Investigating the effects of first line and second line antiretroviral drugs on HIV exposed endothelial function - A clinical study, supported by a mechanistic in-vitro approach

Charania, Sana (2017-03)

Thesis (MMed)--Stellenbosch University, 2017

Thesis

ENGLISH ABSTRACT : Background: There is an interaction between HIV, antiretroviral treatment (ART) and endothelial dysfunction; furthermore, HIV-infected individuals (± ART) show an increased incidence of cardiovascular risk factors. However, the evidence stems mainly from studies in developed countries with a paucity of data on these interactions in the South African context. Aims: To investigate the effects of first line and second line ART on HIV exposed vascular endothelial function, in a clinical and in vitro setting. Methods: In the clinical study, participants were recruited in Worcester and allocated to one of four study groups: HIV-negative, HIV-positive ART naïve, HIV-positive first line ART and HIV-positive second line ART. Data were collected via health questionnaires, anthropometric assessments, blood pressure measurements, brachial artery flow mediated dilatation (FMD) and blood chemistry analyses (C-reactive protein (CRP), fasting glucose, HbA1c, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, as well as CD4 count and viral load in HIV-infected individuals). For the in vitro sub-study, a conditioned growth medium was developed containing HIV-related proteins in which aortic endothelial cells (AECs) were incubated. Additionally, AECs were treated with first and second ART drugs. End-points were nitric oxide (NO) production, cell viability and ROS production measured by flow cytometric analysis. Results: There were no inter-group differences with regard to FMD. The median BMI and waist circumference measurements were lower in the HIV-positive groups versus HIV-negative (p < 0.05). Median total cholesterol levels were lower (p < 0.05) in the HIV-positive ART groups versus HIV-negative, and higher in the HIV-positive first line ART group versus the ART naïve group (p< 0.05). Furthermore, mean LDL-cholesterol levels were lower in all HIV-positive groups versus HIV-negative (p< 0.05). Median HBA1C% values were lower in the HIV-positive second line ART versus ART-naïve group (p < 0.05). Regression analyses showed that smoking in first line ART, and CRP and CD4 levels in second line ART were negatively associated with FMD%. In the in vitro sub-study, the HIV-1 gp160 protein was identified in the HIV-conditioned medium. No effects were observed in HIV-conditioned medium treated AECs. In the first and second line ART dose-response investigations, it was found that double first line drug concentration and normal second line drug concentration exerted no harmful effects on AECs. Discussion and Conclusion: Clinical data suggested that the cardiovascular risk profile appeared to be more favourable in HIV-positive groups versus HIV-negative. There were no inter-group differences in terms of endothelial function (FMD). CD4 and CRP, as well as female gender were independent predictors of vascular endothelial function in the HIV-positive second line ART group. Furthermore, smoking was found to be a negative independent predictor of endothelial function in the HIV-positive first line ART group. The in vitro findings showed that the HIV-conditioned medium protocol successfully resulted in the expression of the HIV-1 gp160 protein; however, the conditioned medium failed to induce injury. In the ART dose-response investigations, the double drug concentration for first line ART and normal drug concentration for second line ART, could be considered a safe concentration to use in future investigations.

AFRIKAANSE OPSOMMING : Agtergrond: Daar bestaan ‘n interaksie tussen MIV, antiretrovirale terapie (ART) en endoteeldisfunksie; verder toon MIV-geïnfekteerde persone (±ART) ‘n hoër insidensie van kardiovaskulêre risikofaktore. Hierdie verwantskappe is hoofsaaklik bepaal in populasies van ontwikkelde lande en daar is ‘n tekort aan data in die Suid-Afrikaanse konteks. Doelwitte: Om die effekte van eerste en tweede linie ART op MIV-blootgestelde vaskulêre endoteelfunksie in ‘n kliniese en in vitro omgewing te ondersoek. Metodes: In die kliniese studie was deelnemers in Worcester gewerf en in een van vier studiegroepe ingedeel: MIV-negatief, MIV-positief sonder ART, MIV-positief eerste linie ART en MIV-positief tweede linie ART. Data is ingesamel via vraelyste, antropometriese metings, bloeddruk bepalings, bragiale arterie vloei-gemedieerde dilatasie (FMD) en bloed biochemiese analises (C-reaktiewe proteïen (CRP), vastende glukose, HbA1C, totale cholesterol, LDL-cholesterol, HDL-cholesterol, trigliseriede, asook CD4 telling en virale lading in MIV-geïnfekteerde individue). Vir die in vitro sub-studie was ‘n gekondisioneerde groeimedium ontwikkel wat MIV-verwante proteïene bevat waarin aorta endoteelselle (AECs) geïnkubeer was. Verder was AECs met eerste en tweede linie ART middels behandel. Eindpunte was stikstofoksied (NO) produksie, sellewensvatbaarheid en ROS produksie soos gemeet met vloeisitometriese analise. Resultate: Daar was geen inter-groep verskille t.o.v. FMD nie. Die mediaan BMI en middellyf omtrek metings was laer in die MIV-positiewe groepe versus MIV-negatief (p<0.05). Mediaan totale cholesterol vlakke was laer (p<0.05) in die MIV-positiewe ART groepe versus MIV-negatief, en hoër in die MIV-positief eerste linie ART groep versus geen ART (p<0.05). Verder was die gemiddelde LDL-cholesterol vlakke laer in alle MIV-positiewe groepe versus die MIV-negatiewe groep (p<0.05). Mediaan HbA1c% waardes was laer in die MIV-positiewe tweede linie ART groep versus MIV-positief sonder ART (p<0.05). Regressie analises het getoon dat rook in eerste linie ART, en CRP en CD4 vlakke in tweede linie ART negatief met FMD% geassosieer het. In die in vitro sub-studie was die MIV-1 gp160 proteïen geïdentifiseer in die MIV-gekondisioneerde medium. Geen effekte was in AECs wat aan MIV-gekondisioneerde medium blootgestel was, waargeneem nie. In die eerste en tweede linie ART dosis-respons eksperimente, het die dubbel dosis eerste linie ART en normale dosis tweede linie ART geen nadelige effekte op die AECs uitgeoefen nie. Bespreking en Slotsom: Die kliniese data toon ‘n meer gunstige kardiovaskulêre risiko profiel in die MIV-positiewe groepe versus MIV-negatiewe groep. Daar was geen inter-groep verskille t.o.v. endoteelfunksie (FMD) nie. CD4 en CRP, sowel as vroulike geslag was onafhanklike voorspellers van vaskulêre endoteelfunksie in die MIV-positiewe tweede linie ART groep. Verder was rook ‘n negatiewe onafhanklike voorspeller van endoteelfunksie in die MIV-positiewe eerste linie ART groep. Die in vitro data het getoon dat die MIV-gekondisioneerde protokol op suksesvolle wyse tot die uitdrukking van die MIV-1 gp160 proteïen gelei het, hoewel die gekondisioneerde medium nie daarin kon slaag om skade te veroorsaak nie. In die ART dosis-respons eksperimente is aangetoon dat die dubbel dosis eerste linie ART en normale dosis tweede linie ART ‘n veilige konsentrasie is wat in toekomstige studies gebruik kan word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100961
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