Altered brain metabolites in male nonhuman primate offspring exposed to maternal immune activation.

Converging data show that exposure to maternal immune activation (MIA) in utero alters brain development in animals and increases the risk of neurodevelopmental disorders in humans. A recently developed non-human primate MIA model affords opportunities for studies with uniquely strong translational relevance to human neurodevelopment. The current longitudinal study used 1H-MRS to investigate the developmental trajectory of prefrontal cortex metabolites in male rhesus monkey offspring of dams (n = 14) exposed to a modified form of the inflammatory viral mimic, polyinosinic:polycytidylic acid (Poly IC), in the late first trimester. Brain metabolites in these animals were compared to offspring of dams that received saline (n = 10) or no injection (n = 4). N-acetylaspartate (NAA), glutamate, creatine, choline, myo-inositol, taurine, and glutathione were estimated from PRESS and MEGA-PRESS acquisitions obtained at 6, 12, 24, 36, and 45 months of age. Prior investigations of this cohort reported reduced frontal cortical gray and white matter and subtle cognitive impairments in MIA offspring. We hypothesized that the MIA-induced neurodevelopmental changes would extend to abnormal brain metabolite levels, which would be associated with the observed cognitive impairments. Prefrontal NAA was significantly higher in the MIA offspring across all ages (p < 0.001) and was associated with better performance on the two cognitive measures most sensitive to impairment in the MIA animals (both p < 0.05). Myo-inositol was significantly lower across all ages in MIA offspring but was not associated with cognitive performance. Taurine was elevated in MIA offspring at 36 and 45 months. Glutathione did not differ between groups. MIA exposure in male non-human primates is associated with altered prefrontal cortex metabolites during childhood and adolescence. A positive association between elevated NAA and cognitive performance suggests the hypothesis that elevated NAA throughout these developmental stages reflects a protective or resilience-related process in MIA-exposed offspring. The potential relevance of these findings to human neurodevelopmental disorders is discussed.

Stem cells, cell therapies, and bioengineering in lung biology and diseases 2023.

Repair and regeneration of a diseased lung using stem cells or bioengineered tissues is an exciting therapeutic approach for a variety of lung diseases and critical illnesses. Over the past decade, increasing evidence from preclinical models suggests that mesenchymal stromal cells, which are not normally resident in the lung, can be used to modulate immune responses after injury, but there have been challenges in translating these promising findings to the clinic. In parallel, there has been a surge in bioengineering studies investigating the use of artificial and acellular lung matrices as scaffolds for three-dimensional lung or airway regeneration, with some recent attempts of transplantation in large animal models. The combination of these studies with those involving stem cells, induced pluripotent stem cell derivatives, and/or cell therapies is a promising and rapidly developing research area. These studies have been further paralleled by significant increases in our understanding of the molecular and cellular events by which endogenous lung stem and/or progenitor cells arise during lung development and participate in normal and pathological remodeling after lung injury. For the 2023 Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases Conference, scientific symposia were chosen to reflect the most cutting-edge advances in these fields. Sessions focused on the integration of "omics" technologies with function, the influence of immune cells on regeneration, and the role of the extracellular matrix in regeneration. The necessity for basic science studies to enhance fundamental understanding of lung regeneration and to design innovative translational studies was reinforced throughout the conference.

RBL2 represses the transcriptional activity of Multicilin to inhibit multiciliogenesis.

A core pathophysiologic feature underlying many respiratory diseases is multiciliated cell dysfunction, leading to inadequate mucociliary clearance. Due to the prevalence and highly variable etiology of mucociliary dysfunction in respiratory diseases, it is critical to understand the mechanisms controlling multiciliogenesis that may be targeted to restore functional mucociliary clearance. Multicilin, in a complex with E2F4, is necessary and sufficient to drive multiciliogenesis in airway epithelia, however this does not apply to all cell types, nor does it occur evenly across all cells in the same cell population. In this study we further investigated how co-factors regulate the ability of Multicilin to drive multiciliogenesis. Combining data in mouse embryonic fibroblasts and human bronchial epithelial cells, we identify RBL2 as a repressor of the transcriptional activity of Multicilin. Knockdown of RBL2 in submerged cultures or phosphorylation of RBL2 in response to apical air exposure, in the presence of Multicilin, allows multiciliogenesis to progress. These data demonstrate a dynamic interaction between RBL2 and Multicilin that regulates the capacity of cells to differentiate and multiciliate. Identification of this mechanism has important implications for facilitating MCC differentiation in diseases with impaired mucociliary clearance.

