title: Collagen synthesis and degradation in polyneuropathy and myopathies.
abstract: To determine the mechanisms underlying the changes in collagen metabolism responsible for muscle fibrosis in patients with neuromuscular diseases, the synthesis and degradation of collagens was studied in muscles of patients with polyneuropathy and noninflammatory myopathies. The mRNA levels for type I, III, and IV collagens and immunohistochemical staining intensities for collagen propeptides and telopeptides were increased in polyneuropathy, suggesting enhanced synthesis of collagens. In myopathy, the mRNA levels were at the control level. Matrix metalloproteinase (MMP)-2 mRNA level was increased in polyneuropathy, although the quantity of proMMP-2 was not changed. An increase in type IV collagen concentration and proMMP-9 expression was observed in polyneuropathy but not in myopathies. Our results suggest that intramuscular accumulation of type IV collagen occurs in polyneuropathy, possibly leading to thickening of the capillary and muscle fiber basement membranes. This may complicate the transportation of nutrients and cellular excreta between blood and muscle cells.
authors.affiliation: Department of Physiology, University of Oulu, P.O. Box 5000, 90014 Oulun Yliopisto, Finland. anne.ahtikoski@oulu.fi <anne.ahtikoski@oulu.fi>
authors.forename: Anne M
authors.initials: AM
authors.lastname: Ahtikoski
authors.forename: Hannu
authors.initials: H
authors.lastname: Tuominen
authors.forename: Juha T
authors.initials: JT
authors.lastname: Korpelainen
authors.forename: Timo E S
authors.initials: TE
authors.lastname: Takala
authors.forename: Aarne
authors.initials: A
authors.lastname: Oikarinen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003094:Collagen / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D024141:Collagen Type IV / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D009468:Neuromuscular Diseases / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D011115:Polyneuropathies / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018709:Statistics, Nonparametric
chemical_list: D024141:Collagen Type IV; D012333:RNA, Messenger; D003094:Collagen; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9