Calcium-deficiency assessment and biomarker identification by an integrated urinary metabonomics analysis

Effects of Menaquinone-7 on the Bone Health of Growing Rats under Calcium Restriction: New Insights from Microbiome-Metabolomics

Insufficient calcium intake during growth is a global public health concern. The aim of this study was to investigate the effects of dietary menaquinone-7 (MK-7) on bone accrual in growing Sprague-Dawley rats under calcium restriction. Following 13 weeks of treatment, various bone quality parameters, including microarchitecture, were measured. Fecal and cecal samples were subjected to microbiome (16S rRNA gene sequencing) analyses, while metabolomics analysis of the cecum and humerus samples was analyzed based on UHPLC-Q/TOF-MS. We found that calcium deficiency diminished the richness of the microbiome and disrupted microbiome composition, accompanied by an elevation in the relative abundance of Parasutterella. Furthermore, calcium insufficiency escalated the level of isovaleric acid and modified the metabolic profiles. MK-7 supplementation significantly increased the cortical thickness, cortical bone area, and the calcium content of the femur. Apart from improving bone calcium deposition and diminishing bone resorption, the mechanisms underlying the beneficial effects of MK on bone quality also involve the modulation of the host's metabolic pathways and the composition of gut microbiota. The gut-bone axis holds promise as an efficacious target for ameliorating calcium deficiency in children's bone quality, and MK-7 is a promising dietary supplement from this perspective.

Chondroitin sulfate alleviates osteoporosis caused by calcium deficiency by regulating lipid metabolism

The use of non-drug intervention for calcium deficiency has attracted attention in recent years. Although calcium carbonate is the preferred raw material for calcium supplementation, there are few reports on the mechanism of the combined action of chondroitin sulfate and calcium to alleviate osteoporosis from the perspective of gut microbiota and metabolomics. In this study, a rat model of osteoporosis was established by feeding a low-calcium diet. The intestinal microbiota abundance, fecal and plasma metabolite expression levels of rats fed a basal diet, a low-calcium diet, a low-calcium diet plus calcium carbonate, and a low-calcium diet plus chondroitin sulfate were compared. The results showed that compared with the low calcium group, the calcium content and bone mineral density of femur were significantly increased in the calcium carbonate and chondroitin sulfate groups. 16 S rRNA sequencing and metabolomics analysis showed that chondroitin sulfate intervention could reduce short-chain fatty acid synthesis of intestinal flora, slow down inflammatory response, inhibit osteoclast differentiation, promote calcium absorption and antioxidant mechanism, and alleviate osteoporosis in low-calcium feeding rats. Correlation analysis showed that the selected intestinal flora was significantly correlated with metabolites enriched in feces and plasma. This study provides scientific evidence of the potential impact of chondroitin sulfate as a dietary supplement for patients with osteoporosis.

Applications of Metabolomics in Calcium Metabolism Disorders in Humans

The pathogenesis of the disorders of calcium metabolism is not fully understood. This review discusses the studies in which metabolomics was applied in this area. Indeed, metabolomics could play an essential role in discovering biomarkers and elucidating pathological mechanisms. Despite the limited bibliography, the present review highlights the potential of metabolomics in identifying the biomarkers of some of the most common endocrine disorders, such as primary hyperparathyroidism (PHPT), secondary hyperparathyroidism (SHPT), calcium deficiency, osteoporosis and vitamin D supplementation. Metabolites related to above-mentioned diseorders were grouped into specific classes and mapped into metabolic pathways. Furthermore, disturbed metabolic pathways can open up new directions for the in-depth exploration of the basic mechanisms of these diseases at the molecular level.

Free Zinc as a Predictive Marker for COVID-19 Mortality Risk

Free zinc is considered to be the exchangeable and biological active form of zinc in serum, and is discussed to be a suitable biomarker for alterations in body zinc homeostasis and related diseases. Given that coronavirus disease 2019 (COVID-19) is characterized by a marked decrease in total serum zinc, and clinical data indicate that zinc status impacts the susceptibility and severity of the infection, we hypothesized that free zinc in serum might be altered in response to SARS-CoV-2 infection and may reflect disease severity. To test this hypothesis, free zinc concentrations in serum samples of survivors and nonsurvivors of COVID-19 were analyzed by fluorometric microassay. Similar to the reported total serum zinc deficit measured by total reflection X-ray fluorescence, free serum zinc in COVID-19 patients was considerably lower than that in control subjects, and surviving patients displayed significantly higher levels of free zinc than those of nonsurvivors (mean ± SD; 0.4 ± 0.2 nM vs. 0.2 ± 0.1 nM; p = 0.0004). In contrast to recovering total zinc concentrations (r = 0.706, p < 0.001) or the declining copper−zinc ratio (r = −0.646; p < 0.001), free zinc concentrations remained unaltered with time in COVID-19 nonsurvivors. Free serum zinc concentrations were particularly low in male as compared to female patients (mean ± SD; 0.4 ± 0.2 nM vs. 0.2 ± 0.1 nM; p = 0.0003). This is of particular interest, as the male sex is described as a risk factor for severe COVID-19. Overall, results indicate that depressed free serum zinc levels are associated with increased risk of death in COVID-19, suggesting that free zinc may serve as a novel prognostic marker for the severity and course of COVID-19.

