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Biomedical subjects

Martha Neuringer

Publications and source records attributed to Martha Neuringer.

12 recordsLinked to original sources
PubMed2005

Effect of optimal dietary therapy upon visual function in children with long-chain 3-hydroxyacyl CoA dehydrogenase and trifunctional protein deficiency.

The objective of this prospective cohort study was to determine if dietary therapy including docosahexaenoic acid (DHA; C22:6omega-3) supplementation prevents the progression of the severe chorioretinopathy that develops in children with long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) or trifunctional protein (TFP) deficiency. Physical, biochemical, and ophthalmological evaluations, including electroretinogram (ERG) and visual acuity by evoked potential (VEP), were performed at baseline and annually following the initiation of 65-130 mg/day DHA supplementation and continued treatment with a low-fat diet. Fourteen children with LCHAD or TFP deficiency, 1-12 years of age at enrollment, were followed for 2-5 years. Three subjects with TFP beta-subunit mutations had normal appearance of the posterior pole of the ocular fundi at enrollment and no changes over the course of the study. Eleven subjects who were homozygote and heterozygote for the common mutation, c.1528G>C, had no change to severe progression of atrophy of the choroid and retina with time. Of these, four subjects had marked to severe chorioretinopathy associated with high levels of plasma hydroxyacylcarnitines and decreased color, night and/or central vision during the study. The plasma level of long-chain 3-hydroxyacylcarnitines, metabolites that accumulate as a result of LCHAD and TFP deficiency, was found to be negatively correlated with maximum ERG amplitude (Rmax) (p=0.0038, R2=0.62). In addition, subjects with sustained low plasma long-chain 3-hydroxyacylcarnitines maintained higher ERG amplitudes with time compared to subjects with chronically high 3-hydroxyacylcarnitines. Visual acuity, as determined with the VEP, appeared to increase with time on DHA supplementation (p=0.051) and there was a trend for a positive correlation with plasma DHA concentrations (p=0.075, R2=0.31). Thus, optimal dietary therapy as indicated by low plasma 3-hydroxyacylcarnitine and high plasma DHA concentrations was associated with retention of retinal function and visual acuity in children with LCHAD or TFP deficiency.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed2005

Nutritional manipulation of primate retinas. IV. Effects of n--3 fatty acids, lutein, and zeaxanthin on S-cones and rods in the foveal region.

Lutein and zeaxanthin are xanthophylls selectively accumulated by primate retinas that may protect the macula from age-related macular degeneration. In this project, we manipulated n-3 fatty acids, lutein and/or zeaxanthin levels in the diet and studied their possible outcome on S-cone and rod cell density in the foveal region. Rhesus monkeys (7-16 year, n=17) were fed from birth xanthophyll-free semipurified diets with either adequate or low n-3 fatty acids. Five monkeys were supplemented with lutein and six with zeaxanthin for 6-24 months, while six remained xanthophyll-free until sacrifice. Retinas were embedded in methacrylate and serial 2 microm sections were cut along the vertical meridian. Rod nuclei, and immuno-labelled outer segments of S-cones and rods, were reconstructed and counted in an 8 microm strip. The density profiles were compared with data from control monkeys (n=7) fed a standard laboratory diet. S-cone density profiles were symmetrical along the vertical meridian and the densities decreased rapidly with retinal eccentricity. Rod densities were higher in the superior region than the inferior region in most of the control and experimental animals. Unlike the significant effects observed for retinal pigment epithelial cells of these same monkeys (Leung, I.Y-F., Sandstrom, M.M., Zucker, C.L., Neuringer, M., Snodderly, D.M., 2004. Nutritional manipulation of primate retinas. II. Effects of age, n-3 fatty acids, lutein, and zeaxanthin on retinal pigment epithelium. Invest. Ophthalmol. Vis. Sci. 45, 3244-3256), neither xanthophyll supplementation nor low dietary n-3 fatty acids produced consistent effects on S-cone or rod density profiles of the experimental animals. However, monkeys low in n-3 fatty acids had increased variability of S-cone density in the fovea and low density of foveal rod outer segments. The high variability suggests that the photoreceptors of some animals were resistant to the nutritional manipulations, while others may have been affected. Thus, the photoreceptors appear less sensitive than the retinal pigment epithelium to these nutritional manipulations. However, it is possible that more consistent effects would emerge at a later age or after exposure to stressors such as high light levels.

