Corrigendum: Safe and effective delivery of supplemental iron to healthy adults: a two-phase, randomized, double-blind trial - the safe iron study

[This corrects the article DOI: 10.3389/fnut.2023.1230061.].

Safe and effective delivery of supplemental iron to healthy adults: a two-phase, randomized, double-blind trial - the safe iron study

Introduction

The safety of novel forms of iron in healthy, iron-replete adults as might occur if used in population-based iron supplementation programs was examined. We tested the hypotheses that supplementation with nanoparticulate iron hydroxide adipate tartrate (IHAT), an iron-enriched Aspergillus oryzae product (ASP), or ferrous sulphate heptahydrate (FS) are safe as indicated by erythrocyte susceptibility to malarial infection, bacterial proliferation, and gut inflammation. Responses to FS administered daily or weekly, and with or without other micronutrients were compared.

Methods

Two phases of randomized, double-blinded trials were conducted in Boston, MA. Phase I randomized 160 volunteers to six treatments: placebo, IHAT, ASP, FS, and FS plus a micronutrient powder (MNP) administrated daily at 60 mg Fe/day; and FS administered as a single weekly dose of 420 mg Fe. Phase II randomized 86 volunteers to IHAT, ASP, or FS administered at 120 mg Fe/day. Completing these phases were 151 and 77 participants, respectively. The study was powered to detect effects on primary endpoints: susceptibility of participant erythrocytes to infection by Plasmodium falciparum, the proliferation potential of selected pathogenic bacteria in sera, and markers of gut inflammation. Secondary endpoints for which the study was not powered included indicators of iron status and gastrointestinal symptoms.

Results

Supplementation with any form of iron did not affect any primary endpoint. In Phase I, the frequency of gastrointestinal symptoms associated with FS was unaffected by dosing with MNP or weekly administration; but participants taking IHAT more frequently reported abdominal pain (27%, p < 0.008) and nausea (4%, p = 0.009) than those taking FS, while those taking ASP more frequently reported nausea (8%, p = 0.009). Surprisingly, only 9% of participants taking IHAT at 120 mg Fe/day (Phase II) reported abdominal pain and no other group reported that symptom.

Discussion

With respect to the primary endpoints, few differences were found when comparing these forms of iron, indicating that 28 days of 60 or 120 mg/day of IHAT, ASP, or FS may be safe for healthy, iron-replete adults. With respect to other endpoints, subjects receiving IHAT more frequently reported abdominal pain and nausea, suggesting the need for further study.

Clinical Trial Registration

ClinicalTrials.gov, NCT03212677; registered: 11 July 2017.

Comparison of Plasma Metabolome Response to Diets Enriched in Soybean and Partially-Hydrogenated Soybean Oil in Moderately Hypercholesterolemic Adults-A Pilot Study

Partially-hydrogenated fat/trans fatty acid intake has been associated with adverse effects on cardiometabolic risk factors. Comparatively unexplored is the effect of unmodified oil relative to partially-hydrogenated fat on the plasma metabolite profile and lipid-related pathways. To address this gap, we conducted secondary analyses using a subset of samples randomly selected from a controlled dietary intervention trial involving moderately hypercholesterolemic individuals. Participants (N = 10, 63 ± 8 y, BMI, 26.2 ± 4.2 kg/m2, LDL-C, 3.9 ± 0.5 mmol/L) were provided with diets enriched in soybean oil (SO) and partially-hydrogenated soybean oil (PHSO). Plasma metabolite concentrations were determined using an untargeted approach and pathway analysis using LIPIDMAPS. Data were assessed using a volcano plot, receiver operating characteristics curve, partial least square-discrimination analysis and Pearson correlations. Among the known metabolites higher in plasma after the PHSO diet than the SO diet, the majority were phospholipids (53%) and di- and triglycerides (DG/TG, 34%). Pathway analysis indicated upregulation of phosphatidylcholine synthesis from DG and phosphatidylethanolamine. We identified seven metabolites (TG_56:9, TG_54:8, TG_54:7, TG_54:6, TG_48:5, DG_36:5 and benproperine) as potential biomarkers for PHSO intake. These data indicate that TG-related metabolites were the most affected lipid species, and glycerophospholipid biosynthesis was the most active pathway in response to PHSO compared to SO intake.

