Daily Cyclosporine Research Articles

Endoscopic injection of skeletal muscle–derived cells augments gut smooth muscle sphincter function: implications for a novel therapeutic approach

Sphincter function is a common problem in gastroenterology and leads to disorders such as GERD and fecal incontinence. We hypothesized that transplantation of skeletal muscle-derived cells (MDCs) into GI sphincters may improve their function, leading to a more physiological approach to treating these disorders. We performed experiments to test the potential of MDCs to survive and differentiate within the GI smooth muscle in order to gain further knowledge on the biology of skeletal muscle transplantation in GI smooth muscle sphincters as well as to test the safety and feasibility of endoscopic injection of MDCs in a large animal model. Animal laboratory. Adult male Sprague-Dawley rats and adult male beagle dogs were used. Rat-derived and dog-derived MDCs were prepared in vitro and labeled with DiI. DiI-labeled, rat-derived MDCs (200,000/4 muL phosphate buffered saline solution) were injected bilaterally in the pyloric wall of rats, and survival, differentiation, and in vitro contractility were assessed 1 month after transplantation. Dog-derived MDCs (4.0 x 10(6) cells) were also injected into the lower esophageal sphincter of 3 beagle dogs by using a standard variceal sclerotherapy needle after baseline esophageal manometry and pH monitoring. The dogs were treated with daily cyclosporine, and 2 weeks later esophageal manometry was repeated and the esophagus was examined histologically. Differentiation of grafted cells was assessed by immunofluorescence, using specific antibodies to markers of the smooth muscle phenotype (smooth muscle actin) and of the skeletal muscle phenotype (skeletal muscle myosin). In rats, grafted MDCs were visualized based on DiI fluorescence and were found to be localized within the muscle wall and in the muscularis mucosa. In vitro organ bath studies showed a significant increase in the contractile response of the pyloric sphincter to exogenous acetylcholine. In dogs, MDC injection resulted in a significant increase in baseline lower esophageal sphincter pressure. Further, in 1 dog with significant baseline acid reflux, MDC injection resulted in a reduction of acid reflux, with the fraction of time with pH <4 decreasing from 26.5% to 1.5%. Transplanted MDCs were seen adding bulk to the lower esophageal area and were well-integrated into the surrounding tissue. Immunofluorescence analysis revealed weak expression of skeletal muscle myosin in grafted MDCs and no expression of smooth muscle actin in either rats or dogs. Animal study. MDCs can survive and integrate into GI smooth muscle and augment their contractile response. Thus, they may have potential for the treatment of a variety of conditions.

Daily Topical Tacrolimus Therapy Prevents Skin Rejection in a Rodent Hind Limb Allograft Model

Skin is the most immunogenic component of a composite tissue allograft. Topical immunotherapy is an attractive therapeutic modality with which to provide local immunosuppression, with minimal systemic toxicity. The present study was performed to investigate the potential of topical tacrolimus to prolong survival of the skin component of a composite tissue allograft. Wistar Furth-to-Lewis rat orthotopic hind limb transplants were performed. Group I consisted of rats treated with topical tacrolimus; group II, antilymphocyte serum plus 21 days cyclosporine; and group III, antilymphocyte serum plus 21 days of cyclosporine plus topical tacrolimus. In group IV, tacrolimus levels in blood, skin, and muscle were measured in an autograft control group. All animals in group I (n = 8) developed grade III clinical rejection by postoperative day 9. In group II (n = 9), the median onset of grade III rejection was postoperative day 40 (range, postoperative days 34 to 44). In group III (n = 6), two animals developed focal grade III rejection on postoperative days 35 and 56. The remaining four animals reached the 100-day endpoint without grade III rejection. In group IV, tacrolimus levels were low or undetectable in blood, whereas skin levels were 100-fold higher than underlying muscle. Topical tacrolimus therapy has the potential to prevent skin rejection in a composite tissue allograft. Preoperative depletion of T cells with antilymphocyte serum, along with a short course of systemic immunosuppression, prevents acute rejection, whereas topical tacrolimus inhibits immune cell function in the skin. Concentrations of tacrolimus are substantially higher in skin compared with underlying muscle and peripheral blood. Topical immunotherapy could reduce the morbidity associated with systemic immunosuppression in clinical composite tissue allografts.

