Comparison and development of advanced machine learning tools to predict nonalcoholic fatty liver disease: An extended study.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a public health challenge and significant cause of morbidity and mortality worldwide. Early identification is crucial for disease intervention. We recently proposed a nomogram-based NAFLD prediction model from a large population cohort. We aimed to explore machine learning tools in predicting NAFLD. METHODS: A retrospective cross-sectional study was performed on 15 315 Chinese subjects (10 373 training and 4942 testing sets). Selected clinical and biochemical factors were evaluated by different types of machine learning algorithms to develop and validate seven predictive models. Nine evaluation indicators including area under the receiver operating characteristic curve (AUROC), area under the precision-recall curve (AUPRC), accuracy, positive predictive value, sensitivity, F1 score, Matthews correlation coefficient (MCC), specificity and negative prognostic value were applied to compare the performance among the models. The selected clinical and biochemical factors were ranked according to the importance in prediction ability. RESULTS: Totally 4018/10 373 (38.74%) and 1860/4942 (37.64%) subjects had ultrasound-proven NAFLD in the training and testing sets, respectively. Seven machine learning based models were developed and demonstrated good performance in predicting NAFLD. Among these models, the XGBoost model revealed the highest AUROC (0.873), AUPRC (0.810), accuracy (0.795), positive predictive value (0.806), F1 score (0.695), MCC (0.557), specificity (0.909), demonstrating the best prediction ability among the built models. Body mass index was the most valuable indicator to predict NAFLD according to the feature ranking scores. CONCLUSIONS: The XGBoost model has the best overall prediction ability for diagnosing NAFLD. The novel machine learning tools provide considerable beneficial potential in NAFLD screening.

Association between ADIPOQ gene polymorphisms and the risk of new-onset diabetes mellitus after liver transplantation.

BACKGROUND: New-onset diabetes after transplantation (NODAT) has become one of the major factors that affect the overall survival and long-term life quality in liver transplantation (LT) recipients. Previous studies found that the serum adiponectin concentration of diabetic patients is significantly lower than that of healthy subjects. Adiponectin regulates the blood glucose level by increasing body sensitivity to insulin through various mechanisms. In this study, we aimed to investigate the impact of diabetes related gene polymorphisms on the development of NODAT in liver recipients. METHODS: A total of 256 LT patients in a single-center were selected retrospectively for the study. Genomic DNA was extracted from explanted liver tissues, and tested for twelve diabetes mellitus associated single nucleotide polymorphisms by Sequenom MassARRAY. Modified clinical models in predicting NODAT were established and evaluated. RESULTS: The GG genotype of ADIPOQ rs1501299 gene polymorphism was significantly more frequent in NODAT than non-NODAT LT patients (56% vs 39%, P=0.014). Dominant model (GG vs GT+TT, P=0.030) and recessive model (GT+GG vs TT, P=0.005) also confirmed the genotype distribution difference between NODAT and non-NODAT groups. Age (OR=1.048, P=0.004), BMI (OR=1.107, P=0.041), and blood tacrolimus level at 1-month LT (OR=1.170, P=0.003) were clinical independent risk factors of NODAT. Furthermore, rs1501299 could improve the ability of clinical model in predicting NODAT (AUROC=0.743, P<0.001). CONCLUSION: ADIPOQ rs1501299 gene polymorphism is associated with an increased risk of NODAT, which should be added to the clinical models in predicting the occurrence of NODAT in LT recipients.

FBW7 increases chemosensitivity in hepatocellular carcinoma cells through suppression of epithelial-mesenchymal transition.

