Effects of angiotensin-converting enzyme inhibitor and angiotensin Ⅱ receptor blocker on one-year outcomes of patients with atrial fibrillation: insights from a multicenter registry study in China

Objective To evaluate the effect of angiotensin-converting enzyme inhibitor(ACEI)/angiotensin Ⅱ receptor blocker(ARB)therapy on the prognosis of patients with atrial fibrillation(AF).Methods A total of 1,991 AF patients from the AF registry were divided into two groups according to whether they were treated with ACEI/ARB at recruitment.Baseline characteristics were carefully collected and analyzed.Logistic regression was utilized to identify the predictors of ACEI/ARB therapy.The primary endpoint was all-cause mortality,while the secondary endpoints included cardiovascular mortality,stroke and major adverse events(MAEs)during the one-year follow-up period.Univariable and multivariable Cox regression were performed to identify the association between ACEI/ARB therapy and the one-year outcomes.Results In total,759 AF patients(38.1%)were treated with ACEI/ARB.Compared with AF patients without ACEI/ARB therapy,patients treated with ACEI/ARB tended to be older and had a higher rate of permanent AF,hypertension,diabetes mellitus,heart failure(HF),left ventricular ejection fraction(LVEF)<40%,coronary artery disease(CAD),prior myocardial infarction(MI),left ventricular hypertrophy,tobacco use and concomitant medications(all P<0.05).Hypertension,HF,LVEF<40%,CAD,prior MI and tobacco use were determined to be predictors of ACEI/ARB treatment.Multivariable analysis showed that ACEI/ARB therapy was associated with a significantly lower risk of one-year all-cause mortality[hazard ratio(HR)(95%CI):0.682(0.527-0.882),P=0.003],cardiovascular mortality[HR(95%CI):0.713(0.514-0.988),P=0.042]and MAEs[HR(95%CI):0.698(0.568-0.859),P=0.001].The association between ACEI/ARB therapy and reduced mortality was consistent in the subgroup analysis.Conclusions In patients with AF,ACEI/ARB was related to significantly reduced one-year all-cause mortality,cardiovascular mortality and MAEs despite the high burden of cardiovascular comorbidities.

Effect of angiotensin Ⅱ type 1 receptor blocker and angiotensin converting enzyme inhibitor on the intraocular growth factors and their receptors in streptozotocin-induced diabetic rats

AIM： To investigate the effect of angiotensin II type 1 receptor blocker （ARB） and angiotensin converting enzyme inhibitor （ACEI） on intraocular growth factors and their receptors in streptozotocin-induced diabetic rats. METHODS： Forty Sprague-Dawley rats were divided into 4 groups： control, diabetes mellitus （DM）, candesartan- treated DM, and enalapril-treated DM （each group, n---10）. After the induction of DM by streptozotocin, candesartan [ARB, 5 mg/（kg · d）] and enalapril [ACEI, 10 mg/（kg · d）] were administered to rats orally for 4Wko Vascular endothelial growth factor （VEGF） and angiotensin II （Ang II） concentrations in the vitreous were measured using enzyme-linked immunosorbent assays, and VEGF receptor 2 and angiotensin II type 1 receptor （ATIR） levels were assessed at week 4 by Western blotting. RESULTS： Vitreous Ang II levels were significantly higher in the DM group and candesartan-treated DM group than in the control （P=0.04 and 0.005, respectively）. Vitreous ATIR increased significantly in DM compared to the other three groups （P〈0.007）. Candesartan-treated DM rats showed higher vitreal ATIR concentration than the enalapril-treated DM group and control （P〈0.001 and P=0.005, respectively）. No difference in vitreous Ang II and ATIR concentration was found between the enalapril- treated DM group and control. VEGF and its receptor were below the minimum detection limit in all 4 groups. CONCLUSION： Increased Ang II and ATIR in the hyperglycemic state indicate activated the intraocular renin-angiotensin system, which is inhibited more effectively by systemic ACEI than systemic ARB.

Peroxisome proliferator-activated receptors for hypertension

Peroxisome proliferator-activated receptors(PPARs) are ligand-activated transcription factors belonging to the nuclear receptor superfamily, which is composed of four members encoded by distinct genes(α, β, γ, and δ). The genes undergo transactivation or transrepression under specific mechanisms that lead to the induction or repression of target gene expression. As is the case with other nuclear receptors, all four PPAR isoforms contain five or six structural regions in four functional domains; namely, A/B, C, D, and E/F. PPARs have many functions, particularly functions involving control of vascular tone, inflammation, and energy homeostasis, and are, therefore, important targets for hypertension, obesity, obesity-induced inflammation, and metabolic syndrome in general. Hence, PPARs also represent drug targets, and PPARα and PPARγ agonists are used clinically in the treatment of dyslipidemia and type 2 diabetes mellitus, respectively. Because of their pleiotropic effects, they have been identified as active in a number of diseases and are targets for the development of a broad range of therapies for a variety of diseases. It is likely that the range of PPARγ agonist therapeutic actions will result in novel approaches to lifestyle and other diseases. The combination of PPARs with reagents or with other cardiovascular drugs, such as diuretics and angiotensin Ⅱ receptor blockers, should be studied.This article provides a review of PPAR isoform characteristics, a discussion of progress in our understanding of the biological actions of PPARs, and a summary of PPAR agonist development for patient management. We also include a summary of the experimental and clinical evidence obtained from animal studies and clinical trials conducted to evaluate the usefulness and effectiveness of PPAR agonists in the treatment of lifestyle-related diseases.

