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Hudson P, Woudberg NJ, Kamau F, Strijdom H, Frias MA, Lecour S. HIV-related cardiovascular disease: any role for high-density lipoproteins? Am J Physiol Heart Circ Physiol 2020; 319:H1221-H1226. [PMID: 33006917 DOI: 10.1152/ajpheart.00445.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The introduction of antiretroviral therapy (ART) has improved the life expectancy of patients infected with human immunodeficiency virus (HIV). However, this population is at an increased risk for noncommunicable diseases, including atherosclerotic cardiovascular disease (CVD). Both ART and viral infection may be potential contributors to the pathophysiology of HIV-related CVD. The mechanisms behind this remain unclear, but it is critical to delineate early biomarkers of cardiovascular risk in the HIV population. In this review, we postulate that potential biomarkers could include alterations to high-density lipoprotein (HDL). Indeed, recent data suggest that HIV and ART may induce structural changes of HDL, thus resulting in shifts in HDL subclass distribution and HDL functionality.
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Affiliation(s)
- Peter Hudson
- Department of Medicine, Faculty of Health Sciences, Hatter Institute for Cardiovascular Research in Africa, University of Cape Town, Cape Town, South Africa
| | - Nicholas J Woudberg
- Department of Medicine, Faculty of Health Sciences, Hatter Institute for Cardiovascular Research in Africa, University of Cape Town, Cape Town, South Africa
| | - Festus Kamau
- Faculty of Medicine and Health Sciences, Centre for Cardio-metabolic Research in Africa, Division of Medical Physiology, Stellenbosch University, Stellenbosch, South Africa
| | - Hans Strijdom
- Faculty of Medicine and Health Sciences, Centre for Cardio-metabolic Research in Africa, Division of Medical Physiology, Stellenbosch University, Stellenbosch, South Africa
| | - Miguel A Frias
- Department of Diagnostics, Division of Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Sandrine Lecour
- Department of Medicine, Faculty of Health Sciences, Hatter Institute for Cardiovascular Research in Africa, University of Cape Town, Cape Town, South Africa
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Nogueira Soares R, Machado-Santos AP, Barros-Santos E, Vieira De Oliveira G, Murias JM, Alvares TS. Acute supplementation with beetroot juice improves endothelial function in HIV-infected individuals. Appl Physiol Nutr Metab 2020; 46:213-220. [PMID: 32866396 DOI: 10.1139/apnm-2020-0498] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Human immunodeficiency virus (HIV) is associated with lower nitric oxide (NO) bioavailability and vascular dysfunction. Nitrate-rich beetroot juice (BJ) has been shown to acutely increase NO availability and vascular function in healthy and individuals at high risk for cardiovascular disease. Thus, we tested the effects of BJ ingestion on flow-mediated dilation (FMD) and pulse wave velocity (PWV) measurements in healthy and HIV-infected patients. Thirteen HIV-infected individuals (age, 36 ± 10 years) and 18 healthy (age, 27 ± 8 years) participated in the study. Individuals were submitted to vascular tests such as FMD and pulse PWV at pre (T0) and at 120 min (T120) after BJ and placebo (PLA) ingestion. The %FMD at T0 of the control group was significantly higher than the %FMD at T0 of the HIV individuals in both interventions. BJ improved the %FMD at T120 when compared with T0 in the HIV and control groups. There was no change in %FMD after PLA ingestion in the control and HIV groups. There were no differences between groups (control vs HIV), time points (T0 vs T120), and interventions (BJ vs PLA) for PWV. Our findings showed that nitrate-rich BJ ingestion acutely improved vascular function in healthy and HIV-infected patients. Clinical Trials Registry no. NCT03485248. Novelty: HIV is associated with lower NO bioavailability and vascular dysfunction. Acute supplementation with nitrate-rich BJ has been shown to acutely increases NO bioavailability. We showed for the first time that BJ acutely improves endothelial function in HIV-infected patients.
