Comparative evaluation of sclerostin levels in gingival crevicular fluid of periodontal health and disease before and after nonsurgical periodontal therapy

Ankita Mathur; D Gopalakrishnan; Sharath Shetty; Vini Mehta; Shreya Bagwe

doi:10.4103/jhnps.jhnps_48_22

ORIGINAL ARTICLE

Year : 2022 | Volume : 10 | Issue : 2 | Page : 157-161

Comparative evaluation of sclerostin levels in gingival crevicular fluid of periodontal health and disease before and after nonsurgical periodontal therapy

Ankita Mathur¹, D Gopalakrishnan², Sharath Shetty², Vini Mehta³, Shreya Bagwe⁴
¹ Co-Founder, STAT SENSE, Srushti 10, Sector 1 D, Amba Township Pvt. Ltd., Trimandir, Adalaj, Gujarat, India
² Department of Periodontology, Dr. D.Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, Maharashtra, India
³ Department of Public Health Dentistry, Dr. D.Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, Maharashtra, India
⁴ Private Practitioner, Navi Mumbai, Maharashtra, India

Date of Submission	28-Jul-2022
Date of Decision	03-Aug-2022
Date of Acceptance	10-Aug-2022
Date of Web Publication	15-Dec-2022

Correspondence Address:
Vini Mehta
Department of Public Health Dentistry, Dr. D.Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune - 411 018, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jhnps.jhnps_48_22

Abstract

Aim: The purpose of this study was to measure the concentration of sclerostin in the gingival crevicular fluid (GCF) before and after 1, 3, and 6 weeks of nonsurgical periodontal therapy (NSPT) in subjects with and without chronic periodontitis. Materials and Methods: An interventional study was conducted among 35 subjects of age groups 30–50 years. Subjects were divided into three groups: Group I (10 healthy individuals), Group II (10 gingivitis), and Group III (15 chronic periodontitis only). Clinical parameters assessed were gingival index (GI), plaque index (PI), probing pocket depth (PPD), and clinical attachment level (CAL). The GCF samples were collected from all the groups at baseline and in Group III at baseline and 1, 3, and 6 weeks after NSPT using micropipettes. Results: Table 1 shows age and gender details. Although the mean sclerostin concentration in GCF (ng/ml) was highest in Group III at baseline (5.41 ± 0.68) and lowest in Group 1 (4.98 ± 0.46), there was no statistically significant difference (P < 0.05) when intergroup comparison was done [Tables 2 and 3]. PPD and CAL measured for Group III were 6.93 + 1.2 and 7.67 + 1.2, respectively. PI (2.52 + 0.25) and GI (2.52 + 0.17) were measured highest in Group III [Table 4]. Conclusion: There was a substantial decrease in the concentration of sclerostin in the GCF of chronic periodontitis patients after 1, 3, and 6 weeks after NSPT. This proves sclerostin to be a responsive measure of inflammation in periodontal destruction.

Keywords: Gingival crevicular fluid, periodontitis, sclerostin

How to cite this article:
Mathur A, Gopalakrishnan D, Shetty S, Mehta V, Bagwe S. Comparative evaluation of sclerostin levels in gingival crevicular fluid of periodontal health and disease before and after nonsurgical periodontal therapy. J Head Neck Physicians Surg 2022;10:157-61

How to cite this URL:
Mathur A, Gopalakrishnan D, Shetty S, Mehta V, Bagwe S. Comparative evaluation of sclerostin levels in gingival crevicular fluid of periodontal health and disease before and after nonsurgical periodontal therapy. J Head Neck Physicians Surg [serial online] 2022 [cited 2023 Jun 4];10:157-61. Available from: https://www.jhnps.org/text.asp?2022/10/2/157/363927

