Diabetes Bootcamp; Sport intervention in patients with diabetes type 2 and the association with the gut microbiota.

Diet and exercise are the most beneficial and most frequently advised lifestyle
interventions in patients with diabetes mellitus (DM) type 2, causing an
increase in glucose tolerance.
One of the mechanisms through which these treatment modalities work might be
explained through changes in the gut microbiota. Recent studies show that the
chronic inflammatory status causing insulin resistance in DM type 2, is
triggered by an increase in circulating bacterial lipopolysaccharide (LPS).
Research in mice has shown that a high-fat diet alters the gut microbiota
causing an increase in intestinal permeability, resulting in a rise of
circulating LPS. Consequently, LPS causes a low-grade inflammation by inducing
pro-inflammatory cytokines (TNF-alfa, interleukin (IL)-1, and IL-6). Strict
lifestyle intervention (low-fat diet and exercise), so called Diabetes Bootcamp
(DB), may manipulate and reverse the alterations in gut microbiota caused by
high fat diet, ultimately reducing circulating LPS, resulting in an increase in
glucose tolerance.
That the gut microbiota have a causal role in determining insulin sensitivity
in humans was made likely by a faecal transplantation of lean donors to male
recipients with metabolic syndrome. Six weeks after infusion of microbiota from
lean donors, insulin sensitivity of recipients increased along with levels of
butyrate-producing intestinal microbiota. Studies in humans however have so far
not been able to answer the question whether the beneficial effects of these
targeted lifestyle interventions in patients with DM type 2 are due to a change
in gut microbiota.
Also exercise increases the microbial diversity as well as bacterial genes
involved in protein metabolism. These changes in gut microbiota might also be a
cause for increased glucose tolerance.

A second mechanism that has been proposed to attribute to the pathophysiology
of insulin resistance lies within impairments of the hemodynamic effects of
insulin. In healthy subjects insulin enhances the perfusion of skeletal muscle
capillaries by vasodilatation of pre-capillary arterioles. This process is
called capillary recruitment. In patients with DM type 2 insulin-mediated
vasodilatation of the microcirculation is blunted. Animal research suggests a
causal mechanism between decreased microvascular perfusion in skeletal muscle
and decreased glucose uptake. However, evidence from human studies is
incomplete. A low-dose infusion of iloprost * a stable prostacyclin analogue -
is able to increase glucose uptake in type 2 diabetes patients. However, in
this study, capillary recruitment was not assessed and enhancement of capillary
recruitment may well explain the effects of iloprost on glucose uptake.
Furthermore it remains unknown up till now if insulin-mediated microvascular
perfusion defects in DM type 2 are reversible by lifestyle interventions and if
improvement of perfusion contributes to lifestyle-dependent control of glucose
uptake.
Finally, there appears to be a correlation between capillary recruitment and
systemic inflammation. In rats, acute administration of TNF-* in vivo
completely blunts the insulin-mediated capillary recruitment and simultaneously
reduces insulin-mediated glucose uptake.

In summary, dietary- and exercise can manipulate the gut microbiota and may
also restore insulin-mediated microvascular perfusion defects in patients with
DM type 2. However, studies in humans have so far not been able to answer the
question whether the beneficial effects of these targeted lifestyle
interventions in patients with DM type 2 are due to a change in gut microbiota
and/or restoration of perfusion defects (capillary recruitment). We thus
hypothesize that through exercise we can manipulate the intestinal microbiota
in patients with DM type 2, causing a reduction in LPS exposure and therefore
pro-inflammatory cytokines. By observing the dynamical changes of the
microbiota during exercise, we will gain more insight in to the complex
relationship between DM type 2, the gut microbiota and lifestyle interventions.

Primary Objective:
To investigate whether exercise (Diabetes Bootcamp) induces a change in
intestinal faecal microbiota (rise of butyrate-producing intestinal microbiota)
related to improved glycaemic control (peripheral and hepatic insulin
sensitivity) in patients with DM type 2.

