Vascular-associated lymphoid tissue in swine (Sus scrofa)

Area of Science:

• Cardiovascular Research
• Immunology
• Animal Models

Background:

• Human arteries exhibit focal mononuclear cell accumulations at atherosclerosis-prone sites, termed vascular-associated lymphoid tissue (VALT).
• Pigs are a widely used animal model for cardiovascular disease research.

Purpose of the Study:

• To investigate the presence and characteristics of VALT in pigs (Sus scrofa).
• To determine if pig VALT structures resemble those found in human arteries.
• To assess the relevance of pig VALT in the context of atherosclerosis development.

Main Methods:

• Collection and processing of major artery samples from conventional crossbred pigs.
• Application of light microscopy, immunohistochemistry, and immunofluorescence techniques.
• Analysis of cellular composition (T cells, macrophages) and molecular markers (MHC class II) in arterial tissues.

Main Results:

• Focal aggregates of mononuclear cells, primarily CD3+CD4+ T cells and macrophages, were identified in pig arteries at branching sites.
• These aggregates expressed major histocompatibility class II molecules on infiltrating leukocytes and endothelial cells.
• Similar leukocytic aggregates were observed in Ossabaw pigs at sites predisposed to atherosclerosis, with decreased lymphocyte density in pigs on an atherogenic diet.

Conclusions:

• Pigs exhibit vascular-associated lymphoid tissue (VALT) structures in their arteries, analogous to those in humans.
• The presence of VALT in pigs reinforces their utility as a preclinical model for human cardiovascular diseases.
• Further research into pig VALT may elucidate mechanisms underlying atherosclerosis and inform therapeutic strategies.