International multicenter study of ultralow graft-to-recipient weight ratio grafts in adult living donor liver transplantation.

Decreasing the graft size in living donor liver transplantation (LDLT) increases the risk of early allograft dysfunction. Graft-to-recipient weight ratio (GRWR) of 0.8 is considered the threshold. There is evidence that smaller volume grafts may also provide equally good outcomes, the cut-off of which remains unknown. In this retrospective multicenter study, 92 adult LDLTs with a final GRWR ≤0.6 performed at 12 international liver transplant centers over a 3-year period were included. Perioperative data including preoperative status, portal flow hemodynamics (PFH) and portal flow modulation, development of small for size syndrome (SFSS), morbidity, and mortality was collated and analyzed. Thirty-two (36.7%) patients developed SFSS and this was associated with increased 30-day, 90-day, and 1-year mortality. The preoperative model for end-stage liver disease and inpatient status were independent predictors for SFSS (P < .05). Pre-liver transplant renal dysfunction was an independent predictor of survival (hazard ratio 3.1; 95% confidence intervals 1.1, 8.9, P = .035). PFH or portal flow modulation were not predictive of SFSS or survival. We report the largest ever multicenter study of LDLT outcomes using ultralow GRWR grafts and for the first time validate the International Liver Transplantation Society-International Living donor liver transplantation study group-Liver Transplantation Society of India consensus definition and grading of SFSS. Preoperative recipient condition rather than GRWR and PFH were independent predictors of SFSS. Algorithms to predict SFSS and LT outcomes should incorporate recipient factors along with GRWR.

Domino hepatocyte transplantation using explanted human livers with metabolic defects attenuates D-GalN/LPS-induced acute liver failure.

BACKGROUND: Explanted livers from patients with inherited metabolic liver diseases possess the potential to be a cell source of good-quality hepatocytes for hepatocyte transplantation (HT). This study evaluated the therapeutic effects of domino HT using hepatocytes isolated from explanted human livers for acute liver failure (ALF). METHODS: Isolated hepatocytes were evaluated for viability and function and then transplanted into D-galactosamine/lipopolysaccharide-induced ALF mice via splenic injection. The survival rate was analyzed by the Kaplan-Meier method and log-rank test. Liver function was evaluated by serum biochemical parameters, and inflammatory cytokine levels were measured by ELISA. The pathological changes in the liver tissues were assessed by hematoxylin-eosin staining. Hepatocyte apoptosis was investigated by TUNEL, and hepatocyte apoptosis-related proteins were detected by western blot. The localization of human hepatocytes in the injured mouse livers was detected by immunohistochemical analyses. RESULTS: Hepatocytes were successfully isolated from explanted livers of 10 pediatric patients with various liver-based metabolic disorders, with an average viability of 85.3% ± 13.0% and average yield of 9.2 × 106 ± 3.4 × 106 cells/g. Isolated hepatocytes had an excellent ability to secret albumin, produce urea, uptake indocyanine green, storage glycogen, and express alpha 1 antitrypsin, albumin, cytokeratin 18, and CYP3A4. Domino HT significantly reduced mortality, decreased serum levels of alanine aminotransferase and aspartate aminotransferase, and improved the pathological damage. Moreover, transplanted hepatocytes inhibited interleukin-6 and tumor necrosis factor-α levels. Domino HT also ameliorates hepatocyte apoptosis, as evidenced by decreased TUNEL positive cells. Positive staining for human albumin suggested the localization of human hepatocytes in ALF mice livers. CONCLUSION: Explanted livers from patients with inheritable metabolic disorders can serve as a viable cell source for cell-based therapies. Domino HT using hepatocytes with certain metabolic defects has the potential to be a novel therapeutic strategy for ALF.

Elevated effluent potassium concentrations predict the development of postreperfusion hyperkalemia in deceased liver transplantation: a retrospective cohort study.

