Dietary Depletion Research Articles

TMET-27. MACHINE LEARNING-BASED IDENTIFICATION OF METABOLIC FLUXES IN PATIENT BRAIN TUMORS

Abstract Personalized oncology aims to match effective treatments for individual cancer patients based on the biology of an individual tumor. This approach is not possible for metabolic therapies due to our inability to quantify metabolic activity in patient tumors, even when patients are infused with 13C-glucose. We overcame this challenge by generating training data with a prior knowledge of 13C-glucose infused patient data and implementing a machine learning model to predict fluxes. We trained a convolutional neural network (CNN) to predict flux ratios. To validate our model, we compared predicted flux ratios to the experimental 13C-glucose-infused mouse models to predict treatment responses for: (1) pharmacologic inhibition of de novo GMP synthesis and (2) environmental serine restriction. Our GMP synthesis model predicted elevated GMP synthesis in GBM compared to cortex in a mouse model and discriminated between sources of GMP synthesis in patients. These findings allow prediction of potential responders to mycophenolate mofetil (MMF), which inhibits de novo but not salvage GMP synthesis. Furthermore, we previously showed that circulating serine uptake is higher in GBM than normal cortex, and a serine- and glycine-restricted diet slows tumor growth in mice. While de novo serine synthesis, circulating and microenvironmental-derived serine could account for serine sources in GBM, our model can distinguish between serine sources in patients, hence potentially predict response to dietary serine depletion. Thus, we have shown that our model may identify patients who will benefit from MMF treatment or a serine- and glycine-restricted diet, potentially enabling administration of highly effective personalized metabolic treatments for GBM patients.

Correlations Between Dietary Magnesium Consumption and Magnesium Depletion Score in Relation to Parkinson's Disease: A Population-Based Study.

The purpose of the study was to examine whether magnesium (Mg) depletion score (MDS) and dietary Mg intake are associated in adults with the risk of developing Parkinson's disease (PD). In this study, we analyzed data from the National Health and Nutrition Examination Survey (NHANES), which included 20,010 adults aged over 40 years old. To evaluate the linear association between PD and dietary intake of Mg or MDS, we conducted weighted logistic regression for univariate analysis and multivariate linear regression models. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models. A restricted cubic spline (RCS) was drawn to visualize the nonlinear relationship between MDS/dietary Mg intake and PD. In addition, we examined the variations in the relationship between MDS and PD across different confounding factors of the association using subgroup analysis. There were 240 PD cases (1.2%), and 19770 non-PD were included in the study. We found that a higher MDS was associated with an increased risk of PD after adjusting for covariates (OR per 1-unit increase, 1.47; 95% CI, 1.16-1.86). There is insufficient evidence to support a significant statistical association between Mg intake and the risk of PD. According to nonlinear regression, high MDS was associated with higher odds of PD and lower odds of PD above 250 mg/day intake of Mg. It has been shown that Mg bioavailability may be negatively associated with PD as measured by MDS. MDS is a potential method for screening the population with PD. Maintaining adequate Mg status may be important for PD prevention.

70 Determination of phosphorus release of Microtech phytase in nursery pig diets

Abstract A total of 320 barrows (DNA 241 × 600; initially 10.7 ± 0.21 kg) were used in a 21-d growth trial to determine the available P (aP) release curve for Microtech phytase (Guangdong VTR Bio-Tech Co, Ltd. Zhuhai, Guangdong, China). At approximately 21 d of age, pigs were weaned and randomly allocated to pens and fed a common diet for 18 d and then fed a P depletion diet (0.11% aP) for 3 d. On d 21 post-weaning, considered d 0 of the study, pigs were blocked by average pen body weight (BW) and randomly allotted to 1 of 8 dietary treatments with 5 pigs per pen and 8 pens per treatment. Dietary treatments were derived from a single basal diet and ingredients including phytase, monocalcium P, limestone, and sand were added to create the treatment diets. Treatments include 3 diets with increasing aP (0.11, 0.19 and 0.27%) using monocalcium phosphate that were used to develop the standard curve and 5 diets with 0.11% aP and increasing phytase (250, 500, 1,000, 1,500 and 2,000 FTU/kg) that were used to develop the aP release curve. Pigs were weighed weekly and feed disappearance was recorded per pen for the calculation of average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F). At the conclusion of the experiment, 1 pig, closest to the mean weight of each pen, was euthanized for bone analysis. The right fibula, rib, and metacarpal were collected for the determination of bone density, bone ash weight, and bone ash percentage. Pigs fed diets with increasing aP from inorganic P had improved (quadratic, P ≤ 0.05) final BW, ADG, and G:F (Table). Pigs fed diets with increasing phytase had linearly increased (P < 0.01) final BW and ADFI and quadratically increased (P ≤ 0.04) ADG and G:F. Bone density, bone ash weight, and bone ash percentage increased linearly (P < 0.01) with increasing aP from inorganic P and increasing phytase. Results were used to determine release values for Microtech phytase for each response criteria as shown in the table. The aP release quadratically increased (P ≤ 0.02) with increasing phytase when growth performance was used as response criteria and linearly increased (P < 0.01) when bone characteristics were used as response criteria. The available P release curve developed for Microtech phytase for percentage bone ash using combined data generated from all three bones is: aP = (0.868 × FTU/kg) ÷ (9,599.511 + FTU/kg).

