NR3C1 polymorphisms in Brazilians of Caucasian, African, and Asian ancestry: glucocorticoid sensitivity and genotype association.

OBJECTIVE: The Brazilian population has heterogeneous ethnicity. No previous study evaluated NR3C1 polymorphisms in a Brazilian healthy population. MATERIALS AND METHODS: We assessed NR3C1 polymorphisms in Brazilians of Caucasian, African and Asian ancestry (n = 380). In a subgroup (n = 40), we compared the genotypes to glucocorticoid (GC) sensitivity, which was previously evaluated by plasma (PF) and salivary (SF) cortisol after dexamethasone (DEX) suppression tests, GC receptor binding affinity (K d ), and DEX-50% inhibition (IC 50 ) of concanavalin-A-stimulated mononuclear cell proliferation. p.N363S (rs6195), p.ER22/23EK (rs6189-6190), and BclI (rs41423247) allelic discrimination was performed by Real-Time PCR (Polymerase Chain Reaction). Exons 3 to 9 and exon/intron boundaries were amplified by PCR and sequenced. RESULTS: Genotypic frequencies (%) were: rs6195 (n = 380; AA:96.6/AG:3.14/GG:0.26), rs6189-6190 (n = 264; GG:99.6/GA:0.4), rs41423247 (n = 264; CC:57.9/CG:34.1/GG:8.0), rs6188 (n = 155; GG:69.6/GT:25.7/TT:4.7), rs258751 (n = 150; CC:88.0/CT:10.7/TT:1.3), rs6196 (n = 176; TT:77.2/TC:20.4/CC:2.4), rs67300719 (n = 137; CC:99.3/CT:0.7), and rs72542757 (n = 137; CC:99.3/CG:0.7). The rs67300719 and rs72542757 were found only in Asian descendants, in whom p.N363S and p.ER22/23EK were absent. The p.ER22/23EK was observed exclusively in Caucasian descendants. Hardy-Weinberg equilibrium was observed, except in the Asian for rs6188 and rs258751, and in the African for p.N363S. The K d , IC 50 , baseline and after DEX PF or SF did not differ between genotype groups. However, the mean DEX dose that suppressed PF or SF differed among the BclI genotypes (P = 0.03). DEX dose was higher in GG- (0.7 ± 0.2 mg) compared to GC- (0.47 ± 0.2 mg) and CC-carriers (0.47 ± 0.1 mg). CONCLUSION: The genotypic frequencies of NR3C1 polymorphisms in Brazilians are similar to worldwide populations. Additionally, the BclI polymorphism was associated with altered pituitary-adrenal axis GC sensitivity.

NR3C1 polymorphisms in Brazilians of Caucasian, African, and Asian ancestry: glucocorticoid sensitivity and genotype association / Polimorfismos NR3C1 em brasileiros de ascendência caucasiana, africana e asiática: sensibilidade aos glicocorticoides e associação de genótipos

Objective : The Brazilian population has heterogeneous ethnicity. No previous study evaluated NR3C1 polymorphisms in a Brazilian healthy population. Materials and methods : We assessed NR3C1 polymorphisms in Brazilians of Caucasian, African and Asian ancestry (n = 380). In a subgroup (n = 40), we compared the genotypes to glucocorticoid (GC) sensitivity, which was previously evaluated by plasma (PF) and salivary (SF) cortisol after dexamethasone (DEX) suppression tests, GC receptor binding affinity (K d ), and DEX-50% inhibition (IC 50 ) of concanavalin-A-stimulated mononuclear cell proliferation. p.N363S (rs6195), p.ER22/23EK (rs6189-6190), and BclI (rs41423247) allelic discrimination was performed by Real-Time PCR (Polymerase Chain Reaction). Exons 3 to 9 and exon/intron boundaries were amplified by PCR and sequenced. Results : Genotypic frequencies (%) were: rs6195 (n = 380; AA:96.6/AG:3.14/GG:0.26), rs6189-6190 (n = 264; GG:99.6/GA:0.4), rs41423247 (n = 264; CC:57.9/CG:34.1/GG:8.0), rs6188 (n = 155; GG:69.6/GT:25.7/TT:4.7), rs258751 (n = 150; CC:88.0/CT:10.7/TT:1.3), rs6196 (n = 176; TT:77.2/TC:20.4/CC:2.4), rs67300719 (n = 137; CC:99.3/CT:0.7), and rs72542757 (n = 137; CC:99.3/CG:0.7). The rs67300719 and rs72542757 were found only in Asian descendants, in whom p.N363S and p.ER22/23EK were absent. The p.ER22/23EK was observed exclusively in Caucasian descendants. Hardy-Weinberg equilibrium was observed, except in the Asian for rs6188 and rs258751, and in the African for p.N363S. The K d , IC 50 , baseline and after DEX PF or SF did not differ between genotype groups. However, the mean DEX dose that suppressed PF or SF differed among the BclI genotypes (P = 0.03). DEX dose was higher in GG- (0.7 ± 0.2 mg) compared to GC- (0.47 ± 0.2 mg) and CC-carriers (0.47 ± 0.1 mg). Conclusion : The genotypic frequencies of NR3C1 polymorphisms in Brazilians are similar to worldwide populations. Additionally, the BclI polymorphism ...

