Type I collagen carboxyterminal telopeptide in human gingival crevicular fluid in different clinical conditions and after periodontal treatment

Evaluation of deoxypyridinoline levels in gingival crevicular fluid and serum as alveolar bone loss biomarker in patients with periodontitis

Background:

Several components of gingival crevicular fluid (GCF) reflect the course and predictability of periodontal disease and provide a pointer toward disease status. Potential biomarkers deoxypyridinoline (DPD), a metallophosphoesterase would correctly determine the presence of osteoclast-mediated bone turnover activity and seems to hold great promise as a predictive marker to determine bone destruction and active phases in the disease progression.

Aim:

The aim of the current study is proposed to investigate the biologic plausibility for the levels of DPD as biomarker in chronic periodontitis patients.

Materials and Methods:

The present cross-sectional study comprised 15 periodontally healthy and 15 chronic periodontitis patients who were age and genders matched, recruited from the outpatient department of Periodontics. GCF and blood samples for DPD estimation were collected from all the patients and analyzed using enzyme-linked immunosorbent assay kit. The clinical parameters such as clinical attachment loss (CAL), probing pocket depth (PPD), modified gingival index, bleeding index , and plaque index were recorded.

Results:

GCF DPD levels were significantly higher in chronic periodontitis patients when compared to periodontally healthy group. There were no significant correlations found among GCF and serum DPD levels with increasing age, gender, disease severity, and increase in PPD and CAL in both the groups.

Conclusion:

Within the limitations of this study, increased GCF DPD levels in chronic periodontitis can gauge ongoing periodontal destruction.

Plasma levels of N-telopeptide of Type I collagen in periodontal health, disease and after treatment

Background:

To determine plasma concentrations of bone resorption marker cross-linked N-terminal telopeptide (NTx) of Type I collagen in periodontal health, disease and after nonsurgical periodontal therapy in chronic periodontitis group. In addition, to know the association between plasma NTx levels and the different clinical parameters.

Materials and Methods:

Thirty subjects were divided on the basis of their periodontal status and were categorized as Group I: Healthy, Group II: Gingivitis, and Group III: Chronic periodontitis. Group III subjects were treated with scaling and root planing, 6-8 weeks later blood samples were analyzed, and they constituted Group IV. NTx levels in plasma were analyzed by competitive - enzyme-linked immunosorbent assay. All data were analyzed using statistical software (SPSS) (α = 0.05).

Results:

All the samples tested positive for the presence of NTx. The mean NTx concentration was highest in Group III (18.77 nanomole Bone Collagen Equivalent [nm BCE]) and the lowest in Group IV (16.02 nm BCE). The values of Group I and Group II fell between the highest and the lowest values (16.23 nm BCE and 16.70 nm BCE, respectively). The difference in mean NTx levels in Group III and Group IV were statistically significant. NTx levels in all the groups positively correlated with the clinical parameters. All data were analyzed using statistical software (SPSS) (α = 0.05).

Conclusion:

Within the limits of this study, it may be suggested that plasma NTx levels may provide distinguishing data between periodontally healthy diseased sites and after nonsurgical therapy of diseased sites.

Effect of gingival application of melatonin on alkaline and acid phosphatase, osteopontin and osteocalcin in patients with diabetes and periodontal disease

Objectives: To assess the effect of topical application of melatonin to the gingiva on salivary fluid concentrations of acid phosphatase, alkaline phosphatase, osteopontin, and osteocalcin. Study Design: Cross-sectional study of 30 patients with diabetes and periodontal disease and 30 healthy subjects. Diabetic patients were treated with topical application of melatonin (1% orabase cream formula) once daily for 20 days and controls with a placebo formulation. Results: Before treatment with melatonin, diabetic patients showed significantly higher mean salivary levels of alkaline and acid phosphatase, osteopontin and osteocalcin than healthy subjects (P < 0.01). After treatment with melatonin, there was a statistically significant decrease of the gingival index (15.84± 10.3 vs 5.6 ± 5.1) and pocket depth (28.3 ± 19.5 vs 11.9 ± 9.0) (P < 0.001). Also, use of melatonin was associated with a significant reduction of the four biomarkers. Changes of salivary acid phosphatase and osteopontin correlated significantly with changes in the gingival index, whereas changes of alkaline phosphatase and osteopontin correlated significantly with changes in the pocket depth. Conclusions: Treatment with topical melatonin was associated with an improvement in the gingival index and pocket depth, a reduction in salivary concentrations of acid phosphatase, alkaline phosphatase, osteopontin and osteocalcin.

Key words:Melatonin, diabetes mellitus, alkaline phosphatase, acid phosphatase, osteopontin, osteocalcin.

