Adipose tissue hypoxia and low-grade inflammation: a possible mechanism for ethanol-related glucose intolerance?

2015 ◽  
Vol 113 (9) ◽  
pp. 1355-1364 ◽  
Author(s):  
Zhen He ◽  
Min Li ◽  
Dongmei Zheng ◽  
Qing Chen ◽  
Wenwen Liu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Glucose Tolerance ◽  
Hypoxia Inducible Factor ◽  
Ethanol Consumption ◽  
Oral Glucose ◽  
Low Grade ◽  
Tnf Α ◽  
Low Grade Inflammation

The exact mechanism of ethanol's effects on glucose tolerance has not been well determined. The present study focuses for the first time on hypoxia and low-grade inflammation in adipose tissue (AT). In the in vivo experiments, twenty-four male Wistar rats were randomly allocated into control and ethanol feeding groups. Ethanol-treated rats received edible ethanol once a day at a total dosage of 5 g/kg per d, and the controls received distilled water. Ethanol volumes were adjusted every week. At the end of 8 weeks, we carried out an oral glucose tolerance test. Blood and AT were collected for measuring hypoxia-inducible factor-1α (HIF-1α), GLUT1, TNF-α, IL-6, leptin and vascular endothelial growth factor (VEGF). In the in vitro experiments, differentiated OP9 adipocytes were incubated with 100 mm of ethanol for 48 h; the media and cells were then collected for measuring HIF-1α, GLUT1, TNF-α and IL-6. The results showed that long-term ethanol consumption impaired glucose tolerance in rats. Ethanol consumption had little influence on body weight, but both epididymal and perirenal AT were markedly enlarged in the ethanol-treated rats as compared to the controls. Visceral adipose tissue (VAT) had accumulated, and the protein levels of HIF-1α and GLUT1, the indicators of hypoxia in rat epididymal AT and OP9 adipocytes, were elevated. Secondary to the AT hypoxia, the levels of inflammation-related adipokines, such as TNF-α, IL-6, leptin and VEGF, were increased. Based on these findings, we conclude that VAT hypoxia and low-grade inflammation might be a new mechanism in the treatment of ethanol-related diabetes.

scholarly journals 4-Hydroxyisoleucine: experimental evidence of its insulinotropic and antidiabetic properties

1999 ◽  
Vol 277 (4) ◽  
pp. E617-E623 ◽  
Author(s):  
Christophe Broca ◽  
René Gross ◽  
Pierre Petit ◽  
Yves Sauvaire ◽  
Michèle Manteghetti ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Insulin Response ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Insulin Dependent ◽  
Glucose Tolerance Tests ◽  
Insulin Dependent Diabetic ◽  
Single Intravenous Administration

We have recently shown in vitro that 4-hydroxyisoleucine (4-OH-Ile), an amino acid extracted from fenugreek seeds, potentiates insulin secretion in a glucose-dependent manner. The present study was designed to investigate whether 4-OH-Ile could exert in vivo insulinotropic and antidiabetic properties. For this purpose, intravenous or oral glucose tolerance tests (IVGTTs and OGTTs, respectively) were performed not only in normal animals but also in a type II diabetes rat model. During IVGTT in normal rats or OGTT in normal dogs, 4-OH-Ile (18 mg/kg) improved glucose tolerance. The lactonic form of 4-OH-Ile was ineffective in normal rats. In non-insulin-dependent diabetic (NIDD) rats, a single intravenous administration of 4-OH-Ile (50 mg/kg) partially restored glucose-induced insulin response without affecting glucose tolerance; a 6-day subchronic administration of 4-OH-Ile (50 mg/kg, daily) reduced basal hyperglycemia, decreased basal insulinemia, and slightly, but significantly, improved glucose tolerance. In vitro, 4-OH-Ile (200 μM) potentiated glucose (16.7 mM)-induced insulin release from NIDD rat-isolated islets. So, the antidiabetic effects of 4-OH-Ile on NIDD rats result, at least in part, from a direct pancreatic B cell stimulation.

scholarly journals Puerarin Attenuates Obesity-Induced Inflammation and Dyslipidemia by Regulating Macrophages and TNF-Alpha in Obese Mice

