Effects of tetracyclines on neutrophil, gingival, and salivary collagenases. A functional and western-blot assessment with special reference to their cellular sources in periodontal diseases

Effectiveness of Herbal Medicines with Anti-Inflammatory, Antimicrobial, and Antioxidant Properties in Improving Oral Health and Treating Gingivitis and Periodontitis: A Systematic Review

OBJECTIVES

This systematic review investigates the effectiveness of natural extracts with anti-inflammatory properties for improving oral health, particularly in managing gingivitis and periodontal disease (PD). With PD being a major global health issue, exacerbated by microbial dysbiosis and oxidative stress, the integration of phytochemicals and herbal formulations into periodontal therapy offers a promising avenue for adjunctive treatments.

METHODS

A systematic review was conducted following PRISMA guidelines and registered under the International Prospective Register of Systematic Reviews (ID: 641944). Databases, including PubMed, Scopus, and Web of Science, were searched between 18-24 December 2024, using Boolean keywords combining terms such as "herbal medicine", "plant extracts", "anti-inflammatory", and "periodontal therapy". Studies involving animal models, in vitro data, or non-peer-reviewed articles were excluded.

RESULTS

Seventeen studies met inclusion criteria. Polyherbal formulations and single-component extracts (e.g., Camellia sinensis, Punica granatum, Zingiber officinale, and Rosmarinus officinalis) demonstrated comparable efficacy to conventional agents like chlorhexidine (CHX). Polyherbal rinses, camellia sinensis gels, and extracts like Punica granatum reduced inflammation, improved gingival health, and showed antimicrobial properties, offering effective natural alternatives.

CONCLUSIONS

Natural products, including single extracts and polyherbal formulations, provide effective and safe alternatives for managing gingivitis and PD. Their anti-inflammatory, antimicrobial, and antioxidant properties support their adjunctive role alongside with scaling and root planning therapy (SRP) in periodontal therapy. However, further large-scale, long-term studies are needed to standardize formulations and establish optimal protocols.

aMMP-8 Oral Fluid PoC Test in Relation to Oral and Systemic Diseases

The manuscript uses the previously published literature and highlights the benefits of active-matrix metalloproteinase (aMMP)-8 chairside/point-of-care (PoC) diagnostic tools as adjunctive measures in oral and systemic diseases. Previous studies suggest that as a biomarker, aMMP-8 is more precise than total MMP-8, MMP-9, MMP-2, MMP-3, MMP-13, MMP-7, MMP-1, calprotectin, myeloperoxidase (MPO), human neutrophil elastase (HNE), tissue inhibitor of matrix metalloproteinase (TIMP)-1, and bleeding of probing (BOP). Therefore, aMMP-8 could be implemented as the needed key biomarker for the new disease classification for both periodontitis and peri-implantitis. With a sensitivity to the tune of 75-85% and specificity in the range of 80-90%, lateral flow aMMP-8 PoC testing is comparable to catalytic protease activity assays for aMMP-8. The test can be further applied to estimate the glycemic status of an individual, to ascertain whether a person is at risk for COVID-19, in managing the oral side effects of radiotherapy carried in head and neck cancers, and in selected cases pertaining to reproductive health. In the future, aMMP-8 could find application as a potential systemic biomarker in diseases affecting the cardiovascular system, cancers, bacteremia, sepsis, diabetes, obesity, meningitis, as well as pancreatitis. The aMMP-8 PoCT is the first practical test in the emerging new dental clinical field, that is, oral clinical chemistry representing oral medicine, clinical chemistry, peri-implantology, and periodontology.

Impact of long-term doxycycline on lung function & exacerbations: A real-world open, prospective pilot observation on chronic obstructive pulmonary disease

Background & objectives:

Upregulation of matrix metalloproteinases (MMPs) is related to the pathogenesis of chronic obstructive pulmonary disease (COPD). We aimed at assessing the tolerability and impact of long-term use of MMP inhibitor doxycycline in COPD.

Methods:

A cohort of COPD patients was randomized to continue a uniform COPD treatment with or without add-on long-term oral doxycycline. The lung exacerbations (spirometry), adverse events and health status (COPD Assessment Test score) were noted at 3, 6, 9 and 12 months of therapy. Measurement of the serum MMP-2, and 9 and high-sensitive C-reactive protein (hs-CRP) levels was done at the start of the study and at three months, whenever possible.

Results:

There were 27, 19, 13 and 10 patients with add-on doxycycline group and 22, 19, 11 and 7 patients with COPD treatment alone at 3, 6, 9 and 12 months of treatment respectively. The improvement was obviousaconsistent and serial improvement of health st nd mostly (at 6 and 12 months) significant (P>0.05) for lung function parameters [forced expiratory volume in one second (FEV₁), FEV₁/forced vital capacity (FVC) and forced expiratory flow at 25-75% of FVC (FEF_25-75)] and universal for health status at all measurements, with an overall 26.69 per cent reduction in exacerbations. The analysis with the lung function changes in the available population with protocol violation also supported the same trend. The concomitant reduction in serum MMP-9 (P=0.01), MMP-2 (P=0.01) and hs-CRP (P=0.0001) levels (n=21) at three months was also significant. The adverse reactions with add-on doxycycline appeared acceptable.

Interpretation & conclusions:

Long-term doxycycline appears well tolerated and seems to improve lung function, health status and exacerbations in COPD. The claim needs further scientific validations.

High Expression of MMP-9 in Primary Tumors and High Preoperative MPO in Serum Predict Improved Prognosis in Colorectal Cancer with Operable Liver Metastases

INTRODUCTION

The liver metastases of colorectal cancer (CRC) can be surgically treated in selected cases, with continuously improving results. Matrix metalloproteinases (MMPs) contribute to cancer invasion by degrading the extracellular matrix, and elevated levels of MMP-2, MMP-8, and MMP-9 have been detected in several malignancies. Myeloperoxidase (MPO) is a mediator of tissue damage that can oxidatively activate latent MMPs. We evaluated the prognostic value of MMP-2, MMP-8, and MMP-9 in tissue samples of primary tumors and liver metastases and the pre- and postoperative serum levels of MMP-8, MMP-9, and MPO in CRC patients undergoing liver resection.

METHODS

Tissue and serum samples were obtained from 111 patients who had primary colorectal tumors and their liver metastases surgically treated at the Helsinki University Hospital between 1988 and 2007. Tissue expression of MMP-2, MMP-8, and MMP-9 in primary tumors and liver metastases was evaluated by immunohistochemistry. Pre- and postoperative serum concentrations of MMP-8, MMP-9, and MPO were determined using a time-resolved immunofluorometric assay or commercially available enzyme-linked immunosorbent assay kits. Clinical data were retrieved from patient records and the Central Statistical Office of Finland. Associations with disease-free survival (DFS) and overall survival (OS) were estimated using Cox regression analysis and the Kaplan-Meier method.

RESULTS

High expression of MMP-9 in colorectal tumor tissue was associated with better DFS (p = 0.010), and high preoperative MPO in serum with improved DFS and OS (p < 0.001 and p = 0.014, respectively). The prognostic significance varied according to gender, age, and the synchronicity of liver metastases.

CONCLUSION

Low preoperative MPO in serum might identify patients at high risk of recurrence and death after resection of colorectal liver metastases. Elevated preoperative MPO and high expression of MMP-9 in colorectal tumor tissue indicate an improved prognosis. The use of these biomarkers should be adjusted according to clinical characteristics.

