Renin-angiotensin system dual blockade using angiotensin receptor plus aliskiren decreases severe proteinuria in kidney transplant recipients

Treatment of Hypertension Because of Immunosuppressive Therapy After Solid Organ Transplantation-Pharmacological Approach

ABSTRACT

Solid organs transplantation procedures have been performed for more than half a century. Growing knowledge of immune response and development of new immunosuppressive regimens guarantee more and more successful outcomes. However, many of the applied drugs lead to cardiovascular complications, the most frequent of which is hypertension. This article describes epidemiology, pathogenetic mechanisms, and treatment of hypertension induced by immunosuppressive medication. The main impact is focused on drugs belonging to the following groups: calcineurin inhibitors, the inhibitors of the mammalian target of rapamycin, and glucocorticosteroids. We analyze the mechanism of action of the main hypertensive drugs and their influence on the reversing hypertonic action of the immunosuppressive agents. In the absence of current guidelines addressing this problem, this article is an attempt to fill the gap, helping clinicians to choose proper medication.

Direct inhibition of plasmatic renin activity with aliskiren: a promising but under-investigated therapeutic option for non-diabetic glomerulonephritis

Non-diabetic glomerulonephritis is a frequent cause of end-stage renal disease. The use of renin-angiotensin-aldosterone system blockers is a fundamental therapeutic approach. However, converting enzyme inhibitors (ACE-is) and angiotensin receptor blockers do not always achieve the desired target of proteinuria. The induction of the prorenin and renin up-regulation is a possible explanation. Aliskiren is the first drug acting as direct inhibitor of plasmatic renin activity, also able to interfere with the prorenin and renin profibrotic escape. We aimed at reviewing the literature for the assessment of potential efficacy and safety of aliskiren in the treatment of non-diabetic glomerulonephritis. The data on this topic are limited; however, we concluded for a possible usefulness of aliskiren. The renal safety profile appears potentially acceptable in non-diabetic patients although extreme carefulness, particularly with respect to long-term renal and cardiovascular tolerability, is recommended.

The Decrement of Hemoglobin Concentration with Angiotensin II Receptor Blocker Treatment Is Correlated with the Reduction of Albuminuria in Non-Diabetic Hypertensive Patients: Post-Hoc Analysis of ESPECIAL Trial

Blockade of the renin-angiotensin-aldosterone system exhibits a renoprotective effect; however, blockade of this system may also decrease hemoglobin (Hb) and erythropoietin (EPO) levels. We evaluated the correlation between reduced albuminuria and decreased hemoglobin concentrations after treatment with an angiotensin II receptor blocker (ARB). Two hundred forty-five non-diabetic hypertensive participants with established albuminuria and relatively preserved renal function were treated with an ARB (40 mg/day olmesartan) for eight weeks. Subsequent changes in various clinical parameters, including Hb, EPO, and albuminuria, were analyzed following treatment. After the 8-week treatment with an ARB, Hb and EPO levels significantly decreased. Patients with a greater decrease in Hb exhibited a greater reduction in 24-hour urinary albumin excretion compared with patients with less of a decrease or no decrease in Hb, whereas no associations with a decline in renal function and EPO levels were noted. Multivariate logistic regression analysis demonstrated a correlation between the reduction of urine albumin excretion and the decrease in Hb levels (after natural logarithm transformation, adjusted odds ratio 1.76, 95% confidence interval 1.21-2.56, P = 0.003). Linear regression analysis also supported this positive correlation (Pearson correlation analysis; R = 0.24, P < 0.001). Decreased Hb concentrations following ARB treatment were positively correlated with reduced albuminuria in non-diabetic hypertensive patients, regardless of decreased blood pressure and EPO levels or renal function decline.

