Annexin-1 as a salivary biomarker for gingivitis during pregnancy

Background: It is well established that there is higher susceptibility to gingival inflammation during pregnancy. Annexin-1 (ANXA1) is an anti-inflammatory protein which has been identified in gingival tissue exudates by discovery proteomics. This cross-sectional case-control study investigated the levels and association of ANXA1 and pro-inflammatory mediator interleukin (IL)-1β in the saliva of pregnant and non-pregnant women.

Methods: Whole unstimulated saliva from 69 non-pregnant and 78 pregnant women was collected prior to measurement of probing depth, clinical attachment level, bleeding on probing, and plaque. Then, the women were split into 3 subgroups depending on their periodontal status (healthy, gingivitis, and periodontitis). The levels of ANXA1 and IL-1β were measured with enzyme-linked immunosorbent assay and reported as pg/mg after normalizing against the total protein levels.

Results: Significantly higher ANXA1 levels were exhibited in pregnant women with gingivitis compared with health (P < 0.05) and in pregnant women with gingivitis compared with the respective non-pregnant group (P < 0.0001). There was a significantly higher level of IL-1β in gingivitis than in health in pregnant women (P < 0.05) and significantly higher levels in periodontitis compared with health in non-pregnant women (P < 0.05). Looking at the IL-1 β:ANXA1 ratio, the non-pregnant periodontitis group displayed a significantly higher ratio compared with the respective pregnant group (P < 0.05). In the non-pregnant subpopulation, the ratio was significantly higher in periodontitis compared with health (P < 0.01).

Conclusion: Salivary ANXA1 levels are elevated in the presence of gingivitis only in pregnant, but not non-pregnant women, rendering this molecule as a potential salivary biomarker for non-invasive early screening for gingival inflammation during pregnancy.