Contaminants in Dietary Supplements: Toxicity, Doping Risk, and Current Regulation

Athletes, both amateur and professional, often resort to the consumption of nutritional supplements without professional supervision and without being aware of the risks they may entail. We conducted an exhaustive literature search to determine the most common substances found as contaminants in dietary supplements. For each substance, we analyzed its mechanism of action, clinical indication, health risk, and putative use as doping agent. In addition, we evaluated the current regulation of these supplements. Contamination of nutritional supplements (accidental or intentional), especially with steroids and stimulants, is a hazardous situation. The prolonged consumption of these products without being aware of their composition can cause serious health risks and, in the case of professional athletes, a possible sanction for doping.

Prognostic Significance of Amino Acid and Biogenic Amines Profiling in Chronic Kidney Disease

There is a pressing need for more precise biomarkers of chronic kidney disease (CKD). Plasma samples from 820 subjects [231 with CKD, 325 with end-stage kidney disease (ESKD) and 264 controls] were analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) to determine a metabolic profile of 28 amino acids (AAs) and biogenic amines to test their value as markers of CKD risk and progression. The kynurenine/tryptophan ratio showed the strongest correlation with estimated glomerular filtration rate values (coefficient = -0.731, p < 0.0001). Models created with orthogonal partial least squares-discriminant analysis (OPLS-DA) containing the metabolic signature showed a high goodness of fit and predictability for controls/CKD (R2X:0.73:R2Y:0.92:Q2:0.92, p < 0.0001) and lower values for CKD/ESKD (R2X:0.56:R2Y:0.59:Q2:0.55, p < 0.0001). Based on generated VIP scores, the most relevant markers for segregating samples into control/CKD and CKD/ESKD groups were citrulline (1.63) and tryptophan (1.47), respectively. ROC analysis showed that the addition of the metabolic profile to a model including CKD classic risk factors improved the AUC from 86.7% (83.6-89.9) to 100% (100-100) for CKD risk (p < 0.0001) and from 63.0% (58.2-67.8) to 96.5% (95.3-97.8) for the risk of progression from CKD to ESKD (p < 0.0001). Plasma concentrations of AAs and related amines may be useful as diagnostic biomarkers of kidney disease, both for CKD risk and for progression of CKD patients to ESKD.

Recent Advances and Remaining Challenges in the Management of Diabetic Kidney Disease

Diabetic kidney disease (DKD), which refers to pathologic structural and functional changes observed in the kidneys of patients with diabetes mellitus (DM), is the greatest contributor to CKD and the most common cause of end-stage kidney disease (ESKD) worldwide [...].

Influence of variability in the cyclooxygenase pathway on cardiovascular outcomes of nephrosclerosis patients

Nephrosclerosis patients are at an exceptionally high cardiovascular (CV) risk. We aimed to determine whether genetic variability represented by 38 tag-SNPs in genes of the cyclooxygenase pathway (PTGS1, PTGS2, PTGES, PTGES2 and PTGES3) leading to prostaglandin E2 (PGE2) synthesis, modified CV traits and events in 493 nephrosclerosis patients. Additionally, we genotyped 716 controls to identify nephrosclerosis risk associations. The addition of three variants, namely PTGS2 rs4648268, PTGES3 rs2958155 and PTGES3 rs11300958, to a predictive model for CV events containing classic risk factors in nephrosclerosis patients, significantly enhanced its statistical power (AUC value increased from 78.6 to 87.4%, p = 0.0003). Such increase remained significant after correcting for multiple testing. In addition, two tag-SNPs (rs11790782 and rs2241270) in PTGES were linked to higher systolic and diastolic pressure [carriers vs. non-carriers = 5.23 (1.87-9.93), p = 0.03 and 5.9 (1.87-9.93), p = 0.004]. PTGS1(COX1) rs10306194 was associated with higher common carotid intima media thickness (ccIMT) progression [OR 1.90 (1.07-3.36), p = 0.029], presence of carotid plaque [OR 1.79 (1.06-3.01), p = 0.026] and atherosclerosis severity (p = 0.041). These associations, however, did not survive Bonferroni correction of the data. Our findings highlight the importance of the route leading to PGE2 synthesis in the CV risk experienced by nephrosclerosis patients and add to the growing body of evidence pointing out the PGE2 synthesis/activity axis as a promising therapeutic target in this field.

Polymorphisms in glucose homeostasis genes are associated with cardiovascular and renal parameters in patients with diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) has become the major cause of end-stage kidney disease and is associated to an extremely high cardiovascular (CV) risk.

METHODS

We screened 318 DN patients for 23 SNPs in four glucose transporters (SLC2A1, SLC2A2, SLC5A1 and SLC5A2) and in KCNJ11 and ABCC8, which participate in insulin secretion. Regression models were utilised to identify associations with renal parameters, atherosclerosis measurements and CV events. In addition, 506 individuals with normal renal function were also genotyped as a control group.

RESULTS

In the patient's cohort, common carotid intima media thickness values were higher in carriers of ABCC8 rs3758953 and rs2188966 vs. non-carriers [0.78(0.25) vs. 0.72(0.22) mm, p < 0.05 and 0.79(0.26) vs. 0.72(0.22) mm, p < 0.05], respectively. Furthermore, ABCC8 rs1799859 was linked to presence of plaque in these patients [1.89(1.03-3.46), p < 0.05]. Two variants, SLC2A2 rs8192675 and SLC5A2 rs9924771, were associated with better [OR = 0.49 (0.30-0.81), p < 0.01] and worse [OR = 1.92 (1.15-3.21), p < 0.05] CV event-free survival, respectively. With regard to renal variables, rs841848 and rs710218 in SLC2A1, as well as rs3813008 in SLC5A2, significantly altered estimated glomerular filtration rate values [carriers vs. non-carriers: 30.41(22.57) vs. 28.25(20.10), p < 0.05; 28.95(21.11) vs. 29.52(21.66), p < 0.05 and 32.03(18.06) vs. 28.14(23.06) ml/min/1.73 m², p < 0.05]. In addition, ABCC8 rs3758947 was associated with higher albumin-to-creatinine ratios [193.5(1139.91) vs. 160(652.90) mg/g, p < 0.05]. The epistasis analysis of SNP-pairs interactions showed that ABCC8 rs3758947 interacted with several SNPs in SLC2A2 to significantly affect CV events (p < 0.01). No SNPs were associated with DN risk.

CONCLUSIONS

Polymorphisms in genes determining glucose homeostasis may play a relevant role in renal parameters and CV-related outcomes of DN patients.

