The effects of sorafenib on liver regeneration in a model of partial hepatectomy

Changes in Liver Volume Observed Following Sorafenib and Liver Radiation Therapy

PURPOSE

The purpose of this study was to quantify unexpected liver volume reductions in patients treated with sorafenib prior to and during liver radiation therapy (RT).

METHODS AND MATERIALS

Fifteen patients were treated in a phase 1 study of sorafenib for 1 week, followed by concurrent sorafenib-RT (in 6 fractions). Patients had either focal cancer (treated with stereotactic body RT [SBRT]) or diffuse disease (treated with whole-liver RT). Liver volumes were contoured and recorded at planning (day 0) from the exhale CT. After 1 week of sorafenib (day 8), RT image guidance at each fraction was performed using cone beam CT (CBCT). Planning liver contours were propagated and modified on the reconstructed exhale CBCT. This was repeated in 12 patients treated with SBRT alone without sorafenib. Three subsequent patients (2 sorafenib-RT and 1 non-sorafenib) were also assessed with multiphasic helical breath-hold CTs.

RESULTS

Liver volume reductions on CBCT were observed in the 15 sorafenib-RT patients (median decrease of 68 cc, P=.02) between day 0 and 8; greater in the focal (P=.025) versus diffuse (P=.52) cancer stratum. Seven patients (47%) had reductions larger than the 95% intraobserver contouring error. Liver reductions were also observed from multiphasic CTs in the 2 additional sorafenib-RT patients between days 0 and 8 (decreases of 232.5 cc and 331.7 cc, respectively) and not in the non-sorafenib patient (increase of 92 cc). There were no significant changes in liver volume between planning and first RT in 12 patients with focal cancer treated with SBRT alone (median increase, 4.8 cc, P=.86).

CONCLUSIONS

Liver volume reductions were observed after 7 days of sorafenib, prior to RT, most marked in patients with focal liver tumors, suggesting an effect of sorafenib on normal liver. Careful assessment of potential liver volume changes immediately prior to SBRT may be necessary in patients in sorafenib or other targeted therapies.

The effect of sorafenib on liver regeneration and angiogenesis after partial hepatectomy in rats

BACKGROUND

Liver regeneration is vital for the survival of patients submitted to extensive liver resection as a treatment of hepatocellular carcinoma (HCC). Sorafenib is a multikinase inhibitor of angiogenesis and cell division, both of which are integral components of liver regeneration. We investigated the effect of preoperative treatment with sorafenib, a drug used for the treatment of HCC, on liver regeneration and angiogenesis in healthy rats, after two-thirds partial hepatectomy (PH2/3).

METHODS

In total 48 Wistar rats received intragastric injections of sorafenib (30 mg/kg/d) or vehicle, underwent PH2/3, and were sacrificed at 48, 96 or 168 hours after that. The regenerative index of the liver remnant was studied, as well as the mitotic index. DNA synthesis and angiogenesis were estimated by immunohistochemistry for the Ki-67 and CD34 antigens, respectively.

RESULTS

Sorafenib reduced significantly the regenerative index at all time points but not the mitotic index at 48, 96 or 168 hours. Deoxyribonucleic acid (DNA) synthesis and angiogenesis were not affected significantly either.

CONCLUSIONS

Sorafenib, when administered preoperatively, reduces incompletely and transiently the regeneration of the liver after PH2/3 in rats. This could mean that sorafenib can be used as neoadjuvant treatment of patients with HCC prior to liver resection, but further experimental and clinical studies are needed to establish the safety of this treatment. Hippokratia 2015; 19 (3): 249-255.

Postoperative but not preoperative treatment with sorafenib inhibits liver regeneration in rats

BACKGROUND

Sorafenib, a multikinase inhibitor, has been shown to halt the growth of hepatocellular carcinoma. The aim of the present study was to investigate the effect of Sorafenib on liver regeneration in healthy rats.

METHODS

In two substudies we examined the effect of pre- or post-operative treatment with Sorafenib (15 mg/kg/d). Wistar rats (n = 120) received either Sorafenib (S) or placebo (P). After 70% partial hepatectomy, the rats were euthanized on postoperative days 2, 4, or 8. Body weight and liver weight were recorded and regeneration rate (RR) calculated. Hepatocyte proliferation was estimated by immunohistochemistry for Ki-67 antigen using unbiased stereological methods.

RESULTS

Eleven animals (9%) died after surgery. In the preoperative substudy, lower body weight gains during the gavage period in the S group were found. No difference between groups S and P regarding liver weight gain, liver RRs, and hepatocyte proliferation on postoperative days 2 and 4 were found. In the postoperative substudy, significantly lower values of liver weight gain, liver RRs, and hepatocyte proliferation were found in the S group.

CONCLUSIONS

In our rat model, Sorafenib did not increase posthepatectomy mortality. Postoperative treatment significantly impaired liver regeneration. Preoperative treatment impaired body weight during the gavage period, but was without effect on liver regeneration.

Sorafenib inhibits liver regeneration in rats

BACKGROUND

Sorafenib is a multikinase inhibitor with antiangiogenic and antiproliferative properties, approved for the treatment of hepatocellular carcinoma. The effect of Sorafenib on liver regeneration in healthy rats was investigated.

METHODS

Sixty Wistar rats received either Sorafenib (group S; 15 mg/kg) or placebo for 14 days prior to resection and until sacrifice. After a 70% partial hepatectomy, the rats were euthanized on post-operative days (POD) 2, 4 or 8. Hepatocyte proliferation was estimated by immunohistochemistry for Ki-67 antigen using stereological methods on sections prepared by systematic uniform random sampling.

