Novel single nucleotide polymorphisms in interleukin 6 affect tacrolimus metabolism in liver transplant patients

Impact of CYP2D6*2A, CYP2D6*4 and CYP3A5*3 genetic polymorphisms on Bisoprolol peak concentration and clinical response in acute coronary syndrome patients

AIMS

Acute coronary syndrome (ACS) represents a major cause of death. Bisoprolol is commonly used in the management of ACS. This study aims to investigate the impact of CYP2D6*2A, CYP2D6*4 and CYP3A5*3 genetic polymorphisms on pharmacokinetics and clinical response of bisoprolol in ACS patients.

METHODS

This is an open-label cohort study that included 127 ACS patients and studied the effect of CYP3A5*3, CYP2D6*2A and CYP2D6*4 genotyping using real-time polymerase chain reaction on steady state bisoprolol plasma peak concentration analysed by high performance liquid chromatography-fluorescence detector.

RESULTS

Regarding CYP3A5*3, the mean peak bisoprolol concentration for CC, CT and TT genotypes were 4.25 ± 1.20, 3.93 ± 1.10 and 1.79 ± 0.69 ng/mL, respectively (P < .001). Higher systolic (126 ± 5.47 mmHg), diastolic blood pressure (82 ± 2.73 mmHg) and heart rate (97.80 ± 3.03 beats/min) were also observed in CYP3A5*3 TT carriers (P < .05). In CYP2D6*2A, the peak concentration of bisoprolol was lower in CC carriers (3.54 ± 1 ng/mL) compared to GG (4.38 ± 1.25 ng/mL) and GC carriers (4.07 ± 1.29 ng/mL, P = .019). In CYP2D6*4, the mean bisoprolol peak concentration in CC carriers was 3.98 ± 1.31 ng/mL, which was lower than T allele carriers (4.5 ± 0.8, P = .02). No differences in heart rate, systolic, diastolic blood pressure or bisoprolol dose were observed among CYP2D6*2A or CYP2D6*4 variants. Smokers exhibited lower bisoprolol peak concentration (3.96 ± 1.2 ng/mL) compared to nonsmokers (4.55 ± 1.34 ng/mL, P = .037).

CONCLUSION

There is an association between CYP3A5*3, CYP2D6*4, CYP2D6*2A variants and bisoprolol peak concentration, which may serve as a guide in the future in choosing the optimum dose of bisoprolol in ACS patients.

UHPLC-MS/MS method for the determination of azithromycin in human plasma of pediatric patients

The determination of azithromycin in human plasma of pediatric patients was performed with a ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay. A simple sample preparation of protein precipitation was used and the separation was achieved on a C18 column by the gradient mixture of mobile phase A ( 0.1% acetic acid and 3 mM ammonium acetate in water) and the mobile phase B (0.1% acetic acid and 3 mM ammonium acetate in the solution of acetonitrile, methanol and water, 47.5/47.5/5, V/V/V). The multiple reaction monitoring (MRM) mode was adopted to monitor the precursor-to-product ion transitions of m/z 749.6→m/z 591.5 for azithromycin and m/z 753.6→m/z 595.5 for azithromycin-¹³ C-d3 (IS) at positive ionization mode. The calibration curve ranged between 0.5 ng·mL^-1 and 500.0 ng·mL^-1 and the correlation coefficient was greater than 0.99. The intra- and inter-batch precision was less than 13.7%. Accuracy determined at four concentrations ranged from 99.5% to 110.8%. The extraction recoveries were more than 95% and the matrix effects were 98% - 100%. The stability under various conditions were acceptable with the accuracy deviation within 9.2%. In conclusion, our method was simple, sensitive and reliable for quantification of azithromycin in plasma among pediatric patients.

