Fresh human cardiac tissue for translational research: a novel method of sampling deceased organ donors

Central MessageWe describe novel sampling of fresh human cardiac tissue for use in research from deceased organ donors where the heart was not suitable for transplantation. We describe novel sampling of fresh human cardiac tissue for use in research from deceased organ donors where the heart was not suitable for transplantation. A major barrier to translating basic cardiovascular findings to clinical practice is limited access to fresh human cardiac tissue. The heart is rarely excised, and intraoperative sampling carries life-threatening risk and is resource-intensive. Translational cardiac research is therefore often reliant on animal models, which correlate poorly with human disease.1Zhu Y. Jackson D. Hunter B. Beattie L. Turner L. Hambly B. et al.Models of cardiovascular surgery biobanking to facilitate translational research and precision medicine.ESC Heart Fail. 2022; 9: 21-30Crossref PubMed Scopus (3) Google Scholar Only 30% of deceased organ donors have hearts suitable for organ transplantation,2Transplant Sciety of Australia and New ZealandClinical guidelines for organ transplantation from deceased donors. Version 1.10.https://tsanz.com.au/storage/documents/TSANZ_Clinical_Guidelines_Version-110_Final.pdfDate: 2022Date accessed: April 20, 2023Google Scholar providing an opportunity for donation of the heart for use in research. The Australian Donation and Transplantation Biobank (ADTB) facilitates the donation of tissue samples for use in research using a centralized system integrated into the deceased organ donation program (Reference Transplant Direct paper3Sharma V.J. Starkey G. D'Costa R. James F. Mouhtouris E. Davis L. et al.Australian donation and transplantation Biobank: a research Biobank integrated within a deceased organ and tissue donation program.Transplant Direct. 2023; 9: e1422Crossref PubMed Scopus (3) Google Scholar). We describe the technical aspects of collecting, processing, and storing fresh human cardiac tissue for use in future research as part of ADTB. Ethics approval for ADTB has been described previously.3Sharma V.J. Starkey G. D'Costa R. James F. Mouhtouris E. Davis L. et al.Australian donation and transplantation Biobank: a research Biobank integrated within a deceased organ and tissue donation program.Transplant Direct. 2023; 9: e1422Crossref PubMed Scopus (3) Google Scholar Approval for this project was obtained on June 21, 2021 (HREC/73660/Austin-2021). The donation coordination agency obtains informed consent for donation to the ADTB from the senior available next of kin.3Sharma V.J. Starkey G. D'Costa R. James F. Mouhtouris E. Davis L. et al.Australian donation and transplantation Biobank: a research Biobank integrated within a deceased organ and tissue donation program.Transplant Direct. 2023; 9: e1422Crossref PubMed Scopus (3) Google Scholar If the heart is not suitable for transplantation (Figure 1, A), the heart is excised immediately after all organs for transplantation have been retrieved to minimize heart ischemic time. Access is via a median sternotomy, after which the pericardium is opened and aorta transected in the descending aorta with 2 to 3 cm of the arch vessels. The vena cavae and trachea are ligated, and heart and lungs explanted en-bloc. In cases where lungs are being retrieved for transplantation, unused cardiac tissue is dissected out on the back table. Samples are stored on ice and transported to the laboratory (Figure 1, A). We dissect the coronary arteries, atrium, ventricles, interventricular septum, atrioventricular valves, and semilunar valves as follows.•The specimen is placed under a laminar flow hood, onto an absorbent under pad (Figure 1, B).•The left and right coronary artery systems are excised along the epicardial fat and myocardium (Figure 1, C) along the interventricular atrioventricular grooves (Figure 1, C) to the level of the aorta (Figure 1, D).•The aorta is separated with circumferential dissection along the aortic root (Figure 1, E) with the aortic valve through a 5-mm incision into the left ventricular outflow tract.•The pulmonary artery and pulmonary valve are separated with circumferential dissection via the right ventricular outflow tract (Figure 1, F).•Atrial tissue is obtained by entering the right and left atrial appendages. For the right atrium, the incision is extended to level of the vena cavae (see Figure 1, G).•The right ventricle is opened from the right ventricle 1-cm parallel along the posterior and anterior interventricular septum (Figure 1, H) to obtain samples of the right ventricle (Figure 1, I).•The mitral and tricuspid valves are dissected by further opening the left (Figure 1, J and K) and right (Figure 1, L) ventricles, and excised with their trabecular and papillary muscular attachments.•The previous incisions are continued along their respective atrioventricular septa, partitioning the specimen into independent atria and ventricle chambers (Figure 1, L).•For select projects, samples are further dissected into 1-cm3 blocks and placed into labeled 2-mL screw cap cryovials (Eppendorf tubes) (Figure 1, M). All samples were processed within 90 minutes of arriving at the laboratory. Approximately 100 tissue blocks can be stored per heart (Figure 1, M). For anatomical dissection specimens, tissues are wrapped in 3 layers of aluminium foil and stored in polyethylene boxes in −80 °C freezers with a 24-hour alarm. For laboratory dissection, the tubes are stored by rapid cryopreservation by first submerged in liquid nitrogen (−196 °C) for snap freezing (<5 minutes) and then transferred to −80 °C freezers for long-term storage. Specimens catalogued using Redcap (Research Electronic Data Capture) and FreezerPro (Brooks Life Sciences) databases, labeled with details, including unique ADTB study number, cardiac region, slot number, and box position. We describe a new process to obtain fresh frozen cardiac tissue for use in translational research donated by deceased organ donors, with minimal disruption to clinical workflow and outlay of resources. Between April 2020 and October 2022, 31 hearts were donated to ADTB with a median age of 52 years, with 48% women. Samples have been used for immunohistochemical studies, biochemical analysis, mass spectrometry, cell culture, and novel translational technologies such as spectrophotometric analysis. The preservation of cellular detail, tissue lipids, metabolic features, and proteins makes this approach feasible.4Stock A.T. Parsons S. Sharma V.J. James F. Starkey G. D'Costa R. et al.Intimal macrophages develop from circulating monocytes during vasculitis.Clin Transl Immunology. 2022; 11: e1412Crossref PubMed Scopus (1) Google Scholar,5Stock A.T. Parsons S. D'Silva D.B. Hansen J. Sharma V. James F. et al.Mechanistic target of rapamycin inhibition prevents coronary artery remodeling in a murine model of Kawasaki disease.Arthritis Rheumatol. 2023; 75: 305-317Crossref PubMed Scopus (3) Google Scholar The authors thank the deceased organ donors and their families in providing valuable tissue samples to advance medical research.