Distinct T cell subsets in adipose tissue are associated with obesity.

Adipose tissue inflammation is a driving factor for the development of obesity-associated metabolic disturbances, and a role of adipose tissue T cells in initiating the pro-inflammatory signaling is emerging. However, data on human adipose tissue T cells in obesity are limited, reflected by the lack of phenotypic markers to define tissue-resident T cell subsets. In this study, we performed a deep characterization of T cells in blood and adipose tissue depots using multicolor flow cytometry and RNA sequencing. We identified distinct subsets of T cells associated with obesity expressing the activation markers, CD26 and CCR5, and obesity-specific genes that are potentially engaged in activating pro-inflammatory pathway, including ceramide signaling, autophagy, and IL-6 signaling. These findings increase our knowledge on the heterogeneity of T cells in adipose tissue and on subsets that may play a role in obesity-related pathogenesis.

Adipocyte-derived lactate is a signalling metabolite that potentiates adipose macrophage inflammation via targeting PHD2.

Adipose tissue macrophage (ATM) inflammation is involved with meta-inflammation and pathology of metabolic complications. Here we report that in adipocytes, elevated lactate production, previously regarded as the waste product of glycolysis, serves as a danger signal to promote ATM polarization to an inflammatory state in the context of obesity. Adipocyte-selective deletion of lactate dehydrogenase A (Ldha), the enzyme converting pyruvate to lactate, protects mice from obesity-associated glucose intolerance and insulin resistance, accompanied by a lower percentage of inflammatory ATM and reduced production of pro-inflammatory cytokines such as interleukin 1ß (IL-1ß). Mechanistically, lactate, at its physiological concentration, fosters the activation of inflammatory macrophages by directly binding to the catalytic domain of prolyl hydroxylase domain-containing 2 (PHD2) in a competitive manner with α-ketoglutarate and stabilizes hypoxia inducible factor (HIF-1α). Lactate-induced IL-1ß was abolished in PHD2-deficient macrophages. Human adipose lactate level is positively linked with local inflammatory features and insulin resistance index independent of the body mass index (BMI). Our study shows a critical function of adipocyte-derived lactate in promoting the pro-inflammatory microenvironment in adipose and identifies PHD2 as a direct sensor of lactate, which functions to connect chronic inflammation and energy metabolism.

Correlation of insulin resistance with neutrophil to lymphocyte ratio and serum ferritin in male patients of metabolic syndrome.

OBJECTIVE: To determine the correlation of insulin resistance with neutrophil-to-lymphocyte ratio and serum ferritin, and to evaluate whether NLR and serum ferritin can predict insulin resistance in metabolic syndrome. METHODS: The cross-sectional analytical study was conducted at the University of Health Sciences, Lahore, Pakistan, from July 2016 to 2019, and comprised male patients of metabolic syndrome and healthy controls. The correlation involving insulin resistance, serum ferritin and neutrophil-to-lymphocyte ratio was determined. Data was analysed using SPSS 22. RESULTS: Of the 210 subjects, 160(76.2%) were cases with a median age of 45 years (interquartile range: 39-50 years), and 50(23.8%) were controls with a median age of 41 years (interquartile range: 35-50 years). Serum ferritin, alanine aminotransferase, total neutrophil count, lymphocyte count and neutrophil-to-lymphocyte ratio were significantly higher among the cases than the controls (p<0.05). Significant positive correlation of insulin resistance was observed with serum ferritin and neutrophil-to-lymphocyte ratio (p<0.05)) among the cases. Neutrophil-to-lymphocyte ratio significantly predicted insulin resistance among the cases (p<0.05). Conclusion: Neutrophil-to-lymphocyte ratio was fund to be a significant predictor of insulin resistance in metabolic syndrome.

Distinct Lipidomic Signatures in People Living With HIV: Combined Analysis of ACTG 5260s and MACS/WIHS.