Biomedicines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 175
Author(s):  
Ji-Won Noh ◽  
Hee-Kwon Yang ◽  
Min-Soo Jun ◽  
Byung-Cheol Lee
Keyword(s):  
Adipose Tissue ◽  
In Silico ◽  
Tolerance Test ◽  
Low Grade ◽  
Adipocyte Size ◽  
Metabolic Complications ◽  
Immunological Mechanisms ◽  
Tnf Α ◽  
Test Serum

Obesity causes low-grade inflammation that results in dyslipidemia and insulin resistance. We evaluated the effect of puerarin on obesity and metabolic complications both in silico and in vivo and investigated the underlying immunological mechanisms. Twenty C57BL/6 mice were divided into four groups: normal chow, control (HFD), HFD + puerarin (PUE) 200 mg/kg, and HFD + atorvastatin (ATO) 10 mg/kg groups. We examined bodyweight, oral glucose tolerance test, serum insulin, oral fat tolerance test, serum lipids, and adipocyte size. We also analyzed the percentage of total, M1, and M2 adipose tissue macrophages (ATMs) and the expression of F4/80, tumor necrosis factor-α (TNF-α), C-C motif chemokine ligand 2 (CCL2), CCL4, CCL5, and C-X-C motif chemokine receptor 4. In silico, we identified the treatment-targeted genes of puerarin and simulated molecular docking with puerarin and TNF, M1, and M2 macrophages based on functionally enriched pathways. Puerarin did not significantly change bodyweight but significantly improved fat pad weight, adipocyte size, fat area in the liver, free fatty acids, triglycerides, total cholesterol, and HDL-cholesterol in vivo. In addition, puerarin significantly decreased the ATM population and TNF-α expression. Therefore, puerarin is a potential anti-obesity treatment based on its anti-inflammatory effects in adipose tissue.

scholarly journals Multinucleated giant cells in adipose tissue are specialized in adipocyte degradation

2020 ◽  
Author(s):  
Ada Admin ◽  
Julia Braune ◽  
Andreas Lindhorst ◽  
Janine Fröba ◽  
Constance Hobusch ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
High Fat Diet ◽  
Ex Vivo ◽  
Giant Cells ◽  
Low Grade ◽  
Adipose Tissue Macrophages ◽  
Visceral Adipose ◽  
Low Grade Inflammation

Obesity is associated with a chronic low-grade inflammation in visceral adipose tissue (AT) characterized by an increasing number of adipose tissue macrophages (ATMs) and linked to type 2 diabetes. AT inflammation is histologically indicated by the formation of so-called crown-like structures (CLS), as accumulation of ATMs around dying adipocytes, and the occurrence of multi-nucleated giant cells (MGCs). However to date, the function of MGCs in obesity is unknown. Hence, the aim of this study was to characterize MGCs in AT and unravel the function of these cells. <p>We demonstrate that MGCs occur in obese patients and after 24 weeks of high fat diet (HFD) in mice, accompanying signs of AT inflammation and then represent ~3% of ATMs in mice. Mechanistically, we found evidence that adipocyte death triggers MGC formation. Most importantly, MGCs in obese AT have a higher capacity to phagocytose oversized particles, such as adipocytes, as shown by live-imaging of AT, 45 µm bead uptake <i>ex vivo</i> and a higher lipid content <i>in vivo</i>. Finally, we show that IL-4 treatment is sufficient to increase the number of MGCs in AT, whereas other factors maybe more important for endogenous MGC formation <i>in vivo</i>.</p>

scholarly journals HIF-1α contributes to Ang II-induced inflammatory cytokine production in podocytes

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Hao Huang ◽  
Yanqin Fan ◽  
Zhao Gao ◽  
Wei Wang ◽  
Ning Shao ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Renin Angiotensin System ◽  
Inflammatory Factors ◽  
Ang Ii ◽  
Angiotensin System ◽  
Inflammatory Injury ◽  
Tnf Α

