This study shows that in CHF PDE(5) inhibition modulates pulmonary pressure and vascular tone, and improves DLco, exercise peak VO(2), aerobic (DeltaVO(2)/DeltaWR) and ventilatory (VE/VCO(2) slope) efficiencies, and oxygen debt (recovery tau). Endothelial mechanisms may underlie these effects.

Objective-Regulatory T (Treg) cells play a protective role in experimental atherosclerosis. In the present study, we investigated whether the levels of circulating Treg cells relate to the degree of atherosclerosis in carotid and coronary arteries. Methods and Results-We studied 2 distinct populations: (1) 113 subjects, selected from a free-living population (carotid study), in which we measured the intima-media thickness of the common carotid artery, as a surrogate marker of initial atherosclerosis; and (2) 75 controls and 125 patients with coronary artery disease (coronary study): 36 with chronic stable angina, 50 with non-ST-elevation acute coronary syndrome, 39 with ST-elevation acute myocardial infarction. Treg-cell levels were evaluated by flow cytometry (Treg cells identified as CD3 ϩ CD4 ϩ CD25 high CD127 low ) and by mRNA expression of forkhead box P3 or of Treg-associated cytokine interleukin 10. In the carotid study, no correlation was observed between Treg-cell levels and intima-media thickness. No differences in Treg-cell levels were observed comparing rapid versus slow intima-media thickness progressors from a subgroup of patients (nϭ65), in which prospective data on 6-year intima-media thickness progression were available. In the coronary group, Treg-cell levels were not altered in chronic stable angina patients. In contrast, nonunivocal variations were observed in patients suffering an acute coronary syndrome (with a Treg-cell increase in ST-elevation acute myocardial infarction and a Treg-cell decrease in non-ST-elevation acute coronary syndrome patients). Key Words: regulatory T cells Ⅲ coronary artery disease Ⅲ flow cytometry Ⅲ carotid artery intima-media thickness Ⅲ acute coronary syndrome T cells play a role in atherosclerosis and in acute manifestation of plaque destabilization. 1 The activation of inflammatory pathways in atherosclerosis and in coronary artery disease (CAD) is not confined to coronary lesions but involves the activation of neutrophils, monocytes, and lymphocytes (ie, CD69 Conclusion-Theϩ , HLA-DR ϩ , and CD 137 ϩ T cells) in peripheral blood in particular during acute coronary syndromes (ACSs). [2][3][4] On the other hand, regulatory T (Treg) cells reduce the development of experimental atherosclerosis acting both systemically and within the lesion. 5,6 Immunostaining of human atherosclerotic plaques showed that Treg cells are present during all stages of plaque development in the intima and adventitia. 7 In general, Treg cells play a key role in the maintenance of immunologic self-tolerance and negative control of a variety of pathological immune responses. 8 Several subsets of Treg cells with distinct phenotypes and distinct mechanisms of action have been described (see Sakaguchi et al,8 Roncarolo et al, 9 and O'Garra and Vieira 10 for review). Treg cells mediate the immunoregulatory function by producing cytokines, such as interleukin (IL)-10 and See accompanying article on page 1679 ϩ Treg cells, which have increased ability of homing and trafficking to inflamed nonly...

Chronic heart failure (CHF) may impair lung gas diffusion, an effect that contributes to exercise limitation. We investigated whether diffusion improvement is a mechanism whereby physical training increases aerobic efficiency in CHF. Patients with CHF (n = 16) were trained (40 min of stationary cycling, 4 times/wk) for 8 wk; similar sedentary patients (n = 15) were used as controls. Training increased lung diffusion (DlCO, +25%), alveolar-capillary conductance (DM, +15%), pulmonary capillary blood volume (VC, +10%), peak exercise O2 uptake (peak VO2, +13%), and VO2 at anaerobic threshold (AT, +20%) and decreased the slope of exercise ventilation to CO2 output (VE/VCO2, -14%). It also improved the flow-mediated brachial artery dilation (BAD, from 4.8 +/- 0.4 to 8.2 +/- 0.4%). These changes were significant compared with baseline and controls. Hemodynamics were obtained in the last 10 patients in each group. Training did not affect hemodynamics at rest and enhanced the increase of cardiac output (+226 vs. +187%) and stroke volume (+59 vs. +49%) and the decrease of pulmonary arteriolar resistance (-28 vs. -13%) at peak exercise. Hemodynamics were unchanged in controls after 8 wk. Increases in DlCO and DM correlated with increases in peak VO2 (r = 0.58, P = 0.019 and r = 0.51, P = 0.04, respectively) and in BAD (r = 0.57, P < 0.021 and r = 0.50, P = 0.04, respectively). After detraining (8 wk), DlCO, DM, VC, peak VO2, VO2 at AT, VE/VCO2 slope, cardiac output, stroke volume, pulmonary arteriolar resistance at peak exercise, and BAD reverted to levels similar to baseline and to levels similar to controls. Results document, for the first time, that training improves DlCO in CHF, and this effect may contribute to enhancement of exercise performance.

In patients with HF, left atrial volume, mitral deformation, and mitral regurgitant orifice correlated with pulmonary pressure at rest, whereas dynamic MR and limited contractile reserve correlated with pulmonary pressure at exercise. The magnitude of pulmonary pressure during exercise in these patients mainly depends on dynamic MR.