CONTEXT: Disentangling contributions of HIV from antiretroviral therapy (ART) and understanding the effects of different ART on metabolic complications in persons living with HIV (PLHIV) has been challenging. OBJECTIVE: We assessed the effect of untreated HIV infection as well as different antiretroviral therapy (ART) on the metabolome/lipidome. METHODS: Widely targeted plasma metabolomic and lipidomic profiling was performed on HIV-seronegative individuals and people living with HIV (PLHIV) before and after initiating ART (tenofovir/emtricitabine plus atazanavir/ritonavir [ATV/r] or darunavir/ritonavir [DRV/r] or raltegravir [RAL]). Orthogonal partial least squares discriminant analysis was used to assess metabolites/lipid subspecies that discriminated between groups. Graphical lasso estimated group-specific metabolite/lipid subspecies networks associated with the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Correlations between inflammatory markers and metabolites/lipid subspecies were visualized using heat maps. RESULTS: Of 435 participants, 218 were PLHIV. Compared to HIV-seronegative individuals, ART-naive PLHIV exhibited higher levels of saturated triacylglycerols/triglycerides (TAGs) and 3-hydroxy-kynurenine, lower levels of unsaturated TAGs and N-acetyl-tryptophan, and a sparser and less heterogeneous network of metabolites/lipid subspecies associated with HOMA-IR. PLHIV on RAL vs ATV/r or DRV/r had lower saturated and unsaturated TAGs. Positive correlations were found between medium-long chain acylcarnitines (C14-C6 ACs), palmitate, and HOMA-IR for RAL but not ATV/r or DRV/r. Stronger correlations were seen for TAGs with interleukin 6 and high-sensitivity C-reactive protein after RAL vs ATV/r or DRV/r initiation; these correlations were absent in ART-naive PLHIV. CONCLUSION: Alterations in the metabolome/lipidome suggest increased lipogenesis for ART-naive PLHIV vs HIV-seronegative individuals, increased TAG turnover for RAL vs ATV/r or DRV/r, and increased inflammation associated with this altered metabolome/lipidome after initiating ART. Future studies are needed to understand cardiometabolic consequences of lipogenesis and inflammation in PLHIV.

Insulin Increases Adipose Adiponectin in Pregnancy by Inhibiting Ubiquitination and Degradation: Impact of Obesity.

CONTEXT: Circulating adiponectin levels are decreased in pregnant women with obesity or gestational diabetes, and this is believed to contribute to the insulin resistance and increased risk of fetal overgrowth associated with these conditions. However, the molecular mechanisms regulating adiponectin secretion from maternal adipose tissues in pregnancy are poorly understood. OBJECTIVE: We tested the hypothesis that obesity in pregnancy is associated with adipose tissue insulin resistance and increased adiponectin ubiquitination and degradation, caused by inflammation and endoplasmic reticulum (ER) stress. METHODS: Visceral adipose tissues were collected from lean and obese pregnant humans and mice. Total and ubiquitinated adiponectin, and markers of inflammation, ER stress, and insulin resistance were examined in adipose tissues. The role of insulin, inflammation, and ER stress in mediating adiponectin ubiquitination and degradation was examined using 3T3L-1 adipocytes. RESULTS: Obesity in pregnancy is associated with adipose tissue inflammation, ER stress, insulin resistance, increased adiponectin ubiquitination, and decreased total abundance of adiponectin. Adiponectin ubiquitination was increased in visceral fat of obese pregnant women as compared to lean pregnant women. We further observed that insulin prevents, whereas ER stress and inflammation promote, adiponectin ubiquitination and degradation in differentiated 3T3-L1 adipocytes. CONCLUSION: We have identified adiponectin ubiquitination as a key mechanism by which obesity diminishes adiponectin secretion in pregnancy. This information will help us better understand the mechanisms controlling maternal insulin resistance and fetal growth in pregnancy and may provide a foundation for the development of strategies aimed at improving adiponectin production in pregnant women with obesity or gestational diabetes.

Natural killer cell-derived exosomal miR-1249-3p attenuates insulin resistance and inflammation in mouse models of type 2 diabetes.

Natural killer (NK) cells have been suggested to be associated with type 2 diabetes by regulating systemic inflammation. However, the mechanism by which NK cells regulate insulin sensitivity remains unknown. This study shows that NK-derived exosomes from lean mice attenuate obesity-induced insulin resistance and inflammation in mice of type 2 diabetes. Moreover, lean NK-derived exosomes enhance insulin sensitivity and relieve inflammation in adipocytes and hepatocytes. MiR-1249-3p, which is significantly upregulated in lean NK-derived exosomes, can be transferred from NK cells to adipocytes and hepatocytes via exosomes. NK-derived exosomal miR-1249-3p dramatically induces cellular insulin sensitivity and relieves inflammation. Mechanistically, exosomal miR-1249-3p directly targets SKOR1 to regulate the formation of ternary complex SMAD6/MYD88/SMURF1, which mediates glucose homeostasis by suppressing the TLR4/NF-κB signaling pathway. This study reveals an emerging role for NK-derived exosomal miR-1249-3p in remission of insulin resistance, and provides a series of potential therapeutic targets in type 2 diabetes.

