Seroconversion in liver and intestine transplant patients after one, two or three doses of adenoviral vector vaccines against SARS-CoV-2. Single center experience in Argentina.

BACKGROUND: The capacity of different anti-SARS-CoV-2 vaccines to elicit immune response is not equivalent in the healthy population compared to chronically immunosuppressed patients. Most of the reports available to assess the effects of anti-SARS-CoV-2 vaccines on solid organ transplant recipients (SOTR) were performed using mRNA-based vaccines. OBJECTIVE: This study aims to assess the seroconversion rate in a cohort of liver and liver- intestinal transplant patients after vaccination with the non-replicative vector-based vaccines after transplantation used in our country, Argentina (rAd26-rAd5 (Sputnik V) and ChAdOx11 nCoV-19 (AZD1222) (Astra Zeneca-Oxford). METHODS: One hundred and three (103) liver and liver-intestinal transplant recipients were enrolled. Patients with previous PCR-confirmed COVID19 were excluded, therefore 77 were finally included for analysis; 75 were liver transplant recipients, 1 was a combined liver-intestine and 1 a multivisceral transplant. All received their first vaccine dose between March and June 2021; 66,2% males, and the mean age was 56,3 years. All patients have a post-transplant follow up longer than 1 year (mean 6.6 years, median 5 years, range 1-23 years). Immune response after first, second and third doses were determined using three different spike (S)-S commercial ELISA kits and an in-house made anti nucleocapsid-protein (N) ELISA. RESULTS: Following the three doses, 57.1 % (44/77) of the patients seroconverted, while 33/77 (42.9 %) did not present anti-SARS-CoV-2 antibodies. The seroconversion rate was different for each dose. We found that 5/27 (18.5 %) of transplant patients seroconverted after a single dose; 18/29 pts (62.0 %) had anti-SARS-Cov-2 antibodies after the second doses; and 18/21 pts (85.7 %) reached the seroconversion after the third doses. The proportion of seroconversion was significantly increased in the second doses regardless the response observed after the first doses (p = 0.012, Fisher's exact test), particularly when two doses of ChAdOx11 vaccine was administrated (p = 0.040, Chi-square). However, the comparisons of seroconversion rate between Sputnik V and ChAdOx11 vaccines showed no differences after the different vaccination doses. No significant statistical difference in patient́s gender, age, comorbidities, type of vaccine, post-transplant, or maintenance immunosuppressive therapy was found between responders and non-responders. CONCLUSION: Despite having a lower seroconversion rate compared to the general population, viral-vector vaccines benefit SOTR patients increasing the seroconversion rate using at least two doses of vaccine. These results support the concept of developing tailor-made vaccination guidelines for this specific population. This analysis provides further support to safety and efficacy of viral-vector vaccines in liver and liver-intestine transplant patients.

Fallo intestinal crónico secundario a síndrome de intestino corto: papel actual de la cirugía, la rehabilitación médica y el trasplante intestinal. Informe evolutivo a 16 años de manejo multidisciplinario / Chronic intestinal failure due to short bowel syndrome: current role of surgery, medical rehabilitation, and intestinal transplantation. A progress report after 16 years of multidisciplinary management

RESUMEN Antecedentes: la insuficiencia intestinal, en su grado más grave, se conoce como fallo intestinal crónico (FIC). Las últimas décadas han sido testigo de la incorporación, evolución y perfeccionamiento de tratamientos que, en su conjunto, se denominan rehabilitación intestinal y abarcan tanto procedimientos quirúrgicos como tratamientos médicos que, llevados a cabo por equipos multi e interdisciplinarios, alcanzan altas tasas de éxito. Objetivo: describir los resultados de 16 años en el tratamiento de pacientes con FIC secundario a síndrome de intestino corto (SIC), y la evolución del papel de la cirugía, la rehabilitación médica y el trasplante. Material y métodos: análisis retrospectivo de una base de datos prospectiva de pacientes con fallo intestinal crónico secundario a SIC entre febrero de 2006 y marzo de 2022. Resultados: se incluyeron 492 pacientes (368 adultos-A y 124 pediátricos-P). Grupo A: 111 pacientes recibieron cirugía de reconstrucción autóloga del tracto gastrointestinal (CRATGI), 16 péptido semisintético similar al glucagón de tipo 2 (sGLP-2); el 83% logró la rehabilitación, con un 77% de supervivencia a 10 años; el 6,8% (17 pacientes) requirió trasplante intestinal (TxI), con un 89% de independencia de la nutrición parenteral (NP) al año y supervivencia post-TxI del 29% a los 10 años. Grupo B: 18 recibieron CRATGI; 9, enteroplastia serial transversa (STEP); y 6, sGLP-2; el 52% se rehabilitó, con una supervivencia del 69% a los 10 años; 28 pacientes recibieron TxI, con 69% de independencia de nutrición parenteral (NP) al año y supervivencia del 39% a los 10 años. Conclusión: los resultados presentados resaltan el papel central de la cirugía y la rehabilitación médica para alcanzar la suficiencia intestinal.

