Publications

Methionine-choline-deficient (MCD) diets that cause steatohepatitis in rodents are typically enriched in polyunsaturated fat. To determine whether the fat composition of the MCD formula influences the development of liver disease, we manufactured custom MCD formulas with fats ranging in PUFA content from 2% to 59% and tested them for their ability to induce steatohepatitis. All modified-fat MCD formulas caused identical degrees of hepatic steatosis and resulted in a similar distribution of fat within individual hepatic lipid compartments. The fatty acid composition of hepatic lipids, however, reflected the fat composition of the diet. Mice fed a PUFA-rich MCD formula showed extensive hepatic lipid peroxidation, induction of proinflammatory genes, and histologic inflammation. When PUFAs were substituted with more saturated fats, lipid peroxidation, proinflammatory gene induction, and hepatic inflammation all declined significantly. Despite the close relationship between PUFAs and hepatic inflammation in mice fed MCD formulas, dietary fat had no impact on MCD-mediated damage to hepatocytes. Indeed, histologic apoptosis and serum alanine aminotransferase levels were comparable in all MCD-fed mice regardless of dietary fat content. Together, these results indicate that dietary PUFAs promote hepatic inflammation but not hepatotoxicity in the MCD model of liver disease. These findings emphasize that individual dietary nutrients can make specific contributions to steatohepatitis.

Phospholipid scramblase 1 (PLSCR1) is a member of PLSCR gene family that has been implicated in multiple cellular processes including movement of phospholipids, gene regulation, immuno-activation, and cell proliferation/apoptosis. In the present study, we identified PLSCR1 as a positive intracellular acute phase protein that is upregulated by LPS in liver, heart, and adipose tissue, but not skeletal muscle. LPS administration resulted in a marked increase in PLSCR1 mRNA and protein levels in the liver. This stimulation occurred rapidly (within 2 h), and was very sensitive to LPS (half-maximal response at 0.1 microg/mouse). Moreover, two other APR-inducers, zymosan and turpentine, also produced significant increases in PLSCR1 mRNA and protein levels, indicating that PLSCR1 was stimulated in a number of models of the APR. To determine signaling pathways by which LPS stimulated PLSCR1, we examined the effect of proinflammatory cytokines in vitro and in vivo. TNFalpha, IL-1beta, and IL-6 all stimulated PLSCR1 in cultured Hep B3 hepatocytes, whereas only TNFalpha stimulated PLSCR1 in cultured 3T3-L1 adipocytes, suggesting cell type-specific effects of cytokines. Furthermore, the LPS-stimulated increase in liver PLSCR1 mRNA was greatly attenuated by 80% in TNFalpha and IL-1beta receptor null mice as compared to wild-type controls. In contrast, PLSCR1 levels in adipose tissue were induced to a similar extent in TNFalpha and IL-1beta receptor null mice and controls. These results indicate that maximal stimulation of PLSCR1 by LPS in liver required TNFalpha and/or IL-1beta, whereas the stimulation of PLSCR1 in adipose tissue is not dependent on TNFalpha and/or IL-1beta. These data provide evidence that PLSCR1 is a positive intracellular acute phase protein with a tissue-specific mechanism for up-regulation.

CONTEXT

Combination therapy is now widely advocated as first-line treatment for uncomplicated malaria in Africa. However, it is not clear which treatment regimens are optimal or how to best assess comparative efficacies in highly endemic areas.

OBJECTIVE

To compare the efficacy and safety of 3 leading combination therapies for the treatment of uncomplicated malaria.

DESIGN, SETTING, AND PARTICIPANTS

Single-blind randomized clinical trial, conducted between November 2004 and June 2006, of treatment for all episodes of uncomplicated malaria in children in an urban community in Kampala, Uganda. A total of 601 healthy children (aged 1-10 years) were randomly selected and were followed up for 13 to 19 months, receiving all medical care at the study clinic.

INTERVENTIONS

Study participants were randomized to receive 1 of 3 combination therapies (amodiaquine plus sulfadoxine-pyrimethamine, amodiaquine plus artesunate, or artemether-lumefantrine) when diagnosed with their first episode of uncomplicated malaria. The same assigned treatment was given for all subsequent episodes.

MAIN OUTCOME MEASURE

28-Day risk of parasitological failure (unadjusted and adjusted by genotyping to distinguish recrudescence from new infection) for each episode of uncomplicated malaria treated with study drugs.

RESULTS

Of enrolled children, 329 of 601 were diagnosed with at least 1 episode of uncomplicated malaria, and 687 episodes of Plasmodium falciparum malaria were treated with study drugs. The 28-day risk of treatment failure (unadjusted by genotyping) for individual episodes of malaria were 26.1% (95% CI, 21.1%-32.1%) for amodiaquine plus sulfadoxine-pyrimethamine, 17.4% (95% CI, 13.1%-23.1%) for amodiaquine plus artesunate, and 6.7% (95% CI, 3.9%-11.2%) for artemether-lumefantrine (P<.05 for all pairwise comparisons). When only recrudescent treatment failures were considered, the risks of failure were 14.1% (95% CI, 10.3%-19.2%), 4.6% (95% CI, 2.5%-8.3%), and 1.0% (95% CI, 0.3%-4.0%) for the same order of study drugs, respectively (P< or =.008 for all pairwise comparisons, except amodiaquine plus artesunate vs artemether-lumefantrine, P = .05). There were no deaths or cases of severe malaria. Significant reductions in anemia (9.3% [95% CI, 7.0%-12.0%] at enrollment vs 0.6% [95% CI, 0.1%-2.2%] during the last 2 months of follow-up; P<.001) and asymptomatic parasitemia (18.6% [95% CI, 15.5%-22.1%] at enrollment vs 2.3% [95% CI, 1.5%-3.5%] during the last 2 months of follow-up; P<.001) were observed according to routine testing.

CONCLUSIONS

Artemether-lumefantrine was the most efficacious treatment for uncomplicated malaria in the study population. With all study regimens, the provision of prompt and reasonably effective facility-based treatment was associated with good outcomes in long-term health measures.

TRIAL REGISTRATION

isrctn.org Identifier: ISRCTN37517549.