Pancreatic α-cell mass in obesity

While it is well recognized that obesity is associated with an increased beta-cell mass, the association with alpha-cell mass is less clear. Type 2 diabetes (T2DM) associated with obesity is a bihormonal disease characterized by inadequate insulin secretion and hyperglucagonaemia. We examined beta- and alpha-cell mass throughout the pancreas in obese and lean subjects. Pancreatic tissue of the head, body and tail region of the pancreas was examined from 15 obese subjects (body mass index [BMI] >= 27 kg/m(2)) and 15 age-matched lean subjects (BMI <= 25 kg/m(2)) without diabetes. In obese subjects both beta- and alpha-cell mass were proportionally higher compared with lean subjects, thereby maintaining the beta- to alpha-cell ratio. The adaptation to obesity occurred preferentially in the head of the pancreas. As data so far have been derived from histological studies of beta- and alpha-cell adaptation, in which the head region of the human pancreas was not included, the adaptive capacity of humans to obesity has previously been underestimated. Obesity is associated with an increased alpha-cell mass, which could contribute to the hyperglucagonaemia observed in people with T2DM.