Branched-chain amino acids promote endothelial dysfunction through increased reactive oxygen species generation and inflammation

Metabolomics of Arterial Stiffness

Arterial stiffness (AS) is one of the earliest detectable signs of structural and functional alterations of the vessel wall and an independent predictor of cardiovascular events and death. The emerging field of metabolomics can be utilized to detect a wide spectrum of intermediates and products of metabolism in body fluids that can be involved in the pathogenesis of AS. Research over the past decade has reinforced this idea by linking AS to circulating acylcarnitines, glycerophospholipids, sphingolipids, and amino acids, among other metabolite species. Some of these metabolites influence AS through traditional cardiovascular risk factors (e.g., high blood pressure, high blood cholesterol, diabetes, smoking), while others seem to act independently through both known and unknown pathophysiological mechanisms. We propose the term 'arteriometabolomics' to indicate the research that applies metabolomics methods to study AS. The 'arteriometabolomics' approach has the potential to allow more personalized cardiovascular risk stratification, disease monitoring, and treatment selection. One of its major goals is to uncover the causal metabolic pathways of AS. Such pathways could represent valuable treatment targets in vascular ageing.

The Role of Amino Acids in Endothelial Biology and Function

The vascular endothelium acts as an important component of the vascular system. It is a barrier between the blood and vessel wall. It plays an important role in regulating blood vessel tone, permeability, angiogenesis, and platelet functions. Several studies have shown that amino acids (AA) are key regulators in maintaining vascular homeostasis by modulating endothelial cell (EC) proliferation, migration, survival, and function. This review summarizes the metabolic and signaling pathways of AAs in ECs and discusses the importance of AA homeostasis in the functioning of ECs and vascular homeostasis. It also discusses the challenges in understanding the role of AA in the development of cardiovascular pathophysiology and possible directions for future research.

Metabolomic Profiling of Brain Protective Effect of Edaravone on Cerebral Ischemia-Reperfusion Injury in Mice

Edaravone (EDA) injection has been extensively applied in clinics for treating stroke. Nevertheless, the metabolite signatures and underlying mechanisms associated with EDA remain unclear, which deserve further elucidation for improving the accurate usage of EDA. Ischemia stroke was simulated by intraluminal occlusion of the right middle cerebral artery for 1 h, followed by reperfusion for 24 h in mice. Brain infarct size, neurological deficits, and lactate dehydrogenase (LDH) levels were improved by EDA. Significantly differential metabolites were screened with untargeted metabolomics by cross-comparisons with pre- and posttreatment of EDA under cerebral ischemia/reperfusion (I/R) injury. The possibly involved pathways, such as valine, leucine, and isoleucine biosynthesis, and phenylalanine, taurine, and hypotaurine metabolisms, were enriched with differential metabolites and relevant regulatory enzymes, respectively. The network of differential metabolites was constructed for the integral exhibition of metabolic characteristics. Targeted analysis of taurine, an important metabolic marker, was performed for further validation. The level of taurine decreased in the MCAO/R group and increased in the EDA group. The inhibition of EDA on cerebral endothelial cell apoptosis was confirmed by TdT-mediated dUTP nick-end labeling (TUNEL) stain. Cysteine sulfinic acid decarboxylase (CSAD), the rate-limiting enzyme of taurine generation, significantly increased along with inhibiting endothelial cell apoptosis after treatment of EDA. Thus, CSAD, as the possible new therapeutic target of EDA, was selected and validated by Western blot and immunofluorescence. Together, this study provided the metabolite signatures and identified CSAD as an unrecognized therapeutic intervention for EDA in the treatment of ischemic stroke via inhibiting brain endothelial cell apoptosis.

Lipid Behavior in Metabolic Syndrome Pathophysiology

Undeniably, lipid plays an extremely important role in the homeostasis balance since lipid contributes to the regulation of the metabolic processes. The metabolic syndrome pathogenesis is multi-pathway that composes neurohormonal disorders, endothelial cell dysfunction, metabolic disturbance, genetic predisposition, in addition to gut commensal microbiota. The heterogenicity of the possible mechanisms gives the metabolic syndrome its complexity and limitation of therapeutic accesses. The main pathological link is that lipid contributes to the emergence of metabolic syndrome via central obesity and visceral obesity that consequently lead to oxidative stress and chronic inflammatory response promotion. Physiologically, a balance is kept between the adiponectin and adipokines levels to maintain the lipid level in the organism. Clinically, extremely important to define the borders of the lipid level in which the pathogenesis of the metabolic syndrome is reversible, otherwise it will be accompanied by irreversible complications and sequelae of the metabolic syndrome (cardiovascular, insulin resistance). The present paper is dedicated to providing novel insights into the role of lipid in the development of metabolic syndrome; hence dyslipidemia is the initiator of insulin resistance syndrome (metabolic syndrome).

High L-Valine Concentrations Associate with Increased Oxidative Stress and Newly-Diagnosed Type 2 Diabetes Mellitus: A Cross-Sectional Study

OBJECTIVE

Branched-chain amino acids (BCAAs) are essential AAs which are widely used as antioxidants in patients with liver and kidney dysfunction. However, BCAAs are strongly correlated with insulin resistance (IR) and diabetes. This study aimed to evaluate the relationship among BCAAs, oxidative stress, and type 2 diabetes mellitus (T2DM) in a Chinese population.

METHODS

Anthropometric and biochemical examinations were performed in 816 individuals who participated in the Huai'an Diabetes Prevention Program. Serum BCAAs concentrations were measured by hydrophilic interaction chromatography-tandem mass spectrometric method. Oxidative stress was evaluated by malondialdehyde (MDA) as an index of lipid peroxidation and the superoxide dismutase (SOD) activity.

RESULTS

A total of 816 participants were divided into three groups: normal glucose metabolism (NGM), prediabetes, and newly-diagnosed diabetes mellitus (NDM). Subjects in NDM group show higher MDA and lower SOD levels than subjects in other groups. L-Val levels positively correlated with MDA levels and negatively with SOD in NDM groups. After adjusting for T2DM risk factors, high L-Val levels were significantly associated with higher BMI, WC, FPG, increased LnTG and decreased HDL-C. L-Val was also independently associated with NDM (OR 1.06, 95% CI 1.02-1.10; P = 0.005). Furthermore, the odds ratios for NDM among participants with high L-Val (≥35.25μg/mL) levels showed a 2.25-fold (95% CI 1.11-4.57; P = 0.024) increase compared to participants with low L-Val (<27.26 μg/mL) levels after adjusting for MDA and confounding factors.

CONCLUSION

High serum L-Val levels are independently associated with oxidative stress, thus promoting IR and NDM. Further study should be done to clarify the mechanism.

Metabolomic characteristics of hand-foot-mouth disease facilitate discovery and diagnosis of pathogeny

BACKGROUND

Hand-foot-mouth disease (HFMD) is a significant public health concern, especially in Asia-Pacific countries. Its diagnosis mainly depends on clinical symptoms. It is easy to miss the source of infection and best treatment period. This research aims to provide a tool for its early clinical diagnosis and for predicting the possibility of complications.

METHODS

The serum samples of 39 HFMD children and 36 healthy children were collected for clinical testing and ¹ H-NMR spectroscopy. Metabolomic analyses were performed to obtain the metabolic differences between the HFMD and healthy children and to speculate on the pathogenesis of HFMD.

RESULTS

Thirty-nine children were divided into severe cases and mild cases. Severe cases demonstrated more obvious inflammatory responses, but no metabolic difference was observed between the severe and mild cases. The metabolic differences between HFMD and healthy children were noticeable. Ten differential metabolites were screened out as the potential biomarkers for HFMD, and seven disturbed metabolic pathways responsible for HFMD were affected by inflammation, impaired intestinal absorptive function, and immune response.

