Differing Anti-Proteinuric Action of Candesartan and Losartan in Chronic Renal Disease

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers for adults with early (stage 1 to 3) non-diabetic chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a long-term condition that occurs as a result of damage to the kidneys. Early recognition of CKD is becoming increasingly common due to widespread laboratory estimated glomerular filtration rate (eGFR) reporting, raised clinical awareness, and international adoption of the Kidney Disease Improving Global Outcomes (KDIGO) classifications. Early recognition and management of CKD affords the opportunity to prepare for progressive kidney impairment and impending kidney replacement therapy and for intervention to reduce the risk of progression and cardiovascular disease. Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are two classes of antihypertensive drugs that act on the renin-angiotensin-aldosterone system. Beneficial effects of ACEi and ARB on kidney outcomes and survival in people with a wide range of severity of kidney impairment have been reported; however, their effectiveness in the subgroup of people with early CKD (stage 1 to 3) is less certain. This is an update of a review that was last published in 2011.

OBJECTIVES

To evaluate the benefits and harms of ACEi and ARB or both in the management of people with early (stage 1 to 3) CKD who do not have diabetes mellitus (DM).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 6 July 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and Embase, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) reporting the effect of ACEi or ARB in people with early (stage 1 to 3) CKD who did not have DM were selected for inclusion. Only studies of at least four weeks duration were selected. Authors independently assessed the retrieved titles and abstracts and, where necessary, the full text to determine which satisfied the inclusion criteria.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out by two authors independently, using a standard data extraction form. The methodological quality of included studies was assessed using the Cochrane risk of bias tool. Data entry was carried out by one author and cross-checked by another. When more than one study reported similar outcomes, data were pooled using the random-effects model. Heterogeneity was analysed using a Chi² test and the I² test. Results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach MAIN RESULTS: Six studies randomising 9379 participants with CKD stages 1 to 3 (without DM) met our inclusion criteria. Participants were adults with hypertension; 79% were male from China, Europe, Japan, and the USA. Treatment periods ranged from 12 weeks to three years. Overall, studies were judged to be at unclear or high risk of bias across all domains, and the quality of the evidence was poor, with GRADE rated as low or very low certainty. In low certainty evidence, ACEi (benazepril 10 mg or trandolapril 2 mg) compared to placebo may make little or no difference to death (any cause) (2 studies, 8873 participants): RR 2.00, 95% CI 0.26 to 15.37; I² = 76%), total cardiovascular events (2 studies, 8873 participants): RR 0.97, 95% CI 0.90 to 1.05; I² = 0%), cardiovascular-related death (2 studies, 8873 participants): RR 1.73, 95% CI 0.26 to 11.66; I² = 54%), stroke (2 studies, 8873 participants): RR 0.76, 95% CI 0.56 to 1.03; I² = 0%), myocardial infarction (2 studies, 8873 participants): RR 1.00, 95% CI 0.84 to 1.20; I² = 0%), and adverse events (2 studies, 8873 participants): RR 1.33, 95% CI 1.26 to 1.41; I² = 0%). It is uncertain whether ACEi (benazepril 10 mg or trandolapril 2 mg) compared to placebo reduces congestive heart failure (1 study, 8290 participants): RR 0.75, 95% CI 0.59 to 0.95) or transient ischaemic attack (1 study, 583 participants): RR 0.94, 95% CI 0.06 to 15.01; I² = 0%) because the certainty of the evidence is very low. It is uncertain whether ARB (losartan 50 mg) compared to placebo (1 study, 226 participants) reduces: death (any-cause) (no events), adverse events (RR 19.34, 95% CI 1.14 to 328.30), eGFR rate of decline (MD 5.00 mL/min/1.73 m2, 95% CI 3.03 to 6.97), presence of proteinuria (MD -0.65 g/24 hours, 95% CI -0.78 to -0.52), systolic blood pressure (MD -0.80 mm Hg, 95% CI -3.89 to 2.29), or diastolic blood pressure (MD -1.10 mm Hg, 95% CI -3.29 to 1.09) because the certainty of the evidence is very low. It is uncertain whether ACEi (enalapril 20 mg, perindopril 2 mg or trandolapril 1 mg) compared to ARB (olmesartan 20 mg, losartan 25 mg or candesartan 4 mg) (1 study, 26 participants) reduces: proteinuria (MD -0.40, 95% CI -0.60 to -0.20), systolic blood pressure (MD -3.00 mm Hg, 95% CI -6.08 to 0.08) or diastolic blood pressure (MD -1.00 mm Hg, 95% CI -3.31 to 1.31) because the certainty of the evidence is very low.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to determine the effectiveness of ACEi or ARB in patients with stage 1 to 3 CKD who do not have DM. The available evidence is overall of very low certainty and high risk of bias. We have identified an area of large uncertainty for a group of patients who account for most of those diagnosed as having CKD.