An Exploratory Case-Control Study on the Associations of Bacterially-Derived Vitamin K Forms with the Intestinal Microbiome and Obesity-Related Osteoarthritis

Background

Evidence suggests that natural metabolites produced by intestinal microorganisms may have beneficial or harmful effects on osteoarthritis (OA). This could include menaquinones, which are bacterially-synthesized, biologically-active vitamin K forms abundant in the intestinal microbiome.

Objectives

The overall goal of this study was to evaluate the association of intestinally-derived menaquinones with obesity-related OA.

Methods

This case-control study used data and biospecimens derived from a subgroup of Johnston County Osteoarthritis Study participants. Fecal menaquinone concentrations and microbial composition were determined in 52 obese participants with hand and knee OA and 42 age- and sex-matched obese participants without OA. The inter-relationships among fecal menaquinones were evaluated using principal component analysis. The differences in alpha and beta diversities and microbial composition across menaquinone clusters were evaluated using ANOVA.

Results

The samples were clustered into the following 3 groups: cluster 1 characterized by higher fecal menaquinone-9 and -10 concentrations, cluster 2 characterized by lower overall menaquinone concentrations, and cluster 3 characterized by higher menaquinone-12 and -13 concentrations. Overall, fecal menaquinone clusters did not differ between participants with or without OA (P = 0.707). Microbial diversity did not differ across the fecal menaquinone clusters (all F-test P > 0.12). However, the relative abundance of bacterial taxa differed among clusters, with higher abundance of Coprococcus, Prevotella, and Eggerthella in cluster 2 than in cluster 1; higher abundance of Oscillospira, Dorea, Eubacterium, and Bacteroides in cluster 3 than in cluster 1; and higher abundance of Prevotella, Sutterella, and Dorea in cluster 3 than in cluster 2 (all P < 0.001).

Conclusion

Menaquinones were variable and abundant in the human gut, but the fecal menaquinone clusters did not differ with OA status. Although the relative abundance of specific bacterial taxa differed among fecal menaquinone clusters, the relevance of these differences with respect to vitamin K status and human health is uncertain.

Abstract P425: Diets Enriched in Stearate, Palmitate, and Oleate Differentially Modulate Gut Microbiome Composition in Post-Menopausal Women

Objective: Dietary stearic acid (18:0), a major saturated fatty acid (SFA) in Western diets, does not raise plasma LDL-C concentrations relative to other shorter chain SFAs (palmitic [16:0], myristic [14:0] and lauric [12:0]), and is associated with lower CVD risk. We investigated whether the cardioprotective effects of 18:0 and its metabolic product oleic acid (18:1, a monounsaturated fatty acid) relative to 16:0 is mediated via alterations in the gut microbiome.

Methods: Twenty mildly hypercholesterolemic (LDL-C>100mg/dL) post-menopausal women (50-85 years; BMI 25-35kg/m 2 ) consumed each of 3 isocaloric diets for 5 weeks according to a randomized controlled cross-over design. Diets provided 55%E carbohydrate, 15%E protein and 30%E fat with half of the fat provided by 16:0, 18:0 or 18:1, respectively. Fecal samples were collected at the end of each diet phase and shotgun metagenomic sequencing was performed. Alpha diversity (Shannon index, Simpson index and observed counts) was compared between diet groups using two-sample non-parametric tests. Beta-diversity was assessed using Bray-Curtis dissimilarity with PERMANOVA test. Differences in metagenomic features by diet group were evaluated using Partial Least Squares-Discriminant Analysis (PLS-DA) models of pairwise diet differences developed using the R package ‘mixOmics’.

Results: No significant differences were observed in alpha and beta diversity between diet groups. However, the variability in microbial relative abundance was greater after participants consumed the 18:0 and 18:1 diets compared to the 16:0 diet. Specifically, mean relative abundance of Bacterioides dorei , Bacteroides vulgatus , and Ruminococcus were highest after participants consumed the 18:0 relative to the 16:0 diet and intermediate after the 18:1 diet. The relative abundance of Coprococcus , Parabacteroides distasonis , Coprobacillus and Blautia were higher after participants consumed the 18:1 relative to the 16:0 diet. These microbial species have been associated with several anti-inflammatory pathways and decreased bacterial lipopolysaccharide production.

Conclusion: These data document modest but distinctive effects of dietary SFAs on gut microbiome composition and functionality, suggesting that the favorable effects of 18:0 and 18:1 relative to 16:0 on CVD risk factors could be mediated, in part, by the gut microbiome.

