Multiple Life-threatening Complications Research Articles

Seroprevalence of Hepatitis B and Hepatitis C in People with Haemophilia at a Tertiary Care Centre, Assam, India: A Cross-sectional Study

Introduction: Prior to the advent of recombinant factor products, the treatment of haemophilia was mainly based on the administration of direct blood products like whole blood, Fresh Frozen Plasma (FFP), and cryoprecipitates. This led to a high incidence of transfusion-transmitted infections like Hepatitis B, Hepatitis C, and Human Immunodeficiency Virus (HIV) . Aim: To study the seroprevalence of Hepatitis B and Hepatitis C in people with haemophilia at Assam Medical College. Materials and Methods: This cross-sectional observational study was conducted at Assam Medical College, Dibrugarh, Assam on 73 haemophilia patients in the month of November 2023. Ethical clearance and informed consent were obtained. Demographic details and treatment-related history were taken, and blood samples were analysed to assess the seroprevalence of Australian antigen (HBsAg) and anti-HCV. The prevalence of Hepatitis B and C was studied with respect to the severity of the disease and treatment received. Statistical analysis was performed using Statistical Packages for Social Sciences (SPSS) version 17.0, and the level of significance was set at (p<0.05). Results: Out of the 73 patients included in the study, 62 participants (84.9%) had haemophilia A, while rest 11 (15.1%) had haemophilia B. The participants were distributed based on the severity of the disease into mild, moderate, and severe categories. Out of the 73 patients, 14 patients (19.2%), 20 patients (27.4%), and 39 patients (53.4%) belonged to the mild, moderate, and severe categories, respectively. Most of the patients belonged to the age of less than 30 years and highest number of patients in the age group of 11-20 years (35.7%). The overall positivity for Hepatitis B and C among all haemophilia patients was 1.4% and 5.5%, respectively. The prevalence of both Hepatitis B and C was higher in patients who had the severe form of haemophilia. Out of the 35 patients who received only recombinant factors, only one showed seropositivity for anti-HCV, whereas three patients were detected to be anti-HCV positive and one patient to be HBsAg positive among 38 patients who received both factors and FFP/ cryoprecipitates in their lifetime. Conclusion: Haemophilia patients are at a higher risk of developing transfusion-transmitted infections, which can cause multiple life-threatening complications. These complications can be easily prevented by early screening and early initiation of treatment. People with the severe form of the disease, especially those with a history of receiving direct blood products, are more prone to developing these infections. However, with the advent of recombinant factors, the incidence has come down.

Precise Terminology and Specified Catheter Insertion Length in Ultrasound-Guided Infraclavicular Central Vein Catheterization.

Background and Objectives: As the latest research encourages the ultrasound-guided infraclavicular central venous approach, due to the lateral puncture site displacement, in comparison to the anatomical landmark technique based on subclavian vein catheterization, the need to re-calculate the optimal catheter insertion length and possibly to rename the punctuated vessel emerges. Although naming a particular anatomical structure is a nomenclature issue, a suboptimal catheter position can be associated with multiple life-threatening complications and must be avoided. The main study objective is to determine the optimal catheter insertion length by the most proximal ultrasound-guided, in-plane infraclavicular central vein approach, to compare results with the anatomical landmark technique based on subclavian vein catheterization and to clarify the punctuated anatomical structure. Materials and Methods: 109 patients were enrolled in this study. All procedures were performed according to the same catheterization protocol. In order to determine optimal insertion length, chest X-ray scans with an existing catheter were performed. The definition of punctuated vessel was based on computer tomography and evaluated by radiologists. Independent predictors for optimal insertion length were identified, prediction equations were generated. Results: The optimal catheter insertion length is approximately 1.5 cm longer than estimated by Pere's formula and can be accurately calculated based on anthropometric data. Computed tomography revealed: five cases with subclavian vein puncture and three cases with axillary vein puncture. Conclusions: Even the most proximal ultrasound-guided infraclavicular central vein access does not guarantee subclavian vein catheterization. A more accurate term could be infraclavicular central venous access, with the implication that the entry point could be through either subclavian or axillary veins. The optimal insertion length is approximately 1.5 cm deeper than the length determined for the anatomical landmark technique based on subclavian vein catheterization.