Saliva: A diagnostic biomarker of periodontal diseases

Early detection of disease plays a crucial role in successful therapy. Early diagnosis and management reduces the severity and possible complications of the disease process. To overcome this challenge, medical researchers are devoted to finding molecular disease biomarkers that reveal a hidden lethal threat before the disease becomes complicated. Saliva, an important physiologic fluid, containing a highly complex mixture of substances, is rapidly gaining popularity as a diagnostic tool. Periodontal disease is a chronic disease of the oral cavity comprising a group of inflammatory conditions affecting the supporting structures of the dentition. In the field of periodontology, traditional clinical criteria are often insufficient for determining sites of active disease, for monitoring the response to therapy, or for measuring the degree of susceptibility to future disease progression. Saliva, as a mirror of oral and systemic health, is a valuable source for clinically relevant information because it contains biomarkers specific for the unique physiologic aspects of periodontal diseases. This review highlights the various potentials of saliva as a diagnostic biomarker for periodontal diseases.

Bone remodeling biomarkers of periodontal disease in saliva

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha), C-telopeptide pyridinoline cross-links of type I collagen (ICTP), and receptor activator of nuclear factor-kappa B ligand (RANKL) have been associated with bone remodeling and periodontal tissue destruction. This study evaluated the level of these biomarkers in saliva with respect to periodontal disease status.

METHODS

Levels of TNF-alpha in unstimulated whole saliva of 74 adults (35 subjects with moderate to severe periodontal disease and 39 healthy controls) and salivary levels of RANKL and ICTP of a subset of 21 subjects and 21 matched controls were examined using enzyme immunosorbent assays in a case-control clinical study.

RESULTS

Salivary levels of TNF-alpha were detected in all subjects, whereas levels of ICTP and RANKL were detected in only a minority of subjects. Mean salivary levels of TNF-alpha were significantly higher in individuals with periodontal disease (mean: 4.33 pg/ml) than in controls (mean: 2.03 pg/ml; P = 0.02), with a maximum level (27.96 pg/ml) observed in periodontitis. Subjects with salivary TNF-alpha levels above a threshold of 5.75 pg/ml (i.e., two standard deviations above the mean of the controls) had significantly more sites with bleeding on probing, probing depths >/=4 mm, and attachment loss > or =2 mm (P < or =0.01).

CONCLUSION

Salivary levels of TNF-alpha were elevated in patients who had clinical indicators of periodontitis, suggesting that this biomarker may serve in a panel of salivary biomarkers that could facilitate the screening, diagnosis, and management of periodontal disease.

Candidate salivary biomarkers associated with alveolar bone loss: cross-sectional and in vitro studies

This cross-sectional study evaluated the association between radiographic evidence of alveolar bone loss and the concentration of host-derived bone resorptive factors (interleukin-1 beta, tumor necrosis factor-alpha, interleukin-6, prostaglandin-E2), and markers of bone turnover [pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), osteocalcin, osteonectin] in stimulated human whole saliva collected from 110 untreated dental patients. Alveolar bone loss scores for each patient were derived from radiographic examination. Variables positively associated with increased bone loss score were: age, current smoking, use of bisphosphonate drugs, and salivary interleukin-1beta levels above the median. Salivary osteonectin levels above the median were associated with a decreased bone loss score. Additional in vitro studies were carried out to determine the fate of interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha added to whole and parotid saliva. All cytokines added to saliva were detected in significantly lower concentrations than when added to buffer alone. Protease inhibitors added to saliva did not prevent the reduction in detection of biomarkers. Variation in time of incubation, repeated cycles of freezing and thawing, or exposure to dimethylsulfoxide did not appreciably affect the measurement of cytokines in saliva. These results suggest that detection of biomarkers by conventional immunoassays may underestimate the actual quantity of molecules in saliva.

Oral fluid-based biomarkers of alveolar bone loss in periodontitis

Periodontal disease is a bacteria-induced chronic inflammatory disease affecting the soft and hard supporting structures encompassing the teeth. When left untreated, the ultimate outcome is alveolar bone loss and exfoliation of the involved teeth. Traditional periodontal diagnostic methods include assessment of clinical parameters and radiographs. Though efficient, these conventional techniques are inherently limited in that only a historical perspective, not current appraisal, of disease status can be determined. Advances in the use of oral fluids as possible biological samples for objective measures of current disease state, treatment monitoring, and prognostic indicators have boosted saliva and other oral-based fluids to the forefront of technology. Oral fluids contain locally and systemically derived mediators of periodontal disease, including microbial, host-response, and bone-specific resorptive markers. Although most biomarkers in oral fluids represent inflammatory mediators, several specific collagen degradation and bone turnover-related molecules have emerged as possible measures of periodontal disease activity. Pyridinoline cross-linked carboxyterminal telopeptide (ICTP), for example, has been highly correlated with clinical features of the disease and decreases in response to intervention therapies, and has been shown to possess predictive properties for possible future disease activity. One foreseeable benefit of an oral fluid-based periodontal diagnostic would be identification of highly susceptible individuals prior to overt disease. Timely detection and diagnosis of disease may significantly affect the clinical management of periodontal patients by offering earlier, less invasive, and more cost-effective treatment therapies.