ABSTRACT Background: Severe intestinal insufficiency is known as chronic intestinal failure (CIF). In recent decades, medical treatments and surgical procedures have been incorporated, developed and improved under the name intestinal rehabilitation. When performed by multiand interdisciplinary teams, these treatments have high success rates. Objective: The aim of present study is to describe the 16-year outcomes in the management of patients with CIF secondary to short bowel syndrome (SBS) and the role of surgery, medical rehabilitation, and transplantation. Material and methods: We conducted a retrospective analysis on a prospective database of patients treated with chronic intestinal failure due to SBS between February 2006 and March 2022. Results: A total of 492 patients (368 adults (Group A) and 124 pediatric patients (Group B)] were included. Group A: 111 patients underwent autologous gastrointestinal reconstruction surgery (AGIRS), 16 were treated with semisynthetic glucagon-like peptide-2 (sGLP2); 83% achieved rehabilitation, with 77% survival at 10 years; 6.8% (17 patients) required intestinal transplantation (ITx), with 89% independence from parenteral nutrition (PN) at 1 year and post-ITx survival of 29% at 10 years. Group B: 18 patients underwent AGIRS; 9 underwent serial transverse enteroplasty (STEP); and 6 received sGLP2; 52% were rehabilitated, with 69% survival at 10 years; 28 patients received ITx, with 69% independence from PN at 1 year and 39% survival at 10 years. Conclusion: These results highlight the central role of surgery and medical rehabilitation in the recovery of intestinal function.

Cost-effectiveness of teduglutide in pediatric patients with short bowel syndrome: Markov modeling using traditional cost-effectiveness criteria.

BACKGROUND: Teduglutide use in pediatric patients with short bowel syndrome can aid in the achievement of enteral autonomy, but with a price of >$400,000 per y. OBJECTIVE: The current study evaluated the cost-effectiveness of using teduglutide in conjunction with offering intestinal transplantation in US pediatric patients with short bowel syndrome. DESIGN: A Markov model was used to evaluate the costs (in US dollars) and effectiveness [in quality-adjusted life years (QALYs)] of using teduglutide compared with offering intestinal transplantation. Parameters were estimated from published data where available. The primary effect modeled was the probability of weaning from parenteral nutrition while on teduglutide. Sensitivity analyses were performed on all model parameters. RESULTS: Compared with offering only intestinal transplantation, adding teduglutide cost ${\$}$124,353/QALY gained. Reducing the cost of the medication by 16% allowed the cost to reach the typical benchmark of ${\$}$100,000/QALY gained. Probabilistic sensitivity analysis favored transplantation without offering teduglutide in 68% of iterations at a ${\$}$100,000/QALY threshold. Never using teduglutide created an opportunity cost of over ${\$}$100,000 per patient. CONCLUSIONS: At its current price, teduglutide does not provide a cost-effective addition to transplantation in the treatment of pediatric short bowel syndrome. Further work should look to identify cost-reducing strategies, including alternative dosing regimens.

Results of Surgical and Medical Rehabilitation for Adult Patients With Type III Intestinal Failure in a Comprehensive Unit Today: Building a New Model to Predict Parenteral Nutrition Independency.

