HIF1A and periodontal disorder: Toker et al. [53] presented results which indicated that grape seed proanthocyanidin extract (GSPE) can substantially decrease periodontal tissue inflammatory process and alveolar bone loss by decreasing MMP-8 and hypoxia-inducible factor 1-alpha (HIF-1-α) levels and increase osteoblast activity in diabetic rats with experimentally induced periodontal disease (Table 2).