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Background & Aims: Liver regeneration is a repair process in which metabolic reprogramming of parenchymal and inflammatory cells plays a major role. Monoacylglycerol lipase (MAGL) is an ubiquitous enzyme at the crossroad between lipid metabolism and inflammation. It converts monoacylglycerols into free fatty acids and metabolises 2-arachidonoylglycerol into arachidonic acid, being thus the major source of pro-inflammatory prostaglandins in the liver. In this study, we investigated the role of MAGL in liver regeneration., Methods: Hepatocyte proliferation was studied in vitro in hepatoma cell lines and ex vivo in precision-cut human liver slices. Liver regeneration was investigated in mice treated with a pharmacological MAGL inhibitor, MJN110, as well as in animals globally invalidated for MAGL (MAGL -/- ) and specifically invalidated in hepatocytes (MAGL Hep-/- ) or myeloid cells (MAGL Mye-/- ). Two models of liver regeneration were used: acute toxic carbon tetrachloride injection and two-thirds partial hepatectomy. MAGL Mye-/- liver macrophages profiling was analysed by RNA sequencing. A rescue experiment was performed by in vivo administration of interferon receptor antibody in MAGL Mye-/- mice., Results: Precision-cut human liver slices from patients with chronic liver disease and human hepatocyte cell lines exposed to MJN110 showed reduced hepatocyte proliferation. Mice with global invalidation or mice treated with MJN110 showed blunted liver regeneration. Moreover, mice with specific deletion of MAGL in either hepatocytes or myeloid cells displayed delayed liver regeneration. Mechanistically, MAGL Hep-/- mice showed reduced liver eicosanoid production, in particular prostaglandin E 2 that negatively impacts on hepatocyte proliferation. MAGL inhibition in macrophages resulted in the induction of the type I interferon pathway. Importantly, neutralising the type I interferon pathway restored liver regeneration of MAGL Mye-/- mice., Conclusions: Our data demonstrate that MAGL promotes liver regeneration by hepatocyte and macrophage reprogramming., Impact and Implications: By using human liver samples and mouse models of global or specific cell type invalidation, we show that the monoacylglycerol pathway plays an essential role in liver regeneration. We unveil the mechanisms by which MAGL expressed in both hepatocytes and macrophages impacts the liver regeneration process, via eicosanoid production by hepatocytes and the modulation of the macrophage interferon pathway profile that restrains hepatocyte proliferation., (© 2023 The Author(s).)

Microglia, the resident phagocytes of the central nervous system and one of the key modulators of the innate immune system, have been shown to play a major role in brain insults. Upon activation in response to neuroinflammation, microglia promote the release of inflammatory mediators as well as promote phagocytosis. Plasma prekallikrein (PKall) has been recently implicated as a mediator of neuroinflammation; nevertheless, its role in mediating microglial activation has not been investigated yet. In the current study, we evaluate the mechanisms through which PKall contributes to microglial activation and release of inflammatory cytokines assessing PKall-related receptors and their dynamics. Murine N9-microglial cells were exposed to PKall (2.5 ng/ml), lipopolysaccharide (100 ng/ml), bradykinin (BK, 0.1 μM), and neuronal cell debris (16.5 μg protein/ml). Gene expression of bradykinin 2 receptor (B 2 KR), protease-activated receptor 2 (PAR-2), along with cytokines and fibrotic mediators were studied. Bioinformatic analysis was conducted to correlate altered protein changes with microglial activation. To assess receptor dynamics, HOE-140 (1 μM) and GB-83 (2 μM) were used to antagonize the B 2 KR and PAR-2 receptors, respectively. Also, the role of autophagy in modulating microglial response was evaluated. Data from our work indicate that PKall, LPS, BK, and neuronal cell debris resulted in the activation of microglia and enhanced expression/secretion of inflammatory mediators. Elevated increase in inflammatory mediators was attenuated in the presence of HOE-140 and GB-83, implicating the engagement of these receptors in the activation process coupled with an increase in the expression of B 2 KR and PAR-2. Finally, the inhibition of autophagy significantly enhanced the release of the cytokine IL-6 which were validated via bioinformatics analysis demonstrating the role of PKall in systematic and brain inflammatory processes. Taken together, we demonstrated that PKall can modulate microglial activation via the engagement of PAR-2 and B 2 KR where PKall acts as a neuromodulator of inflammatory processes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Jaffa, Jaffa, Moussa, Ahmed, Karam, Aldeen, Al Sayegh, El-Achkar, Nasrallah, Yehya, Habib, Ziyadeh, Eid, Kobeissy and Jaffa.)

The occurrence and persistence of hepatic injury which arises from cell death and inflammation result in liver disease. The processes that lead to liver injury progression and resolution are still not fully delineated. The plasma kallikrein-kinin system (PKKS) has been shown to play diverse functions in coagulation, tissue injury, and inflammation, but its role in liver injury has not been defined yet. In this study, we have characterized the role of the PKKS at various stages of liver injury in mice, as well as the direct effects of plasma kallikrein on human hepatocellular carcinoma cell line (HepG2). Histological, immunohistochemical, and gene expression analyses were utilized to assess cell injury on inflammatory and fibrotic factors. Acute liver injury triggered by carbon tetrachloride (CCl 4 ) injection resulted in significant upregulation of the plasma kallikrein gene (Klkb1) and was highly associated with the high mobility group box 1 gene, the marker of cell death ( r = 0.75, p < 0.0005, n = 7). In addition, increased protein expression of plasma kallikrein was observed as clusters around necrotic areas. Plasma kallikrein treatment significantly increased the proliferation of CCl 4 -induced HepG2 cells and induced a significant increase in the gene expression of the thrombin receptor (protease activated receptor-1), interleukin 1 beta, and lectin-galactose binding soluble 3 (galectin-3) ( p < 0.05, n = 4). Temporal variations in the stages of liver fibrosis were associated with an increase in the mRNA levels of bradykinin receptors: beta 1 and 2 genes ( p < 0.05; n = 3-10). In conclusion, these findings indicate that plasma kallikrein may play diverse roles in liver injury, inflammation, and fibrosis, and suggest that plasma kallikrein may be a target for intervention in the states of liver injury., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Ahmed, Jaffa, Moussa, Hatem, El-Achkar, Al Sayegh, Karam, Hamade, Habib and Jaffa.)

