Generalized gingivitis-related salivary proteomic profile in pregnant women with obesity: insights into biological mechanisms assessed by Tandem Mass Spectrometry

Abstract

Aim: This cross-sectional study investigated the salivary proteomic profile associated with generalized gingivitis in pregnant women with obesity.

Methodology: Pregnant women in the third trimester (≥27 weeks of gestation) were divided into two groups based on bleeding on probing (BOP): G1 (BOP>50%; n=9) and G2 (BOP 0-30%; n=9). Collected unstimulated saliva samples were individually analyzed using nano liquid chromatography electron spray ionization tandem mass spectrometry. Identified proteins were classified according to gene ontology for biological processes, molecular functions, immune system involvement, and cellular components. Differential protein expression was determined using thresholds of p<0.05 for downregulation and 1-p>0.95 for up-regulation proteins.

Results: Of the 183 identified proteins, 100 were shared between groups, totaling 57 up-regulated and 27 downregulated proteins in G1. Key biological processes included antimicrobial humoral response and hydrogen peroxide catabolism, with proteins linked to immune function and endopeptidase regulation. Functional analysis showed that Lactotransferrin (5-fold increase in G1), Haptoglobin (4-fold), and Immunoglobulin J chain (3-fold) were up-regulated, whereas Statherin (5-fold) and Protein S100-A8 (4-fold) were downregulated in G1.

Conclusions: Pregnant women with obesity and generalized gingivitis exhibited a distinct salivary proteomic profile characterized by the up-regulation of immune-related proteins and downregulation of tissue-protective proteins. These findings suggest potential salivary biomarkers for detection and targeted management of periodontal inflammation in this high-risk population.

Graphical abstract

Figure 1. Venn diagram showing common proteins between G1 and G2 samples (including both up- and downregulated proteins in G1), and the number of proteins uniquely identified in each group.

Figure 2. Functional analysis comparing G1 and G2. Differential expression patterns varied across categories, with both up-regulated and downregulated proteins in G1 compared with G2. (A) Biological Processes highlighting the antimicrobial humoral response and the hydrogen peroxide catabolic process. (B) Immune System Processes emphasizing the antimicrobial humoral response and complement activation. (C) Cellular Component analysis showing predominant categories like the immunoglobulin complex, circulating and the NuA4 histone acetyltransferase complex. (D) Molecular Function analysis highlighting cysteine-type endopeptidase inhibitor activity.

Figure 3. Interaction network of up- and downregulated proteins in G1 compared with G2 (changes >2-fold), highlighting functional categories and associated proteins. Blue nodes represent proteins linked to the defense response to bacteria; red and pink nodes indicate proteins involved in antibacterial and antimicrobial humoral responses, respectively; and green nodes highlight proteins associated with endopeptidase regulation. Acronyms shown in the figure correspond to gene symbols for each protein, which are detailed in Tables 2 and 3.