TY - JOUR
T1 - Glycosylation of human glomerular basement membrane collagen
T2 - Increased content of hexose in ketoamine linkage and unaltered hydroxylysine-o-glycosides in patients with diabetesd
AU - Uitto, Jouni
AU - Perejda, Andrea J.
AU - Grant, Gregory A.
AU - Rowold, Edwin A.
AU - Kilo, Charles
AU - Williamson, Joseph R.
N1 - Funding Information:
This work was supported in part by USPHS NIH grants HL-13694, AM-28450 and GM-28833. and grants by the American Diabetes Association, Southern California Affiliate, Inc., and the Kilo Diabetes and Vascular Research Foundation. Dr. Uitto is recipient of Research Career Development Award 5-KO6AM 00897 from the National Institutes of Health. Dr. Perejda is Advanced Research Fellow of the American Heart Association, Greater Los Angeles Affiliate.
PY - 1982
Y1 - 1982
N2 - To study the glycosylation of glomerular basement membrane collagen (GBMC) in diabetes, kidneys were obtained at autopsy from 5 patients with insulin-requiring diabetes of long duration and diabetic complications, and from 5 control subjects. Glomeruli were prepared by sieving and collagen was isolated by limited pepsin proteolysis followed by salt precipitations. Amino acid analyses of the collagen preparations, after acid hydrolysis, indicated a composition consistent with that of type IV collagen. No differences in the relative contents of various amino acids, and in particular, 3-hydroxyproline, 4-hydroxyproline and hydroxylysine, were noted between diabetic and control samples. Non-enzymatic glucosylation was assessed by measuring hexose in ketoamine linkage with thiobarbituric acid after conversion to 5-hydroxymethylfurfural. In 4 of the 5 patients studied, glucosylation values exceeded the mean +2 S. D. of the controls; in the fifth subject glucosylation was in the high normal range. No correlation between the severity of diabetes and hexose content of GBMC was noted, however. In further studies, enzymatic glycosylation of GBMC was assayed after alkaline hydrolysis by separation of glucosylgalactosyl-O-hydroxylysine, galactosyl-O-hydroxylysine, and unsubstituted hydroxylysine in an amino acid analyzer. No differences in the relative contents of hydroxylysine-O-glycosides were evident between diabetic and control GBMC. The results suggest that non-enzymatic glucosylation, but not glycosylation catalyzed by collagen glucosyl and galactosyl transferases, is increased in diabetes. The increased carbohydrate content of collagen may lead to decreased turnover and/or excessive accumulations of basement membrane collagen thus contributing to the vascular complications of diabetes.
AB - To study the glycosylation of glomerular basement membrane collagen (GBMC) in diabetes, kidneys were obtained at autopsy from 5 patients with insulin-requiring diabetes of long duration and diabetic complications, and from 5 control subjects. Glomeruli were prepared by sieving and collagen was isolated by limited pepsin proteolysis followed by salt precipitations. Amino acid analyses of the collagen preparations, after acid hydrolysis, indicated a composition consistent with that of type IV collagen. No differences in the relative contents of various amino acids, and in particular, 3-hydroxyproline, 4-hydroxyproline and hydroxylysine, were noted between diabetic and control samples. Non-enzymatic glucosylation was assessed by measuring hexose in ketoamine linkage with thiobarbituric acid after conversion to 5-hydroxymethylfurfural. In 4 of the 5 patients studied, glucosylation values exceeded the mean +2 S. D. of the controls; in the fifth subject glucosylation was in the high normal range. No correlation between the severity of diabetes and hexose content of GBMC was noted, however. In further studies, enzymatic glycosylation of GBMC was assayed after alkaline hydrolysis by separation of glucosylgalactosyl-O-hydroxylysine, galactosyl-O-hydroxylysine, and unsubstituted hydroxylysine in an amino acid analyzer. No differences in the relative contents of hydroxylysine-O-glycosides were evident between diabetic and control GBMC. The results suggest that non-enzymatic glucosylation, but not glycosylation catalyzed by collagen glucosyl and galactosyl transferases, is increased in diabetes. The increased carbohydrate content of collagen may lead to decreased turnover and/or excessive accumulations of basement membrane collagen thus contributing to the vascular complications of diabetes.
UR - http://www.scopus.com/inward/record.url?scp=0020368133&partnerID=8YFLogxK
U2 - 10.3109/03008208209008054
DO - 10.3109/03008208209008054
M3 - Article
C2 - 6218960
AN - SCOPUS:0020368133
SN - 0300-8207
VL - 10
SP - 287
EP - 296
JO - Connective Tissue Research
JF - Connective Tissue Research
IS - 3-4
ER -