Gingival crevicular fluid osteopontin levels in periodontal health and disease

BACKGROUND

Osteopontin (OPN), a glycosylated phosphoprotein, is a bone matrix component produced by osteoblasts, osteoclasts, and macrophages as a multifunctional cytokine. OPN anchors osteoclasts to the bone surface, and its absence leads to impaired bone resorption. The aim of the present study was to assess the relation between clinical parameters and concentrations of OPN within gingival crevicular fluid (GCF) from inflamed gingiva and periodontitis sites and, subsequently, after the treatment of periodontitis sites.

METHODS

A total of 45 subjects were divided into the following three groups based on modified gingival index (MGI) and Ramfjord periodontal disease index (PDI) scores: healthy (group I), gingivitis (group II), and chronic periodontitis (group III). A fourth group consisted of 15 subjects from group III, 6 to 8 weeks after treatment (i.e., scaling and root planing [SRP]). GCF samples collected from each patient were quantified for OPN using the enzymatic immunometric assay. Further, the correlation between OPN levels in situ with clinical parameters was analyzed in all groups and before and after treatment in periodontitis patients.

RESULTS

The highest mean OPN concentration in GCF (14.347 microg/ml) was observed in group III, and the lowest mean OPN concentration in GCF (2.522 microg/ml) was observed in group I. Its levels in group III decreased to 8.419 microg/ml after treatment (group IV). Further, GCF OPN levels in all the groups showed a statistically significant positive correlation with clinical attachment loss (P <0.05).

CONCLUSIONS

OPN levels increase in GCF from healthy to periodontitis states, and periodontal treatment results in the reduction of OPN levels. The data indicate that OPN may play a key role in, and could be considered a biomarker of, periodontal disease progression.

Effect of rhPDGF-BB delivery on mediators of periodontal wound repair

Growth factors such as platelet-derived growth factor (PDGF) exert potent effects on wound healing including the regeneration of tooth-supporting structures. This investigation examined the effect of the local delivery of PDGF-BB when combined with reconstructive periodontal surgery on local wound fluid (WF) levels of PDGF-AB, vascular endothelial growth factor (VEGF), and bone collagen telopeptide (ICTP) in humans with advanced periodontitis. Sixteen patients exhibiting localized periodontal osseous defects were randomized to one of three groups (beta-TCP carrier alone, beta-TCP + 0.3 mg/mL of recombinant human PDGF-BB [rhPDGF-BB], or beta-TCP + 1.0 mg/mL of rhPDGF-BB) and monitored for 6 months. WF was harvested and analyzed for PDGF-AB, VEGF, and ICTP WF levels. Teeth contralateral to the target lesions served as controls. Increased levels of VEGF in the WF was observed for all surgical treatment groups with the 1.0 mg/mL rhPDGF-BB group showing the most pronounced difference at 3 weeks in the AUC analysis versus control (p < 0.0001). PDGF-AB WF levels were increased for the carrier alone group compared to both rhPDGFBB groups. Low-dose rhPDGF-BB application elicited increases in ICTP at days 3-5 in the wound healing process, suggesting a promotion of bone turnover at early stages of the repair process (p < 0.02). These results demonstrate contrasting inducible expression patterns of PDGF-AB, VEGF, and ICTP during periodontal wound healing in humans.

Effect of rhPDGF-BB on bone turnover during periodontal repair

PURPOSE

Growth factors such as platelet-derived growth factor (PDGF) exert potent effects on wound healing including the regeneration of periodontia. Pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) is a well-known biomarker of bone turnover, and as such is a potential indicator of osseous metabolic activity. The objective of this study was to evaluate the release of the ICTP into the periodontal wound fluid (WF) following periodontal reconstructive surgery using local delivery of highly purified recombinant human PDGF (rhPDGF)-BB.

METHODS

Forty-seven human subjects at five treatment centres possessing chronic severe periodontal disease were monitored longitudinally for 24 weeks following PDGF regenerative surgical treatment. Severe periodontal osseous defects were divided into one of three groups and treated at the time of surgery with either: beta-tricalcium phosphate (TCP) osteoconductive scaffold alone (active control), beta-TCP+0.3 mg/ml of rhPDGF-BB, or beta-TCP+1.0 mg/ml of rhPDGF-BB. WF was harvested and analysed for local ICTP levels by radioimmunoassay. Statistical analysis was performed using analysis of variance and an area under the curve analysis (AUC).

