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Background: The interactions of adipose tissue with the kidney are hypothesized to affect kidney function. Also, excessive peri-renal fat may increase the risk of cardiometabolic risk. However, the role(s) of peri-renal fat adipocytokine has never been evaluated. Objectives: To elucidate levels of adiponectin expression in peri-renal and subcutaneous adipose tissue and its determinants in human biopsied samples. Methods: A pair of subcutaneous and perirenal fat tissue samples were collected from 80 patients (men: 54; women: 26) who underwent urological operations. Subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area and peri-renal adipose tissue (RAT) volume were quantified on abdominal computed tomography. Cytokine/adipocytokine expression was evaluated by real-time semi-quantitative polymerase chain reaction (qPCR). Probability was considered significant if P < 0.05. Results: Current study evaluated determinants of plasma adiponectin levels and expression levels of adiponectin in SAT and RAT in human samples. We found that: first, plasma adiponectin levels were correlated with VAT area but not with BMI, waist circumference, SAT area, and RAT volume; second, expression levels of adiponectin in SAT were correlated with BMI, waist circumference, and SAT area but not with VAT area and RAT volume; and third, expression levels of adiponectin in RAT were correlated with all adiposity indices including BMI, waist circumference, SAT area, VAT area, and RAT volume. Conclusion: This study evaluated levels of adiponectin expression in RAT and SAT and its determinants in patients who underwent urological operation. Levels of adiponectin mRNA in RAT were negatively correlated with remote fat mass in SAT and VAT and also with local fat mass in RAT, while level of adiponectin in SAT was not correlated with RAT volume. Further studies are warranted to evaluate roles of peri-renal fat mass accumulation and its pathophysiological machineries. [ABSTRACT FROM AUTHOR]

Gender difference in obesity-associated cardiovascular complication could be derived from divergent chronic inflammation. We evaluated depot- and gender-specific regulation of the innate immune system in human adipose tissues. Pair samples were obtained from subcutaneous (SAT) and visceral adipose tissue (VAT) during elective surgery (Male: 35; Female: 27). Expressions of pro- and anti-inflammatory adipocytokines were evaluated by semi-quantitative qPCR. Adipose cell-size distribution was obtained from tissue samples fixed in osmium tetroxide and analyzed by Beckman Coulter Multisizer. Levels of adiponectin were higher in SAT and VAT of female than those of male ( P < 0.001 and P = 0.011, respectively). NLRP3, IL1β-IL18, TLR2 were comparable in SAT and VAT between genders. However, TLR4 and TLR9 were increased in female SAT and VAT and HMGB1 in female VAT. Levels of adiponectin were not correlated with mean diameter of adipocyte ( φ, μm) in SAT and VAT of male, but negatively well correlated in those of female ( r = −0.392 and r = −0.616). Such negative correlations were also observed between levels of TLR2, TLR4, and HMGB1 and φ in female. Levels of NLRP3 and IL1β were positively correlated with φ in male, but not in female. In conclusion, Innate signals were differentially expressed in male and female adipose tissues, suggesting that the depot- and gender-specific signals could be related to gender difference in chronic inflammation. © 2016 BioFactors, 42(4):397-406, 2016 [ABSTRACT FROM AUTHOR]

Recent accumulating evidence suggests that innate immunity is associated with obesity-induced chronic inflammation and metabolic disorders. Here, we show that a Toll-like receptor (TLR) protein, radioprotective 105 (RP105)/myeloid differentiation protein (MD)-1 complex, contributes to high-fat diet (HFD)-induced obesity, adipose tissue inflammation, and insulin resistance. An HFD dramatically increased RP105 mRNA and protein expression in stromal vascular fraction of epididymal white adipose tissue (eWAT) in wild-type (WT) mice. RP105 mRNA expression also was significantly increased in the visceral adipose tissue of obese human subjects relative to nonobese subjects. The RP105/MD-1 complex was expressed by most adipose tissue macrophages (ATMs). An HFD increased RP105/MD-1 expression on the M1 subset of ATMs that accumulate in eWAT. Macrophages also acquired this characteristic in coculture with 3T3-L1 adipocytes. RP105 knockout (KO) and MD-1 KO mice had less HFD-induced adipose tissue inflammation, hepatic steatosis, and insulin resistance compared with wild-type (WT) and TLR4 KO mice. Finally, the saturated fatty acids, palmitic and stearic acids, are endogenous ligands for TLR4, but they did not activate RP105/MD-1. Thus, the RP105/MD-1 complex is a major mediator of adipose tissue inflammation independent of TLR4 signaling and may represent a novel therapeutic target for obesity-associated metabolic disorders. [ABSTRACT FROM AUTHOR]