CONCLUSIONS

Our results will provide a complementary tool for the early diagnosis of HFMD and potential ideas for later treatment.

Validation of a Short Food Frequency Questionnaire to Measure Dietary Intake of a Selection of Micronutrients in Oncology Patients Undergoing Systemic Therapy

Dietary intake, specifically consumption of anti-inflammatory micronutrients, can play a role in both cancer initiation as well as the treatment-related outcomes experienced by patients receiving systemic cancer therapy. Increasing research is being conducted to determine whether micronutrient supplementation can aid in altering the tumor microenvironment (TME), reducing inflammatory side effects and immune-related adverse events (irAEs). However, further research pertaining to the adequacy of dietary micronutrient intake is indicated in the oncology cohort. Currently, no tool measuring dietary intakes of various micronutrients exists in the oncology population. In this study, a 21-item food frequency questionnaire (FFQ) measuring intakes of 14 different micronutrients was validated using diet history as the reference method in 112 oncology patients. Bland Altman plot and Passing Bablok regression analysis were conducted to determine agreement between the two methods. The results showed adequate agreement between FFQ and diet history for 12 nutrients including copper, iron, vitamins A, E, and D, alpha linolenic acid (ALA), long-chain omega 3 fatty acids (LC n3-FA), arginine, glutamic acid, isoleucine, leucine, and valine. This 21-item FFQ, which takes an average of 10 min to complete, can be utilized as a quick screening tool to determine adequacy for 12 different micronutrients in place of a diet history.

Metabolomics and pharmacodynamic analysis reveal the therapeutic role of Prunella vulgaris oil on intrauterine adhesion rats

Metabolomics is applied to explore the curative effect of complex systems, such as Chinese medicine. Intrauterine adhesion (IUA) harms the reproductive system and affects fertility, and hence is a significant public health concern. Prunella vulgaris oil (PVO) protects the reproductive system and exerts anti-inflammatory effects, but its effect on IUA and the underlying mechanism is unclear. In this study, we established a serum metabolomics method based on GC-TOF-MS to evaluate the mechanism of PVO in the IUA rat model established by mechanical injury and infection. Animal experiments showed that PVO improves the inflammatory response in the uterus of IUA model rats and reduces the content of inflammatory factors to improve the microenvironment of the reproductive system. It also regulates the expression of TGF-β1 and Smad-related mRNA and protein to inhibit fibrosis. Metabolomics indicated a significant abnormality in serum metabolism in IUA rats, and a total of 51 differential markers were screened and identified. After PVO treatment, these metabolic abnormalities improved significantly. The metabolic pathway analysis revealed that PVO affects glyoxylate and dicarboxylate metabolism, and β-alanine metabolism pathways. This study showed that PVO significantly improves inflammation and fibrosis in IUA rats combined with the pharmacological results. The primary mechanism is related to regulating the metabolism of amino acids and their derivatives to balance the associated disorders and control energy metabolism.

A metabolomic index based on lipoprotein subfractions and branched chain amino acids is associated with incident hypertension

OBJECTIVE

The present study aims to evaluate the performance of the Diabetes Risk Index (DRI), a metabolomic index based on lipoprotein particles and branched chain amino acids, on the incidence of newly developed hypertension in a large community dwelling cohort.

METHODS

The DRI was calculated by combining 6 lipoprotein parameters [sizes of very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL), concentrations of large VLDL, small LDL, and large HDL particles], and the concentrations of valine and leucine. DRI scores were estimated in 4169 participants from the PREVEND prospective cohort. Cox proportional hazards regression was used to evaluate the association of DRI scores with incident hypertension.

RESULTS

During a median follow-up of 8.6 years, 924 new hypertension cases were ascertained. In analyses adjusted for age and sex, there was a significant association between DRI and incident hypertension with a hazard ratio (HR) per 1 SD increase of 1.45 (95% CI 1.36,1.54; p < 0.001). After additional adjustment for traditional risk factors, the HR remained significant (HR_adj 1.21, 95% CI 1.10, 1.33, p <0.001). Likewise, subjects in the top quartile of DRI presented with a higher risk of hypertension (HR_adj 1.64, 95% CI 1.28, 2.10, p <0.001). Furthermore, the net reclassification improvement assessment improved after the addition of DRI to a traditional risk model (p <0.001), allowing proper reclassification of 34% of the participants.

CONCLUSION

Higher DRI scores were associated with an increased risk of incident hypertension. Such association was independent of traditional clinical risk factors for hypertension.

The use of BCAA to decrease delayed-onset muscle soreness after a single bout of exercise: a systematic review and meta-analysis

Branched-chain amino acids (BCAA) are used as a recovery method after exercise-induced muscle damage (EIMD). Although data suggest that BCAA may alleviate the delayed-onset muscle soreness (DOMS) evoked by EIMD, there is no consensus about the most effective supplementation protocol. To investigate the effects of BCAA on DOMS after a single exercise session that caused EIMD, a systematic review and meta-analysis were conducted on the effectiveness of BCAA supplementation to reduce DOMS symptoms in healthy subjects after a single session of EIMD. Randomized clinical trials (RCT) were searched in Medline, Cochrane Library, Science Direct, SciELO, LILACS, SciVerse Scopus, Springer Link journals, Wiley Online Library, and Scholar Google, until May 2021. Ten RCTs were included in the systematic review and nine in the meta-analysis. Seven studies demonstrated that BCAA reduced DOMS after 24 to 72 h. BCAA doses of up to 255 mg/kg/day, or in trained subjects, for mild to moderate EIMD, could blunt DOMS symptoms. However, high variability between studies due to training status, different doses, time of treatment, and severity of EIMD do not allow us to conclude whether BCAA supplementation is efficient in untrained subjects, applied acutely or during a period of pre to post days of EIMD, and at higher doses (> 255 mg/kg/day). The overall effects of BCAA on DOMS after a single session of exercise were considered useful for improving muscle recovery by reducing DOMS in trained subjects, at low doses, in mild to moderate EIMD, and should not be administered only after the EIMD protocol.

Functional Metabolic Mapping Reveals Highly Active Branched-Chain Amino Acid Metabolism in Human Astrocytes, Which Is Impaired in iPSC-Derived Astrocytes in Alzheimer's Disease

The branched-chain amino acids (BCAAs) leucine, isoleucine, and valine are important nitrogen donors for synthesis of glutamate, the main excitatory neurotransmitter in the brain. The glutamate carbon skeleton originates from the tricarboxylic acid (TCA) cycle intermediate α-ketoglutarate, while the amino group is derived from nitrogen donors such as the BCAAs. Disturbances in neurotransmitter homeostasis, mainly of glutamate, are strongly implicated in the pathophysiology of Alzheimer's disease (AD). The divergent BCAA metabolism in different cell types of the human brain is poorly understood, and so is the involvement of astrocytic and neuronal BCAA metabolism in AD. The goal of this study is to provide the first functional characterization of BCAA metabolism in human brain tissue and to investigate BCAA metabolism in AD pathophysiology using astrocytes and neurons derived from human-induced pluripotent stem cells (hiPSCs). Mapping of BCAA metabolism was performed using mass spectrometry and enriched [¹⁵N] and [¹³C] isotopes of leucine, isoleucine, and valine in acutely isolated slices of surgically resected cerebral cortical tissue from human brain and in hiPSC-derived brain cells carrying mutations in either amyloid precursor protein (APP) or presenilin-1 (PSEN-1). We revealed that both human astrocytes of acutely isolated cerebral cortical slices and hiPSC-derived astrocytes were capable of oxidatively metabolizing the carbon skeleton of BCAAs, particularly to support glutamine synthesis. Interestingly, hiPSC-derived astrocytes with APP and PSEN-1 mutations exhibited decreased amino acid synthesis of glutamate, glutamine, and aspartate derived from leucine metabolism. These results clearly demonstrate that there is an active BCAA metabolism in human astrocytes, and that leucine metabolism is selectively impaired in astrocytes derived from the hiPSC models of AD. This impairment in astrocytic BCAA metabolism may contribute to neurotransmitter and energetic imbalances in the AD brain.