Two untargeted metabolomics reveals yogurt-associated metabolic alterations in women with multiple metabolic disorders from a randomized controlled study

The beneficial role of yogurt on metabolic profile has been widely reported. Yet, few studies have intended to describe the integrated metabolic alterations in response to yogurt. Yogurt and milk (220 g/d) were given to 48 and 44 obese women with metabolic syndrome and nonalcoholic fatty liver disease for 24 weeks in a randomized controlled trial (registered at http://www.chictr.org.cn as ChiCTR-IPR-15006801). Fasting serum samples were collected before and after intervention for global, untargeted metabolomics based on ¹H nuclear magnetic resonance (NMR) and ultra-high-performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry (UPLC-Q-TOF-MS) (in positive and negative ion modes). Multivariable statistical analysis and pathway analysis were conducted. In both ¹H NMR and UPLC-Q-TOF-MS metabolomics, no clustering was observed between the two groups at baseline. While, a clear clustering was shown after intervention, and the yogurt group had significantly different metabolic status from the milk. The metabolites that contributed mostly to class separation were identified, and involved into pathway analysis. Pathways on amino acids metabolism, fatty acid oxidation, cholesterol catabolism and choline metabolism significantly changed after yogurt intervention. The study revealed the integrated metabolic alterations in response to yogurt via two metabolomics approaches, suggesting the potential mechanisms of yogurt against metabolic disorders. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-IPR-15006801. Registered 20 July 2015, http://www.chictr.org.cn/ ChiCTR-IPR-15006801. SIGNIFICANCE: Both review from prospective studies and our randomized clinical trial showed the protective role of yogurt against multiple metabolic disorders. However, they were focus on targeted glucose, lipid, and other metabolic indicators, which were only part of human metabolism, failing to show an integrated metabolic feature on yogurt. Therefore, two global, untargeted metabolomics were applied in our current randomized clinical trial, trying to uncover the significant metabolic alterations characterizing the effects of yogurt on obese women with multiple metabolic disorders, and to explore the potential biological mechanisms of yogurt. The finding will shed light on a more comprehensive picture of how yogurt affects host metabolism, and provide theoretical foundation for dietary prevention of chronic diseases.

Application of metabolomics in osteoporosis research

Osteoporosis (OP) is a systemic disease characterized by bone metabolism imbalance and bone microstructure destruction, which causes serious social and economic burden. At present, the diagnosis and treatment of OP mainly rely on imaging combined with drugs. However, the existing pathogenic mechanisms, diagnosis and treatment strategies for OP are not clear and effective enough, and the disease progression that cannot reflect OP further restricts its effective treatment. The application of metabolomics has facilitated the study of OP, further exploring the mechanism and behavior of bone cells, prevention, and treatment of the disease from various metabolic perspectives, finally realizing the possibility of a holistic approach. In this review, we focus on the application of metabolomics in OP research, especially the newer systematic application of metabolomics and treatment with herbal medicine and their extracts. In addition, the prospects of clinical transformation in related fields are also discussed. The aim of this study is to highlight the use of metabolomics in OP research, especially in exploring the pathogenesis of OP and the therapeutic mechanisms of natural herbal medicine, for the benefit of interdisciplinary researchers including clinicians, biologists, and materials engineers.

Metabolomics analysis of urine from rats given long-term high-protein diet using ultra-high-performance liquid chromatography-mass spectrometry

Previous studies have indicated high-protein diet (HPD) promotes weight loss and improves metabolic parameters, but most of these studies have focused on the impact of short-term, long-term effects remain unclear. In this study, male Wistar rats were fed two diets for 88 weeks: normal control diet (NCD, 20.5% of energy as protein) or HPD (30.5% of energy as protein). At 88 weeks intervention, compared to NCD rats, HPD rats had lower fat tissue and higher skeletal muscle to body weight ratio, but there were no significantly differences in body weight and food intake. To explore the mechanism underlying metabolism and diet, we further collected rat urine samples at 16, 40, 64 and 88 weeks diet treatment and analyzed metabolomics profiles using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). Partial least squares-discriminant analysis (PLS-DA) scores plots from ESI- or ESI+ model revealed a perfect separation between two diets at four time points. We identified 11 dramatically different metabolites (with VIP cut-off value > 1) in HPD, including 3 up-regulated and 8 down-regulated. And these 11 metabolites were identified as effective biomarkers, which were significantly related to HPD-induced metabolism related outcomes (fat tissue and skeletal muscle to body weight ratio). Our results provided vital information regarding metabolism in long-term HPD and more importantly, a few potentially promising metabolites were firstly identified which may related to metabolic responses.

Concentrations of Ca, Mg, P, Prostaglandin E2 in Bones and Parathyroid Hormone; 1,25-dihydroxyvitamin D3; 17-β-estradiol; Testosterone and Somatotropin in Plasma of Aging Rats Subjected to Physical Training in Cold Water

