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

Rationale for the use of a fixed-dose combination in the management of hypertension: efficacy and tolerability of lercanidipine/enalapril

Hypertension, a significant factor in the development of cerebrovascular disorders, heart disease and renal failure, is a common disorder worldwide. Despite the availability of a wide range of antihypertensive agents, almost two-thirds of hypertensive patients have poorly controlled blood pressure (BP). Numerous clinical trials have shown that most patients require at least two antihypertensive agents to achieve adequate BP control and associated significant reductions in cardiovascular morbidity and mortality. Combination therapy using two drugs with different, complementary mechanisms of action achieves better efficacy and tolerability outcomes than treatment with either component drug alone. When such a combination is administered as a fixed-dose formulation, other benefits, such as improved compliance and potentially lower costs, are also likely. The good efficacy and tolerability of the combination of a calcium channel antagonist and an angiotensin-converting enzyme inhibitor is well established, and this combination is recommended by European Society of Hypertension/European Society of Cardiology guidelines as a first choice in high-risk hypertensive patients, including those with type 2 diabetes mellitus. Lercanidipine/enalapril is a promising example of a fixed-dose combination of these drug classes. In clinical trials in hypertensive patients, including those with type 2 diabetes, lercanidipine/enalapril improved BP to a greater extent than either drug as monotherapy (in patients who were previous non-responders to lercanidipine or enalapril) or the combination of lercanidipine/hydrochlorothiazide, and was equally well tolerated. Further studies are required to evaluate the cardiovascular protective effects of lercanidipine/enalapril.

Blood pressure level and kidney disease progression: do we really need to go to 130/80 mm Hg?

Current guidelines recommend a blood pressure goal of less than 130/80 mm Hg in patients with chronic kidney disease. Considerable epidemiologic observational data, post hoc analyses of clinical trials, and meta-analyses support this goal, particularly in patients with proteinuria. Although prospective clinical trials have not shown a clear benefit, recent data indicate that a longer duration of follow-up may be needed to assess the effects of different blood pressure goals. While we await the results of several ongoing and planned studies in this area, the current recommendations of a blood pressure goal less than 130/80 mm Hg appear reasonable.

Early change in proteinuria as a surrogate outcome in kidney disease progression: a systematic review of previous analyses and creation of a patient-level pooled dataset

BACKGROUND

Proteinuria is a candidate surrogate end point for randomized controlled trials (RCTs) in chronic kidney disease (CKD). There is a reasonably sound biological basis for this hypothesis, but only preliminary empirical evidence currently exists.

METHODS

A systematic review and creation of a patient-level dataset of randomized controlled trials (RCTs) in CKD that reported changes in proteinuria and assessed progression of kidney disease as defined by dialysis, transplantation, death, or changes in GFR or creatinine were performed.

RESULTS

Systematic review. Seventy RCTs met the eligibility criteria; 17 eligible RCTs contained analyses of proteinuria as a predictor of outcomes; 15 RCTs concluded that greater proteinuria was associated with adverse outcomes. A majority were studies of diabetic or hypertensive kidney disease and tested renin-angiotensin system blockade. Definitions of predictor and outcome variables were too variable to conduct a meta-analysis of group data. Database creation. Over 4 years was required to create the patient-level dataset. The final dataset included 34 studies and > 9000 patients with a variety of CKD types and interventions.

CONCLUSIONS

There are a relatively small number of RCTs designed to rigorously test therapies for kidney disease progression. Current analyses of change in proteinuria as a predictor of CKD progression are heterogeneous and incomplete, indicating further evaluation in a pooled individual patient-level database is necessary to advance knowledge in this field.

Intensive blood-pressure control in hypertensive chronic kidney disease

BACKGROUND

In observational studies, the relationship between blood pressure and end-stage renal disease (ESRD) is direct and progressive. The burden of hypertension-related chronic kidney disease and ESRD is especially high among black patients. Yet few trials have tested whether intensive blood-pressure control retards the progression of chronic kidney disease among black patients.

METHODS

We randomly assigned 1094 black patients with hypertensive chronic kidney disease to receive either intensive or standard blood-pressure control. After completing the trial phase, patients were invited to enroll in a cohort phase in which the blood-pressure target was less than 130/80 mm Hg. The primary clinical outcome in the cohort phase was the progression of chronic kidney disease, which was defined as a doubling of the serum creatinine level, a diagnosis of ESRD, or death. Follow-up ranged from 8.8 to 12.2 years.

RESULTS

During the trial phase, the mean blood pressure was 130/78 mm Hg in the intensive-control group and 141/86 mm Hg in the standard-control group. During the cohort phase, corresponding mean blood pressures were 131/78 mm Hg and 134/78 mm Hg. In both phases, there was no significant between-group difference in the risk of the primary outcome (hazard ratio in the intensive-control group, 0.91; P=0.27). However, the effects differed according to the baseline level of proteinuria (P=0.02 for interaction), with a potential benefit in patients with a protein-to-creatinine ratio of more than 0.22 (hazard ratio, 0.73; P=0.01).

CONCLUSIONS

In overall analyses, intensive blood-pressure control had no effect on kidney disease progression. However, there may be differential effects of intensive blood-pressure control in patients with and those without baseline proteinuria. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases, the National Center on Minority Health and Health Disparities, and others.)

Health-related quality of life in hypertension, chronic kidney disease, and coexistent chronic health conditions

With the increasing prevalence of hypertension, there has been a growing interest in understanding the health-related quality of life (HRQOL) of patients with hypertension. Although hypertension is often perceived as asymptomatic, it is associated with impaired HRQOL because of complications or comorbidities, awareness of the diagnosis, and adverse effects from antihypertensive medications. This article focuses on the literature published since 2000, on HRQOL in elderly hypertensive individuals as well as hypertensives with co-existent diseases, including chronic kidney disease, cardiovascular disease, and diabetes mellitus. Most of the studies found that hypertensive individuals with co-existent co-morbidities tend to have lower HRQOL than those with hypertension alone, and identified the number of co-morbid illnesses as an independent determinant of HRQOL. The most pronounced effect was noted in the physical function domains of HRQOL. Studies have also examined the effects on HRQOL of specific classes of antihypertensive drugs without specific demonstration of superiority of one drug class over another in terms of HRQOL measures. Although there is evidence in favor of angiotensin-converting enzyme-inhibition for improving renal and cardiovascular outcomes in hypertensive patients, its role in ameliorating HRQOL outcomes remains to be established.

Activation of the aldosterone/mineralocorticoid receptor system in chronic kidney disease and metabolic syndrome

Recent clinical and experimental studies have shown that aldosterone is a potent inducer of proteinuria and that mineralocorticoid receptor (MR) antagonists confer efficient antiproteinuric effects. We identified glomerular epithelial cells (podocytes) as novel targets of aldosterone; activation of MR injures podocytes possibly via oxidative stress, resulting in disruption of glomerular filtration barrier, proteinuria, and progression of chronic kidney disease. We also demonstrated that SHR/cp, a rat model of metabolic syndrome, was susceptible to podocyte injury and proteinuria. Aldosterone excess caused by adipocyte-derived aldosterone-releasing factors was suggested to underlie the nephropathy. High salt intake augmented MR activation in the kidney and exacerbated the nephropathy. Furthermore, we identified an alternative pathway of MR activation by small GTPase Rac1. RhoGDIalpha knockout mice, a model with Rac1 activation in the kidney, showed albuminuria, podocyte injury, and glomerulosclerosis. Renal injury in the knockout mice was accompanied by enhanced MR signaling in the kidney despite normoaldosteronemia, and was ameliorated by an MR antagonist, eplerenone. Moreover, Rac-specific inhibitor significantly reduced the nephropathy, concomitantly with repression of MR activation. In vitro transfection studies provided direct evidence of Rac1-mediated MR activation. In conclusion, our findings suggest that MR activation plays a pivotal role in the pathogenesis of chronic kidney disease in metabolic syndrome, and that MR may be activated both aldosterone dependently (via aldosterone-releasing factors) and independently (via Rac1). MR antagonists are promising antiproteinuric drugs in metabolic syndrome, although long-term effects on renal outcomes, mortality, and safety need to be established.

