Metabolomic Insights on Potassium Excretion, Blood Pressure, and Glucose Homeostasis: The African-PREDICT Study.

BACKGROUND: Low-potassium intake is associated with a higher risk of type 2 diabetes and hypertension. Both conditions occur more frequently in Black populations, who also consume less potassium-rich foods. OBJECTIVES: Using metabolomics to identify dysregulated metabolic pathways associated with low-potassium excretion may procure more accurate entry points for nutritional prevention and intervention for type 2 diabetes and hypertension. METHODS: A total of 440 White and 350 Black adults from the African-PREDICT study (aged 20-30 y) were included. Twenty-four-hour blood pressure (BP) was measured. Potassium, sodium, and fasting glucose concentrations were analyzed in 24-h urine and plasma samples. Liquid chromatography-tandem mass spectrometry-based metabolomics included the analyses of amino acids and acylcarnitines in spot urine samples. RESULTS: Black participants had lower urinary potassium concentrations than Whites (36.6 compared with 51.1 mmol/d; P < 0.001). In White but not Black adults, urinary potassium correlated positively with 2-aminoadipic acid (2-AAA) (r = 0.176), C3-[propionyl]carnitine (r = 0.137), C4-[butyryl]carnitine (r = 0.169) and C5-[isovaleryl]carnitine (r = 0.167) in unadjusted and 2-AAA (r = 0.158) and C4-carnitine (r = 0.160) in adjusted analyses (all P < 0.05 and q < 0.05). Elevated C0-, C3-, and C5-carnitine in turn were positively associated with systolic BP (Black and White groups), diastolic BP (Black group), and glucose (White group) (all P < 0.05). CONCLUSIONS: Racial differences are an important consideration when investigating nutrient-metabolite relationships and the role thereof in cardiovascular disease. Only in White adults did urinary potassium associate with 2-AAA and short-chain acylcarnitines. These metabolites were positively related to BP and fasting plasma glucose concentrations. In White adults, the metabolomic profiles related to potassium excretion may contribute to BP regulation and glucose homeostasis. This trial was registered at clinicaltrials.gov as NCT03292094.

A ketogenic diet alters mTOR activity, systemic metabolism and potentially prevents collagen degradation associated with chronic alcohol consumption in mice.

INTRODUCTION: A ketogenic diet (KD), which is a high fat, low carbohydrate diet has been shown to inhibit the mammalian target of rapamycin (mTOR) pathway and alter the redox state. Inhibition of the mTOR complex has been associated with the attenuation and alleviation of various metabolic and- inflammatory diseases such as neurodegeneration, diabetes, and metabolic syndrome. Various metabolic pathways and signalling mechanisms have been explored to assess the therapeutic potential of mTOR inhibition. However, chronic alcohol consumption has also been reported to alter mTOR activity, the cellular redox- and inflammatory state. Thus, a relevant question that remains is what effect chronic alcohol consumption would have on mTOR activity and overall metabolism during a KD-based intervention. OBJECTIVES: The aim of this study was to evaluate the effect of alcohol and a KD on the phosphorylation of the mTORC1 target p70S6K, systemic metabolism as well as the redox- and inflammatory state in a mouse model. METHODS: Mice were fed either a control diet with/without alcohol or a KD with/without alcohol for three weeks. After the dietary intervention, samples were collected and subjected towards western blot analysis, multi-platform metabolomics analysis and flow cytometry. RESULTS: Mice fed a KD exhibited significant mTOR inhibition and reduction in growth rate. Alcohol consumption alone did not markedly alter mTOR activity or growth rate but moderately increased mTOR inhibition in mice fed a KD. In addition, metabolic profiling showed alteration of several metabolic pathways as well as the redox state following consumption of a KD and alcohol. A KD was also observed to potentially prevent bone loss and collagen degradation associated with chronic alcohol consumption, as indicated by hydroxyproline metabolism. CONCLUSION: This study sheds light on the influence that a KD alongside alcohol intake can exert on not just mTOR, but also their effect on metabolic reprogramming and the redox state.

Markers of arterial stiffness and urinary metabolomics in young adults with early cardiovascular risk: the African-PREDICT study.

