α-Smooth Muscle Actin and ACTA2 Gene Expressions in Vasculopathies

ABSTRACT α-smooth muscle actin, encoded by ACTA2 gene, is an isoform of the vascular smooth muscle actins, typically expressed in the vascular smooth muscle cells contributing to vascular motility and contraction. ACTA2 gene mutations cause a diversity of diffuse vasculopathies such as thoracic aortic aneurysms and dissections as well as occlusive vascular diseases, including premature coronary artery disease and ischemic stroke. Dynamics of differentiation-specific α-smooth muscle actin in arterial smooth muscle cells and proliferation of the proteins have been well described. Although a variety of research works have been undertaken in terms of modifications of α-smooth muscle actin and mutations of ACTA2 gene and myosin, the underlying mechanisms towards the pathological processes by way of gene mutations are yet to be clarified. The purpose of the present article is to describe the phenotypes of α-smooth muscle actin and implications of ACTA2 mutations in vasculopathies in order to enhance the understanding of potential mechanisms of aortic and coronary disorders.

Effect of increased levels of adiponectin by administration of the adenovector rAAV2/1-Acrp30 on glucose, lipid metabolism and ultrastructure of the aorta in Goto–Kakizaki rats with arteriosclerosis.

Background. We used recombinant adeno-associated virus vector of adiponectin (AAV2/1-Acrp30) to study the effects of increased levels of adioponectin (by the administration of rAAV2/1-Acrp30) on arteriosclerosis, glucose and lipid metabolism in Goto–Kakizaki (GK) rats with arteriosclerosis. Methods. Thirty GK rats with arteriosclerosis were divided into 3 equal groups: control group 1, control group 2 and the rAAV2/1-Acrp30-administered group. Saline, virus vector or rAAV2/1-Acrp30 (1012 ng/ml) vector genomes administered to the rats in the corresponding group by intramuscular injection to the posterior limb by single administration, respectively. After 8 weeks, fasting blood glucose, 2-hour postprandial blood glucose, glycosylated haemoglobin, serum insulin, serum total cholesterol, triglycerides, high-density lipoprotein and low-density lipoprotein were measured in each group, and the ultrastructure of the aorta was seen by light and electron microscopy. Results. Compared with control groups 1 and 2, in the rAAV2/1-Acrp30 group, there was a decrease in urine volume, fasting blood glucose, 2-hour postprandial blood glucose, glycosylated haemoglobin, serum total cholesterol, triglycerides and low-density lipoprotein, and an increase in body weight and high-density lipoprotein (p<0.05), while the level of serum insulin was not changed (p>0.05). Ultrastructure studies of the aorta showed that aortosclerosis in the rAAV2/1-Acrp30-administered group was less, and fewer lipid droplet vacuoles were seen in the vascular endothelial cytoplasm. Also various cell organelles and internal elastic lamina were seen, and there was no formation of lipid droplet and foam cells in the cytoplasm of the media of the smooth muscle. Conclusion. Adiponectin could improve blood glucose and lipid parameters and decrease atherosclerosis in the aorta of GK rats.

Efeitos da atorvastatina, fluvastatina, pravastatina e simvastatina sobre a função endotelial, a peroxidação lipídica e a aterosclerose aórtica em coelhos hipercolesterolêmicos / Effects of atorvastatin, fluvastatin, pravastatin, and simvastatin on endothelial function, lipid peroxidation, and aortic atherosclerosis in hypercholesterolemic rabbits

OBJETIVO: Comparar os efeitos da atorvastatina, fluvastatina, pravastatina e simvastatina sobre a função endotelial, a aterosclerose aórtica e o teor de malonodialdeído (MDA) nas LDL nativas, oxidadas e na parede arterial de coelhos hipercolesterolêmicos, depois que as doses destas estatinas foram ajustadas para reduzir o colesterol total plasmático a valores similares. MÉTODOS: Coelhos machos, foram separados em grupos de 10 animais (n=10), chamados hipercolesterolêmico (controle), atorvastatina, fluvastatina, pravastatina e normal. A exceção do grupo normal, os animais foram alimentados com ração padrão acrescida de colesterol a 0,5 por cento e óleo de coco a 2 por cento durante 45 dias. As drogas foram administradas a partir do 15° dia do início do experimento e no 30° dia, as doses foram ajustadas, através do controle do colesterol plasmático, para obter valores semelhantes em cada grupo. Ao final do experimento foi dosado o colesterol plasmático e as lipoproteinas e retirado um segmento de aorta torácica para estudo da função endotelial, da peroxidação lipídica e exame histológico para medida da aterosclerose aórtica. RESULTADOS: As estatinas reduziram significantemente o colesterol total plasmático, as LDL-colesterol e a aterosclerose aórtica. O teor de MDA também foi significantemente reduzido nas LDL nativas e oxidadas, assim como na parede arterial. O relaxamento-dependente do endotélio foi significantemente maior no grupo tratado em comparação ao hipercolesterolêmico. CONCLUSÃO: As estatinas, em doses ajustadas, tiveram efeito significante e similar em reduzir a peroxidação lipídica nas LDL e na parede arterial, na regressão da aterosclerose aórtica e na reversão da disfunção endotelial.