RESULTS

The 0.3 and 1.0 mg/ml PDGF-BB treatment groups demonstrated increases in the amount of ICTP released locally for up to 6 weeks. There were statistically significant differences at the week 6 time point between beta-TCP carrier alone group versus 0.3 mg/ml PDGF-BB group (p<0.05) and between beta-TCP alone versus the 1.0 mg/ml PDGF-BB-treated lesions (p<0.03). The AUC analysis revealed no statistical differences amongst groups.

CONCLUSION

This study corroborates the release of ICTP as a measure of active bone turnover following local delivery of PDGF-BB to periodontal osseous defects. The amount of ICTP released from the WF revealed an early increase for all treatment groups. Data from this study suggests that when PDGF-BB is delivered to promote periodontal tissue engineering of tooth-supporting osseous defects, there is a direct effect on ICTP released from the wound.

Relationship between gelatinases and bone turnover in the healing bone defect

PURPOSE

The aim of this pilot study was to determine the relationship between gelatinase (MMP-9 and MMP-2) markers of soft tissue inflammation/turnover at the bone/soft tissue interface and bone turnover (osteocalcin [OC], pyridinoline cross-linked carboxyl-terminal telopeptide of type 1 collagen [ICTP], and bone fill) during healing of an alveolar bone defect.

MATERIALS AND METHODS

Ten subjects undergoing oral surgery had a 5 x 5-mm trephine defect created on an edentulous ridge and were sampled at the bone/soft tissue interface at baseline (prior to flap reflection), 2 weeks and 12 weeks postsurgery, using a novel bone wash device. Recovered irrigants were analyzed for MMP-9 and MMP-2 by gelatin zymography, OC and ICTP with radioimmunoassays, and albumin (ALB; to normalize markers for blood content) with a sandwich enzyme-linked immunosorbent assay. Bone fill at 12 weeks was analyzed by radiographic absorptiometry.

RESULTS

All markers of enzymatic activity and bone turnover varied significantly across time (P < or = .03), with bone turnover markers OC and ICTP decreasing between baseline and 2 weeks, and MMP-9 and MMP-2 increased. Measures generally returned to near baseline levels after 12 weeks. MMP-9 versus MMP-2 (r = 0.97, P < .0001) and OC versus ICTP (r = 0.38, P = .048) were correlated with each other, while MMP-9 and MMP-2 were negatively correlated with ICTP (r = -0.48, P = .011 and r = -0.62, P = .006, respectively). MMP-9 was negatively correlated with subsequent bone fill (r = -0.63, P = .07).

CONCLUSIONS

Bone wash sampling showed that gelatinase activity at 2 weeks following creation of an alveolar defect appeared to decrease bone turnover and eventual bone fill, suggesting benefits for anti-MMP therapy during wound healing.

Diagnostic biomarkers for oral and periodontal diseases

This article provides an overview of periodontal disease diagnosis that uses clinical parameters and biomarkers of the disease process.This article discusses the use of biomarkers of disease that can be identified at the tissue, cellular, and molecular levels and that are measurable in oral fluids such as saliva and gingival crevicular fluid. Biomarkers identified from these biologic fluids include microbial, host response, and connective tissue-related molecules that can target specific pathways of local alveolar bone resorption. Future prospects for oral fluid-based diagnostics that use micro-array and microfluidic technologies are presented.

Local biochemical markers of bone turnover: relationship to subsequent density of healing alveolar bone defects

OBJECTIVES

This pilot study was designed to test whether biochemical markers of bone turnover in washes of periosteal or trabecular alveolar bone surfaces could be correlated with increases in bone density of an adjacent healing implant socket.

METHODS

Ten subjects had a canula inserted into the alveolar crest and sterile phosphate-buffered saline was washed over the periosteal and trabecular surfaces and collected. Surgical flaps were reflected, 5 mm diameter bone cores were removed from the bone wash site, and standardized radiographs were taken. The sites were allowed to heal for 12 weeks, and radiographs were repeated. Bone washes of the healing sites were also collected after 2 and 12 weeks. Washes were analysed for bone turnover markers osteocalcin (OC; radioimmunoassay) and C-terminal telopeptide of Type 1 collagen (ICTP; enzyme-linked immunosorbent assay (ELISA)), and blood component albumin (ALB; ELISA). Changes in bone density during healing were determined by radiographic absorptiometry.

RESULTS

OC/ALB and ICTP/ALB ratios were higher for trabecular than periosteal washes at baseline (p<or=0.01). Trabecular OC/ALB and ICTP/ALB were inversely correlated with increasing bone density of the healing bone core socket (r=-0.72, p=0.03; Pearson's correlation coefficient).

CONCLUSIONS

Biochemical markers of bone turnover in bone washes of specific alveolar bone sites may prove helpful in predicting how the bone density will increase around healing dental implants.

