Porcine kidney xenotransplantation: From primate models to clinical reality

Abstract

The escalating global incidence of end-stage renal disease has exacerbated the critical shortage of kidneys from human donors. Porcine kidney xenotransplantation has emerged as the most promising alternative solution to providing an unlimited organ supply. In this review, we examine the historical evolution, current breakthroughs and future directions of kidney xenotransplantation. We probe the milestones from early attempts and non-human primate (NHP) experiments to recent clinical trials involving both brain-dead and living human recipients. The core of this review provides an in-depth discussion of the significant barriers in kidney xenotransplantation, including immune rejection, physiological incompatibilities and the risk of cross-species infection. Next, we systematically outline the multifaceted strategies developed to overcome these barriers. The rapid development of gene editing technology has enabled the establishment of multigene-edited pigs. These donors feature knockout of key carbohydrate antigen genes and expression of various human proteins, including complement regulators, anticoagulants, and immunomodulators. These genetic modifications have extended xenograft survival in NHP models to over 750 days. This is synergized with novel immunosuppressive regimens, tolerance-induction protocols, cellular therapies, and emerging adjuncts like bioengineering materials and organoid-on-a-chip technologies. Finally, we discuss future directions, raising concerns about potential complications arising from the biomechanical incompatibility between pigs and human in xenotransplantation, highlighting the need to deploy advanced multi-omics to identify unknown xenoantigens, optimize bioengineering materials for local immunomodulation, and validate extracellular vesicles as non-invasive biomarkers. While challenges for long-term xenograft survival remain, kidney xenotransplantation is rapidly advancing from preclinical research to clinical reality, holding huge potential to resolve the organ shortage crisis.

Keywords

genetically engineered pigs / immune rejection / immunosuppression / kidney xenotransplantation

References

[1] Valentin JF, Lebranchu Y, Nivet H. Can man live with a pig kidney? Nephrologie. 1999; 20: 189-195.

[2] Kirkman RL. Of swine and men: organ physiology in different species. In: MA Hardy, ed. Xenograft 25. Elsevier; 1989: 125-134.

[3] Hirano I, Suzuki N. The neural crest as the first production site of the erythroid growth factor erythropoietin. Front Cell Dev Biol. 2019; 7:105.

[4] Hansen-Estruch C, Bikhet MH, Javed M, et al. Renin-angiotensin-aldosterone system function in the pig-to-baboon kidney xenotransplantation model. Am J Transplant. 2023; 23: 353-365.

[5] Zhao H, Zheng S, Fan J, et al. New chapter in reform and development of organ donation and transplantation in China: embracing past, grounding in national conditions, upholding steadfast belief, and looking forward to future. Hepatobiliary Pancreat Dis Int. 2025; 24: 6-13.

[6] Christie R, Curie A, Chris C, et al. Organ donation and transplantation registries across the globe: a review of the current state. Transplantation. 2024; 108: e321-e326.

[7] Hryhorowicz M, Zeyland J, Słomski R, Lipiński D. Genetically modified pigs as organ donors for xenotransplantation. Mol Biotechnol. 2017; 59: 435-444.

[8] Montgomery RA, Mehta SA, Parent B, Griesemer A. Next steps for the xenotransplantation of pig organs into humans. Nat Med. 2022; 28: 1533-1536.

[9] Wijkstrom M, Iwase H, Paris W, Hara H, Ezzelarab M, Cooper DK. Renal xenotransplantation: experimental progress and clinical prospects. Kidney Int. 2017; 91: 790-796.

[10] Alexandre L, Valentin G, Alessia G, et al. Immune response after pig-to-human kidney xenotransplantation: a multimodal phenotyping study. Lancet. 2023; 402: 1158-1169.

[11] Zuhaib I, Jamie B, Michel A, Robert W, Kevin W, Cooper DK. Selected physiologic compatibilities and incompatibilities between human and porcine organ systems. Xenotransplantation. 2006; 13: 488-499.

[12] Al-Shehabi H, Fiebig U, Kutzner J, et al. Human SAMHD1 restricts the xenotransplantation relevant porcine endogenous retrovirus (PERV) in non-dividing cells. J Gen Virol. 2019; 100: 656-661.

[13] Längin M, Mayr T, Reichart B, et al. Consistent success in life-supporting porcine cardiac xenotransplantation. Nature. 2018; 564: 430-433.

[14] Anand RP, Layer JV, Heja D, et al. Design and testing of a humanized porcine donor for xenotransplantation. Nature. 2023; 622: 393-401.

[15] Luo J, Bian C, Liu M, et al. Research on gene editing and immunosuppressants in kidney xenotransplantation. Transpl Immunol. 2025; 89:102184.

[16] Makoto T, Jane MO, Kaitlan A, et al. Cardiac allograft tolerance can be achieved in nonhuman primates by donor bone marrow and kidney cotransplantation. Sci Transl Med. 2025; 17:eads0255.

[17] Yamada K, Yazawa K, Shimizu A, et al. Marked prolongation of porcine renal xenograft survival in baboons through the use of α1,3-galactosyltransferase knockout donors and the cotransplantation of vascularized thymic tissue. Nat Med. 2005; 11: 32-34.

[18] Wang A, Ribeiro R, Ali A, et al. Ex vivo enzymatic treatment converts blood type a donor lungs into universal blood type lungs. Sci Transl Med. 2022; 14:eabm7190.

[19] Lin J, Liu S, Xue X, et al. Injectable genetic engineering hydrogel for promoting spatial tolerance of transplanted kidney in situ. Adv Sci Weinh. 2024; 11:e2408631.

[20] Corredera IG, Amato G, Moya-Rull D, Garreta E, Montserrat N. Unlocking the full potential of human pluripotent stem cell-derived kidney organoids through bioengineering. Kidney Int. 2025; 108: 38-47.

[21] Prashanth V, Laxminarayana K, Andreas H, et al. Tissue-specific exosome biomarkers for noninvasively monitoring immunologic rejection of transplanted tissue. J Clin Invest. 2017; 127: 1375-1391.

[22] Cui M, Wang Y, Wang J. Research progress of extracellular vesicles as biomarkers in organ transplantation. Adv Clin Med. 2024; 14: 1390-1395.

