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Vespasiano V, Mulder CS, Klop C, Koolstra JH, Nolte JW, Lobé NHJ, Beenen LFM, Becking AG. Mineralization and thickness of the condylar cortex in skeletal remains of children's mandibles: A preliminary study. Arch Oral Biol 2024; 157:105850. [PMID: 38007946 DOI: 10.1016/j.archoralbio.2023.105850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 11/05/2023] [Accepted: 11/14/2023] [Indexed: 11/28/2023]
Abstract
OBJECTIVE To explore the relationship between the volumetric bone mineral density (vBMD), the thickness of the condylar cortex (Tcortex) and the hemimandibular volumes (Vhemimandible) of symmetrical and asymmetrical mandibles of children. DESIGN The data collection consisted of 92 archeological skeletal remains of children's mandibles between 1 and 12 years old. The mandibles were digitalized with a computed tomography (CT) scan, and three dimensional models were obtained. Vhemimandible was calculated using the optimal symmetry plane. The volumes were used to calculate the asymmetry index (AI). Mandibles with an AI of ≥ 3% (N = 9) and a sample of the most symmetrical mandibles (N = 9) were selected for this research. Three groups were created: a symmetrical, an asymmetrical and a pooled group. Micro-CT was used to measure the vBMD and Tcortex in four volumes of interest. The AI was calculated for these parameters as well. RESULTS Significant correlations were found between the vBMD and the Tcortex in the pooled group (P < .01) and between the AI of the vBMD and the AI of the Tcortex in the pooled (P < .01) and symmetrical group (P < .05). No significant correlations were found between the vBMD and the Vhemimandible and between the respective AIs. Between the Tcortex and the Vhemimandible a significant correlation was found in the pooled and asymmetrical group. CONCLUSION There is a relationship between the vBMD and the Tcortex. The correlations between the Tcortex and the Vhemimandible are insufficient to draw firm conclusions. A relationship between the vBMD and Vhemimandible was not confirmed in this study.
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Affiliation(s)
- V Vespasiano
- Department of Oral and Maxillofacial Surgery, Amsterdam University Medical Centers (location AMC) and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
| | - C S Mulder
- Department of Oral and Maxillofacial Surgery, Amsterdam University Medical Centers (location AMC) and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - C Klop
- Department of Oral and Maxillofacial Surgery, Amsterdam University Medical Centers (location AMC) and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - J H Koolstra
- Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, the Netherlands
| | - J W Nolte
- Department of Oral and Maxillofacial Surgery, Amsterdam University Medical Centers (location AMC) and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - N H J Lobé
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers (location AMC), University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - L F M Beenen
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers (location AMC), University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - A G Becking
- Department of Oral and Maxillofacial Surgery, Amsterdam University Medical Centers (location AMC) and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
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Nerve spectroscopy: understanding peripheral nerve autofluorescence through photodynamics. Surg Endosc 2021; 35:7104-7111. [PMID: 33782757 DOI: 10.1007/s00464-020-08227-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Being able to accurately identify sensory and motor nerves is crucial during surgical procedures to prevent nerve injury. We aimed to (1) evaluate the feasibility of performing peripheral human nerve visualization utilizing nerves' own autofluorescence in an ex-vivo model; (2) compare the effect of three different nerve fiber fixation methods on the intensity of fluorescence, indicated as the intensity ratio; and (3) similarly compare three different excitation ranges. METHODS Samples from various human peripheral nerves were selected postoperatively. Nerve fibers were divided into three groups: Group A nerve fibers were washed with a physiologic solution; Group B nerve fibers were fixated with formaldehyde for 6 h first, and then washed with a physiologic solution; Group C nerve fibers were fixated with formaldehyde for six hours, but not washed afterwards. An Olympus IX83 inverted microscope was used for close-up image evaluation. Nerve fibers were exposed to white-light wavelength spectrums for a specific time frame prior to visualization under three different filters-Filter 1-LF405-B-OMF Semrock; Filter 2-U-MGFP; Filter 3-U-MRFPHQ Olympus, with excitation ranges of 390-440, 460-480, and 535-555, respectively. The fluorescence intensity of all images was subsequently analyzed using Image-J Software, and results compared by analysis of variance (ANOVA). RESULTS The intensity ratios observed with Filter 1 failed to distinguish the different nerve fiber groups (p = 0.39). Conversely, the intensity ratios seen under Filters 2 and 3 varied significantly between the three nerve-fiber groups (p = 0.021, p = 0.030, respectively). The overall intensity of measurements was greater with Filter 1 than Filter 3 (p < 0.05); however, all nerves were well visualized by all filters. CONCLUSION The current results on ex vivo peripheral nerve fiber autofluorescence suggest that peripheral nerve fiber autofluorescence intensity does not greatly depend upon the excitation wavelength or fixation methods used in an ex vivo setting. Implications for future nerve-sparing surgery are discussed.
