Clinical Outcomes in Delayed Sternal Closure in Lung Transplantation.

Introduction: Lung transplantation (LTx) is a critical treatment for end-stage pulmonary diseases. Delayed sternal closure (DSC) has been noted in cardiac surgery for several decades and is a viable strategy for patients who are hemodynamically unstable, at high risk for postoperative bleeding, and/or require prolonged cardiopulmonary bypass. However, DSC use and its effects on LTx clinical outcomes are not well-defined.

Impact of Difficult Lung Transplantation on Short-Term and Long-Term Survival.

Background: Lung transplantation (LTx) is a complex operation; however, certain factors can make LTx even more challenging. A difficult LTx could adversely affect immediate and long-term outcomes. We investigate the potential use of Modifier-22 to identify difficult LTx to evaluate postoperative outcomes.

Porous Precision-Templated 40 μm Pore Scaffolds Promote Healing through Synergy in Macrophage Receptor with Collagenous Structure and Toll-Like Receptor Signaling.

Porous precision-templated scaffolds (PTS) with uniform, interconnected, 40 μm pores have shown favorable healing outcomes and a reduced foreign body reaction (FBR). Macrophage receptor with collagenous structure (MARCO) and toll-like receptors (TLRs) have been identified as key surface receptors in the initial inflammatory phase of wound healing. However, the role of MARCO and TLRs in modulating monocyte and macrophage phenotypes within PTS remains uncharacterized.

Novel HALO® image analysis to determine cell phenotype in porous precision-templated scaffolds.

Image analysis platforms have gained increasing popularity in the last decade for the ability to automate and conduct high-throughput, multiplex, and quantitative analyses of a broad range of pathological tissues. However, imaging tissues with unique morphology or tissues containing implanted biomaterial scaffolds remain a challenge. Using HALO®, an image analysis platform specialized in quantitative tissue analysis, we have developed a novel method to determine multiple cell phenotypes in porous precision-templated scaffolds (PTS).

Monocytes contribute to a pro-healing response in 40 μm diameter uniform-pore, precision-templated scaffolds.

Porous precision-templated scaffolds (PTS) with uniformly distributed 40 μm spherical pores have shown a remarkable ability in immunomodulating resident cells for tissue regeneration. While the pore size mediated pro-healing response observed only in 40 μm pore PTS has been attributed to selective macrophage polarization, monocyte recruitment and phenotype have largely been uncharacterized in regulating implant outcome. Here, we employ a double transgenic mouse model for myeloid characterization and a multifaceted phenotyping approach to quantify monocyte dynamics within subcutaneously implanted PTS.

Potential role of exosome-based allorecognition pathways involved in lung transplant rejection.

Innate and adaptive immunity both contribute to allorecognition mechanisms that drive rejection after lung transplantation. Classic allorecognition pathways have been extensively described, but there continues to be several unanswered questions. Exosome research appears to be a novel and potentially significant area of allorecognition research and could be the missing link that answers some existing questions.

Uniform 40-µm-pore diameter precision templated scaffolds promote a pro-healing host response by extracellular vesicle immune communication.

Implanted porous precision templated scaffolds (PTS) with 40-µm spherical pores reduce inflammation and foreign body reaction (FBR) while increasing vascular density upon implantation. Larger or smaller pores, however, promote chronic inflammation and FBR. While macrophage (MØ) recruitment and polarization participates in perpetuating this pore-size-mediated phenomenon, the driving mechanism of this unique pro-healing response is poorly characterized.

Prediction Model for Nodal Disease Among Patients With Non-Small Cell Lung Cancer.

Background: We characterized the performance characteristics of guideline-recommended invasive mediastinal staging (IMS) for lung cancer and developed a prediction model for nodal disease as a potential alternative approach to staging.

