High dietary intake of aromatic amino acids increases risk of hypertension

Identification of serum metabolic markers in non-obese hypertensive patients using non-targeted metabolomics

The future of hypertension management lies in distinguishing disease subtypes for precise control. The underlying drivers and pathology of non-obese hypertension (J-HTN) remain unclear. There is a lack of biomarkers for the early identification of J-HTN. The aim of this study was to identify circulating metabolomic profiles that facilitate the early detection of J-HTN patients, thereby providing valuable insights for more targeted and precision-based therapies. A non-targeted metabolomics approach was used to quantify serum metabolites in 120 patients with newly diagnosed hypertension, and to determine the metabolomic characteristics of J-HTN and two types of obese hypertension (fat-dominant and muscle-dominant). 4 metabolites unique to J-HTN were identified, with lysophosphatidylcholine 22:6 (LysoPC(22:6/0:0)) standing out as the marker showing the most pronounced difference. Using the serum metabolome alone, we were able to distinguish J-HTN from other hypertensive patients. In a secondary validation with an independent cohort of 60 medically treated J-HTN patients, 3 metabolites, including LysoPC(22:6/0:0), remained significantly altered. The serum metabolic profiles identified in this study enable the early detection of J-HTN, with LysoPC(22:6/0:0) emerging as a highly promising biomarker. This metabolite may also correlate with the clinical efficacy of J-HTN treatments.

CKD patients comorbid with hypertension are associated with imbalanced gut microbiome

Intestinal flora has been linked to chronic kidney disease (CKD) and hypertension, respectively. This study aimed to investigate the microbial community among 54 individuals without CKD, 46 hypertensive CKD patients (CKD_HTN), and 48 non-hypertensive CKD patients. Variations in microbial diversity were detected in CKD. The Prevotella-dominated type progressively increased from CKD to CKD_HTN. Based on the variation patterns, we identified six distinct clusters. Klebsiella, Turicibacter, and Enterobacter were enriched in CKD, whereas Escherichia and Mogibacterium were elevated, and Blautia and Clostridium were reduced in CKD_HTN. Enhanced phenylalanine metabolism and siderophore group nonribosomal peptides biosynthesis from non-CKD to CKD were observed, particularly in CKD with hypertension. The connections between genera and KEGG pathways suggest an impact of microbial dysbiosis on metabolism. Our findings demonstrate that imbalances in gut microorganisms and functions are associated with increased susceptibility to hypertension in CKD patients and could be targeted for improving kidney function in CKD.

The relationship between dietary branched-chain and aromatic amino acids with the regulation of leptin and FTO genes in adipose tissue of patients undergoing abdominal surgery

Recent studies have suggested that the interaction between diet and an individual's genetic predisposition can determine the likelihood of obesity and various metabolic disorders. The current study aimed to examine the association of dietary branched-chain amino acids(BCAAs) and aromatic amino acids(AAAs) with the expression of the leptin and FTO genes in the visceral and subcutaneous adipose tissues of individuals undergoing surgery. This cross-sectional study was conducted on 136 Iranian adults, both men and women, aged ≥18 years. The samples were selected from patients admitted for abdominal surgeries. The dietary intake of BCAAs and AAAs was determined using a valid and reliable 168-item food frequency questionnaire. Using the quantitative PCR method, leptin and FTO mRNA expression was measured in both visceral and subcutaneous fat tissues. The mean age of the participants was 39.8 ± 12.7 years, and the mean intake of BCAAs and AAAs was 17.7 ± 0.9 and 9.3 ± 0.3% of protein per day, respectively. In overweight-obese patients(body mass index = 25-34.9 kg/m2), the intake of BCAAs(β:-0.75,95%CI:-1.47,-0.03), valine(β:-0.78,95%CI:-1.51,-0.05), and tyrosine(β:-0.81,95%CI:-1.55,-0.06) was inversely associated with FTO gene expression in subcutaneous fat tissue in adjusted model. In morbidly obese patients(body mass index ≥ 35 kg/m2), a higher intake of total BCAAs(β:1.10,95%CI:0.07-2.13), leucine(β:1.07,95%CI:0.03-2.13), and isoleucine(β:1.49,95%CI:0.46-2.52) was associated with an increase of leptin gene expression in subcutaneous fat tissue. Our findings suggest that dietary BCAA may associated with gene expression in adipose tissues, potentially influencing obesity-related metabolic pathways. Further prospective studies are warranted to validate results and elucidate the potential for dietary interventions targeting amino acids intake in obesity management.

Dietary amino acids intake and all-cause and cause-specific mortality: results from the Golestan Cohort Study

BACKGROUND

Less is known whether the amino acid composition of dietary protein sources effects on long-term health outcomes. We aimed to evaluate the association between dietary amino acid composition and all-cause and cause-specific mortality.

METHODS

This study used data from the Golestan Cohort Study, which was performed in the Golestan Province of Iran from January 2004 to June 2008. Mortality, which was the primary outcome, was ascertained through September 2022. The Cox proportional hazards regression models were used to determine the adjusted hazard ratios (HR) and 95% confidence intervals (CI) for mortality according to the quintiles of amino acid consumption, taking the third quintile as the reference.

