The possibility of reprogramming human somatic cells to pluripotency has opened unprecedented opportunities for creating genuinely human experimental models of disease. Inborn errors of metabolism (IEMs) constitute a greatly heterogeneous class of diseases that appear, in principle, especially suited to be modeled by iPSC-based technology. Indeed, dozens of IEMs have already been modeled to some extent using patient-specific iPSCs. Here, we review the advantages and disadvantages of iPSC-based disease modeling in the context of IEMs, as well as particular challenges associated to this approach, together with solutions researchers have proposed to tackle them. We have structured this review around six lessons that we have learnt from those previous modeling efforts, and that we believe should be carefully considered by researchers wishing to embark in future iPSC-based models of IEMs.The online version contains supplementary material available at 10.1007/s11154-021-09671-z. Inborn errors of metabolism (IEMs) are heritable monogenic disorders that often present congenitally with multi-system manifestations affecting various organs. Commonly, gene mutations in IEMs lead to inadequate enzyme or transporter activity and result in the accumulation of toxic substrates or a deficiency of essential metabolites. Although individually rare, IEMs are collectively quite common, with an estimated incidence of 1 in 4000 newborns . Even thin vivo has been challenging because transgenic animal models of these disorders are often nonviable or show early mortality [Gaining a better understanding of the pathophysiological bases underlying IEMs is absolutely critical in order to develop new therapeutic agents. Animal models have provided invaluable insights into the pathophysiology of IEMs, but there remain questions of translatability to humans due to interspecies differences in physiology –6. Additortality . Becauseortality  has openortality –12, for In this review, we focus on the use of iPSC technology to model IEMs and how these models provide a valuable tool to set up innovative treatment approaches for particular IEMs. We discuss published iPSC models of inherited metabolic diseases and summarize the main lessons learnt from these efforts.In 2006, Takahashi and Yamanaka published a major technological breakthrough in the field of disease modeling, describing a method for reprogramming terminally differentiated adult dermal fibroblasts into cells with a gene expression profile and developmental potential similar to those of embryonic stem cells (ESCs) , 13, 14.iPSC technology offers the possibility to generate patient-specific cells for modeling human diseases. While animal-based models have provided valuable insights into the pathogenic mechanisms of numerous human diseases –17, subsin vitro models. iPSC-based models can provide disease-related phenotypes in cell types relevant for the specific disease, thus representing a clear advantage over the use of fibroblasts or immortalized cell lines. For example, hiPSC-derived cells are more vulnerable to the toxic effects of substrate accumulation that are characteristic of several IEMs [in vitro drug testing, gradually lose their hepatic functions during culture and are unable to proliferate [Identification of novel therapeutic approaches requires recapitulating key features of IEMs and relevant pathogenic mechanisms, a frequent limitation of conventional ral IEMs –28 and dral IEMs . For inhral IEMs . Similarliferate . TherefoOnly fifteen years after the original description of induced reprogramming to pluripotency, enormous progress has been made in stem cell biology and regenerative medicine using iPSC technology , 32–34. www.ssiem.org/resources/resources/inborn-errors-classification). Although disease modeling remains a challenge in the context of IEMs, to date, dozens of these disorders have been modeled to some extent using patient-specific iPSC. We have identified from scientific literature a total of 107 IEMs for which iPSC lines have been generated, referenced with a total of 291 publications , among which lysosomal disorders have attracted special attention , Pompe disease, or NPC was found to be reduced when compared with that of healthy somatic cells , 49–53. IEMs encompass a plethora of highly diverse disorders. The presence and severity of the disease can also vary within individuals carrying the same pathogenic mutation. In any case, the known IEM mutations observed in patients are not developmentally lethal, and the early stages during the embryonic development are not severely compromised. In this regard, although the reprogramming efficiency might occasionally be reduced, the metabolic defects underlying IEMs do not seem to affect the generation and maintenance of iPSCs, which has been accomplished for dozens of these disorders. This finding reinforces iPSC technology as an important experimental tool to provide valuable insights into the pathophysiology of these diseases, further encouraging researchers to apply this powerful approach for IEM modeling.A defining characteristic of pluripotent stem cells is their potential to differentiate into cells of all three germ layers. However, a limiting factor regarding the use of iPSCs is, precisely, the variability in their differentiation potential. Not only the inter-individual differences among iPSC may have a strong impact in the differentiation capacity toward a specific cell type, but also between hiPSC clones from the same individual , 59. TheIrrespective of the origin, phenotypic interline variability of iPSCs complicates assigning specific genotypes to disease-related cellular phenotypes. In this sense, the use of targeted nucleases as gene-editing tools is increasingly being used to counteract such variability, enabling the generation of isogenic controls that only differ in the presence/absence of the genetic variants under study. The versatility of targeting almost any locus in the genome to generate the desired targeted genetic modification becomes essential for the interpretation of the results and to strengthen the relationship between the genotype and phenotype.OAT) and HPRT1 gene [LDLR gene, respectively, restoring low-density lipoprotein-cholesterol (LDL-C) uptake [GLA gene. Differentiated cardiomyocytes and vascular endothelial cells from gene-corrected iPSC lines displayed restored levels of α-gal A protein [HEXB gene was corrected. In this way, cerebral organoids from mutant and gene-corrected iPSC were developed, demonstrating that accumulation of GM2 ganglioside was diminished and the neuronal differentiation was not impaired in isogenic controls when compared with the mutant HEXB line [The earliest attempts at generating sequence-specific changes in IEMs-derived iPSC were established with BAC- or AAV-based vectors targeting the ornithine-δ-aminotransferase  uptake –72. Rece protein , 74. CRIEXB line .The use of genetic engineering and iPSC technology is a powerful combination especially for ultra-rare diseases where patients’ samples for iPSC generation are particularly limited. In order to overcome this limitation, specific mutations can be introduced in healthy control iPSC. Although the complex genomic background of real patients is not recapitulated when using control iPSC, these efforts provide valuable insights into the pathogenesis of specific gene mutations , 77.The generation of iPSCs from healthy and diseased individuals allows capturing the complex genomic background from each individual. Genomic variability may impact in the differentiation capacity towards the cell of interest or even in the observed phenotypes. Thus, formally ascribing the appearance of disease-related phenotypes to the presence of particular gene mutations often requires the analysis of isogenic control cells that only differ in the specific mutation of interest. Although the studies combining iPSCs and gene-editing techniques for the modeling of IEMs are still only a small fraction Fig. B, there in vivo [For decades, the identification of novel compounds for treating human conditions has relied on high-throughput screening systems primarily based on cellular assays. Most cell-based screening assays have used either immortalized tumor-derived cell lines, in which the desired molecular target is heterologously expressed, or primary cells that better resemble the functions and phenotypes found in vivo . Althougin vivo , 79.Although iPSC technology has facilitated the understanding of disease pathogenesis and the impact of compound modulators, drug development for monogenic diseases, including those related to IEMs, is still challenging , 80, 81.+ as a potential drug candidate that could increase not only ATP levels, but also the expression of all mitochondrial-encoded electron transport chain genes examined in vitro and in vivo [in vitro and in vivo [However, the use of iPSC-based models of IEMs for medium- and high-throughput screening approaches is scarce to date. This most likely reflects the inherent challenges in generating disease affected cell types at high scale and purity . In a st in vivo . Recentl in vivo . In a se in vivo .Over the past few years, compound-screening assays using iPSC-derived cells has emerged as a new powerful strategy for the pharmaceutical industry, facilitating target and lead identification, and lead optimization. However, there is still a long way to go in the context of IEMs. iPSCs are particularly important given that they can be reproducibly cultured in high abundance and give rise to different cell types from the same individual, which facilitates optimization for compound safety, selectivity and efficacy. In addition, the importance of stringent quality controls and well defined and established workflows at every stage of the process will be indispensable for the identification of novel compounds, and thus for the successful use of iPSC-based platforms for drug discovery and preclinical studies.in vitro using iPSC-based strategies than late-onset diseases. This could be linked to the fact that current iPSC differentiation protocols yield cells with immature or fetal-like characteristics, but it may reflect the difficulty of recapitulating aging, a major risk factor in many late-onset diseases, in standard laboratory conditions. These limitations notwithstanding, several studies have decribed the appearance of disease-related phenotypes in iPSC-based models of PD, Huntington disease, and Alzheimer’s disease [Theoretically at least, almost any genetic disease lends itself to be modeled employing iPSC-based technology. However, this strategy has proved so far to be more amenable for tackling monogenic diseases associated to highly penetrant disease-causing mutations, as opposed to environmentally modulated, sporadic or diseases of unknown cause . Congeni disease , 96. AltCanals et al. generated an iPSC-based experimental model of Sanfilippo type C syndrome, a lysosomal storage disorder with progressive neurodegeneration . Differein vivo situation [One of the main challenges associated with iPSC-based experimental approaches is the relative immaturity of iPSC derivatives obtained with current differentiation protocols, which are typically carried out under standard two dimensional (2D) culture conditions , 99. It ituation , 102.For example, Akbari et al. reported on the generation of functional hepatic organoids for Citrullinemia type I that recapitulated important disease-related phenotypes such as the decrease in ammonia detoxification capacity . Similarin vivo-like phenotype with multi-organ capabilities for IEM disease modelling [Organoids are valuable tools for precision medicine and, in combination with genetic-engineering approaches, can be used to directly test the role of pathogenic mutations in a controlled environment. Despite the numerous advantages of organoids over conventional 2D cell culture systems, some limitations remain, such as the relative lack of standardized protocols to generate organoids and the absence of vascularization and of complex inter-organ communication. To address current technical challenges in organoid research, the integration of organoids with microfluidic on-a-chip devices is emerging as an advanced, yet complementary, bioengineering approach. Organ-on-a-chip devices are able to control the biochemical and biophysical microenvironment, resulting in increased tissue maturation and vascularization, and offering a more odelling –108. A podelling .The ability to reprogram somatic cells to iPSCs is gradually changing the way we develop experimental disease models, especially for rare monogenic diseases, offsetting the limited number of patients available worldwide, the difficulty in gaining access to the mostly affected tissues, and the lack of bona fide experimental animal models. The combination of human iPSC-based technology and site-directed genome edition constitutes an exciting and powerful platform for complex disease modeling and drug screening. However, despite the promising advantages offered by combining these two technologies, important limitations and challenges need to be taken into account if disease models are to be exploited to their fullest Fig. . EffortsIn conclusion, carefully designed and properly controlled iPSC-based models of IEMs recapitulate key features of the disease phenotype and respond to pharmacologic manipulation predictably. As such, iPSC-based models of IEMs have enabled uncovering the role of novel pathogenic mechanisms in sialidosis and NPC, identifying new drug compounds potentially effective for DGUOK deficiency and hypercholesterolemia, and developing novel drug candidates and target pathways for GM1 gangliosidosis, among many other examples of success. Whereas remarkable progress has been made over the past decade, iPSC technology is still in its infancy and important challenges will need to be addressed. Of note, the functional immaturity of iPSC-derived cells is an important consideration when studying IEM and age-related diseases. As developments in iPSC technology itself progress towards better reproducibility and scalability, we believe that iPSC-based approaches will become a powerful tool for precision medicine, capable of predicting disease trajectories and potential effective treatments at the individual level, not only for IEMs but also applicable to many other diseases.Supplementary file1 (PDF 424 KB)Below is the link to the electronic supplementary material.


