DECREASED EXCRETION OF GLYCOSAMINOGLYCANS IN PATIENTS WITH PRIMARY GLOMERULAR-DISEASES

Urine glycosaminoglycans (GAG) concentrations were measured in 150 pat ients with primary glomerulonephritides: endocapillary glomerulonephri tis, mesangial proliferative glomerulonephritis, IgA nephropathy, memb ranous glomerulonephritis and minimal change nephropathy, and in 63 he althy controls and 19 patients with diabetes nephropathy. The urine GA G to creatinine ratios (GCR) were significantly reduced (p < 0.01) in all the glomerulonephritides investigated (0.20 mg/mmol in endocapilla ry glomerulonephritis, 1.60 mg/mmol in mesangial proliferative glomeru lonephritis, 1.74 mg/mmol in IgA nephropathy, 1.09 mg/mmol in membrano us nephropathy and 1.16 mg/mmol in minimal change nephropathy compared to healthy controls (2.87 mg/mmol) but not compared to diabetes patie nts (1.17 mg/mmol). Also, the GCR in a group of 23 non-albuminuric glo merulonephritis patients (1.98 mg/mmol) was shown to be significantly decreased (p < 0.01) compared to healthy controls. Moreover, the GCR w as significantly lower (p < 0.01) in endocapillary glomerulonephritis than in any of the other diseases studied. The GAG excretion per funct ioning glomerular area, calculated as fractional GAG excretion (FGE), was decreased in all the glomerulonephritides investigated compared to both healthy controls and diabetes nephropathy. The decreased GAG exc retion in glomerulonephritides, obtained in the present study, might b e a consequence of decreased synthesis or turnover of GAG in the funct ioning nephrons whereas the mechanisms for the reduced GAG excretion i n diabetes nephropathy might be of a different nature. Urinary GAG exc retion in this group of glomerular disorders and particularly in endoc apillary glomerulonephritis, may lead to new approaches in non-invasiv e renal diagnostics and, particularly with regard to the differentiati on of acute and chronic forms of glomerulonephritides.