Pyrosequencing to identify homogeneous phenomenon when using recipients/donors with different CYP3A5*3 genotypes in living donor liver transplantation. PLoS One. 2013;8:e71314. [PMID: 23951129 DOI: 10.1371/journal.pone.0071314]

Liver Graft Pathology and Low Serum 25-Hydroxyvitamin D after Living Donor Liver Transplantation

BACKGROUND

Most cases of advanced liver diseases are associated with low serum 25-hydroxyvitamin D and vitamin D deficiency. This phenomenon may occur in living donor liver transplantation (LDLT).

AIMS

We conducted this study to explore the interplay between VDR and CYP2R1 in liver graft and compared our findings with the pathological interpretation of serum 25(OH)D concentration.

METHODS

In total, 60 patients received liver graft biopsy after LDLT and were separated (1:1) into two groups: graft rejection group and graft non-rejection group. We extracted both of the recipients' and donors' serum DNA to investigate the vitamin D receptor (VDR) rs2228530 and CYP2R1 rs10741657 single nucleotide polymorphisms (SNPs) using real-time polymerase chain reaction. We also extracted DNA from liver graft tissues to explore the genetic alleles of VDR rs2228530 and CYP2R1 rs10741657 after LDLT. Serum biochemistry profile and 25(OH)D concentrations were measured before and after LDLT.

RESULTS

There were no significant differences in serum VDR rs2228530 and CYP2R1 rs10741657 genetic alleles between recipients and donors. The percentage of genetic modification was 33.4% (10/30) for the rejection and non-rejection groups in VDR rs2228530, and 66.7% (20/30) for both groups in CYP2R1 rs10741657. Serum 25(OH)D concentrations were significantly lower after LDLT D30 than that before LDLT in the rejection (p = 0.0001) and non-rejection graft pathology (p = 0.0017) groups.

CONCLUSIONS

The presence of low serum 25(OH)D concentrations after LDLT suggested that post-transplant low serum 25(OH)D concentrations may develop with the homogenous phenomenon of VDR rs2228530 and CYP2R1 rs10741657 genetic modifications in recipients regardless of graft pathology.

Effects of donor-recipient combinational CYP3A5 genotypes on tacrolimus dosing in Chinese DDLT adult recipients

BACKGROUND

For liver transplant (LT) recipients, the liver CYP3A5 metabolic enzymes are determined by the donor's genes, whereas the intestinal enzymes are encoded by the recipient's genes. This combinational form confuses the metabolism of tacrolimus (Tac) in vivo. This retrospective study was conducted to investigate the combined effects of donor-recipient CYP3A5 genotype on tacrolimus pharmacokinetics in Chinese LT adult patients.

METHODS

Three hundred seventy-three LT patients from two Chinese organ transplant centers were enrolled, and both recipients and donors were genotyped for CYP3A5. Patients were divided into four groups (R_ND_N, R_ED_N, R_ND_E, R_ED_E) according to CYP3A5*3 allele expressers (E) and non-expressers (N) in recipients (R) and donors (D). The dose-adjusted trough levels (C/D ratio) of tacrolimus were assessed for six months among the four groups. Multiple linear regression analysis was performed to assess the effects of the CYP3A5 genotype and several clinical variables on the C/D ratio.

RESULTS

The R_ND_N group consistently had the largest C/D ratio throughout the entire study period, whereas the R_ED_E group had the smallest C/D ratio, and the R_ED_N/R_ND_E group had an intermediate (R_ND_N > R_ED_N/R_ND_E > R_ED_E) ratio. The C/D ratio in the R_ND_N and R_ND_E groups was higher than that in the R_ED_N and R_ED_E groups within three months, respectively; the ratio in the R_ND_N group was higher than that in the R_ND_E group, and the ratio in the R_ED_N group was higher than that in the R_ED_E group at six months. The effect of the donor CYP3A5 genotype on C/D values was observed throughout the timeline, and the recipient's genetics correlated only in the first three months. Among non-genetic factors, hemoglobin (HGB) and albumin (ALB) were correlated with Tac C/D values at a few time points.

CONCLUSIONS

To predict the initial dose of tacrolimus in LT patients, both donor and recipient CYP3A5 genotypes must be taken into account; during the maintenance phase of targeted blood concentration, the donor's CYP3A5 genotype may be of prime importance, especially at three months after transplantation.

