dihydrotachysterol and Aortic-Diseases

Topics: Animals; Aorta; Aortic Diseases; Calcinosis; Dihydrotachysterol; Edetic Acid; Glucagon; Rabbits

Aortic medial calcification was investigated in rats in which the progeria-like syndrome (PLS) was evoked by administering dihydrotachysterol. In 35 experimental rats and 15 controls, calcification was studied morphologically by light and electron microscopy, and by enzyme histochemistry. Body weight, food intake and serum calcium levels were also determined. Calcification occurred along and on the elastic lamellae in association with the accumulation of ground substance. In the smooth-muscle cells surrounding the calcified foci, the activities of various lysosomal enzymes increased concomitantly with a tendency toward transformation of smooth-muscle cells to a modified form. From these observations, the role of ground-substance formation by smooth-muscle cells is postulated, and participation in the catabolism of ground substance by the lysosomal enzymes of these cells is suggested. It appears the increased activity of adenosine monophosphatase should be linked to the calcification. The etiology of weight loss, skin manifestations and aortic calcification in PLS rats seems to be different from that in human progeric diseases. Therefore, the PLS rat should not be readily accepted as an animal model for the study of progeric diseases.

Topics: Acid Phosphatase; Adenosine Triphosphatases; Animals; Aorta; Aortic Diseases; Apyrase; Body Weight; Calcinosis; Calcium; Dihydrotachysterol; Female; Glucuronidase; Hexosaminidases; Histocytochemistry; Phosphoric Monoester Hydrolases; Rats; Werner Syndrome

Early dihydrotachysterol-induced calcification of the rat aorta occurs in elastic lamellae. The first deposition of inorganic substance leads to the formation of very thin filament-like structures of low electron density. The characteristic shape of these structures suggests that they could correspond to calcified filamentous components of the elastic tissue. When calcification spreads from the calcified elastic lamellae into the adjacent tissue, the inorganic substance is initially collected in roundish structures, probably of cellular origin, and is successively laid down in the entire matrix of the aortic wall, including collagen fibrils. All the calcified areas contain glycoproteins and acid proteoglycans. A cartilage-like tissue often develops near calcified areas. Its fine structure is very similar to that of the normal hyaline cartilage. It can be calcified, but usually the inorganic substance is not crystalline as it is in normal cartilage. It seems to consist of very small, linearly aggregated inorganic granules which form irregular structures. These seem to develop in close relationship with the fibrillar, probably collagenic, network of the matrix. No ultrastructural findings have been obtained for explaining cartilage induction near calcified areas of the aortic wall. It is possible that cartilage differentiation is regulated by diffusible substances which cannot be recognized under the electron microscope.

Topics: Animals; Aorta, Thoracic; Aortic Diseases; Calcinosis; Dihydrotachysterol; Elastic Tissue; Glycoproteins; Microscopy, Electron; Proteoglycans; Rats; Staining and Labeling

Topics: Animals; Aorta; Aortic Diseases; Calcinosis; Calcium; Dihydrotachysterol; Histocytochemistry; Rats

Topics: Animals; Aortic Diseases; Calcinosis; Dihydrotachysterol; Estradiol; Kidney Diseases; Organophosphonates; Phloretin; Phosphates; Phosphoric Monoester Hydrolases; Rats; Skin Diseases

Topics: Animals; Aortic Diseases; Arteriosclerosis; Calcinosis; Dihydrotachysterol; Heart Diseases; Lung Diseases; Rats

Topics: Aging; Animals; Animals, Newborn; Aortic Diseases; Arteriosclerosis; Blood; Body Weight; Calcinosis; Coronary Disease; Dihydrotachysterol; Female; Hypercalcemia; In Vitro Techniques; Kidney Diseases; Lactation; Pregnancy; Pregnancy, Animal; Rats

Topics: Adipose Tissue; Alopecia; Aortic Diseases; Atrophy; Calcinosis; Cockayne Syndrome; Coronary Disease; Dihydrotachysterol; Emaciation; Kidney Diseases; Kyphosis; Muscular Atrophy; Osteosclerosis; Pathology; Pharmacology; Progeria; Rats; Research; Sex; Sex Characteristics; Skin Diseases; Tooth Abnormalities; Toxicology