Serum extracellular vesicles expressing bone activity markers associate with bone loss after HIV antiretroviral therapy

Abstract

Objective: We tested whether bone-related extracellular vesicle phenotypes changed after initiating antiretroviral therapy (ART) and determined whether changes in levels of extracellular vesicles correlated with changes in bone mineral density (BMD). Design: Extracellular vesicle phenotypes were measured in blinded serum samples from 15 adults with HIV at baseline, 1, 3, 6 and 12 months after ART initiation. Not all samples were available at each time point so we averaged early (TP1, 1–3 months) and late (TP2, 6–12 months) time points. Methods: Extracellular vesicles were stained for osteocalcin (OC), RANKL (CD254), RANK (CD265), M-CSF (macrophage colony stimulating factor), and CD34. Serum OC, procollagen type I N-terminal propeptide (P1NP), and C-terminal telopeptide of type 1 collagen (CTx) were also measured. Results: BMD significantly decreased from baseline to 12 months. Levels of OC+EVs, serum OC, serum P1NP, and CTx were significantly higher at early and late time points compared with baseline. Increases in EVs expressing OC, RANKL, RANK, and CD34 from baseline to TP1 were associated with decreases in total hip BMD from baseline to 12 months. Change in serum OC, P1NP, and CTx from baseline to TP1 or TP2 did not correlate with change in BMD. Conclusion: Early changes in extracellular vesicles expressing markers of bone activity were associated with total hip bone loss 12 months after ART initiation. These data suggest that serum extracellular vesicles may serve as novel biomarkers of bone remodeling. Future studies are required to determine if extracellular vesicles contribute to the effects of ART on changes in bone turnover markers and BMD.

Comparative Analysis of Extracellular Vesicles in Patients with Severe and Mild Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

“…Of note, the two largest studies also were discrepant as to whether EV concentration differed in the plasma of healthy subjects compared to ME/CFS patients. Some of this variability may be due to the technique used to count EVs, which included nanoparticle tracking analysis (7,10,11) and flow cytometry (15). In the current study, EVs were quantitated by flow cytometry, and our finding of no difference in EV counts between clinical groups differed from the work of Eguchi et al (8).…”

“…In the current study, EVs were quantitated by flow cytometry, and our finding of no difference in EV counts between clinical groups differed from the work of Eguchi et al (8). The novelty of our EV analysis compared with prior studies in ME/CFS patients was the identification of the cell phenotype of origin of circulating EVs (15,17). Although we did not observe a difference in the levels of EV between ME/CFS participants by the severity of illness and the healthy controls, a significant difference was found in the EV cellular linage markers.…”

“…Samples were acquired on an LSR II flow cytometer (BD). Samples were collected for 60 seconds, and EV counts were calculated using TruCount tubes (BD Biosciences), which allowed normalization of the flow rate using the known amount of fluorescent beads in the TruCount tube (15). EV gates were set using polystyrene beads ranging from 100 nm to 1 mm (Sperhotech and Megamix beads).…”

Plasma CD16 + Extracellular Vesicles Associate with Carotid Artery Intima-Media Thickness in HIV + Adults on Combination Antiretroviral Therapy

“…The FSC and SSC detectors were set to a triggering threshold of 200 to minimize machine noise. Gates were established using 0.1-μm (Invitrogen) to 1-μm beads (Megamix, 0.16, 0.2, 0.24, and 0.5 μm; Spherotech, 1 μm) ( 14 , 49 ). Samples were acquired for 60 s at a low flow rate (8 to 12 μL/min).…”

“…Extracellular vesicles (EVs) have emerged as important mediators in cell-cell communication ( 14 , 15 ). EVs are derived from parent cells and represent a heterogeneous population, including microvesicles that bud from the cell membrane and exosomes that have endosomal/intracellular organelle origin ( 16 ).…”