Multi-drug resistance (MDR) is a leading cause of cancer-related death, and it continues to be a major barrier to cancer treatment. The tumour microenvironment (TME) has proven to play an essential role in not only cancer progression and metastasis, but also the development of resistance to chemotherapy. Despite the significant advances in the efficacy of anti-cancer therapies, the development of drug resistance remains a major impediment to therapeutic success. This review highlights the interplay between various factors within the TME that collectively initiate or propagate MDR. The key TME-mediated mechanisms of MDR regulation that will be discussed herein include (1) altered metabolic processing and the reactive oxygen species (ROS)-hypoxia inducible factor (HIF) axis; (2) changes in stromal cells; (3) increased cancer cell survival via autophagy and failure of apoptosis; (4) altered drug delivery, uptake, or efflux and (5) the induction of a cancer stem cell (CSC) phenotype. The review also discusses thought-provoking ideas that may assist in overcoming the TME-induced MDR. We conclude that stressors from the TME and exposure to chemotherapeutic agents are strongly linked to the development of MDR in cancer cells. Therefore, there remains a vast area for potential research to further elicit the interplay between factors existing both within and outside the TME. Elucidating the mechanisms within this network is essential for developing new therapeutic strategies that are less prone to failure due to the development of resistance in cancer cells. TP53, causing genetic instability that is known to contribute to tumour progression ..130].Using agents targeting the ECM reduces the density of its components and improves the diffusion of therapeutics ,285,286.It is evident that strategies that target and constrain the tumour stroma might have curative outcomes, especially when the stroma facilitates tumour growth and resistance to therapy. On the contrary, when the stroma performs tumour suppressive functions, such approaches might have undesirable effects . ImportaCancer is a process when too little apoptosis occurs, resulting in tumour growth and MDR. Interestingly, cancer cells are often more sensitive to therapy-induced apoptosis than normal tissues, likely due to oncogenic stress or environmental stimuli such as hypoxia or insufficient nutrition . TherefoYears of research have led to the development of various drugs that target different stages of both intrinsic and extrinsic apoptosis pathways. Generally, two approaches can be employed : (i) stiDue to the pro-survival role of autophagy, agents targeting this pathway have been explored for their application as an anti-cancer therapeutic strategy. However, there are only a few clinically available modulators of autophagy  325,326,328. AmoSeveral approaches for targeting CSCs are currently being investigated. Examples include targeting (i) CSC surface markers, such as CD20 and Cd123; (ii) CSC-associated signalling pathways, such as Wnt, Notch and Hedgehog; (iii) the CSC microenvironment, such as the anti-CXCR4 agent plerixafor and (iv) CSC-directed immunotherapy to checkpoint receptors ,341,342.An interesting approach that has reached clinical trials involves loading CSCs isolated from tumours onto dendritic cells, which are then used as a cancer vaccine . However, targeting CSCs alone is unlikely to be highly effective, given their functional intertwinement with the TME. As discussed, the TME surrounding CSCs creates a niche that supports the survival of CSCs and affects drug sensitivity . Thus, iThe TME consists not only of a heterogeneous population of cancer cells but also a variety of resident and infiltrating host cells, secreted factors and ECM proteins. Here, we have highlighted how tumour progression is profoundly influenced by the close interaction of cancer cells with their TME and how the microenvironmental stress significantly contributes to tumour development and progression. We have also discussed the vital role the TME has in shaping the therapeutic responses and development of drug resistance. Indeed, targeting TME, as well as its components, offers a promising strategy to overcome drug resistance and treat cancer.Overall, conventional anti-cancer drugs promote stress in the TME, which enhances and selects for MDR CSCs. In fact, CSCs have been shown to rapidly develop adaptive mechanisms that allow them to not only survive but thrive within a stressful TME. Thus, the TME stress drives and maintains cancer stemness and promotes an MDR phenotype typical for refractory cancers. We propose that strategies reducing microenvironment stress warrant further research as they might diminish the “ready-to-act” state of the cancer cells/CSCs and paradoxically pre-sensitise them to conventional therapy .


Skin and soft tissue infections (SSTIs) are usually acute conditions of inflammatory microbial occupation of the skin layers and underlying soft tissues. SSTIs are one of the most frequent types of infection, typically requiring medical intervention and contribute to morbidity and mortality in both primary care and hospitalised patients. Due to the dramatic rise of antibiotic resistance, antiseptic agents can be potential alternatives for the prevention and treatment of SSTIs. Notably, they are commonly recommended in many global practical guidelines for use in per- and post- operative procedures. A range of antiseptics, including chlorhexidine, triclosan, alcohol, and povidone-iodine, are used and are mainly formulated as traditional, simple dosage forms such as solutions and semi-solids. However, in recent years, there have been studies reporting the potential for nanotechnology in the delivery of antiseptics. In this review, we have collated the scientific literature that focuses on topical antiseptic formulations for prevention and treatment of SSTIs, and have divided findings into traditional and advanced formulations. We conclude that although nanotechnological formulations have demonstrated potential advantages for delivering drugs; nevertheless, there is still scope for traditional formulations and further development of optimised topical formulations to address the rise of antimicrobial resistance. Skin and soft tissue infections (SSTIs) refer to acute conditions of inflammatory microbial occupation of the skin layers and underlying soft tissues ,2. The cPathophysiology of SSTIs is related to an interruption in the balance between the immune barrier of the host and the pathogenicity of microbial population colonizing human skin . CelluliStaphylococcus aureus (including methicillin-resistant S. aureus/MRSA strains) and beta-hemolytic streptococci .It was reported that there was no serious toxicity caused by a tea tree oil nanoemulsion incorporating silver nanoparticles. TTO NE was prepared by a low energy method using Tween 80 and Span 80 while Ag NPs were prepared using sodium borohydride as a reducing agent and sodium citrate as a stabilizer. This combination demonstrated antibacterial activity against selected microorganisms (from 90 to 95%) at the highest concentration tested (14 μg/mL). Further, blending Ag NPs into a nanoemulsion  (PMMA) nanogels with α-, β-, or γ-cyclodextrin methacrylate (CD-MA). Field-emission-scanning electron microscope (FESEM) images are shown in ironment .Magnetic nanogels containing cobalt iron oxide nanoparticles were developed for the purpose of controlling pH-related release of CHG. It was found that that the magnetic nanogel was pH-responsive and its electroactivity increased at alkaline pH values. In addition, chlorhexidine was most active and was optimally released at pHs from 6 to 7, i.e., when it is ionized. Therefore, it was proposed that these nanogels would be useful for burns treatment as the pH of the environment is higher than normal .E. coli. None of three silver forms caused cell membrane lysis at 1 mg/L Ag [The inhibitory effects on autotrophic and heterotrophic microbial growth by silver nanoparticles (Ag NPs), silver ions and silver chloride colloids were assessed by Choi et al. (2008). According to the results of a short-term existent respirometry appraisal, at 1 mg/L silver, silver nanoparticles had a much greater influence on prohibiting nitrifying microbe growth than other forms. Based on an automatic microtiter appraisal, at silver content of 4.2 µM, Ag ions inhibited completely the growth of  mg/L Ag . Colloid mg/L Ag .The antiseptic efficacy of an oil-in-water emulsion containing nanoparticles of poly-hexamethylene biguanide hydrochloride (PHMB) was found to be more immediate and long-lasting on human skin colonies in comparison with PHMB solutions, with the duration of effect extending up to 150 min .Staphylococcus aureus, which is the key cause of OIAIs [A topical alginate gel (Alg gel)  containiof OIAIs .Nanoparticles containing TCS for the treatment of acne were found to penetrate rapidly into hair follicles and provided a controlled and targeted transport of the antiseptic. Permeation studies found that nanoparticles and emulsions had similar permeation ability albeit lower than a control solution, but retention of TCS in the skin was similar for solution and nanoparticles and highest for emulsion formulations .Solid lipid nanoparticles of triclosan were prepared for topical skin application using glyceryl behenate (GB) and glyceryl palmitostearate (GP) lipids . Solid lCandida albicans than triclosan solution [Another formulation approach to ameliorate issues with the relative hydrophobicity of triclosan was to incorporate branched deblock copolymers as stabilizers in the nanoencapsulation process. Three different amphiphilic branched di-block copolymers were synthesized via the copolymerization of a vinyl monomer  and a covalently cross-linked core. The obtained triclosan nanoparticles presented a sixfold higher antimicrobial efficacy against solution .Polymeric nanoparticles (PNPs) are solid, nanostructures colloidal particles with sizes of 10–100 nm produced using biodegradable polymers such as polylactide-polyglycolide copolymers, and polycaprolactones, or natural polymers, such as gelatine, albumin, and collagen . PNPs arw/w) by an emulsification–diffusion method and were shown to inhibit bacterial growth thus potential applications in the personal care and surgical implant products, drug delivery systems and wound dressing were proposed [Triclosan was encapsulated into poly L-Lactide (PLLA) nanoparticles  containing PVP-I were fabricated using a surfactant-free emulsion copolymerization followed by an iodination procedure. The nanoparticles eliminated 100% of the isolated organisms, including ruginosa  and the Staphylococcus epidermidis [Chlorhexidine base was encapsulated into poly(epsilon-caprolactone) (PCL) nanocapsules. In an ex vivo study, after 8 h incubation, the number of colony forming units (CFUs) from skin treated for 3 min with chlorhexidine nanocapsules was notably lower than that of skin treated with CHG solution. Furthermore, residual chlorhexidine from nanocapsules remaining in the stratum corneum was three-times greater, compared to a solution control. The effective adsorption of PCL nanocapsules on the bacterial membrane is shown in dermidis .T. rubrum which was evidenced through the significant diminution of microorganism count as well as the smallest zones of T. rubrum growth after exposure. Particularly, compared to the nanoemulsion, the tea tree oil nanocapsules were more efficacious against fungi [Nanoemulsions and nanocapsules containing 10 mg/mL TTO were evaluated in two different infectious nail models. Generally, the nanosystems were effective at reducing the growth of st fungi . Furtherst fungi .Nanocapsule formulations have been proposed to address increasing antimicrobial resistance. Triclosan nanocapsules were formulated by interfacial deposition and used chitosan as a coating layer and α-bisabolol as an oily core. Positively charged chitosan was included to optimize interaction with negative charged microorganism membranes and α-bisabolol was selected for its ability to disperse lipophilic drugs such as triclosan. Resultant MICs of nanocapsules coated with chitosan were lower than other formulations and the chitosan-coated nanocapsules were incorporated into wound dressings where they were shown to extend the duration and extent of antimicrobial activity .