TMAO Suppresses Megalin Expression and Albumin Uptake in Human Proximal Tubular Cells Via PI3K and ERK Signaling

Trimethylamine-N-oxide (TMAO) is a uremic toxin, which has been associated with chronic kidney disease (CKD). Renal tubular epithelial cells play a central role in the pathophysiology of CKD. Megalin is an albumin-binding surface receptor on tubular epithelial cells, which is indispensable for urine protein reabsorption. To date, no studies have investigated the effect of TMAO on megalin expression and the functional properties of human tubular epithelial cells. The aim of this study was first to identify the functional effect of TMAO on human renal proximal tubular cells and second, to unravel the effects of TMAO on megalin-cubilin receptor expression. We found through global gene expression analysis that TMAO was associated with kidney disease. The microarray analysis also showed that megalin expression was suppressed by TMAO, which was also validated at the gene and protein level. High glucose and TMAO was shown to downregulate megalin expression and albumin uptake similarly. We also found that TMAO suppressed megalin expression via PI3K and ERK signaling. Furthermore, we showed that candesartan, dapagliflozin and enalaprilat counteracted the suppressive effect of TMAO on megalin expression. Our results may further help us unravel the role of TMAO in CKD development and to identify new therapeutic targets to counteract TMAOs effects.

Effect of angiotensin receptor blockers on blood pressure and renal function in patients with concomitant hypertension and chronic kidney disease: a systematic review and meta-analysis

Objective: Angiotensin receptor blockers (ARB) are among the recommended first-line treatment options in patients with hypertension and chronic kidney disease (CKD). This meta-analysis evaluated the effect of ARB on blood pressure (BP) and renal function in patients with concomitant hypertension and CKD with or without diabetes.Methods: Literature search was performed in PubMed/MEDLINE, EMBASE and BIOSIS to identify parallel-group, randomized controlled trials (≥8 weeks) reporting the effects of ARB on office systolic/diastolic BP (SBP/DBP), estimated glomerular filtration rate (eGFR), serum creatinine (SCr), creatinine clearance (CrCl) or proteinuria in adults with hypertension and CKD. Mean difference (MD, generic inverse variance) with 95% confidence intervals (CIs) was used to report an outcome.Results: Among the 24 studies identified, 19 evaluated ARB as monotherapy, 4 evaluated ARB as combination therapy and one evaluated ARB both as monotherapy and combination therapy. Median (range) duration of the studies was 12 (1.84-54.0) months. ARB monotherapy significantly (p < 0.01) reduced BP (treatment ≥1 year: SBP [MD: -14.84 mmHg; 95% CI: -17.82 to -11.85]/DBP [-10.27 mmHg; -12.26 to -8.27]) and proteinuria (≥1 year [-0.90 g/L; -1.22 to -0.59]). Results were consistent for combination therapy. In these studies, non-significant changes were observed for eGFR, CrCl and SCr. The impact of SBP changes on eGFR was not significant; however, studies were of a relatively short duration.Conclusion: ARB had a favorable impact on BP and renal parameters such as proteinuria with monotherapy as well as with combination therapy, highlighting their potential benefits in patients with hypertension and CKD. During the short follow-up of these studies, no significant change in eGFR was observed.