Animal Nutritional Physiological Phenomena↗
PubMed2005

Nutritional manipulation of primate retinas, III: Effects of lutein or zeaxanthin supplementation on adipose tissue and retina of xanthophyll-free monkeys.

PURPOSE: Macular pigment (MP) is composed of the xanthophylls lutein (L) and zeaxanthin (Z) and may help to prevent age-related macular degeneration or retard its progression. In this study the effects of L or Z supplementation on carotenoid levels was examined in serum, adipose tissue, and retina in rhesus monkeys with no previous intake of xanthophylls. METHODS: From birth to 7 to 16 years of age, 18 rhesus monkeys were fed semipurified diets containing all essential nutrients but no xanthophylls. Six were supplemented with pure L and 6 with pure Z at 3.9 micromol/kg per day for 24 to 101 weeks. At baseline and at 4- to 12-week intervals, carotenoids in adipose tissue were measured by HPLC. At study completion, carotenoids in serum and retina (central 4 mm, 8-mm annulus, and the periphery) were determined. Results were compared with data from control monkeys fed a standard laboratory diet. RESULTS: Monkeys fed xanthophyll-free diets had no L or Z in serum or tissues. After L or Z supplementation, serum and adipose tissue concentrations significantly increased in the supplemented groups. Both L and 3R,3'S-Z (RSZ or meso-Z, not present in the diet) were incorporated into retinas of monkeys supplemented with L, with RSZ present only in the macula (central 4 mm). All-trans Z, but no RSZ, accumulated in retinas of monkeys supplemented with Z. CONCLUSIONS: L is the precursor of RSZ, a major component of macular pigment. Xanthophyll-free monkeys can accumulate retinal xanthophylls and provide a valuable model for examining their uptake and conversion.

Adipose Tissue↗
PubMed2005

Can prenatal N-3 fatty acid deficiency be completely reversed after birth? Effects on retinal and brain biochemistry and visual function in rhesus monkeys.

Our previous studies of rhesus monkeys showed that combined prenatal and postnatal n-3 fatty acid deficiency resulted in reduced visual acuity, abnormal retinal function, and low retina and brain docosahexaenoic acid content. We now report effects of n-3 fatty acid deficiency during intrauterine development only. Rhesus infants, born to mothers fed an n-3 fatty acid deficient diet throughout pregnancy, were repleted with a diet high in alpha-linolenic acid from birth to 3 y. Fatty acid composition was determined for plasma and erythrocytes at several time points, for prefrontal cerebral cortex biopsies at 15, 30, 45, and 60 wk, and for cerebral cortex and retina at 3 y. Visual acuity was determined behaviorally at 4, 8, and 12 postnatal weeks, and the electroretinogram was recorded at 3-4 mo. Total n-3 fatty acids were reduced by 70-90% in plasma, erythrocytes, and tissues at birth but recovered to control values within 4 wk in plasma, 8 wk in erythrocytes, and 15 wk in cerebral cortex. At 3 y, fatty acid composition was normal in brain phospholipids, but in the retina DHA recovery was incomplete (84% of controls). Visual acuity thresholds did not differ from those of control infants from mothers fed a high linolenic acid diet. However, the repleted group had lower amplitudes of cone and rod ERG a-waves. These data suggest that restriction of n-3 fatty acid intake during the prenatal period may have long-term effects on retinal fatty acid composition and function.

Animals↗
PubMed2004

Nutritional manipulation of primate retinas, II: effects of age, n-3 fatty acids, lutein, and zeaxanthin on retinal pigment epithelium.

