TY - JOUR
T1 - Altered glutamate metabolism is associated with reduced muscle glutathione levels in patients with emphysema
AU - Engelen, M.P.K.J.
AU - Schols, A.M.W.J.
AU - Does, J.
AU - Deutz, N.E.P.
AU - Wouters, E.F.M.
PY - 2000/1/1
Y1 - 2000/1/1
N2 - Chronic obstructive pulmonary disease (COPD) is often characterized by an impaired skeletal muscle energy metabolism, which is at least partly related to chronic hypoxia and a reduced diffusing capacity. We have found that muscle glutamate (Glu), which is negatively influenced by these conditions, was reduced in patients with severe COPD. The aim of this study was to investigate whether the reduced intracellular Glu level in patients with emphysema is associated with an increased muscle glycolytic metabolism Since Glu is an important substrate in the synthesis of glutamine (Gln) and glutathione (GSH), the influence of Glu status on muscle GSH and Gln was also examined. In 13 patients with emphysema and 25 control patients, arterial blood and biopsies from the vastus lateralis muscle were obtained. Expressed as a percentage of the control values, the patients with emphysema had reduced values for muscle Glu (64 +/- 12%; p <0.001), GSH (76 +/- 23%; p <0.01), and Gln (93 +/- 5%; p <0.01), and higher values for lactate (p <0.01) and pyruvate (p <0.05). No differences were found in plasma values. Muscle Glu was highly associated with GSH (R-2 = 0.61; P <0.001), but not with Gln. This study illustrates that reduced Glu levels in skeletal muscle of patients with emphysema are possibly related to an enhanced glycolytic activity and associated with decreased GSH levels.
AB - Chronic obstructive pulmonary disease (COPD) is often characterized by an impaired skeletal muscle energy metabolism, which is at least partly related to chronic hypoxia and a reduced diffusing capacity. We have found that muscle glutamate (Glu), which is negatively influenced by these conditions, was reduced in patients with severe COPD. The aim of this study was to investigate whether the reduced intracellular Glu level in patients with emphysema is associated with an increased muscle glycolytic metabolism Since Glu is an important substrate in the synthesis of glutamine (Gln) and glutathione (GSH), the influence of Glu status on muscle GSH and Gln was also examined. In 13 patients with emphysema and 25 control patients, arterial blood and biopsies from the vastus lateralis muscle were obtained. Expressed as a percentage of the control values, the patients with emphysema had reduced values for muscle Glu (64 +/- 12%; p <0.001), GSH (76 +/- 23%; p <0.01), and Gln (93 +/- 5%; p <0.01), and higher values for lactate (p <0.01) and pyruvate (p <0.05). No differences were found in plasma values. Muscle Glu was highly associated with GSH (R-2 = 0.61; P <0.001), but not with Gln. This study illustrates that reduced Glu levels in skeletal muscle of patients with emphysema are possibly related to an enhanced glycolytic activity and associated with decreased GSH levels.
U2 - 10.1164/ajrccm.161.1.9901031
DO - 10.1164/ajrccm.161.1.9901031
M3 - Article
C2 - 10619804
SN - 1073-449X
VL - 161
SP - 98
EP - 103
JO - American Journal of Respiratory and Critical Care Medicine
JF - American Journal of Respiratory and Critical Care Medicine
IS - 98
ER -