Effect of the angiotensin-converting-enzyme inhibitor benazepril on the progression of chronic renal insufficiency. The Angiotensin-Converting-Enzyme Inhibition in Progressive Renal Insufficiency Study Group

Ramipril prolongs life and is cost effective in chronic proteinuric nephropathies

BACKGROUND

Our objectives were to predict the long-term cost and efficacy of the angiotensin-converting enzyme, ramipril, in patients with nondiabetic chronic nephropathies.

METHODS

The time to end-stage renal disease (ESRD) was predicted by two different models based on the rate of glomerular filtration rate decline (DeltaGFR) and incidence of ESRD (events) measured during the Ramipril Efficacy in Nephropathy Trial in 117 and 166 patients, respectively, randomized to comparable blood pressure control with ramipril or conventional therapy. Direct medical costs of conservative and renal replacement therapy were estimated by a payer perspective, and cases more and less favorable to ramipril were computed by a sensitivity analysis. The study took place at the Clinical Research Center for Rare Diseases, "Aldo & Cele Daccò," Bergamo, Italy. Patients included those with chronic, nondiabetic nephropathies and persistent urinary protein excretion rate >/=3 g/24 h. Time to ESRD, survival, and direct costs of conservative and renal replacement therapy are discussed.

RESULTS

Both in the DeltaGFR-based or events-based models, ramipril delayed progression to ESRD and prolonged patient survival by 1.5 to 2.2 and 1.2 to 1.4 years, respectively, and saved $16,605 to $23,894 lifetime and $2, 422 to $4203 yearly direct costs per patient. Even in the less favorable hypotheses, ramipril allowed lifetime and yearly cost savings that exceeded 10 to 11 and 20 to 40 times, respectively, the additional costs related to prolonged survival.

CONCLUSIONS

In our study population, ramipril prolongs life while saving money because of its beneficial effect on the course of nondiabetic chronic nephropathies.

Research on renal endothelin in proteinuric nephropathies dictates novel strategies to prevent progression

Proteinuria is one of the major risk factors for renal disease progression in patients with chronic nephropathies. Studies in disease models have helped to delineate mechanisms leading to renal structural damage as a result of persistent dysfunction of the glomerular barrier to proteins, even when the primary immune or non-immune insult to the kidney has ceased. From these preclinical studies, a role for endothelin in proteinuric chronic renal diseases has been suggested, thus providing the rationale for novel therapeutic approaches with endothelin receptor antagonists to maximize renoprotection so far achieved with blockade of the renin-angiotensin system by angiotensin-converting enzyme inhibition or angiotensin II receptor antagonism. Trials are needed to explore this potential area of clinical interest.

Treatment of hypertension in patients with diabetes: lessons from recent trials

Hypertension plays a critical role in causing a high rate of cardiovascular events in patients with diabetes mellitus. Large trials show that lowering blood pressure in the patient with diabetes who has hypertension has profoundly favorable effects. This review discusses recent trials to answer the question of how low patients' blood pressure should go and which agents should be used to achieve this goal. The National Institutes of Health's guidelines, published in the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, call for a blood pressure goal of <130/85 mmHg in patients with diabetes. Based on data from the recent trials, an even lower blood pressure of <130/80 mmHg in patients with diabetes and hypertension appears to be appropriate. Observational studies show that the lowest cardiovascular event rate is observed in patients with diabetes whose systolic blood pressure is <120 mmHg. Thus, goal blood pressure in patients with diabetes who have hypertension may need to be revised lower, to <120/80 mmHg. In patients with overt proteinuria of 1 g/d or more, mean arterial pressure of <92 mmHg is recommended. Available evidence justifies the use of angiotensin-converting enzyme (ACE) inhibitors as first-line agents and angiotensin receptor blockers in those patients who are intolerant to ACE inhibitors. Because the blood pressure goal is lower in patients with diabetes who are hypertensive, these patients require the use of multiple agents. Diuretics or long-acting calcium channel blockers are logical second choices because of their synergistic blood pressure reduction effect observed with ACE inhibitors. Alpha-blockers should be used with caution, however. In patients with renal disease, loop diuretics may be required to reduce sodium and volume overload and to improve blood pressure control.

Cost effectiveness of ramipril in patients with non-diabetic nephropathy and hypertension: economic evaluation of Ramipril Efficacy in Nephropathy (REIN) Study for Germany from the perspective of statutory health insurance

BACKGROUND

In the Ramipril Efficacy In Nephropathy (REIN) trial, ramipril significantly lowered the rate of reaching the combined end-point of doubling of baseline serum creatinine levels or end-stage renal failure (ESRF).

OBJECTIVE

To determine the additional cost per patient-year of chronic (long term) dialysis avoided (PYCDA) when the ACE inhibitor, ramipril, was added to conventional treatment of patients with non-diabetic nephropathy and hypertension.

STUDY PERSPECTIVE

Statutory Health Insurance (SHI) provider in Germany.

DESIGN AND SETTING

Data from the REIN Study were used in a cost-effectiveness analysis (CEA). A modelling approach was used, which was based on secondary analysis of published data, and costs were those incurred by the SHI provider (i.e. SHI expenses). In the base-case analysis, average case-related SHI expenses were applied and PYCDA were quantified using the cumulative incidence of ESRF as observed in the REIN trial.

MAIN OUTCOME MEASURES AND RESULTS

The incremental cost-effectiveness ratios (ICERs) of ramipril varied between about -76,700 deutschmarks (DM) and -DM81,900 per PYCDA (DM 1 approximately equals 0.55 US dollars; 1999 values), according to the treatment periods of 1 year and 3 years, respectively. In the sensitivity,analysis, the robustness of the model and its results were shown when the extent of influence of different model variables on the base-case results was investigated. First, probabilities of ESRF and PYCDA were estimated according to the Weibull method. Second, the influence of the model variables on the target variable was quantified using a deterministic model. Third, the dependency of the target variable (ICER) on random variables was described in a simulation. The cost for chronic dialysis had by far the greatest impact on the target variable, which was 28 times greater than the impact of clinical effectiveness of ramipril, i.e. the number of PYCDA. There were net savings per PYCDA with ramipril treatment after 1, 2 and 3 years: 95% of the 10,000 simulation steps resulted in savings of between DM69 500 and D94,600 per PYCDA after 3 years.

CONCLUSIONS

Results from this evaluation show that ramipril offers enormous savings from the perspective of the SHI provider (third-party payer) in Germany when added to the conventional treatment of patients with non-diabetic nephropathy and hypertension.

