The free diffusion of macromolecules in tissue-engineered skeletal muscle subjected to large compression strains
The free diffusion of macromolecules in tissue-engineered skeletal muscle subjected to large compression strains
Pressure-related deep tissue injury (DTI) represents a severe pressure ulcer, which initiates in compressed muscle tissue overlying a bony prominence and progresses to more superficial tissues until penetrating the skin. Individual subjects with impaired motor and/or sensory capacities are at high risk of developing DTI. Impaired diffusion of critical metabolites in compressed muscle tissue may contribute to DTI, and impaired diffusion of tissue damage biomarkers may further impose a problem in developing early detection blood tests. We hypothesize that compression of muscle tissue between a bony prominence and a supporting surface locally influences the diffusion capacity of muscle. The objective of this study was therefore, to determine the effects of large compression strains on free diffusion in a tissue-engineered skeletal muscle model. Diffusion was measured with a range of fluorescently labeled dextran molecules (10, 20, 150 kDa) whose sizes were representative of both hormones and damage biomarkers. We used fluorescence recovery after photobleaching (FRAP) to compare diffusion coefficients (D) of the different dextrans between the uncompressed and compressed (48–60% strain) states. In a separate experiment, we simulated the effects of local partial muscle ischemia in vivo, by reducing the temperature of compressed specimens from 37 to 34 °C. Compared to the D in the uncompressed model system, values in the compressed state were significantly reduced by 47±22% (p<0.02). A 3 °C temperature decrease further reduced D in the compressed specimens by 10±6% (p<0.05). In vivo, the effects of large strains and ischemia are likely to be summative, and hence, the present findings suggest an important role of impaired diffusion in the etiology of DTI, and should also be considered when developing biochemical screening methods for early detection of DTI.
pressure ulcer, deep tissue injury, dextran, confocal microscopy, FRAP
845-853
Gefen, Amit
85d29654-5b34-472a-91ac-b2a31c590ea9
Cornelissen, Lisette H.
0d29fd72-62d3-4748-bbd5-f309eadfcc54
Gawlitta, Debby
24893094-a770-486a-8ef9-723207a6c2e3
Bader, Dan L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Oomens, Cees W.J.
e8a85b85-3719-4909-9f82-4f03d8a43263
2008
Gefen, Amit
85d29654-5b34-472a-91ac-b2a31c590ea9
Cornelissen, Lisette H.
0d29fd72-62d3-4748-bbd5-f309eadfcc54
Gawlitta, Debby
24893094-a770-486a-8ef9-723207a6c2e3
Bader, Dan L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Oomens, Cees W.J.
e8a85b85-3719-4909-9f82-4f03d8a43263
Gefen, Amit, Cornelissen, Lisette H., Gawlitta, Debby, Bader, Dan L. and Oomens, Cees W.J.
(2008)
The free diffusion of macromolecules in tissue-engineered skeletal muscle subjected to large compression strains.
Journal of Biomechanics, 41 (4), .
(doi:10.1016/j.jbiomech.2007.10.023).
(PMID:18068175)
Abstract
Pressure-related deep tissue injury (DTI) represents a severe pressure ulcer, which initiates in compressed muscle tissue overlying a bony prominence and progresses to more superficial tissues until penetrating the skin. Individual subjects with impaired motor and/or sensory capacities are at high risk of developing DTI. Impaired diffusion of critical metabolites in compressed muscle tissue may contribute to DTI, and impaired diffusion of tissue damage biomarkers may further impose a problem in developing early detection blood tests. We hypothesize that compression of muscle tissue between a bony prominence and a supporting surface locally influences the diffusion capacity of muscle. The objective of this study was therefore, to determine the effects of large compression strains on free diffusion in a tissue-engineered skeletal muscle model. Diffusion was measured with a range of fluorescently labeled dextran molecules (10, 20, 150 kDa) whose sizes were representative of both hormones and damage biomarkers. We used fluorescence recovery after photobleaching (FRAP) to compare diffusion coefficients (D) of the different dextrans between the uncompressed and compressed (48–60% strain) states. In a separate experiment, we simulated the effects of local partial muscle ischemia in vivo, by reducing the temperature of compressed specimens from 37 to 34 °C. Compared to the D in the uncompressed model system, values in the compressed state were significantly reduced by 47±22% (p<0.02). A 3 °C temperature decrease further reduced D in the compressed specimens by 10±6% (p<0.05). In vivo, the effects of large strains and ischemia are likely to be summative, and hence, the present findings suggest an important role of impaired diffusion in the etiology of DTI, and should also be considered when developing biochemical screening methods for early detection of DTI.
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Published date: 2008
Keywords:
pressure ulcer, deep tissue injury, dextran, confocal microscopy, FRAP
Organisations:
Medicine
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Local EPrints ID: 169025
URI: http://eprints.soton.ac.uk/id/eprint/169025
ISSN: 0021-9290
PURE UUID: 7dde6c7a-34b6-40aa-84dd-65065f77e74f
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Date deposited: 08 Dec 2010 14:39
Last modified: 14 Mar 2024 02:19
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Author:
Amit Gefen
Author:
Lisette H. Cornelissen
Author:
Debby Gawlitta
Author:
Cees W.J. Oomens
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