Introduction

Periodontal disease is characterized by a chronic inflammatory disorder of the periodontal supporting tissues of teeth involving destructive and nondestructive diseases.^[1],[2] Bleeding on probing, probing pocket depth (PPD), clinical attachment loss, tooth mobility, and furcation involvement are indicators of periodontal disease.^[3] However, these parameters do not throw light on the patient's disease activity and risk for disease progression.^[4] Hence, the clinician needs a diagnostic tool that would aid in his identification of individuals with active disease and/or risk for disease progression.^[1]

SOST is a gene located on chromosome 17q12-21, which provides instructions for making the protein sclerostin. Sclerostin is a glycoprotein of 190 amino acids, a potent inhibitor of constructive metabolism of bone-forming osteoblast cells. Osteocytes are sensitive to mechanical stimulation and aid in osteogenesis by reducing sclerostin secretion. Thus, bone response to mechanical loading largely depends on sclerostin.^[3] It has emerged as a negative regulator of osteoblast activity by restraining Wingless-related integrated site (Wnt) signaling, which is crucial in modulating the transcription of genes fundamental for maintenance of tissue homeostasis, including bone and cartilage.^[4]

The main function of sclerostin is to inhibit the anabolic output of bone-forming osteoblast cells. However, an unconfirmed report has shown that sclerostin might also stimulate osteoclast formation, which aids in resorption of bone and activity by viable osteocytes. This has added a new perspective to our understanding of the function of sclerostin as a procatabolic modulator as well as an antianabolic, inhibitor of bone formation. Sclerostin is involved in bone modeling and remodeling as well.^[4] Under physiological conditions, osteocytes, which are bone mechanosensors, capable of driving loading information to cells placed on the bone surface, almost exclusively synthesize sclerostin. In the process of unloading, sclerostin levels rise resulting in decrease of bone formation through Wnt signaling, while the reverse process takes place in the bones subjected to loading which show reduction of sclerostin.^[3]

In view of the functions of sclerostin, it may be reasonable to speculate that it plays a predominant role in the protection of periodontal tissue. We may theorize that an analysis of crevicular sclerostin concentrations may be used to distinguish subjects with active disease and/or at risk of disease progression. Therefore, the present study aims at measuring the concentration of sclerostin in the gingival crevicular fluid (GCF) before and after 1, 3, and 6 weeks of nonsurgical periodontal therapy (NSPT) in subjects with and without chronic periodontitis.

Materials and Methods

A total of 35 subjects aged 30–50 years of either sex were selected from the outpatient department of periodontology in a period of 1 year. The study was approved by the institutional ethics committee. The procedure was explained and written informed consent was obtained. Subjects with a presence of minimum number of 14 natural teeth, systemically healthy patients, and subjects with a diagnosis of chronic periodontitis based on clinical parameters such as probing depth, clinical attachment level, gingival index (GI), plaque index (PI), and normal serum calcium and phosphate levels were included in the study. Patients on bisphosphonates, alendronate therapy, Vitamin D, calcium supplements, steroids, contraceptives, and anti-inflammatory drugs; postmenopausal female subjects; aggressive periodontitis patients; patients who received antibiotic therapy within the past 6 months; patients who have undergone periodontal treatment in the past 6 months; patients who have completed orthodontic treatment 6 months back; patients who were using tobacco in any form; or pregnant and lactating mothers were excluded.

Subjects were stratified into three groups based on PPD, clinical attachment level (CAL), PI,^[5] GI,^[6] and radiographic evidence of bone loss on osteoprotegerin (OPG) to differentiate chronic periodontitis patients from gingivitis and periodontally healthy patients.

Group I: 10 periodontally healthy subjects (PI <1, GI <1, PPD ≤3 mm, clinical attachment level (CAL) =0 mm)
Group II: 10 gingivitis patients (GI ≥1, GI ≥1, PPD ≤3 mm, CAL = 0 mm)
Group III: 15 chronic periodontitis patients at baseline (GI ≥1, PPD ≥5 mm, CAL ≥3 mm and evidence of Radiographic bone loss on OPG). Group III patients were reevaluated at 1, 3, and 6 weeks post-NSPT. A total of 80 samples from 35 patients were collected.

