Diabetes, Vol 46, Issue 11 1875-1880, Copyright © 1997 by American Diabetes Association
Immunohistochemical quantification of heparan sulfate proteoglycan and collagen IV in skeletal muscle capillary basement membranes of patients with diabetic nephropathy
H Yokoyama, PE Hoyer, PM Hansen, J van den Born, T Jensen, JH Berden, T Deckert and C Garbarsch
Steno Diabetes Center, Gentofte, Denmark.
In IDDM patients, an increased permeability of the glomerular capillaries
has been associated with a general loss of negatively charged heparan
sulfate proteoglycans (HSPGs) within basement membranes (BMs). In the
present study, we used immunohistochemical staining to quantify heparan
sulfate (HS), HSPG core protein, and collagen IV in capillary basement
membranes of skeletal muscle biopsies taken from 9 healthy control subjects
(C) and 20 IDDM patients: 7 with normal albumin excretion rate (<30
mg/24 h) (D0), 5 with incipient nephropathy (albumin excretion rate 30-300
mg/24 h) (D1), and 8 with clinical nephropathy (albumin excretion rate
>300 mg/24 h) (D2). In the capillaries, staining was measured by a
scanning and integrating microspectrophotometer. A significant difference
in the absorbance of HS was found among the four subgroups (means +/- SD):
0.477 +/- 0.082 (C), 0.627 +/- 0.031 (D0), 0.542 +/- 0.098 (D1), and 0.371
+/- 0.118 (D2) (P = 0.006). Similarly, an overall significant difference in
the absorbance of collagen IV was demonstrated (means +/- SD): 0.836 +/-
0.111 (C), 0.838 +/- 0.300 (D0), 0.970 +/- 0.173 (D1), and 0.512 +/- 0.248
(D2) (P = 0.02). No statistical difference in the absorbance of core
protein was demonstrated among the groups. Within the diabetic groups, HS
was inversely correlated to albuminuria (r = -0.76, P = 0.003) and
albuminuria corrected for creatinine clearance (r = -0.69, P = 0.008).
Because, in IDDM patients with albuminuria, alterations of the content of
HS and collagen IV within the capillary BM have been demonstrated
immunohistochemically, not only in the glomerular filtration barrier, but
also in the skeletal muscle capillary BM, we suggest that these changes
reflect universal quantitative or qualitative alterations within the
capillary filtration barrier.