Compressive Mechanical Properties of the Human Anulus Fibrosus and Their Relationship to Biochemical Composition

Best, Barbara; Guilak, Farhid; Setton, Lori A.; Zhu, Wenbo; Saed‐Nejad, Fatemeh; Ratcliffe, Anthony; Weidenbaum, Mark; Mow, Van C.

doi:10.1097/00007632-199401001-00017

Cited by 198 publications

(106 citation statements)

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“…Prior work has established that regional differences in material properties and biochemical composition exist between the NP and AF of the intervertebral disc, 30,31 and that within the AF, these material and biochemical attributes are also known to vary with radial position. 32 Glycosaminoglycan concentration, 33 collagen type, 34 and elastic fiber density 29 are all known to vary between the inner and outer portions of the AF. These variations may be due, at least in part, to differences in the cell populations found in these different regions and their corresponding biosynthetic capabilities.…”

Section: Regional Variation Of Lubricin In the Intervertebral Discmentioning

confidence: 99%

The presence and distribution of lubricin in the caprine intervertebral disc

Shine¹,

Spector²

2008

Journal Orthopaedic Research

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Lubricin is a large, multifunctional glycoprotein that is known to play a role as a boundary lubricant in diarthrodial joint articulation. The hypothesis of this study was that lubricin is present in the intervertebral disc in a distribution consistent with serving to facilitate interlamellar tribology. The objectives were to: (1) determine the distribution of lubricin in the normal caprine disc; and (2) investigate the synthesis of lubricin by caprine annulus fibrosus (AF) and nucleus pulposus (NP) cells in vitro, using immunohistochemical methods. Caprine lumbar intervertebral discs from five levels and four animals were studied. Positive staining revealed the presence of the lubricin in the outer AF of nearly all samples. No staining was present in the inner AF or the NP. Within the outer AF, lubricin was prominent in the layers separating lamellae and in the extracellular matrix of the lamellae. Some of the AF cells within the lubricin-positive regions demonstrated intracellular lubricin staining, suggesting that these cells may be synthesizing the lubricin protein observed. Immunohistochemistry performed on monolayer cultures of primary AF and NP cells demonstrated intracellular lubricin staining in both cell types. Thus, lubricin is selectively present in the outer caprine intervertebral disc AF, and its distribution suggests that it may play a role in interlamellar tribology. Cells from both the annulus and nucleus were found capable of synthesizing lubricin in vitro, suggesting that these cells may be a potential source of the glycoprotein under some conditions. ß

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Section: Regional Variation Of Lubricin In the Intervertebral Discmentioning

confidence: 99%

The presence and distribution of lubricin in the caprine intervertebral disc

Shine¹,

Spector²

2008

Journal Orthopaedic Research

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“…The osmotic pressure of the IVD is mainly due to the high density of charged carboxyl and sulfate groups on the glycosaminoglycans of the proteoglycans within the tissue (Urban and Maroudas, 1980;Urban et al, 1979). When an IVD is deformed under loading, interstitial fluid flow occurs, even though the hydraulic permeability of the tissue is very low (Best et al, 1994;Gu et al, 1999a;Gu and Yao, 2003;Houben et al, 1997;Iatridis et al, 1998;Perie et al, 2005). The electrical response of the IVD also changes when a disc is compressed (Yao and Gu, 2007b), due to the effects of diffusion potential and streaming potential (Lai et al, 2000;Gu et al, 1999b).…”

Section: Introductionmentioning

confidence: 99%

Effects of mechanical compression on metabolism and distribution of oxygen and lactate in intervertebral disc

Huang¹,

Gu²

2008

Journal of Biomechanics

103

129

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The objective of this study was to examine the effects of mechanical compression on metabolism and distributions of oxygen and lactate in the intervertebral disc (IVD) using a new formulation of the triphasic theory. In this study, the cellular metabolic rates of oxygen and lactate were incorporated into the newly developed formulation of the mechano-electrochemical mixture model [Huang and Gu, J. Biomech. Eng., 129:423-429, 2007]. The model was used to numerically analyze metabolism and transport of oxygen and lactate in the IVD under static or dynamic compression. The theoretical analyses demonstrated that compressive loading could affect transport and metabolism of nutrients. Dynamic compression increased oxygen concentration, reduced lactate accumulation, and promoted oxygen consumption and lactate production (i.e., energy conversion) within the IVD. Such effects of dynamic loading were dependent on strain level and loading frequency, and more pronounced in the IVD with less permeable endplate. In contrast, static compression exhibited inverse effects on transport and metabolism of oxygen and lactate. The theoretical predictions in this study are in good agreement with those in the literature. This study established a new theoretical model for analyzing cellular metabolism of nutrients in hydrated, fibrous soft tissues under mechanical compression.

