The placenta participates in cholesterol biosynthesis and metabolism and regulates exchange between the maternal and fetal compartments. The fetus has high cholesterol requirements, and it is taken up and synthesized at elevated rates during pregnancy. In placental cells, the major source of cholesterol is the internalization of lipoprotein particles from maternal circulation by mechanisms that are not fully understood. As in hepatocytes, syncytiotrophoblast uptake of lipoprotein cholesterol involves lipoprotein receptors such as low-density lipoprotein receptor (LDLR) and scavenger receptor class B type I (SR-BI). Efflux outside the cells requires proteins such as the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1. However, mechanisms associated with intracellular traffic of cholesterol in syncytiotrophoblasts are mostly unknown. In hepatocytes, uptaken cholesterol is transported to acidic late endosomes (LE) and lysosomes (LY). Proteins such as Niemann–Pick type C 1 (NPC1), NPC2, and StAR related lipid transfer domain containing 3 (STARD3) are required for cholesterol exit from the LE/LY. These proteins transfer cholesterol from the lumen of the LE/LY into the LE/LY-limiting membrane and then export it to the endoplasmic reticulum, mitochondria, or plasma membrane. Although the production, metabolism, and transport of cholesterol in placental cells are well explored, there is little information on the role of proteins related to intracellular cholesterol traffic in placental cells during physiological or pathological pregnancies. Such studies would be relevant for understanding fetal and placental cholesterol management. Oxidative stress, induced by generating excess reactive oxygen species (ROS), plays a critical role in regulating various cellular and biological functions and has emerged as a critical common mechanism after lysosomal and mitochondrial dysfunction. This review discusses the role of cholesterol, lysosomal and mitochondrial dysfunction, and ROS in the development and progression of hypercholesterolemic pregnancies. The placenta is a large organ that develops during pregnancy, enabling optimal fetal growth. It can adapt to diverse external factors both structurally and functionally. In adaptation problems during placenta development, fetal survival or fetal growth will be in danger, and diseases could develop . In addiThe different essential functions of the placenta include biosynthesis, metabolism, and transport of cholesterol, glucocorticoids, and sex hormones.This article compares the hepatic and placental cellular management of cholesterol under physiological conditions and provides an overview of the changes observed due to preeclampsia and maternal hypercholesterolemic pregnancies. We will also discuss the role of cholesterol accumulation in syncytiotrophoblasts due to maternal hypercholesterolemia resulting from lysosomal and mitochondrial dysfunction and oxidative stress.Cholesterol is a sterol that was first isolated from gallstones. It is biosynthesized by all animal cells and is an essential structural component of cell membranes in mammals . CholestIn physiological conditions, cellular cholesterol homeostasis includes tightly regulated processes. The body has two major sources of available cholesterol: (i) intestinal absorption of dietary and biliary cholesterol; and (ii) cholesterol biosynthesis in various tissues, predominantly in the liver and intestine. There are two main pathways for cholesterol excretion: (i) cholesterol excretion through the gastrointestinal tract and skin; and (ii) converting cholesterol to other compounds such as bile acids and steroid hormones . It is iGiven the complex regulation and diverse functions attributable to sterols, it is perhaps not surprising that inherited defects of genes involved in cholesterol metabolism or changes in the function of proteins required for proper homeostasis led to diverse metabolic alterations . Before Mammalian liver cells contain several types of binding sites for plasma lipoproteins. Most cholesterol entering the cells is taken up by receptor-mediated uptake from lipoproteins. The core of lipoprotein particles is composed of triglycerides and cholesterol esters , while phospholipids and free cholesterol cover the particle surface. Endocytic circuits harbor substantial amounts of cholesterol that they acquire not only from lipoprotein uptake but also via membrane recycling and nanovesicular equilibration .Cholesterol import from LDL and high-density lipoprotein (HDL) occurs via LDL-receptor-mediated uptake (LDLR) and HDL-mediated reverse transport via the scavenger receptor SR-BI, respectively. Additional receptors can mediate LDL and modify LDL uptake ,13; howeLipoproteins are internalized via clathrin-coated pits into early endosomes. The receptor is recycled to the cell surface, and the LDL-particle is targeted for proteolytic and lipolytic degradation . AlternaAfter the action of lipase, free cholesterol appears in the late endosomes/lysosomes (LE/LY) . Free chIn contrast to NPC1 deficiency, the movement of endosomal cholesterol to the mitochondria is interrupted by NPC2 deficiency . NPC2 muTo eliminate cholesterol, hepatocytes, and other cell types, including placental cells, secrete cholesterol to extracellular lipid acceptors such as lipoproteins, a process known as cholesterol efflux ,31,32. IThe placental syncytiotrophoblast has several active transporters on the apical and basal side that may regulate fetal transport. Several ABC transporters are expressed in the human placenta, where they play a role in transporting endogenous and exogenous compounds.Previous studies by our group suggest that the ABCG1 transporter is mainly localized on the basolateral side of the trophoblast layer ,36, suggAmong the approximately 7000 inborn metabolic errors, there is a family of diseases that result from defects in genes involved in sterol metabolism ,38. For If we focus on cholesterol trafficking disorders, a study by Vanier et al.  first reAdditionally, Smith–Lemli–Opitz syndrome (SLOS) is characterized by abnormal 7-dehydrocholesterol (7DHC) accumulation. SLOS patient fibroblasts cultured in a lipid-depleted medium synthesize cholesterol but exhibit significant cholesterol trafficking defects and accumulate unesterified cholesterol in LE/LY . AdditioCongenital cholesterol metabolism defects have provided many fundamental insights into normal cholesterol homeostasis and cell biology. They have traditionally been viewed as discreet diseases with unique phenotypes; however, NPC and SLOS involve NPC pathway inhibition. Platt et al.  showed tSeveral studies have shown that maternal cholesterol can be transported to the fetus. The human placenta needs more than 1 g of cholesterol per day to facilitate fetal growth , and theDuring human pregnancy, the fetal circulation is separated from maternal blood by the placental barrier, which plays an essential role in fetal development and health by tightly regulating molecular exchange between the mother and the fetus . The plaExtravillous trophoblast cells (EVTs) are invasive mesenchymal cells which function to establish critical tissue connection in the developing placental–uterine interface. These cells proliferate and migrate from the cytotrophoblast in the anchoring villi of the placenta and invade the maternal decidua and myometrium and can induce vascular remodeling. The remodeling of uterine spiral arteries by EVTs is fundamental for effective placentation and perfusion of the intervillous space . EVT funThe STB is a polarized layer of cells. The apical side is in contact with the maternal blood, and the basal side is in contact with the extracellular matrix and the fetal endothelium. Therefore, the expression of receptor or transporter proteins on one side of the STB determines the directionality of the released molecules. Maternal-to-fetal cholesterol trafficking requires STB mediated cholesterol uptake from maternal LDL and HDL through the endocytic LDLR, and the HDL receptor SR-BI, respectively ,59, and Furthermore, the expression of LDLR mRNA in STB increases with advancing pregnancy in baboons . FinallyA summary of the published information on proteins involved in cholesterol transport and metabolism in different placental cell lines is presented in The efflux of cholesterol from the basal side of the STB is poorly understood. ABCA1 and ABCG1 are expressed in placental endothelial cells and STB and could mediate cholesterol efflux via ApoA-I (via ABCA1) or HDL (via ABCG1) ,63. In tThese observations suggest that cholesterol transport in the human placenta is similar to other tissues involved in cholesterol metabolism , where the abundance and function of lipoprotein receptors and cholesterol transporters are regulated by cholesterol levels .Placental intracellular cholesterol transport is still poorly understood  and requCholesterol is not measured in current obstetric practice. There are no reference ranges for circulating lipids during normal pregnancy because there is little evidence that elevated cholesterol levels are important. Normal pregnant women exhibit a physiological  increase of around 30–50% in the total plasma cholesterol (TC) levels in a condition described in a previous section, known as the MPH or control state  ,91. HoweMSPH is also associated with increased lipid peroxidation, levels of reactive oxygen species (ROS) and inflammation, in the placenta and fetus ,94 Figu. ConversInterestingly, MSPH neonatal TC levels are similar to those from normal pregnancies, suggesting some regulation of placental cholesterol traffic in MSPH pregnancies.MSPH is associated with increased expression of genes involved in lipid metabolism in the placenta, exposing the fetus to an environment with a different lipid composition and promoting vascular alterations . AdditioCholesterol ester levels and free cholesterol levels are lower and higher in placental cells from MSPH pregnancies, respectively . Free chFuenzalida et al.  showed tTherefore, MSPH may alter cholesterol trafficking and cholesterol content in placental trophoblasts to avoid exacerbated efflux of cholesterol to fetal circulation. Therefore, the absorption, transport, distribution, and supply of maternal lipids to the fetus are modulated by MSPH. However, how free cholesterol affects intracellular cholesterol pathways and cell viability is unknown.There is little information about cholesterol biosynthesis in the placenta. Cholesterol synthesis and HMGCR activity in humans decrease as pregnancy progresses ,103.With advancing gestational age, novo cholesterol biosynthesis is markedly sup-pressed, with elevated concentrations of maternal serum-derived cholesterol, which re-places endogenously produced cholesterol as the major substrate of placental progesterone production in humans . The addInterestingly, maternal hypercholesterolemia does not change placental HMGCR protein levels nor free placental cholesterol or cholesteryl ester content . InsteadLysosomes are important for various cell functions, including exocytosis, endocytosis/phagocytosis, autophagy, cell growth and death . Many ofAdditionally, cholesterol circulation between late endosome/lysosomes (LE/LY) influences endomembrane traffic ,42. ThesCholesterol is oxidized by enzymatic or ROS-mediated pathways when present in excess levels. Oxidized cholesterol increases in the cytoplasm  and disrAs stated above, oxidative stress