Both 25-hydroxyvitamin-D3 and 1,25-dihydroxyvitamin-D3 reduces inflammatory response in human periodontal ligament cells

Topical Vitamin D Prevents Bone Loss and Inflammation in a Mouse Model

There is a strong association between vitamin D levels and periodontal disease based on numerous epidemiological studies. We have previously shown that experimental deficiency of serum vitamin D in mice leads to gingival inflammation and alveolar bone loss. Treatment of cultured oral epithelial cells with the active form of vitamin D, 1,25(OH)2 vitamin D3 (1,25(OH)2D3), inhibits the extracellular growth and intracellular invasion of bacteria associated with periodontal disease. Maintenance of periodontal health may be due in part to the anti-inflammatory activities of vitamin D. Furthermore, this hormone can induce the expression of an antimicrobial peptide in cultured oral epithelial cells. We have shown that oral epithelial cells are capable of converting inactive vitamin D to the active form, suggesting that topical treatment of the oral epithelium with inactive vitamin D could prevent the development of periodontitis. We subjected mice to ligature-induced periodontitis (LIP), followed by daily treatment with inactive vitamin D or 1,25(OH)2D3. Treatment with both forms led to a reduction in ligature-induced bone loss and inflammation. Gingival tissues obtained from vitamin D-treated LIP showed production of specialized proresolving mediators (SPM) of inflammation. To examine the mechanism, we demonstrated that apical treatment of 3-dimensional cultures of primary gingival epithelial cells with vitamin D prevented lipopolysaccharide-induced secretion of proinflammatory cytokines and led to a similar production of SPM. Analysis of the oral microbiome of the mice treated with vitamin D showed significant changes in resident bacteria, which reflects a shift toward health-associated species. Together, our results show that topical treatment of oral tissues with inactive vitamin D can lead to the maintenance of periodontal health through the regulation of a healthy microbiome and the stimulation of resolution of inflammation. This strongly supports the development of a safe and effective vitamin D-based topical treatment or preventive agent for periodontal inflammation and disease.

Enhancement of innate immunity in gingival epithelial cells by vitamin D and HDAC inhibitors

Introduction

The human host defense peptide LL-37 is a component of the innate immune defense mechanisms of the oral cavity against colonization by microbes associated with periodontal disease. We have previously shown that the active form of vitamin D, 1,25(OH)2D3, can induce the expression of LL-37 in gingival epithelial cells (GEC), and prevent the invasion and growth of periopathogenic bacteria in these cells. Further, experimental vitamin D deficiency resulted in increased gingival inflammation and alveolar bone loss. Epidemiological studies have shown associations between vitamin D deficiency and periodontal disease in humans, suggesting application of vitamin D could be a useful therapeutic approach. Further, since we have shown the local activation of vitamin D by enzymes expressed in the GEC, we hypothesized that we could observe this enhancement with the stable, and inexpensive inactive form of vitamin D, which could be further increased with epigenetic regulators.

Methods

We treated 3-dimensional primary cultures of GEC topically with the inactive form of vitamin D, in the presence and absence of selected histone deacetylase (HDAC) inhibitors. LL-37 mRNA levels were quantified by quantitative RT-PCR, and inhibition of invasion of bacteria was measured by fluorescence microscopy.

Results

Vitamin D treatment led to an induction of LL-37 mRNA levels, as well as an inhibition of pro-inflammatory cytokine secretion. This effect was further enhanced by HDAC inhibitors, most strongly when the HDAC inhibitor, phenyl butyrate (PBA) was combined with Vitamin D3. This was observed both in solution and in a prototype gel formulation using sodium butyrate. Finally, this combination treatment led to an increase in the antimicrobial activity against infection by Porphyromonas gingivalis and Filifactor alocis, bacteria associated with periodontal lesions, as well as herpes simplex virus, which has also been shown to be associated with periodontal lesions.

Conclusions

Our results demonstrate that a combination of inactive vitamin D and sodium butyrate could be developed as a safe treatment for periodontal disease.

Estimation of Serum 1,25-Dihydroxycholecalciferol and Tumor Necrosis Factor-α Levels in Chronic Periodontitis

BACKGROUND

Major trials in the field of periodontics include a thorough understanding of its pathophysiology and the interplay between host response and periodontal factors. Certain factors such as vitamin D play a crucial role in immune regulation and their depletion is known to contribute to the onset of periodontitis. Research efforts continue to unravel the impact of elevated pro-inflammatory cytokines like TNF-α on osteoclastogenesis in periodontitis.

MATERIALS AND METHODS

The study comprised a total of 64 participants, with 33 men and 31 women, including 32 individuals with chronic periodontitis and 32 people without the condition. ELISA was employed to determine the concentrations of TNF-α and 1,25-dihydroxycholecalciferol (1,25(OH)2D) in the participants. Clinical attachment levels, probing pocket depth, gingival bleeding index, and plaque index were meticulously measured. Subsequent to data collection, appropriate statistical tests were conducted.

RESULTS

The mean serum levels of 1,25(OH)2D in test and control groups are 173.59 ± 52.60 and 401.47 ± 99.81, respectively. The mean serum levels of TNF-α in the test and control groups are 1078.09 ± 231.51 and 204.75 ± 68.31, respectively. The TNF-α levels exhibited a statistically significant difference between test and control groups (p = 0.0001) at a 5% level of significance.

CONCLUSION

Decreased levels of 1,25(OH)2D led to increased values of periodontal parameters. There was also a significant increase in serum levels of pro-inflammatory cytokines such as TNF-α.

The role of vitamin D in periodontal health and disease

Vitamin D plays an essential role in calcium and bone metabolism, immune regulation and possesses profound anti-inflammatory effects. Evidence suggests that low serum vitamin D is associated with increased severity of periodontitis, a chronic inflammatory condition characterised by destruction of the supporting tissues surrounding the tooth, which has several shared risk factors with other chronic non-communicable diseases. The biological functions of vitamin D are mediated by its strong anti-microbial, anti-inflammatory, and host modulatory properties. Experimental periodontitis models involving targeted deletion of 1α-hydroxylase, the enzyme responsible for the conversion of inactive substrate to active 1,25(OH)₂ D₃ (calcitriol), showed augmented alveolar bone loss and gingival inflammation. Vitamin D receptor (VDR) gene polymorphisms have also been associated with increased severity of periodontitis. Thus, the involvement of vitamin D in the pathogenesis of periodontitis is biological plausible. Clinical studies have consistently demonstrated an inverse relationship between serum 25OHD₃ and periodontal disease inflammation. However, due to the paucity of well-designed longitudinal studies, there is less support for the impact of vitamin D status on periodontal disease progression and tooth loss. The evidence emphasises the importance of maintaining vitamin D sufficiency in supporting periodontal health. This review aims to first examine the biological mechanisms by which vitamin D might influence the pathogenesis of periodontal disease and second, discuss the clinical evidence which implicate the role of vitamin D in periodontal disease.

Association between circulating 25-hydroxyvitamin D metabolites and periodontitis: Results from the NHANES 2009-2012 and Mendelian randomization study

AIM

This study sought to investigate associations of 25-hydroxyvitamin D (25(OH)D) metabolites with periodontitis and to assess causality using Mendelian randomization (MR).

MATERIALS AND METHODS

This study included 7246 participants of the National Health and Nutrition Examination Survey, 2009-2012. The association of periodontitis with 25(OH)D metabolites was assessed using multivariable logistic regression analysis. Two-sample MR for 25(OH)D, 25(OH)D₃ , and C3-epi-25(OH)D₃ with periodontitis (n = 17,353 cases/28,210 controls) was conducted. The principal analysis employed the inverse-variance-weighted (IVW) approach. We controlled for horizontal pleiotropy using five additional methods.

RESULTS

Based on the observational study, each 1-point increase in standard deviation of 25(OH)D lowered the risk of periodontitis by 15% (OR = 0.85, 95% confidence interval [CI]: 0.78-0.93, p = .006) after multivariable adjustment. A similar relationship was observed between 25(OH)D₃ and periodontitis (OR = 0.88, 95% CI: 0.80-0.97, p = .031). Furthermore, a potential non-linear association was found between periodontitis and both 25(OH)D and 25(OH)D₃ . However, C3-epi-25(OH)D₃ was not found to be associated with periodontitis risk. IVW-MR showed that periodontitis risk was not significantly associated with genetically increased levels of 25(OH)D (OR = 1.02, 95% CI: 0.90-1.16, p = .732), 25(OH)D₃ (OR = 1.04, 95% CI: 0.93-1.17, p = .472), or C3-epi-25(OH)D₃ (OR = 1.11, 95% CI: 0.87-1.41, p = .400). The pleiotropy-robust MR approaches yielded similar results after we had eliminated the variants with horizontal pleiotropy risk.

CONCLUSIONS

Cross-sectional observational analysis identified significant relationships between periodontitis with 25(OH)D metabolites, while findings based on MR study did not support a causal role.

25-hydroxyvitamin D3 generates immunomodulatory plasticity in human periodontal ligament-derived mesenchymal stromal cells that is inflammatory context-dependent

Introduction

Human periodontal ligament-derived mesenchymal stromal cells (hPDL-MSCs) exhibit a tight bi-directional interaction with CD4+ T lymphocytes. The hPDL-MSCs' immunomodulatory abilities are drastically enhanced by pro-inflammatory cytokines via boosting the expression of various immunomediators. 25-hydroxyvitamin D3 (25(OH)D3), the major metabolite of vitamin D3 in the blood, affects both hPDL-MSCs and CD4+ T lymphocytes, but its influence on their interaction is unknown.

