scholarly journals Protocatechuic acids protects against high glucose- induced insulin resistance in human visceral adipose tissue

2016 ◽  
Vol 62 (5) ◽  
pp. 45-46
Author(s):  
Paulina Ormazabal ◽  
Beatrice Scazzocchio ◽  
Rosaria Varì ◽  
Annunziata Iacovelli ◽  
Roberta Masella
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Visceral Adipose Tissue ◽  
High Glucose ◽  
Protective Role ◽  
Insulin Sensitizer ◽  
20 Nm ◽  
Visceral Adipose

Adipocytes exposed to high glucose concentrations exhibit impaired insulin signaling. Binding of insulin to its membrane receptor activates insulin metabolic pathway leading to IRS-1 and AKT phosphorylations. The accumulation of visceral adipose tissue (VAT) correlates with insulin resistance and metabolic syndrome. Anthocyanins (ACN) are bioactive food compounds of great nutritional interest. We have shown that protocatechuic acid (PCA), a major metabolite of ACN, might exert insulin-sensitizer activities in human visceral adipose tissue. The aim of this work was to define the protective role of PCA against insulin-resistance induced by high glucose in VAT.Methodology: VAT obtained from control subject (BMI≤25) were separated in four experimental groups: i) PCA: samples treated for 24 h with 100 μM PCA, ii) GLU: VAT treated with 30 mM glucose for 24 h, iii) PCA+GLU: 1 hour incubation with 100 μM PCA before adding glucose (30 mM, 24 h), iv) CTR: vehicle. After treatment, VAT groups were (or not) acutely stimulated with insulin (20 nM, 20 min). Tyr-IRS-1 and Ser-Akt phosphorylations were assessed by Western blotting (WB) in basal or insulin stimulated tissues in all experimental groups. Samples were assessed for IRS-1, IR, Akt and GLUT4 protein content by WB. Results: No differences in protein contents between experimental groups were found. GLU tissues showed a lower increment in insulin-stimulated phosphorylation of IRS-1 and Akt compared to CTR and PCA samples. This impaired activation was completely reversed by the pretreatment with PCA.Conclusion: An in-vitro insulin-resistance condition induced by high glucose was established in biopsies of VAT. PCA restores the ability of GLU-tissues to fully respond to insulin by increasing IRS-1 and Akt phosphorylations. These results confirm the insulin-sensitizer effect of PCA on VAT previously reported by our group. An anthocyanin rich diet might help to protect against insulin-resistance in VAT.

scholarly journals Role of ceramide-to-dihydroceramide ratios for insulin resistance and non-alcoholic fatty liver disease in humans

2020 ◽  
Vol 8 (2) ◽  
pp. e001860
Author(s):  
Maria Apostolopoulou ◽  
Ruth Gordillo ◽  
Sofiya Gancheva ◽  
Klaus Strassburger ◽  
Christian Herder ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Visceral Adipose Tissue ◽  
Fatty Liver Disease ◽  
Liver Fat ◽  
Liver Fat Content ◽  
Alcoholic Fatty Liver ◽  
Visceral Adipose ◽  
Alcoholic Fatty Liver Disease

IntroductionSphingolipid accumulation has been linked to obesity, type 2 diabetes and non-alcoholic fatty liver disease (NAFLD). A recent study showed that depletion of dihydroceramide desaturase-1 (DES-1) in adipose and/or liver tissue decreases ceramide-to-dihydroceramide ratios (ceramide/dihydroceramide) in several tissues and improves the metabolic profile in mice. We tested the hypothesis that ceramide/dihydroceramide would also be elevated and relate positively to liver fat content and insulin resistance in humans.Research design and methodsThus, we assessed total and specific ceramide/dihydroceramide in various biosamples of 7 lean and 21 obese volunteers without or with different NAFLD stages, who were eligible for abdominal or bariatric surgery, respectively. Biosamples were obtained from serum, liver, rectus abdominis muscle as well as subcutaneous abdominal and visceral adipose tissue during surgery.ResultsSurprisingly, certain serum and liver ceramide/dihydroceramide ratios were reduced in both obesity and non-alcoholic steatohepatitis (NASH) and related inversely to liver fat content. Specifically, hepatic ceramide/dihydroceramide (species 16:0) related negatively to hepatic mitochondrial capacity and lipid peroxidation. In visceral adipose tissue, ceramide/dihydroceramide (species 16:0) associated positively with markers of inflammation.ConclusionThese results failed to confirm the relationships of ceramide/dihydroceramide in humans with different degree of insulin resistance. However, the low hepatic ceramide/dihydroceramide favor a role for dihydroceramide accumulation in NASH, while a specific ceramide/dihydroceramide ratio in visceral adipose tissue suggests a role of ceramides in obesity-associated low-grade inflammation.

