Mesenchymal stem cells transplantation ameliorates glomerular injury in streptozotocin-induced diabetic nephropathy in rats via inhibiting oxidative stress

Aims

Mesenchymal stem cells (MSCs) have been demonstrated to be protective in diabetic nephropathy (DN) by reducing albuminuria and attenuating glomerular injury. However, the mechanisms remain unclear. The aim of this study was to explore the effects of MSCs on oxidative stress in DN.

Materials/methods

Streptozotocin-induced diabetic rats received no treatment or treatment with MSCs (2 × 10⁶, via tail vein) for two continuous weeks. Two other control groups received the antioxidant-probucol or insulin. Eight weeks after treatment, physical, biochemical, renal functional and morphological parameters were measured. Glomerular mesangial cells were cultured for the in vitro experiment.

Results

Green fluorescent protein-labeled MSCs were only detected around the glomeruli and near vessels in the kidney. MSCs treatment dramatically reduced blood glucose, urinary albumin excretion, creatinine clearance and renal mass index. The glomerulosclerosis as revealed by periodic acid Schiff staining and expression of collagen I and fibronectin was significantly reduced by MSC treatment. Oxidative stress was also markedly inhibited in the MSCs group. Furthermore, the expression of TGF-β and membrane localization of GLUT1 were also down-regulated by MSCs. MSCs secreted a significant amount of hepatocyte growth factor (HGF). In vitro, MSC conditioned medium inhibited up-regulation of TGF-β expression stimulated by high glucose and HGF neutralizing antibody blocked the inhibitory effect of MSC conditioned medium.

Conclusions

MSC treatment reduced urinary albumin excretion and ameliorated glomerulosclerosis. The mechanisms underlying these effects involved reduced blood glucose levels and cellular glucose uptake mediated by GLUT1, thus inhibiting oxidative stress.     

FKBP5 expression in human adipose tissue increases following dexamethasone exposure and is associated with insulin resistance

Objective

To study effects of dexamethasone on gene expression in human adipose tissue aiming to identify potential novel mechanisms for glucocorticoid-induced insulin resistance.

Materials/methods

Subcutaneous and omental adipose tissue, obtained from non-diabetic donors (10 M/15 F; age: 28–60 years; BMI: 20.7–30.6 kg/m²), was incubated with or without dexamethasone (0.003–3 μmol/L) for 24 h. Gene expression was assessed by microarray and real time-PCR and protein expression by immunoblotting.

Results

FKBP5 (FK506-binding protein 5) and CNR1 (cannabinoid receptor 1) were the most responsive genes to dexamethasone in both subcutaneous and omental adipose tissue (~ 7-fold). Dexamethasone increased FKBP5 gene and protein expression in a dose-dependent manner in both depots. The gene product, FKBP51 protein, was 10-fold higher in the omental than in the subcutaneous depot, whereas the mRNA levels were similar. Higher FKBP5 gene expression in omental adipose tissue was associated with reduced insulin effects on glucose uptake in both depots. Furthermore, FKBP5 gene expression in subcutaneous adipose tissue was positively correlated with serum insulin, HOMA-IR and subcutaneous adipocyte diameter and negatively with plasma HDL-cholesterol. FKBP5 SNPs were found to be associated with type 2 diabetes and diabetes-related phenotypes in large population-based samples.

Conclusions

Dexamethasone exposure promotes expression of FKBP5 in adipose tissue, a gene that may be implicated in glucocorticoid-induced insulin resistance.     

Dynamic induction of pro-angiogenic milieu after transplantation of marrow-derived mesenchymal stem cells in experimental myocardial infarction

Background

Cell-based pro-angiogenic therapy by bone marrow mesenchymal stem cells (MSCs) has been touted as a means to reducing the adverse effects of cardiac remodeling after myocardial infarction (MI). Milieu-dependent regulation of pro-angiogenic potential of MSCs after infarction remains to be elucidated. In this study, the effects of marrow-derived MSCs on the kinetics of angiogenesis signaling factors were investigated in a rabbit model of MI.

Methods

MI was induced in rabbits, and the animals were randomized into two groups (cell transplantation and control, each group with 21 animals). 1 × 10⁶ autologous marrow-derived MSCs were injected into the myocardium of the border zone after transfection with a green fluorescent protein (GFP) lentiviral reporter vector. Control animals received PBS vehicle only. Effect of the transplanted cells on the hearts was evaluated over time by pathological, immunofluorescence, western blotting, immuno-electron microscopy, and echocardiographic analyses.