Angiotensin II receptor blockade reduces salt sensitivity of blood pressure through restoration of renal nitric oxide synthesis in patients with diabetic nephropathy

INTRODUCTION

We have previously demonstrated the increased salt sensitivity of blood pressure (BP) in diabetic patients with early nephropathy. Here, we examined the effects of an angiotensin II receptor blocker (ARB) on salt sensitivity and renal oxidative stress or nitric oxide (NO) in those patients.

PATIENTS AND METHODS

Type 2 diabetic patients with (n = 6) and without (n = 6) microalbuminuria were studied on a high-salt diet for one week and on a salt-restricted diet for one week. The study was repeated in the patients with microalbuminuria during treatment with an ARB, valsartan (80 mg/day). Salt sensitivity was assessed from the BP/sodium excretion curve. Urinary excretion rates of NOx, 8-hydroxy-2-deoxyguanosine as a marker of oxidative stress, and plasma tetrahydrobiopterin as a cofactor for NO synthase were measured.

RESULTS

Compared with diabetic patients without microalbuminuria, patients with microalbuminuria showed greater salt sensitivity and lower urinary excretion of NOx. In the patients with microalbuminuria, treatment with valsartan reduced salt sensitivity in association with increased NOx excretion, reduced 8-hydroxy-2,-deoxyguanosine excretion, and increased plasma tetrahydrobiopterin levels.

CONCLUSIONS

These data support the hypothesis that ARBs reduce the salt sensitivity of BP by decreasing renal oxidative stress and restoring NO activity in diabetic patients with microalbuminuria.

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers for adults with early (stage 1 to 3) non-diabetic chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a long term condition that occurs as a result of damage to the kidneys. Early recognition of CKD is becoming increasingly common due to widespread laboratory estimated glomerular filtration rate (eGFR) reporting, raised clinical awareness, and international adoption of Kidney Disease Outcomes Quality Initiative (K/DOQI) classification. Early recognition and management of CKD affords the opportunity not only to prepare for progressive kidney impairment and impending renal replacement therapy, but also for intervening to reduce the risk of progression and cardiovascular disease. Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are two classes of antihypertensive drugs that act on the renin-angiotensin-aldosterone system. Beneficial effects of ACEi and ARB on renal outcomes and survival in people with a wide range of severity of renal impairment have been reported; however, their effectiveness in the subgroup of people with early CKD (stage 1 to 3) is less certain.

OBJECTIVES

This review aimed to evaluate the benefits and harms of ACEi and ARB or both in the management of people with early (stage 1 to 3) CKD who do not have diabetes mellitus.

SEARCH STRATEGY

In March 2010 we searched The Cochrane Library, including The Cochrane Renal Group's specialised register and The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Reference lists of review articles and relevant studies were also checked. The search was conducted using the optimally sensitive strategy developed by the Cochrane Collaboration for the identification of randomised controlled trials (RCTs) with input from an expert in trial search strategy.

SELECTION CRITERIA

All RCTs reporting the effect of ACEi or ARB in people with early (stage 1 to 3) CKD who did not have diabetes mellitus were selected for inclusion. Only studies of at least four weeks duration were selected. Authors, working in teams of two, independently assessed the retrieved titles and abstracts, and whenever necessary the full text of these studies were screened to determine which studies satisfied the inclusion criteria.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out by two authors, independently, using a standard data extraction form and cross checked by two other authors. Methodological quality of included studies was assessed using the Cochrane risk of bias tool. Data entry was carried out by one author and cross checked by another author. When more than one study reported similar outcomes, data were pooled using the random-effects model, but a fixed-effect model was also analysed to ensure the robustness of the model chosen and to check susceptibility to outliers. Heterogeneity was analysed using a Chi² test on N-1 degrees of freedom, with an alpha of 0.05 used for statistical significance and with the I² test. Where data permitted, subgroup analysis was used to explore possible sources of heterogeneity. The quality of the evidence was analysed.

