Effect of inhibitors of the renin-angiotensin system and other antihypertensive drugs on renal outcomes: systematic review and meta-analysis

What is next when the first blood pressure-lowering drug is not sufficient?

A large proportion of patients with hypertension require a second blood pressure-lowering drug to reach blood pressure control. None of the major clinical trials of blood pressure drugs have compared, in a random fashion, the efficacy of the second drug in the prevention of hard outcomes and only one large observational study has evaluated the link between different associations of drugs and the incidence of cardiovascular disease. There are a few well-designed clinical trials comparing the blood pressure-lowering effect of drugs added with the first option. Therefore, choosing the second option is largely empirical and still not based on the best standards of evidence-based medicine, resulting in vague recommendations from guidelines. A large NIH-sponsored trial comparing the second choice in patients already on diuretics has been planned. For now, in the absence of a sound basis for choosing the second blood pressure-lowering agent, the classical stepped-care approach recommended by the first National High Blood Pressure Education Program may still be a valid guideline.

Antihypertensive treatment and renal protection: the role of drugs inhibiting the renin-angiotensin-aldosterone system

The prevalence of chronic kidney disease, currently estimated to vary between 8 and 12 % in the general population, is steadily rising due to aging and to the ongoing epidemic of hypertension and type 2 diabetes. Even in its early stages, chronic kidney disease entails a greater risk for cardiovascular mortality, and its prevention and treatment is rapidly becoming a key medical issue for many health care systems worldwide. Adequate blood pressure control and reduction of urine protein excretion, preferably obtained by the use of renin-angiotensin-aldosterone system inhibitors, have traditionally been considered the mainstay of therapeutic strategies in patients with renal disease. Given the pivotal role of renin-angiotensin-aldosterone system activity in the pathogenesis and progression of renal and cardiovascular damage, a more profound inhibition of the system, either by the use of multiple agents or by a single agent at high dosage has recently been advocated, especially in the presence of proteinuria. Recent trials, however have failed to confirm the usefulness of this therapeutic approach, at least in unselected patients. This article will critically review the current literature and will discuss the clinical implications of targeting the renin-angiotensin-aldosterone system in order to provide the greatest renal protection.

Dialysis-associated hypertension treated with Telmisartan--DiaTel: a pilot, placebo-controlled, cross-over, randomized trial

Treatment of hypertension in hemodialysis (HD) patients is characterised by lack of evidence for both the blood pressure (BP) target goal and the recommended drug class to use. Telmisartan, an Angiotensin receptor blocker (ARB) that is metabolised in the liver and not excreted via HD extracorporeal circuit might be particularly suitable for HD patients. We designed and conducted a randomised, placebo-controlled, double-blind and cross-over trial for treatment of dialysis-associated hypertension with telmisartan 80 mg once daily or placebo on top of standard antihypertensive treatment excluding other Renin-Angiotensin-System (RAS) blockers. In 29 patients after randomization we analysed BP after a treatment period of 8 weeks, while 13 started with telmisartan and 16 with placebo; after 8 weeks 11 continued with telmisartan and 12 with placebo after cross-over, respectively. Patients exhibited a significant reduction of systolic pre-HD BP from 141.9±21.8 before to 131.3±17.3 mmHg after the first treatment period with telmisartan or placebo. However, no average significant influence of telmisartan was observed compared to placebo. The latter may be due to a large inter-individual variability of BP responses reaching from a 40 mmHg decrease under placebo to 40 mmHg increase under telmisartan. Antihypertensive co-medication was changed for clinical reasons in 7 out of 21 patients with no significant difference between telmisartan and placebo groups. Our starting hypothesis, that telmisartan on top of standard therapy lowers systolic office BP in HD patients could not be confirmed. In conclusion, this small trial indicates that testing antihypertensive drug efficacy in HD patients is challenging due to complicated standardization of concomitant medication and other confounding factors, e.g. volume status, salt load and neurohormonal activation, that influence BP control in HD patients.

TRIAL REGISTRATION

Clinicaltrialsregister.eu 2005-005021-60.

Predictors of the incidence of all-cause mortality and deaths due to diabetes and renal diseases among patients newly prescribed antihypertensive agents: a cohort study

BACKGROUND

Randomized trials have shown that the major antihypertensive drug classes are similarly effective to reduce mortality, but whether these drug class difference exists in clinical practice has been scarcely explored. This study evaluated the association between antihypertensive drug class, all-cause mortality and deaths due to diabetes or renal disease in real-life clinical settings.

METHODS

A clinical database in Hong Kong included all patients who were prescribed their first-ever antihypertensive agents between 2001 and 2005 from the public healthcare sector. All patients were followed up for five years, and grouped according to the initial antihypertensive prescription. The associations between antihypertensive drug class, all-cause mortality or combined diabetes and renal mortality, respectively, were evaluated by Cox proportional hazard models.

RESULTS

From 218,047 eligible patients, 33,288 (15.3%) died within five years after their first-ever antihypertensive prescription and among which 1055 patients (0.48%) died of diabetes or renal disease. After adjusted for age, gender, socioeconomic status, service settings, district of residence, medication adherence, and the number of comorbidities, each drug class was similarly likely to be associated with mortality due to diabetes or renal disease [Adjusted Hazard Ratios (AHR) ranged from 0.92 to 1.73, p=0.287-0.939] and all-cause mortality (AHR ranged from 0.83 to 1.02) except for beta-blockers (AHR=0.815, 95% C.I. 0.68-0.87, p=0.024) when ACEI was used as a reference group in propensity score-adjusted analysis.

CONCLUSIONS

These findings provide real-life evidence reinforcing that any major antihypertensive drug class is suitable as a first-line agent for management of hypertension as recommended by international guidelines.