Towards next-generation personalization of tacrolimus treatment: a review on advanced diagnostic and therapeutic approaches

The benefit of personalized medicine is that it allows the customization of drug therapy - maximizing efficacy while avoiding side effects. Genetic polymorphisms are one of the major contributors to interindividual variability. Currently, the only gold standard for applying personalized medicine is dose titration. Because of technological advancements, converting genotypic data into an optimum dose has become easier than in earlier years. However, for many medications, determining a personalized dose may be difficult, leading to a trial-and-error method. On the other hand, the technologically oriented pharmaceutical industry has a plethora of smart drug delivery methods that are underutilized in customized medicine. This article elaborates the genetic polymorphisms of tacrolimus as case study, and extensively covers the diagnostic and therapeutic technologies which aid in the delivery of personalized tacrolimus treatment for better clinical outcomes, thereby providing a new strategy for implementing personalized medicine.

Single nucleotide polymorphisms in interleukin-6 attenuates hepatocytes injury in hypoxia/re-oxygenation via STAT3 signal pathway mediated autophagy

Ischemia-reperfusion injury (IRI) is inevitable during liver surgery, and it is an important factor affecting the prognosis of patients. IL-6 rs1800796 single nucleotide polymorphisms (SNPs) can promote synthesis and secretion of IL-6 and protect hepatocytes from IRI. In this study, we investigated the mechanisms by which IL-6 alleviates hepatic IRI. We transfected lentivirus which carries IL-6 rs1800796 to L02 cells and constructed the cell line (L02-IL6) with a high expression of IL-6. The biological function of IL-6 SNPs was explored through a cell model of hypoxia-reoxygenation (H/R). Cell viability was evaluated by CCK8 and Real-Time Cell Analysis (RTCA), and found that the viability of the L02-IL6 cells was higher than that of the control group (P < 0.01). Flow cytometry assay showed that the rate of apoptosis was significantly decreased in L02-IL6 cells. Furthermore, in comparison with the control group, the level of cleaved-caspase3, which is an important marker of apoptosis, was dramatically decreased. These differences showed that the sequence variants at rs1800796 of the IL-6 gene could improve the resistance against H/R. Moreover, the levels of autophagy-related proteins, such as LC3 and Beclin-1, were upregulated in L02-IL6 group on H/R injury, which means IL-6 could alleviate apoptosis via activating the autophagy pathway. And we also found that the STAT3 signal pathway was activated. Next, we investigated whether the exogenous treatment with IL-6 affect hepatocytes and thus play a protective role. We pre-treated the L02 cells with recombinant human IL-6 for 12 h and then made H/R treatment. We found the treatment with 100 ng/ml IL-6 alleviated the damage of L02 cells and inhibited the apoptosis. And the further study revealed the pre-treatment with IL-6 activated the STAT3 signaling pathway in the L02 cells and then caused the activation of autophagy and apoptosis inhibition. IL-6 might play a critical role in alleviating hepatic IRI, through its modulation of the STAT3 signaling pathway, and activation of autophagy. Recombinant human IL-6 might be a potential therapeutic target in hepatic IRI.

Translational medical research and liver transplantation: systematic review

Translational medicine has become a priority, but there is still a big difference between the arrival of new treatments and investment. Basic science should not be neglected because the translation from basic research is not sustained in the absence of basic research. The purpose of this literature review was to analyze the translational medicine in the liver transplant field: liver ischemia-reperfusion injury (IRI), immunosuppression, clinical and surgical complications, small-for-size syndrome (SFSS), rejection, and ongoing innovations (liver machine, liver preservation, artificial livers, and regenerative medicine). We performed a systematic literature review that were updated in October 2016. The searches were performed in the Cochrane Central Register of Controlled Trials and Review, PubMed/Medline, Embase, and LILACS databases. All the selected studies on the management of translational medical research in liver transplantation (LT) were analyzed. Initially the search found 773 articles. Methodological viewing and analysis of the articles, followed by the application of scientific models, including translational medicine in the liver transplant field. In conclusions, this review demonstrates the application of scientific research with translation medical benefits regarding the LT. The literature has a great tendency, improvements and investments in the study of translational medicine in LT. Innovative studies and technologies from basic science help to clarify clinical doubts. Moreover, evidence increases the importance of scientific research in quality of clinical practice care.

Attempted validation of 44 reported SNPs associated with tacrolimus troughs in a cohort of kidney allograft recipients

AIM

Multiple genetic variants have been associated with variation in tacrolimus (TAC) trough concentrations. Unfortunately, additional studies do not confirm these associations, leading one to question if a reported association is accurate and reliable. We attempted to validate 44 published variants associated with TAC trough concentrations.

