MiPsummer Programme pdf - Mitochondrial Physiology Society

79
Abstract # 47
Insulin sensitivity does not correlate with mitochondrial respiration: Studies in gastric bypass
patients
Lund M.T 1, 2 , M. Hansen 1 , A. Floyd 2 , K. Bech 2 , Helge J 1 . W, F. Dela 1 .
1 Biomedical Sciences, University of Copenhagen, 2 Department of Surgery, Koege Hospital,
Denmark.
Introduction and aim
Obesity and type 2 diabetes are accompanied
by intramyocellular lipid accumulation. It has
been hypothesized that this leads to
mitochondrial dysfunction and insulin
resistance. Our aim was to compare changes in
peripheral insulin sensitivity and
mitochondrial respiration after a diet induced
weight loss and subsequently by a Roux-En-Y
gastric bypass induced weight loss in obese
patients with or without type 2 diabetes (T2D).
Materials and methods:
16 subjects (4M/12F; 6 with (T2DM) and 10 (OB) without T2D) reported thrice to the lab after an
overnight fast: Prior to weight loss (A), 2 mo later just prior to operation (B) and 4 mo after
operation (C). At each visit tree tests were performed: Day 1: DEXA scan for body composition and
a graded bicycle test for VO 2 max. Day 2: Hyperinsulinaemic euglycemic clamp to measure
peripheral insulin sensitivity. A biopsy was taken from m. vastus lateralis for respirometry prior to
the clamp. Muscle fibers were split, permeabilised and transferred to the respirometer.
Results:
Anthropometric data is shown in the table.
Insulin sensitivity measured per fat free mass
(GIR/FFM) and maximally coupled respiration
data are shown in the figure.
Conclusion:
In spite of the marked difference in insulin
sensitivity between OB and T2DM, maximally
coupled mito-chondrial respiration was similar in
the two groups. Moreover, with marked
improvements in T2DM insulin sensitivity, due
to the massive weight loss, mitochondrial
respiration remained unchanged. These results
speak against an association of mitochondrial
respiratory capacity and insulin resistance in
skeletal muscle in OB and T2DM.