ELISA examining urinary angiotensinogen as a potential indicator of intrarenal renin-angiotensin system (RAS) activity: a clinical study of 128 chronic kidney disease patients

In the current study, we measured urinary angiotensinogen (AGT) through enzyme-linked immunoadsordent assay (ELISA) and analyzed its correlation with intrarenal renin-angiotensin system (RAS) activity in 128 chronic kidney disease (CKD) patients. Urinary and plasma renin activity, AGT, angiotensin II (Ang II) and aldosterone levels were also measured by radioimmunoassay (RIA) or ELISA in these participants. Further, the expression level of intrarenal renin, AGT, Ang II and Ang II receptors were examined by immunohistochemistry staining (IHCS) in 72 CKD patients. Their correlations with urinary AGT were also analyzed. We found that the urinary AGT level was positively correlated with hypertension (ρ = 0.28, P < 0.01), urinary protein (r = 0.38, P < 0.01), urinary Ang II (r = 0.29, P < 0.05), urinary type IV collagen (Col IV) (r = 0.56, P < 0.01), and was negatively correlated with estimated glomerular filtration rate (eGFR) (r = -0.28, P < 0.01), urinary sodium (r = -0.22, P < 0.05) and serum AGT (r = -0.27, P < 0.01). Multiple regression analysis indicated low serum AGT (P < 0.01), high urinary protein (P < 0.01), high urinary Ang II (P < 0.05) and high urinary Col IV (P < 0.01) were correlated significantly with high urinary AGT. Urinary AGT level was positively correlated with intrarenal expression level of AGT (ρ = 0.46, P < 0.01), Ang II (ρ = 0.56, P < 0.01) and Ang II type 1 receptor (ρ = 0.32, P < 0.01), as detected by IHCS. Together, these data suggest that urinary AGT might be a potential biomarker of intrarenal RAS and Ang II activities in CKD patients.

Aggressive blood pressure reduction and renin-angiotensin system blockade in chronic kidney disease: time for re-evaluation?

Over the past decades, aggressive control of blood pressure (BP) and blockade of the renin-angiotensin-aldosterone system (RAAS) were considered the cornerstones of treatment against progression of chronic kidney disease (CKD), following important background and clinical evidence on the associations of hypertension and RAAS activation with renal injury. To this end, previous recommendations included a BP target of <130/80 mm Hg for all individuals with CKD (and possibly <125/75 mm Hg for those with proteinuria >1 g/day), as well as use of angiotensin-converting-enzyme inhibitors and angiotensin receptor blockers as first-line therapy for hypertension in all CKD patients. However, long-term extensions of relevant clinical trials support a low-BP goal only for patients with proteinuria, whereas recent cardiovascular trials questioned the benefits of low systolic BP for diabetic patients, leading to more individualized recommendations. Furthermore, our previous knowledge of the specific renoprotective properties of RAAS blockers in patients with proteinuric CKD is now extended with data on the use of these agents in patients with less advanced nephropathy and/or absence of proteinuria, deriving mostly from subanalyses of cardiovascular trials. This review discusses previous and recent clinical evidence on the issues of BP reduction and RAAS blockade by type and stage of renal damage, aiming to aid clinicians in their treatment decisions for patients with CKD.

Hypertensive target organ damage and the risk for vascular events and all-cause mortality in patients with vascular disease

OBJECTIVE

Presence of hypertensive target organ damage is related to increased vascular risk and mortality. Whether combined presence of hypertensive target organ damage confers higher vascular risk compared to single presence is unknown. This study evaluates the separate and combined effects of impaired renal function [estimated glomerular filtration rate (eGFR) ≤60 ml/min per 1.73 m], albuminuria (albumin/creatinine-ratio men ≥2.5 mg/mmol, women ≥3.5 mg/mmol) and left-ventricular hypertrophy (LVH) (Sokolow-Lyon and/or Cornell-voltage criterion) on the occurrence of vascular events and mortality in patients with vascular disease (coronary artery disease, cerebrovascular disease, and peripheral arterial disease).

METHODS AND RESULTS

A cohort of patients with vascular diseases (n = 4319) was followed (median 4.4 years) for the occurrence of vascular events (stroke, myocardial infarction, vascular death) and mortality. LVH was present in 11%, impaired renal function in 15%, and albuminuria in 18%. Presence of at least two hypertensive target organ damage was prevalent in 8%. The risk for vascular events was hazard ratio 1.5 [95% confidence interval (CI) 1.2-1.9] for presence of one hypertensive target organ damage and hazard ratio 3.8 (95% CI 2.3-6.3) for three manifestations of hypertensive target organ damage (adjusted for age, sex). For mortality this was hazard ratio 1.4 (95% CI 1.1-1.7) and hazard ratio 3.2 (95% CI 1.9-5.2). Hazard ratios for single presence of different types of organ damage were comparable and independent of the presence of hypertension.

CONCLUSIONS

Impaired renal function, albuminuria, and LVH are prevalent in patients with vascular disease and confer independent and additive risk for vascular events and mortality. Measurement of hypertensive target organ damage in patients with vascular disease identifies patients at very high risk and may have treatment implications.

Active vitamin D treatment for reduction of residual proteinuria: a systematic review

Despite renin-angiotensin-aldosterone system blockade, which retards progression of CKD by reducing proteinuria, many patients with CKD have residual proteinuria, an independent risk factor for disease progression. We aimed to address whether active vitamin D analogs reduce residual proteinuria. We systematically searched for trials published between 1950 and September of 2012 in the Medline, Embase, and Cochrane Library databases. All randomized controlled trials of vitamin D analogs in patients with CKD that reported an effect on proteinuria with sample size≥50 were selected. Mean differences of proteinuria change over time and odds ratios for reaching ≥15% proteinuria decrease from baseline to last measurement were synthesized under a random effects model. From 907 citations retrieved, six studies (four studies with paricalcitol and two studies with calcitriol) providing data for 688 patients were included in the meta-analysis. Most patients (84%) used an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker throughout the study. Active vitamin D analogs reduced proteinuria (weighted mean difference from baseline to last measurement was -16% [95% CI, -13% to -18%]) compared with controls (+6% [95% CI, 0% to +12%]; P<0.001). Proteinuria reduction was achieved more commonly in patients treated with an active vitamin D analog (204/390 patients) than control patients (86/298 patients; OR, 2.72 [95% CI, 1.82 to 4.07]; P<0.001). Thus, active vitamin D analogs may further reduce proteinuria in CKD patients in addition to current regimens. Future studies should address whether vitamin D therapy also retards progressive renal functional decline.

