Renal protective effect of candesartan cilexetil in spontaneously hypercholesterolemic rats

Spontaneously hypercholesterolemic (SHC) rats exhibit hypercholesterolemia, proteinuria and focal glomerulosclerosis with age, and they finally die as a result of renal failure. In this study, the renoprotective effects of candesartan cilexetil, an angiotensin II type 1 receptor antagonist, and enalapril, an angiotensin I converting enzyme inhibitor, were examined in SHC rats. Candesartan cilexetil (0.1 and 1 mg /kg) and enalapril (10 mg/kg) were administered orally to 10-week-old SHC rats for a 6-week period. Candesartan cilexetil (1 mg/kg) and enalapril (10 mg/kg) significantly inhibited proteinuria and hypercholesterolemia to a similar extent. In untreated 16-week-old SHC rats, glomerulosclerosis, basophilic change, cast formation and interstitial mononuclear cell infiltration were observed. Candesartan cilexetil (1 mg/kg) inhibited all of these histological changes. Enalapril inhibited glomerulosclerosis and cast formation. These results show that candesartan cilexetil and enalapril have renal protective effects in SHC rats. Thus, angiotensin II might play an important role in renal pathogenesis in a model of focal glomerulosclerosis with hypercholesterolemia.

Temocapril, a long-acting non-SH group angiotensin converting enzyme inhibitor, modulates glomerular injury in chronic puromycin aminonucleoside nephrosis

The purpose of the present study was to determine whether chronic administration of temocapril, a long-acting non-SH group angiotensin converting enzyme (ACE) inhibitor, reduced proteinuria, inhibited glomerular hypertrophy and prevented glomerulosclerosis in chronic puromycin aminonucleoside (PAN) - induced nephrotic rats. Nephrosis was induced by injection of PAN (15mg/100g body weight) in male Sprague-Dawley (SD) rats. Four groups were used, i) the PAN group (14), ii) PAN/temocapril (13), iii) temocapril (14) and iv) untreated controls (15). Temocapril (8 mg/kg/day) was administered to the rats which were killed at weeks 4, 14 or 20. At each time point, systolic blood pressure (BP), urinary protein excretion and renal histopathological findings were evaluated, and morphometric image analysis was done. Systolic BP in the PAN group was significantly high at 4, 14 and 20 weeks, but was normal in the PAN/temocapril group. Urinary protein excretion in the PAN group increased significantly, peaking at 8 days, then decreased at 4 weeks, but rose again significantly at 14 and 20 weeks. Temocapril did not attenuate proteinuria at 8 days, but it did markedly lower it from weeks 4 to 20. The glomerulosclerosis index (GSI) was 6.21 % at 4 weeks and respectively 25.35 % and 30.49 % at 14 and 20 weeks in the PAN group. There was a significant correlation between urinary protein excretion and GSI (r = 0.808, p < 0.0001). The ratio of glomerular tuft area to the area of Bowman's capsules (GT/BC) in the PAN group was significantly increased, but it was significantly lower in the PAN/temocapril group. It appears that temocapril was effective in retarding renal progression and protected renal function in PAN neprotic rats.

Protective effects of vitamin E and selenium on the renal morphology in rats fed high-cholesterol diets

The histopathological effects of cholesterol and the protective effects of vitamin E and selenium (Se) on renal histology were examined in Sprague-Dawley rats. Light-microscopic evaluation of the renal cortex revealed: glomerular fibrosis, cellular and mesangial proliferation, capillary obliteration and cholesterol crystals in the tubular lumina of the cholesterol-fed group. These results suggest that oxidated LDL (O-LDL) is a cytotoxic factor which stimulates mesangial cell and matrix proliferation. Ultrastructurally, small and large lipid vacuolization in intracapillary lumina, adhesion of epithelial foot processes, mesangial foam cells and polymorphonuclear leukocytes were seen in the cholesterol-fed group. In the groups fed cholesterol + vitamin E, cholesterol + Se and cholesterol + vitamin E + Se, morphological improvements were observed. It appeared that an excess in O-LDL, reactive oxygen species and growth factors might play an important role in the pathogenesis of glomerulosclerosis. In addition, it was concluded that antioxidant therapy may prevent LDL oxidation and generation of free radicals.

