Biology subjects

Ressel, L.

Publications and source records attributed to Ressel, L..

6 recordsLinked to original sources

bioRxiv2026

Assessing the efficacy of human mesenchymal stromal cells of different tissue origins in a mouse model of kidney ischaemia reperfusion injury

Rodent models of kidney disease have been widely used to assess the efficacy, safety and mode of action of mesenchymal stromal cells (MSCs) as therapies. However, because kidney disease models, MSC type and the methods used to assess kidney injury tend to differ between research groups, it is difficult to obtain data that are sufficiently robust and reproducible to support clinical translation. We present here for the first time a side-by-side analysis of the performance of human MSCs derived from the most commonly used tissue sources, bone marrow (BM-), adipose- (A-) and umbilical cord (UC-), in a kidney ischaemia reperfusion injury (IRI) model in mice. For each animal, we performed a comprehensive assessment of kidney function and health by longitudinal transdermal measurements of sinistrin clearance, serum biomarker levels at the experimental endpoint, and histopathological scoring of sections from left and right kidneys. Furthermore, we tracked the MSCs by bioluminescence imaging in the injured mice to determine their viability over time and their capacity for homing to the damaged kidneys. Our results reveal that only modest if any beneficial effects of the MSC treatments were detectable on kidney function and histology, irrespective of cell type administered. Furthermore, all three MSC types were sequestered in the lungs without reaching the kidneys, and had completely disappeared within 7 days. Our data suggest that none of the MSC types has the capability to improve renal health following IRI to a meaningful extent, questioning their suitability as a clinical therapy. Significance StatementMSCs have been proposed as efficacious cell therapies in murine models of kidney disease, with potential for clinical translation. We compare efficacy of human MSCs of different tissue origins (adipose, bone marrow and umbilical cord) in a refined mouse model of renal IRI. Only modest if any beneficial effects on kidney function and histology were detectable for all three cell types, and cells did not reach the kidneys but sequestered in the lungs where they died.

physiology↗

bioRxiv2026

Gut immunity and the bacterial and eukaryotic microbiome of wild house mice.

It is well established that the microbiome can have major effects on animal biology. Here we have investigated the composition of the bacterial and eukaryotic gut microbiome of wild mice from three sample sites and sought to understand what affects its composition. We find that the bacterial and eukaryotic microbiome differs among mice from different sites. Among mouse traits, we found that only gut inflammation and the concentration of faecal immunoglobulin A affected the microbiome diversity. However, the microbiome diversity was more commonly affected by the microbiome composition itself, both within-bacterial and within-eukaryotic, but also by cross bacterial-eukaryotic effects. We found that most hosts produce IgA that binds some of their gut bacteria, though mice are largely idiosyncratic in which taxa they bind with IgA, with a few taxa commonly IgA-bound. The eukaryotic microbiome was dominated by fungal taxa, and included Eimeria infection that was particularly common at one of the sites. At the high Eimeria prevalence site, mice had comparatively marked caecal inflammation and significantly greater IgA responses. Our results emphasise the substantial among-individual mouse differences in gut microbiome composition, gut physiology and immunology, and the biological significance of the bacterial-eukaryotic effects that we suggest requires further study.

ecology↗

bioRxiv2022

Comparison between optical tissue clearing methods for detecting administered mesenchymal stromal cells in mouse lungs

Optical tissue clearing of lung tissue enables the intact lung to be imaged using fluorescence microscopy. Several clearing protocols have been developed in recent years, including the Clear, Unobstructed Brain/Body Imaging Cocktails and Computational analysis (CUBIC), stabilised 3D imaging of solvent-cleared organs (s-DISCO) and Ethyl cinnamate (ECi) methods. Here we compared these protocols with the aim of determining the biodistribution of mesenchymal stroma cells (MSCs) and understanding how they interact with host cells in the mouse lung. First, we evaluated how each method affected the size, morphology, and transparency of the lungs. Then, we compared the preservation of the fluorescence of the protein tdTomato expressed by the MSCs, and of the organic dye Evans Blue which labels the vasculature. In addition, we tested the compatibility of the methods with immunofluorescence staining. We found that CUBIC clearing is the only method that enables direct imaging of fluorescently labelled MSCs in the lungs thereby allowing the study of the MSC interaction with endothelial and immune cells when combined with immunofluorescence staining. Overall, 3D imaging of CUBIC cleared lungs confirmed that injected MSCs are initially retained in the pulmonary microvasculature, and that most cells are eliminated from the lungs within the first 24 h. Summary statementWe present a tissue clearing approach to visualize exogenous MSCs in the mouse lung and study their effects in the host.

physiology↗

bioRxiv2019

Murine models of renal ischaemia reperfusion injury: An opportunity for refinement using non-invasive monitoring methods