is an important factor in many complications during the second and third trimester of pregnancy. Preeclampsia, the most investigated pregnancy complication, develops in the second or third trimester and is characterized by maternal endothelial cell dysfunction resulting in systemic endovascular inflammation. This could cause symptoms such as proteinuria and hypertension. Inadequate extravillous trophoblast (EVT) invasion could result in an imbalance of oxidant/antioxidant activity when antioxidant capacity does not keep pace with increased oxygen tension, leading to a chronic state of oxidative stress. Early preeclampsia is often accompanied by fetal growth restriction ,108, whiWatson et al.  showed tCholesterol accumulation and defects in cholesterol trafficking cause severe disease in humans and animal models. Cholesterol availability during pregnancy and its flux between the placenta and fetus are poorly described. Further investigation is needed to uncover the precise mechanisms of cholesterol trafficking between the mother and fetus. Additionally, the expression of proteins involved in cholesterol trafficking during pregnancy under normal and pathological conditions has barely been investigated.We have established two main gaps in our knowledge of placental cholesterol trafficking: (1) The exact expression, localization, function, and regulation of key proteins required for proper intracellular cholesterol traffic  are unknown. (2) It is unknown whether higher maternal levels of total and LDL cholesterol affect intracellular cholesterol trafficking in placental cells. However, high total and LDL cholesterol levels impair lysosomal and mitochondrial function and cell viability in other cell types see . Therefo


Since next generation sequencing facilitated high-throughput and cost-efficient genomics analyses, the human gut metagenome has become an emerging frontier to explore toward precision nutrition. Significant progress has been made in identifying gut microbial features associated with a wide spectrum of human disease. However, other than a few microbiome-disease relations, there is a dearth of confirmed causal inferences, particularly in generally healthy populations. The relatively high unexplained variability in microbiome compositions in this group warrants caution in applying this complex biomarker toward precision nutrition, because our understanding of what constitutes a healthy microbiome is still rudimentary. Although gut microbiota harbor integrated environmental and host-specific information with the potential to facilitate personalized nutritional and lifestyle advice, these data cannot yet be confidently interpreted toward precise recommendations. Thus, nutritional advice for generally healthy individuals based on personal microbiome composition analysis might not yet be appropriate unless accompanied by established blood and physiological biomarkers. Gut microbiome composition analysis can offer deep layers of health data, but these insights are not yet useful toward precision nutrition for generally healthy individuals. No longer in its infancy, gut microbiome research is producing insightful results ripe for evaluation toward application to precision nutrition. However, the factors that contribute to a healthy  state of the intestinal microbiota are dauntingly complex: an interplay of genetic, environmental, clinical, and stochastic inputs can result in 2 seemingly healthy individuals' microbiomes having almost nothing in common from a taxonomic standpoint . AlthougAlthough this field has progressed exponentially toward more granular datasets, replication of bacterial species-level associations with host phenotypes is scarce, with the most promising reports correlating these associations with easily measured blood biomarkers or phenotypes. Thus, current gut microbial signatures could be just another, albeit highly elaborate, proxy for causal mechanisms behind health states yet to be discovered  gene associated with lactase persistence positively correlates with Bifidobacterium abundance, including a large meta-analysis of >18,000 individuals from diverse populations (FUT2 (fucosylated mucus glycan secretor/non-secretor) variant and Ruminococcus torques genus group. Thus, certain host genetic variations that correlate with the enrichment of particular gut bacterial species can explain host health state phenotypes (such as HDL or BMI); conversely, different subsets of SNPs that associate with particular host predispositions (such as lactose intolerance) can impact the composition of the microbiome. Exploration of such dynamics is in its infancy in generally healthy people and, though the effect sizes are likely to be small relative to the aforementioned nongenomic factors, they could ultimately add more granular insight at the level of individualized interventions. Such detailed analysis could only be useful when the more salient microbiome influencing factors, such as geographical location, are first accounted for.Individual host genetics contribute a relatively minor portion of the variation within a person's microbiome, with lifestyle factors such as long-term diet substantially outweighing the contribution of any single nucleotide polymorphism (SNP) . Xu et aulations . This paulations . Kurilshulations  also repAfter examining hundreds of health status phenotypes in >7000 individuals from 14 regions within the Guangdong province of southern China, He et al.  found thReports reveal that there is likely a measurable impact of prescription drugs, over-the-counter medications, and dietary supplements on species-level microbiota, yet the effects of most of these products remain unexplored. Vila et al.  reportedl-carnitine and/or choline leads to the production of trimethylamine (TMA) by the microbiome, which, when oxidized to trimethylamine N-oxide in the liver, is associated with an increased risk of cardiovascular disease  phenotypes, the interpretation of individual microbiomes toward personalized recommendations remains a challenge. Importantly, because intraindividual microbiome composition variability has been established as much lower than interindividual differences, it follows that each individual should harbor personalized species abundance averages that define their state of health. Nonetheless, even within-person microbiome variability can be partly a function of the frequency of sampling. Thus, temporal variability should be adjusted in longitudinal samples toward establishing individualized bacterial abundance metrics that would allow for more accurate assessments of metabolic capacities and facilitate “thresholds” for triggering personalized recommendations. Until microbiome analysis matures to a stage where consistent bacterial species’ functional effects have been demonstrated in independent studies spanning various demographics, it appears to be premature for metagenomics, in and of itself, to serve as a cost-effective solution or a reliable biomarker of wellness in individuals who are generally healthy. However, casting a wide ‘omics net, including metagenomics at the individual level, in future longitudinal studies, such as the NIH Nutrition for Precision Health program, should enable utrition .


Circular RNAs (circRNAs) are a novel type of non-coding RNAs that have aroused growing attention in this decade. They are widely expressed in eukaryotes and generally have high stability owing to their special closed-loop structure. Many circRNAs are abundant, evolutionarily conserved, and exhibit cell-type-specific and tissue-specific expression patterns. Mounting evidence suggests that circRNAs have regulatory potency for gene expression by acting as microRNA sponges, interacting with proteins, regulating transcription, or directly undergoing translation. Dysregulated expression of circRNAs were found in many pathological conditions and contribute to the pathogenesis and progression of various disorders, including renal diseases. Recent studies have revealed that circRNAs may serve as novel reliable biomarkers for the diagnosis and prognosis prediction of multiple kidney diseases, such as renal cell carcinoma (RCC), acute kidney injury (AKI), diabetic kidney disease (DKD), and other glomerular diseases. Furthermore, circRNAs expressed by intrinsic kidney cells are shown to play a substantial role in kidney injury, mostly reported in DKD and RCC. Herein, we review the biogenesis and biological functions of circRNAs, and summarize their roles as promising biomarkers and therapeutic targets in common kidney diseases. Circular RNAs (circRNAs) are a new type of non-coding RNA molecules that have attracted more and more attention in recent years . AlthougSince the recent findings that circRNAs are ubiquitous in human tissues and differentially expressed under pathological states, their functional relevance in diseases have been increasingly explored. The majority of researches have been focused on their roles in cancer , cardiovCircRNAs are transcribed from pre-mRNAs through a non-canonical splicing event called back-splicing , which iThe regulation of circRNAs biogenesis is crucial for characterizing their functional roles under pathophysiological conditions, but is still largely unclear. Emerging lines of evidence have identified that several regulatory mediators are involved in circRNAs formation . As mentOne prominent characteristic of circRNAs is that they are strikingly more stable than other types of RNAs, including linear mRNAs and other non-coding RNAs. One study compared the half-lives of four ecircRNAs and their associated linear transcripts and found the ecircRNAs consistently exhibited long half-lives exceeding 48 h in contrast to linear counterparts with half-lives <20 h . The higThe biological functions of circRNAs have been extensively investigated in recent decade. Similar to miRNAs and long non-coding RNAs (lncRNAs), circRNAs have also been found to play an important role in the regulation of gene expression. They may modulate gene expression by distinct modes of action at transcriptional or post-transcriptional levels. The most well-characterized mechanism is to act as sponges for miRNAs , 15; Fig. Meanwhiin vitro produced a substantial reduction of knockdown effect by miR-7 on its targets, while repressing ciRS-7 levels by miR-671 regained the inhibition on targets genes by miR-7, supporting the role of ciRS-7 as a highly functional sponge for miR-7 , which harbors 16 putative target sites for miR-138 in mouse, was demonstrated to serve as a sponge for miR-138 in vitro  of messenger RNAs (mRNAs). Many studies have found that circRNAs harboring miRNA binding sites could compete with mRNAs for miRNAs binding and function as miRNA sponges, thus indirectly affect gene expression. The first-characterized and most well-known circRNA to support this model is ciRS-7 (circRNA sponge for miR-7), which contains more than 70 conserved binding sites for miR-7 , 15. CiRor miR-7 , arguingin vitro . Anotherin vitro . Althougin vitro , implyinper se could regulate gene expression at splicing levels. Furthermore, certain circRNAs could also modulate gene transcription. Unlike ecircRNAs which are mainly localized in the cytoplasm, intron-containing circRNAs including EIciRNAs and ciRNAs are more likely to be retained in the nucleus in human cells  locus could synthesize a protein product as detected by mass spectrometry (6A) was demonstrated to be capable