Abstract Background Studies have indicated that changed expression of hypoxia-inducible factor-1α (HIF-1α) in epithelial cells from the kidney could affect the renal function in chronic kidney disease (CKD). As Angiotensin II (Ang II) is a critical active effector in the renin-angiotensin system (RAS) and was proved to be closely related to the inflammatory injury. Meanwhile, researchers found that Ang II could alter the expression of HIF-1α in the kidney. However, whether HIF-1α is involved in mediating Ang II-induced inflammatory injury in podocytes is not clear. Methods Ang II perfusion animal model were established to assess the potential role of HIF-1α in renal injury in vivo. Ang II stimulated podocytes to observe the corresponding between HIF-1α and inflammatory factors in vitro. Results The expression of inflammatory cytokines such as MCP-1 and TNF-α was increased in the glomeruli from rats treated with Ang II infusion compared with control rats. Increased HIF-1α expression in the glomeruli was also observed in Ang II-infused rats. In vitro, Ang II upregulated the expression of HIF-1α in podocytes. Furthermore, knockdown of HIF-1α by siRNA decreased the expression of MCP-1 and TNF-α. Moreover, HIF-1α siRNA significantly diminished the Ang II-induced overexpression of HIF-1α. Conclusion Collectively, our results suggest that HIF-1α participates in the inflammatory response process caused by Ang II and that downregulation of HIF-1α may be able to partially protect or reverse inflammatory injury in podocytes.

Betaine reduces the expression of inflammatory adipokines caused by hypoxia in human adipocytes

2012 ◽  
Vol 109 (1) ◽  
pp. 43-49 ◽  
Author(s):  
K. Olli ◽  
S. Lahtinen ◽  
N. Rautonen ◽  
K. Tiihonen
Keyword(s):  
Adipose Tissue ◽  
Inflammatory Markers ◽  
Mrna Level ◽  
Low Grade ◽  
Human Adipocytes ◽  
Low Oxygen ◽  
Hypoxic Conditions ◽  
Tnf Α ◽  
Oxygen Conditions ◽  
Low Grade Inflammation

Obesity is characterised by a state of chronic low-grade inflammation and the elevated circulating and tissue levels of inflammatory markers, including inflammation-related adipokines, released from white adipose tissue. The expression and release of these adipokines generally rises as the adipose tissue expands and hypoxic conditions start to develop within the tissue. Here, the effect of betaine, a trimethylglycine having a biological role as an osmolyte and a methyl donor, on the expression of inflammation-related markers was tested in human adipocytes under hypoxia. Differentiated adipocytes were cultivated under low (1 %) oxygen tension for 8–20 h. The expression of different adipokines, including IL-6, leptin, PPARγ, TNF-α and adiponectin, was measured by quantitative PCR by determining the relative mRNA level from the adipocytes. Hypoxia, in general, led to a decrease in the expression of PPARγ mRNA in human adipocytes, whereas the expression levels of leptin and IL-6 mRNA were substantially increased by hypoxia. The cultivation of adipocytes under hypoxia also led to a reduction in the expression of TNF-α mRNA. The results showed that hypoxia increased the relative quantification of leptin gene transcription, and that betaine (250 μmol/l) reduced this effect, caused by low oxygen conditions. Under hypoxia, betaine also reduced the mRNA level of the pro-inflammatory markers IL-6 and TNF-α. These results demonstrate that the extensive changes in the expression of inflammation-related adipokines in human adipocytes caused by hypoxia can be diminished by the presence of physiologically relevant concentrations of betaine.

Adipose-on-a-chip: a dynamic microphysiological in vitro model of the human adipose for immune-metabolic analysis in type II diabetes

Lab on a Chip ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 241-253 ◽  
Author(s):  
Yunxiao Liu ◽  
Patthara Kongsuphol ◽  
Su Yin Chiam ◽  
Qing Xin Zhang ◽  
Sajay Bhuvanendran Nair Gourikutty ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Immune Cells ◽  
Type Ii Diabetes ◽  
In Vitro Model ◽  
Low Grade ◽  
Type Ii ◽  
Metabolic Analysis ◽  
Vitro Model ◽  
Low Grade Inflammation

Infiltration of immune cells into adipose tissue is associated with chronic low-grade inflammation in obese individuals.

