Seiji Umemoto

Prevention of cardiovascular events with calcium channel blocker-based combination therapies in patients with hypertension: A randomized controlled trial

Objectives Current guidelines recommend the use of multiple medications for hypertension. The present study was aimed at determining which combination was optimal to prevent cardiovascular events. Methods We conducted a prospective, randomized, open-label, blinded-endpoint trial. Hypertensive outpatients aged between 40 and 85 years who did not achieve target blood pressure (BP<140/90 mmHg) with calcium channel blocker (CCB) benidipine 4 mg/day were randomly assigned to receive angiotensin receptor blocker (ARB), &bgr;-blocker, or thiazide diuretic in addition to benidipine. Results Among a total of 3501 patients (1167, benidipine-ARB; 1166, benidipine-&bgr;-blocker; and 1168, benidipine-thiazide), 3293 patients (1110, 1089, and 1094, respectively) who received each combination treatment were included in the analysis. Median follow-up was 3.61 years. At the end of the treatment, 64.1, 66.9, and 66.0% of patients in the benidipine-ARB, benidipine-&bgr;-blocker, and benidipine-thiazide groups achieved target BP, respectively. The cardiovascular composite endpoint occurred in 41 (3.7%), 48 (4.4%), and 32 (2.9%) patients, respectively: the hazard ratio was 1.26 in the benidipine-ARB (P = 0.3505) and 1.54 in the benidipine-&bgr;-blocker (P = 0.0567) groups compared with the benidipine-thiazide group. The secondary analyses revealed that benidipine and thiazide diuretic significantly reduced the incidence of fatal or nonfatal strokes (P = 0.0109) and benidipine and ARB significantly reduced new-onset diabetes (P = 0.0240) compared with benidipine and &bgr;-blocker. All trial treatments were safe and well tolerated. Conclusion CCB combined with ARB, &bgr;-blocker, or thiazide diuretic was similarly effective for the prevention of cardiovascular events and the achievement of target BP.

Importance of NAD(P)H Oxidase–Mediated Oxidative Stress and Contractile Type Smooth Muscle Myosin Heavy Chain SM2 at the Early Stage of Atherosclerosis

Background—Increased vascular oxidative stress induced by hyperlipidemia may alter the phenotype of vascular smooth muscle (SM) cells and play a crucial role in the progression of atherosclerosis. To clarify the mechanisms underlying vascular dysfunction and oxidative stress in hypercholesterolemia, we compared the effects of antioxidant probucol with those of pravastatin on aortic stiffness, phenotypic modulation, oxidative stress, and NAD(P)H oxidase essential subunit p22phox expression in aortic medial SM cells of cholesterol-fed rabbits by using color image analysis of immunostained sections. Methods and Results—Japanese white male rabbits were fed either normal chow or 1% cholesterol diet for 14 weeks. After the first 7 weeks, cholesterol-fed rabbits were further divided into 3 groups: those fed with cholesterol feed only and those additionally given pravastatin (10 mg/d) or probucol (1.3 g/d) for the last 7 weeks. Within 7 weeks of treatment, probucol improved aortic stiffness more effectively than did pravastatin, inhibiting phenotypic modulation by selectively upregulating contractile-type SM myosin heavy chain isoform SM2 and by reducing both p22phox and superoxide content in medial SM cells of cholesterol-fed rabbit aorta. No significant differences in cholesterol levels, superoxide content, and endothelial NO synthase levels in the intima, aortic morphology and fibrosis, and synthetic-type myosin heavy chain in medial SM cells were observed between the 2 drug-treated groups. Conclusions—These results suggest that oxidative stress and SM2 in medial SM cells might be important factors for vascular dysfunction, and strategies aimed at blocking NAD(P)H oxidase and upregulating SM2 may have therapeutic potential against the progression of atherosclerosis in hypercholesterolemia.

