Acylcarnitine Profiles Research Articles

Insulin Receptor Autoantibody–mediated Hypoglycemia in a Woman With Mixed Connective Tissue Disease

Autoantibodies to the insulin receptor are rare and typically cause severe insulin resistance and hyperglycemia, a condition termed type B insulin resistance. Uncommonly, antibodies to the insulin receptor can cause hypoglycemia. We present the case of a woman who developed recurrent severe hypoglycemia and myopathy, was found to have insulin receptor autoantibodies and mixed connective tissue disease, and had resolution of hypoglycemia with immunosuppression. A 55-year-old woman with a history of obesity, hypertension, and prior hemorrhagic stroke presented with recurrent severe hypoglycemia. A diagnostic fast resulted in hypoinsulinemic hypoketotic hypoglycemia. Adrenal function was intact. Progressive myopathy had developed simultaneously with her hypoglycemia, and rheumatologic evaluation revealed mixed connective tissue disease. The plasma acylcarnitine profile was normal, extensive oncologic evaluation including insulin-like growth factor 2 measurement was unrevealing, and anti-insulin antibody testing was negative. Ultimately, anti-insulin receptor antibodies were found to be present. The patient was treated with glucocorticoids and rituximab. Eight weeks after initiation of immunosuppression, the insulin receptor antibody titer had decreased and hypoglycemia had resolved. Eight months after diagnosis, the patient remained free of severe hypoglycemia despite tapering of glucocorticoids to a near-physiologic dose. Though antibodies to the insulin receptor typically cause severe insulin resistance, this patient had no evidence of insulin resistance and instead presented with recurrent severe hypoglycemia, which responded to glucocorticoids and rituximab. The diagnosis of insulin receptor antibody–mediated hypoglycemia is rare but should be considered in patients with systemic autoimmune disease, including mixed connective tissue disease, in the appropriate clinical context.

Diagnosis of atypical myopathy based on organic acid and acylcarnitine profiles and evolution of biomarkers in surviving horses

BackgroundAtypical myopathy (AM), an acquired multiple acyl-CoA dehydrogenase deficiency (MADD) in horses, induce changes in mitochondrial metabolism. Only few veterinary laboratories offer diagnostic testing for this disease. Inborn and acquired MADD exist in humans, therefore determination of organic acids (OA) in urine and acylcarnitines (AC) in blood by assays available in medical laboratories can serve as AM diagnostics. The evolution of OA and AC profiles in surviving horses is unreported. MethodsAC profiles using electrospray ionization tandem mass spectrometry (ESI-MS/MS) and OA in urine using gas chromatography mass spectrometry (GC–MS) were determined in dried blot spots (DBS, n = 7) and urine samples (n = 5) of horses with AM (n = 7) at disease presentation and in longitudinal samples from 3/4 survivors and compared to DBS (n = 16) and urine samples (n = 7) from control horses using the Wilcoxon test. ResultsAll short- (C2-C5) and medium-chain (C6-C12) AC in blood differed significantly (p < 0.008) between horses with AM and controls, except for C5:1 (p = 0.45) and C5OH + C4DC (p = 0.06). In AM survivors the AC concentrations decreased over time but were still partially elevated after 7 days. 14/62 (23%) of OA differed significantly between horses with AM and control horses. Concentrations of ethylmalonic acid, 2-hydroxyglutaric acid and the acylglycines (butyryl-, valeryl-, and hexanoylglycine) were highly elevated in the urine of all horses with AM at the day of disease presentation. In AM survivors, concentrations of those metabolites were initially lower and decreased during remission to approach normalization after 7 days. ConclusionOA and AC profiling by specialized human medical laboratories was used to diagnose AM in horses. Elevation of specific metabolites were still evident several days after disease presentation, allowing diagnosis via analysis of samples from convalescent animals.

Clinical and Genetic Spectrum of 50 Children with Inborn Errors of Metabolism from Central India.

This is a single-center, retrospective analysis of children confirmed to have an inborn error of metabolism in the pediatric department of a teaching hospital in central India. Patients were categorized as acute encephalopathy, developmental delay/seizures, and neuroregression or organomegaly depending on their predominant phenotype. Of the 50 patients analyzed, the commonest group was lysosomal storage disorders in 13 (26%), followed by organic acidurias - 8 (16%), mitochondrial disorders - 5 (10%), urea cycle disorders, carbohydrate metabolism disorders, and amino acidopathies - 4 (8%) each, fatty acid oxidation defects and neurotransmitter deficiency disorders - 3 (6%) each, and miscellaneous (8%). Genetic variations were identified in 25 (50%). Acylcarnitine profiles and urine organic acids were diagnostic in 62.5% of children presenting as acute encephalopathy, exome sequencing in 55.5% of children with neuroregression, and specific enzyme assay in 83.3% of children with predominant organomegaly (83.3%). Children with developmental delay/seizures needed a wider range of tests.

