lisinopril and Nephritis--Interstitial

In proteinuric glomerulopathies, the excess traffic of proteins into the renal tubule is a candidate trigger of interstitial inflammatory and immune events leading to progressive injury, and a key target for the renoprotective action of antiproteinuric drugs. Among proteins trafficked to the proximal tubule, the third component of complement (C3) can be activated locally and contribute to inflammation at sites of protein reabsorption. Experiments were performed in rats with renal mass reduction (RMR, 5/6 nephrectomy) with the following aims: (1) to study Ig (IgG) and complement deposition in proximal tubules, and interstitial macrophage infiltration and MHC class II expression at intervals after surgery by double immunofluorescence analysis; (2) to assess whether lisinopril (angiotensin-converting enzyme inhibitor [ACEi], 25 mg/L in the drinking water, from either day 1 or day 7) limited IgG and C3 accumulation and interstitial inflammation at day 30. In 7-d remnant kidneys, intracellular staining for both IgG and C3 was detectable in proximal tubules in focal areas; C3 was restricted to IgG-positive tubular cells, and there were no interstitial ED-1 macrophage and MHC II-positive cellular infiltrates. In 14-d and 30-d remnant kidneys, proximal tubular IgG and C3 staining was associated with the appearance of interstitial infiltrates that preferentially localized to areas of tubules positive for both proteins. RMR rats given ACEi had no or limited increases in levels of urinary protein excretion, tubular IgG, and C3 reactivity, and interstitial cellular infiltrates in kidneys at 30 d, even when ACEi was started from day 7 after surgery. These findings document that (1) in RMR, IgG and C3 accumulation in proximal tubular cells is followed by leukocyte infiltration and MHC II overexpression in the adjacent interstitium; (2) ACEi while preventing proteinuria limits both tubular accumulation of IgG and C3 and interstitial inflammation. The data suggest that ACE inhibition can be renoprotective by limiting the early abnormal protein traffic in proximal tubule and consequent deleterious effects of excess protein reabsorption, including the accumulation and local activation of complement as well as the induction of chemokines and endothelin genes known to promote interstitial inflammation and fibrosis.

Topics: Analysis of Variance; Animals; Complement C3 Nephritic Factor; Culture Techniques; Disease Models, Animal; Genes, MHC Class II; Immunoglobulin G; Immunohistochemistry; Inflammation; Kidney Tubules, Proximal; Lisinopril; Macrophages; Male; Nephrectomy; Nephritis, Interstitial; Proteinuria; Rats; Rats, Sprague-Dawley; Reference Values

We previously reported the renal hemodynamic effects of different antihypertensive regimens in uninephrectomized, alloxan-induced, diabetic (DM) beagle dogs following one year of treatment. Dogs were prospectively randomized to one of five groups (N = 26): nondiabetic controls, Group I; dogs with DM on no antihypertensive drugs, Group II; dogs on a converting enzyme inhibitor, lisinopril (L), Group III; dogs on a calcium antagonist, TA3090 (diltiazem-like), Group IV; and dogs on a combination of each drug, in reduced doses, Group V. The current paper extends our previous studies by describing the morphologic changes that occurred within each group of dogs studied. More than 100 glomeruli from the renal cortex of each dog were evaluated for increases in mesangial volume fraction (Vv), glomerulosclerosis (GS) and ateriolar hyalinosis. The interstitium was also evaluated for associated changes. Increases in Vv were attenuated in all treated groups (0.28 +/- 0.04, DM alone versus 0.16 +/- 0.05 L; 0.21 +/- 0.07, TA-3090; 0.19 +/- 0.06 micron 2/micron 2, L+TA 3090; P < 0.05) compared to untreated DM. An attenuated increase in Vv also correlated with a blunted rise in proteinuria in Groups III (r = 0.79) and V (r = 0.81) but not Group IV (r = 0.29). Development of focal GS was blunted in all treated groups; however, global GS was fourfold greater in Group IV compared to untreated DM. The degree of interstitial fibrosis also correlated with the degree of global GS. These data support the concept that both a converting enzyme inhibitor and heart rate lowering calcium antagonist attenuate morphologic progression of diabetic renal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antihypertensive Agents; Diabetic Nephropathies; Diltiazem; Dogs; Drug Therapy, Combination; Fibrosis; Glomerular Mesangium; Glomerulosclerosis, Focal Segmental; Lisinopril; Nephrectomy; Nephritis, Interstitial