Effects of ACE inhibition in normotensive patients with chronic glomerular disease and normal renal function

A data-driven approach to identify risk profiles and protective drugs in COVID-19

As the COVID-19 pandemic is spreading around the world, increasing evidence highlights the role of cardiometabolic risk factors in determining the susceptibility to the disease. The fragmented data collected during the initial emergency limited the possibility of investigating the effect of highly correlated covariates and of modeling the interplay between risk factors and medication. The present study is based on comprehensive monitoring of 576 COVID-19 patients. Different statistical approaches were applied to gain a comprehensive insight in terms of both the identification of risk factors and the analysis of dependency structure among clinical and demographic characteristics. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus enters host cells by binding to the angiotensin-converting enzyme 2 (ACE2), but whether or not renin-angiotensin-aldosterone system inhibitors (RAASi) would be beneficial to COVID-19 cases remains controversial. The survival tree approach was applied to define a multilayer risk stratification and better profile patient survival with respect to drug regimens, showing a significant protective effect of RAASi with a reduced risk of in-hospital death. Bayesian networks were estimated, to uncover complex interrelationships and confounding effects. The results confirmed the role of RAASi in reducing the risk of death in COVID-19 patients. De novo treatment with RAASi in patients hospitalized with COVID-19 should be prospectively investigated in a randomized controlled trial to ascertain the extent of risk reduction for in-hospital death in COVID-19.

Correlation between dipstick urinalysis and urine sediment microscopy in detecting haematuria among children with sickle cell anaemia in steady state in Ilorin, Nigeria

Introduction

Haematuria is one of the clinical manifestations of sickle cell nephropathy. Although dipstick urinalysis detects haemoglobin and by extension haematuria; it does not confirm haematuria. Urine sediment microscopy confirms haematuria and constitutes a non-invasive “renal biopsy”. The need to correlate dipstick urinalysis and urine sediment microscopy findings becomes important because of the cheapness, quickness and simplicity of the former procedure.

Methods

Dipstick urinalysis and urine sediment microscopy were carried (both on first contact and a month after) among consecutive steady state sickle cell anaemia children attending sickle cell clinic at the University of Ilorin Teaching Hospital between October 2004 and July 2005.

Results

A total of 75 sickle cell anemia children aged between 1-17 years met the inclusion criteria. Haematuria was found in 12 children (16.0%) and persistent haematuria in 10 children 13.3%. Age and gender did not have significant relationship with haematuria both at first contact (p values 0.087 and 0.654 respectively) and at follow-up (p values 0.075 and 0.630 respectively). Eumorphic haematuria was confirmed in all the children with persistent haematuria with Pearson correlation +0.623 and significant p value of 0.000.

Conclusion

The study has revealed a direct significant correlation for haematuria detected on dipstick urinalysis and at urine sediment microscopy. It may therefore be inferred that dipstick urinalysis is an easy and readily available tool for the screening of haematuria among children with sickle cell anaemia and should therefore be done routinely at the sickle cell clinics.

Effect of captopril treatment on recuperation from ischemia/reperfusion-induced acute renal injury

BACKGROUND

Ischemia/reperfusion triggers acute kidney injury (AKI), mainly via aggravating hypoxia, oxidative stress, inflammation and renin-angiotensin system (RAS) activation. We investigated the role of angiotensin-converting enzyme (ACE) inhibition on the progression of AKI in a rat model of ischemia/reperfusion.

METHODS

Ninety-nine Sprague-Dawley rats were subjected to 1 h ischemia/reperfusion and/or left unilateral nephrectomy, with concurrent intraperitoneal implantation of Alzet pump. Via this pump, they were continuously infused with captopril 0.5 mg/kg/day, captopril 2 mg/kg/day or saline. The rats were sacrificed following 24, 48 or 168 h. Blood samples, 24-h urine collections and kidneys were allocated, to evaluate renal function, angiotensin-II, nitric oxide (NO), apoptosis, hypoxia, oxidative stress and inflammation.

RESULTS

Serum creatinine and cystatin-C significantly increased in ischemic rats, coinciding with histopathologic intrarenal damage, decreased NO, augmented angiotensin-II, interleukin (IL)-6, IL-10, transforming growth factor-beta. At the acute reperfusion stage, captopril prevented excessive angiotensin-II synthesis, ameliorated renal dysfunction, inhibited intrarenal inflammation and improved histopathologic findings. Most of the renoprotective effects of captopril were limited predominantly to acute reperfusion stage. Concurrently, captopril significantly decreased NO availability, exacerbated intrarenal hypoxia and augmented oxidative stress.

CONCLUSIONS

At the acute stage of renal ischemia/reperfusion-induced AKI, ACE inhibition substantially contributed to the amelioration of acute injury by improving renal function, inhibiting systemic and intrarenal angiotensin-II, attenuating intrarenal inflammation and preserving renal tissue structure. Later on, at the post-reperfusion stage, most of the beneficial effects of captopril administration on the recuperating post-ischemic kidney were no longer evident. Concurrently, ACE inhibition exacerbated intrarenal hypoxia and accelerated oxidative stress, indicating that renal adaptation to some consequences of ischemia does require bioavailability of RAS components.