Angiotensin II mediated signal transduction. Important role of tyrosine kinases

It has been 100 years since the discovery of renin by Bergman and Tigerstedt. Since then, numerous studies have advanced our understanding of the renin-angiotensin system. A remarkable aspect was the discovery that angiotensin II (AngII) is the central product of the renin-angiotensin system and that this octapeptide induces multiple physiological responses in different cell types. In addition to its well known vasoconstrictive effects, growing evidence supports the notion that AngII may play a central role not only in hypertension, but also in cardiovascular and renal diseases. Binding of AngII to the seven-transmembrane angiotensin II type 1 receptor is responsible for nearly all of the physiological actions of AngII. Recent studies underscore the new concept that activation of intracellular second messengers by AngII requires tyrosine phosphorylation. An increasing number of tyrosine kinases have been shown to be activated by AngII, including the Src kinase family, the focal adhesion kinase family, the Janus kinases and receptor tyrosine kinases. These actions of AngII contribute to the pathophysiology of cardiac hypertrophy and remodeling, vascular thickening, heart failure and atherosclerosis. In this review, we discuss the important role of tyrosine kinases in AngII-mediated signal transduction. Understanding the importance of tyrosine phosphorylation in AngII-stimulated signaling events may contribute to new therapies for cardiovascular and renal diseases.

Pretreatment blood pressure reliably predicts progression of chronic nephropathies. GISEN Group

BACKGROUND

Random, nontimed blood pressure (BP) measurements in the outpatient clinic may fail to provide reliable information on actual daily BP control in renal patients on chronic antihypertensive therapy.

METHODS

In a cohort of 163 patients with proteinuric chronic nephropathies followed prospectively with repeated BP and glomerular filtration rate (GFR) measurements, we compared baseline and follow-up pretreatment, morning ("trough," measured by standard procedures, and "0 minutes," measured by an automatic device) and post-treatment (120 minutes) measurements, with BP monitored up to 600 minutes after treatment administration. We then evaluated which BP value most reliably predicted GFR decline (delta GFR) and progression to end-stage renal failure (ESRF) over a median (interquartile range) follow-up of 20 (9 to 25) months.

RESULTS

GFR decline was more reliably predicted by systolic as compared with diastolic BP and by pretreatment as compared to post-treatment BP, regardless of the timing and method of measurement, respectively. In particular, at the 120-minute baseline and follow-up measurements, systolic BP had no predictive value in patients with less severe renal insufficiency and baseline diastolic BP, regardless of the level of renal dysfunction. The BP predictive value was remarkably higher in ramipril than in conventionally treated patients. All follow-up-but no baseline-measurements reliably predicted the risk of ESRF in the entire study group.

CONCLUSIONS

In patients with progressive chronic nephropathies, systolic BP and pretreatment morning BP measurements are the most reliable predictors of disease outcome and may serve to guide antihypertensive therapy in routine clinical activities and in prospective controlled trials, particularly in patients on angiotensin-converting enzyme inhibitor therapy. Reliability and relevance of single measurements taken at different times after treatment administration are questionable.

Diabetic neuropathy--a continuing enigma

In this article we will review the clinical signs and symptoms of diabetic somatic polyneuropathy (DPN), its prevalence and clinical management. Staging and classification of DPN will be exemplified by various staging paradigms of varied sophistication. The results of therapeutic clinical trials will be summarized. The pathogenesis of diabetic neuropathy reviews an extremely complex issue that is still not fully understood. Various recent advances in the understanding of the disease will be discussed, particularly with respect to the differences between neuropathy in the two major types of diabetes. The neuropathology and natural history of diabetic neuropathy will be discussed pointing out the heterogeneities of the disease. Finally, the various prospective therapeutic avenues will be dealt with and discussed.

ACE inhibition or angiotensin receptor blockade: impact on potassium in renal failure. VAL-K Study Group

BACKGROUND

Inhibition of the renin-angiotensin system is known to raise serum potassium [K(+)] levels in patients with renal insufficiency or diabetes. No study has evaluated the comparative effects of an angiotensin-converting enzyme (ACE) inhibitor versus an angiotensin receptor blocker (ARB) on the changes in serum [K(+)] in people with renal insufficiency.

METHODS

The study was a multicenter, randomized, double crossover design, with each period lasting one month. A total of 35 people (21 males and 14 females, 19 African Americans and 16 Caucasian) participated, with the mean age being 56 +/- 2 years. Mean baseline serum [K(+)] was 4.4 +/- 0.1 mEq/L. The glomerular filtration rate (GFR) was 65 +/- 5 mL/min/1.73 m(2), and blood pressure was 150 +/- 2/88 +/- 1 mm Hg. The main outcome measure was the difference from baseline in the level of serum [K+], plasma aldosterone, and GFR following the initial and crossover periods.

RESULTS

For the total group, serum [K(+)] changes were not significantly different between the lisinopril or valsartan treatments. The subgroup with GFR values of < or = 60 mL/min/1.73 m(2) who received lisinopril demonstrated significant increases in serum [K(+)] of 0.28 mEq/L above the mean baseline of 4.6 mEq/L (P = 0.04). This increase in serum [K(+)] was also accompanied by a decrease in plasma aldosterone (P = 0.003). Relative to the total group, the change in serum [K(+)] from baseline to post-treatment in the lisinopril group was higher among those with GFR values of < or = 60 mL/min/1.73 m(2). The lower GFR group taking valsartan, however, demonstrated a smaller rise in serum [K(+)], 0.12 mEq/L above baseline (P = 0.1), a 43% lower value when compared with the change in those who received lisinopril. This blunted rise in [K(+)] in people taking valsartan was not associated with a significant decrease in plasma aldosterone (P = 0.14).

CONCLUSIONS

In the presence of renal insufficiency, the ARB valsartan did not raise serum [K(+)] to the same degree as the ACE inhibitor lisinopril. This differential effect on serum [K(+)] is related to a relatively smaller reduction in plasma aldosterone by the ARB and is not related to changes in GFR. This study provides evidence that increases in serum [K(+)] are less likely with ARB therapy compared with ACE inhibitor therapy in people with renal insufficiency.

The treatment of primary focal segmental glomerulosclerosis

Nephrotic patients with primary focal segmental glomerulosclerosis (FSGS) have a poor prognosis with 50% progressing to end stage renal disease (ESRD) over 3 to 8 years. The achievement of a remission in proteinuria has been associated with a significantly improved renal survival as compared to those patients not attaining a remission. Unfortunately, spontaneous remissions are rare in FSGS, and the response to therapy has historically been poor. Recent experience with more aggressive immunosuppressive therapy has lead to an increase in the remission rate for FSGS patients and given rise to optimism in the treatment of this glomerulopathy.