Alveolar type I cells can give rise to KRAS-induced lung adenocarcinoma.

Lung adenocarcinoma (LUAD) is the most prevalent subtype of lung cancer and presents clinically with a high degree of biological heterogeneity and distinct clinical outcomes. The current paradigm of LUAD etiology posits alveolar epithelial type II (AT2) cells as the primary cell of origin, while the role of AT1 cells in LUAD oncogenesis remains unknown. Here, we examine oncogenic transformation in mouse Gram-domain containing 2 (Gramd2)+ AT1 cells via oncogenic KRASG12D. Activation of KRASG12D in AT1 cells induces multifocal LUAD, primarily of papillary histology. Furthermore, KRT8+ intermediate cell states were observed in both AT2- and AT1-derived LUAD, but SCGB3A2+, another intermediate cell marker, was primarily associated with AT1 cells, suggesting different mechanisms of tumor evolution. Collectively, our study reveals that Gramd2+ AT1 cells can serve as a cell of origin for LUAD and suggests that distinct subtypes of LUAD based on cell of origin be considered in the development of therapeutics.

Sorafenib inhibits invasion of multicellular organoids that mimic Lymphangioleiomyomatosis nodules.

Lymphangioleiomyomatosis (LAM) is a debilitating, progressive lung disease with few therapeutic options, largely due to a paucity of mechanistic knowledge of disease pathogenesis. Lymphatic endothelial cells (LECs) are known to envelope and invade clusters of LAM-cells, comprising of smooth muscle α-actin and/or HMB-45 positive "smooth muscle-like cells" however the role of LECs in LAM pathogenesis is still unknown. To address this critical knowledge gap, we investigated wether LECs interact with LAM-cells to augment their metastatic behaviour of LAM-cells. We performed in situ spatialomics and identified a core of transcriptomically related cells within the LAM nodules. Pathway analysis highlights wound and pulmonary healing, VEGF signaling, extracellular matrix/actin cytoskeletal regulating and the HOTAIR regulatory pathway enriched in the LAM Core cells. We developed an organoid co-culture model combining primary LAM-cells with LECs and applied this to evaluate invasion, migration, and the impact of Sorafenib, a multi-kinase inhibitor. LAM-LEC organoids had significantly higher extracellular matrix invasion, decreased solidity and a greater perimeter, reflecting increased invasion compared to non-LAM control smooth muscle cells. Sorafenib significantly inhibited this invasion in both LAM spheroids and LAM-LEC organoids compared to their respective controls. We identified TGFß1ι1, a molecular adapter coordinating protein-protein interactions at the focal adhesion complex and known to regulate VEGF, TGFß and Wnt signalling, as a Sorafenib-regulated kinase in LAM-cells. In conclusion we have developed a novel 3D co-culture LAM model and have demonstrated the effectiveness of Sorafenib to inhibit LAM-cell invasion, identifying new avenues for therapeutic intervention.

Neutrophilic inflammation promotes SARS-CoV-2 infectivity and augments the inflammatory responses in airway epithelial cells.

Introduction: In response to viral infection, neutrophils release inflammatory mediators as part of the innate immune response, contributing to pathogen clearance through virus internalization and killing. Pre- existing co-morbidities correlating to incidence to severe COVID-19 are associated with chronic airway neutrophilia. Furthermore, examination of COVID-19 explanted lung tissue revealed a series of epithelial pathologies associated with the infiltration and activation of neutrophils, indicating neutrophil activity in response to SARS-CoV-2 infection. Methods: To determine the impact of neutrophil-epithelial interactions on the infectivity and inflammatory responses to SARS-CoV-2 infection, we developed a co-culture model of airway neutrophilia. This model was infected with live SARS-CoV-2 virus the epithelial response to infection was evaluated. Results: SARS-CoV-2 infection of airway epithelium alone does not result in a notable pro-inflammatory response from the epithelium. The addition of neutrophils induces the release of proinflammatory cytokines and stimulates a significantly augmented proinflammatory response subsequent SARS-CoV-2 infection. The resulting inflammatory responses are polarized with differential release from the apical and basolateral side of the epithelium. Additionally, the integrity of the \epithelial barrier is impaired with notable epithelial damage and infection of basal stem cells. Conclusions: This study reveals a key role for neutrophil-epithelial interactions in determining inflammation and infectivity.

Identifying Root Causes: Evaluation of a Program to Engage Youth in a Social Justice Approach to Tobacco Control.

