Developments in pharmacogenetics, pharmacogenomics, and personalized medicine.

The development of Pharmacogenetics and Pharmacogenomics in Western Europe is highly relevant in the worldwide scenario. Despite the usually low institutional support, many research groups, composed of basic and clinical researchers, have been actively working for decades in this field. Their contributions made an international impact and paved the way for further studies and pharmacogenomics implementation in clinical practice. In this manuscript, that makes part of the Special Issue entitled Spanish Pharmacology, we present an analysis of the state of the art of Pharmacogenetics and Pharmacogenomics research in Europe, we compare it with the developments in Spain, and we summarize the most salient contributions since 1988 to the present, as well as recent developments in the clinical application of pharmacogenomics knowledge. Finally, we present some considerations on how we could improve translation to clinical practice in this specific scenario.

Safe Procedure for Efficient Hydrodynamic Gene Transfer to Isolated Porcine Liver in Transplantation.

Although calcineurin inhibitors are very effective as immunosuppressants in organ transplantation, complete graft acceptance remains as a challenge. Transfer of genes with immunosuppressant functions could contribute to improving the clinical evolution of transplantation. In this sense, hydrodynamic injection has proven very efficacious for liver gene transfer. In the present work, the hIL-10 gene was hydrofected 'ex vivo' to pig livers during the bench surgery stage, to circumvent the cardiovascular limitations of the procedure, in a model of porcine orthotopic transplantation with a 10-day follow-up. We used IL-10 because human and porcine proteins can be differentially quantified and for its immunomodulatory pleiotropic functions. Safety (biochemical parameters and histology), expression efficacy (RNA transcription and blood protein expression), and acute inflammatory response (cytokines panel) of the procedure were evaluated. The procedure proved safe as no change in biochemical parameters was observed in treated animals, and human IL-10 was efficaciously expressed, with stationary plasma protein levels over 20 pg/mL during the follow-up. Most studied cytokines showed increments (interferon-α, IFN-α; interleukin-1ß, IL-1ß; tumor necrosis factor α, TNFα; interleukin-6, IL-6; interleukin-8, IL-8; interleukin-4, IL-4; and transforming growth factor-ß, TGF-ß) in treated animals, without deleterious effects on tissue. Collectively, the results support the potential clinical interest in this gene therapy model that would require further longer-term dose-response studies to be confirmed.

Study of Oligonucleotides Access and Distribution in Human Peripheral Blood Mononuclear Cells.

Therapeutic oligonucleotides have achieved great clinical interest since their approval as drug agents by regulatory agencies but their access and distribution in blood cells are not completely known. We evaluated by flow cytometry the ability of short fluorescent scramble oligonucleotides (ON*) to access human peripheral blood mononuclear cells (PBMC) after incubating with ON* during 1 h and 7 days of culture follow-up 'in vitro'. Blood samples were treated with chemically modified oligonucleotides (phosphorothioate backbone and 2' O-Me ends) to resist nuclease digestion under culture conditions. The ON* internalization was determined after discarding the membrane-associated fluorescence by trypan blue quenching. Whereas the oligonucleotide accessed neutrophils and monocytes rapidly, achieving their maximum in 1 h and 24 h, respectively, lymphocytes required 7 days to achieve the maximum (80% of cells) transfection. The ON*ability to access lymphocyte types (T, B, and NK) and T cell subtypes (CD4+, CD8+, and CD4-CD8-) were similar, with T cells being more accessible. Regulatory CD4+ and CD8+ T cells were classified in low and high Foxp3 expressers, whose expression proved not to alter the ON* internalization during the first hour, achieving 53% of CD4+Foxp3+ and 40% of CD8+Foxp3+ cells. Our results contribute to understanding and improving the management of therapeutic ONs.

Influence of polymorphisms in anthracyclines metabolism genes in the standard induction chemotherapy of acute myeloid leukemia.

