Effects of intralipid-induced hypertriglyceridemia on plasma high-density lipoprotein metabolism in the cynomolgus monkey

Lipid-stimulated somatostatin secretion in rainbow trout,Oncorhynchus mykiss

Previous work has shown that somatostatins (SS) affect teleost lipid metabolism indirectly by inhibition of insulin (INS) and directly by stimulation of hepatic lipolysis. In the present study, rainbow trout (Oncorhynchus mykiss) were used to characterize further the lipid-SS relationship by evaluating how lipid, contributes to SS secretion bothin vivo andin vitro. In vivo hyperlipidemia was induced for up to 3 h by short-term (2 min) infusion of a triacylglycerol (TG)-rich lipid emulsion (20% Intralipid(®)). Plasma total lipid concentration increased 118 and 155% over control levels 1 h and 3 h, respectively, after infusion; much of this increase was due to elevated plasma fatty acids (FA), which increased 39 and 520%, respectively, over the same time-frame. The hyperlipidemic pattern was attended by a significant increase in the plasma concentration of SS. The specific effects of fatty acids were evaluated on isolated Brockmann bodies. Palmitic acid and oleic acid stimulated SS release 378 and 82%, respectively, over baseline levels. These results indicate that lipids, and in particular fatty acids, modulate SS secretion in rainbow trout.

Concentrations in serum and distribution in tissue of free and liposomal amphotericin B in rats during continuous intralipid infusion

The influences of Intralipid (IL) and 0.45% normal-saline infusions on the concentration in serum and distribution in tissue of amphotericin B (AmpB) and liposomal amphotericin B (L-AmpB) in rats were compared. In animals receiving a continuous IL infusion, concentrations of AmpB in kidneys and lungs were significantly higher, but the concentration of AmpB in serum was significantly lower in animals administered AmpB versus those given L-AmpB. In animals receiving a continuous normal-saline infusion concentrations of AmpB in kidneys and the spleen were significantly higher, but the concentration of AmpB in serum was significantly lower in animals administered AmpB versus those given L-AmpB. These results suggest that the increased total serum cholesterol and high-density lipoprotein cholesterol during the IL infusion decreased the clearance of AmpB from the bloodstream and decreased the L-AmpB concentration in the kidney and lung.

Modification of amphotericin B's therapeutic index by increasing its association with serum high-density lipoproteins

AmpB remains one of the drugs of choice in the treatment of systemic fungal infection; however, its therapy is limited by the development of renal toxicity. When AmpB was incorporated into negatively charged liposomes composed of DMPC and DMPG (L-AmpB), it was less toxic but as effective as free AmpB. However, the mechanism of L-AmpB's enhanced therapeutic index remains unknown. We have demonstrated that AmpB predominantly associates with HDL when incorporated into positively and negatively charged liposomes. To further understand the therapeutic importance of AmpB predominantly associating with HDL, we next examined the influence of lipoproteins on the antifungal activity and renal cytotoxicity of AmpB. The antifungal activity of AmpB and L-AmpB was not altered in the presence of HDL or LDL. The reduced nephrotoxicity associated with the use of L-AmpB, however, was related to a decreased uptake of AmpB by renal cells when AmpB was associated with HDL, and it may be a result of the low expression of HDL receptors in the LLC PK1 renal cells.