Tag-SNPs in Phospholipase-Related Genes Modify the Susceptibility to Nephrosclerosis and its Associated Cardiovascular Risk

Nephrosclerosis patients have a high cardiovascular (CV) risk that is very often of more concern than the renal disease itself. We aimed to determine whether variants in phospholipase-related genes, associated with atherosclerosis and CV outcomes in the general population, could constitute biomarkers of nephrosclerosis and/or its associated CV risk. We screened 1,209 nephrosclerosis patients and controls for 86 tag-SNPs that were identified in the SCARB1, PLA2G4A, and PLA2G7 gene loci. Regression models were utilized to evaluate their effect on several clinical parameters. Most notably, rs10846744 and rs838880 in SCARB1 showed significant odds ratios (OR) of 0.66 (0.51–0.87), p = 0.003 and 1.48 (1.11–1.96), p = 0.007 for nephrosclerosis risk. PLA2G4A and PLA2G7 harboured several SNPs associated with atherosclerosis measurements in the patients, namely common carotid intima media thickness (ccIMT), presence of plaques, number of plaques detected and 2-years ccIMT progression (significant p-values ranging from 0.0004 to 0.047). Eight SNPs in PLA2G4A were independent risk factors for CV events in nephrosclerosis patients. Their addition to a ROC model containing classic risk factors significantly improved its predictive power from AUC = 69.1% (61.4–76.9) to AUC = 79.1% (73.1–85.1%), p = 0.047. Finally, PLA2G4A rs932476AA and rs6683619AA genotypes were associated with lower CV event-free survival after controlling for confounding variables [49.59 (47.97–51.21) vs. 51.81 (49.93–51.78) months, p = 0.041 and 46.46 (41.00–51.92) vs. 51.17 (50.25–52.08) months, p = 0.022, respectively]. Variability in phospholipase-related genes play a relevant role in nephrosclerosis and associated atherosclerosis measurements and CV events.

Body Fat Distribution, Adipocytokines Levels and Variability in Associated Genes and Kidney Transplant Outcomes

Introduction: Body fat distribution is known to contribute to a variety of pathologies. Research Questions: We aimed to assess whether this distribution is associated with clinical outcomes in renal transplant recipients (RTR) and to examine its relationship with leptin and adiponectin gene variants and plasma concentrations. Design: Bioelectrical impedance analyses were performed in 236 RTR. Leptin/adiponectin levels were measured by immunoassay and relevant polymorphisms in the leptin receptor (LEPR) and adiponectin (ADIPOQ) genes were identified. Associations were assessed by logistic regression modeling. Results: The waist-to-height ratio (WHr) displayed a significant association with delayed graft function, acute rejection and post-transplant diabetes mellitus, with OR values of 2.04 (1.02-4.08) p = 0.045; 3.08 (1.22-7.79) p = 0.017 and 2.79 (1.16-6.74) p = 0.022, respectively. Waist circumference was linked to delayed graft function [OR = 1.03 (1.01-1.05), p = 0.025] and AR [OR = 1.041 (1.01-1.07), p = 0.009]. Leptin levels were significantly higher in patients who experienced rejection [19.91 ± 23.72 versus 11.22 ± 16.42 ng/ml; OR = 1.021 (1.01-1.04), p = 0.017]. The ADIPOQ rs1501299TT genotype showed a significant association with higher WHr (0.63 ± 0.11 vs 0.59 ± 0.87 for GG/GT genotypes; p = 0.015) and WC values (102.3 ± 14.12 vs 96.38 ± 14.65 for GG/GT genotypes; p = 0.021). Conclusion: WC, and especially WHr, are associated with adverse outcomes in renal transplantation and are affected by variability in the ADIPOQ gene.

Genetic Variants in PGE2 Receptors Modulate the Risk of Nephrosclerosis and Clinical Outcomes in These Patients

Prostaglandin E2 (PGE2) is a major actor mediating renal injury. We aimed to determine genetic variability in the genes coding for its receptors (PTGER1-4) and study associations with nephrosclerosis risk and clinical outcomes. We identified 96 tag-SNPs capturing global variability in PTGER1-4 and screened 1209 nephrosclerosis patients and controls. The effect of these variants was evaluated by multivariate regression analyses. Two PTGER3 SNPs, rs11209730 and rs10399704, remained significant in a backward elimination regression model with other non-genetic variables (OR = 1.45 (1.07-1.95), p = 0.016 and OR = 0.71 (0.51-0.99), p = 0.041, respectively). In the nephrosclerosis patients, a proximal region of PTGER3 was tagged as relevant for eGFR (p values for identified SNPs ranged from 0.0003 to 0.038). Two consecutive PTGER3 SNPs, rs2284362 and rs2284363, significantly decreased systolic (p = 0.005 and p = 0.0005), diastolic (p = 0.039 and p = 0.005), and pulse pressure values (p = 0.038 and 0.014). Patients were followed for a median of 47 months (7-54) to evaluate cardiovascular (CV) risk. Cox regression analysis showed that carriers of the PTGER1rs2241360 T variant had better CV event-free survival than wild-type individuals (p = 0.029). In addition, PTGER3rs7533733 GG carriers had lower event-free survival than AA/AG patients (p = 0.011). Our results indicate that genetic variability in PGE2 receptors, particularly EP3, may be clinically relevant for nephrosclerosis and its associated CV risk.

Plasma and urinary concentrations of arachidonic acid-derived eicosanoids are associated with diabetic kidney disease

Preclinical studies indicate that arachidonic acid (AA)-derived eicosanoids contribute to hyperglycemia-induced kidney injury. We aimed to determine whether plasma and/or urinary levels of dihydroxyeicosatrienoic (DHETs) and 20-hydroxyeicosatetraenoic (20-HETE) acids are associated with diabetic kidney disease (DKD). A total of 334 subjects (132 DKD patients and 202 non-diabetic individuals) were studied. Plasma levels of 11,12-DHET, 14,15-DHET and 20-HETE were measured by LC/MS/MS. Urinary 20-HETE concentrations were determined by immunoenzymatic assay. Subjects with normoalbuminuria had larger 20-HETE-to-creatinine urinary ratios (20-HETE/Cr) than those with micro and macroalbuminuria (p=0.012). Likewise, participants with eGFR>60 ml/min/1.73 m² had higher plasma levels of 14,15-DHET (p=0.039) and 20-HETE/Cr ratios (p=0.007). Concentrations of 14,15-DHET, 11,12-DHET and 20-HETE/Cr were significantly lower in DKD patients. Median values for non-diabetic vs. DKD were, respectively, 493 (351.0-691.5) vs. 358 (260.5-522) ng/L, p=3e-5; 262 (183.5-356.0) vs. 202 (141.5-278.0) ng/L, p=1e-4 and 5.26 (1.68-11.65) vs. 2.53 (1.01-6.28) ng/mgCr, p=0.010. In addition, 20-HETE/Cr ratios were higher in patients with non-proteinuric DKD than in those with typical DKD (p=0.020). When only individuals with impaired filtration were considered, 14,15-DHET and 11,12-DHET levels were still higher in non-diabetic subjects (p=0.002 and p=0.006, respectively). Our results indicate that AA-derived eicosanoids may play a relevant role in DKD.