Reconstruction of posterior dislocation of the sternoclavicular joint with nonabsorbable No. 5 ethibond sutures

Posterior sternoclavicular joint dislocation (PSCJD) is rare. It is usually due to contact sports or trauma and is often associated with multiple life-threatening complications. We report a case of a Kabaddi player (an Indian contact sport) who was pushed by an opponent and fell on his right shoulder. The patient complained of right shoulder pain and visible deformity over the right sternal area. After initial X-rays, the right posterior dislocation of the sternoclavicular joint was confirmed with computed tomography scan. After the attempts of closed reduction failed, open reduction and internal fixation were done with a double loop of No. 5 ethibond sutures. Excellent results can be achieved in PSCJD using open reduction and reconstruction techniques with double-stranded 5.0 ethibond nonabsorbable sutures.

RF36 | PSUN79 Prolonged Stimulation of β-Adrenergic Receptors in Human Brown and White Adipocytes Increases and then Decreases Metabolic Activity

Abstract Background Obesity results from excess adipose triglyceride storage and leads to multiple life-threatening complications that may be amenable to novel pharmacological therapies. Both human white and brown adipocytes express β1-, β2-, and β3-adrenergic receptors (β-AR's), and stimulation of each activates converging signaling pathways that regulate essential metabolic and cellular functions. Clinical data indicate that acute and chronic stimulation of the β3-AR with the selective agonist mirabegron increases lipolysis and thermogenesis, thereby making β3-AR activation a promising target to improve obesity-related metabolic disease. Purpose In this study, we evaluated in vitro the short-term and prolonged activation of β3-ARs via mirabegron and compared the effects to the activation of β1- and β2-AR. Methods Functional cellular assays such as lipolysis and cellular respiration, were measured in immortalized human white (hWA) and brown (hBA) adipocytes derived from the superficial and deep neck depots, respectively. Cells were treated for 6 h (short-term) and 24 h (prolonged) with mirabegron (β3-AR agonist), dobutamine (β1-AR agonist), terbutaline (β2-AR agonist) and isoproterenol (non-selective β-AR agonist). One-way ANOVA was used for statistical analysis. Findings In hWA, only short-term activation of the β2-AR induced lipolysis (1.8-fold increase, P=0.0002), while in hBA, both the β2-AR (1.5-fold increase, P=0.04) and β3-AR (1.6 fold increase, P=0.002) increased lipolysis with 6h treatment, as compared to the vehicle. By 24h, lipolysis was blunted in both cell types, likely due to agonist-induced desensitization and downregulation. Distinct from the lipolytic effects ofβ-AR activation, the basal oxygen consumption rate (OCR) was not significantly different among hBA and hWA treated acutely and chronically with each of the three selective β-ARs and positive control isoproterenol. However, in hBA only, prolonged activation of all three β-AR's lowered maximal mitochondrial respiration (isoproterenol: 25% decrease, P=0.0004; dobutamine: 25% decrease, P=0.0003; terbutaline: 26% decrease, P=0.0004; mirabegron: 38% decrease, P<0.0001, respectively). No significant changes in OCR parameters were detected in hWA. Conclusion In hBA, acute stimulation of either the β2-AR or β3-AR induces lipolysis. Prolonged exposure to β-agonists comparably lowers maximal cellular respiration, suggesting that all β-AR's are subject to agonist-induced desensitization. Moreover, continuous activation of lipolysis may deplete the intracellular fatty acid pool necessary for mitochondrial oxidative respiration. These responses will need to be addressed before novel adrenergic activators can be utilized to reduce triglyceride stores and treat obesity-related metabolic disease. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m., Monday, June 13, 2022 1:00 p.m. - 1:05 p.m.

Difficulties in the Treatment of Complications and Rehabilitation after COVID-19. A Clinical Case

The severe course of the new coronavirus infection (COVID-19) is associated with multiple life-threatening complications that lead to delayed initiation of active rehabilitation and unfavorable long-term treatment outcomes. Tracheoesophageal fistula is one of these complications. The specific feature of this event in COVID-19 is delayed tissue regeneration which requires a non-standard approach to management of such patients.The article presents a clinical case of a pregnant patient after a complicated severe course of COVID-19 with the development of tracheoesophageal fistula, sepsis, and weakness syndrome acquired in ICU. The combination of complications of the disease led to a prolonged (about five months) period of rehabilitation.Modern standard components of intensive therapy of such patients including regular monitoring of endotracheal/tracheostomy tube cuff pressure, dynamic assessment of nutritional status and its correction, rational antimicrobial therapy, screening of psychiatric disorders and early rehabilitation, will minimize the number of both early and delayed complications of COVID-19.

