Donor MHC and adhesion molecules in transplant arteriosclerosis

Area of Science:

• Immunology
• Transplantation Biology
• Vascular Biology

Background:

• Transplant-associated arteriosclerosis (TAA) is a major cause of long-term graft failure.
• The role of donor-derived molecules in TAA pathogenesis is not fully understood.
• Molecules like MHC and adhesion molecules are critical in immune responses and cell interactions.

Purpose of the Study:

• To investigate the contribution of donor vasculature-expressed MHC and adhesion molecules to TAA.
• To elucidate the specific roles of MHC I, MHC II, P-selectin, and ICAM-1 in TAA development.

Main Methods:

• Carotid artery allografts from mutant mice deficient in specific molecules were transplanted into immunocompetent recipients.
• Mice strains included deficiencies in MHC I, MHC II, both MHC I and II, P-selectin, and ICAM-1.
• Neointima formation and cellular infiltration (CD4+ T cells, alpha-actin+ SMCs) were quantified.

Main Results:

• Absence of ICAM-1, MHC II, or both MHC I/II in donor arteries reduced neointima formation by 52%, 33%, and 38%, respectively, mainly by decreasing smooth muscle cell (SMC) accumulation.
• P-selectin deficiency did not alter neointima formation; combined P-selectin and ICAM-1 deficiency showed similar results to ICAM-1 deficiency alone.
• MHC I deficiency in donor arteries increased neointima formation by 52%, accompanied by a 2.8-fold increase in CD4+ T cells and a twofold increase in alpha-actin+ SMCs.

Conclusions:

• Donor vessel wall ICAM-1 and MHC II molecules promote transplant-associated arteriosclerosis.
• Donor-derived MHC I molecules may exert a protective effect against TAA.
• Targeting these donor molecules could offer therapeutic strategies to improve graft survival.