BACKGROUND: Postreperfusion hyperkalemia (PRHK) has garnered increasing attention in regard to deceased liver transplantation (LT), especially for LT using the expanded criteria donor grafts. However, the impact of the effluent potassium (eK+) concentration on PRHK has been largely overlooked. We evaluated whether elevated eK+ concentrations are associated with PRHK in deceased LT. METHODS: In this single-institution, retrospective cohort study, we included all adults who underwent deceased LT with intraoperative eK+ concentration monitoring between November 2016 and December 2018. The eK+ concentrations were obtained from the effluent samples collected following a standard portal vein flush. PRHK was defined as any serum potassium (sK+) level of > 5.5 mmol/L following reperfusion. Logistic regression was performed to identify predictors for PRHK, and linear regression was used to examine predictors of the maximum percentage increase in the sK+ level following reperfusion. RESULTS: Of the 86 patients who met the inclusion criteria, 54 (62.8%) developed PRHK. Independent predictors for PRHK included greater graft weight (OR 1.283 [95% CI 1.029-1.599] per 100 g, P = 0.027), an elevated eK+ concentration (OR 1.291 [95% CI 1.068-1.561] per mol/L, P = 0.008), and a higher sK+ level before reperfusion (OR 4.459 [95% CI 1.543-12.884] per mol/L, P = 0.006). An eK+ concentration of more than 6.9 mmol/L had a sensitivity of 59.26% and a specificity of 78.12% for predicting PRHK (area under the receiver operating characteristic curve, 0.694). Multiple linear regression analyses indicated that the eK+ and sK+ levels before reperfusion were significant predictors of the maximum percentage increase in the sK+ level following reperfusion. In addition, PRHK was associated with an increased risk of postreperfusion significant arrhythmias, severe postreperfusion syndrome, and postoperative early allograft dysfunction. CONCLUSIONS: This study shows that the eK+ concentration could predict the risk of PRHK in deceased LT. Further prospective studies are warranted to clarify these associations.

Marginal parental donors for pediatric living donor liver transplantation.

PURPOSE OF REVIEW: Living donor liver transplantation (LT) has been increasingly recognized as an effective treatment modality with excellent patient survival. Indications for LT have evolved not only for cholestatic liver disease, but also metabolic liver diseases. Living donor selection, particularly for pediatric inherited disease, is essential to prevent morbidity, both in the donor and recipient. RECENT FINDINGS: Based on 30 years of experience in pediatric living donor LT in Japan, we could identify marginal parental living donors who have potential risks following LT, including heterozygous mothers with ornithine transcarbamylase deficiency, heterozygous protein C deficiency, heterozygous hypercholesterolemia, heterozygous protoporphyria, asymptomatic parental donors with paucity of intrahepatic bile duct, and human leukocyte antigen-homozygous parental donors. SUMMARY: Although these situations seem rare due to infrequency of the condition, careful living donor evaluation is required to optimize the outcomes for pediatric recipients. In the setting of an appropriate selection of a living donor, we should avoid any additional hazards, given that the procedure itself has risks for a healthy individual.

Perioperative Management and Clinical Outcomes of Liver Transplantation for Children with Homozygous Familial Hypercholesterolemia.

