RNA Interference With Zilebesiran for Mild to Moderate Hypertension: The KARDIA-1 Randomized Clinical Trial.

Importance: Angiotensinogen is the most upstream precursor of the renin-angiotensin-aldosterone system, a key pathway in blood pressure (BP) regulation. Zilebesiran, an investigational RNA interference therapeutic, targets hepatic angiotensinogen synthesis. Objective: To evaluate antihypertensive efficacy and safety of different zilebesiran dosing regimens. Design, Setting, and Participants: This phase 2, randomized, double-blind, dose-ranging study of zilebesiran vs placebo was performed at 78 sites across 4 countries. Screening initiation occurred in July 2021 and the last patient visit of the 6-month study occurred in June 2023. Adults with mild to moderate hypertension, defined as daytime mean ambulatory systolic BP (SBP) of 135 to 160 mm Hg following antihypertensive washout, were randomized. Interventions: Randomization to 1 of 4 subcutaneous zilebesiran regimens (150, 300, or 600 mg once every 6 months or 300 mg once every 3 months) or placebo (once every 3 months) for 6 months. Main Outcomes and Measures: The primary end point was between-group difference in least-squares mean (LSM) change from baseline to month 3 in 24-hour mean ambulatory SBP. Results: Of 394 randomized patients, 377 (302 receiving zilebesiran and 75 receiving placebo) comprised the full analysis set (93 Black patients [24.7%]; 167 [44.3%] women; mean [SD] age, 57 [11] years). At 3 months, 24-hour mean ambulatory SBP changes from baseline were -7.3 mm Hg (95% CI, -10.3 to -4.4) with zilebesiran, 150 mg, once every 6 months; -10.0 mm Hg (95% CI, -12.0 to -7.9) with zilebesiran, 300 mg, once every 3 months or every 6 months; -8.9 mm Hg (95% CI, -11.9 to -6.0) with zilebesiran, 600 mg, once every 6 months; and 6.8 mm Hg (95% CI, 3.6-9.9) with placebo. LSM differences vs placebo in change from baseline to month 3 were -14.1 mm Hg (95% CI, -19.2 to -9.0; P < .001) with zilebesiran, 150 mg, once every 6 months; -16.7 mm Hg (95% CI, -21.2 to -12.3; P < .001) with zilebesiran, 300 mg, once every 3 months or every 6 months; and -15.7 mm Hg (95% CI, -20.8 to -10.6; P < .001) with zilebesiran, 600 mg, once every 6 months. Over 6 months, 60.9% of patients receiving zilebesiran had adverse events vs 50.7% patients receiving placebo and 3.6% had serious adverse events vs 6.7% receiving placebo. Nonserious drug-related adverse events occurred in 16.9% of zilebesiran-treated patients (principally injection site reactions and mild hyperkalemia) and 8.0% of placebo-treated patients. Conclusions and Relevance: In adults with mild to moderate hypertension, treatment with zilebesiran across a range of doses at 3-month or 6-month intervals significantly reduced 24-hour mean ambulatory SBP at month 3. Trial Registration: ClinicalTrials.gov Identifier: NCT04936035.

Prospective ARNI vs. ACE inhibitor trial to DetermIne Superiority in reducing heart failure Events after Myocardial Infarction (PARADISE-MI): design and baseline characteristics.

AIMS: Patients surviving an acute myocardial infarction (AMI) are at risk of developing symptomatic heart failure (HF) or premature death. We hypothesized that sacubitril/valsartan, effective in the treatment of chronic HF, prevents development of HF and reduces cardiovascular death following high-risk AMI compared to a proven angiotensin-converting enzyme (ACE) inhibitor. This paper describes the study design and baseline characteristics of patients enrolled in the Prospective ARNI vs. ACE inhibitor trial to DetermIne Superiority in reducing heart failure Events after Myocardial Infarction (PARADISE-MI) trial. METHODS AND RESULTS: PARADISE-MI, a multinational (41 countries), double-blind, active-controlled trial, randomized patients within 0.5-7 days of presentation with index AMI to sacubitril/valsartan or ramipril. Transient pulmonary congestion and/or left ventricular ejection fraction (LVEF) ≤40% and at least one additional factor augmenting risk of HF or death (age ≥70 years, estimated glomerular filtration rate <60 mL/min/1.73 m2 , diabetes, prior myocardial infarction, atrial fibrillation, LVEF <30%, Killip class ≥III, ST-elevation myocardial infarction without reperfusion) were required for inclusion. PARADISE-MI was event-driven targeting 708 primary endpoints (cardiovascular death, HF hospitalization or outpatient development of HF). Randomization of 5669 patients occurred 4.3 ± 1.8 days from presentation with index AMI. The mean age was 64 ± 12 years, 24% were women. The majority (76%) qualified with ST-segment elevation myocardial infarction; acute percutaneous coronary intervention was performed in 88% and thrombolysis in 6%. LVEF was 37 ± 9% and 58% were in Killip class ≥II. CONCLUSIONS: Baseline therapies in PARADISE-MI reflect advances in contemporary evidence-based care. With enrollment complete PARADISE-MI is poised to determine whether sacubitril/valsartan is more effective than a proven ACE inhibitor in preventing development of HF and cardiovascular death following AMI.

