Browsing by Author "Imperial, Emiliana Gomes"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Effect of Aspalathus linearis supplementation, during anti-retroviral treatment, on the heart and aortas of male Wistar rats and the effects of drinking rooibos on the cardiovascular profile of patients on ART.
    (Stellenbosch : Stellenbosch University, 2017-03) Imperial, Emiliana Gomes; Webster, Ingrid; Westcott, Corli; Strijdom, Hans; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Medical Physiology
    ENGLISH ABSTRACT : Introduction Improved survival rates in the human immunodeficiency virus (HIV) population, due to the use of antiretroviral therapy (ART), are associated with increased risk for cardiovascular disease (CVD). Although the cardiovascular effects of rooibos as an antioxidant have been well documented its nutraceutical properties have yet to be investigated as a possible supplement in ART. AIM To investigate the cardiovascular effects of Aspalathus linearis/ rooibos infusion supplementation during ART, on male Wistar rats and the effects of rooibos tea consumption on the cardiovascular profiles of patients on ART. Methods Male Wistar rats were randomly divided into groups and treated with a fixed dose combination (Efavirenz 600mg, emtricitabine 200mg, tenofovir 300mg) and a 2% (w/v) rooibos tea solution independently or in combination for 9 weeks. Fluid intake and weights were measured weekly. Hearts were perfused on the isolated working heart rig and subjected to 20min global or 35min regional ischemia. Functional parameters were recorded and percentage recovery and infarct size (IS) calculated. Using the aortic ring protocol for vascular reactivity, thoracic aortas (with and without perivascular adipose tissue (PVAT)) were subjected to phenylephrine-induced contraction as well as acetylcholine-induced relaxation. Rat serum was collected for biochemical analyses. Participants for the human study were recruited and blood samples collected by a phlebotomist. Blood pressure tests were conducted, anthropometric data recorded and samples prepared for biochemical analyses. Results ART increased IS compared to control [Control (% area at risk): 28.17±5.10 , ART: 50.56±4.08] however this was not seen in the Rooibos+ART group. In vascular reactivity experiments, without PVAT, ART significantly diminished relaxation compared to control (p=0.03) whilst this effect was not observed with Rooibos supplementation (p=0.003). Rooibos caused increased contraction compared to control (p=0.01), ART (p=0.0457) and the combination (p=0.0468). In the presence of PVAT all treatment groups relaxed significantly less than controls (p<0.01). Area under the curve (AUC): Control+PVAT, 0.00099; Rooibos+PVAT: 0.00079; ART+PVAT, 0.00091; ART+Rooibos+PVAT, 0.00088. Whilst Rooibos and ART showed significantly higher contraction than the control (p=0.006 and p=0.03 respectively). AUC: Control+PVAT, 31.45; Rooibos+PVAT: 43.42; ART+PVAT, 36.32; ART+Rooibos+PVAT, 33.34. Overall the presence of PVAT caused a significant decrease in contraction compared to the absence thereof; Control+PVAT versus Control -PVAT group (p<0.0001); rooibos +PVAT versus rooibos -PVAT (p<0.0001), ART+PVAT versus ART -PVAT (p<0.0001) and Rooibos+ART +PVAT versus Rooibos+ARTPVAT (p<0.0001). Rooibos caused a significant reduction in total cholesterol (TC) levels (p=0.048) compared to all other groups. Epidemiological data revealed that drinking rooibos had no significant effects on the cardiovascular parameters of patients irrespective of HIV status or ART adherence. Discussion and Conclusion In aortic rings anti-vasodilatory effects of ART were not observed with rooibos supplementation. ART induced significant increase in IS was not observed in the Rooibos + ART treated group. Rooibos exerted pro-contractile effects whilst the presence of PVAT reduced contraction of the aortic rings. Deleterious effects by the current ART regimen were not observed in the epidemiological study and rooibos consumption had no significant effects on the assessed cardiovascular parameters of all patient groups. Further scientific investigation is required.