A randomized, double-blind, placebo-controlled trial of spironolactone on carotid intima-media thickness in nondiabetic hemodialysis patients

BACKGROUND AND OBJECTIVES

Hemodialysis patients (HD) display high rates of cardiac diseases and mortality. In chronic kidney disease, vascular injury leads to coronary artery disease, heart failure, and stroke. Carotid intima-media thickness (CIMT) measurements are currently widely used in randomized controlled trials (RCTs) to study the efficacy of interventions. An RCT was designed for the assessment of the safety and effectiveness of spironolactone to inhibit the progression of CIMT in HD patients as a primary outcome. Secondary outcomes included measurements of plasma potassium.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

HD patients were randomly assigned to receive 50 mg spironolactone or placebo thrice weekly after dialysis. In between dialysis sessions, plasma potassium concentrations were measured every month. Ultrasonographic measurements of CIMT were done at the beginning of the study and after 2 years.

RESULTS

Fifty-three age- and sex-adjusted patients (30 with drug and 23 with placebo) successfully completed the trial. There were no significant differences between the two groups in all profiles studied at baseline. Measurements of CIMT after 2 years showed a progression in the placebo group, whereas in the spironolactone group a significant decrease or even reversed CIMT was observed. Progression rates (mm/yr) were: common carotid, placebo: 0.06 +/- 0.07, spironolactone: 0.01 +/- 0.04; carotid bifurcation, placebo: 0.15 +/- 0.27, spironolactone: 0.0001 +/- 0.01; internal carotid, placebo: 0.10 +/- 0.12, spironolactone: -0.10 +/- 0.15. No episodes of hyperkalemia were observed, but a slight increase in plasma potassium was found in the spironolactone group.

CONCLUSIONS

Fifty milligrams of spironolactone thrice weekly significantly reduced the progression of CIMT in HD patients.

The HALT polycystic kidney disease trials: design and implementation

BACKGROUND AND OBJECTIVES

Two HALT PKD trials will investigate interventions that potentially slow kidney disease progression in hypertensive autosomal dominant polycystic kidney disease (ADPKD) patients. Studies were designed in early and later stages of ADPKD to assess the impact of intensive blockade of the renin-angiotensin-aldosterone system and level of BP control on progressive renal disease. Design, settings, participants, and measurements: PKD-HALT trials are multicenter, randomized, double-blind, placebo-controlled trials studying 1018 hypertensive ADPKD patients enrolled over 3 yr with 4 to 8 yr of follow-up. In study A, 548 participants, estimated GFR (eGFR) of >60 ml/min per 1.73 m(2) were randomized to one of four arms in a 2-by-2 design: combination angiotensin converting enzyme inhibitor (ACEi) and angiotensin receptor blocker (ARB) therapy versus ACEi monotherapy at two levels of BP control. In study B, 470 participants, eGFR of 25 to 60 ml/min per 1.73 m2 compared ACEi/ARB therapy versus ACEi monotherapy, with BP control of 120 to 130/70 to 80 mmHg. Primary outcomes of studies A and B are MR-based percent change kidney volume and a composite endpoint of time to 50% reduction of baseline estimated eGFR, ESRD, or death, respectively.

RESULTS

This report describes design issues related to (1) novel endpoints such as kidney volume, (2) home versus office BP measures, and (3) the impact of RAAS inhibition on kidney and patient outcomes, safety, and quality of life.

CONCLUSIONS

HALT PKD will evaluate potential benefits of rigorous BP control and inhibition of the renin-angiotensin-aldosterone system on kidney disease progression in ADPKD.

Beneficial effect of all-trans retinoic acid (ATRA) on glomerulosclerosis rats via the down-regulation of the expression of alpha-smooth muscle actin: a comparative study between ATRA and benazepril

Although ATRA is a potent renoprotective agent, relatively little is known regarding the mechanisms of its action. The present study was designed to further elucidate the mechanisms of ATRA's action to GS rats and compare that with the beneficial effect of benazepril. Male SD rats weighting 160 to 200g were used in this study. GS was induced by unilateral nephrectomy and intravenous injection of adriamycin (6mg/kg). They were divided randomly 20 ones per group into GS group, GS treated with ATRA (20mg/kg/day) group, and GS treated with benazepril (10mg/kg/day) group. The other 20 ones were taken as sham-operation group, injected normal saline into caudal vein. 12weeks later, all rats were subjected to sacrifice. As expected, the GS group exhibited significant lower serum TP and Alb, and higher BUN, Cr and proteinuria than those of the sham group. Administration of ATRA or benazepril did ameliorate these above disorders of biochemical parameters in GS rats. Extensive renal damage was observed in the GS group, such as mononuclear infiltration, mesangial proliferation, focal segment glomerular sclerosis, and tubulointerstitial fibrosis. The pathological changes in both ATRA and benazepril group were alleviated remarkably. Semiquantitative GSI was used to evaluate the degree of GS in all groups. GSI was significantly higher in the GS group than in sham group. GSI decreased from 21.9+/-6.7 in the GS group to 6.9+/-2.8 in the ATRA group and 7.0+/-2.7 in benazepril group respectively. However, no significant difference in GSI between rats treated with ATRA and rats treated with benazepril was found. RT-PCR analysis revealed the renal expression of alpha-SMA mRNA was induced substantially in GS group as compared to sham group, which could be offset completely by ATRA or benazepril administration. However, expression level of alpha-SMA mRNA in GS rats treated with ATRA was identical to that in GS rats treated with benazepril. We also examined immunohistochemical staining for renal alpha-SMA, TGF-beta1, Col IV, and FN in this model. Weak staining was observed in some glomerulus, mesangial cells, and tubular interstitium of sham rats. Staining was markedly enhanced in the majority of glomerulus, mesangial cells, and tubular interstitium of untreated GS rats. Compared with untreated GS animals, intensity and extent of staining for renal alpha-SMA, TGF-beta1, Col IV, and FN were markedly reduced in glomerulus, mesangial cells, and tubular interstitium of GS rats treated with either ATRA or benazepril. However, no significant differences existed between ATRA and benazepril with respect to the glomerular and tubulointerstitial staining scores. Interestingly, our data documented some differences of therapeutic capacities between ATRA and benazepril. In comparison with benazepril, ATRA exerted no improvement in hypoproteinemia, but more significant decrease in serum Cr level in GS rats. The reasons leading to these variations are unclear. Whatever they are, the properties of down-regulate inflammatory/proliferative programs may make ATRA an attractive potential candidate for future therapeutic use in kidney disease.

