Increasing dietary leucine intake reduces diet-induced obesity and improves glucose and cholesterol metabolism in mice via multimechanisms

Exploring the Health Effects of New Additive- and Allergen-Free Reformulated Cooked Meat Products: Consumer Survey, Clinical Trial, and Perceived Satiety

BACKGROUND

Consumers are increasingly interested in healthier, less processed food products, driving the meat industry to improve the quality and health benefits of its offerings. Growing concerns about additives and allergens have encouraged the replacement of these ingredients with natural alternatives, presenting both challenges and opportunities. However, consumer rejection of additives and the actual health effects of their replacement remain poorly understood. In previous work, two new meat products-cooked turkey breast and cooked ham-were developed, where additives and allergens were replaced with natural extracts. These products demonstrated potential health benefits in vitro, including improvements in protein quality and microbiota composition.

METHODS

This study assessed consumer perceptions of additives through a survey and evaluated the two new meat products in a double-blind, randomized clinical trial conducted over a 5-week period. Biomarkers of interest were measured in blood, faeces, and urine samples at baseline and at the end of this study. Additionally, a separate study tested the satiating effect of these products using VAS score surveys.

RESULTS

The additive perception survey revealed that consumers associate additive-free products with being more natural and less harmful to health, with differences observed based on age, gender, and knowledge of additives. In the clinical trial, both the intervention and control groups showed significant decreases in serum levels of ox-LDL and GPx, with no differences between the groups. However, significant differences between the groups were found in inflammation markers TNF-α and IL-1β. Furthermore, the intervention group exhibited a significant reduction in nitrate excretion and a decrease in nitrification-related gut bacteria. Finally, the reformulated products demonstrated a satiating effect, reducing hunger.

CONCLUSIONS

These findings suggest that the new additive- and allergen-free reformulated meat products may offer potential oxidative and anti-inflammatory benefits to consumers.

N-acetyl-l-leucine lowers pS129-synuclein and improves synaptic function in models of Parkinson's disease

N-acetyl-L-leucine (NALL), a derivative of the branched-chain amino acid leucine, has shown therapeutic potential in neurodegenerative diseases, including in prodromal stages of Parkinson's disease (PD). However, the mechanism of its protective effects has been largely unknown. Using discovery-based proteomics, we found that treatment with NALL led to upregulation of lysosomal, mitochondrial, and synaptic proteins in PD patient-derived dopaminergic neurons. NALL reduced levels of pathological pS129-alpha-synuclein in dopaminergic neurons from patients harboring GBA1 or LRRK2 mutations. This decrease in pS129-syn was dependent on serine protease HTRA1 that was induced by NALL treatment of dopaminergic neurons. NALL also upregulated expression of wild-type parkin in both GBA1 and LRRK2 mutant neurons, leading to an increase in functional dopamine transporter and synaptic membrane-associated synaptojanin-1, suggesting improved synaptic function. Furthermore, NALL treatment of mutant LRRK2R1441C knock-in mice led to decreased pS129-alpha-synuclein, increased parkin and improved dopamine-dependent motor learning deficits. These findings highlight the therapeutic potential of NALL in PD by its protective effects on α-synuclein pathology and synaptic function in vulnerable dopaminergic neurons.

Harnessing Hemp (Cannabis sativa L.) Seed Cake Proteins: From Concentrate Production to Enhanced Choux Pastry Quality

This study explores the production and valorization of hemp seed cake protein concentrate (HPC) as a functional ingredient to enhance the nutritional quality and sensory attributes of choux pastry products, specifically éclairs. By integrating varied concentrations of HPC (0%, 1%, 5%, 10%, 15%, and 20%) into traditional formulations, the physicochemical properties, proximate composition, amino acid profile, and sensory characteristics of the resulting pastries were assessed. Sensory attributes were assessed using the check-all-that-apply (CATA) method, where a trained panel selected applicable descriptors from a predefined list. Results indicated that the incorporation of HPC significantly increased protein content from 8.23% in the control sample (HPC0%) to 11.32% in the HPC20% formulation and improved moisture retention, leading to greater exterior and interior éclairs volume, increasing from 42.15 cm3 to 51.5 cm3 and from 18.34 cm3 to 38.47 cm3, respectively. Furthermore, sensory evaluation revealed pronounced differences in attributes such as flavor, appearance, and mouthfeel, with optimal sensory profiles noted at 10% HPC inclusion. The amino acid analysis demonstrated a balanced composition, particularly of essential amino acids, emphasizing HPC's potential as a valuable protein source, with significant contributions from leucine (8.17 g/100 g protein), isoleucine (5.56 g/100 g protein), and phenylalanine (6.31 g/100 g protein), as well as notable levels of immunoactive amino acids such as arginine (10.92 g/100 g protein) and glutamic acid (20.16 g/100 g protein). These findings highlight the significant nutritional benefits of HPC enrichment, supporting the development of healthier bakery products and contributing to sustainable food practices within the industry.

Exploration of the Fasting Hypoglycemic Mechanism of Casein Hydrolysate Enriched with Glu/Gln and Glu/Gln-Containing Peptides in db/db Diabetic-like Mice Using Multiomics Analysis

The fasting hypoglycemic effect of casein hydrolysate (CH) was investigated in db/db diabetic-like mice using a multiomics integrated analysis of peptidome, transcriptome, and metabolome. Results showed that the oral administration of CH at a dose of 600 mg/kg/day for 4 weeks reduced the fasting blood glucose levels by 14.73 ± 9.77%, alleviated insulin resistance (HOMA-IR index) by 36.91 ± 22.62%, and mitigated hepatic damage in db/db diabetic-like mice. Hepatic differential metabolites after CH treatment were enriched in Glu-related metabolites, which acted as substrates for the TCA cycle, enhancing hepatic glucose consumption. The hepatic transcriptomic results revealed that CH treatment upregulated (p < 0.05) hub gene expressions of pparg and pik3cb, leading to an activation of the PPAR signaling pathway, further improving the insulin/PI3K/AKT signaling pathway. The hub gene expressions were highly correlated with Glu-related metabolites in multiomics integrated analysis. Glx/Glx-containing peptides (Glx represents Glu and Gln) in CH, as a dietary supplement to increase hepatic Glu-related metabolites, might be the key active component responsible for its hypoglycemic effect. Particularly, the supplement of Glx was confirmed to effectively (p < 0.05) enhance glucose consumption in hepatocytes. This provides a basis for the development of CHs as functional food.

De novo lipid synthesis in cardiovascular tissue and disease

Most tissues have the capacity for endogenous lipid synthesis. A crucial foundational pathway for lipid synthesis is de novo lipid synthesis (DNL), a ubiquitous and complex metabolic process that occurs at high levels in the liver, adipose and brain tissue. Under normal physiological conditions, DNL is vital in converting excess carbohydrates into fatty acids. DNL is linked to other pathways, including the endogenous synthesis of phospholipids and sphingolipids. However, abnormal lipid synthesis can contribute to various pathologies and clinical conditions. Experimental studies involving dietary restriction and in vivo genetic modifications provide compelling evidence demonstrating the significance of lipid synthesis in maintaining normal cardiovascular tissue function. Similarly, clinical investigations suggest altered lipid synthesis can harm cardiac and arterial tissues, thereby influencing cardiovascular disease (CVD) development and progression. Consequently, there is increased interest in exploring pharmacological interventions that target lipid synthesis metabolic pathways as potential strategies to alleviate CVD. Here we review the physiological and pathological impact of endogenous lipid synthesis and its implications for CVD. Since lipid synthesis can be targeted pharmacologically, enhancing our understanding of the molecular and biochemical mechanisms underlying lipid generation and cardiovascular function may prompt new insights into CVD and its treatment.

BCKDH kinase promotes hepatic gluconeogenesis independent of BCKDHA

Elevated circulating branched-chain amino acids (BCAAs) are tightly linked to an increased risk in the development of type 2 diabetes mellitus. The rate limiting enzyme of BCAA catabolism branched-chain α-ketoacid dehydrogenase (BCKDH) is phosphorylated at E1α subunit (BCKDHA) by its kinase (BCKDK) and inactivated. Here, the liver-specific BCKDK or BCKDHA knockout mice displayed normal glucose tolerance and insulin sensitivity. However, knockout of BCKDK in the liver inhibited hepatic glucose production as well as the expression of key gluconeogenic enzymes. No abnormal gluconeogenesis was found in mice lacking hepatic BCKDHA. Consistent with the vivo results, BT2-mediated inhibition or genetic knockdown of BCKDK decreased hepatic glucose production and gluconeogenic gene expressions in primary mouse hepatocytes while BCKDK overexpression exhibited an opposite effect. Whereas, gluconeogenic gene expressions were not altered in BCKDHA-silenced hepatocytes. Mechanistically, BT2 treatment attenuated the interaction of cAMP response element binding protein (CREB) with CREB-binding protein and promoted FOXO1 protein degradation by increasing its ubiquitination. Our findings suggest that BCKDK regulates hepatic gluconeogenesis through CREB and FOXO1 signalings, independent of BCKDHA-mediated BCAA catabolism.

