Native Spleen Research Articles

Case Report: Challenging diagnostic of an accessory spleen mimicking a retroperitoneal tumor: A case report and review of the literature

Background: The accessory spleen is a congenital defect with an additional splenic tissue to the native spleen due to an incomplete fusion of splenic masses during the embryologic period. The preoperative diagnosis is usually mistaken for a retroperitoneal neoplasm. The aim of the present manuscript is to highlight the diagnostic difficulties of a retroperitoneal spleen. Case presentation: A 41-year-old woman was admitted to the surgical department of Habib Thameur Hospital, Tunis, for an abdominal mass discovered by auto palpation associated with a left lower quadrant pain. The computed tomographic scan showed a heterogeneous and partially necrotic retroperitoneal mass located along the left primitive iliac vessels. Arterial supply to the mass arose from the aorta and the left iliac vessel. The spleen was normal. MRI examination showed a left retroperitoneal heterogeneous and necrotic mass, surrounding the iliac vessels extended from the aortic to the left iliac bifurcation, hyper vascularized at the arterial time with a peripheral capsule intensely enhanced, and there were two other lateroaortic vascularized masses. The patient had a laparotomy resection of the retroperitoneal mass. The result of the specimen examination was an accessory spleen. The postoperative outcome was uneventful. Conclusion: An accessory spleen on the retroperitoneal position is extremely uncommon. Preoperative diagnosis is still challenging. The main misdiagnosis was neoplastic disease.

Abdominal and pelvic splenosis: atypical findings, pitfalls, and mimics

Splenosis is an acquired form of ectopic splenic tissue that typically arises after trauma or splenectomy. It is often an incidental image finding in an otherwise asymptomatic patient, but the spectrum of symptoms varies based on the site of implantation. Radiologists should be familiar with the imaging features of splenosis to avoid mistaking it for malignancy. Splenosis has identical imaging features to that of the native spleen on US, CT, MRI, and nuclear medicine examinations. Therefore, when the radiologic findings support the diagnosis of splenosis, the patient can be spared invasive procedures for tissue sampling.

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

We aimed to assess whether native spleen preservation during visceral transplantation (VT) affects graft-versus-host-disease (GVHD) incidence. 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. 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. 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). 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.

EXPERIMENTAL EVIDENCE ON THE ROLE OF THE SPLEEN IN GRAFT VERSUS HOST DISEASE AFTER VISCERAL TRANSPLANTATION

Introduction: Graft versus host disease (GVHD) is one of the most severe complications after visceral transplantation (VT); its incidence in various series ranges from 5% to 20%, and mortality is disappointingly high, ranging from 40% to 70%. Native spleen removal has been common practice in patients undergoing MVTx. For some years, the donor spleen was included in the graft, in an attempt to compensate for the resulting asplenic state. Nowadays, different criteria are used in surgical practice regarding recipient splenectomy during visceral transplantation. We aimed to assess native spleen preservation role in an experimental model of graft-versus-host-disease (GVHD) after allogeneic modified multivisceral transplantation (MMVTx). Material and Methods: Allogeneic Heterotopic MMVTx (Lew to BN) that reproduces GVHD signs was performed. Rats recipients were divided in two groups, native spleen preservation (+SP) and native spleen removal (-S). GVHD clinical and histopathological incidence was evaluated. Also, in order to determine the effect of native spleen preservation, CellTrace Violet-stained LEW PBMCs were injected in a non-transplanted BN rat and performed a partial splenectomy and then a full splenectomy (24 and 48 h post-cell injection, respectively). Results: Incidence of clinical and histological signs of GVHD after experimental MMVTx is reduced by recipient spleen preservation. Macroscopic skin GVHD manifestations were significantly more frequent in the MMVTx-S recipients compared with the MMVTx+SP group (p<.05). The histological analysis showed significant differences in the GVHD skin scale used between the MMVTx-S and MMVTx+SP groups. As shown in Figure A and B, LEW CellTrace Violet-stained CD3+cells were detected in the bloodstream 2 h after PBMC injection, with a clear decrease in their frequency 48 h later. In a consistent manner, the percentage of CellTrace Violet+ BN MHC I- T-cells in the spleen was significantly lower 48 h after PBMC injection compared with 24 h (Fig. C and D, p<.05), indicating clearance of LEW cells from both blood and spleen. However, as depicted in Figures E and F, no differences in the percentage of CD3+Annexin+ cells between LEW and BN lymphocytes were observed at 24 h (Lewis: 3.7% ± 0.3% and BN: 4% ± 0.4%) or 48 h (LEW: 3.2% ± 0.5% and BN: 4.1% ± 0.7%). Considering that LEW PBMCs had absorbed CellTrace Violet dye, we hypothesized that macrophages would become positive for this fluorochrome if they engulfed them. As shown in Figures G and4H, 12.5% ± 1.9% of BN macrophages become CellTrace Violet-positive 24 h after PBMC injection and 23.5% ± 2.1% after 48 h.Conclusion: Spleen preservation attenuates clinical signs of GVHD after MMVTx. Spleen marophages ability to internalize allogenic cells could explain the lower frequency of donor T-cells in the spleen preservation group versus the splenectomized animals. All these data suggest a possible mechanism that links spleen preservation during VT and lower GVHD incidence.

