Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging

Sakari Karhula, Mikko A. Finnilä, Jonathan H. Freedman, Sami Kauppinen, Maarit Valkealahti, Petri Lehenkari, Kenneth P. H. Pritzker, Heikki Juhani Nieminen, Brian Snyder, Mark Grinstaff, Simo Saarakkala

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

Kuvaus

Contrast-enhanced micro-computed tomography (CE mu CT) with cationic and anionic contrast agents reveals glycosaminoglycan (GAG) content and distribution in articular cartilage (AC). The advantage of using cationic stains (e.g., CA4+) compared to anionic stains (e.g., Hexabrix (R)), is that it distributes proportionally with GAGs, while anionic stain distribution in AC is inversely proportional to the GAG content. To date, studies using cationic stains have been conducted with sufficient resolution to study its distributions on the macro-scale, but with insufficient resolution to study its distributions on the micro-scale. Therefore, it is not known whether the cationic contrast agents accumulate in extra/pericellular matrix and if they interact with chondrocytes. The insufficient resolution has also prevented to answer the question whether CA4+ accumulation in chondrons could lead to an erroneous quantification of GAG distribution with low-resolution mu CT setups. In this study, we use high-resolution mu CT to investigate whether CA4+ accumulates in chondrocytes, and further, to determine whether it affects the low-resolution ex vivo mu CT studies of CA4+ stained human AC with varying degree of osteoarthritis. Human osteochondral samples were immersed in three different concentrations of CA4+ (3 mgI/ml, 6 mgI/ml, and 24 mgI/ml) and imaged with high-resolution mu CT at several timepoints. Different uptake diffusion profiles of CA4+ were observed between the segmented chondrons and the rest of the tissue. While the X-ray -detected CA4+ concentration in chondrons was greater than in the rest of the AC, its contribution to the uptake into the whole tissue was negligible and in line with macro-scale GAG content detected from histology. The efficient uptake of CA4+ into chondrons and surrounding territorial matrix can be explained by the micro-scale distribution of GAG content. CA4+ uptake in chondrons occurred regardless of the progression stage of osteoarthritis in the samples and the relative difference between the interterritorial matrix and segmented chondron area was less than 4%. To conclude, our results suggest that GAG quantification with CE mu CT is not affected by the chondron uptake of CA4+. This further confirms the use of CA4+ for macro-scale assessment of GAG throughout the AC, and highlight the capability of studying chondron properties in 3D at the micro scale.
Alkuperäiskielienglanti
Artikkeli38
LehtiFrontiers in Physics
Vuosikerta5
Sivumäärä8
ISSN2296-424X
DOI - pysyväislinkit
TilaJulkaistu - 31 elokuuta 2017
OKM-julkaisutyyppiA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä, vertaisarvioitu