High gestational leucine level dampens WDPCP/MAPK signaling to impair the EMT and migration of cardiac microvascular endothelial cells in congenital heart defects

Congenital heart defects (CHDs) represent one of the most prevalent categories of neonatal defects, and maternal dietary patterns have been linked to the risk of these conditions. Branched-chain amino acids (BCAAs), particularly leucine, are essential for various metabolic and physiological processes involved in heart development. In this study, we examined the molecular mechanisms through which elevated levels of leucine induce defects in cardiac microvascular endothelial cells. We collected plasma samples from healthy controls and neonatal patients with CHDs, employed a high-leucine diet for pregnant female mice, and applied high-leucine treatment in human cardiac microvascular endothelial cells (HCMECs). The impacts of high-leucine levels on WD Repeat Containing Planar Cell Polarity Effector (WDPCP)/MAPK signaling axis were investigated in the cell and animal models. We reported heightened plasma leucine levels in neonatal patients with CHDs and observed that a high-leucine diet in pregnant mice was associated with reduced expression of WDPCP and attenuated MAPK/ERK signaling. High-leucine treatment in HCMECs impaired epithelial-mesenchymal transition (EMT) and cell migration; however, overexpression of WDPCP or activation of MAPK exhibited a rescue effect. The upregulation of endomucin (EMCN) under high-leucine conditions contributed to the impaired EMT and migratory capacity of HCMECs, and the WDPCP/MAPK signaling axis regulated EMCN overexpression in response to high-leucine treatment. High levels of leucine in neonatal patients with CHDs may inhibit the WDPCP/MAPK axis, leading to an increase in EMCN expression that undermines the function of cardiac microvascular endothelial cells. These findings suggest the potential of targeting the WDPCP/MAPK axis as an intervention strategy for neonatal CHDs.

Metabolic Profiling Changes Induced by Fermented Blackberries in High-Fat-Diet-Fed Mice Utilizing Gas Chromatography-Mass Spectrometry Analysis

The aim of this study was to investigate the metabolic changes associated with the anti-obesity effects of fermented blackberry extracts in the liver tissues of high-fat-diet-fed mice using mass spectrometry-based metabolomics analysis. C57BL/6J mice were divided into eight groups: normal-diet-fed mice, high-fat-diet-fed mice, high-fat diet treated with blackberry extract, high-fat-diet mice treated with blackberry fermented by L. plantarum, and high-fat diet with blackberry fermented by L. brevis. After 12 weeks, the high-fat-diet group exhibited a greater increase in liver weight compared to the control group, and among the groups, the group administered with blackberry fermented with L. plantarum showed the most pronounced reduction in liver weight. As the primary organ responsible for amino acid metabolism, the liver is crucial for maintaining amino acid homeostasis. In our study, we observed that the levels of several essential amino acids, including isoleucine and valine, were decreased by the high-fat diet, and were recovered by administration of blackberry extract fermented with L. plantarum. Our results demonstrated the potential of blackberry extract fermented with L. plantarum as a functional material for metabolic disorders by restoring some of the amino acid metabolism disturbances induced by a high-fat diet.

Branched-chain amino acid supplementation drives dynamic changes in gut microbiota without impairing glucose and lipid homeostasis at the different stages of insulin resistance in mice on a high-fat diet

OBJECTIVE

The potential role of dietary branched-chain amino acids on circulating branched-chain amino acid levels and their relationship with metabolic health are complex, and the literature is inconsistent. We aimed to explore the dynamic effects of branched-chain amino acid supplementation on glucose and lipid homeostasis at different stages of insulin resistance in high-fat diet-fed mice.

METHODS

Male C57BL/6J mice were fed with a normal chow diet, high-fat diet, or high-fat diet supplemented with 100% branched-chain amino acids for 12 or 24 wk. Metabolic parameters and gut microbiota profiling were performed at these two time points.

RESULTS

High-fat diet feeding caused varying degrees of branched-chain amino acid metabolic disorders in two different stages of insulin resistance. Supplementing with branched-chain amino acids further exacerbated branched-chain amino acid accumulation in the early stage of insulin resistance (12 wk), while adding branched-chain amino acids did not further elevate branched-chain amino acid levels in the hyperglycemia and hyperinsulinemia stage (24 wk). Compared with the high-fat diet group, branched-chain amino acid supplementation did not affect body weight; liver total cholesterol and triacylglycerol levels; and serum glucose, insulin, total cholesterol, triacylglycerol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels as well as glucose tolerance at these two time points but triggered dynamic changes in the gut bacterial diversity and gut microbiota composition and abundance, especially in the genus associated with obesity and related metabolic disorders.

CONCLUSION

Dietary branched-chain amino acid supplementation drives dynamic changes in circulating branched-chain amino acid levels and gut microbiome without subsequent effects on glucose and lipid homeostasis in high-fat diet-induced obese mice within the parameters of our study.

Multiomics Analysis Reveals Leucine Deprivation Promotes Bile Acid Synthesis by Upregulating Hepatic CYP7A1 and Intestinal Turicibacter sanguinis in Mice

BACKGROUND

Leucine, a branched-chain amino acid, participates in the regulation of lipid metabolism and the composition of the intestinal microbiota. However, the related mechanism remains unclear.

OBJECTIVES

Here, we aimed to reveal the potential mechanisms by which hepatic CYP7A1 (a rate-limiting enzyme for bile acid [BA] synthesis) and gut microbiota coregulate BA synthesis under leucine deprivation.

METHODS

To this end, 8-wk-old C57BL/6J mice were fed with either regular diets or leucine-free diets for 1 wk. Then, we investigated whether secondary BAs were synthesized by Turicibacter sanguinis in 7-wk-old C57BL/6J germ-free mice gavaged with T. sanguinis for 2 wk by determining BA concentrations in the plasma, liver, and cecum contents using liquid chromatography-tandem mass spectrometry.

RESULTS

The results showed that leucine deprivation resulted in a significant increase in total BA concentration in the plasma and an increase in the liver, but no difference in total BA was observed in the cecum contents before and after leucine deprivation. Furthermore, leucine deprivation significantly altered BA profiles such as taurocholic acid and ω-muricholic acid in the plasma, liver, and cecum contents. CYP7A1 expression was significantly upregulated in the liver under leucine deprivation. Leucine deprivation also regulated the composition of the gut microbiota; specifically, it significantly upregulated the relative abundance of T. sanguinis, thus enhancing the conversion of primary BAs into secondary BAs by intestinal T. sanguinis in mice.

CONCLUSIONS

Overall, leucine deprivation regulated BA profiles in enterohepatic circulation by upregulating hepatic CYP7A1 expression and increasing intestinal T. sanguinis abundance. Our findings reveal the contribution of gut microbiota to BA metabolism under dietary leucine deprivation.

The role of branched-chain amino acids and their downstream metabolites in mediating insulin resistance

Elevated levels of circulating branched-chain amino acids (BCAAs) and their associated metabolites have been strongly linked to insulin resistance and type 2 diabetes. Despite extensive research, the precise mechanisms linking increased BCAA levels with these conditions remain elusive. In this review, we highlight the key organs involved in maintaining BCAA homeostasis and discuss how obesity and insulin resistance disrupt the intricate interplay among these organs, thus affecting BCAA balance. Additionally, we outline recent research shedding light on the impact of tissue-specific or systemic modulation of BCAA metabolism on circulating BCAA levels, their metabolites, and insulin sensitivity, while also identifying specific knowledge gaps and areas requiring further investigation. Finally, we summarize the effects of BCAA supplementation or restriction on obesity and insulin sensitivity.

Metabolic liability for weight gain in early adulthood

While weight gain is associated with a host of chronic illnesses, efforts in obesity have relied on single "snapshots" of body mass index (BMI) to guide genetic and molecular discovery. Here, we study >2,000 young adults with metabolomics and proteomics to identify a metabolic liability to weight gain in early adulthood. Using longitudinal regression and penalized regression, we identify a metabolic signature for weight liability, associated with a 2.6% (2.0%-3.2%, p = 7.5 × 10-19) gain in BMI over ≈20 years per SD higher score, after comprehensive adjustment. Identified molecules specified mechanisms of weight gain, including hunger and appetite regulation, energy expenditure, gut microbial metabolism, and host interaction with external exposure. Integration of longitudinal and concurrent measures in regression with Mendelian randomization highlights the complexity of metabolic regulation of weight gain, suggesting caution in interpretation of epidemiologic or genetic effect estimates traditionally used in metabolic research.

