Immunohistochemical study of morphology and distribution of CD163+ve macrophages in the normal adult equine gastrointestinal tract.

The research article focuses on the study of the presence and distribution of macrophages, a crucial part of our immune system, within the gastrointestinal tract of horses. This was achieved by using the CD163 marker, a specific identifier for these macrophages, in tissue samples from multiple areas of the equine gastrointestinal tract.

Objective of Study

• The main aim of the study was to identify the location and abundance of resident macrophages (a type of white blood cell that can fortify immune responses) within the gastrointestinal tract of horses. This was carried out using CD163 as an immunohistochemical marker.
• These macrophages play a critical role in maintaining equilibrium in the intestines, participating in immune responses and also interacting with the nervous system of the intestinal tract.

Methodology

• Tissue samples were obtained post-mortem from 14 different sites along the gastrointestinal tracts of 10 horses that were free from gastrointestinal disease.
• The tissue samples ranged from various parts of the tract, starting from the stomach to the small colon.

Findings

• The presence of CD163 cells (macrophages) was found throughout the entirety of the gastrointestinal tract in all horses, from the stomach to the small colon.
• The macrophages were also located in all the different tissue layers of the intestinal wall – mucosa, submucosa, muscularis externa (ME), myenteric plexus, and serosa.
• Specifically within the muscularis externa, the macrophages were uniformly distributed, with dense accumulation linked closely with the myenteric plexus and effector cells, such as neurons and the interstitial cells of Cajal (ICC). This supports the proposed function of these macrophages in managing intestinal motility.

Implications

• This study adds to the limited research available on equine intestinal macrophages, providing further insight into their distribution and possible role within the gastrointestinal tract.
• The results of this research could frame the development of potential therapeutic interventions targeting these cells, especially in relation to gastrointestinal diseases in horses.