TY - JOUR
T1 - Plasma storage at -80°C does not protect matrix metalloproteinase-9 from degradation
AU - Rouy, Didier
AU - Ernens, Isabelle
AU - Jeanty, Céline
AU - Wagner, Daniel R.
N1 - Funding Information:
This work was supported by grants from the CRP-Santé, Luxembourg. The authors thank Malou Glossener and Loredana Jacobs for expert research assistance and Dr. Susanne Michel for helpful corrections of the manuscript.
PY - 2005/3/15
Y1 - 2005/3/15
N2 - Recently, matrix metalloproteinase-9 (MMP-9) has been identified as a cardiovascular risk marker and is increasingly being determined in clinical studies. Among other matrix metalloproteinases, MMP-9 is known to be self-activable, as the cleavage of the propeptide leads to the formation of an active enzyme. In such a case the issue of storage of biological samples such as plasmas is of outstanding importance, as an enzymatic activity, although minimal, may remain at common storage temperature, i.e., -80°C. Since 2000 our institute has created a plasma library from patients presenting with acute myocardial infarction. Recently, the evaluation of the MMP-9 led to the surprise of finding a dramatically low level of detectable enzyme in the oldest plasma samples. By using zymography, enzyme-linked immunosorbent assay and Western blots, we evaluated new and old samples and found that MMP-9 degrades over time. After 2 years, the detectable total MMP-9 dropped by 65%, and the asymptotic profile of the curve reached a residual 1% level after 43 months. These results were confirmed by zymography and western blotting. TIMP-1, the natural inhibitor of MMP-9 and MMP-2, remained rather stable over time. The results suggest that human plasma MMP-9 levels should be determined as soon as possible after sampling.
AB - Recently, matrix metalloproteinase-9 (MMP-9) has been identified as a cardiovascular risk marker and is increasingly being determined in clinical studies. Among other matrix metalloproteinases, MMP-9 is known to be self-activable, as the cleavage of the propeptide leads to the formation of an active enzyme. In such a case the issue of storage of biological samples such as plasmas is of outstanding importance, as an enzymatic activity, although minimal, may remain at common storage temperature, i.e., -80°C. Since 2000 our institute has created a plasma library from patients presenting with acute myocardial infarction. Recently, the evaluation of the MMP-9 led to the surprise of finding a dramatically low level of detectable enzyme in the oldest plasma samples. By using zymography, enzyme-linked immunosorbent assay and Western blots, we evaluated new and old samples and found that MMP-9 degrades over time. After 2 years, the detectable total MMP-9 dropped by 65%, and the asymptotic profile of the curve reached a residual 1% level after 43 months. These results were confirmed by zymography and western blotting. TIMP-1, the natural inhibitor of MMP-9 and MMP-2, remained rather stable over time. The results suggest that human plasma MMP-9 levels should be determined as soon as possible after sampling.
KW - Enzyme
KW - Matrix metalloproteinase
KW - Plasma storage
UR - http://www.scopus.com/inward/record.url?scp=14644426471&partnerID=8YFLogxK
UR - https://pubmed.ncbi.nlm.nih.gov/15745750
U2 - 10.1016/j.ab.2004.10.052
DO - 10.1016/j.ab.2004.10.052
M3 - Article
C2 - 15745750
AN - SCOPUS:14644426471
SN - 0003-2697
VL - 338
SP - 294
EP - 298
JO - Analytical Biochemistry
JF - Analytical Biochemistry
IS - 2
ER -