®, but had potentially wider application due to the elimination of phenoxyethanol from the formulation [A novel formulation comprising phospholipid (Phospholipon90G) and octenidine dihydrochloride was developed as an alternative for phenoxyethanol, which is often added as solubility enhancer for octenidine but may cause irritation, especially on the mucosae and open wounds). According to an antiseptic efficacy test, the lipid-based formulation had a similar inhibitory potency as a marketed product Octaniseptmulation .Liquid crystalline systems (LCS) of glyceryl monooleate (GMO) and water were developed as delivery systems for PHMB and cetylpyridinium chloride (CPC). The authors found that the inclusion of the active drugs into LCS affected the drug release, but not the creation of the liquid crystalline phases. Because of the interaction between CPC and GMO, the drug was trapped in the matrix and not likely to release into the medium, leading to a deleterious impact on bactericidal activity. In contrast, PHMB was released at a constant rate, thus having prolonged antibacterial activity against tested pathogens. In general, the evidence from this study suggests that the liquid crystalline systems can used as a carrier for PHMB .Advanced drug delivery systems have been increasingly investigated for topical administration, primarily applying numerous forms of nano-technology. These formulations demonstrated superior therapeutic activities in prevention and treatment of skin and wound infections, compared to conventional dosage forms. However, they show promising potential in vitro but there is a lack of data on products moving into clinical trials and onto the market.The safety profile and potential toxic effects of nanomaterials is not fully understood and risk/benefit ratio has to be considered . FollowiPotential toxicity of nanocarriers can also be caused by chemical mechanisms due to the production of reactive oxygen species, dissolution and release of toxic ions, disturbance of electron/ion cell membrane transport activity, oxidative damage through catalysis, lipid peroxidation, and surfactant properties. Meanwhile, the nanoparticle size and surface properties of nanoformulations are considered as physical factors result in toxicological effects. They relate to membrane damage and disruption of membrane activity, and can affect transport processes, protein conformation/folding, and protein aggregation/fibrillation . SpecifiFinally, The current review has successfully gathered comprehensive information on various antiseptic formulations employed to prevent and treat skin and soft tissue infections. It is evident from the current review that research in recent years has established topical, mostly dermal, delivery as a promising route. Its ability to bypass the hepatic first-pass metabolism and easy accessibility yet relatively impermeability holds great promise, especially in the treatment of skin infections. This distinctive advantage allows the application of a wide range of external dosage forms that can be easily removed if necessary. These formulations have evolved from simple ointments, creams, and solutions to advanced nanotechnological assisted formulations. However, it is of equal importance that these sophisticated formulations should address clinical and market needs. It is expected that this review will be a helpful resource for formulation scientists to understand and further to develop the antiseptic skin formulations to achieve specific therapeutic objectives.


Sustainment has been defined as the sustained use or delivery of an intervention in practice following cessation of external implementation support. This review aimed to identify and synthesise factors (barriers and facilitators) that influence the sustainment of interventions  in schools and childcare services that address the leading risk factors of chronic disease.Seven electronic databases and relevant reference lists were searched for articles, of any design, published in English, from inception to March 2020. Articles were included if they qualitatively and/or quantitatively reported on school or childcare stakeholders’  perceived barriers or facilitators to the sustainment of interventions addressing poor diet/nutrition, physical inactivity, obesity, tobacco smoking, or harmful alcohol use. Two independent reviewers screened texts, and extracted and coded data guided by the Integrated Sustainability Framework, an existing multi-level sustainability-specific framework that assesses factors of sustainment.n=17, middle n=3, secondary n=4, or a combination n=5) and two in childcare settings. The main health behaviours targeted included physical activity (n=9), diet (n=3), both diet and physical activity (n=15), and smoking (n=4), either independently (n=1) or combined with other health behaviours (n=3). Findings suggest that the majority of the 59 barriers and 74 facilitators identified to impact on intervention sustainment were similar across school and childcare settings. Factors predominantly relating to the ‘inner contextual factors’ of the organisation including: availability of facilities or equipment, continued executive or leadership support present, and team cohesion, support, or teamwork were perceived by stakeholders as influential to intervention sustainment.Of the 13,158 articles identified, 31 articles met the inclusion criteria . Overall, 29 articles were undertaken in schools (elementary Identifying strategies to improve the sustainment of health behaviour interventions in these settings requires a comprehensive understanding of factors that may impede or promote their ongoing delivery. This review identified multi-level factors that can be addressed by strategies to improve the sustainment of such interventions, and suggests how future research might address gaps in the evidence base.CRD42020127869, Jan. 2020.This review was prospectively registered on PROSPERO: The online version contains supplementary material available at 10.1186/s13012-021-01134-y. Contributions to the literaturePrevious studies have documented challenges related to the sustainability of intervention delivery across a range of clinical and community-based settings. This review is the first to identify and synthesise barriers and facilitators influencing sustainment of health behaviour interventions employed in school and childcare settings using a sustainability-specific framework.Barriers and facilitators predominantly relating to ‘inner contextual factors’ of the organisation including: availability of facilities or equipment, continued executive or leadership support present, and team cohesion, support, or teamwork were perceived by stakeholders as most influential to intervention sustainment.These findings contribute to the existing literature regarding the sustainment of evidence-based interventions, and help inform the future development and empirical testing of strategies to address barriers and facilitate the sustainment of health behaviour interventions, supporting positive, long-term health outcomes in children.Globally, chronic diseases are the leading cause of morbidity and mortality, responsible for 70% of all deaths , 2. PoorTo achieve health benefits at the population level, effective interventions targeting these risk factors need to be implemented in an ongoing manner in these settings , 13. RecTwo reviews have reported on the factors influencing sustainment of health behaviour interventions in schools , 21. A 2Similarly, a 2020 review by Herlitz et al.  aimed toBoth reviews provide important contributions to the field; however, they have a few notable limitations. First, although both reviews were published recently, searches were undertaken only up to 2018. Considering the rapid growth in empirical work within the field , it is iFurther evidence synthesis is needed to advance the literature on sustainment of evidence-based interventions. As such, the current review seeks to address the aforementioned limitations of previous reviews. The objective of the current systematic review was to comprehensively identify and synthesise factors (barriers and facilitators) that influence the sustainment of health behaviour interventions in schools and childcare services targeting the leading risk factors for chronic disease development .This review was prospectively registered on PROSPERO  and folArticles reporting on experimental or non-experimental studies of any design that examined factors (barriers or facilitators) qualitatively and/or quantitatively related to the sustainment of a health behaviour intervention  in schools or childcare services were included. Articles were eligible if external support to implement the intervention had ceased at least six months prior to follow-up data collection. External support included the provision of training, funding, or resources and other implementation support by researchers or agencies tasked with implementing the health behaviour intervention.Articles of studies that conducted interventions in schools  or childcare services  were included. Eligible participants were considered any end-user or stakeholder who may have been involved in the sustainment of an intervention in schools or childcare services. This included teachers, principals, service managers, or other relevant staff, as well as administrators or officials of other government or non-government agencies that regulate, encourage, or enforce health behaviour interventions in schools or childcare services. We did not include families and/or caregivers as participants.Articles targeting the sustainment of an intervention that addressed the following health behaviours in schools and childcare services: poor diet, physical inactivity, obesity, tobacco smoking, and harmful alcohol use were included.Perceived factors (barriers and facilitators) that were reported to influence the sustainment of a health behaviour intervention addressing poor diet, physical inactivity, obesity, tobacco smoking, and harmful alcohol use in schools or childcare services were included. Measures of sustained behavioural effects on an individual child’s behaviour  were not included in this