Visit-to-visit blood pressure variability is related to albuminuria variability and progression in patients with type 2 diabetes

Recent studies have suggested that visit-to-visit variability of blood pressure (BP) is correlated with microalbuminuria in patients with diabetes, independent of mean pressure. We investigated the contribution of BP variability to albuminuria progression in normoalbuminuric type 2 diabetes patients. BP and urinary albumin excretion of patients were assessed in each visit during a median follow-up of 31 months. Variability was assessed using standard deviation, coefficient of variation, standard deviation independent of mean, peak, average real variability, and average real variability independent of mean. Of 194 patients enrolled, 31 subjects (16.0%) developed microalbuminuria. Systolic blood pressure (SBP) variability indices (except for coefficient of variation and average real variability) were significant predictors of microalbuminuria in multivariate Cox regression models (hazard ratio ranging from 2.02 to 2.76). The same was not observed for diastolic blood pressure. Using linear regression, SBP variability significantly correlated with some but not all indices of albuminuria variability. Peak SBP was the strongest predictor of albuminuria variability in multivariate models (standardized beta ranging from 0.216 to 0.339). In conclusion, visit-to-visit variability of SBP is an independent risk factor for development of microalbuminuria in patients with diabetes, and is associated with an increased variability in albuminuria.

Beneficial effects of the activation of the angiotensin-(1-7) MAS receptor in a murine model of adriamycin-induced nephropathy

Angiotensin-(1–7) [Ang-(1–7)] is a biologically active heptapeptide that may counterbalance the physiological actions of angiotensin II (Ang II) within the renin-angiotensin system (RAS). Here, we evaluated whether activation of the Mas receptor with the oral agonist, AVE 0991, would have renoprotective effects in a model of adriamycin (ADR)-induced nephropathy. We also evaluated whether the Mas receptor contributed for the protective effects of treatment with AT₁ receptor blockers. ADR (10 mg/kg) induced significant renal injury and dysfunction that was maximal at day 14 after injection. Treatment with the Mas receptor agonist AVE 0991 improved renal function parameters, reduced urinary protein loss and attenuated histological changes. Renoprotection was associated with reduction in urinary levels of TGF-β. Similar renoprotection was observed after treatment with the AT₁ receptor antagonist, Losartan. AT₁ and Mas receptor mRNA levels dropped after ADR administration and treatment with losartan reestablished the expression of Mas receptor and increased the expression of ACE2. ADR-induced nephropathy was similar in wild type (Mas^+/+) and Mas knockout (Mas^−/−) mice, suggesting there was no endogenous role for Mas receptor activation. However, treatment with Losartan was able to reduce renal injury only in Mas^+/+, but not in Mas^−/− mice. Therefore, these findings suggest that exogenous activation of the Mas receptor protects from ADR-induced nephropathy and contributes to the beneficial effects of AT₁ receptor blockade. Medications which target specifically the ACE2/Ang-(1–7)/Mas axis may offer new therapeutic opportunities to treat human nephropathies.

Effects of a new SGLT2 inhibitor, luseogliflozin, on diabetic nephropathy in T2DN rats

This study examined the effect of long-term control of hyperglycemia with a new sodium glucose cotransporter 2 inhibitor, luseogliflozin, given alone or in combination with lisinopril on the progression of renal injury in the T2DN rat model of type 2 diabetic nephropathy. Chronic treatment with luseogliflozin (10 mg/kg/day) produced a sustained increase in glucose excretion and normalized blood glucose and glycosylated hemoglobin levels to the same level as seen in the rats treated with insulin. It had no effect on blood pressure. In contrast, lisinopril (10 mg/kg/day) reduced mean blood pressure from 140 to 113 mmHg. Combination therapy significantly reduced blood pressure more than that seen in the rats treated with lisinopril. T2DN rats treated with vehicle exhibited progressive proteinuria, a decline in glomerular filtration rate (GFR), focal glomerulosclerosis, renal fibrosis, and tubular necrosis. Control of hyperglycemia with luseogliflozin prevented the fall in GFR and reduced the degree of glomerular injury, renal fibrosis, and tubular necrosis. In contrast, control of hyperglycemia with insulin had no effect on the progression of renal disease in T2DN rats. Reducing blood pressure with lisinopril prevented the fall in GFR and reduced proteinuria and the degree of glomerular injury and tubular necrosis. Combination therapy reduced the degree of glomerular injury, renal fibrosis, and tubular necrosis to a greater extent than administration of either drug alone. These results suggest that control of hyperglycemia with luseogliflozin slows the progression of diabetic nephropathy more than that seen with insulin, and combination therapy is more renoprotective than administration of either compound alone.

The effects of preoperative renin-angiotensin system inhibitors on outcomes in patients undergoing cardiac surgery

OBJECTIVE

The effects of preoperative (pre-op) renin-angiotensin system (RAS) inhibitors on outcomes in patients undergoing cardiac surgery remain uncertain. The aim of this study was to evaluate whether the use of pre-op RAS inhibitors affected major outcomes of cardiac surgery.

DESIGN

A retrospective cohort study.

SETTING

A university teaching hospital.

PARTICIPANTS

Patients undergoing cardiac surgery between January 1, 2001 and December 31, 2011.

INTERVENTIONS

One thousand two hundred thirty-nine patients who received pre-op RAS inhibitors were compared with those who did not (control group, n = 1,083).

MEASUREMENTS AND MAIN RESULTS

Acute kidney injury (AKI) was defined using Acute Kidney Injury Network classification. Patients in the RAS inhibitors group presented with higher comorbidities. Pre-op RAS inhibitors therapy was associated with the reduction in the incidence of AKI (27.2% v 34.0%, p<0.001), septicemia (1.9% v 3.5%, p = 0.019), and operative mortality (2.99% v 4.62%, p = 0.039). After adjusted propensity scores and multivariate logistic regression, the pre-op RAS inhibitors were found to have protective effects against AKI (odds ratio [OR]: 0.764, 95% confidence interval [CI]: 0.670-0.873, p<0.001), septicemia (OR: 0.515, 95% CI: 0.348-0.761, p>0.001), and operative mortality (OR: 0.539, 95% CI: 0.348-0.758, p<0.001).

CONCLUSION

The results suggested that pre-op RAS inhibitor therapy was associated with significant reductions in the risk of AKI, operative mortality, and septicemia.

