Contribution of Genetic Factors to Lower DHEAS in Patients with Rheumatoid Arthritis.

OBJECTIVE: Lower production of adrenal androgens has been confirmed in females with rheumatoid arthritis (RA); however, the mechanisms of this finding are not completely understood. The aim of our study was to assess the contribution of genetic factors associated with variability of dehydroepiandrosterone sulfate (DHEAS) levels to lower DHEAS in female RA patients. METHODS: 448 RA and 648 healthy controls were genotyped for single-nucleotide polymorphisms (SNPs) in genes ZKSCAN5 (rs11761528), SULT2A1 (rs2637125), HHEX (rs2497306), and ARPC1A (rs740160). Serum DHEAS concentrations were measured in 112 RA patients and 91 healthy women. RESULTS: The allele frequencies in DHEAS-related loci were similar in RA and controls. RA patients had significantly lower serum DHEAS concentrations compared to healthy women. The cumulative number of alleles associated with lower DHEAS within genes ZKSCAN5, SULT2A1, HHEX, and ARPC1A present in each individual negatively correlated with DHEAS levels in RA patients, but not in controls. Linear regression analysis showed significant effect of polymorphisms in genes ZKSCAN5 and ARPC1A on serum DHEAS levels in female RA patients but not in the control group. CONCLUSION: Our findings suggest that complex interactions exist between genotype and adrenal androgen hypofunction in RA.

A Combination of CD28 (rs1980422) and IRF5 (rs10488631) Polymorphisms Is Associated with Seropositivity in Rheumatoid Arthritis: A Case Control Study.

INTRODUCTION: The aim of the study was to analyse genetic architecture of RA by utilizing multiparametric statistical methods such as linear discriminant analysis (LDA) and redundancy analysis (RDA). METHODS: A total of 1393 volunteers, 499 patients with RA and 894 healthy controls were included in the study. The presence of shared epitope (SE) in HLA-DRB1 and 11 SNPs (PTPN22 C/T (rs2476601), STAT4 G/T (rs7574865), CTLA4 A/G (rs3087243), TRAF1/C5 A/G (rs3761847), IRF5 T/C (rs10488631), TNFAIP3 C/T (rs5029937), AFF3 A/T (rs11676922), PADI4 C/T (rs2240340), CD28 T/C (rs1980422), CSK G/A (rs34933034) and FCGR3A A/C (rs396991), rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA) and clinical status was analysed using the LDA and RDA. RESULTS: HLA-DRB1, PTPN22, STAT4, IRF5 and PADI4 significantly discriminated between RA patients and healthy controls in LDA. The correlation between RA diagnosis and the explanatory variables in the model was 0.328 (Trace = 0.107; F = 13.715; P = 0.0002). The risk variants of IRF5 and CD28 genes were found to be common determinants for seropositivity in RDA, while positivity of RF alone was associated with the CTLA4 risk variant in heterozygous form. The correlation between serologic status and genetic determinants on the 1st ordinal axis was 0.468, and 0.145 on the 2nd one (Trace = 0.179; F = 6.135; P = 0.001). The risk alleles in AFF3 gene together with the presence of ACPA were associated with higher clinical severity of RA. CONCLUSIONS: The association among multiple risk variants related to T cell receptor signalling with seropositivity may play an important role in distinct clinical phenotypes of RA. Our study demonstrates that multiparametric analyses represent a powerful tool for investigation of mutual relationships of potential risk factors in complex diseases such as RA.

Hyperinsulinemia in newly diagnosed patients with multiple sclerosis.

There are limited data regarding glucose metabolism dysregulation in multiple sclerosis (MS). Present study investigates glucose and insulin response during oral glucose tolerance test (oGTT) in MS patients. We examined 19 MS patients and 19 age, sex and body mass index (BMI) matched healthy controls. MS patients were newly diagnosed, untreated and with low Expanded Disability Status Scale (EDSS) score (1.1 ± 0.7). Plasma glucose, lactate, insulin and GLP-1 during oGTT, and fasting adipokines, lipid and inflammatory parameters were analyzed. Insulin sensitivity indices (ISI) were calculated. MS patients had comparable fasting (5.2 ± 0.3 vs. 5.0 ± 0.4 mmol/l, p = 0.05) and post-load glucose concentrations as controls. Insulin response to oral glucose load in MS was increased (p = 0.022). Insulin sensitivity was lower in MS compared to controls [ISI(Matsuda) 6.95 ± 3.44 vs. 10.60 ± 4.81, p = 0.011 and ISI(Cederholm) 49.9 ± 15.3 vs. 61.3 ± 16.3, p = 0.032]. We did not find any difference in lactate, GLP-1, total, HDL and LDL cholesterol, triglycerides, interleukin 6, tumor necrosis factor, C-reactive protein, resistin, leptin, adiponectin levels between groups. We found decreased insulin sensitivity with postprandial hyperinsulinemia in MS patients, which seems not to be related to chronic inflammation or physical inactivity. The role of hyperinsulinemia in CNS function impairment should be further investigated.