The effects of dual blockade of the renin- angiotensin system on urinary protein and transforming growth factor-b excretion in 2 groups of patients with IgA and diabetic nephropathy

Angiotensin-converting-enzyme inhibitors and angiotensin receptor blockers for preventing the progression of diabetic kidney disease

BACKGROUND

Guidelines suggest that adults with diabetes and kidney disease receive treatment with angiotensin-converting-enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). This is an update of a Cochrane review published in 2006.

OBJECTIVES

We compared the efficacy and safety of ACEi and ARB therapy (either as monotherapy or in combination) on cardiovascular and kidney outcomes in adults with diabetes and kidney disease.

SEARCH METHODS

We searched the Cochrane Kidney and Transplants Register of Studies to 17 March 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included studies evaluating ACEi or ARB alone or in combination, compared to each other, placebo or no treatment in people with diabetes and kidney disease.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias and extracted data. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

One hundred and nine studies (28,341 randomised participants) were eligible for inclusion. Overall, the risk of bias was high. Compared to placebo or no treatment, ACEi may make little or no difference to all-cause death (24 studies, 7413 participants: RR 0.91, 95% CI 0.73 to 1.15; I2 = 23%; low certainty) and with similar withdrawals from treatment (7 studies, 5306 participants: RR 1.03, 95% CI 0.90 to 1.19; I2 = 0%; low certainty). ACEi may prevent kidney failure (8 studies, 6643 participants: RR 0.61, 95% CI 0.39 to 0.94; I2 = 0%; low certainty). Compared to placebo or no treatment, ARB may make little or no difference to all-cause death (11 studies, 4260 participants: RR 0.99, 95% CI 0.85 to 1.16; I2 = 0%; low certainty). ARB have uncertain effects on withdrawal from treatment (3 studies, 721 participants: RR 0.85, 95% CI 0.58 to 1.26; I2 = 2%; low certainty) and cardiovascular death (6 studies, 878 participants: RR 3.36, 95% CI 0.93 to 12.07; low certainty). ARB may prevent kidney failure (3 studies, 3227 participants: RR 0.82, 95% CI 0.72 to 0.94; I2 = 0%; low certainty), doubling of serum creatinine (SCr) (4 studies, 3280 participants: RR 0.84, 95% CI 0.72 to 0.97; I2 = 32%; low certainty), and the progression from microalbuminuria to macroalbuminuria (5 studies, 815 participants: RR 0.44, 95% CI 0.23 to 0.85; I2 = 74%; low certainty). Compared to ACEi, ARB had uncertain effects on all-cause death (15 studies, 1739 participants: RR 1.13, 95% CI 0.68 to 1.88; I2 = 0%; low certainty), withdrawal from treatment (6 studies, 612 participants: RR 0.91, 95% CI 0.65 to 1.28; I2 = 0%; low certainty), cardiovascular death (13 studies, 1606 participants: RR 1.15, 95% CI 0.45 to 2.98; I2 = 0%; low certainty), kidney failure (3 studies, 837 participants: RR 0.56, 95% CI 0.29 to 1.07; I2 = 0%; low certainty), and doubling of SCr (2 studies, 767 participants: RR 0.88, 95% CI 0.52 to 1.48; I2 = 0%; low certainty). Compared to ACEi plus ARB, ACEi alone has uncertain effects on all-cause death (6 studies, 1166 participants: RR 1.08, 95% CI 0.49 to 2.40; I2 = 20%; low certainty), withdrawal from treatment (2 studies, 172 participants: RR 0.78, 95% CI 0.33 to 1.86; I2 = 0%; low certainty), cardiovascular death (4 studies, 994 participants: RR 3.02, 95% CI 0.61 to 14.85; low certainty), kidney failure (3 studies, 880 participants: RR 1.36, 95% CI 0.79 to 2.32; I2 = 0%; low certainty), and doubling of SCr (2 studies, 813 participants: RR 1.14, 95% CI 0.70 to 1.85; I2 = 0%; low certainty). Compared to ACEi plus ARB, ARB alone has uncertain effects on all-cause death (7 studies, 2607 participants: RR 1.02, 95% CI 0.76 to 1.37; I2 = 0%; low certainty), withdrawn from treatment (3 studies, 1615 participants: RR 0.81, 95% CI 0.53 to 1.24; I2 = 0%; low certainty), cardiovascular death (4 studies, 992 participants: RR 3.03, 95% CI 0.62 to 14.93; low certainty), kidney failure (4 studies, 2321 participants: RR 1.15, 95% CI 0.67 to 1.95; I2 = 29%; low certainty), and doubling of SCr (3 studies, 2252 participants: RR 1.18, 95% CI 0.85 to 1.64; I2 = 0%; low certainty). Comparative effects of different ACEi or ARB and low-dose versus high-dose ARB were rarely evaluated. No study compared different doses of ACEi. Adverse events of ACEi and ARB were rarely reported.

AUTHORS' CONCLUSIONS

ACEi or ARB may make little or no difference to all-cause and cardiovascular death compared to placebo or no treatment in people with diabetes and kidney disease but may prevent kidney failure. ARB may prevent the doubling of SCr and the progression from microalbuminuria to macroalbuminuria compared with a placebo or no treatment. Despite the international guidelines suggesting not combining ACEi and ARB treatment, the effects of ACEi or ARB monotherapy compared to dual therapy have not been adequately assessed. The limited data availability and the low quality of the included studies prevented the assessment of the benefits and harms of ACEi or ARB in people with diabetes and kidney disease. Low and very low certainty evidence indicates that it is possible that further studies might provide different results.

Non-immunosuppressive treatment for IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is the most common primary glomerular disease, with approximately 20% to 40% of patients progressing to kidney failure within 25 years. Non-immunosuppressive treatment has become a mainstay in the management of IgAN by improving blood pressure (BP) management, decreasing proteinuria, and avoiding the risks of long-term immunosuppressive management. Due to the slowly progressive nature of the disease, clinical trials are often underpowered, and conflicting information about management with non-immunosuppressive treatment is common. This is an update of a Cochrane review, first published in 2011.

OBJECTIVES

To assess the benefits and harms of non-immunosuppressive treatment for treating IgAN in adults and children. We aimed to examine all non-immunosuppressive therapies (e.g. anticoagulants, antihypertensives, dietary restriction and supplementation, tonsillectomy, and herbal medicines) in the management of IgAN.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to December 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of non-immunosuppressive agents in adults and children with biopsy-proven IgAN were included.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed search results, extracted data and assessed study quality. Results were expressed as mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI) using random-effects meta-analysis. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