MAIN RESULTS

Four RCTs enrolling 2177 participants met our inclusion criteria. Of these, three compared ACEi with placebo and one compared ACEi with ARB. Two studies had an overall low risk of bias, and the other two were considered to be at moderate to high risk of bias. Low to moderate quality of evidence (from two studies representing 1906 patients) suggested that ACEi had no impact on all-cause mortality (RR 1.80, 95% CI 0.17 to 19.27, P = 0.63) or cardiovascular events (RR 0.87, 95% CI 0.66 to 1.14, P = 0.31) in people with stage 3 CKD. For all-cause mortality, there was substantial heterogeneity in the results. One study (quality assessment: low risk of bias) reported no difference in the risk of end-stage kidney disease in those with an eGFR > 45 mL/min/1.74 m² treated with ACEi versus placebo (RR 1.00, 95% CI 0.09 to 1.11, P = 0.99). The (high risk of bias) study that compared ACEi with ARB reported little difference in effect between the treatments when urinary protein, blood pressure or creatinine clearance were compared. No published studies comparing ARB with placebo or ACEi and ARB with placebo were identified.

AUTHORS' CONCLUSIONS

Our review demonstrated that there is currently insufficient evidence to determine the effectiveness of ACEi or ARB in patients with stage 1 to 3 CKD who do not have diabetes mellitus. We have identified an area of significant uncertainty for a group of patients who account for most of those labelled as having CKD.

Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and combined therapy in patients with micro- and macroalbuminuria and other cardiovascular risk factors: a systematic review of randomized controlled trials

BACKGROUND

A recent clinical trial showed harmful renal effects with the combined use of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin-II receptor blockers (ARB) in people with diabetes or vascular disease. We examined the benefits and risks of these agents in people with albuminuria and one or more cardiovascular risk factors.

METHODS

MEDLINE, EMBASE and Renal Health Library were searched for trials comparing ACEI, ARB or their combination with placebo or with one another in people with albuminuria and one or more cardiovascular risk factor.

RESULTS

Eighty-five trials (21,708 patients) were included. There was no significant reduction in the risk of all-cause mortality or fatal cardiac-cerebrovascular outcomes with ACEI versus placebo, ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. There was a significant reduction in the risk of nonfatal cardiovascular events with ACEI versus placebo but not with ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. Development of end-stage kidney disease and progression of microalbuminuria to macroalbuminuria were reduced significantly with ACEI versus placebo and ARB versus placebo but not with combined therapy with ACEI + ARB versus monotherapy.

CONCLUSIONS

ACEI and ARB exert independent renal and nonfatal cardiovascular benefits while their effects on mortality and fatal cardiovascular disease are uncertain. There is a lack of evidence to support the use of combination therapy. A comparative clinical trial with ACE, ARB and its combination in people with albuminuria and a cardiovascular risk factor is warranted.

Comparison of the influence of angiotensin-converting enzyme inhibitor lisinopril and angiotensin II receptor antagonist losartan in patients with idiopathic membranous nephropathy and nephrotic syndrome

OBJECTIVE

In this prospective study, the effects of an angiotensin-converting enzyme inhibitor [lisinopril (LIS)] and an angiotensin II receptor antagonist [losartan (LOS)] were compared in nephrotic patients with idiopathic membranous nephropathy.

MATERIAL AND METHODS

Twenty-seven patients (13 males, mean age +/- SD 51.3 +/- 15.4 years) were treated with LIS (13 patients, six males, mean age 52.1 +/- 15.3 years) or LOS (14 patients, seven males, mean age 50.5 +/- 15.5 years) for 12 months. At baseline and after the treatment period, serum albumin, total cholesterol, estimated glomerular filtration rate (GFR), 24 h proteinuria and mean arterial pressure were determined.