Pauci-immune renal vasculitis: natural history, prognostic factors, and impact of therapy

The purpose of this study is to describe the clinical presentation and natural history of pauci-immune renal vasculitis and determine whether particular presenting features or administered therapies predict outcome. We reviewed our experience since 1984 with such vasculitides, and 94 cases of pauci-immune vasculitis were identified. Presenting features were as follows: men, 63%; mean age at biopsy, 59 years; and mean serum creatinine level, 5.0 mg/dL. Patients with no extrarenal involvement had a tendency to present with a greater serum creatinine level. Since the antineutrophil cytoplasmic autoantibody (ANCA) assay became available, 77% of the patients tested were ANCA positive. In terms of natural history, 27 patients required dialysis immediately, there were 22 renal relapses, 28 patients progressed to dialysis, 10 patients died before requiring dialysis, 19 patients were lost to follow-up, and 37 patients remain active, not on dialysis. Overall, half the patients recovered some renal function, one third remained stable, and one sixth deteriorated. Female sex and angiotensin-converting enzyme inhibitor use predicted favorable outcome (P < 0.05). Advanced age, male sex, respiratory tract involvement, and a greater relapse rate predicted unfavorable outcome (P < 0.05). The incidence of pauci-immune renal vasculitis appears to be increasing, likely related to the emergence of the ANCA assay. Attempts to classify patients based on existing schemes may result in delayed diagnosis and therapy, with subsequent poorer outcomes. Also, given the increased mortality of patients with respiratory tract involvement, we speculate that respiratory tract disease therapeutic and monitoring regimens are ineffective. In general, we conclude that pauci-immune renal vasculitis is a heterogeneous disorder with an unfavorable prognosis.

Transforming growth factor-beta in renal disease

An extensive number of animal and clinical studies indicate that transforming growth factor-beta (TGF-beta s) play an important role in inflammatory and fibrotic diseases, including renal fibrosis. Recent mouse models harboring genetically engineered alterations in TGF-beta pathways reveal complicated mechanisms of regulation of TGF-beta activity in vivo. The purpose of this review is to present recent advances relevant to our understanding of the TGF-beta-signaling system in renal physiology and pathophysiology.

Angiotensin-converting enzyme gene polymorphism determines the antiproteinuric and systemic hemodynamic effect of enalapril in patients with proteinuric renal disease. Austrian Study Group of the Effects of Enalapril Treatment in Proteinuric Renal Disease

Angiotensin-converting enzyme (ACE) inhibitors are known to reduce blood pressure and proteinuria in a variety of different glomerular diseases. Nonetheless, a marked interindividual difference in the efficacy of these agents exists. The activity of the ACE and therefore of the renin-angiotensin-aldosterone system (RAAS) has been shown to be under genetic influence. Patients with a deletion genotype at the intron 16 of the ACE gene have been shown to exhibit higher activity of plasmatic ACE when compared to patients with the insertion genotype. We therefore studied prospectively the hemodynamic and antiproteinuric effect of a 6-month therapy with enalapril in patients with biopsy-proven proteinuric glomerular diseases and the DD (n = 10) and ID/II (n = 26) genotype. Although patients with the DD genotype received a slightly higher dose of enalapril, blood pressure and proteinuria did not change significantly. However, both were significantly reduced in the II/ID group after 10 weeks and 6 months of therapy. Creatinine clearance decreased steadily in DD patients. In II/ID patients, creatinine clearance was reduced significantly after 10 weeks of therapy but increased again thereafter and the value at 6 months was again comparable to the one obtained in the DD patients. We conclude from our study that the ACE genotype influences the blood pressure-lowering and antiproteinuric effect of enalapril in patients with proteinuric glomerular disease.

The need to lower systolic blood pressure

Systolic hypertension is the most common form of hypertension, especially in individuals aged 60 years or older. Systolic hypertension is a reflection of decreasing compliance of large arteries and is a strong independent risk factor for all cardiovascular diseases. Despite proven benefits of therapy for systolic hypertension, only 25% of patients with this condition are adequately treated to attain target blood pressures. The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of high blood pressure (JNC VI) recommends the use of diuretics and long-acting dihydropyridine calcium channel blockers as first-line therapy for isolated systolic hypertension. Therapy is also guided by comorbid conditions where certain drugs may have additional benefits. The goal of therapy should be a graded reduction in blood pressure to less than 140/90 mm Hg with lower blood pressure targets in patients with coexistent diabetes or renal failure.

Epidemiology, diagnosis, and management of cardiac disease in chronic renal disease

There is an extremely high burden of cardiovascular disease (CVD) in patients with renal disease. Both traditional as well as uremia-related factors are contributory. Diagnosis of CVD has limitations in patients with renal disease, and suspicion for the presence of CVD needs to be high even in the absence of classic symptoms. Prevention and management of CVD is similar to the general population but important differences need to be noted.

Prospective analysis of the value of 24-hour ambulatory blood pressure on renal function after kidney transplantation

BACKGROUND

No prospective study has been performed to determine the prognostic value of 24-hr ambulatory blood pressure (24-hr ABP) versus casual blood pressure (CBP) in patients after kidney transplantation. We have addressed this issue by analyzing renal graft function in patients for the first 5 years after transplantation.

METHODS

The 24-hr ABP (SpaceLabs 90207) was monitored 6 and 18 months after transplantation in 46 renal transplant recipients without any acute episodes of rejection. Combined study endpoints were death of patients, need for dialysis, second transplantation, and doubling of serum creatinine.

RESULTS

Six months after transplantation systolic and diastolic 24-hr ABP correlated with serum creatinine (r=0.41, P=0.005 and r=0.37, P<0.01, respectively) although CBP did not. Divided into tertiles according to average 24-hr ABP (lower tertile: < or =91 mmHg; middle tertile: 92-97 mmHg; upper tertile: > or =98 mmHg) serum creatinine significantly differed between the three groups (1.26 +/- 0.38 vs. 1.32 +/- 0.25 vs. 1.65 +/- 0.39 mg/dl, respectively; analysis of variance, P< 0.01). Confounding factors of renal function such as age, body weight, cold and warm ischemic time, cytomegaly virus status, methylprednisone and cyclosporine dosages, cyclosporine concentrations, as well as concomitant antihypertensive medication did not differ among the three groups. In the long-term follow-up (5 years), combined endpoints were reached in 3 of 15 of the lower tertile group, in 3 of 15 of the median tertile group, and in 8 of 16 of the upper tertile group (log-rank test, P<0.01). No relation to long-term out come was found when patients were stratified according to their CBP.

CONCLUSION

In our small but homogenous study cohort 24-hr ABP was more closely related to renal function in patients after transplantation than CBP suggesting that 24-hr ABP is superior for evaluation of hypertension-related renal graft dysfunction.

Smoking--a renal risk factor

One of the most important tasks of clinical and experimental nephrology is to identify the risk factors of progression of renal failure. A major renal risk factor which has not been sufficiently acknowledged despite increasing evidence is cigarette smoking. Diabetologists were the first to recognize the adverse effects of smoking on the kidney: both in type 1 and in type 2 diabetes smoking (i) increases the risk of development of nephropathy and (ii) nearly doubles the rate of progression to end-stage renal failure. Until recently it was not known whether smoking also increases the risk to progress to end-stage renal failure in patients with primary renal disease. A retrospective multicenter European case-control study showed that smoking is an independent risk factor for end-stage renal failure in patients with inflammatory and noninflammatory renal disease, i.e. IgA glomerulonephritis and polycystic kidney disease. The pathogenesis of the smoking-related renal damage is largely unknown. The intermittent increase in blood pressure during smoking seems to play a major role in causing renal damage, but further potential pathomechanisms are presumably also operative. Smoking as a renal risk factor is of great interest to diabetologists as well as nephrologists, but unfortunately so far this information has had little impact on patient management. The present article reviews the current knowledge about the renal risks of smoking and discusses the potential mechanisms of smoking-mediated renal injury.

