Reduced Collagen Degradation Research Articles

Downregulation of microRNA-9 increases matrix metalloproteinase-13 expression levels and facilitates osteoarthritis onset.

Matrix metalloproteinase-13 (MMP-13) degrades collagen and other matrix components, thus playing a critical role in the development of osteoarthritis (OA). The expression level of microRNA-9 (miR-9) is significantly depressed in cartilage tissues of OA patients. Furthermore, bioinformatics analysis demonstrated complementary binding sites between miR-9 and MMP-13. The current study, therefore, investigated whether miR-9 is involved in regulating MMP-13 expression levels and OA onset. Cartilage tissues from OA patients and healthy individuals were compared for miR-9, MMP-13 and collagen type II α1 chain (Col2A1) expression levels. A dual luciferase gene reporter assay was performed to evaluate the association between miR-9 and MMP-13. Sodium iodoacetate was injected into the knee joint cartilage tissues to generate the rat OA model. The expression levels of miR-9, MMP-13 and Col2A1 were compared between the model and control rats. In addition, the OA model rats received miR-9 agomir for further expressional assay. Cartilage tissue samples from the OA patients exhibited significantly lower miR-9 and Col2A1 expression levels when compared with the control rats, whilst the expression level of MMP-13 was upregulated. As the target gene of miR-9, MMP-13 is under the targeted regulation of miR-9. The injection of miR-9 agomir into the knee joint cavity significantly depressed MMP-13 expression in the cartilage tissues of OA rats, with reduced collagen degradation and enhanced COL2A1. OA cartilage tissues have lower miR-9 expression and higher MMP-13 expression levels. Thus, miR-9 inhibits the expression level of MMP-13, decreases its inhibitory effects on COL2A1, and therefore contributes to antagonizing OA.

Serum prolidase activity in systemic sclerosis.

Systemic sclerosis, also known as scleroderma, is a complex systemic inflammatory autoimmune disease that targets the vasculature and connective tissue-producing cells and components of the innate and adaptive immune systems. The disease is characterized by a hardening of the skin and an increased synthesis of collagen . Prolidase is a specific imidodipeptidase involved in collagen degradation. The aim of this study was to search the serum prolidase activity (SPA) in the two subtypes of systemic sclerosis: diffuse and limited cutaneous systemic sclerosis. For this purpose, 35 patients diagnosed with systemic sclerosis (24 diffuse and 11 limited) and 41 healthy control subjects were included in the study. SPA was determined using Myara's method, which is a modification of Chinard's method. SPA did not differ between the scleroderma patients and controls (p=0.467). However, SPA was significantly lower in diffuse form than in both limited form and control subjects (p=0.021 and p=0.024, respectively). SPA also did not differ between the limited form and control subjects (p=0.145). Scleroderma is characterized by excessive deposition of collagen and tissue fibrosis due to the reduced collagen degradation. SPA is reduced in scleroderma patients, especially in diffuse form. Circulating autoantibodies, oxidative stress, and decreased physical activity may contribute to this process.

Synergistic effects of proanthocyanidin, tri-calcium phosphate and fluoride on artificial root caries and dentine collagen

