Successful Extension of Vascularized Composite Allograft Perfusion Cold Storage to 24 h in a Rat Hindlimb Transplant Model.

Background: Vascularized composite allograft transplantation is a treatment option for complex tissue injuries; however, ischemia reperfusion injury and high acute rejection rates remain a challenge. Hypothermic machine perfusion using acellular storage perfusate is a potential solution. This study evaluated the University of Wisconsin Kidney Preservation Solution-1 (KPS-1) compared with normal saline (NS) for preservation of donor rat hindlimbs subjected to 24 h of ex vivo perfusion cold storage. Methods: Hindlimbs were subjected to 24-h perfusion cold storage with heparinized KPS-1 (n = 6) or heparinized NS (n = 6). Flow, resistance, and pH were measured continuously. At the end of the 24-h period, tissue was collected for histological analysis of edema and apoptosis. Results: KPS-1 perfused limbs showed significantly less edema than the NS group, as evidenced by lower limb weight gain (P < 0.001) and less interfascicular space (P < 0.001). KPS-perfused muscle had significantly less cell death than NS-perfused muscle based on terminal deoxynucleotidyl transferase dUTP nick-end labeling (P < 0.001) and cleaved caspase-3 staining (P = 0.045). During hypothermic machine perfusion, a significant decrease in pH over time was detected in both groups, with a significantly greater decline in pH in the KPS-1 group than in the NS group. There were no significant differences overall and over time in flow rate or vascular resistance between the KPS and NS groups. Conclusions: Perfusion with KPS-1 can successfully extend vascularized composite allograft perfusion cold storage for 24 h in a rat hindlimb model without significant edema or cell death.

Factors Associated with Inhaled Bronchodilator and Oral Corticosteroid Use in Young Children with First Lower Respiratory Tract Infection.

OBJECTIVES: To examine factors associated with claims for and potential overuse of inhaled bronchodilators (IBs) and oral corticosteroids (OCSs) for children <2 years old at first lower respiratory tract infections (LRTIs). STUDY DESIGN: Retrospective cohort study using Colorado All Payer Claims data from 2009 through 2019. Children with asthma were excluded. Primary outcomes were 1) IB and 2) OCS claims within 7 days of index LRTI. Primary predictors were previous IB or OCS claims for each outcome respectively. Covariates included demographics, atopy, family history of asthma, complex chronic conditions, prior inhaled corticosteroid claim, and location of index LRTI. Separate multivariable logistic regression models were used for each outcome. RESULTS: Of 10 194 eligible children, 1468 (14.4%) had an IB and 741 (7.3%) an OCS claim at or within 7 days of index LRTI. Index LRTIs were most often at outpatient visits (64%). Adjusting for covariates, prior IB prescription was associated with the IB outcome (aOR 1.9; 95% CI 1.3, 2.8), and prior OCS prescription was associated with the OCS outcome (AOR 2.2; 95% CI 1.7, 2.9). Other variables associated with either outcome included age, sex, insurance, location, and atopy. Prior inhaled corticosteroid claim, asthma family history, and complex chronic conditions were not associated with either outcome. CONCLUSIONS: This study identifies factors that might serve as opportunities for de-implementation strategies for IB and OCS overuse in young children with LRTI.

Intravenous BCG vaccination reduces SARS-CoV-2 severity and promotes extensive reprogramming of lung immune cells.

Bacillus Calmette-Guérin (BCG) confers heterologous immune protection against viral infections and has been proposed as vaccine against SARS-CoV-2 (SCV2). Here, we tested intravenous BCG vaccination against COVID-19 using the golden Syrian hamster model. BCG vaccination conferred a modest reduction on lung SCV2 viral load, bronchopneumonia scores, and weight loss, accompanied by a reversal of SCV2-mediated T cell lymphopenia, and reduced lung granulocytes. BCG uniquely recruited immunoglobulin-producing plasma cells to the lung suggesting accelerated local antibody production. BCG vaccination also recruited elevated levels of Th1, Th17, Treg, CTLs, and Tmem cells, with a transcriptional shift away from exhaustion markers and toward antigen presentation and repair. Similarly, BCG enhanced recruitment of alveolar macrophages and reduced key interstitial macrophage subsets, that show reduced IFN-associated gene expression. Our observations indicate that BCG vaccination protects against SCV2 immunopathology by promoting early lung immunoglobulin production and immunotolerizing transcriptional patterns among key myeloid and lymphoid populations.