Tieteenalat

  • 114 Fysiikka
  • 217 Lääketieteen tekniikka

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Karhula, S., Finnilä, M. A., Freedman, J. H., Kauppinen, S., Valkealahti, M., Lehenkari, P., ... Saarakkala, S. (2017). Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging. Frontiers in Physics, 5, [38]. https://doi.org/10.3389/fphy.2017.00038
Karhula, Sakari ; Finnilä, Mikko A. ; Freedman, Jonathan H. ; Kauppinen, Sami ; Valkealahti, Maarit ; Lehenkari, Petri ; Pritzker, Kenneth P. H. ; Nieminen, Heikki Juhani ; Snyder, Brian ; Grinstaff, Mark ; Saarakkala, Simo. / Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging. Julkaisussa: Frontiers in Physics. 2017 ; Vuosikerta 5.
@article{448f983b2d4940d3a2384c9c8e848f58,
title = "Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging",
abstract = "Contrast-enhanced micro-computed tomography (CE mu CT) with cationic and anionic contrast agents reveals glycosaminoglycan (GAG) content and distribution in articular cartilage (AC). The advantage of using cationic stains (e.g., CA4+) compared to anionic stains (e.g., Hexabrix (R)), is that it distributes proportionally with GAGs, while anionic stain distribution in AC is inversely proportional to the GAG content. To date, studies using cationic stains have been conducted with sufficient resolution to study its distributions on the macro-scale, but with insufficient resolution to study its distributions on the micro-scale. Therefore, it is not known whether the cationic contrast agents accumulate in extra/pericellular matrix and if they interact with chondrocytes. The insufficient resolution has also prevented to answer the question whether CA4+ accumulation in chondrons could lead to an erroneous quantification of GAG distribution with low-resolution mu CT setups. In this study, we use high-resolution mu CT to investigate whether CA4+ accumulates in chondrocytes, and further, to determine whether it affects the low-resolution ex vivo mu CT studies of CA4+ stained human AC with varying degree of osteoarthritis. Human osteochondral samples were immersed in three different concentrations of CA4+ (3 mgI/ml, 6 mgI/ml, and 24 mgI/ml) and imaged with high-resolution mu CT at several timepoints. Different uptake diffusion profiles of CA4+ were observed between the segmented chondrons and the rest of the tissue. While the X-ray -detected CA4+ concentration in chondrons was greater than in the rest of the AC, its contribution to the uptake into the whole tissue was negligible and in line with macro-scale GAG content detected from histology. The efficient uptake of CA4+ into chondrons and surrounding territorial matrix can be explained by the micro-scale distribution of GAG content. CA4+ uptake in chondrons occurred regardless of the progression stage of osteoarthritis in the samples and the relative difference between the interterritorial matrix and segmented chondron area was less than 4{\%}. To conclude, our results suggest that GAG quantification with CE mu CT is not affected by the chondron uptake of CA4+. This further confirms the use of CA4+ for macro-scale assessment of GAG throughout the AC, and highlight the capability of studying chondron properties in 3D at the micro scale.",
keywords = "114 Physical sciences, 217 Medical engineering, CONTRAST AGENT, Articular cartilage, chondron, computed tomography, CA4+, CHONDROCYTES, AGE-RELATED-CHANGES",
author = "Sakari Karhula and Finnil{\"a}, {Mikko A.} and Freedman, {Jonathan H.} and Sami Kauppinen and Maarit Valkealahti and Petri Lehenkari and Pritzker, {Kenneth P. H.} and Nieminen, {Heikki Juhani} and Brian Snyder and Mark Grinstaff and Simo Saarakkala",
year = "2017",
month = "8",
day = "31",
doi = "10.3389/fphy.2017.00038",
language = "English",
volume = "5",
journal = "Frontiers in Physics",
issn = "2296-424X",
publisher = "Frontiers Media",

}

Karhula, S, Finnilä, MA, Freedman, JH, Kauppinen, S, Valkealahti, M, Lehenkari, P, Pritzker, KPH, Nieminen, HJ, Snyder, B, Grinstaff, M & Saarakkala, S 2017, 'Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging', Frontiers in Physics, Vuosikerta 5, 38. https://doi.org/10.3389/fphy.2017.00038

Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging. / Karhula, Sakari; Finnilä, Mikko A.; Freedman, Jonathan H.; Kauppinen, Sami; Valkealahti, Maarit; Lehenkari, Petri; Pritzker, Kenneth P. H.; Nieminen, Heikki Juhani; Snyder, Brian ; Grinstaff, Mark; Saarakkala, Simo.

julkaisussa: Frontiers in Physics, Vuosikerta 5, 38, 31.08.2017.

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

TY - JOUR

T1 - Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging

AU - Karhula, Sakari

AU - Finnilä, Mikko A.

AU - Freedman, Jonathan H.

AU - Kauppinen, Sami

AU - Valkealahti, Maarit

AU - Lehenkari, Petri

AU - Pritzker, Kenneth P. H.