Combined Untargeted and Targeted Metabolomics Approaches Reveal Urinary Changes of Amino Acids and Energy Metabolism in Canine Babesiosis With Different Levels of Kidney Function

Canine babesiosis is a tick-borne disease with a worldwide distribution, caused by the haemoprotozoan parasites of the genus Babesia. One of the most prevalent complication is acute kidney injury, and an early diagnosis of altered kidney function remains a challenge for veterinary practice. The aim of this study was to assess the urine metabolic profile from dogs with babesiosis and different degree of kidney function using untargeted and targeted MS-based metabolomics approaches. In this study, 22 dogs naturally infected with Babesia canis and 12 healthy dogs were included. Untargeted metabolomics approach identified 601 features with a differential abundance between the healthy group and groups of dogs with babesiosis and different level of kidney function, with 27 of them identified as a match to known standards; while targeted approach identified 17 metabolites with significantly different concentrations between the groups. A pattern of significantly altered metabolites referring to the inflammatory host response, oxidative stress, and energy metabolism modulation in babesiosis was presented. Our findings have demonstrated that kidney dysfunction accompanying canine babesiosis was associated with changes in amino acid metabolism, energy metabolism, fatty acid metabolism, and biochemical pathways such as urea cycle and ammonia detoxication. These findings will enable the inclusion of urinary markers for the detection and monitoring of renal damage in babesiosis, as well as in other similar diseases.

Tryptophan: From Diet to Cardiovascular Diseases

Cardiovascular disease (CVD) is one of the major causes of mortality worldwide. Inflammation is the underlying common mechanism involved in CVD. It has been recently related to amino acid metabolism, which acts as a critical regulator of innate and adaptive immune responses. Among different metabolites that have emerged as important regulators of immune and inflammatory responses, tryptophan (Trp) metabolites have been shown to play a pivotal role in CVD. Here, we provide an overview of the fundamental aspects of Trp metabolism and the interplay between the dysregulation of the main actors involved in Trp metabolism such as indoleamine 2, 3-dioxygenase 1 (IDO) and CVD, including atherosclerosis and myocardial infarction. IDO has a prominent and complex role. Its activity, impacting on several biological pathways, complicates our understanding of its function, particularly in CVD, where it is still under debate. The discrepancy of the observed IDO effects could be potentially explained by its specific cell and tissue contribution, encouraging further investigations regarding the role of this enzyme. Thus, improving our understanding of the function of Trp as well as its derived metabolites will help to move one step closer towards tailored therapies aiming to treat CVD.

β-Lactolin Reduces Age-Related Inflammation and Cognitive Decline

With the rapid increase in aging populations worldwide, there has been an increase in demand for preventive and therapeutic measures for age-related cognitive decline and dementia. Epidemiological studies show that consumption of dairy products reduces the risk for cognitive decline and dementia in the elderly. We have previously demonstrated in randomized trials that the consumption of β-lactolin, a whey-derived Gly-Thr-Trp-Tyr lactotetrapeptide, improves cognitive function in older adults. Orally administered β-lactolin is delivered to the brain and inhibits monoamine oxidase, resulting in alleviation of memory impairment. However, there is currently no evidence of the effects of long-term β-lactolin intake on aging. Here, we found that the discrimination index in the novel object recognition test for object recognition memory was reduced in mice aged 20 months compared with that in young mice, indicating that age-related cognitive decline was induced in the aged mice; in aged mice fed β-lactolin for 3 months, memory impairment was subsequently alleviated. In aged mice, impairment of light/dark activity cycles was found to be induced, which was subsequently alleviated by β-lactolin consumption. Additionally, the number of activated microglia in the hippocampus and cortex and the production of cytokines (tumor necrosis factor-α, macrophage inflammatory protein-1α, and macrophage chemoattractant protein-1) were increased in aged mice compared with those in young mice but were reduced in aged mice fed β-lactolin. The age-related hippocampal atrophy was improved in aged mice fed β-lactolin. Cytochrome c levels in the hippocampus and cortex were increased in aged mice compared with those in young mice but were also reduced by β-lactolin consumption. These results suggest that β-lactolin consumption prevents neural inflammation and alleviates aging-related cognitive decline.

Serum metabolites of hypertension among Chinese adolescents aged 12-17 years

The regulatory mechanisms of hypertension in youth are incompletely understood. We aimed to identify potential serum metabolic alterations associated with hypertension in adolescents. A 1:1 age- and sex-matched case-control study including 30 hypertensive adolescents aged 12-17 years and 30 normotensive adolescents for the training set and 14 hypertensive adolescents and 14 normotensive adolescents for the test set was performed, which came from one cross-sectional study in Ningxia, China. Hypertension was defined based on blood pressure (BP) values measured on three different occasions according to the BP reference of Chinese children and adolescents. Untargeted ultra-high-performance liquid tandem chromatography quadrupole time of flight mass spectrometry was used to identify differential metabolites between hypertensive and normotensive adolescents. A total of 77 metabolites in positive mode and 101 in negative mode were identified (VIP > 1.0 and P < 0.05). After adjustment for the false discovery rate, 4 differential metabolites in positive mode and 10 in negative mode were found (Q value < 0.05). The logistic regression model adjusted for body mass index and lipid profile selected four significant metabolites (4-hydroxybutanoic acid, L-serine, acetone, and pterostilbene). The main metabolic pathways of amino acid metabolism, pantothenate and CoA biosynthesis, glyoxylate and dicarboxylate metabolism, fructose and mannose metabolism, and linoleic acid metabolism may contribute to the development of hypertension in Chinese adolescents. Based on the receiver operating characteristic plot, 4-hydroxybutanoic acid, L-serine, acetone, and pterostilbene may preliminarily help distinguish hypertension from normal BP in adolescents, with AUC values of 0.857 in the training set and 0.934 in the test set. The identified metabolites and pathways may foster a better understanding of hypertension pathogenesis in Chinese adolescents.

Gut microbiota as a target for prevention and treatment of type 2 diabetes: Mechanisms and dietary natural products

Type 2 diabetes mellitus (T2DM) is among the most remarkable public health concerns globally. Accumulating research evidence documents that alteration of gut microbiota has an indispensable role in the onset and progression of obesity and T2DM. A reduced microbial diversity is linked to insulin resistance and energy metabolism, especially for the rise of the Firmicutes/Bacteroidetes ratio. Changes in metabolites followed by the gut dysbacteriosis are linked to the presence of T2DM. Moreover, endotoxin leakage and gut permeability caused by gut dysbacteriosis is more of a trigger for the onset and progression of T2DM. Research documents that natural products are remarkable arsenals of bioactive agents for the discovery of anti-T2DM drugs. Many studies have elucidated that the possible mechanisms of the anti-T2DM effects of natural products are remarkably linked to its regulation on the composition of gut microflora and the successive changes in metabolites directly or indirectly. This review presents a brief overview of the gut microbiota in T2DM and several relevant mechanisms, including short-chain fatty acids, biosynthesis and metabolism of branched-chain fatty acids, trimethylamine N-oxide, bile acid signaling, endotoxin leakage, and gut permeability, and describes how dietary natural products can improve T2DM via the gut microbiota.