Variants in the Obesity-Linked FTO gene locus modulates psychopathological features of patients with Anorexia Nervosa

Our aim was to determine whether variability in the fat mass obesity (FTO) gene locus, consistently related to obesity, affects the risk of eating disorders (ED) and/or the psychopathology displayed by these patients. We analyzed 26 tag-single nucleotide polymorphisms (SNPs) that capture FTO variability in 352 ED patients [233 with Anorexia Nervosa (AN) and 119 with binge-eating] and 396 controls. Psychopathological symptoms and traits were evaluated by the Eating Disorders Inventory Test 2 (EDI-2) and Symptoms Checklist 90 Revised (SCL-90R) questionnaires. No associations were found for ED risk. The rs7205987 CC genotype correlated with higher scores in all but one of the EDI-2 scales in the AN group. Associations with Bulimia (p = 0.0019) and Interoceptive Awareness (p = 0.00007) retained significance after False Discovery Rate (FDR) correction for multiple testing. A 3-SNP sliding window analysis showed that FTO haplotypes were again highly associated with Interoceptive Awareness (rs9921255/rs6499662/rs7205987 haplotype; FDR-q = 0.04), Bulimia (rs1125338/rs2192872/rs708258; FDR-q = 0.00037), and Maturity Fears (rs708258/rs12599672/rs11076017; FDR-q = 0.041). In addition, a distal region of the gene between rs9924877 (position 53947509) and rs2192872 (54040715) was linked to Anxiety, Depression and Phobic Anxiety in AN patients, with FDR-q values ranging from 0.023 to 0.045. The results suggest that the FTO gene might be an important locus regarding traits and psychopathological symptoms often displayed by AN patients.

Genetic variants in dopamine pathways affect personality dimensions displayed by patients with eating disorders

PURPOSE

We aimed to analyze the association between common polymorphisms in dopamine pathways with personality dimensions frequently present in patients with eating disorders (ED).

METHODS

A total of 324 patients [210 with anorexia nervosa (AN), 80 with bulimia nervosa (BN) and 34 with binge-eating disorder (BED)] were diagnosed according to DSM-5 criteria and interviewed using the EDI 2 and SCL-90R questionnaires at the eating disorders unit. Blood samples were drawn and the DNA screened for polymorphisms in dopamine receptor genes (DRD2 A2/A1 and DRD3 Ser9Gly) and in the dopamine transporter DAT1 10R/9R.

RESULTS

AN patients who carried the DRD3 Gly9Gly genotype displayed significantly higher EDI-2 total scores than patients with the Ser9 allele (118.09 ± 8.75 vs. 97.23 ± 2.73, p = 0.010). In these patients, Gly9Gly carriers also showed higher scores in all the individuals' EDI-2 scales. Differences were especially relevant for bulimia (p = 0.004), ineffectiveness (p = 0.044), interpersonal distrust (p = 0.037), interoceptive awareness (p = 0.006) and maturity fears (p = 0.038). Epistasis analyses showed a strong effect of the interaction between DRD3 Ser9Gly and DRD2 A2A1 on the bulimia (p < 0.05), ineffectiveness (p < 0.05) and asceticism (p < 0.01) scales, as well as on the EDI-2 total score (p < 0.05). The scores of the SCL-90R inventory were largely unaffected by the presence of the polymorphisms.

CONCLUSION

Whilst no associations were found for the BN and BED groups, our results suggest that women with AN carrying the homozygous variant Gly9Gly genotype in the dopamine D3 receptor have significantly worse ED-related symptomatology.

LEVEL OF EVIDENCE

Level III (evidence obtained from well-designed cohort or case-control analytic studies).

Sacubitril-Valsartan Improves Anemia of Cardiorenal Syndrome (CRS)

BACKGROUND AND AIMS

Anemia is a common complication of heart failure and Chronic Kidney Disease (CKD). Sacubitril-valsartan is a novel therapy for the treatment of chronic Heart Failure with a reduced Ejection Fraction (HFrEF). We have evaluated the short-term effects of sacubitril- valsartan on the anemia of CRS.

METHODS

The study group comprised 39 patients with HFrEF, who were followed-up for three months. The study is a retrospective analysis of clinical data. Data of 3 months' and baseline visits were recorded including plasmatic creatinine, glomerular filtration rate, cystatin C, kaliemia, haemoglobin, pro-BNP, and albuminuria.

RESULTS

In all, 34 patients ended the follow-up. Mean sacubitril-valsartan dosage at baseline was 101 ± 62 mg/day and 126 ± 59 mg/day at end. Mean hemoglobin increased from 12.2 ± 1.1 g/dl at baseline to 12.9 ± 1.0 g/dl (p = 0.001,). Prevalence of anemia was 64.7% (95%CI, 47.9-78.5%) at baseline and 38.4 (95%CI, 23.9-55.0%) after the follow-up (p = 0.016). Serum cystatin C levels decreased from 2.71 ± 1.0 to 2.48 ± 1.0 mg/l (p = 0.028). Serum K levels remained unchanged (baseline 4.94 ± 0.60, three months visit 4.94 ± 0.61 mmol/l, p = 0.998).

CONCLUSION

Sacubitril-valsartan improves anemia in CRS patients. An improvement in serum cystatin levels was observed. Few untoward effects were detected. These findings should be confirmed in wider clinical trials.

Combined donor-recipient genotypes of leptin receptor and adiponectin gene polymorphisms affect the incidence of complications after renal transplantation

Background

We aimed to examine whether combined donor/recipient variants in the leptin receptor (LEPR) and adiponectin (ADIPOQ) genes may affect outcomes in renal transplantation.

Methods

A total of 233 donors and their corresponding 307 recipients were genotyped for LEPR rs1805094, rs1137100 and rs1137101, and ADIPOQ rs1501299 and rs224176. Combined donor/recipient genetic scores were created to investigate associations with delayed graft function (DGF), graft loss and estimated glomerular filtration rate (eGFR).

Results

Recipients whose donors carried variant alleles of LEPR rs1137100 and rs1137101 had lower risk of DGF [OR = 0.48 (0.24–0.97), p = 0.040] and [OR = 0.47 (0.23–0.95), p = 0.035], respectively. In addition, rs1137101 also showed an inverse association with lower incidence of graft loss [OR = 0.44 (0.31–0.97), p = 0.040]. The analysis of genetic scores of donor/recipients showed that again rs1137101 was inversely associated with both outcomes: OR = 0.46 (0.23–0.92), p = 0.029 and OR = 0.45 (0.11–0.81), p = 0.009, respectively. With regard to graft function, the T-allele of ADIPOQ rs1501299 in the donor was related to higher eGFR values (75.26 ± 29.01 vs. 67.34 ± 25.39 ml/min for wild-type grafts, p = 0.012). Higher combined genetic scores in this same polymorphism were also associated with better function (78.33 ± 31.87 vs. 68.25 ± 24.32 ml/min, p = 0.018). Finally, eGFR values were similar between paired kidneys but they were different when comparing grafts with or without the rs1501299 T-variant (77.87 ± 26.50 vs. 69.27 ± 26.73 ml/min, p = 0.016).