Background and Objectives: Liver transplantation (LT) has been accepted as a life-saving option as a last resort for children with homozygous familial hypercholesterolemia (HoFH). Perioperative management of LT for HoFH poses extra challenges for clinicians largely due to premature atherosclerotic cardiovascular diseases (ASCVDs). We aimed to analyze our data of pediatric LT recipients with HoFH, with special attention paid to perioperative management and clinical outcomes. Materials and Methods: After obtaining approval from the local ethics committee, the clinical data of pediatric patients with HoFH who underwent LT at our institution between January 2014 and February 2021 were retrospectively studied. Results: Six pediatric LT recipients with HoFH were included in the analysis. Although ASCVDs were common before LT, all children with HoFH survived the perioperative period without in-hospital mortality. However, one patient experienced acute myocardial infarction two months following LT and was successfully treated with medical interventions. Post-LT metabolic improvement was shown by declines in serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels in the early post-LT period (for TC: 14.7 ± 3.2 mmol/L vs. 5.5 ± 1.8 mmol/L, p < 0.001; for LDL-C: 10.6 ± 2.2 mmol/L vs. 3.6 ± 1.2 mmol/L, p < 0.001, respectively) and at the last follow-up (for TC: 14.7 ± 3.2 mmol/L vs. 4.5 ± 0.9 mmol/L, p = 0.001; for LDL-C: 10.6 ± 2.2 mmol/L vs. 2.8 ± 0.6 mmol/L, p = 0.001, respectively). Dietary restrictions could be lifted after LT. However, three patients required restarting lipid-lowering therapy after LT due to suboptimal LDL-C levels and progression of ASCVDs. Conclusions: Our data suggest that LT can be a safe and feasible therapeutic option for well-selected patients with HoFH, offering relaxed dietary restrictions and remarkable reductions in LDL-C levels. However, concerns remain regarding progression of ASCVDs after LT.

Early transjugular intrahepatic portosystemic shunt for acute variceal bleeding: a systematic review and meta-analysis.

OBJECTIVES: The alleged benefit of early placement of transjugular intrahepatic portosystemic shunt (TIPS) in patients with cirrhosis and acute variceal bleeding (AVB) remains controversial. This meta-analysis was conducted to evaluate the therapeutic effect of early TIPS on cirrhotic patients with AVB. METHODS: MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases were searched for relevant literatures. Data from included studies were extracted, and random-effects meta-analyses were performed. RESULTS: Three randomized control trials and six observational studies involving 2878 participants were included. Compared with those undergoing standard treatment, patients undergoing early TIPS had a significantly lower all-cause mortality (RR, 0.64; 95% CI, 0.52-0.79). Furthermore, early TIPS was associated with a significantly reduced incidence of failure to control bleeding (RR, 0.15; 95% CI, 0.07-0.29) and rebleeding (RR, 0.40; 95% CI, 0.23-0.71), without increasing the risk of hepatic encephalopathy (RR, 1.13; 95% CI, 0.92-1.38). In a stratification analysis based on Child-Pugh classification, the survival benefit was observed in Child-Pugh B patients with active bleeding (RR, 0.53; 95% CI, 0.31-0.93) and Child-Pugh C patients (RR 0.55, 95% CI, 0.37-0.82), but not in low-risk patients (Child-Pugh A and Child-Pugh B without active bleeding) (RR, 0.93; 95% CI, 0.55-1.57). CONCLUSION: Early TIPS is a feasible therapeutic option for cirrhotic patients with AVB, especially benefiting high-risk patients in terms of improved survival. Given the current low utilization rate in clinical practice, this study favors the placement of early TIPS in a wider range of patients with cirrhosis and AVB, especially high-risk patients. KEY POINTS: • Early TIPS is associated with improved survival in high-risk patients (Child-Pugh B plus active bleeding at endoscopy or Child-Pugh C 10-13) with cirrhosis and acute variceal bleeding. • Current utilization rate of early TIPS is low in clinical practice.

Post-transplant lymphoproliferative disorder after paediatric liver transplantation.

