Retinyl Palmitate Concentrations Research Articles

Ovariectomy Increases Circulating Retinol-Binding Protein Concentrations Independently of Sex-Dependent Differences in Retinol Concentrations in Rats

BackgroundThere is a sex-dependent difference in blood retinol and RBP concentrations, and plasma RBP is associated with insulin resistance. ObjectivesWe aimed to clarify sex-dependent variations in body concentrations of retinol and RBPs and their association with sex hormones in rats. MethodsPlasma and liver retinol concentrations and hepatic mRNA and plasma concentrations of RBP4 were analyzed in 3- and 8-wk-old male and female Wistar rats before and after sexual maturity (experiment 1) and in orchiectomized male Wistar rats (experiment 2) and ovariectomized female Wistar rats (experiment 3). Furthermore, the mRNA and protein concentrations of RBP4 in adipose tissue were measured in ovariectomized female rats (experiment 3). ResultsThere were no sex-dependent differences in liver retinyl palmitate and retinol concentrations; however, the plasma retinol concentration was significantly higher in male rats than that in female rats after sexual maturity. Furthermore, the plasma retinol concentrations did not differ between the ovariectomized or orchiectomized rats and the control rats. Plasma Rbp4 mRNA concentrations were higher in male rats than those in female rats but not in castrated and control rats, a change consistent with plasma retinol concentration. Plasma RBP4 concentrations were also higher in male rats than those in female rats; however, unlike liver Rbp4 gene expression, plasma RBP4 concentrations were 7-fold higher in the ovariectomized rats than those in the control rats. Moreover, the Rbp4 mRNA concentrations in inguinal white adipose tissue was significantly higher in the ovariectomized rats than those in the control rats and correlated with plasma RBP4 concentrations. ConclusionsHepatic Rbp4 mRNA is higher in male rats through a sex hormone–independent mechanism, which may contribute to sex differences in blood retinol concentrations. Furthermore, ovariectomy leads to an increase in adipose tissue Rbp4 mRNA and blood RBP4 concentrations, which may contribute to insulin resistance in ovariectomized rats and postmenopausal women.

Stability and Applicability of Retinyl Palmitate Loaded Beeswax Microcapsules for Cosmetic Use

In our previous study, retinyl palmitate was successfully encapsulated by melt dispersion using waxes as shell materials. Herein, the objective of the present research is to evaluate the shelf life and kinetic release of the developed microcapsules. The study was conducted by measuring actual loading capacity over a period of time using spectroscopic analysis. The transfer percentage of particles from nonwoven facial wipes to skin-like surfaces was also investigated by simulating the rubbing mechanism with a robotic transfer replicator. Although particles stored as powder form under room temperature showed only eight days of shelf-life, particles stored as a dispersion in a refrigerator maintained 60% of the theoretical loading capacity after one month. The kinetic release profile of the particles in ethanol with shaking at 100 rpm and 37±2°C showed an initial burst in the first half an hour, followed by a sustained release. It also showed that 98% of the retinyl palmitate content released within 4 h. Particles incorporated into wet nonwoven wipes gave approximately 22% transfer to skin-like fabric. Thus, the study shows potentials of delivering skincare properties by means of retinyl palmitate capsule loaded textile substrates.

Contribution of bread and biscuits to vitamin A daily requirement of preschool children in Lagos State, Nigeria