Methods

Therefore, primary hPDL-MSCs were stimulated in vitro with tumor necrosis factor (TNF)-α a or interleukin (IL)-1β in the absence and presence of 25(OH)D3 followed by an indirect co-culture with phytohemagglutinin-activated CD4+ T lymphocytes. The CD4+ T lymphocyte proliferation, viability, and cytokine secretion were analyzed. Additionally, the expression of various immunomediators in hPDL-MSCs was investigated, and their implication was verified by using pharmacological inhibitors.

Results

25(OH)D3 significantly counteracted the suppressive effects of IL-1β-treated hPDL-MSCs on CD4+ T lymphocyte proliferation, whereas no effects were observed in the presence of TNF-α. Additionally, 25(OH)D3 significantly increased the percentage of viable CD4+ T lymphocytes via TNF-α- or IL-1β-treated hPDL-MSCs. It also caused a significant decrease in interferon-γ, IL-17A, and transforming growth factor-β productions, which were triggered by TNF-α-treated hPDL-MSCs. 25(OH)D3 significantly decreased the production of various immunomediators in hPDL-MSCs. Inhibition of two of them, prostaglandin E2 and indoleamine-2,3-dioxygenase-1, partially abolished some of the hPDL-MSCs-mediated effects of 25(OH)D3 on CD4+ T lymphocytes.

Conclusion

These data indicate that 25(OH)D3 influences the immunomodulatory activities of hPDL-MSCs. This modulatory potential seems to have high plasticity depending on the local cytokine conditions and may be involved in regulating periodontal tissue inflammatory processes.

Influence of Single-Nucleotide Polymorphisms on Vitamin D Receptor Expression in Periodontal Ligament Fibroblasts as a Response to Orthodontic Compression

This study aimed to evaluate if single-nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene are associated with gene expression in human periodontal ligament (hPDL) fibroblasts under simulated orthodontic compressive force. hPDL samples from 57 patients were used. A physiological compressive strain was performed to simulate orthodontic tooth movement in pressure areas under cell culture conditions. The RNA from hPDL fibroblasts was isolated to determine the relative gene expression (mRNA) of the VDR. The DNA was also isolated for the genotyping analysis of five SNPs in the VDR gene: BglI (rs739837, G/T), BsmI (rs1544410, T/C), ApaI (rs7975232, A/C), FokI (rs2228570, A/G), and TaqI (rs731236, A/G). Real-time polymerase chain reaction was used for both analyses. Kruskal−Wallis tests were used to compare VDR expression among genotypes of each SNP. A linear regression analysis was performed to evaluate SNP−SNP interaction. An established alpha of 5% was used. The relative mRNA VDR expression according to the genotypes in the SNPs BglI, BsmI, ApaI, FokI, and TaqI was not statistically significantly different (p > 0.05). The SNP−SNP interaction evaluated by regression analysis did not demonstrate any statistically significant association. No association was observed (p > 0.05). In conclusion, the SNPs BglI (rs739837), BsmI (rs1544410), ApaI (rs7975232), FokI (rs2228570), and TaqI (rs731236) did not show an impact on VDR gene expression in hPDL fibroblasts under simulated orthodontic compressive force.

Type 2 Diabetes Contributes to Altered Adaptive Immune Responses and Vascular Inflammation in Patients With SARS-CoV-2 Infection

SARS-CoV-2, which initially emerged in November of 2019, wreaked havoc across the globe by leading to clinical acute respiratory distress syndrome and continues to evade current therapies today due to mutating strains. Diabetes mellitus is considered an important risk factor for progression to severe COVID disease and death, therefore additional research is warranted in this group. Individuals with diabetes at baseline have an underlying inflammatory state with elevated levels of pro-inflammatory cytokines and lower levels of anti-inflammatory cytokines, both of which cause these individuals to have higher susceptibility to SARS- CoV2 infection. The detrimental effects of SARS-CoV-2 has been attributed to its ability to induce a vast cell mediated immune response leading to a surge in the levels of pro-inflammatory cytokines. This paper will be exploring the underlying mechanisms and pathophysiology in individuals with diabetes and insulin resistance making them more prone to have worse outcomes after SARS- CoV2 infection, and to propose an adjunctive therapy to help combat the cytokine surge seen in COVID-19. It will also look at the immunomodulatory effects of glutathione, an antioxidant shown to reduce immune dysregulation in other diseases; Vitamin D, which has been shown to prevent COVID-19 patients from requiring more intensive care time possibly due to its ability to decrease the expression of certain pro-inflammatory cytokines; and steroids, which have been used as immune modulators despite their ability to exacerbate hyperglycemia.

The role of 25-hydroxyvitamin-D3 and vitamin D receptor gene in human periodontal ligament fibroblasts as response to orthodontic compressive strain: an in vitro study

Background

This study aimed to investigate, if different physiological concentrations of vitamin D (25(OH)D₃) and single nucleotide polymorphisms in vitamin D receptor (VDR) gene have an impact on gene expression in human periodontal ligament (hPDL) fibroblasts induced by simulated orthodontic compressive strain.

Methods

A pool of hPDL fibroblasts was treated in absence or presence of 25(OH)D₃ in 3 different concentrations (10, 40 and 60 ng/ml). In order to evaluate the role of single nucleotide polymorphisms in the VDR gene, hPDL fibroblasts from 9 patients were used and treated in absence or presence of 40 ng/ml 25(OH)D₃. Each experiment was performed with and without simulated orthodontic compressive strain. Real-time PCR was used for gene expression and allelic discrimination analysis. Relative expression of dehydrocholesterol reductase (DHCR7), Sec23 homolog A, amidohydrolase domain containing 1 (AMDHD1), vitamin D 25-hydroxylase (CYP2R1), Hydroxyvitamin D-1-α hydroxylase, receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), cyclooxygenase-2 (COX-2) and interleukin-6 (IL6) was assessed. Three single nucleotide polymorphisms in VDR were genotyped. Parametric or non-parametric tests were used with an alpha of 5%.

Results

RANKL, RANKL:OPG ratio, COX-2, IL-6, DHCR7, CYP2R1 and AMDHD1 were differentially expressed during simulated orthodontic compressive strain (p < 0.05). The RANKL:OPG ratio was downregulated by all concentrations (10 ng/ml, 40 ng/ml and 60 ng/ml) of 25(OH)D₃ (mean = 0.96 ± 0.68, mean = 1.61 ± 0.66 and mean = 1.86 ± 0.78, respectively) in comparison to the control (mean 2.58 ± 1.16) (p < 0.05). CYP2R1 gene expression was statistically modulated by the different 25(OH)D₃ concentrations applied (p = 0.008). Samples from individuals carrying the GG genotype in rs739837 presented lower VDR mRNA expression and samples from individuals carrying the CC genotype in rs7975232 presented higher VDR mRNA expression (p < 0.05).

Conclusions

Simulated orthodontic compressive strain and physiological concentrations of 25(OH)D₃ seem to regulate the expression of orthodontic tooth movement and vitamin-D-related genes in periodontal ligament fibroblasts in the context of orthodontic compressive strain. Our study also suggests that single nucleotide polymorphisms in the VDR gene regulate VDR expression in periodontal ligament fibroblasts in the context of orthodontic compressive strain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01740-8.

Calcifediol Treatment and Hospital Mortality Due to COVID-19: A Cohort Study

Context. Calcifediol has been proposed as a potential treatment for COVID-19 patients. Objective: To compare the administration or not of oral calcifediol on mortality risk of patients hospitalized because of COVID-19. Design: Retrospective, multicenter, open, non-randomized cohort study. Settings: Hospitalized care. Patients: Patients with laboratory-confirmed COVID-19 between 5 February and 5 May 2020 in five hospitals in the South of Spain. Intervention: Patients received calcifediol (25-hydroxyvitamin D₃) treatment (0.266 mg/capsule, 2 capsules on entry and then one capsule on day 3, 7, 14, 21, and 28) or not. Main Outcome Measure: In-hospital mortality during the first 30 days after admission. Results: A total of 537 patients were hospitalized with COVID-19 (317 males (59%), median age, 70 years), and 79 (14.7%) received calcifediol treatment. Overall, in-hospital mortality during the first 30 days was 17.5%. The OR of death for patients receiving calcifediol (mortality rate of 5%) was 0.22 (95% CI, 0.08 to 0.61) compared to patients not receiving such treatment (mortality rate of 20%; p < 0.01). Patients who received calcifediol after admission were more likely than those not receiving treatment to have comorbidity and a lower rate of CURB-65 score for pneumonia severity ≥ 3 (one point for each of confusion, urea > 7 mmol/L, respiratory rate ≥ 30/min, systolic blood pressure < 90 mm Hg or diastolic blood pressure ≤ 60 mm Hg, and age ≥ 65 years), acute respiratory distress syndrome (moderate or severe), c-reactive protein, chronic kidney disease, and blood urea nitrogen. In a multivariable logistic regression model, adjusting for confounders, there were significant differences in mortality for patients receiving calcifediol compared with patients not receiving it (OR = 0.16 (95% CI 0.03 to 0.80). Conclusion: Among patients hospitalized with COVID-19, treatment with calcifediol, compared with those not receiving calcifediol, was significantly associated with lower in-hospital mortality during the first 30 days. The observational design and sample size may limit the interpretation of these findings.

Effect of vitamin D3 on the osteogenic differentiation of human periodontal ligament stromal cells under inflammatory conditions

Objectives

Vitamin D₃ is known to activate osteogenic differentiation of human periodontal ligament stromal cells (hPDLSCs). Recently, inflammatory stimuli were shown to inhibit the transcriptional activity of hPDLSCs, but their effect on vitamin D₃‐induced osteogenic differentiation is not known. The present study aimed to investigate whether the effects of 1,25‐dihydroxvitamin D₃ (1,25(OH)₂D₃) and 25‐hydroxvitamin D₃ (25(OH)D₃) on the osteogenic differentiation of hPDLSCs are also altered under inflammatory conditions. Furthermore, the expression of osteogenesis‐related factors by hPDLSCs under osteogenic conditions was assessed in the presence of inflammatory stimuli.

