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.

Is the Endothelium the Missing Link in the Pathophysiology and Treatment of COVID-19 Complications?

Patients with COVID-19 present a wide spectrum of disease severity, from asymptomatic cases in the majority to serious disease leading to critical care and even death. Clinically, four different scenarios occur within the typical disease timeline: first, an incubation and asymptomatic period; second, a stage with mild symptoms due mainly to the virus itself; third, in up to 20% of the patients, a stage with severe symptoms where a hyperinflammatory response with a cytokine storm driven by host immunity induces acute respiratory distress syndrome; and finally, a post-acute sequelae (PASC) phase, which present symptoms that can range from mild or annoying to actually quite incapacitating. Although the most common manifestation is acute respiratory failure of the lungs, other organs are also frequently involved. The clinical manifestations of the COVID-19 infection support a key role for endothelial dysfunction in the pathobiology of this condition. The virus enters into the organism via its interaction with angiotensin-converting enzyme 2-receptor that is present prominently in the alveoli, but also in endothelial cells, which can be directly infected by the virus. Cytokine release syndrome can also drive endothelial damage independently. Consequently, a distinctive feature of SARS-CoV-2 infection is vascular harm, with severe endothelial injury, widespread thrombosis, microangiopathy, and neo-angiogenesis in response to endothelial damage. Therefore, endothelial dysfunction seems to be the pathophysiological substrate for severe COVID-19 complications. Biomarkers of endothelial injury could constitute strong indicators of disease progression and severity. In addition, the endothelium could represent a very attractive target to both prevent and treat these complications. To establish an adequate therapy, the underlying pathophysiology and corresponding clinical stage should be clearly identified. In this review, the clinical features of COVID-19, the central role of the endothelium in COVID-19 and in other pathologies, and the potential of specific therapies aimed at protecting the endothelium in COVID-19 patients are addressed.

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.

Ventiladores mecánicos de emergencia para la COVID-19 / Emergency Mechanical Ventilators for Covid-19

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Biostatistics Disruptive Acculturation Through Serious Gaming: A New Hope.

Biostatistics is one of the transversal subjects that all future doctors must acquire and master. Nonetheless, it is a subject that has the reputation of being difficult, which has not been able to be corrected even with the application of new pedagogical methods such as blended learning. We address this problem with our acculturative and disruptive approach in the form of a serious game scenario in clinical research that integrates biostatistics with our R4Web adapted tools. Our approach was launched in 2008 for the second year of medical school. Here we describe this LOE scenario for serious game including the biostatistics disruptive acculturation task and present its new international version.

Predictive performance of glomerular filtration rate estimation equations based on cystatin C versus serum creatinine values in critically ill patients.

PURPOSE: The predictive performance of glomerular filtration rate (GFR) estimation equations based on cystatin C versus serum creatinine (SCr) values in critically ill patients was evaluated. METHODS: A retrospective observational study was performed in the medical intensive care unit (ICU) of a university hospital from October 2006 through September 2007. All consecutively admitted critically ill patients older than 18 years who stayed in the ICU for more than 48 hours with a urinary bladder catheter in place were included in the study. Data collected included SCr, cystatin C, serum albumin, blood urea nitrogen, and 24-hour urine creatinine clearance [Formula: see text] levels. The following equations were also used to determine the estimated GFR that was compared with the reference [Formula: see text] for all patients in the study: Arnal-Dade using cystatin C, Cockcroft-Gault using actual body weight, Cockcroft-Gault using ideal body weight, Jelliffe, Modification of Diet in Renal Disease (MDRD), and four-variable version MDRD (MDRD-4). RESULTS: This study included 241 measurements corresponding to 131 critically ill patients. The cystatin C-based equation underestimated [Formula: see text], whereas overestimation by every SCr-based formula was observed in the whole cohort and in the [Formula: see text] subgroup; MDRD-4 was the most biased equation in every analysis. There were no significant differences in precision, except for great variability in the subgroup with a [Formula: see text] of <60 mL/min/1.73 m(2), where the MDRD equation showed better results than the cystatin C-based equation (33.5% versus 38.9%). No equations fulfilled concordance requirements with [Formula: see text]. CONCLUSION: A retrospective observational study showed no evidence of superiority of a cystatin C-based equation over SCr-based equations to estimate the GFR in an ICU population.

