Role of glycogen synthase kinase 3β in protective effect of propofol against hepatic ischemia-reperfusion injury. J Surg Res. 2013;185:388-398. [PMID: 23743186 DOI: 10.1016/j.jss.2013.05.004]

Role of Mitochondrial Pathways in Cell Apoptosis during He-Patic Ischemia/Reperfusion Injury

Hepatic ischemia-reperfusion injury is a major cause of post-operative hepatic dysfunction and liver failure after transplantation. Mitochondrial pathways can be either beneficial or detrimental to hepatic cell apoptosis during hepatic ischemia/reperfusion injury, depending on multiple factors. Hepatic ischemia/reperfusion injury may be induced by opened mitochondrial permeability transition pore, released apoptosis-related proteins, up-regulated B-cell lymphoma-2 gene family proteins, unbalanced mitochondrial dynamics, and endoplasmic reticulum stress, which are integral parts of mitochondrial pathways. In this review, we discuss the role of mitochondrial pathways in apoptosis that account for the most deleterious effect of hepatic ischemia/reperfusion injury.

GSK3 modulation in acute lung injury, myocarditis and polycystic kidney disease-related aneurysm

GSK3 are involved in different physical and pathological conditions and inflammatory regulated by macrophages contribute to significant mechanism. Infection stimuli may modulate GSK3 activity and influence host cell adaption, immune cells infiltration or cytokine expressions. To further address the role of GSK3 modulation in macrophages, the signal transduction of three major organs challenged by endotoxin, virus and genetic inherited factors are briefly introduced (lung injury, myocarditis and autosomal dominant polycystic kidney disease). As a result of pro-inflammatory and anti-inflammatory functions of GSK3 in different microenvironments and stages of macrophages (M1/M2), the rational resolution should be considered by adequately GSK3.

Propofol attenuates inflammatory response and apoptosis to protect d-galactosamine/lipopolysaccharide induced acute liver injury via regulating TLR4/NF-κB/NLRP3 pathway

OBJECTIVE

Propofol has been reported to be protective against liver injury due to its anti-inflammatory, anti-oxidative and anti-apoptotic activities. The purpose of this study was to examine the protective effects of propofol on d-galactosamine/lipopolysaccharide (d-GalN/LPS) induced acute liver injury.

METHODS

Mice were given an intraperitoneal injection of propofol before d-GalN/LPS treatment. Liver injury was confirmed by serum biochemical analysis and liver histopathological analysis. Relevant molecular events were determined by ELISA, western blot, and test kits. Cell apoptosis were evaluated by TUNEL assay.

RESULTS

The results showed that propofol significantly prevented d-GalN/LPS-induced liver damage by preventing associated increases of serum alanine transaminase (ALT) and aspartate transaminase (AST) and restoring liver histopathological changes. Propofol markedly inhibited the production of inflammatory cytokines and oxidative stress-related factors. Propofol markedly reduced hepatocyte apoptosis, decreased Bax, Bad, cleaved caspase-3 and increased Bcl-2 expression. Besides, NLRP3 inflammasome and TLR4/NF-κB pathway were inactivated under the treatment of propofol according to the expression of pathways-related proteins.

CONCLUSION

Taken together, propofol contributed to liver protection against d-GalN/LPS-induced liver injury in mice by inhibiting inflammation, oxidative stress and hepatocyte apoptosis through regulating TLR4/NF-κB/NLRP3 pathway.

Cox-2 Negatively Affects the Protective Role of Propofol against Hypoxia/Reoxygenation Induced Cardiomyocytes Apoptosis through Suppressing Akt Signaling

Nowadays, the prevention of severe myocardium injury resulting from myocardial ischemia/reperfusion injury (I/R) has been recognized as an important subject in the field of ischemic heart disease. In this study, H9c2 cardiomyocytes were exposed to cycles of hypoxia/reoxygenation (H/R) to mimic myocardial I/R injury. Western blot analysis and qRT-PCR were performed to detect the expression of Cox-2, Akt and p-Akt. Cell viability, LDH release and activity of Caspase-3 were assessed to determine the protective effect of propofol. The results proved that the protective effect of propofol for H/R challenged cardiomyocytes was associated with Akt phosphorylation. We also revealed that treatment of propofol suppressed the expression of Cox-2 in cardiomyocytes which was up-regulated after H/R treatment. Conversely, the over-expression of Cox-2 inhibited Akt phosphorylation while enhancing cardiomyocytes apoptosis. Interestingly, Akt activator exhibited similar protective effect with propofol and could diminish the influences brought by over-expression of Cox-2. Thus, it could be concluded that Cox-2 negatively affects the protective effect of propofol against hypoxia/reoxygenation induced cardiomyocyte apoptosis by suppressing Akt phosphorylation.