Leucine regulates lipid metabolism in adipose tissue through adipokine-mTOR-SIRT1 signaling pathway and bile acid-microbe axis in a finishing pig model

This study was conducted to explore the regulatory mechanism of leucine (Leu) on lipid metabolism of finishing pigs. Twenty-four Duroc × Landrace × Large cross pigs with an average body weight of 68.33 ± 0.97 kg were randomly allocated into 3 treatment groups with 8 replicates per group (1 pig per replicate). The dietary treatments were as follows: control group (CON), 0.25% Leu group and 0.50% Leu group. The experimental period was 42 d. The results showed as follows. (1) Compared with the CON, 0.25% and 0.50% Leu increased (P < 0.01) the average daily gain (ADG), while the average backfat thickness (ABT) and the ratio of feed intake to body weight gain (F:G ratio) were decreased (P < 0.05). (2) In the 0.25% Leu group, the relative mRNA expression levels of sterol regulatory element binding protein-1c (SREBP1c), recombinant fatty acid transport protein 1 (FATP1), chemerin and peroxisome proliferator-activated receptor γ (PPARγ) were decreased but the level of fatty acid binding protein 4 (FABP4) and fatty acid translocase (FAT/CD36) were increased in backfat tissue. In the 0.25% Leu group, the protein levels of p-Rictor, p-Raptor, p-eIF4E-binding protein 1 (p-4EBP1), p-silent mating type information regulator 2 homolog 1 (p-SIRT1) and acetylation ribosome s6 protein kinase 1 (Ac-S6K1) were increased (P < 0.05). (3) Compared to the CON, the diversity of gut microbiota in the 0.25% Leu group was increased. Principal component analysis showed that the relative abundance of Bacteroidetes, Lactobacillus and Desulfovibrio was higher in the 0.25% Leu group than the CON, but the relative abundance of Firmicutes, Treponema and Shigella was lower than in the CON (P < 0.05). (4) Four different metabolites were screened out from the serum of finishing pigs including allolithocholic acid (alloLCA), isolithocholic acid (isoLCA), ursodeoxycholic acid (UDCA) and hyodeoxycholic acid (HDCA), which correlate to various degrees with the above microorganisms. In conclusion, Leu could promote adipose tissue lipolysis of finishing pigs through the mTOR-SIRT1 signaling pathway, and S6K1 is acetylated at the same time, and the interaction between gut microbiota and bile acid metabolism is also involved.

Lipodystrophy in methylmalonic acidemia associated with elevated FGF21 and abnormal methylmalonylation

A distinct adipose tissue distribution pattern was observed in patients with methylmalonyl-CoA mutase deficiency, an inborn error of branched-chain amino acid (BCAA) metabolism, characterized by centripetal obesity with proximal upper and lower extremity fat deposition and paucity of visceral fat, that resembles familial multiple lipomatosis syndrome. To explore brown and white fat physiology in methylmalonic acidemia (MMA), body composition, adipokines, and inflammatory markers were assessed in 46 patients with MMA and 99 matched controls. Fibroblast growth factor 21 levels were associated with acyl-CoA accretion, aberrant methylmalonylation in adipose tissue, and an attenuated inflammatory cytokine profile. In parallel, brown and white fat were examined in a liver-specific transgenic MMA mouse model (Mmut-/- TgINS-Alb-Mmut). The MMA mice exhibited abnormal nonshivering thermogenesis with whitened brown fat and had an ineffective transcriptional response to cold stress. Treatment of the MMA mice with bezafibrates led to clinical improvement with beiging of subcutaneous fat depots, which resembled the distribution seen in the patients. These studies defined what we believe to be a novel lipodystrophy phenotype in patients with defects in the terminal steps of BCAA oxidation and demonstrated that beiging of subcutaneous adipose tissue in MMA could readily be induced with small molecules.

The impact of leucine supplementation on body composition and glucose tolerance following energy restriction: an 8-week RCT in adults at risk of the metabolic syndrome

BACKGROUND

L-Leucine (Leu) supplementation may benefit fat-free mass (FFM) per se and glucose metabolism.

OBJECTIVES

To determine whether Leu supplementation during energy restriction blunted the loss of FFM, enhanced the loss of fat mass (FM) and improved glucose tolerance.

DESIGN

Thirty-seven adults, aged 20-65 years, with increased waist circumference and at least one other metabolic syndrome (MetS) component, were selected. We employed a two-arm parallel, double blind, randomized control trial (RCT) design. Participants were randomly assigned to an intervention group (leucine - 3 g/d) or placebo (lactose - 2.67 g/d), while following an individualised energy restricted diet for an 8-week period. Detailed body composition (DEXA), oral glucose tolerance test (OGTT), insulin and components of MetS were measured before and after the trial. Analysis of covariance (ANCOVA) assessed the effect of Leu on an intention-to-treat (ITT) principle. Bootstrapping method with 1000 bootstrap samples was used to derive parameter estimates, standard errors, p-values, and 95% confidence intervals for all outcomes.

RESULTS

Adjusted for baseline values and other covariates, FFM (p = 0.045) and lean tissue mass (LTM) (p = 0.050) were significantly higher following Leu. These outcomes were modified by a significant treatment x sex interaction that indicated Leu had the greater effect in men. However, on adjustment for body composition changes, there was no difference in insulin sensitivity, oral glucose tolerance, or change in MetS components following Leu.

CONCLUSION

Short-term leucine supplementation during energy restriction resulted in a greater preservation of FFM and LTM particularly in men, but did not impact glucose metabolism.

Effects of Balsa Fish Skin Gelatin, Lentinula edodes Mushrooms, Soy Protein Isolate, and Starch on the Sensory Quality and Characterization of Physicochemical and Antioxidant Properties of New Sausage

Sausages are loved by people for their unique texture, satisfying chewiness, and pleasant flavor. However, in the production of sausages, red meat and a large amount of fat are mainly used, and long-term consumption will increase the risk of diseases such as obesity, heart disease, hypertension, and cancer. Our previous studies have shown that the intake of red meat and fat can be reduced through the replacement of lean meat and fat in sausages by Lentinula edodes and Pleaurotus eryngii mushrooms, but this will lead to the deterioration of the gel of sausage products and seriously affect the sensory quality of sausages. In this study, the response surface method was used to optimize the amount of balsa fish skin gelatin, soy protein isolate, and starch added to, and the proportion of Lentinula edodes mushrooms replacing lean meat in, the new sausage, with Pleaurotus eryngii mushrooms replacing fat. The results show that Lentinula edodes mushrooms replaced 36.1% of the lean meat, and the addition of 0.96% balsa fish skin gelatin, 10.61% starch, and 9.94% soy protein isolate resulted in the highest sensory score and the sensory quality being the closest to that of traditional sausages. Compared with the control group, this novel sausage exhibits characteristics such as lower fat and saturated fatty acid content, reduced energy levels, and higher levels of amino acids (aspartic acid, glutamic acid, cysteine, methionine, and proline) and polyunsaturated fatty acids. The total phenolic content of the novel sausage is 12.52 times higher than that of the control. In comparison with the control group, the novel sausage demonstrates a 65.58% increase in DPPH radical scavenging activity and a 3.88-fold improvement in ABTS+ radical scavenging activity. These findings highlight the outstanding antioxidant performance of the novel sausage. This study provides new ideas for improving the sensory quality of new sausages, promoting the healthy development of the sausage industry, and promoting the high-value utilization of edible mushrooms.

Dietary leucine supplementation improves growth performance, metabolic responses of liver via GCN2/ATF4, and insulin signaling pathways in largemouth bass (Micropterus salmoides)

An 8-week growth experiment was conducted to investigate the effects of dietary leucine on growth performance, body composition, and gene expression of hepatic nutrient metabolism in the largemouth bass (Micropterus salmoides). Six isonitrogenous (49.87%) diets with graded leucine levels (2.62, 3.07, 3.60, 3.87, 4.20, 4.71% of dry diet) were fed to triplicate groups with 20 juvenile fish (20.00 ± 0.13 g). The results revealed that the specific growth rate (SGR) and weight gain (WG) increased significantly with increasing dietary leucine levels, reached their maximal value in the Leu-4.20% groups, and then decreased slightly. Although the feed conversion ratio (FCR) showed decreasing trends, no significant difference was detected. Leucine supplementation significantly improved the content of body protein and total plasma protein (TP). Additionally, a higher expression level of target of rapamycin (TOR) and ribosomal protein S6 (S6) mRNA was observed in the Leu-3.87% and Leu-4.20% diets, whereas the GCN2 (general control nonderepressible2 kinase) and AFT4 (activating transcription factor 4) mRNA expression levels were suppressed. The lipid content of the body was not influenced by leucine levels, whereas the content of total triglyceride (TG) first decreased significantly with increasing dietary leucine levels from 2.62 to 3.87% and then increased with increasing leucine levels (4.20% to 4.71%). The total cholesterol (TC) and low-density lipoproteins (LDL) trended in a similar direction but did not achieve statistical significance (P > 0.05). The expression of insulin receptor substrate 1 (IRS-1) was significantly elevated by dietary leucine levels, while protein kinase B (AKT) and phosphatidylinositol 3-kinase (PI3K) expression was inconsistently upregulated. Furthermore, leucine supplementation decreased plasma glucose and hepatic glycogen contents, and the expression levels of glucokinase (GK), phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6-phosphatase (G6pase) were significantly inhibited at 4.20% and 4.71% leucine diets. Analyses of the change in SGR and FCR using the quadratic regression model estimated that the optimum dietary leucine requirement of juvenile largemouth bass was 4.42% and 4.63% of the dry diet (8.86% and 9.28% of dietary protein), respectively.

