The Genetic Polymorphism of CYP3A4 rs2242480 is Associated with Sirolimus Trough Concentrations Among Adult Renal Transplant Recipients

Background:: The large interindividual variability in the genetic polymorphisms of sirolimus (SIR)- metabolizing enzymes, transporters, and receptors can lead to qualitatively and quantitatively distinct therapeutic responses. Objective:: We examined the impact of numerous candidate single-nucleotide polymorphisms (SNPs) involved in the trough concentration of SIR-based immunosuppressant regimen. Method:: This is a retrospective, long-term cohort study involving 69 renal allograft recipients. Total DNA was isolated from recipient blood samples and trough SIR concentrations were measured by microparticle enzyme immunoassay. Genome sequence reading was targeted based on next-generation sequencing. The association of tagger SNPs to SIR trough concentrations with non-genetic covariate adjusting was analyzed using logistic regression. Results:: A total of 300 SNPs were genotyped in the recipient DNA samples using target sequencing analysis. Only the SNP of CYP3A4 (Ch7: 99361466 C>T, rs2242480) had a significantly higher association with SIR trough concentration as compared to the other 36 tagger SNPs. The mean trough SIR concentration of patients in the CYP3A4 rs2242480-CC group was more significant compared to that of the CYP3A4 rs2242480-TC and TT group, respectively 533.3; 157.4 and 142.5 (ng/ml)/mg/kg, P<0.0001. After adjusting the SNPs, there was no significant association between clinical factors such as age, follow-up period, the incidence of delayed graft function, immunosuppression protocol, and sex with SIR trough concentration. Conclusion:: These findings indicated a significant association of polymorphism in the CYP3A4 (Ch7: 99361466 C>T, rs2242480) with SIR trough concentration after 1-year administration in patients who have undergone kidney transplantation.

EFEK FORTIFIKASI VITAMIN B12 TERHADAP KADAR VITAMIN B12 SERUM DAN HOMOSISTEIN SERUM PADA VEGETARIAN

Introduction: Vegetarians consume plant-based foods with or without eggs and milk. Vegetarians are at risk of vitamin B12 deficiency, as natural sources of vitamin B12 are limited to animal-based foods. Vitamin B12 deficiency can lead to megaloblastic anemia, nerve damage and increase homocysteine level. Higher homocysteine level can increase the risk of coronary heart disease and stroke. The objective of this study was to investigate the effect of vitamin B12 fortification on the level of serum vitamin B12 and homocysteine in vegetarian. Method: The research design was an experimental study, community trial. The samples were 42 vegetarians with vitamin B12 deficiency (< 156 pmol/L) selected from 118 vegetarians as members of Indonesia Vegetarian Society (IVS) Pekanbaru, treated by vitamin B12 fortified oatmeal for three months from March to June 2010. Serum vitamin B12 and homocysteine were measured by electrochemiluminescent immunoassay and microparticle enzyme immunoassay method respectively. Result: Prevalence of vitamin B12 deficiency in vegetarian was 35.6%. Statistical analysis showed a significant increase of serum vitamin B12 from 124.6 to 284.6 pmol/L (p=0.001) and significant decrease of serum homocysteine from 20.1 to 15.1 µmol/L (p=0.001). Conclusion: Consumption of vitamin B12 fortified oatmeal increases the level of serum vitamin B12 and decreases the level of serum homocysteine significantly in vegetarian with vitamin B12 deficiency.

Correlation between serum concentrations of homocysteine, folate and vitamin B12 in patients with schizophrenia

Introduction: The role of hyperhomocysteinemia in psychotic disorder can be explained by partial antagonism of homocysteine on NMDA-glycine receptor. Plasma concentration of homocysteine is an indicatorof the status of the B-vitamins (folate, B12, B6). Folate deficiency may have different effects on the neurochemical processes of schizophrenia. This suggests that the association between elevated levels of homocysteine and schizophrenia is biologically very likely.Methods: The study was consisted of 20 patients with schizophrenia and 20 healthy controls. We investigated the levels of serum homocysteine concentration using AxSYM (Abbott), levels of folate assay istwo-step immunoassay to determine the presence folate in human serum using CMIA (chemiluminescent microparticle immunoassay) technology and Axsym Holo Tc is microparticle enzyme immunoassay (MEIA)for the quantitative determination of human holo TC in serum and determination defi cit of vitamin B 12.Results: The patients group has higher levels of homocysteine in compare with controls group for 3.85 μmol/L while the concentration of folate in the group of patients was lower for 9.17 ng/mL. The mean level of vitamin B-12 in investigation groups were in reference range 19.1-119 pmol/L, but patient group have lower average concentration of vitamin B-12 lower for 24.81 pmol/L compared to the control group.Conclusion: Our results showed that homocysteine concentration is inversely proportionate to folate concentration,i.e. as homocysteine concentration in serum increases, folate concentration falls. Shizophrenicpatients with elevated tHcy level and low folate levels should have vitamin supplementation with folic acid.

