Explore the vast range of titles available.

Tau pathology of the noradrenergic locus coeruleus (LC) is a hallmark of several age-related neurodegenerative disorders, including Alzheimer’s disease. However, a comprehensive neuropathological examination of the LC is difficult due to its small size and rod-like shape. To investigate the LC cytoarchitecture and tau cytoskeletal pathology in relation to possible propagation patterns of disease-associated tau in an unprecedented large-scale three-dimensional view, we utilized volume immunostaining and optical clearing technology combined with light sheet fluorescence microscopy. We examined AT8+ pathological tau in the LC/pericoerulear region of 20 brains from Braak neurofibrillary tangle (NFT) stage 0–6. We demonstrate an intriguing morphological complexity and heterogeneity of AT8+ cellular structures in the LC, representing various intracellular stages of NFT maturation and their diverse transition forms. We describe novel morphologies of neuronal tau pathology such as AT8+ cells with fine filamentous somatic protrusions or with disintegrating soma. We show that gradual dendritic atrophy is the first morphological sign of the degeneration of tangle-bearing neurons, even preceding axonal lesions. Interestingly, irrespective of the Braak NFT stage, tau pathology is more advanced in the dorsal LC that preferentially projects to vulnerable forebrain regions in Alzheimer’s disease, like the hippocampus or neocortical areas, compared to the ventral LC projecting to the cerebellum and medulla. Moreover, already in the precortical Braak 0 stage, 3D analysis reveals clustering tendency and dendro-dendritic close appositions of AT8+ LC neurons, AT8+ long axons of NFT-bearing cells that join the ascending dorsal noradrenergic bundle after leaving the LC, as well as AT8+ processes of NFT-bearing LC neurons that target the 4th ventricle wall. Our study suggests that the unique cytoarchitecture, comprised of a densely packed and dendritically extensively interconnected neuronal network with long projections, makes the human LC to be an ideal anatomical template for early accumulation and trans-neuronal spreading of hyperphosphorylated tau.

Two-photon excitation in light-sheet microscopy advances applications to live imaging of multicellular organisms. In a previous study, we developed a two-photon Bessel beam light-sheet microscope with a nearly 1-mm field of view and less than 4-μm axial resolution, using a low magnification (10×), middle numerical aperture (NA 0.5) detection objective. In this study, we aimed to construct a light-sheet microscope with higher resolution imaging while maintaining the large field of view, using low magnification (16×) with a high NA 0.8 objective. To address potential illumination and detection mismatch, we investigated the use of a depth of focus (DOF) extension method. Specifically, we used a stair-step device composed of five-layer annular zones that extended DOF two-fold, enough to cover the light-sheet thickness. Resolution measurements using fluorescent beads showed that the reduction in resolutions was small. We then applied this system to in vivo imaging of medaka fish and found that image quality degradation at the distal site of the beam injection could be compensated. This demonstrates that the extended DOF system combined with wide-field two-photon light-sheet microscopy offers a simple and easy setup for live imaging application of large multicellular organism specimens with sub-cellular resolution.

Many efforts targeting amyloid‐β (Aβ) plaques for the treatment of Alzheimer's Disease thus far have resulted in failures during clinical trials. Regional and temporal heterogeneity of efficacy and dependence on plaque maturity may have contributed to these disappointing outcomes. In this study, we mapped the regional and temporal specificity of various anti‐Aβ treatments through high‐resolution light‐sheet imaging of electrophoretically cleared brains. We assessed the effect on amyloid plaque formation and growth in Thy1‐APP/PS1 mice subjected to β‐secretase inhibitors, polythiophenes, or anti‐Aβ antibodies. Each treatment showed unique spatiotemporal Aβ clearance, with polythiophenes emerging as a potent anti‐Aβ compound. Furthermore, aligning with a spatial‐transcriptomic atlas revealed transcripts that correlate with the efficacy of each Aβ therapy. As observed in this study, there is a striking dependence of specific treatments on the location and maturity of Aβ plaques. This may also contribute to the clinical trial failures of Aβ‐therapies, suggesting that combinatorial regimens may be significantly more effective in clearing amyloid deposition. Synopsis The brain is highly compartmentalized with many distinct regions. It is unknown how drugs for treating Alzheimer's Disease (AD) work across brain regions and disease stages. We developed a technology to quantify the effects of different AD drugs throughout the brain at different time points. A novel technology was developed for high‐throughput optical mouse brain clarification and staining of Aβ plaques, followed by lightsheet imaging, brain atlas registration, and plaque morphology quantification. Mice were treated with either a BACE1 inhibitor, a polythiophene for stabilizing amyloid fibrils, or an anti‐Aβ antibody. Quantitative results show distinct Aβ plaque modification and removal across brain regions and disease stage. Spatial efficacy profiles of anti‐Aβ therapies were correlated with gene expression maps using a spatial transcriptomics brain atlas. Graphical Abstract The brain is highly compartmentalized with many distinct regions. It is unknown how drugs for treating Alzheimer's Disease (AD) work across brain regions and disease stages. We developed a technology to quantify the effects of different AD drugs throughout the brain at different time points.