OBJECTIVES: Genetic variability in anthracycline metabolism could modify the response and safety of acute myeloid leukemia (AML) induction. METHODS: Polymorphisms in genes that encodes enzymes of anthracyclines metabolic pathway (CBR3: rs1056892, rs8133052, NQO1: rs1800566, NQO2: rs1143684, NOS3: rs1799983, rs2070744) were evaluated in 225 adult de novo AML patients. RESULTS: The variant CBR3 rs8133052 was associated with lower hepatotoxicity (P = 0.028). Wild-type genotype of NQO2 rs1143684 was related to higher complete remission (P = 0.014), and the variant allele with greater gastrointestinal toxicity (P = 0.024). However, the variant genotype of NQO1 rs1800566 was associated with mucositis (P = 0.018), but heterozygous genotype showed less gastrointestinal toxicity (P = 0.028) and thrombocytopenia (P = 0.009). Protective effects against nephrotoxicity and thrombocytopenia were reported with variant NOS3 rs1799983 (P = 0.006, P = 0.014), whereas carriers of NOS3 rs2070744 showed higher hepatotoxicity and thrombocytopenia (P = 0.017, P = 0.013). CONCLUSIONS: This study supports the influence of genetic variability of idarubicin metabolizing could be critical in predicting anthracycline-induced toxicities.

Mitochondrial DNA Replacement Techniques to Prevent Human Mitochondrial Diseases.

Background: Mitochondrial DNA (mtDNA) diseases are a group of maternally inherited genetic disorders caused by a lack of energy production. Currently, mtDNA diseases have a poor prognosis and no known cure. The chance to have unaffected offspring with a genetic link is important for the affected families, and mitochondrial replacement techniques (MRTs) allow them to do so. MRTs consist of transferring the nuclear DNA from an oocyte with pathogenic mtDNA to an enucleated donor oocyte without pathogenic mtDNA. This paper aims to determine the efficacy, associated risks, and main ethical and legal issues related to MRTs. Methods: A bibliographic review was performed on the MEDLINE and Web of Science databases, along with searches for related clinical trials and news. Results: A total of 48 publications were included for review. Five MRT procedures were identified and their efficacy was compared. Three main risks associated with MRTs were discussed, and the ethical views and legal position of MRTs were reviewed. Conclusions: MRTs are an effective approach to minimizing the risk of transmitting mtDNA diseases, but they do not remove it entirely. Global legal regulation of MRTs is required.

Pharmacogenetics in Neuroblastoma: What Can Already Be Clinically Implemented and What Is Coming Next?

Pharmacogenetics is one of the cornerstones of Personalized Precision Medicine that needs to be implemented in the routine of our patients' clinical management in order to tailor their therapies as much as possible, with the aim of maximizing efficacy and minimizing toxicity. This is of great importance, especially in pediatric cancer and even more in complex malignancies such as neuroblastoma, where the rates of therapeutic success are still below those of many other types of tumors. The studies are mainly focused on germline genetic variants and in the present review, state of the art is presented: which are the variants that have a level of evidence high enough to be implemented in the clinic, and how to distinguish them from the ones that still need validation to confirm their utility. Further aspects as relevant characteristics regarding ontogeny and future directions in the research will also be discussed.

MTHFR and VDR Polymorphisms Improve the Prognostic Value of MYCN Status on Overall Survival in Neuroblastoma Patients.

Single nucleotide polymorphisms (SNPs) in Pharmacogenetics can play an important role in the outcomes of the chemotherapy treatment in Neuroblastoma, helping doctors maximize efficacy and minimize toxicity. Employing AgenaBioscience MassArray, 96 SNPs were genotyped in 95 patients looking for associations of SNP with response to induction therapy (RIT) and grade 3-4 toxicities, in High Risk patients. Associations of SNPs with overall (OS) and event-free (EFS) survival in the whole cohort were also explored. Cox and logistic regression models with Elastic net penalty were employed. Association with grade 3-4 gastrointestinal and infectious toxicities was found for 8 different SNPs. Better RIT was correlated with rs726501 AG, rs3740066 GG, rs2010963 GG and rs1143684 TT (OR = 2.87, 1.79, 1.23, 1.14, respectively). EFS was affected by rs2032582, rs4880, rs3814058, rs45511401, rs1544410 and rs6539870. OS was influenced by rs 1801133, rs7186128 and rs1544410. Remarkably, rs1801133 in MTHFR (p = 0.02) and rs1544410 in VDR (p = 0.006) also added an important predictive value for OS to the MYCN status, with a more accurate substratification of the patients. Although validation studies in independent cohorts will be required, the data obtained supports the utility of Pharmacogenetics for predicting Neuroblastoma treatment outcomes.

