Señales de sobrevida inducidas por el complejo IL-6/IL-6sR en el linaje megacariocítico: influencia de la mutación JAK2-V617F

La IL-6 actúa a través del receptor de membrana y del soluble (IL-6sR) que confiere sensibilidad a células sin receptor de membrana. Previamente reportamos aumento de IL-6sR en trombocitemia esencial (TE), una neoplasia mieloproliferativa (NM). En este trabajo se evaluó la acción del complejo IL-6/IL-6sR (COMP) comparado con la IL-6 en su capacidad de protección de la apoptosis de progenitores CD34+ normales y de NM y de activación de JAK/STAT en plaquetas normales y de NM. Se evaluó expresión de fosfatidilserina por marcación con anexina V y de caspasa 3 activada en células CD34+ de sangre periférica de NM y de cordón umbilical como control, y activación de JAK2 y STAT3 por western-blot con anticuerpos contra las proteínas fosforiladas y sin fosforilar. En conjunto, los progenitores CD34+ de pacientes y controles tuvieron menos apoptosis con COMP que con IL-6 (activación de caspasa 3 p=0.001, 7 normales, 4 pacientes; expresión de anexina V p=0.029, 6 normales, 5 pacientes; Rangos señalados Wilcoxon) La activación de JAK2 y STAT3 en plaquetas se evaluó calculando la relación (Rel) de intensidad de la banda de la proteína fosforilada respecto del total estimulada por COMP (RelCOMP) y por TPO (RelTPO), obteniéndose el cociente (R COMP/TPO). Los pacientes JAK2V617F + tuvieron aumento de R COMP/TPO del STAT3, 2.03 (0.45-3.03) (mediana y rango) (n=4), respecto de controles 0.63 (0.014- 0.8) (n=5) y pacientes no mutados, 0.75 (0.005-1.12) (n=5) (ANOVA p=0.018). La activación de JAK2 siguió una tendencia similar a STAT3 aunque no alcanzó diferencias significativas. Los resultados sugieren que el COMP es más efectivo que la IL-6 en la protección de la apoptosis de los progenitores CD34+. Esto junto al hallazgo de aumento de IL-6sR en TE, sugerirían que un mayor nivel de IL-6sR favorece la sobrevida de los progenitores megacariocíticos en NM. La protección ocurriría a través de JAK2 y STAT3 siendo más eficiente en pacientes JAK2V617F+.Fil: Chazarreta, Carlos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Goette, Nora Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Lev, Paola Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Salim, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Molinas, Felisa Concepción. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Marta, Rosana Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentin

Abnormal regulation of soluble and anchored IL-6 receptor in monocytes from patients with essential thrombocythemia

Objective: In a previous study, we found increased plasma soluble receptor for interleukin-6 (sIL-6R) levels in patients with essential thrombocythemia (ET) that could promote megakaryopoiesis through IL-6 binding and further interaction with the signal transducer gp130. Here we have searched for the cell source of sIL-6R within mononuclear cells in these patients and the underlying abnormalities involved in its overproduction. Materials and Methods: Thirty patients with the diagnosis of ET were studied. sIL-6R levels were measured by enzyme-linked immunosorbent assay technique in the supernatants of peripheral monocyte and lymphocyte cultures. Expression of membrane-anchored IL-6R was determined by flow cytometry. In order to study the mechanism of sIL-6R production, tumor necrosis factor−α protease inhibitor was added to specifically block IL-6R shedding. Gene expression of sIL-6R levels were evaluated by reverse transcription polymerase chain reaction. Results: Monocytes were the main source of sIL-6R. Besides, in ET patients, monocyte sIL-6R release was higher than that of controls (p = 0.0014). Lymphocytes enhanced monocyte sIL-6R production by cell-mediated contact in normal controls, but this cooperation could not be seen in patients. Membrane expression of IL-6R was increased after monocyte adhesion in ET. sIL-6R synthesis was upregulated in most patients, while messenger RNA was normal. Conclusions: Our results indicate that ET monocytes are responsible for sIL-6R overproduction within mononuclear cells through synthesis upregulation. In addition, the lack of cooperation of lymphocytes in monocyte sIL-6R production in ET could be due to a monocyte abnormality. The agonistic effect of sIL-6R on IL-6 action could contribute to the exacerbated megakaryocytic growth in ET.Fil: Goette, Nora Paula. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Lev, Paola Roxana. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Heller, Paula Graciela. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Glembotsky, Ana Claudia. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Chazarreta, Carlos Daniel. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Salim, Juan Pablo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Molinas, Felisa Concepcion. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Marta, Rosana Fernanda. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; Argentin

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Differential expression of SDF-1 receptor CXCR4 in molecularly defined forms of inherited thrombocytopenias