Efficacy and Safety of Sacubitril/Valsartan in Japanese Patients With Chronic Heart Failure and Reduced Ejection Fraction　- Results From the PARALLEL-HF Study.

BACKGROUND: In the Prospective Comparison of angiotensin receptor neprilysin inhibitor (ARNI) With ACEi to Determine Impact on Global Mortality and Morbidity in Heart Failure (PARADIGM-HF) study, treatment with sacubitril/valsartan reduced the primary outcome of cardiovascular (CV) death and heart failure (HF) hospitalization compared with enalapril in patients with chronic HF and reduced ejection fraction (HFrEF). A prospective randomized trial was conducted to assess the efficacy and safety of sacubitril/valsartan in Japanese HFrEF patients.Methods and Results:In the Prospective comparison of ARNI with ACEi to determine the noveL beneficiaL trEatment vaLue in Japanese Heart Failure patients (PARALLEL-HF) study, 225 Japanese HFrEF patients (New York Heart Association [NYHA] class II-IV, left ventricular ejection fraction [LVEF] ≤35%) were randomized (1 : 1) to receive sacubitril/valsartan 200 mg bid or enalapril 10 mg bid. Over a median follow up of 33.9 months, no significant between-group difference was observed for the primary composite outcome of CV death and HF hospitalization (HR 1.09; 95% CI 0.65-1.82; P=0.6260). Early and sustained reductions in N-terminal pro-brain natriuretic peptide (NT-proBNP) from baseline were observed with sacubitril/valsartan compared with enalapril (between-group difference: Week 2: 25.7%, P<0.01; Month 6: 18.9%, P=0.01, favoring sacubitril/valsartan). There was no significant difference in the changes in NYHA class and Kansas City Cardiomyopathy Questionnaire (KCCQ) clinical summary score at Week 8 and Month 6. Sacubitril/valsartan was well tolerated with fewer study drug discontinuations due to adverse events, although the sacubitril/valsartan group had a higher proportion of patients with hypotension. CONCLUSIONS: In Japanese patients with HFrEF, there was no difference in reduction in the risk of CV death or HF hospitalization between sacubitril/valsartan and enalapril, and sacubitril/valsartan was safe and well tolerated.

Efficacy and safety of sacubitril/valsartan compared with olmesartan in Asian patients with essential hypertension: A randomized, double-blind, 8-week study.

This study assessed the efficacy and safety of angiotensin receptor neprilysin inhibitor sacubitril/valsartan vs olmesartan in Asian patients with mild-to-moderate hypertension. Patients (N = 1438; mean age, 57.7 years) with mild-to-moderate hypertension were randomized to receive once daily administration of sacubitril/valsartan 200 mg (n = 479), sacubitril/valsartan 400 mg (n = 473), or olmesartan 20 mg (n = 486) for 8 weeks. The primary endpoint was reduction in mean sitting systolic blood pressure (msSBP) from baseline with sacubitril/valsartan 200 mg vs olmesartan 20 mg at Week 8. Secondary endpoints included msSBP reduction with sacubitril/valsartan 400 mg, and reductions in clinic and ambulatory BP and pulse pressure (PP) vs olmesartan. In addition, changes in msBP from baseline in the Chinese subpopulation, elderly (≥65 years), and in patients with isolated systolic hypertension (ISH) were assessed. Sacubitril/valsartan 200 mg provided a significantly greater reduction in msSBP than olmesartan 20 mg at Week 8 (between-treatment difference: -2.33 mm Hg [95% confidence interval (CI) -4.00 to -0.66 mm Hg], P < 0.05 for non-inferiority and superiority). Greater reductions in msSBP were also observed with sacubitril/valsartan 400 mg vs olmesartan 20 mg (-3.52 [-5.19 to -1.84 mm Hg], P < 0.001 for superiority). Similarly, greater reductions in msBP were observed in the Chinese subpopulation, in elderly patients, and those with ISH. In addition, both doses of sacubitril/valsartan provided significantly greater reductions from baseline in nighttime mean ambulatory BP vs olmesartan. Treatment with sacubitril/valsartan 200 or 400 mg once daily is effective and provided superior BP reduction than olmesartan 20 mg in Asian patients with mild-to-moderate hypertension and is generally safe and well tolerated.