RESULTS

Proteinuria (g/24 h) was significantly reduced in both groups (LIS from 4.82 +/- 1.26 to 1.75 +/- 0.64, p < 0.0001; LOS from 4.55 +/- 1.09 to 2.54 +/- 1.94, p = 0.002) (all results +/- SD). Serum albumin levels (g/dl) increased significantly in both groups (LIS 2.27 +/- 0.41 to 3.17 +/- 0.63, p < 0.0001; LOS 2.93 +/- 0.40 to 3.55 +/- 0.44, p < 0.0001). GFR (ml/min x 1.73 m(2)) did not change significantly in either group (LIS 55 +/- 17 to 56 +/- 17, p = 0.65; LOS 64 +/- 18 to 59 +/- 16, p = 0.13). Total cholesterol (mg/dl) was significantly reduced only in the lisinopril group (LIS 347 +/- 81 to 266 +/- 64, p < 0.0001; LOS 306 +/- 58 to 263 +/- 77, p = 0.138). Mean arterial pressure (mmHg) was reduced in both groups (LIS 107 +/- 12 to 95 +/- 6, p < 0.0001; LOS 104 +/- 10 to 96 +/- 5, p = 0.003). In the comparison between the two groups, serum albumin levels were higher in the losartan group at baseline (p < 0.0001) and after 12 months (p = 0.029). There were no significant differences between the baseline and end-of-study values for the rest of the studied parameters.

CONCLUSION

Treatment with lisinopril and losartan in nephrotic patients with idiopathic membranous nephropathy results in similar (and significant) effects on renal function, hypoalbuminaemia, proteinuria and blood pressure.

A small difference in the molecular structure of angiotensin II receptor blockers induces AT₁ receptor-dependent and -independent beneficial effects

Angiotensin II (Ang II) type 1 (AT₁) receptor blockers (ARBs) induce multiple pharmacological beneficial effects, but not all ARBs have the same effects and the molecular mechanisms underlying their actions are not certain. In this study, irbesartan and losartan were examined because of their different molecular structures (irbesartan has a cyclopentyl group whereas losartan has a chloride group). We analyzed the binding affinity and production of inositol phosphate (IP), monocyte chemoattractant protein-1 (MCP-1) and adiponectin. Compared with losartan, irbesartan showed a significantly higher binding affinity and slower dissociation rate from the AT₁ receptor and a significantly higher degree of inverse agonism and insurmountability toward IP production. These effects of irbesartan were not seen with the AT₁-Y113A mutant receptor. On the basis of the molecular modeling of the ARBs-AT₁ receptor complex and a mutagenesis study, the phenyl group at Tyr(113) in the AT₁ receptor and the cyclopentyl group of irbesartan may form a hydrophobic interaction that is stronger than the losartan-AT₁ receptor interaction. Interestingly, irbesartan inhibited MCP-1 production more strongly than losartan. This effect was mediated by the inhibition of nuclear factor-kappa B activation that was independent of the AT₁ receptor in the human coronary endothelial cells. In addition, irbesartan, but not losartan, induced significant adiponectin production that was mediated by peroxisome proliferator-activated receptor-γ activation in 3T3-L1 adipocytes, and this effect was not mediated by the AT₁ receptor. In conclusion, irbesartan induced greater beneficial effects than losartan due to small differences between their molecular structures, and these differential effects were both dependent on and independent of the AT₁ receptor.

Comparing angiotensin II receptor blockers on benefits beyond blood pressure

The renin-angiotensin-aldosterone system (RAAS) is one of the main regulators of blood pressure, renal hemodynamics, and volume homeostasis in normal physiology, and contributes to the development of renal and cardiovascular (CV) diseases. Therefore, pharmacologic blockade of RAAS constitutes an attractive strategy in preventing the progression of renal and CV diseases. This concept has been supported by clinical trials involving patients with hypertension, diabetic nephropathy, and heart failure, and those after myocardial infarction. The use of angiotensin II receptor blockers (ARBs) in clinical practice has increased over the last decade. Since their introduction in 1995, seven ARBs have been made available, with approved indications for hypertension and some with additional indications beyond blood pressure reduction. Considering that ARBs share a similar mechanism of action and exhibit similar tolerability profiles, it is assumed that a class effect exists and that they can be used interchangeably. However, pharmacologic and dosing differences exist among the various ARBs, and these differences can potentially influence their individual effectiveness. Understanding these differences has important implications when choosing an ARB for any particular condition in an individual patient, such as heart failure, stroke, and CV risk reduction (prevention of myocardial infarction). A review of the literature for existing randomized controlled trials across various ARBs clearly indicates differences within this class of agents. Ongoing clinical trials are evaluating the role of ARBs in the prevention and reduction of CV rates of morbidity and mortality in high-risk patients.

