Hyperbaric oxygen effect on MMP-9 after a vascular insult

Area of Science:

• Biochemistry and Molecular Biology
• Physiology
• Hyperbaric Medicine

Background:

• Matrix metalloproteinase-9 (MMP-9) is implicated in various pathological conditions, including cerebral ischemia, non-healing wounds, and atherosclerosis.
• Overexpression of MMP-9 contributes to adverse outcomes in acute and chronic diseases.
• Hyperbaric oxygen (HBO) therapy's effect on MMP-9 expression requires further investigation, particularly in acute settings.

Purpose of the Study:

• To investigate the acute effects of hyperbaric oxygen (HBO) therapy on matrix metalloproteinase-9 (MMP-9) expression.
• To determine the speed and magnitude of MMP-9 response to HBO in a post-surgical model.

Main Methods:

• A single patient undergoing elective surgery served as her own control.
• MMP-9 levels and urine pH were measured at baseline, and post-operatively before and after daily HBO treatments (100% O2 at 2.5 ATA for 60 min) for 5 days.
• Serial blood samples were collected on post-operative days 1, 3, and 4.

Main Results:

• Post-surgical MMP-9 levels were dramatically elevated (400% increase from baseline).
• Each HBO exposure resulted in a significant reduction in MMP-9 expression.
• Reductions ranged from 46% on post-op day 1 to 30% on post-op day 4, with the greatest decrease observed after the first exposure.

Conclusions:

• This case study suggests that timely HBO therapy following vascular or tissue insult can effectively reduce MMP-9 expression.
• HBO treatment may offer a therapeutic strategy to mitigate chronic vascular pathologies like atherosclerotic plaque instability and reduce risks of acute coronary syndrome or cerebral vascular accidents.
• Further research is needed to elucidate the mechanisms by which HBO modulates MMP-9 and its role in both physiological and pathological processes.