RESULTS

A total of 47,337 participants (27,293 [57.7%] women) with a mean (standard deviation) age of 51.9 (8.9) years were included. During a median follow-up of 15 years, 9,231 deaths were documented. Regarding essential amino acid intakes, the HRs of all-cause mortality were 1.16 (95% CI, 1.07-1.26) in the first quintile, compared with the reference group (P for non-linear trend < 0.001). Similarly, non-linear associations were observed between risk of all-cause mortality and intake of branched-chain, aromatic, sulfur-containing, or non-essential amino acids (P for non-linear trend < 0.001 for all comparisons), with higher HRs for participants in the first quintiles. There was an age interaction for the associations between dietary amino acids and mortality (P for interaction ˂0.05). While high amino acid diets were detrimental in middle-aged adults (< 65 years), increased hazards of mortality were observed among older adults (≥ 65 years) with low amino acid intake.

CONCLUSIONS

This study showed the non-linear trend between amino acids intake and risk of mortality in the middle-aged and older Iranian population. Overall, our findings suggest that diets lower in amino acids were associated with increased hazards of mortality, particularly among older adults.

Interplay Between Plasma Glycine and Branched-Chain Amino Acids Contributes to the Development of Hypertension and Coronary Heart Disease

BACKGROUND

Higher levels of plasma glycine are linked to a reduced risk, while increased levels of total branched-chain amino acids (tBCAAs) are associated with a higher risk of essential hypertension and coronary heart disease (CHD). As these metabolic components are interconnected, analyzing the tBCAAs/glycine ratio may help to understand their interplay in the pathogenesis of cardiovascular disease.

METHODS

The Cox regression approach was combined with the development of novel genetic tools for assessments of associations between plasma metabolomic data (glycine, tBCAAs, and tBCAAs/glycine ratio) from the UK Biobank and the development of hypertension and CHD. Genome-wide association study was performed on 186 523 White UK Biobank participants to identify new independent genetic instruments for the 2-sample Mendelian randomization analyses. P-gain statistic >10 identified instruments associated with tBCAAs/glycine ratio significantly stronger compared with individual amino acids. Outcomes of genome-wide association study on hypertension and CHD were derived from the UK Biobank (nonoverlapping sample), FinnGen, and CARDIoGRAMplusC4D.

RESULTS

The tBCAAs/glycine ratio was prospectively associated with a higher risk of developing hypertension and CHD (hazard ratio quintile Q5 versus Q1, 1.196 [95% CI, 1.109-1.289] and 1.226 [95% CI, 1.160-1.296], respectively). Mendelian randomization analysis demonstrated that tBCAAs/glycine ratio (P-gain >10) was a risk factor for hypertension (meta-analyzed inverse-variance weighted causal estimate 0.45 log odds ratio/SD (95% CI, 0.26-0.64) and CHD (0.48 [95% CI, 0.29-0.67]) with an absolute effect significantly larger compared with the effect of glycine (-0.06 [95% CI, -0.1 to -0.03] and -0.08 [95% CI, -0.11 to -0.05], respectively) or tBCAAs (0.22 [95% CI, 0.09-0.34] and 0.12 [95% CI, 0.01-0.24], respectively).

CONCLUSIONS

The total BCAAs/glycine ratio is a key element of the metabolic signature contributing to hypertension and CHD, which may reflect biological pathways shared by glycine and tBCAAs.

Association between serum albumin concentration change trajectory and risk of hypertension: a cohort study in China

Background

We sought to assess the risk of hypertension based on the trajectory of changes in serum albumin concentrations.

Methods

A total of 11,946 nonhypertension adults aged 30-60 years who underwent at least 3 medical examinations between 2009 and 2016 were included in this study. Group-based trajectory models were obtained for 4 category groups, and logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each category group of serum albumin concentration and the risk of hypertension.

Results

During a mean follow-up period of 4.30 years, 1,537 hypertension events occurred in 11,946 subjects without hypertension. A high stable trajectory of serum albumin concentrations (OR, 0.70, 95% CI, 0.51-0.96) was associated with a significantly lower risk of developing hypertension. The results of the sensitivity analysis of the high stable trajectory (OR, 0.64, 95% CI, 0.43-0.96) remained statistically significant. Subjects with normal weight and those ≥45 years of age had a significantly lower risk of hypertension at moderate increase (P = 0.053 or 0.026) and high stable trajectories (P = 0.011 or 0.016). In males and overweight subjects, the risk of hypertension was significantly lower in the high stable trajectory (P = 0.038 or 0.044).

Conclusion

In this study, we found that moderate increase in serum albumin concentrations and a high stable trajectory were significantly associated with a reduced risk of hypertension in subjects aged ≥45 years and those with normal weight and that high stable serum albumin concentrations were significantly associated with a reduced risk of hypertension in males and overweight subjects.

Dietary amino acid profile and risk of hypertension: findings from the Ravansar cohort study

INTRODUCTION

Hypertension (HTN) is a significant global health concern associated with morbidity and mortality. Recent research has explored the potential relationship between dietary protein intake and the development of HTN. This study aims to investigate the association between dietary amino acids and the incidence of HTN.

METHODS

This nested case-control study utilized data from the Ravansar Non-Communicable Disease (RaNCD) Cohort Study. The study included 491 new HTN cases identified over a 6-year follow-up period. For each case, four controls were randomly selected through density sampling. A food frequency questionnaire (FFQ) consisting of 125 food items was used to calculate dietary amino acid intake. HTN was determined based on systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg and/or current use of antihypertensive medication in subjects without pre-existing HTN at the start of the cohort study. Conditional logistic regression was used to estimate crude and adjusted odds ratios for HTN risk.