On the Track of Mesothelial Progenitor Cells from the Peritoneal Cavity Transplanted to Immunodefficient Mice

Mesothelial progenitor cells have been reported to reside in either the monolayer of mesothelium, submesothelium or within the peritoneal cavity as free floating cells. As a putative plasticity has been reported for the mesothelial progenitor cells and considering the potential implications of the establishment of a novel resource of stem/progenitor cells in gene and cell therapeutics and tissue engineering, we conducted an in vivo tracking of transplanted mesothelial cells. In order to induce immunodeficiency, the recipient mice were treated with 32 mg kg(-1) of daily Cyclosporine. On days 14, 30 and 60 post transplantation, brain, heart, skeletal muscle and lung tissues were screened by a modified FISH method directed to the Y chromosome of donor cells. Fluorescence harboring cells were analyzed by flow cytometry and fluorescent microscopy. The data confirmed by PCR, demonstrated the existence morphology alteration of the donor cells in various organs of the recipient mice, notably in the skeletal muscle and lung and less in the heart and brain. Immunostaining of recovered cells from the nervous recipient tissues suggests differentiation of mesothelial cells in the new microenvironment.

Graft-versus-tumor effect following reduced-intensity allogeneic stem cell transplantation in prostate cancer

6551 Background: Allogeneic transplantation has been utilized as adoptive immunotherapy for patients with solid tumors resistant to conventional therapy. Methods: In 2001 we started a pilot study of allogeneic hematopoietic cell transplantation after a reduced-intensity regimen in patients with metastatic, androgen-independent prostate cancer, aged 18–70, ECOG PS 0–1. Planned sample size was 10 patients. Primary endpoint was feasibility of the procedure. The conditioning regimen included thiotepa, fludarabine, and cyclophosphamide. Patients received allogeneic peripheral blood cells from an HLA-identical sibling. A median of 6.9×10e6 CD34+ cells/kg were infused (range 4.8–11.8). Graft-versus-Host Disease (GvHD) prophylaxis consisted of cyclosporine A and short-course methotrexate. All the patients were evaluable for engraftment and chimerism. Results: Six patients have been enrolled. The median age was 61 years (range 51–66). The median time to reach an absolute neutrophil count of 1.0×10e9/l and a platelet count of 20×10e9/l was 11 and 12 days respectively (range 10–14 and 11–16). All patients achieved complete lymphoid- and myeloid-chimerism at day +90 by cytogenetics or by VNTR polymorphism analysis. Median day of cyclosporine A withdrawal was +85. Three patients developed acute GvHD grade ≥2, usually soon after cyclosporine withdrawal. At a median follow-up of 401 days (range 93–682), 2 patients are alive and 4 died, 2 for disease progression (+214 and +275), one for CMV disease (+93) and one for hemorrhagic cystitis (+527). This last patient achieved an almost complete response confirmed on choline-PET scan after cyclosporine withdrawal and limited chronic GvHD. In other 4 patients we observed a PSA reduction, concurrently with cyclosporine withdrawal or development of GvHD. Conclusions: The close association between GvHD and/or cyclosporine withdrawal and tumor responses strongly suggests that tumor regression was associated with an immune-mediated reaction related to allografting. Future strategies will aim at enhancing the anti-tumor effect and at decreasing GvHD and transplant-related mortality. No significant financial relationships to disclose.

Effects of Mycophenolate Mofetil on Cardiac Allograft Survival and Cardiac Allograft Vasculopathy in Miniature Swine