Branched-chain amino acids prevent obesity by inhibiting the cell cycle in an NADPH-FTO-m6A coordinated manner

Obesity has become a major health crisis in the past decades. Branched-chain amino acids (BCAA), a class of essential amino acids, exerted beneficial health effects with regard to obesity and its related metabolic dysfunction, although the underlying reason is unknown. Here, we show that BCAA supplementation alleviates high-fat diet (HFD)-induced obesity and insulin resistance in mice and inhibits adipogenesis in 3T3-L1 cells. Further, we find that BCAA prevent the mitotic clonal expansion (MCE) of preadipocytes by reducing cyclin A2 (CCNA2) and cyclin-dependent kinase 2 (CDK2) expression. Mechanistically, BCAA decrease the concentration of nicotinamide adenine dinucleotide phosphate (NADPH) in adipose tissue and 3T3-L1 cells by reducing glucose-6-phosphate dehydrogenase (G6PD) expression. The reduced NADPH attenuates the expression of fat mass and obesity-associated (FTO) protein, a well-known m6A demethylase, to increase the N6-methyladenosine (m6A) levels of Ccna2 and Cdk2 mRNA. Meanwhile, the high m6A levels of Ccna2 and Cdk2 mRNA are recognized by YTH N6-methyladenosine RNA binding protein 2 (YTHDF2), which results in mRNA decay and reduction of their protein expressions. Overall, our data demonstrate that BCAA inhibit obesity and adipogenesis by reducing CDK2 and CCNA2 expression via an NADPH-FTO-m6A coordinated manner in vivo and in vitro, which raises a new perspective on the role of m6A in the BCAA regulation of obesity and adipogenesis.

Association between type 2 diabetes and branched chain amino acids (BCAA); a case-control study

Background

Several amino acids and their derivatives have been implicated in insulin resistance (IR) and Type 2 Diabetes Mellitus (T2DM). This research sought to establish a relationship between the dietary levels of branched-chain amino acids (BCAA) and the risk of T2DM.

Methods

This case-control study was carried out on 4200 participants consisting of 589 people with T2DM and 3611 non-diabetic aged 35 to 70 years residents in Sabzevar, Iran. Data on the economic-social, employment status, medical history, lifestyle, and sleep habits were collected via interview. The food frequency questionnaire (FFQ) was used to check the nutritional status. Participants' dietary BCAA consumption was estimated using Nutritionist IV software.

Results

A significant negative association between the incidence of T2DM and the dietary levels of BCAAs after adjustment for age and sex (OR = 0.972, CI 95%:0.648-0.996, P = 0.022). The negative association remained significant after additional adjustments for body mass index (BMI) and physical activity (OR = 0.967, CI 95%: 0.943-0.992, P = 0.010). Interestingly, a positive association was found between T2DM and total BCAAs (OR = 1.067, CI 95%: 1.017-1.119, P = 0.008), Isoleucine (OR = 1.248, CI 95%: 1.043-1.494, P = 0.016), Leucine (OR = 1.165, CI 95%: 1.046-1.299, P = 0.006) and Valine (OR = 1.274, CI 95%: 1.088-1.492, P = 0.003) after further adjustment for calorie intake.

Conclusions

Our results demonstrate branched-chain amino acids (BCAAs) including isoleucine, leucine, and valine are negatively associated with the incidence of type 2 diabetes (T2DM) after adjusting for age and sex, BMI, and physical activity. However, adjusting for calorie intake reversed the association between T2DM and BCAAs. These findings suggest that the association between BCAAs and T2DM may be influenced by calorie intake. Future longitudinal studies are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01247-9.

Metabolomic analysis of serum short-chain fatty acid concentrations in a mouse of MPTP-induced Parkinson's disease after dietary supplementation with branched-chain amino acids

The gut microbiota and microbial metabolites influence the enteric nervous system and the central nervous system via the microbial-gut-brain axis. Increasing body of evidence suggests that disturbances in the metabolism of peripheral branched-chain amino acids (BCAAs) can contribute to the development of neurodegenerative diseases through neuroinflammatory signaling. Preliminary research has shown that longitudinal changes in serum amino acid levels in mouse models of Parkinson's disease (PD) are negatively correlated with disease progression. Therefore, the aim of the present study was to determine the changes in serum levels of short-chain fatty acids (SCFAs) in a mouse model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD after dietary BCAA supplementation. In our research, gas chromatography-mass spectrometry was used to detect serum SCFA concentrations. The data were then analyzed with principal component analysis and orthogonal partial least squares discriminant analysis. Finally, the correlations of serum SCFA levels with gut and motor function in MPTP-induced PD mice were explored. Propionic acid, acetic acid, butyric acid, and isobutyric acid concentrations were elevated in MPTP + H-BCAA mice compared with MPTP mice. Propionic acid concentration was increased the most, while the isovaleric acid concentration was decreased. Propionic acid concentration was positively correlated with fecal weight and water content and negatively correlated with the pole-climbing duration. In conclusion, these results not only suggest that propionic acid may be a potential biomarker for PD, but also indicate the possibility that PD may be treated by altering circulating levels of SCFA.

Research progress in the role and mechanism of Leucine in regulating animal growth and development

Leucine, a branched-chain amino acid, is essential in regulating animal growth and development. Recent research has uncovered the mechanisms underlying Leucine's anabolic effects on muscle and other tissues, including its ability to stimulate protein synthesis by activating the mTORC1 signaling pathway. The co-ingestion of carbohydrates and essential amino acids enhances Leucine's anabolic effects. Moreover, Leucine has been shown to benefit lipid metabolism, and insulin sensitivity, making it a promising strategy for preventing and treating metabolic diseases, including type 2 diabetes and obesity. While emerging evidence indicates that epigenetic mechanisms may mediate Leucine's effects on growth and development, more research is needed to elucidate its mechanisms of action fully. Specific studies have demonstrated that Leucine promotes muscle growth and metabolic health in animals and humans, making it a promising therapeutic agent. However, it is essential to note that Leucine supplementation may cause digestive issues or interact with certain medications, and More study is required to determine definitively optimal dosages. Therefore, it is important to understand how Leucine interacts with other nutrients, dietary factors, and lifestyle habits to maximize its benefits. Overall, Leucine's importance in human nutrition is far-reaching, and its potential to prevent muscle loss and enhance athletic performance warrants further investigation.

Branched-chain amino acid modulation of lipid metabolism, gluconeogenesis, and inflammation in a finishing pig model: targeting leucine and valine

Branched-chain amino acids (BCAAs) play a regulatory role in adipogenesis and energy balance. Therefore, this study aimed to investigate the impact of BCAA supplements, especially leucine (Leu) and valine (Val) supplementation, on lipid metabolism and related disorders in a finishing pig model. The results demonstrated that Leu (1%) and Val decreased serum as well as hepatic lipid accumulation. Moreover, metabolomics and lipidomics analyses revealed that Leu and Val markedly downregulated the level of various lipid species in the liver. This outcome may be explained by Leu and Val promoting cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/hormone-sensitive triglyceride lipase (HSL) signaling pathways. Leu and Val altered the fatty acid composition in distinct adipose tissues and decreased the levels of inflammatory factors. Additionally, they significantly decreased back fat thickness, and the results of the fatty acid profiles demonstrated that Leu and Val significantly increased the levels of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) while decreasing those of saturated fatty acids (SFAs), especially in back fat and abdominal fat. Besides, Leu and Val restored glucose homeostasis by suppressing gluconeogenesis through the serine/threonine protein kinase (AKT)/transcription factor forkhead box O1 (FOXO1) signaling pathway in the liver and back fat. In summary, these results suggest that Leu and Val may serve as key regulators for modulating lipid metabolism and steatosis.

Metabolite profiles of diabetes mellitus and response to intervention in anti-hyperglycemic drugs

Type 2 diabetes mellitus (T2DM) has become a major health problem, threatening the quality of life of nearly 500 million patients worldwide. As a typical multifactorial metabolic disease, T2DM involves the changes and interactions of various metabolic pathways such as carbohydrates, amino acid, and lipids. It has been suggested that metabolites are not only the endpoints of upstream biochemical processes, but also play a critical role as regulators of disease progression. For example, excess free fatty acids can lead to reduced glucose utilization in skeletal muscle and induce insulin resistance; metabolism disorder of branched-chain amino acids contributes to the accumulation of toxic metabolic intermediates, and promotes the dysfunction of β-cell mitochondria, stress signal transduction, and apoptosis. In this paper, we discuss the role of metabolites in the pathogenesis of T2DM and their potential as biomarkers. Finally, we list the effects of anti-hyperglycemic drugs on serum/plasma metabolic profiles.

Effects of Mealworm Fermentation Extract and Soy Protein Mix Ratio on Hepatic Glucose and Lipid Metabolism in Obese-Induced Mice

Previous studies found that mealworm fermentation extract (TMP) reduced alcoholic hepatic steatogenesis. This study examined how the ratio of TMP and soy protein (SP) mix affected glucose and lipid metabolism in obese mice given a high-fat diet (HFD). Mice were given HFD supplemented with 100% SP or the following three ratios of TMP and SP mix for 12 weeks: 20% (S4T1), 40% (S3T2), and 60% (S2T3) TMP. When compared to the SP group, the S2T3 group had considerably lower body weight gain and food consumption. When compared to the SP group, the S2T3 group had slightly lower blood insulin and leptin levels, as well as a lower homeostasis model assessment of insulin resistance score. The use of TMP instead of SP reduced the size of epididymal adipose tissue cells. An increase in the extent of substitution of SP with TMP inhibited the gene expression of hepatic fructolysis/gluconeogenesis (KHK, ALDOB, DLD, and FBP1), lipogenesis (FAS, SCD1, CD36, and DGAT2), and its transcriptional factors (PPARγ and ChREBP). Furthermore, the S2T3 group dramatically reduced the expression of hepatic genes implicated in endoplasmic reticulum stress (PDI) and antioxidant defense (SOD1). The 60% TMP mix, in particular, reduced the expression of hepatic glucose and lipid metabolismrelated genes in HFD-fed mice. The manufacturing of functional processed goods may be accomplished by combining SP and TMP in a 2:3 ratio.

