RESUMEN
BACKGROUND: Integrin-linked kinase (ILK) is a protein that plays an important role in extracellular matrix-mediated signalling. Recent studies implicated ILK dysregulation in the development of diabetic nephropathy. However, little is known about the significance of ILK up-regulation in response to high glucose in mesangial cells. METHODS: The ILK messenger (m)RNA and protein expression in human mesangial cells were analysed with quantitative real-time polymerase chain reaction (PCR) and western blotting after exposure to either 100, 200, or 500 mg/dl glucose, or 100 mg/dl glucose + 400 mg/dl mannitol. Activation of protein Kinase B (PKB)/Akt was also determined by western blot analysis. Cells were transfected with ILK siRNA to determine the effects of ILK knockdown on PKB/Akt activation and cell death following treatment with high glucose or mannitol. RESULTS: High concentrations of glucose or mannitol for three days significantly up-regulated ILK mRNA and protein expression (P < 0.05 vs 100 mg/dl glucose). In contrast, ILK expression in cells exposed to the same conditions for seven days was unaffected. The time course of PKB/Akt phosphorylation was similar to that of ILK protein expression. The siRNA-mediated down-regulation of ILK expression inhibited the elevation of PKB/Akt phosphorylation induced by high glucose treatment. Furthermore, the inhibition of ILK expression promoted high glucose- or mannitol-induced apoptosis. CONCLUSION: The ILK may act as a pro-survival factor and play a role in protecting mesangial cells from hyperglycaemic osmotic stress.
Asunto(s)
Nefropatías Diabéticas/patología , Glucosa/metabolismo , Células Mesangiales/citología , Células Mesangiales/metabolismo , Proteínas Serina-Treonina Quinasas/fisiología , Regulación hacia Arriba , Apoptosis , Muerte Celular , Supervivencia Celular , Células Cultivadas , Nefropatías Diabéticas/metabolismo , Humanos , Manitol/metabolismo , Ósmosis , Proteínas Serina-Treonina Quinasas/metabolismo , ARN/metabolismo , ARN Mensajero/metabolismo , ARN Interferente Pequeño/metabolismoRESUMEN
Resistin is a novel cysteine-rich protein that plays a role in the development of insulin resistance and atherosclerosis. HMG-CoA reductase inhibitors (statins) possess anti-inflammatory properties that are independent of their lipid-lowering action. The aims of this study were to investigate the effect of atorvastatin on expression of resistin in vitro and to determine the effect of 6 months of treatment with atorvastatin on serum levels of resistin in patients with type 2 diabetes. 3T3-L1 adipocytes and human monocytes/macrophages and preadipocytes were incubated with 1 and 10 micromol/l atorvastatin for 24 and 48 h, followed by measurement of resistin mRNA by the quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Serum resistin concentration in the patients with type 2 diabetes was measured at baseline and after 6 months of atorvastatin treatment (10 mg/day). qRT-PCR analysis revealed that atorvastatin decreased resistin mRNA expression in a dose- and time-dependent manner. Serum resistin concentration tended to decrease after 6 months of atorvastatin treatment, although this decrease did not reach statistical significance. In conclusion, the findings of our in vitro study contribute to the growing volume of evidence on the anti-inflammatory and anti-atherosclerotic effects of statins, and led us to suggest that statins may control inflammatory responses by inhibiting expression of resistin mRNA. It is necessary to confirm the findings of our in vitro study by an appropriately designed large-scale clinical study.
Asunto(s)
Diabetes Mellitus Tipo 2/sangre , Ácidos Heptanoicos/farmacología , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Pirroles/farmacología , Resistina/metabolismo , Células 3T3-L1 , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Animales , Atorvastatina , Células Cultivadas , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Masculino , Ratones , Persona de Mediana Edad , Monocitos/efectos de los fármacos , Monocitos/metabolismo , ARN Mensajero/metabolismo , Resistina/sangre , Resistina/genéticaRESUMEN
We retrospectively investigated the effects of adding glimepiride in patients with type 2 diabetes showing suboptimal control by insulin therapy. Of 63 patients with poorly controlled insulin-treated type 2 diabetes (baseline HbA1c, 8.4 +/- 0.6%), 32 were treated with insulin alone and 31 were given glimepiride in addition to insulin. HbA1c values, daily insulin dose, body weight, blood pressure, plasma lipid concentrations, and the number of hypoglycemic events were recorded at weeks 0, 12, 24, 36, 48, 60, and 72. HbA1c decreased by 1.1%, from 8.5 +/- 0.6% to 7.4 +/- 0.8% (P<0.0001) in patients treated with insulin plus glimepiride at 12 weeks, and improved glycemic control continued throughout the study. Required insulin dose was reduced significantly in patients treated with insulin plus glimepiride (from 29.4 +/- 14.5 to 22.3 +/- 12.1 units/day, P = 0.0187). Body weight increased significantly in patients treated with insulin plus glimepiride (from 57.0 +/- 8.7 to 59.5 +/- 9.2 kg, P = 0.0232). Adding glimepiride showed little effect on blood pressure, plasma total cholesterol, triglyceride, or HDL-cholesterol. Serum C peptide concentrations increased significantly in patients treated with insulin plus glimepiride (from 1.01 +/- 0.71 to 1.28 +/- 0.65 ng/ml, P = 0.0367). The number of hypoglycemic events did not differ between groups. Adding glimepiride to insulin therapy resulted in sustained improvement of glycemic control in patients with poorly controlled type 2 diabetes.