Profiling of Carnitine Shuttle System Intermediates in Gliomas Using Solid-Phase Microextraction (SPME).

Alterations in the carnitine shuttle system may be an indication of the presence of cancer. As such, in-depth analyses of this pathway in different malignant tumors could be important for the detection and treatment of this disease. The current study aims to assess the profiles of carnitine and acylcarnitines in gliomas with respect to their grade, the presence of isocitrate dehydrogenase (IDH) mutations, and 1p/19q co-deletion. Brain tumors obtained from 19 patients were sampled on-site using solid-phase microextraction (SPME) immediately following excision. Analytes were desorbed and then analyzed via liquid chromatography–high-resolution mass spectrometry. The results showed that SPME enabled the extraction of carnitine and 22 acylcarnitines. An analysis of the correlation factor revealed the presence of two separate clusters: short-chain and long-chain carnitine esters. Slightly higher carnitine and acylcarnitine concentrations were observed in the higher-malignancy tumor samples (high vs. low grade) and in those samples with worse projected clinical outcomes (without vs. with IDH mutation; without vs. with 1p/19q co-deletion). Thus, the proposed chemical biopsy approach offers a simple solution for on-site sampling that enables sample preservation, thus supporting comprehensive multi-method analyses.

Effects of gut microbiota and fatty acid metabolism on dyslipidemia following weight-loss diets in women: Results from a randomized controlled trial

In our early feeding trial among overweight and obese Chinese women, both low-carbohydrate (LC) and calorie-restricted (CR) diets reduced weight and fat mass, but only the LC diet significantly improved dyslipidemia. We aimed to investigate the impacts of altered gut microbiota, fatty acid (FAs), and acylcarnitines, markers of mitochondrial function on blood lipids. Fecal and blood samples from 48 participants at baseline and the end of a 12-week trial were used to perform metagenomics and targeted-metabolomics including erythrocyte FAs and plasma acylcarnitines, respectively. The two diets altered microbial structure and co-abundance gene clusters (CAGs) at different magnitudes. After a 12-week intervention, the Bacteroidetes/Firmicutes ratio increased significantly in the LC diet (P=0.015) but not in the CR diet, which only showed an increased trend (P=0.28). At the microbial function level, the LC group showed lower branched-chain amino acid biosynthesis and higher serine biosynthesis than the CR group. Moreover, the LC diet reduced levels of 14:0 and 16:1n-7 FAs in the de novo lipogenesis pathway, but increased 20:5n-3 compared with the CR diet. Both groups had increased plasma acylcarnitines except that the LC group had larger elevated short-chain acylcarnitines. After backward stepwise selection, a cluster of changed CAGs, FAs and acylcarnitines were found to be associated with improved lipid profile. However, changed CAGs showed higher contribution rates in elevating HDL-cholesterol (81.6%) and reducing triglycerides (89.3%) than changed FAs and acylcarnitines. The two weight-loss diets induced different changes of gut microbiota, plasma acylcarnitines, and erythrocyte FAs. Changes in gut microbiota rather than FA or acylcarnitine profiles showed greater contribution to improved lipid profile in these overweight and obese Chinese women. The trial was registered at http://clinicaltrials.gov/show/NCT01358890.

A single bout of cycling exercise induces nucleosome repositioning in the skeletal muscle of lean and overweight/obese individuals.