Antihypertensive and organ-protective effects of benazepril

Benazepril is a nonsulfhydryl ACE inhibitor with favorable pharmacodynamic and pharmacokinetic properties, well-established antihypertensive effects and a good tolerability profile. Recent clinical studies have demonstrated that patients treated with benazepril alone or in combination with hydrochlorothiazide or amlodipine may achieve beneficial renal outcomes that extend beyond blood pressure control. Furthermore, the recent Avoiding Cardiovascular Events Through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH) trial showed decreased cardiovascular morbidity and mortality with benazepril when administered as a cotreatment. An additional novel therapeutic area for benazepril is atrial fibrillation. Differences between combination therapies have implications for which patients may be best suited to particular interventions, and further studies are required to fully ascertain this potential.

Enalapril dosage in steroid-resistant nephrotic syndrome

We have examined, in a randomized crossover trial, the antiproteinuric effect of treatment with low- (0.2 mg/kg daily) and high-dose (0.6 mg/kg daily) enalapril in 25 consecutive patients with steroid-resistant nephrotic syndrome (SRNS). Patients in group A ( n=11) received enalapril at low doses for 8 weeks, followed by 2 weeks of washout and then at high doses for 8 weeks. Those in group B ( n=14) initially received enalapril at high and then low doses. Patients continued to receive treatment with tapering doses of prednisolone; none received concomitant therapy with daily oral or intravenous steroids, alkylating agents, cyclosporine, non-steroidal anti-inflammatory drugs, and other antihypertensive medications. The urine albumin-to-creatinine (Ua/Uc) ratio and the percentage reduction were determined for each phase of therapy. Baseline clinical, biochemical, and histological features were comparable in the two groups. In the first phase, treatment with low-dose enalapril (group A) resulted in median 34.8% Ua/Uc reduction compared with 62.9% with high doses (group B) ( P<0.01). High-dose enalapril was associated with a significant reduction in Ua/Uc ratio in both groups. The combined median Ua/Uc (95% confidence interval) reduction in the low-dose phase was 33% (-10.3% to 72.4%) and in the high-dose 52% (15.4%-70.4%) ( P<0.05). The median Ua/Uc ratio at the end of 20 weeks was 1.1 and 1.8 in groups A and B, respectively ( P>0.05). Systolic and diastolic blood pressure reductions were similar in both groups. No period or carry-over effect was found. Prolonged treatment with enalapril thus resulted in a dose-related reduction in nephrotic-range proteinuria. Titration of the dose of enalapril may be a useful strategy for achieving substantial reduction of proteinuria in children with SRNS.

Nitrendipine and amlodipine mimic the acute effects of enalapril on renal haemodynamics and reduce glomerular hyperfiltration in patients with chronic kidney disease

Antihypertensive drugs may have an important effect on glomerular haemodynamics. In chronic nephropathy patients, we compared the effect on glomerular haemodynamics of two second-generation dihydropyridinic agents, nitrendipine and amlodipine, with a first generation dihydropyridinic agent and an ACE-inhibitor, enalapril. In all, 32 patients (pts), divided into four groups, received the different drugs: ENA (enalapril, eight pts), NIF (nifedipine, eight pts), NIT (nitrendipine, eight pts) AML (amlodipine, eight pts). The study assessed the effect on glomerular haemodynamics of a single administration of the test drug in baseline conditions and in glomerular hyperfiltration experimentally induced by amino-acid infusion. The glomerular filtration rate (GFR, measured by inulin clearance), effective renal plasma flow (ERPF, measured by p-aminohippurate clearance), renal vascular resistances (RVR) and filtration fraction (FF) were assessed. Administration of AML and NIT test dose reduced FF, as did ENA, but not NIF, in both baseline (AML: P=0.005; NIT: P=0.02; ENA: P=0.007) and glomerular hyperfiltration conditions (AML: P=0.0003; NIT: P=0.03; ENA: P=0.00006). In baseline conditions, only ENA resulted in a significant drop in the GFR (P=0.008), while NIF, NIT and AML induced a significant increase (P=0.003, 0.03, 0.0001, respectively). However, in hyperfiltration conditions, NIT (0.08) and AML (0.00003) caused a decrease in the GFR, as did ENA (0.0003) but not NIF. In all the experimental conditions, a RVR reduction and an ERPF increase were observed. Single dose of NIT and AML were effective in attenuating the effect of amino-acid infusion on glomerular filtration, similar to ENA; this effect of NIT and AML on the glomerular filtration rate is not observed under basal conditions.

ACEI/ATRA therapy decreases proteinuria by improving glomerular permselectivity in IgA nephritis

BACKGROUND

It has been postulated that angiotensin-converting enzyme inhibitor/angiotensin receptor antagonist (ACEI/ATRA) may decrease proteinuria in patients with glomerulonephritis by its action on the glomerular basement membrane. We therefore studied the relationship between the response of patients with IgA nephritis (IgAN) to ACEI/ATRA therapy by decreasing proteinuria and its effect on the selectivity index (SI) in these patients.

