Regression of left ventricular mass with captopril and metoprolol, and the effects on glucose and lipid metabolism

The relationship between adipose tissue RAAS activity and the risk factors of prediabetes: a systematic review and meta-analysis

METHODS

This systematic review was developed in compliance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-2020) standards. This was accomplished by searching clinical MeSH categories in MEDLINE with full texts, EMBASE, Web of Science, PubMed, Cochrane Library, Academic Search Complete, ICTRP and ClinicalTrial.gov. Reviewers examined all the findings and selected the studies that satisfied the inclusion criteria. The Downs and Black Checklist was used to assess for bias, followed by a Review Manager v5. A Forrest plot was used for the meta-analysis and sensitivity analysis. The protocol for this review was registered with PROSPERO CRD42022320252.

RESULTS

The clinical studies (n = 2) comprised 1065 patients with prediabetes and 1103 normal controls. The RAAS measurements were completed in the adipose tissue. The RAAS components, renin and aldosterone were higher in the prediabetic (PD) compared to the control [mean difference (MD) = 0.16, 95% CI 0.16 (-0.13, 0.45), p = 0.25]. Furthermore, the PD group demonstrated higher triglycerides mean difference [MD = 7.84, 95% CI 7.84 (-9.84, 25.51), p = 0.38] and increased BMI [MD = 0.13, 95% CI 0.13 (-0.74, 0.99), p = 0.77] compared to the control. The overall quality of the studies was fair with a median score and range of 17 (16-18).

CONCLUSION

The current study highlights the relationship between increased BMI, RAAS and insulin resistance which is a predictor of prediabetes. The renin is slightly higher in the prediabetes group without any statistical significance, aldosterone is rather negatively associated with prediabetes which may be attributed to the use of anti-hypertensive treatment.

Comparative efficacy of different types of antihypertensive drugs in reversing left ventricular hypertrophy as determined with echocardiography in hypertensive patients: A network meta-analysis of randomized controlled trials

Reversing left ventricular hypertrophy (LVH) can reduce the incidence of adverse cardiovascular events. However, there is no clear superiority-inferiority differentiation between angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), beta-blockers (BB), calcium channel blockers (CCB), and diuretics in reversing LVH in hypertensive patients. To provide further evidence for choosing the optimal antihypertensive drug for improving LVH, we performed a network meta-analysis of randomized controlled trials (RCTs) based on the Cochrane library database, Embase, and Pubmed, and identified 49 studies involving 5402 patients that were eligible for inclusion. It was found that ARB could improve LVH in hypertensive patients more effectively than CCB (MD -4.07, 95%CI -8.03 to -0.24) and BB (MD -4.57, 95%CI -8.07 to -1.12). Matched comparison of renin-angiotensin system inhibitors (RASi) showed that the effect of ACEI in reducing left ventricular mass index (LVMi) was not effective as that of ARB (MD -3.72, 95%CI -7.52 to -0.11). The surface under the cumulative ranking for each intervention indicated that the use of ARB was more effective among the different types of antihypertensive drugs (97%). This network meta-analysis revealed that the use of ARB in antihypertensive therapy could achieve better efficacy in reversing LVH in hypertensive patients.

Comparison of the Neuroprotective Effects of Aspirin, Atorvastatin, Captopril and Metformin in Diabetes Mellitus

Objective: The aim of this study was to investigate the effect of combined intake of a high dose of aspirin, atorvastatin, captopril and metformin on oxidative stress in the brain cortex and hippocampus of streptozotocin (STZ)-induced diabetic rats. Material and methods: Rats were randomly divided into the following 11 groups: control and diabetic (D), as well as 9 groups that were treated with metformin (M, 300 mg/kg) or aspirin (ASA, 120 mg/kg) alone or in different combinations with captopril (C, 50 mg/kg) and/or atorvastatin (AT, 40 mg/kg) as follows: (D + M), (D + ASA), (D + M + ASA), (D + M + C), (D + M + AT), (D + M + C + ASA), (D + M + C + AT), (D + M + AT + ASA) and (D + M + C + AT + ASA). The rats in treatment groups received drugs by gavage daily for six weeks. Serum lipid profile and levels of oxidative markers in the brain cortex and hippocampus tissues were evaluated. Results: The levels of malondialdehyde in the brain cortex and hippocampus in all the treated groups decreased significantly (p < 0.05). There was a significant increase in the total thiol concentration as well as catalase activity in treated rats in (M + AT), (M + C + ASA), (M + C + AT), (M + AT + ASA) and (M + C + AT + ASA) groups in cortex and hippocampus in comparison with the diabetic rats (p < 0.05). Also, the superoxide dismutase activity in all treated rats with medications was significantly increased compared to the diabetic rats (p < 0.05–0.01). Conclusion: Our findings showed that the combined use of high-dose aspirin, metformin, captopril and atorvastatin potentiated their antioxidant effects on the brain, and hence could potentially improve cognitive function with their neuroprotective effects on hippocampus.

