STUDY THE RELATIONSHIP BETWEEN OSTEOPROTEGERIN AND KIDNEY INJURY MOLECULE-1 AND SOME BIOCHEMICAL VARIABLES IN PATIENTS WITH KIDNEY STONES.

Kidney stones are a common disorder that affects men and women. Stones are hard, abnormal deposits that form inside the kidneys. They are also known as kidney stones or urinary stones. The incidence of kidney stones has increased significantly, and their prevalence is increasing worldwide. Osteoprotegerin (OPG) is a biochemical variable that plays an important regulatory role in predicting various kidney diseases. KIM-1 also known as HAVcr-1, and TIM-1 is a sensitive and specific biomarker for kidney injury due to its great importance. United States of America, Food and Drug Administration, and European Medicines Agency have adopted KIM-1 as a biomarker in urine to detect kidney injuries.

Mapping RANKL- and OPG-expressing cells in bone tissue: the bone surface cells as activators of osteoclastogenesis and promoters of the denosumab rebound effect.

Denosumab is a monoclonal anti-RANKL antibody that inhibits bone resorption, increases bone mass, and reduces fracture risk. Denosumab discontinuation causes an extensive wave of rebound resorption, but the cellular mechanisms remain poorly characterized. We utilized in situ hybridization (ISH) as a direct approach to identify the cells that activate osteoclastogenesis through the RANKL/OPG pathway. ISH was performed across species, skeletal sites, and following recombinant OPG (OPG:Fc) and parathyroid hormone 1-34 (PTH) treatment of mice. OPG:Fc treatment in mice induced an increased expression of RANKL mRNA mainly in trabecular, but not endocortical bone surface cells. Additionally, a decreased expression of OPG mRNA was detected in bone surface cells and osteocytes of both compartments. A similar but more pronounced effect on RANKL and OPG expression was seen one hour after PTH treatment. These findings suggest that bone surface cells and osteocytes conjointly regulate the activation of osteoclastogenesis, and that OPG:Fc treatment induces a local accumulation of osteoclastogenic activation sites, ready to recruit and activate osteoclasts upon treatment discontinuation. Analysis of publicly available single-cell RNA sequencing (scRNAseq) data from murine bone marrow stromal cells revealed that Tnfsf11+ cells expressed high levels of Mmp13, Limch1, and Wif1, confirming their osteoprogenitor status. ISH confirmed co-expression of Mmp13 and Tnfsf11 in bone surface cells of both vehicle- and OPG:Fc-treated mice. Under physiological conditions of human/mouse bone, RANKL is expressed mainly by osteoprogenitors proximate to the osteoclasts, while OPG is expressed mainly by osteocytes and bone-forming osteoblasts.

Analysis of angiotensin II type 1 receptor and osteoprotegerin gene polymorphism on the risk of cardiovascular mortality risk and progressivity of chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is a significant global public health issue with increased risk of atherosclerotic cardiovascular disease (ASCVD) and cardiovascular mortality. Single nucleotide polymorphisms (SNPs) on angiotensin II type 1 receptor (AT1R) A1166C and osteoprotegerin (OPG) C950T gene have received significant attention as a genetic risk factor for cardiovascular disease and CKD. METHODS: This was a cross-sectional study involving 75 adults with CKD recruited from Nephrology Outpatient Clinics of Universitas Airlangga Hospital, Surabaya, Indonesia. Demographic data was obtained from interviews and medical records. The "CKD Patch" application was used to asses ASCVD and cardiovascular mortality risk scores. Statistical analysis was performed by using SPSS version 26. RESULTS: We detected four different AT1R gene polymorphisms (A1166C, A1160C, G1170T, and G1181C) and two OPG gene polymorphisms (T950C and G1181C) in Indonesian CKD patients. A1160C and G1181C polymorphisms were novel SNPs, newly discovered in this research. No significant association was found between AT1R SNPs and kidney prognostic markers or ASCVD risk/mortality risk scores. However, for OPG C950T we found that TT genotype had a significantly higher ACR than TC or CC genotype (P=0.032). As for OPG G1181C, we found that GG genotype had a higher serum creatinine and albumin to creatinine ratio compared to GC and CC genotypes (P=0.004 and 0.029, respectively). Genotype GC for OPG G1181C was also shown to be protective for having better kidney markers and lowest cardiovascular mortality risk compared to GG and CC genotypes (P=0.018 and 0.032, respectively). CONCLUSIONS: Increased ASCVD risk and mortality risk score was not found on individuals with AT1R gene SNPs. However, for OPG gene polymorphism, C950T and G1181C were associated with kidney progression and cardiovascular mortality.

