Hemoglobin scavenger receptor CD163 as a potential biomarker of hemolysis induced hepatobiliary injury in sickle cell disease.

Sickle cell disease (SCD) associated chronic hemolysis promotes oxidative stress, inflammation and thrombosis leading to organ damage, including liver damage. Hemoglobin scavenger receptor CD163 plays a protective role in SCD by scavenging both hemoglobin-haptoglobin complexes and cell free hemoglobin. A limited number of studies in the past have shown a positive correlation of CD163 expression with poor disease outcomes in patients with SCD. However, the role and regulation of CD163 in SCD related hepatobiliary injury has not been fully elucidated yet. Here, we show that chronic liver injury in SCD patients is associated with elevated levels of hepatic membrane bound CD163. Hemolysis and increase in hepatic heme, hemoglobin and iron levels elevate CD163 expression in the SCD mouse liver. Mechanistically we show that HO-1 positively regulates membrane bound CD163 expression independent of NRF2 signaling in SCD liver. We further demonstrate that of the interaction between CD163 and HO-1 is not dependent on CD163-hemoglobin binding. These findings indicate that CD163 is a potential biomarker of SCD associated hepatobiliary injury. Understanding the role of HO-1 in membrane bound CD163 regulation may help identify novel therapeutic targets for hemolysis induced chronic liver injury.

Riociguat in patients with sickle cell disease and hypertension or proteinuria (STERIO-SCD): a randomised, double-blind, placebo controlled, phase 1-2 trial.

BACKGROUND: Although nitric oxide based therapeutics have been shown in preclinical models to reduce vaso-occlusive events and improve cardiovascular function, a clinical trial of a phosphodiesterase 5 inhibitor increased rates of admission to hospital for pain. We aimed to examine if riociguat, a direct stimulator of the nitric oxide receptor soluble guanylate cyclase, causes similar increases in vaso-occlusive events. METHODS: This was a phase 1-2, randomised, double blind, placebo-controlled trial. Eligible patients were 18 years or older, had confirmed sickle cell disease documented by haemoglobin electrophoresis or HPLC fractionation (haemoglobin SS, SC, Sß-thalassemia, SD, or SO-Arab), and stage 1 hypertension or proteinuria. Participants were randomly assigned 1:1 to receive either riociguat or matching placebo via a web-based system to maintain allocation concealment. Both treatments were administered orally starting at 1·0 mg three times a day up to 2·5 mg three times a day (highest tolerated dose) for 12 weeks. Dose escalation by 0·5 mg was considered every 2 weeks if systolic blood pressure was greater than 95 mm Hg and the participant had no signs of hypotension; otherwise, the last dose was maintained. The primary outcome was the proportion of participants who had at least one adjudicated treatment-emergent serious adverse event. The analysis was performed by the intention-to-treat. This trial is registered with ClinicalTrials.gov (NCT02633397) and was completed. FINDINGS: Between April 11, 2017, and Dec 31, 2021, 165 participants were screened and consented to be enrolled into the study. Of these, 130 participants were randomly assigned to either riociguat (n=66) or placebo (n=64). The proportion of participants with at least one treatment-emergent serious adverse event was 22·7% (n=15) in the riociguat group and 31·3% (n=20) in the placebo group (difference -8·5% [90% CI -21·4 to 4·5]; p=0·19). A similar pattern emerged in other key safety outcomes, sickle cell related vaso-occlusive events (16·7 [n=11] vs 21·9% [n=14]; difference -5·2% [-17·2 to 6·5]; p=0·42), mean pain severity (3·18 vs 3·32; adjusted mean difference -0·14 [-0·70 to 0·42]; p=0·69), and pain interference (3·15 vs 3·12; 0·04 [-0·62 to 0·69]; p=0·93) at 12 weeks were similar between groups. Regarding the key clinical efficacy endpoints, participants taking riociguat had a blood pressure of -8·20 mm Hg (-10·48 to -5·91) compared with -1·24 (-3·58 to 1·10) in those taking placebo (-6·96 mm Hg (90% CI -10·22 to -3·69; p<0·001). INTERPRETATION: Riociguat was safe and had a significant haemodynamic effect on systemic blood pressure. The results of this study provide measures of effect and variability that will inform power calculations for future trials. FUNDING: Bayer Pharmaceuticals.