BackgroundProanthocyanidin has been shown to enhance dentine collagen stability and remineralization of artificial root caries. ObjectivesTo evaluate the effect of proanthocyanidin (PA) in combination with tri-calcium phosphate (TCP) and fluoride (F) on resistance to collagen degradation and remineralization of artificial caries lesions. MethodsDemineralized root fragments (n=75) were randomly divided into five groups based on treatments: (i) 6.5% PA, (ii) TCP+F, (iii) TCP+F+6.5% PA, (iv) 1000ppm fluoride (Positive control) and (v) deionized water (control). Each specimen was subjected to pH cycling at 37o C for 8days. Lesion depth and mineral loss were evaluated using microradiography and confocal laser scanning microscopy. The type of crystal formation was determined by XRD spectra. To evaluate the stability of root caries lesions against collagenase challenge, highly purified type VII collagenase from Clostridium was added to obtain a remineralizing solution that contained 7.5U/mL collagenase and pH cycling was repeated. The different remineralizing solutions were collected after the pH cycling to assess the amount of hydroxyproline release. Collagen degradation depth and lesion depth were evaluated using transverse microradiography. Resistance to collagen degradation was determined using hydroxyproline assay. Data were analyzed using one-way ANOVA and Tukey multiple comparison tests. ResultsResults of one-way ANOVA showed that the test solutions had a significant effect on mineral loss (p<0.001) and lesion depth (p<0.001) of artificial root caries. The lowest lesion depth and mineral loss were observed in the TCP+F+PA (p<0.05) group. The XRD patterns showed hydroxyapatite formation on TCP+F-treated artificial caries lesions, which were not altered by the addition of PA. The addition of PA to TCP+F significantly reduced collagen degradation depth, when compared to TCP only group (p<0.001). Lesion depth was the lowest in the PA and TCP+F+PA groups following collagenase degradation (p<0.001). The addition of PA to TCP+F also decreased hydroxyproline release, when compared to TCP+F group (p<0.001). ConclusionThe addition of PA to TCP+F reduced collagen degradation, inhibited demineralization and enhanced remineralization.

Abstract 11400: Targeting Coagulation Factor Xa With Rivaroxaban Reduces the Onset and Progression of Atherosclerosis and Enhances Plaque Stability in ApoE Null Mice

Objective: Atherosclerosis is a progressive chronic inflammatory vascular disease, complicated by plaque rupture and subsequent thrombus formation. In vitro studies indicate that coagulation proteases such as thrombin and factor Xa (FXa) may contribute to pro-atherosclerotic mechanisms mediated through activation of protease-activated receptors (PARs). Whereas experimental thrombin inhibition reduced development and progression of atherosclerosis, the contribution of FXa to atherogenesis has not been elucidated. To assess the involvement of FXa in atherosclerosis, we investigated the effects of direct FXa inhibition by rivaroxaban on experimental atherosclerosis. Approach and Results: Female ApoE -/- mice (age 8-9weeks) received high-fat diet (HFD) or HFD supplemented with rivaroxaban for 8 or 14 weeks (n=10/group). In the second arm, ApoE -/- mice received HFD for 14 weeks, followed by either continuation with HFD or switched to HFD supplemented with rivaroxaban for 6 weeks (n=10/group). Inhibition of FXa decreased the onset of atherosclerosis in the aortic arch after 8 weeks (-36.92%, p&lt;0.05) and 14 weeks (-46.47%, p&lt;0.05) as well as in the carotid artery; 8 weeks (-38.14%, p&lt;0.05) and 14 weeks (-23.38%, p&lt;0.05). Furthermore, progression of pre-existing plaque after 14 weeks was reduced in the aortic arch (-20.85%, p&lt;0.05) and carotid artery (-30.26%, p&lt;0.05). Immunohistochemical staining revealed reduced plaque vulnerability, as reflected by diminished macrophage infiltration (-38.28%, p&lt;0.05), enhanced collagen (+45.30%, p&lt;0.05) and reduced necrotic core (-37.49%, p&lt;0.05). These findings were associated with elevated collagen-producing vascular smooth muscle cells and reduced collagen degradation proteins MMPs. The qualitative and quantitative improvements were accompanied by reduced expression of PARs and their activators, thrombin and FXa. Conclusions: Pharmacological inhibition of FXa with rivaroxaban impedes the onset and progression of atherosclerosis and increased plaque stability, which is possibly mediated through reduced activation of PARs. These data suggest that direct targeting of FXa may be beneficial in treatment of atherosclerosis; to demonstrate clinical relevance further studies are required.