Conclusions

Our study has shown for the first time to our knowledge that variants in LEPR and ADIPOQ genes of the donors and/or their combination with those in the recipients may affect the outcome of renal transplantation.

Association of polymorphisms in leptin and adiponectin genes with long-term outcomes in renal transplant recipients

The effect of polymorphims in leptin and adiponectin genes on long-term outcomes of renal transplantation is unknown. In 349 renal transplant recipients (RTR), we aimed to determine associations between five SNPs in the leptin receptor (LEPR) and adiponectin (ADIPOQ) genes and these outcomes. Follow-up time ranged from 2 to 25 years (mean 10.29 ± 5.16 years). Two SNPs showed associations with long-term outcomes and their statistical significance greatly increased after 39 RTR with a history of cardiovascular events prior to transplantation were removed from the analysis. Adjusted odds ratios (OR) for LEPR rs1805094 and ADIPOQ rs1501299 and risk of graft loss were 0.35 (0.16-0.74) p = 0.006 and 2.37 (1.28-4.37) p = 0.006, respectively. The assessment of risk for global mortality revealed OR values of 0.20 (0.06-0.62), p = 0.005, and 2.43 (1.08-5.44), p = 0.031 for LEPR rs1805094 and ADIPOQ rs1501299, respectively. Our results show that polymorphism in genes involved in leptin and adiponectin function modify long-term outcomes in renal transplantation.

Association of COMT Val158Met Polymorphism with Psychopathological Symptoms in Patients with Eating Disorders

BACKGROUND

Dopamine physiological functions make dopaminergic genes suitable candidates for association studies in eating disorders (ED). A Val158Met polymorphism in the catechol-O-methyltransferase (COMT) gene, which is involved in dopamine degradation, has been studied in relation to ED.

OBJECTIVE

We aimed to analyze the association between this polymorphism and general psychopathological symptoms that are often coupled to these disorders.

METHOD

A total of 303 ED patients, diagnosed according to DSM-5 criteria, completed the SCL-90R questionnaire and were genotyped for the Val158Met polymorphism.

RESULTS

There were significant differences in the global indices of the SCL-90R inventory between the three ED groups (Anorexia Nervosa (AN), Bulimia Nervosa (BN) and binge-eating disorder; ANOVA-p < 0.05). Females with BN showed the highest scores (worse symptomatology) of all participants. In this group, a gene-dose effect was observed on the psychometric evaluation of the patients, as Val/Val carriers displayed the highest scores for all the SCL-90R scales, followed by Val/Met and then Met/Met carriers. Significant differences between genotypes were observed in the Obsessive- Compulsive (p = 0.018), Paranoid Ideation (p = 0.0005) and Psychoticism (p = 0.039) scales, as well as in the PSDI (p = 0.014) general index.

CONCLUSION

The results taken together suggest that COMT genetic variability may contribute to general psychopathological symptoms in patients with BN.

Clinical Implications of Methotrexate Pharmacogenetics in Childhood Acute Lymphoblastic Leukaemia

Background:

In the past two decades, a great body of research has been published regarding the effects of genetic polymorphisms on methotrexate (MTX)-induced toxicity and efficacy. Of particular interest is the role of this compound in childhood acute lymphoblastic leukaemia (ALL), where it is a pivotal drug in the different treatment protocols, both at low and high doses. MTX acts on a variety of target enzymes in the folates cycle, as well as being transported out and into of the cell by several transmembrane proteins.

Methods:

We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question.

Results:

This review has intended to summarize the current knowledge concerning the clinical impact of polymorphisms in enzymes and transporters involved in MTX disposition and mechanism of action on paediatric patients with ALL.

Conclusion:

In this work, we describe why, in spite of the significant research efforts, pharmacogenetics findings in this setting have not yet found their way into routine clinical practice.

Variability in the leptin receptor gene and other risk factors for post-transplant diabetes mellitus in renal transplant recipients

Aim: Post-transplant diabetes mellitus (PTDM) is one of the main complications after kidney transplantation. It is known that leptin plays an important role in glucose metabolism and mutations in the leptin receptor gene (LEPR) are responsible for different complications in renal transplant recipients. We aimed to analyse the association of polymorphisms in LEPR with the development of PTDM in these patients. Methods: A total of 315 renal transplant recipients were genotyped for the Lys109Arg, Gln223Arg and Lys656Asn polymorphisms. The impact of these genetic variables together with other clinical and demographic parameters on PTDM risk was evaluated in a multivariate regression analysis. Results: The 223Arg variant showed a significant association with PTDM risk [OR = 3.26 (1.35-7.85), p = 0.009] after correcting for multiple testing. Carriers of this variant also showed higher BMI values (26.95 ± 4.23) than non-carriers (25.67 ± 4.43, p = 0.025). In addition, it was BMI at transplant and not the BMI increment in the first year after grafting that was associated with PTDM (p > 0.00001). Haplotype analyses did not reveal significant associations. Conclusions: Our result show, for the first time to our knowledge, that genetic variability in the LEPR may contribute significantly to the risk for PTDM in renal transplant recipients. KEY MESSAGES The LEPR Gln223Arg polymorphism significantly contributes to the development of PTDM in renal transplant recipients. The effect of the 223Arg variant on PTDM is strongly modulated by the age of the recipient. The 223Arg variant in the leptin receptor is related to higher BMI in renal transplant recipients.

Polymorphisms in genes involved in vasoactive eicosanoid synthesis affect cardiovascular risk in renal transplant recipients

OBJECTIVE

Arachidonic acid metabolism by cytochrome P450 (CYP) epoxygenases leads to epoxyeicosatrienoic acids (EETs), which are eicosanoids with vasodilator and anti-inflammatory properties. We aim to determine whether genetic variability in these routes may contribute to cardiovascular (CV) risk in renal transplant recipients.

METHODS

In a cohort of 355 patients, we determined the presence of two polymorphisms, CYP2C8*3 and CYP2J2*7, known to affect eicosanoid levels. Associations with CV mortality, CV event-free long-term survival and graft survival were retrospectively investigated by logistic regression models.

RESULTS

CYP2J2*7 showed a statistical trend towards higher CV mortality (p = .06) and lower cardiac or cerebral event-free long-term survival (p = .05), whilst CYP2C8*3 displayed a significant inverse association with the risk of CV event (hazard ratio [HR] = 0.34 [0.15-0.78], p = .01). The association of CYP2J2*7 with CV mortality became significant when the analysis was restrained to 316 patients without a history of CV events prior to transplantation (HR = 15.72 [2.83-91.94], p = .005). In this subgroup of patients both single nucleotide polymorphisms (SNPs) were significantly associated with event-free survival. HR values were 5.44 (1.60-18.51), p = .007 and 0.26 (0.09-0.75), p = .012 for CYP2J2*7 and CYP2C8*3, respectively.

