Initial in vivo experience of pig artery patch transplantation in baboons using mutant MHC (CIITA-DN) pigs.

BACKGROUND: In the pig-to-nonimmunosuppressed baboon artery patch model, a graft from an α1,3-galactosyltransferase gene-knockout pig transgenic for human CD46 (GTKO/CD46) induces a significant adaptive immune response (elicited anti-pig antibody response, increase in T cell proliferation on MLR, cellular infiltration of the graft), which is effectively prevented by anti-CD154mAb-based therapy. METHODS: As anti-CD154mAb is currently not clinically applicable, we evaluated whether it could be replaced by CD28/B7 pathway blockade or by blockade of both pathways (using belatacept + anti-CD40mAb [2C10R4]). We further investigated whether a patch from a GTKO/CD46 pig with a mutant human MHC class II transactivator (CIITA-DN) gene would allow reduction in the immunosuppressive therapy administered. RESULTS: When grafts from GTKO/CD46 pigs were transplanted with blockade of both pathways, a minimal or insignificant adaptive response was documented. When a GTKO/CD46/CIITA-DN graft was transplanted, but no immunosuppressive therapy was administered, a marked adaptive response was documented. In the presence of CD28/B7 pathway blockade (abatacept or belatacept), there was a weak adaptive response that was diminished when compared with that to a GTKO/CD46 graft. Blockade of both pathways prevented an adaptive response. CONCLUSION: Although expression of the mutant MHC CIITA-DN gene was associated with a reduced adaptive immune response when immunosuppressive therapy was inadequate, when blockade of both the CD40/CD154 and CD28/B7 pathways was present, the response even to a GTKO/CD46 graft was suppressed. This was confirmed after GTKO/CD46 heart transplantation in baboons.

Predictive value of the Charlson comorbidity index in kidney transplantation.

BACKGROUND: Nonimmunologic factors have been recently implicated in worse outcomes after kidney transplantation, producing a need to predict the operative risk among kidney recipients. We assessed the predictive value of the Charlson comorbidity index (CCI) among kidney transplant recipients. METHODS: A retrospective study of 223 first deceased-donor kidney transplantations performed from 2000 to 2007 evaluated the role of comorbidities. RESULTS: About 50% of recipients displayed >1 comorbid condition before transplantation; the most frequently reported was diabetes mellitus. Increasing CCI scores significantly affected graft and patient survivals. Crude analysis showed a significant association between CCI >1 and risk of death (hazard ratio [HR], 3.87; 95% confidence interval [CI], 1.06-14.06; P = .04). After adjustment for several covariates, high CCI values remained significantly predictive of posttransplantation outcomes with a HR for death of (12.53; 95% CI, 1.9-82.68; P = .009). CONCLUSIONS: Our predictive model showed a strong association of CCI and patient survival even after adjustment for several clinical covariates. CCI may be used to evaluate patients referred for kidney transplantation who display a significant burden of comorbid conditions that increase the risk of premature death or graft loss.

Delayed graft function and long-term outcome in kidney transplantation.

BACKGROUND: There are still many controversies about the impact of delayed graft function (DGF) on kidney transplantation outcome. The aims of this study were to define factors associated with DGF and to ascertain the relative impact of DGF on kidney transplantation outcome, both in the early postoperative period and in long-term follow-up. PATIENTS AND METHODS: Four hundred kidney transplant recipients were reviewed to assess the clinical impact of DGF on long-term outcome. RESULTS: The overall prevalence of DGF was 24.3%. DGF was significantly associated with increasing recipient and donor age, duration of dialysis, and cold ischemia time. Patients with DGF displayed a significantly worse graft (P = .005) and patient (P < .001) survival compared with recipients with immediate function. CONCLUSION: DGF is a frequent complication of renal transplantation and may be associated with a reduced graft and even patient survival. Strategies to prevent graft injury and, more specifically, DGF may be an important clue to provide a better long-term outcome in kidney transplantation.

Quality of life in kidney transplantation from marginal donors.

OBJECTIVE: Enhancement of the subjective components, recognition of overall needs, and careful consideration of subjectively perceived quality of life among dialysis and/or transplanted patients appear to be key objectives to promote optimized adherence to treatment and active cooperation of the patient. This study explores the relationship between self-rated health among recipients of kidney transplantations from deceased marginal donors (age older than 55 years) in relation to gender, age, time on dialysis, years after transplantation, and donor age. PATIENTS AND METHODS: Posttransplant quality of life was assessed with the Complete Form Health Survey (SF-36) in 70 recipients of kidney transplantations from marginal deceased donors. RESULTS: Donor age did not negatively influence health status perceived by the subjects. The vitality and mental health seemed to increase with greater donor ages, but the status of perceived health, vitality, social activities, and mental health were negatively influenced by the age of the transplant. CONCLUSIONS: Our study shows that good general health and social well-functioning can be achieved also among recipients of organs from older donors. Thus, age alone should not be a barrier to organ donation, providing that the organ function is normal and that specific disease is absent in the organ.

