Direct Renin Inhibition with Aliskiren in Hypertension and Target Organ Damage

Molecular Interactions of Arterial Hypertension in Its Target Organs

Arterial hypertension (AH) is a major risk factor for the development of cardiovascular diseases. It is estimated that the disease affects between 10% and 20% of the adult population and is responsible for 5.8% of all deaths worldwide. Several pathophysiologic factors are crucial in AH, including inappropriate activation of the renin-angiotensin-aldosterone system, oxidative stress and inflammation. The heart, kidney, brain, retina and arterial blood vessels are prime targets of hypertensive damage. Uncontrolled and untreated AH accelerates the damage to these organs and could cause their failure. Damage to these organs could also manifest as coronary heart disease, cognitive impairment, retinopathy or optic neuropathy. For better understanding, it is important to analyze molecular factors which take part in pathogenesis of AH and hypertension-related target organ damage. In our paper, we would like to focus on molecular interactions of AH in the heart, blood vessels, brain and kidneys. We focus on matrix metalloproteinases, the role of immune system, the renin-angiotensin-aldosterone system and oxidative stress in hypertensive induced organ damage.

The Anti-Inflammatory Effect of Different Doses of Aliskiren in Rat Models of Inflammation

OBJECTIVE

The present study was designed to evaluate the anti-inflammatory effects of different doses of aliskiren in two animal models of inflammation.

METHODOLOGY

Sixty-six Wistar rats were allocated into five groups: the first group (six rats) was treated with the vehicle only, without induction of paw edema and granulomatous inflammation, and served as a negative control; the second group (12 rats) was allocated into two subgroups and treated with the vehicle only, with induction of paw edema and granulomatous inflammation, and served as a positive control; the third group (36 rats) was allocated into six subgroups and treated with different doses of aliskiren (15, 30, and 60 mg/kg) in both models; the fourth group (12 rats) was treated with dexamethasone (1 mg/kg) in both models of inflammation. Serum concentrations of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), vascular cell adhesion molecule-1 (VCAM-1), and high sensitivity C-reactive protein (hs-CRP) were measured. Skin samples were also sent for histopathological examination.

RESULTS

Aliskiren, in a dose-dependent pattern, significantly decreased inflammation in rat models of inflammation, by attenuating the percentage of exudate, granuloma, and paw edema. Furthermore, it significantly reduced serum concentrations of TNF-α, VCAM-1, and hs-CRP and restored the serum concentration of IL-10. Additionally, significant improvement was seen in the histopathological findings.

CONCLUSION

In the current study, aliskiren was successful in decreasing inflammation in both models. These findings suggest that aliskiren is a good candidate for the treatment of inflammatory diseases.

Uso terapéutico de los inhibidores de la enzima convertidora de angiotensina en pacientes con COVID-19: las «dos caras de la moneda»

La evidencia actual es limitada para determinar el impacto del uso de los inhibidores de la enzima convertidora de angiotensina (IECA) en la predisposición al empeoramiento de la enfermedad del coronavirus 2019 (COVID-19). Inicialmente se reportó que en los pacientes con progresión grave de la COVID-19 existía una mortalidad elevada, los cuales tenían antecedentes de hipertensión arterial, diabetes mellitus, enfermedad cardiovascular y enfermedad renal crónica. Parte de estos pacientes también tenía en común que utilizaban IECA, lo cual alertó a la comunidad médica sobre su riesgo potencial en coexistencia con COVID-19. Sin embargo, estudios más recientes de casos-controles encontraron que los inhibidores del sistema renina-angiotensina, incluyendo los IECA, no incrementan el riesgo de COVID-19 o de requerir admisión hospitalaria por esta causa. Diferentes revistas científicas han facilitado el acceso a reportes preliminares, dejando a discreción de la comunidad médica y científica hacer uso de dicha información para promover el desarrollo de estudios que confirmen experimentalmente dichos hallazgos, preclínicos y epidemiológicos, que finalmente impacten en las decisiones de la práctica clínica para beneficiar a los pacientes con COVID-19. En esta revisión de la literatura se exploran los diferentes efectos mediados por los IECA que podrían estar relacionados con la respuesta inmune durante la infección y la transmisión de COVID-19, compilando evidencia disponible que evalúa si en realidad representan un riesgo o si, por el contrario, confieren un efecto protector.

Aliskiren improves renal morphophysiology and inflammation in Wistar rats with 2K1C renovascular hypertension

Hypertension is characterized by persistent elevated blood pressure levels, one of the leading causes of death in the world. Renovascular hypertension represents the most common cause of secondary hypertension, and its progress is associated with overactivation of the renin angiotensin aldosterone system (RAAS), causing systemic and local changes. Aliskiren is a renin-inhibiting drug that optimizes RAAS suppression. In this sense, the objective of the present study was to analyze the morphophysiology of the left kidney in Wistar rats with renovascular hypertension after treatment with Aliskiren. Parameters such as systolic blood pressure, urinary creatinine and protein excretion, renal cortex structure and ultrastructure, fibrosis and tissue inflammation were analyzed. Our results showed that the hypertensive animals treated with Aliskiren presented a reestablishment of blood pressure, expression of renin, and renal function, as well as a remodeling of morphological alterations through the reduction of fibrosis. The treatment regulated the laminin expression and decreased pro-inflammatory cytokines, restoring the integrity of the glomerular filtration barrier. Therefore, our findings suggest that Aliskiren has a renoprotective effect acting on the improvement of the morphology, physiology and pathology of the renal cortex of animals with renovascular hypertension.

Renin Activity in Heart Failure with Reduced Systolic Function-New Insights

Regardless of the cause, symptomatic heart failure (HF) with reduced ejection fraction (rEF) is characterized by pathological activation of the renin–angiotensin–aldosterone system (RAAS) with sodium retention and extracellular fluid expansion (edema). Here, we review the role of active renin, a crucial, upstream enzymatic regulator of the RAAS, as a prognostic and diagnostic plasma biomarker of heart failure with reduced ejection fraction (HFrEF) progression; we also discuss its potential as a pharmacological bio-target in HF therapy. Clinical and experimental studies indicate that plasma renin activity is elevated with symptomatic HFrEF with edema in patients, as well as in companion animals and experimental models of HF. Plasma renin activity levels are also reported to be elevated in patients and animals with rEF before the development of symptomatic HF. Modulation of renin activity in experimental HF significantly reduces edema formation and the progression of systolic dysfunction and improves survival. Thus, specific assessment and targeting of elevated renin activity may enhance diagnostic and therapeutic precision to improve outcomes in appropriate patients with HFrEF.