Mechanism and Inhibition of Matrix Metalloproteinases

Matrix metalloproteinases hydrolyze proteins and glycoproteins forming the extracellular matrix, cytokines and growth factors released in the extracellular space, and membrane-bound receptors on the outer cell membrane. The pathological relevance of MMPs has prompted the structural and functional characterization of these enzymes and the development of synthetic inhibitors as possible drug candidates. Recent studies have provided a better understanding of the substrate preference of the different members of the family, and structural data on the mechanism by which these enzymes hydrolyze the substrates. Here, we report the recent advancements in the understanding of the mechanism of collagenolysis and elastolysis, and we discuss the perspectives of new therapeutic strategies for targeting MMPs.

Cathepsin C, Matrix Metalloproteinases, and their Tissue Inhibitors in Gingiva and Gingival Crevicular Fluid from Periodontitis-affected Patients

Successive active phases observed in periodontal diseases may be explained either by a sudden activation of the pro-forms of tissue-stored degradative enzymes such as metalloproteinases (MMPs) or by an imbalance between metalloproteinases and their tissue inhibitors (TIMPs). To discriminate between these two hypotheses, we quantified the levels, the percentage of active form, and the activities of four metalloproteinases (MMPs -1, -2, -3, and -9), as well as the levels of two tissue inhibitors of metalloproteinases (TIMP-1 and -2) and the activity of cathepsin C in tissue extract supernatants and their corresponding gingival crevicular fluid samples collected from periodontitis-affected and healthy patients. Our results supported evidence that tissue destruction results from an imbalance of metalloproteinases over their tissue inhibitors rather than from a sudden activation of the pro-forms of these enzymes. A significant reduction in the activity of cathepsin C also contributed to the degradative process.

The in vivo Levels of Matrix Metalloproteinase-1 and -8 in Gingival Crevicular Fluid during Initial Orthodontic Tooth Movement

Orthodontic force induces biochemical responses in the periodontal ligament (PDL), but the matrix metalloproteinase (MMP)-dependent molecular mechanisms in orthodontically induced periodontal remodeling have remained unclear. Previous studies indicate that mechanical stress induces MMP-1 production in human PDL cells in vitro. We tested the hypothesis whether the in vivo levels, molecular forms, and degree of activation of MMP-1 and MMP-8 in gingival crevicular fluid (GCF) reflect an early stage of orthodontic tooth movement. Molecular forms of MMP-1 and MMP-8 were analyzed by Western blot, and MMP-8 levels by quantitative immunofluoro-metric assay (IFMA). The results showed that GCF MMP-8 levels for orthodontically treated teeth were significantly higher at 4-8 hrs after force application than before activation, and when compared with the control teeth (p < 0.05). Analysis of our data indicates that the cells within the periodontium are up-regulated to produce MMP-8, and the increased expression and activation of GCF MMP-8 reflect enhanced periodontal remodeling induced by orthodontic force.

A novel chemically modified curcumin reduces inflammation-mediated connective tissue breakdown in a rat model of diabetes: periodontal and systemic effects

BACKGROUND AND OBJECTIVE

Periodontal disease is the most common chronic inflammatory disease known to mankind (and the major cause of tooth loss in the adult population) and has also been linked to various systemic diseases, particularly diabetes mellitus. Based on the literature linking periodontal disease with diabetes in a "bidirectional manner", the objectives of the current study were to determine: (i) the effect of a model of periodontitis, complicated by diabetes, on mechanisms of tissue breakdown including bone loss; and (ii) the response of the combination of this local and systemic phenotype to a novel pleiotropic matrix metalloproteinase inhibitor, chemically modified curcumin (CMC) 2.24.

MATERIAL AND METHODS

Diabetes was induced in adult male rats by intravenous injection of streptozotocin (nondiabetic rats served as controls), and Escherichia coli endotoxin (lipopolysaccharide) was repeatedly injected into the gingiva to induce periodontitis. CMC 2.24 was administered by oral gavage (30 mg/kg) daily; untreated diabetic rats received vehicle alone. After 3 wk of treatment, the rats were killed, and gingiva, jaws, tibia and skin were collected. The maxillary jaws and tibia were dissected and radiographed. The gingival tissues of each experimental group (n = 6 rats/group) were pooled, extracted, partially purified and, together with individual skin samples, analyzed for matrix metalloproteinase (MMP)-2 and MMP-9 by gelatin zymography; MMP-8 was analyzed in gingival and skin tissue extracts, and in serum, by western blotting. The levels of three bone-resorptive cytokines [interleukin (IL)-1β, IL-6 and tumor necrosis factor-α], were measured in gingival tissue extracts and serum by ELISA.

RESULTS

Systemic administration of CMC 2.24 to diabetic rats with endotoxin-induced periodontitis significantly inhibited alveolar bone loss and attenuated the severity of local and systemic inflammation. Moreover, this novel tri-ketonic phenylaminocarbonyl curcumin (CMC 2.24) appeared to reduce the pathologically excessive levels of inducible MMPs to near-normal levels, but appeared to have no significant effect on the constitutive MMPs required for physiologic connective tissue turnover. In addition to the beneficial effects on periodontal disease, induced both locally and systemically, CMC 2.24 also favorably affected extra-oral connective tissues, skin and skeletal bone.

CONCLUSION

This study supports our hypothesis that CMC 2.24 is a potential therapeutic pleiotropic MMP inhibitor, with both intracellular and extracellular effects, which reduces local and systemic inflammation and prevents hyperglycemia- and bacteria-induced connective tissue destruction.

A critical role for proinflammatory behavior of smooth muscle cells in hemodynamic initiation of intracranial aneurysm

Background

Intracranial aneurysm initiation is poorly understood, although hemodynamic insult is believed to play an important role in triggering the pathology. It has recently been found in a rabbit model that while macrophages are absent during hemodynamic aneurysm initiation, matrix metalloproteinases (MMPs) are elevated and co-localize with smooth muscle cells (SMCs). This study investigates whether SMCs play a mechanistic role in aneurysm initiation triggered by hemodynamics.

Methods

Aneurysmal damage was induced at the basilar terminus via bilateral common carotid artery ligation in rabbits (n = 45, plus 7 sham controls). 16 ligated rabbits were treated with doxycycline to inhibit MMPs, 7 received clodronate liposomes to deplete circulating monocytes, and the rest received no drug. Effects of the treatments on aneurysm development were assessed histologically 5 days and 6 months after ligation. MMP production and expression of inflammatory markers by SMCs was monitored by immunohistochemistry and in situ hybridization.

Results

Treatment with doxycycline attenuated aneurysmal development examined at 5 days and 6 months, suggesting that MMPs contribute to aneurysm initiation. However, systemic depletion of macrophages did not decrease MMPs or suppress aneurysmal development. Immunofluorescence showed that during aneurysm initiation MMP-2 and MMP-9 were distributed in SMCs, and in situ hybridization indicated that they were transcribed by SMCs. In regions of early aneurysmal lesion, SMCs exhibited decreased expression of smooth muscle actin and increased NF-κB and MCP-1 expressions.

Conclusions

During aneurysm initiation triggered by hemodynamics, SMCs rather than macrophages are responsible for MMP production that is critical for aneurysmal lesion development. These SMCs exhibit proinflammatory behavior.

Salivary MMPs, TIMPs, and MPO levels in periodontal disease patients and controls

BACKGROUND

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases with an important role in physiological and pathological remodeling. Their activity is regulated by tissue inhibitors of matrix metalloproteinases (TIMPs). Excess MMPs and myeloperoxidase (MPO) activity have been associated with loss of tooth supporting tissues in periodontal disease (PD). We investigate the changes in salivary MMP-8, MMP-9, TIMP-1, TIMP-2, and MPO concentrations during PD treatment and compare results with plasma levels.

METHODS

MMP-8, MMP-9, TIMP-1 and TIMP-2 were analyzed by ELISA. Gelatinolytic activity of MMP-9 forms was determined by zymography, and the MPO activity was determined by colorimetric assay.

