Expression of Fas, FasL, and Soluble Fas mRNA in Endomyocardial Biopsies of Human Cardiac Allografts

FAS-670A＞G gene polymorphism and the risk of allograft rejection after organ transplantation: a systematic review and meta-analysis

The association between the risk of allograft rejection after organ transplantation and FAS gene polymorphism has been evaluated previously. However, inconsistent results have been reported. Hence, we conducted the most up-to-date meta-analysis to evaluate this association. All eligible studies reporting the association between FAS-670A＞G polymorphism and the risk of allograft rejection published up to December 2019 were extracted using a comprehensive systematic database search in the Web of Science, Scopus, and PubMed. The pooled odds ratios (OR) and corresponding 95% confidence intervals (CI) were calculated to determine the association strength. This meta-analysis included six case-control studies with 277 patients who experienced allograft rejection and 1,001 patients who did not experience allograft rejection (controls) after organ transplantation. The overall results showed no significant association between FAS-670A＞G polymorphism and the risk of allograft rejection in five genetic models (dominant model: OR=0.81, 95% CI=0.58‒1.12; recessive model: OR=0.10, 95% CI=0.80‒1.53; allelic model: OR=0.96, 95% CI=0.79‒1.18; GG vs. AA: OR=0.92, 95% CI=0.62‒1.36; and AG vs. AA: OR=0.75, 95% CI=0.52‒1.08). Moreover, subgroup analysis according to ethnicity and age did not reveal statistically significant results. Our findings suggest that FAS-670A＞G polymorphism is not associated with the risk of allograft rejection after organ transplantation.

Protective Effects of Apoptosis of Kupffer Cells Induced by Zoledronate Liposomes Following Hepatic Ischemia-Reperfusion Injury

Background

The goal of this study was to observe the effect of the apoptosis of Kupffer cells (KCs) selectively induced by zoledronate liposomes following the hepatic ischemia-reperfusion injury (IRI) in the rat liver transplantation model and to explore its mechanisms.

Material/Methods

The rat liver transplantation model was established using the improved Kamada method. Male Sprague Dawley rats were randomly divided into 3 groups: no liver transplantation or drug treatment (Group A); donor rats were injected with 1 mL normal saline through the tail vein for 3 continuous days before transplantation, and the donor liver was preserved in cold for 2 hours (Group B); donor rats were injected with 1 mL zoledronate liposomes (0.001 mg/mL) through the tail vein for 3 continuous days before transplantation, and the donor liver was preserved in cold for 2 hours (Group C). At 24 hours after transplantation, the receiving rats were sacrificed for sampling.

Results

Compared with Group C and Group A, the bile secretion flow was dramatically decreased in Group B, whereas the serum liver function index [alanine aminotransferase (ALT), glutamate aminotransferase (AST), and γ-glutamyl transpeptidase (γ-GT)] was significantly increased (P<0.01), and the pathological injury area was obviously increased. Compared with Group B, the levels of serum interleukin1 (IL-1), tumor necrosis factor-α (TNF-α), and the apoptotic index in Group C were significantly decreased (P<0.05), and Suzuki scores of congestion, vacuolar degeneration, and necrosis were all reduced (P<0.05).

Conclusions

The apoptosis of KCs selectively induced by zoledronate liposomes inhibited the inflammatory cascade reaction induced by KC activation and reduced the release of cytokines and decreased the extent of IRI in the liver transplantation in animal model.

Fas/Fas Ligand pathways gene polymorphisms in pediatric renal allograft rejection

BACKGROUND

An essential milestone in pediatric transplantation is to find noninvasive biomarkers to monitor acute rejection (AR). In this retrospective (Case-control) study, we examined the role of Fas -670A/G and Fas Ligand (FasL) -843C/T gene polymorphisms in allograft nephropathy in pediatric renal transplant recipients.

METHODS

In 47 pediatric kidney transplant recipients and 20 healthy controls, Fas -670A/G and FasL -843C/T gene polymorphisms as well as serum soluble Fas Ligand level (sFasL) were measured.

RESULTS

Serum sFasL levels were significantly higher in transplant recipients children than that in controls (548.25±298.64pg/ml vs 143.17±44.55pg/ml, p=0.0001). There was no significant difference between patients with AR and those without AR in regards to serum sFasL levels (567.70±279.87pg/ml vs 507.85±342.80pg/ml, p=0.56). Fas -670A/G genotypes or alleles were not significantly different between controls and transplant recipients and among transplant recipients with and without AR. (P>0.05 for all). FasL -843C/T genotypes were not different between transplant recipients and controls and among transplant recipients with and without AR (P>0.05 for all). However, Frequency of C allele in transplant patients was significantly higher than that in the control group (44.68% vs 25%, P=0.03). FasL -843C/T alleles were significantly different between patients with and without AR (P=0.03). The percentages of C allele were higher in children with AR (58.82% vs 36.67%). We found that serum FasL and serum creatinine were variables that were independently associated with AR.

CONCLUSION

This study suggests that FasL gene polymorphisms in peripheral blood might be accurate in detecting cellular AR.

Identification and classification of acute cardiac rejection by intragraft transcriptional profiling

BACKGROUND

Treatment of acute rejection (AR) in heart transplantation relies on histopathological grading of endomyocardial biopsies according to International Society for Heart and Lung Transplantation guidelines. Intragraft gene expression profiling may be a way to complement histological evaluation.