Wnt/β-catenin regulates blood pressure and kidney injury in rats

Activation of the renin-angiotensin system (RAS) plays a pivotal role in mediating hypertension, chronic kidney and cardiovascular diseases. As Wnt/β-catenin regulates multiple RAS genes, we speculated that this developmental signaling pathway might also participate in blood pressure (BP) regulation. To test this, we utilized two rat models of experimental hypertension: chronic angiotensin II infusion and remnant kidney after 5/6 nephrectomy. Inhibition of Wnt/β-catenin by ICG-001 blunted angiotensin II-induced hypertension. Interestingly, angiotensin II was able to induce the expression of multiple Wnt genes in vivo and in vitro, thereby creating a vicious cycle between Wnt/β-catenin and RAS activation. In the remnant kidney model, renal β-catenin was upregulated, and delayed administration of ICG-001 also blunted BP elevation and abolished the induction of angiotensinogen, renin, angiotensin-converting enzyme and angiotensin II type 1 receptor. ICG-001 also reduced albuminuria, serum creatinine and blood urea nitrogen, and inhibited renal expression of fibronectin, collagen I and plasminogen activator inhibitor-1, and suppressed the infiltration of CD3⁺ T cells and CD68⁺ monocytes/macrophages. In vitro, incubation with losartan prevented Wnt/β-catenin-mediated fibronectin, α-smooth muscle actin and Snail1 expression, suggesting that the fibrogenic action of Wnt/β-catenin is dependent on RAS activation. Taken together, these results suggest an intrinsic linkage of Wnt/β-catenin signaling with BP regulation. Our studies also demonstrate that hyperactive Wnt/β-catenin can drive hypertension and kidney damage via RAS activation.

Renin-angiotensin inhibitors reprogram tumor immune microenvironment: A comprehensive view of the influences on anti-tumor immunity

Renin-angiotensin system inhibitors (RASi) have shown potential anti-tumor effects that may have a significant impact in cancer therapy. The components of the renin-angiotensin system (RAS) including both, conventional and alternative axis, appear to have contradictory effects on tumor biology. The mechanisms by which RASi impair tumor growth extend beyond their function of modulating tumor vasculature. The major focus of this review is to analyze other mechanisms by which RASi reprogram the tumor immune microenvironment. These involve impairing hypoxia and acidosis within the tumor stroma, regulating inflammatory signaling pathways and oxidative stress, modulating the function of the non-cellular components and immune cells, and regulating the cross-talk between kalli krein kinin system and RAS.

Molecular and genetic aspects of guanylyl cyclase natriuretic peptide receptor-A in regulation of blood pressure and renal function

Natriuretic peptides (NPs) exert diverse effects on several biological and physiological systems, such as kidney function, neural and endocrine signaling, energy metabolism, and cardiovascular function, playing pivotal roles in the regulation of blood pressure (BP) and cardiac and vascular homeostasis. NPs are collectively known as anti-hypertensive hormones and their main functions are directed toward eliciting natriuretic/diuretic, vasorelaxant, anti-proliferative, anti-inflammatory, and anti-hypertrophic effects, thereby, regulating the fluid volume, BP, and renal and cardiovascular conditions. Interactions of NPs with their cognate receptors display a central role in all aspects of cellular, biochemical, and molecular mechanisms that govern physiology and pathophysiology of BP and cardiovascular events. Among the NPs atrial and brain natriuretic peptides (ANP and BNP) activate guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) and initiate intracellular signaling. The genetic disruption of Npr1 (encoding GC-A/NPRA) in mice exhibits high BP and hypertensive heart disease that is seen in untreated hypertensive subjects, including high BP and heart failure. There has been a surge of interest in the NPs and their receptors and a wealth of information have emerged in the last four decades, including molecular structure, signaling mechanisms, altered phenotypic characterization of transgenic and gene-targeted animal models, and genetic analyses in humans. The major goal of the present review is to emphasize and summarize the critical findings and recent discoveries regarding the molecular and genetic regulation of NPs, physiological metabolic functions, and the signaling of receptor GC-A/NPRA with emphasis on the BP regulation and renal and cardiovascular disorders.

Intervention using vitamin D for elevated urinary albumin in type 2 diabetes mellitus (IDEAL-2 Study): study protocol for a randomised controlled trial

Background

The prevalence of type 2 diabetes mellitus (T2DM) is increasing worldwide. T2DM is associated with serious macro- and microvascular complications. In particular, diabetic kidney disease (DKD), which begins with excessive urinary albumin excretion, has a significant impact on affected individuals and is costly to healthcare services. Inhibition of the renin–angiotensin–aldosterone system (RAAS) with angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) significantly reduces albuminuria in diabetes, but this effect is not observed in all those treated. Active vitamin D analogues have been observed to be reno-protective through inhibition of RAAS in animal and human studies. Therefore, it can be hypothesised that an active vitamin D analogue will have an additional benefit to ACEI/ARB treatment for albuminuria reduction in DKD.

Methods

The planned study is an ongoing non-blinded randomised controlled parallel-group trial examining the impact, in individuals with T2DM, of the addition of bioactive vitamin D (calcitriol) to RAAS inhibition treatment using ACI or ARB on urinary albumin excretion over a period of 26 weeks. The primary outcome measure is the urinary albumin creatinine ratio. It is planned for the study to recruit 320 participants. Other outcome measures of interest include 24-h urine albumin (24 h UA) excretion, estimated glomerular filtration rate (eGFR), blood pressure and quality of life. Safety will be assessed throughout.

Discussion

If the addition of calcitriol to RAAS inhibition with ACEI or ARB safely results in a significant reduction in albuminuria, the study adds to the body of evidence supporting a role for vitamin D in reno-protection, will inform clinical practice and could result in significant reduction of healthcare costs associated with DKD.

Trial registration

ISRCTN, ISRCTN86739609. Registered on 7 June 2017. ClinicalTrials.gov, NCT03216564. Registered on 13 July 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2616-5) contains supplementary material, which is available to authorized users.

Tocotrienol is a cardioprotective agent against ageing-associated cardiovascular disease and its associated morbidities

Ageing is a nonmodifiable risk factor that is linked to increased likelihood of cardiovascular morbidities. Whilst many pharmacological interventions currently exist to treat many of these disorders such as statins for hypercholesterolemia or beta-blockers for hypertension, the elderly appear to present a greater likelihood of suffering non-related side effects such as increased risk of developing new onset type 2 diabetes (NODM). In some cases, lower efficacy in the elderly have also been reported. Alternative forms of treatment have been sought to address these issues, and there has been a growing interest in looking at herbal remedies or plant-based natural compounds. Oxidative stress and inflammation are implicated in the manifestation of ageing-related cardiovascular disease. Thus, it is natural that a compound that possesses both antioxidative and anti-inflammatory bioactivities would be considered. This review article examines the potential of tocotrienols, a class of Vitamin E compounds with proven superior antioxidative and anti-inflammatory activity compared to tocopherols (the other class of Vitamin E compounds), in ameliorating ageing-related cardiovascular diseases and its associated morbidities. In particular, the potential of tocotrienols in improving inflammaging, dyslipidemia and mitochondrial dysfunction in ageing-related cardiovascular diseases are discussed.