Dietary branched-chain amino acids intake, glycemic markers, metabolic profile, and anthropometric features in a community-based sample of overweight and obese adults

BACKGROUND

Existing research provides conflicting evidence regarding the relationship between estimated branched-chain amino acid (BCAA) intake and metabolic, glycemic markers, and anthropometric characteristics. This research seeks to examine the association between estimated dietary BCAA consumption and glycemic, and metabolic markers, as well as anthropometric parameters in adults classified as overweight or obese.

METHODS

In this cross-sectional analysis, we gathered data from 465 overweight and obese individuals aged between 18 and 37 years. To evaluate dietary data, we employed the food frequency questionnaire, and the BCAA content in foods was determined via the United States Department of Agriculture website. We utilized ELISA kits to measure fasting blood glucose (FBS) and lipid profile markers, and additionally calculated low-density lipoprotein (LDL) and insulin sensitivity markers. We assessed sociodemographic status, physical activity (PA), and anthropometric attributes through a method recognized as both valid and reliable. For statistical analysis, we conducted analyses of covariance (ANCOVA), making adjustments for variables including sex, PA, age, energy, and body mass index (BMI).

RESULTS

Upon adjusting for confounders, those in the highest tertiles of BCAA intake exhibited an increase in weight, BMI, waist circumference (WC), waist-to-hip ratio (WHR), and fat-free mass (FFM). Conversely, they demonstrated reduced fat mass (FM) (%) and FM (kg) compared to their counterparts in the lowest tertiles (P < 0.05). Additionally, there was a noted association between greater estimated BCAA intake and reduced LDL levels. Nonetheless, our findings did not reveal a significant relationship between dietary BCAA and glycemic indices.

CONCLUSIONS

From our findings, an increased estimated intake of BCAA seems to correlate with diminished serum LDL concentrations. To gain a more comprehensive understanding of this association, it is imperative that further experimental and longitudinal studies be conducted.

The Regulation and Secretion of Glucagon in Response to Nutrient Composition: Unraveling Their Intricate Mechanisms

Glucagon was initially regarded as a hyperglycemic substance; however, recent research has revealed its broader role in metabolism, encompassing effects on glucose, amino acids (AAs), and lipid metabolism. Notably, the interplay of glucagon with nutrient intake, particularly of AAs, and non-nutrient components is central to its secretion. Fasting and postprandial hyperglucagonemia have long been linked to the development and progression of type 2 diabetes (T2DM). However, recent studies have brought to light the positive impact of glucagon agonists on lipid metabolism and energy homeostasis. This review explores the multifaceted actions of glucagon, focusing on its regulation, signaling pathways, and effects on glucose, AAs, and lipid metabolism. The interplay between glucagon and other hormones, including insulin and incretins, is examined to provide a mechanistic understanding of its functions. Notably, the liver-α-cell axis, which involves glucagon and amino acids, emerges as a critical aspect of metabolic regulation. The dysregulation of glucagon secretion and its impact on conditions such as T2DM are discussed. The review highlights the potential therapeutic applications of targeting the glucagon pathway in the treatment of metabolic disorders.

Dietary supplementation with L-leucine reduces nitric oxide synthesis by endothelial cells of rats

This study tested the hypothesis that elevated L-leucine concentrations in plasma reduce nitric oxide (NO) synthesis by endothelial cells (ECs) and affect adiposity in obese rats. Beginning at four weeks of age, male Sprague-Dawley rats were fed a casein-based low-fat (LF) or high-fat (HF) diet for 15 weeks. Thereafter, rats in the LF and HF groups were assigned randomly into one of two subgroups (n = 8/subgroup) and received drinking water containing either 1.02% L-alanine (isonitrogenous control) or 1.5% L-leucine for 12 weeks. The energy expenditure of the rats was determined at weeks 0, 6, and 11 of the supplementation period. At the end of the study, an oral glucose tolerance test was performed on all the rats immediately before being euthanized for the collection of tissues. HF feeding reduced (P < 0.001) NO synthesis in ECs by 21% and whole-body insulin sensitivity by 19% but increased (P < 0.001) glutamine:fructose-6-phosphate transaminase (GFAT) activity in ECs by 42%. Oral administration of L-leucine decreased (P < 0.05) NO synthesis in ECs by 14%, increased (P < 0.05) GFAT activity in ECs by 35%, and reduced (P < 0.05) whole-body insulin sensitivity by 14% in rats fed the LF diet but had no effect (P > 0.05) on these variables in rats fed the HF diet. L-Leucine supplementation did not affect (P > 0.05) weight gain, tissue masses (including white adipose tissue, brown adipose tissue, and skeletal muscle), or antioxidative capacity (indicated by ratios of glutathione/glutathione disulfide) in LF- or HF-fed rats and did not worsen (P > 0.05) adiposity, whole-body insulin sensitivity, or metabolic profiles in the plasma of obese rats. These results indicate that high concentrations of L-leucine promote glucosamine synthesis and impair NO production by ECs, possibly contributing to an increased risk of cardiovascular disease in diet-induced obese rats.

Impact of a Whey Protein Hydrolysate Treated by Electrodialysis with Ultrafiltration Membrane on the Development of Metabolic Syndrome and the Modulation of Gut Microbiota in Mice

The development of Metabolic Syndrome (MetS) affects a large number of people around the world and represents a major issue in the field of health. Thus, it is important to implement new strategies to reduce its prevalence, and various approaches are currently under development. Recently, an eco-friendly technology named electrodialysis with ultrafiltration membrane (EDUF) was used successfully for the first time at a semi-industrial scale to produce three fractions concentrated in bioactive peptides (BPs) from an enzymatically hydrolyzed whey protein concentrate (WPC): the initial (F1), the final (F2) and the recovery fraction (F3), and it was demonstrated in vitro that F3 exhibited interesting DPP-IV inhibitory effects. Therefore, the present study aimed to evaluate the effect of each fraction on in vivo models of obesity. A daily dose of 312.5 mg/kg was administered to High Fat/High Sucrose diet (HFHS) induced C57BL6/J mice for eight weeks. The physiological parameters of each group and alterations of their gut microbiota by the fractions were assessed. Little effect of the different fractions was demonstrated on the physiological state of the mice, probably due to the digestion process of the BP content. However, there were changes in the gut microbiota composition and functions of mice treated with F3.

Glucolipid metabolism improvement in impaired glucose tolerance subjects consuming a Quinoa-based diet: a randomized parallel clinical trial

Purpose: To investigate the effects of quinoa on glucose and lipid metabolism, and the prognosis in people with impaired glucose tolerance. Methods: One hundred and thirty-eight patients diagnosed with impaired glucose tolerance following a glucose tolerance test in Guangzhou Cadre Health Management Center were selected and randomly divided into quinoa intervention and control groups, according to the digital table method. After 1 year of follow-up, the differences in blood glucose, blood lipid, glycosylated hemoglobin and other indicators were compared. The disease prognosis between the two groups was also compared. Results: The 2 h postprandial blood glucose, glycosylated hemoglobin, insulin resistance index, total cholesterol, low-density lipoprotein cholesterol, body mass index, waist circumference, systolic and diastolic blood pressure after intervention in the quinoa group were significantly lower than before intervention. In contrast, high-density lipoprotein cholesterol was higher than before intervention and is statistically significant (p < 0.05). After 1 year of follow-up, the control group's glycosylated hemoglobin and body mass index are higher than before intervention, and are statistically significant (p < 0.05). The 2 h postprandial blood glucose, glycosylated hemoglobin, insulin resistance index, body mass index, and mean diastolic blood pressure in the quinoa group are statistically significantly lower than in the control group, while high-density lipoprotein cholesterol is higher (p < 0.05). The rate of conversion to diabetes for participants in the quinoa group (7.8%) is statistically significantly lower than in the control group (20.3%) (χ2 = 12.760, p = 0.002). Logistic regression analysis showed that quinoa consumption is a protective factor against delaying the progression of diabetes (p < 0.05). Conclusion: Adding quinoa to staple food intake can reduce postprandial blood glucose, and improve lipid metabolism and insulin resistance, delaying the progression of diabetes in people with impaired glucose tolerance.

Obesity, Gut Microbiota, and Metabolome: From Pathophysiology to Nutritional Interventions

Obesity is a disorder identified by an inappropriate increase in weight in relation to height and is considered by many international health institutions to be a major pandemic of the 21st century. The gut microbial ecosystem impacts obesity in multiple ways that yield downstream metabolic consequences, such as affecting systemic inflammation, immune response, and energy harvest, but also the gut-host interface. Metabolomics, a systematized study of low-molecular-weight molecules that take part in metabolic pathways, represents a serviceable method for elucidation of the crosstalk between hosts' metabolism and gut microbiota. In the present review, we confer about clinical and preclinical studies exploring the association of obesity and related metabolic disorders with various gut microbiome profiles, and the effects of several dietary interventions on gut microbiome composition and the metabolome. It is well established that various nutritional interventions may serve as an efficient therapeutic approach to support weight loss in obese individuals, yet no agreement exists in regard to the most effective dietary protocol, both in the short and long term. However, metabolite profiling and the gut microbiota composition might represent an opportunity to methodically establish predictors for obesity control that are relatively simple to measure in comparison to traditional approaches, and it may also present a tool to determine the optimal nutritional intervention to ameliorate obesity in an individual. Nevertheless, a lack of adequately powered randomized trials impedes the application of observations to clinical practice.