INTRODUCTION: Increased exposure to risk factors in the young and healthy contributes to arterial changes, which may be accompanied by an altered metabolism. OBJECTIVES: To increase our understanding of early metabolic alterations and how they associate with markers of arterial stiffness, we profiled urinary metabolites in young adults with cardiovascular disease (CVD) risk factor(s) and in a control group without CVD risk factors. METHODS: We included healthy black and white women and men (N = 1202), aged 20-30 years with a detailed CVD risk factor profile, reflecting obesity, physical inactivity, smoking, excessive alcohol intake, masked hypertension, hyperglycemia, dyslipidemia and low socio-economic status, forming the CVD risk group (N = 1036) and the control group (N = 166). Markers of arterial stiffness, central systolic blood pressure (BP) and pulse wave velocity were measured. A targeted metabolomics approach was followed by measuring amino acids and acylcarnitines using a liquid chromatography-tandem mass spectrometry method. RESULTS: In the CVD risk group, central systolic BP (adjusted for age, sex, ethnicity) was negatively associated with histidine, arginine, asparagine, serine, glutamine, dimethylglycine, threonine, GABA, proline, methionine, pyroglutamic acid, aspartic acid, glutamic acid, branched chain amino acids (BCAAs) and butyrylcarnitine (all P ≤ 0.048). In the same group, pulse wave velocity (adjusted for age, sex, ethnicity, mean arterial pressure) was negatively associated with histidine, lysine, threonine, 2-aminoadipic acid, BCAAs and aromatic amino acids (AAAs) (all P ≤ 0.044). In the control group, central systolic BP was negatively associated with pyroglutamic acid, glutamic acid and dodecanoylcarnitine (all P ≤ 0.033). CONCLUSION: In a group with increased CVD risk, markers of arterial stiffness were negatively associated with metabolites related to AAA and BCAA as well as energy metabolism and oxidative stress. Our findings may suggest that metabolic adaptations may be at play in response to increased CVD risk to maintain cardiovascular integrity.

Early vascular ageing phenotypes and urinary targeted metabolomics in children and young adults: the ExAMIN Youth SA and African-PREDICT studies.

Some individuals are susceptible to accelerated biological ageing, resulting in premature alterations in arterial structure and function. Identifying early-onset vascular ageing characterised by arterial stiffening is vital for intervention and preventive strategies. We stratified and phenotyped healthy children (5-9 yrs) and young adults (20-30 yrs) into their vascular ageing extremes established by carotid-femoral pulse wave velocity (cfPWV) percentiles (i.e., healthy vascular ageing (HVA) and early vascular ageing (EVA)). We compared anthropometric, cardiovascular, and metabolomic profiles and explored associations between cfPWV and urinary metabolites. Children and adults in the EVA groups displayed higher levels of adiposity, cardiovascular, and lifestyle risk factors (adults only) (all p ≤ 0.018). In adults, several urinary metabolites were lower in the EVA group (all q ≤ 0.039) when compared to the HVA group, with no differences observed in children. In multiple regression analysis (adults only), we found inverse associations between cfPWV with histidine (adj. R2 = 0.038; ß = -0.192; p = 0.013) and beta-alanine (adj. R2 = 0.034; ß = -0.181; p = 0.019) in the EVA group, but with arginine (adj. R2 = 0.021; ß = -0.160; p = 0.024) in the HVA group. The inverse associations of beta-alanine and histidine with cfPWV in the EVA group is suggestive that asymptomatic young adults who present with an altered metabolomic and less desired cardiovascular profile in combination with unfavourable lifestyle behaviours may be predisposed to early-onset vascular ageing. Taken together, screening on both a phenotypic and metabolic level may prove important in the early detection, prevention, and intervention of advanced biological ageing.

Using urinary metabolomics to identify metabolic pathways linked to cardiac structural alterations in young adults: The African-PREDICT study.

