Longitudinal metabolic and gut bacterial profiling of pregnant women with previous bariatric surgery.

OBJECTIVE: Due to the global increase in obesity rates and success of bariatric surgery in weight reduction, an increasing number of women now present pregnant with a previous bariatric procedure. This study investigates the extent of bariatric-associated metabolic and gut microbial alterations during pregnancy and their impact on fetal development. DESIGN: A parallel metabonomic (molecular phenotyping based on proton nuclear magnetic resonance spectroscopy) and gut bacterial (16S ribosomal RNA gene amplicon sequencing) profiling approach was used to determine maternal longitudinal phenotypes associated with malabsorptive/mixed (n=25) or restrictive (n=16) procedures, compared with women with similar early pregnancy body mass index but without bariatric surgery (n=70). Metabolic profiles of offspring at birth were also analysed. RESULTS: Previous malabsorptive, but not restrictive, procedures induced significant changes in maternal metabolic pathways involving branched-chain and aromatic amino acids with decreased circulation of leucine, isoleucine and isobutyrate, increased excretion of microbial-associated metabolites of protein putrefaction (phenylacetlyglutamine, p-cresol sulfate, indoxyl sulfate and p-hydroxyphenylacetate), and a shift in the gut microbiota. The urinary concentration of phenylacetylglutamine was significantly elevated in malabsorptive patients relative to controls (p=0.001) and was also elevated in urine of neonates born from these mothers (p=0.021). Furthermore, the maternal metabolic changes induced by malabsorptive surgery were associated with reduced maternal insulin resistance and fetal/birth weight. CONCLUSION: Metabolism is altered in pregnant women with a previous malabsorptive bariatric surgery. These alterations may be beneficial for maternal outcomes, but the effect of elevated levels of phenolic and indolic compounds on fetal and infant health should be investigated further.

Keto acid profiling analysis as ethoxime/tert-butyldimethylsilyl derivatives by gas chromatography-mass spectrometry.

Organic acids, including keto acids, are key intermediates of central pathways in cellular metabolism. In this study, a comprehensive and reliable method was developed and optimized for the simultaneous measurement of 17 keto acids in various biological samples. The keto acids were converted to solvent extractable forms by ethoximation followed by tert-butyldimethylsilylation for direct analysis by gas chromatography-mass spectrometry in selected ion monitoring mode. The proposed method was precise (0.05-8.3, % RSD) and accurate (-10.5 to 5.3, % RE) with low limit of detection (0.01-0.5ng/mL) and good linearity (r>0.995) in the range of 0.01-5.0µg/mL. This was suitable for profiling analysis of targeted keto acids in human plasma, urine and rat brain tissue.

Enfermedad de orina en jarabe de arce: mejoría clínica asociada a detección precoz y manejo oportuno. Reporte de caso y revisión de literature / Doença de urina em xarope de arce: melhoria clínica relacionada á detecção precoce e manejo oportuno. Reporte de caso e revisão de literatura / Maple syrup urinary disease: clinical improvement associated with early detection and management. Case report and literature review

La enfermedad de orina en jarabe de arce es un error innato del metabolismo de los cetoácidos de cadena ramificada, cuya acumulación produce una encefalopatía neonatal grave y que de no ser diagnosticada y tratada de forma precoz y oportuna, lleva invariablemente a la aparición de secuelas neurológicas permanentes y a un posterior desenlace letal. El presente artículo busca, mediante la descripción de un caso clínico sucedido en el Hospital Militar Central de Bogotá, hacer una revisión de la literatura acerca de la enfermedad, resaltando los mecanismos fisiopatológicos, la detección por diferentes pruebas de laboratorio, así como las estrategias de manejo, demostrando que gracias a los progresos realizados en su comprensión y enfoque, actualmente se puede hablar de evitar la mortalidad, alcanzando en muchos casos, una sobrevida a largo plazo sin mayores secuelas neurológicas, todo ello con un manejo interdisciplinario que logre un control metabólico adecuado...