Kidney transplantation from hepatitis B virus core antibody-positive donors: prophylaxis with hepatitis B immunoglobulin.

OBJECTIVE: Hepatitis B virus core antibody (HBcAb)-positive organ donors have the potential to transmit infection to transplant recipients. PATIENTS AND METHODS: We investigated the use of a single dose of 2000 IU of hepatitis B immunoglobulin in 18 patients among a population of 54 kidney transplant recipients from HBcAb-positive deceased donors. RESULTS: Twelve recipients were HBcAb-positive before transplantation. Among the other 42 patients, 5 (11.9%) seroconverted from HBcAb-negative to HBcAb-positive, whereas one HBcAb-positive recipient became hepatitis B virus surface antigen-positive with clinical signs of active hepatitis 6 years after transplantation. In the 18 patients who underwent prophylaxis, we did not find any seroconversion or hepatitis B virus (HBV) transmission. Graft and patient survival of HBcAb-positive kidney transplants did not differ significantly with a matched population of HBcAb-negative transplantation. CONCLUSION: These results suggest that kidney transplantation from HBcAb-positive donors is safe with a low rate of HBV transmission. A prophylaxis with a single shot of hepatitis B immunoglobulin may be effective in reducing the risk of HBV seroconversion or reactivation and may be suggested in all naïve or HBcAb-positive transplant recipients.

Technical aspects of unilateral dual kidney transplantation from expanded criteria donors: experience of 100 patients.

One option for using organs from donors with a suboptimal nephron mass, e.g. expanded criteria donors (ECD) kidneys, is dual kidney transplantation (DKT). In adult recipients, DKT can be carried out by several techniques, but the unilateral placement of both kidneys (UDKT) offers the advantages of single surgical access and shorter operating time. One hundred UDKT were performed using kidneys from ECD donors with a mean age of 72 years (Group 1). The technique consists of transplanting both kidneys extraperitoneally in the same iliac fossa. The results were compared with a cohort of single kidney transplants (SKT) performed with the same selection criteria in the same study period (Group 2, n = 73). Ninety-five percent of UDKTs were positioned in the right iliac fossa, lengthening the right renal vein with an inferior vena cava patch. In 69% of cases, all anastomoses were to the external iliac vessels end-to-side. Surgical complications were comparable in both groups. At 3-year follow-up, patient and graft survival rates were 95.6 and 90.9% in Group 1, respectively. UDKT can be carried out with comparable surgical complication rates as SKT, leaving the contralateral iliac fossa untouched and giving elderly recipients a better chance of receiving a transplant, with optimal results up to 3-years follow-up.

Recipient tissue factor expression is associated with consumptive coagulopathy in pig-to-primate kidney xenotransplantation.

Consumptive coagulopathy (CC) remains a challenge in pig-to-primate organ xenotransplantation (Tx). This study investigated the role of tissue factor (TF) expression on circulating platelets and peripheral blood mononuclear cells (PBMCs). Baboons (n = 9) received a kidney graft from pigs that were either wild-type (n = 2), alpha1,3-galactosyltransferase gene-knockout (GT-KO; n = 1) or GT-KO and transgenic for the complement-regulatory protein, CD46 (GT-KO/CD46, n = 6). In the baboon where the graft developed hyperacute rejection (n = 1), the platelets and PBMCs expressed TF within 4 h of Tx. In the remaining baboons, TF was detected on platelets on post-Tx day 1. Subsequently, platelet-leukocyte aggregation developed with formation of thrombin. In the six baboons with CC, TF was not detected on baboon PBMCs until CC was beginning to develop. Graft histopathology showed fibrin deposition and platelet aggregation (n = 6), but with only minor or no features indicating a humoral immune response (n = 3), and no macrophage, B or T cell infiltration (n = 6). Activation of platelets to express TF was associated with the initiation of CC, whereas TF expression on PBMCs was concomitant with the onset of CC, often in the relative absence of features of acute humoral xenograft rejection. Prevention of recipient platelet activation may be crucial for successful pig-to-primate kidney Tx.

Investigation of lymphocyte depletion and repopulation using alemtuzumab (Campath-1H) in cynomolgus monkeys.

