Citations

Context: Research examining the source of excess soluble fms-like tyrosine kinase 1 (sFLT1) in preeclampsia has focused on the placenta. The potential contribution of the releasable store of sFLT1 in the systemic vasculature is unknown. Objective: We asked whether the nonplacental releasable store of sFLT1 is larger in women with previous preeclampsia than in women with a previous uncomplicated pregnancy. Design: We administered heparin to nulligravid women and to women with previous preeclampsia or a previous uncomplicated pregnancy. We compared post-heparin sFLT1 concentrations with those observed in uncomplicated pregnancy and preeclampsia. Setting: The study was performed at Magee-Womens Hospital. Patients: Participants included nulligravidas (n = 8), women 6–24 months postpartum (previous uncomplicated pregnancy, n = 16; previous preeclampsia, n = 15), and pregnant women (uncomplicated pregnancy, n = 30; preeclampsia, n = 25). Intervention: Nonpregnant women received an unfractionated heparin bolus. Main Outcome Measures: Pre- and post-heparin plasma sFLT1, placental growth factor, and vascular endothelial growth factor were measured. Results: In nonpregnant women, heparin increased plasma sFLT1 by 250-fold (P < .01), increased placental growth factor by 7-fold (P < .01), and decreased free vascular endothelial growth factor (P < .01). These changes did not differ between nulligravidas, women with previous preeclampsia, and women with a previous uncomplicated pregnancy. Post-heparin sFLT1 in nonpregnant women was higher than sFLT1 in uncomplicated pregnancy, but lower than sFLT1 in preeclampsia. Baseline and post-heparin sFLT1 were positively correlated (r2 = 0.19; P < .01). Heparin increased the concentration of the 100-kDa sFLT1 isoform. Adding heparin to whole blood or plasma did not increase sFLT1. Conclusions: Nonpregnant women have a significant vascular store of releasable sFLT1. The size of this store does not differ between women with previous preeclampsia vs women with previous uncomplicated pregnancy.

Directional mesenchymal cell invasion in vivo is understood to be a stimulated event and to be regulated by cytokines, chemokines, and types of extracellular matrix (ECM). Instead, by focusing on the cellular response to ECM stiffness, we found that soft ECM (low stiffness) itself is sufficient to prevent stable cell-to-cell adherens junction formation, up-regulate matrix metalloproteinase (MMP) secretion, promote MMP activity, and induce invadosome-like protrusion (ILP) formation. Consistently, similar ILP formation was also detected in a three-dimensional directional invasion assay in soft matrix. Primary human fibroblasts spontaneously form ILPs in a very narrow range of ECM stiffness (0.1–0.4 kPa), and such ILP formation is Src family kinase dependent. In contrast, spontaneous ILP formation in malignant cancer cells and fibrosarcoma cells occurs across a much wider range of ECM stiffness, and these tumor cell ILPs are also more prominent at lower stiffness. These findings suggest that ECM softness is a natural stimulator for cellular invasiveness.

Key Points STAT5 is constitutively phosphorylated in malignant B cells obtained from patients with Waldenström's macroglobulinemia. Inhibition of STAT5 signaling significantly decreases IgM production and may be useful therapeutically for patients with high IgM levels.

ABSTRACT Measles virus (MV) immunosuppression is due to infection of SLAM-positive immune cells, whereas respiratory shedding and virus transmission are due to infection of nectin4-positive airway epithelial cells. The vaccine lineage MV strain Edmonston (MV-Edm) acquired an additional tropism for CD46 which is the basis of its oncolytic specificity. VSVFH is a vesicular stomatitis virus (VSV) encoding the MV-Edm F and H entry proteins in place of G. The virus spreads faster than MV-Edm and is highly fusogenic and a potent oncolytic. To determine whether ablating nectin4 tropism from VSVFH might prevent shedding, increasing its safety profile as an oncolytic, or might have any effect on CD46 binding, we generated VSVFH viruses with H mutations that disrupt attachment to SLAM and/or nectin4. Disruption of nectin4 binding reduced release of VSVFH from the basolateral side of differentiated airway epithelia composed of Calu-3 cells. However, because nectin4 and CD46 have substantially overlapping receptor binding surfaces on H, disruption of nectin4 binding compromised CD46 binding and greatly diminished the oncolytic potency of these viruses on human cancer cells. Thus, our results support continued preclinical development of VSVFH without ablation of nectin4 binding.

Objective The objective of this article is to evaluate electrically evoked thresholds for cortical spreading depression (CSD) and stress-induced activation of trigeminal afferents in a rat model of medication-overuse headache (MOH). Methods Sumatriptan or saline was delivered subcutaneously by osmotic minipump for six days to Sprague-Dawley rats. Two weeks after pump removal, animals were anesthetized and recording/stimulating electrodes implanted. The animals were pretreated with vehicle or topiramate followed by graded electrical stimulation within the visual cortex. CSD events were identified by decreased EEG amplitude and DC potential shift. Additional unanesthetized sumatriptan or saline-pretreated rats were exposed to bright light environmental stress and periorbital and hindpaw withdrawal thresholds were measured. Following CSD stimulation or environmental stress, immunohistochemical staining for Fos in the trigeminal nucleus caudalis (TNC) was performed. Results Sumatriptan pre-exposure significantly decreased electrical stimulation threshold to generate a CSD event. Topiramate normalized the decreased CSD threshold as well as stress-induced behavioral withdrawal thresholds in sumatriptan-treated rats compared to saline-treated animals. Moreover, CSD and environmental stress increased Fos expression in the TNC of sumatriptan-treated rats, and these effects were blocked by topiramate. Environmental stress did not elicit cutaneous allodynia or elevate TNC Fos expression in saline-treated rats. Conclusions A previous period of sumatriptan exposure produced long-lasting increased susceptibility to evoked CSD and environmental stress-induced activation of the TNC that was prevented by topiramate. Lowered CSD threshold, and enhanced consequences of CSD events (increased activation of TNC), may represent an underlying biological mechanism of MOH related to triptans.