The SDF-1-CXCR4 axis plays an essential role in the regulation of platelet production, by directing megakaryocyte (MK) migration toward the vascular niche, thus allowing terminal maturation and proplatelet formation, and also regulates platelet function in an autocrine manner. Inherited thrombocytopenias (IT) comprise a spectrum of diverse clinical conditions caused by mutations in genes involved in platelet production and function. We assessed CXCR4 expression and SDF-1 levels in a panel of well-characterized forms of IT. Decreased surface CXCR4 levels were found in 8 of 27 (29.6%) IT patients by flow cytometry, including 4 of 6 patients with ANKRD26-RT, 3 of 3 patients with GPS and 1 of 6 patients with FPD/AML. Low CXCR4 levels were associated with impaired SDF-1-triggered platelet aggregation, indicating that this decrease is functionally relevant, whereas a normal platelet response was shown in patients harbouring preserved membrane CXCR4. Reduced CXCR4 was not due to decreased gene expression, as platelet RNA levels were normal or increased, suggesting a post-transcriptional defect. Increased ligand-induced receptor internalization was ruled out, as circulating SDF-1 levels were similar to controls. MK CXCR4 expression was normal, indicating that the defect in CXCR4 arises after the step of platelet biogenesis. In conclusion, the finding of defective CXCR4 expression specifically associated with certain IT disorders highlights the fact that abnormalities in several megakaryocytic regulators underlie IT pathogenesis and further reveal the heterogeneous nature of these conditions.Fil: Salim, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Glembotsky, Ana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Lev, Paola Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Marin Oyarzún, Cecilia Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Goette, Nora Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Molinas, Felisa Concepción. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Marta, Rosana Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Heller, Paula Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentin

Production of functional platelet-like particles by the megakaryoblastic DAMI cell line provides a model for platelet biogenesis

The aim of this study was to evaluate cell maturation and the platelet production capacity of the megakaryoblastic DAMI cell line, to characterize platelet-like particles produced and to investigate the mechanisms involved in their production. DAMI cell maturation was induced by phorbol myristate acetate (PMA) and thrombopoietin (TPO). Expression levels of GATA-1, Fli-1 and NF-E2 were evaluated using real-time PCR and western blot. Platelet-like particles were characterized by the presence of GPIb and GPIIb by flow cytometry, while the soluble fragment of GPIb, glycocalicin, was detected by enzyme immunoassay. Dense and alpha granules were evaluated by mepacrine staining and thrombospondin-1 detection, respectively, and by electron microscopy. Functional capacity of platelet-like particles was studied by measuring P-selectin membrane after thrombin stimulation by flow cytometry and actin polymerization using phalloidin-FITC by immunofluorescence. We found that stimulation of DAMI cells with high concentration of PMA and TPO induced the expression of transcription factors GATA-1 and Fli-1 followed by an increase in the isoform a of NF-E2. Mature DAMI cells give rise to extensions resembling proplatelets and later, produce platelet-like particles expressing GPIIb and GPIb on their surface and containing dense and alpha granules, which were confirmed by electron microscopy. Platelet functionality was demonstrated by the increase in P-selectin membrane expression after thrombin stimulation and by their ability to spread on fibrinogen matrices. DAMI cell line induced to differentiate into mature megakaryocytes is able to produce functional platelets providing a suitable model to study the mechanisms involved in platelet generation.Fil: Lev, Paola Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Goette, Nora Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Glembotsky, Ana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Laguens, Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Favaloro; ArgentinaFil: Cabeza Meckert, Patricia. Universidad Favaloro; ArgentinaFil: Salim, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Heller, Paula Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Pozner, Roberto Gabriel. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas "Mariano R. Castex"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marta, Rosana Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Molinas, Felisa Concepción. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentin

Impact of Global Economic Disparities on Practices and Outcomes of Chronic Peritoneal Dialysis in Children: Insights from the International Pediatric Peritoneal Dialysis Network Registry

♦ Background, Objectives, and Methods: The number of patients on chronic peritoneal dialysis (CPD) is increasing rapidly on a global scale. We analyzed the International Pediatric Peritoneal Dialysis Network (IPPN) registry, a global database active in 33 countries spanning a wide range in gross national income (GNI), to identify the impact of economic conditions on CPD practices and outcomes in children and adolescents. ♦ Results: We observed close associations of GNI with the fraction of very young patients on dialysis, the presence and number of comorbidities, the prevalence of patients with unexplained causes of end-stage kidney disease, and the rate of culture-negative peritonitis. The prevalence of automated PD increased with GNI, but was 46% even in the lowest GNI stratum. The GNI stratum also affected the use of biocompatible peritoneal dialysis fluids, enteral tube feeding, calcium-free phosphate binders, active vitamin D analogs, and erythropoiesis-stimulating agents (ESAs). Patient mortality was strongly affected by GNI (hazard ratio per $10 000: 3.3; 95$18 000) had higher serum parathyroid hormone (PTH) and lower serum calcium, and achieved lower hemoglobin concentrations. No impact of GNI was observed with regard to CPD technique survival or peritonitis incidence. ♦ Conclusions: We conclude that CPD is practiced successfully, albeit with major regional variation related to economic differences, in children around the globe. The variations encompass the acceptance of very young patients and those with associated comorbidities to chronic dialysis programs, the use of automated PD and expensive drugs, and the diagnostic management of peritonitis. These variations in practice related to economic difference do not appear to affect PD technique survival; however, economic conditions seem to affect mortality on dialysis and standardized height, a marker of global child morbidity