Endocrine Abstracts

Aims: Exercise increases beta cell health in people at risk of, and with established type 2 diabetes (T2D). These benefits of exercise have not been characterised in T1D. Over 10% of beta cells are still present at the time of diagnosis with T1D, and exercise has the potential to preserve them. We aimed to explore the mechanisms through which exercise could improve beta cell health in T1D by investigating the effects of exercise serum on apoptosis and proliferation of the MIN6 mouse insulinoma cell line.

Methods: Fasted blood was taken from 10 healthy male subjects before and after 40 min of varied unsupervised moderate intensity exercise, and from 11 well-trained male subjects before and after a 9 day intensive cycling exercise training study. Apoptosis was measured in MIN6 (24 h+100 μM H₂O₂) by flow cytometry (AnnexinV-FITC, 7-AAD staining). Proliferation of MIN6 was measured using PromegaCellTiter96aqueousOneCell proliferation assay daily over four days. Experimental cultures were supplemented with 10% of either pre- or post-exercise serum.

Results: MIN6 incubated in post-exercise serum showed 6.2%(S.D.± pre:12.88, post:7.39) reduced apoptosis (P=0.03) and 9% (S.D.±pre:0.339, post:0.237) increased proliferation (P=0.002) compared to those incubated in pre-exercise serum, and further increased by 43% (S.D.±pre:0.256, post:0.367) with serum following 9 days intensive training (P≤0.001).

Summary: Our results suggest exercise protects beta cells from apoptosis and increases their proliferation. Further benefits of exercise on beta cell health, and the mechanisms through which they manifest in T1D need characterisation. This provides a basis to explore exercise as a potential therapy for patients with T1D.