43 Evaluating the effects of HiPhorius phytase added in diets at or below the P requirement on nursery pig growth performance and bone mineralization

Abstract A total of 297 pigs (DNA 241 × 600; initial body weight = 8.64 ± 0.181 kg) were used in a 21-d trial to evaluate the effects of HiPhorius phytase (dm-firmenich, Parsippany, NJ) on pig growth performance and bone mineralization. All pigs were fed P depletion diets (0.09% aP) for a 3-d period before the start of the study (d 14 after weaning). Pens of pigs were then assigned to 1 of 5 treatments in a randomized complete block design with 5 pigs per pen and 12 replications per treatment. The first three diets were formulated to contain 0.09% aP; without added phytase (control), or control with 600 or 1,000 FYT/kg of added phytase (considering a release of 0.15 or 0.18% aP, respectively). The remaining two diets were formulated to contain 0.27% aP, one without added phytase and the other with 1,000 FYT/kg. One pig per pen was euthanized on d 21 and the right fibula, 10th rib, and metacarpal were collected to determine bone density, bone ash, and bone Ca and P. From d 0 to 21, increasing phytase in diets containing 0.09% aP increased (linear, P ≤ 0.002) average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) and increased percentage bone ash in metacarpals and 10th ribs (linear, P < 0.001; quadratic, P = 0.004, respectively), and increased grams of Ca and P in all three bones (linear, P ≤ 0.027; Table). Adding 1,000 FYT/kg in diets with 0.27% aP did not impact growth performance, but increased percentage bone ash (P ≤ 0.038) in all bones and grams of Ca and P in fibulas and 10th ribs (P ≤ 0.023) compared with pigs fed 0.27% aP without added phytase. Increasing aP from 0.09% to 0.27% in diets without added phytase increased (P < 0.001) ADG, ADFI, and G:F and increased bone density (P ≤ 0.002) in fibulas and metacarpals, percentage bone ash in all bones (P ≤ 0.074), and increased (P < 0.05) grams of Ca and P in fibulas and 10th ribs. Increasing aP from 0.09 to 0.27% aP in diets with 1,000 FYT added phytase increased bone density (P ≤ 0.008) in fibulas and metacarpals, percentage bone ash in all bones (P ≤ 0.002), and grams of Ca and P in fibulas and 10th ribs (P < 0.05). For growth performance (average of ADG and G:F), aP release was calculated to be 0.170% for 600 FYT/kg and 0.206% for 1,000 FYT/kg. For the average of all 3 bone measurements (average of 3 bones for bone density and percentage bone ash), aP release was calculated to be 0.120% and 0.125% for 600 and 1,000 FYT/kg, respectively.

Abstract 1789: Machine learning-based method to analyze metabolic fluxes of patient tumors