The Role of Visceral Transplantation for Neoplastic Disease

AbstractVisceral transplantation has been utilized as the most radical surgical treatment for neoplasms not amenable to conventional resection. The main indications for this procedure include mesenteric desmoid tumors threatening the root of mesentery and metastatic neuroendocrine neoplasms. Published case-series of visceral transplantation for such indications are reviewed in this article. Patients with desmoid tumors associated with familial adenomatous polyposis are transplanted with intestinal or multivisceral allografts. With surgical modification of technique, the native spleen is preserved while duodenopancreatic complex is removed to obviate the risk of malignant transformation of duodenal polyposis after transplantation. Preservation of spleen decreased incidence of post-transplant lymphoproliferative disorder, conferring therapeutic advantage. Patient survival is comparable to that of other indications, and desmoid tumor recurrence has been observed in the recipient tissue but not in the donor allograft. For visceral transplantation of metastatic neuroendocrine neoplasms, the majority of these patients have diffuse liver involvement, thus requiring full multivisceral transplantation. Post-transplant patient survival is acceptable with limited data available on recurrence. Autotransplantation following ex vivo tumor resection using visceral allografts has been also performed in a limited, select cohort of patients with various pathologies. Adenocarcinomas are associated with a prohibitive recurrence rate following the procedure, and its use for this indication is therefore not recommended. A national database of visceral transplantation undertaken for neoplastic disease should be developed to better understand predictors of outcomes and to help produce and standardize selection criteria.

Autologous Splenocyte Reinfusion Improves Antibody-Mediated Immune Response to the 23-Valent Pneumococcal Polysaccharide-Based Vaccine in Splenectomized Mice.

Common clinical options, currently, for necessary splenectomy are vaccinations and antibiotic prophylaxis. However, despite these two adjuncts, there still occur numerous cases of overwhelming post-splenectomy infection. To examine whether reperfusion of critical splenic lymphocytes could boost immune response, we harvested splenic lymphocytes, reperfused the autologous lymphocytes, and then administered a pneumococcal vaccine (PNEUMOVAX®23, i.e., PPSV23) in splenectomized mice. We found that splenectomy impaired the immune response in the splenectomized group compared to the non-splenectomized group; the splenectomized group with lymphocyte reinfusion had a higher response to polysaccharide vaccination based on antibody titer than the splenectomized group without lymphocyte reinfusion. The sham group with the native spleen had the most elevated antibody titer against the PPSV23 polysaccharide antigen. This may be additive, resulting from contributions of the splenic structure, along with the phagocytic function of the spleen and its constituent cells affecting the antibody response. Reinfusion of splenic lymphocytes may enhance immunity without the complications associated with splenic fragment autotransplantation, which never gained acceptance. This technique is safe and simple since the splenic lymphocytes are autologous and, therefore, not self-reactive, and very similar to autologous blood transfusion. This concept may be beneficial in cases of unavoidable splenectomy, especially in pediatric cases.

