MMP9 and type 2 diabetes mellitus: MMP-9 protein was only detected by zymography in one ND-DF line (where it increased in a TNF-α concentration-dependent manner), yet it was readily detected in 3 out of the 4 T2DM-DF, where there was a suggestion that it may increase in a TNF-α concentration dependent manner, though this was not statistically significant (Fig. 4e-f).