The natural history of, and risk factors for, progressive chronic kidney disease (CKD): the Renal Impairment in Secondary care (RIISC) study; rationale and protocol

BACKGROUND

Chronic kidney disease (CKD) affects up to 16% of the adult population and is associated with significant morbidity and mortality. People at highest risk from progressive CKD are defined by a sustained decline in estimated glomerular filtration rate (eGFR) and/or the presence of significant albuminuria/proteinuria and/or more advanced CKD. Accurate mapping of the bio-clinical determinants of this group will enable improved risk stratification and direct the development of better targeted management for people with CKD.

METHODS/DESIGN

The Renal Impairment In Secondary Care study is a prospective, observational cohort study, patients with CKD 4 and 5 or CKD 3 and either accelerated progression and/or proteinuria who are managed in secondary care are eligible to participate. Participants undergo a detailed bio-clinical assessment that includes measures of vascular health, periodontal health, quality of life and socio-economic status, clinical assessment and collection of samples for biomarker analysis. The assessments take place at baseline, and at six, 18, 36, 60 and 120 months; the outcomes of interest include cardiovascular events, progression to end stage kidney disease and death.

DISCUSSION

The determinants of progression of chronic kidney disease are not fully understood though there are a number of proposed risk factors for progression (both traditional and novel). This study will provide a detailed bio-clinical phenotype of patients with high-risk chronic kidney disease (high risk of both progression and cardiovascular events) and will repeatedly assess them over a prolonged follow up period. Recruitment commenced in Autumn 2010 and will provide many outputs that will add to the evidence base for progressive chronic kidney disease.

Endothelial nitric oxide synthase gene polymorphisms and renal responsiveness to RAS inhibition therapy in type 2 diabetic Asian Indians

AIM

To investigate the association of functional single nucleotide polymorphisms (SNPs) of the endothelial nitric oxide synthase gene (eNOS) gene (T-786C, G894T) and one variable number tandem repeat polymorphism (aa 27VNTR bb) with reno-protective response to angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) therapy in North Indian type 2 diabetic mellitus (T2DM) subjects with cases having diabetic nephropathy (DN) and controls without DN.

METHOD

We genotyped three polymorphisms of eNOS (two SNPs: T-786C, G894T and one 27 VNTR) in T2DM patients with overt nephropathy (cases: n=320) and T2DM patients without overt nephropathy (controls: n=490), using validated PCR-RFLP assays. These 810 North Indian T2DM patients treated with ACEI or ARB after diagnosis were followed up for 3 years. Percent changes in eGFR, urinary albumin excretion (UAE), serum creatinine at the end of 3 years of treatment were taken as end points of renoprotective response.

RESULT

We observed that in normoalbuminuric patients, eNOS -786 CC genotype and haplotypes C-b-G and C-b-T were associated with lesser renoprotective response to ACEI. While, in macroalbuminurics, eNOS -786 CC genotype, haplotypes C-b-G and C-b-T and 27VNTR aa were associated with better renoprotective response to ACEI/ARB.

CONCLUSION

Our results showed that eNOS T-786C CC genotype and 27VNTR individually and in interaction with other eNOS SNPs modulate renoprotective efficacy of ACEI and ARB in T2DM patients, depending on the status of proteinuria.

Antiplatelet agents for chronic kidney disease

BACKGROUND

Antiplatelet agents are widely used to prevent cardiovascular events. The risks and benefits of antiplatelet treatment may be different in people with chronic kidney disease (CKD) for whom occlusive atherosclerotic events are less prevalent, and bleeding hazards might be increased.

OBJECTIVES

To summarise the effects of antiplatelet treatment (antiplatelet agent versus control or other antiplatelet agent) for the prevention of cardiovascular and adverse kidney outcomes in individuals with CKD.

SEARCH METHODS

In January 2011 we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and the Cochrane Renal Group's Specialised Register without language restriction.

SELECTION CRITERIA

We selected randomised controlled trials of any antiplatelet treatment versus placebo or no treatment, or direct head-to-head antiplatelet agent studies in people with CKD. Studies were included if they enrolled participants with CKD, or included people in broader at-risk populations in which data for subgroups with CKD could be disaggregated.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from primary study reports and any available supplementary information for study population, interventions, outcomes, and risks of bias. Risk ratios (RR) and 95% confidence intervals (CI) were calculated from numbers of events and numbers of participants at risk which were extracted from each included study. The reported RRs were extracted where crude event rates were not provided. Data was pooled using the random-effects model.

MAIN RESULTS

We included 50 studies, enrolling 27,139 participants; 44 studies (21,460 participants) compared an antiplatelet agent with placebo or no treatment, and six studies (5679 participants) directly compared one antiplatelet agent with another. Compared to placebo or no treatment, antiplatelet agents reduced the risk of myocardial infarction (17 studies; RR 0.87, 95% CI 0.76 to 0.99), but not all-cause mortality (30 studies; RR 0.93, 95% CI 0.81 to 1.06), cardiovascular mortality (19 studies; RR 0.89, 95% CI 0.70 to 1.12) or stroke (11 studies; RR 1.00, 95% CI 0.58 to 1.72). Antiplatelet agents increased the risk of major (27 studies; RR 1.33, 95% CI 1.10 to 1.65) and minor bleeding (18 studies; RR 1.49, 95% CI 1.12 to 1.97). In terms of dialysis access outcomes, antiplatelet agents reduced access thrombosis or patency failure but had no effect on suitability for dialysis. Meta-regression analysis indicated no differences in the relative benefit or harms of treatment (risk of all-cause mortality, myocardial infarction, or major bleeding) by type of antiplatelet agent or stage of CKD. Limited data were available for direct head-to-head comparisons of antiplatelet drugs, treatment in kidney transplant recipients, primary prevention, or risk of ESKD.

AUTHORS' CONCLUSIONS

Antiplatelet agents reduce myocardial infarction but increase major bleeding. Risks may outweigh harms among people with low annual risks of cardiovascular events, including those with early stages of CKD who do not have clinically-evident occlusive cardiovascular disease.

Advanced oxidation protein products activate intrarenal renin-angiotensin system via a CD36-mediated, redox-dependent pathway

AIMS

Activation of intrarenal renin-angiotensin system (RAS) has a detrimental effect on the progression of chronic kidney diseases (CKDs), although the regulation of intrarenal RAS remains unclear. The aim of the present study was to evaluate the role of advanced oxidation protein products (AOPPs) in intrarenal RAS activation.

