Microbiome and Dementia

The Gut-Brain Axis in Dementia: Biomarker and Novel Intervention Strategies


Lead Sponsor: Medical University of Graz

Source Medical University of Graz
Brief Summary

From this study, it is hoped to learn if and how the gut microbiome composition, gut permeability and inflammation in patients with dementia are associated with each other. Dysbiosis may lead to an increased gut permeability, bacterial translocation and inflammation which may influence pathogenesis and progression of dementia.

The novel aspect of the study will be to understand the association between gut microbiome composition, gut permeability and the presence of dementia. This will help to better understand the pathogenesis of dementia and lead to the development of novel therapeutic strategies. If this hypothesis holds true, the study will be the basis to develop new treatment options for dementia.

Detailed Description

Dementia is a disease that presents with deterioration in memory, thinking, behaviour and the ability to perform everyday activities. Worldwide 47.5 million people are affected and incidence of dementia is increasing. Dementia leads to disability and dependency among older people worldwide and thereby has a huge physical, psychological, social and economic impact on caregivers, families and society. Alzheimers disease (AD) is the most common form of dementia accounting for 60-70% of the cases; other forms include Lewy body dementia, frontotemporal dementia, vascular dementia and Parkinsons disease with dementia. In AD, pathologic protein aggregates of amyloid beta and hyperphosphorylated tangles of tau-protein which deposit as neurofibrillary tangles are typical features. This leads to neuroinflammation, mainly mediated by the innate immune system. The most important cells in this process are microglia cells, which represent the resident macrophages of the brain. Although microglia is able to remove extracellular amyloid beta, in later stages of the disease cells remain in a dystrophic state and cannot exert their beneficial functions. Microglia maturation and function is critically dependent on short-chain fatty acids produced by the gut microbiome and therefore highlights the microbiome as a potential diagnostic and therapeutic target in dementia.

The role of the commensal microbial population of the human body - especially the intestinal microbiome - in various diseases is emerging due to the development of advanced analysis techniques. Recently the concept of the gut brain-axis has been established. Several pathways including the autonomic nervous system, the enteric nervous system, the neuroendocrine system and the immune system allow a communication between gut and brain but may also be involved in disease development.

During ageing, the gut microbiome composition undergoes changes. A decrease in diversity, a loss of beneficial taxa and an increase of facultative pathogens has been described. Diet and the place of residence play an important role in the shaping of the microbiome. Aging is also associated with inflammation - often termed as "inflammaging" associated with an increase in gut permeability, mucosal inflammation and bacterial translocation.

Since the main risk factor for developing dementia, especially AD, is aging, it is very likely that the gut-brain axis is critically involved in dementia development.

Animal studies so far suggest that AD is associated with changes in the gut microbiome composition with a decrease in beneficial, anti-inflammatory genera. Furthermore, genetic alterations in amyloid genes can influence microbiome composition in mice, pointing towards a vicious cycle in AD development.

In humans, so far no studies on the gut microbiome composition in patients with dementia have been published. However, there is evidence that the composition of the microbiome in subgingival plaques is altered in dementia and associated with cognitive function.

Overall Status Completed
Start Date July 7, 2017
Completion Date July 16, 2020
Primary Completion Date July 2, 2018
Study Type Observational
Primary Outcome
Measure Time Frame
Alpha diversity single measurement at baseline
Secondary Outcome
Measure Time Frame
gut permeability single measurement at baseline
bacterial translocation single measurement at baseline
inflammation single measurement at baseline
Enrollment 43

Sampling Method: Non-Probability Sample


Inclusion Criteria:

- Age >18y

- Dementia (Alzheimer type and mixed type)

- Informed consent signed by the patient or his legal representative

- Mini Mental State Examination ≤ 26

Exclusion Criteria:

- Other forms of dementia

- Inflammatory bowel diseases

- Liver cirrhosis

- Antibiotic treatment within the last 14 days

- Any other condition or circumstance, which, in the opinion of the investigator, would affect the patient's ability to participate in the protocol

Healthy controls

- Age >18y

- Informed consent

- No known acute or chronic illness

Gender: All

Minimum Age: 18 Years

Maximum Age: N/A

Healthy Volunteers: Accepts Healthy Volunteers

Facility: Medical University of Graz
Location Countries


Verification Date

July 2020

Responsible Party

Type: Sponsor

Has Expanded Access No
Condition Browse
Arm Group

Label: dementia

Description: patients with dementia

Label: control

Description: healthy control

Patient Data No
Study Design Info

Observational Model: Case-Control

Time Perspective: Prospective

Source: ClinicalTrials.gov