Le genre en action: la catégorisation des locuteurs comme production située des participants dans l’interaction

<div><h3>Background</h3><p>Endogenous cardiac progenitor cells are a promising option for cell-therapy for myocardial infarction (MI). However, obtaining adequate numbers of cardiac progenitors after MI remains a challenge. Cardiospheres (CSs) have been proposed to have cardiac regenerative properties; however, their cellular composition and how they may be influenced by the tissue milieu remains unclear.</p> <h3>Methodology/Principal Finding</h3><p>Using “middle aged” mice as CSs donors, we found that acute MI induced a dramatic increase in the number of CSs in a mouse model of MI, and this increase was attenuated back to baseline over time. We also observed that CSs from post-MI hearts engrafted in ischemic myocardium induced angiogenesis and restored cardiac function. To determine the role of Sca-1⁺CD45^- cells within CSs, we cloned these from single cell isolates. Expression of Islet-1 (Isl1) in Sca-1⁺CD45^- cells from CSs was 3-fold higher than in whole CSs. Cloned Sca-1⁺CD45^- cells had the ability to differentiate into cardiomyocytes, endothelial cells and smooth muscle cells <em>in vitro</em>. We also observed that cloned cells engrafted in ischemic myocardium induced angiogenesis, differentiated into endothelial and smooth muscle cells and improved cardiac function in post-MI hearts.</p> <h3>Conclusions/Significance</h3><p>These studies demonstrate that cloned Sca-1⁺CD45^- cells derived from CSs from infarcted “middle aged” hearts are enriched for second heart field (i.e., Isl-1⁺) precursors that give rise to both myocardial and vascular tissues, and may be an appropriate source of progenitor cells for autologous cell-therapy post-MI.</p> </div

Cellular composition of CSs from mouse hearts.

<p>(A) Flow cytometric analysis of Sca-1, CD45 and c-kit expression in disaggregated CS cells. Typical results are shown (N = 6). (B, C) Bar graph showing the profile of progenitor cell markers in CSs by FACS (N = 6). (D) Immunocytochemical staining demonstrates that CS cells express Isl1, Nkx2-5 and GATA4. Arrows point to positive staining cells (red). Nuclei stained with DAPI. Scale bar = 35 µm and 15 µm (NKx2-5). (E) Bar graph shows the profile of Isl1, Nkx2-5, GATA4 positive cells in CSs by immunocytochemical staining. Data in Figure shown as mean±SEM.</p

CS cells engraft in ischemic myocardium.

<p>CS cells from 1-week post-MI GFP transgenic mice were injected into the peri-infarct zone (PZ) of syngeneic wild type mice 3 days post-MI. Injected cells were detected in the PZ at 25 days after delivery. The surviving cells expressed cardiac Troponin I (A), CD31 (B), and SMA (C). Nuclei were stained with DAPI. Typical results are shown (N = 7). Scale bars = 15 µm in A, B and C.</p

Myocardial injury increases the production of CSs.

<p>(A) Numbers of CS-forming cells harvested from hearts at 1-week and 2-weeks post-MI was significantly higher than those from sham-operated and non-operated hearts (N = 6). (B) Hearts at 1- and 2-weeks post-MI generated more CSs than sham-operated and non-operated hearts. # P<0.03. Hearts at 4-weeks post-MI produced similar number of CSs to sham-operated hearts (N = 6). Data in Figure shown as mean±SEM.</p

Cloned Sca-1⁺CD45⁻ cells differentiate into cardiac cells <i>in vitro</i>.

