The interplay between macrophages and angiogenesis in development, tissue injury and regeneration

During organ development and remodeling, macrophages support angiogenesis, not only by secreting proangiogenic growth factors and matrix-remodeling proteases, but also by physically interacting with the sprouting vasculature to assist the formation of complex vascular networks. Recent data further indicate that embryonic and tumor-associated macrophages express similar genetic programs, possibly suggesting convergent functions in organogenesis and tumorigenesis. In this article, we review the role of macrophages in development, tissue injury and regeneration, by focusing on the mechanisms used by subsets of these cells, such as the TIE2-expressing macrophages, to regulate angiogenesis and lymphangiogenesis in both fetal and post-natal life

Aflatoxin M1 in Cow’s Milk: Method Validation for Milk Sampled in Northern Italy

Aflatoxins (AFs) are mycotoxins produced by some species of Aspergillus. In dairy cows, ingested AFB1 is metabolized into carcinogenic AFM1 which is eliminated through milk, thus posing a risk for consumer health. Here we describe the set, validation, and application of screening (ELISA) and confirmatory (HPLC) tests carried out on milk samples collected through official control of mycotoxin levels in northern Italy over a three-year period (2012–2014). The limit of detection (LOD) was set at 5 ppt (ng/kg) and 2 ppt for ELISA and HPLC, respectively, and the limit of quantification (LOQ) was 10 ppt for confirmatory HPLC. A total of 1668 milk samples were analyzed: ELISA identified 36 (2.2%) positive milk samples that were subsequently confirmed by HPLC. The level of AFM1 in the positive samples ranged between 18 ± 2 and 208 ± 27 ppt. Of the total samples, only eight (0.5%) were found non-compliant with the EU regulatory limit (50 ppt; range 74 ± 10 to 208 ± 27 ppt). Use of ELISA and HPLC tests in series allows for high-volume analysis of samples, thus saving time and money while guaranteeing high analytical precision and accuracy

27. Aberrant Expression of the Stem Cell microRNA-126 Induces B Cell Malignancy

MicroRNAs are essential regulators of normal and malignant hematopoiesis. miRNAs are relevant for gene therapy, since they can be exploited to fine-tune the expression profile of vector constructs or to alter viral tropism (GentnerN Chiriaco et al, 2014; Escobar et al, 2014) and described the function of miR-126 in HSC where it regulates the balance between quiescence and self-renewal (Lechman et al, 2012). We here report a novel role for miR-126 in the induction and maintenance of high-grade B cell malignancies. By ectopically expressing miR-126 in transplanted BM cells, we observed that up to 60% of mice (n=71) developed B cell malignancies. LV insertion site (IS) analysis revealed that all tumors were monoclonal. We then tracked back leukemic clone to different hematopoietic lineages prospectively purified from the mice 2-6 months before disease onset. IS sharing between normal lineages and leukemic clone suggests stem or multipotent progenitor cell as origin for most tumors. Importantly, we show that miR-126 is the direct cause of genesis and maintenance of leukemia, since leukemogenesis is abolished when miRNA expression is inhibited by doxycycline (doxy) using a tetracycline-repressible miR-126 cassette, and established symptomatic leukemia completely regresses when miR-126 is switched off by doxy through induction of apoptosis. Transcriptional profiling indicated that miR-126 regulates multiple genes in p53 pathway both in murine blasts and in normal human CD34+ cells. Previous work suggested expression of miR-126 in acute lymphoblastic leukemia (ALL) and germinal center lymphoma. To further establish the relevance of miR-126 in human disease, we measured miR-126 expression in blasts from 16 adult patients with ALL. miR-126 was highly expressed in most studied ALL cases (Phil+: n=11, Phil-: n=5), at similar levels as CD34+ cells. We then down-regulated miR-126 in primary blasts from human B-ALL patients (n=5), and we observed increased apoptosis and impaired engraftment in xenograft models after primary and secondary transplantation (miR-126/KD: n=32 mice; Ctrl: n=37 mice), demonstrating the relevance of miR-126 in human B-ALL. In conclusion, we present a novel spontaneous mouse model for high grade B cell malignancies which are addicted to miR-126 expression, provide insight into the dynamic process of leukemogenesis by clonal IS tracking and unveil key tumor signaling pathways controlled by miR-126. Down-regulation of miR-126 could be exploited as therapeutic strategy in ALL, since it would deplete leukemic cells while expanding normal HSC, two ways to restore normal hematopoieis

Small vessel disease and biomarkers of endothelial dysfunction after ischaemic stroke