Pulmonary tumor thrombotic microangiopathy: report of 3 cases and review of the literature.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare clinical entity where tumor cell embolisms in pulmonary circulation induce thrombotic microangiopathy (TMA), respiratory failure, and subacute cor pulmonale.We describe 3 cases of PTTM that presented as the initial manifestation of metastatic gastric adenocarcinoma with TMA and pulmonary infiltrates.All 3 cases had similar clinical and laboratory features, which included moderate thrombocytopenia without renal failure, hemolysis with extremely high serum lactate dehydrogenase levels, leukoerythroblastosis in peripheral blood smear, altered coagulation tests, lymphadenopathies, and interstitial pulmonary infiltrates. All patients died within 2 weeks of diagnosis. Two cases were initially misdiagnosed as idiopathic thrombotic thrombocytopenic purpura and treated with plasma exchange with no response. One patient had bone marrow infiltration by malignant cells. Autopsies revealed PTTM associated with gastric disseminated adenocarcinoma (signet-ring cell type in 2 patients and poorly differentiated type in 1).PTTM should be considered in the differential diagnosis of patients with fulminant microangiopathic hemolytic anemia, such as atypical thrombotic thrombocytopenic purpura, mainly those with pulmonary infiltrates, disseminated intravascular coagulation, or Trousseau syndrome.

Effect of nitric oxide inhalation on gas exchange in acute severe pneumonia.

Inhaled nitric oxide (NO) causes selective pulmonary vasodilatation and may improve gas exchange. The study was aimed to evaluate the acute effects of inhaled NO on pulmonary gas exchange in severe unilateral pneumonia, where hypoxemia results from increased intrapulmonary shunt. We studied 8 patients without preexisting lung disease (59±18 yr; 4M/4F) with early unilateral severe pneumonia and respiratory failure. Pulmonary and systemic hemodynamics and gas exchange, including ventilation-perfusion (V;A/Q;) distributions, were measured at baseline and while breathing 5 and 40 parts per million (ppm) of NO. Inhaled NO caused a dose-dependent fall in pulmonary vascular resistance (by 12% and 21%, with 5 and 40ppm, respectively; p<0.01, each) and improvement of PaO2 (by 25% and 23%; p<0.05, each), owing to the reduction of intrapulmonary shunt (by 23% and 27%; p<0.05, each), without changes in the amount of perfusion to low V;A/Q; ratio alveolar units. Patients with greater baseline intrapulmonary shunt exhibited greater improvement in arterial oxygenation (r(2)=0.55, p<0.05). We conclude that low doses of inhaled NO improve pulmonary gas exchange in acute severe pneumonia.

Severe imported malaria in adults: retrospective study of 20 cases.

Severe imported malaria is an important problem in many countries in which this disease is not endemic. This retrospective study describes the characteristics of 20 adults with severe imported malaria admitted to our intensive care unit from 1991 through 2007. All episodes were caused by Plasmodium falciparum and all patients had returned from sub-Saharan Africa, except for one transfusion recipient. All persons were considered non-immune, and none had taken appropriate chemoprophylaxis. The median time between the initiation of symptoms and the diagnosis was seven days. Five patients died (mortality rate = 25%). A higher frequency of unrousable coma and acidosis and a higher median Apache II score at admission was noted in the persons who died. Mortality by severe malaria remains high despite high quality management, which highlights the importance of chemoprophylaxis and early diagnosis and treatment.

Genomic and functional characterization of stellate cells isolated from human cirrhotic livers.

BACKGROUND/AIMS: Hepatic stellate cells (HSCs) are believed to participate in liver fibrogenesis and portal hypertension. Knowledge on human HSCs is based on studies using HSCs isolated from normal livers. We investigated the phenotypic, genomic and functional characteristics of HSCs from human cirrhotic livers. METHODS: HSC were obtained from normal and cirrhotic human livers. Cells were characterized by immunocytochemistry and gene microarray analysis. Cell proliferation, Ca(2+) changes and cell contraction were assessed by 3H-thymidine incorporation and by using an epifluorescence microscope. RESULTS: HSCs freshly isolated from human cirrhotic livers showed phenotypical features of myofibroblasts. These features were absent in HSCs freshly isolated from normal human livers and become prominent after prolonged culture. HSCs from cirrhotic human livers markedly express genes involved in fibrogensis, inflammation and apoptosis. HSCs from normal livers after prolonged culture preferntially expressed genes related to fibrogenesis and contractility. Agonists induced proliferation, Ca(2+) increase and cell contraction in HSCs isolated from human cirrhotic livers. Response to agonists was more marked in culture-activated HSCs and was not observed in HSCs freshly isolated from normal livers. CONCLUSIONS: HSCs from human cirrhotic livers show fibrogenic and contractile features. However, the current model of HSCs activated in culture does not exactly reproduce the activated phenotype found in cirrhotic human livers.