METHODS

Forty-one patients with biopsy-proven IgAN entered a control trial, with 21 in the treatment group and 20 in the control group. The entry criteria included proteinuria of 1 g or more and/or renal impairment. Patients in the treatment group received ACEI/ATRA or both with three monthly increases in dosage. In the control group, hypertension was treated with atenolol, hydrallazine, or methyldopa. The following tests were performed at three monthly intervals: serum creatinine, total urinary protein, SI, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and low molecular weight (LMW) proteinuria.

RESULTS

After a mean duration of therapy of 13 +/- 5 months, in the treatment group, there was no significant change in serum creatinine, proteinuria, or SI, but in the control group, serum creatinine deteriorated from 1.8 +/- 0.8 to 2.3 +/- 1.1 mg/dL (P < 0.05). Among the 21 patients in the treatment group, 10 responded to ACEI/ATRA therapy determined as a decrease in proteinuria by 30% (responders), and the other 11 did not respond (nonresponders). Among the responders, SI improved from a mean of 0.26 +/- 0.07 to 0.18 +/- 0. 07 (P < 0.001), indicating a tendency toward selective proteinuria. This was associated with an improvement in serum creatinine from mean 1.7 +/- 0.6 to 1.5 +/- 0.6 mg/dL (P < 0.02) and a decrease in proteinuria from a mean of 2.3 +/- 1.1 to 0.7 +/- 0.5 g/day (P < 0. 001). After treatment, proteinuria in the treatment group (1.8 +/- 1. 6 g/day) was significantly less than in the control group (2.9 +/- 1. 8 g/day, P < 0.05). The post-treatment SI in the responder group (0. 18 +/- 0.07) was better than that of the nonresponder group (0.33 +/- 0.11, P < 0.002). Eight out of 21 patients in the treatment group who had documented renal impairment had improved renal function compared with two in the control group (chi2 = 4.4, P < 0. 05). Of the eight patients in the treatment group who improved their renal function, three normalized their renal function compared with one from the control group.

CONCLUSION

Our data suggest that ACEI/ATRA therapy may be beneficial in patients with IgAN with renal impairment and nonselective proteinuria, as such patients may respond to therapy with improvement in protein selectivity, decrease in proteinuria, and improvement in renal function. ACEI/ATRA therapy probably modifies pore size distribution by reducing the radius of large unselective pores, causing the shunt pathway to become less pronounced, resulting in less leakage of protein into the urine.

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.

A DNA element in the alpha1 type III collagen promoter mediates a stimulatory response by angiotensin II

BACKGROUND

Angiotensin II (Ang II) plays an important role in extracellular matrix deposition and tissue scarring in the kidney and the heart. The mechanism for extracellular matrix stimulation by Ang II is currently hypothetical, with one possibility pointing to a direct effect on cell synthesis of specific collagens.

METHODS

We studied the molecular mechanism for activation of type III collagen synthesis by Ang II in an in vitro cell model of myofibroblasts by evaluating (1) alpha1(III) collagen mRNA expression; (2) alpha1(III) collagen promoter activity; (3) DNA/protein binding with characterization of binding sites; (4) expression of transcription factors; and (5) the role of a short DNA segment as Ang II responsive element.

RESULTS

We found a specific dose-dependent stimulation of alpha1(III) collagen mRNA expression and a parallel effect on alpha1(III) collagen promoter activity. Transfection of constructs containing alpha1(III) collagen promoter fragments of different lengths localized the site of activation within the shortest 178 bp construct. By gel-retardation experiments, we observed the formation of a DNA-protein complex with crude extracts from Ang II-stimulated cells and an oligonucleotide spanning the 3 to 20 sequence. This complex was due to a sequence-specific interaction and was abolished by a 3 bp substitution mutation. The introduction of this mutation into the 178 bp construct abolished the stimulatory effect of Ang II.

CONCLUSIONS

These results demonstrate that Ang II stimulates the expression of alpha1(III) collagen mRNA in myofibroblasts in vitro by activating the alpha1(III) collagen promoter at the level of a factor recognition site localized immediately downstream of the transcription start site. This mechanism could be involved in Ang II-induced renal and heart fibrosis.

Microalbuminuria in essential hypertension: significance, pathophysiology, and therapeutic implications

Some patients with essential hypertension manifest greater than normal urinary albumin excretion (UAE). The significance of this association, which is the object of this review, is not well established. Hypertensive patients with microalbuminuria manifest greater levels of blood pressure, particularly at night, and higher serum levels of cholesterol, triglycerides, and uric acid than patients with normal UAE. Levels of high-density lipoprotein cholesterol, on the other hand, were lower in patients with microalbuminuria than in those with normal UAE. Patients with microalbuminuria manifested greater incidence of insulin resistance and thicker carotid arteries than patients with normal UAE. After a follow-up of 7 years, we observed that 12 cardiovascular events occurred among 54 (21.3%) patients with microalbuminuria and only two such events among 87 patients with normal UAE (P < 0.0002). Stepwise logistic regression analysis showed that UAE, cholesterol level, and diastolic blood pressure were independent predictors of the cardiovascular outcome. Rate of creatinine clearance from patients with microalbuminuria decreased more than that from those with normal UAE. In conclusion, these studies suggest that hypertensive individuals with microalbuminuria manifest a variety of biochemical and hormonal derangements with pathogenic potential, which results in hypertensive patients having a greater incidence of cardiovascular events and a greater decline in renal function than patients with normal UAE.