BACKGROUND: FBW7 is a tumor suppressor which regulates a network of proteins with central roles in cell division, cell growth and differentiation. This study aimed to evaluate the role of FBW7 in chemosensitivity and epithelial-mesenchymal transition (EMT) in different hepatocellular carcinoma (HCC) cell lines and to investigate the relevant underlying mechanisms. METHODS: Different human HCC cell lines (Hep3B, Huh-7, and SNU-449) were cultured. The cell viability was evaluated by cell counting kit-8, and FBW7 mRNA transcription and protein expression were quantitated by real-time PCR and Western blotting. Expressions of vimentin (mesenchymal biomarker) and E-cadherin (epithelial biomarker) were evaluated by Western blotting and immunocytochemistry. Cell invasion was assayed by Transwell migration, and FBW7 plasmid or siRNA was used to evaluate the effect of FBW7 overexpression or silencing on cell chemosensitivity. RESULTS: FBW7 expression affected tumor cell chemosensitivity to doxorubicin and tumor cell invasive capacity in different HCC cell lines. FBW7hi (high FBW7 expression) Hep3B and FBW7mi (median FBW7 expression) Huh-7 cells were more sensitive to doxorubicin and lower in invasive capacity than FBW7lo (low FBW7 expression) SNU-449 cells. Silencing of FBW7 in Huh-7 and Hep3B cells induced the resistance to doxorubicin and enhanced cell invasion, whereas overexpression of FBW7 in SNU-449 cells restored the sensitivity to doxorubicin and significantly reduced invasive capacity. Furthermore, doxorubicin induced EMT toward mesenchyme in HCC cells. Downregulation of FBW7 in Huh-7 and Hep3B cells or upregulation of FBW7 in SNU-449 cells altered the direction of EMT. CONCLUSIONS: The level of FBW7 expression impacted the tumor resistance to doxorubicin and the invasion capability of HCC cells. FBW7 therefore may be a potential target for the chemotherapy of HCC through the regulation of EMT.

Ischemic preconditioning enhances hepatocyte proliferation in the early phase after ischemia under hemi-hepatectomy in rats.

BACKGROUND: Ischemia/reperfusion (I/R) injury is an important barrier to liver surgery and transplantation because it impairs remnant liver/reduced-size-graft regeneration. Ischemic preconditioning (IPC), as an effective measure to overcome I/R injury, has been shown to enhance the regenerative capacity of hepatocytes. However, investigations have always focused on regeneration in the late phase after reperfusion. This study aimed to investigate whether IPC enhances hepatocyte proliferation in the early phase after reperfusion and possible underlying mechanisms. METHODS: A total of 90 rats were divided into three groups: hemi-hepatectomy alone (PHx group), 60 minutes of ischemia plus hemi-hepatectomy (I/R group), and a cycle of 10 minutes of alternating I/R prior to 60 minutes of ischemia plus hemi-hepatectomy (IPC group). Each group was divided into five subgroups sacrificed after 0.5, 2, 6, 12 or 24 hours (n=6/subgroup). Subsequently, serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) were measured; caspase-3 and proliferating cell nuclear antigen (PCNA) proteins were also determined by Western blotting. Furthermore, PCNA was detected by immunohistochemistry to identify the expression site. RESULTS: Serum ALT and AST levels after 2-24 hours of reperfusion in the PHx and IPC groups were remarkably decreased compared to the I/R group, and the serum TNF-alpha was relatively lower. A significant increase of serum IL-6 levels was found in the PHx and IPC groups compared with the I/R group at each time point. Furthermore, PCNA expression was remarkably increased in the IPC group after 6-12 hours of reperfusion, and in the earlier 0.5 and 6 hours time points after reperfusion have shown the massive PCNA-positive hepatocytes. At the same time, the expression of liver p-JNK was higher in the IPC group in the early phase after reperfusion than that of the I/R group and its expression was consistent with the PCNA. CONCLUSION: IPC can initiate hepatocyte proliferation in the early phase after ischemia under hemi-hepatectomy, and may be associated with p-JNK expression and triggered by TNF-alpha/IL-6 signals.

Outcomes and mechanisms of ischemic preconditioning in liver transplantation.

BACKGROUND: Liver transplantation is so far the most effective therapeutic modality for end-stage liver diseases, but ischemia/reperfusion (I/R) injury represents a critical barrier to liver transplantation. Primary graft dysfunction and small-for-size syndrome are closely associated with I/R injury. Ischemic preconditioning (IPC) is defined as a brief period of liver ischemia followed by reperfusion, and has demonstrated protections against a prolonged I/R injury and improved the capacity of regeneration. The article aimed to review IPC literatures for the understanding of the effects of IPC on I/R injury involving in the procurement of donor liver and protective mechanisms. DATA SOURCES: A literature search of MEDLINE and Web of Science databases using "liver transplantation", "liver regeneration", "hepatectomy", "ischemia/reperfusion" and "ischemic preconditioning" was performed, and then a large amount of related data was collected. RESULTS: The literature search provided a huge amount of evidence for the protective effects of IPC on I/R injury in liver transplantation, including reduction of blood loss in hepatectomy, intraoperative hemodynamic stability and its significant role in liver regeneration. The mechanism involves in balancing inflammatory cytokines, enhancing energy status and mitigating microcirculatory disturbance. CONCLUSION: IPC plays an essential role in hepatectomy before and after harvest of living donor liver and implantation of liver graft.