Introduction and aim. Vitamin-A-deficiency is a public health problem among preschool children of Nigeria. Study determined the contribution of bread and biscuits to vitamin A-daily-requirement of preschool children in Lagos-State, Nigeria. Material and methods. A community-based-study using a cross-sectional-design with analytical component was carried out from 2013-2015. Multi-stage-sampling-technique was used to select mothers of preschool-children (n=1599) in 5 Local-Government- Areas of Lagos. Respondents’ socio-demographic information and samples consumption-pattern were collected using validated, food-frequency-questionnaire/dietary recall. Retinyl palmitate content of randomly selected commonly-consumed brands of oven-fresh-bread stored for 5-days and biscuits (30- to 60-days) at prevailing outdoor-market-temperatures were analysed using High-Performance-Liquid-Chromatography. Contribution to preschool children’s vitamin A-daily-requirements were determined. Data were analysed using Student’s t-test and ANOVA at p<0.05. Results. Mean age of preschool children was 31.44±5.28 months. Mean intakes of samples were bread (117.6 ±15.9 g/d) and biscuits (59.8±27.9 g/d). Range of contribution to vitamin-A-daily-requirement of preschool-children was 0-178.4 %. Samples contribution to vitamin A-daily-requirement of pre-school-children were oven-fresh bread (68.3 %); 5 days bread (20.7%); 30-days biscuits (25.0%) and 60-days biscuits (6.8%). Overall contribution to vitamin A-daily-requirement were bread (51.4%) and biscuits (22.4%). Statistically significant difference existed between samples contribution and vitamin-A-daily-requirement of preschool children. Conclusion. Bread and biscuits samples contributed significantly to the vitamin-A-daily-requirement of preschool children.

β-Carotene Bioavailability and Conversion Efficiency Are Significantly Affected by Sex in Rats: First Observation Suggesting a Possible Hormetic Regulation of Vitamin A Metabolism in Female Rats.

To study the effect of variation in dietary vitamin A (VA) content on its hepatic and intestinal metabolism. Adult female and male rats are fed with diets containing 400, 2300, or 9858IU kg-1 VA for 31-33 weeks. VA concentrations are measured in plasma and liver. Bioavailability and intestinal conversion efficiency of β-carotene to VA are assessed by measuring postprandial plasma β-carotene and retinyl palmitate concentrations after force-feeding rats with β-carotene. Expression of genes involved in VA metabolism, together with concentrations of RBP4, BCO1, and SR-BI proteins, are measured in the intestine and liver of female rats. Plasma retinol concentrations are lower and hepatic free retinol concentrations are higher in females than in males. There is no effect of dietary VA content on β-carotene bioavailability and its conversion efficiency, but bioavailability is higher and conversion efficiency is lower in females than in males. The expression of most genes exhibited a U-shaped dose response curve depending on VA intake. β-Carotene bioavailability and conversion efficiency to VA are affected by the sex of rats. Results of gene expression suggest a hormetic regulation of VA metabolism in female rats.

Effects of a high-fat diet and global aryl hydrocarbon receptor deficiency on energy balance and liver retinoid status in male Sprague-Dawley rats

The physiological functions of the aryl hydrocarbon receptor (AHR) are only beginning to unfold. Studies in wildtype and AHR knockout (AHRKO) mice have recently disclosed that AHR activity is required for obesity and steatohepatitis to develop when mice are fed with a high-fat diet (HFD). In addition, a line of AHRKO mouse has been reported to accumulate retinoids in the liver. Whether these are universal manifestations across species related to AHR activity level is not known yet. Therefore, we here subjected wildtype and AHRKO male rats (on Sprague-Dawley background) to HFD feeding coupled with free access to 10% sucrose solution and water; controls received a standard diet and water. Although the HFD-fed rats consumed more energy throughout the 24-week feeding regimen, they did not get overweight. However, relative weights of the brown and epididymal adipose tissues were elevated in HFD-fed rats, while that of the liver was lower in AHRKO than wildtype rats. Moreover, the four groups exhibited diet- or genotype-dependent differences in biochemical variables, some of which suggested marked dissimilarities from AHRKO mice. Expression of pro- and anti-inflammatory genes was induced in livers of HFD-fed AHRKO rats, but histologically they did not differ from others. HFD reduced the hepatic concentrations of retinyl palmitate, 9-cis-4-oxo-13,14-dihydroretinoic acid and (suggestively) retinol, whereas AHR status had no effect. Hence, the background strain/line of AHRKO rat is resistant to diet-induced obesity, and AHR does not modulate this or liver retinoid concentrations. Yet, subtle AHR-dependent differences in energy balance-related factors exist despite similar weight development.