Brain vitamin D forms, cognitive decline, and neuropathology in community‐dwelling older adults

INTRODUCTION

Vitamin D purportedly protects against cognitive decline and dementia based on observational data using circulating 25-hydroxyvitamin D (25(OH)D). Little is known about vitamin D in the human brain and the association with dementia or neuropathology.

METHODS

Decedents of the Rush Memory and Aging Project (n = 290) had vitamin D concentrations measured in four brain regions. Associations with cognitive and neuropathological outcomes were estimated using linear and logistic regression.

RESULTS

The main form of vitamin D in all brain regions measured was 25(OH)D₃ . Higher brain 25(OH)D₃ concentrations were associated with a 25% to 33% lower odds of dementia or mild cognitive impairment (MCI) at the last visit before death (all P ≤ .031). However, brain 25(OH)D concentrations were not associated with any post-mortem neuropathology outcome studied.

DISCUSSION

Higher brain 25(OH)D₃ concentrations were associated with better cognitive function prior to death. Additional research is needed to clarify the specific mechanisms underlying this potentially protective relationship.

Beta-Cryptoxanthin Supplementation Protects Against Liver Cancer Progression and Correlates With Altered Targeted and Untargeted Metabolomic Profiles in Mice

Objectives

Nonalcoholic fatty liver disease (NAFLD)-associated hepatocellular carcinoma (HCC) is expected to increase globally in the upcoming years. Diets high in refined carbohydrates and added sugars (HRCD) have been linked to NAFLD progression. Previous studies have demonstrated that retinoids possess anti-tumorigenic properties, yet less is known about whether upstream provitamin A carotenoids exhibit similar characteristics. We recently demonstrated that dietary beta-cryptoxanthin (BCX), a provitamin A carotenoid, decreased NAFLD severity and HCC progression in diethylnitrosamine (DEN)-initiated, high refined carbohydrate diet (HRCD)-fed mice. In this study, we evaluated the effects of dietary BCX supplementation on modulating plasma biomarkers, hepatic vitamin A status, and plasma metabolomic profiles in our DEN-initiated, HRCD-promoted model of HCC.

Methods

Male, six-week-old C57BL/6J mice were injected with DEN (25 mg/kg BW) and a fed a HRCD (66.5% carbs including sucrose) with or without BCX supplementation (10 mg/kg diet) for 24 weeks. Using plasma samples, we performed metabolomics using our UHPLC-QTOF-MS platform, a targeted Biocrates MxP Quant 500 kit, and a complimentary untargeted analysis of phospholipids from the METLIN database to identify metabolites which correlate with primary outcomes. Hepatic vitamin A levels were determined via HPLC.

Results

Compared to HRCD-fed, DEN-injected mice, mice fed BCX displayed significantly lower tumor burden and steatosis, higher hepatic vitamin A status, and lower plasma levels of alanine transaminase (ALT) and lactate dehydrogenase (LDH). Moderate negative correlations were also identified amongst hepatic vitamin A levels and primary outcomes, such as HCC tumor number, steatosis score, and relevant biomarkers. Our metabolomics data showed significant modulations in metabolites with BCX treatment from phosphatidylcholine, sphingomyelin, ceramide, bile acid, and other phospholipid classes.

Conclusions

BCX supplementation significantly reduced HCC severity, increased hepatic vitamin A status, reduced plasma levels of ALT and LDH, and altered several lipid-related classes of metabolites, thus supporting a chemopreventive potential for BCX against HRCD-promoted HCC development.

Funding Sources

USDA/ARS and NIFA/AFRI.

Ablation of Carotenoid Cleavage Enzymes BCO1 & BCO2 Alters Gut Microbial and Plasma Metabolomic Profiles in High Refined Carbohydrate Diet-Fed Mice

Objectives

β-Carotene-15,15′-oxygenase (BCO1) and β-carotene-9′,10′-oxygenase (BCO2) cleave carotenoids to form vitamin A or apo-carotenoid species. Beyond these roles, BCO1 and BCO2 have been implicated in modulating lipid, cholesterol, and oxidative stress-related processes, yet less is known about their combined influence on shaping gut microbial and plasma metabolic profiles. Current intake of refined carbohydrates and added sugars exceeds the recommendations within the Dietary Guidelines for Americans, which may contribute to the development of nonalcoholic fatty liver disease (NAFLD). In the present study, we aimed to uncover whether mice with systemic ablation of BCO1-/-/BCO2-/- (DKO) display distinctive phenotypes in response to a high refined carbohydrate diet (HRCD) model of NAFLD.

