Effects of Low-Dose Doxycycline and Bisphosphonate Clodronate on Alveolar Bone Loss and Gingival Levels of Matrix Metalloproteinase-9 and Interleukin-1β in Rats With Diabetes: A Histomorphometric and Immunohistochemical Study

Effects of Coriander on the Repair Process of Experimentally-induced Periodontitis in Rats

The aim of this study was to evaluate the effects of Coriandrum sativum L. (CSL) seed extract on gingival levels of antioxidant enzymes, pro-inflammatory cytokines and on alveolar bone and attachment levels after experimental periodontitis induction in rats and compare it with low-dose doxycycline (LDD). Forty adult male Wistar Albino rats were divided randomly into 5 groups as follows: 1 = periodontally healthy (control); 2 = periodontitis; 3 = periodontitis + CSL (32 mg/kg); 4 = periodontitis + CSL (200 mg/kg); and 5 = periodontitis + LDD (6 mg/kg). Gingival superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated by enzyme-linked immunosorbent assay. The presence of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1βeta (IL-1β) immunoreactivity was detected immunohistochemically. Alveolar bone area in the furcation space (ABA), alveolar bone loss (ABL), and attachment loss (AL) were evaluated histomorphometrically. The SOD level was lower in group 5 than in groups 2, 3, and 4. The IL-1β level was highest in group 4. The TNF-α level was statistically higher in groups 2 and 4 than in groups 1, 3, and 5. The IL-6 level was highest in group 4. Its level was higher in groups 2 and 3 than in group 5. ABA was less in groups 2, 3, and 4 compared to groups 1 and 5. ABL was less in group 5 than in groups 2, 3, and 4. AL was greater in group 4 than in group 5. The use of 200 mg/kg CSL showed a pro-inflammatory effect and IL-1β and TNF-α levels decreased after 32 mg/kg CSL application in the treatment of periodontitis.

Recent progress in bone-repair strategies in diabetic conditions

Bone regeneration following trauma, tumor resection, infection, or congenital disease is challenging. Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia. It can result in complications affecting multiple systems including the musculoskeletal system. The increased number of diabetes-related fractures poses a great challenge to clinical specialties, particularly orthopedics and dentistry. Various pathological factors underlying DM may directly impair the process of bone regeneration, leading to delayed or even non-union of fractures. This review summarizes the mechanisms by which DM hampers bone regeneration, including immune abnormalities, inflammation, reactive oxygen species (ROS) accumulation, vascular system damage, insulin/insulin-like growth factor (IGF) deficiency, hyperglycemia, and the production of advanced glycation end products (AGEs). Based on published data, it also summarizes bone repair strategies in diabetic conditions, which include immune regulation, inhibition of inflammation, reduction of oxidative stress, promotion of angiogenesis, restoration of stem cell mobilization, and promotion of osteogenic differentiation, in addition to the challenges and future prospects of such approaches.

Effect of systemic bisphosphonate administration on patients with periodontal disease: a systematic review and meta-analysis protocol

INTRODUCTION

Periodontal disease is a chronic oral infectious disease affecting adults worldwide as well as a lifestyle-related disease related to diabetes. Bisphosphonate is a drug often taken by patients with osteoporosis; however, it reportedly can cause jawbone necrosis. Due to its mechanism of action on bone tissue, bisphosphonate has been used topically on periodontal tissue to treat periodontal disease. However, the long-term systemic effects of bisphosphonates on periodontal tissues are unclear. This paper describes a protocol evaluating the effects of systemic bisphosphonate administration to prevent periodontal tissue destruction in patients with periodontal disease. No systematic review has attempted to summarise the evidence for systemic bisphosphonates in periodontal therapy. The results of the proposed systematic review will inform the practice and design of future clinical trials.

METHODS AND ANALYSIS

This paper describes a protocol for a systematic review of the relevant published analytic research using an aggregative thematic approach according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. Two authors will perform a comprehensive search for studies on Medline/PubMed, Scopus, Embase, LILACS and the Cochrane Central Register of Controlled Trials databases. Abstract screening, full-text screening and data extraction will be performed independently by two authors. A meta-analysis will be conducted as appropriate.