Effects of angiotensin-converting enzyme inhibitor, angiotensin II receptor antagonist and calcium antagonist on urinary podocytes in patients with IgA nephropathy

The urinary podocyte is postulated to be a marker for estimation of the severity of active glomerular injury and a predictor of disease progression in children with glomerulonephritis. Non-dihydropyridine calcium antagonist, including verapamil, reduce proteinuria to an extent similar to that of the angiotensin-converting enzyme inhibitor (ACEI), including trandolapril, but to a greater extent than other antihypertensives. Angiotensin (Ang) II receptor antagonists, including candesartan cilexetil, show potent and long-term preventive effects against the progression of renal injury. The aim of the present study is to assess whether verapamil, trandolapril and candesartan cilexetil affect proteinuria and urinary podocytes in patients with IgA nephropathy. Thirty-two normotensive patients aged 18-54 years with biopsy-proven IgA nephropathy, nonnephrotic proteinuria (1-3 g/day), and normal renal function (creatinine clearance >80 ml/min) were studied. Twenty patients with diffuse mesangial proliferative glomerulonephritis (non-IgA PGN) and 20 healthy controls were also included in this study. The number of urinary podocytes in patients with advanced IgA nephropathy (n = 16) was significantly higher than that in patients with the disease in the mild stage (n = 16) (p < 0.01) or in patients with non-IgA PGN (p < 0.01). Urinary podocytes were not detected in healthy controls. The 32 patients with IgA nephropathy were randomly divided into four treatment groups: those treated with verapamil (120 mg/day, n = 8); those treated with trandolapril (2 mg/day, n = 8); those treated with candesartan cilexetil (8 mg/day, n = 8), and those given a placebo (n = 8). Treatment continued for 3 months. Antiproteinuric response in the trandolapril group was similar to that in the candesartan cilexetil group (-38 vs. -40%). The action of trandolapril or candesartan cilexetil was greater than that of verapamil (p < 0.01). Reduction in the number of urinary podocytes from baseline was significantly greater in patients treated with trandolapril or candesartan cilexetil than in patients treated with verapamil (p < 0.01). However, there was no difference between patients treated with trandolapril and those treated with candesartan cilexetil. Proteinuria and urinary podocytes were unaffected in the placebo group. These data suggest that urinary podocytes may be a marker of disease activity in adult patients with IgA nephropathy and that trandolapril and candesartan cilexetil are more effective than verapamil in reducing the number of podocytes.

Reducing cardiovascular morbidity and mortality from hypertension in end-stage renal disease

Hypertension typically worsens with declining renal function, and is an almost universal feature of end-stage renal disease. Treating hypertension clearly reduces the likelihood of cardiovascular disease in nonrenal populations, with greater absolute benefit in those who have greater severity of underlying cardiovascular disease. Patients with chronic renal diseases are at enormous cardiovascular risk. Although our approach to hypertension in patients with early renal insufficiency has become more aggressive, the rationale has switched over the past decade from cardiovascular risk reduction to slowing the loss of renal function. Reliance on observational studies, especially using mortality as the outcome, has not allowed a consistent, rational approach to the treatment of hypertension in dialysis patients.

Amlodipine is comparable to angiotensin-converting enzyme inhibitor for long-term renoprotection in hypertensive patients with renal dysfunction: a one-year, prospective, randomized study

Unlike angiotensin converting enzyme inhibitors (ACEI), few long-term studies have shown calcium antagonists to retard the progression of renal dysfunction. Our aim was to prospectively compare the effects of amlodipine and ACEI (enalapril) on renal function in hypertensive patients with renal impairment due to chronic glomerulonephritis and essential hypertension. A total of 72 hypertensive patients with serum creatinine (Cr) > 1.5 mg/dL were randomly allocated to treatment with either drug. During a 1-year period, 33% of the patients treated with ACEI dropped out due to adverse events, whereas 9% of patients with amlodipine dropped out. Data of 28 patients were available for analysis of more than 1-year follow-up. Reductions in blood pressure were comparable between the amlodipine (from 165/101 to 138/81 mm Hg) and ACEI groups. Serum Cr increased from 2.1+/-0.8 (SD) to 2.6+/-1.0 mg/dL with amlodipine (n = 16), but the difference was equivalent to that with ACEI (n = 12). Creatinine clearance (Ccr) in the moderate dysfunction group (basal Cr, 1.5 to 2.0 mg/dL) changed from 36+/-10 to 33+/-11 mL/min (not significant) with amlodipine, and the change was similar to that noted with ACEI. Annual declines in Ccr with amlodipine (-3.7 mL/min/year) and ACEI (-2.6 mL/min/year) were comparable, and both tended to be smaller than the annual decline in glomerular filtration rate reported in the Modification of Diet in Renal Disease study (-6 mL/min/year). Serum potassium was increased significantly (P < .01), from 4.5+/-0.4 to 5.3+/-0.8 mEq/L, only in the ACEI group. This 1-year prospective study demonstrated the effect of amlodipine on renal function to be likely the same as that of ACEI. Furthermore, amlodipine was better tolerated than ACEI for hypertensive patients with renal dysfunction.

Renal growth factors: past, present and future

It is known that a series of mediators, so-called growth factors, are able to induce hypertrophy of the kidney in a patient after uninephrectomy. The first investigator who demonstrated this phenomenon was C. Sacerdotti, an Italian pathologist of Bizzozero's School in Turin, who published an important report in 1896. He attempted to explain how compensatory renal hypertrophy occurred and how this hypertrophy might be induced in a normal dog. Interestingly, he demonstrated that when the kidneys of a normal dog received a blood transfusion from uni- or binephrectomized dogs several mitoses appeared in the renal epithelium. These mitoses, expression of renal hypertrophy, were more evident in dogs receiving several blood transfusions for 6-7 days. He concluded that hypertrophy was induced by specific substances circulating in the blood of uni- or binephrectomized dogs. This hypothesis was in the next 100 years confirmed by the discovery of renal growth factors such as epidermal growth factor, insulin-like growth factor-1, hepatocyte growth factor, platelet-derived growth factor and others. The pathogenic role of these mediators is evident in the recovery of tubules after acute tubular necrosis and in the remnant glomeruli after glomerular damage. Today, attempts to use these growth factors for improving renal function in patients with acute tubular necrosis and to block their action in the progression of renal damage in chronic glomerulonephritides are under investigation. Future trends in these growth factors will be set by drug companies designing specific therapies such as gene therapy. In conclusion, the outstanding observation by Sacerdotti, over a century ago, remains an important step in nephrologic history for prognosis and therapy of renal diseases.

