Is Memory Decline Associated With Inflammatory Response?

C-reactive protein and cognitive impairment: A bidirectional Mendelian randomization study

OBJECTIVES

While C-reactive protein (CRP) has been solidly linked as a risk factor for cognitive impairment, observational research alone cannot definitively demonstrate a causal relationship. This study therefore sought to determine whether there was an association between CRP and the development of cognitive impairment.

METHODS

This study employed bidirectional Mendelian randomization (MR) to investigate the genetic association between CRP and cognitive impairment. genome-wide association studies (GWAS) summary statistics for both were sourced from IEU Open GWAS or prior reports. Cognitive GWAS's used were on tests designed to assess cognitive performance, fluid intelligence, prospective memory, and reaction time. The MR analysis applied several methods, including inverse variance-weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode approaches, then use of MR sensitivity analyses to interrogate findings.

RESULTS

Forward MR analysis showed that genetically proxied CRP was associated with prospective memory (P = 0.009), whereas there is little evidence to support an association between CRP and other cognitive tests. Reverse MR analysis indicated a potential association between genetic proxy cognitive performance (P = 0.002) and fluid intelligence score (P = 0.019) with CRP levels. For genetically proxied CRP on prospective memory, the level of pleiotropy (P > 0.05) and no genetic variant heterogeneity (P > 0.05) made bias unlikely, and leave-one-out tests also confirmed robust associations.

CONCLUSIONS

The effect of genetically proxied CRP on prospective memory, with little evidence on other cognitive tests. The reverse MR shows some evidence of genetically proxied cognition (cognitive performance and fluid intelligence) on CRP levels.

Inflammation and lipid metabolism as potential biomarkers of memory impairment across type 2 diabetes mellitus and severe mental disorders

INTRODUCTION

Neurocognitive impairment is a transdiagnostic feature across several psychiatric and cardiometabolic conditions. The relationship between inflammatory and lipid metabolism biomarkers and memory performance is not fully understood. This study aimed to identify peripheral biomarkers suitable to signal memory decline from a transdiagnostic and longitudinal perspective.

METHODS

Peripheral blood biomarkers of inflammation, oxidative stress and lipid metabolism were assessed twice over a 1-year period in 165 individuals, including 30 with schizophrenia (SZ), 42 with bipolar disorder (BD), 35 with major depressive disorder (MDD), 30 with type 2 diabetes mellitus (T2DM), and 28 healthy controls (HCs). Participants were stratified by memory performance quartiles, taking as a reference their global memory score (GMS) at baseline, into categories of high memory (H; n = 40), medium to high memory (MH; n = 43), medium to low memory (ML; n = 38) and low memory (L; n = 44). Exploratory and confirmatory factorial analysis, mixed one-way analysis of covariance and discriminatory analyses were performed.

RESULTS

L group was significantly associated with higher levels of tumor necrosis factor-alpha (TNF-α) and lower levels of apolipoprotein A1 (Apo-A1) compared to those from the MH and H groups (p < 0.05; η2p = 0.06-0.09), with small to moderate effect sizes. Moreover, the combination of interleukin-6 (IL-6), TNF-α, c-reactive protein (CRP), Apo-A1 and Apo-B compounded the transdiagnostic model that best discriminated between groups with different degrees of memory impairment (χ2 = 11.9-49.3, p < 0.05-0.0001).

CONCLUSIONS

Inflammation and lipid metabolism seem to be associated with memory across T2DM and severe mental illnesses (SMI). A panel of biomarkers may be a useful approach to identify individuals at greater risk of neurocognitive impairment. These findings may have a potential translational utility for early intervention and advance precision medicine in these disorders.

Clinical and Biological Correlates of Preoperative Cognitive Functioning of Glioma and Meningioma Patients

Objectives

This study aimed to investigate the association of high-sensitivity C-reactive protein (hsCRP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) serum concentrations with cognitive functions of glioma and meningioma patients.

Methods

177 brain tumor patients awaiting for brain tumor surgery participated in the study. Patients were assessed preoperatively, using neuropsychological tests for verbal memory, psychomotor speed, mental flexibility, and verbal fluency. The functional status of patients was evaluated using the Karnofsky Performance Index. Blood samples were drawn for evaluation of serum hsCRP and NT-proBNP concentrations upon hospital admission.

Results

The highest NT-proBNP concentration was observed in meningioma patients. Glioma and meningioma patients did not differ in hsCRB concentration. Patients in the highest hsCRP tertile were older and more frequently reported cardiovascular comorbidity. Patients in the highest NT-proBNP tertile were older, more frequently with cardiovascular comorbidity, females, and diagnosed with a meningioma. hsCRP was significantly related to slower psychomotor speed in high-grade glioma patients (rho = 0.30, p < 0.05). In meningioma sample, NT-proBNP correlated with decreased psychomotor speed (rho = 0.38, p < 0.01), mental flexibility (rho = 0.33, p < 0.01), worse cumulative learning (rho = −0.27, p < 0.05), and delayed recall (rho = 0.30, p < 0.01). However, the relationship between the NT-proBNP and cognitive functions became nonsignificant when demographic and clinical covariates were included into analysis. Higher hsCRP concentration remained significantly related to slower psychomotor speed (p = 0.02) and worse mental flexibility (p = 0.05) in glioma patients, independently from demographic and clinical covariates. Preoperative cognitive functioning was also predicted by older age, gender, side and location of the tumor, and tumor malignancy, and general functional status of a patient.

Conclusions

NT-proBNP was not associated with memory, language, and attention/executive cognitive domains of glioma and meningioma patients. Increased hsCRP was related to slower psychomotor speed and worse mental flexibility in glioma patients, indicating that inflammation processes are important for cognitive functioning in glial tumors.