Assessment of Medication Adherence and Health-Related Quality of Life in Chronic Liver Disease Patients

Cirrhosis is a growing cause of morbidity and mortality in developed countries. It is associated with multiple life-threatening complications. Improving medication adherence could have a greater impact on the health of the population. Health-Related Quality of Life (HRQoL) has become a common outcome indicator in clinical and epidemiological studies. It is a multidimensional concept that includes self-reported measures of one's physical and mental health as well as their social well-being. This study aimed to assess the HRQoL and medication adherence in Chronic Liver Disease (CLD) patients. Medication adherence was determined using the Adherence to Refills and Medication Scale (ARMS) and RAND's SF-36 was used to assess HRQoL. A total of 102 Chronic Liver Disease patients were enrolled in the study, the majority of whom belonged to Child-Turcotte-Pugh class C (45.1%). The majority of the patients had a history of alcohol consumption (77.5%). The total average of four dimensions under PCS and MCS of SF-36 was 45.49 and 72.89 respectively and the overall average of all domains was 59.19. Concerning the Child-Turcotte-Pugh score of the patients, a significant correlation was obtained between physical functioning and RLPH domains. ARMS score had a significant impact on 3 of the PCS and all MCS domains of SF-36, indicating that the patient's medication adherence has an important role in HRQoL.

Federal clinical guidelines. Primary immunodeficiency: severe combined immunodeficiency

Severe combined immunodeficiency (SCID) is the most life-threatening form of primary immunodeficiency, fatal within the first years of life if hematopoietic stem cell transplantation (HSCT) is not performed. Early diagnosis is crucial for prevention of multiple life-threatening complications, which in turn allows for successful HSCT. Current publication contains clinical recommendations for diagnosis of SCID and its complications, complex treatment, including HSCT, prenatal diagnostics and genetic family counselling.

Imaging evaluation using computed tomography after ascending aortic graft repair.

Prosthetic aortic graft repair is employed in the management of various conditions such as annuloaortic ectasia, ascending aortic aneurysm, type A aortic dissection, and aortic root abscess. Correct interpretation of post-surgical prosthetic graft complications requires familiarity with the expected normal cross-sectional imaging appearance as well knowledge of additional surgical materials used in the repair, which could influence the imaging appearance. Multiple life-threatening complications of a prosthetic ascending aortic graft can be seen in the aorta and vicinity of the operative field. Complications can arise from involvement of the prosthetic aortic graft per se or secondary involvement of the coronary arteries, mediastinum, and sternotomy site. The optimal imaging protocol using multidetector computed tomography allows accurate interpretation of the expected benign postoperative changes as well as complications associated with the prosthetic graft, and differentiation of true complications from their mimickers. This review focuses on the normal imaging appearance of a prosthetic aortic graft on multidetector computed tomography, and imaging evaluation of multiple post-surgical complications that could arise after repair of the ascending aorta and the aortic valve.

An autoimmune storm: A case based literature review of successful management of lupus-polymyositis overlap syndrome complicated by multiple organ failure

Overlap syndromes of Connective tissues diseases is a rare and under-studied disorder. This syndrome can be complicated by multiple life-threatening complications like hepatitis, pancreatitis, macrophage activation syndrome and Acute Respiratory Distress syndrome. We report a 22-year-old Hispanic male with no remarkable past medical history who presented to the hospital with abdominal pain, myalgia, arthralgia, and persistent fever for two weeks and was found to have tachycardia, pancytopenia, transaminitis and an elevated lipase. The patient was initially evaluated for acute pancreatitis and hepatitis due to binge drinking and presumptive viral infection. Infectious work up was unrevealing, and the patient continued to deteriorate. The autoimmune panel came back significant for highly elevated Antinuclear Antibody (ANA) and Anti Double Stranded DNA antibody (dsDNA), low complement, high inflammatory markers, ferritin, elevated Creatine Kinase (CK), positive Anti Mi 2 antibody, low Natural Killer (NK) cell activity and elevated CD25. Patient was subsequently diagnosed with Lupus- Polymyositis overlap syndrome. Acute lupus flare was considered as the trigger for pancreatitis and hepatitis. The hospital course was complicated by Acute Respiratory Distress Syndrome (ARDS) due to Lupus pneumonitis, encephalopathy, and Macrophage Activation Syndrome (MAS). Patient was treated successfully with steroid pulse therapy, Cyclophosphamide, plasmapheresis, artificial ventilation, and extracorporeal membrane oxygenation (ECMO). We believe that this case is unique as it represented a diagnostic challenge as the Lupus-Polymyositis overlap syndrome is a rare entity, and it initially manifested in an extensively complicated pattern which is unusual. Moreover, this case was not only a diagnostic challenge but also a treatment conundrum due to multiple life-threatening complications the patient had during this hospitalization. In this review, we intend to discuss the management of this challenging and rarely reported connective tissue disease overlap syndrome.