Effects of angiotensin converting enzyme inhibitor,angio-tensin II type I receptor blocker and their combination on postinfarcted ventricular remodeling in rats

Background Transforming growth factor （TGF） β1-Smads signal plays an important role in cardiac remodeling following myocardial infarction （MI）. In addition, both angiotensin converting enzyme inhibitor （ACEI） and angiotensin Ⅱ type Ⅰ receptor blocker （ARB） can effectively prevent left ventricular remodeling. The current study focused on whether the combination of ACEI and ARB is more beneficial for preventing ventricular remodeling and whether Smad proteins mediate this beneficial effect. Methods MI was induced by ligating the left anterior descending coronary artery in rats. Twenty-four hours after ligation, the survived rats were randomly divided into five groups and treated for 8 weeks： placebo group, ACEI group （benazepril 10 mg · kg^-1· d^-1）, ARB group （irbesartan 50mg · kg^-1· d^-1）, ACEI＋ARB group （benazepril 10 mg · kg^-1· d^-1＋irbesartan 50 mg · kg^-1· d^-1） and control group （sham-operated rats）. After 8 weeks, we examined the following indexes： the ratio of ventricular weight to body weight （VW/BW）, left ventricular end diastolic dimension （LVDd）, ejection fraction （EF）, fractional shortening （FS）, ratio of E-wave to A-wave velocity, collagen of noninfarcted zone, the mRNA expression of TGFβ1, Smad 2, and Smad 3 by RT-PCR in noninfarcted zone, the protein expression of Smad 2 and Smad 3 in noninfarcted zone by Western blot. Results VW/BW significantly increased in the placebo groups compared with that in the control group （P〈0.01）. This increase was limited in ACEI, ARB, and combined groups （P〈0.01 compared with placebo group）. There was no significant difference among the three actively treated groups. Collagen was increased in placebo group （5.68±0.5）% compared with that in control group （P〈0.01）. ACEI, ARB and combined treatment attenuated this increase of collagen [（4.3 ± 0.5）%, （3.5 ± 0.5）%, （3.2± 0.4）%] in comparison with that in placebo group （P〈0.01 respectively）. Combined treatment showed more significant effect on collagen deposition. EF and FS significantly decreased, LVDd and E/A significantly increased in placebo group compared with that in control group （P〈0.01 respectively）. ACEI, ARB and combined treatment ameliorated these indexes （P〈0.01 compared with placebo group）. The mRNA expression of TGFβ1, Smad 2, and Smad 3 （0.700±0.045, 0.959±0.037 and 0.850±0.051） increased in placebo group compared with that in control group （P〈0.01）. ACEI, ARB and combined treatment normalized the increase （P〈0.01）. Furthermore, ARB and combined treatment proved to be more effective in decreasing TGF β1 and Smad mRNA expression than ACEI treatment （P〈0.01）. The expression of Smad 2 and Smad 3 protein increased in placebo group compared with that in control group （P〈0.01）. ACEI, ARB and combined treatment normalized the increase （P〈0.01）. Furthermore, ARB and combined treatment proved to be more effective than ACEI alone （P〈0.01）.Conclusions TGFβ1-Smads signal activation is correlated With ventricular remodeling following MI. ACEI and ARB treatment prevents ventricular remodeling by inhibiting expression of Smad 2 and Smad 3. ARB and combined treatment are more effective than ACEI alone.

Effect of angiotensin II type I receptor blocker losartan on bone deterioration in orchiectomized male hypertensive and normotensive rats

Background Epidemiological study showed that the use of angiotensin-converting enzyme inhibitors was associated with higher bone mineral density （BMD） in older people, especially male subjects, which suggested that angiotensin II may have a detrimental effect on bone. Therefore, blocking its effect may have a beneficial effect on bone health. Methods Six-month-old male spontaneously hypertensive rats （SHR） and normotensive Wistar Kyoto rats （WKY） were used. Animals of each model were randomly assigned to the following four groups： Group 1, SHAM operated＋vehicle; Group 2, orchidectomy （ORX）＋vehicle; Group 3, ORX＋low-dose Iosartan （10 mg.kgl.dl）; and Group 4, ORX＋high-dose Iosartan （25 mg-kg-l.d-1）. Blood pressure was recorded weekly. SHAM and ORX operations were performed, followed by daily Iosartan and vehicle treatment from day 4 after operation for 16 weeks. Serum and 24-hour urine samples were collected for measurement of bone turnover markers before euthanasia and then the left femur was collected for measurements of BMD and microarchitecture before mechanical test. Results Urine deoxypyridinoline/urine creatinine （DPD/Cr） ratio was significantly higher in SHR than in WKY. BMD and microarchitecture parameters also showed bone deterioration in SHR. After ORX, serum osteocalcin concentration decreased and urine DPD/Cr ratio increased significantly accompanied by a significant decrease in cortical and trabecular BMD and cortical bone thickness in both WKY and SHR. High-dose Iosartan significantly increased DPD in urine in both SHR and WKY. Apart from marginal favorable changes in bone architecture in WKY treated with high-dose Iosartan, Iosartan did not show significant effect on BMD, bone area, bone microarchitecture, and mechanical properties in both SHR and WKY. Conclusion Angiotensin II type I receptor blocker Iosartan was not able to demonstrate significant effect on ORX-induced bone deterioration in both hypertensive and normotensive rats.