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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

Scanning electron microscopy.G1 (A-D) and G2 (E-H) cervical specimens. AF of G1 composed of alternating lamellae while longitudinal bundles predominate in the posterior AF. Insertion of the AF into the endplate (*) is perpendicular in the anterior AF and obtuse in the posterior AF. A central area of loose connective tissue without endplate insertion is present in both G1 and G2 specimens (**). Th, Thompson grade.
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pone.0139283.g004: Scanning electron microscopy.G1 (A-D) and G2 (E-H) cervical specimens. AF of G1 composed of alternating lamellae while longitudinal bundles predominate in the posterior AF. Insertion of the AF into the endplate (*) is perpendicular in the anterior AF and obtuse in the posterior AF. A central area of loose connective tissue without endplate insertion is present in both G1 and G2 specimens (**). Th, Thompson grade.

Mentions: The superficial layers of the anterior and posterior AF were indistinct from the anterior (ALL) or posterior (PLL) longitudinal ligaments, while the pattern of intertwined lamellae predominates in deeper areas (Fig 4). A fine diagonal mesh can be seen between G1 lamellae. Endplate insertion was perpendicular in the anterior AF and obtuse in the posterior AF. SEM was the only method that could visualize the NP as a separate structure in all specimens due to its lack of lamellar organization and endplate insertion and greater retraction due to higher water content than the AF, regardless of the extent of degeneration. In G2 specimens, the AF matrix was far denser resulting in little space between lamellae, with preserved endplate insertion.


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)

Scanning electron microscopy.G1 (A-D) and G2 (E-H) cervical specimens. AF of G1 composed of alternating lamellae while longitudinal bundles predominate in the posterior AF. Insertion of the AF into the endplate (*) is perpendicular in the anterior AF and obtuse in the posterior AF. A central area of loose connective tissue without endplate insertion is present in both G1 and G2 specimens (**). Th, Thompson grade.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0139283.g004: Scanning electron microscopy.G1 (A-D) and G2 (E-H) cervical specimens. AF of G1 composed of alternating lamellae while longitudinal bundles predominate in the posterior AF. Insertion of the AF into the endplate (*) is perpendicular in the anterior AF and obtuse in the posterior AF. A central area of loose connective tissue without endplate insertion is present in both G1 and G2 specimens (**). Th, Thompson grade.
Mentions: The superficial layers of the anterior and posterior AF were indistinct from the anterior (ALL) or posterior (PLL) longitudinal ligaments, while the pattern of intertwined lamellae predominates in deeper areas (Fig 4). A fine diagonal mesh can be seen between G1 lamellae. Endplate insertion was perpendicular in the anterior AF and obtuse in the posterior AF. SEM was the only method that could visualize the NP as a separate structure in all specimens due to its lack of lamellar organization and endplate insertion and greater retraction due to higher water content than the AF, regardless of the extent of degeneration. In G2 specimens, the AF matrix was far denser resulting in little space between lamellae, with preserved endplate insertion.

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