OBJECTIVETo characterize the phenotypic changes of adipose tissue macrophages (ATMs) under different conditions of insulin sensitivity.RESEARCH DESIGN AND METHODSThe number and the expressions of marker genes for M1 and M2 macrophages from mouse epididymal fat tissue were analyzed using flow cytometry after the mice had been subjected to a high-fat diet (HFD) and pioglitazone treatment.RESULTSMost of the CD11c-positive M1 macrophages and the CD206-positive M2 macrophages in the epididymal fat tissue were clearly separated using flow cytometry. The M1 and M2 macrophages exhibited completely different gene expression patterns. Not only the numbers of M1 ATMs and the expression of M1 marker genes, such as tumor necrosis factor-α and monocyte chemoattractant protein-1, but also the M1-to-M2 ratio were increased by an HFD and decreased by subsequent pioglitazone treatment, suggesting the correlation with whole-body insulin sensitivity. We also found that the increased number of M2 ATMs after an HFD was associated with the upregulated expression of interleukin (IL)-10, an anti-inflammatory Th2 cytokine, in the adipocyte fraction as well as in adipose tissue. The systemic overexpression of IL-10 by an adenovirus vector increased the expression of M2 markers in adipose tissue.CONCLUSIONSM1 and M2 ATMs constitute different subsets of macrophages. Insulin resistance is associated with both the number of M1 macrophages and the M1-to-M2 ratio. The increased expression of IL-10 after an HFD might be involved in the increased recruitment of M2 macrophages.

Nonalcoholic fatty liver disease (NAFLD) is an abnormal liver metabolism often observed with insulin resistance and metabolic syndrome. Calorie restriction is a useful treatment for NAFLD and reportedly prolongs the life spans of several species in which sirtuin plays an important role. In this study, we examined whether the activation of SIRT1, a mammalian ortholog of sirtuin, may ameliorate the development of NAFLD. Monosodium glutamate (MSG) mice, which exhibited obesity and insulin resistance, were treated with SRT1720, a specific SIRT1 activator from the age of 6-16 wk. Sixteen-week-old MSG mice exhibited increased liver triglyceride content and elevated levels of aminotransferase. SRT1720 treatment significantly reduced these levels without affecting body weight or food intake. These results suggested that the administration of SRT1720 ameliorated the development of NAFLD in MSG mice. The expressions of lipogenic genes, such as sterol regulatory element-binding protein-1c, acetyl-CoA carboxylase, and fatty acid synthase, and the serum lipid profiles, including free fatty acids, were elevated in MSG mice and were reduced by SRT1720 treatment. SRT1720 treatment also reduced the expressions of lipogenic genes in cultured HepG2 cells. Furthermore, SRT1720 treatment decreased the expressions of marker genes for oxidative stress and inflammatory cytokines in the liver of MSG mice. Taken together, SRT1720 treatment may reduce liver lipid accumulation, at least in part, by directly reducing the expressions of lipogenic genes. The reduction of oxidative stress and inflammation may also be involved in the amelioration of NAFLD.

Diet-induced obesity is reported to induce a phenotypic switch in adipose tissue macrophages from an antiinflammatory M2 state to a proinflammatory M1 state. Telmisartan, an angiotensin II type 1 receptor blocker and a peroxisome proliferator-activated receptor-γ agonist, reportedly has more beneficial effects on insulin sensitivity than other angiotensin II type 1 receptor blockers. In this study, we studied the effects of telmisartan on the adipose tissue macrophage phenotype in high-fat-fed mice. Telmisartan was administered for 5 wk to high-fat-fed C57BL/6 mice. Insulin sensitivity, macrophage infiltration, and the gene expressions of M1 and M2 markers in visceral adipose tissues were then examined. An insulin- or a glucose-tolerance test showed that telmisartan treatment improved insulin resistance, decreasing the body weight gain, visceral fat weight, and adipocyte size without affecting the amount of energy intake. Telmisartan reduced the mRNA expression of CD11c and TNF-α, M1 macrophage markers, and significantly increased the expressions of M2 markers, such as CD163, CD209, and macrophage galactose N-acetyl-galactosamine specific lectin (Mgl2), in a quantitative RT-PCR analysis. A flow cytometry analysis showed that telmisartan decreased the number of M1 macrophages in visceral adipose tissues. In conclusion, telmisartan improves insulin sensitivity and modulates adipose tissue macrophage polarization to an antiinflammatory M2 state in high-fat-fed mice.

Background The high mortality rate in Coronavirus Disease (COVID-19) patients is associated with their comorbid conditions. Therefore, it is important to identify risk factors associated with poor outcomes among COVID-19 patients. The aims of this study were to find out the comorbidities in case of death due to COVID-19. Methods The design of this study was a retrospective descriptive method with a confirmed COVID-19 patient on hospitalized at Dr. Wahidin Sudirohusodo Hospital from March to September 2020. Ethics Council recommendation number: 357/UN4.6.4.5.31/PP36/2020. Results A total of 454 patients were included of this study. 78 (17.18%) patients death due to COVID-19, consisting of 52 (66.67%) male and 26 (33.33%) female. Range of ages between 18 and 85 years. The highest mortality rate occurred in the age group ≥60 years (35; 51.47%), followed by the age group of 45–59 years (33; 48.53%), and the age group of <45 years (10; 12%). The prevalent comorbidity was hypertension (42.31%), cardiovascular disease (30.77%), diabetes (28.21%), chronic kidney disease (23.08%), malignancy (15.38%), obesity (15.38%), chronic liver disease (7.69%), chronic respiratory disease (6.41%), immune related disease (3.85%), and non-traumatic cerebral infarction (3.85%). 41 (52.56%) patients reported having two or more comorbidities, and 37 (47.44%) only has one comorbidity. Elevated neutrophil-to-lymphocyte ratio (NLR) ≥3.13 was seen in the majority of patients (68; 87.18%). The mean value of NLR was 20.94. Conclusions Hypertension, cardiovascular disease, and diabetes were the most common comorbidity in patients death due to COVID-19. More than half of the patients had two or more comorbidities.

Proinflammatory cytokines are recently reported to inhibit insulin signaling causing insulin resistance. IL-1alpha is also one of the proinflammatory cytokines; however, it has not been clarified whether IL-1alpha may also cause insulin resistance. Here, we investigated the effects of IL-1alpha treatment on insulin signaling in 3T3-L1 adipocytes. IL-1alpha treatment up to 4 h did not alter insulin-stimulated insulin receptor tyrosine phosphorylation, whereas tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and the association with phosphatidylinositol 3-kinase were partially inhibited with the maximal inhibition in around 15 min. IRS-1 was transiently phosphorylated on some serine residues around 15 min after IL-1alpha stimulation, when several serine kinases, IkappaB kinase, c-Jun-N-terminal kinase, ERK, and p70S6K were activated. Chemical inhibitors for these kinases inhibited IL-1alpha-induced serine phosphorylation of IRS-1. Tyrosine phosphorylation of IRS-1 was recovered only by the IKK inhibitor or JNK inhibitor, suggesting specific involvement of these two kinases. Insulin-stimulated Akt phosphorylation and 2-deoxyglucose uptake were not inhibited only by IL-1alpha. Interestingly, Akt phosphorylation was synergistically inhibited by IL-1alpha in the presence of IL-6. Taken together, short-term IL-1alpha treatment transiently causes insulin resistance at IRS-1 level with its serine phosphorylation. IL-1alpha may suppress insulin signaling downstream of IRS-1 in the presence of other cytokines, such as IL-6.