Maturation and aging of collagen - some functional aspects.
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Age Factors↗
Biomedical subjects
H Oxlund
Publications and source records attributed to H Oxlund.
Penicillamine in rheumatoid arthritis. Connective tissue changes and alterations in serum copper and phase reactants in relation to clinical improvement.
Thirteen patients, aged 27 to 70 years, with definite or classical rheumatoid arthritis were treated with penicillamine for six months. Skin biopsies and blood samples were compared with a clinical evaluation before and after therapy. The analyses of the skin included determinations of total collagen, thermal reaction of collagen, salt soluble collagen, in vitro uptake of 14C-proline and synthesis of 14C-hydroxyproline, as well as determinations of nucleic acids and proteoglycans. Serum concentrations of acute phase reactants, immunoglobulins, complement C3 and C4, rheumatoid factor, and iron, copper, and zinc were also determined. A positive correlation was found between clinical improvement and a fall in the number of granulocytes, a decrease in the concentration of acute phase reactants and serum copper, and an increase in salt soluble collagen of the skin. The total skin collagen decreased during treatment with penicillamine. The changes in skin collagen may reflect a generalized effect of penicillamine on collagen. These alterations may be part of an anti-inflammatory action of penicillamine.
Adult↗
Growth hormone increases the biomechanical strength and collagen deposition rate during the early phase of skin wound healing.
The effects of biosynthetic human growth hormone on the biomechanical properties and collagen deposition rate of wound healing were investigated in rat skin incisional wounds after 4 days of healing. Biosynthetic human growth hormone induced a pronounced, < or =94%, and dose-dependent increase in the mechanical strength of wounds in the dose range of 0.125 to 2 mg/kg/day. A new method for in vivo studies of the collagen deposition rate in granulation tissue of the wound cleft was applied. The production of (3)H-hydroxy-l-proline was measured by injecting (3)H-proline intravenously into the rats with a large flooding dose of unlabeled proline which reduces reutilization of (3)H-proline and reduces the influence of de novo synthesis of proline. Extractable collagens, which are not bound in the wound tissue and therefore do not contribute mechanical strength to it, were removed from the samples. Labeled and unlabeled proline were determined simultaneously by reverse-phase high-performance liquid chromatography with ultraviolet detection and flow scintillation counting of these amino acids. At day 4 the collagen deposition rate in the incisional wound zone, 0.4 mm wide containing the wound cleft, was 1.8% per hour of the collagen present in the wound zone. The collagen deposition rate was increased by 149% by biosynthetic human growth hormone 2 mg/kg/day compared with the control group. This result indicates that the increased biomechanical strength of the skin incisional wounds of the groups treated with biosynthetic human growth hormone was produced by an increased deposition of collagen in the wound cleft.
Journal Article↗
Influence of biosynthetic human growth hormone on the biomechanical strength development in skin incisional wounds of diabetic rats.
The influence of biosynthetic human growth hormone (b-hGH) on the mechanical strength development of skin incisional wounds in diabetic rats has been investigated after 4, 7 and 21 days of healing. Diabetes caused decreased mechanical strength of the wounds. After 21 days of healing, the diabetic animals treated with b-hGH from 7 days before wound infliction had an increased maximum load (14%) compared with the untreated diabetic animals. After 4 and 7 days of healing, no differences in the biomechanical strength of diabetic wounds with and without b-hGH treatment were found. The diabetic animals receiving b-hGH showed a significant increase in body weight compared with the untreated diabetic animals. In the diabetic animals, the blood glucose concentration was increased by treatment with b-hGH. In conclusion, treatment with b-hGH from 7 days before operation can counteract the reduced mechanical strength of skin wounds in diabetic rats on day 21.
Animals↗
The influence of experimental diabetes and insulin treatments on the biochemical properties of rat skin incisional wounds.
The mechanical properties (tensile strength, extensibility, relative failure energy) of skin incisional wounds were analyzed after 7, 10 and 20 days of healing in normal rats, diabetic rats treated with insulin from the day of wound infliction and diabetic rats treated with insulin from the 5th preoperative day. Untreated diabetes resulted in a reduction of the failure energy of skin wounds during the 20 days of wound healing. After 7 days of wound healing, insulin treatment starting on the day of wound infliction or on the 5th preoperative day did not eliminate this reduction in failure energy of wounds induced by diabetes. However, a positive correlation was found between the duration of the insulin treatment and the failure energy of the wounds. After 10 and 20 days of wound healing, the mechanical parameters of wounds from diabetic rats treated with insulin from the day of wound infliction or from the 5th preoperative day did not differ from those of the control wounds. The experiment demonstrates that insulin treatment is essential for adequate wound healing in diabetes. Insulin treatment from the day of wound infliction or from the 5th preoperative day is not, however, sufficient to prevent the inhibitory effects of diabetes in the early phase of wound healing.
Animals↗