RESULTS

Subjects were divided into 2 groups: PD and control, which were further divided into 2 subgroups each, namely PD before (PB) and after 3 months (PA) of non-surgical periodontal therapy, and healthy volunteers at baseline (CB) and 3months after baseline (CA). Subgroup PA presented lower gelatinolytic activity and MMP-8 and TIMP-2 concentrations in the saliva compared with PB (p<0.05). The MPO activity was higher in PB compared with CB (p<0.05). There were significant correlations between the gelatinolytic activity of the saliva and MMP-8 and MMP-9 plasma levels. There was a significant correlation between plasma and saliva TIMP-2 levels.

CONCLUSION

These results suggest attenuation of some inflammatory markers in the saliva and plasma after PD treatment. Moreover, correlations between salivary and plasma levels exist for some of these markers.

Lack of MMP-9 expression is a marker for poor prognosis in Dukes' B colorectal cancer

Background

Matrix metalloproteinases (MMPs) play a role in cancer progression by degrading extracellular matrix and basement membranes, assisting in tumour neovascularization and in supporting immune response in cancer.

Methods

We studied the prognostic value of immunohistochemical expression of MMP-2, MMP-8, and MMP-9 in a series of 619 colorectal cancer patients using tissue microarray specimens.

Results

Of the samples, 56% were positive for MMP-2, 78% for MMP-8, and 60% for MMP-9. MMP-9 associated with low WHO grade (p < 0.001). In univariate analysis of Dukes’ B tumours, MMP-9 negativity associated with poor survival (p = 0.018), and MMP-9 positivity was an independent prognostic marker in multivariate analysis of these tumours (p = 0.034).

Conclusion

Negative MMP-9 expression can predict poor prognosis in Dukes’ B colorectal tumours and may prove useful for identifying patients, who should be offered adjuvant treatment.

The enhanced permeability retention effect: a new paradigm for drug targeting in infection

Multidrug-resistant, Gram-negative infection is a major global determinant of morbidity, mortality and cost of care. The advent of nanomedicine has enabled tailored engineering of macromolecular constructs, permitting increasingly selective targeting, alteration of volume of distribution and activity/toxicity. Macromolecules tend to passively and preferentially accumulate at sites of enhanced vascular permeability and are then retained. This enhanced permeability and retention (EPR) effect, whilst recognized as a major breakthrough in anti-tumoral targeting, has not yet been fully exploited in infection. Shared pathophysiological pathways in both cancer and infection are evident and a number of novel nanomedicines have shown promise in selective, passive, size-mediated targeting to infection. This review describes the similarities and parallels in pathophysiological pathways at molecular, cellular and circulatory levels between inflammation/infection and cancer therapy, where use of this principle has been established.

Matrix metalloproteinase-8/collagenase-2 in childhood otitis media with effusion

BACKGROUND

Matrix metalloproteinases (MMPs), gelatinases, have been associated with otitis media with effusion (OME), but the role of collagenase-2/matrix metalloproteinase-8 (MMP-8) in OME has not been studied previously. We studied the levels, isoenzyme distribution, and activation of MMP-8 in childhood OME, and also the levels of pro- and active forms of MMP-2 and -9 as well as 120 kDa gelatinase complexes were assessed.

METHODS

Seventy middle ear fluid (MEF) samples were collected from 54 children with OME and classified to mucoid (n = 39) or serous (n = 31). MMPs were studied from MEF samples by time-resolved immunofluorometric assay, Western immunoblotting, and gelatin-zymography.

RESULTS

MMP-8 was found in its active form in MEF of children with OME. MMP-8 levels were significantly higher in mucous relative to serous OME. The pro- or active MMP-2 and -9 were found in MEF, but no MEF type-specific differences were found.

CONCLUSION

Our results suggest that MMP-8 may play a role in the pathogenesis of childhood OME. New therapeutic strategies with MMP inhibitors targeting MMP-8, but allowing MMP-8 to carry out the protective action, may play a role in the future treatment of otitis media and OME. However, further studies of this topic are needed.

Oral doxycycline for the treatment of chronic leg ulceration

This pilot study investigated oral doxycycline as an adjunct to compression therapy for non-healing venous leg ulcers. Ten patients received doxycycline 20 mg twice daily (low-dose doxycycline) and ten patients received doxycycline 100 mg twice daily (high-dose doxycycline). Utilising a pre-test post-test study design, ulcer area was measured and wound fluid was collected before and after 4 weeks of treatment. In the high-dose doxycycline group, the reduction in median ulcer area was 48% (p = 0.1) and there was a significant reduction in wound fluid total matrix metalloprotease-1 (p = 0.02). These effects were not observed with low-dose doxycycline. There were no significant changes in wound fluid tumour necrosis factor-α or quantitative bacteriology following treatment with low-dose or high-dose doxycycline. There was no significant relationship between change in ulcer area and matrix metalloprotease-1, -8 or -9 activities in wound fluid at the end of treatment. Median wound fluid doxycycline concentrations after 4 weeks of treatment were 0.2 mg/L(0.45 lM) and 2.3 mg/L (5.18 lM) [DOSAGE ERROR CORRECTED] in the low-dose and high-dose groups, respectively, which are lower than that previously shown to inhibit matrix metalloproteases and tumour necrosis factor-α. Our study suggests that doxycycline 100 mg twice daily may improve the healing rate of recalcitrant leg ulcers, however the mechanism remains unclear.

Salivary biomarkers of periodontal disease in response to treatment

BACKGROUND

Salivary biomarkers of periodontitis were assessed longitudinally to determine response to therapy.

METHODS

A 6-month case-controlled study of adults with chronic periodontitis was performed, with 33 participants receiving oral hygiene instructions (OHI) alone and 35 with scaling and root planing (SRP) combined with OHI. Saliva samples collected at week 0, 16 and 28 were analysed for interleukin (IL)-1β, IL-8, macrophage inflammatory protein (MIP)-1α, matrix metalloproteinase-8 (MMP-8), osteoprotegerin (OPG), and tumour necrosis factor-α (TNF)-α. Clinical measures of periodontal disease were recorded at each visit.

RESULTS

All parameters of periodontal health improved significantly in both groups by week 16 (p<0.0001) with the SRP group demonstrating greater benefit at week 16 and 28. Baseline OPG and TNF-α levels changed significantly at both follow-up visits (p<0.03), regardless of treatment group. IL-1β and MMP-8 levels decreased significantly from baseline (p<0.04) in the SRP group only. OPG, MMP-8, and MIP-1α were significantly reduced in responders compared with non-responders (p=0.04, 0.01, 0.05, respectively). In receiver-operating characteristic analyses, MMP-8 produced the highest area under the curve (0.7; p=0.01).

CONCLUSION

Salivary levels of IL-1β, MMP-8, OPG, and MIP-1α reflected disease severity and response to therapy suggesting their potential utility for monitoring periodontal disease status.

Tetracycline compounds with non-antimicrobial organ protective properties: possible mechanisms of action

Tetracyclines were developed as a result of the screening of soil samples for antibiotics. The first(t) of these compounds, chlortetracycline, was introduced in 1947. Tetracyclines were found to be highly effective against various pathogens including rickettsiae, as well as both gram-positive and gram-negative bacteria, thus becoming the first class of broad-spectrum antibiotics. Many other interesting properties, unrelated to their antibiotic activity, have been identified for tetracyclines which have led to widely divergent experimental and clinical uses. For example, tetracyclines are also an effective anti-malarial drug. Minocycline, which can readily cross cell membranes, is known to be a potent anti-apoptotic agent. Another tetracycline, doxycycline is known to exert anti-protease activities. Doxycycline can inhibit matrix metalloproteinases which contribute to tissue destruction activities in diseases such as periodontitis. A large body of literature has provided additional evidence for the "beneficial" actions of tetracyclines, including their ability to act as reactive oxygen species scavengers and anti-inflammatory agents. This review provides a summary of tetracycline's multiple mechanisms of action as a means to understand their beneficial effects.