Maple syrup urine disease is an inborn error of the metabolism of branched chain keto-acids whose accumulation produces a serious neonatal encephalopathy, which if not diagnosed and treated in a precocious and opportune way, will invariably lead to the appearance of permanent neurological impairments and an ulterior lethal outcome. The present article intends, by means of the description of a clinical case which occurred at the Hospital Militar Central, to perform a review of the existent literature on this disease, to revise its fisiopathological mechanisms as well as its detection using different laboratory tests and the different care strategies, to demonstrate that, thanks to the progress achieved in its understanding and focus, at the present moment we can speak of avoiding mortality, accomplishing in many cases long term survival without important neurological consequences, all by means of an interdisciplinary approach that achieves an appropriate metabolic control...

A doença de urina em xarope de arce é um erro inato do metabolismo dos cetoácidos de corrente ramificada, cuja acumulação produz uma encefalopatia neonatal grave e que de não ser diagnosticada e tratada de forma precoce e oportuna, leva invariavelmente à aparição de seqüelas neurológicas permanentes e a um posterior desenlace letal. O presente artigo procura, mediante a descrição de um caso clínico sucedido no Hospital Militar Central de Bogotá, fazer uma revisão da literatura a respeito da doença, ressaltando os mecanismos fisiopatológicos, a detecção por diferentes provas de laboratório, bem como as estratégias de tratamento, demonstrando que graças aos progressos realizados em seu entendimento e enfoque, atualmente se pode falar de evitar a mortalidade, atingindo em muitos casos, uma sobrevida em longo prazo sem maiores seqüelas neurológicas, tudo isso com um manejo interdisciplinares que consiga um controle metabólico adequado...

Metabolism of myosmine in Wistar rats.

The alkaloid myosmine is present not only in tobacco products but also in various foods. Myosmine is easily nitrosated, yielding 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) and the esophageal tobacco carcinogen N'-nitrosonornicotine. Due to its widespread occurrence, investigations on the metabolism and activation of myosmine are needed for risk assessment. Therefore, the metabolism of myosmine has been studied in Wistar rats treated with single oral doses of [pyridine-5-3H]myosmine at 0.001, 0.005, 0.5, and 50 micromol/kg body weight. Oral administration was achieved by feeding a labeled apple bite. Radioactivity was completely recovered in urine and feces within 48 h. At the two lower doses, 0.001 and 0.005 micromol/kg, a higher percentage of the radioactivity was excreted in urine (86.2 +/- 4.9% and 88.9 +/- 1.7%) as compared with the higher doses, 0.5 and 50 micromol/kg, where only 77.8 +/- 7.3% and 75.4 +/- 6.6% of the dose was found in urine. Within 24 h, urinary excretion of radioactivity was nearly complete with less than 4% of the total urinary output appearing between 24 and 48 h. The two major metabolites accounting for >70% of total radioactivity in urine were identified as 3-pyridylacetic acid (20-26%) and 4-oxo-4-(3-pyridyl)butyric acid (keto acid, 50-63%) using UV-diode array detection and gas chromatography-mass spectrometry measurements. 3-Pyridylmethanol (3-5%), 3'-hydroxymyosmine (2%) and HPB (1-3%) were detected as minor metabolites. 3'-Hydroxymyosmine is exclusively formed from myosmine and therefore might be used as a urinary biomarker for myosmine exposure in the future.

A GC/MS/MS screening method for multiple organic acidemias from urine specimens.

A gas chromatography tandem mass spectrometry method using an ion trap GC/MS system was developed to quickly screen urine samples for 14 organic acids associated with multiple organic acidemias. The following organic acids are used as diagnostic markers: methylmalonic acid, glutaric acid, 2-ketoisocaproic acid, succinylacetone, 3-methylcrotonylglycine, tiglylglycine, isovalerylglycine, fumaric acid, butyrylglycine, propionylglycine, hexanoylglycine, adipic acid, suberic acid, and sebacic acid. 2-ketocaproic acid is used as an internal standard. The samples are prepared using a solid-phase extraction and converted to trimethylsilyl derivatives. The extraction efficiency for the 14 compounds is between 57 and 106%. A derivatized standard mixture of the 14 markers is run prior to the patient samples to determine the accurate absolute and relative retention times. The samples are then injected and the product ion spectra monitored. For data analysis, one characteristic product ion plot is extracted for each of the 14 marker compounds, and the presence of a peak with the expected retention time is determined. The areas of the product ion peaks are compared with the reference range determined from 30 normal controls. Ten samples of patients with known organic acidemias were measured. For all patients, diagnostic peaks at the expected retention times of at least five times the upper limit of the reference range were detected. The method, with its relatively fast sample preparation, short 10.0 min run time and simple data analysis, is suitable for use as a quick metabolic screen of very sick patients in whom there is concern regarding the possibility of a treatable inborn error.

