Helicobacter pylori-negative extra-nodal marginal zone B-cell lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) type following Roux-en-Y Gastric Bypass (RYGB).

Gastric MALT lymphoma is a common type of non-Hodgkin's lymphoma that has the potential for cure in patients found to have concomitant Helicobacter pylori (H. pylori) infection. This case report explores the evaluation, diagnosis, and treatment of H. pylori-negative MALT lymphoma in a patient with a history of a RYGB.

Re-endothelialization of rat lung scaffolds through passive, gravity-driven seeding of segment-specific pulmonary endothelial cells.

Effective re-endothelialization is critical for the use of decellularized scaffolds for ex vivo lung engineering. Current approaches yield insufficiently re-endothelialized scaffolds that haemorrhage and become thrombogenic upon implantation. Herein, gravity-driven seeding coupled with bioreactor culture facilitated widespread distribution and engraftment of endothelial cells throughout rat lung scaffolds. Initially, human umbilical vein endothelial cells were seeded into the pulmonary artery by either gravity-driven, variable flow perfusion seeding or pump-driven, pulsatile flow perfusion seeding. Gravity seeding evenly distributed cells and supported cell survival and re-lining of the vascular walls while perfusion pump-driven seeding led to increased cell fragmentation and death. Using gravity seeding, rat pulmonary artery endothelial cells and rat pulmonary vein endothelial cells attached in intermediate and large vessels, while rat pulmonary microvascular endothelial cells deposited mostly in microvessels. Combination seeding of these cells led to positive vascular endothelial cadherin staining. In addition, combination seeding improved barrier function as assessed by serum albumin extravasation; however, leakage was observed in the distal portions of the re-endothelialized tissue suggesting that recellularization of the alveoli is necessary to complete barrier function of the capillary-alveolar network. Overall, these data indicate that vascular recellularization of rat lung scaffolds is achieved through gravity seeding. Copyright © 2016 John Wiley & Sons, Ltd.

Characterization of an Acellular Scaffold for a Tissue Engineering Approach to the Nipple-Areolar Complex Reconstruction.

A significant number of patients undergo mastectomies and breast reconstructions every year using many surgical-based techniques to reconstruct the nipple-areolar complex (NAC). Described herein is a tissue engineering approach that may permit a human NAC onlay graft during breast reconstruction procedures. By applying decellularization, which is the removal of cellular components from tissue, to an intact whole donor NAC, the extracellular matrix (ECM) structure of the NAC is preserved. This creates a biologically derived scaffold for cells to repopulate and regenerate the NAC. A detergent-based decellularization method was used to derive whole NAC scaffolds from nonhuman primate rhesus macaque NAC tissue. Using both histological and quantitative analyses for the native and decellularized tissues, the derived ECM graft was assessed. The bioactivity of the scaffold was evaluated following cell culture with bone marrow-derived mesenchymal stem cells (BMSCs). The data presented here demonstrate that scaffolds are devoid of cells and retain ECM integrity and a high degree of bioactivity. The content of collagen and glycosaminoglycans were not significantly altered by the decellularization process, whereas the elastin content was significantly decreased. The proliferation and apoptosis of seeded BMSCs were found to be approximately 65 and <1.5%, respectively. This study characterizes the successful decellularization of NAC tissue as compared to native NACs based on structural protein composition, lubricating protein retention, the maintenance of adhesion molecules, and bioactivity when reseeded with cells. These histological and quantitative analyses provide the foundation for a novel approach to NAC reconstruction.