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“…Lumbar intervertebral discs change morphologically, biochemically, and biomechanically with advancing age, [1][2][3][4][5][6][7][8][9][10] changes that are characterized as disc degeneration and are implicated as the origin of low back pain. Unfortunately, the initiating and perpetuating factors of disc degeneration are unknown, so despite the pain, disability, and economic loss associated with disc degeneration, intervention and mitigation strategies cannot effectively proceed.…”

mentioning

confidence: 99%

“…[13][14][15][16] The altered biomechanical response of degenerate disc tissues have been measured. [2][3][4][17][18][19][20][21][22][23][24] Disc stiffness decreases with low-grade degeneration and increases with the most severe degeneration, while energy absorption decreases throughout degeneration. Further, spinal segment range of motion and neutral zone increase with advancing degeneration up to the most severely degenerated discs, where these properties reverse course with increasing stiffness.…”

mentioning

confidence: 99%

Intervertebral disc degeneration in a naturally occurring primate model: Radiographic and biomechanical evidence

Nuckley

Kramer

Rosario

et al. 2008

Journal Orthopaedic Research

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Classic degenerative disc disease is a serious health problem worldwide, whose etiological basis-mechanical stimulus, biochemical changes, or natural aging-is poorly understood. Animal models are critical to the study of degenerative disc disease initiation and progression and for attempts to regulate, ameliorate, or eliminate it. The macaque represents a primate model with natural disc degeneration that might serve to advance the field; we aimed to provide radiographic (morphologic) and biomechanical evidence of natural disc degeneration in this model. A factorial study design was used to examine the relationship between the radiographic appearance of disc degeneration and its biomechanical consequences. Eighteen macaques of advanced age (22.3 AE 0.9 years) had radiographs taken to assess the degree of thoracolumbar intervertebral disc degeneration using a standard atlas method. Each spine was harvested and dynamic biomechanical tests were performed. Advancing disc degeneration (degree of disc space narrowing and osteophytosis) was associated with increased stiffness, decreased energy absorption, and increased natural frequency of the intervertebral disc. These associations linking the dynamics of the intervertebral disc and its degree of degeneration are similar to those found in humans. Our results indicate the macaque model with morphologic and biomechanical efficacy could aid in understanding the progression of disc degeneration and in developing therapeutic strategies to prevent or inhibit its course. Keywords: intervertebral disc; disc degeneration; Macaca fascicularis; disc dynamics; biomechanics Lumbar intervertebral discs change morphologically, biochemically, and biomechanically with advancing age, 1-10 changes that are characterized as disc degeneration and are implicated as the origin of low back pain. Unfortunately, the initiating and perpetuating factors of disc degeneration are unknown, so despite the pain, disability, and economic loss associated with disc degeneration, intervention and mitigation strategies cannot effectively proceed. Morphologically, dehydration and diminished cellularity of the nucleus pulposus and disorganization and lesions of the annulus fibrosus demarcate disc degeneration. These changes manifest as decreased disc height, increased radial bulging, and osteophyte formation. 11,12 Morphologic changes are intrinsically tied to the biochemistry and biomechanics of the system, and visible and radiographic changes are used to define gradations of disc degeneration. [13][14][15][16] The altered biomechanical response of degenerate disc tissues have been measured. [2][3][4][17][18][19][20][21][22][23][24] Disc stiffness decreases with low-grade degeneration and increases with the most severe degeneration, while energy absorption decreases throughout degeneration. Further, spinal segment range of motion and neutral zone increase with advancing degeneration up to the most severely degenerated discs, where these properties reverse course with increasing stiffness. Unfortun...

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Compressive Mechanical Properties of the Human Anulus Fibrosus and Their Relationship to Biochemical Composition

Cited by 198 publications

References 0 publications

The presence and distribution of lubricin in the caprine intervertebral disc

The presence and distribution of lubricin in the caprine intervertebral disc

Effects of mechanical compression on metabolism and distribution of oxygen and lactate in intervertebral disc

Intervertebral disc degeneration in a naturally occurring primate model: Radiographic and biomechanical evidence

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