Cognition and brain oxygen metabolism improves after bariatric surgery-induced weight loss: A pilot study.

Objective: The primary objectives of this pilot study were to assess cognition and cerebral metabolic rate of oxygen (CMRO ₂ ) consumption in people with severe obesity before (baseline), and again, 2- and 14-weeks after sleeve gastrectomy bariatric surgery.
Methods: Six people with severe/class 3 obesity (52 ± 10 years, five females, body mass index (BMI) = 41.9 ± 3.9 kg/m ² ), and 10 normal weight sex- and age-matched healthy controls (HC) (48 ± 6 years, eight females, 22.8 ± 1.9 kg/m ² ). Global CMRO ₂ was measured non-invasively using MRI and cognition using the Integneuro testing battery.
Results: Following a sleeve gastrectomy induced weight loss of 6.4 ± 2.5 kg (% total-body-weight-lost = 5.4) over two-weeks, cognition total scores improved by 0.8 ± 0.5 T-scores (p=0.03, 15.8% improvement from baseline). Weight loss over 14-weeks post-surgery was 15.4 ± 3.6 kg (% total-body-weight-lost = 13.0%) and cognition improved by 1.1 ± 0.4 (p=0.003, 20.6% improvement from baseline). At 14-weeks, cognition was 6.4 ± 0.7, comparable to 6.0 ± 0.6 observed in the HC group. Baseline CMRO ₂ was significantly higher compared to the HC (230.4 ± 32.9 vs. 177.9 ± 33.9 µmol O ₂ /100 g/min, p=0.02). Compared to baseline, CMRO ₂ was 234.3 ± 16.2 µmol O ₂ /100 g/min at 2-weeks after surgery (p=0.8, 1.7% higher) and 217.3 ± 50.4 at 14-weeks (p=0.5, 5.7% lower) after surgery. 14-weeks following surgery, CMRO ₂ was similar to HC (p=0.17).
Conclusion: Sleeve gastrectomy induced weight loss was associated with an increase in cognition and a decrease in CMRO ₂ observed 14-weeks after surgery. The association between weight loss, improved cognition and CMRO ₂ decrease should be evaluated in larger future studies.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2022 Anwar, Tucker, Puzziferri, Samuel, Zaha, Lingvay, Almandoz, Wang, Gonzales, Brothers, Nelson and Thomas.)