Addition of Berberine to Preservation Solution in an Animal Model of Ex Vivo Liver Transplant Preserves Mitochondrial Function and Bioenergetics from the Damage Induced by Ischemia/Reperfusion

Liver transplantation is a therapeutic regimen to treat patients with non-malignant end-stage liver diseases and malignant tumors of hepatic origin. The ischemia/reperfusion (I/R) injury in liver transplantation is associated with disruption of mitochondrial function in the hepatic parenchyma. Several studies have been conducted in animal models to identify pharmacological therapeutic strategies to minimize the injury induced by the cold/warm I/R in liver transplantation. Most of these studies were conducted in unrealistic conditions without the potential to be translated to clinical usage. Berberine (BBR) is a pharmacological compound with a potential protective effect of the mitochondrial function in the context of I/R. For the future clinical application of these pharmacological strategies, it is essential that a close resemblance exists between the methodology used in the animals models and real life. In this study, we have demonstrated that the addition of BBR to the preservation solution in an I/R setting preserves mitochondrial function and bioenergetics, protecting the liver from the deleterious effects caused by I/R. As such, BBR has the potential to be used as a pharmacological therapeutic strategy.

Multifaceted Roles of GSK-3 in Cancer and Autophagy-Related Diseases

GSK-3 is a ubiquitously expressed serine/threonine kinase existing as GSK-3α and GSK-3β isoforms, both active under basal conditions and inactivated upon phosphorylation by different upstream kinases. Initially discovered as a regulator of glycogen synthesis, GSK-3 is also involved in several signaling pathways controlling many different key functions. Here, we discuss recent advances regarding (i) GSK-3 structure, function, regulation, and involvement in several cancers, including hepatocarcinoma, cholangiocarcinoma, breast cancer, prostate cancer, leukemia, and melanoma (active GSK-3 has been shown to induce apoptosis in some cases or inhibit apoptosis in other cases and to induce cancer progression or inhibit tumor cell proliferation, suggesting that different GSK-3 modulators may address different specific targets); (ii) GSK-3 involvement in autophagy modulation, reviewing signaling pathways involved in neurodegenerative and liver diseases; (iii) GSK-3 role in oxidative stress and autophagic cell death, focusing on liver injury; (iv) GSK-3 as a possible therapeutic target of natural substances and synthetic inhibitors in many diseases; and (v) GSK-3 role as modulator of mammalian aging, related to metabolic alterations characterizing senescent cells and age-related diseases. Studies summarized here underline the GSK-3 multifaceted role and indicate such kinase as a molecular target in different pathologies, including diseases associated with autophagy dysregulation.

Unacylated ghrelin prevents mitochondrial dysfunction in a model of ischemia/reperfusion liver injury

Ischemia/reperfusion (I/R) injury is a common cause of liver dysfunction during hepatectomy, liver transplantation procedures and in generalized shock. Although effort has been dedicated to rescuing tissue damage in these clinical settings, there is still an urgent need for an effective treatment to protect the liver from the burden of I/R injury. In this study, we have investigated the potential clinical impact of unacylated-ghrelin (UnAG) in a liver I/R rat model. Particular attention has been paid to mitochondria. We demonstrate that UnAG was able to reduce the lag-phase time in response to ADP administration and increase oxygen consumption in ex vivo experiments using liver mitochondria recovered from rats subjected to I/R. Moreover, we found that UnAG rescued the expression of a key regulator of mitochondrial morphology and electron transport chain function; the optic atrophy 1 (Opa1) protein. Cytochrome c oxidase (COX), ATP synthase (complex V) activity and mitochondrial permeability transition pore (mPTP) opening were also affected by UnAG administration in vivo. An in vitro, hepatic I/R model was used to validate these data. We demonstrate that UnAG upregulates the expression of Cox subunit IV (CoxIV) and increases cellular ATP content. This results in Bcl-2 upregulation and protection against apoptosis. Opa1 silencing shows that Opa1 is crucial for a UnAG-induced increase in cellular ATP content, apoptosis resistance, Bcl-2 and CoxIV expression. Finally, we show that UnAG improves Opa1's interaction with MIC60 in the I/R setting, hinting at its role in cristae shape regulation. Our results demonstrate that UnAG administration rescues the intrinsic mitochondrial pathway triggered by I/R damage. Opa1's contribution in mediating this effect is also reported. This suggests that UnAG can interfere with mitochondrial dysfunction, via Opa1, in a preclinical liver I/R model. We therefore provide the rationale for exploiting UnAG as an alternative means to rescuing mitochondrial damage and organ dysfunction.