This review includes 80 studies (4856 participants), of which 24 new studies (2018 participants) were included in this review update. The risk of bias within the included studies was mostly high or unclear for many of the assessed methodological domains, with poor reporting of important key clinical trial methods in most studies. Antihypertensive therapies were the most examined non-immunosuppressive therapy (37 studies, 1799 participants). Compared to placebo or no treatment, renin-angiotensin system (RAS) inhibition probably decreases proteinuria (3 studies, 199 participants: MD - 0.71 g/24 h, 95% CI -1.04 to -0.39; moderate certainty evidence) but may result in little or no difference to kidney failure or doubling of serum creatinine (SCr), or complete remission of proteinuria (low certainty evidence). Death, remission of haematuria, relapse of proteinuria or > 50% increase in SCr were not reported. Compared to symptomatic treatment, RAS inhibition (3 studies, 168 participants) probably decreases proteinuria (MD -1.16 g/24 h, 95% CI -1.52 to -0.81) and SCr (MD -9.37 µmol/L, 95% CI -71.95 to -6.80) and probably increases creatinine clearance (2 studies, 127 participants: MD 23.26 mL/min, 95% CI 10.40 to 36.12) (all moderate certainty evidence); however, the risk of kidney failure is uncertain (1 study, 34 participants: RR 0.20, 95% CI 0.01 to 3.88; very low certainty evidence). Death, remission of proteinuria or haematuria, or relapse of proteinuria were not reported. The risk of adverse events may be no different with RAS inhibition compared to either placebo or symptomatic treatment (low certainty evidence). In low certainty evidence, tonsillectomy in people with IgAN in addition to standard care may increase remission of proteinuria compared to standard care alone (2 studies, 143 participants: RR 1.90, 95% CI 1.45 to 2.47) and remission of microscopic haematuria (2 studies, 143 participants: RR 1.93, 95% CI 1.47 to 2.53) and may decrease relapse of proteinuria (1 study, 73 participants: RR 0.70, 95% CI 0.57 to 0.85) and relapse of haematuria (1 study, 72 participants: RR 0.70, 95% CI 0.51 to 0.98). Death, kidney failure and a > 50% increase in SCr were not reported. These trials have only been conducted in Japanese people with IgAN, and the findings' generalisability is unclear. Anticoagulant therapy, fish oil, and traditional Chinese medicines exhibited small benefits to kidney function in patients with IgAN when compared to placebo or no treatment. However, compared to standard care, the kidney function benefits are no longer evident. Antimalarial therapy compared to placebo in one study reported an increase in a > 50% reduction of proteinuria (53 participants: RR 3.13 g/24 h, 95% CI 1.17 to 8.36; low certainty evidence). Although, there was uncertainty regarding adverse events from this study due to very few events.

AUTHORS' CONCLUSIONS

Available RCTs focused on a diverse range of interventions. They were few, small, and of insufficient duration to determine potential long-term benefits on important kidney and cardiovascular outcomes and harms of treatment. Antihypertensive agents appear to be the most beneficial non-immunosuppressive intervention for IgAN. The antihypertensives examined were predominantly angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. The benefits of RAS inhibition appear to outweigh the harms in patients with IgAN. The certainty of the evidence of RCTs demonstrating a benefit of tonsillectomy to patients with Japanese patients with IgAN was low. In addition, these findings are inconsistent across observational studies in people with IgAN of other ethnicities; hence, tonsillectomy is not widely recommended, given the potential harm of therapy. The RCT evidence is insufficiently robust to demonstrate efficacy for the other non-immunosuppressive treatments evaluated here.

Combination Therapy Use and Associated Events in Clinical Practice Following Dissemination of Trial Findings: A De-Implementation Study Using Interrupted Time Series Analysis

PURPOSE

It takes 17 years, on average, for trial results to be implemented into practice. Using data from the Department of Veterans Affairs (VA), this study assessed the potential impact on clinical practice of the dissemination of findings from a randomized, controlled trial reporting harm with the use of combination therapy. Communication between research and VA Pharmacy Benefits Management Services (PBM)  provided the impetus for communication from the PBM about the findings of the trial in accordance with policy.

METHODS

In this de-implementation study, interrupted time series analysis was used for assessing prescribing patterns and adverse clinical events before and after the dissemination of the trial findings. The de-implementation strategy was multicomponent and multilevel. Strategies were aligned with categories outlined in the Expert Recommendations for Implementing Change: train and educate stakeholders, use evaluative and iterative strategies, develop stakeholder inter-relationships, change infrastructure, provide interactive assistance, and engage consumers. VA patients with type 2 diabetes mellitus, chronic kidney disease stages 1 to 3, and a moderate or severe albuminuria who received care between July 2008 and November 2017 were included. Patients were subgrouped according to treatment with an angiotensin-converting enzyme inhibitor + angiotensin receptor blocker. The primary end point was the prevalence of combination therapy use. Secondary end points were the incidences of acute kidney injury and hyperkalemia.

FINDINGS

This study followed 712,245 patients, 9297 of whom used combination therapy. Data were available from 428,535 and 283,710 patients pre- and post-intervention, respectively; among these, 8324 and 973 patients used combination therapy, the median ages were 66 and 68 years, and 96.92% and 98.82% were men. One month following communication from the PBM, the reductions in combination therapy users, acute kidney injury events, and hyperkalemia were 331.94 (95% CI, 500.27-163.32), 36.58% (95% CI, 31.90%-41.95%), and 25.49% (95% CI, 14.17%-36.07%) per 100,000 patients per month, respectively (all, P < 0.001), whereas before the communication, these changes were +14.84 (95% CI, 10.27-19.42), -3.46% (95% CI, 3.18-3.74), and -3.27% (95% CI, 2.66%-3.87%) (all, P < 0.001).

IMPLICATIONS

The apparent speed and impact of the implementation of changes resulting from the dissemination of trial findings into VA clinical practice are encouraging. The speed of implementation was much faster than average for health care providers in the United States. Established communications between research and clinical practice, as well as established policy and communications between PBM and clinical practice, may be a model for other health care organizations.

Efficacy and safety of dual vs single renin-angiotensin-aldosterone system blockade in chronic kidney disease: An updated meta-analysis of randomized controlled trials

BACKGROUND

To lower albuminuria and to achieve blood pressure (BP) goals, dual renin-angiotensin-aldosterone system (RAAS) inhibitors are sometimes used in clinical practice for the treatment of CKD. However, the efficacy and safety of dual RAAS blockade therapy remains controversial.

METHODS

PubMed, EMBASE, and Cochrane Library were searched, and random effects model was used to calculate the effect sizes of eligible studies. Potential sources of heterogeneity were detected by meta-regression and subgroup analysis.

RESULTS

The present meta-analysis of 72 randomized controlled trials with 10,296 patients demonstrated that dual RAAS blockade therapy was superior to monotherapy in reducing the urine albumin excretion, urine protein excretion, and BP. These beneficial effects were related to the decrease of glomerular filtration rate, the increase of serum potassium level, and higher rates of hyperkalemia and hypotension. Meanwhile, these effects did not lead to improvements in short-term or long-term outcomes, including doubling of serum creatinine, acute kidney injury, end-stage renal disease, mortality, and hospitalization. Compared with the single therapy, angiotensin-converting enzyme inhibitor (ACEI) in combination with angiotensin-receptor blocker (ARB) was a better dual therapy than ACEI or ARB in combination with renin inhibitor or aldosterone receptor antagonist in decreasing urine albumin excretion, urine protein excretion and BP, and the combination was not associated with a lower glomerular filtration rate.

CONCLUSION

Compared with the single therapy, ACEI in combination with ARB was a better dual therapy than ACEI or ARB in combination with renin inhibitor or aldosterone receptor antagonist. Although ACEI in combination with ARB was associated with higher incidences of hyperkalemia and hypotension, careful individualized management and potassium binders may further expand its application (PROSPERO number CRD42020179398).