BACKGROUND AND AIMS: Risk factor exposure from young ages was shown to contribute to cardiovascular events - cardiac hypertrophy, which may be accompanied by an altered metabolism. To determine how early metabolic alterations associate with myocardial structural changes, we profiled urinary metabolites in young adults with cardiovascular disease (CVD) risk factor(s) and a control group without CVD risk factors. METHODS AND RESULTS: We included healthy adults (N = 1202), aged 20-30 years, stratified based on risk factors, i.e., obesity, physical inactivity, elevated blood pressure (BP), hyperglycemia, dyslipidemia, low socio-economic status, smoking and excessive alcohol use - forming the CVD risk group (N = 1036) and the control group (N = 166). Relative wall thickness (RWT) and left ventricular mass index (LVMi) were measured using echocardiography. Targeted metabolomics data were obtained using a liquid chromatography-tandem mass spectrometry method. Clinic systolic BP, 24 h BP and RWT were higher in the CVD risk group compared to the control group (all P ≤ 0.031). Exclusively in the CVD risk group, RWT associated with creatine and dodecanoylcarnitine; while LVMi associated with glycine, serine, glutamine, threonine, alanine, citrulline, creatine, proline, pyroglutamic acid and glutamic acid (all P ≤ 0.040). Exclusively in the control group, LVMi associated with propionylcarnitine and butyrylcarnitine (all P ≤ 0.009). CONCLUSION: In young adults without CVD, but with CVD risk factors, LVMi and RWT associated with metabolites linked energy metabolism (shifting from solely fatty acid oxidation to glycolysis, with impaired creatine kinase activity) and oxidative stress. Our findings support early onset metabolic changes accompanying cardiac structural alterations due to lifestyle and behavioural risk factors.

Cross-comparison of systemic and tissue-specific metabolomes in a mouse model of Leigh syndrome.

INTRODUCTION: The value of metabolomics in multi-systemic mitochondrial disease research has been increasingly recognized, with the ability to investigate a variety of biofluids and tissues considered a particular advantage. Although minimally invasive biofluids are the generally favored sample type, it remains unknown whether systemic metabolomes provide a clear reflection of tissue-specific metabolic alterations. OBJECTIVES: Here we cross-compare urine and tissue-specific metabolomes in the Ndufs4 knockout mouse model of Leigh syndrome-a complex neurometabolic MD defined by progressive focal lesions in specific brain regions-to identify and evaluate the extent of common and unique metabolic alterations on a systemic and brain regional level. METHODS: Untargeted and semi-targeted multi-platform metabolomics were performed on urine, four brain regions, and two muscle types of Ndufs4 KO (n≥19) vs wildtype (n≥20) mice. RESULTS: Widespread alterations were evident in alanine, aspartate, glutamate, and arginine metabolism in Ndufs4 KO mice; while brain-region specific metabolic signatures include the accumulation of branched-chain amino acids, proline, and glycolytic intermediates. Furthermore, we describe a systemic dysregulation in one-carbon metabolism and the tricarboxylic acid cycle, which was not clearly reflected in the Ndufs4 KO brain. CONCLUSION: Our results confirm the value of urinary metabolomics when evaluating MD-associated metabolites, while cautioning against mechanistic studies relying solely on systemic biofluids.

One mutation, three phenotypes: novel metabolic insights on MELAS, MIDD and myopathy caused by the m.3243A > G mutation.

INTRODUCTION: The m.3243A > G mitochondrial DNA mutation is one of the most common mitochondrial disease-causing mutations, with a carrier rate as high as 1:400. This point mutation affects the MT-TL1 gene, ultimately affecting the oxidative phosphorylation system and the cell's energy production. Strikingly, the m.3243A > G mutation is associated with different phenotypes, including mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), maternally inherited diabetes and deafness (MIDD) and myopathy. OBJECTIVES: We investigated urine metabolomes of MELAS, MIDD and myopathy patients in order to identify affected metabolic pathways and possible treatment options. METHODS: A multiplatform metabolomics approach was used to comprehensively analyze the metabolome and compare metabolic profiles of different phenotypes caused by the m.3243A > G mutation. Our analytical array consisted of NMR spectroscopy, LC-MS/MS and GC-TOF-MS. RESULTS: The investigation revealed phenotypic specific metabolic perturbations, as well as metabolic similarities between the different phenotypes. We show that glucose metabolism is highly disturbed in the MIDD phenotype, but not in MELAS or myopathy, remodeled fatty acid oxidation is characteristic of the MELAS patients, while one-carbon metabolism is strongly modified in both MELAS and MIDD, but not in the myopathy group. Lastly we identified increased creatine in the urine of the myopathy patients, but not in MELAS or MIDD. CONCLUSION: We conclude by giving novel insight on the phenotypes of the m.3243A > G mutation from a metabolomics point of view. Directives are also given for future investigations that could lead to better treatment options for patients suffering from this debilitating disease.