Impact of propofol on renal ischemia/reperfusion endoplasmic reticulum stress

Purpose:

To investigate the protective mechanisms of propofol (Pro) on renal ischemia/reperfusion (I/R) injury by studying its impact on renal I/R endoplasmic reticulum stress.

Methods:

Eighteen male Sprague-Dawley rats (SD rats) were randomly divided into three groups: the I/R group, the Pro pretreatment group, and the control group, and corresponding treatments were performed. The levels of serum creatinine (Cr) and blood urea nitrogen (BUN) of each group were detected. The expression levels of CCAAT-enhancer-binding protein (C/EBP) homology protein (CHOP) and caspase-12 protein within renal tissue samples were detected by western blot.

Results:

The periodic acid-Schiff (PAS) staining was performed to observe the morphological changes within the renal tissues, and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay was performed to detect the presence of renal apoptosis. The Pro pretreatment significantly reduced the serum Cr and BUN levels, as well as the expressions levels of CHOP and caspase-12 protein inside the kidney of I/R rats, improving renal pathological injury and reducing the I/R-induced renal apoptosis.

Conclusion:

Propofol could downregulate the expression of stress-apoptotic proteins CHOP and caspase-12 in the endoplasmic reticulum, thus reducing renal I/R injury.

Biochemical targets of drugs mitigating oxidative stress via redox-independent mechanisms

Acute or chronic oxidative stress plays an important role in many pathologies. Two opposite approaches are typically used to prevent the damage induced by reactive oxygen and nitrogen species (RONS), namely treatment either with antioxidants or with weak oxidants that up-regulate endogenous antioxidant mechanisms. This review discusses options for the third pharmacological approach, namely amelioration of oxidative stress by 'redox-inert' compounds, which do not inactivate RONS but either inhibit the basic mechanisms leading to their formation (i.e. inflammation) or help cells to cope with their toxic action. The present study describes biochemical targets of many drugs mitigating acute oxidative stress in animal models of ischemia-reperfusion injury or N-acetyl-p-aminophenol overdose. In addition to the pro-inflammatory molecules, the targets of mitigating drugs include protein kinases and transcription factors involved in regulation of energy metabolism and cell life/death balance, proteins regulating mitochondrial permeability transition, proteins involved in the endoplasmic reticulum stress and unfolded protein response, nuclear receptors such as peroxisome proliferator-activated receptors, and isoprenoid synthesis. The data may help in identification of oxidative stress mitigators that will be effective in human disease on top of the current standard of care.

Pre-conditions for eliminating mitochondrial dysfunction and maintaining liver function after hepatic ischaemia reperfusion

The liver, the largest organ with multiple synthesis and secretion functions in mammals, consists of hepatocytes and Kupffer, stem, endothelial, stellate and other parenchymal cells. Because of early and extensive contact with the external environment, hepatic ischaemia reperfusion (IR) may result in mitochondrial dysfunction, autophagy and apoptosis of cells and tissues under various pathological conditions. Because the liver requires a high oxygen supply to maintain normal detoxification and synthesis functions, it is extremely susceptible to ischaemia and subsequent reperfusion with blood. Consequently, hepatic IR leads to acute or chronic liver failure and significantly increases the total rate of morbidity and mortality through multiple regulatory mechanisms. An increasing number of studies indicate that mitochondrial structure and function are impaired after hepatic IR, but that the health of liver tissues or liver grafts can be effectively rescued by attenuation of mitochondrial dysfunction. In this review, we mainly focus on the subsequent therapeutic interventions related to the conservation of mitochondrial function involved in mitigating hepatic IR injury and the potential mechanisms of protection. Because mitochondria are abundant in liver tissue, clarification of the regulatory mechanisms between mitochondrial dysfunction and hepatic IR should shed light on clinical therapies for alleviating hepatic IR‐induced injury.

