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W Mark

Publications and source records attributed to W Mark.

At least 19 recordsLinked to original sources

Infectious complications following 72 consecutive enteric-drained pancreas transplants.

New immunosuppressive protocols and advanced surgical technique resulted in an improved outcome of pancreatic transplantation (PTx) with infection remaining the most common complication. Seventy-two enteric-drained whole PTxs performed at the Innsbruck University Hospital between September 2002 and October 2004 were retrospectively analyzed. Prophylactic immunosuppression consisted of either the standard protocol consisting of single bolus antithymocyteglobulin (ATG) (Thymoglobulin, Sangstat or ATG Fresenius) induction (9 mg/kg), tacrolimus (TAC), mycophenylate mofetil (MMF) and steroids (38 patients) or a 4-day course of ATG (4 mg/kg) tacrolimus and steroids with MMF (n = 19), or Sirolimus (n = 15). Perioperative antimicrobial prophylaxis consisted of Piperacillin/Tazobactam (4.5 g q 8 h) in combination with ciprofloxacin (200 mg q 12 h) and fluconazole (400 mg daily). Ganciclovir was used for cytomegalovirus (CMV) prophylaxis if donor was positive and recipient-negative. Patient, pancreas, and kidney graft survival at 1 year were 97.2%, 88.8%, and 93%, respectively, with no difference between the groups. All retransplants (n = 8) and single transplants (n = 8) as well as all type II diabetics and nine of 11 patients older 55 years received standard immunosuppression (IS). The rejection rate was 14% and infection rate 46% with no difference in terms of incidence or type according to the three groups. Severe infectious complications included intra-abdominal infection (n = 12), wound infection (n = 7), sepsis (n = 13), respiratory tract infection (n = 4), urinary tract infection (n = 12), herpes simplex/human herpes virus 6 infection (n = 5), CMV infection/disease (n = 7), post-transplant lymphoproliferative disorder (PTLD, n = 3), invasive filamentous fungal infection (n = 4), Clostridial/Rotavirus colitis (n = 1), and endocarditis (n = 1). All four patients in this series died of infectious complications (invasive aspergillosis n = 2) (one with Candida glabrata superinfection), invasive zygomycosis (n = 1), PTLD (n = 1). Five grafts were lost (vascular thrombosis n = 3, pancreatitis n = 1, noncompliance n = 1). Infection represented the most frequent complication in this series and all four deaths were of infectious origin. Better prophylaxis and management of infections now should be the primary target to be addressed in the field of pancreas transplantation.

Adult↗

Status 5 years after bilateral hand transplantation.

Graft survival and function early after hand transplantation is good. It remains unknown, however, whether long-term survival is limited by chronic rejection. We here describe the clinical course and the status 5 years after bilateral hand transplantation with emphasis on immunosuppression (IS), function, morphology and graft vascular changes. Clinical observation, evaluation of hand function, skin biopsies, X-ray, ultrasound, angiography, CT angiography, electrophysiologic studies including compound motor and sensory action potentials (CMAP, CSAP) and somatosensory evoked potentials were performed and results recorded at regular intervals. Following reduction of IS one mild (grade II) rejection episode occurred at 4 years. Subsequently, skin histology remained normal and without signs of chronic rejection. Hand function continuously improved during the first 3 years and remained stable with minor improvement thereafter. CMAP and CSAP progressively increased during the observation period. Latencies of the cortical responses were prolonged but amplitudes were within normal range. Investigation of hand vessels revealed no signs of occlusion but showed revascularization of a primarily occluded right radialis artery. Motor and sensory function improved profoundly between years 1 and 5 after hand transplantation. No signs whatsoever of chronic rejection have been observed.

Angiography↗

Tetrahydrobiopterin attenuates microvascular reperfusion injury following murine pancreas transplantation.