AU - Nieminen, Heikki Juhani

AU - Snyder, Brian

AU - Grinstaff, Mark

AU - Saarakkala, Simo

PY - 2017/8/31

Y1 - 2017/8/31

N2 - Contrast-enhanced micro-computed tomography (CE mu CT) with cationic and anionic contrast agents reveals glycosaminoglycan (GAG) content and distribution in articular cartilage (AC). The advantage of using cationic stains (e.g., CA4+) compared to anionic stains (e.g., Hexabrix (R)), is that it distributes proportionally with GAGs, while anionic stain distribution in AC is inversely proportional to the GAG content. To date, studies using cationic stains have been conducted with sufficient resolution to study its distributions on the macro-scale, but with insufficient resolution to study its distributions on the micro-scale. Therefore, it is not known whether the cationic contrast agents accumulate in extra/pericellular matrix and if they interact with chondrocytes. The insufficient resolution has also prevented to answer the question whether CA4+ accumulation in chondrons could lead to an erroneous quantification of GAG distribution with low-resolution mu CT setups. In this study, we use high-resolution mu CT to investigate whether CA4+ accumulates in chondrocytes, and further, to determine whether it affects the low-resolution ex vivo mu CT studies of CA4+ stained human AC with varying degree of osteoarthritis. Human osteochondral samples were immersed in three different concentrations of CA4+ (3 mgI/ml, 6 mgI/ml, and 24 mgI/ml) and imaged with high-resolution mu CT at several timepoints. Different uptake diffusion profiles of CA4+ were observed between the segmented chondrons and the rest of the tissue. While the X-ray -detected CA4+ concentration in chondrons was greater than in the rest of the AC, its contribution to the uptake into the whole tissue was negligible and in line with macro-scale GAG content detected from histology. The efficient uptake of CA4+ into chondrons and surrounding territorial matrix can be explained by the micro-scale distribution of GAG content. CA4+ uptake in chondrons occurred regardless of the progression stage of osteoarthritis in the samples and the relative difference between the interterritorial matrix and segmented chondron area was less than 4%. To conclude, our results suggest that GAG quantification with CE mu CT is not affected by the chondron uptake of CA4+. This further confirms the use of CA4+ for macro-scale assessment of GAG throughout the AC, and highlight the capability of studying chondron properties in 3D at the micro scale.

AB - Contrast-enhanced micro-computed tomography (CE mu CT) with cationic and anionic contrast agents reveals glycosaminoglycan (GAG) content and distribution in articular cartilage (AC). The advantage of using cationic stains (e.g., CA4+) compared to anionic stains (e.g., Hexabrix (R)), is that it distributes proportionally with GAGs, while anionic stain distribution in AC is inversely proportional to the GAG content. To date, studies using cationic stains have been conducted with sufficient resolution to study its distributions on the macro-scale, but with insufficient resolution to study its distributions on the micro-scale. Therefore, it is not known whether the cationic contrast agents accumulate in extra/pericellular matrix and if they interact with chondrocytes. The insufficient resolution has also prevented to answer the question whether CA4+ accumulation in chondrons could lead to an erroneous quantification of GAG distribution with low-resolution mu CT setups. In this study, we use high-resolution mu CT to investigate whether CA4+ accumulates in chondrocytes, and further, to determine whether it affects the low-resolution ex vivo mu CT studies of CA4+ stained human AC with varying degree of osteoarthritis. Human osteochondral samples were immersed in three different concentrations of CA4+ (3 mgI/ml, 6 mgI/ml, and 24 mgI/ml) and imaged with high-resolution mu CT at several timepoints. Different uptake diffusion profiles of CA4+ were observed between the segmented chondrons and the rest of the tissue. While the X-ray -detected CA4+ concentration in chondrons was greater than in the rest of the AC, its contribution to the uptake into the whole tissue was negligible and in line with macro-scale GAG content detected from histology. The efficient uptake of CA4+ into chondrons and surrounding territorial matrix can be explained by the micro-scale distribution of GAG content. CA4+ uptake in chondrons occurred regardless of the progression stage of osteoarthritis in the samples and the relative difference between the interterritorial matrix and segmented chondron area was less than 4%. To conclude, our results suggest that GAG quantification with CE mu CT is not affected by the chondron uptake of CA4+. This further confirms the use of CA4+ for macro-scale assessment of GAG throughout the AC, and highlight the capability of studying chondron properties in 3D at the micro scale.

KW - 114 Physical sciences

KW - 217 Medical engineering

KW - CONTRAST AGENT

KW - Articular cartilage

KW - chondron

KW - computed tomography

KW - CA4+

KW - CHONDROCYTES

KW - AGE-RELATED-CHANGES

U2 - 10.3389/fphy.2017.00038

DO - 10.3389/fphy.2017.00038

M3 - Article

VL - 5

JO - Frontiers in Physics

JF - Frontiers in Physics

SN - 2296-424X

M1 - 38

ER -