Thoracic aortic aneurysms are life-threatening vascular conditions linked to inherited disorders such as Marfan syndrome, Loeys–Dietz syndrome, vascular Ehlers–Danlos syndrome, and familial thoracic aortic aneurysms and dissections. While traditionally associated with the extracellular matrix and contractile defects in vascular smooth muscle cells, emerging evidence suggests the key role of mitochondrial dysfunction. Here, we show that the overexpression of ACTA2^R179H and TGFBR2^G357W in murine aortic VSMCs reduces Mitochondrial Transcription Factor A (Tfam) expression, decreases mitochondrial DNA (mtDNA) content, and impairs oxidative phosphorylation, shifting metabolism toward glycolysis. Notably, nicotinamide riboside, a NAD⁺ precursor, restores mitochondrial respiration, increases Tfam and mtDNA levels, and promotes a contractile phenotype by enhancing actin polymerization and reducing matrix metalloproteinase activity. These findings identify mitochondrial dysfunction as a shared feature in hereditary thoracic aortic aneurysm, not only in Marfan syndrome, but also in other genetic forms, and highlight mitochondrial boosters as a potential therapeutic strategy.

This study presents the effect of gamma rays of up to 2000 kGy on the chemical structure and the physical properties of a poly(butylene adipate-co-terephthalate) (PBAT) with 48% mol of terephthalic units. PBAT is a polymer with properties similar to polyethylene (PE) but it is biodegradable and not toxic to the environment, and it can be prepared with a renewable content of up to 68.6% weight, with uses in biomedicine and packaging. Previous studies found in the literature have been conducted using low doses and the results were contradictory. The results for gel content and crosslinking efficiency were in agreement with the results found in the literature. Molecular weight decreased and widened with the increase in dose. Proton NMR analysis was used for the first time in PBAT to determine the changes in chemical species, the formation of new chemical species, and the bonds more susceptible to be broken by gamma rays. Both thermal and mechanical properties were explained by the scission of the chains in the amorphous phase and at the boundaries of the crystallites. The thermal parameters most affected by irradiation were the crystallization temperature and temperature of melting after cooling from the melt. Stress and strain at break suffered a continuous decrease with dose until PBAT became fragile at high dose.

This study presents the effect of gamma rays of up to 2000 kGy on the chemical structure and the physical properties of a poly(butylene terephthalate) (PBT). PBT is an important engineering polymer, tougher than PET, that can be upgraded by radiation crosslinking with the addition of crosslinkers. Previous studies found in the literature provided very limited data about the effect of ionizing radiation on pure PBT. No gel was produced, and the changes in molecular weight with the increase in dose were in agreement with the results found in the literature, with a decrease until 1000 kGy dose when chain scission predominated and a slight increase at higher doses when crosslinking became significant. Proton NMR analysis was used for the first time in PBT to determine the changes in chemical species, mainly the appearance of terminal butyl groups and aromatic carboxylic groups coming from the rupture of the ester linkage. Both thermal and mechanical properties were explained by the scission of the chains in the amorphous phase and at the boundaries of the crystallites, and the crosslinking in the amorphous phase. The thermal parameter most affected by irradiation was the crystallization temperature, which increased when chain scission was predominant up to a 1000 kGy dose and decreased at higher doses when crosslinking became significant. Stress and strain at break suffered a continuous decrease with dose until PBT became fragile at high dose, with a faster decrease in strain at break from the 1000 kGy dose, when crosslinking became significant.