In recent years, the application of magnetic nanoparticles as alternative catalysts to conventional Fenton processes has been investigated for the removal of emerging pollutants in wastewater. While this type of catalyst reduces the release of iron hydroxides with the treated effluent, it also presents certain disadvantages, such as slower reaction kinetics associated with the availability of iron and mass transfer limitations. To overcome these drawbacks, the functionalization of the nanocatalyst surface through the addition of coatings such as polyacrylic acid (PAA) and their immobilization on a mesoporous silica matrix (SBA15) can be factors that improve the dispersion and stability of the nanoparticles. Under these premises, the performance of the nanoparticle coating and nanoparticle-mesoporous matrix binomials in the degradation of dyes as examples of recalcitrant compounds were evaluated. Based on the outcomes of dye degradation by the different functionalized nanocatalysts and nanocomposites, the nanoparticles embedded in a mesoporous matrix were applied for the removal of estrogens , accomplishing high removal percentages (above 90%) after the optimization of the operational variables. With the feasibility of their recovery in mind, the nanostructured materials represented a significant advantage as their magnetic character allows their separation for reuse in different successive sequential batch cycles. Advanced oxidation processes (AOPs) are based on the formation of reactive oxygen species (ROS) that lead to the non-specific oxidation of pollutants present in wastewater. These non-selective species possess a high oxidation potential with the ability of removing a wide variety of organic molecules, such as pharmaceutically active compounds (PhACs), endocrine disruptors (EDCs) and personal care products (PPCPs), identified as a potential threat to wildlife and humans when released into the environment ,2. AlthoAOPs include a wide range of different approaches, such as ozone-based processes , semiconMagnetic nano-catalysts must meet some requirements to achieve a viable practical application, i.e., maintaining constant activity over time and adequate physical, chemical and mechanical stability. However, the nature of magnetic nanoparticles (MNPs) results in interparticle interactions, leading to the formation of large aggregates with a lower surface-to-volume ratio . This dr2O2 to the active center of the catalyst as well as to improve its dispersion and separability :[Fe]. When it comes to identifying the contribution of adsorption and H2O2 addition, the controls showed no significant contribution to the total degradation, with total values below 10%.The optimum result of iron concentration is higher than the values reported by other authors applying homogeneous Fenton ,44. The 3O4@PAA/SBA15 was performed to determine the kinetic parameters and half-life of each compound. The study of the kinetic parameters will allow identification of the degradation mechanism and comparison with other works and technologies in the field. For this study, 300 mg L−1 of hydrogen peroxide and 750 mg L−1 of MNP were used under acidic conditions (pH 3.0). The experiments were carried out for 6 h by measuring the concentration at regular intervals, and the data were fitted to a pseudo-first order kinetic model  studying the degradation of Bisphenol A at pH 3, and using a green-synthesized nanoparticles with a concentration of 300 mg L−1. Xin et al. [−1 using CuFeO2/biochar as a catalyst, studying the removal of tetracycline at pH 5 considering an optimum concentration of catalyst of 200 mg L−1. The use of carbon nanotubes as support for magnetite also delivered degradation constants in the same order of magnitude for Bisphenol A and methyltestosterone using similar reaction conditions [3O4@PAA/SBA15 MNPs present, as a unique feature, their excellent recovery and reuse potential. Extending the focus of comparative analysis to other heterogeneous catalytic processes such as photocatalysis using semiconductors , the reported kinetic values are similar for estrogen removal. Oliveira et al. [−1 for EE2 removal, which improved to 0.318 h−1 when an electro-assisted method was applied. Xu et al. [−1.As far as the authors are aware, there are not any published results of estrogen degradation by heterogenous Fenton that include the calculation of kinetic constants. Considering other published research works, estrogen removal showed similar kinetic constants compared to other types of micropollutants using coated and supported Fe-based nanoparticles. As an example, Guo et al.  reportedn et al.  obtainednditions ,48. Aftea et al.  reportedu et al.  achieved2) was evaluated based on their dye removal capacity. Besides its dye removal ability, PAA-coated magnetite showed an improved stability and catalyst recovery in subsequent cycles compared to bare magnetite nanoparticles. Based on these results, the inclusion of a support is also studied, demonstrating that magnetite nanoparticles coated with polyacrylic acid and immobilized on mesoporous silica matrix support (SBA15) improved the efficiency of heterogeneous Fenton reactions, in terms of removal of dyes and endocrine disrupting compounds, achieving removal efficiencies above 90% using the optimized reaction conditions. The ease of recovery of the mesoporous matrix-supported nanoparticles due to their superparamagnetic properties is noteworthy, increasing their suitability for use in sequential batch cycles and thus reducing the operating costs associated with the loss of the catalyst, showing decay values in removal percentages below 5% and recoverability values up to 84%. The results support the use of magnetite-based magnetic nanocatalysts as a cost-effective alternative to conventional Fenton processes in wastewater treatment for estrogen removal, providing kinetic values in the range of 2.6–3.2 h−1 considering the best conditions, similar to other heterogeneous advanced oxidation processes.Despite the proven efficacy of heterogeneous Fenton process for micropollutant abatement using nanostructured catalysts, the drawbacks associated with the discharge of iron in the treated effluent imply the need for approaches that allow the retention of the catalyst and its reuse in successive cycles. In this work, the influence of different coatings (PAA, PEI and SiO


The close association among thyroid metabolism, mood disorders and behavior has long been known. The old and modern uses of thyroid hormones to modulate the expression of depression and bipolar disorder and to improve clinical outcome when used in conjunction with psychotropic medications.A literature search was performed to identify studies investigating the effects of thyroid hormone treatment in patient s with mood disorders.The successful modification of mood disorders with thyroid hormone underscores the association between endocrine and cerebral systems in these disorders. Thyroid hormones have a profound influence on behavior and appear to be capable of modulating the phenotypic expression of major mood disorders. In fact, there is evidence that triiodothyronine (LT3) may accelerate the antidepressant response to antidepressants, and studies suggest that LT3 also may augment the response to antidepressants in refractory depression. Add-on treatment with supraphysiologic doses of levothyroxine (LT4) has shown efficacy in open-label and in placebo-controlled studies, including in rapid cycling and prophylaxis-resistant bipolar disorder, and with acute refractory uni- or bipolar depression. Functional brain-imaging studies (PET) demonstrated that administration of supraphysiologic LT4 improves depressive symptoms in patients with bipolar depression by modulating cerebral activity in the anterior limbic network.The add-on administration of supraphysiologic doses of LT4 is a promising strategy in patients with refractory bipolar and depressive mood disorders. Interest in using thyroid hormones to treat affective disorders arose from observed associations between psychiatric symptoms and thyroid disease states. Behavioral abnormalities in people suffering from myxoedema were first described in a report from the Clinical Society of London, describing severe mental disturbances including irritability, dementia and severe depression . NowadayThyroid hormones have been used as treatment since the early twentieth century . With thAlthough it is well established that symptoms of depression that occur in hypothyroid conditions usually resolve after the euthyroid status has been restored by replacement therapy, treatment effects with thyroid hormones alone, without the concomitant use of standard psychiatric medications, have only rarely been studied in affective disorders. The first reports in the late 1950s were case series with inconclusive results . In a laacceleration studies, which involve the use of supplementation with thyroid hormone at the initiation of an antidepressant trial to speed up time to response; second, augmentation studies, which include the supplementation with thyroid hormone after a 4–8 week trial of an antidepressant has failed or resulted in a partial response. In the third group, the maintenance (prophylactic) studies, adjunctive (add-on) treatment with thyroid hormone has been explored to prevent future episodes in recurrent mood disorders.The use of synthetic thyroid hormones, LT3 and LT4, as adjunctive, supplementary agents in affective disorders, has a long history with the first reports published in the late 1960s/early 1970s , 14. ThrPrange and associates  were theStudies assessing the effects of thyroid hormones in treatment-resistant depression have historically focused largely on LT3 as the augmenting hormone. Case series and at least 13 prospective trials (9 open and 4 controlled double-blind studies) have evaluated the use of LT3 (most studies used 20–50 mcg/d) to potentiate the response to tricyclic antidepressants (TCA) in non-responders to treatment (reviewed in ). The opLT3 has not been prospectively studied in the continuation and maintenance treatment of affective disorders. A retrospective chart review (observation period 20 months on average) showed beneficial effects with hypermetabolic doses of LT3 (average dose 90.4 mcg/d) in patients with bipolar disorders fluorodeoxyglucose (FDG) in (euthyroid) women with refractory bipolar depression. At baseline (pretreatment), bipolar depressed women had functional abnormalities in prefrontal and limbic brain areas compared to healthy controls. Over 7 weeks, the treatment with LT4 significantly improved mood and was accompanied by significant changes in relative brain activity. In particular, LT4 treatment was associated with a widespread relative deactivation of limbic and subcortical structures, including the amygdala, hippocampus, caudate nucleus, ventral striatum, thalamus and cerebellar vermis . We exteThus, the findings provided evidence that administration of supraphysiologic LT4 improves depressive symptoms in patients with bipolar disorder by modulating function in components of the anterior limbic network components that have been implicated in the pathophysiology of mood disorders. These studies, which are the first to use PET technology to demonstrate the effects of treatment with LT4 on regional brain metabolism in patients with bipolar disorder, confirm that thyroid hormones are capable of modulating metabolic function in the mature adult brain, and provide some intriguing neuroanatomical clues as to the locus of that action.1A autoreceptors in the raphe nuclei, and by increasing 5-HT2 receptor sensitivity [The investigation of a potential thyroid–brain metabolic deficit in those patients with treatment-resistant affective disorder is a focus of future research in this area. The key steps of cerebral thyroid metabolism should be considered: the uptake of thyroid hormones into brain; the production of the active hormone LT3; thyroid receptor activity; and the genetics that underpin these various functions . Interacsitivity . Whether


