Background: Over-expression of hyaluronan (HA), glycosaminoglycan found in the extracellular matrix, results in the stiffening of the arterial wall by thinning of elastic lamellae in animal models. However, the effect in human arteries is more contentious. We aimed to study the relationship between serum HA and aortic stiffness in a cohort of healthy subjects.

Methods: Subjects were randomly selected from the Anglo-Cardiff Collaborative Trial (ACCT) database. Subjects underwent detailed haemodynamic assessment, including measurements of blood pressure (BP) and aortic pulse wave velocity (aPWV) (SphygmoCor, AtCor, Australia). Serum HA levels were measured by commercially available ELISA kit (DY3614, R&D Systems, U.K).

Results: 155 individuals (73 females and 82 males), with a mean age of 44±19 years, and a mean of BP of 134±16/86±11 mmHg were studied. HA and aPWV both increased with aging (P<0.0001 for both see the figure). Subjects were then split into tertiles of serum HA. aPWV was positively associated with HA tertile (7.03±1.42 v. 7.57±1.69 v. 8.10±2.00 m/s P=0.002). In multiple regression analysis, we found that HA remained independently associated with aPWV after adjusting for mean arterial pressure, BMI and gender (model R²=0.233,P<0.001).

Conclusions: Our data suggests that hyaluronan may be one of the factors behind age-related aortic stiffening. However, further studies are needed to establish whether this association is causal and to understand the mechanism behind it.