Разработка антиоксидантного комплекса для использования в продуктах с эмульсионной основой

Исследованы антиоксидантные свойства индивидуальных веществ и их смесей, таких как α-токоферол, кверцетин, β-ситостерин, ретинил пальмитат для создания антиоксидантного комплекса, стабилизирующего эмульсионные системы. Для определения антиоксидантной активности оценивали способность индивидуальных соединений и их смесей тормозить реакции термического окисления метилового эфира олеиновой кислоты. Показано, что усиление антиоксидантных свойств бинарной смеси витаминов наблюдается при увеличении концентрации α-токоферола и уменьшении концентрации ретинил пальмитата. Установлен эффект взаимного подавления антиоксидантных свойств смеси ретинил пальмитата с β-ситостерином. Доказано, что значение антиоксидантной активности реакционной смеси, включающей кверцетин в сочетании с витаминами или β-ситостерином, обладает аддитивными свойствами. Для смеси, состоящей из 4-х компонентов: α-токоферол, кверцетин, β-ситостерин, ретинил пальмитат, характерно увеличение антиоксидантных свойств в 2,5 раза при минимальных концентрациях, а при максимальных концентрациях в 1,5 раза. Установлено, что все исследуемые природные соединения обладали антипероксидной активностью, при этом наиболее высокий уровень отмечен у кверцетина, далее у ретинил пальмитата, β-ситостерина и α-токоферола. Показано, что смесь природных антиоксидантов обладала антипероксидной активностью в 1,5 раза выше, чем у кверцетина. На основе полученного уравнения регрессии, адекватно описывающего процесс, реализована программа оптимизации, позволившая сформировать антиоксидантный комплекс, включающий ретинил пальмитат, α-токоферол, β-ситостерин и кверцетин в оптимальных соотношениях. Показано, что антиоксидантная активность комплекса в 1,7 раза превосходила результат этого показателя в смеси, состоящей из 4-х изучаемых компонентов. Разработанный антиоксидантный комплекс рекомендован для использования в составе продуктов с эмульсионной основой

Influencia de palmitato de retinilo en las cinéticas de nucleación y crecimiento en la cristalización batch de la caña de azúcar

The influence of retinyl palmitate (RP) on nucleation and growth kinetics, in the sugarcane fortification process, is analyzed. Batch cooling crystallization experiments using natural and linear profiles were carried out adding different amounts of RP. At each experiment, sugar concentration, crystal mass and crystal size distribution were measured as a function of time. Nucleation and growth rates were determined experimentally and kinetic parameters were determined using power-law type relations. At the end of each experiment, crystals were observed in microscope and morphological changes were analyzed. The results showed that the presence of RP in the fortification process of sugar generated a decrease in both nucleation and growth rates. The decrement was bigger when the initial concentration of RP increased. Moreover, it was observed that fortified crystals suffer morphological changes into their habit.

Distribution of injected fat-soluble vitamins in plasma and tissues of nursery pigs.