Methods

Male, six-week-old C57BL/6J wild type mice (WT) and DKO mice were fed a chow diet or a HRCD (66.5% carbs including sucrose) for 24 weeks. We used fecal and plasma samples to respectively perform 16S rDNA sequencing, and both targeted and untargeted metabolomics using our UHPLC-QTOF-MS platform, a targeted Biocrates MxP Quant 500 kit, and a complimentary untargeted analysis of phospholipids from the METLIN database. Data were analyzed using QIIME2-DEseq2, MetaboAnalyst 5.0, MassHunter Qualitative Analysis, and MicrobiomeAnalyst.

Results

HRCD-fed WT and DKO mice developed similar levels of hepatic steatosis although DKO mice had significantly higher hepatic levels of malondialdehyde (MDA). Interestingly, in both chow-fed and HRCD-fed DKO mice, plasma adiponectin and hepatic bile acids were significantly lower compared to respective WT groups. Our metabolomics data revealed that DKO mice displayed significant alterations in ceramide, cholesterol ester, triglyceride, and phospholipid classes under both chow and HRCD conditions. Additionally, when compared to HRCD-fed WT mice, HRCD-fed DKO mice displayed significantly reduced alpha diversity and possessed significant compositional differences based on Bray Curtis dissimilarity measures.

Conclusions

BCO1/BCO2 DKO mice display altered metabolomic and gut microbial profiles. Carotenoid cleavage enzymes affect diverse physiological processes, which involve lipid metabolism and the gut microbiome.

Funding Sources

USDA/ARS and NIFA/AFRI.

Association of vitamin K with cognitive decline and neuropathology in community‐dwelling older persons

Higher vitamin K intakes have been associated with better cognitive function, suggestive of a vitamin K mechanistic effect or simply reflective of a healthy diet. To test the hypothesis that brain vitamin K is linked to cognitive decline and dementia, vitamin K concentrations were measured in four brain regions, and their associations with cognitive and neuropathological outcomes were estimated in 325 decedents of the Rush Memory and Aging Project. Menaquinone‐4 (MK4) was the main vitamin K form in the brain regions evaluated. Higher brain MK4 concentrations were associated with a 17% to 20% lower odds of dementia or mild cognitive impairment (MCI) (P‐value < .014), with a 14% to 16% lower odds of Braak stage ≥IV (P‐value < 0.045), with lower Alzheimer's disease global pathology scores and fewer neuronal neurofibrillary tangles (P‐value < 0.012). These findings provide new and compelling evidence implicating vitamin K in neuropathology underlying cognitive decline and dementia.

Evaluation of PIQNIQ, a Novel Mobile Application for Capturing Dietary Intake

BACKGROUND

Accurate measurement of dietary intake is vital for providing nutrition interventions and understanding the complex role of diet in health. Traditional dietary assessment methods are very resource intensive and burdensome to participants. Technology may help mitigate these limitations and improve dietary data capture.

OBJECTIVE

Our objective was to evaluate the accuracy of a novel mobile application (PIQNIQ) in capturing dietary intake by self-report. Our secondary objective was to assess whether food capture using PIQNIQ was comparable with an interviewer-assisted 24-h recall (24HR).

METHODS

This study was a single-center randomized clinical trial enrolling 132 adults aged 18 to 65 y from the general population. Under a provided-food protocol with 3 menus designed to include a variety of foods, participants were randomly assigned to 1 of 3 food capture methods: simultaneous entry using PIQNIQ, photo-assisted recall using PIQNIQ, and 24HR. Primary outcomes were energy and nutrient content (calories, total fat, carbohydrates, protein, added sugars, calcium, dietary fiber, folate, iron, magnesium, potassium, saturated fat, sodium, and vitamins A, C, D, and E) captured by the 3 methods.

RESULTS

The majority of nutrients reported were within 30% of consumed intake in all 3 food capture methods (n = 129 completers). Reported intake was highly (>30%) overestimated for added sugars in both PIQNIQ groups and underestimated for calcium in the photo-assisted recall group only (P < 0.001 for all). However, in general, both PIQNIQ methods had similar levels of accuracy and were comparable to the 24HR except in their overestimation (>30%) of added sugars and total fat (P < 0.001 for both).