Movements designed to engage youth in tobacco control have been an important part of tobacco prevention for decades. Today, young people are increasingly diverse, and their primary issues of concern are gun control, racism, mental health, and climate change. To engage today's young people, tobacco control programs need to draw connections between youth's identities, top issues, and tobacco. UpRISE is a social justice youth tobacco control movement that engages diverse youth in identifying the root causes of youth nicotine use. In 2018-2019, 21 youth-serving organizations and schools hosted youth coalitions. Coalitions engaged in a six-session workbook called "Getting to the root cause," and adults were provided training and reflective supervision. Pre/post surveys with youth participants (n = 180) and end-of-year interviews with adult facilitators (n = 22) were used to assess outcomes. The primary outcomes were supportive adult relationships, youth voice in decision-making, anti-tobacco industry attitudes and beliefs, psychological empowerment, critical consciousness, and global belief in a just world. Quantitative measures of supportive adult relationships, youth voice in decision-making, psychological empowerment, and anti-tobacco industry attitudes and beliefs all increased significantly over time (p < .0001, p < .0001, p < .0001, p = .0034, respectively). Critical consciousness and global belief in a just world did not change significantly. During interviews, adults reported learning how: to engage in youth-adult partnerships, the tobacco industry abused its power, to engage in critical reflection about power. Adults also felt empowered. UpRISE may be a promising approach to increase racially diverse youth's engagement in social justice-oriented tobacco control efforts that advance equity.

Quantitative Analysis and Optimization of Site-Specific Protein Bioconjugation in Mammalian Cells.

Despite a range of covalent protein modifications, few techniques exist for quantification of protein bioconjugation in cells. Here, we describe a novel method for quantifying in cellulo protein bioconjugation through covalent bond formation with HaloTag. This approach utilizes unnatural amino acid (UAA) mutagenesis to selectively install a small and bioorthogonally reactive handle onto the surface of a protein. We utilized the fast kinetics and high selectivity of inverse electron-demand Diels-Alder cycloadditions to evaluate reactions of tetrazine phenylalanine (TetF) with strained trans-cyclooctene-chloroalkane (sTCO-CA) and trans-cyclooctene lysine (TCOK) with tetrazine-chloroalkane (Tet-CA). Following bioconjugation, the chloroalkane ligand is exposed for labeling by the HaloTag enzyme, allowing for straightforward quantification of bioconjugation via simple western blot analysis. We demonstrate the versatility of this tool for quickly and accurately determining the bioconjugation efficiency of different UAA/chloroalkane pairs and for different sites on different proteins of interest, including EGFP and the estrogen-related receptor ERRα.

Stem cells, cell therapies, and bioengineering in lung biology and disease 2021.

The 9th biennial conference titled "Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases" was hosted virtually, due to the ongoing COVID-19 pandemic, in collaboration with the University of Vermont Larner College of Medicine, the National Heart, Lung, and Blood Institute, the Alpha-1 Foundation, the Cystic Fibrosis Foundation, and the International Society for Cell & Gene Therapy. The event was held from July 12th through 15th, 2021 with a pre-conference workshop held on July 9th. As in previous years, the objectives remained to review and discuss the status of active research areas involving stem cells (SCs), cellular therapeutics, and bioengineering as they relate to the human lung. Topics included 1) technological advancements in the in situ analysis of lung tissues, 2) new insights into stem cell signaling and plasticity in lung remodeling and regeneration, 3) the impact of extracellular matrix in stem cell regulation and airway engineering in lung regeneration, 4) differentiating and delivering stem cell therapeutics to the lung, 5) regeneration in response to viral infection, and 6) ethical development of cell-based treatments for lung diseases. This selection of topics represents some of the most dynamic and current research areas in lung biology. The virtual workshop included active discussion on state-of-the-art methods relating to the core features of the 2021 conference, including in situ proteomics, lung-on-chip, induced pluripotent stem cell (iPSC)-airway differentiation, and light sheet microscopy. The conference concluded with an open discussion to suggest funding priorities and recommendations for future research directions in basic and translational lung biology.

Cell-free DNA Predicts Prolonged Response to Multi-agent Chemotherapy in Pancreatic Ductal Adenocarcinoma.

