Effects of enclomiphene and zuclomiphene on basal and gonadotrophin-stimulated progesterone secretion by isolated subpopulations of small and large ovine luteal cells

We examined the effects of enclomiphene and zuclomiphene, aloneand in combination with oestradiol, on basal and gonadotrophin-stimulatedprogesterone secretion by isolated subpopulations of both large(granulosa-lutein) and small (theca-lutein) ovine luteal cells.Isolated large and small luteal cells derived from intact, enucleatedovine corpora lutea were incubated for 48–120 h with orwithout 22R-hydroxycholesterol or pregnenolone (2.5 µM)and a range of enclomiphene, zuclomiphene, and/or oestradiolconcentrations (3–100 µM), both with and withoutovine Iuteinizing hormone (100 ng/ml). Spent media were assayedin duplicate for progesterone content by radioimmunoassay. Enclomiphene,zuclomiphene, and oestradiol exhibited equivalent dose-dependentinhibitory effects on basal and gonadotrophin-stimulated smalland large ovine luteal cell progesterone secretion under allsubstrate conditions. Both cell types became more sensitiveto clomiphene inhibition with increasing time in culture. Incombined treatments, the effects of oestradiol and either enclomipheneor zuclomiphene became additive in longer-term cultures andwere never antagonistic In this model system, (i) clomiphene,like oestradiol, appears to inhibit 3-hydroxysteroid dehy-drogenaseactivity, (ii) both stereoisomers act as oestrogen agonists,(iii) neither demonstrates any anti-oestrogenic properties,and (iv) both large and small luteal cells become more sensitiveto clomiphene inhibition with increasing duration of exposure.     

Pharmacokinetic properties of lutein emulsion after oral administration to rats and effect of food intake on plasma concentration of lutein

Lutein is a carotenoid found mainly in green leafy vegetables and is located in the macula lutea in the human eye. An intake of lutein as food is needed since humans cannot synthesize it de novo. Although lutein has received much attention recently due to its antioxidant activities, little information about the pharmacokinetic properties of lutein is available. Lutein emulsion formulation was used and the pharmacokinetics of lutein emulsion after oral administration to rats was investigated. The bioavailability of lutein using this formulation was calculated to be 5.20%. It was found that a large amount of lutein was accumulated in the intestinal mucosa. The absorption of orally administered compounds in the intestine can be enhanced by interaction with food or food components. Thus, the effect of food intake on the intestinal absorption of lutein was investigated. The plasma concentration of lutein after oral administration of the emulsion formulation was improved significantly by food intake. It is possible that the absorption of lutein in the intestine is improved significantly by some food components. Bile acids may also play important roles in the intestinal absorption of lutein since the absorption of lipophilic compounds such as cholesterol is related to bile acids. The results of these studies should contribute to an improvement of lutein absorption and provide important information for obtaining more effective pharmacological effects of lutein.     

The association between macular pigment optical density and CFH, ARMS2, C2/BF, and C3 genotype

Age-related macular degeneration (AMD) is the most common cause of blindness in older people in developed countries, and risk for this condition may be classified as genetic or environmental, with an interaction between such factors predisposing to this disease. This study investigated the relationship between AMD risk genes, macular pigment optical density (MPOD), which may protect against AMD, and serum concentrations of the macular carotenoids, lutein (L) and zeaxanthin (Z). This was a cross-sectional study of 302 healthy adult subjects. Dietary intake of L and Z was assessed by food frequency questionnaire, and MPOD was measured by customized heterochromatic flicker photometry. We also calculated MPOD Area as the area of MP under the spatial profile curve, to reflect MP across the macula. Serum L and Z were measured by HPLC. Genotyping of tag SNPs in the genes CFH, ARMS2, C3, C2 and BF was undertaken with multiplex polymerase chain reaction (PCR) and primer extension methodology (ABI Snapshot, ABI Warrington UK) on DNA extracted from peripheral blood. The mean ± SD (range) age of the subjects in this study was 48 ± 11 (21–66) years. There was a statistically significant association between CFH genotype and family history of AMD, with subjects having two non-risk CFH haplotypes (n = 35), or one non-risk and one protective CFH haplotype (n = 33), being significantly more likely to have a negative family history of AMD (Pearson Chi square: p = 0.001). There was no significant association between the AMD risk genes investigated and either MPOD (One way ANOVA: p > 0.05) or serum concentrations of L or Z (One way ANOVA: p > 0.05, for both). Subjects who were homozygous for risk alleles of both CFH and ARMS2 (n = 4) had significantly lower MPOD at 0.5° and 1° retinal eccentricity (Independent samples t test: p < 0.05) and lower MPOD Area which approached statistical significance (Independent samples t test: p = 0.058), compared to other subjects (n = 291). In conclusion, this study did not detect an association between individual AMD risk genotypes and the putatively protective MP, or serum concentrations of its constituent carotenoids. However, the combination of homozygous risk alleles at both CFH and ARMS2 loci was associated with significantly lower MPOD centrally, despite comparable serum concentrations of the macular carotenoids. These findings suggest that the maculae of subjects at very high genetic risk of AMD represent a hostile environment for accumulation and/or stabilization of MP.     