Abstract Personalized oncology must overcome the complex challenge of distinct cancer phenotypes in each patient, formed in part in response to unique metabolic crosstalk among cells in the tumor microenvironment which can be a determining factor in therapeutic response. Although isotope tracing sheds light on differences of metabolite enrichments in tumor and normal tissues, quantifying the metabolic fluxes in patients remains elusive. The conventional metabolic flux analysis tools are unable to estimate patient metabolic fluxes because we are limited to a single time point enrichment datapoint from each patient’s in-vivo measurement at isotopic non-steady state. We overcame this challenge by generating training data from the limited patient data and implementing a machine learning model to predict fluxes. To generate training data, we first simulated constrained random fluxes and enrichment patterns at different time points using patient circulating metabolites enrichment via an isotopic non-stationary metabolic flux analysis framework. Using this data, we trained a convolutional neural network to predict flux ratios. To validate our model, we compared predicted flux ratios to the experimental data from mouse models for two different treatments. Our recent findings from a glioblastoma (GBM) mouse model study using conventional metabolic flux analysis revealed higher de novo guanosine monophosphate (GMP) synthesis in GBM than normal cortex. These tumors can be sensitive to mycophenolate mofetil (MMF) which inhibits inosine monophosphate dehydrogenase, but only if the major source of GMP production is de novo synthesis and not salvage. Our machine learning model can discriminate between sources of GMP synthesis in patients, thus enabling prediction of potential responders. Furthermore, we previously showed that serine uptake is higher in GBM than normal cortex, and a serine- and glycine-restricted diet slows tumor growth in mice. While both circulating serine and microenvironment-derived serine could account for serine uptake in GBM, we hypothesized that the circulating serine dependence would better predict response to dietary serine depletion. Hence, we combined patient scRNA-seq and metabolomics data to feed our neural network framework to estimate microenvironmental and circulating serine uptake in six patients with brain cancer. Thus, we have shown that our model can identify patients who will benefit from MMF treatment or a serine- and glycine-restricted diet, enabling administration of highly effective personalized treatments for GBM patients. Citation Format: Baharan Meghdadi, Anjali Mittal, Andrew J. Scott, Sravya Palavalasa, Daniel R. Wahl, Deepak Nagrath. Machine learning-based method to analyze metabolic fluxes of patient tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1789.

Abstract B050: Metabolic rewiring in human brain cancer

Abstract Metabolic adaptation can promote oncogenic phenotypes in glioblastoma (GBM), but the metabolic pathways utilized by GBM and how they differ from the pathways utilized in normal cortex are poorly understood. Here, we utilize in vivo stable isotope tracing in mice and patients with glioblastoma to define carbon fate and metabolic rewiring in cancer. We infused uniformly labeled 13C glucose into mice bearing orthotopic GBM patient-derived xenografts or into patients undergoing surgical resection for likely GBM. Tumor and cortex were physically separated in mice by fluorescence-guided microdissection. In humans, samples of enhancing tumor, non-enhancing tumor and normal cortex were separated intraoperatively using MRI guidance. Samples were subsequently analyzed by liquid chromatography mass spectrometry and MALDI imaging mass spectrometry to determine the downstream metabolic fates of infused 13C glucose. Of eight patients infused with 13C6-glucose, six were confirmed to have GBM while the others had non-GBM high grade gliomas. In mice and in patients, glucose-derived carbon effectively entered glycolysis and labeled glycolytic intermediates equivalently in tumor and cortex. Compared to GBM tissue, cortical tissue preferentially oxidized glucose-derived carbon in the TCA cycle and used glucose-derived carbon to synthesize the neurotransmitter GABA. Cortical tissue utilized glucose-derived carbon to synthesize the amino acid and neurotransmitter precursor serine, while GBM tissue preferentially derived serine from extracellular sources. By contrast, GBM preferentially utilized glucose-derived carbon for the synthesis of metabolites required for growth: purines, pyrimidines and NAD+/NADH. These studies are the first measurements of numerous metabolic pathways in human brain cancer and cortex and suggest that GBMs suppress the physiologic utilization of glucose carbons for ATP and neurotransmitter generation and instead use these carbons to synthesize the biomolecules they need to proliferate. Consistent with this hypothesis, eliminating dietary serine in mice slowed GBM PDX growth and forced tumors to synthesize serine from glucose, which in turn lowered tumor nucleotide and NAD+/NADH levels. Dietary serine depletion had minimal effects on cortical metabolism, consistent with glucose being the primary serine source in the normal brain. These direct measurements of metabolic pathway activity in human and mouse brain cancer reveal adaptive metabolic rewiring and new therapeutic targets. Citation Format: Andrew Scott, Anjali Mittal, Sravya Palavalasa, Baharan Meghdadi, Nathan Qi, Alexandra O'Brien, Ayesha Kothari, Nathalie Agar, Ethan Yang, Joshua Fischer, Vijay Tarnal, Wajd Al-Holou, Costas Lyssiotis, Deepak Nagrath, Daniel Wahl. Metabolic rewiring in human brain cancer [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr B050.

Retinoic acid modulation of granule cell activity and spatial discrimination in the adult hippocampus.

Retinoic acid (RA), derived from vitamin A (retinol), plays a crucial role in modulating neuroplasticity within the adult brain. Perturbations in RA signaling have been associated with memory impairments, underscoring the necessity to elucidate RA's influence on neuronal activity, particularly within the hippocampus. In this study, we investigated the cell type and sub-regional distribution of RA-responsive granule cells (GCs) in the mouse hippocampus and delineated their properties. We discovered that RA-responsive GCs tend to exhibit a muted response to environmental novelty, typically remaining inactive. Interestingly, chronic dietary depletion of RA leads to an abnormal increase in GC activation evoked by a novel environment, an effect that is replicated by the localized application of an RA receptor beta (RARβ) antagonist. Furthermore, our study shows that prolonged RA deficiency impairs spatial discrimination-a cognitive function reliant on the hippocampus-with such impairments being reversible with RA replenishment. In summary, our findings significantly contribute to a better understanding of RA's role in regulating adult hippocampal neuroplasticity and cognitive functions.