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Franks EM, Holton NE, Scott JE, McAbee KR, Rink JT, Pax KC, Pasquinelly AC, Scollan JP, Eastman MM, Ravosa MJ. Betwixt and Between: Intracranial Perspective on Zygomatic Arch Plasticity and Function in Mammals. Anat Rec (Hoboken) 2017; 299:1646-1660. [PMID: 27870345 DOI: 10.1002/ar.23477] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 06/04/2016] [Accepted: 06/22/2016] [Indexed: 01/01/2023]
Abstract
The zygomatic arch is morphologically complex, providing a key interface between the viscerocranium and neurocranium. It also serves as an attachment site for masticatory muscles, thereby linking it to the feeding apparatus. Though morphological variation related to differential loading is well known for many craniomandibular elements, the adaptive osteogenic response of the zygomatic arch remains to be investigated. Here, experimental data are presented that address the naturalistic influence of masticatory loading on the postweaning development of the zygoma and other cranial elements. Given the similarity of bone-strain levels among the zygoma and maxillomandibular elements, a rabbit and pig model were used to test the hypothesis that variation in cortical bone formation and biomineralization along the zygomatic arch and masticatory structures are linked to increased stresses. It was also hypothesized that neurocranial structures would be minimally affected by varying loads. Rabbits and pigs were raised for 48 weeks and 8 weeks, respectively. In both experimental models, CT analyses indicated that elevated masticatory loading did not induce differences in cortical bone thickness of the zygomatic arch, though biomineralization was positively affected. Hypotheses were supported regarding bone formation for maxillomandibular and neurocranial elements. Varying osteogenic responses in the arch suggests that skeletal adaptation, and corresponding variation in performance, may reside differentially at one level of bony architecture. Thus, it is possible that phenotypic diversity in the mammalian zygoma is due more singularly to natural selection (vs. plasticity). These findings underscore the complexity of the zygomatic arch and, more generally, determinants of skull form. Anat Rec, 299:1646-1660, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Erin M Franks
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana
| | - Nathan E Holton
- Department of Orthodontics, The University of Iowa, Iowa City, Iowa.,Department of Anthropology, The University of Iowa, Iowa City, Iowa
| | - Jeremiah E Scott
- Department of Anthropology, Southern Illinois University, Carbondale, Illinois
| | - Kevin R McAbee
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana
| | - Jason T Rink
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana
| | - Kazune C Pax
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana
| | - Adam C Pasquinelly
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana
| | - Joseph P Scollan
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana
| | - Meghan M Eastman
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana
| | - Matthew J Ravosa
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, Indiana.,Department of Aerospace and Mechanical Engineering, The University of Notre Dame, Notre Dame, Indiana.,Department of Anthropology, The University of Notre Dame, Notre Dame, Indiana
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4
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Stelzle F, Rohde M, Riemann M, Oetter N, Adler W, Tangermann-Gerk K, Schmidt M, Knipfer C. Autofluorescence spectroscopy for nerve-sparing laser surgery of the head and neck-the influence of laser-tissue interaction. Lasers Med Sci 2017; 32:1289-1300. [PMID: 28551764 DOI: 10.1007/s10103-017-2240-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 05/18/2017] [Indexed: 11/30/2022]
Abstract
The use of remote optical feedback systems represents a promising approach for minimally invasive, nerve-sparing laser surgery. Autofluorescence properties can be exploited for a fast, robust identification of nervous tissue. With regard to the crucial step towards clinical application, the impact of laser ablation on optical properties in the vicinity of structures of the head and neck has not been investigated up to now. We acquired 24,298 autofluorescence spectra from 135 tissue samples (nine ex vivo tissue types from 15 bisected pig heads) both before and after ER:YAG laser ablation. Sensitivities, specificities, and area under curve(AUC) values for each tissue pair as well as the confusion matrix were statistically calculated for pre-ablation and post-ablation autofluorescence spectra using principal component analysis (PCA), quadratic discriminant analysis (QDA), and receiver operating characteristics (ROC). The confusion matrix indicated a highly successful tissue discrimination rate before laser exposure, with an average classification error of 5.2%. The clinically relevant tissue pairs nerve/cancellous bone and nerve/salivary gland yielded an AUC of 100% each. After laser ablation, tissue discrimination was feasible with an average classification accuracy of 92.1% (average classification error 7.9%). The identification of nerve versus cancellous bone and salivary gland performed very well with an AUC of 100 and 99%, respectively. Nerve-sparing laser surgery in the area of the head and neck by means of an autofluorescence-based feedback system is feasible even after ER-YAG laser-tissue interactions. These results represent a crucial step for the development of a clinically applicable feedback tool for laser surgery interventions in the oral and maxillofacial region.