Therapeutic trials comparing angiotensin converting enzyme inhibitors and angiotensin II receptor blockers

Two independent pharmacologic methods of specifically interfering with the renin-angiotensin-aldosterone system have been brought to the marketplace: angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs). These agents have the potential not only to be very widely used for a broad variety of clinical indications but also to compete against each other as treatments for hypertension, heart failure, renal impairment, and other conditions. Many short-term comparative studies of these two classes of drugs have now been completed. Most have focused on surrogate endpoints, such as blood pressure, renal function, or cough. These studies have generally concluded that ARBs are better tolerated but that the two drug classes otherwise have similar efficacy. The largest clinical trial comparing ARBs and ACE inhibitors thus far completed, Evaluation of Losartan in the Elderly (ELITE 2), failed to confirm the results of a smaller study; it did not demonstrate a significant improvement in outcomes (death or hospitalization for heart failure) with an ARB used alone, despite better tolerability. Many longer-term outcome studies with survival endpoints are under way, but most will compare the combination against an ACE inhibitor alone. These studies will define the optimal use of these agents in medicine for decades to come.

The future of clinical trials in chronic renal disease: outcome of an NIH/FDA/Physician Specialist Conference. Evaluation of Clinical Trial Endpoints in Chronic Renal Disease Study Group

For people with chronic renal insufficiency, the therapeutic goal is to prevent progression to end-stage renal disease, a serious condition that can only be treated with dialysis and kidney transplantation. Although restriction of dietary protein slows the progression of renal disease somewhat, the principal treatment to slow chronic renal disease is appropriate reduction of blood pressure. Antihypertensive agents, particularly those that produce sustained, long-term reductions in proteinuria, such as angiotensin-converting enzyme inhibitors, not only decrease blood pressure but also preserve renal function. Clinical trials to evaluate these and other drug therapies in renal disease progression have used both "hard end points" (e.g., dialysis, transplantation, death) and intermediate end points of renal disease progression (e.g., doubling of serum creatinine concentration, reductions in proteinuria). Trials that have used hard end points typically recruited patients with advanced renal disease to demonstrate a difference in therapies within a period of 2 to 5 years. However, proteinuria reduction, along with a decrease in the time to doubling of serum creatinine in very early diabetic renal disease, could demonstrate an altered natural history of renal disease. Although hard end points are indicators of a drug's efficacy in reducing cardiovascular events or preserving renal function, they do not assess the impact of a treatment on altering the natural history of early renal disease. For clinical trials of people with all but the most advanced renal disease, use of intermediate end points of renal disease progression is the only practical option for assessment of treatment efficacy and effectiveness. Given the available data on proteinuria reduction and doubling of serum creatinine from clinical trials, these end points, taken together, appear to provide an acceptable means of assessing a treatment's impact on slowing renal disease progression.

Progress in blood pressure control in autosomal dominant polycystic kidney disease

Hypertension occurs commonly in autosomal dominant polycystic kidney disease (ADPKD) and is an important factor in the progression of the disease and cardiovascular mortality. The aim of this prospective 15-year study is to report the rate of blood pressure control and the potential effect of a 10-point education program developed by our center for ADPKD patients and their physicians. The patients' blood pressure treatment was managed by their primary care physicians. Three 5-year periods were analyzed in which similar rates of hypertension in patients with ADPKD were present (63% to 68%). In the first period (1985 to 1989), the rate of blood pressure control (<140/90 mm Hg) was 38% for 216 hypertensive patients with ADPKD. From 1990 to 1994, the percentage of blood pressure control increased to 55% in 194 hypertensive patients with ADPKD (P < 0.001 versus 1985 to 1989); and the level of blood pressure control increased to 64% in 181 hypertensive patients with ADPKD during 1995 to 1999 (P < 0.001 versus 1985 to 1989). Although this percentage of blood pressure control in patients with ADPKD remains suboptimal, it compares very favorably with the 27% estimated blood pressure control in patients with essential hypertension from 1991 to 1994 in the United States.

Renal tubulointerstitial fibrosis. New thoughts on its development and progression

Current investigation of the pathogenesis of tubulointerstitial injury indicates that both interstitial fibroblasts and renal tubular epithelial cells promote extracellular matrix accumulation. Moreover, two peptides--TGF-beta and angiotensin II--produced locally or delivered in the circulation, appear to play a central role in renal fibrosis. Pharmacologic amelioration of renal fibrosis may require methods directed at multiple factors involved in the fibrotic process, including angiotensin II, TGF-beta, and the proliferation and activation of interstitial fibroblasts.

Influence of the timing of initiating antihypertensive therapy in hypertensive rats with renal failure

The important contribution of hypertension to the progression of renal failure is well realized. However, it have been less discussed which drugs are suitable for the different stages of progressive renal failure. The present study examined the effects of timing of antihypertensive therapy using calcium channel blocker and angiotensin converting enzyme inhibitor in 5/6 nephrectomized spontaneously hypertensive rats (SHRs). Forty male 6 week old SHRs were divided into 5 groups (n=8 in each group), and they were placed on a high salt diet after 5/6 nephrectomy. Group 1, high salt diet without any drug. Group 2 received 0.2 mg/kg/day of amlodipine and group 3 received 0.2 mg/kg/day of enalapril mixed in the high salt diet from week 6 respectively. Similarly group 4 received the same doses of amlodipine, and group 5 received the same doses of enalapril from week 10. Each drug protected from increasing blood pressure in 4 groups, and no significant difference was observed between the effects of amlodipine and enalapril. Proteinuria was reduced with both drugs. In histopathological evaluation, glomerulosclerosis was controlled only in group 2, and arterio/olosclerosis was significantly suppressed in all treated groups except group 5. From these results, both amlodipine and enalapril are renal protective in early stage of renal failure with hypertension. However, in advanced stage of renal failure, amlodipine is superior in its renal protective effect.

Cellular and molecular mediators in common pathway mechanisms of chronic renal disease progression

Injury mechanisms activated by the hemodynamic adaptations to nephron loss are considered to represent a final common pathway that underlies the progressive nature of chronic renal disease. In this article, we review experimental evidence that the induction of cell adhesion molecule, cytokine and profibrotic growth factor gene expression and the resultant renal infiltration by inflammatory cells, especially macrophages, are important components of these common pathway mechanisms. Interventions aimed at inhibiting these mechanisms may offer new treatments for slowing or arresting the progression of chronic renal disease.