A new dimension to the Barker hypothesis: low birthweight and susceptibility to renal disease

BACKGROUND

There is an epidemic of renal failure among Aborigines in the Australia's Northern Territory. The incidence is more than 1000 per million, and is doubling every three to four years. We evaluated the relationship of birthweight to renal disease in adults in one high-risk community.

METHODS

We screened more than 80% of people in the community for renal disease, using the urine albumin/creatinine ratio (ACR, g/mol) as the marker, and reviewed records for birthweights.

RESULTS

Birthweights were available with increasing frequency for people born after 1956. In 317 adults aged 20 to 38 years at screening, the mean birthweight (SD) was 2.712+/-0.4 kg, and 35% had been low birthweight (LBW, less than 2.5 kg). Birthweight was positively correlated with body mass index (BMI), blood pressure, and diabetes rates, but was inversely correlated with ACR. The odds ratio for overt albuminuria in LBW persons compared with those of higher birthweights was 2.82 (CI, 1.26 to 6.31) after adjusting for other factors, and LBW contributed to an estimated 27% (CI, 3 to 45%) of the population-based prevalence of overt albuminuria. Multivariate models suggest that increasing BMI and blood pressure and decreasing birthweight act in concert to amplify the increases in ACR that accompany increasing age.

CONCLUSIONS

LBW contributes to renal disease in this high-risk population. The association might be mediated through impaired nephrogenesis caused by intrauterine malnutrition. The renal disease epidemic in Aborigines may partly be the legacy of greatly improved survival of LBW babies over the last four decades. Disease rates should eventually plateau as birthweights continue to improve, if postnatal risk factors can also be contained.

Angiotensin converting enzyme inhibitors in nondiabetic renal disease

The class of antihypertensive agents that act by blocking angiotensin II has been shown in several experimental models to have the interesting ability to protect the kidney. In patients with nondiabetic renal disease, a number of controlled clinical trials have shown angiotensin converting enzyme inhibitors to achieve a better control of blood pressure and significantly reduce the rate of progression of renal failure in comparison with conventional agents. In addition, treatment with angiotensin converting enzyme inhibitors has helped to achieve new information on the optimal blood pressure target to be reached in order to protect the residual renal function maximally.

Urinary findings and renal function in adult Navajo Indians and associations with type 2 diabetes

We screened a sample of adult Navajo Indians for signs of renal disease that might underlie their increasing rates of renal failure. Nondiabetics had modest rates of hypertension, which was more common in males and increased with age. Microscopic hematuria was very common, and only a fraction was associated with progressive nephropathy. Microalbuminuria, mostly undetected by routine dipstick, was present in 14.6% of subjects; overt albuminuria was present in 2%. Increasing albuminuria was related to renal insufficiency, which was more common in males. Hypertension was associated with greater then threefold increases in both albuminuria and renal insufficiency. Cardiovascular disease was uncommon and had no discernible relationship to albuminuria. Most diabetic patients (58.4%) had hypertension, with equal rates for males and females. Fully half of all diabetic patients had unsatisfactory blood pressure levels at screening. Rates and patterns of hematuria were like those of nondiabetics. Microalbuminuria was present in 36.1% and overt albuminuria in 17.9%, four and eight times the rates in matched nondiabetics, respectively; these differences persisted after controlling for blood pressure. Renal insufficiency was associated with progressive albuminuria and was present in 10.6%, with equal rates in males and females. Hypertension, albuminuria, and renal insufficiency, but not hematuria, increased with increasing diabetes duration. Hypertension was associated with a twofold increase in albuminuria, a threefold increase in overt albuminuria, and an eightfold increase in renal insufficiency. Cardiovascular disease had no detectable association with microalbuminuria, but had a strong relationship to overt albuminuria. The high rates of hematuria are not well explained. It probably has nonrenal as well as renal origins, the latter including mesangial proliferative glomerulonephritis. The impressive rates of albuminuria among diabetic patients mark a large reservoir of renal disease and fore-shadow even larger burdens of end-stage renal disease and cardiovascular disease in the near future. Improved detection and treatment of hypertension is needed to slow the progression of renal disease in nondiabetics and diabetics, together with screening and treatment protocols for albuminuric diabetic patients. Prevention of albuminuria probably involves population-based modification of blood pressure and metabolic profiles.

