When fat tissue around the heart and blood vessels was soaked in a blue dye called methylene blue for a day in the lab, it made less of a harmful enzyme and produced fewer damaging chemicals, which might help explain how the dye could protect cells.
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) protein and mRNA, as well as decreased production of superoxide and hydrogen peroxide, suggesting MAO-A is a major source of oxidative stress in these tissues.
Original Statement
“Incubation with MB reduced MAOs expression and oxidative stress; ... Acute incubation of the samples with MB (0.1 µM, 24 h) significantly decreased the expression of both MAO isoforms in human adipose tissue ... ROS production ... was significantly reduced in the presence of MB in both types of adipose tissues.”
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 design (ex vivo tissue incubation) allows definitive statements about direct effects observed in the isolated tissue under controlled conditions. The claim accurately reflects what was measured without extending to in vivo or clinical effects.
Evidence from Studies
Supporting (1)
Methylene blue reduces monoamine oxidase expression and oxidative stress in human cardiovascular adipose tissue
Scientists found that adding a small amount of methylene blue to fat tissue around the heart and blood vessels lowered a harmful enzyme (MAO-A) and reduced damaging chemicals called free radicals, suggesting methylene blue can help calm oxidative stress in these tissues.