First case report of multivisceral transplant from a deceased cardiac death donor.

The current shortage of pediatric multivisceral donors accounts for the long time and mortality on the waiting list of pediatric patients. The use of donors after cardiac death, especially after the outbreak of normothermic regional perfusion, has increased in recent years for all solid organs except the intestine, mainly because of its higher susceptibility to ischemia-reperfusion injury. We present the first literature case of multivisceral donors after cardiac death transplantation in a 13-month-old recipient from a 2.5-month-old donor. Once exitus was certified, an extracorporeal membrane oxygenation circuit was established, cannulating the aorta and infrarenal vena cava, while the supra-aortic branches were clamped. The abdominal organs completely recovered from ischemia through normothermic regional perfusion (extracorporeal membrane oxygenation initially and beating heart later). After perfusion with the preservation solution, the multivisceral graft was uneventfully implanted. Two months later, the patient was discharged without any complications. This case demonstrates the possibility of reducing the time spent on the waiting list for these patients.

Native Spleen Preservation During Visceral Transplantation Inhibits Graft-Versus-Host-Disease Development: Clinical and Experimental Study.

OBJECTIVE: We aimed to assess whether native spleen preservation during visceral transplantation (VT) affects graft-versus-host-disease (GVHD) incidence. SUMMARY BACKGROUND DATA: GVHD is one of the most severe and frequently lethal hematological complications after VT procedures. Because there is no specific treatment for GVHD, it is imperative to develop a strategy to reduce donor lymphocyte engraftment and proliferation. METHODS: Our study included both clinical and experimental data. A total of 108 patients were divided into 3 groups: a native spleen preservation group, a native spleen removal with no donor spleen group, and a donor spleen included (allogeneic spleen) group. We also used an allogeneic VT rat model, in which recipients were divided into 2 groups: a native spleen preservation (+SP) group and a native spleen removal (-S) group. Skin rash appearance, histopathological changes, chimerism, and spleen effects on circulating allogeneic T-cells were assessed. RESULTS: The patients with native spleen preservation showed a lower rate of GVHD ( P <.001) and better survival ( P <.05) than those in the other groups. Skin and histological signs of GVHD were lower in the rats in the +SP group ( P <.05). The donor T-cell frequency in the bloodstream and skin was also significantly reduced when the native spleen was preserved ( P <.01 and P <.0001, respectively). CONCLUSIONS: The clinical and experimental data indicate that recipient spleen preservation protects against GVHD after VT, and donor cell clearance from the bloodstream by spleen macrophages could be the underlying mechanism. Therefore, spleen preservation should be considered in VT procedures, whenever possible.

First multivisceral transplantation in Mitchell-Riley/Martinez-Frias syndrome.

BACKGROUND: MRS/MFS is a rare multisystem disorder with a poor prognosis. The high mortality rate of this syndrome is related to the severity of the associated gastrointestinal, pancreatic, and hepatobiliary conditions, as most of them are not amenable to conventional medical and surgical treatments. METHODS: We report the case of a Romani girl with all the key clinical features of MRS/MFS, and a review of cases reported in the literature. Our patient is a newborn from consanguineous parents who presented duodenal atresia, hypoplastic pancreas, gallbladder agenesis, and neonatal diabetes. Given the clinical suspicion of MRS/MFS, a genetic analysis was performed which revealed the presence of a homozygous variant in the RFX6 gene. During the course of the disease, the patient presented intractable secretory diarrhea and severe intestinal failure. RESULTS: At 2 years of age, she underwent MVT of the stomach, duodenum, small intestine, colon, liver, and pancreas. There were no surgical complications. Histologic evaluation of the small bowel showed extensive patches of gastric heterotopia. After more than 10 years of follow-up, she had presented with normal gastrointestinal, hepatic, and pancreatic function. She has one of the longest survival periods in the literature. CONCLUSIONS: Our experience suggests that multivisceral transplantation may be a promising option in select cases of MRS/MFS.