ObjectiveThe objective of this experiment was to investigate the effects of fat-soluble vitamin injection on plasma and tissue vitamin status in nursery pigs.MethodsA total of 16 pigs (initial body weight: 7.15±1.1 kg) were allotted to 2 treatments at d 7 post-weaning. Pigs were fed a corn-soybean meal-based basal diet with no supplemental vitamin A and i.m. injected with 300,000 IU of retinyl palmitate, 900 IU of d-α-tocopherol and 30,000 IU of vitamin D3 with control pigs having no vitamin injection. Blood (d 0, 3, 7, and 14 post-injection) and tissue samples (liver, brain, heart, lung, and muscle; d 7 and 14 post-injection) were collected from pigs. Retinyl palmitate, retinol, and α-tocopherol concentrations were analyzed in plasma and tissues, while plasma was assayed for 25-hydroxycholecalciferol (25-OHD3).ResultsPlasma retinol and 25-OHD3 concentrations increased by the vitamin injection from d 3 to 14 post-injection (p<0.05) whereas plasma retinyl palmitate was detected only in the vitamin treatment at d 3 and 7 post-injection (115.51 and 4.97 μg/mL, respectively). Liver retinol, retinyl palmitate, and retinol+retinyl palmitate concentrations increased by retinyl palmitate injection at d 7 and 14 post-injection (p<0.05) whereas those were not detected in the other tissues. The d-α-tocopherol injection increased α-tocopherol concentrations in plasma at d 3 and 7 post-injection (p<0.05) and in liver, heart (p<0.10), and muscle (p<0.05) at d 7 post-injection.ConclusionFat-soluble vitamin injection increased plasma status of α-tocopherol, retinol, retinyl palmitate and 25-OHD3. As plasma levels decreased post-injection, vitamin A level in liver and vitamin E level in muscle, heart and liver increased. The α-tocopherol found in plasma after injection was distributed to various tissues but retinyl palmitate only to the liver.

Characterization of Vitamin A Metabolome in Human Livers With and Without Nonalcoholic Fatty Liver Disease.

Retinoids are essential endogenous compounds involved in regulation of critical biologic processes, including maintenance of metabolic homeostasis in the liver. Much of the knowledge of altered retinoid homeostasis in human disease states is derived from changes in indirect markers such as mRNA expression of retinoid-related genes and circulating concentrations of retinol or its binding protein RBP4. We hypothesized that in the human liver, concentrations of the active retinoid all-trans-retinoic acid (atRA) correlate with the concentrations of retinyl palmitate (RP), the storage form of atRA, retinol, the inactive vitamin A, and the mRNA expression of retinoid-related genes. On the basis of existing knowledge of altered vitamin A homeostasis in metabolic syndrome, we also predicted that in human livers with nonalcoholic fatty liver disease (NAFLD) retinoid concentrations would be decreased. Using novel liquid chromatography-tandem mass spectrometry methods, the hepatic vitamin A metabolome was quantified in normal human livers (n = 50) and 22 livers from donors with NAFLD. The hepatic concentrations of RP, atRA, 13-cisRA, and 4-oxo-atRA were significantly decreased in NAFLD samples in comparison with normal liver samples, whereas retinol levels remained unchanged. The concentrations of atRA were positively correlated with RP and 13-cisRA but not with retinol or the relative mRNA expression of LRAT, ALDH1A1, CYP26A1, RARα, and RARβ An active metabolite of atRA, 4-oxo-atRA was, for the first time, detected in human tissues at comparable concentration with RA isomers, suggesting this retinoid may contribute to retinoid signaling in humans. SIGNIFICANCE STATEMENT: This study shows that in NAFLD liver vitamin A homeostasis is disrupted potentially contributing to disease progression. The results show that interpretation of retinoid homeostasis on the basis of indirect markers such as retinol concentrations or mRNA data is probably misleading when evaluating human disease processes, and analysis of the broader retinoid metabolome is needed to characterize disease effects on retinoid signaling.

Effects of feeding on plasma concentrations of vitamin A in captive African penguins (Spheniscus demersus).

Vitamin A comprises vitamin A1 and vitamin A2; vitamin A1 is retinol and its fatty-acid esters and vitamin A2 is 3,4-didehydroretinol and its fatty-acid esters. Although vitamin A1 is generally recognized as the major vitamin A, vitamin A2 is found in some birds and mammals that eat fish containing vitamin A2. Plasma concentration of retinyl esters, but not retinol, is known to increase postprandially in humans. The objectives of this study were to confirm the presence of vitamin A2 in fish fed to penguins, and in penguin plasma, and the postprandial changes in vitamin A concentration in penguin plasma. Blood was collected from six male African penguins (Spheniscus demersus) before and after feeding on jack mackerels (Trachurus japonicus) along with a vitamin premix containing vitamin A1. Vitamin A1 concentration in fish was much higher than the requirement, and was 5-fold higher than the vitamin A2 concentration. Vitamin A2 was present in plasma but its concentration was at least 100-fold below that of plasma retinol, suggesting that vitamin A2 is much less bioavailable than vitamin A1 in penguins. Plasma retinol and retinyl palmitate concentrations were found to be stable after the meal. Plasma retinol concentration is suggested to be homeostatically controlled in penguins against the rapid flow of vitamin A1 after meal. The absorbed vitamin A1 is thought to be transported to the liver via the portal vein for storage in penguins, resulting in stable retinyl palmitate concentration in plasma after meal.

