When fat tissue around the heart and blood vessels from heart failure patients was soaked in a small amount of methylene blue for a day, the levels of a specific enzyme (MAO-A) that makes harmful molecules went down.
Scientific Claim
Incubation of human epicardial and perivascular adipose tissue with 0.1 µM methylene blue for 24 hours is associated with reduced expression of monoamine oxidase A (MAO-A) at both gene and protein levels, as measured by qRT-PCR and immunofluorescence in tissue samples from 25 patients with heart failure.
Original Statement
“Acute incubation of the samples with MB (0.1 µM, 24 h) significantly decreased the expression of both MAO isoforms in human adipose tissue.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The study directly measured MAO-A expression changes in human tissue samples after controlled MB exposure. The design supports definitive language because the observation is confined to the ex vivo tissue model, and the claim reflects only what was measured in that context.
Evidence from Studies
Supporting (1)
Methylene blue reduces monoamine oxidase expression and oxidative stress in human cardiovascular adipose tissue
Scientists tested a blue dye called methylene blue on fat tissue from heart failure patients and found it lowered levels of a harmful enzyme called MAO-A, both in the tissue’s genes and proteins, exactly as the claim says.