In line with this, a hypoxic microenvironment combined with the presence of lipopolysaccharide (LPS) from P. gingivalis -a keystone periodontopathogen in periodontitis- induce the translocation of HIF-1α into the nucleus, which then dimerizes with HIF-1β, up-regulating the transcription of VEGF in human periodontal ligament and gingival fibroblast cells [110,111,112]. Here, VEGFA is linked to periodontitis.