Strength and pain measures associated with lateral epicondylitis bracing

BACKGROUND: In the experiment described here, we investigated the effects of the immunosuppressants FK506 and leflunomide (Lef) on the survival of hamster hearts and liver xenografts in Lewis rats. METHODS: Lewis rats were used as recipients of hamster heart or liver grafts using different regimens of FK506 and Lef. Donor-matched heart grafts were transplanted into long-term surviving Lewis rat recipients of hamster xenografts to test donor-specific prolongation of xenograft survival. Hyperimmune, late xenograft rejection, and naive sera were transferred into long-term surviving Lewis rat recipients of hamster heart xenografts to determine whether these sera could inhibit the efficacy of donor-specific long-term survival. Anti-donor-specific antibodies were analyzed by flow cytometry. RESULTS: After a short induction with FK506 plus Lef, maintenance treatment with FK506 alone was sufficient to prolong survival of hamster xenografts. All hamster heart and four of six hamster liver xenografts survived for more than 3 months. Second hamster hearts were permanently accepted by Lewis rats bearing long-term surviving hamster heart xenografts when rats were treated with FK506 monotherapy (mean survival time >60 days, n=4). Long-term surviving hamster heart grafts were rejected after transfer of hyperimmune serum but not late xenograft rejection serum or naive serum. Lef and FK506 significantly reduced the production of anti-donor-specific antibodies in Lewis rats transplanted with hamster liver and heart xenografts. CONCLUSION: Long-term survival of hamster liver and heart xenografts in Lewis rats could be induced by a regimen of short-term FK506 in combination with Lef followed by FK506 monotherapy. The acquired sensitivity of late xenoreactivity to FK506 reflects primarily a modification in the host immune response to the hamster graft.     

Severe and complicated malaria. Report of six cases

The major obstacle for successful xenotransplantation of islets to large animals and human diabetics is the host rejection. To address the rejection problem, we studied the efficacy of UV-B irradiation, cryopreservation and immunosuppression on the in vivo functional time and immunogenicity of adult porcine islets (PI) in outbred CD1 mice. Exposure of PI to UV-B irradiation between 300-1800J/M2 did not affect the cellular viability as assessed by fluorescein diacetate or their daily insulin secretion in vitro. Fresh PI normalized the blood glucose (BG) of diabetic CD1 mice for 3.1+/-0.6 (n = 8, mean+/-SEM) days. Islets treated with 600J/M2 UV-B irradiation or cryopreservation had similar graft functional times to fresh islets upon transplantation in diabetic CD1 mice. Immunosuppression with cyclosporin A (CsA), antilymphocyte serum (ALS) and FK506 prolonged the functional time of fresh pig islets to 7.9+/-0.9 (n = 9), 6.2+/-1.3 (n = 5) and 24.2+/-10.4 (n = 12) days, respectively. However, additional pretransplant treatment with either UV-B irradiation or cryopreservation did not further increase the functional time of pig islets in mice immunosuppressed with CsA. Furthermore, there was no apparent difference in the frequency of appearance of cytotoxic antibodies and antibody titers in the recipients of UV-B irradiated or cryopreserved pig islet compared with non-treated islets. The UV-B irradiation and cryopreservation of PI before transplantation with the present protocols did not appear to have significant effect on the islet immunogenicity when assessed by in vivo survival duration and anti-donor antibody titer production.     

Limb allograft in rats: studies on optimal maintenance dose of FK506 and development of graft-versus-host-disease (GVHD)