Objective: The purpose of this study was to describe typical anesthesia practices for children with obstructive sleep apnea (OSA)., Study Design: Online survey., Method: A sample of pediatric anesthesiologists received the survey by email., Results: 110 respondents were included. 46.4% worked in a free-standing children's hospital and 32.7% worked in a children's facility within a general hospital. 73.6% taught residents. 44.4% saw at least one child with OSA per week, 25.5% saw them daily. On a 100-mm visual analog scale, respondents rated their comfort with managing these children as 84.94 (SD 17.59). For children with severe OSA, 53.6% gave oral midazolam preoperatively, but 24.5% typically withheld premedication and had the parent present for induction. 68.2% would typically use nitrous oxide for inhalational induction. 68.2% used fentanyl intraoperatively, while 20.0% used morphine. 61.5% reduced their intraop narcotic dose for children with OSA. 98.2% used intraoperative dexamethasone, 58.2% used 0.5 mg/kg for the dose. 98.2% used ondansetron, 62.7% used IV acetaminophen, and 8.2% used IV NSAIDs. 83.6% extubated awake. 27.3% of respondents stated that their institution had standardized guidelines for perioperative management of children with OSA undergoing adenotonsillectomy. People who worked in children's hospitals, who had >10 years of experience, or who saw children with OSA frequently were significantly more comfortable dealing with children with OSA ( P < 0.05)., Conclusion: Apart from using intraoperative dexamethasone and ondansetron, management varied. These children would likely benefit from best practices perioperative management guidelines.

Background: Radiotherapy remains one of the cornerstones to improve the outcome of colorectal cancer (CRC) patients. Radiotherapy of the CRC not only help to destroy cancer cells but also remodel the tumour microenvironment by enhancing tumour-specific tropism of bone marrow-derived mesenchymal stromal cell (BM-MSC) from the peripheral circulation. However, the role of local MSCs and recruited BM-MSC under radiation were not well defined. Indeed, the functions of BM-MSC without irradiation intervention remained controversial in tumour progression: BM-MSC was previously shown to modulate the immune function of major immune cells, resulting in an impaired immunological sensitivity and to induce an increased risk of tumour recurrence. In contrast, it could also secrete various cytokines and possess anticancer effect., Methods: Three co-cultivation modules, 3D culture modules, and cancer organoids were established. The induction of cytokines secretion in hBM-MSCs after irradiation was analysed by ELISA array and flow cytometry. AutoMac separator was used to separate hBM-MSC and CRC automatically. Cells from the co-cultured group and the control group were then irradiated by UV-C lamp and X-ray. Proliferation assay and viability assay were performed., Results: In this study, we show that BM-MSCs can induce the EMT progression of CRC cells in vitro. When irradiated with low doses of ultraviolet radiation and X-rays, BM-MSCs show an anti-tumour effect by secreting certain cytokine (TNF-α, IFN-γ) that lead to the inhibition of proliferation and induction of apoptosis of CRC cells. This was further verified in a 3D culture model of a CRC cell in vitro. Furthermore, irradiation on the co-culture system induced the cleavage of caspase3, and attenuated the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/AKT and extracellular signal-regulated kinase in cancer cells. The signal pathways above might contribute to the cancer cell death., Conclusions: Taken together, we show that BM-MSC can potentially promote the effect of radiotherapy in CRC.

Background: The purpose of this study is to investigate the prognostic value of pre-resection serum carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 after resection of ampullary cancer (AC) in consideration of intestinal (IT) and pancreatobiliary (PT) subtypes., Methods: Overall survival (OS) analysis of patients undergoing curative resection of ampullary cancer., Results: Elevated preoperative CEA (P = 0.013) and CA 19-9 levels (P = 0.030) were significant prognostic factors. Subgroup analysis, however, showed both markers having prognostic value only for the IT subgroup. Pre-resection CEA within normal range identified a subgroup of IT patients with an excellent median survival of 145 months. Compared to other AC patients, this low-risk IT CEA - subpopulation was characterized by less frequent advanced pT stages (pT3/pT4, 41 vs. 62%; P = 0.047) and lymph node involvement (pN+, 30 vs. 65%; P = 0.001). OS of this subgroup was significantly better compared to other AC patients (145 vs. 25 months; HR = 3.8; P < 0.001). By multivariate survival analysis, the patient age, the PT subtype, and an elevated pre-resection serum CEA value were identified as independent prognostic variables., Conclusions: In AC, the histomorphologic subclassification is highly relevant regarding the prognostic value of preoperative serum CEA and CA 19-9. IT-patients with normal preoperative CEA represent a favorable subgroup with excellent long-term survival.