Researchers Find Damaged Nasal Tissue Could Allow Bacteria Into the Brain, Contributing to Alzheimer’s

Dual Chlamydia pneumoniae labeling and Thioflavin S staining of the temporal cortex from an AD brain

Image Credit: Springer Nature

The 2022 Scientific Reports study examined the process by which Chlamydia pneumoniae enters the central nervous system (CNS) and its possible role in Alzheimer’s disease development. The researchers discovered that mice developed CNS infections from intranasal exposure to bacteria which traveled through olfactory and trigeminal nerves to reach the olfactory bulb and brain within 72 hours. The research showed that infected mice developed amyloid beta deposits which formed near bacterial inclusions throughout their olfactory system thus indicating a potential link between bacterial infection and Alzheimer’s disease development. The bacteria C. pneumoniae demonstrated the ability to infect peripheral nerve cells and CNS glial cells in laboratory tests which suggests these cells could serve as bacterial reservoirs. The study revealed that nasal epithelial damage led to increased bacterial spread throughout peripheral nerves and olfactory bulb tissue but did not affect the total amount of CNS infection. The bacteria C. pneumoniae uses particular nerve routes to quickly penetrate the CNS which might play a role in Alzheimer’s disease progression.

Reference: Read et al. (2022). Chlamydia pneumoniae can infect the central nervous system via the olfactory and trigeminal nerves and contributes to Alzheimer’s disease risk. Scientific Reports, 12, 2547. https://doi.org/10.1038/s41598-022-06749-9

Further Reading:

Hammond, C. J., Hallock, L. R., Howanski, R. J., Appelt, D. M., Little, C. S., & Balin, B. J. (2010). Immunohistological detection of Chlamydia pneumoniae in the Alzheimer’s disease brain. BMC Neuroscience, 11, 121. https://doi.org/10.1186/1471-2202-11-121

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