to drive translation of circRNAs  or cisplatin treatment , 66. IntGlomerular diseases refer to a large group of diseases that injuries mainly involve bilateral glomeruli, which can be classified into three categories: primary, secondary, and inherited glomerular diseases. Glomerular diseases have a very high morbidity worldwide and remain the primary cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD), which pose huge burden on society and economy. At present, the diagnosis of glomerular diseases mainly depends on invasive kidney biopsy and reliable indicators for predicting clinical outcomes of specific glomerular diseases are lacking. Recently, increasing studies have focused on the expression and roles of circRNAs in the diagnosis and prognosis prediction of various glomerular diseases.db/db mouse model by microarray analysis (in vitro high glucose (HG)-treated glomerular endothelial cells (GECs) model and obtained exosomal circRNA profiles secreted by GECs using high-throughput sequencing. Compared to normal glucose (NG)-treated GEC exosomes, 217 circRNAs were significantly down-regulated while 484 were up-regulated in HG-treated GEC exosomes (Diabetic kidney disease (DKD) is one of the most frequent complications of diabetes mellitus and the leading cause of CKD worldwide, which is pathologically characterized by mesangial cells (MCs) proliferation, extracellular matrix (ECM) accumulation, and basement membrane thickening. Nevertheless, there are few reports evaluating the roles of circRNAs as biomarkers in DKD up to date. One study investigated the differentially expressed (DE) circRNA profiles in the analysis . Anotheranalysis . Circ_00analysis . Anotherexosomes . The levexosomes . MoreoveIgA nephropathy (IgAN) is the most common type of primary glomerulonephritis worldwide. To date, only two studies have analyzed the dysregulated circRNAs profiles in IgAN patients , 73. TheMembranous nephropathy (MN) is another common type of glomerulopathy with increasing frequency over the past decades . A preliLupus nephritis (LN) is the most common complication of systemic lupus erythematosus (SLE) and 10–30% of LN patients will progress to ESRD . Initialin vitro cell culture experiments, these studies provide novel avenues to elucidate the mechanisms underlying kidney diseases and make circRNAs novel promising therapeutic targets in this realm.Although lots of efforts have been made in kidney diseases field, the pathogenesis of most renal disorders remains largely unclear, which hinders the development of specific therapeutic strategies to treat these diseases. Since circRNAs could regulate gene expression and are differentially expressed under pathological conditions, they are probably biologically functional in diseases. In fact, current data indicate that circRNAs are involved in the pathogenesis and progression of cancer , cardiovin vivo, suggesting hsa_circ_0035483 could be a promising therapeutic target of gemcitabine resistance in RCC treatment. In vivo manipulation of circRNAs expression is vital to clarify their functional relevance. In fact, many studies have already explored the effect of interfering with circRNAs expression on RCC growth and metastasis in vivo , a common histopathological lesion which is characterized by segmental glomerular scarring, is one of the leading causes of adult nephrotic syndrome and ESRD worldwide. One study found that circZNF609 was up-regulated in both adriamycin-induced FSGS mouse kidneys and bovine serum albumin (BSA)-treated HK-2 cells, while miR-615-5p showed the opposite trend . The intHypertension is a common chronic disease with a high prevalence in the general population which frequently produces adverse effects on certain target organs, including heart, blood vessels, and kidney. Recent studies indicate many circRNAs were aberrantly expressed in blood samples of hypertensive patients or kidneys of hypertensive models –111. AmoVascular calcification (VC) is one of the common complications in CKD patients. One study using RNA sequencing identified that a large number of circRNAs changed significantly in a cellular model of VC . Among tRecent advances in the circRNA research field have uncovered their diversified functions in health and disease. In the past 5 years, increasing endeavors have identified numerous circRNAs involved in the pathogenesis and progression of various kidney diseases. These putative circRNAs function mainly through circRNA-miRNA-mRNA networks, expanding our understanding of regulatory mechanisms underlying kidney disorders. In addition, owing to their impressive stability, circRNAs have been validated as reliable biomarkers for diagnosis and prognosis prediction of multiple kidney diseases. Results of these investigations support that circRNAs possess the promising potential as both biomarkers and therapeutic targets in the kidney realm.in vivo and whether interfering specific circRNAs expression would produce off-target effects remains uncharacterized. Nevertheless, it is becoming clear that increasing exploration into the potential roles of circRNAs will extend our understanding of kidney diseases and hopefully will become an intense area of research in the near future.However, we have to admit that there are shortcomings regarding current research and many challenges remain to be overcome in this field. Firstly, most studies investigating circRNAs as biomarkers are from single-center, with small sample sizes, and lack of independent external cohort validation. Larger independent cohorts from multi-center settings are highly desirable to validate candidate circRNAs as promising biomarkers. In addition, there are few studies searching for biomarkers to monitor treatment efficacy or predict relapse of glomerular diseases, including nephritic syndrome, lupus nephritis, and vasculitis-associated renal lesions. Exosomal circRNAs in blood and urine are promising biomarkers for non-invasive liquid biopsy and more standardized techniques are desired to reliably detect these exosomal circRNAs. Secondly, the vast majority of aberrantly expressed circRNAs have not been studied functionally and those possibly as hub genes in signaling pathways underlying kidney diseases remain to be identified. To date, most studies on circRNAs are focused on their function as miRNA sponges. It is likely that those dysregulated circRNAs may function through other regulatory mechanisms, such as transcription regulation or acting as RBP sponges, which warrants further research. Last but not the least, the biological functions and therapeutic potential of candidate circRNAs need to be verified in animal models, including non-human primates. There is still lack of ways to specifically and efficiently deliver circRNAs into recipient cells JY and DX wrote the manuscript. NH drew the figure and tables. QZ supervised the manuscript. All authors contributed to article design, revision, read, and approved the submitted version.This study was supported by program from Guangdong Basic and Applied Basic Research Foundation (2020A1515010247); Guangzhou Science and Technology Innovation Commission (201806010123); Kelin Young Talents Program of the First Affiliated Hospital of Sun Yat-sen University (Y50179); National Key R&D Program of China (2016YFC0906101); Operational Grant of Guangdong Provincial Key Laboratory (2017B030314019); Guangdong Provincial Programme of Science and Technology (2017A050503003 and 2017B020227006); Guangzhou Municipal Programme of Science and Technology (201704020167); Natural Science Foundation of Guangdong Province, China (Grant No. 2017A030310199); and National Natural Science Foundation Grant (82170732).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.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. 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Soft tissue sarcomas (STSs) are a family of rare malignant tumors encompassing more than 80 histologies. Current therapies for metastatic STS, a condition that affects roughly half of patients, have limited efficacy, making innovative therapeutic strategies urgently needed. From a molecular point of view, STSs can be classified as translocation-related and those with a heavily rearranged genotype. Although only the latter display an increased mutational burden, molecular profiles suggestive of an “immune hot” tumor microenvironment are observed across STS histologies, and response to immunotherapy has been reported in both translocation-related and genetic complex STSs. These data reinforce the notion that immunity in STSs is multifaceted and influenced by both genetic and epigenetic determinants. Cumulative evidence indicates that a fine characterization of STSs at different levels is required to identify biomarkers predictive of immunotherapy response and to discover targetable pathways to switch on the immune sensitivity of “immune cold” tumors. In this review, we will summarize recent findings on the interplay between genetic landscape, molecular profiling and immunity in STSs. Immunological and molecular features will be discussed for their prognostic value in selected STS histologies. Finally, the local and systemic immunomodulatory effects of the targeted drugs imatinib and sunitinib will be discussed. The immune system serves as a safeguard against cancer development by eliminating cells harboring traits of genomic instability, such as unbalanced karyotype, copy number alterations and mutations in canonical drivers. Tumor genotype has also a direct effect on redirecting the host immune system . The bluSoft tissue sarcomas (STSs) include a variety of histological and molecular different rare malignant tumors with a wide range of differentiation towards mesenchymal lineages including muscle, adipose and other connective tissues. Genetically, STSs include tumors characterized by specific translocations which become driver of tumor pathogenesis and precise diagnostic markers, and tumors that display complex genomics alterations which include copy number alterations, mutations in canonical drivers and in general are characterized by a deep genetics and chromosomal instability.STSs display a wide range of clinical behavior from low grade to high grade tumors that are characterized by an increased risk of metastatic spread. Surgery is the mainstay of treatment for localized disease, while systemic treatments, including chemotherapy or targeted therapy, are used for patients with metastasis. Recently, clinical trials tested immunotherapy strategies in STSs, showing effectiveness in selected histologies such as dedifferentiated liposarcoma (DDLPS) and undifferentiated pleomorphic sarcoma (UPS) . HoweverFrom an immunogenomic perspective, only sarcomas carrying complex karyotypes could selectively display an “immune hot”, heavily immune infiltrated tumor microenvironment (TME), making these tumors the only sarcomas likely to be responsive to immunotherapy. However, the epigenetic regulation of the transcriptional program, occurring at different levels, including DNA methylation, histone modification and chromatin remodeling, influences the tumor immune landscape . For insThese epigenetic mechanisms influencing immunity are likely active in mesenchymal neoplasms, such as sarcomas, in which alterations in chromatin regulator genes are common . For insNonetheless, some variations in the immune properties of each tumor can be heritable and determined by the germline genotype