Are there effects of renin-angiotensin system antagonists beyond blood pressure control?

Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are recognized to reduce cardiovascular and renal morbidity and mortality, which is primarily attributed to their antihypertensive effects. Activation of the renin-angiotensin system (RAS) may also play an important role in the pathogenesis of cardiovascular and renal disease through blood pressure-independent mechanisms mediated by angiotensin II. Thus, inhibiting the RAS with either an ARB or an ACE inhibitor may confer additional benefit in people with advanced nephropathy that cannot be explained totally by reductions in blood pressure. Preclinical evidence suggests that blood pressure lowering is not solely responsible for the organ and tissue protective effects of ACE inhibitors or ARBs. Furthermore, clinical studies evaluating effects on end organs and surrogate markers have shown that these agents have blood pressure-independent effects. There is also intriguing evidence that agents in the same class may differ in their effects on renal function despite similar blood pressure control. Support for blood pressure-independent effects comes from outcome studies. Agents evaluated in such studies and that appear to have effects independent of blood pressure lowering include irbesartan, losartan, ramipril, and telmisartan. Taken together, this body of evidence indicates that the clinical benefits of ARBs and ACE inhibitors in patients with advanced nephropathy extend beyond blood pressure reduction. Therefore, although antihypertensive efficacy is of primary importance in choosing a treatment to provide cardiovascular and renal protection, consideration should be given to the effects of an agent that extend beyond blood pressure.

Regression of Left Ventricular Mass by Antihypertensive Treatment

Blood pressure–lowering therapy reduces left ventricular mass, but the question of whether differences exist among drug classes has not been fully resolved. Our aim was to compare the effects of diuretics, β-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers on left ventricular mass regression in patients with hypertension on the basis of prospective, randomized comparative studies. We performed meta-analyses, involving pooled pairwise comparisons of the drug classes and of each class versus other classes statistically combined, and meta-regression analyses to identify the determinants of the regression. The 75 relevant publications involved 84 pairwise comparisons and 6001 patients. Regression of left ventricular mass was significantly less ( P =0.01) with β-blockers (9.8%) than with angiotensin receptor blockers (12.5%), but none of the other analyzable pairwise comparisons between drug classes revealed significant differences ( P >0.10). In addition, β-blockers showed less regression than the other 4 classes statistically combined ( P <0.01), and regression was more pronounced with angiotensin receptor blockers versus the others ( P <0.01). In multivariable meta-regression analysis on all of the treatment arms, β-blocker treatment was a significant and negative predictor of the regression (−3.6%; P <0.01), but this was not the case for the other drug classes, including angiotensin receptor blockers. In conclusion, β-blockers show less regression of left ventricular mass, whereas angiotensin receptor blockers may induce larger regression. The inferiority of β-blockers appears to be more convincing than the superiority of angiotensin receptor blockers.

Relation between myocardial edema and myocardial mass during the acute and convalescent phase of myocarditis--a CMR study

BACKGROUND

Myocardial edema is a substantial feature of the inflammatory response in human myocarditis. The relation between myocardial edema and myocardial mass in the course of healing myocarditis has not been systematically investigated. We hypothesised that the resolution of myocardial edema as visualised by T2-weighted cardiovascular magnetic resonance (CMR) is associated with a decrease of myocardial mass in steady state free precession (SSFP)-cine imaging.

METHODS

21 patients with acute myocarditis underwent CMR shortly after onset of symptoms and 1 year later. For visualization of edema, a T2-weighted breath-hold black-blood triple-inversion fast spin echo technique was applied and the ratio of signal intensity of myocardium/skeletal muscle was assessed. Left ventricular (LV) mass, volumes and function were quantified from biplane cine steady state free precession images. 11 healthy volunteers served as a control group for interstudy reproducibility of LV mass.