Impact of novel polymorphisms related to cytotoxicity of cytarabine in the induction treatment of acute myeloid leukemia.

Several novel single nucleotide polymorphisms (SNPs) involved in cytarabine cytotoxicity and related to clinical outcomes have been reported recently in a series of 232 pediatric patients with acute myeloid leukemia (AML). We report the first adult AML cohort in which the influence of these SNPs in cytarabine efficacy and toxicity was analyzed. Six of polymorphisms with clinical significance in the previous study [rs12036333, rs10758713, rs9883101, rs6550826, IRX2: rs2897047, mutated in colorectal cancers (MCC): rs7729269] were analyzed in a cohort of 225 adult patients at initial diagnosis of AML treated with an induction scheme of idarubicin plus cytarabine. The variant alleles of rs12036333 and rs10758713 confirmed the previous associations with lower survival rates. The minor alleles of rs9883101 and rs6550826 were also related to lower survival, in concordance with higher cytarabine-induced cytotoxicity observed in pediatric patients. However, discordant findings between AML adult and pediatric population were observed with IRX2 rs2897047, showing higher survival in heterozygous genotype carriers. The heterozygous genotype of MCC rs7729269 was associated with higher cytarabine-induced toxicities (renal, hepatic, lung, skin toxicities), whereas lower time to thrombocytopenia recovery was associated with the MCC rs7729269 minor allele. This study confirms the influence in survival rates of these polymorphisms in an adult AML population. Novel associations between MCC SNPs and cytarabine toxicities were reported and should be validated in prospective studies involving larger groups of patients.

Human AAT gene transfer to pig liver improved by using a perfusion isolated organ endovascular procedure.

OBJECTIVE: The efficiency of endovascular liver gene transfer in pigs is evaluated by comparing two models of retrograde catheterization: single lobe catheterization with portal inflow (open procedure) versus whole liver isolation with portal and inferior vena cava blockage (close procedure). METHODS: Percutaneous endovascular catheterization was performed in pigs. Open procedure (n = 3): 8Fr balloon catheter placement in a suprahepatic branch through the jugular vein. Closed procedure (n = 3): simultaneous catheterization of the intrahepatic portal vein (transhepatic catheterization, 10Fr balloon catheter), the supra- and infrahepatic cava veins (8Fr balloon catheters through the jugular and femoral veins). In both models, 200 ml of hAAT DNA solution (20 µg/ml) were retrogradely injected at 20 ml/s. Tissue samples (8 per liver) were obtained 14 days later and the exogenous DNA, RNA and protein per cell were quantified. Blood samples were collected periodically for transaminase determination in all the animals. RESULTS: The open procedure achieved lower (approx. 1000-fold) DNA delivery, resulting in a significantly lower (p < 0.001) gene transcription (> 100-fold). The closed model also achieved a higher translation index, although differences were smaller (p < 0.001). CONCLUSIONS: Portal inflow blockage increased the delivery, transcription and translation indexes, significantly improving the final procedure efficacy when compared with an open procedure. KEY POINTS: Endovascular hydrodynamic pig liver gene transfer: open procedure versus closed procedure. Open procedure resulted in much lower DNA delivery than closed model. Open procedure reached significantly lower gene transcription index. Translation index with closed model was higher than with the open.

Low RNA translation activit limits the efficacy of hydrodynamic gene transfer to pig liver in vivo.

