Megamitochondria with crystalline inclusions (MMC) have been previously described in nonalcoholic fatty liver; however, their distribution within hepatic zones is unknown. We sought to determine this distribution from the core liver biopsy specimens of 31 patients: 8 males and 23 females, age range 21 to 72 years. Twenty-nine showed evidence of nonalcoholic steatohepatitis (NASH) on biopsy with steatosis, inflammation, varying degree of fibrosis, ballooned hepatocytes, and Mallory hyaline, and two patients had cryptogenic cirrhosis thought to represent "burned out" NASH. Identified by transmission electron microscopy, the abundance of MMC was compared between low-stage (fibrosis stages 1 and 2) and high-stage (fibrosis stages 3 and 4) groups and between zones with or without difference in fibrosis stage. Regardless of stage, the MMC were distributed equally in all zones and were abundant similarly in low-and high-stage groups. This abundance did not correlate with the degree of oxidative stress (4-hydroxynonenal staining) or with the abundance of ballooned hepatocytes. Consistent with age as a risk factor for more severe disease, the median age for the low-stage group was significantly lower than that of the high-stage group (P ‫؍‬ .003). In conclusion, in NASH, the MMC seem to be distributed randomly among zones and without variation in abundance, regardless of the fibrosis stage. The exact function of these structures remains to be defined. In this study, their presence did not seem to correlate with the light microscopic injury pattern represented by ballooned hepatocytes or degree of oxidative stress defined by immunostaining for 4-hydroxynonenal. (HEPATOLOGY

Hypercholesterolemia is a common problem among transplant recipients. Despite package-insert warnings about the potential side effects of the use of statins in patients with chronic liver disease, they are often prescribed for liver transplant recipients. Unlike statins, ezetimibe acts through inhibition of enterohepatic recirculation of lipids. We report the effectiveness and safety of ezetimibe among liver transplant recipients because this has been evaluated previously only in kidney and heart transplant patients. A consecutive cohort of 25 liver graft recipients with serum low-density lipoprotein (LDL) levels Ͼ 100 mg/dL (2.5 mmol/L) after a mean (Ϯstandard deviation) of 55 Ϯ 21 months following liver transplantation received ezetimibe (10 mg orally every day) for at least 6 months. Serum lipid profiles, liver and renal function tests, and dosages and blood levels of the immunosuppression drugs at baseline, 3 months, and 6 months were prospectively collected. The overall mean age was 58 Ϯ 12 years, and 56% were males. Statin therapy and fibrates were already being used in 32% and 20% of recipients for elevated LDL and/or triglycerides, respectively. The immunosuppression regimen included cyclosporine in 48% of subjects, tacrolimus in 32%, sirolimus in 48%, and mycophenolate mofetil in 44%; only 12% were on oral prednisone with a maximum daily dose of 5 mg. After ezetimibe was started, an 18% reduction in LDL values was observed [at baseline, 147 Ϯ 35 mg/dL (3.8 Ϯ 0.9 mmol/L), and at 6 months, 120 Ϯ 31 mg/dL (3.1 Ϯ 0.8 mmol/L); P ϭ 0.010]. After 6 months, an additional 32% achieved the target LDL level of Ͻ100 mg/dL. None of the remaining variables, including immunosuppression drug levels, varied significantly during ezetimibe therapy. None of the subjects required adjustments in their pharmacological dosages. One discontinued ezetimibe 3 months later because of cost, 2 subjects had minimal nausea, 1 subject had myalgias without a rise in creatine phosphokinase, and 1 subject had a transient elevation (3-5 times) in liver enzymes from baseline with increases in the total and indirect bilirubin levels. In conclusion, among liver transplant recipients, hypercholesterolemia can be effectively treated with ezetimibe with few side effects and no interaction with immunosuppressive regimens. Liver Transpl 15:504-508, 2009. © 2009 AASLD. Received August 5, 2008 accepted November 16, 2008. After orthotopic liver transplantation (OLT) in the adult population, between 16% and 43% of recipients will develop hypercholesterolemia, and 40% will develop hypertriglyceridemia, with the majority suffering from mixed hyperlipidemia.

The structural gene encoding liver-specific tyrosine aminotransferase (TAT; EC 2.6.1.5) was assigned to mouse chromosome 8 by screening a series of hybrid cell lines for retention of murine Tat-1 gene sequences by genomic Southern blotting. This assignment demonstrated that the Tat-1 structural gene was not syntenic with Tse-1, a chromosome 11-linked locus that negatively regulates TAT expression in trans (A. M. Killary and R. E. K. Fournier, Cell 38:523-534, 1984). We also showed that the fibroblast Tat-1 gene was systematically activated in hepatoma X fibroblast hybrids retaining fibroblast chromosomes 8 in the absence of chromosome 11 but was extinguished in cells retaining both fibroblast chromosomes. Thus, the TAT structural genes of both parental cell types were coordinately regulated in the intertypic hybrids, and the TAT phenotype of the cells was determined by the presence or absence of fibroblast Tse-1.

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