Overview of the marine litter status in the Atlantic Area: floating litter

CleanAtlantic is an INTERREG Atlantic Area Programme project that aimed at protecting biodiversity and ecosystem services in the Atlantic Area by improving capabilities to monitor, prevent and remove (macro) marine litter. Besides, the project also contributed to raise awareness and change attitudes among stakeholders and to improve marine litter managing systems. To achieve these aims, the work was organised in 8 work packages. The present deliverable aims at synthesizing the main results achieved on the frame of the action 1 of work package 4, which focused on the Regional characterisation of marine litter in the Atlantic Area. More specifically, this report deals with the assessment of the floating litter data available in this area. Additionally, the major key findings, gaps on monitoring and research as well as potential improvements and recommendations are identified

Overview of the marine litter status in the Atlantic Area: beach, floating and seabed litter

CleanAtlantic is an INTERREG Atlantic Area Programme project that aimed at protecting biodiversity and ecosystem services in the Atlantic Area by improving capabilities to monitor, prevent and remove (macro) marine litter. Besides, the project also contributed to raise awareness and change attitudes among stakeholders and to improve marine litter managing systems. To achieve these aims, the work was organised in 8 work packages. The present deliverable aims at synthesizing the main results obtained on the frame of the action 1 of work package 4, which focused on the Regional characterisation of marine litter in the Atlantic Area. With this purpose, an overview of marine litter status in beach, floating and seabed compartments in the Atlantic Area is presented. Additionally, the major key findings, gaps on monitoring and research as well as potential improvements and recommendations are identified. Links to the complete dedicated reports for each compartment are included in the references section. Also, an interactive map for spatial visualization of data on beach, floating and seabed litter composition and abundance in the Atlantic Area was created and is presented at the end of this report

Characterization of floating microplastic contamination in the bay of Marseille (French Mediterranean Sea) and its impact on zooplankton and mussels

Microplastics (MPs) were sampled in three seasons from 2016 to 2018 in the Bay of Marseille, northwestern Mediterranean Sea, adjacent to a highly urbanized area. Six sites were selected according to their different characteristics (river mouth, treatment plants, protected marine area). Surface floating MPs were characterized (number, weight, typology and polymer) as was zooplankton. In addition, mussels were submerged and used to investigate ingestion. Finally, a hydrodynamic model was used to improve understanding of dispersion mechanisms. The annual averages of floating MPs values ranged from 39,217 to 514,817 items/km2. The MPs collected were mainly fragments principally composed of polyethylene and polypropylene. The mean abundance ratio (MPs/zooplankton) was 0.09. On average 87% of mussel pools were contaminated and ingested 18.73 items/100 g of flesh. Two hydrodynamic patterns were identified: the first retaining the MPs in the harbor, and the second dispersing them outside

Smooth Muscle-Like Cells Generated from Human Mesenchymal Stromal Cells Display Marker Gene Expression and Electrophysiological Competence Comparable to Bladder Smooth Muscle Cells

The use of mesenchymal stromal cells (MSCs) differentiated toward a smooth muscle cell (SMC) phenotype may provide an alternative for investigators interested in regenerating urinary tract organs such as the bladder where autologous smooth muscle cells cannot be used or are unavailable. In this study we measured the effects of good manufacturing practice (GMP)-compliant expansion followed by myogenic differentiation of human MSCs on the expression of a range of contractile (from early to late) myogenic markers in relation to the electrophysiological parameters to assess the functional role of the differentiated MSCs and found that differentiation of MSCs associated with electrophysiological competence comparable to bladder SMCs. Within 1-2 weeks of myogenic differentiation, differentiating MSCs significantly expressed alpha smooth muscle actin (αSMA; ACTA2), transgelin (TAGLN), calponin (CNN1), and smooth muscle myosin heavy chain (SM-MHC; MYH11) according to qRT-PCR and/or immunofluorescence and Western blot. Voltage-gated Na+ current levels also increased within the same time period following myogenic differentiation. In contrast to undifferentiated MSCs, differentiated MSCs and bladder SMCs exhibited elevated cytosolic Ca2+ transients in response to K+-induced depolarization and contracted in response to K+ indicating functional maturation of differentiated MSCs. Depolarization was suppressed by Cd2+, an inhibitor of voltage-gated Ca2+-channels. The expression of Na+-channels was pharmacologically identified as the Nav1.4 subtype, while the K+ and Ca2+ ion channels were identified by gene expression of KCNMA1, CACNA1C and CACNA1H which encode for the large conductance Ca2+-activated K+ channel BKCa channels, Cav1.2 L-type Ca2+ channels and Cav3.2 T-type Ca2+ channels, respectively. This protocol may be used to differentiate adult MSCs into smooth muscle-like cells with an intermediate-to-late SMC contractile phenotype exhibiting voltage-gated ion channel activity comparable to bladder SMCs which may be important for urological regenerative medicine applications