Comparison of the efficacy of candesartan and losartan: a meta-analysis of trials in the treatment of hypertension

Informed by the findings from prospective observational studies and randomized outcome trials, guidelines for the management of hypertension acknowledge that the benefit of treatment can be attributed largely to blood pressure (BP) reduction. Therefore, quantification of differential BP lowering of different agents within classes of anti-hypertensives is of practical importance. The objective of this analysis was to compare the efficacy of candesartan and losartan with respect to reduction in systolic and diastolic BP (SBP and DBP). A systematic literature search of databases from 1980 to 1 October 2008 identified 13 studies in which candesartan and losartan were compared in randomized trials in hypertensive patients. Data from 4066 patients were included in the analysis using a random effect model. Mean changes in SBP and DBP were compared for each drug alone and after stratification for dose and for combination with hydrochlorothiazide (HCTZ). On the basis of all the data, the weighted mean difference favoured candesartan-3.22 mm Hg (95% confidence interval (CI) 2.16, 4.29) for SBP and 2.21 mm Hg (95% CI 1.34, 3.07) for DBP. These findings were consistent when analyses according to dose and combination with HCTZ were carried out. Thus, it can be concluded that at currently recommended doses, candesartan is more effective than losartan in lowering BP.

Which strategy is more effective for the treatment of cardiovascular disease: high-dose angiotensin II type 1 receptor antagonist monotherapy or combination therapy?

Angiotensin II type 1 (AT(1)) receptor antagonists (blockers) [ARBs] are highly selective for the AT(1) receptor and block the diverse effects of angiotensin II. When high BP is not controlled by low-dose ARB monotherapy, physicians need to employ another strategy, either high-dose ARB monotherapy or combination therapy with calcium channel antagonists (blockers) [CCBs], diuretics, or other agents. High-dose ARB monotherapy is more effective for decreasing proteinuria than low-dose ARB monotherapy or CCBs. Although the ARB valsartan has been shown to prevent coronary restenosis in a clinical study (Val-PREST [Valsartan for prevention of restenosis after stenting of type B2/C lesions]), it is still unclear whether ARBs help to prevent restenosis. The results reported by Peters in this issue highlight the relative efficacies of low- (80 mg/day) and high-dose valsartan (160-320 mg/day) for the prevention of in-stent restenosis after the implantation of bare-metal stents, and suggest that high-dose valsartan can reduce the in-stent restenosis rate, target lesion revascularization and target vessel revascularization rates, late lumen loss, and major adverse cardiac events rate more effectively than low-dose valsartan. A better understanding of the differences in the efficacies of high- and low-dose ARBs could be useful in the treatment of patients with cardiovascular disease and may resolve the issue of whether ARBs prevent coronary restenosis. Clinical benefits may be induced by complete blockade of the renin-angiotensin system using high-dose ARB monotherapy. Therefore, physicians need to select a strategy carefully; i.e. either high-dose ARB monotherapy or combination therapy.

Serum nitric oxide metabolite (NO(x)) levels in hypertensive patients at rest: a comparison of age, gender, blood pressure and complications using normotensive controls

