Obesity associated with type 2 diabetes mellitus is linked to decreased PC1/3 mRNA expression in the Jejunum.

BACKGROUND: Bariatric surgery is the most effective therapeutic option for obesity and its complications, especially in type 2 diabetes. The aim of this study was to investigate the messenger RNA (mRNA) gene expression of proglucagon, glucose-dependent insulinotropic peptide (GIP), prohormone convertase 1/3 (PC1/3), and dipeptidyl peptidase-IV (DPP-IV) in jejunum cells of the morbidly obese (OB) non type 2 diabetes mellitus (NDM2) and type 2 diabetes mellitus (T2DM), to determine the molecular basis of incretin secretion after bariatric surgery. METHODS: Samples of jejunal mucosa were obtained from 20 NDM2 patients: removal of a section of the jejunum about 60 cm distal to the ligament of Treitz and 18 T2DM patients: removal of a section of the jejunum about 100 cm distal to the ligament of Treitz. Total RNA was extracted using TRIzol. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) was carried out. Samples were sequenced to PC1/3 by ACTGene Análises Moleculares Ltd. Immuno content was quantified with a fluorescence microscope. RESULTS: T2DM showed decreased PC1/3 mRNA expression in the primers tested (primer a, p=0.014; primer b, p=0.048). Many patients (36.5 %) did not express PC1/3 mRNA. NDM2 and T2DM subjects showed nonsignificantly different proglucagon, GIP, and DPP-IV mRNA expression. The immuno contents of glucagon-like peptide-1 and GIP decreased in T2DM jejunum, but incubation with high glucose stimulated the immuno contents. CONCLUSIONS: The results suggest that bioactivation of pro-GIP and proglucagon could be impaired by the lower expression of PC1/3 mRNA in jejunum cells of obese patients with T2DM. However, after surgery, food could activate this system and improve glucose levels in these patients.

Parallel down-regulation of FOXO1, PPARγ and adiponectin mRNA expression in visceral adipose tissue of class III obese individuals.

OBJECTIVE: Adipose tissue is responsible for secretion of several cytokines that mediate systemic effects on obesity and insulin resistance. Subcutaneous abdominal adipose tissue (SAT) and visceral adipose tissue (VAT) are metabolically different and have differences in their gene expression profile. Our study evaluated the expression of adiponectin, FOXO1, PPARγ, and SIRT1 in VAT and SAT of non-obese and class III obese subjects. METHODS: The adipose tissue samples were obtained by surgery. Reverse transcripts of studied genes were determined by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: Comparing the different lipid depots, adiponectin expression was lower only in VAT of obese individuals (p = 0.043); FOXO1 and PPARγ levels were decreased in VAT of both groups. When non-obese and obese were compared, only adiponectin expression was lower in SAT and in VAT of obese subjects (p = 0.004 and p = 0.002, respectively). No difference was found with regard to SIRT1 levels in VAT or SAT in both groups. FOXO1 expression in SAT of obese subjects had a negative correlation with age (r = -0.683; p = 0.029) and triglyceride serum levels (r = -0.794; p = 0.006). CONCLUSION: The decrease mRNA expression of this genes in VAT, responsible for central adiposity, may be associated with an increased risk of obesity and co-morbidities.

Resveratrol upregulated SIRT1, FOXO1, and adiponectin and downregulated PPARγ1-3 mRNA expression in human visceral adipocytes.

BACKGROUND: The SIRT1 enzyme is involved in adipose tissue (AT) lipolysis. FOXO1 is a protein that plays a significant role in regulating metabolism. Adiponectin is an adipokine, secreted by the AT, which has been considered to have an antiobesity function. PPARγ is one of the key actors in adipocytes differentiation. This study was undertaken to investigate whether resveratrol can regulate SIRT1, FOXO1, adiponectin, PPARγ1-3, and PPARß/δ in human AT. METHODS: The effects of resveratrol were analyzed in freshly isolated adipocytes prepared from visceral fat tissue samples obtained during bariatric surgery. Genes messenger ribonucleic acid (mRNA) levels were determined by qRT-PCR. RESULTS: Ours results show that resveratrol modulates the studied genes, increasing SIRT1 (p = 0.021), FOXO1 (p = 0.001), and adiponectin (p = 0.025) mRNA expression and decreasing PPARγ1-3 (p = 0.003) mRNA in human visceral adipocytes. CONCLUSIONS: Resveratrol, in vitro and at low concentration, modulates genes that are related to lipid metabolism, possibly preventing metabolic disease in human visceral adipose tissue (VAT).