Peroxisome proliferator-activated receptor-gamma agonist troglitazone protects against nondiabetic glomerulosclerosis in rats

BACKGROUND

Peroxisome proliferator-activated receptor-gamma (PPAR gamma) is a member of the nuclear receptor superfamily of ligand-dependent transcriptional factors with beneficial effects in diabetes mediated by improved insulin sensitivity and lipid metabolism, but potential adverse effects in atherosclerosis by promoting in vitro foam cell formation. We explored whether a PPAR gamma agonist, troglitazone (TGL), affects sclerosis by mechanisms unrelated to insulin and lipid effects in a model of nondiabetic glomerulosclerosis.

METHODS

Adult male Sprague Dawley rats underwent 5/6 nephrectomy and were treated for 12 weeks as follows: control (CONT), no further treatment; triple antihypertensive therapy (TRX); and TGL or TGL + TRX. Functional, morphological, and molecular analyses were performed.

RESULTS

Systolic blood pressure (SBP) was increased in CONT and TGL groups (161 +/- 1 and 160 +/- 3 mm Hg), but not in TGL + TRX and TRX (120 +/- 3 vs. 126 +/- 1 mm Hg, P < 0.0001 vs. non-TRX). Serum triglyceride and cholesterol levels in all groups remained normal except for slightly higher serum cholesterol levels in TRX group. TGL groups had reduced proteinuria, serum creatinine, and glomerulosclerosis versus CONT, in contrast to no significant effect with TRX alone (sclerosis index, 0 to 4+ scale: CONT 1.99 +/- 0.42, TGL 0.85 +/- 0.12, TGL + TRX 0.56 +/- 0.14, TRX 1.30 +/- 0.21; TGL, P < 0.05; TGL + TRX, P = 0.01 vs. CONT). Glomerular cell proliferation, assessed by proliferating cell nuclear antigen (PCNA), was decreased after treatment with TGL or TGL + TRX, in parallel with decreases in glomerular p21 mRNA and p27 protein compared with CONT and TRX (PCNA + cells/glomerulus: CONT 2.04 +/- 0.64, TGL 0.84 +/- 0.21, TGL + TRX 0.30 +/- 0.07, TRX 1.38 +/- 0.37; TGL, P < 0.05, TGL + TRX, P < 0.01 vs. CONT). Glomerular plasminogen activator inhibitor-1 (PAI-1) immunostaining was decreased in TGL or TGL + TRX groups (0 to 4+ scale, CONT 2.42 +/- 0.32, TGL 1.40 +/- 0.24, TGL + TRX 1.24 +/- 0.17, TRX 2.53 +/- 0.24; TGL or TGL + TRX vs. CONT, P < 0.05), with a parallel decrease in PAI-1 mRNA by in situ hybridization. Glomerular and tubular transforming growth factor-beta (TGF-beta) mRNA expression was decreased with TGL treatment. Glomerular macrophages, present in CONT and TRX rats, did not express PPAR gamma, in contrast to PPAR gamma + macrophages in control carotid artery plaque. PPAR gamma was expressed in resident cells.

CONCLUSIONS

Our results demonstrate in vivo that the PPAR gamma ligand TGL ameliorates the progression of glomerulosclerosis in a nondiabetic model. Macrophages show phenotypic diversity in glomerular versus vascular sclerosis, with macrophage PPAR gamma expression in only the latter. PPAR gamma beneficial effects are independent of insulin/glucose effects and are associated with regulation of glomerular cell proliferation, hypertrophy, and decreased PAI-1 and TGF-beta expression.

Atorvastatin prevents glomerulosclerosis and renal endothelial dysfunction in hypercholesterolaemic rabbits

BACKGROUND

Numerous studies have shown that elevated plasma cholesterol can exacerbate renal disease. However, the effect of lipids on renal structure and vascular function in normal kidneys is less well established. Therefore, the aim of this study was to evaluate the impact of hypercholesterolaemia on glomerular structure and vascular reactivity of segmental arteries in rabbits. In addition, we also studied whether or not atorvastatin can prevent these structural and vascular alterations in hypercholesterolaemic rabbits.