Quantitation of 4-oxo-4-(3-pyridyl)butanoic acid and enantiomers of 4-hydroxy-4-(3-pyridyl)butanoic acid in human urine: A substantial pathway of nicotine metabolism.

A liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC-APCI-MS/MS) method was developed to analyze human urine for 4-oxo-4-(3-pyridyl)butanoic acid (keto acid) and the enantiomers of 4-hydroxy-4-(3-pyridyl)butanoic acid (hydroxy acid) to test our hypothesis that (S)-hydroxy acid could be a biomarker of metabolic activation of the tobacco-specific carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) while (R)-hydroxy acid would be formed predominantly from nicotine, as indicated by studies with rats. Urine was collected from smokers, and from the same individuals after they had stopped smoking and used a nicotine transdermal system (nicotine patch) for 3 weeks. If (S)-hydroxy acid were a biomarker of NNK and NNN metabolic activation, its levels should be higher in the urine of smokers than in nicotine patch users because tobacco smoke, but not the nicotine patch, contains NNK and NNN. Internal standard, [2,2,3,3,4-D5]hydroxy acid, was added to an aliquot of urine, which was then subjected to solid phase extraction. The eluant containing hydroxy acid was esterified with acidic methanol, followed by treatment with (S)-(-)-alpha-methylbenzyl isocyanate, producing methyl-4(S)- or methyl-4(R)-[(S)-alpha-methylbenzylcarbamoyl]-4-(3-pyridyl)buta noate [(S,S)- or (R,S)-MMPB, respectively]. After HPLC purification, the MMPB diastereomers were separated and quantified by LC-APCI-MS/MS. Mean levels of (S)- and (R)-hydroxy acid were 14.1 +/- 8.0 and 1120 +/- 600 ng/mL, respectively, in smokers during ad lib smoking (n = 18), while the corresponding levels during nicotine patch use (n = 18) were 4.1 +/- 3.3 and 363 +/- 228 ng/mL. The amounts of (S)-hydroxy acid were far higher than could be formed from NNK and NNN, and the total amount of hydroxy acid indicated that it was a substantial urinary metabolite of nicotine, in contrast to results with rats. Therefore, the study was extended to quantify keto acid. This was accomplished by NaBH4 treatment of urine, which converted keto acid to hydroxy acid quantitatively, which was in turn analyzed as described above. Levels of keto acid while subjects were smoking and using the nicotine patch were 228 +/- 129 (n = 8) and 97.5 +/- 80.6 ng/mL (n = 8), respectively. These results indicate that conversion of nicotine to keto acid and hydroxy acid is a substantial metabolic pathway in humans, accounting for an estimated 14% of the nicotine dose. Apparently, keto acid is extensively converted to hydroxy acid in humans, in contrast to the results with rats. (S)-Hydroxy acid in human urine cannot be used as a biomarker of NNK and NNN metabolic activation because it is overwhelmed by the (S)-hydroxy acid formed from nicotine, despite the fact that >98% of the urinary hydroxy acid has the (R)-configuration. These results provide new insights about nicotine metabolism in humans.

Identification of new cystathionine mono-oxo acids, S-(3-oxo-3-carboxy-n-propyl) cysteine and S-(2-oxo-2-carboxyethyl) homocysteine, in the urine of a patient with cystathioninuria.

Novel cystathionine mono-oxo acids, S-(3-oxo-3-carboxy-n-propyl) cysteine and S-(2-oxo-2-carboxyethyl) homocysteine, and cyclic amino acid, cystathionine ketimine, have been detected in the urine of a patient with cystathioninuria using liquid chromatography-mass spectrometry with an atmospheric pressure ionization interface system and an amino acid analyzer. To determine these cystathionine mono-oxo acids and cystathionine ketimine we took advantage of the selective absorbance at 380 nm of the phenylisothiocyanate-ketimine interaction product. The total concentrations of these compounds found in the urine samples of a cystathioninuric patient and six healthy subjects were respectively 3611.3 and 148.4 micrograms +/- 35.9/g of creatinine. The cystathioninuric patient excreted 20 times more cystathionine mono-oxo acids in the urine than healthy subjects.

