Matrix Metalloproteinases in Abdominal Aortic Aneurysm: Characterization, Purification, And Their Possible Sources

Abstract

One of the most consistent observations in abdominal aortic aneurysm (AAA) disease is the disorganization and disruption of elastin and other matrix components of the aortic wall. The enzymatic basis for the biochemical features of AAA has been investigated beginning with the demonstration on substrate gel enzymography of a typical "profile" of proteinase activities in AAA tissue extracts which degrade gelatin, casein and elastin. A recombinant TIMP-1 affinity column was developed and three of the elastolytic/caseinolytic activities with approximate molecular weights of approximately 80 kDa, approximately 50 kDa and approximately 32 kDa were partially purified from these extracts. Affinity for rTIMP-1 suggests that these enzymes are members of the matrix metalloproteinase (MMP) family. High molecular weight forms of two MMPs, collagenase (MMP-1) and stromelysin-1 (MMP-3), were also isolated from the AAA tissue on this column; active forms of MMP-1 could be demonstrated by immunoblotting techniques in this preparation under reducing conditions. Infiltrating inflammatory cells are known sources of these proteolytic activities; analysis of these cell populations in the aneurysmal aortic wall using fluorescence-activated cell counting revealed a fifty-fold increase in macrophages (a well-known source of matrix-degrading enzymes) as well as a significant increase in lymphocytes.

Identification of matrix metalloproteinases 3 (stromelysin-1) and 9 (gelatinase B) in abdominal aortic aneurysm.

“…The presence of MMP-1 in aneurysmal aorta has not been firmly established. 8 ' 1315 We have observed forms consistent with known active forms of MMP-1 in AAA tissue extracts using specific antibody, 17 and increased amounts of immunoreactive material to MMP-1 are present in AAA compared with control specimens. 36 The possible presence of active forms of MMP-3 and a serine proteinase suggests a cascade of events leading to activated forms of both MMP-1 and MMP-9 that could then lead to the concerted degradation of elastin, fibrillar collagens, and other ECM components in the vascular wall during aneurysm development and progression.…”

“…On casein zymography, major bands of activity were seen at 80, 50, and 32 kD. 17 While minor activity was observed at 80 kD in extracts from control aortas, this activity was not purified on the rTIMP-1 affinity column. The gelatinolytic/caseinolytic activities at 80, 50, and 32 kD purified on the rTIMP-1 affinity column were further isolated by electroelution from an SDS-polyacrylamide gel under nonreducing conditions.…”

“…815 We have described a prominent metalloproteinase activity with an apparent molecular weight of 80 kD present in aneurysmal tissue, 16 and we have developed techniques for isolating it and several other activities (at 50 and 32 kD) for further characterization. 17 Specific identification of the observed proteinases is an important first step in determining their involvement in AAA development. In this article we demonstrate an increase in forms of MMP-3 and MMP-9 in extracts of AAA tissue and show that the major component of the previously described 80-kD activity is MMP-9.…”

“…The individual activities at 80, 50, and 32 kD were electroeluted from the areas of the gel corresponding to the appropriate molecular weight. 17 In addition, the protein from the high-molecular-weight region of the gel (>97 kD) was electroeluted. The electroeluted proteins were concentrated by using Centricon-10 concentration units (Amicon).…”

Vascular pathology in hereditary connective tissue disorders

“…Один из механизмов деградации матрикса Ао, вероятно, обусловлен активацией металлопротеиназ матрикса, участвующих в разрушении коллагена и других молекул экстрацеллюлярного матрикса. Активация металлопро-теиназ может быть связана с мутацией, приводящей к повышению активности тканевого плазминогенного активатора, превращающего плазминоген в активный плазмин, влияющий на активность металлопротеиназ матрикса [23]. САБА в 3 раза чаще встречается у муж-чин, по сравнению с женщинами, преимущественно после 50 лет [24].…”