Methyl-beta-cyclodextrin: an alternative carrier for intravenous infusion of palmitate during tracer studies in swine (Sus scrofa domestica)

Fatty acid-free albumin has been the standard carrier for intravenous infus ion of fatty acids to study in vivo lipid metabolism. However, subjects can have adverse reactions to infusion of albumin. We sought an alternative to albumin as a carrier for intravenous infusion of fatty acids, using the pi g as a model. Cyclodextrins are naturally occurring water-soluble molecules that can serve as carriers for lipid-soluble compounds. C-13-palmitate was complexed to either 20% methyl-beta -cyclodextrin, 20% 2-hydroxypropyl-bet a -cyclodextrin, or 5% porcine albumin (isotopic purity of infusates: 99.22 +/- 0.66%). C-13-palmitate-albumin was infused under fed conditions and C- 13-palmitate-methyl-beta -cyclodextrin was infused under fasted and fed con ditions in 50-kg pigs. Palmitate remained in solution at 4 degreesC in meth yl-beta -cyclodextrin, but precipitated at 25-30 degreesC in 2-hydroxypropy l-beta -cyclodextrin. Pigs infused with C-13-palmitate-methyl-beta -cyclode xtrin maintained normal body temperature and appetite, those infused with C -13-palmitate-albumin became anorexic and exhibited other negative side eff ects to albumin. Palmitate oxidation rates under fed conditions were simila r using either C-13-palmitate-methyl-beta -cyclodextrin or C-13-palmitate-a lbumin complexes. Fasting increased C-13-palmitate-methyl-beta -cyclodextri n oxidation by approximately eight-fold. These data suggest that methyl-bet a -cyclodextrin may be a suitable substitute for albumin in fatty acid meta bolism studies in swine. (C) 2001 Published by Elsevier Science Inc.