A diet rich in omega-3 fatty acid improves periodontitis and tissue destruction by MMP2- and MMP9-linked inflammation in a murine model.

Periodontitis is an oral-cavity inflammatory disease and is the principal cause associated with tooth loss. Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are important proteases involved in periodontal tissue destruction. The omega-3 polyunsaturated fatty acids (ω-3 PUFA) have been demonstrated to possess immunoregulatory properties in periodontitis. The aim of the study was to investigate the effects of ω-3 PUFA on inflammation and on the expression of MMP-2 and -9 in a murine periodontitis model. Twenty-four male C57BL/6 mice were divided into control mice (Control), control mice treated with ω-3 PUFA (O3), mice with periodontitis (P), and mice with periodontitis treated with ω-3 PUFA (P + O3). ω-3 PUFA were administered orally once a day for 70 days. Periodontitis in mice was induced by Porphyromonas gingivalis-infected ligature placement around the second maxillary molar. The mice were sacrificed, and blood and maxillary samples were collected. Flow cytometry was used to quantify tumor necrosis factor-alpha (TNFα), interleukin (IL)-2, IL-4, IL-5, and interferon-gamma. Histologic analysis and immunohistochemistry for MMP-2 and -9 were performed. The data were statistically evaluated using analysis of variance (ANOVA) and the Tukey post hoc test. Histological analysis showed that ω-3 PUFA supplementation prevented inflammation and tissue destruction and revealed that bone destruction was more extensive in the P group than in the P + O3 group (p < 0.05). Also, it decreased the serum expressions of TNFα and IL-2 and the tissue expression of MMP-2 and -9 in the periodontitis-induced model (p < 0.05). ω-3 PUFA supplementation prevented alveolar bone loss and periodontal destruction, probably by decreasing the expression of MMP-2 and MMP-9 and its immunoregulatory properties.

Upregulation of proteins of the NLRP3 inflammasome in patients with periodontitis and uncontrolled type 2 diabetes.

OBJECTIVES: To evaluate the expression of proteins related to activation of the NLRP3 inflammasome in patients with chronic periodontitis (CP) and type 2 diabetes mellitus (T2D), and to determine whether the exacerbated periodontal pathological process observed in diabetic patients is related to its upregulation. MATERIALS AND METHODS: We performed an observational, analytical, cross-sectional study in three study groups: individuals systemically and orally healthy, and patients with CP with and without T2D. Gingival biopsies were taken from the three study groups. The expression of mRNAs for CASP1, NLRP3 and ASC was detected using real-time PCR, and the expression of NLRP3 and ASC proteins was determined by immunohistochemistry. The quantification of IL-18 and IL-1ß was determined in the gingival crevicular fluid using ELISA. The results were analysed by ANOVA followed by Tukey's test to compare differences between individual groups. RESULTS: Patients with CP and uncontrolled T2D presented severe periodontal disease and inflammation (PPD, p = 0.0072; CAL, p = 0.0480; bone loss, p = 0.0088), higher levels of CASP1 mRNA expression (p = 0.0026), a stronger pattern of staining for NLRP3 and ASC proteins in the epithelium and connective tissues, and significantly higher production of IL-18 (p = 0.0063) and IL-1ß (p = 0.0018) in comparison with healthy or CP subjects. CONCLUSION: The upregulation of genes and proteins involved in the activation of the NLRP3 inflammasome components in patients with periodontitis and uncontrolled T2D suggests a possible role in the more severe pathological processes leading to destruction of periodontal tissues observed in these patients.

Lipocalin-2 as a fundamental protein in type 2 diabetes and periodontitis in mice.

