Exploration of the Enteric Nervous System in Alzheimer Disease
Exploration of the Enteric Nervous System in Alzheimer Disease
The close homology between the central and enteric nervous system suggests that a disease
 process affecting the central nervous system could also involve its enteric counterpart. This
 has already been demonstrated for patients with Parkinson's disease but needs to be proven
 for Alzheimer's disease. Studies on enteric nervous system during Alzheimer's disease are
 indeed in low number and don't have led to definite conclusion. The investigators thus
 propose to realize a complete analysis of the enteric nervous systems in Alzheimer's disease
 by studying the presence of "tau' protein, of beta-amyloid peptide,...

 not only by immunohistochemical but also by a biochemical approach. This study will be
 realized from colonic samples.
The close homology between the central and enteric nervous system suggests that a disease
 process affecting the central nervous system could also involve its enteric counterpart. The
 investigators have recently shown in that the enteric neurons can be readily analyzed using
 routine colonic biopsies. The investigators propose that the enteric nervous system could
 represent a unique window to assess the neuropathology in living patients with a
 neurodegenerative disorder. The investigators have already used this approach to show that
 Parkinson's disease pathology was recapitulated in a single colonic biopsy. By contrast to
 Parkinson's disease, the detection of Alzheimer's disease pathology in the enteric neurons
 has so far failed. This may be due to the low number of human tissue samples in addition to
 the low sensitivity of the immunohistochemical methods that were used. The aim of the current
 research project will be therefore to reevaluate Alzheimer's disease pathology in a large
 number of human colonic samples using both a morphological and biochemical approach.

 The Hypothesis is that the enteric nervous system could represent a unique window to assess
 the neuropathology in living patients with Alzheimer's disease. This might open the way to
 the development of novel Alzheimer's disease biomarkers that will directly assess the
 neuropathological process.
Inclusion Criteria:

 -  For the 3 groups of patients : colonoscopy planned by a gastroenterologist in the
 context ot the usual medical follow-up of the patient

 For patients with Alzheimer's disease :

 -  Patient with early to moderate Alzheimer disease (continuum of patients with mild
 cognitive impairment due to Alzheimer's disease and patients diagnosed with probable
 Alzheimer's disease) according to the National Institute of Aging-Alzheimer's
 Association (NIA AA) criteria

 -  Mini-Mental State Examination (MMSE) score ≥18;

 -  Has one informant or care partner;

 -  No parkinsonian syndrome

 -  No sign of lewy Body dementia

 For patients with Parkinson's disease:

 -  patients with Parkinson Disease according to the United Kingdom Parkinson's Disease
 Society Brain Bank (UKPDSBB) criteria

 -  No dementia sign or cognitive deficit associated to Alzheimer's disease

 For patients without neurodegenerative disease:

 -  No history or current neurological/degenerative condition (e.g, lewy body dementia,
 Parkinson's disease, Parkinsonian syndrome, Alzheimer's disease,…)

 -  No memory complaint with a Mac Nair score ≤15

 -  MMSE score ≥28 ;

 -  Patient at risk of colic cancer with a colonoscopy scheduled

 Exclusion Criteria:

 For the 3 groups of patients : :

 -  History of colonic disorder ((e.g inflammatory condition, adenocarcinoma)

 -  contra-indications to colonoscopy

 For patients with Alzheimer's disease and for patients with Parkinson's disease:

 - Any neurological/neurodegenerative condition different from the group to which it belongs
 (e.g other than Alzheimer's disease for Alzheimer's disease group or other than Parkinson's
 disease for Parkinson's disease group….)

 For patients without neurodegenerative disease:

 -  Any neurological/neurodegenerative condition (e.g lewy body dementia, Parkinsonian
 syndrome, Parkinson's disease, Alzheimer's disease..)..

 -  functional colopathy