The optimal dose of FK506 on rat limb allograft was investigated across the BN-to-F344 histocompatibility barrier. BN limb allografts were rejected in untreated F344 hosts within 11 +/- 1 days (mean +/- SD) after operation. A single injection of 0.5 mg/kg, 1.0 mg/kg, or 2.0 mg/kg of FK506 on the day of transplantation significantly prolonged graft survival, mean survival times (MST) based on gross sign of skin rejection were 16 +/- 1 days, 19 +/- 1 days, 21 +/- 1 days, respectively. Maintenance doses of 0, 0.25, 0.5, 1.0, or 2.0 mg/kg/week of FK506 after a single administration of 10 mg/kg of FK506 on the day of limb allograft prolonged the graft survival, 63 +/- 10, 68 +/- 20, 87 +/- 23, 98 +/- 30, 136 +/- 20 days, respectively, and showed no evidence of infection or toxic side effects. The regimen of lower maintenance dose of FK506, however, developed chronic GVHD. In the second set of experiments, development of peripheral blood chimeras was studied in PVG-to-ACl limb allograft model. A single injection of 50 mg/kg of the day of transplantation prolonged graft survival and MST was 154 days. The average rates of peripheral blood chimeras were 2 to 6% and there was no relationship between graft survival and peripheral blood chimeras. However, GVHD developed in one of the six recipients at 201 days after operation. In the similar experiments, grafts were irradiated before operation. Peripheral blood chimeras was not observed in there experiments and GVHD was not developed in 300 days after operation. These data suggest that FK506 is quite effective for rat limb allograft survival in dose-dependent manner and GVHD could be prevented by graft irradiation before operation.     

Retrospective estimation of exposure to benzene in a leukaemia case-control study of petroleum marketing and distribution workers in the United Kingdom

FK506 (tacrolimus), a potent immunosuppressant, is used for inhibiting allograft rejection in the organ transplantation field. In a preclinical toxicity study in rats, FK506 induced various toxicities, including renal and pancreatic injuries. One of these toxic findings was cataract, and we have found that cataract appeared in rats dosed orally with FK506 for 13 weeks and more. Therefore, to better elucidate the onset mechanism of FK506-induced cataract, we measured biochemical parameters, such as sorbitol, Na,K-ATPase and glutathione in the lens of rats. Rats were dosed with FK506 in oral daily doses of 0.2, 1 or 5 mg/kg for 13 weeks, the lowest dose of which approximated the expected clinical dosage. Cataract developed in the 5-mg/kg/day group, with an incidence of 25%, whereas no cataract formation was observed in the 0.2- or 1-mg/kg/day groups. Five mg/kg/day led an increase of sorbitol and a decrease of reduced type glutathione, but did not affect Na,K-ATPase activity of the lens. FK506 is known to have diabetogenicity mediated through pancreatic injury, which appears as vacuolation of islet cell in rats. Five mg/kg/day of FK506 induced an elevation of blood glucose associated with glucose intolerance, and decrease of both basal insulin level and insulin content in the pancreas, and the changes were in parallel with the cataract development in the present study. On the other hand, diabetic parameters did not change in the 0.2- or 1-mg/kg/day groups. These observation suggest that diabetes developed in the rats dosed with 5 mg/kg/day of FK506. Coadministration of a novel aldose reductase inhibitor, Zenarestat, at an oral dose of 50 mg/kg/day resulted in a reduction of incidence of the FK506-induced cataract and a decrease of sorbitol levels in the lens when compared to that in the lens of rats dosed with 5 mg/kg/day of FK506. These results suggest that FK506-induced cataract in rats is due to an accumulation of sorbitol in the lens, secondary to the diabetogenic effect of FK506. FK506 treatment at the doses of 0.2 and 1 mg/kg/day neither affected parameters indicative of diabetes nor induced cataract in rats, suggesting that the cataract would not develop with FK506 if diabetic parameters were kept under control.     

