Decellularized Splenic Matrix as a Scaffold for Spleen Bioengineering.

The spleen is considered a non-essential organ. However, its importance is increasingly clear, given the serious disorders caused by its absence or dysfunction, e.g., greater susceptibility to infections, thromboembolism and cancer. Surgical techniques to preserve the spleen and maintain splenic function have become increasingly common. However, the morbidity and mortality associated with its absence and dysfunction are still high. We used the decellularization technique to obtain a viable splenic scaffold for recellularization in vitro and propose the idea of bioengineered spleen transplantation to the host. We observed the maintenance of important structural components such as white pulp, marginal zone and red pulp, in addition to the network of vascular ducts. The decellularized scaffold presents minimal residual DNA and SDS, which are essential to prevent immunogenic responses and transplantation failure. Also, the main components of the splenic matrix were preserved after decellularization, with retention of approximately 72% in the matrisomal protein content. The scaffold we developed was partially recellularized with stromal cells from the spleen of neonatal rats, demonstrating adhesion, proliferation and viability of cells. Therefore, the splenic scaffold is very promising for use in studies on spleen reconstruction and transplantation, with the aim of complete recovery of splenic function.

Decellularized splenic matrix as a scaffold for spleen bioengineering

The spleen is considered a non-essential organ. However, its importance is increasingly clear, given the serious disorders caused by its absence or dysfunction, e.g., greater susceptibility to infections, thromboembolism and cancer. Surgical techniques to preserve the spleen and maintain splenic function have become increasingly common. However, the morbidity and mortality associated with its absence and dysfunction are still high. We used the decellularization technique to obtain a viable splenic scaffold for recellularization in vitro and propose the idea of bioengineered spleen transplantation to the host. We observed the maintenance of important structural components such as white pulp, marginal zone and red pulp, in addition to the network of vascular ducts. The decellularized scaffold presents minimal residual DNA and SDS, which are essential to prevent immunogenic responses and transplantation failure. Also, the main components of the splenic matrix were preserved after decellularization, with retention of approximately 72% in the matrisomal protein content. The scaffold we developed was partially recellularized with stromal cells from the spleen of neonatal rats, demonstrating adhesion, proliferation and viability of cells. Therefore, the splenic scaffold is very promising for use in studies on spleen reconstruction and transplantation, with the aim of complete recovery of splenic function.

Advances in the Knowledge about Kidney Decellularization and Repopulation.

End-stage renal disease (ESRD) is characterized by the progressive deterioration of renal function that may compromise different tissues and organs. The major treatment indicated for patients with ESRD is kidney transplantation. However, the shortage of available organs, as well as the high rate of organ rejection, supports the need for new therapies. Thus, the implementation of tissue bioengineering to organ regeneration has emerged as an alternative to traditional organ transplantation. Decellularization of organs with chemical, physical, and/or biological agents generates natural scaffolds, which can serve as basis for tissue reconstruction. The recellularization of these scaffolds with different cell sources, such as stem cells or adult differentiated cells, can provide an organ with functionality and no immune response after in vivo transplantation on the host. Several studies have focused on improving these techniques, but until now, there is no optimal decellularization method for the kidney available yet. Herein, an overview of the current literature for kidney decellularization and whole-organ recellularization is presented, addressing the pros and cons of the actual techniques already developed, the methods adopted to evaluate the efficacy of the procedures, and the challenges to be overcome in order to achieve an optimal protocol.

PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENTOF DUMPING SYNDROME AND ITS RELATION TO BARIATRIC SURGERY.

Introduction: The dumping syndrome is frequent in bariatric surgery. It is probably the most common syndrome following partial or complete gastrectomy. Its prevalence in partial gastrectomy can reach up to 50%, thus it can be a significant complication arising from some types of bariatric surgeries. Objective: Critical analysis on dumping syndrome, its pathophysiology, diagnosis and treatment. Methods: A literature review was performed using the key words: 'dumping syndrome', 'bariatric surgery' and 'rapid dumping syndrome'. Inclusion criteria were: books, original works, case reports and meta-analyzes, and the exclusion criterion was literature review. Concerning the publication time, articles were screened between 1960 and May 2015. Results: The dumping syndrome is complication arising from obesity surgeries, but also can be a result of vagus nerve damage. Diagnosis is done primarily through the use of questionnaires based on scores. Conclusion: The Sigstad score and Arts survey are valid means for assessing the dumping syndrome. Initial therapy consists in the adoption of dietary measures, short acting drugs administration.