Interstitial expression of angiotensin II and AT1 receptor are increased in patients with progressive glomerulopathies

In animal models, interstitial angiotensin II (ang II) and AT1 receptor (AT1R) are key mediators of renal inflammation and fibrosis in progressive chronic nephropathies. We hypothesized that these molecules were overexpressed in patients with progressive glomerulopathies. In this observational retrospective study, we described the expression of ang II and AT1R by immunohistochemistry in kidney biopsies of 7 patients with minimal change disease (MCD) and in 25 patients with progressive glomerulopathies (PGPs). Proteinuria, serum albumin, and serum creatinine were not statistically different between MCD and PGP patients. Total expression of ang II and AT1R was not statistically different between MCD (108.7+/-11.5 and 73.2+/-13.6 cells/mm(2), respectively) and PGN patients (100.7+/-9.0 and 157.7+/-13.8 cells/mm(2), respectively; p>0.05). Yet, interstitial expression of ang II and AT1R (91.6+/-16.0 and 45.6+/-5.4 cells/mm(2), respectively) was higher in patients with PGN than in those with MCD (22.0+/-4.1 and 17.9+/-2.9 cells/mm(2), respectively, p<0.05), as was the proportion of interstitial fibrosis (11.0+/-0.7% versus 6.1+/-1.2%, p<005). In patients with MCD, ang II and AT1R expressions predominate in the tubular compartment (52% and 36% of the positive cells, respectively). In those with PGP, the interstitial expression of ang II and AT1R predominates (58% and 45%, respectively). In conclusion, interstitial expression of ang II and AT1R is increased in patients with progressive glomerulopathies. The relationship of these results and interstitial fibrosis and disease progression in humans warrants further investigations.

The RAAS in the pathogenesis and treatment of diabetic nephropathy

Angiotensin II and other components of the renin-angiotensin-aldosterone system (RAAS) have a central role in the pathogenesis and progression of diabetic renal disease. A study in patients with type 1 diabetes and overt nephropathy found that RAAS inhibition with angiotensin-converting-enzyme (ACE) inhibitors was associated with a reduced risk of progression to end-stage renal disease and mortality compared with non-RAAS-inhibiting drugs. Blood-pressure control was similar between groups and proteinuria reduction was responsible for a large part of the renoprotective and cardioprotective effect. ACE inhibitors can also prevent microalbuminuria in patients with type 2 diabetes who are hypertensive and normoalbuminuric; in addition, ACE inhibitors are cardioprotective even in the early stages of diabetic renal disease. Angiotensin-II-receptor blockers (ARBs) are renoprotective (but not cardioprotective) in patients with type 2 diabetes and overt nephropathy or microalbuminuria. Studies have evaluated the renoprotective effect of other RAAS inhibitors, such as aldosterone antagonists and renin inhibitors, administered either alone or in combination with ACE inhibitors or ARBs. An important task for the future will be identifying which combination of agents achieves the best renoprotection (and cardioprotection) at the lowest cost. Such findings will have major implications, particularly in settings where money and facilities are limited and in settings where renal replacement therapy is not available and the prevention of kidney failure is life saving.

The role of renin angiotensin system inhibition in kidney repair

Chronic kidney diseases share common pathogenic mechanisms that, independently from the initial injury, lead to glomerular hyperfiltration, proteinuria, and progressive renal scarring and function loss. Inhibition of the renin angiotensin system (RAS) has been consistently found to reduce or halt the progressive deterioration of renal function through reduction of blood pressure and proteinuria, the two main determinants of renal function decline. In few instances, RAS inhibition may even promote amelioration of the glomerular filtration rate. Animal data suggest that chronic therapy with angiotensin-converting enzyme inhibitors or angiotensin II receptor type I blockers promotes regression of glomerulosclerosis, even in later phases of the disease. In humans, studies investigating the effect of angiotensin II inhibition on renal structural changes have shown inconsistent results, possibly due to small numbers and/or short duration of follow-up. Whether regression of glomerulosclerosis relies on a direct regenerative effect of RAS inhibition or on spontaneous kidney self-repair after the injury has been removed is still unknown. Improved understanding of mechanisms that promote renal regeneration may help in designing specific therapies to prevent the development of end-stage renal disease. This is a desirable goal, considering the economic burden of chronic kidney diseases and their effect on morbidity and mortality.

Dual blockade of the renin-angiotensin-aldosterone system in cardiac and renal disease

PURPOSE OF REVIEW

Renin-angiotensin-aldosterone system (RAAS) blockade improves outcome in cardiovascular disease (CVD) and chronic kidney disease (CKD), but the residual risk during monotherapy RAAS blockade remains very high. This review discusses the place of dual RAAS blockade in improving these outcomes.

RECENT FINDINGS

The combination of angiotensin-converting enzyme inhibitor (ACEI) with angiotensin II type 1 receptor blocker (ARB) generally had a better antihypertensive and antiproteinuric effect than monotherapy in many studies, but is also associated with more adverse effects. Unfortunately, the effect on hard renal and cardiovascular endpoints is not unequivocal. The combination of ACEI (or ARB) with aldosterone blockade has long-term benefits in heart failure, and an added effect on proteinuria in CKD, but data on hard renal endpoints are lacking. Dual blockade including renin inhibition has added antiproteinuric effects, but studies to gather long-term data are still under way. Available strategies to optimize the effect of monotherapy RAAS blockade include dose titration and correction of volume excess. Whether dual blockade has better efficacy and/or fewer adverse effects than optimized monotherapy has not been investigated.

SUMMARY

Several options are available to increase the effect of monotherapy RAAS blockade. For proteinuric CKD, these can be combined in a stepwise approach aimed at maximal proteinuria reduction; this includes dual blockade for patients with persistent proteinuria during optimized monotherapy RAAS blockade. Long-term randomized studies, however, are needed to support the benefits of dual blockade for long-term renal and cardiovascular outcome in CKD.

Effects of Bupleurum falcatum and its combination with an angiotensin II receptor blocker on cytokine and chemokine expression in human mesangial cells

This study aimed to investigate the inhibitory effect of Bupleurum falcatum and its combination with angiotensin II receptor blocker (ARB) on cytokine and chemokine production in cultured human mesangial cells. Human mesangial cells were isolated and cultured in Dulbecco's modified Eagle's medium culture medium. Bupleurum falcatum, ARB, and the combination of the two were added to human mesangial cells. Cytokine and chemokine levels were analysed using an enzyme-linked immunosorbent assay. There were no significant differences in the expression of IL-1ss, IL-2 or TNF-a between controls and the experimental groups. However, IL-11 and monocyte chemoattractant protein-1 (MCP-1) levels were significantly reduced in response to ARB, Bupleurum falcatum, or their combination when compared with controls. IL-8 expression was reduced significantly only in cells treated with ARB. Both Bupleurum falcatum and ARB treatments alone reduced the cytokine concentration, but there was not a stronger reduction when the two drugs were combined. It was shown that Bupleurum falcatum inhibited cytokine production in human mesangial cells. However, there were no additive effects on the suppression of cytokine production when Bupleurum falcatum was combined with ARB. Further studies are needed to elucidate the renoprotective effects of Bupleurum falcatum.