RESULTS

AOPPs upregulated the expression of almost all components of RAS and increased activity of angiotensin-converting enzyme in cultured proximal tubular epithelial cells. The triggering effect of AOPP-albumin was 100-times stronger than that of unmodified albumin. The effect of AOPP-albumin was mainly mediated by a CD36-dependent, redox-sensitive signaling involving activation of protein kinase Cα, NADPH oxidase, and nuclear factor-κB/activation protein-1. Chronic AOPP-albumin loading in unilateral nephrectomy rats resulted in deposition of AOPPs in renal tubular cells accompanied with local RAS activation and functional perturbations such as increase in urinary albumin excretion. Accumulation of AOPPs was also detected in human renal tubular cells and correlated with expression of angiotensin II in renal biopsies from 19 patients with IgA nephropathy.

INNOVATION AND CONCLUSION

This study demonstrated for the first time that AOPPs modified albumin functions as a strong trigger of intrarenal RAS via a CD36-mediated, redox-dependent pathway. Given the fact that accumulation of AOPPs is prevalent in diabetes and CKD, targeting AOPPs could be a strategy for the therapeutic intervention of CKD. Antioxid. Redox Signal. 18, 19-35.

Direct Renin inhibitor: aliskiren in chronic kidney disease

The renin-angiotensin-aldosterone system (RAAS) plays pivotal roles in the pathogenesis of chronic kidney disease (CKD) progression and its increased complications such as hypertension (HT) and cardiovascular diseases (CVD). Previous studies suggested that aliskiren a direct renin inhibitor, blocks RAAS and may be effective for the management of CKD and its complications. This review focuses on the effects of aliskiren on CKD.

A meta-analysis reporting effects of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in patients without heart failure

OBJECTIVES

The goal of the study was to assess the effects of angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs) on the composite of cardiovascular (CV) death, myocardial infarction (MI), and stroke, and on all-cause death, new-onset heart failure (HF), and new-onset diabetes mellitus (DM) in high-risk patients without HF.

BACKGROUND

ACE-Is reduce CV events in high-risk patients without HF whereas the effects of ARBs are less certain.

METHODS

Twenty-six randomized trials comparing ARBs or ACE-Is versus placebo in 108,212 patients without HF were collected in a meta-analysis and analyzed for the risk of the composite outcome, all-cause death, new-onset HF, and new-onset DM.

RESULTS

ACE-Is significantly reduced the risk of the composite outcome (odds ratio [OR]: 0.830 [95% confidence interval (CI): 0.744 to 0.927]; p = 0.001), MI (OR: 0.811 [95% CI: 0.748 to 0.879]; p < 0.001), stroke (OR: 0.796 [95% CI: 0.682 to 0.928]; p < 0.004), all-cause death (OR: 0.908 [95% CI: 0.845 to 0.975]; p = 0.008), new-onset HF (OR: 0.789 [95% CI: 0.686 to 0.908]; p = 0.001), and new-onset DM (OR: 0.851 [95% CI: 0.749 to 0.965]; p < 0.012). ARBs significantly reduced the risk of the composite outcome (OR: 0.920 [95% CI: 0.869 to 0.975], p = 0.005), stroke (OR: 0.900 [95% CI: 0.830 to 0.977], p = 0.011), and new-onset DM (OR: 0.855 [95% CI: 0.798 to 0.915]; p < 0.001).

CONCLUSIONS

In patients at high CV risk without HF, ACE-Is and ARBs reduced the risk of the composite outcome of CV death, MI, and stroke. ACE-Is also reduced the risk of all-cause death, new-onset HF, and new-onset DM. Thus, ARBs represent a valuable option to reduce CV mortality and morbidity in patients in whom ACE-Is cannot be used.

The angiotensin II type 1 receptor blocker olmesartan preferentially improves nocturnal hypertension and proteinuria in chronic kidney disease

Accumulated evidence suggests that an altered ambulatory blood pressure (BP) profile, particularly elevated nighttime BP, reflects target organ injury and is a better predictor of further cardiorenal risk than the clinic BP or daytime BP in hypertensive patients complicated by chronic kidney disease (CKD). In this study, we examined the beneficial effects of olmesartan, an angiotensin II type 1 receptor blocker (ARB), on ambulatory BP profiles and renal function in hypertensive CKD patients. Forty-six patients were randomly assigned to the olmesartan add-on group (n=23) or the non-ARB group (n=23). At baseline and after the 16-week treatment period, ambulatory BP monitoring was performed and renal function parameter measurements were collected. Although the baseline clinic BP levels and the after-treatment/baseline (A/B) ratios of clinic BP levels were similar in the olmesartan add-on and non-ARB groups, the A/B ratios of ambulatory 24-h and nighttime BP levels in the olmesartan add-on group were significantly lower. Furthermore, the A/B ratios of urinary protein, albumin and type IV collagen excretion in the olmesartan add-on group were significantly lower than those in the non-ARB group (urinary protein excretion, 0.72±0.41 vs. 1.45±1.48, P=0.030; urinary albumin excretion, 0.73±0.37 vs. 1.50±1.37, P=0.005; urinary type IV collagen excretion, 0.87±0.42 vs. 1.48±0.87, P=0.014) despite comparable A/B ratios for the estimated glomerular filtration rate in the two groups. These results indicate that in hypertensive patients with CKD, olmesartan add-on therapy improves the ambulatory BP profile via a preferential reduction in nighttime BP with concomitant renal injury inhibition.

Emerging concepts in the diagnosis and treatment of patients with undifferentiated angioedema

Angioedema is a sudden, transient swelling of well-demarcated areas of the dermis, subcutaneous tissue, mucosa, and submucosal tissues that can occur with or without urticaria. Up to 25% of people in the US will experience an episode of urticaria or angioedema during their lifetime, and many will present to the emergency department with an acute attack. Most cases of angioedema are attributable to the vasoactive mediators histamine and bradykinin. Histamine-mediated (allergic) angioedema occurs through a type I hypersensitivity reaction, whereas bradykinin-mediated (non-allergic) angioedema is iatrogenic or hereditary in origin.Although their clinical presentations bear similarities, the treatment algorithm for histamine-mediated angioedema differs significantly from that for bradykinin-mediated angioedema. Corticosteroids, and epinephrine are effective in the management of histamine-mediated angioedema but are ineffective in the management of bradykinin-mediated angioedema. Recent advancements in the understanding of angioedema have yielded pharmacologic treatment options for hereditary angioedema, a rare hereditary form of bradykinin-mediated angioedema. These novel therapies include a kallikrein inhibitor (ecallantide) and a bradykinin β2 receptor antagonist (icatibant). The physician's ability to distinguish between these types of angioedema is critical in optimizing outcomes in the acute care setting with appropriate treatment. This article reviews the pathophysiologic mechanisms, clinical presentations, and diagnostic laboratory evaluation of angioedema, along with acute management strategies for attacks.