METHODS

Male New Zealand rabbits were fed either a normal rabbit chow or a diet containing 1% cholesterol and treated or not with atorvastatin (1 mg/kg/day) for 12 weeks. Dose-response curves to acetylcholine (10(-9)-10(-4) mol/l) and sodium nitroprusside (10(-9)-10(-4) mol/l) were studied in segmental arteries in the presence or absence of the thromboxane A2/PGH2 receptor antagonist ifetroban (10(-5) mol/l). Glomerular size and structure were also evaluated.

RESULTS

Compared with control animals, hypercholesterolaemic rabbits presented glomerular hypertrophy and several types of injuries (capillary collapse, hyalinosis and alterations of Bowman's capsule), suggesting diffuse glomerulosclerosis. Segmental arteries also showed relaxing responses to acetylcholine and sodium nitroprusside which were lower than and similar to, respectively, those of control animals. The presence of ifetroban improved the acetylcholine response only in hypercholesterolaemic rabbits. Atorvastatin treatment prevented vascular and most glomerular changes associated with hypercholesterolaemia even in the presence of very high cholesterol levels.

CONCLUSIONS

Atorvastatin exerts a protective effect on renal damage associated with hypercholesterolaemia even in the presence of deleterious levels of plasma cholesterol.

Effect of pre-and postoperative plasmapheresis on posttransplant recurrence of focal segmental glomerulosclerosis in children

BACKGROUND

Posttransplant recurrence is frequent in patients who received renal transplantation for focal segmental glomerulosclerosis (FSGS). The recurrence has been ascribed to a circulating permeability factor or factors. We have used plasmapheresis (PP) to treat recurrent FSGS and also studied whether preoperative PP is effective in preventing recurrence of FSGS.

METHODS

We retrospectively analyzed 21 allografts of 20 patients with nephrotic syndrome and biopsyproven FSGS. They were divided into two groups depending on whether they had prophylactic PP; a prophylactic (n=15) and a nonprophylactic group (n=6). PP was performed two to three times prophylactically and therapeutically until proteinuria was markedly reduced. In each session, 50-75 ml/kg of the patient's plasma was exchanged with 5-8% albumin.

RESULTS

FSGS recurred in 9 of 21 allografts, 4 of 6 in the nonprophylactic group, and 5 of 15 in the prophylactic group. Therapeutic PP was performed in seven of nine recurrent patients without definite adverse effect, with satisfactory results except in one patient. Children lost proteinuria after 6 to > 100 sessions of PP and the number correlated with the pretreatment level of proteinuria. The mean follow-up periods were 62.7 and 41.6 months for the prophylactic and nonprophylactic groups, respectively. At the last follow-up, 66.7% of relapsing and 81.8% of nonrelapsing patients had a functioning graft.

CONCLUSION

PP appears to be effective for the prevention and treatment of posttransplant recurrence of FSGS, although further consideration of cost/benefit and risks is required before a conclusive judgement can be made.

[Study on mechanism of Shenle and Fragmin in preventing and treating glomerulosclerosis in rats]

OBJECTIVE

To study the effects of Shenle and Fragmin on the degradation of extracellular matrix metalloproteinase-9 (MMP-9) and tissue inhibitors of metalloproteinase-1 (TIMP-1) in the remnant kidneys of 5/6 nephrectomized rats treated with Shenle and Fragmin.

METHODS

The model of focal and segmental glomerulosclerosis was made by 5/6 nephrectomy in Wistar rats. After being treated with Shenle (4 g.kg-1.d-1) or Fragmin (1000 IU.kg-1.d-1) for 20 weeks, the blood pressure, proteinuria, serum creatinine, lipids, renal pathological change of remnant kidney of the model animals were examined, and the mRNA expression of MMP-9, TIMP-1 and type IV collagen in the remnant kidney were also detected.

RESULTS

Shenle and Fragmin could significantly reduce the blood pressure, proteinuria, serum creatinine and lipids, alleviate the pathologic change of kidney tissue, decrease the type IV collagen, MMP-9 deposition. Shenle and Fragmin down-regulated the mRNA expression of MMP-9 by 30.0% and 28.5% and TIMP-1 expression by 59.3% and 55.0% in the remnant kidney of the 5/6 nephrectomized rats respectively.