Characteristics of progressive renal disease

Virtually all renal diseases progress to terminal renal failure relatively independently of the initial disease. Arresting the rate of the deterioration of kidney failure has a great impact on reducing the number of patients reaching the stage of expensive renal replacement therapy. Understanding the mechanisms of the progression of kidney disease has greatly been improved during recent years. The nature of the progressive renal damage with various etiologies includes various well-known factors where hemodynamics, renin-angiotensin system (RAS) and progressive proteinuria play the central roles. Proteinuria has to be shown as an independent risk factor for renal disease progression. Also, disturbances in lipid metabolism as well as the later structural lesions contribute to the progression. Various modalities have been used for the prevention of progressive renal disease, e.g. low-protein diet, antihypertensive therapy, antifibrotic therapy. Many recent experimental and clinical studies have shown that besides the systemic blood pressure lowering effect, RAS blocking agents provide renal protective effects via direct, hemodynamic, and indirect, non-hemodynamic, pathways: (1) lowering intraglomerular capillary hydraulic pressure, and increasing the glomerular ultrafiltration coefficient; (2) lowering proteinuria; (3) lowering hyperlipidemia; (4) diminishing kidney growth; (5) diminishing infiltration of macrophages; (6) downregulation of proinflammatory cytokines. Therefore, RAS blocking agents are widely prescribed not only for antihypertensive but also for renoprotective purposes in diabetic and non-diabetic nephropathies.

Progressive renal insufficiency. Office strategies to prevent or slow progression of kidney disease

Prevention of chronic renal failure should be a primary healthcare goal in the new millennium. Better control of blood pressure, blood glucose, and lipid levels shows promise for slowing and perhaps even preventing renal dysfunction. Protein-sparing diets also may prove to be important. While it is not yet known whether combining interventions to treat each of these factors will have additive or synergistic effects, it seems prudent to approach these problems aggressively.

Predictors of the development of hyperkalemia in patients using angiotensin-converting enzyme inhibitors

BACKGROUND/AIMS

Angiotensin-converting enzyme inhibitors (ACEI) are the antihypertensives of choice in patients with chronic renal failure (CRF). ACEI by decreasing the synthesis of aldosterone, the main regulator of serum potassium, predispose to the development of hyperkalemia. Although hyperkalemia with administration of ACEI is uncommon in patients with a normal renal function, a preexisting abnormality in potassium hemostasis, as seen in patients with chronic renal failure, may increase the risk of hyperkalemia.

METHOD

To determine the predictors of development of hyperkalemia (K >5.1 mEq/l) in patients on ACEI, we retrospectively reviewed medical records of 119 patients followed in our renal clinic.

RESULTS

The mean age of the patients was 56 +/- (SD) 13 (range 20-84) years. Sixty-three percent were males, and 37% were females. Sixty-seven percent had a history of diabetes. Eighty five percent of the patients had CRF [creatinine clearance (CrCl) <80 ml/min]. The baseline serum Cr was 2.3 +/- 1.2 (range 0.6-6.9) mg/dl, and the CrCl was 50 +/- 27.5 ml/min. Of the 119 patients 46 (38.6%) developed hyperkalemia (mean K 5.68 +/- 0.3, range 5.2-6.7 mEq/l). Ninety-six percent of the patients who developed hyperkalemia had CRF, and 84% were diabetics. Pearson product-moment correlation revealed a significant positive correlation of hyperkalemia with Cr and a negative correlation of hyperkalemia with CrCl and HCO(3) (Cr: r = 0.42, p < 0.0001; CrCl: r = -0.34, p < 0.0001; HCO(3): r = -0.41, p < 0.0001). Multivariate logistic regression analysis revealed diabetes and serum creatinine to be the main predictors of hyperkalemia. In 31 patients hyperkalemia resolved either with a low-potassium (2 g/day) diet or with diet and a decrease in the dose of ACEI. In 15 patients ACEI had to be discontinued due to persistent hyperkalemia.

CONCLUSIONS

We conclude that hyperkalemia is common in patients with CRF on ACEI. The majority of the patients who develop hyperkalemia on ACEI have CRF and diabetes. A large number of patients with CRF require discontinuation of ACEI due to hyperkalemia and are deprived of their renoprotective effects.

The role of protein traffic in the progression of renal diseases

Progression to irreversible renal parenchymal damage and end-stage renal disease is the final common pathway of chronic proteinuric nephropathies and is relatively independent of the type of initial insult. In animals, a reduction in nephron mass exposes the remaining nephrons to adaptive hemodynamic changes that are intended to sustain renal function but may be detrimental in the long term. High glomerular capillary pressure impairs glomerular permeability to proteins, which are then filtered in excessive quantities and reach the lumen of the proximal tubule. The secondary process of reabsorption of filtered proteins can contribute substantially to renal interstitial injury by activating intracellular events, including upregulation of vasoactive and inflammatory genes. The corresponding molecules formed in excessive amounts by the renal tubules cause an interstitial inflammatory reaction that normally precedes renal scarring and correlates with declining function. In several clinical studies, the increase in urinary protein excretion correlated with the tendency of the renal disease to progress more than it correlated with the underlying renal disease itself. Whenever urinary protein excretion is reduced, the decline in the glomerular filtration rate (GFR) slows or stops. Thus, to the extent that angiotensin-converting enzyme inhibitors lower the rate of urinary protein excretion, they effectively limit the progressive decline in GFR. If treatment is sufficiently prolonged, the GFR decline can be effectively halted or reversed, even in patients with remarkably severe disease, and remission is now achievable in some patients.

The ACE insertion/deletion polymorphism has no influence on progression of renal function loss in autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) shows a variable clinical course that is not fully explained by the genetic heterogeneity of this disease. We looked for a possible genetic modifier, the ACE I/D polymorphism, and its influence on progression towards end-stage renal failure (ESRF).

METHODS

Forty-nine ADPKD patients who reached ESRF <40 years, and 21 PKD1 patients who reached ESRF > 60 years or were not on dialysis at 60 years of age were recruited. Clinical data were provided by questionnaires. Blood was collected for the determination of the ACE insertion/deletion (I/D) polymorphism genotype. The ACE genotype was also determined in a general, control PKD1 group (n=59).

RESULTS

Patients who reached ESRF <40 years had significantly more early onset hypertension than patients reaching ESRF >60 years (80% vs 21%; P<0.001). The ACE genotype distribution showed no differences between the groups of the rapid progressors (DD 20%, ID 56%, II 24%), the slow progressors (DD 29%, ID 52%, II 19%) and the general PKD1 control population (DD 31%, ID 47%, II 22%).

CONCLUSION

There is no relationship between progression towards ESRD and the ACE I/D polymorphism in ADPKD patients.