RESULTS

The median intake of all amino acids was lower in patients with HTN compared to the control group. After adjusting for various variables in different models, the risk of developing HTN tended to increase with higher dietary amino acid intake (excluding tryptophan and acidic amino acids). Specifically, individuals in the third tertile had a higher risk of developing new HTN than those individuals in the lowest tertile, although this difference was not statistically significant (P > 0.05).

CONCLUSION

The findings suggest that there may be an association between increased dietary amino acid intake and the risk of developing HTN, although this association was not statistically significant in this study. Further investigations in diverse populations are needed to explore the relationship between amino acids and HTN, as well as to determine the potential positive and negative effects of specific amino acid patterns on hypertension.

Nuclear ATR lysine-tyrosylation protects against heart failure by activating DNA damage response

Dysregulated amino acid increases the risk for heart failure (HF) via unclear mechanisms. Here, we find that increased plasma tyrosine and phenylalanine levels are associated with HF. Increasing tyrosine or phenylalanine by high-tyrosine or high-phenylalanine chow feeding exacerbates HF phenotypes in transverse aortic constriction and isoproterenol infusion mice models. Knocking down phenylalanine dehydrogenase abolishes the effect of phenylalanine, indicating that phenylalanine functions by converting to tyrosine. Mechanistically, tyrosyl-tRNA synthetase (YARS) binds to ataxia telangiectasia and Rad3-related gene (ATR), catalyzes lysine tyrosylation (K-Tyr) of ATR, and activates the DNA damage response (DDR) in the nucleus. Increased tyrosine inhibits the nuclear localization of YARS, inhibits the ATR-mediated DDR, accumulates DNA damage, and elevates cardiomyocyte apoptosis. Enhancing ATR K-Tyr by overexpressing YARS, restricting tyrosine, or supplementing tyrosinol, a structural analog of tyrosine, promotes YARS nuclear localization and alleviates HF in mice. Our findings implicate facilitating YARS nuclear translocation as a potential preventive and/or interfering measure against HF.

Aspartame consumption during pregnancy impairs placenta growth in mice through sweet taste receptor-reactive oxygen species-dependent pathway

The prevalence of obesity has risen dramatically over recent years, and so has the prevalence of adverse obesity-associated pregnancy outcomes. To combat obesity, the calorie contents of many foods and beverages may be reduced by the use of artificial sweeteners, such as aspartame. However, animal studies suggest that aspartame and its metabolites may exhibit toxicity, and the effects of aspartame on pregnancy are largely unknown. In this study, we treated pregnant mice with aspartame by oral gavage and found that the treatment decreased fasting blood glucose level, whereas systolic blood pressure was elevated. Importantly, the aspartame-treated animals also had low placenta and fetus weights, as well as reduced thickness of the placenta decidua layer. Moreover, aspartame decreased the expression of epithelial-mesenchymal transition proteins and manganese superoxide dismutase (MnSOD) in mouse placentae. In order to clarify the mechanisms though which aspartame affects placenta, we performed experiments on 3A-sub-E trophoblasts. In the cells, aspartame treatments induced cell cycle arrest and reduced the proliferation rate, epithelial-mesenchymal transition, migration activity and invasion activity. We also found that aspartame increased reactive oxygen species (ROS) levels to hyper-activate Akt and downregulate MnSOD expression. Pretreatment with antioxidants or sweet taste receptor inhibitors reversed the effects of aspartame on trophoblast function. We also found that the aspartame metabolite phenylalanine similarly induced ROS production and affected proliferation of trophoblasts. Taken together, our data suggest that aspartame consumption during pregnancy may impact the structure, growth and function of the placenta via sweet taste receptor-mediated stimulation of oxidative stress.

Higher dietary intake of aromatic amino acids was associated with lower risk of cardiovascular disease mortality in adult participants in NHANES III

Little is known about the associations between dietary aromatic amino acids (AAAs) intake and mortality from all causes and cardiovascular disease (CVD). Accordingly, we evaluated these associations in the adult population of the United States using data from the Third National Health and Nutrition Examination Survey. This was a cohort study. Dietary intake of AAAs (tyrosine, phenylalanine, and tryptophan) was determined from the total nutrient intake document. We hypothesized that higher dietary AAA intake would lower all-cause and CVD mortality in adults in the United States. First, we categorized participants into quintiles based on their dietary intakes of total AAAs, tyrosine, phenylalanine, and tryptophan. Then, we established 4 Cox proportional-hazards models (models 1-4) and calculated hazard ratios and 95% confidence intervals to estimate the associations between dietary intakes of total AAAs, tyrosine, phenylalanine, and tryptophan and all-cause and CVD mortality. Mortality status was primarily obtained from files linked to the National Death Index records up to December 31, 2015. After multivariate adjustment, the hazard ratios (95% confidence intervals) of CVD mortality in the highest quintiles of dietary total AAAs, tyrosine, phenylalanine, and tryptophan intake (reference: the lowest quintiles) were 0.66 (0.52-0.84), 0.65 (0.51-0.83), 0.66 (0.52-0.85) and 0.64 (0.50-0.82), respectively. In a nationally representative cohort, higher dietary intakes of total AAA and the 3 individual AAAs were independently associated with a lower risk of CVD mortality, and these associations were stronger in non-Hispanic White people than in other people.