MATERIALS & METHODS

Genotypes of the variants in our cohort of 1923 kidney allograft recipients were associated with TAC trough concentrations.

RESULTS

Only variants in CYP3A4 and CYP3A5 were significantly associated with variation in TAC trough concentrations in our validation.

CONCLUSION

There is no evidence that common variants outside the CYP3A4 and CYP3A5 loci are associated with variation in TAC trough concentrations. In the future rare variants may be important and identified using DNA sequencing.

Gene Variations of Sixth Complement Component Affecting Tacrolimus Metabolism in Patients with Liver Transplantation for Hepatocellular Carcinoma

BACKGROUND

Orthotopic liver transplantation (OLT) improves the prognosis of patients with hepatocellular carcinoma (HCC). Moreover, the complement system is a powerful immune effector that can affect liver function and process of liver cirrhosis. However, studies correlating the complement system with tacrolimus metabolism after OLT are scarce. In this study, the role of single nucleotide polymorphisms (SNPs) associated with the sixth complement component (C6) in tacrolimus metabolism was investigated during the early stages of liver transplantation.

METHODS

The study enrolled 135 adult patients treated with OLT for HCC between August 2011 and October 2013. Ten SNPs in C6 gene and rs776746 in cytochrome P450 3A5 (CYP3A5) gene were investigated. The tacrolimus levels were monitored daily during 4 weeks after transplantation.

RESULTS

Both donor and recipient CYP3A5 rs776746 allele A were correlated with decreased concentration/dose (C/D) ratios. Recipient C6 rs9200 allele G and donor C6 rs10052999 homozygotes were correlated with lower C/D ratios. Recipient CYP3A5 rs776746 allele A (yielded median tacrolimus C/D ratios of 225.90 at week 1 and 123.61 at week 2), C6 rs9200 allele G (exhibited median tacrolimus C/D ratios of 211.31 at week 1, 110.23 at week 2, and 99.88 at week 3), and donor CYP3A5 rs776746 allele A (exhibited median C/D ratios of 210.82 at week 1, 111.06 at week 2, 77.49 at week 3, and 85.60 at week 4) and C6 rs10052999 homozygote (exhibited median C/D ratios of 167.59 at week 2, 157.99 at week 3, and 155.36 at week 4) were associated with rapid tacrolimus metabolism. With increasing number of these alleles, patients were found to have lower tacrolimus C/D ratios at various time points during the 4 weeks after transplantation. In multiple linear regression analysis, recipient C6 rs9200 group (AA vs. GG/GA) was found to be related to tacrolimus metabolism at weeks 1, 2, and 3 (P = 0.005, P = 0.045, and P = 0.033, respectively), whereas donor C6 rs10052999 group (CC/TT vs. TC) was demonstrated to be correlated with tacrolimus metabolism only at week 4 (P = 0.001).

CONCLUSIONS

Recipient C6 gene rs9200 polymorphism and donor C6 gene rs10052999 polymorphism are new genetic loci that affect tacrolimus metabolism in patients with HCC after OLT.

Risk factors for and management of ischemic-type biliary lesions following orthotopic liver transplantation: A single center experience

INTRODUCTION

Biliary complications can cause morbidity, graft loss, and mortality after liver transplantation. The most troublesome biliary complications are ischemic-type biliary lesions (ITBL), which occur since transplants can now be performed after the donor has undergone circulatory death. The exact origin of this type of biliary complication remains unknown.

MATERIAL AND METHODS

A total of 528 patients were retrospectively analyzed following liver transplantation after excluding 30 patients with primary sclerosing cholangitis and those lost to follow-up from January 2007 to January 2014. The incidence of and risk factors for ITBL were evaluated.

RESULTS

Cold ischemia time (CIT) (P = 0.042) and warm ischemia time (WIT) (P = 0.006) were found to be independent risk factors for the development of ITBL. Use of the cytochrome P450 (CYP) 3A5 genotype assay to guide individualization of immunosuppressive medications resulted in significantly fewer ITBL (P = 0.027. Autoimmune hepatitis might be a risk factor for ITBL, as determined using univariate analysis (P = 0.047).