The Effect of Vibration Therapy on Reduction of Matrix Metalloproteinase-9 in Diabetic Ulcer

One important reason why diabetic ulcer fails to heal is an increase of collagen degradation by matrix metalloproteinase-9 (MMP-9). Vibration therapy is one of complementary therapies which can reduce inflammation and improve reepithelialization. However, up to present, there is no study that investigate the effect of vibration on reduction of MMP-9 in diabetic ulcer. Therefore, the effect of vibration on reduction of collagen degradation in diabetic ulcer is still unknown. If vibration can reduce collagen degradation in diabetic ulcer, nurse can recommend patients to apply vibration not only during inflammation and proliferation phase, but also during maturation phase since MMP-9 also contributes to collagen degradation during maturation phase.The purpose of this study was to investigate the effect of vibration on reduction of MMP-9 in diabetic ulcer. Diabetic rats were divided into two groups, vibration and control groups. The intensity of polymorphonuclears cells (PMNs) and fibroblast, collagen appearance, and the presence of positive cells for MMP-9 were compared. Fibroblast, PMNs and collagen appearance were stained with H and E staining, and MMP-9 was stained by immunohistochemistry method. The difference in the intensity of fibroblast and PMNs was analyzed by Mann-Whitney U test. The result showed that the intensity of PMNs was significantly lower, and the intensity of fibroblast was higher in vibration group than in control. Collagen alignment in the vibration group was more organized in a more regular fashion than in control group. The intensity of positive cells for MMP-9 was lower in the vibration group than in control group. This study showed that vibration could reduce MMP-9, therefore it could be concluded that vibration could reduce collagen degradation of diabetic ulcer. This study bring implication in the clinical setting that vibration therapy should also be applied during maturation phase since MMP-9 is also released in the maturation phase.

Antibacterial properties of copper iodide-doped glass ionomer-based materials and effect of copper iodide nanoparticles on collagen degradation.

This study investigated the antibacterial properties and micro-hardness of polyacrylic acid (PAA)-coated copper iodide (CuI) nanoparticles incorporated into glass ionomer-based materials, and the effect of PAA-CuI on collagen degradation. PAA-CuI nanoparticles were incorporated into glass ionomer (GI), Ionofil Molar AC, and resin-modified glass ionomer (RMGI), Vitrebond, at 0.263wt%. The antibacterial properties against Streptococcus mutans (n=6/group) and surface micro-hardness (n=5/group) were evaluated. Twenty dentin beams were completely demineralized in 10wt% phosphoric acid and equally divided in two groups (n=10/group) for incubation in simulated body fluid (SBF) or SBF containing 1mg/ml PAA-CuI. The amount of dry mass loss and hydroxyproline (HYP) released were quantified. Kruskal-Wallis, Student's t test, two-way ANOVA, and Mann-Whitney were used to analyze the antibacterial, micro-hardness, dry mass, and HYP release data, respectively (p<0.05). Addition of PAA-CuI nanoparticles into the glass ionomer matrix yielded significant reduction (99.999%) in the concentration of bacteria relative to the control groups. While micro-hardness values of PAA-CuI-doped GI were no different from its control, PAA-CuI-doped RMGI demonstrated significantly higher values than its control. A significant decrease in dry mass weight was shown only for the control beams (10.53%, p=0.04). Significantly less HYP was released from beams incubated in PAA-CuI relative to the control beams (p<0.001). PAA-CuI nanoparticles are an effective additive to glass ionomer-based materials as they greatly enhance their antibacterial properties and reduce collagen degradation without an adverse effect on their mechanical properties. The use of copper-doped glass ionomer-based materials under composite restorations may contribute to an increased longevity of adhesive restorations, because of their enhanced antibacterial properties and reduced collagen degradation.

