Fixation on Histology

2023 NSH Poster Winners Brought Exciting Research to the NSH Convention

  

Each year NSH features a robust poster program at its annual convention.  This past week during the 2023 Annual Convention in Baltimore, NSH featured 38 incredible posters that all provided interesting information, scientific data, and breakthroughs in the field of histotechnology.  While each poster offered its own unique value, three winning posters were selected by the NSH Convention Poster Team.  Winning posters were selected not only for their outstanding content but their ability to effectively communicate using the poster format.   Take a look at the poster abstracts from this year’s selected winners. 

P-31: Alternative Strategies For Analyzing Pre-Clinical Mouse Lungs   

Nicholas Pankow, BA1,2; Gabriela De La Cruz, BS1,2; Hannah Atkins, PhD, DVM3, University of North Carolina at Chapel Hill, 2Lineberger Comprehensive Cancer Center, 3Department of Pathology & Laboratory Medicine 

In some diseases or conditions, it is challenging to leverage human tissues to determine patterns and resolve disease progression. Similarities between human and mouse biology make using murine models in pre-clinical studies possible. More specifically, mouse lungs are used to further analyze respiratory illnesses as they provide scalable models that can either be genetically manipulated to elicit human diseases or follow similar phenotypic outcomes. Mice are thus used in several different disease models that can be later translated to human conditions including asthma, COPD, toxicants, cystic fibrosis, as well as viral and bacterial infections. The standard histological embedding orientation of the lung provides an easy view of the main bronchus, alveoli, bronchioles, trachea, and related lymph nodes for distinct research inquiries. However, the standard histological orientation may not demonstrate the specific areas of interest to further investigate these conditions. By trimming the lung lobes in specific ways or altering the orientation during embedding, we can provide a specific focus to a study. One alternative embedding strategy is the “max airway”, which focuses on showing the main bronchus anatomy on all lung lobes. The “morphometry” embedding strategy allows for multiple cross-sections of the left lung lobe and a cross-section of the main airway. Another common method is the “lung sampling” strategy which provides a systematically chosen cross-section of the lungs. A “left lobe focus” strategy is used to review the bronchioles and alveolar areas. Finally, “whole lung” embedding can be useful for examining general lung morphology, adjacent mediastinal structures, and other organs. Using these different protocols, we can bring a desired focus to a study and have a more scalable experiment without using human tissue early in the process. 
P-02: Evaluation of Hormones Secreted by Pancreatic Endocrine Tumors as Assessed by Immunohistochemistry   

Anne Mones and Sheila Criswell, University of Tennessee Health Science Center 

The endocrine component of the pancreas is localized primarily in the islets of Langerhans but also appears as single cells among the acinar cells and ductal epithelium. It is currently thought that endocrine tumors of the pancreas (PETs) arise from pluripotent stem cells among the ductal epithelium rather than from existing endocrine cells. Islet cell components include alpha, beta, PP, delta, and epsilon cells which secrete glucagon, insulin, pancreatic polypeptide, somatostatin, and ghrelin, respectively. This study investigated the degree of staining of 24 PETs to identify which hormones were most frequently produced. Glucagon was found to be the most frequently secreted hormone (83%) in PETS followed by insulin, ghrelin, pancreatic polypeptide, and somatostatin. 

 

P-29: Comparison of Dorsal Root Ganglia Collection in Adult Mice for Histologic Evaluation.  

Laura Monarski, Timothy Coskran, and Xavier Palazzi Global Pathology, Pfizer Inc. Drug Safety Research and Development, Groton, CT 

Preclinical gene therapy and targeted protein degrader studies have shown neurotoxicity in dorsal root ganglia (DRG) and paravertebral ganglia (PG) along with other toxicities in multiple species, including mouse. This has created a need for specialized tissue collection and evaluation. This experiment compared resource time demand, quality of hematoxylin and eosin stained DRG, and effects of decalcification on immunohistochemistry of two collection methods. Mouse DRG were collected post-fixation, through partial laminectomy using a stereoscope and microdissection tools. The entire spinal column was collected intact (viscera and limbs removed) and placed in 10% neutral buffered formalin (NBF) for two days. The dorsal aspect of the vertebral column was removed and bilateral pairs of DRG and nerve root were individually dissected from each vertebral region (cervical, thoracic, and lumbar), placed in tissue cassettes, and processed to paraffin block. This tedious process requires extensive training and is time consuming. An alternative method to sample DRG in situ was explored by collecting transverse sections from the spinal column using razor blades. This method removed the need for partial laminectomy and dissection of DRG from the column. After one day in NBF, transverse sections of spinal column were trimmed from cervical, thoracic, and lumbar regions, decalcified, and processed to paraffin block. In general, the in-situ collection method takes less time to collect samples, avoids the microdissection step, but requires more microtomy time to produce satisfactory sections containing bilateral DRG. H&E staining quality was comparable between methods and decalcification of soft tissue did not adversely affect IHC for antibodies evaluated in this experiment. The dissection method requires extensive training time to build the needed expertise to collect DRG. With a good understanding of the vertebral column anatomy, and careful trimming, the in-situ method could be a suitable alternative method for collecting and evaluating mouse DRG. 

 

If you attended the convention this year, be sure to check them out in the virtual platform or on the app!  


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