Non-alcoholic fatty liver disease (NAFLD) is the most common hepatic manifestation of metabolic syndromes, and its roots are strongly associated with obesity and insulin resistance. The excess fat induces inflammatory pathways by tissue irritation and progresses to non-alcoholic steatohepatitis (NASH), fibrosis, and has emerged as the most frequent cause of hepatocellular cancer (HCC). This systematic review was structured per the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The evidence was obtained from 13 research articles published in PubMed, Google Scholar, and Science Direct databases, including cross-sectional, case-control, prospective cohort studies, meta-analysis, and systematic reviews. The inclusion/exclusion criteria of free articles, published in English involving humans of mid-age in the last five years were applied. This review highlights findings in 7781 individuals, including non-NAFLD, NAFLD, and NASH positive individuals based on anthropometric measurement, blood samples, FibroScan, flow cytometry, and liver biopsy. The results underscored that the onset of inflammation set on the background of NAFLD starts NASH; the understanding and control of inflammation will help us design definitive biomarkers and treatment modalities. The complex pathogenesis and comparatively slow advancement but high morbidity have led investigators to understand the nuts and bolts for early management and prevention. Lipotoxicity and dysbiosis stimulate the immune system to generate cytokines and chemokines and decline in adipokines. The role of proteinase3 (PR3) and antitrypsin (ATT) ratio and biliverdin reductase (BVR) compel the exploration for non-invasive tests for definitive therapy. Non-alcoholic fatty liver disease (NAFLD) is defined as the deposition of greater than 5% fat in the hepatocytes by histology in non-alcoholics . The sedThe pathogenesis of NAFLD is a multifactorial and multistep process, involving the combination and interaction of genetic, demographic, clinical, and environmental factors, with up to 27% of heritability identified . At the Evolving facts point towards the translocation of swarming intestinal bacteria to hepatocytes through the common portal circulation known as intestinal dysbiosis as the primary instigator in NAFLD , and hasCurrently, liver biopsy is the benchmark for diagnosis and weight reduction with lifestyle modifications form the foundation of the treatment. The evidence of dietary changes with caloric restriction has helped in reducing hepatic fat load, and physical activity including aerobic workout has enhanced hepatic metabolism by increasing fatty acid oxidation, reducing conciliators, and safeguarding against steatosis .In this article, we will elucidate the inflammatory cascade leading NAFLD to NASH by the TLRs, cytokines, and chemokines, alterations in hepatokines and adiponectin characterizing the inflammatory aspect of NAFLD and leukocyte cell-derived chemotaxin2 (LECTS) and natural killer (NK) cells linked to insulin resistance and form the common morbific insult for type 2 diabetes (T2D) and NASH. Though much has been done to treat insulin resistance, we are still learning about the NAFLD-NASH spectrum. The recognition of these intricate processes may help us find new non-invasive and easily accessible biomarkers and medical treatment options like anti-inflammatory agents and antibodies for a largely impacted obese population.The systematic review on NAFLD in the obese population was conducted and documented according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines  using PuA thorough literature search was conducted between April 7, 2021, and July 12, 2021. The following inclusion principles were applied to recognize the studies analyzing the relationship between obesity and NAFLD: human studies with the age limit of 45 years, irrespective of gender, free access to English texts, and articles published in the last five years. The articles used to compile this compact review include traditional reviews, systematic analyses, meta-analyses, clinical trials, case-control studies, cross-sectional studies, and cohort studies.The keywords as shown in Table ResultsThe result was compiled after screening the titles and abstracts relevant to research aims and objectives by two authors. Only moderate-to-high quality studies, focusing on NAFLD to NASH pathophysiology were included in the final analysis, and studies emphasizing solely the treatment, dietary influences, and relation to other diseases were excluded. The final study included a total of 13 papers as shown in the PRISMA flow diagram in Figure Table DiscussionIn this review, we have compiled the information from 13 studies that highlight the activation of the Inflammatory pathway starting from TLRs, the imbalance between pro- and anti-inflammatory cytokines including adipokines in visceral adipose tissue (VAT), and the involvement of NK cells involved in the progression of NAFLD to NASH.The Role of TLRsTLRs are the component of innate immunity and may be present on the cell surface  to detect the bacterial and microbial antigens or associated with the intracellular vesicles  and responsible for identifying the nucleic acid derived particles , but in TLR2 has been proven to be greatly involved in NASH inflammation either by activating Kupffer cell inflammasome or forming heterodimers with TLR6 on recognizing gram-positive diacylated lipopeptides. The animal model with dysfunctional TLR2 did not develop expected insulin resistance and pro-inflammatory surge when diet-mediated NASH was induced . The conTLR4 is expressed on hepatic parenchymal and non-parenchymal cells. The phagocytosis of saturated fatty acid and cholesterol particles, TLR4 is upregulated and promotes tissue injury, inflammation, fibrosis, and progression to HCC and the obese HCC population has shown evidence of TLR4 messenger RNA (mRNA) with interleukin 6 and interleukin 10 (IL6 and IL10) expression ,25. AriaThis role of TLRs is further confirmed by the action of newly developed anti-cytokine drugs like resatorvid (or TAK-242) which is a TLR4 inhibitor . So far Pro-Inflammatory and Anti-Inflammatory CytokinesThe metabolic stress due to lipotoxicity, intestinal dysbiosis, and TLRs activation triggers the immune system. In response, the mobilized M1-type macrophages, monocytes, and hepatic stellate cells along with activated potentiation factors like kinases and transcription factors stimulate the proinflammatory cytokines and chemokines flow . This disequilibrium also shows vanishing anti-inflammatory cytokines  at the same time [High leptin levels and insulin resistance are some of the initial pathways of metabolic syndrome in obesity and NAFLD. The high levels of leptin boost TNF-α and IL-6 release from hepatic stellate cells during early stages to perpetuate inflammation severity  and unwaThe IL-1β is converted to bioactive form by caspase-1 of NLRP3 inflammasome protein complex but Mirea et al. have shown that the neutrophil serine proteases like NE and PR3 have also been used by liver neutrophils to activate it . The stuThis data is in line with the findings of Zang et al. suggesting high sensitivity and specificity of NE/AAT ratio . Since PIn one of the unique case-control studies conducted by Chou et al., the relationship between betel nut chewing and the evolution of NAFLD to NASH and fibrosis was highlighted. They found out that ex and current betel nut consumers had high evolution to fibrosis among NAFLD patients as compared to non-chewers. The toxic metabolites of safrole and arecoline in betel nut tobacco not just self-induce reactive oxygen species but also prompt crossroad CYP2A6 and CYP2C9 of cytochrome p450 system creating an inflammatory torrent of TNF-α and NFκB. The study also expounded that aging, smoking, diabetes, male gender, and obesity were more likely to propagate fibrosis and NAFLD expansion to NASH .By learning more about these inflammatory markers, non-invasive interventions can be devised for rapid testing of newly reported NAFLD and monitoring disease progression. The remarkable success in suppressing CCL24 chemokine by monoclonal antibodies in hepatic inflammation and fibrosis murine models is making our way towards treatment options.Adipokines in VATAdipokines are a group of secretory substances with anti-inflammatory properties produced by adipocytes and play an influential role in hepatosteatosis progressing to fibrosis. The improvement in adipokines and NAFLD post-bariatric surgery is indirect evidence of its importance and positive effect in the process . The keyThe anti-inflammatory and anti-tumorigenic adiponectin is a polypeptide hormone and, along with omentin, not just increases insulin sensitivity but also shows cardioprotective effects . The adiLeptin has a twin role in NAFLD . PrimariThe other key player adipokine expressed in VAT, subcutaneous adipose tissue (SAT), and measured in the serum is chemerin. Chemerin induces chemotaxis and insulin resistance along with fibrogenic MCP-1. The elevated chemerin levels have been described frequently in patients with metabolic syndrome and have been associated with BMI, serum glucose, triglycerides (TG), high-density lipoprotein (HDL) cholesterol levels, and blood pressure .The study by Bekaert et al. demonstrated low VAT chemerin expression and high serum chemerin in obese patients with diagnosed NAFLD as compared to controls but its association with hepatic histopathologic grading is still not clear . Many stNK CellsAs part of the innate immune system, the NK cells originate from common lymphoid precursor cells in the bone marrow. Although NK cells account for only 2-18% of the lymphocytes in human peripheral blood, they compose up to 30% of the lymphocytes in the liver, consisting of half CD56bright and half CD56dim cells with unique phenotypes and functions . NK cellThe results from the study performed on the human circulating NK cells and the hepatic and adipose tissue-resident NK cells by Stiglund et al. suggested that there could be overexpression of circulating NK cell surface ligand (NKG2D) but no changes in influx or repertoire in native NK was noted in hepatic and adipose tissue. NK cells phenotype was even unaffected by the disease severity, degree of fibrosis, insulin resistance, or obesity among the cases and controls. But at the same time, the study presented the limitation that due to multivariate compartments within these tissues the exact function and analysis are difficult in human subjects . In contOne of the studies on the human adipose tissue NK cell population by O'Rourke et al. conducted in 2013 provided an initial insight into the NK cell activity in the adipose tissue. It showed that the activated NK cells in obese populations express high occurrence of cell surface receptors as NKG2D, CD158, CD16dim, NKp46 and CD27+ were highest in visceral adipose tissue samples in comparison to peripheral blood NK cells of obese and no difference was found in peripheral blood NK cells and VAT of the lean comparison group . The impLimitationsThe studies performed have a few limitations. The study participants differ from each other based on geography, comorbid conditions, and lifestyle choices so we cannot apply results to the entire population. The evaluation techniques are also different in each study. A liver biopsy is a touchstone through an invasive procedure and cannot be performed on a large cohort and healthy population for comparison. Due to the associated cost, small groups were studied and not all biomarkers on the inflammatory panel can be tested simultaneously. Also, a few findings can be better evaluated on certain tissue and cell yield. Regardless, we have gathered meaningful information to proceed and explore more preventive and treatment options.The systematic review was designed to present the holistic presentation to learn about the basic inflammatory pathways involved in the development of NAFLD and its progression to NASH. We discussed the natural immunity and provocative components to present the current research being done. We would expect these studies to be conducted at a larger scale at the level of all age groups as the epidemic of obesity is affecting all equally and NAFLD and NASH are becoming the most common cause of hepatic morbidity. This enhanced analysis will benefit future researchers and clinicians to focus on the agenda to develop new non-invasive biomarkers for timely diagnosis and treatment orientation to obtain considerable results for improved and new analytical tests and treatment modalities.


