Comparative effectiveness of carvedilol and propranolol on glycemic control and insulin resistance associated with l-thyroxin-induced hyperthyroidism — an experimental study

5-HT2A Receptor and 5-HT Degradation Play a Crucial Role in Atherosclerosis by Modulating Macrophage Foam Cell Formation, Vascular Endothelial Cell Inflammation, and Hepatic Steatosis

Aim: Previously, we found that diabetes-related liver dysfunction is due to activation of the 5-HT _2A receptor (5-HT _2A R) and increased synthesis and degradation of 5-HT. Here, we investigated the role of 5-HT in the development of atherosclerosis.

Methods: The study was conducted using high-fat diet-fed male ApoE ^−/− mice, THP-1 cell-derived macrophages, and HUVECs. Protein expression and biochemical indexes were determined by Western blotting and quantitative analysis kit, respectively. The following staining methods were used: oil red O staining (showing atherosclerotic plaques and intracellular lipid droplets), immunohistochemistry (showing the expression of 5-HT _2A R, 5-HT synthase, and CD68 in the aortic wall), and fluorescent probe staining (showing intracellular ROS).

Results: In addition to improving hepatic steatosis, insulin resistance, and dyslipidemia, co-treatment with a 5-HT synthesis inhibitor and a 5-HT _2A R antagonist significantly suppressed the formation of atherosclerotic plaques and macrophage infiltration in the aorta of ApoE ^−/− mice in a synergistic manner. Macrophages and HUVECs exposed to oxLDL or palmitic acid in vitro showed that activated 5-HT _2A R regulated TG synthesis and oxLDL uptake by activating PKCε, resulting in formation of lipid droplets and even foam cells; ROS production was due to the increase of both intracellular 5-HT synthesis and mitochondrial MAO-A-catalyzed 5-HT degradation, which leads to the activation of NF-κB and the release of the inflammatory cytokines TNF-α and IL-1β from macrophages and HUVECs as well as MCP-1 release from HUVECs.

Conclusion: Similar to hepatic steatosis, the pathogenesis of lipid-induced atherosclerosis is associated with activation of intracellular 5-HT _2A R, 5-HT synthesis, and 5-HT degradation.

Dual targeting of TNF-α and free radical toxic stress as a promising strategy to manage experimental polycystic ovary

CONTEXT

It is now clear that oxidative stress (OS) and chronic low-grade inflammation are two main pathways involved in polycystic ovary syndrome (PCOS) pathogenesis. Therefore, simultaneous targeting of these pathways by means of carvedilol and Semelil (ANGIPARS™), as established medicines with dual anti-cytokine and anti-oxidant potential may be a therapeutic alternative approach to the current treatments.

OBJECTIVE

The objective of this study is to study the protective effects of carvedilol and ANGIPARS™ on inflammatory and oxidative response in hyperandrogenism-induced polycystic ovary (PCO).

MATERIALS AND METHODS

The murine model of PCO was induced by letrozole (1 mg/kg/d; orally) and effective doses of carvedilol (10 mg/kg/d; orally) and ANGIPARS™ (2.1 mg/kg/d; orally) were administrated for 21 d in PCO and non-PCO healthy rats. Ovarian folliculogenesis, sex hormones concentrations, OS, inflammatory, and metabolic biomarkers were assessed in serum and ovaries.

RESULTS

PCO rats exhibited ovarian cystogenesis which was preserved by the application of carvedilol and ANGIPARS™. In comparison with controls, decreased level of the total antioxidant power (TAP) and higher levels of reactive oxygen species (ROS) and lipid peroxidation (LPO) in serum and ovaries (2.41 ± 0.67 versus 0.72 ± 0.11; and 0.17 ± 0.04 versus 0.05 ± 0.01; 5.48 ± 1.30 versus 10.56 ± 0.77; and 7.06 ± 1.94 versus 17.98 ± 0.98; p < 0.05, respectively) were detected in PCO rats. Moreover, the PCO rats exhibited hyperandrogenism due to a 3.7-fold increase in serum testosterone concentration (35.04 ± 3.17 versus 131.09 ± 13.24; p < 0.05) along with a 2.98-fold decrease in serum progesterone (6.19 ± 0.40 versus 18.50 ± 1.03; p < 0.05) and 5.2-fold decrease in serum estradiol (9.30 ± 0.61 versus 48.3 ± 2.10; p < 0.05) when compared with those of the control group. However, similar to the control group, normal levels of OS markers and sex hormones were detected in ANGIPARS™ and carvedilol co-treated PCO rats. Besides, when compared with controls, increased levels of TNF-α (770.75 ± 42.06 versus 477.14 ± 28.77; p < 0.05) and insulin (1.27 ± 0.10 versus 0.36 ± 0.05; p < 0.05) in PCO rats were significantly inhibited by carvedilol and ANGIPARS™ co-treatment.

