Pulmonary endothelial permeability and tissue fluid balance depend on the viscosity of the perfusion solution

Fluid filtration in the pulmonary microcirculation depends on the hydrostatic and oncotic pressure gradients across the endothelium and the selective permeability of the endothelial barrier. Maintaining normal fluid balance depends both on specific properties of the endothelium and of the perfusing blood. Although some of the essential properties of blood needed to prevent excessive fluid leak have been identified and characterized, our understanding of these remains incomplete. The role of perfusate viscosity in maintaining normal fluid exchange has not previously been examined. We prepared a high-viscosity perfusion solution (HVS) with a relative viscosity of 2.5, i.e., within the range displayed by blood flowing in vessels of different diameters in vivo (1.5–4.0). Perfusion of isolated murine lungs with HVS significantly reduced the rate of edema formation compared with perfusion with a standard solution (SS), which had a lower viscosity similar to plasma (relative viscosity 1.5). HVS did not alter capillary filtration pressure. Increased endothelial shear stress produced by increasing flow rates of SS, to mimic the increased shear stress produced by HVS, did not reduce edema formation. HVS significantly reduced extravasation of Evans bluelabeled albumin compared with SS, indicating that it attenuated endothelial leak. These findings demonstrate for the first time that the viscosity of the solution perfusing the pulmonary microcirculation is an important physiological property contributing to the maintenance of normal fluid exchange. This has significant implications for our understanding of fluid homeostasis in the healthy lung, edema formation in disease, and reconditioning of donor organs for transplantation

Microbial biomarkers of tree water status for next-generation biomonitoring of forest ecosystems

Next-generation biomonitoring proposes to combine machine-learning algorithms with environmental DNA data to automate the monitoring of the Earth's major ecosystems. In the present study, we searched for molecular biomarkers of tree water status to develop next-generation biomonitoring of forest ecosystems. Because phyllosphere microbial communities respond to both tree physiology and climate change, we investigated whether environmental DNA data from tree phyllosphere could be used as molecular biomarkers of tree water status in forest ecosystems. Using an amplicon sequencing approach, we analysed phyllosphere microbial communities of four tree species (Quercus ilex, Quercus robur, Pinus pinaster and Betula pendula) in a forest experiment composed of irrigated and non-irrigated plots. We used these microbial community data to train a machine-learning algorithm (Random Forest) to classify irrigated and non-irrigated trees. The Random Forest algorithm detected tree water status from phyllosphere microbial community composition with more than 90% accuracy for oak species, and more than 75% for pine and birch. Phyllosphere fungal communities were more informative than phyllosphere bacterial communities in all tree species. Seven fungal amplicon sequence variants were identified as candidates for the development of molecular biomarkers of water status in oak trees. Altogether, our results show that microbial community data from tree phyllosphere provides information on tree water status in forest ecosystems and could be included in next-generation biomonitoring programmes that would use in situ, real-time sequencing of environmental DNA to help monitor the health of European temperate forest ecosystems.</p

PUL807205 Supplemental Material1 - Supplemental material for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium

Supplemental material, PUL807205 Supplemental Material1 for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium by Simon C. Rowan, Lucie Piouceau, Joanna Cornwell, Lili Li and Paul McLoughlin in Pulmonary Circulation</p

PUL807205 Supplemental Material2 - Supplemental material for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium

Supplemental material, PUL807205 Supplemental Material2 for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium by Simon C. Rowan, Lucie Piouceau, Joanna Cornwell, Lili Li and Paul McLoughlin in Pulmonary Circulation</p

PUL807205 Supplemental Material4 - Supplemental material for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium

Supplemental material, PUL807205 Supplemental Material4 for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium by Simon C. Rowan, Lucie Piouceau, Joanna Cornwell, Lili Li and Paul McLoughlin in Pulmonary Circulation</p

PUL807205 Supplemental Material5 - Supplemental material for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium

Supplemental material, PUL807205 Supplemental Material5 for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium by Simon C. Rowan, Lucie Piouceau, Joanna Cornwell, Lili Li and Paul McLoughlin in Pulmonary Circulation</p

PUL807205 Supplemental Material3 - Supplemental material for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium

Supplemental material, PUL807205 Supplemental Material3 for Gremlin 1 blocks vascular endothelial growth factor signaling in the pulmonary microvascular endothelium by Simon C. Rowan, Lucie Piouceau, Joanna Cornwell, Lili Li and Paul McLoughlin in Pulmonary Circulation</p

Coupling ecological network analysis with high-throughput sequencing-based surveys: Lessons from the next-generation biomonitoring project

Biomonitoring ecosystems is necessary in order to evaluate risks and to efficiently manage ecosystems and their associated services. Agrosystems are the target of multiple stressors that can affect many species through effects cascading along food webs. However, classic biomonitoring, focused on species diversity or indicator species, might be a poor predictor of the risk of such whole-ecosystem perturbations. Thanks to high-throughput sequencing methods, however, it might be possible to obtain sufficient information about entire ecological communities to infer the functioning of their associated interaction networks, and thus monitor more closely the risk of the collapse of entire food webs due to external stressors.In the course of the ‘next-generation biomonitoring’ project, we collectively sought to experiment with this idea of inferring ecological networks on the basis of metabarcoding information gathered on different systems. We here give an overview of issues and preliminary results associated with this endeavour and highlight the main difficulties that such next-generation biomonitoring is still facing. Going from sampling protocols up to methods for comparing inferred networks, through biomolecular, bioinformatic, and network inference, we review all steps of the process, with a view towards generality and transferability towards other systems.Biosurveillance Next-Gen des changements dans la structure et le fonctionnement des écosystèmesAdaptation et résilience des réseaux écologiques spatialisés face aux changements d'origine humain