Rheumatoid arthritis and salivary biomarkers of periodontal disease

AIM

To test the hypothesis that rheumatoid arthritis (RA) influenced levels of salivary biomarkers of periodontal disease.

METHODS

Medical assessments, periodontal examinations and pain ratings were obtained from 35 RA, 35 chronic periodontitis and 35 age- and gender-matched healthy controls in a cross-sectional, case-controlled study. Unstimulated whole saliva samples were analysed for interleukin-1β (IL-1β), matrix metalloproteinase-8 (MMP-8) and tumour necrosis factor-α (TNF-α) concentrations.

RESULTS

The arthritis and healthy groups had significantly less oral disease than the periodontitis group (P<0.0001), with the arthritis group having significantly more sites bleeding on probing (BOP) than matched controls (P=0.012). Salivary levels of MMP-8 and IL-1β were significantly elevated in the periodontal disease group (P<0.002), and IL-1β was the only biomarker with significantly higher levels in the arthritis group compared with controls (P=0.002). Arthritis patients receiving anti-TNF-α antibody therapy had significantly lower IL-1β and TNF-α levels compared with arthritis patients not on anti-TNF-α therapy (P=0.016, 0.024) and healthy controls (P<0.001, P=0.011), respectively.

CONCLUSION

RA patients have higher levels of periodontal inflammation than healthy controls, i.e., an increased BOP. Systemic inflammation appears to influence levels of select salivary biomarkers of periodontal disease, and anti-TNF-α antibody-based disease-modifying therapy significantly lowers salivary IL-1β and TNF-α levels in RA.

Tetracyclines: a pleitropic family of compounds with promising therapeutic properties. Review of the literature

There must be something unique about a class of drugs (discovered and developed in the mid-1940s) where there are more than 130 ongoing clinical trials currently listed. Tetracyclines were developed as a result of the screening of soil samples for antibiotic organisms. The first of these compounds chlortetracycline was introduced in 1948. Soon after their development tetracyclines were found to be highly effective against various pathogens including rickettsiae, Gram-positive, and Gram-negative bacteria, thus, becoming a class of broad-spectrum antibiotics. The mechanism of action of tetracyclines is thought to be related to the inhibition of protein synthesis by binding to the 30S bacterial ribosome. Tetracyclines are also an effective anti-malarial drug. Over time, many other "protective" actions have been described for tetracyclines. Minocycline, which can readily cross cell membranes, is known to be a potent anti-apoptotic agent. Its mechanism of action appears to relate to specific effects exerted on apoptosis signaling pathways. Another tetracycline, doxycycline is known to exert antiprotease activities. Doxycycline can inhibit matrix metalloproteinases, which contribute to tissue destruction activities in diseases such as gingivitis. A large body of literature has provided additional evidence for the "beneficial" actions of tetracyclines, including their ability to act as oxygen radical scavengers and anti-inflammatory agents. This increasing volume of published work and ongoing clinical trials supports the notion that a more systematic examination of their possible therapeutic uses is warranted. This review provides a summary of tetracycline's multiple mechanisms of action and while using the effects on the heart as an example, this review also notes their potential to benefit patients suffering from various pathologies such as cancer, Rosacea, and Parkinson's disease.

Clinical and biochemical efficacy of minocycline in nonsurgical periodontal therapy: a randomized controlled pilot study

The present study evaluated the effects of systemic minocycline on clinical and biochemical parameters of chronic periodontitis, which is a common inflammatory disorder of the periodontium initiated by the presence of bacteria in the gingival sulcus. Besides nonsurgical periodontal therapy, 20 individuals received minocycline systemically while another 20 subjects received placebo capsules for 2 weeks. Plaque index (PI), sulcus bleeding index (SBI), probing depth (PD), and relative attachment level (RAL) were measured and gingival crevicular fluid (GCF) samples were obtained at baseline and first, third, and sixth months. Matrix metalloproteinase-8 (MMP-8) and prostaglandin E₂ (PGE₂) levels were analyzed by enzyme immunoassay method. Significant improvements in all parameters in both groups were recorded. In the minocycline group, changes in PI and SBI were significantly greater only at first month, whereas reductions in PD, RAL, MMP-8, and PGE₂ levels were greater at all times. MMP-8 and PGE₂ exhibited positive correlations with SBI, PD, and each other. Minocycline demonstrated clinical benefit for periodontal therapy and provided further improvements on inflammatory mediators promising a host-modulating capacity.

Current developments in salivary diagnostics

Salivary diagnostics is an emerging field that has progressed through several important developments in the past decade, including the publication of the human salivary proteome and the infusion of federal funds to integrate nanotechnologies and microfluidic engineering concepts into developing compact point-of-care devices for rapid analysis of this secretion. In this article, we discuss some of these developments and their relevance to the prognosis, diagnosis and management of periodontitis, as an oral target, and cardiovascular disease, as a systemic example for the potential of these biodiagnostics. Our findings suggest that several biomarkers are associated with distinct biological stages of these diseases and demonstrate promise as practical biomarkers in identifying and managing periodontal disease, and acute myocardial infarction. The majority of these studies have progressed through biomarker discovery, with the identified molecules requiring more robust clinical studies to enable substantive validation for disease diagnosis. It is predicted that with continued advances in this field the use of a combination of biomarkers in multiplex panels is likely to yield accurate screening tools for these diagnoses in the near future.

Doxycycline-mediated inhibition of choroidal neovascularization

PURPOSE

Doxycycline, a broad-spectrum antibiotic, has certain antiangiogenic properties and can inhibit matrix metalloproteinases (MMPs/gelatinases). The authors investigated the effects of doxycycline on choroidal neovascularization (CNV) and regulation of MMP-2 and -9 and pigment epithelium-derived factor (PEDF).

METHODS

Doxycycline was orally administered to rats at 500, 50, 5, and 0.5 mg/kg/d; nontreated animals were used as controls. Experimental CNV was induced with laser 7 days after doxycycline treatment started. At 7 days after induction, animals were euthanatized, and eyes were collected. RPE/choroid flatmounts were labeled with isolectin IB4 to determine CNV lesion volumes using confocal microscopy and high-performance 3D imaging software. MMP-2, MMP-9, and PEDF protein levels were determined by ELISA. MMP catalytic activity was determined in solution using fluorogenic gelatin and peptide substrates, by gelatin zymography in SDS-PAGE, and by in situ fluorogenic substrate zymography in RPE/choroid sections.

RESULTS

CNV complex lesion volumes decreased with doxycycline in a dose-response relationship. A dosage of 500 mg/kg/d caused a 70% inhibition of CNV complex volume compared with control animals. Doxycycline elevated PEDF levels in plasma and did not affect the active and pro-enzymes MMP-2 and MMP-9 levels. However, the in vitro enzymatic activities of purified MMP-2 and MMP-9 declined significantly with doxycycline. MMP-2, MMP-9, and gelatinolytic activities in situ increased early in CNV lesion development. Doxycycline treatments and exogenous additions inhibited gelatinolytic activities in CNV lesions.

CONCLUSIONS

Doxycycline effectively hampered the progression of experimental CNV. The results suggest that orally administrated doxycycline can reach the choroid to attenuate proteolytic enzymes that remodel Bruch's membrane and promote the antiangiogenic PEDF to inhibit neovascularization.

Doxycycline causes regression of endometriotic implants: a rat model

BACKGROUND

Doxycycline (Dox) has a number of non-antibiotic properties. One of them is the inhibition of matrix metalloproteinase (MMP) activity. The aim of this study was to assess the effects of Dox in a rat endometriosis model.