Effect of Jiawei Tongqiao Huoxue decoction in basilar artery dolichoectasia mice through yes-associated protein/transcriptional Co-activator with PDZ-binding motif pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The Jiawei Tongqiao Huoxue decoction (JTHD), composed of Acorus calamus var. angustatus Besser, Paeonia lactiflora Pall., Conioselinum anthriscoides 'Chuanxiong', Prunus persica (L.) Batsch, Ziziphus jujuba Mill., Carthamus tinctorius L., Pueraria montana var. lobata (Willd.) Maesen & S.M.Almeida ex Sanjappa & Predeep, Zingiber officinale Roscoe, Leiurus quinquestriatus, and Moschus berezovskii Flerov, was developed based on Tongqiao Huoxue decoction in Wang Qingren's "Yilin Gaicuo" in the Qing Dynasty. It has the effect of improving not only the blood flow velocity of vertebral and basilar arteries but also the blood flow parameters and wall shear stress. Especially in recent years, the potential efficacy of traditional Chinese medicine (TCM) for the treatment of basilar artery dolichoectasia (BAD) has attracted great attention as there are still no specific remedies for this disease. However, its molecular mechanism has not been elucidated. To identify the potential mechanisms of JTHD will help to intervene BAD and provide a reference for its clinical application.

AIM OF THE STUDY

This study aims to establish a mouse model of BAD and explore the mechanism of JTHD regulating yes-associated protein/transcriptional co-activator with PDZ-binding motif (YAP/TAZ) pathway for attenuating BAD mice development.

MATERIALS AND METHODS

Sixty post-modeling C57/BL6 female mice were randomly divided into sham-operated, model, atorvastatin calcium tablet, low-dose JTHD, and high-dose JTHD groups. After 14 days of modeling, the pharmacological intervention was given for 2 months. Then, JTHD was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS). ELISA was utilized to detect the changes in vascular endothelial growth factor (VEGF) and lipoprotein a (Lp-a) in serum. EVG staining was conducted to observe the pathological changes of blood vessels. TUNEL method was employed to detect the apoptosis rate of vascular smooth muscle cells (VSMCs). Micro-CT and ImagePro Plus software were used to observe and calculate the tortuosity index, lengthening index, percentage increase in vessel diameter, and tortuosity of the basilar artery vessels in mice. Western blot analysis was performed to detect the expression levels of YAP and TAZ proteins in the vascular tissues of mice.

RESULTS

Many effective compounds such as choline, tryptophan, and leucine with anti-inflammation and vascular remodeling were identified in the Chinese medicine formula by LC-MS analysis. The serum levels of VEGF in the model mice decreased significantly while the levels of Lp-a increased obviously compared with those in the sham-operated group. The intima-media of the basilar artery wall showed severe disruption of the internal elastic layer, atrophy of the muscular layer, and hyaline changes of the connective tissue. Apoptosis of VSMCs added. Dilatation, elongation, and tortuosity of the basilar artery became notable, and tortuosity index, lengthening index, percentage increase in vessel diameter, and bending angle remarkably improved. The expression levels of YAP and TAZ protein in blood vessels elevated conspicuously (P < 0.05, P < 0.01). JTHD group markedly reduced the lengthening, bending angle, percentage increase in vessel diameter, and tortuosity index of basilar artery compared with the model group after 2 months of pharmacological intervention. The group also decreased the secretion of Lp-a and increased the content of VEGF. It inhibited the destruction of the internal elastic layer, muscular atrophy, and hyaline degeneration of connective tissue in basilar artery wall. The apoptosis of VSMCs was decreased, and the expression levels of YAP and TAZ proteins were abated (P < 0.05, P < 0.01).

CONCLUSIONS

The mechanism of inhibition of basilar artery elongation, dilation, and tortuosity by JTHD, which has various anti-BAD effective compound components, may be related to the reduction in VSMCs apoptosis and downregulation of YAP/TAZ pathway expression.

Insulin Resistance and Impaired Branched-Chain Amino Acid Metabolism in Alzheimer's Disease

The pathogenesis of Alzheimer's disease (AD) is complicated and involves multiple contributing factors. Mounting evidence supports the concept that AD is an age-related metabolic neurodegenerative disease mediated in part by brain insulin resistance, and sharing similar metabolic dysfunctions and brain pathological characteristics that occur in type 2 diabetes mellitus (T2DM) and other insulin resistance disorders. Brain insulin signal pathway is a major regulator of branched-chain amino acid (BCAA) metabolism. In the past several years, impaired BCAA metabolism has been described in several insulin resistant states such as obesity, T2DM and cardiovascular disease. Disrupted BCAA metabolism leading to elevation in circulating BCAAs and related metabolites is an early metabolic phenotype of insulin resistance and correlated with future onset of T2DM. Brain is a major site for BCAA metabolism. BCAAs play pivotal roles in normal brain function, especially in signal transduction, nitrogen homeostasis, and neurotransmitter cycling. Evidence from animal models and patients support the involvement of BCAA dysmetabolism in neurodegenerative diseases including Huntington's disease, Parkinson's disease, and maple syrup urine disease. More recently, growing studies have revealed altered BCAA metabolism in AD, but the relationship between them is poorly understood. This review is focused on the recent findings regarding BCAA metabolism and its role in AD. Moreover, we will explore how impaired BCAA metabolism influences brain function and participates in the pathogenesis of AD.

The effects of vitamin B6 on the nutritional support of BCAAs-enriched amino acids formula in rats with partial gastrectomy

BACKGROUND

Total parenteral nutrition with the formula of amino acids enriched branched-chain amino acids (BCAAs) could promote patients' recovery after gastrointestinal surgery. Previous studies reported that vitamin B6 could promote amino acid metabolism and enhance protein synthesis. The aim of this study was to determine if the addition of vitamin B6 to BCAAs-enriched formula can enhance postoperative nutritional status and intestinal function in rats undergoing partial gastrectomy, and the appropriate compatibility concentration of vitamin B6.

METHODS

Fifty-six male rats were randomly divided into seven groups (n = 8 per group): (I) Control, (II) BCAAs-enriched formula group (BCAA), (III) BCAA plus vitamin B6 (50 mg/L), (IV) BCAA plus vitamin B6 (100 mg/L), (V) BCAA plus vitamin B6 (200 mg/L), (VI) BCAA plus vitamin B6 (500 mg/L), and (VII) BCAA plus vitamin B6 (1000 mg/L). All animals were performed partial gastrectomy and placed a jugular vein catheter. During enteral nutrition, blood and urine samples were repeatedly collected. Gastrocnemius muscle and small intestine were also collected at the end of experiment.

RESULTS

The addition of vitamin B6 to BCAAs-enriched formula improved negative nitrogen balance after gastrectomy compared to the BCAAs-enriched formula group at POD1 (first postoperative day) and POD3 (third postoperative day), and 100 mg/L was an appropriate concentration of vitamin B6 to enhance the effects of BCAAs-enriched formula. The 3-methylhistidine/creatinine in BCAA plus vitamin B6 groups were significantly lower than that in the BCAA group at POD3. Moreover, BCAA plus vitamin B6 group significantly increased the cross-sectional area of the muscle fibers compared to the BCAA group. Transcriptome sequencing, GO and KEGG enhancement analysis also showed that BCAA plus vitamin B6 group showed muscle organ development and PI3K/AKT pathway enhancement compared to BCAA group. Moreover, AKT/mTOR/4EBP1 pathway was activated in BCAA plus vitamin B6 group. In addition, the results also showed that BCAA plus vitamin B6 decreased D-lactate, and exerted synergistic effects on intestinal morphology.

CONCLUSION

The addition of vitamin B6 to BCAAs-enriched formula could improve nitrogen balance, promote muscle protein synthesis through AKT/mTOR/4EBP1 pathway, and alleviate intestinal mucosa damage after partial gastrectomy in rats. Overall, the results from this pre-clinical study support the use of vitamin B6 as an ingredient to BCAAs-enriched formula, and 100 mg/L may be an optimal concentration for rats.

Leucine supplementation in maternal high-fat diet alleviated adiposity and glucose intolerance of adult mice offspring fed a postweaning high-fat diet

BACKGROUND

Combined maternal and postnatal high-fat (HF) diet intake predisposes offspring to metabolic dysregulation during adulthood. As the inhibitory effects of leucine consumption on obesity and metabolic disorders have been reported, the effects of maternal leucine supplementation on metabolic dysregulation in adult offspring were investigated.

METHODS

Female mice were exposed to a control (C) or HF diet, with or without leucine (L) supplementation (1.5%, w/v), 3 weeks before mating, during pregnancy, and during lactation (C, CL, HF, and HFL). Male offspring were exposed to an HF diet for 12 weeks after weaning (C/HF, CL/HF, HF/HF, and HFL/HF). Serum biochemical parameters were determined for both the dams and offspring. Oral glucose tolerance test and qRT-PCR analysis were used to investigate metabolic dysregulation in the offspring.