As the target CD52 molecule is expressed on erythrocytes of most nonhuman primate strains, using alemtuzumab in these species would cause massive hemolysis. Six cynomolgus monkeys of Indonesian origin, screened by agglutination assay for absence of CD52 on erythrocytes, were administered alemtuzumab in a cumulative dose to a maximum of 60 mg/kg. In two monkeys, mycophenolate mofetil (MMF) was added as maintenance therapy. Complete depletion of T and B lymphocytes (>99.5%) was achieved with 20 mg/kg alemtuzumab and was more profound than in monkeys treated with antithymocyte globulin (n = 5), as quantified by flow cytometry. Repopulation was suppressed by weekly injections of 10 mg/kg. Without MMF, repopulation of CD20(+)B cells and CD8(+)T cells was complete within 2 and 3 months, respectively, and repopulation of CD4(+)T cells was 67% after 1 year. MMF significantly delayed CD4(+)T-cell repopulation. Among repopulating CD4(+) and CD8(+) T cells, a phenotypic shift was observed from CD45RA(hi)CD62L(hi) naïve cells toward CD45RA(lo)CD62L(lo) effector memory cells. In lymph nodes, the depletion of naïve cells was more profound than of memory cells, which may have initiated a proliferation of memory cells. This model offers opportunities to investigate lymphocyte depletion/repopulation phenomena, as well as the efficacy of alemtuzumab in preclinical transplantation models.

Ex vivo application of carbon monoxide in UW solution prevents transplant-induced renal ischemia/reperfusion injury in pigs.

I/R injury is a major deleterious factor of successful kidney transplantation (KTx). Carbon monoxide (CO) is an endogenous gaseous regulatory molecule, and exogenously delivered CO in low concentrations provides potent cytoprotection. This study evaluated efficacies of CO exposure to excised kidney grafts to inhibit I/R injury in the pig KTx model. Porcine kidneys were stored for 48 h in control UW or UW supplemented with CO (CO-UW) and autotransplanted in a 14-day follow-up study. In the control UW group, animal survival was 80% (4/5) with peak serum creatinine levels of 12.0 +/- 5.1 mg/dL. CO-UW showed potent protection, and peak creatinine levels were reduced to 6.9 +/- 1.4 mg/dL with 100% (5/5) survival without any noticeable adverse event or abnormal COHb value. Control grafts at 14 days showed significant tubular damages, focal fibrotic changes and numerous infiltrates. The CO-UW group showed significantly less severe histopathological changes with less TGF-beta and p-Smad3 expression. Grafts in CO-UW also showed significantly lower early mRNA levels for proinflammatory cytokines and less lipid peroxidation. CO in UW provides significant protection against renal I/R injury in the porcine KTx model. Ex vivo exposure of kidney grafts to CO during cold storage may therefore be a safe strategy to reduce I/R injury.

Impact of thrombocytopenia on survival of baboons with genetically modified pig liver transplants: clinical relevance.

A lack of deceased human donor livers leads to a significant mortality in patients with acute-on-chronic or acute (fulminant) liver failure or with primary nonfunction of an allograft. Genetically engineered pigs could provide livers that might bridge the patient to allotransplantation. Orthotopic liver transplantation in baboons using livers from alpha1,3-galactosyltransferase gene-knockout (GTKO) pigs (n = 2) or from GTKO pigs transgenic for CD46 (n = 8) were carried out with a clinically acceptable immunosuppressive regimen. Six of 10 baboons survived for 4-7 days. In all cases, liver function was adequate, as evidenced by tests of detoxification, protein synthesis, complement activity and coagulation parameters. The major problem that prevented more prolonged survival beyond 7 days was a profound thrombocytopenia that developed within 1 h after reperfusion, ultimately resulting in spontaneous hemorrhage at various sites. We postulate that this is associated with the expression of tissue factor on platelets after contact with pig endothelium, resulting in platelet and platelet-peripheral blood mononuclear cell(s) aggregation and deposition of aggregates in the liver graft, though we were unable to confirm this conclusively. If this problem can be resolved, we would anticipate that a pig liver could provide a period during which a patient in liver failure could be successfully bridged to allotransplantation.

Endoscopic gastric submucosal transplantation of islets (ENDO-STI): technique and initial results in diabetic pigs.