CONCLUSION

Shenle and Fragmin might ameliorate glomerulosclerosis through modulating MMP-9/TIMP-1 gene expression, alleviate the abnormal metabolism and accumulation, promote extracellular matrix degradation in glomeruli remodeling, it might be the important mechanism of Shenle and Fragmin in treating glomerulosclerosis.

Significant suppressive effect of low-dose temocapril, an ACE inhibitor with biliary excretion, on FGS lesions in hypertensive rats

To investigate how the interruption of the renin-angiotensin system (RAS) and reduction of blood pressure (BP) affect the lesions of chronic focal and segmental glomerulosclerosis (FGS), we studied the effects of high and low doses of angiotensin-converting enzyme inhibitors (temocapril - TEM) a newly developed ACE inhibitor with biliary tract excretion, on the hypertensive model of FGS. A high dose of TEM significantly lowered BP and suppressed both intense proteinuria and glomerular extracapillary lesions including macrophage infiltration. On the other hand, although a low dose of TEM did not significantly lower BP throughout the experimental period, it prevented renal lesions almost in the same manner as high-dose TEM with suppression of c-myc gene expression in glomeruli. These findings suggest that in PAN-induced chronic FGS, the systemic BP elevation could not be the major factor for the progression of renal damage which TEM could prevent without significant lowering of BP.

Impact of angiotensin II on the kidney: does an angiotensin II receptor blocker make sense?

The renin-angiotensin system (RAS) regulates blood pressure, volume, and electrolyte balance. Derangements of the RAS may contribute to hypertension and renal injury, particularly in patients with types 1 or 2 diabetes. Angiotensin-converting enzyme (ACE) inhibitors have been proven to be beneficial in patients with hypertension and diabetes by preventing or delaying the development and progression of proteinuria and glomerulosclerosis. Comparisons with other drug classes demonstrate renoprotective effects for ACE inhibitors that are independent of-and additive to-their systemic antihypertensive actions. These renal effects may derive from their preferential dilation of renal efferent arterioles, which further reduces intraglomerular pressure. Inhibition of angiotensin II (Ang II) synthesis is subtotal, however, because local non-ACE enzymes also convert Ang I to Ang II. The existence of alternative pathways for Ang II generation that are unaffected by ACE inhibitors raises questions about whether ACE is the optimal target for RAS suppression. Ang II receptor blockers (ARBs), which interrupt the RAS at the target-organ receptor level, will block the effect of angiotensin whether its production involved ACE or a non-ACE pathway. ARBs are currently undergoing clinical trials to assess their efficacy in hypertensive patients with nephropathy.

Long-term outcome of liver transplantation in patients with glycogen storage disease type Ia

Liver transplantation may be indicated in patients with GSD type Ia when dietary treatment fails or when hepatic adenomas develop, because they carry a risk of liver cancer or severe intratumoral haemorrhage. Published reports on the results of liver transplantation in patients with GSD Ia include 10 patients and provide little information on long-term outcome. In particular, it is not known whether liver transplantation prevents renal failure due to focal segmental glomerulosclerosis. We report here on 3 patients with GSD Ia in whom liver transplantation was performed at 15, 17 and 23 years of age because of multiple hepatic adenomas in all 3 patients with a fear of malignant transformation, and of poor metabolic balance and severe growth retardation in the youngest one. Renal function was normal in all patients. During the 6-8 years following transplantation, the quality of life has initially greatly improved, with none of the previous dietary restraints and a spectacular increase in height. However, long-term complications included chronic hepatitis C in one patient, gouty attacks in another and focal segmental glomerulosclerosis with progressive renal insufficiency in the third. These results: (1) confirm that liver transplantation restores a normal metabolic balance in patients with GSD Ia, allows catch-up growth and improves the quality of life; (2) suggest that liver transplantation may be considered in teenagers with unresectable multiple adenomas because of a lack of clear-cut criteria to detect malignant transformation early; and (3) suggest that liver transplantation does not prevent focal segmental glomerulosclerosis associated with GSD Ia.

Effect of proteinuria reduction on prevention of focal glomerulosclerosis by angiotensin-converting enzyme inhibition is modifiable

BACKGROUND

Proteinuria is associated with a progressive loss of renal function; we recently found that both intrarenal effects of proteinuria and the state of systemic nephrosis play an independent role in proteinuria-induced renal damage. Reduction of proteinuria is an important mechanism underlying the renoprotective effect of angiotensin-converting enzyme inhibition (ACEi). Both the reduction of proteinuria and the attenuation of the systemic state of nephrosis may be involved in the renoprotection by ACEi.

