Morphometric evidence of the trophic effect of L-carnitine on human skeletal muscle.
We investigated the effect of long-term i.v. administration of L-carnitine on human muscle fibers using morphometric parameters. We administered 2g/day L-carnitine to patients undergoing hemodialysis for at least 12 months. At the end of this period a marked increase in serum and muscle carnitine levels was observed in all patients, together with hypertrophy and predominance of type 1 fibers. L-carnitine was withheld for 4 months, during which time serum and muscle levels gradually decreased and no changes were observed in muscle fibers. Subsequent addition of L-carnitine to dialysis fluid for another 4 months stabilized lower levels. At the end of this period reduction of diameter of type 1 fibers was observed. Type 2 fibers remained unchanged. Moreover, type 1 fibers remained predominant in all cases. Hence, we suggest that carnitine has a specific trophic effect on type 1 fibers which are characterized by an oxidative metabolism.
Spagnoli
L G
LG
Cattedra di Anatomia Patologica, II Università di Roma 'Tor Vergata', Italy.
Palmieri
G
G
Mauriello
A
A
Vacha
G M
GM
D'Iddio
S
S
Giorcelli
G
G
Corsi
M
M
D000368:Aged; D002331:Carnitine / Q000172:deficiency / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D006435:Renal Dialysis / Q000009:adverse effects; D014511:Uremia / Q000378:metabolism / Q000473:pathology / Q000628:therapy
D002331:Carnitine