In this study we investigated the effect of tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthases, on ischemia-reperfusion injury (IRI) following murine pancreas transplantation. Pancreatic grafts were exposed to prolonged cold ischemia times (CIT) and different treatment regimens: normal saline (S), S + 16 h CIT, BH4 50 mg/kg + 16 h CIT. Nontransplanted animals served as controls. Graft microcirculation was analyzed by means of functional capillary density (FCD) and capillary diameters (CD) after 2 h reperfusion using intravital microscopy. Quantification of inflammatory responses (mononuclear infiltration) and endothelial disintegration (edema formation) was done by histology (hematoxylin and eosin), and peroxynitrite formation assessed by nitrotyrosine immunostaining. FCD was significantly reduced after prolonged CIT, paralleled by increased peroxynitrite formation as compared with controls (all p < 0.05). Microcirculatory changes correlated significantly with intragraft peroxynitrite generation (Spearman: r = -0.56; p < 0.01). Pancreatic grafts treated with BH4 displayed markedly higher FCD values (p < 0.01) and abrogated nitrotyrosine staining (p = 0.03). CD were not significantly different in any group. Histology showed increased inflammation, interstitial edema, hemorrhage, acinar vacuolization and focal areas of necrosis after 16 h CIT, which was diminished by BH4 administration (p < 0.01). BH4 treatment significantly reduces post-ischemic deterioration of microcirculation as well as histologic damage and might be a promising novel strategy in attenuating IRI following pancreas transplantation.

Animals↗

Excellent results with calcineurin inhibitor-free initial immunosuppression in old recipients of old kidneys.

The ever increasing demand for donor organs has forced transplant surgeons to liberalize selection criteria. To avoid initial nephrotoxicity to kidneys from donors over 65 years of age, immunosuppression was begun with an IL-2 receptor antibody, mycophenolate mofetil, and steroids in a total of 38 recipients over 65 years. Calcineurin inhibitors (CI) were added after sufficient graft function was reached. After a mean cold ischemia time of 14:01 hours and a delayed function rate of 31%, patient survival, graft survival, and serum creatinine were 97.4%, 94.7%, and 1.5 mg/dL at 1 and 92.1%, 92.1%, and 1.7 mg/dL at 2 years, respectively. Thus, excellent results can be achieved in old recipients of old donor kidneys with CI-free initial immunosuppression.

Adrenal Cortex Hormones↗

Infectious complications limit the outcome of liver transplantation in medical urgency code 2 patients.

The Organ shortage has caused an accumulation of acutely decompensated patients listed as medical urgency code 2 (MUC 2) (United network for Organ Sharing 2) while awaiting liver transplantation. Between June 1997 and June 2003, 22 of 360 liver transplantation patients (6%) were listed as MUC 2. Prophylactic immunosuppression consisted of calcineurin inhibitor-based drug therapy, using antithymocyte globulin or interleukin-2 receptor antagonist induction in 64%. The overall perioperative infection rate was 50%, and the rejection rate was 23%. We observed 7 episodes of oral or genital herpes simplex virus lesions; 2 patients (both with cytomegalovirus-mismatched transplants) developed cytomegalovirus disease, and another 5 patients received ganciclovir for preemptive therapy or prophylaxis. Two patients developed pneumonia: 5, sepsis that originated in 4 cases from a contaminated central venous line; and 1 methicillin-resistant endocarditis, which resulted in Staphylococcus aureus lethal outcome. After a median follow up of 3 years, 1 patient underwent a repeat transplantation procedure and 6 patients had died, 4 of them from infectious complications. Liver transplantation of MUC 2-listed patients may result in acceptable results similar to those of MUC 3 and MUC 4 categories.

Adult↗

Impact of steroid withdrawal on metabolic parameters in a series of 112 enteric/systemic-drained pancreatic transplants.

