Background Circulating microparticles have emerged as biomarkers and effectors of vascular disease. Elevated rates of cardiovascular disease are seen in HIV ‐1–seropositive individuals. The aims of this study were to determine: (1) if circulating microparticles are elevated in antiretroviral therapy–treated HIV ‐1–seropositive adults; and (2) the effects of microparticles isolated from antiretroviral therapy –treated HIV ‐1–seropositive adults on endothelial cell function, in vitro. Methods and Results Circulating levels of endothelial‐, platelet‐, monocyte‐, and leukocyte‐derived microparticles were determined by flow cytometry in plasma from 15 healthy and 15 antiretroviral therapy–treated, virologically suppressed HIV ‐1–seropositive men. Human umbilical vein endothelial cells were treated with microparticles from individual subjects for 24 hours; thereafter, endothelial cell inflammation, oxidative stress, senescence, and apoptosis were assessed. Circulating concentrations of endothelial‐, platelet‐, monocyte‐, and leukocyte‐derived microparticles were significantly higher (≈35%–225%) in the HIV ‐1–seropositive compared with healthy men. Microparticles from HIV ‐1–seropositive men induced significantly greater endothelial cell release of interleukin‐6 and interleukin‐8 (≈20% and ≈35%, respectively) and nuclear factor‐κB expression while suppressing anti‐inflammatory microRNAs (miR‐146a and miR‐181b). Intracellular reactive oxygen species production and expression of reactive oxygen species –related heat shock protein 70 were both higher in cells treated with microparticles from the HIV ‐1–seropositive men. In addition, the percentage of senescent cells was significantly higher and sirtuin 1 expression lower in cells treated with HIV ‐1–related microparticles. Finally, caspase‐3 was significantly elevated by microparticles from HIV ‐1–seropositive men. Conclusions Circulating concentrations of endothelial‐, platelet‐, monocyte‐, and leukocyte‐derived microparticles were higher in antiretroviral therapy–treated HIV ‐1–seropositive men and adversely affect endothelial cells promoting cellular inflammation, oxidative stress, senescence, and apoptosis. Circulating microparticles may contribute to the vascular risk associated with HIV ‐1 infection.

The aim of this study was to determine, in vitro, the effects of X4 and R5 HIV‐1 gp120 and Tat on: (1) endothelial cell senescence and (2) endothelial cell microRNA (miR) expression. Endothelial cells were treated with media without and with: R5 gp120 (100 ng/mL), X4 gp120 (100 ng/mL), or Tat (500 ng/mL) for 24 h and stained for senescence‐associated β‐galactosidase (SA‐β‐gal). Cell expression of miR‐34a, miR‐217, and miR‐146a was determined by RT‐PCR. X4 and R5 gp120 and Tat significantly increased (~100%) cellular senescence versus control. X4 gp120 significantly increased cell expression of miR‐34a (1.60 ± 0.04 fold) and miR‐217 (1.52 ± 0.18), but not miR‐146a (1.25 ± 0.32). R5 gp120 significantly increased miR‐34a (1.23 ± 0.07) and decreased miR‐146a (0.56 ± 0.07). Tat significantly increased miR‐34a (1.49 ± 0.16) and decreased miR‐146a (0.55 ± 0.23). R5 and Tat had no effect on miR‐217 (1.05 ± 0.13 and 1.06 ± 0.24; respectively). HIV‐1 gp120 (X4 and R5) and Tat promote endothelial cell senescence and dysregulation of senescence‐associated miRs.

The experimental aim of this study was to determine the effects of high glucose-induced endothelial microparticles (EMPs) on endothelial cell susceptibility to apoptosis. Human umbilical vein endothelial cells (HUVECs) were cultured (3rd passage) and plated in 6-well plates at a density of 5.0 × 105 cells/condition. Cells were incubated with media containing 25mM D-glucose (concentration representing a diabetic glycemic state) or 5mM D-glucose (normoglycemic condition) for 48 h to generate EMPs. EMP identification (CD144+ expression) and concentration was determined by flow cytometry. HUVECs (3×106 cells/condition) were treated with EMPs generated from either the normal or high glucose conditions for 24 h. Intracellular concentration of active caspase-3 was determined by enzyme immunoassay. Cellular expression of miR-Let7a, an anti-apoptotic microRNA, was determined by RT-PCR using the ΔΔCT normalized to RNU6. High glucose-derived EMPs significantly increased both basal (1.5±0.1 vs 1.0±0.1 ng/mL) and staurosporine-stimulated (2.2±0.2 vs 1.4±0.1 ng/mL) active caspase-3 compared with normal glucose EMPs. Additionally, the expression of miR-Let-7a was markedly reduced (~140%) by high glucose EMPs (0.43±0.17 fold vs control). These results demonstrate that hyperglycemic-induced EMPs increase endothelial cell active caspase-3. This apoptotic effect may be mediated, at least in part, by a reduction in miR-Let-7a expression.