Improved vessel preservation after 4 days of cold storage: experimental study in rat arteries

Abstract

Background: Cold storage of arteries for reconstructive and bypass surgery may result in injury of endothelial cells which may promote low perfusion and graft vasculopathy.

Methods: A recently developed N-acetyl histidine-buffered, potassium-chloride enriched, and amino acid-fortified vascular storage solution augmented with iron chelators deferoxamine (100 micromol/L) and LK 614 (20 micromol/L) was studied in the rat superior mesenteric artery and aorta with respect to: (1) potassium-induced vessel tone, (2) endothelium-dependent and -independent relaxation, and (3) endothelial nitric oxide synthase (eNOS) protein expression over 4-days cold storage (4 degrees C).This solution was compared with traditional storage solutions, histidine-tryptophan-ketoglutarate (HTK) and physiological saline solution (PSS).

Results: Vessels stored for 4 days in the new solution were significantly better protected than those stored in traditional HTK or PSS. The protective effects comprised: (1) vessel tone development after stimulation with potassium-chloride solution, (2) endothelium-dependent and -independent vessel relaxation, and (3) eNOS expression. With iron chelators (deferoxamine 100 microM, LK 614 20 microM) present in the storage solution, endothelium-dependent relaxations (eNOS-dependent and K(Ca)-channel-dependent) were fully maintained after 96 hours of cold storage. Endothelial cell structure was significantly better maintained after 96 hours in the new solution than in HTK or PSS solutions. Already, 2 hours of cold storage in HTK resulted in a significant loss of structurally intact endothelium. The structural changes correlated significantly with the diminished vessel relaxation capacity. Furthermore, tissue reductive capacity was only preserved after 96 hours storage if the new solution was used.

Conclusion: The new storage solution is superior to traditional HTK and PSS cold storage with respect to: (1) preservation of vessel structure and function; (2) the presence of iron chelators significantly improved protection of endothelial function; and (3) the new solution permits cold vessel storage for a minimum of 4 days with full maintenance of endothelial function and its coupling to smooth muscle.