Inulin Supplementation Modulates the Hepatic Transcriptome, Metabolome, and Ferritin Content in Ovariectomized Rats.

Liver is an important metabolic organ regulating whole-body homeostasis. This study aims to investigate how prebiotic-induced changes in the metabolic activity of the gut microbiome (GM) and dietary calcium depletion modulates the hepatic metabolome and transcriptome. The serum metabolome, liver metabolome, and transcriptome are determined on samples from ovariectomized (OVX) rats fed a control diet (Control, n = 7), a control diet supplemented with 5% w/w inulin (Inulin, n = 7), or a calcium-deficient diet (CaDef, n = 7). Inulin fortification is associated with higher serum concentrations of acetate, 3-hydroxybutyrate, and reduced concentration of dimethyl sulfone, revealing that changes in the metabolic activity of the GM are reflected in circulating metabolites. Metabolomics also reveal that the inulin-fortified diet results in lower concentrations of hepatic glutamate, serine, and hypoxanthine while transcriptomics reveal accompanying effects on the hepatic expression of ferric iron binding-related genes. Inulin fortification also induces effects on the hepatic expression of genes involved in olfactory transduction, suggesting that prebiotics regulate liver function through yet unidentified mechanisms involving olfactory receptors. Inulin ingestion impacts hepatic gene expression and is associated with an upregulation of ferritin synthesis-related genes and liver ferritin content.

Microglia preserve visual function in the aging retina by supporting retinal pigment epithelial health

BackgroundIncreased age is a risk factor for the development and progression of retinal diseases including age-related macular degeneration (AMD). Understanding the changes that occur in the eye due to aging is important in enhancing our understanding of AMD pathogenesis and the development of novel AMD therapies. Microglia, the resident brain and retinal immune cells are associated with both maintaining homeostasis and protection of neurons and loss of microglia homeostasis could be a significant player in age related neurodegeneration. One important characteristic of retinal aging is the migration of microglia from the inner to outer retina where they reside in the subretinal space (SRS) in contact with the retinal pigment epithelial (RPE) cells. The role of aged subretinal microglia is unknown. Here, we depleted microglia in aged C57/BL6 mice fed for 6 weeks with a chow containing PLX5622, a small molecule inhibitor of colony-stimulating factor-1 receptor (Csf1r) required for microglial survival.ResultsThe subretinal P2RY12 + microglia in aged mice displayed a highly amoeboid and activated morphology and were filled with autofluorescence droplets reminiscent of lipofuscin. TEM indicates that subretinal microglia actively phagocytize shed photoreceptor outer segments, one of the main functions of retinal pigmented epithelial cells. PLX5622 treatment depleted up to 90% of the retinal microglia and was associated with significant loss in visual function. Mice on the microglia depletion diet showed reduced contrast sensitivity and significantly lower electroretinogram for the c-wave, a measurement of RPE functionality, compared to age-matched controls. The loss of c-wave coincided with a loss of RPE cells and increased RPE swelling in the absence of microglia.ConclusionsWe conclude that microglia preserve visual function in aged mice and support RPE cell function, by phagocytosing shed photoreceptor outer segments and lipids, therefore compensating for the known age-related decline of RPE phagocytosis.

Regulation of human salt-sensitivite hypertension by myeloid cell renin-angiotensin-aldosterone system.

Introduction: Salt sensitivity of blood pressure is a phenomenon in which blood pressure changes according to dietary sodium intake. Our previous studies found that high salt activates antigen presenting cells, resulting in the development of hypertension. The mechanisms by which salt-induced immune cell activation is regulated in salt sensitivity of blood pressure are unknown. In the current study, we investigated dietary salt-induced effects on the renin-angiotensin-aldosterone system (RAAS) gene expression in myeloid immune cells and their impact on salt sensitive hypertension in humans. Methods: We performed both bulk and single-cell sequencing analysis on immune cells with in vitro and in vivo high dietary salt treatment in humans using a rigorous salt-loading/depletion protocol to phenotype salt-sensitivity of blood pressure. We also measured plasma renin and aldosterone using radioimmunoassay. Results: We found that while in vitro high sodium exposure downregulated the expression of renin, renin binding protein and renin receptor, there were no significant changes in the genes of the renin-angiotensin system in response to dietary salt loading and depletion in vivo. Plasma renin in salt sensitive individuals tended to be lower with a blunted response to the salt loading/depletion challenge as previously reported. Discussion: These findings suggest that unlike systemic RAAS, acute changes in dietary salt intake do not regulate RAAS expression in myeloid immune cells.

