Chemokines: reliable markers for diagnosis of rejection and inflammation following orthotopic liver transplantation

Chemokines in chronic liver allograft dysfunction pathogenesis and potential therapeutic targets

Despite advances in immunosuppressive drugs, long-term success of liver transplantation is still limited by the development of chronic liver allograft dysfunction. Although the exact pathogenesis of chronic liver allograft dysfunction remains to be established, there is strong evidence that chemokines are involved in organ damage induced by inflammatory and immune responses after liver surgery. Chemokines are a group of low-molecular-weight molecules whose function includes angiogenesis, haematopoiesis, mitogenesis, organ fibrogenesis, tumour growth and metastasis, and participating in the development of the immune system and in inflammatory and immune responses. The purpose of this review is to collect all the research that has been done so far concerning chemokines and the pathogenesis of chronic liver allograft dysfunction and helpfully, to pave the way for designing therapeutic strategies and pharmaceutical agents to ameliorate chronic allograft dysfunction after liver transplantation.

Preservation solutions for liver transplantation in adults: celsior versus custodiol: a systematic review and meta-analysis with an indirect comparison of randomized trials

BACKGROUND

The University of Wisconsin (UW) solution has been recognized as the gold standard for liver preservation; however, it possesses some limitations, and other solutions exist for organ preservation. The aim of this study was to compare the liver functions of transplanted grafts that had been stored in Celsior and Custodiol solutions.

METHODS

We searched the MEDLINE, EMBASE, LILACS, Cochrane Central Register of Controlled Trials, and SCIELO databases. We included randomized and quasi-randomized, controlled trials that compared the efficacy and safety of Celsior and Custodiol with UW solution for liver preservation in adults. The factors that were considered for analysis were their impacts on primary dysfunction (primary nonfunction and initial poor function), ischemic-type biliary lesions, and patient and graft survival rates. Because of the lack of direct evidence, an indirect comparison of Celsior and Custodiol was calculated.

RESULTS

We identified 3 randomized controlled trials and 1 quasi-randomized, controlled trial to pool in a meta-analysis of Celsior versus UW solutions. The number of episodes of primary dysfunction was lower in the Celsior group (7.4%) than in the UW group (9.8%), but the difference was not significant (relative risk [RR], 0.68; 95% confidence interval [CI], 0.22-1.97). Two randomized controlled trials compared Custodiol and Wisconsin solutions were identified. The number of episodes of primary dysfunction was also lower in the Custodiol group (3.0%) compared with the Wisconsin group (8.4%), but the difference was not significant (RR, 0.36; 95% CI, 0.08-1.70). An indirect comparison using data from the main analysis revealed no difference between the Celsior and Custodiol solutions (RR, 1.88; 95% CI, 0.57-6.16).

CONCLUSION

The Celsior and Custodiol solutions performed similarly to UW solution as preservation solutions in liver transplantation clinical settings.

Long-term survival of transplanted allogeneic cells engineered to express a T cell chemorepellent

BACKGROUND

Alloantigen specific T cells have been shown to be required for allograft rejection. The chemokine, stromal cell derived factor-1 (SDF-1) at high concentration, has been shown to act as a T-cell chemorepellent and abrogate T-cell infiltration into a site of antigen challenge in vivo via a mechanism termed fugetaxis or chemorepulsion. We postulated that this mechanism could be exploited therapeutically and that allogeneic cells engineered to express a chemorepellent protein would not be rejected.

METHODS

Allogeneic murine insulinoma beta-TC3 cells and primary islets from BALB/C mice were engineered to constitutively secrete differential levels of SDF-1 and transplanted into allogeneic diabetic C57BL/6 mice. Rejection was defined as the permanent return of hyperglycemia and was correlated with the level of T-cell infiltration. The migratory response of T-cells to SDF-1 was also analyzed by transwell migration assay and time-lapse videomicroscopy. The cytotoxicity of cytotoxic T cell (CTLs) against beta-TC3 cells expressing high levels of SDF-1 was measured in standard and modified chromium-release assays in order to determine the effect of CTL migration on killing efficacy.

RESULTS

Control animals rejected allogeneic cells and remained diabetic. In contrast, high level SDF-1 production by transplanted cells resulted in increased survival of the allograft and a significant reduction in blood glucose levels and T-cell infiltration into the transplanted tissue.

CONCLUSIONS

This is the first demonstration of a novel approach that exploits T-cell chemorepulsion to induce site specific immune isolation and thereby overcomes allograft rejection without the use of systemic immunosuppression.