Spleen Organoid Units Generate Functional Human and Mouse Tissue-Engineered Spleen in a Murine Model

Introduction: Splenectomy is common after trauma or hematologic disease, and alters immune protection against pathogens, which may lead to fulminant infection with high mortality. Yet the spleen has demonstrable regenerative capacity and cells might be recovered and reimplanted at the time of injury or excision to avoid these risks. Methods: Tissue-engineered spleen (TESp) was generated from ActinGFP mice (mTESp) or human donor spleen (hTESp) through implantation of spleen organoid units (spleen OU), in NOD/SCID mice with concurrent splenectomy, on a biodegradable scaffold. Explants were evaluated and blood smears were obtained to investigate the presence of target cells or Howell-Jolly bodies, which are erythrocyte sequelae of asplenia. Results: TESp was generated from mouse (mTESp) and human (hTESp) donor cells with essential splenic components: red and white pulp with trabeculae. mTESp and hTESp demonstrated green fluorescent protein- or lamin-positive costaining with proliferating cell nuclear antigen, CD4, and CD11c, identifying proliferative donor cells and key immune components of the spleen of donor origin. Animals with hTESp and mTESP combined with splenectomy had significantly fewer Howell-Jolly bodies on blood smears than controls. Conclusion: TESp from mouse and human donor cells can be generated by 4 weeks and contains donor immune cells identified by CD4 and CD11c. TESp reduces postsplenectomy erythrocyte inclusions, indicating possible function. Impact Statement Overwhelming postsplenectomy infection is rare but highly mortal. Tissue-engineered spleen (TESp) was generated from murine (mTESp) and human (hTESp) donors and appeared histologically similar to native spleen. Both mTESp and hTESp demonstrated proliferative cells of donor spleen origin. Importantly, functional cells were demonstrated on imaging with a corresponding reduction in the number of erythrocyte inclusions in blood smears that are typically identified in patients with asplenia and indicate a lack of clearance by functional spleen tissue. Taken together, these findings indicate that this approach might be clinically relevant as a future human therapy.

Twenty Years of Gut Transplantation for Chronic Intestinal Pseudo-obstruction: Technical Innovation, Long-term Outcome, Quality of Life, and Disease Recurrence.

To define long-term outcome, predictors of survival, and risk of disease recurrence after gut transplantation (GT) in patients with chronic intestinal pseudo-obstruction (CIPO). GT has been increasingly used to rescue patients with CIPO with end-stage disease and home parenteral nutrition (HPN)-associated complications. However, long-term outcome including quality of life and risk of disease recurrence has yet to be fully defined. Fifty-five patients with CIPO, 23 (42%) children and 32 (58%) adults, underwent GT and were prospectively studied. All patients suffered gut failure, received HPN, and experienced life-threatening complications. The 55 patients received 62 allografts; 43 (67%) liver-free and 19 (33%) liver-contained with 7 (13%) retransplants. Hindgut reconstruction was adopted in 1993 and preservation of native spleen was introduced in 1999. Immunosuppression was tacrolimus-based with antilymphocyte recipient pretreatment in 41 (75%). Patient survival was 89% at 1 year and 69% at 5 years with respective graft survival of 87% and 56%. Retransplantation was successful in 86%. Adults experienced better patient (P = 0.23) and graft (P = 0.08) survival with lower incidence of post-transplant lymphoproliferative disorder (P = 0.09) and graft versus host disease (P = 0.002). Antilymphocyte pretreatment improved overall patient (P = 0.005) and graft (P = 0.069) survival. The initially restored nutritional autonomy was sustainable in 23 (70%) of 33 long-term survivors with improved quality of life. The remaining 10 recipients required reinstitution of HPN due to allograft enterectomy (n = 3) or gut dysfunction (n = 7). Disease recurrence was highly suspected in 4 (7%) recipients. GT is life-saving for patients with end-stage CIPO and HPN-associated complications. Long-term survival is achievable with better quality of life and low risk of disease recurrence.

