Dr. Todor et al., IDENTIFICATION OF A SERUM GELATINASE ASSOCIATED WITH THE OCCURRENCE OF CEREBRAL ANEURYSMS AS PRO-MATRIX METALLOPROTEINASE-2, Stroke, 29(8), 1998, pp. 1580-1583
Background and Purpose-Subarachnoid hemorrhage from intracranial aneur
ysm rupture produces a severe form of stroke. Extracellular matrix rem
odeling is associated with cerebral aneurysms and may play a role in t
he formation or rupture of these lesions. We previously reported a 3-f
old increase in a 72-kDa serum gelatinase in a subgroup of aneurysm pa
tients. The purpose of the present study was to further characterize a
nd identify this gelatinase. Methods-Serum samples were collected from
surgical patients with intracranial aneurysms. The following series o
f experiments was designed to further characterize and identify the pr
edominant serum gelatinase found in the subgroup of patients with incr
eased gelatinase activity. Gelatin zymography was performed on native
serum samples and compared with serum that had been pretreated with a
known metalloproteinase activator (4-aminophenylmercuric acetate [APMA
]). Gelatin zymography was repeated in the presence of a matrix metall
oproteinase (MMP) inhibitor (EDTA) and a serine proteinase inhibitor (
phenylmethylsulfonyl fluoride [PMSF]). Final identification was made b
y Western blotting with the use of monoclonal antibodies to MMP-2 and
MMP-9. Results-A consistent gelatinolytic band (72 kDa) was identified
in all serum samples (n=60). Pretreatment of the serum by APMA (n=60)
lowered the molecular weight of the band to 66 kDa. The band was inhi
bited by EDTA (n=10) but not PMSF (n=10), thus characterizing the circ
ulating 72-kDa gelatinase as an inactive pro-MMP. Western blotting (n=
20) identified the 72-kDa band as MMP-2. Conclusions-These findings co
nfirm that the increased gelatinolytic activity observed in vitro in a
subset of cerebral aneurysm patients is due to pro-MMP-2.