BACKGROUND: Hydrodynamic gene delivery has proved an efficient strategy for nonviral gene therapy in the murine liver but it has been less efficient in pigs. The reason for such inefficiency remains unclear. The present study used a surgical strategy to seal the whole pig liver in vivo. METHODS: A solution of enhanced green fluorescent protein (eGFP) DNA was injected under two different venous injection conditions (anterograde and retrograde), employing flow rates of 10 and 20 ml/s in each case, with the aim of identifying the best gene transfer conditions. The gene delivery and information decoding steps were evaluated by measuring the eGFP DNA, mRNA and protein copy number 24 h after transfection. In addition, gold nanoparticles (diameters of 4 and 15 nm) were retrogradely injected (10 ml/s) to observe, by electron microscopy, the ability of the particle to access the hepatocyte. RESULTS: The gene delivery level was higher with anterograde injection, whereas the efficacy of gene expression was better with retrograde injection, suggesting differences in the decoding processes. Thus, retrograde injection mediates gene transcription (mRNA copy/cell) equivalent to that of intermediate expression proteins but the mRNA translation was lower than that of rare proteins. Electron microscopy showed that nanoparticles within the hepatocyte were almost exclusively 4 nm in diameter. CONCLUSIONS: The results suggest that the low activity of mRNA translation limits the final efficacy of the gene transfer procedure. On the other hand, the gold nanoparticles study suggests that elongated DNA conformation could offer advantages in that the access of 15-nm particles is very limited.

Genotype and allele frequencies of drug-metabolizing enzymes and drug transporter genes affecting immunosuppressants in the Spanish white population.

Interpatient variability in drug response can be widely explained by genetically determined differences in metabolizing enzymes, drug transporters, and drug targets, leading to different pharmacokinetic and/or pharmacodynamic behaviors of drugs. Genetic variations affect or do not affect drug responses depending on their influence on protein activity and the relevance of such proteins in the pathway of the drug. Also, the frequency of such genetic variations differs among populations, so the clinical relevance of a specific variation is not the same in all of them. In this study, a panel of 33 single nucleotide polymorphisms in 14 different genes (ABCB1, ABCC2, ABCG2, CYP2B6, CYP2C19, CYP2C9, CYP3A4, CYP3A5, MTHFR, NOD2/CARD15, SLCO1A2, SLCO1B1, TPMT, and UGT1A9), encoding for the most relevant metabolizing enzymes and drug transporters relating to immunosuppressant agents, was analyzed to determine the genotype profile and allele frequencies in comparison with HapMap data. A total of 570 Spanish white recipients and donors of solid organ transplants were included. In 24 single nucleotide polymorphisms, statistically significant differences in allele frequency were observed. The largest differences (>100%) occurred in ABCB1 rs2229109, ABCG2 rs2231137, CYP3A5 rs776746, NOD2/CARD15 rs2066844, TPMT rs1800462, and UGT1A9 rs72551330. In conclusion, differences were recorded between the Spanish and other white populations in terms of allele frequency and genotypic distribution. Such differences may have implications in relation to dose requirements and drug-induced toxicity. These data are important for further research to help explain interindividual pharmacokinetic and pharmacodynamic variability in response to drug therapy.

Meta-analysis and systematic review of the effect of the donor and recipient CYP3A5 6986A>G genotype on tacrolimus dose requirements in liver transplantation.

OBJECTIVE: A meta-analysis was carried out of published studies on the effect of the CYP3A5 6986A>G polymorphism in liver donors and transplant recipients on tacrolimus pharmacokinetics. METHODS: Cohort studies that evaluated the relationship between the CYP3A5 polymorphism in liver donors and transplant recipients and tacrolimus, trough blood concentration normalized for the daily dose (C) per kilogram body weight (D) (C/D, ng/ml/mg/kg/day) up to 1 year after transplantation, were included. Data were not restricted by patient age or the language or journal of publication. A literature search was conducted using the Cochrane Library, MEDLINE, EMBASE, and grey literature, and articles published up to 24 April 2013 were selected. Data were pooled (random-effects model), and the results were expressed as the mean difference of the corresponding C/D ratios and 95% confidence intervals. RESULTS: Six studies involving donor genotypes (254 patients) and four involving recipient genotypes (180 patients) were ultimately included. The meta-analysis showed the C/D ratio to be significantly higher in recipients with nonexpresser donor variants at all time points. In recipients, the variant did not influence the C/D ratio. CONCLUSION: The presence of the CYP3A5 6986A>G polymorphism in the donor affects tacrolimus pharmacokinetics in the recipient, although only the evidence available for the first month after transplantation was of adequate quality for demonstrating a significant difference. The evidence provided here shows no effect of the recipient genotype; however, the quality of the evidence was low, thereby precluding the drawing of firm conclusions.