Chronic rejection, as manifested by cardiac allograft vasculopathy, remains the leading cause of late graft failure in heart transplant recipients. Despite recent clinical trials, the efficacy of mycophenolate mofetil in preventing human cardiac allograft vasculopathy remains controversial. We investigated whether mycophenolate mofetil would prevent cardiac allograft vasculopathy and prolong cardiac allograft survival in our well-established miniature swine model of heart transplantation. Hearts disparate at the major histocompatibility complex class I locus were heterotopically transplanted into miniature swine recipients treated with a 12-day course of mycophenolate mofetil (n = 3) or cyclosporine A (n = 3). Allograft survival, acute rejection, and chronic rejection were monitored in the two groups. Hearts transplanted with 12 days of cyclosporine were rejected between 46 and 61 days, whereas two of the three hearts transplanted with mycophenolate mofetil remained beating beyond 120 days (p = 0.02). At necropsy, there was a 4.9% mean prevalence of cardiac allograft vasculopathy in the mycophenolate mofetil group as compared with 16.6% in the cyclosporine group (p = 0.03). Cardiac allograft rejection and vasculopathy in the cyclosporine-treated group was associated with prominent myocardial interferon-gamma gene expression, a finding absent in two thirds of the mycophenolate mofetil-treated swine. Moreover, the mycophenolate mofetil-treated swine failed to develop IgM or IgG alloantibodies. A short course of mycophenolate mofetil resulted in a longer allograft survival than a similar course of cyclosporine. Moreover, mycophenolate mofetil reduced the prevalence of cardiac allograft vasculopathy as compared with cyclosporine-treated controls. The salutary effect of mycophenolate mofetil may be related to its ability to decrease interferon-gamma expression in the myocardium and prevent the generation of alloantibodies.

CD80/CD86 Costimulation Regulates Acute Vascular Rejection

Xenotransplantation may provide the only solution to the shortage of human donor organs. Although hyperacute rejection associated with xenotransplantation can now be overcome, acute vascular rejection (AVR) remains a primary barrier to xenotransplantation. To date, standard immunosuppressive agents fail to block AVR or prolong xenograft survival. The present study was undertaken to determine the role of CD80/CD86 costimulatory molecules in regulating AVR. Lewis rat hearts were transplanted heterotopically into wild-type or IL-12, CD80- or CD86-deficient C57BL/6 mice. Wild-type recipients were treated with CD80 or CD86 neutralizing Ab with and without daily cyclosporin A (CsA, 15 mg/kg). Transplanted hearts in untreated wild-type recipients were rejected on postoperative days (POD) 17-21 and showed cell-mediated rejection (CMR) and AVR pathologies. In contrast, transplanted hearts in IL-12 and CD80 recipients or wild-type recipients treated with CD80 neutralizing Ab were rapidly rejected on POD 5 and 6 with AVR pathology. Interestingly, hearts transplanted into CD86 knockout recipients or wild-type recipients treated with CD86 neutralizing Ab underwent CMR on POD 17. Finally, blockade of CD86 but not CD80 rendered xenograft recipients sensitive to daily CsA therapy, leading to indefinite xenograft survival. To conclude, we demonstrate that AVR can be overcome by blocking the CD86 costimulatory pathway. Furthermore, we demonstrate that CD80 and CD86 have opposing roles in regulation of xenotransplantation rejection, where CD80 drives CMR and attenuates AVR while CD86 drives AVR. Most strikingly, indefinite xenograft survival can be achieved by suppressing AVR with CD86 neutralization in combination of CsA therapy, which inhibits CMR.

Single Daily Dose Administration of Cyclosporine in Renal Transplant Recipients: A Preliminary Report

Introduction Cyclosporine microemulsion has been the mainstay immunosuppressive agent in renal transplantation for years. Since single daily dosing of cyclosporine is rarely used, the objective of this investigation was to evaluate the efficacy of a single daily dose versus twice daily dosing of cyclosporine in renal transplant recipients. Methods Retrospective evaluation of single-dose cyclosporine use was conducted for 15 renal transplant recipients for 12 months (study group). Equal numbers of matched renal transplant recipients were selected for age, sex, human leukocyte antigen mismatch, donor type, and immunosuppressive regimen (control group). Cyclosporine trough level and peak cyclosporine blood levels, 12-hour cyclosporine profile, and the area under the concentration-time curve were measured. Results There was a significant difference in cyclosporine peak blood level and calculated area under the curve after shifting to single-dose cyclosporine ( P = .001). In the study group, the mean area under the curve was significantly below the average therapeutic range before (3154 ng/mL/ho) versus 5532 ng/mL/h after shifting to the single-dose regimen (which was therapeutic). This value was 5749 ng/mL/h in the control group. Total daily cyclosporine dose was lower in the study group when compared with the control group at 6 and 12 months ( P = .01). There were significantly fewer adverse effects in patients in the study group than in patients in the control group. Conclusion We conclude that although cyclosporine dose should be individualized in renal transplant recipients, a single dose of cyclosporine has the added advantage of decreasing dosages and cyclosporine-related adverse effects while maintaining optimal graft function.