Effect of chronic anesthesia on the drug-metabolizing enzyme system and heme pathway regulation

Inadequate vascularization and microvascular rejection are major limitations for successful free pancreatic islet xenotransplantation. Commonly used immunosuppressive regimens may alter the process of vascularization, and are ineffective at preventing graft rejection. In this study, we investigated, in vivo, the action of the new immunosuppressive agent RS-61443 on angiogenesis and microvascular rejection of rat pancreatic islets after xenogeneic transplantation into the dorsal skinfold of Syrian golden hamsters. In nontreated xenografts, intravital fluorescence microscopy demonstrated a regular process of vascularization during the first 6 days after transplantation. On days 10, 14, and 20, graft rejection was observed, characterized by microvascular leukocyte accumulation (244+/-59 mm(-2)), loss of endothelial integrity, and capillary perfusion failure. Islet xenografts of animals treated with RS-61443 (40 mg/kg per day) demonstrated inhibition of vascularization with the consequence of a markedly reduced size of the grafts' microvascular network (0.05+/-0.007 mm2), when compared with that of nontreated xenografts (0.09+/-0.015 mm2; P< 0.05). However, treatment with RS-61443 effectively prevented microvascular graft rejection, as indicated by the absence of leukocyte accumulation (24+/-9 mm(-2); P<0.01), endothelial damage, and nutritive perfusion failure. Thus, RS-61443 treatment may represent an interesting approach for improving the outcome of pancreatic islet xenotransplantation.     

The enhanced immunosuppressive efficacy of newly developed liposomal FK506 in canine liver transplantation

Local delivery of immunosuppressants to the graft and lymphatic tissue is a potential appraoch to enhance the immunosuppressive efficacy and to alleviate systemic adverse effects simultaneously. By taking advantage of this method, we developed liposomal FK506. Previous pharmacokinetic study of liposomal FK506 indicated increased FK506 levels in the liver and spleen. Because the liver is the site of the allograft in liver transplantation and the spleen is a major lymphoid tissue, we hypothesized that liposomal FK506 would increase immunosuppressive efficacy in liver transplantation. We evaluated this hypothesis in a canine model. Orthotopic liver transplantation was performed using beagle dogs, and the recipients were divided into the following groups: group I, no immunosuppression (n = 5); group II, 0.05 mg/kg/day of FK506 i.v. in a commercially available i.v. formulation for 14 days (n = 5); and group III, 0.05 mg/kg/day of FK506 i.v. in a liposomal formulation for 14 days (n = 5). All recipients in group I died within 2 weeks. Recipients in group II died within 33 days. In contrast, three recipients in group III survived for more than 200 days (P < 0.05 versus group I or group II). In DNA analysis, splenocyte proliferation activity in group III was significantly suppressed in comparison with group II. These results suggest that liposomal FK506 markedly increase the immunosuppressive efficacy of FK506 in liver transplantation. A local immunosuppressive effect in the grafted liver and significant suppression of splenocyte proliferation might contribute to enhancement of the immunosuppressive efficacy of liposomal FK506.     

Quantitative immunohistochemical changes in the endocrine pancreas of nonobese diabetic (NOD) mice

Two-centimeter nerve allografts were transplanted across a major histocompatibility barrier from donor ACI rats into a 0.5-cm gap in the sciatic nerve of recipient Lewis rats and immunosuppressed with FK506, 2 mg/kg per day for 3 months. One group of animals continued to receive intermittent immunosuppression with FK506, 2 mg/kg twice a week for another 2 months, whereas the second group of animals received no further immunosuppression in order to determine whether rejection of nerve allografts can still occur after immunosuppression is withdrawn, even after the axons have regenerated through the nerve graft. The sciatic function index improved from -76.3 at 3 months to -46.6 at 5 months in those animals continuing to receive intermittent immunosuppression, but only improved to -66.8 at 5 months when immunosuppression was discontinued. Similarly, somatosensory evoked potentials demonstrated an improvement in relative latency from 2.3 msec at 3 months to 0.34 msec at 5 months in animals continuing to receive intermittent immunosuppression, but only improved to 1.29 msec at 5 months when immunosuppression was discontinued. Nerve allografts continuing to receive intermittent immunosuppression showed no signs of rejection by light or electron microscopy and no significant difference compared with isografts, whereas nerve allografts whose immunosuppression had been stopped at 3 months showed mild signs of rejection, less regeneration, and a smaller number of nerve fibers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Isolation of islands of Langerhans from human and porcine pancreas for transplantation to humans