Novel mitochondrial and cytosolic purification pipeline for compartment-specific metabolomics in mammalian disease model tissues.

INTRODUCTION: Mitochondria represent an important milieu for studying the pathogenesis of several major diseases. The need for organelle-level metabolic resolution exists, as mitochondrial/cytosolic metabolites are often diluted beyond detection limits in complex samples. Compartment-specific studies are still hindered by the lack of efficient, cost-effective fractioning methods-applicable to laboratories of all financial/analytical standing. OBJECTIVES: We established a novel mitochondrial/cytosolic purification pipeline for complimentary GC-TOF-MS and 1H-NMR metabolomics using robust, commercially available fractionation strategies. METHODS: Magnetic based mitochondria isolation kits (MACS) were adapted for this purpose, accompanied by cytosolic filtering. Yield was assessed through the percentage recovery of citrate synthase (CS; a mitochondrial marker), purity by immunoblotting against compartment-specific proteins and integrity interrogated through the respiratory coupling ratio (RCR). The effects of the kit-based buffers on MS/NMR analyses of pure metabolite standards were evaluated. Finally, biological applicability to mammalian disease models was shown using Ndufs4 mouse brain tissue. RESULTS: With minor modifications, MACS produced around 60% more mitochondria compared to a differential centrifugation method. Less than 15% of lysosomal LAMP-2 protein was found in the MACS isolates, confirming relative purity-while RCR's above 6 indicate sufficient mitochondrial integrity. The filtering approach effectively depleted mitochondria from the cytosolic fraction, as indicated by negligible Hsp60 and CS levels. Our GC-MS pilot yielded 60-70 features per fraction, while NMR analyses could quantify 6-10 of the most abundant compounds in each fraction. CONCLUSION: This study provides a simple and flexible solution for mitochondrial and cytosolic metabolomics in animal model tissues, towards large-scale application of such methodologies in disease research.

Left ventricular mass and urinary metabolomics in young black and white adults: The African-PREDICT study.

BACKGROUND AND AIMS: Increased left ventricular mass is an independent predictor for cardiovascular events, and shown to be higher in black than white populations. To gain a better understanding of early factors contributing to increased left ventricular mass in young black adults, we investigated metabolomic profiles, identified and compared metabolites that associated with left ventricular mass index in healthy black and white adults. METHODS AND RESULTS: We included normotensive black and white participants from the African-PREDICT study, with data on urinary metabolomics and echocardiography. Urinary metabolites were measured using three different analytical platforms. Univariate statistical analyses, including independent t-test (adjusted for multiple comparisons), effect size (d ≥ 0.3) and single regression analyses were used to identify metabolites. When comparing the black and white groups, the black group had higher central systolic blood pressure (p > 0.005), whereas left ventricular mass index was similar between the groups (p = 0.97). Three from a total of 192 metabolites were identified to be more abundant (p < 0.046) and inversely associated with left ventricular mass index in the black group only: hydroxyproline (ß = -0.22; p = 0.045), glycine (ß = -0.20; p = 0.049) and trimethylamine (ß = -0.21; p = 0.037). CONCLUSION: Higher urinary levels of hydroxyproline, glycine and trimethylamine were inversely associated with left ventricular mass index in the black adults only. Hydroxyproline and glycine are important in maintaining healthy collagen turnover and stability in the heart. Our results may reflect an increase in collagen biosynthesis and collagen deposition in the left ventricle due to higher central systolic blood pressure in the black population.

The dilemma of diagnosing coenzyme Q10 deficiency in muscle.