Graft infusion of adipose-derived mesenchymal stromal cells to prevent rejection in experimental intestinal transplantation: A feasibility study.

BACKGROUND: Mesenchymal stromal cells (MSC) have been proposed as a promising complement to standard immunosuppression in solid organ transplantation because of their immunomodulatory properties. The present work addresses the role of adipose-derived MSC (Ad-MSC) in an experimental model of acute rejection in small bowel transplantation (SBT). MATERIAL/METHODS: Heterotopic allogeneic SBT was performed. A single dose of 1.5x106 Ad-MSC was intra-arterially delivered just before graft reperfusion. Animals were divided into CONTROL (CTRL), CONTROL+Ad-MSC (CTRL_MSC), tacrolimus (TAC), and TAC+Ad-MSC (TAC_MSC) groups. Each Ad-MSC groups was subdivided in autologous and allogeneic third-party groups. RESULTS: Rejection rate and severity were similar in MSC-treated and untreated animals. CTRL_MSC animals showed a decrease in macrophages, T-cell (CD4, CD8, and Foxp3 subsets) and B-cell counts in the graft compared with CTRL, this decrease was attenuated in TAC_MSC animals. Pro- and anti-inflammatory cytokines and some chemokines and growth factors increased in CTRL_MSC animals, especially in the allogeneic group, whereas milder changes were seen in the TAC groups. CONCLUSION: Ad-MSC did not prevent rejection when administered just before reperfusion. However, they showed immunomodulatory effects that could be relevant for a longer-term outcome. Interference between tacrolimus and the MSC effects should be addressed in further studies.

Delayed introduction of sirolimus in paediatric intestinal transplant recipients: indications and long-term benefits.

To review our experience using sirolimus in a single centre paediatric intestinal transplantation cohort. Intestinal transplant patients with more than 3 months follow-up were divided into two groups according to their immunosuppression regimen: tacrolimus, (TAC group, n = 45 grafts) or sirolimus (SRL group, n = 38 grafts), which included those partially or completely converted from tacrolimus to sirolimus. The indications to switch were tacrolimus side effects and immunological complications. Survival and complications were retrospectively analysed comparing both groups. SRL was introduced 9 months (0 months-16.9 years) after transplant. The main cause for conversion was worsening renal function (45%), followed by haemolytic anaemia (21%) and graft-versus-host-disease (16%). Both groups showed a similar overall patient/graft survival (P = 0.76/0.08) and occurrence of rejection (24%/17%, P = 0.36). Immunological complications did not recur after conversion. Renal function significantly improved in most SRL patients. After a median follow-up of 65.17 months, 28/46 survivors were on SRL, 26 with monotherapy, with good graft function. Over one-third of our patients eventually required SRL conversion that allowed to improve their kidney function and immunological events, without entailing additional complications or survival impairment. Further trials are warranted to clarify the potential improvement of the standard tacrolimus maintenance by sirolimus conversion or addition.

Donor's graft ex vivo T-cell depletion with fludarabine reduces graft-versus-host disease signs and improves survival after intestinal transplantation - an experimental study.

Intestinal passenger T leukocytes are responsible for graft-versus-host disease (GvHD) in intestinal transplantation (ITx). We hypothesized that ex vivo fludarabine treatment of the bowel graft would diminish the risk of GvHD and improve overall survival post-transplant. We performed isolated heterotopic small bowel transplantations from Lewis (LEW) to Brown Norway (BN) rat strains, which generated GvHD signs from the fourth day post-transplant. These symptoms included rash, weight loss, piloerection, and diarrhea. The grafts of one of the experimental groups were immersed and sealed in cold Celsior preservation solution with 1000 µm fludarabine for 1 h, prior to its implantation into recipient animals. No histological signs of intestinal tissue alterations were observed after fludarabine treatment. Fludarabine-treated bowel recipients showed significantly later and milder clinical signs of GvHD and reduced total donor cell chimerism, as determined by flow cytometry using strain-specific anti-HLA antibodies. Additionally, fludarabine treatment prolonged recipients' overall survival (13.5 days ± 0.3 days vs. 9.2 days ± 0.5). We conclude that active modification of the intestinal leukocyte composition is advantageous in our ITx animal model. Immunosuppression with fludarabine during the surgical procedure, which could be translated directly to the clinic, protects bowel recipients from GvHD and improves overall post-transplant survival.