Warm autoimmune hemolytic anemia and hemophagocytic lymphohistiocytosis/macrophage activation syndrome occurring after COVID19 infection and administration of Casirivimab + Imdevimab (COVID19 monoclonal antibody).

Warm Autoimmune Hemolytic Anemia (WAHA) is the most common form of autoimmune hemolysis and there is a growing body of evidence of an association between SARS-CoV-2 infection, WAHA and a hyperinflammatory state, including hemophagocytic lymphohistiocytosis/macrophage activation syndrome. However, there is no literature to date of WAHA or hyperinflammatory state following administration of anti-SARS-CoV-2 monoclonal antibody treatment. This report documents a case of a patient with history of WAHA who developed brisk hemolysis and a hyperinflammatory state consistent with hemophagocytic lymphohistiocytosis/macrophage activation syndrome after COVID-19 infection and treatment with an anti-SARS-CoV-2 monoclonal antibody. He was successfully treated with multimodal treatment involving steroids, intravenous immunoglobulins, rituximab, anakinra, and vincristine with resolution of the hemolysis.

Impaired hemoglobin clearance by sinusoidal endothelium promotes vaso-occlusion and liver injury in sickle cell disease.

Sickle cell disease (SCD) is a monogenic disorder that affects 100,000 African Americans and millions of people worldwide. Intra-erythrocytic polymerization of sickle hemoglobin (HbS) promotes erythrocyte sickling, impaired rheology, ischemia and hemolysis, leading to the development of progressive liver injury in SCD. Liver resident macrophages and monocytes are known to enable the clearance of HbS, however, the role of liver sinusoidal endothelial cells (LSECs) in HbS clearance and liver injury in SCD remains unknown. Using real-time intravital (in vivo) imaging in the mice liver as well as flow cytometric analysis and confocal imaging of primary human LSECs, we show for the first time that liver injury in SCD is associated with accumulation of HbS and iron in the LSECs, leading to LSEC senescence. Hb uptake by LSECs was mediated by micropinocytosis. Hepatic monocytes were observed to attenuate LSECsenescence by accelerating HbS clearance in the liver of SCD mice, however, this protection was impaired in P-selectin-deficient SCD mice secondary to reduced monocyte recruitment in the liver. These findings are the first to suggest that LSECs contribute to HbS clearance and HbS induced LSEC-senescence promotes progressive liver injury in SCD mice. Our results provide a novel insight into the pathogenesis of hemolysis induced chronic liver injury in SCD caused by LSEC senescence. Identifying the regulators of LSEC mediated HbS clearance may lead to new therapies to prevent the progression of liver injury in SCD.

Use of Disease-Modifying Treatments in Patients With Sickle Cell Disease.