METHODS

This article entails a post hoc analysis of a previous study on the renoprotective effect of ACEi lisinopril in adriamycin nephrosis. It was attempted to modify therapeutic efficacy of ACEi by increasing lisinopril dose and by dietary sodium restriction, respectively. In this analysis, we aimed to delineate the contribution of proteinuria reduction and the reduction of other intermediate parameters such as hyperlipidemia and blood pressure on the protection against focal glomerulosclerosis (FGS).

RESULTS

We found that in adriamycin nephrosis, ACEi significantly reduced proteinuria, lipids, and blood pressure and provided protection against FGS. Treatment modification by increasing the lisinopril dose resulted in a further reduction of FGS without significant effects on intermediate parameters (proteinuria, hyperlipidemia, and blood pressure), whereas surprisingly, treatment modification by sodium restriction resulted in a further attenuation of intermediate parameters, without additional protection against FGS.

CONCLUSIONS

The renoprotective benefit of an obtained attenuation of intermediate parameters is modified by other factors. Further optimization of renoprotective therapy requires identification of such factors and explicit consideration of therapeutic efficacy on intermediate parameters as well as hard end points.

Chronic aminoguanidine attenuates renal dysfunction and injury in aging rats

We have previously shown that aging is associated with increased lipid peroxidation, reductions in renal function, and increased glomerular sclerosis. The mechanism(s) responsible for these age-related changes are not clear. The purpose of the present studies was to determine if there was an increase in inducible nitric oxide synthase (iNOS) with aging, and if so, whether inhibition of iNOS would prevent aging injury by preventing free radical-mediated lipid peroxidation. iNOS protein expression in the kidney increased by approximately 90% by 24 months. Inhibition of iNOS by aminoguanidine (0.1% in drinking water) for 9 months, beginning at 13 months of age, reduced blood pressure, improved glomerular filtration rate by 70%, and renal plasma flow by 40%, whereas glomerular sclerosis was considerably reduced. Renal F2-isoprostanes and malondialdehyde levels, markers of oxidative stress and lipid peroxidation, were not reduced by aminoguanidine. Aminoguanidine also did not attenuate immunostaining for advanced glycosylation end products (AGE) in the kidneys. These findings suggest that aminoguanidine attenuates aging renal dysfunction by inhibiting a pathophysiologic function of iNOS that is independent of free radical-mediated lipid peroxidation or significant effects on AGE deposition.

Angiotensin II receptor blockade limits kidney injury in two-kidney, one-clip Goldblatt hypertensive rats with special reference to phenotypic changes

Recent evidence indicates that tubulointerstitial injury plays an important role in hypertensive kidney injury and that phenotypic changes contribute to this pathology. Moreover, angiotensin II is known to be actively involved in the pathogenesis of progressive kidney injury induced by hypertension. The present study was undertaken to see the effect of a newly developed angiotensin II type I receptor (AT1 receptor) antagonist on hypertension-induced kidney injury and to determine the contribution of phenotypic changes to morphologic alterations. Two-kidney, one-clip (2K1C), Goldblatt hypertensive rats (n = 27) were made by clipping the left renal artery. These animals were orally administered 57G709 (a selective non-peptide AT1 receptor antagonist)(10 mg/kg/day), captopril (20 mg/kg/day), or vehicle alone for 23 days beginning 4 weeks after clipping. In the non-clipped kidney of vehicle-treated 2K1 C rats, marked tubulointerstitial injury as well as glomerular sclerosis and/or hyalinosis was found in association with phenotypic changes, as shown by the neoexpression of vimentin in periglomeruli, perivascular walls, distal tubuli, and injured interstitium. Renin expression was markedly suppressed in the non-clipped kidneys of vehicle-treated 2K1C rats as compared with renin expression in normotensive control kidneys of sham-operated rats. Both 57G709 and captopril markedly ameliorated hypertensive kidney injury as reflected by the glomerular sclerosing index and by the tubulointerstitial index as determined by the point-counting method, and this improvement was accompanied by a significant decrease in blood pressure, urinary protein excretion, kidney/body weight ratio, and heart/body weight ratio. In addition, the vimentin neoexpression mentioned above was also suppressed with an inhibition of angiotensin II. These results suggest that in 2K1C Goldblatt hypertensive kidney injury, the AT1 receptor antagonist 57G709 exerts a potent renal protective effect associated with the inhibition of phenotypic changes.

