Clinical experience in treating hypertension with fixed-dose combination therapy: angiotensin II receptor blocker losartan plus hydrochlorothiazide

Increased Transforming Growth Factor-β Levels Associated With Cardiac Adverse Events in Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a common genetic heart disease characterized by ventricular hypertrophy, myocardial fibrosis, and impaired ventricular relaxation. The exact mechanisms by which fibrosis is caused remain unknown.

HYPOTHESIS

Circulating TGF-β is related to poor prognosis in HCM.

METHODS

We compared TGF-β levels of 49 HCM patients with those of 40 non-HCM patients. We followed the patients with HCM for 18 months and divided them into 2 groups: low TGF-β (≤ 4877 pg/mL) and high TGF-β (> 4877 pg/mL). We compared the 2 groups in terms of brain natriuretic peptide (BNP), echocardiographic parameters, and clinical outcomes including myocardial infarction, arrhythmias, implantable cardioverter-defibrillator implantation, hospitalization, New York Heart Association (NYHA) class, acute heart failure, and mortality.

RESULTS

The HCM patients had higher TGF-β levels than those in the control group (P = 0.005). In the follow-up, those in the high TGF-β group had higher BNP levels, larger left-atrial size, thicker interventricular septum, NYHA class, more hospitalizations, and a greater number of clinical adverse events (P < 0.001, P = 0.01, P < 0.001, P = 0.002, P < 0.001 and P = 0.003, respectively). TGF-β level of > 4877 pg/mL can predict adverse events with a specificity of 75% and a sensitivity of 72% (P = 0.014). In multivariate regression analysis, TGF-β, BNP, and interventricular septum thickness were significantly associated with adverse events (P = 0.028, P = 0.030, and P = 0.034, respectively).

CONCLUSIONS

The TGF-β level is higher in HCM patients and associated with a poor prognosis in HCM.

Treatment with aliskiren/amlodipine combination in patients with moderate-to-severe hypertension: a randomised, double-blind, active comparator trial

AIMS

To assess the extent of reduction in blood pressure (BP) of aliskiren/amlodipine combination therapy compared with amlodipine monotherapy in moderate-to-severe hypertensive patients.

METHODS

This was an 8-week multicentre, randomised, double-blind study. After a 1-to 4-week washout period, eligible patients [mean sitting systolic blood pressure (msSBP) ≥ 160 to < 200 mmHg] were randomised to receive a once-daily dose of aliskiren/amlodipine 150/5mg (n = 244) or amlodipine 5 mg (n = 241) for 1 week, followed by up-titration to aliskiren/amlodipine 300/10 mg or amlodipine 10 mg for 7 weeks. Efficacy outcome measures included change from baseline to week 8 endpoint in msSBP (primary endpoint), mean sitting diastolic blood pressure (msDBP), and BP control rate (< 140/90 mmHg). Safety was assessed by monitoring and recording all adverse events (AEs) and laboratory abnormalities.

RESULTS

Patients' demographic characteristics were balanced between the two groups, mean baseline BP being 171.0/94.3 mmHg for aliskiren/amlodipine and 171.8/95.6 mmHg for amlodipine. Of 485 randomised patients, 433 (89.3%) completed the study. At week 8 endpoint, combination therapy resulted in significantly greater msSBP/msDBP reductions and BP control rate, compared with monotherapy (all: p ≤ 0.0001). The overall incidence of AEs was similar between the two groups. The most commonly reported AE was peripheral oedema with the incidence lower for combination therapy (14.4%) than for monotherapy (18.3%).

CONCLUSION

In this population with considerably elevated BP, use of aliskiren/amlodipine combination showed significantly greater BP reductions and allowed more patients to achieve BP control compared with amlodipine monotherapy, with no additional safety concerns.

What is a preferred angiotensin II receptor blocker-based combination therapy for blood pressure control in hypertensive patients with diabetic and non-diabetic renal impairment?