RESULTS

In patients with myocarditis, a significant decrease in LV mass was observed during follow-up compared to the acute phase (156.7 +/- 30.6 g vs. 140.3 +/- 28.3 g, p < 0.0001). The reduction of LV mass paralleled the normalization of initially increased myocardial signal intensity on T2-weighted images (2.4 +/- 0.4 vs. 1.68 +/- 0.3, p < 0.0001). In controls, the interstudy difference of LV mass was lower than in patients (5.1 +/- 2.9 g vs. 16.3 +/- 14.2 g, p = 0.02) resulting in a lower coefficient of variability (2.1 vs 8.9%, p = 0.04).

CONCLUSION

Reversible abnormalities in T2-weighted CMR are paralleled by a transient increase in left ventricular mass during the course of myocarditis. Myocardial edema may be a common pathway explaining these findings.

Novel estrogen receptor alpha promoter polymorphism increases ventricular hypertrophic response to hypertension

Given the strong genetic contribution to blood pressure and left ventricular hypertrophy (LVH), and the influence of estrogen on these parameters, we hypothesized that polymorphisms in the estrogen receptor alpha (ERalpha) promoter may influence LVH. Three novel polymorphisms were identified upstream of the ERalpha alternatively spliced exon 1E, within sequence which demonstrated significant promoter activity in vitro. Demonstration of ERalpha E isoform expression in human ventricle by RT-PCR supported a possible functional role for the 1E novel polymorphisms in estrogen signaling in the heart. Indeed, G>A (-721 E) was significantly associated with LVH after controlling for systolic blood pressure and sex in a healthy population (n=74), contributing to 23% of interventricular septum (IVS) width variance (p<0.001) and 9.4% of left ventricular mass index (LVMI) variance (p=0.035). In a separate hypertensive cohort, male carriers of the A allele (n=8) had a 17% increase in IVS (95% CI: 6-28%) and a 19% increase in LVMI (3-34%) compared to GG homozygotes (n=84). We conclude that a novel polymorphism in the promoter of a cardiac mRNA splice isoform of ERalpha is associated with LVH.

Antihypertensive medications and blood sugar: theories and implications

Increased rates of diabetes have been reported with thiazide diuretics and beta-blockers, but not with angiotensin-converting enzyme inhibitors, angiotensin receptor blockers or calcium channel blockers. These observations are important because significant glycemic effects of drugs may be a source of accelerated cardiovascular risk that is not detectable during restricted clinical trial follow-up periods. The extent to which diabetes is affected by these medications remains unclear, as is the precise mechanism by which diabetes is promoted. However, several plausible theories are presented herein. Although drug-induced diabetes has been a concern for several years, not enough information is available to influence prescribing for the majority of patients. The number one priority should be controlling blood pressure in a timely manner.

Long-term exercise training and angiotensin-converting enzyme inhibition differentially enhance myocardial capillarization in the spontaneously hypertensive rat

OBJECTIVES

To investigate whether combined treatment with lisinopril, an angiotensin-converting enzyme (ACE) inhibitor and exercise training would have an additive effect in enhancing the capillary supply of the left ventricular (LV) myocardium in spontaneously hypertensive rats (SHR).

DESIGN

Twelve-week-old male SHR were divided into four groups (10-12 each): sedentary, sedentary treated with lisinopril (15-20 mg/kg per day by gavage), exercise trained, and exercise trained while treated with lisinopril. Exercise training consisted of 1 h a day/5 days a week of running on a treadmill.

METHODS

After 10 weeks of experimental protocols, capillary surface density and length density were sterologically determined in 1 mum thick LV tissue samples from perfuse-fixed hearts.

RESULTS

Lisinopril significantly reduced systolic blood pressure (SBP) and LV mass in the sedentary with lisinopril and exercise trained with lisinopril groups but did not affect the heart rate (HR). Exercise training did not reduce SBP or LV mass, but significantly reduced HR in the exercise trained and exercise trained with lisinopril groups. Lisinopril treatment (sedentary with lisinopril), exercise training (exercise) and their combination (exercise trained with lisinopril) significantly increased myocardial capillary surface area density by 26, 38 and 65% and length density by 38, 48 and 67%, respectively.

CONCLUSION

Lisinopril administration and exercise training independently enhanced myocardial capillarization through a reduction of myocardial mass and stimulation of angiogenesis, respectively. A combination of the two treatments enhanced myocardial capillarization more than either intervention alone. This may aid in the restoration of the normal nutritional status of cardiac myocytes compromised by the hypertrophic state of hypertension.