Oral submucous fibrosis associated with malignancy

Oral submucous fibrosis (OSF) is a chronic condition of the oral mucosa, first described among five East African women of Indian origin under the term atrophia idiopathica (tropica) mucosae oris. It is characterized by a generalized submucous fibrosis. The pathogenesis of the disease is not well-established, but epidemiological evidences strongly indicate the association of betel quid habit. It is logical to hypothesize that the increased collagen production or reduced collagen degradation is the possible mechanism in the development of the disease. The malignant potentiality and also the origin of cancers in different intraoral locations in OSF patients is attributable to the generalized epithelial atrophy. Here, a clinical case of OSF in a 36-year-old male patient is being discussed, encompassing the pathogenesis and malignant potentiality of the disease.

MMPs activity and bond strength in deciduous dentine–resin bonded interfaces

ObjectivesTo determine effect of ageing on deciduous dentine–resin interfaces bond strength and the metalloproteinases (MMPs) activity at the hybrid layer compared to permanent dentine. MethodsMicrotensile bond strength (MTBS) tests were performed in human deciduous and permanent dentine after 24h, 3 and 6 months using an etch and rinse adhesive. C-terminal telopeptide concentrations (ICTP) were calculated, in order to determine MMPs mediated collagen degradation at the hybrid layer. ResultsThe highest MMPs-mediated collagen degradation values occurred in phosphoric acid demineralized dentine, ICTP values were similar for deciduous and permanent dentine after 1 week. Resin infiltration decreased collagen degradation in both dentins and ICTP values were similar to those attained by for untreated dentine. In resin infiltrated and untreated dentine specimens collagen degradation was always higher for deciduous dentine. At 24h, MTBS was higher in permanent dentine. After ageing MTBS decreased and performed similarly in both dentins. ConclusionsHigher collagenollytic activity is found in deciduous than in permanent dentine. At 24h, collagen cleavage by MMPs at the hybrid layer is higher in deciduous dentine leading to a lower MTBS. Clinical significanceThe presence of resin monomers reduced collagen degradation when applied on demineralized dentine, but exerted protection was lower in deciduous dentine.

A ZnO-doped adhesive reduced collagen degradation favouring dentine remineralization

ObjectivesThe objective of the study was to determine the efficacy of a ZnO-doped etch and rinse adhesive in decreasing MMPs-mediated collagen degradation at the resin–dentine hybrid layer, and increasing bonding stability. MethodsC-terminal telopeptide concentrations (ICTP) were determined after 24h, 1wk and 4wk in human dentine beams. Dentine was treated: (1) 37% phosphoric acid for 15s (PA), (2) PA-etched dentine infiltrated with Single Bond (SB), (3) PA-etched dentine infiltrated with ZnO doped SB (ZnO particles – 10wt% – were added to the bonding resin) (ZnO–SB), and (4) Clearfil SE Bond primed-dentine was infiltrated with Clearfil SE bonding resin (CSE). Microtensile bond strength (MTBS) was assessed for the different groups at 24h and after 3months. Debonded dentine surfaces were studied by scanning electron microscopy. ResultsMMPs-mediated collagen degradation occurred in demineralized dentine (PA). Resin infiltration decreased collagen degradation. The lowest collagen degradation was found for Zn-doped SB, followed by CSE. When these adhesives were applied, ICTP values did not change throughout the study period. At 24h, similar MTBS was attained for all adhesives. Only SB decreased MTBS after three months. ConclusionsAddition of ZnO particles to SB produced a reduction in dentine collagen degradation and increased resin–dentine bonds durability. In Zn-doped adhesive interfaces, a calcium phosphate layer and tubular occlusion was encountered at the debonded interface. Clinical significanceZnO particles addition into the bonding resin of SB makes a breakthrough to prevent the hybrid layer degradation and to preserve its bonding efficacy overtime.