Clinical procedure

In Groups I, II, and III, all the clinical parameters were recorded. On the subsequent day, after drying the area with a blast of air, supragingival plaque was removed with curette (Hu-Friedy-USA) without touching the marginal gingiva and the area was isolated with cotton rolls to avoid saliva contamination. GCF was collected using a white color-coded 1–5 μL calibrated volumetric microcapillary pipette (Sigma-Aldrich). From each test site, a standardized volume of 1 μL was collected using the calibration on the micropipette and by placing the tip of the pipette extracrevicularly (unstimulated). A maximum of 10 min was given for each sample collection, and the sites that did not express any GCF within the allotted time were excluded. The micropipettes contaminated with blood and saliva were also excluded. The GCF collected was immediately transferred to a plastic vial and stored at -70°C until the assay. In Group III, thorough full-mouth supra- and subgingival scaling and root planing was performed with the help of ultrasonic scalers and curettes and was completed within 24 h. Patients were instructed to maintain oral hygiene by brushing teeth twice daily and rinsing after every meal. Chlorhexidine 2% mouthwash was given for 2 weeks. Patients were recalled at 1, 3, and 6 weeks for follow-ups. Full-mouth periodontal reassessment was carried out after which GCF samples were collected again from the same site and stored at -70°C until assay. Estimation of sclerostin levels of GCF was carried out with the help of enzyme-linked immunosorbent assay.

Statistical analysis

The data were analyzed with Statistical Package for the Social Sciences (SPSS) for Windows 25.0 (SPSS, Inc., Chicago, Illinois, USA). Confidence intervals were set at 95% and values of P < 0.05 were interpreted as statistically significant. Descriptive statistics was applied for demographic details and clinical parameters. Repeated measures ANOVA was used to check the significance of difference in the mean sclerostin concentration in GCF (ng/ml) at 1, 3, and 6 weeks for periodontitis group.

Results

[Table 1] shows age and gender details. Although the mean sclerostin concentration in GCF (ng/ml) was highest in Group III at baseline (5.41 ± 0.68) and lowest in Group 1 (4.98 ± 0.46), there was no statistically significant difference (P < 0.05) when intergroup comparison was done [Table 2] and [Table 3]. PPD and CAL measured for Group III were 6.93 ± 1.2 and 7.67 ± 1.2, respectively. PI (2.52 ± 0.25) and GI (2.52 ± 0.17) were measured highest in Group III [Table 4].

Table 1: Demographic details

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Table 2: Comparison of mean values of sclerostin at baseline concentration in gingival crevicular fluid for all groups

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Table 3: Intergroup comparison of sclerostin concentration in gingival crevicular fluid

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Table 4: Comparison of mean values for clinical parameters in all groups

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Discussion

Chronic periodontitis is one of the most prevalent low-grade, bacterially induced chronic inflammatory diseases affecting 20%–50% of the adult population worldwide. The low-grade inflammation associated with chronic periodontitis is characterized by increased levels of circulating proinflammatory cytokines and bone resorption markers.^[7],[8]

The familiar basic advantage of biochemical markers, compared with bone mineral densitometry and static histomorphometric analysis of bone biopsy, is that using them, we get the information about the status of bone remodeling. In addition, biochemical markers are noninvasive with regard to dynamic histomorphometric analysis of bone biopsy.^[9],[10] GCF constituents reflect local cellular response in gingival tissue, and also collection of GCF is a minimally invasive procedure rather than gingival biopsies. Moreover, GCF is suitable for evaluating both periodontal disease status and the outcome of therapy.^[11] Taken together, in the present study, the levels of sclerostin were analyzed in GCF samples of healthy and periodontitis subjects before and after NSPT at 1, 3, and 6 weeks.

The evaluation of PI and GI scores are important indicators of increasing risk of periodontal diseases. The association of PI and GI and levels of sclerostin has been investigated in previous studies. Balli et al.^[12] found strong positive correlations between GI scores and CALs with respect to sclerostin. The study showed an increase in PPD, CAL, and SOST values when associated with increased severity of periodontal disease.