Extracellular matrix metabolites as potential biomarkers of disease activity in wound fluid: lessons learned from other inflammatory diseases?

The new era of pharmacogenetics has identified a potential for individuals to receive customized treatments for a variety of disease states. For such individualized treatments to fulfil their potential, it will be essential for clinicians to be able to monitor disease activity, ideally in a rapid, noninvasive fashion. The accessibility of the skin offers much potential to develop noninvasive tests of metabolic and disease activity for clinical use. Impaired human wound healing in the skin is a chronic inflammatory disorder in which the development of such tests has considerable potential, aiding clinical decision making and monitoring responses to treatment. This review article discusses how studies in other human diseases have highlighted potential biochemical markers (biomarkers) of disease activity in secreted biofluids, as aids to determining disease and metabolic activity within tissues. Using, as examples, lessons learned in the study of disease activity and prognosis of other chronic inflammatory conditions, such as osteoarthritis and periodontal disease, this review highlights the potential of dermal extracellular matrix (ECM) components (collagens, proteoglycans, hyaluronan and glycoproteins) for such uses. The limitations of currently utilized techniques and the concept that analysis of ECM components in wound fluid may represent useful biomarkers of disease activity are also discussed.

Inter-relationships between rheumatoid arthritis and periodontal disease. A review

This review considers the considerable similarities between periodontal disease and rheumatoid arthritis (RA). While the etiology of these two diseases may differ, the underlying pathogenic mechanisms are remarkably similar and it is possible that individuals manifesting both periodontitis and RA may suffer from a unifying underlying systemic dysregulation of the inflammatory response. In light of these findings, the implications for the use of disease-modifying medications in the management of these two chronic inflammatory conditions is apparent. Further longitudinal studies and medication-based intervention studies are required to determine just how closely these two conditions are allied.

Position Paper: Diagnosis of Periodontal Diseases

At the present time, the diagnosis and classification of periodontal diseases are almost entirely based on traditional clinical assessments. Supplemental quantitative and qualitative assessments of the gingival crevicular fluid and subgingival microflora can potentially provide useful information about the patient's periodontal disease. In certain situations, these supplemental risk-assessment tests may be particularly valuable in establishing the endpoint of therapy prior to placing patients on a periodontal maintenance program. Although the clinical utility of none of these tests has been validated, their further development is warranted. A genetic test for susceptibility to periodontitis has become commercially available. How best to use this and future host-based tests in clinical practice remains to be determined. Probing depth and clinical attachment loss measurements obtained with periodontal probes are practical and valid methods for assessing periodontal status. Computer-linked, controlled-force electronic periodontal probes are commercially available and are currently in use by some practitioners. Many of the logistical problems associated with subtraction radiography are being overcome and this powerful diagnostic tool may soon come into widespread use. Future developments in this and other imaging techniques are likely to have a profound effect on our approach to the diagnosis of periodontal diseases.

Bone turnover markers in serum and periodontal microenvironments

BACKGROUND

Periodontitis is characterized by altered bone turnover, but local measurements are difficult.

OBJECTIVES

The objective of this study was to develop a method to measure multiple markers of bone turnover from single samples collected at various bone surfaces of the periodontium, and to test the ratios of these markers against more traditional serum and gingival crevicular fluid (GCF) samples.

MATERIALS AND METHODS

Fourteen subjects with untreated periodontitis were recruited for sampling serum, GCF (from sites > or = 5 mm probing depth that bled on probing) and washes of periodontal bone surfaces (adjacent interproximal, vestibular cortical and trabecular bone) with a novel irrigating device. All samples were analyzed for osteocalcin (OC, bone turnover marker; RIA), cross-linked N-telopeptide of type I collagen (NTx, bone resorption marker; ELISA) and albumin (Alb, serum protein; ELISA). Results were reported as ratios: OC/NTx to determine relative bone turnover, and OC/Alb or NTx/Alb to determine local OC or NTx production.

RESULTS

The OC/NTx ratio was significantly higher (p < or = 0.05) in serum vs. GCF (OC undetectable), interproximal bone and cortical vestibular bone, but significantly lower than in trabecular vestibular bone. The OC/Alb ratio for serum was also statistically lower than for vestibular trabecular bone. The NTx/Alb ratio for serum was statistically lower than for GCF and all the bone wash test sites. The results indicated considerable local production of both OC and NTx.

CONCLUSIONS

This system demonstrated that multiple markers of bone turnover can be harvested by irrigation from periodontal bone microenvironments. Bone turnover profiles from periodontal bone surfaces and GCF differed from systemic bone turnover profiles (serum) and may be valuable in tracking site-specific responses to disease or treatment.