The Genotype Frequency of CYP2C19 Enzyme after Liver Transplantation

BACKGROUND

Liver transplant recipients are treated with various drugs, the metabolism of which is dependent on the cytochrome P450 polymorphic genotype.

OBJECTIVE

To identify the polymorphic variety of CYP2C19 genotype in liver allograft before and after transplantation.

METHODS

The study was conducted on 88 liver recipients. The CYP2C19 genotypes in donors and recipients were the same in 32 and different in 56 recipients. Extracted genomic DNA from the leukocytes and liver graft tissues were analyzed by TaqMan SNP genotyping assay. The distributions of homozygote, heterozygote, poor and ultra-rapid metabolizers' genotypes were investigated in both groups.

RESULTS

The distributions of CYP2C19 genotypes before transplantation in the blood and liver graft were within the normal range. After transplantation, in patients with different CYP2C19 genotype in donors and recipients, the genotypes of homozygote and ultra-rapid metabolizers were significantly decreased (p=0.024); the heterozygotes and poor metabolizer genotypes were significantly increased (p=0.017).

CONCLUSION

The variety in CYP2C19 genotyping must be considered in patients with different genotypes in donor and recipients to predict the dosage regimens, optimize the treatment and decrease toxicity.

Recipient ABCB1, donor and recipient CYP3A5 genotypes influence tacrolimus pharmacokinetics in liver transplant cases

BACKGROUND

Effective immunosuppression through optimization of trough levels tacrolimus reduces post-transplant mortality rate in liver transplant cases.

METHODS

Meta-analysis was carried out to evaluate how donor/recipient CYP3A5 (n = 678) and recipient ABCB1 (n = 318) genotypes influence tacrolimus pharmacokinetics till one-month of transplantation.

RESULTS

The donor CYP3A5*3/*3 genotype exhibited higher concentration/dose (C/D) ratio of tacrolimus in week 1 (mean difference: 65.04, 95% CI: 15.30-114.79 ng/ml/mg/kg), week 2 (mean difference: 21.7, 95% CI: 12.6-30.9 ng/ml/mg/kg) and week 4 (mean difference: 43.28, 95% CI: 17.09 - 69.49 ng/ml/mg/kg) compared to *1/*1 and *1/*3 genotypes. The recipient CYP3A5 *3/*3 genotype did not showed significant difference in tacrolimus C/D ratio in week 1 compared to other two genotypes. However, week 2 (mean difference: 44.16, 95% CI: 3.68-84.65 ng/ml/mg/kg) and week 4 (mean difference: 43.74, 95% CI: 12.50-75.00 ng/ml/mg/kg) availability was higher in *3/*3 mutant recipients. However, the recipient ABCB1 3435 C > T polymorphism has no significant influence on tacrolimus pharmacokinetics till one month of transplant.

CONCLUSIONS

The donor and recipient CYP3A5*3 polymorphism influences tacrolimus pharmacokinetics in the first month post-transplantation, whereas the association with recipient ABCB1 3435 C > T is inconclusive.

Genetic polymorphisms of the hepatic pathways of fatty liver disease after living donor liver transplantation

BACKGROUND & AIMS

Fatty liver disease is an important complication associated with liver transplantation, and the cytochrome P-450 system of the donor liver may be involved in its pathogenesis. To explore the effects of the CYP27A1, CYP27B1, CYP2R1, and vitamin D receptor pathways on vitamin D maintenance after living donor liver transplantation, we investigated the interplay between serum 25(OH)D and common variants in 60 paired donors and recipients who underwent living donor liver transplantation.

METHODS

We prospectively collected 60 donor/recipient pairs from our liver transplantation programmes and extracted serum DNA to evaluate single nucleotide polymorphisms in CYP27A1 rs4674344, CYP27B1 rs10877012, CYP2R1 rs10741657, and VDR rs2228530 alleles using real-time polymerase chain reaction. We measured serum 25(OH)D concentrations of donors (D-D0) and recipients before (R-D0) and after (R-D30) living donor liver transplantation for comparison with repeated-measures analysis of variance in generalized estimating equations analysis.

