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Published on: May 14, 2020
Arteriolar reactivity in lymphocyte-deficient mice
Sean Leonard1, B Anne Croy, Coral L Murrant
1Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
Summary
Lymphocytes, including T and natural killer (NK) cells, influence blood vessel tone. Their presence affects microvascular reactivity, with NK cells generally promoting constriction and other lymphocytes
Area of Science:
- Immunology
- Cardiovascular Physiology
- Microcirculation Research
Background:
- Growing evidence indicates lymphocytes regulate systemic circulatory control.
- The specific roles of T and natural killer (NK) cells in basal microvascular tone remain unclear.
Purpose of the Study:
- To investigate the influence of T and NK cells on microvascular arteriolar reactivity in physiologically normal conditions.
- To determine how lymphocyte populations affect responses to vasoconstrictors and vasodilators.
Main Methods:
- In situ intravital microscopy of mouse cremaster vasculature.
- Assessment of arteriolar reactivity to angiotensin II, phenylephrine, acetylcholine, and adenosine.
- Comparison between wild-type and genetically immunodeficient mice (lacking T, B, or NK cells).
Main Results:
- Immunodeficient mice exhibited smaller baseline and maximal arteriolar diameters.
- Lymphocytes generally promoted vasodilation at baseline, with exceptions noted for BALB/c NK cells.
- NK cells suppressed vasodilation to adenosine and acetylcholine, while T and B cells' effects varied with stimulus.
Conclusions:
- Lymphocytes, including T and NK cells, exert significant physiological influence on microvascular arteriolar reactivity.
- NK cells tend to promote vasoconstriction, while T and B cell effects are stimulus-dependent.
- These findings highlight the immune system's role in cardiovascular regulation.
