Deficiency of total collagen content and of deoxypyridinoline in intracranial aneurysm walls

The tissue contents of total collagen and of 3-hydroxypyridinium cross-links, pyridinoline (PYD) and deoxypyridinoline (DPD), were measured in 15 samples of human aneurysms of Willis' Circle obtained at surgery and in 25 autopsy control samples of intracranial arteries of Willis' Circle obtained from 6 subjects who died of other causes than cerebral hemorrhage. PYD and DPD were detected fluorimetrically after HPLC separation. Total collagen content was significantly lower (P <0.001) in aneurysm samples (mean ± S.E.M. 2.50 ± 0.33 nmol of α 1(I) collagen chain per mg of delipidated and dried material) than in controls (mean ± S.E.M. 3.86 ± 0.14). DPD, but not PYD, content appears to be lower in aneurysm walls. In the aneurysms, the tissue contents of PYD ranged from 212 to 587 pmol/nmol of α 1(I) collagen chain (mean ± S.E.M. 430 ± 31) while in control samples the values observed ranged from 292 to 642 (mean ± S.E.M. 471 ± 21). The tissue content of DPD was measurable only in 6 aneurysm samples (60%), ranging from 12 to 60 pmol/nmol of α 1(I) collagen chain (mean ± S.E.M. 33 ± 9), while in control samples, DPD content ranged from 30 to 123 (mean ± S.E,M. 75 ± 5).