liver-cold-storage-transplantation-cold-adaptive-daurian-ground

Liver Cold Storage and Transplantation in the Cold-Adaptive Daurian Ground Squirrels

In liver transplantation, the functional recovery of donor grafts following extended cold storage is a major challenge. The same obstacle applies to ...

post-liver-transplantation-management-specimen-collection-daurian

Post-Liver Transplantation Management and Specimen Collection in Daurian Ground Squirrels for Single-Cell RNA Sequencing

Graft functional recovery and graft-host immunocompatibility represent major prognostic concerns following liver transplantation. Critically, conventional ...

 Hibernating thirteen-lined ground squirrels (GS; ) are naturally adapted to prolonged periods of ultraprofound hypothermia (body temperature < 5 ºC) during torpor, and drastic oscillations of body temperature and ischemia/reperfusion-like stress during their short euthermic interbout arousals. Thus, their superior adaptability may hold tremendous promise for the advancement of donor organ cold preservation and subsequent organ transplantation. However, bridging hibernation research and translational medicine has been impeded by a dearth of  research tools, till the recent establishment of the GS induced pluripotent stem cells (iPSCs). In this study, we reported the generation of functional hepatocyte-like cells (HLCs) from GS iPSCs. As temperature and oxygen supply affect cellular metabolism, we hypothesized that the GS HLCs can metabolically counter drastic temperature and oxygen supply changes. Differentially regulated metabolites can be evaluated and included into the preservation solution to mitigate temperature and ischemia/reperfusion-associated damage to donor livers.  A protocol has been developed to produce GS iPSCs-derived HLCs. Comparative metabolomic analysis on GS HLCs and human donor liver samples revealed changes in metabolites caused by cold storage and rewarming. Human embryonic stem cell (ESC)-derived HLCs and  cold preservation and reperfusion of isolated rat livers were used to assess candidate metabolites that may have protective effects against preservation-related injuries.  GS iPSCs were efficiently differentiated into expandable, cryopreservation-compatible and functional HLCs. Metabolomic analysis unveiled distinct changes of mitochondrial metabolites between GS and human cells following cold storage and rewarming. GS and human HLC-based experiments indicated that the metabolism of 5-aminolevulinate (5-ALA) is key to restricting free radical production during rewarming. Survival of human HLCs was significantly increased following cold exposure and rewarming, as supplemented 5-ALA enhanced Complex III activity and improved mitochondrial respiration. Further, 5-ALA mitigated damage in rat livers following 48-h cold preservation and  reperfusion. Metabolomic and transcriptomic analyses revealed that supplemented 5-ALA promoted both anabolic and catabolic activities while alleviating cell death, inflammation, hypoxia and other stress responses in isolated perfused rat livers.  In the liver, rewarming from ultraprofound hypothermia imposes complex metabolic challenges and stresses on the mitochondria. Metabolites such as 5-ALA can help alleviate mitochondrial stress. Supplementing 5-ALA to the liver preservation solution can substantially improve the functional recovery of rat livers following prolonged cold preservation, rewarming and reperfusion.

5-Aminolevulinate improves metabolic recovery and cell survival of the liver following cold preservation.

Recent studies have proved that tenofovir disoproxil fumarate (TDF) is associated with a lower risk of hepatocellular carcinoma (HCC) occurrence in chronic hepatitis B (CHB) patients and HCC recurrence in patients who underwent hepatectomy when compared to ETV. However, it is unclear whether TDF and ETV treatment, which are both recommended as first-line antiviral agents to prevent the hepatitis B (HBV) recurrence after liver transplantation (LT), are associated with equivalent prognosis. We aim to compare risk of HCC recurrence and survival of patients recieving TDF or ETV after LT for HBV-related HCC.

Tenofovir versus entecavir on decreasing risk of HBV-related hepatocellular carcinoma recurrence after liver transplantation.

Inadequate remnant volume and regenerative ability of the liver pose life-threatening risks to patients after partial liver transplantation (PLT) or partial hepatectomy (PHx), while few clinical treatments focus on safely accelerating regeneration. Recently, we discovered that supplementing 5-aminolevulinate (5-ALA) improves liver cold adaptation and functional recovery, leading us to uncover a correlation between 5-ALA metabolic activities and post-PLT recovery. In a mouse 2/3 PHx model, 5-ALA supplements enhanced liver regeneration, promoting infiltration and polarization of anti-inflammatory macrophages via P53 signaling. Intriguingly, chemokine receptor CX3CR1 functions to counterbalance these effects. Genetic ablation or pharmacological inhibition of CX3CR1 (AZD8797; phase II trial candidate) augmented the macrophagic production of insulin-like growth factor 1 (IGF-1) and subsequent hepatocyte growth factor (HGF) production by hepatic stellate cells. Thus, short-term treatments with both 5-ALA and AZD8797 demonstrated pro-regeneration outcomes superior to 5-ALA-only treatments in mice after PHx. Overall, our findings may inspire safe and effective strategies to better treat PLT and PHx patients.

Synergy of 5-aminolevulinate supplement and CX3CR1 suppression promotes liver regeneration via elevated IGF-1 signaling.

Cold and ischemia/reperfusion (IR)-associated injuries are seemingly inevitable during liver transplantation and hepatectomy. Because Syrian hamsters demonstrate intrinsic tolerance to transplantation-like stimuli, cross-species comparative metabolomic analyses were conducted with hamster, rat, and donor liver samples to seek hepatic cold and IR-adaptive mechanisms. Lower hepatic phosphocholine contents were found in recipients with early graft-dysfunction and with virus-caused cirrhosis or high model for end-stage liver disease scores (≥30). Choline/phosphocholine deficiency in cultured human THLE-2 hepatocytes and animal models weakened hepatocellular cold tolerance and recovery of glutathione and ATP production, which was rescued by phosphocholine supplements. Among the biological processes impacted by choline/phosphocholine deficiency, 3 lipid-related metabolic processes were downregulated, whereas phosphocholine elevated the expression of genes in methylation processes. Consistently, in THLE-2, phosphocholine enhanced the overall RNA mA methylation, among which the transcript stability of fatty acid desaturase 6 (FADS6) was improved. FADS6 functioned as a key phosphocholine effector in the production of polyunsaturated fatty acids, which may facilitate the hepatocellular recovery of energy and redox homeostasis. Thus, our study reveals the choline-phosphocholine metabolism and its downstream FADS6 functions in hepatic adaptation to cold and IR, which may inspire new strategies to monitor donor liver quality and improve recipient recovery from the liver transplantation process.

ArticleTotal : 2	Year
Publication title	2025
Publication title	2025

Article	Year
5-Aminolevulinate improves metabolic recovery and cell survival of the liver following cold preservation. Theranostics\| PubMed ID: 35401816	2022
Tenofovir versus entecavir on decreasing risk of HBV-related hepatocellular carcinoma recurrence after liver transplantation. Infectious agents and cancer\| PubMed ID: 36650583	2023
Synergy of 5-aminolevulinate supplement and CX3CR1 suppression promotes liver regeneration via elevated IGF-1 signaling. Cell reports\| PubMed ID: 37578861	2023
Cross-species metabolomic profiling reveals phosphocholine-mediated liver protection from cold and ischemia/reperfusion. American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons\| PubMed ID: 38878865	2024

Haobin Sun

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