RESULTS

Fatty liver disease was noted in 28.3% of the cases after living donor liver transplantation, and the graft rejection rate was 25%. There were significant differences in low serum 25(OH)D concentrations between D-D0 and R-D0 and between R-D0 and R-30 groups. Significant associations were observed for serum CYP27A1 rs4674344 in recipients and donors as well as for graft liver tissue with VDR rs2228530. There was no significant relationship with serum CYP27B1 rs10877012 in recipients and donors or with graft liver tissue with CYP2R1 rs10741657.

CONCLUSIONS

Donor/recipient CYP27A1 rs4674344 and graft VDR rs2228570 may be related to low serum 25(OH)D and may play a major role in the development of fatty liver disease in recipients after living donor liver transplantation.

Association between Subclinical Low Serum 25(OH)D in Donors and Fatty Liver Disease in Recipients after Living Donor Liver Transplantation

To explore subclinical fatty liver disease (FLD) in donors as a possible mechanism leading to FLD in recipients of living donor liver transplantation (LDLT), we extracted thirty donor-recipient pairs' serum DNA and explored the presence of CYP2R1 single nucleotide polymorphism (SNP) rs10741657 and vitamin D receptor (VDR) SNP rs2228530 A/G alleles using real-time polymerase chain reaction. We measured the serum 25(OH)D concentrations and investigated the CYP2R1 and VDR genotypes of the donors and recipients before and after LDLT for comparison with the histological findings from the donors on wedge biopsy, the recipients' removed native liver, and selective liver biopsy after LDLT. There was a significant difference in low serum 25(OH)D concentration between the donors and recipients before LDLT and in the recipients before versus after LDLT (13.90 ± 8.85 versus 47.9 ± 14.88 versus 11.82 ± 10.36, P < 0.001), and significant difference in FLD was detected on wedge biopsy from the donors and the native liver from the recipients as well as the native liver and follow-up biopsy from the recipients (P < 0.001). CYP2R1 and VDR genotype were predominant, both for the AG and for the GG alleles. For the donor VDR SNP rs2228570, low serum 25(OH)D was significantly different between genotypes AA and AG (P = 0.024) as well as between genotypes AA and AG plus GG (P = 0.042). Our data suggest that donors' VDR rs2228570 AA alleles may play a major role in low serum 25(OH)D regarding pathological FLD in recipients after LDLT.

Association of IL28B SNPs rs12979860 and rs8099917 on Hepatitis C Virus-RNA Status in Donors/Recipients of Living Donor Liver Transplantation

To investigate the effect of IL28B single nucleotide polymorphisms (SNPs) (rs8099917 and rs12979860) in the donors and recipients on the outcome of Hepatitis C virus-RNA clearance after living donor liver transplantation (LDLT). The rs8099917 and rs12979860 genotypes in 50 donor and recipients pairs were explored on the pre-operative day (POD) and post-operative day 30 (POD30). There was a significant difference in HCV-RNA clearance before (12%, 6/50) and after (48%, 24/50) liver transplantation (P < 0.001). The rs8099917 genotype TT was dominant in both the recipients (82%, 41/50) and donors (86%, 43/50), but had no significant effect on HCV-RNA clearance (87.5%, 21/24) and recurrence (76.9%, 20/26) after LDLT. One recipient was detected with genotype GG on POD, which changed to genotype GT on POD30. Prevalence of rs12979860 genotype CT was 98% (49/50 recipient) and 92% (46/50 donor) and prevalence of genotype CC was 2% (1/50 recipient) and 8% (4/50 donor) on POD and POD30, respectively. Of the 4 recipients with rs12979860 genotype CC on POD30, 3 recipients (12.5%, 3/24) exhibited HCV clearance and 1 experienced recurrence (3.9%, 1/26), however, this was not statistically significant. In conclusion, alterations in IL28B SNP genotype may occur after LDLT, leading to modifications in the host genome or donor proteome by HCV. This predicted mechanism will need to be investigated further.

Repeated-measures implication of hepatocellular carcinoma biomarkers in living donor liver transplantation

Objective

Hepatocellular carcinoma (HCC) and its recurrence are major problems in living donor liver transplantation (LDLT). Several biomarkers have been used to investigate this event. We conducted a prospective controlled study to determine the activities of the basic fibroblast growth factor (FGF-2), survivin, Ki67, endostatin, and vascular endothelial growth factor (VEGF) in different conditions before, early after, and late after LDLT with and without HCC recurrence.