P3.60: Native spleen preservation attenuate graft versus host disease in an experimental model of modified multivisceral transplantation.

Introduction: Native spleen used to be removed in patients undergoing modified multivisceral transplantation (MMVT) increasing the risk of sepsis and graft-versus-host disease (GVHD). The mechanistic basis of these effects including mixed chimerism level is poorly understood. Based on a novel experimental procedure of MMVT that triggers GVHD, we aimed to evaluate the effects of native spleen preservation in this model in order to gain insight into the mechanisms that may mediate this phenomenon. Material and Methods: Heterotopic MMVT from Lewis to Brown Norway rats was performed. MMVT graft consisted of stomach, duodenum, pancreas, spleen and the small bowel of the donor. The native spleen was removed (MMVT-S) in half of the MMVT recipients (N=5), while the remaining preserved their own spleen (MMVT+NSP) (N=5). After MMVT mixed hematopoietic chimerism was determined in native spleen and peripheral blood samples by flow cytometry using strain-specific HLA antibodies. Also, histopathological (using Pintar score) and clinical signs of GVHD such as skin rash were evaluated. Results: all animals in the group MMVT-S presented clinical signs of GVHD such as skin rash, weight loss, and diarrhea, among others, between 7–10 days after transplantation. Skin rash was particularly remarkable in the ears and periocular area. Clinical signs of GVHD were less frequent in MMVT+NSP recipients (40%; p<0.05). Also, significant differences between groups were observed in the histopathological study and mixed chimerism in peripheral blood 3 days after MMVT (36.6 and 23.62 % in MMVT-S and MMVT+NSP respectively) (Figure 1). Also, native spleen showed an 18±5 % of chimerism (CD3+ donor cells) 1 week after transplantation. After day 10 post-MMVT, when the signs of transient GVHD disappeared, both groups presented graft rejection. Conclusions: Native spleen preservation in MMVT recipients attenuated the occurrence of GVHD and reduced the level of chimerism compared to recipients that underwent spleen removal during MMVT. Despite more studies are necessary, our preliminary results suggest that native spleen preservation increase the efficacy in removal of anti-recipient reactive clones that would explain the protective effect of native spleen preservation against GVHD.

310.7: Spleen preservation attenuates GVHD in multivisceral transplant recipients.

Purpose: The immunological benefits of the spleen are well acknowledged, but splenectomy is often performed in recipients of multivisceral transplantation. Technical reason and the lack of room in the abdominal cavity are the key arguments to justify removal of the native spleen. We aimed to analyze the beneficial role of the spleen in MVTx recipients in a series of pediatric intestinal transplantation. Patients and methods: A total of 103 IT (55MV, 25SB, 22CLSB, 3MMV) were performed in 84 patients (male-60%-, mean age 5.3yrs) between 1999 and 2018. Mean time on the waiting list was 272days waiting list mortality was 25%. Main indications for the transplant on the first instance were short bowel syndrome (69%), motility disorders(12%) and epithelial diseases(9.5%). For the present study we included only pediatric (<18 years) cases that underwent multivisceral transplantation. Patients were divided patients in three groups, native spleen preservation, native spleen removal and spleen graft inclusion. We analyzed survival, GVHD, hemolytic disorders. Results: From the whole series, only 55 patients were included, all of them received a multivisceral graft. The spleen was included in the graft in 18.1% of patients, splenectomy was performed in 40%, in several of them after failed attempt of preservation; and native spleen was preserved in 41.8% Rejection in different forms was more frequent in patients who preserved the spleen, 4% presented humoral rejection, and acute cellular rejection was two times and chronic rejection four times more frequent compared with patients who underwent splenectomy. None of the patients with the spleen included in the graft presented humoral or chronic rejection, PTLD was also (1.8 times) more frequent in this group. The proportion of GVHD was significantly lower in the group of spleen preservation compared to splenectomy and graft spleen (RR 2.75, OR 3.33) (p<0.05). We also found a trend towards less hemolytic disorders in patients with spleen preservation. Conclusion: Native spleen preservation demonstrated to attenuate the occurrence and severity of GVHD in pediatric MVTx recipients. This technique should be considered in all patients, although technical difficulties, prolonged ischemia of the graft and other factors can preclude the success of the procedure.