[23] Chen S. Exploring pathways of clinical allografting of renal transplantation. Chin J Organ Transplant. 2022; 43: 641-646.

[24] Paul IT. History of Transplantation: Thirty-Five Recollections. UCLA Immunogenetics Cente; 1991.

[25] Daniel R, Daniel JH. Mathieu Jaboulay's (1860–1913) contribution to xenotransplantation. Xenotransplantation. 2022; 29:e12765.

[26] David H, Clyde FB, Thomas ES. A History of Organ Transplantation: Ancient Legends to Modern Practice. University of Pittsburgh Press; 2012.

[27] Morel L, Papin E. Les applications physiologiques et chirurgicales des transplantations renales [The physiological and surgical applications of kidney transplantations]. Biol Med. 1913; 11: 397.

[28] Neuhof H. The Transplantation of Tissues. Appelton; 1923.

[29] Barry JM, Murray JE. The first human renal transplants. J Urol. 2006; 176(3): 888-890.

[30] Hitchcock CR, Kiser JC, Telander RL, Seljeskog EL. Baboon renal grafts. JAMA. 1964; 189: 934.

[31] Reemtsma K, McCracken BH, Schlegel JU, et al. Renal Heterotransplantation in man. Ann Surg. 1964; 160: 384-410.

[32] Reemtsma K. Address by the honorary founding president of the xenotransplantation society. The eye of an eagle: xenobiology and the quest for bioadvantage. Xenotransplantation. 2000; 7: 80-82.

[33] Starzl TE, Marchino TL, Peters GN, et al. Renal heterotransplantation from baboon-to-man: experience with six cases. Transplantation. 1964; 2: 752.

[34] Hume DM. Discussion of Reemtsma paper. Ann Surg. 1964; 160: 409.

[35] Traeger J, Fries D, Perrin J. Heterotransplantation chez l'homme. Premier resultats [Heterotransplantation in Man. First Results]. Vol 214. Proceedings of the European Dialysis and Transplant Association; 1965.

[36] Cortesini R, Casciani C, Cucchiara G. Heterotransplantation in primates: current state of affairs. In: H Balner, ed. Infection and Immunosuppression in Subhuman Primates. Munksgaard; 1969: 239.

[37] Huff JL, Barry PA. B-virus (cercopithecine herpesvirus 1) infection in humans and macaques: potential for zoonotic disease. Emerg Infect Dis. 2003; 9(2): 246-250.

[38] Cooper DKC, Hara H, Iwase H, et al. Clinical pig kidney xenotransplantation: how close are we? J Am Soc Nephrol. 2020; 31: 12-21.

[39] Lu T, Yang B, Wang R, Qin C. Xenotransplantation: current status in preclinical research. Front Immunol. 2020; 10:3060.

[40] Li Q, Shaikh S, Iwase H, et al. Carbohydrate antigen expression and anti-pig antibodies in new world capuchin monkeys: relevance to studies of xenotransplantation. Xenotransplantation. 2019; 26:e12498.

[41] Kim SC, Mathews DV, Breeden CP, et al. Long-term survival of pig-to-rhesus macaque renal xenografts is dependent on CD4 T cell depletion. Am J Transplant. 2019; 19: 2174-2185.

[42] Robson SC, Am Esch JS, Bach FH. Factors in xenograft rejection. Ann N Y Acad Sci. 1999; 875: 261-276.

[43] Galili U, Shohet SB, Kobrin E, Stults CL, Macher BA. Man, apes, and old world monkeys differ from other mammals in the expression of α-galactosyl epitopes on nucleated cells. J Biol Chem. 1988; 263: 17755-17762.

[44] Bouhours D, Pourcel C, Bouhours J-F. Simultaneous expression by porcine aorta endothelial cells of glycosphingolipids bearing the major epitope for human xenoreactive antibodies (Galα1-3Gal), blood group H determinant and N-glycolylneuraminic acid. Glycoconj J. 1996; 13: 947-953.

[45] Byrne GW, Stalboerger PG, Du Z, Davis TR, McGregor CGA. Identification of new carbohydrate and membrane protein antigens in cardiac xenotransplantation. Transplantation. 2011; 91: 287-292.

[46] Shaper NL, Lin SP, Joziasse DH, Kim DY, Yang-Feng TL. Assignment of two human alpha-1,3-galactosyltransferase gene sequences (GGTA1 and GGTA1P) to chromosomes 9q33-q34 and 12q14-q15. Genomics. 1992; 12: 613-615.

[47] Irie A, Koyama S, Kozutsumi Y, Kawasaki T, Suzuki A. The molecular basis for the absence of N-glycolylneuraminic acid in humans. J Biol Chem. 1998; 273: 15866-15871.

[48] Galili U, Rachmilewitz EA, Peleg A, Flechner I. A unique natural human IgG antibody with anti-alpha-galactosyl specificity. J Exp Med. 1984; 160: 1519-1531.

[49] Kappler K, Hennet T. Emergence and significance of carbohydrate-specific antibodies. Genes Immun. 2020; 21: 224-239.

[50] Montiel M-D, Krzewinski-Recchi M-A, Delannoy P, Harduin-Lepers A. Molecular cloning, gene organization and expression of the human UDP-GalNAc:Neu5Acalpha2-3Galbeta-R beta1,4-N-acetylgalactosaminyltransferase responsible for the biosynthesis of the blood group Sda/cad antigen: evidence for an unusual extended cytoplasmic domain. Biochem J. 2003; 373: 369-379.

[51] Stenfelt L, Hellberg Å, Möller M, Thornton N, Larson G, Olsson ML. Missense mutations in the C-terminal portion of the B4GALNT2-encoded glycosyltransferase underlying the Sd(a-) phenotype. Biochem Biophys Rep. 2019; 19:100659.

[52] Renton PH, Howell P, Ikin EW, Giles CM, Goldsmith KLG. Anti-Sda, a new blood group antibody. Vox Sang. 1967; 13: 493-501.

[53] Ma D, Hirose T, Lassiter G, et al. Kidney transplantation from triple-knockout pigs expressing multiple human proteins in cynomolgus macaques. Am J Transplant. 2022; 22: 46-57.

[54] Java A, Bresin E. Post-transplant thrombotic microangiopathy. J Am Soc Nephrol. 2025; 36: 940-951.