Protective effect of propofol preconditioning on ischemia-reperfusion injury in human hepatocyte

BACKGROUND

Blood reperfusion after ischemia is the main measure to restore cell function. This study was aimed to explore the effect of propofol on rat and cell models of liver ischemia-reperfusion (I/R) injury, and to investigate its possible mechanism.

METHODS

Wistar rats were divided into four groups: control group, sham group, I/R group, and propofol group. Human hepatocyte HL7702 was divided into six groups: control group, I/R group and propofol (5, 10, 20 and 40 µmol/L) groups. After the animal and cell models were established, the alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA) and adenosine triphosphate (ATP) levels in liver tissues and hepatocytes were measured. Cell viability and apoptosis of hepatocytes were respectively determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. Furthermore, the expressions of apoptosis-related proteins in hepatocytes were determined by Western blot analysis.

RESULTS

ALT, AST and MDA levels were all decreased significantly, and the ATP level was increased significantly in propofol group compared with that in I/R group in both liver tissues and hepatocytes. Additionally, cell viability of hepatocytes in propofol group was higher than that in I/R group, while the percentage of apoptotic cells in propofol group was less than that in I/R group. Moreover, the expression of caspase-3 decreased and the expression of Bcl-2 increased significantly after propofol preconditioning.

CONCLUSIONS

Our findings suggested that propofol preconditioning might be an effective strategy for protecting the liver from I/R injury, which might provide a scientific basis for clinical application.

Propofol but not sevoflurane prevents mitochondrial dysfunction and oxidative stress by limiting HIF-1α activation in hepatic ischemia/reperfusion injury

Mitochondrial dysfunction, reactive oxygen species (ROS) production and oxidative stress during reperfusion are determinant in hepatic ischemia/reperfusion (I/R) injury but may be impacted by different anesthetic agents. Thus, we aimed at comparing the effects of inhaled sevoflurane or intravenous propofol anesthesia on liver mitochondria in a rodent model of hepatic I/R injury. To this, male Wistar rats underwent I/R surgery using sevoflurane or propofol. In the I/R model, propofol limited the raise in serum aminotransferase levels as compared to sevoflurane. Mitochondrial oxygen uptake, respiratory activity, membrane potential and proton leak were altered in I/R; however, this impairment was significantly prevented by propofol but not sevoflurane. In addition, differently from sevoflurane, propofol limited hepatic I/R-induced mitochondria H2O2 production rate, free radical leak and hydroxynonenal-protein adducts levels. The I/R group anesthetized with propofol also showed a better recovery of hepatic ATP homeostasis and conserved integrity of mitochondrial PTP. Moreover, hypoxia-inducible factor 1 alpha (HIF-1α) expression was limited in such group. By using a cell model of desferoxamine-dependent HIF activation, we demonstrated that propofol was able to inhibit apoptosis and mitochondrial depolarization associated to HIF-1α action. In conclusion, hepatic I/R injury induces mitochondrial dysfunction that is not prevented by inhaled sevoflurane. On the contrary, propofol reduces liver damage and mitochondrial dysfunction by preserving respiratory activity, membrane potential and energy homeostasis, and limiting free radicals production as well as PTP opening. These hepatoprotective effects may involve the inhibition of HIF-1α.

The effect of propofol on the expression of rabbit ischemia reperfusion injury-related proteins

To investigate the effect of propofol on the expression of rabbit ischemia-reperfusion injury-related proteins and the mechanism involved. Thirty healthy adult New Zealand rabbit were selected. After establishment of liver I/R model, the rabbits were divided into group A (sham operation group), group B (control group using saline), and group C (propofol group) with ten rabbits in each group. The total protein concentration, differentially expressed protein spots and the difference of apoptotic proteins expression levels among the three groups were compared. The total protein concentrations in group A, B, and C were 0.778, 0.835, and 0.765 μg/μl, respectively, and the protein concentration in group B was significantly higher than group A and C (p < 0.05), with no significant difference between group A and C (p > 0.05); results analyzed by PDQuest software showed that the average number of protein spots and matching ratio had no significant difference among the three groups (p > 0.05); MALDI-TOF-MS mass spectrometry identified 16 differentially expressed protein spots; the numbers of Caspase-3 positive cells in group B and C were significantly higher than those in group A, and the numbers of Bcl-2 and Bax positive cells in group B and C were significantly lower than those in group A (p < 0.05); the number of Capase-3 positive cells in group C was significantly higher than those in group B, and the number of Bcl-2 positive cells in group C was significantly lower than those in group B (p < 0.05). The numbers of Bax positive cells had no significant difference between group B and C (p > 0.05); densities of Caspase-3, Bcl-2 and Bax in group B and C were significantly higher than those in group A (p < 0.05); Western blotting results from the comparison of the number of positive cells between group B and C was in accordance to the result obtained from immunohistochemistry. After I/R injury in rabbit, there was deregulation of various proteins such as Caspase-3, Bcl-2 and Bax, which was an important factor contributing to liver injury even systematic disease. Propofol could regulate the expression of I/R injury-related proteins and inhibit the attack of free radical to liver, having a remarkable advantage in preventing I/R injury and controlling the development of I/R injury. This study provides an effective theoretical basis for the prevention and treatment of I/R injury.

