Cytokines and memory across the mature life span of women

Increasing evidence suggests a role of the immune system in modulation of cognition, but details on affected memory systems are largely lacking. We therefore aimed to study the relation between selected cytokines and subsets of memory, and the impact of age in these relations. From a random population-based sample (the Betula Prospective Cohort Study), 298 women (age 45-90) were studied in terms of episodic recall and recognition, semantic fluency and knowledge, and prospective memory. Circulating cytokines of relevance for cognition and aging were measured with ELISA. Levels of interleukin (IL)-6 and sIL-2R were significantly and negatively associated with most cognitive variables, while the opposite was true for IL-1β. Age shared substantial variance with both cytokines and memory, and turned most correlations non-significant when controlled for together with education, BMI and presence of disease. Interactions between age and cytokines were further analyzed in multiple regressions. For IL-6, significant negative interactions with age were found for semantic fluency (p<0.05) and prospective memory (p<0.01), and for sIL-2R in predicting semantic knowledge (p<0.05), indicating an increased negative impact of these cytokines on memory with increasing age. In conclusion, the study indicates a relation between cytokines and memory that appears to be largely mediated by age, and supports the suggestion that cytokine dysregulation with higher age may interact with cognitive aging.     

Lipopolysaccharide-induced experimental immune activation does not impair memory functions in humans

Reconsolidation studies have led to the hypothesis that memory, when labile, would be modified in order to incorporate new information. This view has reinstated original propositions suggesting that short-term memory provides the organism with an opportunity to evaluate and rearrange information before storing it, since it is concurrent with the labile state of consolidation. The Chasmagnathus associative memory model is used here to test whether during consolidation it is possible to change some attribute of recently acquired memories. In addition, it is tested whether these changes in behavioral memory features can be explained as modifications on the consolidating memory trace or as a consequence of a new memory trace. We show that short-term memory is, unlike long-term memory, not context specific. During this short period after learning, behavioral memory can be updated in order to incorporate new contextual information. We found that, during this period, the cycloheximide retrograde amnesic effect can be reverted by a single trial in a new context. Finally, by means of memory sensitivity to cycloheximide during consolidation and reconsolidation, we show that the learning of a new context (CS) during this short-term memory period builds up a new memory trace that sustains the behavioral memory update.     

Cortisol,interleukins and S100B in delirium in the elderly

In independent studies delirium was associated with higher levels of cortisol, interleukin(IL)s, and S100B. The aim of this study was to simultaneously compare cortisol, IL-6, IL-8, and S100B levels in patients aged 65 years and older admitted for hip fracture surgery with and without delirium. Cortisol, IL-6, IL-8, and S100B were assayed in repeated blood samples. 120 patients (mean age 84 years, 62 patients with delirium) were included. Highest levels of IL-8 (27.1, 95% Confidence Interval (CI): 13.6–53.1 pg/ml) and cortisol (666, 95% CI: 475–859 nmol/L) were before delirium, but of IL-6 (84.3, 95% CI: 46.5–151.4 pg/mL) and S100B (0.18, 95% CI: 0.12–0.24 μg/L) during delirium. In multivariable analysis cortisol, LogIL-6, and LogS100B were significantly associated with delirium, but adjusted for pre-existing cognitive impairment, only LogS100B remained significantly associated. Cortisol, IL-6 and S100B may have a role in the pathogenesis of delirium, but S100B is the strongest independent marker.     

Cumulative trauma,emotion reactivity and salivary cytokine levels following acute stress in healthy women

Background and Objectives: To better understand how trauma leads to poor health, this study examined whether cumulative trauma and emotion reactivity contribute to pro- (IL-1β) and anti-inflammatory (IL-10) salivary cytokine levels after stress.

Design: Seventy-three women, screened to be physically and mentally healthy, completed an acute stress paradigm and measures of lifetime trauma exposure.

Method: Saliva was collected 10?min before (i.e., baseline) and 35?min after the onset of a 10-min stressor. State negative and positive emotion were measured at baseline and post-stress.

Results: Most participants reported exposure to at least one trauma, with a mean of five. Cumulative trauma was associated with higher post-stress IL-1β and IL-1β/IL-10, but not with IL-10 or changes in emotion. Declines in positive emotion correlated with greater post-stress IL-1β.

Conclusions: These findings suggest that both cumulative trauma exposure and positive emotion have implications for salivary cytokine responses to acute stress. The inclusion of healthy women strengthens internal validity, and increases confidence that observed associations between trauma and salivary cytokine responses can be attributed to trauma, rather than to confounding health problems. This study adds to the growing literature examining how trauma may connect to cytokines, and ultimately, poor health.