High Levels Of Leucine Research Articles

Different dietary branched-chain amino acid ratios, crude protein levels, and protein sources can affect the growth performance and meat yield in broilers

Balanced ratios of branched-chain amino acids (BCAAs) can enhance chicken growth, immunity, and muscle synthesis. However, these ratios can be affected by changes in crude protein (CP) levels or the substitution of protein sources, leading to BCAA antagonism. This, in turn, can have a negative impact on chicken growth. In Experiment 1, a total of 960 0-d-old male Cobb 500 broilers were divided into 6 treatments with 8 replicates. Three different BCAA ratios were used in High or Low CP diets as follows: 1) Low Leu group (Low level of leucine with increased valine and isoleucine levels), 2) Med Leu group, and 3) High Leu group (High level of leucine with reduced valine and isoleucine levels) for a total of 6 diets. In Experiment 2, a total of 640 0-d-old male Cobb 500 broilers were divided into 4 treatments with 8 replicates. The four diets had either High or Low CP and one of two protein sources with the same medium levels of BCAAs: 1) the soybean meal (SBM) group, which had SBM as the main protein source (protein bound AA), and 2) the wheat middlings with non-bound AAs (WM+AA) group (non-bound AA), which had additional non-bound AAs to replace SBM. The High Leu diet had a negative effect on overall growth performance, carcass weight, breast muscle weight, and body mineral composition compared to the Low Leu and Med Leu groups, particularly in the High CP diet (P < 0.05). The SBM group showed increased growth performance, breast muscle weight, expression levels of genes promoting muscle growth, and improved bone mineral composition compared to the WM+AA group, and the High CP group intensified the negative effect of the WM+AA diet (P < 0.05). In summary, balanced BCAA ratios and SBM-based diets have positive effects on chicken growth and muscle accretion, whereas excessive leucine and non-bound AA levels in the diets may negatively affect growth performance and meat yield in chickens.

The biochemical composition of wild berries and fruits growing in the Southwestern Taimyr

This article presents research findings on the chemical composition of fruits and berries found in the Southwestern Taimyr region, including bilberry (Vaccinium myrtíllus), northern redcurrant (Ribes triste), blueberry (Vaccinium uliginosum), prickly wild rose (Rosa acicularis), lingonberry (Vaccinium vitis-idaea), almost-holarctic crowberry (Empetrum subholarcticum), Siberian rowan (Sorbus sibirica), and cloudberry (Rubus chamaemorus). We revealed that rowan, blueberries, and prickly wild rose are particularly rich in crude fat. Additionally, prickly wild rose, and red currants were found to be high in crude fiber content, while bilberries, red currants, and cloudberries were dominant in crude protein. Potassium and calcium content were highest in prickly wild rose and rowan, while bilberries, red currants, and prickly wild rose had high sodium content. Moreover, crowberries and rowan berries were rich in phosphorus, and lingonberries, rowan berries, bilberries, and cloudberries were abundant in magnesium. Red currants, bilberries, and cloudberries had the highest total amino acid content, with essential amino acids being more prevalent than non-essential ones in redcurrant, bilberry, crowberry, and cloudberry samples. The content included high levels of leucine, isoleucine, valine, and threonine. Overall, the fruits and berries in the Southwestern Taimyr region have significant biological value and could be effectively used in creating functional biologically active substances.

Quality of edible bird’s nest treated by keratinolytic enzymes-based cleaning solution

Edible bird's nest (EBN) is one of the luxury foods that is widely used as a healthy food due to its nutritional value and therapeutic benefits. The traditional EBN washing process causes a reduction in weight and nutrient content and an increase in pollutants due to the use of hydrogen peroxide. An exploratory observation method was used to examine the quality of EBN from Collocalia fuciphaga before and after washing using a washing solution based on keratinolytic enzymes. There are four stages of EBN cleaning i.e. cleaning by tap water, ethanol solution, enzyme solution at room temperature and 50oC and drying at 40oC for 42 hrs. A total of 60 EBN (unclean, n = 30) and clean, n = 30) were analyzed using the AOAC method. The mineral content of Ca, Fe, K and Mg using atomic absorption spectrophotometry (AAS) except that P was measured by spectrophotometer. A carbohydrate estimation kit was used to measure glycoprotein content and the amino acid content was determined using the HPLC method. Evaluation of the cleanliness was carried out using a scoring system by semi-trained panelists. The results obtained showed that the clean EBNs were slightly yellowish-white in color, and the cleanliness of EBN before and after cleaning increased from 2.35 to 3.84. Clean EBN protein content decreased by 7.2% while total amino acids decreased from 38.51% to 32.71%. Clean EBN contains eight essential amino acids of 17.93% with high levels of leucine, valine, arginine, and threonine (2.42-2.96%). EBN's clean ash content increased from 3.7% to 7.8%. Carbohydrate content and iron in clean EBN were 39.19±0.76% and 14.35 mg/100 g dry matter, respectively. The high levels of carbohydrates and iron appear to be good sources of glycoprotein to support health and have the potential as an alternative source of iron for people with anemia. The stepwise EBN washing method using tapwater, ethanol and a washing solution based on keratinolytic enzymes can be applied to reduce weight loss and improve the quality of EBN.

