Multinomial logistic regression comparing those who did versus those who did not intend to vaccinate (N = 351).

Multinomial logistic regression comparing those who did versus those who did not intend to vaccinate (N = 351).</p

Zebrafish as a model to investigate a biallelic gain-of-function variant in MSGN1, associated with a novel skeletal dysplasia syndrome

Abstract Background/Objectives Rare genetic disorders causing specific congenital developmental abnormalities often manifest in single families. Investigation of disease-causing molecular features are most times lacking, although these investigations may open novel therapeutic options for patients. In this study, we aimed to identify the genetic cause in an Iranian patient with severe skeletal dysplasia and to model its molecular function in zebrafish embryos. Results The proband displays short stature and multiple skeletal abnormalities, including mesomelic dysplasia of the arms with complete humero-radio-ulna synostosis, arched clavicles, pelvic dysplasia, short and thin fibulae, proportionally short vertebrae, hyperlordosis and mild kyphosis. Exome sequencing of the patient revealed a novel homozygous c.374G > T, p.(Arg125Leu) missense variant in MSGN1 (NM_001105569). MSGN1, a basic-Helix–Loop–Helix transcription factor, plays a crucial role in formation of presomitic mesoderm progenitor cells/mesodermal stem cells during early developmental processes in vertebrates. Initial in vitro experiments show protein stability and correct intracellular localization of the novel variant in the nucleus and imply retained transcription factor function. To test the pathogenicity of the detected variant, we overexpressed wild-type and mutant msgn1 mRNA in zebrafish embryos and analyzed tbxta (T/brachyury/ntl). Overexpression of wild-type or mutant msgn1 mRNA significantly reduces tbxta expression in the tailbud compared to control embryos. Mutant msgn1 mRNA injected embryos depict a more severe effect, implying a gain-of-function mechanism. In vivo analysis on embryonic development was performed by clonal msgn1 overexpression in zebrafish embryos further demonstrated altered cell compartments in the presomitic mesoderm, notochord and pectoral fin buds. Detection of ectopic tbx6 and bmp2 expression in these embryos hint to affected downstream signals due to Msgn1 gain-of-function. Conclusion In contrast to loss-of-function effects described in animal knockdown models, gain-of-function of MSGN1 explains the only mildly affected axial skeleton of the proband and rather normal vertebrae. In this context we observed notochord bending and potentially disruption of pectoral fin buds/upper extremity after overexpression of msgn1 in zebrafish embryos. The latter might result from Msgn1 function on mesenchymal stem cells or on chondrogenesis in these regions. In addition, we detected ectopic tbx6 and bmp2a expression after gain of Msgn1 function in zebrafish, which are interconnected to short stature, congenital scoliosis, limb shortening and prominent skeletal malformations in patients. Our findings highlight a rare, so far undescribed skeletal dysplasia syndrome associated with a gain-of-function mutation in MSGN1 and hint to its molecular downstream effectors

Abstract Number ‐ 49: Risk of HT with Early DOACs after Acute Ischemic Stroke: A Pooled Analysis

Introduction The risk of hemorrhagic transformation (HT) in the early phase of acute ischemic stroke (AIS) remains unknown, leading to potential unnecessary delays in initiation of anticoagulation for secondary stroke prevention. We sought to assess the rate of HT associated withdirect oral anticoagulant (DOAC) initiation within and beyond 48 hours after AIS, using a pooled analysis of available published data. Methods A pooled analysis of 6 studies (4 prospective observational blinded outcome studies and2 randomized trials) of DOAC initiation within 14 days of AIS or transient ischemic attack (TIA) was conducted. The primary endpoint was incident radiographic HT on follow‐up imaging. Secondary endpoints included symptomatic HT, new parenchymal hemorrhage, recurrent ischemic events, extracranial hemorrhage, mortality within the study period, and follow‐up modified Rankin Scale score.The results were reported as odds ratio (OR) andhazard ratio (HR)with 95% confidence interval (CI). Results We evaluated 509 patients; median infarct volume was1.5 (0.1‐7.8) ml, andmedian National Institutes of Health Stroke Scale was2 (0‐3).Incident radiographic HT was seen on follow‐up scan in 34 (6.8%) patients.DOAC initiation within 48 hours from index event was not associated with incident HT (adjusted OR 0.67, [0.30 – 1.50]P = 0.32).No patients developed symptomatic HT.Conversely, 31 (6.1%) patients developedrecurrent ischemic events, 64% of which occurred within 14 days.Initiating a DOAC within 48 hours of onset was associated with a trend towards lower rates of recurrent ischemic events, but this was not statistically significant (HR 0.42, [0.17 – 1.008]P = 0.052). In contrast to HT,recurrent ischemic events were associated with poor functional outcomes (OR = 6.8, [2.84 – 16.24], p< 0.001). Conclusions Initiation of DOAC within 48 hours after stroke was not associated with decreased risk of recurrent ischemic events, or increasedincident risk of HT. Both recurrent ischemic events and incident HT occurred at similar rates.Unlike HT, however, recurrent ischemic events were associated with poor outcomes

Very late antigen-4 function of myeloblasts correlates with improved overall survival for patients with acute myeloid leukemia

Adhesion of acute myeloid leukemia (AML) blasts in the bone marrow microenvironment confers protection from chemotherapy-induced apoptosis. One mechanism for retention of blasts within the bone marrow is adhesion via very late antigen-4 (VLA-4), the α4β1 integrin heterodimer that binds to its main ligands, fibronectin, and vascular cell adhesion molecule-1 (VCAM-1). To examine the relationship of functional expression of VLA-4 to prognosis in AML, we studied marrow samples from 175 adult AML patients who underwent induction chemotherapy with anthracycline and cytarabine on Southwest Oncology Group trials. The studies included flow cytometry and functional in vitro assays for ligand binding and maximal β1 activation. VLA-4 expression varied widely, with mean expression 60.6% for α4, and was not significantly associated with response to chemotherapy, relapse-free, or overall survival (OS). However, increased binding of soluble VCAM-1 via VLA-4 was significantly associated with longer OS, corrected for age (P = .033). Estimated 5-year OS was 31% (95% confidence interval, 14%-48%) in 30 patients with soluble VCAM-1 binding greater than or equal to 40%, compared with 10% (confidence interval, 3%-17%) in 72 patients with lower binding. Adhesion and migratory properties of AML blasts thus appear to influence chemosensitivity and therefore may be therapeutic targets