[55] Maeda A, Kogata S, Toyama C, et al. The innate cellular immune response in xenotransplantation. Front Immunol. 2022; 13:858604.

[56] Puga Yung G, Schneider MKJ, Seebach JD. The role of NK cells in pig-to-human xenotransplantation. J Immunol Res. 2017; 2017:4627384.

[57] Shah JA, Lanaspa MA, Tanabe T, Watanabe H, Johnson RJ, Yamada K. Remaining physiological barriers in porcine kidney xenotransplantation: potential pathways behind proteinuria as well as factors related to growth discrepancies following pig-to-kidney xenotransplantation. J Immunol Res. 2018; 2018:6413012.

[58] Yamada K, Ariyoshi Y, Pomposelli T, Sekijima M. Co-transplantation of vascularized thymic graft with kidney in pig-to-nonhuman primates for the induction of tolerance across xenogeneic barriers. Methods Mol Biol. 2020; 2110: 151-171.

[59] Hammer C. Evolution. Its complexity and impact on xenotransplantation. In: DKC Cooper, E Kemp, JL Platt, DJG White, eds. Xenotransplantation. 2nd ed. Springer; 1996: 716.

[60] Cooper DKC. Porcine red blood cells as a source of blood transfusion in humans. Xenotransplantation. 2003; 10: 384-386.

[61] Mohan Rao LV, Esmon CT, Pendurthi UR. Endothelial cell protein C receptor: a multiliganded and multifunctional receptor. Blood. 2014; 124: 1553-1562.

[62] Esmon C. Do-all receptor takes on coagulation, inflammation. Nat Med. 2005; 11: 475-477.

[63] Thein E, Hammer C. Physiologic barriers to xenotransplantation. Curr Opin Organ Transplant. 2004; 9: 186-189.

[64] Hackenthal E, Paul M, Ganten D, Taugner R. Morphology, physiology, and molecular biology of renin secretion. Physiol Rev. 1990; 70: 1067-1116.

[65] Sen S, Hirawawa K, Smeby RR, Bumpus FM. Measurement of plasma renin substrate using homologous and heterologous renin. Am J Phys. 1971; 221: 1476-1480.

[66] Wang W, Liang TC. Substrate specificity of porcine renin: P1', P1, and P3 residues of renin substrates are crucial for activity. Biochemistry. 1994; 33: 14636-14641.

[67] Soin B, Smith KG, Zaidi A, et al. Physiological aspects of pig-to-primate renal xenotransplantation. Kidney Int. 2001; 60: 1592-1597.

[68] Firl DJ, Lassiter G, Hirose T, et al. Clinical and molecular correlation defines activity of physiological pathways in life-sustaining kidney xenotransplantation. Nat Commun. 2023; 14:3022.

[69] Miltenyi M. Urinary protein excretion in healthy children. Clin Nephrol. 1979; 12: 216-220.

[70] Oda M, Satta Y, Takenaka O, Takahata N. Loss of urate oxidase activity in hominoids and its evolutionary implications. Mol Biol Evol. 2002; 19: 640-646.

[71] Simmonds HA, Hatfield PJ, Cameron JS, Cadenhead A. Uric acid excretion by the pig kidney. Am J Phys. 1976; 230: 1654-1658.

[72] Wen D, Boissel JP, Tracy TE, et al. Erythropoietin structure-function relationships: high degree of sequence homology among mammals. Blood. 1993; 82: 1507-1513.

[73] Iwase H, Klein EC, Cooper DKC. Physiologic aspects of pig kidney transplantation in nonhuman primates. Comp Med. 2018; 68: 332-340.

[74] David RB, Blom AK, Sjaastad OV, et al. The porcine erythropoietin gene: cDNA sequence, genomic sequence and expression analysis in piglets. Domest Anim Endocrinol. 2001; 20: 137-147.

[75] Horwitz JK, Bin S, Fairchild RL, et al. Linking erythropoietin to Treg-dependent allograft survival through myeloid cells. JCI Insight. 2022; 7:e158856.

[76] Donadei C, Angeletti A, Cantarelli C, et al. Erythropoietin inhibits SGK1-dependent Th17 induction and Th17-dependent kidney disease. JCI Insight. 2019; 5:e127428.

[77] Tsujita M, Kosugi T, Goto N, et al. The effect of maintaining high hemoglobin levels on long-term kidney function in kidney transplant recipients: a randomized controlled trial. Nephrol Dial Transplant. 2019; 34: 1409-1416.

[78] Schechter A, Gafter-Gvili A, Shepshelovich D, et al. Post renal transplant anemia: severity, causes and their association with graft and patient survival. BMC Nephrol. 2019; 20: 51.

[79] Denner J. The porcine cytomegalovirus (PCMV) will not stop xenotransplantation. Xenotransplantation. 2022; 29:e12763.

[80] Ulrich S, Goltz M, Ehlers B. Characterization of the DNA polymerase loci of the novel porcine lymphotropic herpesviruses 1 and 2 in domestic and feral pigs. J Gen Virol. 1999; 80: 3199-3205.

[81] Denner J. Why was PERV not transmitted during preclinical and clinical xenotransplantation trials and after inoculation of animals? Retrovirology. 2018; 15: 28.

[82] Ma Y, Jia J, Fan R, et al. Screening and identification of the first non-CRISPR/Cas9-treated Chinese miniature pig with defective porcine endogenous retrovirus pol genes. Front Immunol. 2022; 12:797608.

[83] Puga Yung GP, Schneider MK, Seebach JD. Immune responses to alpha1,3 galactosyltransferase knockout pigs. Curr Opin Organ Transplant. 2009; 14: 154-160.

[84] Byrne GW, du Z, Stalboerger P, Kogelberg H, McGregor CGA. Cloning and expression of porcine β1,4 N-acetylgalactosaminyl transferase encoding a new xenoreactive antigen. Xenotransplantation. 2014; 21: 543-554.

[85] Perota A, Galli C. N-glycolylneuraminic acid (Neu5Gc) null large animals by targeting the CMP-Neu5Gc hydroxylase (CMAH). Front Immunol. 2019; 10:2396.

[86] Martínez-Alarcón L, Liarte S, Quereda JJ, et al. Profiling human CD55 transgene performance assist in selecting best suited specimens and tissues for swine organ xenotransplantation. Biology. 2021; 10:100659.

