Role of Angiotensin-Converting Enzyme Inhibitors in Vascular Modulation: Beyond the Hypertensive Effects

Angiotensin-Converting Enzyme Inhibitors/Angiotensin Receptor Blockers: Anti-arrhythmic Drug for Arrhythmogenic Right Ventricular Cardiomyopathy

Background: Current treatment guidelines for arrhythmogenic right ventricular cardiomyopathy (ARVC) mainly emphasize on prevention of ventricular arrhythmic events. Despite the progressive nature of ARVC, therapeutic options focusing on decelerating disease progression are scarce.

Methods and Results: This retrospective observational cohort study included 311 patients [age, 39.1 ± 14.4 years; male, 233 (74.9%)] with a definite diagnosis of ARVC as determined by the 2010 Task Force Diagnostic Criteria. Among them, 113 patients (36.3%) received ACEI/ARB treatment. Disease progression was evaluated according to repeat transthoracic echocardiograms with a linear mixed model. Patients receiving ACEI/ARB treatment were associated with slower disease progression reflected by a gradual decrease in tricuspid annular plane systolic excursion than those not receiving ACEI/ARB treatment (0.37 vs. 0.61 mm per year decrease, P < 0.001) and slower dilation of right ventricular outflow tract (0.57 vs. 1.06 mm per year increased, P = 0.003). Cox proportional hazard regression models were used to evaluate the association between life-threatening ventricular tachycardia events and ACEI/ARB treatment. A reduced risk of life-threatening ventricular arrhythmia was associated with ACEI/ARB treatment compared to that without ACEI/ARB treatment (adjusted HR: 0.71, 95% CI: 0.52–0.96, P = 0.031).

Conclusions: ACEI/ARB treatment is associated with slower disease progression and lower risk of life-threatening ventricular arrhythmia in patients with ARVC. Delaying disease progression may pave way for reducing life-threatening ventricular arrhythmia risk.

Association Between the Angiotensin-Converting Enzyme Gene Insertion/Deletion Polymorphism and Avascular Necrosis of the Femoral Head

Objective: This study investigated the association between the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and avascular necrosis of the femoral head (ANFH). Materials and Methods: The ACE gene I/D polymorphism was determined in 279 nontraumatic, ANFH Han Chinese patients (divided into idiopathic and steroid- and alcohol-induced subgroups) and 276 age- and gender-matched healthy controls using the polymerase chain reaction. Results: The frequencies of the ACE DD genotype and D allele were significantly higher among the ANFH patients as a whole and also in the idiopathic and steroid- and alcohol-induced ANFH subgroups compared to healthy controls (p < 0.05 for all). Additionally, the DD genotype, compared with the ID+II, ID, and II genotypes, conferred a higher risk of developing ANFH across all clinical subgroups (p < 0.001, odds ratio [OR] = 2.508; p < 0.001, OR = 2.072; p < 0.001, OR = 3.684, respectively) as well in each of the subgroups examined individually, including the idiopathic subgroup (p < 0.001, OR = 2.579; p < 0.001, OR = 2.091; p < 0.001, OR = 3.994, respectively), the steroid-induced subgroup (p = 0.005, OR = 2.345; p = 0.031, OR = 2.050; p = 0.007, OR = 3.000, respectively), and the alcohol-induced subgroup (p < 0.001, OR = 2.488; p = 0.012, OR = 2.050; p = 0.011, OR = 2.659, respectively) of ANFH patients. The ID genotype, compared with the II genotype, conferred a higher risk across all subtypes analyzed together, and in the idiopathic subgroup (p = 0.013, OR = 1.778; p = 0.028, OR = 1.910) analyzed separately. Additionally, the D allele, in comparison with the I allele, conferred a relatively higher risk across all subgroups (p < 0.001, OR = 2.101) as well as in each of the three subgroups examined individually (idiopathic: p < 0.001, OR = 2.178; steroid-induced: p = 0.003, OR = 1.910; and alcohol-induced: p < 0.001, OR = 2.094). Conclusion: The ACE DD and ID genotypes and D allele may be risk factors for susceptibility to ANFH in the Chinese population.

