Effects of Gastric Bypass Surgery on the Brain: Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia.
Kristina E AlmbyMartin H LundqvistNiclas AbrahamssonSofia KvernbyMarkus FahlströmMaria J PereiraMalin GingnellF Anders KarlssonGiovanni FanniMagnus SundbomUrban WiklundSven HallerMark LubberinkJohan WikströmJan W ErikssonPublished in: Diabetes (2021)
While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by 18F-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.
Keyphrases
- glycemic control
- roux en y gastric bypass
- type diabetes
- positron emission tomography
- weight loss
- gastric bypass
- resting state
- white matter
- blood glucose
- pet ct
- computed tomography
- cerebral blood flow
- bariatric surgery
- obese patients
- pet imaging
- functional connectivity
- cardiovascular disease
- cerebral ischemia
- minimally invasive
- blood flow
- adipose tissue
- neural network
- body mass index
- coronary artery disease
- mass spectrometry
- skeletal muscle
- magnetic resonance
- weight gain
- magnetic resonance imaging
- physical activity
- deep brain stimulation
- subarachnoid hemorrhage
- single molecule
- molecular dynamics
- high fat diet induced
- atrial fibrillation
- drug induced
- early onset