Aumento acentuado da leucina como fator de mau prognóstico na doença da urina de xarope de bordo - relato de caso

INTRODUCTION: Leucinosis or Maple Syrup Disease (MSD) is an innate metabolism error caused by a deficiency in the activity of the alpha-keto acid-dehydrogenase enzyme complex, which leads to the accumulation of essential branched-chain amino acids (leucine, valine, and isoleucine), leucine is particularly toxic to the central nervous system (CNS). OBJECTIVES: Report a case of maple syrup disease in a 10-day-old newborn (NB), born to consanguineous parents, with late diagnosis, with high levels of leucine, with an unfavorable prognosis. COMMENTS: MSD is a rare condition, of autosomal recessive origin, which occurs due to the accumulation of essential branched-chain amino acids in tissues(leucine, valine, and isoleucine). The accumulation of amino acids mainly affects the CNS. Studies have shown that the elevated leucine concentration decreases the serum sodium concentration and increases intracellular water, causing cerebral edema. Neurological damage will depend on the degree and time of tissue exposure to metabolites. Despite the unfavorable outcome of the case presented, the prognosis of MSD can be modified with strict diet control and early and aggressive management of metabolic crisis.

NLRP3 is a promising target for regulating high glucose-induced inflammatory response in Megalobrama amblycephala

The nucleotide-binding domain, leucine-rich repeat and pyrin domain containing protein 3 (NLRP3) has emerged as a key regulator of glucose homeostasis in mammals, while relevant information are still poorly interpreted in aquatic animals. Herein, we cloned and characterized NLRP3 gene from Megalobrama amblycephala, and analyzed its function in high glucose (HG)-induced inflammation. Full-length cDNA of NLRP3 measured 4380 bp with 3570 bp open reading frame encoding 1189 amino acids, compared with Pimephales promelas, it displayed 90.3% homology. Structural analysis revealed that M. amblycephala NLRP3 processed characteristic domains of pyrin, FISNA, NACHT, CARD and LRRs. Spatial expression analysis displayed NLRP3 was ubiquitously expressed in eight organs/tissues (gill, liver, spleen, intestine, head kidney, white muscle, heart and brain) with largest magnitude in head kidney. After a 13-week nutritional experiment, carbohydrate-enriched (45%) diets significantly upregulated NLRP3 mRNA levels in the liver and white muscle than that of the control (30%) diets. Glucose loading caused a significantly increased NLRP3 mRNA levels in the white muscle and liver, with maximum values got at 1 and 2 h, respectively. Subsequently, the mRNA levels rapidly returned to the basal level at 12 h. As for the in-vitro experiments, both ATP and high-glucose treatments remarkably increased the expression of NLRP3 and pro-inflammatory cytokines (IL1β and IL6) in hepatocytes. Additionally, high-leucine (30 mM) levels remarkably increased NLRP3 protein content and transcriptions of NLRP3, NF-κB, IL1β and IL6 than those of the HG and HG + low leucine (10 mM) treatment groups, while the opposite was true for IL8 and IL10. Overall, our findings indicated that M. amblycephala NLRP3 is highly conserved compared with other vertebrates. NLRP3 participated in the control of HG-induced inflammation, and high-leucine levels could aggravate HG-induced inflammation in hepatocytes of M. amblycephala via NLRP3 activation.

Exposure to leucine induces oxidative stress in the brain of zebrafish.