Angiotensin Receptor Neprilysin Inhibitor in Japanese Patients With Heart Failure and Reduced Ejection Fraction　- Baseline Characteristics and Treatment of PARALLEL-HF Trial.

BACKGROUND: The objective of the present analyses was to describe the baseline characteristics and treatment of the Japanese patients with HFrEF in THE PARALLEL-HF study. Methods and Results: Key demographic, clinical and laboratory findings, along with treatment, were reported and compared with patients enrolled in the PARADIGM-HF trial and other contemporary randomized clinical trials and registries of Japanese patients with HFrEF. In addition, the MAGGIC and EMPHASIS-HF risk scores were calculated. A total of 225 Japanese patients were randomized in PARALLEL-HF with a mean age of 67.9 years and the majority of the patients being male (85.8%) and in NYHA Class II (93.8%). Key baseline characteristics in PARALLEL-HF were generally comparable with PARADIGM-HF, and other contemporary clinical trials and registries of Japanese HFrEF patients. Patients enrolled in PARALLEL-HF were well treated with conventional evidence-based therapy at baseline (angiotensin-converting enzyme inhibitor inhibitor/angiotensin receptor blocker, 62.7%/37.3%; ß-blockers, 94.7%; mineralocorticoid receptor antagonist, 59.1%). Despite the evidence-based treatment and most patients being in NYHA Class II, these patients had a low LVEF (mean 28.1%) and were at high risk of cardiovascular mortality and morbidity as assessed by the MAGGIC and EMPHASIS-HF risk scores. CONCLUSIONS: Overall, the patients in PARALLEL-HF were largely representative of contemporary ambulatory patients with HFrEF who are well treated with evidence-based therapies. PARALLEL-HF will determine whether sacubitril/valsartan provides similar improvements in clinical outcomes in Japanese HFrEF patients as observed in the PARADIGM-HF study.

Effects of Sacubitril/Valsartan Versus Olmesartan on Central Hemodynamics in the Elderly With Systolic Hypertension: The PARAMETER Study.

Effective treatment of systolic hypertension in elderly patients remains a major therapeutic challenge. A multicenter, double-blind, randomized controlled trial with sacubitril/valsartan (LCZ696), a first-in-class angiotensin receptor neprilysin inhibitor, was conducted to determine its effects versus olmesartan (angiotensin receptor blocker) on central aortic pressures, in elderly patients (aged ≥60 years) with systolic hypertension and pulse pressure >60 mm Hg, indicative of arterial stiffness. Patients (n=454; mean age, 67.7 years; mean seated systolic blood pressure, 158.6 mm Hg; mean seated pulse pressure, 69.7 mm Hg) were randomized to receive once-daily sacubitril/valsartan 200 mg or olmesartan 20 mg, force titrated to double the initial doses after 4 weeks, before primary assessment at 12 weeks. The study extended double-blind treatment for 12 to 52 weeks, during which amlodipine (2.5-5 mg) and subsequently hydrochlorothiazide (6.25-25 mg) were added-on for patients not achieving blood pressure target (<140/90). At week 12, sacubitril/valsartan reduced central aortic systolic pressure (primary assessment) greater than olmesartan by -3.7 mm Hg (P=0.010), further corroborated by secondary assessments at week 12 (central aortic pulse pressure, -2.4 mm Hg, P<0.012; mean 24-hour ambulatory brachial systolic blood pressure and central aortic systolic pressure, -4.1 mm Hg and -3.6 mm Hg, respectively, both P<0.001). Differences in 24-hour ambulatory pressures were pronounced during sleep. After 52 weeks, blood pressure parameters were similar between treatments (P<0.002); however, more patients required add-on antihypertensive therapy with olmesartan (47%) versus sacubitril/valsartan (32%; P<0.002). Both treatments were equally well tolerated. The PARAMETER study (Prospective Comparison of Angiotensin Receptor Neprilysin Inhibitor With Angiotensin Receptor Blocker Measuring Arterial Stiffness in the Elderly), for the first time, demonstrated superiority of sacubitril/valsartan versus olmesartan in reducing clinic and ambulatory central aortic and brachial pressures in elderly patients with systolic hypertension and stiff arteries.

