Search

Children with Down syndrome (DS) bear an increased risk of acute lymphoblastic leukemia (ALL) and treatment complications. We compared blood counts and toxicities in 22 DS and 44 non-DS ALL patients. Patients with DS had deeper, longer neutrophil and monocyte count nadirs; more toxicities (HR 2.0, p = 0.0005); longer hospitalizations (HR 1.4, p < 0.0001); and more frequent microbiologically documented infections (HR 5.7, p = 0.0019), mucositis (HR 29.0, p = 0.0006), and cellulitis (HR 3.0, p= 0.033). Severe neutropenia, monocytopenia and increased cellulitis in DS-ALL suggest the importance of skin hygiene, vigilance and aggressive treatment of cutaneous infections.

Plasma ADAMTS13 deficiency results in the clinical disorder thrombotic thrombocytopenic purpura. However, other potential pathophysiological roles of ADAMTS13 in endothelial cell biology remain unexplored. To assess the possible role of ADAMTS13 and its interactions with VEGF-mediated angiogenesis, the effects of ADAMTS13 on human umbilical vein endothelial cell (HUVEC) were studied in Matrigel tube formation, proliferation, cell migration, and scratch wound assays. Treatment of endothelial cells with exogenous recombinant full-length ADAMTS13 alone promoted angiogenesis in a dose-dependent manner. HUVEC incubated with 200 ng/mL ADAMTS13 (1.4 nM) resulted in a 65% increase in cell tube formation when compared to the EBM-2 control. HUVEC treated with 30 ng/mL ADAMTS13 (204.1 pM) resulted in an 83% increase in proliferation in a visual counting assay, whereas HUVEC treated with 10 ng/mL ADAMTS13 (68.0 pM) yielded a 295% increase in EC migration in a Boyden chamber assay. In contrast, ADAMTS13 inhibited VEGF-induced angiogenesis in a dose-dependent manner, with 200ng/mL inhibiting tube formation by 35%. HUVEC co-incubated with ADAMTS13 and an antibody to the ADAMTS13 thrombospondin domains 5-7 reversed the inhibition of tube formation. HUVEC treated with 30 ng/mL ADAMTS13 and 6.2 ng/mL (323.0 pM) VEGF proliferated 40% slower than the VEGF control after 24 h of incubation as measured by visual counting assay. Treatment of HUVEC with 6.2 ng/mL VEGF and 10 ng/mL ADAMTS13 inhibited cell migration by 48%, compared to the VEGF control. Substitution of ADAMTS13 with truncated ADAMTS13 (deletion of C-terminal TSP1 domain) did not significantly increase angiogenesis or suppress VEGF-induced angiogenesis, suggesting that the TSP1 domain is involved in ADAMTS13 angiogenic activities. Co-immunoprecipitation experiments provided further evidence that ADAMTS13 binds to VEGF via its TSP1 domain.

Underwater passive acoustic directional sensors and Seaweb through-water networked acoustic communications are implemented in the Intracoastal Waterway at Morehead City, North Carolina on the U.S. eastern seaboard. The objective is to demonstrate capability for first-alert protection of a high-value port facility against asymmetric threats that intelligence sources indicate are arriving via watercraft. Battery-powered acoustic sensors are rapidly deployed at widely separated chokepoint locations in shallow 5–10 meter water. These sensors autonomously detect the passage of a maritime vessel and generate a contact report indicating time, location and heading of the target. Seaweb through-water acoustic communications delivers the contact report via a scalable wide-area underwater network including multiple acoustic repeater nodes and a radio/acoustic communications (Racom) gateway buoy. The Racom gateway telemeters the contact report via Iridium satellite communications to an ashore command center with low latency. The in situ acoustic detection is corroborated using shore-based video surveillance to classify the contact as friendly or actionable.