Comparative efficacy of different renin angiotensin system blockade therapies in patients with IgA nephropathy: a Bayesian network meta-analysis of 17 RCTs

Background

IgA nephropathy (IgAN) is still one of the most prevalent forms of primary glomerulonephritis globally. However, no guidelines have clearly indicated which kinds of renin angiotensin system blockade therapies (ACEIs or ARBs or their combination) in patients with IgAN result in a greater reduction in proteinuria and a better preservation of kidney function. Thus, we conducted a Bayesian network analysis to evaluate the relative effects of these three therapy regimens in patients with IgAN.

Methods

The protocol was registered in PROSPERO with ID CRD42017073726. We comprehensively searched the PubMed, the Cochrane Library, Embase, China Biology Medicine disc, WanFang and CNKI databases for studies published since 1993 as well as some grey literature according to PICOS strategies. Pairwise meta-analysis and Bayesian network analysis were conducted to evaluate the effect of different regimens.

Results

Seventeen randomized controlled trials (RCTs) involving 1,006 patients were analyzed. Co-administration of ACEIs and ARBs had the highest probability (92%) of being the most effective therapy for reducing proteinuria and blood pressure, but ACEIs would be the most appropriate choice for protecting kidney function in IgAN.

Conclusion

The combination of ACEIs and ARBs seems to have a significantly better antiproteinuric effect and a greater reduction of blood pressure than ACEI or ARB monotherapy in IgAN. ACEIs appear to be a more renoprotective therapy regimen among three therapies.

Efficacy and Safety of Angiotensin-Converting Enzyme Inhibitor in Combination with Angiotensin-Receptor Blocker in Chronic Kidney Disease Based on Dose: A Systematic Review and Meta-Analysis

Background: The purpose of this meta-analysis was to evaluate the controversy of angiotensin-converting enzyme inhibitor (ACEI) in combination with angiotensin-receptor blocker (ARB) in the treatment of chronic kidney disease (CKD) based on dose.

Methods: PubMed, EMBASE, and Cochrane Library were searched to identify randomized controlled trials (RCTs) from inception to March 2020. The random effects model was used to calculate the effect sizes. Potential sources of heterogeneity were detected using sensitivity analysis and meta-regression.

Results: This meta-analysis of 53 RCTs with 6,375 patients demonstrated that in patients with CKD, ACEI in combination with ARB was superior to low-dose ACEI or ARB in reducing urine albumin excretion (SMD, −0.43; 95% CI, −0.67 to −0.19; p = 0.001), urine protein excretion (SMD, −0.22; 95% CI, −0.33 to −0.11; p < 0.001), and blood pressure (BP), including systolic BP (WMD, −2.89; 95% CI, −3.88 to −1.89; p < 0.001) and diastolic BP (WMD, −3.02; 95% CI, −4.46 to −1.58; p < 0.001). However, it was associated with decreased glomerular filtration rate (GFR) (SMD, −0.13; 95% CI, −0.24 to −0.02; p = 0.02) and increased rates of hyperkalemia (RR, 2.07; 95% CI, 1.55 to 2.76; p < 0.001) and hypotension (RR, 2.19; 95% CI, 1.35 to 3.54; p = 0.001). ACEI in combination with ARB was more effective than high-dose ACEI or ARB in reducing urine albumin excretion (SMD, −0.84; 95% CI, −1.26 to −0.43; p < 0.001) and urine protein excretion (SMD, −0.24; 95% CI, −0.39 to −0.09; p = 0.002), without decrease in GFR (SMD, 0.02; 95% CI, −0.12 to 0.15; p = 0.78) and increase in rate of hyperkalemia (RR, 0.94; 95% CI, 0.65 to 1.37; p = 0.76). Nonetheless, the combination did not decrease the BP and increased the rate of hypotension (RR, 3.95; 95% CI, 1.13 to 13.84; p = 0.03) compared with high-dose ACEI or ARB.

Conclusion: ACEI in combination with ARB is superior in reducing urine albumin excretion and urine protein excretion. The combination is more effective than high-dose ACEI or ARB without decreasing GFR and increasing the incidence of hyperkalemia. Despite the risk of hypotension, ACEI in combination with ARB is a better choice for CKD patients who need to increase the dose of ACEI or ARB (PROSPERO CRD42020179398).

Comparative proteinuria management of different angiotensin-converting enzyme inhibitors or angiotensin receptor blockers for normotensive patients with CKD: a Bayesian network meta-analysis

Background

Both angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are blood pressure-lowering agents, but they are also being used to control proteinuria in early chronic kidney disease (CKD) patients. However, clinically, some patients present merely proteinuria without hypertension. No guidelines pointed out how to select treatments for proteinuria in normotensive patients. Thus, we conducted a Bayesian network analysis to evaluate the relative effects of different kinds of ACEI or ARB or their combination on proteinuria and blood pressure reduction.

Methods

The protocol was registered in PROSPERO with ID CRD42017073721. A comprehensive literature database query was carried out systematically according to PICOS strategies. The primary outcome was reduction in proteinuria, and the secondary outcomes were eGFR reduction and blood pressure reduction. Random-effects pairwise and Bayesian network meta-analyses were used to estimate the effect of different regimens.

Results

A total of 14 RCTs with 1,098 patients were included in the analysis. All treatment strategies of ACEI, ARB or their combination had significantly greater efficacy in reducing proteinuria than placebo in normotensive CKD patients. The combination therapy of olmesartan+temocapril had the highest probability (22%) of being the most effective treatment to reduce proteinuria in normotensive CKD patients. Olmesartan and lisinopril ranked second (12%), and temocapril ranked third (15%) but reduced blood pressure less than placebo. For IgA nephropathy, the combination therapy of olmesartan+temocapril also had the highest probability (43%) of being the best antiproteinuric treatment, while enalapril had the highest probability (58%) of being the best antiproteinuric therapy for diabetic nephropathy.

Conclusions

The combination therapy of olmesartan plus temocapril appeared to be the most efficacious for reducing proteinuria in normotensive CKD patients and IgA nephropathy, but the clinical application should be balanced against potential harms. Temocapril can be an option when practitioners are searching for more proteinuria reduction but less blood pressure variation. In normotensive diabetic nephropathy, monotherapy with the ACEI enalapril seems to be the most efficacious intervention for reducing albuminuria. Future studies are required to give a more definitive recommendation.

TGFB1-Mediated Gliosis in Multiple Sclerosis Spinal Cords Is Favored by the Regionalized Expression of HOXA5 and the Age-Dependent Decline in Androgen Receptor Ligands

In multiple sclerosis (MS) patients with a progressive form of the disease, spinal cord (SC) functions slowly deteriorate beyond age 40. We previously showed that in the SC of these patients, large areas of incomplete demyelination extend distance away from plaque borders and are characterized by a unique progliotic TGFB1 (Transforming Growth Factor Beta 1) genomic signature. Here, we attempted to determine whether region- and age-specific physiological parameters could promote the progression of SC periplaques in MS patients beyond age 40. An analysis of transcriptomics databases showed that, under physiological conditions, a set of 10 homeobox (HOX) genes are highly significantly overexpressed in the human SC as compared to distinct brain regions. Among these HOX genes, a survey of the human proteome showed that only HOXA5 encodes a protein which interacts with a member of the TGF-beta signaling pathway, namely SMAD1 (SMAD family member 1). Moreover, HOXA5 was previously found to promote the TGF-beta pathway. Interestingly, SMAD1 is also a protein partner of the androgen receptor (AR) and an unsupervised analysis of gene ontology terms indicates that the AR pathway antagonizes the TGF-beta/SMAD pathway. Retrieval of promoter analysis data further confirmed that AR negatively regulates the transcription of several members of the TGF-beta/SMAD pathway. On this basis, we propose that in progressive MS patients, the physiological SC overexpression of HOXA5 combined with the age-dependent decline in AR ligands may favor the slow progression of TGFB1-mediated gliosis. Potential therapeutic implications are discussed.