Educational paper: Progression in chronic kidney disease and prevention strategies

Chronic kidney disease (CKD) in children is a rare but devastating condition. Once a critical amount of nephron mass has been lost, progression of CKD is irreversible and results in end-stage renal disease (ESRD) and need of renal replacement therapy. The time course of childhood CKD is highly variable. While in children suffering from congenital anomalies of the kidneys and the urinary tract, progression of CKD in general is slow, in children with acquired glomerulopathies, disease progression can be accelerated resulting in ESRD within months. However, irrespective of the underlying kidney disease, hypertension and proteinuria are independent risk factors for progression. Thus, in order to prevent progression, the primary objective of treatment should always aim for efficient control of blood pressure and reduction of urinary protein excretion. Blockade of the renin-angiotensin-aldosterone system preserves kidney function not only by lowering blood pressure, but also by reducing proteinuria and exerting additional anti-proteinuric, anti-fibrotic, and anti-inflammatory effects. Besides, intensified blood pressure control, aiming for a target blood pressure below the 50th percentile, may exert additive renoprotective effects. Additionally, other modifiable risk factors, such as anemia, metabolic acidosis, dyslipidemia, and altered bone-mineral homeostasis may also contribute to CKD progression. In conclusion, beyond strict blood pressure control and reduction of urinary protein excretion, identification and treatment of both, renal disease-related and conventional risk factors are mandatory in children with CKD in order to prevent deterioration of kidney function.

Hypertension in the metabolic syndrome

Increased blood pressure is considered an important component of metabolic syndrome. More than 85% of those with metabolic syndrome, even in the absence of diabetes, have elevated blood pressure (BP) or hypertension. The association of elevated BP with the metabolic syndrome is strongly linked through the causative pathway of obesity. Hypertension is the leading metabolic syndrome risk factor that predisposes to increased cardiovascular morbidity and mortality, and is additionally an important risk factor for development of chronic kidney disease in the presence of obesity, the metabolic syndrome, and microalbuminuria. Control of blood pressure in persons with the metabolic syndrome may prevent a significant number of coronary heart disease events. The primary modality of treatment is lifestyle intervention with reduced caloric intake and increased physical activity. Pharmacologic intervention is indicated on the basis of the severity of BP elevation, associated cardiovascular risk factors, and the presence of target organ damage.

Surrogate end points: how well do they represent patient-relevant end points?

This review takes a critical look at the concept of replacing patient-relevant end points, such as morbidity or mortality, with surrogate end points in clinical trials. Surrogate end points can be measured earlier in the course of a clinical trial and so are thought to accelerate the drug development process. Furthermore, they might be beneficial to the patients themselves by allowing faster adjustment of therapeutic strategies. However, the fact that in the past several promising surrogate end points have not fulfilled their expectations emphasizes the importance of applying strict evaluation criteria. The evaluation of the candidate surrogate end point prostate-specific antigen using the Prentice criteria and a meta-analytic approach is discussed. Prostate-specific antigen is often used to replace overall or progression-free survival in prostate cancer trials testing the benefit of medical interventions.

Serum uric acid independently predicts cardiovascular events in advanced nephropathy

BACKGROUND

Chronic kidney disease (CKD) is associated with increased risk for cardiovascular (CV) disease and is also associated with elevated uric acid, which is emerging as a nontraditional CV risk factor. We therefore evaluated uric acid as a risk factor for CV disease in subjects presenting to nephrologists with CKD who were not on medications known to alter endothelial function.

METHODS

303 subjects with stage 3-5 CKD were followed for a mean of 39 months (range 6-46) and assessed for fatal and nonfatal CV events. Hyperuricemia was defined as uric acid >6.0 mg/dl for women and >7.0 mg/dl for men. In addition to other CV risk factors, endothelial function (flow-mediated dilatation), inflammatory markers (hsCRP), and insulin resistance (HOMA index and fasting insulin levels) were included in the analysis. We evaluated the association between uric acid and flow-mediated dilatation with linear regression. The impact of uric acid on composite CV events was assessed with Cox regression analysis.

RESULTS

Of a total of 303 patients, 89 had normouricemia and 214 had hyperuricemia. Both fatal (32 of 214 vs. 1 of 89 subjects) and combined fatal and nonfatal (100 of 214 vs. 13 of 89 subjects) CV events were more common in subjects with hyperuricemia compared with normal uric acid levels, and this was independent of estimated glomerular filtration rate, traditional CV risk factors including diabetes, hypertension and BMI, and nontraditional risk factors (hsCRP and endothelial function). The 46-month survival rate was 98.7% in the group with low uric acid compared to 85.8% in patients with high uric acid (p = 0.002).

CONCLUSIONS

Hyperuricemia is an independent risk factor for CV events in subjects presenting with CKD who are not on medications known to alter endothelial function.

A guide to the management of blood pressure in the diabetic hypertensive patient

Diabetes mellitus and hypertension frequently coexist in patients with the insulin resistance syndrome (IRS). Patients with both diabetes and hypertension typically have widespread endothelial dysfunction, increased oxidative stress, an activated sympathoadrenal system, and an elevated systemic burden of inflammatory mediators. Patients with diabetes and hypertension also have concomitant mixed dyslipidemia and obesity with significant frequency, and are at high risk for the development of macro- and microvascular disease, congestive heart failure, and nephropathy. Current data suggest that ACE inhibitors or angiotensin receptor blockers with or without a diuretic are important, if not preferred, initial therapies for the patient with diabetes and hypertension. Other drug classes such as combined alpha-/beta-adrenoceptor antagonists, dihydropyridine calcium channel antagonists (CCAs), and peripheral alpha-adrenoceptor antagonists are also useful therapeutic options in these patients. In order to optimally reduce the risk for cardiovascular events in the patient with diabetes and hypertension, optimal BP control should be coupled with comprehensive lifestyle modification and aggressive management of dyslipidemia and hyperglycemia.