The association between dietary amino acids and the risk of nonalcoholic fatty liver disease among Tehranian adults: a case-control study

BACKGROUND

Amino acids (AAs) are important bioactive components in the diet that can be involved in various underlying biological processes that contribute to the development of nonalcoholic fatty liver disease (NAFLD). The present study investigates the association between dietary intake of amino acids and NAFLD in Iranian adults.

METHODS

This study was conducted among 225 newly diagnosed cases of NAFLD and 450 controls. A valid and reliable 168-item semiquantitative food frequency questionnaire (FFQ) was used to collect participants' dietary intakes. Multivariable logistic regression models were used to assess the association between tertiles of branched-chain amino acids (BCAAs), aromatic amino acids (AAAs), and sulfuric amino acids (SAAs) intake with the odds of NAFLD among the study participants.

RESULTS

The mean ± standard deviation of age and BMI of participants (53% male) were 38.1 ± 8.8 years and 26.8 ± 4.3 kg/m2, respectively. In the final models, the OR and 95% CI of NAFLD among participants in the highest tertiles of BCAAs, AAAs, and SAAs intake compared with those in the lowest tertiles were (OR = 2.82; 95% CI: 1.50-5.30), (OR = 2.82; 95% CI: 1.50-5.30), (OR = 2.86; 95% CI: 1.49-5.48), respectively.

CONCLUSION

Our study indicated a direct association between the intake of AAs groups, including BCAAs, AAAs, SAAs, and the odds of NAFLD. We suggest that other researchers examine the association between AAs groups and NAFLD in large cohort studies.

The causal associations of circulating amino acids with blood pressure: a Mendelian randomization study

BACKGROUND

Circulating levels of amino acids were associated with blood pressure (BP) in observational studies. However, the causation of such associations has been hypothesized but is difficult to prove in human studies. Here, we aimed to use two-sample Mendelian randomization analyses to evaluate the potential causal associations of circulating levels of amino acids with BP and risk of hypertension.

METHODS

We generated genetic instruments for circulating levels of nine amino acids by conducting meta-analyses of genome-wide association study (GWAS) in UK Biobank participants with metabolomic data (n = 98,317) and another published metabolomics GWAS (n = 24,925). Data on the associations of the genetic variants with BP and hypertension were obtained in the UK Biobank participants without metabolomic data (n = 286,390). The causal effects were estimated using inverse-variance weighted method.

RESULTS

Significant evidence consistently supported the causal effects of increased branched-chain amino acids (BCAAs, i.e., leucine, isoleucine, and valine) levels on higher BP and risk of hypertension (all P < 0.006 after Bonferroni correction except for Pleucine-on-diastolicBP = 0.008). For example, per standard deviation higher of genetically predicted isoleucine levels were associated with 2.71 ± 0.78 mmHg higher systolic BP and 1.24 ± 0.34 mmHg higher diastolic BP, as well as with 7% higher risk of hypertension (odds ratio: 1.07, [95% CI: 1.04-1.10]). In addition, per standard deviation higher of genetically predicted glycine level was associated with lower systolic BP (- 0.70 ± 0.17 mmHg, P = 4.04 × 10-5) and a lower risk of hypertension (0.99 [0.98-0.99], P = 6.46 × 10-5). In the reverse direction, genetically predicted higher systolic BP was associated with lower circulating levels of glycine (- 0.025±0.008, P = 0.001).

CONCLUSIONS

This study provides evidence for causal impacts of genetically predicted circulating BCAAs and glycine levels on BP. Meanwhile, genetically predicted higher BP was associated with lower glycine levels. Further investigations are warranted to clarify the underlying mechanisms.

Aromatic Amino Acids: Phenylalanine and Tyrosine in Patients with Hypertension and Coronary Artery Disease

Aim. To evaluate changes in the profile of aromatic amino acids (AAA) in patients with cardiovascular diseases (CVD): hypertension and coronary artery disease (CАD) in comparison with healthy study participants.

Material and methods. One hundred and thirty-one participants were included in the study: 58 participants were included in the hypertension group, 46 in the CАD group, and 27 participants without signs of CVD in the control group. We used ultrahigh-performance liquid chromatography in combination with a triple quadrupole analyzer to measure plasma AAA: phenylalanine and tyrosine (Phe, Tyr) in all study participants. The association of AAA with biochemical blood test parameters, echocardiography (EchoCG) parameters, blood pressure level and clinical characteristics was analyzed.

Results. A statistically significant difference in the level of concentration of Phe and Tyr was revealed (p=0,002 and p=0,024, respectively), comparing the three groups. Post-hoc analysis showed differences in the circulating level of both amino acids in patients with CAD vs the control group (Phe p=0,008 and Tyr p=0,020). Also a statistically significant difference in the level of Phe of the hypertension and CАD groups (p=0,017) was found. A negative correlation of low-density lipoproteins (LDL) with the level of Phe (r=-0,685, p<0,05) and Tyr (r=-0,583, p<0,05), as well as the level of Phe with total cholesterol (r=-0,461, p<0,05) was found in the group without CVD. In the hypertension group, only a weak positive correlation was found between very low-density lipoproteins and AAA levels (Phe r=0,326 and Tyr r=0,365, p<0,05), while in patients with CAD, the level of Phe and Tyr was negative correlated with high-density lipoprotein (r=-0,378 and r=-0,543, respectively, p<0,05), and the level of Tyr with LDL (r=0,349, p<0,05). When isolating the group with proven atherosclerosis of peripheral and/or coronary arteries, a statistically significant difference was revealed between the group of patients with CVD and clinical and instrumental signs of atherosclerosis and the group of patients with CVD without proven atherosclerosis in Phe level (p=0,019).