Results

Transplanted GFP-positive MSCs were enriched with time in the peri-infarct border zone with differentiation potential into three major cell types of the heart, including cardiomyocytes, endothelial cells, and smooth muscle cells, and there was significant augmentation of microvascular density. The transplanted cells could change the milieu of the injured myocardium to increase the expression levels of VEGF as well as the ratio of Ang-2 to Ang-1, and to reduce the ratio of phosphorylated Tie2 to Tie2.

Conclusion

An angiogenesis-promoting milieu was induced after the transplantation of marrow MSCs in the injured myocardium. Compared with the resident cells, the transplanted cells had a greater rate of cellular kinetics in the infarcted myocardium.     

A unifying working hypothesis for juvenile polyposis syndrome and Ménétrier's disease: Specific localization or concomitant occurrence of a separate entity?

Background

Juvenile polyposis syndrome with gastric involvement may mimic Ménétrier's disease, which is correlated to transforming growth factor (TGF)α overproduction and PDX1 upregulation in the gastric fundus.

Aim

We report a family with juvenile polyposis syndrome where one member showed typical features of Ménétrier's disease and concomitant Helicobacter pylori infection.

Methods

We studied a 31-year-old woman belonging to a family with juvenile polyposis syndrome, who exhibited a particular form of hyperplastic gastropathy diagnosed as Ménétrier's disease with Helicobacter pylori infection.

Results

TGFα overexpression and undetectable PDX1 expression were demonstrated in the fundic gastric biopsy specimens. In all affected members of the family we identified a 4-bp deletion in exon 9 of SMAD4 gene, a mutation usually associated with a more virulent form of juvenile polyposis syndrome with a higher incidence of gastric and colonic polyposis.

Conclusion

To explain the association of juvenile polyposis syndrome with Ménétrier's disease we hypothesized a new mechanism that involves TGFβ-SMAD4 pathway inactivation and TGFα overexpression related to Helicobacter pylori infection.     

Attenuated adipose tissue and skeletal muscle inflammation in obese mice with combined CD4+ and CD8+ T cell deficiency

Objectives

High-fat diet (HFD) feeding in mice is characterized by accumulation of αβ T cells in adipose tissue. However, the contribution of αβ T cells to obesity-induced inflammation of skeletal muscle, a major organ of glucose uptake, is unknown. This study was undertaken to evaluate the effect of αβ T cells on insulin sensitivity and inflammatory state of skeletal muscle and adipose tissue in obesity. Furthermore, we investigated whether CD4+IFNγ+ (T_H1) cells are involved in skeletal muscle and adipose tissue metabolic dysfunction that accompanies obesity.

Methods

Mice lacking αβ T cells (T cell receptor beta chain-deficient [TCRb−/−] mice) were fed HFD for 12 weeks. Obesity-induced skeletal muscle and adipose tissue inflammation was assessed by flow cytometry and quantitative RT-PCR. To investigate the effect of T_H1 cells on skeletal muscle and adipose tissue inflammation and metabolic functions, we injected 5 × 10⁵ T_H1 cells or PBS weekly over 12 weeks into HFD-fed TCRb−/− mice. We also cultured C2C12 myofibers and 3T3-L1 adipocytes with T_H1-conditioned medium.

Results

We showed that similar to adipose tissue, skeletal muscle of obese mice have higher αβ T cell content, including T_H1 cells. TCRb−/− mice were protected against obesity-induced hyperglycemia and insulin resistance. We also demonstrated suppressed macrophage infiltration and reduced inflammatory cytokine expression in skeletal muscle and adipose tissue of TCRb−/− mice on HFD compared to wild-type obese controls. Adoptive transfer of T_H1 cells into HFD-fed TCRb−/− mice resulted in increased skeletal muscle and adipose tissue inflammation and impaired glucose metabolism. T_H1 cells directly impaired functions of C2C12 myotubes and 3T3-L1 adipocytes in vitro.

Conclusions

We conclude that reduced adipose tissue and skeletal muscle inflammation in obese TCRb−/− mice is partially attributable to the absence of T_H1 cells. Our results suggest an important role of T_H1 cells in regulating inflammation and insulin resistance in obesity.     

Circulating fetuin-A levels are not affected by short and long-term energy deprivation and/or by leptin administration

Objective

Fetuin-A may mediate cross-talk between the liver and adipose tissue. We studied the physiologic regulation of fetuin-A and explored its potential regulation by leptin.