review. Consistent with other reviews , a barriA systematic review of eight databases , MEDLINE, EMBASE, PsycINFO, ERIC, CINAHL, and SCOPUS) was conducted by an experienced librarian (DB) in March 2020. There was no date limit set. The search strategy  unblinded to author or journal information. Full text screening of manuscripts was also screened in duplication by four review authors , and reasons for exclusion were recorded. Screening of articles was conducted using the Covidence systematic review software . DiscrepData extraction from the included articles was conducted independently by authors AS and HB. Data extraction sheets were prepared  using the Mixed-Methods Appraisal Tool (MMAT) . The MMABarriers and facilitators reported to be important for sustainment were coded using the Integrated Sustainability Framework, a theoretically informed framework covering the unique and multidimensional factors related to longer-term intervention delivery following implementation support  across a range of clinical and community-based settings (including schools and childcare services) . This frThe article selection and screening process is outlined in Fig. n=19)  [n = 8 articles). A specific example included training/professional development opportunities to upskill. The most frequently identified characteristic of the interventionists and population was ‘population characteristics’ (n = 11 articles). A specific example included community/parental support/engagement. Lastly, the most frequently reported characteristic of the intervention was ‘perceived benefits’ (n = 9 articles). A specific example included programme flexibility/variety.Twenty-five articles , external ongoing funding, and communication between schools and external programme organisers and/or funders  were also frequently identified as influential to intervention sustainment. Whilst some external barriers and facilitators were identified in previous reviews , 21, we Findings across school and childcare settings suggest barriers and facilitators relating to ‘inner contextual factors’ including availability of space/facilities/equipment , executive/leadership support present, and staff turnover/attrition were particularly important to intervention sustainment. Additionally, barriers and facilitators relating to ‘implementer characteristics’ responsible for delivering the intervention including staff motivation and ‘intervention characteristics’ such as programme flexibility and cost-effectiveness were important for intervention sustainment. Similarities in identified factors across settings suggest that future efforts to address these factors could potentially be generalised across schools and childcare services. However, to our knowledge no studies have developed strategies to support the sustainment of interventions in childcare services. Given organisational differences in setting between schools and childcare services and the notably limited research conducted in childcare services as opposed to schools in this area, it is difficult to hypothesise strategies to facilitate intervention sustainment across these settings. However based on the current evidence and theory, the followings strategies may be of particular use: (1) promoting strong, continuous executive/administrative and staff engagement/support; (2) facilitating the provision of relevant resources and programme materials/equipment, to support the sustained delivery of interventions within schools and childcare services. Given there are very few empirical studies that have assessed the effectiveness of such strategies particularly in childcare services , we recoThe findings of this review should be considered in the context of its methodological limitations. First, only articles published in English were included; thus, other relevant articles arising from other non-English speaking countries may have been missed. Second, studies were undertaken in schools and childcare services from diverse geographical regions , with populations of varying SES and race/ethnicity; however, they were predominantly conducted in higher income countries; therefore, the extent to which these findings are generalisable to other countries is limited. Thirdly, when assessing the methodological quality of included articles, the sample representativeness of the target population and low risk of non-response bias were consistently of low quality for most included quantitative and mixed method articles, which may potentially impact on both the generalisability and validity of the results.This review comprehensively identifies and synthesises the factors related to the sustainment of health behaviour interventions in schools and centre-based childcare services using a sustainability-specific framework. Intervention sustainment in schools was predominantly dependent on their organisational readiness and resources, as well as organisational leadership and support available. These findings build on the existing literature regarding the sustainment of evidence-based interventions in schools and childcare services. Finally, these results help inform the future planning, development, and empirical testing of strategies to address barriers and facilitate the sustainment of health behaviour interventions, supporting positive, long-term health outcomes in children.Additional file 1: PRISMA guidelines for reporting.Additional file 2: Search strategy and terms for each database.Additional file 3: Data extraction and assessment form template.Additional file 4: Quality appraisal form.Additional file 5: Qualitative participant descriptions of barriers and facilitators identified.Additional file 6: Comprehensive list of barriers and facilitators identified.Additional file 7: Quality appraisal ratings.


Ferroptosis is a newly identified form of regulated cell death that is associated with iron metabolism and oxidative stress. As a physiological mechanism, ferroptosis selectively removes cancer cells by regulating the expression of vital chemical molecules. Current findings on regulation of ferroptosis have largely focused on the function of non-coding RNAs (ncRNAs), especially microRNAs (miRNAs), in mediating ferroptotic cell death, while the sponging effect of circular RNAs (circRNAs) has not been widely studied. In this review, we discuss the molecular regulation of ferroptosis and highlight the value of circRNAs in controlling ferroptosis and carcinogenesis. Herein, we deliberate future role of this emerging form of regulated cell death in cancer therapeutics and predict the progression and prognosis of oncogenesis in future clinical therapy. Cell death is an irreversible mechanism that is associated with metabolism of the internal environment within the eukaryon in order to maintain cellular homeostasis and development in mammals. Recently, ferroptosis has been identified as a type of non-apoptotic cell death , leadingNon-coding RNAs (ncRNAs) used to be considered junk molecules, but have recently incite considerable interest and new insights  due to tFerroptosis refers to a novel form of non-apoptotic cell death. The hallmarks of ferroptosis progression include lipid peroxidation, iron dependence, and inhibition of GPX4-dependent antioxidative systems, leading to a lethal accumulation of lipid reactive oxygen species (ROS), which eventually leads to cell death. On the contrary, iron chelators, antioxidative enzymes, and depletion of polyunsaturated fatty acids (PUFAs) prevents cells from ferroptosis. Additionally, accumulation of lethal lipid ROS has a significant function in numerous diseases, including tumorigenesis, neurological diseases, ischemia reperfusion injury (IRI), renal failure, and hematological system diseases. Emerging evidence has demonstrated that the accumulation of iron in pathological regions is a symptom of specific degenerative diseases . MoreoveThe initiation and execution of ferroptosis relies on the intersection of amino acid, lipid and iron metabolism . In otheCystine is a disulfide congener of cysteine. Cystine import is driven by system Xc-  with gluGlutamine (Gln), a non-essential amino acid, is the most abundant amino acid within the circulatory system of human body. Sufficient cellular Gln is crucial for compensation of GSH, which further enhances the scavenging efficacy to attenuate cellular damage caused by ferroptosis. GPX4 is an essential enzyme that enhances the ferroptosis resistance by transforming lipid hydroperoxides (L-OOH) into the alcohol forms (L-OH), and further maintain cellular redox equilibrium. Besides, nuclear factor erythroid 2-related factor 2 (Nrf2), another pivotal enzyme involved in the cellular antioxidative system, has a positive effect on GSH metabolism by upregulating the radical-scavenging enzyme γ-glutamyl cysteine synthetase (γ-GCS)  and mediferritinophagy, during which the labile iron pool can be enriched by degrading mitochondrial heme and ferritins (2+-independent phospholipase A2β (iPLA2β) can attenuate ferroptosis by hydrolyzing cellular peroxidized phospholipids  has combined with transferrin, the transferrin receptor 1 (TfR1), a transmembrane glycoprotein, will internalize this complex and release it into the cytoplasm. The transferrin-bound iron will be stored into a non-toxic form inside ferritins. The process of ferritin’s sequestration and degradation is termed as erritins . Ferropoerritins . ROS, a holipids .The sensitivity of neoplastic diseases to ferroptosis is highly valued for underlying therapeutic strategies. Ferroptosis may serve as an inhibitory factor for carcinogenesis as neoplastic cells are vulnerable to increased levels of Fe (II) and cellular lipid peroxides . Convers1S,3R-RSL3), ML162 (DPI7), and ML210 (DPI10) are able to inactivate GPX4 bioactivity and enhance resistance to lipid peroxidation during carcinogenesis  . In addiogenesis .ferroptosis-inducing agents (FIN), several conventional chemotherapeutic drugs , the mutant gene TP533KR is able to induce ferroptosis and suppress tumor growth by inhibiting SLC7A11 and activating ALOX12 expression  accumulation by inactivating the Nrf2-targeted genes HO-1 and FTH11 (Ras can cause activation of Ras proteins and ultimately execute cancer progression. Studies on Ras-mitogen-activated protein kinase (MEK) suggests that upregulation of this oncogenic pathway is able to enhance the sensitivity of cancer cells to ferroptosis by exacerbating lipid peroxidation and generating excess ROS  and in mammals as lethal 7 (let-7), ncRNAs have been shown to participate in regulating gene expression (Non-coding RNAs (ncRNAs) refer to RNAs that are transcribed that do not encoding proteins. Since small temporal RNAs were initially discovered in pression . The ncRpression .Among ncRNAs, microRNAs (miRNAs) are the most intensively studied ncRNAs in the modulation of carcinogenesis. MiRNAs are endogenous small RNAs, between 21 and 24 nucleotides long, and can be transferred from cell-to-cell by several ways  to alter genetic or epigenetic phenotypes of cancer . MiRNAs With the explanation of miRNA efficacy in cancer treatment, more attention has been paid to ncRNAs in order to investigate whether other ncRNAs, such as circRNAs, have similar bioactivity as miRNAs in order to modulate the carcinogenic processes. Moreover, several reports have