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Published on: December 26, 2016
Polymicrobial Infections In Brain Tissue From Alzheimer's Disease Patients
Diana Pisa1, Ruth Alonso1, Ana M Fernández-Fernández1
1Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), c/Nicolás Cabrera, 1, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain.
Abstract:
Several studies have advanced the idea that the etiology of Alzheimer's disease (AD) could be microbial in origin. In the present study, we tested the possibility that polymicrobial infections exist in tissue from the entorhinal cortex/hippocampus region of patients with AD using immunohistochemistry (confocal laser scanning microscopy) and highly sensitive (nested) PCR. We found no evidence for expression of early (ICP0) or late (ICP5) proteins of herpes simplex virus type 1 (HSV-1) in brain sections. A polyclonal antibody against Borrelia detected structures that appeared not related to spirochetes, but rather to fungi. These structures were not found with a monoclonal antibody. Also, Borrelia DNA was undetectable by nested PCR in the ten patients analyzed. By contrast, two independent Chlamydophila antibodies revealed several structures that resembled fungal cells and hyphae, and prokaryotic cells, but most probably were unrelated to Chlamydophila spp. Finally, several structures that could belong to fungi or prokaryotes were detected using peptidoglycan and Clostridium antibodies, and PCR analysis revealed the presence of several bacteria in frozen brain tissue from AD patients. Thus, our results show that polymicrobial infections consisting of fungi and bacteria can be revealed in brain tissue from AD patients.
Insights
This study investigated microbial causes of Alzheimer's disease (AD). Researchers found evidence of fungal and bacterial infections in AD brain tissue, suggesting a polymicrobial origin for the disease.
Area of Science:
- Neuroscience
- Microbiology
- Pathology
Background:
- Emerging research suggests a potential microbial etiology for Alzheimer's disease (AD).
- Investigating specific pathogens in AD brain tissue is crucial for understanding disease mechanisms.
Purpose of the Study:
- To determine the presence of polymicrobial infections in the entorhinal cortex/hippocampus of Alzheimer's disease patients.
- To utilize immunohistochemistry and nested PCR to detect microbial agents.
Main Methods:
- Immunohistochemistry with specific antibodies (HSV-1, Borrelia, Chlamydophila, peptidoglycan, Clostridium).
- Confocal laser scanning microscopy.
- Highly sensitive nested PCR for microbial DNA detection.
- Analysis of brain tissue from Alzheimer's disease patients.
Main Results:
- No evidence of herpes simplex virus type 1 (HSV-1) proteins was found.
- Antibodies against Borrelia detected fungal-like structures, and Borrelia DNA was undetectable.
- Chlamydophila antibodies indicated structures possibly unrelated to Chlamydophila spp.
- Evidence of fungal and bacterial presence was detected using peptidoglycan and Clostridium antibodies, with PCR confirming bacteria.
Conclusions:
- The study revealed evidence of polymicrobial infections, including fungi and bacteria, in the brain tissue of Alzheimer's disease patients.
- These findings support the hypothesis that microbial agents may play a role in the pathogenesis of Alzheimer's disease.
