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.

[摘要] ENGLISH ABSTRACT :IntroductionImproved survival rates in the human immunodeficiency virus (HIV) population, due to the use ofantiretroviral therapy (ART), are associated with increased risk for cardiovascular disease (CVD).Although the cardiovascular effects of rooibos as an antioxidant have been well documented itsnutraceutical properties have yet to be investigated as a possible supplement in ART.AIMTo investigate the cardiovascular effects of Aspalathus linearis/ rooibos infusion supplementationduring ART, on male Wistar rats and the effects of rooibos tea consumption on the cardiovascularprofiles of patients on ART.MethodsMale 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 solutionindependently or in combination for 9 weeks. Fluid intake and weights were measured weekly. Heartswere perfused on the isolated working heart rig and subjected to 20min global or 35min regionalischemia. Functional parameters were recorded and percentage recovery and infarct size (IS)calculated. Using the aortic ring protocol for vascular reactivity, thoracic aortas (with and withoutperivascular adipose tissue (PVAT)) were subjected to phenylephrine-induced contraction as well asacetylcholine-induced relaxation. Rat serum was collected for biochemical analyses. Participants forthe human study were recruited and blood samples collected by a phlebotomist. Blood pressure testswere conducted, anthropometric data recorded and samples prepared for biochemical analyses.ResultsART increased IS compared to control [Control (% area at risk): 28.17±5.10 , ART: 50.56±4.08] howeverthis was not seen in the Rooibos+ART group. In vascular reactivity experiments, without PVAT, ARTsignificantly diminished relaxation compared to control (p=0.03) whilst this effect was not observedwith 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 treatmentgroups 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 Rooibosand 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 absencethereof; 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 significanteffects on the cardiovascular parameters of patients irrespective of HIV status or ART adherence.Discussion and ConclusionIn aortic rings anti-vasodilatory effects of ART were not observed with rooibos supplementation. ARTinduced significant increase in IS was not observed in the Rooibos + ART treated group. Rooibosexerted 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 androoibos consumption had no significant effects on the assessed cardiovascular parameters of allpatient groups. Further scientific investigation is required.

[发布机构] Stellenbosch University