The treatment of metastatic pancreatic ductal adenocarcinoma (PDAC) is frequently characterized by significant toxicity and rapid development of resistance to current approved therapies. More reliable biomarkers of response are needed to guide clinical decision making. We evaluated cell-free DNA (cfDNA) using a tumor-agnostic platform and traditional biomarkers (CEA and CA19-9) levels in 12 patients treated at Johns Hopkins University on NCT02324543 "Study of Gemcitabine/Nab-Paclitaxel/Xeloda (GAX) in Combination With Cisplatin and Irinotecan in Subjects With Metastatic Pancreatic Cancer." The pretreatment values, levels after 2 months of treatment, and change in biomarker levels with treatment were compared with clinical outcomes to determine their predictive value. The variant allele frequency (VAF) of KRAS and TP53 mutations in cfDNA after 2 months of treatment was predictive of progression-free survival (PFS) and overall survival (OS). In particular, patients with a lower-than-average KRAS VAF after 2 months of treatment had a substantially longer PFS than patients with higher posttreatment KRAS VAF (20.96 vs. 4.39 months). Changes in CEA and CA19-9 after 2 months of treatment were also good predictors of PFS. Comparison via concordance index demonstrated KRAS or TP53 VAF after 2 months of treatment to be better predictors of PFS and OS than CA19-9 or CEA. This pilot study requires validation but suggests cfDNA measurement is a useful adjunct to traditional protein biomarkers and imaging evaluation and could distinguish between patients who are likely to achieve prolonged responses versus those that will have early progression and may benefit from a change in treatment approach. Significance: We report on the association of cfDNA with response durability for patients undergoing treatment with a novel metronomic chemotherapy regimen (gemcitabine, nab-paclitaxel, capecitabine, cisplatin, irinotecan; GAX-CI) for metastatic PDAC. This investigation offers encouraging evidence that cfDNA may prove to be a valuable diagnostic tool to guide clinical management.

Targeted Protein Degradation through Fast Optogenetic Activation and Its Application to the Control of Cell Signaling.

Development of methodologies for optically triggered protein degradation enables the study of dynamic protein functions, such as those involved in cell signaling, that are difficult to be probed with traditional genetic techniques. Here, we describe the design and implementation of a novel light-controlled peptide degron conferring N-end pathway degradation to its protein target. The degron comprises a photocaged N-terminal amino acid and a lysine-rich, 13-residue linker. By caging the N-terminal residue, we were able to optically control N-degron recognition by an E3 ligase, consequently controlling ubiquitination and proteasomal degradation of the target protein. We demonstrate broad applicability by applying this approach to a diverse set of target proteins, including EGFP, firefly luciferase, the kinase MEK1, and the phosphatase DUSP6 (also known as MKP3). The caged degron can be used with minimal protein engineering and provides virtually complete, light-triggered protein degradation on a second to minute time scale.

Transcriptional analysis of cystic fibrosis airways at single-cell resolution reveals altered epithelial cell states and composition.

Cystic fibrosis (CF) is a lethal autosomal recessive disorder that afflicts more than 70,000 people. People with CF experience multi-organ dysfunction resulting from aberrant electrolyte transport across polarized epithelia due to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF-related lung disease is by far the most important determinant of morbidity and mortality. Here we report results from a multi-institute consortium in which single-cell transcriptomics were applied to define disease-related changes by comparing the proximal airway of CF donors (n = 19) undergoing transplantation for end-stage lung disease with that of previously healthy lung donors (n = 19). Disease-dependent differences observed include an overabundance of epithelial cells transitioning to specialized ciliated and secretory cell subsets coupled with an unexpected decrease in cycling basal cells. Our study yields a molecular atlas of the proximal airway epithelium that will provide insights for the development of new targeted therapies for CF airway disease.

Engineering Tissue-Informed Biomaterials to Advance Pulmonary Regenerative Medicine.

Biomaterials intentionally designed to support the expansion, differentiation, and three-dimensional (3D) culture of induced-pluripotent stem cells (iPSCs) may pave the way to cell-based therapies for chronic respiratory diseases. These conditions are endured by millions of people worldwide and represent a significant cause of morbidity and mortality. Currently, there are no effective treatments for the majority of advanced lung diseases and lung transplantation remains the only hope for many chronically ill patients. Key opinion leaders speculate that the novel coronavirus, COVID-19, may lead to long-term lung damage, further exacerbating the need for regenerative therapies. New strategies for regenerative cell-based therapies harness the differentiation capability of human iPSCs for studying pulmonary disease pathogenesis and treatment. Excitingly, biomaterials are a cell culture platform that can be precisely designed to direct stem cell differentiation. Here, we present a closer look at the state-of-the-art of iPSC differentiation for pulmonary engineering, offer evidence supporting the power of biomaterials to improve stem cell differentiation, and discuss our perspective on the potential for tissue-informed biomaterials to transform pulmonary regenerative medicine.