SIRT1 transcription is decreased in visceral adipose tissue of morbidly obese patients with severe hepatic steatosis.

BACKGROUND: Visceral adipose tissue is known to release greater amounts of adipokines and free fatty acids into the portal vein, being one of the most predictive factors of nonalcoholic fatty liver disease (NAFLD). Our study has the purpose to evaluate sirtuin 1 (SIRT1), adiponectin, Forkhead/winged helix (FOXO1), peroxisome proliferator-activated receptor (PPAR)gamma1-3, and PPARbeta/delta mRNA expression in morbidly obese patients in three different lipid depots: visceral (VAT), subcutaneous (SAT), and retroperitoneal (RAT). Recent studies suggest that SIRT1, a NAD(+)-dependent deacetylase, protects rats from NAFLD. METHODS: We divided the patients in two groups: those with slight or moderate steatosis (hepatic steatosis, HS) and other comprising individuals with severe steatosis associated or not with necroinflammation and fibrosis (severe hepatic steatosis, SHS). The adipose tissue depots were obtained during bariatric surgery. Total RNAs were extracted using TRIzol. The amount of genes of interest was determined by quantitative real-time polymerase chain reaction. RESULTS: When comparing the two groups of patients, a decrease in SIRT1 was observed in VAT of morbidly obese patients in SHS group (p = 0.006). The mRNA expression of the other genes showed no differences in VAT. No difference was found either in SAT or in RAT for all genes in the study. In addition, the homeostasis model assessment for insulin resistance (HOMA-IR) value was higher in SHS group compared to HS (p = 0.006). Also, our results show that the mRNA expression of SIRT1 and the value of HOMA-IR were positively correlated in VAT of SHS patients (r = 0.654; p = 0.048). CONCLUSIONS: Downregulation of SIRT1 mRNA expression in VAT of SHS could be possible impairing mitochondria biogenesis and fatty acid oxidation, promoting severe steatosis in obese patients. Our results provide a possible proof of SIRT1 protective potential in VAT against NAFLD in humans.

Adipose tissue distribution and quantification of PPARbeta/delta and PPARgamma1-3 mRNAs: discordant gene expression in subcutaneous, retroperitoneal and visceral adipose tissue of morbidly obese patients.

BACKGROUND: Adipose tissue (AT) metabolism is altered in obese subjects, and the reestablishment of energy homeostasis requires the identification and regulation of genes with altered patterns. The aim of this study was to compare mRNA expression of PPARbeta/delta and PPARgamma1-3 in morbidly obese and nonobese patients. The expression pattern of these receptors in various abdominal adipose tissues, subcutaneous (SAT), retroperitoneal (RAT) and visceral (VAT), was also evaluated. METHODS: The AT depots were obtained by surgery. Total RNAs were extracted using TRIzol. PPARs reverse transcripts were determined by quantitative polymerase chain reaction (qRT-PCR). RESULTS: The amounts of PPARP/8 mRNA in different depots of morbidly obese AT showed a significant decrease in VAT (P < 0.05). In the non-obese group, the level of PPARbeta/delta was higher in SAT (P < 0.05), but PPARgamma1-3 was not differentially expressed in obese and non-obese depots. When comparing obese and non-obese, the results revealed a decrease in PPARPbeta/delta expression in SAT (P = 0.058) and VAT (P = 0.094) of the morbidly obese. PPARgamma1-3 mRNA expression was increased significantly in SAT (P = 0.022) and decreased in RAT (P = 0.034) in morbidly obese subjects. PPARbeta/delta expression in SAT and VAT correlated negatively with hip size and insulin serum respectively. PPARgamma1-3 expression in RAT correlated negatively with waist and hip circumference and in VAT correlated positively with waist size. CONCLUSIONS: The present study demonstrates that PPARbeta/delta and PPARgamma1-3 mRNAs are quantitatively different in AT of morbidly obese individuals compared to non-obese, and that PPARbeta/delta mRNA levels are characteristic for each AT depot.