EURRECA: EURopean micronutrient RECommendations Aligned. Preparing the way

Background There is increasing evidence that higher intakes of carotenoids could protect against oxidative and light damage in premature infants and may promote other health benefits in both mothers during pregnancy and lactation and in newborn infants. Aim of the study To develop and validate a brief quantitative food frequency questionnaire (FFQ) aimed at assessing lutein and zeaxanthin intake in women. Methods In this cross-sectional study, estimates of lutein and zeaxanthin intake from the FFQ were compared with a 7-day dietary record and with plasma concentrations of these carotenoids. This primary care study was conducted in Pavia, Italy. Subjects were all female volunteers, aged 20–25 years (mean age 22.7 ± 2.1 years), university students. Of the 110 women initially recruited, 87 completed diet questionnaires and donated a blood sample. Dietary intake was assessed by the FFQ by interview and 7-day dietary records chosen as a reference standard, using photographic estimations of portion sizes. Plasma concentrations of lutein and zeaxanthin were measured by HPLC. Pearson’s correlation coefficient and Bland Altman Regression analysis were used. Results Mean dietary lutein and zeaxanthin intakes were 1,107 ± 113 μg/day from the FFQ questionnaire and 1,083 ± 116 μg/day from the 7 day dietary records. The mean difference in intake assessed by the two methods (−24.5 ± 38.3 μg/day) did not differ significantly from zero. Dietary intake of lutein and zeaxanthin measured with the FFQ and plasma nutrient concentration among this sample were significantly correlated (r = 0.76, P < 0.0001). Mean plasma lutein and zeaxanthin concentrations were 0.33 ± 0.09 μmol/l. Conclusions This FFQ could be used to assess lutein and zeaxanthin intake in adult women.     

Beneficial effects of vincamine with thioctic acid and lutein on retinal and optic nerve functions in an opaque media

AIM: To detect whether the combination of vincamine, thioctic acid and lutein will improve the retina and optic nerve functions in cases of an opaque media with an optic nerve and/or a retinal defect or not. METHODS: Totally 2000 patients (2000 eyes) of corneal opacities with defects in the optic nerve or/and the retinal functions were studied. Every patient received three types of drugs: thioctic acid with cyanocobalamine, vincamine, and lutein. The drugs were given daily for 3-12mo according to patient’s responses. Full field flash electroretinogram (ERG) and flash visual evoked potential (VEP) were done before treatment and at 1, 3, 6, and 12mo sequentially. Patients were followed up for 12mo. RESULTS: In the 2000 eyes, 1000 eyes had both moderate optic nerve and retinal function defects; and 840 eyes out of the 1000 improved with the medical treatment. Another 500 eyes out of the 2000 eyes had extinguished retinal function with normal optic nerve function and only 125 eyes of them improved. The 290 out of the 2000 eyes had severe defects in optic nerve with normal retinal function and 130 of them improved. Another 210 eyes have mild optic nerve and retinal function defects and 194 improved. CONCLUSION: The combination of vincamine, thioctic acid with cyanocobalamine, and lutein improved both retina and optic nerve functions mainly in mild and moderate defect than in severe cases.     

Central Retinal Enrichment Supplementation Trials (CREST): Design and Methodology of the CREST Randomized Controlled Trials

Abstract

Purpose: The Central Retinal Enrichment Supplementation Trials (CREST) aim to investigate the potential impact of macular pigment (MP) enrichment, following supplementation with a formulation containing 10?mg lutein (L), 2?mg zeaxanthin (Z) and 10?mg meso-zeaxanthin (MZ), on visual function in normal subjects (Trial 1) and in subjects with early age-related macular degeneration (AMD; Trial 2).