ETHICS AND DISSEMINATION

The protocol of this systematic review will be provided in a peer-reviewed journal. Formal ethics approval is not necessary because researchers will not identify individuals in the report.

PROSPERO REGISTRATION NUMBER

CRD42020212698 (http://www.crd.york.ac.uk/PROSPERO/).

Effects of local administration of tiludronic acid on experimental periodontitis in diabetic rats

BACKGROUND

Tiludronic acid (TIL) presents antiresorptive and anti-inflammatory properties and has not been evaluated in the periodontitis-diabetes mellitus (DM) association to date, to the best knowledge of the authors. This study evaluates effects of local administration of TIL on experimental periodontitis (EP) in rats with streptozotocin-induced DM.

METHODS

Thirty-two animals (Rattus norvegicus albinus, Wistar) were divided into groups DM/C (Control), DM/EP, DM/EP/TIL1, and DM/EP/TIL3. In EP groups, a ligature was placed around mandibular first molars. In groups DM/EP/TIL1 and DM/EP/TIL3, TIL solutions (1 and 3 mg/kg, respectively) were injected into the gingival tissue of mandibular molars every other day for 10 days, until euthanasia. Periodontal tissues were analyzed by microcomputed tomography (micro-CT), histomorphometry, immunohistochemistry (tartrate-resistant acid phosphatase [TRAP], receptor activator of nuclear factor-κB ligand [RANKL], osteoprotegerin, cleaved caspase 3), and quantitative reverse transcription-polymerase chain reaction (interleukin [IL]-1β, vascular endothelial growth factor [VEGF]).

RESULTS

In micro-CT analyses, groups DM/EP/TIL1 and DM/EP/TIL3 presented reduced alveolar bone resorption (P < 0.05). Group DM/EP/TIL3 presented decreased attachment loss (P < 0.05). The amount of TRAP-positive multinucleated cells was decreased in TIL groups (P < 0.05). Group DM/EP/TIL3 presented a lower immunolabeling pattern for RANKL (P < 0.05). TIL treatment decreased genic expression of IL-1β, and in group DM/EP/TIL3, expression of VEGF was increased (P < 0.05).

CONCLUSION

Local administration of TIL promoted a protective effect against tissue destruction in EP in diabetic rats, and the dosage of 3 mg/kg of TIL promoted the best results regarding its antiresorptive and anti-inflammatory effects.

Influence of clodronate and compressive force on IL-1ß-stimulated human periodontal ligament fibroblasts

OBJECTIVES

The aim of this study was to investigate in vitro the effect of clodronate on interleukin-1ß (IL-1ß)-stimulated human periodontal ligament fibroblasts (HPdLFs) with the focus on inflammatory factors of orthodontic tooth movement with and without compressive force.

MATERIALS AND METHODS

HPdLFs were incubated with 5 μM clodronate and 10 ng/mL IL-1ß. After 48 h, cells were exposed to 3 h of compressive force using a centrifuge. The gene expression of cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), matrix metalloproteinase 8 (MMP-8), and the tissue inhibitor of MMP (TIMP-1) was analyzed using RT-PCR. Prostaglandin E2 (PGE-2), IL-6, and TIMP-1 protein syntheses were quantified via ELISA.

RESULTS

Compressive force and IL-1ß induced an overexpression of COX-2 gene expression (61.8-fold; p < 0.05 compared with control), diminished by clodronate (41.1-fold; p < 0.05 compared with control). Clodronate slowed down the compression and IL-1ß induced IL-6 gene expression (161-fold vs. 85.6-fold; p < 0.05 compared with control). TNF-α was only slightly affected without statistical significance. Clodronate reduced IL-1ß-stimulated MMP-8 expression with and without compressive force. TIMP-1 on gene and protein level was downregulated in all groups. Analyzing the MMP-8/TIMP-1 ratio, the highest ratio was detected in IL-1ß-stimulated HPdLFs with compressive force (21.2-fold; p < 0.05 compared with control). Clodronate diminished IL-1ß-induced upregulation of MMP-8/TIMP-1 ratio with (11.5-fold; p < 0.05 compared with control) and without (12.5-fold; p < 0.05 compared with control) compressive force.

