Blood levels of TGFbeta1 in liver transplant recipients receiving either tacrolimus or micro-emulsified cyclosporine

Transforming growth factor β1 polymorphisms and progression of graft fibrosis after liver transplantation for hepatitis C virus--induced liver disease

Re-infection with the hepatitis C virus (HCV) is an important development after liver transplantation (LT); it can lead to graft fibrosis. The aim of this study was to assess the role of transforming growth factor β1 (TGF-β1) polymorphisms in the development of HCV-related graft disease by evaluating protocol liver biopsies. A total of 192 patients with a recurrence of HCV infection after LT were genotyped for TGF-β1 codon 10 (C→T) and codon 25 (G→C) using the polymerase chain reaction. Histological evaluation of 614 protocol liver biopsies obtained from these patients was undertaken using the classification of Desmet and Scheuer to stage the degree of fibrosis. Mild stages of fibrosis (0-2) were compared to advanced stages of fibrosis (3-4) that developed during the period of infection with the virus. Correlations between the prevalence of TGF-β1 genotypes and the different degrees of fibrosis that developed were determined. No statistically significant differences were found for genotype distributions (codons 10 and 25) with respect to recipient age, donor sex, occurrence of acute cellular rejection, and response to antiviral therapy. However, the C allele at codon 25 was significantly less frequent in the group with advanced fibrosis (P = 0.001). Furthermore, a positive association was found between progression of fibrosis and male recipient sex (P = 0.024), donor age (P = 0.041), and viral genotype 1b (P = 0.002). In conclusion, this study, in which the evolution of hepatic fibrosis was assessed histologically in a large cohort of patients with HCV re-infection after LT, has demonstrated that the C allele at codon 25 of the TGF-β1 gene is a marker for the development of graft fibrosis.

Early expression of hepatocyte growth factor, interleukin-6, and transforming growth factor-beta1 and -beta2 in symptomatic infection in patients who have undergone liver transplantation

INTRODUCTION

Early septic complications may be a deciding factor for successful recovery among patients who have undergone orthotopic liver transplantation. Therefore, monitoring liver function parameters plays an important role in postoperative treatment to achieve an early diagnosis of postsurgical complications. We ought to measure standard liver function parameters and the expression levels for selected cytokines among patients exhibiting symptoms of infection after orthotopic liver transplantation.

MATERIALS AND METHODS

The study was performed on 30 patients who were divided into two groups: SI-0 consisted of patients free of infection, and SI-1, those who had symptoms of infection. We determined standard liver function parameters and expression of hepatocyte growth factor (HGF), interleukin (IL)-6, transforming growth factor (TGF)-beta1, and TGF-beta2.

RESULTS

There were no significant differences in standard liver function parameters between the two groups of patients. There were no significant differences in the levels of expression for the cytokines in question between the two groups of patients.

CONCLUSIONS

Although standard liver function parameters provide diagnostically valuable information on the patient's condition, they cannot be used to determine the extent of systemic infection among patients showing signs of infection after liver transplantation. Determining gene expression levels in circulating lymphocytes is a sensitive method to monitor patients' condition after liver transplantation. The expression levels of HGF, IL-6, TGF-beta1, and TGF-beta2 in circulating lymphocytes were not sufficiently specific to diagnose transitory postsurgical complications such as symptomatic infection.

Transforming growth factor-beta1 gene expression and cyclosporine A-induced gingival overgrowth: a pilot study

AIMS

The relationship between gingival overgrowth (GO) induced by cyclosporine A (CsA) and transforming growth factor-beta1 (TGF-beta1) remains unclear. The aims of the present study were to evaluate TGF-beta1 gene expression under different immunosuppressive treatments and its association with TGF-beta1 gene functional polymorphism and GO in renal transplant recipients.

