Concentration of plasma AGEs is significantly higher in hypertensive than in normotensive subjects and related to aortic stiffness independent of age and blood pressure, with no relationship with aortic wave reflection. Plasma AGEs may play a blood pressure-independent role in large but not small vessel remodeling in essential hypertension.

Although arterial stiffness is an independent cardiovascular risk factor associated with both aging and hypertension, relatively little is known regarding the structural changes in the vessel wall that occur with vessel stiffening. We determined if collagen type-I metabolism is related to arterial stiffening in both hypertensive and normotensive subjects. Arterial stiffness was assessed by aortic pulse wave velocity (PWV) and augmentation index (AIx) in 46 subjects (48.772 years, 32 hypertensives) and related to circulating markers of collagen type-I turnover. Collagen synthesis was assessed by the measurement of carboxy-terminal peptide of procollagen type-I (PIP) and collagen degradation by the measurement of carboxy-terminal telopeptide of collagen type-I (ICTP), by quantitative immunoassay. Matrix metalloproteinase-1 (MMP-1) and the tissue inhibitor of metalloproteinase-1 (TIMP-1) were also quantified by immunoassay. The ratio of collagen type-I synthesis to degradation was negatively correlated with both PWV (Po0.05) and AIx (Po0.05), whereas plasma MMP-1 levels displayed a positive correlation with both PWV (Po0.01) and AIx (Po0.01), after adjustment for age and mean arterial pressure. The relationship between collagen type-I turnover and arterial stiffness was similar in both the normotensive and hypertensive subjects. Although circulating markers of collagen synthesis were increased in the hypertensive subjects, this was not related to arterial stiffness. Collagen type-I degradation is increased in relation to collagen type-I synthesis in subjects with stiffer arteries. Matrix metalloproteinase-1, the enzyme responsible for collagen type-I degradation, is positively related to both large elastic and muscular artery stiffness in normotensive and hypertensive subjects.

This study demonstrates that age-related MMP-2 upregulation occurs in the human aorta but not in the IMA.

Mongersen is a 21-mer antisense oligonucleotide designed to downregulate Mothers against decapentaplegic homolog 7 (SMAD7) expression to treat Crohn's disease. Mongersen was manufactured in numerous batches at different scales during several years of clinical development, which all appeared identical, using common physicochemical analytical techniques, while only phosphorous-31 nuclear magnetic resonance ( 31 P-NMR) in solution showed marked differences. Close-up analysis of 27 mongersen batches revealed marked differences in SMAD7 downregulation in a cell-based assay. Principal component analysis of 31 P-NMR profiles showed strong correlation with SMAD7 downregulation and, therefore, with pharmacological efficacy in vitro . Mongersen contains 20 phosphorothioate (PS) linkages, whose chirality (Rp/Sp) was not controlled during manufacturing. A different diastereomeric composition throughout batches would lead to superimposable analytical data, but to distinct 31 P-NMR profiles, as indeed we found. We tentatively suggest that this may be the origin of different biological activity. As similar manifolds are expected for other PS-based oligonucleotides, the protocol described here provides a general method to identify PS chirality issues and a chemometric tool to score each preparation for this elusive feature.

Background Age-related changes in arterial stiffness are ascribed to collagen and elastin content in the aorta (Ao) which is modulated by the matrix metalloprotienases (MMPs). However, no study has directly compared arterial stiffness and arterial structure in man. Methods Aortic and internal mammary artery (IMA) tissue were obtained from 10 patients (62±1 years, 2 female) undergoing coronary artery bypass grafting (CABG). Aortic pulse wave velocity (PWV) was measured prior to CABG. Collagen content was assessed in tissue sections using Sirius Red staining and elastin by ACCUSTAIN. Elastin fragmentation in the Ao media was graded; increasing in severity from 1 to 4. MMP-2 and MMP-9 activity was quantified in the Ao using gelatine zymography. Results are expressed as mean±SEM, p<0.05 considered significant. Results The collagen concentration was 50% (intima), 42% (media)and 76% (adventitia) in the Ao but was lower in the IMA. PWV was significantly associated with Ao medial (r=0.79, p=0.03) but not intimal or adventitial collagen concentrations. Aortic intimal thickness was related significantly with age (r=0.70, p<0.05) but not PWV. There was no relationship between age and Ao collagen concentration. There was a significant association (p<0.001) between increasing elastin fragmentation in the aortic media and PWV but not age. There was no relationship between collagen concentration in the IMA and either PWV or age. Neither latent nor active MMP-2 activity was related with PWV or age. Latent MMP-9 expression was significantly associated with PWV (r=0.66, p<0.05) but not age. Conclusions Our proof-of-concept study is the first one to show that elastin fragmentation in the aorta may underlie arterial stiffening in man. In contrast, the internal mammary artery does not age, unlike the aorta, which makes it the reassuring choice for coronary artery bypass grafting. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Health Research Board, Ireland