1. Hypertensive patients have pathophysiological changes such as atherosclerosis, endothelial dysfunction and inflammations. The patients' serum nitric oxide metabolite (nitrate/nitrite; NO(x)) levels were measured in peripheral blood using normotensive controls for comparison. 2. The NO(x) levels in 175 hypertensive patients with or without comorbid diseases (aged 37-95 years; average 50.6 +/- 0.8 years) were compared with those in 80 normotensive controls (aged 25-73 years; average 37.1 +/- 1.8 years). 3. The NO(x) levels increased with age in both the normotensive and hypertensive women, but not in men. No difference was noted in the NO(x) levels between the normotensive and hypertensive patients without comorbid diseases. The mean value of NO(x) in male hypertensive patients aged under 50 years was close to that of female patients aged 51-60 years. Hypertensive males aged 61-70 years showed almost the same NO(x) levels as those of female patients aged over 81 years. A male group of hypertensive patients with diabetes, hyperlipaemia and renal disorder had a significantly higher NO(x) level compared with a normotensive control group. However, in female groups, only hypertensive patients with hyperlipaemia showed higher serum NO(x) values compared with the normotensive group. 4. These findings suggest that: (i) the occurrence of NO(x) in the serum is not solely the outcome of high blood pressure; (ii) higher serum NO(x) levels in older women are because of an oestrogen deficiency-induced cardiovascular disease; (iii) ageing effects on the circulation system are more apparent in men than in women; and (iv) measurement of NO(x) levels in the serum is helpful for understanding the pathological progress in male hypertensive patients with diseases such as diabetes mellitus, hyperlipaemia and renal disorder.

Improvement of blood pressure control in hypertensive patients with renal diseases

For hypertensive patients with renal diseases (RD), strict blood pressure (BP) control has been recommended in recent hypertension guidelines, such as JNC VI, JNC 7, WHO/ISH 1999 and ESH-ESC 2003. We assessed the current status of BP control and the changes of BP control before and after the publication of these guidelines in 489 hypertensive patients with or without RD (age, 19-89 years, mean 59+/-13 years) who visited the hypertension and kidney outpatient clinic at Kyushu University Hospital. The clinical characteristics of RD and non-RD patients were assessed (RD patients: age, 20-89 years, mean 60+/-13 years, n=311; non-RD patients: age, 19-86 years, mean 58+/-13 years, n=178). In addition, we compared the BP control status in 2003 to that in 1996. In 2003, the BP in RD patients was 134+/-16/78+/-10 mmHg and that in non-RD patients was 138+/-12/83+/-9 mmHg. When strict BP control was defined as <130/80 mmHg, the frequency of strict BP control in RD patients was 28.9% in 2003. In addition, the BP levels of RD patients in 2003 were significantly lower than those in 1996 (134+/-16/78+/-10 mmHg vs. 141+/-17/85+/-10 mmHg, p<0.05 for both systolic blood pressure [SBP] and diastolic blood pressure [DBP]), and the frequency of strict BP control in RD patients was higher in 2003 than in 1996 (28.9% vs. 11.8%, p<0.01). The BP levels of non-RD patients in 2003 tended to be lower than those in 1996 (138+/-12/83+/-9 mmHg vs. 141+/-13/85+/-9 mmHg, n.s.). In 2003, angiotensin II receptor blockers (ARBs) were more frequently prescribed to RD patients than to non-RD patients. Furthermore, the use of ARBs was markedly increased in 2003 compared with 1996. In conclusion, in our outpatient clinic, BP levels in hypertensive patients with RD have improved in recent years, and were lower than those in hypertensive patients without RD, which may in part reflect the physicians' awareness of the importance of strict BP control in RD patients, as suggested by several recent hypertension guidelines.

Do all angiotensin II type 1 receptor blockers have the same beneficial effects?

Angiotensin II type 1 (AT(1)) receptor blockers (ARBs) are highly selective for the AT(1) receptor, which is a member of the G protein-coupled receptor superfamily (GPCRs), and block the diverse effects (hypertension, hypertrophy, heart failure, proteinuria etc.) of angiotensin II. Many ARBs are in clinical use and have been shown to be safe and effective. Over the past several years, reports have discussed the different degrees of the beneficial effects of ARBs. As ARBs do not all have the same effects, the benefits conferred by ARBs may not be class effects. These different effects may be due to differences in the molecular characteristics of ARBs. The results reported by Le et al. in this issue highlight the different characteristics of two ARBs, olmesartan and telmisartan, and suggest that the higher degree of insurmountability, slower dissociation, and higher affinity of olmesartan compared to telmisartan for AT(1) receptors may help it to form a tight binding complex with this receptor. A better understanding of the different molecular mechanisms for each ARB could be useful for the treatment of patients.

