Indices of extracellular matrix turnover in human masseter muscles as markers of craniofacial form—a preliminary study. Eur J Orthod

Division of Biomaterials and Tissue Engineering and Orthodontic Unit, UCL Eastman Dental Institute, London, UK.
The European Journal of Orthodontics (Impact Factor: 1.48). 05/2008; 30(2):217-25. DOI: 10.1093/ejo/cjm105
Source: PubMed


Environmental remodelling of the craniofacial musculature is obligatory for successful outcomes following interventions such as functional appliance therapy or orthognathic surgery. Genetically driven remodelling of the craniofacial musculature is also seen in individuals with altered facial form. The processes that are involved in the remodelling of intramuscular connective tissue need to be activated in such situations. Such processes require activity of matrix metalloproteinases (MMPs) and the tissue inhibitors of matrix metalloproteinases (TIMPs), which are responsible for extracellular matrix (ECM) turnover. The aim of this study was, therefore, to establish the expression of MMP-2 and MMP-9 and their inhibitors, TIMP-1 and TIMP-2, in the masseter muscle of humans with both normal and increased vertical facial form and to assess whether this expression had any value as a predictor of facial form. Biopsies were taken from 20 subjects (10 with vertical facial deformity and 10 with normal vertical facial form to act as a control group). The sample group consisted of 15 females and 5 males and the average age of the donors +/- standard deviation (SD) was 26.04 +/- 6.16 years (range: 17.67-31.25 years). Biopsy samples were then subjected to zymography and reverse zymography to assess MMP and TIMP expression, respectively. Lateral skull cephalograms were analysed for each subject using Spearman's rho correlation coefficients and Mann-Whitney U-tests. TIMP-1 activity was consistently expressed in human masseter muscle. MMP-2, MMP-9, and TIMP-2 activity, when detected, was at a low level. These data indicate that in most individuals, an excess of TIMP-1, compared with MMP-2 and MMP-9, limits ECM turnover in human masseter muscle. There was a demonstrable variation in proteinase expression between different individuals. These preliminary findings, however, do not confirm that indices of ECM turnover are a reflection of an individual's vertical facial form.

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Available from: Nigel P Hunt, Feb 14, 2014
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    • "It is also known that the tissue inhibitors metalloproteinases (TIMPs) are synthesized to bind directly to active enzymes to prevent their activity [16]. In human masseter muscle, Tippett et al. [17] found that an excess of tissue inhibitors metalloproteinase (TIMP-1) restricted extracellular matrix turnover and is interrelated with MMP-2 and MMP-9. "
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    ABSTRACT: Although disorders of the stomatognathic system are common, the mechanisms involved are unknown. Our objective was to study the changes in the masseter muscles after unilateral exodontia. Molar extraction was performed on Wistar rats (left side), and the animals were sacrificed after either 14 or 26 days. The masseter muscle was processed for histological analysis, conventional and in situ zymography, and immunohistochemistry. The morphological analysis showed unique and specific characteristics for the experimental group. By conventional zymography no significant values of 72 kDa MMP-2 (P < 0.05) were found in both of the sides of masseter muscle after 14 and 26 days of unilateral extraction. The in situ zymography showed gelatinolytic activity on all deep masseter muscles, with significant increase on the contralateral side after 14 and 26 days (P < 0.05). The immunohistochemistry demonstrated greater expression of MMP-2 than MMP-9 and MMP-14 in all masseter muscles and there were few differences in the staining of 4 TIMPs. This knowledge about morphology and molecular masticatory muscle remodeling following environmental interventions can be used to develop clinically successful treatments.
    BioMed Research International 06/2014; 2014:563463. DOI:10.1155/2014/563463 · 2.71 Impact Factor
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    • "The inherent (genetic) contribution of the CFMAS in the brachycephalic and dolichocephalic individual is believed to influence maxillomandibular rotation [75, 99]. Brachycephalic individuals tend to be europrosopic, strong muscled [100] and display a hypodivergent radiographic profile, while dolichocephalic individuals tend to be leptoprosopic, weak muscled [100] and display a hyperdivergent radiographic profile (see Dale [101] for a detailed comparison). "
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    The Open Dentistry Journal 02/2009; 3(1):100-13. DOI:10.2174/1874210600903010100
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    ABSTRACT: Engineering complex tissues requires a precisely formulated combination of cells, spatiotemporally released bioactive factors, and a specialized scaffold support system. Injectable materials, particularly those delivered in aqueous solution, are considered ideal delivery vehicles for cells and bioactive factors and can also be delivered through minimally invasive methods and fill complex 3D shapes. In this review, we examine injectable materials that form scaffolds or networks capable of both replacing tissue function early after delivery and supporting tissue regeneration over a time period of weeks to months. The use of these materials for tissue engineering within the craniofacial complex is challenging but ideal as many highly specialized and functional tissues reside within a small volume in the craniofacial structures and the need for minimally invasive interventions is desirable due to aesthetic considerations. Current biomaterials and strategies used to treat craniofacial defects are examined, followed by a review of craniofacial tissue engineering, and finally an examination of current technologies used for injectable scaffold development and drug and cell delivery using these materials.
    Advanced Materials 09/2009; 21(32-33):3368-93. DOI:10.1002/adma.200802009 · 17.49 Impact Factor
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