Diagnosis of Bone Marrow Necrosis following Severe Vaso-Occlusive Crisis in Patient with Compound Heterozygous Sickle Cell Disease.

Introduction: Bone marrow necrosis is a rare entity that can develop in context of a sickle cell disease vaso-occlusive crisis. Its physiopathology is related to an endothelial dysfunction taking place in bone marrow microvasculature. Case Presentation: A 30-year-old patient with history of compound heterozygous sickle cell disease was admitted following SARS-CoV-2 infection with fever and diarrhea. After initial favorable evolution, he developed a severe vaso-occlusive crisis with intense hemolysis and multi-organ ischemic complications. Patient then developed high fever and hypoxemia. With the suspicion of acute thoracic syndrome, a red blood cell exchange was performed. Respiratory symptoms ceased but patient persisted febrile with very high levels of acute phase reactants, persistent pancytopenia, and leucoerythroblastic reaction. An infectious cause was ruled out. Afterward, bone marrow aspiration and bone marrow biopsy showed a picture of bone marrow necrosis, which is an extremely rare complication of vaso-occlusive crisis but, paradoxically, more frequent in milder heterozygote cases of sickle cell disease. Ultimately, large deposits of complement membrane attack complex (particles C5b-9) were demonstrated after incubation of laboratory endothelial cells with activated plasma from the patient. Discussion: The clinical presentation and findings are consistent with a case of bone marrow necrosis. In this setting, the demonstration of complement as a potential cause of the endothelial dysfunction mimics the pattern of atypical hemolytic uremic syndrome and other microangiopathic anemias. This dysregulation may be a potential therapeutic target for new complement activation blockers.

Anoctamin 5 (ANO5) muscular dystrophy-three different phenotypes and a new histological pattern.

OBJECTIVE: Anoctamin 5 (ANO5) is a putative intracellular calcium-activated chloride channel. Recessive mutations in ANO5 may present from asymptomatic hyperCKemia and exercise-induced myalgia to proximal and/or distal muscle weakness. Here we describe the clinical, pathological, and molecular findings of three unrelated patients with ANO5-related muscular dystrophy. METHODS: In this retrospective study, we analyzed our database which includes 1700 muscle biopsies performed for diagnostic purposes from October 2004 to February 2019. Patients were attended by two myology experts, who performed and analyzed the muscle biopsies. Muscle biopsies were frozen in cooled isopenthane, cryostat sectioned, and routinely stained and reacted (minimum 16 stainings). A custom panel, including 115 genes (Nextera Rapid Capture, Illumina) and whole-exome sequencing analysis, was used for next-generation sequencing in cases without a definite pathological diagnosis. RESULTS: Three patients were diagnosed with ANO5-related muscular dystrophy, with all presenting the common exon 5 mutation c.191dup plus a compound heterozygous missense mutation. They showed three different phenotypes (distal myopathy, LGMD2L, and asymptomatic hyperCKemia). Curiously, all three muscle biopsies showed different patterns, but numerous ragged-red fibers with little endomysial inflammation and partial invasion cell by T lymphocytes were observed in one. CONCLUSION: ANO5-related muscular dystrophy is a heterogeneous disease with different clinical phenotypes as well as different histological patterns, which may even mimic a mitochondrial myopathy. The results of this study provide further knowledge of the clinical, histological, and pathological features related to ANO5 mutations.

Distinctive Biomarker Features in the Endotheliopathy of COVID-19 and Septic Syndromes.

BACKGROUND: Endotheliopathy is a key element in COVID-19 pathophysiology, contributing to both morbidity and mortality. Biomarkers distinguishing different COVID-19 phenotypes from sepsis syndrome remain poorly understood. OBJECTIVE: To characterize circulating biomarkers of endothelial damage in different COVID-19 clinical disease stages compared with sepsis syndrome and normal volunteers. METHODS: Patients with COVID-19 pneumonia (n = 49) were classified into moderate, severe, or critical (life-threatening) disease. Plasma samples were collected within 48 to 72 h of hospitalization to analyze endothelial activation markers, including soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1), von Willebrand Factor (VWF), A disintegrin-like and metalloprotease with thrombospondin type 1 motif no. 13 (ADAMTS-13) activity, thrombomodulin (TM), and soluble TNF receptor I (sTNFRI); heparan sulfate (HS) for endothelial glycocalyx degradation; C5b9 deposits on endothelial cells in culture and soluble C5b9 for complement activation; circulating dsDNA for neutrophil extracellular traps (NETs) presence, and α2-antiplasmin and PAI-1 as parameters of fibrinolysis. We compared the level of each biomarker in all three COVID-19 groups and healthy donors as controls (n = 45). Results in critically ill COVID-19 patients were compared with other intensive care unit (ICU) patients with septic shock (SS, n = 14), sepsis (S, n = 7), and noninfectious systemic inflammatory response syndrome (NI-SIRS, n = 7). RESULTS: All analyzed biomarkers were increased in COVID-19 patients versus controls (P < 0.001), except for ADAMTS-13 activity that was normal in both groups. The increased expression of sVCAM-1, VWF, sTNFRI, and HS was related to COVID-19 disease severity (P < 0.05). Several differences in these parameters were found between ICU groups: SS patients showed significantly higher levels of VWF, TM, sTNFRI, and NETS compared with critical COVID-19 patients and ADAMTS-13 activity was significantly lover in SS, S, and NI-SIRS versus critical COVID-19 (P < 0.001). Furthermore, α2-antiplasmin activity was higher in critical COVID-19 versus NI-SIRS (P < 0.01) and SS (P < 0.001), whereas PAI-1 levels were significantly lower in COVID-19 patients compared with NI-SIRS, S, and SS patients (P < 0.01). CONCLUSIONS: COVID-19 patients present with increased circulating endothelial stress products, complement activation, and fibrinolytic dysregulation, associated with disease severity. COVID-19 endotheliopathy differs from SS, in which endothelial damage is also a critical feature of pathobiology. These biomarkers could help to stratify the severity of COVID-19 disease and may also provide information to guide specific therapeutic strategies to mitigate endotheliopathy progression.

Progressive endothelial cell damage in correlation with sepsis severity. Defibrotide as a contender.

BACKGROUND: The vascular endothelium plays a key role in sepsis pathophysiology and the associated organ dysfunction. METHODS: We evaluated endothelial function in an experimental in vitro model of sepsis, using endothelial cells grown in the presence of serum from patients with septic syndromes (sepsis, severe sepsis, and septic shock), noninfectious systemic inflammatory response syndrome (NI-SIRS) and healthy volunteers. Experiments were performed in the absence and presence of defibrotide (DF) (100 µg/ml) to evaluate its potential protective effect. RESULTS: After exposure to patients' sera, there was a progressive endothelial cell activation in correlation with sepsis severity, with a proinflammatory and prothrombotic phenotype, exhibiting significantly increased expression of adhesion receptors at the surface (intercellular adhesion molecule-1, p < .05 and vascular cell adhesion molecule-1, p < .05); higher production and release to the extracellular matrix (ECM) of von Willebrand factor (p < .001); augmented thrombogenicity of the ECM toward platelets (p < .001); and increased phosphorylation of intracellular p38MAPK. DF prevented these changes in all groups. CONCLUSIONS: Markers of endothelial damage increased progressively in association with the severity of septic syndromes. The endothelium is therefore an important therapeutic target to prevent complications of sepsis. DF shows promising potential to modulate the endothelial damage associated with sepsis and may constitute a pharmacological tool to decrease its sequelae including multiorgan failure.