Vertebral marrow fat fraction is associated with circulating RANKL in postmenopausal females.

Objective: To investigate the relationship between circulating receptor activator of nuclear factor-kappa B ligand (RANKL) levels and marrow adipose tissue in postmenopausal females. Methods: A total of 164 postmenopausal females were included in the study. Serum levels of osteoprotegerin (OPG) and RANKL were measured using ELISA kits. Body composition and bone mineral density (BMD) were assessed using dual-energy X-ray absorptiometry. Complex-based chemical shift imaging-based MRI was employed to evaluate the vertebral marrow proton density fat fraction (PDFF). A multivariate linear regression model was utilized to analyze the predictive effects of PDFF and BMD on circulating levels of OPG and RANKL. Results: Simple regression analysis showed significant associations among the marrow PDFF, BMD at either site, serum RANKL, and the RANKL/OPG ratio. In multivariate linear regression models, marrow PDFF was found to have a positive correlation (ß = 3.15, 95% CI 2.60 to 3.70) and BMD had negative correlations (ß = -0.200, 95% CI -0.348 to -0.051 for vertebral BMD; ß = -0.383, 95% CI -0.589 to -0.177 for total hip BMD; and ß =-0.393, 95% CI -0.598 to -0.188 for femoral neck BMD, all p < 0.01) with circulating soluble RANKL levels after adjusting for age, body mass index, physical activity, total fat mass, android/gynoid ratio, and lean mass. Similar results were observed for the RANKL/OPG ratio. Additionally, multivariate linear regression analyses revealed that marrow PDFF was a significant independent contributor of circulating soluble RANKL (ß = 1.34, 95% CI 1.10 to 1.58, p < 0.001) after further controlling for BMD. However, marrow PDFF or BMD had no associations with circulating levels of OPG after adjusting for all potential confounders mentioned above. Conclusions: Vertebral marrow fat fraction is independently associated with circulating soluble RANKL levels in postmenopausal females.

Association of periodontitis with serum osteoprotegerin level in type 2 diabetic postmenopausal women.

OBJECTIVE: To evaluate the association of periodontitis with serum osteoprotegerin level according to glycaemic state in postmenopausal type 2 diabetic women. METHODS: The case-control study was conducted from June 2019 to May 2020 at the National Diabetes Centre, Mustansiriyah University, Baghdad, Iraq, and comprised postmenopausal diabetic women with good glycaemic control in group A, diabetic women with poor glycaemic control in group B, and non-diabetic healthy controls in group C. Participants were inducted by using the consecutive sampling technique. Assessment of periodontitis was done by measuring probing pocket depth, gingival recession and clinical attachment level. The ratio between serum osteoprotegerin level and glycated haemoglobin was calculated for all the subjects. Data was analysed using SPSS 24. RESULTS: Of the 150 subjects, 57(38%) were in group A with mean age 57.39±5.89 years, 43(28.7%) were in group B with mean age 58.91±4.95 years, and 50(33.3%) were in group C with mean age 54.92±4.62 years. Probing pocket depth, clinical attachment level and serum osteoprotegerin exhibited higher values in groups A and B compared to group C, and in group B compared to group A (p<0.001). There was a significant positive correlation between Probing pocket depth and serum osteoprotegerin in all groups (p<0.05). CONCLUSIONS: Periodontal parameters and serum osteoprotegerin level were significantly higher in diabetic women, especially in those with poor glycaemic control, than in healthy controls, and serum osteoprotegerin level showed a significant positive correlation with probing pocket depth in all the studied groups.

