ABSTRACT
The aim of the study was to investigate the effect of two various atherogenic stimuli (vasopressin-induced hypertension or hypercholesterolemia) on the collagen and glycosaminoglycan (GAG) content in the internal or external part of both thoracic and abdominal aorta, which are differently susceptible to atherosclerosis. Experimental rabbits were divided into four groups: controls, animals injected with physiological saline or vasopressin at the dose of 1 IU/kg from the 1 st to the 25 th day of experiment, respectively. The animals from group 4 were maintained on food, containing 0.25% cholesterol. Only in the vasopressin-treated group, the systolic blood pressure was elevated from 110 mmHg at the beginning, to 166 mmHg at the end of the study. After 14 weeks the aorta was dissected into internal and external parts. GAG fractions were separated and estimated as uronic acids. Collagen was evaluated as the hydroxyproline content in the tissue. Augmented total GAG and heparan sulphate (HS) level, plus no changes in the collagen content were seen in the internal part of the thoracic aorta in rabbits with hypercholesterolemia or hypertension. In the hypertensive animals, the changes were extended to the external part of the aorta and, additionally, comprised the elevation of the chondroitin-4 sulphate (C-4S) content. The two atherogenic stimuli increased the collagen level with no elevation of the GAG content in the abdominal aorta. A convergent effect of the injury, caused by hypertension or hypercholesterolemia on the collagen, total GAG and HS content was shown in the respective parts of the rabbit aortas. The common GAG, increased in the thoracic aorta, stand for the HS, in both hypertensive and hypercholesterolemic rabbits. As the sensitivity to atherosclerosis development in different segments of the aorta varies, they express various responses of the connective tissue matrix to injuries, caused by hypertension or hypercholesterolemia.
Subject(s)
Aorta, Abdominal/metabolism , Aorta, Thoracic/metabolism , Cholesterol/blood , Collagen/metabolism , Glycosaminoglycans/metabolism , Hypercholesterolemia/metabolism , Hypertension/metabolism , Animals , Connective Tissue/metabolism , Hypercholesterolemia/chemically induced , Hypertension/chemically induced , Male , Rabbits , Vasoconstrictor Agents , VasopressinsABSTRACT
Dynamics and glucose uptake in the human fibroblasts cultures were investigated for 14 days. Fibroblasts were taken from 16 patients with diabetes mellitus type 2 and 8 patients adjusted with age but with no history of diabetes mellitus. It was found that diabetic fibroblasts grew much slower than controls and reached the stationary phase later. Glucose uptake in both groups of fibroblasts--measured as the diminishment of glucose levels in the medium every two days--did not differ markedly in the phase of the rapid proliferation whereas was significantly higher in the stationary phase in the cultures of diabetic fibroblasts in comparison with the controls. It may thus assumed that diabetic fibroblasts reveal abnormal glucose metabolism in addition to reported intracellular disorders in protein, nucleic acids, lipids, collagen, and glycosaminoglycans synthesis.