Characterization of anaphylaxis reveals different metabolic changes depending on severity and triggers

BACKGROUND

Despite the increasing incidence of anaphylaxis, its underlying molecular mechanisms and biomarkers for appropriate diagnosis remain undetermined. The rapid onset and potentially fatal outcome in the absence of managed treatment prevent its study. Up today, there are still no known biomarkers that allow an unequivocal diagnosis. Therefore, the aim of this study was to explore metabolic changes in patients suffering anaphylactic reactions depending on the trigger (food and/or drug) and severity (moderate and severe) in a real-life set-up.

METHODS

Eighteen episodes of anaphylaxis, one per patient, were analysed. Sera were collected during the acute phase (T1), the recovery phase (T2) and around 2-3 months after the anaphylactic reaction (T0: basal state). Reactions were classified following an exhaustive allergological evaluation for severity and trigger. Sera samples were analysed using untargeted metabolomics combining liquid chromatography coupled to mass spectrometry (LC-MS) and proton nuclear magnetic resonance spectroscopy (¹ H-NMR).

RESULTS

'Food T1 vs T2' and 'moderate T1 vs T2' anaphylaxis comparisons showed clear metabolic patterns during the onset of an anaphylactic reaction, which differed from those induced by drugs, food + drug or severe anaphylaxis. Moreover, the model of food anaphylaxis was able to distinguish the well-characterized IgE (antibiotics) from non-IgE-mediated anaphylaxis (nonsteroidal anti-inflammatory drugs), suggesting a differential metabolic pathway associated with the mechanism of action. Metabolic differences between 'moderate vs severe' at the acute phase T1 and at basal state T0 were studied. Among the altered metabolites, glucose, lipids, cortisol, betaine and oleamide were observed altered.

CONCLUSIONS

The results of this exploratory study provide the first evidence that different anaphylactic triggers or severity induce differential metabolic changes along time or at specific time-point, respectively. Besides, the basal status T0 might identify high-risk patients, thus opening new ways to understand, diagnose and treat anaphylaxis.

Impact of gestational electronic cigarette vaping on amino acid signature profile in the pregnant mother and the fetus

Background

Electronic cigarettes (e-cigs) are a form of tobacco product that has become increasingly popular over the past decade. Despite the known health consequences of tobacco product exposure during pregnancy, a substantial number of daily smokers will continue to smoke during pregnancy. Our current knowledge on the effects of e-cig aerosol exposure during pregnancy is limited to a small number of animal studies, which have identified several e-cig aerosol-induced disruptions to the physiology of normal development.

Methods

To further assess the impact of prenatal e-cig aerosol exposure on maternal and fetal health, we examined the amino acid signature profiles in maternal and fetal plasma, as well as in the fetal lungs, a sensitive target organ for prenatal tobacco product exposure. Pregnant Sprague Dawley rats were randomly assigned to one of three groups and were exposed to either e-cig aerosols containing nicotine, e-cig aerosols without nicotine, or room air. Dams were exposed utilizing a state-of-the-art custom engineered e-cig vaping system that is compatible with commercially available e-cig atomizers and enables a translational inhalation delivery method comparable to human vaping.

Results

We determined that gestational exposure to e-cig aerosols results in significant alterations to the amino acid profile in the maternal and fetal compartments, including the fetal lungs. The data shows a targeted disruption to the nitric oxide pathway, branched-chain amino acid metabolism, fetal protein synthesis, and urea cycle.

Conclusion

The data presented herein provides additional support that gestational e-cig aerosol exposure can impact crucial biological processes and exemplifies the need for extensive research on exposure to e-cig aerosols.

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First report of e-cig induced alterations to maternal/fetal amino acid profile.

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Translational vaping paradigm utilizing custom engineered vaping system.

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Analysis of amino acids show gestational e-cig exposure has significant effects.

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Fetal lungs may be a sensitive target to gestational e-cig aerosol exposure.

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Marker of dysregulation in branched-chain amino acid metabolism and urea cycle.

Baicalein Delays H2O2-Induced Astrocytic Senescence through Inhibition of Senescence-Associated Secretory Phenotype (SASP), Suppression of JAK2/STAT1/NF-κB Pathway, and Regulation of Leucine Metabolism

Baicalein is an active ingredient extracted from the dried roots of the Scutellaria baicalensis Georgi. It has been demonstrated to improve memory impairment in multiple animal models; however, the underlying mechanisms remain ambiguous. The accumulation of senescent astrocytes and senescence-associated secretory phenotype (SASP) secreted by senescent astrocytes has been deemed as potential contributors to neurodegenerative diseases. Therefore, this study explored the protective effects of baicalein against astrocyte senescence and investigated the molecular mechanisms and metabolic mechanisms of baicalein against astrocyte senescence. Our results demonstrated that treatment with baicalein protects T98G cells from H₂O₂-induced damage, delays cell senescence, inhibits the secretion of SASP (IL-6, IL-8, TNF-α, CXCL1, and MMP-1), and inhibits SASP-related pathways NF-κB and JAK2/STAT1. ¹H NMR metabolomics analysis and correlation analysis revealed that leucine was significantly correlated with SASP factors. Further study demonstrated that supplement with leucine could restrain SASP secretion, and baicalein could significantly increase leucine level through down-regulation of BCAT1 and up-regulation of SLC7A5 expression. The above results revealed that baicalein exerted protective and antisenescence effects in H₂O₂-induced T98G cells possibly through inhibition of SASP, suppression of JAK2/STAT1/NF-κB pathway, and regulation of leucine metabolism. Consistent results were obtained in primary astrocytes of newborn SD rats, which suggests that baicalein significantly increases viabilities, delays senescence, inhibits IL-6 secretion, and increases leucine level in H₂O₂-induced primary astrocytes.

Dietary Avian Proteins Are Comparable to Soybean Proteins on the Atherosclerosis Development and Fatty Liver Disease in Apoe-Deficient Mice

Background and aim: The type and amount of dietary protein has become a topic of renewed interest in light of their involvement in metabolic diseases, atherosclerosis and thrombosis. However, little attention has been devoted to the effect of avian proteins despite their wide human consumption. The aim was to investigate the influence of chicken and turkey as sources of protein compared with that of soybean on atherosclerosis and fatty liver disease. Methods and results: To this purpose, male and female Apoe-deficient were fed purified Western diets differing in their protein sources for 12 weeks. After this period, blood, liver, aortic tree and heart base samples were taken for analyses of plasma lipids and atherosclerosis. Plasma triglycerides, non-esterified fatty acids, esterified cholesterol levels and radical oxygen species in lipoproteins changed depending on the diet and sex. Females consuming the turkey protein-containing diet showed decreased atherosclerotic foci, as evidenced by the en face atherosclerosis analyses. The presence of macrophages and smooth muscle cells in plaques were not modified, and no changes were observed in hepatic lipid droplets in the studied groups either. Paraoxonase activity was higher in the group consuming turkey protein without sex differences, but only in females, it was significantly associated with aortic lesion areas. Conclusions: Compared to soybean protein, the consumption of avian proteins depending on sex resulted in similar or lower atherosclerosis development and comparable hepatic steatosis.

Endothelial cell and T-cell crosstalk: Targeting metabolism as a therapeutic approach in chronic inflammation

The role of metabolic reprogramming in the coordination of the immune response has gained increasing consideration in recent years. Indeed, it has become clear that changes in the metabolic status of immune cells can alter their functional properties. During inflammation, T cells need to generate sufficient energy and biomolecules to support growth, proliferation, and effector functions. Therefore, T cells need to rearrange their metabolism to meet these demands. A similar metabolic reprogramming has been described in endothelial cells, which have the ability to interact with and modulate the function of immune cells. In this overview, we will discuss recent insights in the complex crosstalk between endothelial cells and T cells as well as their metabolic reprogramming following activation. We highlight key components of this metabolic switch that can lead to the development of new therapeutics against chronic inflammatory disorders. LINKED ARTICLES: This article is part of a themed issue on Cellular metabolism and diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.10/issuetoc.