Structural and molecular imaging of the developing embryo can provide deep insights into the development of various pathologies, but few techniques enable the simultaneous detection of these parameters. We demonstrate the first use of combined optical coherence tomography and two-photon light sheet fluorescence microscopy (2P-LSFM) for simultaneous structural and molecular imaging. We aim to develop a multimodal high-resolution embryonic system that facilitates simultaneous structural and molecular embryonic imaging. We have developed a multimodal imaging system in which the optical coherence tomography (OCT) and light sheet illumination beams were optically co-aligned and scanned through the galvanometer-mounted mirrors and the same illumination objective. The swept-source OCT system provides a lateral resolution of and an axial resolution of . The 2P-LSFM light sheet thickness was , and the transverse resolution was . We have demonstrated the system's capabilities using fluorescent microbeads and fluorescently tagged mouse embryos. The co-alignment of the OCT and 2P-LSFM systems enables simple image registration and high-throughput multimodal imaging.

In three‐dimensional (3D) space, an unbiased and systemic view of human specimens between structures and functions is required. However, conventional histological sections from specimens have made only limited progress in exploring intact information about 3D biological tissues. With significant advances in optical physics and chemical engineering, state‐of‐the‐art tissue‐clearing methods can revolutionize the intact subcellular level of human tissue histological analysis, from thick human tissues to intact human organs. The present review summarizes the principle of tissue clearing so that a trainee researcher can implement effective human tissue‐clearing protocols. Furthermore, this review highlights existing tissue‐clearing methods in specific human tissue applications, describes imaging strategies, and presents various efficient computational approaches for processing and visualizing large image data. Finally, potential future directions for developing tissue‐clearing methods for human tissues are also discussed.

In recent years, technological advances in tissue preparation, high‐throughput volumetric microscopy, and computational infrastructure have enabled rapid developments in nondestructive 3D pathology, in which high‐resolution histologic datasets are obtained from thick tissue specimens, such as whole biopsies, without the need for physical sectioning onto glass slides. While 3D pathology generates massive datasets that are attractive for automated computational analysis, there is also a desire to use 3D pathology to improve the visual assessment of tissue histology. In this perspective, we discuss and provide examples of potential advantages of 3D pathology for the visual assessment of clinical specimens and the challenges of dealing with large 3D datasets (of individual or multiple specimens) that pathologists have not been trained to interpret. We discuss the need for artificial intelligence triaging algorithms and explainable analysis methods to assist pathologists or other domain experts in the interpretation of these novel, often complex, large datasets.