Survival of a Male Infant with a Familial Xp11.4 Deletion Causing Ornithine Transcarbamylase Deficiency.

Ornithine transcarbamylase (OTC) deficiency is well known to cause severe neonatal hyperammonemia in males with absent enzyme activity. In families with large deletions of the X chromosome involving OTC and other contiguous genes, male infants appear to have an even more severe course. Notably, there are no published reports of these males surviving to liver transplant, even in cases where the diagnosis was known or suspected at birth. We describe two male newborns and their mother who all have a 1.5-Mb deletion of Xp11.4 encompassing the genes TSPAN7, OTC, and part of RPGR. The first child succumbed to his illness on his fourth day of life. His younger brother was diagnosed prenatally, and with early aggressive treatment, he survived the neonatal period. He suffered multiple life-threatening complications but stabilized and received a liver transplant at 7months of age. This report demonstrates both the possibility of survival and the complications in caring for these patients.

Transapical transcatheter aortic valve implantation in a patient with small body weight complicated by severe hypotension: An enigma successfully solved by echocardiography

Introduction. Transcatheter aortic valve implantation is currently considered an alternative treatment for older patients with severe aortic valve stenosis and increased surgical risk, but can be associated with multiple life-threatening complications. Case outline. An 83-year-old woman with severe symptomatic aortic stenosis, body weight of 29 kg and body surface area of 1.1 m2 underwent transcatheter aortic valve implantation via transapical access. Severe hypotension occurred before the valve implantation, due to temporary distortion of the mitral valve apparatus by stiff wire, leading to acute mitral regurgitation. This complication was immediately recognized by continuous transesophageal echocardiography and managed by simple wire retrieval instead of applying mechanical circulatory support. After rewiring and predilatation of the stenotic aortic valve, a 23 mm balloon-expandable transcatheter stent-prosthetic valve was successfully implanted. Conclusion. This case demonstrates that continuous imaging during transcatheter aortic valve implantation is key to rapid diagnosis of life-threatening complications, associated with the procedure, especially during the early learning curve in transapical approach.

The Problem of Atrial Fibrillation in Patients with Chronic Kidney Disease.

Chronic kidney disease (CKD) is associated with the risk of multiple life-threatening complications such as: progression to chronic renal failure and cardiovascular disease including coronary heart disease, heart failure and peripheral arterial disease. Also, atrial fibrillation (AF) is common in this group of patients. Factors contributing to the occurrence of AF in patients undergoing dialysis include: age, presence of coronary heart disease, echocardiographic abnormalities (low ejection fraction, atrial enlargement, valvular calcification, left ventricular hypertrophy), heart failure, chronic obstructive pulmonary disease, hypertension, stroke, malnutrition (low levels of albumin, total cholesterol and high-density lipoprotein (HDL), secondary hyperparathyroidism, low predialysis systolic blood pressure, duration of renal replacement therapy as well as the method of renal replacement therapy (more frequent in haemodialysis patients). The optimal management of thromboprophylaxis in patients with CKD and AF is complex due to the fact that in patients with CKD many physiologic mechanisms are altered which lead to substantial changes in haemostasis and thus this group of patients is characterized by an increased risk of thrombotic and haemorrhagic complications. Recommendations concerning the treatment of patients with AF do not include guidelines on how to manage patients with advanced CKD, due to the lack of large randomized trials assessing the efficacy and benefits of drugs in these patients. Patients with CKD and permanent, persistent, and paroxysmal AF ought to be treated as a group with high risk of bleeding and ischaemic stroke. In case of patients with no or only one moderate risk factors, it seems that anticoagulation with antiplatelet drugs can be considered as efficient therapy, while in patients with ≥2 risk factors an oral anticoagulation therapy may be used. During long-term treatment, the international normalized ratio (INR) must be controlled at least every 14 days and adjusted within a target range of 2.0-2.5. Moreover, renal function should be evaluated before initiation of direct thrombin or factor Xa inhibitors and re-evaluated when clinically indicated and at least annually.