PURPOSE: To study the effects of age and of n-3 fatty acids, lutein, and zeaxanthin on the retinal pigment epithelium (RPE). METHODS: Rhesus monkeys (age range, 7-17 years; n = 18) were fed xanthophyll-free semipurified diets from birth. The diets had either low or adequate amounts of n-3 fatty acids. Six monkeys remained xanthophyll-free until death. Six received supplements of pure lutein and six of pure zeaxanthin for 6 to 24 months. The central retina was serially sectioned, and the number of RPE cells were counted in an 8-microm strip along the vertical meridian. Cell counts were compared with data from control monkeys (n = 15) fed a standard laboratory diet. RESULTS: Foveal and parafoveal RPE cell densities increased with age. Xanthophyll-free monkeys had a dip in the RPE cell density profile at the foveal center, rather than the normal peak. After supplementation with xanthophylls, the RPE profile of animals low in n-3 fatty acids no longer had a dip at the foveal center but became asymmetric, with higher densities in the inferior retina. In animals with adequate n-3 fatty acid levels, xanthophyll supplementation did not restore the foveal peak, and resulted in an asymmetric profile with higher densities in the superior retina. CONCLUSIONS: RPE cells are sensitive to the absence of macular pigment. Supplemental xanthophylls interact with n-3 fatty acid levels to produce asymmetries in the RPE profile. Xanthophylls and n-3 fatty acids are essential for the development and/or maintenance of a normal distribution of RPE cells.

Aging↗
PubMed2004

Nutritional manipulation of primate retinas, I: effects of lutein or zeaxanthin supplements on serum and macular pigment in xanthophyll-free rhesus monkeys.

PURPOSE: The xanthophylls lutein (L) and zeaxanthin (Z) are the primary components of macular pigment (MP) and may protect the macula from age-related degeneration (AMD). In this study, L or Z was fed to rhesus monkeys reared on xanthophyll-free diets to follow the accumulation of serum carotenoids and MP over time. METHODS: Eighteen rhesus monkeys were fed xanthophyll-free semipurified diets from birth until 7 to 16 years. The diets of six were then supplemented with pure L and six with pure Z at 3.9 micromol/kg per day (2.2 mg/kg per day) for 24 to 56 weeks. At baseline and 4- to 12-week intervals during supplementation, serum carotenoids were measured by HPLC, and MP density was estimated by two-wavelength reflectometry. Serum carotenoids and MP were also measured in monkeys fed a stock diet. RESULTS: Monkeys fed xanthophyll-free diets had no L or Z in serum and no detectable MP. During supplementation, serum L or Z increased rapidly over the first 4 weeks and from 16 weeks onward maintained similar levels, both several times higher than in stock-diet-fed monkeys. The central peak of MP optical density increased to a relatively steady level by 24 to 32 weeks in both L- and Z-fed groups. Rhesus monkeys fed a stock diet had lower blood concentrations of L than those found in humans and other nonhuman primates. CONCLUSIONS: Rhesus monkeys respond to either dietary L or Z supplementation with increases in serum xanthophylls and MP, even after life-long xanthophyll deficiency. These animals provide a potential model to study mechanisms of protection from AMD.

Animals↗
PubMed2003

Selective changes of docosahexaenoic acid-containing phospholipid molecular species in monkey testis during puberty.

Puberty has a profound effect upon the biochemical composition of the testis. We previously demonstrated that puberty was accompanied by great increases in the content of docosahexaenoic acid (DHA; 22:6 n-3) and dihomogamma-linoleic acid (20:3 n-6) and decreases in arachidonic acid (AA; 20:4 n-6) in the phospholipids of testis. In this report, we analyze the composition of the phospholipid molecular species of the ethanolamine and choline glycerophospholipids in the testis of prepubertal (2 years old) and young adult (7-8 years old) monkeys, There was an increase in the DHA species and a decrease in arachidonic species. Interestingly, with few exceptions, among the three molecules with DHA or AA at the sn-2 position, only 16:0-22:6 and 18:0-20:4 changed selectively in opposite directions for both ethanolamine and choline glycerophospholipids. In contrast, there was no such selectivity seen in molecular species containing dihomogamma-linoleic acid or linoleic acid at the sn-2 position. All three dihomogamma-linoleic acid species increased and all three linoleic acid species decreased during puberty. In summary, at puberty, i.e., the onset of spermatogenesis, there are selective changes in the phospholipid molecular species, particularly those containing DHA and AA. These changes suggest a specific functional role of DHA-containing molecular species in the lipid bilayer membranes of sperm cells. A possible link between the composition of DHA-phospholipid molecular species and cellular function is discussed.