BACKGROUND: Lipocalin-2 (LCN-2) is an osteokine that suppresses appetite, stimulates insulin secretion, regulates bone remodeling, and is induced by proinflammatory cytokines. The aim of this work was to investigate the participation of LCN-2 in periodontitis associated with type 2 diabetes (T2D) by evaluating alveolar bone loss, glycemic control, inflammation, and femur fragility. METHODS: A murine model of periodontitis with T2D and elevated LCN-2 concentration was used. Functional LCN-2 inhibition was achieved using an anti-LCN-2 polyclonal antibody, and isotype immunoglobulin G was used as a control. The alveolar bone and femur were evaluated by micro-CT. Glucose metabolism was determined. Tumor necrosis factor (TNF-α) and receptor activator of nuclear factor kappa-B ligand (RANKL) levels in alveolar bone lysates were quantified using ELISA, and serum cytokines were quantified using flow cytometry. A three-point bending test was performed in the femur, and RANKL levels were measured in femur lysates using ELISA. RESULTS: Functional inhibition of LCN-2 in T2D-periodontitis mice decreased alveolar bone loss in buccal and palatal surfaces and preserved the microarchitecture of the remaining bone, decreased TNF-α and RANKL in alveolar bone, reduced hyperglycemia, glucose intolerance, and insulin resistance, and increased insulin production through improving the functionality of pancreatic ß cells. Furthermore, this inhibition increased serum free-glycerol levels, decreased serum interleukin (IL)-6, increased serum IL-4, and reduced femur fragility and RANKL expression in the femur. CONCLUSIONS: LCN-2 participates in periodontitis associated with T2D. Inhibiting its function in mice with T2D and periodontitis improves pancreatic ß-cell function, and glucose metabolism and decreases inflammatory cytokines and bone-RANKL levels, which results in the preservation of femoral and alveolar bone microarchitecture. PLAIN LANGUAGE SUMMARY: In this study, we explored the role of a bone protein known as lipocalin-2 (LCN-2) in the connection between periodontitis and type 2 diabetes (T2D). Periodontitis is a destructive gum and alveolar bone disease. LCN-2 levels are increased in both T2D and periodontitis. Using a mouse model of T2D with periodontitis, we examined how blocking LCN-2 function affected various aspects of these two diseases. We found that this inhibition led to significant improvements. First, it reduced alveolar bone loss and preserved bone structure by decreasing local inflammation and bone resorption. Second, it improved glucose and lipid metabolism, leading to better blood-sugar control and decreased insulin resistance. Blocking the functions of LCN-2 also decreased systemic inflammation throughout the body and strengthened bone integrity. Overall, our results suggest that LCN-2 plays a crucial role in the periodontitis associated with T2D. By inhibiting LCN-2 function, we were able to improve pancreatic function, improve glucose metabolism, reduce inflammation, and enhance bone health. Targeting LCN-2 could be a promising strategy for the harmful effects of T2D and periodontitis.

Bone Marrow as a Therapeutic Target for Type 2 Diabetes Complications.

Type 2 diabetes mellitus (T2DM) is a world epidemic with a high prevalence and mortality. The origin of macro and microvascular complications associated with T2DM is complex and new mechanisms to explain their development are emerging. The changes induced by T2DM in the microenvironment of bone marrow (BM) alter the expansion and differentiation of stem cells and have been related to the development of micro and macrovascular diseases. Alterations in the differentiation and function of hematopoietic, endothelial, and mesenchymal stem cells in T2DM patients reduced the mobility of BM stem cells to the circulation and some immature, dysfunctional, or inflammatory cells pass to the blood (mobilopathy). Consequently, tissue repair is impaired, and the tissue damage caused by hyperglycemia, oxidative stress, and inflammation is increased. These alterations can contribute to diabetic complications, decreasing the quality of life, and increasing mortality. The modulation of the bone marrow microenvironment may be a therapeutic target for treating T2DM and its complications. This article analyses the changes induced in BM and their impact on the development of cardiovascular and kidney complications in T2DM. Also, different therapeutic strategies to restore the bone marrow microenvironment and function through the modulation of oxidative stress, inflammation, and adipogenicity are discussed, considering bone marrow as a novel potential therapeutic target to treat vascular complications of diabetes.

Docosahexaenoic acid improves altered mineralization proteins, the decreased quality of hydroxyapatite crystals and suppresses oxidative stress induced by high glucose.

Patients with type 2 diabetes mellitus (DM2) experience an increased risk of fractures and a variety of bone pathologies, such as osteoporosis. The suggested mechanisms of increased fracture risk in DM2 include chronic hyperglycaemia, which provokes oxidative stress, alters bone matrix, and decreases the quality of hydroxyapatite crystals. Docosahexaenoic acid (DHA), an omega-3 fatty acid, can increase bone formation, reduce bone loss, and it possesses antioxidant/anti-inflammatory properties. The present study aimed to determine the effect of DHA on altered osteoblast mineralisation and increased reactive oxygen species (ROS) induced by high glucose concentrations. A human osteoblast cell line was treated with 5.5 mM glucose (NG) or 24 mM glucose (HG), alone or in combination with 10 or 20 µM DHA. The collagen type 1 (Col1) scaffold, the expression of osteocalcin (OCN) and bone sialoprotein type-II (BSP-II), the alkaline phosphatase (ALP) specific activity, the mineral quality, the production of ROS and the mRNA expression of nuclear factor erythroid 2-related factor-2 (NRF2) were analysed. Osteoblasts cultured in HG and treated with either DHA concentration displayed an improved distribution of the Col1 scaffold, increased OCN and BSP-II expression, increased NRF2 mRNA, decreased ALP activity, carbonate substitution and reduced ROS production compared with osteoblasts cultured in HG alone. DHA counteracts the adverse effects of HG on bone mineral matrix quality and reduces oxidative stress, possibly by increasing the expression of NRF2.

Aerobic training improves bone fragility by reducing the inflammatory microenvironment in bone tissue in type 2 diabetes.