Chronic proteinuric nephropathies: outcomes and response to treatment in a prospective cohort of 352 patients with different patterns of renal injury

The Ramipril Efficacy in Nephropathy (REIN) study found that angiotensin-converting enzyme (ACE) inhibitors effectively decreased proteinuria, glomerular filtration rate (GFR) decline (DeltaGFR), and incidence of end-stage renal disease (ESRD) in patients with proteinuric chronic nephropathies. In this study, we prospectively investigated the main clinical determinants of progression and response to treatment in the 352 patients enrolled into the REIN study. Mean DeltaGFR (0.56 +/- 0.05 [SEM] versus 0.21 +/- 0.05 mL/min/1.73 m(2)/mo; P = 0.0001) and incidence of ESRD (30% and 10%; P = 0.0001) were more than twice that in patients with proteinuria of 2 g/24 h or greater of protein compared with those with protein less than 2 g/24 h (relative risk [RR], 4.07; 95% confidence interval [CI], 2.20 to 7.52), as well as in patients with hypertension compared with normotension (mean DeltaGFR, 0.48 +/- 0. 05 versus 0.22 +/- 0.05 mL/min/1.73 m(2)/mon; P = 0.0006; ESRD, 25% versus 10%; P = 0.004; RR, 3.18; 95% CI, 1.38 to 7.32). Hypertension at study entry (P = 0.038), greater mean blood pressure on follow-up (P = 0.002), and urinary protein excretion rate (P = 0.0001) were independent predictors of faster DeltaGFR. DeltaGFR was approximately twofold faster in patients with type 2 diabetes than in those with primary glomerular disease (P = 0.002; including immunoglobulin A [IgA] nephropathy, P = 0.009); nephrosclerosis (P = 0.03), adult polycystic kidney disease (APKD), or chronic interstitial nephritis (P = 0.006). Diabetes at study entry (P = 0. 02) and greater mean blood pressure (P = 0.0001) and urinary protein excretion rate (P = 0.0001) on follow-up were independent predictors of faster DeltaGFR. After correction for baseline covariates, diabetes was also associated with an increased risk for progression to ESRD (RR, 2.39; 95% CI, 1.01 to 5.68; P < 0.05). At multivariate analyses, ramipril significantly decreased DeltaGFR (regression coefficient,-0.23 +/- 0.11 [SEM]; P = 0.036) and ESRD (RR, 2.08; 95% CI, 1.21 to 3.57; P = 0.008) in patients with baseline proteinuria of 2 g/24 h or greater of protein, and the renoprotective effect increased for increasing levels of proteinuria. Ramipril decreased DeltaGFR to a similar extent in normotensive and hypertensive patients (-0.14 +/- 0.11 versus -0.14 +/- 0.09) and significantly limited ESRD in hypertensive patients (RR, 2.03; 95% CI, 1.26 to 3. 26; P = 0.004). DeltaGFR was decreased by 42% in primary glomerular disease (P = 0.017), by 35% in IgA nephropathy, and by 37% in nephrosclerosis, but was not improved in type 2 diabetes, APKD, or interstitial nephritis. At multivariate analyses, ramipril significantly slowed DeltaGFR (-0.24 +/-0.08; P = 0.004) and progression to ESRD (RR, 2.32; 95% CI, 1.36 to 3.96; P = 0.002) in patients without diabetes, but not in patients with diabetes, who tended to have a faster DeltaGFR (+0.62 +/- 0.44) on ramipril therapy. In summary, patients with proteinuria of 2 g/24 h or greater of protein, preexisting hypertension, or type 2 diabetes were faster progressors. Greater blood pressure and degree of proteinuria were the strongest determinants of faster GFR decline. The renoprotective effect of ramipril was similar in patients with normotension and hypertension. Hypertensive patients and those with proteinuria of 2 g/24 h or greater of protein, primary glomerular disease, or nephrosclerosis gained the most from ACE inhibitor treatment. During the study period, those with proteinuria less than 2 g/24 h of protein, type 2 diabetes, or polycystic kidney disease did not benefit by treatment to an appreciable extent.

[Factors associated with changes in microalbuminuria during antihypertensive treatment]

BACKGROUND

The objective of the present study was to analyze the factors related with changes of microalbuminuria during antihypertensive treatment in patients with essential hypertension.

METHODS

One hundred and six patients (57 men, mean age 40.8 [SD 6.6] years) never treated with antihypertensive treatment were included. At the beginning and after one year, blood pressure biochemical profile and urinary albumin excretion (UAE) were measured. After the initial evaluation, 53 patients received angiotensin converting enzyme inhibitors (ACEi) and 53 beta-blockers (BB). Hydrochlorothiazide was added to achieve the blood pressure target < 140/90 mmHg.

RESULTS

The average of UAE was 32.1 (43.1) mg/24 h, and 41 (39%) patients had microalbuminuretics. After 12 months of treatment, a significative fall of systolic BP (-20.6 [8.03] mmHg, p < 0.001), and diastolic BP (-14.18 [10.34] mmHg, p < 0.001) were observed, whereas baseline glucose increases (3.08 [11.07] mg/dl, p = 0.006). The changes of UAE were only related with the baseline UAE values. Neither, age, sex, baseline diastolic BP and changes in diastolic BP were significantly related with the changes in UAE. In spite of similar mean BP reduction (medial BP 17.4 [10.9] vs 14.8 [10.4] mmHg), UAE only was reduced in patients treated with ACEi (LogUAE: 0.203 [0.872] mg/24 h; p < 0.04). In addition, in patients treated with BB a significative increase in baseline glucose (4.4 [12.3] mg/dl; p = 0.013) and uric acid (1.18 [4.18]; p = 0.031) were observed.

CONCLUSIONS

In patients with essential hypertension, changes in microalbuminuria depends of the initial UAE values and the kind of antihypertensive treatment. ACEi produced higher UAE reduction and lower derangement of the glucose metabolism than BB.

Focal segmental glomerulosclerosis in African Americans: effects of steroids and angiotensin converting enzyme inhibitors

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is a common primary glomerulopathy in African Americans. In this report, we present data on 40 African American patients with FSGS from our medical center.

METHODS

Patients were identified from a review of all charts seen in our conservative management renal clinic in 1996, a review of renal biopsy rolls (1994-1998), and a review of patients entering the end-stage renal disease (ESRD) program with a primary diagnosis of FSGS (1993- 1997). Charts were reviewed for demographic, biopsy, and treatment data. Patients who were observed for at least 4 months (range, 4-125 months) were included. ESRD was used as the primary endpoint (n = 12). Data were analyzed using univariate and multivariate Cox hazards and Kaplan-Meier survival analysis. Twenty-four patients were treated with angiotensin-converting enzyme (ACE) inhibitors. Similarly, 24 patients were treated with corticosteroids for a mean of 8.75 +/- 2.6 months and a total dose of 9.3 +/- 2.2 g.

RESULTS

On univariate analysis, factors found to be significant determinants for reaching ESRD were the initial creatinine (P = 0.0001), interstitial fibrosis (P = 0.032), the percentage of globally sclerosed glomeruli (P = 0.0018), and the mean arterial blood pressure over the course of follow-up (P = 0.05). Neither the ACE inhibitors nor the corticosteroids had a significant impact on reaching ESRD. The patients reaching ESRD (n = 12) were analyzed separately. The mean time from biopsy to ESRD was 24.7 +/- 9.8 months. ACE inhibitors prolonged renal survival (P = 0.023), but steroids did not. Initial creatinine was the only factor found to be a significant determinant for ESRD.

CONCLUSIONS

We conclude that FSGS is common in African Americans. Early diagnosis and blood pressure control are important, but the beneficial effects of steroids and ACE inhibitors in this population are still unclear.