Abstract 3592: Early Detection Of CD4-positive Lymphocytes In Adipose Tissue During The Development Of Insulin Resistance

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Katharina Hess ◽  
Nikolaus Marx ◽  
Martin Wabitsch ◽  
Thomas Skurk ◽  
Hans Hauner ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Visceral Adipose Tissue ◽  
Immunohistochemical Staining ◽  
Human Adipose Tissue ◽  
Adipose Tissue Inflammation ◽  
Rt Pcr ◽  
Tissue Inflammation ◽  
Visceral Adipose

Background: Adipose tissue inflammation may play a critical role in the pathogenesis of insulin resistance (IR) and arteriosclerosis. Previous work has mainly focused on the role of macrophages in human adipose tissue, but little is known about pro-inflammatory T-lymphocytes. Therefore the present study examined the role of CD4-positive lymphocytes in adipose tissue inflammation and IR. Results: Both, CD4-positive lymphocytes and macrophages are present in human visceral adipose tissue as determined by immunohistochemical staining. Most macrophages were HLA-DR positive, reflecting activation through IFNγ, a cytokine released from CD4-positive lymphocytes. Furthermore, SDF-1α, a T-cell chemotactic protein, was also detectable in human adipose tissue. RT-PCR analyses confirmed the expression of IFNγ and SDF1α in visceral adipose tissue. Freshly isolated human adipocytes as well SGBS adipocyte cells express SDF-1α with a down regulation of its expression during adipocyte differentiation in both cell types. In a mouse model of IR, high fat diet induced IR already after 5 weeks which was associated with a marked lymphocyte infiltration in visceral adipose tissue as determined by immunohistochemical staining and RT-PCR. In contrast, macrophages were absent after 5 weeks of diet but could be detected at week 10, suggesting early infiltration of lymphocytes during the development of IR. Conclusion: Pro-inflammatory T-lymphocytes are present in visceral adipose tissue and may contribute to local inflammatory cell activation before the appearance of macrophages. These data suggest that lymphocytes may play an important role in the initiation and perpetuation of adipose tissue inflammation as well as the development of insulin resistance.

scholarly journals Elevated serum uric acid is a facilitating mechanism for insulin resistance mediated accumulation of visceral adipose tissue

2020 ◽  
Author(s):  
Luisa Fernández-Chirino ◽  
Neftali Eduardo Antonio-Villa ◽  
Arsenio Vargas-Vázquez ◽  
Paloma Almeda-Valdés ◽  
Donají Gómez-Velasco ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Uric Acid ◽  
Serum Uric Acid ◽  
Visceral Adipose Tissue ◽  
Visceral Obesity ◽  
Causal Mechanism ◽  
Mediation Analyses ◽  
Bidirectional Relationship ◽  
Visceral Adipose

BACKGROUND: Serum uric acid (SUA) has a relationship with cardiometabolic conditions such as insulin resistance (IR) and visceral adipose tissue (VAT) accumulation. Here, we aimed to clarify the nature of this relationship and the underlying causality mechanism. METHODS: We conducted a population-based cross-sectional study comprising 8,504 subjects joining both NHANES 2003-2004 and 2011-2012 cycles and ENSANUT Medio Camino 2016. We performed mixed effects linear regression models using HOMA2-IR, adipoIR, and METS-VF as indicators of IR and VAT accumulation. Furthermore, we performed mediation analyses to assess a potential causal mechanism and ROC curves to establish cut-off points for identification of IR and visceral obesity using SUA. Finally, with an additional dataset comprised of 226 subjects with both euglycemic hyperinsulinemic clamp (EHC) and dual X-ray absorptiometry (DXA) measurements for IR and VAT accumulation, we performed a network of confirmatory mediation analyses. RESULTS:We found that SUA has a mediating role inside the bidirectional relationship between IR and visceral obesity, and it is part of an underlying causality mechanism which includes adiponectin. The proportion of the mechanism mediated by SUA is greater when stated that IR (in either peripheral or adipose tissue) leads to VAT accumulation (14.90%[13.20%-17.00%] and 15.54%[13.61% - 18.00%] to 4.88%[3.06%-7.00%] and 8.13%[5.91% - 10.00%]) instead of the opposite direction. This result was confirmed by mediation analyses using gold-standard measurements. CONCLUSIONS:Elevated SUA acts as mediator inside the bidirectional relationship between IR andVAT accumulation. Its role appears to be larger when considering adipose tissue IR as the promoter for VAT accumulation.