A Shared Pathogenic Mechanism for Valproic Acid and SHROOM3 Knockout in a Brain Organoid Model of Neural Tube Defects.

Neural tube defects (NTDs), including anencephaly and spina bifida, are common major malformations of fetal development resulting from incomplete closure of the neural tube. These conditions lead to either universal death (anencephaly) or severe lifelong complications (spina bifida). Despite hundreds of genetic mouse models of neural tube defect phenotypes, the genetics of human NTDs are poorly understood. Furthermore, pharmaceuticals, such as antiseizure medications, have been found clinically to increase the risk of NTDs when administered during pregnancy. Therefore, a model that recapitulates human neurodevelopment would be of immense benefit to understand the genetics underlying NTDs and identify teratogenic mechanisms. Using our self-organizing single rosette cortical organoid (SOSR-COs) system, we have developed a high-throughput image analysis pipeline for evaluating the SOSR-CO structure for NTD-like phenotypes. Similar to small molecule inhibition of apical constriction, the antiseizure medication valproic acid (VPA), a known cause of NTDs, increases the apical lumen size and apical cell surface area in a dose-responsive manner. GSK3ß and HDAC inhibitors caused similar lumen expansion; however, RNA sequencing suggests VPA does not inhibit GSK3ß at these concentrations. The knockout of SHROOM3, a well-known NTD-related gene, also caused expansion of the lumen, as well as reduced f-actin polarization. The increased lumen sizes were caused by reduced cell apical constriction, suggesting that impingement of this process is a shared mechanism for VPA treatment and SHROOM3-KO, two well-known causes of NTDs. Our system allows the rapid identification of NTD-like phenotypes for both compounds and genetic variants and should prove useful for understanding specific NTD mechanisms and predicting drug teratogenicity.

A Shared Pathogenic Mechanism for Valproic Acid and SHROOM3 Knockout in a Brain Organoid Model of Neural Tube Defects.

Neural tube defects (NTDs) including anencephaly and spina bifida are common major malformations of fetal development resulting from incomplete closure of the neural tube. These conditions lead to either universal death (anencephaly) or life-long severe complications (spina bifida). Despite hundreds of genetic mouse models having neural tube defect phenotypes, the genetics of human NTDs are poorly understood. Furthermore, pharmaceuticals such as antiseizure medications have been found clinically to increase the risk of NTDs when administered during pregnancy. Therefore, a model that recapitulates human neurodevelopment would be of immense benefit to understand the genetics underlying NTDs and identify teratogenic mechanisms. Using our self-organizing single rosette spheroid (SOSRS) brain organoid system, we have developed a high-throughput image analysis pipeline for evaluating SOSRS structure for NTD-like phenotypes. Similar to small molecule inhibition of apical constriction, the antiseizure medication valproic acid (VPA), a known cause of NTDs, increases the apical lumen size and apical cell surface area in a dose-responsive manner. This expansion was mimicked by GSK3ß and HDAC inhibitors; however, RNA sequencing suggests VPA does not inhibit GSK3ß at these concentrations. Knockout of SHROOM3, a well-known NTD-related gene, also caused expansion of the lumen as well as reduced f-actin polarization. The increased lumen sizes were caused by reduced cell apical constriction suggesting that impingement of this process is a shared mechanism for VPA treatment and SHROOM3-KO, two well-known causes of NTDs. Our system allows the rapid identification of NTD-like phenotypes for both compounds and genetic variants and should prove useful for understanding specific NTD mechanisms and predicting drug teratogenicity.

Improved bladder cancer antitumor efficacy with a recombinant BCG that releases a STING agonist.