Background: Growing evidence suggests that epicardial adipose tissue (EAT) may contribute to the development of coronary artery disease (CAD). In this study, we explored gender disparities in EAT volume (EATV) and its impact on coronary atherosclerosis. Methods: The study population consisted of 90 consecutive subjects (age: 63 ± 12 years; men: 47, women: 43) who underwent 256-slice multi-detector computed tomography (MDCT) coronary angiography. EATV was measured as the sum of cross-sectional epicardial fat area on CT images, from the lower surface of the left pulmonary artery origin to the apex. Subjects were segregated into the CAD group (coronary luminal narrowing > 50%) and non-CAD group. Results: EATV/body surface area (BSA) was higher among men in the CAD group than in the non-CAD group (62 ± 13 vs. 33 ± 10 cm3/m2, p < 0.0001), but did not differ significantly among women in the 2 groups (49 ± 18 vs. 42 ± 9 cm3/m2, not significant). Multivariate logistic analysis showed that EATV/BSA was the single predictor for >50% coronary luminal narrowing in men (p < 0.0001). Predictors excluded were age, body mass index, hypertension, diabetes mellitus, and hyperlipidemia. Conclusions: Increased EATV is strongly associated with coronary atherosclerosis in men. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this report was to assess the link between macrophage polarization in epicardial adipose tissue and atherosclerosis in patients with coronary artery disease (CAD). Background: Macrophage accumulation enhances chronic inflammation in adipose tissue, but macrophage phenotypic change in human epicardial adipose tissue and its role in atherogenesis are unknown. Methods: Samples were obtained from epicardial and subcutaneous adipose tissue during elective cardiac surgery (CAD, n = 38; non-CAD, n = 40). Infiltration of M1/M2 macrophages was investigated by immunohistochemical staining with antibodies against CD11c and CD206, respectively. Expression of pro- and anti-inflammatory adipocytokines in adipose tissue was evaluated by real-time quantitative polymerase chain reaction. Results: Infiltration of macrophages and expression of pro- and anti-inflammatory cytokines were enhanced in epicardial fat of patients with CAD compared with that in non-CAD patients (p < 0.05). The ratio of M1/M2 macrophages was positively correlated with the severity of CAD (r = 0.312, p = 0.039). Furthermore, the expression of pro-inflammatory cytokines was positively correlated, and the expression of anti-inflammatory cytokines was negatively correlated with the ratio of M1/M2 macrophages in epicardial adipose tissue of CAD patients. By contrast, there was no significant difference in macrophage infiltration and cytokine expression in subcutaneous adipose tissue between the CAD and non-CAD groups. Conclusions: The ratio of M1/M2 macrophages in epicardial adipose tissue of CAD patients is changed compared with that in non-CAD patients. Human coronary atherosclerosis is associated with macrophage polarization in epicardial adipose tissue. [Copyright &y& Elsevier]

