Serum type IV collagen concentrations in diabetic patients with microangiopathy as determined by enzyme immunoassay with monoclonal antibodies.
In long-term diabetes mellitus, thickening of basement membrane in capillaries and small vessels is a characteristic lesion and plays an important role in the progression of diabetic microangiopathy. We have developed a sandwich enzyme immunoassay for human serum type IV collagen peptide with monoclonal antibodies. Previous studies suggested that collagen levels reflect the activity of fibrogenesis in basement membrane. Serum type IV collagen levels were measured in 137 non-insulin-dependent diabetic patients (aged 50-75 yr) with or without clinical signs of retinopathy, nephropathy, and/or neuropathy and 110 healthy subjects (aged 50-75 yr) without serological abnormality. Serum concentrations of type IV collagen were significantly higher (P less than 0.01) in diabetic patients (mean +/- SE 124.1 +/- 4.1 ng/ml) than in healthy subjects (73.9 +/- 2.2 ng/ml) and were increased with the prevalence or incidence of diabetic complications. In the patients with diabetic microangiopathy, serum type IV collagen levels became higher as clinical signs worsened. Especially in the patients with diabetic nephropathy, serum type IV collagen levels became higher with elevation of blood urea nitrogen, serum creatinine, and serum beta 2-microglobulin but not urinary excretion of beta 2-microglobulin and N-acetyl-beta-glucosaminidase. These observations indicated that elevation of serum type IV collagen in diabetic nephropathy was related to glomerular filtration dysfunction rather than renal tubular dysfunction. However, the antigen, which can be detected by our assay system, did not exist in urine specimens of healthy subjects, and an intimate relationship was not observed between serum type IV collagen level and serum creatinine level.(ABSTRACT TRUNCATED AT 250 WORDS)
First Department of Medicine, Wakayama University of Medical Science, Japan.
E
E
Matsumoto
G
G
Matsumoto
A
A
Ooshima
H
H
Kikuoka
H
H
Bessho
K
K
Miyamura
K
K
Nanjo
D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D001609:Beta-Globulins / Q000032:analysis; D001806:Blood Urea Nitrogen; D003094:Collagen / Q000097:blood* / Q000276:immunology; D003401:Creatine / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications; D003925:Diabetic Angiopathies / Q000097:blood* / Q000209:etiology; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000378:metabolism
D000911:Antibodies, Monoclonal; D001609:Beta-Globulins; D003094:Collagen; D003401:Creatine; D006442:Glycated Hemoglobin