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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

Stained area per collagen type (%).Predominance of collagen type II in G1 and an approximate 60% reduction in G2. Vertical arrows indicate p < .05 in G1 vs. G2 comparison; black asterisks mark p < .05 in anterior vs. posterior comparison and are located in the frame with the higher expression. NS, staining not significant. Error bars represent standard error of the mean.
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pone.0139283.g005: Stained area per collagen type (%).Predominance of collagen type II in G1 and an approximate 60% reduction in G2. Vertical arrows indicate p < .05 in G1 vs. G2 comparison; black asterisks mark p < .05 in anterior vs. posterior comparison and are located in the frame with the higher expression. NS, staining not significant. Error bars represent standard error of the mean.

Mentions: All tested collagen types stained an area larger than that stained in either negative controls in every disc sector in both G1 and G2 with the exception of collagen X (Fig 5). Qualitative analysis demonstrated two main staining patterns. Collagens I, II, IV and IX had predominantly extracellular, filiform reactivity within the structural bundles composing the lamellae of the AF (Fig 6). Intra- and peri-cellular reactivity was seen with collagens III, V and VI, although collagen V was mainly present next to the vertebral endplates. The area stained by collagen X antibodies was not significantly different than the negative controls except in the anterior AF of G1 discs; when present, its expression was similar to the filiform pattern.


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)

Stained area per collagen type (%).Predominance of collagen type II in G1 and an approximate 60% reduction in G2. Vertical arrows indicate p < .05 in G1 vs. G2 comparison; black asterisks mark p < .05 in anterior vs. posterior comparison and are located in the frame with the higher expression. NS, staining not significant. Error bars represent standard error of the mean.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0139283.g005: Stained area per collagen type (%).Predominance of collagen type II in G1 and an approximate 60% reduction in G2. Vertical arrows indicate p < .05 in G1 vs. G2 comparison; black asterisks mark p < .05 in anterior vs. posterior comparison and are located in the frame with the higher expression. NS, staining not significant. Error bars represent standard error of the mean.
Mentions: All tested collagen types stained an area larger than that stained in either negative controls in every disc sector in both G1 and G2 with the exception of collagen X (Fig 5). Qualitative analysis demonstrated two main staining patterns. Collagens I, II, IV and IX had predominantly extracellular, filiform reactivity within the structural bundles composing the lamellae of the AF (Fig 6). Intra- and peri-cellular reactivity was seen with collagens III, V and VI, although collagen V was mainly present next to the vertebral endplates. The area stained by collagen X antibodies was not significantly different than the negative controls except in the anterior AF of G1 discs; when present, its expression was similar to the filiform pattern.

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