Proteinuria and its relation to cardiovascular disease

Chronic kidney disease (CKD) and its associated morbidity pose a worldwide health problem. As well as risk of endstage renal disease requiring renal replacement therapy, cardiovascular disease is the leading cause of premature death among the CKD population. Proteinuria is a marker of renal injury that can often be detected earlier than any tangible decline in glomerular filtration rate. As well as being a risk marker for decline in renal function, proteinuria is now widely accepted as an independent risk factor for cardiovascular morbidity and mortality. This review will address the prognostic implications of proteinuria in the general population as well as other specific disease states including diabetes, hypertension and heart failure. A variety of pathophysiological mechanisms that may underlie the relationship between renal and cardiovascular disease have been proposed, including insulin resistance, inflammation, and endothelial dysfunction. As proteinuria has evolved into a therapeutic target for cardiovascular risk reduction in the clinical setting we will also review therapeutic strategies that should be considered for patients with persistent proteinuria.

Circulating angiotensin-converting enzyme 2 activity in kidney transplantation: a longitudinal pilot study

BACKGROUND/AIMS

Angiotensin-converting enzyme 2 (ACE2) is the only known active homologue of ACE, and degrades angiotensin (Ang) II and Ang I to Ang(1-7) and Ang(1-9), respectively. The role of ACE2 in kidney transplant (KT) is unknown. Our objective was to investigate circulating ACE2 activity in KT patients, and the relationship between serum ACE2 activity and age, gender, graft function and cardiovascular risk markers in KT patients.

METHODS

113 KT patients with stable graft function were included in this cross-sectional study. Circulating ACE2 activity was assessed using a fluorescent assay.

RESULTS

Circulating ACE2 activity was detectable in KT patients and was increased in KT with ischemic heart disease as compared to KT without ischemic heart disease (105.9 ± 8.7 vs. 97.1 ± 7.05 relative fluorescence units (RFU)/µl/h, p < 0.05). ACE2 activity was increased in male KT as compared to females (105.2 ± 9.1 vs. 84.7 ± 6.9 RFU/µl/h, p = 0.05). ACE2 activity correlated positively with serum creatinine (r = 0.27), serum urea (r = 0.29), age (r = 0.24), aspartate transaminase (r = 0.39), alanine transaminase (r = 0.48), γ-glutamyl transferase (γ-GT) (r = 0.52), age (r = 0.24), and glycosylated hemoglobin (r = 0.19) (p < 0.05). By multiple regression analysis, age, serum creatinine, and serum γ-GT were independent predictors of serum ACE2 activity (r = 0.66, p < 0.001).

CONCLUSIONS

Circulating ACE2 activity is measurable in KT patients and directly correlates with age, renal allograft and liver function parameters. These findings suggest that measurement of serum ACE2 may be used as a non-invasive marker to understand the role of the renin-angiotensin system in KT patients.

Effect of add-on direct renin inhibitor aliskiren in patients with non-diabetes related chronic kidney disease

Background

The renin-angiotensin-aldosterone system (RAAS) plays an important role in the progression of chronic kidney disease (CKD). Although dual RAAS inhibition results in worse renal outcomes than monotherapy in high risk type 2 diabetes patients, the effect of dual RAAS inhibition in patients with non-DM CKD is unclear. The aim of this study was to evaluate the potential renoprotective effect of add-on direct renin inhibitor in non-DM CKD patients.

Methods

We retrospectively enrolled 189 non-DM CKD patients who had been taking angiotensin II receptor blockers (ARBs) for more than six months. Patients were divided into an add-on aliskiren group and an ARB monotherapy group. The primary outcomes were a decline in glomerular filtration rate (GFR) and a reduction in urinary protein-to-creatinine ratio at six months.

Results

The baseline characteristics of the two groups were similar. Aliskiren 150 mg daily reduced the urinary protein-to-creatinine ratio by 26% (95% confidence interval, 15 to 37%; p < 0.001). The decline in GFR was smaller in the add-on aliskiren group (−2.1 vs. -4.0 ml/min, p = 0.038). Add-on aliskiren had a neutral effect on serum potassium in the non-DM CKD patients. In subgroup analysis, the proteinuria-reducing effect of aliskiren was more prominent in patients with a GFR less than 60 ml/min, and in patients with a urinary protein-to-creatinine ratio greater than 1.8. The effect of aliskiren in retarding the decline in GFR was more prominent in patients with hypertensive nephropathy than in those with glomerulonephritis.

Conclusion

Add-on direct renin inhibitor aliskiren (150 mg daily) safely reduced proteinuria and attenuated the decline in GFR in the non-DM CKD patients who were receiving ARBs.

