How to obtain good morphology and antigen detection in the same tissue section?

Alpha-synuclein in skin as a high-quality biomarker for Parkinson's disease

Parkinson's disease (PD), the most common neurological motor system disorder, which characterised by the irreversible loss of dopaminergic neurones in the substantia nigra pars compacta, and leads to the deficiency of dopamine in the striatum. Deposited Lewy bodies (LBs) in diseased neurones and nerve terminals are the pathological hallmark of PD, and alpha-synuclein (α-Syn) is the most prominent protein in LBs. The tight association between α-Syn and the molecular pathology of PD has generatly increaed the interest in using the α-Syn species as biomarkers to diagnose early PD. α-Syn is not confined to the central nervous system, it is also present in the peripheral tissues, such as human skin. The assessment of skin α-Syn has the potential to be a diagnostic method that not only has excellent sensitivity, specificity, and reproducibility, but also convenient and acceptable to patients. In this review, we (i) integrate the biochemical, aggregation and structural features of α-Syn; (ii) map the distribution of the α-Syn species present in the brain, biological fluids, and peripheral tissues; and (iii) present a critical and comparative analysis of previous studies that have measured α-Syn in the skin. Finally, we provide an outlook on the future of skin biopsy as a diagnostic approach for PD, and highlight its potential implications for clinical trials, clinical decision-making, treatment strategies as well as the development of new therapies.

Virtual measurements of paracellular permeability and chronic inflammation via color coded pixel-wise T1 mapping

To assess whether quantitative T₁ relaxometry can measure permeability, chronic inflammation and mural thickening of mouse bladder wall. Adult female C57BL6 mice unexposed to radiation (controls) or 40 wk postirradiation of 10 Gy were scanned at 9.4 T before and after instillation (0.1 mL) of aqueous, novel contrast mixture (NCM) containing 4 mM gadobutrol and 5 mM ferumoxytol. Rapid acquisition with refocused echo (RARE) sequence was used with variable repetition times (TR). Pixel-wise maps of T₁ relaxation times for the segmented bladder wall layers were generated from voxel-wise, nonlinear least square data fitting of TR-dependent signal intensity acquired with TR array of 0.4-10 s followed by the histology of harvested bladder. Significant differences between precontrast and postcontrast T₁ (ΔT₁) were noted in urothelium and lamina propria of both groups but only in detrusor of irradiated group (P < 0.001; 2-way ANOVA). Nearly twofold higher gadobutrol permeability (550 ± 73 vs. 294 ± 160 μM; P < 0.01) derived as per 1/ΔT₁ = r1. [C] in urothelium of irradiated group. Inflammation and bladder wall thickening (0.75 ± 0. vs. 0.44 ± 0.08 mm; P < 0.001) predicted by MRI was subsequently confirmed by histology and altered expression of CD45 and zonula occludens-1 (ZO-1) relative to controls. NCM enhanced MRI relies on the retention of large molecular weight ferumoxytol in lumen for negative contrast, while permeation of the non-ionic, small molecular weight gadobutrol through ZO-1 generates positive contrast in bladder wall for virtual measurement of paracellular permeability and assessment of chronic inflammation in thin and distensible bladder wall, which is also defined by its variable shape and location within pelvis.

Comparison of Methods for the Histological Evaluation of Odontocete Spiral Ganglion Cells

Cetaceans greatly depend on their hearing system to perform many vital activities. The spiral ganglion is an essential component of the auditory pathway and can even be associated with injuries caused by anthropogenic noise. However, its anatomical location, characterized by surrounding bony structures, makes the anatomical and anatomopathological study of the spiral ganglion a difficult task. In order to obtain high-quality tissue samples, a perfect balance between decalcification and the preservation of neural components must be achieved. In this study, different methodologies for spiral ganglion sample preparation and preservation were evaluated. Hydrochloric acid had the shortest decalcification time but damaged the tissue extensively. Both formic acid and EDTA decalcification solutions had a longer decalcification time but exhibited better preservation of the neurons. However, improved cell morphology and staining were observed on ears pretreated with EDTA solution. Therefore, we suggest that decalcifying methodologies based on EDTA solutions should be used to obtain the highest quality samples for studying cell morphology and antigenicity in cetacean spiral ganglion neurons.

Paraffin Embedding and Thin Sectioning of Microbial Colony Biofilms for Microscopic Analysis

Sectioning via paraffin embedding is a broadly established technique in eukaryotic systems. Here we provide a method for the fixation, embedding, and sectioning of intact microbial colony biofilms using perfused paraffin wax. To adapt this method for use on colony biofilms, we developed techniques for maintaining each sample on its growth substrate and laminating it with an agar overlayer, and added lysine to the fixative solution. These optimizations improve sample retention and preservation of micromorphological features. Samples prepared in this manner are amenable to thin sectioning and imaging by light, fluorescence, and transmission electron microscopy. We have applied this technique to colony biofilms of Pseudomonas aeruginosa, Pseudomonas synxantha, Bacillus subtilis, and Vibrio cholerae. The high level of detail visible in samples generated by this method, combined with reporter strain engineering or the use of specific dyes, can provide exciting insights into the physiology and development of microbial communities.

Co-culturing porcine normal urothelial cells, urinary bladder fibroblasts and smooth muscle cells for tissue engineering research

New strategies for culturing and co-culturing of the main types of urinary bladder cells are essential for successful establishment of biomimetic in vitro models, which could be applied for research into, and management of, diverse urological disorders. Porcine normal urothelial cells are available in nearly unlimited amounts and have many properties equivalent to human urothelial cells. In the present study, we established normal differentiated porcine urothelial cells in co-cultures with porcine urinary bladder normal fibroblasts and/or smooth muscle cells. The optimal culture medium for establishment of differentiated urothelial cells, demonstrated by positive immunofluorescence of uroplakins, cytokeratins (CK 7, CK 20), zonula occludens 1 (ZO-1), claudin 4, claudin 8, and E-cadherin, was the medium composed of equal parts of Advanced Dulbecco's modified Eagle's medium (A-DMEM) and MCDB 153 medium with physiological calcium concentration of 2.5 mM and without fetal bovine serum, named UroM (+Ca²⁺  - S). This medium was also proven to be suitable for culturing of bladder fibroblasts and smooth muscle cells and co-culturing of urothelial cells with these mesenchymal cells. Urothelial cell differentiation was optimal in UroM (+Ca²⁺  - S) medium in all co-culture conditions and when compared to all conditioned-media combinations. To summarize, these strategies for culturing and co-culturing of urinary bladder urothelial cells with mesenchymal cells could be used as new in vitro models for future basic and applicable research of the urinary bladder and thus potentially also for translational tissue engineering studies.