Effect of Berberine on Cardiovascular Disease Risk Factors: A Mechanistic Randomized Controlled Trial.

Cardiovascular disease (CVD) is a major contributor to the global burden of disease. Berberine, a long-standing, widely used, traditional Chinese medicine, is thought to have beneficial effects on CVD risk factors and in women with polycystic ovary syndrome. The mechanisms and effects, specifically in men, possibly via testosterone, have not been examined previously. To assess the effect of berberine on CVD risk factors and any potential pathway via testosterone in men, we conducted a randomized, double-blind, placebo-controlled, parallel trial in Hong Kong. In total, 84 eligible Chinese men with hyperlipidemia were randomized to berberine (500 mg orally, twice a day) or placebo for 12 weeks. CVD risk factors (lipids, thromboxane A2, blood pressure, body mass index and waist-hip ratio) and testosterone were assessed at baseline, and 8 and 12 weeks after intervention. We compared changes in CVD risk factors and testosterone after 12 weeks of intervention using analysis of variance, and after 8 and 12 weeks using generalized estimating equations (GEE). Of the 84 men randomized, 80 men completed the trial. Men randomized to berberine had larger reductions in total cholesterol (-0.39 mmol/L, 95% confidence interval (CI) -0.70 to -0.08) and high-density lipoprotein cholesterol (-0.07 mmol/L, 95% CI -0.13 to -0.01) after 12 weeks. Considering changes after 8 and 12 weeks together, berberine lowered total cholesterol and possibly low-density lipoprotein-cholesterol (LDL-c), and possibly increased testosterone. Changes in triglycerides, thromboxane A2, blood pressure, body mass index and waist-hip ratio after the intervention did not differ between the berberine and placebo groups. No serious adverse event was reported. Berberine is a promising treatment for lowering cholesterol. Berberine did not lower testosterone but instead may increase testosterone in men, suggesting sex-specific effects of berberine. Exploring other pathways and assessing sex differences would be worthwhile, with relevance to drug repositioning and healthcare.

Randomized controlled trial of vitamin D supplement on endothelial function in patients with type 2 diabetes.

BACKGROUND: Suboptimal vitamin D status is associated with endothelial dysfunction and an increased risk of cardiovascular diseases but it is unclear whether vitamin D supplementation is beneficial. The aim was to investigate the effect of vitamin D supplementation on endothelial function in patients with type 2 diabetes mellitus (DM). METHODS: In a double-blind, placebo-controlled trial, we randomized 100 type 2 DM patients to vitamin D supplement (5000 IU/day, n = 50) or placebo (controls, n = 50) for 12 weeks. Assessment of vascular function with brachial artery flow-mediated dilatation (FMD), circulating levels of endothelial progenitor cells (EPCs) and brachial-ankle pulse wave velocity, and metabolic parameter, high-sensitivity C-reactive protein (hsCRP) and oxidative stress markers were performed before and after the supplementation. RESULTS: After 12 weeks, vitamin D treated patients had significant increases in serum 25-hydroxyvitamin D [25(OH)D] concentration (treatment effect 34.7 ng/mL, 95% CI 26.4-42.9, P < 0.001) and serum ionized calcium (treatment effect 0.037 mmol/L, 95% CI 0.007-0.067, P = 0.018); decreased serum parathyroid hormone concentration (treatment effect -0.55 pmol/L, 95% CI -1.08 to -0.02, P = 0.042) compared to patients who received placebo. Nevertheless, vitamin D supplementation did not improve vascular function as determined by FMD, circulating EPC count or baPWV (all P > 0.05). Furthermore, hsCRP, oxidative stress markers, low- and high-density lipoprotein and glycated hemoglobin were also similar between two groups (all P > 0.05). CONCLUSION: In patients with type 2 DM, 12 weeks oral supplementation of vitamin D did not significantly affect vascular function or serum biomarkers of inflammation and oxidative stress. CLINICAL TRIAL NUMBER: HKCTR-867, www.hkclinicaltrials.com.