assessed the potential effectiveness of circRNAs to repress the miRNA-mediated mRNA editing via absorbing tumorigenic regulators as miRNA-sponges . NotablyTaken together, based on current biofunctions of ncRNAs in cancer growth, this review has focused on exerting these molecular regulators in ferroptosis and pay greater attention to the promising efficacy of circRNAs, which has not been reported until now.Recently, ncRNAs have become increasingly recognized as playing a significant role in mediating the development of cancer . LncRNAsNotably, miRNAs are significantly involved in regulating ferroptosis among cancer cells . In melaGSH homeostasis is known to be a key factor of oncogenesis. Recent studies have highlighted the function of specific miRNAs in modulating intracellular GSH levels. For example, miR-4715-3p is inhibited by overexpression of AURKA (aurora kinase A), a serine threonine kinase that has a significant role in mitotic progression in both normal cells and cancers . ReconstAs mentioned previously, SLC7A11 is an important factor that protects cells against ferroptosis due to the antioxidative efficacy enhanced by cystine uptake for cellular GSH metabolism. In oral squamous cell carcinoma (OSCC), miR-375 acts as a tumor suppressor by inhibiting SLC7A11 expression, leading to ferroptosis . SimilarELAVL1. Studies have revealed a role for LINC00336 as a competing endogenous RNA (ceRNA) to inactivate miR-6852 in lung cancer, thus allowing it to be potential target of lung cancer therapy. To date, limited studies have evaluated the interaction between lincRNAs and ferroptosis. However, studies have shown that, similar to miRNAs, lincRNAs can act as dual regulators for ferroptosis, either by absorbing certain miRNAs to alter their effects or combining with certain enzymes to have an effect on the bioactivity of cancer cells , which are cyclized from exon, circular intronic RNA (ciRNA) from introns and exonic-intronic circRNA (EIcircRNA) . CircRNAin situ hybridization, high-throughput sequencing) that are mature enough for circRNA profiles. CircRNAs are reported to abnormally express in many cancers, such as hepatocellular carcinoma   . Moreove(ALKBH5) . As circ(ALKBH5) , we assuCircRNAs provide a promising value in the treatment of MDR of cancers, particularly when targeting the relationship between circRNAs and ferroptosis. Accordingly, ferroptosis has paved the way to develop gene-oriented strategies and more precisive gene therapies than conventional anticancer drugs. Based on previous evidence, we can assume that certain circRNAs likely act as miRNA sponges in order to inhibit modulation of downstream transcription in cancer cells, and guide the probable direction of elucidating the underlying features of circRNAs in classical ferroptosis or tumorigenic mechanisms. Furthermore, circRNAs can exert advantages of molecular construction, which directly affects upstream transcriptions. CircRNAs are able to be translated into proteins, which suggests that applications of their expression as regulators can disturb upstream genes. Nevertheless, many controversial views have emerged in circRNAs research and application. As only a limited number of circRNAs have been reported as miRNA sponges, while others only have few miRNA binding sites , are theIn brief, there is a considerable value of bioactivity among circRNAs which can contribute to further studies in ferroptosis progression and oncogenic regulation, despite the fact that the relationship between ferroptosis and circRNAs requires more identification.erastin indicate that these ferroptosis inducers likely have multiple targets in regulating ferroptosis mechanisms and influence the expression of ncRNAs, such as miRNAs. Importantly, with the exception of the canonical anticancer drugs, several non-neoplastic drugs have been identified as exerting their capacity to promote the ferroptosis process and transcriptional regulation in cancer cells. Intriguingly, artemisinin and its derivatives have shown enhanced anticancer values synergizing with classical antitumor drugs. These findings contribute to identifying viable pharmacological therapies in cancer treatment. Thus, ferroptosis is likely regarded as an effective clinical strategy in order to avoid chemo-resistance in anticancer treatment.In conclusion, ferroptosis not only helps maintain a dynamic equilibrium under physiologic conditions, but also acts as an effective biomechanism to hinder tumorigenic progression in cancer therapies. The efficacy of tumor suppression is executed by dysregulating cystine uptake, glutathione metabolism and redox homeostasis. Mediating ferroptosis may help provide specific molecular targets for suppressing oncogenesis, and can be used in estimating prognosis of neoplastic diseases. As more ferroptosis inducers have been identified, several compounds have emerged as key factors to protect organisms from malignant tumors by exacerbating cell death at the translational level. Moreover, studies of Numerous studies have recognized miRNAs as being able to modulate oncogenes and genes involved in ferroptosis. miRNAs provide potential gene therapy of cancer treatment by intentionally promoting exacerbation of ferroptosis and dysfunction of oncogenic expression at the transcriptional level. It has been reported that the interaction between miRNAs and anticancer drugs has diverse effects on oncogenesis. Some miRNAs  are able to enhance resistance to cisplatin by inhibiting ferroptosis , while oIn summary, although regulatory ncRNA, especially circRNAs, are complex and interactions with ferroptosis will require considerable work to unravel, circRNAs can be considered dependable diagnostic and therapeutic molecular biomarkers for cancer in manipulation of cell death. They also facilitate the development of chemoresistance to anticancer drugs and provide a genetic approach for better diagnosis, predicting prognosis and treatment response to cancer.KQZ and YZ had the idea for the article. BSW, LG, and WHR collected the references, performed the literature search, and data analysis. YZ and KXL drafted the first manuscript and prepared the figures and tables. KQZ and KXL designed and corrected the final manuscript. All authors contributed to the study conception and design and read and approved the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


On the other hand, preclinical animal models are extremely costly and present problems of inaccuracy due to species differences. To address these limitations, tissue chips offer the opportunity to emulate physiological and pathological tissue processes in a biomimetic in vitro platform. Tissue chips enable in vitro modeling of CVDs to give mechanistic insights, and they can also be a powerful approach for drug screening applications. Here, we review recent advances in CVD modeling using tissue chips and their applications in drug screening.In recent years, the cost of drug discovery and development have been progressively increasing, but the number of drugs approved for treatment of cardiovascular diseases (CVDs) has been limited. Current  Following these in vitro assays, drug candidates undergo further cardiotoxicity testing in vivo before entering clinical trials. Even with stringent preclinical testing, cardiotoxicity remains the second most common reason for drug recall from market, behind hepatic toxicity (Cardiovascular disease (CVD) is the leading cause of death worldwide . In the toxicity . Taken tin vitro cardiotoxicity and drug screening efforts that use overly simplified in vitro platforms, cardiovascular tissue chips are micro-to-miniature culture systems that intend to better mimic the complex structure and function of the myocardium or vasculature. The tissue chips incorporate features such as three-dimensionality, multi-cellular interactions, tissue perfusion, hemodynamic shear stress, pulsatile flow, and cyclic stretch to better resemble the native environment. Additionally, the use of primary human cells or specific induced pluripotent stem cell derivatives into cardiovascular tissue chips enable more precise testing of patient-specific responses. Accordingly, cardiovascular tissue chips can complement the current developmental pipeline for drug discovery. In this focused review, we will describe the various strategies by which cardiovascular tissue chips have been developed for disease modeling or drug screening applications, and then discuss emerging areas in this field.To address the limitation of existing -cellular interactions, three dimensionality, and mechanical cues. Techniques for fabricating cardiovascular tissue chips, such as photolithography, micromolding, and three dimensional (3D) bioprinting are described in detail elsewhere  and smooth muscle cells (SMC) can be expanded in vitro, primary human cells have limited doubling times. As an alternative cell source for tissue chips, human induced pluripotent stem cells (iPSC) are ideal because they are a theoretically infinite source of cardiovascular cells. When coupled with robust differentiation methods for CMs and vascular lineages (Cardiomyocytes (CMs), the contractile cells of the myocardium, are generally considered to be non-proliferative in the post-natal state and cannot be expanded lineages , the abilineages . Howeverlineages . To addrlineages  or spatilineages  have beeThe myocardium consists of several different cell types, including CMs, ECs, fibroblasts, and pacemaker cells . Blood vt-tubules and z-disks, compared to cells in two-dimensional (2D) monolayers  for 6 h to model MI, whereby nutrients were also depleted from the culture media (2). This method showed distinct differences by the increased cell death during ischemia and mitochondrial membrane permeability during reperfusion. Another approach to model MI utilizes oxygen diffusion gradient through spherical cardiac organoids (300 μm diameter) were cultured under hypoxic condition (10% O2) for 10 days to mimic clinically relevant hallmarks of a post-MI heart: infarcted, border, and remote zones  and reperfusion injury that often follows is the most common morbidity amongst CVDs . Using tre media . Then tote zones . MoleculHeart failure is one of the most prominent CVDs  with limMost cardiac tissue chips focus on the ventricular function as it is the most common mode of heart failure associated with reduced ejection fraction. However, it is also important to consider effects on atrial functions for disease modeling, especially in the context of arrhythmia. One group produced a cardiac tissue with both atrial and ventricular on the ends of a cardiac tissue using the Biowire II platform . This meVascular component of the cardiovascular system consists of arteries and veins to transport blood and nutrients to the body. Endothelial dysfunction is known to be the first stages of atherosclerosis, the most common CVD . ECs regIn addition, vascular chips are also useful for modeling aspects of atherosclerosis. Tissue engineered blood vessels  were fabricated in a perfusion system to model early-stage atherosclerosis . The sizThrombosis is commonly associated with atherosclerosis, MI, and stroke . ThromboThree dimensional printing technology allows for further freedom and greater control to mimic 3D architecture of blood