Life-supporting function of genetically modified swine lungs in baboons.
OBJECTIVE
During ex vivo perfusion with human blood, homozygous galactosyl transferase knockout swine lungs exhibit prolonged survival (approximately 2 hours) relative to wild-type (<15 minutes) and swine lungs expressing human decay accelerating factor (<1 hour). In this study, the in vivo behavior of galactosyl transferase knockout lungs was evaluated.


METHODS
Three galactosyl transferase knockout swine left lungs were transplanted into baboons in a life-supporting model. One baboon lung allograft and two swine lung xenografts transgenic for human membrane cofactor protein (CD46) served as controls.


RESULTS
Whereas two membrane cofactor protein lungs exhibited high pulmonary vascular resistance (>500 mm Hg x min/L) and failed to support life within 21 minutes, two of three galactosyl transferase knockout lungs supported life, for 90 and 215 minutes, and displayed low peripheral vascular resistance (48 +/- 12 mm Hg x min/L at 60 minutes), similar to the allogeneic control. Complement activation (delta C3a < 250 ng/mL through 60 minutes) and C5b-9 deposition were minimal in both galactosyl transferase knockout and membrane cofactor protein lungs. Neutrophils, monocytes, and platelets were rapidly sequestered in galactosyl transferase knockout and human membrane cofactor protein lung recipients, unlike the allogeneic control (<20%); and thrombin formation (delta plasma fraction 1+2 > 0.5 nmol/L) was seen in the galactosyl transferase knockout recipients. Platelet activation (beta-thromboglobulin rise > 200) and appearance of capillary congestion and vessel thrombosis confirmed coagulation activation associated with galactosyl transferase knockout lung failure.


CONCLUSIONS
Galactosyl transferase knockout swine lungs are significantly protected in vivo from the physiologic consequences (increased pulmonary vascular resistance, capillary leak) associated with hyperacute lung rejection. As during ex vivo perfusion, dysregulated coagulation-thrombin elaboration, platelet activation, and intravascular thrombosis-mediates galactosyl transferase knockout lung xenograft injury.
Nguyen
Bao-Ngoc H
BN
University of Maryland and Baltimore Veterans Administration Medical Center, Baltimore, USA.
Azimzadeh
Agnes M
AM
Zhang
Tianshu
T
Wu
Guosheng
G
Schuurman
Henk-Jan
HJ
Shuurman
Henk-Jan
HJ
Sachs
David H
DH
Ayares
David
D
Allan
James S
JS
Pierson
Richard N
RN
D000818:Animals; D001772:Blood Cell Count; D003167:Complement Activation; D015926:Complement C3a / Q000032:analysis; D005700:Galactosyltransferases / Q000235:genetics; D006085:Graft Survival; D007155:Immunologic Factors; D008168:Lung / Q000473:pathology; D016040:Lung Transplantation; D051916:Membrane Cofactor Protein / Q000378:metabolism; D030781:Organisms, Genetically Modified; D048530:Papio anubis; D010446:Peptide Fragments / Q000097:blood; D015539:Platelet Activation; D011516:Prothrombin; D011652:Pulmonary Circulation; D013552:Swine; D014183:Transplantation, Heterologous; D014655:Vascular Resistance; D001620:beta-Thromboglobulin / Q000032:analysis*
D007155:Immunologic Factors; D051916:Membrane Cofactor Protein; D010446:Peptide Fragments; D001620:beta-Thromboglobulin; C045879:prothrombin fragment 1.2; D015926:Complement C3a; D011516:Prothrombin; D005700:Galactosyltransferases