Microbiology and risk factors associated with war-related wound infections in the Middle East.

The Middle East region is plagued with repeated armed conflicts that affect both civilians and soldiers. Injuries sustained during war are common and frequently associated with multiple life-threatening complications. Wound infections are major consequences of these war injuries. The microbiology of war-related wound infections is variable with predominance of Gram-negative bacteria in later stages. The emergence of antimicrobial resistance among isolates affecting war-related wound injuries is a serious problem with major regional and global implications. Factors responsible for the increase in multidrug-resistant pathogens include timing and type of surgical management, wide use of antimicrobial drugs, and the presence of metallic or organic fragments in the wound. Nosocomial transmission is the most important factor in the spread of multidrug-resistant pathogens. Wound management of war-related injuries merits a multidisciplinary approach. This review aims to describe the microbiology of war-related wound infections and factors affecting their incidence from conflict areas in Iraq, Syria, Israel, and Lebanon.

Bench to Bedside-Gene Therapy for Thalassemia and Sickle Cell Disease

The beta-hemoglobinopathies (beta-thalassemia and sickle cell disease) are the most prevalent inherited disorders worldwide and affect millions. Patients with beta-thalassemia major cannot survive without monthly, lifelong transfusions together with iron chelation therapy, and severe cases of sickle cell disease suffer from multiple life-threatening complications. Both categories of patients often have a shortened life expectancy in spite of supportive therapies, which impose an enormous financial burden on affected countries. The only available curative therapy is allogeneic hematopoietic stem cell transplantation, although most patients do not have an HLA-matched sibling donor, and those who do still risk graft rejection or graft-versus-host disease with associated morbidity and early mortality. This is why autologous gene therapy, by ex vivo transfer into the patient's own hematopoietic stem cells of a derivative of the normal beta-globin gene whose expression is appropriately regulated, is an attractive novel therapeutic modality. In addition, the very large number of known mutations causing beta-thalassemia makes gene therapy by gene addition ideally suited for regulatory product approval rather than the many mutation-specific products that would be required for site-specific gene correction. However, gene therapy of these disorders is especially challenging given the requirement for massive hemoglobin production in a lineage specific manner and the lack of selective advantage for corrected hematopoietic stem cells. During the past two decades, we and others have devised lentiviral vectors and applicable protocols to achieve the permanent correction of mouse models of the beta-hemoglobinopathies. The first approved human clinical trial worldwide resulted in the conversion to transfusion-independence of a patient with severe betaE/beta0-thalassemia, who required monthly transfusions since early childhood. This patient demonstrated prolonged transfusion-independent for over 8 years after gene therapy, and the initially identified partially dominant integration site (HMGA2) is no longer preeminent. A further optimized vector with high-grade purification is now being used in subsequent multi-center clinical trials in the USA, France, Australia, and Thailand both for beta-thalassemia major and severe sickle cell disease. As of the last public disclosure in June 2015, 34 subjects have been enrolled, of whom 12 and 2 patients with beta-thalassemia major and severe sickle cell disease, respectively, have undergone the gene therapy procedure. Currently analysable patients with beta-thalassemia major have rapidly decreased their transfusional needs or become completely transfusion-independent, often with near normal hemoglobin values and polyclonal distribution of vector bearing progenitors. Interestingly, conversion to transfusion-independence also occurred in a Cooley's anemia patient of the beta0/beta0 genotype. With regard to the first analysable patient with sickle cell disease, the anti-sickling globin variant utilized in the vector (βT87Q) is expressed at 40% level of all hemoglobin chains - a level well above the expected sickling inhibitory threshold - resulting in improvements in disease-specific biological markers and no hospitalization for sickle cell complications or acute episode despite weaning off transfusions, which this patient was receiving regularly for the prevention of stroke relapse. Prospects for bringing this novel therapeutic approach to medical practice and for complementary approaches to increase safety and efficacy will be discussed. DisclosuresLeboulch:bluebird bio: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.