<p>(A–C) After treatment with 5-azacytidine, TGF-β and vitamin C, cloned Sca-1⁺CD45⁻ cells differentiated <i>in vitro</i> into cardiomyocytes expressing cardiac Troponin T (A), sarcomeric α-actinin⁺ (SA; B), and connexin-43 (C). (D–H) After treatment VEGF, the cloned cells differentiated into endothelial cells expressing CD31 (D), Von Willebrand Factor (VWF; F), and Flk1 (G), and smooth muscle cells expressing SMA (H). The endothelial cells also demonstrated acetylated LDL uptake (Dil-ac-LDL; E). Nuclei were stained with DAPI. Scale bar = 15 µm in A, D, E, Scale bar = 35 µm in B, C, F, G and H. Typical results are shown (N = 3).</p

Isl1⁺ cells are present in adult heart and CSs.

<p>Real-time RT-PCR was used to compare Isl1 expression in heart, indicated cells, and liver (negative control). Results show as Isl1 mRNA expression relative to Hypoxanthine phosphoribosyltransferase (HPRT). (A) Isl1 expression in CSs (N = 10) was 17-fold higher than in the hearts (n = 4). (B) Isl1 expression in Sca-1⁺CD45⁻ cells (N = 6) derived from CSs was 3-fold higher compared to that in whole CSs (N = 10). (C) Isl1 expression in cloned Sca-1⁺ CD45⁻ cells (n = 5) was similar to primary Sca-1⁺CD45⁻ cells isolated from CSs (N = 6). Isl1 expression dropped significantly with differentiation (N = 3). CM: cardiomyocytes.</p

Cellular composition of CSs from injured hearts.

<p>(A) The percentages of Sca-1⁺CD45⁻ in CSs were not altered by MI (N = 6). (B) The percentages of total CD45⁺cells in CSs was increased at 1-week post-MI and attenuated at 2-week post-MI (N = 6). (C) Semi-quantitative RT-PCR analysis showed that CSs from all groups expressed similar level of Nkx2-5, GATA4, Flk-1 and SMA. HPRT was used as control. N: Non-surgery. S: Sham-operated. 1W: 1 week post-MI. 2W: 2 weeks post-MI. 4W: 4 weeks post-MI. H: mouse heart (positive control). SM: skeletal muscle (negative control). Data in Figure shown as mean±SEM.</p

Analysis of cloned Sca-1⁺CD45^- cells.

<p>(A) Flow cytometry showed that ∼60% of cloned cells were Sca-1⁺CD45⁻. Typical results are shown (N = 6). (B–D) Immunocytochemical staining showed that cloned Sca-1⁺CD45⁻ cells expressed Isl-1 (B), Nkx2-5 (C) and GATA4 (D). Nuclei were stained with DAPI. Scale bar = 35 µm in B3; Scale bar = 15 µm in C3 and D3. Typical results are shown (N = 3).</p

Cloned Sca-1⁺CD45⁻ cells differentiate into endothelial and smooth muscle cells <i>in vivo</i>.

<p>Cloned Sca-1⁺CD45⁻GFP⁺ cells were injected into the peri-infarct zone (PZ) of infarcted myocardium of syngeneic wild type mice 3 days post-MI. Injected cells were detected by GFP expression 25 days after transplantation, but there was no evidence of cardiac differentiation at this time point (A) (N = 7). At 75 days post-injection (C–D), transplanted cells were detected in the PZ, and expressed CD31 (C) and SMA (D), but not Troponin I (B). Nuclei were stained with DAPI. Scale bar = 35 µm in A, B, C and D. Typical results are shown (N = 2).</p

sj-docx-1-eso-10.1177_23969873231223307 – Supplemental material for Bushfire-smoke trigger hospital admissions with cerebrovascular diseases: Evidence from 2019–20 bushfire in Australia

Supplemental material, sj-docx-1-eso-10.1177_23969873231223307 for Bushfire-smoke trigger hospital admissions with cerebrovascular diseases: Evidence from 2019–20 bushfire in Australia by Md Golam Hasnain, Carlos Garcia-Esperon, Yumi Kashida Tomari, Rhonda Walker, Tarunpreet Saluja, Md Mijanur Rahman, Andrew Boyle, Christopher R Levi, Ravi Naidu, Gabriel Filippelli and Neil J Spratt in European Stroke Journal</p