The enormous variability of donor factors and organ procurement related variables prevent a constant isolation success, thus reducing the potential number of clinical islet transplants. Since the availability of intact and viable pancreatic donor tissue intended for islet transplantation is limited, the porcine pancreas was selected as a potential source of xenogeneic islets for human recipients. The differences of islet histomorphology between porcine and human pancreas result in a higher intrinsic fragility of porcine islets during collagenase digestion. Nevertheless, if the isolation method is modified to inhibit factors potentially toxic to pig islets, reproducibility of isolation success is higher in the pig as in the human due to a lower variability in donor characteristics and the opportunity of preselection in regard to age and race. If xenograft rejection can be overcome and the risk of xenosis can be minimized, the logistic prerequisites for xenotransplantation of large amounts of viable pig islets into human recipients with insulin dependent diabetes are fulfilled.     

Critical islet mass for successful porcine islet autotransplantation

A major reason for the failure of clinical islet transplantations may be a limited islet mass. The aim of this study was to determine the critical islet mass necessary for normalization of glucose metabolism in a porcine model. Diabetes was induced by total pancreatectomy. The splenic lobe of the pancreas was intraductally distended with UW-solution containing 2.67-3.33 mg/ml collagenase, and the distended pancreas was digested in a continuous digestion filtration device. The islets were purified on a isoosmotic Ficoll-sodium-diatrizoate gradient. The survival period of the diabetic recipients in group 2 and 3 receiving, respectively, a low (2.14+/-0.39 microL/kg body weight) and a high (4.99+/-0.83 microL/kg body weight) islet mass was significantly prolonged compared to that of diabetic recipients in group 1 receiving no islet transplantation. However, the survival period of the recipients in group 2 was not significantly different to that in group 3. Three recipients of an islet mass of >5 microl/kg body weight became normoglycemic (fasting blood glucose <100 mg/dl) for more than two months. Furthermore, the glucose and insulin release reactions to the glucose challenge were comparable to that before pancreatectomy. Contrarily, another five diabetic recipients of an islet mass of <4 microL/kg body weight became a fasting blood glucose level of <200 mg/dl. The glucose and insulin release reactions to the glucose challenge were improved only, but not normalized compared to that before pancreatectomy. The data presented in this study demonstrate that metabolic normalization in pancreatectomized diabetic minipigs can be established by autotransplantation of an islet mass of >5 microl/kg body weight.     

Improving results of pediatric renal transplantation

BACKGROUND: Outcome after renal transplantation in children has been variable. We undertook a retrospective study of our experience over the past five years. STUDY DESIGN: From January 1, 1988, to October 15, 1992, 60 renal transplantations were performed upon 59 children at the Children's Hospital of Pittsburgh. Twenty-eight (47 percent) of the kidneys were from cadaveric donors, and 32 (53 percent) were from living donors. The recipients ranged in age from 0.8 to 17.4 years, with a mean of 9.8 +/- 4.8 years. Forty-six (77 percent) recipients were undergoing a first transplant, while 14 (23 percent) received a second or third transplant. Eight (13 percent) of the patients were sensitized, with a panel reactive antibody of more than 40 percent. Eleven of the 14 patients undergoing retransplantation and seven of the eight patients who were sensitized received kidneys from cadaveric donors. Thirty-three (55 percent) patients received cyclosporine-based immunosuppression, and 27 (45 percent) received FK506 as the primary immunosuppressive agent. RESULTS: The median follow-up period was 36 months, with a range of six to 63 months. The one- and four-year actuarial patient survival rate was 100 and 98 percent. The one- and four-year actuarial graft survival rate was 98 and 83 percent. For living donor recipients, the one- and four-year actuarial patient survival rate was 100 and 100 percent; for cadaveric recipients, it was 100 and 96 percent. Corresponding one- and four-year actuarial graft survival rates were 100 and 95 percent for the living donor recipients and 96 and 69 percent for the cadaveric recipients. Patients on cyclosporine had a one- and four-year patient survival rate of 100 and 97 percent, and patients on FK506 had a one- and three-year patient survival rate of 100 and 100 percent. Corresponding one- and four-year actuarial graft survival rates were 100 and 85 percent in the cyclosporine group, while one- and three-year actuarial graft survival rates were 96 and 84 percent in the FK506 group. The mean serum creatinine level was 1.24 +/- 0.64 mg per dL; the blood urea nitrogen level was 26 +/- 13 mg per dL. The incidence of rejection was 47 percent; 75 percent of the rejections were steroid-responsive. The incidence of cytomegalovirus was 10 percent. The incidence of post-transplant lymphoproliferative disorder was 8 percent. None of the patients on cyclosporine were able to be taken off prednisone; 56 percent of the patients receiving FK506 were taken off prednisone successfully. Early growth and development data suggest that the patients receiving FK506 off prednisone had significant gains in growth. CONCLUSIONS: These results support the idea that renal transplantation is a successful therapy for end-stage renal disease in children. They also illustrate the potential benefits of a new immunosuppressive agent, FK506.     