Combined Therapy of Prednisone and Cyclosporine as Treatment Option for Refractory Coeliac Disease and Clonal T Cell Receptor (TCR) Gene Rearrangement

Effective therapy of refractory coeliac disease is still under debate. The necessity for such treatment is underlined by the potential risk of the development of an enteropathy-associated T-cell lymphoma. We report of a male patient with coeliac disease first diagnosed in 1991. Under subsequent gluten-free diet, clinical symptoms of the disease necessitated only intermittent treatment with prednisone. A recent deterioration was treated with azathioprine which had to be stopped because of side effects. When we first saw the patient in August 2004, he had experienced a weight loss of 16 kg within 14 months and suffered from diarrhea, hypoalbuminia and impaired nutritional state. The diagnostic work-up (blood/stool/x-ray/CT) did not result in any other diagnoses explaining the clinical symptoms. GI endoscopy showed intraepithelial lymphocytosis, villous atrophy with crypt hyperplasia and ulcerative lesions in the small bowel. All biopsies (duodenum/jejunum/ileum/bone marrow/liver/lymph node) but not blood were characterized by monoclonal T-cell receptor-gamma gene rearrangement. Total parenteral nutrition resulted in a weight gain of 14 kg but administration of prednisone at different doses (20–60mg iv/die) was not associated with improved enteral resorption. Therefore, cyclosporine (initially 5mg/kg iv/die) was added to prednisone (60mg iv/die). Consequently, a stepwise reduction of parenteral nutrition was feasible. Within 4 months, the patient gained another 8 kg. A shift from parenteral to oral drug administration was successful under cyclosporine plasma levels between 65 and 96ng/ml (limitation of daily cyclosporine dosage to 2mg/kg because of developing renal insufficiency). The histological analysis of duodenal/jejunal biopsies did not show any change in the modified Marsh classification (IIIb). Conclusion: The combined administration of prednisone plus cyclosporine represents a clinically effective treatment option in patients with refractory celiac disease who are unresponsive to steroids alone and do not tolerate azathioprine.

Heart and en-bloc thymus transplantation in miniature swine

Donor-specific tolerance to organ allografts might be induced by cotransplantation of a sufficient amount of vascularized donor thymus. To facilitate donor thymus-induced cardiac allograft tolerance, we have developed a novel technique for heart and en-bloc thymus transplantation in swine. Donor heart and en-bloc thymus grafts were prepared by a technique that preserves the entire arterial supply and venous drainage of the right thymic lobe. En-bloc grafts (n = 4) were transplanted heterotopically into the abdomens of major histocompatibility complex-matched miniature swine. Recipients received 12 days of cyclosporine intravenously. Grafts were monitored by palpation, electrocardiographic monitoring, and periodic open biopsy. Engraftment of the donor thymus was demonstrated by measuring the proportion of recipient-type thymocytes in the donor thymus with flow cytometry. All of the heart and en-bloc thymus grafts had normal cardiac contractility and immediate perfusion of the thymus. All en-bloc grafts were accepted for more than 200 days without significant acute cellular rejection or cardiac allograft vasculopathy. Thymic tissue of en-bloc grafts displayed normal architecture and supported thymopoiesis of recipient-type cells. We have validated a new technique of donor thymus transplantation that could have utility in human heart transplantation.

