Uterine autotransplantation in cynomolgus macaques: the first case of pregnancy and delivery.

BACKGROUND: For women with congenital uterine infertility, or for those who have undergone hysterectomy, uterine transplantation is one of the potential treatments to regain fertility. In this study, we utilized a primate model of uterine transplantation, and evaluated the patency of our microsurgical anastomoses, and the perfusion of the transplanted uterus. METHODS: Two female cynomolgus monkeys underwent surgery. We anastomosed two arteries and one vein in Case 1 and two arteries and two veins in Case 2. The arteries used were the uterine arteries and the anastomosis was done to the external iliac artery. We used one of the ovarian veins in both animals, but resected the ovary from the Fallopian tube. Uterine arterial blood flow and uterine size were determined by intraoperative indocyanine green (ICG) angiography and ultrasonography. The biopsy of the uterine cervix was performed after surgery. RESULTS: ICG angiography showed that the unilateral uterine artery perfused the bilateral uterine bodies and cervix. In Case 1, ICG angiography showed the occlusion of one of the anastomosed arteries during the operation and the uterus appeared atrophied 2 months after operation. In Case 2, the transplanted uterus survived and normal menstruation occurred. The animal achieved a natural pregnancy and was delivered by the Caeserean section due to early separation of the placenta. The newborn suffered fetal distress. CONCLUSIONS: These results show the anastomosis of at least the bilateral uterine arteries and the unilateral ovarian vein is required for uterus transplantation. This is the first report of a natural pregnancy in a primate following uterine autotransplantation.

Low-dose In Situ Perfusion With Euro-Collins Solution Is Effective for the Procurement of Marginal Kidney Grafts From Donation After Circulatory Death Donors.

We have adopted a modified method to resuscitate kidneys from donation after circulatory death (DCD) donors with the use of Euro-Collins (EC) solution instead of University of Wisconsin solution. This study aimed to evaluate kidney transplantation (KTx) outcomes of DCD procured with low-dose in situ perfusion using EC solution. PATIENTS AND METHODS: KTx was performed in 8 adults. Kidney grafts were procured following in situ perfusion with approximately 1 L of EC solution and preserved in the solution. The kidney donor profile index value was 88% ± 21%. The terminal creatinine level of the donors was 5.5 ± 3.4 mg/dL. Of the 8 donors, 6 experienced oligoanuria prior to graft procurement. RESULTS: The mean age of the recipients and the hemodialysis vintage were 50 ± 10 years and 161 ± 25 months, respectively. The warm and cold ischemic times were 8.3 ± 7.9 minutes and 8.7 ± 4.3 hours, respectively. All grafts functioned after a delayed graft function of 10.6 ± 6.9 days (2-25 days). There was neither immediate graft function nor primary nonfunction. The patient and graft survivals were both 100% with a terminal creatinine level of 1.3 ± .5 mg/dL. CONCLUSIONS: Kidney grafts procured from DCD donors with a high kidney donor profile index value demonstrated good renal function with an excellent midterm outcome. Low-dose in situ perfusion with EC solution is effective for the procurement of marginal kidney grafts from DCD donors under optimal conditions such as a relatively shorter preservation time.

Trough Level of Mycophenolic Acid Did Not Affect De Novo DSA Development in Kidney Transplantation.

INTRODUCTION: Mycophenolate mofetil has improved long-term outcomes of kidney transplantation. However, the impact of mycophenolic acid (MPA) trough level on the development of de novo donor-specific anti-HLA antibody (DSA) is unclear. We examined the relation between MPA trough level and de novo DSA development. METHOD: We retrospectively studied 617 kidney recipients whose MPA trough level and de novo DSA data were available. All patients underwent primary kidney transplant from living donors from 2008 to 2014, and were chronically treated with a calcineurin inhibitor, mycophenolate mofetil, and +/- steroids. They were equally divided into 4 groups according to the mean trough level of MPA (mMPA) at 1 year post-transplantation: Group 1, mMPA < 2.14 ng/mL (n = 152); Group 2, mMPA 2.14-2.83 ng/mL (n = 157); Group 3, mMPA 2.83-3.57 ng/mL (n = 153); and Group 4, mMPA ≥ 3.57 ng/mL (n = 155). The groups were compared by incidence rate of de novo DSA, graft survival rate, and renal function. RESULTS: The incidence rates of de novo DSA were 33.3% in Group 1, 23.7% in Group 2, 22.9% in Group 3, and 30.3% in Group 4 (P = .158). Although there was no significant difference in graft survival rates, a significant difference of renal functions was noted: the higher the renal function, the lower the MPA trough level. CONCLUSION: The mMPA trough level at 1 year post-transplantation was not statistically associated with the incidence rate of de novo DSA after kidney transplantation.

Treg depletion in non-human primates using a novel diphtheria toxin-based anti-human CCR4 immunotoxin.

Regulatory T cells (Treg) play an important role in modulating the immune response and has attracted increasing attention in diverse fields such as cancer treatment, transplantation and autoimmune diseases. CC chemokine receptor 4 (CCR4) is expressed on the majority of Tregs, especially on effector Tregs. Recently we have developed a diphtheria-toxin based anti-human CCR4 immunotoxin for depleting CCR4(+) cells in vivo. In this study, we demonstrated that the anti-human CCR4 immunotoxin bound and depleted monkey CCR4(+) cells in vitro. We also demonstrated that the immunotoxin bound to the CCR4(+)Foxp3(+) monkey Tregs in vitro. In vivo studies performed in two naive cynomolgus monkeys revealed 78-89% CCR4(+)Foxp3(+) Treg depletion in peripheral blood lasting approximately 10 days. In lymph nodes, 89-96% CCR4(+)Foxp3(+) Tregs were depleted. No effect was observed in other cell populations including CD8(+) T cells, other CD4(+) T cells, B cells and NK cells. To our knowledge, this is the first agent that effectively depleted non-human primate (NHP) Tregs. This immunotoxin has potential to deplete effector Tregs for combined cancer treatment.