FK 506 'rescue' immunosuppression for obliterative bronchiolitis after lung transplantation

PRELIMINARY EXPERIENCE: In a consecutive case series (level V evidence) involving 10 recipients of unilateral lung transplantation (LT) with bronchiolitis obliterans, in conjunction with Fujisawa protocol 93-0-003, the physiologic responses to FK 506 (tacrolimus) "rescue" immunosuppression were assessed. Recipients were 22+/-18 months post-LT and demonstrated progressive allograft dysfunction that was refractory to pulsed-dose methylprednisolone therapy. All recipients received induction immunosuppression with Minnesota antilymphocyte globulin (10 to 15 mg/kg/d) for 5 to 10 days, cyclosporine (CsA) (whole-blood Abbott TDX fluorescence polarization immunoassay (Abbott Inc, Abbott Park, IL)=600 to 800 ng/mL), azathioprine (2 mg/kg/d), and prednisone (tapered to 0.2 mg/kg/d). The "rescue" regimen consisted of oral FK 506 adjusted to maintain a whole-blood Abbott IMX microparticle enzyme immunoassay (Abbott Inc, Abbott Park, IL) of 10 to 15 ng/mL with an initial increase in prednisone (1.0 mg/kg/d) during conversion that was subsequently tapered to 0.2 mg/kg/d. Spirometry was performed monthly in accordance with accepted American Thoracic Society criteria. Recipients were classified in accordance with the International Society for Heart and Lung Transplantation (ISHLT) "Working Formulation for Standardization of Nomenclature and for Clinical Staging of Chronic Dysfunction in Lung Allografts" as stages Ib (n=2), IIb (n=4), and IIIb (n=4) upon entry to the protocol. The deltaFEV1/month relationships during CsA- and FK 506-based regimens were analyzed by linear regression and compared by signed rank test (p<0.05). RESULTS: The deltaFEV1/month slopes were -0.0687+/-0.0221 and +0.0300+/-0.033 L/mo (mean+/-SEM) for CsA and FK 506, respectively (p=0.037). Although no significant spirometric improvement was noted in most recipients, no further decline in FEV1 occurred after conversion to FK 506. Recipients with less severe chronic dysfunction (ie, obliterative bronchiolitis [OB] stages Ib and IIb) stabilized their spirometric indexes at higher levels. Two recipients with OB stage IIIb died of hypercapnic respiratory failure at 6 and 8 months after conversion. CONCLUSIONS: The deltaFEV1/mo slopes stabilized after FK 506 conversion. Earlier conversion may be beneficial in stabilizing FEV1 at a higher plateau. Significant economic impact may be anticipated with FK 506 compared to alternative cytolytic strategies for OB. However, multicenter prospective controlled investigations are necessary to further address the potential role of FK 506 after LT (level I evidence). Furthermore, the ISHLT "Staging of OB Syndrome" may have significant clinical implications vis-à-vis prognosis and potential therapies.     