Maple Syrup Urine Disease (MSUD) is an autosomal recessive inherited disorder caused by a deficiency in the activity of the branched-chain alpha-ketoacid dehydrogenase complex leading to the accumulation of branched-chain amino acids (BCAA) leucine, isoleucine, and valine and their respective branched-chain α-ketoacids and corresponding hydroxy acids. Considering that Danio rerio, known as zebrafish, has been widely used as an experimental model in several research areas because it has favorable characteristics that complement other experimental models, this study aimed to evaluate oxidative stress parameters in zebrafish exposed to high levels of leucine (2mM and 5mM), in a model similar of MSUD. Twenty-four hours after exposure, the animals were euthanized, and the brain content dissected for analysis of oxidative stress parameters: thiobarbituric acid reactive substances (TBARS), 2',7'-dichlorofluorescein oxidation assay (DCF); content of sulfhydryl, and superoxide dismutase (SOD) and catalase (CAT) activities. Animals exposed to 2mM and 5mM leucine showed an increase in the measurement of TBARS and decreased sulfhydryl content. There were no significant changes in DCF oxidation. In addition, animals exposed to 2mM and 5mM leucine were found to have decreased SOD activity and increased CAT activity. Based on these results, exposure of zebrafish to high doses of leucine can act as a promising animal model for MSUD, providing a better understanding of the toxicity profile of leucine exposure and its use in future investigations and strategies related to the pathophysiology of MSUD.

Branched-Chain Amino Acids and Their Interactions With Lipid Metabolites for Increased Risk of Gestational Diabetes.

We aimed to explore associations of branched-chain amino acids (BCAA) in early pregnancy with gestational diabetes mellitus (GDM), and whether high BCAAs and lipidomics markers had interactive effects on the risk of GDM. We conducted a 1:1 case-control study (n = 486) nested in a prospective cohort of pregnant women in Tianjin, China. Blood samples were collected at their first antenatal care visit (median 10 gestational weeks). Serum BCAAs, saturated fatty acids (SFA) and lysophosphatidylcholines (LPC) were measured by liquid chromatography-tandem mass spectrometry analysis. Conditional logistic regression was performed to examine associations of BCAAs with the risk of GDM. Interactions between high BCAAs and high SFA16:0 for GDM were examined using additive interaction measures. High serum valine, leucine, isoleucine, and total BCAAs were associated with markedly increased risk of GDM (OR of top vs bottom tertiles: 1.91 [95% CI, 1.22-3.01]; 1.87 [1.20-2.91]; 2.23 [1.41-3.52]; 1.93 [1.23-3.02], respectively). The presence of high SFA16:0 defined as ≥ 17.1 nmol/mL (ie, median) markedly increased the ORs of high leucine alone and high isoleucine alone up to 4.56 (2.37-8.75) and 4.41 (2.30-8.43) for the risk of GDM, with significant additive interaction. After adjustment for LPCs, the ORs were greatly elevated (6.33, 2.25-17.80 and 6.53, 2.39-17.86) and the additive interactions became more significant. BCAAs in early pregnancy were positively associated with the risk of GDM, and high levels of leucine and isoleucine enhanced the risk association of high SFA16:0 with GDM, independent of LPCs.

Expression of 3-Methylcrotonyl-CoA Carboxylase in Brain Tumors and Capability to Catabolize Leucine by Human Neural Cancer Cells.

Simple SummaryLeucine is a ketogenic amino acid that is essential for sustaining cellular metabolism. To understand the leucine catabolizing capability of brain cancer cells, in this study, we evaluated the leucine removing ability of human glioma, glioblastoma, and neuroblastoma cells from their culture media. In addition, we also studied the generation of 2-oxoisocaproate, ketone bodies, and citrate. Further, we applied immunoprobing methods to evaluate the expression of 3-methylcrotonyl-CoA carboxylase (MCC) in cultured cells, and also in the human glioblastoma, astrocytoma, oligodendroglioma, and meningioma forming cells. Our results show that human cancer cells, in culture or in situ, express MCC and catabolize leucine. These results indicate that brain cancer cells could employ leucine catabolites as a substrate for their metabolism.Leucine is an essential, ketogenic amino acid with proteinogenic, metabolic, and signaling roles. It is readily imported from the bloodstream into the brain parenchyma. Therefore, it could serve as a putative substrate that is complementing glucose for sustaining the metabolic needs of brain tumor cells. Here, we investigated the ability of cultured human cancer cells to metabolize leucine. Indeed, cancer cells dispose of leucine from their environment and enrich their media with the metabolite 2-oxoisocaproate. The enrichment of the culture media with a high level of leucine stimulated the production of 3-hydroxybutyrate. When 13C6-leucine was offered, it led to an increased appearance of the heavier citrate isotope with a molar mass greater by two units in the culture media. The expression of 3-methylcrotonyl-CoA carboxylase (MCC), an enzyme characteristic for the irreversible part of the leucine catabolic pathway, was detected in cultured cancer cells and human tumor samples by immunoprobing methods. Our results demonstrate that these cancer cells can catabolize leucine and furnish its carbon atoms into the tricarboxylic acid (TCA) cycle. Furthermore, the release of 3-hydroxybutyrate and citrate by cancer cells suggests their capability to exchange these metabolites with their milieu and the capability to participate in their metabolism. This indicates that leucine could be an additional substrate for cancer cell metabolism in the brain parenchyma. In this way, leucine could potentially contribute to the synthesis of metabolites such as lipids, which require the withdrawal of citrate from the TCA cycle.