Design and Methods

Fetuin-A levels were measured in three interventional studies as well as in in vitro experiments. Study 1: 15 lean subjects received placebo or physiologic replacement-dose recombinant human leptin (metreleptin) following short term complete caloric deprivation to induce severe hypoleptinemia; Study 2: 7 women with relative leptin deficiency due to strenuous exercise or low weight received 3 months of metreleptin; Study 3: 17 women with relative leptin deficiency were randomized to receive metreleptin or placebo over 9 months. In study 4 human hepatoma Hep G2 cells were treated with leptin. Fetuin-A mRNA expression and secretion were measured.

Results

Complete caloric deprivation significantly decreased leptin but had no effect on fetuin-A levels. Normalizing leptin levels with metreleptin in hypoleptinemic subjects had no effect on circulating fetuin-A levels. Leptin treatment had no effect on fetuin-A mRNA expression and secretion in vitro.

Conclusions

Circulating fetuin-A levels are not affected by short and long-term energy deprivation. Furthermore, both in vivo and in vitro experiments confirm that fetuin-A is not regulated by leptin.     

Bioluminescence imaging of cardiomyogenic and vascular differentiation of cardiac and subcutaneous adipose tissue-derived progenitor cells in fibrin patches in a myocardium infarct model

Background

Adipose tissue-derived progenitor cells (ATDPCs) isolated from human cardiac adipose tissue are useful for cardiac regeneration in rodent models. These cells do not express cardiac troponin I (cTnI) and only express low levels of PECAM-1 when cultured under standard conditions. The purpose of the present study was to evaluate changes in cTnI and PECAM-1 gene expression in cardiac ATDPCs following their delivery through a fibrin patch to a murine model of myocardial infarction using a non-invasive bioluminescence imaging procedure.

Methods and results

Cardiac and subcutaneous ATDPCs were doubly transduced with lentiviral vectors for the expression of chimerical bioluminescent–fluorescent reporters driven by constitutively active and tissue-specific promoters (cardiac and endothelial for cTnI and PECAM-1, respectively). Labeled cells mixed with fibrin were applied as a 3-D fibrin patch over the infarcted tissue. Both cell types exhibited de novo expression of cTnI, though the levels were remarkably higher in cardiac ATDPCs. Endothelial differentiation was similar in both ATDPCs, though cardiac cells induced vascularization more effectively. The imaging results were corroborated by standard techniques, validating the use of bioluminescence imaging for in vivo analysis of tissue repair strategies. Accordingly, ATDPC treatment translated into detectable functional and morphological improvements in heart function.

Conclusions

Both ATDPCs differentiate to the endothelial lineage at a similar level, cardiac ATDPCs differentiated more readily to the cardiomyogenic lineage than subcutaneous ATDPCs. Non-invasive bioluminescence imaging was a useful tool for real time monitoring of gene expression changes in implanted ATDPCs that could facilitate the development of procedures for tissue repair.     

Comparison of human amniotic fluid-derived and umbilical cord Wharton's Jelly-derived mesenchymal stromal cells: Characterization and myocardial differentiation capacity

Objective To compare the characterization and myocardial differentiation capacity of amniotic fluid-derived mesenchymal stromal cells (AF MSCs) and umbilical cord Wharton's Jelly-derived mesenchymal stromal cells (WJ MSCs). Methods The human AF MSCs were cultured from amniotic fluid samples obtained by amniocentesis. The umbilical cord WJ MSCs were obtained from Wharton's Jelly of umbilical cords of infants delivered full-term by normal labor. The morphology, growth curves, and analyses by flow cytometry of cell surface markers were compared between the two types of cells. Myocardial genes (GATA-4, c-TnT, α-actin, and Cx43) were detected by real-time PCR and the corresponding protein expressions were detected by Western blot analysis after myocardial induced in AF MSCs and WJ MSCs. Results Our findings revealed AF MSCs and WJ MSCs shared similar morphological characteristics of the fibroblastoid shape. The AF MSCs were easily obtained than the WJ MSCs and had a shorter time to reach adherence of 2.7 ± 1.6 days to WJ MSCs of 6.5 ± 1.8 days. The growth curves by MTT cytotoxic assay showed the AF MSCs had a similar proliferative capacity at passage 5 and passage 10. However, the proliferative capacities of WJ MSCs were decreased at 5 passage relative to 10 passage. Both AF stem cells and WJ stem cells had the characteristics of mesenchymal stromal cells with some characteristics of embryonic stem cells. They express CD29 and CD105, but not CD34. They were positive for Class I major histocompatibility (MHC I) antigens (HLA-ABC), and were negative, or mildly positive, for MHC Class II (HLA-DR) antigen. Oct-4 was positive in all the two cells types. Both AF MSCs and WJ MSCs could differentiate along myocardium. The differentiation capacities were detected by the expression of GATA-4, c-TnT, α-actin, Cx43 after myocardial induction. Conclusions Both AF MSCs and WJ MSCs have the potential clinical application for myogenesis in cardiac regenerative therapy.     