Aerobic training (AT) is indicated in type 2 diabetes mellitus (T2DM) to control hyperglycaemia and inflammation. AT improves bone microarchitecture and resistance to fracture. The intensity of AT and the mechanisms that lead to the improvement in bone quality are still unknown. Using a mouse model of T2DM, we evaluated the effects of two intensities of forced AT. We divided mice into: sedentary (SED), T2DM-SED, low runners (LOW), T2DM-LOW, high runners (HIGH) and T2DM-HIGH. The AT for low was 8 m/minute (m/min); 5° slope or high 18 m/min; 15° slope for 2 months. We measured metabolic parameters, the serum cytokines concentration, lipocalin-2 (LCN-2) and adiponectin; and the tibial concentrations of LCN-2, tumour necrosis factor alpha (TNF-α) and protein carbonylation (CO). We evaluated femur morphometry and biomechanical properties. We performed multiple correlation analysis. The T2DM-LOW versus T2DM-SED group, shown an increase of interleukin (IL)-10 (417 ± 90 vs 102 ± 25 pg/mL) and improved trabecular bone (BV/TV: 31.8 ± 2.3 vs 19.25 ± 1.4%; Tb.Sp.: 1.62 ± 0.02 vs 2.0 ± 0.07 mm), by a decrease bone CO (3.4 ± 0.1 vs 6.0 ± 0.5 nmol/mg), bone TNF-α (84 ± 4 vs 239 ± 13 pg/mL) and LCN-2 (2887 ± 23 vs 3418 ± 105 pg/mL). The T2DM-HIGH versus T2DM-SED group showed a greater hypoglycaemic effect (228 ± 10 vs 408 ± 5 mg/dL), with improved cortical bone density (0.26 ± 0.012 vs 0.21 ± 0.007 mm) and fracture resistance (102 ± 8 vs 78 ± 5 MPa), by a reduction of bone TNF-α (77 ± 34 vs 239 ± 13 pg/mL); LCN-2 (2768 ± 20 vs 3418 ± 105 pg/mL) and CO (4.8 ± 0.5 vs 6.0 ± 0.5 nmol/mg). In conclusion, AT improves bone morphometry and biomechanical properties by reducing the bone inflammatory microenvironment.

Clinical applications of molecular basis for craniosynostosis: a narrative review / Aplicaciones clínicas de las bases moleculares de la craneosinostosis: revisión narrativa

Abstract: cranial sutures are specialized structures composed of the sutural mesenchyme, the overlying scalp, the dura and osteogenic fronts. Each one of these structures express important proteins for osteogenic maturation, membranous ossification of skull bones, and homeostasis of cranial sutures in a differential, spatial and temporal manner. These proteins include fibroblast growth factor (FGF) and its receptors (FGFR), the transforming growth factor beta (TGF-beta), bone morphogenetic proteins (BMPs), as well as transcription factors TWIST and MSX2, among others. The alteration in the expression of one or more of these proteins causes multiple pathological conditions; one of them is the premature closure of one or more cranial sutures, known as craniosynostosis. This malformation is commonly treated with surgery. However, advances in the fields of molecular and cellular biology have allowed to conduct research on some proteins involved in the development of craniosynostosis. The results of these studies can lead to future preventive therapeutic strategies that may be used as a complement to the surgical treatment of craniosynostosis. Possible strategies include the use of specific drugs that can regulate the expression and activation of FGF signaling pathways, TGF-beta or BMPs, to prevent or avoid craniosynostosis or re-synostosis after a surgery.

Resumen: las suturas craneales son estructuras especializadas compuestas por el mesénquima sutural, el pericráneo suprayacente, la duramadre y los frentes osteogénicos. Cada una de estas estructuras expresan de forma diferencial, espacial y temporalmente, proteínas importantes para la maduración osteogénica, la osificación membranosa de los huesos calvarios y la homeostasis de las suturas craneales. Estas proteínas incluyen el factor de crecimiento fibroblástico (FGF) y sus receptores (FGFR), el factor de crecimiento transformante beta (TGF-beta), las proteínas morfogenéticas óseas (BMPs), así como factores de transcripción TWIST y MSX2, entre otros. La alteración en la expresión de una o varias de estas proteínas provoca múltiples condiciones patológicas, una de ellas es el cierre prematuro de una o varias suturas craneales, conocido como craneosinostosis. Esta malformación es comúnmente tratada con cirugía. Sin embargo, los avances en los campos de la biología molecular y celular han permitido investigar algunas proteínas que participan en el desarrollo de la craneosinostosis. Los resultados de estos estudios pueden generar futuras estrategias terapéuticas preventivas o que complementen los tratamientos quirúrgicos de la craneosinostosis. Algunas estrategias posibles son el uso de fármacos específicos que puedan regular la expresión y activación de las vías de señalización del FGF, el TGFbeta o de las BMPs, para prevenir la craneosinostosis o evitar la resinostosis tras una cirugía.