Lipoprotein-associated phospholipase A2 (Lp-PLA2) as a therapeutic target to prevent retinal vasopermeability during diabetes

<p>Lipoprotein-associated phospholipase A2 (Lp-PLA2) hydrolyses oxidized low-density lipoproteins into proinflammatory products, which can have detrimental effects on vascular function. As a specific inhibitor of Lp-PLA2, darapladib has been shown to be protective against atherogenesis and vascular leakage in diabetic and hypercholesterolemic animal models. This study has investigated whether Lp-PLA2 and its major enzymatic product, lysophosphatidylcholine (LPC), are involved in blood-retinal barrier (BRB) damage during diabetic retinopathy. We assessed BRB protection in diabetic rats through use of species-specific analogs of darapladib. Systemic Lp-PLA2 inhibition using SB-435495 at 10 mg/kg (i.p.) effectively suppressed BRB breakdown in streptozotocin-diabetic Brown Norway rats. This inhibitory effect was comparable to intravitreal VEGF neutralization, and the protection against BRB dysfunction was additive when both targets were inhibited simultaneously. Mechanistic studies in primary brain and retinal microvascular endothelial cells, as well as occluded rat pial microvessels, showed that luminal but not abluminal LPC potently induced permeability, and that this required signaling by the VEGF receptor 2 (VEGFR2). Taken together, this study demonstrates that Lp-PLA2 inhibition can effectively prevent diabetes-mediated BRB dysfunction and that LPC impacts on the retinal vascular endothelium to induce vasopermeability via VEGFR2. Thus, Lp-PLA2 may be a useful therapeutic target for patients with diabetic macular edema (DME), perhaps in combination with currently administered anti-VEGF agents.</p>

Biallelic ATM inactivation significantly reduces survival in patients treated on the United Kingdom Leukemia Research Fund Chronic Lymphocytic Leukemia 4 trial.

PURPOSE: The prognostic significance of ATM mutations in chronic lymphocytic leukemia (CLL) is unclear. We assessed their impact in the context of a prospective randomized trial. PATIENTS AND METHODS: We analyzed the ATM gene in 224 patients treated on the Leukemia Research Fund Chronic Lymphocytic Leukemia 4 (LRF-CLL4) trial with chlorambucil or fludarabine with and without cyclophosphamide. ATM status was analyzed by denaturing high-performance liquid chromatography and was related to treatment response, survival, and the impact of TP53 alterations for the same patient cohort. RESULTS: We identified 36 ATM mutations in 33 tumors, 16 with and 17 without 11q deletion. Mutations were associated with advanced disease stage and involvement of multiple lymphoid sites. Patients with both ATM mutation and 11q deletion showed significantly reduced progression-free survival (median, 7.4 months) compared with those with ATM wild type (28.6 months), 11q deletion alone (17.1 months), or ATM mutation alone (30.8 months), but survival was similar to that in patients with monoallelic (6.7 months) or biallelic (3.4 months) TP53 alterations. This effect was independent of treatment, immunoglobulin heavy chain variable gene (IGHV) status, age, sex, or disease stage. Overall survival for patients with biallelic ATM alterations was also significantly reduced compared with those with ATM wild type or ATM mutation alone (median, 42.2 v 85.5 v 77.6 months, respectively). CONCLUSION: The combination of 11q deletion and ATM mutation in CLL is associated with significantly shorter progression-free and overall survival following first-line treatment with alkylating agents and purine analogs. Assessment of ATM mutation status in patients with 11q deletion may influence the choice of subsequent therapy.

Lead: Inorganic Chemistry

The article covers basic inorganic chemistry of lead. As an introduction, the properties and historical uses of metallic lead are discussed, followed by aspects of lead toxicity, including the toxicity origins and effects of lead poisoning. Properties of lead as a heavy p-block element are discussed, with emphasis on the modern view of the so-called ���inert pair effect���, including its origin, the influence on stability of lead oxidation states, and on the coordination chemistry of lead(II), viz., ���sterically active lone pair���. This is followed by an overview of lead inorganic compounds, including halides, pseudohalides, oxides and chalcogenides, hydroxides and their chalcogenide analogs, alkoxides, oxoacids, O-donors, S- and Se-donors, Group 15 donors, compounds with lead-transition metal bonds, and finally metallic clusters (Zintl phases). This is by no means a comprehensive review, rather compounds representative for each class were presented. In most sections, structural aspects of each class of compounds are discussed, followed by applications, with the focus on modern uses in material science.