Adam P. Levene

The epidemiology, pathogenesis and histopathology of fatty liver disease.

Levene A P & Goldin R D 
(2012) Histopathology 61, 141–152

Impact of pan-caspase inhibition in animal models of established steatosis and non-alcoholic steatohepatitis

BACKGROUND & AIMS Non-alcoholic fatty liver disease is a progressive condition comprising steatosis, steatohepatitis, and cirrhosis. Caspase activation mediates apoptosis and the inflammatory response. Studies demonstrate increased apoptotic activity in NASH although its pathophysiological importance is uncertain. We sought to determine the effects of irreversible pan-caspase inhibition in murine models of established steatosis (high fat diet, HFD) and steatohepatitis (methionine-choline deficient diet, MCD). METHODS In one study arm, male C3H/HeN mice were fed HFD; in the other, Db/Db mice were fed MCD. Once disease was established, animals were randomised to receive caspase inhibitor (VX-166), TPGS/PEG vehicle or no additional therapy until the end of the study. Biochemical and histological indices were examined to determine NASH activity and tissue oxidative stress. Apoptotic activity and cell turnover were assessed immunohistochemically by staining for caspase-cleaved CK-18 and PCNA. RESULTS MCD and HFD significantly increased apoptosis, which was reduced by VX-166 treatment. VX-166 did not reduce steatosis but reduced histological inflammation, serum ALT levels, and oxidative stress, particularly in the MCD model. TPGS/PEG vehicle also exhibited some anti-inflammatory activity. CONCLUSIONS In both models, VX-166 inhibited apoptosis and reduced histological inflammatory infiltrate although there was a more modest impact on other indices of liver injury. In addition, TPGS/PEG vehicle also exhibited some anti-inflammatory activity, likely through the antioxidant effects of vitamin E and changes in gut flora/mucosal interactions. These data suggest that caspase inhibition may represent a valid therapeutic approach; however, further studies to assess the long-term value of more selective caspase inhibition are merited.

LKB1 is required for hepatic bile acid transport and canalicular membrane integrity in mice

LKB1 is a ‘master’ protein kinase implicated in the regulation of metabolism, cell proliferation, cell polarity and tumorigenesis. However, the long-term role of LKB1 in hepatic function is unknown. In the present study, it is shown that hepatic LKB1 plays a key role in liver cellular architecture and metabolism. We report that liver-specific deletion of LKB1 in mice leads to defective canaliculi and bile duct formation, causing impaired bile acid clearance and subsequent accumulation of bile acids in serum and liver. Concomitant with this, it was found that the majority of BSEP (bile salt export pump) was retained in intracellular pools rather than localized to the canalicular membrane in hepatocytes from LLKB1KO (liver-specific Lkb1-knockout) mice. Together, these changes resulted in toxic accumulation of bile salts, reduced liver function and failure to thrive. Additionally, circulating LDL (low-density lipoprotein)-cholesterol and non-esterified cholesterol levels were increased in LLKB1KO mice with an associated alteration in red blood cell morphology and development of hyperbilirubinaemia. These results indicate that LKB1 plays a critical role in bile acid homoeostasis and that lack of LKB1 in the liver results in cholestasis. These findings indicate a novel key role for LKB1 in the development of hepatic morphology and membrane targeting of canalicular proteins.

Quantifying hepatic steatosis – more than meets the eye

Levene A P, Kudo H, Armstrong M J, Thursz M R, Gedroyc W M, Anstee Q M & Goldin R D 
(2012) Histopathology 60, 971–981

Multi-Excitation Fluorescence Spectroscopy for Analysis of Non-Alcoholic Fatty Liver Disease

The increasing incidence of non‐alcoholic fatty liver diseases (NAFLD) and the consequent progression to cirrhosis is expected to become a major cause of liver transplantation. This will exacerbate the organ donor shortage and mean that ‘marginal’ fatty liver grafts are more frequently used. Autofluorescence spectroscopy is a fast, objective, and non‐destructive method to detect change in the endogenous fluorophores distribution and could prove to be a valuable tool for NAFLD diagnosis and transplant graft assessment.

Physiological hepatic nuclear vacuolation--how long does it persist?

Levene A P & Goldin R D
(2010) Histopathology56, 426–429 Physiological hepatic nuclear vacuolation—how long does it persist?

Is oil red‐O staining and digital image analysis the gold standard for quantifying steatosis in the liver?

We read with great interest the article by Petta et al. The compound 25-hydroxyvitamin D3 (25[OH]D3) was reported as an independent predictor of cardiovascular disease (by a decreased expression of profibrotic markers, and an increased expression of antifibrotic markers) despite the fact that its real pathological pathway is still not clear. Incubation of the multipotent mesenchymal cell with 25(OH)D3 also resulted in antiproliferative and antiapoptotic processes. Therefore, the lower levels of 25(OH)D3 in liver with greater fibrosis is understandable. Lower cholesterol and lower 25(OH)D3 levels, along with greater steatosis, were found to be risk factors affecting sustained virological response (SVR) as seen in recent studies. The stage of fibrosis was found to be a risk factor for SVR not only in hepatitis C virus (HCV) alone, but also in patients coinfected with human immunodeficiency virus and HCV, in contrast to the results of the current article. Moreover, age, sex, and body mass index were also described as predictors for SVR in patients infected with HCV, in contrast to the current study. These challenging results could be related in the methodologic differences between the present study and recent studies, or mistakes could have happened during the sampling and/or analyzing periods. For example, SVR was reached in the half the male patients, whereas it was reached in just one-third of the females, results which are also different from the recent data. The patients in the study may also be infected with an unknown subgroup of HCV, which could explain these patients’ characteristics.

Visual loss secondary to eosinophilic mucin rhinosinusitis in a woman: a case report

IntroductionEosinophilic mucin rhinosinusitis is an inflammatory pathological condition of the nose and paranasal sinuses. It is rare, occurs in immunocompetent patients and is characterised by peripheral eosinophilia and extensive bilateral sinus disease. To the best of our knowledge, visual loss with this condition has not been previously reported.Case presentationWe present the case of a 26-year-old Asian woman with a background history of chronic sinusitis who presented with acute left-sided visual loss. Imaging showed significant opacification in the frontal, ethmoidal and sphenoidal sinuses as well as evidence of a unilateral optic neuritis. Histological analysis of sinus mucin revealed dense eosinophilic infiltrate and, despite medical and surgical intervention, vision was not restored in her left eye.ConclusionWe introduce visual loss as a complication of eosinophilic mucin rhinosinusitis. This adds further evidence to previous reports in the literature that optic neuropathy in sinusitis can occur secondary to non-compressive mechanisms. We also describe a rare finding: the vision in this patient did not improve following steroid therapy, antifungal therapy or surgical intervention. There are very few such cases described in the literature. We conclude that chronic sinusitis is an indolent inflammatory process which can cause visual loss and we reiterate the importance of recognizing and considering sinusitis as a cause of visual loss in patients in order that prompt medical and surgical treatment of the underlying disease can be initiated.