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Enzyme-grafted nylon membranes for enhanced protein recovery from microalgae Tetraselmis chui
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Thermo-rheological properties of xanthan solutions: from shear thinning to elasto-viscoplastic behavior
No full textInternational audienceThe thermo-rheological behavior of xanthan solutions with concentrations spanning a wide range is investigated experimentally. After carefully identifying four distinct regimes of concentration we focused on highly concentrated xanthan solutions. By combining several rheological techniques, it is shown for the first time that such solutions belong to the broad class of elasto-viscoplastic materials by exhibiting both a yield stress and elasticity that manifests around the solid–fluid transition. The soft and weakly entangled structure responsible for the elasto-viscoplastic rheological behavior is controlled by two factors:imposed stress, temperature. Consequently, concentrated solutions of xanthan may yield to either imposed stress or temperature. The systematic analysis of the elasticity mediate solid–fluid transition at various operating temperatures revealed the presence of a novel state termed as ‘‘molten solid’’. A clear relationship between the rheological states and the molecular states (native, denaturated, re-naturated) is establishe
Biofabrication of an ovine intervertebral disc model by combining a polycaprolactone frame with a bioprinted alginate hydrogel
No full textInternational audienceThe intervertebral disc (IVD) primarily comprises an outer ring of collagen fibers (annulus fibrosus, AF), which encases a soft, gelatinous core (nucleus pulposus, NP). Existing in vitro models have failed to integrate these two tissues effectively or accurately replicate their intricate organization. By combining two biofabrication techniques, we developed a novel 3D in vitro model that closely mimics the organization of an ovine IVD. Our approach employs a polycaprolactone (PCL) frame produced via melt electrowriting to recreate the multilamellar architecture of the AF. Ovine primary cells, encapsulated in a photocrosslinkable alginate hydrogel, were precisely extruded within the multilamellar structure, thereby mimicking the native shape and size of an ovine disc. The bioink containing the NP cells was deposited at the center of the construct, while the bioink with the AF cells was strategically layered in between the lamellae of the PCL frame. Photocrosslinking was optimized to match the native stiffness of the disc. The constructs were maintained in culture for 28 d, during which we thoroughly assessed reproducibility, stability, and cell viability and phenotype. The results unequivocally demonstrated that the PCL frame effectively guided the alignment and proliferation of AF cells, while the alginate hydrogel preserved NP cell phenotype. This model successfully replicates the organization of the IVD, providing a promising platform for advancing our understanding of disc biology and driving the development of novel therapeutic strategies
Synovial MS4A4A correlates with inflammation and counteracts response to corticosteroids in arthritis
No full textInternational audienceMS4A4A belongs to the MS4A tetraspan protein superfamily and is selectively expressed by the monocyte-macrophage lineage. In this study, we aimed to evaluate the role of MS4A4A+ macrophages in rheumatoid arthritis (RA) pathogenesis and response to treatment. RNA sequencing and immunohistochemistry of synovial samples from either early treatment-naïve or active chronic RA patients showed that MS4A4A expression positively correlated with synovial inflammation. Synovial macrophages from patients treated with corticosteroids (CS) exhibited an enhanced expression of MS4A4A and Fc γ receptor (FcγR) 3. Accordingly, CS enhanced in vitro the expression of MS4A4A and FcγR3 in human and murine macrophages. In an experimental model of arthritis, Ms4a4a deletion had no effect on the disease course but was associated with enhanced therapeutic response selectively to CS. These results suggest that macrophage expression of MS4A4A represents a biomarker of joint inflammation in RA and that its upregulation in concert with FcγR3 by CS counteracts the therapeutic activity of these drugs. Macrophage MS4A4A may represent a biomarker of joint inflammation in RA and a target to amplify the therapeutic activity of CS
Dairy supply chain and climate change impacts on food safety: Learnings from PROTECT-ITN
No full textInternational audienceThe dairy supply chain is among the sectors to be impacted by climate change. This lecture will highlight the results of a European project PROTECT-ITN (PRedictive mOdelling Tools to evaluate the Effects of Climate change on food safeTy). The structure follows the impact-modelling-mitigation paradigm in understanding and responding to the threats of climate change. First, the impact of climate change on raw milk was mapped out, summarizing the existing literature. Second, case studies demonstrating the modelling approaches for modelling the impacts of climate change on dairy products by microbial and chemical hazards. These case studies reflect the different dairy supply chains in the Middle East and European regions. Third, the mitigation part highlights the need for mitigation strategies, considering their additional environmental impact and the need for a holistic framework
Valve-in-valve transcatheter aortic valve replacement versus redo surgical aortic valve replacement in patients with degenerated aortic bioprostheses: Three-year death rates and haemodynamic performance