Strontium ranelate modulates circular RNA BACH1/microRNA-155-5p to ameliorate root resorption and tooth anchoring during orthodontic tooth movement.

The tooth movement is a fundamental requirement during any orthodontic treatment. This study aimed to investigate the action and mechanism of strontium ranelate (SR) in orthodontic tooth movement (OTM). Rats were given SR by gavage daily, along with lentiviral vectors interfering with circBACH1 or miR-155-5p. Three weeks later, an OTM rat model was established. RANKL and osteoprotegerin (OpG) in serum were measured. The gap between the first and second molar and root resorption were examined. Osteoclast test was used; and root condition was examined. Detection of miR-155-5p, circBACH1, CLC7 and cathepsin K was performed. The binding of circBACH1 to miR-155-5p was verified. In OTM rats, circBACH1 was elevated (p<0.05) and miR-155-5p was silenced (p<0.05). SR reduced osteoclast activity (p<0.05) and improved root resorption (p<0.05) in OTM rats, which was enhanced by silenced circBACH1 (p<0.05) or elevated miR-155-5p (p<0.05). circBACH1 inhibited miR-155-5p expression (p<0.05). Silenced miR-155-5p reversed the ameliorative effect of circBACH1 on tooth root resorption in OTM rats (all p<0.05). SR modulates circBACH1/miR-155-5p to ameliorate root resorption and tooth fixation during OTM.

Impact of Freeze-dried Corticocancellous Bone Allograft Combined with Enamel Matrix Derivative in the Treatment of Critical-sized Calvarial Bone Defects: An Animal Study.

AIM: This study compared the quality and quantity of newly formed bone in rabbits' critical-sized calvarial defects filled with enamel matrix derivative (EMD) combined with freeze-dried bone allograft (FDBA) vs FDBA alone. MATERIALS AND METHODS: A total of 24 adult male white New Zealand rabbits were included. In each rabbit, three bone defects with a diameter of 8 mm were created on the calvarium bone; the first defect was left untreated, while the second was filled with FDBA, and the third was filled with EMD + FDBA. Twelve rabbits were randomly euthanized after a month, and the remaining 2 month postsurgery. Bone sections were histologically evaluated by hematoxylin and eosin and vascular endothelial growth factor (VEGF), alkaline phosphatase (ALP), osteoprotegerin (OPG), and receptor activator of NF-kappaB (RANK) immune-histochemical staining. RESULTS: An improvement in the newly formed bone percentage was found in the defects filled with EMD + FDBA in comparison with FDBA and control defects at 1 month and 2 months postsurgery. Additionally, the expression of VEGF, ALP, OPG, and RANK showed highly significant differences in the defects filled with EMD + FDBA compared to the FDBA and control ones at 1 month postsurgery (p = 0.001). Meanwhile, VEGF and ALP expression showed a significant decrease in defects filled with EMD + FDBA compared to the FDBA and control ones (p = 0.001), while OPG and RANK expression showed non-significant differences between treated groups at 2 months postsurgery. CONCLUSION: Enamel matrix derivative combined with FDBA has a synergistic effect on bone formation and graft substitution. This combination accelerates the expression of VEGF, ALP, OPG, and RANK. CLINICAL SIGNIFICANCE: The combination of EMD and FDBA accelerates and ameliorates the quality of newly formed bone, aiding in maxillofacial reconstruction. How to cite this article: Zakri RN, Grawish ME, Mowafey B, et al. Impact of Freeze-dried Corticocancellous Bone Allograft Combined with Enamel Matrix Derivative in the Treatment of Critical-sized Calvarial Bone Defects: An Animal Study. J Contemp Dent Pract 2024;25(5):424-431.

Interactions of the Osteokines, Glucose/Insulin System and Vascular Risk Networks in Patients With Newly Diagnosed Type 2 Diabetes (VNDS 15).