New therapeutic agents in diabetic nephropathy

Studies investigating diabetic nephropathy (DN) have mostly focused on interpreting the pathologic molecular mechanisms of DN, which may provide valuable tools for early diagnosis and prevention of disease onset and progression. Currently, there are few therapeutic drugs for DN, which mainly consist of antihypertensive and antiproteinuric measures that arise from strict renin-angiotensin-aldosterone system inactivation. However, these traditional therapies are suboptimal and there is a clear, unmet need for treatments that offer effective schemes beyond glucose control. The complexity and heterogeneity of the DN entity, along with ambiguous renal endpoints that may deter accurate appraisal of new drug potency, contribute to a worsening of the situation. To address these issues, current research into original therapies to treat DN is focusing on the intrinsic renal pathways that intervene with intracellular signaling of anti-inflammatory, antifibrotic, and metabolic pathways. Mounting evidence in support of the favorable metabolic effects of these novel agents with respect to the renal aspects of DN supports the likelihood of systemic beneficial effects as well. Thus, when translated into clinical use, these novel agents would also address the comorbid factors associated with diabetes, such as obesity and risk of cardiovascular disease. This review will provide a discussion of the promising and effective therapeutic agents for the management of DN.

Antihypertensive Efficacy of the Direct Renin Inhibitor Aliskiren as Add-on Therapy in Patients with Poorly Controlled Hypertension

OBJECTIVE

A direct renin inhibitor, aliskiren, has a longer stable antihypertensive effect compared with other renin-angiotensin-aldosterone system (RAAS) inhibitors.

METHODS

This study was a 6-month, single-center, open trial conducted between December 2010 and November 2011 to assess the antihypertensive effect of adding aliskiren (300 mg) to the treatment of essential hypertension patients whose target blood pressure (BP) had not been achieved and to assess whether it was possible to reduce the amount of antihypertensive drugs used.

RESULTS

The results showed an overall improvement in the target BP achievement rate of 60% for clinic BP and 52% for home BP measurements (75 cases total). The mean number of drugs before treatment with aliskiren was 3.28±1.52, whereas at the end of the six months the mean number of drugs prescribed other than aliskiren was 2.85±1.72 (p<0.0001). Moreover, no worsening of the renal function was observed in patients with diabetes or chronic kidney disease (CKD) who were being treated with other RAAS inhibitors in combination to aliskiren.

CONCLUSION

These results showed that when aliskiren was added to the treatment of poorly controlled hypertension, the BP achievement rate increased, and it was possible to reduce the amount of antihypertensive drugs used in combination with aliskiren. Moreover, as a result of careful monitoring of the renal function or decreasing the amounts of drugs used in combination, no worsening of the renal function was observed even in the cases complicated by diabetes or CKD being treated with other RAAS inhibitors.

Mesenchymal Stromal Cells Prevent Renal Fibrosis in a Rat Model of Unilateral Ureteral Obstruction by Suppressing the Renin-Angiotensin System via HuR

We studied Mesenchymal Stromal Cells (MSC) effects in experimental Unilateral Ureteral Obstruction (UUO), a fibrogenic renal disease. Rats were divided in 5 groups: sham, UUO, MSC treated-UUO, ACEi treated-UUO, MSC+ACEi treated- UUO. Data were collected at 1, 7, 21 days. UUO induced monocyte renal infiltration, tubular cell apoptosis, tubular atrophy, interstitial fibrosis and overexpression of TGFβ, Renin mRNA (RENmRNA), increase of Renin, Angiotensin II (AII) and aldosterone serum levels. Both lisinopril (ACEi) and MSC treatment prevented monocyte infiltration, reduced tubular cell apoptosis, renal fibrosis and TGFβ expression. Combined therapy provided a further suppression of monocyte infiltration and tubular injury. Lisinopril alone caused a rebound activation of Renin-Angiotensin System (RAS), while MSC suppressed RENmRNA and Renin synthesis and induced a decrease of AII and aldosterone serum levels. Furthermore, in in-vitro and in-vivo experiments, MSC inhibit Human antigen R (HuR) trascription, an enhancer of RENmRNA stability by IL10 release. In conclusion, we demonstrate that in UUO MSC prevent fibrosis, by decreasing HuR-dependent RENmRNA stability. Our findings give a clue to understand the molecular mechanism through which MSC may prevent fibrosis in a wide and heterogeneous number of diseases that share RAS activation as common upstream pathogenic mechanism.

Successful treatment of hypertension in anuric hemodialysis patients with a direct Renin inhibitor, aliskiren

OBJECTIVE

A direct renin-inhibitor (DRI), aliskiren, was administered to anuric patients to investigate whether it can be a new optional therapy against hypertension in hemodialysis (HD) patients.

PATIENTS

The patients that received aliskiren comprised 8 males and 2 females with a mean ± SD age of 63 ± 8 years (43-72 years). They were exposed to dialysis therapy for 118 ± 73 months (8-251 months), with diabetes mellitus in 4 cases, chronic glomerulonephritis in 4 cases, and other diagnoses in 2 cases.

METHODS

After the plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured before an HD session, aliskiren, 150 mg as an initial dose, was administered to the patients. PRA and PAC were also examined a week after initiating aliskiren. The blood pressure (BP) levels at the start of each HD session for a period of 2 weeks (6 HD sessions) were compared between before and after administration of aliskiren. The change of doses in other antihypertensive agents was also counted.

RESULTS

The averaged reduction of mean blood pressure was 4 ± 5 mmHg, and doses of antihypertensives other than aliskiren were reduced in 4 patients. Of the examined parameters, only the reduction rate of PRA x PAC seemed correlated with the BP lowering effect of aliskiren, which was calculated as the sum of the mean BP reduction in mmHg and drug reduction with 1 tablet (capsule)/day considered to be 10 mmHg.

CONCLUSION

A DRI, aliskiren, was effective even in anuric dialysis patients, and monitoring of PRA and PAC was valuable for selecting cases responsive to aliskiren.