of the host, adding a level of complexity in the molecular determination of TME composition and functional orientation ,12.Compared to other tumors, characterization of immune infiltrate in sarcomas is in its infancy and a systematic exploration of correlations between tumor genetic and immune signatures, that also account for the distinctive features of each sarcoma histotype, is needed. The present review aims at picturing the complexity of sarcoma immunity and discussing genetic and epigenetic mechanisms that influence the sarcoma immune contexture.STSs are a heterogenous group of mesenchymal tumors. The 2020 WHO classification of Soft Tissue and Bone Tumors  clearly Great help in the definition of each single entity is nowadays provided by the identification of sarcoma histology-specific molecular alterations.Sarcomas are classified into two main large groups, differing at the cytogenetic level. The group characterized by relatively simple karyotypes includes sarcomas with chromosomal translocations leading to fusion oncogenes  and alveolar rhabdomyosarcoma (ARMS), respectively) and oncogene-mutated sarcomas . Translocated sarcomas often affect children and young adults, people in whom tumorigenesis occurs from a small number of genetic events. Epigenetic mechanisms of gene regulation are involved in the majority of translocated sarcomas. FUS and EWSR1, which are the most common fusion partners in translocated fusion oncoproteins and characterize several sarcoma histologies, are drivers of the three-dimensional chromatin structure. An additional example of translocated sarcoma is synovial sarcoma (SS), which is among the common histologies localized in the extremity and superficial trunk and is characterized by a translocation which causes the fusion of SSX1 or 2 or 4 with SS18. The resulting chimeric oncoprotein is involved in chromatin remodeling .The second group of STSs presents complex karyotypes, and are characterized by genomic instability. Sarcomas with a complex karyotype and non-reproducible genetic alterations usually occur in older patients who have accumulated numerous mutations or genetic deregulations, and they account for more than half of STSs. They are characterized by pleomorphic/spindle cell morphology and include pleomorphic/DDLPS, leiomiosarcoma (LMS) and pleomorphic leiomiosarcoma (PLPS), pleomorphic rabdomiosarcoma, malignant peripheral nerve sheath tumor (MPNST), myxofibrosarcoma (MFS), UPS and embryonal rhabdomyosarcoma (ERMS) for which complex karyotype is generally reported, although loss of heterozygosity of 11p15 region is found in most cases of ERMS. Among these tumors, UPS is the most frequently occurring sarcoma of extremity and trunk wall and has gained interest in the sarcoma community for being a polyclonal disease in which ICIs showed effectiveness in phase I and II clinical trials ,17,18.Advances in next-generation sequencing (NGS) technologies, such as whole-exome sequencing (WES) and whole-genome sequencing (WGS), are contributing to the discovery of novel genetic alterations within different sarcomas. The genomic landscape of each STS has helped re-classifying intra-histologic entities and also opened up avenues for targeted histology-specific treatment strategies. NGS approaches also uncover genetic alterations missed by conventional molecular diagnostic approaches, such as KIT/PDGFRA/SDH/RAS-P GIST, which was identified among wild-type GISTs ,20. ThesTranscriptomic sequencing  and proteomic-based approaches  integrated the tumor genetic landscape with the tumor immune profiling. In this context, NGS techniques have been applied to sarcoma to derive immune cell frequencies, the expression profile of immune-related genes, and also the T cell repertoire at the tumor site . IntriguBesides the genetic approaches, immunohistochemistry (IHC) remains a fundamental technique to investigate the TME. The recent development of high-throughput multiplex IHC, able to dissect multiple markers on a single slide, and of related digital imaging analysis systems has certainly boosted the potentiality of this technique. Moreover, IHC is used as either a standalone approach or often applied to validate transcriptomic data, allowing analysis of protein expression on intact tissue sections. This gives crucial information on the co-expression profiles of different immune markers and on their reciprocal intra-tumoral cellular distribution ,27. ThesSarcomas with simple karyotype are characterized by specific driving alterations, including oncogenic mutations and translocations that univocally identified a distinct sarcoma. Constitutive activation of oncogenic signaling pathways that are caused by mutations in oncogenes negatively impacts the immune TME by promoting intratumoral immune cell exclusion or favoring the recruitment of immunosuppressive cells ,6. This Studies addressing genetic mutational status, oncogenic pathway activation and their association with immunological features in sarcomas are in early stages. Among STSs, GIST represents the most investigated disease from this viewpoint. This tumor is driven by mutated oncogenes as it is characterized by gain of function mutations in the KIT or PDGFRA proto-oncogene. Although KIT- and PDGFRA-mutated GISTs display different clinicopathologic features, the mechanisms linking mutation to the different biological behaviors have not been understood yet. The majority of PDGFRA-mutant GISTs harbor D842V mutation in exon 18 and, more rarely, mutations in exons 12 and 14. Of note, D842V mutation is the one known to confer primary resistance to imatinib. Interestingly, recent data suggest that PDGFRA-mutant GISTs, and especially those with the D842V mutation, express higher levels of immune-related genes and are characterized by higher immunological activity compared to the KIT-mutated GISTs, or non-D842V mutant GISTs ,30. In gPart of the clinical success of the imatinib targeted therapy in KIT-mutated GIST likely also relies on immune-related effects involving both innate and adaptive immunity. In fact, it has been shown that in patients with gastrointestinal tumors, imatinib boosts the IFNα secretion by natural killer cells and concomitantly, it decreases regulatory T cell numbers by inducing their apoptotic death . ImatiniA correlation between fingerprint mutations and immunity at the tumor site has also been recently reported for angiosarcomas, a rare group of sarcomas arising from endothelial cells of vessels that harbor mutations in angiogenic and oncogenic signaling pathways. These tumors are often characterized by multifocal lesions and poor outcomes. A recent study reported that a subset of angiosarcoma overexpresses at transcriptional level inflammation- and immune-related signaling pathway genes and is characterized by a high number of neutrophils (CD15+), macrophages (CD68+), cytotoxic T (CD8+), Tregs (FOXP3+) and PD-L1+ immune cells. Immune inflammation signatures were enriched in two mutually exclusive angiosarcoma groups, one harboring UV-related signature (and thus displaying high TMB) and the second positive for human herpes virus-7 (HHV-7). HHV-7 virus might directly drive inflammation-related pathways, including IFN response genes and, conversely, evoke immune evasion, finally leading to an exhausted TME . ClearlyEpigenetic dysregulation can be induced at different levels, which include alterations in DNA methylation patterns, histone mutations and modifications, alterations in chromatin remodeling complexes and in 3D chromatin structure ,37. TranUnfortunately, the majority of fusion oncoproteins cannot be considered actionable targets for therapeutic intervention and alternative therapeutic approaches aimed at targeting epigenetic dysregulated factors have been considered. Sarcomas, such as SS and ARMS, characterized by the disruption of the SWI/SNF chromatin modifier complex, show overactivation of methyltransferase EZH2, which can be targeted by Tazemetostat . ImportaHowever, in general, a deeper characterization of mechanisms of action of epigenetic drugs and their off-target effects is needed and is mandatory to optimize their use in clinical settings. From this perspective, as in other tumors, such as melanoma and clear cell renal cell carcinoma, alterations of genes encoding modifiers of the SWI/SNF chromatin remodeling are associated with response to ICIs ,8. HowevAn initial attempt in this direction has been recently pursued for SS. Indeed, SS fusion oncoprotein SS18–SSX inhibits cell differentiation, sustains cell cycle progression and is negatively associated with immune infiltrate. Treatment of SS cells with epigenetic drugs targeting HDAC and modulators of the cell cycle represses the oncogenic program, increases tumor cell immunogenicity and, importantly, oncogenic program can be suppressed by cytokines released by macrophages and T cells within the TME . Taken tIn sarcoma, mirroring other largely investigated tumors, genomic complexity translates to increased TMB and immune infiltrates. For instance, UPS, which is the most frequent STS arising in the extremities and superficial trunk, and with a high risk of disease progression, is characterized by complex karyotype and the lack of a specific line of histological differentiation . UPS disThe group of UPS lacking immune infiltrate was enriched in genes involved in tumor development and stemness, and in particular, it displayed an up-regulation of PI3K/AKT and Wnt/beta catenin pathways, which are well known to be associated with immune exclusion in many tumors, including other sarcomas ,49. PrecThe transcriptomic profiling analysis by the TCGA consortium revealed that UPS, MFS and DDLPS display a high macrophage score, regardless of T cell infiltration. Additionally, in UPS and MFS, the presence of dendritic cells and immature dendritic cells correlates with better survival, while enrichment of Th2 signature in DDLPS, although expressing the highest CD8 T cell score, correlates with shorter survival. Of note, these sarcoma histologies were marked by a high expression of druggable immune markers B7-H3, TGFB1 and TIM3 . FurtherThe presence of distinct phenotypes, according to the immune composition of the TME in DDLPS, MFS and UPS, was further confirmed in two additional studies ,52. In sTargeted therapy drugs belonging to the anti-angiogenic family, such as sunitinib and pazopanib, have been used for different STS histologies, including solitary fibrous tumors (SFT) and clear cell sarcomas (CSC). In these simple karyotype STSs, we have shown that these drugs modulate systemic and local host immune components ,56,57 anAdaptive immunity was boosted and found to be crucial also in the therapeutic responses to imatinib of fibrosarcomatous DFSP (FS-DFSP), a variant of DFSP characterized by occurrence of lung metastasis, an event that does not occur in pure DFSP ,60. IntrThese data are in line with increasing evidence indicating that epigenetic processes have a key role in the regulation of immune cell activity and anti-tumor response. Particularly, molecular events disrupting epigenetic balance at the tumor level could promote the escape of tumor cells from immune surveillance, mainly by down-regulating the expression of tumor-associated antigens, antigen-presenting machinery and co-stimulatory molecules .Interfering with epigenetic mechanisms also has a direct effect on immune cell subsets. For example, EZH2 targeting reprograms the functional