Conclusion. Concentrations of AAA were higher in patients with CVD, comparing with the control group. At the same time, an increase of the Phe level was associated with the presence of peripheral or coronary atherosclerosis. The revealed correlations of AAA with EchoCG parameters and lipid spectrum parameters require further study to understand the involvement of AAA in pathogenesis of CVD and its potential role as treatment target.

Metabolomic characteristics of spontaneously hypertensive rats under chronic stress and the treatment effect of Danzhi Xiaoyao Powder, a traditional Chinese medicine formula

OBJECTIVE

Numerous studies have demonstrated the close relationship between chronic stress and blood pressure (BP). Hypertensive subjects exhibit exaggerated reactions to stress, especially higher BP. The mechanisms by which stress affects pre-existing hypertension still need to be explored. Danzhi Xiaoyao Powder (DP), a historical traditional Chinese medicine formula, is a promising treatment for BP control in hypertensive patients under stress. The present study investigated the metabolomic disruption caused by chronic stress and the treatment effect and mechanism of DP.

METHODS

Spontaneously hypertensive rats (SHRs) were subjected to chronic restraint stress (CRS) for 4 weeks. BP was measured via the tail-cuff method, and anxiety-like behavior was quantified using the elevated-plus-maze test. Meanwhile, DP was administered intragastrically, and its effects were observed. Global metabolomic analysis was performed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, followed by multivariate statistical analysis to detect differential metabolites and pathways.

RESULTS

DP alleviated the CRS-induced increase in BP and anxiety-like behavior. Systematic metabolic differences were found among the three study groups. A total of 29 differential plasma metabolites were identified in both positive- and negative-ion modes. These metabolites were involved in triglyceride metabolism, amino acid (phenylalanine, tryptophan, and glycine) metabolism, and steroid hormone pathways.

CONCLUSION

These findings expose the metabolomic disturbances induced by chronic stress in SHRs and suggest an innovative treatment for this disorder.

Potential Antihypertensive Mechanisms of the Egg White-Derived Peptide QIGLF in Spontaneously Hypertensive Rats Revealed Using Untargeted Serum Metabolomics

The angiotensin-converting enzyme (ACE) inhibitory peptide QIGLF derived from egg white was shown to have significant in vivo antihypertensive effects in our previous study, but the intervention mechanisms at the metabolic level are still unclear. The UPLC-QTOF/MS-based untargeted metabolomics approach was used to clarify the potential antihypertensive mechanisms of QIGLF in the serum of spontaneously hypertensive rats (SHRs). Multivariate statistical analysis showed a clear difference in the metabolite profiles between the QIGLF and model groups. The results suggested that eight potential biomarkers were identified, that is, adrenic acid, ursodeoxycholic acid, glycocholic acid, taurocholic acid, tryptophan, acetylindoxyl, tyrosine, and 2-phenylethanol, which were mainly involved in aromatic amino acid biosynthesis and metabolism, biosynthesis of bile acid, and biosynthesis of unsaturated fatty acids. QIGLF might exert antihypertensive effects by improving endothelial dysfunction. This study provides a theoretical basis for future research and application of ACE inhibitory peptides in the prevention and improvement of hypertension.

How Perturbated Metabolites in Diabetes Mellitus Affect the Pathogenesis of Hypertension?

The presence of hypertension (HTN) in type 2 diabetes mellitus (DM) is a common phenomenon in more than half of the diabetic patients. Since HTN constitutes a predictor of vascular complications and cardiovascular disease in type 2 DM patients, it is of significance to understand the molecular and cellular mechanisms of type 2 DM binding to HTN. This review attempts to understand the mechanism via the perspective of the metabolites. It reviewed the metabolic perturbations, the biological function of perturbated metabolites in two diseases, and the mechanism underlying metabolic perturbation that contributed to the connection of type 2 DM and HTN. DM-associated metabolic perturbations may be involved in the pathogenesis of HTN potentially in insulin, angiotensin II, sympathetic nervous system, and the energy reprogramming to address how perturbated metabolites in type 2 DM affect the pathogenesis of HTN. The recent integration of the metabolism field with microbiology and immunology may provide a wider perspective. Metabolism affects immune function and supports immune cell differentiation by the switch of energy. The diverse metabolites produced by bacteria modified the biological process in the inflammatory response of chronic metabolic diseases either. The rapidly evolving metabolomics has enabled to have a better understanding of the process of diseases, which is an important tool for providing some insight into the investigation of diseases mechanism. Metabolites served as direct modulators of biological processes were believed to assess the pathological mechanisms involved in diseases.