Current status of pediatric intestinal transplant in Europe.

PURPOSE OF REVIEW: This review features articles published during 2018 and 2019 regarding pediatric visceral transplantation in Europe. In this biannual review, the authors identify and summarize key articles pertinent to clinical and research areas. RECENT FINDINGS: There is a trend to a lower use of intestinal transplantation in pediatric population in Europe. Most articles were focused in long-term follow-up. The burden of the disease 10 years after intestinal transplantation is still significant, including the need of several medications, readmissions, and the need of specific follow-up, mostly because of psychiatric problems. Regarding eating behaviors, promoting eating pretransplant may be protective and there may be eating difficulty predictors that could be used to facilitate targeted interventions. Two different articles were consistent in the identification of C1q-fixing DSA as a marker of poor outcome, and capillaritis was identified as a predictor of C4d positivity in intestinal graft biopsies. The inclusion of the liver emerged as the main protective factor against dnDSA development. The incidence of PTLD (specially the monomorphic type) was significantly higher following ITx than after LTx (14.9 vs. 2.8%). The European societies and the EU have made an effort to promote networking, collaborative registries, and sharing of knowledge in pediatric transplantation. SUMMARY: Recent articles focused mostly on long-term follow-up issues, although translational research has also been sustained by some groups.

Long-term results of surgery for bowel lengthening: how many transplants are avoided, for which patients?

PURPOSE OF REVIEW: One of the biggest successes of intestinal rehabilitation programs is that more patients achieve enteral autonomy without transplantation. Many factors are responsible of this accomplishment including new parenteral formulas, better catheter management, surgical management, and the experience of the teams. The purpose of this review is to analyze recent published papers regarding intestinal lengthening procedures trying to find out how many transplantations are avoided and for which patients. RECENT FINDINGS: A trend towards performing less intestinal transplants has been identified in the last years. The general improvement of intestinal rehabilitation accounts for this step forward. However, the role of intestinal lengthening has not been clarified. SUMMARY: Surgical techniques for autologous reconstructive surgery are not limited to bowel lengthening. Longitudinal intestinal lengthening and tailoring and serial transverse enteroplasty offered good results in terms of intestinal adaptation, long-term survival, and subsequent need of intestinal transplantation. In recent series, less than one quarter of patients who underwent intestinal lengthening required salvage intestinal transplantation.

Liver transplantation for classical maple syrup urine disease: long-term follow-up.

OBJECTIVES: The aim of the study was to evaluate indications, results, and clinical and neurological evolution in children who have undergone liver transplantation for classical maple syrup urine disease (MSUD). METHODS: Descriptive study of liver transplantation for MSUD between 1991 and 2012. Eight patients were transplanted. RESULTS: Indications for transplant were poor metabolic control expressed as significant psychomotor disabilities (4 had psychomotor delays, 5 had spasticity, and 5 had epilepsy) and poor quality of life (mean number of acute metabolic decompensations and mean number of total hospitalizations before transplantation 5 and 12, respectively). Four required nasogastric tube, with a maximum 4 g/day protein-restricted diet in all of them. Seven sustained significant alterations in brain magnetic resonance imaging. Mean leucine and alloisoleucine levels were 608 (standard deviation [SD] 516) and 218 µmol/L (SD 216), respectively. All of the patients received transplants with deceased-donor livers, with ages between 1.5 and 2.5 years (mean 1.78 years). Mean posttransplantation follow-up period was 12.2 years (range 5-21 years). Final patient and graft survival was 87.5% and 75%, respectively. Following transplantation, none required hospitalization in the last 3 years nor did any have new acute metabolic decompensations following a normal diet. Five followed normal schooling, 2 had motor disabilities, and 2 had convulsive crises. Brain magnetic resonance imaging was taken in 4 patients, showing neuroimage improvement in 3 of them. Mean leucine levels were <350 µmol/L from the immediate posttransplantation period (mean 225 µmol/L, SD 78), with a maximum alloisoleucine level of 20 µmol/L. CONCLUSIONS: Liver transplantation is an effective treatment for classical MSUD that arrests brain damage, although it does not reverse the process.