The Relation Between Glucose Tolerance and Insulin Binding to Circulating Monocytes in Obese Children

PEDIATRICS ◽  
1982 ◽  
Vol 70 (4) ◽  
pp. 633-637
Author(s):  
Kaichi Kida ◽  
Noriyoshi Watanabe ◽  
Yoshiki Fujisawa ◽  
Yoshinori Goto ◽  
Hiroshi Matsuda
Keyword(s):  
Glucose Tolerance ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Tolerance Test ◽  
Quantitative Relation ◽  
Immunoreactive Insulin ◽  
Oral Glucose ◽  
Obese Children

The quantitative relation between insulin binding to circulating monocytes in vitro and glucose tolerance in obese children in vivo is reported. Sixty-one obese children and 11 healthy control children participated in this study. The oral glucose tolerance test (OGTT) was performed by giving them glucose (1.75 gm/kg of body weight), orally in the morning, and the binding of 125I-labeled insulin to circulating monocytes in vitro was measured prior to OGTT. The glucose tolerance expressed by ΣBS (milligrams/100 ml), the sum of the plasma glucose (blood sugar [BS]) values at OGTT, was significantly correlated with the degree of overweight (r = .316, P &lt; .01) and more highly with ΣIRI (microunits per milliliter), the sum of immunoreactive insulin (IRI) values at OGTT (r = .512, P &lt; .001). Insulin binding to monocytes in vitro (picograms/106 cells) was inversely correlated with the degree of overweight (r = -. 687, P &lt; .001). Furthermore, ΣBS was inversely correlated significantly with insulin binding to monocytes in vitro (r = -.435, P &lt; .002). These data suggest that the decrease of insulin receptors might be one cause for the impairment of the glucose tolerance associated with obesity in children.

Regulation of adiponectin by adipose tissue-derived cytokines: in vivo and in vitro investigations in humans

2003 ◽  
Vol 285 (3) ◽  
pp. E527-E533 ◽  
Author(s):  
Jens M. Bruun ◽  
Aina S. Lihn ◽  
Camilla Verdich ◽  
Steen B. Pedersen ◽  
Søren Toubro ◽  
...  
Keyword(s):  
Weight Loss ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Mrna Levels ◽  
Plasma Adiponectin ◽  
Tnf Α ◽  
Adiponectin Mrna ◽  
Before And After

Adiponectin is an adipose tissue-specific protein that is abundantly present in the circulation and suggested to be involved in insulin sensitivity and development of atherosclerosis. Because cytokines are suggested to regulate adiponectin, the aim of the present study was to investigate the interaction between adiponectin and three adipose tissue-derived cytokines (IL-6, IL-8, and TNF-α). The study was divided into three substudies as follows: 1) plasma adiponectin and mRNA levels in adipose tissue biopsies from obese subjects [mean body mass index (BMI): 39.7 kg/m2, n = 6] before and after weight loss; 2) plasma adiponectin in obese men (mean BMI: 38.7 kg/m2, n = 19) compared with lean men (mean BMI: 23.4 kg/m2, n = 10) before and after weight loss; and 3) in vitro direct effects of IL-6, IL-8, and TNF-α on adiponectin mRNA levels in adipose tissue cultures. The results were that 1) weight loss resulted in a 51% ( P < 0.05) increase in plasma adiponectin and a 45% ( P < 0.05) increase in adipose tissue mRNA levels; 2) plasma adiponectin was 53% ( P < 0.01) higher in lean compared with obese men, and plasma adiponectin was inversely correlated with adiposity, insulin sensitivity, and IL-6; and 3) TNF-α ( P < 0.01) and IL-6 plus its soluble receptor ( P < 0.05) decreased adiponectin mRNA levels in vitro. The inverse relationship between plasma adiponectin and cytokines in vivo and the cytokine-induced reduction in adiponectin mRNA in vitro suggests that endogenous cytokines may inhibit adiponectin. This could be of importance for the association between cytokines (e.g., IL-6) and insulin resistance and atherosclerosis.

scholarly journals TNF-α Represses β-Klotho Expression and Impairs FGF21 Action in Adipose Cells: Involvement of JNK1 in the FGF21 Pathway