Animals↗
PubMed2003

Growth and development of premature infants fed predominantly human milk, predominantly premature infant formula, or a combination of human milk and premature formula.

BACKGROUND: In a recent meta-analysis, human milk feeding of low birth-weight (LBW) infants was associated with a 5.2 point improvement in IQ tests. However, in the studies in this meta-analysis, feeding regimens were used (unfortified human milk, term formula) that no longer represent recommended practice. OBJECTIVE: To compare the growth, in-hospital feeding tolerance, morbidity, and development (cognitive, motor, visual, and language) of LBW infants fed different amounts of human milk until term chronologic age (CA) with those of LBW infants fed nutrient-enriched formulas from first enteral feeding. METHODS: The data in this study were collected in a previous randomized controlled trial assessing the benefit of supplementing nutrient-enriched formulas for LBW infants with arachidonic acid and docosahexaenoic acid. Infants (n = 463, birth weight, 750-1,800 g) were enrolled from nurseries located in Chile, the United Kingdom, and the United States. If human milk was fed before hospital discharge, it was fortified (3,050-3,300 kJ/L, 22-24 kcal/oz). As infants were weaned from human milk, they were fed nutrient-enriched formula with or without arachidonic and docosahexaenoic acids (3,300 kJ/L before term, 3,050 kJ/L thereafter) until 12 months CA. Formula fed infants were given nutrient-enriched formula with or without added arachidonic and docosahexaenoic acids (3,300 kJ/L to term, 3,050 kJ/L thereafter) until 12 months CA. For the purposes of this evaluation, infants were categorized into four mutually exclusive feeding groups: 1) predominantly human milk fed until term CA (PHM-T, n = 43); 2) >/= 50% energy from human milk before hospital discharge (>/= 50% HM, n = 98); 3) < 50% of energy from human milk before hospital discharge (< 50% HM, n = 203); or 4) predominantly formula fed until term CA (PFF-T, n = 119). RESULTS: PFF-T infants weighed approximately 500 g more at term CA than did PHM-T infants. This absolute difference persisted until 6 months CA. PFF-T infants were also longer (1.0-1.5 cm) and had larger head circumferences (0.3-1.1 cm) than both PHM-T and >/= 50% HM infants at term CA. There was a positive association between duration of human milk feeding and the Bayley Mental Index at 12 months CA (P = 0.032 full and P = 0.073 reduced, statistical models) after controlling for the confounding variables of home environment and maternal intelligence. Infants with chronic lung disease fed >/= 50% HM until term CA (n = 22) had a mean Bayley Motor Index about 11 points higher at 12 months CA compared with infants PFF-T (n = 24, P = 0.033 full model). CONCLUSION: Our data suggest that, despite a slower early growth rate, human milk fed LBW infants have development at least comparable to that of infants fed nutrient-enriched formula. Exploratory analysis suggests that some subgroups of human milk fed LBW infants may have enhanced development, although this needs to be confirmed in future studies.

Adult↗
PubMed2003

Visual, cognitive, and language assessments at 39 months: a follow-up study of children fed formulas containing long-chain polyunsaturated fatty acids to 1 year of age.

