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Identification of patients at risk of a complicated course after liver resection is crucial for adapting post-operative care. In the present study, we investigated the diagnostic value of the plasma levels of various cytokines obtained immediately after surgery. IL-6, IL-10, IL-8, monokine induced by interferon-γ (MIG), monocyte chemotactic protein-1 (MCP-1) and interferon-inducible protein-10 (IP-10) concentrations were measured in 26 patients after liver resection using a cytometric bead assay and were correlated with liver function, resectate weight, surgery duration, ischemia/reperfusion, hospitalization time and occurrence of complications. Patients with post-surgical complications showed distinctive patterns of IL-6 and IL-8 as early as minutes to hours after surgery. In addition, although pre-operative bilirubin in most patients remained within the normal range, a cut-off of 1 mg/dl separated the patients into groups with different profiles of IL-6, IL-8, and MCP-1 secretion and different likelihoods of experiencing post-operative complications (bilirubin levels ≥1.0 vs. <1.0 mg/dl; IL-6 (4 h): 701 vs. 265; IL-8 (6 h): 262 vs. 97 pg/ml; p<0.05 for both). Extended hospitalization, related to delayed recovery, was correlated with increased IL-8 and MCP-1 immediately after surgery. In conclusion, on the basis of these observations, we suggest that early measurement of post-operative levels of MCP-1, IL-6, and IL-8 can be used to identify individuals at risk of post-operative complications immediately after liver surgery.

Protective hepatocellular responses to a hypoxic challenge are crucial to preserve liver function. The knowledge of affected metabolic functions could help assess and enhance hepatic ischemic tolerance. Here we studied adaptive mechanisms in human hepatocytes after hypoxia and reoxygenation using a proteomic approach. Proteins from primary hepatocytes were extracted after 6 h of hypoxia and 24 h of reoxygenation. The proteome was analyzed by 2D-electrophoresis. Densitometry and mass spectrometry (MALDI-TOF-MS) were used for protein identification. Two hundred and sixty-two spots were differentially analyzed and 33 spots displayed significant differences between hypoxic and normoxic cells. Seventeen proteins were identified by mass spectrometry. After hypoxia and reoxygenation the UTP-glucose-1-phosphate uridyltransferase, phosphoglycerate kinase1, fructose-1,6-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, fructose-1,6-bisphosphatase, thiosulfat-sulfurtransferase, thioredoxin peroxidase, peroxiredoxin III, and annexin A2 proteins were down-regulated. An increased expression was found for carbamoyl phosphate synthetase I, heat shock 70 kDa protein5, phosphoenolpyruvate carboxy-kinase, catalase isoform2, peroxiredoxin II, glutathione S-transferase, hydroxyacid oxidase1, and F1-ATP synthase, alpha subunit1. Hepatocellular adaptation to hypoxia and reoxygenation involve glucose metabolism, peroxisomal functions, and oxidative stress protection. The identified proteins can serve as possible diagnostic targets to monitor hepatic hypoxic tolerance e.g. in the context of liver surgery and transplantation.

Isolated human hepatocytes are of great value in investigating cell transplantation, liver physiology, pathology, and drug metabolism. Though hepatocytes possess a tremendous proliferative capacity in vivo, their ability to grow in culture is severely limited. We postulated that repeated medium change, common to most in vitro systems, may prevent long-term maintenance of hepato-specific functions and growth capacity. To verify our hypotheses we compared the DNA synthesis and differentiation status of isolated human hepatocytes, cultured in medium which was renewed every day or was not changed for 3 weeks ('autocrine' setting). Daily medium change led to rapid hepatocellular de-differentiation without any signs of DNA replication. In contrast, the autocrine setting allowed hepatocytes to become highly differentiated, demonstrated by an elevated ASGPr expression level, and increased albumin and fibrinogen synthesis and release. Cytokeratin 18 filaments were stably expressed, whereas cytokeratin 19 remained undetectable. Hepatocytes growing in an autocrine fashion were activated in the presence of hepatocyte growth factor (HGF), evidenced by c-Met phosphorylation. However, HGF response was not achieved when the culture medium was renewed daily. Furthermore, the autocrine setting evoked a late but strong interleukin 6 release into the culture supernatant, reaching maximum values after a 10-day cultivation period, and intense BrdU incorporation after a further 5-day period. Our data suggest that preservation of the same medium creates environmental conditions which allow hepatocytes to control their differentiation status and DNA synthesis in an autocrine fashion. Further studies are necessary to identify the key mediators involved in autocrine communication and to design the optimal culture configuration for clinical application.