Metabolic and vascular effects of silybin in hypertensive patients with high 1-h post-load plasma glucose

Abstract

Hypertensive patients with normal glucose tolerance (NGT) but 1-h post-load plasma glucose ≥ 155 mg/dl (1-h high), during an oral glucose tolerance test (OGTT), show higher insulin resistance and multiple target organ damages. Experimental and clinical studies demonstrate that silybin presents anti-inflammatory and metabolic effects, improving insulin resistance and endothelial dysfunction. This study aims to evaluate the effects of the complex silybin-vitamin E and phospholipids on inflammatory, metabolic and vascular parameters in NGT 1-h high hypertensive patients. This is a pilot, single arm, interventional, longitudinal study enrolling 50 Caucasian NGT 1-h high hypertensive outpatients, 27 men and 23 women, age range 42-60 years (mean + SD = 52 ± 7). After 6 months of silybin intake, there is a significant improvement in metabolic profile. The glucose response during OGTT significantly improves (AUCglucose_0-120 309.6 ± 63.4 at baseline vs 254.6 ± 35.5 at the follow-up, ∆ = - 55, 95% CI from - 67 to - 43, p < 0.0001), so as insulin response (AUCinsulin_0-120 238.2 ± 99.1 vs 159.3 ± 44.9, ∆ = - 78.9, 95% CI from - 100.0 to - 57.8, p < 0.0001), in accordance with the increase of insulin sensitivity index Matsuda. Silybin intake is associated with a significant reduction of both clinical and central systolic blood pressure, with betterment in clinical and central pulse pressure and reduction of arterial stiffness parameters. In conclusion, this study demonstrates that silybin may improve the metabolic aspect and vascular damage in NGT 1-h high hypertensive patients who are at higher metabolic and cardiovascular risk. Thus, in these patients, silybin might strengthen the effect of antihypertensive drugs giving further cardiovascular protection.

Keywords: Essential hypertension; Insulin resistance; Silybin; Vascular damage.