The Association Between Leucine and Diabetic Nephropathy in Different Gender: A Cross-Sectional Study in Chinese Patients With Type 2 Diabetes.

ObjectiveThis study aimed to evaluate how leucine are associated with diabetic nephropathy (DN) in type 2 diabetes (T2D) patients and the gender difference of this association.MethodsWe retrieved 1,031 consecutive patients with T2D who meet the inclusion and exclusion criteria from the same tertiary care center and extracted clinical information from electronic medical record. Plasma leucine was measured by liquid chromatography-mass spectrometer. Restricted cubic spline (RCS) was conducted to examine potential non-linear relationship between leucine and the risk of DN. Logistic regression was used to obtain odds ratio (OR) and confidence interval (CI). Additive interaction was used to estimate the interaction effect between leucine and gender for DN.ResultsWe found there was a negative correlation between leucine and the risk of DN. After stratifying all patients by gender, this relationship only remained significant in women (OR:0.57, CI:0.41–0.79).ConclusionsIn conclusion, T2D patients with high levels of leucine have a lower risk of developing DN in female.

Revisiting amino acid analyses for bioadhesives including a direct comparison of tick attachment cement (Dermacentor marginatus) and barnacle cement (Lepas anatifera)

With respect to potential applications in healthcare, pharmacy, the bonding industry, and cosmetics, biological adhesives produced from various animals are of high interest. A large number of species in the family Ixodidae produce an adhesive substance called attachment cement. This study focuses on the detailed investigation of the amino acid composition of the attachment cement from ticks (Dermacentor marginatus) and comparison with cement samples from barnacles (Lepas anatifera).Strong emphasis was laid on sample preparation of both types of cement and included the complete hydrolysis of proteins under either basic or acidic conditions. Stability of propyl chloroformate derivatives of the amino acids were measured by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) and gas chromatography electron ionisation tandem mass spectrometry (GC-EI-MS/MS) and were validated in terms of reproducibility and precision of analyses using NIST certified amino acid as well as protein standards. For the majority of the amino acids analytically valid recovery rates between 86 and 111% were achieved using GC-EI-MS/MS analysis after acidic hydrolysis.The method was applied for direct comparison of two biological glue systems, tick and barnacle cement. An outstandingly high content of glycine was present in the tick attachment cement; as were significant concentrations of leucine, serine and proline. In contrast, high levels of leucine, serine, aspartic acid/asparagine, glycine, glutamic acid/glutamine, alanine and valine were determined for barnacle cement. None of the samples showed the presence of 3,4-dihydroxy-phenylalanine (DOPA), yet tick attachment cement exhibited significantly higher concentration levels of tyrosine, the precursor of DOPA. It can clearly be stated that published results for amino acid analysis of barnacle cement show significantly under-/overestimation for some amino acids.Distinct differences in amino acid presence and concentration were observed for the two bio-adhesives. Although both have cement-like properties the data implied that different attachment mechanisms are involved for each of the organisms.