The molecular mechanism(s) responsible for channeling long-chain fatty acids (LCFAs) into oxidative versus nonoxidative pathways is (are) poorly understood in the heart. Intracellular LCFAs are converted to long-chain fatty acyl-CoAs (LCFA-CoAs) by a family of long-chain acyl-CoA synthetases (ACSLs). Cytosolic thioesterase 1 (CTE1) hydrolyzes cytosolic LCFA-CoAs to LCFAs, generating a potential futile cycle at the expense of ATP utilization. We hypothesized that ACSL isoforms and CTE1 are differentially regulated in the heart during physiological and pathophysiological conditions. Using quantitative RT-PCR, we report that the five known acsl isoforms (acsl1, acsl3, acsl4, acsl5, and acsl6) and cte1 are expressed in whole rat and mouse hearts, as well as adult rat cardiomyocytes (ARCs). Streptozotocin-induced insulin-dependent diabetes (4 wk) and fasting (/=24 h) both dramatically induced cte1 and repressed acsl6 mRNA, with no significant effects on the other acsl isoforms. In contrast, high-fat feeding (4 wk) induced cte1 without affecting expression of the acsl isoforms in the heart. Investigation into the mechanism(s) responsible for these transcriptional changes uncovered roles for peroxisome proliferator-activated receptor-alpha (PPARalpha) and insulin as regulators of specific acsl isoforms and cte1 in the heart. Culturing ARCs with oleate (0.1-0.4 mM) or the PPARalpha agonists WY-14643 (1 muM) and fenofibrate (10 muM) consistently induced acsl1 and cte1. Conversely, PPARalpha null mouse hearts exhibited decreased acsl1 and cte1 expression. Culturing ARCs with insulin (10 nM) induced acsl6, whereas specific loss of insulin signaling within the heart (cardiac-specific insulin receptor knockout mice) caused decreased acsl6 expression. Our data expose differential regulation of acsl isoforms and cte1 in the heart, where acsl1 and cte1 are PPARalpha-regulated genes, whereas acsl6 is an insulin-regulated gene.

Abstract 4307 The von Willebrand factor-cleaving protease, also known as ADAMTS13, is synthesized, in part, by endothelial cells (EC). We previously reported that proliferating EC secreted ∼3-fold more ADAMTS13 (antigen and activity) than confluent EC, and that this synthesis was transcriptionally regulated (SJ Kling et al, Pathophysiol Haemost Thromb 2008; 36: 233.) Thrombospondin domains, a defining feature of the ADAMTS protease family, in other ADAMTS family members mediate inhibition of angiogenesis. In particular, ADAMTS1 inhibits angiogenesis by sequestering vascular endothelial growth factor (VEGF) (A Luque et al, J Biol Chem, 2003; 278: 23656). Since ADAMTS13 also has thrombospondin domains, we hypothesized that ADAMTS13 might also mediate anti-angiogenic activity. Human umbilical vein EC angiogenesis was quantified by Angioquant analysis of fluorescence microscopy tube images in a Matrigel assay. Treatment of EC with inhibitors of angiogenesis (anti-VEGF, vasostatin) did not alter EC production of ADAMTS13. However, exogenous recombinant ADAMTS13 inhibited angiogenesis in a dose-dependent manner (Figure 1), in media containing VEGF. In VEGF-free media, ADAMTS13 had no effect on EC tube formation. Preincubation of ADAMTS13 with an antibody to the ADAMTS13 thrombospondin domains 5–7 partially reversed the inhibition of tube formation, implicating these domains in the anti-angiogenic interaction (Figure 2). We also found that VEGF co-immunoprecipitates with ADAMTS13, providing strong evidence that these two proteins interact. When EC lysates were crosslinked with DTSSP prior to immunoprecipitation, anti-ADAMTS13 immunoprecipitated as much VEGF as did anti-ADAMTS1, while an antibody to ADAM17, a similar protein that lacks thrombospondin domains, failed to co-immunoprecipitate VEGF (Figure 3). These data indicate that as with other ADAMTS family members, ADAMTS13 inhibits tubule formation - a parameter of angiogenesis – through its interaction with VEGF, an effect likely mediated by its thrombospondin domains. Inhibition of angiogenesis adds to the expanding roles of ADAMTS13 in down-regulation of thrombosis and inflammation. Fig. 1. Fig. 1. Fig. 2. Fig. 2. Fig. 3. An antibody to ADAMTS13 immunoprecipitates VEGF in similar amounts as anti-ADAMTS1 when proteins from HUVEC lysates are crosslinked prior to co-immunoprecipitation. Nonspecific IgG fails to immunoprecipitate VEGF, as does anti-ADAM17. (A1 = ADAMTS1; A13 = ADAMTS13) Fig. 3. An antibody to ADAMTS13 immunoprecipitates VEGF in similar amounts as anti-ADAMTS1 when proteins from HUVEC lysates are crosslinked prior to co-immunoprecipitation. Nonspecific IgG fails to immunoprecipitate VEGF, as does anti-ADAM17. (A1 = ADAMTS1; A13 = ADAMTS13) Disclosures: Fryer: American Diagnostica Inc: Employment. Greenfield:American Diagnostica Inc: Employment.