Renin-angiotensin system (RAS) blockade attenuates growth and metastatic potential of renal cell carcinoma in mice

OBJECTIVES

Renal cell carcinoma (RCC) is the most frequent type of cancer among renal neoplasms in adults and responds poorly to radiotherapy and chemotherapy. There is evidence that blockade of the renin-angiotensin system (RAS) might have antineoplastic effects. The aim of this study was to investigate the effects of RAS blockade on RCC in a murine model.

METHODS AND MATERIALS

Murine renal cancer cells (Renca) were injected (1 × 10(5)) into the subcapsular space of the left kidney of BALB/c mice (8 wk of age). The animals were divided into 4 groups: a control group (no treatment), angiotensin-receptor blockers group (losartan 100mg/kg/d), angiotensin-converting enzyme inhibitor group (captopril 10mg/kg/d), and angiotensin-receptor blockers +angiotensin-converting enzyme inhibitor group (losartan 100mg/kg/d +captopril 10mg/kg/d). The animals received the drugs by gavage for 21 days after inoculation, beginning 2 days before tumor induction, and were then euthanized. After killing the animals, the kidneys and lungs were removed, weighed, and processed for histopathological and immunohistochemical analyses. Angiogenesis and vascular microvessels were assessed with the antibodies anti-vascular endothelial growth factor and anti-CD34.

RESULTS

Angiotensin II-inoculated animals developed renal tumors. Treated animals presented smaller tumors, regardless of the therapeutic regimen, and far fewer lung metastases in both quantity and dimension compared with the controls. The expression of vascular endothelial growth factor and CD34 were significantly decreased in renal tumors of treated animals compared with the controls.

CONCLUSIONS

Our findings suggest that blockade of RAS decreases tumor proliferation and metastatic capacity of RCC in this experimental model.

Protective effects of aliskiren on atrial ionic remodeling in a canine model of rapid atrial pacing

PURPOSE

Aliskiren inhibits the activation of the renin-angiotensin system. Here, we investigated the effects of aliskiren on chronic atrial iron remodeling in the experimental canine model of rapid atrial pacing.

METHODS

Twenty-eight dogs were assigned to sham (S), control paced (C), paced + aliskiren (10 mg Kg(-1) d(-1), A1), and paced + aliskiren (20 mg Kg(-1) d(-1), A2) groups. Rapid atrial pacing at 500 bpm was maintained for 2 weeks, while group S was not paced. Levels of serum angiotensin-converting enzyme and angiotensin II after pacing were determined by ELISA. Whole-cell patch-clamp technique, western blot, and RT-PCR were applied to assess atrial ionic remodeling.

RESULTS

The density of I CaL and I Na currents (pA/pF) was significantly lower in group C compared with group S (I CaL: -4.09 ± 1.46 vs. -6.12 ± 0.58,P < 0.05; I Na: 30.48 ± 6.08 vs. 46.31 ± 4.73, P < 0.05). However, the high dose of aliskiren elevated the density of I CaL and I Na currents compared with group C (I CaL: -6.23 ± 1.35 vs. -4.09 ± 1.46, P < 0.05; I Na: 58.62 ± 16.17 vs. 30.48 ± 6.08, P < 0.01). The relative mRNA and protein expression levels of Cav1.2 and Nav1.5α were downregulated in group C respectively (Cav1.2: 0.46 ± 0.08; Nav1.5α: 0.52 ± 0.08, P < 0.01; Cav1.2: 0.31 ± 0.03; Nav1.5α: 0.41 ± 0.04, P < 0.01;), but were upregulated by aliskiren.

CONCLUSIONS

Aliskiren has protective effects on atrial tachycardia-induced atrial ionic remodeling.

Effects of a Long-Term Treatment With Aliskiren or Ramipril on Structural Alterations of Subcutaneous Small-Resistance Arteries of Diabetic Hypertensive Patients

Structural alterations of subcutaneous small-resistance arteries are associated with a worse clinical prognosis in hypertension and non–insulin-dependent diabetes mellitus. The effects of the direct renin inhibitor aliskiren on microvascular structure were never previously evaluated. Therefore, we investigated the effects of aliskiren in comparison with those of an extensively used angiotensin-converting enzyme inhibitor, ramipril, on peripheral subcutaneous small-resistance artery morphology, retinal arteriolar structure, and capillary density in a population of patients with non–insulin-dependent diabetes mellitus. Sixteen patients with mild essential hypertension and with a previous diagnosis of non–insulin-dependent diabetes mellitus were included in the study. Patients were then randomized to 1 of the 2 active treatments (aliskiren 150 mg once daily, n=9; or ramipril 5 mg once daily, n=7). Each patient underwent a biopsy of the subcutaneous fat from the gluteal region, an evaluation of retinal artery morphology (scanning laser Doppler flowmetry), and capillary density (capillaroscopy), at baseline and after 1 year of treatment. Subcutaneous small arteries were dissected and mounted on a pressurized micromyograph, and the media-to-lumen ratio was evaluated. A similar office blood pressure–lowering effect and a similar reduction of the wall-to-lumen ratio of retinal arterioles were observed with the 2 drugs. Aliskiren significantly reduced media-to-lumen ratio of subcutaneous small-resistance arteries, whereas ramipril-induced reduction of media to lumen ratio was not statistically significant. No relevant effect on capillary density was observed. In conclusion, treatment with aliskiren or ramipril was associated with a correction of microvascular structural alterations in patients with non–insulin-dependent diabetes mellitus.

Multiple genes of the renin-angiotensin system are novel targets of Wnt/β-catenin signaling

Activation of the renin-angiotensin system (RAS) plays an essential role in the pathogenesis of CKD and cardiovascular disease. However, current anti-RAS therapy only has limited efficacy, partly because of compensatory upregulation of renin expression. Therefore, a treatment strategy to simultaneously target multiple RAS genes is necessary to achieve greater efficacy. By bioinformatics analyses, we discovered that the promoter regions of all RAS genes contained putative T-cell factor (TCF)/lymphoid enhancer factor (LEF)-binding sites, and β-catenin induced the binding of LEF-1 to these sites in kidney tubular cells. Overexpression of either β-catenin or different Wnt ligands induced the expression of all RAS genes. Conversely, a small-molecule β-catenin inhibitor ICG-001 abolished RAS induction. In a mouse model of nephropathy induced by adriamycin, either transient therapy or late administration of ICG-001 abolished established proteinuria and kidney lesions. ICG-001 inhibited renal expression of multiple RAS genes in vivo and abolished the expression of other Wnt/β-catenin target genes. Moreover, ICG-001 therapy restored expression of nephrin, podocin, and Wilms' tumor 1, attenuated interstitial myofibroblast activation, repressed matrix expression, and inhibited renal inflammation and fibrosis. Collectively, these studies identify all RAS genes as novel downstream targets of Wnt/β-catenin. Our results indicate that blockade of Wnt/β-catenin signaling can simultaneously repress multiple RAS genes, thereby leading to the reversal of established proteinuria and kidney injury.

