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Administration of oxygen microbubbles (OMBs) has been shown to increase oxygen and decrease carbon dioxide in systemic circulation, as well as reduce lung inflammation and promote survival in preclinical models of hypoxia caused by lung injury. However, their impact on microenvironmental oxygenation remains unexplored. Herein, we investigated the effects of intraperitoneal administration of OMBs in anesthetized rats exposed to hypoxic ventilation (FiO2 = 0.14). Blood oxygenation and hemodynamics were evaluated over a 2 h time frame, and then organ and tissue samples were collected for hypoxic and metabolic analyses. Data showed that OMBs improved blood SaO2 (~14%) and alleviated tissue hypoxia within the microenvironment of the kidney and intestine at 2 h of hypoxia. Metabolomic analysis revealed OMBs induced metabolic differences in the cecum, liver, kidney, heart, red blood cells and plasma. Within the spleen and lung, principal component analysis showed a metabolic phenotype more comparable to the normoxic group than the hypoxic group. In the spleen, this shift was characterized by reduced levels of fatty acids and 2-hydroxygluterate, alongside increased expression of antioxidant enzymes such as glutathione and hypoxanthine. Interestingly, there was also a shuttle effect within the metabolism of the spleen from the tricarboxylic acid cycle to the glycolysis and pentose phosphate pathways. In the lung, metabolomic analysis revealed upregulation of phosphatidylethanolamine and phosphatidylcholine synthesis, indicating a potential indirect mechanism through which OMB administration may improve lung surfactant secretion and prevent alveolar collapse. In addition, cell-protective purine salvage was increased within the lung. In summary, oxygenation with intraperitoneal OMBs improves systemic blood and local tissue oxygenation, thereby shifting metabolomic profiles of the lung and spleen toward a healthier normoxic state.

Aberrant coagulation in sickle cell disease (SCD) is linked to extracellular vesicle (EV) exposure. However, there is no consensus on the contributions of small EVs (SEVs) and large EVs (LEVs) toward underlying coagulopathy or on their molecular cargo. The present observational study compared the thrombin potential of SEVs and LEVs isolated from the plasma of stable pediatric and adult SCD patients. Further, EV lipid and protein contents were analyzed to define markers consistent with activation of thrombin and markers of underlying coagulopathy. Results suggested that LEVs—but not SEVs—from pediatrics and adults similarly enhanced phosphatidylserine (PS)-dependent thrombin generation, and cell membrane procoagulant PS (18:0;20:4 and 18:0;18:1) were the most abundant lipids found in LEVs. Further, LEVs showed activated coagulation in protein pathway analyses, while SEVs demonstrated high levels of cholesterol esters and a protein pathway analysis that identified complement factors and inflammation. We suggest that thrombin potential of EVs from both stable pediatric and adult SCD patients is similarly dependent on size and show lipid and protein contents that identify underlying markers of coagulation and inflammation.

IntroductionHuman and murine sickle cell disease (SCD) associated pulmonary hypertension (PH) is defined by hemolysis, nitric oxide depletion, inflammation, and thrombosis. Further, hemoglobin (Hb), heme, and iron accumulation are consistently observed in pulmonary adventitial macrophages at autopsy and in hypoxia driven rodent models of SCD, which show distribution of ferric and ferrous Hb as well as HO-1 and ferritin heavy chain. The anatomic localization of these macrophages is consistent with areas of significant vascular remodeling. However, their contributions toward progressive disease may include unique, but also common mechanisms, that overlap with idiopathic and other forms of pulmonary hypertension. These processes likely extend to the vasculature of other organs that are consistently impaired in advanced SCD.MethodsTo date, limited information is available on the metabolism of macrophages or monocytes isolated from lung, spleen, and peripheral blood in humans or murine models of SCD.ResultsHere we hypothesize that metabolism of macrophages and monocytes isolated from this triad of tissue differs between Berkley SCD mice exposed for ten weeks to moderate hypobaric hypoxia (simulated 8,000 ft, 15.4% O2) or normoxia (Denver altitude, 5000 ft) with normoxia exposed wild type mice evaluated as controls.DiscussionThis study represents an initial set of data that describes the metabolism in monocytes and macrophages isolated from moderately hypoxic SCD mice peripheral lung, spleen, and blood mononuclear cells.