Abstract Introduction: Although pathogenesis of small vessel disease is poorly understood, increasing evidence suggests that endothelial dysfunction may have a relevant role in development and progression of small vessel disease. In this crosssectional study, we investigated the associations between imaging signs of small vessel disease and blood biomarkers of endothelial dysfunction at two different time points in a population of ischaemic stroke patients. Patients and methods: In stroke patients treated with intravenous thrombolysis, we analysed blood levels of von Willebrand factor, intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and vascular endothelial growth factor. Three reviewers independently assessed small vessel disease features using computed tomography. At baseline and 90 days after the index stroke, we tested the associations between single and combined small vessel disease features and levels of blood biomarkers using linear regression analysis adjusting for age, sex, hypertension, diabetes, smoke. Results: A total of 263 patients were available for the analysis. Mean age (SD) was 69 (13) years, 154 (59%) patients were male.We did not find any relation between small vessel disease and endothelial dysfunction at baseline. At 90 days, leukoaraiosis was independently associated with intercellular adhesionmolecule-1 (b¼0.21; p¼0.016) and vascular cell adhesionmolecule- 1 (b¼0.22; p¼0.009), and lacunes were associated with vascular endothelial growth factor levels (b¼0.21; p¼0.009) whereas global small vessel disease burden was associated with vascular endothelial growth factor (b¼0.26; p¼0.006). Discussion: Leukoaraiosis and lacunes were associated with endothelial dysfunction, which could play a key role in pathogenesis of small vessel disease

miR-126 Regulates Distinct Self-Renewal Outcomes in Normal and Malignant Hematopoietic Stem Cells

SummaryTo investigate miRNA function in human acute myeloid leukemia (AML) stem cells (LSC), we generated a prognostic LSC-associated miRNA signature derived from functionally validated subpopulations of AML samples. For one signature miRNA, miR-126, high bioactivity aggregated all in vivo patient sample LSC activity into a single sorted population, tightly coupling miR-126 expression to LSC function. Through functional studies, miR-126 was found to restrain cell cycle progression, prevent differentiation, and increase self-renewal of primary LSC in vivo. Compared with prior results showing miR-126 regulation of normal hematopoietic stem cell (HSC) cycling, these functional stem effects are opposite between LSC and HSC. Combined transcriptome and proteome analysis demonstrates that miR-126 targets the PI3K/AKT/MTOR signaling pathway, preserving LSC quiescence and promoting chemotherapy resistance

Circulating endothelial progenitors and tumor resistance to vascular-targeting therapies

Acute mobilization of circulating endothelial progenitors has been implicated in tumor resistance to vascular-disrupting agents. In the current issue of Cancer Discovery, Taylor and colleagues provide novel insight into the kinetics of endothelial progenitor mobilization by vascular-disrupting agents in both mouse tumor models and cancer patients. Cancer Discov; 2(5); 395-7. ©2012 AACR

Implant Site Changes in Three Different Clinical Approaches: Orthodontic Extrusion, Regenerative Surgery and Spontaneous Healing after Extraction: A Systematic Review

Both surgical and non-surgical techniques are employed for implant site development. However, the efficacy of these methods has not been thoroughly evaluated and compared. This systematic review aims to compare the biologic, functional and esthetic outcomes of three different approaches before implant placement in both the maxillary and mandibular arches: orthodontic extrusion, regenerative surgery and spontaneous healing after extraction. The systematic research of articles was conducted up to January 2020 in Medline, Scopus and the Cochrane Library databases. Studies were selected in a three-stage process according to the title, the abstract and the inclusion criteria. The methodological quality and the risk of bias of the included studies were evaluated using ROBINS-I tools for non-randomized studies, Rob 2.0 for RCT. Quality evaluation of case reports was performed using CARE guidelines. Through the digital search, 1607 articles were identified, and 25 of them were included in the systematic review. The qualitative evaluation showed a good methodological quality for RCT, sufficient for non-randomized studies and poor for case reports. Based on the available results, both orthodontic extrusion and regenerative surgery allowed the development of the implant site with satisfying esthetic and functional outcomes. Studies about the spontaneous healing of the extraction socket showed resorption of the edentulous ridge, which complicated the implant insertion. No study referred to failures or severe complications. Most of the studies reported only qualitative results. The present systematic review demonstrated that there is a substantial lack of data and evidence to determine which of the presented methods is better for developing a future implant site. Both surgical and non-surgical procedures appear effective in the regeneration of hard tissue, whereas not all the techniques can improve soft tissue volume, too. The orthodontic technique simultaneously enhances both hard and soft tissue