DISCUSSION AND CONCLUSION

We evidenced the beneficial effects of carvedilol and ANGIPARS™ in PCO, which underpin the new alternative approach in using these kinds of medicines in female reproductive disorders.

The effect of losartan and carvedilol on renal haemodynamics and altered metabolism in fructose-fed Sprague-Dawley rats

The aim of this study is to assess the effects of losartan and carvedilol on metabolic parameters and renal haemodynamic responses to angiotensin II (Ang II) and adrenergic agonists in the model of fructose-fed rat. Thirty-six Sprague-Dawley rats were fed for 8 weeks either 20% fructose solution (F) or tap water (C) ad libitum. F or C group received either losartan or carvedilol (10 mg/kg p.o.) daily for the last 3 weeks of the study (FL and L) and (FCV and CV), respectively, then in acute studies the renal vasoconstrictor actions of Ang II, noradrenaline (NA), phenylephrine (PE) and methoxamine (ME) were determined. Data, mean±SEM were analysed using ANOVA with significance at P <0.05. Losartan and carvedilol decreased the area under the glucose tolerance curve of the fructose-fed group. The responses (%) to NA, PE, ME and Ang II in F were lower (P <0.05) than C (F vs. C, 17±2 vs. 38±3; 24±2 vs. 48±2; 12±2 vs. 34±2; 17±2 vs. 26±2), respectively. L had higher (P <0.05) responses to NA and PE while CV had blunted (P <0.05) responses to NA, PE and Ang II compared to C (L, CV vs. C, 47±3, 9±2 vs. 38±3; 61±3, 29±3 vs. 48±2; 16±3, 4±3 vs. 26±2), respectively. FL but not FCV group had enhanced (P <0.05) responses to NA, PE and ME compared to F (FL vs. F, 33±3 vs. 17±2; 45±3 vs. 24±2; 26±3 vs. 12±2), respectively. Losartan and carvedilol had an important ameliorating effect on fructose-induced insulin resistance. Losartan treatment could be an effective tool to restore normal vascular reactivity in the renal circulation of the fructose-fed rat.

The impact of carvedilol and metoprolol on serum lipid concentrations and symptoms in patients with hyperthyroidism

BACKGROUND

Hyperthyroidism is associated with unpleasant symptoms and hypertension due to increased adrenergic tone. Therefore, beta-blockers are often used in hyperthyroid patients. While some beta-blockers (such as propronolol and metoprolol) may have unwanted effects on lipid profile, carvedilol, a new alpha- and beta-blocker, has been suggested to have some metabolic advantages with respect to lipid profiles in hypertensive patients. However, this has not been shown in hyperthyroid patients.

OBJECTIVE

We aimed to compare the effects of two beta-blockers (metoprolol and carvedilol) on the lipid profiles of hyperthyroid patients with hypertension.

METHODS

Thirty patients with hyperthyroidism and hypertension were randomly assigned to receive either carvedilol (n = 15) or metoprolol (n = 15). Thyroid-stimulating hormone (TSH), free T3, free T4, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride, and total cholesterol levels were measured before and following 3 months of treatment.

RESULTS

Systolic and diastolic blood pressure, heart rate, TSH, and free T4 improved significantly in both treatment groups. There were no statistically significant changes in the lipid parameters in either of the two treatment groups; however, triglyceride levels slightly decreased with carvedilol treatment. There were also no differences between the two groups in terms of the typical symptoms of hyperthyroidism.