Zinc-Inhibited MMP-Mediated Collagen Degradation after Different Dentine Demineralization Procedures

Background: Dentine matrix metalloproteinases (MMPs) play an important role in the dentine caries process. Aims: To determine if MMP-mediated collagen degradation of acid-demineralized dentine may be inhibited by zinc or zinc chelators. Methods: Human dentine specimens were demineralized by phosphoric acid (PA), ethylenediaminetetraacetic acid (EDTA), Clearfil SE Bond primer (SE), or Xeno V (XE) and stored in artificial saliva. Chlorhexidine digluconate (CHX), doxycycline, EDTA, or ZnCl₂ was added. C-terminal telopeptide determinations (ICTP) were performed by radioimmunoassay after 24 h and 4 weeks. Results: Collagen degradation was prominent in PA-demineralized (ICTP values from 74.01 µg/l at 24 h to 202.46 µg/l after 4 weeks) and EDTA-demineralized dentine (ICTP values from 83.93 µg/l at 24 h to 158.82 µg/l after 4 weeks) stored in artificial saliva. Doxycycline fully blocked proteolysis. CHX and EDTA reduced collagen degradation only at 24 h. Zinc in excess strongly inhibited hydrolysis of collagen in all tested groups (ICTP values were: PA, 13.56 µg/l; EDTA, 11.21 µg/l; SE, 1.52 µg/l, and XE, 2.37 µg/l) and its effect was maintained for up to 4 weeks, except for EDTA-treated dentine (ICTP values were: PA, 40.76 µg/l; EDTA, 79.15 µg/l; SE, 5.29 µg/l, and XE, 6.38 µg/l). Conclusion: EDTA and CHX exerted time-limited MMP inhibition, and excess zinc served as an effective inhibitor of MMP-mediated collagen degradation in strong or mildly demineralized dentine. MMP degradation of collagen was reduced in resin-infiltrated dentine; the presence of excess zinc chloride exerted an additional protective effect.

Nitric Oxide Releasing Nanoparticles for Treatment of Candida Albicans Burn Infections

Candida albicans is a leading fungal cause of burn infections in hospital settings, and sepsis is one of the principle causes of death after a severe burn. The prevalence of invasive candidiasis in burn cases varies widely, but it accounts for 3–23% of severe infection with a mortality rate ranging from 14 to 70%. Therefore, it is imperative that we develop innovative therapeutics to which this fungus is unlikely to evolve resistance, thus curtailing the associated morbidity and mortality and ultimately improving our capacity to treat these infections. An inexpensive and stable nitric oxide (NO)-releasing nanoparticle (NO-np) platform has been recently developed. NO is known to have direct antifungal activity, modulate host immune responses and significantly regulate wound healing. In this study, we hypothesized that NO-np would be an effective therapy in the treatment of C. albicans burn infections. Using a murine burn model, NO-np demonstrated antifungal activity against C. albicans in vivo, most likely by arresting its growth and morphogenesis as demonstrated in vitro. NO-np demonstrated effective antimicrobial activity against yeast and filamentous forms of the fungus. Moreover, we showed that NO-np significantly accelerated the rate of wound healing in cutaneous burn infections when compared to controls. The histological evaluation of the affected tissue revealed that NO-np treatment modified leukocyte infiltration, minimized the fungal burden, and reduced collagen degradation, thus providing potential mechanisms for the therapeutics’ biological activity. Together, these data suggest that NO-np have the potential to serve as a novel topical antifungal which can be used for the treatment of cutaneous burn infections and wounds.

Contribution of circulating biomarkers to unravel the role of extracellular matrix in hypertensive cardiac remodelling

Contribution of circulating biomarkers to unravel the role of extracellular matrix in hypertensive cardiac remodelling

Pathogenesis of oral submucous fibrosis

Data from recent epidemiological studies provide overwhelming evidence that areca nut is the main etiological factor for oral submucous fibrosis (OSF). It is logical to hypothesize that the increased collagen synthesis or reduced collagen degradation is the possible mechanism in the development of the disease. There are numerous biological pathways involved in the above processes and it is likely that the normal regulatory mechanisms are either down regulated or up regulated at different stages of the disease. The copper content of areca nut is high and the possible role of copper as a mediator of fibrosis is supported by the demonstration of the up regulation of lysyl oxidase in OSMF biopsies. The aim of this article is to emphasize that the incorporation of copper into the areca nut is through the Bordeaux mixture, which is sprayed as a fungicide on areca plantations in regions with scheduled monsoons and of which copper sulfate is an important constituent.