Propofol reduces liver dysfunction caused by tumor necrosis factor-α production in Kupffer cells

PURPOSE

The present study, conducted in rats, investigated whether propofol attenuates lipopolysaccharide (LPS)-triggered liver dysfunction via regulation of tumor necrosis factor (TNF)-α production in activated Kupffer cells.

METHODS

Rats received LPS (500 μg/kg) under Urethane™ sedation (1 g/kg) in combination with propofol (5 mg/kg/h) or Intralipid™ from 1 h before to 6 h after LPS administration. Some rats were treated with 10 mg/kg gadolinium chloride (GdCl3) to induce Kupffer cell depletion. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), TNF-α mRNA and protein expression, caspase-3 activation and apoptosis were evaluated in hepatocytes. Immunofluorescence staining revealed expression of the pan-macrophage marker CD68 as well as TNF-α in Kupffer cells.

RESULTS

ALT and AST serum levels increased approximately four-fold in LPS-exposed rats compared with Intralipid™-treated rats at 6 h after LPS administration, whereas propofol and GdCl3 reduced the LPS-induced increases. LPS simultaneously augmented TNF-α expression in Kupffer cells, followed by increased caspase-3 activity and apoptosis in hepatocytes. Immunofluorescence staining and immunoblotting assay showed that TNF-α expression in Kupffer cells was inhibited by propofol and GdCl3, resulting in a reduction of caspase-3 activity and apoptosis in LPS-treated rat hepatocytes.

CONCLUSIONS

Propofol (5 mg/kg/h) attenuated LPS-triggered liver dysfunction via inhibition of TNF-α production in activated Kupffer cells. These results suggest that propofol is capable of inhibiting inflammation-induced liver dysfunction in vivo.

Molecular pathways in protecting the liver from ischaemia/reperfusion injury: a 2015 update

Ischaemia/reperfusion injury is an important cause of liver damage during surgical procedures such as hepatic resection and liver transplantation, and represents the main cause of graft dysfunction post-transplantation. Molecular processes occurring during hepatic ischaemia/reperfusion are diverse, and continuously include new and complex mechanisms. The present review aims to summarize the newest concepts and hypotheses regarding the pathophysiology of liver ischaemia/reperfusion, making clear distinction between situations of cold and warm ischaemia. Moreover, the most updated therapeutic strategies including pharmacological, genetic and surgical interventions, as well as some of the scientific controversies in the field are described.

Role of sirtuins in ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) remains an unresolved and complicated situation in clinical practice, especially in the case of organ transplantation. Several factors contribute to its complexity; the depletion of energy during ischemia and the induction of oxidative stress during reperfusion initiate a cascade of pathways that lead to cell death and finally to severe organ injury. Recently, the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases has gained increasing attention from researchers, due to their involvement in the modulation of a wide variety of cellular functions. There are seven mammalian sirtuins and, among them, the nuclear/cytoplasmic sirtuin 1 (SIRT1) and the mitochondrial sirtuin 3 (SIRT3) are ubiquitously expressed in many tissue types. Sirtuins are known to play major roles in protecting against cellular stress and in controlling metabolic pathways, which are key processes during IRI. In this review, we mainly focus on SIRT1 and SIRT3 and examine their role in modulating pathways against energy depletion during ischemia and their involvement in oxidative stress, apoptosis, microcirculatory stress and inflammation during reperfusion. We present evidence of the beneficial effects of sirtuins against IRI and emphasize the importance of developing new strategies by enhancing their action.