CONCLUSIONS

Our results suggest that intuitive, technology-based methods of dietary data capture are well suited to modern users and, with proper execution, can provide data that are comparable to data obtained with traditional methods. This trial was registered at clinicaltrials.gov as NCT03578458.

Perspective: US Documentation and Regulation of Human Nutrition Randomized Controlled Trials

Training to ensure good documentation practices and adherence to regulatory requirements in human nutrition randomized controlled trials has not been given sufficient attention. Furthermore, it is difficult to find this information conveniently organized or in a form relevant to nutrition protocols. Current gaps in training and research surveillance exist in clinical nutrition research because training modules emphasize drugs and devices, promote reliance on monitoring boards, and lack nutrition expertise on human nutrition research teams. Additionally, because eating is essential, ongoing, and highly individualized, it is difficult to distinguish risks associated with interventions from eating under free-living conditions. Controlled-feeding trials provide an option to gain more experimental control over food consumed, but at a price of less external validity, and may pose human behavior issues that are unrelated to the intervention. This paper covers many of the expected practices for documentation and regulation that may be encountered in planning and conducting nutrition intervention trials with examples and references that should be useful to clinical nutrition researchers, funders of research, and research institutions. Included are definitions and guidance on clinical nutrition research oversight (institutional review boards, data safety and monitoring boards, US FDA); participant safety; standard operating procedures; training of investigators, staff, and students; and local culture and reporting requirements relevant to diet-related clinical research conduct and documentation.

Associations between Circulating Lipids and Fat-Soluble Vitamins and Carotenoids in Healthy Overweight and Obese Men

Inconsistent associations between lipids and circulating markers of fat-soluble vitamin and carotenoid status have been reported. The aim of this hypothesis-generating study was to examine the contribution of the LC-MS-based lipidome, characterized by lipid class, carbon count, and the number of unsaturated bonds, to the interindividual variability in circulating concentrations of retinol, carotenoids, 25-hydroxyvitamin D3, α-tocopherol, γ-tocopherol, and phylloquinone in 35 overweight and obese, but healthy men. A sparse partial least-squares method was used to accomplish this aim. Highly abundant phospholipids and triglycerides (TGs) contributed to the interindividual variability in phylloquinone, α-tocopherol, and γ-tocopherol. Interindividual variability in lycopene concentrations was driven by concentrations of low-abundant TG. 25-Hydroxyvitamin D3, retinol, and the other carotenoids were not influenced by lipids. Except for lycopene, evaluation of lipids beyond class does not appear to further explain the interindividual variability in circulating concentrations of fat-soluble vitamins and carotenoids.

Vitamin K status, cardiovascular disease, and all-cause mortality: a participant-level meta-analysis of 3 US cohorts

BACKGROUND

Vitamin K-dependent proteins in vascular tissue affect vascular stiffness and calcification, which is associated with cardiovascular disease (CVD) and all-cause mortality.

OBJECTIVE

To determine the association of circulating vitamin K concentrations with CVD and all-cause mortality by conducting a participant-level meta-analysis.

METHODS

We obtained individual participant-level data from the Health, Aging, and Body Composition Study, the Multi-Ethnic Study of Atherosclerosis, and the Framingham Offspring Study, known cohorts with available measures of fasting circulating phylloquinone (vitamin K-1) and confirmed CVD events and mortality. Circulating phylloquinone was measured in a central laboratory from fasting blood samples and categorized as ≤0.5 nmol/L, >0.5-1.0 nmol/L, and >1.0 nmol/L. Multivariable Cox proportional hazard regression with multiple imputations was used to evaluate the association of circulating phylloquinone with incident CVD and all-cause mortality risk.

RESULTS

Among 3891 participants (mean age 65 ± 11 y; 55% women; 35% nonwhite), there were 858 incident CVD events and 1209 deaths over a median of 13.0 y. The risk of CVD did not significantly differ according to circulating phylloquinone [fully adjusted HR (95% CI) relative to >1.0 nmol/L: ≤0.5 nmol/L, 1.12 (0.94, 1.33); >0.5-1.0 nmol/L, 1.02 (0.86, 1.20)]. Participants with ≤0.5 nmol/L circulating phylloquinone had an adjusted 19% higher risk of all-cause mortality compared with those with >1.0 nmol/L [fully adjusted HR (95% CI): 1.19 (1.03, 1.38)]. Mortality risk was similar in participants with >0.5-1.0 nmol/L compared with >1.0 nmol/L [fully adjusted HR (95% CI): 1.04 (0.92, 1.17)].

