Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 6-year-old girl with sickle cell disease was admitted to the hospital with the diagnosis of the acute chest syndrome. The laboratory findings and the radionuclear lung scan supported a diagnosis of pulmonary infarction rather than pneumonia. She improved with intravenous fluids, oxygen, penicillin, and theophylline. The most likely explanation for the rapid resolution of the clinical syndrome, the chest x-ray, and lung scan abnormalities is that masses of sickled cells caused transient pulmonary vascular occlusion leading to perfusion defects and ischemia, and that the sickled cell thrombi were dislodged before the infarction occurred. To our knowledge, this phenomenon has not been described as a cause of the acute chest syndrome in sickle cell disease in children.
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PMID:Acute reversible pulmonary ischemia. A cause of the acute chest syndrome in sickle cell disease. 406 60

Recent clinical and experimental data suggest that nitric oxide (NO) may play a role in the pathogenesis and therapy of sickle cell disease. NO, a soluble gas continuously synthesized in endothelial cells by the NO synthase (NOS) enzyme systems, regulates basal vascular tone and endothelial function, and maintains blood oxygenation via hypoxic pulmonary vasoconstriction and reduced shunt physiology. These vital homeostatic processes may be impaired in sickle cell disease and contribute to its pathogenesis. Therapeutic NO inhalation exerts significant direct effects on the pulmonary vasculature to reduce pulmonary pressures and increase oxygenation that may prove beneficial in acute chest syndrome and secondary pulmonary hypertension. Delivery of NO bound to hemoglobin or in plasma may improve blood flow and hemoglobin saturation, and thus reduce ischemia-reperfusion injury. Other NO-related effects on adhesion molecule expression and fetal hemoglobin induction are of interest. While direct evidence for a clinical benefit of NO therapy in sickle cell disease has not been reported, studies are underway to determine if inhaled NO will reduce the substantial morbidity and mortality suffered by these patients.
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PMID:Nitric oxide therapy in sickle cell disease. 1160 68

In children with sickle cell disease (SCD), adenotonsillar hypertrophy or recurrent tonsillitis are frequently linked with an increased risk of obstructive sleep apnea, cerebrovascular ischemia, or frequent pain episodes and often require an adenoidectomy and/or tonsillectomy. Interventions designed to prevent these complications, control vaso-occlusive pain episodes, and avoid hospitalizations may reduce the significant personal and economic burden of SCD. This study compares episode recurrence and treatment costs for cerebrovascular ischemia, vaso-occlusive pain, acute chest syndrome (ACS), and obstructive sleep apnea in children who had an adenotonsillectomy (A/T surgery, N = 256; 11.7%) and a matched cohort of those who did not (N = 512; 23.3%) from a cohort of 2,194 children and adolescents with SCD from South Carolina's Medicaid system. A/T surgery was associated with a significantly reduced rate of visits over time for obstructive sleep apnea and cerebrovascular ischemia (e.g., stroke, transient ischemic attacks), but not with any change in the rate of visits for vaso-occlusive pain or ACS/pneumonia visits. The rate of mean acute (emergency and inpatient) service costs was significantly decreasing over time after an increase about the time the A/T surgery was performed. The cost-effectiveness of adenoidectomy and/or tonsillectomy for treating obstructive sleep apnea and preventing cerebrovascular ischemia without increasing vaso-occlusive pain episodes or long-term acute service costs in routine clinical practice settings was demonstrated. The matched control group of SCD patients without A/T surgery contained more patients with severe vaso-occlusive pain episodes, ACS visits, and higher mean total costs over time and appears to represent a different phenotype of children with SCD.
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PMID:Cost-effectiveness of adenotonsillectomy in reducing obstructive sleep apnea, cerebrovascular ischemia, vaso-occlusive pain, and ACS episodes in pediatric sickle cell disease. 2071 23

