1694-P: Impact of Bariatric Surgery on Increased Circulating Levels of Several Biomarkers for Neurodegenerative Diseases in Obese Chinese Free

Background: Increasing studies have shown a strong association of obesity with neurodegenerative disorders. However, there is scarce evidence for the direct link between obesity and neurodegeneration. In addition, although bariatric surgery is well-known to be an effective therapy for obesity-related metabolic dysfunctions, its impact on cognitive function remains uncertain. This study aims to address these questions by monitoring several well-established circulating biomarkers for neurodegeneration in morbidly obese subjects receiving bariatric surgery.

Methods: The single molecule array, an ultra-sensitive enzyme-linked immunosorbent assay technique, was used for measurement of plasma levels of p-tau 181, tau, Aβ42 and Aβ40 in 36 morbidly obese individuals (BMI=39.46±7.87) before and after bariatric surgery for 12 months and 55 lean subjects (BMI=21.79±2.84).

Results: Plasma levels of p-tau 181, tau, Aβ42 and Aβ40 in obese individuals, were significantly elevated compared to lean individuals, and positively correlated with several indices of obesity, including body weight, BMI and waist circumference. In obese subjects who received bariatric surgery, significant improvements on many metabolic parameters were observed, such as BMI, HOMA-IR and triglyceride. However, circulating p-tau 181 levels in obese individuals kept unchanged before and after treatment, while tau, Aβ42 and Aβ40 levels increased from 4.34±0.74 to 6.06±0.38 pg/ml, 4.37±0.51 to 8.47±0.41 pg/ml, and 98.89±11.53 to 174.14±8.99 pg/ml, respectively.

Conclusions: Circulating levels of several neurodegenerative biomarkers are elevated in obesity but such changes cannot be reversed by bariatric surgery. These findings implicate the adverse effects of obesity at the early stage of life on neurodegeneration may be last-lasting and hardly repairable, highlighting the importance of maintaining a healthy weight in prevention of neurodegenerative diseases.