The results of transplantation of human donor islets into the portal vein (PV) in patients with diabetes are encouraging. However, there are complications, for example, hemorrhage, thrombosis and an immediate loss of islets through the 'instant blood-mediated inflammatory reaction' (IBMIR). The gastric submucosal space (GSMS) offers potential advantages. Islets were isolated from adult pigs. Recipient pigs were made diabetic by streptozotocin. Donor islets were injected into the GSMS through a laparotomy (Group 1A, n = 4) or endoscopically (Group 1B, n = 8) or into the PV through a laparotomy (Group 2, n = 3). The pigs were followed for a maximum of 28 days. Monitoring of C-peptide in Group 1 indicated that there was minimal immediate loss of islets whereas in Group 2 there was considerable loss from IBMIR. In Group 1, there were significant reductions in mean blood glucose and mean exogenous insulin requirement between pretransplantation and 20 days posttransplantation. In Group 2, there was no significant reduction in either parameter. Insulin-positive cells were seen in the GSMS in Group 1, but not in the liver in Group 2. Endoscopic gastric submucosal transplantation of islets (ENDO-STI) offers a minimally invasive and quick approach to islet transplantation, avoids IBMIR and warrants further exploration.

Laparoscopic live donor nephrectomy: single center experience.

AIMS: The aim of this study was a retrospective assessment of the safety of laparoscopic live donor nephrectomy (LLDN) and the outcome of these renal transplantations. METHODS: From November 2001 to October 2006, we performed 30 LLDN (all left nephrectomies) after excluding any renal vascular anomalies in the donor. All laparoscopic procedures were performed by a team consisting of an expert laparoscopic surgeon and a transplant surgeon. The donor mean age was 48.9 +/- 7.6 years (range 22 to 69), 33% of the donors were men and their mean Body Mass Index was 24.7 +/- 3.8 kg/m(2). The recipients were a 32 +/- 14 years old (range 6 to 64), with 66% of them men, and their mean time on dialysis, 33 +/- 49 months (range 0 to 120). RESULTS: After a mean follow-up of 39 +/- 14 months, all donors and recipients are alive. The mean operative time was 272 +/- 41 min (range 225-360) and the mean warm ischemia time, 161 +/- 35 seconds (range 107 to 240). Surgical complications in the donors were one incisional hernia and two cases of pneumonia. The donor's mean hospital stay was 5.3 +/- 1.7 days (range 3 to 12) and their mean serum creatinine at discharge was 111 +/- 21 micromol/L. There was one surgical complication-a hematoma-among the recipients, and all transplants functioned immediately except for one case. CONCLUSIONS: LLDN was confirmed to be safe and effective, with no negative impact on transplants success. Expertise in laparoscopic surgery is needed to minimize the side effects for the transplant donor and for the recipient.

[Barrett's esophagus. Prevalence, risk of adenocarcinoma, role of endoscopic surveillance]. / L'esofago di Barret. Prevalenza, rischio di adenocarcinoma, ruolo dei programmi di sorveglianza endoscopica.

The presence of gastric metaplasia in the distal esophagus is better known as Barrett's Esophagus (BE). It is an acquired condition caused by gastro-esophageal reflux disease and is associated with a high risk of adenocarcinoma development in the distal esophagus and cardia. The definition of BE has changed over the years as only the specialized metaplasia, with the characteristic "goblet cells", has been shown to carry a risk of cancer development. BE is currently defined as the presence of intestinal metaplasia in the distal esophagus. The prevalence of intestinal metaplasia of the distal esophagus in patients undergoing endoscopy with multiple biopsies for dyspeptic symptoms, varies from 9-21% at the level of the cardia and from 1.2-8% at 3 cm above the esophago-gastric junction, with a decreasing caudo-cranial frequency. Among the BE population (intestinal metaplasia 3 or more cm long) there is a prevalence of male sex and white race, with an average age between the 5(th) and 7(th) decade. The risk of BE mucosa advancing to esophageal adenocarcinoma is not well established: incidence rates from 1/52 years-patient to 1/441 years-patient and a calculated risk from 30 to 125 times higher than in the normal population were reported. These discrepancies are probably related to: 1) temporal differences of the studies, 2) retrospective versus prospective type of the studies, 3) length of follow-up, 4) number of individuals surveilled, 5) regional variations. A literature analysis confirmed that the differences are mostly related to the number of patients studied (the larger the population the lower the incidence), are generally inversely proportional to the follow-up length (the shorter the follow-up the higher the incidence) and depend on the type of the studies (the incidence is higher in the retrospective studies than in the prospective one's). Surveillance program: esophageal adenocarcinoma is a lethal tumor with a 20% 5-year survival rate. The guidelines of The American College of Gastroenterology advice a two-year surveillance rate for BE patients without dysplasia. The difficulty with BE surveillance programs-- even if worthwhile on a single patient basis-- is that they are very expensive and at the present none of the endoscopic surveillance prospective studies has shown a positive impact in the survival rate. From our knowledge it doesn't seem wise to abandon a precautionary surveillance strategy, but further studies are needed to better understand the risk population: at the moment our advice is to monitor male patients in good general conditions with a BE segment longer than 3 cm.