Elevated levels of collagen cross-link residues in gingival tissues and crevicular fluid of teeth with periodontal disease

Lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) are collagen cross-link residues. Lysylpyridinoline is present in most tissues, whereas LP is present mainly in mineralized tissue. Both are elevated in tissue with increased collagen resorption. The purpose of this investigation was to assess if the concentrations of LP and HP are elevated in gingiva and gingival crevicular fluid (GCF) of teeth with advanced periodontitis (AP). We investigated human gingival biopsies of healthy teeth (n = 19) and teeth with AP (n = 43) in 49 individuals. Samples of GCF from 54 teeth with AP were collected in seven patients and compared with samples from 11 patients with experimentally induced gingivitis. Levels of LP and HP were measured by HPLC and fluorescence detection. Gingival concentrations of HP but not LP around teeth with advanced periodontitis were significantly elevated compared with teeth with healthy periodontium. While significant amounts of HP and LP were measurable in the GCF of teeth with AP, no HP and LP was identified 3 months following non-surgical periodontal therapy of the teeth or in fluid from teeth subjected to experimentally induced gingivitis. Elevated concentrations of HP and LP in GCF may serve as indicators of ongoing destruction of periodontal tissues and alveolar bone in advanced periodontitis.

Mediators of periodontal osseous destruction and remodeling: principles and implications for diagnosis and therapy

Osteoclastic bone resorption is a prominent feature of periodontal disease. Bone resorption via osteoclasts and bone formation via osteoblasts are coupled, and their dysregulation is associated with numerous diseases of the skeletal system. Recent developments in the area of mediators of osteoclastic differentiation have expanded our knowledge of the process of resorption and set the stage for new diagnostic and therapeutic modalities to treat situations of localized bone loss as in periodontal disease. This review describes the current state of knowledge of osteoclast differentiation and activity, mediators, and biochemical markers of bone resorption and their use and potential use in clinical periodontics. Finally, therapeutic strategies based on knowledge gained in the treatment of metabolic bone diseases and in periodontal clinical trials are discussed, and the potential for future strategies is proposed relative to their biologic basis. The intent is to update the field of periodontics on the current state of pathophysiology of the osteoclastic lesion and outline diagnostic and therapeutic strategies with a rational basis in the underlying biology.

Effect of locally delivered minocycline microspheres on markers of bone resorption

BACKGROUND

Gingival crevicular fluid (GCF) biomarkers associated with bone resorption may be useful to determine periodontal disease status and response to therapy. The pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), a bone-specific degradation product, and interleukin 1-beta (IL-1), a potent bone-resorptive cytokine, have both been associated with periodontal disease activity. Minocycline is a tetracycline derivative possessing antimicrobial effects on periodontal pathogens and inhibitory properties on matrix metalloproteinases (MMPs) associated with tissue destruction. The aim of this study was to evaluate the effect of periodontal treatment in the form of scaling and root planing (SRP) and locally administered minocycline microspheres on the GCF levels of ICTP and IL-1.

METHODS

Forty-eight chronic periodontitis patients were randomly assigned to 2 groups (SRP plus subgingival application of vehicle control [SRP + V], or SRP plus subgingival application of minocycline microspheres [SRP + M]) and monitored at 8 sites per subject at baseline and 1, 3, and 6 months. Four shallow (PD < or = 3 mm) and 4 deep (PD > or = 5 mm) sites were evaluated for both marker levels and for probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP). Eight periodontally healthy control subjects with no probing depths >3 mm and no loss of attachment were also monitored at the same time intervals. GCF levels of ICTP and IL-1 were determined using radioimmunoassay and enzyme-linked immunosorbent assay techniques, respectively.

RESULTS

Significant differences (P<0.001) in GCF levels of ICTP and IL-1 were found between deep and shallow sites at all time points in both treatment groups. In addition, healthy subjects demonstrated significantly reduced levels of both markers compared to both shallow and deep sites in periodontitis patients (P <0.001). Only the SRP + M treated patients exhibited significant reductions (P <0.05) in both ICTP and IL-1 levels 1 month after treatment. Furthermore, the SRP + M group demonstrated significantly lower IL-1 levels (P <0.02) at 1 month compared to the SRP + V group.

CONCLUSIONS

Results of this study indicate that GCF levels of ICTP and IL-1 correlate with clinical measures of periodontal disease and may aid in assessing disease status and response to periodontal therapy. Furthermore, local administration of minocycline microspheres led to a potent short-term reduction in GCF IL-1 levels. Additional studies are needed to address whether repeated administration of scaling and root planing along with minocycline microspheres will achieve long-term reductions in GCF ICTP and IL-1 levels.