Early recognition and prevention of chronic kidney disease

Chronic kidney disease is a common disorder and its prevalence is increasing worldwide. Early diagnosis on the basis of presence of proteinuria or reduced estimated glomerular filtration rate could permit early intervention to reduce the risks of cardiovascular events, kidney failure, and death that are associated with chronic kidney disease. In developed countries, screening for the disorder is most efficient when targeted at high-risk groups including elderly people and those with concomitant illness (such as diabetes, hypertension, or cardiovascular disease) or a family history of chronic kidney disease, although the role of screening in developing countries is not yet clear. Effective strategies are available to slow the progression of chronic kidney disease and reduce cardiovascular risk. Treatment of high blood pressure is recommended for all individuals with, or at risk of, chronic kidney disease. Use of angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers is preferred for patients with diabetic chronic kidney disease or those with the proteinuric non-diabetic disorder. Glycaemic control can help prevent the onset of early stages of chronic kidney disease in individuals with diabetes. Use of statins and aspirin is beneficial for most patients with chronic kidney disease who are at high cardiovascular risk, although research is needed to ascertain how to best prevent cardiovascular disease in this cohort. Models of care that facilitate delivery of the many complex aspects of treatment simultaneously could enhance management, although effects on clinical outcomes need further assessment. Novel clinical methods to better identify patients at risk of progression to later stages of chronic kidney disease, including kidney failure, are needed to target management to high-risk subgroups.

Renal outcomes with different fixed-dose combination therapies in patients with hypertension at high risk for cardiovascular events (ACCOMPLISH): a prespecified secondary analysis of a randomised controlled trial

BACKGROUND

The Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH) trial showed that initial antihypertensive therapy with benazepril plus amlodipine was superior to benazepril plus hydrochlorothiazide in reducing cardiovascular morbidity and mortality. We assessed the effects of these drug combinations on progression of chronic kidney disease.

METHODS

ACCOMPLISH was a double-blind, randomised trial undertaken in five countries (USA, Sweden, Norway, Denmark, and Finland). 11 506 patients with hypertension who were at high risk for cardiovascular events were randomly assigned via a central, telephone-based interactive voice response system in a 1:1 ratio to receive benazepril (20 mg) plus amlodipine (5 mg; n=5744) or benazepril (20 mg) plus hydrochlorothiazide (12.5 mg; n=5762), orally once daily. Drug doses were force-titrated for patients to attain recommended blood pressure goals. Progression of chronic kidney disease, a prespecified endpoint, was defined as doubling of serum creatinine concentration or end-stage renal disease (estimated glomerular filtration rate <15 mL/min/1.73 m(2) or need for dialysis). Analysis was by intention to treat (ITT). This trial is registered with ClinicalTrials.gov, number NCT00170950.

FINDINGS

The trial was terminated early (mean follow-up 2.9 years [SD 0.4]) because of superior efficacy of benazepril plus amlodipine compared with benazepril plus hydrochlorothiazide. At trial completion, vital status was not known for 143 (1%) patients who were lost to follow-up (benazepril plus amlodipine, n=70; benazepril plus hydrochlorothiazide, n=73). All randomised patients were included in the ITT analysis. There were 113 (2.0%) events of chronic kidney disease progression in the benazepril plus amlodipine group compared with 215 (3.7%) in the benazepril plus hydrochlorothiazide group (HR 0.52, 0.41-0.65, p<0.0001). The most frequent adverse event in patients with chronic kidney disease was peripheral oedema (benazepril plus amlodipine, 189 of 561, 33.7%; benazepril plus hydrochlorothiazide, 85 of 532, 16.0%). In patients with chronic kidney disease, angio-oedema was more frequent in the benazepril plus amlodipine group than in the benazepril plus hydrochlorothiazide group. In patients without chronic kidney disease, dizziness, hypokalaemia, and hypotension were more frequent in the benazepril plus hydrochlorothiazide group than in the benazepril plus amlodipine group.

INTERPRETATION

Initial antihypertensive treatment with benazepril plus amlodipine should be considered in preference to benazepril plus hydrochlorothiazide since it slows progression of nephropathy to a greater extent.

FUNDING

Novartis.

Can we slow the progression of chronic kidney disease?

PURPOSE OF REVIEW

Childhood chronic kidney disease usually progresses towards end-stage renal failure once a critical impairment of renal function has occurred. This process is largely independent of the underlying renal disease. Recent clinical trials have provided evidence that the progressive course of chronic kidney disease can be slowed substantially by pharmacological intervention.

RECENT FINDINGS

Hypertension and proteinuria are the most important independent risk factors for renal disease progression in both adult and pediatric nephropathies. Pharmacological blockade of the renin-angiotensin system provides efficient control of blood pressure and proteinuria, and superior long-term renoprotection compared with other antihypertensive agents. Recent pediatric evidence supports the renoprotective efficacy of tight blood pressure control aiming for the low-normal range. In addition, promising preliminary findings suggest an additional renoprotective potential by correction of metabolic acidosis and hyperuricemia and by administration of antiproliferative and antioxidative drugs.

SUMMARY

Pharmacological renoprotection currently focuses on antihypertensive and antiproteinuric treatment by blockade of the renin-angiotensin system. Intensified blood pressure control can improve 5-year renal survival by 35% in children with chronic kidney disease. Additional complementary strategies under current clinical evaluation bear potential to improve renal survival even further.

Inflammation and cachexia in chronic kidney disease

Chronic inflammation is associated with cachexia and increased mortality risk in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Inflammation suppresses appetite and causes the loss of protein stores. In CKD patients, increased serum levels of pro-inflammatory cytokines may be caused by reduced renal function, volume overload, oxidative or carbonyl stress, decreased levels of antioxidants, increased susceptibility to infection in uremia, and the presence of comorbid conditions. Cachexia is brought about by the synergistic combination of a dramatic decrease in appetite and an increase in the catabolism of fat and lean body mass. Pro-inflammatory cytokines act on the central nervous system to alter appetite and energy metabolism and to provide a signal-through the nuclear factor-kappaB and ATP-ubiquitin-dependent proteolytic pathways-that causes muscle wasting. Further research into the molecular pathways leading to inflammation and cachexia may lead to novel therapeutic therapies for this devastating and potentially fatal complication of chronic disease.

Aldosterone: effects on the kidney and cardiovascular system

Aldosterone, a steroid hormone with mineralocorticoid activity, is mainly recognized for its action on sodium reabsorption in the distal nephron of the kidney, which is mediated by the epithelial sodium channel (ENaC). Beyond this well-known action, however, aldosterone exerts other effects on the kidney, blood vessels and the heart, which can have pathophysiological consequences, particularly in the presence of a high salt intake. Aldosterone is implicated in renal inflammatory and fibrotic processes, as well as in podocyte injury and mesangial cell proliferation. In the cardiovascular system, aldosterone has specific hypertrophic and fibrotic effects and can alter endothelial function. Several lines of evidence support the existence of crosstalk between aldosterone and angiotensin II in vascular smooth muscle cells. The deleterious effects of aldosterone on the cardiovascular system require concomitant pathophysiological conditions such as a high salt diet, increased oxidative stress, or inflammation. Large interventional trials have confirmed the benefits of adding mineralocorticoid-receptor antagonists to standard therapy, in particular to angiotensin-converting-enzyme inhibitor and angiotensin II receptor blocker therapy, in patients with heart failure. Small interventional studies in patients with chronic kidney disease have shown promising results, with a significant reduction of proteinuria associated with aldosterone antagonism, but large interventional trials that test the efficacy and safety of mineralocorticoid-receptor antagonists in chronic kidney disease are needed.