Secondary Objective(s):
1. To investigate whether changes in gut microbiota induced by an exercise
regimen are associated with changes in plasma markers of systemic inflammation
(CRP/cytokines/LPS), body composition and REE.
2. To demonstrate that an exercise regimen in type 2 diabetic patients results
in improved insulin sensitivity and enhancement of insulin-mediated capillary
recruitment.
3. To investigate whether an exercise regimen induces a change in
insulin-mediated capillary recruitment related to systemic inflammation in
patients with DM type 2.
4. To investigate whether infusion of iloprost in type 2 diabetes patients is
able to increase glucose uptake and reveals capillary recruitment. To
demonstrate that acute infusion of iloprost * a stable prostacyclin analogue *
in type 2 diabetic patients results in enhanced improved insulin sensitivity
and enhancement of insulin-mediated capillary recruitment.,
5. To investigate whether an iloprost infusion is able to simulate the effects
of a exercise regimen on capillary recruitment and insulin sensitivity.
6. Characterization of PVAT morphology, adipokine profile and function before
and after an exercise program.
7. To demonstrate the effects of acute iloprost infusion and an exercise
regimen on:
* Adipose tissue and myocardial perfusion.
* RMR, oxidation of macronutrients (Quark®)
* Blood pressure, heart rate, heart rate variability, peripheral vascular
resistance and cardiac output.

Patients with diabetes type 2 will be included in a prospective open-label
study.
After screening, patients will participate in a full exercise program (twice a
week, one hour), guided by a physiotherapist.
There will be 5 study visits: 2 baseline visits as well as control visits at 7,
12 and 26 weeks. There will be a 3-day deviation for all return visits. All
assessments, including clinical evaluation, safety and biomarker measurement,
will be performed at each visit. At baseline and week 12 blood samples, fecal
analysis, hyperinsulinemic-euglycemic clamp, indirect calorimetry (REE), Bio
Impedance Analysis (BIA), muscle biopsy as well as contrast-enhanced ultrasound
(CEUS) measurements will be performed. At baseline, all participants visit the
research center on 2 consecutive days to undergo a hyperinsulinemic-euglycemic
clamp with and without iloprost infusion. The order of the first 2 days will be
randomized.

During a 12 week period patients will participate in a full exercise program.

After screening, patients will participate in a full exercise program during a
period of 12 weeks, called Diabetes Bootcamp (DB). The exercise program is
twice a week during 1 hour, matched to their own personal capacity.
There will be 5 study visits: 2 baseline visits as well as control visits at 7,
12 and 26 weeks. All assessments, including clinical evaluation, safety and
biomarker measurement, will be performed at each visit. At baseline and week 12
blood samples, fecal analysis, an hyperinsulinemic-euglycemic clamp, indirect
calorimetry (REE), Bio Impedance Analysis (BIA), muscle biopsy as well as
contrast-enhanced ultrasound (CEUS) measurements will be performed. At
baseline, all participants visit the research center on 2 consecutive days to
undergo a hyperinsulinemic-euglycemic clamp with and without iloprost infusion.

Risks associated with hyperinsulinaemic-euglymic clamps are hypo-or
hyperglycemia, which we will prevent by adjusting pump levels. Iloprost
infusion is known to have some side effects, but non are severe at a low dose.
The placing of the intravenous cannula in our study can be an unpleasant
experience for the subjects. There is a low risk of flebitis at the intravenous
injection sites, this is unpleasant, but not harmful, of temporary nature and
self-limiting. Muscle and fat biopsies require a local anesthesia, which can
give some discomfort to the participants. Also, after the biopsy participants
can expect some muscle ache.

We expect great health benefits for the participants, including weight
reduction, an increase in exertion and glucose tolerance. This research can be
classified as low risk and will hopefully provide mechanistic insight into
whether it is the intestinal microbiota are related to human satiety and
metabolism, which may help us to develop therapeutic methods to combat obesity
and insulin resistance.