Efficacy and safety of sacubitril/valsartan (LCZ696) in Japanese patients with chronic heart failure and reduced ejection fraction: Rationale for and design of the randomized, double-blind PARALLEL-HF study.

BACKGROUND: The prognosis of heart failure patients with reduced ejection fraction (HFrEF) in Japan remains poor, although there is growing evidence for increasing use of evidence-based pharmacotherapies in Japanese real-world HF registries. Sacubitril/valsartan (LCZ696) is a first-in-class angiotensin receptor neprilysin inhibitor shown to reduce mortality and morbidity in the recently completed largest outcome trial in patients with HFrEF (PARADIGM-HF trial). The prospectively designed phase III PARALLEL-HF (Prospective comparison of ARNI with ACE inhibitor to determine the noveL beneficiaL trEatment vaLue in Japanese Heart Failure patients) study aims to assess the clinical efficacy and safety of LCZ696 in Japanese HFrEF patients, and show similar improvements in clinical outcomes as the PARADIGM-HF study enabling the registration of LCZ696 in Japan. METHODS AND DESIGN: This is a multicenter, randomized, double-blind, parallel-group, active controlled study of 220 Japanese HFrEF patients. Eligibility criteria include a diagnosis of chronic HF (New York Heart Association Class II-IV) and reduced ejection fraction (left ventricular ejection fraction ≤35%) and increased plasma concentrations of natriuretic peptides [N-terminal pro B-type natriuretic peptide (NT-proBNP) ≥600pg/mL, or NT-proBNP ≥400pg/mL for those who had a hospitalization for HF within the last 12 months] at the screening visit. The study consists of three phases: (i) screening, (ii) single-blind active LCZ696 run-in, and (iii) double-blind randomized treatment. Patients tolerating LCZ696 50mg bid during the treatment run-in are randomized (1:1) to receive LCZ696 100mg bid or enalapril 5mg bid for 4 weeks followed by up-titration to target doses of LCZ696 200mg bid or enalapril 10mg bid in a double-blind manner. The primary outcome is the composite of cardiovascular death or HF hospitalization and the study is an event-driven trial. CONCLUSIONS: The design of the PARALLEL-HF study is aligned with the PARADIGM-HF study and aims to assess the efficacy and safety of LCZ696 in Japanese HFrEF patients.

Effects of a novel aldosterone synthase inhibitor for treatment of primary hypertension: results of a randomized, double-blind, placebo- and active-controlled phase 2 trial.

BACKGROUND: LCI699, a novel inhibitor of aldosterone synthase, reduces serum aldosterone, and may have benefit in the treatment of hypertension. METHODS AND RESULTS: We performed the first double-blind, randomized trial with LCI699 in patients with primary hypertension. We randomized 524 patients to LCI699 0.25 mg once daily (n=92), 0.5 mg once daily (n=88), 1.0 mg once daily (n=86), and 0.5 mg twice daily (n=97); eplerenone 50 mg twice daily (n=84); or placebo (n=77) for 8 weeks. Adrenocorticotropic hormone (250 µg IV) stimulation testing was performed in a subset of patients to quantify the selectivity of LCI699 for aldosterone synthase compared with 11-ß-hydroxylase. Reductions in clinic diastolic blood pressure were significant for LCI699 1.0 mg (-7.1 mm Hg; P=0.0012) and eplerenone 50 mg twice daily (-7.9 mm Hg; P<0.0001) compared with placebo (-2.6 mm Hg) but not other doses of LCI699. Significant reductions in clinic systolic blood pressure were observed with all doses of LCI699 (P<0.005 or better) and eplerenone (P<0.0001). All doses of LCI699 significantly reduced 24-hour ambulatory blood pressure compared with placebo (P<0.01). Adrenocorticotropic hormone stimulation of cortisol was suppressed in ≈20% of subjects receiving LCI699 at a total daily dose of 1.0 mg. Safety and tolerability were similar among LCI699, placebo, and eplerenone. CONCLUSIONS: Aldosterone synthase inhibition with LCI699 significantly lowered clinic and ambulatory blood pressure. A minority of subjects developed blunted adrenocorticotropic hormone-stimulated release of cortisol. These results support additional research to evaluate use of aldosterone synthase inhibition in primary hypertension and/or patients characterized by aldosterone excess. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00758524.

