New Findings on Human Pegavirus
Recent research reveals a concerning link between a prevalent virus and Parkinson’s disease. Scientists at Northwestern Medicine uncovered unusually high levels of human pegavirus (HPgV) in the brains of individuals suffering from Parkinson’s, suggesting a possible contributing factor to the condition.
The team examined brain tissue from both Parkinson’s patients and control subjects, discovering remnants of HPgV in 50% of the brains afflicted with the disease, while none of the control brains exhibited any trace of the virus.
Immune Response and Genetic Factors
Patients carrying the virus displayed distinct immune responses and advanced neurological changes further compounded by genetic mutations. Parkinson’s disease, characterized by the gradual deterioration of dopamine-producing neurons, leads to symptoms such as tremors, stiffness, and impaired movement.
The analysis indicated that those with HPgV present in their brains experienced more extensive brain damage. Patients with the virus detected in their blood demonstrated further signs of cellular distress, struggling to produce energy and clear damaged components within the brain.
Dr. Igor Koralnik, an expert in neuroinfectious diseases at Northwestern Medicine, commented on the findings: ‘For a virus that was thought to be harmless, these findings suggest it may have important effects, in the context of Parkinson’s disease. It may influence how Parkinson’s develops, especially in people with certain genetic backgrounds.’
The Mystery of Parkinson’s
Parkinson’s disease impacts approximately one million Americans, causing significant challenges in mobility and cognition. While the precise cause remains elusive, researchers continue to investigate various contributors, including viral agents.
When the brain detects a virus, it initiates an inflammatory response to combat the infection. However, chronic inflammation can inadvertently harm vulnerable brain cells, including those responsible for dopamine production.
Methodology of Study
The research utilized a library of biological samples from over 1,000 participants involved in the Parkinson’s Progression Markers Initiative (PPMI), a project initiated by The Michael J. Fox Foundation aimed at accelerating studies into Parkinson’s research. Brain tissue from 24 deceased individuals was analyzed, revealing the virus’s presence in half of the Parkinson’s cases.
Transmission and Frequency of HPgV
HPgV is commonly transmitted through blood, often shared via needles or historically through transfusions prior to extensive screening. Currently, studies estimate that around 4% of Americans actively carry HPgV, with up to 12% having been exposed at some point in their lives.
Notably, patients with the LRRK2 gene mutation associated with Parkinson’s exhibited a more vigorous immune response to HPgV than those without the mutation. This heightened response led to harmful inflammation in the brain, resulting in neuronal damage characteristic of Parkinson’s disease.
Impact on Brain Health
Dr. Koralnik expressed surprise at the high frequency of HPgV in Parkinson’s patients, stating: ‘We were surprised to find it in the brains of Parkinson’s patients at such high frequency and not in the controls.’ He noted the unexpected variability in immune responses linked to individual genetics, indicating a possible environmental interaction that merits further investigation.
Additionally, the virus was detected in the spinal fluid of Parkinson’s patients but absent in controls. This connection raises further questions about the role of HPgV in the degenerative process affecting dopamine-producing cells, particularly in the substantia nigra region of the brain.
Indicators of Disease Progression
Patients harboring the virus also had higher levels of toxic tau protein and irregular concentrations of essential brain proteins, pointing towards advanced disease progression. The presence of tau pathology signifies widespread brain dysfunction beyond the loss of dopamine neurons, which is typically seen in Parkinson’s.
The findings were published in the journal JCI Insight and underscore the limited effectiveness of current Parkinson’s treatments, which primarily offer symptomatic relief rather than a cure. Levodopa (L-Dopa) remains the gold standard treatment, converting into dopamine to alleviate core movement symptoms.
With approximately 10 million individuals diagnosed with Parkinson’s globally—including about one million in the U.S.—the figure is projected to rise to over 25 million by 2050. Dr. Koralnik concluded: ‘We plan to look more closely at how genes like LRRK2 affect the body’s response to other viral infections to figure out if this is a special effect of HPgV or a broader response to viruses. One big question we still need to answer is how often the virus gets into the brains of people with or without Parkinson’s.’