One of the most striking hallmarks shared by various neurodegenerative diseases, including Parkinson’s disease, Alzheimer’s disease and amyotrophic lateral sclerosis, is microglia-mediated and astrocyte-mediated neuroinflammation. Although inhibitions of both harmful proteins and aggregation are major treatments for neurodegenerative diseases, whether the phenomenon of non-normal protein or peptide aggregation is causally related to neuronal loss and synaptic damage is still controversial. Currently, excessive production of reactive oxygen species (ROS), which induces mitochondrial dysfunction in neurons that may play a key role in the regulation of immune cells, is proposed as a regulator in neurological disorders. In this review, we propose that mitochondrial DNA (mtDNA) release due to ROS may act on microglia and astrocytes adjacent to neurons to induce inflammation through activation of innate immune responses (such as cGAS/STING). Elucidating the relationship between mtDNA and the formation of a pro-inflammatory microenvironment could contribute to a better understanding of the mechanism of crosstalk between neuronal and peripheral immune cells and lead to the development of novel therapeutic approaches to neurodegenerative diseases. Neurodegenerative diseases are rare hereditary disorders of the central nervous system that cause a slowly progressive loss of function of specific neuron populations and their connections. In addition to Alzheimer’s and Parkinson’s diseases (AD and PD), these also include amyotrophic lateral sclerosis (ALS). Among these, AD is formed by the deposition of a proteolytic product of the amyloid precursor protein, called amyloid β-protein (Aβ), which leads to mitochondrial disorders . Aβ isol2O2), superoxide anion (O2−) and highly reactive hydroxyl radicals (HO·) [Numerous studies have shown that reactive oxygen species (ROS) are closely associated with neurodegenerative diseases. ROS significantly promote the degeneration of neurons by regulating the function of biomolecules. ROS target different biological molecules  and biological processes (nucleic acid oxidation and lipid peroxidation). The brain requires large amounts of oxygen to function properly and can be considered a factory of free radicals, as well as a hotspot for neurodegenerative diseases. ROS forms involved in neurodegeneration include hydrogen peroxide (Hls (HO·) .Mitochondria are responsible for the production of ATP through the electron transport chain and oxidative phosphorylation. They are also involved in the production of molecules to overcome oxidative stress, programmed cell death and respiratory functions of the cell. Mitochondrial enzymes rich in various oxidoreductases and mitochondrial dysfunction are thought to be responsible for the generation of ROS in the cellular environment . Neurona+/CD45 low/high phenotype play an important role in neuroinflammation [Increasing evidence indicates that mitochondrial dysfunction is associated with a variety of neurodegenerative diseases. Neurodegeneration results in the loss of the normal anatomical structure and function of the human nervous system. One of the main functions of mitochondria is to provide energy in the oxidative respiration of cells. When glucose metabolism or electron transfer is perturbed by genetic or exogenous factors, the respiratory chain complex is compromised, which can cause the inhibition of the electrochemical gradient, deficits in energy production and ultimately neurodegeneration ,48. Mitoammation . Astrocyammation .Neuroinflammation is a key driver of neurodegenerative diseases and can trigger and exacerbate neuronal damage. Here, we describe the role of mtDNA release induced by stress injury in the formation of an inflammatory microenvironment in neurons. We further investigated the mechanism by which mtDNA promotes neuroinflammation, providing a new strategy for the development of targeted drugs, and the treatment of neurodegenerative diseases.“Leaky” mtDNA from damaged mitochondria caused by mitochondrial dysfunction is a significant source of mitochondrial danger-associated molecular patterns (mtDAMPs). Mitochondria share several features with bacteria, including a double membrane structure and a circular genome with non-methylated CpG sites independent of nuclear DNA replication. Given this similarity, once released into the cytoplasmic or extracellular space, mtDNA fragments activate innate immunity and inflammation, such as DAMPs, which are similar to pathogen-associated molecular patterns (PAMPs). This occurs through a molecular cascade reaction that includes binding to Toll-like receptor 9 (TLR9) and subsequent activation of stimulators of the interferon gene (STING) pathway . We specROS production is thought to be an upstream step in the oxidative damage of mitochondrial proteins, membranes and mtDNA. This is partly due to the fact that mitochondria are a major source of endogenous ROSs, which are produced in the mitochondrial matrix and escape from metabolic processes and electron transport chains during oxidative phosphorylation. ROSs are produced by electron transport chains and metabolic redox reactions, which can result in mtDNA mutations or deletions, oxidative damage to the respiratory chain, lipid peroxidation and overall mitochondrial dysfunction. When neurons are exposed to oxidative stress, their internal mitochondria produce ROS, leading to mitochondrial dysfunction and the possible release of oxidized mtDNA . Moreove2O2 stimulation in the voltage-dependent anion channel 1/3(VDAC1/3) knockout mouse fibroblasts (MEF) when compared with wild-type MEF. Additionally, in the presence of mtDNA, VDAC1 trimer and higher-order oligomer formation was increased, suggesting that oxidatively stressed mitochondria release mtDNA fragments through pores formed in the outer mitochondrial membrane by VDAC oligomers [−/−Casp11 and −/−GSDMD mouse microvascular endothelial cells (MVEC) and found that intracellular LPS-induced mtDNA release was dependent on caspase-11 and Gasdermin D [−/−NLRP3 mouse bone-marrow-derived macrophages, induced them with LPS, treated them with ATP and found that NALP3 also mediates mtDNA release [As a DAMP, mtDNA can cause cellular stress. Many studies have been conducted on how mtDNA is released into the cytoplasm/extracellular space. Kim et al. found that cytoplasmic mtDNA was reduced both at basal levels and after Hligomers . Riley eligomers . Huang edermin D . Similardermin D . Taken t release . It has  release . Moreove release . Further release . Accumul release .STINGgt/gt was not sensitive to ganciclovir (GCV)-induced interferon responses compared with microglia from wild-type mice [The mtDNA released by neurons also has an effect on adjacent microglia. Liao et al. used mtDNA extracted from purified mitochondria, which were then transfected into cGAS knockout mice and tamoxifen-induced cGAS or HDAC3 knockout microglia, and demonstrated that the cGAS/STING pathway in microglia was activated by mtDNA and that HDAC3-regulated p65 acetylation and nuclear localization in microglia transcriptionally activated cGAS expression and enhanced cGAS/STING pathway activation, which exacerbated the inflammatory microenvironment . Mathur ype mice . Tsilionype mice . The accype mice . Thus, mype mice . HoweverMitochondrial oxidative stress is an important factor leading to the disruption of mtDNA integrity and mtDNA release, which in turn may act on surrounding astrocytes by entering the cytoplasm or being secreted extracellularly via vesicles/exosomes, permeability pores and other means. In a variety of neurodegenerative diseases, TAR DNA/RNA binding protein 43 (TDP-43) exhibits aberrant aggregation and localization within neurons and glial cells. It has been shown that TDP-43 can cause dysregulation of mitochondrial proteins, leading to mitochondrial oxidative stress . Yu et aIn neurodegenerative diseases, mtDNA serves as the initiation point of neuroinflammation and how it activates the inflammatory response. The mtDNA released by neuronal cells acts on nearby microglia and astrocytes via exocytosis. The cGAS/STING pathway plays a unique and critical role in neuroinflammation and neurodegenerative diseases as one of the important aberrant cytoplasmic DNA monitors. As the primary cytoplasmic DNA receptor for microglia and astrocytes, cGAS can be activated by mtDNA that is aberrantly localized in the cytoplasm. As shown in STINGgt/gt, Parkin−/− and PINK1−/− mice and their hybrids, demonstrating that Parkin and PINK1 prevent the development of a cytosolic response by clearing both damaged mitochondria to prevent increases in cytosol and circulating mtDNA to prevent inflammation and neurodegeneration, thereby alleviating symptoms of PD through mitochondrial autophagy [TDP-43 mutant allele A315T, STING-deficient mice, and the resulting progeny from crossing these two lines to demonstrate that TDP 43 releases mtDNA through the mPTP permeability pore and activates the cGAS/STING pathway thereby exacerbating ALS [The release of mtDNA due to mitochondrial dysfunction may be an important marker in neurodegenerative diseases. Leurs et al. compared the levels of free mtDNA in the cerebrospinal fluid of patients with relapsing-remitting multiple sclerosis (RRMS), patients with progressive multiple sclerosis (PMS), controls with various neurological diseases, and healthy controls and found that PMS patients had mtDNA concentrations that were nonspecifically elevated . Podlesnutophagy . Yu et ating ALS . Jauhariting ALS . mtDNA rting ALS .In neurodegenerative diseases, neuronal oxidative stress randomly induces stress and damage to internal mitochondria, which respond to this stress, thereby causing an increase in neuronal response to metabolism and an increase in ROS production by the respiratory chain complex that disrupts the integrity of mtDNA to be released from the internal mitochondria. A portion of the damaged mtDNA that accumulates in the cytoplasm activates the intracellular cGAS/STING pathway to promote the secretion of pro-inflammatory factors such as IL-1β by neurons to promote the inflammatory phenotype of microglia and astrocytes near neurons, as well as to recruit leukocyte infiltration in response to neuroinflammation. In addition, most of the mtDNA may be released extracellularly via exosome vesicles and acts on neighboring microglia and astrocytes, which take up the mtDNA via endocytosis or binding to the corresponding receptors. This uptake activates the cGAS/STING pathway within these immune cells and, thus, type-I-interferon-mediated immune responses, as well as the classical NF-κB signaling pathway, to promote secretion of pro-inflammatory factors TNF-α, IL-6. The action of mtDNA released by neurons on themselves and surrounding microglia and astrocytes maintains the microenvironment of neuroinflammation.All members of the IL-1 family are expressed by endogenous brain cells but at low levels. High levels of IL-1β and IL-18 are found in a variety of neurodegenerative diseases . When thIn conclusion, inflammation creates an essential microenvironment for the development of neurodegenerative diseases. In neurodegenerative diseases, neurons receive oxidative stress that causes mitochondrial dysfunction, and the damaged mitochondria promote the release of mtDNA, which acts on surrounding microglia and astrocytes, causing an immune response . TherefoCurrently, there is a relative lack of research on how the IL-1 family specifically affects the mtDNA/cGAS/STING pathway. Our previous studies have shown that IL-33 can regulate macrophage metabolism by influencing its polarization ,93, and Currently, inhibition of harmful proteins and aggregation is the mainstay of treatment for neurodegenerative diseases. However, whether there is a causal relationship between the phenomenon of abnormal protein or peptide aggregation and the occurrence of neuronal loss and synaptic damage is still controversial. Recently, therapeutic strategies to improve the brain’s energy metabolism to combat neurodegenerative diseases have also been an emerging therapeutic concept, and therefore mitochondria play an irreplaceable role as a source of brain function. In this review, we proposed that mitochondrial ROS-induced mitochondrial dysfunction, resulting in the release of mtDNA, may be a key mechanism contributing to neurodegenerative diseases. However, due to the complexity of mitochondrial ROS metabolism, good efficacy may not be obtained with only one antioxidant. Therefore, a more complete approach is needed in the future tools of antioxidant therapy to reduce the damage to neurons caused by ROS. Moreover, mtDNA is a central point of regulation of neuroinflammation in the microenvironment of neuroinflammation, where microglia interact strictly with neurons and their differential activation. Disruption of the homeostasis of the inflammatory microenvironment may lead to altered phenotypes of microglia. Targeting the mtDNA/cGAS/STING pathway to reverse the phenotypic changes of microglia and astrocytes may be a new strategy for the treatment of neurodegenerative diseases.