Lipídio: fator de risco e prevenção do câncer de mama / Lipid: risk factor and breast cancer prevention

A hipótese de que uma dieta rica em gordura promova o desenvolvimento do câncer de mama na menopausa é fortalecida por estudos caso-controle, que mostram forte associação positiva entre uma dieta rica em lipídios e as taxas de incidência de câncer de mama. Por outro lado, a ingestão dietética de gordura não parece estar relacionada com o risco de câncer de mama em estudos de coorte. Em vista desses achados conflitantes, tem sido difícil propor qualquer recomendação nutricional para a prevenção do câncer de mama. Estudos com animais e observações recentes em humanos, entretanto, têm mostrado evidências de que a dieta rica em ácido graxo linoléico estimula vários estágios no desenvolvimento de câncer mamário. Alguns estudos ainda mostram que o óleo de peixe, constituído de ácidos graxos mega-3, parece prevenir o câncer pela influência sobre a atividade de enzimas e proteínas relacionadas à proliferação celular. Assim, são necessários estudos epidemiológicos que integrem as interações de ácidos graxos específicos com o catabolismo hormonal, fatores nutricionais protetores e de risco relacionados com o câncer de mama. Nesse trabalho, abordaremos os fatores protetores, de risco e as implicações quali e quantitativas dos ácidos graxos da dieta sobre o câncer de mama.

Higher content of trans fatty acids in abdominal visceral fat of morbidly obese individuals undergoing bariatric surgery compared to non-obese subjects.

BACKGROUND: The purpose of this study was to determine the total content of trans fatty acids (TFA) in subcutaneous, retroperitoneal and visceral fat of morbidly obese and non-obese patients submitted to bariatric surgery or plastic and abdominal surgery. METHODS: The adipose tissues were obtained by surgery; lipids were extracted, saponified and esterified. TFA were measured by FTIR-ATR spectroscopy. RESULTS: The TFA average in obese patients was 6.3% for retroperitoneal and 8.7% for visceral fat. For non-obese patients, the figures were 6.9% (subcutaneous) and 9.3% (visceral). There was no difference between the groups. However, the TFA depot in visceral fat was higher than other fatty tissues for morbidly obese (P<0.001) and non-obese (P<0.05) patients. CONCLUSIONS: Our values for TFA content in all adipose tissues analyzed are higher than reported in other countries (3-6%). We showed more TFA in visceral adipose tissue than in other abdominal fat (subcutaneous and retroperitoneal) stores. The visceral adipose tissue level is worrisome because the higher rate of lipolysis in this tissue appears to be an important indicator of metabolic alterations and the levels of TFA found in adipose tissue presumably reflect the higher dietary intake of TFA by Brazilians.

Hepatic stellate cell activation in vitro: cell cycle arrest at G2/M and modification of cell motility.

Hepatic fibrosis is a common response to chronic liver injury and is characterized by increased production of extracellular matrix components, whose major part is produced by hepatic stellate cells activated by inflammatory mediators to proliferate and migrate into the injured regions. GRX cells are a model of hepatic stellate cells characterized as myofibroblasts by morphological and biochemical criteria. We have recently shown that they respond to inflammatory mediators and cytokines present in the concanavalin A-activated spleen cell supernatant (SCS) by quantitative changes in the expression of intermediate filaments. The present study investigated the effects of SCS and TNF-alpha on the GRX cell proliferation and on the organization of the actin cytoskeleton. SCS and TNF-alpha diminished the culture cell density, with an increase of cell [(3)H]thymidine incorporation and of cellular protein content, indicating an arrest in the G2/M phase of the cell cycle, which was reversible 48 h after removal of SCS. This effect was abrogated by dibutiryl-cAMP. Actin cytoskeleton reorganization was observed after 24 h treatment, indicating increased cell motility. Our results suggest that inflammation-dependent activation of stellate cells occurs in ordered interaction and coordination of proinflammatory agents. The increase of cAMP levels activates the conversion of lipocytes into myofibroblasts and increases the number of cells that can participate in repair. Since cAMP retains cells in the G1 phase, cytokines of the TNF-alpha group are required for cell proliferation inducing the entry into the S phase. The progression through the G2/M checkpoint is mediated again by increased cAMP levels.