Sickle cell anemia and β‐thalassemia intermedia are very different genetically determined hemoglobinopathies predisposing to pulmonary hypertension. The etiologies responsible for the associated development of pulmonary hypertension in both diseases are multi‐factorial with extensive mechanistic contributors described. Both sickle cell anemia and β‐thalassemia intermedia present with intra and extravascular hemolysis. And because sickle cell anemia and β‐thalassemia intermedia share features of extravascular hemolysis, macrophage iron excess and anemia we sought to characterize the common features of the pulmonary hypertension phenotype, cardiac mechanics, and function as well as lung and right ventricular metabolism. Within the concept of iron, we have defined a unique pulmonary vascular iron accumulation in lungs of sickle cell anemia pulmonary hypertension patients at autopsy. This observation is unlike findings in idiopathic or other forms of pulmonary arterial hypertension. In this study, we hypothesized that a common pathophysiology would characterize the pulmonary hypertension phenotype in sickle cell anemia and β‐thalassemia intermedia murine models. However, unlike sickle cell anemia, β‐thalassemia is also a disease of dyserythropoiesis, with increased iron absorption and cellular iron extrusion. This process is mediated by high erythroferrone and low hepcidin levels as well as dysregulated iron transport due transferrin saturation, so there may be differences as well. Herein we describe common and divergent features of pulmonary hypertension in aged Berk‐ss (sickle cell anemia) and Hbbth/3+ (intermediate β‐thalassemia) mice and suggest translational utility as proof‐of‐concept models to study pulmonary hypertension therapeutics specific to genetic anemias.

Macrophages are a heterogeneous population with both pro‐ and anti‐inflammatory functions play an essential role in maintaining tissue homeostasis, promoting inflammation under pathological conditions, and tissue repair after injury. In pulmonary hypertension, the M1 phenotype is more pro‐inflammatory compared to the M2 phenotype, which is involved in tissue repair. The role of macrophages in the initiation and progression of pulmonary hypertension is well studied. However, their role in the regression of established pulmonary hypertension is not well known. Rats chronically exposed to hemoglobin (Hb) plus hypoxia (HX) share similarities to humans with pulmonary hypertension associated with hemolytic disease, including the presence of a unique macrophage phenotype surrounding distal vessels that are associated with vascular remodeling. These lung macrophages are characterized by high iron content, HO‐1, ET‐1, and IL‐6, and are recruited from the circulation. Depletion of macrophages in this model prevents the development of pulmonary hypertension and vascular remodeling. In this study, we specifically investigate the regression of pulmonary hypertension over a four‐week duration after rats were removed from Hb + HX exposure with and without gadolinium chloride administration. Withdrawal of Hb + HX reversed systolic pressures and right ventricular function after Hb + Hx exposure in four weeks. Our data show that depleting circulating monocytes/macrophages during reversal prevents complete recovery of right ventricular systolic pressure and vascular remodeling in this rat model of pulmonary hypertension at four weeks post exposure. The data presented offer a novel insight into the role of macrophages in the processes of pulmonary hypertension regression in a rodent model of Hb + Hx‐driven disease.

Hypoxic pulmonary vasoconstriction (HPV) is a well-characterized vascular response to low oxygen pressures and is involved in life-threatening conditions such as high-altitude pulmonary edema (HAPE) and pulmonary arterial hypertension (PAH). While the efficacy of oral therapies can be affected by drug metabolism, or dose-limiting systemic toxicity, inhaled treatment via pressured metered dose inhalers (pMDI) may be an effective, nontoxic, practical alternative. We hypothesized that a stable water-in-perfluorooctyl bromide (PFOB) emulsion that provides solubility in common pMDI propellants, engineered for intrapulmonary delivery of pulmonary vasodilators, reverses HPV during acute hypoxia (HX). Male Sprague Dawley rats received two 10-min bouts of HX (13% O2) with 20 min of room air and drug application between exposures. Treatment groups: intrapulmonary delivery (PUL) of (1) saline; (2) ambrisentan in saline (0.1 mg/kg); (3) empty emulsion; (4) emulsion encapsulating ambrisentan or sodium nitrite (NaNO2) (0.1 and 0.5 mg/kg each); and intravenous (5) ambrisentan (0.1 mg/kg) or (6) NaNO2 (0.5 mg/kg). Neither PUL of saline or empty emulsion, nor infusions of drugs prevented pulmonary artery pressure (PAP) elevation (32.6 ± 3.2, 31.5 ± 1.2, 29.3 ± 1.8, and 30.2 ± 2.5 mmHg, respectively). In contrast, PUL of aqueous ambrisentan and both drug emulsions reduced PAP by 20–30% during HX, compared to controls. IL6 expression in bronchoalveolar lavage fluid and whole lung 24 h post-PUL did not differ among cohorts. We demonstrate proof-of-concept for delivering pulmonary vasodilators via aerosolized water-in-PFOB emulsion. This concept opens a potentially feasible and effective route of treating pulmonary vascular pathologies via pMDI.

