Monitoring pig-to-primate cardiac xenografts with live Internet images of recipients and xenograft telemetric signals: histologic and immunohistochemical correlations.
BACKGROUND
Monitoring pig-to-primate cardiac xenografts is often difficult in awake and uncooperative primates. We investigated the possibility of monitoring xenotransplantation through Internet broadcasting of (1) continuous video images of transplant recipients and (2) xenograft telemetric signals detected by an implanted device. The telemetric readings were later compared with histology and immunohistochemistry for signs of rejection.


METHODS
Heterotopic baboon-to-baboon (n = 2) and transgenic pig (human complement regulatory proteins CD59/DAF, n = 3; MCP, n = 1)-to-baboon transplants were performed with serial biopsies for hematoxylin-and-eosin staining and immunohistochemical detection of immunoglobulin M (IgM) and complement membrane attack complex (MAC) deposition. Baboon recipients were continuously monitored with a QuickCamPro digital camera, whereas grafts were monitored with a Data Science International implantable telemetric system. Video images and telemetric signals were broadcast over the Internet through a laptop computer.


RESULTS
Baboon allografts remained healthy until explant on Day 14, whereas pig xenografts were rejected on Day 5, 6, 7, and 11. Telemetry of allografts and xenografts documented regular rhythm with an average heart rate of 80 to 120, but xenografts developed bradycardia and widened/dampened QRS complexes 24 to 48 hours before graft loss. Continuous video monitoring of recipient activities was vital in differentiating between graft arrhythmias and telemetric artifacts. Allograft biopsies showed little cellular infiltrate, whereas xenograft biopsies showed increasing IgM and MAC deposition, with extensive thrombi and myocardial damage 24 hours before cessation of cardiac activities.


CONCLUSIONS
Combined video surveillance of recipient activities and graft telemetric signals is a useful method to continuously monitor abdominal cardiac grafts in large, uncooperative, awake primates. QRS-complex widening associated with progressive bradycardia correlated with histologic and immunohistochemical evidence of xenograft rejection.
Chen
R H
RH
Division of Cardiac Surgery, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Kadner
A
A
Adams
D H
DH
D000818:Animals; D001706:Biopsy; D015938:Complement Membrane Attack Complex / Q000276:immunology / Q000378:metabolism*; D004562:Electrocardiography; D006084:Graft Rejection / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D006085:Graft Survival; D016027:Heart Transplantation / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D007075:Immunoglobulin M / Q000276:immunology / Q000378:metabolism*; D020407:Internet; D010215:Papio; D013552:Swine; D013686:Telemetry / Q000379:methods*; D014183:Transplantation, Heterologous; D014741:Video Recording
D015938:Complement Membrane Attack Complex; D007075:Immunoglobulin M