BACKGROUND: New immunosuppressive protocols and advanced surgical techniques have brought major improvements in pancreas transplantation outcomes. Steroid withdrawal might have a beneficial long-term effect on metabolic parameters. METHODS: We retrospectively analyzed 112 enteric-drained pancreas transplants (PTx) performed between March 1997 and October 2001. Prophylactic imunosuppression consisted of ATG induction, tacrolimus, MMF, and steroids. RESULTS: Actuarial patient, pancreas, and kidney graft survivals at 1 year were 96.4%, 86.7%, and 95.3%, respectively. The 5-year pancreatic graft survival was 77%. In addition to four patients who died with functioning grafts, eight grafts were lost due to intraabdominal infection; ten due to rejection; and the remaining three, due to other complications. One-year follow-up was available for 89 patients, Including 22 (25%) withdrawn from steroids. Significantly lower median serum cholesterol values were measured among patients off steroids (158 mg/dL [range 135 to 231 mg/dL] versus 188 mg/dL [range 91 to 278 mg/dl]; P = .005). In contrast, the difference in triglycerides did not reach statistical significance; that is, at last follow-up, at a median of 41.3 months posttransplant, 64 patients (70% of the available study population) were off steroids. Cessation of steroids resulted in significantly lower cholesterol (median 176 mg/dL [range 101 to 229 mg/dL] versus 196 mg/dL [range 107 to 339 mg/dL]; P = .047) and triglyceride values (median 74 mg/dL [range 34 to 299 mg/dL] versus 98 mg/dL [range 47 to 565 mg/dL]; P = .008), but had no impact on rejection rate, serum creatinine and urea, HbA(1c), or fasting blood glucose levels. CONCLUSIONS: Steroid withdrawal after pancreatic transplantation can be performed in the majority of cases without risking an immunologic complication, but it seems to be associated also with the benefit of improved lipid metabolism.

Adult↗

Kaposi sarcoma in solid organ transplant recipients: a single center report.

BACKGROUND: Human herpes virus (HHV8) is associated with Castleman's disease, primary effusion lymphoma, and the Kaposi's sarcoma (KS). PATIENTS AND METHODS: Among 3815 solid organ transplants performed at our center between 1977 and 2003, five patients (0.1%) were identified with KS. RESULTS: There were one cardiac, one liver, and three renal allograft recipients of median age of 52 (range 38 to 60) years, three of whom were females. Three patients were of Italian and one of Turkish descent; only one patient was a native Austrian. The onset of the disease was 2.0, 7.5, 7.8, 9.4 months, and 22 years posttransplant. Diagnosis of KS was based in all cases on histology. The heart recipient developed a tumor on the planta pedis; one renal recipient, on both legs. The liver and the two remaining renal recipients presented with disseminated disease. Treatment in all cases consisted of reduction in immunosuppression, together with surgery (n = 1), chemotherapy (n = 1), or irradiation (n = 2). Furthermore, immunosuppression was switched in two cases from Tacrolimus to Sirolimus. In the liver recipient a complete response was achieved; he died, however, due to noncompliance followed by graft failure. One renal recipient died without evidence of recurrent disease from myocardial infarction. The cardiac and two renal recipients are alive between 4 months and 17 years with well-functioning grafts and no evidence of recurrent disease. DISCUSSION: HHV8-associated lesions seem to be extremely rare in the Central European transplant population. Nevertheless, awareness of KS is important for early diagnosis and optimal treatment.

Adult↗

Four consecutive renal transplantations in a patient with adenine phosphoribosyltransferase deficiency.

We report a patient with complete adenine phosphoribosyltransferase deficiency and urolithiasis, in whom 4 consecutive cadaveric renal transplantations were performed; 2,8-dihydroxyadenine crystal nephropathy recurred within weeks in the first and second graft when the patient was not treated with allopurinol immediately after transplantation. In the third graft, recurrence of disease could be prevented by immediate allopurinol treatment. This graft was lost due to chronic allograft nephropathy without significant crystal deposition. After a fourth transplantation, again without initial allopurinol, the disease recurred following an initial vascular rejection. Addition of allopurinol significantly improved renal function of the 2nd and 4th graft. This case indicates that outcome of renal transplantation in patients with adenine phosphoribosyltransferase deficiency critically depends on immediate postoperative pharmacotherapy with allopurinol, which is able to prevent 2,8-dihydroxyadenine nephropathy in the graft. Furthermore, rapid recurrence of disease without allopurinol seems to be triggered by delayed graft function and acute rejection.