CONCLUSION

Our study demonstrates a slightly anti-inflammatory effect by clodronate under compressive force in vitro. Additionally, the periodontal remodeling presented by the MMP-8/TIMP-1 ratio seems to be diminished by clodronate.

CLINICAL RELEVANCE

Reduction of pro-inflammatory factors and reduction of periodontal remodeling might explain reduced orthodontic tooth movement under clodronate intake.

Effects of glucocorticoid-induced osteoporosis on bone tissue of rats with experimental periodontitis

OBJECTIVE

To evaluate the effects of osteoporosis induced by glucocorticoid (GIOP) on bone tissue of rats with experimental periodontitis (EP).

DESIGN

48 male Wistar rats divided into groups: Naïve, EP, GIOP and GIOP+EP. Rats of GIOP and GIOP+EP groups received 7mg/kg of dexamethasone intramuscularly once a week for 5 weeks. Following, EP and GIOP+EP groups were subjected to ligature-induced periodontitis. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic, radiographic, micro-tomographic and microscopic analysis of alveolar bone loss (ABL). Blood samples were collected for determination of bone-specific alkaline phosphatase (BALP) levels and the right femurs were removed for radiographic and biomechanical analysis.

RESULTS

EP caused ABL and reduced BALP levels (p<0,05), but it did not change the architecture or biomechanics of femur, compared to Naïve. GIOP did not cause ABL, but it significantly decreased alveolar bone mineral density (ABMD), bone percentage and trabecular thickness (Tb.Th) and increased alveolar bone porosity (p<0.05) and significantly reduced BALP serum levels, as well as radiographic density and Young's module of femur, compared to Naïve. There was a greater ABL in group GIOP+EP when compared to EP (p<0.05). GIOP+EP caused a greater decrease on ABMD, Tb.Th, bone percentage and increased bone porosity (p<0.05) and also presented a significant reduction in BALP levels (p<0.05), in radiographic density and in Young's module of femur compared to EP (p<0.05).

CONCLUSIONS

GIOP can potentiate the destructive effects of EP on alveolar bone and alter the systemic bone loss, by promoting bone resorption and reducing osteoblast activity.

Efficacy of bisphosphonate as an adjunct to nonsurgical periodontal therapy in the management of periodontal disease: a systematic review

AIMS

The aim of this systematic review was to assess the efficacy of bisphosphonate therapy as an adjunct to scaling and root planing (SRP) in the management of periodontitis.

METHODS

Databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and Cochrane Oral Health Group Trials Register databases) were searched up to and including July 2016. The primary outcome was probing depth (PD), and the secondary outcomes were changes in clinical attachment level (CAL) and bone defect (BD) fill. The mean differences (MD) of outcomes and 95% confidence intervals (CI) for each variable were calculated using random effect model.

RESULTS

Eight clinical studies were included. Seven studies used alendronate as an adjunct to SRP; of these, four studies used topical application and three used oral alendronate. Considering the effects of adjunctive bisphosphonates as compared to SRP alone, a high degree of heterogeneity for PD (Q value = 39.6, P < 0.0001, I²  = 87.38%), CAL (Q value = 13.65, P = 0.008, I²  = 70.71%), and BD fill (Q value = 53.26, P < 0.0001, I²  = 92.49%) was noticed among both the groups. Meta-analysis showed a statistically significant PD reduction (MD = -1.18, 95% CI = -1.91 to -0.44, P = 0.002), CAL gain (MD = -0.69, 95% CI = -1.20 to -0.18, P = 0.008) and BD fill (MD = -2.36, 95% CI = -3.64 to -1.08, P < 0.001) for SRP + bisphosphonate treatment vs. SRP alone.

CONCLUSIONS

Adjunctive bisphosphonate therapy appears to be effective in managing periodontitis, however, due to the potential risk of osteonecrosis of the jaws and short-term follow-up of the studies, their clinical application is debatable.

