Rapid progression of diabetic nephropathy is linked to inflammation and episodes of acute renal failure.

BACKGROUND/AIMS: Chronic kidney disease (CKD) from diabetic nephropathy is characterized by progressive loss of renal function. The renal decline has been viewed as a linear fall, presumably dependent on metabolic, hemodynamic and dietary stresses. However, renal injury in diabetic nephropathy can be rapidly aggravated by unpredictable external and internal factors, a state of affairs inconsistent with a linear loss of function. Acute renal injury and subsequent inflammation are potential factors, and we investigated their presence in renal biopsies from patients with nephropathy.

METHODS

In a protocol approved by the Indiana University School of Medicine Institutional Review Board, renal biopsy specimens, estimated GFR, proteinuria and renal survival were examined in patients with diabetic nephropathy.

RESULTS

Prominent clusters of inflammatory cells, particularly macrophages, were detected in the renal biopsy specimens. CKD progressed rapidly but not linearly, in that CKD was characterized by a succession of seemingly random episodes of self-limited acute renal failure. Episodes of acute kidney injury were associated with progression to end-stage renal disease.

CONCLUSIONS

We propose that diabetic nephropathy is complicated by unpredictable and possibly random episodes of usually self-limited acute renal failure, and by subsequent renal inflammation, which appear to accelerate progression and eventual kidney loss.