Adenine Phosphoribosyltransferase↗

Improved technique for infrahepatic vena cava reconstruction in guinea pig-to-rat liver transplantation.

Guinea pig-to-rat orthotopic liver transplantation is associated with serious technical problems contributing to impaired graft perfusion and primary graft failure. In order to shorten the procurement procedure and thereby minimize liver damage before flushing, a simplified technique for infrahepatic caval reconstruction was developed. Dissection of the infrahepatic vena cava (IHVC) from adrenal glands and renal and lumbar veins represents the most difficult and time-consuming part of the donor operation, which is often not well tolerated by the animal; we avoided this step by using an isogeneic vena cava interposition graft (VCIG) following in situ perfusion. This graft is connected with the IHVC transsected just below the liver with a cuff technique. Donor operations lasted 15 to 20 minutes with the new technique (n = 7) compared to 52 to 76 minutes with conventional technique (n = 7). Reduced operating time was associated with markedly improved graft perfusion and significantly better graft survival. This modification of the donor procedure for the guinea pig-to-rat liver xenograft using a VCIG significantly reduces operating time and improves reperfusion and recipient survival.

Anastomosis, Surgical↗

Incidence of intraabdominal infection in a consecutive series of 40 enteric-drained pancreas transplants with FK506 and MMF immunosuppression.

Although the introduction of FK506 and MMF has markedly improved patient and graft outcome after pancreas transplantation, this procedure is still associated with a high surgical complication rate. The aim of the following study was to retrospectively analyze a series of 40 consecutive pancreas transplants with enteric drainage with regard to intraabdominal infection (IAI). Between March 1997 and December 1998 a total of 40 whole pancreas transplants were performed. Prophylactic immunosuppression consisted of an intraoperative single shot ATG (Thymoglobulin), FK506, MMF, and prednisone. The mean observation period was 14.6 (5-26) months. Overall incidence of IAI was 27.5% (n = 11) leading to pancreatectomy in 5 patients (12.5%). In the remaining 6 patients the graft could be rescued by necrosectomy and radical drainage of the abscess (5 patients) or percutaneous drainage (1 patient). Pancreatectomy or local infection did not alter kidney graft function in the 11 patients with simultaneous pancreas kidney transplantation. In 10 patients no evidence for leakage at the site of enteric anastomosis was present, one duodenal leak occurred due to ischemia. IAI in the early postoperative period was the predominat risk factor for graft loss. An early and invasive diagnostic approach is recommended to maximize the chance of graft rescue.

Adult↗

Transient complement inhibition plus T-cell immunosuppression induces long-term survival of mouse-to-rat cardiac xenografts.

BACKGROUND: The use of anti-B-cell and T-cell immunosuppressive agents leads to only a few weeks' survival of mouse-to-rat cardiac xenografts. METHODS: BALB/c cardiac xenografts were transplanted to Lewis rats treated with cyclosporine (CsA) and/or cobra venom factor (CVF). RESULTS: CsA alone did not prolong xenograft survival (2.2+/-0.4 days), whereas CVF alone led to minimal prolongation of survival (5.6+/-0.8 days) as compared with nontreated recipients (2.4+/-0.5 days). The combination of CsA plus CVF, the latter given for either 2 days or 11 days, resulted in long-term survival of 14/16 hearts (> 100 days). Production of IgM elicited xenoreactive antibodies (EXA) peaked on day 4 after transplantation and decreased thereafter. Production of IgG EXA occurred only in the control group, whereas, in the CsA/CVF-treated group, IgG EXA were totally suppressed. Long-term surviving grafts showed (i) excellent preservation of morphology and minimal leukocyte infiltration, (ii) deposition of IgM, IgG and weak C3 deposition on the graft endothelium, (iii) low level infiltration by rat macrophages, (iv) replacement of mouse dendritic cells by class II+ rat macrophages, and (v) expression within endothelial and smooth muscle cells, macrophages, and myocytes of HO-1, a "protective gene" not seen in the rejected hearts. CONCLUSIONS: Our present findings suggest that long-term mouse-to-rat cardiac xenograft survival is induced by temporary suppression of C activation and sustained T-cell suppression leading to inhibition of IgG EXA production. Florid expression of a protective gene (HO-1) may contribute to survival.

