Effect of nebivolol on liver regeneration in an experimental 70% partial hepatectomy model

β2-adrenergic receptor promotes liver regeneration partially through crosstalk with c-met

The β₂-adrenergic receptor (β₂AR) is a G protein-coupled receptor (GPCR) that mediates the majority of cellular responses to external stimuli. Aberrant expression of β₂AR results in various pathophysiological disorders, including tumorigenesis, but little is known about its role in liver regeneration. This study aims to investigate the impact and the underlying mechanism of β₂AR in liver regeneration. Here, we found that β₂AR was upregulated during liver regeneration induced by 70% PH. Deletion of β₂AR in mice resulted in 62% mortality 2 days post-PH, decreased proliferative marker expression and impaired liver function throughout regeneration. Moreover, AAV8-mediated overexpression of β₂AR in hepatocytes accelerated the regeneration process and increased target gene expression. Mechanistically, β₂AR recruited G-protein-coupled receptor kinase 2 (GRK2) to the membrane and then formed a complex with c-met to transactivate c-met signaling, which triggered downstream extracellular regulated protein kinase (ERK) signaling activation and nuclear translocation. Inhibition of c-met with SU11274 or ERK with U0126 decreased β₂AR overexpression-induced hepatocyte proliferation. Our findings revealed that β₂AR might act as a critical mediator regulating liver regeneration by crosstalk with c-met and activation of ERK signaling.

Nebivolol alleviates liver damage caused by methotrexate via AKT1/Hif1α/eNOS signaling

Despite the wide clinical indications, methotrexate (MTX) use is limited because of serious side effects including liver toxicity. MTX was shown to cause tissue damage by mainly oxidative stress and also inflammation and apoptosis. Thus, Nebivolol (NEB) which has antioxidant and antiapoptotic properties were thought to be effective against MTX-induced injury. This study aimed to evaluate the effects of NEB on MTX-induced liver toxicity via AKT/Hypoxia-Inducible Factor 1 Alpha (HIF1α)/Endothelial Nitric Oxide Synthase (eNOS) signaling pathways. Rats were divided into three groups as control, MTX, and NEB. A single dose of MTX (20 mg/kg intraperitoneally) was given to the rats on the first day of the experiment and NEB (10 mg/kg, daily by oral gavage) was given to the treatment group for a week. At the end of the experiment, bloods were taken for aspartate transaminase (AST), alanine aminotransferase (ALT), and total bilirubin (T-BIL) analyses. Liver tissues were harvested for biochemical (total oxidant status (TOS) and total antioxidant status (TAS), genetic (PCR analyses for AKT1, eNOS, and HIF1a), and histological (Hemotoxylin-Eosin, Masson Trichome, Periodic Acid Schiff-Asien Blue, reticulin for histological, and CD3 for immunohistochemical staining) analyses. MTX increased the levels of TOS values, AST, ALT, T-BIL levels and decreased the expressions of AKT/HIF1α/eNOS. NEB treatment reversed all these changes markedly via decreasing inflammation by nitric oxid (NO) production. In conclusion, NEB treatment significantly preserves the liver by decreasing oxidant levels and inflammatory parameters through HIF1α/eNOS signaling. Due to the antioxidant properties of NEB, it can be used in other liver injury models sharing the same pathway.

May dexpanthenol, platelet-rich plasma, and thymoquinone provide new hope to maintain liver regeneration after partial hepatectomy?

BACKGROUND/AIMS

Complete liver regeneration may not always be possible after liver injuries and/or partial liver resection. The present study investigated the effects of dexpanthenol, platelet-rich plasma (PRP), and thymoquinone on liver regeneration in rats after partial hepatectomy (PH).

MATERIALS AND METHODS

A total of 34 Wistar albino rats, each weighing 250-280 g, were randomly separated into four groups. PH was performed, and except for the control group, intraperitoneal dexpanthenol, PRP, or thymoquinone was administered to the relevant groups for 7 days. All rats were then sacrificed, and the liver tissues were examined histopathologically and biochemically.

RESULTS

PRP reduced all oxidant-antioxidant parameters in rats that experienced liver regeneration, but did not create histopathological improvement in the liver tissue. Dexpanthenol had a histopathological improving effect on the liver tissue, but had no effect on biochemical parameters. Thymoquinone showed no histopathological or biochemical effects on liver regeneration.

CONCLUSION

Although dexpanthenol did not affect biochemical oxidative parameters, it was considered to have improving effects on liver regeneration histopathologically. In addition, it was thought that PRP may be used for treatment of ischemia-reperfusion injury and cholestatic damage of the liver. Nevertheless, further studies are required on these subjects.