Introdução: A síndrome de dumping é frequente após operações bariátricas. É, provavelmente, a mais comum das síndromes que sucedem gastrectomias parciais ou completas. Sua prevalência, em gastrectomias parciais pode chegar a até 50%, tornando-se assim complicação significante em alguns tipos de operações bariátricas. Objetivo: Realizar análise crítica sobre a síndrome de dumping em sua fisiopatologia, diagnóstico e tratamento. Métodos: Foi realizada revisão bibliográfica utilizando os descritores: 'síndrome de dumping', 'cirurgia bariátrica' e 'síndrome do esvaziamento rápido'. Os critérios de inclusão foram: livros, trabalhos originais, relatos de caso e metanálises; excluíram-se as revisões bibliográficas. Quanto ao tempo de publicação, foram selecionados artigos entre 1960 e maio de 2015. Resultados: A síndrome de dumping é complicação gastrointestinal oriunda de operações para obesidade, mas também pode ocasionar-se como consequência de danos no nervo vago. Seu diagnóstico é realizado primordialmente através da aplicação de questionários baseados em pontuações. Conclusão: O escore de Sigstad e questionário de Arts são meios válidos para avaliação da síndrome de dumping. A terapia inicial consiste na adoção de medidas dietéticas, ou fármacos administráveis de ação curta.

PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENTOF DUMPING SYNDROME AND ITS RELATION TO BARIATRIC SURGERY / FISIOPATOLOGIA, DIAGNÓSTICO E TRATAMENTO DA SÍNDROME DE DUMPING E SUA RELAÇÃO COM A CIRURGIA BARIÁTRICA

ABSTRACT Introduction The dumping syndrome is frequent in bariatric surgery. It is probably the most common syndrome following partial or complete gastrectomy. Its prevalence in partial gastrectomy can reach up to 50%, thus it can be a significant complication arising from some types of bariatric surgeries. Objective: Critical analysis on dumping syndrome, its pathophysiology, diagnosis and treatment. Methods: A literature review was performed using the key words: 'dumping syndrome', 'bariatric surgery' and 'rapid dumping syndrome'. Inclusion criteria were: books, original works, case reports and meta-analyzes, and the exclusion criterion was literature review. Concerning the publication time, articles were screened between 1960 and May 2015. Results: The dumping syndrome is complication arising from obesity surgeries, but also can be a result of vagus nerve damage. Diagnosis is done primarily through the use of questionnaires based on scores. Conclusion: The Sigstad score and Arts survey are valid means for assessing the dumping syndrome. Initial therapy consists in the adoption of dietary measures, short acting drugs administration.

RESUMO Introdução: A síndrome de dumping é frequente após operações bariátricas. É, provavelmente, a mais comum das síndromes que sucedem gastrectomias parciais ou completas. Sua prevalência, em gastrectomias parciais pode chegar a até 50%, tornando-se assim complicação significante em alguns tipos de operações bariátricas. Objetivo: Realizar análise crítica sobre a síndrome de dumping em sua fisiopatologia, diagnóstico e tratamento. Métodos: Foi realizada revisão bibliográfica utilizando os descritores: 'síndrome de dumping', 'cirurgia bariátrica' e 'síndrome do esvaziamento rápido'. Os critérios de inclusão foram: livros, trabalhos originais, relatos de caso e metanálises; excluíram-se as revisões bibliográficas. Quanto ao tempo de publicação, foram selecionados artigos entre 1960 e maio de 2015. Resultados: A síndrome de dumping é complicação gastrointestinal oriunda de operações para obesidade, mas também pode ocasionar-se como consequência de danos no nervo vago. Seu diagnóstico é realizado primordialmente através da aplicação de questionários baseados em pontuações. Conclusão: O escore de Sigstad e questionário de Arts são meios válidos para avaliação da síndrome de dumping. A terapia inicial consiste na adoção de medidas dietéticas, ou fármacos administráveis de ação curta.