[87] Bongoni AK, Kiermeir D, Schnider J, et al. Transgenic expression of human CD46 on porcine endothelium: effect on coagulation and fibrinolytic cascades during ex vivo human-to-pig limb xenoperfusions. Transplantation. 2015; 99: 2061-2069.

[88] Salvaris EJ, Moran CJ, Roussel JC, Fisicaro N, Robson SC, Cowan PJ. Pig endothelial protein C receptor is functionally compatible with the human protein C pathway. Xenotransplantation. 2020; 27:e12557.

[89] Tena A, Kurtz J, Leonard DA, et al. Transgenic expression of human CD47 markedly increases engraftment in a murine model of pig-to-human hematopoietic cell transplantation. Am J Transplant. 2014; 14: 2713-2722.

[90] Balla G, Jacob HS, Balla J, et al. Ferritin: a cytoprotective antioxidant strategem of endothelium. J Biol Chem. 1992; 267: 18148-18153.

[91] Baldan N, Rigotti P, Calabrese F, et al. Ureteral stenosis in HDAF pig-to-primate renal xenotransplantation: a phenomenon related to immunological events? Am J Transplant. 2004; 4: 475-481.

[92] Iwase H, Liu H, Wijkstrom M, et al. Pig kidney graft survival in a baboon for 136 days: longest life-supporting organ graft survival to date. Xenotransplantation. 2015; 22: 302-309.

[93] Iwase H, Hara H, Ezzelarab M, et al. Immunological and physiological observations in baboons with life-supporting genetically engineered pig kidney grafts. Xenotransplantation. 2017; 24:e12293.

[94] Loss M, Kunz R, Przemeck M, et al. Influence of cold ischemia time, pretransplant anti-porcine antibodies, and donor/recipient size matching on hyperacute graft rejection after discordant porcine to cynomolgus kidney transplantation. Transplantation. 2000; 69: 1155-1159.

[95] Yu XH, Deng WY, Jiang HT, Li T, Wang Y. Kidney xenotransplantation: recent progress in preclinical research. Clin Chim Acta. 2021; 514: 15-23.

[96] McCurry KR, Kooyman DL, Alvarado CG, et al. Human complement regulatory proteins protect swine-to-primate cardiac xenografts from humoral injury. Nat Med. 1995; 1: 423-427.

[97] Bühler L, Yamada K, Kitamura H, et al. Pig kidney transplantation in baboons: anti-gal(alpha)1-3Gal IgM alone is associated with acute humoral xenograft rejection and disseminated intravascular coagulation. Transplantation. 2001; 72: 1743-1752.

[98] Firl DJ, Markmann JF. Measuring success in pig to non-human-primate renal xenotransplantation: systematic review and comparative outcomes analysis of 1051 life-sustaining NHP renal allo- and xeno-transplants. Am J Transplant. 2022; 22(6): 1527-1536.

[99] Ashton-Chess J, Roussel J, Bernard P, et al. The effect of immunoglobulin immunadsorptions on delayed xenograft rejection of human CD55 transgenic pig kidneys in baboons. Xenotransplantation. 2003; 10: 552-561.

[100] Ashton-Chess J, Meurette G, Karam G, et al. The study of mitoxantrone as a potential immunosuppressor in transgenic pig renal xenotransplantation in baboons: comparison with cyclophosphamide. Xenotransplantation. 2004; 11: 112-122.

[101] Cozzi E, Simioni P, Boldrin M, et al. Effects of long-term administration of high-dose recombinant human antithrombin in immunosuppressed primate recipients of porcine xenografts. Transplantation. 2005; 80: 1501-1510.

[102] Moscoso I, Hermida-Prieto M, Manez R, et al. Lack of cross-species transmission of porcine endogenous retrovirus in pig-to-baboon xenotransplantation with sustained depletion of anti-alphagal antibodies. Transplantation. 2005; 79: 777-782.

[103] Chen G, Qian H, Starzl T, et al. Acute rejection is associated with antibodies to non-gal antigens in baboons using gal-knockout pig kidneys. Nat Med. 2005; 11: 1295-1298.

[104] Chen G, Sun H, Yang H, et al. The role of anti-non-gal antibodies in the development of acute humoral xenograft rejection of hDAF transgenic porcine kidneys in baboons receiving anti-gal antibody neutralization therapy. Transplantation. 2006; 81: 273-283.

[105] Ezzelarab M, Garcia B, Azimzadeh A, et al. The innate immune response and activation of coagulation in alpha1,3-galactosyltransferase gene-knockout xenograft recipients. Transplantation. 2009; 87: 805-812.

[106] Knosalla C, Yazawa K, Behdad A, et al. Renal and cardiac endothelial heterogeneity impact acute vascular rejection in pig-to-baboon xenotransplantation. Am J Transplant. 2009; 9: 1006-1016.

[107] Le Bas-Bernardet S, Tillou X, Poirier N, et al. Xenotransplantation of galactosyl-transferase knockout, CD55, CD59, CD39, and fucosyl-transferase transgenic pig kidneys into baboons. Transplant Proc. 2011; 43: 3426-3430.

[108] Nishimura H, Scalea J, Wang Z, et al. First experience with the use of a recombinant CD3 immunotoxin as induction therapy in pig-to-primate xenotransplantation: the effect of T-cell depletion on outcome. Transplantation. 2011; 92: 641-647.

[109] Spiezia L, Boldrin M, Radu C, et al. Thromboelastographic evaluation of coagulative profiles in pig-to-monkey kidney xenotransplantation. Xenotransplantation. 2013; 20: 89-99.

[110] Sekijima M, Waki S, Sahara H, et al. Results of life-supporting galactosyltransferase knockout kidneys in cynomolgus monkeys using two different sources of galactosyltransferase knockout swine. Transplantation. 2014; 98: 419-426.

[111] Azimzadeh AM, Kelishadi SS, Ezzelarab MB, et al. Early graft failure of GalTKO pig organs in baboons is reduced by expression of a human complement pathway-regulatory protein. Xenotransplantation. 2015; 22: 310-316.

[112] Higginbotham L, Mathews D, Breeden CA, et al. Pre-transplant antibody screening and anti-CD154 costimulation blockade promote long-term xenograft survival in a pig-to-primate kidney transplant model. Xenotransplantation. 2015; 22: 221-230.