Despite the introduction of several new agents for the treatment of bladder cancer (BC), intravesical BCG remains a first line agent for the management of non-muscle invasive bladder cancer. In this study we evaluated the antitumor efficacy in animal models of BC of a recombinant BCG known as BCG-disA-OE that releases the small molecule STING agonist c-di-AMP. We found that compared to wild-type BCG (BCG-WT), in both the orthotopic, carcinogen-induced rat MNU model and the heterotopic syngeneic mouse MB-49 model BCG-disA-OE afforded improved antitumor efficacy. A mouse safety evaluation further revealed that BCG-disA-OE proliferated to lesser degree than BCG-WT in BALB/c mice and displayed reduced lethality in SCID mice. To probe the mechanisms that may underlie these effects, we found that BCG-disA-OE was more potent than BCG-WT in eliciting IFN-ß release by exposed macrophages, in reprogramming myeloid cell subsets towards an M1-like proinflammatory phenotypes, inducing epigenetic activation marks in proinflammatory cytokine promoters, and in shifting monocyte metabolomic profiles towards glycolysis. Many of the parameters elevated in cells exposed to BCG-disA-OE are associated with BCG-mediated trained innate immunity suggesting that STING agonist overexpression may enhance trained immunity. These results indicate that modifying BCG to release high levels of proinflammatory PAMP molecules such as the STING agonist c-di-AMP can enhance antitumor efficacy in bladder cancer.

Immediate extubation following pediatric liver transplantation.

BACKGROUND: Immediate extubation (IE) following pediatric liver transplantation is being increasingly performed. The aim of this study was to characterize the rate of IE at our institution and identify recipient factors predictive of IE. METHODS: All pediatric liver transplants performed at our institution between January 1, 2015 and December 31, 2020 were reviewed. Retransplants and multi-organ transplants were excluded. IE was defined as extubation in the operating room following transplant. Backward stepwise logistic regression at a p-value threshold of .05 was performed to identify variables associated with IE. RESULTS: IE was achieved in 58 (72%) of the 81 pediatric liver transplants. The IE cohort had significantly shorter ICU length of stay and overall hospital length of stay, though IE was not an independent predictor of posttransplant length of stay. Age <2 years, preoperative mechanical ventilation, and total intraoperative epinephrine and dopamine infusion requirements were significant, independent risk factors against IE. This multivariable model was highly predictive of IE (area under the curve = 0.89). CONCLUSIONS: We describe the highest rate of IE postpediatric liver transplantation that has been reported to date and identified significant risk factors against successful IE.

Dynamic single-cell RNA sequencing reveals BCG vaccination curtails SARS-CoV-2 induced disease severity and lung inflammation.

COVID-19 continues to exact a toll on human health despite the availability of several vaccines. Bacillus Calmette Guérin (BCG) has been shown to confer heterologous immune protection against viral infections including COVID-19 and has been proposed as vaccine against SARS-CoV-2 (SCV2). Here we tested intravenous BCG vaccination against COVID-19 using the golden Syrian hamster model together with immune profiling and single cell RNA sequencing (scRNAseq). We observed that BCG reduced both lung SCV2 viral load and bronchopneumonia. This was accompanied by an increase in lung alveolar macrophages, a reversal of SCV2-mediated T cell lymphopenia, and reduced lung granulocytes. Single cell transcriptome profiling showed that BCG uniquely recruits immunoglobulin-producing plasma cells to the lung suggesting accelerated antibody production. BCG vaccination also recruited elevated levels of Th1, Th17, Treg, CTLs, and Tmem cells, and differentially expressed gene (DEG) analysis showed a transcriptional shift away from exhaustion markers and towards antigen presentation and repair. Similarly, BCG enhanced lung recruitment of alveolar macrophages and reduced key interstitial macrophage subsets, with both cell-types also showing reduced IFN-associated gene expression. Our observations indicate that BCG vaccination protects against SCV2 immunopathology by promoting early lung immunoglobulin production and immunotolerizing transcriptional patterns among key myeloid and lymphoid populations.

Re-engineered BCG overexpressing cyclic di-AMP augments trained immunity and exhibits improved efficacy against bladder cancer.