Hypertension has a major associated risk for organ damage and mortality, which is further heightened in patients with prior cardiovascular (CV) events, comorbid diabetes mellitus, microalbuminuria and renal impairment. Given that most patients with hypertension require at least two antihypertensives to achieve blood pressure (BP) goals, identifying the most appropriate combination regimen based on individual risk factors and comorbidities is important for risk management. Single-pill combinations (SPCs) containing two or more antihypertensive agents with complementary mechanisms of action offer potential advantages over free-drug combinations, including simplification of treatment regimens, convenience and reduced costs. The improved adherence and convenience resulting from SPC use is recognised in updated hypertension guidelines. Despite a wide choice of SPCs for hypertension treatment, clinical evidence from direct head-to-head comparisons to guide selection for individual patients is lacking. However, in patients with evidence of renal disease or at greater risk of developing renal disease, such as those with diabetes mellitus, microalbuminura and high-normal BP or overt hypertension, guidelines recommend renin-angiotensin system (RAS) blocker-based combination therapy due to superior renoprotective effects compared with other antihypertensive classes. Furthermore, RAS inhibitors attenuate the oedema and renal hyperfiltration associated with calcium channel blocker (CCB) monotherapy, making them a good choice for combination therapy. The occurrence of angiotensin-converting enzyme (ACE) inhibitor-induced cough supports the use of angiotensin II receptor blockers (ARBs) for RAS blockade rather than ACE inhibitors. In this regard, ARB-based SPCs are available in combination with the diuretic, hydrochlorothiazide (HCTZ) or the calcium CCB, amlodipine. Telmisartan, a long-acting ARB with preferential pharmacodynamic profile compared with several other ARBs, and the only ARB with an indication for the prevention of CV disease progression, is available in two SPC formulations, telmisartan/HCTZ and telmisartan/amlodipine. Clinical studies suggest that in CV high-risk patients and those with evidence of renal disease, the use of an ARB/CCB combination may be preferred to ARB/HCTZ combinations due to superior renoprotective and CV benefits and reduced metabolic side effects in patients with concomitant metabolic disorders. However, selection of the most appropriate antihypertensive combination should be dependent on careful review of the individual patient and appropriate consideration of drug pharmacology.

Cardiac fibrosis in mice with hypertrophic cardiomyopathy is mediated by non-myocyte proliferation and requires Tgf-β

Mutations in sarcomere protein genes can cause hypertrophic cardiomyopathy (HCM), a disorder characterized by myocyte enlargement, fibrosis, and impaired ventricular relaxation. Here, we demonstrate that sarcomere protein gene mutations activate proliferative and profibrotic signals in non-myocyte cells to produce pathologic remodeling in HCM. Gene expression analyses of non-myocyte cells isolated from HCM mouse hearts showed increased levels of RNAs encoding cell-cycle proteins, Tgf-β, periostin, and other profibrotic proteins. Markedly increased BrdU labeling, Ki67 antigen expression, and periostin immunohistochemistry in the fibrotic regions of HCM hearts confirmed the transcriptional profiling data. Genetic ablation of periostin in HCM mice reduced but did not extinguish non-myocyte proliferation and fibrosis. In contrast, administration of Tgf-β-neutralizing antibodies abrogated non-myocyte proliferation and fibrosis. Chronic administration of the angiotensin II type 1 receptor antagonist losartan to mutation-positive, hypertrophy-negative (prehypertrophic) mice prevented the emergence of hypertrophy, non-myocyte proliferation, and fibrosis. Losartan treatment did not reverse pathologic remodeling of established HCM but did reduce non-myocyte proliferation. These data define non-myocyte activation of Tgf-β signaling as a pivotal mechanism for increased fibrosis in HCM and a potentially important factor contributing to diastolic dysfunction and heart failure. Preemptive pharmacologic inhibition of Tgf-β signals warrants study in human patients with sarcomere gene mutations.