Emulsified isoflurane preconditioning protects isolated rat Kupffer cells against hypoxia/reoxygenation-induced injury

Ligustrazine improves the compensative effect of Akt survival signaling to protect liver Kupffer cells in trauma-hemorrhagic shock rats

Trauma-hemorrhagic shock (THS) is a medical emergency that is encountered by physicians in the emergency department. Chuan Xiong is a traditional Chinese medicine and ligustrazine is a natural compound from it. Ligustrazine improves coronary blood flow and reduces cardiac ischemia in animals through Ca2+ and ATP-dependent vascular relaxation. It also decreases the platelets' bioactivity and reduces reactive oxygen species formation. We hypothesized that ligustrazine could protect liver by decreasing the inflammation response, protein production, and apoptosis in THS rats. Ligustrazine at doses of 100 and 1000 μg/mL was administrated in Kupffer cells isolated from THS rats. The protein expressions were detected via western blot. The THS showed increased inflammation response proteins, mitochondria-dependent apoptosis proteins, and had a compensation effect on the Akt pathway. After ligustrazine treatment, the hemorrhagic shock Kupffer cells decreased inflammatory response and mitochondria-dependent apoptosis and promoted a more compensative effect of the Akt pathway. It suggests ligustrazine reduces inflammation response and mitochondria-dependent apoptosis induced by THS in liver Kupffer cells and promotes more survival effects by elevating the Akt pathway. These findings demonstrate the beneficial effects of ligustrazine against THS-induced hepatic injury, and ligustrazine could be a potential medication to treat the liver injury caused by THS.

CX3CL1 represses autophagy via CX3CR1/ CaMKIIδ/HDAC4/Rubicon axis and exacerbates chronic intermittent hypoxia induced Kupffer cell apoptosis

BACKGROUND

Nocturnal hypoxemia is an established factor in the pathogenesis and exacerbation of term metabolic (dysfunction) associated fatty liver disease (MAFLD). Kupffer cells (KCs) are resident macrophages in the liver, and their activity is closely related to the progress of MAFLD. KC insufficient autophagy is involved in MAFLD pathogenesis. Herein, the regulatory mechanism of KC autophagy under chronic intermittent hypoxia (CIH) condition was investigated.

METHODS

Primary KCs and hepatic stellate cells (HSCs) were isolated from mouse liver. Immunofluorescence was employed to detect immunofluorescence intensity of LC3 protein and HDAC4 distribution. KC apoptosis was measured by TUNEL staining. Dual-luciferase reporter and ChIP assays were performed to analyze the interactions between HDAC4, MEF2C and RUBCN.

RESULTS

Herein, our results revealed that CIH-induced increased CX3CL1 in HSCs inhibited KC autophagy and promoted cell apoptosis by interacting with CX3CR1. Meanwhile, CX3CL1 treatment inhibited KC autophagy (p < 0.001, fold change: 0.059) and promoted cell apoptosis (p < 0.001, fold change: 8.18). Rubicon knockdown promoted KC autophagy (p < 0.001, fold change: 2.90) and inhibited cell apoptosis (p < 0.05, fold change: 0.23), while these effects were reversed by CX3CL1 treatment (p < 0.01, fold change: 6.59; p < 0.001, fold change: 0.35). Our mechanistic experiments demonstrated that HDAC4 overexpression transcriptionally inhibited RUBCN expression by interacting with MEF2C, thereby promoting KC autophagy and inhibiting cell apoptosis. Moreover, CaMKIIδ inhibition promoted the translocation of HDAC4 from the cytosol to the nucleus to promote KC autophagy and inhibit the apoptosis.

CONCLUSION

Taken together, CIH-induced increased CX3CL1 expression in HSCs inhibited KC autophagy and promoted apoptosis by regulating the CX3CR1/ CaMKIIδ/HDAC4/Rubicon axis.

The Bioequivalence of Emulsified Isoflurane With a New Formulation of Emulsion: A Single-Center, Single-Dose, Double-Blinded, Randomized, Two-Period Crossover Study

Background: Emulsified isoflurane is a novel intravenous general anesthetic obtained by encapsulating isoflurane molecules into emulsion. The formulation of emulsion has been improved according to the latest regulations of the China Food and Drug Administration. This study was designed to compare the bioequivalence of the new and previous formulation emulsion of isoflurane.