17 Challenges and implications of feeding diets with excess concentrations of leucine to growing-finishing pigs

Abstract Excess dietary leucine stimulates the key enzymes involved in branched-chain catabolism causing breakdown of all branched-chain amino acids, including isoleucine and valine. Branched-chain amino acids share a common brain transporter with other large neutral amino acids (LNAA). Excess levels of one of the LNAA increases brain uptake of that amino acid and decreases the uptake of the other LNAA, including tryptophan. Thus, excess leucine can impact the requirements for many amino acids. From a practical basis, this effect was first demonstrated with diets containing blood meal, but was thought to be of limited concern unless high blood meal diets were fed. Use of corn dried distillers grains with solubles (DDGS) or high protein DDGS in corn-based diets results in diets containing excess leucine. These high leucine levels are of limited concern if adequate levels of other branched-chain amino acids and LNAA are fed, which is often the case if the diet consists largely of intact protein sources. Feed grade amino acids, such as L-lysine, L-threonine, L-tryptophan, DL-methionine, L-valine, and L-isoleucine have been widely adopted as a means to lower nitrogen excretion and diet cost. Including these amino acids in diets containing corn products reduces dietary leucine; but the resulting diets are formulated near the requirement for the first 6 limiting amino acids, including valine, isoleucine, and tryptophan, while still being high in leucine. The excess leucine increases the requirements for valine, isoleucine, and possibly other LNAA, such as tryptophan and possibly others. The exact relationship between these amino acids and how to handle them in practical diet formulation is still being elucidated; however, recent meta-analysis and experimental data confirm the importance of these ratios and provide useful direction for future research.

High leucine levels affecting valine and isoleucine recommendations in low-protein diets for broiler chickens

Four experiments were conducted to estimate the optimal standardized ileal digestible (SID) level of branched-chain amino acids in low-protein diets during the starter, grower, and finisher periods, using the response surface methodology, and to study their effects on performance and mRNA expression of genes involved in the mechanistic target of rapamycin (mTOR) pathway of broiler chickens from 8 to 21 D of age. In experiments 1, 2, and 3, a total of 1,500 Cobb male broiler chickens were assigned to 15 diets of a central composite rotatable design (CCD) of response surface methodology containing 5 levels of SID Leu, Val, and Ile with 5 replicate pens of 20 birds each. A 3-factor, 5-level CCD platform was used to fit the second-order polynomial equation of broiler performance. In experiment 4, a total of 540 8-day-old Cobb male broiler chickens were distributed in a completely randomized 2 x 3 x 3 factorial arrangement with 2 SID Leu levels (1.28 or 1.83%), 3 SID Val levels (0.65, 0.90, or 1.20%), and 3 SID Ile levels (0.54, 0.79, or 1.09%) for a total of 18 treatments with 5 replicate cages of 6 birds each. High Leu levels impaired (P < 0.05) gain:feed when birds were fed marginal Val or Ile diets. However, gain:feed was restored when both Val and Ile were supplemented to reach adequate or high levels. High Leu levels increased (P < 0.05) mRNA expression of S6K1 and eEF2 genes only in birds fed high Ile levels. Dietary SID Leu, Val, and Ile levels required for gain:feed optimization in low-protein diets were estimated at 1.37, 0.94, and 0.87% during the starter period; 1.23, 0.82, and 0.75% during the grower period; and 1.15, 0.77, and 0.70% during the finisher phase, respectively. Higher Val and Ile levels are required to optimize the effect of Leu supplementation on mRNA expression of mTOR pathway genes in the pectoralis major muscle of broilers from day 1 to 21 after hatch.

Metabolic profiling of tissue-specific insulin resistance in human obesity: results from the Diogenes study and the Maastricht Study.

Recent evidence indicates that insulin resistance (IR) in obesity may develop independently in different organs, representing different etiologies toward type 2 diabetes and other cardiometabolic diseases. The aim of this study was to investigate whether IR in the liver and IR in skeletal muscle are associated with distinct metabolic profiles. This study includes baseline data from 634 adults with overweight or obesity (BMI ≥ 27 kg/m2) (≤65 years; 63% women) without diabetes of the European Diogenes Study. Hepatic insulin resistance index (HIRI) and muscle insulin sensitivity index (MISI), were derived from a five-point OGTT. At baseline 17 serum metabolites were identified and quantified by nuclear-magnetic-resonance spectroscopy. Linear mixed model analyses (adjusting for center, sex, body mass index (BMI), waist-to-hip ratio) were used to associate HIRI and MISI with these metabolites. In an independent sample of 540 participants without diabetes (BMI ≥ 27 kg/m2; 40-65 years; 46% women) of the Maastricht Study, an observational prospective population-based cohort study, 11 plasma metabolites and a seven-point OGTT were available for validation. Both HIRI and MISI were associated with higher levels of valine, isoleucine, oxo-isovaleric acid, alanine, lactate, and triglycerides, and lower levels of glycine (all p < 0.05). HIRI was also associated with higher levels of leucine, hydroxyisobutyrate, tyrosine, proline, creatine, and n-acetyl and lower levels of acetoacetate and 3-OH-butyrate (all p < 0.05). Except for valine, these results were replicated for all available metabolites in the Maastricht Study. In persons with obesity without diabetes, both liver and muscle IR show a circulating metabolic profile of elevated (branched-chain) amino acids, lactate, and triglycerides, and lower glycine levels, but only liver IR associates with lower ketone body levels and elevated ketogenic amino acids in circulation, suggestive of decreased ketogenesis. This knowledge might enhance developments of more targeted tissue-specific interventions to prevent progression to more severe disease stages.