Peripheral nerve injuries (PNIs) continue to present both diagnostic and treatment challenges. While nerve transections are typically a straightforward diagnosis, other types of PNIs, such as chronic or traumatic nerve compression, may be more difficult to evaluate due to their varied presentation and limitations of current diagnostic tools. As a result, diagnosis may be delayed, and these patients may go on to develop progressive symptoms, impeding normal activity. In the past, PNIs were diagnosed by history and clinical examination alone or techniques that raised concerns regarding accuracy, invasiveness, or operator dependency. Magnetic resonance neurography (MRN) has been increasingly utilized in clinical settings due to its ability to visualize complex nerve structures along their entire pathway and distinguish nerves from surrounding vasculature and tissue in a noninvasive manner. In this review, we discuss the clinical applications of MRN in the diagnosis, as well as pre- and postsurgical assessments of patients with peripheral neuropathies. Peripheral nerve injuries (PNIs) are common, with an incidence of 16.9 per 100,000 citizens in the United States.Historically, suspected peripheral neuropathies have been diagnosed by clinical presentation, nerve biopsy, and nerve conduction studies (NCSs).Visualization of nerve structures can help determine the location and/or cause of nerve dysfunction.In 1992, Filler et al introduced magnetic resonance neurography (MRN), an imaging technique that takes advantage of nerve tissue's longer T2 isolation time.MRN is becoming more frequently employed as it is noninvasive and allows physicians to differentiate between neurologic and nonneurologic disorders and locate damaged nerve segments to narrow the differential diagnosis.The authors performed a systematic review of the MEDLINE and EMBASE databases using a comprehensive combination of keywords and search algorithm according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The literature search focused on clinical data regarding MRI and MRN imaging modalities for peripheral nerves and was undertaken to define the current understanding of MRN as a method of evaluating nerve structure and function.Due to the depth of the brachial plexus and its complex anatomy, brachial plexus lesions are often difficult to characterize and treat.A common context for diagnostic use of MRN is Parsonage–Turner's syndrome (PTS), also known as acute idiopathic brachial plexus neuritis. PTS is broadly characterized by the inflammation of nerves in the chest, shoulders, and arms which commonly presents as pain and flaccid paralysis of the corresponding musculature.In addition to its diagnostic utility, MRN has shown promise in evaluating postsurgical recovery via T2 nerve signal intensity and signs of muscle degeneration. One article described three patients with C5 to C7 injuries who underwent Oberlin transfer .Upper extremity (UE) nerve entrapments often present with mild symptoms, such as numbness or tingling that can progress to pain and/or functional deficits.On MRN, a normal median nerve appears hypointense on a T1-weighted (T1W) image and isointense to minimally hyperintense on a T2-weighted (T2W) image along the course of the arm.Aggarwal et al described a case of an 18-year-old man presenting with a medial epicondyle fracture and elbow dislocation treated via closed reduction of the elbow and cast immobilization. After cast removal, he reported progressive numbness and paresthesia over the median nerve distribution of the forearm and hand with inability to form a fist. NCS revealed median nerve dysfunction at the elbow, but did not identify the exact site of entrapment.−3mm2/s) was significantly higher than that of the control group (1.06 × 10−3mm2/s) (p < 0.01).Carpal tunnel syndrome (CTS) is a common cause of median nerve entrapment. Bao et al conducted a study of 47 CTS patients who were diagnosed primarily by clinical examination with a positive Tinel's and Phalen's signs, followed by NCS and electromyography (EMG).In a study of 30 CTS patients, MRN images taken prior to decompression surgery showed an increased signal change in the proximal median nerves, proximal nerve swelling at the level of the pisiform and distal radius, and increased flattening of the distal median nerve in the majority of CTS patients, compared with the healthy controls.Similar to the median nerve, ulnar nerves show changes in both T1W and T2W intensities when damaged, particularly in the wrist region.Chhabra et al reported a case of a 46-year-old woman with a history of five ulnar nerve surgeries on the right elbow that presented with many months of pain and paresthesia over the ulnar nerve distribution in her forearm and hand as well as decreased pinch and grip strength, which began after a submuscular ulnar nerve transposition—her most recent surgery.Recently, diffusion tensor imaging (DTI) and tractography have been used in conjunction with MRN to detect proximal lesions and distinguish between multifocal and focal-compressive ulnar neuropathy at the elbow in cases where clinical examination and EMG/NCS were unable to localize the site of nervous deficiency.Current literature suggests that MRN is a more precise tool than NCS and EMG in determining the exact site of UE nerve entrapment and assessing nerve recovery following surgical intervention. Furthermore, when symptoms persist despite attempted interventions, MRN can be used to augment the diagnostic algorithm and may reveal pathologies not previously suspected based on physical examination and NCS/EMG.Patients with lower extremity entrapment neuropathy, an under-recognized cause of pain and functional impairment, often present with nonspecific symptoms, which makes it difficult to distinguish from more common, nonneurologic causes of pain.While various lower extremity nerves have been described in the literature, the majority of reports address causes of sciatic neuropathies. Intra- or extra-articular hip pathology and lumbar radiculopathy present with symptoms similar to sciatic nerve entrapment.Chitranjan et al described the case of a 55-year-old woman with 2 years of left gluteal swelling and left lower extremity pain. A computed tomography scan revealed herniation of the sigmoid colon through the greater sciatic foramen and atrophy of the gluteal muscles.Polesello et al reported a case of a 42-year-old woman with 17 years of recurrent left-sided low back pain, which was initially diagnosed as L5-S1 spondylolisthesis with a herniated disc. Despite treatment with physiotherapy, analgesics, and an L5-S1 arthrodesis, the patient's pain became progressively worse, preventing her from work.One prospective study included 239 patients presenting with leg pain in the sciatic nerve distribution and either inconclusive diagnosis or unsuccessful prior lumbar spine surgery.Recent studies have employed the use of MRN in diagnosing lower extremity nerve abnormalities that may not have been detected by alternative methods such as MRI, NCS, and EMG. In the case of sciatic neuropathy, MRN can be used to determine the site neurologic compromise and distinguish between its various causes such as piriformis syndrome or compression due to trauma.Diabetic peripheral neuropathy (DPN) is common in diabetics and can cause irreversible nerve damage. DPN also increases risk of diabetic foot ulcers which, if left untreated, may lead to amputation.MRN studies of patients with type 1 diabetes (T1D) and type 2 diabetes (T2D) have shown that T1D patients with DPN have a higher T2W hyperintense lesion load compared with T2D patients with DPN, and T2D patients with DPN have a higher T2W hypointense lesion load compared with T1D patients with DPN.Furthermore, studies have shown that lesions extend over longer distances in patients with painful DPN versus those with nonpainful DPN or no DPN, and the maximum length of a lesion is positively correlated with the per cent coverage of T2W hyperintense nerve lesions along a full nerve.MRN is a promising imaging tool that may be employed as a diagnostic marker in the early detection of DPN in diabetic patients. Early detection may assist in preventing the progression of DPN to debilitating conditions that negatively impact quality of life.PNI, including brachial and lumbar plexus injuries, occurs in ∼5% of all traumas.After closed injuries, it may be difficult to distinguish between nerve injuries that have the potential to recover on their own (neurapraxic and axonometric) from those that do not (neurotmetic) and require surgery.One study of 20 patients with features of traumatic brachial plexopathies assessed correlation between MRN and subsequent intraoperative findings.In another study, 11 infants with birth-related brachial plexus injuries were assessed to compare MRN versus EMG, since EMG is a painful procedure done without sedation and can be difficult to perform in children. MRN findings included muscle denervation changes, T2 prolongation along the affected brachial plexus, and enhancement or thickening of nerve roots.Advantages of MRN include early characterization of the location and grade of nerve injury and improved accuracy when compared with NCS and EMG. Published data suggest that MRN could be a valuable addition to the diagnostic algorithm for traumatic nerve injuries, especially when traditional assessment tools are not able to accurately diagnose nerve conditions.Delayed diagnosis of PNI leads to delayed treatment, thus narrowing the scope of available treatment options. Ultimately, this can result in long-lasting functional deficits and impaired quality of life.MRN also provides excellent soft tissue contrast, allowing for visualization of downstream muscle injury and high contrast resolution between surrounding fat and vascular structures.Recently, there has been an increased interest in combining MRN with DTI and diffusion-weighted imaging (DWI). DWI can be used to study the extracellular movement of water, and it capitalizes on the difference in diffusion properties in various types of tissue.Nerve-specific contrast agents such as Gadofluorine M, though not yet used clinically, have shown promise in nerve imaging.MRN has been utilized in a variety of nerve injury patterns to provide insights beyond traditional assessment modalities. The current literature indicates that MRN has the potential to improve clinical outcomes, particularly in nerve defects that are either difficult to detect or require early intervention.