Importance: Despite hydroxyurea being an established treatment for sickle cell disease (SCD), it remains underused. The recent approval of the disease-modifying treatments (DMTs) l-glutamine, crizanlizumab, and voxelotor underscores the need to understand the uptake of DMTs in the current treatment landscape. Objective: To explore characteristics that may be associated with DMT use and to describe observed patterns of yearly DMT use from 2014 to 2021. Design, Setting, and Participants: This cross-sectional study used administrative claims data from Optum's deidentified Clinformatics Data Mart Database from January 1, 2014, to September 30, 2021, to identify adults and children with SCD. Data were analyzed from August 1, 2022, to August 28, 2023. Exposure: Use of DMTs. Main Outcomes and Measures: Patient characteristics across groups with varying patterns of DMT use and yearly patterns of prescription fills for hydroxyurea, crizanlizumab, voxelotor, and l-glutamine. Results: A total of 5022 beneficiaries with SCD (2081 [41.4%] aged 18-45 years; 2929 [58.3%] female) were included in sample A (144 [2.9%] inconsistent users, 274 [5.5%] incident users, 892 [17.8%] consistent users, and 3712 [73.9%] non-DMT users). Inconsistent users had a higher prevalence of vaso-occlusive crises (mean [SD], 3.7 [4.7]), splenic complications (6 of 144 [4.2%]), pulmonary complications (36 of 144 [25.0%]), kidney disease (21 of 144 [14.6%]), acute chest syndrome (18 of 144 [12.5%]), and health care visits (eg, mean [SD] inpatient visits, 7.0 [10.7]) compared with the other use groups. Non-DMT users had the lowest prevalence of vaso-occlusive crises (mean [SD], 0.8 [2.4]), acute chest syndrome (109 of 3712 [2.9%]), and inpatient (mean [SD], 2.0 [6.6]) and emergency department (mean [SD], 0.7 [3.1]) visits and the highest proportion of adults 65 years and older (593 of 3712 [16.0%]). In sample B (6387 beneficiaries with SCD), hydroxyurea use modestly increased from 428 of 2188 participants (19.6%) in 2014 to 701 of 2880 (24.3%) in 2021. Use of l-glutamine increased briefly but gradually decreased throughout the study period. In 2021, out of 2880 participants, 102 (3.5%) had at least 1 fill for crizanlizumab and 131 (4.6%) had at least 1 fill for voxelotor. Overall, total DMT use increased from 428 of 2188 participants (19.6%) in 2014 to 815 of 2880 patients (28.3%) in 2021. Conclusions and Relevance: In this cross-sectional analysis of adults and children with SCD, uptake of DMTs remained low from 2014 to 2021, despite the approval of newer therapies. Notable differences in patient characteristics across varied DMT exposure types necessitate further exploration into factors that facilitate DMT use and the creation of strategies to enhance DMT uptake.

Targeted imaging of very late antigen-4 for noninvasive assessment of lung inflammation-fibrosis axis.

BACKGROUND: The lack of noninvasive methods for assessment of dysregulated inflammation as a major driver of fibrosis (i.e., inflammation-fibrosis axis) has been a major challenge to precision management of fibrotic lung diseases. Here, we determined the potential of very late antigen-4 (VLA-4)-targeted positron emission tomography (PET) to detect inflammation in a mouse model of bleomycin-induced fibrotic lung injury. METHOD: Single time-point and longitudinal VLA-4-targeted PET was performed using a high-affinity peptidomimetic radiotracer, 64Cu-LLP2A, at weeks 1, 2, and 4 after bleomycin-induced (2.5 units/kg) lung injury in C57BL/6J mice. The severity of fibrosis was determined by measuring the hydroxyproline content of the lungs and expression of markers of extracellular matrix remodeling. Flow cytometry and histology was performed to determine VLA-4 expression across different leukocyte subsets and their spatial distribution. RESULTS: Lung uptake of 64Cu-LLP2A was significantly elevated throughout different stages of the progression of bleomycin-induced injury. High lung uptake of 64Cu-LLP2A at week-1 post-bleomycin was a predictor of poor survival over the 4-week follow up, supporting the prognostic potential of 64Cu-LLP2A PET during the early stage of the disease. Additionally, the progressive increase in 64Cu-LLP2A uptake from week-1 to week-4 post-bleomycin correlated with the ultimate extent of lung fibrosis and ECM remodeling. Flow cytometry revealed that LLP2A binding was restricted to leukocytes. A combination of increased expression of VLA-4 by alveolar macrophages and accumulation of VLA-4-expressing interstitial and monocyte-derived macrophages as well as dendritic cells was noted in bleomycin-injured, compared to control, lungs. Histology confirmed the increased expression of VLA-4 in bleomycin-injured lungs, particularly in inflamed and fibrotic regions. CONCLUSIONS: VLA-4-targeted PET allows for assessment of the inflammation-fibrosis axis and prediction of disease progression in a murine model. The potential of 64Cu-LLP2A PET for assessment of the inflammation-fibrosis axis in human fibrotic lung diseases needs to be further investigated.