METHODS AND RESULTS

Transcriptional profiling was performed on 26 endomyocardial biopsies, and expression patterns were compared with the 1990 International Society for Heart and Lung Transplantation AR grades. Importantly, transcriptional profiles from settings with an equivalent AR grade appeared the same. In addition, grade 0 profiles could not be distinguished from 1A profiles, and grade 3A profiles could not be distinguished from 3B profiles. Comparing the AR groupings (0+1A, 1B, and 3A+3B), 0+1A showed more striking differences from 1B than from 3A+3B. When these findings were extrapolated to the 2005 revised guidelines, the combination of 1A and 1B into a single category (1R) appears to have brought together endomyocardial biopsies with different underlying processes that are not evident from histological evaluation. Grade 1B was associated with upregulated immune response genes, as 1 categorical distinction from grade 1A. Although grade 1B was distinct from the clinically relevant AR grades 3A and 3B, all of these grades shared a small number of overlapping pathways consistent with common physiological underpinnings.

CONCLUSION

The gene expression similarities and differences identified here in different AR settings have the potential to revise the clinical perspective on acute graft rejection, pending the results of larger studies.

Apoptosis and acute cellular rejection in human heart transplants

INTRODUCTION AND OBJECTIVES

Apoptosis has been implicated in the pathophysiology of various forms of heart disease. Acute cellular rejection leads to morbidity after heart transplantation and invasive techniques are needed for its diagnosis. We investigated the presence of cardiomyocyte apoptosis in transplanted hearts, its progression, its relationship with rejection, and the possibility that serological markers of apoptosis can be used to detect rejection noninvasively.

METHODS

Overall, 130 endomyocardial biopsies obtained sequentially from 14 consecutive patients during the first 6 months following heart transplantation underwent histochemical analysis. The degree of acute rejection was determined, myocyte apoptosis was assessed using the TUNEL method, and caspase-3 activity was measured. In the first 10 patients, soluble Fas, tumor necrosis factor-alpha (TNFα) and interleukin 6 levels were determined in serum collected at biopsy.

RESULTS

Apoptotic cells were detected in 81.5% of biopsies. No significant correlation was found between the apoptotic index and either the degree of rejection or the time from transplantation; there was only a trend to higher values during prolonged episodes of rejection, which did not reach statistical significance. An inverse correlation was observed between the degree of rejection and the TNFα level (rs=-0.33; P=.003). There was no correlation with any other variable.

CONCLUSIONS

Cardiomyocyte loss due to apoptosis was observed in transplanted hearts, but no correlation was observed with either acute rejection or the time from transplantation. Our findings suggest there could be an inverse correlation between rejection and the serum TNFα level. No serum parameter evaluated was regarded as suitable for the noninvasive diagnosis of acute rejection.

Whole blood biomarkers of acute cardiac allograft rejection: double-crossing the biopsy

BACKGROUND

Acute rejection is still a significant barrier to long-term survival of the allograft. Current acute rejection diagnostic methods are not specific enough or are invasive. There have been a number of studies that have explored the blood or the biopsy to discover genomic biomarkers of acute rejection; however, none of the studies to date have used both.

METHODS

We analyzed endomyocardial biopsy tissue and whole blood-derived messenger RNA from 11 acute rejection and 20 nonrejection patients using Affymetrix Human Genome U133 Plus 2.0 chips. We used a novel approach and gained insight into the biology of rejection based on gene expression in the biopsy, and applied this knowledge to the blood analysis to identify novel blood biomarkers.

RESULTS

We identified probesets that are differentially expressed between acute rejection and nonrejection patients in the biopsy and blood, and developed three biomarker panels: (1) based on biopsy-only (area under the curve=0.85), (2) based on biopsy-targeted whole blood (area under the curve=0.83), and (3) based on whole blood-only (area under the curve=0.60) analyses.

CONCLUSIONS

Most of the probesets replicated between biopsy and blood are regulated in opposite direction between the two sources of information. We also observed that the biopsy-targeted blood biomarker discovery approach can improve performance of the biomarker panel. The biomarker panel developed using this targeted approach is able to diagnose acute cardiac allograft rejection almost as well as the biopsy-only based biomarker panel.

The role of FasL and Fas in health and disease

The FS7-associated cell surface antigen (Fas, also named CD95, APO-1 or TNFRSF6) attracted considerable interest in the field of apoptosis research since its discovery in 1989. The groups of Shin Yonehara and Peter Krammer were the first reporting extensive apoptotic cell death induction upon treating cells with Fas-specific monoclonal antibodies.1,2 Cloning of Fas3 and its ligand,4,5 FasL (also known as CD178, CD95L or TNFSF6), laid the cornerstone in establishing this receptor-ligand system as a central regulator of apoptosis in mammals. Therapeutic exploitation of FasL-Fas-mediated cytotoxicity was soon an ambitous goal and during the last decade numerous strategies have been developed for its realization. In this chapter, we will briefly introduce essential general aspects of the FasL-Fas system before reviewing its physiological and pathophysiological relevance. Finally, FasL-Fas-related therapeutic tools and concepts will be addressed.

Clinical impact of cytokine and growth factor genetic polymorphisms in thoracic organ transplantation

Demographic and clinical risk factors may only partially predict short- and long-term outcomes after thoracic transplantation. The interindividual variability seen in rejection profiles could be related to the recipient's or donor's genetic background. Rejection, either acute or chronic, elicits an alloimmune response that involves a complex network of cytokines, growth factors, adhesion molecules, and other molecules, which may modulate the immune response toward rejection or, conversely, mediate graft acceptance. Herein, the authors discuss the current evidence regarding the importance of genetic polymorphisms as independent predictors of allograft outcome. They believe that pretransplant genotype profiling of patients, in combination with other relevant clinical information, might be useful to predict the risk for posttransplant adverse events and also to facilitate the implementation of individualized immunosuppression.