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Affiliation(s)
| | - Ana Paula Machado-Santos
- Nutrition and Exercise Metabolism Group, Federal University of Rio de Janeiro, Macaé, RJ 27900-000, Brazil
| | - Elisa Barros-Santos
- Nutrition and Exercise Metabolism Group, Federal University of Rio de Janeiro, Macaé, RJ 27900-000, Brazil
| | - Gustavo Vieira De Oliveira
- Nutrition and Exercise Metabolism Group, Federal University of Rio de Janeiro, Macaé, RJ 27900-000, Brazil
| | - Juan Manuel Murias
- Faculty of kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Thiago Silveira Alvares
- Nutrition and Exercise Metabolism Group, Federal University of Rio de Janeiro, Macaé, RJ 27900-000, Brazil
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Dietary nitrate improves skeletal muscle microvascular oxygenation in HIV-infected patients receiving highly active antiretroviral therapy: a randomised, double-blind, cross-over, placebo-controlled study. Br J Nutr 2020; 124:1277-1284. [PMID: 32576320 DOI: 10.1017/s0007114520002226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
HIV-1 proteins and highly active antiretroviral therapy (HAART) have been associated with microvascular endothelial dysfunction. Although nitrate-rich beetroot juice (NR-BJ) consumption has been shown to improve endothelial function in clinical population, its effects in HIV-infected patients has not been addressed. We investigated the effect of a single dose of NR-BJ on muscle oxygen saturation parameters in response to a handgrip exercise in HIV-infected patients. Fifteen HIV-infected patients received NR-BJ or nitrate-depleted beetroot juice (ND-BJ) in a double-blind cross-over design. Near-IR spectroscopy was utilised to assess muscle oxygen saturation parameters during rhythmic handgrip exercise after NR-BJ or ND-BJ supplementation. A significant faster muscle oxygen desaturation rate during exercise (-7·97 (sd 5·00) v. -5·45 (3·94) %/s, P = 0·005) and muscle oxygen resaturation rate during exercise recovery (0·43 (0·24) v. 0·28 (0·24) %/s, P = 0·030) after NR-BJ ingestion was found. However, no significant difference in exercise time until fatigue was observed. Salivary nitrite and urinary nitrate concentration were analysed after NR-BJ or ND-BJ. A significant increase in salivary nitrite and urinary nitrate in NR-BJ was observed compared with ND-BJ (P < 0·05). Our findings suggest that NR-BJ consumption may acutely improve muscle oxygen saturation during exercise and exercise recovery in HIV-infected patients undergoing HAART and who are expected to present microvascular damage. Thus, future studies investigating the chronic effects of NR-BJ are warranted to delineate a better nutritional strategy based on nitrate-rich foods.
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Hollstein T, Schumann F, Kassner U. [HIV and dyslipidemia - reasons and therapy]. MMW Fortschr Med 2020; 162:54-61. [PMID: 32583267 DOI: 10.1007/s15006-020-0015-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Tim Hollstein
- Obesity and Diabetes Clinical Research Section, National Institutes of Health/NIDDK, Phoenix, AZ, USA
| | - Friederike Schumann
- Klinik für Endokrinologie, Lipidambulanz, Charité Universitätsmedizin Berlin, Deutschland
| | - Ursula Kassner
- Medizinische Klinik für Endokrinologie und Stoffwechselmedizin, Charité - Universitäts- medizin Berlin, Augustenburger Platz 1, D-13353, Berlin, Deutschland.
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Near-infrared spectroscopy-derived muscle oxygen saturation during exercise recovery and flow-mediated dilation are impaired in HIV-infected patients. Microvasc Res 2020; 130:104004. [PMID: 32234365 DOI: 10.1016/j.mvr.2020.104004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 03/18/2020] [Accepted: 03/25/2020] [Indexed: 12/17/2022]
Abstract
Highly active antiretroviral therapy has been associated with the presence of endothelial dysfunction in HIV-infected patients, which may impair oxygen delivery to muscles during exercise and exercise recovery. Near-infrared spectroscopy (NIRS) has been used to assess muscle oxygen saturation (SmO2) kinetics during exercise in different clinical populations in order to evaluate the balance between oxygen delivery and utilization by muscles. However, studies assessing SmO2 in HIV-infected patients have not been conducted. Therefore, the aim of the study was to evaluate NIRS-derived SmO2 during rhythmic handgrip exercise and flow-mediated dilation (FMD) in HIV-infected patients (HIV) compared to non-HIV-infected controls (N-HIV). Eighteen HIV and 17 N-HIV individuals underwent FMD assessment by ultrasound. The subjects then performed one set of rhythmic handgrip exercise until fatigue at 30% maximal isometric voluntary contraction. SmO2 was measured during entire exercise and 2-min exercise 3recovery. Muscle oxygen resaturation rate (upslope of the SmO2 over 10 s of recovery) was calculated. A significant lower FMD (3.5 ± 1.7 vs 5.9 ± 1.5%, P < 0.001) and slower oxygen resaturation rate (0.78 ± 0.4 vs 1.14 ± 0.4%·s-1, P = 0.020) in HIV as compared to N-HIV group were observed. In conclusion, our findings demonstrated that HIV-infected patients had reduced FMD and impaired muscle oxygenation during exercise recovery compared to non-HIV individuals.