OBJECTIVE: The purpose of this study was to analyse the clinical and pathological characteristics, treatments and outcomes of post-transplant lymphoproliferative disorder (PTLD) in paediatric liver transplant recipients. METHOD: A retrospective analysis of records from nine paediatric liver transplant recipients with PTLD who were treated at our Liver Transplant Center over the period from June 2013 to August 2018. RESULT: Of these nine patients, seven received liver transplantation in our centre and the remaining two patients at other hospitals. The overall incidence of PTLD in paediatric liver transplant recipients in our centre was 1.4% (7/485). The median onset of PTLD after liver transplantation was 11 months. Three cases were classified as infectious mononucleosis PTLD, one case was plasmacytic hyperplasia PTLD, one case was polymorphic PTLD and two cases were Burkitt lymphoma. One case showed diffuse large B-cell lymphoma and one was classical Hodgkin lymphoma-like PTLD. These patients presented with different clinical manifestations including fever, anaemia, diarrhoea, hypoproteinaemia, enlargement of lymph nodes, hepatosplenomegaly, jaundice, bowel obstruction and even intestinal perforation. Nine patients were positive for EBV-DNA in serum. After diagnosis, immunosuppressants were reduced or discontinued in all cases. Eight patients received anti-CD20 monoclonal antibody (Rituximab) therapy, four cases were treated with a combination of chemotherapy (R-CHOP, ABVD, COPP/ABV) and one case was combined with radiotherapy. Two cases received surgical treatment due to bowel obstruction. Eight of these patients achieved a complete remission and remained healthy when assessed at the time of final follow-up. One patient died as a result of PTLD progression. CONCLUSION: PTLD is one of the most serious and fatal complications after liver transplantation. The definitive diagnosis requires histopathology. Treatment varies and basically includes immunosuppression reduction, anti-CD20 antibody, surgery, radiotherapy and chemotherapy.

Risk factors for portal vein stenosis in pediatric liver transplantation.

OBJECTIVE: To analyze the incidence and risk factors of portal vein stenosis (PVS) in pediatric liver transplantation (LT). METHODS: This retrospective analysis of 396 cases of pediatric LT (patients aged ≤ 14 years old) was conducted at the Liver Transplantation Center of Beijing Friendship Hospital (China) from June 2013 to December 2017. We collected relevant data and calculated the incidence. We analyzed a total of 23 risk factors for PVS children during the perioperative period. RESULTS: The incidence of PVS in pediatric LT was 6.6%. The following were identified as risk factors for PVS in pediatric LT: Preoperative portal hypertension was complicated, weight (≤7 kg), recipients of portal vein diameter ≤4 mm, GRWR (≥3.5%), the use of cold preservation vein grafts, anastomosis in the region of superior mesenteric vein and splenic vein and reverse blood flow in the portal vein shown in preoperative ultrasound examination. Recipients of portal vein diameter ≤4 mm and the use cold preservation grafts were independent risks factors for PVS in pediatric LT. CONCLUSION: For recipients with the risk factors identified in this study, we strongly recommend a strict follow-up and the provision of suitable interventions when indicated.

TINCR facilitates non-small cell lung cancer progression through BRAF-activated MAPK pathway.

Long non-coding RNAs are critically involved in oncogenesis in various cancer types. Here we reported a novel lncRNA signature correlated with progression of non-small cell lung cancer (NSCLC). In particular, we identified elevated expression of terminal differentiation-induced noncoding RNA (TINCR) in human NSCLC samples, which were associated with enhanced migration, viability in NSCLC cells in vitro. Higher TINCR level was also correlated with poor survival. Furthermore, TINCR increased xenograft tumor growth in vivo mouse models. Mechanistic study demonstrated that TINCR can interact with BRAF to facilitate its kinase activity, thereby leading to activation of oncogenic mitogen-activated protein kinase (MAPK) pathway. These results suggested that TINCR upregulation may signal through the MAPK pathway to promote NSCLC tumorigenesis. Therefore, TINCR may serve as a potential prognostic marker and therapeutic target for NSCLC patients.

Cisplatin and photodynamic therapy exert synergistic inhibitory effects on small-cell lung cancer cell viability and xenograft tumor growth.