Materials and Methods

Primary hPDLSCs of six donors were cultured in osteogenic induction medium containing either 1,25(OH)₂D₃ (0‐10 nM) or 25(OH)D₃ (0‐100 nM) in the presence and absence of Porphyromonas gingivalis lipopolysaccharide (LPS) or Pam3CSK4 for 7, 14 and 21 days. Osteogenic differentiation of hPDLSCs was evaluated by analysis of mineralization as assessed by Alizarin Red S staining and gene expression levels of osteogenesis‐related factors osteocalcin, osteopontin and runt‐related transcription factor 2 (RUNX2) were analysed with qPCR.

Results

Treatment with 1,25(OH)₂D₃ significantly enhanced the osteogenic differentiation of hPDLSCs and their expression of osteocalcin and osteopontin. The 1,25(OH)₂D₃‐triggered expression of osteogenesis‐related factors was significantly lower in the presence of Pam3CSK4, but not P. gingivalis LPS. None of the inflammatory stimuli had significant effects on the 1,25(OH)₂D₃‐induced osteogenic differentiation. 25(OH)D₃ neither affected gene expression levels nor osteogenic differentiation of hPDLSCs cultured in osteogenic induction medium.

Conclusion

The results of this study indicate that inflammatory stimuli also diminish the 1,25(OH)₂D₃‐induced expression of osteogenesis‐related factors in hPDLSCs under osteogenic conditions, while having no effect on the osteogenic differentiation.

Effect of Multi-Phosphonate Coating of Titanium Surfaces on Osteogenic Potential

The aim of this study was to evaluate the impact of a novel multi-phosphonate (MP) coating strategy of dental implant surfaces on the expression of osteogenesis-related factors in vitro. MG-63 human osteoblast-like cells, bone marrow mesenchymal stem cells (BM-MSCs), and human periodontal ligament stem cells (hPDLSCs) were cultured separately on titanium disks with and without MP coating. Cell attachment was visualized by focal adhesion and actin cytoskeleton staining. The proliferation and gene expression of the markers related to osteogenesis and bone turnover were measured after 48 and 120 h of cell culture. Actin cytoskeleton assembly and focal adhesion were similar between test surfaces within each cell type but differed from those on tissue culture plastic (TCP). The proliferation of MG-63 cells and PDLSCs was comparable on all surfaces, while BM-MSCs showed an increase on tissue culture plastic (TCP) versus titanium. The gene expression of osteoprotegerin and receptor activator of nuclear factor-kappa B ligand was higher in MG-63 cells grown on MP-coated surfaces. At the same time, osteocalcin was decreased compared to the other surfaces. Collagen type I gene expression after 120 h was significantly lower in hPDLSCs cultivated on MP-coated surfaces. Within the limitations of this study, MP coating on titanium surfaces might have a slight beneficial effect on bone turnover in vitro.

Mechanisms involved in regulation of periodontal ligament cell production of pro-inflammatory cytokines: Implications in periodontitis

It is well recognized that human periodontal ligament cells (PDL cells) may represent local immune cells of the periodontal tissues. However, it is unclear whether they represent “true” immune cells, since they can produce pro‐inflammatory cytokines not only after stimulation with bacterial lipopolysaccharides but also in response to other stimuli such as mechanical stress. Stimulation with bacterial lipopolysaccharides strongly enhances PDL cell production of pro‐inflammatory cytokines through activation of toll‐like receptors and NF‐κB signaling. Less information is available regarding putative modulators of cytokine production and their mechanisms of action in PDL cells. The anti‐inflammatory glucocorticoid dexamethasone reduces lipopolysaccharide‐induced PDL cell production of cytokines. Recent observations show that vitamin D and the antimicrobial peptide LL‐37 antagonize lipopolysaccharide‐stimulated PDL cell production of pro‐inflammatory cytokines. Secretory leukocyte protease inhibitor is endogenously expressed by PDL cells, and this protein negatively regulates PDL cell‐evoked cytokine production. More information and knowledge about the regulation of PDL cell production of cytokines may clarify the role of PDL cells in oral innate immunity and their importance in periodontitis.

"Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: A pilot randomized clinical study"

OBJECTIVE

The vitamin D endocrine system may have a variety of actions on cells and tissues involved in COVID-19 progression especially by decreasing the Acute Respiratory Distress Syndrome. Calcifediol can rapidly increase serum 25OHD concentration. We therefore evaluated the effect of calcifediol treatment, on Intensive Care Unit Admission and Mortality rate among Spanish patients hospitalized for COVID-19.

DESIGN

Parallel pilot randomized open label, double-masked clinical trial.

SETTING

University hospital setting (Reina Sofia University Hospital, Córdoba Spain.) PARTICIPANTS: 76 consecutive patients hospitalized with COVID-19 infection, clinical picture of acute respiratory infection, confirmed by a radiographic pattern of viral pneumonia and by a positive SARS-CoV-2 PCR with CURB65 severity scale (recommending hospital admission in case of total score > 1).

PROCEDURES

All hospitalized patients received as best available therapy the same standard care, (per hospital protocol), of a combination of hydroxychloroquine (400 mg every 12 h on the first day, and 200 mg every 12 h for the following 5 days), azithromycin (500 mg orally for 5 days. Eligible patients were allocated at a 2 calcifediol:1 no calcifediol ratio through electronic randomization on the day of admission to take oral calcifediol (0.532 mg), or not. Patients in the calcifediol treatment group continued with oral calcifediol (0.266 mg) on day 3 and 7, and then weekly until discharge or ICU admission. Outcomes of effectiveness included rate of ICU admission and deaths.

RESULTS

Of 50 patients treated with calcifediol, one required admission to the ICU (2%), while of 26 untreated patients, 13 required admission (50 %) p value X² Fischer test p < 0.001. Univariate Risk Estimate Odds Ratio for ICU in patients with Calcifediol treatment versus without Calcifediol treatment: 0.02 (95 %CI 0.002-0.17). Multivariate Risk Estimate Odds Ratio for ICU in patients with Calcifediol treatment vs Without Calcifediol treatment ICU (adjusting by Hypertension and T2DM): 0.03 (95 %CI: 0.003-0.25). Of the patients treated with calcifediol, none died, and all were discharged, without complications. The 13 patients not treated with calcifediol, who were not admitted to the ICU, were discharged. Of the 13 patients admitted to the ICU, two died and the remaining 11 were discharged.

CONCLUSION

Our pilot study demonstrated that administration of a high dose of Calcifediol or 25-hydroxyvitamin D, a main metabolite of vitamin D endocrine system, significantly reduced the need for ICU treatment of patients requiring hospitalization due to proven COVID-19. Calcifediol seems to be able to reduce severity of the disease, but larger trials with groups properly matched will be required to show a definitive answer.

Vitamin D receptor stimulation to reduce acute respiratory distress syndrome (ARDS) in patients with coronavirus SARS-CoV-2 infections: Revised Ms SBMB 2020_166

Coronavirus infection is a serious health problem awaiting an effective vaccine and/or antiviral treatment. The major complication of coronavirus disease 2019 (COVID-19), the Acute Respiratory Distress syndrome (ARDS), is due to a variety of mechanisms including cytokine storm, dysregulation of the renin-angiotensin system, neutrophil activation and increased (micro)coagulation. Based on many preclinical studies and observational data in humans, ARDS may be aggravated by vitamin D deficiency and tapered down by activation of the vitamin D receptor. Several randomized clinical trials using either oral vitamin D or oral Calcifediol (25OHD) are ongoing. Based on a pilot study, oral calcifediol may be the most promising approach. These studies are expected to provide guidelines within a few months.

Vitamin D3 and Dental Mesenchymal Stromal Cells

Vitamin D3 is a hormone involved in the regulation of bone metabolism, mineral homeostasis, and immune response. Almost all dental tissues contain resident mesenchymal stromal cells (MSCs), which are largely similar to bone marrow-derived MSCs. In this narrative review, we summarized the current findings concerning the physiological effects of vitamin D3 on dental MSCs. The existing literature suggests that dental MSCs possess the ability to convert vitamin D3 into 25(OH)D3 and subsequently to the biologically active 1,25(OH)2D3. The vitamin D3 metabolites 25(OH)D3 and 1,25(OH)2D3 stimulate osteogenic differentiation and diminish the inflammatory response of dental MSCs. In addition, 1,25(OH)2D3 influences the immunomodulatory properties of MSCs in different dental tissues. Thus, dental MSCs are both producers and targets of 1,25(OH)2D3 and might regulate the local vitamin D3-dependent processes in an autocrine/paracrine manner. The local vitamin D3 metabolism is assumed to play an essential role in the local physiological processes, but the mechanisms of its regulation in dental MSCs are mostly unknown. The alteration of the local vitamin D3 metabolism may unravel novel therapeutic modalities for the treatment of periodontitis as well as new strategies for dental tissue regeneration.

Transcriptional activity of vitamin D receptor in human periodontal ligament cells is diminished under inflammatory conditions

Background

Although vitamin D₃ deficiency is considered as a risk factor for periodontitis, supplementation during periodontal treatment has not been shown to be beneficial to date. Human periodontal ligament cells (hPDLCs) are regulated by vitamin D₃ and play a fundamental role in periodontal tissue homeostasis and inflammatory response in periodontitis. The aim of this study is to investigate possible alterations of the vitamin D₃ activity in hPDLCs under inflammatory conditions.

