Tonghai Xing

Multidrug-resistant gram-negative bacterial infections after liver transplantation – Spectrum and risk factors

OBJECTIVES Gram-negative bacilli infections, especially multidrug-resistant gram-negative bacilli infections, are the leading cause of high mortality after liver transplantation. This study sought to investigate the type of infection, infection rate, pathogenic spectrum, antibiotic-resistance profile, risk factors, and epidemiology of multidrug-resistant gram-negative bacterial infection. METHODS A retrospective cohort study was conducted and data of 217 liver transplant patients receiving cadaveric livers between January 2007 and April 2010 were analyzed. Antibiotic susceptibility was determined by minimum inhibitory concentration test. Extended-spectrum and metallo-β-lactamase assays were used to analyze β-lactamase-produced isolates, and repetitive-sequence polymerase chain reaction was used to differentiate bacterium subspecies. RESULTS Sixty-seven isolates of multidrug-resistant gram-negative bacteria were isolated from 66 infected liver transplant patients. Stenotrophomonas maltophilia (100%, 8/8), Klebsiella pneumoniae (61.5%, 8/13), Enterobacter cloacae (75%, 3/4) and Escherichia coli (81.3%, 13/16) were the most common extended-spectrum β-lactamase-producing bacilli. Metallo-β-lactamase expressing isolates were identified as S. maltophilia (100%, 8/8), Pseudomonas aeruginosa (83.3%, 5/6), Acinetobacter baumannii (95%, 19/20). Significant independent risk factors for multidrug-resistant gram-negative infection were extended use of pre-transplant broad-spectrum antibiotics (OR 9.027, P=0.001) and prolonged (≧72h) endotracheal intubation (OR 3.537, P=0.033). CONCLUSIONS To reduce the risk of acquiring MDR gram-negative bacillus infections after liver transplant, control measures are required to limit the use of prophylactic antibiotic in preventing infection during liver transplant and to shorten endotracheal intubation time.

Phospholipase C epsilon plays a suppressive role in incidence of colorectal cancer

In our previous study, we have found that PLCE1 was down-regulated in sporadic colorectal cancer. But the role of PLCE1 in the incidence of colorectal cancer is still not definite. Therefore, in order to validate whether PLCE1 displays a suppressive role, in this study, we examined the expression of PLCE1 in sporadic colorectal cancer with a larger sample size and the effect of PLCE1 overexpression on cancer cell malignant degree. The expression level of PLCE1 in 50 colorectal cancers with their pair-matched normal tissues was measured by RT-PCR, Western blot, and immunohistochemistry. The effect of PLCE1 overexpression on cancer cell malignant degree was measured by MTT assay, plate colony formation assay, soft agar colony formation assay, cell cycle and apoptosis analysis, and xenograft assay. We found that PLCE1 was down-regulated in 42% (21/50) of colorectal cancer tissues compared with pair-matched normal tissues, more frequent in the poor differentiation tumor in patients under 60. Overexpression of PLCE1 significantly inhibited the proliferation of colon cancer cells and degraded its malignant degree. These results suggest that PLCE1 may be involved in the development of sporadic colorectal cancer through its inhibitory effect on cell proliferation. PLCE1 exhibits a suppressive role in incidence of colorectal cancer.

Experience of combined liver-kidney transplantation for acute-on-chronic liver failure patients with renal dysfunction.

