Abstract TMP28: Serotonin Transporter Polymorphism Impact on Cortisol Level and Outcome After Stroke

Abstract

Background: The short (s) allele of a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) is related to reduced serotonin transporter efficiency and an increased vulnerability to stress and mental disorders. The 5-HTTLPR s allele was reported as associate with hypothalamic-pituitary-adrenal (HPA)-axis reactivity to stress, depression and negatively impact on memory. Acute stroke is associated with elevated cortisol levels as part of the body’s reaction to a stress provoking event. We investigated whether 5-HTT genotype interacts with physiological stress to impact on outcome after stroke. Methods: Data from 485 non-depressed cognitively intact first-ever mild to moderate stroke patients from the TABASCO study were available. Patients underwent 3T MRI scans, saliva cortisol measure and comprehensive neuropsychological assessments at admission, 6, and 12 and 24 months thereafter. Results: Carriers of the 5-HTT-s allele (23.2%) had significantly higher admission bedtime salivary cortisol (p=0.042) and more depressive symptoms 12 and 24 months after the index event (p=0.043, p=0.05, respectively) than non-carriers. Higher admission salivary cortisol levels negatively correlated with hippocampal and amigdalar volume at admission (r=-0.257, p=0.004; r=-0.177, p=0.048, respectively) as well as with lower cognitive and higher depression scores 24 months post-stroke (r=-0.2, p=0.032, r=0.245, p=0.007, respectively). The association between salivary cortisol levels, depressive and cognitive scores was stronger in 5-HTT-s carriers than non-carriers. Conclusions: We report that carriers of the 5-HTT-s allele may be at risk to develop depressive symptoms post-stroke. The interactive effects of the s allele and cortisol levels on hippocampal volume and post-stroke depressive symptoms, as well as cognitive performance, suggest that the negative effect of the serotonin polymorphism on the development of post-stroke depression and cognitive decline is mediated by the HPA axis. Since genetic factors may influence vulnerability to the adverse effects of stress, serotonin receptors may provide a novel target for therapeutics to prevent depression and cognitive deterioration in stroke patients.