Animals↗

2-Chlorodeoxyadenosine (cladribine) in combination with low-dose cyclosporin prevents rejection after allogeneic heart and liver transplantation in the rat.

The purine analogue 2-chlorodeoxyadenosine (2-CDA) has been shown to possess synergistic immunosuppressive properties when given together with cyclosporin (CSA) in a rat small bowel transplant model. The present study investigated the immunosuppressive potency of 2-CDA alone and in combination after liver or heart transplantation in a fully allogeneic rat model with 5 animals in each group. Immunosuppression was provided with CSA 10 mg/kg body weight (BW)/day orally or 2-CDA 0.1 mg/kg/BW day intravenously or both compounds together in the dosages mentioned. Animals were sacrificed on day 10 following transplantation, and graft histology was assessed. In addition, cardiac graft function was evaluated by palpation immediately prior to sacrificing the animal. CSA given alone was able to mitigate but not prevent rejection. 2-CDA alone did not exhibit any detectable immunosuppressive effect. When CSA was combined with 2-CDA, no rejection was seen in 80% of the liver allografts and in 60% of heart allografts, and only mild rejection was observed in the remaining animals. All hearts of the combined treatment group, however, beat strongly. From these findings it is concluded that 2-CDA alone has no, but together with CSA a strong immunosuppressive effect in preventing solid organ allograft rejection.

Animals↗

[A new method of orthotopic liver transplantation from the guinea pig to the rat].

Guinea pig to rat orthotopic liver transplantation is associated with serious technical problems contributing to impaired graft reperfusion and a high incidence of primary non function. In order to reduce the operation time and thereby organ damage during procurement a simplified technique for reconstruction of the infrahepatic vena cava was developed and is described in detail. Reduced operation time was associated with markedly improved lobular graft perfusion and significantly better graft survival. We suggest a modification of the donor operation for the guinea pig to rat xenograft liver model for the sake of reducing non immunological factors in this difficult setting.

Animals↗

At what stage does pancreas allograft rejection become irreversible?: an experimental study.

BACKGROUND: It is commonly believed that abnormal blood glucose levels indicate irreversible rejection. We were interested in determining the stage at which rejection remains reversible. METHODS: A total of 54 Lewis rats were rendered diabetic with 55 mg/kg streptozocin and were then given a pancreas transplant from Brown Norway donors. Pancreatic juice was collected in a subcutaneous reservoir. All recipients received 15 mg/kg cyclosporine A (CsA) for 5 days. CsA was then discontinued for 2 days (n=7, group 1), 4 days (n=7, group 2), 6 days (n=9, group 3), 8 days (n=9, group 4), 9 days (n=11, group 5), and 10 days (n=11, group 6). Two animals of each group were euthanized at the end of the immunosuppressive-free interval, for histological assessment of the grade of rejection (G0, GI, GII, GIII). Rejection was treated with methylprednisolone (7 mg/kg body weight) and CsA (15 mg/kg body weight). The volume of pancreatic juice, together with juice cytology (C0, CI, CII) and blood glucose levels, was assessed daily. RESULTS: Blood glucose remained normal throughout the observation period in animals with GI and GII rejection. The numbers of animals that became diabetic were as follows: 5 of 9 (group 4), 7 of 11 (group 5), and 8 of 11 (group 6). Decreased amounts of pancreatic juice were observed in all animals, except those in group 1. The histology returned to normal after anti-rejection therapy in four animals (57%) of group 1, in two animals (28%) of group 2, and in one animal (11%) of groups 3 and 4, respectively. Although there was no animal in groups 5 and 6 with normal graft histology after treatment, there were still four (36%) and three (27%) animals, respectively, that were normoglycemic and that had pancreatic grafts with well-preserved islets. CONCLUSIONS: From these data, we conclude that even GIII rejection with severe endothelialitis and isleitis can be reversed. Therefore, we suggest that a trial of enhanced immunosuppression is justified in patients with advanced pancreas allograft rejection.

