Impaired oxygen uptake efficiency slope and off-transient kinetics of pulmonary oxygen uptake in sickle cell anemia are associated with hemorheological abnormalities

Article type: Research Article

Authors: Charlot, Keyne^{a; b; c} | Waltz, Xavier^{a; b; c} | Hedreville, Mona^{a; d} | Sinnapah, Stéphane^a | Lemonne, Nathalie^e | Etienne-Julan, Maryse^{c; e} | Soter, Valérie^f | Hue, Olivier^a | Hardy-Dessources, Marie-Dominique^{b; c} | Connes, Philippe^{b; c; g; *}

Affiliations: [a] Laboratory ACTES (EA 3596), Department of Physiology, French West Indies and Guiana University, Pointe-à-Pitre, Guadeloupe, France | [b] UMR Inserm U1134, French West Indies and Guiana University, Pointe-à-Pitre, Guadeloupe, France | [c] Laboratoire d’Excellence du Globule Rouge (LABEX GR-Ex), PRES Sorbonne, Paris, France | [d] Emergency Care Department, Academic Hospital of Pointe-à-Pitre, Pointe-à-Pitre, Guadeloupe, France | [e] Sickle cell Center, Academic Hospital of Pointe-à-Pitre, Pointe-à-Pitre, Guadeloupe, France | [f] Direction of Research and Innovation, Academic Hospital of Pointe-à-Pitre, Pointe-à-Pitre, Guadeloupe, France | [g] Institut Universitaire de France (IUF), Paris, France

Correspondence: [*] Corresponding author: Philippe Connes, UMR Inserm U1134, French West Indies and Guiana University, Pointe-à-Pitre, Guadeloupe, France. Tel.: +33 590 590 83 48 99; Fax: +33 590 590 83 05 13; pconnes@yahoo.fr

Abstract: Oxygen uptake efficiency slope (OUES) and excess post-exercise oxygen consumption (EPOC) are markers of physical fitness in the general population but have never been characterized in sickle cell anemia (SCA) where hematological and hemorheological properties are severely altered. Eight SCA patients and eleven healthy subjects (CONT) performed a submaximal incremental exercise conducted until the first ventilatory threshold (VT1). OUES was calculated from the data collected during the incremental period and EPOC parameters (amplitude [A] and time constant [τ]) were calculated from the data measured during exercise recovery. We found that OUES (p = 0.007) and A (p = 0.010) were lower, and τ (p = 0.035) was higher, in SCA patients compared to CONT subjects. OUES and τ were significantly correlated with hematocrit, red blood cell (RBC) deformability and RBC aggregates strength. Our findings suggest that both the abilities to use oxygen during exercise and to recover after a physical activity are impaired in SCA patients. This poor physical fitness seems to depend on the degree of anemia and RBC rheological alterations.

Keywords: Physical activity, sickle cell disease, hemorheology, physical fitness, exercise recovery

DOI: 10.3233/CH-141891

Journal: Clinical Hemorheology and Microcirculation, vol. 60, no. 4, pp. 413-421, 2015