Pharmacokinetic Advantages of Two-Hour Post-Dose Cyclosporin A Level for the Therapeutic Drug Monitoring in Stable Chinese Kidney Transplant Recipients

Background: Recent studies in Caucasian patients show that 2-hour post-dose cyclosporin A level (C2) monitoring has excellent correlation with the actual drug exposure and risk of rejection. However, the reliability of using C2 in stable Chinese renal transplant patients is unknown. Methods: Forty-nine stable Chinese renal transplant patients receiving microemulsion cyclosporin A (Neoral^®) as part of their immunosuppressive therapy were recruited. Area under the time-concentration curve (AUC) was determined from whole blood cyclosporin A level taken at 0, 1, 2, 4 and 6 h post-dose at time 0 month. Cyclosporin A levels were repeated at 0, 1 and 2 h post-dose at 1 and 2 months later to determine the intra-individual variation at these specific time points. Results: The average duration of transplantation was 77 ± 42 months, with average daily cyclosporin dosage of 200 ± 43 mg in two divided doses. AUC has excellent correlations with cyclosporin A level at 1 h (C1) and 2 h (C2) (r = 0.81 and 0.82 respectively, p < 0.001 for both). The correlation between AUC and trough cyclosporin A level (C0) was statistically significant but only modest (r = 0.52, p < 0.001). On the other hand, the intra-individual coefficient of variation (CV_w) of C1 was significantly larger than that of C2 (34.4 ± 24.2 vs. 15.9 ± 8.3%, p < 0.0001). Conclusion: We conclude that C2 level has favorable pharmacokinetic properties for therapeutic drug monitoring in stable Chinese transplant recipients. Both C1 and C2 have excellent correlation with AUC, but the intra-individual variability of C2 is much lower than that of C1.

Composite ‘Thymoheart’ Transplantation Improves Cardiac Allograft Survival

We have generated a novel composite organ, the thymoheart, which facilitates the contemporaneous transfer of fully vascularized and functional donor thymic tissue to the host at the time of cardiac transplantation. Composite thymoheart allografts were prepared in MHC-inbred miniature swine by implanting autologous thymic tissue into donor hearts 60–90 days before organ procurement. Thymoheart allografts and unmanipulated control hearts were then transplanted into three groups, each treated with the same 12 days of cyclosporine. MHC-matched thymohearts transplanted into euthymic recipients had a minimum survival ranging between 72 and 194 days vs. 42–64 days for unmanipulated control hearts (p = 0.02). MHC class I-disparate thymohearts transplanted into euthymic recipients had a minimum survival ranging between 64 and 191 days vs. 30–55 days for unmanipulated control hearts (p = 0.01). MHC class I-disparate thymohearts transplanted into thymectomized recipients survived between 41 and 70 days vs. 8–27 days for unmanipulated control hearts (p = 0.01). Cellular and humoral functional assays, and skin grafting, confirmed the presence of donor-specific hyporesponsiveness in long-term thymoheart allografts recipients. The transfer of vascularized, functional donor thymic tissue to the host at the time of cardiac transplantation may provide a novel approach to the induction of tolerance in human heart transplant recipients.

Induction of tolerance to heart transplants by simultaneous cotransplantation of donor kidneys may depend on a radiation-sensitive renal-cell population.

To determine the mechanism by which cotransplantation of a donor kidney and heart allograft induces tolerance to both organs in miniature swine, we examined the renal elements responsible for tolerance induction. Recipients received 12 days of cyclosporine, and transplants were performed across a major histocompatibility complex (MHC) class I mismatch. Group 1 animals received heart transplants (n=5); group 2 animals received heart and kidney allografts with no other manipulation (n=4); group 3 animals received heart transplants and donor-specific renal parenchymal cells (n=4); group 4 animals received heart and kidney allografts from lethally irradiated donors (n=7); group 5 animals received irradiated hearts and nonirradiated kidneys (n=2); group 6 animals received nonirradiated hearts and peripheral blood leukocytes from swine MHC matched to recipients and becoming tolerant to donor antigen (n=2); group 7 animals received nonirradiated hearts and donor-specific peripheral blood monocyte cells (PBMC) (n=2). Animals in group 1 developed vasculopathy and fulminant rejection by day 55. Animals in group 2 never developed vascular lesions. Parenchymal kidney cell infusion (group 3) did not prolong cardiac survival. Animals in group 4 developed arteriopathy by postoperative day (POD) 28. Group 5 recipients accepted allografts without vascular lesions. Adoptive transfer of leukocytes from tolerant swine (group 6) prolonged cardiac graft survival as much as 123 days, whereas donor PBMC infusion (group 7) did not affect cardiac survival or development of arteriopathy. Radiosensitive elements in kidney allograft may be responsible for tolerance induction and prevention of chronic vascular lesions in recipients of simultaneous heart and kidney allografts.