Objetivo : Este estudo avalia polimorfismos (SNPs) do NR3C1 na população brasileira, que possui origem étnica heterogênea. Materiais e métodos : SNPs do NR3C1 foram avaliados em brasileiros de ancestralidade caucasiana, africana ou japonesa (n = 380). Em um subgrupo (n = 40), os genótipos foram comparados à sensibilidade aos glicocorticoides (GC), previamente avaliada por cortisol plasmático (PF) e salivar (SF) após supressão com dexametasona (DEX), ensaio de afinidade do receptor ao GC (K d ) e inibição por DEX de 50% da proliferação de mononucleares estimulada por concanavalina-A (IC 50 ). Discriminação alélica de p.N363S (rs6195), p.ER22/23EK (rs6189-6190) e BclI (rs41423247) foi realizada por PCR em tempo real. Éxons 3 a 9 e transições éxon/íntron foram amplificados e sequenciados. Resultados : Frequências genotípicas (%) foram: rs6195 (n = 380; AA:96,6/AG:3,14/GG:0,26), rs6189-6190 (n = 264; GG:99,6/GA:0,4), rs41423247 (n = 264; CC:57,9/CG:34,1/GG:8,0), rs6188 (n = 155; GG:69,6/GT:25,7/TT:4,7), rs258751 (n = 150; CC:88,0/CT:10,7/TT:1,3), rs6196 (n = 176; TT:77,2/TC:20,4/CC:2,4), rs67300719 (n = 137; CC:99,3/CT:0,7), e rs72542757 (n = 137; CC:99,3/CG:0,7). Enquanto rs67300719 e rs72542757 foram exclusivos dos nipodescendentes, p.N363S e p.ER22/23EK estavam ausentes nesses indivíduos. p.ER22/23EK foi exclusivo dos descendentes de caucasianos. Equilíbrio de Hardy-Weinberg foi observado, exceto nos nipodescendentes para rs6188 e rs258751 e nos afrodescendentes para p.N363S. K d , IC 50 , PF ou SF basal ou após DEX foram semelhantes entre os genótipos. Entretanto, a dose média de DEX que suprimiu PF ou SF diferiu entre os genótipos BclI (P = 0,03), sendo maior nos carreadores GG (0,7 ± 0,2 mg) comparada aos GC (0,47 ± 0,2 mg) e CC (0,47 ± 0,1 mg). Conclusão : As ...

Glucocorticoid resistance in dialysis patients may impair the kidney allograft outcome.

This study examines in vitro steroid sensitivity in chronic renal failure (CRF) patients and its influence on the allograft outcome. We determined the inhibitory effect of dexamethasone (DEX) on concanavalin A (Con-A)-stimulated peripheral blood mononuclear cell (PBMC) proliferation, and glucocorticoid receptor' (GR) number of binding sites (B(max)) and affinity (K(d)) in 28 CRF patients and 40 normal healthy controls. Based on K(d) values >95th percentile from controls, patients were divided into two groups: glucocorticoid resistant (n = 11) and glucocorticoid sensitive (n = 17). Patients were followed during 18 months post-transplantation observing acute rejection episodes (ARE), chronic allograft nephropathy (CAN), allograft failure and death. The DEX concentration that caused 50% inhibition of Con-A-stimulated PBMC proliferation (IC(50)) was higher in CRF than in healthy controls (2.2 x 10(-5) +/- 1.0 x 10(-5) versus 8.3 x 10(-6) +/- 4.2 x 10(-6) mol/L, P = 0.02). Values of K(d) (12.4 +/- 1.8 versus 7.2 +/- 0.9 nM) and B(max) (7.7 +/- 1.1 versus 4.1 +/- 0.3 fmol/mg protein) were higher in CRF patients (P = 0.02 and P = 0.001, respectively). There were higher incidences of ARE (P = 0.02) and CAN (P = 0.002) in the glucocorticoid-resistant group. Univariate and multivariate logistic regression showed that K(d) was an independent predictor of ARE (OR 8.8, P = 0.03) as well as of CAN (OR 16.5, P = 0.01). In conclusion, we observed glucocorticoid resistance in a subgroup of CRF patients undergoing dialysis, which led to a higher morbidity due to ARE and CAN in an 18-month follow-up period.

Androgenic-anabolic steroids associated with mechanical loading inhibit matrix metallopeptidase activity and affect the remodeling of the achilles tendon in rats.

BACKGROUND: The indiscriminate use of anabolic-androgenic steroids has been shown to induce pathologic changes in the Achilles tendon in several situations. PURPOSE: To study tendon remodeling in rats treated with anabolic-androgenic steroids combined with an exercise program. STUDY DESIGN: Controlled laboratory study. METHODS: Wistar rats were grouped as follows: sedentary (group I), injected with anabolic-androgenic steroids only (group II), trained only (group III), and trained and injected with anabolic-androgenic steroids (group IV). The trained groups performed jumps in water: 4 series of 10 jumps each, with an overload of 50% to 70% of the animal's body weight and a 30-second rest interval between series, for 6 weeks. Anabolic-androgenic steroids (5 mg/kg) were injected subcutaneously. Activity of matrix metallopeptidases, a marker for tendon remodeling, was analyzed in tissue extracts by zymography on gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. RESULTS: Morphological analyses of tendons showed that in group II, the most external layer that covers the tendon was thicker with aggregation of the collagen fibers, suggesting an increase in collagen synthesis. In group IV, an inflammatory infiltrate and fibrosis in tendons as well as a pronounced increase of the serum corticosterone level were observed. This training protocol upregulated matrix metallopeptidase activity, whereas anabolic-androgenic steroid treatment strongly inhibited this activity. The appearance of lytic bands with molecular masses of approximately 62 and 58 kDa suggests the activation of matrix metallopeptidase-2. CONCLUSION: Anabolic-androgenic steroid treatment can impair tissue remodeling in the tendons of animals undergoing physical exercise by down-regulating matrix metallopeptidase activity, thus increasing the potential for tendon injury. CLINICAL RELEVANCE: Since the AAS abuse is so widespread, a better comprehension of the pathological effects induced by these drugs may be helpful for the development of new forms of therapy of AAS-induced lesions.