The role of normothermic machine perfusion (NMP) in the preservation of ex-vivo liver before transplantation: A review.

The discrepancy between the number of patients awaiting liver transplantation and the number of available donors has become a key issue in the transplant setting. There is a limited access to liver transplantation, as a result, it is increasingly dependent on the use of extended criteria donors (ECD) to increase the organ donor pool and address rising demand. However, there are still many unknown risks associated with the use of ECD, among which preservation before liver transplantation is important in determining whether patients would experience complications survive after liver transplantation. In contrast to traditional static cold preservation of donor livers, normothermic machine perfusion (NMP) may reduce preservation injury, improve graft viability, and potentially ex vivo assessment of graft viability before transplantation. Data seem to suggest that NMP can enhance the preservation of liver transplantation to some extent and improve the early outcome after transplantation. In this review, we provided an overview of NMP and its application in ex vivo liver preservation and pre-transplantation, and we summarized the data from current clinical trials of normothermic liver perfusion.

CKAP4-mediated activation of FOXM1 via phosphorylation pathways regulates malignant behavior of glioblastoma cells.

OBJECTIVE: CKAP4 (Cytoskeleton Associated Protein 4) has been reported as an important regulator of carcinogenesis. A great deal of uncertainty still surrounds the possible molecular mechanism of CKAP4 involvement in GBM. We aimed to specifically elucidate the putative role of CKAP4 in the development of GBM. METHODS: We identified divergent proteomics landscapes of GBM and adjacent normal tissues using mass spectrometry-based label-free quantification. Bioinformatics analysis of differentially expressed proteins (DEPs) led to the identification of CKAP4 as a hub gene. Based on the Chinese Glioma Genome Atlas data, we characterized the elevated expression of CKAP4 in GBM and developed a prognostic model. The influence of CKAP4 on malignant behavior of GBM was detected in vitro and vivo, as well as its downstream target and signaling pathways. RESULTS: The prognosis model displayed accuracy and reliability for the probability of survival of patients with gliomas. CKAP4 knockdown remarkably reduced the malignant potential of GBM cells, whereas its overexpression reversed these effects in GBM cells and xenograft mice. Moreover, we demonstrated that overexpression of CKAP4 leads to increased FOXM1 (Forkhead Box M1) expression in conjunction with an increased level of AKT and ERK phosphorylation. Inhibition of both pathways had synergistic effects, resulting in greater effectiveness of inhibition. CKAP4 could reverse the deregulation of FOXM1 triggered by inhibition of AKT and ERK signaling. CONCLUSIONS: This is the first study to reveal a CKAP4-FOXM1 signaling cascade that contributes to the malignant phenotype of GBMs. The CKAP4-based prognostic model would facilitate individualized treatment decisions for glioma patients.

Application of polymerized porcine hemoglobin in the ex vivo normothermic machine perfusion of rat livers.

Background: In contrast to traditional static cold preservation of donor livers, normothermic machine perfusion (NMP) may reduce preservation injury, improve graft viability and potentially allows ex vivo assessment of graft viability before transplantation. The polymerized porcine hemoglobin is a kind of hemoglobin oxygen carrier prepared by crosslinking porcine hemoglobin by glutaraldehyde to form a polymer. The pPolyHb has been proved to have the ability of transporting oxygen which could repair the organ ischemia-reperfusion injury in rats. Objective: In order to evaluate the effectiveness of rat liver perfusion in vitro based on pPolyHb, we established the NMP system, optimized the perfusate basic formula and explored the optimal proportion of pPolyHb and basal perfusate. Methods: The liver was removed and perfused for 6 h at 37°C. We compared the efficacy of liver perfusion with different ratios of pPolyHb. Subsequently, compared the perfusion effect using Krebs Henseleit solution and pPolyHb perfusate of the optimal proportion, and compared with the liver preserved with UW solution. At 0 h, 1 h, 3 h and 6 h after perfusion, appropriate samples were collected for blood gas analysis and liver injury indexes detection. Some tissue samples were collected for H&E staining and TUNEL staining to observe the morphology and detect the apoptosis rate of liver cells. And we used Western Blot test to detect the expression of Bcl-2 and Bax in the tissues. Results: According to the final results, the optimal addition ratio of pPolyHb was 24%. By comparing the values of Bcl-2/Bax, the apoptosis rate of pPolyHb group was significantly reduced. Under this ratio, the results of H&E staining and TUNEL staining showed that the liver morphology was well preserved without additional signs of hepatocyte ischemia, biliary tract injury, or hepatic sinusoid injury, and hepatocyte apoptosis was relatively mild. Conclusion: Through the above-mentioned study we show that within 6 h of perfusion based on pPolyHb, liver physiological and biochemical activities may essentially be maintained in vitro. This study demonstrates that a pPolyHb-based perfusate is feasible for NMP of rat livers. This opens up a prospect for further research on NMP.