Interacción farmacocinética entre el ácido valproico y el meropenem / Pharmacokinetic interaction between valproic acid and meropenem

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Human hepatic stellate cells show features of antigen-presenting cells and stimulate lymphocyte proliferation.

Following cell activation, hepatic stellate cells (HSCs) acquire proinflammatory and profibrogenic properties. We investigated whether activated HSCs also display immune properties. Here we show that cultured human HSCs express membrane proteins involved in antigen presentation, including members of the HLA family (HLA-I and HLA-II), lipid-presenting molecules (CD1b and CD1c), and factors involved in T-cell activation (CD40 and CD80). Exposure of HSCs to proinflammatory cytokines markedly up-regulates these molecules. Importantly, cells freshly isolated from human cirrhotic livers (in vivo activated HSCs) highly express HLA-II and CD40, suggesting that HSCs can act as antigen-presenting cells (APCs) in human fibrogenesis. We also explored whether human HSCs can efficiently process exogenous antigens. Activated HSCs internalize low- and high-molecular-weight dextran and transferrin, indicating that they can perform fluid-phase and receptor-mediated endocytosis. Moreover, HSCs can perform phagocytosis of macromolecules because they internalize latex particles as well as bacteria. Interestingly, both culture-activated and in vivo activated HSCs express high levels of CD68, a protein involved in antigen trafficking. Finally, we studied whether HSCs modulate T-lymphocyte proliferation. In basal conditions, coculture of irradiated HSCs barely induces allogeneic T-lymphocyte proliferation. However, cytokine-stimulated HSCs stimulate the allogeneic T-lymphocyte response in an HLA-II-dependent manner. In conclusion, human activated HSCs express molecules for antigen presentation, internalize macromolecules, and modulate T-lymphocyte proliferation. These results suggest that HSCs may play a role in the immune function of the liver.

Activated human hepatic stellate cells express the renin-angiotensin system and synthesize angiotensin II.

BACKGROUND & AIMS: The renin-angiotensin system plays an important role in hepatic fibrogenesis. In other organs, myofibroblasts accumulated in damaged tissues generate angiotensin II, which promotes inflammation and extracellular matrix synthesis. It is unknown whether myofibroblastic hepatic stellate cells, the main hepatic fibrogenic cell type, express the renin-angiotensin system and synthesize angiotensin II. The aim of this study was to investigate whether quiescent and activated human hepatic stellate cells contain the components of the renin-angiotensin system and synthesize angiotensin II. METHODS: Hepatic stellate cells were freshly isolated from normal human livers (quiescent hepatic stellate cells) and from human cirrhotic livers (in vivo activated hepatic stellate cells). Culture-activated hepatic stellate cells were used after a second passage of quiescent hepatic stellate cells. Angiotensinogen, renin, and angiotensin-converting enzyme were assessed by quantitative polymerase chain reaction. Angiotensin II production was assessed by enzyme-linked immunosorbent assay and immunohistochemistry. RESULTS: Quiescent hepatic stellate cells barely express the renin-angiotensin system components--angiotensinogen, renin, and angiotensin-converting enzyme--and do not secrete angiotensin II. In contrast, both in vivo activated hepatic stellate cells and culture-activated hepatic stellate cells highly express active renin and angiotensin-converting enzyme and secrete angiotensin II to the culture media. Mature angiotensin II protein is also detected in the cytoplasm of in vivo activated and culture-activated hepatic stellate cells. Growth factors (platelet-derived growth factor and epidermal growth factor) and vasoconstrictor substances (endothelin-1 and thrombin) stimulate angiotensin II synthesis, whereas transforming growth factor-beta and proinflammatory cytokines have no effect. Vasodilator substances markedly attenuate the effect of endothelin-1. CONCLUSIONS: After activation, human hepatic stellate cells express the components of the renin-angiotensin system and synthesize angiotensin II. These results suggest that locally generated angiotensin II could participate in tissue remodeling in the human liver.