P1.15: Paediatric domino liver transplant following multivisceral transplant (liver-inclusive) with splenic preservation – A case report

Introduction:A multivisceral transplant followed by domino implantation of the resected liver to another patient was first reported by Tzakis in 1999. Since then there has not been much development in this technique and its implications for both recipients. We present a paediatric multivisceral transplantation with native spleen preservation followed by the use of the recipient’s liver as a domino graft for another child. Patients and Methods:Multivisceral donor: 3 year old boy with hypoxic brain damage, blood group O+, weight 14kg. Multivisceral recipient: 7 year old boy, blood group A+, weight 24 kg, with severe intestinal failure (Neuropathic intestinal dysmotility). No enteral feed and 24-h PN, with persistent central line infections. Listed for multivisceral transplant seeking immunological advantage. At transplant, normal native liver (mild portal fibrosis at biopsy) preserved for domino transplant. Splenic artery and left gastric artery were preserved. Pancreas removed leaving splenic vein. Spleno-caval shunt performed preserving native spleen. Native liver perfused with UW solution and stored. Multiorgan graft implanted (liver, stomach, duodenum, pancreas, small bowel and right haemicolon). CIT: 10h. Domino liver recipient: 3 year old boy, blood group: A+, weight 12 kg, with cholestatic liver disease. Domino liver transplant (graft weight: 484 g, CIT: 10h, duct-to-duct anastomosis). Results:Multivisceral recipient had bowel obstruction (day 3 post-transplant) that required laparotomy. No acute cellular rejection and no serious infections post-operatively. Stoma reversed at 5 m. He remains on enteral feeding and PN support due to rapid bowel transit. The domino liver recipient had acute cellular rejection (day 8 post-transplant). Anastomotic biliary stricture corrected with biliary reconstruction (6 m post-transplant). Conclusion:A liver-inclusive intestinal transplant seems to give an immunological advantage to the recipient by decreasing rejection episodes but make them vulnerable to lethal infections (Wu & Cruz, 2018), which is maybe worsened by native splenectomy at transplantation. Preserving the native spleen may reduce the incidence of PTLD, GVHD and risk of infections. The above case could be a better option than a modified multivisceral transplantation and using the multivisceral recipient’s liver as a domino graft will decrease the impact on the donor pool. More cases are required to establish the advantages of these surgical techniques.

A Mouse Model of Vascularized Heterotopic Spleen Transplantation for Studying Spleen Cell Biology and Transplant Immunity.

The spleen is a unique lymphoid organ that plays a critical role in the homeostasis of the immune and hematopoietic systems. Patients that have undergone splenectomy regardless of precipitating causes are prone to develop an overwhelming post-splenectomy infection and experience increased risks of deep venous thrombosis and malignancies. Recently, epidemiological studies indicated that splenectomy might be associated with the occurrence of cardiovascular diseases, suggesting that physiological functions of the spleen have not yet been fully recognized. Here, we introduce a mouse model of vascularized heterotopic spleen transplantation, which not only can be utilized to study the function and behavioral activity of splenic immune cell subsets in different biologic processes, but also can be a powerful tool to test the therapeutic potential of spleen transplantation in certain diseases. The main surgical steps of this model include donor spleen harvest, the removal of recipient native spleen, and spleen graft revascularization. Using congenic mouse strains (e.g., mice with CD45.1/CD45.2 backgrounds), we observed that after syngeneic transplantation, both donor-derived splenic lymphocytes and myeloid cells migrated out of the graft as early as post-operative day 1, concomitant with the influx of multiple types of recipient cells, thus generating a unique chimera. Despite relatively challenging techniques, this procedure can be performed with >90% success rate. This model allows tracking the fate, longevity, and function of splenocytes during steady state and in a disease setting following a spleen transplantation, thereby offering a great opportunity to discover the distinct role for spleen-derived immune cells in different disease processes.

