Systematically transplanted human gingiva-derived mesenchymal stem cells regulate lipid metabolism and inflammation in hyperlipidemic mice with periodontitis.

Gingiva-derived mesenchymal stem cells (GMSCs) have been the focus of extensive research due to their numerous distinct properties, including their homing to injury sites and their contribution to tissue regeneration. However, the role of transplanted GMSCs in the regulation of lipid metabolism and inflammation in hyperlipidemic mice with periodontitis has not been demonstrated. In the present study, apolipoprotein E-deficient (ApoE-/-) mice were used to establish a hyperlipidemia model with periodontitis and divided into two groups: Group B and Group C (n=20 per group), and wild-type C57BL/6J mice without any treatment were assigned to Group A (n=20). Animals in Group C were then injected with human GMSCs through the tail vein and animals in Group B were injected with α-MEM as control. Animals were sacrificed at indicated time points. Serum was collected to determine the lipids and inflammatory cytokines. Liver samples were collected to estimate lipid-associated gene expression. Morphometric and histological analyses were performed to maxillaries. The results demonstrated that the delivery of GMSCs led to a significant decrease in triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL), interleukin (IL)-6, tumor necrosis factor (TNF)-α, alveolar bone loss (ABL), and sterol regulatory element binding protein-1c (SREBP-1c) mRNA, and a significant increase in high density lipoprotein cholesterol (HDL), IL-10 and peroxisome proliferator-activated receptor α (PPARα) mRNA in Group C compared to Group B. Histological examination showed increased formation of new bone and higher alveolar bone height in Group C. Systematically transplanted GFP-positive cells were detected through both fluorescence microscope observation and immunohistochemical staining in the periodontal tissues. Overall, systematically transplanted GMSCs attenuated the hyperlipidemia and inflammatory responses in hyperlipidemic mice with periodontitis, and improved periodontal tissue regeneration.

The treatment of systematically transplanted gingival mesenchymal stem cells in periodontitis in mice.

Cell-based tissue engineering is a promising alternative for periodontal regeneration as current therapies fail to reconstitute tissue damage caused by periodontitis. As newly identified postnatal stem cells, gingiva-derived mesenchymal stem cells (GMSCs) have been focused on for isolation and expansion in vitro of cells with multi-differentiation potential and immunomodulatory capacities. It has been demonstrated that systemically delivered GMSCs can home to the mandibular bone defect sites and promote bone regeneration. However, the role of transplanted GMSCs in the treatment of periodontitis has not been reported. In the present study, GMSCs were transplanted into C57BL/6J mice with periodontitis via the tail vein to investigate the contribution of GMSCs to periodontal tissue regeneration. Results demonstrated that the alveolar bone heights of mice with transplanted GMSCs were significantly increased compared with the control groups and GMSCs were detected in newly formed periodontal ligament and alveolar bone. The results of the present study implied that systemically transplanted GMSCs could home to periodontal injury sites and promote periodontal tissue regeneration.

Gingival mesenchymal stem cells attenuate pro-inflammatory macrophages stimulated with oxidized low-density lipoprotein and modulate lipid metabolism.

OBJECTIVE: To examine the effects of gingival mesenchymal stem cells (GMSCs) on inflammatory macrophages upon oxidized low-density lipoprotein (ox-LDL) stimulation and evaluate therapeutic potential of GMSCs on mouse model of periodontitis associated with hyperlipidemia. METHODS: in vitro, GMSCs were co-cultured with macrophages for 48 h in the absence or presence of M1 polarizing conditions and oxidized low-density lipoprotein in the transwell system. The supernatants were collected for ELISA. M1 and M2 markers of macrophages were analyzed by flow cytometry and PCR, and lipid accumulation was assessed by oil red O staining. in vivo, eighteen mice were divided into three groups (n = 6): Group A (periodontally healthy mice as control), Group B (periodontitis mice with hyperlipidemia), Group C (periodontitis mice with hyperlipidemia with the transplantation of GMSCs). The serum levels of cholesterol and inflammatory factors were measured by automatic analyzer. Bone regeneration was evaluated by Masson staining. RESULTS: When co-cultured with GMSCs, the M1 markers of Tumor Necrosis Factor (TNF) -α, Interleukin (IL) -6, Interleukin (IL) -1ß, CD86, and Human Leukocyte Antigen (HLA) -DR were significantly reduced. In contrast, M2 markers such as Interleukin(IL) -10 and CD206 were moderately increased. Similar results were obtained in the cell culture supernatants. In animal experiment, GMSCs suppressed the expression of sterol regulatory element binding transcription factor 1c (SREBP-1c) and elevated the levels of peroxisome proliferator-activated receptor alpha (PPARα) and peroxisome proliferator activator receptor- coactivator 1(PGC-1α) in the liver, attenuated cholesterol dysfunction via the downregulation of low-density lipoprotein (LDL) and total cholesterol (TC), and the upregulation of high-density lipoprotein (HDL), and decreased the levels of TNF-α and IL-6. Moreover, GMSC treatment improved bone regeneration. CONCLUSION: GMSCs inhibit the activation of M1 macrophages, regulate lipid metabolism and reduce inflammatory response, and promote bone regeneration in mouse model of periodontitis associated with hyperlipidemia.

An experimental hyperlipidemia model with periodontitis in mice.

PURPOSE: In many animal models and clinical trials, the relationship between periodontitis and hyperlipidemia is bidirectional and interlinked. In this study, an experimental hyperlipidemia model with periodontitis in mice is introduced. METHODS: C57BL/6J mice were assigned into group A and B and Apolipoprotein E-deficient (ApoE-/-) mice into group C. After 4 weeks of a high fat diet (HFD), group B and C were ligated on the maxillary second molar tooth, and mice were sacrificed after 8 weeks of the HFD. Levels of lipids, interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α in serum after 0, 4, and 8 weeks were determined. Alveolar bone loss (ABL) was assessed under stereomicroscope. Maxillary bones and atherosclerotic lesion area in the aorta were collected for hematoxylin and eosin (HE) staining. RESULTS: After feeding with a HFD for 4 weeks, group C demonstrated dramatic increases in serum lipid levels. The ABL and levels of IL-6, IL-10, and TNF-α in group C was significantly higher than those of group A and B (P<0.05). Atherosclerotic lesions were observed in group C. CONCLUSIONS: These data demonstrate that an experimental hyperlipidemia model with periodontitis in mice is successfully established by ligation in ApoE-/- mice. This method is economical and time saving, and worthy of more general application.