Correlation between daily cyclosporine dose and allograft injury in liver recipients with and without recurrent hepatitis C

Background: After liver transplantation, the daily cyclosporine dose is adjusted to maintain the blood level in a chosen range. The aim of this study was to assess the influence of liver graft injury on cyclosporine dose. Methods: The parameters of liver function were investigated in 145 patients. Ninety-two patients took part in a longitudinal study. Results: The cyclosporine dose correlated with the MEGX test ( r=0.38, P=0.01) and with the ICG ( r=0.38, P=0.0001) and BSP ( r=0.37, P=0.0002) clearances; it had an inverse correlation with transaminases (AST: r=0.38, P=0.0001) and histological lesions ( r=−0.29, P=0.005). The cyclosporine dose was lower in patients with recurrent hepatitis C (179±9 mg/day) than in those without (241±10 mg/day), and was lower in patients with chronic hepatitis (154±9 mg/day) than in those without (207±16 mg/day). In the longitudinal study, the percent variation of AST correlated inversely with that of cyclosporine dose ( r=−0.62, P=0.0002). Conclusion: Progressive graft injury leads to a reduction in the cyclosporine dose, particularly in patients with recurrent hepatitis C.

Thymoglobulin, sirolimus, and reduced-dose cyclosporine provides excellent rejection prophylaxis for pancreas transplantation.

We investigated a novel immunosuppressive protocol including thymoglobulin induction in combination with sirolimus and corticosteroids, followed by introduction of markedly reduced exposures to cyclosporine to prevent pancreas-transplant rejection. A 7-day course of thymoglobulin (1.5 mg/kg per day) was begun on postoperative day (POD) 0, together with 15 mg of sirolimus on POD 1, and followed by 5 mg per day, targeting these doses to achieve a trough of 10 to 20 ng/mL. When the serum creatinine was below 2.5 mg/dL, cyclosporine was introduced at 50 mg twice daily with dose adjustment to maintain a trough concentration of 100 to 125 ng/mL. The 18 patients included 14 simultaneous pancreas-kidney and 4 pancreas-after-kidney transplant recipients. Two patients were African-American, three patients had a pretransplant panel reactive antibody greater than 20%, and the human leukocyte antigen (HLA) mismatch was 4.5+/-1 (mean+/-standard deviation). With a mean follow-up of 13.6+/-4.7 months, patient, kidney, and pancreas graft survivals are 100%, 100%, and 94%, respectively. A single pancreas graft was lost to thrombosis. There were no acute rejection episodes and no opportunistic infections. Mean hospital stay was 9+/-3 days. At 3 months posttransplantation, the mean value of serum creatinine was 1.2+/-0.3 mg/dL, fasting glucose was 88+/-15 mg/dL, and sirolimus dose at month 3 was 6.3+/-3 mg per day and at month 12 2.7+/-1 mg per day. The average total daily cyclosporine A dose at month 3 was 208+/-62 mg per day and 133+/-13 mg per day at 1 year. This immunosuppressive regimen provided excellent prophylaxis against acute rejection with no opportunistic infections. We believe that careful monitoring of sirolimus and cyclosporine levels was critical to success of this protocol.

Split tolerance to a composite tissue allograft in a swine model.