The SARS-CoV-2 induced targeted amino acid profiling in patients at hospitalized and convalescent stage

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has induced an ongoing global health crisis. Here we utilized a combination of targeted amino acids (AAs) and clinical biochemical profiling to analyze the plasma of coronavirus disease 2019 (COVID-19) subjects at the hospitalization stage and 1-month post-infection convalescent stage, respectively, to investigate the systematic injury during COVID-19 disease progress. We found the virus-induced inflammatory status and reduced liver synthesis capacity in hospitalized patients, which manifested with increased branched-chain AAs (BCAAs), aromatic AAs (AAAs), one-carbon related metabolites, and decreased methionine. Most of these disturbances during infection recover except for the increased levels of medium-chain acylcarnitines (ACs) in the convalescent subjects, implying the existence of incomplete fatty acids oxidation during recovery periods. Our results suggested that the imbalance of the AA profiling in COVID-19 patients. The majority of disturbed AAs recovered in 1 month. The incomplete fatty acid oxidation products suggested it might take longer time for convalescent patients to get complete recovery.

Inhibition of the mTORC1/NF-κB Axis Alters Amino Acid Metabolism in Human Hepatocytes

In addition to serving as the building blocks for protein synthesis, amino acids can be used as an energy source, through catabolism. The transamination, oxidative deamination, and decarboxylation processes that occur during amino acid catabolism are catalyzed by specific enzymes, including aspartate aminotransferase (AST), glutamate dehydrogenase (GDH), glutamic acid decarboxylase (GAD), and ornithine decarboxylase (ODC); however, the overall molecular mechanisms through which amino acid catabolism occurs remain largely unknown. To examine the role of mechanistic target of rapamycin complex 1 (mTORC1) on amino acid catabolism, mTORC1 was inactivated by rapamycin or shRNA targeting Raptor, versus activated by overexpressing Rheb or amino acids in human hepatocytes. The expression of amino acid catabolic genes and related transcription factor was investigated by RT/real-time PCR and western blot analysis. A few types of amino acid metabolite were examined by ELISA and HPLC analysis. The data showed that inactivated mTORC1 resulted in inhibition of NF-κB and the expression of AST, GDH, GAD, and ODC, whereas activated mTORC1 enhanced NF-κB activation and the expression levels of the catabolism-associated genes. Further, inhibition of NF-κB reduced the expression levels of AST, GDH, GAD, and ODC. mTORC1 upregulated NF-κB activation and the expression of AST and ODC in response to glutamate and ornithine treatments, whereas rapamycin inhibited the utilization of glutamate and ornithine in hepatocytes. Taken together, these results indicated that the mTORC1/NF-κB axis modulates the rate of amino acid catabolism by regulating the expression of key catabolic enzymes in hepatocytes.

Endothelial Dysfunction and Extra-Articular Neurological Manifestations in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory autoimmune disease that affects about 1% of the global population, with a female–male ratio of 3:1. RA preferably affects the joints, with consequent joint swelling and deformities followed by ankylosis. However, evidence has accumulated showing that patients suffering from RA can also develop extra-articular manifestations, including cardiovascular disease states, neuropathies, and multiorgan dysfunction. In particular, peripheral nerve disorders showed a consistent impact in the course of the disease (prevalence about 20%) mostly associated to vasculitis of the nerve vessels leading to vascular ischemia, axonal degeneration, and neuronal demyelination. The pathophysiological basis of this RA-associated microvascular disease, which leads to impairment of assonal functionality, is still to be better clarified. However, endothelial dysfunction and alterations of the so-called brain-nerve barrier (BNB) seem to play a fundamental role. This review aims to assess the potential mechanisms underlying the impairment of endothelial cell functionality in the development of RA and to identify the role of dysfunctional endothelium as a causative mechanism of extra-articular manifestation of RA. On the other hand, the potential impact of lifestyle and nutritional interventions targeting the maintenance of endothelial cell integrity in patients with RA will be discussed as a potential option when approaching therapeutic solutions in the course of the disease.

New Insights Into Mitochondrial Dysfunction at Disease Susceptibility Loci in the Development of Type 2 Diabetes

This study investigated the potential genetic mechanisms which underlie adipose tissue mitochondrial dysfunction in Type 2 diabetes (T2D), by systematically identifying nuclear-encoded mitochondrial genes (NEMGs) among the genes regulated by T2D-associated genetic loci. The target genes of these 'disease loci' were identified by mapping genetic loci associated with both disease and gene expression levels (expression quantitative trait loci, eQTL) using high resolution genetic maps, with independent estimates co-locating to within a small genetic distance. These co-locating signals were defined as T2D-eQTL and the target genes as T2D cis-genes. In total, 763 cis-genes were associated with T2D-eQTL, of which 50 were NEMGs. Independent gene expression datasets for T2D and insulin resistant cases and controls confirmed that the cis-genes and cis-NEMGs were enriched for differential expression in cases, providing independent validation that genetic maps can identify informative functional genes. Two additional results were consistent with a potential role of T2D-eQTL in regulating the 50 identified cis-NEMGs in the context of T2D risk: (1) the 50 cis-NEMGs showed greater differential expression compared to other NEMGs and (2) other NEMGs showed a trend towards significantly decreased expression if their expression levels correlated more highly with the subset of 50 cis-NEMGs. These 50 cis-NEMGs, which are differentially expressed and associated with mapped T2D disease loci, encode proteins acting within key mitochondrial pathways, including some of current therapeutic interest such as the metabolism of branched-chain amino acids, GABA and biotin.

Metabolomic profiling reveals amino acid and carnitine alterations as metabolic signatures in psoriasis

High-throughput metabolite profiling provides the opportunity to reveal metabolic mechanisms and identify biomarkers. Psoriasis is an immune-mediated chronic inflammatory disease. However, the role of metabolism in psoriasis pathogenesis remains unclear. Methods: Plasma samples of individuals (45 psoriasis and 45 sex-, age-, and BMI-matched healthy controls) were collected. Non-targeted metabolomics and amino acid- or carnitine-targeted metabolomics were conducted, then, plasma samples of mice induced by imiquimod (IMQ) were subjected to the amino acid- and carnitine-targeted metabolomic profiling. Flow cytometry was used to study the effect of L-carnitine (LC(C0)) on IMQ-induced psoriatic inflammation. Results: Through the non-targeted metabolomics approach, we detected significantly altered amino acids and carnitines in psoriasis patients. Amino acid-targeted metabolomic profiling identified 37 amino acids altered in psoriasis, of these 23 were markedly upregulated, including essential amino acids (EAAs), and branched-chain amino acids (BCAAs), whereas glutamine, cysteine, and asparagine were significantly down-regulated. Carnitine-targeted metabolomic profiling identified 40 significantly altered carnitines, 14 of which included palmitoylcarnitine (C16) and were markedly downregulated in psoriasis, whereas hexanoylcarnitine (C6) and 3-OH-octadecenoylcarnitine (C18:1-OH) were significantly upregulated. Interestingly, glutamine, asparagine, and C16 levels were negatively correlated with the PASI score. Moreover, a higher abundance of LC(C0) was associated with markedly reduced IMQ-induced epidermal thickening and infiltration of Th17 cells in skin lesions, indicating LC(C0) supplementation as a potential therapy for psoriasis treatment. Conclusion: Our results suggested the metabolism of amino acids and carnitines are significantly altered in psoriasis, especially the metabolism of EAAs, BCAAs, and LC(C0), which may play key roles in the pathogenesis of psoriasis.

