Fibronectin, glycosaminoglycans and vessel wall thickness in diabetic micro-angiopathy before and after control of diabetic state

ABSTRACT

This work was conducted to evaluate the role of fibronectin [FN] and glycosaminoglycans [GAG] in diabetic vascular complications and to study the effect of different modalities of treatment of diabetes on microangiopathy. Plasma, FN, 24-hours urinary GAG, and capillary and arteriolar wall thickness in skeletal muscle biopsy specimens were measured in 15 control subjects and 45 diabetic patients classified according to their line of treatment into insulin group, glipizide group and gliclazide group. The patients were further subdivided into diabetics with and diabetics without microvasular complications [retinopathy and or nephropathy]. At the beginning of the study, the mean values of plasma FN, urinary GAG and percentage wall thickness of muscle capillaries and arterioles for each of the patient groups were significantly higher than those for control group [P<0.01 for all parameters in all groups]. By the end of one year therapy with control of hyperglycemia, plasma FN level decreased significantly in non complicated orally treated patients [P<0.01 in glipizide subgroup and P<0.05 in gliclazide subgroup], while urinary GAG had decreased significantly in all non complicated diabetics [P<0.05]. We observed, also a significant decrease in muscle capillary and arteriolar wall thickness in both non complicated, insulin [P<0.05] and glipizide [P<0.01] treated subgroups. Finally, a significant positive correlation was observed between both plasma FN and percentage wall thickness of muscle capillaries and arterioles in all patient groups at the beginning of the study and in orally treated groups one year after therapy. We concluded that thickening of skeletal muscle capillary and arteriolar wall and elevated plasma FN levels could be used as early indicators of diabetic microangiopathy. Also raised levels of FN and GAG may have a role in the pathogenesis of diabetic microangiopathy. Finally we found in this study that glipizide had better effect concerning diabetic microangiopathy than insulin and gliclazide