Challenges of the current precision medicine approach for pancreatic cancer: A single institution experience between 2013 and 2017.

Recent research on genomic profiling of pancreatic ductal adenocarcinoma (PDAC) has identified many potentially actionable alterations. However, the feasibility of using genomic profiling to guide routine clinical decision making for PDAC patients remains unclear. We retrospectively reviewed PDAC patients between October 2013 and December 2017, who underwent treatment at the Johns Hopkins Hospital and had clinical tumor next-generation sequencing (NGS) through commercial resources. Ninety-two patients with 93 tumors tested were included. Forty-eight (52%) patients had potentially curative surgeries. The median time from the tissue available to the NGS testing ordered was 229 days (interquartile range 62-415). A total of three (3%) patients had matched targeted therapies based on genomic profiling results. Genomic profiling guided personalized treatment for PDAC patients is feasible, but the percentage of patients who receive targeted therapy is low. The main challenges are ordering NGS testing early in the clinical course of the disease and the limited evidence of using a targeted approach in these patients. A real-time department level genomic testing ordering system in combination with an evidence-based flagging system for potentially actionable alterations could help address these shortcomings.

Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Disease 2019.

A workshop entitled "Stem Cells, Cell Therapies and Bioengineering in Lung Biology and Diseases" was hosted by the University of Vermont Larner College of Medicine in collaboration with the National Heart, Lung and Blood Institute, the Alpha-1 Foundation, the Cystic Fibrosis Foundation, the International Society for Cell and Gene Therapy and the Pulmonary Fibrosis Foundation. The event was held from July 15 to 18, 2019 at the University of Vermont, Burlington, Vermont. The objectives of the conference were to review and discuss the current status of the following active areas of research: 1) technological advancements in the analysis and visualisation of lung stem and progenitor cells; 2) evaluation of lung stem and progenitor cells in the context of their interactions with the niche; 3) progress toward the application and delivery of stem and progenitor cells for the treatment of lung diseases such as cystic fibrosis; 4) progress in induced pluripotent stem cell models and application for disease modelling; and 5) the emerging roles of cell therapy and extracellular vesicles in immunomodulation of the lung. This selection of topics represents some of the most dynamic research areas in which incredible progress continues to be made. The workshop also included active discussion on the regulation and commercialisation of regenerative medicine products and concluded with an open discussion to set priorities and recommendations for future research directions in basic and translation lung biology.

Correcting CFTR: New Gene Editing Strategies for Rescuing CFTR Function Ex Vivo.

Gene correction presents one of few options for a cure for all patients with cystic fibrosis. This commentary discusses new applications of CRISPR-based gene editing technology with increased efficiency and specificity to correct the cystic fibrosis transmembrane regulator (CFTR) function in patient-specific primary epithelial cells.

Derivation of induced pluripotent stem cells from ferret somatic cells.

Ferrets are an attractive mammalian model for several diseases, especially those affecting the lungs, liver, brain, and kidneys. Many chronic human diseases have been difficult to model in rodents due to differences in size and cellular anatomy. This is particularly the case for the lung, where ferrets provide an attractive mammalian model of both acute and chronic lung diseases, such as influenza, cystic fibrosis, A1A emphysema, and obliterative bronchiolitis, closely recapitulating disease pathogenesis, as it occurs in humans. As such, ferrets have the potential to be a valuable preclinical model for the evaluation of cell-based therapies for lung regeneration and, likely, for other tissues. Induced pluripotent stem cells (iPSCs) provide a great option for provision of enough autologous cells to make patient-specific cell therapies a reality. Unfortunately, they have not been successfully created from ferrets. In this study, we demonstrate the generation of ferret iPSCs that reflect the primed pluripotent state of human iPSCs. Ferret fetal fibroblasts were reprogrammed and acquired core features of pluripotency, having the capacity for self-renewal, multilineage differentiation, and a high-level expression of the core pluripotency genes and pathways at both the transcriptional and protein level. In conclusion, we have generated ferret pluripotent stem cells that provide an opportunity for advancing our capacity to evaluate autologous cell engraftment in ferrets.

Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases 2017. An Official American Thoracic Society Workshop Report.