Time-Restricted Feeding Restores Obesity-Induced Alteration in Adipose Tissue Immune Cell Phenotype.

Studies suggest that time-restricted feeding (TRF) may prevent obesity and its commodities. At present, little is known about how TRF impacts immune cells, and whether such an effect is linked to altered metabolic parameters under condition of a high-fat diet (HFD)-induced obesity. To address these issues, we conducted a study in which we determined whether TRF has therapeutic efficacy against weight gain, adiposity, as well as associated immune cell disturbance found in obese mice. Six-week-old male C57BL/6 mice were fed a low-fat diet (LFD) or HFD ad libitum for six weeks, after which time a subgroup of HFD mice was switched to the 10 h TRF paradigm (HFD-TRF) for additional eight weeks. We found that TRF intervention reduced HFD-induced weight gain. Even with comparable fat mass and mean adipocyte area, the HFD-TRF group had lower mRNA levels of proinflammatory cytokine Tnfα and chemokine Ccl8, along with reduced numbers of adipose tissue macrophages (ATM), CD11c+ ATM, and CD8+ T cell compared to the HFD group, while maintaining CD8+ to CD4+ ratio at levels similar to those in the LFD group. Furthermore, TRF intervention was effective in improving glucose tolerance and reducing HOMA-IR. Taken together, our findings suggest that TRF restores the obesity-induced alteration in immune cell composition, and this effect may in part contribute to health benefits (including insulin sensitivity) of practicing TRF.

Mathematical Modeling of Severe Acute Respiratory Syndrome Coronavirus 2 Infection Network with Cytokine Storm, Oxidative Stress, Thrombosis, Insulin Resistance, and Nitric Oxide Pathways.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a systemic disease affecting not only the lungs but also multiple organ systems. Clinical studies implicate that SARS-CoV-2 infection causes imbalance of cellular homeostasis and immune response that trigger cytokine storm, oxidative stress, thrombosis, and insulin resistance. Mathematical modeling can offer in-depth understanding of the SARS-CoV-2 infection and illuminate how subcellular mechanisms and feedback loops underpin disease progression and multiorgan failure. We report here a mathematical model of SARS-CoV-2 infection pathway network with cytokine storm, oxidative stress, thrombosis, insulin resistance, and nitric oxide (NO) pathways. The biochemical systems theory model shows autocrine loops with positive feedback enabling excessive immune response, cytokines, transcription factors, and interferons, which can imbalance homeostasis of the system. The simulations suggest that changes in immune response led to uncontrolled release of cytokines and chemokines, including interleukin (IL)-1ß, IL-6, and tumor necrosis factor α (TNFα), and affect insulin, coagulation, and NO signaling pathways. Increased production of NETs (neutrophil extracellular traps), thrombin, PAI-1 (plasminogen activator inhibitor-1), and other procoagulant factors led to thrombosis. By analyzing complex biochemical reactions, this model forecasts the key intermediates, potential biomarkers, and risk factors at different stages of COVID-19. These insights can be useful for drug discovery and development, as well as precision treatment of multiorgan implications of COVID-19 as seen in systems medicine.

Distinct mechanisms involving diacylglycerol, ceramides, and inflammation underlie insulin resistance in oxidative and glycolytic muscles from high fat-fed rats.

This study investigated whether oxidative and glycolytic rat skeletal muscles respond differently to a high-fat (HF) sucrose-enriched diet with respect to diacylglycerol (DAG) and ceramides accumulation, protein kinase C (PKC) activation, glucose metabolism, and the expression of inflammatory genes. HF diet (8 weeks) suppressed insulin-stimulated glycogen synthesis and glucose oxidation in soleus (Sol), extensor digitorum longus (EDL) and epitrochlearis (Epit) muscles. However, DAG and ceramides levels increased in Sol and EDL, but not in Epit muscles of HF-fed rats. Additionally, membrane-bound PKC-delta and PKC-theta increased in Sol and EDL, whereas in Epit muscles both PKC isoforms were reduced by HF diet. In Epit muscles, HF diet also increased the expression of tumor necrosis factor-α (TNF-α) receptors (CD40 and FAS), toll-like receptor 4 (TLR4), and nuclear factor kappa light polypeptide gene enhancer in B cells (NF-kB), whereas in Sol and EDL muscles the expression of these inflammatory genes remained unchanged upon HF feeding. In conclusion, HF diet caused DAG and ceramides accumulation, PKC activation, and the induction of inflammatory pathways in a fiber type-specific manner. These findings help explain why oxidative and glycolytic muscles similarly develop insulin resistance, despite major differences in their metabolic characteristics and responsiveness to dietary lipid abundance.