BACKGROUND: Coenzyme Q10 (CoQ10) is an important component of the mitochondrial respiratory chain (RC) and is critical for energy production. Although the prevalence of CoQ10 deficiency is still unknown, the general consensus is that the condition is under-diagnosed. The aim of this study was to retrospectively investigate CoQ10 deficiency in frozen muscle specimens in a cohort of ethnically diverse patients who received muscle biopsies for the investigation of a possible RC deficiency (RCD). METHODS: Muscle samples were homogenized whereby 600 ×g supernatants were used to analyze RC enzyme activities, followed by quantification of CoQ10 by stable isotope dilution liquid chromatography tandem mass spectrometry. The experimental group consisted of 156 patients of which 76 had enzymatically confirmed RCDs. To further assist in the diagnosis of CoQ10 deficiency in this cohort, we included sequencing of 18 selected nuclear genes involved with CoQ10 biogenesis in 26 patients with low CoQ10 concentration in muscle samples. RESULTS: Central 95% reference intervals (RI) were established for CoQ10 normalized to citrate synthase (CS) or protein. Nine patients were considered CoQ10 deficient when expressed against CS, while 12 were considered deficient when expressed against protein. In two of these patients the molecular genetic cause could be confirmed, of which one would not have been identified as CoQ10 deficient if expressed only against protein content. CONCLUSION: In this retrospective study, we report a central 95% reference interval for 600 ×g muscle supernatants prepared from frozen samples. The study reiterates the importance of including CoQ10 quantification as part of a diagnostic approach to study mitochondrial disease as it may complement respiratory chain enzyme assays with the possible identification of patients that may benefit from CoQ10 supplementation. However, the anomaly that only a few patients were identified as CoQ10 deficient against both markers (CS and protein), while the majority of patients where only CoQ10 deficient against one of the markers (and not the other), remains problematic. We therefore conclude from our data that, to prevent possibly not diagnosing a potential CoQ10 deficiency, the expression of CoQ10 levels in muscle on both CS as well as protein content should be considered.

Miniaturized 1H-NMR method for analyzing limited-quantity samples applied to a mouse model of Leigh disease.

INTRODUCTION: The analysis of limited-quantity samples remains a challenge associated with mouse models, especially for multi-platform metabolomics studies. Although inherently insensitive, the highly specific characteristics of nuclear magnetic resonance (NMR) spectroscopy make it an advantageous platform for global metabolite profiling, particularly in mitochondrial disease research. OBJECTIVES: Show method equivalency between a well-established standard operating protocol (SOP) and our novel miniaturized 1H-NMR method. METHOD: The miniaturized method was performed in a 2 mm NMR tube on a standard 500 MHz NMR spectrometer with a 5 mm triple-resonance inverse TXI probe at room temperature. RESULTS: Firstly, using synthetic urine spiked with low (50 µM), medium (250 µM) and high (500 µM) levels (n = 10) of nine standards, both the SOP and miniaturized method were shown to have acceptable precision (CV < 15%), relative accuracy (80-120%), and linearity (R2 > 0.95), except for taurine. Furthermore, statistical equivalence was shown using the two one-sided test. Secondly, pooled mouse quadriceps muscle extract was used to further confirm method equivalence (n = 3), as well as explore the analytical dynamics of this novel approach by analyzing more-concentrated versions of samples (up to 10× concentration) to expand identification of metabolites qualitatively, with quantitative linearity. Lastly, we demonstrate the new technique's application in a pilot metabolomics study using minute soleus muscle tissue from a mouse model of Leigh syndrome using Ndufs4 KO mice. CONCLUSION: We demonstrate method equivalency, supporting our novel miniaturized 1H-NMR method as a financially feasible alternative to cryoprobe technology-for limited-quantity biological samples in metabolomics studies that requires a volume one-tenth of the SOP.

Metabolic Alterations in Mothers Living with HIV and Their HIV-Exposed, Uninfected Infants.