Aliskiren and valsartan mediate left ventricular remodeling post-myocardial infarction in mice through MMP-9 effects

We evaluated whether aliskiren, valsartan, or a combination of both was protective following myocardial infarction (MI) through effects on matrix metalloproteinase (MMP)-9. C57BL/6J wild type (WT, n=94) and MMP-9 null (null, n=85) mice were divided into 4 groups at 3h post-MI: saline (S), aliskiren (A; 50mg/kg/day), valsartan (V; 40mg/kg/day), or A+V and compared to no MI controls at 28days post-MI. All groups had similar infarct areas, and survival rates were higher in the null mice. The treatments influenced systolic function and hypertrophy index, as well as extracellular matrix (ECM) and inflammatory genes in the remote region, indicating that primary effects were on the viable myocardium. Saline treated WT mice showed increased end systolic and diastolic volumes and hypertrophy index, along with reduced ejection fraction. MMP-9 deletion improved LV function post-MI. Aliskiren attenuated the increase in end systolic volume and hypertrophy index, while valsartan improved end diastolic volumes and aliskiren+valsartan improved the hypertrophy index only when MMP-9 was absent. Extracellular matrix and inflammatory gene expression showed distinct patterns among the treatment groups, indicating a divergence in mechanisms of remodeling. This study shows that MMP-9 regulates aliskiren and valsartan effects in mice. These results in mice provide mechanistic insight to help translate these findings to post-MI patients.

Increased aldosterone: mechanism of hypertension in obesity

The prevalence of both obesity and hypertension are increasing worldwide. Hypertension is a common consequence of obesity. Increased central adiposity is associated with increased aldosterone levels and blood pressure in human beings. A number of small studies have shown an association between obesity-mediated hypertension and mechanisms directly linked to increased levels of aldosterone. These studies have shown a trend toward relatively greater blood pressure reduction using aldosterone-receptor blockers compared with other classes of antihypertensive agents. Other than treatment for weight loss, treatment of hypertension with specific antihypertensive medications that block or reduce aldosterone action are appropriate in obese patients. Further research is needed to understand the exact role of the adipocyte in obesity-mediated hypertension.

Anti-stress and nootropic activity of drugs affecting the renin-angiotensin system in rats based on indirect biochemical evidence

INTRODUCTION

Various stress hormones are responsible for bringing out stress-related changes and are implicated in learning and memory processes. The extensive clinical experience of angiotensin receptor blockers (ARBs) and direct renin inhibitor as antihypertensive agents provides anecdotal evidence of improvements in cognition. The neurochemical basis underlying the anti-stress and nootropic effects are unclear. This study was aimed to determine the effects of aliskiren, valsartan and their combination on the neuromediators of the central nervous system (CNS) and periphery as well as on cognitive function.

MATERIALS AND METHODS

Groups of rats were subjected to a forced swim stress for one hour after daily treatment with aliskiren, valsartan and their combination. The 24 h urinary excretion of vanillylmandellic acid (VMA), 5-hydroxyindoleacetic acid (5-HIAA), 6-β-hydroxycortisol (6-β-OH) cortisol and homovanillic acid (HVA) was determined in all groups under normal and stressed conditions. Nootropic activity was studied using cook's pole climbing apparatus and acetylcholinesterase (AChE) inhibitory activity by Ellman's method.

RESULTS

Administration of aliskiren (10 mg/kg), valsartan (20 mg/kg) and their combination at a dose of 5 and 10 mg/kg respectively reduced the urinary metabolite levels. Further, all drugs showed significant improvement in scopolamine-impaired performance and produced inhibition of the AChE enzyme.

CONCLUSIONS

The present study provides scientific support for the anti-stress and nootropic activities of aliskiren, valsartan and their combination.

Aliskiren, the future of renin–angiotensin system blockade?

The suppression of the renin-angiotensin system by angiotensin-converting enzyme inhibitors and angiotensin receptor blockers has been proven in many studies to treat hypertension and reduce cardiovascular events; however, reducing angiotensin I receptor stimulation results in the loss of the negative-feedback signal, leading to increased plasma renin activity. Numerous direct renin inhibitors were synthesized, but abandoned owing to low potency, poor bioavailability and short half-life. Aliskiren, a direct renin inhibitor of a novel structural class, inhibits the activity of the renin produced and, thus, its capacity to form angiotensin I, as measured by plasma renin activity. Aliskiren has been recently shown to be efficacious in hypertensive patients at once-daily oral dosing with favorable pharmacokinetics and the potential to improve end-organ protection.

Endothelial dysfunction in diabetes and hypertension: cross talk in RAS, BMP4, and ROS-dependent COX-2-derived prostanoids

Vascular endothelium regulates cardiovascular function, and endothelial dysfunction is the key initiator for arteriosclerosis and thrombosis and their complications. The endothelium is a dynamic interface that responds to various stimuli and synthesizes and liberates vasoactive molecules such as nitric oxide, prostaglandins, hyperpolarizing factor, and endothelin. Risk factors such as hypertension, hypercholesterolemia, smoking, and hyperglycemia impair the ability of the endothelium to respond to physical or chemical stimulation appropriately, and increased oxidative stress is believed to be a major culprit. This brief article reviews the interplay among several oxidative stress regulators in the vascular wall and highlights therapeutic relevance through deeper understanding of the interplay between the renin-angiotensin system, nicotinamide adenine dinucleotide phosphate, reduced oxidase, bone morphogenic protein 4, and cyclooxygenase 2-derived prostaglandins as a concerted pathogenic cascade in inducing and maintaining endothelial dysfunction in hypertension and diabetes.

