Gabriel J. Echeverri

Hepatic Function After Genetically Engineered Pig Liver Transplantation in Baboons

Background. If “bridging” to allo-transplantation (Tx) is to be achieved by a pig liver xenograft, adequate hepatic function needs to be assured. Methods. We have studied hepatic function in baboons after Tx of livers from &agr;1,3-galactosyltransferase gene-knockout (GTKO, n=1) or GTKO pigs transgenic for CD46 (GTKO/CD46, n=5). Monitoring was by liver function tests and coagulation parameters. Pig-specific proteins in the baboon serum/plasma were identified by Western blot. In four baboons, coagulation factors were measured. The results were compared with values from healthy humans, baboons, and pigs. Results. Recipient baboons died or were euthanized after 4 to 7 days after internal bleeding associated with profound thrombocytopenia. However, parameters of liver function, including coagulation, remained in the near-normal range, except for some cholestasis. Western blot demonstrated that pig proteins (albumin, fibrinogen, haptoglobin, and plasminogen) were produced by the liver from day 1. Production of several pig coagulation factors was confirmed. Conclusions. After the Tx of genetically engineered pig livers into baboons (1) many parameters of hepatic function, including coagulation, were normal or near normal; (2) there was evidence for production of pig proteins, including coagulation factors; and (3) these appeared to function adequately in baboons although interspecies compatibility of such proteins remains to be confirmed.

Systemic inflammation in xenograft recipients precedes activation of coagulation

Dysregulation of coagulation is considered a major barrier against successful pig organ xenotransplantation in non‐human primates. Inflammation is known to promote activation of coagulation. The role of pro‐inflammatory factors as well as the relationship between inflammation and activation of coagulation in xenograft recipients is poorly understood.

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‐β 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.

T-cell-based immunosuppressive therapy inhibits the development of natural antibodies in infant baboons

Background. We set out to determine whether B-cell tolerance to A/B-incompatible alloantigens and pig xenoantigens could be achieved in infant baboons. Methods. Artery patch grafts were implanted in the abdominal aorta in 3-month-old baboons using A/B-incompatible (AB-I) allografts or wild-type pig xenografts (pig). Group 1 (Gp1) (controls, n=6) received no immunosuppressive therapy (IS) and no graft. Gp2 (n=2) received an AB-I or pig graft but no IS. Gp3 received AB-I grafts+IS (Gp3A: n=2) or pig grafts+IS (Gp3B: n=2). IS consisted of ATG, anti-CD154mAb, and mycophenolate mofetil until age 8 to 12 months. Gp4 (n=2) received IS only but no graft. Results. In Gp1, anti-A/B and cytotoxic anti-pig immunoglobulin-M increased steadily during the first year. Gp2 became sensitized to donor-specific AB-I or pig antigens within 2 weeks. Gp3 and Gp4 infants that received anti-CD154mAb made no or minimal anti-A/B and anti-pig antibodies while receiving IS. Discussion. The production of natural anti-A/B and anti-pig antibodies was inhibited by IS with anti-CD154mAb, even in the absence of an allograft or xenograft, suggesting that natural antibodies may not be entirely T-cell independent. These data are in contrast to clinical experience with AB-I allotransplantation in infants, who cease producing only donor-specific antibodies.

Technique of endoscopic biopsy of islet allografts transplanted into the gastric submucosal space in pigs.

Currently, islet cells are transplanted into the liver via portal vein infusion. One disadvantage of this approach is that it is not possible to adequately biopsy the islets in the liver to assess for rejection. Islet transplantation (Tx) into the gastric submucosal space (GSMS) can be performed endoscopically and has the potential advantage of histological evaluation by endoscopic biopsy. The aim of this study was to determine whether a representative allograft sample could be obtained endoscopically. We performed islet Tx into the GSMS in nonimmunosup-pressed pigs using simple endoscopic submucosal injection. Islets were transplanted at four sites. Endoscopic ultrasonography and biopsy of the transplanted islets at two sites by modified endoscopic submucosal dissection were carried out successfully in all pigs 5 days after islet Tx. Tissue obtained at both biopsy and necropsy (including full-thickness sections of the gastric wall around the sites of the remaining islets and biopsies) were examined by histology and immunohistochemistry to confirm the presence of the islet grafts and any features of rejection. Representative allograft sampling was successfully obtained from all biopsy sites. All biopsies included islets with insulin-positive staining. There was significant CD3+ and CD68+ cell infiltration in the islet masses obtained at biopsy and from sections taken at necropsy, with similar histopathological features. Endoscopic biopsy of islet allografts in the GSMS is feasible, provides accurate histopathological data, and would provide a significant advance if translated into clinical practice.