HIV-exposed, uninfected (HEU) children present with suboptimal growth and a greater susceptibility to infection in early life when compared to HIV-unexposed, uninfected (HUU) children. The reasons for these findings are poorly understood. We used a metabolomics approach to investigate the metabolic differences between pregnant women living with HIV (PWLWH) and their HEU infants compared to the uninfected and unexposed controls. Untargeted metabolomic profiling was performed using 1H-NMR spectroscopy on maternal plasma at 28 weeks' gestation and infant plasma at birth, 6/10 weeks, and 6 months. PWLWH were older but, apart from a larger 28 week mid-upper-arm circumference, anthropometrically similar to the controls. At all the time points, HEU infants had a significantly reduced growth compared to HUU infants. PWLWH had lower plasma 3-hydroxybutyric acid, acetoacetic acid, and acetic acid levels. In infants at birth, threonine and myo-inositol levels were lower in the HEU group while formic acid levels were higher. At 6/10 weeks, betaine and tyrosine levels were lower in the HEU group. Finally, at six months, 3-hydroxyisobutyric acid levels were lower while glycine levels were higher in the HEU infants. The NMR analysis has provided preliminary information indicating differences between HEU and HUU infants' plasma metabolites involved in energy utilization, growth, and protection from infection.

Metabolic and glutathione redox markers associated with brain-derived neurotrophic factor in depressed african men and women: evidence for counterregulation?

BACKGROUND: Major depression is associated with evidence for metabolic and redox imbalance and also with reports of lower serum levels of brain-derived neurotrophic factor (BDNF). However, the relationship between these factors has not been well studied. METHODS: We studied the contribution of physiological risk factors to cardiometabolic health in 200 adult male and female black Africans, aged between 36 and 52 years, presenting with (n = 89) and without (n = 111) symptoms of depression. Specifically the association between serum BDNF and markers of basal metabolic and redox status in depressed versus nondepressed individuals were analyzed. RESULTS: BDNF and markers of redox and metabolic status were not associated with the symptoms of depression. Waist circumference, a metabolic risk factor, was positively associated with BDNF and accounts for 49% of the variance in BDNF in depressed men. Reduced and oxidized glutathione were positively and negatively correlated with BDNF in depressed women, respectively, with glutathione redox status accounting for 36-42% of the variance in BDNF. CONCLUSION: Selected metabolic and redox factors explained gender-specific variances in serum BDNF levels in depressed African men and women. Our findings suggest that changes in redox and metabolic status may represent counterregulation by BDNF or alternatively that BDNF may mediate undesirable redox and metabolic changes that are associated with the development of a mood disorder.

The contribution of the C-824T tyrosine hydroxylase polymorphism to the prevalence of hypertension in a South African cohort: the SABPA study.

The C-824T single nucleotide polymorphism in the promoter region of the tyrosine hydroxylase gene has been associated with hypertension. It is well documented that African South Africans exhibit a higher prevalence of hypertension than Caucasians. However, the possible role of this mutation on 24-hour ambulatory blood pressure (AMBP) has not been investigated in African South Africans. Blood samples of 409 South Africans were screened for the mutation. Ambulatory blood pressure and lifestyle factors were also measured. Africans had higher incidence of hypertension and higher occurrence of the mutation. However, the contribution of the tyrosine hydroxylase C-824T single nucleotide polymorphism to hypertension could not be confirmed in our cohort.

Phenylalanine metabolism and tetrahydrobiopterin bio-availability in COVID-19 and HIV.

Various metabolomics studies have reported increased phenylalanine serum concentrations in SARS-CoV-2 positive cases and have correlated increased phenylalanine with COVID-19 severity. In this study, we report similar results based upon metabolomics analysis of serum collected from a South African cohort of adults with confirmed COVID-19. The novelty of this study is the inclusion of HIV positive cases in the African context. We found that pre-existing HIV co-infection exacerbates the disruption of phenylalanine metabolism in COVID-19. What is lacking in literature is biological context and deeper understanding of perturbed phenylalanine metabolism in COVID-19. We delve deep into the metabolism of phenylalanine in COVID-19 and posit new insights for COVID-19 cases co-infected with HIV; namely, HIV-COVID-19 co-infected individuals do not have sufficient bioavailability of tetrahydrobiopterin (BH4). Hence, we identify BH4 as a potential supplement to alleviate/lessen COVID-19 symptoms.