OBJECTIVE: Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are long-chain polyunsaturated fatty acids found in breast milk and recently added to infant formulas. Their importance in infant nutrition was recognized by the rapid accretion of these fatty acids in the brain during the first postnatal year, reports of enhanced intellectual development in breastfed children, and recognition of the physiologic importance of DHA in visual and neural systems from studies in animal models. These considerations led to clinical trials to evaluate whether infant formulas that are supplemented with DHA or both DHA and ARA would enhance visual and cognitive development or whether conversion of linoleic acid and alpha-linolenic acid, the essential fatty acid precursors of ARA and DHA, respectively, at the levels found in infant formulas is sufficient to support adequately visual and cognitive development. Visual and cognitive development were not different with supplementation in some studies, whereas other studies reported benefits of adding DHA or both DHA and ARA to formula. One of the first trials with term infants that were fed formula supplemented with DHA or both DHA and ARA evaluated growth, visual acuity (Visual Evoked Potential; Acuity Card Procedure), mental and motor development (Bayley Scales of Infant Development), and early language development (MacArthur Communicative Developmental Inventories). Growth, visual acuity, and mental and motor development were not different among the 3 formula groups or between the breastfed and formula-fed infants in the first year of life. At 14 months of age, infants who were fed the formula with DHA but no ARA had lower vocabulary production and comprehension scores than infants who were fed the unsupplemented control formula or who were breastfed, respectively. The present follow-up study evaluated IQ, receptive and expressive vocabulary, visual-motor function, and visual acuity of children from the original trial when they reached 39 months of age. METHODS: Infants were randomized within 1 week after birth and fed a control formula (n = 65), one containing DHA (n = 65), or one containing both ARA and DHA (n = 66) to 1 year of age. A comparison group (n = 80) was exclusively breastfed for at least 3 months after which the infants continued to be exclusively breastfed or were supplemented with and/or weaned to infant formula. At 39 months, standard tests of IQ (Stanford Binet IQ), receptive vocabulary (Peabody Picture Vocabulary Test-Revised), expressive vocabulary (mean length of utterance), visual-motor function (Beery Visual-Motor Index), and visual acuity (Acuity Card Procedure) were administered. Growth, red blood cell fatty acid levels, and morbidity also were evaluated. RESULTS: Results were analyzed using analysis of variance or linear regression models. The regression model for IQ, receptive and expressive language, and the visual-motor index controlled for site, birth weight, sex, maternal education, maternal age, and the child's age at testing. The regression model for visual acuity controlled for site only. A variable selection model also identified which of 22 potentially prognostic variables among different categories (feeding groups, the child and family demographics, indicators of illness since birth, and environment) were most influential for IQ and expressive vocabulary. A total of 157 (80%) of the 197 infants studied at 12 months participated in this follow-up study. Characteristics of the families were representative of US families with children up to 5 years of age, and there were no differences in the demographic or family characteristics among the randomized formula groups. As expected, the formula and breastfed groups differed in ethnicity, marital status, parental education, and the prevalence of smoking. Sex, ethnicity, gestational age at birth, and birth weight for those who participated at 39 months did not differ from those who did not. The 12-month Bayley mental and motor scores and 14-month vocabulary scores of the children who participated also were were not different from those who did not. At 39 months, IQ, receptive and expressive language, visual-motor function, and visual acuity were not different among the 3 randomized formula groups or between the breastfed and formula groups. The adjusted means for the control, ARA+DHA, DHA, and breastfed groups were as follows: IQ scores, 104, 101, 100, 106; Peabody Picture Vocabulary Test, 99.2, 97.2, 95.1, 97.4; mean length of utterance, 3.64, 3.75, 3.93, 4.08; the visual-motor index, 2.26, 2.24, 2.05, 2.40; and visual acuity (cycles/degree), 30.4, 27.9, 27.5, 28.6, respectively. IQ was positively associated with female sex and maternal education and negatively associated with the number of siblings and exposure to cigarette smoking in utero and/or postnatally. Expressive language also was positively associated with maternal education and negatively associated with the average hours in child care per week and hospitalizations since birth but only when the breastfed group was included in the analysis. The associations between maternal education and child IQ scores are consistent with previous reports as are the associations between prenatal exposure to cigarette smoke and IQ and early language development. Approximately one third of the variance for IQ was explained by sex, maternal education, the number of siblings, and exposure to cigarette smoke. Growth achievement, red blood cell fatty acid levels, and morbidity did not differ among groups. CONCLUSIONS: We reported previously that infants who were fed an unsupplemented formula or one with DHA or with both DHA and ARA through 12 months or were breastfed showed no differences in mental and motor development, but those who were fed DHA without ARA had lower vocabulary scores on a standardized, parent-report instrument at 14 months of age when compared with infants who were fed the unsupplemented formula or who were breastfed. When the infants were reassessed at 39 months using age-appropriate tests of receptive and expressive language as well as IQ, visual-motor function and visual acuity, no differences among the formula groups or between the formula and breastfed groups were found. The 14-month observation thus may have been a transient effect of DHA (without ARA) supplementation on early vocabulary development or may have occurred by chance. The absence of differences in growth achievement adds to the evidence that DHA with or without ARA supports normal growth in full-term infants. In conclusion, adding both DHA and ARA when supplementing infant formulas with long-chain polyunsaturated fatty acids supports visual and cognitive development through 39 months.