OBJECTIVE--We have provided evidence that saturated fatty acids, which are released from adipocytes Via macrophage-induced adipocyte lipolysis, serve as a naturally occurring ligand for the Toll-like receptor (TLR) 4 complex in macrophages, thereby aggravating obesity-induced adipose tissue inflammation. The aim of this study was to identify the molecule(s) activated in adipose tissue macrophages in obesity. RESEARCH DESIGN AND METHODS--We performed a cDNA microarray analysis of coculture of 3T3-L1 adipocytes and RAW264 macrophages. Cultured adipocytes and macrophages and the adipose tissue of obese mice and humans were used to examine mRNA and protein expression. RESULTS--We found that macrophage-inducible C-type lectin (Mincle; also called Clec4e and Clecsf9), a type II transmembrane C-type lectin, is induced selectively in macrophages during the interaction between adipocytes and macrophages. Treatment with palmitate, a major saturated fatty acid released from 3T3-L1 adipocytes, induced Mincle mRNA expression in macrophages at least partly through the TLR4/nuclear factor (NF)-κB pathway. Mincle mRNA expression was increased in parallel with macrophage markers in the adipose tissue of obese mice and humans. The obesity-induced increase in Mincle mRNA expression was markedly attenuated in C3H/HeJ mice with defective TLR4 signaling relative to control C3H/HeN mice. Notably, Mincle mRNA was expressed in bone-marrow cell (BMC)-derived proinflammatory M1 macrophages rather than in BMC-derived anti-inflammatory M2 macrophages in vitro. CONCLUSIONS--Our data suggest that Mincle is induced in adipose tissue macrophages in obesity at least partly through the saturated fatty acid/TLR4/NF-KB pathway, thereby suggesting its pathophysiologic role in obesity-induced adipose tissue inflammation. [ABSTRACT FROM AUTHOR]

Background Dipeptidyl peptidase-4 (DPP-4) inhibitors have various cellular effects that are associated with vascular protection. Here, we examined whether teneligliptin alters the pro-inflammatory phenotype of perivascular adipose tissue (PVAT) and inhibits atherogenesis. Methods and results Teneligliptin (60 mg/kg/day) was administered orally to apolipoprotein-E-deficient (ApoE −/− ) mice for 20 weeks. Teneligliptin significantly inhibited the development of atherosclerosis in the aortic arch compared with vehicle (P < 0.05), without alteration of blood glucose level or blood pressure. Histological analyses demonstrated that teneligliptin decreased lipid deposition and MCP-1 expression (P < 0.05, respectively), and tended to decrease macrophage accumulation in atherosclerotic plaques. The results of quantitative RT-PCR analysis demonstrated that teneligliptin reduced the expression of inflammatory molecules such as TNF-α and MCP-1 in the abdominal aorta. Furthermore, teneligliptin reduced the expression of a macrophage marker and Nox-4, a major NADPH oxidase subunit in adipocytes, in PVAT around the aortic arch. Administration of teneligliptin for 8 weeks ameliorated endothelium-dependent vasodilation and reduced oxidative stress as determined by urinary 8-OHdG excretion (P < 0.05) compared with vehicle. In vitro experiments demonstrated that exendin-4 (Ex-4), a GLP-1 analog, decreased the expression of inflammatory molecules in RAW264.7 cells. Also, Ex-4 decreased Nox4 expression in 3T3-L1 adipocytes. Conclusion Teneligliptin inhibited atherogenesis with attenuation of the inflammatory phenotype in PVAT. A GLP-1 analog suppressed pro-inflammatory activation of macrophages and adipocytes. Suppression of the pro-inflammatory phenotype of PVAT might contribute, at least partially, to the cardioprotective effects of teneligliptin. [ABSTRACT FROM AUTHOR]