Kidney transplantation for end-stage renal disease in lupus nephritis, a very safe procedure: a single Latin American transplant center experience

Background Lupus nephritis (LN) is one of the most frequent complications of SLE and occurs in up to 50% of cases depending on the studied population. Of these, approximately 20% progress to end-stage renal disease (ESRD), with the treatment of choice being a kidney transplant. Objective The objective of this study was to describe the clinical outcome of patients transplanted due to LN, compared with patients transplanted for other causes, in a Latin American population from the Fundación Valle del Lili in Cali, Colombia. Methods Observational, retrospective case study with controls matched by age, sex and type of donor in a single center between 1996 and 2014. Results Sixty-five kidney transplants were performed in patients with LN and ESRD. The survival of patients with LN was 98% at 1, 10 and 15 years (p = .99). For controls by age and sex, survival was also 98% at 15 years post-transplant, and for controls by donor, the survival rate was 100% at 5 years and 98% at 15 years. Graft survival in patients with LN to 1, 5 and 15 years was 92%, 83% and 71%, respectively; for controls by age and sex, it was 90%, 84% and 64%, respectively, and for the controls by donor, it was 89%, 86% and 79%, respectively (p = .7718). There were no statistically significant differences found in the cumulative incidence of acute graft rejection in the first year, but it was found that acute rejection is a factor that relates to the loss of function of the renal graft (p = .032). Of the patients transplanted for LN, two (3.1%) experienced a recurrence of the disease. One patient died after a diagnosis of recurrence of LN due to an infection. Conclusions Kidney transplantation is a good option for patients with ESRD due to LN. In this Hispanic population, the survival of patients, graft survival, and cumulative incidence of graft rejection are not different from those of other transplanted patients. In addition, recurrence of LN was rare, showing the benefits of renal transplantation in LN patients with ESRD.

Sclerosing Encapsulated Peritonitis: A devastating and infrequent disease complicating kidney transplantation, case report and literature review

Highlights • Sclerosing encapsulating peritonitis is a rare and dangerous complication.• Kidney transplanted patients with peritoneal dyalisis history are in risk of SEP.• Adhesiolisis is the ideal surgical management for Sclerosing encapsulating peritonitis.

Liver Angiosarcoma: Rare tumour associated with a poor prognosis, literature review and case report.

Highlights • Liver Angiosarcoma is rare and aggressive tumour that requires surgical management.• Partial Hepatectomy is the ideal surgical management for Liver Angiosarcoma.• Liver transplant does not improve the survival of Liver Angiosarcoma patients.

Hepatitis A, cardiomyopathy, aplastic anemia, and acute liver failure: A devastating scenario

Hepatitis A virus (HAV) causes an acute infection and is usually asymptomatic in children. When clinical manifestations appear, these include choluria, jaundice, and abdominal pain. Although infrequent, extra‐hepatic manifestations related to HAV have been described, affecting the heart, bone marrow, blood vessels, and other tissues.A 10‐year‐old boy from a rural area presented with a 15‐day history of malaise, fever, and jaundice; laboratory examinations were compatible with HAV infection. The patient turned encephalopathic and was remitted to our center, where laboratory examinations showed a medullary aplasia and fulminant hepatitis requiring a liver transplant that was performed 72 hours after admission. At 24 hours post transplant, the patient developed a cardiomyopathy secondary to HAV, and intravenous immunoglobulin was administered. The patient is still alive and attending his medical check‐ups.Although rare, extra‐hepatic manifestations of HAV infection have been described in 14% of cases. The groups of patients affected are usually aged and present with high bilirubin levels. Acquired aplastic anemia and myocarditis caused by HAV are uncommon, and its pathophysiology has not yet been elucidated.HAV infection is usually asymptomatic in children, although extra‐hepatic manifestations can appear requiring early detection and management.

Hepatoblastoma: Transplant Versus Resection Experience in a Latin American Transplant Center

Background Hepatoblastoma is the most common primary malignant liver tumor in children and is usually diagnosed during the first 3 years of life. Overall survival has increased 50% due to chemotherapeutic schemes, expertise surgery centers, and liver transplantation. Methods A retrospective collection of data was performed from pediatric patients with diagnosis of hepatoblastoma. Variables included demographic, diagnostic tools and histological classification; chemotherapy and surgical treatment; and outcomes and patient survival. The PRETEXT classification was applied, which included the risk evaluation, and according to the medical criterion in an individualized way, underwent resection or transplant. The morbidity of patients was evaluated by the Clavien-Dindo classification. Statistical analysis was performed according to the distribution of data and the survival analysis was carried out using the Kaplan-Meier method. Results The patients (n = 16) were divided in a resection group (n = 8) and a transplant group (n = 8). The median age at the time of diagnosis was 13.5 months. The motive for the initial consultation was the discovery of a mass; all patients had high levels of &agr;-fetoprotein and an imaging study. Ten of 16 patients required chemotherapy before the surgical procedure. In the resection group, 5 of 8 patients were classified as Clavien I and 4 of 8 patients of the transplant group were classified as Clavien II. Patient survival at 30 months was 100% in the resection group and 65% in the liver transplantation group. Conclusions To our knowledge, this is the first case report of pediatric patients with hepatoblastoma and liver resection or transplant in Colombia and Latin America. Our results are comparable with the series worldwide, showing that resection and transplant increase the survival of the pediatric patients with hepatoblastoma. It is important to advocate for an increase of reporting in the scientific literature in Latin America.