Effect of non-surgical periodontal therapy on C-telopeptide pyridinoline cross-links (ICTP) and interleukin-1 levels

BACKGROUND

Biochemical markers harvested from gingival crevicular fluid (GCF) may be useful to identify and predict periodontal disease progression and to monitor the response to treatment. C-telopeptide pyridinoline cross-links (ICTP), a host-derived breakdown product specific for bone, and interleukin-1beta (IL-1), a potent bone-resorptive cytokine, have been associated with periodontal tissue destruction. The aim of this study was to examine the effect of non-surgical periodontal therapy on GCF levels of ICTP and IL-1.

METHODS

Twenty-five chronic periodontitis subjects were monitored at 8 sites per subject at baseline prior to scaling and root planing and 1, 3, and 6 months after therapy. Four shallow (probing depths < 4 mm) and 4 deep (probing depths > or = 5 mm) sites were monitored for both marker levels and clinical parameters. GCF was collected for 30 seconds on paper strips, and levels of ICTP and IL-1 were determined using radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques, respectively. Clinical measurements included probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP).

RESULTS

Deep sites exhibited significantly (P<0.001) higher ICTP and IL-1 levels compared to shallow sites at all time intervals. ICTP demonstrated a stronger association to clinical parameters than IL-1 including a modest correlation (r = 0.40, P<0.001) between ICTP and attachment loss. Significant improvements in PD, CAL, and BOP were observed at 1, 3, and 6 months in all sites (P<0.01). However, non-surgical mechanical therapy did not significantly reduce ICTP and IL-1 levels over the 6-month period. Further examination of subjects based on smoking status revealed that ICTP levels were significantly reduced at 3 and 6 months and IL-1 levels reduced at 3 months among non-smokers only.

CONCLUSIONS

A single episode of non-surgical mechanical therapy did not significantly reduce biochemical markers associated with bone resorption in patients exhibiting chronic periodontitis. Future longitudinal studies are warranted to specifically evaluate the relationship between C-telopeptide pyridinoline cross-links and periodontal disease progression.

C-telopeptide pyridinoline cross-links. Sensitive indicators of periodontal tissue destruction

C-telopeptides and related pyridinoline cross-links of bone Type I collagen are sensitive markers of bone resorption in osteolytic diseases such as osteoporosis and osteoarthritis. We have studied the release of C-telopeptide pyridinoline crosslinks of Type I collagen as measures of bone destruction in periodontal disease. Studies in preclinical animal models and humans have demonstrated the relationship between radiographic bone loss and crevicular fluid C-telopeptide levels. We have recently found that C-telopeptide levels correlate strongly with microbial pathogens associated with periodontitis and around endosseous dental implants. Host-modulation of bone-related collagen breakdown has been shown by studies in humans demonstrating that MMP inhibition blocks tissue destruction and release of C-telopeptides in patients with active periodontal disease.

Relationship between C-telopeptide pyridinoline cross-links (ICTP) and putative periodontal pathogens in periodontitis

Crevicular fluid pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) is predictive for future alveolar bone loss in experimental periodontitis in dogs. The present study sought to relate ICTP to a panel of subgingival species in subjects exhibiting various clinical presentations such as health (n=7), gingivitis (n=8) and periodontitis (n=21). 28 subgingival plaque and GCF samples were taken from mesiobuccal sites in each of 36 subjects. The presence and levels of 40 subgingival taxa were determined in plaque samples using whole genomic DNA probes and checkerboard DNA-DNA hybridization. GCF ICTP levels were quantified using radioimmunoassay (RIA). Clinical assessments made at the same sites included: BOP, gingival redness, plaque, pocket depth, and attachment level. Differences among ICTP levels in the 3 subject groups were sought using the Kruskal-Wallis test. Relationships between ICTP levels and clinical parameters as well as subgingival species were determined by regression analysis. The results demonstrated significant differences among disease categories for GCF ICTP levels for healthy (1.1+0.6 pg/site (mean+/-SEM)) gingivitis (14.8+/-6.6 pg/site) and periodontitis subjects (30.3+5.7 pg/site) (p= 0.0017). ICTP levels related modestly to several clinical parameters. Regression analysis indicated that ICTP levels correlated strongly with mean subject levels of several periodontal pathogens including B. forsythus, P. gingivalis, P. intermedia, P. nigrescens and T. denticola (p<0.01). The data indicate that there is a positive relationship between the putative bone resorptive marker ICTP and periodontal pathogens.