CONCLUSIONS

Low circulating phylloquinone concentrations were associated with an increased risk of all-cause mortality, but not of CVD. Additional studies are needed to clarify the mechanism underlying this association and evaluate the impact of increased phylloquinone intake on cardiovascular and other health outcomes in individuals with low vitamin K status.

The Contribution of Lipids to the Interindividual Response of Vitamin K Biomarkers to Vitamin K Supplementation

SCOPE

A better understanding of factors contributing to interindividual variability in biomarkers of vitamin K can enhance the understanding of the equivocal role of vitamin K in cardiovascular disease. Based on the known biology of phylloquinone, the major form of vitamin K, it is hypothesized that plasma lipids contribute to the variable response of biomarkers of vitamin K metabolism to phylloquinone supplementation.

METHODS AND RESULTS

The association of plasma lipids and 27 lipid-related genetic variants with the response of biomarkers of vitamin K metabolism is examined in a secondary analysis of data from a 3-year phylloquinone supplementation trial in men (n = 66) and women (n = 85). Year 3 plasma triglycerides (TG), but not total cholesterol, LDL-cholesterol, or HDL-cholesterol, are associated with the plasma phylloquinone response (men: β = 1.01, p < 0.001, R2  = 0.34; women: β = 0.61, p = 0.008, R2  = 0.11; sex interaction p = 0.077). Four variants and the TG-weighted genetic risk score are associated with the plasma phylloquinone response in men only. Plasma lipids are not associated with changes in biomarkers of vitamin K function (undercarboxylated osteocalcin and matrix gla protein) in either sex.

CONCLUSION

Plasma TG are an important determinant of the interindividual response of plasma phylloquinone to phylloquinone supplementation, but changes in biomarkers of vitamin K carboxylation are not influenced by lipids.

A Meta-analysis of Vitamin K Status and Cardiovascular Disease (OR33-01-19)

Objectives

Evidence suggests low vitamin K status may be associated with an increased cardiovascular disease (CVD) risk in people with CVD risk factors. The objective of this study was to summarize the association between vitamin K status and CVD, overall and according to baseline CVD risk, by conducting a participant-level meta-analysis using data from the Framingham Offspring Study, the Health, Aging, and Body Composition Study (Health ABC), and the Multi-ethnic Study of Atherosclerosis (MESA).

Methods

Circulating phylloquinone (vitamin K1), measured from baseline fasting blood samples, was categorized as ≤0.5 nM, >0.5 - ≤1.0 nM and >1.0 nM. CVD was defined as confirmed ischemic heart disease, angina, resuscitated cardiac arrest, fatal or non-fatal myocardial infarction or stroke. Multivariable Cox proportional hazards models were used to evaluate the association between circulating phylloquinone and incident CVD overall and stratified according to baseline CVD risk factors.

Results

Among the 3622 participants (mean (SD) baseline age 65 (11), 45% men, 65% white), there were 785 CVD events over a median of 13.0 years. Overall the risk for CVD did not differ significantly according to circulating phylloquinone categories [HR(95%CI) for CVD, compared to plasma phylloquinone >1.0 nM: ≤0.5 nM = 1.15 (0.96–1.38); >0.5 - ≤1.0 nM = 0.99 (0.84–1.18)]. However, lower circulating phylloquinone was associated with higher incident CVD risk in those with diabetes, with a normal BMI, and in women (Table).

Conclusions

Overall, we did not detect any significant differences in CVD risk across circulating phylloquinone categories in community-dwelling adults. However, low circulating phylloquinone was associated with a higher CVD risk among certain sub-groups, but additional studies are needed to clarify if improving vitamin K status will benefit the cardiovascular health of certain segments of the population.

Funding Sources

Supported by NHLBI R21HL133421 and the USDA ARS Cooperative Agreement (58‐1950‐7‐707).

Supporting Tables, Images and/or Graphs

Associations of Lipid-related SNPs with Circulating Phylloquinone Are Proportional with Triglycerides (P15-008-19)

Objectives

Phylloquinone is transported on triglyceride-rich lipoproteins. Preliminary evidence from a genome-wide association meta-analysis suggests that genetic variants that influence triglycerides (TGs), such as rs964184 at the APOA1/C3/A4/A5 gene cluster, also influence circulating phylloquinone. To further evaluate this overlap, we examined the linear relationship between a weighted TG genetic risk score (wTG-GRS) with circulating phylloquinone.

