Carnitine and cardiac interstitium.
An important part of (acyl)carnitine may be stored in interstitial spaces and the external surface of adjacent cells. A high concentration of carnitine in the direct vicinity of cells may enhance the synthesis and export of long-chain acylcarnitine. Long-chain acylcoenzyme A, from which long-chain acyl carnitine is formed, cannot penetrate intact cell membranes. During hypoperfusion or ischemia, when long-chain acylcoenzyme A accumulates due to hampered fatty acid oxidation, there is an increased formation of long-chain acyl carnitine which diffuses into the interstitium and adjacent vascular endothelial cells. Due to its lipophilic nature and net positive charge (limitation of carboxyl-group dissociation in ischemic acidosis), long-chain acyl carnitine may decrease the affinity of Ca2+ to the cell surface and prevent Ca2+ overload of cells. The advantage of carnitine over many other cationic amphiphiles in the protection of areas of ischemia is that long-chain acyl carnitine is formed and stored only in ischemic areas.
Hülsmann
W C
WC
Thoraxcenter, Erasmus University, Rotterdam, The Netherlands.
Peschechera
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A
Arrigoni-Martelli
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E
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism; D002331:Carnitine / Q000096:biosynthesis / Q000378:metabolism*; D006321:Heart / Q000502:physiology; D006801:Humans; D017202:Myocardial Ischemia / Q000503:physiopathology*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D051381:Rats
D015220:Calcium Channels; D002331:Carnitine; D010100:Oxygen