Limits...
Structural and Ultrastructural Analysis of the Cervical Discs of Young and Elderly Humans.

Fontes RB, Baptista JS, Rabbani SR, Traynelis VC, Liberti EA - PLoS ONE (2015)

Bottom Line: Macroscopic degenerative features such as loss of annulus-nucleus distinction and fissures were found in both groups and significantly more severe in G2 as expected.Collagen detection was significantly decreased in G2: although significant intradiscal differences were rare, changes may occur faster or earlier in the posterior annulus.These results demonstrate an extensive modification of the ECM with maintenance of basic ultrastructural features despite severe macroscopic degeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; Department of Neurosurgery, Rush University Medical Center, Chicago, IL, United States of America.

ABSTRACT
Several studies describing the ultrastructure and extracellular matrix (ECM) of intervertebral discs (IVDs) involve animal models and specimens obtained from symptomatic individuals during surgery for degenerative disease or scoliosis, which may not necessarily correlate to changes secondary to normal aging in humans. These changes may also be segment-specific based on different load patterns throughout life. Our objective was to describe the ECM and collagen profile of cervical IVDs in young (G1 - <35 years) and elderly (G2 - >65 years) presumably-asymptomatic individuals. Thirty cervical discs per group were obtained during autopsies of presumably-asymptomatic individuals. IVDs were analyzed with MRI, a morphological grading scale, light microscopy, scanning electron microscopy (SEM) and immunohistochemistry (IHC) for collagen types I, II, III, IV, V, VI, IX and X. Macroscopic degenerative features such as loss of annulus-nucleus distinction and fissures were found in both groups and significantly more severe in G2 as expected. MRI could not detect all morphological changes when compared even with simple morphological inspection. The loose fibrocartilaginous G1 matrix was replaced by a denser ECM in G2 with predominantly cartilaginous characteristics, chondrocyte clusters and absent elastic fibers. SEM demonstrated persistence of an identifiable nucleus and Sharpey-type insertion of cervical annulus fibers even in highly-degenerated G2 specimens. All collagen types were detected in every disc sector except for collagen X, with the largest area stained by collagens II and IV. Collagen detection was significantly decreased in G2: although significant intradiscal differences were rare, changes may occur faster or earlier in the posterior annulus. These results demonstrate an extensive modification of the ECM with maintenance of basic ultrastructural features despite severe macroscopic degeneration. Collagen analysis supports there is not a "pathologic" collagen type and changes are generally similar throughout the disc. Understanding the collagen and ultrastructural substrate of degenerative changes in the human disc is an essential step in planning restorative therapies.

No MeSH data available.


Related in: MedlinePlus

Distribution of Okada (n = 10) and Thompson (n = 30) scores per group.Bars represent median and interquartile range. Comparison performed with Mann-Whitney test.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4591259&req=5

pone.0139283.g002: Distribution of Okada (n = 10) and Thompson (n = 30) scores per group.Bars represent median and interquartile range. Comparison performed with Mann-Whitney test.

Mentions: Cervical discs from G1 were not devoid of degenerative findings, though these were generally incipient (Figs 1 and 2). The most common finding in G1 was simply the loss of AF-NP distinction; when more advanced findings were seen, these were mostly horizontal tears. These tears were usually confined to only one of the two discs in each segment, occasionally leading to widely different Okada scores within the same cadaver. In G2, advanced degeneration was usually manifested as complete disc collapse (Fig 1), which typically impacted both graded discs in a similar manner. Semi-qualitative grading confirmed progression of degenerative features from G1 to G2 as expected (p = .005 - Fig 2).


Structural and Ultrastructural Analysis of the Cervical Discs of Young and Elderly Humans.

Fontes RB, Baptista JS, Rabbani SR, Traynelis VC, Liberti EA - PLoS ONE (2015)

Distribution of Okada (n = 10) and Thompson (n = 30) scores per group.Bars represent median and interquartile range. Comparison performed with Mann-Whitney test.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591259&req=5

pone.0139283.g002: Distribution of Okada (n = 10) and Thompson (n = 30) scores per group.Bars represent median and interquartile range. Comparison performed with Mann-Whitney test.
Mentions: Cervical discs from G1 were not devoid of degenerative findings, though these were generally incipient (Figs 1 and 2). The most common finding in G1 was simply the loss of AF-NP distinction; when more advanced findings were seen, these were mostly horizontal tears. These tears were usually confined to only one of the two discs in each segment, occasionally leading to widely different Okada scores within the same cadaver. In G2, advanced degeneration was usually manifested as complete disc collapse (Fig 1), which typically impacted both graded discs in a similar manner. Semi-qualitative grading confirmed progression of degenerative features from G1 to G2 as expected (p = .005 - Fig 2).

Bottom Line: Macroscopic degenerative features such as loss of annulus-nucleus distinction and fissures were found in both groups and significantly more severe in G2 as expected.Collagen detection was significantly decreased in G2: although significant intradiscal differences were rare, changes may occur faster or earlier in the posterior annulus.These results demonstrate an extensive modification of the ECM with maintenance of basic ultrastructural features despite severe macroscopic degeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; Department of Neurosurgery, Rush University Medical Center, Chicago, IL, United States of America.

ABSTRACT
Several studies describing the ultrastructure and extracellular matrix (ECM) of intervertebral discs (IVDs) involve animal models and specimens obtained from symptomatic individuals during surgery for degenerative disease or scoliosis, which may not necessarily correlate to changes secondary to normal aging in humans. These changes may also be segment-specific based on different load patterns throughout life. Our objective was to describe the ECM and collagen profile of cervical IVDs in young (G1 - <35 years) and elderly (G2 - >65 years) presumably-asymptomatic individuals. Thirty cervical discs per group were obtained during autopsies of presumably-asymptomatic individuals. IVDs were analyzed with MRI, a morphological grading scale, light microscopy, scanning electron microscopy (SEM) and immunohistochemistry (IHC) for collagen types I, II, III, IV, V, VI, IX and X. Macroscopic degenerative features such as loss of annulus-nucleus distinction and fissures were found in both groups and significantly more severe in G2 as expected. MRI could not detect all morphological changes when compared even with simple morphological inspection. The loose fibrocartilaginous G1 matrix was replaced by a denser ECM in G2 with predominantly cartilaginous characteristics, chondrocyte clusters and absent elastic fibers. SEM demonstrated persistence of an identifiable nucleus and Sharpey-type insertion of cervical annulus fibers even in highly-degenerated G2 specimens. All collagen types were detected in every disc sector except for collagen X, with the largest area stained by collagens II and IV. Collagen detection was significantly decreased in G2: although significant intradiscal differences were rare, changes may occur faster or earlier in the posterior annulus. These results demonstrate an extensive modification of the ECM with maintenance of basic ultrastructural features despite severe macroscopic degeneration. Collagen analysis supports there is not a "pathologic" collagen type and changes are generally similar throughout the disc. Understanding the collagen and ultrastructural substrate of degenerative changes in the human disc is an essential step in planning restorative therapies.

No MeSH data available.


Related in: MedlinePlus