Reliable biomarkers for decreased spatial navigation in the Young People with Obesity: Increased serum CRP and QUIN levels

Abstract Background: Obesity is increasing morbidity and mortality. Obesity and cognitive impairment research have focused on the negative consequences of obesity-related medical diseases on cognition. This study aimed to examine the effect of obesity on spatial navigation, and the relationship between changes in tryptophan kynurenine metabolites and spatial navigation in the people with obesity between 18 and 35 years of age. Methods: In 29 adults with obesity and 25 normal weight adults, we examined plasma levels of CRP, leptin, kynurenine (KYN), tryptophan (TRP), kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), and quinolinic acid (QUIN), as well as the TRP/KYN, KYNA/3-HK, and KYNA/QUIN ratios. Body and abdominal fat composition (AFC) were also examined. The EAT-26 was used to assess eating attitudes. We used Montreal cognitive assessment (MOCA), Reaction Time (RT), Rey-Osterrieth Complex Figure Test (RCFT), and Virtual-Reality-Based Route-Learning Test with subtests Route repetition task (RPT), Route retraction task (RRT), Directional-approach task (DAT) to measure cognitive abilities. Results: In participants with obesity, the EAT-26 score was higher (p= 0.006), but the MOCA total score (p=0.03) and RCFT copy subscale score (p=0.03), as well as the RPT (p< 0,001), RRT p= 0,004), and DAT (p< 0,001) percentage of correct answers, was lower than normal-weight participants. The QUIN was found to be a negative predictor of RRT (B=-7.29, CI: -12.98, -1.59, -0.31, p=0.01) and DAT (B=-6.15, CI: -9.83, -2.46, p=0.002), while AFC was a negative predictor of RPT (B=-1.01, CI: -1.47, -0.55, p< 0.001). CRP was likewise greater in participants with obesity and a negative predictor of RRT (B=-7.96, CI: -14.30, -1.62, p=0.02) and DAT (B=-9.25, CI: -16.34, -2.17, p=0.012). Discussion: The performance of participants with obesity without comorbidities was worse on visuospatial tests than healthy controls. QUIN and CRP may also help identify new serum biomarkers of poor visuospatial cognition in young adults with obesity