Retinal morphology and visual pigment levels in 6- and 12-month-old rhesus monkeys fed a taurine-free human infant formula.
Rhesus monkey infants were raised from birth until 6 or 12 months of age on a taurine-free soy protein-based human infant formula or on the same formula supplemented with taurine. An additional group received taurine-free formula until 6 months and then the supplemented diet from 6 until 12 months. The densities of rod and cone visual pigments were measured by fundus reflectometry at 6 and 12 months, and retinal morphology was then examined by light and electron microscopy. The densities of rhodopsin, measured in the near periphery after a white bleach, and of cone pigment, measured in the macula after a red bleach, were significantly reduced in the taurine-deprived monkeys at 6 months but not at 12 months. The retinas of 6-month-old taurine-deprived infants showed degenerative morphological changes in photoreceptors, particularly in cones in the foveal region, which were somewhat less severe than those seen in a previous study at 3 months of age. The prevalence and degree of these abnormalities continued to decrease with age in taurine-deprived animals, but changes persisted in some animals at 12 months. Recovery was more complete in monkeys reversed to the supplemented diet from 6 to 12 months. Thus, monkey infants are dependent on dietary taurine to maintain normal retinal structure until at least 6 months of age; the effects of taurine deprivation regress spontaneously but incompletely by 12 months.
Imaki
H
H
Department of Developmental Biochemistry, New York State Office of Mental Retardation and Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island 10314.
Jacobson
S G
SG
Kemp
C M
CM
Knighton
R W
RW
Neuringer
M
M
Sturman
J
J
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D002467:Cell Nucleus / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D006801:Humans; D007223:Infant; D007225:Infant Food; D008253:Macaca mulatta; D008854:Microscopy, Electron; D009887:Ophthalmoscopy; D012160:Retina / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D012168:Retinal Pigments / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism / Q000648:ultrastructure; D012243:Rhodopsin / Q000378:metabolism; D013654:Taurine / Q000008:administration & dosage / Q000172:deficiency*
D012168:Retinal Pigments; D013654:Taurine; D012243:Rhodopsin