Comparative effect of angiotensin II type I receptor blockers and calcium channel blockers on laboratory parameters in hypertensive patients with type 2 diabetes

BACKGROUND

Both angiotensin II type I receptor blockers (ARBs) and calcium channel blockers (CCBs) are widely used antihypertensive drugs. Many clinical studies have demonstrated and compared the organ-protection effects and adverse events of these drugs. However, few large-scale studies have focused on the effect of these drugs as monotherapy on laboratory parameters. We evaluated and compared the effects of ARB and CCB monotherapy on clinical laboratory parameters in patients with concomitant hypertension and type 2 diabetes mellitus.

METHODS

We used data from the Clinical Data Warehouse of Nihon University School of Medicine obtained between Nov 1, 2004 and July 31, 2011, to identify cohorts of new ARB users (n = 601) and propensity-score matched new CCB users (n = 601), with concomitant mild to moderate hypertension and type 2 diabetes mellitus. We used a multivariate-adjusted regression model to adjust for differences between ARB and CCB users, and compared laboratory parameters including serum levels of triglyceride (TG), total cholesterol (TC), non-fasting blood glucose, hemoglobin A1c (HbA1c), sodium, potassium, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), hemoglobin and hematocrit, and white blood cell (WBC), red blood cell (RBC) and platelet (PLT) counts up to 12 months after the start of ARB or CCB monotherapy.

RESULTS

We found a significant reduction of serum TC, HbA1c, hemoglobin and hematocrit and RBC count and a significant increase of serum potassium in ARB users, and a reduction of serum TC and hemoglobin in CCB users, from the baseline period to the exposure period. The reductions of RBC count, hemoglobin and hematocrit in ARB users were significantly greater than those in CCB users. The increase of serum potassium in ARB users was significantly greater than that in CCB users.

CONCLUSIONS

Our study suggested that hematological adverse effects and electrolyte imbalance are greater with ARB monotherapy than with CCB monotherapy.

New options and perspectives for proteinuria management after kidney transplantation

Proteinuria has been strongly correlated with reduced function and graft survival in kidney-transplanted patients. Data regarding new strategies in proteinuria treatment and subsequent allograft survival are lacking. Similarities between chronic graft injury and chronic kidney disease (CKD) suggest that the same therapeutic antiproteinuric tools should be effective in kidney-transplanted patients. The classic strategies to decrease proteinuria such as blood pressure control, nicotine cessation, low-salt diet, and maintaining an ideal body weight seem to be not enough to achieve proteinuria control. Improvements in our understanding of the pathogenesis of CKD have led to the identification of several novel targets for proteinuria management. In this review, we discuss novel pharmacological approaches that aim to decrease proteinuria in CKD patients, including the use of direct renin inhibitors, vitamin D analogs, pentoxifylline, and endothelin receptor antagonists. We also discuss the promise of using antifibrotic agents to treat proteinuria. The identification of new biomarkers of CKD and its progression can help in the selection of the most effective treatment for decreasing proteinuria and maintaining kidney function.

Aliskiren as a novel therapeutic agent for hypertension and cardio-renal diseases

Objectives

High blood pressure (BP) is a major risk factor for cardiovascular and renal complications. A majority of treated hypertensive patients still complain of high BP. The renin-angiotensin aldosterone system (RAAS) has been a centre-stage target for all the cardiovascular and cardio-renal complications. Aliskiren, is the first direct renin inhibitor (DRI) to be approved by the US FDA. Renin controls the rate-limiting step in the RAAS cascade and hence is the most favorable target for RAAS suppression.

Key findings

This review article strives to summarize the pharmacokinetic, preclinical and clinical studies done so far pertaining to the efficacy of aliskiren. Further, the pharmacology of aliskiren has been comprehensively dealt with to enhance understanding so as to further research in this unfathomed area in the multitude of cardiovascular disorders and renal diseases.

Summary

Aliskiren has been shown to have comparable BP-lowering effects to other RAAS inhibitors. Recent clinical trials have indicated that it might contribute significantly in combination with other agents for the protection of end-organ diseases.