Glucose, blood pressure, and cardiovascular risk

Beneficial effects of carvedilol modulating potassium channels on the control of glucose

The increased prevalence of hypertensive patients with type 2 diabetes mellitus (T2DM) is evident worldwide, leading to a higher risk of cardiovascular disease onset, which is substantially associated with disabilities and mortality in the clinic. In order to achieve the satisfyingly clinical outcomes and prognosis, the comprehensive therapies have been conducted with a beneficial effect on both blood pressure and glucose homeostasis, and clinical trials reveal that some kind of antihypertensive drugs such as angiotensin converting enzyme inhibitors (ACE-I) may, at least in part, meet the dual requirement during the disease management. As a nonselective β-blocker, carvedilol is employed for treating many cardiovascular diseases in clinical practice, including hypertension, angina pectoris and heart failure, and also exhibit the effectiveness for glycemic control and insulin resistance. Apart from alleviating sympathetic nervous system activity, several causes, such as lowering oxygen reactive species, may contribute to the effects of carvedilol on controlling plasma glucose levels, suggesting a feature of this drug having multiple targets. Interestingly, numerous distinct K⁺ channels expressed in pancreatic β-cells and peripheral insulin-sensitive tissues, which play a sentential role in glucose metabolism, are subjected to extensive modulation of carvdilol, establishing a linkage between K⁺ channels and drug's effects on the control of glucose. A variety of evidence shows that the impact of carvedilol on different K⁺ channels, including Kv, K_Ach, K_ATP and K_2 P, can lead to positive influences for glucose homeostasis, contributing to its clinical beneficial effectiveness in treatment of hypertensive patients with T2DM. This review focus on the control of plasma glucose conferred by carvedilol modulation on K⁺ channels, providing the novel mechanistic explanation for drug's actions.

Effects of insulin on cardiovascular events and all-cause mortality in patients with type 2 diabetes: A meta-analysis of randomized controlled trials

AIM

In 2019, the Italian Society of Diabetology and the Italian Association of Clinical Diabetologists nominated an expert panel to develop guidelines for drug treatment of type 2 diabetes. This expert panel, after identifying the effects of glucose-lowering agents on major adverse cardiovascular events (MACEs), all-cause mortality, and hospitalization for heart failure (HHF) as critical outcomes, decided to perform a systematic review and meta-analysis on the effect of insulin with this respect.

DATA SYNTHESIS

A MEDLINE database search was performed to identify all RCTs, up to June 1st, 2021, with duration≥52 weeks, in which insulin was compared with either placebo or active comparators. The principal endpoints were MACE and HHF (restricted for RCT reporting MACEs within their outcomes), all-cause mortality (irrespective of the inclusion of MACEs among the pre-specified outcomes). Mantel-Haenszel odds ratio (MH-OR) with 95% Confidence Interval (95% CI) was calculated for all the endpoints considered. Six RCTs (enrolling 8091 patients and 10,139 in the insulin and control group, respectively) were included in the analysis for MACEs and HF, and 18 in that for all-cause mortality (9760 and 11,694 patients in the insulin and control group, respectively). Treatment with insulin neither significantly increased nor reduced the risk of MACE, all-cause mortality, and HHF in comparison with placebo/active comparators (MH-OR: 1.09, 95% CI 0.97-1.23; 0.99, 95% CI 0.91, 1.08; and 0.90, 95% CI 0.78, 1.04, respectively).

CONCLUSIONS

This meta-analysis showed no significant effects of insulin on incident MACE, all-cause mortality, and HHF.

The glycemic effects of antihypertensive medications

Older antihypertensive medications are believed to be associated with metabolic disturbances, especially raised glucose levels. Owing to this, many physicians shun their use. Newer antihypertensive medications are metabolically neutral or metabolically favorable; therefore, they are looked upon favorably and are chosen as primary medications for the treatment of hypertension. Here we review the literature on the glucose effects of older and newer antihypertensive medications. We also consider what, if any, impact these metabolic effects have on cardiovascular disease outcomes. We show that the diabetogenic effects of thiazide diuretics and beta blockers are small relative to the glucose effects of angiotensin-converting enzyme inhibitors (ACEIs) and calcium channel blockers, and that over time, the glucose differences between older and newer medications diminish. Importantly, we show that the diabetogenic effects of older antihypertensive medications do not translate into increased cardiovascular disease risk.

The effect of carvedilol on blood glucose levels in normal albino rats

BACKGROUND

Carvedilol is a commonly used drug in hypertension, congestive heart failure in diabetics. It has moderate calcium channel blocking property in addition to α1 and non selective β antagonistic activity. Though some studies bring forth the beneficial effects of Carvedilol in cardiovascular comorbidities in diabetes, there is no consensus on its effects on glycaemic levels.

AIMS

To evaluate the effect of oral Carvedilol administration for 5 days on blood glucose levels in normal albino rats through Oral Glucose Tolerance Test.

MATERIAL AND METHODS

Twelve adult albino rats of either sex weighing between 150 - 200 g were selected from central animal facility and randomly divided into 2 groups - Control [Distilled water (1ml/rat orally)] and Test (0.8mg/kg body weight orally) and the respective drugs were administered over 5 days. Following overnight fasting, on the fifth day 1 hour after the last dose of the respective drug, OGTT was performed. The CBG (Capillary Blood Glucose) levels were measured at 0 min, glucose (2g/kg body weight) dissolved in water was administered to all the rats orally. The blood sample from tail vein (obtained by tail snipping) at 60 and 150 minutes were analysed for CBG levels using a standardized glucometer.

STATISTICAL ANALYSIS

Data was presented as Mean ± SEM. One way ANOVA, independent samples t-test, non-parametric tests, percentages and cross tabs were used in the analysis of data within the same group and between different groups when required.

RESULTS

Carvedilol group showed higher CBG levels at all time intervals of OGTT as compared to the Control group i.e., 0, 60 and 150 minutes, the highest being (103.8±5.029 )mg/dl at 60 minutes and was statistically significant. Carvedilol group however showed lesser inter-interval variation compared to the Control group at the same time intervals respectively but was statistically insignificant.

CONCLUSIONS

Carvedilol has hyperglycaemic potential when given orally for 5 days in normal albino rats. Though it may be beneficial in diabetics for various comorbid conditions, the glycaemic control may worsen during its use in subjects with prediabetes, diabetes, high risk diabetes.