Chronic kidney disease and vascular remodelling: molecular mechanisms and clinical implications

CKD (chronic kidney disease) is a severe and complex disease with a very high prevalence of CV (cardiovascular) complications. CKD patients are exposed to haemodynamic disturbances in addition to severe metabolic abnormalities that lead to a specific form of arterial remodelling, which contributes to the development of CV disease. Arterial calcification is a major event in the arterial remodelling process and is strongly linked to mineral metabolism abnormalities associated with CKD. Arterial remodelling is not limited to arterial calcification and modifications in arterial wall composition are also observed. Activation of the RAS (renin-angiotensin system), ET-1 (endothelin-1), endothelial dysfunction, oxidative stress and ADMA (asymmetric ω-NG,NG-dimethylarginine), as well as the anti-aging molecule Klotho, are implicated in this process. The present review details the mechanisms involved in arterial calcification and arterial remodelling associated with CKD, and provides the clinical consequences of large and small artery stiffness and remodelling in CKD patients.

Current drug development challenges in chronic kidney disease (CKD)--identification of individualized determinants of renal progression and premature cardiovascular disease (CVD)

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are currently considered as major health burdens. Notably, CKD can be regarded as an interesting clinical model of accelerated cardiovascular disease (CVD) and ageing, which offers exciting new perspectives and challenges for pharmaceutical drug development. However, during the last decades, therapeutic advances to slow down the progression of CKD and reduce CVD risk have largely failed due to several possible reasons including (i) the lack of profound understanding of the pathophysiology of chronic renal damage and its associated CVD; (ii) an inadequate characterization of molecular mechanisms of currently approved therapies such as renin-angiotensin-aldosterone-system (RAAS) blockade; (iii) the unclear biochemical property needs required for novel therapeutic approaches; (iv) the missing quantity and quality of clinical trials in the nephrology field; and, most importantly, (v) the absence of prognostic renal biomarkers that reflect the severity of the structural organ damage and predict ESRD as well as CVD mortality. There is clearly an insufficient understanding of why a significant proportion of CKD patients progress to ESRD and/or die from CVD whereas others rather remain stable. In this article, we urge renal researchers to develop novel experimental and clinical tools for rational and translational drug discovery. Identification of individualized determinants of CKD progression and/or premature CVD will enable personalized medicine and lead to novel innovative nephro- and/or cardioprotective pharmacological treatment in these high-risk patients.

Updated report on comparative effectiveness of ACE inhibitors, ARBs, and direct renin inhibitors for patients with essential hypertension: much more data, little new information

OBJECTIVES

A 2007 systematic review compared angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in patients with hypertension. Direct renin inhibitors (DRIs) have since been introduced, and significant new research has been published. We sought to update and expand the 2007 review.

DATA SOURCES

We searched MEDLINE and EMBASE (through December 2010) and selected other sources for relevant English-language trials.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

We included studies that directly compared ACE inhibitors, ARBs, and/or DRIs in at least 20 total adults with essential hypertension; had at least 12 weeks of follow-up; and reported at least one outcome of interest. Ninety-seven (97) studies (36 new since 2007) directly comparing ACE inhibitors versus ARBs and three studies directly comparing DRIs to ACE inhibitor inhibitors or ARBs were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

A standard protocol was used to extract data on study design, interventions, population characteristics, and outcomes; evaluate study quality; and summarize the evidence.

RESULTS

In spite of substantial new evidence, none of the conclusions from the 2007 review changed. The level of evidence remains high for equivalence between ACE inhibitors and ARBs for blood pressure lowering and use as single antihypertensive agents, as well as for superiority of ARBs for short-term adverse events (primarily cough). However, the new evidence was insufficient on long-term cardiovascular outcomes, quality of life, progression of renal disease, medication adherence or persistence, rates of angioedema, and differences in key patient subgroups.

LIMITATIONS

Included studies were limited by follow-up duration, protocol heterogeneity, and infrequent reporting on patient subgroups.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Evidence does not support a meaningful difference between ACE inhibitors and ARBs for any outcome except medication side effects. Few, if any, of the questions that were not answered in the 2007 report have been addressed by the 36 new studies. Future research in this area should consider areas of uncertainty and be prioritized accordingly.

Relationship of ambulatory blood pressure and the heart rate profile with renal function parameters in hypertensive patients with chronic kidney disease

Strict blood pressure (BP) control is reportedly important for the management of hypertensive patients with chronic kidney disease (CKD). The purpose of this cross-sectional study was to examine whether the variables of ambulatory BP and the heart rate (HR) profile, central hemodynamics, and arterial stiffness were closely related to the renal function parameters (urine albumin excretion rate [UACR] and estimated glomerular filtration rate [eGFR]) observed in 25 consecutive hospitalized hypertensive patients with CKD. There were significant positive relationships between UACR and 24-hour, daytime, and nighttime ambulatory systolic BP. In addition, there were significant negative relationships between UACR and 24-hour and daytime HR variability. The circulating B-type natriuretic peptide level and hemoglobin A1c were also positively related to UACR. With respect to eGFR, although the 24-hour and nighttime HR variability were positively associated with eGFR, the circulating pentosidine and nighttime HR had a negative relationship with eGFR. On the other hand, central hemodynamics and arterial stiffness did not exhibit any significant association with renal function parameters. These results indicate that ambulatory BP and the HR profile are closely modulated by renal function deterioration. Further studies are needed to investigate the causal relationship between ambulatory BP and the HR profile and renal function parameters in hypertensive patients with CKD.

Early treatment with olmesartan prevents juxtamedullary glomerular podocyte injury and the onset of microalbuminuria in type 2 diabetic rats

BACKGROUND

Studies were performed to determine if early treatment with an angiotensin II (Ang II) receptor blocker (ARB), olmesartan, prevents the onset of microalbuminuria by attenuating glomerular podocyte injury in Otsuka Long-Evans Tokushima Fatty (OLETF) rats with type 2 diabetes mellitus.