Methods: In a single-center, single-dose, double-blinded, randomized, two-period crossover study, healthy volunteers received intravenous injection of 30 mg/kg of isoflurane with either previous formulation of emulsion isoflurane (PFEI) or new formulation of emulsion isoflurane (NFEI). Arterial and venous blood samples were obtained for geometric mean test/reference ratios of C_max, AUC_0-t, and AUC_0-∞, as well as their 90% confidence interval (CI90) as the primary outcome. The secondary outcomes were safety measurements such as vital signs, 12-lead electrocardiography, adverse effects, and laboratory tests; and anesthesia efficacy was assessed by Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) score, bispectral index (BIS), and loss/recovery of eyelash reflex.

Results: 24 subjects were eligible, of which 21 completed the whole experiment (NFEI n = 21, PFEI n = 23). Arterial geometric mean test/reference ratios of C_max, AUC_0-t, and AUC_0-∞ were 104.50% (CI90 92.81%–117.65%), 108.23% (94.51%–123.96%), and 106.53% (93.94%∼120.80%), respectively. The most commonly seen adverse effects for NFEI and PFEI were injection pain (38.1% vs. 34.8%), hypotension (19.0% vs. 13.0%), apnea (14.3% vs. 17.4%), and upper airway obstruction (14.3% vs. 13.0%). No severe adverse effect was observed. The effectiveness of general anesthesia was similar between the two formulations.

Conclusion: The CI90 of C_max, AUC_0-t, AUC_0-∞, NFEI, and PFEI were within the range of 80%–125%, suggesting bioequivalence between NFEI and PFEI. The safety and anesthesia effectiveness were also similar.

[Isoflurane preconditioning inhibits caspase-11-related noncanonical pyroptosis pathway to alleviate hepatic ischemia-reperfusion injury in mice]

OBJECTIVE

To study the protective effect of isoflurane preconditioning on hepatic ischemia-reperfusion (I/R) injury mediated by the noncanonical pyroptosis pathway.

METHODS

Thirty C57BL/6 mice were randomly divided into sham-operated group, isoflurane group and I/R group, and in the latter two groups, hepatic I/R injury was induced by clamping the portal vein for 30 min. In isoflurane group, the mice were pretreated with 1.4% isoflurane 30 min before the surgery. The protective effect of isoflurane preconditioning against hepatic I/R injury was evaluated by assessing the pathological score of HE staining of the liver tissue and serum ALT and AST levels. Serum IL-1β and IL-18 levels and the protein expression of GSDMS were detected by ELISA and Western blotting to evaluate the inhibitory effect of isoflurane preconditioning on pyroptosis. Western blotting and immunofluroescence were used to detect the protein expression of caspase-11 in the liver tissues to evaluate the inhibitory effect of isoflurane preconditioning on noncanonical pyroptosis pathway.

RESULTS

The Suzuki's score of the liver tissue was significantly higher in I/R group than in the sham group (P &lt; 0.05), while the score in the isoflurane group was significantly lower than that in the I/R group (P &lt; 0.05). Serum ALT and AST levels significantly increased in the sham group (P &lt; 0.05), and were significantly lower in isoflurane group than in I/R group (P &lt; 0.05). The serum levels of IL-1β and IL-18 were significantly higher in I/R group than in sham group (P &lt; 0.05), and were significantly lower in isoflurane group than in I/R group (P &lt; 0.05). The expression of GSDMD in the I/R group was significantly higher than that in sham group, and was significantly lower in isoflurane group than in I/R group (P &lt; 0.05). The hepatic expression of caspase-11 was significantly higher in I/R group than in sham group (P &lt; 0.05), and was significantly lower in isoflurane group than in I/R group (P &lt; 0.05).

CONCLUSIONS

Isoflurane preconditioning has protective effect against hepatic I/R injury, which is related to the inhibition of the noncanonical pyroptosis pathway.

Stable perfluorocarbon emulsions for the delivery of halogenated ether anesthetics

BACKGROUND

Research into injectable volatile anesthetics has been ongoing for approximately 40 years, with limited success, in an attempt to address the deficiencies of inhalational anesthesia. The purpose of this work was to formulate and optimize volatile anesthetic carrier emulsions based on our prior work in perfluorocarbon emulsions.

