Predictive factors of allosensitization in renal transplant patients switched from calcineurin to mTOR inhibitors.

Conversion of kidney-transplant recipients from calcineurin inhibitors to mTOR inhibitors has been suggested to be a risk factor for increased alloimmune response. We have analyzed the development of new HLA-antibodies (HLA-Abs) early after conversion in 184 patients converted in stable phase at our hospital and compared with a control group of nonconverted comparable 63 transplants. Using single-antigen solid-phase immunoassay analysis, a preconversion and a 3-6 months postconversion sera were prospectively analyzed in every patient for the appearance of new HLA-Abs. Renal function at 2 years postconversion and cumulative graft survival were compared between groups. In 16 patients, new HLA-Abs (3-DSA and 13-NonDSA), not present at the moment of conversion, were detected (8.7% vs. 3.1% in the control group). The type of mTORi used, type of CNI preconversion, the presence of steroids, time of conversion, or indication for conversion did not have influence on this effect but the presence of HLA-Abs before conversion highly correlated with the appearance of new specificities. Patients with de novo HLA-Abs showed a trend to worst graft function and survival. In conclusion, conversion to mTORi can be followed by early appearance of de novo HLA-Abs, especially in patients with HLA-Abs preconversion, and this complication should be screened early after conversion.

The relationship between homocysteine and genes of folate-related enzymes in migraine patients.

BACKGROUND: It has been suggested that homocysteine (Hcy) and the 5'-10'-methylenetetrahydrofolate reductase (MTHFR) C677T variant are implicated in the pathogenesis of migraine. Homocysteine has the potential to damage endothelium and accelerate atherosclerosis. Genetic factors such as the MTHFR C677T polymorphism, and other polymorphisms in folate-related genes associated with high homocysteine levels, may contribute to increasing this vascular risk. RESULTS: We recruited 427 migraine patients (199 without aura [MO]; 228 with aura [MA]), and 310 controls in a neurologic clinic. Hcy levels and 6 polymorphisms corresponding to 6 folate-related genes, including the MTHFR C677T variant, were determined in all migraine participants and in a subset of 155 controls. We found higher sex-adjusted Hcy levels in MA (mean: 11.02 microM) than MO patients (9.86 microM; P = .005 for the difference). Hcy levels higher than 12.0 microM doubled the risk for MA (OR = 2.145; 95% confidence intervals [CI] = 1.3-3.4; P = .001), and those higher than 15.0 microM incurred a 6-fold increase (OR = 5.95; 95% CI = 2.1-20.0, P < .001). The number of MTHFR 677T alleles was the best genetic predictor of Hcy levels (r(2) = 0.06; P = 6.2e-6; corrected for genetic variants analyzed) and this effect remained significant after correction for other confounding factors. Using multi-dimensionality reduction approaches, we observed significant epigenetic interaction among some of the folate-related genetic variants to predict higher Hcy levels, and also among higher Hcy levels and folate-related genetic variants to predict the end-diagnosis of MA only among migraineurs. In controls, Hcy levels and the number of MTHFR 677T alleles were found to be intermediate between those observed in MA and MO patients. CONCLUSION: Our results suggest that MA patients have higher Hcy levels. We also observed complex epigenetic interaction among folate-related enzymes, sex, and Hcy levels predicting MA phenotype. Nevertheless, genetic factors explained only a minor proportion of the variance for both Hcy plasma levels and for predicting MA phenotype. Determination of MTHFR C677T polymorphisms and Hcy levels may be useful to identify patients with a high risk of suffering from MA.

Multilocus analyses reveal involvement of the ESR1, ESR2, and FSHR genes in migraine.

OBJECTIVE: Female hormone genes have been investigated in migraine in recent years. Research in this field has been controversial, especially in regard to ESR1 gene findings. None of the reports have yet to approach the problem from a multigenic point of view. METHODS: We investigated 5 polymorphisms implicated in female hormone metabolism (FSHR, CYP19A1, ESR1, NRIP1, and ESR2) in a cohort of 730 subjects matched for age and sex. The effect of gene-gene interaction was assessed using the set association approach, and the corresponding haplotypes were studied with PM Plus software. To corroborate initial results, we analyzed the selected markers using a cohort of 134 families in which 168 trios were suitable for transmission-disequilibrium test (TDT) analysis under the migraine with aura (MA) phenotype. RESULTS: A total of 356 consecutive migraine patients (198 with MA [76% females] and 158 migraine without aura [MO, 74% females], and 374 matched controls [71% females]) were genotyped. In the 2-point analyses, the ESR1 and ESR2 polymorphisms showed nominal association under MA/MO phenotype, and this association was higher with the FSHR polymorphism in MA females (P = .004, uncorrected). Using the SUMSTAT program, we observed ESR2-ESR1-FSHR significant gene-gene interaction, suggesting association with the MA/MO phenotype (P = .005; P = .003 in females), and with MA alone (P = .021; P = .030 for females).We corroborated that ESR2-ESR1-FSHR haplotypes interacted for migraine under a model-free hypothesis (empirical P = .010 for the whole sample; P = .001 for females), and the association was stronger for the MA phenotype alone (empirical P = 5.0e-4, under the heterogeneity model; P = .001 for females). These results were corroborated using family-based association approaches. We observed nominal association for ESR2 and ESR1 (P = .031 and .034, respectively) in the TDT study, and significant association for ESR1 using family-based association test statistics. Haplotype-TDT analyses showed further significant gene-gene interaction for ESR1-ESR2 (global P = .009), ESR2-FSHR (global P = .011), and nominally significant interaction for ESR2-ESR1-FSHR genes (global P = .037). CONCLUSION: We found significant association of female hormone metabolism polymorphisms under the perspective of multigene approach.