[113] Rivard CJ, Tanabe T, Lanaspa MA, et al. Upregulation of CD80 on glomerular podocytes plays an important role in development of proteinuria following pig-to-baboon xeno-renal transplantation—an experimental study. Transpl Int. 2018; 31: 1164-1177.

[114] Adams AB, Kim SC, Martens GR, et al. Xenoantigen deletion and chemical immunosuppression can prolong renal xenograft survival. Ann Surg. 2018; 268: 564-573.

[115] Yamamoto T, Hara H, Foote J, et al. Life-supporting kidney xenotransplantation from genetically engineered pigs in baboons: a comparison of two immunosuppressive regimens. Transplantation. 2019; 103: 2090-2104.

[116] Adams AB, Lovasik BP, Faber DA, et al. Anti-C5 antibody Tesidolumab reduces early antibody-mediated rejection and prolongs survival in renal xenotransplantation. Ann Surg. 2021; 274: 473-480.

[117] Iwase H, Jagdale A, Yamamoto T, et al. Evidence suggesting that deletion of expression of N-glycolylneuraminic acid (Neu5Gc) in the organ-source pig is associated with increased antibody-mediated rejection of kidney transplants in baboons. Xenotransplantation. 2021; 28:e12700.

[118] Takeuchi K, Ariyoshi Y, Shimizu A, et al. Expression of human CD47 in pig glomeruli prevents proteinuria and prolongs graft survival following pig-to-baboon xenotransplantation. Xenotransplantation. 2021; 28:e12708.

[119] Hwang CS, MacConmara M, Desai DM. Pediatric abdominal organ transplantation. Surg Clin North Am. 2019; 99: 73-85.

[120] Montgomery RA, Stern JM, Lonze BE, et al. Results of two cases of pig-to-human kidney xenotransplantation. N Engl J Med. 2022; 386: 1889-1898.

[121] Porrett PM, Orandi BJ, Kumar V, et al. First clinical-grade porcine kidney xenotransplant using a human decedent model. Am J Transplant. 2022; 22: 1037-1053.

[122] Locke JE, Kumar V, Anderson D, Porrett PM. Normal graft function after pig-to-human kidney xenotransplant. JAMA Surg. 2023; 158: 1106-1108.

[123] Jones-Carr ME, Fatima H, Kumar V, et al. C5 inhibition with eculizumab prevents thrombotic microangiopathy in a case series of pig-to-human kidney xenotransplantation. J Clin Invest. 2024; 134:e175996.

[124] Kawai T, Williams WW, Elias N, et al. Xenotransplantation of a porcine kidney for end-stage kidney disease. N Engl J Med. 2025; 392: 1933-1940.

[125] Levan ML, Ahuja HK, Reed RD, et al. Beyond theory and into practice: a qualitative study of the experiences of xenotransplant recipients. Am J Transplant. 2026; 26(2): 349-358.

[126] Cohen J. The organ farm. Science. 2025; 388: 906-912.

[127] Xijing Hospital. First Case of Genetically Edited Pig-to-Human Kidney Xenotransplantation in Asia Achieves Over 200 Days of Survival. Fourth Military Medical University; 2025. https://www.fmmu.edu.cn/news/info/1004/174352.htm

[128] Shimizu A, Yamada K. Histopathology of xenografts in pig to non-human primate discordant xenotransplantation. Clin Transpl. 2010; 24(suppl. 22): 11-15.

[129] Wei X, Li S, Wang S, et al. Peptidomes and structures illustrate how SLA-I micropolymorphism influences the preference of binding peptide length. Front Immunol. 2022; 13:820881.

[130] Ladowski JM, Hara H, Cooper DKC. The role of SLAs in xenotransplantation. Transplantation. 2021; 105: 300-307.

[131] Niu D, Wei HJ, Lin L, et al. Inactivation of porcine endogenous retrovirus in pigs using CRISPR-Cas9. Science. 2017; 357: 1303-1307.

[132] Meyer BJ, Kunz N, Seki S, et al. Immunologic and genetic contributors to CD46-dependent immune dysregulation. J Clin Immunol. 2023; 43: 1840-1856.

[133] Martínez-Alarcón L, Liarte S, Quereda JJ, et al. Profiling human CD55 transgene performance assists in selecting best suited specimens and tissues for swine organ xenotransplantation. Biology. 2021; 10:747.

[134] Ménoret S, Plat M, Blancho G, et al. Characterization of human CD55 and CD59 transgenic pigs and kidney xenotransplantation in the pig-to-baboon combination. Transplantation. 2004; 77(9): 1468-1471.

[135] Sun X, Funk CD, Deng C, Sahu A, Lambris JD, Song WC. Role of decay-accelerating factor in regulating complement activation on the erythrocyte surface as revealed by gene targeting. Proc Natl Acad Sci USA. 1999; 96: 628-633.

[136] Weiss EH, Lilienfeld BG, Müller S, et al. HLA-E/human beta2-microglobulin transgenic pigs: protection against xenogeneic human anti-pig natural killer cell cytotoxicity. Transplantation. 2009; 87: 35-43.

[137] Roberts V, Campbell DJ, Lu B, Chia J, Cowan PJ, Dwyer KM. The differential effect of apyrase treatment and hCD39 overexpression on chronic renal fibrosis after ischemia-reperfusion injury. Transplantation. 2017; 101: e194-e204.

[138] Dwyer KM, Robson SC, Nandurkar HH, et al. Thromboregulatory manifestations in human CD39 transgenic mice and the implications for thrombotic disease and transplantation. J Clin Invest. 2004; 113: 1440-1446.

[139] Lee KF, Lu B, Roussel JC, et al. Protective effects of transgenic human endothelial protein C receptor expression in murine models of transplantation. Am J Transplant. 2012; 12: 2363-2372.

[140] Zoldhelyi P, McNatt J, Shelat HS, Yamamoto Y, Chen ZQ, Willerson JT. Thromboresistance of balloon-injured porcine carotid arteries after local gene transfer of human tissue factor pathway inhibitor. Circulation. 2000; 101: 289-295.

[141] Crikis S, Zhang XM, Dezfouli S, et al. Anti-inflammatory and anticoagulant effects of transgenic expression of human thrombomodulin in mice. Am J Transplant. 2010; 10: 242-250.