ACE-I vs angiotensin II receptor antagonists: prevention of renal injury in chronic rat models

There is now abundant evidence that treatment with angiotensin-converting enzyme inhibitors (ACE-I) ameliorates the progression of chronic renal disease. Attention has therefore focused on the role of the renin angiotensin-aldosterone (RAA) system in mediating the development of progressive glomerulosclerosis and angiotensin II (Ang II) has been implicated in several processes thought to be important in the pathogenesis of this entity. Conversely, ACE is also known to catalyse the breakdown of bradykinin. Thus, ACE-I treatment results in elevated bradykinin levels which may cause selective efferent arteriolar dilatation, suggesting an alternative explanation for the beneficial effects of this class of drugs in chronic renal disease. The development of specific angiotensin type 1 receptor antagonists (AT1RA) has provided a means of testing the relative importance of these two mechanisms. In addition, AT1RAs differ from ACE-I in their effect on the RAA system in other aspects which may represent therapeutic advantages. This paper reviews studies which have compared ACE-I and AT1RAs in several rat models of chronic renal disease. Most have found similar beneficial effects including amelioration of proteinuria and glomerulosclerosis, which suggests that the effects of ACE-I are due to a reduction in Ang II activity and not due to increased levels of bradykinin. One long-term study has suggested greater renal protection with candesartan than with enalapril. However, conclusions as regards the relative efficacy of these two groups of agents in ameliorating the progression of chronic renal disease await the results of further long-term studies.

Effects of polyunsaturated fatty acids on rat glomerulosclerosis induced by hypercholesterolaemic diet

Association between lipids and renal disease has been reported recently. Its pathogenic mechanisms remain unknown. The aims of this study were to establish: (1) if a cholesterol-rich diet, alone or associated with nephrectomy, produces nephropathy; and (2) if a treatment with omega-3 polyunsaturated fatty acids (PUFA) reduces glomerulosclerotic lesions. Sixty Sprague-Dawley rats were randomized in two different groups: (A) sham operated rats and (B) uninephrectomized rats. Rats in both groups were divided into three subgroups (A1-3, B1-3) according to the diet they were fed: normal chow diet, cholesterol-rich diet (4.5%) or cholesterol-rich diet supplemented with omega-3 PUFA. Twenty weeks later, serum creatinine, creatinine clearance, serum cholesterol, triglycerides, albumin, proteinuria, mesangial cell score and focal glomerulosclerosis were assessed. Results showed that a cholesterol-rich diet significantly increased serum cholesterol, proteinuria and glomerular lesions and decreased creatinine clearance, especially in nephrectomized rats. Glomerular lesions, serum cholesterol and proteinuria ameliorated when cholesterol-rich diet was supplemented with PUFA. Hypertension was noticed only in nephrectomized rats following a normal chow diet. Simple correlation analysis showed that glomerulosclerosis correlated with renal weight, blood creatinine, cholesterol and proteinuria. In spite of some significant differences in urinary prostaglandins, no correlation with glomerular lesions was found. Multiple logistic regression analysis showed that cholesterol and proteinuria were independent risk factors for induction of glomerular sclerosis. In conclusion, a diet rich in cholesterol induces glomerulosclerosis, especially if it is associated with unilateral nephrectomy. Omega-3 PUFA administration reduces serum cholesterol, proteinuria and glomerular injury.

