Current and future therapeutic approaches to hyperlipidemia

A Comparative Study on Clinical Evaluation of the Hypolipidemic Effects of Allium sativum, Trigonella foenum-graecum, Commiphora mukul, Picrorhiza kurroa, and Piper nigrum: A Pilot Study

Background

Cardiovascular disease is a leading cause of morbidity and mortality. Therefore, it is essential to prevent cardiovascular diseases by correcting modifiable risk factors such as lowering lipid levels, lowering blood pressure, improving eating habits, giving up smoking, etc. The present study assessed the efficacy of herbal preparation containing Allium sativum (A. sativum), Commiphora mukul (C. mukul), and Trigonella foenum-graecum (T. foenum-graecum) in patients with hyperlipidemia.

Methodology

Patients were given extracts of A. sativum 350 mg, T. foenum-graecum 350 mg, C. mukul 200 mg, Picrorhiza kurroa (P. kurroa) 200 mg, and Piper nigrum (P. nigrum) 5 mg. Unichem Laboratories, Mumbai, provided placebo tablets similar in shape and size to herbal tablets. Patients were assessed for compliance, and a complete lipid profile was done at DO, D15, D46, D76, and D106. In addition, total cholesterol and high-density lipoprotein-cholesterol (HDL-C) serum triglyceride were estimated by the respective methods throughout the study.

Results

The weight of the patients remained stable, the mean weight before being 65.42 ± 8.35 kg and after completion of the study being 65.42 ± 8.35 kg. There were no changes in the ECG during or after the drug therapy in any of the patients. Group A comprised nine patients, and group B had ten patients. Serum creatinine (mg %) was 0.94 and 0.95, fasting blood sugar mg (%) was 111.05 and 99.63, and postprandial blood sugar (mg %) was 150.89 and 147.94 on pre-treatment and post-treatment, respectively. The mean serum triglyceride levels in group A were 271.11, 261.11, 293.89, 167.22, and 128.89, and serum HDL- C levels were 46.11, 46.11, 54.44, 52.22, and 54.44. Serum triglyceride levels in group B were 268, 268.5, 202, 171, and 116, and serum HDL- C levels were 48.5, 48, 50, 50, and 53.5 on day 0, 15, 46, 76, and 106, respectively. A significant reduction in total cholesterol levels was observed on D46, D76, and D106, with a maximum reduction on D76 (25.36%). Similarly, a reduction in serum triglyceride was also observed on D46, D76, and D106, with a maximum reduction on D106 (52.02%). A significant difference was observed (P <0.05). There was also a significant reduction of low-density lipoprotein cholesterol (LDL-C) on D46, D76, and D106, with the maximum reduction on D76 (28.79%). There was a significant rise of HDL-C on D46 and D106, with a maximum rise on D106 (15.41%). A significant difference was observed (P <0.05).

Conclusion

The study drugs are safe and efficacious in reducing the total cholesterol, serum triglycerides, LDL-C levels, and increasing HDL-C levels.

The effect of apple cider vinegar on lipid profiles and glycemic parameters: a systematic review and meta-analysis of randomized clinical trials

Background

Elevated lipid profiles and impaired glucose homeostasis are risk factors for several cardiovascular diseases (CVDs), which, subsequently, represent a leading cause of early mortality, worldwide. The aim of the current study was to conduct a systematic review and meta-analysis of the effect of apple cider vinegar (ACV) on lipid profiles and glycemic parameters in adults.

Methods

A systematic search was conducted in electronic databases, including Medline, Scopus, Cochrane Library, and Web of Knowledge, from database inception to January 2020. All clinical trials which investigated the effect of ACV on lipid profiles and glycemic indicators were included. Studies were excluded if ACV was used in combination with other interventions or when the duration of intervention was < 2 weeks. To account for between-study heterogeneity, we performed meta-analysis using a random-effects model.