White-matter abnormalities and cognitive dysfunction are linked to astrocyte activation in sickle mice.

White-matter injury in sickle-cell disease (SCD) includes silent cerebral infarction diagnosed by diffusion tensor imaging (DTI), a complication associated with cognitive dysfunction in children with SCD. The link between white-matter injury and cognitive dysfunction has not been fully elucidated. The goal of this study was to define whether cerebrovascular lesions and cognitive function in SCD are linked to neuroaxonal damage and astrocyte activation in humanized Townes' SCD mice homozygous for human sickle hemoglobin S (SS) and control mice homozygous for human normal hemoglobin A (AA). Mice underwent MRI with DTI and cognitive testing, and histology sections from their brains were stained to assess microstructural tissue damage, neuroaxonal damage, and astrocyte activation. Fractional anisotropy, showing microstructural cerebrovascular abnormalities identified by DTI in the white matter, was significantly associated with neuronal demyelination in the SS mouse brain. SS mice had reduced learning and memory function with a significantly lower discrimination index compared with AA control mice in the novel object recognition tests. Neuroaxonal damage in the SS mice was synchronously correlated with impaired neurocognitive function and activation of astrocytes. The interplay between astrocyte function and neurons may modulate cognitive performance in SCD.

Insulin-like Growth Factor-1 Prevents Hypoxia/Reoxygenation-Induced White Matter Injury in Sickle Cell Mice.

Occlusion of cerebral blood vessels causes acute cerebral hypoxia-an important trigger of ischemic white matter injury and stroke in sickle cell disease (SCD). While chronic hypoxia triggers compensatory neuroprotection via insulin-like growth factor-1 (IGF-1) and hypoxia inducible factor-1α (HIF-1α), severe bouts of acute hypoxia and subsequent restoration of blood flow (hypoxia/reoxygenation, H/R) overwhelm compensatory mechanisms and cause neuroaxonal damage-identified as white matter lesions-in the brain. The neuroprotective role of IGF-1 in the pathogenesis of white matter injury in SCD has not been investigated; however, it is known that systemic IGF-1 is reduced in individuals with SCD. We hypothesized that IGF-1 supplementation may prevent H/R-induced white matter injury in SCD. Transgenic sickle mice homozygous for human hemoglobin S and exposed to H/R developed white matter injury identified by elevated expression of non-phosphorylated neurofilament H (SMI32) with a concomitant decrease in myelin basic protein (MBP) resulting in an increased SMI32/MBP ratio. H/R-challenge also lowered plasma and brain IGF-1 expression. Human recombinant IGF-1 prophylaxis significantly induced HIF-1α and averted H/R-induced white matter injury in the sickle mice compared to vehicle-treated mice. The expression of the IGF-1 binding proteins IGFBP-1 and IGFBP-3 was elevated in the IGF-1-treated brain tissue indicating their potential role in mediating neuroprotective HIF-1α signaling. This study provides proof-of-concept for IGF-1-mediated neuroprotection in SCD.