activity of intratumoral regulatory T cells and activates and influences T cell differentiation and function ,63,64. RIt has been recently reported that aberrant activation of cell cycle in tumor cells promotes immune evasion. Genomic and transcriptomic studies revealed that amplification of cyclin D1 and CDK4 genes are associated with resistance to immunotherapy and that tumors with hyperexpression of genes promoting cell cycle display a “cold” immune tumor contexture. In addition, recent evidence demonstrates that treatment of tumors with CDK4/CDK6 inhibitors could restore regulatory mechanisms, including regulation of IFNγ signaling, antigen presentation machinery and cell release of immunomodulating factors, leading to improve the immune anti-tumor activity . Indeed,ICIs have substantially improved prognosis for several solid cancers, including malignant melanoma, lung, renal, urothelial and head and neck cancer. In STSs, the clinical benefit of ICIs showed controversial and in general unsatisfactory results. As outlined in this review, STSs include different histological types with different biological and consequently immunological features. Most importantly, each single histotype displays genetic variations that directly affect the TME composition. Thus, this large variety together with the relative low frequency of these rare tumors, certainly limit the possibility to clearly interpret the efficacy of ICI therapy in STSs and the development of predictive and reliable biomarkers to define which sarcoma patients are likely responsive to ICIs. To overcome these limits, systematic omics studies of STSs should be planned. In particular, transcriptional studies at single cell level should be performed in order to determine how tumor and non-tumor cells could promote the onset of resistance.A recent meta-analysis showed that high response rates to ICIs are found—besides in the classical Kaposi sarcoma, also in alveolar soft tissue sarcoma (ASPS) and in UPS, showing an ORR of 0.35 and 0.20, respectively . This reAn additional important conclusion of this meta-analysis study is that early incorporation of ICIs with chemotherapy or with TKI shows improved ORR rates in sarcoma patients, further stressing the value of the combination of ICIs with drugs endowed with immunomodulating properties. Chemotherapy in STSs is mainly based on the usage of antracycline, whose activities in inducing immunogenic cell death is well documented . ConversOn the basis of results obtained in other tumors, clearly indicating that non-immune pathways could impact response to ICI therapy, an additional combination therapy that can be proposed for STS will envisage the use of drugs targeting CDKs . In factICI response is strongly affected by the complex interplay between cancer cells and TME. A deep and systematic investigation of the immune niche of STSs is therefore mandatory to identify mechanisms promoting an immunosuppressive TME. Recent studies reported that in the majority of STSs, regardless of the histology and genetics, macrophages represent the dominant immune cell population, as they outnumber lymphocytes, and have a M2 pro-tumorigenic phenotype ,71. In aThis review addressed the interconnection between genomic characteristics and immune response in different sarcoma histologies . We highSeveral IHC-based studies of STS TME clearly documented an abundant myeloid cell infiltration spanning across sarcoma subtypes despite the simple and complex karyotype dichotomization. However, intra-tumoral myeloid composition and its relationship between active tumoral epigenetic and oncogenic programs is still an unexplored field. The precise role of these cells in tumor promotion and immunosuppression has been far less understood and advanced sequencing approaches, such as single cell RNA sequencing, should be applied to decipher their phenotypic and functional specifications. This could be translated into the identification of myeloid cells-based biomarkers that modify tumor response to immunotherapy as well as novel actionable targets, with the ultimate aim of providing sarcoma patients with effective treatment options that impact survival.


Brugada syndrome is an autosomal dominant arrhythmogenic disease associated with an increased risk of ventricular fibrillation and sudden cardiac death. The mainstay of treatment in high-risk patients is an implantable cardioverter-defibrillator (ICD), however radiofrequency ablation has been proposed over the past decade as an additional therapy in patients with recurrent ICD firing. We report a case of Brugada syndrome with an electrical storm which was successfully managed by radiofrequency ablation. Loss of function in the SCN5A gene, which controls voltage gated sodium channels, is found in approximately 30% of affected individuals  is an inherited condition characterized by ST-segment elevation in the right precordial leads, associated with ventricular arrhythmias (VAs) and sudden cardiac death (SCD), especially in young malesividuals 2.The standard therapy for the prevention of SCD in BrS is the use of an implantable cardioverter-defibrillator (ICD) especially in patients who have experienced a prior cardiac arrest or sustained VAs. However, ICDs do not prevent the occurrence of VAs but react to terminate/defibrillate the arrhythmic episode, thereby preventing SCD.3. In the last decade, substrate ablation of the right ventricular outflow tract (RVOT)/right ventricle (RV) has emerged as a promising therapeutic option for BrS patients with recurrent VAs.Quinidine has been reported to reduce the ventricular arrhythmic burden in BrS, however, quinidine is not widely available and has been associated with intolerable adverse effectsWe report the case of a 28-year-old male patient who was discovered to have Brugada pattern on his surface ECG, after resuscitation from sudden cardiac arrest . He fullAfter informed consent, the procedure was performed under general anesthesia. Two right femoral venous accesses were obtained, one for positioning of CS catheter, the other for endocardial mapping of RV. A Chiba spinal needle was used for the epicardial access. To avoid epicardial coronary artery injury, a coronary angiography was performed to visualize the course of the left anterior descending artery (LAD). High-density substrate mapping was performed on RV endocardium and epicardium using an Advisor HD grid mapping catheter and Ensite Precision mapping system .In sinus rhythm we looked for abnormal electrograms (EGMs) which included fractionated potentials, split EGMs, isolated late potentials and low voltage EGMs . These aThe patient recovered well after the procedure and was discharged home the next day. After one year of close follow up, there have been no recurrences of ventricular arrhythmias upon frequent interrogations of his ICD .et al in 2003, where they targeted premature ventricular complexes (PVCs) originating from RVOT that were thought to trigger VF. Given the fact that PVCs in patients with BrS could be quite scarce, wide clinical application of this idea was impractical4.Catheter ablation for BrS patients with recurrent VF was first introduced by Haïssaguerre 5. Over the following years, there was growing evidence that epicardial substrate modification is beneficial in abolishing the recurrence of VF. Most importantly, in 2011, Nademanee et al reported normalization of the ECG pattern and abolition of recurrent VF episodes after epicardial RVOT substrate ablation in a cohort of 9 patients with Brs and recurrent ICD shocks6.In 2009, an experimental study on mongrel dogs with induced Brugada pattern concluded that radiofrequency catheter ablation applied to the epicardium of the RVOT may be more effective than endocardium in elimination of VAs6. Recently, Talib et al, in a series of 21 patients, introduced an endocardial approach as a first step in ablation of patients with BrS with an overall success rate of 67% 8.In 2017 multicenter trial, Pappone, Brugada, Santinelli and colleagues published the results of epicardial ablation in 135 consecutive patients. In this large series, the study group determined the arrhythmogenic electrophysiological substrate before and after ajmaline provocation using three-dimensional electroanatomical mapping. Elimination of this substrate led to subsequent ECG normalization and VT/VF non-inducibility in all ablated patients. More importantly, the group reported no complications related to the pictureAs our case was a redo case, it was reasonable to map both endocardial and epicardial surfaces of the RV using high-density mapping technology to ensure full coverage of all possible electrical substrates. However, all significant signals were present only on the epicardial surface. Thorough high-density mapping, after sodium channel blocker infusion, clearly identified areas of abnormal EGMS that were possibly missed at the first attempt, or most likely, not sufficiently ablated.7.It is important to highlight that despite the invasive nature of epicardial mapping and ablation, studies on this approach for patients with BrS and other conditions, such as arrhythmogenic right ventricular cardiomyopathy and dilated cardiomyopathy, consistently showed low periprocedural complication rates. Careful handling of the puncture of the epicardial space with adequate experience and knowledge of fluoroscopic anatomy of RV, renders this approach mostly safe •Catheter ablation is a valid option in patients with BrS who experienced recurrent shocks. •The use of sodium channel blockers helps to unmask the specific electric substrate in BrS. •The appropriate use of up-to-date technologies, such as high-density mapping, can significantly improve the outcomes in complex ablation procedures.


Although social disengagement is considered to be a predictor of cognitive decline, and increase risk of Alzheimer’s and related dementias, little is known regarding the gender-specific association between social disengagement and cognition among Korean middle-aged and older adults. Korea’s Confucianism-based gender roles provide unique contexts to examine gender differences in the influence of social disengagement on cognition. This study investigated the association between social disengagement and cognitive function in a nationally representative sample of Koreans aged 45 years or older , using data from the Korean Longitudinal Study of Aging (2008-2018). Results from the generalized estimating equation model showed that compared to consistent social engagement, consistent non-engagement was significantly associated with lower cognitive function among both genders. Transitioning from social engagement to non-engagement was significant for males only. Of various types of social activities , consistent non-engagement in a senior center was most associated with lower cognitive function among both genders, while consistent non-engagement in religious activities was significant for females only. While household arrangements were not associated with cognition in men, widowed women had increased risk of cognitive decline than married women, as did women living in households of three or more people. Depression was a predictor of cognitive decline among males only. In this gender-specific study, we found that consistent participation in social activities, especially via membership in a senior community center, is beneficial in preventing cognitive decline among both genders.