Hypertension in autosomal dominant polycystic kidney disease

Hypertension is common and occurs in a majority of autosomal dominant polycystic kidney disease (ADPKD) patients before the loss of kidney function. Hypertension relates to progressive kidney enlargement and is a significant independent risk factor for progression to ESRD. The pathogenesis of hypertension in ADPKD is complex and dependent on many factors that influence each other. Pkd1 and Pkd2 expression levels are highest in the major vessels and are present in the cilia of endothelial cells and in vascular smooth muscle cells. Decreased or absent polycystin 1 or 2 expression is associated with abnormal vascular structure and function. Pkd1/Pkd2 deficiency results in reduced nitric oxide (NO) levels, altered endothelial response to shear stress with attenuation in vascular relaxation. Ten percent to 20% of ADPKD children show hypertension and the majority of adults are hypertensive before any loss of kidney function. Cardiac abnormalities such as left ventricular hypertrophy and carotid intimal wall thickening are present before the development of hypertension in ADPKD. The activation of the renin-angiotensin-aldosterone system occurs in ADPKD because of decreased NO production as well as bilateral cyst expansion and intrarenal ischemia. With increasing cyst size, further activation of the RAAS occurs, blood pressure increases, and a vicious cycle ensues with enhanced cyst growth and hypertension ultimately leading to ESRD. The inhibition of the angiotensin aldosterone system is possible with angiotensin converting enzyme inhibitors and angiotensin receptor blockers. However, interventional studies have not yet shown benefit in slowing progression to renal failure in ADPKD. Currently, large multicenter studies are being performed to determine the beneficial effects of RAAS inhibition both early and late in ADPKD.

Randomized, double-blind, controlled study of losartan in children with proteinuria

BACKGROUND AND OBJECTIVES

No large, randomized, double-blind trials in children with proteinuria treated with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers have previously been reported.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This 12-week, double-blind, multinational study investigated the effects of losartan 0.7 to 1.4 mg/kg per day compared with placebo (normotensive stratum) or amlodipine 0.1 to 0.2 mg/kg per day up to 5 mg/d (hypertensive stratum) on proteinuria (morning-void urinary protein-creatinine ratio, baseline > or =0.3 g/g) in 306 children up to 17 years of age.

RESULTS

Twelve weeks of treatment with losartan significantly reduced proteinuria compared with amlodipine/placebo: losartan -35.8% (95% confidence interval: -27.6% to -43.1%) versus amlodipine/placebo 1.4% (95% confidence interval: -10.3% to 14.5%), P < or = 0.001. Significance remained after adjustment for differences across treatment groups in change in BP (losartan produced incremental systolic and diastolic BP reductions versus amlodipine of 5.4 and 4.6 mmHg, respectively; and versus placebo of 3.8 and 4.0 mmHg, respectively). Proteinuria reduction was consistently observed in the normotensive (-34.4% losartan; 2.6% placebo) and hypertensive (-41.5% losartan; 2.4% amlodipine) strata, and in all prespecified subgroups, including age, gender, race, Tanner stage, weight, prior therapy with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, as well as among the most common etiologies of proteinuria. Adverse event incidence was low and comparable in all groups.

CONCLUSIONS

Losartan significantly lowered proteinuria and was well tolerated after 12 weeks in children aged 1 to 17 years with proteinuria with or without hypertension, a population that has not previously been rigorously studied.

Effects of atorvastatin on arterial stiffness in chronic kidney disease: a randomised controlled trial

AIM

Central pulse pressure and measures of arterial stiffness (augmentation index (AIx) and aortic pulse wave velocity (PWV)) predict morbidity and mortality in patients with stage 2-4 chronic kidney disease (CKD). Although statin therapy may be of vascular benefit in patients with CKD, the long-term effect of statins on central pulse pressure and arterial stiffness has not been assessed in this patient population. Hence, the aim of this study was to assess the long-term effects of atorvastatin on arterial stiffness and central blood pressure in patients with CKD.

METHODS

We enrolled 37 patients with serum creatinine levels > 1.36 mg/dL into a randomized, double blind trial. Patients were allocated to receive 10 mg of atorvastatin per day (19) or placebo (18) for three years. Aortic PWV, AIx, estimated central and brachial blood pressures and were determined every nine months.

RESULTS

At baseline, there were no significant differences in aortic PWV, AIx, central or brachial blood pressures between atorvastatin-treated and placebo-treated patients. During the trial, aortic PWV significantly (p=0.05) increased in placebo-treated, but not (p=0.10) in atorvastatin-treated patients (0.51+/-0.95 vs. 0.30+/-0.75 m/sec/yr; p=0.48). This represented a 41% (but not statistically significant) slowing of the rate of increase in aortic stiffness. There were no significant changes between groups in the rate of change of AIx (atorvastatin -0.15+/-5.65 vs. placebo 0.39+/-5.38%/yr, p=0.53) or central pulse pressure (atorvastatin -2.32+/-7.46 vs. placebo -0.36+/-6.64 mmHg/yr p= 0.61).

CONCLUSION

In patients with CKD arterial stiffness measured by aortic PWV showed a significant increase over time in placebo-treated patients but not in atorvastatin-treated patients.

Design and methods of a strategic outcome study for chronic kidney disease: Frontier of Renal Outcome Modifications in Japan

BACKGROUND

The continuous increase in the number of people requiring dialysis is a major clinical and socioeconomical issue in Japan and other countries. This study was designed to encourage chronic kidney disease (CKD) patients to consult a physician, enhance cooperation between nephrologists and general practices, and prevent the progression of kidney disease.

METHODS

Subjects comprise CKD patients aged between 40 and 74 years consulting a general physician, and patients in CKD stage 3 with proteinuria and diabetes or hypertension. This trial is a stratified open cluster-randomized study with two intervention groups: group A (weak intervention) and group B (strong intervention). We have recruited 49 local medical associations (clusters) in 15 different prefectures, which were classified into four regions (strata) based on the level of increase rate of dialysis patients. The patients in group A clusters were instructed initially to undergo treatment in accordance with the current CKD treatment guide, whereas patients in group B clusters were not only instructed in the same fashion but also received support from an information technology (IT)-based system designed to help achieve the goals of CKD treatment, consultation support centers, and consultations by dietitians visiting the local general practice offices. We assessed the rates of continued consultation, collaboration between general practitioners and nephrologists, and progression of CKD (as expressed by CKD stage).

CONCLUSION

Through this study, filling the evidence-practice gap by facilitating effective communication and supporting general physicians and nephrologists, we will establish a CKD care system and decrease the number of advanced-stage CKD patients.

Angiotensin-converting enzyme inhibitors versus angiotensin receptor blockers for diabetic nephropathy: a retrospective comparison

INTRODUCTION

There are no adequate head-to-head comparisons of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB) in type 2 diabetic patients in spite of some interesting attempts. Furthermore, there are no adequate studies about the effects of ACE inhibitors in type 2 diabetic patients, who are the great majority of diabetic individuals. This study has retrospectively compared the effects of ACE inhibitors and ARBs used to treat diabetic nephropathy in a group of type 2 diabetic subjects.

