A pancreatic venular defect in the BB/Wor rat

Area of Science:

• Immunology
• Endocrinology
• Pathology

Background:

• Spontaneous autoimmune diabetes mellitus in BB rats involves insulitis, an inflammatory infiltrate of pancreatic islets.
• The role of pancreatic vascular endothelium in this autoimmune process remains unclear.

Purpose of the Study:

• To investigate the involvement of pancreatic vascular endothelium in the development of autoimmune diabetes in BB rats.
• To identify specific vascular defects in diabetes-prone (DP) BB rats compared to diabetes-resistant (DR) BB rats and other rat strains.

Main Methods:

• Injection of Monastral blue B, a colloidal pigment, to identify leaky microvasculature in the pancreas.
• Light and electron microscopy to examine vascular structures and cellular infiltration.

Main Results:

• Evidence of a venular defect, specific to the pancreas, was observed exclusively in BB rats.
• This defect appears to be caused by intravascular monocytes adhering to the venular walls.
• Monastral blue B may activate these trapped monocytes, leading to the release of vasoactive mediators.

Conclusions:

• A unique pancreatic venular defect exists in BB rats, potentially contributing to insulitis and autoimmune diabetes.
• Trapped intravascular monocytes in pancreatic venules are implicated in this defect.
• Further research into these vascular abnormalities could offer new therapeutic targets for diabetes.