A clinicopathological study of IgA nephropathy in renal transplant recipients: beneficial effect of angiotensin-converting enzyme inhibitor

BACKGROUND

Prolonging the survival of transplant kidneys is a major task of modern nephrology. It has recently been shown that deteriorating renal function and substantial graft loss were observed in 55% of renal allograft recipients with recurrent IgA nephropathy (IgAN) at long-term follow-up. To gain a useful insight into the therapeutic approach towards protecting allograft kidneys from deteriorating graft function, we compared the histological characteristics of post-transplant IgAN to primary IgAN and investigated the effects of an ACE inhibitor.

METHODS

Twenty-one patients with post-transplant IgAN and 63 patients with primary IgAN were included in the histopathological study. The effectiveness of angiotensin-converting enzyme (ACE) inhibitor treatment in post-transplant IgAN was also studied in 10 patients.

RESULTS

The prevalence of glomeruli with adhesions and/or cellular crescents in primary IgAN was significantly greater than in post-transplant IgAN (P<0.05), but the proportion of glomeruli with segmental sclerosis was similar in both groups. The rate of global obsolescence, and the degree of interstitial fibrosis in post-transplant IgAN were significantly greater than in primary IgAN (P<0.05). The degree of glomerular obsolescence and the severity of interstitial fibrosis correlated with the severity of glomerular lesion in primary IgAN, but not in post-transplant IgAN. In primary IgAN, glomerular diameter significantly correlated with the proportions of glomerular obsolescence, but not in post-transplant IgAN, suggesting that allograft kidneys may be in a hyperfiltration state. Both the blood pressure and the urinary protein excretion significantly improved after ACE-inhibitor treatment (P<0.001).

CONCLUSION

In post-transplant IgAN, histopathological lesions indicative of acute inflammatory insults were suppressed, and glomerular hypertrophy, which may relate to haemodynamic burden such as hyperfiltration, was prominent. Preliminary study of ACE-inhibitor treatment in 10 patients showed favourable effects. A future long-term follow-up study is required to establish the effectiveness of ACE inhibitors in treatment of post-transplant IgAN.

Insertion/deletion polymorphism in ACE gene is not associated with renal progression in Japanese patients with IgA nephropathy

We determined the relationship between the gene polymorphism of angiotensin I-converting enzyme (ACE) and the progression of immunoglobulin A (IgA) nephropathy in a large cohort in a multicenter trial of ethnically homogeneous Japanese patients (n = 527). Patients with biopsy-proven IgA nephropathy were recruited from several clinics in Japan. The mean observation period was 8.4 +/- 4.7 years. ACE insertion/deletion (I/D) genotype was determined by polymerase chain reaction amplification using allele-specific primers. Clinical factors investigated in all patients were date of birth, sex, levels of urinary protein excretion, duration of observation, serum creatinine (sCr) level, and creatinine clearance (CCr). ACE genotype distribution did not differ between patients who maintained normal renal function (II, 41%; ID, 44.7%; DD, 14.3%) and those who progressed to renal impairment (II, 41.7%; ID, 40.4%; DD, 17.9%). Kaplan-Meier analysis did not show a significant difference in renal survival rate among the three groups of each genotype. In multivariate analysis, only two variables, proteinuria greater than 1.0 g/d of protein and impaired renal function (sCr >1.2 mg/dL or CCr <70 mL/min) at the time of renal biopsy, were found to be risk factors for disease progression leading to a poor outcome. No association was observed between these variables and ACE genotype. It appears that ACE I/D polymorphism may not affect the progressive deterioration of renal function in patients with IgA nephropathy from our multicenter trial.

Renal and systemic effects of continued treatment with renin inhibitor remikiren in hypertensive patients with normal and impaired renal function

BACKGROUND

Remikiren is an orally active renin inhibitor with established antihypertensive efficacy. As a single dose it induces renal vasodilatation, suggesting specific renal actions. Data on the renal effects of continued treatment by renin inhibition are not available, either in subjects with normal, or in subjects with impaired renal function.

METHODS

The effect of 8 days of treatment with remikiren 600 mg o.i.d. on blood pressure, renal haemodynamics, and proteinuria was studied in 14 hypertensive patients with normal or impaired renal function.The study was conducted on an ambulatory in-hospital basis and was designed in a single-blind, longitudinal order.

RESULTS

Remikiren induced a significant peak fall in mean arterial pressure of 11.2+/-0.8%, with corresponding trough values of -6+/-0.8%. This fall was somewhat more pronounced in the patients with renal function impairment (-13.3 vs -9.6%; P<0.01). Glomerular filtration rate remained stable, whereas effective renal plasma flow increased from 301+/-35 to 330+/-36 ml/min/1.73 m(2) (P<0.05). Filtration fraction and renal vascular resistance fell by 10+/-2% and 15+/-2% respectively (both P<0.01). Remikiren induced a cumulated sodium loss of -82+/-22 mmol and a positive potassium balance of 49+/-9 mmol (both P<0.01). During remikiren, proteinuria fell by 27% (range -18 to -38%; P<0.01) in the patients with overt proteinuria at onset (n=6). In the remainder of the patients albuminuria fell by 20% (range -1 to -61%, P<0.05). No side-effects were observed.

CONCLUSIONS

Continued treatment with remikiren induced a sustained fall in blood pressure, renal vasodilatation, negative sodium balance, and a reduction in glomerular protein leakage. These data are consistent with a renoprotective potential of renin inhibition.

Renoprotective benefits of RAS inhibition: from ACEI to angiotensin II antagonists

In landmark clinical trials, pharmacological inhibition of the renin-angiotensin system (RAS) with angiotensin-converting enzyme inhibitors (ACEIs) attenuated the decline in renal function associated with chronic renal disease (CRD). Hemodynamic and nonhemodynamic effects of angiotensin II (Ang II) attest to its central role in the pathogenesis of CRD. Angiotensin II subtype 1 receptor antagonists (AT1RA) differ from ACEI in their effects on the RAS and on bradykinin metabolism. Elevations in bradykinin levels associated with ACEI and stimulation of angiotensin subtype 2 receptors resulting from AT1RA may produce therapeutic effects unique to each class of drug. Nevertheless, in animal models of CRD, ACEI and AT1RA exert equivalent renoprotection, implying that their renoprotective effects result primarily from inhibition of Ang II-mediated stimulation of angiotensin subtype 1 receptors. Clinical data comparing ACEI and AT1RA therapy in renal disease are limited to short-term studies, which indicate that AT1RAs have equivalent effects to ACEI on the major determinants of CRD progression, namely blood pressure and proteinuria. AT1RAs were well tolerated, with side-effect profiles similar to placebo. Taken together, available evidence suggests that AT1RAs will share the renoprotective properties of ACEI in human CRD. Nevertheless, the results of long-term clinical trials are required before AT1RA can be recommended as an alternative to ACEI in renoprotective therapy.