RESUMO
Blood viscosity is an important cardiovascular risk factor that might be related to diabetes complications. Hyperinsulinemia has been suggested as "the most important candidate" to characterise diabetes as a risk factor for cardiovascular disease. There is no evidence of the beneficial effect of insulin on type 2 diabetes erythrocytes in patients without cardiovascular disease, whereas the opposite is observed in those with cardiovascular disease. In the present study we analysed the in vitro effect of different doses of insulin on red blood cell rheological aspects in an obesity model. Previous studies carried out in beta strain rats had shown that this strain possess insulin blood levels higher than the ones observed in alpha strain (eumetabolic), as well as blood hyperviscosity and erythrocyte deformability decrease. Our results points out that in vitro insulin produced an increase in erythrocyte aggregability, although it did not modified either their osmotic fragility or erythrocyte deformability estimated by viscometry, even against decreased viscosity of treated erythrocytes submitted to increased shear rate.
Assuntos
Eritrócitos/efeitos dos fármacos , Hemorreologia , Insulina/farmacologia , Animais , Viscosidade Sanguínea , Agregação Eritrocítica , Deformação Eritrocítica , Hiperinsulinismo/sangue , Obesidade/sangue , Ratos , Ratos EndogâmicosRESUMO
Few studies have been performed in humans to investigate the effect of caloric restriction and consequent biomass reduction on hemorheologic parameters and their results are not concurrent. In a previous paper we analyzed the rheological behavior of the blood in the IIMb/Fmbeta inbred obese and hypertriglyceridemic strain in relation to its eumetabolic control [G.N. Hernández, C. Dabin, M.C. Gayol and M.L. Rasia, Hemorheological variables in a rat model of hypertriglyceridemic obesity and diabetes, Veterinary Res. Commun. 26 (2002), 625-635]. In this obese line it was shown a higher blood and plasma viscosity and an impaired red cell deformability compared to the eumetabolic one. The increased plasma viscosity was significantly and positively associated with fibrinogenaemia and lipidaemia and the impaired erythrocyte deformability with cholesterolemia and hypertriglyceridaemia. The present study has been designed to find out the effect of a 30% food restriction on several biochemical and hemorheological parameters of these obese rats. Restriction resulted in a mean body weight 45% lower than ad libitum controls, preventing obesity and hypertriglyceridemia with minimal effect on glucose metabolism. Regarding hemorheological parameters, caloric restriction led to a decrease in blood viscosity, due to the reduction in erythrocyte concentration, but not because of any improvement in erythrocyte deformability.