Angiotensin receptor blockers are associated with lower mortality than ACE inhibitors in predialytic stage 5 chronic kidney disease: A nationwide study of therapy with renin-angiotensin system blockade

Dual renin angiotensin system (RAS) blockade using angiotensin-receptor blockers (ARBs) in combination with angiotensin converting enzyme inhibitors (ACEIs) is reported to improve proteinuria in both diabetic and non-diabetic patients. However, its renoprotective effect and safety remain uncertain in patients with advanced chronic kidney disease (CKD). From January 1, 2000 through June 30, 2009, we enrolled 14,117 pre-dialytic stage 5 CKD patients with serum creatinine >6mg/dL and hematocrit <28% under the treatment with erythropoiesis stimulating agents and RAS blockade. We used Cox proportional hazards regression models to estimate the hazard ratios (HRs) against the commencement of long-term dialysis and all-cause mortality for ACEI/ARB users. Over a median follow-up of 7 months, 9,867 patients (69.9%) required long-term dialysis and 2,805 (19.9%) died before progression to end-stage renal disease requiring dialysis. In comparison with the ARB-only users, dual blockade with ACEIs and ARBs was associated with a significantly higher risk of (1) death in all CKD patients (HR = 1.49, [95%CI, 1.30-1.71]; P = 0.02) and in diabetic subgroup (HR = 1.58, [95%CI, 1.34-1.86]; P = 0.02); (2) composite endpoint of long-term dialysis or death in diabetic subgroup (HR = 1.10, [95%CI, 1.01-1.20]; P = 0.04); (3) hyperkalemia-associated hospitalization in non-diabetic subgroup (HR, 2.74, [95%CI, 1.05-7.15]; P = 0.04). However, ACEIs users were associated with higher mortality than ARBs users in all CKD patients (HR = 1.17, [95%CI, 1.07-1.27]; P = 0.03) and in diabetic subgroup (HR = 1.32, [95%CI, 1.18-1.48]; P = 0.03). Monotherapy of RAS blockade, especially ARB, is more effective and safer than dual RAS blockade in pre-dialytic stage 5 CKD patients.

Combined Treatment With Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Review of the Current Evidence

Several studies have shown that angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are useful in the treatment of hypertension, cardiovascular disease, chronic heart failure, and some types of nephropathy. In this context, dual renin-angiotensin system blockade with both angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may be more effective than treatment with each agent alone. Many clinical trials have demonstrated the beneficial effect of this combined treatment on proteinuria, hypertension, heart failure, and cardiovascular events. Moreover, these studies demonstrated that dual renin-angiotensin system blockade is generally safe and well tolerated. Long-term studies are under way to confirm these effects and also investigate the effectiveness of dual reninangiotensin system blockade on cerebrovascular disease and prevention of type 2 diabetes mellitus. These studies are expected to define the optimal use of combination treatment in everyday clinical practice. This review considers the most important clinical trials that evaluated the effect of dual renin-angiotensin system blockade on blood pressure, heart failure, and renal function.

The effect of aliskiren on urinary cytokine/chemokine responses to clamped hyperglycaemia in type 1 diabetes

AIMS/HYPOTHESIS

Acute clamped hyperglycaemia activates the renin-angiotensin-aldosterone system (RAAS) and increases the urinary excretion of inflammatory cytokines/chemokines in patients with uncomplicated type 1 diabetes mellitus. Our objective was to determine whether blockade of the RAAS would blunt the effect of acute hyperglycaemia on urinary cytokine/chemokine excretion, thereby giving insights into potentially protective effects of these agents prior to the onset of clinical nephropathy.

METHODS

Blood pressure, renal haemodynamic function (inulin and para-aminohippurate clearances) and urinary cytokines/chemokines were measured after 6 h of clamped euglycaemia (4-6 mmol/l) and hyperglycaemia (9-11 mmol/l) on two consecutive days in patients with type 1 diabetes mellitus (n = 27) without overt nephropathy. Measurements were repeated after treatment with aliskiren (300 mg daily) for 30 days.

RESULTS

Before aliskiren, clamped hyperglycaemia increased filtration fraction (from 0.188 ± 0.007 to 0.206 ± 0.007, p = 0.003) and urinary fibroblast growth factor-2 (FGF2), IFN-α2 and macrophage-derived chemokine (MDC) (p < 0.005). After aliskiren, the filtration fraction response to hyperglycaemia was abolished, resulting in a lower filtration fraction after aliskiren under clamped hyperglycaemic conditions (p = 0.004), and none of the biomarkers increased in response to hyperglycaemia. Aliskiren therapy also reduced levels of urinary eotaxin, FGF2, IFN-α2, IL-2 and MDC during clamped hyperglycaemia (p < 0.005).

CONCLUSIONS/INTERPRETATION

The increased urinary excretion of inflammatory cytokines/chemokines in response to acute hyperglycaemia is blunted by RAAS blockade in humans with uncomplicated type 1 diabetes mellitus.

Efficacy and safety of combined vs. single renin-angiotensin-aldosterone system blockade in chronic kidney disease: a meta-analysis

BACKGROUND

Although dual blockade of the renin-angiotensin-aldosterone system (RAAS) has gained popularity for the treatment of kidney disease, its benefits and potential risks have not been fully elucidated. We conducted a meta-analysis of all randomized controlled trials comparing the efficacy and safety of combined vs. single RAAS blockade therapy in chronic kidney disease (CKD).

METHODS

We performed a literature search using MEDLINE, the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, scientific abstracts from meetings, and bibliographies of retrieved articles. We used random-effects models to compute net changes and rate differences in variables.

RESULTS

Fifty-nine (25 crossover and 34 parallel-arm) randomized controlled trials (RCTs) comparing the efficacy and safety of combined vs. single RAAS blockade therapy in CKD were identified (4,975 patients). Combined RAAS blockade therapy was associated with a significant net decrease in glomerular filtration rate (GFR) (-1.8ml/min or ml/min/1.73 m(2); P = 0.005), albuminuria (-90mg/g of creatinine; P = 0.001 or -32mg/day; P = 0.03), and proteinuria (-291mg/g; P = 0.003 or -363mg/day; P < 0.001). Combined RAAS blockade therapy was associated with a 9.4% higher rate of regression to normoalbuminuria and a 5% higher rate of achieving the blood pressure (BP) goal (as defined in individual trials). However, combined RAAS blockade therapy was associated with a significant net increase in serum potassium level, a 3.4% higher rate of hyperkalemia, and a 4.6% higher rate of hypotension. There was no effect on doubling of the serum creatinine level, hospitalization, or mortality.

CONCLUSIONS

Although combined RAAS blockade therapy in CKD is associated with a decrease in albuminuria and proteinuria, it is associated with a decrease in GFR and a higher incidence of hyperkalemia and hypotension relative to monotherapy. The potential long-term kidney benefits of combined RAAS blockade therapy require further study.