Nutrition support of inborn errors of amino acid metabolism.

Programs for nutrition support of patients with phenylketonuria, maternal phenylketonuria, branched chain ketoaciduria and vitamin B-6 non-responsive homocystinuria were written in BASIC. These programs plan diets to fill diet prescriptions using natural foods, available amino acid-free or restricted elemental products, milk or infant proprietary formulae and protein-free fat and carbohydrate sources. Emphasis is placed on satisfying the amino acid and protein prescriptions simultaneously. The final semisynthetic formula is evaluated for vitamins, minerals, renal solute load and renal net acid excretion. Fluid requirement is estimated. The paper describes how the conventional protocols are enhanced by computerization and details the requisite calculations.

Deficiency of fumarylacetoacetase in a patient with hereditary tyrosinemia.

A patient is described with type I tyrosinemia characterized by urinary excretion of succinylacetone together with increased excretion of tyrosine, p-hydroxyphenyllactic, p-hydroxyphenylpyruvic and p-hydroxyphenylacetic acids. Fumarylacetoacetase was measured in a liver biopsy and found to be very low compared to control liver. Furthermore the mass spectra of succinylacetone and fumarylacetoacetate (methoxime-TMS derivatives) are reported. Control jejunal mucosa, leucocytes and fibroblasts showed no enzyme activity; hence the prenatal diagnosis of this disease by measuring the fumarylacetoacetase activity in cultured amniotic fluid cells is not possible at present.

Isolation and identification of 2-oxo-5-guanidinovaleric acid in urine of patients with hyperargininaemia by chromatography and gas chromatography/mass spectrometry.

An unknown guanidino-positive peak has been identified in urines of three sisters affected with hyperargininaemia. Identification was made on the basis of its similarity with the liquid and thin-layer chromatographic characteristics of enzymatically synthesized 2-oxo-5-guanidinovaleric acid. Identification was also made by combined gas chromatography-mass spectrometry of the unknown compound peak. The synthesis of enzymatically formed 2-oxo-5-guanidinovaleric acid was controlled by nuclear magnetic resonance and combined gas chromatography-mass spectrometry.

O-trimethylsilylquinoxalinol derivatives of aromatic alpha-keto acids. Mass spectra and quantitative gas chromatography.

As an extension of earlier work on aliphatic alpha-keto acids, a method is described for the quantitative gas chromatographic determination of urinary aromatic alpha-keto acids. The keto acids are derivatized with o-phenylenediamine to yield the quinoxalinols. These compounds are chromatographed after trimethylsilylation. The aromatic keto acids are stabilized by sodium dithionite (4 mg/ml urine) and storage below 0 degrees. The final derivatives are stable for weeks at room temperature. Low resolution mass spectra are reported. The fragmentation mechanisms are elucidated by analysis of O-trimethylsilyl-(TMS)-quinoxalinois, O-(TMS-d9)-quinoxalinois and O-TMS-6(7)-chloroquinoxalinois.

Application of glass capillary-column gas chromatography-mass spectrometry to the studies of human diseases.

Open-tubular glass capillary columns have been used in gas chromatography in combination with mass spectrometry (GC-MS) and computer methods to study human diseases. Patients with maple syrup urine disease excrete not only alpha-keto and alpha-hydroxy acids but also six other metabolites which hitherto have been overlooked. The GC-MS methods demonstrated that a group of patients suffering from hereditary progressive loss of hearing have an impaired metabolism of leucine, leading to the accumulation of 3-hydroxyisovaleric acid and 3-methylcrotonylglycine. GC using the capillary columns proved suitable for mapping of the carbohydrate profile of human seminal fluid and for the analyses of organic compounds accumulating in human adipose tissue. The high resolving power and long life of the glass capillary columns suggest that they will be valuable in the diagnosis and study of human disorders.