CYP3A5 and PPARA genetic variants are associated with low trough concentration to dose ratio of tacrolimus in kidney transplant recipients.

PURPOSE: Genetic polymorphisms have been associated with variation in the metabolism of tacrolimus (TAC) in kidney transplant patients. This study is aimed at assessing the impact of allelic variants of CYP3A5 and PPARA genes on the pharmacokinetics (PK) of TAC in Brazilian kidney transplant recipients in the first-year post-transplant. METHODS: A total of 127 patients were included for genetic evaluation. Genomic DNA was isolated from peripheral blood and real-time PCR was used to analyze the main polymorphisms described for the genes CYP3A5 (rs776746; C > G) and PPARA (rs4823613; A > G and rs4253728; G > A). RESULTS: CYP3A5 expressors showed a lower Co/dose ratio than non-expressors, with the median values of this parameter <1.01 ng/mL/mg in the first group at all evaluated times. Additionally, PPARA variant homozygotes had a lower Co/D ratio than wild allele carriers in the 12-month post-transplant period, with a median value of 0.65 ng/mL/mg. In the CYP3A5 expressers, the presence of the variant homozygous genotype PPARA was associated with a lower value of Co/D compared with the other genotypic groups at month 12. CONCLUSION: In the population under study, polymorphisms on CYP3A5 and PPARA were identified as determining and independent factors associated with the reduction of Co/D of TAC. Thus, the genotyping of these genetic variants may be a useful tool for the individualized prescription of TAC in kidney transplant patients.

Impact of POR*28 Variant on Tacrolimus Pharmacokinetics in Kidney Transplant Patients with Different CYP3A5 Genotypes.

BACKGROUND: The introduction of tacrolimus (TAC) to clinical practice was essential to the establishment of transplantation as a therapy for patients with chronic renal disease. However, the higher interindividual variation of TAC metabolism has been an important limiting factor for its clinical use. Although the relationship between CYP3A5 polymorphisms and TAC pharmacokinetics (PK) is well established, the effects of other genetic variants on TAC metabolism, such as POR*28, still remain uncertain. OBJECTIVE: The study aimed to evaluate the impact of POR variants on TAC PK in renal transplant patients with different CYP3A5 genotypes (expressers and non-expressers). METHODS: A total of 115 patients were included in this study. Genomic DNA was isolated from peripheral blood, and the real-time PCR technique was used to analyze the polymorphism POR rs1057868; C>T. RESULTS: During the initial post-transplant period, variant allele carriers (*1/*28 and *28/*28) showed a lower TAC dose requirement than POR wild homozygotes (*1/*1). Regarding the influence of the different polymorphisms of POR within the CYP3A5 expresser and non-expresser groups, no differences were observed in any of the PK parameters analyzed during 12 months after transplantation. CONCLUSION: In the studied population, the variant allelic POR*28 was significantly associated with lower TAC dose requirements and higher Co/D ratio in the first-month post-transplant. However, the effects of this polymorphism on the CYP3A5 enzyme activity were not observed.

Role of the addition of cabergoline to the management of acromegalic patients resistant to longterm treatment with octreotide LAR.

The aim of this prospective open trial was to evaluate the efficacy in normalizing IGF-I levels of the addition of cabergoline to the treatment of acromegalic patients partially responsive to Octreotide-LAR (OCT-LAR), a long acting somatotastin analog (SSA). Fifty-two patients who did not achieve hormonal control after longterm therapy (at least, 12 months) with OCT-LAR (30 mg every 28 days intramuscularly) were given cabergoline in addition to the SSA treatment. Normalization of IGF-I levels was achieved in 40.4% of patients by 6 months after the addition of cabergoline (1.0-3.0 mg/week; mean, 2.19 ± 0.64), and these patients were considered responsive. Compared to non-responsive subjects, responsive patients had significantly lower mean %ULNR-IGF-I and GH levels. However, the rate of hyperprolactinemia and positive immunohistochemical staining for PRL was similar in both groups, before the addition of cabergoline. Responsive patients were followed for at least 12 months on combination treatment and persisted with normal IGF-I levels. Patients with baseline %ULNR IGF-I up to 220% and/or GH up to 5 ng/ml were those who benefited the most from combination treatment. No patients with %ULNR-IGF-I>250% reached normalization of IGF-I levels. Our findings demonstrated that the addition of cabergoline, even at relatively low doses, is effective in both short- and long-term control of IGF-I levels in acromegalic patients partially responsive to octreotide LAR, particularly in those with mild/moderately elevated GH/IGF-levels, irrespective of prolactin status.

Genetic Screening of Patients with Thyrotoxic Hypokalemic Periodic Paralysis: An Experience from a Tertiary Care Hospital in the Northeast of Brazil.