Effects of FK506 on experimental membranous glomerulonephritis induced by cationized bovine serum albumin in rats

BACKGROUND: There have been no reports on the effect of FK5 06, a new immunosuppressive agent, on experimental membranous glomerulonephritis (MN) induced by an exogenous antigen. Therefore we investigated the effects of FK506 on MN induced by cationized bovine serum albumin (C-BSA) in rats. METHODS: Two weeks after the rats were immunized with 1 mg of C-BSA and Freund's complete adjuvant, they received intravenous injections of 3 mg/kg of C-BSA 3 times weekly for 4 weeks. Rats were divided into four groups: group A (n = 5) received intramuscular injections of 3 mg/kg of FK506 daily for 5 days beginning 2 days before the first immunization; group B (n =4) received 1 mg/kg of FK506 daily for 2 weeks beginning 2 weeks after the first immunization; and group C (n =4) received 1 mg/kg of FK506 daily for 2 weeks beginning 4 weeks after the first immunization. Group D (n = 5) received no FK506 and served as the control group. Rats were sacrificed 8 weeks after the first immunization. RESULTS: Administration of FK506 in the preimmunization stage almost completely suppressed the development of MN in group A. Histological findings in groups B and C were similar to those in group D, the control group. However, urinary protein excretion was significantly lower in group B (24+/-46 mg/day) and C (220+/-44 mg/day) than in group D (330+/-61 mg/day). Expression of intracellular adhesion molecule-1 in glomeruli and the number of leukocyte functioning-associated molecules-1 were significantly decreased in groups A, B, and C compared with the control group. Administration of FK506 was not associated with any significant side-effects or histological abnormalities. The whole-blood trough levels of FK506 in groups B and C were 9.1 ng/ml and 9.2 ng/ml respectively. CONCLUSIONS: The efficacy of FK506 was significantly increased when the drug was administered in the early phase of immunization in this model. The present study suggests that FK506 may be useful in patients with intractable nephrotic syndrome such as MN.     

Isolation of the pig islets of Langerhans: evaluation of in vitro and in vivo function

Pig islets are considered the best alternative to human islets in the treatment of insulin-dependent diabetes. Pigs could represent a potential islet donor for xenotransplantation in humans because of the close similarity between human and porcine insulin and the theoretically unlimited availability of porcine pancreas. From November 1991 to January 1997 we performed 221 pig islet isolations from 3 pig sources: group 1: minipigs (age 9-18 months) and white pigs (3-8 months), group 2: large white pigs (5-8 months), group 3: large white pigs (12-24 months). Islets were isolated according to a semi-automated method using enzymatic digestion and purification through discontinuous Euro-Ficoll gradients. The pancreases were surgically removed in our laboratory for group 1, while pancreases from groups 2 and 3 were removed at the slaughterhouse with an average warm ischemia time of 15 minutes. In vitro islet function was assessed by static incubations and perifusions, and in vivo islet function by transplantation under the kidney capsule of nude diabetic mice. The results were as follows: [table: see text] Insulin secretion increased twofold after in vitro glucose stimulation. We obtained restoration of euglycemia in diabetic mice which survived > 3 months after the graft and returned to diabetes after nephrectomy. This study shows that our isolated pig islets are viable and functional in vitro and in vivo after transplantation.     

Marked prolongation of rat skin xenografts induced by intrathymic injection of xenogeneic splenocytes and a short course of rapamycin in antilymphocyte serum-treated mice

