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Study Objective: The aim of the study was to develop a quantifiable assay for the assessment of cellular viability in cardiovascular tissue., Design: Radiolabelled proline and inulin were used to assess metabolic viability of the cellular component of cuspal tissue from porcine heart valves., Experimental Materials: Pig hearts were removed within 20 min of death and transported on ice in tissue culture medium. Cuspal tissues were dissected rapidly and held on ice in physiological medium until assayed., Main Results: Radiolabelled inulin was shown to be a useful marker for determining the amount of radiolabelled proline present in the extracellular tissue volume, permitting calculation of the amount of radiolabelled proline accumulated by the cellular component. Proline accumulation by the cellular component was affected by concentration of proline, time allowed for proline accumulation, in vitro cold ischaemia, and metabolic poisons. Based on mg tissue protein, proline and inulin accumulations were equivalent for aortic, pulmonary, mitral, and tricuspid valve tissues, suggesting that these valve tissues may be used interchangeably in assessment of metabolic viability of cellular components of cardiovascular tissue., Conclusion: Radiolabelled proline and inulin transport assays allow a quantitative estimate of total cellular viability.

The purpose of this study was to find an antibiotic disinfecting solution for cardiovascular tissues which would allow maximal cellular viability while maintaining antibacterial and antifungal activity. Cellular viability of porcine heat valves sterilised using antibiotics was assessed by radiolabelled proline transport assays. The results show that storage of valve tissues in RPMI 1640 tissue culture medium (4 degrees C) alone decreases the cellular viability by 50%, 60% and 90% within 12, 24, and 72 h, respectively. Amphotericin B was shown to be the toxic component of the antibiotic sterilising solution recommended by Strickett and coworkers, accounting for all the observed antibiotic toxicity. It reduced the cellular viability by 100% within 12 h of storage at 4 degrees C. Our study also showed that streptomycin is responsible for the loss of cellular viability in the antibiotic medium utilised by O'Brien's group. The results show that after storage of valve tissues for 12 h in O'Brien's antibiotic solution, the cellular viability was reduced by 60%, and after 24 h by 90%. Cefoxitin, lincomycin, polymyxin B, vancomycin and penicillin had no apparent effects on viability of cells in the cardiovascular tissues utilised in this study. In conclusion, heart valve tissue may be sterilised effectively using selective antibiotics without causing significant damage to cellular viability.