A simple and robust quantitative analysis of retinol and retinyl palmitate using a liquid chromatographic isocratic method

Vitamin A is a vital nutritional substances that regulates biological activities including development, but is also associated with disease onset. The extent of vitamin A intake influences the retinoid content in the liver, the most important organ for the storage of vitamin A. Measurement of endogenous retinoid in biological samples is important to understand retinoid homeostasis. Here we present a reliable, highly sensitive, and robust method for the quantification of retinol and retinyl palmitate using a reverse-phase HPLC/UV isocratic method. We determined the impact of chronic dietary vitamin A on retinoid levels in livers of mice fed an AIN-93G semi-purified diet (4 IU/g) compared with an excess vitamin A diet (1000 IU/g) over a period from birth to 10 weeks of age. Coefficients of variation for intra-assays for both retinoids were less than 5%, suggesting a higher reproducibility than any other HPLC/UV gradient method. Limits of detection and quantification for retinol were 0.08 pmol, and 0.27 pmol, respectively, which are remarkably higher than previous results. Supplementation with higher doses of vitamin A over the study period significantly increased liver retinol and retinyl palmitate concentrations in adult mice. The assays described here provide a sensitive and rigorous quantification of endogenous retinol and retinyl palmitate, which can be used to help determine retinoid homeostasis in disease states, such as toxic hepatitis and liver cancer.

Toxicological characterisation of two novel selective aryl hydrocarbon receptor modulators in Sprague-Dawley rats

The aryl hydrocarbon receptor (AHR) mediates the toxicity of dioxins, but also plays important physiological roles. Selective AHR modulators, which elicit some effects imparted by this receptor without causing the marked toxicity of dioxins, are presently under intense scrutiny. Two novel such compounds are IMA-08401 (N-acetyl-N-phenyl-4-acetoxy-5-chloro-1,2-dihydro-1-methyl-2-oxo-quinoline-3-carboxamide) and IMA-07101 (N-acetyl-N-(4-trifluoromethylphenyl)-4-acetoxy-1,2-dihydro-5-methoxy-1-methyl-2-oxo-quinoline-3-carboxamide). They represent, as diacetyl prodrugs, AHR-active metabolites of the drug compounds laquinimod and tasquinimod, respectively, which are intended for the treatment of autoimmune diseases and cancer. Here, we toxicologically assessed the novel compounds in Sprague-Dawley rats, after a single dose (8.75–92.5mg/kg) and 5-day repeated dosing at the highest doses achievable (IMA-08401: 100mg/kg/day; and IMA-07101: 75mg/kg/day). There were no overt clinical signs of toxicity, but body weight gain was marginally retarded, and the treatments induced minimal hepatic extramedullary haematopoiesis. Further, both the absolute and relative weights of the thymus were significantly decreased. Cyp1a1 gene expression was substantially increased in all tissues examined. The hepatic induction profile of other AHR battery genes was distinct from that caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The only marked alterations in serum clinical chemistry variables were a reduction in triglycerides and an increase in 3-hydroxybutyrate. Liver and kidney retinol and retinyl palmitate concentrations were affected largely in the same manner as reported for TCDD. In vitro, the novel compounds activated CYP1A1 effectively in H4IIE cells. Altogether, these novel compounds appear to act as potent activators of the AHR, but lack some major characteristic toxicities of dioxins. They therefore represent promising new selective AHR modulators.