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Dominick L, Midgley N, Swart LM, Sprake D, Deshpande G, Laher I, Joseph D, Teer E, Essop MF. HIV-related cardiovascular diseases: the search for a unifying hypothesis. Am J Physiol Heart Circ Physiol 2020; 318:H731-H746. [PMID: 32083970 DOI: 10.1152/ajpheart.00549.2019] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although the extensive rollout of antiretroviral (ARV) therapy resulted in a longer life expectancy for people living with human immunodeficiency virus (PLHIV), such individuals display a relatively increased occurrence of cardiovascular diseases (CVD). This health challenge stimulated significant research interests in the field, leading to an improved understanding of both lifestyle-related risk factors and the underlying mechanisms of CVD onset in PLHIV. However, despite such progress, the precise role of various risk factors and mechanisms underlying the development of HIV-mediated CVD still remains relatively poorly understood. Therefore, we review CVD onset in PLHIV and focus on 1) the spectrum of cardiovascular complications that typically manifest in such persons and 2) underlying mechanisms that are implicated in this process. Here, the contributions of such factors and modulators and underlying mechanisms are considered in a holistic and integrative manner to generate a unifying hypothesis that includes identification of the core pathways mediating CVD onset. The review focuses on the sub-Saharan African context, as there are relatively high numbers of PLHIV residing within this region, indicating that the greater CVD risk will increasingly threaten the well-being and health of its citizens. It is our opinion that such an approach helps point the way for future research efforts to improve treatment strategies and/or lifestyle-related modifications for PLHIV.
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Affiliation(s)
- Leanne Dominick
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Natasha Midgley
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Lisa-Mari Swart
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Devon Sprake
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Gaurang Deshpande
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Ismail Laher
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa.,Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Danzil Joseph
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Eman Teer
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - M Faadiel Essop
- Centre for Cardio-metabolic Research in Africa, Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
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Lehmann MH, Lehmann JM, Erfle V. Nef-induced CCL2 Expression Contributes to HIV/SIV Brain Invasion and Neuronal Dysfunction. Front Immunol 2019; 10:2447. [PMID: 31681324 PMCID: PMC6803470 DOI: 10.3389/fimmu.2019.02447] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/01/2019] [Indexed: 12/26/2022] Open
Abstract
C-C motif chemokine ligand 2 (CCL2) is a chemoattractant for leukocytes including monocytes, T cells, and natural killer cells and it plays an important role in maintaining the integrity and function of the brain. However, there is accumulating evidence that many neurological diseases are attributable to a dysregulation of CCL2 expression. Acquired immune deficiency syndrome (AIDS) encephalopathy is a severe and frequent complication in individuals infected with the human immunodeficiency virus (HIV) or the simian immunodeficiency virus (SIV). The HIV and SIV Nef protein, a progression factor in AIDS pathology, can be transferred by microvesicles including exosomes and tunneling nanotubes (TNT) within the host even to uninfected cells, and Nef can induce CCL2 expression. This review focuses on findings which collectively add new insights on how Nef-induced CCL2 expression contributes to neurotropism and neurovirulence of HIV and SIV and elucidates why adjuvant targeting of CCL2 could be a therapeutic option for HIV-infected persons.
