Effects of Insulin Glargine and Lixisenatide on the Brain
Status:
Terminated
Trial end date:
2020-06-29
Target enrollment:
Participant gender:
Summary
1. Background During the last years, the brain has been identified as a major
insulin-sensitive organ . The investigators and also other scientists identified
hypothalamus, fusiform gyrus and prefrontal cortex as major insulin-sensitivity brain
areas in humans . Brain insulin action regulates important physiological functions in
humans such as food intake, body weight regulation, and cognition. Furthermore, animal
studies suggest that insulin action specifically in the brain is involved in the control
of peripheral glucose metabolism via regulation of the sensitivity to insulin in the
rest of the body. Recently, the investigators were able to replicate these findings in
humans: The investigators measured whole-body insulin sensitivity in combination with
the well-established experimental delivery of human insulin to the brain via an
intranasal approach. Peripheral insulin sensitivity was profoundly improved by brain
insulin action in lean but not in obese healthy volunteers. What determines the
effectiveness of this brain-derived pathway is still unknown. Furthermore, insulin
resistance of the brain is linked to neurodegenerative diseases possibly explaining the
elevated risk for such diseases in patients with type 2 diabetes.
GLP-1 receptor agonists have been shown to acutely modulate appetite- and reward-related
brain areas in humans. Research in animals suggest a close interaction between insulin
and GLP-1 action especially in homeostatic centers of the hypothalamus. In this context,
it is important that GLP-1 sensitivity of the brain is still present in the insulin
resistant human brain.
The investigators therefore hypothesized that GLP-1 agonists are able to improve insulin
sensitivity of the brain; this might be one mechanism how GLP-1 agonists lead to weight
loss and improved glucose metabolism. This might also have beneficial implications for
cognitive function.
However, at present, there are no human studies examining the effect of a GLP-1 agonist
on brain activity and especially insulin action in the brain in patients with type 2
diabetes mellitus (T2D).
Furthermore, there is no study in humans examining the effect of newly initiated insulin
therapy on brain activity and especially insulin action in the brain in patients with
T2D.
2. Rationale Based on the close interplay between hypothalamic insulin and GLP-1
signalling, the investigators hypothesize that the antidiabetic therapy with insulin
glargine/lixisenatide combination (iGlarLixi) induces improved hypothalamic and
prefrontal insulin sensitivity compared to a therapy with insulin glargine alone. This
could underlay iGlarLixi's beneficial effects on body weight and whole-body glucose
homeostasis.
3. Objective To assess whether treatment with iGlarLixi versus insulin glargine changes
brain regional insulin sensitivity and thereby glucose metabolism, eating behaviour, and
cognition in patients with type 2 diabetes insufficiently controlled with oral
antidiabetic drugs (OAD).