mTORC1 (Mechanistic Target of Rapamycin Complex 1) Signaling in Endothelial and Smooth Muscle Cells Is Required for Vascular Function

mTORC1 (Mechanistic target of rapamycin complex 1) serves as a molecular hub and intracellular energy sensor that regulate various cellular processes. Emerging evidence points to mTORC1 signaling as a critical regulator of cardiovascular function with implications for cardiovascular disease. Here, we show that selective disruption of mTORC1, through conditional Raptor gene deletion, in endothelial or smooth muscle cells alter vascular function. Endothelial cell-specific Raptor deletion results in reduced relaxation responses evoked by acetylcholine in the aorta but not in the mesenteric artery. Of note, endothelial-specific Raptor deletion did not affect endothelial-independent vasorelaxation nor the contractile responses of the aorta or mesenteric artery. Interestingly, endothelial Raptor haploinsufficiency did not alter vascular endothelial function but attenuated the endothelial dysfunction evoked by angiotensin II. Smooth muscle cell-specific conditional deletion of Raptor reduces both endothelial- and smooth muscle-dependent relaxation responses as well as receptor-dependent and -independent contractility in the aorta. This was associated with activation of autophagy signaling. Notably, the changes in vascular function evoked by endothelial and smooth muscle Raptor deletion were independent of changes in blood pressure and heart rate. Together, these data suggest that vascular mTORC1 signaling is a critical regulator of vascular endothelial and smooth muscle function. mTORC1 signaling may represent a potential target for the treatment of vascular diseases associated with altered mTORC1 activity.

Brain energy metabolism and multiple sclerosis: progress and prospects

Multiple sclerosis (MS) is an autoimmune disease accompanied with nerve pain and paralysis. Although various pathogenic causes of MS have been suggested, including genetic and environmental factors, how MS occurs remains unclear. Moreover, MS should be diagnosed based on clinical experiences because of no disease-specific biomarker and currently available treatments for MS just can reduce relapsing frequency or severity with little effects on disease disability. Therefore, more efforts are required to identify pathophysiology of MS and diagnosis markers. Recent evidence indicates another aspect of MS pathogenesis, energy failure in the central nervous system (CNS). For instance, inflammation that is a characteristic MS symptom and occurs frequently in the CNS of MS patients can result into energy failure in mitochondria and cytosol. Indeed, metabolomics studies for MS have reported energy failure in oxidative phosphorylation and alteration of aerobic glycolysis. Therefore, studies on the metabolism in the CNS may provide another insight for understanding complexity of MS and pathogenesis, which would facilitate the discovery of promising strategies for developing therapeutics to treat MS. This review will provide an overview on recent progress of metabolomic studies for MS, with a focus on the fluctuation of energy metabolism in MS.

Branched chain amino acids and carbohydrate restriction exacerbate ketogenesis and hepatic mitochondrial oxidative dysfunction during NAFLD

Mitochondrial adaptation during non-alcoholic fatty liver disease (NAFLD) include remodeling of ketogenic flux and sustained tricarboxylic acid (TCA) cycle activity, which are concurrent to onset of oxidative stress. Over 70% of obese humans have NAFLD and ketogenic diets are common weight loss strategies. However, the effectiveness of ketogenic diets toward alleviating NAFLD remains unclear. We hypothesized that chronic ketogenesis will worsen metabolic dysfunction and oxidative stress during NAFLD. Mice (C57BL/6) were kept (for 16-wks) on either a low-fat, high-fat, or high-fat diet supplemented with 1.5X branched chain amino acids (BCAAs) by replacing carbohydrate calories (ketogenic). The ketogenic diet induced hepatic lipid oxidation and ketogenesis, and produced multifaceted changes in flux through the individual steps of the TCA cycle. Higher rates of hepatic oxidative fluxes fueled by the ketogenic diet paralleled lower rates of de novo lipogenesis. Interestingly, this metabolic remodeling did not improve insulin resistance, but induced fibrogenic genes and inflammation in the liver. Under a chronic "ketogenic environment," the hepatocyte diverted more acetyl-CoA away from lipogenesis toward ketogenesis and TCA cycle, a milieu which can hasten oxidative stress and inflammation. In summary, chronic exposure to ketogenic environment during obesity and NAFLD has the potential to aggravate hepatic mitochondrial dysfunction.

Mechanistic Target of Rapamycin Complex 1 Signaling Modulates Vascular Endothelial Function Through Reactive Oxygen Species

Background

The mechanistic target of rapamycin complex 1 (mTORC1) is an important intracellular energy sensor that regulates gene expression and protein synthesis through its downstream signaling components, the S6‐kinase and the ribosomal S6 protein. Recently, signaling arising from mTORC1 has been implicated in regulation of the cardiovascular system with implications for disease. Here, we examined the contribution of mTORC1 signaling to the regulation of vascular function.

Methods and Results

Activation of mTORC1 pathway in aortic rings with leucine or an adenoviral vector expressing a constitutively active S6‐kinase reduces endothelial‐dependent vasorelaxation in an mTORC1‐dependent manner without affecting smooth muscle relaxation responses. Moreover, activation of mTORC1 signaling in endothelial cells increases reactive oxygen species (ROS) generation and ROS gene expression resulting in a pro‐oxidant gene environment. Blockade of ROS signaling with Tempol restores endothelial function in vascular rings with increased mTORC1 activity indicating a crucial interaction between mTORC1 and ROS signaling. We then tested the role of nuclear factor‐κB transcriptional complex in connecting mTORC1 and ROS signaling in endothelial cells. Blockade of inhibitor of nuclear factor κ‐B kinase subunit β activity with BMS‐345541 prevented the increased ROS generation associated with increased mTORC1 activity in endothelial cells but did not improve vascular endothelial function in aortic rings with increased mTORC1 and ROS signaling.

Conclusions

These results implicate mTORC1 as a critical molecular signaling hub in the vascular endothelium in mediating vascular endothelial function through modulation of ROS signaling.

A Protein/Lipid Preload Attenuates Glucose-Induced Endothelial Dysfunction in Individuals with Abnormal Glucose Tolerance

Postprandial hyperglycemia interferes with vascular reactivity and is a strong predictor of cardiovascular disease. Macronutrient preloads reduce postprandial hyperglycemia in subjects with impaired glucose tolerance (IGT) or type 2 diabetes (T2D), but the effect on endothelial function is unknown. Therefore, we examined whether a protein/lipid preload can attenuate postprandial endothelial dysfunction by lowering plasma glucose responses in subjects with IGT/T2D. Endothelial function was assessed by the reactive hyperemia index (RHI) at fasting, 60 min and 120 min during two 75 g oral glucose tolerance tests (OGTTs) preceded by either water or a macronutrient preload (i.e., egg and parmesan cheese) in 22 volunteers with IGT/T2D. Plasma glucose, insulin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), glucagon, free fatty acids, and amino acids were measured through each test. RHI negatively correlated with fasting plasma glucose. During the control OGTT, RHI decreased by 9% and its deterioration was associated with the rise in plasma glucose. The macronutrient preload attenuated the decline in RHI and markedly reduced postprandial glycemia. The beneficial effect of the macronutrient preload on RHI was proportional to the improvement in glucose tolerance and was associated with the increase in plasma GLP-1 and arginine levels. In conclusion, a protein/lipid macronutrient preload attenuates glucose-induced endothelial dysfunction in individuals with IGT/T2D by lowering plasma glucose excursions and by increasing GLP-1 and arginine levels, which are known regulators of the nitric oxide vasodilator system.