Combination therapy an ACE inhibitor and an angiotensin receptor blocker for IgA nephropathy: a meta-analysis

OBJECTIVE

The pathogenesis of IgA nephropathy (IgAN) is still unknown. Combination therapy with angiotensin-converting enzyme inhibitors (ACEIs) plus angiotensin receptor blockers (ARBs) might provide more benefits to IgAN patients. We conducted a systematic review to assess the efficacy of combination therapy for IgAN.

METHODS

The MEDLINE, EMBASE, the Cochrane Library and article reference lists were searched for randomised clinical trials (RCTs) which involved combination therapy ACEI plus ARB in only one arm. A meta-analysis was performed on the outcomes of proteinuria and renal function in IgAN patients.

RESULTS

Six RCTs involving 109 patients were included in the review. Combined treatment with ACEI plus ARB was more effective than with ACEI/ARB alone for reducing daily proteinuria. This did not translate into an improvement in GFR. Patients receiving ACEI plus ARB therapy did not have an increased risk of hyperkalemia.

CONCLUSIONS

The current cumulative evidence suggests that combination therapy ACEI plus ARB may provide more benefits to IgAN patients for reducing daily proteinuria. Long-term effects of these agents on renal outcomes, and safety need to be established.

Non-immunosuppressive treatment for IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is the most common primary glomerular disease with approximately 30% to 40% of patients progressing to end-stage kidney disease (ESKD) within 20 years. The most common regimens include immunosuppressive agents, however the risks of long-term treatment often outweigh the potential benefits. Non-immunosuppressive options, including fish oils, anticoagulants, antihypertensive agents and tonsillectomy have also been examined but not reviewed systematically.

OBJECTIVES

To assess the benefits and harms of non-immunosuppressive treatments for treating IgAN in adults and children.

SEARCH STRATEGY

In July 2010 we searched the Cochrane Renal Group's specialised register, CENTRAL (in The Cochrane Library), MEDLINE (from 1966) and EMBASE (from 1980). We also searched reference lists of included studies, review articles and contacted local and international experts.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of non-immunosuppressive agents in adults and children with biopsy-proven IgAN were included.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed search results, extracted data and assessed study quality. Results were expressed as mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI) using a random-effects model.

MAIN RESULTS

We included 56 studies (2838 participants). Antihypertensive agents were the most beneficial non-immunosuppressive intervention for IgAN. The antihypertensives examined were predominantly angiotensin-converting enzyme inhibitors (ACEi), angiotensin receptor blockers (ARB) or combinations of both, versus other antihypertensives and other agents. The benefits of antihypertensive agents, particularly inhibitors of the renin angiotensin system, appear to potentially outweigh the harms in patients with IgAN. The benefits are largely manifest as a reduction in proteinuria, a surrogate outcome. There is no evidence that treatment with any of the antihypertensive agents evaluated affect major renal and/or cardiovascular endpoints or long-term mortality risk beyond the benefit that arises from controlling hypertension in patients with IgAN. The RCT evidence is insufficiently robust to demonstrate efficacy for any of the other non-immunosuppressive therapies evaluated here.

AUTHORS' CONCLUSIONS

IgAN remains a disease in search of adequately powered RCTs to reliably inform clinical practice. More and better evidence is needed to understand the magnitude of benefit and the possible risks of anti-hypertensive or more specifically of ACEi/ARB therapy alone or in combination and which specific types of patients with the IgAN might have the greatest potential for benefit. For other non-immunosuppressive therapies, where neither benefit nor significant harm has yet to be demonstrated, there remains some justification for further exploration of the potential benefits.

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.

ACE inhibitors, angiotensin receptor blockers and direct renin inhibitors in combination: a review of their role after the ONTARGET trial

BACKGROUND

Clinical trials have shown organ-protective effects of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs); however, cardiovascular mortality and morbidity rates, and decline in renal function remain high. In the ONTARGET trial in patients with hypertension at high cardiovascular risk, ACE inhibitor/ARB combination therapy provided no significant clinical outcome benefits over monotherapy, and was associated with a worse safety and tolerability profile. These results raise the question of whether ACE inhibitor/ARB, direct renin inhibitor (DRI)/ACE inhibitor and DRI/ARB combinations are of clinical value.

SCOPE

Using PubMed and EMBASE databases, we conducted a systematic review of clinical trials published before June 2008 evaluating dual intervention with ACE inhibitors and ARBs, and compared these with trials of DRI/ACE inhibitor or DRI/ARB combinations.

FINDINGS

A total of 70 studies met the inclusion criteria for this analysis. In patients with hypertension, ACE inhibitor/ARB combinations provided limited additional reductions in blood pressure (BP) over monotherapy. Outcomes benefits were unclear: VALIANT and ONTARGET demonstrated no enhanced outcome benefit of combination therapy over monotherapy; Val-HeFT and CHARM-Added showed reduced morbidity/mortality in patients with heart failure, but at the expense of poorer tolerability. Combination therapy with the DRI aliskiren and an ACE inhibitor or ARB provided significant additional BP reductions over monotherapy in patients with mild-to-moderate hypertension, and reduced surrogate markers of organ damage in patients with heart failure or diabetic nephropathy, with generally similar safety and tolerability to the component monotherapies. No morbidity and mortality data for DRI/ACE inhibitor or DRI/ARB combinations are currently available.

CONCLUSIONS

ACE inhibitor/ARB combinations showed equivocal effects on clinical outcomes. DRI/ACE inhibitor and DRI/ARB combinations reduced markers of organ damage, but longer-term trials are required to establish whether more complete renin--angiotensin--aldosterone system control with aliskiren-based therapy translates into improved outcome benefits.

Pulse pressure lowering effect of dual blockade with candesartan and lisinopril vs. high-dose ACE inhibition in hypertensive type 2 diabetic subjects: a CALM II study post-hoc analysis

BACKGROUND

Elevated pulse pressure (PP) is strongly associated with micro- and macrovascular complications in type 2 diabetic patients. We examined the effect of 12 months of dual blockade with candesartan and lisinopril vs. high-dose lisinopril monotherapy on ambulatory PP in hypertensive type 2 diabetic patients from the CALM (Candesartan and Lisinopril Microalbuminuria Trial) II study.

METHODS

The CALM II study was a 12-month prospective, randomized, parallel-group, double-masked study that included 75 type 1 and type 2 diabetic subjects with hypertension. Participants were randomized for treatment with either high-dose lisinopril (40 mg once daily (o.d.)) or for dual blockade treatment with candesartan (16 mg o.d.) and lisinopril (20 mg o.d.). In this article, we present data from the post-hoc subgroup of 51 type 2 diabetic subjects who completed the full 12-month study period with successful ambulatory blood pressure (BP) measurements at both baseline and follow-up visits.