Effect of Basti (oil enema) therapy for the management of cough in pertussis

Bordetella pertussis continues to circulate even in countries with good childhood vaccination coverage. Sporadic cases are still observed either due to no vaccination, incomplete vaccination or as a result of failure of vaccination. Though acute in nature it has a longer disease span with multiple life-threatening complications despite adequate management. This study was undertaken to study the effect of Sneha Basti (oil enema) in pertussis in relation to reduction in intensity of cough and complications of the disease when administered along with the conventional pharmacological therapy. Patients with the clinical picture mimicking pertussis were screened, investigated for pertussis and appropriate conventional pharmacological therapy of Erythromycin a preferred antimicrobial agent was started. Concurrently, Sneha Basti was administered to these two children. Both patients showed favourable results in terms of reduction of Kasa (cough) and the disease period with a faster recovery when compared to conventional therapy alone as has been observed routinely. No complications incurred during the complete disease span. It was concluded that if the pharmacological therapy is augmented with the complimentary systems of medicines, it can reduce the prolonged span and intensity of the disease and prevent other complications.

Metabolomic Profiles Reveal Sphingosine-1-Phosphate As a Novel Allosteric Modulator of Hemoglobin-Oxygen Affinity and a Key Contributor to Pathophysiology of Sickle Cell Disease

Abstract LBA-3Sickle cell disease (SCD) is a debilitating hemolytic disorder with high morbidity and mortality affecting millions of individuals worldwide. Although SCD was first identified a century ago, we still lack effective mechanism-based safe therapies to treat this disease. Thus, identification of specific molecules triggering sickling, the central pathogenic process of the disease, is extremely important to advance our understanding of the molecular basis for the pathogenesis of SCD and to develop novel therapeutics.Using non-biased metabolomic screening, we found that sphingosine-1-phosphate (S1P) is significantly elevated in the blood of SCD mice. Further analysis revealed that the activity of sphingosine kinase 1 (Sphk1, the enzyme that produces S1P) is significantly elevated in erythrocytes of SCD mice. Chronic treatment of SCD mice with a SphK1 inhibitor significantly attenuated sickling, hemolysis, inflammation and multiple tissue damage by reducing erythrocyte and plasma S1P levels. Erythrocyte S1P levels were further elevated following hypoxia/reoxygenation-induced acute sickle crisis (ASC) in SCD mice and blocking its elevation by a Sphk1 specific inhibitor significantly reduced hallmark features associated with ASC. As with SCD mice, we found that erythrocyte Sphk1 activity and erythrocyte and plasma S1P levels were significantly elevated in humans with SCD compared to normal individuals. Inhibition of SphK1 in cultured primary human erythrocytes isolated from SCD patients inhibited hypoxia-induced elevation of erythrocyte S1P levels and reduced sickling. Thus, we have revealed for the first time that SphK1-mediated S1P elevation in SCD erythrocytes is a key contributor to sickling in SCD and that Sphk1 inhibition can attenuate both acute and chronic sickling events and disease progression.S1P is an important signaling molecule regulating diverse biological processes. Although S1P is predominantly produced and stored in RBCs, nothing was known about the physiological role of S1P in normal RBCs or the pathophysiological role of S1P in SCD until we conducted a metabolomic screen. In an effort to determine the molecular mechanism underlying S1P-induced sickling, we unexpectedly found that S1P directly binds with Hb and results in a reduced Hb-O2 affinity. This finding led us to further discover that 2,3-diphosphoglycerate, another erythrocyte specific allosteric modulator, is required for S1P-mediated allosteric modulation and that these two endogenous heterotropic modulators work cooperatively to induce a substantial reduction in Hb-O2 affinity. Supporting the biochemical and functional findings, molecular modeling predicts that S1P binds near the water filled central cavity of HbA at a site that is different from the Hb-2,3-DPG binding site. Thus, our discovery adds a significant new chapter to erythrocyte physiology by revealing S1P is a novel allosteric modulator of Hb-O2 affinity and also providing a mechanism underlying S1P-mediated sickling by promoting the formation of deoxyHbS. Thus, the work reported here could be the foundation leading to future human trials and a possible therapy for SCD, a life-threatening hemolytic disorder for which the current treatment is extremely limited.The significance of our findings extends well beyond SCD. Our findings reveal a previously unrecognized important role for S1P in erythrocyte physiology and indicate a new concept for the regulation of O2 release from Hb under normal and sickle cell disease conditions. For SCD, elevated S1P is detrimental because reduced Hb-O2 affinity leads to more deoxygenation of HbS, increased sickling and subsequent multiple life-threatening complications. However, for normal erythrocytes, elevated S1P is likely beneficial by decreasing Hb-O2 affinity allowing for more O2 release to hypoxic tissues. Thus, for humans with normal Hb, if elevated S1P can induce O2 release to hypoxic tissues it may be a novel therapeutic target for a range of disorders, from chronic heart failure to diabetic retinopathy, traumatic blood loss, pulmonary disease and even cancer. In this way our findings reveal important novel opportunities to treat and prevent not only SCD but also multiple cardiovascular and pulmonary diseases associated with hypoxia. Thus, the impact of our novel finding is significant and enormous. Disclosures:No relevant conflicts of interest to declare.

