Streaming liver. VIII: Cell production rates following partial hepatectomy

Liver regeneration: mechanisms, mysteries and more

BACKGROUND

Liver regeneration remains a fascinating topic, still partly clouded to many as to the exact cellular and molecular mechanisms that bring about this phenomenon. It is an area, therefore, of active research today. This review looks at the recent published reports that have led to a greater understanding of this process.

METHODS

A database search was carried out on Medline search using the terms liver regeneration with no linguistic limitations from 1966 to 2006.

RESULTS

There are two randomized controlled trials on the topic and most data and information have come from experimental studies in animals.

CONCLUSION

Liver regeneration is a complex, tightly controlled process involving many inflammatory cells growth factors and hormones. More information about it is awaited in studies on humans.

Evaluation of Liver Support Systems for Preclinical Testing by Animal Trials

In the present review, various animal models of acute liver failure are reviewed with respect to their suitability for evaluating liver support systems (LSS) according to envisaged modes of therapy. In order to increase the value of the preclinical testing of LSS, it would be advantageous to include more than one animal model in the evaluation program. It is possible to identify appropriate sets of models, which make a suitable test system for particular clinical applications. A standardization of evaluation methods between testing groups would also be beneficial to the field of liver support.

Change of zonal bile acid processing after partial hepatectomy in the rat

The aim of this study was to analyze whether partial hepatectomy alters functional liver heterogeneity with respect to bile acid processing. One, 5 and 21 days after liver resection (approximately 80% of liver mass) in male Sprague-Dawley rats (300-400 g), isolated livers were perfused in either the antegrade or the retrograde direction, respectively, with 32 nmol cholate/min per g liver. Uptake, metabolism and biliary secretion kinetics were determined by bolus injection of 14C-cholate. Uptake and biliary recovery (within 30 min) of cholate were > 90% in all groups. One day postresection, liver mass had already doubled and it regenerated to over 80% 5 days after resection. Serum bile acid concentration increased rapidly, peaking 6 h after resection (176.7 +/- 28.5 mumol/l) (mean +/- SEM). Twenty-one days after resection it fell to control values (23.2 +/- 3.8 mumol/l). T25 (T50), the time (min) necessary to excrete 25% (50) of the bile acid load into bile, was strikingly different between periportal and pericentral cells of controls (1.8 vs 5.7 and 3.4 vs 8.1). Five days after resection this difference became smaller (1.4 vs 2.9 and 2.8 vs 5.5) due to accelerated biliary cholate secretion in pericentral cells. Pericentral cells of controls metabolized cholate more extensively to taurocholate (approximately 83%) and glycocholate (approximately 13%) than periportal cells of controls (65%, 10%), leading to a 5-fold higher proportion of unmetabolized cholate in periportal than pericentral cells (25% vs 5%). Five days after resection the percentage of taurocholate decreased significantly at the expense of an increased formation of glycocholate.(ABSTRACT TRUNCATED AT 250 WORDS)