Comparison of arterial storage conditions for delayed arterial ring testing

Area of Science:

• Vascular Biology
• Physiology
• Biomedical Engineering

Background:

• Arterial ring testing is crucial for assessing arterial function, with endothelial dysfunction a key marker in peripheral artery disease (PAD).
• Standardizing ex vivo arterial testing requires optimizing storage conditions to maintain tissue viability and function.
• Previous comparisons of storage conditions have lacked robust validation, particularly in human arteries.

Purpose of the Study:

• To optimize storage conditions for ex vivo arterial segments for endothelial cell (EC) testing using a murine model.
• To evaluate EC function in human PAD arteries under various storage conditions.
• To hypothesize that specific storage protocols will yield superior preservation of arterial function.

Main Methods:

• Murine aortas were stored under various conditions (Opti-MEM at 37°C or 4°C, Krebs-HEPES, Wisconsin solution at 4°C) for 24 hours and compared to immediate testing.
• Vascular function was assessed via isometric force testing, measuring endothelium-dependent and -independent relaxation and arterial contraction.
• Human PAD tibial arteries were tested for relaxation and contraction, analyzing the impact of disturbed vs. stable flow and calcification.

Main Results:

• 4°C WI and 37°C Opti-MEM best preserved endothelium-dependent relaxation and arterial contractility in murine aortas, performing similarly to fresh tissue.
• All tested storage conditions maintained endothelial-independent relaxation and contractility.
• In human PAD arteries, disturbed flow significantly reduced relaxation (2% vs. 59%), while calcification had no significant impact. Arterial contractility was measurable in more samples than relaxation.

Conclusions:

• 24-hour storage in 4°C WI or 37°C Opti-MEM effectively preserves key arterial functions in murine models.
• In human PAD arteries, disturbed pre-harvest flow conditions impair ex vivo endothelial-dependent relaxation, highlighting the persistence of EC dysfunction.
• Arterial contractility is more reliably preserved than relaxation in human PAD samples, and flow conditions, not calcification, influence relaxation outcomes.