Metabolomic Profiles Reveal Sphingosine-1-Phosphate As a Novel Allosteric Modulator of Hemoglobin-Oxygen Affinity and a Key Contributor to Pathophysiology of Sickle Cell Disease

Abstract LBA-3 Sickle cell disease (SCD) is a debilitating hemolytic disorder with high morbidity and mortality affecting millions of individuals worldwide. Although SCD was first identified a century ago, we still lack effective mechanism-based safe therapies to treat this disease. Thus, identification of specific molecules triggering sickling, the central pathogenic process of the disease, is extremely important to advance our understanding of the molecular basis for the pathogenesis of SCD and to develop novel therapeutics. Using non-biased metabolomic screening, we found that sphingosine-1-phosphate (S1P) is significantly elevated in the blood of SCD mice. Further analysis revealed that the activity of sphingosine kinase 1 (Sphk1, the enzyme that produces S1P) is significantly elevated in erythrocytes of SCD mice. Chronic treatment of SCD mice with a SphK1 inhibitor significantly attenuated sickling, hemolysis, inflammation and multiple tissue damage by reducing erythrocyte and plasma S1P levels. Erythrocyte S1P levels were further elevated following hypoxia/reoxygenation-induced acute sickle crisis (ASC) in SCD mice and blocking its elevation by a Sphk1 specific inhibitor significantly reduced hallmark features associated with ASC. As with SCD mice, we found that erythrocyte Sphk1 activity and erythrocyte and plasma S1P levels were significantly elevated in humans with SCD compared to normal individuals. Inhibition of SphK1 in cultured primary human erythrocytes isolated from SCD patients inhibited hypoxia-induced elevation of erythrocyte S1P levels and reduced sickling. Thus, we have revealed for the first time that SphK1-mediated S1P elevation in SCD erythrocytes is a key contributor to sickling in SCD and that Sphk1 inhibition can attenuate both acute and chronic sickling events and disease progression. S1P is an important signaling molecule regulating diverse biological processes. Although S1P is predominantly produced and stored in RBCs, nothing was known about the physiological role of S1P in normal RBCs or the pathophysiological role of S1P in SCD until we conducted a metabolomic screen. In an effort to determine the molecular mechanism underlying S1P-induced sickling, we unexpectedly found that S1P directly binds with Hb and results in a reduced Hb-O2 affinity. This finding led us to further discover that 2,3-diphosphoglycerate, another erythrocyte specific allosteric modulator, is required for S1P-mediated allosteric modulation and that these two endogenous heterotropic modulators work cooperatively to induce a substantial reduction in Hb-O2 affinity. Supporting the biochemical and functional findings, molecular modeling predicts that S1P binds near the water filled central cavity of HbA at a site that is different from the Hb-2,3-DPG binding site. Thus, our discovery adds a significant new chapter to erythrocyte physiology by revealing S1P is a novel allosteric modulator of Hb-O2 affinity and also providing a mechanism underlying S1P-mediated sickling by promoting the formation of deoxyHbS. Thus, the work reported here could be the foundation leading to future human trials and a possible therapy for SCD, a life-threatening hemolytic disorder for which the current treatment is extremely limited. The significance of our findings extends well beyond SCD. Our findings reveal a previously unrecognized important role for S1P in erythrocyte physiology and indicate a new concept for the regulation of O2 release from Hb under normal and sickle cell disease conditions. For SCD, elevated S1P is detrimental because reduced Hb-O2 affinity leads to more deoxygenation of HbS, increased sickling and subsequent multiple life-threatening complications. However, for normal erythrocytes, elevated S1P is likely beneficial by decreasing Hb-O2 affinity allowing for more O2 release to hypoxic tissues. Thus, for humans with normal Hb, if elevated S1P can induce O2 release to hypoxic tissues it may be a novel therapeutic target for a range of disorders, from chronic heart failure to diabetic retinopathy, traumatic blood loss, pulmonary disease and even cancer. In this way our findings reveal important novel opportunities to treat and prevent not only SCD but also multiple cardiovascular and pulmonary diseases associated with hypoxia. Thus, the impact of our novel finding is significant and enormous. Disclosures: No relevant conflicts of interest to declare.