High-Throughput Untargeted Serum Metabolomics Analysis of Hyperuricemia Patients by UPLC-Q-TOF/MS

Hyperuricemia (HUA) as a metabolic disease is closely associated with metabolic disorders. The etiology and pathogenesis of HUA are not fully understood, so there is no radical cure so far. Metabolomics, a specialized study of endogenous small molecule substances, has become a powerful tool for metabolic pathway analysis of selected differential metabolites, which is helpful for initially revealing possible development mechanisms of various human diseases. Twenty HUA patients and 20 healthy individuals participated in the experiment, and ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was employed to investigate serum samples to find differential metabolites. The statistical techniques used were principal component analysis and orthogonal partial least-squares discriminant analysis. The differences in metabolomics results of samples after pretreatment with different solvents were compared, 38, 20, 26, 28, 33, 50, and 40 potential differential metabolites were found, respectively, in HUA patient samples, and each group involved different metabolic pathways. Repetitive metabolites were removed, 138 differential metabolites in HUA serum were integrated for analysis, and the human body was affected by 7 metabolic pathways of glycerophospholipid metabolism, sphingolipid metabolism, arachidonic acid metabolism, linoleic acid metabolism, phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and α-linolenic acid metabolism. In this work, the metabolomics approach based on UPLC-Q-TOF/MS was employed to investigate serum metabolic changes in HUA patients, 138 potential differential metabolites related to HUA were identified, which provided associations of lipids, amino acids, fatty acids, organic acids, and nucleosides profiles of HUA individuals. Metabolic pathways involved in glycerophospholipid metabolism, sphingolipid metabolism, arachidonic acid metabolism, linoleic acid metabolism, phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and a-linolenic acid metabolism shed light on the understanding of the etiology and pathogenesis process of HUA.

Dietary Amino Acid Patterns Are Associated With Incidence of Chronic Kidney Disease

OBJECTIVES

No findings are available regarding the association of the dietary amino acid (AA) intakes with the risk of chronic kidney disease (CKD) in adults. We aimed to assess the association between dietary AA patterns and incidence of CKD in adults.

DESIGN AND METHODS

This study was conducted within the framework of Tehran Lipid and Glucose Study on 4,233 adults, who were free of CKD at baseline (2009-2011) and were followed for 3.1 years (2011-2014). The principal component analysis was used based on 8 AA groups to characterize major AA patterns. Multivariable logistic regression models were used to estimate the risk of CKD across quartiles of dietary AA pattern scores.

RESULTS

Three major AA patterns were extracted: (1) higher loads of branched-chain, alcoholic, and aromatic AAs; (2) higher loads of acidic AAs, proline, and lower load of alkaline AAs and small AAs; and (3) higher loads of sulfuric AAs and small AAs. The mean ± standard deviation age of participants (45.9% male) was 39.4 ± 11.7 at baseline and the incidence of CKD was 12.1% (513 cases) after 3.1 years of follow-up. The highest score of first dietary AA pattern tended to be associated with an increased risk of CKD (odds ratio = 1.43, 95% confidence interval1.06-1.93); however, the second pattern was related to a decreased risk of CKD (odds ratio = 0.71, 95% confidence interval: 0.52-0.97) in the multivariable model.

CONCLUSION

These novel findings suggest that the dietary AA patterns may modify risk of CKD.

AHR canonical pathway: in vivo findings to support novel antihypertensive strategies

Essential hypertension (HTN) is a disease where genetic and environmental factors interact to produce a high prevalent set of almost indistinguishable phenotypes. The weak definition of what is under the umbrella of HTN is a consequence of the lack of knowledge on the players involved in environment-gene interaction and their impact on blood pressure (BP) and mechanisms. The disclosure of these mechanisms that sense and (mal)adapt to toxic-environmental stimuli might at least determine some phenotypes of essential HTN and will have important therapeutic implications. In the present manuscript, we looked closer to the environmental sensor aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor involved in cardiovascular physiology, but better known by its involvement in biotransformation of xenobiotics through its canonical pathway. This review aims to disclose the contribution of the AHR-canonical pathway to HTN. For better mirror the complexity of the mechanisms involved in BP regulation, we privileged evidence from in vivo studies. Here we ascertained the level of available evidence and a comprehensive characterization of the AHR-related phenotype of HTN. We reviewed clinical and rodent studies on AHR-HTN genetic association and on AHR ligands and their impact on BP. We concluded that AHR is a druggable mechanistic linker of environmental exposure to HTN. We conclude that is worth to investigate the canonical pathway of AHR and the expression/polymorphisms of its related genes and/or other biomarkers (e.g. tryptophan-related ligands), in order to identify patients that may benefit from an AHR-centered antihypertensive treatment.

Association Between Blood Pressure and Branched-Chain/Aromatic Amino Acid Excretion Rate in 24-Hour Urine Samples from Elderly Hypertension Patients

BACKGROUND

Recently, the association between lifestyle-related diseases and free amino acids in the blood plasma-especially branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs)-has been highlighted. However, few studies have been carried out on 24-hour urine samples. Therefore, we aimed to explore the relationships between 24-hour urinary BCAAs and AAAs excretion rate and blood pressure (BP) in elderly patients with hypertension.

METHODS AND RESULTS

Each of the 322 elderly patients with hypertension completed an in-person questionnaire interview, underwent a physical examination, and provided a 24-hour urine specimen. We measured their BCAAs and AAAs excretion rate, and used multiple linear regression analysis with variable selection to construct models describing the relationships between their BCAAs and AAAs excretion rate and BP. After adjusted for age, gender, height, and weight, valine was inversely associated with both systolic blood pressure (SBP) (β: -0.232, 95% CI: -0.16, -0.006) and diastolic blood pressure (DBP) (β: -0.144, 95% CI: -0.089, -0.005). These findings were invariant even following adjustment for urine volume and drugs history, and Ile was positively associated with DBP (β: 0.170, 95% CI: 0.001, 0.066).