Sickle cell disease (SCD) is characterized by recurrent episodes of vaso-occlusion, resulting in tissue ischemia and end-organ damage. Inflammation is critical to the pathogenesis of vaso-occlusion and has been associated with SCD-related morbidity and mortality. Despite the impact of inflammation, no directed anti-inflammatory therapies for the treatment or prevention of vaso-occlusive events currently exist. Among individuals with SCD, asthma is a comorbid inflammatory condition that increases the risk of pain episodes, acute chest syndrome and death. Inflammation associated with asthma could augment the proinflammatory state of SCD, increasing episodes of vaso-occlusion. Leukotrienes are inflammatory mediators that play a prominent role in the pathogenesis of asthma and have been associated with SCD-related morbidity. Targeting inflammatory mediators, such as leukotrienes, is a promising approach for the development of novel therapies for the treatment of SCD. This review will examine the relationship between inflammation and vaso-occlusion, with particular focus on the leukotriene pathway.
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PMID:Leukotriene pathway in sickle cell disease: a potential target for directed therapy. 2108 95

A humanized murine sickle cell-disease (SCD) model (NY1DD) has been used to study ischemia/reperfusion injury (IRI) in sickle cell anemia, and iNKT cells (a very small subset of murine and human T cells) have been found to instigate such injury in this model. Furthermore, levels of activated iNKT cells are generally elevated in the circulation of patients with SCD. Because activated iNKT cells are rich in adenosine A2A receptors which, when agonized, down-regulate the inflammatory cytokine expression that characterizes the cells, we have conducted a phase 1 trial of a constant infusion of low-dose regadenoson (an adenosine analogue with high A2A receptor specificity) to determine its safety and the capacity of a safe dose to down-regulate circulating iNKT cells in patients with SCD. We have found two dose rates that are both safe and effective and now plan a controlled Phase 2B clinical trial to determine whether our highest dose, administered as a 48-hour constant infusion, will induce faster remission in both painful vaso-occlusive crisis (pVOC) and acute chest syndrome (ACS).
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PMID:Sickle cell disease (SCD), iNKT cells, and regadenoson infusion. 2330 99

Ischemia-reperfusion (I/R) physiology, also called reperfusion injury, instigates vascular and tissue injury in human disease states. This review describes why sickle cell anemia should be conceptualized in this fashion and how I/R physiology explains the genesis of characteristic aspects of vascular pathobiology and clinical disease in sickle cell anemia. The nature of I/R and its relevance to sickle cell anemia are discussed, with an emphasis on the acute chest syndrome, endothelial dysfunction with aberrant vasoregulation, circle of Willis vasculopathy, and inflammatory pain. Viewing sickle disease from this perspective elucidates defining pathophysiology and identifies a host of novel potential therapeutic targets.
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PMID:Ischemia-reperfusion injury in sickle cell anemia: relationship to acute chest syndrome, endothelial dysfunction, arterial vasculopathy, and inflammatory pain. 2458 61

In spite of significant strides in the treatment of sickle cell disease (SCD), SCD crises are still responsible for high morbidity and early mortality. While most patients initially seek care in the acute setting for a seemingly uncomplicated pain episode (pain crisis or vaso-occlusive crisis), this initial event is the primary risk factor for potentially life-threatening complications. The pathophysiological basis of these illnesses is end-organ ischemia and infarction combined with the downstream effects of hemolysis that results from red blood cell sickling. These pathological changes can occur acutely and lead to a dramatic clinical presentation, but are frequently superimposed over a milieu of chronic vasculopathy, immune dysregulation, and decreased functional reserve. In the lungs, acute chest syndrome is a particularly ominous lung injury syndrome with a complex pathogenesis and potentially devastating sequelae, but all organ systems can be affected. It is, therefore, critical to understand the SCD patients' susceptibility to acute complications and their risk factors so that they can be recognized promptly and managed effectively. Blood transfusions remain the mainstay of therapy for all severe acute crises. Recommendations and indications for the safest and most efficient implementation of transfusion strategies in the critical care setting are therefore presented and discussed, together with their pitfalls and potential future therapeutic alternatives. In particular, the importance of extended phenotypic red blood cell matching cannot be overemphasized, due to the high prevalence of severe complications from red cell alloimmunization in SCD.
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PMID:Crises in Sickle Cell Disease. 2683 99

