Inflammatory biomarkers and cognitive functioning in individuals with euthymic bipolar disorder: exploratory study

Abstract

Background Neurobiological research frequently implicates inflammatory and neurogenic components with core aspects of bipolar disorder. Even in periods of symptom remission (euthymia), individuals with bipolar disorder experience cognitive impairments, which are increasingly being proposed as an outcome for interventions; identifying biomarkers associated with cognitive impairment in people with bipolar disorder could advance progress in this therapeutic field through identifying biological treatment targets. Aims We aimed to identify proteomic biomarker correlates of cognitive impairment in individuals with euthymic bipolar disorder. Method Forty-four adults with a bipolar disorder diagnosis in euthymia underwent a battery of cognitive assessments and provided blood for biomarkers. We examined a comprehensive panel of inflammatory and trophic proteins as putative cross-sectional predictors of cognition, conceptualised according to recommended definitions of clinically significant cognitive impairment (binary construct) and global cognitive performance (continuous measure). Results A total of 48% of the sample met the criteria for cognitive impairment. Adjusting for potentially important covariates, regression analyses identified lower levels of three proteins as significantly and independently associated with cognitive deficits, according to both binary and continuous definitions (interleukin-7, vascular endothelial growth factor C and placental growth factor), and one positively correlated with (continuous) global cognitive performance (basic fibroblast growth factor). Conclusions This study identifies four candidate markers of cognitive impairment in bipolar disorder, none of which have been previously compared with cognitive function in participants with bipolar disorder. Pending replication in larger samples and support from longitudinal studies, these markers could have implications for treating cognitive dysfunction in this patient population.

Cognitive impairment in long-COVID and its association with persistent dysregulation in inflammatory markers

“…For example, in adults with multiple sclerosis, a higher serum concentration of the anti-inflammatory marker IL-1RA was associated with better social-cognitive functioning ( 43 ). A study of 42 adults with bipolar disorder found that IL-7 levels were significantly associated with measures of cognition, showing higher levels in the cognitively unimpaired group and a positive correlation with cognitive performance ( 44 ). Further, preclinical studies indicate that treatment with G-CSF, a growth factor involved in neuroprotection and plasticity, may contribute to improved cognitive function in a model of traumatic brain injury ( 45 ).…”

A systematic review of the biomarkers associated with cognition and mood state in bipolar disorder

“…Therefore, the acute clinical state could modify the pattern or magnitude of neurocognitive impairment in patients with BD, but it is still under discussion (Kurtz and Gerraty, 2009). Furthermore, our understanding of the physiological or biological mechanisms underlying cognitive impairment in BD remains limited (Strawbridge et al 2021). It is of great importance to understand and delve into the mechanisms underlying cognitive impairment for a better understanding of the role that cognition plays in pathology and to design more effective treatment approaches.…”