[Comparative characteristics of oxyproline excretion in urine in children with post-burn hypertrophic and keloid...

Catabolism of collagen was studied in 25 children with keloid and hypertrophic scars by means of evaluation of total and polypeptide-bound hydroxyproline excreted with urine. Formation of postburn pathological scars led to an increase in excretion of collagen degradation products, the rate of the increase depended on area and age of scar. In hypertrophic cicatrization rate of collagen metabolites excretion correlated with the scar age reversely, demonstrating the tendency to decrease of the scar collagen metabolites with its ageing. Excretion of collagen metabolites with urine in patients with keloid scars depended on area of the scar and only slightly on its age. Besides, in patients with keloids rather high, statistically distinct correlation (r = 0.855) was found between the ratio macrophages/neutrophils under studies using "skin window" as well as between the ratio of hydroxyproline content in the polypeptide fractions with molecular mass above 1,500 and in the fraction containing oligopeptides and free hydroxyproline. This correlation was not found in patients with hypertrophic scars. Interaction of macrophages, neutrophils and, probably, eosinophiles appears to have a definite importance in regulation of collagen degradation, impairment of which may be substantial for scars formation.