Abstract-Hyperlipidemia may complicate the use of HIV protease inhibitors (PIs) in AIDS therapy. To determine the cause of hyperlipidemia, the effect of PIs on lipid metabolism was examined with HepG2 liver cells and AKR/J mice. In HepG2 cells, the PIs ABT-378, nelfinavir, ritonavir, and saquinavir stimulated triglyceride synthesis; ritonavir increased cholesterol synthesis; and amprenavir and indinavir had no effect. Moreover, nelfinavir increased mRNA expression of diacylglycerol acyltransferase and fatty acid synthase. The retinoid X receptor agonist LG100268, but not the antagonist LG100754, further increased PI-stimulated triglyceride synthesis and mRNA expression of fatty acid synthase in vitro. In fed mice, nelfinavir or ritonavir did not affect serum glucose and cholesterol, whereas triglyceride and fatty acids increased 57% to 108%. In fasted mice, ritonavir increased serum glucose by 29%, cholesterol by 40%, and triglyceride by 99%, whereas nelfinavir had no effect, suggesting these PIs have different effects on metabolism. Consistent with the in vitro results, nelfinavir and ritonavir increased triglyceride 2-to 3-fold in fasted mice injected with Triton WR-1339, an inhibitor of triglyceride clearance. We propose that PI-associated hyperlipidemia is due to increased hepatic triglyceride synthesis and suggest that retinoids or meal restriction influences the effects of select PIs on lipid metabolism. HAART has been associated with numerous affects on lipid metabolism, including subcutaneous fat wasting, abdominal obesity, insulin resistance, and hyperlipidemia. 2,3 Metabolic complications arising from HAART may be due to drug-drug interactions, exacerbation of preexisting conditions, reconstitution of immune system function, or a combination. 2,3 Studies of hyperlipidemia in HIV-infected persons are complicated because dyslipidemia may occur in the absence of therapy (reviewed in Safrin and Grunfeld 3 ). Although HIV infection itself and treatment with reverse transcriptase inhibitors have been associated with altered metabolism, 2-6 substantial evidence indicates a role for some PIs in causing metabolic complications.PIs are important therapeutically because they inhibit virus release from infected cells, reducing virus proliferation and subsequent infection. 7 The currently available PIs include amprenavir (APV), indinavir (IDV), nelfinavir (NFV), ritonavir (RTV), saquinavir (SQV), and ABT-378 (lopinavir; delivered in combination with RTV to enhance systemic exposure to ABT-378). The antiviral activity among individual PIs is variable and correlates with the ability to inhibit the HIV protease (ie, IC 50 0.10 to 20 nmol/L). Although these drugs contain a synthetic analog of the phenylalanine-proline amino acid sequence cleaved by the HIV protease, structural differences result in unique resistance and metabolic effects for each PI. 7 Initial reports in 1997 indicated that a number of patients developed hyperlipidemia after PI therapy. Several studies specifically implicated RTV, RTV/SQV, or NFV thera...

Directed screening of compounds selected from the Glaxo registry file for contractile activity on the isolated guinea pig gallbladder (GPGB) identified a series of 1,5-benzodiazepines with peripheral cholecystokinin (CCK) receptor agonist activity. Agonist efficacy within this series was modulated by variation of substituents on the N1-anilinoacetamide moiety. Remarkably, a single methyl group confers agonist activity, with an N-isopropyl substituent providing optimal efficacy. Hydrophilic substituents on the anilino nitrogen abolish agonist activity or produce antagonists of CCK. In contrast, hydrophilic electron-donating groups at the para-position of the anilino ring enhance or maintain in vitro and in vivo agonist activity. Despite decreased affinity for the human CCK-A receptor, relative to CCK-8, some of these compounds are equipotent to CCK as anorectic agents in rats following intraperitoneal administration.

Bile acids are recognized as metabolic modulators. The present study was aimed at evaluating the effects of a potent Asbt inhibitor (264W94), which blocks intestinal absorption of bile acids, on glucose homeostasis in Zucker Diabetic Fatty (ZDF) rats. Oral administration of 264W94 for two wk increased fecal bile acid concentrations and elevated non-fasting plasma total Glp-1. Treatment of 264W94 significantly decreased HbA1c and glucose, and prevented the drop of insulin levels typical of ZDF rats in a dose-dependent manner. An oral glucose tolerance test revealed up to two-fold increase in plasma total Glp-1 and three-fold increase in insulin in 264W94 treated ZDF rats at doses sufficient to achieve glycemic control. Tissue mRNA analysis indicated a decrease in farnesoid X receptor (Fxr) activation in small intestines and the liver but co-administration of a Fxr agonist (GW4064) did not attenuate 264W94 induced glucose lowering effects. In summary, our results demonstrate that inhibition of Asbt increases bile acids in the distal intestine, promotes Glp-1 release and may offer a new therapeutic strategy for type 2 diabetes mellitus.

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