To compare the molecular and metabolic effects of a single exercise bout in the skeletal muscle between lean and overweight/obese (Ov/Ob) individuals. Participants recruited were men, aged 19-30 years, who were either lean (body mass index [BMI] < 25, 18.5-24.1 kg/m2 ; n = 15) or Ov/Ob (BMI ≥ 25, 25.5-36.9 kg/m2 ; n = 15). Four hours after a high-carbohydrate breakfast (7kcal/kg; 60% carbohydrate, 25% fat, 15% protein), participants performed a cycling exercise (50% VO2 max, expending ~650 kcal). Muscle biopsies and peripheral blood samples were collected 30 minutes before the meal and immediately after exercise. Blood analysis, and muscle acylcarnitine profiles, transcriptomics, and nucleosome mapping by micrococcal nuclease digestion with deep sequencing were performed. A single exercise bout improved blood metabolite profiles in both lean and Ov/Ob individuals. Muscle long-chain acylcarnitines were increased in Ov/Ob compared with lean participants, but were not altered by exercise. A single exercise bout increased the mRNA abundance of genes related to mitochondria and insulin signalling in both lean and Ov/Ob participants. Nucleosome mapping by micrococcal nuclease digestion with deep sequencing revealed that exercise repositioned the -1 nucleosome away from the transcription start site of the PGC1a promoter and of other mitochondrial genes, but did not affect genes related to insulin signalling, in both lean and Ov/Ob participants. These data suggest that a single exercise bout induced epigenetic alterations in skeletal muscle in a BMI-independent manner.

Abstract MP237: Multi-omics Profiling Reveals Stearoylcarnitine As A Novel Biomarker Of Cardiometabolic Disease Development In Rat Offspring Exposed To Gestational Diabetes

Through unknown mechanisms, fetal exposure to gestational diabetes mellitus (GDM) increases the risk for cardiovascular disease development later in life. We hypothesize that fetal exposure to GDM alters offspring cardiomyocyte metabolism and left ventricular (LV) function with age. To induce GDM, female rats were fed a high fat (45% kcal) and sucrose diet prior to mating, throughout pregnancy and lactation. Lean controls received a low fat (10% kcal) diet. Fetal rat ventricular cardiomyocytes (FRVC) were isolated from e20 offspring for U-13C glucose metabolic flux analysis, mitochondrial respiration and calcium handling. The cardiac transcriptome and metabolome were measured in 3-month old offspring. LV morphology and function was assessed in the offspring from e18 to 12-months of age by transthoracic ultrasound. Offspring exposed to GDM exhibited increased LV posterior wall thickness and impaired LV filling across their life course (fetal to 12-months of age; p&lt;0.05). Consistent with the development of diastolic dysfunction in vivo, alterations in calcium flux and sarcoplasmic reticulum-dependent calcium re-uptake (1.5 and 1.6-fold greater, respectively) were observed in FRVC isolated from GDM offspring (p&lt;0.05). When FRVC were treated with isoproterenol, U-13C glucose metabolic flux through glycolysis and the citric acid cycle was reduced in GDM offspring, compared to Lean controls. In 3-month old GDM offspring serum and cardiac metabolomics revealed an altered acylcarnitine profile, with specific elevation in long chain acylcarnitine species including stearoylcarnitine. Alterations in the metabolome corresponded to changes in gene expression patterns identified by RNA-Seq associated with glucose metabolism and fatty acid transport pathways (e.g. Irs2, Slc2a4, Pfkfb2, Pdk4 and Cpt1a). These alterations corresponded with mitochondrial dysfunction, impaired cardiomyocyte metabolic flux and contractility, in concert with LV hypertrophy and diastolic dysfunction in the rat offspring. Multi-omics profiling reveals stearoylcarnitine as a novel biomarker and implicates mitochondrial oxidative metabolism as a mechanism that links early-life GDM exposure to the development of cardiovascular disease later in life.

Heart failure is associated with accumulation of long chain acylcarnitines in children suffering from cardiomyopathy

Cardiac failure in adults is associated with down regulation of fatty acid beta oxidation and accumulation of long chain (LC) fatty acid derivatives such as LC acylcarnitines [1] , [2] . These lipidomic disturbances have been shown to impair cardiac function [3] . No data are available concerning metabolic modification in heart failure in children. We retrospectively collected acylcarnitines profiles, NT pro BNP, clinical and echographical data and MRI performed in children explored for a non-metabolic cardiomyopathy in our centre from 2015 to 2021. Eighteen children aged from 1 month to 16 years old (median 2.7 years old) met the inclusion criteria. Thirteen were diagnosed for a dilated cardiomyopathy (DCM) [with normal left ventricular ejection fraction (LVEF) for 5 of them], 4 had a hypertrophic cardiomyopathy and 1 suffered from a restrictive cardiomyopathy. Seven children had clinical symptoms of cardiac insufficiency, and nine showed elevation of NT pro BNP. Considering first only children with DCM, sum of total acylcarnitines and sum of LC acylcarnitines were significantly enhanced in patients with impaired LVEF compared to those with normal LVEF (40.0 ± 16.8 vs. 16.2 ± 5.7 μM, P < 0.01, and 4.8 ± 1.6 vs. 3.1 ± 0.7 μM, P < 0.05, respectively). Similarly, considering the whole patients with cardiomyopathy, children with an elevation of NT pro BNP level displayed accumulation of total acylcarnitines and LC acylcarnitines compared to those with a normal NT pro BNP level (38.9 ± 16.9 vs. 15.5 ± 8.2 μM, P < 0.01, and 5.2 ± 2.4 vs. 2.8 ± 1.1 μM, P < 0.01, respectively). Our results suggest alteration of fatty acid oxidation in children with cardiomyopathy and impaired LVEF or elevated NT pro BNP. This metabolic modification needs to be confirmed with a larger scale study. Such lipidomic alteration could worsen heart function, and may suggest considering a metabolic treatment of heart failure in children.