Hepatic overexpression of the prodomain of furin lessens progression of atherosclerosis and reduces vascular remodeling in response to injury

Objective

Atherosclerosis is a complex disease, involving elevated LDL-c, lipid accumulation in the blood vessel wall, foam cell formation and vascular dysfunction. Lowering plasma LDL-c is the cornerstone of current management of cardiovascular disease. However, new approaches which reduce plasma LDL-c and lessen the pathological vascular remodeling occurring in the disease should also have therapeutic value. Previously, we found that overexpression of profurin, the 83-amino acid prodomain of the proprotein convertase furin, lowered plasma HDL levels in wild-type mice. The question that remained was whether it had effects on apolipoprotein B (ApoB)-containing lipoproteins.

Methods

Adenovirus mediated overexpression of hepatic profurin in Ldlr^−/−mice and wild-type mice were used to evaluate effects of profurin on ApoB-containing lipoproteins, atherosclerosis and vascular remodeling.

Results

Hepatic profurin overexpression resulted in a significant reduction in atherosclerotic lesion development in Ldlr^−/−mice and a robust reduction in plasma LDL-c. Metabolic studies revealed lower secretion of ApoB and triglycerides in VLDL particles. Mechanistic studies showed that in the presence of profurin, hepatic ApoB, mainly ApoB100, was degraded by proteasomes. There was no effect on ApoB mRNA expression. Importantly, short-term hepatic profurin overexpression did not result in hepatic lipid accumulation. Blood vessel wall thickening caused by either wire-induced femoral artery injury or common carotid artery ligation was reduced. Profurin expression inhibited proliferation and migration in vascular smooth muscle cells in vitro.

Conclusion

These results indicate that a profurin-based therapy has the potential to treat atherosclerosis by improving metabolic lipid profiles and reducing both atherosclerotic lesion development and pathological vascular remodeling.     

Characterization of the human nucleus pulposus cell phenotype and evaluation of novel marker gene expression to define adult stem cell differentiation

Objective

Development of stem cell therapies for regenerating the nucleus pulposus (NP) are hindered by the lack of specific markers by which to distinguish NP cells from articular chondrocytes (ACs). The purpose of this study was to define the phenotype profile of human NP cells using gene expression profiling and to assess whether the identified markers could distinguish mesenchymal stem cell (MSC) differentiation to a correct NP cell phenotype.

Methods

Affymetrix MicroArray analyses were conducted on human NP cells and ACs, and differential expression levels for several positive (NP) and negative (AC) marker genes were validated by real‐time quantitative polymerase chain reaction (PCR) analysis. Novel marker gene and protein expression was also assessed in human bone marrow–derived MSCs (BM‐MSCs) and adipose tissue–derived MSCs (AD‐MSCs) following differentiation in type I collagen gels.

Results

Analysis identified 12 NP‐positive and 36‐negative (AC) marker genes that were differentially expressed ≥20‐fold, and for a subset of them (NP‐positive genes PAX1, FOXF1, HBB, CA12, and OVOS2; AC‐positive genes GDF10, CYTL1, IBSP, and FBLN1), differential expression was confirmed by real‐time quantitative PCR. Differentiated BM‐MSCs and AD‐MSCs demonstrated significant increases in the novel NP markers PAX1 and FOXF1. AD‐MSCs lacked expression of the AC markers IBSP and FBLN1, whereas BM‐MSCs lacked expression of the AC marker IBSP but expressed FBLN1.

Conclusion

This study is the first to use gene expression profiling to identify the human NP cell phenotype. Importantly, these markers can be used to determine the in vitro differentiation of MSCs to an NP‐like, rather than an AC‐like, phenotype. Interestingly, these results suggest that AD‐MSCs may be a more appropriate cell type than BM‐MSCs for use in engineering intervertebral disc tissue.