Methods

Cells isolated from six different donors were treated with either 1,25(OH)₂D₃ (0 to 10 nM) or 25(OH)D₃ (0 to 100 nM) in the presence and absence of ultrapure or standard Porphyromonas gingivalis lipopolysaccharide (PgLPS), Pam3CSK4, or interferon‐γ for 48 hours. Additionally, nuclear factor (NF)‐κB inhibition was performed with BAY 11‐7082. The bioactivity of vitamin D in hPDLCs was assessed based on the gene expression levels of vitamin D receptor (VDR)‐regulated genes osteocalcin and osteopontin. Additionally, VDR and CYP27B1 expression levels were measured.

Results

The vitamin D₃‐induced increase of osteocalcin and osteopontin expression was significantly decreased in the presence of standard PgLPS and Pam3CSK4, which was not observed by ultrapure PgLPS. Interferon‐y had diverse effects on the response of hPDLCs to vitamin D₃ metabolites. NF‐kB inhibition abolished the effects of standard PgLPS and Pam3CSK4. Standard PgLPS and Pam3CSK4 increased VDR expression in the presence of vitamin D₃. CYP27B1 expression was not affected by vitamin D₃ and inflammatory conditions.

Conclusions

This study indicates that the transcriptional activity of VDR is diminished under inflammatory conditions, which might mitigate the effectiveness of vitamin D₃ supplementation during periodontal treatment.

Pleiotropic effects of vitamin D3 on CD4+ T lymphocytes mediated by human periodontal ligament cells and inflammatory environment

Aims

Both, vitamin D₃ and human periodontal ligament cells (hPDLCs) possess immunosuppressive properties, but their combined effect on immune cells has never been investigated. Here, we analysed the impact of vitamin D₃ on the immunosuppressive properties of hPDLCs towards CD4⁺ T lymphocytes.

Material and Methods

Allogenic CD4⁺ T lymphocytes were activated by phytohemagglutinin either in monoculture or co‐culture with hPDLCs, in the presence or absence of IFN‐γ and 1,25(OH)₂D₃. After 5 days, CD4⁺ T‐lymphocyte proliferation, CD4⁺ CD25⁺ FoxP3⁺ regulatory T lymphocytes (T_regs) proportion and IL‐10, TGF‐β1 and IL‐17A production were analysed.

Results

In monoculture, 1,25(OH)₂D₃ suppressed CD4⁺ T‐lymphocyte proliferation, increased the percentage of CD4⁺ FoxP3⁺ CD25⁺ FoxP3⁺ T_regs and enhanced IL‐10 and TGF‐β1 production. In the presence of IFN‐γ treated hPDLCs, 1,25(OH)₂D₃ significantly increased CD4⁺ T‐lymphocyte proliferation and decreased the percentage of CD4⁺ CD25⁺ FoxP3⁺ T_regs. IL‐10 and IL‐17A expression was significantly diminished by 1,25(OH)₂D₃, whereas TGF‐β1 was slightly increased. The effects of 1,25(OH)₂D₃ in co‐culture were reversed by inhibition of indoleamine‐2,3‐dioxygenase‐1, prostaglandin‐endoperoxide synthase and programmed cell death 1 ligand 1. 1,25(OH)₂D₃ also suppressed the expression of these proteins in hPDLCs.

Conclusion

Effects of vitamin D₃ on CD4⁺ T lymphocyte are modified by hPDLCs depending on the microenvironment.

1,25(OH)2D3 Differently Affects Immunomodulatory Activities of Mesenchymal Stem Cells Depending on the Presence of TNF-α, IL-1β and IFN-γ

Periodontal ligament-derived mesenchymal stem cells (hPDLSCs) possess immunomodulatory abilities which are strongly enhanced by various inflammatory cytokines. Vitamin D₃ has anti-inflammatory effects on hPDLSCs and immune cells. However, no study to date has directly compared the influence of 1,25(OH)₂D₃ on the immunomodulatory activities of hPDLSCs in the presence of different cytokines. In the present study, the effects of hPDLSCs treated with tumor necrosis factor (TNF)-α, interleukin (IL)-1β, or interferon (IFN)-γ in the presence of 1,25(OH)₂D₃ on the proliferation of allogenic CD4⁺ T lymphocyte or on the functional status of primary CD68⁺ macrophages were analyzed in coculture models. Additionally, the effects of 1,25(OH)₂D₃ on TNF-α-, IL-1β-, and IFN-γ-induced gene expression of some immunomodulatory factors in hPDLSCs were compared. Under coculture conditions, 1,25(OH)₂D₃ increased or decreased CD4⁺ T lymphocyte proliferation via hPDLSCs, depending on the cytokine. hPDLSCs primed with 1,25(OH)₂D₃ and different cytokines affected pro- and anti-inflammatory cytokine expression in macrophages variably, depending on the priming cytokine. With one exception, 1,25(OH)₂D₃ significantly reduced TNF-α-, IL-1β-, and IFN-γ-induced expression of all the investigated immunomediators in hPDLSCs, albeit to different extents. These results suggest that 1,25(OH)₂D₃ influences the immunomodulatory activities of hPDLSCs depending qualitatively and quantitatively on the presence of certain inflammatory cytokines.

Calcitriol suppresses lipopolysaccharide-induced alveolar bone damage in rats by regulating T helper cell subset polarization

BACKGROUND

Although the immunomodulatory properties of calcitriol in bone metabolism have been documented for decades, its therapeutic role in the management of periodontitis remains largely unexplored. In this study, we hypothesized that calcitriol suppresses lipopolysaccharide (LPS)-induced alveolar bone loss by regulating T helper (Th) cell subset polarization.

METHODS

To test this hypothesis, we determined the effect of calcitriol intervention on the development of LPS-induced periodontitis in rats in terms of bone loss (micro-CT analysis), local inflammatory infiltration levels, the number of osteoclasts (hematoxylin and eosin staining) and the level of osteoclastogenesis (tartrate-resistant acid phosphatase method). Furthermore, immunohistochemistry was used to assess the expression levels of the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) as well as the cytokine levels of interferon-γ (IFN-γ), interleukin-4 (IL-4), IL-17, and IL-10 throughout the LPS-injected region. Finally, the polarization potential of Th cells in peripheral blood was analyzed using flow cytometry.

RESULTS

Calcitriol intervention decreased alveolar bone loss in response to LPS injection and inflammatory cell infiltration. Analysis of osteoclast number and RANKL and OPG expression showed that bone resorption activity was largely suppressed in response to calcitriol administration, along with decreased IL-17 levels but increased IL-4 and IL-10 levels in periodontal tissues (the LPS-injected region). Similarly, the percentages of Th2 and Treg cells in peripheral blood increased, but the percentages of Th1 and Th17 cells decreased in rats receiving calcitriol.

CONCLUSION

Our findings suggest that calcitriol can be used to inhibit bone loss in experimental periodontitis, likely via the regulation of local and systemic Th cell polarization.

Investigating unset endodontic sealers' eugenol and hydrocortisone roles in modulating the initial steps of inflammation

INTRODUCTION

Endodontic treatment success is achieved not only when the cement provides a hermetic seal but also when the injured periapical tissue is regenerated. However, an exaggerated inflammatory reaction hinders tissue regeneration and it has been shown that dental materials affect the inflammatory response through modulation of cytokine secretion. This work was set to investigate the effects of the presence of hydrocortisone in zinc oxide eugenol sealers (Endomethasone N) on modulating the initial steps of inflammation in vitro.

MATERIAL AND METHODS

Hydrocortisone and eugenol leaching from Endomethasone N and Pulp Canal Sealer (PCS) were quantified by ELISA and spectrofluorometry, respectively. The effects of Endomethasone N and Pulp Canal Sealer were studied on lipopolysaccharides (LPS)-stimulated human periodontal ligament (hPDL) cells. Cytokine (IL-6, TNF-α) secretion from cells was quantified by ELISA. Inflammatory cell (THP-1) adhesion to activated endothelial cells, their migration and activation were studied in vitro.

RESULTS

Endomethasone N decreased secretion of IL-6 and TNF-α from hPDL cells. THP-1 adhesion to activated endothelial cells (HUVECs) and migration significantly decreased with Endomethasone N while no effect was observed with PCS. Activation of THP-1 decreased with both materials' extracts but was significantly lower with Endomethasone N than with PCS.

CONCLUSION

These results performed in vitro show that Endomethasone N anti-inflammatory effects are due to the presence of hydrocortisone.

CLINICAL RELEVANCE

Endomethasone N has potential local anti-inflammatory effects which appear to be due to its hydrocortisone rather than eugenol content. Decreasing the inflammatory response is a pre-requisite to initiate the periapical healing.