Nitroflurbiprofen, a new nonsteroidal anti-inflammatory, ameliorates structural injury in the remnant kidney

Cyclooxygenase derivatives and nitric oxide (NO) may influence the pathogenesis of progressive nephropathies. We investigated the effect of nitroflurbiprofen (NOF), a NO-releasing nonsteroidal anti-inflammatory drug (NSAID) without gastrointestinal toxicity, in rats with 5/6 ablation (NX). The following four groups were studied: Sham, sham-operated rats; Sham + NOF, Sham receiving oral NOF two times daily; NX, rats subjected to NX; and NX + NOF, NX receiving NOF. NOF was barely detected in plasma but released the parent compound flurbiprofen. At 30 days, glomerular hydraulic pressure (PGC) was 76 +/- 3 mmHg in NX (52 +/- 1 in Sham, P < 0.05). NOF slightly reduced PGC to 69 +/- 2 mmHg in NX + NOF (P > 0.05 vs. NX). Glomerular volumes behaved similarly. At 60 days, tail cuff pressure was 152 +/- 6 mmHg, glomerulosclerosis index was 22.1 +/- 9.5, and interstitial fractional area was 9.9 +/- 1.2% in NX. NOF reduced these parameters to 137 +/- 4 mmHg, 3.5 +/- 0.7, and 6.4 +/- 0.8%, respectively (P < 0.05), without causing growth stunting or anemia. These beneficial effects could not be ascribed to NO donation and may reflect cyclooxygenase inhibition. This is the first evidence that chronic NSAID treatment may ameliorate progressive nephropathies.

Combined effects of an angiotensin converting enzyme inhibitor and a calcium antagonist on renal injury

BACKGROUND

Angiotensin converting enzyme inhibitors have uniformly been shown to prevent the development both of proteinuria and of glomerulosclerosis in rats with a remnant kidney. Conversely, dihydropyridine calcium antagonists (DCA) have failed to demonstrate such a benefit in spite of causing an equivalent reduction in blood pressure.

OBJECTIVE

To test the hypothesis that concomitant administration of an angiotensin converting enzyme inhibitor and a DCA would lead to a smaller increase both in proteinuria and in glomerulosclerosis relative to that caused by administration of a DCA alone at similar levels of blood pressure.

METHODS

Experiments were carried out using Sprague-Dawley rats that had been subjected to five-sixths renal ablation. Animals were allocated randomly to one of four groups: control (no treatment), amlodipine (A rats), benazepril (B rats), or a combination of benazepril and amlodipine (B + A rats). We implanted intraperitoneal sensors for telemetric monitoring of the animal's blood pressure. Other parameters measured at baseline included proteinuria and inulin clearance. After approximately 7 weeks all of the parameters were remeasured and animals killed for morphologic assessment of the kidney.

RESULTS

The B + A rats had lower levels of proteinuria than did the rats in group A (21 +/- 12 mg/day for B + A rats versus 59 +/- 24 mg/day for A rats, P < 0.05). The degree of glomerulosclerosis in the B + A rats was also reduced markedly compared with that in A rats (12 +/- 4% for B + A rats versus 43 +/- 12% for A rats, P < 0.05). Moreover, the results on proteinuria and glomerulosclerosis of B + A rats were similar to those for B rats. These differences could not be explained totally in terms of differences in blood pressure control (144 +/- 12 mmHg in A rats versus 132 +/- 13 mmHg in B + A rats, NS).

CONCLUSION

The results were consistent with the observation that a combination of benzepril and amlodipine provides additional protection against renal injury compared with that provided by amlodipine alone. The mechanism for this benefit is not known.

Preventive effect of iganidipine on renal and cerebral injuries in salt-induced hypertension

Iganidipine, a new water-soluble calcium antagonist, was administered at a nonhypotensive dose (NHD) of 0.3 mg/kg/day, a moderate-hypotensive dose (MHD) of 1.0 mg/kg/day, and a sustained-hypotensive dose (SHD) of 3.0 mg/kg/day to Dahl salt-sensitive (Dahl-S) rats fed a high-salt diet for 8 weeks. The effects on survival, and on renal and cerebral injuries, were then examined. Iganidipine completely prevented hypertensive death at the SHD and tended to increase the survival at the NHD and MHD. Iganidipine reduced glomerulosclerosis and renal arterial and tubular injuries in a dose-dependent manner. Iganidipine at the SHD, but not NHD or MHD, improved plasma creatinine, serum urea nitrogen, and glomerular filtration rate. Iganidipine at all doses examined increased the urinary prostaglandin (PG) I2 and PGE2, but not PGF2alpha or thromboxane B2, and decreased plasma angiotensin II (AII) level and renin activity. The renal glomerular, tubular, and arterial injuries were significantly correlated with blood pressure (r = 0.56 to 0.80) and plasma AII level (r = 0.50 to 0.71) but not with urinary prostanoids. Iganidipine also reduced the incidence of cerebral infarction. The infarction area was slightly and significantly correlated with urinary PGI2 (r = 0.42) and PGE2 (r = 0.41) but not with blood pressure or plasma AII. In conclusion, iganidipine prevented renal and cerebral injuries in Dahl-S rats. In addition to the reduced blood pressure, the reduction of plasma AII and the increase of vasodilatory prostanoids may also partially contribute to the renal and cerebral protective effects of iganidipine.