Targeted deletion of Kv4.2 eliminates I(to,f) and results in electrical and molecular remodeling, with no evidence of ventricular hypertrophy or myocardial dysfunction.

Previous studies have demonstrated a role for voltage-gated K+ (Kv) channel alpha subunits of the Kv4 subfamily in the generation of rapidly inactivating/recovering cardiac transient outward K+ current, I(to,f), channels. Biochemical studies suggest that mouse ventricular I(to,f) channels reflect the heteromeric assembly of Kv4.2 and Kv4.3 with the accessory subunits, KChIP2 and Kvbeta1, and that Kv4.2 is the primary determinant of regional differences in (mouse ventricular) I(to,f) densities. Interestingly, the phenotypic consequences of manipulating I(to,f) expression in different mouse models are distinct. In the experiments here, the effects of the targeted deletion of Kv4.2 (Kv4.2(-/-)) were examined. Unexpectedly, voltage-clamp recordings from Kv4.2(-/-) ventricular myocytes revealed that I(to,f) is eliminated. In addition, the slow transient outward K+ current, I(to,s), and the Kv1.4 protein (which encodes I(to,s)) are upregulated in Kv4.2(-/-) ventricles. Although Kv4.3 mRNA/protein expression is not measurably affected, KChIP2 expression is markedly reduced in Kv4.2(-/-) ventricles. Similar to Kv4.3, expression of Kvbeta1, as well as Kv1.5 and Kv2.1, is similar in wild-type and Kv4.2(-/-) ventricles. In addition, and in marked contrast to previous findings in mice expressing a truncated Kv4.2 transgene, the elimination I(to,f) in Kv4.2(-/-) mice does not result in ventricular hypertrophy. Taken together, these findings demonstrate not only an essential role for Kv4.2 in the generation of mouse ventricular I(to,f) channels but also that the loss of I(to,f) per se does not have overt pathophysiological consequences.

KChIP2 modulates the cell surface expression of Kv 1.5-encoded K(+) channels.

The Kv channel interacting proteins (KChIPs) were identified in a yeast two hybrid screen using the N terminus of Kv4.3 as bait. Previous studies have demonstrated that KChIP2 associates with voltage-gated K(+) (Kv) pore-forming (alpha) subunits of the Kv4 subfamily and contributes to the formation of the rapidly inactivating and recovering Kv4-encoded cardiac transient outward K(+) channels, I(to,f). Here, we report that co-expression of KChIP2 (or KChIP1) also modulates the functional cell surface expression of Kv1.5-encoded K(+) channels in transiently transfected HEK-293 cells. In contrast to the effects of KChIP2 on Kv4 channels, however, co-expression of KChIP2 (or KChIP1) decreases Kv1.5-encoded K(+) currents. Although current densities are reduced, KChIP2 (or KChIP1) co-expression does not affect the time- or voltage-dependent properties of heterologously expressed Kv1.5-encoded K(+) currents. Immunohistochemical and cell surface biotinylation experiments demonstrate that KChIP2 reduces the cell surface expression of Kv1.5, likely by inhibiting forward trafficking from the endoplasmic reticulum. In addition, biochemical experiments reveal that KChIP2 co-immunoprecipitates with Kv1.5 (as well as Kv4.2/Kv4.3) from adult mouse ventricles, demonstrating that, similar to other Kv accessory subunits, KChIP2 is a multifunctional Kv channel accessory subunit. Taken together, the results here suggest that KChIP2 contributes to the formation of functional mouse ventricular (Kv1.5-encoded) I(K,slow1) channels as well, perhaps, as other Kv1.5-encoded K(+) currents, including I(Kur) (I(K,ultrarapid)), in human atria.

Clinical experience with perindopril in elderly hypertensive patients: a subgroup analysis of a large community trial.