Lung cancer is the leading cause of cancer death worldwide. Small-cell lung cancer (SCLC) is an aggressive type of lung cancer that shows an overall 5-year survival rate below 10%. Although chemotherapy using cisplatin has been proven effective in SCLC treatment, conventional dose of cisplatin causes adverse side effects. Photodynamic therapy, a form of non-ionizing radiation therapy, is increasingly used alone or in combination with other therapeutics in cancer treatment. Herein, we aimed to address whether low dose cisplatin combination with PDT can effectively induce SCLC cell death by using in vitro cultured human SCLC NCI-H446 cells and in vivo tumor xenograft model. We found that both cisplatin and PDT showed dose-dependent cytotoxic effects in NCI-H446 cells. Importantly, co-treatment with low dose cisplatin (1 µM) and PDT (1.25 J/cm2) synergistically inhibited cell viability and cell migration. We further showed that the combined therapy induced a higher level of intracellular ROS in cultured NCI-H446 cells. Moreover, the synergistic effect by cisplatin and PDT was recapitulated in tumor xenograft as revealed by a more robust increase in the staining of TUNEL (a marker of cell death) and decrease in tumor volume. Taken together, our findings suggest that low dose cisplatin combination with PDT can be an effective therapeutic modality in the treatment of SCLC patients.

Protective role of normothermic machine perfusion during reduced-size liver transplantation in pigs.

The purpose of this study is to explore whether normothermic machine perfusion (NMP) preservation is superior to cold preservation during reduced-size liver transplantation (RSLT) in pigs. Twenty-four healthy Ba-Ma mini pigs were used (aged >13 months; weight 25-35 kg; regardless of sex). The animals were randomized into 2 groups. In group A (NMP), donor livers were harvested without warm ischemia time and heartbeats and then were connected to the NMP system to reduce the livers' size under the normothermic condition. In group B (University of Wisconsin [UW] solution), donor livers were harvested without warm ischemia time and heartbeats after being perfused by UW solution and were then preserved in 0°C-4°C UW solution to reduce the livers' size under cold conditions. After that, liver transplantation without venovenous bypass was performed. General RSLT information of the pigs from the 2 groups was recorded; the serological indices were measured; and routine pathological examination of liver tissue was observed. A significant difference was observed in the intraoperative bleeding between the 2 groups (P < 0.05), whereas no significant difference was found in the other indices (all P > 0.05). Significant differences of alanine aminotransferase levels, aspartate aminotransferase levels, and lactate dehydrogenase levels between the 2 groups were observed between postoperative days 3 and 5 (P < 0.05). Significant differences of lactic acid levels between the 2 groups were observed between postoperative days 2 and 5 (P < 0.05). Compared with the cold preservation group, the liver tissues of the NMP preservation group only rarely experienced liver cell necrosis and maintained integrities in the hepatic sinusoid spaces and endothelial cells. In conclusion, NMP preservation is superior to cold preservation during RSLT in pigs. Liver Transplantation 22 968-978 2016 AASLD.

Tacrolimus-related seizure after pediatric liver transplantation--a single-center experience.

To identify the risk factors for new-onset seizures after pediatric LT and to assess their clinical implications and long-term prognosis. The clinical and laboratory data of 27 consecutive children who underwent LT from January 2007 to December 2010 in our center were analyzed retrospectively. Patients were divided into seizures group and a non-seizures group. Pre-operative, intra-operative, and post-operative data were collected. Seizures occurred in four children, an incidence of 14.8%. All exhibited generalized tonic-clonic seizures within the first two wk after LT. Univariate analysis showed that the risk factors associated with seizures after pediatric LT included gender, pediatric end-stage liver disease score before surgery, Child-Pugh score before surgery, serum total bilirubin after surgery, and trough TAC level. Multivariate analysis showed that trough TAC level was the only independent risk factor associated with the seizures. All children who experienced seizures survived with good graft function and remained seizure-free without anti-epileptic drugs over a mean follow-up period of 33.7 ± 14.6 months. High trough TAC level was the predominant factor that contributed to seizures in the early post-operative period after pediatric LT. High PELD and Child-Pugh scores before LT and high post-operative serum Tbil may be contributory risk factors for TAC-related seizures.

Prognosis in liver transplantation recipients after hepatitis B virus recurrence.