RESULTS

Baseline 24-h BP values were similar in the two groups (24-h systolic BP (SBP) 130 +/- 12 vs. 127 +/- 9, 24-h diastolic BP (DBP) 77 +/- 8 vs. 74 +/- 7, and 24-h PP 53 +/- 8 vs. 53 +/- 7 mm Hg, for the lisinopril and dual blockade groups, respectively, P > 0.2 for all). Compared with lisinopril monotherapy, dual blockade treatment caused a highly significant reduction in 24-h PP levels (-5 +/- 5 mm Hg, P = 0.003), albeit the difference in the BP lowering effect between the treatment groups did not differ significantly for 24-h systolic (P = 0.21) or diastolic (P = 0.49) BP. Dual blockade treatment significantly lowered 24-h SBP (-5 +/- 11 mm Hg, P = 0.03), but not 24-h DBP (-2 +/- 7 mm Hg, P = 0.29), whereas in the lisinopril group, the opposite effect was observed (24-h SBP -1 +/- 9 mm Hg, P = 0.45, 24-h SBP -3 +/- 7 mm Hg, P = 0.03).

CONCLUSIONS

Twelve months of dual blockade with candesartan and lisinopril significantly reduced PP when compared with high-dose monotherapy with lisinopril. Larger studies are needed to confirm this observation, and to evaluate whether this effect translates into a greater degree of end-organ protection from dual blockade treatment than from conventional angiotensin-converting enzyme (ACE) inhibition.

Rationale for combination angiotensin receptor blocker and angiotensin-converting enzyme inhibitor treatment and end-organ protection in patients with chronic kidney disease

Chronic kidney disease (CKD) is a major public health problem that has received increasing attention because of the high rate of associated cardiovascular morbidity and mortality. Mounting evidence indicates that angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), drugs that inhibit the renin-angiotensin-aldosterone system (RAAS) safely slow down progression of CKD. There is also growing evidence supporting combination treatment of nephropathies with an ACE inhibitor plus an ARB to more completely block the RAAS and provide greater renoprotection than either an ACE inhibitor-based or ARB-based regimen. The National Kidney Foundation suggests that ACE inhibitors and ARBs may be used in combination to reduce proteinuria in patients with kidney disease; however, larger outcomes trials are needed.

IgA nephropathy: what's new?

Although IgA nephropathy has only been recognized as a definitive entity for fewer than 40 years, its place in the world as a prominent cause for progressive kidney disease is well established. The extent to which we understand the role of genetically derived abnormal forms of the IgA molecule in the disease is evolving, and this will, hopefully, translate into more specific modes of treatment for patients in the future. In the meantime, we have few specific therapeutic options, most of which have not been well studied in large numbers of patients. The extent to which we can define which patients are likely to progress--and hence should be considered candidates for treatment--will be discussed in this Commentary. In addition, the notion that some patients may have reached "the point of no return" will also be addressed. Unfortunately, most of the comments will be based on results obtained in studies conducted in adults--a situation that is very familiar to pediatric nephrologists.

Therapeutic potential of TGF-beta inhibition in chronic renal failure

Chronic kidney diseases are emerging as a worldwide public health problem. The progression of kidney diseases closely correlates with the accumulation of extracellular matrix leading to glomerulosclerosis and tubulointerstitial injury. Transforming growth factor (TGF)-beta has been identified as a key mediator of kidney matrix accumulation. Overexpression of TGF-beta isoforms and their receptors was observed in a variety of renal diseases in both animals and humans. Given its crucial role in fibrotic kidney disease, TGF-beta has been recently considered as a possible target in the management of chronic renal diseases. This review discusses the role of TGF-beta in renal fibrosis and provides an overview of the strategies that, when interfering with TGF-beta expression and signalling, could be employed as new renoprotective treatments.

Renal injury due to renin-angiotensin-aldosterone system activation of the transforming growth factor-beta pathway

Glomerulosclerosis, interstitial fibrosis, and tubular atrophy occur with end-stage kidney failure, irrespective of the primary etiology. The transforming growth factor-beta (TGF-beta) is a key factor in these alterations either directly, by stimulating synthesis of extracellular matrix components and reducing collagenase production, or indirectly through other profibrogenic factors such as connective tissue growth factor (CTGF). TGF-beta is important for the proliferation of intrarenal fibroblasts and the epithelial-mesenchymal transition through which tubular cells become fibroblasts. Although several factors induce TGF-beta expression in the kidney, one very interesting aspect is the link between the renin-angiotensin-aldosterone (Aldo) system (RAAS) and TGF-beta. Angiotensin II (ANG II) stimulates TGF-beta expression in the kidney by various mechanisms and upregulates receptors for TGF-beta. ANG II can directly phosphorylate Smads without inducing TGF-beta. Recent data provide compelling evidence that other components of the RAAS including ANG III, renin, and Aldo also activate the TGF-beta system. As direct modulation of the TGF-beta system is not yet feasible in humans, angiotensin-converting enzyme (ACE) inhibitors and angiotensin type 1 (AT1)-receptor blockers are currently the most potential drugs to interfere with this ANG II-mediated TGF-beta expression. This review highlights some current aspects of the interaction between the RAAS and the TGF-beta axis.

Beneficial Effect of TGFβ Antagonism in Treating Diabetic Nephropathy Depends on When Treatment Is Started

BACKGROUND

In diabetic rats with maximal activation of RAS induced by uninephrectomy, late treatment with anti-TGFbeta antibody limited renal injury only when combined with ACE inhibitor. We investigated whether in a two-kidney diabetic model the time at which treatment started predicted the response to TGFbeta antagonist.

METHODS

27 weeks after streptozotocin injection, animals had mild proteinuria and were randomized to receive irrelevant antibody, anti-TGFbeta antibody (1D11) or enalapril till 52 weeks (early treatment). The effect of agents alone or combined was also evaluated at the time of overt proteinuria (late treatment, 52-61 weeks).

RESULTS

When given early, 1D11 displayed marked antihypertensive and antiproteinuric effects. Glomerulosclerosis was reduced to the extent that a remarkable percentage of glomeruli without sclerosis appeared after treatment. Podocyte number was normalized. Renoprotection of 1D11 was comparable to enalapril. Despite control of blood pressure, in late treatment single agents did not reduce proteinuria significantly. Glomerulosclerosis and podocyte loss were partially limited by 1D11 or enalapril, but full protection was achieved by combination.

CONCLUSIONS

Renoprotective effect of TGFbeta antagonism crucially depends on the time at which treatment started. Effectiveness of early treatment with 1D11 would indicate that TGFbeta is a major mediator of damage in early diabetes. To tackle the renal damage in the phase of advanced disease, a combined treatment with ACE inhibitor is needed.

Dual blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in chronic kidney disease

Despite the renoprotective effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs), many patients with chronic kidney disease develop end-stage kidney disease. Combination treatment with an ACEI and an ARB is a recently introduced approach to obtain more complete blockade of the renin-angiotensin system, based on the different mechanisms of action of the two classes of drug. To assess the shortcomings of single treatment with ACEIs and ARBs, and the potential benefits of combination treatment, we reviewed the experimental and clinical evidence suggesting that combination treatment offers more complete blockade of the renin-angiotensin system and identified areas in which further research is necessary to confirm the benefits of combination treatment. The available data suggest that combination treatment with an ACEI and an ARB has a greater renoprotective effect than either drug alone. In addition, more recent data have shown that combination treatment is more potent in suppressing renal fibrosis, and is well tolerated in patients with advanced chronic kidney disease. Clinical trials with rigorous endpoints are needed to further establish the benefits of combination treatment in renal protection.