METHODS

Endometriosis was surgically induced in 40 rats by transplanting of endometrial tissue. After 3 weeks, repeat laparotomies were performed to check the implants and the animals were randomized into four groups: Group I, low-dose Dox (5 mg/kg/day); Group II, high-dose Dox (40 mg/kg/day); Group III, leuprolide acetate 1 mg/kg single dose, s.c.; and Group VI (controls), no medication. The treatment, initiated on the day of surgery and continuing for 3 weeks, was administered to the study groups. Three weeks later, the rats were euthanized and the implants were evaluated morphologically and histologically for immunoreactivity of MMP-2 and -9, and interleukin-6 (IL-6) concentration in the peritoneal fluid was assayed.

RESULTS

Treatment with leuprolide acetate, or high-dose or low-dose Dox caused significant decreases in the implant areas compared with the controls (P = 0.03, P = 0.006, and P = 0.001, respectively). IL-6 levels in peritoneal fluid decreased in Group I (P = 0.02) and Group III (P < 0.05). MMP H scores were significantly lower in the group that received low-dose Dox in both epithelial and stromal MMP-2 and -9 immunostaining when compared with the control group [P = 0.048, P = 0.002, P = 0.007 and P = 0.002, respectively, MMP-2 (epithelia), MMP-2 (stroma), MMP-9 (epithelia) and MMP-9 (stroma)].

CONCLUSIONS

Low-dose Dox caused regression of endometriosis in this experimental rat model.

Short term effects of doxycycline on matrix metalloproteinases 2 and 9

PURPOSE

To investigate the short term effects of Doxycycline on MMP-2 and MMP-9.

METHODS

Short term effects of Doxycycline (100 mg B.I.D.) on plasma levels of MMP-2 and MMP-9 were investigated in 20 healthy subjects; the effects of Doxy, Acetylsalicylic acid, Nitrates, and Enalapril on MMP-9 release from were assessed in isolated polymorphonuclear cells.

RESULTS

In plasma, MMP-9 activity was reduced (-22%, 95% CI -32/-11; P = 0.002) starting at 12 h after doxy; in vitro, MMP-9 released from stimulated neutrophils was reduced by Doxy (-28%, 95% CI -43/-14; P = 0.001), inhibiting degranulation, and by nitrates (-52%, 95% CI -76/-28 P = 0.005), increasing three times both pro- and active-MMP-9 bound to neutrophils (P = 0.007 and 0.040, respectively).

CONCLUSIONS

Doxy decreases MMP-9 plasma levels by around 20%, within the first 12 h. The mechanism leading to such reduction seems due to the inhibition of PMN degranulation.

Tear fluid concentration of mmp-8 is elevated in non-allergic eosinophilic conjunctivitis and correlates with conjunctival inflammatory cell infiltration

BACKGROUND

To investigate tear fluid concentration of matrix metalloproteinase 8 (MMP-8) and its relation to conjunctival inflammatory cell infiltration in persistent non-allergic eosinophilic conjunctivitis (NAEC).

METHODS

Two groups were included: 26 consecutive adult patients with NAEC (conjunctival eosinophils at least 1+ [1-10 eosinophils/slide], skin prick test [SPT] to common allergens negative), and 26 asymptomatic adult persons (no conjunctival eosinophils, SPT negative). MMP-8 tear fluid concentrations were determined by immunofluorometric assay, and conjunctival brush cytology samples from NAEC patients were used for MMP-8 immunocytochemistry. Gelatin zymography was used to illustrate proteolytic activity within the tear fluid samples.

RESULTS

The mean MMP-8 concentration was significantly higher among NAEC patients (214.3 +/- 327.7 microg/l) than among healthy persons (50.4 +/- 62.3 microg/l, P < 0.0001). In the NAEC patients, tear fluid MMP-8 correlated with the numbers of conjunctival neutrophils (r = 0.66, P = 0.0002) as well as with goblet cells and columnar epithelial cells (r = 0.54 for both, P = 0.045), but not with the lymphocyte numbers (r = -0.36, P = 0.0741). By immunocytology, MMP-8 protein could also be detected in vivo in the inflammatory cell population within the conjunctiva. Zymography revealed that proteolysis was significantly higher in the NAEC group, and activated enzymes were practically found only in the NAEC group.

CONCLUSIONS

The results showed that NAEC is an inflammatory condition characterized by increased tear fluid MMP-8 levels, probably derived from both inflammatory and structural conjunctival cells. The increased proteolytic activity in NAEC patients may indicate risk of conjunctival structural changes (remodeling).

Fas-ligand-induced apoptosis of respiratory epithelial cells causes disruption of postcanalicular alveolar development

Premature infants are at risk for bronchopulmonary dysplasia, a complex condition characterized by impaired alveolar development and increased alveolar epithelial apoptosis. The functional involvement of pulmonary apoptosis in bronchopulmonary dysplasia- associated alveolar disruption remains undetermined. The aims of this study were to generate conditional lung-specific Fas-ligand (FasL) transgenic mice and to determine the effects of FasL-induced respiratory epithelial apoptosis on alveolar remodeling in postcanalicular lungs. Transgenic (TetOp)(7)-FasL responder mice, generated by pronuclear microinjection, were bred with Clara cell secretory protein (CCSP)-rtTA activator mice. Doxycycline (Dox) was administered from embryonal day 14 to postnatal day 7, and lungs were studied between embryonal day 19 and postnatal day 21. Dox administration induced marked respiratory epithelium-specific FasL mRNA and protein up-regulation in double-transgenic CCSP-rtTA(+)/(TetOp)(7)-FasL(+) mice compared with single-transgenic CCSP-rtTA(+) littermates. The Dox-induced FasL up-regulation was associated with dramatically increased apoptosis of alveolar type II cells and Clara cells, disrupted alveolar development, decreased vascular density, and increased postnatal lethality. These data demonstrate that FasL-induced alveolar epithelial apoptosis during postcanalicular lung remodeling is sufficient to disrupt alveolar development after birth. The availability of inducible lung-specific FasL transgenic mice will facilitate studies of the role of apoptosis in normal and disrupted alveologenesis and may lead to novel therapeutic approaches for perinatal and adult pulmonary diseases characterized by dysregulated apoptosis.

Fibronectin fragmentation is a feature of periodontal disease sites and diabetic foot and leg wounds and modifies cell behavior

BACKGROUND

Fibronectin (FN) undergoes fragmentation in periodontal disease sites and in poorly healing diabetic wounds. The biologic effects of FN fragments on wound healing remain unresolved. This study characterized the pattern of FN fragmentation and its effects on cellular behavior compared to intact FN.

METHODS

Polyclonal antibodies were raised against FN and three defined recombinant segments of FN and used to analyze gingival crevicular fluid from periodontal disease sites in systemically healthy subjects and in subjects with diabetes, as well as chronic leg and foot wound exudates from subjects with diabetes. Subsequently, the behavior of human gingival fibroblasts (hGFs) and HT1080 reference cells were analyzed by measuring cell attachment, migration, and chemotaxis in the presence of intact FN or recombinant FN fragments.

RESULTS

FN fragmentation was evident in fluids from periodontal disease sites and diabetic leg and foot wounds. However, no fragmentation pattern distinguished systemically healthy subjects from subjects with diabetes. hGFs and HT1080 cells required significantly higher concentrations of FN fragments to achieve attachment comparable to intact FN. Cells cultured on FN fragments also were morphologically different from cells cultured on full-length FN. Migration was reduced for hGFs cultured on FN fragments relative to full-length FN. In contrast, FN fragments increased HT1080 fibrosarcoma cell migration over intact FN.