Cooperative Coevolution with Formula-Based Variable Grouping for Large-Scale Global Optimization.

For a large-scale global optimization (LSGO) problem, divide-and-conquer is usually considered an effective strategy to decompose the problem into smaller subproblems, each of which can then be solved individually. Among these decomposition methods, variable grouping is shown to be promising in recent years. Existing variable grouping methods usually assume the problem to be black-box (i.e., assuming that an analytical model of the objective function is unknown), and they attempt to learn appropriate variable grouping that would allow for a better decomposition of the problem. In such cases, these variable grouping methods do not make a direct use of the formula of the objective function. However, it can be argued that many real-world problems are white-box problems, that is, the formulas of objective functions are often known a priori. These formulas of the objective functions provide rich information which can then be used to design an effective variable group method. In this article, a formula-based grouping strategy (FBG) for white-box problems is first proposed. It groups variables directly via the formula of an objective function which usually consists of a finite number of operations (i.e., four arithmetic operations "+", "-", "×", "÷" and composite operations of basic elementary functions). In FBG, the operations are classified into two classes: one resulting in nonseparable variables, and the other resulting in separable variables. In FBG, variables can be automatically grouped into a suitable number of non-interacting subcomponents, with variables in each subcomponent being interdependent. FBG can easily be applied to any white-box problem and can be integrated into a cooperative coevolution framework. Based on FBG, a novel cooperative coevolution algorithm with formula-based variable grouping (so-called CCF) is proposed in this article for decomposing a large-scale white-box problem into several smaller subproblems and optimizing them respectively. To further enhance the efficiency of CCF, a new local search scheme is designed to improve the solution quality. To verify the efficiency of CCF, experiments are conducted on the standard LSGO benchmark suites of CEC'2008, CEC'2010, CEC'2013, and a real-world problem. Our results suggest that the performance of CCF is very competitive when compared with those of the state-of-the-art LSGO algorithms.

Biosynthesis of 3″-demethyl-gentamicin C components by genN disruption strain of Micromonospora echinospora and test their antimicrobial activities in vitro.

Gentamicin consists primarily of four components, which have different patterns of methylation at C-6' position. The methyl groups have a significant impact on gentamicin antimicrobial activity. Sequence analysis predicted that GenN was a methyltransferase in the gentamicin biosynthetic pathway. To study the function of genN, it was disrupted in Micromonospora echinospora. The genN disruption strains produced 3″-N-demethyl-gentamicin C complex instead of the gentamicin C complex. In this study, 3″-N-demethyl gentamicin C1a was purified from the broth of disruption strain, and its structure was elucidated using MS and NMR. Besides 3″-N-demethyl products corresponding to gentamicin C1a, C2, and C2a, two 3″-N-demethyl products corresponding to gentamicin C1 were detected, which were concluded as C-6' epimers originating from decreased substrate specificity of 6'-N methyltransferase. To explore the effects of 3″-N-methyl on gentamicin antimicrobial activity, antimicrobial activity of these demethyl gentamicin analogues were tested in vitro. 3″-N-Demethyl gentamicin components have identical activity with corresponding components of gentamicin. The results of bioassays showed that the 3″-N-methyl group has little impact on gentamicin activity. However, these highly bioactive compounds afforded a unique opportunity for creating new and high potent aminoglycoside antibiotics.