β-Cryptoxanthin Reduced Lung Tumor Multiplicity and Inhibited Lung Cancer Cell Motility by Downregulating Nicotinic Acetylcholine Receptor α7 Signaling.

Despite the consistent association between a higher intake of the provitamin A carotenoid β-cryptoxanthin (BCX) and a lower risk of lung cancer among smokers, potential mechanisms supporting BCX as a chemopreventive agent are needed. We first examined the effects of BCX on 4-[methyl nitrosamino]-1-[3-pyridyl]-1-butanone (NNK)-induced lung tumorigenesis in A/J mice. BCX supplementation was given daily to the mice starting 2 weeks prior to the injection of NNK and continued 16 weeks after NNK injection. BCX supplementation resulted in a dose-dependent increase of BCX concentration in both serum and lungs of the mice without a significant alteration of vitamin A (retinol and retinyl palmitate) concentration. BCX significantly reduced the multiplicity of the NNK-induced lung tumor by 52% to 63% compared with the NNK-treated mice without BCX supplementation. The protective effect of BCX in the lungs was associated with reductions of both mRNA and protein of the homopentameric neuronal nicotinic acetylcholine receptor α7 (α7-nAChR), which has been implicated in lung tumorigenesis. We then conducted an in vitro cell culture study and found that BCX treatment suppressed α7-nAChR expression and inhibited the migration and invasion of α7-nAChR-positive lung cancer cells but not in cells lacking α7-nAChR. The activities of BCX were significantly attenuated by activators of α7-nAChR/PI3K signaling or by overexpression of constitutively active PI3K. Collectively, the results suggest that BCX inhibits lung tumorigenesis and cancer cell motility through the downregulation of α7-nAChR/PI3K signaling, independent of its provitamin A activity. Therefore, BCX can be used as a chemopreventive agent or a chemotherapeutic compound against lung cancer. Cancer Prev Res; 9(11); 875-86. ©2016 AACR.

Temporal plasma vitamin concentrations are altered by fat-soluble vitamin administration in suckling pigs.

Piglets are born with purportedly low plasma vitamin D levels. The objective of this study was to investigate the effect of fat-soluble vitamin administration, primarily vitamin D, by different administration routes on plasma vitamin concentrations in suckling pigs. A total of 45 pigs from 5 litters were allotted at birth to 3 treatments within each litter. Pigs were administered 400 IU of α-tocopherol, 40,000 IU of retinyl palmitate, and 40,000 IU of vitamin D at d 1 of age either orally or by i.m. injection and compared with control pigs with no supplemental vitamin administration. Blood samples were collected at d 0 (initial), 1, 2, 3, 4, 6, 9, 14, and 20 after administration. Plasma 25-hydroxycholecalciferol (25OHD), α-tocopherol, retinyl palmitate, and retinol concentrations were analyzed. Except for retinol, the effects of treatment, day, and day × treatment interaction ( < 0.01) were observed on plasma vitamin concentrations. Plasma concentrations of 25OHD and α-tocopherol increased immediately regardless of administration routes to peak at d 2 and 1 after administration, respectively. Plasma retinyl palmitate concentrations increased only with the injection treatment, with the peak at d 1 after administration. Plasma concentrations of 25OHD in both administration treatments and α-tocopherol in the injection treatment were maintained at greater levels than those in the control treatment until d 20 after administration. With regard to the pharmacokinetic parameters for plasma 25OHD concentrations, the injection treatment had greater elimination half-life ( < 0.01), maximum plasma concentrations ( < 0.05), and all area under the curve parameters ( < 0.01) but a lower elimination rate constant ( < 0.01) than the oral treatment. Relative bioavailability of oral administration compared with injection administration was 55.26%. These results indicate that plasma status of 25OHD,α-tocopherol, and retinyl palmitate are differentially changed between types of vitamins administered and between administration routes and that the injection route had a greater increase and slower disappearance of plasma vitamin levels than the oral route during the suckling period.