Pharmacokinetics, pharmacodynamics, and tolerability of ACT-077825, a new direct renin inhibitor after multiple-ascending doses in healthy subjects

This study was conducted to characterize the multiple-dose tolerability, pharmacokinetics, and pharmacodynamics of ACT-077825, a new direct renin inhibitor, in healthy male subjects. In this single-center, double-blind, placebo-controlled, active-controlled (20 mg of enalapril), randomized multiple-ascending dose study, ACT-077825 was administered once a day. for 7 days in the 50-1000 mg dose range to sodium- and potassium-restricted subjects. ACT-077825 pharmacokinetics on days 1 and 7 were characterized by dose-proportional increases in Cmax and AUCτ. At steady state, accumulation was modest (1.5- to 1.7-fold). Enalapril caused an increase in plasma active renin concentration and plasma renin activity (PRA). ACT-077825 dose dependently increased active renin on days 1 and 7 and inhibited PRA dose dependently only on day 1. On day 7, the maximal PRA inhibition was attained after 250 mg of ACT-077825. In contrast to enalapril, ACT-077825 did not induce any consistent lowering effect on blood pressure when compared with placebo. Of the reported adverse events, diarrhea, headache, and postural dizziness were more frequent. The incidence of diarrhea was greater in the 1000-mg group and a dose of 500 mg of ACT-077825 was identified as the maximum tolerated dose. Overall, pharmacokinetic, pharmacodynamic, and tolerability profiles warrant the further investigation of ACT-077825 in patients with hypertension.

50 years of thiazides: should thiazide diuretics be considered third-line hypertension treatment?

The purpose of this report is to review available and emerging antihypertensive treatment options in light of current guidelines and evidence from large clinical trials. The published literature was reviewed for evidence regarding first-line options for antihypertensive agents, including thiazide-type diuretics, as monotherapy or as part of combination therapy. Current guidelines recommend using thiazide-type diuretics as first-line therapy alone or in combination with another agent. Other commonly used antihypertensive agents include calcium channel blockers, β-adrenergic receptor blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and the direct renin inhibitor, aliskiren. These agents are associated with varying degrees of evidence that they may provide protection from cardiovascular or renal disease beyond that associated with blood pressure reduction. Thiazide diuretics are inexpensive and effective but may not be preferable to other classes of antihypertensives that reduce blood pressure to a similar extent with a better safety profile and superior reductions in cardiovascular event rates. However, calcium channel blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and direct renin inhibitors also show promise as initial monotherapy or as part of a combination therapy regimen. In patients requiring additional blood pressure reduction, add-on therapy with a diuretic could provide additional blood pressure-lowering efficacy.

Renoprotective effects of the direct renin inhibitor aliskiren on gentamicin-induced nephrotoxicity in rats

This study aimed to examine the protective effects of aliskiren on gentamicin-induced nephropathy. Rats were injected with gentamicin (100 mg/kg per day) for 14 days. Aliskiren was infused for two weeks. Human proximal tubular epithelial cell lines (HK-2) were cultured with gentamicin in the absence or presence of aliskiren. Inflammatory profibrotic and apoptotic markers were evaluated in vivo and in vitro. Aliskiren treatment attenuated the decreased creatinine clearance, increased fractional sodium excretion, glomerulosclerosis and tubulointerstitial fibrosis and counteracted the increased ED-1 expression in gentamicin-treated rats. The levels of inflammatory cytokines (TNF-α, IL-1β and IFN-γ) and adhesion molecules (MCP-1, ICAM-1 and VCAM-1) increased in the gentamicin-treated kidneys. These changes were restored by aliskiren co-treatment. Aliskiren effectively reversed transforming growth factor-β-induced fibrotic responses such as induction of α-smooth muscle actin in gentamicin-treated rat kidneys. Along with these changes, aliskiren also attenuated the increase in nuclear factor κB and phosphorylated extracellular signal-regulated kinase (pERK 1/2) levels in HK-2 cells cultured with gentamicin. In addition, aliskiren decreased the number of TUNEL-positive nuclei and reduced the expression of proapoptotic markers in gentamicin-treated HK-2 cells. These findings suggest that aliskiren attenuates gentamicin-induced nephropathy by suppression of inflammatory, profibrotic and apoptotic factors through inhibition of the nuclear factor κB, Smads and mitogen-activated protein kinase signaling pathways.

Effectiveness and safety of aliskiren and aliskiren hydrochlorothiazide (HCT) in a multiethnic, real-world setting

INTRODUCTION

Numerous randomized clinical trials have demonstrated the efficacy and tolerability of aliskiren and aliskiren hydrochlorothiazide (aliskiren HCT) single-pill combination therapy in patients with hypertension. The objective of the present study was to evaluate the effectiveness and safety of aliskiren-based therapy under daily life conditions in a multiethnic population.

METHODS

This observational, multicenter, noninterventional study, conducted at 420 centers in Asia and the Middle East, included adult patients with hypertension who received treatment with aliskiren or aliskiren HCT as single or add-on therapy for a planned treatment period of at least 26 weeks. The main effectiveness assessments included the proportion of patients achieving therapeutic blood pressure (BP) goal (defined as systolic BP [SBP]/diastolic BP [DBP]<140/90 mmHg, or <130/80 mmHg in patients with diabetes) and BP response, and change in mean sitting BP from baseline to study end.

RESULTS

Of 4,826 patients (mean age 51.4 years, 65.9% male, 64.5% Asian, 41.5% diabetic) included in the study, 3,473 received aliskiren and 1,353 received aliskiren HCT. Almost half the study population (48.1%) received aliskiren or aliskiren HCT as add-on therapy. The therapeutic BP goal was achieved in 49.5% of patients treated with aliskiren and 48.3% of patients receiving aliskiren HCT; attainment of BP goal increased to more than 70% when a classic BP target of <140/90 mmHg was applied for all patients. Reductions in mean sitting SBP/DBP were significantly lower versus baseline for both aliskiren (24.1/12.2 mmHg) and aliskiren HCT (27.6/14.1 mmHg) and BP response rates were consistently achieved in more than 80% of all patients during the study. Aliskiren treatment was well tolerated with only a small proportion of patients experiencing adverse events (AEs; 2.1%) and serious AEs (0.3%).

CONCLUSION

In this real-world, naturalistic setting, antihypertensive treatment with an aliskiren-based regimen was effective and well-tolerated in this multiethnic population with arterial hypertension.

Renin inhibition in the treatment of diabetic kidney disease

Inhibition of the RAAS (renin–angiotensin–aldosterone system) plays a pivotal role in the prevention and treatment of diabetic nephropathy and a spectrum of other proteinuric kidney diseases. Despite documented beneficial effects of RAAS inhibitors in diabetic patients with nephropathy, reversal of the progressive course of this disorder or at least long-term stabilization of renal function are often difficult to achieve, and many patients still progress to end-stage renal disease. Incomplete inhibition of the RAAS has been postulated as one of reasons for unsatisfactory therapeutic responses to RAAS inhibition in some patients. Inhibition of renin, a rate-limiting step in the RAAS activation cascade, could overcome at least some of the abovementioned problems associated with the treatment with traditional RAAS inhibitors. The present review focuses on experimental and clinical studies evaluating the two principal approaches to renin inhibition, namely direct renin inhibition with aliskiren and inhibition of the (pro)renin receptor. Moreover, the possibilities of renin inhibition and nephroprotection by interventions primarily aiming at non-RAAS targets, such as vitamin D, urocortins or inhibition of the succinate receptor GPR91 and cyclo-oxygenase-2, are also discussed.