Exposure to low temperatures can be considered a stressor, which when applied for a specific time can lead to adaptive reactions. In our study we hypothesized that cold, when applied to the entire body, may be a factor that positively modifies the aging process of bones by improving the mechanisms related to the body's mineral balance. Taking the above into account, the aim of the study was to determine the concentration of calcium (Ca), magnesium (Mg), and phosphorus (P) in bones, and to examine bone density and concentrations of the key hormones for bone metabolism, namely parathyroid hormone (PTH), somatotropin (GH), 1,25-dihydroxyvitamin D3, 17-β estradiol, testosterone (T) in plasma, and prostaglandin E2 (PGE2) in the bone of aging rats subjected to physical training in cold water. The animals in the experiment were subjected to a series of swimming sessions for nine weeks. Study group animals (male and female respectively) performed swimming training in cold water at 5 ± 2 °C and in water with thermal comfort temperature (36 ± 2 °C). Control animals were kept in a sedentary condition. Immersion in cold water affects bone mineral metabolism in aging rats by changing the concentration of Ca, Mg, and P in the bone, altering bone mineral density and the concentration of key hormones involved in the regulation of bone mineral metabolism. The effect of cold-water immersion may be gender-dependent. In females, it decreases Ca and Mg content in bones while increasing bone density and 17-β estradiol and 1,25-dihydroxyvitamin D3 levels, and with a longer perspective in aging animals may be positive not only for bone health but also other estrogen-dependent tissues. In males, cold water swimming decreased PTH and PGE2 which resulted in a decrease in phosphorus content in bones (with no effect on bone density), an increase in 1,25-dihydroxyvitamin D3, and increase in T and GH, and may have positive consequences especially in bones and muscle tissue for the prevention of elderly sarcopenia.

Integrated multi-omics uncovers reliable potential biomarkers and adverse effects of zinc deficiency

BACKGROUND

Zinc deficiency is a worldwide public health problem. Currently, there are no established biomarkers available for the accurate diagnosis of zinc-deficiency in individuals. Additionally, a comprehensive view of the adverse effects of zinc deficiency is lacking. Our aim was to identify superior biomarkers of zinc deficiency and uncover the adverse effects of zinc deficiency.

METHODS

We performed multi-omics analysis using serum proteomics-metabolomics and liver proteomics on zinc-deficient rats to identify candidate biomarkers and reveal the associated adverse effects of zinc deficiency. Secondly, the candidate biomarkers were validated in two zinc-deficient populations and an RCT zinc supplementation trial on a zinc-deficient population.

RESULTS

Our integrated multi-omics approach revealed numerous biomarkers (>2000) and glutathione metabolism as the most important changed pathway in zinc deficiency. Three candidate biomarkers from glutathione metabolism were validated in repeated zinc-deficient rats by quantitative analysis. Only glutathione sulfotransferase omega-1 (GSTO1) (among 3 candidate biomarkers) was validated in the two zinc-deficient populations and zinc-supplemented population. Compared with serum zinc, serum GSTO1 yielded a better response to zinc supplementation and a higher correlation coefficient with zinc intake and the AUC value and has the potential for diagnosing zinc deficiency. By integrated multi-omics, we identified both established and novel adverse effects of zinc deficiency.

CONCLUSIONS

Our integrated multi-omics analysis revealed more complete information about zinc deficiency; GSTO1 was found to be a reliable potential biomarker for diagnosis of zinc deficiency. This trial is registered at http://www.chictr.org.cn/registry.aspx as ChiCTR1900028162.

Nutrient Intake Adequacy from Food and Beverage Intake of US Children Aged 1-6 Years from NHANES 2001-2016

The early years, between the ages of one and six, are a period of rapid physical, social and cognitive growth and a nutritionally adequate diet is an important factor for optimum development. We investigated the micronutrient adequacy and status of young US children aged 1–6 years (n = 9848) using 24-h dietary recall interviews completed by parents and caregivers participating in the National Health and Nutrition Examination Survey (NHANES) 2001–2016. data. The proportion of the sample not meeting the Dietary Reference Intakes (DRI) increased with increasing age and was most pronounced for calcium. Despite adequate iron intake, 7.4% and 2.5% had signs of iron deficiency and anemia based on serum ferritin and hemoglobin levels, with younger children and WIC participants at most risk and Non-Hispanic Black children the least. Vitamin B6 intake was adequate, but 6.4% had serum pyridoxal-5-phosphate deficiency. For vitamin E, 69% had intakes below the estimated average requirement (EAR), yet serum deficiency was only detected in 0.9%. Vitamin D intake was inadequate for 87%, but true deficiency may be overestimated. Mean DHA intake was 24 mg/d, well below expert recommendations of 70–100 mg/day. Iron and vitamin B6 deficiency and inadequate calcium, fiber, choline, potassium and DHA intakes are a concern for a significant percentage of young children. The discrepancy between nutrient intakes and serum deficiency levels needs to be further investigated.

Calcium prescription by Indian orthopaedic surgeons: A survey and a review of literature

BACKGROUND

Orthopaedic surgeons prefer calcium supplement for various pathologies like fracture, osteoporosis, chronic musculoskeletal pain, yet there is no proper evidence to support the benefits of taking them regularly. The average requirement for calcium is around 500-1000 mg/day for a healthy adult, this amount of calcium is not achieved by diet, especially in developing countries like India. Despite this, the serum calcium level remains unaltered, due to the well-controlled absorption and excretion of calcium by the human body. As there is no clarity over the dose, duration and the prefered calcium salts, we constructed a survey to find the preferred dose, duration, the preferred calcium salts among orthopaedic surgeons, and to give an in-depth review of literature about dose, duration, timing, preferred calcium salt and various other calcium-related queries.

MATERIALS AND METHOD

The survey included 15 pre-structured questionnaires; these questions were formatted and validated by senior surgeons and other specialists after a through a review of calcium-related literature. These questionnaires were used in a pilot study conducted within the department and were later modified and separated into 7 sections. Data were collected by both online survey (google forms) and direct interviews.