Methods: CREST is a single center, double-blind, randomized clinical trial. Trial 1 (12-month follow-up) subjects are randomly assigned to a formulation containing 10?mg?L, 10?mg MZ and 2?mg Z (n?=?60) or placebo (n?=?60). Trial 2 (24-month follow-up) subjects are randomly assigned to a formulation containing 10?mg?L, 10?mg MZ, 2?mg Z plus 500?mg vitamin C, 400?IU vitamin E, 25?mg zinc and 2?mg copper (Intervention A; n?=?75) or 10?mg?L and 2?mg Z plus 500?mg vitamin C, 400?IU vitamin E, 25?mg zinc and 2?mg copper (Intervention B; n?=?75). Contrast sensitivity (CS) at 6 cycles per degree represents the primary outcome measure in each trial. Secondary outcomes include: CS at other spatial frequencies, MP, best-corrected visual acuity, glare disability, photostress recovery, light scatter, cognitive function, foveal architecture, serum carotenoid concentrations, and subjective visual function. For Trial 2, AMD morphology, reading speed and reading acuity are also being recorded.

Conclusions: CREST is the first study to investigate the impact of supplementation with all three macular carotenoids in the context of a large, double-blind, randomized clinical trial.     

叶黄素干预对长期荧屏光暴露者视功能的影响

目的研究叶黄素干预对长期荧屏光暴露者视功能的影响。方法采用双盲随机空白对照研究,将37名22～30岁长期荧屏光暴露者随机分为低剂量组、高剂量组和安慰剂组,分别每天给予6mg叶黄素、12mg叶黄素及安慰剂,连续干预12w。在干预前及干预后12w时,测定血清叶黄素浓度,并检测泪膜破裂时间,临界闪烁融合频率,明视持久度,视觉反应时等视功能指标。结果叶黄素干预后,高剂量组和低剂量组血清叶黄素(μmol/L)水平分别由0.328±0.120和0.356±0.117上升至0.733±0.354和0.607±0.176。高剂量组左眼泪膜破裂时间较干预前显著延长,明视持久度得到显著改善,平均简单反应时较干预前明显缩短;干预后临界闪烁融合频率、辨别反应时和选择反应时无明显变化。结论叶黄素干预对长期荧屏光暴露者泪膜破裂时间、明视持久度及简单反应时有明显改善作用。     

The selective retention of lutein, meso-zeaxanthin and zeaxanthin in the retina of chicks fed a xanthophyll-free diet

Lutein and zeaxanthin are pigmented oxygenated carotenoids, or xanthophylls, derived from plants and concentrated in the retina of primates and birds. We investigated the transport, distribution and depletion of lutein and zeaxanthin in the plasma and tissues of newly hatched chicks fed xanthophyll-free diets. One-day-old Leghorn chicks were randomly divided into two groups. A control group was fed a diet containing lutein and zeaxanthin (5.2 and 1.7 mg/kg diet, respectively) for 28 days. An experimental group was fed a diet containing no lutein and zeaxanthin for 28 days. Plasma and tissues were analyzed for lutein and zeaxanthin at 28 days (control) and on days 1, 14 and 28 (experimental). At hatching, lutein and zeaxanthin were the predominant carotenoids present in the blood and tissues. As indicated by their similar mass contents, there was complete transfer of these carotenoids from egg yolk to chick. Lutein and zeaxanthin concentrations in the plasma and tissues of chicks fed the xanthophyll-free diet decreased rapidly to almost zero (with a depletion time of seven days [t(1/2)]). In contrast, the retina retained its initial concentrations of lutein and zeaxanthin similar to the control group. meso-Zeaxanthin and cis-zeaxanthin were identified only in the retina. The retina concentrated zeaxanthin over lutein. Lutein and zeaxanthin were selectively retained in the retinas of chicks fed a xanthophyll-free diet. In contrast, the plasma and other tissues lost up to 90% of their original content of xanthophylls. These data emphasize the relative stability of lutein and zeaxanthin in the cone-rich retina where they are present as esters in oil droplets. The tissue depletion suggests the need for a regular dietary intake of lutein and zeaxanthin because of rapid depletion in the body. It is clear that these xanthophylls may have an essential role in the cone-rich retina of the chick as evidenced by their selective retention.     