Vitamin D deficiency contributes to overtraining syndrome in excessive trained C57BL/6 mice.

Overtraining syndrome is a condition resulting from excessive training load associated with inadequate recovery and poor sleep quality, leading to performance decrements and fatigue. Here we hypothesized that vitamin D (VitD) deficiency is a lead factor in the development of the overtraining syndrome. To test this hypothesis, two groups of 60-week-old C57BL/6 mice followed a 16-week excessive eccentric-based overtraining by excessive downhill running with or without dietary VitD depletion (EX and EX-D- groups). Two control groups were trained by uphill running at the same load with or without VitD depletion (CX and CX-D- groups). Handgrip strength decreased throughout the protocol for all groups but the decrease was sharper in EX-D- group (VitD × training, p = 0.0427). At the end of the protocol, the mass of Triceps brachii muscle, which is heavily stressed by eccentric contractions, was reduced in eccentric-trained groups (training effect, p = 0.0107). This atrophy was associated with a lower concentration of the anabolic myokine IL-15 (training effect, p = 0.0314) and a tendency to a higher expression of the atrogene cathepsin-L (training effect, p = 0.0628). VitD depletion led to a 50% decrease of the fractional protein synthesis rate in this muscle (VitD effect, p = 0.0004) as well as decreased FGF21 (VitD effect, p = 0.0351) and increased osteocrin (VitD effect, p = 0.038) concentrations that would lead to metabolic defects. Moreover, the proportion of anti-inflammatory Th2 lymphocytes was significantly decreased by the combination of eccentric training with VitD depletion (vitD × training, p = 0.0249) suggesting a systemic inflammation. Finally, exploratory behavior time of mice was decreased by VitD depletion (VitD effect, p = 0.0146) suggesting a cognitive dysfunction. Our results suggest that VitD deficiency exacerbates the effects of overtraining.

On the haem auxotrophy of the soft tick Ornithodoros moubata

Genomes of ticks display reductions, to various extents, in genetic coding for enzymes of the haem biosynthetic pathway. Here, we mined available transcriptomes of soft tick species and identified transcripts encoding only half of the enzymes involved in haem biosynthesis. Transcripts identified across most species examined were those coding for porphobilinogen synthase, coproporphyrinogen oxidase, protoporphyrinogen oxidase, and ferrochelatase. Genomic retention of porphobilinogen synthase seems to be soft tick-restricted as no such homologue has been identified in any hard tick species. Bioinformatic mining is thus strongly indicative of the lack of biochemical capacity for de novo haem biosynthesis, suggesting a requirement for dietary haem. In the hard tick Ixodes ricinus, depletion of dietary haem, i.e. serum feeding, leads to oviposition of haem-free eggs, with no apparent embryogenesis and larvae formation. In this work, we show that serum-fed Ornithodoros moubata females, unlike those of I. ricinus, laid haem-containing eggs similarly to blood-fed controls, but only by a small proportion of the serum-fed females. To enhance the effect of dietary haem depletion, O. moubata ticks were serum-fed consecutively as last nymphal instars and females. These females laid eggs with profoundly reduced haem deposits, confirming the host origin of the haem. These data confirm the ability of soft ticks to take up and allocate host haem to their eggs in order to drive reproduction of the ticks.

Unexpected Absence of Skeletal Responses to Dietary Magnesium Depletion: Basis for Future Perspectives?

It's known that a magnesium (Mg)-deficient diet is associated with an increased risk of osteoporosis. The aim of this work is to investigate, by a histological approach, the effects of a Mg-deprived diet on the bone of 8-weeks-old C57BL/6J male mice. Treated and control mice were supplied with a Mg-deprived or normal diet for 8 weeks, respectively. Body weight, serum Mg concentration, expression of kidney magnesiotropic genes, and histomorphometry on L5 vertebrae, femurs, and tibiae were evaluated. Body weight gain and serum Mg concentration were significantly reduced, while a trend toward increase was found in gene expression in mice receiving the Mg-deficient diet, suggesting the onset of an adaptive response to Mg depletion. Histomorphometric parameters on the amount of trabecular and cortical bone, number of osteoclasts, and thickness of the growth plate in femoral distal and tibial proximal metaphyses did not differ between groups; these findings partially differ from most data present in the literature showing that animals fed a Mg-deprived diet develop bone loss and may be only in part explained by differences among the experimental protocols. However, the unexpected findings we recorded on bones could be attributed to genetic differences that may have developed after multiple generations of inbreeding.

