Time dependent changes in aortic tissue during cold storage in physiological solution

Background: Stored vascular tissues are employed in biomedical research for studies in imaging, in biomechanics, and/or in assessing vessel diseases. In the present study, the stability of aortic tissue in phosphate buffer saline (PBS) at 4 °C was monitored over a course of 10 days as determined by the rate of glucose permeation measured by optical coherence tomography (OCT) and validated by histology. Methods and results: The initial mean permeability through fresh porcine aorta was (2.32 ± 0.46) × 10^{- 5} cm/s (n = 5); after maintaining the tissue at 4 °C for 10 days, the mean rate was (7.37 ± 0.41) × 10^{- 5} cm/s (n = 4), an increase of nearly 300%. A z-test verified that a significant change in the permeability rate (p < 0.05) had occurred after 4 days of 4 °C storage. Histology was used to quantify changes in tissue pore area. The increase in average pore area paralleled the increase in permeability rate over 10 days. Conclusions: These results suggest that (1) the structural integrity of aortic tissue at 4 °C is retained for at least the first three days after resection and (2) OCT is a powerful technology well suited for evaluating tissue structural integrity over time. General significance: Functional OCT imaging provides for a noninvasive and quantitative technique in determining the structural integrity of aortic tissue stored at 4 °C. This modality may be used for assessing the efficacy of other preservation techniques.