Nutritional antioxidants and age-related cataract and maculopathy

Loss of vision is the second greatest, next to death, fear among the elderly. Age-related cataract (ARC) and maculopathy (ARM) are two major causes of blindness worldwide. There are several important reasons to study relationships between risk for ARC/ARM and nutrition: (1) because it is likely that the same nutritional practices that are associated with prolonged eye function will also be associated with delayed age-related compromises to other organs, and perhaps, aging in general, (2) surgical resources are insufficient to provide economic and safe surgeries for cataract and do not provide a cure for ARM, and (3) there will be considerable financial savings and improvements in quality of life if health rather than old age is extended, particularly given the rapidly growing elderly segment of our population. It is clear that oxidative stress is associated with compromises to the lens and retina. Recent literature indicates that antioxidants may ameliorate the risk for ARC and ARM. Given the association between oxidative damage and age-related eye debilities, it is not surprising that over 70 studies have attempted to relate antioxidant intake to risk for ARC and ARM. This article will review epidemiological literature about ARC and ARM with emphasis on roles for vitamins C and E and carotenoids. Since glycation and glycoxidation are major molecular insults which involve an oxidative stress component, we also review new literature that relates dietary carbohydrate intake to risk for ARC and ARM. To evaluate dietary effects as a whole, several studies have tried to relate dietary patterns to risk for ARC. We will also give some attention to this emerging research. While data from the observational studies generally support a protective role for antioxidants in foods or supplements, results from intervention trials are less encouraging with respect to limiting risk for ARC/ARM prevalence or progress through antioxidant supplementations, or maintaining higher levels of antioxidants either in diet or blood. Without more information it is difficult to parse these results. It would be worthwhile to determine why the various types of studies are not yielding similar results. However, there are many common insults and mechanistic compromises that are associated with aging, and proper nutrition early in life may address some of these compromises and provide for extended youthful function later in life. Indeed, proper nutrition, possibly including use of antioxidant supplements for the nutritionally impoverished, along with healthy life styles may provide the least costly and most practical means to delay ARC and ARM. Further studies should be devoted to identifying the most effective strategy to prevent or delay the development and progress of ARC/ARM. The efforts should include identifying the right nutrient(s), defining useful levels of the nutrient(s), and determining the age when the supplementation should begin.     

Dietary lutein, zeaxanthin, and fats and the progression of age-related macular degeneration

BACKGROUND: To estimate the effect of dietary intake of lutein and zeaxanthin (L/Z) and fats on the progression of age-related macular degeneration (AMD). METHODS: Two hundred and fifty-four subjects identified with early age-related macular degeneration (AMD) were re-examined to determine 7-year AMD progression. Intakes of L/Z and fatty acids were estimated from food frequency questionnaires. Progression was defined by 3 different definitions, 2 quantitative and 1 qualitative, which varied in the stringency of the change required for the AMD to be deemed to have progressed. Covariates included age, smoking, AMD family history, source study, and follow-up duration. RESULTS: Energy-adjusted L/Z intake as a continuous variable was associated with AMD progression in the worse affected eye when defined by the most stringent criterion (odds ratio [OR] = 2.65, 95% confidence interval [CI] 1.13-6.22, p = 0.02). Similar associations were observed for the 2 other progression definitions (p = 0.18 and p = 0.13). Energy-adjusted omega-3 fatty acid intake modelled as a quintile median was associated with AMD progression only in the side-by-side assessment (OR = 2.56, 95% CI 1.11-5.91, p = 0.03), with borderline significance in the other 2 definitions (p = 0.05 and p = 0.08). No association of AMD progression was observed with the intake of either total fat or other subgroups: saturated, polyunsaturated, or monounsaturated fats; trans fatty acids; or omega-6 fatty acids. INTERPRETATION: The findings of the study are counterintuitive, suggesting that increased intakes of dietary L/Z and omega-3 fatty acids are associated with progression of AMD. These results may indicate that too much of a good thing might be harmful. It is possible that in this study participants adopted a more healthy diet, having been aware of their AMD status at the beginning of the study. This healthy diet was then reflected in the dietary questionnaire completed at the end of study. However, this explanation may not adequately explain why those whose AMD had progressed, on the basis of fundus signs and not symptoms such as visual acuity decline, adopted a healthier lifestyle more aggressively than those without progression.