Diagnostic Test Accuracy of Lung Ultrasound for Acute Chest Syndrome in Sickle Cell Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Acute chest syndrome (ACS) is a leading cause of death in patients with sickle cell disease. Lung ultrasound (LUS) is emerging as a point-of-care method to diagnose ACS, allowing for more rapid diagnosis in the ED setting and sparing patients from ionizing radiation exposure. RESEARCH QUESTION: What is the diagnostic accuracy of LUS for ACS diagnosis, using the current reference standard of chest radiography? STUDY DESIGN AND METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for this systematic review and meta-analysis. Embase, MEDLINE, Web of Science, and Google Scholar were used to compile all relevant studies. Two reviewers screened the studies for inclusion in this review. Cases of discrepancy were resolved by a third reviewer. Meta-analyses were conducted using both metadta and midas STATA software packages to retrieve summary receiver operating characteristic curves, sensitivities, and specificities. Three reviewers scored the studies with QUADAS-2 for risk of bias assessment. RESULTS: From a total of 713 unique studies retrieved, six studies were included in the final quantitative synthesis. Of these, five studies were in pediatric EDs. Two studies were conference abstracts and not published manuscripts. Data were available for 625 possible ACS cases (97% of cases in patients aged ≤ 21 years) and 95 confirmed ACS diagnoses (pretest probability of 15.2%). The summary sensitivity was 0.92 (95% CI, 0.68-0.98) and the summary specificity was 0.89 (95% CI, 0.69-0.97) with an area under the curve of the summary receiver operating characteristic curve of 0.96 (95% CI, 0.94-0.97). INTERPRETATION: LUS has excellent sensitivity and very good specificity for ACS diagnosis and may serve as an initial point-of-care test to facilitate rapid treatment of ACS and spare pediatric patients from ionizing radiation; however, further research is warranted to improve the generalizability to the adult sickle cell disease population.

Astrocytic mitochondrial frataxin-A promising target for ischemic brain injury.

In the ischemic brain, hypoxia leads to mitochondrial dysfunction, insufficient energy production, and astrocyte activation. Yet, most studies investigating mitochondrial dysfunction in cerebral ischemia have focused exclusively on neurons. This review will highlight the importance of the morphological, molecular, and functional heterogeneity of astrocytes in their role in brain injuries and explore how activated astrocytes exhibit calcium imbalance, reactive oxygen species overproduction, and apoptosis. In addition, special focus will be given to the role of the mitochondrial protein frataxin in activated astrocytes during ischemia and its putative role in the pharmacological management of cerebral ischemia.

Validation of the NIH Toolbox-Cognition Battery against legacy neurocognitive measures in adults with cognitive impairments: An exploratory analysis.

OBJECTIVE: The purpose of this exploratory study was to describe associations between NIH Toolbox-Cognition Battery subtests and legacy measures of neurocognitive function in two samples with neurological conditions (stroke and sickle cell disease (SCD)). METHOD: This exploratory secondary analysis uses data from two studies that assessed cognition at one time point using the NIH Toolbox-Cognition Battery, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and subtests from the Delis-Kaplan Executive Functions System (DKEFS). People with stroke (n = 26) and SCD (n = 64) were included. Associations between the NIH Toolbox-Cognition Battery subtests and corresponding legacy measures were examined using linear correlations, Bland-Altman analysis, and Lin's Concordance Correlation Coefficient. RESULTS: Linear correlations and Lin's Concordance Correlation Coefficient were poor to strong in both samples on NIH Toolbox-CB subtests: Flanker Inhibitory Control and Attention (r = .35 to .48, Lin CCC = .27 to .37), Pattern Comparison Processing Speed (r = .40 to .65, Lin CCC = .37 to .62), Picture Sequence Memory (r = .19 to .55, Lin CCC = .18 to .48), Dimensional Change Card Sort (r = .39 to .77, Lin CCC = .38 to .63), Fluid Cognition Composite (r = .88 to .90, Lin CCC = .60 to .79), and Total Cognition Composite (r = .64 to .83, Lin CCC = .60 to .78). Bland-Altman analyses demonstrated wide limits of agreement across all subtests (-3.17 to 3.78). CONCLUSIONS: The NIH Toolbox-Cognition Battery subtests may behave similarly to legacy measures as an overall assessment of cognition across samples at risk for neurological impairment. Findings should be replicated across additional clinical samples.