Markers for cardiovascular and renal morbidity: expectations for an intervention programme in an Australian aboriginal community

1. Australian Aborigines have high rates of both cardiovascular mortality and renal failure and the usual male dominance in these conditions is respectively reduced and effaced. 2. In one Aboriginal community, we have demonstrated a strong association between albuminuria and cardiovascular risk factors and a relationship of both with insulin resistance, which is more pronounced in females than males. 3. We propose that albuminuria is a component of Syndrome X and that reduction in levels of albuminuria should prove to be a useful marker of effectiveness in treatment programmes targeting cardiovascular risk as well as renal disease.

Longitudinal evaluation of renal function in non-insulin-dependent diabetic patients with early nephropathy: effects of angiotensin-converting enzyme inhibition

A prospective self-controlled evaluation of renal function in non-insulin-dependent diabetic patients with early nephropathy, mild to moderate hypertension, and retinopathy was undertaken over a 1-year period. Thereafter, the effects of treatment with captopril on blood pressure, albumin excretion, and renal function were assessed. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and systolic and diastolic blood pressures remained stable during the pretreatment period; 24-h urinary protein excretion increased progressively from 0.79 +/- 0.13 to 1.23 +/- 0.18 g/24 h (p < 0.05) (mean +/- standard error). Captopril (25 mg b.i.d.) for 3 months reduced systolic and diastolic blood pressures significantly (p < 0.01). Simultaneously, 24-h urinary protein excretion declined by 41 +/- 2.4%, to 0.70 +/- 0.12 g/24 h (p < 0.05) while GFR, ERPF, and fractional filtration demonstrated small but insignificant changes. Subsequently, increase in captopril to 50 mg b.i.d. for the remaining 6 months did not produce further significant changes in renal hemodynamics, blood pressure, or urinary protein excretion (0.48 +/- 0.10 g/24 h at the termination of the study). Non-insulin-dependent diabetic patients with early nephropathy and mild to moderate hypertension demonstrate a progressive increase in urinary protein excretion. Administration of captopril resulted in prompt control of hypertension and reversal of the increase in urinary protein excretion.

Blood pressure reduction initiates the antiproteinuric effect of ACE inhibition

Several observations question the role of blood pressure and renal hemodynamic changes in the long-term antiproteinuric effect of ACE inhibition. To differentiate blood pressure and renal effects in the initial antiproteinuric response, the placebo-controlled acute effects of the ACE inhibitor enalaprilat (10 mg i.v.) on blood pressure, renal hemodynamics, and proteinuria were compared with those of nitroprusside in nine patient with non-diabetic proteinuria. In addition, we studied whether an exogenous angiotensin II infusion reverse the initial enalaprilat-induced antiproteinuric response. Enalaprilat and nitroprusside reduced MAP by -11.3 +/- 2.4% and -14.1 +/- 2.3%, respectively, whereas only enalaprilat showed renal hemodynamic effects, reflected by an increase in ERPF of 18.4 +/- 5.4% and a decrease in FF of -17.1 +/- 2.6%. Despite the contrasting renal hemodynamic profiles, enalaprilat (-10.6 +/- 4.8%) and nitroprusside (-12.8 +/- 5.1% equally decreased proteinuria. Exogenous infusion of angiotensin II completely reversed the blood pressure reduction and renal efferent vasodilatation induced by enalaprilat. proteinuria also increased by 13.1 +/- 7.8% to placebo level, albeit statistically non-significant. We conclude that the initial antiproteinuric effect of ACE inhibition appears to be mediated by blood pressure reduction and does not require its specific renal hemodynamic effect. Further studies should clarify whether the renal efferent vasodilatation during ACE inhibition is required to gradually induce renal structural changes that prevent the abundant passage of proteins.

Effects of fosinopril on exercise tolerance and clinical deterioration in patients with chronic congestive heart failure not taking digitalis. Fosinopril Heart Failure Study Group

A total of 241 men and women with mild to moderately severe chronic heart failure (New York Heart Association functional class II [90%] or III) and a mean (+/- SD) left ventricular ejection fraction of 25 +/- 7%, entered a 24-week, prospective, double-blind, placebo-controlled trial of 10 or 20 mg/day of fosinopril, a phosphinic acid angiotensin-converting enzyme inhibitor. Patients received concomitant diuretic therapy but not digitalis. Primary end points were mean change in maximal treadmill exercise time and occurrence of prospectively defined clinical events indicative of worsening heart failure (most to least severe): death, withdrawal for worsening heart failure, hospitalization for worsening heart failure, need for supplemental diuretic or emergency room visit for worsening heart failure, and no event. At study end point, treadmill exercise time had improved in the fosinopril versus the placebo group (+28.4 vs -13.5 seconds, p = 0.047). New York Heart Association functional class had improved at end point more frequently (24% vs 13%) and deteriorated less frequently (18% vs 32%) in the fosinopril group (p = 0.003). More patients treated with fosinopril (66% vs 50%) remained free of clinical events indicative of worsening heart failure, and fosinopril-treated patients had less severe clinical events (p = 0.004). Dyspnea, fatigue, and paroxysmal nocturnal dyspnea improved more often and worsened less often in this group (p < or = 0.002), and edema showed a trend toward improvement (p = 0.088). These clinical benefits did not require concomitant digitalis therapy. Fosinopril was associated with an acceptable safety profile.

