hydroxylysine and Hypertrophy

It is demonstrated that dietary habits play a role in cardiovascular diseases. In stroke-prone spontaneously hypertensive rats (SHRsp), concomitant salt loading and a Japanese-style diet greatly accelerate hypertension and the appearance of cerebrovascular lesions by directly damaging arterial vessels. A number of studies have characterised medium and small vessel lesions in SHRsp, but little attention has been paid to the changes in the wall structure of large arteries induced by exposure to a salt-enriched diet. The aim of this study was to investigate the effects of a Japanese-style diet and salt loading on the thoracic aorta.. Two-month-old SHRsp were kept on a Japanese-style diet with 1% sodium chloride solution replacing tap water. Two months later, they were sacrificed and compared with age-matched or two-month-old control SHRsp kept on a standard diet and tap water in terms of the histomorphometry, ultrastructure and biochemical composition of the thoracic aorta. The vessel was consistently thicker in the four-month-old SHRsp (+20%, p < 0.05 vs two-month-old rats) regardless of diet. The salt-loaded SHRsp showed a significant reduction in elastic fibre density (-20%, p < 0.05 vs two-month-old rats) and an increase in the other matrix components (%), whereas the four-month-old controls showed preserved elastic fibres and a significant increase in the other matrix components (+65%, p < 0.05 vs two-month-old rats). There was a considerable increase in the amounts of 4-OH-proline (+147%), 5-OH-lysine (+174%) and desmosines (+360%) in the four-month-old controls vs their two-month-old counterparts (p < 0.01), but not in the salt-loaded animals. Ultrastructural analysis revealed clear damage and accelerated aging in the thoracic aorta of the salt-loaded SHRsp.. Salt loading and a Japanese-style diet destabilize thoracic aorta architecture in SHRsp after two months of treatment.

Topics: Aging; Animals; Aorta, Thoracic; Blood Pressure; Collagen; Desmosine; Diet; Elastin; Endothelium, Vascular; Hydroxylysine; Hydroxyproline; Hypertension; Hypertrophy; Isodesmosine; Japan; Male; Microscopy, Electron; Muscle, Smooth, Vascular; Rats; Rats, Inbred SHR; Sodium Chloride, Dietary; Stroke; Tunica Intima; Tunica Media

Hypertrophic cartilage from the tibiotarsus of Day 20 chick embryonic tibiae was found to contain an unusually high concentration of lysylpyridinoline (LP), a nonreducible collagen cross-link normally found only in bone and dentin but not in cartilage. Since type X collagen is abundant in this cartilage, research was conducted to see if type X was the primary source of LP. The 45-kDa pepsin-resistant form of type X was purified by immunoaffinity chromatography. It contained a high concentration of the LP cross-link while type II contained primarily hydroxylysylpyridinoline (HP), the predominant cross-link in cartilage. This, to our knowledge is the first time that type X has been shown directly to form nonreducible cross-links and that a collagen other than type I has a high level of LP. Also, it is interesting that the HP and LP cross-links are found in a collagen that is degraded so rapidly. Possible explanations for these findings are discussed.

Topics: Amino Acids; Animals; Cartilage; Chick Embryo; Collagen; Cross-Linking Reagents; Electrophoresis, Polyacrylamide Gel; Hydroxylysine; Hypertrophy; Molecular Weight; Pepsin A; Tibia

The collagen produced in response to an injury of human skin is initially stabilized by a cross-link derived from hydroxyallysine, and characteristic of embryonic skin. In normal healing there is a change over with time to the cross-link derived from allysine, which is typical of young skin collagen. In contrast, hypertrophic scars fail to follow the time-related changes of normal skin, but retain the characteristics of embryonic collagen, indicating a continued rapid turnover of the collagen. This is further supported by the high proportion of the embryonic Type III collagen present in hypertrophic scars.

Topics: Adolescent; Adult; Amino Acids; Child; Cicatrix; Collagen; Elastin; Humans; Hydroxylysine; Hypertrophy; Macromolecular Substances; Middle Aged; Protein Binding; Skin; Solubility; Time Factors; Water