Animals↗

Accommodation of vascularized xenografts: expression of "protective genes" by donor endothelial cells in a host Th2 cytokine environment.

Organ xenografts under certain circumstances survive in the presence of anti-graft antibodies and complement, a situation referred to as "accommodation." We find that the endothelial cells (ECs) in hamster hearts that accommodate themselves in rats express genes, such as A20 and bcl-2, that in vitro protect ECs from apoptosis and prevent upregulation in those cells of proinflammatory genes such as cytokines, procoagulant and adhesion molecules. Hearts that are rejected do not express these genes. In addition, vessels of rejected hearts show florid transplant arteriosclerosis whereas those of accommodated hearts do not. Accommodated xenografts have an ongoing T helper cell type 2 (Th2) cytokine immune response, whereas the rejected grafts have a Th1 response. We propose a model for factors that contribute to the survival of xenografts and the avoidance of transplant arteriosclerosis.

Animals↗

Immunomodulatory effects of the alkaloid sinomenine in the high responder ACI-to-Lewis cardiac allograft model.

Extracts of the plant Sinomenium acutum have been used safely since ancient times in Chinese medicine for treatment of rheumatic diseases, and the purified alkaloid, sinomenine, was recently shown to have anti-inflammatory and antirheumatic effects. This study describes the effects of sinomenine in the high responder ACI-->Lewis cardiac transplant model in which allograft rejection occurred at 5 days posttransplant. Treatment with sinomenine (15-30 mg/kg/day i.p.) or a subtherapeutic dose of cyclosporine (CsA, 1.5 mg/kg/day, i.m.) prolonged allograft survival only marginally (mean survival of 5.4 and 7.8 days, respectively). In contrast, the combination of sinomenine and CsA had a statistically significant synergistic effect, with a mean survival of 42.2 days (P < 0.001). Allografts harvested at day 5 from recipients treated with either sinomenine or CsA showed dense mononuclear cell infiltrates with widespread subepicardial infarcts, edema, and microvascular platelet and fibrin deposition. Immunohistologic analysis showed that intragraft leukocytes consisted of >75% macrophages with approximately 10-20% T cells and <5% B or NK cells. Mononuclear cell activation was shown by expression of IL-2R (CD25, 10-20%) and labeling for IL-2 (approximately 10%), and IFN-gamma (10-20%), as well as TNF-alpha (>50%) and iNOS (>50%), but only low levels of IL-4 or IL-10 (<5%). Intragraft endothelial cells were activated, as shown by upregulation of MHC class II antigen and ICAM-1 (CD54) compared with only basal levels in normal donors hearts. Combined sinomenine/CsA therapy significantly enhanced graft morphology, resulting in only mild mononuclear cell infiltration, and an absence of infarcts, platelets, or fibrin deposition. Though residual intragraft mononuclear cells at day 5, as in control grafts, consisted primarily of macrophages plus small numbers of IL-2R+ T cells, these cells lacked expression of IL-2, had only low levels of IFN-gamma, but showed dense labeling for IL-4 and IL-10. In addition, TNF-alpha and iNOS were reduced to basal levels and no endothelial cell activation was observed, despite high titers of endothelium-bound IgM, IgG, and C3. Mitogen-induced in vitro proliferation of rat thymocytes was also more effectively decreased by the sinomenine/CsA combination than by either agent alone. These studies demonstrate the therapeutic value of sinomenine in transplantation, and indicate that this agent has novel and interesting antimacrophage, T cell, and endothelial effects that warrant further evaluation.

Adjuvants, Immunologic↗