BACKGROUND: Short-bowel syndrome remains the primary cause of intestinal failure (IF) in adult patients. We aim to report the long-term results of medical and surgical rehabilitation in a cohort of patients with type III IF (III-IF) and develop a formula to predict parenteral nutrition (PN) independency. METHODS: We used a retrospective analysis of a prospective database for III-IF patients undergoing autologous gastrointestinal reconstruction surgery (AGIRS) from March 2006 to August 2018. Analyzed variables included demographic data, postsurgical intestinal length (PSIL), postsurgical anatomy, teduglutide (TED) treatment, and PN volume reduction. Univariate analysis, Cox regression, logistic regression forward stepwise models, and receiver operating characteristic (ROC) curve were done using SPSS v20. RESULTS: AGIRS was performed in 88 patients. The most frequent anatomy at first visit was type 1. Prevailing anatomy after surgery was type 3. Eight patients started TED; 6 achieved freedom from PN. At a mean follow-up time of 1606.1 ± 1190.25 days, freedom from PN survival was achieved in 83%. Variables identified at the logistic regression analysis led to a novel formula to predict intestinal rehabilitation, including PSIL, presence of ileocecal valve, and use of TED as part of postsurgical treatment. CONCLUSIONS: AGIRS in this group of patients enabled intestinal length increase and also intestinal anatomy conversion into a more favorable type for intestinal rehabilitation. TED treatment was useful to discontinue PN in patients with classical negative anatomical predictors. The novel predicting formula has an ROC area under the curve = 0.82. Further studies are necessary to validate this formula.

Meeting Report of the XIV International Small Bowel Transplant Symposium: Summary of Presentations, Workshops, and Debates From a Comprehensive Meeting on Intestinal Failure, Rehabilitation, and Transplantation, Buenos Aires, Argentina, June 10-13, 2015.

The 2015 meeting of the Intestinal Transplant Association was held in Buenos Aires, Argentina. This was the 14th International Small Bowel Transplant Symposium, and it was the first meeting organized as a joint venture of the Transplantation Society, the Intestinal Transplant Association, and the Argentinean Transplant Society (Sociedad Argentina de Trasplantes). Innovative aspects of the classic meeting format included workshops sessions, debates, and multicenter studies. This report highlights the most prominent scientific contributions and results of the first such symposium in a Latin American country.

[Laboratorial alteration preceding staphylococcal infection clinical manifestations after intestinal transplantation]. / Alteración laboratorial que precede a las manifestaciones clínicas de infección estafilocócica postrasplante intestinal.

BACKGROUND: Hospital-acquired infection, often with Staphylococcus aureus, is an important complication in intestinal transplant. CLINICAL CASE: A 2-year-old girl underwent small bowel transplantation owing to a small bowel volvulus. On the first postoperative day, lymphocyte phenotypes, serum immunoglobulins and chemotactic and phagocytic activity of neutrophils were assessed in peripheral blood. A decrease in the ingestion phase of phagocytosis by neutrophils was identified, in comparison with the results of 20 healthy children. On the second day, the patient had low fever and, on the third, abdominal pain. In view of this, she underwent a laparotomy that revealed purulent ascites due to Staphylococcus aureus. Specific treatment resulted in rapid regression of the infectious condition and good evolution of the patient. CONCLUSIONS: A decrease in the ingestion stage of phagocytosis by neutrophils preceded staphylococcal purulent ascites clinical manifestations, and immunologic assessment contributed to early diagnosis and treatment of the infection. We believe evaluation of neutrophilic activity is important in patients undergoing intestinal transplantation in order for possible hospital-acquired infections to be early diagnosed.

