Highlights d SARS-CoV2 infection elicits dynamic changes of circulating cells in the blood d Severe COVID-19 is characterized by increased metabolically active plasmablasts d Elevation of IFN-activated megakaryocytes and erythroid cells in severe COVID-19 d Cell-type-specific expression signatures are associated with a fatal COVID-19 outcome

Background-The aim of this study was to estimate the impact of thrombophilia on risk of first childhood stroke through a meta-analysis of published observational studies. Methods and Results-A systematic search of electronic databases (Medline via PubMed, EMBASE, OVID, Web ofScience, The Cochrane Library) for studies published from 1970 to 2009 was conducted. Data on year of publication, study design, country of origin, number of patients/control subjects, ethnicity, stroke type (arterial ischemic stroke [AIS], cerebral venous sinus thrombosis [CSVT]) were abstracted. Publication bias indicator and heterogeneity across studies were evaluated, and summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with fixed-effects or random-effects models. Twenty-two of 185 references met inclusion criteria. Thus, 1764 patients (arterial ischemic stroke [AIS], 1526; cerebral sinus venous thrombosis [CSVT], 238) and 2799 control subjects (neonate to 18 years of age) were enrolled. No significant heterogeneity was discerned across studies, and no publication bias was detected. A statistically significant association with first stroke was demonstrated for each thrombophilia trait evaluated, with no difference found between AIS and CSVT. Summary ORs (fixed-effects model) were as follows: antithrombin deficiency, 7.06 (95% CI, 2.44 to 22.42); protein C deficiency, 8.76 (95% CI, 4.53 to 16.96); protein S deficiency, 3.20 (95% CI, 1.22 to 8.40), factor V G1691A, 3.26 (95% CI, 2.59 to 4.10); factor II G20210A, 2.43 (95% CI, 1.67 to 3.51); MTHFR C677T (AIS), 1.58 (95% CI, 1.20 to 2.08); antiphospholipid antibodies (AIS) [CSVT]) is estimated to be between 2.6 and 6.4 per 100 000 per year, reflecting a trend toward a higher frequency in more current literature. 1-3 Underlying conditions in children with symptomatic cerebrovascular accidents include congenital heart malformations, hemolytic anemias, and collagen vascular diseases, as well as some rare inborn metabolic disorders. 4 In addition, risk factors include trauma and infectious diseases. Apart from acquired thrombophilic risk factors such as the presence of antiphospholipid antibodies, 5,6 inherited thrombophilia, particularly antithrombin, protein C, and protein S deficiency, variants of coagulation factor V (G1691A) and factor II (G20210A), and elevated lipoprotein(a), have been found in small case series and case-control studies to be associated with AIS or CSVT in infants and children. Furthermore, an association of the thermolabile MTHFR C677T genotype with stroke is controversial in both adults and children. 5353 In fact, the increased likelihood of having a blood clot in the vasculature is related to elevated homocysteine levels, and mutations in the MTHFR gene only exploit their effect by contributing to the elevated homocysteine plasma level. Because adequate folate levels essentially cancel out the impaired regulation of homocysteine induced by MTHFR mutations, not all people will develop high homocysteine levels. [53][54][55][56] , Editori...

Apoptotic cell death following injury of vascular endothelium is assumed to play an important role in the pathogenesis of atherosclerosis. In this report, we demonstrate that high density lipoproteins (HDL), a major anti-atherogenic lipoprotein fraction, protect endothelial cells against growth factor deprivation-induced apoptosis. HDL blocked the mitochondrial pathway of apoptosis by inhibiting dissipation of mitochondrial potential (⌬ m ), generation of reactive oxygen species, and release of cytochrome c into the cytoplasm. As a consequence, HDL prevented activation of caspases 9 and 3 and apoptotic alterations of the plasma membrane such as increase of permeability and translocation of phosphatidylserine. Treatment of endothelial cells with HDL induced activation of the protein kinase Akt, an ubiquitous transducer of anti-apoptotic signals, and led to phosphorylation of BAD, a major Akt substrate. Suppression of Akt activity both by wortmannin and LY-294002 or by a dominant negative Akt mutant abolished the anti-apoptotic effect of HDL. Two bioactive lysosphingolipids present in HDL particles, sphingosylphosphorylcholine and lysosulfatide, fully mimicked the survival effect of HDL by blocking the mitochondrial pathway of apoptosis and potently activating Akt. In conclusion, the present study identifies HDL as a carrier of endogenous endothelial survival factors and suggests that inhibition of endothelial apoptosis by HDLassociated lysosphingolipids may represent an important and novel aspect of the anti-atherogenic activity of HDL.

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the Childhood Stroke Study GroupBackground-The present study was performed to assess the association of prothrombotic risk factors and underlying conditions (infections, vascular trauma, immobilization, malignancies, autoimmune diseases, renal diseases, metabolic disorders, obesity, birth asphyxia, cardiac malformations, and use of prothrombotic drugs) with cerebral venous thrombosis (CVT) in children. Methods and Results-From 1995 to 2002, 149 pediatric patients aged newborn to Ͻ18 years (median 6 years) with CVT were consecutively enrolled. In patients and in 149 age-and gender-matched children with similar underlying clinical conditions but without CVT, the factor V G1691A mutation, the factor II G20210A variant, lipoprotein(a) [Lp(a)], protein C, protein S, antithrombin, and antiphospholipid antibodies, as well as associated clinical conditions, were investigated. Eighty-four (56.4%) of the patients had at least 1 prothrombotic risk factor compared with 31 control children (20.8%; PϽ0.0001). In addition, 105 (70.5%) of 149 patients with CVT presented with an underlying predisposing condition. On univariate analysis, factor V, protein C, protein S, and elevated Lp(a) were found to be significantly associated with CVT. However, in multivariate analysis, only the combination of a prothrombotic risk factor with an underlying condition (OR 3.9, 95% CI 1.8 to 8.6), increased Lp(a) (OR 4.1, 95% CI 2.0 to 8.7), and protein C deficiency (OR 11.1, 95% CI 1.2 to 104.4) had independent associations with CVT in the children investigated. Conclusions-CVT in children is

Lp(a) >30 mg/dL is a risk factor for venous thromboembolism in childhood. Lp(a) measurements should be included in the screening of causal factors in children with venous thromboembolic events.

Abstract-Plasma concentration of markers of inflammation are increased in patients with atherosclerosis.

Abstract-Risk factors for venous thrombosis in adults are the prothrombin G20210A and the factor V (FV) G1691A mutations and hereditary deficiencies of protein C, protein S and antithrombin. However, data are limited on the relevance of these risk factors for thrombosis in children and adolescents. We therefore investigated 261 patients aged 0 to 18 (median 5.7 years, 48% male) with venous thrombosis and controls (nϭ370) for the presence of prothrombotic risk factors including the prothrombin G20210A mutation. The following frequencies of hereditary risk factors (patients versus controls), odds ratios (OR) and 95% confidence intervals (CI), or results of Fisher's exact test, respectively, were