DESIGN AND METHODS

Patients (n=154) were treated with ACE inhibitors (mean age 59.5+/-13.3 years, 52.6% were male). Eighty-five patients had been treated with ARBs from 1999 until now (mean age 62.6+/-10.9 years, 56.0% were male, differences not significant). Kaplan-Meier survival analysis was used to calculate survival before reaching end-stage renal disease (ESRD) (glomerular filtration < 15 ml/min, stage V of renal disease as defined by KDOQI clinical guidelines) or starting renal replacement therapy. Only patients treated for more than six months were included in the survival analysis. Comparison of survival was made at three, five and seven years after starting treatment.

RESULTS

Pre-ESRD survival was 91.9% at three years, 81.6% at five years and 61.9% at seven years of follow-up for patients treated with ACE inhibitors. For patients treated with ARBs, pre-ESRD survival was 95.3% at three years, 82.1% at five years and 78.2% at seven years of follow-up (p=0.02, log-rank test). At 36 months, the comparative odds ratio for having started renal replacement therapy or reaching end-stage renal failure was 0.246 (95% confidence interval 0.114-0.531, p<0.001 for chi-square and likelihood ratio tests). The risk for the ARB cohort was 0.682 (95% confidence interval 0.578-0.804), meanwhile for ACE inhibitor patients it was 2.768 (95% confidence interval 1.481-5.172).

CONCLUSIONS

The effects of ACE inhibitors and ARBs seem to be different, favouring the use of ARBs. These results may have been influenced by the different circumstances when each kind of drug was indicated, since ARBs were used with the specific recommendations for control of blood pressure in diabetic patients. An earlier referral of these patients may also have had some effect on these results. The need for a well-designed prospective study on type 2 diabetic patients with heavy proteinuria is warranted.

Reinventing the ACE inhibitors: some old and new implications of ACE inhibition

Since their inception, angiotensin-converting enzyme (ACE) inhibitors have been used as first-line therapy for the treatment of cardiovascular and renal diseases. They restore the balance between the vasoconstrictive salt-retentive and hypertrophy-causing peptide angiotensin II (Ang II) and bradykinin, a vasodilatory and natriuretic peptide. As ACE is a promiscuous enzyme, ACE inhibitors alter the metabolism of a number of other vasoactive substances. ACE inhibitors decrease systemic vascular resistance without increasing heart rate and promote natriuresis. They have been proven effective in the treatment of hypertension, and reduce mortality in congestive heart failure and left ventricular dysfunction after myocardial infarction. They inhibit ischemic events and stabilize plaques. Furthermore, they delay the progression of diabetic nephropathy and neuropathy and act as antioxidants. Ongoing studies have elucidated protective roles for them in both memory-related disorders and cancer. Lastly, N- and C-domain selective ACE inhibitors have led to new uses for ACE inhibitors.

Proteinuria and clinical outcomes in hypertensive patients

This narrative review focuses on outcomes related to proteinuria in hypertension (HT), and also examines the role of current and future therapeutic strategies. Proteinuria is an independent marker of renal and cardiovascular (CV) disease in hypertensive populations, particularly in high-risk groups such as diabetic patients. Effective blood pressure (BP) control and proteinuria management are associated with significant improvements in the risk of key adverse outcomes, although a causative relationship needs careful assessment. Available antihypertensives have varying effects on proteinuria reduction. Drugs affecting the renin system offer antiproteinuric and renoprotective effects that are probably at least partially independent of their BP effects. Economic evaluations of these interventions confirm their cost-saving benefits relative to other antihypertensives, but outcomes-based research is needed in some settings.

Relation of baseline presence and severity of renal disease to long-term mortality in persons with known stroke

BACKGROUND

Little is known about the long-term prognostic impact of baseline chronic kidney disease (CKD) on outcomes after stroke. We assessed the association of diagnosis and severity of baseline CKD with risk of mortality among persons with a history of stroke.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) a nationally representative sample of US adults were analyzed. The study population consisted of 425 individuals aged > or =55 years with a baseline history of stroke followed-up from NHANES III survey participation (1988-1994) through mortality assessment in 2000. CKD outcomes were glomerular filtration rate (GFR) <60 mL/min/1.73 m(2) and urinary albumin to creatinine ratio (UACR) >30 mg/g of creatinine. CKD severity was categorized per national guidelines. Proportional hazard regression (Cox) was utilized to explore the independent relationship between CKD vs. all-cause and cardiovascular mortality after adjusting for confounders.

RESULTS

Among the cohort, 55.8% were female, 77.3% aged > or =65 years. Baseline serum creatinine was higher among persons with known stroke who later died vs. remained alive (p<0.01). Multivariable models showed that persons with low GFR (HR, 1.87 95% CI=1.30-2.68), CKD stages 1-2 (HR 1.84; 95% CI=1.06-3.20), 3 (HR 2.58; 95% CI=1.54-4.32), and 4-5 (HR 5.93; 95% CI=2.31-5.20) but not elevated UACR, had an independently higher relative hazard of death compared to individuals without these conditions. Similar results were seen with cardiovascular-specific mortality.

CONCLUSIONS

Baseline CKD, even of mild severity, is an independent predictor of future mortality among persons with known stroke.

Strict blood-pressure control and progression of renal failure in children

BACKGROUND

Although inhibition of the renin-angiotensin system delays the progression of renal failure in adults with chronic kidney disease, the blood-pressure target for optimal renal protection is controversial. We assessed the long-term renoprotective effect of intensified blood-pressure control among children who were receiving a fixed high dose of an angiotensin-converting-enzyme (ACE) inhibitor.

METHODS

After a 6-month run-in period, 385 children, 3 to 18 years of age, with chronic kidney disease (glomerular filtration rate of 15 to 80 ml per minute per 1.73 m(2) of body-surface area) received ramipril at a dose of 6 mg per square meter of body-surface area per day. Patients were randomly assigned to intensified blood-pressure control (with a target 24-hour mean arterial pressure below the 50th percentile) or conventional blood-pressure control (mean arterial pressure in the 50th to 95th percentile), achieved by the addition of antihypertensive therapy that does not target the renin-angiotensin system; patients were followed for 5 years. The primary end point was the time to a decline of 50% in the glomerular filtration rate or progression to end-stage renal disease. Secondary end points included changes in blood pressure, glomerular filtration rate, and urinary protein excretion.

RESULTS

A total of 29.9% of the patients in the group that received intensified blood-pressure control reached the primary end point, as assessed by means of a Kaplan-Meier analysis, as compared with 41.7% in the group that received conventional blood-pressure control (hazard ratio, 0.65; confidence interval, 0.44 to 0.94; P=0.02). The two groups did not differ significantly with respect to the type or incidence of adverse events or the cumulative rates of withdrawal from the study (28.0% vs. 26.5%). Proteinuria gradually rebounded during ongoing ACE inhibition after an initial 50% decrease, despite persistently good blood-pressure control. Achievement of blood-pressure targets and a decrease in proteinuria were significant independent predictors of delayed progression of renal disease.

CONCLUSIONS

Intensified blood-pressure control, with target 24-hour blood-pressure levels in the low range of normal, confers a substantial benefit with respect to renal function among children with chronic kidney disease. Reappearance of proteinuria after initial successful pharmacologic blood-pressure control is common among children who are receiving long-term ACE inhibition. (ClinicalTrials.gov number, NCT00221845.)