Genome-Wide CRISPR/Cas9 Library Screening Revealed Dietary Restriction of Glutamine in Combination with Inhibition of Pyruvate Metabolism as Effective Liver Cancer Treatment.

Hepatocellular carcinoma (HCC) is the second most lethal cancer worldwide. Glutamine is an essential, extracellular nutrient which supports HCC growth. Dietary glutamine deficiency may be a potential therapeutic approach for HCC. HCC cells overcome metabolic challenges by rewiring their metabolic pathways for rapid adaptations. The efficiency of dietary glutamine deficiency as HCC treatment is examined and the adaptation machinery under glutamine depletion in HCC cells is unraveled. Using genome-wide CRISPR/Cas9 knockout library screening, this study identifies that pyruvate dehydrogenase α (PDHA), pyruvate dehydrogenase β (PDHB), and pyruvate carboxylase (PC) in pyruvate metabolism are crucial to the adaptation of glutamine depletion in HCC cells. Knockout of either PDHA, PDHB or PC induced metabolic reprogramming of the tricarboxylic acid (TCA) cycle, disrupts mitochondrial function, leading to the suppression of HCC cell proliferation under glutamine depletion. Surprisingly, dietary glutamine restriction improves therapeutic responses of HCC to PDH or PC inhibitor in mouse HCC models. Stable isotope carbon tracing confirms that PDH or PC inhibitors further disrupt the metabolic rewiring of the TCA cycle induced by dietary glutamine depletion in HCC. In summary, the results demonstrate that pyruvate metabolism acts as novel targetable metabolic vulnerabilities for HCC treatment in combination with a glutamine-deficient diet.

Associations of the Dietary Magnesium Intake and Magnesium Depletion Score With Osteoporosis Among American Adults: Data From the National Health and Nutrition Examination Survey.

ObjectivesThe study aimed to explore the associations between dietary magnesium (Mg) intake and magnesium depletion score (MDS) among American adults with osteoporosis.MethodsThe continuous data from the National Health and Nutrition Examination Survey 2005–2006, 2007–2008, 2009–2010, 2013–2014, and 2017–2018 were merged to ensure a large and representative sample and a total of 14,566 participants were enrolled for the analysis. The weighted multivariate linear regression model was performed to assess the linear relationship between dietary Mg intake and osteoporosis. Further, the non-linear relationship was also characterized by smooth curve fitting (SCF) and weighted generalized additive model (GAM). In addition, the odds ratios (ORs) and 95% confidence intervals (95% CIs) for associations between the MDS and osteoporosis were assessed by weighted logistic regression models.ResultsAfter adjusting all covariates, the weighted multivariable linear regression models demonstrated that the dietary Mg intake negatively correlated with osteoporosis, especially in participants aged 55 years or older. In addition, the non-linear relationship characterized by SCF and weighted GAM showed that the dietary Mg intake presented an L-shaped association with osteoporosis among females aged 55 years or older. Moreover, the weighted logistic regression model demonstrated that compared with MDS 0, the OR between MDS ≥3 and osteoporosis was 2.987 (95% CI 1.904, 4.686) in the male-middle intake group. Moreover, compared with MDS 0, the ORs between MDS ≥3 and osteoporosis was 5.666 (95% CI 3.188, 10.069) in the female-low intake group and 1.691 (95% CI 1.394, 2.051) in the female-middle intake group.ConclusionThe present study indicated that in people with a daily intake of Mg level below the recommended daily intake (RDI), the dietary Mg intake and Mg bioavailability represented by MDS have a negative correlation with osteoporosis. According to the results, the combination of MDS and dietary Mg intake may be more comprehensive and rigorous in screening the population with osteoporosis. Therefore, early monitoring and interventions for osteoporosis may be necessary for those with insufficient dietary Mg intake or high MDS scores.