BACKGROUND/AIMS: To analyze the data from hepatitis B virus (HBV) infected patients with HBV recurrence after orthotopic liver transplantation (OLT) to determine their prognosis and survival. METHODOLOGY: We retrospectively analyzed data from patients who experienced HBV recurrence following OLT at our center between January 2000 and September 2011. All patients were monitored until June 2012 or their death. RESULTS: The total number of cases of HBV recurrence after liver transplantation was 56. Of these cases, 21 had benign liver disease and 35 had hepatocellular carcinoma (HCC). The median follow-up time was 48.8 months (range: 5.0-138.1 months). The median time to recurrence following transplantation was 44.4 months (range: 0.3-116.3 months) and 12.2 months (range: 0.3-135.1 months) for patients with benign liver disease and HCC, respectively. Nine patients were diagnosed with HBV recurrence first (1.2-8.2 months prior to HCC recurrence), seven patients showed HCC recurrence first (0.4-27.1 months prior to HBV recurrence), and the remaining 5 patients had HBV and HCC recurrence at the same time. Correlation analysis demonstrated a strong correlation between HBV and HCC recurrence times. Of the 56 patients with HBV recurrence, 24 had died at the time of data cut off, and the main cause of death was HCC recurrence. In patients with malignant liver disease, the survival rates were 78.8%, 48.8%, and 40.1% at 1, 3, and 5 years, respectively, which were lower than those in patients with benign liver disease, which were 94.7%, 89.5%, and 77.5% at 1, 3, and 5 years, respectively, P=0.001. CONCLUSION: Patients with HBV recurrence and benign liver disease have a better prognosis than HCC patients. Treatment with the addition of adefovir and/or entecavir is necessary for patients with HBV recurrence. A correlation between HBV and HCC recurrence times was observed. Hepatitis B recurrence can be used as a warning signal for tumor recurrence.

Synchronous splenectomy and hepatectomy in patients with hepatocellular carcinoma, hypersplenism and liver cirrhosis.

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) mainly arises from underlying liver disease. Complicated liver cirrhosis and secondary hypersplenism are the most risk factors preventing surgical treatment of patients with HCC. The present study aimed at investigating the safety and long term outcome of patients with HCC and liver cirrhosis undergoing synchronous hepatectomy and splenectomy. METHODOLOGY: The clinical data of 306 cases of patients with HCC and liver cirrhosis undergoing curative hepatectomy were reviewed. 18 cases underwent synchronous hepatectomy and splenectomy. The rest 288 cases of HCC with hepatectomy only were compared in aspects of clinicopathological and surgical variables and surgical outcomes. RESULTS: Preoperative hemoglobin and platelet count were significantly lower in splenectomy than non-splenectomy group (p<0.01, respectively). Patients undergoing combined splenectomy and hepatectomy needed longer surgery time and hospital stay time, and transfused much more blood intraoperatively (p=0.07, 0.03, and 0.02), and also experienced more portal vein thrombosis (p<0.01). The level of hemoglobin and platelet increased after splenectomy and finally to normal level one month postoperatively. There was no statistical difference of overall and disease-free survival of patients in splenectomy and non-splenectomy groups (p>0.05). CONCLUSIONS: With strict selection, patients with HCC and hypersplenism could undergo combined splenectomy and hepatectomy safely.

[Effect of Kuanxiong aerosol on coronary heart disease angina patients: a multicenter randomized controlled clinical study].