Diagnostic applications and limitations for the use of cell-free fetal DNA (cffDNA) in animal husbandry and wildlife management.

In animal breeding, a species sex can influence the value of the animal. For example, in the horse breeding industry, mares are preferred as polo horses, while in wildlife breeding males with larger horns are more valuable. Therefore, the economic advantages of knowing the unborn fetus' sex are important to successful animal management. Ultrasonography is used to determine the sex of unborn fetuses, but this method places additional stress on the animal and require specialized equipment and expertise. Conversely, molecular-based sexing techniques require less invasive sampling and can determine sex more reliably. Although in humans, various studies have evaluated the use of cell-free fetal DNA (cffDNA) for prenatal sexing, very few animal studies have been published in this field. Several factors can affect the sensitivity of cffDNA-based sex determination, for example the gestational age. These factors are often not optimized and validated when establishing a protocol for prenatal sexing. In this review, we summarize the current literature on cffDNA in animals. We discuss the diagnostic applications and limitations in the use thereof in animal husbandry and wildlife management. Lastly, the feasibility of implementing diagnostic tests is evaluated and solutions are given to the current drawbacks of the technology.

Immune and Metabolic Alterations in Children with Perinatal HIV Exposure.

With the global rollout of mother-to-child prevention programs for women living with HIV, vertical transmission has been all but eliminated in many countries. However, the number of children who are exposed in utero to HIV and antiretroviral therapy (ART) is ever-increasing. These children who are HIV-exposed-but-uninfected (CHEU) are now well recognized as having persistent health disparities compared to children who are HIV-unexposed-and-uninfected (CHUU). Differences reported between these two groups include immune dysfunction and higher levels of inflammation, cognitive and metabolic abnormalities, as well as increased morbidity and mortality in CHEU. The reasons for these disparities remain largely unknown. The present review focuses on a proposed link between immunometabolic aberrations and clinical pathologies observed in the rapidly expanding CHEU population. By drawing attention, firstly, to the significance of the immune and metabolic alterations observed in these children, and secondly, the impact of their healthcare requirements, particularly in low- and middle-income countries, this review aims to sensitize healthcare workers and policymakers about the long-term risks of in utero exposure to HIV and ART.

Urinary metabolomics, dietary salt intake and blood pressure: the African-PREDICT study.

In Black populations excessive salt intake may exacerbate the genetic predisposition to hypertension and promote the early onset of cardiovascular disease. Ethnic differences in the interaction between sodium intake and the metabolome may play a part in hypertension and cardiovascular disease development. We determined (1) urinary amino acid and acylcarnitine profiles of young Black and White adults according to low, moderate, and high dietary salt intake, and (2) investigated the triad of salt intake, systolic blood pressure (SBP), and the associated metabolomics profile. This study included 447 White and 380 Black adults aged 20-30 years from the African-PREDICT study. Estimated salt intake was determined from 24-hour urinary sodium levels. Urinary amino acids and acylcarnitines were measured using liquid chromatography-tandem mass spectrometry. Black adults exhibited no significant differences in SBP, amino acids, or acylcarnitines across low (<5g/day), moderate (5-10g/day), and high (>10g/day) salt intake. White adults with a high salt intake had elevated SBP compared to those with low or moderate intakes (p < 0.001). Furthermore, gamma-aminobutyric acid (GABA) (q = 0.020), citrulline (q = 0.020), glutamic acid (q = 0.046), serine (q = 0.054) and proline (q = 0.054) were lowest in those with higher salt intake. Only in White and not Black adults did we observe inverse associations of clinic SBP with GABA (Adj. R2 = 0.34; Std. ß = -0.133; p = 0.003), serine (Adj. R2 = 0.33; Std. ß = -0.109; p = 0.014) and proline (Adj. R2 = 0.33; Std. ß = -0.109; p = 0.014). High salt intake in White, but not in black adults, were related to metabolomic changes and may contribute to pathophysiological mechanisms associated with increased BP.

Identifying a metabolomics profile associated with masked hypertension in two independent cohorts: Data from the African-PREDICT and SABPA studies.

