The etiological consideration of oxidized low-density lipoprotein in periodontitis

Curcumin administration mitigates periodontitis-induced tissue damage in hypercholesterolemic rats: a natural preventive approach

This study investigated the preventive effect of curcumin (CUR) on tooth-supporting structures in hypercholesterolemic (HC) rats with periodontitis (P). Wistar rats (8 weeks old) (n = 30) were assigned to six groups based on dietary intake, CUR-piperine combination treatment and P induction. P was induced in four groups using a ligature model. Serum lipid profiles, oxidative stress parameters, radiographic, histological and histomorphometric analyses were performed. HC rats showed elevated serum cholesterol levels (p < 0.001). Moreover, topical administration of CUR did not regulate hypercholesterolemia in this model. The HC diet increased oxidative stress in gingival tissue, exacerbated by P, whereas CUR attenuated reactive species generation (p < 0.001) and reduced catalase (CAT) activity, possibly due to its antioxidant properties. Histological analysis revealed extensive erosive surfaces and osteoclast presence in the P groups, with the HC + P group showing the highest rate of bone resorption. The CUR-treated groups showed less bone resorption and more bone formation, indicating a protective effect. Histomorphometric studies showed a significant increase in bone volume in the CUR groups compared to the P groups (p < 0.001). CUR prevented bone resorption induced by P and HC diet, with larger osteoblastic surfaces and fewer osteoclasts, suggesting inhibition of bone resorption. CUR also prevented collagen fiber destruction caused by the HC diet. Overall, the study suggests a potential therapeutic role for CUR in mitigating periodontal tissue damage associated with hypercholesterolemia and P, due to its antioxidant and anti-inflammatory properties. Further research would be needed to validate its clinical efficacy as an adjunctive treatment for P.

Effects of oxidized LDL versus IL-1ß/TNF-ɑ/INFɣ on human gingival mesenchymal stem cells properties

AIMS

Oxidized low-density lipoprotein (oxLDL) is an important player in the course of metabolic inflammatory diseases. oxLDL was identified in the gingival crevicular fluid, denoting possible associations between oxLDL-induced inflammation and periodontal disease. The current investigation compared for the first-time direct effects of oxLDL to a cytokine cocktail of IL-1ß/TNF-ɑ/INF-γ on gingival mesenchymal stem cells' (G-MSCs) attributes.

METHODS

Human third passage G-MSCs, isolated from connective tissue biopsies (n = 5) and characterized, were stimulated in three groups over 7 days: control group, cytokine group (IL-1β[1 ng/mL], TNF-α[10 ng/mL], IFN-γ[100 ng/mL]), or oxLDL group (oxLDL [50 μg/mL]). Next Generation Sequencing and KEGG pathway enrichment analysis, stemness gene expression (NANOG/SOX2/OCT4A), cellular proliferation, colony-formation, multilinear potential, and altered intracellular pathways were investigated via histochemistry, next-generation sequencing, and RT-qPCR.

RESULTS

G-MSCs exhibited all mesenchymal stem cells' characteristics. oxLDL group and cytokine group displayed no disparities in their stemness markers (p > .05). Next-generation-sequencing revealed altered expression of the TXNIP gene in response to oxLDL treatment compared with controls (p = .04). Following an initial boosting for up to 5 days by inflammatory stimuli, over 14 day, cellular counts [median count ×10-5 (Q25/Q75)] were utmost in control - [2.6607 (2.0804/4.5357)], followed by cytokine - [0.0433 (0.0026/1.4215)] and significantly lowered in the oxLDL group [0.0274 (0.0023/0.7290); p = .0047]. Osteogenic differentiation [median relative Ca2+ content(Q25/Q75)] was significantly lower in cytokine - [0.0066 (0.0052/0.0105)] compared to oxLDL - [0.0144 (0.0108/0.0216)] (p = .0133), with no differences notable for chondrogenic and adipogenic differentiation (p > .05).

CONCLUSIONS

Within the current investigation's limitations, in contrast to cytokine-mediated inflammation, G-MSCs appear to be minimally responsive to oxLDL-mediated metabolic inflammation, with little negative effect on their differentiation attributes and significantly reduced cellular proliferation.

Oral biosciences: The annual review 2023

BACKGROUND

The Journal of Oral Biosciences is dedicated to advancing and disseminating fundamental knowledge with regard to every aspect of oral biosciences. This review features review articles in the fields of "bone regeneration," "periodontitis," "periodontal diseases," "salivary glands," "sleep bruxism," and "Sjögren's syndrome."

HIGHLIGHT

This review focuses on human demineralized dentin and cementum matrices for bone regeneration, oxidized low-density lipoprotein in periodontal disease and systemic conditions, the relationship between inflammatory mediators in migraine and periodontitis, phosphoinositide signaling molecules in the salivary glands, and the pathophysiologies of sleep bruxism and Sjögren's syndrome.

CONCLUSION

The review articles featured in the Journal of Oral Biosciences have broadened the knowledge of readers regarding various aspects of oral biosciences. The current editorial review discusses the findings and significance of these review articles.