Type III-B CRISPR-Cas cascade of proteolytic cleavages.

The generation of cyclic oligoadenylates and subsequent allosteric activation of proteins that carry sensory domains is a distinctive feature of type III CRISPR-Cas systems. In this work, we characterize a set of associated genes of a type III-B system from Haliangium ochraceum that contains two caspase-like proteases, SAVED-CHAT and PCaspase (prokaryotic caspase), co-opted from a cyclic oligonucleotide-based antiphage signaling system (CBASS). Cyclic tri-adenosine monophosphate (AMP)-induced oligomerization of SAVED-CHAT activates proteolytic activity of the CHAT domains, which specifically cleave and activate PCaspase. Subsequently, activated PCaspase cleaves a multitude of proteins, which results in a strong interference phenotype in vivo in Escherichia coli. Taken together, our findings reveal how a CRISPR-Cas-based detection of a target RNA triggers a cascade of caspase-associated proteolytic activities.

Post-transplant lymphoproliferative disorders and other malignancies after pediatric intestinal transplantation: incidence, clinical features and outcome.

PTLDs are a well-recognized and potentially fatal complication after intestinal transplantation. We analyzed the incidence, clinical features, and outcome in a 63 intestinal transplantation series performed in our unit between October 1999 and July 2011. Types of graft included ISB (n = 23), LSB (n = 20), and MV (n = 20). Patients were categorized into three groups of immunosuppression: I (n = 43) received basiliximab, tacrolimus, and steroids; II (n = 11) thymoglobulin and tacrolimus, and III (n = 9) alemtuzumab and tacrolimus. EBV status was serially assessed. All PTLD cases were biopsied to establish histopathological diagnosis. The incidence of PTLD was 14.2% (9/63). Median onset of PTLD after transplant was four months (range: 0.5-28), within first postoperative year in 6 (66.6%) patients. Fever was the most common symptom. Graft removal was needed in four patients (44%). The patient survival rate was 66.6% (6/9). We have not found any association between PTLD and immunosuppression regimen or transplant type. However, there was a statistical association with EBV active infection.

Ischemic preconditioning of the graft for intestinal transplantation in rats.

To test the hypothesis that two modalities of IPC should decrease acute rejection and BT after SBTx in rats. Orthotopic allogenic SBTx was performed from Wistar to BN. IPC was performed by 2 ' and 5 ' superior mesenteric artery clamping, following 2-min and 5-min reperfusion before graft cooling and retrieving. Donor-recipient sets were randomly allocated to five groups: IPC2m4d, IPC2m7d, IPC5min7d, and the control groups for the two end points; ctrl4d and ctrl7d. IRI, rejection, and BT were assessed after four or seven days depending on the groups. Measured variables included: histology, leukocyte activation by tissue MPO determination, and proinflammatory cytokines (IL-b and TNF-α) to assess inflammatory response. Leukocyte activation was significantly reduced in IPC2m7d in comparison with Ctrl and IPC5min7d. Rejection tended to be lower in IPC2min7d. Cytokine levels were contradictory and not consistent with histology. Finally, BT was less frequent in IPC2min4d group but this benefit was missed in animals with rejection (7d). Inflammatory response (MPO) was reduced and rejection tended to be lower after in IPC2m7d. Bacterial translocation was reduced in IPC2min4d but the benefit was missed at day 7.