RESULT AND CONCLUSION

128 Orthopedic surgeons responded. The total number of response obtained was 2355. Unanswered questions were 152. From the survey, it was found that most orthopaedic surgeons prefer to prescribe calcium routinely (55.46%). The commonly used calcium salt was calcium carbonate (47.65%), followed by citrate (32.8%). 42.18% were not aware of the efficiency of prescribing calcium in divided doses. Most responded that calcium is not to be given for patients with renal stones, but literature shows that calcium prescribed reduces the recurrence of commonest kidney stones, calcium oxalate stones.

Fecal g. Streptococcus and g. Eubacterium_coprostanoligenes_group combined with sphingosine to modulate the serum dyslipidemia in high-fat diet mice

BACKGROUND & AIMS

Although high-fat diet (HFD) could impact the composition of fecal microbiome and their metabolites, it is still largely unknown which fecal bacteria and metabolites are relatively important in responding to the HFD. This study aimed to identify the crucial fecal bacteria and metabolites in the HFD mice using a microbial-metabolite network, and to investigate the synergistic mediation effect of the crucial fecal bacteria and metabolites on serum dyslipidemia induced by the HFD.

METHODS

The 16srDNA sequencing and the ultra-performance liquid chromatography (UPLC/TOF MSMS) platform were performed to characterize the composition and function of fecal microbiome, and metabolites in the HFD. The microbial-metabolite network, correlation and mediation analyses were performed to examine the relationships among fecal microbiome, metabolites, and serum dyslipidemia indicators. Mice models were conducted to evaluate the effect of fecal metabolite on dyslipidemia.

RESULTS

Compared to the control, 32 genera were altered in the HFD, including 26 up-regulated and 6 down-regulated. A total of 42 altered pathways were observed between the control and HFD, and the "Glycosphingolipid biosynthesis" was identified as the most significant pathway (fold change = 0.64; p < 0.001). Meanwhile, 49 fecal metabolites were altered in the HFD, and the fecal microbiome was associated with the fecal metabolism (M2 = 0.776, p = 0.008). Based on the microbial-metabolite network, two major hub genera were screened (HUB1: g. Streptococcus, HUB2: g. Eubacterium_coprostanoligenes_group), and one bacterial metabolite, sphingosine, was found in this study. Further, the HUB2 was positively associated with fecal sphingosine (r = 0.646, p = 0.001), and its downstream metabolic pathway, "Glycosphingolipid biosynthesis" pathway (r = 0.544, p = 0.009). The regulatory relationship between the HUB2 and sphingosine synergistically mediated the effect of HFD on TCHO (33.7%), HDL-C (37.3%), and bodyweight (36.7%). Besides, compared to the HFD, the HFD with sphingosine supplementation had lower bodyweight (35.12 ± 1.23 vs. 39.42 ± 1.25, p < 0.001), TG (0.44 ± 0.08 vs. 0.52 ± 0.05, p = 0.002), TCHO (3.81 ± 0.34 vs. 4.51 ± 0.38, p = 0.002), and LDL-c (0.82 ± 0.09 vs. 0.97 ± 0.15, p = 0.016).

CONCLUSIONS

The g. Streptococcus and g. Eubacterium_coprostanoligenes are two hub genera in the fecal micro-ecosystem of the HFD, and the g. Eubacterium_coprostanoligenes mediates the effect of HFD on dyslipidemia through sphingosine. Sphingosine supplementation can improve dyslipidemia induced by HFD.

Serum biomarkers of the calcium-deficient rats identified by metabolomics based on UPLC/Q-TOF MS/MS

BACKGROUND

We previously identified the urinary biomarkers to diagnose calcium deficiency and nutritional rickets by ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS/MS). To find biomarkers of calcium deficiency and further confirm these biomarkers in serum, we performed serum metabolomics analysis of calcium-deficient rats.

METHODS

A calcium-deficient rat model was established with a low-calcium diet for 12 weeks. Serum metabolomics based UPLC/Q-TOF MS/MS and multivariate statistical analysis was performed to identify the alterations in metabolites associated with calcium deficiency in rats.

RESULTS

Bone mineral density, serum parathyroid hormone and alkaline phosphatase were significantly decreased in the low-calcium diet group (LCG) compared to the normal calcium diet group (NCG). Serum metabolic-profiling analysis could definitively distinguish between the LCG and NCG and identified 24 calcium-deficient biomarkers. Three metabolites (indoxyl sulfate, phosphate, and taurine) of the 24 biomarkers were found in our previous urinary metabolomics study of rats with a calcium deficiency and nutritional rickets. The areas under the curve (AUCs) of these three biomarkers were greater than 0.8, and the combination of any two biomarkers was higher than 0.95.

CONCLUSION

Dietary calcium deficiency induced the alterations of metabolites in the serum of rats, and the three identified biomarkers had relatively high diagnostic values for calcium deficiency in rats.