OBJECTIVE: To evaluate the anginal attack-relieving efficacy and safety of Kuanxiong Aerosol (KA) in patients with coronary heart disease (CHD). METHODS: A total of 780 patients confirmatively diagnosed as CHD angina from November 2011 to December 2012 in 13 medical centers in the mainland area were assigned to 2 groups by blocked randomization, the treatment group (376 cases) and the control group (374 cases). When the angina attacked, patients in the treatment group received sublingual spray three times, 0.6 mL each time, while those in the control group sublingually dissolved Nitroglycerin Tablet (NT), 0.5 mg each tablet. The effective rate of angina relief, efficacy of electrocardiogram (ECG), and the incidence of adverse reactions were observed. RESULTS: The 3 min and 5 min remission rates of angina attack were 53.72% (202/376) and 94.41% (355/376) in the treatment group, and 47.86% (179/374) and 90.64% (339/374) in the control group. The 95% confidence interval (CI) of the difference between the 2 groups of 3 min and 5 min remission rates of angina attacks were [(-1.84%, 12.32%) and (-1.33%, 6.85%) respectively, P > 0.05]. The total improvement rates of ST-T changes in the treatment group and the control group after treatment were 74.07% and 73.13% respectively (P > 0.05). The adverse reaction rate was 9.31 (35/376 cases) in the treatment group and 22.46% (84/374 cases) in the control group (P < 0.01). CONCLUSION: KA was not inferior to NT in relieving anginal attacks and improving ischemic ECG changes, and had obviously less adverse reaction.

FLT3+ DC inhibits immune rejection via interaction with Treg in liver transplantation.

Fms-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase (RTK) primarily expressed in hematopoietic stem cells and dendritic cells (DCs). While FLT3 plays a critical role in the proliferation, development and maintenance of DCs, thus influencing immune responses under both normal and pathological conditions, there also exists some evidence that FLT3+DC may be involved with immune responses in liver transplantation (LT). In this study, results from single-cell sequencing data analysis revealed a clear relationship between FLT3+DCs and Regulatory T cells (Tregs) in liver tissue of LT recipients. In peripheral blood samples of LT patients, levels of FLT3+DCs were decreased post-LT-surgery, while Tregs were increased. In a LT mouse model, levels of FLT3+DCs in the liver and bone marrow exhibited an initial time-dependent decrease followed by an increase after LT surgery. Results as obtained with co-culture experiments using mature BMDCs and CD4+ T cells revealed fluctuations in Tregs in response to FLT3 inhibitors and the FLT3 ligand. These findings suggest that FLT3+DCs could emerge as a novel target for mitigating immune rejection in LT.

Myeloid-derived suppressor cells-induced exhaustion of CD8 + T-cell participates in rejection after liver transplantation.

Liver transplantation (LT) rejection remains the most pervasive problem associated with this procedure, while the mechanism involved is still complicated and undefined. One promising solution may involve the use of myeloid-derived suppressor cells (MDSC). However, the immunological mechanisms underlying the effects of MDSC after LT remain unclear. This study is meant to clarify the role MDSCs play after liver transplantation. In this study, we collected liver tissue and peripheral blood mononuclear cells (PBMC) from LT patients showing varying degrees of rejection, as well as liver and spleen tissue samples from mice LT models. These samples were then analyzed using flow cytometry, immunohistochemistry and multiple immunofluorescence. M-MDSCs and CD8 + T-cells extracted from C57/BL6 mice were enriched and cocultured for in vitro experiments. Results, as obtained in both LT patients and LT mice model, revealed that the proportion and frequency of M-MDSC and PD-1 + T-cells increased significantly under conditions associated with a high degree of LT rejection. Within the LT rejection group, our immunofluorescence results showed that a close spatial contiguity was present between PD-1 + T-cells and M-MDSCs in these liver tissue samples and the proportion of CD84/PD-L1 double-positive M-MDSC was greater than that of G-MDSC. There was a positive correlation between the activity of CD84 and immunosuppressive function of M-MDSCs including PD-L1 expression and reactive oxygen species (ROS) production, as demonstrated in our in vitro model. M-MDSCs treated with CD84 protein were able to induce co-cultured CD8 + T-cells to express high levels of exhaustion markers. We found that CD84 regulated M-MDSC function via expression of PD-L1 through activation of the Akt/Stat3 pathway. These results suggest that the capacity for CD84 to regulate M-MDSC induction of CD8 + T-cell exhaustion may play a key role in LT rejection. Such findings provide important, new insights into the mechanisms of tolerance induction in LT.