CONCLUSION

Carvedilol might be a preferred agent to treat hyperthyroid patients who have hypertension and dyslipidemia. This is likely due to the possible beneficial effect of carvedilol on lipid parameters, especially on triglyceride levels.

Chronic caffeine intake decreases circulating catecholamines and prevents diet-induced insulin resistance and hypertension in rats

We tested the hypothesis that long-term caffeine intake prevents the development of insulin resistance and hypertension in two pathological animal models: the high-fat (HF) and the high-sucrose (HSu) diet rat. We used six groups of animals: control; caffeine-treated (Caff; 1 g/l in drinking water during 15 d); HF; caffeine-treated HF (HFCaff); HSu; caffeine-treated HSu (HSuCaff). Insulin sensitivity was assessed using the insulin tolerance test. Blood pressure, weight gain, visceral fat, hepatic glutathione, plasma caffeine, insulin and NO, and serum NEFA and catecholamines were measured. Caffeine reversed insulin resistance and hypertension induced by both the HF and HSu diets. In the HF-fed animals caffeine treatment restored fasting insulin levels to control values and reversed increased weight gain and visceral fat mass. In the HSu group, caffeine reversed fasting hyperglycaemia and restored NEFA to control values. There were no changes either in plasma NO or in hepatic glutathione levels. In contrast, caffeine totally prevented the increase in serum catecholamines induced by HF and HSu diets. To test the hypothesis that inhibition of the sympathetic nervous system prevents the development of diet-induced insulin resistance we administered carvedilol, an antagonist of β1, β2 and also α1 adrenoceptors, to HF and HSu rats. Carvedilol treatment fully prevented diet-induced insulin resistance and hypertension, mimicking the effect of caffeine. We concluded that long-term caffeine intake prevented the development of insulin resistance and hypertension in HF and HSu models and that this effect was related to a decrease in circulating catecholamines.

Eugenosedin-A prevents hyperglycaemia, hyperlipidaemia and lipid peroxidation in C57BL/6J mice fed a high-fat diet

Objectives

Eugenosedin-A is a serotonin (5-hydroxytryptamine; 5-HT) 5-HT1b/2a and α1/α2/β1-adrenoceptor blocker with anti-oxidative, anti-inflammatory and free-radical scavenging activities. Previous reports demonstrated that 5-HT2a blockers could diminish hyperlipidaemia. This study therefore aimed to investigate the possible uses and mechanisms of eugenosedin-A and other agents in treating hyperlipidaemia.

Methods

C57BL/6J mice were randomly divided into seven groups, fed a regular diet or a high-fat diet alone or supplemented with one of five agents: eugenosedin-A, ketanserin, prazosin, propranolol or atorvastatin (5 mg/kg p.o.) for 8 weeks.

Key findings

Compared with the regular diet, the mice fed the high-fat diet had significantly higher body weight and glucose, insulin and lipid levels. Brain malondialdehyde concentration was increased and liver glutathione peroxidase activity decreased. Addition of eugenosedin-A to the high-fat diet resulted in less weight gain and reduced hyperglycaemia, hyperinsulinaemia and hyperlipidaemia. Lipid and glucose homeostasis were related to decreased hepatic lipogenesis mRNAs and proteins (sterol regulatory element binding protein 1a, fatty acid synthase, sterol-CoA desaturase) and restored adipose peroxisome proliferator-activated receptor γ expression. Eugenosedin-A also enhanced low-density lipoprotein receptor mRNA expression.

Conclusions

Eugenosedin-A may improve plasma lipid metabolism by increasing low-density lipoprotein receptor and peroxisome proliferator-activated receptor γ expression and diminishing sterol regulatory element binding protein 1a, fatty acid synthase and sterol-CoA desaturase. Reduction of plasma glucose and lipid levels may, in turn, reduce insulin concentration, which would explain the marked improvement in obesity-related hyperglycaemia and hyperlipidaemia. Furthermore, eugenosedin-A affected malondialdehyde concentration and glutathione peroxidase activity, suggesting it may have anti-peroxidation effects in mice fed a high-fat diet.