Evaluation of components of gingival crevicular fluid as diagnostic tests

Gingival crevicular fluid (GCF) is an inflammatory exudate that can be collected at the gingival margin or within the gingival crevice. The biochemical analysis of the fluid offers a noninvasive means of assessing the host response in periodontal disease. In recent years, the relationship of measures of the inflammatory response in GCF to risk for development of active periodontal disease (defined as clinical attachment loss or radiographic bone loss) has been studied in longitudinal trials. The greatest interest has focused on prostaglandin E2, an arachidonic acid metabolite; beta-glucuronidase and neutrophil elastase, markers of lysosomal enzyme release from neutrophils; and aspartate aminotransferase, a cytoplasmic enzyme indicative of cellular necrosis. Analysis of the data allows a number of conclusions to be drawn concerning the potential diagnostic significance of GCF: 1) an exuberant host inflammatory response is associated with progressive disease in patients with periodontitis; 2) collection of GCF using small precut strips is a reproducible and reliable collection technique; 3) the total amount of the mediator and not concentration of the mediator in the GCF sample can be reported when timed samples are collected; and 4) technology exists for GCF-based diagnostic tests to be performed in the dental office. Nevertheless, many questions remain. Still to be determined are: 1) the relationship of test results to the development of periodontitis in patients with gingivitis; 2) the level of test accuracy needed to justify use of these tests; 3) the unit of observation (patient, site) that is being evaluated by the test; and 4) the need for such tests as perceived by clinicians. While these questions are formidable, introduction of GCF-based diagnostic tests will provide clinicians with an improved, quantitative means of evaluating patients and offer specific criteria to assess the effectiveness of treatment.

The carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) is a potential serum marker of ongoing liver fibrosis

We report for the first time the measurement of the serum concentration of the carboxy-terminal cross-linked telopeptide of type I collagen in patients with various liver diseases. This breakdown product of type I collagen, which is the major collagen type found in fibrotic liver, was measured by a radioimmunoassay in the serum of 149 patients with various liver diseases and in 67 controls. Its concentration is significantly elevated (P < 0.05) above reference intervals in sera from patients with liver diseases, except in patients with chronic active hepatitis of unknown origin and in patients with acute hepatitis A. In the 143 patients with liver fibrosis, the serum level of the carboxy-terminal telopeptide of type I collagen is correlated with the extent of fibrosis, as assessed by a histological scoring system (r = 0.3899, P < 0.0001), but not with inflammation and necrosis.

Analysis in gingival crevicular fluid of two oligopeptides derived from human hemoglobin beta-chain

HPLC on a reversed phase column, amino acid sequencing and mass spectrometry were used to determine the structure of two human gingival crevicular exudate oligopeptides (Leu-Thr-Pro-Glu-Glu-Lys-Ser-Ala-Val-Thr-Ala-Leu and Leu-Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe) which were shown to have been derived from the beta-chain of hemoglobin. These sequences may simply represent two degradation products of the beta-chain. However, their preservation in an exudate characterized by active peptidolysis may also prompt the question about their possible more specific role.

Turnover in periodontal connective tissues: dynamic homeostasis of cells, collagen and ground substances

The connective tissues of the periodontium are composed of two soft tissues and two hard tissues--each of which has unique features. This review considers the constituents of normal, healthy periodontal connective tissues together with an appraisal of the changes in the connective tissue matrices of the periodontium which occur during the development of periodontitis. Recent developments in this field have paved the way for new and exciting vistas in periodontal diagnosis and regeneration which, ultimately, are two important goals in periodontal therapy.

Crevicular fluid osteocalcin and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) as markers of rapid bone turnover in periodontitis. A pilot study in beagle dogs

The objective of this study was to correlate the levels of 2 putative markers of bone metabolism, namely osteocalcin and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), to the progression of experimental alveolar bone loss in the beagle dog. 36 control sites and 36 experimental sites in 2 beagle dogs were assessed longitudinally at 2-week intervals for gingival crevicular fluid (GCF) osteocalcin and ICTP levels during a 6-month observation period. Analysis of osteocalcin and ICTP in GCF was performed by RIA. During the study, bone-seeking radiopharmaceutical uptake (BSRU) of 99mTc-MDP was assessed monthly; standardized radiographs were taken at 2-week intervals. The results showed osteocalcin and ICTP levels in GCF increased significantly (p < 0.05) by 2 weeks following initiation of disease. This increase preceded significant increases in BSRU by 2 weeks and radiographic evidence of bone loss by 4 weeks. BSRU was significantly elevated (p < 0.05) at experimental sites as compared to controls at 4 and 8 weeks post-disease initiation. Osteocalcin in GCF peaked 8 and 10 weeks after ligature placement in experimental sites at levels nearly 10-fold greater than contralateral paired control sites. ICTP levels in GCF remained elevated throughout the entire disease progression phase. Following the removal of ligatures, both GCF osteocalcin and ICTP levels dropped precipitously approaching control values. Osteocalcin revealed overall a positive predictive value (PPV) and negative predictive value (NPV) for future bone loss during disease progression of 0.87 and 0.34, respectively, while ICTP showed both high PPV and NPV of 0.87 and 0.91 respectively. Results from this study in the dog model indicate that osteocalcin and especially ICTP relate to indices of active periodontal bony destruction and suggest that these molecules may serve as predictive markers for future alveolar bone loss.