HAMP and open-angle glaucoma: In this respect, it is notable that TM cells respond to mechanical stress by upregulating TGF-β1 and IL-6,21 cytokines known to upregulate hepcidin,17,22,23 and the limited but noticeable protection of retinal ganglion cells by iron chelators suggests a prominent role of iron in the pathogenesis of POAG.24