If you happen to be research minded and a little weird then this "CYTOKINES INFO PLAYGROUND" will satisfy all your cytokines info needs.
http://www.copewithcytokines.de/cope.cgi
http://www.copewithcytokines.de/cope.cgi?key=MMP%2d9
Check out this page on NGF -Nerve Growth Factor
http://www.copewithcytokines.de/cope.cgi?key=NGF
Note the fact good old reliable Vitamin D3 causes our brains to produce more NGF Nerve Growth Factor came as a real surprise to me. Vitamin D3 also lowers MMP-9s.
This "potent producer of NGF" is another reason to take a LOT of Vitamin D3.
jackD