Methods

We constructed a wTG-GRS comprised of 20 SNPs that were previously associated with TGs in a genome-wide association meta-analysis for blood lipids (n > 188,000 individuals of European ancestry). The assigned weights corresponded to the effect-sizes (β) reported for each SNP's association with TGs. With meta-analytic summary statistic data from a separate genome-wide association meta-analysis of circulating phylloquinone (n = 2138 individuals of European ancestry), a statistical technique was used to approximate the linear association of the wTG-GRS with circulating phylloquinone. A p-value of 0.05 for the estimate was considered statistically significant. First, the estimate was calculated without adjustment for TGs using Model 1 summary statistics, then calculated with adjustment for TGs using Model 2 summary statistics.

Results

The estimate for the linear association of the wTG-GRS with circulating phylloquinone was significant without and with adjustment for TGs (Model 1: β = 0.052, P = < 0.0001, Model 2: β = 0.027, P = 0.0001, respectively). The goodness-of-fit of the model was improved from Model 1 (p-het = 0.022) to Model 2 (p-het = 0.054).

Conclusions

The associations of TG-related SNPs with circulating phylloquinone were proportional to their associations with TGs. This provides further evidence of the shared genetic links between TGs and phylloquinone and suggests genetic studies of vitamin K should consider TGs.

Funding Sources

Study supported by the USDA Agricultural Research Service under Cooperative Agreement No. 58-1950-7-707 and NHLBI T32HL069772.

Autism Genetic Database (AGD): a comprehensive database including autism susceptibility gene-CNVs integrated with known noncoding RNAs and fragile sites

Background

Autism is a highly heritable complex neurodevelopmental disorder, therefore identifying its genetic basis has been challenging. To date, numerous susceptibility genes and chromosomal abnormalities have been reported in association with autism, but most discoveries either fail to be replicated or account for a small effect. Thus, in most cases the underlying causative genetic mechanisms are not fully understood. In the present work, the Autism Genetic Database (AGD) was developed as a literature-driven, web-based, and easy to access database designed with the aim of creating a comprehensive repository for all the currently reported genes and genomic copy number variations (CNVs) associated with autism in order to further facilitate the assessment of these autism susceptibility genetic factors.

Description

AGD is a relational database that organizes data resulting from exhaustive literature searches for reported susceptibility genes and CNVs associated with autism. Furthermore, genomic information about human fragile sites and noncoding RNAs was also downloaded and parsed from miRBase, snoRNA-LBME-db, piRNABank, and the MIT/ICBP siRNA database. A web client genome browser enables viewing of the features while a web client query tool provides access to more specific information for the features. When applicable, links to external databases including GenBank, PubMed, miRBase, snoRNA-LBME-db, piRNABank, and the MIT siRNA database are provided.

Conclusion

AGD comprises a comprehensive list of susceptibility genes and copy number variations reported to-date in association with autism, as well as all known human noncoding RNA genes and fragile sites. Such a unique and inclusive autism genetic database will facilitate the evaluation of autism susceptibility factors in relation to known human noncoding RNAs and fragile sites, impacting on human diseases. As a result, this new autism database offers a valuable tool for the research community to evaluate genetic findings for this complex multifactorial disorder in an integrated format. AGD provides a genome browser and a web based query client for conveniently selecting features of interest. Access to AGD is freely available at .

A simple pneumatic device for plunge-freezing cells grown on electron microscopy grids

A detailed design for a simple and inexpensive variable-speed (1.0-5.8 m s-1) pneumatic plunge-freezing device is presented. Cultured cells, grown on Formvar-coated 75-mesh gold finder grids, are pneumatically driven into a stirring mixture of propane/isopentane (3:1) cooled by liquid nitrogen (LN2). Premature freezing of the sample in the cryogenic vapors above the cryogen is prevented by plunging through an entry tube into an insulating box, to which a partial vacuum is applied. The cryogenic vapors are drafted into the box at the level of the liquid cryogen by the vacuum, thereby preventing a layer of cold gas from collecting above the cryogen. To prevent the sample from thawing during transfer from the cryogen to the substitution medium, the box top is removed and compressed air is forced through a corrugated tube running the length of the box. The resulting boiling LN2 creates an atmosphere below -120 degrees C in which the transfer can be accomplished.