Acute exposure to leucine modifies behavioral parameters and cholinergic activity in zebrafish

Maple Syrup Urine Disease (MSUD) is an autosomal recessive inherited disorder, caused by a deficiency on branched chain α-ketoacid dehydrogenase complex activity, resulting in accumulation of branched-chain amino acids (BCAA) (e.g. leucine). The treatment of MSDU patients increases survival time and quality of life. Thus, nowadays there are a crescent number of adolescents and adults with MSUD. Relevant studies have been reported behavioral alterations in these patients, i.e. high risk of chronic neuropsychiatric problems, such as attention deficit disorder, depression and anxiety. Moreover, MSUD is associated to neurotransmitters deficiency. Herein, we aimed to investigate whether the toxicity of leucine is associated to anxiety-like behavioral, using zebrafish acutely exposed to leucine as experimental model of MSUD. In addition, we evaluated the effects of high levels of leucine in the acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities, components of cholinergic neurotransmission system. Young zebrafish were exposed to 2 mM and 5 mM concentration of leucine for 24 h. After that, the animals were submitted to the Novel Tank test, having the brain collected to enzymatic determination. The exposure to both concentrations of leucine caused behavioral and brain cholinergic activity alterations in young zebrafish, indicating an anxiety-like behavior and cholinergic dysfunction. Therefore, this animal could be considered a promising organism to study the BCAA neurotoxic effects, which could help to a better comprehension of the behavioral and neurochemical alterations present in patients with MSUD.

Native Whey Induces Similar Adaptation to Strength Training as Milk, despite Higher Levels of Leucine, in Elderly Individuals.

Background: Large amounts of protein (40 g) or supplementing suboptimal servings of protein with leucine are able to overcome the anabolic resistance in elderly muscle. Our aim was to compare the effects of supplementation of native whey, high in leucine, with milk on gains in muscle mass and strength during a period of strength training, in elderly individuals. Methods: In this double-blinded, randomized, controlled study, a total of 30 healthy men and women received two daily servings of 20 g of either milk protein or native whey, during an 11-week strength training intervention. Muscle strength, lean mass, m. vastus lateralis thickness, muscle fiber area, and resting and post-exercise phosphorylation of p70S6K, 4E-BP1, and eEF-2 were assessed prior to and after the intervention period. Results: Muscle mass and strength increased, by all measures applied in both groups (p < 0.001), with no differences between groups (p > 0.25). p70S6K phosphorylation increased (~1000%, p < 0.045) 2 h after exercise in the untrained and trained state, with no differences between supplements. Total and phosphorylated mTORC-1 decreased after training. Conclusion: Supplementation with milk or native whey during an 11-week strength training period increased muscle mass and strength similarly in healthy elderly individuals.

Abstract 604: Biomarkers of amino acid metabolism and endometrial cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO)