BACKGROUND The aim of this study was to evaluate the outcomes of orthotopic liver transplantation (OLT) or combined liver-kidney transplantation (CLKT) for acute-on-chronic liver failure (ACLF) patients with renal dysfunction. METHODS From January 2001 to December 2009, 133 patients underwent OLT for ACLF at our center. Among them, 30 had both ACLF and renal dysfunction. Of the 30 patients, 12 underwent CLKT for end-stage renal disease (ESRD), and the other 18 with hepatorenal syndrome type 1 (HRS1) underwent OLT alone. ACLF was defined according to the Asian Pacific Association for the Study of Liver Consensus Meeting. Clinical data were reviewed for survival outcomes. RESULTS The median model for end-stage liver disease score (MELD) of patients with ACLF was 28. Among the 133 patients, all of whom received deceased donor liver grafts, 12 also got the kidney grafts from the same deceased donor. The hospital mortality rate was 21.8% for all patients with ACLF. The 5-year survival rates were 72.8% for patients without renal dysfunction and 70% for patients with renal dysfunction. The results of patients with ESRD who underwent CLKT were better than those of subjects without renal dysfunction or patients with HRS1 who underwent OLT alone. CONCLUSIONS OLT alone improved renal function in most patients with HRS1, including those requiring short-term hemodialysis. Simultaneous liver-kidney transplantation was an excellent strategy for patients with both ACLF and ESRD. It provided protection to the kidney allograft for liver-based metabolic diseases affecting the kidney. The rate of acute rejection episodes in kidneys was low.

Prevalence of multidrug-resistant gram-negative bacilli producing extended-spectrum β-lactamases (ESBLs) and ESBL genes in solid organ transplant recipients

Multidrug‐resistant (MDR) gram‐negative bacilli pose a serious and rapidly emerging threat to recipients of solid organ transplants (SOTs). However, extended‐spectrum β‐lactamases (ESBLs), as one of the cardinal mechanisms of resistance to antimicrobial agents in SOT recipients, remain obscure. The aim of this study was to investigate the prevalence of strains producing ESBLs in SOT patients with MDR gram‐negative bacilli infections and to identify the ESBL genes carried by them.

1,25(OH)2D3 induces regulatory T cell differentiation by influencing the VDR/PLC-γ1/TGF-β1/pathway

Highlights1,25(OH)2D3 induces regulatory T cells, while suppressing the differentiation of Th17 cells in Jurkat E clone 6,1 cells.1,25(OH)2D3 induces expression of cytokines TGF‐&bgr;1, and inhibits the secretion of pro‐inflammatory cytokines IL‐17A.1,25(OH)2D3 upregulates the expression of PLC‐&ggr;1 and TGF‐&bgr;1. PLC‐&ggr;1 is involved in inducing TGF‐&bgr;1 gene coding.1,25(OH)2D3 induces the Tregs differentiation through modulating VDR/PLC‐&ggr;1/TGF‐&bgr;1 pathway. &NA; Vitamin D has been recommended as an immune modulator in recent years, in addition to regulating calcium‐phosphorous‐bone metabolism. Clinical studies on organ transplantation found that vitamin D sufficiency patients were less likely to develop acute cellular rejection within one year after transplantation compared to those with vitamin D deficiency. Thus, a high percentage of regulatory T cells might play a key role in preventing acute cellular rejection (ACR). In this report, we studied the specific effects of 1,25(OH)2D3 on human T cell diff; erentiation, and determined the potential molecule mechanism behind. Results showed that 1,25(OH)2D3 induced the differentiation of T‐regulatory cells (Treg cells), while inhibiting Th17 cell proliferation. In addition, 1,25(OH)2D3 promoted secretion of the anti‐inflammatory cytokine, transforming Growth Factor beta1 (TGF‐&bgr;1) but suppressed pro‐inflammatory cytokines such as interleukin‐17 (IL‐17). Phospholipase C gamma 1 (PLC‐&ggr;1) is an indispensable signaling protein downstream of the classical TCR signaling pathway and was shown to play a crucial role in T cell activation, while Naive T cells expressed less PLC‐&ggr;1. Here we showed that Vitamin D could significantly upregulate PLC‐&ggr;1 expression, which then induced expression of TGF‐&bgr;1. In summary, 1,25(OH)2D3 indirectly modulates the differentiation of Treg/Th17 cells by aff; ecting the VDR/PLC‐&ggr;1/TGF‐&bgr;1pathway. These results indicate that administration 1,25(OH)2D3 supplements may be a beneficial treatment for organ transplantation recipients.