Antecedentes: La infección hospitalaria, frecuentemente por Staphylococcus aureus, es una complicación importante en los pacientes con trasplante intestinal. Caso clínico: Niña de 2 años de edad sometida a trasplante de intestino delgado debido a vólvulo yeyunal. En el primer día del posoperatorio, en la sangre periférica fueron evaluados fenotipo de linfocitos, inmunoglobulinas séricas, actividad quimiotáctica y fagocitaria de neutrófilos. Se identificó disminución de la etapa de ingestión de fagocitosis neutrofílica, en comparación con los resultados de 20 niños saludables. En el segundo día, la paciente presentó fiebre baja y en el tercero, dolor abdominal. Debido a lo anterior fue sometida a laparotomía que reveló ascitis purulenta por Staphylococcus aureus. El tratamiento específico derivó en regresión rápida del cuadro infeccioso y buena evolución. Conclusiones: La disminución de la etapa de ingestión de la fagocitosis neutrofílica precedió a las manifestaciones clínicas de ascitis purulenta estafilocócica; la evaluación inmunológica contribuyó al diagnóstico y tratamiento precoces de la infección. Creemos que es importante la evaluación de la actividad neutrofílica en pacientes sometidos a trasplante intestinal, con la finalidad de diagnosticar tempranamente posibles infecciones hospitalarias.

Utility of Aminotransferase/Platelet Ratio Index to Predict Liver Fibrosis in Intestinal Failure-Associated Liver Disease in Pediatric Patients.

BACKGROUND: Intestinal failure-associated liver disease (IFALD) is a frequent indication for intestinal transplantation. Liver biopsy (LBX) is the gold standard test for its diagnosis. Identifying noninvasive markers of fibrosis progression would be of considerable clinical use. Aspartate aminotransferase/platelet ratio index (APRI) has a good correlation in adult patients with chronic liver disease; few studies have been performed in children with IFALD. AIM: To evaluate APRI in a cohort of children with IFALD. MATERIALS AND METHODS: Retrospective analysis of a prospective database of patients <18 years with severe intestinal failure and at least 1 LBX, registered in our unit from March 2006 to December 2014. RESULTS: Forty-nine LBX were done on 36 patients: 20 were male, and 31 had short gut. Fibrosis was found in 71% of LBX. Biopsies were grouped according to the fibrosis stage (METAVIR [M]): (1) group 1 (G1) LBX with M 0, 1, 2 (n = 33) and (2) group 2 (G2) LBX with M 3, 4 (n = 16). The median APRI score was 0.92 (interquartile range [IQR] 0.63-1.50) for G1 and 2.50 (IQR 1.81-5.82) for G2 ( P = .001) The c statistic of the receiving operating characteristic curve was 0.79 (95% CI 0.64-0.94; P < .001). The analyses allowed identifying a cutoff value for APRI of 1.6 as the point with the best sensitivity (81%) and specificity (76%) to predict advanced fibrosis. CONCLUSIONS: APRI in this cohort of patients shows that a score >1.6 correlates with advanced fibrosis.

Immunosuppressive therapies after intestinal transplant modulate the expression of Th1 signature genes during acute cellular rejection. Implications in the search for rejection biomarkers.

BACKGROUND AND AIMS: Acute cellular rejection (ACR) and infections are leading causes of graft loss and death in intestinal transplant patients. Our aim was to evaluate the impact of maintenance immunosuppressive therapies on the expression of pro-inflammatory mediators in small bowel at ACR diagnosis. MATERIALS AND METHODS: We analyzed expression levels of Th1-associated genes, IFNG, CXCL10, and CXCL11 by qPCR in 46 selected graft biopsies unequivocally assigned to mild ACR (n = 14) or normal histopathology and clinical condition (n = 32) from 15 patients receiving two different immunosuppressive (IS) schemes. Double treatment: corticosteroids and tacrolimus (n = 17) and triple treatment: sirolimus or mycophenolate mofetil in addition to the basal therapy (n = 29). RESULTS: IFNG, CXCL10, and CXCL11 were induced during rejection (p < 0.05; p < 0.005, and p < 0.05, respectively). However, when rejection and control groups were classified according to immunosuppressive treatment, in the rejection group, significant differences of IFNG, CXCL10, and CXCL11 expression (p < 0.001; p < 0.005, and 0.01, respectively) were detected, whereas no differences were observed in the control group. CONCLUSION: Gene expression of Th1 response mediators is higher during ACR. Triple IS group showed significantly lower expression of pro-inflammatory Th1 mediators during mild ACR indicating that use of these markers to monitor rejection can be affected by the IS treatment used.