Combination Therapy With an Angiotensin Receptor Blocker and an ACE Inhibitor in Proteinuric Renal Disease: A Systematic Review of the Efficacy and Safety Data

Blockade of the renin-angiotensin system with either an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker (ARB) was shown to decrease urinary protein excretion and slow the progression of both diabetic and nondiabetic proteinuric renal disease. The safety and efficacy of combined ACE-inhibitor and ARB therapy is not well established. We conducted a systematic review and meta-analysis of randomized trials evaluating the combination of an ACE inhibitor and an ARB in patients with chronic proteinuric renal disease. Twenty-one randomized controlled studies (n = 654 patients) were identified using MEDLINE, EMBASE, and Cochrane Central databases. Five trials had a parallel-group design and 16 trials used a crossover design. Combination therapy with an ACE inhibitor and an ARB resulted in a small, but significant, increase in serum potassium levels (weighted mean difference, 0.11 mEq/L [0.11 mmol/L]; 95% confidence interval [CI], 0.05 to 0.17) and a nonsignificant decrease in glomerular filtration rate (weighted mean difference, 1.4 mL/min [0.02 mL/s]; 95% CI, -2.6 to 0.2). Addition of an ARB resulted in a further decrease in proteinuria (weighted mean difference, 440 mg/d; 95% CI, 289 to 591) compared with an ACE inhibitor alone. This effect was observed in patients with diabetic (210 mg/d; 95% CI, 84 to 336) and nondiabetic (582 mg/d; 95% CI, 371 to 793) renal disease. In conclusion, the combination of ACE-inhibitor and ARB therapy in patients with chronic proteinuric renal disease is safe, without clinically meaningful changes in serum potassium levels or glomerular filtration rates. Combination therapy also was associated with a significant decrease in proteinuria, at least in the short term. Additional trials with longer follow-up are needed to determine whether the decrease in proteinuria will result in significant preservation of renal function.

Hong Kong study using valsartan in IgA nephropathy (HKVIN): a double-blind, randomized, placebo-controlled study

BACKGROUND

Previous studies showed that angiotensin-receptor blocker (ARB) therapy decreased proteinuria and possibly slowed the rate of renal function decline in patients with chronic proteinuric nephropathies. We performed a double-blind, randomized, placebo-controlled, multicenter study on the ARB valsartan in the treatment of patients with immunoglobulin A (IgA) nephropathy.

METHODS

From 6 centers, we recruited 109 patients with IgA nephropathy who had either: (1) proteinuria with protein greater than 1 g/d and serum creatinine level less than 2.8 mg/dL (< 250 micromol/L), or (2) serum creatinine level of 1.4 to 2.8 mg/dL (120 to 250 micromol/L) regardless of degree of proteinuria. Patients were randomly assigned to administration of either valsartan, 80 mg/d (titrated up to 160 mg/d for blood pressure control), or placebo for 104 weeks. Additional antihypertensive therapy was allowed to achieve a target blood pressure of 140/90 mm Hg. The primary end point was doubling of serum creatinine level or dialysis-dependent renal failure. Secondary outcomes included change in proteinuria and decrease in glomerular filtration rate (GFR).

RESULTS

There were 54 patients in the treatment group and 55 patients in the placebo group. Baseline clinical characteristics were similar between groups, although the treatment group had a marginally greater baseline GFR (87 +/- 36 versus 78 +/- 38 mL/min/1.73 m2 [1.45 +/- 0.60 versus 1.30 +/- 0.63 mL/s/1.73 m2];P = 0.29) and less proteinuria (protein, 1.8 +/- 1.2 versus 2.3 +/- 1.7 g/d; P = 0.21) than the placebo group. Average blood pressures during the study were 92.7 +/- 10.6 mm Hg in the treatment group and 100.9 +/- 9.1 mm Hg in the placebo group (P < 0.001). During the study period, 4 patients in the placebo group and 1 patient in the treatment group reached the primary end point (log-rank test, P = 0.18). Proteinuria decreased significantly in the treatment group (protein, 1.8 +/- 1.2 to 1.2 +/- 1.2 g/d; P = 0.03), but did not change in the placebo group. With multiple linear regression models, valsartan treatment resulted in a 33.0% decrease in proteinuria (95% confidence interval, 10.9 to 55.1) after adjusting for other confounding factors. There was a significant decrease in mean rate of GFR decrease in the valsartan-treated group (-5.62 +/- 6.79 mL/min/y [-0.09 +/- 0.11 mL/s/y]) compared with the placebo group (-6.98 +/- 6.17 mL/min/y [-0.12 +/- 0.10 mL/s/y]) throughout the study period after adjustment for average blood pressure and proteinuria (P = 0.014).

CONCLUSION

Valsartan significantly decreases proteinuria and slows renal deterioration in patients with IgA nephropathy after adjustment for confounding factors, notably blood pressure. The long-term benefit of valsartan needs to be confirmed with additional studies.

Accurate measurement and clinical significance of urinary transforming growth factor-beta1

Transforming growth factorbeta1 (TGF-beta1) is the main modulator of the healing process after tissue injury. In the kidney, if TGF-beta1 release is not switched off, extracellular matrix components (ECM) are accumulated and tissue fibrosis occurs. Urinary TGF-beta1 levels reflect its renal production and it has been determined in various types of glomerular disease. In this review, a critical analysis of the different immunoassays that have been used for the measurement of TGF-beta1 in the urine is presented and the importance of the serial determination of urinary TGF-beta1 levels in patients with various types of renal disease is discussed.

Effect of low-dose dual blockade of renin-angiotensin system on urinary TGF-beta in type 2 diabetic patients with advanced kidney disease

BACKGROUND

We evaluated the renoprotective effects of dual blockade of renin-angiotensin system (RAS) by using a low-dose combination of ACE inhibiter and angiotensin II receptor blocker in type 2 diabetic patients with advanced kidney disease. The amount of proteinuria and the urinary levels of bioassayable TGF-beta1 were used as surrogate markers of renal injury and sclerosis.

METHODS

We performed a prospective double-blinded randomized crossover trial consisting of three 16-week treatment periods with ramipril alone (10 mg/day), candesartan alone (16 mg/day), and ramipril (5 mg/day) plus candesartan (8 mg/day) combination therapy. Twenty-one type 2 diabetic patients with overt nephropathy with a 24 h urinary protein excretion rate (UPER) of > 1.0 g/24 h and creatinine clearance (Ccr) of 30 to 59 ml/min/1.73 m2 completed the entire study.

RESULTS

Subjects consisted of 10 female and 11 male patients with a mean age of 49 +/- 8 years and duration of diabetes ranging from 4 to 13 years. At baseline, 24-h blood pressures (BPs) were 133 +/- 6/81 +/- 7 mmHg, Ccr 40.6 +/- 4.1 ml/min/1.73 m2, 24-h UPER 4.1 +/- 1.9 g/24 h, and urinary TGF-beta1 level 28.4 +/- 16.1 pg/mg creatinine (cr). Although there was no comparable change in BP and plasma/urinary biochemical parameters, 24-h UPER was significantly reduced by the combination therapy (2.9 +/- 1.4 g/24 h) compared with that of ramipril (3.5 +/- 1.8 g/24 h) and of candesartan (3.3 +/- 2.0 g/24 h) single therapy (P < 0.05). Urinary TGF-beta1 level was reduced in all three therapies compared with that of the control (28.4 +/- 16.1 pg/mg cr) (P < 0.05). However, the combination therapy showed the most significant change (combination 19.6 +/- 10.6 pg/mg cr; ramipril 24.7 +/- 13.3 pg/mg cr; candesartan; 23.4 +/- 11.7 pg/mg cr). No significant or irreversible adverse effect was observed in the 21 patients who completed the entire study.