Prevention of type 2 diabetes mellitus through inhibition of the Renin-Angiotensin system

Type 2 diabetes mellitus is becoming a major health problem associated with excess morbidity and mortality. As the prevalence of type 2 diabetes is rapidly increasing, prevention of the disease should be considered as a key objective in the near future. Besides lifestyle changes, various pharmacological treatments have proven their efficacy in placebo-controlled clinical trials, including antidiabetic drugs such as metformin, acarbose and troglitazone, or antiobesity agents such as orlistat. Arterial hypertension, a clinical entity in which insulin resistance is common, is strongly associated with type 2 diabetes and may precede the disease by several years. While antihypertensive agents such as diuretics or beta-adrenoceptor antagonists may worsen insulin resistance and impair glucose tolerance, newer antihypertensive agents exert neutral or even slightly positive metabolic effects. Numerous clinical trials have investigated the effects of ACE inhibitors or angiotensin II receptor antagonists (ARAs) on insulin sensitivity in hypertensive patients, with or without diabetes, with no consistent results. Almost half of the studies with ACE inhibitors in hypertensive nondiabetic individuals demonstrated a slight but significant increase in insulin sensitivity as assessed by insulin-stimulated glucose disposal during a euglycaemic hyperinsulinaemic clamp, while the other half failed to reveal any significant change. The effects of ARAs on insulin sensitivity are neutral in most studies. Mechanisms of improvement of glucose tolerance and insulin sensitivity through the inhibition of the renin-angiotensin system (RAS) are complex. They may include improvement of blood flow and microcirculation in skeletal muscles and, thereby, enhancement of insulin and glucose delivery to the insulin-sensitive tissues, facilitating insulin signalling at the cellular level and improvement of insulin secretion by the beta cells. Six recent large-scale clinical studies reported a remarkably consistent reduction in the incidence of type 2 diabetes in hypertensive patients treated with either ACE inhibitors or ARAs for 3-6 years, compared with a thiazide diuretic, beta-adrenoceptor antagonist, the calcium channel antagonist amlodipine or even placebo. The relative risk reduction averaged 14% (p = 0.034) in the CAPPP (Captopril Prevention Project) with captopril compared with a thiazide or beta1-adrenoceptor antagonist, 34% (p < 0.001) in the HOPE (Heart Outcomes Prevention Evaluation) study with ramipril compared with placebo, 30% (p < 0.001) in the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) with lisinopril compared with chlortalidone, 25% (p < 0.001) in the LIFE (Losartan Intervention For Endpoint reduction in hypertension study) with losartan compared with atenolol, and 25% (p = 0.09) in the SCOPE (Study on Cognition and Prognosis in the Elderly) with candesartan cilexetil compared with placebo, and 23% (p < 0.0001) in the VALUE (Valsartan Antihypertensive Long-term Use Evaluation) trial with valsartan compared with amlodipine. All these studies considered the development of diabetes as a secondary endpoint, except the HOPE trial where it was a post hoc analysis. These encouraging observations led to the initiation of two large, prospective, placebo-controlled randomised clinical trials whose primary outcome is the prevention of type 2 diabetes: the DREAM (Diabetes REduction Approaches with ramipril and rosiglitazone Medications) trial with the ACE inhibitor ramipril and the NAVIGATOR (Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research) trial with the ARA valsartan. Finally, ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) will also investigate as a secondary endpoint whether it is possible to prevent the development of type 2 diabetes by blocking the RAS with either an ACE inhibitor or an ARA or a combination of both. Thus, the recent consistent observations of a 14-34% reduction of the development of diabetes in hypertensive patients receiving ACE inhibitors or ARAs are exciting. From a theoretical point of view, they emphasise that there are many aspects of the pathogenesis, prevention and treatment of type 2 diabetes that still need to be uncovered. From a practical point of view, they may offer a new strategy to reduce the ongoing epidemic and burden of type 2 diabetes.

Reduction (TELMAR) as assessed by magnetic resonance imaging in patients with mild-to-moderate hypertension--a prospective, randomised, double-blind comparison of telmisartan with metoprolol over a period of six months rationale and study design

