Variance of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) concentrations in activated, concentrated platelets from healthy male donors.
BACKGROUND
The use of autologous blood concentrates, such as activated, concentrated platelets, in orthopaedic clinical applications has had mixed results. Research on this topic has focused on growth factors and cytokines, with little directed towards matrix metalloproteinases (MMPs) which are involved in post-wound tissue remodeling.


METHODS
In this study, the authors measured the levels of MMP-2, MMP-9 and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), in activated platelets derived from blood of healthy, male volunteers (n = 92), 19 to 60 years old. The levels of the natural inhibitors of these proteases, tissue inhibitor of metalloproteinase 1 (TIMP-1), TIMP-2 and TIMP-4 were also assessed.


RESULTS
Notably, there was no significant change in concentration with age in four of six targets tested. However, TIMP-2 and TIMP-4 demonstrated a statistically significant increase in concentration for subjects older than 30 years of age compared to those 30 years and younger (P = 0.04 and P = 0.04, respectively).


CONCLUSIONS
TIMP-2 and TIMP-4 are global inhibitors of MMPs, including MMP-2 (Gelatinase A). MMP-2 targets native collagens, gelatin and elastin to remodel the extracellular matrix during wound healing. A decreased availability of pharmacologically active MMP-2 may diminish the effectiveness of the use of activated, concentrated platelets from older patients, and may also contribute to longer healing times in this population.
Department of Orthopaedics and Rehabilitation, Dwight D, Eisenhower Army Medical Center, 300 Hospital Road, Fort, Gordon, GA 30905, USA. justin.m.hire.mil@mail.mil.
Justin M
JM
Hire
J Lee
JL
Evanson
Peter C
PC
Johnson
Steven D
SD
Zumbrun
M Kelly
MK
Guyton
James C
JC
McPherson
John A
JA
Bojescul
D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D001782:Blood Donors; D001792:Blood Platelets / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000097:blood*; D008875:Middle Aged; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000097:blood*; D019714:Tissue Inhibitor of Metalloproteinases / Q000097:blood*; D055815:Young Adult; D000097792:Tissue Inhibitor of Metalloproteinase-4
D015415:Biomarkers; D020778:Matrix Metalloproteinase 2; D019716:Tissue Inhibitor of Metalloproteinase-2; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4; C560823:TIMP2 protein, human; C522361:MMP2 protein, human