CONCLUSIONS

Our results show, for the first time to our knowledge, that two SNPs in CYP2C8 and CYP2J2, which synthesize EETs, may modify CV outcomes in renal transplant recipients, a population that is already at a high risk of suffering these events.

Influence of TFAP2B and KCTD15 genetic variability on personality dimensions in anorexia and bulimia nervosa

INTRODUCTION

TFAP2B and KCTD15 are obesity-related genes that interact to regulate feeding behavior. We hypothesize that variability in these loci, isolated or in combination, could also be related to the risk of eating disorders (ED) and/or associated psychological traits.

METHODS

We screened 425 participants (169 ED patients, 75 obese subjects, and 181 controls) for 10 clinically relevant and tag single-nucleotide polymorphisms (SNPs) in KCTD15 and TFAP2B by the Sequenom MassARRAY platform and direct sequencing. Psychometric evaluation was performed with EDI-2 and SCL-90R inventories.

RESULTS

The KCTD15 rs287103 T variant allele was associated with increased risk of bulimia nervosa (BN) (OR = 4.34 [1.47-29.52]; p = .003) and with scores of psychopathological scales of these patients. Haplotype *6 in KCTD15 was more frequent in controls (OR = 0.40 [0.20-0.80], p = .009 for anorexia nervosa), while haplotype *4 in TFAP2B affected all three scales of the SCL-90R inventory in BN patients (p ≤ .01). Epistasis analyses revealed relevant interactions with body mass index of BN patients (p < .001). Genetic profiles in obese patients did not significantly differ from those found in ED patients.

CONCLUSIONS

This is the first study that evaluates the combined role of TFAP2B and KCTD15 genes in ED. Our preliminary findings suggest that the interaction of genetic variability in these loci could influence the risk for ED and/or anthropometric and psychological parameters.

Polymorphisms in the SNRPN gene are associated with obesity susceptibility in a Spanish population

BACKGROUND

SNRPN, which codes for the RNA-binding SmN protein, is a candidate gene for Prader-Willi syndrome. One characteristic of this neuroendocrine disorder is hyperphagia resulting in extreme obesity later in life. In the present study, we aimed to assess whether variability within this gene could be implicated in obesity susceptibility.

METHODS

A case-control study was performed including 265 unrelated patients with nonsyndromic and early-onset severe obesity, belonging to high-risk obesity families from Spanish ancestry; 184 healthy control individuals were included representative of the same genetic background and sex-matched. Forty-nine single nucleotide polymorphisms (SNPs) spanning the entire SNRPN gene were selected and genotyped using the Sequenom MassARRAY platform (Sequenom Inc., San Diego, CA, USA).

RESULTS

The four SNPs, rs12905653, rs752874, rs1391516 and rs2047433, were found to be nominally associated with obesity (p < 0.03). The diversity haplotype distribution among cases and controls identified the combination rs12905653-T/rs8028366-A/rs4028395-T as being strongly and inversely associated with obesity (odds ratio = 0.49; p = 0.0006). A genetic risk score was built based on rs12905653, rs1391516 and rs2047433 SNPs and each unit increase in genetic risk score increased the obesity risk by 49% (odds ratio = 1.49, 95% confidence interval = 1.24-1.80).

CONCLUSIONS

To our knowledge, this is the first study reporting an association between variability in the SNRPN gene and the risk of being obese. Interestingly, it was the major allele of each SNP that was found to be associated with the risk of weight gain. Further studies analyzing this locus and the possible additive deleterious capability of SNP combinations could be useful for demonstrating the development of obesity.

Polymorphisms in ABCB1 and CYP19A1 genes affect anastrozole plasma concentrations and clinical outcomes in postmenopausal breast cancer patients

AIMS

Anastrozole, an aromatase inhibitor widely used in breast cancer, has recently been indicated to be a P-glycoprotein (ABCB1) substrate. We have aimed to determine whether ABCB1 single-nucleotide polymorphisms (SNPs) can affect anastrozole plasma concentrations in these patients. In addition, we assessed the impact of SNPs in CYP19A1 and TCL1A on the development of arthralgia and cancer recurrence in our series.

METHODS

This study included 110 postmenopausal women with hormone receptor-positive breast cancer. Anastrozole plasma levels were determined by a liquid chromatography-electrospray ionization-quadrupole-time-of-flight mass spectrometry system. Patients were genotyped for SNPs in the ABCB1, TCL1A and CYP19A1 genes to search for associations with pharmacokinetic and pharmacodynamics parameters using logistic regression models.

RESULTS

Anastrozole concentrations showed an almost nine-fold interindividual variability (mean 26.95 ± 11.91 ng ml^-1 ). The ABCB1 2677-TT genotype was associated with higher plasma levels (32.22 ± 12.82 vs. 25.86 ± 11.56 ng ml^-1 for GG/GT subjects; 95% confidence interval: -12.3 to -0.40), whilst the 3435-TT genotype showed a protective effect on the risk of arthralgia (odds ratio = 0.32 [0.11-0.89]; P = 0.029). The CYP19A1 rs1008805 GG genotype was strongly and inversely associated with arthralgia (odds ratio = 0.24 [0.09-0.65], P = 0.004); however, SNPs near the TCL1A gene were not linked to this adverse effect. None of the patients who had cancer recurrence harboured the CYP19A1 rs727479 AA genotype, which, in contrast, was present in 38% of patients who did not relapse (P for trend = 0.031).

CONCLUSION

Our findings indicate that variability in anastrozole plasma levels may be attributable to the status of the ABCB1 gene locus. Furthermore, genetic variants in CYP19A1 were associated with arthralgia and cancer recurrence in our patients.

Risk factors for post-transplant diabetes mellitus in renal transplant: Role of genetic variability in the CYP450-mediated arachidonic acid metabolism

Arachidonic acid (AA) is metabolized by cytochrome P450 (CYP) enzymes to epoxyeicosatrienoic acids (EETs) and 20-hidroxyeicosatetraenoic acid (20-HETE), which play an important role both in renal transplant and diabetes mellitus (DM). We searched for associations between polymorphisms in this metabolic pathway and the risk of post-transplant diabetes mellitus (PTDM) in kidney recipients. One-hundred-sixty-four patients were genotyped for common SNPs in this route, namely CYP2C8*3, CYP2C8*4, CYP2C9*2, CYP2C9*3, CYP2J2*7, CYP4A11 F434S and CYP4F2 V433M. Demographic and clinical parameters were retrospectively collected at four time-points in the first year after grafting. Thirty-four patients (20.73%) developed PTDM, which was more prevalent among older patients [OR for older age = 1.06 (1.03-1.10), p < 0.001] and in those with higher body mass index (BMI) [OR for higher average BMI in the first year = 1.13 (1.04-1.23); p < 0.01]. Creatinine clearance [OR = 0.97 (0.95-0.99); p < 0.01] and exposure to tacrolimus [OR = 3.25 (1.15-9.19); p < 0.05] were also relevant for PTDM risk. With regard to genetic variants, logistic regression analysis controlling for significant demographic and clinical variables showed that the V433M polymorphism in CYP4F2, responsible for 20-HETE synthesis, was an independent risk factor for PTDM [OR = 3.94 (1.08-14.33); p < 0.05]. We have shown that a genetic variant in the CYP4F2 gene, the main gene implicated in 20-HETE synthesis, is associated with the risk for PTDM. Our findings suggest that genes in the metabolic pathways of AA may become good candidates in genetic association studies for PTDM.