OBJECTIVE: To evaluate the effectiveness and safety of perindopril in a subgroup of 3010 elderly (> or =65 years) hypertensive patients, who participated in a large US general practice-based community trial. METHODS: All patients received open-label perindopril 4 mg once a day for 6 weeks. After 6 weeks the dosage was either maintained (group I) or increased to 8 mg/day (group II) based on the physician's assessment of blood pressure (BP) response. Patients were then followed for another 6 weeks for a total study duration of 12 weeks. RESULTS: Demographic and baseline clinical characteristics revealed a higher proportion of women, longer duration of hypertension and higher baseline systolic BP (SBP) among elderly than young (<65 years, n = 7332) hypertensive patients. A clinically relevant BP reduction of similar magnitude was obtained in elderly and young patients with perindopril monotherapy. At week 12, the mean reduction in BP from baseline was 18.4/8.7 mm Hg in the elderly and 17.5/11.3 mm Hg in the young. Elderly patients with hypertension not responding adequately to the 4 mg/day dosage at week 6 had a BP reduction of 6.3/3.6 mm Hg (group II). Up-titration to an 8 mg/day dosage for another 6 weeks gave an additional 8.9/3.5 mm Hg reduction resulting in a total reduction of 15.2/7.1 mm Hg from baseline. A similar magnitude of increase in response to up-titration of perindopril was seen in young patients. BP control (<140/90 mm Hg) on perindopril monotherapy was achieved in 41.4% of elderly and 51.9% of young patients. In both age groups, up-titration to an 8.0 mg/day dosage in group II patients increased BP control by approximately 5-fold at week 12 (28.2% in the elderly and 36.4% in the young). A similar increased response on BP reduction and BP control (<140/90 mm Hg) with up-titration was seen in elderly subgroups of African American and diabetic patients. The 7th Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure recommended target goal of <130/80 mm Hg was achieved with perindopril monotherapy in 15.6% of hypertensive diabetic patients. Perindopril reduced BP effectively and safely in very elderly (> or =75 years) hypertensive patients. Perindopril was well tolerated in elderly patients including high-risk groups. The incidence of cough (7-10%), the most common symptom, was similar in all age groups. The low incidence of postural hypotension (< or =0.2%) observed in the elderly and very elderly further supports the good tolerance and safety profile of the drug. Data analysis from this study suggests that community physicians, in general, are less aggressive in controlling BP in the elderly and more inclined to treat or control diastolic BP than SBP. CONCLUSION: Perindopril treatment is effective and well tolerated in elderly patients with hypertension.

Heterogeneous expression of repolarizing, voltage-gated K+ currents in adult mouse ventricles.

Previous studies have documented the expression of four kinetically distinct voltage-gated K(+) (Kv) currents, I(to,f), I(to,s), I(K,slow) and I(ss), in mouse ventricular myocytes and demonstrated that I(to,f) and I(to,s) are differentially expressed in the left ventricular apex and the interventricular septum. The experiments here were undertaken to test the hypothesis that there are further regional differences in the expression of Kv currents or the Kv subunits (Kv4.2, Kv4.3, KChIP2, Kv1.5, Kv2.1) encoding these currents in adult male and female (C57BL6) mouse ventricles. Whole-cell voltage-clamp recordings revealed that mean (+/-s.e.m.) peak outward K(+) current and I(to,f) densities are significantly (P < 0.001) higher in cells isolated from the right (RV) than the left (LV) ventricles. Within the LV, peak outward K(+) current and I(to,f) densities are significantly (P < 0.05) higher in cells from the apex than the base. In addition, I(to,f) and I(K,slow) densities are lower in cells isolated from the endocardial (Endo) than the epicardial (Epi) surface of the LV wall. Importantly, similar to LV apex cells, I(to,s) is not detected in RV, LV base, LV Epi or LV Endo myocytes. No measurable differences in K(+) current densities or properties are evident in RV or LV cells from adult male and female mice, although I(to,f), I(to,s), I(K,slow) and I(ss) densities are significantly (P < 0.01) higher, and action potential durations at 50% (APD(50)) are significantly (P < 0.05) shorter in male septum cells. Western blot analysis revealed that the expression levels of Kv4.2, Kv4.3, KChIP2, Kv1.5 and Kv2.1 are similar in male and female ventricles. In addition, consistent with the similarities in repolarizing Kv current densities, no measurable differences in ECG parameters, including corrected QT (QT(c)) intervals, are detected in telemetric recordings from adult male and female (C57BL6) mice.

