Metabolism for cyclosporin A during liver regeneration after partial hepatectomy in rats

Pregnane X receptor activation induces liver enlargement and regeneration and simultaneously promotes the metabolic activity of CYP3A1/2 and CYP2C6/11 in rats

Human pregnane X receptor (PXR) is critical for regulating the expression of key drug-metabolizing enzymes such as CYP3A and CYP2C. Our recent study revealed that treatment with rodent-specific PXR agonist pregnenolone-16α-carbonitrile (PCN) significantly induced hepatomegaly and promoted liver regeneration after two-thirds partial hepatectomy (PHx) in mice. However, it remains unclear whether PXR activation induces hepatomegaly and liver regeneration and simultaneously promotes metabolic function of the liver. Here, we investigated the metabolism activity of CYP1A2, CYP3A1/2 and CYP2C6/11 during PXR activation-induced liver enlargement and regeneration in rats after cocktail dosing of CYP probe drugs. For PCN-induced hepatomegaly, a notable increase in the metabolic activity of CYP3A1/2 and CYP2C6/11, as evidenced by the plasma exposure of probe substrates and the AUC ratios of the characteristic metabolites to its corresponding probe substrates. The metabolic activity of CYP1A2, CYP3A1/2 and CYP2C6/11 decreased significantly after PHx. However, PCN treatment obviously enhanced the metabolic activity of CYP2C6/11 and CYP3A1/2 in PHx rats. Furthermore, the protein expression levels of CYP3A1/2 and CYP2C6/11 in liver were up-regulated. Taken together, this study demonstrates that PXR activation not only induces hepatomegaly and liver regeneration in rats, but also promotes the protein expression and metabolic activity of the PXR downstream metabolizing enzymes such as CYP3A1/2 and CYP2C6/11 in the body.

Albumin is a secret factor involved in multidirectional interactions among the serotoninergic, immune and endocrine systems that supervises the mechanism of CYP1A and CYP3A regulation in the liver

This review focuses on albumin, which is involved in multidirectional interactions among the immune, endocrine and serotoninergic systems and supervises the regulation of cytochrome P450 (CYP) isoforms under conditions of both normal liver function and liver insufficiency. Special attention is paid to albumin, thyroid hormones, testosterone and tryptophan hydroxylase in these interactions as well as their potential roles in liver regeneration. The association of these factors with inflammation and the modification of the mechanism of hepatic drug-metabolizing CYP isoform regulation are also presented because changes in the expression of CYP isoforms in the liver may result in subsequent changes to a marker substance used for testing CYP activity, thus providing a simple way to control the liver regeneration process or the dangerous stimulation of hepatocarcinogenesis.

Modified ALPPS Procedures Avoiding Division of Portal Pedicles

OBJECTIVE

We describe a modified procedure associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) including portal pedicle preservation during parenchymal division, thus avoiding necrosis.

BACKGROUND

Although ALPPS recently has been advocated for treating advanced liver tumors, sepsis originating from the ischemic area produced by parenchymal division increases mortality, accounting for one-third of postoperative deaths.

METHODS

Our procedure differs from the original ALPPS technique by sparing portal pedicles at the transection plane, thus maintaining blood supply. The preserved pedicles are segment 4 (S4) in right lobectomy plus right portal vein ligation (PVL), S1 in extended right hepatectomy (extended to S1) plus right PVL, lateral portal pedicles of the right paramedian sector (RPS) in extended right lateral sectoriectomy plus lateral PVL, and both portal pedicles of the lateral RPS and S1 in extended right lateral sectoriectomy with S1 resection plus lateral PVL.

RESULTS

These procedures were performed in 5 patients. Morbidity rates at first- and second-stage operations were 0% and 80%, without mortality. Mean hypertrophy of the future liver remnant was 1.638 ± 0.384 a week after the first-stage procedure.

CONCLUSIONS

Our technique stimulates rapid hypertrophy and may improve safety in ALPPS.

[Effects of berberine on the recovery of rat liver xenobiotic-metabolizing enzymes after partial hepatectomy]

We have studied the effect of berberine on the recovery processes of liver xenobiotic-metabolizing function during its compensatory growth after 70% partial hepatectomy. It was found the hepatic ability to metabolize foreign substances are not restored up to day 8. Administration of berberine (10 mg/kg intraperitoneally) for 6 days led to normalization of both cytochrome P450-dependent and flavin-containing monooxygenases. It is suggested that in the biotransformation of berberine involved not only cytochrome P450, but also flavin-containing monooxygenases.