Effect of Native Spleen Preservation in an Experimental Model of Modified Multivisceral Transplantation

Introduction Native spleen is usually removed in patients undergoing modified multivisceral transplantation (MMVT) increasing the risk of sepsis and graft-versus-host disease (GVHD). On the other hand, it has been reported that spleen preservation also increases the risk of allograft rejection. The mechanisms of theses effects including mixed chimerism level are poorly understood. Based on a novel experimental model of MMVT that triggers GVHD, we hypothesized that native spleen preservation attenuate GVHD after MMVT. Methods Isolated heterotopic intestinal transplantation (IT) or heterotopic MMVT from Lewis (LEW) to Brown Norway (BN) rats was performed. IT graft consisted in 80% of the small bowel, and MMVT graft consisted of the distal half of the stomach, duodenum, pancreas, spleen and the small bowel of the donor. The native spleen was removed (MVM-S) in half of the MMVT recipients (N=5), while the remaining preserved their own spleen (MVM+SP) (N=5). After MMVT or IT, the mixed hematopoietic chimerism was determined in peripheral blood samples by flow cytometry using strain-specific HLA antibodies and clinical signs of GVHD such as skin rash were evaluated. Results All animals in the group MVM-S presented clinical signs compatible with GVHD such as skin rash, weight loss, and diarrhea, among others, between 7 and 10 days after transplantation. Skin rash was particularly remarkable in the ears, snout and periocular area. Clinical signs of GVHD were less frequent in MVM-S and IT animals (100% vs 40% and 40%, p<0.05) Flow cytometry found that mixed chimerism was significantly higher in the MVM-S group, compared to the MVM+SP group (percentage donor’s lymphocytes in peripheral blood at 3 and 7 post-transplant days (PTD): 36,6% (30-53%) and 9,4% (3-18%) vs 23,6% (19-26%) and 20,5 (18-25,5%) respectively; p<0.05) (Figure 1). The level of chimerism gradually decreased as clinical signs of rejection appeared.Conclusion Allogeneic heterotopic MMVT in the strain combination L-BN yielded a higher rate of GVHD compared to IT. Native spleen preservation in MMVT recipients attenuated the occurrence of GVHD and reduced the level of chimerism compared to recipients that underwent spleen removal during the transplant. Further experimental studies are warranted to clarify the mechanisms of the spleen immune effects over GVHD, chimerism and rejection; however, the results shown in this work strongly support the importance of this organ in the field of intestinal transplantation.

Modified Multivisceral Transplantation with Native Spleen Removal in Rats.

Modified multivisceral transplantation (MMVTx) refers to the use of a graft that includes all abdominal organs except the liver. The use of this type of transplant in children and adults expanded over the last years with good results. However, long-term survival in experimental models has not been reported. Our aim is to describe in detail some technical modifications of MMVTx to obtain long-term survival. Syngeneic (Lewis-Lewis) heterotopic MMVTx was performed in 16 male rats (180-250 g). All procedures were performed under isoflurane anesthesia. The graft consisted of stomach, duodenopancreatic axis, spleen, and small bowel. The vascular pedicle consisted of a conduit of aorta, including the celiac trunk and the superior mesenteric artery (SMA), and the portal vein (PV). The engraftment was performed by end-to-side anastomosis to the infra-renal cava vein and aorta. After reperfusion, the graft was accommodated in the right side of the abdomen, and a terminal ileostomy performed. The native spleen was removed. Donor and recipient time was 39 ± 4.4 minutes and 69 ± 7 minutes, respectively; venous and arterial anastomosis time was 14 ± 1 minutes and 12.3 ± 1 minutes, respectively. Total ischemia time was 77.2 ± 7.9 minutes. Survival was 75% (12/16), six were sacrificed after 2 hours, and six were kept alive for long-term evaluation (more than 1 week). Long-term survival is reported after heterotopic MMVTx in rats. The heterotopic MMVTx with native spleen removal would potentially improve the existent models for transplant research. The usefulness of this model warrants further confirmation in allogeneic experiments.

