Background:Because of factors only partly understood, the generalized elevated immune activation and inflammation characterizing HIV-1–infected patients are corrected incompletely with antiretroviral therapy (ART). Extracellular vesicles (EVs) including exosomes and microvesicles released by several cell types may contribute to immune activation and dysfunction. EV size, abundance, and content appear to differ according to infection phase, disease progression, and ART.Methods:We examined whether the size of EVs and the abundance of exosomes in plasma are associated with cell and tissue activation as well as with viral production. Acetylcholinesterase-bearing (AChE+) exosomes in plasma were quantified using an AChE assay. EV size was analyzed using dynamic light scattering. Proteins and microRNAs present in EVs were detected by Western blot and real-time polymerase chain reaction, respectively.Results:Exosomes were found more abundant in the plasma of ART-naive patients. EV size was larger in ART-naive than in ART-suppressed patients, elite controllers, or healthy control subjects. Both exosome abundance and EV sizes were inversely correlated with CD4/CD8 T-cell ratio and neutrophil, platelet, and CD4 T-cell counts and positively correlated with CD8 T-cell counts. A negative correlation was found between CD4 T-cell nadir and exosome abundance, but not EV size. Levels of miR-155 and miR-223 but not miR-92 were strongly correlated negatively with EV abundance and size in ART-naive patients.Conclusions:Monitoring of circulating EVs and EV-borne microRNA is possible and may provide new insight into HIV-1 pathogenesis, disease progression, and the associated inflammatory state, as well as the efficacy of ART and the treatments intended to reduce immune activation.

Purpose This study aimed to assess the cardiorespiratory response during a 1-min sit-to-stand test (1STS) in comparison with cycling cardiopulmonary exercise test (CPET) in people with chronic obstructive pulmonary disease (COPD) and in healthy subjects and to evaluate whether 1STS may induce leg fatigue in these individuals. Methods Fourteen people with severe COPD and 12 healthy subjects performed a 1STS and a CPET during which cardiorespiratory response, perception of dyspnea, and leg fatigue were assessed. Quadriceps strength was assessed before and after 1STS, and contractile fatigue was defined as a postexercise fall in quadriceps twitch force greater than 15% of resting values. Results In COPD, peak V˙O2, V˙E, and HR achieved during 1STS reached 113%, 103%, and 93% of the corresponding values during CPET, respectively. Decrease in SpO2 from preexercise to peak exercise and the magnitude of dynamic hyperinflation were similar between 1STS and CPET. Borg dyspnea and leg fatigue scores were higher for CPET than 1STS. In healthy subjects, peak cardiorespiratory demand and symptom scores were higher during CPET compared with 1STS. A V˙O2 overshoot during recovery was observed only in people with COPD. After 1STS, the V˙O2 half-time recovery of COPD was 152 ± 25 s compared with 74 ± 18 in healthy subjects (P < 0.01). Ten people with COPD and five healthy subjects were considered as fatiguers. Conclusion The 1STS induced a similar cardiorespiratory stress to that of CPET and was associated with contractile quadriceps fatigue in people with severe COPD. The V˙O2 overshoot and slower recovery time of cardiorespiratory variables seen in COPD demonstrate the clinical relevance of monitoring the recovery phase of exercise.

Purpose To assess the 1-min sit-to-stand test (1STS) test–retest reliability and construct validity and its associated cardiorespiratory response in comparison to the 6-min walk test (6MWT) and symptom-limited cycling cardiopulmonary exercise test (CPET) in people with interstitial lung disease (ILD). Methods Fifteen participants with ILD performed two 1STS tests, a 6MWT and a CPET. The three tests were administered on three separate visits, and cardiorespiratory parameters were continuously recorded during the tests. Results The number of repetitions during both 1STS tests was 22 ± 4 and 22 ± 4 (mean difference of 0.53 ± 2.00 repetitions, P = 0.32) with an intraclass correlation of 0.937 (95% confidence interval, 0.811–0.979]) and a minimal detectable change of 2.9 repetitions. The number of 1STS repetitions was highly correlated with the 6MWT distance (r = 0.823, P < 0.001) and with the peak cycling power output expressed in % predicted values (r = 0.706, P < 0.003). Oxygen consumption (V˙O2) peak during the 1STS reached 83% and 78% of V˙O2 peak during 6MWT and CPET, respectively. Peak 1STS HR, minute ventilation (V˙E,), V˙O2 values, as well as nadir SpO2 were achieved during the recovery phase of the test, whereas peak 6MWT and CPET HR, V˙E, V˙O2 and nadir SpO2 always occurred at the end of the test. The three tests elicited a similar fall in SpO2 ranging between 8% and 12%. Symptom scores after the 1STS were similar to those seen at the end of the 6MWT but lower than those of CPET. Conclusions The 1STS showed excellent test–retest reliability in patients with ILD in whom it elicited a substantial, but submaximal cardiorespiratory response. Our data also support the construct validity of the 1STS to assess functional exercise capacity in patients with ILD and to detect exercise-induced O2 desaturation.