NMR Assessment of Me2SO in Decellularized Cryopreserved Aortic Valve Conduits

Lehr, Eric J.; Hermary, Sarah; McKay, Ryan T.; Webb, Deryck N.H.; Abazari, Alireza; McGann, Locksley E.; Coe, James Y.; Korbutt, Gregory S.; Ross, David B.

doi:10.1016/j.jss.2007.03.082

« Previous Next »Journal of Surgical Research
Volume 141, Issue 1 , Pages 60-67, July 2007

NMR Assessment of Me₂SO in Decellularized Cryopreserved Aortic Valve Conduits

Eric J. Lehr, M.D.
- Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
- To whom correspondence and reprint requests should be addressed at Department of Surgery, University of Alberta Hospital, Dvorkin Lounge, 8440 - 112th Street, Edmonton, AB, Canada T6G 2B7.
Sarah Hermary, B.S.
- Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
Ryan T. McKay, Ph.D.
- National High Field NMR Centre, University of Alberta, Edmonton, Alberta, Canada
Deryck N.H. Webb, B.Sc.
- National High Field NMR Centre, University of Alberta, Edmonton, Alberta, Canada
Alireza Abazari, B.S.
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Alberta, Canada
Locksley E. McGann, Ph.D.
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
James Y. Coe, M.D.
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
Gregory S. Korbutt, Ph.D.
- Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
David B. Ross, M.D.
- Department of Surgery, University of Alberta, Edmonton, Alberta, Canada

Received 8 January 2007 published online 21 May 2007.

Introduction

Decellularized cryopreserved allograft vascular tissue may provide a nonimmunogenic scaffold that is suitable for repopulation by cells from a variety of sources, conferring the potential for growth and repair. Although dimethyl sulfoxide (Me₂SO) is generally regarded as a safe cryoprotectant, even low levels may alter function of repopulating cells. We investigated the residual concentration of Me₂SO in the aqueous compartment of cryopreserved ovine aortic valve conduits following decellularization.

Materials and methods

Aortic valve conduits from Suffolk sheep were cryopreserved in 1.1M (7.5% vol/vol) Me₂SO according to the protocol of our local tissue bank. Three aortic valve conduits were decellularized in a series of hypotonic and hypertonic Tris buffers. Tissue samples were taken at regular time intervals throughout the decellularization process and equilibrated in double distilled, deionized H₂O for 28 days. Quantitative proton nuclear magnetic resonance spectroscopy was used to determine the residual Me₂SO concentration in the equilibration solutions from which Me₂SO tissue concentrations were calculated.

Results

After thawing, the mean Me₂SO concentration in the valve conduit was 0.302 ± 0.081 M. The decellularization process resulted in a stepwise reduction in the Me₂SO concentration to less than 8.56 × 10⁻⁵ ± 9 × 10⁻⁵ M (P = 0.02). The diffusion coefficient was 2.5 × 10⁻⁶ cm²/s.

Conclusions

Our study demonstrates that Me₂SO is effectively washed out of the aortic valve conduit during decellularization, resulting in a final concentration that is several orders of magnitude less than Me₂SO concentrations reported to alter cell function.

Key Words: aortic valve allograft, tissue engineering, decellularization, cryopreservation, proton NMR, dimethyl sulfoxide, ovine