In addition to its role as a TB vaccine, BCG has been shown to elicit heterologous protection against many other pathogens including viruses through a process termed trained immunity. Despite its potential as a broadly protective vaccine, little has been done to determine if BCG-mediated trained immunity levels can be optimized. Here we re-engineer BCG to express high levels of c-di-AMP, a PAMP recognized by stimulator of interferon genes (STING). We find that BCG overexpressing c-di-AMP elicits more potent signatures of trained immunity including higher pro-inflammatory cytokine responses, greater myeloid cell reprogramming toward inflammatory and activated states, and enhances epigenetic and metabolomic changes. In a model of bladder cancer, we also show that re-engineered BCG induces trained immunity and improved functionality. These results indicate that trained immunity levels and antitumor efficacy may be increased by modifying BCG to express higher levels of key PAMP molecules.

Extracorporeal membrane oxygenation as rescue therapy in a pediatric liver transplant recipient with very severe hepatopulmonary syndrome.

BACKGROUND: In children with cirrhosis, the prevalence of HPS ranges from 3% to 20%, resulting in impaired gas exchange due to alterations in pulmonary microvasculature. LT is the gold-standard cure for cirrhosis complicated by HPS and should ideally be performed prior to the development of severe HPS due to increased risk for post-transplant hypoxia, right heart failure, and outflow obstruction. METHODS: We present a case of a 13-year-old man, who underwent pediatric LT for severe HPS complicated by postoperative respiratory collapse, requiring a 92-day course of veno-venous ECMO. RESULTS: Post-transplant, despite BiPAP, inhaled nitric oxide and isoproterenol infusion, he remained hypoxic postoperatively and acutely decompensated on postoperative day 25, requiring veno-venous ECMO. After 84 days on ECMO, a persistent large splenorenal shunt was identified that was embolized by interventional radiology, and 8 days after shunt embolization and ASD closure, he was successfully weaned off ECMO. CONCLUSIONS: This case describes the longest known duration of ECMO in a pediatric LT recipient and a unique improvement in hypoxemia following a portosystemic shunt closure. ECMO presents a heroic rescue measure for pediatric LT recipients with HPS that develops acute respiratory failure postoperatively refractory to alternative measures.

Automated, multiparametric monitoring of respiratory biomarkers and vital signs in clinical and home settings for COVID-19 patients.

Capabilities in continuous monitoring of key physiological parameters of disease have never been more important than in the context of the global COVID-19 pandemic. Soft, skin-mounted electronics that incorporate high-bandwidth, miniaturized motion sensors enable digital, wireless measurements of mechanoacoustic (MA) signatures of both core vital signs (heart rate, respiratory rate, and temperature) and underexplored biomarkers (coughing count) with high fidelity and immunity to ambient noises. This paper summarizes an effort that integrates such MA sensors with a cloud data infrastructure and a set of analytics approaches based on digital filtering and convolutional neural networks for monitoring of COVID-19 infections in sick and healthy individuals in the hospital and the home. Unique features are in quantitative measurements of coughing and other vocal events, as indicators of both disease and infectiousness. Systematic imaging studies demonstrate correlations between the time and intensity of coughing, speaking, and laughing and the total droplet production, as an approximate indicator of the probability for disease spread. The sensors, deployed on COVID-19 patients along with healthy controls in both inpatient and home settings, record coughing frequency and intensity continuously, along with a collection of other biometrics. The results indicate a decaying trend of coughing frequency and intensity through the course of disease recovery, but with wide variations across patient populations. The methodology creates opportunities to study patterns in biometrics across individuals and among different demographic groups.

Immunotherapy in Advanced Lung Cancer.

Historically, platinum-based chemotherapy was the standard of care for metastatic lung cancer. However, since the success of immune checkpoint inhibitors (ICIs) in melanoma, PD-1/PD-L1 and CTLA-4 immune checkpoint pathways have been established as effective therapies to manage advanced non-small cell lung cancer (NSCLC) and extensive-stage (ES) small cell lung cancer (SCLC). Multiple large-scale randomized clinical trials have analyzed the effects of ICIs in NSCLC, and results of these trials have since translated to the approval of single-agent PD-1/PD-L1 inhibitors, and the combination of PD-1 inhibitors with platinum-based chemotherapy has become the new standard of care for patients with advanced NSCLC. Furthermore, in ES SCLC, in which chemotherapy or chemoradiation has been the standard of care for decades, 2 anti-PD-1/PD-L1 agents have been approved for use in the frontline setting for ES SCLC, in combination with chemotherapy. Despite progressive integration of immunotherapy into treatment regimens, there remains a need for reliable biomarkers to precisely determine therapy candidates.