Do valsartan and losartan have the same effects in the treatment of coronary artery disease?

BACKGROUND

Many angiotensin II type 1 receptor blockers (ARBs) are available for clinical use, but because they do not all have the same effects, the present study investigated whether all benefits conferred by ARBs are class effects.

METHODS AND RESULTS

Study 1 was a case-control study of patients with coronary artery disease, which showed that a non-depressor dose of valsartan significantly decreased the rate of target lesion revascularization at 6 months after stenting compared with the control group without ARB treatment. In Study 2, 44 patients with acute myocardial infarction who randomly received an initial lower dose of either valsartan or losartan after stenting were evaluated. The late loss and decrease in %diameter stenosis in the valsartan group were significantly lower than those in the losartan group as assessed by quantitative coronary angiography after 6 months. In addition, the valsartan group showed a significantly lower expression of intracellular adhesion molecule-1 and L-selectin.

CONCLUSION

A non-depressor dose of ARB may have beneficial effects on coronary restenosis that are associated with the regulation of adhesion molecules, and these effects might not be a class effect of ARBs.

Effects of Angiotensin II Type 1 Receptor Blockade on the Systemic Blood Nitric Oxide Dynamics in N.OMEGA.-Nitro-L-Arginine Methyl Ester-Treated Rats

We previously succeeded in measuring the nitrosylhemoglobin (HbNO) level as an index of blood nitric oxide (NO) by the electron paramagnetic resonance (EPR) HbNO signal subtraction method. In this study, we examined the effects of olmesartan, an angiotensin II type 1 receptor blocker (ARB), on NO dynamics in N(omega)-nitro-L-arginine methyl ester (L-NAME)-treated rats by the EPR-subtraction method. Oral administration of L-NAME for 2 weeks induced serious hypertension, and the HbNO concentration was reduced to 37.6% of the level in controls. Coadministration of olmesartan improved hypertension and increased the blood HbNO concentration of L-NAME-treated rats. In contrast, coadministration of hydralazine improved hypertension but did not affect the blood HbNO concentration. In conclusion, our findings suggested that chronic administration of olmesartan ameliorated the endothelial dysfunction in L-NAME-treated rats.

Stabilization and regression of albuminuria in Chinese patients with type 2 diabetes: a one-year randomized study of valsartan versus enalapril

This study was designed to compare the short-term (1-y) tolerability and antiproteinuric efficacy of enalapril and valsartan in patients with type 2 diabetes. Forty-two patients with normal renal function or early-stage nephropathy were recruited in Hong Kong and randomized to valsartan 80 mg/day or enalapril 5 mg/day; the doses were increased to 160 mg and 10 mg daily, respectively, as tolerated. Early-morning urine was analyzed for albumin and creatinine and 24-hour urinary albumin excretion at baseline and 1 year after therapy began. Twenty-two patients were randomized to valsartan and 20 to enalapril. The 2 treatment groups were similar in terms of age, sex distribution, and duration of diabetes or hypertension. Blood pressure decreased to a similar extent (-2.5% to -5.0%) with each drug. Similarly, the 24-hour urinary albumin excretion decreased by 5% to 6% with each drug. The albumin-creatinine ratio in early-morning urine samples and plasma creatinine levels decreased in the valsartan group and increased in the enalapril group, but the difference was not significant. Plasma potassium levels were stable in both groups at the end of study. Cough was reported by 7 (35%) patients receiving enalapril and none of those receiving valsartan (P=.003). In conclusion, enalapril and valsartan both reduced blood pressure and albuminuria to a similar extent with 1 year of therapy in Chinese patients with type 2 diabetes and normal renal function or early-stage nephropathy. Fewer adverse events were reported with valsartan, but both drugs appear to be relatively safe.