Relationship between Clinical Indicators of Periodontal Disease and Serum Level of Vitamin D

Background: Vitamin D is obtained through food and nutritional supplements, or is synthesized in the skin by sunshine. It is then transferred to the liver and kidney through the bloodstream and hydroxylated by a specific enzyme (cytochrome P450 family 27 subfamilies A member 1, cytochrome P450 family 27 subfamily B member 1) to form 25-hydroxyvitamin D and 1,25-dihydroxy vitamin D. The vitamin D synthesis facilitates calcium and phosphorus absorption from the intestines. The parathyroid hormone helps to synthesize 1,25-dihydroxy vitamin D to aid calcium absorption. Objectives: Many researchers have investigated the relationship between serum vitamin D levels and periodontal disease. And periodontal disease indicators such as bleeding on probing, pocket depth, clinical attachment level, gingival index, and cementoenamel junction-alveolar cresthave been used to identify the effects of vitamin D on periodontal disease. The effects of vitamin D on bacteria or cytokines have also been investigated. In this review article, vitamin D levels according to the status of periodontal disease were summarized. Data sources: PubMed was searched electronically, and randomized clinical trials, cross-sectional studies, and case-control studies were included in the review. Study appraisal and synthesis methods: Articles that the classification of periodontitis was accurately described, indicators for identifying periodontitis was clearly marked, and the form of vitamin D measured in the study was accurately described were selected. Only highly relevant journals were selected and summarized. Results: Most of the research has found positive associations between the serum 25-hydroxyvitamin D level and periodontal health, and the clinical parameters of periodontal disease were reduced by vitamin D. Limitations: Detailed categorization of the characteristics associated with the 25-hydroxyvitamin D level should be needed in future studies. Conclusions: This review article can be used as a guide by clinicians and as a reference book for patients’ education.

Activation of vitamin D in the gingival epithelium and its role in gingival inflammation and alveolar bone loss

BACKGROUND AND OBJECTIVE

Both chronic and aggressive periodontal disease are associated with vitamin D deficiency. The active form of vitamin D, 1,25(OH)₂ D₃ , induces the expression of the antimicrobial peptide LL-37 and innate immune mediators in cultured human gingival epithelial cells (GECs). The aim of this study was to further delineate the mechanism by which vitamin D enhances the innate defense against the development of periodontal disease (PD).

MATERIALS AND METHODS

Wild-type C57Bl/6 mice were made deficient in vitamin D by dietary restriction. Cultured primary and immortalized GEC were stimulated with 1,25(OH)₂ D₃ , followed by infection with Porphyromonas gingivalis, and viable intracellular bacteria were quantified. Conversion of vitamin D₃ to 25(OH)D₃ and 1,25(OH)₂ D₃ was quantified by ELISA. Effect of vitamin D on basal IL-1α expression in mice was determined by topical administration to the gingiva of wild-type mice, followed by qRT-PCR.

RESULTS

Dietary restriction of vitamin D led to alveolar bone loss and increased inflammation in the gingiva in the mouse model. In primary human GEC and established human cell lines, treatment of GEC with 1,25(OH)₂ D₃ inhibited the intracellular growth of P. gingivalis. Cultured GEC expressed two 25-hydroxylases (CYP27A1 and CYP2R1), as well as 1-α hydroxylase, enabling conversion of vitamin D to both 25(OH)D₃ and 1,25(OH)₂ D₃ . Topical application of both vitamin D₃ and 1,25(OH)₂ D₃ to the gingiva of mice led to rapid inhibition of IL-1α expression, a prominent pro-inflammatory cytokine associated with inflammation, which also exhibited more than a 2-fold decrease from basal levels in OKF6/TERT1 cells upon 1,25(OH)₂ D₃ treatment, as determined by RNA-seq.

CONCLUSION

Vitamin D deficiency in mice contributes to PD, recapitulating the association seen in humans, and provides a unique model to study the development of PD. Vitamin D increases the activity of GEC against the invasion of periodontal pathogens and inhibits the inflammatory response, both in vitro and in vivo. GEC can convert inactive vitamin D to the active form in situ, supporting the hypothesis that vitamin D can be applied directly to the gingiva to prevent or treat periodontal disease.

Evaluation and comparison of Vitamin D receptors in periodontal ligament tissue of Vitamin D-deficient chronic periodontitis patients before and after supplementation of Vitamin D3

Background:

Vitamin D, an important hormone required by the body, exerts its biological effects through Vitamin D receptors (VDRs) present on target cells. Vitamin D is ineffective in tissues which lack VDR. Various tissues show the presence of VDRs. However, evidence for the presence of VDRs in human periodontal ligament tissue in fully erupted teeth in adults is lacking. The present study intends to evaluate the presence of VDRs in periodontal ligament (PDL) tissue and assess their response to serum Vitamin D3 levels in chronic periodontic patients.

Materials and Methods:

A total of 19 chronic periodontitis patients were enrolled in the study and tested for serum 25(OH)D3 levels. Deficient patients were supplemented with Vitamin D3. PDL tissue of these patients was isolated after tooth extraction before and after supplementation of Vitamin D3 and analyzed for the presence of VDR in PDL tissue by using enzyme-linked immunosorbent assay.

Results:

All the chronic periodontitis patients were found to be deficient in Vitamin D3. The mean serum 25(OH)D3 level before supplementation was 13.96 ng/mL which significantly increased to 35.12 ng/mL after supplementation of Vitamin D3 for 6 weeks. VDR analysis determined mean VDR conc. in PDL tissue to be -1.443 ng/mL, which increased to 2.38 ng/mL after supplementation. A concentration dependent correlation was seen between serum 25(OH)D3 levels and VDR conc. in PDL tissue after supplementation.

Conclusions:

The study determined Vitamin D Receptors (VDR) in PDL tissue after supplementation of Vitamin D. Thus in addition to the standard treatment modalities, Vitamin D3 supplementation would be an important factor for generation of adequate immune response.

Polymorphisms of the vitamin D receptor gene (FOKI, CDX2, and GATA) and susceptibility to chronic periodontitis in diabetic and non-diabetic individuals: A case-control study

AIM

The aim of the present study was to evaluate the distribution of single-nucleotide polymorphisms (SNP) (variants FOKI [rs2228570], CDX2 [rs47908762], and GATA [rs4516035]) in the vitamin D receptor in individuals with type 2 diabetes mellitus and chronic periodontitis (DM2 + CP), CP alone, and healthy individuals, and to investigate the relationship with susceptibility to CP.

METHODS

In total, 280 individuals (116 with DM2 + CP, 95 with CP alone, and 69 healthy individuals) were genotyped using real-time polymerase chain reaction with allele-specific probes. Significant differences (P < .05) were found among the groups with regard to socio-epidemiological variables (sex, marital status, income, smoking habit, and schooling) and clinical-epidemiological variables (age, number of teeth, probing depth, clinical attachment loss, gingival bleeding index, and visible plaque index).

RESULTS

The C allele was significantly more frequent among the healthy individuals (34.8%) than those with DM2 + CP (23.5%) (odds ratio [OR] = .58, 95% confidence interval [CI]: . 35-.94, P = .022). Likewise, the CC allele was significantly more frequent among healthy individuals (11.6%) than those with DM2 + CP (2.6%) (OR = .17, 95% CI: .03-.79, P = .015).

CONCLUSION

The results suggest that the presence of these variants could lead to a lower susceptibility to DM2 and CP. No other significant differences among groups were found for the other SNP investigated.

Human periodontal ligament cells exhibit no endotoxin tolerance upon stimulation with Porphyromonas gingivalis lipopolysaccharide

Background/Objectives

Endotoxin tolerance is characterized by a state of hyporesponsiveness after confrontation with endotoxins such as lipopolysaccharides (LPS) at low concentrations. The aim of this study was to investigate, whether pretreatment with Porphyromonas gingivalis leads to endotoxin tolerance induction and possible alterations in toll‐like receptor (TLR) 2‐ and 4‐induced response in human periodontal ligament cells (hPDLCs).

Material and Methods

Primary hPDLCs were pretreated with P. gingivalis (0.1 or 0.3 μg/mL) LPS for 24 hours and afterwards treated with one of the following stimuli: P. gingivalis LPS (1 μg/mL); TLR4 agonist Escherichia coli LPS (0.1 μg/mL; 1 μg/mL); TLR2 agonist Pam3CSK4 (0.1 μg/mL; 1 μg/mL). The protein expression of interleukin (IL)‐6, IL‐8 and monocyte chemotactic protein‐1 was analyzed with quantitative polymerase chain reaction and enzyme‐linked immunosorbent assay. Gene expression levels of TLR2 and TLR4 were determined by quantitative polymerase chain reaction.

Results

Pretreatment of cells with low concentrations of P. gingivalis LPS did not result in lower production of IL‐6, IL‐8 and monocyte chemotactic protein‐1 compared to control group. In some cases, pretreated cells exhibited lower gene expression levels of TLR2 and TLR4 compared to non‐pretreated cells.

Conclusion

The results of this study implicate that hPDLCs do not develop endotoxin tolerance. Furthermore, the amplitude of the inflammatory response shows no significant dependency on TLR2 and TLR4 expression levels.

Vitamin D Role in Prevention of Cancer: Overview

Vitamin D is the name given to a group of fat-soluble prohormones. Two major forms of Vitamin D that are important to humans are Vitamin D2 or ergocalciferol and Vitamin D3 or cholecalciferol. Vitamin D2 is made naturally by the body when the skin is exposed to ultraviolet radiation (in particular, ultraviolet B [UVB] radiation) in sunlight. Vitamin D2 and Vitamin D3 can also be commercially manufactured. The active form of Vitamin D in the body is 1,25-dihydroxyvitamin D or calcitriol, which can be made from either Vitamin D2 or Vitamin D3. Evidence suggests that Vitamin D helps in the prevention of various cancers such as breast cancer, colorectal cancer, prostate cancer, head and neck cancer, and other cancers. This review article briefs about the role of Vitamin D in the prevention of cancer.