MATERIAL AND METHODS

The study included 98 CsA-treated renal transplant recipients (with and without GO) and 44 tacrolimus-treated transplant patients (without GO). TGF-beta1 mRNA expression was measured using a real-time quantitative polymerase chain reaction assay. The levels were correlated with TGF-beta1 gene polymorphisms at codons 10 and 25, with different immunosuppressive treatment and GO.

RESULTS

The level of TGF-beta1 gene expression was insignificantly lower in the CsA-treated group compared with the tacrolimus group, and significantly lower in the group with GO compared with patients without GO. In tacrolimus- and CsA-treated patients, but not in patients with GO, the level of TGF-beta1 gene expression was associated with functional phenotypes of TGF-beta1. The incidence, degree and extent of GO were higher in recipients with lower TGF-beta1 gene expression.

CONCLUSIONS

Lower level TGF-beta1 gene expression, not functional polymorphism, in patients treated with CsA may be considered to be a risk factor for GO.

Effects of different immunosuppressive regimens on regulatory T-cells in noninflamed colon of liver transplant recipients

BACKGROUND

Regulatory T-cells (Treg) are natural suppressors of autoimmunity. Previous studies indicate that immunosuppressive drugs, especially calcineurin-inhibitors, may interfere with Treg homeostasis. Inflammatory bowel disease (IBD) can relapse or develop de novo after liver transplantation. IBD is associated with a relative deficiency of Treg. The aim of this study was to determine the effect of long-term immunosuppression on the presence of Treg in the noninflamed colonic mucosa of liver transplant recipients.

METHODS

Colonic biopsies of normal mucosa of 36 liver transplant recipients on different types of immunosuppression and 11 controls were studied. Treg marker Foxp3 and Treg products transforming growth factor-beta (TGF-beta) and interleukin-10 (IL-10) were studied by quantitative polymerase chain reaction (Q-PCR) and immunohistochemistry. TGF-beta-induced Smad-protein 3 and 7 were studied by Q-PCR.

RESULTS

No significant differences between controls and patients were observed in IL-10, TGF-beta, and Smad expression. Mucosal Foxp3 mRNA levels and Foxp3+CD3+ cells were significantly reduced in transplant recipients using prednisone/azathioprine/tacrolimus compared with controls but no direct relationship between Foxp3 expression and 1 specific drug was detected.

CONCLUSIONS

These results challenge the hypothesis that calcineurin-induced reduction of Treg or TGF-beta expression predisposes nontransplanted tissue to inflammation, but indicate that combined immunosuppression hampers Treg development in the intestine.

Concentrations of cyclosporin A and FK506 that inhibit IL-2 induction in human T cells do not affect TGF-beta1 biosynthesis, whereas higher doses of cyclosporin A trigger apoptosis and release of preformed TGF-beta1

Cyclosporin A (CsA) and FK506 suppress T cell activation by inhibiting calcineurin and the calcineurin-dependent transcription factors nuclear factor of activated T cells (NFATc), which are central regulators of T cell function. It was reported that CsA up-regulated the transcription of transforming growth factor-beta1 (TGF-beta1) in lymphocytes and other cells and activated its promoter in A549 lung carcinoma cells, but the mechanisms involved are poorly understood, and it is unclear whether calcineurin plays any role. We have studied the regulation of TGF-beta1 in normal human lymphocytes and cell lines. In Jurkat T cells, the TGF-beta1 promoter was activated by calcineurin and NFATc and inhibited by CsA and FK506. However, the promoter was insensitive to both drugs in A549 cells. In human T cells preactivated with phytohemagglutinin, biosynthesis of TGF-beta1, induced by the T cell receptor (TCR) or the TGF-beta receptor, was not substantially affected by CsA and FK506 concentrations (< or = 1 microM) that effectively inhibited interleukin-2 production. However, pretreatment of fresh lymphocytes with CsA or FK506 during primary TCR stimulation reduced their production of TGF-beta1 during secondary TCR activation. Finally, high concentrations of CsA (10 microM), in the range attained in vivo in experiments in rodents, caused apoptosis in human T cells and the release of preformed, bioactive TGF-beta1. These effects are unlikely to owe to calcineurin inhibition, as they were not observed with FK506. Our results indicate that CsA and FK506 are not general inducers of TGF-beta1 biosynthesis but can cause different effects on TGF-beta1 depending on the cell type and concentrations used.