The mean PI score in Group III at baseline was 2.52 ± 0.25 and for GI it was 2.52 ± 0.17, which were rated as poor in PI index^[5] (Silness and Loe, 1964) and fall in severe gingivitis category in GI index^[6] (Loe and Silness, 1963). This is similar to the study conducted by Balli et al.^[12] The comparison of mean SOST values between Group I and Group II and Group III at baseline, 1, 3, and 6 weeks did not show a significant difference between these groups. The results of our study are similar to the study conducted by Balli et al. (2015).^[12] The patients in Group III were given NSPT and strict oral hygiene instructions. The mean SOST values in Group III after treatment were reduced significantly from pretreatment score. This substantial decrease in SOST values in our study as a result of NSPT is similar to the study conducted by Balli et al.^[12]

Balli et al. investigated the changes in the levels and relative ratios of sclerostin, osteoprotegerin, and receptor activator of nuclear factor-κB ligand (RANKL) in the GCF of periodontitis patients after nonsurgical periodontal treatment and found that the GCF sclerostin level may be more reliable than the RANKL/osteoprotegerin ratio as a diagnostic and prognostic marker of periodontal disease and treatment outcome.^[12]

Bone metabolism is controlled by a delicate balance between osteoblasts and osteoclasts. Sclerostin is a biomarker that negatively regulates bone formation by antagonizing osteoblastogenesis and the Wingless-related integration site signaling pathway. Suppression of sclerostin leads to increased bone mineral density, bone volume, bone formation, and bone strength in mice.^[13],[14] The administration of antisclerostin antibody to ovariectomized rats and nonovariectomized monkeys has been associated with increased bone mass and strength on trabecular, periosteal, endocortical, and intracortical surfaces.^[15],[16] Moreover, humanized monoclonal antibody has an anabolic effect on bone metabolism, with marked increases in bone mineral density and bone formation and a decrease in bone resorption.^{[17],[18],[19]} There is evidence that ligature-induced alveolar bone loss is associated with increased expression of RANKL (enhanced osteoclast formation) and sclerostin (suppressed osteoid formation).^[18] In the present study, sclerostin levels in GCF were higher in patients with chronic periodontitis than in healthy individuals. Only one clinical study has explored the involvement of sclerostin in periodontitis. In a study done by Napimoga et al. in 2014, sclerostin was upregulated in the gingival tissue samples of chronic periodontitis patients; this is similar to our findings in our Group III patients. It was also reported that sclerostin levels were positively correlated with PPD and CAL.^[20]

The increase in SOST levels in the chronic periodontitis group and subsequent reduction after NSPT showed that SOST levels change according to the level of inflammatory burden present in different stages of disease and treatment. Thus, the findings suggest SOST to be a potential marker of inflammation in periodontal disease having a prognostic potential for periodontal treatment outcomes. Further longitudinal studies evaluating the levels of SOST in GCF, saliva along with serum, and after surgical periodontal therapy should be carried out to confirm the role of SOST as an inflammatory marker in periodontal disease.

Conclusion

There are a substantial increase in the concentration of sclerostin in the GCF of periodontally healthy subjects and gingivitis and chronic periodontitis patients and a substantial decrease in the concentration of sclerostin in the GCF of chronic periodontitis patients after 1, 3, and 6 weeks after NSPT was observed. This proves sclerostin to be a responsive measure of inflammation in periodontal destruction. It also shows that inflammatory stress increases as the periodontal disease advances from healthy to a diseased state. To conclude, within the limitations of the current study, it can be postulated that sclerostin can be regarded as a marker of inflammation of chronic periodontitis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Disclosure

This material has never been published and is not currently under evaluation in any other peer-reviewed publication.

Ethical approval

The permission was taken from the institutional ethics committee prior to starting the project. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.

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