TY - JOUR
T1 - Effects of xylose on monkey lenses in organ culture
T2 - A model for study of sugar cataracts in a primate
AU - Jernigan, Howard M.
AU - Zigler, J. Samuel
AU - Liu, Ying
AU - Blum, Penny S.
AU - Merola, Lorenzo O.
AU - Stimbert, Cynthia D.
N1 - Funding Information:
This research was supported in part by National Institutes of Health research grant EY07938 (HMJ) and by an unrestricted grant from Research to Prevent Blindness, New York, NY, U.S.A. (to Univ. TN, Department of Ophthalmology). The authors wish to thank Dr John Cogan of the Center for Biologics Evaluation and Research (Food and Drug Administration) for providing the rhesus monkey eyes, the Mid South Eye Bank, Memphis, Tennessee, U.S.A. for providing the human eyes, and Dr W. G. Robison, Jr for advice and assistance in histological analyses.
PY - 1998/7
Y1 - 1998/7
N2 - Lenses exposed to high concentrations of xylose in organ culture produce xylitol, and they lose transparency and exhibit other changes characteristic of cataracts. Most previous studies of this model system for cataractogenesis have employed rat or rabbit lenses, where the activity of the enzyme aldose reductase has been definitely implicated as the initiating factor. Since lenses from this species have much higher aldose reductase activity and have other differences relative to human lenses, the relevance of these findings to the human lens is uncertain. To determine the effects of xylose on the lenses of a primate, lenses from the rhesus monkey (Macaca mulatta) were incubated 24-48 hr in control medium or in TC-199 medium containing 30 mM xylose. Xylose caused a general haziness, focal swelling of epithelial cells, and swollen peripheral fiber cells, but the changes were much less pronounced than in rat lenses under similar conditions. Monkey lenses exposed to 30 mM glucose, galactose or xylose accumulated measurable sorbitol, dulcitol or xylitol, respectively, but the mounts were much lower than in rat lenses, perhaps reflecting the lower aldose reductase and higher sorbitol dehydrogenase activities in monkey lenses. The damage to monkey lenses appeared to be limited to the outer layers. In monkey lenses, xylose caused little, if any, change in membrane transport of choline or α- aminoisobutyrate, but severely depressed synthesis of phosphorylcholine (P- choline), and increased leakage of P-choline into the culture medium, leading to a decrease in the P-choline concentration within 24-48 hr. In summary, xylose- induced damage to monkey lenses in organ culture is qualitatively similar to that seen in rat lenses, but the changes are much less rapid and severe. Culture of monkey lenses with xylose provides a model system to extend previous studies of sugar cataractogenesis in rats to a species more closely related to humans.
AB - Lenses exposed to high concentrations of xylose in organ culture produce xylitol, and they lose transparency and exhibit other changes characteristic of cataracts. Most previous studies of this model system for cataractogenesis have employed rat or rabbit lenses, where the activity of the enzyme aldose reductase has been definitely implicated as the initiating factor. Since lenses from this species have much higher aldose reductase activity and have other differences relative to human lenses, the relevance of these findings to the human lens is uncertain. To determine the effects of xylose on the lenses of a primate, lenses from the rhesus monkey (Macaca mulatta) were incubated 24-48 hr in control medium or in TC-199 medium containing 30 mM xylose. Xylose caused a general haziness, focal swelling of epithelial cells, and swollen peripheral fiber cells, but the changes were much less pronounced than in rat lenses under similar conditions. Monkey lenses exposed to 30 mM glucose, galactose or xylose accumulated measurable sorbitol, dulcitol or xylitol, respectively, but the mounts were much lower than in rat lenses, perhaps reflecting the lower aldose reductase and higher sorbitol dehydrogenase activities in monkey lenses. The damage to monkey lenses appeared to be limited to the outer layers. In monkey lenses, xylose caused little, if any, change in membrane transport of choline or α- aminoisobutyrate, but severely depressed synthesis of phosphorylcholine (P- choline), and increased leakage of P-choline into the culture medium, leading to a decrease in the P-choline concentration within 24-48 hr. In summary, xylose- induced damage to monkey lenses in organ culture is qualitatively similar to that seen in rat lenses, but the changes are much less rapid and severe. Culture of monkey lenses with xylose provides a model system to extend previous studies of sugar cataractogenesis in rats to a species more closely related to humans.
KW - Choline transport
KW - Diabetes
KW - Galactose
KW - Human lens
KW - Macaca mulatta
KW - Organ culture
KW - Phosphocholine synthesis
KW - Phosphorylcholine
KW - Rhesus monkey lens
KW - Sugar cataract
KW - Xylose
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U2 - 10.1006/exer.1998.0493
DO - 10.1006/exer.1998.0493
M3 - Article
C2 - 9702179
AN - SCOPUS:0032128136
SN - 0014-4835
VL - 67
SP - 61
EP - 71
JO - Experimental eye research
JF - Experimental eye research
IS - 1
ER -