Maternal caffeine administration leads to adverse effects on adult mice offspring

PURPOSE

This study aimed to evaluate the role of caffeine chronic administration during gestation of C57BL/6 mice on cardiac remodeling and the expression of components of the renin-angiotensin system (RAS) in male offspring as adults.

METHODS

Pregnant C57BL/6 female mice were divided into two groups (n = 10): Control group (C), dams were injected with the vehicle only (saline 0.9% NaCl); Caffeine group (CF), dams received daily a subcutaneous injection of 20 mg/kg of caffeine/day (1 mg/mL saline). Pups had free access to standard chow since weaning to 3 months of age, when they were killed.

RESULTS

CF group showed increased energy expenditure (+7%) with consequent reduction in body mass (BM) gain (-18%), increased blood pressure (+48%), and higher heart rate (+10%) than C group. The ratio between LV mass/BM was greater (+10%), with bigger cardiomyocytes (+40%), and reduced vascularization (-25%) in CF group than in C group. In the LV, the expression of angiotensin-converting enzyme (+30%), Angiotensin II (AngII) (+60%), AngII receptor (ATR)-1 (+77%) were higher, and the expression of ATR-2 was lower (-46%; P < 0.05) in CF group than in C group. In the kidney, the expressions of renin (+128%) and ATR-1 (+88%) were higher in CF group than in C group.

CONCLUSIONS

Chronic administration of caffeine to pregnant dams led to persistent activation of local RAS in the kidney and heart of the offspring, which, in turn, leads to high BP and adverse cardiac remodeling. These findings highlight the urge to encourage pregnant women to avoid food or medicines containing caffeine.

Antiproteinuric effect of add-on paricalcitol in CKD patients under maximal tolerated inhibition of renin-angiotensin system: a prospective observational study

Background

Whether paricalcitol (PCT) reduces proteinuria in the presence of intensified inhibition of Renin-Angiotensin-System (RAS) is poorly studied. We evaluated the antiproteinuric effect of PCT in non-dialysis chronic kidney disease (CKD) patients with proteinuria greater than 0.5 g/24 h persisting despite anti-RAS therapy titrated to minimize proteinuria in the absence of adverse effects.

Methods

Forty-eight CKD patients were studied in the first six months of add-on oral PCT (1 mcg/day) and three months after drug withdrawal.

Results

Males were 87.5%, age 63 ± 14 yrs, systolic/diastolic blood pressure (BP) 143 ± 22/78 ± 11 mmHg, eGFR 29.7 ± 14.5 mL/min/1.73 m², diabetes 40%, and cardiovascular disease 38%. At referral in the center (28 months prior to study baseline), proteinuria was 2.44 (95% CI 1.80-3.04) g/24 h with 6 patients not receiving any anti-RAS and 42 treated with a single agent, at low dosage in most cases. At study baseline, twenty patients were under 2–3 anti-RAS drugs while twenty-eight received 1 agent at full dose and proteinuria resulted to be reduced versus referral to 1.23 g/24 h (95%CI 1.00-1.51). Six months of add-on PCT significantly decreased proteinuria to 0.61 g/24 h (95%CI 0.40-0.93), with levels less than 0.5 g/24 h achieved in 37.5% patients, in the absence of changes of BP and GFR. Proteinuria recovered to basal value after drug withdrawal. The extent of antiproteinuric response to PCT was positively associated with diabetes, eGFR and daily Na excretion (R² = 0.459, P < 0.0001). PTH decreased from 201 (IQR 92–273) to 83 (IQR 50–189) pg/mL.

Conclusions

In CKD patients, add-on PCT induces a significant reduction of proteinuria that is evident despite intensified anti-RAS therapy and larger in the presence of diabetes, higher GFR and unrestricted salt intake.

A low-dose combination of valsartan and low molecular weight heparin better improved glomerular permeability than did high-dose monotherapy in rats with diabetic nephropathy

Diabetic nephropathy is the most common and severe renal complication of diabetes mellitus. The present study sought to investigate the renoprotective effects of a combination therapy of valsartan and low molecular weight heparin (LMWH) in rats with diabetic nephropathy induced by uninephrectomy and streptozotocin. The animals were divided into five groups as follows: sham-operated rats, diabetic control rats, diabetic rats treated with 20 mg/kg/day valsartan, diabetic rats treated with 600 IU/kg/day LMWH, diabetic rats treated with a combination of valsartan and LMWH (valsartan 10 mg/kg/day and LMWH 300 IU/kg/day). The treatment regimen was maintained for 8 weeks. Treatment with valsartan, LMWH, or a combination of the two had no significant effect on blood glucose levels. However, the urine protein excretion levels significantly decreased for the three drug treatment groups; the most dramatic decreases were observed in the combination treatment group. Kidney histology was examined using periodic acid-Schiff staining and immunohistochemical staining of extracellular matrix proteins. Results indicated that histopathology improved markedly in the three drug treatment groups; combination therapy had an equal or better effect than monotherapy in terms of decreasing the abnormal thickness of the glomerular basal membrane, the ratio of the area of the mesangial region with respect to the total area of renal glomeruli, and the accumulation of collagen IV and laminin in kidney tissue. In addition, serum levels of transforming growth factor-β1 (TGF-β1) also markedly decreased in the drug treatment groups according to ELISA. However, there were no significant differences between the combination therapy group and monotherapy group. These results suggest that a combination of valsartan and LMWH at half the dose used in monotherapy is better at improving glomerular permeability in rats with diabetic nephropathy.