Polymorphisms in CYP-mediated arachidonic acid routes affect the outcome of renal transplantation

BACKGROUND

Arachidonic acid (AA) is metabolized by cytochrome P450 (CYP) enzymes to vasoactive metabolites (mainly epoxyeicosatrienoic acids) which are known to play a protective role against damaging processes that may occur after re-oxygenation of the graft. We aimed to investigate whether the presence of functional polymorphisms along these metabolic routes may play a role in the outcome of renal transplantation.

DESIGN

One-hundred and forty Caucasian renal transplant recipients and 137 donors were included. We determined the presence of seven common functional polymorphisms in the five genes governing the CYP-mediated AA metabolic pathway (CYP2C8, CYP2C9, CYP2J2, CYP4A11 and CYP4F2). Associations with parameters and events related to graft function and survival were retrospectively investigated throughout the first year after grafting.

RESULTS

The CYP2J2*7 allele of the donor was significantly associated with higher risk for delayed graft function [OR = 4·40 (1·45-13·37), P < 0·01] and lower death-censored graft survival [107·90 (84·19-131·62) vs. 176·89 (166·47-187·32) months for CYP2J2*1/*1 grafts; log-rank P = 0·015]. In addition, patients whose donors carried the CYP4A11 434S variant of the F434S polymorphism displayed impaired creatinine clearance, with statistically significant differences vs. 434FF subjects throughout the whole period of study (P < 0·05, P < 0·01, P < 0·001 and P < 0·05 for 1 week, 1 month, 5 months and 1 year after grafting, respectively).

CONCLUSIONS

Taken together, these results indicate that variability in the CYP450 genes involved in the synthesis of eicosanoids from AA may have a significant impact on graft function and survival in renal transplantation.

A 3'-UTR Polymorphism in Soluble Epoxide Hydrolase Gene Is Associated with Acute Rejection in Renal Transplant Recipients

Background and Purpose

Epoxyeicosatrienoic acids (EETs) are arachidonic acid metabolites that play a protective role against damaging processes that may occur after re-oxygenation of the graft. We aimed to investigate whether the presence of functional polymorphisms in the gene encoding soluble epoxy hydrolase (EPHX2), which metabolizes EETs to less active compounds, may play a role in the outcome of renal transplantation.

Methods

In a group of 259 Caucasian renal transplant recipients and 183 deceased donors, we determined the presence of three common EPHX2 SNPs, namely rs41507953 (K55R), rs751141 (R287Q) and rs1042032 A/G. Associations with parameters of graft function and the incidence of acute rejection were retrospectively investigated throughout the first year after grafting by logistic regression adjusting for clinical and demographic variables.

Results

Carriers of the rs1042032 GG genotype displayed significantly lower estimated glomerular filtration rate (eGFR) (38.15 ± 15.57 vs. 45.99 ± 16.05; p = 0.04) and higher serum creatinine values (1.57 ± 0.58 vs. 1.30 ± 0.47 g/dL; p=0.02) one year after grafting, compared to patients carrying the wildtype A-allele. The same GG genotype was also associated to increased risk of acute rejection. Interestingly, this association was observed for the genotype of both recipients [OR =6.34 (1.35-29.90); p = 0.015] and donors [OR = 5.53 (1.10-27.80); p=0.042]. A statistical model including both genotypes along with other meaningful demographic and clinical variables resulted in an increased significance for the association with the recipients’ genotype [OR=8.28 (1.21-74.27); p=0.031].

Conclusions

Our results suggest that genetic variability in the EETs-metabolizing gene, EPHX2, may have a significant impact on the outcome of deceased-donor renal transplantation.

Discussing the putative role of obesity-associated genes in the etiopathogenesis of eating disorders

In addition to the identification of mutations clearly related to Mendelian forms of obesity; genome-wide association studies and follow-up studies have in the last years pinpointed several loci associated with BMI. These genetic alterations are located in or near genes expressed in the hypothalamus that are involved in the regulation of eating behavior. Accordingly, it seems plausible that these SNPs, or others located in related genes, could also help develop aberrant conduct patterns that favor the establishment of eating disorders should other susceptibility factors or personality dimensions be present. However, and somewhat surprisingly, with few exceptions such as BDNF, the great majority of the genes governing these pathways remain untested in patients with anorexia nervosa, bulimia nervosa or binge-eating disorder. In the present work, we review the few existing studies, but also indications and biological concepts that point to these genes in the CNS as good candidates for association studies with eating disorder patients.

Clinical relevance of erythrocyte ferritin in microcytic anemias

BACKGROUND

Erythrocyte ferritin (EF) reflects the balance between iron supply and its utilization for hemoglobin synthesis. This balance is altered in microcytosis. We aimed to evaluate the diagnostic value of both EF and the ratio (FRR) plasma ferritin (PF)/EF in these disorders.

METHODS

A total of 231 subjects participated in the study. Samples from 93 adult patients with different causes of microcytosis, 57 healthy subjects and 81 full-term newborns were analyzed to determine EF and PF concentrations and other hematological parameters.

RESULTS

In patients with iron deficiency, and in contrast to PF, EF decreased only in the presence of anemia and in direct correlation with the degree of microcytosis (Pearson's p<0.001). EF values for thalassemia patients were higher than those observed in controls (p<10e-5), while PF concentrations were similar between these groups. This EF increase was more marked in the delta-beta thalassemia group (p<0.05). Finally, FRR was much higher in patients with anemia of inflammation than in those with thalassemia (p<10e-5), thus helping to discriminate between these disorders.

CONCLUSIONS

EF and FRR are tools that may be useful in the diagnosis of the main causes of microcytosis.

