Antithrombin prevents reperfusion-induced hepatic apoptosis by enhancing insulin-like growth factor-I production in mice:

Early prediction of postoperative liver dysfunction and clinical outcome using antithrombin III-activity

BACKGROUND AND AIMS

Antithrombin III (ATIII) has been reported to be associated with liver pathologies and was shown to predict outcome in patients undergoing liver resection for hepatocellular carcinoma. We now aimed to assess whether perioperative ATIII-activity could predict postoperative outcome in patients without underlying liver disease, as well as in a routine clinical setting of patients undergoing hepatic resection.

METHODS

ATIII-activity was evaluated preoperatively and on the first (POD1) and fifth day after liver resection in a retrospective evaluation cohort of 228 colorectal cancer patients with liver metastasis (mCRC). We further aimed to prospectively validate our results in a set of 177 consecutive patients undergoing hepatic resection.

RESULTS

Patients developing postoperative liver dysfunction (LD) had a more pronounced postoperative decrease in ATIII-activity (P<0.001). ATIII-activity on POD1 significantly predicted postoperative LD (P<0.001, AUC = 84.4%) and remained independent upon multivariable analysis. A cut-off value of 61.5% ATIII-activity was determined using ROC analysis. This cut-off was vital to identify high-risk patients for postoperative LD, morbidity, severe morbidity and mortality (P<0.001, respectively) with a highly accurate negative predictive value of 97%, which could be confirmed for LD (P<0.001) and mortality (P = 0.014) in our independent validation cohort. Further, mCRC patients below our cut-off suffered from a significantly decreased overall survival (OS) at 1 and 3 years after surgery (P = 0.011, P = 0.025).

CONCLUSIONS

The routine laboratory parameter ATIII-activity on POD1 independently predicted postoperative LD and was associated with clinical outcome. Patients with a postoperative ATIII-activity <61.5% might benefit from close monitoring and timely initiation of supportive therapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01700231.

Aggravation of post-ischemic liver injury by overexpression of insulin-like growth factor binding protein 3

Insulin-like growth factor-1 (IGF-1) is known to inhibit reperfusion-induced apoptosis. IGF-binding protein-3 (IGFBP-3) is the major circulating carrier protein for IGF-1 and induces apoptosis. In this study, we determined if IGFBP-3 was important in the hepatic response to I/R. To deliver IGFBP-3, we used an adenovirus containing IGFBP-3 cDNA (AdIGFBP-3) or an IGFBP-3 mutant devoid of IGF binding affinity but retaining IGFBP-3 receptor binding ability (AdIGFBP-3(GGG)). Mice subjected to I/R injury showed typical patterns of hepatocellular damage. Protein levels of IGFBP-3 were increased after reperfusion and showed a positive correlation with the extent of liver injury. Prior injection with AdIGFBP-3 aggravated liver injury: serum aminotransferases, prothrombin time, proinflammatory cytokines, hepatocellular necrosis and apoptosis, and neutrophil infiltration were markedly increased compared to control mice. A decrease in antioxidant potential and an upregulation of NADPH oxidase might have caused these aggravating effects of IGFBP-3. Experiments using HepG2 cells and N-acetylcysteine-pretreated mice showed a discernible effect of IGFBP-3 on reactive oxygen species generation. Lastly, AdIGFBP-3 abolished the beneficial effects of ischemic preconditioning and hypothermia. Mice treated with AdIGFBP-3(GGG) exhibited effects similar to those of AdIGFBP-3, suggesting a ligand-independent effect of IGFBP-3. Our results suggest IGFBP-3 as an aggravating factor during hepatic I/R injury.

Stimulation of sensory neurons improves cognitive function by promoting the hippocampal production of insulin-like growth factor-I in mice

Calcitonin gene-related peptide (CGRP) increases the production of insulin-like growth factor-I (IGF-I) in the mouse brain. IGF-I exerts beneficial effects on the cognitive function by increasing synaptic transmission and by inducing angiogenesis and neurogenesis in the hippocampus. In the current study, we examined whether stimulation of sensory neurons by capsaicin improved the cognitive function by increasing the production of IGF-I in the hippocampus using wild-type (WT) and CGRP-knockout (CGRP-/-) mice. Significant increases of the hippocampal tissue levels of CGRP, IGF-I, and IGF-I messenger RNA (mRNA) were observed after capsaicin administration in WT mice (P < 0.01) but not in CGRP-/- mice. Increase in the expression of c-fos was also observed in the spinal dorsal horn, the parabrachial nuclei, and the hippocampus after capsaicin administration in WT mice but not in CGRP-/- mice. Significant enhancement of angiogenesis and neurogenesis was observed in the dentate gyrus of the hippocampus after capsaicin administration in WT mice (P < 0.01) but not in CGRP-/- mice. Although capsaicin administration improved spatial learning in WT mice, no such effect was observed in CGRP-/- mice. Capsaicin-induced improvement of the spatial learning was reversed by administration of an anti-IGF-I antibody and by that of a CGRP receptor antagonist CGRP (8-37) in WT mice. The administration of IGF-I improved the spatial learning in both WT and CGRP-/- mice. These observations strongly suggest that the stimulation of sensory neurons by capsaicin might increase IGF-I production via increasing the hippocampal tissue CGRP levels, and it may thereby promote angiogenesis and neurogenesis to produce improvement of the cognitive function in mice.