<b>Beta cell mass in individuals with and without post-bariatric hypoglycemia after Roux-en-Y Gastric Bypass</b>

<p dir="ltr">Post-bariatric hypoglycemia (PBH) is a serious complication of Roux-en-Y gastric bypass (RYGB), characterized by severe hypoglycemia that may lead to loss of consciousness and seizures. The exact mechanism of PBH is poorly understood. One potential mechanism is beta cell expansion. To this end, we investigated beta cell mass in individuals with and without PBH after RYGB using [<sup>68</sup>Ga]Ga-NODAGA-exendin-4 PET/CT imaging. Individuals with PBH (n=10) and without PBH (n=9) after RYGB were included. PET/CT imaging was performed after infusion with 102.2±6.9 MBq of the [<sup>68</sup>Ga]Ga-NODAGA-exendin-4 tracer to quantify pancreatic beta cell mass. The two groups did not differ with respect to sex, age, BMI and total body weight loss after RYGB. Time between RYGB and inclusion was longer for individuals with PBH compared to those without. Beta cell mass did not differ between the groups. Individuals with PBH had a smaller pancreas than those without. Beta cell mass correlated neither with body weight parameters nor with metabolic parameters.<b> </b>Our data indicating that beta cell mass does not differ between individuals with and without PBH after RYGB argue against expansion of beta cell mass to explain PBH.</p>