Pine ( Pinus densiflora ) needle extract could promote the expression of PCNA and Ki-67 after partial hepatectomy in rat

Purpose

To investigate the effects of pine needle extract (PNE) on the expression of proliferating cell nuclear antigen (PCNA) and Ki-67 during liver regeneration induced by 70% partial hepatectomy (PH) in rat.

Methods

Forty-eight male rats (SD, 7 weeks) had surgery (70% PH). They were randomly divided into two groups. PH + PNE group was only provided PNE diluted in water (10%) for drinking and PH group was provided water from 5 days before surgery to the time of sacrifice. PNE was made by pressing and filtering. Animals were sacrificed at 12h, 24h, 36h, 60h, 84h, 168h after PH, respectively. The expressions of PCNA and Ki-67 were determined as proliferation indices.

Results

Immunohistochemistry turned out to increase the expression of PCNA and Ki-67. PCNA expression of PH+PNE group increased up to twice of that of PH group. Western blot also seemed to increase the PCNA expression. These results indicated the promotion of cell proliferation in liver tissue and hepatic regeneration.

Conclusions

Pine needle extract stimulates the expression of some mitotic proteins during liver regeneration induced by 70% PH in rats. It suggests that administration of pine needle extract could accelerate the liver regeneration after partial hepatectomy.

Protective role of nebivolol in cadmium-induced hepatotoxicity via downregulation of oxidative stress, apoptosis and inflammatory pathways

Cadmium (Cd) intoxication in human occurs through inhalation of cigarette smoke and ingestion of contaminated water and food. We investigated the role of nebivolol (NEB) in Cd induced hepatotoxicity. In our study; NEB was given as (10 mg/kg/d) orally to rats for 6 weeks, in the presence or absence of hepatotoxicity induced by oral administration of Cd (7 mg/kg/d) for 6 weeks. Levels of serum liver enzyme biomarkers; alanine transaminase (ALT), aspartate transaminase (AST) and serum total antioxidant capacity (TAC) were measured. In addition; mean arterial pressure and total cholesterol levels were measured. Hepatic superoxide dismutase (SOD) and malondialdehyde (MDA) were detected. Hepatic histopathological features, inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) immunoexpressions were evaluated. Tumor necrosis factor alpha (TNF-α) and B-cell lymphoma-2 (Bcl-2) mRNA gene expressions were detected using real time-PCR (rt-PCR). Our results showed marked increase in all measured parameters except SOD, TAC, eNOS immunoexpression and Bcl2 mRNA gene expression which decreased in Cd induced hepatotoxicity group. NEB showed marvelous protective effect against Cd induced changes. NEB decreased liver enzymes (ALT and AST), mean arterial pressure, total cholesterol levels, MDA, iNOS immunoexpression and TNF-α gene expression but significantly increased SOD, TAC, eNOS immunoexpression and Bcl-2 gene expression. Moreover; NEB markedly improved the histopathological changes induced by Cd. These findings prove the antioxidant, anti-apoptotic and anti-inflammatory properties of NEB and its protective role in Cd induced hepatotoxicity.

Factors Affecting Liver Regeneration in Living Donors After Hepatectomy

Background

The safety of living liver donors is the paramount priority of liver transplantation surgeons. The liver has an effective regeneration capacity. The regeneration rate of the liver remnant in living liver donors provides much information useful in liver surgery. The outcome of the remnant liver after hepatectomy can be affected by many different perioperative factors.

Material/Methods

A total of 46 patients were enrolled in the study. Retrospective clinical data, including preoperative and postoperative early and late computed tomography liver volumetry measurements, estimated resection volumes, resected liver weights, and postoperative laboratory values, were statistically evaluated according to the liver resection type.

Results

No significant difference was detected in age, sex, calculated and computed tomography estimated total liver volume, intraoperative Hb decrease, postoperative complications, or postoperative portal vein flow rate. Postoperative liver enlargement rates were significant higher in the right hemihepatectomy (RHH) group than in the left lateral sectionectomy (LLS) group. The size of the liver remnant or graft has a major effect on regeneration rate. Postoperative biliary leakage did not have any significant effect on liver regeneration. No post-hepatectomy liver failure was detected among the liver donors.

Conclusions

Liver hypertrophy depends on the extent of liver resection. The cause of volume decrease in the LLS group after hepatectomy in our series appears to be the gradual atrophy of liver segment 4. RHH and LLS surgeries differ from each other in terms of resected liver volume, as well as inflammatory activity, and the latter appears to affect liver regeneration.