Selected aspects of ACE inhibitor therapy for patients with renal disease: impact on proteinuria, lipids and potassium

Overt proteinuria is often accompanied by hypercholesterolemia and is associated with increased lipoprotein(a) levels. These lipid abnormalities are probably involved in the high incidence of macrovascular complications associated with diabetic nephropathy and possibly other kinds of non-diabetic proteinuric renal disease. Over the last decade many studies have shown that ACE inhibitors can reduce urinary protein excretion but little attention was paid to the impact of this form of therapeutic intervention on the lipid profile. In this article we review our recent data showing that fosinopril administration was associated with significant decreases in both urinary protein excretion, serum total cholesterol levels, and plasma lp(a) levels. The use of ACE inhibitors in patients with renal impairment can result in the development of hyperkalemia as a result of suppression of angiotensin II-driven aldosterone secretion by the adrenal gland. Inhibition of aldosterone secretion may depend on the degree of inhibition of angiotensin II formation in the circulation and also locally in the adrenal gland. Because the various ACE inhibitors exhibit different degrees of ACE inhibition at the tissue level, we have postulated that angiotensin II-dependent aldosterone production will be inhibited to a lesser degree by agents that have low tissue affinity for the adrenal gland. The implication of this theoretical concept for the development of hyperkalemia in patients with impaired renal function treated with ACE inhibitors is discussed.

Primary focal segmental glomerulosclerosis: clinical course and response to therapy

Primary focal segmental glomerulosclerosis (FSGS) is a lesion associated with a poor prognosis and results in end-stage renal disease after 5 to 10 years. Based on past experience, many nephrologists have considered primary FSGS a lesion that is steroid resistant and therefore are reluctant to offer steroids as treatment. Recent data, however, have demonstrated that patients with primary FSGS have a response to steroid therapy that is considerably better than had been described. Thus, it may be that nephrologists have been more "steroid reluctant" than the lesion is steroid resistant. To better understand this issue we review the clinical course and response to therapy in patients with primary FSGS.

Response to inhibition of angiotensin-converting enzyme in human immunodeficiency virus-associated nephropathy: a case report

The most common chronic nephropathy seen with human immunodeficiency virus (HIV) infection is characterized by heavy proteinuria and rapid deterioration of renal function. We here report the findings in an HIV-seropositive patient with nephrotic-range proteinuria and biopsy-proven HIV-associated nephropathy treated with the angiotensin-converting enzyme (ACE) inhibitor, fosinopril. During treatment periods, the patient demonstrated a significant decrement in 24-hour urinary protein excretion without change in renal function. The patient acted as her own control. After discontinuation of the drug, the 24-hour protein excretion deteriorated to pretreatment levels. ACE inhibition has been reported to decrease proteinuria and to have a beneficial influence on the progression of renal failure in diabetic and nondiabetic renal disease. To date, there is no known therapy for HIV-associated nephropathy. Our preliminary results in this patient suggest the need for long-term studies to assess whether this form of therapy can improve proteinuria over longer periods and, at the same time, ameliorate the progressive form of nephropathy seen in selected HIV-seropositive patients.

Dissociation between the course of the hemodynamic and antiproteinuric effects of angiotensin I converting enzyme inhibition

Angiotensin I converting enzyme inhibition (ACEi) has been shown to lower urinary protein excretion in human renal disease. The mechanism of this antiproteinuric effect is hypothesized to be mediated by changes in renal hemodynamics. However, clinical studies suggest that the effect on renal hemodynamics is fully established immediately after the start of treatment, whereas others show the antiproteinuric effect to reach maximum only after several weeks. To clarify this issue we studied the course of renal hemodynamics, blood pressure and proteinuria during 28 days of ACEi (enalapril 10 mg oid) in nine patients with proteinuria due to non-diabetic renal disease. The effect of ACEi on blood pressure and renal hemodynamics was already maximal within few hours after start of treatment, and remained stable thereafter: MAP was lowered with 8.6 +/- 1.9%, 10.6 +/- 2.1%, 12.8 +/- 2.3% and 12.9 +/- 2.5%, while FF fell 23.0 +/- 2.0%, 17.0 +/- 2.6%, 16.8 +/- 2.8% and 15.9 +/- 4.0% on days 1, 7, 14 and 28 of ACEi, respectively. However, the antiproteinuric effect only gradually reached its maximum on day 28. Urinary protein excretion decreased with 10.9 +/- 6.1%, 32.7 +/- 6.2%, 46.3 +/- 2.5% and 54.0 +/- 2.5% on days 1, 7, 14 and 28 of ACEi, respectively. After drug withdrawal all parameters returned towards baseline. We conclude that a dissociation occurs in the course of the ACEi induced effects on hemodynamics and urinary protein excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II local hyperreactivity in the progression of IgA nephropathy