METHODS

Perfluorocarbons were screened for their volatilty and emulsion stability. Optimal anesthetic emulsions were manufactured by high pressure homogenization of a select, clinically relevant perfluorocarbon, isoflurane and a surfactant-containing aqueous phase. Longitudinal particle size, polydispersity and isoflurane content analysis was performed. Observational studies of in vivo efficacy and safety were performed in 225-300 g Lewis Rats (n = 34) with blood chemistry and post study tissue pathology analysis.

RESULTS

Emulsion particle size and isolflurane content in select emulsions were stable at room temperature greater than 300 days. This stability was depedent on perfluorocarbon molecular weight and boiling point. in vivo, emulsions demonstrated a rapid onset and offset. Variability in onset metrics (loss of righting reflex, pain reflexes and time to recovery) was less than 40% amongst individual emulsion preparations (n = 9) utilized in induction trials. No adverse effects due to the intravenous administration of emulsions were observed in blood chemistry results or post-study pathological examination.

CONCLUSIONS

These formulations showed stability, safety and efficacy. In addition to induction and general anesthesia, these emulsions could have utility in global health or in military applications where equipment and resources are limited.

Effect of lipopolysaccharide on proliferation, secretion and ultrastructure of murine liver Kupffer cells under high glucose conditions

AIM

To investigate the effect of lipopolysaccharide (LPS) on the proliferation, secretion and ultrastructure of liver Kupffer cells (KCs) under high glucose conditions.

METHODS

Murine liver KCs were cultured, amplified, and then randomly divided into a high glucose group [(HG), 25.0 mmol/L D-glucose], a normal glucose group [(CON), 11.1 mmol/L D-glucose], a LPS + high glucose group [(LPS-HG), 25.0 mmol/L D-glucose], and a LPS + normal glucose group [(LPS-CON), 11.1 mmol/L D-glucose)]. The KCs in each group were cultured for 24 h, and then LPS was added for the LPS-HG and LPS-CON groups. After 6 h of continuous cultivation, cell proliferation and cell cycle were detected by MTT colorimetric assay and flow cytometry, respectively. Cell supernatants were collected to determine the levels of tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β and IL-6 by Luminex xMAP technique. The ultrastructure of KCs was observed by transmission electron microscopy (TEM).

RESULTS

MTT colorimetric assay showed that the optical density (OD) of murine liver KCs treated with LPS for 6 h under high glucose conditions increased significantly, but the OD values decreased significantly in the HG and LPS-HG groups compared with those of the CON and LPS-CON groups (P < 0.05). Flow cytometry revealed that high glucose arrested the cell cycle in G0/G1 phase; the percentage of G0/G1 phase cells decreased and that of S + G2/M phase cells increased significantly (P < 0.01) after KCs were treated with LPS for 6. The Luminex xMAP assay showed that the levels of TNF-α, IL-1β and IL-6 increased significantly after murine liver KCs were treated with LPS for 6 h under high glucose conditions, and the changes in TNF-α and IL-1β were more obvious. TEM revealed obvious ultrastructural alterations of KCs treated with LPS for 6 h under high glucose conditions. A large number of autophagosomes were observed in the LPS-HG group, and only few were noted in the HG group. Only vacuolar degenerations were visible in the CON and LPS-CON groups.

CONCLUSION

LPS can activate and enhance the proliferation and secretion of murine liver Kupffer cells under high glucose conditions. Both LPS and hyperglycemia can induce ultrastructural alterations of KCs including autophagy.

Autophagy-deficient Kupffer cells promote tumorigenesis by enhancing mtROS-NF-κB-IL1α/β-dependent inflammation and fibrosis during the preneoplastic stage of hepatocarcinogenesis

As a cellular degradation mechanism, autophagy exerts crucial and complicated effects on HCC development. Liver non-parenchymal cells, including hepatic resident macrophage Kupffer cells, also play important roles in this process. However, most associated studies have focused on the influence of the autophagy level in hepatic cells and HCC cells, but not liver non-parenchymal cells. Based on our previous study, we confirmed that Atg5 silence in the liver during the preneoplastic stage facilitated liver fibrosis, inflammation and, ultimately, tumorigenesis. We further found that autophagy deficiency promotes the production of inflammatory and fibrogenic factors in macrophages. Moreover, Kupffer cell depletion rescued the tumor-promoting effect of autophagy deficiency during the preneoplastic stage. In autophagy-deficient macrophages, mitochondrial ROS mediated inflammation- and fibrosis-promoting effects by increasing IL1α/β production via enhancing NF-κB-associated pathways. Both blocking of mitochondrial ROS and blocking the IL1 receptor stopped the promotion of fibrosis, inflammation and tumorigenesis resulting from Atg5 knockdown during the preneoplastic stage. In conclusion, autophagy-deficient Kupffer cells promote liver fibrosis, inflammation and, finally, hepatocarcinogenesis during the preneoplastic stage by enhancing mitochondrial ROS- NF-κB-IL1α/β pathways.