Insulin signaling establishes a developmental trajectory of adipose regulatory T cells.

Systematic characterizations of adipose regulatory T (Treg) cell subsets and their phenotypes remain uncommon. Using single-cell ATAC-sequencing and paired single-cell RNA and T cell receptor (TCR) sequencing to map mouse adipose Treg cells, we identified CD73hiST2lo and CD73loST2hi subsets with distinct clonal expansion patterns. Analysis of TCR-sharing data implied a state transition between CD73hiST2lo and CD73loST2hi subsets. Mechanistically, we revealed that insulin signaling occurs through a HIF-1α-Med23-PPAR-γ axis to drive the transition of CD73hiST2lo into a CD73loST2hi adipose Treg cell subset. Treg cells deficient in insulin receptor, HIF-1α or Med23 have decreased PPAR-γ expression that in turn promotes accumulation of CD73hiST2lo adipose Treg cells and physiological adenosine production to activate beige fat biogenesis. We therefore unveiled a developmental trajectory of adipose Treg cells and its dependence on insulin signaling. Our findings have implications for understanding the dynamics of adipose Treg cell subsets in aged and obese contexts.

Adipose Tissue Dendritic Cells: Critical Regulators of Obesity-Induced Inflammation and Insulin Resistance.

Chronic inflammation of the adipose tissue (AT) is a critical component of obesity-induced insulin resistance and type 2 diabetes. Adipose tissue immune cells, including AT macrophages (ATMs), AT dendritic cells (ATDCs), and T cells, are dynamically regulated by obesity and participate in obesity-induced inflammation. Among AT resident immune cells, ATDCs are master immune regulators and engage in crosstalk with various immune cells to initiate and regulate immune responses. However, due to confounding markers and lack of animal models, their exact role and contribution to the initiation and maintenance of AT inflammation and insulin resistance have not been clearly elucidated. This paper reviews the current understanding of ATDCs and their role in obesity-induced AT inflammation. We also provide the potential mechanisms by which ATDCs regulate AT inflammation and insulin resistance in obesity. Finally, this review offers perspectives on ways to better dissect the distinct functions and contributions of ATDCs to obesity.

Protective Effect of Jiang Tang Xiao Ke Granules against Skeletal Muscle IR via Activation of the AMPK/SIRT1/PGC-1α Signaling Pathway.

The Jiang Tang Xiao Ke (JTXK) granule is a classic Chinese herbal formula that has been put into clinical use in the treatment of type 2 diabetes mellitus for decades. However, whether its ability to ameliorate skeletal muscle insulin resistance (IR) is through modulation of the AMPK/SIRT1/PGC-1α signaling pathway remains unknown. Therefore, we aimed to investigate the effects of JTXK granules on IR in skeletal muscle of high-fat diet-induced diabetic mice and C2C12 cells and analyze the underlying mechanisms. In the present study, we showed that JTXK granules attenuated body weight gain, reduced body fat mass, improved body lean mass, and enhanced muscle performance of diabetic mice. JTXK granules also improved glucose metabolism and skeletal muscle insulin sensitivity and partially reversed abnormal serum lipid levels, which might be related to the regulation of the AMPK/SIRT1/PGC-1α pathway, both in skeletal muscle tissue of diabetic mice and in C2C12 cells. Furthermore, drug-containing serum of JTXK granules was capable of enhancing glucose uptake and mitochondrial respiration in C2C12 cells, and AMPKα was proven to be closely involved in this process. Taken together, these results suggest that the JTXK granule ameliorates skeletal muscle IR through activation of the AMPK/SIRT1/PGC-1α signaling pathway, which offers a novel perspective of this formula to combat IR-related metabolic diseases.

Randomized double blind clinical trial evaluating the Ellagic acid effects on insulin resistance, oxidative stress and sex hormones levels in women with polycystic ovarian syndrome.