Native Spleen Removal and Modified Multivisceral Transplantation in Rats

[1]Aim: Various techniques and several modifications have been described for experimental intestinal transplantation. Modified multivisceral (MMV) graft offers the advantage of including all abdominal viscera with the corresponding immunologic load without the potential liver inclusion benefits. Our aim was to describe some technical modifications of MMV transplantation in rats with the addition of native splenectomy. Methods: Heterotopic syngeneic (Lewis-Lewis) MMV transplantations were performed in 5 pair of rats. Average weight of donors and recipients was 198± 10g and 250±14g respectively. Animals were operated under isoflurane inhalation anesthesia. Each graft consisted of the distal half of the stomach, duodenum, pancreas, spleen and the small bowel of the donor. The graft spleen was removed in the back table in two of them. Native intestine was preserved, avoiding the need of biliary reconstruction. The native spleen was removed. The vascular pedicle consisted of the celiac trunk and superior mesenteric artery with a cuff of aorta and the portal vein. Cold (4°C) Ringer’s solution with heparin (10 units/ml) was used to perfuse the vessels and irrigate the intestinal lumen. Venous outflow of the graft was reestablished first with end-to-side anastomoses between graft portal vein and recipient vena cava. Arterial revascularization was achieved by end-to-side arterial anastomoses between the cuff of the donor aorta and the recipient infrarenal aorta. Results: 4/5 recipients survived more than 1h after the procedure. One died due to arterial bleeding. All grafts showed adequate initial reperfusion, one showed mild congestion due to portal estenosis. Donor and recipient time were 37±7.7 min and 66.6±3.8 min respectively; venous anastomosis time was 14±3 min and arterial anastomosis time was 12±1 min. Conclusions: MMV offers an excellent experimental model. The lymphoid load can be modified with the inclusion of the graft spleen, and the removal of the native spleen is an original modification that improves the interest of this model for GVHD and other immunological studies. Reference: 1. Galvao F, et al. Transplant. 2013; 96 (2):e4-5.

Multivisceral Transplantation in Martinez-Frias Syndrome

Aim: Martinez-Frías Syndrome (MFS) is a very rare condition with autosomal recessive inheritance, firstly described in 1992. The most frequent patterns are hypoplastic pancreas, intestinal atresia and gallbladder aplasia/hipoplasia, probably due to a midline disorder affecting the development of the duodenal-biliary-pancreatic junction. Esophageal atresia and/or neonatal diabetes can be associated. There are few cases described in the literature, all with poor prognosis, mainly due to the progression of the liver disease. We present one girl with this condition who was succesfully transplanted. Case report: Female neonatal infant weighing 2200 g, 35 weeks of gestational age, with intrauterine growth retardation, and Spanish consanguineous gypsy parents. Physical examination did not show external abnormalities. A laparotomy due to intestinal obstruction was necessary within the first 24 hours of life, revealing duodenal atresia, intestinal malrotation type I, and gallbladder agenesia. Although surgery was uneventful, she developed refractory diabetes and pancreatic exocrine insufficiency, requiring parenteral nutrition for months with growth delay and multiple sepsis due to central line infections (12 episodes). The genetic study showed a mutation on 16q22.1 involving the gene RFX6. She was listed for multivisceral transplant, and was transplanted at 15 months of age, with no major postoperative complications. Her native spleen was preserved, and colon was included in the graft. The enterectomy revealed a patched substitution of the intestinal mucosa by gastric mucosa, and pancreatic hypoplasia with absence of islets and few neuroendocrine cells. Induction protocol consisted of Basiliximab, Tacrolimus with steroids were given for maintenance. Due to renal insufficiency and hypertension, conversion to Sirolimus was decided one year after transplantation, first combined with Tacrolimus, and later as monotherapy. After more than 5 years since transplant, the patient has not suffered any rejection, GVHD or PTLD episode. She is 6 yo, off parenteral nutrition, has a normal diet, with one bowel movement/day, with no malabsorption, just mild iron deficiency and enjoys a normal life. Conclusion: This is the longest survivor with MFS described in the literature. Multivisceral transplantation seems to be an available option for these children although future will determine if the disease is totally cured.FigureFigure