Abstract Background: Incidence and mortality rates for endometrial cancer have steadily increased during the past decade. Beyond the well-known risk factors of obesity and unopposed estrogen menopausal hormone therapy (MHT), our understanding of the molecular etiology of this disease is limited and few biomarkers for risk are identified. To address this data gap, we explored circulating markers of amino acid metabolism and endometrial cancer risk—with specific interest in assessing whether the associations with branch chain amino acids (BCAAs) differed by known endometrial cancer risk factors. Methods: We used data from a nested case-control study within the screening arm of the PLCO trial (353 endometrial cancer cases, 353 controls, age 55-74 years at enrollment). We measured absolute concentrations of amino acid metabolism markers in pre-diagnostic serum using targeted mass spectrometry assays. Conditional and unconditional logistic regression adjusted for potential confounders (and matching factors in the latter) was used to estimate associations between these circulating markers and endometrial cancer overall, by body mass index (BMI), and by MHT use at baseline. We evaluated heterogeneity across these groups via likelihood ratio tests (p for interaction [p-int]). Results: In the full population, associations with endometrial cancer were generally masked/not identified, but we noted substantial effect modification by MHT use and BMI. A doubling in endometrial cancer risk was suggested with the highest concentrations of BCAAs, but only among women not using MHT (odds ratio and 95% confidence interval for the highest quintile [Q5] versus lowest [Q1]: leucine 1.87, 0.91–3.83; isoleucine 2.44, 1.17–5.09; and valine 1.86, 0.89–3.87; p-int &amp;lt;0.15 for all). We similarly noted that high levels of leucine (Q5 v. Q1: 3.26, 0.96–11.08, p-int 0.39) and valine (Q5 v. Q1: 6.40, 1.49–27.47, p-int 0.08) were associated with risk among obese women, but not those with normal BMIs. The highest levels of 3-hydroxyisobutyrate, a bioactive valine precursor, doubled risk among non-MHT users (CI 1.09–4.51, p-int &amp;lt;0.05) and quadrupled it among obese women (CI 1.45–14.86, p-int 0.33). High proline levels were associated with 4- to 7-fold increases in risk among non-MHT users (CI 1.68–10.01) and obese women (CI 2.11–26.81), respectively (p-int&amp;lt;0.05 for both). Conclusions: Our findings suggest that the regulation of BCAA metabolism may be involved in endometrial carcinogenesis, but this influence depends on other risk factors for the disease. Use of MHT overshadowed potential risks with most markers evaluated, and we identified increased risks associated with a variety of markers only among obese women. Amino acids play crucial roles in cellular energy metabolism and our results highlight the importance of finding ways to maintain and improve metabolic health in postmenopausal women. Citation Format: Kara A. Michels, Stephanie J. Weinstein, Nicolas Wentzensen, Ruth M. Pfeiffer, Britton Trabert. Biomarkers of amino acid metabolism and endometrial cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 604.

NMR-based metabolomics approach to investigate the distribution characteristics of metabolites in Dioscorea opposita Thunb. cv. Tiegun

Dioscorea opposita Thunb. cv. Tiegun (DTT), a type of homologous medicinal plant, is commonly used as food in daily life. However, there has always been confusion regarding removal of the peel, as the nutrient metabolite composition of the peel is unclear. Here, a nuclear magnetic resonance (NMR)-based metabolomics approach was used to determine the metabolite distribution in DTT exclude-peel and peel. Thirteen characteristic metabolites with statistical significance were identified and compared using multivariate, univariate and cluster analyses. The results demonstrated that the peel contained the higher levels of α-glucose, batatasin IV, batatasin I, asparagine, β-glucose, protodioscin, threonine, protogracillin, dioscin, and β-sitosteryl acetate, and the samples without the peel had the higher levels of leucine, glutamine and alanine. This study provided scientific data for understanding the distribution characteristics of metabolites in DTT samples, promoting reasonable consumption of DTT.

Alterations in the metabolism of phospholipids, bile acids and branched-chain amino acids predicts development of type 2 diabetes in black South African women: a prospective cohort study

BackgroundSouth Africa (SA) has the highest global projected increase in diabetes risk. Factors typically associated with insulin resistance and type 2 diabetes risk in Caucasians are not significant correlates in black African populations. Therefore, we aimed to identify circulating metabolite patterns that predict type 2 diabetes development in this high-risk, yet understudied SA population. MethodsWe conducted a prospective cohort study in black SA women with normal glucose tolerance (NGT). Participants were followed for 13 years and developed (i) type 2 diabetes (n = 20, NGT-T2D), (ii) impaired glucose tolerance (IGT) (n = 27, NGT-IGT), or (iii) remained NGT (n = 28, NGT-NGT). Mass-spectrometry based metabolomics and multivariate analyses were used to elucidate metabolite patterns at baseline and at follow-up that were associated with type 2 diabetes development. ResultsMetabolites of phospholipid, bile acid and branched-chain amino acid (BCAA) metabolism, differed significantly between the NGT-T2D and NGT-NGT groups. At baseline: the NGT-T2D group had i) a higher lysophosphatidylcholine:lysophosphatidylethanolamine ratio containing linoleic acid (LPC(C18:2):LPE(C18:2)), ii) lower proliferation-related bile acids (ursodeoxycholic- and chenodeoxycholic acid), iii) higher levels of leucine and its catabolic intermediates (ketoleucine and C5-carnitine), compared to the NGT-NGT group. At follow-up: the NGT-T2D group had i) lower LPC(C18:2) levels, ii) higher apoptosis-related bile acids (deoxycholic- and glycodeoxycholic acid), and iii) higher levels of all BCAAs and their catabolic intermediates. ConclusionsChanges in lysophospholipid metabolism and the bile acid pool occur during the development of type 2 diabetes in black South African women. Further, impaired leucine catabolism precedes valine and isoleucine catabolism in the development of type 2 diabetes. These metabolite patterns can be useful to identify and monitor type 2 diabetes risk >10 years prior to disease onset and provide insight into the pathophysiology of type 2 diabetes in this high risk, but under-studied population.

