Background Recent survivals of our pig-to-baboon kidney xenotransplants have been markedly shorter than the graft survivals we previously reported. The discovery of high levels of porcine CMV (pCMV) in one of the rejected xenografts led us to evaluate whether this reduction in graft survival might be due to the inadvertent introduction of pCMV into our GalT-KO swine herd. Methods Archived frozen sections of xeno-kidney grafts over the past 10 years were analyzed for the presence of pCMV, using real-time PCR. Three prospective pig-to-baboon renal transplants using kidneys from swine delivered by caesarian section (C-section) and raised in isolation were likewise analyzed. Results Kidney grafts from which 8 of the 18 archived samples were derived were found to be pCMV-negative, had a mean graft survival of 48.3 days and were from transplants performed before 2008. None had shown signs of DIC and were lost due to either proteinuria or infectious complications. In contrast, 10 of the archived samples were pCMV positive, were from kidney transplants with a mean graft survival of 14.1 days, had been performed after 2008 and had demonstrated early vascular changes and decreased platelet counts. Three prospective xenografts from swine delivered by C-section were pCMV negative and survived an average of 53.0 days. Conclusions Decreased survivals of GalT-KO renal xenografts in this laboratory correlate temporally with latent pCMV in the donor animals and pCMV in the rejected xeno-kidneys. Transmission of pCMV to swine offspring may be avoided by C-section delivery and scrupulous isolation of donor animals.

Background Various durations of survival have been observed in the xenotransplantation of life-supporting alpha-1,3-galactosyltransferase knockout (GalT-KO) porcine kidneys into nonhuman primates (NHPs). While others have demonstrated loss of GalT-KO transplanted kidneys within two weeks, we have reported an average survival of 51 days with the co-transplantation of the kidney and vascularized thymus and an average of 29 days with the kidney alone. In order to determine the factors responsible for this difference in survival time, we performed xenogeneic kidney transplantations into cynomolgus monkeys with an anti-CD40L-based regimen using two different strains of GalT-KO swine, one derived from MGH-Miniature swine and the other obtained from Meji University. Materials and Methods Eight cynomolgus moneys received GalT-KO kidneys. Three kidney grafts were from MGH/NIBS GalT-KO pigs and 5 GalT-KO grafts were from MEIJI GalT-KO swine. All cynomolgus recipients were treated identically. Results Recipients of kidneys from the MGH GalT-KO swine, produced by nuclear transfer in Japan, survived an average of 28.7 days, while recipients of MEIJI GalT-KO swine survived an average of 9.2 days. Among the differences between these two groups, one potentially revealing disparity was that the MEIJI swine were positive for porcine-CMV, while the MGH-derived swine were negative. Conclusions This is the first study comparing renal xenotransplantation from two different sources of GalT-KO swine into NHPs at a single center. The results demonstrate that porcine-CMV may be responsible for early loss of GalTKO swine kidney xenografts.

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We have previously reported that co-transplantation of the kidney with vascularized donor thymus from α-1,3-galactosyltransferase gene knockout pigs with an anti-CD154 with rituximab-based regimen led to improved xenograft survival in baboons with donor-specific unresponsiveness. However, nephrotic syndrome emerged as a complication in which the glomeruli showed mild mesangial expansion with similarities to minimal change disease (MCD) in humans. Since MCD is associated with CD80 expression in glomeruli and elevated urinary excretion, we evaluated a potential role for CD80 in xenograft nephropathy. Study 1 confirmed high urinary CD80 excretion in nephrotic animals with renal xenografts showing CD80 expression in glomeruli. In Study 2, baboons receiving xenografts received CTLA4-Ig once a week from the second postoperative week or no CTLA4-Ig. The non-CTLA4-Ig group developed severe proteinuria with modest mesangial expansion with high urinary excretion of CD80 and documented CD80 expression in glomerular podocytes. All of the recipients in non-CTLA4-Ig groups had to be euthanized before POD 60. In contrast, CTLA4-Ig group showed a marked reduction in proteinuria and survived significantly longer, up to 193 days. These results demonstrate that anti-CD80 targeted therapy represents a promising strategy for reduction of proteinuria following renal xeno-transplantation with improved survival.

Previous attempts of α-1,3-galactocyltransferase knockout (GalTKO) pig bone marrow (BM) transplantation (Tx) into baboons have demonstrated a loss of macro-chimerism within 24 h in most cases. In order to achieve improved engraftment with persistence of peripheral chimerism, we have developed a new strategy of intra-bone BM (IBBM) Tx. Six baboons received GalTKO BM cells, with one-half of the cells transplanted into the bilateral tibiae directly and the remaining cells injected intravenously (IBBM/BM-Tx) with a conditioning immunosuppressive regimen. In order to assess immune responses induced by the combined IBBM/BM-Tx, three recipients received donor SLA-matched GalTKO kidneys in the peri-operative period of IBBM/BM-Tx (Group 1), and the others received kidneys 2 months after IBBM/BM-Tx (Group 2). Peripheral macro-chimerism was continuously detectable for up to 13 days (mean 7.7 days; range 3–13) post-IBBM/BM-Tx and in three animals, macro-chimerism reappeared at days 10, 14 and 21. Pig CFUs, indicating porcine progenitor cell engraftment, were detected in the host BM in four of six recipients on days 14, 15, 19 and 28. In addition, anti-pig unresponsiveness was observed by in vitro assays. GalTKO/pCMV-kidneys survived for extended periods (47 and 60 days). This strategy may provide a potent adjunct for inducing xenogeneic tolerance through BM-Tx.

In this study, we demonstrated the beneficial effects of perioperative administration of anti-HMGB1 antibody in reducing renal IRI in a clinically relevant, large animal model.

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The catechin content in green tea leaves varies according to cultivation conditions such as intensity of solar radiation, temperature, and precipitation, and thus, there is ambiguity about the best harvest time for obtaining optimal functional effects. In this study, the Yabukita (ordinary) and Benifuki varieties, which contain methylated catechin, were used to determine the difference in green tea catechins according to harvest times and tea manufacturing processes. Caffeine determination was also carried out to provide information about green tea intake for all age‐groups of children and pregnant women. Determining the quantity of each catechin was difficult because of degradation, polymerization, and isomerization that had occurred during heat‐drying in the refining process. In addition, the absorption of catechin compounds was tested using miniature swine because of their functional and physiological similarity to humans. Benifuki tea leaves contained epigallocatechin‐3‐(3”‐O‐methyl) gallate (EGCg3”Me) instead of epigallocatechin‐3‐(4”‐O‐methyl) gallate (EGCg4”Me). However, EGCg4”Me was detected during the entire intake period, but EGCg3”Me was not detected in the blood of miniature swine fed Benifuki tea. It is possible that the position of the methyl group was modified by the pig metabolism. Furthermore, caffeine from both Yabukita and Benifuki tea varieties was found to be easily accumulated in miniature swine. These results suggest that nonrefined September–October picking tea (autumn and winter tea) of the Benifuki variety is preferable over the Yabukita variety for consumption by children and pregnant women owing to its lower caffeine content and higher content of methylated catechin.