Increased hospital stay and allograft dysfunction in renal transplant recipients with Cyp2c19 AA variant in SNP rs4244285.

Pharmacogenetics correlates certain genetic variants, such as single nucleotide polymorphisms (SNPs), with blood drug levels, efficacy, and adverse effects of the treatment. Tacrolimus is mainly metabolized via CYP3A4/5, whereas CYP2C19 and CYP3A4/5 are responsible for omeprazole metabolism. Omeprazole inhibits tacrolimus metabolism via CYP3A5 in patients carrying variant alleles of CYP2C19, increasing tacrolimus blood concentrations. Seventy-five renal transplant recipients treated with tacrolimus and concomitant omeprazole were genotyped in a panel of 37 SNPs with use of Sequenom MassArray. The patients with CYP2C19*2/*2 genotype (n = 4) showed a median posttransplantation hospital stay of 27.5 days (95% confidence interval [CI], 23-39 days), compared with 12 days (95% CI, 10-15 days) in patients with CYP2C19*1/*1 or CYP2C19*1/*2 (n = 71; P = 0.016, Kruskal-Wallis test).The difference in hospital stay was directly correlated with an increase in tacrolimus levels (C(min)/[dose/weight]) during the first week after trasplantation (in 59 patients with data on levels; P = 0.021, Kruskal-Wallis), excluding the patients with atypical metabolisms due to CYP3A5*1/*3 or CYP3A5*1/*1 genotype. Recipients with CYP2C19*2/*2 genotype also showed allograft delayed function (acute tubular necrosis in 3 patients). Genotyping of CYP3A5 and CYP2C19 in renal transplantation should be considered to be of interest when treating with tacrolimus and omeprazole, because CYP2C19*2/*2 variant indirectly elicits an increase of tacrolimus blood levels and, in our study population, the adverse effects described.

Personalized Medicine in Infant Population with Cancer: Pharmacogenetic Pilot Study of Polymorphisms Related to Toxicity and Response to Chemotherapy.

BACKGROUND: Pharmacogenetics is a personalized medicine tool that aims to optimize treatments by adapting them to each individual's genetics, maximizing their efficacy while minimizing their toxicity. Infants with cancer are especially vulnerable, and their co-morbidities have vital repercussions. The study of their pharmacogenetics is new in this clinical field. METHODS: A unicentric, ambispective study of a cohort of infants receiving chemotherapy (from January 2007 to August 2019). The genotypes of 64 patients under 18 months of age were correlated with severe drug toxicities and survival. A pharmacogenetics panel was configured based on PharmGKB, drug labels, and international experts' consortiums. RESULTS: Associations between SNPs and hematological toxicity were found. Most meaningful were: MTHFR rs1801131 GT increasing the anemia risk (OR 1.73); rs1517114 GC, XPC rs2228001 GT, increasing neutropenia risk (OR 1.50 and 4.63); ABCB1 rs1045642 AG, TNFRSF11B rs2073618 GG, CYP2B6 rs4802101 TC and SOD2 rs4880 GG increasing thrombocytopenia risk (OR 1.70, 1.77, 1.70, 1.73, respectively). Regarding survival, MTHFR rs1801133 GG, TNFRSF11B rs2073618 GG, XPC rs2228001 GT, CYP3A4 rs2740574 CT, CDA rs3215400 del.del, and SLC01B1 rs4149015 GA were associated with lower overall survival probabilities (HR 3.12, 1.84, 1.68, 2.92, 1.90, and 3.96, respectively). Lastly, for event-free survival, SLC19A1 rs1051266 TT and CDA rs3215400 del.del increased the relapse probability (HR 1.61 and 2.19, respectively). CONCLUSIONS: This pharmacogenetic study is a pioneer in dealing with infants under 18 months of age. Further studies are needed to confirm the utility of the findings in this work to be used as predictive genetic biomarkers of toxicity and therapeutic efficacy in the infant population. If confirmed, their use in therapeutic decisions could improve the quality of life and prognosis of these patients.

