High-Speed Human Temporal Bone Sectioning for the Assessment of COVID-19-Associated Middle Ear Pathology
May 18th, 2022
This article describes a technique for rapid human temporal bone sectioning that utilizes a microsaw with twin diamond blades to generate thin slices for rapid decalcification and analysis of temporal bone immunohistochemistry.
This protocol reduces the time for temporal bone processing from 9 to 10 months to 10 to 14 days. The main advantage of this technique is it allows for the rapid assessment of otopathology, which in our case is relevant for the assessment of COVID-19-associated middle ear pathology. This technique may be particularly helpful for time-sensitive studies of the temporal bone.
In the future, it may be further optimized for use studying inner ear pathology. Begin the harvest during autopsy and divide the cranial nerves sharply to the internal auditory canal. Make the first bony incision with the osteotome parallel to and just medial to the squamous portion of the temporal bone.
Then, perform the second bony incision parallel to the first at the medial border of the temporal bone. Make the third incision at three to four centimeters anterior and parallel to the petrous ridge. Next, make the fourth incision roughly parallel to the third at two centimeters posterior to the petrous ridge.
Use sharp dissection to free the soft tissue attached along the inferior edge of the specimen and remove the temporal bone. After the harvest, immediately submerge the tissue in 200 to 300 milliliters of 10%buffered formalin. Then, set a precision microsaw with twin diamond blades to a distance of five millimeters.
For rapid tissue decalcification, cut each specimen into three sections such that the central section of the temporal bone is five millimeters thick and those on either end are three to five millimeters thick. Place the sections in 200 to 300 milliliters of 0.37-molar EDTA for seven to 10 days at room temperature for softening. Hematoxylin and eosin staining of the middle ear mucosa and eustachian tube showed that the tissue is preserved after processing using this protocol.
Immunohistochemical analyses showed the presence of ACE2, transmembrane protease serine, and furin proteins within these tissues, providing a possible root for SARS-CoV2 infection in the respiratory epithelium of the middle ear. It is important to appropriately position the temporal bone tissue within the diamond saw. Alternative techniques that can be combined with this method include immunohistochemistry for different proteins, different tissue stains, and transcriptomics.
This technique allowed us to rapidly assess for the presence of the proteins involved in SARS-CoV2 infection within the middle ear during the COVID-19 pandemic.
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Overview
This article describes a technique for rapid human temporal bone sectioning using a microsaw with twin diamond blades. This method significantly reduces the time required for temporal bone processing, facilitating quicker analysis of immunohistochemistry.
Key Study Components
Area of Science
- Neuroscience
- Otopathology
- Immunohistochemistry
Background
- Traditional temporal bone processing can take 9 to 10 months.
- Rapid assessment of otopathology is crucial for timely research.
- This technique is relevant for studying COVID-19-associated middle ear pathology.
- Future optimization may enhance studies of inner ear pathology.
Purpose of Study
- To reduce processing time for temporal bone analysis.
- To enable rapid assessment of otopathology.
- To provide a method applicable to time-sensitive studies.
Methods Used
- Harvesting during autopsy.
- Sharp division of cranial nerves to the internal auditory canal.
- Initial bony incision made with an osteotome.
- Use of a microsaw with twin diamond blades for sectioning.
Main Results
- Processing time reduced from 9-10 months to 10-14 days.
- Facilitates rapid assessment of middle ear pathology.
- Potential for further optimization in future studies.
- Applicable for urgent research needs in otopathology.
Conclusions
- The technique significantly accelerates temporal bone processing.
- It is particularly useful for studies related to COVID-19.
- Future research may enhance its application in inner ear pathology.
Frequently Asked Questions
Executive Industry Relevance
Accelerated temporal bone sectioning enables rapid histopathologic assessment of middle ear tissues, addressing urgent research needs during infectious disease outbreaks such as COVID-19. By reducing tissue processing time from months to days, this method supports time-sensitive target validation and mechanistic studies in otopathology. The approach enhances portfolio agility for translational research teams investigating viral entry pathways and tissue-specific protein expression.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables rapid interrogation of protein expression relevant to viral entry mechanisms in human tissues.
- Supports functional target validation by preserving tissue integrity for immunohistochemical analysis.
- Facilitates mechanistic de-risking in studies of pathogen-host interactions within the middle ear.
Screening & Assay Development
- Provides high-quality tissue sections suitable for standardized immunohistochemistry and molecular assays.
- Reduces turnaround time for assay development and validation in otopathology research.
- Improves reproducibility and scalability of tissue-based screening workflows.
Translational & Preclinical Research
- Enables alignment of tissue-based findings with translational biomarker studies in infectious disease models.
- Supports continuity from discovery through preclinical validation by expediting tissue analysis.
- Reduces risk of delayed insights in urgent public health contexts.
Pipeline & Workflow Integration
This rapid sectioning protocol integrates into the discovery-to-preclinical continuum, enabling timely hypothesis testing and target validation in human tissue models.
- Discovery Biology: Accelerates hypothesis-driven studies of protein localization and tissue susceptibility to infection.
- Screening: Delivers assay-ready sections for quantitative immunohistochemical readouts.
- Analytics: Supports robust measurement of protein markers (e.g., ACE2, TMPRSS2, Furin) across conditions.
- Translational Research: Bridges human tissue analysis with preclinical model findings for biomarker alignment.
- Enterprise Reuse: Establishes a scalable, rapid tissue preparation capability for future infectious disease research.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in tissue-based target validation and mechanistic studies.
- Operational Value: Standardizes and accelerates tissue processing, reducing resource and time burdens.
- Strategic Value: Enables faster go/no-go decisions in urgent research scenarios, improving capital efficiency.
- Portfolio Impact: Supports risk-adjusted prioritization of translational projects during public health emergencies.
Implementation Considerations
- Requires expertise in postmortem tissue handling and sectioning instrumentation.
- Demands access to precision microsaws with diamond blades and decalcification infrastructure.
- Necessitates cross-team standardization of tissue processing and staining protocols.
- Adaptable to various tissue types and protein targets with protocol optimization.
- Dependent on timely autopsy access and specimen quality for optimal results.