The Telmisartan Effectiveness on Left ventricular MAss Reduction (TELMAR) trial will assess the effect of the angiotensin II (Ang II) receptor blocker, telmisartan, on left ventricular hypertrophy (LVH) compared with the b-blocker, metoprolol, at similar antihypertensive doses. The rationale is that antihypertensives reduce LVH, a cardiac adaptation to pressure overload, principally by pressure-related effects. Ang II plays a key role in pressure-independent mechanisms causing LVH, and angiotensin-converting enzyme (ACE) inhibitors induce more pronounced LVH regression than some other antihypertensives. Blocking Ang II Type 1 receptors may be more effective than ACE inhibition in reducing LVH. TELMAR is a prospective, randomised, double-blind, double-dummy, parallel-group trial. A total of 140 patients (age 18 80 years) with uncontrolled essential hypertension (mean daytime systolic blood pressure [SBP] >140 mmHg or diastolic blood pressure [DBP] >90 mmHg and/or night-time SBP >120 mmHg or DBP >70 mmHg, measured by ambulatory blood pressure monitoring [ABPM]) and left ventricular mass index related to height (LVMI) >0.8 g/cm for females, >1.1 g/cm for males (defined by magnetic resonance imaging [MRI]) will be randomised to once-daily telmisartan or metoprolol. The telmisartan dose will be 40 mg for the first two weeks, 80 mg for 5.5 months and 40 mg for the last two weeks. Metoprolol will be given at a dose of 47.5 mg for two weeks, 95 mg for 5.5 months and 47.5 mg for two weeks. Concomitant add-on medication with hydrochlorothiazide and amlodipine will be allowed. The primary endpoint is the percentage change in LVMI at treatment end versus baseline, using MRI. Secondary variables include blood pressure changes and response rates assessed by ABPM and manual cuff sphygmomanometry, and end-systolic wall stress, systolic left ventricular function (LVF) and diastolic LVF determined by MRI. A separate study was performed prior to the main trial to define the normal range of MRI data in an age-matched population.

Long-Term Effects of Irbesartan and Atenolol on the Renin-Angiotensin-Aldosterone System in Human Primary Hypertension

We examined long-term influence of the angiotensin II type 1-receptor blocker irbesartan and the beta1-adrenergic receptor blocker atenolol on some neurohormonal systems implicated in the pathophysiology of cardiac hypertrophy. Thus, 115 hypertensive patients with left ventricular hypertrophy were randomized to receive double-blind irbesartan or atenolol, with additional therapy if needed. Neurohormone measurements and echocardiography were performed at weeks 0, 12, 24, and 48. Left ventricular mass was reduced more by irbesartan than by atenolol (-26 g/m2 versus -14 g/m2, P = 0.024), despite similar reductions in blood pressure. Plasma renin activity and angiotensin II increased (P < 0.001) by irbesartan (0.9 +/- 0.7 to 3.4 +/- 4.2 ng/mL x h, and 3.0 +/- 1.6 to 13.0 +/- 17.7 pmol/L), but decreased (P < 0.01) by atenolol (1.0 +/- 0.6 to 0.7 +/- 0.6 ng/mL x h, and 3.4 +/- 1.6 to 3.2 +/- 2.2 pmol/L). Serum aldosterone decreased (P < 0.05) by both irbesartan (346 +/- 140 to 325 +/- 87 pmol/L) and atenolol (315 +/- 115 to 283 +/- 77 pmol/L). Changes in left ventricular mass by irbesartan related inversely to changes in plasma renin activity, angiotensin II, and aldosterone (all P < 0.05). Plasma levels and 24-hour urinary excretions of catecholamines, plasma leptin, proinsulin, insulin and insulin sensitivity remained largely unchanged in both groups. Thus, the renin-angiotensin aldosterone system appears to be an important non-hemodynamic factor in the regulation of left ventricular mass.

Role of ANG II in coronary capillary angiogenesis at the insulin-resistant stage of a NIDDM rat model

With the use of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of human non-insulin-dependent diabetes mellitus (NIDDM), we assessed whether ANG II is involved in coronary capillary angiogenesis at the insulin-resistant stage of NIDDM (20 wk of age). In OLETF rats, ANG II labeling and angiotensin type 1 (AT(1)) receptor expression in coronary vessels were increased more than in nondiabetic controls. A marked increase in vascular expression of vascular endothelial growth factor (VEGF) at both mRNA and protein levels was found in OLETF rats. The increased expression level of VEGF was associated with accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha) activated by increased advanced glycation end products (AGEs). Morphometric analysis showed a significantly increased total coronary capillary density, which was a result of arterialization of the venular capillary portion in OLETF rats. Treatment of OLETF rats with candesartan, an AT(1) receptor blocker, inhibited vascular expressions of VEGF, HIF-1alpha, and AGEs, and ameliorated the morphometric changes. These results suggest a key role of ANG II in the pathogenesis of the coronary capillary remodeling in this NIDDM model.