Dimethyl Sulfoxide Induces Hemolysis and Pulmonary Hypertension.

Vascular and lung injury are well established complications associated with hemolytic disorders, and hemolysis associated pulmonary hypertension (PH) has emerged as the most serious complication of sickle cell disease. The causal relationship between intravascular hemolysis and the development of PH is still under investigation. Previously we have shown that repetitive administration of hemolyzed autologous blood causes PH in rats. Dimethyl sulfoxide (DMSO), a widely used solvent and anti-inflammatory agent, induces hemolysis in vivo. We hypothesized that repetitive administration of DMSO would induce PH in rats. We also examined hemolysis-induced release of adenosine deaminase (ADA) and arginase from red blood cells, which may amplify hemolysis-mediated vascular injury. Acute administration of DMSO (1.5ml/30 min into the right atrium) induced intravascular hemolysis and pulmonary vasoconstriction. DMSO-induced increase in right ventricular peak systolic pressure (RVPSP) was associated with increased release of ADA. Notably, the acute increase in RVPSP was attenuated by administration of an adenosine A2A receptor agonist or by pretreatment of animals with ADA inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA). Repetitive administration of DMSO for 10 days produced anemia, hemoglobinuria, hemoglobinemia, splenomegaly, and development of PH. Histopathological analysis revealed pulmonary vascular remodeling. The presented data describe a new model of hemolysis induced PH, suggesting that hemolysis is mechanistically related to pulmonary hypertension, and pointing to a potential pathogenic role that adenosine deaminase and accelerated adenosine metabolism may play in hemolysis associated pulmonary hypertension.

The Consortium on Newborn Screening in Africa for sickle cell disease: study rationale and methodology.

Sickle cell disease (SCD) is a common condition within sub-Saharan Africa and associated with high under-5 mortality (U5M). The American Society of Hematology instituted the Consortium on Newborn Screening in Africa (CONSA) for SCD, a 7-country network of sites to implement standardized newborn hemoglobinopathy screening and early intervention for children with SCD in sub-Saharan Africa. CONSA's overall hypothesis is that early infant SCD screening and entry into standardized, continuous care will reduce U5M compared with historical estimates in the region. Primary trial objectives are to determine the population-based birth incidence of SCD and effectiveness of early standardized care for preventing early mortality consortium-wide at each country's site(s). Secondary objectives are to establish universal screening and early interventions for SCD within clinical networks of CONSA partners and assess trial implementation. Outcomes will be evaluated from data collected using a shared patient registry. Standardized trial procedures will be implemented among designated birth populations in 7 African countries whose programs met eligibility criteria. Treatment protocol includes administering antibacterial and antimalarial prophylaxis and standard childhood vaccinations against infections commonly affecting children with SCD. Infants with a positive screen and confirmation of SCD within the catchment areas defined by each consortium partner will be enrolled in the clinical intervention protocol and followed regularly until age of 5 years. Effectiveness of these early interventions, along with culturally appropriate family education and counseling, will be evaluated by comparing U5M in the enrolled cohort to estimated preprogram data. Here, we describe the methodology planned for this trial.

Sex-related differences in clinical outcomes among patients with myocardial infarction with nonobstructive coronary artery disease: A systematic review and meta-analysis.