scholarly journals Abdominal Subcutaneous and Visceral Adipose Tissue and Insulin Resistance in the Framingham Heart Study

Obesity ◽  
2010 ◽  
Vol 18 (11) ◽  
pp. 2191-2198 ◽  
Author(s):  
Sarah R. Preis ◽  
Joseph M. Massaro ◽  
Sander J. Robins ◽  
Udo Hoffmann ◽  
Ramachandran S. Vasan ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Visceral Adipose Tissue ◽  
Framingham Heart Study ◽  
Heart Study ◽  
Visceral Adipose

Abstract P232: Worse Cardiometabolic Health in African Immigrants than African-Americans: Reconsideration of the Healthy Immigrant Effect

Circulation ◽  
2014 ◽  
Vol 129 (suppl_1) ◽  
Author(s):  
Anne E Sumner ◽  
Michelle Y O'Connor ◽  
Caroline K Thoreson ◽  
Madia Ricks ◽  
Amber B Courville ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
African Americans ◽  
Visceral Adipose Tissue ◽  
African Immigrants ◽  
Cardiometabolic Health ◽  
Sensitivity Index ◽  
Healthy Immigrant Effect ◽  
Immigrant Effect ◽  
Visceral Adipose

In decades past, African immigrants were considered to have better cardiometabolic health than African Americans. Whether this health advantage continues to exist in the 21st century is unknown. To explore differences in markers of cardiometabolic health, oral glucose tolerance tests, blood pressure (BP), visceral adipose tissue (VAT) volume and the waist circumference (WC) which predicts insulin resistance were compared in 210 men (134 African immigrants, 76 African Americans, mean age 36±9y (mean±SD), range 20-64y) who self-identified as healthy. Insulin resistance was defined by the lowest quartile of the insulin sensitivity index (SI≤2•28mU/L-1.min-1). Receiver operating characteristic curves and the Youden Index were used to identify the WC which optimally predicts insulin resistance. BMI was lower in African immigrants than African Americans (27.4±3.9 vs. 29.3±5.5kg/m2, P<0.01). Adjusting for BMI, WC did not differ between groups (93±5 vs. 94±5cm, P=0.55); but African immigrants had more visceral adipose tissue (VAT) (P<0.001) higher BP (P≤0.01), higher fasting glucose (P≤0.001) and 2h glucose (P<0.001) as well as a higher prevalence of previously undiagnosed diabetes (7% (9 of 134) vs. 0% (0 of 76), P<0.01) and pre-diabetes (35% (47 of 134) vs. 22% (17 of 76), P<0.01). Degree of insulin resistance did not differ in African immigrants and African Americans (4.17±2.88 vs. 4.24±2.61 (mU/L)-1 .min-1, P=0.88). Yet, the WC which optimally predicted insulin resistance was lower in African immigrants than African Americans, specifically 92 cm and 102 cm, respectively. As African immigrants had higher VAT, BP and glucose levels than African Americans, the healthy immigrant effect may no longer be a valid concept. As insulin resistance occurred at a lower WC in African immigrants than African Americans, lower BMI in African immigrants does not appear to provide protection from cardiometabolic risk.

