1) Determine whether humanized mice develop enhanced restenosis upon vascular injury after reconstitution with human PBMCs derived from T2DM subjects with or without macrovascular disease.2) Determine what mechanism(s) induces deranged vascular…
ID
Source
Brief title
Condition
- Coronary artery disorders
- Diabetic complications
- Arteriosclerosis, stenosis, vascular insufficiency and necrosis
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
From the peripheral blood obtained PBMCs will be isolated using Ficoll density
gradient centrifugation. Isolated cells will then be subjected to:
1) Flowcytometric analyses: These phenotypic analyses allows quantification
circulating endothelial and smooth muscle progenitor cells (EPCs and SMPCs,
respectively) in the peripheral blood of diabetic and non-diabetic subjects and
correlate frequencies of these specific cell subsets to the presence of
cardiovascular disease.
2) Injury to the arterial wall triggers smooth muscle cell proliferation,
migration and matrix secretion. The resultant intimal hyperplasia is a common
histological finding in restenosis after balloon angioplasty and other arterial
occlusive diseases. We will induce arterial injury in human arterial grafts
which have first been transplanted into the abdominal aorta of immunodeficient
mice.
The results from these in vivo experiments will reveal whether the humanized
model reflects the clinical situation of the individuals providing the tissues.
T2DM is expected to impair endothelial and medial smooth muscle cell function
in the vascular wall and this may in turn influence the response of vascular
progenitor cells upon vascular damage. Therefore, mice reconstituted with
cells/tissues obtained from T2DM subjects likely develop more severe restenosis
than mice transplanted with cells/tissues derived from non-diabetic controls.
In order to analyze whether exposure of PBMCs and arterial grafts derived from
non-diabetic individuals to a T2DM environment influences their behaviour in
response to vascular injury we will adapt our humanized mouse model by
developing a humanized mouse model which has a diabetic background. We will
transfer non-diabetic PBMCs to both non-diabetic and T2DM immunodeficient
recipient mice that receives an arterial transplant. After arterial injury, the
severity of restenosis will be determined. The results from these experiments
will reveal whether vascular progenitor cells derived from non-diabetic
individuals will adapt to a diabetic phenotype in vivo and whether this
adaptation is permanent or reversible.
Secondary outcome
n.a
Background summary
Individuals with Type 2 diabetes mellitus (T2DM) have increased rates of
cardiovascular disease including peripheral artery disease (PAD) and coronary
artery disease (CAD) as well as restenosis after previous intervention.
Development of cardiovascular disease in diabetic patients remains a major
source of morbidity and mortality. A common approach for the prevention and
treatment of cardiovascular disease in diabetes relies on the understanding of
its complex pathophysiology. As yet, the underlying molecular mechanisms of
increased cardiovascular disease in T2DM are still unclear but may involve
aberrant vascular progenitor cell function. Vascular progenitor cells include
endothelial progenitor cells (EPCs) and smooth muscle progenitor cells (SMPCs).
We have recently started to recruit and include patients (METc 2008/335)
whereby blood is collected for in vitro experiments. These experiments will
determine differences in EPC and SMPC availability in the peripheral blood of
T2DM patients with and without CAD or PAD (i.e. atherosclerosis in carotid
artery and/or lower extremities) as well as in age- and sex-matched
non-diabetic control subjects. Moreover, the molecular and functional
differences in EPCs and SMPCs between these groups will be determined.
Since our goals imply translation of the obtained results towards the human
T2DM patient, we propose to use human cells and arteries (from T2DM and
non-diabetic controls with and without arterial disease) in a mouse host
environment (i.e. the use of humanized mice). Such a model system enables
studies on human cells that interact with the human vascular wall in vivo, but
thereby also allowing interventions and analyses that are not feasible in the
living human body.
Study objective
1) Determine whether humanized mice develop enhanced restenosis upon vascular
injury after reconstitution with human PBMCs derived from T2DM subjects with or
without macrovascular disease.
2) Determine what mechanism(s) induces deranged vascular progenitor cell
frequency and function and whether this is permanent or reversible.
These objectives will reveal causal relationships between deranged vascular
progenitor cell frequency and behaviour in individuals with T2DM and the
relative risk to develop macrovascular disease. In addition, we will determine
at which stage of the T2DM disease process vascular progenitor cells develop
their aberrant phenotype, and whether these adaptations are permanent once
induced, or whether they can be reversed.
Study design
In the current study, 4 different groups of patients will be included:
1) T2DM, no CAD (without PAD)
2) T2DM, with CAD (with or without PAD)
3) no T2DM, no CAD (without PAD)
4) no T2DM, with CAD (with or without PAD)
Arterial grafts are preferentially derived from side-branches of the left
internal mammary artery (LIMA) or mesenteric arteries because of similarities
in size of these arteries and the mouse aorta. PBMCs and arterial tissue (LIMA)
from groups 2 (T2DM) and 4 (non-diabetic) will be obtained from patients in
need of bypass surgery because of CAD. Mesenteric material and blood from
groups 1 and 3 will be available from patients requiring abdominal surgery. In
addition, arterial material becoming available during reconstructive surgery
will be used. Arterial material which would normally be disposed of, will be
kept in sterile saline for our studies. Blood will be collected for standard
pre-operative laboratory analysis, 5 extra tubes of blood (in total 50ml) will
be collected for our studies. The peripheral blood will be collected in 4x 10ml
EDTA vacutainer tubes (K3E 15% 0.12ml) and 1x SST vacutainer tube.
Study burden and risks
The nature of the research is such that participation entails no inherent risk
for the subject. The extent of the burden is relatively low, donation of 50 ml
peripheral blood and arterial material which is normally removed during surgery
and would otherwise be disposed of as biological waste. Participants of the
study will not have immediate benefit from the outcome of the study.
Hanzeplein 1
PO Box 30.001 9700 RB Groningen
NL
Hanzeplein 1
PO Box 30.001 9700 RB Groningen
NL
Listed location countries
Age
Inclusion criteria
Patients eligible for participation are diagnosed with T2DM (duration 10-15 yrs) and divided into diabetic patients with CAD or without cardiovascular disease. Patients eligible for participation in the various control groups are patients without a history of T2DM but with CAD, respectively. In addition, healthy individuals who have neither a history of diabetes, cardiovascular disease, inflammatory or autoimmune disease, nor obesity nor any other chronic disease are will be included. Definition of CAD: Coronary artery disease (CAD) CAD is defined as previous myocardial infarction, resting ECG indicative of past MI, positive ECG at exercise stress test, echocardiography stress-test positive for inducible ischemia, evidence of significant coronary artery stenose on angiography with or without typical chest pain. Participants allocated to the different groups will be matched for: - gender - age - smoking - BMI - arterial hypertension - HbA1c (diabetics) - lipid profile
Exclusion criteria
Predefined exclusion criteria for T2DM include diagnosis of T1DM and presence of any of the following (self-reported) medical conditions: - auto-immune diseases - acute or chonic infection - age >80yrs - hemodialysis - immunosuppression - any other unrelated disease. Exclusion criteria for non-diabetics include: - diagnosis of T1DM or T2DM - auto-immune diseases - acute or chonic infection - age >80yrs - hemodialysis - immunosuppression - any other unrelated disease .
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL32431.042.10 |