[142] Wu CC, Lu KC, Chen JS, et al. HO-1 induction ameliorates experimental murine membranous nephropathy: anti-oxidative, anti-apoptotic and immunomodulatory effects. Nephrol Dial Transplant. 2008; 23: 3082-3090.

[143] Petersen B, Ramackers W, Lucas-Hahn A, et al. Transgenic expression of human heme oxygenase-1 in pigs confers resistance against xenograft rejection during ex vivo perfusion of porcine kidneys. Xenotransplantation. 2011; 18: 355-368.

[144] Tenhunen R, Ross ME, Marver HS, Schmid R. Reduced nicotinamide-adenine dinucleotide phosphate dependent biliverdin reductase: partial purification and characterization. Biochemistry. 1970; 9: 298-303.

[145] Ryter SW, Choi AM. Carbon monoxide: present and future indications for a medical gas. Korean J Intern Med. 2013; 28: 123-140.

[146] Zammit NW, McDowell J, Warren J, et al. TNFAIP3 reduction-of-function drives female infertility and CNS inflammation. Front Immunol. 2022; 13:811525.

[147] Braza F, Brouard S, Chadban S, Goldstein DR. Role of TLRs and DAMPs in allograft inflammation and transplant outcomes. Nat Rev Nephrol. 2016; 12: 281-290.

[148] Krüger B, Krick S, Dhillon N, et al. Donor toll-like receptor 4 contributes to ischemia and reperfusion injury following human kidney transplantation. Proc Natl Acad Sci USA. 2009; 106: 3390-3395.

[149] Lakkaraja M, Scordo M, Mauguen A, et al. Antithymocyte globulin exposure in CD34+ T-cell-depleted allogeneic hematopoietic cell transplantation. Blood Adv. 2022; 6: 1054-1063.

[150] Mok S, Ağaç Çobanoğlu D, Liu H, Mancuso JJ, Allison JP. Post-immunotherapy CTLA-4 Ig treatment improves antitumor efficacy. Proc Natl Acad Sci USA. 2024; 121:e2404661121.

[151] Dé Tran QH, Guay E, Chartier S, Tousignant J. Tacrolimus in dermatology. J Cutan Med Surg. 2001; 5: 329-335.

[152] Migita K, Eguchi K, Kawabe Y, Tsukada T, Mizokami A, Nagataki S. FK506 augments activation-induced programmed cell death of T lymphocytes in vivo. J Clin Invest. 1995; 96: 727-732.

[153] Camara NOS, Alves-Filho JC, de Moraes-Vieira PM, Andrade-Oliveira V. Essential Aspects of Immunometabolism in Health and Disease. Springer; 2022.

[154] Laboux T, Maanaoui M, Allain F, et al. Hemolysis is associated with altered heparan sulfate of the endothelial glycocalyx and with local complement activation in thrombotic microangiopathies. Kidney Int. 2023; 104: 353-366.

[155] Berger M, Lefaucheur C, Jordan SC. Update on C1 esterase inhibitor in human solid organ transplantation. Transplantation. 2019; 103: 1763-1775.

[156] Vogel CW, Vogel C. Recombinant cobra venom factor. Mol Immunol. 2004; 41: 191-199.

[157] Mannes M, Pechtl V, Hafner S, et al. Complement and platelets: prothrombotic cell activation requires membrane attack complex-induced release of danger signals. Blood Adv. 2023; 7: 6367-6380.

[158] de Jong S, Tang J, Clark SJ. Age-related macular degeneration: a disease of extracellular complement amplification. Immunol Rev. 2023; 313: 279-297.

[159] Bender M, Abicht J-M, Reichart B, et al. Combination of anti-CD40 and anti-CD40L antibodies as co-stimulation blockade in preclinical cardiac xenotransplantation. Biomedicine. 2024; 12: 1927.

[160] Mohiuddin MM, Singh AK, Corcoran PC, et al. Role of anti-CD40 antibody-mediated costimulation blockade on non-gal antibody production and heterotopic cardiac xenograft survival in a GTKO.hCD46Tg pig-to-baboon model. Xenotransplantation. 2014; 21: 35-45.

[161] Liu D, Ford ML. CD11b is a novel alternate receptor for CD154 during alloimmunity. Am J Transplant. 2020; 20: 2216-2225.

[162] O'Neill NA, Zhang T, Braileanu G, et al. Comparative evaluation of alphaCD40 (2C10R4) and alphaCD154 (5C8H1 and IDEC-131) in a nonhuman primate cardiac allotransplant model. Transplantation. 2017; 101: 2038-2047.

[163] Fähnrich A, Klein S, Sergé A, et al. CD154 costimulation shifts the local T-cell receptor repertoire not only during thymic selection but also during peripheral T-dependent humoral immune responses. Front Immunol. 2018; 9:1019.

[164] Ferrer IR, Wagener ME, Song M, Ford ML. CD154 blockade alters innate immune cell recruitment and programs alloreactive CD8+ T cells into KLRG-1high short-lived effector T cells. PLoS One. 2012; 7:e40559.

[165] Pinelli DF, Wagener ME, Liu D, et al. An anti-CD154 domain antibody prolongs graft survival and induces Foxp3(+) iTreg in the absence and presence of CTLA-4 Ig. Am J Transplant. 2013; 13: 3021-3030.

[166] Lassiter G, Otsuka R, Hirose T, et al. TNX-1500, a crystallizable fragment-modified anti-CD154 antibody, prolongs nonhuman primate renal allograft survival. Am J Transplant. 2023; 23: 1171-1181.

[167] Fan GH, Zhang CZ, Gao FQ, et al. A mixed blessing for liver transplantation patients—rapamycin. Hepatobiliary Pancreat Dis Int. 2023; 22: 14-21.

[168] Lamming DW, Anderson RM. Strength in diversity: intra-cellular metabolite sharing enhances longevity. Cell. 2023; 186: 8-9.

[169] Naseri B, Mardi A, Khosrojerdi A, et al. Everolimus treatment enhances inhibitory immune checkpoint molecules' expression in monocyte-derived dendritic cells. Hum Immunol. 2024; 85:110798.