Dietary intake of phytoestrogen is associated with increased circulating endothelial progenitor cells in patients with cardiovascular disease.

Endogenous estrogen is known to positively influence the level and functionality of endothelial progenitor cells (EPC). However, the effect of phytoestrogen on EPC is unknown. Isoflavone is a major component of phytoestrogen. This study aims to investigate if the intake of isoflavone has any impact on the circulating level of EPC. We studied 102 consecutive patients (mean age: 66.5 ± 9.5 years, 78% male, all female post-menopausal) with cardiovascular disease (atherothrombotic stroke 62%, coronary artery disease 38%). Circulating levels of CD133(+) EPC were determined by flow cytometry. Non-invasive pulse wave velocity (PWV) was measured. Long-term intake of isoflavone was determined by a validated food frequency questionnaire. Isoflavone intake was positively associated with circulating CD133(+) EPC (r = 0.31, p = 0.001). Patients with circulating CD133(+) EPC <10th percentile had significantly lower isoflavone intake than patients with CD133(+)EPC ≥10th percentile (4.6 ± 3.7 mg/day versus 19.3 ± 30.2 mg/day, p < 0.001). A significant overall linear trend of circulating EPC across increasing tertiles of isoflavone intake was observed (p = 0.004). Adjusted for potential confounders, increased isoflavone intake from the 1st to the 3rd tertile independently predicted increased circulating CD133(+) EPC level by 221 cells/µl (95%CI: 71.4 to 369.8, relative increase 160%, p = 0.004). Gender was not a significant factor (p > 0.05). Furthermore, circulating CD133(+) EPC <10th percentile was independently predictive of increased PWV by 261.7 cm/s (95% CI: 37.1 to 486.2, p = 0.024). The study demonstrated that circulating EPC increased by more than one fold in patients with cardiovascular disease who had higher intake of isoflavone, suggesting that isoflavone may confer vascular protection through enhanced endothelial repair.

Reduction of C-reactive protein with isoflavone supplement reverses endothelial dysfunction in patients with ischaemic stroke.

AIMS: To investigate the effect of oral isoflavone supplement on vascular endothelial function in patients with established cardiovascular disease. METHODS AND RESULTS: A randomized, double-blinded, placebo-controlled trial was performed to determine the effects of isoflavone supplement (80 mg/day, n = 50) vs. placebo (n = 52) for 12 weeks on brachial flow-mediated dilatation (FMD) in patients with prior ischaemic stroke. Compared with controls, FMD at 12 weeks was significantly greater in isoflavone-treated patients [treatment effect 1.0%, 95% confidence interval (95% CI) 0.1-2.0, P = 0.035]. Adjusted for baseline differences in FMD, isoflavone treatment was independently associated with significantly less impairment of FMD at 12 weeks (odds ratio 0.32, 95% CI 0.13-0.80, P = 0.014). The absolute treatment effect of isoflavone on brachial FMD was inversely related to baseline FMD (r = -0.51, P < 0.001), suggesting that vasoprotective effect of isoflavone was more pronounced in patients with more severe endothelial dysfunction. Moreover, isoflavone treatment for 12 weeks resulted in a significant decrease in serum high-sensitivity (hs)-C-reactive protein level (treatment effect -1.7 mg/L, 95% CI -3.3 to -0.1, P = 0.033). Nevertheless, isoflavone did not have any significant treatment effects on nitroglycerin-mediated dilatation, blood pressure, heart rate, serum levels of fasting glucose and insulin, haemoglobin A1c, and oxidative stress as determined by serum superoxide dismutase, 8-isoprostane, and malondialdehyde (all P > 0.05). CONCLUSION: This study demonstrated that 12 week isoflavone treatment reduced serum hs-C-reactive protein and improved brachial FMD in patients with clinically manifest atherosclerosis, thus reversing their endothelial dysfunction status. These findings may have important implication for the use of isoflavone for secondary prevention in patients with cardiovascular disease, on top of conventional interventions.