RESULTS

HFL dams exhibited higher relative adipose tissue weights than HF dams. Body weight, relative adipose tissue weight, and serum glucose levels were lower in the HFL/HF offspring than in the HF/HF offspring. Maternal leucine supplementation tended to alleviate glucose intolerance in the offspring of HF diet-fed dams. Additionally, mRNA levels of fibroblast growth factor 21 (FGF21), a hepatokine associated with glucose homeostasis, were higher in HFL/HF offspring than in HF/HF offspring and were negatively correlated with adiposity and serum glucose levels. The mRNA levels of genes encoding a FGF21 receptor complex, Fgf receptor 1 and klotho β, and its downstream targets, proliferator-activated receptor-γ co-activator 1α and sirtuin 1, were higher in adipose tissues of the HFL/HF offspring than in those of the HF/HF offspring. Serum lipid peroxide levels were lower in HFL dams than in HF dams and positively correlated with body and adipose tissue weights of offspring.

CONCLUSIONS

Leucine supplementation in HF diet-fed dams, but not in control diet-fed dams, resulted in an anti-obesity phenotype accompanied by glucose homeostasis in male offspring challenged with postnatal HF feeding. Activation of FGF21 signaling in the adipose tissue of offspring may be responsible for these beneficial effects of leucine.

Association of branched-chain amino acids with mortality-the Ludwigshafen Risk and Cardiovascular Health (LURIC) study

Branched-chain amino acids (BCAAs) are effectors of metabolic diseases, but their impact on mortality is largely unknown. We investigated the association of BCAA with risk factors and mortality in 2,236 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study using linear and Cox regression. Adiponectin, hemoglobin, C-peptide, hemoglobin A_1c, and homoarginine showed the strongest association with BCAA concentration (all p < 0.001). During a median follow-up of 10.5 years, 715 participants died, including 450 cardiovascular-related deaths. BCAA concentrations were inversely associated with the risk of all-cause and cardiovascular mortality (HR [95% CI] per 1-SD increase in log-BCAA: 0.75 [0.69-0.82] and 0.72 [0.65-0.80], respectively) after adjustment for potential confounders. BCAAs are directly associated with metabolic risk but inversely with mortality in persons with intermediate-to-high cardiovascular risk. Further studies are warranted to evaluate the diagnostic and therapeutic utility of BCAA in the context of cardiovascular diseases.

The Preventive Effect of Exercise and Oral Branched-Chain Amino Acid Supplementation on Obesity-Induced Brain Changes in Ldlr−/−.Leiden Mice

Exercise and dietary interventions are promising approaches to tackle obesity and its obesogenic effects on the brain. We investigated the impact of exercise and possible synergistic effects of exercise and branched-chain amino acids (BCAA) supplementation on the brain and behavior in high-fat-diet (HFD)-induced obese Ldlr−/−.Leiden mice. Baseline measurements were performed in chow-fed Ldlr−/−.Leiden mice to assess metabolic risk factors, cognition, and brain structure using magnetic resonance imaging. Thereafter, a subgroup was sacrificed, serving as a healthy reference. The remaining mice were fed an HFD and divided into three groups: (i) no exercise, (ii) exercise, or (iii) exercise and dietary BCAA. Mice were followed for 6 months and aforementioned tests were repeated. We found that exercise alone changed cerebral blood flow, attenuated white matter loss, and reduced neuroinflammation compared to non-exercising HFD-fed mice. Contrarily, no favorable effects of exercise on the brain were found in combination with BCAA, and neuroinflammation was increased. However, cognition was slightly improved in exercising mice on BCAA. Moreover, BCAA and exercise increased the percentage of epididymal white adipose tissue and muscle weight, decreased body weight and fasting insulin levels, improved the circadian rhythm, and transiently improved grip strength. In conclusion, BCAA should be supplemented with caution, although beneficial effects on metabolism, behavior, and cognition were observed.

Protein Intake Is Associated with Blood Pressure and Cholesterol Levels in Italian Older Adults: A Cross-Sectional Study

The present study was conducted to test the association between protein intake and blood pressure, glucose levels, and blood cholesterol in a large sample of Italian older adults. Longevity Check-up 7+ (Lookup 7+) is an ongoing project that started in June 2015. The project is conducted in unconventional settings (e.g., exhibitions, malls, health promotion campaigns) across Italy with the aim of fostering adoption of healthy lifestyles in the general population. For the present study, participants were eligible if they were 65+ years and provided written informed consent. Systolic (SBP) and diastolic blood pressure (DBP), and blood glucose and cholesterol levels were assessed. Protein intake was estimated using a 12-item food frequency questionnaire. Three-thousand four-hundred and four older adults were included in the study. The results of the linear regression showed an inverse association between protein intake (as a continuous variable) and DBP, and a positive correlation with blood cholesterol levels. The findings of the present study indicate that a high intake of protein was negatively associated with DBP and positively associated with total blood cholesterol levels in a large cohort of Italian older adults, after adjustment for numerous covariates.

Short-Term Decreasing and Increasing Dietary BCAA Have Similar, but Not Identical Effects on Lipid and Glucose Metabolism in Lean Mice

Branched-chain amino acids (BCAA) showed multiple functions in glycolipid metabolism and protein synthesis. However, the impacts on the metabolic health of low or high dietary BCAA remain controversial due to the various experimental conditions. Gradient levels of BCAA were supplemented in lean mice for four weeks: 0BCAA (without BCAA), 1/2BCAA (half BCAA), 1BCAA (regular BCAA), and 2BCAA (double BCAA). The results showed that the diet without BCAA caused energy metabolic disorders, immune defects, weight loss, hyperinsulinemia, and hyperleptinemia. 1/2BCAA and 2BCAA diets reduced body fat percentage, but 1/2 BCAA also decreased muscle mass. 1/2BCAA and 2BCAA groups improved lipid and glucose metabolism by affecting metabolic genes. Meanwhile, significant differences between low and high dietary BCAA were observed. The results of this study provide evidence and reference for the controversy about dietary BCAA levels, which indicates that the main difference between low and high BCAA dietary levels may present in the longer term.

Organic vegetable juice supplement alleviates hyperlipidemia in diet-induced obese mice and modulates microbial community in continuous colon simulation system

In this study, we investigated the effects of organic vegetable juice (OVJ) supplementation on modulating the microbial community, and how its consumption ameliorated blood-lipid profiles in diet-induced obese mice. Here, we studied the alleviating effect of hyperlipidemia via animal experiments using diet-induced obese mice and analyzed the effect of OVJ on the microbial community in continuous colon simulation system. OVJ consumption did not have a significant effect on weight loss but helped reduce the weight of the epididymis fat tissue and adipocytes. Additionally, blood-lipid profiles, such as triglyceride, high-density lipoprotein, and glucose, were improved in the OVJ-fed group. Expression levels of genes related to lipid synthesis, including SREBP-1, PPARγ, C/EBPα, and FAS, were significantly decreased. In addition, OVJ treatment significantly reduced inflammatory cytokines and oxidative stress. OVJ supplement influenced intestinal bacterial composition from phylum to genus level, including decreased Proteobacteria in the ascending colon in the phylum. At the family level, Akkermansia, which are associated with obesity, were significantly augmented in the transverse colon and descending colon compared to the control juice group. In addition, treatment with OVJ affected predicted lipid-metabolism-function genes related to lipid synthesis. These results suggest that OVJ supplementation may modulate gut microbial community and reduce the potential symptom of hyperlipidemia in diet-obese mice.

Hepatic-Modulatory Effects of Chicken Liver Hydrolysate-Based Supplement on Autophagy Regulation against Liver Fibrogenesis

Chicken-liver hydrolysates (CLHs) have been characterized as performing several biofunctions by our team. This study aimed to investigate if a CLH-based supplement (GBHP01^TM) can ameliorate liver fibrogenesis induced by thioacetamide (TAA) treatment. Our results showed that the TAA treatment caused lower body weight gains and enlarged livers, as well as higher serum ALT, AST, and ALP levels (p < 0.05). This liver inflammatory and fibrotic evidence was ameliorated (p < 0.05) by supplementing with GBHP01^TM; this partially resulted from its antioxidant abilities, including decreased TBARS values but increased TEAC levels, reduced GSH contents and catalase/GPx activities in the livers of TAA-treated rats (p < 0.05). Additionally, fewer nodules were observed in the appearance of the livers of TAA-treated rats after supplementing with GBHP01^TM. Similarly, supplementing GBHP01^TM decreased fibrotic scars and the fibrotic score in the livers of TAA-treated rats (p < 0.05). Moreover, the increased hepatic IL-6, IL-1β, and TNF-α levels after TAA treatment were also alleviated by supplementing with GBHP01^TM (p < 0.05). Meanwhile, GBHP01^TM could decrease the ratio of LC3B II/LC3B I, but upregulated P62 and Rab7 in the livers of TAA-treated rats (p < 0.05). Taking these results together, the CLH-based supplement (GBHP01^TM) can be characterized as a natural agent against liver fibrogenesis.