Aerobic training prevents cardiometabolic changes triggered by myocardial infarction in ovariectomized rats

This study aimed to evaluate the impact of aerobic training (AT) on autonomic, cardiometabolic, ubiquitin-proteasome activity, and inflammatory changes evoked by myocardial infarction (MI) in ovariectomized rats. Female Wistar rats were ovariectomized and divided into four groups: sedentary + sham (SS), sedentary + MI (SI), AT + sham surgery (TS), AT + MI (TI). AT was performed on a treadmill for 8 weeks before MI. Infarcted rats previously subjected to AT presented improved physical capacity, increased interleukin-10, and decreased pro-inflammatory cytokines. Metabolomic analysis identified and quantified 62 metabolites, 9 were considered significant by the Vip Score. SS, SI, and TS groups presented distinct metabolic profiles; however, TI could not be distinguished from the SS group. MI dramatically increased levels of dimethylamine, and AT prevented this response. Our findings suggest that AT may be useful in preventing the negative changes in functional, inflammatory, and metabolic parameters related to MI in ovariectomized rats.

Sexual Dimorphism of Metabolomic Profile in Arterial Hypertension

Metabolomic studies have demonstrated the existence of biological signatures in blood of patients with arterial hypertension, but no study has hitherto reported the sexual dimorphism of these signatures. We compared the plasma metabolomic profiles of 28 individuals (13 women and 15 men) with essential arterial hypertension with those of a healthy control group (18 women and 18 men), using targeted metabolomics. Among the 188 metabolites explored, 152 were accurately measured. Supervised OPLS-DA (orthogonal partial least squares-discriminant analysis) showed good predictive performance for hypertension in both sexes (Q²cum = 0.59 in women and 0.60 in men) with low risk of overfitting (p-value-CV ANOVA = 0.004 in women and men). Seventy-five and 65 discriminant metabolites with a VIP (variable importance for the projection) greater than 1 were evidenced in women and men, respectively. Both sexes showed a considerable increase in phosphatidylcholines, a decrease in C16:0 with an increase in C28:1 lysophosphatidylcholines, an increase in sphingomyelins, as well as an increase of symmetric dimethylarginine (SDMA), acetyl-ornithine and hydroxyproline. Twenty-nine metabolites, involved in phospholipidic and cardiac remodeling, arginine/nitric oxide pathway and antihypertensive and insulin resistance mechanisms, discriminated the metabolic sexual dimorphism of hypertension. Our results highlight the importance of sexual dimorphism in arterial hypertension.

Coordinated Modulation of Energy Metabolism and Inflammation by Branched-Chain Amino Acids and Fatty Acids

As important metabolic substrates, branched-chain amino acids (BCAAs) and fatty acids (FAs) participate in many significant physiological processes, such as mitochondrial biogenesis, energy metabolism, and inflammation, along with intermediate metabolites generated in their catabolism. The increased levels of BCAAs and fatty acids can lead to mitochondrial dysfunction by altering mitochondrial biogenesis and adenosine triphosphate (ATP) production and interfering with glycolysis, fatty acid oxidation, the tricarboxylic acid cycle (TCA) cycle, and oxidative phosphorylation. BCAAs can directly activate the mammalian target of rapamycin (mTOR) signaling pathway to induce insulin resistance, or function together with fatty acids. In addition, elevated levels of BCAAs and fatty acids can activate the canonical nuclear factor-κB (NF-κB) signaling pathway and inflammasome and regulate mitochondrial dysfunction and metabolic disorders through upregulated inflammatory signals. This review provides a comprehensive summary of the mechanisms through which BCAAs and fatty acids modulate energy metabolism, insulin sensitivity, and inflammation synergistically.

Lipid-Induced Mechanisms of Metabolic Syndrome

Metabolic syndrome (MetS) has a worldwide tendency to increase and depends on many components, which explains the complexity of diagnosis, approaches to the prevention, and treatment of this pathology. Insulin resistance (IR) is the crucial cause of the MetS pathogenesis, which develops against the background of abdominal obesity. In light of recent evidence, it has been shown that lipids, especially fatty acids (FAs), are important signaling molecules that regulate the signaling pathways of insulin and inflammatory mediators. On the one hand, the lack of n-3 polyunsaturated fatty acids (PUFAs) in the body leads to impaired molecular mechanisms of glucose transport, the formation of unresolved inflammation. On the other hand, excessive formation of free fatty acids (FFAs) underlies the development of oxidative stress and mitochondrial dysfunction in MetS. Understanding the molecular mechanisms of the participation of FAs and their metabolites in the pathogenesis of MetS will contribute to the development of new diagnostic methods and targeted therapy for this disease. The purpose of this review is to highlight recent advances in the study of the effect of fatty acids as modulators of insulin response and inflammatory process in the pathogenesis and treatment for MetS.

1-Deoxynojirimycin in Mulberry (Morus indica L.) Leaves Ameliorates Stable Angina Pectoris in Patients With Coronary Heart Disease by Improving Antioxidant and Anti-inflammatory Capacities

Objective: Stable angina pectoris (SAP) in patients with coronary heart disease (CHD) and blood stasis syndrome (BSS) is a potentially serious threat to public health. NF-κB signaling is associated with angina pectoris. 1-Deoxynojirimycin (DNJ), which is a unique polyhydroxy alkaloid, is the main active component in mulberry (Morus indica L.) leaves and may exhibit protective properties in the prevention of SAP in patients with CHD by affecting the NF-κB pathway.

Methods: DNJ was purified from mulberry leaves by using a pretreated cation exchange chromatography column. A total of 144 SAP patients were randomly and evenly divided into experimental (DNJ treatment) and control (conventional treatment) groups. Echocardiography and ascending aortic elasticity were evaluated. The changes in inflammatory, oxidative, and antioxidant factors, including C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), superoxide dismutase (SOD), and malondialdehyde (MDA), were measured before and after a 4-week treatment. Self-Rating Anxiety Scale (SAS) and Hamilton Depression Scale (HAMD) scores were compared between the two groups. The improvement in SAP score, associated symptoms, and BSS was also investigated. The levels of IkB kinase (IKK), nuclear factor-kappa B (NF-κB), and inhibitor of kappa B α (IkBα) were measured by Western blot.

Results: After the 4-week treatment, DNJ increased left ventricular ejection fraction and reduced left ventricular mass index, aortic distensibility, and atherosclerosis index (p < 0.05). DNJ intervention increased angina-free walking distance (p < 0.05). DNJ significantly reduced the levels of hs-CRP, IL-6, TNF-a, MDA, SAS, HAMD, AP, and BSS scores and increased SOD level (p < 0.05). The total effective rate was significantly increased (p < 0.05). The symptoms of angina attack frequency, nitroglycerin use, chest pain and tightness, shortness of breath, and emotional upset were also improved. DNJ reduced IKK and NF-κB levels and increased IkBα level (p < 0.05).

Conclusion: The DNJ in mulberry leaves improved the SAP of patients with CHD and BSS by increasing their antioxidant and anti-inflammatory capacities.

The impact of dietary protein intake on longevity and metabolic health

Lifespan and metabolic health are influenced by dietary nutrients. Recent studies show that a reduced protein intake or low-protein/high-carbohydrate diet plays a critical role in longevity/metabolic health. Additionally, specific amino acids (AAs), including methionine or branched-chain AAs (BCAAs), are associated with the regulation of lifespan/ageing and metabolism through multiple mechanisms. Therefore, methionine or BCAAs restriction may lead to the benefits on longevity/metabolic health. Moreover, epidemiological studies show that a high intake of animal protein, particularly red meat, which contains high levels of methionine and BCAAs, may be related to the promotion of age-related diseases. Therefore, a low animal protein diet, particularly a diet low in red meat, may provide health benefits. However, malnutrition, including sarcopenia/frailty due to inadequate protein intake, is harmful to longevity/metabolic health. Therefore, further study is necessary to elucidate the specific restriction levels of individual AAs that are most effective for longevity/metabolic health in humans.