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Affiliation(s)
- Michael H Lehmann
- Institute of Virology, Technische Universität München, Munich, Germany.,Institute for Infectious Diseases and Zoonoses, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jonas M Lehmann
- Department of Informatics, Technische Universität München, Munich, Germany
| | - Volker Erfle
- Institute of Virology, Technische Universität München, Munich, Germany
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Chelvanambi S, Gupta SK, Chen X, Ellis BW, Maier BF, Colbert TM, Kuriakose J, Zorlutuna P, Jolicoeur P, Obukhov AG, Clauss M. HIV-Nef Protein Transfer to Endothelial Cells Requires Rac1 Activation and Leads to Endothelial Dysfunction Implications for Statin Treatment in HIV Patients. Circ Res 2019; 125:805-820. [PMID: 31451038 PMCID: PMC7009312 DOI: 10.1161/circresaha.119.315082] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
RATIONALE Even in antiretroviral therapy-treated patients, HIV continues to play a pathogenic role in cardiovascular diseases. A possible cofactor may be persistence of the early HIV response gene Nef, which we have demonstrated recently to persist in the lungs of HIV+ patients on antiretroviral therapy. Previously, we have reported that HIV strains with Nef, but not Nef-deleted HIV strains, cause endothelial proinflammatory activation and apoptosis. OBJECTIVE To characterize mechanisms through which HIV-Nef leads to the development of cardiovascular diseases using ex vivo tissue culture approaches as well as interventional experiments in transgenic murine models. METHODS AND RESULTS Extracellular vesicles derived from both peripheral blood mononuclear cells and plasma from HIV+ patient blood samples induced human coronary artery endothelial cells dysfunction. Plasma-derived extracellular vesicles from antiretroviral therapy+ patients who were HIV-Nef+ induced significantly greater endothelial apoptosis compared with HIV-Nef-plasma extracellular vesicles. Both HIV-Nef expressing T cells and HIV-Nef-induced extracellular vesicles increased transfer of cytosol and Nef protein to endothelial monolayers in a Rac1-dependent manner, consequently leading to endothelial adhesion protein upregulation and apoptosis. HIV-Nef induced Rac1 activation also led to dsDNA breaks in endothelial colony forming cells, thereby resulting in endothelial colony forming cell premature senescence and endothelial nitric oxide synthase downregulation. These Rac1-dependent activities were characterized by NOX2-mediated reactive oxygen species production. Statin treatment equally inhibited Rac1 inhibition in preventing or reversing all HIV-Nef-induction abnormalities assessed. This was likely because of the ability of statins to block Rac1 prenylation as geranylgeranyl transferase inhibitors were effective in inhibiting HIV-Nef-induced reactive oxygen species formation. Finally, transgenic expression of HIV-Nef in endothelial cells in a murine model impaired endothelium-mediated aortic ring dilation, which was then reversed by 3-week treatment with 5 mg/kg atorvastatin. CONCLUSIONS These studies establish a mechanism by which HIV-Nef persistence despite antiretroviral therapy could contribute to ongoing HIV-related vascular dysfunction, which may then be ameliorated by statin treatment.
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Affiliation(s)
| | | | - Xingjuan Chen
- Indiana University School of Medicine, Indianapolis, IN 46202
| | | | | | | | - Jithin Kuriakose
- Indiana University School of Medicine, Indianapolis, IN 46202
- Ulster University, Ulster, Northern Ireland, UK
| | | | - Paul Jolicoeur
- Institut de Recherches Cliniques de Montreal, Montreal, Canada
| | | | - Matthias Clauss
- Indiana University School of Medicine, Indianapolis, IN 46202
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Bush KNV, Teel JL, Watts JA, Gore RS, Alvarado G, Harper NL, Okulicz JF. Association of Endothelial Dysfunction and Antiretroviral Therapy in Early HIV Infection. JAMA Netw Open 2019; 2:e1913615. [PMID: 31626317 PMCID: PMC6813669 DOI: 10.1001/jamanetworkopen.2019.13615] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