Plasma TGF-beta1 as a risk factor for gingival overgrowth

BACKGROUND AND AIMS

Induction of the pro-fibrotic growth factor TGF-beta1 has been suggested as a possible mechanism through which immunosuppressant drugs may induce gingival overgrowth. This study aims to investigate plasma levels of TGF-beta1 and relate them to the development and severity of gingival overgrowth in immunosuppressed transplant patients.

MATERIALS AND METHODS

One hundred and thirty-two ciclosporin-treated and 13 tacrolimus-treated transplant patients and 24 drug-free control subjects underwent a full periodontal examination including a determination of the presence and severity of gingival overgrowth.

RESULTS

Plasma TGF-beta1 concentrations were determined by ELISA, and were found to be significantly elevated in samples from the transplant patients (mean=29.1 ng/ml) as compared with controls (mean=6.1 ng/ml, p<0.0001). There was no significant difference between the levels of plasma TGF-beta1 in the ciclosporin- and tacrolimus-treated patient groups.

CONCLUSIONS

Furthermore, concomitant treatment with calcium channel blockers did not influence the levels of plasma TGF-beta1 in the patients group. The relationship between gingival overgrowth, independent periodontal variables and TGF-beta1 plasma concentrations was examined using univariate and multivariate regression analyses; low TGF-beta1 plasma concentrations were found to be a risk factor for gingival overgrowth in immunosuppressed patients concomitantly receiving a calcium channel blocker.

Influence of Th1, Th2, and Th3 cytokines during the early phase after liver transplantation

To investigate the change of Th1, Th2, Th3 cytokines during early liver transplantation. IFN-r, IL-4, TGF-beta production by CD4+ T cells were determined by fluorescence activated cell sorter analysis. Comparing the acute rejection with the non-acute rejection groups on the 7th, 14th, and 28th day showed that high interferon-gamma production associated with acute rejection in the early posttransplant period. There was no evidence of significant changes in interleukin-4 and transforming growth factor beta (TGF-beta) levels between non-acute rejection groups with acute rejection groups. Th1 cytokine high production is significantly associated with acute rejection in liver transplant recipients.

Tacrolimus has less fibrogenic potential than cyclosporin A in a model of renal ischaemia-reperfusion injury

BACKGROUND

Cyclosporin is associated with significant chronic nephrotoxicity, manifest in the long term mainly as renal fibrosis. There have been claims that tacrolimus is a less fibrotic drug than cyclosporin, and this study was designed to determine the effect of the two drugs on the expression of fibrosis-associated genes.

METHODS

Male Wistar rats underwent clamping of the right renal pedicle for 45 min together with left nephrectomy; this model has previously been shown to be associated with upregulation of fibrosis-associated genes. Experimental groups (six animals per group) received cyclosporin A 10 mg/kg daily, tacrolimus 0.2 mg/kg daily or no treatment. Animals were killed at 16 weeks, and the renal cortical expression of fibrosis-associated genes was studied by means of quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Tacrolimus-treated animals developed significantly less proteinuria and had lower serum creatinine levels than those receiving cyclosporin. Tacrolimus administration also significantly reduced the expression of transforming growth factor beta and tissue inhibitor of metalloproteinases 1, both the products of genes associated with fibrosis. Although cyclosporin treatment reduced levels of the matrix-degrading enzymes, matrix metalloproteinase (MMP) 2 and MMP-9, this was not statistically significant.

CONCLUSION

Tacrolimus has less nephrotoxicity than cyclosporin in this model. It also appears to have less fibrogenic potential, and this may have implications for the choice of long-term immunosuppressant in renal transplantation.