[170] Zhang X, Han S, Kang Y, et al. SAHA, an HDAC inhibitor, synergizes with tacrolimus to prevent murine cardiac allograft rejection. Cell Mol Immunol. 2012; 9: 390-398.

[171] Mohiuddin MM, Singh AK, Corcoran PC, et al. Chimeric 2C10R4 anti-CD40 antibody therapy is critical for long-term survival of GTKO.hCD46.hTBM pig-to-primate cardiac xenograft. Nat Commun. 2016; 7: 11138.

[172] Kim CH. Glycoimmunology in Xenotransplantation. Springer; 2024.

[173] Roodnat JI, Hilbrands LB, Hené RJ, et al. 15-year follow-up of a multicenter, randomized, calcineurin inhibitor withdrawal study in kidney transplantation. Transplantation. 2014; 98: 47-53.

[174] Opelz G, Döhler B. Association between steroid dosage and death with a functioning graft after kidney transplantation. Am J Transplant. 2013; 13: 2096-2105.

[175] Montgomery RA, Hardy MA, Jordan SC, et al. Consensus opinion from the antibody working group on the diagnosis, reporting, and risk assessment for antibody-mediated rejection and desensitization protocols. Transplantation. 2004; 78: 181-185.

[176] Lucas JG, Co JP, Nwaogwugwu UT, Dosani I, Sureshkumar KK. Antibody-mediated rejection in kidney transplantation: an update. Expert Opin Pharmacother. 2011; 12: 579-592.

[177] Rocha PN, Butterly DW, Greenberg A, et al. Beneficial effect of plasmapheresis and intravenous immunoglobulin on renal allograft survival of patients with acute humoral rejection. Transplantation. 2003; 75: 1490-1495.

[178] Faguer S, Kamar N, Guilbeaud-Frugier C, et al. Rituximab therapy for acute humoral rejection after kidney transplantation. Transplantation. 2007; 83: 1277-1280.

[179] Kenison JE, Stevens NA, Quintana FJ. Therapeutic induction of antigen-specific immune tolerance. Nat Rev Immunol. 2024; 24: 338-357.

[180] Lu L, Barbi J, Pan F. The regulation of immune tolerance by FOXP3. Nat Rev Immunol. 2017; 17: 703-717.

[181] Mansourabadi AH, Khosroshahi LM, Noorbakhsh F, Amirzargar A. Cell therapy in transplantation: a comprehensive review of the current applications of cell therapy in transplant patients with the focus on Tregs, CAR Tregs, and mesenchymal stem cells. Int Immunopharmacol. 2021; 97:107669.

[182] Kremer J, Henschel P, Simon D, et al. Membrane-bound IL-2 improves the expansion, survival, and phenotype of CAR Tregs and confers resistance to calcineurin inhibitors. Front Immunol. 2022; 13:1005582.

[183] Thomson AW, Metes DM, Ezzelarab MB, Raïch-Regué D. Regulatory dendritic cells for human organ transplantation. Transplant Rev. 2019; 33: 130-136.

[184] Tunbridge MJ, Luo X, Thomson AW. Negative vaccination strategies for promotion of transplant tolerance. Transplantation. 2024; 108: 1715-1729.

[185] Hutchinson JA, Riquelme P, Geissler EK, Fändrich F. Human regulatory macrophages. Methods Mol Biol. 2011; 677: 181-192.

[186] Carretero-Iglesia L, Hill M, Cuturi MC. Generation and characterization of mouse regulatory macrophages. Methods Mol Biol. 2016; 1371: 89-100.

[187] Su S, Zhao J, Xing Y, et al. Immune checkpoint inhibition overcomes ADCP-induced immunosuppression by macrophages. Cell. 2018; 175: 442-457.e23.

[188] Riquelme P, Hutchinson JA. Novel molecules mediate specialized functions of human regulatory macrophages. Curr Opin Organ Transplant. 2018; 23: 533-537.

[189] Guo F, Hu M, Huang D, et al. Human regulatory macrophages are potent in suppression of the xenoimmune response via indoleamine-2,3-dioxygenase-involved mechanism(s). Xenotransplantation. 2017; 24:e12326.

[190] Hutchinson JA, Riquelme P, Sawitzki B, et al. Cutting edge: immunological consequences and trafficking of human regulatory macrophages administered to renal transplant recipients. J Immunol. 2011; 187: 2072-2078.

[191] Hutchinson JA, Riquelme P, Brem-Exner BG, et al. Transplant acceptance-inducing cells as an immune-conditioning therapy in renal transplantation. Transpl Int. 2008; 21: 728-741.

[192] Hutchinson JA, Gövert F, Riquelme P, et al. Administration of donor-derived transplant acceptance-inducing cells to the recipients of renal transplants from deceased donors is technically feasible. Clin Transpl. 2009; 23: 140-145.

[193] Koyama I, Nadazdin O, Boskovic S, et al. Depletion of CD8 memory T cells for induction of tolerance of a previously transplanted kidney allograft. Am J Transplant. 2007; 7: 1055-1061.

[194] Hotta K, Oura T, Dehnadi A, et al. Long-term nonhuman primate renal allograft survival without ongoing immunosuppression in recipients of delayed donor bone marrow transplantation. Transplantation. 2018; 102(4): e128-e136.

[195] Dery KJ, Górski A, Międzybrodzki R, Farmer DG, Kupiec-Weglinski JW. Therapeutic perspectives and mechanistic insights of phage therapy in allotransplantation. Transplantation. 2021; 105: 1449-1458.

[196] Boratyńska M, Szewczyk Z, Weber-Dąbrowska B. The clinical evaluation of bacteriophage treatment of urinary infections. Postepy Med Klin Dosw. 1994; 3: 7-11.

[197] Kuipers S, Ruth MM, Mientjes M, de Sévaux RG, van Ingen J. A Dutch case report of successful treatment of chronic relapsing urinary tract infection with bacteriophages in a renal transplant patient. Antimicrob Agents Chemother. 2019; 64:e01281-19.

[198] Rostkowska OM, Międzybrodzki R, Miszewska-Szyszkowska D, Górski A, Durlik M. Treatment of recurrent urinary tract infections in a 60-year-old kidney transplant recipient. The use of phage therapy. Transpl Infect Dis. 2020; 23:e13391.

