Optic Nerve Changes in Manganese-deficient Rats

Gong, Huaqing; Amemiya, Tsugio

doi:10.1006/exer.1998.0602

Cited by 17 publications

(9 citation statements)

References 32 publications

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“…Symptoms of overt Mn deficiency in animals or humans have only been reported when diets are severely constrained, such as with confined farm or laboratory animals fed controlled rations low in Mn content. Laboratory and farm animals fed Mn-deficient diets exhibit structural abnormalities, adverse reproductive and fertility effects, glucose intolerance, ataxia, and hearing or vision deficits [103][104][105][106][107]. In humans, Mn deficiency has never been noted among people consuming ordinary diets; it has only manifested after extended periods of controlled experimental diets with very low Mn content or years of total parenteral nutrition (TPN) without…”

Section: Manganese Deficiency Is Highly Unlikely With Either Exclusivmentioning

confidence: 99%

Estimating daily intakes of manganese due to breast milk, infant formulas, or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds

Mitchell¹,

Frisbie

Roudeau

et al. 2020

Preprint

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Laboratories provided no input in choosing the subject matter of this project, the hypotheses that were tested, the method of analysis, the research findings, the decision to publish, or the manner of disseminating the results. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Highlights1. Mn deficiency is unlikely with exclusive breast milk or infant formula feeding.2. Breast milk Mn mean intake is 1.2 µg/kg/day (3 weeks)-0.16 µg/kg/day (18 months).3. Formula Mn intake range is 130 µg/kg/day (3 weeks)-4.8 µg/kg/day (18 months). 4. Formula products reconstituted with 250 µg Mn/L water may exceed 140 µg Mn/kg/day. 5. Formula products may surpass regulatory tolerable daily intake levels for Mn. Abstract BackgroundAlthough manganese (Mn) is an essential nutrient, recent research has revealed that excess Mn in early childhood may have adverse effects on neurodevelopment. MethodsWe estimated daily total Mn intake due to breast milk at average body weights by reviewing reported concentrations of breast milk Mn and measurements of body weight and breast milk intake at 3 weeks, 4.25 months, 7 months, and 18 months. We compared these figures to the Mn content measured in 44 infant, follow-up, and toddler formulas purchased in the United States and France. We calculated Mn content of formula products made with ultra-trace elemental analysis grade water (0 µg Mn/L) and with water containing 250 µg Mn/L, a concentration which is relatively high but less than the World Health Organization Health-based value of 400 µg Mn/L or the United States Environmental Protection Agency Health Advisory of 350 µg Mn/L. ResultsEstimated mean daily Mn intake from breast milk ranged from 1.2 µg Mn/kg/day (3 weeks) to 0.16 µg Mn/kg/day (18 months), with the highest intakes at the youngest age stage we considered, 3 weeks. Estimated daily Mn intake from formula products reconstituted with 0 µg Mn/L water ranged from 130 µg Mn/kg/day (3 weeks) to 4.8 µg Mn/kg/day (18 months) with the highest intakes at 3 weeks. Formula products provided 28 to 520 times greater than the mean daily intake of Mn from breast milk for the 4 age stages that we considered. Estimated daily Mn intake from formula products reconstituted with water containing 250 µg Mn/L ranged from 12 µg Mn/kg/day to 170 µg Mn/kg/day, which exceeds the United States Environmental Protection Agency Reference Dose of 140 µg Mn/kg/day for adults. ConclusionsMn deficiency is highly unlikely with exclusive breast milk or infant formula feeding, but established tolerable daily intake levels for Mn may be surpassed by some of these products when following labeled instructions.

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Section: Manganese Deficiency Is Highly Unlikely With Either Exclusivmentioning

confidence: 99%

Estimating daily intakes of manganese due to breast milk, infant formulas, or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds

Mitchell¹,

Frisbie

Roudeau

et al. 2020

Preprint

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“…Several studies of trace elements have shown that deficiencies of Zn, Cu and Mn cause demyelination or destruction of the optic nerve fibers as was found in the present study of Mg deficiency [10][11][12]. It is assumed that myelin lamellae composed of lipid membranes are oxidized and destroyed by Zn, Cu or Mn deficiency because these trace elements are present in superoxide dismutase, which prevents oxidation of lipid membranes.…”

Section: Discussionmentioning

confidence: 50%

“…The axons in a 600-Ìm 2 field in the central part of the optic nerve were counted in electron micrographs at a magnification of !2,000 as described previously [12]. The diameter of a myelinated axon was measured by the method of Trapp and Bernsohn [15].…”

Section: Electron Microscopymentioning

confidence: 99%

Ultrastructure of the Optic Nerve in Magnesium-Deficient Rats

Gong

Takami²,

Amemiya³

2003

Ophthalmic Res

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Purpose: The ultrastructure of the optic nerves in magnesium (Mg)-deficient rats was studied to elucidate the function of Mg. Methods: After delivery, mother Wistar Kyoto rats were fed a low-Mg diet containing 0.1 mg Mg/100 g diet with all other nutrients and distilled and deionized water. Infant rats were suckled by their mothers for 21 days and then fed the same Mg-deficient diet. Control mother rats were fed commercial rat pellets containing 24 mg Mg/100 g diet and all other nutrients. The optic nerves were examined by electron microscopy at 6 weeks of age. Results: In the Mg-deficient rats, serum Mg levels were significantly lower and calcium levels higher than in the control rats. Ultrastructural findings were: significantly fewer myelinated axons and significantly thinner myelin sheaths in the Mg-deficient rats than in the control and pair-fed controls, and more numerous unmyelinated axons. There were multifocal areas of destruction and necrosis in the optic nerve of Mg-deficient rats. Conclusions: This study suggests that the optic nerve needs Mg for the development and maintenance of its cell structure.

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“…Morphometric studies of the optical nerve of undernourished mice 25 showed that proteic replacement promoted recovery from the deficit of myelinic fibers found in those mice. On the other hand, the replacement of some oligo-elements, such as manganese 26 and zinc, 27 did not restore the myelin cover, and axonal degeneration of the nerve continued to occur.…”

Section: Introductionmentioning

confidence: 97%

Early iron deficiency produces persistent damage to visual tracts in Wistar rats

Demaman

Homem

Lachat

2008

Nutritional Neuroscience

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In this study, morphological changes in the optic nerve were determined by light microscopy in Wistar rats on an iron-deficient diet for 32 days or for 21 days followed by 10 days on an iron-recovery diet. The morphometric findings showed significantly fewer blood vessels and oligodendrocytes in the iron-deficient rats and iron-recovery rats than in the control group, as well as more astrocytes in the iron-recovery rats. Serum iron levels of the iron-deficient rats were significantly lower than those of the controls. On the other hand, iron-recovery rats had normal serum iron levels, but no change in the abnormal morphology of the myelinated axons and morphometric parameters. Our data indicate that iron is necessary for maintenance of the optic nerve cell structure, and morphological damage from iron-deficiency is not easily reverted by iron reposition.

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Optic Nerve Changes in Manganese-deficient Rats

Cited by 17 publications

References 32 publications

Estimating daily intakes of manganese due to breast milk, infant formulas, or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds

Estimating daily intakes of manganese due to breast milk, infant formulas, or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds

Ultrastructure of the Optic Nerve in Magnesium-Deficient Rats

Early iron deficiency produces persistent damage to visual tracts in Wistar rats

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