Behavior of human periodontal ligament cells on dentin surfaces ablated with an ultra-short pulsed laser

This study aimed to evaluate the effects of an ultrashort pulsed laser (USPL) (1064 nm, 20 ps, 100 kHz) with different laser fluences (F, 4, 6, 8 J/cm²) and pulse overlaps (PO, 0, 50%) on human periodontal ligament cells (hPDLs) behavior. Dentin samples were ablated with USPL with different combinations of fluences and pulse overlaps; some samples were ablated with an Er:YAG laser (2940 nm, 150 µs, 100 mJ/pulse, 5 J/cm²) and some samples were ground with a carbide bur. Then hPDLs were grown on the samples after different treatments. Dentin morphology and cell adhesion were observed with SEM and gene expressions were measured by RT-PCR. The results showed dentin surfaces ablated with USPL when F = 4 J/cm², PO = 0, and F = 6 J/cm², PO = 0 were partially intact with obvious ridges and valleys and cells on these surfaces grew mostly along the valleys. USPL ablated surfaces in other groups were entirely ablated and cell cluster formation was observed. The RT-PCR results showed an upregulation of osteocalcin of cells grown on the dentin after some laser treatment. It can be concluded that USPL could improve the attachment and differentiation of hPDLs and thus potentially promote periodontal tissue regeneration.

Secretory leukocyte protease inhibitor regulates human periodontal ligament cell production of pro-inflammatory cytokines

Objective

Regulation of immune-like cell properties of periodontal ligament (PDL) cells is not understood. We investigate the importance of secretory leukocyte protease inhibitor (SLPI) for production of pro-inflammatory cytokines in human PDL cells.

Materials and methods

PDL cells were isolated from teeth extracted for orthodontic reasons. Cellular location of SLPI was investigated by immunocytochemistry. Cytokine transcript and protein expression were assessed by quantitative real-time RT-PCR and Western blotting. SLPI gene activity was knocked-down by siRNA. NF-κB signaling was assessed by measuring IκBα, and phosphorylated p65 and p105 protein expression.

Results

PDL cells showed cytoplasmic expression of SLPI. Cellular expression level of SLPI negatively correlated to LPS-induced stimulation of IL-6 and MCP-1. Both SLPI gene activity and protein were reduced by about 70% in PDL cells treated with SLPI siRNA compared to cells treated with non-coding construct. Treatment with SLPI siRNA was associated with up-regulation of both basal and LPS-stimulated IL-6, MCP-1 and TLRs mRNA expression. The up-regulation of MCP-1 transcript in SLPI siRNA-treated cells was confirmed on protein level. SLPI siRNA-treatment enhanced the phosphorylated NF-κB p105 protein expression.

Conclusions

SLPI regulates PDL cell pro-inflammatory cytokine expression and modulates NF-κB signaling, suggesting that SLPI governs the immune cell-like properties of PDL cells.

Effect of 1,25(OH)2 D3 and 20(OH)D3 on interleukin-1β-stimulated interleukin-6 and -8 production by human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Vitamin D-1,25(OH)₂ D₃ or 1,25D3-maintains healthy osseous tissue, stimulates the production of the antimicrobial peptide cathelicidin and has anti-inflammatory effects, but it can cause hypercalcemia. Evidence links diminished serum levels of 1,25D3 with increased gingival inflammation. Periodontitis progression is associated with increased local production of inflammatory mediators by immune cells and gingival fibroblasts. These include interleukin (IL)-6, a regulator of osteoclastic bone resorption, and the neutrophil chemoattractant IL-8, both regulated by signaling pathways, including NF-κB and MAPK/AP-1. The objectives were to determine the effects of 1,25D3 or a non-calcemic analog, 20-hydroxyvitamin D₃ -20(OH)D₃ or 20D3-on IL-1β-stimulated IL-6 and IL-8 production, and NF-κB and MAPK/AP-1 activation, by human gingival fibroblasts.

MATERIAL AND METHODS

Human gingival fibroblasts were incubated ± IL-1β, with or without exposure to 1,25D3 or 20D3. IL-6 and IL-8 in culture supernatants were measured by enzyme-linked immunosorbent assay. NF-κB (p65) and AP-1 (phospho-cJun) and were measured in nuclear extracts via binding to specific oligonucleotides. Data were analyzed using ANOVA and Scheffe's F procedure for post hoc comparisons.

RESULTS

IL-1β-stimulated IL-6 and IL-8 levels were both significantly inhibited (40%-60%) (P<.045) by 1,25D3, but not 20D3 (0%-15% inhibition, not statistically significant). Both 1,25D3 and 20D3 significantly and similarly inhibited IL-1β-stimulated nuclear levels of p65 and phospho-cJun (P<.02).

CONCLUSION

Reduction of the activation of NF-κB and AP-1 alone is not able to inhibit strongly the IL-1β stimulated IL-6 and IL-8 gene expression. 1,25D3 but not 20D3 may affect some of the many other factors/processes/pathways that in turn regulate the expression of these genes. However, the results suggest that topical application of ligands of the vitamin D receptor may be useful in the local treatment of periodontitis while reducing adverse systemic effects.

Serum levels of 25-hydroxyvitamin D are associated with periodontal disease

OBJECTIVES

Vitamin D plays an essential role in bone metabolism as well as in immunity. Hence, it might affect the development and extent of periodontal disease. The aim of this study was the assessment of 25-hydroxyvitamin D (25(OH)D) status in periodontal disease.

MATERIALS AND METHODS

Twenty-nine patients with severe periodontal disease and 29 healthy volunteers were recruited in this case-control-study. Serum 25(OH)D levels, Periodontal Probing Depth (PPD), Clinical Attachment Level (CAL), Bleeding on Probing (BOP), Body Mass Index (BMI), and current smoking status and smoking history (packyears) were assessed in all participants. Serum 25(OH)D levels were compared between controls and cases. Multivariable logistic regression was used to determine the odds ratio (OR) and 95 % confidence interval (CI) for periodontal disease in 25(OH)D deficient probands.

RESULTS

Patients with periodontal disease presented a significantly higher proportion of deficient 25(OH)D levels (i.e., <50 nmol/l) compared to healthy controls (48 vs. 14 % respectively). The adjusted OR for periodontal disease with vitamin D deficiency was 1.5 (95 % CI, 1.13-1.98). No correlation between serum 25(OH)D levels and CAL, PPD, and BOP in the group with periodontal disease was found.

CONCLUSIONS

In this case-control-study 25(OH)D deficiency is significantly associated with periodontal disease.

CLINICAL RELEVANCE

The assessment of vitamin D levels in patients presenting with periodontal disease seems advisable, as vitamin D deficiency might be involved in the onset and progression of periodontal disease.

Proliferation, behavior, and differentiation of osteoblasts on surfaces of different microroughness

OBJECTIVES

Titanium surface roughness is recognized as an important parameter influencing osseointegration. However, studies concerning the effect of well-defined surface topographies of titanium surfaces on osteoblasts have been limited in scope. In the present study we have investigated how Ti surfaces of different micrometer-scale roughness influence proliferation, migration, and differentiation of osteoblasts in-vitro.

METHODS

Titanium replicas with surface roughnesses (Ra) of approximately 0, 1, 2, and 4μm were produced and MG-63 osteoblasts were cultured on these surfaces for up to 5 days. The effect of surface micrometer-scale roughness on proliferation, migration in time-lapse microscopy experiments, as well as the expression of alkaline phosphatase, osteocalcin, vascular-endothelial growth factor (VEGF), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) were investigated.

RESULTS

Proliferation of MG-63 cells was found to decrease gradually with increasing surface roughness. However, the highest expression of alkaline phosphatase, osteocalcin and VEGF was observed on surfaces with Ra values of approximately 1 and 2μm. Further increase in surface roughness resulted in decreased expression of all investigated parameters. The cell migration speed measured in time-lapse microscopy experiments was significantly lower on surfaces with a Ra value of about 4μm, compared to those with lower roughness. No significant effect of surface roughness on the expression of OPG and RANKL was observed.

SIGNIFICANCE

Thus, surfaces with intermediate Ra roughness values of 1-2μm seem to be optimal for osteoblast differentiation. Neither proliferation nor differentiation of osteoblasts appears to be supported by surfaces with higher or lower Ra values.

Calcitriol Suppressed Inflammatory Reactions in IL-1β-Stimulated Human Periodontal Ligament Cells

Vitamin D has important roles on control of calcium and phosphate levels in the body. However, the role of vitamin D on the pathogenesis of periodontal disease is still uncertain. Therefore, we examined the effect of the hormonal form of vitamin D, calcitriol, on inflammatory responses of human periodontal ligament cells (HPDLC). We detected vitamin D receptor expression in non-stimulated HPDLC. Calcitriol inhibited interleukin (IL)-6, IL-8, CC chemokine ligand (CCL) 20, CXC chemokine ligand (CXCL) 10, and matrix metalloproteinase (MMP)-3 release from IL-1β-stimulated HPDLC. Tissue inhibitor of metalloproteinase (TIMP)-1 production did not change by calcitriol. Moreover, we found c-jun N-terminal kinase (JNK) phosphorylation and IκB-α degradation in IL-1β-stimulated HPDLC were inhibited by calcitriol, and JNK and nuclear factor (NF)-κB inhibitors could decrease IL-6, IL-8, CCL20, CXCL10, and MMP-3 productions in IL-1β-treated HPDLC. These findings suggest that vitamin D could modulate inflammatory response in periodontal tissues.