vessels. Tissue chips have also been employed to examine the function of ECs from diseased settings. Blood outgrowth ECs from healthy or type 1 diabetic pigs and used to endothelialize microchannels in a single-channel vascular chip . MicrovePreclinical screening of a drug’s thrombogenicity remains to be an unmet need given the complex and multifactorial process of thrombosis. Utilizing a vessel chip, 5 CMs in 50 replicates (4 CMs per sample) used in the Biowire II 3D cardiac constructs (An emerging direction of tissue chips is the down scaling of the technology to enable higher throughput analysis, while maintaining its superiority over conventional 2D cell culture assays. For example, muscle thin films were generated using 4 × 10plicates , which instructs . While mAnother emerging direction is the automation of data collection and analysis. Recent advances in tissue chip designs have led to the incorporation of sensors or imaging capabilities to increase throughput. Micro-cracked titanium gold thin films were incorporated into the muscle thin films as a flexible strain sensor to measure contractile force . This imIn conclusion, cardiovascular tissue chips have been shown to be useful in modeling cardiac and vascular diseases, as well as in providing a physiologically relevant platform for drug screening. However, in the design of tissue chips, the balance between physiological fidelity and efficiency should be considered. Tissue chips that mimic multiple aspects of physiological or pathological states often entail complex designs, but complexity can adversely affect a tissue chip’s scalability and adaptation to high-throughput systems. Therefore, this balance between complexity and scalability should be thoughtfully considered in the design of tissue chips.Despite recent advances, tissue chips have not yet become the “gold standard” platform for CVD drug screening. Looking forward, patient-specific cells for personalized disease modeling will become increasingly more prevalent. Conversely, drug screens will utilize genetically diverse patient-derived cells to increase the confidence in the efficacy of a drug candidate. Although iPSC-derived CMs from patients with dilated cardiomyopathy , long QTNH and AC performed literature analysis, analyzed the data, and interpreted the data. AC wrote the manuscript, with editorial feedback by NH. Both authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Excess epicardial adiposity, within a state of obesity and metabolic syndrome, is emerging as an important risk factor for the development of cardiovascular diseases (CVDs). Accordingly, increased epicardial fat thickness (EFT) implicates the exacerbation of pathological mechanisms involving oxidative stress and inflammation within the heart, which may accelerate the development of CVDs. This explains increased interest in targeting EFT reduction to attenuate the detrimental effects of oxidative stress and inflammation within the setting of metabolic syndrome. Here, we critically discuss clinical and preclinical evidence on the impact of physical exercise on EFT in correlation with reduced CVD risk within a setting of metabolic disease. This review also brings a unique perspective on the implications of oxidative stress and inflammation as major pathological consequences that link increased EFT to accelerated CVD risk in conditions of metabolic disease. Epicardial adipose tissue (EAT), due to its close proximity to the heart, is known to affect the cardiovascular system by releasing excess lipids such as low-density lipoproteins (LDL), as well as adipokines such as interleukin (IL)-6 that can elicit an undesired pro-inflammatory response, subsequently prompting atherosclerosis and vascular endothelial dysfunction ,2,3. In More review articles published in 2020  and earlEAT is considered a visceral fat depot that surrounds 80% of the heart’s surface . The mul2-max) and exercise capacity in patients with preserved ejection fraction heart failure. Similarly, Haykowsky et al. [Briefly, in patients with established coronary microvascular dysfunction, Sengul et al.  found thy et al.  reportedUnderstanding how EAT expansion during obesity or in patients with metabolic disease is related to increased CVD risk  in reducing EFT, subsequently influencing markers that are essential in determining cardiac function . For exaClinical evidence presented in 2-max and flow-mediated dilation in postmenopausal women with high CVD risk. Zhang et al. [Additional clinical studies have also reported on the positive effects of the long-term effects of physical exercise on the reduction of EFT in patients with heart failure or diagnosed with CVDs . Jo et ag et al.  revealedg et al. ,76. Markg et al. ,78. Exerg et al. . Taken tg et al. . HoweverNon-communicable diseases, especially metabolic syndrome, contribute significantly to the rising global disease burden . IncreasAlthough currently used therapeutic drugs such as metformin and statins can effectively reduce blood glucose or lipid levels to prolong the lives of patients with metabolic syndrome, the long-term use of these drugs has been associated with several limitations including toxicity, ultimately leading to increased CVD risk ,87,88. CSimilar to weight gain, it is currently understood that EFT can be exacerbated by several modifiable risk factors such as a sedentary lifestyle, stress, and an unbalanced diet ,85. StudIn conclusion, evidence from the current review supports the regular use of physical activity or exercise to alleviate complications linked with the progression of metabolic diseases, including reducing EFT, to attenuate the detrimental effects of oxidative stress and inflammation in those at risk of developing cardiovascular complications. Notably, while such beneficial effects of physical exercise are acknowledged, few individuals adhere to these interventions. Thus, research into novel therapies that could target EFT to improve cardiac function is still required.


Repairing the human brain remains a challenge, despite the advances in the knowledge of inflammatory response to injuries and the discovery of adult neurogenesis. After brain injury, the hostile microenvironment and the lack of structural support for neural cell repopulation, anchoring, and synapse formation reduce successful repair chances. In the past decade, we witnessed the rise of studies regarding bioscaffolds’ use as support for neuro repair. A variety of natural and synthetic materials is available and have been used to replace damaged tissue. Bioscaffolds can assume different shapes and may or may not carry a diversity of content, such as stem cells, growth factors, exosomes, and si/miRNA that promote specific therapeutic effects and stimulate brain repair. The use of these external bioscaffolds and the creation of cell platforms provide the basis for tissue engineering. More recently, researchers were able to engineer brain organoids, neural networks, and even 3D printed neural tissue. The challenge in neural tissue engineering remains in the fabrication of scaffolds with precisely controlled topography and biochemical cues capable of directing and controlling neuronal cell fate. The purpose of this review is to highlight the existing research in the growing field of bioscaffolds’ development and neural tissue engineering. Moreover, this review also draws attention to emerging possibilities and prospects in this field. in vitro or be used as stem cell delivery route in a brain injury . Bioscaffolds can also contain si/miRNAs that will modify locally neural cells gene expression  or contain exosomes/growth factors for paracrine signaling such as stimulating neurogenesis and increase neural stem migration to injury area . This cover has been designed using resources created by Vitaly Gorbachev from Flaticon.com.Bioscaffolds potential applications in tissue engineering. Bioscaffolds can be used to grow stem cells and target their differentiation  Brain injuries are a significant cause of mortality and morbidity across the world. Injuries are divided into two types: (i) traumatic brain injury (TBI), caused by an external force to the head, such as a bump, blow, or penetrating object, and (ii) injury associated with a neurologic illness or condition, such as stroke, brain cancer, and other neurogenerative diseases . In 2016Inflammation is a complex biological process in the body in response to cell and tissue damage . The defThere are several possible mechanisms of inflaming. Here, we provide a general overview of the process. The inflammatory processes may be initiated by the endogenous host-derived cell debris [damage-associated molecular patterns (DAMPs)] originated from acute cell death or that accumulate with age due to increased production or impaired elimination . DAMPs bThe inflammatory response stop mechanism is called “inflammation resolution.” Inflammation resolution naturally occurs after acute or chronic inflammation and relies on the synthesis of specialized pro-resolving lipid mediators (SPM) by endothelial cells, macrophages, and neutrophils . SPM areAfter an injury, the presence of ROS, free radicals, and pro-inflammatory cytokines makes the perilesional area a hostile environment for cell survival . ReactivAstrocytes are well known for providing neuron trophic support. In the injury site, astrocytes maintain that function, producing and secreting several metabolites, including glucose, nutrients, and growth factors such as insulin-like growth factors (IGFs), nerve growth factors (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 . Thus, aBrain plasticity refers to any process that leads to the recreation of functional neuronal circuits and function regain. Plasticity involves short-distance axon sprouting, leading to new connections and alteration in the strength of existing connections . These cin vitro  of the hippocampus dentate gyrus, in which newborn neurons migrate laterally and integrate the hippocampus’s granular zone, and the subventricular (SVZ) located in both lateral ventricles. Neural stem cells (NSC) located in the SVZ are pluripotent stem cells (iPSC) that can differentiate into astrocytes, oligodendrocytes, and neurons. Newborn neurons (neuroblasts) from the SVZ migrate a long distance through the rostral migratory stream (RMS) to the olfactory bulbs, where they differentiate into mature interneurons . The disin vivo, neuroblasts migrated around the glial scar and attributed the inhibition of penetration into the scar to the presence of CSPG. In vitro, CSPG impaired neuroblast migration by altering cell protrusion and adhesion dynamics through Rho GTPase inhibition.The glial scar matrix components also influence NSC cells under both physiological and pathological conditions. The developing CNS is enriched in proteoglycans which control developmental processes: neuronal migration and homing. In the adult brain, CSPG contributes to the maintenance of the neurogenic niches. Sulfated proteoglycan structures and, especially CSPG, were reported to affect NSC fate, survival, and maturation . In a moAlthough mobilization of NSC toward the injury occurs, many cells die or stray from the migratory path. Many NSC that reach the injury area fail to integrate into new neuronal circuits and die. For this