RESULTS

Seven animals (12%) died after surgery. Death rates were similar in treated rats and controls. At hepatectomy, the body weight was significantly lower in group S rats. The liver weight and regeneration rates were lower in group S rats on PODs 2, 4 and 8. Hepatocyte proliferation was significantly lower in group S animals on PODs 2 and 4. Alanine aminotransferase ALAT was significantly higher in the Sorafenib-treated group on PODs 2, 4 and 8. Alkaline phosphatase ALP and bilirubin levels were similar in the two groups, although bilirubin was elevated in group S rats on POD 8.

CONCLUSION

In this rat model, Sorafenib did not increase post-hepatectomy mortality, but was associated with a significant impaired liver weight gain, regeneration rates and hepatocyte proliferation.

Kupffer cells potentiate liver sinusoidal endothelial cell injury in sepsis by ligating programmed cell death ligand-1

PD-1 and PD-L1 have been reported to provide peripheral tolerance by inhibiting TCR-mediated activation. We have reported that PD-L1-/- animals are protected from sepsis-induced mortality and immune suppression. Whereas studies indicate that LSECs normally express PD-L1, which is also thought to maintain local immune liver tolerance by ligating the receptor PD-1 on T lymphocytes, the role of PD-L1 in the septic liver remains unknown. Thus, we hypothesized initially that PD-L1 expression on LSECs protects them from sepsis-induced injury. We noted that the increased vascular permeability and pSTAT3 protein expression in whole liver from septic animals were attenuated in the absence of PD-L1. Isolated LSECs taken from septic animals, which exhibited increased cell death, declining cell numbers, reduced cellular proliferation, and VEGFR2 expression (an angiogenesis marker), also showed improved cell numbers, proliferation, and percent VEGFR2(+) levels in the absence of PD-L1. We also observed that sepsis induced an increase of liver F4/80(+)PD-1(+)-expressing KCs and increased PD-L1 expression on LSECs. Interestingly, PD-L1 expression levels on LSECs decreased when PD-1(+)-expressing KCs were depleted with clodronate liposomes. Contrary to our original hypothesis, we document here that increased interactions between PD-1(+) KCs and PD-L1(+) LSECs appear to lead to the decline of normal endothelial function-essential to sustain vascular integrity and prevent ALF. Importantly, we uncover an underappreciated pathological aspect of PD-1:PD-L1 ligation during inflammation that is independent of its normal, immune-suppressive activity.

Safety of liver resection for hepatocellular carcinoma after sorafenib therapy: a multicenter case-matched study

BACKGROUND

Liver resection can be considered in some hepatocellular carcinoma (HCC) patients who received sorafenib. The lack of clinical data about safety of resection after sorafenib treatment led us to assess its potential impact on perioperative course in a multicentric study.

METHODS

From 2008 to 2011, a total of 23 HCC patients who underwent liver resection after treatment with sorafenib (sorafenib group) were compared with 46 HCC patients (control group) matched for age, gender, underlying liver disease, tumor characteristics and type of resection. Patients received sorafenib for a median duration of 1 (range 0.2-11) months and drug was interrupted at least 7 days before surgery. End points were intraoperative (operative time, vascular clamping, blood loss and transfusion), and postoperative outcomes focusing on recovery of liver function.

RESULTS

In the sorafenib group, HCC was developed on F4 cirrhosis in 48 % and the rate of major resection was 44 %. Surgical procedure duration (280 vs. 240 min), transfusion rate (26 vs. 15 %), blood loss (400 vs. 300 mL) and vascular clamping (70 vs. 74 %) were similar in the two groups. Mortality was zero in the sorafenib group and one (2.1 %) in the control group (p = 1.000). The incidence of postoperative complications was 44 % in the sorafenib group and 59 % in the control group (p = 0.307). Recovery of liver function was similar in the two groups in terms of prothrombin time (90 vs. 81 %, p = 0.429) and bilirubin level (16 vs. 24 μmol/L, p = 102) at postoperative day 5.

CONCLUSIONS

No adverse effect of preoperative administration of sorafenib was observed during and immediately after liver resection for HCC.

Sorafenib prolongs liver regeneration after hepatic resection in rats

BACKGROUND

The multikinase inhibitor sorafenib inhibits angiogenesis and tumor cell proliferation. Sorafenib targets signaling pathways involved in liver regeneration. Previous works on regenerating mouse liver show differing results. We asked to which degree different lengths of sorafenib treatment would influence liver regeneration after hepatic resection in rats.

METHODS

Fischer-344 rats received intragastric injections of sorafenib (5-15 mg/kg/d), underwent a two-thirds partial hepatectomy (PH), and were sacrificed at different time points thereafter. Sorafenib treatment was stopped 0, 3, or 14 d after PH. Serum levels of aminotransferases and labeling indices of S-phase nuclei (bromodeoxyuridine and MIB-5) were analyzed, body and liver weights measured, and levels of phospho-ERK determined by Western blot.

RESULTS

Sorafenib increased aminotransferases and the number of S-phase nuclei at baseline, but decreased liver weights and levels of phospho-ERK 24 h after PH. The number of S-phase nuclei and mitotic indices decreased 48 h after PH and increased 7 d after PH in animals on sorafenib treatment. Relative liver weights were restored 5 d after PH in control rats, at 7 d in animals receiving sorafenib prior to surgery, at 10 d in rats where sorafenib was stopped 3 d after surgery, and after 14 d in rats on continuous treatment.

CONCLUSIONS

In this rat model, the regenerating liver adapted to the proliferation-inhibitory effect of sorafenib during continuous treatment. Sorafenib given after hepatic resection did not completely inhibit liver regeneration, but it prolonged the regenerative phase in proportion to the length of treatment.