Mapping of hepatic expression quantitative trait loci (eQTLs) in a Han Chinese population

Background Elucidating the genetic basis underlying hepatic gene expression variability is of importance to understand the aetiology of the disease and variation in drug metabolism. To date, no genome-wide expression quantitative trait loci (eQTLs) analysis has been conducted in the Han Chinese population, the largest ethnic group in the world. Methods We performed a genome-wide eQTL mapping in a set of Han Chinese liver tissue samples (n=64). The data were then compared with published eQTL data from a Caucasian population. We then performed correlations between these eQTLs with important pharmacogenes, and genome-wide association study (GWAS) identified single nucleotide polymorphisms (SNPs), in particular those identified in the Asian population. Results Our analyses identified 1669 significant eQTLs (false discovery rate (FDR) < 0.05). We found that 41% of Asian eQTLs were also eQTLs in Caucasians at the genome-wide significance level (p=10−8). Both cis- and trans-eQTLs in the Asian population were also more likely to be eQTLs in Caucasians (p<10−4). Enrichment analyses revealed that trait-associated GWAS-SNPs were enriched within the eQTLs identified in our data, so were the GWAS-SNPs specifically identified in Asian populations in a separate analysis (p<0.001 for both). We also found that hepatic expression of very important pharmacogenetic (VIP) genes (n=44) and a manually curated list of major genes involved in pharmacokinetics (n=341) were both more likely to be controlled by eQTLs (p<0.002 for both). Conclusions Our study provided, for the first time, a comprehensive hepatic eQTL analysis in a non-European population, further generating valuable data for characterising the genetic basis of human diseases and pharmacogenetic traits.

Comparison of Steroid-Free Immunosuppression and Standard Immunosuppression for Liver Transplant Patients with Hepatocellular Carcinoma

Immunosuppression therapy following liver transplantation often includes steroids. However, extended corticosteroid therapy is associated with numerous complications. This study evaluated the efficacy and safety of using basiliximab in place of a corticosteroid for immunosuppression following liver transplantation for hepatocellular carcinoma (HCC) in Chinese patients. The records of 178 patients with HCC who underwent orthotopic liver transplantation from January 2003 to December 2009 were retrospectively reviewed. All patients received immunosuppression therapy that contained either basiliximab (n = 78) or steroids (n = 100) in addition to tacrolimus and mycophenolate mofetil. Assessments included complications related to liver transplantation, occurrence of steroid side effects, recurrence of HCC, and patient and graft survival. A smaller proportion of patients receiving basiliximab compared with steroids experienced de novo diabetes (38.7% vs. 91.0%, respectively) or long-term de novo diabetes mellitus (7.7% vs. 38.0%, respectively) (both, P<0.0001). The median overall and disease free survival was similar between basiliximab (50.8 months and 19.6 months, respectively) and steroid treated patients (64.2 months and 23.8 months, respectively). The 5-year overall survival and disease free survival rates was also similar between the basiliximab (42.5% and 38.9%, respectively) and steroid (50.5% and 39.2%) groups (all, P>0.730). However, in patients who met the Milan criteria basiliximab was associated with greater 5-year overall survival rate as compared with steroid therapy (88.9% vs. 57.4%, respectively, P = 0.022). These findings provide further evidence of the negative impact of steroids as a part of immunosuppression therapy following liver transplantation for HCC.

Donor IL-18 rs5744247 polymorphism as a new biomarker of tacrolimus elimination in Chinese liver transplant patients during the early post-transplantation period: results from two cohort studies.