No full textInternational audienceBackground: Management of degenerated aortic bioprostheses through valve-in-valve transcatheter aortic valve replacement (ViV-TAVR) or redo surgical aortic valve replacement (Re-SAVR) shows similar short-term safety and efficacy. However, long-term survival and haemodynamic performance data are limited.Aim: To compare clinical characteristics, haemodynamics and outcomes at 3 years between ViV-TAVR and Re-SAVR techniques.Methods: This retrospective two-centre study included 266 patients treated for isolated aortic bioprosthesis degeneration (130 Re-SAVR, 136ViV-TAVR) from 2009 to 2018, with up to 3 years of follow-up.Results: The ViV-TAVR group was older (83 vs. 77 years; P=0.005) with higher surgical risk (Logistic EuroSCORE 22% vs. 13%; P=0.005). At 3 years, univariate analysis showed no significant difference in all-cause deaths (22.1% vs. 17.7%; P=0.37). ViV-TAVR was associated with fewer first-month complications, including major bleeding (11.0% vs. 52.3%; P=0.007) and acute renal failure grade 2/3 (5.1% vs. 14.6%; P=0.053). Inverse probability of treatment weighting analysis revealed no difference in all-cause deaths at 1 year (hazard ratio [HR] 0.78, 95% confidence interval [CI] 0.36-1.67; P=0.52) or between 1 and 3 years (HR 1.56, 95% CI 0.82-2.99; P=0.17). Composite events were similar at 1 year (HR 0.80, 95% CI 0.44-1.44; P=0.45) and between 1 and 3 years (HR 1.41, 95% CI 0.83-2.38; P=0.21). Mean gradients at 3 years were similar (16.1±11.4 vs. 13.2±5.3mmHg; P=0.17). In patients with small bioprostheses (true internal diameter≤20mm [n=151]), death rates at 3 years were similar (21.1% vs. 20.0%; P=0.86), as was haemodynamic performance (mean gradient 19.2±14.0mmHg for ViV-TAVR vs. 13.7±4.12mmHg for Re-SAVR [P=0.38]). Compared to balloon-expandable, self-expandable valves showed better 1-year mean gradients (16.4±10.5 vs. 13.7±4.12mmHg; P=0.012).Conclusions: ViV-TAVR and Re-SAVR had similar mortality and haemodynamic outcomes at 3 years, including in patients with small bioprostheses where self-expandable valves yielded the best results
A Fragile Phosphate/Pyrophosphate Balance: From Essential Mineralization to Rare Calcifying Diseases
No full textInternational audiencePurpose of ReviewCalcification, the deposition of phosphate-calcium crystals, is essential for the development and function of mineralized tissues. When dysregulated, it can cause harmful effects. This review focuses on the critical role of the balance between phosphate (Pi) and pyrophosphate (PPi) in maintaining healthy mineralization and explains how disruptions in this balance contribute to rare calcifying disorders.Recent FindingsStudies have identified key regulators of PPi production and Pi generation. Recent research on rare calcifying diseases and animal models has revealed how Pi/PPi imbalances lead to ectopic calcification in soft tissues, driving disease progression.SummaryThe balance of Pi/PPi is vital for bone health and preventing pathological calcification. Disruptions in this equilibrium contribute to rare diseases. Understanding these mechanisms, supported by preclinical models, opens potential therapeutic avenues to restore balance and mitigate the impact of these diseases
Enhancing ecosystem services in cattle farming Insights from the PRESENCE project
No full textInternational audienceCattle farming, crucial to the agricultural economy and landscape multifunctionality in nothwestern France, has declined over the past two decades. This study, part of the PRESENCE project (ImPRove Ecosystemic SErvices of bovine livestoCk in tErritories), synthesizes findings from three interconnected phases to assess and enhance the multifunctionality of cattle farming at the territorial scale. Surveys (n=20) done during phase 1 (2023) across three areas revealed that, while ecosystem services (ES) concepts are not always explicitly recognized by stakeholders, their valuation depends on territorial and ecological contexts. Public-private collaborations, supported by policy tools (such as labels), help structure ES provision and aligning cattle farming with local sustainability goals. In phase 2 (2023), a survey of 65 cattle farms across the three areas identified 11 farm types (4 dairy, 5 suckler, 2 mixed) and 5 ES bundles using factorial analysis and hierarchical clustering. Dairy and mixed systems significantly contribute to food production and employment, while suckler and grass-based systems enhance biodiversity and rural vitality. These findings underscore the need for refined methodologies to characterize ES provision across diverse farming systems. Phase 3 (2025), a targeted survey of 30 farms in one area analyzes the links between feeding strategies, agrobiodiversity, and land-use configurations. It also stresses out the impact of climate and economic pressures on feeding strategy. This research improves understanding of how cattle farming systems interact with socio-ecological environments, informing policies that support both productive and ES-oriented practices. By integrating feed management, farm diversity, and territorial dynamics, this work aids the transition to sustainable cattle production
Improving a green process for Cryptophycin production from cyanobacteria biomass
No full textInternational audienceIntroductionA filamentous strain, Nostoc sp. ATCC 53789 is known to produce a bioactive cyclo-depsipeptide, Cryptophycin (Cr) (1). The objective of this study is to enhance the green Cr yield through the utilisation of ecophysiological analysis of cyanobacteria cultures and the performance of unit operations involved in biomass treatment.Materials and MethodsThe strain is cultivated in a specially formulated, artificial medium, enabling precise modulation of its composition. Continuous or semi-continuous cultures are carried out in closed photobioreactors. It allows for precise control of the environmental parameters necessary for eco-physiological studies. Extraction and purification used liquid/ solid and liquid/liquid separative and preparative techniques (CPC and LC-prep). The focus is on achieving a criticalequilibrium of Cr between two immiscible bio-renewable solvents. Cr content is monitored by LC-DAD and LC-MS.ResultsOptimal values for the composition of the culture medium and light fluxes were determined to increase the biomass productivity of the cyanobacteria. An increase in Cr content is observed when dinitrogen is the only N-source (diazotrophy). Then Cr productivity was also improved.Studying the filamentous aggregation process of this species led to the implementation of a pre-harvest process.This involves the use of a simple fine filter screen, which reduces power consumption.The study demonstrated the potential for highly efficient extraction and purification, even with biorenewable solvents like limonene.ConclusionThe results demonstrate that biological production involves fewer steps than chemical synthesis and, most notably, utilises a range of bio-renewable inputs, including N2 and limonene. The scalability of the process is addressed in the context of the quantities requested for potential pharmaceutical applications