Immunologic and hemodynamic factors are likely to work in synergism in the progression of immunoglobulin A nephropathy (IgAN) toward sclerosis. The local activation of the renin-angiotensin system may be one the most relevant mechanisms. We investigated the hemodynamic effects of the acute administration of angiotensin-converting enzyme inhibitor (ACEI) (captopril 50 mg). The glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF) were measured by 51Cr-EDTA and 125I hippurate clearances. The correspondent filtration fractions (FFs) in basal conditions and after administration of ACEI were calculated, then the changes in FF (delta FF and % delta FF) were determined. We studied 27 IgAN patients. Eighteen patients had normal renal function (GFR, 112 +/- 19 mL/min/1.73 m2) and nine had moderate renal impairment (GFR, 54 +/- 13 mL/min/1.73 m2). Sixteen patients had proteinuria > or = 0.5 g/d. In addition, 12 glomerulonephritis control cases and eight healthy subjects were investigated. After the administration of ACEI in healthy subjects we observed slight modifications in the GFR, a significant increase in the ERPF (P < 0.005), and a significant decrease in FF (P < 0.04). Similarly, in IgAN patients with normal renal function the GFR increased slightly, the ERPF increased significantly (P < 0.01), and there was a decrease in FF (P < 0.01). The delta FF and % delta FF values were not significantly different from those found in the controls. In patients with initial renal failure GFR remained unchanged, ERPF increased significantly (P < 0.005), and FF significantly decreased (P < 0.004). However, the changes in delta FF and % delta FF were significantly greater than those found in healthy controls (P < 0.01) and in IgAN patients with normal renal function (P < 0.001). IgAN patients with proteinuria levels > or = 0.5 g/d showed greater changes in delta FF and % delta FF after the administration of ACEI than patients with proteinuria levels lower than 0.5 g/d (P < 0.003 and P < 0.04, respectively) or proteinuric control cases (P < 0.05 and P < 0.01, respectively). This different response in proteinuric and nonproteinuric patients was evident even when the analysis was limited to the subgroup of IgAN patients with normal renal function. The decrease in FF consequent to an increase in the ERPF after the administration of ACEI suggests a local hyperactivity of the renin-angiotensin system in some cases of IgAN.(ABSTRACT TRUNCATED AT 400 WORDS)

Hemodynamic alterations and urinary albumin excretion in patients with essential hypertension

Salt-sensitive animals as well as patients with essential hypertension appear to have a greater propensity to develop renal disease as a consequence of hypertension. They also manifest an abnormal renal hemodynamic adaptation to changes in dietary sodium intake and blood pressure. This suggests that the two may be related. Some patients with essential hypertension manifest an increase in urinary albumin excretion (UAE). It is uncertain whether this is more common in salt-sensitive patients and whether it represents a marker for progressive renal disease. The effect of antihypertensive agents on UAE varies substantially depending on the agent used, and it is not necessarily related to the antihypertensive action. Whether antihypertensive agents that more effectively reduce UAE may also result in greater renal protective effects remains to be established.

Effects of angiotensin II receptor blockade on remnant glomerular permselectivity

This study examined the mechanisms by which angiotensin II (Ang II) receptor blockade improves glomerular barrier function in rats with reduced nephron number. Proteinuria was measured at four weeks after 5/6 renal ablation, and rats were then divided into a group which received the Ang II receptor blocker MK954 and a group which received no treatment. Studies performed one week later showed that Ang II receptor blockade reduced proteinuria without altering GFR in renal ablated rats. Micropuncture studies showed that Ang II blockade reduced both mean arterial pressure (142 +/- 7 mm Hg, ablation without treatment; 105 +/- 2 mm Hg, ablation with treatment) and glomerular transcapillary pressure (54 +/- 3 mm Hg, ablation without treatment; 43 +/- 1 mm Hg, ablation with treatment). Dextran sieving studies showed that untreated rats developed a size-selective defect characterized by increased transglomerular passage of neutral dextrans with radii 54 to 76 A and a charge-selective defect characterized by an increased transglomerular passage of anionic dextran sulfate with a radius of approximately 18 A. Ang II blockade reduced fractional clearance values for large neutral dextrans near to values observed in normal rats but had no effect on the fractional clearance of dextran sulfate (0.68 +/- 0.11, ablation without treatment; 0.66 +/- 0.08, ablation with treatment; 0.46 +/- 0.05, normal rats). These findings indicate that reducing Ang II activity improves size-selectivity without affecting charge-selectivity in injured remnant glomeruli.