Metabolic disturbances in synovial fluid are involved in the onset of synovitis in heifers with acute ruminal acidosis

Acute ruminal acidosis (ARA) is the result of increased intake of highly fermentable carbohydrates, which frequently occurs in dairy cattle and is associated with aseptic polysynovitis. To characterise the metabolic changes in the joints of animals with ARA, we performed an untargeted gas chromatography-mass spectrometry (GC-MS)-based metabolomic analysis of synovial fluid. Seven heifers were challenged with an intraruminal oligofructose overload (13 g/kg of body weight [BW]) dissolved in water. Synovial fluid samples were collected at 0, 9 and 24 h post-overload. Metabolome analysis revealed the presence of 67 metabolites. At 9 h post-overload, glyceric acid, cellobiose, fructose and lactic acid were all increased, whereas at 24 h, sorbitol, lactic acid and fructose levels were all increased >10-fold. At 24 h, citric acid and threonine levels were significantly reduced. We detected increased L- and D-lactate, and the presence of interleukin-6 (IL-6) in synovial fluid. Furthermore, using bovine fibroblast-like synoviocytes, we observed that D-lactate induces IL-6 synthesis. Our results suggest that ARA produces severe metabolomic changes in synovial fluid, including disturbances in starch and sucrose metabolism, and increased lactate levels. These changes were observed prior to the appearance of synovitis, suggesting a potential role in the onset of polysynovitis.

Branched Chain Amino Acids Protects Rat Mesangial Cells from High Glucose by Modulating TGF-β1 and BMP-7

AIM

Branched-chain amino acids (BCAAs) have been reported owning curative effects in early diabetic nephropathy. However, the mechanisms of its action have not been elucidated. The aim of this study is to investigate the effect of possible mechanism(s) of BCAAs on cultured rat mesangial cells (RMCs).

METHODS

RMCs were treated with high glucose (30 mmol/L) and BCAAs (10 mmol/L) respectively. Cell proliferation was detected using an MTT assay. Expression of transforming growth factor (TGF)-β1 and gremlin mRNA was detected by semiquantitative reverse-transcription (RT) PCR. TGF-β1 and fibronectin (FN) protein levels were measured using enzyme-linked immunosorbent assays (ELISAs). Gremlin, bone morphogenic protein (BMP)-7, and Smad2/3 proteins were detected by immunofluorescence. Smad1/5/8 and phosphorylated (p)-Smad1/5/8 were detected by Western blotting.

RESULTS

The proliferation rate of the RMCs in the high glucose group alone was 1.45-times of cells in the CON group, and it was reduced by 32% upon co-treatment with BCAAs. The expression of TGF-β1, gremlin, p-Smd2/3 and FN mRNA or protein in the HG group was higher than that in the CON group. In the BCAAs group, the corresponding levels were lower than that in HG group. The expression of BMP-7 and p-Smad1/5/8 were significantly lower in the HG group than in the CON group. Moreover, the expression of BMP-7 and p-Smad1/5/8 were higher in the BCAAs group than in the HG group.

CONCLUSION

BCAAs showed an antidiabetic effect via reducing TGF-β1-Smad2/3 pathway and Gremlin expression and upregulating BMP-7-Smad1/5/8 pathway in rat mesangial cells, consequently lessening ECM deposition in renal tissue.

Metabonomic study of the protective effect of Fukeqianjin formula on multi-pathogen induced pelvic inflammatory disease in rats

Background

Fukeqianjin formula has been effectively used in the treatment of pelvic inflammatory disease (PID) and the related complications in clinic. Although there have been some studies about the underlying mechanism that focus on its anti-inflammatory and immunoregulatory activities. But the mechanism is still not fully understood. The aim of this study was to investigate the alteration of plasma metabolic profiles in PID rats and the regulatory effect of Fukeqianjin formula on potential biomarkers.

Methods

Pelvic inflammatory model was established by intrauterine inoculation of multiple pathogens combined with mechanical injury of endometrium. Rats were randomly divided into normal group, model group, azithromycin group, high-and low-dose of Fukeqianjin formula treatment group (FF-H, and FF-L, respectively). After 14 days of intragastric administration, the plasm levels of interleukin-1β (IL-1β) and nitric oxide (NO) were measured. To further recognize and identify potential biomarkers and metabolic pathways, an ultra-performance liquid chromatography-quadrupole-Exactive Orbitrap-mass spectrometry (UPLC-Q-Exactive Orbitrap-MS) metabonomic method combined with multivariate analyses including principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA), was employed to analyze the metabolic profiling.

Results

Compared with normal group, the plasma levels of IL-1β and NO were significantly increased in the PID model group (P < 0. 05), and obviously decreased after high-dose intervention of Fukeqianjin formula (P < 0. 01). The PCA, PLS-DA and OPLS-DA analysis showed that PID rats were clearly separated from normal rats. Compared with the PID model group, the metabolite profiles of Fukeqianjin formula treatment group was gradually restored to normal. Meanwhile, 14 potential metabolite biomarkers, which were mainly related to the metabolic pathways of intervening glycerophospholipid metabolism, linoleic acid metabolism/alpha-linolenic acid metabolism, amino acid metabolism, arachidonic acid metabolism, and unsaturated fatty acids biosynthesis, have been identified. Fukeqianjin formula exerts good regulatory effect on the abnormal metabolism of PID rats.

Conclusions

Intrauterine inoculation of multiple pathogens combined with mechanical injury of endometrium could significantly disturb the plasma metabolic profiles of rats. Fukeqianjin formula has potential therapeutic effect on multi-pathogen-induced PID by ameliorating metabolism disorders and alleviating the inflammatory response.

Electronic supplementary material

The online version of this article (10.1186/s13020-018-0217-6) contains supplementary material, which is available to authorized users.

Branched-chain amino acids promote endothelial dysfunction through increased reactive oxygen species generation and inflammation

Branched‐chain amino acids (BCAA: leucine, isoleucine and valine) are essential amino acids implicated in glucose metabolism and maintenance of correct brain function. Elevated BCAA levels can promote an inflammatory response in peripheral blood mononuclear cells. However, there are no studies analysing the direct effects of BCAA on endothelial cells (ECs) and its possible modulation of vascular function. In vitro and ex vivo studies were performed in human ECs and aorta from male C57BL/6J mice, respectively. In ECs, BCAA (6 mmol/L) increased eNOS expression, reactive oxygen species production by mitochondria and NADPH oxidases, peroxynitrite formation and nitrotyrosine expression. Moreover, BCAA induced pro‐inflammatory responses through the transcription factor NF‐κB that resulted in the release of intracellular adhesion molecule‐1 and E‐selectin conferring endothelial activation and adhesion capacity to inflammatory cells. Pharmacological inhibition of mTORC1 intracellular signalling pathway decreased BCAA‐induced pro‐oxidant and pro‐inflammatory effects in ECs. In isolated murine aorta, BCAA elicited vasoconstrictor responses, particularly in pre‐contracted vessels and after NO synthase blockade, and triggered endothelial dysfunction, effects that were inhibited by different antioxidants, further demonstrating the potential of BCAA to induce oxidative stress with functional impact. In summary, we demonstrate that elevated BCAA levels generate inflammation and oxidative stress in ECs, thereby facilitating inflammatory cells adhesion and endothelial dysfunction. This might contribute to the increased cardiovascular risk observed in patients with elevated BCAA blood levels.