BACKGROUND AND AIM: Bone as an endocrine organ regulates metabolic processes independently of mineral metabolism through the production/release of proteins collectively named 'osteokines'. Relevant connections were reported between the insulin/glucose system, calcification of the atherosclerotic plaque, and several osteokines. We aimed to test the hypothesis that the osteokine network could be involved in beta-cell function, insulin sensitivity, and vascular damage in a cohort of people with newly diagnosed type 2 diabetes (T2D). SUBJECTS AND METHODS: In 794 drug-naive, GADA-negative, newly-diagnosed T2D patients (mean ± SD age: 59 ± 9.8 years; BMI: 29.3 ± 5.3 kg/m2; HbA1c: 6.6 ± 1.3%) we assessed: plasma concentration of osteocalcin (OCN), osteopontin (OPN), RANKL, and its putative decoy receptor osteoprotegerin (OPG); insulin sensitivity (SI) by hyperinsulinemic euglycemic clamp; beta cell function (BCF), estimated by OGTT minimal modelling and expressed as derivative (DC) and proportional (PC) control. Echo-doppler of carotid and lower limb arteries were also performed in 708 and 701 subjects, respectively. RESULTS: OCN, RANKL and OPG were significantly associated with PC (p < 0.02); OCN was positively related to DC (p = 0.018). OPG was associated with lower IS (p < 0.001). Finally, the higher RANKL levels, the greater was the severity of atherosclerosis in common carotid artery (p < 0.001). Increased OPG and OPN concentrations were related to subclinical atherosclerosis in peripheral arteries of lower limbs (p = 0.023 and p = 0.047, respectively). CONCLUSION: These data suggest that, in patients with newly diagnosed T2D, the osteokine network crosstalks with the glucose/insulin system and may play a role in modulating the atherosclerotic process.

RANK-RANKL-OPG Axis in MASLD: Current Evidence Linking Bone and Liver Diseases and Future Perspectives.

Metabolic dysfunction-associated steatotic liver disease (MASLD)-and its worse form, metabolic-associated steatohepatitis (MASH), characterised by inflammation and liver damage-corresponds to the liver's involvement in metabolic syndrome, which constitutes an economic burden for healthcare systems. However, the biomolecular pathways that contribute to steatotic liver disease are not completely clear. Abnormalities of bone metabolism are frequent in people affected by metabolic liver disease, with reduced bone density and an increased risk of fracture. Receptor activator of NF-κB (RANK), receptor activator of NF-κB ligand (RANKL), and osteoprotegerin(OPG) are critical regulators of bone metabolism, performing pleiotropic effects, and may have potential involvement in metabolic disorders like MASLD, resulting in a topic of great interest and intrigue. This narrative review aims to investigate this potential role and its implications in MASLD development and progression and in hepatocellular carcinoma, which represents its worst complication.

LEVELS OF OSTEOPROTEGERIN AND IRISIN IN POSTMENOPAUSAL OSTEOPOROSIS WOMEN.

BACKGROUND: Osteoporosis (OP) is a highly prevalent disorder affecting 50 million individuals around the world. It is also a typical skeletal disorder described by low bone mass, which leads to reduced bone strength and an enhanced risk of fractures. Osteoprotegerin As a member of the TNF receptor superfamily, osteoprotegerin is well recognized for its protective effect against excessive bone resorption. Irisin is Irisin is a muscle-secreted hormone that is generated by the cleavage of membrane protein FNDC-5 (fibronectin type III domain-containing protein 5) (FNDC5). Irisin is widely distributed in the human body and is involved in the browning of white adipose tissue, improving insulin resistance, improving cognitive function, and regulating bone metabolism. METHODS: This study was a prospective cross-sectional study involving 90 postmenopausal osteoporosis (PMOP) Iraqi women in Kirkuk City over one year time; from April 2023 to the end of July 2024. Sixty women with osteoporosis are diagnosed by DEXA. And 30 women as a control group. The blood samples were collected from each woman included in this study for the estimation of osteoprotegerin and irisin. Were measured using the ELISA kit. RESULT: This was conducted on sixty postmenopausal osteoporosis women. The age range was (50-65) years and the mean body mass index was (30.05) and thirty women as a control group. The age range was (50-65) years, and the mean body mass index was (27.55). The study found that the mean serum level of osteoprotegerin, increased in postmenopausal osteoporosis women compared to control (P-Value = 0.0007, while the mean serum level of irisin was lower in postmenopausal osteoporosis women compared to control this result was highly significant at a P value of 0.0004. CONCLUSION: This study reveals that there was a positive correlation between serum osteoprotegerin, level with irisin (R=0.175).