The Combination Therapy of Hypertension to Prevent Cardiovascular Events (COPE) trial: Rationale and design

A number of major clinical trials have demonstrated the clinical benefits of lowering blood pressure and have indicated that a majority of patients with hypertension will require more than one drug to achieve optimal blood pressure control. However, there is little data showing which antihypertensive combination best protects patients from cardiovascular events and which best achieves the target blood pressure with the fewest adverse events. The Combination Therapy of Hypertension to Prevent Cardiovascular Events (COPE) trial is the first large-scale investigator-initiated multicenter study with a prospective, randomized, open, blinded endpoint evaluation (PROBE) design to directly compare cardiovascular mortality and morbidity, incidence of adverse drug reaction, and degree of blood pressure reduction in Japanese hypertensive patients for a combination of angiotensin receptor blockers, β-blockers or thiazide diuretics in addition to a calcium antagonist, benidipine hydrochloride, with a response-dependent dose titration scheme. The COPE trial is being conducted with the cooperation of more than 100 centers and clinics in Japan and involves 3,000 patients, who will be followed for 3 years. Eligible patients are being enrolled from May 2003 until May 2006. Results from the COPE trial should provide new evidence for selecting optimal combination therapies for hypertensive patients.

Angiotensin II Type 1 Receptor Antagonist and Angiotensin-Converting Enzyme Inhibitor Altered the Activation of Cu/Zn-Containing Superoxide Dismutase in the Heart of Stroke-Prone Spontaneously Hypertensive Rats

Although angiotensin II type 1 (AT1) receptor antagonists and angiotensin-converting enzyme (ACE) inhibitors are known to reduce both reactive oxygen species (ROS) generated by activated NAD(P)H oxidase and vascular remodeling in hypertension, the effects of AT1 receptor antagonists or ACE inhibitors on ROS-scavenging enzymes remain unclear. We hypothesized that AT1 receptor antagonists or ACE inhibitors may modulate vascular remodeling via superoxide dismutase (SOD) in hypertension. Male stroke-prone spontaneously hypertensive rats (SHRSP) were treated for 6 weeks with a vehicle, an AT1 receptor antagonist (E4177; 30 mg/kg/day), or an ACE inhibitor (cilazapril; 10 mg/kg/day). We evaluated protein expression using immunoblots, determined SOD activities with a spectrophotometric assay, and measured NAD(P)H oxidase activity by a luminescence assay. The two drugs showed equipotent effects on blood pressure, left ventricular hypertrophy and fibrosis, and endothelial NO synthase in the SHRSP hearts. The wall-to-lumen ratio of the intramyocardial arteries and the NAD(P)H oxidase essential subunit p22phox and its activity were significantly reduced, whereas Cu/Zu-containing SOD (Cu/ZnSOD) expression and activity were significantly increased in the SHRSP hearts. Furthermore, E4177 reduced vascular remodeling more than did cilazapril not only by reducing p22phox expression and NAD(P)H oxidase activity but also by upregulating the Cu/ZnSOD expression and its activity in the SHRSP hearts. Thus, both the AT1 receptor antagonist and the ACE inhibitor inhibited vascular remodeling and reduced ROS in SHRSP via not only a reduction in NAD(P)H oxidase but also an upregulation of Cu/ZnSOD.

Eosinophil counts and plasma fibrinogen in patients with vasospastic angina pectoris

Epidemiologic studies have suggested a relation between white blood cell (WBC) counts and the incidence of coronary heart disease. However, the relation between vasospastic angina pectoris (VAP) and WBC counts remains to be elucidated. To clarify the relation between differential and WBC counts in VAP, we compared the hematologic values, blood chemical values, plasma fibrinogen levels, C-reactive protein levels, and coronary risk factors in patients with spontaneous attacks of VAP (n = 39) with those in patients with stable effort angina pectoris (EAP, n = 35) and in control subjects (n = 19). Patients with VAP were further divided into mild VAP (n = 22) and severe VAP groups (n = 17). There were no differences in the coronary risk factors, body temperature, total WBC counts, and C-reactive protein levels among the control, EAP, mild VAP, and severe VAP groups, except that the high-density lipoprotein cholesterol in the EAP group was significantly lower than that in the control group (p <0.01). In contrast, the eosinophil counts were significantly higher in the severe VAP group than in the other 3 groups (p <0.01). Plasma fibrinogen levels were also significantly higher in the severe VAP group than in the other 3 groups (p <0.05). The follow-up study for differential and WBC counts in patients with VAP (n = 23) demonstrated that, after medical therapy, the eosinophil counts were significantly decreased to the some level as those in the control group (p <0.0001). Thus, the eosinophil counts and plasma fibrinogen levels could predict the severity of VAP. Furthermore, a follow-up study in patients with VAP suggests that coronary vasospasm could result in an increase in eosinophil counts.