Sickle cell disease (SCD) is an inherited hemolytic disorder, defined by a point mutation in the β-globin gene. Stress conditions such as infection, inflammation, dehydration, and hypoxia trigger erythrocyte sickling. Sickled red blood cells (RBCs) hemolyze more rapidly, show impaired deformability, and increased adhesive properties to the endothelium. In a proinflammatory, pro-coagulative environment with preexisting endothelial dysfunction, sickled RBCs promote vascular occlusion. Hepatobiliary involvement related to the sickling process, such as an acute sickle hepatic crisis, is observed in about 10% of acute sickle cell crisis incidents. In mice, ligation of CD40 with an agonistic antibody leads to a macrophage activation in the liver, triggering a sequence of systemic inflammation, endothelial cell activation, thrombosis, and focal ischemia. We found that anti-CD40 antibody injection in sickle cell mice induces a systemic inflammatory and hemodynamic response with accelerated hemolysis, extensive vaso-occlusion, and large ischemic infarctions in the liver mimicking an acute hepatic crisis. Administration of the tumor necrosis factor-α (TNF-α) blocker, etanercept, and the heme scavenger protein, hemopexin attenuated end-organ damage. These data collectively suggest that anti-CD40 administration offers a novel acute liver crisis model in humanized sickle mice, allowing for evaluation of therapeutic proof-of-concept.

Pulmonary hypertension may arise as a complication of chronic lung disease typically associated with tissue hypoxia, as well as infectious agents or injury eliciting a type 2 immune response. The onset of pulmonary hypertension in this setting (classified as Group 3) often complicates treatment and worsens prognosis of chronic lung disease. Chronic lung diseases such as chronic obstructive lung disease (COPD), emphysema, and interstitial lung fibrosis impair airflow and alter lung elastance in addition to affecting pulmonary vascular hemodynamics that may culminate in right ventricle dysfunction. To date, functional endpoints in murine models of chronic lung disease have typically been limited to separately measuring airway and lung parenchyma physiology. These approaches may be lengthy and require a large number of animals per experiment. Here, we provide a detailed protocol for combined assessment of airway physiology with cardiovascular hemodynamics in mice. Ultimately, a comprehensive overview of pulmonary function in murine models of injury and disease will facilitate the integration of studies of the airway and vascular biology necessary to understand underlying pathophysiology of Group 3 pulmonary hypertension.

Abstract Background Large-scale “omics” datasets have not been leveraged and integrated with functional analyses to discover potential drivers of cardiomyopathy. This study addresses the knowledge gap. Methods We coupled RNA sequence (RNA-Seq) variant detection and transcriptome profiling with pathway analysis to model drug refractory dilated cardiomyopathy (drDCM) using the BaseSpace sequencing hub and Ingenuity Pathway Analysis. We used RNA-Seq case-control datasets (n = 6 cases, n = 4 controls), exome sequence familial DCM datasets (n = 3 Italians, n = 5 Italians, n = 5 Chinese), and controls from the HapMap project (n = 5 Caucasians, and n = 5 Asians) for disease modeling and putative mutation discovery. Variant replication datasets: n = 128 cases and n = 15 controls. Source of datasets: NCBI Sequence Read Archive. Statistics: Pairwise differential expression analyses to determine differentially expressed genes and t-tests to calculate p-values. We adjusted for false discovery rates and reported q-values. We used chi-square tests to assess independence among variables, the Fisher’s Exact Tests and overlap p-values for the pathways and p-scores to rank network. Results Data revealed that ECHS1(enoyl-CoA hydratase, short chain 1(log2(foldchange) = 1.63329) hosts a mirtron, MIR3944 expressed in drDCM (FPKM = 5.2857) and not in controls (FPKM = 0). Has-miR3944-3p is a putative target of BAG1 (BCL2 associated athanogene 1(log2(foldchange) = 1.31978) and has-miR3944-5p of ITGAV (integrin subunit alpha V(log2(foldchange) = 1.46107) and RHOD (ras homolog family member D(log2(foldchange) = 1.28851). There is an association between ECHS1:11 V/A(rs10466126) and drDCM (p = 0.02496). The interaction (p = 2.82E-07) between ECHS1:75 T/I(rs1049951) and ECHS1:rs10466126 is associated with drDCM (p