The effect of intrathymic (IT) injection of donor splenocytes and a short course of rapamycin (Rapa) treatment on rat to mouse skin xenograft survival was investigated. ACI rat skin xenografts were transplanted to (C57BL/6 x A)F1 mice treated with rabbit anti-mouse lymphocyte serum (ALS) on days -1, +2, and +4 relative to skin grafting on day 0. Fifty million donor-type splenocytes were injected intrathymically on day 7 after transplantation. Rapa was given intraperitoneally every other day from day 0 to day 12 at a dose of 3.0 mg/kg. Prolonged skin xenograft survival was observed in ALS- and Rapa-treated recipients (no IT injection) with a median survival time of 47 days. However, skin graft survival was markedly more prolonged in the group treated with ALS, Rapa, and IT injection of donor splenocytes did not have a beneficial effect on skin xenograft survival in ALS-treated recipients. An increased presence of donor-type cells was observed in the thymus of the ALS- and Rapa-treated recipients for 7 days after IT injection of donor splenocytes. In conclusion, a short course of Rapa markedly augments rat skin xenograft survival in ALS-treated mice injected intrathymically with donor-type splenocytes.     

Effect of a novel immunosuppressant, FK 506, on autoimmune glomerulonephritis in Brown Norway rats

Mercuric-chloride (HgCl2) induces a lymphoproliferative disorder and autoimmune glomerulonephritis in Brown Norway rats. The effects of a new immunosuppressant FK 506 on this model of glomerulonephritis were studied. Brown Norway rats were treated with HgCl2 according to a standard protocol (HgCl2 1 mg/kg s.c. 3 times/ week). Rats developed proteinuria at day 7, which reached a plateau level at day 14. On day 14, renal histology showed prominent mesangial cellular proliferation and the expansion of mesangial matrix. Electron microscopic study showed the effacement of visceral epithelial foot processes and the microvillous transformation of the visceral epithelium. Immunofluorescence study showed a strong linear staining for IgG and the adhesion molecule ICAM-1 in all glomeruli. Coadministration of FK 506 (1 mg/kg s.c. daily) prevented the appearance of proteinuria at day 14 (621.4 +/- 30.5 vs. 2.2 +/- 2.7 mg/day) and the morphological lesions. These findings suggest that FK 506 could be useful for the therapy of certain types of human glomerulonephritis.     

Posttransplant nonfunction of canine islets in PVG rats deficient in complement component C6

BACKGROUND: Discordant islet xenografts are immediately nonfunctional in nonimmunosuppressed recipients other than the mouse, a process called primary nonfunction. Although at present it is unknown whether complement is involved, complement might participate in the induction of primary nonfunction through a number of mechanisms. We investigated the potential role of the membrane attack complex of complement in primary nonfunction of transplanted xenoislets. METHODS: Canine islets were transplanted into both nonimmunosuppressed and immunosuppressed normocomplementemic and C6-deficient (C6D) PVG rats. Cyclosporine, rapamycin, deoxyspergualin, and mycophenolate mofetil were used for immunosuppression from day -3 to cessation of islet cell function. Serum glucose was measured at 6 hr after transplant and daily thereafter. Xenograft tissue sections were obtained at various times after transplant and stained for inflammatory cells and insulin. RESULTS: Canine islets grafted in nonimmunosuppressed C6D rats and normocomplementemic rats underwent primary nonfunction in all animals. The incidence of primary nonfunction in animals receiving a four-drug immunosuppressive regimen was 33% in the normocomplementemic rats but only 10% in the C6D rats. The mean functional islet survival time was 1.57+/-0.33 days in the normocomplementemic group and 2.70+/-0.67 days in the C6D group (P=0.38). The islet xenografts showed little difference in degree and composition of cell infiltration between normocomplementemic and C6D rats. CONCLUSION: The membrane attack complex does not appear to play a major role in primary nonfunction of canine islet xenografts in nonimmunosuppressed PVG rats. However, there was a lower incidence of primary nonfunction and a longer posttransplant survival time in immunosuppressed C6D rats, suggesting the membrane attack complex may play a minor role in recipients that are heavily immunosuppressed.     