Pharmacogene Variants Associated with Liver Transplant in a Twelve-Year Clinical Follow-Up.

Some gene polymorphisms have been previously associated individually with tacrolimus efficacy and toxicity, but no long-term study to determine the role of pharmacogene variants in the clinical evolution of liver-transplanted patients has been addressed so far. In the present work, we analyzed the relation between highly-evidenced genetic polymorphisms located in relevant pharmacogenes and the risk of suffering premature death and other comorbidities such as cancer, diabetes mellitus, arterial hypertension, graft rejection, infections and nephrotoxicities in a cohort of 87 patients (8 were excluded due to early loss of follow-up) transplanted at Hospital La Fe in Valencia (Spain) during a 12-year follow-up. Employing a logistic regression model with false discovery rate penalization and Kaplan-Meier analyses, we observed significant association between survival rates and metabolizer genes. In this sense, our results show an association between MTHFR gene variants in donor rs1801133 (HR: 7.90; p-value: 0.032) and recipient rs1801131 (HR: 7.34; p-value: 0.036) and the group of patients who died during the follow-up period, supporting the interest of confirming these results with larger patient cohorts. In addition, donor polymorphisms in UGT1A9 metabolizer gene rs6714486 (OR: 0.13; p-value: 0.032) were associated with a lower risk of suffering from de novo cancer. Genetic variants in CYP2B6 metabolizer gene rs2279343 demonstrated an association with a risk of infection. Other variants in different locations of SLCO1A2, ABCC2 and ABCB1 transporter genes were associated with a lower risk of suffering from type 2 diabetes mellitus, chronic and acute nephrotoxicities and arterial hypertension. Results suggest that pharmacogenetics-derived information may be an important support for personalized drug prescription, clinical follow-up and the evolution of liver-transplanted patients.

Regulatory T cells and vaccine effectiveness in older adults. Challenges and prospects.

Since the discovery of lymphocytes with immunosuppressive activity, increasing interest has arisen in their possible influence on the immune response induced by vaccines. Regulatory T cells (Tregs) are essential for maintaining peripheral tolerance, preventing autoimmune diseases, and limiting chronic inflammatory diseases. However, they also limit beneficial immune responses by suppressing anti-infectious and anti-tumor immunity. Mounting evidence suggests that Tregs are involved, at least in part, in the low effectiveness of immunization against various diseases where it has been difficult to obtain protective vaccines. Interestingly, increased activity of Tregs is associated with aging, suggesting a key role for these cells in the lower vaccine effectiveness observed in older people. In this review, we analyze the impact of Tregs on vaccination, with a focus on older adults. Finally, we address an overview of current strategies for Tregs modulation with potential application to improve the effectiveness of future vaccines targeting older populations.

Multicompartmental Lipopolyplex as Vehicle for Antigens and Genes Delivery in Vaccine Formulations.

Vector design and its characterization is an area of great interest in current vaccine research. In this article, we have formulated and characterized a multicompartmental lipopolyplex, which associates multiple liposomes and polyplexes in the same complex. These particles allow the simultaneous delivery of lipid or water-soluble antigens associated with genes to the same cell, in much higher amounts than conventional lipopolyplexes. The vector characterization and optimization were carried out using liposomes with entrapped carboxyfluorescein and adapted electrophoretic assays. Two types of lipopolyplexes (containing hydrophilic or lipophilic antigens) were employed to evaluate their interest in vaccination. The lipopolyplex loaded with an extract of water-soluble melanoma proteins proved to efficiently induce humoral response in murine melanoma model, increasing the levels of IgM and IgG. The specificity of the immune response induced by the lipopolyplex was demonstrated in mice with the lipopolyplex containing the GD3 ganglioside lipid antigen, abundant in melanoma cells. The levels of anti-GD3 IgG increased markedly without modifying the expression of humoral antibodies against other gangliosides.