OBJECTIVE: The design of this study was due to the report of the antioxidant properties of Ellagic acid (EA) for its evaluation on the Insulin resistance (IR), oxidative stress and sex hormones levels in women with polycystic ovarian syndrome (PCOS). METHODS: In this randomized, double-blind, placebo-controlled clinical trial, 60 patients were recruited. Patients were randomly allocated consumed a capsule containing 200 mg of EA per day (n = 30) or placebo (n = 30) for 8 weeks. The fasting blood sugar (FBS), insulin, IR, total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL), high density lipoprotein (HDL), total antioxidant capacity (TAC), Malondialdehyde (MDA), C-reactive protein (CRP), Tumor necrosis factor-alpha (TNF-α), sex hormones and anti-mullerian hormone (AMH) were measured at the beginning and end of the study. RESULT: At the end of the study, the mean of FBS, insulin, IR, TC, TG, LDL, MDA, CRP, TNF-α, total testosterone, prolactin and AMH were significantly decreased in the intervention group compared to the placebo group (P < 0.05). Also, there was a significant increase in the mean of TAC after supplementation with EA (P < 0.05). At the end of the study, no significant changes were observed in the mean of anthropometric factors, physical activity and food intake (P > 0.05). CONCLUSION: EA supplementation can be helpful as a diet supplement in women with PCOS through improvement in insulin resistance. This supplement may be used to reduce metabolic disorders in women. TRIAL REGISTRATION: This study was retrospectively (07-07-2019) registered in the Iranian website ( www.irct.ir ) for registration of clinical trials ( IRCT20141025019669N12 ).

Insulin resistance is linked to a specific profile of immune activation in human subjects.

We tested the hypothesis that a particular immune activation profile might be correlated with insulin resistance in a general population. By measuring 43 markers of immune, endothelial, and coagulation activation, we have previously shown that five different immune activation profiles may be distinguished in 150 volunteers. One of these profiles, Profile 2, characterized by CD4+ T cell senescence, inflammation, monocyte, B cell, and endothelial activation, presented elevated insulinemia, glycemia, triglyceridemia, and γ-glutamyl transferase, a marker of liver injury, in comparison with other profiles. Our data are compatible with a model in which a particular immune activation profile might favor the development of insulin resistance and metabolic syndrome. In this hypothesis, identification of this profile, that is feasible with only 3 markers with an error rate of 5%, might allow to personalize the screening and prevention of metabolic syndrome-driven morbidities as liver steatosis.

Emerging concepts in intestinal immune control of obesity-related metabolic disease.

The intestinal immune system is an important modulator of glucose homeostasis and obesity-associated insulin resistance. Dietary factors, the intestinal microbiota and their metabolites shape intestinal immunity during obesity. The intestinal immune system in turn affects processes such as intestinal permeability, immune cell trafficking, and intestinal hormone availability, impacting systemic insulin resistance. Understanding these pathways might identify mechanisms underlying treatments for insulin resistance, such as metformin and bariatric surgery, or aid in developing new therapies and vaccination approaches. Here, we highlight evolving concepts centered on intestinal immunity, diet, and the microbiota to provide a working model of obesity-related metabolic disease.

The Combination of Berberine, Tocotrienols and Coffee Extracts Improves Metabolic Profile and Liver Steatosis by the Modulation of Gut Microbiota and Hepatic miR-122 and miR-34a Expression in Mice.

Non-alcoholic-fatty liver disease (NAFLD) is spreading worldwide. Specific drugs for NAFLD are not yet available, even if some plant extracts show beneficial properties. We evaluated the effects of a combination, composed by Berberis Aristata, Elaeis Guineensis and Coffea Canephora, on the development of obesity, hepatic steatosis, insulin-resistance and on the modulation of hepatic microRNAs (miRNA) levels and microbiota composition in a mouse model of liver damage. C57BL/6 mice were fed with standard diet (SD, n = 8), high fat diet (HFD, n = 8) or HFD plus plant extracts (HFD+E, n = 8) for 24 weeks. Liver expression of miR-122 and miR-34a was evaluated by quantitativePCR. Microbiome analysis was performed on cecal content by 16S rRNA sequencing. HFD+E-mice showed lower body weight (p < 0.01), amelioration of insulin-sensitivity (p = 0.021), total cholesterol (p = 0.014), low-density-lipoprotein-cholesterol (p < 0.001), alanine-aminotransferase (p = 0.038) and hepatic steatosis compared to HFD-mice. While a decrease of hepatic miR-122 and increase of miR-34a were observed in HFD-mice compared to SD-mice, both these miRNAs had similar levels to SD-mice in HFD+E-mice. Moreover, a different microbial composition was found between SD- and HFD-mice, with a partial rescue of dysbiosis in HFD+E-mice. This combination of plant extracts had a beneficial effect on HFD-induced NAFLD by the modulation of miR-122, miR-34a and gut microbiome.

