Faster lactate transport across red blood cell membrane in sickle cell trait carriers.
The physical and physiological behavior of sickle cell trait carriers (AS) is somewhat equivocal under strenuous conditions, although this genetic abnormality is generally considered to be a benign disorder. The occurrence of incidents and severe injuries in AS during exercise might be explained, in part, by the lactic acidosis due to a greater lactate influx into AS red blood cells (RBCs). In the present study, the RBC lactate transport activity via the different pathways was compared between AS and individuals with normal hemoglobin (AA). Sixteen Caribbean students, nine AS and seven AA, performed a progressive and maximal exercise test to determine maximal oxygen consumption. Blood samples were obtained at rest to assess haematological parameters and RBC lactate transport activity. Lactate influxes [total lactate influx and monocarboxylate transporter (MCT-1)-mediated lactate influx] into erythrocytes were measured at four external [14C]-labeled lactate concentrations (1.6, 8.1, 41, and 81.1 mM). The two groups had similar maximal oxygen consumption. Total lactate influx and lactate influx via the MCT-1 pathway were significantly higher in AS compared with AA at 1.6, 41, and 81.1 mM. The maximal lactate transport capacity for MCT-1 was higher in AS than in AA. Although AS and AA had the same maximal aerobic physical fitness, the RBCs from the sickle cell trait carriers took up more lactate at low and high concentrations than the RBCs from AA individuals. The higher MCT-1 maximal lactate transport capacity found in AS suggests greater content or greater activity of MCT-1 in AS RBC membranes.
Sara
Fagnété
F
Laboratoire Adaptation au Climat Tropical, Exercice et Société Unité Propre de Recherche de l'Enseignment Supérieur-Equipe d'Accueil 3596, Université des Antilles et de la Guyane, Campus de Fouillole, Pointe-à- Pitre Cedex, Guadeloupe.
Fagnété
Sara
S
Connes
Philippe
P
Philippe
Connes
C
Hue
Olivier
O
Olivier
Hue
H
Montout-Hedreville
Mona
M
Mona
Montout-Hedreville
MH
Etienne-Julan
Maryse
M
Maryse
Etienne-Julan
EJ
Hardy-Dessources
Marie-Dominique
MD
Marie-Dominique
Hardy-Dessources
HD
D000328:Adult; D004910:Erythrocyte Membrane / Q000378:metabolism*; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism*; D010101:Oxygen Consumption; D012805:Sickle Cell Trait / Q000097:blood*; D027981:Symporters / Q000378:metabolism*; D000099233:Monocarboxylate Transport Protein 1
D019344:Lactic Acid; D027501:Monocarboxylic Acid Transporters; D027981:Symporters; D000099233:Monocarboxylate Transport Protein 1