Coronary vasospasm is a well-known entity causing acute chest syndrome and can lead to myocardial infarction, ventricular arrhythmias, and even sudden cardiac death. While there are extensive case series showing the association of coronary vasospasm with cocaine, studies reporting marijuana-induced coronary vasospasm are limited in number. We herein present a case of coronary vasospasm in a middle-aged African-American male who presented to the emergency department after an episode of syncope. His urine drug screen was positive only for marijuana. He had a transient elevation of ST segments on his EKG with concomitant wall motion abnormalities on echocardiogram and was later found to have vasospasm of coronary arteries on coronary angiogram without any evidence of focal atherosclerotic disease. Another interesting finding was the persistent inter-coronary communication or coronary arcade connecting the left circumflex artery to the right coronary artery. There was bi-directional flow through the inter-coronary communication and hence, we believe this communication prevented our patient from experiencing acute chest symptoms or myocardial infarction. It is important for the clinicians to recognize the association of marijuana with coronary vasospasm. At the same time, these patients should be treated as acute coronary syndromes until proven otherwise by ischemia evaluation.
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PMID:Marijuana-induced Coronary Vasospasm with Persistent Inter-coronary Connection: A Case Report and Review of Literature. 3149 13

Sickle cell disease (SCD) is among the most common genetic diseases in the United States, affecting approximately 100,000 people. In the United States, SCD is characterized by a shortened life expectancy of only about 50 years in severe subtypes, significant quality-of-life impairments, and increased healthcare utilization and spending. SCD is characterized by chronic hemolytic anemia, vaso-occlusion, and progressive vascular injury affecting multiple organ systems. The pathophysiology is directly related to polymerization of deoxygenated hemoglobin, leading to a cascade of pathologic events including erythrocyte sickling, vaso-occlusion, tissue ischemia, and reperfusion injury as well as hemolysis, abnormal activation of inflammatory and oxidative pathways, endothelial dysfunction, increased oxidative stress, and activation of coagulation pathways. These multifactorial abnormalities have both acute and chronic clinical consequences across multiple organ systems, including acute pain episodes, chronic pain syndromes, acute chest syndrome, anemia, stroke and silent cerebral infarcts, cognitive dysfunction, pulmonary hypertension, and a wide range of other clinical consequences. Hydroxyurea was the only approved treatment for SCD for nearly 2 decades; in 2017, L-glutamine oral powder was approved for the prevention of the acute complications of SCD. During the last several years there has been a dramatic increase in research into treatments that address distinct elements of SCD pathophysiology and even new curative approaches that provide new hope to patients and physicians for a clinically consequential disease that has long been neglected.
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PMID:Sickle cell disease: current treatment and emerging therapies. 3180 7

Sickle cell anemia is a unique disease dominated by hemolytic anemia and vaso-occlusive events. The latter trigger a version of ischemia/reperfusion (I/R) pathobiology that is singular in its origin, cyclicity, complexity, instability, perpetuity, and breadth of clinical consequences. Specific clinical features are probably attributable to local I/R injury (e.g., stroke syndromes) or remote organ injury (e.g., acute chest syndrome) or the systematization of inflammation (e.g., multifocal arteriopathy). Indeed, by fashioning an underlying template of endothelial dysfunction and vulnerability, the robust inflammatory systematization no doubt contributes to all sickle pathology. In this Review, we highlight I/R-targeting therapeutics shown to improve microvascular blood flow in sickle transgenic mice undergoing I/R, and we suggest how such insights might be translated into human therapeutic strategies.
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PMID:The multifaceted role of ischemia/reperfusion in sickle cell anemia. 3211 86


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