Trasplante intestinal en pediatría: análisis de la primera serie de receptores en la Argentina / Intestinal transplantation in pediatrics: analysis of the first recipient series in Argentina

El presente trabajo comunica la evolución posoperatoria inmediata y alejada de los pacientes pediátricos trasplantados en un único centro enla Argentina, desde marzo de 2006 hasta marzo de 2010, en variables demográficas, indicaciones, contraindicaciones, evolución y supervivencia de pacientes e injerto. Basándose en los resultados se puede concluir que el trasplante intestinal debe ser considerado como un tratamiento válido para todos aquellos pacientes que presenten insuficiencia intestinal,con complicaciones del soporte parenteral. Los resultados adquiridos en nuestro programa son similares a los comunicados internacionalmentey abren una nueva perspectiva para un grupo especial de niños que carecían de solución en nuestro medio.(AU)

The present is a retrospective analysis of all pediatric patients that underwent intestinal transplant from march 2006 to march 2010, describing demographics, indications, contraindications, clinical follow up and survival in a single center in Argentina. Based on the results shown one can conclude that intestinal transplant should be considered as a valid treatment for patients with intestinal insufficiency and complications related to parenteral nutrition. The results of our program are similar to those reported in the international Intestinal Transplant Registry. This opens a new perspective to a special population that otherwise would not have any other therapeutic option.(AU)

Trasplante intestinal en pediatría: análisis de la primera serie de receptores en la Argentina / Intestinal transplantation in pediatrics: analysis of the first recipient series in Argentina

El presente trabajo comunica la evolución posoperatoria inmediata y alejada de los pacientes pediátricos trasplantados en un único centro enla Argentina, desde marzo de 2006 hasta marzo de 2010, en variables demográficas, indicaciones, contraindicaciones, evolución y supervivencia de pacientes e injerto. Basándose en los resultados se puede concluir que el trasplante intestinal debe ser considerado como un tratamiento válido para todos aquellos pacientes que presenten insuficiencia intestinal,con complicaciones del soporte parenteral. Los resultados adquiridos en nuestro programa son similares a los comunicados internacionalmentey abren una nueva perspectiva para un grupo especial de niños que carecían de solución en nuestro medio.

The present is a retrospective analysis of all pediatric patients that underwent intestinal transplant from march 2006 to march 2010, describing demographics, indications, contraindications, clinical follow up and survival in a single center in Argentina. Based on the results shown one can conclude that intestinal transplant should be considered as a valid treatment for patients with intestinal insufficiency and complications related to parenteral nutrition. The results of our program are similar to those reported in the international Intestinal Transplant Registry. This opens a new perspective to a special population that otherwise would not have any other therapeutic option.

Valor crítico da citrulina para as complicações do enxerto no transplante de intestino / Critical value of citrulline for complications of intestinal transplant graft

OBJETIVO: Analisar, numa ampla amostra, o valor crítico da citrulina que confirma a presença das principais complicações do enxerto: rejeição e infecção. MÉTODOS: Foram coletadas 2135 amostras de citrulina sérica, na forma de gota de sangue seca, de 57 doentes submetidos a transplante de intestino/multivisceral no Jackson Memorial Hospital na Universidade de Miami, de março de 2004 a abril de 2006. Todas as amostras são do pós-operatório três meses em diante, passada a conhecida curva de elevação da citrulina após a recuperação das lesões causadas pela isquemia e reperfusão do pós-transplante. RESULTADOS: Utilizando um valor limite menor que 13 µmoles/L, a sensibilidade da citrulina foi de 96,4 por cento para detectar rejeicão celular aguda (RCA) moderada ou grave. A especificidade para as complicações mais freqüentes, rejeição e infecção foi de 54 por cento-74 por cento nas crianças e 83 por cento-88 por cento nos adultos, e o valor preditivo negativo (VPN) foi > 99 por cento. CONCLUSÃO: A citrulina pode ser utilizada como método não-invasivo para avaliar a evolução do enxerto intestinal após três meses do TI. Os episódios de RCA moderado e grave podem ser afastados quando o valor da citrulina for maior que 13 µmoles/L devido ao alto valor preditivo negativo.

