To determine whether the proteinuria, glomerular sclerosis, and decline in glomerular filtration rate (GFR) described in rodents after renal mass reduction develop in another species, 24-hour proteinuria, glomerular structure, and fasting and postfeeding GFR were examined in dogs subjected to seven-eighths reduction in renal mass. All dogs were fed a diet containing 26% protein. Six dogs with a GFR <10 ml/min (8% to 17% of control two-kidney GFR) were killed within 6 months after renal mass reduction. Twenty-four-hour urinary protein excretion was modestly although definitely increased (236 ± 26 mg/24 hr, P < 0.01). All remnant kidneys demonstrated structural changes in mesangial hyperplasia or focal glomerular sclerosis. Ten dogs with a remnant kidney and early GFRs 16% to 39% of control values were followed for 18 to 39 months. In seven dogs, GFR showed little tendency to decrease with time. In one of them, proteinuria was 106 mg/24 hr with normal-appearing glomeruli at 14 months. In three dogs, proteinuria was progressive, averaging about 1 gm/24 hr at 18 months and 2 gm/24 hr at 24 to 34 months; glomerular pathologic findings progressed from focal mesangial hyperplasia or focal glomerular sclerosis at 8 to 16 months to focal and segmental sclerosis or diffuse glomerular absolescence at 25 to 34 months; and fasting GFR progressively declined starting at 21 to 24 months after renal mass reduction. Whereas GFR increased after feeding 1 to 2 gm protein per kilogram much less (P < 0.01) in dogs with a remnant kidney (from 15.9 ± 1.4 to 19.8 ± 1.7 ml/min) than in normal dogs (from 42.7 ± 1.8 to 53.9 ± 2.1 ml/min), the relative increase in GFR was equivalent, 24.3% ± 3.4% vs. 27.1% ± 3.9%, in the two groups. Thus, reduction of renal mass in dogs, as in rodents, results in a proteinuric glomerulopathy, the severity of which appears proportional to the amount of renal mass ablated and which precedes the decline in GFR. The presence of a glomerular filtration reserve in fasting dogs with a remnant kidney may help support GFR and delay its progressive decline.
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of Laboratory and Clinical Medicine|
|State||Published - Jan 1 1987|
ASJC Scopus subject areas
- Pathology and Forensic Medicine