The antigenicity of skin is a major obstacle to expanding human composite tissue transplantation. For example, multiple rejection episodes of the skin have been noted in clinical hand transplant patients. We have previously demonstrated tolerance to vascularized musculoskeletal allografts in major histocompatibility complex (MHC)-matched miniature swine treated with 12 days of cyclosporine. This regimen did not reproducibly lead to tolerance to subsequent frozen donor skin grafts. However, such skin grafts did not have a primary vascular supply. The aim of this study was to determine if tolerance to limb allografts with a vascularized skin component could be achieved with MHC matching and a 12-day course of immunosuppression. Hind limb grafts harvested with a 100 cm(2) cutaneous paddle were transplanted heterotopically into six MHC-matched, minor antigen-mismatched miniature swine. All animals received a 12-day course of cyclosporine. One control animal was not immunosuppressed. Grafts were evaluated with biweekly biopsies and tissue viability determined by histologic analysis. To test for sensitization, frozen donor skin grafts were applied to all animals that survived to postoperative day 100. All treated animals (n=6) were tolerant to their musculoskeletal allografts at the time of necropsy (>100 days) regardless of the status of the epidermis. One animal demonstrated tolerance to the skin for more than 180 days. The other five animals demonstrated prolonged survival of the epidermal portion of the graft. The control animal rejected the graft epidermis at 10 days postoperatively. Frozen donor skin grafts demonstrated accelerated rejection (<10 days) in three of the animals and led to simultaneous rejection of both the epidermis of the allograft and the skin graft in the long-term tolerant animal. The rejection of the skin grafts did not break tolerance to the musculoskeletal portion in any of the animals. All animals exhibited indefinite survival of the musculoskeletal portion of their allografts but only prolonged survival of the epidermis. The loss of the graft skin appears to be the result of an isolated immune reaction to the skin, and, in particular, the epidermis. This observation is further substantiated by the accelerated rejection of secondarily placed frozen donor skin grafts.

Cyclosporine and long-term kidney graft survival.

Previous analysis of kidney transplant data from the Collaborative Transplant Study database showed that patients receiving cyclosporine 3-6 mg/kg/day 1 year posttransplantation had the best graft survival rate 7 years posttransplantation. Longer-term and additional analyses have now been performed. Data from cadaver kidney transplants performed between 1985 and 1998 were analyzed retrospectively. Patients were included if they had a functioning graft 1 year posttransplantation, and the daily cyclosporine dose administered 1 year posttransplantation was reported. Data on cyclosporine dose, serum creatinine concentration, and systolic blood pressure were recorded 1 and 5 years after transplantation; information on graft survival was documented at yearly intervals. Patients receiving cyclosporine 3-6 mg/kg/day 1 year posttransplantation had the best graft survival rate 10 years posttransplantation. Cyclosporine <2 mg/kg/day was least beneficial overall and in subanalyses based on age, risk level, and 1-year serum creatinine concentration. The microemulsion cyclosporine formulation (Neoral) was associated with a significantly higher 4-year graft survival rate than the conventional formulation (Sandimmune; P=0.0001). Median systolic blood pressure 5 years posttransplantation was similar in each 1-year cyclosporine dose category (range of medians 139.0-140.0 mmHg). The percentages of patients with serum creatinine concentrations of <130, 130-260, 260-400, or >400 micromol/L 1 and 5 years posttransplantation were similar across 1-year cyclosporine dose categories, with the exception of >6 mg/kg/day, where there was a shift toward a less favorable serum creatinine concentration over time. The 1-year cyclosporine dose was significantly associated with long-term graft survival, with evidence of underimmunosuppression at doses <3 mg/kg/day and overimmunosuppression at doses >6 mg/kg/day, but had little influence on systolic blood pressure or serum creatinine concentration at doses up to 6 mg/kg/day.

Tolerance to limb tissue allografts between swine matched for major histocompatibility complex antigens.

Transplantation of limb tissue allografts would greatly expand the realm of reconstructive surgery. However, the toxicity of chronic immunosuppression has adversely tilted the risk-benefit balance for clinical transplant. In this study, a procedure was sought to achieve host tolerance to limb tissue allografts through matching of the major histocompatibility complex (MHC) antigens between donor and host swine using only a 12-day course of cyclosporine. Massachusetts General Hospital (MGH) miniature swine were used as a large animal model with defined MHC, and musculoskeletal grafts from the donor hind limb were transplanted heterotopically to the recipient femoral vessels. Allografts from MHC-mismatched donors treated with cyclosporine (n = 4) were rejected in less than 6 weeks by gross inspection and histologic sections. Allografts from MHC-matched, minor antigen mismatched donors not treated with cyclosporine (n = 4) were rejected between 9 and 12 weeks. Allografts from similarly matched donors treated with 12 days of cyclosporine (n = 7) showed no evidence of rejection until sacrifice between 25 and 47 weeks. Thus allograft tolerance was achieved between MHC-matched swine using a limited course of cyclosporine. Demonstration of limb tissue allograft survival in a large animal model without long-term immunosuppression represents an important step toward clinical transplantation.