reason, adult endogenous neurogenesis is insufficient for complete brain repair .To answer this question, we must first address the concept of repair. The term “repair,” when used to describe damaged tissue healing, means to restore tissue architecture and function and comprises two processes: regeneration and replacement. Regeneration occurs when the damaged tissue grows into new tissue and is restored to its normal state. Replacement occurs when a different tissue, usually connective tissue, is deposited over the damaged tissue, producing a scar . The CNSAs with most tissues in the body, the brain has mechanisms to regenerate itself, such as, previously mentioned, endogenous neurogenesis and neuroplasticity . Howeverin vivo tissues and organs . The material should induce no or minimal inflammatory response. In this way, once long-term implants can cause a chronic inflammatory reaction, degradability is also desirable, and degradation products should be non-cytotoxic as well. Once the brain is confined to the skull, the biomaterial must present minimal swelling to avoid a rise in intracranial pressure .The presence of a rigid skull also influences the biomaterial delivery route, making injectable and shape-adaptable materials like hydrogels preferred over solid scaffolds that require invasive surgical procedures for the implant .de novo tissue formation and less prone to generating an immune response. However, its physicochemical properties are difficult to control , the brain biophysical environment (viscoelastic properties and porosity), the ECM three-dimensional (3D) architecture on a biologically relevant length scale, and stimulate cell infiltration into it .Bioscaffolds’ mechanical forces can regulate the cell biological environment and control how cells interact with each other and with the ECM .in vitro. There is a lack of in vivo data, which explains the absence of commercially available human therapy platforms so far. One of the concerns regarding implanting biomaterials in the brain is the foreign body response  cells neurite outgrowth and protected PC12 and HEK293 (human embryonic kidney) cells against formaldehyde acid treatment. Right L5/6 spinal nerve ligation was performed in Sprague-Dawley rats to induce mechanical allodynia and thermal hyperalgesia. Exosomes in scaffolds were wrapped around ligated L5/6 spinal nerves for treatment. Treated rats performed better in functional scores and presented signs of enhanced myelinization of injured axons. Treatment also attenuated upregulation of c-Fos, GFAP, Iba1 , TNFα, and IL-1β, while enhancing IL-10 and GDNF  in the ipsilateral dorsal root ganglion.3 layered double hydroxide as a non-viral vector to deliver nucleic acids  to MSC using a 3D scaffold approach. Nucleic acids were complexed with MgAl-NO3 layered double hydroxide and incorporated in collagen-nanohydroxyapatite scaffolds. The fabricated platform allowed successful MSC transfection.Gene therapy is fast-growing, and many CNS disorders are potential candidates for treatment approaches that involve the correction of genetic abnormalities . HoweverThe bioscaffold-gene therapy combination strategy has been investigated for the development of angiogenic platforms. Angiogenesis is a critical process required in the regeneration of many tissue and systems, including CNS regeneration . Laiva eHuntington’s Disease (HD) is an inherited autosomal-dominant neurodegenerative disease. Although genetic mutation responsible for HD is well know, there is still no treatment to stop or slow disease progression. Microtissue engineered neural networks (micro-TENNs) were developed at the University of Pennsylvania for supporting neuronal survival and neurite extension . Micro-TMicro-TENNs were injected into rats’ brains using a stereotaxic device to connect deep thalamic structures with the cerebral cortex. The authors found that micro-TENN neurons survived at least 1 month and maintained their extended axonal architecture along the cortical-thalamic axis. They also found micro-TENN neurons extend neurites into the host cortex, with successful synapse formation . In anotin vitro miniature organ resembling the brain. Organoids production relies on self-organizing cell properties, recapitulating early developmental events , LMX1B (LIM homeobox transcription factor 1-beta), TH, and PAX6 (Paired box protein 6) after 30 days.Although implantable brain tissue is not yet available, it is feasible to produce smaller and less complex brain structures to study physiological cell-to-cell or cell-to-material interactions. 3D bioprinting can improve Although spontaneous tissue regeneration is limited in the CNS, tissue engineering strategies to overcome the biological and physical challenges imposed by brain injury are gradually being developed.Bioengineering already offers a series of commercially available products for tissues like skin, bone, and cartilage, but this is not the case for the CNS, and up to now, there are no suitable bioengineered therapeutic solutions to amend injuries to the CNS.This review highlighted the CNS therapeutic approaches involving bioscaffolds. Since several pathologies can affect the CNS, it is rational to believe that these approaches will be complementary rather than competing, and the constructs should match patient needs. In PD, for example, a platform that stimulates dopaminergic neuron differentiation is required, whereas, in amyotrophic lateral sclerosis (ALS), the challenge is to replace long neuronal tracts. The advancement of precision medicine and new scaffold fabrication methods such as 3D printing will allow individualized treatment. Bioscaffolds and scaffold-based constructs should evolve in the next years with increasing complexity and functionality, impacting medical research.However, significant challenges must be addressed. It is still impossible to produce fully vascularized tissue units, which is essential to increase constructs’ thickness and complexity while ensuring cell survival. Also, biomaterials’ long-term effects in the CNS and their interaction with the immune system must be addressed. Finally, it is essential to understand developmental biology to better design “smart bioscaffolds” capable of stimulating neurogenesis and neural network formation.LZ and MM wrote the manuscript. MP revised and approved the manuscript. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The complex composition of bacterial membranes has a significant impact on the understanding of pathogen function and their development towards antibiotic resistance. In addition to the inherent complexity and biosafety risks of studying biological pathogen membranes, the continual rise of antibiotic resistance and its significant economical and clinical consequences has motivated the development of numerous in vitro model membrane systems with tuneable compositions, geometries, and sizes. Approaches discussed in this review include liposomes, solid-supported bilayers, and computational simulations which have been used to explore various processes including drug-membrane interactions, lipid-protein interactions, host–pathogen interactions, and structure-induced bacterial pathogenesis. The advantages, limitations, and applicable analytical tools of all architectures are summarised with a perspective for future research efforts in architectural improvement and elucidation of resistance development strategies and membrane-targeting antibiotic mechanisms.The online version contains supplementary material available at 10.1007/s12551-021-00913-7. All organisms rely on the presence of biological membranes acting as barriers between the inside and outside cellular environments. The functionality of such membranes is dictated by the types of lipids and other molecules that make up their often highly complex structure Watson .The “ESKAPE” pathogens, a faction of Gram-negative (GN) and Gram-positive (GP) bacteria, are responsible for the majority of nosocomial infections and are deemed a great threat to global healthcare because of their multidrug resistance (MDR) , which typically penetrate the cell membrane to facilitate cellular entry of medication, or directly disrupt the cell membranes structural integrity to facilitate cell lysis  have been found to allow GN bacterial pathogens to evade host-immune attack, increase pathogenesis, and develop antimicrobial resistance  wall Fig.  Kapoor . The inndlt operon and/or incorporation of L-lysine in PG via the mprF gene can lead to an enhanced resistance against cationic antimicrobials , or synthetic lipids determined by the user (< 3 lipid species) asymmetrically arranged in a bilayer. Liposome formation using bacterial lipid extracts provide a more biologically attune system as various lipid species and their native molecular variants are inherently incorporated. Under an artificially user-defined composition, the inner and outer leaflets for GP liposome models commonly contain PG, lysyl-PG, and CL, whilst GN liposome models commonly contain PE, PG, and CL and uncommonly LPS. Liposome models have been utilised to investigate basic structural  and rheological  membrane properties. In addition, protein and peptide-lipid interactions  consist of a lipid bilayer that is placed onto a solid substrate either via direct contact, via separation by a polymer cushion, or allowed to float directly above a covalently-bound self-assembled monolayer or a supported bilayer Fig.  Anderss. TethereGold is the most commonly utilised substrate material for sBLMs and tBLMs due to its stability, facile functionalisation, and versatility in surface analysis techniques  of synthetic lipid species; however, they can also contain bacterial lipid extracts (> 4 lipid species) asymmetrically arranged in a bilayer. Unlike user-defined systems which are limited to the number and type of lipid species and their associated molecular variations incorporated, architectures formed from bacterial lipid extracts generate increasingly accurate biological models as various lipid species and their native molecular variants are inherently incorporated. Under user-defined compositions, the inner and outer leaflets of architectures modelling GN and GP bacteria commonly contain one molecular variation of PC. Few architectures have been developed where the inner and outer leaflets contain the most common lipid species or analogues thereof for GN  and GP  bacteria. For sBLM and tBLM systems, lysyl-PG is often substituted with DOTAP as it is more affordable for the increased quantities required to generate the architectures  and docosahexaenoic acid (DHA)  and/or a mixture of PE, PG and sometimes CL. To compensate for the significant variation in the constituents of the phospholipids and LPS between bacterial strains and species, a range of different phospholipid and LPS fragments and variants have been parametrised for use in MD programs , insights into essential pathogen resistance development processes, membrane-targeting antimicrobial mechanisms, and generating fully artificial architectures that safely captures numerous essential pathogenic biological features can be made to help combat the devastating consequences of antibiotic resistance.Supplementary file1 (DOCX 31 KB)Below is the link to the electronic supplementary material.