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Affiliation(s)
- Florian Stelzle
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), University Hospital Erlangen, Glückstraße 11, 91054, Erlangen, Germany.,Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 6, 91052, Erlangen, Germany
| | - Maximilian Rohde
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), University Hospital Erlangen, Glückstraße 11, 91054, Erlangen, Germany.,Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 6, 91052, Erlangen, Germany
| | - Max Riemann
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), University Hospital Erlangen, Glückstraße 11, 91054, Erlangen, Germany
| | - Nicolai Oetter
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), University Hospital Erlangen, Glückstraße 11, 91054, Erlangen, Germany
| | - Werner Adler
- Department of Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Waldstraße 6, 91054, Erlangen, Germany
| | | | - Michael Schmidt
- Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 6, 91052, Erlangen, Germany.,Bavarian Laser Center GmbH (blz), Konrad-Zuse-Straße 2-6, 91054, Erlangen, Germany.,Institute of Photonic Technologies, Friedrich-Alexander-University Erlangen-Nürnberg(FAU), Konrad-Zuse-Straße 3-5, 91052, Erlangen, Germany
| | - Christian Knipfer
- Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 6, 91052, Erlangen, Germany. .,Department of Oral and Maxillofacial Surgery, University of Hamburg (UHH), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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Willems NMBK, Langenbach GEJ, Stoop R, den Toonder JMJ, Mulder L, Zentner A, Everts V. Higher number of pentosidine cross-links induced by ribose does not alter tissue stiffness of cancellous bone. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 42:15-21. [PMID: 25063086 DOI: 10.1016/j.msec.2014.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 04/07/2014] [Accepted: 05/06/2014] [Indexed: 01/22/2023]
Abstract
The role of mature collagen cross-links, pentosidine (Pen) cross-links in particular, in the micromechanical properties of cancellous bone is unknown. The aim of this study was to examine nonenzymatic glycation effects on tissue stiffness of demineralized and non-demineralized cancellous bone. A total of 60 bone samples were derived from mandibular condyles of six pigs, and assigned to either control or experimental groups. Experimental handling included incubation in phosphate buffered saline alone or with 0.2M ribose at 37°C for 15 days and, in some of the samples, subsequent complete demineralization of the sample surface using 8% EDTA. Before and after experimental handling, bone microarchitecture and tissue mineral density were examined by means of microcomputed tomography. After experimental handling, the collagen content and the number of Pen, hydroxylysylpyridinoline (HP), and lysylpyridinoline (LP) cross-links were estimated using HPLC, and tissue stiffness was assessed by means of nanoindentation. Ribose treatment caused an up to 300-fold increase in the number of Pen cross-links compared to nonribose-incubated controls, but did not affect the number of HP and LP cross-links. This increase in the number of Pen cross-links had no influence on tissue stiffness of both demineralized and nondemineralized bone samples. These findings suggest that Pen cross-links do not play a significant role in bone tissue stiffness.
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Affiliation(s)
- Nop M B K Willems
- Dept. of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands; Dept. of Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands.