OBJECITIVE: A biochemical marker for detection of acute cellular rejection following small intestine transplantation has been sought. Citrulline, a non- protein amino acid synthesized mainly by functioning enterocytes, has been proposed. Trial sensitivity has been reportedly high but with low specificity. Thus, the goal was to determine, in a sufficiently large analysis, the significant value of citrulline level in the post-transplant setting, which would correlate with complications such as rejection and infection. METHODS: Since March, 2004 2,135 dried blood spot (DBS) citrulline samples were obtained from 57 small intestine transplant recipients three months or more after post-transplant, i.e., once the expected period of recovery in the citrulline levels had occurred. RESULTS: Using a <13 vs. > 13 µmoles/L cut off point, sensitivity of DBS citrulline for the detection of moderate or severe ACR was extremely high (96.4 percent). Furthermore, specificity estimates (given the absence of ACR and these particular infections), while controlling for time-to-DBS sample were reasonably high (54 percent-74 percent in children and 83 percent-88 percent in adults), and the negative predictive value (NPV) was >99 percent. CONCLUSION: Citrulline is a non-invasive marker to evaluate problems of the intestinal graft after three months post-transplant. Due to the high NPV, a moderate or severe ACR can be ruled out, based exclusively on knowledge of a high value for DBS citrulline.

Graft versus host disease in a rat small bowel transplant model after T-cell depleted donor specific bone marrow infusion

Low cytoreductive regimen of irradiation associated to unmodified bone marrow infusion (UBM) does not prevent the occurrence of graft versus host disease (GVHD) after transplant. PURPOSE: In this study we evaluated the potential advantages of a long-term immunossupression and T-cell depleted bone marrow infusion (TCDBMI) in preventing the occurrence of GVHD after small bowel transplantation (SBTx). METHODS: Heterotopic SBTX was performed with Lewis rats as recipients and DA as donors and distributed into 5 groups according to the irradiation, duration of immunossupression and the use of UBM or TCDBMI: G1 (n=6), without irradiation and G2 (n=9), G3 (n=4), G4 (n=5) and G5 (n=6) was given 250 rd of irradiation. Groups 1,2,4 and G3 and 5 were infused with 100 x 10(6) UBM and TCDBM respectively. Animals in G1, 2, 3 were immunossupressed with 1mg/ FK506/Kg/IM for 5 days and G4 and G5 for 15 days. Anti CD3 monoclonal antibodies and immunomagnetic beads were used for T-cell depletion.Animals were examined for rejection, GVHD, chimerism characterization and ileal and skin biopsies. RESULTS: Minimal to mild rejection was observed in all groups; however, GVHD were present only in irradiated groups. Long-term immunossupression changed the severity of GVHD in G4 and G5. Rejection was the cause of death in G1 while GVHD in G2, 3, 4 and 5, not avoided by the use of TCDBMI. Total chimerism and T-cell chimerism was statistically higher in irradiated groups when compared to G1. CONCLUSION: Extended immunossupression associated to low dose of irradiation decrease the severity of GVHD, not avoided by the use of TCDBMI.

Baixas doses de irradiação associadas à infusão de células da medula óssea não previnem a ocorrência da reação do enxerto versus hospedeiro após o transplante intestinal. OBJETIVO: Neste estudo foi avaliado a potencial vantagem em estender o regime imunossupressor associado a infusão de células de medula óssea do doador depletadas de células T na prevenção da reação do enxerto versus hospedeiro após o transplante intestinal. MÉTODOS: Transplante heterotópico de intestino delgado foi realizado em ratos Lewis como receptores e DA como doadores, distribuídos em cinco grupos de acordo com a duração da imunossupressão, irradiação e do uso de medula óssea normal ou depletada: G1 (n=6), sem irradiação e G2 (n=9), G3 (n=4), G4 (n=5) e G5 (n=6) foram irradiados com 250 rd. Grupos1, 2, 4 e G3 e 5 foram infundidos com 100 x 10(6) células da medula normal e depletada respectivamente. Animais no G1,2,3 foram imunossuprimidos com 1mg/kg/FK506/ IM por cinco dias e G4 e cinco por 15 dias. Anticorpos monoclonais contra células CD3 e colunas magnéticas foram utilizadas para a depleção da medula óssea. Os animais foram examinados para a presença de rejeição, reação do enxerto versus hospedeiro, chimerismo e biópsias intestinais e da pele. RESULTADOS: Rejeição mínima foi observada em todos os grupos; entretanto, a reação do enxerto versus hospedeiro somente nos animais irradiados. Extensão da imunossupressão alterou a gravidade da reação nos animais dos G4 e 5. Rejeição foi a causa mortis no G1 e a reação do enxerto versus hospedeiro nos Grupos 2,3,4 e 5, não controlada com a infusão de medula óssea depletada. O chimerismo total e de células T do doador foi estatisticamente maior nos grupos irradiados em comparação ao G1. CONCLUSÃO: A extensão do regime de imunossupressão associado a baixas doses de irradiação diminui a gravidade da reação do enxerto versus hospedeiro, não abolida pelo uso de medula óssea depletada.