Levels of voltage-activated Na⁺ currents and Na⁺ channels.

<p>(A) Voltage-activated Na⁺ currents were elicited by a voltage step from -120 mV to +20 mV. MSCs: trace from undifferentiated MSCs in control medium (undiff MSC-FBS) and GMP expansion medium (MSC-GMP); d7: trace from MSCs after 7 days in myogenic differentiation medium; SMC: trace from primary bladder SMCs. Capacitive transient is blanked for better visualization. (B) Na⁺ current density for undifferentiated MSCs in control medium (MSC FBS) and GMP medium (MSC GMP), as well as MSCs differentiated for 7, 14 or 21 days and SMCs, respectively. <i>n</i> = 10–20. * p<0.05. Error bars indicate SEM. (C) Effect of TTX on Na⁺ currents in undifferentiated MSCs (here: MSC in control medium). Superposition of Na⁺ currents elicited at +20mV. Na⁺ channels could be blocked by the specific Na⁺ channel inhibitor TTX. (D) Effect of TTX on Na⁺ currents in MSCs that were differentiated for 7 days. Superposition of Na⁺ currents elicited at +20mV. TTX blocks the current concentration-dependently.</p

Levels of intracellular Ca²⁺.

<p>Ca²⁺ imaging of (A) bladder SMCs and (B) differentiated MSCs (d7). K⁺-induced depolarization increased the intracellular Ca²⁺ content (black trace). Depolarization in the presence of 50 μM Cd²⁺ prevented the Ca²⁺ increase (dashed trace). (C) In undifferentiated MSCs (expanded in GMP expansion medium) no transient increase in cytosolic Ca²⁺ was observed in response to K+ induced depolarization. Arrow indicates time point in which 15 mM K⁺ was added to the bath solution.</p

Blockage of voltage-gated Na⁺ channel subtypes.

<p>(A) Application of 100nM ranolazine reduced the peak amplitude of voltage-activated Na⁺ channels [(<i>n</i> = 3 for undifferentiated MSCs (cultured in GMP expansion medium), <i>n</i> = 4 for SMCs, <i>n</i> = 5 for MSCs that were differentiated for 5–10 days and <i>n</i> = 7 for MSCs differentiated for 13–21 days (Diff MSC)] compared to the respective control (= 1.0, not shown). (B) Application of pro-toxin II inhibited voltage-gated Na⁺ channels in SMCs. Superposition of single current traces obtained in control (bold), at 2nM (dashed) and 100nM (dotted) from one donor, respectively. (C) Summary plot of current inhibition by pro-toxin II. Data obtained from n = 4 experiments. * p<0.05. Error bars indicate SEM.</p

Expression of contractile SMC-specific proteins analyzed by immunofluorescence.

<p>MSCs were expanded in GMP expansion medium until they were 70% confluent and at passage 2 treated with control medium or SMC differentiation medium for 14 days, fixed and then analyzed by immunofluorescence for expression of αSMA, transgelin, calponin and SM-MHC. Primary human bladder smooth muscle cells (HBdSMC) served as the positive control. Nuclei were stained with DAPI. Magnification 20x. Representative of <i>n</i> = 3.</p