Native whey protein with high levels of leucine results in similar post-exercise muscular anabolic responses as regular whey protein: a randomized controlled trial

BackgroundProtein intake is essential to maximally stimulate muscle protein synthesis, and the amino acid leucine seems to possess a superior effect on muscle protein synthesis compared to other amino acids. Native whey has higher leucine content and thus a potentially greater anabolic effect on muscle than regular whey (WPC-80). This study compared the acute anabolic effects of ingesting 2 × 20 g of native whey protein, WPC-80 or milk protein after a resistance exercise session.MethodsA total of 24 young resistance trained men and women took part in this double blind, randomized, partial crossover, controlled study. Participants received either WPC-80 and native whey (n = 10), in a crossover design, or milk (n = 12). Supplements were ingested immediately (20 g) and two hours after (20 g) a bout of heavy-load lower body resistance exercise. Blood samples and muscle biopsies were collected to measure plasma concentrations of amino acids by gas-chromatography mass spectrometry, muscle phosphorylation of p70S6K, 4E–BP1 and eEF-2 by immunoblotting, and mixed muscle protein synthesis by use of [2H5]phenylalanine-infusion, gas-chromatography mass spectrometry and isotope-ratio mass spectrometry. Being the main comparison, differences between native whey and WPC-80 were analysed by a one-way ANOVA and comparisons between the whey supplements and milk were analysed by a two-way ANOVA.ResultsNative whey increased blood leucine concentrations more than WPC-80 and milk (P < 0.05). Native whey ingestion induced a greater phosphorylation of p70S6K than milk 180 min after exercise (P = 0.03). Muscle protein synthesis rates increased 1–3 h hours after exercise with WPC-80 (0.119%), and 1–5 h after exercise with native whey (0.112%). Muscle protein synthesis rates were higher 1–5 h after exercise with native whey than with milk (0.112% vs. 0.064, P = 0.023).ConclusionsDespite higher-magnitude increases in blood leucine concentrations with native whey, it was not superior to WPC-80 concerning effect on muscle protein synthesis and phosphorylation of p70S6K during a 5-h post-exercise period. Native whey increased phosphorylation of p70S6K and muscle protein synthesis rates to a greater extent than milk during the 5-h post exercise period.Trial registrationThis study was retrospectively registered at clinicaltrials.gov as NCT02968888.

Plasma amino acid and urine organic acid profiles of Filipino patients with maple syrup urine disease (MSUD) and correlation with their neurologic features

BackgroundMaple syrup urine disease (MSUD) is the most common inborn error of metabolism in the country. The cause of the neuropathology is still not well established although accumulation of branched chain amino acids (BCAA) and alteration in large neutral amino acids (LNAA) as well as energy deprivation are suggested. It is therefore the aim of this study to determine the plasma amino acid and urine organic acid profiles of patients with MSUD and correlate the findings with their neurologic features. MethodologyTwenty six Filipino patients with MSUD were studied in terms of their plasma amino acid and urine organic acid profiles. Their results were compared with 26 age and sex matched controls. The neurologic features were correlated with the results of the plasma amino acids and urine organic acids. ResultsMajority of the patients with MSUD had developmental delay/intellectual disability (88%), speech delay (69%), and seizures (65%). Their amino acid profiles revealed low glutamine and alanine with high levels of leucine, isoleucine, phenylalanine, threonine and alloisoleucine compared to controls (p<0.05). The urine organic acids showed significantly elevated excretion of the branched chain ketoacids and succinate (p<0.05). However there were no biochemical markers that correlated significantly with the neurologic features. ConclusionThe findings suggest that there could still be altered LNAA metabolism among patients with MSUD when the BCAAs are elevated. Although the biochemical findings were not significantly correlated with the neurologic features, the study showed that prevention and avoidance of neurologic disturbances may still rely primarily on early diagnosis and prompt institution of treatment, along with strict compliance with the dietary regimen and maintenance of good metabolic control over time.