Causes and consequences of ischemic-type biliary lesions after liver transplantation

Biliary complications are a major source of morbidity, graft loss, and even mortality after liver transplantation. The most troublesome are the so-called ischemic-type biliary lesions (ITBL), with an incidence varying between 5% and 15%. ITBL is a radiological diagnosis, characterized by intrahepatic strictures and dilatations on a cholangiogram, in the absence of hepatic artery thrombosis. Several risk factors for ITBL have been identified, strongly suggesting a multifactorial origin. The main categories of risk factors for ITBL include ischemia-related injury; immunologically induced injury; and cytotoxic injury, induced by bile salts. However, in many cases no specific risk factor can be identified. Ischemia-related injury comprises prolonged ischemic times and disturbance in blood flow through the peribiliary vascular plexus. Immunological injury is assumed to be a risk factor based on the relationship of ITBL with ABO incompatibility, polymorphism in genes coding for chemokines, and pre-existing immunologically mediated diseases such as primary sclerosing cholangitis and autoimmune hepatitis. The clinical presentation of patients with ITBL is often not specific; symptoms may include fever, abdominal complaints, and increased cholestasis on liver function tests. Diagnosis is made by imaging studies of the bile ducts. Treatment starts with relieving the symptoms of cholestasis and dilatation by endoscopic retrograde cholangiopancreaticography (ERCP) or percutaneous transhepatic cholangiodrainage (PTCD), followed by stenting if possible. Eventually up to 50% of the patients with ITBL will require a retransplantation or may die. In selected patients, a retransplantation can be avoided or delayed by resection of the extra-hepatic bile ducts and construction of a hepaticojejunostomy. More research on the pathogenesis of ITBL is needed before more specific preventive or therapeutic strategies can be developed.

CC chemokine receptor 5delta32 polymorphism-a risk factor for ischemic-type biliary lesions following orthotopic liver transplantation

Ischemic-type biliary lesions are a major complication following orthotopic liver transplantation. They occur in up to 26% of liver transplant recipients. Among other factors, unknown immunologic factors have always been assumed to be partly responsible for these lesions. CC-chemokines and their receptors play a key role in postoperative immunomodulation after liver transplantation. The non-function CC-chemokine receptor 5delta32 polymorphism (CCR5delta32) has been shown to lead to a lower rate of acute rejection after kidney transplantation; in liver transplantation the role of CCR5delta32 is unclear. We investigated the influence of the CCR5delta32 after liver transplantation with special regard to ischemic-type biliary lesions. The CC-chemokine receptor-5 (CCR5) of 146 recipients was analyzed by polymerase chain reaction to detect CCR5delta32 in blood samples of patients after liver transplantation. One hundred twenty patients with wild-type CCR5 and 26 patients with CCR5delta32 (1 homozygote, 25 heterozygote) were identified. Ischemic-type biliary lesions occurred in 14 of 120 patients with wild-type CCR5 and in 8 of 26 patients with CCR5delta32 polymorphism (P = = 0.01). 5 year patient survival with CCR5delta32 and CCR5 was 70% and 85%, respectively (P =.0067). Our results show that the CCR5delta32 is a significant risk factor for the development of ischemic-type biliary lesions after liver transplantation and leads to a reduction in 5-year survival. In conclusion, the CCR5 status should be screened prospectively before liver transplantation.

Differential chemokine expression profiles in human peripheral blood T lymphocytes: dependence on T-cell coreceptor and calcineurin signaling

The chemokine superfamily consists of small (8-10 kDa) molecules that function to attract, selectively, different subsets of leukocytes. Binding of chemokines to their appropriate G-protein-coupled receptors is necessary for primary immune responses and for homing of leukocytes to lymphoid tissues. Here, we have characterized the signaling pathways in primary T lymphocytes that regulate chemokine gene induction using an RNase protection assay. Dependence on stimulation through the coreceptor CD28 and sensitivity to the calcineurin inhibitors cyclosporine and tacrolimus were studied using purified human peripheral blood lymphocytes. Lymphotactin (Ltn), macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta were all rapidly induced and sensitive to cyclosporine treatment. At later time points, the expression of MIP-1alpha and MIP-1beta, but not of Ltn, was restored despite the inhibition of calcineurin activity. By contrast, the induction of interleukin-8 was delayed and was found to be cyclosporine insensitive. Calcineurin activity of IP-10 mRNA induction was contingent on the specific T-cell stimulation conditions, suggesting that IP-10 expression is modulated by calcineurin-dependent and -independent signaling pathways. Differential chemokine expression profiles result from the engagement of T-cell coreceptors and the requirement for, and the dependence on, calcineurin phosphatase activity.