The search for new therapeutic opportunities to target cancer metastasis is crucial for the improvement of cancer treatment. One of the characteristics of tumoral and metastatic cells is the capacity to reorganize their metabolism, together with the ability to grow faster, migrate and form new tumours in distant sites. Therefore, the pharmaceutical inhibition of metabolic pathways represents a promising strategy to specifically target metastatic cells, especially in colorectal cancer metastasis.Metabolic adaptation is emerging as an important hallmark of cancer and metastasis. In the last decade, increasing evidence has shown the importance of metabolic alterations underlying the metastatic process, especially in breast cancer metastasis but also in colorectal cancer metastasis. Being the main cause of cancer-related deaths, it is of great importance to developing new therapeutic strategies that specifically target metastatic cells. In this regard, targeting metabolic pathways of metastatic cells is one of the more promising windows for new therapies of metastatic colorectal cancer, where still there are no approved inhibitors against metabolic targets. In this study, we review the recent advances in the field of metabolic adaptation of cancer metastasis, focusing our attention on colorectal cancer. In addition, we also review the current status of metabolic inhibitors for cancer treatment. Cancer metabolic reprogramming is nowadays considered an important hallmark of cancer, receiving every time more attention from cancer researchers and oncologists. However, almost a hundred years ago, Otto Warburg was the first to observe that cancer cells had an increased glucose uptake and lactate production, even in the presence of oxygen . Later, The metabolic pathways commonly altered in cancer are related to the main sources of energy and building blocks for sustaining survival and growth of cancer cells . Thus, tThe relationship between all these metabolic changes and other features of cancer has also been largely studied. . The metAt advanced stages of cancer development, certain cells with cancer stem cell phenotype acquire the capacity to invade the surrounding tissues, intravasate to circulation and finally arrest a new organ or tissue, which is known as the metastatic process . The celThe metabolic reprogramming associated with the metastatic process is still widely unknown, although some researchers have been working in that specific field during the last few years. The first step of metastasis, which is the transition of the metastatic stem cells from an epithelial to a mesenchymal state, is observed to be accompanied by metabolic changes that frequently are similar to the metabolic reprogramming associated with tumorigenesis and tumour growing .Glycolysis and glycolytic enzymes are enhanced when cells undergo epithelial-mesenchymal transition (EMT), as it happens in tumour phenotypes compared to healthy cells. Energetic and biosynthetic precursors demand in metastatic cells are even more important than in differentiated non-tumorigenic cancer cells. Besides, glycolytic enzymes have also non-metabolic functions related to EMT. For example, GAPDH, G6PD, LDHA and PKM2 have been identified to colocalise with 14-3-3ε protein, gelsolin and G protein β1 subunit at invadopodia . On the Furthermore, the relationship between metabolic reprogramming and EMT is also explained by other factors that induce both processes, which is the case of TGFβ, TNFα signalling pathways as well as HIF1α. Induced by low oxygen levels in the less vascularised tumour zones or else by certain oncometabolites, HIF1α induces EMT-related genes such as Snai1, Slug, and Twist and regulates the autocrine mobility factor (AMF), which is the secretion form of the glucose phosphate isomerase that also mediates EMT . In turnIn the final steps of glycolysis, the overexpression of enzymes that catalyse lactate production from pyruvate, as well as its transport such as LDH5, MCT1, and MCT4 also correlate with migration capacity . The aciThe evidence about mitochondrial alterations related to the invasion capacity and EMT is even more contradictory than the one related to tumorigenesis and cancer cell growth. An example of that is the role of the transcription factor PGC-1α that stimulates mitochondrial biogenesis. On one hand, in breast cancer, PGC-1α correlates with the formation of distant metastasis and it is observed to be overexpressed in invasive cells, promoting mitochondrial biogenesis, and enhanced mitochondrial activity , as wellResults about mitochondrial respiration associated with EMT are also contradictory. Both upregulation  and downAlterations in amino acid metabolism, such as enhanced glutamine uptake and glutaminolysis, have also been related to EMT and metastasis ,53. AnotCAV1, CD36, MLXIPL, CPT1C, CYP2E2) are also associated with EMT of multiple cancer types and metastasis and poor prognosis [Lipid metabolism has also been observed to be implicated in invasion and metastasis. The storage of produced lipids and cholesterol in lipid droplets and destabilisation of lipid rafts driven by FASN is associated with aggressiveness and maintenance of a mesenchymal state trough the induction of VEGF and TFGβ signalling ,57. Howerognosis ,64.When cells finally reach circulation, they become detached. Normal detached cells compromise glucose uptake and result in depressed mitochondrial potential and decreased ATP levels. However, in circulating tumour cells, constitutively active Akt or other signalling pathways are observed to prevent a decrease in ATP levels triggered by the loss of cellular attachment ,66. DetaFor example, anchorage-independent cells are observed to be dependent on cytosolic IDH1 and produced citrate in a reductive carboxylation manner, that entered to the mitochondria and through IDH2 generated NADPH, which is necessary to compensate high ROS levels . The ErbCancer cells release certain factors in the blood that favour a premetastatic niche in the place of the metastatic site. A metabolic example of that is the secretion of miR-122 that suppress glucose uptake and downregulates PK in the premetastatic niche, which will increase glucose availability for cancer cells once they reach the metastatic site, among other examples ,76. In fRegarding metabolic adaptations that are observed to be specific of the organ of origin, there is evidence that breast cancer metastatic cells expressed PPP enzymes differently, being the brain the place with the highest expression . AnotherWhen breast cancer cells metastasise specifically to the lung, another study reveals that metastatic cells become dependent on pyruvate carboxylase in response to the pyruvate availability of the lung microenvironment . AntioxiWhen the site of metastasis is the liver, breast cancer cells reduce mitochondrial metabolism as a response to the low oxygen levels that exist in some parts of the liver by overexpressing PDK1 that inhibits PDH and reduces oxidative phosphorylation . The samRegarding bone metastasis, breast cancer cells show increased serine biosynthesis through the expression of phosphoglycerate dehydrogenase (PHGDH), phosphoserine aminotransferase, (PSAT1), and phosphoserine phosphatase (PSPH). This is probably occurring because serine is released and required for the formation of osteoclasts that would help bone metastasis through osteolysis . AnotherFinally, in lymph node metastasis, fatty acid oxidation is observed to acquire an important role. Enzymes from fatty acid oxidation are overexpressed by the transcriptional coactivator yes-associated protein (YAP) that were probably activated by bile acids accumulation in the metastasis of lymph nodes through the vitamin D receptor .In the specific context of colon cancer, it is observed that at the very initial steps of tumorigenesis and progression, cancer-initiating cells present a significant metabolic reprogramming, mainly characterised by increased glycolysis, TCA cycle, cysteine, and methionine metabolism . These cApart from direct Wnt pathway-related metabolic alterations in the adenoma stage also MYC is observed to be upregulated, probably induced by Wnt, bringing an early metabolic reprogramming including the major biosynthetic pathways such as PPP, nucleotide synthesis, fatty acid synthesis or one-carbon metabolism. At the same time, MYC reduces the expression of genes related to mitochondrial metabolism such as PGC-1α . FurtherOther metabolic alterations that are observed to be related to colorectal cancer initiation are the overexpression of GLS1, GLUD1, and the mitochondrial aspartate glutamate carrier 2 (SLC25A13), which are associated with tumour growth and poorer outcome in colon cancer ,95. ManyAs explained before, the metabolic alterations underlying metastatic colorectal cancer are much less studied than other cancer types such as breast cancer. However, some relevant studies compared primary tumour and metastatic colon metabolism and found that expression of ACSL and SCD correlates with poor clinical outcome inducing energetic capacity and invasive and migratory characteristics . AnotherOther studies have discovered some of the metabolic properties that would allow colorectal cancer cells to survive in circulation and initiate metastasis in the liver: Detached colorectal CTCs overexpressed enzymes of the fatty oxidation pathway such as CPT1A, the rate-limiting enzyme of this pathway. Such enzymes are found to be essential for anoikis resistance and survival of CTCs from the colon . FurtherFinally, some studies found a characteristic pattern in colorectal cancer cells that metastasised to the liver . This isMetabolic reprogramming has been exploited for cancer therapy almost since the beginning of chemotherapy, with the discovery of aminopterin for the treatment of childhood acute lymphoblastic leukaemia  and nowaAnother commonly used antimetabolites are those inhibiting the nucleotide synthesis directly in biosynthetic pathways of purines and pyrimidines, which are also overactivated in cancer cells. There are purine analogues (6-mercaptopurine and 6-thioguanine), which target amidophosphoribosyltransferase (ATase), and pyrimidine analogues (5-fluorouracil and its prodrug capecitabine), which target thymidylate synthase (TS) . There aFortunately, many other metabolic-based strategies are approved or in clinical trials that are more specific for cancer cell metabolic reprogramming. This is the case of the treatment of cancers that present mutations in IDH1 or 2, mainly glioblastoma multiforme (GBM) or acute myeloid leukaemia (AML). Specific inhibitors for IDH1 , IDH2 (AG-221 or enasidenib) or both IDH1/2 (AG-881) have been proven to be effective and approved or currently in clinical trials, being enasidenib and ivosidenib the first mutant-IDH FDA-approved for AML patients in 2017. However, not all IDH-mutant tumours have a good response to the treatment or exhibit resistance, therefore, further exploration of the possible drug combinations is needed .Other metabolic targets are related to glucose metabolism and the TCA cycle. Alpha-enolase (ENO1) is one of the enzymes of glycolysis that is shown to be overexpressed and contribute to the Warburg effect and its inhibition using phophonoacetohydroxamate (PhAH) or SF-2312 has been proven to be effective for many cancer cell lines in vitro . InhibitGlutamine addiction is another metabolic feature of cancer cells that is being exploited for therapy. Targeting GLS 1 activity with the inhibitor telaglenastat (CB-839) is currently in clinical trials for the treatment of renal cell carcinoma or other solid tumours in combination with other drugs ,118. HowOther chemotherapeutic treatments related to amino acid metabolism are the depletion of circulating arginine using PEG-BCT-100 or AEB-1102, which are human recombinant arginases or arginine deaminases, respectively. Such therapies are in phase I of clinical studies in combination with immune checkpoint inhibitor antibodies , in the Finally, fatty acid metabolism rewiring in cancer is also currently being explored for cancer therapy. Specifically, de novo lipogenesis is a requirement of cancer cells and targeting fatty acid synthase (FASN) using the TVB-2640 FASN inhibitor is nowadays in phase I or II clinical trials for breast, lung and colon cancers . InhibitMany metabolic inhibitors are being tested for the treatment of colorectal cancer in in vitro models, in preclinical models and also in clinical trials such as GLS1 or FASN inhibitors. An example of specifically targeting a colorectal cancer metabolic adaptation is 3-bromopyruvate sensitivity, taking advantage that the colorectal cancer cells present overexpression of MCT1, induced by the Wnt pathway ,126. In Although there are many metabolic alterations observed in colorectal cancer and other cancer types have started to benefit from metabolic strategies, none of these metabolic approaches is being used nowadays in the treatment of colorectal cancer . TherefoThe metabolic adaptation of cancer has been studied since the Warburg effect was discovered in the 1920s. However, in the last decades, there has been an increasing number of studies evidencing that metabolic changes are crucial not only for tumorigenesis and cancer development but also for metastasis. Multiple examples of metabolic alterations underlying the different steps of the metastatic processes have been discovered in recent years. Despite some of the actual chemotherapies already target the metabolism of cancer cells, there is great hope for the development of more effective metabolic inhibitors. The present review displays evidence that there is an urgent need to better understand the metabolic mechanisms underlying colorectal cancer metastasis, and that there is a huge window of therapeutic opportunities targeting metastatic colorectal cancer metabolic plasticity that should be exploited in the future by means of drug combinations that compromise this metabolic adaptability.