Methods: We conducted a prospective cohort study of adults with suspected/confirmed non-small cell lung cancer without evidence of distant metastatic disease (by computed tomography/positron emission tomography) who underwent nodal evaluation by IMS and/or at the time of resection. The true-positive rate was the proportion of patients with true nodal disease selected to undergo IMS based on guideline recommendations, and the false-positive rate was the proportion of patients without true nodal disease selected to undergo IMS.

Challenges in Predicting Recurrence After Resection of Node-Negative Non-Small Cell Lung Cancer.

Background: One in 5 patients with completely resected early-stage non-small cell lung cancer will recur within 2 years. Risk stratification may facilitate a personalized approach to the use of adjuvant therapy and surveillance imaging. We developed a prediction model for recurrence based on five clinical variables (tumor size and grade, visceral pleural and lymphovascular invasion, and sublobar resection), and tested the hypothesis that the addition of several new molecular markers of poor long-term outcome (vascular endothelial growth factor C; microRNA precursors 486 and 30d) would enhance prediction.

Multispectral Optical Tweezers for Biochemical Fingerprinting of CD9-Positive Exosome Subpopulations.

Extracellular vesicles (EVs), including exosomes, are circulating nanoscale particles heavily implicated in cell signaling and can be isolated in vast numbers from human biofluids. Study of their molecular profiling and materials properties is currently underway for purposes of describing a variety of biological functions and diseases. However, the large, and as yet largely unquantified, variety of EV subpopulations differing in composition, size, and likely function necessitates characterization schemes capable of measuring single vesicles.

Pretreatment with bone marrow-derived mesenchymal stromal cell-conditioned media confers pulmonary ischemic tolerance.

Objective: Mesenchymal stromal cell-based therapies have demonstrated efficacy in treating a variety of diseases. Despite the potential benefits, there are still significant hurdles that need to be overcome for clinical use. We describe a cell-free-based immunotherapy approach for inducing pulmonary ischemic tolerance by using mesenchymal stromal cell-conditioned media.

Validating the use of short interfering RNA as a novel technique for cell-specific target gene knockdown in lung ischemia-reperfusion injury.

Objective: Short interfering RNA is an effective method for target gene knockdown. However, concerns surround the design, administration, efficacy, specificity, and immunostimulatory potential. Although uptake by alveolar macrophages has been demonstrated, studies have not examined its use in lung ischemia-reperfusion injury.

Vascular endothelial growth factor C complements the ability of positron emission tomography to predict nodal disease in lung cancer.

Objective: Vascular endothelial growth factors (VEGFs) C and D are biologically rational markers of nodal disease that could improve the accuracy of lung cancer staging. We hypothesized that these biomarkers would improve the ability of positron emission tomography (PET) to predict nodal disease among patients with suspected or confirmed non-small cell lung cancer (NSCLC).

Methods: A cross-sectional study (2010-2013) was performed of patients prospectively enrolled in a lung nodule biorepository, staged by computed tomography (CT) and PET, and who underwent pathologic nodal evaluation.

Differential toll-like receptor activation in lung ischemia reperfusion injury.

Objective: The requirement for toll-like receptors (TLRs) in lung ischemia reperfusion injury (LIRI) has been demonstrated but not fully characterized. Previously, we reported that TLR-4 is required by alveolar macrophages but not pulmonary endothelial or epithelial cells for development of LIRI. Additionally, we demonstrated differential patterns of mitogen-activated protein kinase (MAPK) activation and cytokine release in these cell types during LIRI.

Role of toll-like receptor-4 in lung ischemia-reperfusion injury.

Background: Toll-like receptor-4 has been implicated in modulating ischemia-reperfusion injury in cardiac, hepatic, renal, and cerebral models. However, its role in lung ischemia-reperfusion injury is unknown. We hypothesize that toll-like receptor-4 has a key role in initiating the inflammatory cascade in lung ischemia-reperfusion injury.

Simultaneous transplantation of hematopoietic stem cells and a vascularized composite allograft leads to tolerance.

