Carbon dioxide pulses may increase brain clearance in Parkinson's study

A proof-of-concept study reported that brief, rhythmic increases in inhaled carbon dioxide altered cerebrospinal fluid flow and raised blood markers of brain waste in older adults, including people with Parkinson's. Whether these changes persist or affect disease progression remains unknown.

Researchers at the University of New Mexico and The Mind Research Network tested whether short, repeated rises in inhaled carbon dioxide (intermittent hypercapnia) can change the brain's cerebrospinal fluid circulation and clearance of waste. The work combined MRI measures and blood sampling in older adults, some of whom had Parkinson's disease, to look for acute changes in flow and waste markers. The team reports altered cerebrospinal fluid movement and increased levels of brain-derived waste products in blood after the interventions. The authors note that it is not yet known if these changes are lasting or if they change disease outcomes. Key findings: - The study included 63 older adults (about 30 with Parkinson's) who underwent MRI during brief cycles of elevated inhaled CO2, and a smaller experiment with 10 participants (about 5 with Parkinson's) that measured blood markers after sessions. - Researchers reported that intermittent hypercapnia altered cerebrospinal fluid flow and was associated with increased indicators of glymphatic clearance and higher levels of some brain-derived proteins in plasma. - The study's authors say the results are a proof of concept and that it is unclear whether these effects are sustained or modify disease; they are now investigating whether abdominal-breathing practices affect CO2 and clearance similarly. Summary: The study reports short-term changes in cerebrospinal fluid movement and elevated blood markers of brain waste after intermittent CO2 exposure in small groups including people with Parkinson's. Undetermined at this time is whether these changes last or influence the course of neurodegenerative disease, and researchers are pursuing further studies on breathing practices and clearance.