Arachidonic Acid↗
PubMed2002

n-3 fatty acid deficiency alters recovery of the rod photoresponse in rhesus monkeys.

PURPOSE: Docosahexaenoic acid (DHA) is the major polyunsaturated fatty acid within rod outer segments. Varying the dietary content of DHA or its precursor, alpha-linolenic acid (ALA), can alter retinal DHA levels. The purpose of the present study was to assess rod phototransduction and recovery in rhesus monkeys raised on diets with different DHA and ALA content. METHODS: Adult rhesus monkeys had consumed from birth a diet low in ALA (0.3%) and known to induce an 80% reduction in retinal DHA. They were compared with groups receiving 8% ALA or 0.6% DHA, both of which support normal retinal DHA levels. Rod recovery was assessed with a double-flash protocol using a-wave saturating test flashes. The recovery of rod-isolated ERG a-wave amplitude was analyzed to determine Tc, the time to initiation of rod recovery, and T50, the time from initiation to 50% of full recovery. Phototransduction was assessed from the fit of a quantitative model to the leading edges of rod-isolated ERG a-waves. ERG a- and b-wave amplitudes and implicit times were also measured. RESULTS: Rod recovery (T50) was delayed by 30% and ERG implicit times by 5% in monkeys in the low ALA group compared with the other groups. There was no significant effect of diet on ERG amplitudes, the time to initiation of rod recovery, or the parameters describing phototransduction. CONCLUSIONS: The results indicate that mechanisms involved in deactivation and rod recovery are selectively altered in monkeys raised on a low-ALA diet whereas, at the flash intensities used, the mechanisms underlying phototransduction remain unaffected.

Animals↗
PubMed2002

Retinal pigment epithelial cell distribution in central retina of rhesus monkeys.

PURPOSE: To determine the cell density profile of the retinal pigment epithelium (RPE) in the central retina and relate it to the distribution of photoreceptors. METHODS: Wholemounts of rhesus monkey (Macaca mulatta) retinas with the choroid removed but the RPE attached were stained with the nuclear stain 4',6-diamidine-2-phenylindole dihydrochloride (DAPI) and imaged with a fluorescence microscope. RPE cell nuclei were counted at the foveal center and at 0.4-mm intervals along the vertical meridian. The number of photoreceptors per RPE cell at each location was estimated by using previously published data on the distribution of rhesus photoreceptors. RESULTS: Data were collected from eight retinas. Mean RPE cell density increased from a relatively stable baseline of approximately 4000 RPE cells/mm(2) beyond 2 mm (10 degrees ) eccentricity to more than 7000 cells/mm(2) at the center of the fovea. The number of cones per RPE cell in the rhesus retina was approximately 20:1 in the foveal center (similar to the human retina) and only approximately 1.5:1 in the parafovea. However, when the rods were included, and the total number of photoreceptors per RPE cell were considered, the ratio of photoreceptors to RPE cells was lower in the fovea than in the remainder of the central retina. CONCLUSIONS: In spite of the high cone density, there is a relatively low number of photoreceptors per RPE cell in the fovea. This may limit the metabolic demands on foveal RPE cells and help to preserve their functions in the face of aging and disease.

Animals↗