Urinary Metabolic Profiling via LC-MS/MS Reveals Impact of Bovine Lactoferrin on Bone Formation in Growing SD Rats

Lactoferrin (LF) exerts a promoting bone health function. The effects of LF on bone formation at the metabolic level have been less explored. Urinary metabolic profiling of growing Sprague-Dawley (SD) rats LF-supplemented (1000 mg/kg bw) for four weeks were explored by Liquid chromatography–tandem mass spectrometry (LC-MS/MS). The serum markers of bone formation and bone resorption, the bone mass, and the osteogenesis markers of femur were measured by an enzyme-linked immunosorbent assay, micro-computerized tomography, and immunohistochemistry, respectively. Compared with the control, LF supplementation improved bone formation (p < 0.05), reduced bone resorption (p < 0.05), enhanced femoral bone mineral density and microarchitecture (p < 0.05), and upregulated osteocalcin, osterix, and Runx-2 expression (p < 0.05) of femur. LF upregulated 69 urinary metabolites. KEGG and pathway enrichment analyses of those urinary metabolites, and the Person’s correlation analyses among those urinary metabolites and bone status revealed that LF impacted on bone formation via regulatory comprehensive pathways including taurine and hypotaurine metabolism, arginine and proline metabolism, cyanoamino acid metabolism, nitrogen metabolism, nicotinate and nicotinamide metabolism, and fatty acid biosynthesis. The present study indicated the metabolomics is a useful and practical tool to elucidate the mechanisms by which LF augments bone mass formation in growing animals.

Effects of Long-Term Calcium Supplementation on Rats Bone Mineral Density and Cardiovascular Based on Metabonomics

Calcium supplements were necessary for those people with low calcium intake and high risk of osteoporosis. Recent cohort studies have shown that long-term calcium supplements may raise the risk of cardiovascular disease, but its mechanism is still unclear. In this study, metabonomics were employed to evaluate the changes of metabolism in rats with long-term calcium supplementation and further seek the potential markers of cardiovascular risk. SD rats were divided into two groups including normal control group (calcium intake, 0.50 g/kg bw) and high calcium supplement group (calcium intake, 2.50 g/kg bw). After 6 mo, the cardiovascular system and bone mineral density were observed. UPLC-MS was used to analyze serum metabonomics in rats. The results showed that the contents of total cholesterol and low-density lipoprotein cholesterol in the high calcium group were significantly higher than those in normal control group (p<0.05). The interventricular septum thickness (IVS), left ventricular mass (LVM), left ventricular posterior wall thickness (LVPW) in the high calcium group were higher than those in normal control group (p<0.05). Serum metabonomics analysis showed that there were persistent changes in many metabolites such as sphingosine and its derivatives (p<0.01) in the comparison between the high calcium group and the normal group. These results indicated that long term calcium supplementation can lead to dyslipidemia in rats, such as the rise of cholesterol and low-density lipoprotein, which might induce myocardial hypertrophy. Long-term calcium supplementation can cause the changes of the amount of sphingosine and its derivatives in the body, which many have potential risk to cardiovascular diseases such as myocardial hypertrophy and atherosclerosis.

S, Hegde A, ES SP, Johnson RP, Das SP, Vazirally S, Rekha PD. Effect of calcium glucoheptonate on proliferation and osteogenesis of osteoblast-like cells in vitro

Calcium is the key macromineral having a role in skeletal structure and function, muscle contraction, and neurotransmission. Bone remodeling is maintained through a constant balance between calcium resorption and deposition. Calcium deficiency is resolved through calcium supplementation, and among the supplements, water-soluble organic molecules attracted great pharmaceutical interest. Calcium glucoheptonate is a highly water-soluble organic calcium salt having clinical use; however, detailed investigations on its biological effects are limited. We assessed the effects of calcium glucoheptonate on cell viability and proliferation of osteoblast-like MG-63 cells. Calcium uptake and mineralization were evaluated using Alizarin red staining of osteoblast-like MG-63 cells treated with calcium glucoheptonate. Expression of osteogenic markers were monitored by western blotting, immunofluorescence, and qRT-PCR assays. Increased proliferation and calcium uptake were observed in the MG-63 cells treated with calcium glucoheptonate. The treatment also increased the expression of osteopontin and osteogenic genes such as collagen-1, secreted protein acidic and cysteine rich (SPARC), and osteocalcin. Calcium glucoheptonate treatment did not exert any cytotoxicity on colorectal and renal epithelial cells, indicating the safety of the treatment. This is the first report with evidence for its beneficial effect for pharmaceutical use in addressing calcium deficiency conditions.

Metabolomic profiling to identify effects of dietary calcium reveal the influence of the individual and postprandial dynamics on the canine plasma metabolome

Short-term feeding studies have highlighted a phenomenon in Ca regulation that raises concerns around Ca absorption in dogs that may make an impact on commercial diets near to the maximum recommended level. A recent study to determine responses in dogs fed one of two diets differing in dietary Ca over 40 weeks found no evidence to suggest a concern across a range of biological parameters hypothesised to be affected by Ca. Unforeseen consequences of dietary Ca could have occurred and metabolic profiling was deemed a suitable data-driven approach to identify effects of dietary Ca. The objectives were to compare the fasted plasma metabolome (sampled at 8-week intervals over 40 weeks) of dogs fed one of two diets, near to the minimum and maximum recommended levels of dietary Ca. Comparisons with the control diet were also investigated across the postprandial time course (1-4 h) following acute (1 d) and long-term (24 weeks) feeding of the test diet. Comparing fasted plasma samples at each time point, no significant effect (adjusted P < 0·05) of diet on metabolites was observed. In the postprandial state, only phosphate was consistently different between diets and was explained by additional dietary P to maintain Ca:P. Metabolic profiling analysis supports the view that the dietary Ca upper limit is safe. Additionally, the canine plasma metabolome was characterised, providing insights into the stability of individual profiles across 40 weeks, the response to consumption of a nutritionally complete meal over a 4 h postprandial time course and different kinetic categories of postprandial absorption.