BACKGROUND: Thyrotoxic Hypokalemic Periodic Paralysis (THPP) is a rare neuromuscular disease characterized by recurrent episodes of skeletal muscle weakness associated with hypokalemia. Alterations in protein-encoding genes that are part of ion channels seem to be related to the development of this disease. However, the pathogenic potential of some variants in these genomic regions is not yet fully understood. The aim of this study was to screen genetic alterations in regions coding for calcium (cav1.1), sodium (nav1.4), and potassium (Kir2.6) channels, evaluating its impact on the phenotype of patients with THPP. METHODS: Four patients with a diagnosis of THPP followed by the Endocrinology Service of the University Hospital of the Federal University of Maranhão (Brazil) were investigated for the presence of molecular abnormalities in CACNA1S, SCN4A, and KCNJ18 genes. RESULTS: The KCNJ18 analysis revealed at least one polymorphic variant in each patient. Considering the haplotypic classification of R39Q, R40H, A56E, and I249V variants, two cases were named Kir2.6_RRAI and the other two patients were named Kir2.6_QHEV. No patient had point mutations in the regions evaluated for CACNA1S and SCN4A genes. CONCLUSION: The identification of the Kir2.6_RRAI and Kir2.6_QHEV haplotypes reinforces the existence of two main haplotypes involving these four loci of the KCNJ18gene. On the other hand, point mutations in CACNA1S, SCN4A, and KCNJ18 genes do not seem to be the main mechanism of pathogenesis of THPP, indicating that many questions about this topic still remain unclear. So, the diagnosis of this rare disorder should still be based on clinical and biochemical aspects presented by the patient.

Sample transport validation: experience of a medium-sized laboratory / Validação do transporte de amostras: experiência de um laboratório de médio porte

ABSTRACT INTRODUCTION: The adequacy of biological samples is a critical and important item in the clinical laboratory, so that reliable results can be obtained for patients. OBJECTIVE: To ensure integrity and stability of biological samples during the transport process. METHOD: Concurrent validation was carried out - in parallel with the production process and distribution of the product, from January to March 2017. The blood samples were packaged primarily in tube racks, and those of urine, feces and microbiological materials were packed in plastic bags. Materials were wrapped in a blanket of absorbent material to ensure temperature integrity and to avoid possible material losses. Thermal bags were the containers used to carry the samples. There were five transport routes, with two daily routes for each collection unit. A recommendation of the number of ice packs, predefined by the laboratory, was followed. RESULTS AND CONCLUSION: In the first month, the pre-established temperatures (blood: 10°C to 22°C/urine-feces: 2°C to 8°C) were not reached until arrival at the central laboratory, and the amount of ice in each bag was gradually increased, daily, until reaching the ideal temperature, in all collection units and the central. Transport routes were changed three times in the most distant units. Materials that arrived outside specifications were processed with restrictions, and results were evaluated by the professional responsible for the release. After these modifications, the temperature records of the biological materials were in accordance with the current legislation and the defined specifications, thus validating the process.

RESUMO INTRODUÇÃO: A adequação das amostras biológicas é um item crítico e importante no laboratório clínico, para que possamos oferecer resultados confiáveis aos pacientes. OBJETIVO: Garantir a integridade e a estabilidade das amostras biológicas durante o processo de transporte. MÉTODO: Foi realizada validação concorrente - concomitantemente ao processo produtivo e à distribuição do produto, no período de janeiro a março de 2017. As amostras de sangue foram acondicionadas primariamente em galerias; as de urina, fezes e materiais microbiológicos, em sacos plásticos. Os materiais foram envoltos por uma manta de material absorvente para garantir a integridade da temperatura e evitar possíveis perdas de material. Maletas térmicas foram os recipientes utilizados para transportar as amostras. Havia cinco rotas de transporte, com dois percursos diários para cada unidade de coleta. Foi seguida a recomendação da quantidade de barras de gelo predefinida pelo laboratório. RESULTADOS E CONCLUSÃO: No primeiro mês, as temperaturas preestabelecidas (sangue: 10°C a 22°C/urina e fezes: 2°C a 8°C) não foram atingidas até a chegada à matriz, e aumentou-se gradativamente a quantidade de gelo em cada maleta, com avaliações diárias, até se atingir a temperatura ideal, em todas as unidades de coleta e na matriz. Foi realizada mudança nas rotas de transporte com frequência de três vezes nas unidades mais distantes. Os materiais que chegaram fora das especificações foram processados com restrição; e os resultados, avaliados pelo profissional responsável pela liberação. Após essas modificações, os registros de temperatura dos materiais biológicos estavam de acordo com a legislação vigente e as especificações definidas, validando, portanto, o processo.