Effects of angiotensin II receptor blockers on diabetic nephropathy

Impaired kidney function increases the risk of cardiovascular morbidity and mortality. Coexistence of hypertension and type 2 diabetes increases the risk of kidney damage, hypertension being an independent risk factor for kidney disease progression. Angiotensin II, through its inflammatory, proliferative, and thrombotic effects, adversely affects renal perfusion and increases oxidative stress, thus playing a pivotal role in kidney disease progression. Angiotensin II receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors improve markers of kidney disease and slow kidney disease progression in diabetic and nondiabetic patients; this kidney protection may be in addition to their antihypertensive activity in those with advanced proteinuric nephropathy. Key beneficial effects of ARBs and ACE inhibitors throughout the kidney disease continuum are primarily explained by blood pressure lowering effects and partially by their direct blockade of angiotensin II. Recent studies have shown that telmisartan, an ARB with high lipophilicity and the longest half-life compared with other ARBs, provides benefits on markers of cardiovascular risk, that is, microalbuminuria and slowing of early-stage nephropathy.

What do we know about chronic renal failure in young adults? II. Adult outcome of pediatric renal disease

Congenital abnormalities of the kidney and urinary tract (CAKUT) account for more than half of all renal failure in children. For young adults with CAKUT two questions are paramount: what is the prognosis and what is the best management to improve outcome? The paediatric literature shows that prognostic factors are glomerular filtration rate (GFR) and the presence of proteinuria. We reviewed data from 101 young adult patients with either primary vesico-ureteric reflux and renal dysplasia or obstructive uropathy. Patients had an estimated GFR (eGFR) of <or=60 ml/min per 1.73 m(2) body surface area and had had at least 5 years of follow up (median 162 months). There was a strong correlation between the amount of proteinuria at the start and overall rate of decline. Angiotensin-converting enzyme inhibitors (ACEIs) slowed declining renal function at all levels of function, but this only had a significant effect on renal outcome when eGFR was >35 ml/min. The ACEI benefit increased with time. Rate of decline was slower than reported for other diseases and was only -2.4 ml/min per year for those reaching the start of dialysis. Outcome is predictable by the level of residual renal function (GFR). Nevertheless, function remains stable while proteinuria is minimal. Short-term studies overestimate rates of deterioration.

Dual blockade of the renin-angiotensin-aldosterone system: beyond the ACE inhibitor and angiotensin-II receptor blocker combination

The renin-angiotensin-aldosterone system (RAAS), an important regulator of blood pressure as well as fluid and electrolyte balance, plays an important role in the pathophysiology of cardiovascular and kidney diseases. Blockade of the RAAS with angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-II (ANG-II) receptor blockers (ARBs) lowers blood pressure, decreases morbidity and mortality in patients with chronic heart failure, and decreases proteinuria and the rate of decline in renal function in patients with chronic kidney disease. Although these drugs are highly effective and are widely used in the management of cardiovascular and kidney diseases, current treatment regimens with ACEIs and ARBs may not completely suppress the RAAS. Combinations of ACEIs and ARBs have been shown to be superior to either agent alone for some, but certainly not all, composite cardiovascular and kidney outcomes. With the growing appreciation of the role of aldosterone in the pathogenesis of cardiorenal diseases and the recent approval of the direct renin inhibitor (DRI), aliskiren, additional combination strategies have emerged that may offer novel ways to more fully suppress the RAAS. This review examines what is presently known about ACEI/ARB combination therapy and explores alternative combination strategies that include DRIs and mineralocorticoid receptor blockers (MRBs).

Mechanisms of the cardiorenal syndromes

The kidney and heart have essential roles in maintaining blood volume homeostasis and in the regulation of systemic blood pressure. Acute or chronic dysfunction in either the heart or kidneys can induce dysfunction in the other organ, resulting in the so-called cardiorenal syndromes, which are classified into five different types. Abrupt worsening of cardiac function predisposes an individual to acute kidney injury from renal hypoperfusion or renal congestion. Progressive, sometimes permanent, chronic kidney impairment can result from chronic renal hypoperfusion or congestion. Heart failure is common in patients with acute kidney injury. Chronic kidney disease predisposes individuals to atherosclerotic, arteriosclerotic and cardiomyopathic disease. Finally, both cardiac and renal disease can also occur secondary to systemic conditions, such as diabetes or autoimmune disease. This Review examines the mechanisms presiding over the first four types of cardiorenal syndromes. These mechanisms provide a template that accounts for the heart-kidney interactions that occur in patients whose concomitant cardiac and renal conditions result from a third cause.

Hypertriglyceridemia: an independent risk factor of chronic kidney disease in Taiwanese adults

BACKGROUND

The prevalence and incidence of chronic kidney disease (CKD) are relatively high in Taiwanese patients than in patients of other countries, particularly in the older age groups. Dyslipidemia in patients with CKD has been recognized as a risk factor for disease progression but the role of triglycerides (TGs) remains controversial. With this regard, we evaluated the effects of hypertriglyceridemia on renal function in Taiwanese adults (aged >or=40 years).

METHODS

From January 2002 to December 2006, we conducted a community-based medical screening program in Chiayi County with 18,422 subjects (aged >or=40 years). The CKD was defined as an estimated glomerular filtration rate of <60 mL min 1.73 m. Age, body mass index, systolic blood pressure, fasting plasma glucose, and serum total cholesterol were considered as potential confounders.

RESULT

The CKD was prevalent in 24.2% of the middle-aged and elderly population. By using multiple logistic regression models, we determined that old age and elevated levels of body mass index, systolic blood pressure, fasting plasma glucose, and cholesterol were associated with CKD. The adjusted odds ratios of CKD in participants with serum TG >==200 mg/dL was 1.901 (95% confidence interval: 1.07-3.36; P < 0.05) and in participants with serum TG > 500 mg/dL it increased to 2.205 (1.33-3.64, P < 0.05).

CONCLUSION

Hypertriglyceridemia is an independent risk factor for CKD in Taiwanese adults. Thus, an effective screening program that identifies people with hypertriglyceridemia is warranted.

Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers in Peritoneal Dialysis: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are widely used in clinical practice. The safety and efficacy of these agents in peritoneal dialysis (PD) patients are unclear.

Objectives

We conducted a systematic review to study the safety and efficacy of ACEI and ARB use in PD patients. Primary outcome measures were mortality and cardiovascular (CV) events; secondary outcome measures were renal function, proteinuria, hyperkalemia, and erythropoietin requirement at 3 months.

Methods

We searched Medline, EMBASE, Cochrane Central Register of Controlled Trials, trial registry Web sites, reference lists of eligible and review articles, as well as abstracts from the American Society of Nephrology and Canadian Society of Nephrology meetings. To be eligible, studies had to be randomized controlled trials that allocated PD patients to ACEI and ARB use or to placebo or other antihypertensive medications, included adult patients, and reported on at least one of the outcome measures.

Results

418 citations were identified. Four met the eligibility criteria. Three examined CV events and mortality, of which two studies did not have any events. The third showed no statistically significant difference between control and treatment groups in either CV events or mortality: odds ratio 1.56 [95% confidence interval (CI) 0.24 – 10.05] for mortality and odds ratio 1.00 (95% CI 0.19 – 5.40) for CV events. Two studies reported renal function at 12 months and the weighted mean difference was 0.91 mL/minute/1.73 m2 (95% CI 0.14 – 1.68), favoring ACEI and ARB use.

