Changes in energy metabolism of calf muscle in patients with intermittent claudication assessed by 31P magnetic resonance spectroscopy: a phase II open study.
Energy status and metabolism in skeletal muscle of nine patients with peripheral arterial disease and suffering from intermittent claudication were evaluated using 31phosphorus magnetic resonance spectroscopy (MRS) before and after treatment for 3 months with propionyl-L-carnitine (PLC; 2 g/day p.o.). Maximum walking distance (MWD) was assessed on a standard treadmill (4 km/h, zero incline). For the group as a whole 31P MRS results did not change significantly with PLC. Although MWD increased by a mean of 36%, this change did not reach significance. However, when these variables were assessed with respect to the change in MWD, there were significant differences between those who increased MWD by > 30% (responders, R; n = 5) and those who did not (nonresponders, NR; n = 4). Compared with pretreatment values, during exercise the decrease in muscle pH in R relative to the decrease in phosphocreatine was less after PLC (p = 0.04). After exercise there was a significant inverse correlation between the changes in recovery half-time (t1/2) for phosphocreatine and in MWD (r = -0.91, p = 0.01). With PLC, Vmax increased in R (p = 0.04), but not in NR. For the patient group as a whole, the changes in Vmax and MWD correlated positively (r = 0.90, p = 0.01). This study helps to identify the changes in muscle metabolism that correlate with changes in exercise performance, and may accompany treatment with PLC.
Taylor
D J
DJ
MRC Biochemical and Clinical Magnetic Resonance Unit, Oxford Radcliffe Hospital Trust, UK.
Amato
A
A
Hands
L J
LJ
Kemp
G J
GJ
Ramaswami
G
G
Nicolaides
A
A
Radda
G K
GK
D000244:Adenosine Diphosphate / Q000097:blood; D000255:Adenosine Triphosphate / Q000097:blood; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002331:Carnitine / Q000031:analogs & derivatives / Q000627:therapeutic use; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D007866:Leg; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010725:Phosphocreatine / Q000097:blood; D010758:Phosphorus; D016138:Walking / Q000502:physiology
D010725:Phosphocreatine; C003223:propionylcarnitine; D010758:Phosphorus; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002331:Carnitine