PLG and diabetes mellitus: Golub et al. first demonstrated inhibition of MMPs by tetracyclines in people with diabetes.[14,17,32] The decision to use doxycycline in this study was based on these data, its broad spectrum MMPI[9,12,13], and its successful MMPI in a number of pathological states[16] including an animal model of diabetes.[9] The literature provides additional evidence that doxycycline can inhibit the activity of other classes of proteases such as plasmin (a serine protease)[33], and act as an oxygen radical scavenger.[34] Doxycycline is also known to be relatively well tolerated with minor side-effects.