Cytokines are small proteins secreted by cells that serve as molecular messengers between cells. Pro-inflammatory cytokines - which function in the immune system - may be involved in alcohol dependence (AD). A study of three polymorphisms of the interleukin-1 gene complex (IL-1) and one of the tumor necrosis factor-alpha (TNFα) has found that IL-1 may directly contribute to AD among Spanish Caucasian males.
Results will be published in the December issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"Cytokines are proteins which mediate and regulate the inflammatory reaction in infectious and autoimmune diseases," explained Pilar A. S-iz, associate professor of psychiatry at the University of Oviedo, Spain and corresponding author for the study. "Clinical observation of increased circulating levels of pro-inflammatory cytokines such as IL-1 and TNFα in patients with alcohol liver disease suggests that they might play a role on the pathogenesis of the disease. Additionally, these cytokines act in the central nervous system affecting the functionality of the serotoninergic and dopaminergic systems, which have been also related to the pathophysiology of AD, and with the brain reward systems involved in alcohol reinforcement."
S-iz and her colleagues recruited 200 (169 males, 31 females) AD patients from an outpatient detoxification unit, as well as 420 (216 males, 204 females) healthy individuals without a history of drug/alcohol/psychiatric problems (known as "controls"), from the north of Spain. All of the Spanish Caucasian participants were genotyped for four polymorphisms -IL-1α -889 C/T, IL-1- +3953 C/T, IL-1RA (86bp)n, and TNFα -308A/G - and assessed at baseline and again at six months for alcohol intake, addiction severity, and biomarkers of alcohol intake.