FK 506 and mycophenolate mofetil in renal transplant recipients: six-month results of a multicenter, randomized dose ranging trial. FK 506 MMF Dose-Ranging Kidney Transplant Study Group

The effective dose of MMF with FK 506 has not been previously studied in a prospective, randomized, controlled setting. In the present study, we evaluated two different daily doses of MMF (1 and 2 g) and compared it to the historically conventional therapy of AZA. At 6 months post-transplant, we found no significant difference in the incidence of acute rejection between the AZA group and the MMF 1 g group. However, patients who started on MMF 2 g/d had significantly delayed and lower incidence of acute rejection as compared to the other two groups. We found that patients who were initiated on MMF 2 g frequently had their dose lowered, primarily for gastrointestinal or hematologic symptoms; by 6 months after-transplant, patients in the MMF 2 g group had a mean dose of 1.5 g. It is unclear from this study if initiating patients on MMF 1.5 g in combination with FK 506 would be as effective as initiating a patient on MMF 2 g. Further studies of the combination of FK 506 and MMF in kidney transplant recipients to further define the optimal dosing regimen are warranted. In summary, the combination of FK 506 and MMF is well-tolerated, safe, and effective in cadaveric kidney transplant recipients.     

A new rat infection-heart transplant model: effect of infection on graft survival studies

Considerable progress has been made in survival rates of heart transplant recipients; however, infections continue to be a major cause of death after transplantation. Although infection itself appears to cause immunologic suppression in some nontransplantation studies, the lack of an infection-transplant animal model has limited further investigation of this observation. We evaluated the utility of a heterotopic rat infection heart-transplant model by studying the effect of infection and limited administration of two immunosuppressive agents, cyclosporine and FK506, on allograft rejection and survival. Lewis rats received ACI heart allografts, and intraperitoneal infection was induced by cecal ligation. Infection was confirmed by blood and ascitic fluid cultures. Results showed that graft survival was slightly, but significantly, higher (p < 0.05) in group II (transplantation with infection) when compared to the control group I (transplantation only). Histologic rejection scores were less (p < 0.05) in group II 6 days after transplantation. The second phase of the study compared the effect of infection after transplantation in rats given a 1-week course of cyclosporine or FK506, which were discontinued after the induction of infection. Although the cyclosporine group had prolonged survival when compared to the FK506 group (p < 0.05), the respective infection groups receiving immunosuppression revealed no significant difference in allograft survival or histologic rejection scores when compared to the control groups. In this preliminary study, infection without immunosuppression resulted in a slight, but statistically significant, increase in allograft survival and reduced acute cellular rejection. In those groups receiving immunosuppressive agents, no additive immunosuppressive effect was attributable to bacterial infection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characteristics of corneal xenograft rejection in a discordant species combination

PURPOSE: To characterize the fate of Lewis rat corneas transplanted to Hartley guinea pigs. METHODS: Full-thickness Lewis rat corneal buttons were grafted orthotopically to Hartley guinea pigs (xenografts), ACI rats (allografts), or Lewis rats (isografts). Two panels of recipients were presensitized with xenogeneic skin grafts or allogeneic skin grafts. Serum samples were collected pre- and post-transplant and analyzed by flow cytometry and indirect immunofluorescence. RESULTS: Unlike vascularized xenografts that reject within 30 min, corneal xenografts had a mean survival time of 8 days. Presensitization with guinea pig skin grafts increased recipient IgM and IgG xenoantibody levels, as measured by flow cytometry on guinea pig hematopoietic cells, and significantly accelerated corneal xenograft rejection with a mean survival time of 5 days. Presensitization with allogeneic ACI skin grafts had no effect on xenoantibody levels or xenogeneic corneal graft survival. Guinea pig corneas stained by indirect immunofluorescence with normal rat serum exhibited low (1+) but significant binding of IgG and IgM, primarily on epithelium and stroma. Serum from Lewis rats that rejected a corneal xenograft had elevated IgG and IgM xenoantibodies that reacted strongly (4+) with guinea pig cornea and heart. CONCLUSIONS: In the discordant guinea pig-to-rat species combination, donor corneas express xenoantigens; rejection of corneal xenografts stimulates IgM and IgG xenoantibody production; sensitization to xenoantigens can accelerate corneal xenograft rejection; and discordant corneal xenografts, unlike vascularized organs, are not hyperacutely rejected.