Vascular Cytokines and Atherosclerosis: Differential Serum Levels of TRAIL, IL-18, and OPG in Obstructive Coronary Artery Disease.

The risk-factor-based prediction of atherosclerotic coronary artery disease (CAD) remains suboptimal, particularly in the absence of any of the standard modifiable cardiovascular risk factors (SMuRFs), making the discovery of biomarkers that correlate with atherosclerosis burden critically important. We hypothesized that cytokines and receptors associated with inflammation in CAD-tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interleukin-18 (IL-18), and osteoprotegerin (OPG)-would be independently associated with CAD. To determine this, we measured the serum biomarker levels of 993 participants from the BioHEART study who had CT coronary angiograms that were scored for severity of stenosis and plaque composition. We found that the quartiles of TRAIL, OPG, and IL-18 were significantly associated with disease scores, and that the IL-18/TRAIL and OPG/TRAIL ratios demonstrated significant differences between no CAD vs. STEMI whereas only the OPG/TRAIL ratio showed differences between no CAD and obstructive CAD (stenosis > 50%). However, these associations did not persist after adjustment for age, sex, SMuRFs, and a family history of CAD. In conclusion, TRAIL, IL-18, and OPG and the derived ratios of IL-18/TRAIL and OPG/TRAIL demonstrate significant associations with raw disease scores and risk factors, but these markers are not discriminatory biomarkers for the prediction of CAD when incorporated into multi-variable risk models.

Serum proinflammatory cytokines, receptor activator of nuclear factor kappa-Β ligand (RANKL), osteoprotegerin (OPG) and RANKL/OPG ratio in mild and severe COVID-19.

INTRODUCTION: Osteoporosis, a systemic skeletal disease, is characterized by a quantitative and qualitative, and progressive decrease in bone mass, which is related to inflammation. Since a cytokine storm is triggered in Coronavirus disease 2019 (COVID-19), this study aims to evaluate pro-inflammatory cytokines (TNF-α, IL-1ß), Receptor activator of nuclear factor-κB ligand (RANKL)/serum osteoprotegerin (OPG) ratio, and their relationship in mild and severe COVID-19. METHODS: This study was performed on 48 adult patients (18 mild, 18 severe COVID-19, and 12 healthy subjects as a control group). Serum OPG, RANKL, TNF-α, IL-1ß, 25-OH vitamin D, and ALKp were measured by ELISA and colorimetric assay. RESULTS: COVID-19 patients had a significant increase in RANKL, and RANKL/OPG in mild and severe form (p < 0.001) while OPG decreased significantly in severe form compared to healthy controls (p < 0.05). Inflammatory cytokines (TNF-α and IL-1ß) increased in both groups of patients whereas Alkaline phosphatase (ALKp) increased only in severe patients (p < 0.001). Both groups had 25-OH vitamin D deficiency in comparison to healthy ones (p < 0.001). Pearson's correlation coefficient was performed to determine the relationship between RANKL, OPG, ALKp, and 25-OH vitamin D with TNF-α and IL-1ß in mild and severe COVID-19, which was statistically significant. CONCLUSION: Serum RANKL/OPG ratio was elevated in COVID-19 individuals and is assumed to be a risk factor for BMD reduction and osteoporosis in these patients. Correlations between IL-1ß, TNF-α, ALKp, 25-OH vitamin D, OPG, RANKL, and RANKL/OPG ratio offered the potential role of these proinflammatory markers in the mechanism of osteoporosis in COVID-19 patients.

Integrated bioinformatic analysis of protein landscape in gingival crevicular fluid unveils sequential bioprocess in orthodontic tooth movement.