[199] Nerger BA, Sinha S, Lee NN, et al. 3D hydrogel encapsulation regulates nephrogenesis in kidney organoids. Adv Mater. 2024; 36:e2308325.

[200] Sharpe AH, Pauken KE. The diverse functions of the PD1 inhibitory pathway. Nat Rev Immunol. 2018; 18: 153-167.

[201] Yang EY, Kronenfeld JP, Gattás-Asfura KM, Bayer AL, Stabler CL. Engineering an “infectious” T(reg) biomimetic through chemoselective tethering of TGF-β1 to PEG brush surfaces. Biomaterials. 2015; 67: 20-31.

[202] Kinney SM, Ortaleza K, Won S-Y, Licht BJM, Sefton MV. Immunomodulation by subcutaneously injected methacrylic acid-based hydrogels and tolerogenic dendritic cells in a mouse model of autoimmune diabetes. Biomaterials. 2023; 301:122265.

[203] Lin X, Wang Y, Peng J, et al. Application prospects of organoid-on-chips technology in xenotransplantation. Organ Transplant. 2025; 16: 502-508.

[204] Kroll KT, Mata MM, Homan KA, et al. Immune-infiltrated kidney organoid-on-chip model for assessing T cell bispecific antibodies. Proc Natl Acad Sci USA. 2023; 120:e2305322120.

[205] Borges TJ, Ganchiku Y, Aceves JO, et al. Exploring immune response toward transplanted human kidney tissues assembled from organoid building blocks. iScience. 2024; 27:110957.

[206] Li M, Guo X, Cheng L, et al. Porcine kidney organoids derived from naïve-like embryonic stem cells. Int J Mol Sci. 2024; 25: 682.

[207] Takasato M, Er PX, Chiu HS, et al. Kidney organoids from human iPS cells contain multiple lineages and model human nephrogenesis. Nature. 2015; 526: 564-568.

[208] Przepiorski A, Sander V, Tran T, et al. A simple bioreactor-based method to generate kidney organoids from pluripotent stem cells. Stem Cell Rep. 2018; 11: 470-484.

[209] Skylar-Scott MA, Uzel SGM, Nam LL, et al. Biomanufacturing of organ-specific tissues with high cellular density and embedded vascular channels. Sci Adv. 2019; 5:eaaw2459.

[210] Garreta E, Prado P, Tarantino C, et al. Fine tuning the extracellular environment accelerates the derivation of kidney organoids from human pluripotent stem cells. Nat Mater. 2019; 18: 397-405.

[211] Bonnans C, Chou J, Werb Z. Remodelling the extracellular matrix in development and disease. Nat Rev Mol Cell Biol. 2014; 15: 786-801.

[212] DeForest CA, Anseth KS. Photoreversible patterning of biomolecules within click-based hydrogels. Angew Chem Int Ed. 2012; 51: 1816-1819.

[213] Kim JW, Nam SA, Yi J, et al. Kidney decellularized extracellular matrix enhanced the vascularization and maturation of human kidney organoids. Adv Sci. 2022; 9:e2103526.

[214] Tabibzadeh N, Morizane R. Advancements in therapeutic development: kidney organoids and organs on a chip. Kidney Int. 2024; 105: 702-708.

[215] Ingber DE. Human organs-on-chips for disease modelling, drug development and personalized medicine. Nat Rev Genet. 2022; 23: 467-491.

[216] Matsunari H, Watanabe M, Hasegawa K, et al. Compensation of disabled organogeneses in genetically modified pig fetuses by blastocyst complementation. Stem Cell Rep. 2020; 14: 21-33.

[217] Al-Massarani G, Vacher-Coponat H, Paul P, et al. Kidney transplantation decreases the level and procoagulant activity of circulating microparticles. Am J Transplant. 2009; 9: 550-557.

[218] Qamri Z, Pelletier R, Foster J, et al. Early posttransplant changes in circulating endothelial microparticles in patients with kidney transplantation. Transplant Immunol. 2014; 31: 60-64.

[219] Park J, Lin HY, Assaker JP, et al. Integrated kidney exosome analysis for the detection of kidney transplant rejection. ACS Nano. 2017; 11: 11041-11046.

[220] Reichart B, Längin M, Denner J, Schwinzer R, Cowan PJ, Wolf E. Pathways to clinical cardiac xenotransplantation. Transplantation. 2021; 105: 1930-1943.

[221] Wu D, Zhao XS, Zhao HF, Xie JH, Wei HJ, Zhu NW. New hope for the treatment of severe skin injury: genetically engineered porcine skin xenotransplantation. Xenotransplantation. 2025; 32:e70057.

[222] Zhang Y, Lian X, Xu H, et al. OrgXenomics: an integrated proteomic knowledge base for patient-derived organoid and xenograft. Nucleic Acids Res. 2025; 53: D504-D515.

[223] Lin J, Li Y, Fang T, et al. Substantial decline of organ preservation fluid contamination following adoption of ischemia-free liver transplantation: a post-hoc analysis. Int J Surg. 2024; 110: 2855-2864.

[224] Chen Y, Yang T, Wang S, et al. Hemocompatible nucleosome-inspired heparin-mimicking hydrogel microspheres for safe and efficient extracorporeal removal of circulating histones in critically ill patients. J Mater Chem B. 2025; 13: 2366-2381.

[225] Sheng D, Guo S, Li A, et al. NO-releasing metal-organic framework-based composite coatings with heparin-mimicking copolymers on titanium substrates: impact on vascular cell behavior. Biomacromolecules. 2025; 26: 2540-2552.

[226] Hawthorne WJ, Pierson RN III, Buhler L, et al. International xenotransplantation association (IXA) position paper on the history, current status, and regulation of xenotransplantation. Transplantation. 2025; 109: 1301-1312.

[227] Hu X, Cooper DKC, Golshayan D, et al. Xenotransplantation: from proof of concept to clinical reality. Swiss Med Wkly. 2026; 155:4945.

[228] Meier RPH, Pierson RN III, Fishman JA, et al. International xenotransplantation association (IXA) position paper on kidney xenotransplantation. Xenotransplantation. 2025; 32:e70014.

Rights & permissions

2026 The Author(s). Animal Models and Experimental Medicine published by John Wiley & Sons Australia, Ltd on behalf of The Chinese Association for Laboratory Animal Sciences.