The Effect of Local Delivery Doxycycline and Alendronate on Bone Repair

The aim of the present study was to investigate the local effect of 10% doxycycline and 1% alendronate combined with poly(lactic-co-glycolic acid) (PLGA) on bone repair. Thirty rats were divided into three groups, as follows: control group (CG), drug group (DG), and vehicle-PLGA group (VG). Bone defect was created in the right femur and filled with the following: blood clot (CG); PLGA gel, 10% doxycycline and 1% alendronate (DG); or vehicle-PLGA (VG). The animals were euthanized 7 or 15 days after surgery. Bone density, bone matrix and number of osteoclasts were quantified. At 7 days, the findings showed increased density in DG (177.75 ± 76.5) compared with CG (80.37 ± 27.4), but no difference compared with VG (147.1 ± 41.5); no statistical difference in bone neoformation CG (25.6 ± 4.8), VG (27.8 ± 4), and DG (18.9 ± 7.8); and decrease osteoclasts in DG (4.6 ± 1.9) compared with CG (26.7 ± 7.4) and VG (17.3 ± 2.7). At 15 days, DG (405.1 ± 63.1) presented higher density than CG (213.2 ± 60.9) and VG (283.4 ± 85.8); there was a significant increase in percentage of bone neoformation in DG (31.5 ± 4.2) compared with CG (23 ± 4), but no difference compared with VG (25.1 ± 2.9). There was a decreased number of osteoclasts in DG (20.7 ± 4.7) and VG (29.5 ± 5.4) compared with CG (40 ± 9.4). The results suggest that the association of 10% doxycycline and 1% alendronate with PLGA-accelerated bone repair.

Antioxidant response of osteoblasts to doxycycline in an inflammatory model induced by C-reactive protein and interleukin-6

Objectives: Investigation of osteoblastic responses to oxidative stress, induced by C-reactive protein (CRP) and IL-6 and ameliorating effects of doxycycline (Dox); using assays for 5-alpha dihydrotestosterone (DHT) as an antioxidant marker of healing. IL-6 and CRP are risk markers of periodontitis and prevalent comorbidities in periodontitis subjects. Methods: Confluent monolayer cultures of osteoblasts were incubated with radiolabelled testosterone (14C-T) as substrate, in the presence or absence (Control) of pre-determined optimal concentrations of CRP, IL-6, Dox; alone and in combination (n=8) for 24h in MEM. The eluent was solvent-extracted for steroid metabolites. They were separated using TLC in a benzene/ acetone solvent system 4:1 v/v; and quantified using radioisotope scanning. The identity of formed metabolites was confirmed using the mobility of cold standards added to the samples and disclosed in iodine. Further confirmation of the authenticity of DHT was carried out by combined gas chromatrography-mass spectrometry, after derivatization to pentafluorobenzyloxime trimethyl silyl ether. Results: The yields of DHT from 14C-testosterone showed 2-fold and 1.8-fold- inhibition in response to IL-6 and CRP respectively and 28% stimulation in response to Dox, via the 5-alpha reductase pathway. The combination of IL-6 + CRP showed a 2-fold reduction in the yields of DHT, elevated to control values when combined with Dox (n=8; p<0.001). Yields of 4-androstenedione showed an inverse relationship to those of DHT, in response to the agents tested, in keeping with the 17-beta hydroxysteroid dehydrogenase pathway. Conclusions: Inhibition of DHT synthesis in osteoblasts by IL-6 and CRP was overcome by doxycycline. Oxidative actions of IL-6 and CRP; and antioxidant actions of Dox are reinforced by the metabolic yields of DHT in response to agents tested. Using a novel metabolically active model allows closer extrapolation to in vivo conditions; in the context of adjunctive therapeutic applications for periodontitis and prevalent comorbidities.

The histopathological and morphometric investigation of the effects of systemically administered boric acid on alveolar bone loss in ligature-induced periodontitis in diabetic rats

OBJECTIVE

The purpose of this study was to evaluate the effects of systemically administered boric acid on alveolar bone loss, histopathological changes and oxidant/antioxidant status in ligature-induced periodontitis in diabetic rats.