CONCLUSIONS

Efforts should be taken to minimize risk factors associated with ITBL, such as CIT and WIT. The CYP3A5 genotype assay should be used to guide selection of immunosuppressive therapy in an effort to reduce the occurrence of ITBL.

Interleukin-6 and rs1800796 locus single nucleotide polymorphisms in response to hypoxia/reoxygenation in hepatocytes

Ischemia-reperfusion injury due to hypoxia/reoxygenation (H/R) is one of the main causes of liver damage during liver surgery. Donor interleukin-6 (IL-6) rs1800796 single nucleotide polymorphisms (SNPs) affect the metabolism of tacrolimus following liver transplantation-related hepatic H/R. This study investigated the response of IL-6 and its promoter polymorphisms to hepatic H/R in liver parenchymal cells. The association between IL-6 rs1800796 SNPs and IL‑6 expression was measured in 84 disease-free liver tissues using tissue microarrays and immunohistochemistry. Subsequently, LO2G, LO2C and NC-LO2 cells were successfully constructed via stable lentivirus-mediated transfection. The effects of IL-6 and its SNPs on the biological function of LO2 cells were examined using a cell model of H/R. Our results revealed that IL-6 was mainly expressed in hepatocytes. The intermediate IL-6 expression rate in genotype CC carriers was higher than that in genotype CG/GG carriers (P=0.006), which was subsequently verified at the IL-6 mRNA level (P=0.002). The concentrations of alanine aminotransferase in the LO2G cells were significantly higher than those in the LO2C cells following H/R for 6 h and H/R for 24 h (P<0.05). The viability of the LO2C cells was higher than that of the LO2G cells (P<0.05). Furthermore, the expression of IL-6 and its downstream molecules was significantly increased in the LO2C cells compared with the LO2G cells (P<0.05). Therefore, the sequence variants of rs1800796 SNPs (G→C) exhibit an increased IL-6 transcription efficiency in liver parenchymal cells. In addition, the increased expression of IL-6 protects the hepatocytes following hepatic H/R injury.

Tacrolimus in preventing transplant rejection in Chinese patients--optimizing use

Tacrolimus is a product of fermentation of Streptomyces, and belongs to the family of calcineurin inhibitors. It is a widely used immunosuppressive drug for preventing solid-organ transplant rejection. Compared to cyclosporine, tacrolimus has greater immunosuppressive potency and a lower incidence of side effects. It has been accepted as first-line treatment after liver and kidney transplantation. Tacrolimus has specific features in Chinese transplant patients; its in vivo pharmacokinetics, treatment regimen, dose and administration, and adverse-effect profile are influenced by multiple factors, such as genetics and the spectrum of primary diseases in the Chinese population. We reviewed the clinical experience of tacrolimus use in Chinese liver- and kidney-transplant patients, including the pharmacology of tacrolimus, the immunosuppressive effects of tacrolimus versus cyclosporine, effects of different factors on tacrolimus metabolism on Chinese patients, personalized medicine, clinical safety profile, and patient satisfaction and adherence. This article provides guidance for the rational and efficient use of tacrolimus in Chinese organ-transplant patients.

Associations between polymorphisms of interleukin-6 and related cytokine genes and serum liver damage markers: a cross-sectional study in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study

