Increased levels of S100A12 and activated matrix metalloproteinase 2/9 (MMP-2/9) produced by human aortic smooth muscle cells (HASMCs) have recently implicated in the development of thoracic aortic disease.
Focus was placed on the aorta, since aortic disease is life threatening in the Marfan syndrome and fibrillin-1 green fluorescence was most abundant in this tissue.
Furthermore, SMCs cannot generate force without connections to the extracellular matrix through focal adhesions, and mutations in the major protein in the extracellular matrix, fibrillin-1, linking SMCs to the matrix also cause thoracic aortic disease in individuals with Marfan syndrome.
We determined signs of descending aortic disease before disease onset in mice with a mutation in the fibrillin 1 gene (Fbn1(+/C1039G)), a validated mouse model of disease susceptibility and progression of aortic aneurysm of MFS.
This study shows that common genetic variants at 15q21.1 that probably act via FBN1 are associated with STAAD, suggesting a common pathogenesis of aortic disease in Marfan syndrome and STAAD.
In the probands with aortic diseases in young who cannot be diagnosed with MFS, mutations other than FBN1 mutations accounted for at least one-third of all causes of aortic disease.
Aortic smooth muscle contains limiting amounts of myosin light chain kinase (MLCK) for myosin regulatory light chain (RLC) phosphorylation and contraction that predisposes to thoracic aortic disease in humans containing heterozygous loss-of-function mutations in MYLK.
Movement of the myosin motor domain is controlled by phosphorylation of the regulatory light chain on the myosin filament, and loss-of-function mutations in the dedicated kinase for this phosphorylation, myosin light chain kinase (MYLK) also predispose to thoracic aortic disease.
We sought to characterize the aortic disease and the presence of other vascular abnormalities in FTAAD caused by a deletion in MYLK and to compare thoracic aortic diameter and stiffness in mutation carriers and non-carriers.
To assess how LOX mutations modify protein function and lead to aortic disease, we studied the factors that influence the onset and progression of vascular aneurysms in mice bearing a Lox mutation (p.M292R) linked to aortic dilation in humans.
These data suggest that a missense mutation in LOX is associated with aortic disease in humans, likely through insufficient cross-linking of elastin and collagen in the aortic wall.
These data, along with previous studies showing that the deficiency of LOX in mice or inhibition of lysyl oxidases in turkeys and rats causes aortic dissections, support the conclusion that rare genetic variants in LOX predispose to thoracic aortic disease.
LDS type 4 is caused by mutations in TGFβ ligand 2 (TGFB2) and based on the family pedigrees described to date, appears to have a milder clinical phenotype, often presenting with isolated aortic disease.
These data suggest that a missense mutation in LOX is associated with aortic disease in humans, likely through insufficient cross-linking of elastin and collagen in the aortic wall.
Aortic disease, management, and outcome associated with the first aortic event (aortic dissection or aneurysm repair) were abstracted from the medical records of 277 individuals with 41 various ACTA2 mutations.
As the resulting protein is unlikely functional and by considering data from the literature, we support the notion that functional haploinsufficiency for TGF-β2 predisposes to thoracic aortic disease.