Patients with hypertrophic cardiomyopathy (HCM) who have left ventricular outflow tract obstruction (LVOTO) often experience severe symptoms and functional limitation. Relief of LVOTO can be achieved by two invasive interventions, i.e., surgery myectomy and alcohol septal ablation (ASA), leading in experienced hands to a dramatic improvement in clinical status. Despite extensive research, however, the choice of the best option in individual patients remains challenging and poses numerous clinical dilemmas.Invasive strategies have been recently incorporated in recommendations for the diagnosis and treatment of HCM on both sides of the Atlantic. These guidelines are based on a bulk of well-designed but retrospective studies as well as on expert opinions. Evidence now exists that adequate evaluation and management of HCM requires a multidisciplinary team capable of choosing the best available options.Management of LVOTO still varies largely based on local expertise and patient preference. Following the trend that has emerged for other cardiac diseases amenable to invasive interventions, the concept of a “HCM heart team” is coming of age. Hypertrophic cardiomyopathy (HCM) is a complex cardiovascular disorder characterized by unexplained left ventricular (LV) thickening in the absence of hemodynamic overload due to cardiac or systemic disease . Two-thiPharmacologic therapy with betablockers, verapamil, and disopyramide represents the first-line strategy. However, when symptoms prove refractory to medical therapy and obstruction persists, invasive septal reduction strategies should be taken into consideration. The two established options currently available are surgical myectomy and alcohol septal ablation (ASA). Unfortunately, there are no randomized trials comparing myectomy and ASA and none are anticipated: a definitive comparison with regard to outcome is probably not feasible in a disease characterized by low event rates such as HCM. As a consequence, European and American scientific guidelines do not provide class I recommendations for any of these invasive options , 5 and tThis review aims to provide an update of invasive options for the management of LVOT in HCM, highlighting areas for multidisciplinary integration and future development.The pathophysiology of HCM was first described by Braunwald et al.  and WiglMultiple mechanisms are involved in the pathophysiology of LVOTO in HCM. The anatomic determinant is represented by hypertrophied basal anteroseptal wall and redundant mitral leaflets, coupled with a small-sized ventricular cavity. The functional determinant of obstruction is the systolic anterior motion (SAM) of the mitral valve and the consequent mitral-septal contact . SAM is LVOTO should be routinely sought during routine evaluation of HCM. Around 70% of patients exhibit significant obstruction with a peak pressure difference of more than 30 mm Hg . In abouObstruction in HCM should always be properly diagnosed and adequately treated, as it is a major determinant of patients’ clinical and hemodynamic status, and a determinant of outcome. Unfortunately, a large proportion of patients with dynamic obstruction remain symptomatic despite optimal drug treatment. In such occurrence, invasive treatment of LVOTO should be considered in symptomatic patients with an LVOT gradient ≥ 50 mm Hg, in spite of maximally tolerated drug therapy. Over the past decades, surgical septal myectomy and ASA have become the two established options in this challenging subset.The septal myectomy operation was initially proposed by Morrow with the aim to restore normal LV hemodynamics by surgically abolishing LVOTO . For decIn a tailored fashion, the surgical myectomy can be combined with additional procedures, as required, including mitral valve replacement, posterior-superior realignment of the papillary muscles, partial excision and mobilization of papillary muscles, anterior mitral leaflet plication, anterior leaflet extension, and coronary revascularization. Occasionally, surgical correction of concomitant lesions of the aortic valve and/or fibrous  subaortic stenosis can be performed , 16.In experienced centers, long-term surgical results are excellent. More than 90% of patients who undergo surgery are subsequently asymptomatic and can lead a normal life. Post-operative complications include atrioventricular block, ventricular septal defect, and aortic regurgitation, and have a lower frequency for experienced surgeons. Nevertheless, surgical myectomy causes left bundle branch block in many cases, and therefore, patients with preexistent right bundle branch should be informed of a high risk of requiring a pacemaker post-operatively . ASA mayASA is a minimally invasive catheter-based technique for achieving septal reduction first reported by Sigwart in 1995 . The proThe long-term results from a multinational ASA registry show that 89% of patients after ASA were in NYHA class 1 or 2, the mean decrease of LVOTO was 76%, and the 30-day mortality rate was 1% . Indeed,Long-term benefits include reductions in mitral regurgitation and in LV end-diastolic pressure, reduced left atrial pressure and size, regression of LV hypertrophy, and relief of pulmonary hypertension . Septal There is no current or completed randomized trial comparing surgical myectomy vs ASA and all comparisons are based on the results of retrospective investigations or meta-analyses of observational studies. Unfortunately, a randomized clinical trial assessing outcome appears unfeasible, based on sample power calculations . Thus, eBoth surgical myectomy and ASA may provide substantial symptomatic improvement, increase exercise capacity, and relieve LVOTO . In oldeIn each patient with symptomatic, obstructive HCM, the optimal therapeutic choice should be made on an individual basis with a multifactorial approach. A preliminary assessment of septal anatomy and the mitral valve in order to exclude the need for surgical treatment is mandatory, due to the intrinsic limitation of ASA and the risk of perforation. Likewise, the risk of conduction blocks requiring permanent pacemaker implantation with ASA and surgery should be considered based on the ECG at presentation , 5. ASA Whenever possible, a shared decision-making approach should always be pursued, discussing the risks and benefits of each approach, then understanding the needs and preferences of the individual patient. In order to choose the best-personalized treatment, it is crucial that the entire decision process is carried out with a multidisciplinary approach by a cardiomyopathy team working in dedicated centers of excellence .The concept of “heart team,” a team of clinical or non-invasive cardiologists, cardiac surgeons, and interventional cardiologists, has shown in recent years to improve the decision between angioplasty and surgery in multivessel coronary artery disease or between percutaneous and surgical to face the decision-making of aortic stenosis . SimilarIn summary, surgical myectomy and ASA are both effective options for management of LVOTO in HCM patients whose symptoms are refractory to pharmacological treatment. Optimizing efficacy while reducing pacemaker dependency and improving long-term survival is the ultimate goal of both procedures. In the absence of randomized trials comparing the two methods, the best treatment for each individual patient should be determined by a “Cardiomyopathy Team” with expertise in both procedures Table . The cho


Dynamic measures of physical resilience—the ability to resist and recover from a challenge—may be informative of biological age far prior to overt manifestations such as age-related diseases and geriatric syndromes . If true, physical resilience at younger or middle ages may be predictive of future healthspan and lifespan, and provide a unique paradigm in which interventions targeting the fundamental biology of aging can be tested. This seminar will discuss research on the development of clinically relevant measures of physical resilience in mice, including anesthesia, surgery, and cytotoxic drugs. It will further highlight how these measures compare between young, middle-aged, and older mice, and how mid-life resilience relates to later-life healthspan and even lifespan. Finally, it will provide insight into whether interventions targeting the biology of aging can modify physical resilience in mice.


Exploration of the healthcare journey post-stroke is incomplete without acknowledging the crucial role of family caregivers. With limited literature documenting the role of caregivers in the healthcare journey post-stroke, we aimed to describe the healthcare experiences of family caregivers and stroke survivors across different caregiver identities in Singapore.We conducted a qualitative descriptive study involving semi-structured interviews with transcripts analysed using thematic analysis. 26 stroke survivors and 35 family caregivers purposively sampled from multiple settings.Findings were summarized into seeking care and experience of healthcare encounters. Seeking care comprised of the following themes: factors influencing seeking care, decision to seek care and role of caregiver in seeking care. Experience of healthcare encounters comprised of the following themes: service around the patient, service with care and role of caregiver in healthcare encounters.Multi-dimensional role of caregivers in healthcare experience emerged as a major finding. Unique to our Asian context, as per the participants’ accounts, family caregivers seemed to be central in healthcare decision-making for stroke survivors, with adult-child caregivers commonly reported being engaged in collaborative decision-making. While spousal caregivers preferred a relational healthcare experience, adult-child caregivers preferred a transactional one. Practical implications include equipping caregivers with skillset to make healthcare decisions, provision of supportive decision-making environment for caregivers and reinforcing communication aspects in the medical, nursing and allied healthcare curriculum to improve healthcare experience.The online version contains supplementary material available at 10.1186/s12883-021-02463-7. Exploration of the healthcare journey post-stroke is incomplete without acknowledging the crucial role of family caregivers in providing unfading support and care for their loved ones. After surviving acute stroke event, stroke survivors face challenges on multiple fronts with significant physical, emotional, and cognitive impairments, with up to 74 % requiring someone, often a family member, to aid with activities of daily living (ADL) , and morrelatives, partners, friends, or neighbors who provide help because of a personal relationship and who provide personal and medically oriented care” [Family caregivers, also known as informal caregivers, have been previously defined as “ed care” . They ared care” . Caregived care” . About 5ed care” , 7. Desped care” , family ed care” . While ted care” –13, thered care” . While ted care” , there iWe need to unpack the intersection of caregiving and healthcare experience to further establish caregivers’ position within the healthcare system, which would guide the provision of tailored support resulting in favourable stroke survivor-caregiver dyadic outcomes. From a quantitative perspective, researchers have examined the role of caregivers in health services utilization post-stroke, with studies reporting caregiver availability , co-resiOn the qualitative front, a study explored stroke survivors’ and their caregivers’ perspectives on factors associated with seeking acute care services post-stroke concluding rehospitalizations to be multi-factorial . A meta-We adopted a qualitative descriptive study design involving semi-structured interviews with stroke survivors and family caregivers . Our stufirst line of support” with the community and government stepping in where necessary [ Singapore is a small island country with a total population of around 5.64 million. Being a multi-ethnic nation, it is comprised of Chinese (74.3 %), Malays (13.4 %), Indians (9.0 %), and other ethnicities (3.2 %) . Singapoecessary . The eligibility criteria for stroke survivors were Singaporean or permanent resident, at least 21 years and above at the time of recruitment, stroke being diagnosed by a clinician and/or supported by brain imaging and able to participate in the interview. For caregivers, we included individuals aged 21 years and above, who were either an immediate family member, extended family member or friend, were recognized as the main person offering care and taking responsibility for the patient, as recognized by the patient and not paid for caregiving. Paid or professional caregivers and those refusing to audio-record the interview were excluded from the study. Stroke survivors and family caregivers were purposively sampled across different caregiver identities . Recruitment was conducted across 3 recruitment sites, namely, outpatient rehabilitation setting, outpatient clinic setting and support organization for stroke survivors and their caregivers. Fifty interviews were conducted involving 61 participants (35 caregivers and 26 stroke survivors) from October 2018 to February 2019, at which point thematic saturation was reached. The interview guide for both caregivers and stroke survivors is detailed in Supplementary File We followed Braun and Clarke’s guidance on conducting thematic analysis which comprised of the following six steps: familiarizing ourselves with our data, generating initial codes, searching for themes, reviewing of themes, defining and naming themes and producing the report . To explWe used the parallel criteria by Lincoln and Guba –33 to guWe summarized our findings of healthcare experience post-stroke across two categories: seeking care and experience of healthcare encounters. Within the category of seeking care, following themes were coded: factors influencing seeking care with sub-themes of financial, and structural factors; decision to seek care with sub-themes of caregiver decides, and not one person’s decision to make; and role of caregiver in seeking care with sub-themes of recognize symptoms, coordinate care and accompanying to healthcare appointments. Within the category of experience of healthcare encounters, following themes were coded: service around the patient with sub-themes of patient choice or preference, and dignity and respect; service with care with sub-themes of communication during a healthcare encounter, trust in the healthcare system and personal touch experienced during a healthcare encounter; and role of caregiver in healthcare encounters with sub-themes of advocate for the stroke survivor, and active participant in the healthcare encounter Fig. .The sample comprised of 35 caregivers and 26 stroke survivors. . Adult-child caregivers were most commonly reported as being in collaborative healthcare seeking decisions. Participants reported three types of shared decision making arrangements: caregiver with a healthcare provider, caregiver with stroke survivor, and caregiver with inputs from other family caregivers. Healthcare providers were mostly part of the decision to seek outpatient care services, whereas the stroke survivor was part of the decision to continue rehabilitation services. Other family members were involved in the decision to seek care based on the caregiving arrangement. Shared caregiving arrangements with distributed caregiving responsibilities, commonly observed in adult-child caregivers, meant they would often discuss and come to a conclusion for service seeking.The main sub-themes under this theme were recognizing symptoms, coordinating care, and accompanying the stroke survivor for the healthcare appointments.limping on the left side”, “he is different”, “cannot stand and she cannot move her hand” and so forth.Spousal caregivers described recognizing symptoms more commonly as compared to adult-child caregivers. Most of the shared accounts detailed the stroke survivor’s symptoms related to the index stroke event, such as, “Adult-child caregivers were more commonly involved in the role of coordinating care for their stroke survivors. Efforts to coordinate care across different care settings were reported as challenging by some, with little room for healthcare professionals to accommodate. While the caregivers reported coordinating on their end and taking turns to go to these multiple appointments, it was stressful and took a toll on a few.Along with the subtheme of coordinating care, this theme of accompanying the stroke survivors for healthcare appointments was more commonly reported by adult-child caregivers as compared to spousal caregivers.Only the Polyclinic is a bit like buying a lottery ticket” .Both patients and caregivers opined that choice of healthcare professional is something they do not have in the public healthcare setting, both acute and outpatient care, as expressed by a stroke survivor, “Choice had another dimension within the acute care setting, which was autonomy; the participants recounted their experiences in an inpatient setting, highlighting they felt powerless in the way they were treated. They preferred to have a say in what happened to them. Participants generally described their experience in an outpatient rehabilitation setting in a more positive light, where they shared accounts of stroke survivors being central to management and therapy decisions.must see the body language”, “ read it and do your homework before coming”, “talk to people clearly” and so forth. Another dimension of this sub-theme was the lack of privacy in inpatient settings. As a stroke survivor, the individual has some physical limitations which necessitate assistance from others in ADL such as showering, hygiene, toileting, and feeding. Some of the stroke survivors felt that their privacy was not respected during such encounters. The sub-theme of dignity and respect included instances where the participants mentioned their expectations of being treated with courtesy and maintaining their dignity. Participants had certain expectations such as “Service with care theme captures the essence of softer relational dynamics that stroke survivors and caregivers experienced across different healthcare settings. This included understanding the content of the conversation with the healthcare provider, and also how the participants were spoken to. Stroke survivors and caregivers often came to these healthcare encounters with certain expectations, and when these were not met, they resulted in a negative perspective of the healthcare encounter. While sharing of information was a common thread in accounts of spousal and adult-child caregivers, spousal caregivers also valued the manner in which they were spoken to. Secondly, while adult-child caregivers had no problem understanding the content of such conversations, few of the spousal caregivers struggled.Based on past healthcare experiences, participants had their guard up mostly for inpatient setting, during their more current healthcare encounters with concerns around trusting the healthcare professionals or care received. A sibling caregiver recounted her past experiences in inpatient setting, which seemed to shape her current perspective of inpatient services. She emphasized the vulnerable state of a stroke survivor in inpatient setting, and the need to be vigilant ensuring their safety. Reported lack of trust on healthcare professionals, made a stroke survivor talk about the need to educate oneself to manage care received and how ignorance may not be the best approach to address care in an inpatient setting.We found sub-theme of communication and trust being interrelated. Communications involving limited symptom clarity and explanation from healthcare professionals seemed to result in participants having limited trust in the advice given to them. Not understanding the rationale for some diagnostic tests (which cost money) seemed to make a spousal caregiver and stroke survivor question the intention behind such healthcare decisions in an outpatient setting.The described instances of personal touch or valuing care beyond medical management, mostly occurred in a step-down inpatient setting as compared to the outpatient setting. Participants recounted instances of friendly reassurance by the healthcare professionals, participating in their celebrations like birthdays, consoling them in their unfortunate moments, helping out with financial problems  and so forth.Though advocacy could manifest in a myriad of ways, for the current analysis, to be an advocate meant always keeping the interest and well-being of their care recipient to the forefront during each healthcare encounter. This ranged from trying to make the processes of care more person-centered by giving feedback, to asking for delayed discharge from inpatient tertiary setting to prepare for the new caregiving role, to consulting the physician on clinical management of their loved ones to fighting for what the caregiver felt was best for the stroke survivor. Advocacy was mostly prominent in the rehabilitation setting, as the caregivers tried to get the best rehabilitation services for the stroke survivor.This sub-theme included instances where participants reported caregiver being involved in giving and receiving information from the healthcare provider on the stroke survivor’s behalf and participating in the consults by contributing to the management discussions, where possible. Adult-child caregivers were more active in giving and receiving information and in participating in the consults as compared to spousal caregivers. Caregivers wanted healthcare professionals to talk to them about stroke survivors’ health status, changes in health status, decisions around the change of care settings, and so forth. Some caregivers also reported wanting to be considered as a partner in the post-stroke recovery journey, for instance, provision of counselling for them to cope.We described the healthcare experiences of family caregivers and stroke survivors post-stroke across two categories of seeking care and experience of healthcare encounters. Multi-dimensional role of caregivers in healthcare experience emerged as one of the major findings, along with differences in themes between spouse and adult-child caregivers contributing new knowledge.  types of caregivers as we wanted to compare the themes across all four types of caregivers. However, our results are limited to spousal and adult-child caregivers due to limited recruitment of sibling (N=2) and other (N=2) caregivers. Our findings would potentially be transferrable across spousal and adult-child caregivers only. We did not perform member checking with our participants as we did not retain contactable information beyond the interview stage. Moreover, we did not want to inconvenience our participants considering our sample did not include healthy individuals. With the aim to describe the healthcare experiences of family caregivers and stroke survivors across different caregiver identities, we highlighted the multi-dimensional role of caregivers in the post-stroke healthcare experience. Unique to Asian context, as per the participants’ accounts, family caregivers seemed to play a central role in healthcare seeking decisions for stroke survivors. For adult-child caregivers, collaborative decision-making with inputs from multiple stakeholders was commonly reported. While spousal caregivers preferred the relational aspects of healthcare encounters, for adult-child caregivers, healthcare encounters were mainly transactional involving their active participation. Differences in healthcare experiences across different caregiver identities should be incorporated into tailoring a healthcare experience suited for the type of end-users. Other practical implications would be acknowledging caregivers as partners in post-stroke healthcare journey, provision of training and supportive decision-making environment for caregivers, reinforcing communication aspects in the medical, nursing and allied healthcare curriculum to improve experience of healthcare encounters and build trust between the healthcare professional and stroke survivor-caregiver dyads.Additional file 1.Additional file 2.


