Vascular reactivity contributes to adipose tissue remodeling in obesity

2021 ◽  
Author(s):  
Hye-Jin Lee ◽  
Haifei Shi ◽  
Hella S. Brönneke ◽  
Bo-Yeong Jin ◽  
Sang-Hyun Choi ◽  
...  

Vascular reactivity of adipose tissue (AT) is hypothesized to play an important role in the development of obesity. However, the exact role of vascular reactivity in the development of obesity remains unclear. In this study, we investigated the chronological changes in vascular reactivity and the microenvironments of the visceral AT (VAT) and subcutaneous AT (SAT) in lean and obese mice. Changes in blood flow levels induced by a β-adrenoceptor agonist (isoproterenol) were significantly lower in the VAT of the mice fed a high-fat diet (HFD) for 1 and 12 weeks, compared to those in the VAT of the mice fed a low-fat diet (LFD) for the same period; no significant change was observed in the SAT of any mouse group, suggesting depot-specific vascular reactivity of AT. Consistently, the hypoxic area and the expression of genes associated with angiogenesis and macrophage recruitment were increased in the VAT (but not in the SAT) of mice fed an HFD for 1 week, compared with mice fed an LFD. These changes occurred with no morphological changes, including those related to adipocyte size, AT vessel density, and the diameter and pericyte coverage of the endothelium, suggesting a determinant role of vascular reactivity in the type of AT remodeling. The suppression of vascular reactivity was accompanied by increased endothelin-1 gene expression and extracellular matrix (ECM) stiffness only in the VAT, implying enhanced contractile activities of the vasculature and ECM. The results suggest a depot-specific role of vascular reactivity in AT remodeling during the development of obesity.

Endocrinology ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 3525-3538 ◽  
Author(s):  
Hong Guo ◽  
Merlijn Bazuine ◽  
Daozhong Jin ◽  
Merry M. Huang ◽  
Samuel W. Cushman ◽  
...  

Lipocalin 2 (Lcn2) has previously been characterized as an adipokine/cytokine playing a role in glucose and lipid homeostasis. In this study, we investigate the role of Lcn2 in adipose tissue remodeling during high-fat diet (HFD)-induced obesity. We find that Lcn2 protein is highly abundant selectively in inguinal adipose tissue. During 16 weeks of HFD feeding, the inguinal fat depot expanded continuously, whereas the expansion of the epididymal fat depot was reduced in both wild-type (WT) and Lcn2−/− mice. Interestingly, the depot-specific effect of HFD on fat mass was exacerbated and appeared more pronounced and faster in Lcn2−/− mice than in WT mice. In Lcn2−/− mice, adipocyte hypertrophy in both inguinal and epididymal adipose tissue was more profoundly induced by age and HFD when compared with WT mice. The expression of peroxisome proliferator-activated receptor-γ protein was significantly down-regulated, whereas the gene expression of extracellular matrix proteins was up-regulated selectively in epididymal adipocytes of Lcn2−/− mice. Consistent with these observations, collagen deposition was selectively higher in the epididymal, but not in the inguinal adipose depot of Lcn2−/− mice. Administration of the peroxisome proliferator-activated receptor-γ agonist rosiglitazone (Rosi) restored adipogenic gene expression. However, Lcn2 deficiency did not alter the responsiveness of adipose tissue to Rosi effects on the extracellular matrix expression. Rosi treatment led to the further enlargement of adipocytes with improved metabolic activity in Lcn2−/− mice, which may be associated with a more pronounced effect of Rosi treatment in reducing TGF-β in Lcn2−/− adipose tissue. Consistent with these in vivo observations, Lcn2 deficiency reduces the adipocyte differentiation capacity of stromal-vascular cells isolated from HFD-fed mice in these cells. Herein Rosi treatment was again able to stimulate adipocyte differentiation to a similar extent in WT and Lcn2−/− inguinal and epididymal stromal-vascular cells. Thus, combined, our data indicate that Lcn2 has a depot-specific role in HFD-induced adipose tissue remodeling.


Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2427
Author(s):  
Emily C. Graff ◽  
Han Fang ◽  
Desiree Wanders ◽  
Robert L. Judd

Obesity is an immunometabolic disease associated with chronic inflammation and the dysregulation of pro- and anti-inflammatory cytokines. One hallmark of obesity is reduced concentrations of the anti-inflammatory adipokine, adiponectin. Pharmacologic doses of niacin produce multiple metabolic benefits, including attenuating high-fat diet (HFD)-induced adipose tissue inflammation and increasing adiponectin concentrations. To determine if adiponectin mediates the anti-inflammatory effects of niacin, male C57BL/6J (WT) and adiponectin null (Adipoq-/-) mice were maintained on a low-fat diet (LFD) or HFD for 6 weeks, before being administered either vehicle or niacin (360 mg/kg/day) for 5 weeks. HFD-fed mice had increased expression of genes associated with macrophage recruitment (Ccl2) and number (Cd68), and increased crown-like structure (CLS) number in adipose tissue. While niacin attenuated Ccl2 expression, there were no effects on Cd68 or CLS number. The absence of adiponectin did not hinder the ability of niacin to reduce Ccl2 expression. HFD feeding increased gene expression of inflammatory markers in the adipose tissue of WT and Adipoq-/- mice. While niacin tended to decrease the expression of inflammatory markers in WT mice, niacin increased their expression in HFD-fed Adipoq-/- mice. Therefore, our results indicate that the absence of adiponectin alters the effects of niacin on markers of adipose tissue inflammation in HFD-fed mice, suggesting that the effects of niacin on tissue cytokines may involve adiponectin.


2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Yusaku Mori ◽  
Michishige Terasaki ◽  
Munenori Hiromura ◽  
Tomomi Saito ◽  
Hideki Kushima ◽  
...  

Abstract Background Excess fat deposition could induce phenotypic changes of perivascular adipose tissue (PVAT remodeling), which may promote the progression of atherosclerosis via modulation of adipocytokine secretion. However, it remains unclear whether and how suppression of PVAT remodeling could attenuate vascular injury. In this study, we examined the effect of sodium-glucose cotransporter 2 (SGLT2) inhibitor, luseogliflozin on PVAT remodeling and neointima formation after wire injury in mice. Methods Wilt-type mice fed with low-fat diet (LFD) or high-fat diet (HFD) received oral administration of luseogliflozin (18 mg/kg/day) or vehicle. Mice underwent bilateral femoral artery wire injury followed by unilateral removal of surrounding PVAT. After 25 days, injured femoral arteries and surrounding PVAT were analyzed. Results In LFD-fed lean mice, neither luseogliflozin treatment or PVAT removal attenuated the intima-to-media (I/M) ratio of injured arteries. However, in HFD-fed mice, luseogliflozin or PVAT removal reduced the I/M ratio, whereas their combination showed no additive reduction. In PVAT surrounding injured femoral arteries of HFD-fed mice, luseogliflozin treatment decreased the adipocyte sizes. Furthermore, luseogliflozin reduced accumulation of macrophages expressing platelet-derived growth factor-B (PDGF-B) and increased adiponectin gene expression. Gene expression levels of Pdgf-b in PVAT were correlated with the I/M ratio. Conclusions Our present study suggests that luseogliflozin could attenuate neointimal hyperplasia after wire injury in HFD-fed mice partly via suppression of macrophage PDGF-B expression in PVAT. Inhibition of PVAT remodeling by luseogliflozin may be a novel therapeutic target for vascular remodeling after angioplasty.


2011 ◽  
Vol 8 (1) ◽  
pp. 5 ◽  
Author(s):  
Venkata J Adapala ◽  
Kimberly K Buhman ◽  
Kolapo M Ajuwon

1998 ◽  
Vol 274 (3) ◽  
pp. E493-E501 ◽  
Author(s):  
F. Bradley Hillgartner ◽  
Tina Charron

Transcription of fatty acid synthase (FAS) and malic enzyme (ME) in avian liver is low during starvation or feeding a low-carbohydrate, high-fat diet and high during feeding a high-carbohydrate, low-fat diet. The role of glucose in the nutritional control of FAS and ME was investigated by determining the effects of this metabolic fuel on expression of FAS and ME in primary cultures of chick embryo hepatocytes. In the presence of triiodothyronine, glucose (25 mM) stimulated an increase in the activity and mRNA abundance of FAS and ME. These effects required the phosphorylation of glucose to glucose 6-phosphate but not further metabolism downstream of the aldolase step of the glycolytic pathway. Xylitol mimicked the effects of glucose on FAS and ME expression, suggesting that an intermediate of the pentose phosphate pathway may be involved in mediating this response. The effects of glucose on the mRNA abundance of FAS and ME were accompanied by similar changes in transcription of FAS and ME. These data support the hypothesis that glucose plays a role in mediating the effects of nutritional manipulation on transcription of FAS and ME in liver.