Dietary Indole‐3‐Carbinol Supplementation Restores Epithelial Abnormalities in SAMP1/YitFc Mouse Model of Ileitis

SAMP1/YitFC (SAMP) mice exhibit spontaneous ileitis as they age with morphological and functional epithelial abnormalities mimicking human Crohn’s disease, a chronic disease characterized by ileal inflammation. Indole‐3‐carbinole (I3C), found in broccoli and Brussel sprouts, plays a crucial role in the anti‐inflammatory processes by activating the aryl hydrocarbon receptor (AhR), a transcription factor vital for epithelial and immune cell functions. The impact of I3C diet on disease progression and epithelial integrity in SAMP model of ileitis is not known.Methods6‐week‐old male and female (n=8 per group) SAMP and control AKR/J mice (Jackson) were fed for 14 weeks either a standard chow diet or a purified diet supplemented with 200 ppm with indole‐3‐carbinole (+I3C diet), or purified diet depleted of AhR ligands (‐I3C diet). Ileum samples were collected for qPCR and histological analyses. Statistical analysis was performed by Tukey’s multiple comparison test for all three diets. To detect changes between +I3C vs. ‐I3C, delta values (Δ +/‐I3C = SAMP‐AKR) were analyzed by unpaired T‐test.ResultsAs expected, H&E staining for the ileum of SAMP mice fed chow diet, showed thickening of the muscle layer, neutrophil infiltration, and epithelial tufting vs. AKR mice. Severity of inflammation in SAMP mice, as assessed by fecal calprotectin ELISA, mRNA expression of cytokines, and histological analysis was not significantly impacted by dietary depletion or supplementation of I3C. With respect to epithelial abnormalities, Periodic Acid Schiff staining showed increased number of goblet cells per villi (~47‐75%) in SAMP mice on all three diets. While mRNA levels of the major goblet cell secretory proteins, mucin2 (Muc2) and intestinal trefoil factor (ITF), were dramatically decreased in SAMP mice vs. AKR, supplementation of I3C attenuated this decrease in Muc2 and ITF by ~35% and 51% (p<.001), respectively, indicating defective synthesis or secretion. Similarly, I3C diet significantly (p<.01) attenuated the decrease in Paneth cell markers lysozyme C‐1 (LYZ1) alpha defensin 5 (Def5α) and regenerating islet‐derived protein 3 alpha (Reg3α) in SAMP mice by ~65%, 60%, and 24%, respectively. A decrease in fibroblast growth factor 15 (FGF15) and the epithelial ion transporters serotonin transporter (SERT) and organic solute transporter (OST) were observed in ileal mucosa of SAMP mice vs. AKR, and the supplementation of I3C mitigated these decreases by 30‐58% (p<.01). There were no significant changes in the expression of tryptophan hydroxylase 1 (tph‐1), C‐X‐C motif chemokine ligand 2 (CXCL2), or AhR by I3C diet in SAMP mice. In summary, I3C supplementation significantly attenuated the goblet cell, Paneth cell, and epithelial‐specific abnormalities seen in SAMP mice. These data imply that dietary supplementation of AhR ligands may be a viable therapeutic strategy for Crohn’s patients to restore epithelial integrity.

Development of bone mineralization and body composition of replacement gilts fed a calcium and phosphorus depletion and repletion strategy

This study investigated the ability of replacement gilts to adapt their calcium and phosphorus utilization and their kinetics in bone mineralization to compensate for modified intake of these nutrients by applying a novel Ca and P depletion and repletion strategy. A total of 24 gilts were fed according to a two-phase feeding program. In the first phase, gilts (60–95 kg BW) were fed ad libitum a depletion diet providing either 60% (D60; 1.2 g digestible P/kg) or 100% (D100; 2.1 g digestible P/kg) of the estimated P requirement. In the second phase, gilts (95–140 kg BW) were fed restrictively (aim: 700–750 g/d BW gain) a repletion diet. Half of the gilts from each depletion diet were randomly assigned to either a control diet or a high-P diet (R100 and R160; with 2.1 and 3.5 g digestible P/kg, respectively) according to a 2 × 2 factorial design, resulting in four treatments: D60-R100, D60-R160, D100-R100 and D100-R160. Dual-energy X-ray absorptiometry was used to measure whole-body bone mineral content (BMC), bone mineral density (BMD) and lean and fat tissue mass on each gilt at 2-week intervals. The depletion and repletion diets, fed for 5 and 8 weeks, respectively, did not influence growth performance. The D60 gilts had a reduced BMC and BMD from the second week onwards and ended (95 kg BW) with 9% lower values than D100 gilts (P < 0.001). During repletion, D60 gilts completely recovered the deficit in bone mineralization from the second and fourth week onwards, when fed R160 (D60-R160 vs D100-R160) or R100 (D60-R100 vs D100-R100) diets, respectively (treatment × time interaction, P < 0.001); thus, the depletion diets did not affect these values at 140 kg BW. These results illustrate the rapid homeostatic counter-regulation capacity of dietary Ca and P, and they show the high potential to limit dietary digestible P concentration by completely excluding the use of mineral phosphates during the depletion phase, representative of the fattening period, without causing any detrimental effects to gilts at mating. The gilts were able to recover their BMC deficit between their selection at 95 kg BW and first mating at 140 kg BW by increasing their dietary Ca and P efficiency. Finally, excess dietary digestible P, requiring increased amounts of mineral phosphates, further increased the gilts’ BMC.