Severe Lymphopenia as a Predictor of COVID-19 Mortality in Immunosuppressed Patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has a high mortality in certain group of patients. We analysed the impact of baseline immunosuppression in COVID-19 mortality and the role of severe lymphopenia in immunocompromised subjects. METHODS: We analysed all patients admitted with COVID-19 in a tertiary hospital in Madrid between March 1st and April 30th 2020. Epidemiological and clinical data, including severe lymphopenia (<500 lymphocytes/mm3) during admission, were analysed and compared based on their baseline immunosuppression condition. RESULTS: A total of 1594 patients with COVID-19 pneumonia were hospitalised during the study period. 166 (10.4%) were immunosuppressed. Immunocompromised patients were younger (64 vs. 67 years, p = 0.02) but presented higher rates of hypertension, diabetes, heart, neurological, lung, kidney and liver disease (p < 0.05). They showed more severe lymphopenia (53% vs 24.1%, p < 0.001), lower SapO2/FiO2 ratios (251 vs 276, p = 0.02) during admission and higher mortality rates (27.1% vs 13.5%, p < 0.001). After adjustment, immunosuppression remained as an independent factor related to mortality (Odds Ratio (OR): 2.24, p < 0.001). In the immunosuppressed group, age (OR = 1.06, p = 0.01), acute respiratory distress syndrome (ARDS) (OR = 12.27, p = 0.017) and severe lymphopenia (OR = 3.48, p = 0.04) were the factors related to high mortality rate. CONCLUSION: Immunosuppression is an independent mortality risk factor in COVID-19. Severe lymphopenia should be promptly identified in these patients.

Autoimmune cytopaenia after paediatric intestinal transplantation: a case series.

Autoimmune cytopaenia is a rare, but severe complication after solid organ transplantation. We retrospectively analysed 57 paediatric intestinal transplants performed in 49 patients between 1999 and 2009. Autoimmune cytopaenia was observed in six patients; it appeared after an average of 10 months post-transplant. Warm autoimmune haemolytic anaemia was developed in three patients, cold autoimmune haemolytic anaemia in one and two presented a mixed type. Incidence and causes for haematological cytopaenia such as the following were investigated: immunosuppression, major blood mismatch, viral infection, malignancy, passenger lymphocyte syndrome and lymphoproliferative disorders. Initial treatment included high-dose steroids, intravenous immunoglobulin, plasmapheresis and maintenance of body temperature above 37°C in those with cold autoantibodies. Inclusion of the spleen in multivisceral transplants seems to be an important risk factor. All patients, except one, relapsed after classic therapy, requiring additional treatments. Sirolimus conversion was performed in four patients. One died after infection. The immunosuppressive therapies associated with other concomitant factors, such as viral infections, lymphoproliferative disorders, graft-versus-host disease, passenger lymphocyte syndrome and the inclusion of the spleen as part of multivisceral graft seem to play an important part in the development of autoimmune processes after intestinal transplantation. Therapy is not well established, especially in those resistant to first-line treatment.

The use of sirolimus as a rescue therapy in pediatric intestinal transplant recipients.

To review our experience with SRL as a second-line therapy in our series of 45 SBTx recipients (1997-2009). Retrospective review of five children converted to SRL: 3 M/2 F; median of three yr old (range 20 months-18 yr); rescue indications, adverse events with SRL, resolution of tacrolimus-related side effects, incidence of rejection, PTLD, or GVHD were summarized. Tacrolimus was discontinued (average 13 months after transplant) because of refractory hemolytic anemia in four patients with decreased renal function and because of advanced renal failure and unclear neutropenia in one. PTLD and GVHD had been previously diagnosed in two. Tacrolimus-related side effects disappeared in all five although other immunosuppressants and splenectomy were used simultaneously or later in most of them. Adverse events reported after the conversion were infections (tuberculosis and Pneumocystis carinii in two) and mild hypertriglyceridemia. No rejection, GVHD, or PTLD episode was observed. Four patients are alive with excellent quality of life (median follow-up 18 months). Sirolimus is a safe rescue therapy in SBTx children when tacrolimus is not well tolerated. Renal function and hematologic disorders seem to improve, although other simultaneous strategies could be also involved. Further studies could demonstrate its efficacy as a first-line treatment.