Novel Therapeutic Role for Dipeptidyl Peptidase III in the Treatment of Hypertension

Dipeptidyl peptidase III (DPP III) cleaves dipeptide residues from the N terminus of polypeptides ranging from 3 to 10 amino acids in length and is implicated in pathophysiological processes through the breakdown of certain oligopeptides or their fragments. In this study, we newly identified the biochemical properties of DPP III for angiotensin II (Ang II), which consists of 8 amino acids. DPP III quickly and effectively digested Ang II with Km = 3.7×10(-6) mol/L. In the in vivo experiments, DPP III remarkably reduced blood pressure in Ang II-infused hypertensive mice without alteration of heart rate. DPP III did not affect hemodynamics in noradrenalin-induced hypertensive mice or normotensive mice, suggesting specificity for Ang II. When DPP III was intravenously injected every other day for 4 weeks after Ang II osmotic minipump implantation in mice, Ang II-induced cardiac fibrosis and hypertrophy were significantly attenuated. This DPP III effect was at least similar to that caused by an angiotensin receptor blocker candesartan. Furthermore, administration of DPP III dramatically reduced the increase in urine albumin excretion and kidney injury and inflammation markers caused by Ang II infusion. Both DPP III and candesartan administration showed slight additive inhibition in the albumin excretion. These results reveal a novel potential use of DPP III in the treatment of hypertension and its protective effects on hypertension-sensitive organs, such as the heart and kidneys.

Combination Treatment With Antihypertensive Agents Enhances the Effect of Qiliqiangxin on Chronic Pressure Overload-induced Cardiac Hypertrophy and Remodeling in Male Mice

Supplemental Digital Content is Available in the Text.

We previously showed that Qiliqiangxin (QL) capsules could ameliorate cardiac hypertrophy and remodeling in a mouse model of pressure overload. Here, we compared the effects of QL alone with those of QL combined with the following 3 types of antihypertensive drugs on cardiac remodeling and dysfunction induced by pressure overload for 4 weeks in mice: an angiotensin II type 1 receptor (AT₁-R) blocker (ARB), an angiotensin-converting enzyme inhibitor (ACEI), and a β-adrenergic receptor (β-AR) blocker (BB). Adult male mice (C57B/L6) were subjected to either transverse aortic constriction or sham operation for 4 weeks, and the drugs (or saline) were orally administered through gastric tubes. Cardiac function and remodeling were evaluated through echocardiography, catheterization, histology, and analysis of hypertrophic gene expression. Cardiomyocyte apoptosis and autophagy, AT₁-R and β₁-AR expression, and cell proliferation–related molecules were also examined. Although pressure overload–induced cardiac remodeling and dysfunction, hypertrophic gene reprogramming, AT₁-R and β₁-AR expression, and ERK phosphorylation were significantly attenuated by QL alone, QL + ARB, QL + ACEI, and QL + BB, the attenuation was stronger in the combination treatment groups. Moreover, apoptosis was reduced to a larger extent by each combination treatment than by QL alone, whereas autophagy was more strongly attenuated by either QL + ARB or QL + ACEI. None of the treatments significantly upregulated ErbB2 or ErbB4 phosphorylation, and none significantly downregulated C/EBPβ expression. Therefore, the effects of QL on chronic pressure overload–induced cardiac remodeling may be significantly increased when QL is combined with an ARB, an ACEI, or a BB.

Hypotensive and Angiotensin-Converting Enzyme Inhibitory Activities of Eisenia fetida Extract in Spontaneously Hypertensive Rats

Objectives. This study aimed to investigate the antihypertensive effects of an Eisenia fetida extract (EFE) and its possible mechanisms in spontaneously hypertensive rats (SHR rats). Methods. Sixteen-week-old SHR rats and Wistar-Kyoto rats (WKY rats) were used in this study. Rats were, respectively, given EFE (EFE group), captopril (captopril group), or phosphate-buffered saline (PBS) (normal control group and SHR group) for 4 weeks. ACE inhibitory activity of EFE in vitro was determined. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using a Rat Tail-Cuff Blood Pressure System. Levels of angiotensin II (Ang II), aldosterone (Ald), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1α ) in plasma were determined by radioimmunoassay, and serum nitric oxide (NO) concentration was measured by Griess reagent systems. Results. EFE had marked ACE inhibitory activity in vitro (IC50 = 2.5 mg/mL). After the 4-week drug management, SHR rats in EFE group and in captopril group had lower SBP and DBP, lower levels of Ang II and Ald, and higher levels of 6-keto-PGF1α and NO than the SHR rats in SHR group. Conclusion. These results indicate that EFE has hypotensive effects in SHR rats and its effects might be associated with its ACE inhibitory activity.