AIM This study evaluated the relationships between IL-18 polymorphisms and tacrolimus elimination in Chinese liver transplant patients. PATIENTS & METHODS Eighty-four liver transplant patients from Shanghai (training set) and 50 patients from Shandong (validating set) were inculded. IL-18 polymorphisms (rs5744247, rs7106524, rs549908, rs187238 and rs1946518) and CYP3A5 rs776746 were genotyped. RESULTS In training set, daily drug dose, total bilirubin, donor CYP3A5 rs776746 and IL-18 rs5744247 genotypes were screened to construct prediction model for tacrolimus elimination. This model was confirmed in validating set (p < 0.001). Donor IL-18 rs5744247 polymorphism was an independent predictor of tacrolimus elimination in the first week after transplantation in both training (p = 0.008) and validating cohorts (p = 0.033). CONCLUSION Donor IL-18 rs5744247 polymorphism may influence on tacrolimus elimination. Original submitted 16 July 2014; Revision submitted 12 November 2014.

Effect of ursodeoxycholic acid administration after liver transplantation on serum liver tests and biliary complications: a randomized clinical trial.

Background/Aims: Endogenous hydrophobic bile acids are suspected to be one of the pathogenetic factors of biliary complications after orthotopic liver transplantation (OLT). This study was designed to investigate the effects of hydrophilic ursodeoxycholic acid (UDCA) administration early after OLT on serum liver tests and the incidence of biliary complications. Methods: 112 adult patients undergoing OLT from donation after cardiac death (DCD) were randomized to UDCA (13–15 mg/kg/day for 4 weeks; 56 patients) or placebo (56 patients). Serum liver tests and serum bile acids of all patients and biliary bile acids in patients with T-tube drainage were determined during the 4 weeks after OLT. Biliary complications as well as patient and graft survival were analyzed during a mean follow-up of 41.6 months. Results: UDCA treatment decreased ALT, AST and GGT (p < 0.05) during the 4 weeks after OLT and the incidence of biliary sludge and casts within the 1st year (p < 0.05). However, no differences in the incidence of other biliary complications as well as 1-, 3- and 5-year graft and patient survival were observed. Conclusions: UDCA administration early after DCD-OLT improves serum liver tests and decreases the incidence of biliary sludge and casts within the 1st postoperative year but does not affect overall outcome up to 5 years after OLT.

Intraoperative cryoprecipitate transfusion and its association with the incidence of biliary complications after liver transplantation--a retrospective cohort study.

Background Cryoprecipitate is largely used for acquired hypofibrinogenemia in the setting of massive hemorrhage in liver transplantation (LT). However, the influence of intraoperative cryoprecipitate transfusion on biliary complications (BC) after LT has not been studied in detail. Study Design and Methods In a series of 356 adult patients who received their first LT, the causes of BC were retrospectively studied by multivariate logistic regression analysis. The clinical relationship between intraoperative cryoprecipitate transfusion and BC occurrence was studied through a retrospective cohort study in patients. All patients received follow-ups for one year, and, during the follow-up period, the time of BC occurrence and liver biopsies were recorded. Results Intraoperative cryoprecipitate transfusion (RR = 3.46, 95% CI [1.72–6.97], P<0.001), cold ischemia time >8 h (RR = 4.24, 95% CI [2.28–7.92], P<0.01), and high-level Child-Pugh ( RR = 1.71, 95% CI [1.11–2.63], P = 0.014) are independent risk factors to predict BC after LT according to time-to-event analysis. One year BC-free survival probability of patients received intraoperative cryoprecipitate transfusions was significantly lower when compared to the group that received no cryoprecipitate(P<0.001). Moreover, BC patients in the cryoprecipitate transfusion group owned different liver pathological feature, pathological micro-thrombus formation and cholestasis were seen more often (41.4% vs 0%, 62.1% vs 12.5%, respectively) than no cryoprecipitate transfusion group. Conclusion These findings suggested that intraoperative cryoprecipitate transfusion was associated with BC after LT. The mechanism of BC occurrence might involve micro-thrombus formation and immune rejection.