Harnessing Finger Millet to Combat Calcium Deficiency in Humans: Challenges and Prospects

Humans require more than 20 mineral elements for healthy body function. Calcium (Ca), one of the essential macromineral, is required in relatively large quantities in the diet for maintaining a sound overall health. Young children, pregnant and nursing women in marginalized and poorest regions of the world, are at highest risk of Ca malnutrition. Elderly population is another group of people most commonly affected by Ca deficiency mainly in the form of osteoporosis and osteopenia. Improved dietary intake of Ca may be the most cost-effective way to meet such deficiencies. Finger millet [Eleusine coracana (L.) Gaertn.], a crop with inherently higher Ca content in its grain, is an excellent candidate for understanding genetic mechanisms associated with Ca accumulation in grain crops. Such knowledge will also contribute toward increasing Ca contents in other staple crops consumed on daily basis using plant-breeding (also known as biofortification) methods. However, developing Ca-biofortified finger millet to reach nutritional acceptability faces various challenges. These include identifying and translating the high grain Ca content to an adequately bioavailable form so as to have a positive impact on Ca malnutrition. In this review, we assess some recent advancements and challenges for enrichment of its Ca value and present possible inter-disciplinary prospects for advancing the actual impact of Ca-biofortified finger millet.

A 1H-NMR based metabolomics study of the intervention effect of mangiferin on hyperlipidemia hamsters induced by a high-fat diet

It has been demonstrated that mangiferin can ameliorate hypertriglyceridemia by modulating the expression levels of genes involved in lipid metabolism in animal experiments, but its effects on the serum metabolic fingerprinting of hyperlipidemia animal models have not been reported. Thus, a NMR-based metabolomics approach was conducted to explore the effects of mangiferin on hyperlipidemia hamsters and to gain a better understanding of the involved metabolic pathways. Hamsters fed with a high-fat diet were orally administered with mangiferin 150 mg per kg BW once a day for 8 weeks. Serum samples were analysed by 1H NMR, and multivariate statistical analysis was applied to the data to identify potential biomarkers. In total, 20 discriminating metabolites were identified. It turned out that mangiferin administration can partly reverse the metabolism disorders induced by a high-fat diet and exerted a good anti-hypertriglyceridemia effect. Mangiferin ameliorated hyperlipidemia by intervening in some major metabolic pathways, involving glycolysis, the TCA cycle, synthesis of ketone bodies, and BCAAs as well as choline and lipid metabolism. These findings provided new essential information on the effects of mangiferin and demonstrated the great potential of this nutrimetabolomics approach.

1H NMR-based metabolomics study on repeat dose toxicity of fine particulate matter in rats after intratracheal instillation

Systemic metabolic effects and toxicity mechanisms of ambient fine particulate matter (PM_2.5) remain uncertain. In order to investigate the mechanisms in PM_2.5 toxicity, we explored the endogenous metabolic changes and possible influenced metabolic pathways in rats after intratracheal instillation of PM_2.5 by using a ¹H nuclear magnetic resonance (NMR)-based metabolomics approach. Liver and kidney histopathology examinations were also performed. Chemical characterization demonstrated that PM_2.5 was a complex mixture of elements. Histopathology showed cellular edema in liver and glomerulus atrophy of the PM_2.5 treated rats. We systematically analyzed the metabolites changes of serum and urine in rats using ¹H NMR techniques in combination with multivariate statistical analysis. Significantly reduced levels of lactate, alanine, dimethylglycine, creatine, glycine and histidine in serum, together with increased levels of citrate, arginine, hippurate, allantoin and decreased levels of allthreonine, lactate, alanine, acetate, succinate, trimethylamine, formate in urine were observed of PM_2.5 treated rats. The mainly affected metabolic pathways by PM_2.5 were glycine, serine and threonine metabolism, glyoxylate and dicarboxylate metabolism, citrate cycle (TCA cycle), nitrogen metabolism and methane metabolism. Our study provided important information on assessing the toxicity of PM_2.5 and demonstrated that metabolomics approach can be employed as a tool to understand the toxicity mechanism of complicated environmental pollutants.

Effects of Histidine Supplementation on Global Serum and Urine 1H NMR-based Metabolomics and Serum Amino Acid Profiles in Obese Women from a Randomized Controlled Study

The aim of current study was to investigate the metabolic changes associated with histidine supplementation in serum and urine metabolic signatures and serum amino acid (AA) profiles. Serum and urine 1H NMR-based metabolomics and serum AA profiles were employed in 32 and 37 obese women with metabolic syndrome (MetS) intervened with placebo or histidine for 12 weeks. Multivariable statistical analysis were conducted to define characteristic metabolites. In serum 1H NMR metabolic profiles, increases in histidine, glutamine, aspartate, glycine, choline, and trimethylamine-N-oxide (TMAO) were observed; meanwhile, decreases in cholesterol, triglycerides, fatty acids and unsaturated lipids, acetone, and α/β-glucose were exhibited after histidine supplement. In urine 1H NMR metabolic profiles, citrate, creatinine/creatine, methylguanidine, and betaine + TMAO were higher, while hippurate was lower in histidine supplement group. In serum AA profiles, 10 AAs changed after histidine supplementation, including increased histidine, glycine, alanine, lysine, asparagine, and tyrosine and decreased leucine, isoleucine, ornithine, and citrulline. The study showed a systemic metabolic response in serum and urine metabolomics and AA profiles to histidine supplementation, showing significantly changed metabolism in AAs, lipid, and glucose in obese women with MetS.