Advances in proteomic and metabolomic technologies have accelerated our understanding of multiple aspects of cancer biology across distinct tumour types. Here we review the current state-of-the-art in the use of proteomics and metabolomics in soft tissue sarcomas. We highlight the utility of these Omics-based methodologies to identify new drug targets, synthetic lethal interactions, candidate therapeutics and novel biomarkers to facilitate patient stratification. Due to the unbiased and global nature of these profiling methods to assess the levels of protein expression, post-translational modifications such as phosphorylation and glycosylation as well as key metabolites, many of these findings have broad applications not just in specific histotypes but across multiple STS subtypes. Specific examples of proteomic and metabolomic findings that have led to the development of early phase clinical trials of investigational agents will be discussed. While promising, the use of these technologies in the study of sarcoma is still limited, and there is a need for further research in this area. In particular, it would be important to integrate these approaches with other Omics strategies such as genomics and epigenomics as well as implement these tools alongside clinical trials in order to maximize the impact of these tools on our biological understanding and treatment of this group of rare diseases of unmet need. Sarcomas are a group of rare neoplasms originating from the malignant transformation of primary, multipotent mesenchymal stem cells which differentiate into bone, muscle, adipose and cartilage tissues ,2. They Treatment of localized primary STS consists of surgery either with or without radiation . Around Proteomics represents the entire complement of proteins within the cell and includes post-translational modifications (PTMs) and protein-protein interactions ,17. GiveOne of the earliest large-scale proteomics studies in STS was performed by The Cancer Genome Atlas (TCGA) Research Network which carried out a multi-platform molecular analysis of 6 histological subtypes . Here thTwo recent studies have sought to integrate genomics and proteomics in order to extract useful biological information about two histological subtypes, namely UPS and rhabdomyosarcoma (RMS). Toulmonde et al. performed integrative genomics and proteomics (DIA-MS) to categorize UPS clinical specimens into subgroups with distinct immune phenotypes, clinical outcomes and therapeutic sensitivities •. The auIn addition to measuring total protein levels, it is possible to quantitatively measure PTMs including glycosylation and phosphorylation using mass spectrometry. In a pioneering study by the Bovée laboratory, the authors used mass spectrometry imaging to measure the N-glycans in myxoid liposarcoma (MLS) •. Given Phosphorylation is one of the most prevalent, widely studied PTMs intimately involved in almost all cellular processes . To gainOne key feature of cancer cells is metabolic adaption to meet the high demands of cell growth and division . Metabol13C glucose in the glycolytic pathway, tricarboxylic acid (TCA) cycle and pentose phosphate pathway was studied in 5 STS cell lines after FBP2 re-expression. The authors showed that FBP2 re-expression resulted in metabolic adaptation with a decrease in glucose uptake and conversion to lactate, a decrease in four TCA intermediates  and glutamate and aspartate. They also observed an increase in intermediates of other metabolic pathways such as amino sugars, erythrose-4-phosphate and gluconolactone. Gene set enrichment analysis of RNA-seq data from FBP2 expressing cells revealed reduced enrichment of gene signatures for known oncogenic pathways such as MYC targets, OXPHOS, G2/M checkpoint regulation and E2F targets. This study highlights the importance of FBP2 in STS biology and its pleiotropic impact on multiple key oncogenic pathways. Further studies are required to translate these preclinical findings into actionable therapeutics for evaluation in clinical trials.A recent study utilized several metabolomic techniques such as unbiased mass spectrometry and isotope tracing to demonstrate that the loss of fructose-1,6 bisphosphatase 2 (FBP2) is a key event during sarcoma progression and a potential therapeutic target ••. GlucoAnother aspect of STS biology is amino acid metabolism. Several studies have identified vulnerabilities in glutamine, arginine and tryptophan metabolism in STS. Circulating glutamine is one of the most abundant amino acids and a vital source of nitrogen for biosynthetic reactions. It serves as a source of carbon to replenish the TCA cycle and produce glutathione and as a precursor for lipid and nucleotide synthesis . MitochoIn one study, Lee et al. showed that glutamine metabolism is particularly important in UPS •. The auIn another study, Lemberg et al. showed that malignant peripheral nerve sheath tumours (MPNST) were highly dependent on glutamine as MPNST cells required higher glutamine concentrations post-glutamine starvation to rescue their growth compared to healthy peripheral cells and immortalized Schwann cells . They foArginine is a semi-essential amino acid, obtained from dietary sources and synthesized via the urea cycle in the kidneys . One of Tryptophan (Trp) is an essential amino acid, and a small fraction of its free levels in the body is utilized for protein synthesis and production of certain neurotransmitters and neuromodulators ,51. The In a single-arm, phase 2 multicentre study with 57 advanced STS patients (NCT02406781) comprising mostly LMS and UPS subtypes (54% of the cohort) evaluating the safety and efficacy of the anti-PD-1 antibody pembrolizumab in combination with metronomic cyclophosphamide . PD-L1 bTaken together, these studies demonstrate the power of proteomics and metabolomics to generate new hypotheses for biological interrogation, novel therapeutic candidates for drug discovery, previously undescribed molecular subgroups within histological subtypes and predictive and prognostic biomarkers. In some cases, these findings have been translated into clinical trials or have offered insights into why some therapies have failed in the clinic. Coupled with the latest technological innovations in mass spectrometry and imaging approaches, including new methods for single-cell analysis, it is anticipated that further discoveries in STS will be forthcoming.


Efferocytosis, i.e., engulfment of dead cells by macrophages, is a crucial step during tissue repair after an injury. Efferocytosis delineates the transition from the pro-inflammatory phase of the inflammatory response to the recovery phase that ensures tissue reconstruction. We present here the role of efferocytosis during skeletal muscle regeneration, which is a paradigm of sterile tissue injury followed by a complete regeneration. We present the molecular mechanisms that have been described to control this process, and particularly the metabolic control of efferocytosis during skeletal muscle regeneration. Macrophages control the inflammatory response after tissue injury. One of their primary duties is to cleanse the cell debris of the injured area through phagocytosis. Engulfment of cell debris has been described as non-phlogistic phagocytosis, then efferocytosis. Indeed, macrophages that have ingested dying cells act as dampeners of inflammation. Seminal studies demonstrated in vitro and in vivo that recognition and engulfment of apoptotic cells (through exposed phosphatidylserine) reduce the secretion of pro-inflammatory effectors by phagocyting macrophages to the benefit of the secretion of TGFβ and PGE2 ,2,3. OncHere we present the role of efferocytosis during skeletal muscle regeneration, which is a paradigm of sterile tissue injury followed by a complete regeneration. Skeletal muscle is composed of myofibers which are syncytial cells with hundreds of myonuclei. These multinucleated cells are post-mitotic. Therefore, skeletal muscle regeneration relies on the properties of muscle stem cells (MuSCs), the satellite cells that implement a myogenic program, in coordination with the cells of their close environment to rebuild new functional myofibers. The presence of macrophages exerting phagocytotic functions in regenerating muscle was already described in 1957 . In 1993Adult skeletal muscle regeneration relies on the powerful properties of muscle stem cells that follow a cell-autonomous program of adult myogenesis, controlled by the sequential expression of Myogenic Regulatory transcription Factors (MRFs). Upon muscle damage, MuSCs exit the quiescent state (where they highly express Pax7) and start to proliferate (they down regulate Pax7 expression and express MyoD). Some myoblasts undergo asymmetric division giving rise to a small pool of cells that self-renew as satellite cells and to myogenic progenitors. The latter exit the cell cycle and enter into terminal differentiation, and become differentiated myocytes (extinguishing Pax7 expression and expressing Myogenin and MRF4). Finally, the differentiated cells fuse together to form myotubes, then grow into newly formed myofibers that maturate, reinnervate and recover their contractile function ,7.Although MuSCs exhibit a powerful cell-autonomous capability to implement myogenesis , it was shown that their close surrounding environment strongly impacts on their behavior, and therefore on the efficacy of the myogenesis process. One of the major components of this environment are immune cells and particularly macrophages, which are present in huge numbers (representing about 75% of hematopoietic cells in the cardiotoxin model). Macrophages accompany each step of the regeneration process, where they play a plethora of non-immune roles towards the cells present in the regenerating area .Unless indicated, the results described in this review are coming from the widely used model of post-toxic injury muscle regeneration, where injury is provoked by the intramuscular injection of a toxin that damages almost the entire muscle  . In thispos CX3CR1lo CCR2pos) enter the injured muscle through the CCL2/CCR2 axis and become pro-inflammatory macrophages (Ly6Cpos CX3CR1lo CCR2pos F4/80lo). Pro-inflammatory macrophages sustain the mounting of the inflammatory response and exert various functions towards cells residing in the muscle. This phase lasts no more than 3 days, and the resolution of inflammation takes place between day 2 and day 3 after injury (in the cardiotoxin model). The resolution of inflammation, operated by efferocytosis (see below) gives rise to anti-inflammatory/recovery/restorative macrophages (Ly6Cneg CX3CR1hi CCR2neg F4/80hi) that decrease the inflammatory response, and act on a variety of cell types to ensure tissue repair, angiogenesis, and matrix remodeling [A few hours after a toxic (notexin or cardiotoxin) injury, pro-inflammatory circulating monocytes . Recovery macrophages also stimulate angiogenesis, which is coregulated with myogenesis. Finally, they promote the differentiation of FAPs into fibroblasts and their production of collagen; moreover, recovery macrophages secrete extracellular matrix components and enzymes involved in matrix remodeling [Cells that are known to be targeted by macrophages during muscle regeneration are MuSCs, endothelial cells (ECs) and fibroadipogenic precursors (FAPs), which are multipotent mesenchymal cells. During the first days after injury, i.e., during the pro-inflammatory phase, Ly6Cmodeling ,8,9.A very interesting feature is the similarity between the sequences of macrophage activation profile in post-injury skeletal muscle regeneration in mouse and in human. Indeed, after an experimentally exercise-induced muscle injury of human healthy muscle, areas of regeneration discriminate early regenerating areas where pro-inflammatory macrophages and proliferating MuSCs coexist, from late regenerating areas where recovery macrophages are associated with differentiating MuSCs ,11.The powerful capacity of skeletal muscle to regenerate relies on this sequence of cell interactions that must be tightly ordered in time and space for an efficient functional recovery. In this aspect, the transition from the pro-inflammatory