CONCLUSIONS

FN fragmentation is a prominent feature of periodontal and chronic leg and foot wounds in diabetes. Furthermore, cell culture assays confirmed the hypothesis that exposure to defined FN fragments significantly alters cell behavior.

Urinary matrix metalloproteinase -8, -9, -14 and their regulators (TRY-1, TRY-2, TATI) in patients with diabetic nephropathy

Matrix metalloproteinase-9 (MMP-9) has been shown to be involved in the development of diabetic nephropathy (DNP). We studied the levels, molecular forms, and degree of activation of urinary MMP-8, -9, -14, trypsin-1 and -2, as well as tumor-associated trypsin inhibitor (TATI) of DNP patients and healthy controls. Urinary samples were analyzed for MMPs by Western blotting and gelatin zymography and for trypsin-1, -2, and TATI by time-resolved immunofluorometric assays. Total MMP-8 immunoreactivity, the proportion of active MMP-9, and gelatinolytic activity in urine were significantly higher in DNP patients than in controls. In urine of DNP patients the proportion of active polymorphonuclear neutrophil (PMN)-type (but not fibroblast-type) MMP-8 was increased. MMP-8 and MMP-9 were found to form high molecular weight complexes in DNP urine. Total immunoreactivity of soluble urinary MMP-14 and the levels of trypsin (TRY)-1 and TRY-2, but not of TATI, were also significantly increased in DNP. Zymography, Western blotting, and immunofluorometric analysis of DNP urine showed a significant association especially between activation of MMP-9 as well as PMN-type MMP-8 and TRY-2. Our findings suggest that a trypsin-MMP cascade is involved in the pathogenesis of DNP, which may offer new possibilities for diagnosis and treatment of DNP with MMP inhibitors.

CMT-3 inhibits orthodontic tooth displacement in the rat

OBJECTIVE

Orthodontic tooth movement requires extensive remodeling of the periodontal ligament (PDL) and the alveolar bone. Osteoclasts resorb bone, allowing teeth to migrate in the direction of the force. Matrix metalloproteinases (MMPs) are able to degrade the extracellular matrix of the periodontal tissues. Chemically modified tetracyclines (CMTs) can inhibit MMPs, but lack antimicrobial activity. We hypothesize that CMT-3 will decrease the rate of orthodontic tooth movement in the rat.

DESIGN

Eighteen Wistar rats received a standardized orthodontic appliance at one side of the maxilla. During 14 days, three groups of six rats received a daily dose of 0, 6 or 30mg/kg CMT-3, and tooth displacement was measured. Thereafter, osteoclasts were counted on histological sections using an ED-1 staining. Multi- and mononuclear ED-1-positive cells in the PDL were also counted. In addition, sections were stained for MMP-9.

RESULTS

CMT-3 significantly inhibited tooth movement (p=0.03) and also decreased the number of osteoclasts at the compression sides in the 30mg/kg group (p<0.05). Significantly more mono- than multinuclear ED-1-positive cells were present in the PDL, but no significant differences were found between the dosage groups. Osteoclasts in the 30mg/kg group seemed to contain less MMP-9 than in the control.

CONCLUSIONS

CMT-3 inhibits tooth movement in the rat, probably by reducing the number of osteoclasts at the compression side. This might be due to induction of apoptosis in activated osteoclasts or reduced osteoclast migration. Reduced MMP activity by CMT-3 might also directly inhibit degradation of the organic bone matrix.

Matrix metalloproteinase-7, -8, -9, -25, and -26 and CD43, -45, and -68 cell-markers in HIV-infected patients' saliva and gingival tissue

BACKGROUND

Matrix metalloproteinases (MMPs) process the extracellular matrix and act in tissue remodelling in many physiological and pathological conditions. Certain MMPs can also exert protective anti-inflammatory properties. The levels and expression of MMPs and tissue inhibitors of MMPs (TIMPs) in saliva and gingival tissues of human immunodeficiency virus-seropositive (HIV+) patients are unclear.

METHODS

Enzyme-linked immunosorbent assay methods and Western blots were used to study levels and molecular forms of MMP-7, -8, -9, -25, and -26 and TIMP-1 from salivary samples of HIV+ patients (n = 55) and healthy controls (n = 10). The expression of MMPs was also studied by immunohistochemical means in gingival tissue specimens (n = 11, HIV+ patients; n = 10, healthy controls).

RESULTS

The HIV+ patients' MMP-8 levels in saliva were statistically significantly higher only in the acquired immunodeficiency syndrome (AIDS)-phase. MMP-9 levels in ASX- and AIDS-phases showed increased expression. TIMP-1 levels were significantly decreased in lymphadenopathy syndrome (LAS)- and AIDS-related complex (ARC)-phases, while MMP-8/TIMP-1 and MMP-9/TIMP-1 molar ratios were increased in all phases in comparison with controls. The molecular forms of MMP-7, -25, and -26 were different between patients and controls as assessed by Western blot. Immunohistochemical studies showed slightly enhanced MMP-7, -8, -9, -25, and -26 staining in HIV+ gingival tissue samples in comparison with controls.

CONCLUSIONS

This study confirmed and further demonstrated differences in salivary amounts and molecular forms of MMPs and TIMP-1 in HIV+ patients. The results may reflect alterations in host defence reactions associated with HIV infection.

Chemically modified tetracyclines stimulate matrix metalloproteinase-2 production by periodontal ligament cells

BACKGROUND AND OBJECTIVE

The purpose of this study was to investigate the effects of chemically modified tetracyclines (CMTs) on the production of gelatinases [matrix metalloproteinase (MMP)-2 and -9] by human periodontal ligament (PDL) cells, and on the activity of recombinant gelatinases.

MATERIAL AND METHODS

Human PDL cells were cultured with CMT-1, -3, -5, -7 or -8 in concentrations of 0, 1, 5, 10, 20, 50, 100, 200 and 500 microm. Gelatin zymography was used to determine MMP-2 and -9 production of the cells. The amount of DNA present in the cultures was analyzed using a fluorescent assay. The cytotoxicity of the CMTs was also determined. Recombinant human MMP-2 and -9 were incubated with the CMTs (0-500 microm) and their activity was analyzed using an internally quenched fluorogenic substrate.

RESULTS

MMP-2 production was stimulated up to sevenfold by CMT-1, -3, -7 and -8 at low concentrations (10-200 microm). No significant amounts of MMP-9 were produced. In contrast, MMP-2 and -9 activity was reduced by approximately 10-40-fold at higher concentrations (200-500 microm). CMT-5 had no effect on the production or on the activity of MMP-2 and -9. Only CMT-3 and -8 had cytotoxic effects on the PDL cells at the highest concentrations.

CONCLUSION

Surprisingly, CMTs are able to stimulate MMP-2 production at relatively low concentrations. However, at higher concentrations they exert a much stronger inhibitory effect on gelatinase activity. A possible stimulatory effect of CMTs on MMP production should be considered in their clinical use.

Levels and Activation of Matrix Metalloproteinases in Aqueous Humor Are Elevated in Uveitis-Related Secondary Glaucoma

PURPOSE

To measure the levels of matrix metalloproteinase (MMP)-2 and tissue inhibitors of metalloproteinases (TIMP)-2 and to study the expression pattern and molecular forms of MMP-2, 8, 9, 13, and 14 and TIMP-1 and 2 in aqueous humor samples in cases of uveitis-related secondary glaucoma (USG) with a history of up to 20 years by comparison with primary open-angle glaucoma (POAG) and cataracts.

METHODS

33 aqueous humor samples were collected during intraocular surgery. MMP-2 and TIMP-2 levels were analyzed by enzyme-linked immunosorbent assay. Molecular forms and activation degrees of MMPs and TIMPs were analyzed by Western immunoblotting and zymography. The results were related to the clinical data.