Plasmapheresis for prevention of recurrent focal segmental glomerulosclerosis of kidney allograft in adult recipients

Nephrotic syndrome due to focal segmental glomerulosclerosis (FGS) frequently recurs even after renal transplantation and may cause renal allograft failure. From January 1983 though April 1995, 11 adult recipients with primary FGS received 11 kidney transplants at our institution, and 3 of them were treated with pretransplant plasma exchange (PE). Other patients did not receive any preoperative PE, and 4 patients lost their grafts due to recurrent FGS (50%). PE was completed 3 times before the transplantation to prevent posttransplant recurrence of FGS. Two recipients did not have any proteinuria or graft dysfunction without posttransplant PE. One patient had mild proteinuria immediately after transplantation, and histological examination showed recurrent FGS. The patient has been undergoing PE once a month (2 years posttransplant). Her renal function is excellent (sCr 1.2 mg/dl), and her FGS is being well controlled by PE. PE seems to be effective for the prevention of the recurrence of FGS following renal transplantation.

Dietary antioxidant inhibits lipoprotein oxidation and renal injury in experimental focal segmental glomerulosclerosis

Lipid peroxidation may be involved in the pathogenesis of focal segmental glomerulosclerosis (FSGS). In the present study we examined whether lipid-soluble antioxidants, probucol and vitamin E, could inhibit renal injury in rats with chronic puromycin aminonucleoside (PA) nephrosis and dietary hypercholesterolemia by protecting lipoproteins from oxidation. Male Sprague-Dawley rats received six intraperitoneal injections of PA over a 10 week period and were fed a high cholesterol (HC) diet (PA-HC) or the same diet supplemented with either 1% probucol or vitamin E (100 IU/kg) for 32 weeks. For comparison, a group of rats received PA injections and a normal diet (PA-normal) with or without probucol or vitamin E. Another group rats received saline injections instead of PA and were fed a HC diet (Sal-HC) with or without probucol or vitamin E. At the end of the experiment, proteinuria, FSGS and tubulointerstitial lesions were present in the untreated rats with PA-HC or PA-normal. The magnitude of these lesions was significantly greater in the PA-HC rats than the PA-normal. In contrast to the PA-HC group with hypercholesterolemia, the PA-normal group did not show hypercholesterolemia from week 16 onwards. The rats with PA-HC alone showed significantly higher renal cortical malondialdehyde (MDA) levels and greater susceptibility of plasma very low density lipoprotein (VLDL) + low density lipoprotein (LDL) to the copper-mediated oxidation than the rats with PA-normal or Sal-HC alone. The administration of probucol or vitamin E in the rats with PA-HC significantly reduced the susceptibility of plasma VLDL + LDL to in vitro oxidation, renal cortical MDA level, proteinuria, mesangial volume density and magnitude of FSGS and interstitial lesions. Immunohistochemical staining of renal tissue showed focal segmental distribution of oxidized LDL (Ox-LDL) in the glomeruli of rats with PA-HC. Administration of probucol or vitamin E reduced the intensity of Ox-LDL staining. The staining with ED1 demonstrated that infiltrating glomerular macrophages were significantly more prevalent in the untreated rats with PA-HC than PA-normal or Sal-HC. Treatment with probucol or vitamin E significantly reduced the number of glomerular macrophages in the rats with PA-HC. These results suggest that alimentary hypercholesterolemia aggravates the renal damage in association with increased renal lipid peroxides in chronic PA nephrosis, and that dietary probucol or vitamin E attenuates renal injury in rats with PA-HC possibly by making lipoproteins resistant to oxidation and by inhibiting intraglomerular macrophage infiltration.