phase to the recovery phase is of utmost importance.neg cells from the blood or the shift of the inflammatory profile of Ly6Cpos macrophages already present in the injured muscle. A series of evidence argue for the second hypothesis. First, depletion of circulating monocytes (using liposome-clodronate) from day 3 after injury does not impact the regeneration process [pos enter into the injured muscle where they further lose Ly6C expression with time in the regenerating muscle [KO animals, where Ly6Cneg monocytes are barely present in the circulation, both muscle regeneration and kinetics of macrophage inflammatory profile are similar to the wildtype [pos inflammatory monocytes enter the injured muscle, and convert into recovery macrophages, proceeding to the resolution of inflammation, as has been shown in all injured tissues investigated so far.The presence of recovery macrophages that start the second phase of muscle regeneration could be due to either the recruitment of Ly6C process . Second,g muscle . Finallywildtype . TherefoSeveral molecular mechanisms were identified to control this key moment during skeletal muscle generation, delineating the stopping of the pro-inflammatory response and the start of the tissue repair. They include CREB-C/EBPβ, p38/MKP-1/AKT, meteorin-like/Stat3/IGF-1, RhoA-Rock1/Nfix and Annexin1/CaMMKβ/AMPK pathways. When those pathways are inhibited, muscle regeneration is strongly impaired ,17,18,19neg recovery macrophages strongly express Secretory Leukocyte Peptidase Inhibitor (SLPI) [KO animals (due to the deficit of monocyte entry into the injured muscle) [First evidence of efferocytosis in skeletal muscle came from in vitro experiments where pro-inflammatory macrophages shift their inflammatory profile upon the ingestion of dead MuSCs . Mechanir (SLPI) , which er (SLPI) . In vivor (SLPI) ,21,22. T muscle) . CX3CR1  muscle) ) and the muscle) .KO macrophages for engulfment of dead myoblasts. In this study, using whole body KO animals, Mer deficiency was shown to impact both the resolution of inflammation and myogenesis [Three recent studies have shown the direct requirement of mechanisms involved in efferocytosis as necessary for muscle regeneration . Scavengogenesis . In the ogenesis . These t2O2 and H2O treatment, leading to mainly apoptotic and necrotic cells in the culture, respectively. Although the mechanisms by which macrophages recognize necrotic cells must be investigated, the shift of macrophage inflammatory phenotype was observed with both apoptotic and necrotic myoblasts.The in vitro studies described above have used various ways to induce myoblast (C2C12 cell line or primary human and mouse myoblasts) death including HThe role of cellular metabolism on macrophage inflammatory status and function has been increasingly studied during recent years ,28. The A recent study  demonstrUcp2 in mouse reduces macrophage phagocytic activity in vivo in a model of dexamethasone-induced thymocyte apoptosis [Mitochondria have also been shown to be important for efferocytosis. For instance, efferocytosis up-regulates the levels of the mitochondrial membrane uncoupling protein (UCP)2 in an in vitro model of apoptotic thymocytes engulfed by LR73 phagocytes, while genetic depletion of poptosis . Similarpoptosis .Risp depletion in macrophages results in an impaired resolution of inflammation after myocardial infarction in mouse. Although these results appear in contradiction with the study by Morioka et al., they may reflect the requirement of a sequential activation of different metabolic pathways to sustain the efferocytic process and to promote the resolution of inflammation. Thus, exhaustive in vivo kinetics analyses are required to accurately characterize this metabolic sequence.More recently, a molecular network linking efferocytosis and the production of the IL-10 anti-inflammatory cytokine, through the stimulation of mitochondria activity, was identified in murine macrophages after myocardial infarction . Metabolper se, but its expression is mandatory in macrophages for the subsequent acquisition of the recovery phenotype [Upon efferocytosis, macrophages ingest bodies that can be as large as them, thus bringing a strong metabolite load that needs to be externalized or catabolized to restore the macrophage metabolic homeostasis. In vitro studies have shown that lipids from the membrane of the engulfed cells accumulate into macrophages and generate ligands for liver X receptor (LXR) and peroxisome proliferator-activated receptor (PPAR) family members, which are nuclear receptors regulating lipid export and metabolism . Engulfmhenotype . Efferochenotype , which hhenotype .Another mechanism to restore the efferocyte metabolic balance was recently identified. Zhang et al. showed in murine macrophages that the intensity of the IL-10 production triggered by efferocytosis varies depending on the membrane content of the engulfed cells. Although the engulfment of inert beads does not stimulate mitochondrial fatty acid oxidation or IL-10 synthesis, increased fatty acid levels in the membrane of the ingested apoptotic cells results in an increased IL-10 production by efferocytic macrophages . This supos and Ly6Cneg macrophages at various time points of regeneration indicates that their metabolic change, from a glycolytic to an oxidative metabolism, shortly precedes the shift of their inflammatory profile. Moreover, longitudinal analysis of the cell profile along the regeneration process indicates that more than expressing or not the Ly6C marker, the time after injury is the driving force of the metabolic and inflammatory changes in macrophages [During skeletal muscle regeneration, it was shown that the metabolic profile of macrophages evolves with time. Indeed, RNAseq of isolated Ly6Crophages ,39.One of the main metabolic sensors of the cells, 5′AMP kinase (AMPK), is activated in macrophages upon efferocytosis, triggering microtubule and actin reorganization ,41. On tDuring skeletal muscle regeneration, AMPK activation is required in macrophages for their acquisition of the recovery phenotype in vitro and in vivo . IntriguAlthough skeletal muscle is highly powerful for regeneration, there is some interest to expedite the regeneration process, for instance in the case of infection that disrupts the inflammatory response , in the One of the most prescribed anti-inflammatory compounds are glucocorticoids. In vitro, glucocorticoids shift macrophages towards a recovery phenotype, which exert their repair function on MuSCs . The gluInterestingly, Annexin A1, which is a pro-resolving molecule, is required for the increased macrophage phagocytic activity induced by dexamethasone ,52. AnneEfferocytosis is a key event that ensures an efficient skeletal muscle regeneration, to end the pro-inflammatory response and to start the repair process, as in many other tissues. There are many questions that remain to be investigated. One is to decipher the heterogeneity of macrophages during skeletal muscle regeneration to establish whether some subsets of macrophages are specifically in charge of efferocytosis and what are their specific responses during the process. Additionally, metabolic rewiring of macrophages upon efferocytosis deserves further investigation to establish if there are some specificities in the muscle tissue. Finally, as nicely exposed by Rothlin et al. , efferoc


Tendon disorders represent a very common pathology in today’s population, and tendinopathies that account 30% of tendon-related injuries, affect yearly millions of people which in turn cause huge socioeconomic and health repercussions worldwide. Inflammation plays a prominent role in the development of tendon pathologies, and advances in understanding the underlying mechanisms during the inflammatory state have provided additional insights into its potential role in tendon disorders. Different cell compartments, in combination with secreted immune modulators, have shown to control and modulate the inflammatory response during tendinopathies. Stromal compartment represented by tenocytes has shown to display an important role in orchestrating the inflammatory response during tendon injuries due to the interplay they exhibit with the immune-sensing and infiltrating compartments, which belong to resident and recruited immune cells. The use of stem cells or their derived secretomes within the regenerative medicine field might represent synergic new therapeutical approaches that can be used to tune the reaction of immune cells within the damaged tissues. To this end, promising opportunities are headed to the stimulation of macrophages polarization towards anti-inflammatory phenotype together with the recruitment of stem cells, that possess immunomodulatory properties, able to infiltrate within the damaged tissues and improve tendinopathies resolution. Indeed, the comprehension of the interactions between tenocytes or stem cells with the immune cells might considerably modulate the immune reaction solving hence the inflammatory response and preventing fibrotic tissue formation. The purpose of this review is to compare the roles of distinct cell compartments during tendon homeostasis and injury. Furthermore, the role of immune cells in this field, as well as their interactions with stem cells and tenocytes during tendon regeneration, will be discussed to gain insights into new ways for dealing with tendinopathies. Tendons are strands of fibrous connective tissues with a great tensile strength that connect muscles to bones and allow force transfer . AlthougIndependently of the underlying cause of tendon disorders, it is generally accepted that a state of inflammation is frequently associated to such condition which is responsible for a poor prognosis. The core role of inflammation in tendinopathies  has alsoInflammation can occur in tendons because of mechanical insults and other multifactorial co-triggering factors including genetic, epigenetic, systemic diseases, drugs, and in particular aging and metabolic diseases, that play a role in defining the severity of the pathological pattern and its resolution ,6. The dAdult tendons have a limited natural healing potential which is ascribable to the peculiar tissue biology characterized by a low cellularity, hypo-vascularity and low tendon metabolism ,16, and Until now, no successful targeted treatments have been developed, but it is generally accepted that understanding the key inflammatory pathways affecting tendon ECM regulation and homeostasis are critical in designing future targeted therapies for tendinopathy . An innoAccording to these premises, this review aims to compare the role of different tendon cell compartments in tendon homeostasis and during tendon injuries. Moreover, the role of immune cells in this field and their crosstalk with tenocytes and stem cells during tendon regeneration will be discussed to acquire insights on novel strategies applied to deal with tendon inflammatory state. It is of great importance to evaluate the interplay between the injured/healing tendon and the immune system as a model to study and better understand inflammatory processes and in particular understanding this special constellation to further expand the knowledge about other inflammatory diseases.Tendon by its nature is exposed to many mechanical loads throughout the whole life. It is characterized by a hierarchical and anisotropic structure, which allows the tendon to perform its mechanical function without breaking down. This feature is thought to be the reason due to which tendons evolve low demand for cellular and matrix turnover . CollageStromal, immune-sensing, and infiltrating compartments represent three different cell compartments that contribute each to a complex milieu of tendon homeostasis A 3]..3].The stromal compartment includes matrix components , tenoblasts, and mostly tenocytes. Recent studies have highlighted the concept of tendon cells heterogeneity ,27,28,29Tissue-resident tenocytes sense mechanical stimuli and translate them into molecular response. This leads to the modulation of ECM synthesis and its remodeling due to the changes in protein and gene expression and brings the tendon