The Dynamic Microbiota Profile During Pepper (Piper nigrum L.) Peeling by Solid-State Fermentation

White pepper (Piper nigrum L.), a well-known spice, is the main pepper processing product in Hainan province, China. The solid-state method of fermentation can peel pepper in a highly efficient manner and yield high-quality white pepper. In the present study, we used next-generation sequencing to reveal the dynamic changes in the microbiota during pepper peeling by solid-state fermentation. The results suggested that the inoculated Aspergillus niger was dominant throughout the fermentation stage, with its strains constituting more than 95% of the fungi present; thus, the fungal community structure was relatively stable. The bacterial community structure fluctuated across different fermentation periods; among the bacteria present, Pseudomonas, Tatumella, Pantoea, Acinetobacter, Lactococcus, and Enterobacter accounted for more than 95% of all bacteria. Based on the correlations among the microbial community, we found that Pseudomonas and Acinetobacter were significantly positively related with A. niger, which showed strong synergy with them. In view of the microbial functional gene analysis, we found that these three bacteria and fungi were closely related to the production of pectin esterase (COG4677) and acetyl xylan esterase (COG3458), the key enzymes for pepper peeling. The present research clarifies the solid-state fermentation method of pepper peeling and lays a theoretical foundation to promote the development of the pepper peeling process and the production of high-quality white pepper.

Metabonomic analysis of the protective effect of quercetin on the toxicity induced by mixture of organophosphate pesticides in rat urine

The present study aims to investigate the protective effect of quercetin against the joint toxic action induced by the mixture of four organophosphate pesticides (mixture-OPs) (dimethoate, acephate, dichlorvos, and phorate) at their corresponding no observed adverse effect level (NOAEL) using metabonomics. Rats were randomly divided into control, quercetin-treated, mixture-OPs-treated, and quercetin plus mixture-OPs-treated groups. Mixture-OPs and quercetin were given to the rats daily through drinking water and intragastric administration, respectively, for 90 days. The metabonomic profiles of rat urine were analyzed using ultra-performance liquid chromatography–mass spectrometry (UPLC/MS). The 14 metabolites significantly changed in the treatment groups compared with the control group, including the biomarkers of OPs exposure (dimethylphosphate, dimethyldithiophosphate, diethylphosphate) and the metabolites of quercetin (quercetin and isorhamnetina). The intensities of gentisic acid, creatinine, suberic acid, hippuric acid, uric acid, and citric acid significantly decreased, whereas the intensities of 7-methylguanine, estrone sulfate, and cholic acid significantly increased, in the mixture-OPs-treated group compared with the control group ( p < 0.01). The variation tendency of the aforementioned metabolites was significantly ameliorated in the high-dose quercetin (50 mg/(kg bw day)) plus mixture-OPs-treated group compared with the mixture-OPs-treated group ( p < 0.05). However, the intensities of these metabolites in the high-dose quercetin plus mixture-OPs-treated group were still significantly different from those of the control group ( p < 0.05). Results indicated that high dose of quercetin elicits a partial protective effect on the toxicity induced by mixture-OPs, including fatty acid and energy metabolism, antioxidant defense system, DNA damage, and liver and kidney function.

A urinary metabonomics analysis of long-term effect of acetochlor exposure on rats by ultra-performance liquid chromatography/mass spectrometry

The study was to assess the long-term toxic effects of acetochlor on rats. Two different doses (42.96 and 107.4 mg/kg body weight/day) of acetochlor were administered to Wistar rats through their food for over 24 weeks. Rat urine samples were collected at two time-points for the measurements of the metabonomics profiles with ultra-performance liquid chromatography-mass spectrometry (UPLC-MSMS). The results of clinical chemistry and histopathology suggested that long-term use of acetochlor in rats caused liver and kidney damage, and dysfunction of antioxidant system. The urinary metabonomics analysis indicated that the high and low-dose exposure of acetochlor could cause alterations of these metabonomics in urine in the rat. Significant changes of the levels of hippuric acid (0.403-fold decrease), citric acid (0.430-fold decrease), pantothenic acid (0.486-fold decrease), uracil (0.419-fold decrease), β-Alanine (0.325-fold decrease), nonanedioic acid (0.445-fold decrease), L-tyrosine (0.410-fold decrease), D-glucuronic acid (8.389-fold increase) and 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide in urine were observed. In addition, it may interfere with the fatty acid synthesis, the pyrimidine degradation and pantothenate biosynthesis. The level of 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide is detected in all treated groups which is not found in the control groups, indicating which can be used as an early, sensitive marker of acetochlor exposure in rat. This study illustrates the important utility of metabonomics approaches to understand the toxicity of long-term exposure of acetochlor.

Potential serum biomarkers from a metabolomics study of autism

BACKGROUND

Early detection and diagnosis are very important for autism. Current diagnosis of autism relies mainly on some observational questionnaires and interview tools that may involve a great variability. We performed a metabolomics analysis of serum to identify potential biomarkers for the early diagnosis and clinical evaluation of autism.

