Age-related degenerative functional, radiographic, and histological changes of the shoulder in nonhuman primates.
BACKGROUND
Nonhuman primates have similar shoulder anatomy and physiology compared to humans, and may represent a previously underutilized model for shoulder research. This study sought to identify naturally occurring bony and muscular degeneration in the shoulder of nonhuman primates and to assess relationships between structural and functional aspects of the shoulder and measures of physical function of the animals. We hypothesized that age-related degenerative changes in the shoulders of nonhuman primates would resemble those observed in aging humans.


METHODS
Middle-aged (n = 5; ages 9.4-11.8 years) and elderly (n = 6; ages 19.8-26.4 years) female vervet monkeys were studied for changes in mobility and shoulder function, and radiographic and histologic signs of age-related degeneration.


RESULTS
Four out of 6 (4/6) elderly animals had degenerative changes of the glenoid compared to 0/5 of the middle-aged animals (P = .005). Elderly animals had glenoid retroversion, decreased joint space, walked slower, and spent less time climbing and hanging than middle-aged vervets (P < .05). Physical mobility and shoulder function correlated with glenoid version angle (P < .05). Supraspinatus muscles of elderly animals were less dense (P = .001), had decreased fiber cross-sectional area (P < .001), but similar amounts of nuclear material (P = .085). Degenerative rotator cuff tears were not observed in any of the eleven animals.


CONCLUSIONS
The vervet monkey naturally undergoes age-related functional, radiographic and histological changes of the shoulder, and may qualify as an animal model for selected translational research of shoulder osteoarthritis.
Department of Orthopaedic Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA. jplate@wakehealth.edu
Johannes F
JF
Plate
Christopher M
CM
Bates
Sandeep
S
Mannava
Thomas L
TL
Smith
Matthew J
MJ
Jorgensen
Thomas C
TC
Register
John R
JR
Stehle
Kevin P
KP
High
Carol A
CA
Shively
Jay R
JR
Kaplan
Katherine R
KR
Saul
Christopher J
CJ
Tuohy
D000375:Aging / Q000473:pathology* / Q000502:physiology*; D000818:Animals; D002522:Chlorocebus aethiops; D005260:Female; D023421:Models, Animal; D009043:Motor Activity / Q000502:physiology*; D010003:Osteoarthritis / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D016059:Range of Motion, Articular; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed
Animal model; Basic Science Study; aging; degeneration; in-vivo Animal Model; osteoarthritis; rotator cuff; shoulder; vervet monkey