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.

Imperial, Emiliana Gomes (2017-03)

Thesis (MMed)--Stellenbosch University, 2017

Thesis

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.

AFRIKAANSE OPSOMMING : Inleiding Antiretrovirale middels (ART) het gelei tot hoër lewensverwagtinge in die menslike immuniteitsgebreksvirus (MIV)-populasie, maar ongelukkig ook tot ‘n verhoogde risiko vir kardiovaskulêre siektes (KVS). Alhoewel daar voldoende gepubliseer is oor die anti-oksidant effekte van rooibos op die kardiovaskulêre sisteem, is daar ‘n tekort aan inligting oor die potensiaal van rooibos as aanvulling tydens ART gebruik. Doelwit Om in manlike Wistar rotte die kardiovaskulêre effekte van Aspalathus linearis/rooibos as aanvulling tydens ART te ondersoek. Om verder ook die effekte van rooibostee op die kardiovaskulêre profiel van pasiënte op ART te ondersoek. Metodes Rotte was ewekansig verdeel in groepe wat vir 9 weke met ‘n vaste kombinasie dosis (Efavirenz 600mg, emtricitabine 200mg, tenofovir 300mg) en ‘n 2% (w/v) rooibostee oplossing, alleen of in kombinasie, behandel was. Harte was geperfuseer middle van ‘n geïsoleerde werkhart model, en was blootgestel aan 20 min globale-iskemie of 35 min streeks-iskemie. Funksionele veranderlikes was gemeet en die persentasie herstel asook infarktgrootte bereken. Vaskulêre reaktiwiteit was bepaal deur gebruik te maak van aorta ringe, waar die torakale aorta (met of sonder perivaskulêre vet (PVAT)) aan fenielefrien-geïnduseerde kontraksie en asetielkolien-geïnduseerde verslapping blootgestel was. Rot serum was vir biochemiese analises versamel. Deelnemers van die menslike studie was gewerf, waarna bloedmonsters deur ‘n opgeleide verpleegster geneem is. Bloeddruk en antropometriese metings was bepaal, en bloedmonsters was vir biochemiese analise voorberei. Resultate ART behandeling het tot ‘n vergrote infarkt grootte gelei [Kontrole (% risiko-area): 28.17±5.10, ART: 50.56±4.08). Hierdie resultaat was nie waargeneem in die Rooibos+ART groep nie. Aorta ring eksperimente sonder PVAT het getoon dat ART verslapping verminder het in vergelyking met kontrole diere (p=0.03), terwyl kombinasie behandeling met rooibos hierdie effek opgehef het (p=0.003). Rooibos behandeling het in vergelyking met kontrole (p=0.01), ART (p=0.0457) en die kombinasie (p=0.0468), tot verhoogde kontraksie van aortas gelei. In die teenwoordigheid van PVAT, het al die groepe minder verslap as die Kontrole+PVAT groep; Rooibos+PVAT groep (p<0.0001), ART+PVAT (p<0.01) en Rooibos+ART+PVAT (p<0.01). Area onder die kurwe (AOK): Kontrole+PVAT, 0.00099; Rooibos+PVAT: 0.00079; ART+PVAT, 0.00091; ART+Rooibos+PVAT, 0.00088. Rooibos en ART behandeling het tot verhoogde kontraksie in vergelyking met kontrole diere gelei (p=0.006 en p=0.03 onderskeidelik). AOK: Kontrole+PVAT, 31.45; Rooibos+PVAT: 43.42; ART+PVAT, 36.32; ART+Rooibos+PVAT, 33.34. Die teenwoordigheid van PVAT het oor die algemeen tot ‘n verlaging in kontraksie gelei [Kontrole+PVAT versus Kontrole-PVAT (p<0.0001); Rooibos+PVAT versus RooibosPVAT (p<0.0001); ART+PVAT versus ART-PVAT (p<0.0001); Rooibos+ART+PVAT versus Rooibos+ARTPVAT (p<0.0001)]. In vergelyking met ander groepe, het Rooibos behandeling tot ‘n betekenisvolle verlaging in totale cholesterol gelei (p=0.048). Epidemiologiese data het gewys dat ongeag MIV-status en ART behandeling, het rooibos geen effek op kardiovaskulêre parameters van pasiente nie. Bespreking en gevolgtrekking Die anti-verslappende effekte van ART was nie waargeneem in die teenwoordigheid van rooibos aanvulling nie. ART behandeling het tot vergrote infarkte gelei. Rooibos behandeling het tot ‘n prokontraktiele effek gelei, terwyl PVAT tot ‘n verlaging in kontraksie gelei het. Geen skadelike effekte geassosieer met die huidige ART regime was in die epidemiologiese studie waargeneem nie en verder het rooibos inname geen betekenisvolle effek op kardiovaskulêre parameters van pasiente gehad nie. Verdere navorsing word benodig.

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