Bone density loss after allogeneic hematopoietic stem cell transplantation: a prospective study.

The incidence and course of bone density abnormalities following hematopoietic stem cell transplantation are poorly understood and complicated by the impact of multiple factors. Hip, spine, and wrist bone mineral densities (BMDs) were measured in 104 adults (54 women, 54 men; mean age, 40 years [range, 18-64 years]) at 3 and 12 months after allogeneic transplantation. Clinical and laboratory variables were evaluated using univariate and multivariate analyses to determine risk factors for osteoporosis, fracture, and avascular necrosis. At 3 months posttransplantation, combined (male and female) hip, spine, and wrist z scores were -0.35, -0.42, and +0.04 standard deviations, respectively. At 12 months both men and women experienced significant loss of hip BMD (4.2%, P < .0001); changes in the spine and wrist were minimal. The cumulative dose and number of days of glucocorticoid therapy and the number of days of cyclosporine or tacrolimus therapy showed significant associations with loss of BMD; age, total body irradiation, diagnosis, and donor type did not. Nontraumatic fractures occurred in 10.6% of patients and avascular necrosis in 9.6% within 3 years posttransplantation. The decrease in height between pretransplantation and 12 months posttransplantation was significant (P = .0001). Results indicate that loss of BMD after allogeneic stem cell transplantation is common and accelerated by the length of immunosuppressive therapy and cumulative dose of glucocorticoid. An increased incidence of fracture and avascular necrosis may adversely impact long-term quality of life. Prevention of bone demineralization appears warranted after stem cell transplantation.

Mechanisms of tolerance induction in the heart/kidney model in miniature swine

Purpose: We have previously shown that cotransplantation of a kidney and heart into a class I disparate recipient treated with 12 days of cyclosporine (CyA) induced tolerance to both organs and prevented chronic rejection. In contrast, isolated heart transplantation resulted in cardiac allograft vasculopathy (CAV) and rejection by POD 55. This study investigated the mechanisms whereby kidney cotransplantation induced tolerance in this pre-clinical, large animal model.

The effects of mycophenolate mofetil on cardiac allograft survival and cardiac allograft vasculopathy in miniature swine

Background. Chronic rejection, as manifested by cardiac allograft vasculopathy, remains the leading cause of late graft failure in heart transplant recipients. Despite recent clinical trials, the efficacy of mycophenolate mofetil in preventing human cardiac allograft vasculopathy remains controversial. We investigated whether mycophenolate mofetil would prevent cardiac allograft vasculopathy and prolong cardiac allograft survival in our well-established miniature swine model of heart transplantation. Methods. Hearts disparate at the major histocompatibility complex class I locus were heterotopically transplanted into miniature swine recipients treated with a 12-day course of mycophenolate mofetil (n 3) or cyclosporine A (n 3). Allograft survival, acute rejection, and chronic rejection were monitored in the two groups. Results. Hearts transplanted with 12 days of cyclosporine were rejected between 46 and 61 days, whereas two of the three hearts transplanted with mycophenolate mofetil remained beating beyond 120 days (p 0.02). At necropsy, there was a 4.9% mean prevalence of cardiac allograft vasculopathy in the mycophenolate mofetil group as compared with 16.6% in the cyclosporine group (p 0.03). Cardiac allograft rejection and vasculopathy in the cyclosporine-treated group was associated with prominent myocardial interferon- gene expression, a finding absent in two thirds of the mycophenolate mofetil-treated swine. Moreover, the mycophenolate mofetil-treated swine failed to develop IgM or IgG alloantibodies. Conclusions. A short course of mycophenolate mofetil resulted in a longer allograft survival than a similar course of cyclosporine. Moreover, mycophenolate mofetil reduced the prevalence of cardiac allograft vasculopathy as compared with cyclosporine-treated controls. The salutary effect of mycophenolate mofetil may be related to its ability to decrease interferon- expression in the myocardium and prevent the generation of alloantibodies. (Ann Thorac Surg 2005;80:1787‐93) © 2005 by The Society of Thoracic Surgeons