     

La grasa epicárdica se relaciona con la visceral,el síndrome metabólico y la resistencia a la insulina en mujeres menopáusicas

Introduction and objectives

Epicardial adipose tissue has been associated with several obesity-related parameters and with insulin resistance. Echocardiographic assessment of this tissue is an easy and reliable marker of cardiometabolic risk. However, there are insufficient studies on the relationship between epicardial fat and insulin resistance during the postmenopausal period, when cardiovascular risk increases in women. The objective of this study was to examine the association between epicardial adipose tissue and visceral adipose tissue, waist circumference, body mass index, and insulin resistance in postmenopausal women.

Methods

A cross sectional study was conducted in 34 postmenopausal women with and without metabolic syndrome. All participants underwent a transthoracic echocardiogram and body composition analysis.

Results

A positive correlation was observed between epicardial fat and visceral adipose tissue, body mass index, and waist circumference. The values of these correlations of epicardial fat thickness overlying the aorta-right ventricle were r = 0.505 (P < .003), r = 0.545 (P < .001), and r = 0.515 (P < .003), respectively. Epicardial adipose tissue was higher in postmenopausal women with metabolic syndrome than in those without this syndrome (mean [standard deviation], 544.2 [122.9] vs 363.6 [162.3] mm ²; P = .03).

Conclusions

Epicardial fat thickness measured by echocardiography was associated with visceral adipose tissue and other obesity parameters. Epicardial adipose tissue was higher in postmenopausal women with metabolic syndrome. Therefore, echocardiographic assessment of epicardial fat may be a simple and reliable marker of cardiovascular risk in postmenopausal women.Full English text available from:www.revespcardiol.org/en     

Markers of endothelial cell dysfunction are increased in human omental adipose tissue from women with pre-existing maternal obesity and gestational diabetes

Objective

To determine the effect of maternal obesity and gestational diabetes mellitus (GDM) on the expression and release of genes involved in endothelial cell dysfunction in human placenta and omental adipose tissue.

Materials/Methods

Human placenta and omental adipose tissue were obtained from non-obese and obese normal glucose tolerant (NGT) women and women with GDM at the time of Caesarean section. Quantitative RT-PCR was performed to determine the level of expression. Tissue explants were performed to determine the release of proteins of interest.

Results

There was no effect of pre-existing maternal obesity or GDM on placental gene expression or secretion of members of the VEGF family members (PLGF and VEGF-A expression and secretion; sFlt-1 release; VEGFR1 and VEGFR2 mRNA expression); FGFR1 mRNA expression, FGF2 mRNA expression and secretion; endoglin mRNA expression and secretion (sEng); and the adhesion molecules ICAM-1 and VCAM-1. On the other hand, in omental adipose tissue, pre-existing maternal obesity and GDM were associated with increased gene expression of PLGF, endoglin and ICAM-1 and increased secretion of PLGF, sFlt-1, FGF2, sEng and sICAM-1. There was, however, no effect of maternal pre-existing obesity and GDM on VEGF-A, VEGFR1, VEGFR2, FGFR1 and VCAM-1 expression or secretion.

Conclusions

This study demonstrated the presence of abnormal expression and secretion of angiogenic proteins and adhesion molecules in omental adipose tissue, but not placenta, from pregnant women with GDM and pre-existing maternal obesity. Increased angiogenic and adhesion molecules released from adipose tissue may affect angiogenesis, inflammation and or lipid and glucose metabolism in both mum and her offspring.     

Clonal diversity among Burkholderia cepacia complex isolates from cystic fibrosis patients in a reference unit

Introduction

The epidemiology of Burkholderia cepacia complex (Bcc) in cystic fibrosis (CF) is not widely known.

Methods

All CF patients with Bcc between 2002 and 2011 were reviewed, and a molecular analysis of isolates was performed.

Results

The prevalence of Bcc infection was 7.2% (18/250). Molecular analysis of 16 Bcc isolates showed 5 species (7 B. contaminans, 6 B. cepacia, 1 B. cenocepacia, 1 B. multivorans, and 1 B. stabilis) and 13 sequence types. There were no cases of cross-transmission.

Conclusion

A high diversity of Bcc species was found in infected CF patients.     

GMP-adapted overexpression of CXCR4 in human mesenchymal stem cells for cardiac repair

Background

Human mesenchymal stem cells (MSC) have been utilized for cardiac regeneration after myocardial damage. Their clinical effects are marginal and only a minority of administered cells could make their way into the myocardium. The chemokine receptor CXCR4 has been identified as crucial for migration and homing of stem cells. In this study we overexpressed CXCR4 on human MSC to improve cell trafficking and tissue repair.