Clinical experience with perindopril in patients nonresponsive to previous antihypertensive therapy: a large US community trial.

A subgroup analysis of a large US community trial was conducted to evaluate the antihypertensive efficacy and safety of perindopril, an angiotensin-converting enzyme inhibitor (ACEI), in 3159 patients who lacked blood pressure (BP) control at entry with previous antihypertensive therapy. Patients received 4 mg perindopril daily for 6 weeks. Based on physicians' assessment of BP response, the patients were then either maintained on 4 mg daily (group 1) or the dose was increased to 8 mg daily (group 2) for an additional 6 weeks. The mean baseline sitting BP was 158.2/92.9 mm Hg. Perindopril monotherapy produced a significant BP decrease from baseline of 11.6/6.5 mm Hg and 14.9/8.4 mm Hg at weeks 6 and 12, respectively. In group 1 patients, the majority of BP decrease occurred at week 6 (17.3/9.5 mm Hg) and was maintained until the end of week 12 (18.2/10.1 mm Hg). In group 2 patients, the BP decrease on the 4-mg dose was modest at week 6 by 5.2/3.1 mm Hg. However, further dose up-titration of perindopril to 8 mg resulted in a clinically significant BP decrease of 11.9/6.8 mm Hg from baseline to week 12. Significant antihypertensive effects of perindopril were also demonstrated in the special patient populations of elderly (>or=65 years), black, isolated systolic hypertension, patients with concomitant cardiovascular diseases, and patients nonresponsive to other ACEI therapy. Overall, BP control (<140/<90 mm Hg) was achieved in 40.0% of patients at week 12. Perindopril was well tolerated with cough and angioedema reported in 8.5% and 0.4% patients, respectively. Physicians assessed therapeutic response to perindopril as satisfactory in 73.8% patients who were nonresponsive to previous antihypertensive therapy. These results suggest that, in a community-based practice, perindopril monotherapy (4-8 mg/d) is an effective and safe therapeutic option in patients nonresponsive to previous antihypertensive therapy.

Clinical experience with perindopril in African-American hypertensive patients: a large United States community trial.

BACKGROUND: The prevalence of hypertension is greater in African Americans, and management of this condition presents challenges for practicing physicians. METHODS: The effectiveness and safety of perindopril was evaluated in hypertensive African-American patients (n = 1412) and hypertensive white patients (n = 7745) who had participated in a large United States community trial. Patients received perindopril 4 mg once daily for 6 weeks. Based on physicians' clinical judgment at week 6, the dose was either maintained or increased to 8 mg for an additional 6 weeks. RESULTS: Reduction of blood pressure (BP) was significant with perindopril monotherapy (4 to 8 mg once daily) in African Americans and whites (P <.001). The magnitude of BP reduction was significantly more in whites (P <.001). Up-titration of perindopril achieved additional BP reduction in both ethnic groups (P <.001). Control of BP (<140/90 mm Hg) in elderly (>65 years of age) and diabetic African-Americans subgroups was achieved in 32.1% and 31.6%, respectively. Perindopril was safe and well tolerated. CONCLUSIONS: Perindopril monotherapy is effective and is a viable initial therapeutic option as an antihypertensive agent in African-American individuals with hypertension.

Selective elimination of I(K,slow1) in mouse ventricular myocytes expressing a dominant negative Kv1.5alpha subunit.

Although previous studies have revealed a role for the voltage-gated K+ channel alpha-subunit Kv1.5 (KCNA5) in the generation of the 4-aminopyridine (4-AP)-sensitive component of delayed rectification in mouse ventricles (IK,slow1), the phenotypic consequences of manipulating IK,slow1 expression in vivo in different (mouse) models are distinct. In these experiments, point mutations were introduced in the pore region of Kv1.5 to change the tryptophan (W) at position 461 to phenylalanine (F) to produce a nonconducting subunit, Kv1.5W461F, that is shown to function as a Kv1 subfamily-specific dominant negative (Kv1.5DN). With the use of the alpha-myosin heavy chain promoter to direct cardiac-specific expression, three lines of Kv1.5DN-expressing (C57BL6) transgenic mice were generated and characterized. Electrophysiological recordings from Kv1.5-DN-expressing left ventricular myocytes revealed that the micromolar 4-AP sensitive IK,slow1 is selectively eliminated. The attenuation of IK,slow1 is accompanied by increased ventricular action potential durations and marked QT prolongation. In contrast to previous findings in mice expressing a truncated (DN) Kv1.1 transgene; however, no electrical remodeling is evident in Kv1.5DN-expressing ventricular myocytes, and the (Kv1.5DN-induced) elimination of IK,slow1 does not result in spontaneous ventricular arrhythmias.