Results

Overall, nine studies, including 10 study arms, were included in this meta-analysis. We found that ACV consumption significantly decreased serum total cholesterol (− 6.06 mg/dL; 95% CI: − 10.95, − 1.17; I²: 39%), fasting plasma glucose (− 7.97 mg/dL; 95% CI: − 13.74, − 2.21; I²: 75%), and HbA1C concentrations (− 0.50; 95% CI: − 0.90, − 0.09; I²: 91%). No significant effect of ACV consumption was found on serum LDL-C, HDL-C, fasting insulin concentrations, or HOMA-IR. The stratified analysis revealed a significant reduction of serum TC and TG in a subgroup of patients with type 2 diabetes, those who took ≤15 mL/day of ACV, and those who consumed ACV for > 8-weeks, respectively. Furthermore, ACV consumption significantly decreased FPG levels in a subgroup of studies that administered ACV for > 8-weeks. Further, ACV intake appeared to elicit an increase in FPG and HDL-C concentrations in apparently healthy participants.

Conclusion

We found a significant favorable effect of ACV consumption on FPG and blood lipid levels.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03351-w.

Statin Withdrawal: Clinical Implications and Molecular Mechanisms

Retrospective analyses of data from the Platelet Receptor Inhibition in Ischemic Syndrome Management (PRISM), the National Registry of Myocardial Infarction 4, and the Global Registry of Acute Coronary Events (GRACE) trials revealed that the benefits of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) on acute coronary outcomes are rapidly lost and outcomes worsened if statins are discontinued during a patient's hospitalization for an acute coronary syndrome. Withdrawal of statin therapy in the first 24 hours of hospitalization for non-ST-elevation myocardial infarction increased the hospital morbidity and mortality rate versus continued therapy (11.9% vs 5.7%, p<0.01). Data from the Treating New Targets (TNT) study, however, suggested that short-term discontinuation of statin therapy in patients with stable cardiac conditions may not substantially increase the risk of acute coronary syndromes. In patients with acute coronary syndromes who discontinue statins, the rapid increase in risk of an event may result not only from the lost benefits from the therapy, but also from rebound inhibition of vascular protective substances and activation of vascular deleterious substances. Statins inhibit cholesterol synthesis in vascular cells. By reducing levels of isoprenoid intermediates, statins increase the production of nitric oxide and downregulate angiotensin II AT(1) receptors, endothelin-1, vascular inflammatory adhesion molecules, and inflammatory cytokines. These benefits are rapidly lost and often transiently reversed when statins are acutely discontinued. Acute removal of pleiotropic effects and rebound vascular dysfunction may be more important in an acute coronary event, where inflammation promotes rupture of atherosclerotic plaques and inflammatory and prothrombosis markers are present in high concentration, than in stable chronic vascular disease. In the absence of data from randomized controlled trials, current information suggests that statin therapy should be continued, and possibly boosted, during hospitalization for an acute coronary syndrome. Because statins are discontinued during the early hospitalization of many patients, practitioners must ensure that statins are not omitted, unless contraindicated, from the treatment of patients with acute coronary syndromes.

3D QSAR study of hypolipidemic asarones by comparative molecular surface analysis

Three-dimensional quantitative structure-activity relationship (3D QSAR) modeled for alpha-asarone derivatives using the comparative molecular surface analysis (CoMSA) allowed us to reveal a correlation between the activity of these compounds and the electrostatic potential at the molecular surface. The grid formalism (s-CoMSA) allowed us to indicate a pharmacophore that is of key importance for compound activity. The CoMSA formalism coupled with the iterative variable elimination method gives a highly predictive model.

Modeling robust QSAR. 1. Coding molecules in 3D-QSAR--from a point to surface sectors and molecular volumes

Shape analysis is a powerful tool in chemistry and drug design. In the current work, we compare the results of CoMFA and Comparative Molecular Surface Analysis (CoMSA), the 3D-QSAR method, for a series of hypolipidemic and antiplatelet asarones and antifungal N-myristoyltransferase inhibitors. In this publication we show that a sector CoMSA formalism enables an analysis of the biological activity that is more directly related to the molecular shape and individual molecular functionalities than the traditional uniform and directionless CoMFA field. Iterative Variable Elimination allowed us to identify the potential pharmacophoric sites. We modeled QSARs for both series and demonstrate that sector-based molecular descriptors give very predictive models and allow one to generate a spatial interpretation of the QSAR models. In particular, we identified the central aromatic ring and carbonyl functions as the moieties determining the activity of the asarones series, while the pattern of substitution of the aromatic ring determines the activity of N-myristoyltransferase inhibitors.