Abstract: Much attention is currently focused on the role of perivascular adipose tissue in development of cardiovascular disease (CVD). Some researchers view it as promoting CVD through secretion of cytokines and growth factors called adipokines, while recent reports reveal that perivascular adipose tissue can exert a protective effect on CVD development. Furthermore, adiponectin, an anti-inflammatory adipokine, reportedly suppresses neointimal hyperplasia after endovascular injury, whereas such vascular remodeling is enhanced by pro-inflammatory adipokines secreted by perivascular adipose, such as tumor necrosis factor-α (TNF-α). These findings suggest that extent of vascular remodeling, a pathological process associated with CVD development, depends on the balance between pro- and anti-inflammatory adipokines secreted from perivascular adipose tissue. We previously demonstrated that angiopoietin-like protein 2 (Angptl2), a pro-inflammatory factor secreted by adipose tissue, promotes adipose tissue inflammation and subsequent systemic insulin resistance in obesity. Here, we examined whether Angptl2 secreted by perivascular adipose tissue contributes to vascular remodeling after endovascular injury in studies of transgenic mice expressing Angptl2 in adipose tissue (aP2-Angptl2 transgenic mice) and Angptl2 knockout mice (Angptl2 −/− mice). To assess the role of Angptl2 secreted by perivascular adipose tissue on vascular remodeling after endovascular injury, we performed adipose tissue transplantation experiments using these mice. Wild-type mice with perivascular adipose tissue derived from aP2-Angptl2 mice exhibited accelerated neointimal hyperplasia after endovascular injury compared to wild-type mice transplanted with wild-type tissue. Conversely, vascular inflammation and neointimal hyperplasia after endovascular injury were significantly attenuated in wild-type mice transplanted with Angptl2 −/− mouse-derived perivascular adipose tissue compared to wild-type mice transplanted with wild-type tissue. RT-PCR analysis revealed that mouse Angptl2 expression in perivascular adipose tissue was significantly increased by aging, hypercholesterolemia, and endovascular injury, all risk factors for coronary heart disease (CHD). Immunohistochemical and RT-PCR analysis of tissues from patients with CHD and from non-CHD patients indicated that ANGPTL2 expression in epicardial adipose tissue was unchanged. Interestingly, that analysis also revealed a positive correlation in ANGPTL2 and ADIPONECTIN expression in epicardial adipose tissue of non-CHD patients, a correlation not seen in CHD patients. However, in epicardial adipose tissue from CHD patients, ANGPTL2 expression was positively correlated with that of TNF-α, a correlation was not seen in non-CHD patients. These findings suggest that pro-inflammatory adipokines cooperatively accelerate CHD development and that maintaining a balance between pro- and anti-inflammatory adipokines likely protects non-CHD patients from developing CHD. Overall, our studies demonstrate that perivascular adipose tissue-secreted Angptl2 accelerates vascular inflammation and the subsequent CVD development. [Copyright &y& Elsevier]

Abstract: Telmisartan exerts anti-metabolic effects beyond its angiotensin receptor blockade activities, but the mechanisms have hitherto remained elusive. We sought to elucidate the peroxisome proliferator-activated receptor-γ (PPAR-γ)-dependent and PPAR-γ-independent mechanisms underlying the anti-metabolic effects of telmisartan in white adipose tissue. Nine-week-old male C57BL/6 mice were fed with a 60% high-fat diet for 6 weeks, with 1mg/kg telmisartan or vehicle administrated orally during the last 3 weeks. 3T3-L1 adipocytes were cultured with telmisartan either with 2-chloro-5-nitro-N-phenylbenzamide (GW9662), a selective irreversible antagonist of PPAR-γ, or compound C, an ATP-competitive inhibitor of AMPK. Western blotting and semiquantitative RT-PCR analysis were used to assess adiponectin, Sirt1, and AMPK levels. Lipid accumulation was assessed by Oil red O staining. The activation of transcription factor PPAR-γ2 was evaluated by using a luciferase reporter assay for mPPAR-γ2 expression plasmid vector. Treatment with telmisartan increased serum adiponectin levels in high-fat diet-fed mice concomitantly with an upregulation of adiponectin mRNA in visceral adipose tissue. In vitro telmisartan treatment dose-dependently increased adiponectin mRNA in 3T3-L1 cells; the increase was inhibited by compound C, but not by GW9662. Telmisartan increased expression of Sirt1 mRNA and Sirt1 protein as well as the phosphorylation of AMPK in 3T3-L1 cells. Telmisartan can increase adiponectin production in white adipose tissue partly via a PPAR-γ2-independent mechanism. Precise understanding of this molecular mechanism will require further investigation. [Copyright &y& Elsevier]