Zinc-doped dentin adhesive for collagen protection at the hybrid layer

The aim of the study was to ascertain whether the addition of zinc to adhesives may decrease metalloproteinase-mediated collagen degradation without affecting bonding efficacy. Human dentin beams were treated with phosphoric acid, with Clearfil SE Bond Primer or with Clearfil SE Bond Primer plus ZnCl(2) (2 wt%). Acid-etched dentin was infiltrated with Single Bond, Single Bond plus ZnCl(2) (2 wt%), or Single Bond plus ZnO nanoparticles (10 wt%), and Clearfil SE Bond-primed dentin was infiltrated with Clearfil SE Bonding resin, Clearfil SE-Bonding resin with ZnCl(2) (2 wt%), or Clearfil SE-Bonding resin with ZnO nanoparticles (10 wt%). The C-terminal telopeptide concentrations were determined 24 h, and 1 and 4 wk after treatment. Microtensile bond strength to dentin was determined for the tested adhesives. Matrix metalloproteinases-mediated collagen degradation occurred in acid-etched and SE-primed dentin. Resin infiltration decreased collagen degradation. Lower collagen degradation was found for SE Bond than for Single Bond. Zinc-doped Single Bond resin always reduced collagen degradation, the ZnO particles being more effective than ZnCl(2) . Zinc-doped SE Bond reduced the liberation of C-terminal telopeptide only at 24 h. Bond strength to dentin was not decreased when Zn-doped resins were employed, except when ZnCl(2) was added to SE Primer. Zinc-doped resin reduced collagen degradation in Single Bond hybrid layers, but did not affect bond strength. The addition of zinc to SE Bond had no beneficial effects.

Effect of dentin etching and chlorhexidine application on metalloproteinase‐mediated collagen degradation

Dentin matrix metalloproteinases (MMPs) are involved in the degradation of collagen in resin-dentin interfaces. This study evaluated whether collagen degradation can be prevented by chlorhexidine digluconate (CHX) after different dentin demineralization procedures. The demineralization of human dentin was performed with phosphoric acid (PA), EDTA or acidic monomers (Clearfil SE Bond and Xeno V). Specimens were stored (for 24 h, or for 1 or 3 wk) in the presence or absence of CHX. In half of the groups, active MMP-2 was incorporated into the storage solution. At the end of each storage period, the C-terminal telopeptide (ICTP) concentration (which indicates the amount of collagen degradation) was measured in the storage solution. Collagen degradation was higher in PA- and EDTA-demineralized dentin. Chlorhexidine digluconate reduced collagen degradation in these groups only for 24 h. When dentin was demineralized with Clearfil SE Bond or Xeno V, collagen degradation was reduced by up to 30%, but the addition of exogenous MMP-2 significantly increased collagen degradation. In self-etchant-treated dentin, the inhibitory effect of CHX on MMPs lasted for up to 3 wk. Treating dentin with EDTA, PA or self-etching agents produces enough demineralization to permit cleavage of the exposed collagen. Monomer infiltration may exert protection on demineralized collagen, probably through immobilization of MMPs. The partial inhibitory action of CHX on MMP activity produced by self-etching adhesives was prolonged compared with the short-acting PA- or EDTA-treated dentin.

Novel selective MMP-13 inhibitors reduce collagen degradation in bovine articular and human osteoarthritis cartilage explants

MMP-13 is highly upregulated in arthritis and therefore strongly implicated in the pathogenesis of osteoarthritis (OA). Selective inhibition of MMP-13 may provide the desired cartilage degradation protection, while overcoming the musculoskeletal toxicity seen with nonselective inhibition of MMPs. Activity and selectivity of novel MMP-13 inhibitors were determined in enzymatic and collagenase assays. Inhibition kinetics and competitive binding experiments were performed. The inhibition of collagen degradation was studied in cartilage explants from OA patients and in bovine and human articular cartilage systems. We have identified a new class of very potent and highly selective non-zinc-binding MMP-13 inhibitors. Selective MMP-13 inhibitors completely blocked type II collagen degradation in bovine explants and showed up to 80% inhibition in human OA cartilage. These results indicate MMP-13 as the primary collagenase in the human OA cartilage and in the IL-1/OSM-induced cartilage degradation process and suggest that selective MMP-13 inhibitors may be a potential treatment of OA.

