Higher frequency of septic shock in septic patients with the 47C allele (rs4880) of the SOD2 gene.

AIM: To analyze the effect of the two different versions of the manganese superoxide dismutase gene (SOD2) on sepsis. The SOD2 gene presents the 47C>T single nucleotide polymorphism (SNP; ID: rs4880) which produces MnSOD with different activities. The -9Val MnSOD (47T allele) is less efficient than the -9Ala version (47C allele). During sepsis there are abundance of ROS, high SOD2 expression and excess of H(2)O(2) synthesis. High concentrations of H(2)O(2) could affect the sepsis scenario and/or the sepsis outcome. METHODS: We determined the 47C>T single nucleotide polymorphism (SNP) frequencies in 529 critically ill patients with or without sepsis, facing outcome. To collect information on population frequencies, we obtained a pilot 47C>T genotypic and allelic frequencies in a random group of 139 healthy subjects. RESULTS: We compared the 47C allele carriers (47CC+47CT genotypes) with 47TT homozygotes and noticed a significant association between 47C allele carriers and septic shock in septic patients (P=0.025). With an adjusted binary multivariate logistic regression, incorporating 47C>T SNP and the main clinical predictors, we showed high SOFA scores [P<0.001, OR=9.107 (95% CI=5.319-15.592)] and 47C allele [P=0.011, OR=2.125 (95% CI=1.190-3.794)] were significantly associated with septic shock outcome. With this information we presented a hypothesis suggesting that this negative outcome from sepsis is possibly explained by effects on cellular stress caused by 47C allele. CONCLUSION: In our population there was a significant higher frequency of septic shock in septic patients with the 47C allele of the SOD2 gene. This higher 47C allele frequency in septic patients with negative outcome could be explained by effects of higher activity MnSOD on cellular stress during the sepsis.

Very low frequencies of Toll-like receptor 2 supposed-2029T and 2258A (RS5743708) mutant alleles in southern Brazilian critically ill patients: would it be a lack of worldwide-accepted clinical applications of Toll-like receptor 2 variants?

Toll-like receptor 2 (TLR2) is a recognition receptor for the widest repertoire of pathogen-associated molecular patterns. Two polymorphisms of TLR2 could be linked to reduced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) activation and to increased risk of infection (supposed-2029C>T and 2258G>A). We investigated the supposed-2029C>T and 2258G>A TLR2 polymorphisms in 422 critically ill patients of European origin from southern Brazil (295 with sepsis and 127 without sepsis) and reviewed 33 studies on these polymorphisms, conducting a quality assessment with a score system. Among our patients we found only one heterozygote (1/422) for the supposed-2029C>T and none for the 2258G>A (0/422) single nucleotide polymorphism (SNP). We were unable to find a clinical application of supposed-2029T and 2258A allele analyses in our southern Brazilian population. Our review detected that current TLR2 SNP assays had very controversial and contradictory results derived from reports with a variety of investigation quality criteria. We suggest that, if analyzed alone, the supposed-2029C>T and 2258G>A TLR2 SNP are not good candidates for genetic markers in studies that search for direct or indirect clinical applications between genotype and phenotype. Future efforts to improve the knowledge and to provide other simultaneous genetic markers might reveal a more effective TLR2 effect on the susceptibility to infectious diseases.

LEI0258 microsatellite variability and its relationship to B-F haplotypes in Brazilian (blue-egg Caipira) chickens

A total of 149 chickens from two different sources (one non-commercial, the other commercial) was tested for variability of the LEI0258 microsatellite. Fifty- three genotypes, explainable by 15 alleles, were found. There are clear allele and heterozygosity differences between the two samples. One of them was simultaneously studied for the MHC B-F haplotypes. Strong genetic disequilibrium was observed between the variants of the two systems, therefore providing a cheap alternative for MHC genotyping.