Functional consequences of transferrin receptor-2 mutations causing hereditary hemochromatosis type 3

Hereditary hemochromatosis (HH) type 3 is an autosomal recessive disorder of iron metabolism characterized by excessive iron deposition in the liver and caused by mutations in the transferrin receptor 2 (TFR2) gene. Here, we describe three new HH type 3 Spanish families with four TFR2 mutations (p.Gly792Arg, c.1606-8A>G, Gln306*, and Gln672*). The missense variation p.Gly792Arg was found in homozygosity in two adult patients of the same family, and in compound heterozygosity in an adult proband that also carries a novel intronic change (c.1606-8A>G). Two new nonsense TFR2 mutations (Gln306* and Gln672*) were detected in a pediatric case. We examine the functional consequences of two TFR2 variants (p.Gly792Arg and c.1606-8A>G) using molecular and computational methods. Cellular protein localization studies using immunofluorescence demonstrated that the plasma membrane localization of p.Gly792Arg TFR2 is impaired. Splicing studies in vitro and in vivo reveal that the c.1606-8A>G mutation leads to the creation of a new acceptor splice site and an aberrant TFR2 mRNA. The reported mutations caused HH type 3 by protein truncation, altering TFR2 membrane localization or by mRNA splicing defect, producing a nonfunctional TFR2 protein and a defective signaling transduction for hepcidin regulation. TFR2 genotyping should be considered in adult but also in pediatric cases with early-onset of iron overload.

Impact of NEGR1 genetic variability on psychological traits of patients with eating disorders

Genetics variants in the NEGR1 gene, strongly expressed in the brain, have been reported to affect the neuronal control of food intake therefore inducing obesity. With the same rationale, we hypothesized that this genetic variability may be associated with psychological traits commonly displayed by eating disorder (ED) patients and/or with the risk for the disorder. We analyzed 21 tag-single-nucleotide polymorphisms (SNPs) in the coding sequence and adjacent regions of the NEGR1 gene. A total of 169 ED patients (106 with anorexia nervosa (AN) and 63 with bulimia nervosa (BN)) and 312 healthy subjects were genotyped. Personality traits and general psychopathological symptoms were assessed by the Eating Disorders Inventory Test-2 (EDI-2) and Symptom Checklist 90 Revised inventories. None of the SNPs or haplotypes analyzed were associated with a greater risk of ED or correlated with anthropometric parameters. However, in patients with BN, four SNPs (rs12740031, rs10789322, rs6659202 and rs591540) correlated with the scores in Drive for Thinness (DT), Ineffectiveness (I) and Interoceptive Awareness (IA) (Bonferroni-P<0.05 in all instances). The first two SNPs along with rs954299 and rs2422021 formed a haplotype block, which showed a consistent association with the EDI-2 score in BN patients (Bonferroni-P=0.01). A subsequent three-SNP sliding-window approach identified a central area, encompassing both the haplotype block and the individually relevant SNPs that strongly correlated with the scores of BN patients in DT, I, IA and Bulimia. No associations were identified in the AN group. These preliminary results indicate that NEGR1 could be an important locus influencing certain personality dimensions in BN patients.

Diagnostic and therapeutic challenges of primary autoimmune haemolytic anaemia in children

Autoimmune haemolytic anaemias (AIHAs) are extracorpuscular haemolytic anaemias produced by antierythrocyte autoantibodies which cause a shortened red blood cell life span. There are several reasons why the diagnosis and treatment of AIHAs in children represent a bigger challenge than in adult patients, including the presence of particular AIHA types, the uncertainty of serological tests and the limited clinical experience. All these facts have added up to a poor understanding and management of some topics in childhood AIHA. We discuss some of these questions, for example, the occurrence of AIHA with negative direct antiglobulin (Coombs) test, the correct diagnosis and actual incidence of paroxysmal cold haemoglobinuria, the most appropriate second-line therapy of AIHA in childhood or the management of transfusion procedures in these patients. This review takes a practical point of view, providing with some ground rules on how to identify and deal with these paediatric patients.

Influence of dopamine polymorphisms on the risk for anorexia nervosa and associated psychopathological features

Dopamine neuronal functions make polymorphisms in dopaminergic pathways good candidates for playing a relevant role in anorexia nervosa (AN) and related psychopathological features. We have analyzed the effect of 8 polymorphisms in genes coding for dopamine receptors (DRD2, DRD3, and DRD4), transporters (DAT1) and metabolizing enzymes (COMT) in 78 women with AN and 186 control subjects. Associated psychopathological characteristics in patients with AN were assessed by the Eating Disorders Inventory Test-2 and SCL-90R self-reported questionnaires. The DRD4 variable number of tandem repeats (VNTR) 7R/7R and DRD4 -616CC genotypes were significantly associated with a greater risk for AN (odds ratio, 3.83; confidence interval, 1.05-13.98; P = 0.04; and odds ratio, 1.74; confidence interval, 1.01-2.97; P = 0.03, respectively). The analysis of physiological parameters in the patients with AN revealed that the short allele of a 120-base pair tandem repeat in the promoter region of the DRD4 gene was associated with higher weight (48.35 ± 6.79 vs 43.95 ± 5.78 kg; Bonferroni, P < 0.05), whereas the DRD4 -521TT genotype was associated with significantly higher body mass index (17.29 ± 2.25 vs 18.13 ± 2.41 kg/m2; Bonferroni, P < 0.05). The DRD4 C-616G and DAT1 VNTR polymorphisms correlated with several psychopathological features in patients with AN. Carriers of the mutant homozygous genotypes scored higher in all but one of the Eating Disorders Inventory Test-2 subscales. After correction for multiple testing, differences in Asceticism scores between DAT1 VNTR genotypes, as well as differences in Drive for Thinness and Body Dissatisfaction between C-616G genotypes remained significant (P < 0.05). The results show that certain genetic alterations in the dopamine pathways are able to modify the risk for AN as well as modulate psychopathological features that are often coupled to this disorder.

Haplotypes in the 5'-untranslated region of the CYP1A2 gene are inversely associated with lung cancer risk but do not correlate with caffeine metabolism

In this study, we analyzed the influence of CYP1A2 genetic variation and enzyme activity on lung cancer risk in a high-incidence area. A total of 95 lung cancer patients and 196 controls were genotyped for the -3860G/A, -3113A/G, -2467T/delT, -739T/G, and -163C/A polymorphisms in the 5'-untranslated region of the gene. In addition, a subset of 70 patients and 115 controls were phenotyped by high-performance liquid chromatography determination of the caffeine metabolic ratio (CMR). The -2467T/delT polymorphism and the CYP1A2*1V haplotype (-163C>A, -2467T>delT) were inversely associated with lung cancer risk (odds ratio [OR] = 0.47 [0.2-0.9]; P = 0.02 and OR = 0.13 [0.02-1.0]; P = 0.04; respectively). In addition, the CYP*1A/*1V and *1F (-163C>A)/*1D (-163C>A, -2467T>delT) diplotypes were absent in the patients group, whereas accounting for 7.1% (P = 0.017) and 5.6% (P = 0.037) of controls, respectively. Mean CMR was significantly higher in patients than in controls (10.50 ± 17.31 vs. 6.52 ± 6.26, P = 0.01) but regression analyses did not yield significant ORs for the association with lung cancer risk. Similarly, no significant correlations were found between any genetic variant and enzyme activity. Several CYP1A2 haplotypes and diplotypes containing the -2467delT variant were associated with lower lung cancer risk; however, they did not correlate with significant changes in CYP1A2 metabolic activity toward caffeine.