63 Effects of Dietary Calcium and Phosphorus Deficiency on Growth Performance and Subsequent Recovery of Bone Mineralization in Replacement Gilts

Abstract This study was performed to test the hypothesis that after a depletion period that renders replacement gilts more efficient in their use of calcium (Ca) and phosphorus (P), they can recover bone mineralization when fed a repletion diet. To this end, 24 gilts were fed according to a 2-phase feeding program (60–95 kg BW and 95–140 kg BW, respectively), corresponding to the period of depletion and repletion in Ca and P, respectively. The experimental diets for the first phase were a finisher control diet (D100; 2.1 g digestible P/kg) providing 100% of estimated Ca and P requirements or a finisher low-P diet (D60; 1.2 g digestible P/kg) providing 60% of estimated Ca and P requirements. In the second phase, one-half of the gilts from each finisher diet were randomly assigned to either a control (R100) diet or a high-P diet (R160; 3.5 g digestible P/kg) according to a 2 × 2 factorial design, resulting in 4 treatments: D60R100, D60R160, D100R100 and D100R160. Whole-body bone mineral content (BMC) and body composition of pigs were measured on each gilt at 2-week intervals by dual energy X-ray absorptiometry. Diets did not influence the growth performance throughout the experiment. At 95 kg, gilts fed D60 had reduced BMC and BMD (-9% vs D100; P &amp;lt; 0.001). At 140 kg, no significant effect of depletion diets was observed on BMC. These results show the high potential to limit dietary digestible P concentration during the growing period without causing any detrimental effects to gilts at mating, and they confirm the ability of replacement gilts to recover their BMC at 140 kg BW by increasing BMC deposition and their dietary Ca and P efficiency. Finally, high-digestible P content from 95-140 kg BW allowed gilts to increase BMC further, but required the use of dietary phosphates.

Milk exosomes in nutrition and drug delivery.

Exosomes are natural nanoparticles that originate in the endocytic system. Exosomes play an important role in cell-to-cell communication by transferring RNAs, lipids, and proteins from donor cells to recipient cells or by binding to receptors on the recipient cell surface. The concentration of exosomes and the diversity of cargos are high in milk. Exosomes and their cargos resist degradation in the gastrointestinal tract and during processing of milk in dairy plants. They are absorbed and accumulate in tissues following oral administrations, cross the blood-brain barrier, and dietary depletion and supplementation elicit phenotypes. These features have sparked the interest of the nutrition and pharmacology communities for exploring milk exosomes as novel bioactive food compounds and for delivering drugs to diseased tissues. This review discusses the current knowledgebase, uncertainties, and controversies in these lines of scholarly endeavor and health research.

Preliminary evidence that lectins in infant soy formula apparently bind bovine milk exosomes and prevent their absorption in healthy adults

BackgroundMilk exosomes and their microRNA (miR) cargos are bioavailable. The content of exosomes and miRs is negligible in infant formulas compared to human milk, and dietary depletion of exosomes led to changes in bacterial communities and impaired gut health in juvenile mice. Adverse effects of formula feeding may be compounded by using soy formulas due to exosome binding by abundant lectins in that matrix. The purpose of this study was to assess the bioavailability of milk exosomes and their miR cargos added to soy formula in adults, as well as the potential role of soy lectins in exosome bioavailability.MethodsEleven healthy adults (6 men, 5 women) enrolled in this randomized crossover study. Participants consumed 1.0 l of soy formula without (SF) or with (SFE) bovine milk exosomes added. Concentration-time curves of six plasma miRs were analyzed using reverse transcription quantitative PCR. Lectin affinity chromatography was used to assess the binding of exosomes by soy lectins. Data were analyzed by using paired t test. P < 0.05 was considered statistically significant.ResultsConsumption of SF and SFE did not elicit postprandial increases in plasma miRs. Approximately 39% of bovine milk exosome particles were retained by lectin columns.ConclusionsWe conclude that fortification of soy formulas with milk exosomes, in the absence of removing lectins, is not a viable strategy for delivering bioavailable exosomes and their miR cargos. Lectins in soy formulas bind glycoprotein on the surfaces of milk exosomes, thereby preventing exosome absorption.Trial registrationISRCTN registry ID: 16329971. Retrospectively registered on February 7th, 2019.