to its new homeostatic setpoints, allowing it to adapt to its function within the new environment A 22]. T. T22]. TResident cells of the tendon immune-sensing compartment express immune-cell-related markers  . They coFinally, the infiltrating compartment cells are recruited through the activation of stromal and resident immune cells that, in normal circumstances, represents a homeostatic inflammatory response A 3]..3].Tendon homeostasis is achieved by a continuous remodeling process facilitated by matrix metalloproteases (MMPs) and matrix metalloprotease inhibitors (TIMPs), which involves the deposition by tenocytes, belonging to the stromal compartment, of new ECM, including the synthesis of collagen type I (COL1), decorin, biglycan, versican, scleraxis (Scx), tenascin C, and aggrecan A 7,46,4,446,47. During tissue injury, the activation of inflammatory mechanisms and the innate immune system is evident within the tendon matrix microenvironment and probably assist in dysregulated homeostasis. The three cellular compartments participating in tendon homeostasis, listed in the previous paragraph, contribute each to a complex milieu of inflammatory mechanisms during tendinopathies B. After The influential stromal compartment that contains the centrally resident tenocytes is accountable for tissue remodeling and repair. Due to the presence of immune receptors on their cell-surface, resident tenocytes secrete cytokines and chemokines in both autocrine or paracrine manner and can be driven toward an activated inflammatory phenotype B 71]. T. T71]. T2), promoting pro-inflammatory macrophage (M1) and T cell activity. These inflammatory cytokines have some effects, including the up-regulation of VEGF production together with the enhancement of the synthesis of MMPs, including MMP-1 MMP-3, MMP-8, MMP-9, and MMP-13, whose role is inducing matrix destruction. They alter ECM homeostasis, foster remodeling, increase biomechanical adaptiveness, and stimulate tenocyte apoptosis . Di. Di71]. Although the existence of several publications concerning the tenogenic differentiation of stem cells by expressing tendon-related markers and their role on improving ECM deposition, few studies have concentrated on the role of stem cells and/or their derivatives on blunting tenocytes’ inflammatory phenotype. In particular, Manning et al. examined the ability of adipose-derived mesenchymal stem cells (ASCs) on modulating the inflammatory phenotype of tenocytes subjected to macrophages in a tri-culture system . When teOther studies were not limited to the effects of stem cells on modulating the inflammatory phenotype of tenocytes, but they also evaluated the effects of stem cells’ paracrine factors including microvesicles (MVs) and conditioned media (CM) on tenocytes’ behavior. In two studies conducted by Lange-Consiglio et al., they demonstrated that the use of MVs secreted by amniotic mesenchymal stem cells (AMSCs) induced a downregulation in the expression of pro-inflammatory markers by tenocytes with no effect on the proliferation of peripheral blood mononuclear cells (PBMCs) ,138. In Taking together, the rescue of tenocyte resident cells from acquiring an inflammatory phenotype can counteract the release of pro-inflammatory mediators within the damaged tendon tissues under the effect of stem cells and their derivatives, including MVs and CM, which in turn can start ECM synthesis and remodeling driven by tenocytes.The tissue regenerative advances provided by stem cells and/or their secretomes are to be mediated by their role in suppressing the proinflammatory response and improving the resolution of tendon disease. This novel approach could spare inflammation-induced healing moieties and stimulate robust and rapid ECM repair.Regenerative medicine comprehends all biological therapeutic strategies to improve tissue lesion and disfunction . For exaIn order to define the ideal stem cell to stimulate tendon healing, in vitro protocols have been attempted to test the tenogenic plasticity of different stem cell source sometime in combination with in vivo preclinical studies ,149. TheMSCs are largely used in tendon regeneration as they have proven to have regenerative potential . MSCs ca2, which is generally considered a proinflammatory lipid mediator, also exhibits powerful and context-dependent anti-inflammatory effects [2 that could be able to switch M1 macrophages into M2 or improve the selective activation of M2 [2 is produced through a COX-2-dependent Prostaglandin E synthase (arachidonic acid pathway) [2 in MSCs plays a significant role in macrophage polarization/metabolic changes [2 synergizes with colony stimulating factor (CSF-1), resulting in CSF receptor transactivation, which supports monocyte/macrophage survival, differentiation, and motility [2 contained within CM, obtained from human amniotic membrane (hAM) and human amniotic MSCs (hAMSCs), is involved in the immunomodulatory activity of hAM and hAMSCs. In addition, this study revealed that the exposition of PGE2 to T cells induced a slight reduction in their proliferation together with an inhibition of PBMCs proliferation confirming hence its anti-inflammatory role [PGE effects . In vitron of M2  with anton of M2 . PGE2 ispathway) . By co-c changes . These smotility . Moreoveory role .2 that inhibit T cell proliferation [2, Notch1, and IL-10 [In vivo experiments demonstrated that MSCs can influence M2 polarization also by secreting the paracrine IL-1Ra  and by mferation . In factferation . Moreoveferation . MSCs inferation ,176. MSCnd IL-10 . MSCs cand IL-10 ,178 as tnd IL-10  needed fnd IL-10 ,180.The immunomodulation of MSCs in tendons has not been largely investigated. However, an in vitro study on adipose derived mesenchymal stem cells (ADMSCs) demonstrated their ability to modulate the immune response during tendon inflammation . In thisMSC immunomodulation after transplantation has been investigated in different body districts such as bone  and live6 cell density was compared to 1 × 106. Surprisingly, the lower concentration resulted the best to induce regeneration and decrease inflammation. The high dose of MSCs resulted in increased pro-inflammatory cytokines at day 5  and increased expression of IL-12 at day 14 after injury and transplantation. On day 14, M1 macrophages were present in the wounded site treated with high dose of MSCs while a sensible decrease of M2 was detected compared to controls. The low dose of MSCs resulted in a small wound size after injury and MSCs inoculation. These results, together with the significant changes in procollagen I, proliferating cells, and endothelialization suggests that MSCs can affect the cellular response during healing in a dose-dependent manner [Evidence reported the in vivo healing effects of untreated and TNF-α primed MSCs derived from BM in rat Achilles segmental defect model . Rat Acht manner .Currently the most promising stem cells source for tendon TE are the tendon stem cells (TSCs) that were discovered in several species as human, horse, rabbit, rat, and mouse ,186,187 However, even if TSC may represent the ideal therapeutic stem cell source, their effect is poor in term of cells availability, in vitro expansion without phenotypic drift  and in i+ M1 cells in the early healing phase was detected, while the CD146+ TSCs increased correlated to an increased IL-10 expression. IL-10 has a crucial anti-inflammatory role in tendon healing inhibiting the release and the action of proinflammatory cytokines and monocytes/Mfs [It was proposed a role of TSCs in modulation of inflammation and matrix metalloproteinase (MMP) activities during tendon healing. TSCs treated with connective tissue growth factor (CTGF) express anti-inflammatory IL-10 and TIMP-3 through c-Jun N-terminal kinase (JNK) and signal transducer and activator of transcription 3 (STAT3) signaling, that play essential roles in tendon healing . In sampytes/Mfs . In addiytes/Mfs ,195. Witytes/Mfs ,197,198,ytes/Mfs  ant TIMPAmniotic epithelial Stem cells (AECs) are recently emerging as a new source of stem cells to be used for tendon regeneration ,20,200.Their teno-regenerative role has been rigorously demonstrated by combining in vitro with ex vivo evidence ,129,200.Ovine AECs (oAECs) demonstrated to have immunomodulatory properties in vitro inhibiting lymphocyte proliferation both in transwell co-culture or in cell-to cell contact systems in vitro ,203. The2) and cytokines, avoiding the proliferation of T cells and recruitment of lymphocytes, as summarized in According to the evidence described above, stem cells such as MSCs or AECs can influence the immune response during tendon healing prevalently modulating the M1 to M2 switch, secreting anti-inflammatory cytokines , preventing the production of pro-inflammatory molecules  therapy was also proven to exhibit a positive effect in tendon healing . In the The gene therapy can be considered in order to enhance the immunomodulatory properties of stem cells ,226. StuMoreover, BM-MSCs genetically modified to overexpress prostaglandin I synthase (PGIS) protected damaged heart and restored cardiac function in a mouse model  and modiThe immunomodulatory properties of stem cells have a fundamental importance in tendon regenerative medicine, but literature lacks on this argument. Certainly, more investigations are needed to deeply comprehend the influence of different stem cells sources on the regenerative process, to choose the suitable type to be used in vivo.Taking all together, although the promising results obtained with the use of stem cells in vivo in preclinical studies, their translation into the clinic often is difficult to achieve. Considering the complexity and functionality of tendon tissue, the main cause could be due to the fact that the experimental induced tendon injury  does not represent in full a tendinopathy model and this can explain the different outcomes between the preclinical in vivo studies and clinical trials . AdditioInflammation is rapidly becoming recognized as a significant factor in tendon illnesses. Advances in understanding the inflammation’s underlying the cellular mechanisms and the molecular pathways involved have given more insights into tendon illness, as well as the circumstances that may aggravate it, but this information could lead to the development of new therapeutical approaches to be applied for tendinopathies.Regenerative medicine represents an innovative strategy to deal with tendinopathies and the resulting inflammation. The application of stem cells or their derived secretomes has shown a great potential in improving tendon regeneration allowing to hypothesize the development of cell-based and cell-free strategies to modulate the immune response in tendon injuries. Indeed, it has been demonstrated that different immune cells together with secreted immune modulators participate to control and promote tissue regeneration. Understanding the crosstalk between the host tissue, stem and immune cells might greatly modulate the immune reaction resolving hence the inflammatory response and avoiding the formation of fibrotic scar tissue. Therefore, a prolonged inflammation could be avoided by modulating the immune cells either with bioactive immunomodulating molecules, such as the stem cells’ secretomes, or by directly applying stem cells with an immunomodulatory potential, as AECs, which in turn might lead to an improved tendon regeneration. Encouraging prospects in this field are represented by stimulating whether macrophage polarization towards anti-inflammatory phenotype whether stem cell recruitment and penetration within the damage tissue accompanied with an enhancement of their immunomodulatory properties. Taking together, understanding the interplay between different tendon cell compartments together with the potential role of stem cells in modulating the inflammatory response due to their immunomodulatory properties helps to develop new innovative strategies to deal with tendinopathies. Evaluating the immune-related mechanisms within healthy and injured tendon tissues serves to clearly assess the different inflammatory processes for further targeted strategies to deal with tendinopathies.