Mitochondrial Functional Capacity Is Impaired in Angiotensin II-Infused Mice and Not Recovered by Metformin

Area of Science:

• Cardiovascular Biology
• Mitochondrial Medicine
• Vascular Pathophysiology

Background:

• Pathophysiological mechanisms of Abdominal Aortic Aneurysm (AAA) remain unclear.
• Mitochondrial dysfunction, specifically reduced oxidative phosphorylation (OXPHOS), is implicated in vascular smooth muscle cells.
• Metformin's protective effects on AAA are known, but the underlying mechanisms are not fully understood.

Purpose of the Study:

• To establish a method for measuring ex vivo mitochondrial functional capacity in intact murine AAA tissue.
• To confirm impaired OXPHOS in AAA.
• To investigate if metformin's protective effect against AAA is mediated by mitochondrial function.

Main Methods:

• AAA was induced in ApoE KO mice using AngII infusion.
• Metformin was administered via drinking water.
• Mitochondrial functional capacity was assessed ex vivo in permeabilized aortic tissue using high-resolution respirometry.

Main Results:

• Mitochondrial respiration was successfully measured in whole aneurysmal tissue.
• AngII-induced AAA showed impaired mitochondrial function, with decreased Complex I and Complex II oxygen consumption.
• Metformin treatment did not restore mitochondrial function in AAA mice.

Conclusions:

• Mitochondrial function can be assessed in murine AAA tissue, offering a physiological study approach.
• AAA is characterized by impaired mitochondrial function.
• Metformin's prevention of AAA does not appear to be mediated by restoring mitochondrial function.