C/EBP β Mediates Endoplasmic Reticulum Stress Regulated Inflammatory Response and Extracellular Matrix Degradation in LPS-Stimulated Human Periodontal Ligament Cells

Periodontitis is an oral inflammatory disease that not only affects the integrity of local tooth-supporting tissues but also impacts systemic health. A compositional shift in oral microbiota has been considered as the main cause of periodontitis; however, the potential mechanism has not been fully defined. Herein, we investigated the role of CCAAT/enhancer-binding protein β (C/EBP β), a member of the C/EBP family of transcription factors, in human periodontal ligament cells (hPDLCs) exposed to Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS). RT-PCR and Western blotting analysis showed that the expression of C/EBP β was significantly increased in hPDLCs stimulated with LPS stimuli. Overexpression of C/EBP β by the recombinant adenoviral vector pAd/C/EBP β markedly increased the expression of the pro-inflammatory cytokines IL-6 and IL-8, and matrix metalloproteinases (MMP)-8 and -9 in hPDLCs in response to LPS. Furthermore, the activation of endoplasmic reticulum (ER) stress was confirmed in LPS-stimulated hPDLCs by measuring the expression of the ER stress marker molecules protein kinase-like ER kinase (PERK), eIF2α, GRP78/Bip, and C/EBP homologous protein (CHOP). The ER stress inhibitor salubrinal repressed, but inducer tunicamycin enhanced, the production of IL-6, IL-8, MMP-8, and MMP-9 in hPDLCs. Additionally, ER stress inducer tunicamycin significantly increased the expression level of C/EBP β in hPDLCs. Blocking of C/EBP β by siRNA resulted in a significant decrease in the secretion of IL-6 and IL-8 and expression of MMP-8 and MMP-9 induced by tunicamycin treatment in hPDLCs. Taken together, ER stress appears to play a regulatory role in the inflammatory response and extracellular matrix (ECM) degradation in hPDLCs in response to LPS stimuli by activating C/EBP β expression. This enhances our understanding of human periodontitis pathology.

Effects of 1,25-dihydroxyvitamin D3 on Macrophage Cytokine Secretion Stimulated by Porphyromonas gingivalis

Vitamin D is known to be closely associated with periodontitis; however, its exact mechanisms remain to be clarified. The present study aimed to investigate the influence of 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) on Porphyromonas gingivalis (Pg)-stimulated cytokine production and the involved signaling pathways in macrophages. The main observation was that 1,25(OH)₂D₃ inhibited Pg-induced interleukin (IL)-6 cytokine expression but up-regulated the expression of anti-inflammatory cytokine IL-10. Further analyses showed that 1,25(OH)₂D₃ decreased p38 mitogen-activated protein kinase (MAPK) and extracellular signal regulated kinase (ERK)1/2 phosphorylation. Inhibited phosphorylation of p38 MAPK and ERK1/2 was associated with decreased level of IL-6 expression, but was not related to increased level of IL-10 expression in macrophages stimulated with Pg. These results suggest that 1,25(OH)₂D₃ might exert its anti-inflammatory effects on Pg-stimulated macrophages partly through its inhibitory effect on the p38 MAPK and ERK1/2 signaling pathway.

Protection against oxidative stress by vitamin D in cone cells

Photoreceptor degeneration (PD) refers to a group of heterogeneous outer retinal dystrophies characterized by the death of photoreceptors. Both oxidative stress and inflammation are involved in the pathogenesis of PD. We investigate whether vitamin D has a potential for the treatment of PD by evaluating the anti-oxidative stress and anti-inflammatory properties of the active form of vitamin D3 , 1,α, 25-dihydroxyvitamin D3 , in a mouse cone cell line, 661W. Mouse cone cells were treated with H2 O2 or a mixture of H2 O2 and vitamin D; cell viability was determined. The production of reactive oxygen species (ROS) in treated and untreated cells was measured. The expression of key anti-oxidative stress and inflammatory genes in treated and untreated cells was determined. Treatment with vitamin D significantly increased cell viability and decreased ROS production in 661W cells under oxidative stress induced by H2 O2 . H2 O2 treatment in 661W cells can significantly down-regulate the expression of antioxidant genes and up-regulate the expression of neurotoxic cytokines. Vitamin D treatment significantly reversed these effects and restored the expression of antioxidant genes. Vitamin D treatment also can block H2 O2 induced oxidative damages. The data suggested that vitamin D may offer a therapeutic potential for patients with PD.

Effect of tyrosine-rich amelogenin peptide on behavior and differentiation of endothelial cells

Background

Enamel matrix derivative (EMD) is an effective biomaterial for periodontal tissue regeneration and might stimulate angiogenesis. Tyrosine-rich amelogenin peptide (TRAP) is present in EMD and is thought to contribute in its biological activity. In the present study, we investigated the effect of chemically synthesized TRAP on proliferation, migration, angiogenic structure formation, and differentiation of human umbilical vein endothelial cells (HUVECs) in vitro.

Material and methods

The effects of TRAP isolated from EMD and chemically synthesized TRAP on proliferation/viability, migration, and angiogenic structure formation were investigated. Expression of angiopoietin-2 (ang-2), von Willebrand factor (vWF), E-selectin, intracellular adhesion molecules 1 (ICAM-1), vascular endothelial growth factor (VEGF) receptors FMS-like tyrosine kinase 1 (FLT-1), and kinase insert domain receptor (KDR) was measured on both messenger RNA (mRNA) and protein levels.

Results

The proliferation/viability of HUVECs was inhibited by TRAP at concentration of 100 μg/ml and slightly stimulated by EMD at similar concentration. Both EMD and TRAP stimulated endothelial cell migration in microchemotaxis chamber. The effect of both TRAP preparations on the migration was significantly higher than that of EMD. All substances stimulated formation of angiogenic structure in vitro. The expression of ICAM-1, E-selectin, FLT-1, KDR, and vWF was significantly increased by both TRAP and EMD at a concentration 50 μg/ml. The expression of ang-2 was not affected by TRAP but was significantly increased by EMD.

Conclusion

Our in vitro study shows that TRAP confer the most effects of EMD on the endothelial cells.

Clinical relevance

TRAP might be used as a basis for development of new approaches for periodontal regeneration.

Evaluation of the gingival inflammation in pregnancy and postpartum via 25-hydroxy-vitamin D3, prostaglandin E2 and TNF-α levels in saliva

BACKGROUND

Physiological changes and immunological modifications occur during pregnancy. The clinical and biological features of periodontal infections are affected by pregnancy. The aim of the present study was to evaluate saliva levels of 25-hydroxy-vitamin D3 (25(OH)D3), prostaglandin E2 (PGE2) and TNF-alpha (TNF-α) in pregnancy, postpartum and non-pregnant controls.

METHODS

Whole saliva samples together with full-mouth clinical periodontal recordings were obtained from 59 pregnant, 47 post partum and 70 systemically healthy non-pregnant women. Groups were also evaluated according to the periodontal health status. 25(OH)D3, PGE2 and TNF-α levels in the saliva samples were determined by enzyme-linked immunoassays. Data were statistically tested by nonparametrical tests.

RESULTS

Saliva TNF-α and PGE2 levels were significantly lower and 25(OH)D3 levels were significantly higher in the pregnant group than postpartum group (p<0.0001). Saliva TNF-α and 25(OH)D3 levels were significantly higher and PGE2 levels were significantly lower in the control group than postpartum group (p<0.0001). In the pregnant healthy, gingivitis and periodontitis groups saliva TNF-α levels were significantly lower than postpartum and control counterparts (p<0.0001, p=0.032, p=0.003 and p=0.013; p=0.027; p=0.007, respectively). In control healthy, gingivitis and periodontitis groups saliva 25(OH)D3 levels were significantly higher than the postpartum counterparts (p<0.0001, p<0.0001, p=0.002, respectively). In the control healthy and gingivitis groups saliva 25(OH)D3 levels were significantly higher than pregnant healthy and gingivitis (p<0.0001).

CONCLUSIONS

In conclusion, within the limits of the present study it seems that pregnancy have an effect on parameters in saliva in relation to the periodontal status of the women. Further studies are required for better understanding of the impact of periodontal diseases on pregnancy or otherwise.

Vitamin D inhibits the growth of and virulence factor gene expression by Porphyromonas gingivalis and blocks activation of the nuclear factor kappa B transcription factor in monocytes

BACKGROUND AND OBJECTIVE

Increasing evidence suggests that 1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), a fat-soluble secosteroid hormone, has a positive impact on periodontal health through diverse mechanisms. The present study was aimed at investigating the effect of 1,25(OH)2 D3 on the growth of and virulence factor gene expression by the periodontopathogenic bacterium Porphyromonas gingivalis. The effect of 1,25(OH)2 D3 on P. gingivalis-mediated activation of nuclear factor kappa B (NF-κB) transcription factor in monocytes was also assessed.

MATERIAL AND METHODS

A broth microdilution assay was used to determine the antibacterial activity of 1,25(OH)2 D3 . The modulation of virulence factor gene expression in P. gingivalis was assessed by quantitative reverse transcription-polymerase chain reaction. NF-κB activation was assessed using a human monocytic cell line stably transfected with a luciferase reporter containing NF-κB binding sites.

RESULTS

Minimal inhibitory concentrations of 1,25(OH)2 D3 against P. gingivalis ranged from 3.125 to 6.25 μg/mL. Moreover, a partial synergistic effect was observed when 1,25(OH)2 D3 was used in association with metronidazole. 1,25(OH)2 D3 attenuated the virulence of P. gingivalis by reducing the expression of genes coding for important virulence factors, including adhesins (fimA, hagA and hagB) and proteinases (rgpA, rgpB and kgp). 1,25(OH)2 D3 dose-dependently prevented P. gingivalis-induced NF-κB activation in a monocyte model.

CONCLUSION

Our study suggested that 1,25(OH)2 D3 selectively inhibits the growth of and virulence factor gene expression by P. gingivalis, in addition to attenuating NF-κB activation by this periodontopathogen. This dual action on P. gingivalis and the inflammatory response of host cells may be of particular interest with a view to developing a novel and inexpensive preventive/therapeutic strategy.