Long-term abdominal adiposity activates several parameters of cardiac energy function

Abdominal obesity increases the incidence of cardiac events but reduces mortality when one of these events occurs. The phenomenon called obesity paradox might be related to myocardial energetics. This study was aimed at determining whether long-term abdominal adiposity alters cardiac energy function. Two groups of male Wistar rats were fed a standard or a Western-type (WD) diet for 8 months. The ex vivo coronary reactivity and mechanical function as well as the mitochondrial oxidative phosphorylation (mOxPhos) and hydrogen peroxide release (mH2O2r) were determined. Abdominal adiposity was augmented by the WD. This was also the case for the coronary reactivity to acetylcholine, but the rate pressure product remained roughly stable despite a reduction of the left ventricle-developed pressure partly compensated by a slight increase in heart rate. The prolonged WD administration resulted in an improvement of mOxPhos, but the mH2O2r was exaggerated which was confirmed in the whole cell by a reduced aconitase to fumarase ratio. This did not modify the plasma oxidative stress due to an increased plasma antioxidant status. In conclusion, long-term WD administration improved the cardiac fitness and might predispose the organism to the obesity paradox. Conversely, the increased mitochondrial mH2O2r can precipitate the heart toward cardiomyopathy if the WD is maintained for a longer duration.

Angiotensin II and oxidative stress in the failing heart

SIGNIFICANCE

Despite recent medical advances, cardiovascular disease and heart failure (HF) continue to be major health concerns, and related mortality remains high. As a result, investigation of the mechanisms involved in the development of HF continues to be an active field of study.

RECENT ADVANCES

The renin-angiotensin system (RAS) and its effector molecule, angiotensin (Ang) II, affect cardiac function through both systemic and local actions, and have been shown to play a major role in cardiac remodeling and dysfunction in the failing heart. Many of the downstream effects of AngII signaling are mediated by elevated levels of reactive oxygen species (ROS) and oxidative stress, which have also been implicated in the pathology of HF.

CRITICAL ISSUES

Inhibitors of the RAS have proven beneficial in the treatment of patients at risk for and suffering from HF, but remain only partially effective. ROS can be generated from several different sources, and the oxidative state is normally tightly regulated in the heart. How AngII increases ROS levels and causes dysregulation of the cardiac oxidative state has been the subject of considerable interest in recent years.

FUTURE DIRECTIONS

A better understanding of this process and the mechanisms involved should lead to the development of more effective HF therapies and improved outcomes.

Effects of angiotensin-converting enzyme inhibitory peptide LAP on vascular remodeling

The aim of this article is to study the efficiency of an angiotensin-converting enzyme (ACE)-inhibitory peptide LAP on the blood pressure (BP) and the vascular remodeling in spontaneously hypertensive rats (SHRs). Ten-week-old male SHRs were divided into four groups with 10 animals in each group and treated for 2 months: blank, pseudo-experimental (NS), enalapril (ENA), and LAP. The alterations of BP, plasma angiotensin II (AngII) levels, and morphological changes of left common carotid artery and the third level of superior mesenteric artery were investigated. After 2 weeks of treatment, LAP and ENA significantly decreased BP and the antihypertensive effects lasted till the end of experiment. After 2 months, LAP and ENA also significantly lowered plasma AngII levels. LAP and enalapril significantly lowered vascular medial thickness, media thickness/lumen diameter, medial cross-sectional area, and mean nuclear area of smooth muscle cells in left common carotid artery. When compared to the blank group, LAP and ENA significantly lowered the percentages of collagen fibers in the vascular area of left common carotid artery with 24.84 ± 0.53, 23.36 ± 0.99 versus 31.82 ± 0.57 (blank), respectively, and those of the third level of superior mesenteric artery with 15.82 ± 0.60, 15.15 ± 0.71 versus 23.42 ± 0.72, respectively. LAP had a beneficial effect on BP and vascular remodeling in SHRs. These findings suggest the potential therapeutic value of LAP in the treatment of hypertension.

Angiotensin receptor blockers and tumorigenesis: something to be (or not to be) concerned about?

The possibility of carcinogenic side effects of antihypertensive therapies due to their chronic administration has been raised multiple times in the past. Recently, the issue has again drawn attention, this time in relation to angiotensin receptor blockers (ARBs). This, among others, caused both American and European drug regulation authorities to review the underlying evidence concerning the relationship between this class of medications and potential adverse carcinogenic outcome. A plethora of both basic science and preclinical evidence has been generated, and three meta-analyses and one nationwide cohort have focused on this specific question. The current review aims to summarize the contemporary multidisciplinary evidence on whether ARBs may be associated with an increased risk of tumorigenesis.

Pharmacologic management of myxomatous mitral valve disease in dogs

Myxomatous mitral valve disease (MMVD) causing mitral regurgitation is the most important disease of the heart in small animal cardiovascular medicine. Because MMVD is an example of a chronic disease that progresses from mild to severe over years, treatment strategies change with the stage of the disease. In this review the treatment options are compared and contrasted as they are discussed relative to the recently published ACVIM consensus statement regarding the treatment of MMVD. Results from clinical trials and evidence-based medicine are likely to provide significant improvements in the management of MMVD in the coming decades.

