Genetic predisposition to higher production of interleukin-6 through -174 G > C polymorphism predicts global cognitive decline in oldest-old with cognitive impairment no dementia

• Published in: Arquivos de neuro-psiquiatria 2015-11, Vol.73 (11), p.899
• Main Authors: Fraga, Vanessa G, Guimarães, Henrique C, Teixeira, Antônio L, Barbosa, Maira T, Mateo, Elvis C C, Carvalho, Maria G, Caramelli, Paulo, Gomes, Karina B
• Format: Article
• Language: English
• Subjects: Age Factors; Aged; Cognition Disorders - genetics; Cognition Disorders - metabolism; Female; Genetic Association Studies; Genetic Predisposition to Disease; Genotyping Techniques; Humans; Interleukin-6 - biosynthesis; Interleukin-6 - blood; Interleukin-6 - genetics; Male; Neuropsychological Tests; Polymorphism, Single Nucleotide; Prospective Studies; Risk Factors; Severity of Illness Index
• ISSN: 1678-4227
• DOI: 10.1590/0004-282X20150137

Interleukin 6 (IL-6) is a pro-inflammatory cytokine upregulated in neurodegenerative contexts. The polymorphism IL-6 -174 G > C influences release levels of this cytokine. We aimed to evaluate the influence of IL-6 -174 G > C on global cognitive score of a group with cognitive impairment no dementia in one year of follow-up.Methods The subjects were categorized in two groups: short-term decline in global cognitive score and those with short-term stability or improvement. IL-6 174 G > C information were compared among these groups.Results We observed that individuals with cognitive impairment no dementia with GGlowergenotype were more frequent among global cognitive score non-decliners while carriers of at least one Chigherallele were more frequent in the group with global cognitive score decliners (p = 0.012; RR = 3.095 IC95%= 1.087-8.812).Conclusion These results suggest that the higher expression of IL-6 gene may be an independent risk factor for cognitive decline among individuals with cognitive impairment no dementia.