Vitamin D and chronic hepatitis C: effects on success rate and prevention of side effects associated with pegylated interferon-α and ribavirin

Chronic hepatitis C (CHC) is one of the most common causes of liver diseases worldwide, affecting 3% of the world population and 3 to 4 million people acquire new infection annually. Despite the recent introduction of novel antiviral drugs for the treatment of CHC, these drugs are expensive and the access to them is not an option for many patients. Hence, the traditional therapy by pegylated interferon-α (Peg-IFN-α) and ribavirin may still have a role in the clinical management of CHC especially in developing countries. However, this standard therapy is associated with several severe extra-hepatic side effects and the most common adverse events are hematological abnormalities and thyroid disorders and they could result in dose reduction and/or termination of therapy. Vitamin D has been shown to be a key regulatory element of the immune system, and its serum concentrations correlate with the severity of liver damage and the development of liver fibrosis/cirrhosis. Furthermore, supplementation with vitamin D with Peg-IFN-α based therapy for the treatment of CHC could be beneficial in increase the response rate to Peg-INF-α based therapy. Vitamin D has also been shown to regulate the thyroid functions and the process of erythropoiesis. This review appraises the data to date researching the role of vitamin D during the treatment of CHC and the potential role of vitamin D in preventing/treating Peg-IFN-α induced thyroiditis and anemia during the course of treatment.

Focal adhesion kinase activation is required for TNF-α-induced production of matrix metalloproteinase-2 and proinflammatory cytokines in cultured human periodontal ligament fibroblasts

Since focal adhesion kinase (FAK) was proposed as a mediator of the inflammatory response, we have investigated the role of this molecule in the release of inflammatory cytokines by cultured human periodontal ligament fibroblasts (HPDLFs), cells that are thought to be important in the patient's response to periodontal infection. Human periodontal ligament fibroblasts were stimulated by tumor necrosis factor alpha (TNF-α) and its effects on interleukin (IL)-6 and IL-8 release were measured by ELISA. Expression of matrix metalloproteinase 2 (MMP-2) protein was analysed by western blotting. The levels of IL6, IL8, and MMP2 mRNA were evaluated by real-time PCR. Tumor necrosis factor alpha dose-dependently induced the phosphorylation of FAK, whereas small interfering FAK (siFAK) inhibited TNF-α-induced FAK phosphorylation. Tumor necrosis factor alpha also stimulated the production of IL-6, IL-8, and MMP-2 in a dose-dependent manner. Knockdown of FAK significantly suppressed TNF-α-induced expression of IL6 and IL8 mRNA and release of IL-6 and IL-8 protein in HPDLFs. Similarly, MMP-2 down-regulation was significantly prevented by siFAK. Our results strongly suggest that knockdown of FAK can decrease the production of TNF-α-induced IL-6, IL-8, and MMP-2 in HPDLFs. These effects may help in understanding the mechanisms that control expression of inflammatory cytokines in the pathogenesis of periodontitis.

Effect of different enamel matrix derivative proteins on behavior and differentiation of endothelial cells

OBJECTIVES

Enamel matrix derivative (EMD) is an effective biomaterial for periodontal tissue regeneration and might stimulate angiogenesis. In order to clarify mechanisms underlying its biological activity, we separated two EMD fractions with different molecular weight protein components and investigated their effects on human umbilical vein endothelial cells (HUVECs) in vitro.

METHODS

Fraction Low-Molecular Weight (LMW) included proteins with a molecular weight (M.W.)<8kDa. Fraction LMW-depleted included proteins with M.W.>8kDa and lower than approximately 55kDa. The effect of EMD fractions on proliferation/viability, apoptosis, migration and expression of angiopoetin-2 (ang-2), von Willebrand factor (vWF), E-selectin, intracellular adhesion molecules 1 (ICAM-1), vascular endothelial growth factor (VEGF) receptors Flt-1 and KDR was investigated.

RESULTS

The proliferation/viability of HUVECs was inhibited by both LMW and LMW-depleted at concentrations 100μg/ml, whereas EMD slightly increased cell proliferation/viability. The expression of all investigated proteins was up-regulated by EMD. However, differences in the effect of EMD fractions on the protein expression were observed. The effect of LMW-depleted on the expression of ICAM-1 and E-selectin was markedly higher compared to LMW. In contrast, the expression of vWF and VEGF receptors Flt-1 and KDR was primarily affected LMW than by LMW depleted. The expression of ang-2 was not influenced by LMW and LMW-depleted. HUVECs migration was stimulated more strongly by LMW than by EMD and LMW-depleted.

CONCLUSION

Our in vitro study shows that the proteins composing EMD have different and specific biological activities and consequently have the ability to cover different aspects of EMD's biological and clinical effects.

Low vitamin D levels are associated with both iron deficiency and anemia in children and adolescents

BACKGROUND

We aimed to examine the association between vitamin D deficiency and anemia in a nationally representative sample of Korean children and adolescents.

METHODS

Cross-sectional data on 2526 children and adolescents aged 10-20 years from the Korea National Health and Nutrition Examination Survey-V (2010-2012) were used. Anemia was defined according to specifications of the World Health Organization. Iron deficiency was defined as serum ferritin level of <12 ng/mL and transferrin saturation (TSAT) <16%.

RESULTS

The prevalence of vitamin D deficiency in Korean children and adolescents was high especially in female (35.7% vs. 50.9%, P < 0.001). The prevalence of anemia was also higher in female (1.1% vs. 6.8%; P < 0.001). In logistic regression, risk factors for anemia were female sex, old age, post-menarche, low household income, vitamin D deficiency, and iron deficiency. The Odds Ratio for anemia, iron deficiency and iron deficiency anemia (IDA) in subjects with vitamin D deficiency (<15 ng/mL) were 1.81(95% CI, 1.13-2.88), 1.94(95% CI, 1.27-2.97), and 2.26 (95% CI, 1.20-4.24) after controlling for other risk factors. However, after examining the sexes separately, only female subjects showed statistical significance. After further controlling for iron deficiency, the risk of anemia was not significant (P = 0.261).

CONCLUSIONS

Vitamin D deficiency is associated with increased risk of anemia, especially iron deficiency anemia, in healthy female children and adolescents. However, the association is attenuated after adjustment for iron deficiency. Further studies are needed to determine whether vitamin D deficiency is the cause of anemia, or bystander of nutritional deficiency which cause iron deficiency.

Behavior of osteoblasts on TI surface with two different coating designed for orthodontic devices

In the present study we coated Ti surfaces with polytetrafluorethylene (PTFE) and titanium nitride (TiN) and investigated in vitro the behavior of osteoblasts on these surfaces. MG-63 osteoblasts were cultured on titanium discs with different surface treatment: uncoated Ti6Al4V, TiN-coated, PTFE-coated. Cell viability/proliferation was detected by MTT assay. Gene-expression levels of alkaline phosphatase (ALP), osteocalcin (OC), type I collagen, receptor activator of nuclear factor-kappa-B ligand (RANKL), and osteoprotegerin (OPG) were determined by qPCR. Cell behavior on different surfaces was observed by time-lapse microscopy. Cells grown on PTFE-coated Ti surface exhibited delayed surface attachment and decreased proliferation after 48 h. However, after 168 h of culture cells grown on PTFE-coated surface exhibited higher viability/proliferation, higher expression levels of ALP and OC, and higher OPG/RANKL ratio compared to uncoated surface. No effect of TiN-coating on any investigated parameter was found. Our results shows that PTFE coating exhibits no toxic effect on MG-63 cells and slightly stimulates expression of several genes associated with osteogenesis. We propose that PTFE coating could be considered as a possible choice for a surface treatment of temporary skeletal anchorage devices in orthodontics.

1α,25-dihydroxyvitamin D3 promotes osteogenic activity and downregulates proinflammatory cytokine expression in human periodontal ligament cells

BACKGROUND AND OBJECTIVE

The aim of this study was to assess the impact of 1α,25-dihydroxyvitamin D3 (vitamin D3) on osteogenic and inflammatory properties of human periodontal ligament (PDL) cells and investigate underlying mechanisms.

MATERIAL AND METHODS

Human PDL cells, obtained from four subjects, were stimulated with vitamin D3 for 4-48 h. The bone markers osteopontin and osteocalcin and proinflammatory cytokine/chemokine expression was determined by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Cytokine and chemokine expression was determined after stimulation with the inflammation promoter lipopolysaccharide (LPS) in the presence or absence of vitamin D3. Alkaline phosphatase activity was assessed using p-nitrophenylphosphate substrate.

RESULTS

Treatment with 30 ng/mL of vitamin D3, corresponding to an optimal plasma concentration of vitamin D, for 24 h had no effect on PDL cell number and morphology but increased PDL cell osteopontin and osteocalcin mRNA expression by about 70 and 40%, respectively, and, moreover, treatment with vitamin D3 for 48 h enhanced PDL cell alkaline phosphatase activity by about two times showing that vitamin D3 exerts pro-osteogenic effects in human PDL cells. Stimulation with LPS (1 μg/mL) for 4 h increased PDL cell interleukin (IL)-6 cytokine and chemokine ligand 1 (CXCL1) chemokine mRNA expression several fold. The LPS-induced increase in IL-6 and CXCL1 transcripts was attenuated by vitamin D3 (30 ng/mL). Treatment with vitamin D3 (3-300 ng/mL) for 24 h reduced the LPS-evoked increase in PDL cell IL-6 protein by about 50%. Vitamin D3 (30 ng/mL) had no effect on LPS-induced IL-1β and MCP-1 mRNA expression.

CONCLUSIONS

Vitamin D3 promotes osteogenic differentiation but also downregulates inflammation promoter-induced IL-6 cytokine and CXCL1 chemokine expression in human PDL cells, suggesting that vitamin D3 both stimulates bone regeneration and antagonizes inflammation in human periodontal tissue.