New mutations associated with Hirschsprung disease.

INTRODUCTION: Hirschsprung Disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications. MATERIAL AND METHODS: Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013. RESULTS: We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene: Two of the mutations are novel and they have not been reported in the medical literature. CONCLUSIONS: The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

[New mutations associated with Hirschsprung disease]. / Nuevas mutaciones asociadas a la enfermedad de Hirschsprung.

INTRODUCTION: Hirschsprung disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications. MATERIAL AND METHODS: Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013. RESULTS: We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene. Two of the mutations are novel and they have not been reported in the medical literature. CONCLUSIONS: The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

Long-Term Results after Diversion Surgery in Extrahepatic Portal Vein Obstruction.

AIM: Extrahepatic portal vein obstruction (EHPVO) is a frequent cause of noncirrhotic portal hypertension in children. The aim of this study is to analyze long-term results after diversion surgery. PATIENTS AND METHODS: Retrospective review of EHPVO patients who underwent diversion surgery analyzing number of platelets, leukocytes, prothrombin activity, splenomegaly, and gastrointestinal bleeding 10 years after surgery. RESULTS: Thirty-three patients were evaluated, mostly males (64%) and presenting with gastrointestinal bleeding (46%). Mesoportal shunt (Rex) was performed in 19 patients, mesocaval in 7, distal splenorenal in 7, and proximal splenorenal in 3. While comparing mesoportal shunt to the other portosystemic shunts, an increase in platelets was found with every technique, but it was clearly higher in mesoportal shunt. The highest increase was 6 months after surgery (p = 0.0015) as well as prothrombin activity (p = 0.0003). Leukocytes level also increased without statistical significance. Spleen size (cm) and spleen size Z score (SSAZ) decreased significantly 6 months after mesoportal shunt (p = 0.0168). Before surgery, over 94% patients suffered gastrointestinal bleeding, which reduced significantly afterward with bleeding episodes in only four (12%) of them. CONCLUSION: Diversion surgery in EHPVO, especially mesoportal shunt of Rex, improves hepatic function (prothrombin activity), reduces hypersplenism (platelets, leukocytes, and spleen size), and decreases gastrointestinal bleeding episodes.

Prognostic Factors for Liver Transplantation in Unresectable Hepatoblastoma.

AIM: Hepatoblastoma is the most frequent hepatic tumor in children, and its initial presentation will affect treatment and prognosis. The aim of this study is to evaluate long-term results of liver transplantation in children with unresectable hepatoblastoma. PATIENTS AND METHODS: This is a retrospective review of patients with hepatoblastoma who underwent liver transplantation, analyzing risk factors, tumor presentation, treatment, and long-term survival to identify prognostic factors. RESULTS: Thirty-one patients underwent liver transplantation in the context of unresectable hepatoblastoma, mainly males (67%) and with risk factors such as prematurity (12.9%), maternal smoking (6.5%), and familial adenomatous polyposis (3.2%). Most frequent presentation was multifocal PRETEXT III (51.6%) and PRETEXT IV (45.2%), with metastasis at diagnosis in 12.9% and vascular involvement in 54.8%.Twenty-one patients received a living-donor (67.7%) and 10 a cadaveric graft (32.2%), at 31.7 months of age (5-125). Most transplants were primary, and only two were performed as rescue therapy after an attempt of surgical resection of the tumor.Overall survival 1 and 5 years after transplantation were 93.3% ± 4.6% and 86.4% ± 6.3%, respectively. We could not find any statistically significant differences between risk factors, tumor presentation, type of graft, or type of transplant. CONCLUSION: Liver transplantation has increased hepatoblastoma survival in unresectable tumors. Probably due to these good results, we have not been able to find significant prognostic factors in this cohort.