Integrated CGH/WES Analyses Advance Understanding of Aggressive Neuroblastoma Evolution: A Case Study.

Neuroblastoma (NB) is the most common extra-cranial malignancy in preschool children. To portray the genetic landscape of an overly aggressive NB leading to a rapid clinical progression of the disease, tumor DNA collected pre- and post-treatment has been analyzed. Array comparative genomic hybridization (aCGH), whole-exome sequencing (WES), and pharmacogenetics approaches, respectively, have identified relevant copy number alterations (CNAs), single nucleotide variants (SNVs), and polymorphisms (SNPs) that were then combined into an integrated analysis. Spontaneously formed 3D tumoroids obtained from the recurrent mass have also been characterized. The results prove the power of combining CNAs, SNVs, and SNPs analyses to assess clonal evolution during the disease progression by evidencing multiple clones at disease onset and dynamic genomic alterations during therapy administration. The proposed molecular and cytogenetic integrated analysis empowers the disease follow-up and the prediction of tumor recurrence.

Impact of combinations of single-nucleotide polymorphisms of anthracycline transporter genes upon the efficacy and toxicity of induction chemotherapy in acute myeloid leukemia.

Anthracycline uptake could be affected by influx and efflux transporters in acute myeloid leukemia (AML). Combinations of single-nucleotide polymorphisms (SNPs) of wild-type genotype of influx transporters (SLC22A16, SLCO1B1) and homozygous variant genotypes of ABC polymorphisms (ABCB1, ABCC1, ABCC2, ABCG2) were evaluated in 225 adult de novo AML patients. No differences in complete remission were reported, but higher induction death was observed with combinations of SLCO1B1 rs4149056 and ABCB1 (triple variant haplotype, rs1128503), previously associated with ABCB1 and SLCO1B1 SNPs. Several combinations of SLCO1B1 and SLC22A16 with ABCB1 SNPs were associated with higher toxicities, including nephrotoxicity and hepatotoxicity, neutropenia, previously related to ABCB1, and a novel correlation with mucositis. Combination of SLC22A16 rs714368 and ABCG2 rs2231142 was related to cardiac toxicity, reproducing previous correlations with ABCG2. This study shows the impact of transporter polymorphisms in AML chemotherapy safety. Further prospective studies with larger populations are needed to validate these associations.

Naked DNA delivery to whole pig cardiac tissue by coronary sinus retrograde injection employing non-invasive catheterization.

BACKGROUND: Hydrodynamic injection has demonstrated to be very efficient in the liver of small animals, although this procedure must be translated to the clinical practice in a milder but no less efficient way. The present study evaluates the capacity of non-invasive interventional catheterization as a procedure for naked DNA delivery to the heart in large animals. METHODS: Two catheters were placed in the coronary sinus: one of them to block blood circulation and the other to retrogradely inject 50 ml of a saline solution of DNA (20 µg/ml) containing the enhanced green fluorescent protein (EGFP) gene, at a flow rate of 5 ml/s. RESULTS: The results obtained show that EGFP protein, identified by immunohistochemistry, was present and widely distributed throughout the atrial and ventricular cardiac tissue. This observation agrees with the efficiency of EGFP gene delivery resulting in 1-200 EGFP gene copies per endogenous haploid genome. However, the transcription efficiency of the exogenous EGFP gene was at a ratio of 0.2-10 copies with respect to the endogenous GAPDH gene, suggesting that optimized gene constructs for expression in cardiac tissue could increase the final efficacy of gene transfer. CONCLUSIONS: We conclude that the retrovenous injection of naked DNA in the coronary sinus employing the catheterization technique is an easy and probably safe method for whole cardiac gene transfer.