Combination therapy for hypertension in the elderly: a sub-analysis of the Combination Therapy of Hypertension to Prevent Cardiovascular Events (COPE) Trial.

The Combination Therapy of Hypertension to Prevent Cardiovascular Events (COPE) trial demonstrated that the calcium-channel blocker benidipine-based combination therapies with an angiotensin-receptor blocker (ARB), a β-blocker, or a thiazide diuretic (thiazide) were similarly effective in preventing cardiovascular events and achieving the target blood pressure (BP; <140/90 mm Hg). We further evaluated the efficacy and safety of these combination therapies in older (⩾65 years) and younger (<65 years) hypertensive patients. In this sub-analysis of the COPE trial 3293 patients (1533⩾65 years old and 1760 <65 years old) were randomly assigned to receive benidipine-based therapy with an ARB, a β-blocker or a thiazide. In each group, the average BP did not differ among the three treatment groups. The incidence of the primary cardiovascular composite end point in the older group was higher than in the younger group (12.7 vs. 8.3 per 1000 person-years, P=0.023). The primary composite cardiovascular end point, achievement (%) of target BP, and cardiovascular hard composite end points were similar among the three treatment groups. However, the hazard ratios and 95% confidence intervals in older patients were 2.74 (1.08–6.96; β-blocker vs. thiazide, P=0.022) for fatal and non-fatal stroke, and 2.47 (1.03–5.91; β-blocker vs. ARB, P=0.043) for new-onset diabetes. Thus, benidipine combined with an ARB, a β-blocker, or a thiazide was similarly effective in preventing cardiovascular events and achieving the target BP in both older and younger hypertensive patients. Further studies will be necessary to evaluate the usefulness of benidipine combined with a β-blocker in terms of the incidence of stroke and new-onset diabetes in older patients.

TLR4 is a critical regulator of angiotensin II-induced vascular remodeling: the roles of extracellular SOD and NADPH oxidase

Toll-like receptor 4 (TLR4) and angiotensin II (AngII) induce vascular remodeling through the production of reactive oxygen species (ROS). AngII has also been shown to increase antioxidant enzyme extracellular superoxide dismutase (ecSOD). However, the roles of TLR4 in Ang II-induced ROS production, vascular remodeling and hypertension remain unknown. Mice lacking TLR4 function showed significant inhibition of vascular remodeling in response to chronic AngII infusion, with no impact on blood pressure. The increases in ROS level and NADPH oxidase activity in response to AngII infusion were markedly blunted in TLR4-deficient mice. Similar effects were observed in wild-type (WT) mice treated with a sub-depressor dose of the AT1 receptor antagonist irbesartan, which had no effects on TLR4-deficient mice. Intriguingly, the AngII infusion-induced increases in ecSOD activity and expression were rather enhanced in TLR4-deficient mice compared with WT mice, whereas the expression of the proinflammatory chemokine MCP-1 was decreased. Importantly, AngII-induced vascular remodeling was positively correlated with NADPH oxidase activity, ROS levels and MCP-1 expression levels. Notably, chronic norepinephrine infusion, which elevates blood pressure without increasing ROS production, did not induce significant vascular remodeling in WT mice. Taken together, these findings suggest that ROS elevation is required for accelerating vascular remodeling but not for hypertensive effects in this model. We demonstrated that TLR4 plays a pivotal role in regulating AngII-induced vascular ROS levels by inhibiting the expression and activity of the antioxidant enzyme ecSOD, as well as by activating NADPH oxidase, which enhances inflammation to facilitate the progression of vascular remodeling.

Combination therapy for hypertension in patients with CKD: a subanalysis of the Combination Therapy of Hypertension to Prevent Cardiovascular Events trial.