CONCLUSION

The data revealed that the excretion rate of 24-hour urinary BCAAs was closely related to BP in elderly hypertension patients, and these findings will provide new insights into the association between BACC metabolism and BP.

Study of the Mechanism Underlying the Antihypertensive Effects of Eucommia ulmoides and Tribulus terrestris Based on an Analysis of the Intestinal Microbiota and Metabonomics

The combination of Eucommia ulmoides and Tribulus terrestris (ET) has been widely utilized in clinical practice for thousands of years, but the mechanism underlying its efficacy has not been elucidated to date. This study attempted to investigate the role played by the intestinal microbiota and fecal metabolism in the response of elderly spontaneous hypertensive rats (SHRs) to ET administration as a treatment for hypertension. Fourteen male spontaneously hypertensive rats (SHRs, 18 months old) were randomly divided into an ET group and an SHR group, and 7 Wistar-Kyoto (WKY) rats of the same age were employed as the control group. The ET group was intragastrically administered 1.0 g/kg/d ET for 42 days, and SHRs and WKY rats were administered an equal amount of normal saline intragastrically. The intestinal microbiota and fecal metabolism were analyzed by 16S rRNA sequencing and the GC-MS (gas chromatography-mass spectrometry)/MS assay. ET treatment decreased blood pressure steadily, improved the colonic tissue morphology, and changed the structure and composition of the imbalanced microbiota in SHRs. Specifically, ET treatment increased the abundance of Eubacterium, which might be one of the target microbes for ET, and had a negative correlation with the levels of α-tocopherol, chenodeoxycholic acid, and deoxycholic acid according to the Spearman correlation analysis. The change in the intestinal microbiota affected the fecal metabolic pattern of SHRs. Eight potential biomarkers were determined to be primarily enriched in ABC transporters, phenylalanine metabolism, central carbon metabolism in cancer, purine metabolism, and protein digestion and absorption. The correlation analysis demonstrated that the abundance of Eubacterium and the decreased levels of α-tocopherol, chenodeoxycholic acid, and deoxycholic acid in the ET group were highly correlated. Our results suggest that ET has a good antihypertensive effect, which may be driven by the intestinal microbiota and their beneficial metabolites. The results of this study may help to elucidate the antihypertensive mechanism of ET.

Phenylalanine induces pulmonary hypertension through calcium-sensing receptor activation

Phenylalanine levels are associated with pulmonary hypertension in metabolic profiling clinical studies. However, the pathophysiological role of phenylalanine on pulmonary circulation is still unclear. We experimentally addressed the direct impact of phenylalanine on pulmonary circulation in rats and explored the underlying molecular pathway. Phenylalanine was injected intraperitoneally into Sprague-Dawley rats (400 mg/100 g body wt) as a single dose or daily in a chronic manner for 2, 3, and 4 wk. Chronic injection of phenylalanine induced pulmonary hypertension with time-dependent severity, evidenced by elevated pulmonary artery pressure and pulmonary vascular resistance as well as pulmonary artery and right ventricular hypertrophy. Using tandem mass spectrometry analysis, we found a quick twofold increase in blood level of phenylalanine 2 h following injection. This increase led to a significant accumulation of phenylalanine in lung after 4 h, which remained sustained at up to a threefold increase after 4 wk. In addition, a cellular thermal shift assay with lung tissues from phenylalanine-injected rats revealed the binding of phenylalanine to the calcium-sensing receptor (CaSR). In vitro experiments with cultured pulmonary arterial smooth muscle cells showed that phenylalanine activated CaSR, as indicated by an increase in intracellular calcium content, which was attenuated or diminished by the inhibition or knockdown of CaSR. Finally, the global knockout or lung-specific knockdown of CaSR significantly attenuated phenylalanine-induced pulmonary hypertension. Chronic phenylalanine injection induces pulmonary hypertension through binding to CaSR and its subsequent activation. Here, we demonstrate a pathophysiological role of phenylalanine in pulmonary hypertension through the CaSR. This study provides a novel animal model for pulmonary hypertension and reveals a potentially clinically significant role for this metabolite in human pulmonary hypertension as a marker, a mediator of disease, and a possible therapeutic target.

Amino Acids in Health and Endocrine Function

Dietary amino acids play an important role in maintaining health. Branched chain amino acids can adversely increase blood pressure whereas arginine and citrulline can reduce it. D-amino acids play important roles in several cell types including testis, the nervous system and adrenal glands. Several amino acids also can have dramatic effects on diabetes; branched chain amino acids, phenylalanine and tyrosine have been implicated while others, namely arginine and citrulline can improve outcomes. Leucine has been shown to play important roles in muscle primarily through the mTOR pathway though this effect does not translate across every population. Glutamine, arginine and D-aspartate also exert their muscle effects through mTOR. Relationships between amino acids and endocrine function include that of glucocorticoids, thyroid function, glucagon-like peptide 1 (GLP-1), ghrelin, insulin-like growth factor-1 (IGF-1) and leptin. Leucine, for example, can alleviate the effect of dexamethasone on muscle protein accretion. Interestingly, amino acid transporters play an important role in thyroid function. Several amino acids have been shown to increase GLP-1 levels in non-diabetics when administered orally. Similarly, several amino acids increase ghrelin levels in different species while cysteine can decrease it in mice. There is evidence to suggest that the arginine/NO pathway may be involved in modulating some of the effects of ghrelin on cells. In regard to IGF-1, branched chain amino acids can increase levels in adults while tryptophan and phenylalanine have been shown to increase levels in infants. Finally, leptin levels can be elevated by branched chain amino acids while restricting leucine in high fat diets can increase leptin sensitivity.

