Age-related variation in cell density of human lumbar intervertebral disc.
METHODS
changes in cell density of endplate (EP), nucleus pulposus (NP), and anulus fibrosus (AF) during ageing were systematically investigated in defined regions of interest in complete human motion segments.


OBJECTIVE
to elucidate cell density and total cell number in distinct anatomic regions of the intervertebral disc; to test effects of gender, level and age on cell density; and to correlate changes in cell density with histologic signs of disc degeneration.


BACKGROUND
the available information on the cell density within intervertebral discs and its age-related changes is sparse. This knowledge, however, is a crucial prerequisite for cell-based tissue engineering approaches of the intervertebral disc.


METHODS
in 49 complete cross-sections from lumbar motion segments (newborn to 86 years) from 22 specimens, cell density was determined by the Abercrombie method in EP, NP, and AF, and total cell number was counted per region of interest.


RESULTS
cell density in EP, NP, and AF decreased significantly from 0 to 16 years with the main changes occuring from 0 to 3 years for NP and AF. No significant variations were observed thereafter. We found a significant correlation of cell density and histologic degeneration score between 0 and 1, but not for scores >1. Gender and disc level did not influence cell density.


CONCLUSIONS
This study provides data concerning the total number of cells in the various regions of the intervertebral disc for different age groups. This knowledge will be beneficial for cell-based treatment approaches, which may evolve in the future.
Liebscher
Thomas
T
Centre for Spinal Surgery, University of Zurich, University Hospital Balgrist, Forchstrasse, Zurich, Switzerland.
Haefeli
Mathias
M
Wuertz
Karin
K
Nerlich
Andreas G
AG
Boos
Norbert
N
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D002452:Cell Count; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007403:Intervertebral Disc / Q000033:anatomy & histology / Q000166:cytology*; D055959:Intervertebral Disc Degeneration / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D055815:Young Adult