| | - Geerling E J Langenbach
- Dept. of Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Reinout Stoop
- Dept. of Metabolic Health Research, TNO, P.O. Box 2215, 2301 CE Leiden, The Netherlands
| | - Jaap M J den Toonder
- Dept. of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Lars Mulder
- Dept. of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Andrej Zentner
- Dept. of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Vincent Everts
- Dept. of Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
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Willems NMBK, Mulder L, den Toonder JMJ, Zentner A, Langenbach GEJ. The correlation between mineralization degree and bone tissue stiffness in the porcine mandibular condyle. J Bone Miner Metab 2014; 32:29-37. [PMID: 23624768 DOI: 10.1007/s00774-013-0464-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 03/21/2013] [Indexed: 11/26/2022]
Abstract
The aim of this study was to correlate the local tissue mineral density (TMD) with the bone tissue stiffness. It was hypothesized that these variables are positively correlated. Cancellous and cortical bone samples were derived from ten mandibular condyles taken from 5 young and 5 adult female pigs. The bone tissue stiffness was assessed in three directions using nanoindentation. At each of three tested sides 5 indents were made over the width of 5 single bone elements, resulting in a total number of 1500 indents. MicroCT was used to determine the local TMD at the indented sites. The TMD and the bone tissue stiffness were higher in bone from the adult animals than from the young ones, but did not differ between cancellous and cortical bone. In the adult group, both the TMD and the bone tissue stiffness were higher in the center than at the surface of the bone elements. The mean TMD, thus ignoring the local mineral distribution, had a coefficient of determination (R(2)) with the mean bone tissue stiffness of 0.55, p < 0.05, whereas the correlation between local bone tissue stiffness and the concomitant TMD appeared to be weak (R (2) 0.07, p < 0.001). It was concluded that the mineralization degree plays a larger role in bone tissue stiffness in cancellous than in cortical bone. Our data based on bone from the mandibular condyle suggest that the mineralization degree is not a decisive determinant of the local bone tissue stiffness.
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Affiliation(s)
- Nop M B K Willems
- Department of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands,
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Willems NMBK, Langenbach GEJ, Everts V, Zentner A. The microstructural and biomechanical development of the condylar bone: a review. Eur J Orthod 2013; 36:479-85. [PMID: 24375755 DOI: 10.1093/ejo/cjt093] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Bone constantly strives for optimal architecture. Mandibular condyle, which is subjected to various mechanical loads forcing it to be highly adaptive, has a unique structure and a relatively high remodelling rate. Despite the eminent clinical relevance of mandibular condyle, literature on its structural and biomechanical development and on the mechanical role of its mineralized and non-mineralized bone components is scarce. OBJECTIVE The aim of the present review is to provide a brief introduction to basic bone mechanics and a synopsis of the growth and development of human mandibular condyle. Subsequently, the current ideas on the relationship between the structural and biomechanical properties of bone in general and of mandibular condyle in particular are reviewed. Finally, up-to-date knowledge from fundamental bone research will be blended with the current knowledge relevant to clinical dentistry, above all orthodontics. METHODS A comprehensive literature study was performed with an emphasis on recent and innovative work focusing on the interaction between microarchitectural and micromechanical properties of bone. CONCLUSIONS Mandibular condyle is a bone structure with a high bone turnover rate. Mechanical properties of mandibular condyle improve during adolescence and are optimal during adulthood. Local mineralization degree might not be a decisive determinant of the local bone tissue stiffness as was believed hitherto. Bone collagen and its cross links play a role in toughness and tensile strength of bone but not in its compressive properties. Clinical procedures might affect mandibular condyle, which is highly reactive to changes in its mechanical environment.
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Affiliation(s)
- Nop M B K Willems
- Departments of *Orthodontics and**Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, the Netherlands
| | - Geerling E J Langenbach
- **Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, the Netherlands
| | - Vincent Everts
- **Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, the Netherlands
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Wilson SL, Guilbert M, Sulé-Suso J, Torbet J, Jeannesson P, Sockalingum GD, Yang Y. A microscopic and macroscopic study of aging collagen on its molecular structure, mechanical properties, and cellular response. FASEB J 2013; 28:14-25. [PMID: 24025727 DOI: 10.1096/fj.13-227579] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
During aging, collagen structure changes, detrimentally affecting tissues' biophysical and biomechanical properties due to an accumulation of advanced glycation end-products (AGEs). In this investigation, we conducted a parallel study of microscopic and macroscopic properties of different-aged collagens from newborn to 2-yr-old rats, to examine the effect of aging on fibrillogenesis, mechanical and contractile properties of reconstituted hydrogels from these collagens seeded with or without fibroblasts. In addition to fibrillogenesis of collagen under the conventional conditions, some fibrillogenesis was conducted alongside a 12-T magnetic field, and gelation rate and AGE content were measured. A nondestructive indentation technique and optical coherence tomography were used to determine the elastic modulus and dimensional changes, respectively. It was revealed that in comparison to younger specimens, older collagens exhibited higher viscosity, faster gelation rates, and a higher AGE-specific fluorescence. Exceptionally, only young collagens formed highly aligned fibrils under magnetic fields. The youngest collagen demonstrated a higher elastic modulus and contraction in comparison to the older collagen. We conclude that aging changes collagen monomer structure, which considerably affects the fibrillogenesis process, the architecture of the resulting collagen fibers and the global network, and the macroscopic properties of the formed constructs.