Cytokines, including interleukin-6 (IL-6), play an important role in the liver. The aim of this study was to investigate associations between common polymorphisms in potential functional promoters of cytokine genes and liver damage markers among enrollees of a large Japanese cohort study. Subjects included 3257 Japanese individuals (1608 men and 1649 women, aged 35-69 years). Six single nucleotide polymorphisms (SNPs) in the promoter regions of five cytokine genes, IL1B (T-31C), IL6 (C-634G), IL8 (T-251A), IL10 (T-819C), tumor necrosis factor-A (TNFA) (T-1031C), and TNFA (C-857T), were genotyped by polymerase chain reaction. Information regarding alcohol intake, smoking habits, height, and weight was collected by a self-administered questionnaire. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured during a routine health check-up. Of the six SNPs genotyped, an IL6 polymorphism (rs1800796, C-634G) was most strongly associated with a liver damage marker, AST. Mean serum AST was significantly different among the three genotypes (mean ± SD, 22.7 ± 7.3 IU/L for CC, 22.8 ± 7.7 IU/L for CG, and 24.3 ± 8.6 IU/L for GG, p=0.011 by analysis of variance). The differences remained significant after adjustment for potential confounders by general linear models. The variations in mean serum AST and ALT levels were marked especially among men. Thus, the functional polymorphism IL6 C-634G may affect serum AST and ALT levels, possibly through different IL-6 production.

Association between interleukin-18 promoter variants and tacrolimus pharmacokinetics in Chinese renal transplant patients

PURPOSE

Interleukin 18 (IL-18) is a potent proinflammatory cytokine thought to down-regulate cytochrome P450 (CYP) enzyme activities. This study aimed to assess the potential influence of two functional single nucleotide polymorphisms (SNPs) in the IL-18 promoter region on the tacrolimus pharmacokinetics in Chinese renal transplant patients.

METHODS

We enrolled 96 renal allograft recipients receiving tacrolimus-based immunosuppressive regiments. Two functional SNPs in the IL-18 gene promoter region at the positions -137G/C (rs187283) and -607A/C (rs1946518) and one SNP (rs776746) of CYP3A5 were genotyped using a Mass ARRAY platform. Tacrolimus daily doses (mg/day) and trough tacrolimus concentration (ng/ml) were continuously recorded for 1 month after transplantation.

RESULTS

The tacrolimus C/D ratio was significantly associated with the IL-18 rs1946518 gene polymorphism in the first month after transplantation (P = 0.0225). We studied the influence of its polymorphism on tacrolimus C/D ratios in subjects with different CYP3A5 genotype backgrounds, and among patients with CYP3A5 expressers, the difference among the three genotypes was even more striking (P < 0.001). We did not find significant differences in tacrolimus C/D ratios between the IL-18 rs187238 genotypes, either nominally or according to the CYP3A5 genotype. In a simple linear regression model, age, hemoglobin (Hb), CYP3A5 gene polymorphisms, and IL-18 A-607C gene polymorphisms were associated with log-transformed tacrolimus C/D ratios (P < 0.05). In the final multiple linear regression model, CYP3A5 polymorphisms were the most important variant, accounting for 19.5 % of total variation involved in tacrolimus pharmacokinetics.

CONCLUSION

Our findings suggest that a combined analysis of CYP3A5 and IL-18 promoter polymorphisms may help clinicians develop individualized tacrolimus treatment, which is based on determining CYP3A5 genotype.

Personalized tacrolimus dose requirement by CYP3A5 but not ABCB1 or ACE genotyping in both recipient and donor after pediatric liver transplantation

Tacrolimus (TAC) is the backbone of an immunosuppressive drug used in most solid organ transplant recipients. A single nucleotide polymorphism (SNP) at position 6986G>A in CYP3A5 has been notably involved in the pharmacokinetic variability of TAC. It is hypothesized that CYP3A5 genotyping in patients may provide a guideline for TAC therapeutic regimen. To further evaluate the impact of CYP3A5 variants in donors and recipients, ABCB1 and ACE SNPs in recipients on TAC disposition, clinical and laboratory data were retrospectively reviewed from 90 pediatric patients with liver transplantation and their corresponding donors after 1 year of transplantation. The recipients with CYP3A5 *1/*1 or *1/*3 required more time to achieve TAC therapeutic range during the induction phase, and needed more upward dose during the late induction and the maintained phases, with lower C/D ratio, compared with those with CYP3A5 *3/*3. And donor CYP3A5 genotypes were found to impact on TAC trough concentrations after liver transplantation. No association between ABCB1 or ACE genotypes and TAC disposition post-transplantation was found. These results strongly suggest that CYP3A5 genotyping both in recipient and donor, not ABCB1 or ACE is necessary for establishing a personalized TAC dosage regimen in pediatric liver transplant patients.