Angiotensin 1-7 protects against ventilator-induced diaphragm dysfunction

Area of Science:

• Physiology
• Biochemistry
• Critical Care Medicine

Background:

• Mechanical ventilation (MV) can cause ventilator-induced diaphragm dysfunction (VIDD), characterized by inspiratory muscle weakness.
• VIDD pathogenesis involves oxidative stress and accelerated proteolysis in diaphragm fibers, hindering patient weaning from MV.
• Current strategies to prevent VIDD are lacking, necessitating the development of novel therapeutic approaches.

Purpose of the Study:

• To investigate the protective effects of the nonclassical renin-angiotensin system (RAS) pathway, specifically angiotensin 1-7 (Ang1-7), against VIDD.
• To determine if Ang1-7 can mitigate MV-induced diaphragmatic atrophy and contractile dysfunction.
• To elucidate the mechanisms by which Ang1-7 exerts its protective effects, focusing on oxidative stress and protease activation.

Main Methods:

• Utilized an established animal model of prolonged mechanical ventilation.
• Administered Ang1-7 via infusion to assess its impact on diaphragm function and structure.
• Evaluated diaphragm muscle fibers for contractile properties, atrophy, mitochondrial damage, oxidative stress markers, and protease activation.

Main Results:

• Infusion of Ang1-7 significantly protected the diaphragm against MV-induced contractile dysfunction and fiber atrophy in both fast and slow muscle fibers.
• Ang1-7 treatment shielded diaphragm fibers from MV-induced mitochondrial damage and reduced oxidative stress.
• Ang1-7 administration diminished protease activation within diaphragm fibers, a key factor in VIDD development.

Conclusions:

• Angiotensin 1-7 (Ang1-7) demonstrates significant therapeutic potential in preventing ventilator-induced diaphragm dysfunction (VIDD).
• Ang1-7 protects against diaphragm atrophy and contractile dysfunction by mitigating oxidative stress and protease activation.
• These findings support Ang1-7 as a promising strategy to preserve diaphragm function in patients requiring prolonged mechanical ventilation.