Individuals with masked hypertension (MHT) have a greater risk of adverse cardiovascular outcomes than normotensive (NT) individuals. Exploring metabolomic differences between NT and MHT individuals may help provide a better understanding of the etiology of MHT. We analyzed data from 910 young participants (83% NT and 17% MHT) (mean age 24 ± 3 years) from the African-PREDICT and 210 older participants (63% NT and 37% MHT) from the SABPA (mean age 42 ± 9.6 years) studies. Clinic and ambulatory blood pressures (BPs) were used to define BP phenotypes. Urinary amino acids and acylcarnitines were measured using liquid chromatography time-of-flight mass spectrometry in SABPA and liquid chromatography tandem mass spectrometry in the African-PREDICT studies. In the SABPA study, amino acids (leucine/isoleucine, valine, methionine, phenylalanine), free carnitine (C0-carnitine), and acylcarnitines C3 (propionyl)-, C4 (butyryl)-carnitine and total acylcarnitine) were higher in MHT than NT adults. In the African-PREDICT study, C0- and C5-carnitines were higher in MHT individuals. With unadjusted analyses in NT adults from the SABPA study, ambulatory SBP correlated positively with only C3-carnitine. In MHT individuals, positive correlations of ambulatory SBP with leucine/isoleucine, valine, methionine, phenylalanine, C0-carnitine and C3-carnitine were evident (all p < 0.05). In the African-PREDICT study, ambulatory SBP correlated positively with C0-carnitine (r = 0.101; p = 0.006) and C5-carnitine (r = 0.195; p < 0.001) in NT adults and C5-carnitine in MHT individuals (r = 0.169; p = 0.034). We demonstrated differences between the metabolomic profiles of NT and MHT adults, which may reflect different stages in the alteration of branched-chain amino acid metabolism early on and later in life.

Urinary metabolomics profiling by cardiovascular risk factors in young adults: the African Prospective study on Early Detection and Identification of Cardiovascular disease and Hypertension study.

AIM: Risk factors contributes to a dysregulated metabolism and may ultimately increase the predisposition for cardiovascular disease (CVD) development. To increase our understanding of mechanistic pathways associated with CVD risk, we profiled the urinary metabolome according to individual and clusters of CVD risk factors in comparison with a control group without any risk factors. METHODS AND RESULTS: Healthy black and white women and men ( N  = 1202), aged 20-30 years with a detailed CVD risk factor profile were included. CVD risk groups: obese, physical inactive, smoking, excessive alcohol intake, masked hypertensive, hyperglycaemic, dyslipidemic and low socioeconomic status. CVD risk clusters were based on the presence of 1, 2 and 3 or more risk factors. Liquid chromatography-tandem mass spectrometry was used to obtain urinary metabolomics data (amino acids and acylcarnities). Compared with the control group, higher levels of metabolites associated with aromatic and branched chain amino acid metabolism including phenylalanine, tyrosine and leucine/isoleucine were found in the obese, masked hypertensive, hyperglycaemic, low socioeconomic groups (all q  ≤ 0.032) and 3+ CVD risk cluster (all P  ≤ 0.034). Metabolites associated with the y-glutamyl cycle including glycine, histidine, serine, glutamine, methionine, cystine and pyroglutamic acid were found in the hyperglycaemic, low socioeconomic groups (all q  ≤ 0.050), 2 and 3+ CVD risk clusters (all P  ≤ 0.041). Metabolites associated with energetics including acetylcarnitine (lower levels), hexanoylcarnitine and decanoylcarnitine were found in the low socioeconomic group, 1 and 3+ CVD risk clusters ( q / P  ≤ 0.050) ( ß -oxidation). In addition to the above-mentioned amino acids, alanine and threonine were found in the hyperglycaemic, low socioeconomic groups, 2 and 3+ CVD risk clusters (all q / P  ≤ 0.047) (glycolysis). Creatine in the obese, hyperglycaemic groups (all q  ≤ 0.049) and 3+ CVD risk cluster (all P  ≤ 0.041) (creatine pathway). CONCLUSION: Exposure to CVD risk factors is associated with a dysregulated metabolism in the above-mentioned pathways that may precede the development of CVD.