Ischemic preconditioning attenuates morphological and biochemical changes in hepatic ischemia/reperfusion in rats.

OBJECTIVE: Ischemic preconditioning (IPC) has been gradually introduced into clinical liver surgery and transplantation in recent years. However, the protective effects of IPC on hepatic warm ischemia/reperfusion (I/R) injury and the potential mechanisms involved are not fully understood. We aimed to evaluate whether the reduction of apoptotic sinusoidal endothelial cells (SECs), induced by IPC, contributes to its protective effect. METHODS: Male Wistar rats were randomized into three experimental groups: the continuous clamping group underwent 60 min of 70% hepatic ischemia; the IPC group received 10 min ischemia followed by 10 min reperfusion prior to ischemia, and the sham control (sham) underwent a sham operation without ischemia. Hepatocyte and SEC apoptosis, liver necrotic areas and the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid, tumor necrosis factor, myeloperoxidase (MPO) and malondialdehyde were determined. Expression of cysteine-aspartic acid protease-3 (caspase-3) in hepatocytes and SECs was also investigated. Furthermore, the hepatic leukocyte infiltration was assessed by intravital fluorescence microscopy. RESULTS: IPC exhibited a significant alleviation of their postischemic liver function. Serum AST, ALT and tissue MPO were significantly decreased by IPC, and the degree of hepatocyte and SEC apoptosis was significantly inhibited, as shown by the decreased numbers of adherent leukocytes. CONCLUSIONS: IPC attenuates hepatic I/R injury by the reduction of leukocyte infiltration, the reduction hepatic enzymatic leakage and the depression of apoptotic cells. SECs are more sensitive to apoptosis induced by warm I/R injury compared to hepatocytes.

Sirolimus attenuates reduced-size liver ischemia-reperfusion injury but impairs liver regeneration in rats.

BACKGROUND: Evidence has suggested that immunosuppressive drugs impact ischemia-reperfusion injury. AIMS: The purpose of the present study was to evaluate the effect of sirolimus on hepatic injury and regeneration in a rat reduced-size liver ischemia-reperfusion model. METHODS: Using a newly developed rat reduced-size liver ischemia-reperfusion injury model, the effects of sirolimus were evaluated by assessing liver cell apoptosis and aspartate aminotransferase, myeloperoxidase, and malondialdehyde levels. In addition, liver regeneration after sirolimus treatment was evaluated by measuring liver weight resumption and by the histological examination of bromodeoxyuridine and proliferating cell nuclear antigen expression. RESULTS: Sirolimus significantly decreased liver cell apoptosis as well as tissue myeloperoxidase and malondialdehyde levels, but impaired postischemic liver regeneration. Ischemia-reperfusion-induced elevation of aspartate aminotransferase serum levels was significantly decreased by sirolimus. CONCLUSIONS: Despite an impairment of postischemic liver proliferation, sirolimus demonstrated beneficial amelioration of ischemia-reperfusion-induced liver injury in a reduced-size liver model in rats.

Mycophenolate mofetil attenuates liver ischemia/reperfusion injury in rats.

Mycophenolate mofetil (MMF) has been gradually introduced into clinical liver transplantation in recent years. However, the effects of MMF on hepatic ischemia/reperfusion (I/R) injury and the potential mechanisms involved are not totally understood. We aimed to evaluate whether MMF could attenuate hepatic I/R injury. MMF (20 mg/kg) or vehicle was administered to Wistar rats by gavage. The rats were then subjected to hepatic ischemia. Liver cell apoptosis and the levels of aspartate aminotransferase, myeloperoxidase (MPO), xanthine oxidase (XOD) and malondialdehyde (MDA) were determined. Expression of vascular cell adhesion molecule-1 (VCAM-1) and activation of mitogen-activated protein kinases (MAPKs) were also investigated. Furthermore, the hepatic microcirculation was observed by intravital fluorescence microscopy. Rats pretreated with MMF exhibited significant alleviation of their postischemic liver function. Liver cell apoptosis and the tissue MPO, XOD and MDA levels were decreased by MMF pretreatment. MMF also improved I/R-induced hemodynamic turbulence, as evidenced by reduced hepatic perfusion failure and decreased numbers of rolling and adherent leukocytes. I/R injury induced activation of the MAPKs pathway while expression of VCAM-1 was downregulated by MMF pretreatment. In summary, MMF attenuates hepatic I/R injury through suppression of the production of reactive oxygen species and amelioration of postischemic microcirculatory disturbances.