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Affiliation(s)
- Samantha L Wilson
- 1Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent, ST4 7QB, UK.
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Açil Y, Gierloff M, Behrens C, Möller B, Gassling V, Niehoff P, Wiltfang J, Simon M. Effects of zoledronate on irradiated bone in vivo: analysis of the collagen types I, V and their cross-links lysylpyridinoline, hydroxylysylpyridinoline and hydroxyproline. Calcif Tissue Int 2013. [PMID: 23179106 DOI: 10.1007/s00223-012-9676-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Radiotherapy can lead to a reduction of bone density with an increased risk of pathological fractures. Bisphosphonates may represent a preventive treatment option by increasing the density of anorganic bone mineral. Yet it is unknown how bisphosphonates act on irradiated collagen cross-links, which play an essential role for the mechanical stability of bone. The aim of this study was to evaluate the effects of zoledronate on bone collagens and their cross-links after irradiation. The right femur of 37 rats was irradiated with a single dose of 9.5 Gy at a high dose rate using an afterloading machine. Half of the rats (n=18) received additionally a single dose zoledronate (0.1 mg/kg body weight). Fourteen and 100 days after irradiation the femora were collected for histologic evaluation and determination of the collagen cross-links lysylpyridinoline, hydroxylysylpyridinoline, and hydroxyproline. The collagen types were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Fourteen days after treatment the lysylpyridinoline levels of all treatment groups were significantly lower compared to the untreated control. After 100 days, in the combined radiotherapy+zoledronate group significantly lower lysylpyridinoline values were determined (p=0.009). Radiotherapy and/or zoledronate did not change significantly the level of hydroxylysylpyridinoline. The concentration of hydroxyproline was 14 days after irradiation significantly higher in the combined treatment group compared to the control. No significant differences were observed 100 days after treatment. Zoledronate does not have the ability to restore the physiological bone collagen cross-link levels after radiotherapy. However, this would be necessary for regaining the physiological mechanical stability of bone after irradiation and therefore to prevent effectively radiation-induced fractures.
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Affiliation(s)
- Yahya Açil
- Department of Oral and Maxillofacial Surgery, UK-SH, Campus Kiel, Germany
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Willems NMBK, Mulder L, Bank RA, Grünheid T, den Toonder JMJ, Zentner A, Langenbach GEJ. Determination of the relationship between collagen cross-links and the bone-tissue stiffness in the porcine mandibular condyle. J Biomech 2011; 44:1132-6. [PMID: 21333996 DOI: 10.1016/j.jbiomech.2011.01.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 01/20/2011] [Accepted: 01/20/2011] [Indexed: 01/22/2023]
Abstract
Although bone-tissue stiffness is closely related to the degree to which bone has been mineralized, other determinants are yet to be identified. We, therefore, examined the extent to which the mineralization degree, collagen, and its cross-links are related to bone-tissue stiffness. A total of 50 cancellous and cortical bone samples were derived from the right mandibular condyles of five young and five adult female pigs. The degree of mineralization of bone (DMB) was assessed using micro-computed tomography. Using high-performance liquid chromatography, we quantified the collagen content and the number of cross-links per collagen molecule of two enzymatic cross-links: hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP), and one non-enzymatic cross-link: pentosidine (Pen). Nanoindentation was used to assess bone-tissue stiffness in three directions, and multiple linear regressions were used to calculate the correlation between collagen properties and bone-tissue stiffness, with the DMB as first predictor. Whereas the bone-tissue stiffness of cancellous bone did not differ between the three directions of nanoindentation, or between the two age groups, cortical bone-tissue stiffness was higher in the adult tissue. After correction for DMB, the cross-links studied did not increase the explained variance. In the young group, however, LP significantly improved the explained variance in bone-tissue stiffness. Approximately half of the variation in bone-tissue stiffness in cancellous and cortical bone was explained by the DMB and the LP cross-links and thus they cannot be considered the sole determinants of the bone-tissue stiffness.
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Affiliation(s)
- Nop M B K Willems
- Department of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, the Netherlands.
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