Modulation of Kv4-encoded K(+) currents in the mammalian myocardium by neuronal calcium sensor-1.

Voltage-gated K(+) channels are multimeric proteins, consisting of four pore-forming alpha-subunits alone or in association with accessory subunits. Recently, for example, it was shown that the accessory Kv channel interacting proteins form complexes with Kv4 alpha-subunits and modulate Kv4 channel activity. The experiments reported here demonstrate that the neuronal calcium sensor protein-1 (NCS-1), another member of the recoverin-neuronal calcium sensor superfamily, is expressed in adult mouse ventricles and that NCS-1 co-immunoprecipitates with Kv4.3 from (adult mouse) ventricular extracts. In addition, co-expression studies in HEK-293 cells reveal that NCS-1 increases membrane expression of Kv4 alpha-subunits and functional Kv4-encoded K(+) current densities. Co-expression of NCS-1 also decreases the rate of inactivation of Kv4 alpha-subunit-encoded K(+) currents. In contrast to the pronounced effects of Kv channel interacting proteins on Kv4 channel gating, however, NCS-1 co-expression does not measurably affect the voltage dependence of steady-state inactivation or the rate of recovery from inactivation of Kv4-encoded K(+) currents. Taken together, these results suggest that NCS-1 is an accessory subunit of Kv4-encoded I(to,f) channels that functions to regulate I(to,f) density in the mammalian myocardium.

Heterogeneous expression of voltage-gated potassium channels in the heart: roles in normal excitation and arrhythmias.

In the mammalian myocardium, there are marked regional differences in action potential waveforms and frequency dependences. This heterogeneity impacts the normal dispersion of ventricular repolarization and appears to reflect the differential expression of voltage-gated K+ channels. Multiple types of voltage-gated K+ currents have been distinguished in mammalian ventricles and, in many cases, the K+ (Kv) channel pore-forming (alpha) and accessory (beta) subunits encoding these channels have been identified. In the diseased myocardium, remodeling of voltage-gated K+ currents occurs, influencing propagation and rhythmicity, effects that can lead to increased dispersion of ventricular repolarization and create substrates for reentrant arrhythmias. Targeting the K+ channels that function to maintain the normal dispersion of ventricular repolarization could be effective in treating cardiac arrhythmias.

Role of heteromultimers in the generation of myocardial transient outward K+ currents.

Previous studies have demonstrated a role for Kv4 alpha subunits in the generation of the fast transient outward K+ current, I(to,f), in the mammalian myocardium. The experiments here were undertaken to explore the role of homomeric/heteromeric assembly of Kv4.2 and Kv4.3 and of the Kv channel accessory subunit, KChIP2, in the generation of mouse ventricular I(to,f). Western blots reveal that the expression of Kv4.2 parallels the regional heterogeneity in I(to,f) density, whereas Kv4.3 and KChIP2 are uniformly expressed in adult mouse ventricles. Antisense oligodeoxynucleotides (AsODNs) targeted against Kv4.2 or Kv4.3 selectively attenuate I(to,f) in mouse ventricular cells. Adenoviral-mediated coexpression of Kv4.2 and Kv4.3 in HEK-293 cells and in mouse ventricular myocytes produces transient outward K+ currents with properties distinct from those produced on expression of Kv4.2 or Kv4.3 alone, and the gating properties of the heteromeric Kv4.2/Kv4.3 channels in ventricular cells are more similar to native I(to,f) than are the homomeric Kv4.2 or Kv4.3 channels. Biochemical studies reveal that Kv4.2, Kv4.3, and KChIP2 coimmunoprecipitate from adult mouse ventricles. In addition, most of the Kv4.2 and KChIP2 are associated with Kv4.3 in situ. Taken together, these results demonstrate that functional mouse ventricular I(to,f) channels are heteromeric, comprising Kv4.2/Kv4.3 alpha subunits and KChIP2. The results here also suggest that Kv4.2 is the primary determinant of the regional heterogeneity in I(to,f) expression in adult mouse ventricle.