Study Links Common Infections to Increased Alzheimer’s Risk

Recent research suggests that two common infections may contribute to the development of Alzheimer’s disease, raising concerns about public health. A review conducted by the Philadelphia College of Osteopathic Medicine in Pennsylvania indicates that both chlamydia pneumoniae and SARS-CoV-2 could elevate levels of cytokines in the brain, leading to inflammation that may accelerate the buildup of harmful proteins linked to Alzheimer’s.

The findings, published in the journal Frontiers in Aging Neuroscience, highlight the role of these infections in triggering inflammatory responses. Specifically, researchers identified that both pathogens can invade the central nervous system via the blood-brain barrier and the olfactory route, which is associated with the sense of smell. The olfactory system is particularly vulnerable as it is lined with specialized tissue that can facilitate pathogen entry into the brain.

Researchers noted that the initial infection of these microbes can travel along the olfactory nerves to the brain’s olfactory bulbs, which connect to areas responsible for memory and cognition. This pathway might explain why loss of smell is an early symptom of both COVID-19 and Alzheimer’s disease.

Dr. Brian J Balin, a professor of neuroscience and neuropathology, stated, “These findings bring us one step closer to understanding the complex interactions between infections and Alzheimer’s disease. As we continue to learn more about the role infectious agents play in the development of this disease, we hope to create new avenues for prevention and treatment.”

In assessing the risk factors for Alzheimer’s, the study focused on patients carrying genetic predispositions, particularly the APOE4 variant. This protein plays a crucial role in transporting fatty molecules, and having one copy of the APOE4 variant doubles or triples the risk of developing Alzheimer’s. Those with two copies face an eight to twelve times higher risk. Approximately one in fifty people carry two copies of APOE4.

The study also explored cytokines such as IL-6 and CCL2, which are integral to inflammation and immune responses. Individuals with the APOE4 variant appeared more susceptible to both chlamydia pneumoniae and SARS-CoV-2, suggesting a potential amplification of their Alzheimer’s risk.

Alzheimer’s disease is characterized by the abnormal accumulation of proteins, including amyloid plaques and tau tangles, which disrupt communication between brain cells. Though the exact causes remain unclear, several factors are known to increase the likelihood of developing this condition. These include age, family history, and lifestyle factors such as obesity, smoking, and diabetes.

According to Alzheimer’s Research UK, approximately 980,000 people in the UK are currently living with dementia, a number expected to exceed 1.4 million by 2040. Alzheimer’s is the most prevalent form of dementia, accounting for 60 to 80 percent of cases.

Symptoms typically develop gradually and may initially be mistaken for age-related memory decline. Common early signs include difficulty remembering recent events, repeating questions, and challenges in following conversations. As the disease progresses, individuals may experience confusion about time or place, misplacing items, and increased anxiety or agitation.

If you or a loved one are experiencing symptoms indicative of Alzheimer’s, it is advisable to consult a healthcare professional. While no cure exists, there are treatment options available to help manage symptoms and improve quality of life.

The implications of this research extend beyond academic interest, as understanding the relationship between infections and Alzheimer’s could open new pathways for prevention and therapeutic strategies.