Tumor structure is heterogeneous and complex, and it is difficult to obtain complete characteristics by two‐dimensional analysis. The aim of this study was to visualize and characterize volumetric vascular information of clear cell renal cell carcinoma (ccRCC) tumors using whole tissue phenotyping and three‐dimensional light‐sheet microscopy. Here, we used the diagnosing immunolabeled paraffin‐embedded cleared organs pipeline for tissue clearing, immunolabeling, and three‐dimensional imaging. The spatial distributions of CD34, which targets blood vessels, and LYVE‐1, which targets lymphatic vessels, were examined by calculating three‐dimensional density, vessel length, vessel radius, and density curves, such as skewness, kurtosis, and variance of the expression. We then examined those associations with ccRCC outcomes and genetic alteration state. Formalin‐fixed paraffin‐embedded tumor samples from 46 ccRCC patients were included in the study. Receiver operating characteristic curve analyses revealed the associations between blood vessel and lymphatic vessel distributions and pathological factors such as a high nuclear grade, large tumor size, and the presence of venous invasion. Furthermore, three‐dimensional imaging parameters stratified ccRCC patients regarding survival outcomes. An analysis of genomic alterations based on volumetric vascular information parameters revealed that PI3K‐mTOR pathway mutations related to the blood vessel radius were significantly different. Collectively, we have shown that the spatial elucidation of volumetric vasculature information could be prognostic and may serve as a new biomarker for genomic alterations. High‐end tissue clearing techniques and volumetric immunohistochemistry enable three‐dimensional analysis of tumors, leading to a better understanding of the microvascular structure in the tumor space.

The development of tissue clearing technologies allows 3D imaging of whole tissues and organs, especially in studies of the central nervous system innervated throughout the body. Although the three-dimensional imaging of solvent-cleared organs (3DISCO) method provides a powerful clearing capacity and high transparency, the rapid quenching of endogenous fluorescence and peroxide removal process decreases its practicability. This study provides a modified method named tDISCO to solve these limitations. The tDISCO protocol can preserve AAV-transduced endogenous EGFP fluorescence for months and achieve high transparency in a fast and simple clearing process. In addition to the brain, tDISCO was applied to other organs and even hard bone tissue. tDISCO also enabled us to visualize the long projection neurons and axons with high resolution. This method provides a fast and simple clearing protocol for 3D visualization of the AAV- transduced long projection neurons throughout the brain and spinal cord.

Light‐sheet fluorescence microscopy (LSFM) introduces fast scanning of biological phenomena with deep photon penetration and minimal phototoxicity. This advancement represents a significant shift in 3‐D imaging of large‐scale biological tissues and 4‐D (space + time) imaging of small live animals. The large data associated with LSFM require efficient imaging acquisition and analysis with the use of artificial intelligence (AI)/machine learning (ML) algorithms. To this end, AI/ML‐directed LSFM is an emerging area for multiorgan imaging and tumor diagnostics. This review will present the development of LSFM and highlight various LSFM configurations and designs for multiscale imaging. Optical clearance techniques will be compared for effective reduction in light scattering and optimal deep‐tissue imaging. This review will further depict a diverse range of research and translational applications, from small live organisms to multiorgan imaging to tumor diagnosis. In addition, this review will address AI/ML‐directed imaging reconstruction, including the application of convolutional neural networks (CNNs) and generative adversarial networks (GANs). In summary, the advancements of LSFM have enabled effective and efficient post‐imaging reconstruction and data analyses, underscoring LSFM's contribution to advancing fundamental and translational research. The integration of artificial intelligence in light sheet imaging enhances the precision and efficiency of analyzing complex biological specimens, leading to more detailed and accurate insights into cellular and tissue structures.

State-of-the-art tissue-clearing methods provide subcellular-level optical access to intact tissues from individual organs and even to some entire mammals. When combined with light-sheet microscopy and automated approaches to image analysis, existing tissue-clearing methods can speed up and may reduce the cost of conventional histology by several orders of magnitude. In addition, tissue-clearing chemistry allows whole-organ antibody labelling, which can be applied even to thick human tissues. By combining the most powerful labelling, clearing, imaging and data-analysis tools, scientists are extracting structural and functional cellular and subcellular information on complex mammalian bodies and large human specimens at an accelerated pace. The rapid generation of terabyte-scale imaging data furthermore creates a high demand for efficient computational approaches that tackle challenges in large-scale data analysis and management. In this Review, we discuss how tissue-clearing methods could provide an unbiased, system-level view of mammalian bodies and human specimens and discuss future opportunities for the use of these methods in human neuroscience.Tissue-clearing methods are now allowing 3D imaging of intact tissues and some entire mammals. In this Review, Ueda and colleagues discuss the various tissue-clearing methods, related techniques and data analysis and management, as well as the application of these methods in neuroscience.