Macrophages fulfill central functions in systemic iron metabolism and immune response. Infiltration and polarization of macrophages in the tumor microenvironment is associated with differential cancer prognosis. Distinct metabolic iron and immune phenotypes in tumor associated macrophages have been observed in most cancers. While this prompts the hypothesis that macroenvironmental manifestations of dysfunctional iron metabolism have direct associations with microenvironmental tumor immune response, these functional connections are still emerging. We review our current understanding of the role of macrophages in systemic and microenvironmental immune response and iron metabolism and discuss these functions in the context of cancer and immunometabolic precision therapy approaches. Accumulation of tumor associated macrophages with distinct iron pathologies at the invasive tumor front suggests an “Iron Curtain” presenting as an innate functional interface between systemic and microenvironmental iron metabolism and immune response that can be harnessed therapeutically to further our goal of treating and eliminating cancer. Defining patient prognosis, potential precision therapeutic avenues, and ultimately survival outcomes on the basis of metabolism is complicated by the need to integrate macroenvironmental and microenvironmental processes and multi-cellular metabolic systems interactions. Systemic metabolism establishes a unique profile of metabolites in the tumor microenvironment (TME), but distribution of these metabolites in the TME and their characterization is complicated by the multi-cellular dynamic composition of the tumor that introduces spatial heterogeneity of the metabolite distribution due to inter-cellular competition for metabolites that can promote tumor growth and hinder effective anti-tumor responses –5. This Of the various cells involved in cancer, macrophages play a central role in systemic and microenvironmental metabolism that has prominent effects on immune response in cancer. Tumor associated macrophages (TAMs) are implicated in all stages of cancer from tumorigenesis, to metastasis outgrowth, and therapy response as they plastically change their immune response according to local and systemic cues , 9. MetaMacrophages are involved in controlling iron import, export, and storage. These functions are regulated post-transcriptionally. mRNA-binding iron regulatory proteins 1 and 2 (IRP1 and IRP2) mediate cellular iron uptake, transport, storage and utilization in macrophages and hepatocytes . IRPs bivia specific cell surface receptors (3+) to ferrous iron (Fe2+) and transported through DMT-1 into the cytosol for ferritin storage, metabolic cofactor processes, or export through ferroportin (FPN), the cellular iron exporter  enter the macrophage eceptors . The traeceptors –18. Simieceptors , are preeceptors . NTBI caeceptors . NTBI caexporter .via erythrophagocytosis. RBCs phagocytized by the macrophage will be degraded, iron will be released from heme in the phagolysosome by heme oxygenase 1 (HO-1), transported to the cytosol of the macrophage, and processed for storage or recycling (Macrophages recycle heme iron from phagocytosis of senescent erythrocytes. Senescent red blood cells (RBCs) present cell surface markers to be recognized by macrophage scavenger receptors for phagocytosis. CD91 and CD163 are two scavenger receptors expressed at high levels on the surface of the macrophage. CD91 binds hemopexin-bound heme iron while CD163 bind both free iron and haptoglobin-hemoglobin complexed iron . RBCs arecycling . NTBI caMacrophages store iron in ferritin. Ferritin is normally found within cells but can also be found in plasma. Ferritin is an iron storage protein complex consisting of 24 molecules of light (FTL) and/or heavy (FTH) chains. Extracellular ferritin can bind cell surface ferritin receptors, mainly including heavy chain H-ferritin receptor T cell immunoglobin and mucin domain-2 and light chain L-ferritin receptor scavenger receptor member 5, mediate the uptake of ferritin-bound iron . After uIron is regulated systemically by specific organs including the liver, spleen, and bone marrow. Tissue-specific macrophage populations are present within these organs as distinct phenotypic subsets . These rThe liver is a major center for iron regulation. Hepatic hepcidin production regulates systemic iron export by promoting the internalization of the iron exporter FPN on macrophages and other cells, lowering circulating NTBI concentrations . This leThe red-pulp macrophages of the spleen filter the blood of senescent erythrocytes acting as a quality control mechanism to regulate circulating RBCs and plays important roles during inflammation by serving as a depot of immune cells. Splenic macrophages rapidly clear senescent RBCs from the blood that do not express the CD47 “don’t eat me” cell surface signaling molecule and recycle the heme iron they contain. The extracted NTBI is trafficked within red pulp macrophages to be stored in ferritin, utilized by the mitochondria, or exported to other organs, such as the bone marrow.In the bone marrow, erythroid island macrophages express high levels of iron regulation protein machinery including TfR, HO-1, and FPN to support RBC heme production . Osteoclvia erythropoietin, hypoxia signaling, mitochondrial respiration and DNA synthesis, while avoiding toxicity from free iron , analysis of iron metabolism genes, FPN, ferritin light and heavy chains, IRP2, and TfR1, revealed that these genes are all highly expressed in RCC, similar to other cancers, and TfR1 expression is used as a biomarker of RCC and is associated with worse survival outcomes . Iron levia hepcidin signaling  . AML is The above studies provide evidence supporting the central role of iron in tumor growth that is regulated in the microenvironment by macrophages. However, it remains unknown whether changes in iron metabolism stimulate changes in immune status and response, or whether changes in immune status effect macrophage iron handling. Further, it is still unknown whether these metabolic and immunologic responses arise from microenvironmental cues, or if systemic changes in iron metabolism and immune response dictate the iron handling and immune response of TAMs locally. We can derive some insight into these mechanisms by examining therapeutics targeting either iron metabolism or immunity and evaluate their reciprocal effects. Tumor response to drugs such as iron-depleting chelators or iron accumulating nanoparticles can be evaluated to investigate the role of macrophages in transmitting systemic metabolic cues to the tumor-immune microenvironment. Similarly, tumor metabolism modulates immunotherapy response, and given the previously mentioned disruptions in immune cell signaling likely has effects on macrophage iron metabolism both systemically and in the tumor microenvironment such as shown schematically in via a variety of mechanisms, involving inhibition of iron-dependent processes via their role as enzymatic co-factors, catalysts for reactive species generation, and others , deferiprone (DFP) and investigational chelators such as EC1 tropolone, have been shown to inhibit cancer cell growth d others , 67. HerIron chelators have been shown to alter iron metabolism, macrophage polarization, and immune signaling. Supporting these effects in cancer, DFO administration decreases iron availability from gastric cancer tissue slice cultures, reduces viability of cancer cells, and leads to high iron efflux by decreasing ferritin expression in the TME and TAMs . DFO alsin vivo observation of the “Iron curtain” which defined a new prognostic biomarker of macrophage iron handling associated with their spatial infiltration and cancer therapy response.DFP is another FDA approved small molecule iron chelator prescribed in cases of iron overload. The mechanism of action of deferiprone is similar to DFO, but the two agents different in that DFO chelates extracellular iron while DFP is an intracellular iron chelator. This allows DFP to mobilize cellular iron which is likely related to its effects on cancer cell proliferation. The efficacy of DFP has also been evaluated in the context of macrophage iron accumulation. Macrophages sequester iron as hemosiderin, ferritin protein aggregates, and are known as hemosiderin laden macrophages (HLM) to prevent depletion of iron and maintain levels of cytotoxic free iron. This ability of macrophages to store and metabolize iron puts them in a position to be used as putative iron reservoirs that can be exploited by tumor cells to promote their growth. In vivo treatment of Myc-CaP and TRAMP-C2 mice models of prostate cancer with DFP led to a significant anti-tumor response that was directly proportional to the amount of iron found in tumor, tumor associated macrophages and peripheral macrophages of the liver and spleen as detected by immunopathology and MRI . ImportaSupporting the role of macrophages in providing iron to support tumor growth, the iron chelator, EC1 was investigated. EC1 is a thiosemicarbazone chelator with a tridentate binding unit that ensures high affinity iron binding. The role of macrophage secreted iron was examined in renal cell carcinoma cell lines and patient samples of tumor progression by applying this novel chelation approach . These avia chelation and evaluate how macrophages handle increases in systemic iron concentrations in the tumor microenvironment.The above studies highlight the ability of systemically administered iron chelators to interfere with the iron-regulating functions of macrophages, which has complementary effects on microenvironmental immune response and tumor growth. As counterpoint to these studies, we can consider effects of iron accumulation rather than depletion via induction of HO-1, resulting in tolerance developing, where the presence of tumor cells is tolerated  is a key regulator of monocyte function that drives the recruitment of macrophages to the TME and promotes their differentiation to pro-tumorigenic TAMs –81. Precvia cellular phagocytosis, anti-CD47 immunotherapy likely effects tumor iron metabolism. This has been investigated by Daldrup-Link and coworkers where combination of doxorubicin and CD47 mAb significantly inhibited tumor growth and improved survival in a manner proportional to the increase in iron metabolism that was detected by increases in TAM iron using histology and MRI , present on macrophages and other phagocytic cells that inhibits phagocytosis when activated. Monoclonal antibodies against CD47 (CD47 mAb) inhibit the interaction between SIRPα and CD47 effectively blocking the “don’t eat me” signal to activate TAMs and promote macrophage phagocytosis of, for example, of malignant osteosarcoma cells , and sel and MRI . Outside and MRI –93. Thisper se has not been an area of focus in adaptive immunotherapy to date, research on T lymphocyte biology have noted that iron metabolism plays an important role in T cell migration and activation throughout the body  is frequently overexpressed on tumor cells enabling their escape from immune surveillance. Monoclonal antibodies blocking PD-L1/PD-1, so called immune checkpoint blockade inhibitors (ICB), have been clinically shown to have efficacy in patients with a variety of cancers by activating T lymphocytes , 95. Whithe body , 96, 97.survival . Considesurvival , 100.via iron catalyzed peroxidation of polyunsaturated lipids and its’ regulation by factor, such as system Xc- and the glutathione peroxidase 4 enzyme (GPX4) which maintains cellular redox homeostasis  which accumulate iron, accumulation while release of iron to cancer cells by M2 polarized macrophages supports the iron-addicted metabolic program of the cancer cells within the TME.To fully establish the role of macrophage iron metabolism in cancer, however, more research is needed to answer pressing questions such as: How spatial heterogeneity in tumor microenvironment influences the molecular networks that allow iron exchange between cancer cells and macrophages? How iron flux in macrophages changes their communication with other immune cell and stromal components? How systemic metabolic dynamics of iron alters macrophage plasticity longitudinally over the many complex steps of tumorigenesis, cancer progression, metastasis, and therapeutic response? In the future we will tackle these multiscale phenomena from a bench-to-beside approach, making use of translational advances in cytology, bioinformatics, and imaging to reveal new ways to therapeutically harness these targets and translate these insights to the clinic. Our insights here support these further investigations into the crosstalk between iron metabolism and immune response and strongly warrants further development of anti-cancer therapies that target this immunometabolic axis.AD and AL conducted literature searches, prepared figures, and wrote the article. All authors contributed to the article and approved the submitted version.We gratefully acknowledge funding from the Carol M. Baldwin Breast Cancer Research Fund, Stony Brook School of Medicine Departments of Radiology and Pharmacological Sciences, and the Bahl Center for Metabolomics and Imaging at the Stony Brook Cancer Center.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.