Induced regulatory T cells in allograft tolerance via transient mixed chimerism.

Successful induction of allograft tolerance has been achieved in nonhuman primates (NHPs) and humans via induction of transient hematopoietic chimerism. Since allograft tolerance was achieved in these recipients without durable chimerism, peripheral mechanisms are postulated to play a major role. Here, we report our studies of T cell immunity in NHP recipients that achieved long-term tolerance versus those that rejected the allograft (AR). All kidney, heart, and lung transplant recipients underwent simultaneous or delayed donor bone marrow transplantation (DBMT) following conditioning with a nonmyeloablative regimen. After DBMT, mixed lymphocyte culture with CFSE consistently revealed donor-specific loss of CD8+ T cell responses in tolerant (TOL) recipients, while marked CD4+ T cell proliferation in response to donor antigens was found to persist. Interestingly, a significant proportion of the proliferated CD4+ cells were FOXP3+ in TOL recipients, but not in AR or naive NHPs. In TOL recipients, CD4+FOXP3+ cell proliferation against donor antigens was greater than that observed against third-party antigens. Finally, the expanded Tregs appeared to be induced Tregs (iTregs) that were converted from non-Tregs. These data provide support for the hypothesis that specific induction of iTregs by donor antigens is key to long-term allograft tolerance induced by transient mixed chimerism.

New-Onset Diabetes Mellitus After Transplantation in a Cynomolgus Macaque (Macaca fasicularis).

A 5.5-y-old intact male cynomolgus macaque (Macaca fasicularis) presented with inappetence and weight loss 57 d after heterotopic heart and thymus transplantation while receiving an immunosuppressant regimen consisting of tacrolimus, mycophenolate mofetil, and methylprednisolone to prevent graft rejection. A serum chemistry panel, a glycated hemoglobin test, and urinalysis performed at presentation revealed elevated blood glucose and glycated hemoglobin (HbA1c) levels (727 mg/dL and 10.1%, respectively), glucosuria, and ketonuria. Diabetes mellitus was diagnosed, and insulin therapy was initiated immediately. The macaque was weaned off the immunosuppressive therapy as his clinical condition improved and stabilized. Approximately 74 d after discontinuation of the immunosuppressants, the blood glucose normalized, and the insulin therapy was stopped. The animal's blood glucose and HbA1c values have remained within normal limits since this time. We suspect that our macaque experienced new-onset diabetes mellitus after transplantation, a condition that is commonly observed in human transplant patients but not well described in NHP. To our knowledge, this report represents the first documented case of new-onset diabetes mellitus after transplantation in a cynomolgus macaque.

Heart transplantation: challenges facing the field.

There has been significant progress in the field of heart transplantation over the last 45 years. The 1-yr survival rates following heart transplantation have improved from 30% in the 1970s to almost 90% in the 2000s. However, there has been little change in long-term outcomes. This is mainly due to chronic rejection, malignancy, and the detrimental side effects of chronic immunosuppression. In addition, over the last decade, new challenges have arisen such as increasingly complicated recipients and antibody-mediated rejection. Most, if not all, of these obstacles to long-term survival could be prevented or ameliorated by the induction of transplant tolerance wherein the recipient's immune system is persuaded not to mount a damaging immune response against donor antigens, thus eliminating the need for chronic immunosuppression. However, the heart, as opposed to other allografts like kidneys, appears to be a tolerance-resistant organ. Understanding why organs like kidneys and livers are prone to tolerance induction, whereas others like hearts and lungs are tolerance-resistant, could aid in our attempts to achieve long-term, immunosuppression-free survival in human heart transplant recipients. It could also advance the field of pig-to-human xenotransplantation, which, if successful, would eliminate the organ shortage problem. Of course, there are alternative futures to the field of heart transplantation that may include the application of total mechanical support, stem cells, or bioengineered whole organs. Which modality will be the first to reach the ultimate goal of achieving unlimited, long-term, circulatory support with minimal risk to longevity or lifestyle is unknown, but significant progress in being made in each of these areas.

Innate immunity and resistance to tolerogenesis in allotransplantation.

The development of immunosuppressive drugs to control adaptive immune responses has led to the success of transplantation as a therapy for end-stage organ failure. However, these agents are largely ineffective in suppressing components of the innate immune system. This distinction has gained in clinical significance as mounting evidence now indicates that innate immune responses play important roles in the acute and chronic rejection of whole organ allografts. For instance, whereas clinical interest in natural killer (NK) cells was once largely confined to the field of bone marrow transplantation, recent findings suggest that these cells can also participate in the acute rejection of cardiac allografts and prevent tolerance induction. Stimulation of Toll-like receptors (TLRs), another important component of innate immunity, by endogenous ligands released in response to ischemia/reperfusion is now known to cause an inflammatory milieu favorable to graft rejection and abrogation of tolerance. Emerging data suggest that activation of complement is linked to acute rejection and interferes with tolerance. In summary, the conventional wisdom that the innate immune system is of little importance in whole organ transplantation is no longer tenable. The addition of strategies that target TLRs, NK cells, complement, and other components of the innate immune system will be necessary to eventually achieve long-term tolerance to human allograft recipients.