Syntheses and biological evaluation of 3-substituted amino-1-aryl-6-hydroxy-hex-2-ene-1-ones as antioxidant and hypolipidemic agents

A new series of compounds belonging to 3-substituted amino-1-aryl-6-hydroxy-hex-2-ene-1-ones (4-12a-e) have been synthesized and evaluated for antioxidant and hypolipidemic activities. Amongst all the synthesized compounds, seven compounds, namely 5b, 5d, 6e, 8a, 8b, 10b and 11a, exhibit better antioxidant activity than probucol. Two compounds, 5d and 10b, have been evaluated in detail for antioxidant and hypolipidemic activities and show comparable activity profile to that of probucol and guggulipid. From the present study it may be postulated that the mechanism of action of these compounds could be through activation of lecithin cholesterol acyltransferase (LCAT), liver lipolytic activity, increased faecal bile acid secretion and inhibition of hepatic cholesterol biosynthesis.

Estrogen regulation of angiotensin-converting enzyme mRNA

Estrogen replacement therapy is cardioprotective in postmenopausal women; however, the precise molecular mechanisms for this modulation are not fully elucidated. We previously showed that chronic estrogen replacement therapy reduced angiotensin-converting enzyme (ACE) activity in tissue extracts and serum with an associated reduction in plasma angiotensin II. A reverse transcriptase-polymerase chain reaction assay was developed to determine whether estrogen treatment regulates tissue ACE mRNA concentration. Total RNA was isolated from kidney cortex, kidney medulla, lung, and aorta of ovariectomized Sprague-Dawley rats after 21 days of chronic 17beta-estradiol replacement therapy (5 mg pellet per rat SC) or placebo. A marked decrease in densitometric intensity ratios of amplified ACE cDNA to elongation factor-1alpha control cDNA was observed in all tissues from placebo-treated rats compared with the estradiol-treated rats (renal cortex: 0.29+/-0.04 versus 0.14+/-0.02; renal medulla: 0. 37+/-0.04 versus 0.24+/-0.03; lung: 4.49+/-0.37 versus 2.49+/-0.59; and aorta: 0.41+/-0.04 versus 0.29+/-0.02; all P<0.05). A comparable reduction in ACE activity was detected in tissue extracts from kidney cortex, kidney medulla, and lung of hormone-treated animals. Incubation of purified rat lung ACE with 1 or 10 micromol/L 17beta-estradiol had no effect on enzyme activity. These results suggest that estrogen treatment regulates tissue ACE activity by reducing ACE mRNA concentrations. Thus, the beneficial cardiovascular effects of estrogen may be mediated in part by downregulation of ACE with a consequent reduction in the circulating levels of the vasoconstrictor angiotensin II, a decrease in the metabolism of the vasodilator bradykinin, and an increase in the production of the vasorelaxant angiotensin-(1-7).

Effects of the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, atorvastatin and simvastatin, on the expression of endothelin-1 and endothelial nitric oxide synthase in vascular endothelial cells

Endothelial dysfunction associated with atherosclerosis has been attributed to alterations in the L-arginine-nitric oxide (NO)-cGMP pathway or to an excess of endothelin-1 (ET-1). The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been shown to ameliorate endothelial function. However, the physiological basis of this observation is largely unknown. We investigated the effects of Atorvastatin and Simvastatin on the pre-proET-1 mRNA expression and ET-1 synthesis and on the endothelial NO synthase (eNOS) transcript and protein levels in bovine aortic endothelial cells. These agents inhibited pre-proET-1 mRNA expression in a concentration- and time-dependent fashion (60-70% maximum inhibition) and reduced immunoreactive ET-1 levels (25-50%). This inhibitory effect was maintained in the presence of oxidized LDL (1-50 microg/ml). No significant modification of pre-proET-1 mRNA half-life was observed. In addition, mevalonate, but not cholesterol, reversed the statin-mediated decrease of pre-proET-1 mRNA levels. eNOS mRNA expression was reduced by oxidized LDL in a dose-dependent fashion (up to 57% inhibition), whereas native LDL had no effect. Statins were able to prevent the inhibitory action exerted by oxidized LDL on eNOS mRNA and protein levels. Hence, these drugs might influence vascular tone by modulating the expression of endothelial vasoactive factors.