Effect of Hyperoxia on Retinoid Metabolism and Retinoid Receptor Expression in the Lungs of Newborn Mice.

BackgroundPreterm newborns that receive oxygen therapy often develop bronchopulmonary dysplasia (BPD), which is abnormal lung development characterized by impaired alveologenesis. Oxygen-mediated injury is thought to disrupt normal lung growth and development. However, the mechanism of hyperoxia-induced BPD has not been extensively investigated. We established a neonatal mouse model to investigate the effects of normobaric hyperoxia on retinoid metabolism and retinoid receptor expression.MethodsNewborn mice were exposed to hyperoxic or normoxic conditions for 15 days. The concentration of retinol and retinyl palmitate in the lung was measured by HPLC to gauge retinoid metabolism. Retinoid receptor mRNA levels were assessed by real-time PCR. Proliferation and retinoid receptor expression in A549 cells were assessed in the presence and absence of exogenous vitamin A.ResultsHyperoxia significantly reduced the body and lung weight of neonatal mice. Hyperoxia also downregulated expression of RARα, RARγ, and RXRγ in the lungs of neonatal mice. In vitro, hyperoxia inhibited proliferation and expression of retinoid receptors in A549 cells.ConclusionHyperoxia disrupted retinoid receptor expression in neonatal mice.

The Genetic Variant I148M in PNPLA3 Is Associated With Increased Hepatic Retinyl-Palmitate Storage in Humans.

Previous studies revealed that the common sequence variant I148M in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is associated with liver fat content and liver diseases, but not with insulin resistance. Recent data suggest that the PNPLA3 I148M variant has reduced retinyl-palmitate lipase activity in hepatic stellate cells. We hypothesized that the PNPLA3 I148M variant is associated with elevated retinyl-palmitate storage in human liver as a potential link to the clinical pathology. Design/Setting and Participants: Using HPLC, we quantified the retinoid metabolites in liver tissue extracts obtained from 42 human subjects, including 13 heterozygous and six homozygous carriers of the minor PNPLA3 I148M variant. Retinyl-palmitate is elevated in human livers of homozygous PNPLA3 I148M allele carriers Results: The PNPLA3 I148M variant was associated with a significant increase (1.4-fold) in liver fat. The content of retinyl-palmitate was elevated and the ratio of retinol/retinyl-palmitate was reduced in liver extracts obtained from homozygous PNPLA3 I148M minor allele carriers. In a multivariate model including liver fat content, these differences remained significant independent of liver fat content. The content of the minor retinyl-fatty acid esters was similarly increased in homozygous PNPLA3 I148M carriers. The increased content of hepatic retinyl-palmitate and the reduced ratio of retinol/retinyl-palmitate in PNPLA3 I148M minor allele carriers support in vitro findings of an altered retinyl-palmitate lipase activity. Our results indicate that the PNPLA3 I148M variant is relevant for the retinyl-palmitate content in human liver, providing a possible link to chronic liver disease.

Red palm oil–supplemented and biofortified cassava gari increase the carotenoid and retinyl palmitate concentrations of triacylglycerol-rich plasma in women

Boiled biofortified cassava containing β-carotene can increase retinyl palmitate in triacylglycerol-rich plasma. Thus, it might alleviate vitamin A deficiency. Cassava requires extensive preparation to decrease its level of cyanogenic glucosides, which can be fatal. Garification is a popular method of preparing cassava that removes cyanogen glucosides. Our objective was to compare the effectiveness of biofortified gari to gari prepared with red palm oil. The study was a randomized crossover trial in 8 American women. Three gari preparations separated by 2-week washout periods were consumed. Treatments (containing 200-225.9 g gari) were as follows: biofortified gari (containing 1 mg β-carotene), red palm oil–fortified gari (1 mg β-carotene), and unfortified gari with a 0.3-mg retinyl palmitate reference dose. Blood was collected 6 times from −0.5 to 9.5 hours after ingestion. Triacylglycerol-rich plasma was separated by ultracentrifugation and analyzed by high-performance liquid chromatography (HPLC) with diode array detection. Area under the curve for β-carotene, α-carotene, and retinyl palmitate increased after the fortified meals were fed (P < .05), although the retinyl palmitate increase induced by the red palm oil treatment was greater than that induced by the biofortified treatment (P < .05). Vitamin A conversion was 2.4 ± 0.3 and 4.2 ± 1.5 μg pro–vitamin A carotenoid/1 μg retinol (means ± SEM) for red palm oil and biofortified gari, respectively. These results show that both treatments increased β-carotene, α-carotene, and retinyl palmitate in triacylglycerol-rich plasma concentrations in healthy well-nourished adult women, supporting our hypothesis that both interventions could support efforts to alleviate vitamin A deficiency.