RESULTS

Enzyme-linked immunosorbent assay measurements of both MMP-2 and TIMP-2 were statistically significantly increased in the USG samples relative to POAG and cataracts (P=0.002). In Western blotting all the MMPs showed increased expression and conversion to their active forms in USG, whereas in the POAG and cataract samples MMPs were found mainly in their latent forms. MMP-8, 9, 13, and 14 showed statistically significantly elevated expression in USG relative to POAG and cataracts on densitometric scanning of Western blots. On zymography, MMP-2 and 9 activation was significantly enhanced in USG compared with POAG and cataracts.

CONCLUSIONS

Increased expression of MMPs and their conversion to active forms is characteristics of the aqueous humor in USG, even with a very long history. This emphasizes the fact that increased MMP expression reflects inflammatory disease activity and is probably associated with the development of USG and its complications. Although intraocular pressure is elevated in both glaucoma types, MMP expression in POAG more closely resembles that in cataracts, and therefore the role of MMPs in USG differs very markedly from that in POAG.

Tear fluid levels of MMP-8 are elevated in ocular rosacea--treatment effect of oral doxycycline

BACKGROUND

Ocular rosacea (OcR) is a chronic inflammatory disease especially affecting lid margins. Previous studies have shown that it is accompanied by increased levels and activation of tear fluid gelatinases. Matrix metalloproteinase 8 (MMP-8; collagenase 2) levels and activation are commonly elevated in many inflammatory conditions. Therefore we studied here whether MMP-8 concentration and activation in tear fluid are increased also in OcR, and if an oral doxycycline regimen could rectify the situation.

METHODS

Tear fluid samples were collected from 22 OcR patients and 22 healthy controls. The OcR patients were then treated with an oral doxycycline regimen for 8 weeks and tear fluid samples collected again after 4 and 8 weeks. Conjunctival brush cytology and patients' subjective symptoms were scored. MMP-8 concentrations in the tear fluid were assessed by immunofluorometric assay and the molecular forms and isoenzyme expression of MMP-8 were studied by Western immunoblotting.

RESULTS

The mean MMP-8 concentration was statistically significantly higher in OcR (156.8+/-207.4 mug/ml) than in the normal subjects (53.5+/-66.7 mug/ml) (P=0.036), but decreased to 79.2+/-141.6 mug/l and 53.6+/-75.2 mug/l after 4 and 8 weeks doxycycline treatment, respectively. There was a statistically significant difference between the untreated OcR and the MMP-8 results after 4 or 8 weeks of oral doxycycline (P=0.041 and 0.069, respectively) and the OcR patients experienced statistically significant relief of their subjective symptoms (P=0.0001) after the doxycycline regimen. Both the normal and OcR tear fluid contained the larger, 60-80 kDa highly- glycosylated polymorphonuclear leukocyte-type MMP-8 isoform in Western immunoblotting, but not the 45-55 kDa less glycosylated mesenchymal-type isoform. MMP-8 activation was in practice present only in the OcR samples, and was inhibited by oral doxycycline.

CONCLUSIONS

MMP-8 concentration and activation degree in tear fluid are increased in OcR, probably reflecting increased inflammatory activity. Doxycycline effectively reduces these pathologically excessive levels and activation of MMP-8, and relieves patients' subjective symptoms.

Matrix metalloproteinases: contribution to pathogenesis, diagnosis and treatment of periodontal inflammation

Matrix metalloproteinases (MMPs) form a family of enzymes that mediate multiple functions both in the tissue destruction and immune responses related to periodontal inflammation. The expression and activity of MMPs in non-inflamed periodontium is low but is drastically enhanced to pathologically elevated levels due to the dental plaque and infection-induced periodontal inflammation. Soft and hard tissue destruction during periodontitis and peri-implantitis are thought to reflect a cascade of events involving bacterial virulence factors/enzymes, pro-inflammatory cytokines, reactive oxygen species and MMPs. However, recent studies suggest that MMPs can also exert anti-inflammatory effects in defence of the host by processing anti-inflammatory cytokines and chemokines, as well as by regulating apoptotic and immune responses. MMP-inhibitor (MMPI)-drugs, such as doxycycline, can be used as adjunctive medication to augment both the scaling and root planing-treatment of periodontitis locally and to reduce inflammation systematically. Furthermore, MMPs present in oral fluids (gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), mouth-rinses and saliva) can be utilized to develop new non-invasive, chair/bed-side, point-of-care diagnostics for periodontitis and dental peri-implantitis.

The IGF-I/IGFBP-3 system in gingival crevicular fluid and dependence on application of fixed force

BACKGROUND

During application of orthodontic force on the tooth, various molecular parameters associated with tissue remodeling are changed. IGF-I is a regulatory protein produced during periodontal regeneration. IGF binding proteins-3 (IGFBP-3), a specific IGF-I binding protein, is the major regulatory factor of IGF-I activity.

OBJECTIVES

We tested the hypothesis that changes in the IGF-I/ IGFBP-3 system occur during fixed force application to the tooth and that these changes are detectable in the gingival crevicular fluid (GCF).

METHODS

IGFBP-3 and IGF-I secretion into gingival crevicular fluid (GCF) was analyzed by Western blotting and immunoradiometric assay (IRMA), respectively, in GCF of 6 healthy subjects just prior to and during orthodontics treatment using fixed appliances.

RESULTS

We observed a significant time-dependent decrease of IGFBP-3 content in GCF during orthodontic treatment (4 h and 10 days). Reduction in levels of intact, glycosylated 47 kDa form of IGFBP-3 was associated with its degradation and the appearance of intermediate breakdown products. IGF-I levels were significantly increased 4 h after application of orthodontic force, while they were significantly reduced 10 days after the start of treatment.

CONCLUSIONS

IGFBP-3 secretion into GCF and its molecular structure are modified by the fixed force of orthodontic treatment. Alterations in IGFBP-3 appear to be unrelated to the binding to IGF-I, suggesting an IGF-independent role of this binding protein in tooth movement.

A randomized, double-blind, placebo-controlled trial of the combined effect of doxycycline hyclate 20-mg tablets and metronidazole 0.75% topical lotion in the treatment of rosacea

BACKGROUND

Subantimicrobial doses of doxycycline may improve outcomes in rosacea when combined with topical metronidazole and used as maintenance monotherapy.

OBJECTIVE

The purpose of this study was to evaluate the safety and efficacy of doxycycline hyclate 20 mg (subantimicrobial dose doxycycline) administered twice daily as an adjunct to metronidazole 0.75% topical lotion in the treatment of rosacea.

METHODS

Patients received subantimicrobial doses of doxycycline twice daily plus metronidazole (n = 20) or placebo plus metronidazole (n = 20) for 12 weeks. Subantimicrobial-dose doxycycline or placebo monotherapy continued for 4 weeks. The primary efficacy measure was change from baseline in total inflammatory lesions at weeks 2 and 16.

RESULTS

Total inflammatory lesions were reduced significantly (P =.048) by week 4 and by all subsequent visits in the subantimicrobial-dose doxycycline/metronidazole group compared with placebo/metronidazole. Changes from baseline increased over time and were maintained during subantimicrobial-dose doxycycline monotherapy.

CONCLUSION

Adjunctive use of subantimicrobial dose doxycycline significantly reduced the clinical signs of rosacea compared with metronidazole alone and may be useful maintenance monotherapy.