A comparison of the antihypertensive and anti-inflammatory effects of aliskiren and ramipril add-on therapy in peritoneal dialysis patients--a pilot open label study

Most hypertensive dialysis patients are currently treated with angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB). Aliskiren, the direct renin inhibitor, has not been specifically studied in peritoneal dialysis patients. The aim of the study was to compare hypotensive effects of aliskiren and ramipril and their influence on serum potassium and inflammatory parameters in hypertensive peritoneal dialysis patients. Eighteen hypertensive patients on chronic peritoneal dialysis were enrolled in an open-label comparative fixed-order study. The patients had been off RAAS blocking drugs for ≥4 weeks prior to an inclusion. At each of 3 study visits (baseline and after each of the treatment periods) blood pressure, serum lipids, potassium, renin, aldosterone, C-reactive protein (CRP) and monocyte chemotactic protein-1 (MCP-1) were measured. After the baseline visit aliskiren was started (150 mg/d) and after 12 weeks replaced with ramipril (5 mg/d) for the next 12 weeks. Blood pressure was 142/88±15/11 mmHg at baseline, 137/84±10/8 mmHg after aliskiren (ns) and 126/81±11/7 mmHg after ramipril (p<0.05 vs baseline and aliskiren). No incidents of hyperkalemia were observed. Plasma renin concentration increased significantly during aliskiren treatment compared to ramipril (227,6±844 vs. 58,3±765 pg/mL). CRP was similar after both therapies (8,8±34 vs. 8,4±32 µg/mL) but MCP-1 concentration was significantly lower after aliskiren than after ramipril (294,0±172,6 vs. 358,9±183,3 pg/mL). Aliskiren 150 mg/day decreases blood pressure less effectively than ramipril 5 mg/day in peritoneal dialysis patients. It does not influence serum potassium. The decrease of MCP-1 concentration after aliskiren treatment may provide an indirect evidence for its blood pressure independent cardioprotective and anti-inflammatory effects.

Disruption of muscle renin-angiotensin system in AT1a-/- mice enhances muscle function despite reducing muscle mass but compromises repair after injury

The role of the renin-angiotensin system (RAS) in vasoregulation is well established, but a localized RAS exists in multiple tissues and exerts diverse functions including autonomic control and thermogenesis. The role of the RAS in the maintenance and function of skeletal muscle is not well understood, especially the role of angiotensin peptides, which appear to contribute to muscle atrophy. We tested the hypothesis that mice lacking the angiotensin type 1A receptor (AT(1A)(-/-)) would exhibit enhanced whole body and skeletal muscle function and improved regeneration after severe injury. Despite 18- to 20-wk-old AT(1A)(-/-) mice exhibiting reduced muscle mass compared with controls (P < 0.05), the tibialis anterior (TA) muscles produced a 25% higher maximum specific (normalized) force (P < 0.05). Average fiber cross-sectional area (CSA) and fiber oxidative capacity was not different between groups, but TA muscles from AT(1A)(-/-) mice had a reduced number of muscle fibers as well as a higher proportion of type IIx/b fibers and a lower proportion of type IIa fibers (P < 0.05). Measures of whole body function (grip strength, rotarod performance, locomotor activity) were all improved in AT(1A)(-/-) mice (P < 0.05). Surprisingly, the recovery of muscle mass and fiber CSA following myotoxic injury was impaired in AT(1A)(-/-) mice, in part by impaired myoblast fusion, prolonged collagen infiltration and inflammation, and delayed expression of myogenic regulatory factors. The findings support the therapeutic potential of RAS inhibition for enhancing whole body and skeletal muscle function, but they also reveal the importance of RAS signaling in the maintenance of muscle mass and for normal fiber repair after injury.

Aliskiren prevents the toxic effects of peritoneal dialysis fluids during chronic dialysis in rats

The benefits of long-term peritoneal dialysis (PD) in patients with end-stage renal failure are short-lived due to structural and functional changes in the peritoneal membrane. In this report, we provide evidence for the in vitro and in vivo participation of the renin-angiotensin-aldosterone system (RAAS) in the signaling pathway leading to peritoneal fibrosis during PD. Exposure to high-glucose PD fluids (PDFs) increases damage and fibrosis markers in both isolated rat peritoneal mesothelial cells and in the peritoneum of rats after chronic dialysis. In both cases, the addition of the RAAS inhibitor aliskiren markedly improved damage and fibrosis markers, and prevented functional modifications in the peritoneal transport, as measured by the peritoneal equilibrium test. These data suggest that inhibition of the RAAS may be a novel way to improve the efficacy of PD by preventing inflammation and fibrosis following peritoneal exposure to high-glucose PDFs.

Molecular mechanism of vitamin D in the cardiovascular system

Vitamin D deficiency is a global health problem that has various adverse consequences. Vitamin D is mainly synthesized in the skin by sunlight (UV light) irradiation; therefore, vitamin D status is influenced by geographic locations, seasonal changes, and skin pigmentations. The kidney is involved in the biosynthesis of 1,25-dihydroxyvitamin D and the reuptake of filtered 25-hydroxyvitamin D from the proximal tubules, thus, vitamin D deficiency is highly prevalent in patients with kidney disease who have renal insufficiency. There is a growing body of epidemiological and clinical evidence in the literature that links vitamin D deficiency to cardiovascular disease. The discovery of the vitamin D hormone functioning as an endocrine inhibitor of the renin-angiotensin system provides an explanation for this association. This review will discuss the mechanism underlying the connection between vitamin D and cardiovascular disease and its physiological and therapeutic implications.

Aliskiren for the treatment of essential hypertension under real-life practice conditions: design and baseline data of the prospective 3A registry

BACKGROUND

The renin-angiotensin system (RAS) is a key target for blood pressure control and for cardiovascular and renal protection. Aliskiren is the first-in-class direct oral inhibitor of renin that controls the rate-limiting step in the RAS cascade. So far little is known about the use and efficacy of aliskiren in the treatment of essential hypertension under clinical practice conditions.

METHODS

The 3A registry was an open, prospective cohort study (observational registry) of 14,988 patients in 899 offices throughout Germany. Consecutive patients were eligible for inclusion if their physician had decided to modify their antihypertensive therapy. This included treatment with aliskiren or an angiotensin converting enzyme inhibitor (ACE-I)/angiotensin receptor blocker (ARB) or agents not blocking the RAS, alone or on top of an existing drug regimen.

RESULTS

Mean age of patients was 65 years, their mean body mass index was 28.2 kg/m(2) 53.5% were men, 36% working, 90% in statutory health insurance and 26% in any disease management programme. Patients in the aliskiren and the RAS groups compared with the non-RAS group were older, more often men, had a longer history of hypertension, and had a higher prevalence of comorbidities (diabetes, chronic heart failure, ischaemic heart disease, renal disease). Mean systolic, but not diastolic blood pressure was substantially higher in the aliskiren group (158/91 mmHg vs. 154/89 mmHg in ACE-I/ARB vs. 152/89 mmHg in non-RAS). Mean number of antihypertensive drugs was higher in the aliskiren group compared with the other groups (3.0 drugs vs. 2.5 in ACE-I/ARB vs. 1.6 in non-RAS; p < 0.0001).

CONCLUSIONS

In this large cohort of outpatients with hypertension, aliskiren was used mainly in patients with more severe stages of hypertension and those with concomitant diseases such as diabetes mellitus and impaired renal function. The 3A registry will provide important information about the use and efficacy of aliskiren in a real-life setting.