Quantitative Determination of Hyaluronan Content in Cerebral Aneurysms by Digital Densitometry

OBJECT: Hyaluronan (HA) is a highly hydrated macromolecule; it is one of the essential components of the extracellular matrix (ECM) of the arteries and plays an important role in maintaining the biomechanical features of blood vessels. Although the potential contribution of HA in aneurysms of different vessels has been studied intensively, no data are available about the alteration of the HA content in the extracellular matrix of intracranial aneurysms. The aim of the study was to determine the hyaluronan content in the wall of human cerebral arteries. METHODS: A biotinylated aggrecan fragment that binds specifically to HA was used to stain samples from cerebral aneurysms (n = 11) to compare the HA content to non-aneurysmal arteries of patients who had intracranial aneurysm (n = 11), and to histologically normal arteries of patients who had expired from non-vascular diseases (n = 14). Digital microscopic densitometry was used for the quantitative analysis of the hyaluronan content in these samples. RESULTS: The highest level (169.5 +/- 7.9) was detected in aneurysms, while the HA-level of non-aneurysmal vessels was lower (130.2 +/- 16.8). Both vessel groups contained significantly higher HA than the normal cerebral arteries (32.9 +/- 2.1). CONCLUSIONS: Results suggest that an elevated hyaluronan level in the extracellular matrix may affect the cerebral arterial wall architecture. It is reasonable to suppose that the increased hyaluronan content creates a viscoelastic ECM which might improve the biomechanical resistance of the thinned vessel wall.