Abstract 14315: New Insights Into the Mechanisms of Sepsis: The Role of Proprotein Convertase Subtilisin/kexin Type 9 as a Key Regulator of Pathogen Toxin Clearance

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Elena Topchiy ◽  
Yingjin Wang ◽  
John Boyd ◽  
Keith R Walley
Keyword(s):  
Adipose Tissue ◽  
Visceral Adipose Tissue ◽  
Ex Vivo ◽  
Fluorescent Microscopy ◽  
Hepatic Uptake ◽  
Cardiovascular Complications ◽  
Proprotein Convertase ◽  
Bacterial Endotoxins ◽  
Visceral Adipose

Background: To prevent severe inflammation during infection, the patient must quickly clear bacterial endotoxins from the circulation before they accumulate and are able to interact with immune cells and vascular endothelium, and induce inflammatory organ failure. Bacterial endotoxins are carried within lipoprotein particles. Thus, one mechanism of action for sepsis treatments could be acceleration of lipoprotein clearance by adipocytes and hepatocytes. Proprotein convertase subtilisin/kexin type 9 (PCSK9) decreases the rate of lipoprotein clearance. We have recently reported that reduced function of PCSK9 improves outcome and prevents cardiovascular complications associated with sepsis. Hypothesis: PCSK9 inhibits LDL associated LPS clearance through hepatic LDLR and VLDL associated LPS clearance through adipose VLDLR. Methods and Results: Using siRNA against the LDLR in HepG2 hepatocytes decreased uptake of fluorescently labeled LPS (fLPS) after 48 hours by 1.50±0.10 fold (n=3, p<0.05). Addition of recombinant PCSK9 in the absence of LDLR did not alter uptake of LPS. We confirmed that hepatic uptake of LPS is exclusively via the LDLR by fluorescent microscopy of ex vivo LPS treated primary hepatocytes isolated from LDLR -/- mice. To address the importance of the LDLR upon clearance of LPS from plasma, we injected fLPS into the portal vein of LDLR-/-, PCSK9-/- and wild type mice (WT). Compared to WT, LDLR-/- mice had 36±13% (n=9, p<0.001) increase in plasma LPS after 1 hour, whereas PCSK9-/- show a significant decrease (28±4%, n=9, p<0.001) in plasma LPS. LDLR-/-, but not PCSK9-/- mice showed 46±7% decrease (n=10, p<0.05) in hepatic uptake. On the other hand, compared to the WT PCSK9-/- mice had 200±35% (n=8, p<0.001) increase in LPS uptake by visceral adipose tissue whereas LDLR-/- had no effect compared to WT mice. To further investigate LPS uptake by adipose tissue we injected flLPS into the tail vein of VLDLR-/- and WT mice. VLDLR-/- mice had 33±6% (n=10, p<0.001) decrease in visceral adipose tissue uptake, with no significant change in hepatic uptake. Conclusions: Expression of hepatic LDLR and adipose VLDLR is mainly regulated by PCSK9 and both play important role in clearing LPS from circulation.

scholarly journals Collagen 24 α1 Is Increased in Insulin-Resistant Skeletal Muscle and Adipose Tissue

2020 ◽  
Vol 21 (16) ◽  
pp. 5738
Author(s):  
Xiong Weng ◽  
De Lin ◽  
Jeffrey T. J. Huang ◽  
Roland H. Stimson ◽  
David H. Wasserman ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Insulin Resistant ◽  
Global View ◽  
Novel Association ◽  
Visceral Adipose ◽  
Subcutaneous Adipose

Aberrant extracellular matrix (ECM) remodelling in muscle, liver and adipose tissue is a key characteristic of obesity and insulin resistance. Despite its emerging importance, the effective ECM targets remain largely undefined due to limitations of current approaches. Here, we developed a novel ECM-specific mass spectrometry-based proteomics technique to characterise the global view of the ECM changes in the skeletal muscle and liver of mice after high fat (HF) diet feeding. We identified distinct signatures of HF-induced protein changes between skeletal muscle and liver where the ECM remodelling was more prominent in the muscle than liver. In particular, most muscle collagen isoforms were increased by HF diet feeding whereas the liver collagens were differentially but moderately affected highlighting a different role of the ECM remodelling in different tissues of obesity. Moreover, we identified a novel association between collagen 24α1 and insulin resistance in the skeletal muscle. Using quantitative gene expression analysis, we extended this association to the white adipose tissue. Importantly, collagen 24α1 mRNA was increased in the visceral adipose tissue, but not the subcutaneous adipose tissue of obese diabetic subjects compared to lean controls, implying a potential pathogenic role of collagen 24α1 in obesity and type 2 diabetes.

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