Therapeutic potential of c-Myc inhibition in the treatment of hypertrophic cardiomyopathy

Investigating the pathophysiological importance of the molecular and mechanical development of cardiomyopathy is critical to find new and broader means of protection against this disease that is increasing in prevalence and impact. The current available treatment options for cardiomyopathy mainly focus on treating symptoms and strive to make the patient more comfortable while preventing progression of disease and sudden death. The proto-oncogene c-Myc (Myc) has been shown to be increased in many different types of heart disease, including hypertrophic cardiomyopathy, before any signs of the disease are present. As the mechanisms of action and multiple pathways of dependent actions of Myc are being dissected by many research groups, inhibition of Myc is becoming an attractive paradigm for prevention and treatment of cardiomyopathy and heart failure. Elucidating the role Myc plays in the development, propagation and perpetuation of cardiomyopathy and heart failure will one day translate into potential therapeutics for cardiomyopathy.

Angiotensin II type 1 receptor antagonists in the treatment of hypertension in elderly patients: focus on patient outcomes

Hypertension in the elderly is one of the main risk factors of cardiovascular and cerebrovascular diseases. Knowledge regarding the mechanisms of hypertension and specific considerations in managing hypertensive elderly through pharmacological intervention(s) is fundamental to improving clinical outcomes. Recent clinical studies in the elderly have provided evidence that angiotensin II type 1 (AT(1)) receptor antagonists can improve clinical outcomes to a similar or, in certain populations, an even greater extent than other classical arterial blood pressure-lowering agents. This newer class of antihypertensive agents presents several benefits, including potential for improved adherence, excellent tolerability profile with minimal first-dose hypotension, and a low incidence of adverse effects. Thus, AT(1) receptor antagonists represent an appropriate option for many elderly patients with hypertension, type 2 diabetes, heart failure, and/or left ventricular dysfunction.

Knocking out angiotensin II in the heart

Despite ongoing medical advances, cardiovascular disease continues to be a leading health concern. The renin-angiotensin system (RAS) plays an important role in regulating cardiovascular function, and is, therefore, the subject of extensive study. Several drugs currently used to treat hypertension and heart failure are designed to target angiotensin II synthesis and function, but thus far, none have been able to completely block the effects of RAS signaling. This review discusses current and emerging approaches towards inhibiting cardiac RAS function in order to further improve cardiovascular disease outcomes.

Rosuvastatin restored adrenergic and nitrergic function in mesenteric arteries from obese rats

BACKGROUND AND PURPOSE

We investigated whether high-fat diet (HFD)-induced obesity was associated with changed function of components of the mesenteric innervation (adrenergic, sensory and nitrergic), the mechanisms involved and the possible effects of rosuvastatin on these changes.

EXPERIMENTAL APPROACH

Male Wistar rats were divided into three groups. (i) rats fed a standard diet (control group); (ii) rats fed a HFD (33.5% fat) for 7 weeks; and (iii) rats fed a HFD and treated with rosuvastatin (15 mg·kg(-1) ·day(-1) ) for 7 weeks. Segments of isolated mesenteric arteries were exposed to electric field stimulation (EFS) with or without tetrodotoxin, phentolamine, 7-nitroindazole (7NI) or N(ω) nitro-L-arginine methyl ester (L-NAME). Noradrenaline, ATP and NO release, and nNOS expression were also measured.

KEY RESULTS

EFS induced a greater frequency-dependent contraction in obese than in control rats. In HFD rats, phentolamine reduced contractions elicited by EFS, but noradrenaline release was greater and ATP release decreased. L-NAME and 7NI increased contractions to EFS in segments from control rats, but not in those from HFD rats. NO release and nNOS expression were lower in arterial segments from HFD rats than in control rats. All these changes in HFD rats were reversed by treatment with rosuvastatin.

CONCLUSIONS AND IMPLICATIONS

Neural control of mesenteric vasomotor tone was altered in HFD rats. Enhanced adrenergic and diminished nitrergic components both contributed to increased vasoconstrictor responses to EFS. All these changes were reversed by rosuvastatin, indicating novel mechanisms of statins in neural regulation of vascular tone.

Overcoming challenges in Type 2 diabetes management to improve patient outcomes

As obesity and Type 2 diabetes mellitus reach epidemic proportions worldwide, glycemic control and prevention of complications have become even more critical. We searched studies published between January 2006 and January 2010 to identify and discuss the challenges facing healthcare professionals and patients in reaching glycemic targets. MEDLINE and Derwent Drug File searches were conducted with the following search terms: Type 2 diabetes mellitus, medication adherence, antihyperglycemic agents, glucose control, and clinical inertia. In this article we will outline the commonly used medications and present the advantages and disadvantages of each class of drug. Additionally, we will present the dipeptidyl peptidase-4 inhibitors and their place in the treatment of patients with Type 2 diabetes mellitus.