Methods

Human MSC were isolated from the spongiosa of tibia and femur as well as from pelvic bone marrow. MSC were characterized by differentiation assays and FACS analysis. CXCR4 was overexpressed by mRNA-nucleofection. Intracellular signaling was analyzed to demonstrate functionality of CXCR4. The modified Boyden chamber, wounding assays and time lapse microscopy were utilized to investigate MSC migration.

Results

MSC did not express relevant amounts of CXCR4 spontaneously. CXCR4 could be overexpressed in 93% of MSC with a cell viability of 62%. Functionality of the overexpressed CXCR4 was demonstrated by a significant cytosolic Ca²⁺ increase and activation of different MAP kinases followed by SDF-1α stimulation. In contrast no improvement of cell migration could be observed. There was a strong basal MSC chemokinesis independent from CXCR4 expression.

Conclusions

CXCR4 could be effectively overexpressed in human MSC by mRNA-nucleofection. Despite functionality of CXCR4 MSC were characterized by a strong basal chemokinesis that could not be further enhanced by CXCR4 overexpression. As isolation, culture and nucleofection of pelvic bone marrow-derived MSC basically fulfill the GMP-requirements our approach seems suited for an in vivo application in patients.     

TRIB3 alters endoplasmic reticulum stress-induced β-cell apoptosis via the NF-κB pathway

Objective

To examine the effect of TRIB3 on endoplasmic reticulum stress induced β-cell apoptosis and to investigate the mechanism with a specific emphasis on the role of NF-κB pathway.

Materials/Methods

We investigated the effect of TRIB3 on ER stress-induced β-cell apoptosis in INS-1 cells and primary rodent islets. The potential role of TRIB3 in ER stress inducer thapsigargin (Tg)-induced β-cell apoptosis was assessed using overexpression and siRNA knockdown approaches. Inducible TRIB3 β-cells, regulated by the tet-on system, were used for sub-renal capsule transplantation in streptozotocin (STZ)-diabetic mice, to study the effect of TRIB3 on ER stress-induced β-cell apoptosis in vivo. Apoptosis was determined by TUNEL staining both in vivo and in vitro, while the molecular mechanisms of NF-κB activation were investigated.

Results

TRIB3 was induced in ER-stressed INS-1 cells and rodent islets, and its overexpression was accompanied by increased β-cell apoptosis. Specifically, TRIB3 overexpression enhanced Tg-induced INS-1 derived β-cell apoptosis both in vitro and in sub-renal capsular transplantation animal model. Additionally, knockdown of Trib3 blocked Tg-induced apoptosis. Mechanistically, the induction of TRIB3 during ER stress resulted in the activation of NF-κB and aggravated INS-1 derived β-cell apoptosis, while inhibiting the NF-κB pathway significantly abrogated this response and prevented β-cell apoptosis, both in vitro and in sub-renal capsular transplantation animal model.

Conclusion

TRIB3 mediated ER stress-induced β-cell apoptosis via the NF-κB pathway.     

Association between low SIRT1 expression in visceral and subcutaneous adipose tissues and metabolic abnormalities in women with obesity and type 2 diabetes

Aims

To assess the importance of adipose tissue sirtuin 1 (SIRT1) in the regulation of whole-body metabolism in humans with obesity and type 2 diabetes.

Methods

In total, 19 non-diabetic obese women, 19 type 2 diabetic women undergoing gastric bypass surgery, and 27 normal-weight women undergoing gynecological surgery (total 65 women) were enrolled. Their anthropometric variables, abdominal fat distribution and metabolic parameters, serum adiponectin concentrations, and SIRT1 mRNA and protein and adiponectin mRNA expressions in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured.

Results

SIRT1 mRNA levels in VAT and SAT were similar and these levels were suppressed in obese and type 2 diabetic women compared to normal-weight subjects. These decreases in SIRT1 expression were observed in both adipocytes and non-fat cells. There was a strong association between adipose tissue SIRT1 mRNA and protein levels. Adipose SIRT1 expression correlated inversely with HOMA-IR and other insulin resistance-related parameters. Adipose SIRT1 and adiponectin mRNA expression correlated very strongly and positively. SIRT1 mRNA level in VAT correlated inversely with visceral obesity whereas its expression in SAT correlated negatively with body mass index.

Conclusions

Adipose tissue SIRT1 may play a key role in the regulation of whole body metabolic homeostasis in humans. Downregulation of SIRT1 in VAT may contribute to the metabolic abnormalities that are associated with visceral obesity.