Immunotherapy in Advanced Non-Small Cell Lung Cancer.

Traditionally, lung cancer has been treated as an immune-resistant disease with platinum-based chemotherapy serving as the first-line treatment for metastatic disease. The efficacy of immunotherapy has been established for patients with advanced lung cancer in clinical trials, and it has since become the standard of care for patients without targetable mutations, with or without chemotherapy. Previously, lung cancer patients experienced limited responses to immune-based therapy. As clinical trials continued to explore immunotherapy options with checkpoint inhibitors, results showed that immune therapies can create durable responses with manageable toxicities. Patients with advanced non-small cell lung cancer (NSCLC) can experience improved survival when administered immunotherapy over chemotherapy. The first successful immunotherapy treatments developed exploit programmed death 1/programmed death ligand 1 (PD-1/PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), immune checkpoint pathways. Combination therapies of PD-1/PD-L1 inhibitors and chemotherapy or PD-1/PD-L1 and CTLA-4 checkpoint pathway inhibitors have also demonstrated improved outcomes for patients with NSCLC. Combination therapy with PD-1 or PD-L1 therapy and chemotherapy has shown benefit for small cell lung cancer patients as well. As immunotherapy changes the treatment paradigm of lung cancer, researchers continue to investigate different combinations, timing, duration, and biomarkers to better understand and improve the efficacy of immune-based therapy for patients with lung cancer.

Vitreous Hemorrhage in the Setting of a Vascular Loop.

Although uncommon, vascular loops should be kept in the differential diagnosis of vitreous hemorrhage, and patients should seek care if experiencing new floaters or visual loss.

Peripheral Exudative Hemorrhagic Chorioretinopathy in Patients With Nonexudative Age-Related Macular Degeneration.

Although uncommon, peripheral exudative hemorrhagic chorioretinopathy should be considered when evaluating a peripheral dark elevated lesion to prevent unnecessary treatments in patients.

Dimer conformation of soluble PECAM-1, an endothelial marker.

Platelet endothelial cell adhesion molecule 1 (PECAM-1) is a cell surface receptor widely distributed on endothelium and hematopoietic-derived cells, and maintain the integrity of the blood vessels. PECAM-1 is widely recognized as an endothelial cell marker. The homophilic interaction through its extracellular domain of PECAM-1 (soluble PECAM-1, or sPECAM-1) is important to its functions. However, structural details for such dimerization are not fully understood. Here we report the production of recombinant sPECAM-1 in large quantity by Drosophila expression system and the small-angle X-ray diffraction (SAXS) study. The recombinant sPECAM-1 was found to form one population of dimer, but not oligomer, and was able to bind to heparin immobilized on a chip in surface plasmon resonance imaging (SPRi) binding experiments. The results of SAXS demonstrated that sPECAM-1 formed a symmetric homodimer of Ω-shape in solution, and each protomer adopted an extended conformation. The dimer is mediated through the intermolecular interactions through the first N-terminal domain (D1) of sPECAM-1. This model provides new structural information for its homophilic interaction mechanism.

Expression and crystallographic studies of the ligand-binding region of the human endocytic collagen receptor uPARAP.

Urokinase plasminogen activator receptor-associated protein (uPARAP) is an endocytic receptor that internalizes collagen for lysosomal degradation and plays an important role in matrix remodelling. Previous recombinant protein production of uPARAP in Pichia pastoris generated protein with highly heterogeneous glycans that was prone to proteolytic degradation, resulting in highly twinned crystals. In this study, the uPARAP ligand-binding region was expressed in stably transfected Drosophila S2 insect cells. The recombinant protein was homogeneous after purification by metal-affinity and anion-exchange chromatography. Crystals were obtained at two different pH values (5.3 and 7.4) and diffracted to 2.44 and 3.13 Å resolution, respectively. A model of the ligand-binding region of uPARAP was obtained by molecular replacement combined with autobuilding. As the first multidomain crystal structure of the mannose receptor family, structural characterization of the uPARAP ligand-binding region will provide insight into the pH-induced conformational rearrangements of the mannose receptor family.