Oral Submucous Fibrosis: Review on Etiopathogenesis

Summary data from recent epidemiological studies provide overwhelming evidence that areca nut is the main aetiological factor for OSF. Commercially freeze dried products such as pan masala, Guthka and mawa have high concentrates of areca nut per chew and appear to cause OSF more rapidly than by self prepared conventional betel quid that contain smaller amounts of areca nut. It is logical to hypothesize that the increased collagen synthesis or reduced collagen degradation as possible mechanisms in the development of the disease. These chemicals appear to interfere with the molecular processes of deposition and/or degradation of extracellular matrix molecules such as collagen. In vitro studies on human fibroblasts using areca extracts or chemically purified arecoline support the theory of fibroblastic proliferation and increased collagen formation that is also demonstrable histologically in human OSF tissues. The copper content of areca nut is high and the possible role of copper as a mediator of fibrosis is supported by the demonstration of up regulation of lysyl oxidase in OSF biopsies. It has been postulated that areca nut may also induce the development of the disease by increased levels of cytokines in the lamina propria. Current evidence implicates collagen-related genes in the susceptibility and pathogenesis of OSF. The individual mechanisms operating at various stages of the disease– initial, intermediate and advanced–need further study in order to propose appropriate therapeutic interventions.

Pellegrini–Stieda Disease in Traumatic Brain Injury Rehabilitation

Pellegrini–Stieda disease (PSD) is posttraumatic ossification of the proximal attachment of the medial collateral ligament of the knee, diagnosed by radiography.1 Antecedent traumas include direct and indirect injury to the medial side of the knee. Repeated microtraumas, including therapeutic manipulation of a stiff joint and postsurgical rehabilitation, have also been reported.2 Because PSD is rarely diagnosed in neurologic rehabilitation patients, only one case of spinal cord injury having this disease was reported.3 We describe a traumatic brain injury patient with clinical and radiologic findings of PSD. Our aim in this report is to show that this entity can be seen in neurological rehabilitation patients during the course of exercise treatment and must be taken into account in differential diagnosis of knee pain, swelling, and range-of-motion limitation. A 22-yr-old man, with contusion lesions determined by cranial computerized tomography secondary to a motorcycle accident, attended our clinic for rehabilitation. The patient had a history of 3 mos of hospitalization in the intensive care unit and anesthesia clinic in another hospital for multiple traumas. The patient did not describe any known injury or trauma to the knee in the motorcycle accident. On examination, the patient was found to have range-of-motion limitation with swelling and complaint of pain in his left knee. The patient had no history of systemic diseases such as gout, rheumatoid arthritis, systemic sclerosis, sarcoidosis, or hyperparathyroidism. On physical examination, the left knee was limited at 60 degrees of flexion, extension was at a normal range, and the knee joint was stable. Serum calcium, phosphate, and alkaline phosphatase levels were within normal ranges. The plain radiographs demonstrated a characteristic bony formation, calcification medial to the femoral condyle (Fig. 1). Because of the characteristic radiographic findings and the clinical course, the diagnosis of PSD was considered.FIGURE 1: Anteroposterior radiogram reveals a massive bony tissue (arrows) medial to the femoral condyle.PSD manifests radiographically, with ossification arising from the epicondylar portion of the medial femoral condyle.1 In the etiology of neurogenic ectopic bone formation, humoral, neural, and local factors, including tissue hypoxia, hypercalcemia, changes in sympathetic nerve activity, prolonged immobilization, and mobilization with frequent periods of exercising after prolonged immobilization, play a role. In traumatic brain injury patients, neurogenic heterotopic ossification can result in accelerated fracture healing. Reduced collagen degradation in polytraumas with traumatic brain injury causes enhanced osteogenesis.4 Radiographically, the ossification is seen as a thin crescent or curvilinear line of a few millimeters from the femoral condyle. This feature is crucial for ruling out other lesions including fracture of the femoral condyle, periostitis, and osteoma.1 In conclusion, PSD can be seen in neurologic rehabilitation patients during the course of exercise treatment, and it must be taken into account in the differential diagnosis of knee pain, swelling, and range-of-motion limitation.

