Exercise in An Islet-Transplanted Amateur Marathon Runner: Effects on Training, Autoimmunity and Metabolic Profile

Abstract

Introduction: Type 1 diabetes mellitus (T1DM) is a chronically progressive autoimmune disease in which the adverse immune response is induced and promoted by the interaction of genetic and environmental factors. Recent studies have suggested that physical exercise may interfere with immune system function even at low intensity and duration. Methods: An islet-transplanted T1DM patient (M, 44yrs) has been longitudinally monitored for autoimmunity markers, metabolic profile and physical performance, being himself an amateur marathon runner, over a 7-year period since he received an islet allograft. Given his irregular history of training (because of injuries, medical issues etc), we identified 4 phases throughout this period, lasting 2 years each, alternating between phases of rest and training. Results: An ad hoc regime of training (supervised interval training) resulted in an improvement in HbA1c (-9.2%, p< 0.05), C-reactive protein (-16.6%, p< 0.05) and a decrease of exogenous insulin (from 4-8 to 4-6 U/day) during the 2nd phase compared to the 1st phase of rest (recovery after allograft). In the 3rd phase (post-injury resting), Hb1Ac increased by 13.3% (p< 0.05 vs 2nd phase), as did the insulin dose (6-8 U/day). In the 4th phase, exercise training was accompanied by an amelioration of Hb1Ac of 22% compared to the 3rd phase, and the number of required insulin units diminished dramatically vs the 1st phase (2-3 U twice a week), as did the levels of autoimmunity markers (antiGAD and antiINS ab, from 0.5 to 0.0 and from 6.6 to 1.6 AU, respectively). Race time during competition improved by 10.5% vs the 2nd phase of training (p< 0 .05). Also in the 4th phase, aerobic, anaerobic thresholds and heart rates were significantly higher than in the previous phases (p< 0.05). Conclusions: Altogether, these data suggest an association between the alterations in detrimental metabolic and autoimmunity profiles and the successive training/resting periods, evoking a potential role for exercise in the positive immunomodulation against T1DM progression and inflammation.