Conclusions

In PD patients, evidence for the use of ACEIs and ARBs for reduction of mortality and CV events is lacking. Limited data suggest that they slow the loss of residual renal function.

Renal volume, renin-angiotensin-aldosterone system, hypertension, and left ventricular hypertrophy in patients with autosomal dominant polycystic kidney disease

The relationship between renal volume and hypertension in autosomal dominant polycystic kidney disease (ADPKD) occurs in childhood. Hypertension is associated not only with increased kidney volume but also with significantly increased left ventricular mass index. Moreover, this increase in left ventricular mass index occurs in children who have ADPKD with borderline hypertension (75th to 95th percentile) and is prevented with angiotensin-converting enzyme inhibitor (ACEI) monotherapy. Progression from borderline to overt hypertension (> or =95th percentile) occurs during a 5-yr follow-up in approximately 50% of children with ADPKD and borderline hypertension. Renal cyst enlargement in ADPKD in adults is associated with stimulation of both the circulating and intrarenal renin-angiotensin-aldosterone system. In addition to hypertension, the resultant angiotensin in ADPKD is a pivotal factor in cyst proliferation and expansion, increased sympathetic and endothelin activity, oxidant injury, and fibrosis. There is a close correlation between the level of hypertension, left ventricular hypertrophy, deterioration of GFR, and the progressive enlargement of the cystic kidneys in adult ADPKD. Randomized clinical investigation indicates that ACEI and a BP goal of 120/80 mmHg are associated in a 7-yr study to reverse left ventricular hypertrophy. The effect of renin-angiotensin-aldosterone system inhibition with dual blockade, ACEI and angiotensin receptor antagonists, on renal volume and kidney function is under study in the Halt Progression of Polycystic Kidney Disease (HALT PKD) trial.

Effects ofFicus thonningii(Blume) [Morarceae] Stem-Bark Ethanolic Extract on Blood Glucose, Cardiovascular and Kidney Functions of Rats, and on Kidney Cell Lines of the Proximal (LLC-PK1) and Distal Tubules (MDBK)

Previous observations indicate that Ficus thonningii (Blume) [Moraceae] stem-bark extracts may be useful in the control of diabetes mellitus. Accordingly, we investigated in some experimental animal paradigms the effects of F. thonningii stem-bark ethanolic extract (FTE) on renal and cardiovascular functions as complications of diabetes. Oral glucose tolerance tests were conducted in separate groups of non-diabetic and STZ-treated diabetic rats given glucose load (0.86 g x kg(-1), p.o.) after 18-h fast, followed by various FTE doses (60, 120, and 240 mg x kg(-1)). Rats treated with deionized water (3 mL x kg(-1) p.o.), or metformin (500 mg x kg(-1) p.o.) acted as untreated and treated positive controls, respectively. Blood glucose was monitored at 15-min intervals for the first hour, and hourly thereafter for 3 h. Acute effects of FTE on kidney function and mean arterial blood pressure (MAP) were investigated in anaesthetized rats challenged with hypotonic saline after a 3.5-h equilibration for 4 h of 1 h control, 1.5 h treatment, and 1.5 h recovery periods. FTE was added to the infusate during the treatment period. Chronic effects of FTE were studied in individually caged rats treated daily with FTE (120 mg x kg(-1), p.o.) for five weeks. Cytotoxicity of FTE was assessed by dye-reduction colorimetric (MTT) assay on MDBK and LLCPK1 kidney cell lines exposed for 24 h, 48 h, and 72 h to graded concentrations of the extract. Myocardial contractile performance was evaluated on rat isolated atrial muscle strips. FTE, like metformin, decreased blood glucose levels in non-diabetic and STZ-diabetic rats. Both acute and chronic FTE treatments did not affect renal function. In vitro studies demonstrated that FTE increased MDBK cell metabolic activity by an average of 15% (72 h), and LLCPK1 mirrored the controls. Acute intravenous infusion of FTE reduced the MAP from 119 +/- 1 mmHg to 98 +/- 4 mmHg. The MAP also was reduced throughout the five-week experimental study period. FTE also produced concentration-dependent, negative inotropic and chronotropic effects on rat isolated, electrically driven left-, and spontaneously beating right-, atrial muscle preparations. Our experimental findings suggest that FTE possesses reno- and cardio-protective effects in diabetes mellitus.

Combination Therapy Improves Survival After Acute Myocardial Infarction in the Elderly with Chronic Kidney Disease

BACKGROUND

Individuals with chronic kidney disease have a high mortality rate after acute myocardial infarction. It is not known how frequently these individuals are prescribed combination cardioprotective therapy and if survival is affected by such therapy after acute myocardial infarction.

METHODS

A retrospective cohort study of 1,342 Medicare recipients with acute myocardial infarction. Data were collected by medical chart abstraction as part of the Cooperative Cardiovascular Project in 60 hospitals in North Carolina during 5/30/1996-12/28/1997. We categorized cardioprotective medication use as aspirin alone, aspirin with beta-blockers, and aspirin with beta-blockers and ace-inhibitors. Chronic kidney disease was defined as a derived glomerular filtration rate (GFR) ranging from 15-89 mL/min/1.73 m2. Cox proportional hazards regression analyses were performed to determine the effect of cardioprotective medication use on survival while controlling for potential explanatory variables.

RESULTS

The prevalence of cardioprotective medication use differed among levels of chronic kidney disease. Those with severe kidney disease (GFR 15-29 mL/min/1.73 m2) were less frequently prescribed aspirin with beta-blockers, 27.1%, and only 8.6% were prescribed aspirin with beta-blockers and ace-inhibitors. Survival was improved with prescribed cardioprotective medication use. In severe kidney disease (GFR 15-29 mL/min/1.73 m2), the hazards risk for death was 0.21 (0.08, 0.53) for aspirin alone, 0.17 (0.06, 0.51) for aspirin with beta-blockers, and 0.35 (0.09, 1.42) for aspirin with beta-blockers and ace-inhibitors.

CONCLUSIONS

Individuals with chronic kidney disease benefit from combination cardioprotective therapy, but are less likely to be prescribed them after acute myocardial infarction. Further investigation is warranted to identify possible reasons for these observed treatment disparities.

Cardiovascular implications of proteinuria: an indicator of chronic kidney disease

Proteinuria, defined as urine protein excretion greater than 300 mg over 24 h, is a strong and independent predictor of increased risk for all-cause and cardiovascular mortality in patients with and without diabetes. Proteinuria is a sign of persistent dysfunction of the glomerular barrier and often precedes any detectable decline in renal filtration function. Measurement of proteinuria is important in stratifying the risk for cardiovascular disease and chronic kidney disease progression. A variety of basic pathophysiologic mechanisms that can partially explain simultaneous renal and cardiac disease will be discussed in this Review. In addition to being a prognostic marker, proteinuria is being considered as a therapeutic target in cardiovascular medicine. Therapeutic strategies for amelioration of proteinuria by achieving blood pressure targets, glycemic control in diabetes, treatment of hyperlipidemia, and reducing dietary salt and protein intake are also reviewed in this paper. Future clinical studies are needed to assess if proteinuria reduction should be a target of treatment to reduce the burden of end-stage renal disease, cardiovascular disease, and improve survival in this high-risk population.