G protein-coupled receptors (GPCRs) have originally been described as a family of receptors activated by hormones, neurotransmitters, and other mediators. However, in recent years GPCRs have shown to bind endogenous metabolites, which serve functions other than as signaling mediators. These receptors respond to fatty acids, mono- and disaccharides, amino acids, or various intermediates and products of metabolism, including ketone bodies, lactate, succinate, or bile acids. Given that many of these metabolic processes are dysregulated under pathological conditions, including diabetes, dyslipidemia, and obesity, receptors of endogenous metabolites have also been recognized as potential drug targets to prevent and/or treat metabolic and cardiovascular diseases. This review describes G protein-coupled receptors activated by endogenous metabolites and summarizes their physiological, pathophysiological, and potential pharmacological roles.

A new method for hemoglobin (Hb) deoxygenation, in suspension or within red blood cells (RBCs) is described using the commercial enzyme product, EC-Oxyrase®. The enzymatic deoxygenation method has several advantages over established deoxygenation methodologies, such as avoiding side reactions that produce methemoglobin (metHb), thus eliminating the need for an inert deoxygenation gas and airtight vessel, and facilitates easy re-oxygenation of Hb/RBCs by washing with a buffer that contains dissolved oxygen (DO). The UV-visible spectra of deoxyHb and metHb purified from human RBCs using three different preparation methods (sodium dithionite [to produce deoxyHb], sodium nitrite [to produce metHb], and EC-Oxyrase® [to produce deoxyHb]) show the high purity of deoxyHb prepared using EC-Oxyrase® (with little to no metHb or hemichrome production from side reactions). The oxyHb deoxygenation time course of EC-Oxyrase® follows first order reaction kinetics. The paramagnetic characteristics of intracellular Hb in RBCs were compared using Cell Tracking Velocimetry (CTV) for healthy and sickle cell disease (SCD) donors and oxygen equilibrium curves show that the function of healthy RBCs is unchanged after EC-Oxyrase® treatment. The results confirm that this enzymatic approach to deoxygenation produces pure deoxyHb, can be re-oxygenated easily, prepared aerobically and has similar paramagnetic mobility to existing methods of producing deoxyHb and metHb.

It is now well established that both inherited and acquired forms of hemolytic disease can promote pulmonary vascular disease consequent of free hemoglobin (Hb) induced NO scavenging, elevations in reactive oxygen species and lipid peroxidation. It has recently been reported that oxidative stress can activate NFkB through a toll-like receptor 9 (TLR9) mediated pathway; further, TLR9 can be activated by either nuclear or mitochondrial DNA liberated by stress induced cellular trauma. We hypothesis that Hb induced lipid peroxidation and subsequent endothelial cell trauma is linked to TLR9 activation, resulting in IL-6 mediated pulmonary smooth muscle cell proliferation. We examined the effects of Hb on rat pulmonary artery endothelial and smooth muscle cells (rPAEC and rPASMC, respectively), and then utilized TLR9 and IL6 inhibitors, as well as the Hb and heme binding proteins (haptoglobin (Hp) and hemopexin (Hpx), respectively) to further elucidate the aforementioned mediators. Further, we explored the effects of Hb in vivo utilizing endothelial cell (EC) specific myeloid differentiation primary response gene-88 (MyD88) and TLR9 null mice. Our data show that oxidized Hb induces lipid peroxidation, cellular toxicity (5.5 ± 1.7 fold; p≤0.04), increased TLR9 activation (60%; p = 0.01), and up regulated IL6 expression (1.75±0.3 fold; p = 0.04) in rPAEC. Rat PASMC exhibited a more proliferative state (13 ± 1%; p = 0.01) when co-cultured with Hb activated rPAEC. These effects were attenuated with the sequestration of Hb or heme by Hp and Hpx as well as with TLR9 an IL-6 inhibition. Moreover, in both EC-MyD88 and TLR9 null mice Hb-infusion resulted in less lung IL-6 expression compared to WT cohorts. These results demonstrate that Hb-induced lipid peroxidation can initiate a modest TLR9 mediated inflammatory response, subsequently generating an activated SMC phenotype.