Endocrinology ◽  
2012 ◽  
Vol 153 (9) ◽  
pp. 4238-4245 ◽  
Author(s):  
Julieta Díaz-Delfín ◽  
Elayne Hondares ◽  
Roser Iglesias ◽  
Marta Giralt ◽  
Carme Caelles ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
High Fat Diet ◽  
Mouse Embryonic Fibroblast ◽  
Fibroblast Growth Factor 21 ◽  
High Fat ◽  
Fgf Receptor ◽  
Inflammatory Status ◽  
Tnf Α

Fibroblast growth factor 21 (FGF21) is a member of the FGF family that reduces glycemia and ameliorates insulin resistance. Adipose tissue is a main target of FGF21 action. Obesity is associated with a chronic proinflammatory state. Here, we analyzed the role of proinflammatory signals in the FGF21 pathway in adipocytes, evaluating the effects of TNF-α on β-Klotho and FGF receptor-1 expression and FGF21 action in adipocytes. We also determined the effects of rosiglitazone on β-Klotho and FGF receptor-1 expression in models of proinflammatory signal induction in vitro and in vivo (high-fat diet-induced obesity). Because c-Jun NH2-terminal kinase 1 (JNK1) serves as a sensing juncture for inflammatory status, we also evaluated the involvement of JNK1 in the FGF21 pathway. TNF-α repressed β-Klotho expression and impaired FGF21 action in adipocytes. Rosiglitazone prevented the reduction in β-Klotho expression elicited by TNF-α. Moreover, β-Klotho levels were reduced in adipose tissue from high-fat diet-induced obese mice, whereas rosiglitazone restored β-Klotho to near-normal levels. β-Klotho expression was increased in white fat from JNK1−/− mice. The absence of JNK1 increased the responsiveness of mouse embryonic fibroblast-derived adipocytes and brown adipocytes to FGF21. In conclusion, we show that proinflammatory signaling impairs β-Klotho expression and FGF21 responsiveness in adipocytes. We also show that JNK1 activity is involved in modulating FGF21 effects in adipocytes. The impairment in the FGF21 response machinery in adipocytes and the reduction in FGF21 action in response to proinflammatory signals may play important roles in metabolic alterations in obesity and other diseases associated with enhanced inflammation.

scholarly journals TRPV1 Antagonists as Novel Anti-Diabetic Agents: Regulation of Oral Glucose Tolerance and Insulin Secretion Through Reduction of Low-Grade Inflammation?

2019 ◽  
Vol 7 (8) ◽  
pp. 82 ◽  
Author(s):  
Dorte X. Gram ◽  
Josefine Fribo ◽  
Istvan Nagy ◽  
Carsten Gotfredsen ◽  
Ana Charrua ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Tolerance ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Oral Glucose ◽  
Transient Receptor Potential Vanilloid ◽  
Low Grade ◽  
Oral Glucose Tolerance ◽  
Transient Receptor ◽  
Low Grade Inflammation

With a global prevalence among adults over 18 years of age approaching 9%, Type 2 diabetes mellitus (T2DM) has reached pandemic proportions and represents a major unmet medical need. To date, no disease modifying treatment is available for T2DM patients. Accumulating evidence suggest that the sensory nervous system is involved in the progression of T2DM by maintaining low-grade inflammation via the vanilloid (capsaicin) receptor, Transient Receptor Potential Vanilloid-1 (TRPV1). In this study, we tested the hypothesis that TRPV1 is directly involved in glucose homeostasis in rodents. TRPV1 receptor knockout mice (Trpv1−/−) and their wild-type littermates were kept on high-fat diet for 15 weeks. Moreover, Zucker obese rats were given the small molecule TRPV1 antagonist, N-(4-Tertiarybutylphenyl)-4-(3-cholorphyridin-2-yl)tetrahydropyrazine-1(2H)-carbox-amide (BCTC), per os twice-a-day or vehicle for eight days. Oral glucose tolerance and glucose-stimulated insulin secretion was improved by both genetic inactivation (Trpv1−/− mice) and pharmacological blockade (BCTC) of TRPV1. In the obese rat, the improved glucose tolerance was accompanied by a reduction in inflammatory markers in the mesenteric fat, suggesting that blockade of low-grade inflammation contributes to the positive effect of TRPV1 antagonism on glucose metabolism. We propose that TRPV1 could be a promising therapeutic target in T2DM by improving glucose intolerance and correcting dysfunctional insulin secretion.

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