Monitoring the Health of Ex Vivo Perfused Organs for Transplantation Using New Tools in Raman Spectroscopy

Raman spectroscopy was applied in this research to monitor the overall health and degradation of porcine livers, hearts, and kidneys when perfused ex vivo for transplantation using the VasoWave^TM perfusion system.  A novel Raman-based diagnostic analysis procedure was developed in this research that generates information about organ health in real-time using analytical methods that are non-destructive and label-free.  The data analysis is accomplished using a multivariate statistical approach involving Raman spectral reduction using principal component analysis and linear discriminant analysis.  These tools have been encoded along with necessary routines for large-scale spectral dataset normalization into a custom MATLAB toolbox and stand-alone application with an intuitive graphical user interface. In the analyses of ex vivo perfused livers it was found that degradation from a “healthy” initial state during perfusion over 24 hours could be tracked in real-time by Raman analysis of the perfusate fluid and multivariate statistical analysis of the resulting spectra.  Significant influences of the perfusion handles of temperature and pressure (systolic and diastolic) were revealed, with pressure proving to have greater influence for preservation of the livers tested.  Raman analysis of static cold storage hearts revealed differences in degradation properties among the left and right atrial and ventricular chambers.  Analyses of ex vivo kidney perfusions by Raman spectroscopy have also revealed several key parameters that are critical for extending the useful life of an organ for successful transplantation.  These will be discussed in detail in this presentation.