The University of Vermont Larner College of Medicine, in collaboration with the National Heart, Lung, and Blood Institute (NHLBI), the Alpha-1 Foundation, the American Thoracic Society, the Cystic Fibrosis Foundation, the European Respiratory Society, the International Society for Cell & Gene Therapy, and the Pulmonary Fibrosis Foundation, convened a workshop titled "Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases" from July 24 through 27, 2017, at the University of Vermont, Burlington, Vermont. The conference objectives were to review and discuss current understanding of the following topics: 1) stem and progenitor cell biology and the role that they play in endogenous repair or as cell therapies after lung injury, 2) the emerging role of extracellular vesicles as potential therapies, 3) ex vivo bioengineering of lung and airway tissue, and 4) progress in induced pluripotent stem cell protocols for deriving lung cell types and applications in disease modeling. All of these topics are research areas in which significant and exciting progress has been made over the past few years. In addition, issues surrounding the ethics and regulation of cell therapies worldwide were discussed, with a special emphasis on combating the growing problem of unproven cell interventions being administered to patients with lung diseases. Finally, future research directions were discussed, and opportunities for both basic and translational research were identified.

Lack of thromboprophylaxis across the care continuum in US medical patients.

Venous thromboembolism (VTE) prophylaxis is suboptimal, with many at-risk medical patients not receiving anticoagulants in hospital. Among those who receive anticoagulants in the hospital, thromboprophylaxis is frequently stopped at discharge despite persistent risk. Few studies have investigated prophylaxis use across the continuum of care. We analyzed anticoagulant use in medical patients in hospital and after discharge. Patient records (January 2005-December 2007) from medical patients with cancer, heart failure, severe lung disease, or infectious disease who were deemed at risk for VTE by the 2008 American College of Chest Physicians guidelines were included. Records were queried for inpatient and outpatient anticoagulant use by cross-matching data from the Premier Perspective discharge database with the i3/Ingenix LabRx outpatient and inpatient database. Of the 9675 medical patients identified, only 36.1% received inpatient anticoagulation (24.9% cancer patients, 30.1% infectious disease patients, 42.5% severe lung disease patients, and 56.3% heart failure patients). Of those who received in-hospital anticoagulants, most received enoxaparin (58.6%) followed by unfractionated heparin and other prophylactic agents. Only 1.8% of medical patients were prescribed anticoagulants within 30 days after discharge, ranging from 1.1% of patients with infectious disease to 4.8% of patients with heart failure. The majority of patients discharged who received outpatient anticoagulation filled prescriptions for warfarin, followed by enoxaparin plus warfarin. This real-world study demonstrates that only one-third of at-risk medical patients receive anticoagulants in hospital, with < 2% continuing to receive prophylaxis after discharge. Therefore, there is a need to improve the provision of thromboprophylaxis in the continuum of care for acutely ill medical patients.

Need to improve thromboprophylaxis across the continuum of care for surgical patients.

INTRODUCTION: Prophylaxis for venous thromboembolism (VTE) is underused following major surgery and frequently stopped at hospital discharge despite short stays and high VTE risk for several weeks postsurgery. We evaluated inpatient and postdischarge prophylaxis in patients who underwent major abdominal or orthopedic surgery. METHODS: Patient records were assessed for anticoagulant use by cross-matching data from the Premier's Perspective discharge database with the i3/Ingenix LabRx outpatient and inpatient database from January 2005 to December 2007. Abdominal or orthopedic surgery patients at risk of VTE according to the 2004 American College of Chest Physicians guidelines and with no contraindications to anticoagulation were included. RESULTS: A total of 14,009 eligible surgical discharges were analyzed. Only 27.9% of the 10,698 abdominal surgery patients received anticoagulation in hospital. Most inpatients received unfractionated heparin (12.3% of the total abdominal surgery population) or enoxaparin (11.8%). Of the 3311 orthopedic surgery patients, 91.1% received in-hospital anticoagulation. Similar proportions of patients received enoxaparin (32.1%), warfarin (31.1%), or other agents (28.0%). Only 1.2% of abdominal surgery patients had an anticoagulant prescription filled 30 days postdischarge. Although orthopedic surgery outpatients had higher anticoagulation rates, only 54.4% had filled a prescription 30 days postdischarge with 31.1% receiving warfarin, 18.5% receiving enoxaparin, and 4.8% receiving other anticoagulants. The higher prophylaxis rate in orthopedic patients may reflect the high VTE risk in orthopedic surgery patients and increased awareness among orthopedic surgeons. CONCLUSION: This real-world study highlights the underuse of thromboprophylaxis in hospitalized surgical patients, especially following abdominal surgery. Furthermore, a considerable proportion of these patients do not receive postdischarge anticoagulation despite guideline recommendations. Further efforts are needed to improve anticoagulant use, particularly in the outpatient setting.