MATERIALS AND METHODS

Forty-four Wistar rats were divided into six experimental groups: (1) non-ligated (NL, n = 6) group, (2) ligature only (LO, n = 6) group, (3) Streptozotocin only (STZ, n = 8) group, (4) STZ and ligature (STZ+LO, n = 8) group, (5) STZ, ligature and systemic administration of 15 mg/kg/day boric acid for 15 days (BA15, n = 8) group and (6) STZ, ligature and systemic administration of 30 mg/kg/day boric acid for 15 days (BA30, n = 8) group. Diabetes mellitus was induced by 60 mg/kg streptozotocin. Silk ligatures were placed at the gingival margin of lower first molars of the mandibular quadrant. The study duration was 15 days after diabetes induction and the animals were sacrificed at the end of this period. Changes in alveolar bone levels were clinically measured and tissues were histopathologically examined. Serum total antioxidant status (TAS), total oxidant status (TOS), calcium (Ca) and magnesium (Mg) levels and oxidative stress index (OSI) were evaluated. Primary outcome was alveolar bone loss. Seconder outcome (osteoblast number) was also measured.

RESULTS

At the end of 15 days, the alveolar bone loss was significantly higher in the STZ+LO group compared to the other groups (p < 0.05). There was no significant difference in alveolar bone loss between the STZ+LO 15 mg/kg boric acid and STZ+LO 30 mg/kg boric acid groups (p > 0.05). Systemically administered boric acid significantly decreased alveolar bone loss compared to the STZ+LO group (p < 0.05). The osteoblast number in the BA30 group was significantly higher than those of the NL, STZ and STZ+LO groups (p < 0.05). Inflammatory cell infiltration was significantly higher in the STZ+LO group the other groups (p < 0.05). Serum TAS levels were significantly higher in the NL and LO groups than the other groups (p < 0.05). The differences in TOS levels were not found to be significant among all the groups (p > 0.05). The OSI values of the BA30 group were significantly lower than the STZ+LO group (p < 0.05). Also, the differences in serum calcium and magnesium levels were insignificant among the all groups (p > 0.05).

CONCLUSION

Within the limits of this study, it can be suggested that BA, when administered systemically, may reduce alveolar bone loss in the diabetic rat model.

Evaluation of gingival crevicular fluid levels of tissue plasminogen activator, plasminogen activator inhibitor 2, matrix metalloproteinase-3 and interleukin 1-β in patients with different periodontal diseases

OBJECTIVES

The purpose of this study was to evaluate the gingival crevicular fluid levels of interleukin-1beta (IL-1β), matrix metalloproteinases-3 (MMP-3), tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor 2 (PAI-2) in patients with chronic periodontitis, aggressive periodontitis (AgP) and healthy individuals (controls).

MATERIAL AND METHODS

Systemically healthy (21 chronic periodontitis, 23 AgP and 20 controls) subjects were included in this study. Plaque index, gingival index, probing pocket depth and clinical attachment level were recorded and gingival crevicular fluid samples were collected. Assays for IL-1β, MMP-3, t-PA and PAI-2 levels in gingival crevicular fluid were carried out by an enzyme-linked immunosorbent assay. The one-sample Kolmogorov-Smirnov test, Mann-Whitney U test and Spearman correlation coefficient were used for data analyses.

RESULTS

Gingival crevicular fluid levels of t-PA and IL-1β were significantly higher in chronic periodontitis and AgP groups than in the control group (p < 0.001). MMP-3 levels in gingival crevicular fluid were detected as significantly higher in the chronic periodontitis and AgP groups compared with the control group (p < 0.05). The t-PA/PAI-2 rate of patients with chronic periodontitis and AgP were significantly higher than the control group (p < 0.05). The positive correlations were found among the PAI-2, t-PA, IL-1β and MMP-3 levels in gingival crevicular fluid. The volume of the gingival crevicular fluid correlated with all of the clinical parameters (p < 0.001). There were positive correlations between the gingival crevicular fluid levels of PAI-2 and the probing pocket depth and between gingival crevicular fluid levels of PAI-2 and the clinical attachment level (p < 0.01). Similarly, significant correlations were found between t-PA levels and probing pocket depth and between t-PA levels and clinical attachment level measurements (p < 0.001).