Interactions between Tacrolimus and Metronidazole in a renal transplant patient

We present a case which reports the occurrence of a potential elevation of Tacrolimus (Tac) plasma levels to toxic values in a renal transplant recipient after adding Metronidazole (Met) to the medication regimen. A 30-year old female, status post living-related renal transplant, who was stabilized on Tac 4.5 mg, twice daily, for 4 months, presented to the clinic with diarrhea. We used Microparticle Enzyme Immunoassay (MEIA) to determine Tac trough concentration (trough concentrations 5–10 ng/ml). After 6 days of Met therapy on 1.5 g/d, Tac trough concentration and serum creatinine (sCr) increased to 20.2 ng/ml and 7.8 mg/dl respectively. Met therapy was discontinued, also one dose of Tac was withheld, while daily dose was decreased to 2 mg/d. Four days after Met discontinuation, Tac concentration dropped to 8.7 ng/ml, sCr to 2.1 mg/dl, warranting Tac dose increase to 3 mg/d. Co-administration of Tac with Met may result in elevated Tac concentrations, possibly leading to tacrolimus nephrotoxicity. Clinicians should be aware of this potential interaction and closely monitor Tac concentration and renal function.

Comparison of ARCHITECT chemiluminiscent microparticle immunoassay for determination of Troponin I in serum with AXYM MEIA technology

Introduction: The aim of this study was determination of troponin I at serum using Architect (Abbott) and AxSYM System (Abbott). Troponin is regulatory subunit of the troponin complex associate with actin filament within muscle cells and it is a marker for diagnosis of myocardial damage.Methods: We used Architect STAT chemiluminescent microparticle immunoassay (CMIA) and AxSYM microparticle Enzyme Immunoassay (MEIA), techniques for quantitative determination of cardiac TnI in human serum or plasma. At our study we have proved precision, reproducibility and accuracy from both methods. The investigation included patients (n=119) who have myocardial infarction or ischemic heart damage and were treated at cardiology, emergency, internal medicine and neurology unit in Clinical Center University in Sarajevo.Results: The precision for three controls using Architect STAT TnI asssay technology were 3.6 – 5.2 % and reproducibility was 3.7 to 5.6 %. The AxSYM STAT TnI has precision for three controls 4.3–6.6 % and reproducibilitywas from 4.8 to 7.8 %. We have got very good correlation between Architect and AxSYM technology r = 0.999 in the investigation of troponin I in serum.Conclusions: We can conclude that chemiluminescent troponin assay I (Architect) showed good analytical performance and gave new possibility at troponin I determination.

Different Influences on Tacrolimus Pharmacokinetics by Coadministrations of Zhi Ke and Zhi Shi in Rats

Tacrolimus, an immunosuppressant with narrow therapeutic window, has been used widely in transplant patients. Grapefruit juice and pomelo have been reported to increase the blood levels of tacrolimus. Zhi Ke and Zhi Shi, the ripe peels and unripe fruits ofCitrus aurantiumwhich is chemotaxonomically related to grapefruit and pomelo, are in wide use in clinical Chinese medicine. To investigate the possible interaction of these twoCitrusherbs with tacrolimus, male Sprague-Dawley rats were orally given tacrolimus (1.5 mg/kg) with and without Zhi Ke and Zhi Shi decoctions in a cross-over design. Blood samples were withdrawn via cardiopuncture at specific time and quantitated by a microparticle enzyme immunoassay. In addition, to explore the mechanism of interaction, LS 180 cell line was used for the transport study of rhodamine 123, a typical substrate of P-glycoprotein (P-gp). The results showed that Zhi Shi significantly decreased theCmax⁡andAUC0-tof tacrolimus by 72.4% and 72.0%, respectively, whereas Zhi Ke did not affect tacrolimus pharmacokinetics. LS 180 cell line study indicated that Zhi Shi increased the efflux activity of P-gp, enabling us to explain the decreased oral bioavailability of tacrolimus caused by Zhi Shi. Hence, we suggest that Zhi Shi be contraindicated for transplant patients treated with tacrolimus to reduce the risk of allograft rejection.