Bacteria Chlamydia pneumoniae, possibly linked to the onset of Alzheimer's disease

A recent study conducted by the team at Cedars-Sinai Medical Center has discovered a link between the Chlamydia pneumoniae bacteria, commonly found in respiratory infections, and cognitive decline associated with Alzheimer's disease. Analyzing samples of ocular and brain tissue from 104 individuals, researchers identified a significant association between the presence of the bacteria in the retina and the diagnosis of Alzheimer's. Higher concentrations of the bacteria were correlated with more severe cognitive decline, especially in individuals with variants of the APOE gene, associated with an increased risk of Alzheimer's.

Experiments on neurons and animal models have shown that infection with Chlamydia pneumoniae leads to inflammation, cognitive decline, and cell death. Additionally, the presence of the bacteria has been correlated with higher levels of beta-amyloid protein, involved in Alzheimer's pathology. The authors emphasize that, although a direct causal relationship is not demonstrated, there is a strong link between bacterial infection and neurodegenerative processes. The study suggests that the retina may reflect brain changes, opening the possibility of using ocular investigations as non-invasive methods for assessing Alzheimer's risk. The results were published in the journal Nature Communications.