BACKGROUND: The biological mechanisms driving orthodontic tooth movement (OTM) remain incompletely understood. Gingival crevicular fluid (GCF) is an important indicator of the periodontal bioprocess, providing valuable cues for probing the molecular mechanisms of OTM. METHODS: A rigorous review of the clinical studies over the past decade was conducted after registering the protocol with PROSPERO and adhering to inclusion criteria comprising human subjects, specified force magnitudes and force application modes. The thorough screening investigated differentially expressed proteins (DEPs) in GCF associated with OTM. Protein-protein interaction (PPI) analysis was carried out using the STRING database, followed by further refinement through Cytoscape to isolate top hub proteins. RESULTS: A comprehensive summarization of the OTM-related GCF studies was conducted, followed by an in-depth exploration of biomarkers within the GCF. We identified 13 DEPs, including ALP, IL-1ß, IL-6, Leptin, MMP-1, MMP-3, MMP-8, MMP-9, PGE2, TGF-ß1, TNF-α, OPG, RANKL. Bioinformatic analysis spotlighted the top 10 hub proteins and their interactions involved in OTM. Based on these findings, we have proposed a hypothetic diagram for the time-course bioprocess in OTM, which involves three phases containing sequential cellular and molecular components and their interplay network. CONCLUSIONS: This work has further improved our understanding to the bioprocess of OTM, suggesting biomarkers as potential modulating targets to enhance OTM, mitigate adverse effects and support real-time monitoring and personalized orthodontic cycles.

Nitrogen-containing bisphosphonate induces enhancement of OPG expression and inhibition of RANKL expression via inhibition of farnesyl pyrophosphate synthase to inhibit the osteogenic differentiation and calcification in vascular smooth muscle cells.

BACKGROUND: Nitrogen-containing bisphosphonate(N-BP)had been found to inhibit the osteogenic differentiation and calcification in vascular smooth muscle cells (VSMCs), but the mechanism is not clear. We intend to verify that N-BP induces enhancement of OPG expression and inhibition of RANKL expression via inhibition of farnesyl pyrophosphate synthase(FPPS) to inhibit the osteogenic differentiation and calcification in VSMCs. METHODS: ß-glycerophosphate (ß-GP) was used to induce the osteogenic differentiation and calcification in VSMCs. VSMCs were treated with N-BP or pretreated with downstream products of farnesyl pyrophosphate synthase(FPPS) in mevalonate pathway, such as farnesol (FOH) or geranylgeraniol (GGOH). Alizarin red S staining and determination of calcium content were used to detect calcium deposition.Western Blotting were used to detect expressions of proteins(OPG and RANKL ) and osteogenic marker proteins (Runx2 and OPN). RESULTS: ß-GP induced the osteogenic differentiation and calcification in VSMCs, increased RANKL protein expression and had no significant effect on OPG protein expression. With the treatment of N-BP, the expression of OPG protein was increased and expression of RANKL protein was decreased in VSMCs undergoing osteogenic differentiation and calcification. In addition, N-BP reduced the osteogenic marker proteins (Runx2 and OPN) expression and calcium deposition in VSMCs undergoing osteogenic differentiation and calcification. These effects of N-BP on the osteogenic differentiation and calcification in VSMCs were concentration-dependent, which could be reversed by the downstream products of FPPS, such as FOH or GGOH. CONCLUSION: N-BP increases OPG expression and decreases RANKL expression via inhibition of FPPS to inhibit the osteogenic differentiation and calcification in VSMCs.

Extra-osseous Roles of the RANK-RANKL-OPG Axis with a Focus on Skeletal Muscle.

PURPOSE OF REVIEW: This review aims to consolidate recent observations regarding extra-osseous roles of the RANK-RANKL-OPG axis, primarily within skeletal muscle. RECENT FINDINGS: Preclinical efforts to decipher a common signalling pathway that links the synchronous decline in bone and muscle health in ageing and disease disclosed a potential role of the RANK-RANKL-OPG axis in skeletal muscle. Evidence suggests RANKL inhibition benefits skeletal muscle function, mass, fibre-type switching, calcium homeostasis and reduces fall incidence. However, there still exists ambiguity regarding the exact mechanistic actions and subsequent functional improvements. Other potential RANK-RANKL-OPG extra-osseous roles include regulation of neural-inflammation and glucose metabolism. Growing evidence suggests the RANK-RANKL-OPG axis may play a regulatory role in extra-osseous tissues, especially in skeletal muscle. Targeting RANKL may be a novel therapy in ameliorating loss of muscle mass and function. More research is warranted to determine the causality of the RANK-RANKL-OPG axis in extra-osseous tissues, especially those affected by aging.

