Biology subjects

Wielpuetz, M. O.

Publications and source records attributed to Wielpuetz, M. O..

3 recordsLinked to original sources

bioRxiv2024

Vapor-based Fixation of Pulmonary Tissue in its Physiological State: A Novel Approach to Histological Validation of Ultra High Resolution Phase Contrast CT in Human Sized Lungs

Lung diseases continue to present a major burden on public health. Therefore, improving the process of diagnosis by the development of novel imaging techniques is of great importance. In this perspective, phase sensitive CT imaging techniques such as propagation based imaging (PBI) might play an important role as they allow increasing the spatial resolution at very low x-ray dose levels that are comparable to clinical CT. However, the development of such methods is not only hindered by technological problems but also by the lack of precise validation strategies. We adapted formaldehyde (FA) vapor fixation to demonstrate that fresh porcine lungs that have been investigated by PBI can be fixed in their physiological shape and studied by multi-scale microCT imaging as well as classical histology. In addition, we show that FA vapor fixed pig lungs can be scanned by PBI without visible deterioration of image quality compared to fresh tissue. This opens the possibility of fixing and storing, for instance, human lung tissue before performing a PBI experiment, which in turn allows to study pathological changes in human lungs without questioning the translate-ability of findings in pig lung. The setup can be used by any interested researchers.

pathology↗

bioRxiv2024

Integrative Imaging of Lung Micro Structure: Amplifying Classical Histology by Paraffin Block μCT and same-slide Scanning Electron Microscopy

Classical histopathology of formalin fixed and paraffin embedded (FFPE) tissue using light microscopy (LM) remains the undisputed gold standard in biomedical microstructural lung tissue analysis. To extend this method, we developed an integrative imaging and processing pipeline which adds 3D context and screening capabilities by micro-CT (CT) imaging of the entire paraffin block and adds ultrastructural information by correlative same-slide scanning electron microscopy (SEM). The different modalities are integrated by elastic registration to provide hybrid image datasets. Without compromising standard light microscopic readout, we overcome the limitations of conventional histology by combining and integrating several imaging modalities. The biochemical information contained in histological and immunohistological tissue staining is embedded into the 3D tissue configuration and is amplified by adding ultrastructural visualization of features of interest. By combining CT and conventional histological processing, specimens can be screened, and specifically preselected areas of interest can be targeted in the subsequent sectioning process. While most of the CT data shown in the manuscript was acquired at a Synchrotron, we further demonstrate that our workflow can also by applied using X-ray microscopy.

pathology↗

bioRxiv2023

Longitudinal Micro-Computed Tomography Detects Onset and Progression of Pulmonary Fibrosis in Conditional Nedd4-2 Deficient Mice

ObjectivesIdiopathic pulmonary fibrosis (IPF) is a fatal lung disease which is usually diagnosed late in advanced stages. Little is known about the subclinical development of IPF. We previously generated a mouse model with conditional Nedd4-2 deficiency (Nedd4-2-/-) that develops IPF-like lung disease. The aim of this study was to characterize the onset and progression of IPF-like lung disease in conditional Nedd4-2-/- mice by longitudinal micro- computed tomography (CT). MethodsIn vivo micro-CT was performed longitudinally in control and conditional Nedd4- 2-/- mice at 1, 2, 3, 4 and 5 months after doxycycline induction. Further, terminal in vivo micro-CT followed by pulmonary function testing and post mortem micro-CT was performed in age-matched mice. Micro-CT images were evaluated for pulmonary fibrosis using an adapted fibrosis scoring system. ResultsMicro-CT is sensitive to detect onset and progression of pulmonary fibrosis in vivo and to quantify distinct radiological IPF-like features along disease development in conditional Nedd4-2-/- mice. Nonspecific interstitial alterations were detected from 3 months, whereas key features such as honeycombing-like lesions were detected from 4 months onwards. Pulmonary function inversely correlated with in vivo (r=-0.725) and post mortem (r=-0.535) micro-CT fibrosis scores. ConclusionLongitudinal micro-CT enables in vivo monitoring of onset and progression and detects radiologic key features of IPF-like lung disease in conditional Nedd4-2-/- mice. Our data support micro-CT as sensitive quantitative endpoint for preclinical evaluation of novel antifibrotic strategies. NEW & NOTEWORTHYIPF diagnosis, particularly in early stages, remains challenging. In this study micro-CT is used in conditional Nedd4-2-/- mice to closely monitor the onset and progression of IPF-like lung disease. This allowed us to track for the first time how nonspecific lung lesions develop into key IPF-like features. This approach offers a non-invasive method to monitor pulmonary fibrosis in vivo, providing a quantitative endpoint for preclinical evaluation of novel antifibrotic strategies.

pathology↗