Amino Acids and Developmental Origins of Hypertension

During pregnancy, amino acids are important biomolecules that play essential roles in fetal growth and development. Imbalanced amino acid intake during gestation may produce long-term morphological or functional changes in offspring, for example, developmental programming that increases the risk of developing hypertension in later life. Conversely, supplementation with specific amino acids could reverse the programming processes in early life, which may counteract the rising epidemic of hypertension. This review provides an overview of the evidence supporting the importance of amino acids during pregnancy and fetal development, the impact of amino acids on blood pressure regulation, insight from animal models in which amino acids were used to prevent hypertension of developmental origin, and interactions between amino acids and the common mechanisms underlying development programming of hypertension. A better understanding of the pathophysiological roles of specific amino acids and their interactions in developmental programming of hypertension is essential so that pregnant mothers are able to benefit from accurate amino acid supplementation during pregnancy in order to prevent hypertension development in their children.

Diurnal Timing Dependent Alterations in Gut Microbial Composition Are Synchronously Linked to Salt-Sensitive Hypertension and Renal Damage

Alterations of diurnal rhythms of blood pressure (BP) and reshaping of gut microbiota are both independently associated with hypertension. However, the relationships between biorhythms of BP and gut microbial composition are unknown. We hypothesized that diurnal timing-associated alterations of microbial compositions are synchronous with diurnal rhythmicity, dip in BP, and renal function. To test this hypothesis, Dahl salt-sensitive (S) rats on low- and high-salt diets were examined for time of day effects on gut microbiota, BP, and indicators of renal damage. Major shifts in night and day patterns of specific groups of microbiota were observed between the dark (active) and light (rest) phases, which correlated with diurnal rhythmicity of BP. The diurnal abundance of Firmicutes, Bacteroidetes, and Actinobacteria were independently associated with BP. Discrete bacterial taxa were observed to correlate independently or interactively with one or more of the following 3 factors: (1) BP rhythm, (2) dietary salt, and (3) dip in BP. Phylogenetic Investigation of Communities revealed diurnal timing effects on microbial pathways, characterized by upregulated biosynthetic processes during the active phase of host, and upregulated degradation pathways of metabolites in the resting phase. Additional metagenomics functional pathways with rhythm variations were noted for aromatic amino acid metabolism and taurine metabolism. These diurnal timing dependent changes in microbiota, their functional pathways, and BP dip were associated with concerted effects of the levels of renal lipocalin 2 and kidney injury molecule-1 expression. These data provide evidence for a firm and concerted diurnal timing effects of BP, renal damage, and select microbial communities.

Nutrient patterns and cardiometabolic risk factors among Iranian adults: Tehran lipid and glucose study

Background

The present study aimed to assess the relation between nutrient patterns and changes in adult anthropometric and cardiometabolic factors.

Methods

This study was conducted on 1637 adults participating in the Tehran Lipid and Glucose Study (2005–2008), who were free of cardiovascular diseases and cancer and had completed dietary data. They were followed to the next survey (2008–2011). Dietary intakes were collected and nutrient patterns were obtained. Three year changes in anthropometric and cardiometabolic factors were measured.

Results

Five nutrient patterns were extracted. The first pattern was characterized by “plant protein, thiamine, niacin, and minerals including phosphorus, zinc, copper, magnesium, manganese, and selenium”. Animal protein, lactose, vitamin D, riboflavine, pantothenic acid, vitamin B12, calcium, phosphorus, and zinc" were loaded in the second pattern. The third and fourth patterns were characterized by “vitamin K, fiber, calcium, iron, manganese, and potassium”, and “high correlation with starch, thiamine and folate, and negative correlation with mono and poly unsaturated fatty acids and vitamin E”, respectively. The fifth pattern was high in Fructose, vitamins A, C, pyridoxine, and potassium. There was no association between nutrient patterns and 3-year changes in blood pressure and fasting blood glucose; whereas, per each quartile increment of the fifth pattern adjusted for potential confounders, triglyceride change was decreased [β = − 3.66, 95% CI (− 6.57, − 0.57); P for trend = 0.014].

Conclusion

Present study indicates that nutrient patterns may have an association with cardiometabolic factors, particularly a pattern rich in fructose, vitamins A, C, pyridoxine, and potassium which decreases triglyceride level.

Amino Acids and Hypertension in Adults

Accumulating evidence suggests a potential role of dietary protein among nutritional factors interfering with the regulation of blood pressure. Dietary protein source (plant versus animal protein), and especially, protein composition in terms of amino acids has been postulated to interfere with mechanisms underlying the development of hypertension. Recently, mounting interest has been directed at amino acids in hypertension focusing on habitual dietary intake and their circulating levels regardless of single amino acid dietary supplementation. The aim of the present review was to summarize epidemiological evidence concerning the connection between amino acids and hypertension. Due to the large variability in methodologies used for assessing amino acid levels and heterogeneity in the results obtained, it was not possible to draw robust conclusions. Indeed, some classes of amino acids or individual amino acids showed non-causative association with blood pressure as well as the incidence of hypertension, but the evidence was far from being conclusive. Further research should be prompted for a thorough understanding of amino acid effects and synergistic actions of different amino acid classes on blood pressure regulation.