Cardiovascular changes in cirrhosis: Pathogenesis and clinical implications

Liver cirrhosis is associated with a wide range of cardiovascular abnormalities including hyperdynamic circulation, cirrhotic cardiomyopathy, and pulmonary vascular abnormalities. The pathogenic mechanisms of these cardiovascular changes are multifactorial and include neurohumoral and vascular dysregulations. Accumulating evidence suggests that cirrhosis-related cardiovascular abnormalities play a major role in the pathogenesis of multiple life-threatening complications including hepatorenal syndrome, ascites, spontaneous bacterial peritonitis, gastroesophageal varices, and hepatopulmonary syndrome. Treatment targeting the circulatory dysfunction in these patients may improve the short-term prognosis while awaiting liver transplantation. Careful fluid management in the immediate post-transplant period is extremely important to avoid cardiac-related complications. Liver transplantation results in correction of portal hypertension and reversal of all the pathophysiological mechanisms that lead to the cardiovascular abnormalities, resulting in restoration of a normal circulation. The following is a review of the pathogenesis and clinical implications of the cardiovascular changes in cirrhosis.

Detrimental Role of Excess Adenosine-Mediated 2,3-Diphosphoglycerate Induction in Erythrocyte Sickling and Novel Mechanism-Based Therapies.

Abstract 906 Introduction:Sickle cell disease (SCD) is a devastating inherited hemolytic disorder due to a single missense mutation in the β-globin gene resulting in the production of hemoglobin S (HbS). Despite our knowledge of the molecular defect in HbS, we remain unable to control HbS polymerization and erythrocyte sickling under hypoxic conditions, which are central to the pathophysiology of the disease. Methods and Results:Here we report that adenosine, a cellular metabolite that is well known to be induced under hypoxic/ischemic conditions, is increased in the blood circulation of patients with SCD and in SCD transgenic (Tg) mice. To our surprise, we found that adenosine contributes to hypoxia-induced sickling of cultured erythrocytes from humans with SCD. Next, to evaluate the pathogenic role of increased adenosine in erythrocyte signaling in vivo, we took advantage of SCD transgenic (Tg) mice, a well accepted animal model of SCD. Intriguingly, treatment of SCD Tg mice with polyethylene glycol-modified adenosine deaminase (PEG-ADA) enzyme therapy to lower circulating adenosine levels reduced sickling and attenuated multiple tissue damage (including lung, kidney, liver and spleen) seen in SCD Tg mice. These findings revealed a previously unrecognized role for excess adenosine in sickling and the progression to multiple life-threatening complications. Next, by screening erythrocytes for small metabolites that are induced by adenosine and may contribute to sickling, we determined that 2,3-diphosphoglycerate (2,3-DPG), an erythroid specific metabolite known to promote O2 release from Hb, is elevated in erythrocytes of both SCD Tg mice and humans. Using both pharmacological and genetic approaches, we demonstrated that adenosine-mediated 2,3-DPG induction is through A2B receptor signaling and that this signaling pathway is a major contributor to hypoxia-induced erythrocyte sickling. Conclusion and Significance:Overall, we have identified for the first time that elevated adenosine induces 2,3-DPG via A2BR signaling and contributes to sickling in both human and mouse with SCD. Thus, our studies provide strong support for the new concept that adenosine-mediated 2,3-DPG induction is beneficial for normal erythrocytes by promoting O2release from Hb to hypoxic tissues. However, for SCD patients, the beneficial effect of adenosine-mediated 2,3-DPG induction becomes detrimental by inducing erythrocyte sickling due to 2,3-DPG mediated increased O2release and increased deoxyHbS polymerization. Our findings reveal a novel therapeutic possibility to treat and prevent sickling and progression to multiple life-threatening complications by targeting on the adenosine signaling pathway. Disclosures:No relevant conflicts of interest to declare.

Mortality of acute renal failure after rupture of abdominal aortic aneurysms

Acute renal failure of an abdominal aortic aneurysm is associated with an extremely poor chance of survival. We reviewed the cases of ruptured abdominal aortic aneurysm presenting between January 1, 1976 and June 1, 1979. Four patients developed oliguric acute renal failure and required hemodialysis. All patients survived despite multiple lifethreatening complications. The prognosis for acute renal failure after ruptured abdominal aortic aneurysm is better than previously recognized.