A Study on an Effective Decellularization Technique for a Xenograft Cardiac Valve: the Effect of Osmotic Treatment with Hypotonic Solution

Sung, Si Chan; Kim, Yong Jin; Choi, Sun Young; Park, Ji Eun; Kim, Kyung Hwan; Kim, Woong Han

Abstract

BACKGROUND: Cellular remnants in the bioprosthetic heart valve are known to be related to a host's immunologic response and they can form the nidus for calcification. The extracellular matrix of the decellularized valve tissue can also be used as a biological scaffold for cell attachment, endothelialization and tissue reconstitution. Thus, decellularization is the most important part in making a bioprosthetic valve and biological scaffold. Many protocols and agents have been suggested for decellularization, yet there have been few reports about the effect of a treatment with hypotonic solution prior to chemical or enzymatic treatment. This study investigated the effect of a treatment with hypotonic solution and the appropriate environments such as temperature, the treatment duration and the concentration of sodium dodecylsulfate (SDS) for achieving proper decellularization. MATERIAL AND METHOD: Porcine aortic valves were decellularized with sodium dodecylsulfate at various concentrations (0.25%, 0.5%), time durations (6, 12, 24 hours) and temperatures (4degrees C, 20degrees C)(Group B). Same the number of porcine aortic valves (group A) was treated with hypotonic solution prior to SDS treatment at the same conditions. The duration of exposure to the hypotonic solution was 4, 7 and 14 hours and the temperature was 4degrees C and 20degrees C, respectively. The degree of decellularization was analyzed by performing hematoxylin and eosin staining. RESULT: There were no differences in the degree of decellularization between the two concentrations (0.25% 0.5%) of SDS. Twenty four hours treatment with SDS revealed the best decellularization effect for both groups A and B at the temperature of 4degrees C, but there was no differences between the groups at 20degrees C. Treatment with hypotonic solution (group A) showed a better decellularization effect at all the matched conditions. Fourteen hours treatment at 4degrees C with hypotonic solution prior to SDS treatment revealed the best decellularization effect. The treatment with hypotonic solution at 20degrees C revealed a good decellularization effect, but this showed significant extracellular matrix destruction. CONCLUSION: The exposure of porcine heart valves to hypotonic solution prior to SDS treatment is highly effective for achieving decellularization. Osmotic treatment with hypotonic solution should be considered for achieving decellularization of porcine aortic valves. Further study should be carried out to see whether the treatment with hypotonic solution could reduce the exposure duration and concentration of chemical detergents, and also to evaluate how the structure of the extracellular matrix of the porcine valve is affected by the exposure to hypotonic solution.