BACKGROUND: Among patients who present with acute myocardial infarction (MI), 2-6% are found to have non-obstructive coronary arteries (NOCA). Patients with MINOCA are more commonly women and present at a younger age (51-59 years). The influence of sex on adverse event rates remains unclear. METHODS: PubMed, MEDLINE, CENTRAL (Cochrane Central Register of Controlled Trials), EMBASE, EBSCO, Web of Science and CINAHL databases were searched for trials comparing gender differences in clinical outcomes among patients with MINOCA from inception through April 10, 2022. The primary endpoint of the study was composite major adverse clinical events (MACE) including all-cause mortality, non-fatal MI, stroke, and cardiovascular readmissions, and secondary endpoints were the individual components of the MACE. RESULTS: Seven studies with a total of 28,671 MINOCA patients were included (n = 11,249 men and n = 17,422 women) over a mean follow-up of 2 years. Women had more MACE than men (10.1% vs. 9.1%, OR 1.15, 1.04-1.23, I2 = 44.7%). Among secondary endpoints, only the incidence of stroke was higher in women (3.5% vs. 2.2%, OR 1.3, 1.01-1.68, I2 = 0%). All-cause mortality, non-fatal MI, and cardiovascular readmissions were not significantly different between the two groups. CONCLUSIONS: We hypothesize that small vessel disease associated with MINOCA drives MACE in women and the diminishing influence of estrogen, hypercoagulability and underprescribing could contribute to the differences sex-related outcomes.

Point of care ultrasound detection of thrombus straddling a patent foramen ovale in a patient with acute chest syndrome.

Patients with sickle cell disease can develop acute chest syndrome and are at high risk of developing pulmonary thrombosis. We report a case of a young woman with sickle cell disease who was hospitalized for vaso-occlusive crisis and subsequently developed worsening acute chest syndrome and stroke, discovered on point of care ultrasound to have right heart failure and a thrombus straddling a patent foramen oval. POCUS is highly specific for the detection of right heart dilation/dysfunction and should be a routine component of the assessment of acutely decompensating patients.

Inducing Vascular Grammars for Anomaly Classification in Brain Angiograms.

As machine learning is used to make strides in medical diagnostics, few methods provide heuristics from which human doctors can learn directly. This work introduces a method for leveraging human observable structures, such as macroscale vascular formations, for producing assessments of medical conditions with relatively few training cases, and uncovering patterns that are potential diagnostic aids. The approach draws on shape grammars, a rule-based technique, pioneered in design and architecture, and accelerated through a recursive subgraph mining algorithm. The distribution of rule instances in the data from which they are induced is then used as an intermediary representation enabling common classification and anomaly detection approaches to identify indicative rules with relatively small data sets. The method is applied to seven-tesla time-of-flight angiography MRI (n = 54) of human brain vasculature. The data were segmented and induced to generate representative grammar rules. Ensembles of rules were isolated to implicate vascular conditions reliably. This application demonstrates the power of automated structured intermediary representations for assessing nuanced biological form relationships, and the strength of shape grammars, in particular for identifying indicative patterns in complex vascular networks.

Liver-to-lung microembolic NETs promote gasdermin D-dependent inflammatory lung injury in sickle cell disease.

Acute lung injury, referred to as the acute chest syndrome, is a major cause of morbidity and mortality in patients with sickle cell disease (SCD), which often occurs in the setting of a vaso-occlusive painful crisis. P-selectin antibody therapy reduces hospitalization of patients with SCD by ∼50%, suggesting that an unknown P-selectin-independent mechanism promotes remaining vaso-occlusive events. In patients with SCD, intraerythrocytic polymerization of mutant hemoglobin promotes ischemia-reperfusion injury and hemolysis, which leads to the development of sterile inflammation. Using intravital microscopy in transgenic, humanized mice with SCD and in vitro studies with blood from patients with SCD, we reveal for the first time that the sterile inflammatory milieu in SCD promotes caspase-4/11-dependent activation of neutrophil-gasdermin D (GSDMD), which triggers P-selectin-independent shedding of neutrophil extracellular traps (NETs) in the liver. Remarkably, these NETs travel intravascularly from liver to lung, where they promote neutrophil-platelet aggregation and the development of acute lung injury. This study introduces a novel paradigm that liver-to-lung embolic translocation of NETs promotes pulmonary vascular vaso-occlusion and identifies a new GSDMD-mediated, P-selectin-independent mechanism of lung injury in SCD.