In vitro expansion of cirrhosis derived liver epithelial cells with defined small molecules.

BACKGROUND & AIMS: Mature hepatocytes have limited expansion capability in culture and rapidly loose key functions. Recently however, tissue culture conditions have been developed that permit rodent hepatocytes to proliferate and transform into progenitor-like cells with ductal characteristics in vitro. Analogous cells expressing both hepatic and duct markers can be found in human cirrhotic liver in vivo and may represent an expandable population. METHODS: An in vitro culture system to expand epithelial cells from human end stage liver disease organs was developed by inhibiting the canonical TGF-ß, Hedgehog and BMP pathways. RESULTS: Human cirrhotic liver epithelial cells became highly proliferative in vitro. Both gene expression and DNA methylation site analyses revealed that cirrhosis derived epithelial liver cells were intermediate between normal hepatocytes and cholangiocytes. Mouse hepatocytes could be expanded under the same conditions and retained the ability to re-differentiate into hepatocytes upon transplantation. In contrast, human cirrhotic liver derived cells had only low re-differentiation capacity. CONCLUSIONS: Epithelial cells of intermediate ductal-hepatocytic phenotype can be isolated from human cirrhotic livers and expanded in vitro. Unlike their murine counterparts they have limited liver repopulation potential.

Use of the nonwire central line hub to reduce blood culture contamination.

BACKGROUND: The sterile conditions used when inserting a central venous catheter (CVC) might be thought to decrease the contamination rate of blood cultures taken at CVC insertion; however, a previous retrospective study showed the opposite, that such blood cultures are contaminated more frequently than peripheral venipuncture blood cultures. The current study explored whether use of the CVC nonwire hub as a source of blood cultures decreased contamination while maintaining detection of true pathogens. METHODS: A prospective, observational study was performed from June 2010 to May 2011 in the general ICU of an academic, tertiary referral center. The proportions of blood cultures taken from wire and nonwire CVC hubs growing contaminants and true pathogens were compared. Risk factors for blood culture contamination were identified, and multivariate analysis was used to identify independent predictors of blood culture contamination. RESULTS: Among 313 blood cultures taken from 227 CVCs in 139 patients, 27 of 141 wire hub (19%) vs nine of 172 nonwire hub (5%) cultures were contaminated (P < .001). Only hub of blood culture origin was associated with contamination on multivariate analysis (OR, 4.3; 95% CI, 1.9-9.5; P < .001). True pathogens grew in 19 of 141 wire hub (13%) vs 27 of 172 nonwire hub (16%) cultures (P = .581). CONCLUSIONS: A higher proportion of blood cultures taken from the CVC lumen exposed to the guidewire were contaminated when compared with nonwire hub cultures; detection of true pathogens was equivalent. To limit detrimental sequelae of blood culture contamination, blood cultures obtained at CVC insertion should be taken from the nonwire hub.