Lack of association of endothelial nitric oxide synthase polymorphisms and migraine.

OBJECTIVE: The aim of this study was to evaluate if 2 functional endothelial nitric oxide synthase (eNOS) gene polymorphisms might be risk factors for migraine. BACKGROUND: Nitric oxide synthase promotes the synthesis of nitric oxide (NO). NO is a potent vasodilator and mediates several processes involved in migraine pathophysiology. Only one study has suggested an association with migraine with aura. METHODS: We performed a sex- and age-matched case-control study using 2 eNOS polymorphisms (rs1800779 and rs1799983), which are in linkage disequilibrium. Genotypes were obtained with allele-specific probes in a real-time polymerase chain reaction assay. Genotypic and allelic distributions were compared with chi(2) method. We also estimated the reconstructed haplotypes and calculated ORs for individual haplotypes. RESULTS: A total of 337 migraine patients (188 with aura) and 341 healthy controls were recruited. We found no significant differences in the distribution of genotypes and alleles for either polymorphism among clinical subgroups. Neither rs1800779 nor rs1799983 polymorphisms increased the risk for suffering from migraine aura. CONCLUSIONS: As others have previously reported, we failed to demonstrate genetic association of the eNOS gene with migraine.

Double treatment with paricalcitol-associated calcifediol and cardiovascular risk biomarkers in haemodialysis.

BACKGROUND: The deficit of 25-hydroxyvitamin D (25OHD) associated with secondary hyperparathyroidism (SHPT) is a frequent finding in chronic kidney disease (CKD) patients on haemodialysis (HD). These events are associated with increased morbidity and mortality rates of cardiovascular (CV) origin. Adequate 25OHD serum levels as well as the use of selective vitamin D receptor activators (VDRA) have been shown to have beneficial and independent effects on bone mineral metabolism and cardiovascular risk. Currently, there is still controversy regarding the type of supplementation needed by CKD patients on HD. OBJECTIVE: The aim of our study was to evaluate whether there is a benefit of combination therapy with 25OHD, calcifediol and a VDRA, oral paricalcitol, on bone-mineral metabolism and inflammatory markers, compared to single treatment with each of these in a group of patients on HD. MATERIAL AND METHOD: We performed a prospective study of 6 months, involving 26 patients in our HD unit. We randomised patients into two groups: group 1 (G1) received oral paricalcitol treatment at doses of 1 mcg/day. Group 2 (G2) was treated with 1 ampoule calcifediol/wk (0.266 mg/wk=16 000U) orally. After 3 months of treatment, calcifediol and paricalcitol were added to the G1 and G2 respectively at the same doses, keeping these treatments together for 3 months to complete the 6 months of follow-up. Laboratory tests were performed at months 0, 3 and 6, measuring in all patients serum markers of 25OHD, calcium (Ca), phosphorus (P) and PTH. Bone turnover markers measured were: alkaline phosphatase (AP), aminoterminal propeptide of procollagen type 1 (Pinp1) and carboxyl-terminal telopeptide of type I collagen (CrossLaps), and inflammatory markers: IL-8. We also collected data on levels of insulin, glucose, haemoglobin, erythropoiesis-stimulating agents (ESAs) and rates of resistance to EPO and HOMA (homeostasis model assessment). RESULTS: We detected a deficit of 25-hydroxyvitamin D in all patients studied, with a mean of 13.67 ± 4.81 ng/ml. Supplementation with oral calcifediol significantly corrects this deficit without evidence of toxicity (35.36 ± 33.68 ng/ml in G1 at 6 months and 59.21 ± 26.50 ng/ml in G2 at 3 months). Paricalcitol treatment significantly reduces PTH levels in G1 at 3 months (P<.039). We also noted a decrease in bone marker Pinp1 with paricalcitol, pointing to a possible direct effect on bone cells (P<.001). Both treatment with paricalcitol and with calcifediol produced a significant decrease in levels of IL-8 (P<.001), a known inflammatory marker, drawing attention to a trend towards better response to erythropoiesis-stimulating agents (ESAs), possibly related to the decrease in inflammation. The HOMA index did not change significantly. CONCLUSION: Based on our results, we cannot conclude that the association of calcifediol and paricalcitol produces advantages over the effect of each drug separately. In addition, Paricalcitol by itself appears to have a direct effect on cellular bone remodelling.