Xenotransplantation panel for the detection of infectious agents in pigs.

BACKGROUND: Recent advances in xenotransplantation have produced organs from pigs that are well tolerated in primate models because of genetic changes engineered to delete major antigens from donor animals. To ensure the safety of human transplant recipients, it will be essential to understand both the spectrum of infectious agents in donor pigs and their potential to be transmitted to immunocompromised transplant recipients. Equally important will be the development of new highly sensitive diagnostic methods for use in the detection of these agents in donor animals and for the monitoring of transplant recipients. METHODS: Herein, we report the development of a panel of 30 quantitative polymerase chain reaction (qPCR) assays for infectious agents with the potential to be transmitted to the human host. The reproducibility, sensitivity and specificity of each assay were evaluated and were found to exhibit analytic sensitivity that was similar to that of quantitative assays used to perform viral load testing of human viruses in clinical laboratories. RESULTS: This analytical approach was used to detect nucleic acids of infectious agents present in specimens from 9 sows and 22 piglets derived by caesarean section. The most commonly detected targets in adult animals were Mycoplasma species and two distinct herpesviruses, porcine lymphotrophic herpesvirus 2 and 3. A total of 14 piglets were derived from three sows infected with either or both herpesviruses, yet none tested positive for the viruses indicating that vertical transmission of these viruses is inefficient. CONCLUSIONS: The data presented demonstrate that procedures in place are highly sensitive and can specifically detect nucleic acids from target organisms in the panel, thus ensuring the safety of organs for transplantation as well as the monitoring of patients potentially receiving them.

Assessment of two external telemetry systems (PhysioJacket and JET) in beagle dogs with telemetry implants.

INTRODUCTION: Regulatory guidelines recommend the use of conscious, unrestrained animals for comprehensive cardiovascular safety assessment of a new therapeutic agent. Cardiovascular safety pharmacology studies normally use internal telemetry (surgical implants) in free-moving animals to monitor key ECG endpoints, like the QTc interval, but this technical approach is highly resource intensive. In toxicology studies, ECG recording is also typically performed under chemical or physical restraint, which has a number of disadvantages, e.g., anesthesia confounds, handling stress and limited data collection. External telemetry for ECG recording has the potential to overcome many of these restraint limitations, with the benefit of being a surgically non-invasive method. To evaluate this method, we used two jacket systems: Data Sciences International (DSI) JET and Integrated Telemetry Systems (ITS) PhysioJacket in implanted beagle dogs. METHODS: Heart rate and cardiac intervals were monitored continuously for 22-24 h following oral administration of vehicle (water) or 1 mg/kg E-4031. Data obtained from each jacket system was compared with implant-derived data in the same animal. RESULTS: Significant increases in QT/QTcV (25-30 ms) were noted following treatment with 1 mg/kg E-4031 in both external jacket systems and with implanted telemetry. Throughout the recording periods, the normal variations in heart rate and ECG intervals observed in conscious dogs as detected with the jacket systems, mirrored the changes observed via implant telemetry. DISCUSSION: The overall findings from this study support the use of external telemetry technology as a viable alternative to implants. The data demonstrated that jackets were sufficiently sensitive to detect QT/QTcV changes following E-4031 administration, that were comparable to those derived from implants. As such, this method is an invaluable tool for obtaining high quality ECG data from repeat-dose toxicology studies.