Epidermoid Cyst in an Intra-Pancreatic Accessory Spleen

The estimated prevalence of accessory spleen, most commonly found at the splenic hilum, is about 10% in the autopsy studies. The second commonly involved site is pancreas, and 1-2% of general population has intra-pancreatic accessory spleen (IPAS). Differential diagnosis of IPAS includes other solid pancreatic tumors, especially non-functioning pancreatic neuroendocrine tumors. Computed tomography scans and diffusion-weighted magnetic resonance imaging may accurately distinguish IPAS from other solid pancreatic lesions, with imaging features similar to the native spleen. Epidermoid cysts (EC) are common in the native spleen, but rarely found in IPAS. Differential diagnosis of the EC in IPAS includes other cystic lesions of the pancreas. Although the condition is extremely rare, an accurate pre-operative diagnosis can save a patient from major surgery given the benign nature of this condition. We present a case of an EC in an IPAS who underwent distal pancreatectomy with splenectomy for suspicion of malignancy.

Preservation of the native spleen in multivisceral transplantation

The native spleen is usually removed in patients undergoing MTV. The consequential asplenic state is associated with a high risk of sepsis, especially in immunosuppressed children. In contrast, the inclusion of an allogeneic spleen in multivisceral grafts has been associated with a high incidence of GVHD. We propose an alternative technique for patients undergoing MTV, consisting of the preservation of the native spleen. This approach avoids the additional risk of infection that characterizes the asplenic state without the detrimental side effects of the allogeneic spleen.

Technical aspects of intestinal transplantation

Intestinal transplantation includes an heterogeneous group of procedures in which different compositions of organs are transplanted. The current classification includes four groups according to the inclusion of the liver and/or the stomach in the graft: isolated intestinal transplantation, liver-intestinal transplantation, multivisceral transplantation, and modified multivisceral transplantation. Variants exist, the technical evolution having been slow, yet constant over years. The most relevant early technical improvements were aimed at achieving better feasibility and safety of the most difficult aspects of the different procedures, such as removal of the recipient's diseased organs, performing of vascular reconstructions and prevention of complications as with retention of the donor's duodenum and pancreas in liver-intestine transplantation. More recently, apart from a clear definition of the classification of the procedures, progress has been more directed in a conservative direction such as the preservation of the native spleen with and without the pancreas in multivisceral transplants. After achieving consistent satisfactory short-term results, the technical interest in intestinal transplantation is now moved to solutions that, in spite of a possible increased difficulty, may offer better opportunities of mid-term and long-term successes, both in terms of survival and quality of life.

A New Technique for Spleen Autotransplantation

Although the efficacy of spleen autotransplantation is debated, this approach remains the only possibility for preserving splenic function after traumatic splenectomy. This report describes an alternative method for splenic autotransplantation in case of splenic trauma. After splenectomy, the organ was weighed and the undamaged part was cut transversely to prepare a segment of approximately 4 × 3 × 2 cm in size and of 35 g of weight to be transplanted. The greater omentum was pedunculated in its left lateral portion, and the previously prepared splenic tissue was implanted in a pouch created at the lower edge of the omentum. The omental peduncle containing the splenic tissue was fixed to the parietal peritoneum of posterior left upper quadrant of the abdomen where the native spleen was previously located. This technique was performed in 4 patients after informed consent had been obtained. The functionality of the splenic implant was assessed after 3 months by abdominal computed tomography and scintigraphy. These exams showed the functioning of the trasplanted splenic tissue in all patients. This new technique needs further evaluation, but it appears to be an easy and safe alternative for spleen autotransplantation.