Protective effect of carvacrol hydrogel on the alveolar bone in rats with periodontitis.

OBJECTIVES: This study aimed to investigate the protective effect and mechanism of carvacrol hydrogel on the alveolar bone in rats with periodontitis. METHODS: A thermosensitive hydrogel supported by carvacrol was prepared using poloxamer and hydroxypropyl methyl cellulose as matrix. SD rats were randomly divided into blank group, periodontitis group, blank hydrogel group, and low-, medium-, and high-dose hydrogel groups. The periodontitis symptoms and the CT structure of the alveolar bone were observed. The changes in liver, spleen, kidney, and periodontal tissues were observed. The related indexes of bone metabolism in serum were detected. The expression of osteoprotegerin (OPG) and nuclear transcription factor-κB (NF-κB) pathway proteins was determined by Western blot. The levels of inflammatory factors were assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: Carvacrol hydrogel had good slow release, biocompatibility, and cell adhesion. The periodontitis of rats in the carvacrol hydrogel group was significantly alleviated, the expression of OPG protein in gingival tissue was significantly increased (P<0.01), and the levels of receptor activator of NF-κB ligand (RANKL), receptor activator of NF-κB (RANK), NF-κB protein, and inflammatory factors were significantly decreased (P<0.01). CONCLUSIONS: Carvacrol hydrogel can regulate the OPG and NF-κB pathways, reduce alveolar bone absorption, and improve periodontal inflammation.

Inhibition of 12/15-lipoxygenase reduces orthodontically induced root resorption in rats.

OBJECTIVES: To investigate whether the inhibition of 12/15-lipoxygenase (12/15-LOX), one of the core enzymes of the arachidonic acid cascade, suppresses orthodontically induced root resorption (OIRR), and examine the involvement of the hyaline degeneration of periodontal ligament cells and odontoclast differentiation. MATERIALS AND METHODS: The left maxillary first molars of 10-week-old male Wistar rats were moved mesially for 14 days using a closed-coil spring (25 cN) inserted between the first molar and incisor. The rats were intraperitoneally administered with a 12/15-LOX specific inhibitor (ML-351; 0.05 mmol/kg) daily in the experimental group or vehicle (dimethyl sulfoxide) in the control group. Tooth movement was measured using microcomputed tomography on day 14. The appearance of OIRR, hyaline degeneration, osteoclasts, and odontoclasts was evaluated via histological analysis. Immunohistochemical staining for receptor-activated NF-kB ligand (RANKL) and osteoprotegerin was performed. RESULTS: OIRR observed on day 14 in the control group was strongly suppressed by ML-351 treatment. Hyaline degeneration observed on the compression side on day 3 and the appearance of osteoclasts and odontoclasts on days 3 and 14 were significantly suppressed by ML-351. RANKL expression on day 3 was significantly suppressed by ML-351. These key processes in OIRR were substantially suppressed by ML-351 treatment. CONCLUSIONS: Inhibition of 12/15-LOX reduced OIRR by suppressing hyaline degeneration and subsequent odontoclast differentiation.

Effect of estrogen depression on alveolar bone microarchitecture and periodontal ligament cells during orthodontic movement.

This study aimed to evaluate the effects of the estrogen depression during orthodontic tooth movement on alveolar bone microarchitecture and periodontal ligament. Female Wistar rats were divided into two groups, one consisting of non-ovariectomized animals subjected to orthodontic tooth movement, and one comprising ovariectomized animals subjected to orthodontic tooth movement. Micro-CT assessment of bone volume to total volume (BV/TV), total porosity, trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) in the alveolar bone of the orthodontically moved tooth was performed. Histomorphometric analyses were made in the periodontal ligament, and immunoexpression of RANK, RANKL, OPG, and TUNEL were quantified. Orthodontic tooth movement in the group of ovariectomized rats was faster than in non-ovariectomized animals. The alveolar bone area showed lower values of BV/TV and trabecular thickness, and higher bone porosity and trabeculae numbers in the ovariectomized rats. Histological analyses in the ovariectomized group revealed an increase in collagen fibers in the periodontal ligament. The apoptotic cell counts in the periodontal ligament were higher in the group of ovariectomized rats than in the sham-operated rats. Ovariectomy resulted in an increase in tooth movement and alteration of the alveolar bone microstructure in the first 7 day of orthodontic tooth movement, and in the presence of apoptotic cells in the periodontal ligament.