Background: We have previously demonstrated that tolerance to a vascularized composite allograft (VCA) can be achieved after the establishment of mixed chimerism. We test the hypothesis that tolerance to a VCA in our dog leukocyte antigen-matched canine model is not dependent on the previous establishment of mixed chimerism and can be induced coincident with hematopoietic cell transplantation (HCT).

Methods: Eight dog leukocyte antigen-matched, minor antigen mismatched dogs received 200 cGy of radiation and a VCA transplant.

Tolerance to vascularized composite allografts in canine mixed hematopoietic chimeras.

Background: Mixed donor-host chimerism, established through hematopoietic cell transplantation (HCT), is a reproducible strategy for the induction of tolerance toward solid organs. Here, we ask whether a nonmyeloablative conditioning regimen establishing mixed donor-host chimerism leads to tolerance of antigenic vascularized composite allografts.

Methods: Stable mixed chimerism was established in dogs given a sublethal dose (1-2 Gy) total body irradiation before and a short course of immunosuppression after dog leukocyte antigen-identical marrow transplantation.

Antagonistic and agonistic anti-canine CD28 monoclonal antibodies: tools for allogeneic transplantation.

Background: It has been presumed that antibody-mediated selective costimulatory molecule blockade of CD28 is superior to cytotoxic T lymphocyte antigen 4 (CTLA4)-Ig. This is based on the premise that specifically blocking CD28 allows inhibitory signals through CTLA-4 to proceed, which furthermore suppresses T-cell function.

Methods: The extracelluar domain of canine (ca)CD28 was cloned from dog peripheral blood mononuclear cells.

Mesenchymal stromal cells fail to prevent acute graft-versus-host disease and graft rejection after dog leukocyte antigen-haploidentical bone marrow transplantation.

Mesenchymal stromal cells (MSCs) have been shown to have immunosuppressive effects in vitro. To test the hypothesis that these effects can be harnessed to prevent graft-versus-host disease (GVHD) and graft rejection after hematopoietic cell transplantation (HCT), we administered a combination of 3 different immortalized marrow-derived MSC lines (15-30 × 10⁶ MSCs/kg/day, 2-5 times/week) or third-party primary MSC (1.0 × 10⁶ MSCs/kg/day, 3 times/week) to canine recipients (n = 15) of dog leukocyte antigen-haploidentical marrow grafts prepared with 9.

A novel monoclonal antibody specific for canine CD25 (P4A10): selection and evaluation of canine Tregs.

A monoclonal antibody (mAb), P4A10, was made to the canine interleukin-2 receptor alpha chain (IL-2Ralpha; p55; Tac antigen; CD25) to facilitate studies of canine regulatory T-cells (Treg). By non-reduced Western blot, P4A10 bound to a 55kDa protein, the size of human IL-2Ralpha. In flow cytometry assays, it reacted with a minor population of circulating dog CD3(+)CD4(+) T-cells and the majority (>60%) of in vitro PMA-Ionomycin (PMA-IO)-activated canine CD3(+) T-cells.

Intussusception in canine recipients of hematopoietic cell grafts and surgical correction.

Intussusception is a common complication after canine hematopoietic cell transplantation (HCT). The present study was undertaken to evaluate predisposing factors of intussusception and to test whether intussusception can be managed surgically during the period immediately after HCT. We determined the incidence of intussusception after HCT was performed in 325 canine recipients (autologous, n = 43; allogeneic, n = 282) during the interval from January 2002 to May 2005.

Partial donor-specific tolerance to delayed skin grafts after rejection of hematopoietic cell graft.

Background: Donor-specific tolerance (DST) is induced after allogeneic hematopoietic cell transplantation (HCT) and is a potential strategy for prolonging survival of solid organ grafts. DST may persist in recipients with transient mixed hematopoietic chimerism (MC) when solid organ transplantation and HCT are done concomitantly.

Methods: In a canine model of allogeneic HCT after nonmyeloablative conditioning, DST to skin grafts was evaluated in dog leukocyte antigen (DLA)-identical recipients with stable MC (n=11), or after rejection of the hematopoietic cell (HC) graft (n=19).