Emulsified isoflurane treatment inhibits the cell cycle and respiration of human bronchial epithelial 16HBE cells in a p53-independent manner

Emulsified isoflurane (EIso), as a result of its rapid anesthetic induction, recovery and convenience, is widely used as a novel intravenous general anesthetic. Treatment with EIso can reduce injuries caused by ischemia/reperfusion (I/R) to organs, including the heart, lung and liver, without knowing understanding the molecular mechanism. The present study hypothesized that treatment with EIso can affect the physiological processes of human lung bronchial epithelial cells (16HBE) prior to I/R. To test this hypothesis, the present study first constructed stable p53 knockdown and synthesis of cytochrome c oxidase (SCO)2 knockdown 16HBE cells. The above cells were subsequently treated with EIso at a concentration of 0.1 and 0.2% for 24 h. The relevant concentration of fat emulsion was used as a negative control. The expression levels of p53, p21, SCO1, SCO2 and Tp53‑induced glycolysis and apoptosis regulator (TIGAR) were detected by reverse transcription‑quantitative polymerase chain reaction and western blotting. Subsequently, the cell proliferation, respiration and glycolysis were investigated. The results revealed that EIso treatment significantly decreased the transcription of TIGAR, SCO1 and SCO2, and increased the transcription of p21, which are all p53 target genes, in a p53-independent manner. The cell cycle was inhibited by arresting cells at the G0/G1 phase. Respiration was reduced, which caused a decrease in oxygen consumption and the accumulation of lactate and reactive oxygen species. Taken together, EIso treatment inhibited the proliferation and respiration, and promoted glycolysis in 16HBE cells. This regulatory pathway may represent a protective mechanism of EIso treatment by inhibiting cell growth and decreasing the oxygen consumption from I/R.

Cardioprotection from emulsified isoflurane postconditioning is lost in rats with streptozotocin-induced diabetes due to the impairment of Brg1/Nrf2/STAT3 signalling

IsoPostC confers cardioprotection against myocardial IRI in non-diabetic rats but loses its effectiveness in diabetes, which may be mainly due to the impairment/reduction of Brg1/Nrf2/STAT3.

Induction of m2 polarization in primary culture liver macrophages from rats with acute pancreatitis

Background and Aims

Systemic inflammatory response syndrome (SIRS), a major process of severe acute pancreatitis (SAP), usually occurs after various activated proinflammatory cytokines, which are produced by macrophages such as liver macrophages. Macrophages can secrete not only proinflammatory mediators but also inhibitory inflammatory cytokines such as IL-10, leading to two different functional states defined as “polarization”. The main purpose of this study was to demonstrate the polarization of liver macrophages during severe acute pancreatitis and to explore whether the polarization of these activated Liver macrophages could be reversed in vitro.

Methods

Liver macrophages were isolated from rats with acute pancreatitis. These primary culture macrophages were treated with IL-4 or regulatory T cells in vitro to reverse their polarization and was evaluated by measuring M1/M2 marker expression using real time PCR and immunofluorescence staining.

Results

Acute pancreatitis was induced successfully by intra-pancreatic ductal injection of 5% sodium taurocholate. The liver macrophages demonstrated M1 polarization from 4 h to 16 h after the onset of acute pancreatitis. However, after IL-4 or Treg treatment, the polarization of the liver macrophages was reversed as indicated by increased expression of M2 markers and reduced expression of M1 markers. Furthermore, the effect of Treg on modulating macrophage polarization was slightly better than that of IL-4 in vitro.

Conclusion

Liver macrophages, a pivotal cell type in the pathogenesis of SAP, become M1 polarized during pancreatic inflammation. Treatment of these cells with IL-4 and Treg can reverse this activation in vitro. This method of altering macrophage polarization could be a prospective therapy for SAP.