METHODS

OLETF rats were treated with either a vehicle, olmesartan (10 mg/kg/day) or a combination of nonspecific vasodilators (hydralazine 15 mg/kg/day, hydrochlorothiazide 6 mg/kg/day, and reserpine 0.3 mg/kg/day; HHR) from the age of 7-25 weeks.

RESULTS

OLETF rats were hypertensive and had microalbuminuria from 9 weeks of age. At 15 weeks, OLETF rats had higher Ang II levels in the kidney, larger glomerular desmin-staining areas (an index of podocyte injury), and lower gene expression of nephrin in juxtamedullary glomeruli, than nondiabetic Long-Evans Tokushima Otsuka (LETO) rats. At 25 weeks, OLETF rats showed overt albuminuria, and higher levels of Ang II in the kidney and larger glomerular desmin-staining areas in superficial and juxtamedullary glomeruli compared to LETO rats. Reductions in mRNA levels of nephrin were also observed in superficial and juxtamedullary glomeruli. Although olmesartan did not affect glucose metabolism, it decreased blood pressure and prevented the renal changes in OLETF rats. HHR treatment also reduced blood pressure, but did not affect the renal parameters.

CONCLUSIONS

This study demonstrated that podocyte injury occurs in juxtamedullary glomeruli prior to superficial glomeruli in type 2 diabetic rats with microalbuminuria. Early treatment with an ARB may prevent the onset of albuminuria through its protective effects on juxtamedullary glomerular podocytes.

Exploring metabolic dysfunction in chronic kidney disease

Impaired kidney function and chronic kidney disease (CKD) leading to kidney failure and end-stage renal disease (ESRD) is a serious medical condition associated with increased morbidity, mortality, and in particular cardiovascular disease (CVD) risk. CKD is associated with multiple physiological and metabolic disturbances, including hypertension, dyslipidemia and the anorexia-cachexia syndrome which are linked to poor outcomes. Specific hormonal, inflammatory, and nutritional-metabolic factors may play key roles in CKD development and pathogenesis. These include raised proinflammatory cytokines, such as interleukin-1 and −6, tumor necrosis factor, altered hepatic acute phase proteins, including reduced albumin, increased C-reactive protein, and perturbations in normal anabolic hormone responses with reduced growth hormone-insulin-like growth factor-1 axis activity. Others include hyperactivation of the renin-angiotensin aldosterone system (RAAS), with angiotensin II and aldosterone implicated in hypertension and the promotion of insulin resistance, and subsequent pharmacological blockade shown to improve blood pressure, metabolic control and offer reno-protective effects. Abnormal adipocytokine levels including leptin and adiponectin may further promote the insulin resistant, and proinflammatory state in CKD. Ghrelin may be also implicated and controversial studies suggest activities may be reduced in human CKD, and may provide a rationale for administration of acyl-ghrelin. Poor vitamin D status has also been associated with patient outcome and CVD risk and may indicate a role for supplementation. Glucocorticoid activities traditionally known for their involvement in the pathogenesis of a number of disease states are increased and may be implicated in CKD-associated hypertension, insulin resistance, diabetes risk and cachexia, both directly and indirectly through effects on other systems including activation of the mineralcorticoid receptor. Insight into the multiple factors altered in CKD may provide useful information on disease pathogenesis, clinical assessment and treatment rationale such as potential pharmacological, nutritional and exercise therapies.

Effects of renin-angiotensin system blockades on cardiovascular outcomes in patients with diabetes mellitus: A systematic review and meta-analysis

AIM

To determine whether renin-angiotensin system (RAS) blockade is beneficial for cardiovascular outcomes in patients with diabetes mellitus (DM) using meta-analysis.

METHODS

The MEDLINE and Cochrane library databases were searched for randomized controlled trials published up to June 2010. We also reviewed reference lists from identified trials and review articles to identify any other relevant studies, and the ClinicalTrials.gov website to identify randomized controlled trials that were registered as completed but not yet published. A random-effects model was used to combine the estimates for risk ratios (RR).

RESULTS

Eligible studies were randomized controlled trials (including post hoc analyses) assessing the effects of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers on cardiovascular events compared to controls in patients with DM. Nineteen clinical trials with 41,042 patients and 6039 cardiovascular events were identified. RAS blockade significantly reduced the risk of major cardiovascular events (RR 0.92, 95% confidence interval [CI] 0.84-1.00, I(2) statistic 53%) and myocardial infarction (RR 0.82, 95% CI 0.72-0.94, I(2)=55%). There were trends towards fewer strokes and lower all-cause mortality but these were not statistically significant.

CONCLUSIONS

The available evidence shows that treatment with RAS blockade can routinely be considered for diabetic patients to reduce major cardiovascular events.

Tight blood pressure control in diabetes: evidence-based review of treatment targets in patients with diabetes

Blood pressure (BP) targets in diabetic patients stills represent the object of a major debate, fueled by the recent publication of post hoc observational analyses of the INVEST and the ONTARGET trials, suggesting an increased risk of cardiovascular events with tighter control, the J-curve effect, and by the results of the ACCORD trial, showing no improvements in the composite primary outcome of nonfatal myocardial infarction, stroke, or cardiovascular death in the intensive BP-lowering arm (<120/80 mmHg). In the present review, we focus on existing evidence about different BP targets in diabetic subjects and we present the results of our recent meta-analysis, showing that tight BP control may significantly reduce the risk of stroke in these patients without increasing the risk of myocardial infarction. Therapeutic inertia (leaving diabetic patients with BP values of 140/90 mmHg or higher) should be avoided at all costs, as this would lead to an unacceptable toll in terms of human lives, suffering, and socioeconomic costs.

Comparative effectiveness of renin-angiotensin system inhibitors in hypertension

Hypertension is a chronic problem in the USA and there are three main ways to block the renin-angiotensin system: direct renin inhibitors, angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). This article is a summary of a direct comparative effectiveness review of direct comparative trials in patients with hypertension. In patients with hypertension, ACEIs and ARBs provide similar blood pressure effects and no differences were seen in final health outcomes. ARBs have less ACE-induced cough and fewer withdrawals due to adverse events. Direct renin inhibitors versus ACE inhibitors or ARBs have not been extensively studied and their role is less clear.