Bioactive Chitosan Nanoparticles Loaded with Retinyl Palmitate: A Simple Route Using Ionotropic Gelation

Nowadays, there is an increasing demand in incorporating antioxidants into biopolymeric nanoparticles (NPs) in order to enlarge their applications in the pharmaceutical and biomedical fields. The challenge of the work is to investigate the feasibility of encapsulating retinyl palmitate (RP) into chitosan (Ch) NP via ionotropic gelation. Two routes are addressed in the preparation of the systems, and they have an influence on the physicochemical properties of the NP in addition to the antioxidant amount loaded. The resulting RP‐encapsulated NP has pseudo spherical morphology, average hydrodynamic diameters between 230 and 350 nm and zeta potential values between +12.5 and +30 mV, depending on RP load and procedure. Encapsulation efficiency ranges from about 35% to 64%, and the loading capacity between 4% and 10%. The antioxidant activity studied by the 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) assay and cytotoxicity of RP‐loaded NP evaluated against human dermal fibroblasts is dependent on RP content and NP concentration. image

Lack of Impact of High Dietary Vitamin A on T Helper 2-Dependent Contact Hypersensitivity to Fluorescein Isothiocyanate in Mice.

Overuse of vitamin A as a dietary supplement is a concern in industrialized countries. High-level dietary vitamin A is thought to shift immunity to a T helper 2 (Th2)-dominant one, resulting in the promotion of allergies. We have been studying a fluorescein isothiocyanate (FITC)-induced contact hypersensitivity (CHS) mouse model that involves Th2-type immunity. We fed a diet with a high retinyl palmitate content (250 international units (IU)/g diet) or a control diet (4 IU/g diet) to BALB/c mice for three weeks. No augmentation of FITC-induced CHS was found in mice fed the diet with a high vitamin A content, although accumulation of the vitamin was confirmed in the livers of these animals. The results indicated that relatively short-term feeding of the high-level vitamin A diet did not influence the Th2-driven response at a stage with significant retinol accumulation in the liver. The results were in contrast to the high-dose pyridoxine diets that produced a reduced response in FITC-induced CHS.

Supplemental β-carotene I: Effect on plasma vitamin A, growth, performance, and carcass characteristics of feedlot cattle

To evaluate the effects of β-carotene (βC) on performance and carcass characteristics, 112 crossbred calves were allotted to 4 treatments consisting of retinyl palmitate (RP) supplemented at 2200IU/kg, and synthetic β-carotene supplemented at 1 (SβC1X), 5 (SβC5X), or 10 (SβC10X) times RP. Compared to RP, SβC1X did not impact performance (P≥0.25) or plasma concentrations of retinoids or carotenoids (P≥0.26). Increasing dietary βC increased (P≤0.04) plasma concentrations of RP and all of the isomers of βC, but did not affect weight, gain, or gain:feed (P≥0.24). Marbling and fat thickness did not differ between RP and SβC1X or because of amount of βC (P≥0.35). Lightness (L*) of LM decreased with increasing concentration of SβC (linear; P=0.01). Yellowness (b*) increased (P=0.04) and redness (a*) tended to increase (P=0.09) in subcutaneous fat as SβC amount increased (quadratic).