2008 ◽  
Vol 295 (2) ◽  
pp. E313-E322 ◽  
Author(s):  
Can Pang ◽  
Zhanguo Gao ◽  
Jun Yin ◽  
Jin Zhang ◽  
Weiping Jia ◽  
...  

The biological role of macrophage infiltration into adipose tissue in obesity remains to be fully understood. We hypothesize that macrophages may act to stimulate angiogenesis in the adipose tissue. This possibility was examined by determining macrophage expression of angiogenic factor PDGF (platelet-derived growth factor) and regulation of tube formation of endothelial cells by PDGF. The data suggest that endothelial cell density was reduced in the adipose tissue of ob/ob mice. Expression of endothelial marker CD31 was decreased in protein and mRNA. The reduction was associated with an increase in macrophage infiltration. In the obese mice, PDGF concentration was elevated in the plasma, and its mRNA expression was increased in adipose tissue. Macrophages were found to be a major source of PDGF in adipose tissue, as deletion of macrophages led to a significant reduction in PDGF mRNA. In cell culture, PDGF expression was induced by hypoxia, and tube formation of endothelial cells was induced by PDGF. The PDGF activity was dependent on S6K, as inhibition of S6K in endothelial cells led to inhibition of the PDGF activity. We conclude that, in response to the reduced vascular density, macrophages may express PDGF in adipose tissue to facilitate capillary formation in obesity. Although the PDGF level is elevated in adipose tissue, its activity in angiogenesis is dependent on the availability of sufficient endothelial cells. The study suggests a new function of macrophages in the adipose tissue in obesity.


2008 ◽  
Vol 295 (2) ◽  
pp. E331-E338 ◽  
Author(s):  
Neel S. Singhal ◽  
Rajesh T. Patel ◽  
Yong Qi ◽  
Yun-Sik Lee ◽  
Rexford S. Ahima

Resistin has been linked to components of the metabolic syndrome, including obesity, insulin resistance, and hyperlipidemia. We hypothesized that resistin deficiency would reverse hyperlipidemia in genetic obesity. C57Bl/6J mice lacking resistin [resistin knockout (RKO)] had similar body weight and fat as wild-type mice when fed standard rodent chow or a high-fat diet. Nonetheless, hepatic steatosis, serum cholesterol, and very low-density lipoprotein (VLDL) secretion were decreased in diet-induced obese RKO mice. Resistin deficiency exacerbated obesity in ob/ob mice, but hepatic steatosis was drastically attenuated. Moreover, the levels of triglycerides, cholesterol, insulin, and glucose were reduced in ob/ob-RKO mice. The antisteatotic effect of resistin deficiency was related to reductions in the expression of genes involved in hepatic lipogenesis and VLDL export. Together, these results demonstrate a crucial role of resistin in promoting hepatic steatosis and hyperlipidemia in obese mice.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Huiying Cong ◽  
Wenxia Zhong ◽  
Yiying Wang ◽  
Shoichiro Ikuyama ◽  
Bin Fan ◽  
...  

Beige adipocytes in white adipose tissue (WAT) have received considerable recognition because of their potential protective effect against obesity. Pycnogenol (PYC), extracted from French maritime pine bark, has anti-inflammatory and antioxidant properties and can improve lipid profiles. However, the effect of PYC on obesity has never been explored. In this study, we investigated the effects of PYC on obesity and WAT browning in apolipoprotein E- (ApoE-) deficient mice. The results showed that PYC treatment clearly reversed body weight and the mass of eWAT gain resulting from a high-cholesterol and high-fat diet (HCD), but no difference in food intake. The morphology results showed that the size of the adipocytes in the PYC-treated mice was obviously smaller than that in the HCD-fed mice. Next, we found that PYC upregulated the expression of genes related to lipolysis (ATGL and HSL), while it decreased the mRNA level of PLIN1. PYC significantly increased the expression of UCP1 and other genes related to beige adipogenesis. Additionally, PYC increased the expression of proteins related to the protein kinase A (PKA) signaling pathway. The findings suggested that PYC decreased obesity by promoting lipolysis and WAT browning. Thus, PYC may be a novel therapeutic target for obesity.


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