CYP2C8*3 polymorphism and donor age are associated with allograft dysfunction in kidney transplant recipients treated with calcineurin inhibitors

Epoxieicosatrienoic acids (EETs) play a protective role against damaging processes in the kidney. We have assessed the effect of polymorphisms in EETs-producing enzymes (CYP2C8 and CYP2J2) and other proteins involved in calcineurin inhibitors (CNIs) disposition (CYP3A4, CYP3A5, and ABCB1) on graft function and clinical outcome in 166 renal transplant recipients treated with CNIs. Both CYP2C8*3 and donor age greater than 48 years were associated to a higher incidence of delayed graft function (DGF) [OR = 2.01 (1.1-4.1), P = .04 and 5.14 (2.4-10.9), P < .0001; respectively] and worse creatinine clearance 1 year after grafting (P < .05 and P < .001, respectively). In addition, carrying 4-6 variants in the 3 ABCB1 loci and older donor age were individually associated to higher incidence of calcineurin-inhibitor-induced nephrotoxicity [OR = 2.38 (1.1-5.4), P = .03 and OR = 1.03 (1.01-1.06), P = .038]. Regression analyses confirmed the relevant effect of both CYP2C8*3 and donor age on graft dysfunction. Carrying the 2C8*3 allele and having a donor older than 48 years was defined as a high-risk status and observed to be highly related to DGF [OR = 3.91 (1.46-10.48), P < .01] and worse creatinine clearance (P = .033). Our results show that genetic and clinical parameters can be combined to identify risk factors for allograft dysfunction in renal transplant recipients.

Toward a clinical practice guide in pharmacogenomics testing for functional polymorphisms of drug-metabolizing enzymes. Gene/drug pairs and barriers perceived in Spain

The development of clinical practice recommendations or guidelines for the clinical use of biomarkers is an issue of great importance with regard to adverse drug reactions. The potential of pharmacogenomic biomarkers has been extensively investigated in recent years. However, several barriers to implementing the use of pharmacogenomics testing exist. We conducted a survey among members of the Spanish Societies of Pharmacology and Clinical Pharmacology to obtain information about the perception of such barriers and to compare the perceptions of participants about the relative importance of major gene/drug pairs. Of 11 potential barriers, the highest importance was attributed to lack of institutional support for pharmacogenomics testing, and to the issues related to the lack of guidelines. Of the proposed gene/drug pairs the highest importance was assigned to HLA-B/abacavir, UGT1A1/irinotecan, and CYP2D6/tamoxifen. In this perspective article, we compare the relative importance of 29 gene/drug pairs in the Spanish study with that of the same pairs in the American Society for Clinical Pharmacology and Therapeutics study, and we provide suggestions and areas of focus to develop a guide for clinical practice in pharmacogenomics testing.

Impact of genetic polymorphisms on chemotherapy toxicity in childhood acute lymphoblastic leukemia

The efficacy of chemotherapy in pediatric acute lymphoblastic leukemia (ALL) patients has significantly increased in the last 20 years; as a result, the focus of research is slowly shifting from trying to increase survival rates to reduce chemotherapy-related toxicity. At the present time, the cornerstone of therapy for ALL is still formed by a reduced number of drugs with a highly toxic profile. In recent years, a number of genetic polymorphisms have been identified that can play a significant role in modifying the pharmacokinetics and pharmacodynamics of these drugs. The best example is that of the TPMT gene, whose genotyping is being incorporated to clinical practice in order to individualize doses of mercaptopurine. However, there are additional genes that are relevant for the metabolism, activity, and/or transport of other chemotherapy drugs that are widely use in ALL, such as methotrexate, cyclophosphamide, vincristine, L-asparaginase, etoposide, cytarabine, or cytotoxic antibiotics. These genes can also be affected by genetic alterations that could therefore have clinical consequences. In this review we will discuss recent data on this field, with special focus on those polymorphisms that could be used in clinical practice to tailor chemotherapy for ALL in order to reduce the occurrence of serious adverse effects.

Central nervous system chemotoxicity during treatment of pediatric acute lymphoblastic leukemia/lymphoma

In the last decades, increasing success rates are being obtained in the chemotherapy of pediatric leukemia and lymphoma. However, the cornerstone of this treatment is still formed by a reduced number of drugs with a highly toxic profile. In particular, central nervous system complications remain a challenging clinical problem, requiring rapid detection and prompt treatment to limit permanent damage. Furthermore, clinicians are often challenged to discriminate between CNS involvement by the disease, toxicity of drugs or infections. This clinically oriented review will help recognize and handle the main neurologic adverse effects induced by chemotherapy in pediatric patients with lymphoblastic leukemia/lymphoma. Different clinical entities and putative drugs involved are discussed in each chapter, with clinical cases illustrating the most relevant and challenging events. In addition, specific clinical-radiological patterns of some of these neurologic events are detailed. Finally, the role of pharmacogenetics, with special focus on those polymorphisms that could help explain the occurrence of neurotoxicity, is also discussed.

Impact of genetic polymorphisms on tacrolimus pharmacokinetics and the clinical outcome of renal transplantation

We retrospectively examined the association of polymorphisms in the CYP3A, CYP2J2, CYP2C8, and ABCB1 genes with pharmacokinetic (PKs) and pharmacodynamic (PDs) parameters of tacrolimus in 103 renal transplant recipients for a period of 1 year. CYP3A5 expressers had lower predose concentrations (C(0) )/dose and higher dose requirements than nonexpressers throughout the study. Among CYP3A5*1 carriers, those also carrying the CYP3A4*1B allele showed the lowest C(0) /dose, as compared with CYP3A4*1/CYP3A5*3 carriers (54.28±26.45, 59.12±24.00, 62.43±41.12, and 57.01±17.34 vs. 112.37± 76.60, 123.21±59.57, 163.34±76.23, and 183.07±107.82 at 1 week, 1 month, 5 months, and 1 year after transplantation). In addition, CYP3A4*1B/CYP3A5*1 carriers showed significantly lower dose-corrected exposure than CYP3A4*1/CYP3A5*1 carriers 1 year after transplantation (57.01±17.34 vs. 100.09±24.78; P=0.016). Only the ABCB1 TGC (3435-2677-1236) haplotype showed a consistent association with PDs (nephrotoxicity; OR=4.73; CI: 1.3-16.7; P=0.02). Our findings indicate that the CYP3A4*1B-CYP3A5*1 haplotype may have a more profound impact in tacrolimus PKs than the CYP3A5*1 allele. This study does not support a critical role of the CYP450 or ABCB1 single nucleotide polymorphisms in the occurrence of toxicity or acute rejection in renal transplant recipients treated with tacrolimus.