Generation of biologically active endostatin fragments from human collagen XVIII by distinct matrix metalloproteases

Endostatin, a potent inhibitor of endothelial cell proliferation, migration, angiogenesis and tumor growth, is proteolytically cleaved from the C-terminal noncollagenous NC1 domain of type XVIII collagen. We investigated the endostatin formation from human collagen XVIII by several MMPs in vitro. The generation of endostatin fragments differing in molecular size (24-30 kDa) and in N-terminal sequences was identified in the cases of MMP-3, -7, -9, -13 and -20. The cleavage sites were located in the protease-sensitive hinge region between the trimerization and endostatin domains of NC1. MMP-1, -2, -8 and -12 did not show any significant activity against the C-terminus of collagen XVIII. The anti-proliferative effect of the 20-kDa endostatin, three longer endostatin-containing fragments generated in vitro by distinct MMPs and the entire NC1 domain, on bFGF-stimulated human umbilical vein endothelial cells was established. The anti-migratory potential of some of these fragments was also studied. In addition, production of endostatin fragments between 24-30 kDa by human hepatoblastoma cells was shown to be due to MMP action on type XVIII collagen. Our results indicate that certain, especially cancer-related, MMP family members can generate biologically active endostatin-containing polypeptides from collagen XVIII and thus, by releasing endostatin fragments, may participate in the inhibition of endothelial cell proliferation, migration and angiogenesis.

Matrix metalloproteinases and their tissue inhibitors in aqueous humor of patients with primary open-angle glaucoma, exfoliation syndrome, and exfoliation glaucoma

PURPOSE

To study extracellular matrix (ECM) metabolism by matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in aqueous humor (AH) samples collected from primary open-angle glaucoma (POAG), exfoliation syndrome (EXS), and exfoliation glaucoma (EXG) in relation to samples derived from cataract control patients.

MATERIALS AND METHODS

Seventy-one AH samples were collected during cataract extraction and trabeculectomy. The expression and molecular forms of MMP-2, -8, -9, -13, and -14 and tissue inhibitor of metalloproteinases-1 and -2 (TIMPs) were analyzed by Western immunoblotting. Gelatinase and collagenase activities were studied by zymography and type I collagen degradation assays, respectively. MMP-2 and TIMP-2 concentrations were measured by ELISA assays.

RESULTS

By Western immunoblotting all the studied MMPs were mainly in their latent form in all diagnostic groups. Zymography demonstrated that MMP-2 represents the major gelatinase in AH. Similarly, type I collagenolytic activity was low and similar in cataract and glaucoma samples. In ELISA measurements the TIMP-2 levels were significantly elevated in glaucoma and EXS samples in comparison to cataract controls (P < 0.05).

CONCLUSION

TIMP-2 is elevated in glaucomatous process over MMP-2, which support and further extend the conjuncture that the ECM accumulation rather than degradation predominates in the pathogenesis of POAG and EXG.

Doxycycline may reduce the incidence of aneurysms in haemodialysis vascular accesses

BACKGROUND

Doxycycline can prevent aortic aneurysms through the inhibition of enzymes that degrade vessel walls. We investigated whether haemodialysis patients who had received one or more courses of doxycycline were at less risk for aneurysms in their vascular accesses than those who had received other antibiotics.

METHODS

Three hundred and eight patients undergoing chronic maintenance hemodialysis were evaluated for aneurysm formation after exposure to doxycycline or another antibiotic. Conditional forward logistical analysis using Cox proportional hazards test (SPSS) was performed to determine the potential significance of differences of aneurysm formation between the two groups.

RESULTS

Patients who had received doxycycline appeared to be at lower risk than the control group, but the effect was most obvious in those patients with synthetic grafts.

CONCLUSIONS

Doxycycline may have the ability to reduce aneurysm formation in haemodialysis vascular accesses and a large prospective study is warranted.

Hyperoxia decreases matrix metalloproteinase-9 and increases tissue inhibitor of matrix metalloproteinase-1 protein in the newborn rat lung: association with arrested alveolarization

Matrix metalloproteinases (MMP) are likely effectors of normal lung development, especially branching morphogenesis, angiogenesis, and extracellular matrix degradation. Because hyperoxia exposure (>95% O(2)) from d 4 to 14 in newborn rat pups leads to arrest of alveolarization and mimics newborn chronic lung disease, we tested whether hyperoxia altered MMP-2 and -9 mRNA, protein, and enzymatic activity, and the mRNA and protein expression of the endogenous tissue inhibitor of MMP, TIMP-1. No changes due to hyperoxia exposure were observed in MMP-2 mRNA or pro-enzyme (72 kD) protein levels between d 6 and 14, although the overall protein mass and zymographic activity of the active (68 kD) enzyme were diminished (p < 0.05, ANOVA). However, hyperoxia significantly decreased levels of MMP-9 mRNA and pro-MMP-9 protein and diminished overall MMP-9 pro-enzyme activity. TIMP-1 mRNA was not elevated by hyperoxia until d 14, but protein levels were significantly (p < 0.001) elevated by hyperoxia from d 9 to 14. To estimate the potential of MMP inhibition to arrest alveolarization, administration of doxycycline (20 mg/kg, twice daily by gavage), a pan-MMP proteolysis inhibitor, arrested lung alveolarization. We conclude that hyperoxia decreases MMP-9 mRNA, protein, and activity and elevates TIMP-1 protein, and these changes have the potential to contribute to the arrest of normal lung development.

Continuous periaortic infusion improves doxycycline efficacy in experimental aortic aneurysms

OBJECTIVE

We created a novel continuous infusion system to evaluate the efficacy of juxta-aortic doxycycline delivery as a transitional step toward developing hybrid drug/device treatment strategies for abdominal aortic aneurysm (AAA) disease.

METHODS

Controlled comparison of treatment outcomes was studied in animal models with molecular and morphologic tissue analysis in a collaboration between university and corporate research laboratories. Rat AAAs were created via porcine pancreatic elastase (PPE) infusion and grouped and analyzed by subsequent treatment status (either doxycycline in vehicle or vehicle alone) and drug delivery method (continuous infusion via periaortic delivery system [PDS] or twice-daily subcutaneous injection). The main outcome measures were AAA diameter via direct measurement, medial elastin lamellar preservation via light microscopy, mural smooth muscle cell (SMC) proliferation and SMC and macrophage density via immunostaining and counting, expression of matrix metalloproteinases 2, 9, and 14 and tissue inhibitors of metalloproteinases 1 and 2 via real-time reverse transcriptase-polymerase chain reaction, and enzymatic activity via substrate zymography. Serum drug levels were analyzed via liquid chromatography/mass spectroscopy.

RESULTS

PDS (1.5 mg/kg/day) and subcutaneous (60 mg/kg/day) delivery methods caused comparable reductions in AAA diameter during the period of 14 days after PPE infusion. PDS rats gained more weight during the postoperative period (P <.001), possibly as a result of reduced serum drug levels and systemic toxicity. Doxycycline treatment reduced AAA macrophage infiltration and SMC proliferation significantly. Despite reduced diameter, circumferential elastic lamellar preservation was not apparent in doxycycline-treated AAAs.

CONCLUSIONS

Continuous periaortic infusion lowers the effective doxycycline dose for experimental AAA limitation. Alternative biologic inhibition strategies might also be amenable to direct intra-aortic or juxta-aortic delivery. Periaortic infusion might improve the clinical outcome of minimally invasive AAA treatment strategies. Clinical relevance Aneurysm remodeling may continue after successful endovascular AAA exclusion. Continued proteolytic activity within the aneurysm wall potentiates late graft migration and failure. The doxycycline infusion system developed in these experiments may serve as a prototype for adjuvant treatment modalities that complement endovascular AAA exclusion. Local delivery of doxycycline or other agents active in AAA disease, either continuously or at selected intervals after graft implantation, may stabilize the wall and aid in maintaining aneurysm exclusion. Alternative delivery methods could include passive diffusion from either the graft material itself or treatment reservoirs incorporated into endografts. Given the recognized limitations of current technologies, adjuvant biologic therapies have the potential to improve long-term patient outcome significantly after endovascular exclusion.