CONCLUSION

The present data showed that gingival crevicular fluid levels of IL-1 β, MMP-3 and t-PA increased in periodontal disease regardless of the periodontitis type and played a part in tissue destruction.

Interleukin 1 receptor 1 and interleukin 1β regulate megakaryocyte maturation, platelet activation, and transcript profile during inflammation in mice and humans

OBJECTIVE

Interleukin 1 Receptor 1 (IL1R1) and its ligand, IL1β, are upregulated in cardiovascular disease, obesity, and infection. Previously, we reported a higher level of IL1R1 transcripts in platelets from obese individuals of the Framingham Heart Study (FHS), but its functional effect in platelets has never been described. Additionally, IL1β levels are increased in atherosclerotic plaques and in bacterial infections. The aim of this work is to determine whether IL1β, through IL1R1, can activate platelets and megakaryocytes to promote atherothrombosis.

APPROACH AND RESULTS

We found that IL1β-related genes from platelets, as measured in 1819 FHS participants, were associated with increased body mass index, and a direct relationship was shown in wild-type mice fed a high-fat diet. Mechanistically, IL1β activated nuclear factor-κB and mitogen-activated protein kinase signaling pathways in megakaryocytes. IL1β, through IL1R1, increased ploidy of megakaryocytes to 64+ N by 2-fold over control. IL1β increased agonist-induced platelet aggregation by 1.2-fold with thrombin and 4.2-fold with collagen. IL1β increased adhesion to both collagen and fibrinogen, and heterotypic aggregation by 1.9-fold over resting. High fat diet-enhanced platelet adhesion was absent in IL1R1(-/-) mice. Wild-type mice infected with Porphyromonas gingivalis had circulating heterotypic aggregates (1.5-fold more than control at 24 hours and 6.2-fold more at 6 weeks) that were absent in infected IL1R1(-/-) and IL1β(-/-) mice.

CONCLUSIONS

In summary, IL1R1- and IL1β-related transcripts are elevated in the setting of obesity. IL1R1/IL1β augment both megakaryocyte and platelet functions, thereby promoting a prothrombotic environment during infection and obesity; potentially contributing to the development of atherothrombotic disease.

Effect of low-dose doxycycline on serum oxidative status, gingival antioxidant levels, and alveolar bone loss in experimental periodontitis in rats

BACKGROUND

Subantibiotic doses of doxycycline (low-dose doxycycline [LDD]) have been widely used in periodontal treatment for enzymatic inhibition and related anti-inflammatory properties. The aim of the present study is to verify the possible effects of LDD on oxidative stress in relation to periodontal attachment loss associated with ligature-induced experimental periodontal disease in rats.

METHODS

Thirty female Wistar albino rats were divided into three study groups as follows: 1) control (C) rats; 2) rats with experimental periodontitis (PED); and 3) rats with PED that were treated with doxycycline (PED + LDD). PED was induced by placing ligatures around the cervix of the maxillary second molars for 21 days. The PED + LDD group was treated orally with doxycycline (6 mg/kg) for 21 days after the ligature was placed. After 21 days, the rats were euthanized, and samples of the right maxilla were defleshed and used for histologic and morphometric analyses. The gingival tissue of the left maxilla was used for the analysis of lipid peroxidation (malondialdehyde [MDA]) and antioxidant enzymes (catalase, glutathione peroxidase, and superoxide dismutase). Levels of serum total antioxidant status (TAS)/total oxidant status (TOS) and oxidative stress index (OSI) were also analyzed.

RESULTS

Alveolar bone loss was significantly higher in the PED group compared with the PED + LDD and C groups (P <0.05). Doxycycline exhibited the most prominent inhibition on gingival tissue levels of MDA and antioxidant enzymes (P <0.05). Doxycycline also significantly reduced TOS and OSI levels (P <0.05) but increased the TAS level.

CONCLUSION

Doxycycline helps to prevent periodontal tissue breakdown by inhibiting local and systemic oxidative stress.