Tagging single nucleotide polymorphisms in the PPAR-γ and RXR-α gene and type 2 diabetes risk:a case-control study of a Chinese Han population

Peroxisome proliferator-activated receptor （PPAR-γ）,which is mainly involved in adipocyte differentiation, has been suggested to play an important role in the pathogenesis of insulin resistance and atherosclerosis. We investigated the frequencies of two common tagging polymorphisms of the PPAR-γ gene and two of PPAR-α with minor allele frequency （MAF）≥ 0.05 in the Chinese Han population and analyzed the correlation between the different genotypes and the risk of type 2 diabetes mellitus （T2DM）. TaqMan assay was performed to test the genotypes in T2DM patients （n = 1,105） and normal controls （n = 1,107）. Serum adiponectin concentration was measured by ELISA kit. The variant genotypes rs17817276GG, rs3856806CT and rs3856806CT/TT of PPAR-γ were associated with T2DM, P = 0.023,0.037 and 0.018, respectively. Furthermore, the prevalence of haplotype GT in PPAR-γ was less frequent in the case subjects （0.3%） than in the controls （1.9%） [P 0.001,OR（95%CI）=0.13 （0.06-0.31）]. Patients with genotype TT of rs3856806 had a higher serum level of adiponectin than those with the genotype CC and CT （P = 0.031 and 0.038, respectively）. There was no statistically significant difference between patients and controls in genotype distribution of rs6537944 and rs1045570 of the RXR-α gene. The present study suggests that the variant genotypes in the PPAR-γ gene could decrease the risk for the development of T2DM in the Chinese Han population.

Application of the back-error propagation artificial neural network(BPANN) on genetic variants in the PPAR-γ and RXR-α gene and risk of metabolic syndrome in a Chinese Han population

This study was aimed to explore the associations between the combined effects of several polymorphisms in the PPAR-γ and RXR-α gene and environmental factors with the risk of metabolic syndrome by back-error propaga- tion artificial neural network （BPANN）. We established the model based on data gathered from metabolic syndrome patients （n = 1012） and normal controls （n = 1069） by BPANN. Mean impact value （MIV） for each input variable was calculated and the sequence of factors was sorted according to their absolute MIVs. Generalized multifactor dimensionality reduction （GMDR） confirmed a joint effect of PPAR-9＂ and RXR-a based on the results from BPANN. By BPANN analysis, the sequences according to the importance of metabolic syndrome risk fac- tors were in the order of body mass index （BMI）, serum adiponectin, rs4240711, gender, rs4842194, family history of type 2 diabetes, rs2920502, physical activity, alcohol drinking, rs3856806, family history of hypertension, rs1045570, rs6537944, age, rs17817276, family history of hyperlipidemia, smoking, rs1801282 and rs3132291. However, no polymorphism was statistically significant in multiple logistic regression analysis. After controlling for environmental factors, A1, A2, B1 and B2 （rs4240711, rs4842194, rs2920502 and rs3856806） models were the best models （cross-validation consistency 10/10, P = 0.0107） with the GMDR method. In conclusion, the interaction of the PPAR-γ and RXR-α gene could play a role in susceptibility to metabolic syndrome. A more realistic model is obtained by using BPANN to screen out determinants of diseases of multiple etiologies like metabolic syndrome.

Pioglitazone attenuates the severity of sodium taurocholate-induced severe acute pancreatitis