BackgroundRenal Ischaemia Reperfusion Injury (R-IRI) can cause Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD), resulting in significant morbidity and mortality. To understand the underlying mechanisms, reproducible small-animal models of AKI and CKD are needed. We describe how innovative technologies for measuring kidney function non-invasively in small rodents allow successful refinement of the R-IRI models, and offer the unique opportunity to monitor longitudinally in individual animals the transition from AKI to CKD. MethodsMale BALB/c mice underwent bilateral renal pedicle clamping (AKI) or unilateral renal pedicle clamping with delayed contralateral nephrectomy (CKD) under isoflurane anaesthetic. Transdermal GFR monitoring and multi-spectral optoacoustic tomography in combination with statistical analysis were used to identify and standardise variables within these models. ResultsPre-clamping anaesthetic time was one of the most important predictors of AKI severity after R-IRI. Standardising pre-clamping time resulted in a more predictably severe AKI model. In the CKD model, initial improvement in renal function was followed by significant progressive reduction in function between weeks 2 and 4. Performing contralateral nephrectomy on day 14 enabled the development of CKD in a survivable way. ConclusionsNon-invasive monitoring of global and individual renal function after R-IRI is feasible, reproducible and correlates well with classical markers of injury. This facilitates refinement of kidney injury models and enables the degree of injury seen in pre-clinical models to be translated to those seen in the clinical setting. Thus, future therapies can be tested in a clinically relevant, non-invasive manner. What is already knownThe severity of Renal Ischaemia Reperfusion injury (R-IRI) varies between animal strain, gender and age. Experimental variables including temperature and clamping time are usually tightly controlled but significant variability still exists. Classically, small rodent experiments depend on endpoint evaluation of serum and histological features of disease. However, new technologies including transdermal glomerular filtration rate (GFR) monitoring and Multispectral Optoacoustic Tomography (MSOT) may enable renal function to be accurately monitored longitudinally, enabling better refinement of these models. What this study addsThis study shows that transdermal GFR measurements have reliably enabled refinement of the R-IRI model by standardisation of the duration of isoflurane prior to commencing surgery. Individual kidney function can be assessed in-vivo after unilateral R-IRI using MSOT imaging. The excretion tmax of IRDye-800 reliably represents the relative function of the injured kidney, permitting longitudinal in-vivo assessment of differential kidney function. What impact this may have on practiceThis study demonstrates the utility of two minimally-invasive in-vivo methods of monitoring kidney function which have advantages over classical methods and potentially enable fewer animals to be used in future studies. The study demonstrates refinement of bilateral and unilateral R-IRI models which will also enable a reduction in the number of animals needed for experimentation.

physiology↗

bioRxiv2018

Development of an imaging toolbox to assess the therapeutic potential and biodistribution of macrophages in a mouse model of multiple organ dysfunction

Cell-based regenerative medicine therapies require robust preclinical safety, efficacy, biodistribution and engraftment data prior to clinical testing. To address these challenges, we have developed an imaging toolbox comprising multi-spectral optoacoustic tomography and ultrasonography, which allows the degree of kidney, liver and cardiac injury and the extent of functional recovery to be assessed non-invasively in a mouse model of multi-organ dysfunction. This toolbox allowed us to determine the therapeutic effects of adoptively transferred M2 macrophages. Using bioluminescence imaging, we could then investigate the association between amelioration and biodistribution. Macrophage therapy improved kidney and liver function to a limited extent, but did not ameliorate histological damage. No improvement in cardiac function was observed. Biodistribution analysis showed that macrophages homed and persisted in the injured kidneys and liver, but did not populate the heart. Our data suggest that the limited improvement observed in kidney and liver function could be mediated by M2 macrophages.

pharmacology and toxicology↗

bioRxiv2017

Non-invasive imaging platform reveals a potential tumourigenicity hazard of systemically administered cells

BackgroundCell-based regenerative medicine therapies are now frequently tested in clinical trials. In many conditions, cell therapies are administered systemically, but there is little understanding of their fate, and adverse events are often under-reported. Currently, it is only possible to assess safety and fate of cell therapies in preclinical studies, specifically by monitoring animals longitudinally using multimodal imaging approaches. Here, using a suite of in vivo imaging modalities to explore the fate of a range of human and murine cells, we investigate how route of administration, cell type and host immune status affect the fate of administered cells.\n\nMethodsWe applied a unique imaging toolkit combining bioluminescence, optoacoustic and magnetic resonance imaging modalities to assess the safety of different human and murine cell types by following their biodistribution and persistence in mice following administration into the venous or arterial system. Results: Longitudinal imaging analyses (i) suggested that the intra-arterial route may be more hazardous than intravenous administration for certain cell types; (ii) revealed that the potential of a mouse mesenchymal stem/stromal cell (MSC) line to form tumours, depended on administration route and mouse strain; and (iii) indicated that clinically tested human umbilical cord (hUC)-derived MSCs can transiently and unexpectedly proliferate when administered intravenously to mice.\n\nConclusionsIn order to perform an adequate safety assessment of potential cell-based therapies, a thorough understanding of cell biodistribution and fate post administration is required. The non-invasive imaging toolbox used here can expose not only the general organ distribution of these therapies, but also a detailed view of their presence within different organs and, importantly, tumourigenic potential. Our observation that the hUC-MSCs but not the human bone marrow (hBM)-derived MSCs persisted for a period in some animals, suggests that therapies with these cells should proceed with caution.

cell biology↗