The Combination Therapy of Hypertension to Prevent Cardiovascular Events (COPE) trial was a multicenter, randomized, three-arm comparative study (N=3293) undertaken to determine the optimal combination therapy, based on the occurrence of cardiovascular events in patients treated with an angiotensin II receptor blocker (ARB), a β-blocker (BB) or a thiazide diuretic (TD) in addition to the calcium antagonist benidipine as baseline medication. This subanalysis was conducted to compare the efficacy of three combination therapies in a subset of 834 patients with chronic kidney disease (CKD) (287 patients treated with benidpine-ARB, 283 patients treated with benidipine-BB and 264 patients treated with benidipine-TD). The incidence of composite cardiovascular events as the primary end point did not differ among these three groups. The incidence of hard end points and cerebrovascular events among these groups did not differ either, although the incidence among all patients in the COPE trial was lower in the benidipine-TD group than in the benidipine-BB group. The incidence of new-onset diabetes mellitus was higher in the benidipine-TD group than in the benidipine-ARB group among patients with CKD. The estimated glomerular filtration rate (eGFR) was maintained even after 12 months of treatment in patients with a baseline eGFR <60 ml min−1 per 1.73 m2 regardless of the treatment group, although the eGFR decreased over time in all patients in the three groups. In conclusion, in patients with CKD, all of the tested combination therapies demonstrated comparable efficacy in terms of prevention of cardiovascular events as well as maintenance of eGFR.

Angiotensin II Type 1 Receptor Antagonist Downregulates Nonmuscle Myosin Heavy Chains in Spontaneously Hypertensive Rat Aorta

The aim of this study was to clarify the differences between the angiotensin II type 1 (AT1) receptor antagonist and the angiotensin-converting enzyme (ACE) inhibitor on smooth muscle and nonmuscle myosin heavy chain isoforms in aortic smooth muscle cells of Wistar-Kyoto rats and spontaneously hypertensive rats. All 4 myosin heavy chain isoforms are heterogeneously expressed in the smooth muscle cells of the aortic tunica media in 20-week-old rats, and the contractile-type myosin heavy chains are highly expressed in smooth muscle cells of the aortic tunica media compared with the synthetic-type myosin heavy chains. Both the AT1 receptor antagonist and the ACE inhibitor had the same effects on hemodynamics, smooth muscle cell hypertrophy and proliferation, fibrosis, and vascular remodeling in spontaneously hypertensive rats. However, the AT1 receptor antagonist had a more potent effect on the downregulation of the synthetic-type myosin heavy chains than the ACE inhibitor in spontaneously hypertensive rat aortic tunica media. In contrast, these effects of the AT1 receptor antagonist and the ACE inhibitor on hemodynamics, morphology, fibrosis, and expression of myosin heavy chain isoforms in smooth muscle cells of the aortic tunica media were not observed in Wistar-Kyoto rats. Thus, within 6 weeks, the AT1 receptor antagonist might modulate the cellular composition of myosin heavy chain isoforms in smooth muscle cells more efficiently than the ACE inhibitor, without morphological changes in the spontaneously hypertensive rat aorta.

Up-regulation of Akt and eNOS induces vascular smooth muscle cell differentiation in hypertension in vivo.

Recent studies have shown that angiotensin II type 1 (AT1) receptor-mediated Akt activation induces vascular smooth muscle cell (VSMC) dedifferentiation in vitro. However, the critical signal transductions affecting the VSMC phenotype remain unclear in vivo. We examined whether signal transduction through AT1 receptor-mediated reactive oxygen species (ROS) could regulate the VSMC phenotype in stroke-prone spontaneously hypertensive rats (SHRSPs). Male SHRSPs were randomized and treated for 6 weeks with a vehicle, an ACE inhibitor cilazapril, or an AT1 receptor antagonist E4177. The 2 drugs showed equipotent effects on the blood pressure, aortic morphology, and collagen deposition. Both drugs also significantly reduced aortic NAD(P)H oxidase activity and p38MAPK and ERK expression, whereas p-Akt, eNOS, and SM2 were significantly increased in SHRSP aortas. Furthermore, E4177 was more effective than cilazapril at inducing VSMC differentiation by reducing NAD(P)H oxidase activity, and up-regulating p-Akt, eNOS, and SM2. Thus, an ACE inhibitor and an AT1 receptor antagonist inhibited VSMC dedifferentiation through inhibition of NAD(P)H oxidase activity and up-regulation of eNOS and Akt in SHRSP aortas, suggesting that in contrast to the in vitro experiments, AT1 receptor-mediated NAD(P)H oxidase-generated ROS, eNOS, and Akt might be crucial determinants for the VSMC phenotype in hypertension in vivo.