Methods

Fifty patients with virus-related HCC who underwent LDLT were enrolled in this 2-year cross-sectional study. During the study period, recurrent HCC was identified in 9 patients (study group, n = 9) and 41 patients (control group, n = 41) had no recurrence after LDLT. The mean time to HCC recurrence was 587.11 ± 398.64 days (range, 90–1352 days). Microvascular invasion (MVI) was found in 66.7% (6/9) of the recipients, as determined on pathological examination. The serum biomarkers were investigated by using enzyme-linked immunosorbent assay at the different LDLT stages.

Results

The serum levels of the biomarkers significantly correlated with LDLT and HCC recurrence in the repeated-measures analysis (F = 31.676, P = 0.000). Significant differences were observed in the effects of all biomarkers (F = 85.313, P = 0.000) and the time to HCC recurrence after LDLT (F = 3.178, P = 0.046). The biomarkers, ordered by the observed power of the test for HCC recurrence after LDLT, were FGF-2 (1.000) > survivin (0.999) > Ki67 (0.949) > endostatin (0.411) > VEGF (0.305).

Conclusions

Different biomarker activities may be implicated in the pathogenesis of HCC recurrence after LDLT. Oncogenes may not exist in the new graft but may still be present in the peripheral blood. The timing of HCC recurrence and impact of MVI in the explanted liver requires confirmation in larger studies with a longer follow-up.

Cytochrome P450 in living donor liver transplantation

Cytochrome P450 metabolizes many drugs in the liver. Three genotypes of CYP2C19 with extensive, intermediate, and poor metabolizing activity, respectively, have been identified in peripheral blood of transplant recipients and new liver grafts in living donor liver transplantation (LDLT). The expression of the final genotype in liver graft biopsies depends on the donor, whereas the expression in peripheral blood mononuclear cells depends on the recipient. The metabolizing isoenzyme of the major anti-rejection agents passes through CYP3A4, CYP3A5 and MDR1, which have also been identified to have similar biological characteristics as genotype of CYP2C19 in liver tissue. Recently, pyrosequencing has been used to investigate the expressions of different genotypes in liver grafts in LDLT. This review focuses on recent findings regarding the biological expressions of the CYP2C19, CYP3A4, CYP3A5 and MRD1 genotypes in liver grafts before and after LDLT. The application of pyrosequencing may be beneficial in further research on liver transplantation. Laser capture microdissection of hepatocytes in liver grafts may be a direction for future research.

Homogeneous phenomenon of the graft when using different genotype characteristic of recipients/donors in living donor liver transplantation

AIM: To investigate the evidence of homogeneous phenomenon on CYP3A5*3 MDR1-3435 and CYP3A4*18 of the liver graft after living donor liver transplantation (LDLT).

METHODS: We identified the proportional change of the CYP3A5*3, MDR1-3435 and CYP3A4*18 from the peripheral blood mononuclear cell of 41 pairs recipient/donor with different genotype polymorphisms and 119 liver graft biopsy samples used with the pyrosequencing technique after LDLT. Polymerase chain reaction/ligase detection reaction assay and restriction fragment length polymorphism was employed for genotyping the CYP3A5*3 and CYP3A4*18 single nucleotide polymorphisms (SNPs). All of the recipients and donors expressed with the similar SNP genotype of CYP3A5*3, MDR1-3435 or CYP3A4*18 were excluded.

RESULTS: The final genetic polymorphisms of the liver graft biopsy samples of CYP3A5*3, MDR1-3435 and CYP3A4*18 was predominated depends on the donor with restriction fragment length polymorphism and seems to be less related to the recipient. The proportional changes of G to A alleles of the 119 samples of CYP3A5*3 (included A > A/G, A/G > A, A/G > G, G > A, G > A/G and A > G), C to T alleles of the 108 samples of MDR1-3435 (included C > C/T, C/T > C, C/T > T, T > C/T and T > C), and T to C alleles of 15 samples of CYP3A4*18 (included T/C > T and T > C/T) were significant different between the recipients and the liver graft biopsy samples (P < 0.0001) and less difference when compared with the donors in the pyrosequencing analysis after LDLT.

CONCLUSION: The CYP3A5*3, MDR1-3435 and CYP3A4*18 of the recipient could be modified by the donor so-called homogenous phenomenon when the recipient’s blood drained into the liver graft.