Long-term beneficial effects of angiotensin-converting enzyme inhibition in patients with nephrotic proteinuria

Angiotensin-converting enzyme inhibitors (ACEI) can reduce proteinuria in diabetic and nondiabetic nephropathy. However, no studies have determined whether this antiproteinuric effect modifies the progression of renal insufficiency. We studied the evolution of 46 nondiabetic patients with nephrotic proteinuria treated with captopril for a minimum of 12 months. The follow-up period before captopril treatment was 12 to 18 months. At the end of follow-up, after captopril introduction (24.4 +/- 7.6 months), proteinuria had decreased from 6.3 +/- 2.5 to 3.9 +/- 3.1 g/24 h (P less than 0.001), with a mean decrease of 45% +/- 28%. The proteinuria decrease was higher in patients with reflux nephropathy, proteinuria associated with reduction of renal mass, inactive crescentic glomerulonephritis, nephroangiosclerosis, and IgA nephropathy, whereas patients with membranous glomerulonephritis and idiopathic focal glomerulosclerosis showed a poorer response. Patients were separated according to a proteinuria reduction greater (group A, 23 patients) or lower (group B, 23 patients) than 45% of the initial value. At the end of follow-up, renal function had not significantly changed in group A with respect to values at the start of treatment: serum creatinine (SCr) was 229 +/- 167 mumol/L (2.6 +/- 1.9 mg/dL) versus 203 +/- 97 mumol/L (2.3 +/- 1.1 mg/dL), and creatinine clearance (CrCl) was 0.80 +/- 0.52 mL/s (48 +/- 31 mL/min) versus 0.87 +/- 0.47 mL/s (52 +/- 28 mL/min). The slope of the reciprocal of Scr (1/SCr) showed a significantly beneficial change after captopril introduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal hemodynamics and reduction of proteinuria by a vasodilating beta blocker versus an ACE inhibitor

The effects of a nonselective beta-adrenergic blocking drug with beta-2 agonist activity (dilevalol 200 mg) on proteinuria and renal hemodynamics were evaluated in a double-blind crossover study versus an ACE inhibitor (enalapril 5 mg) in eight patients with glomerulonephritis, moderate renal function impairment and proteinuria greater than 1 g/24 hr. Patients were studied after a one week placebo phase while off all other medications, except steroids in a few cases, and after three weeks of treatment. A 10-day placebo washout perod was included between the various drug treatments. During each period renal hemodynamics were measured by clearance techniques, and urinary protein excretion as well as fractional clearance of albumin and IgG were determined. Both drugs reduced mean arterial pressure and proteinuria to a similar extent [mean arterial pressure: placebo 108 +/- 13 mm Hg; dilevalol 103 +/- 11 mm Hg (P less than 0.05); enalapril 103 +/- 12 mm Hg (P less than 0.05); protein excretion: placebo 5.1 +/- 4.2 g/day; dilevalol 3.3 +/- 3.0 g/day (P less than 0.05); enalapril 2.8 +/- 2.8 g/day (P less than 0.05)]. The antiproteinuric effect was greater with enalapril than dilevalol. Dilevalol reduced GFR [baseline inulin clearance: 73.3 +/- 38 ml/min/1.73 m2; after dilevalol: 63.3 +/- 28 ml/min/1.73 m2 (P less than 0.05)] and the decrease of proteinuria correlated positively with the reduction of GFR. Enalapril did not significantly lower the GFR (inulin clearance during enalapril 66.8 +/- 23 ml/min/1.73 m2) and the reduction of proteinuria did not correlate with the lowering of the GFR.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of enalapril and atenolol on proteinuria and renal haemodynamics in non-diabetic renal disease

OBJECTIVE

To compare the antihypertensive, renal haemodynamic and antiproteinuric effect of enalapril and atenolol in patients with proteinuria of non-diabetic origin.

DESIGN

Prospective, double blind, randomised 16 week study after a pretreatment period of at least three weeks.

SETTING

Outpatient nephrology and hypertension unit.

PATIENTS

27 patients with proteinuria (greater than 300 mg protein/day) of non-diabetic origin, moderately impaired renal function (creatinine clearance 30-90 ml/min), and a pretreatment diastolic blood pressure of greater than 80 mm Hg.

INTERVENTIONS

Treatment with enalapril (10 mg/day, adjusted between 5 and 40 mg, if necessary) or atenolol (50 mg/day, adjusted between 25 and 100 mg if necessary) titrated against a target fall in diastolic blood pressure to less than 95 mm Hg or of greater than 10 mm Hg, or both.

MAIN OUTCOME MEASURES

Blood pressure, renal haemodynamics, and urinary protein excretion.

RESULTS

No differences were detected between the two groups before treatment. The falls in systolic and diastolic blood pressures during treatment were not significantly different between both groups. Proteinuria fell slightly with atenolol but significantly more with enalapril (mean change -0.38 (95% confidence interval -0.78 to 0.03) v -1.2 (-1.70 to -0.69) g/day respectively, p less than 0.02) as did filtration fraction (mean change -1.8 (-2.9 to -0.7) v -3.8 (-4.9 to -2.8)% respectively. Serum potassium concentration increased with enalapril (mean change 0.63 (SD 0.51) v 0.19 (0.47) mmol/l, p less than 0.05).

CONCLUSIONS

Enalapril lowers proteinuria more than atenolol in patients with non-diabetic renal disease despite a similar blood pressure lowering effect of both drugs, and its antiproteinuric effect seems to be associated with the characteristic renal haemodynamic effect of angiotensin converting enzyme inhibitors.