Mitochondrial Dysfunction of Human Muscle in Chronic Alcoholism Detected by Using ³¹P‐Magnetic Resonance Spectroscopy and Near‐Infrared Light Absorption

Abstract

We previously examined the effect of alcohol on muscle energy metabolism in chronic alcoholics by using 31 P-magnetic resonance spectroscopy. Measurements of intracellular pH and PCr index [PCr/ (PCr + Pi)] during resting, hand grasping, and recovery in the left flexor digitorum superficialis muscle of alcoholics with neurological signs showed a marked decrease and delayed recovery of pH, but rapid recovery of PCr index indicating that the muscle produces lactate during and after exercise to maintain the ATP level. To clarify the reason for this preference for anaerobic metabolism, we conducted simultaneous measurements of the muscle blood supply during and after exercise by using the near-infrared light method and energy metabolism by using 31 P-magnetic resonance spectroscopy. In alcoholics with neurological signs, we observed a significant increase of oxyhemoglobin after exercise with a slight increase of total hemoglobin. In healthy volunteers and chronic alcoholics without neurological signs, such an overshoot of oxyhemoglobin was not observed. We conclude that chronic alcoholics with neurological signs have an abnormality of aerobic metabolism owing to muscle mitochondrial dysfunction.

Muscle metabolism in patients with polymyositis simultaneously evaluated by using 31P-magnetic resonance spectroscopy and near-infrared spectroscopy

“…Wavelengths of 780, 805 and 880 nm were used for observation, for a total of 24 min. Percentage changes in absorption per second were expressed as Dabs1, Dabs2 and Dabs3, and intramuscular oxy-Hb, deoxy-Hb and total Hb were calculated according to Eqns (3)(4)(5):…”

“…The use of 31 P-MRS enables us to obtain information on high-energy phosphates, such as ATP and phosphocreatine (PCr), phospholipid metabolites, such as phosphomonoesters and phosphodiesters, and phosphorylated substances, such as inorganic phosphate (Pi), in muscle (2,3). There have already been many reports on the kinetics of these substances in patients with neurological diseases, including cerebral ischaemia and brain tumours, whereas less information is available on muscular metabolism as determined by simultaneous 31 P-MRS and near-infrared spectroscopy (NIRS) in patients with neuromuscular diseases (4). If a patient has an energy metabolism disorder or a blood circulation disorder as an underlying disease, it is possible to use an exercise test to establish the kinetics of energy metabolism.…”