Reduced Collagen Degradation in Polytraumas with Traumatic Brain Injury Causes Enhanced Osteogenesis

Patients with traumatic brain injury (TBI) and skeletal injuries have increased rates of excessive bone healing (EH = hypertrophic callus formation and/or heterotopic ossification). Polytrauma patients are often attributed higher rates of delayed fracture union. This study compares 182 total fractures in 29 isolated polytrauma patients (POLY) and 48 patients after TBI and polytrauma (TBI+POLY), examining the clinical parameters of EH versus delay. A subset of 28 patients (13 TBI+POLY, 15 POLY) underwent serological testing for the following bone turnover parameters: carboxy-terminal extension peptide of type 1 procollagen (P1CP), pyridinolene cross-linked carboxy-terminal telopeptide (1CTP), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), and basic fibroblast growth factor (bFGF). There were higher rates of delayed union in the POLY patients (45% vs. 23%) and EH in the TBI+POLY patients (33% vs. 17%) (not significant = NS). More delayed unions were observed in diaphyseal fractures suffered by POLY (28%) than in TBI+POLY (15%) patients (NS). EH after pelvic fracture was apparent in 52% TBI+POLY and in 21% POLY fractures (NS). P1CP levels did not differ between the groups, but the collagen breakdown parameter 1CTP was significantly higher in the POLY group (p = 0.01-0.04). IGF-1 levels were below normal in both groups, and did not differ. IGFBP-3, an IGF-1-inhibiting and collagenase-3-activating protein, was significantly higher in POLY patients (p = 0.017-0.037). bFGF levels did not vary between groups. Increased serum levels of 1CTP and IGFBP-3 in POLY patients suggest that EH in TBI patients is secondary to decreased collagen breakdown rather than increased synthesis.

Preeclampsia-associated reduction of cathepsin D activity in the umbilical cord

Background Preeclampsia is accompanied by an increase of collagen contents in the umbilical cord (UC) arteries and in Wharton's jelly. Cathepsin D is one of the enzymes which participates in collagen degradation and activates precursor forms of collagenolytic metalloproteinases. It was decided to evaluate the activity of cathepsin D within umbilical cord arteries, veins and Wharton's jelly and its alterations in preeclampsia. Materials and methods Umbilical cord components were separated and submitted to homogenisation/extraction with 0.05 M Tris–HCl+0.2% Triton X-100, pH 7.5. Proteolytic activities of the extracts were studied with a use of cathepsin D-specific substrate. Western immunoblot technique was employed to detect this enzyme. Results It was found that human umbilical cord tissues contain both active and inactive forms of cathepsin D. Preeclampsia is associated with a distinct increase in the amount of this enzyme in the umbilical cord, whereas its activity deeply decreased. Activation with trypsin augments cathepsin D activity in preeclamptic umbilical cord to the values observed in control arteries or even exceeds the control values (veins, Wharton's jelly). Conclusions Preeclampsia is associated with a reduction in the activity of cathepsin D in human umbilical cord. The low activity of cathepsin D may reduce collagen degradation and enhance its accumulation in the umbilical cord, especially in the arteries. Similar changes in other foetal blood vessels may result in an increase of vascular resistance and hypertension, which may persist after birth.