ICOS signaling limits regulatory T cell accumulation and function in visceral adipose tissue.

A unique population of Foxp3+ regulatory T cells (TRs) resides in visceral adipose tissue (VAT) that regulates adipose inflammation and helps preserve insulin sensitivity. Inducible T cell co-stimulator (ICOS) is highly expressed on effector (e)TRs that migrate to nonlymphoid tissues, and contributes to their maintenance and function in models of autoimmunity. In this study, we report an unexpected cell-intrinsic role for ICOS expression and downstream phosphoinositide 3-kinase (PI3K) signaling in limiting the abundance, VAT-associated phenotype, and function of TRs specifically in VAT. Icos-/- mice and mice expressing a knock-in form of ICOS that cannot activate PI3K had increased VAT-TR abundance and elevated expression of canonical VAT-TR markers. Loss of ICOS signaling facilitated enhanced accumulation of TRs to VAT associated with elevated CCR3 expression, and resulted in reduced adipose inflammation and heightened insulin sensitivity in the context of a high-fat diet. Thus, we have uncovered a new and surprising molecular pathway that regulates VAT-TR accumulation and function.

Liver-spleen axis in nonalcoholic fatty liver disease.

Introduction: NAFLD is often under-diagnosed, even though rates of its co-morbidities such as obesity and type2 diabetes mellitus, prominent statuses of inflammation, are significantly high. The spleen-liver axis is gaining much credit in the last years like other well-known organ axes.Areas covered: PubMed/MEDLINE was searched for relevant articles related to concomitant occurrence of NAFLD and spleen. Areas covered in this review include: (1) updated findings of spleen dimensions at ultrasonography, (2) discussion of current data on pathophysiological connections between obesity-related NAFLD and increased volume of the spleen, and (3) analysis of current immune-mediated mechanisms characterizing the so.called chronic low-grade inflammation leading to insulin resistance.Expert opinion: The advances in explaining mechanisms underlying the spleen involvement in immune regulation, coupled with research about the role of spleen in NAFLD, could impact real world outcomes through establishing better tools for a precocious diagnosis. Using both liver and spleen ultrasonography, technique largely dealt with in this review, could expand the possibility to cover an adequate diagnostic path toward NAFLD, reaching a good sensibility and specificity.

T helper 17 cells: A new actor on the stage of type 2 diabetes and aging?

Metformin improves mitochondrial function and enhances autophagy of T helper 17 cells, leading to decreased inflammation. This highlights the importance of metabolic modulation of immune cells.

Evaluation of endometrial immune status of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is described as a low-grade chronic inflammatory state. However, there are limited studies on the specific endometrial immune status of PCOS patients. Whether this endometrial immune cell pattern is intrinsic to PCOS or the consequence of PCOS-associated obesity is a subject of debate. This study retrospectively included one hundred women diagnosed with PCOS and ninety-five normal fertile controls, which further divided into four groups (normoweight PCOS; overweight PCOS; normoweight control; overweight control) based on body mass index. The percentages of endometrial CD68+ macrophages (1.97 % vs. 1.17 %; P < 0.001), CD163+ M2 macrophages (2.30 % vs. 1.83 %; P = 0.001), CD1a+ iDCs (0.044 % vs. 0.029 %; P = 0.002), CD83+ mDCs (1.72 % vs. 1.07 %; P < 0.001) and CD8+ T cells (2.82 % vs. 1.95 %; P < 0.001) were significantly higher in normoweight PCOS women than normoweight controls. The percentage of CD68+ macrophages (2.09 % vs. 1.15 %; P < 0.001) was significantly higher in overweight PCOS women compared with overweight controls. In multivariant linear regression analysis, participants' PCOS status was the main predictors of endometrial CD68+ macrophages, CD163+ M2 macrophages, CD1a+ iDCs, CD83+ mDCs and CD8+ T cells in the whole study population. Additionally, in PCOS group, positive correlations were found between endometrial CD56+ NK, CD163+ M2 macrophages and QUICKI, indicating there was an association between endometrial immune cells and insulin resistance in PCOS women. Our study suggests that women with PCOS have altered endometrial immune cells, which may reflect a state of chronic low grade inflammation. The chronic inflammation, independent of obesity, may help understand the pathophysiologic mechanisms of intrinsic PCOS.