CONCLUSIONS

The dual blockade of RAS with low-dose ramipril plus candesartan was found to be safe and offered additive benefits with respect to reducing proteinuria and urinary TGF-beta1 excretion in diabetic patients with advanced kidney disease. These benefits were evident as compared with single ramipril and candesartan therapies at doses two-fold greater. Further study on the dose-titration is mandatory in terms of safety and especially for maximizing renoprotection in this patient population.

Kidney Expression of RhoA, TGF-β1, and Fibronectin in Human IgA Nephropathy

BACKGROUND

The Rho/transforming growth factor-beta (TGF-beta) system plays a crucial role in the progression of renal damage due to stimulation of extracellular matrix molecule deposition. In fact, the in vitro TGF-beta-mediated production of fibronectin, one of the major TGF-beta-regulated extracellular components, has recently been correlated with Rho protein signalling molecules. Although a close relationship between increased renal tissue levels of TGF-beta1 and fibronectin has been reported in IgA nephropathy, no data are available on renal tissue expression of Rho proteins.

METHODS

This study was designed to assess in IgA nephropathy patients the kidney tissue immunohistochemical expression of RhoA, TGF-beta1, and fibronectin, and the rate of immunoreactivity for each antigen by image analysis.

RESULTS

An increase in RhoA, TGF-beta1, and fibronectin expression was detected in tubulointerstitium and in glomeruli of IgA nephropathy compared to normal kidneys; in particular, RhoA was found also in proximal tubules, unlike control kidneys and mainly at the cell boundary level, which is in keeping with its activated form. The image analysis confirmed that the kidney tissue levels of RhoA, TGF-beta1, and fibronectin were significantly enhanced in the patients.

CONCLUSION

This study suggests that RhoA may represent a key molecule in the signalling transduction pathway of profibrotic signals in IgA nephropathy.

Proteinuria and growth factors in the development of tubulointerstitial injury and scarring in kidney disease

PURPOSE OF REVIEW

There are ongoing debates as to the role and mechanisms of proteinuria in tubulointerstitial fibrogenesis. Moreover, recent experimental findings have allowed for further insights into mediators and interactions between cells in the renal interstitium during fibrogenesis.

RECENT FINDINGS

Proteinuria or albuminuria are likely just markers for the glomerular ultrafiltration and tubular actions of ultrafiltered, biologically active growth factors which 'activate' tubular cells causing basolateral secretion of chemokines and cytokines. Chemokines attract and activate macrophages. Tubular cell-derived platelet-derived growth factor (PDGF) and macrophage-derived transforming growth factor-beta cause fibroblast proliferation. Several growth factors contribute to their transition into extracellular matrix-producing myofibroblasts. This cascade of events provides targets for some currently available and several novel therapies.

SUMMARY

Albuminuria or glomerular proteinuria appear to be markers but ultrafiltered, bioactive growth factors are culprits in proteinuria-associated interstitial fibrosis. Interactions of tubular cells with macrophages and fibroblasts in the interstitium via defined growth factor/cytokines provide opportunities for therapeutic interventions.

Long-term dual blockade with candesartan and lisinopril in hypertensive patients with diabetes: the CALM II study

OBJECTIVE

To assess and compare the long-term effects of the combination of candesartan and lisinopril with high-dose lisinopril on systolic blood pressure in patients with hypertension and diabetes.

RESEARCH DESIGN AND METHODS

This was a prospective, randomized, parallel-group, double-blind, double-dummy study with a 12-month follow-up. Drug therapy was either lisinopril 40 mg once daily or dual-blockade treatment with candesartan 16 mg once daily and lisinopril 20 mg once daily. The study comprised 75 type 1 and type 2 diabetic patients aged 35-74 years. The main outcome measures were seated and 24-h ambulatory systolic blood pressure.

RESULTS

Reduction in systolic blood pressure (24-h systolic blood pressure) reduction was obtained in both treatment arms (mean reduction at final follow-up: dual blockade 6 mmHg vs. lisinopril 2 mmHg), but no significant difference was found between dual-blockade and lisinopril 40 mg once daily (P = 0.10). Both treatments were generally well tolerated, and similar low rates of side effects were found in the two groups.

CONCLUSIONS

There was no statistically significant difference between lisinopril 40 mg once daily and lisinopril 20 mg in combination with candesartan 16 mg once daily in reducing systolic blood pressure in hypertensive patients with diabetes.

Combined therapy of enalapril and losartan attenuates histologic progression in immunoglobulin A nephropathy

BACKGROUND

It has been reported that combined therapy of angiotensin converting enzyme inhibitor and angiotensin receptor blocker significantly decreases proteinuria in immunoglobulin A (IgA) nephropathy. However, histologic alterations following the therapy have not been reported.

METHODS

A total of nine Japanese children with severe proteinuric IgA nephropathy who received a prompt immunosuppressive therapy were enrolled the study, four of whom received a combined therapy of angiotensin converting enzyme inhibitor, enalapril and angiotensin receptor blocker, losartan (Group A), while the remaining five did not (Group B). All underwent renal biopsy before and approximately 12 months after the first renal biopsy.

RESULTS

At presentation, urine protein excretion and the histologic indices of mean activity index, mean chronicity index and tubulointerstitial scores did not show a statistical difference between the two groups: Group A (2.6 +/- 0.6 g/day; mean activity index, 5.0 +/- 1.0; mean chronicity index, 5.0 +/- 1.0; tubulointerstitial scores, 4.3 +/- 1.0) and Group B (2.2 +/- 0.6 g/day; mean activity index, 4.8 +/- 0.8; mean chronicity index, 4.8 +/- 1.3; tubulointerstitial scores, 3.6 +/- 0.5, respectively). All had normal blood pressure and renal function. Urine protein excretion and the activity index decreased at the second renal biopsy, while the chronicity index and the tubulointerstitial scores slightly increased or remained unchanged. In comparison with Group B, a significant suppression in increasing the chronicity index and the tubulointerstitial scores obtained at the second renal biopsy were observed in Group A [Group A: 4.3 +/- 1.2 and 3.0 +/- 0.0, respectively, vs Group B: 6.0 +/- 0.7 and 4.4 +/- 0.9, respectively (P < 0.05)]. One patient in Group B developed chronic renal insufficiency thereafter.

CONCLUSIONS

Although only a small number of patients were examined, these clinical findings suggest that a combined therapy of enalapril and losartan may attenuate histologic progression in at least a proportion of patients with severe proteinuric IgA nephropathy.

Dual blockade of the renin angiotensin system in diabetic and nondiabetic kidney disease

Dual blockade of the renin angiotensin system is based on a principle of obtaining the broadest and most efficient blockade of the effects of angiotensin II, by using the combination of an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II-receptor blocker (ARB). By combining two, different pharmacologic principles and inhibiting both the ACE and the angiotensin II type 1 receptor, it seems possible to block both the production and the action of angiotensin II, which would serve as efficient antihypertensive therapy. Exploring the beneficial effects of dual-blockade therapy is a work in rapid progress, in both diabetic and non-diabetic nephropathy. But evidence is also emerging in cardiovascular medicine, an overview of which is provided in this article.