IMPORTANCE Human immunodeficiency virus (HIV) infection is associated with increased cardiovascular disease (CVD) events. Endothelial dysfunction (EDF) is involved in CVD pathogenesis; however, EDF onset after HIV acquisition and the potential for reversibility with antiretroviral therapy (ART) have not been evaluated to date. OBJECTIVE To evaluate endothelial function with noninvasive reactive hyperemia index (RHI) in patients with early HIV infection at baseline and after ART initiation. DESIGN, SETTING, AND PARTICIPANTS Cohort study in which 61 members of the United States Air Force diagnosed with HIV infection from September 1, 2015, through September 30, 2017, were evaluated for baseline EDF. Natural log-transformed RHI values (lnRHI) of less than 0.51 and at least 0.51 were defined as abnormal and normal, respectively. The RHI interval changes were evaluated in a subgroup of 40 patients. Data were analyzed from September 30, 2017, through January 30, 2018. EXPOSURE Early HIV infection. MAIN OUTCOMES AND MEASURES Baseline EDF at HIV diagnosis and interval changes associated with ART initiation. RESULTS The 61 patients included in the analysis were predominantly male (58 [95%]) and mostly African American (35 [57%]), with a mean (SD) age of 28.1 (6.7) years at HIV diagnosis. Median time from estimated date of HIV seroconversion to RHI assessment was 10.6 months (interquartile range [IQR], 5.1-13.2 months), and the median CD4 lymphocyte count was 552/μL (IQR, 449/μL-674/μL). Patients had a mean (SD) body mass index of 26.2 (4.0), median (IQR) low-density lipoprotein cholesterol level of 97 (80-126) mg/dL, median (IQR) total cholesterol level of 163 (146-195) mg/dL, and no diabetes diagnoses. Overall mean (SD) lnRHI was 0.70 (0.29) at HIV diagnosis. Baseline RHI was normal in 47 patients (77%; mean [SD] lnRHI, 0.82 [0.20]) and was abnormal in 14 patients (23%; mean [SD] lnRHI, 0.30 [0.18]). Age (per 10-year increase) was not associated with an abnormal lnRHI (odds ratio, 2.15; 95% CI, 0.89-5.19; P = .09). Of the 41 patients with follow-up RHI assessments, 40 started ART immediately and repeated the RHI assessments at a median (IQR) of 6.4 (6.0-7.8) months. Use of ART was associated with an overall significan increase in mean (SD) lnRHI (0.13 [0.33]; P = .02). A greater increase in mean (SD) lnRHI was associated with abnormal (n = 11) compared with normal (n = 29) lnRHI at HIV diagnosis (0.33 [0.34]; P = .01 vs 0.04 [0.30]; P = .38). Among those with abnormal baseline lnRHI, 8 (73%) showed improved endothelial function after ART. The patient who declined ART converted from having a normal lnRHI (0.60) to an abnormal lnRHI (0.11) lnRHI after 8.3 months. CONCLUSIONS AND RELEVANCE In this study, EDF was common in early HIV infection, with associated reversal in most patients taking ART. Results suggest that persistent EDF and CVD complications may be associated with delayed ART. Further studies are necessary to define the role of noninvasive endothelial function testing in patients with HIV infection.
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Affiliation(s)
- Kelvin N. V. Bush
- Division of Cardiology, San Antonio Military Medical Center, San Antonio, Texas
| | - Julie L. Teel
- Division of Cardiology, San Antonio Military Medical Center, San Antonio, Texas
| | - James A. Watts
- Division of Cardiology, San Antonio Military Medical Center, San Antonio, Texas
| | - Rosco S. Gore
- Division of Cardiology, San Antonio Military Medical Center, San Antonio, Texas
| | - Gadiel Alvarado
- Infectious Disease Service, San Antonio Military Medical Center, San Antonio, Texas
| | - Nathan L. Harper
- Foundation for Advancing Veteran’s Health Research, San Antonio, Texas
| | - Jason F. Okulicz
- Infectious Disease Service, San Antonio Military Medical Center, San Antonio, Texas
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Ginsenoside Rb1 Blocks Ritonavir-Induced Oxidative Stress and eNOS Downregulation through Activation of Estrogen Receptor-Beta and Upregulation of SOD in Human Endothelial Cells. Int J Mol Sci 2019; 20:ijms20020294. [PMID: 30642080 PMCID: PMC6358897 DOI: 10.3390/ijms20020294] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 02/07/2023] Open
Abstract
We have previously shown that ritonavir (RTV), a highly active anti-retroviral therapy (HAART) drug, can cause endothelial dysfunction through oxidative stress. Several antioxidants including ginsenoside Rb1, a compound with antioxidant effect, can effectively block this side effect of RTV in endothelial cells. In the current study, we explored a mechanism by which ginsenoside Rb1 could protect these cells via binding of estrogen receptors (ERs). We found that several human endothelial cell lines differentially expressed ER-β and had very low levels of ER-α. RTV treatment significantly increased the production of reactive oxygen species (ROS) and decreased the expression of endothelial nitric oxidase synthase (eNOS) and superoxide dismutase (SOD) in HUVECs, while Rb1 effectively blocked these effects of RTV. These effects of Rb1 were effectively inhibited by silencing ER-β, indicating that ginsenoside Rb1 requires ER-β for its antioxidant activity in inhibiting the deleterious effect of RTV in human endothelial cells. Furthermore, Rb1 specifically activated ER-β transactivation activity by ER-β luciferase reporter assay. Rb1 competitively bound to ER-β, which was determined by the high sensitive fluorescent polarization assay.
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