Chimerism induction by nonmyeloablactive preconditioning and bone marrow infusion in rat small bowel transplantation

In our previous work we demonstrated that the use of donor specific bone marrow infusions ( DSBMI ) after small bowel transplantation did not improve the graft survival after a short course of immunossupression. PURPOSE: In the current study, we evaluated whether recipient preconditioning with different regimens of radiation combined with DSBMI may enhance small bowel allograft survival with minimum recipient morbidity. METHODS: Heterotopic small bowel transplantation (SBTx) was performed with Lewis rats as recipients and DA rats as donors, which were immunossupressed with a short course of tacrolimus (FK 506 ) at 1mg/Kg/day for 5 days and distributed in 4 groups: group 1 (n= 4) without both irradiation and DSBMI; Groups 2 (n= 6), 3 (n= 9) and 4 (n= 6) received 100 x 10(6) DSBM cells at the time of the transplant. Groups 3 and 4 were irradiated with 250 and 400 rd respectively. Animals were examined daily for clinical signs of rejection or GVHD. Blood samples were taken weekly for chimeric studies by FC and intestinal biopsies were performed every 2 weeks. RESULTS: Animals in G1 and G2 had minimal rejection at day 15 after SBTx while GVHD was clinically and histologically characterized in G 3 and G 4. Total chimerism and T-cell chimerism was higher in irradiated groups when compared to non-irradiated groups. With exception of G1 and 2 where rejection was the cause of death, all animals in G3 and 4 died of GVHD. CONCLUSION:We concluded that low cytoreductive of irradiation can successfully decrease the graft rejection but not prevent the occurrence of GVHD.

Em estudo recente demonstramos que a infusão de células da medula óssea do doador após o transplante intestinal não aumentou a sobrevida do enxerto quando se utilizou series curtas de drogas imunossupressoras. OBJETIVO: Neste estudo avaliamos se a utilização de diferentes regimes de irradiação em associação com a infusão de medula óssea altera a sobrevida do enxerto e a morbidade sobre receptor. MÉTODOS: Realizou-se o transplante heterotópico de intestino delgado, utilizando-se ratos Lewis como receptores e DA como doadores, imunossuprimidos com FK 506 na dose de 1mg/kg/dia por 5 dias e distribuídos em 4 grupos: G1 (n= 4), não irradiado e sem infusão de medula óssea; G2 (n= 6), G3 (n= 9) e G4 (n= 6) foram infundidos com 100 x 10(6) células de medula após o transplante. Grupos 3 e 4 foram irradiados com 250 e 400 rd respectivamente. Os animais foram examinados diariamente para a detecção de rejeição e reação do enxerto versus hospedeiro, tendo sido colhidas amostras semanais de sangue para estudos de quimerismose biopsias quinzenais da estomia. RESULTADOS: Animais nos G1 e G2 apresentaram rejeição mínima no 15º pós-operatório, enquanto a reação do enxerto versus hospedeiro foi caracterizada nos G3 e G4. Os níveis de quimerismo total e de células T foram maiores nos grupos irradiados em comparação aos não irradiados. A causa mortis nos G1 e G2 foi a rejeição enquanto que nos G3 e G4 foi a reação do enxerto versus hospedeiro. CONCLUSÃO: Concluímos que a utilização de baixas doses de irradiações retardam o aparecimento da rejeição, mas não previne a ocorrência da reação do enxerto versus hospedeiro.