Effect of increasing valine level in the diet on performance, egg quality, and serum components in laying quails

This research was conducted to determine the effect of increasing dietary valine level on performance parameters, egg quality criteria, and blood and serum components. In the study, 120 female Japanese quails at the age of 10 weeks (241.4 ± 8.6 g) did randomly allocate to six experimental groups contained five subgroups. Treatment diets were prepared to contain 0.93% (control), 1.00%, 1.10%, 1.20%, 1.30%, or 1.40% valine. The egg mass decreased linearly with the increasing level of valine in the diet, while egg weight decreased in both linear and quadratic manner (P < 0.05). Increased levels of dietary valine increased eggshell breaking strength in cubic manner (P < 0.05). The administration of the valine to the diet caused a linear decrease in the albumin index and Haugh unit (P < 0.05). Other egg quality parameters were not affected (P > 0.05). Serum glucose and triglyceride concentrations of laying quails were reduced by the increasing dietary valine levels; the effect on serum glucose was linear, while both linear and quadratic effects were significant on triglyceride concentration (P < 0.05). White blood cell, lymphocyte, and neutrophil counts increased with the increasing dietary levels of valine (P < 0.05). Both linear and quadratic effects were significant on white blood cells and lymphocytes, while the effect on neutrophil counts was linear. However, erythrocyte and haematocrit (P < 0.05) decreased quadratically with increment in the dietary levels of valine. In conclusion, the increased valine levels in the diet adversely affected the egg weight, egg mass, and Haugh unit. but it reduced the serum triglyceride and glucose. Results may suggest that dietary valine at 0.93% level is sufficient for egg production and egg quality in laying quails, but positive effects of increased dietary valine levels on white blood cells may worth to investigate further.

Potential Therapies Targeting the Metabolic Reprogramming of Diabetes-Associated Breast Cancer

In recent years, diabetes-associated breast cancer has become a significant clinical challenge. Diabetes is not only a risk factor for breast cancer but also worsens its prognosis. Patients with diabetes usually show hyperglycemia and hyperinsulinemia, which are accompanied by different glucose, protein, and lipid metabolism disorders. Metabolic abnormalities observed in diabetes can induce the occurrence and development of breast cancer. The changes in substrate availability and hormone environment not only create a favorable metabolic environment for tumorigenesis but also induce metabolic reprogramming events required for breast cancer cell transformation. Metabolic reprogramming is the basis for the development, swift proliferation, and survival of cancer cells. Metabolism must also be reprogrammed to support the energy requirements of the biosynthetic processes in cancer cells. In addition, metabolic reprogramming is essential to enable cancer cells to overcome apoptosis signals and promote invasion and metastasis. This review aims to describe the major metabolic changes in diabetes and outline how cancer cells can use cellular metabolic changes to drive abnormal growth and proliferation. We will specifically examine the mechanism of metabolic reprogramming by which diabetes may promote the development of breast cancer, focusing on the role of glucose metabolism, amino acid metabolism, and lipid metabolism in this process and potential therapeutic targets. Although diabetes-associated breast cancer has always been a common health problem, research focused on finding treatments suitable for the specific needs of patients with concurrent conditions is still limited. Most studies are still currently in the pre-clinical stage and mainly focus on reprogramming the glucose metabolism. More research targeting the amino acid and lipid metabolism is needed.

Branched-Chain Amino Acids and Insulin Resistance, from Protein Supply to Diet-Induced Obesity

For more than a decade, there has been a wide debate about the branched-chain amino acids (BCAA) leucine, valine, and isoleucine, with, on the one hand, the supporters of their anabolic effects and, on the other hand, those who suspect them of promoting insulin resistance. Indeed, the role of leucine in the postprandial activation of protein synthesis has been clearly established, even though supplementation studies aimed at taking advantage of this property are rather disappointing. Furthermore, there is ample evidence of an association between the elevation of their plasma concentrations and insulin resistance or the risk of developing type 2 diabetes, although there are many confounding factors, starting with the level of animal protein consumption. After a summary of their metabolism and anabolic properties, we analyze in this review the factors likely to increase the plasma concentrations of BCAAs, including insulin-resistance. After an analysis of supplementation or restriction studies in search of a direct role of BCAAs in insulin resistance, we discuss an indirect role through some of their metabolites: branched-chain keto acids, C3 and C5 acylcarnitines, and hydroxyisobutyrate. Overall, given the importance of insulin in the metabolism of these amino acids, it is very likely that small alterations in insulin sensitivity are responsible for a reduction in their catabolism long before the onset of impaired glucose tolerance.

The Potential Role of R4 Regulators of G Protein Signaling (RGS) Proteins in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a complex and heterogeneous disease that primarily results from impaired insulin secretion or insulin resistance (IR). G protein-coupled receptors (GPCRs) are proposed as therapeutic targets for T2DM. GPCRs transduce signals via the Gα protein, playing an integral role in insulin secretion and IR. The regulators of G protein signaling (RGS) family proteins can bind to Gα proteins and function as GTPase-activating proteins (GAP) to accelerate GTP hydrolysis, thereby terminating Gα protein signaling. Thus, RGS proteins determine the size and duration of cellular responses to GPCR stimulation. RGSs are becoming popular targeting sites for modulating the signaling of GPCRs and related diseases. The R4 subfamily is the largest RGS family. This review will summarize the research progress on the mechanisms of R4 RGS subfamily proteins in insulin secretion and insulin resistance and analyze their potential value in the treatment of T2DM.

Higher Intake of Total Dietary Essential Amino Acids Is Associated with a Lower Prevalence of Metabolic Syndrome among Korean Adults

We hypothesized that a well-balanced intake of total essential amino acids (EAAs) may be associated with lower prevalence of metabolic syndrome among Korean adults. This population-based cross-sectional study included 25,787 participants aged ≥30 years from the 2008-2019 Korea National Health and Nutrition Examination Survey. Dietary information was obtained from 24 h recall data. Demographic and lifestyle factors were assessed using self-administered questionnaires, and metabolic biomarkers were obtained from a health examination. Total essential amino acid score (EAAS) was calculated to determine whether essential amino acid (EAA) intake meets the recommended nutrient intake (RNI). Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. After adjusting for multiple confounding factors, participants with higher EAAS had a significantly lower prevalence of high blood pressure (OR: 0.86, 95% CI: 0.75-0.98), hypertriglyceridemia (OR: 0.86, 95% CI: 0.76-0.98), and Metabolic syndrome (MetS) (OR: 0.86, 95% CI: 0.74-0.996). Spline regression analysis confirmed linearity of the association between total EAAS and MetS. EAA intake and MetS are associated with an inverse dose-response relationship in which metabolic disease may be prevented when the overall EAA intake meets the RNI.

Association of nut consumption with CVD risk factors in young to middle-aged adults: The Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND AND AIMS

Few studies have examined long-term associations of walnut, other nut, and no nut consumption with cardiovascular disease (CVD) risk factors. Results from prospective studies with long-term follow-up can provide further evidence for dietary guideline messaging to consume nuts. Therefore, we examined the associations of walnut, other nut, and no nut consumption with diet quality and CVD risk factors over 30 years of follow-up.

METHODS AND RESULTS

Data were analyzed from 3092 young adults enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Dietary intake, including walnuts and other nuts, was assessed 3 times over 20 years. CVD risk factors were measured at multiple exams. General linear regression evaluated the associations of walnut, other nut, and no nut consumption with CVD risk factors over 30 years (Y30) of follow-up. The 20-year cumulative mean intake of walnuts (0.74 oz/d), other nuts (1.6 oz/d), or no nut consumption was differentially associated with HEI-2015 and CVD risk factors by Y30. Generally, walnut consumers had significantly higher HEI-2015, lower body mass index, waist circumference, blood pressure, and triglyceride concentration, and gained less weight since baseline than other nut consumers (p ≤ 0.05 for all). Further, walnut consumers had lower fasting blood glucose than no nut consumers (p ≤ 0.05).

CONCLUSION

Study findings that walnut and other nut consumption was associated with better CVD risk factors and diet quality aligns with the 2020-2025 US. Dietary Guidelines for Americans recommendation to consume nuts, such as walnuts, within the context of a healthy diet.

Leucine Supplementation in Middle-Aged Male Mice Improved Aging-Induced Vascular Remodeling and Dysfunction via Activating the Sirt1-Foxo1 Axis

Vascular aging is associated with metabolic remodeling, and most studies focused on fatty acid and glucose metabolism. Based on our metabolomic data, leucine was significantly reduced in the aortas of aged mice. Whether leucine supplementation can reverse aging-induced vascular remodeling remains unknown. To investigate the effectiveness of leucine, male mice at 15 or 18 months were supplemented with leucine (1.5%) for 3 months. All the aged mice, with or without leucine, were sacrificed at 21 months. Blood pressure and vascular relaxation were measured. H&E, Masson’s trichrome, and Elastica van Gieson staining were used to assess aortic morphology. Vascular inflammation, reactive oxidative stress (ROS), and vascular smooth muscle cell (VSMC) phenotype were also measured in mouse aortas. Compared with the 21-month-old mice without leucine, leucine supplementation from 15 months significantly improved vascular relaxation, maintained the contractile phenotype of VSMCs, and repressed vascular inflammation and ROS levels. These benefits were not observed in the mice supplemented with leucine starting from 18 months, which was likely due to the reduction in leucine transporters Slc3a2 or Slc7a5 at 18 months. Furthermore, we found benefits from leucine via activating the Sirt1-induced Foxo1 deacetylation. Our findings indicated that leucine supplementation in middle-aged mice improved aging-induced vascular remodeling and dysfunction.