This review focuses on nutritional support in malnourished children with compromised gastrointestinal function addressing the interplay between malnutrition and gastrointestinal dysfunction, and the specific role of peptide-based enteral therapy in pediatric malnutrition. Malnutrition is associated with impaired gut functions such as increased intestinal permeability, malabsorption, and diarrhea, while pre-existing functional gastrointestinal disorders may also lead to malnutrition. Presence of compromised gastrointestinal function in malnourished children is critical given that alterations such as malabsorption and increased intestinal permeability directly interfere with efficacy of nutritional support and recovery from malnutrition. Appropriate nutritional intervention is the key step in the management of malnutrition, while alterations in gastrointestinal functions in malnourished children are likely even in those with mild degree malnutrition. Therefore, nutritional therapy in children with compromised gastrointestinal function is considered to involve gut-protective interventions that address the overlapping and interacting effects of diarrhea, enteropathy and malnutrition to improve child survival and developmental potential in the long-term. Peptide-based enteral formulas seem to have clinical applications in malnourished children with compromised gastrointestinal function, given their association with improved gastrointestinal tolerance and absorption, better nitrogen retention/ balance, reduced diarrhea and bacterial translocation, enhanced fat absorption, and maintained/restored gut integrity as compared with free amino acid or whole-protein formulas. Malnutrition remains a major public health problem and a significant cause of mortality among children under five in low- and middle-income countries (LMICs), accounting for 45% of child deaths globally –4.Given the failure of global interventions to improve nutritional status and linear growth, factors that drive and sustain malnutrition have increasingly been addressed in epidemiologic and pathogenesis research . AccordiThe gut mucosa serves as a semipermeable barrier permitting nutrient absorption and regulating immune surveillance, while retaining potentially harmful microbes and environmental antigens within the intestinal lumen by preventing their translocation across the epithelial barrier , 8. The Indeed, growth and nutritional status impairment is also possible in children with functional gastrointestinal disorders, emphasizing that gastrointestinal dysfunctional alterations may appear as a consequence or cause of the malnutrition .On one hand, malnutrition causes alterations in gastrointestinal digestive and absorptive functions . ThOn the other hand, environmental enteric dysfunction (EED) with findings suggestive of impaired gut function  is considered as an important contributor to childhood malnutrition and stunting across geographically widespread resource-limited settings , 11–13. This review will focus on nutritional support in malnourished children with compromised gastrointestinal function, addressing bidirectional interplay between malnutrition and gastrointestinal dysfunction, and the specific role of peptide-based enteral therapy in pediatric malnutrition.Gastrointestinal aspects of malnutrition refer to operation of adaptation mechanisms to protein-calorie deficiencies and the environment, as well as to the direct relationship between the degree of nutritional deficiency and the severity of gastrointestinal dysfunction .Malnutrition has been documented to be associated with pancreatic exocrine insufficiency, altered intestinal blood flow, villous atrophy, and increased intestinal permeability which eventually lead to loss of digestive enzymes, secondary lactose intolerance, loss of colonic absorptive function, and diarrhea , 10. In The alterations in digestive physiology in childhood malnutrition is considered to be a combination of two synergistic factors including (1) malnutrition-dependent impaired reabsorption of bile salts, excessive bile salt deconjugation, pancreatic exocrine insufficiency  and impaired intestinal cell function  and (2) intestinal bacterial overgrowth and frequent bouts of diarrhea resulting in impaired gut defense and thus increasing the likelihood of further alterations of the microbiota as well as the diarrhea , 16.Malnutrition is associated with thinning of the entire intestinal wall and the mucosal lining along with reduced height of the brush border and predominance of cuboidal rather than columnar mucosal cells . PermeabCorrelations between several villus morphometry parameters and measures of gut function were reported in severely malnourished children, including positive correlations between villus height (VH) and villus perimeter , between permeability marker lactulose/rhamnose ratio (L/R) and gut microbial translocation indicator lipopolysaccharide binding protein (LBP), between LBP and villus width (inflammation) as well as negative correlations between the L/R and VP and between LR and VH .Malnutrition is associated with small intestinal villous blunting that leads to reduced intestinal capacity for monosaccharide and disaccharide absorption . ConsequIn malnourished children, protein malabsorption is considered likely due to pancreatic insufficiency and small intestine villus atrophy as well as increased protein loss due to increased intestinal permeability . ProteinIn fact, any impairment in protein digestion and absorption is considered more likely in severely malnourished children and in case of concomitant diarrhea, as associated with increased total fecal nitrogen, increased protein loss from the gut or to a minor impairment in protein digestion and/or amino acid absorption . ExcessiFat absorption is markedly impaired in over 50% of children with severe malnutrition , 26. AbnNotably, the severity of steatorrhea relates directly to the degree of protein deficiency and affects triglycerides and free fatty acids, emphasizing that lipolytic activity is not the primary cause of the increased fecal fat in malnutrition . BacteriNotably, improvement in fat absorption is considered to occur concomitantly with protein repletion, reaching normality in the absence of diarrhea and after restoration of body protein , 24.Preexisting gastrointestinal dysfunction itself may also lead to an increase in morbidity and mortality secondary to malnutrition, infection, and multi-organ dysfunction if not recognized and treated accordingly .EED is used to describe group of findings suggestive of impaired gut function  in many children across geographically widespread resource-limited settings . EED, a Chronic fecal-oral transmission of pathogens is considered the principal factor underlying EED , 32. EEDAlthough malabsorption and chronic inflammation arising from microbial translocation across an impaired gut barrier is suggested as the causal pathway for the link between EED and stunting , 32, 33,The adverse impact of metabolic stress and illness on the gut integrity increase the risk of malnutrition via loss of appetite, increased intestinal permeability, diarrhea, and malabsorption of nutrients, whereas those at risk for malnutrition are already at risk for compromised gut function including mucosal intestinal abnormalities and malabsorption of nutrients and vitamins , 34.Accordingly, bidirectional interplay between malnutrition and compromised gastrointestinal function emphasizes the importance of appropriate nutritional support in malnourished children that addresses the overlapping and interacting effects of diarrhea, enteropathy, and malnutrition to improve child survival and developmental potential in the long-term , 25, 35.Most commercially available enteral formulas consist of whole protein, carbohydrates, and fat . SpecialFormulas consisting of protein in the form of free amino acids (FAA) are also available for patients with malabsorption, food allergy, or specific organ diseases . These Due to presence of impaired gut function with severe mucosal abnormalities and malabsorption in malnourished children, standard enteral formulas may not be well-tolerated . DilutioIn a past study with 400 children (aged 12–59 months) living in rural Malawi, authors reported EED in 80.7% of children and identified 77 metabolites that were either negatively  or positively  associated with gut permeability . The autNotably, supplementation with glutamine, tryptophan, and leucine has been suggested to ameliorate the mucosal pathology by increasing villus height in adults with EED and to improve barrier function when combined with micronutrient supplementation . Hence aSome studies suggested that glutamine can reduce intestinal permeability in malnourished children and those with EED , 49, whiNotably, oral replenishment of specific amino acids  is considered likely to support intestinal epithelial cell proliferation and restoration of host growth, depending on combining treatment with targeted antibiotics and/or modulators against host inflammation , 52, 53.Experimental studies indicated the association of parenteral delivery of arginine with decreased intensity of Cryptosporidium infection and the severity of growth impairment in undernourished mice through induction of defense-promoting nitric oxide pathway and the arginase pathway that is important for intestinal epithelial cell restitution , 54. TryPeptide-based formulas contain proteins that have been hydrolyzed to produce peptides of varying lengths . PresencIndeed, non-competitive specific peptide carrier systems that are independent of free amino acid carriers have been identified in the intestinal brush border, and their importance has been confirmed in patients with impaired intestinal absorption .Providing protein in a form of a protein hydrolysate is suggested to directly affect nitrogen utilization and retention, regardless of the protein quantity or the non-protein calorie-to nitrogen ratio of a particular enteral formula . ClinicaAccordingly, the development of peptide-based enteral formulas is considered a significant milestone in the advancement of clinical nutrition, being associated with improved outcomes as compared with free amino acid or whole-protein formulas in terms of improved gastrointestinal tolerance –63, nitrThis seems important given that protein hydrolysates are also considered to improve sodium and water absorption alongside nutrient absorption depending on the type of protein substrate used for the production of hydrolysate , while protein hydrolysates with a higher concentration of small peptides are also associated with a greater stimulatory effect on nutrient as well as on sodium and water absorption . Given tThe carbohydrate component of peptide-based formulas is quite similar , mainly consisting of glucose oligosaccharides, which are easily metabolized and broken down during luminal hydrolysis and mucosal absorption .The quantity of fat provided in the peptide-based formulas ranges from 10 g/L fat up to over 50 g/L fat. Although it is still controversial whether the quantity of fat affects absorption, use of medium chain triglycerides (MCT) as a fat source in all peptide-based diets (up to 40–70%) is considered very important given the likelihood of MCT to further enhance lipid absorption, particularly in patients with underlying malabsorption syndromes , 64, 65.The smaller molecular weight of MCTs than long-chain triglycerides (LCTs) facilitates the action of pancreatic lipase and thus enables MCTs to be hydrolyzed both faster and more completely than LCTs with a reduction in stool lipid excretion , 66. NotAlthough an increase in the energy density of foods and thus provision of adequate energy in diet is often achieved by increasing the lipid content , in chilUse of peptide-based formula vs. standard whole (intact) protein formula has been associated with reduced rate of tube feeding diarrhea (44.0 vs. 0.0%) in ICU patients , while sPeptide-based formulas, as compared with FAA or whole-protein formulas, were reported to improve nitrogen balance and visceral protein synthesis, to reduce diarrhea and bacterial translocation, to maintain or restore gut integrity and to improve outcomes .Immune-enhancing formulas contain specific immune modulating nutrients , while the protein composition can vary . Data fAlthough the exact pathophysiological mechanisms remain unknown, the switch from a catabolic to an anabolic state via rapid refeeding in a starved patient is considered likely to cause of the clinical manifestations of the refeeding syndrome (RFS) , 80. WhiIn fact, in addition to favorable tolerability, digestion, and absorption characteristics, peptide-based diets have also been reported to be superior over AAF, parenteral nutrition and regular oral diets in terms of weight gain and growth, reduction of the systemic inflammatory response and lower mortality rates across a multitude of patient populations . AccordiFaecalibacterium prausnitzii and Bacteroides), despite clinical improvement, particularly in those proceeded to have a subsequent sustained remission  added to enteral formulations to extend their shelflife and texture has been associated with intestinal dysbiosis by reducing the alpha diversity and microbial stability of the intestinal microflora, promoting colitis, and metabolic syndrome , 87. MorMalnutrition is associated with gastrointestinal alterations such as increased intestinal permeability, malabsorption and diarrhea , 10. EEDAAS had primary responsibility for final content. All authors read and approved the final manuscript.AAS and SE are Abbott employees. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.