Response of porcine hepatocytes in primary culture to plasma from severe viral hepatitis patients

AIM： To observe the effects of plasma from patients with severe viral hepatitis （SVHP） on the growth and metabolism of porcine hepatocytes and the clinical efficiency of bioartificial liver device.METHODS： Hepatocytes were isolated from male porcines by collagenase perfusion. The synthesis of DNA and total protein, leakages of AST and LDH, changes in glutathione （GSH）, catalase and morphology of porcine hepatocytes exposed to SVHP were investigated to indicate the effect of plasma from patients with severe hepatitis on the growth, injury, detoxification, and morphology of porcine hepatocytes.RESULTS： The synthesis of DNA and protein was inhibited in the medium containing 100% SVHP compared to the controls. The leakages of LDH and AST increased in porcine hepatocytes following exposure to 100% SVHP for 5 h. The difference between 100% SVHP and 10% newborn calf serum （NCS） was significant in t-test （LDH： t = 24.552, P = 0.001; AST： t = 4.169, P = 0.014）. After exposure to SVHP for 24 h, alterations in GSH status were significant （F = 2.746, P〈0.05） between porcine hepatocytes in 100% SVHP and 10% NCS, but no alteration occurred in the culture medium after 48 h （F = 4.378, ,P〈0.05）. A similar profile was observed in catalase activity. Many round vacuoles were observed in porcine hepatocytes cultured in SVHR The membranes of these cells became indistinct and almost all the cells died on d 5.CONCLUSION： Plasma from patients with severe hepatitis inhibits the growth, injures membrane, disturbs GSH homeostasis and induces morphological changes of porcine hepatocytes, It is suggested that SVHP should be pretreated to reduce the toxin load and improve the performance of porcine hepatocytes in extracorporeal liver-support devices.

Micro RNAs in the development of non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease or nonalcoholic fatty liver disease(NAFLD) refers to a group of disorders that arise from the accrual of fat in hepatocytes. Although various factors have been associated with the development of NAFLD, including genetic predisposition and environmental exposures, little is known aboutthe underlying pathogenesis of the disease. Research efforts are ongoing to identify biological targets and signaling pathways that mediate NAFLD. Emerging evidence has implicated a role for micro RNAs(mi RNAs), short single-stranded molecules that regulate gene expression either transcriptionally, through targeting of promoter regions, or post-transcriptionally, by blocking translation or promoting cleavage of specific target m RNAs. Several mi RNAs have been associated with NAFLD, although our understanding of the biology underlying their role is still emerging. The goal of this review is to present an overview of the current state of knowledge of mi RNAs involved in the development of NAFLD across a range of in vitro and in vivo models, including mi RNAs that contribute to pathological mechanisms related to fatty liver in humans. Much less is known about the specific targets of mi RNAs in cells, nor the molecular mechanisms involved in the development and progression NAFLD and related outcomes. More recently, the identification and validation of mi RNA signatures in serum may facilitate the development of improved methods for diagnosis and clinical monitoring of disease progression.

Disruption of colonic barrier function and induction of mediator release by strains of Campylobacter jejuni that invade epithelial cells

AIM: To study the mechanisms by which Campylobacter jejuni (C. jejuni) causes inflammation and diarrhea. In particular, direct interactions with intestinal epithelial cells and effects on barrier function are poorly under- stood. METHODS: To model the initial pathogenic effects of C. jejuni on intestinal epithelium, polarized human colonic HCA-7 monolayers were grown on permeabilized filters and infected apically with clinical isolates of C. jejuni. Integrity of the monolayer was monitored by changes in monolayer resistance, release of lactate dehydrogenase, mannitol fluxes and electron microscopy. Invasion of HCA-7 cells was assessed by a modified gentamicin protection assay, translocation by counting colony forming units in the basal chamber, stimulation of mediator release by immunoassays and secretory responses in monolayers stimulated by bradykinin in an Ussing chamber. RESULTS: All strains translocated across monolayers but only a minority invaded HCA-7 cells. Strains that invaded HCA-7 cells destroyed monolayer resistance over 6 h, accompanied by increased release of lactate dehydrogenase, a four-fold increase in permeability to [3H] mannitol, and ultrastructural disruption of tight junctions, with rounding and lifting of cells off the filter membrane. Synthesis of interleukin (IL)-8 and prostaglandin E2 was increased with strains that invaded the monolayer but not with those that did not. CONCLUSION: These data demonstrate two distinct effects of C. jejuni on colonic epithelial cells and provide an informative model for further investigation of initial host cell responses to C. jejuni.