To determine the mechanisms underlying the changes in collagen metabolism resp onsible for muscle fibrosis in patients with neuromuscular diseases, the synthes is and degradation of collagens was studied in muscles of...To determine the mechanisms underlying the changes in collagen metabolism resp onsible for muscle fibrosis in patients with neuromuscular diseases, the synthes is and degradation of collagens was studied in muscles of patients with polyneur opathy and noninflammatory myopathies. The mRNA levels for type I, III, and IV c ollagens and immunohistochemical staining intensities for collagen propeptides a nd telopeptides were increased in polyneuropathy, suggesting enhanced synthesis of collagens. In myopathy, the mRNA levels were at the control level. Matrix met alloproteinase (MMP) 2 mRNA level was increased in polyneuropathy, although the quantity of proMMP 2 was not changed. An increase in type IV collagen concentr ation and proMMP 9 expression was observed in polyneuropathy but not in myopath ies. Our results suggest that intramuscular accumulation of type IV collagen occ urs in polyneuropathy, possibly leading to thickening of the capillary and muscl e fiber basement membranes. This may complicate the transportation of nutrients and cellular excreta between blood and muscle cells.展开更多
文摘To determine the mechanisms underlying the changes in collagen metabolism resp onsible for muscle fibrosis in patients with neuromuscular diseases, the synthes is and degradation of collagens was studied in muscles of patients with polyneur opathy and noninflammatory myopathies. The mRNA levels for type I, III, and IV c ollagens and immunohistochemical staining intensities for collagen propeptides a nd telopeptides were increased in polyneuropathy, suggesting enhanced synthesis of collagens. In myopathy, the mRNA levels were at the control level. Matrix met alloproteinase (MMP) 2 mRNA level was increased in polyneuropathy, although the quantity of proMMP 2 was not changed. An increase in type IV collagen concentr ation and proMMP 9 expression was observed in polyneuropathy but not in myopath ies. Our results suggest that intramuscular accumulation of type IV collagen occ urs in polyneuropathy, possibly leading to thickening of the capillary and muscl e fiber basement membranes. This may complicate the transportation of nutrients and cellular excreta between blood and muscle cells.