AIM： To determine the effect of pioglitazone, a specific peroxisome proliferator-activated receptor-γ, （PPARγ） ligand, on development of severe acute pancreatitis （SAP） and expression of nuclear factor-kappa B （NF-κB） and intercellular adhesion molecule-1 （ICAM-1） in the pancreas. METHODS： Male Sprague-Dawley （SD） rats （160-200 g） were randomly allocated into three groups （n = 18 in each group）： severe acute pancreatitis group, pioglitazone group, sham group. SAP was induced by retrograde infusion of 1 mL/kg body weight 5% sodium taurocholate （STC） into the biliopancreatic duct of male SD rats. Pioglitazone was injected intraperitoneally two hours piror to STC infusion. Blood and ascites were obtained for detecting amylase and ascitic capacity. Pancreatic wet/dry weight ratio, expression of NF-κB and ICAM-1 in pancreatic tissues were detected by immunohistochemical staining. Pancreatic tissue samples were stained with hematoxylin and eosin （HE） for routine optic microscopy. RESULTS： Sham group displayed normal pancreatic structure. SAP group showed diffuse hemorrhage, necrosis and severe edema in focal areas of pancreas. There was obvious adipo-saponification in abdominal cavity. Characteristics such as pancreatic hemorrhage, necrosis, severe edema and adipo-saponification were found in pioglitazone group, but the levels of those injuries were lower in pioglitazone group than those in SAP group. The wet/dry pancreatic weight ratio, ascetic capacity, serum and ascitic activities of anylase in the SAP group were significantly higher than those in the sham group and pioglitazone group respectively （6969.50 ± 1368.99 vs 2104.67 ± 377.16, 3.99 ± 1.22 vs 2.48 ± 0.74, P 〈 0.01 or P 〈 0.05）. According to Kusske criteria, the pancreatic histologic score showed that interstitial edema, inflammatory infiltration, parenchyma necrosis and parenchyma hommorrhage in SAP group significantly differed from those in the sham group and pioglitazone group （7.17 ± 1.83 vs 0.50 ± 0.55, 7.67 ± 0.82 vs 6.83 ± 0.75, P 〈 0.01, P 〈 0.05. The expression of NF-κB and ICAM-1 in sham group was lower than that in SAP group and pioglitazone group （0.50 ± 0.55 vs 33 ± 1.21, P 〈 0.01）. There was a significant difference in the expression of NF-κB and ICAM-1 between SAP group and pioglitazone group （7.50 ±1.05 vs 11.33 ± 1.75, 0.80 ± 0.53 vs 1.36 ± 0.54, P 〈 0.01 or P 〈 0.05） at 12 h after the induction of pancreatitis. CONCLUSION： Pioglitazone attenuates the severity of SAP. The beneficial effect of pioglitazone is multifactorial due to its anti-inflammatory activities, most likely through the inhibition of ICAM-1 expression and NF-κB activation. Specific ligands of PPARy may represent the novel and effective means of clinical therapy for SAP.

Rhinacanthus nasutus leaf improves metabolic abnormalities in high-fat diet-induced obese mice

Objective:To investigate the effect of Rhinacanthus nasutus(R.nasutus) leaf extract on impaired glucose and lipid metabolism in obese ICR mice.Methods:Obesity was induced in the male ICR mice by feeding them a high-fat diet(60 kcal%fat) for 12 weeks.After the first six weeks of the diet,the obese mice were administered with the water extract of R.nasutus leaves at 250 and 500 mg/kg per day for the next six weeks.Subsequently,the blood glucose,lipid profiles,insulin,leptin,and adiponectin levels were measured.The liver and adipose tissues were excised for histopathological examination and protein expression study.Results:After six weeks of the treatment,R.nasutus extract(at 250 and 500 mg/kg per day) was found to reduce the elevated blood glucose level,improve the insulin sensitivity,decrease the serum leptin,and increase the serum adiponectin levels.The obese mice treated with R.nasutus were found to have a reduction in the increased lipid concentrations in their serum and liver tissues.Moreover,treatment with R.nasutus reduced the fat accumulation in the liver and the large adipocyte size in the fat tissues.Interestingly,the administration with R.nasutus extract was marked by an increase in the hepatic peroxisome proliferators-activated receptor alpha,fat cell adiponectin,and glucose transporter 4 proteins.Conclusions:To the best of our knowledge,the present study is the first report on the impact of R.nasutus extract in improving the impaired glucose and lipid metabolism in high-fat diet-induced obesity in mice via stimulating the insulin sensitivity in the liver and adipose tissues.