METHODS

We analyzed a discovery cohort of patients with autism and participants without autism in the Chinese Han population using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS/MS) to detect metabolic changes in serum associated with autism. The potential metabolite candidates for biomarkers were individually validated in an additional independent cohort of cases and controls. We built a multiple logistic regression model to evaluate the validated biomarkers.

RESULTS

We included 73 patients and 63 controls in the discovery cohort and 100 cases and 100 controls in the validation cohort. Metabolomic analysis of serum in the discovery stage identified 17 metabolites, 11 of which were validated in an independent cohort. A multiple logistic regression model built on the 11 validated metabolites fit well in both cohorts. The model consistently showed that autism was associated with 2 particular metabolites: sphingosine 1-phosphate and docosahexaenoic acid.

LIMITATIONS

While autism is diagnosed predominantly in boys, we were unable to perform the analysis by sex owing to difficulty recruiting enough female patients. Other limitations include the need to perform test-retest assessment within the same individual and the relatively small sample size.

CONCLUSION

Two metabolites have potential as biomarkers for the clinical diagnosis and evaluation of autism.

The Harbin Cohort Study on Diet, Nutrition and Chronic Non-communicable Diseases: study design and baseline characteristics

Diet and nutrition have been reported to be associated with many common chronic diseases and blood-based assessment would be vital to investigate the association and mechanism, however, blood-based prospective studies are limited. The Harbin Cohort Study on Diet, Nutrition and Chronic Non-communicable Diseases was set up in 2010. From 2010 to 2012, 9,734 participants completed the baseline survey, including demographic characteristics, dietary intake, lifestyles and physical condition, and anthropometrics. A re-survey on 490 randomly selected participants was done by using the same methods which were employed in the baseline survey. For all participants, the mean age was 50 years and 36% of them were men. Approximately 99.4 % of cohort members donated blood samples. The mean total energy intake was 2671.7 kcal/day in men and 2245.9 kcal/day in women, the mean body mass index was 25.7 kg/m² in men and 24.6 kg/m² in women, with 18.4% being obese (≥28 kg/m²), 12.7% being diabetic, and 29.5% being hypertensive. A good agreement was obtained for the physical measurements between the baseline survey and re-survey. The resources from the cohort and its fasting and postprandial blood samples collected both at baseline and in each follow-up will be valuable and powerful in investigating relationship between diet, nutrition and chronic diseases and discovering novel blood biomarkers and the metabolism of these biomarkers related to chronic diseases.

Vitamin D-enhanced duodenal calcium transport

For humans and rodents, duodenum is a very important site of calcium absorption since it is exposed to ionized calcium released from dietary complexes by gastric acid. Calcium traverses the duodenal epithelium via both transcellular and paracellular pathways in a vitamin D-dependent manner. After binding to the nuclear vitamin D receptor, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] upregulates the expression of several calcium transporter genes, e.g., TRPV5/6, calbindin-D9k, plasma membrane Ca(2+)-ATPase1b, and NCX1, thereby enhancing the transcellular calcium transport. This action has been reported to be under the regulation of parathyroid-kidney-intestinal and bone-kidney-intestinal axes, in which the plasma calcium and fibroblast growth factor-23 act as negative feedback regulators, respectively. 1,25(OH)2D3 also modulates the expression of tight junction-related genes and convective water flow, presumably to increase the paracellular calcium permeability and solvent drag-induced calcium transport. However, vitamin D-independent calcium absorption does exist and plays an important role in calcium homeostasis under certain conditions, particularly in neonatal period, pregnancy, and lactation as well as in naturally vitamin D-impoverished subterranean mammals.

PubChem applications in drug discovery: a bibliometric analysis

A bibliometric analysis of PubChem applications is presented by reviewing 1132 research articles. The massive volume of chemical structure and bioactivity data in PubChem and its online services have been used globally in various fields including chemical biology, medicinal chemistry and informatics research. PubChem supports drug discovery in many aspects such as lead identification and optimization, compound-target profiling, polypharmacology studies and unknown chemical identity elucidation. PubChem has also become a valuable resource for developing secondary databases, informatics tools and web services. The growing PubChem resource with its public availability offers support and great opportunities for the interrogation of pharmacological mechanisms and the genetic basis of diseases, which are vital for drug innovation and repurposing.

Biomarkers identified by urinary metabonomics for noninvasive diagnosis of nutritional rickets

Nutritional rickets is a worldwide public health problem; however, the current diagnostic methods retain shortcomings for accurate diagnosis of nutritional rickets. To identify urinary biomarkers associated with nutritional rickets and establish a noninvasive diagnosis method, urinary metabonomics analysis by ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry and multivariate statistical analysis were employed to investigate the metabolic alterations associated with nutritional rickets in 200 children with or without nutritional rickets. The pathophysiological changes and pathogenesis of nutritional rickets were illustrated by the identified biomarkers. By urinary metabolic profiling, 31 biomarkers of nutritional rickets were identified and five candidate biomarkers for clinical diagnosis were screened and identified by quantitative analysis and receiver operating curve analysis. Urinary levels of five candidate biomarkers were measured using mass spectrometry or commercial kits. In the validation step, the combination of phosphate and sebacic acid was able to give a noninvasive and accurate diagnostic with high sensitivity (94.0%) and specificity (71.2%). Furthermore, on the basis of the pathway analysis of biomarkers, our urinary metabonomics analysis gives new insight into the pathogenesis and pathophysiology of nutritional rickets.