KAT6A/YAP/TEAD4 pathway modulates osteoclastogenesis by regulating the RANKL/OPG ratio on the compression side during orthodontic tooth movement.

BACKGROUND: Orthodontic tooth movement (OTM) is a dynamic equilibrium of bone remodeling, involving the osteogenesis of new bone and the osteoclastogenesis of old bone, which is mediated by mechanical force. Periodontal ligament stem cells (PDLCSs) in the periodontal ligament (PDL) space can transmit mechanical signals and regulate osteoclastogenesis during OTM. KAT6A is a histone acetyltransferase that plays a part in the differentiation of stem cells. However, whether KAT6A is involved in the regulation of osteoclastogenesis by PDLSCs remains unclear. RESULTS: In this study, we used the force-induced OTM model and observed that KAT6A was increased on the compression side of PDL during OTM, and also increased in PDLSCs under compression force in vitro. Repression of KAT6A by WM1119, a KAT6A inhibitor, markedly decreased the distance of OTM. Knockdown of KAT6A in PDLSCs decreased the RANKL/OPG ratio and osteoclastogenesis of THP-1. Mechanistically, KAT6A promoted osteoclastogenesis by binding and acetylating YAP, simultaneously regulating the YAP/TEAD axis and increasing the RANKL/OPG ratio in PDLSCs. TED-347, a YAP-TEAD4 interaction inhibitor, partly attenuated the elevation of the RANKL/OPG ratio induced by mechanical force. CONCLUSION: Our study showed that the PDLSCs modulated osteoclastogenesis and increased the RANKL/OPG ratio under mechanical force through the KAT6A/YAP/TEAD4 pathway. KAT6A might be a novel target to accelerate OTM.

Gingerol nanoparticles attenuate complete Freund adjuvant-induced arthritis in rats via targeting the RANKL/OPG signaling pathway.

Rheumatoid arthritis (RA) is characterized by inflammatory joint pathology leading to the degradation of articular bone and cartilage, primarily triggered by synovial inflammation, resulting in joint discomfort. The metacarpophalangeal and proximal interphalangeal joints are predominantly affected. Treatment typically involves a combination of biological and synthetic disease-modifying antirheumatic drugs (DAMARDs) alongside steroid therapy. The application of nanomedicine has been instrumental in enhancing treatment efficacy by facilitating controlled release of pharmacologically active compounds, thus augmenting bioavailability and enabling targeted drug delivery. Gingerol, a constituent of ginger, possesses multifaceted properties. including anti-inflammatory, anti-oxidant, antidiabetic, and antipyretic effects. In this study, gingerol-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), coated with chitosan, were administered orally to rats over a period of 21 days to address RA induced by complete Freund adjuvant (CFA). The rats were segregated into four experimental groups. Upon completion of the treatment regimen, blood samples were collected for the assessment of cyclooxygenase-2 (COX-2), RA factor, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Subsequent gene expression analysis was conducted to evaluate the levels of interleukin-4 (IL-4), interleukin-17a (IL-17a), IL-6, interferon-gamma (INF-γ), TNF-α, interleukin-1 beta (IL-1ß), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL). Statistical analyses utilizing one-way ANOVA followed by Tukey tests were applied to the data. The gene expression profiling revealed significant disparities in mRNA levels of IL-1ß, IL-6, IL-4, IL-17a, RANKL, INF-γ, and TNF-α between the CFA-induced arthritis group and the control group. Consequently, it was inferred that gingerol-loaded PLGA NPs coated with chitosan exhibited heightened therapeutic efficacy in addressing CFA-induced arthritis in rats.