A novel mutation in ACADVL causing very long-chain acyl-coenzyme-A dehydrogenase deficiency in a South Asian pediatric patient: a case report and review of the literature

BackgroundVery long-chain acyl-coenzyme-A dehydrogenase deficiency is a rare, severe life-threatening metabolic disorder of mitochondrial fatty acid oxidation, caused by mutations in ACADVL gene. Here we present a genetically confirmed case of a South Asian baby girl with severe, early-onset form of very long-chain acyl-coenzyme-A dehydrogenase deficiency due to a novel mutation in ACADVL gene.Case presentationIndex case was the second baby girl of second-degree consanguineous South Asian parents. She had an uncomplicated antenatal period and was born by spontaneous vaginal delivery at term with a birth weight of 2910 g. She had been noted to have fair skin complexion, hypotonia, and 3 cm firm hepatomegaly. Since birth, the baby developed grunting, poor feeding, and recurrent episodes of symptomatic hypoglycemia and convulsions with multiple semiology. Her septic screening and urine ketone bodies were negative. The baby had high anion gap metabolic acidosis and elevated transaminases and serum creatine phosphokinase levels. Echocardiogram at 4 months revealed bilateral ventricular hypertrophy. Acylcarnitine profile revealed elevated concentrations of tetradecanoylcarnitine (C14), tetradecanoylcarnitine C14:1, and C14:1/C16. Unfortunately, the baby died due to intercurrent respiratory illness at 4 months of age. Sequence analysis of ACADVL gene in perimortem blood sample revealed homozygous frame shift novel variant NM_001270447.1, c.711_712del p.(Phe237Leufs*38), which confirmed the diagnosis of very long-chain acyl-coenzyme-A dehydrogenase deficiency.ConclusionsThis case demonstrates the importance of early diagnosis and management of very long-chain acyl-coenzyme-A dehydrogenase deficiency in improving the outcome of the patients. Implementation of newborn screening using tandem mass spectrometry in Sri Lanka will be beneficial to reduce the morbidity and mortality of treatable disorders of inborn errors.

Nutrient-related metabolite profiles explain differences in body composition and size in Nile tilapia (Oreochromis niloticus) from different lakes

This study investigated how metabolite analysis can explain differences in tissue composition and size in fish from different habitats. We, therefore, studied Nile tilapia (Oreochromis niloticus) from three Ethiopian lakes (Gilgel Gibe, Ziway, and Langano) using dried bloodspot (DBS) analysis of carnitine esters and free amino acids. A total of sixty (N = 60) Nile tilapia samples were collected comprising twenty (n = 20) fish from each lake. The proximate composition of the targeted tissues (muscle, skin, gill, gut, and liver) were analyzed. The DBS samples were analyzed for acylcarnitine and free amino acid profiles using quantitative electrospray tandem mass spectrometry. Metabolite ratios were calculated from relevant biochemical pathways that could identify relative changes in nutrient metabolism. The mean weight of Nile tilapia sampled from each lake showed weight variation among the lakes, fish from Lake Ziway were largest (178 g), followed by Gilgel Gibe reservoir (134 g) and Lake Langano (118 g). Fish from Gilgel Gibe showed significantly higher fat composition in all tissues (P < 0.05) except the liver in which no significant variation was observed. The source of fish affected the tissue fat composition. Marked differences were observed in Nile tilapia metabolic activity between the lakes. For instance, the lower body weight and condition of the fish in Lake Langano coincided with several metabolite ratios pointing to a low flow of glucogenic substrate to the citric acid cycle. The low propionyl to acetylcarnitine ratio (C3:C2) in Gilgel Gibe fish is indicating that more of the available acetyl CoA is not led into the citric acid cycle, but instead will be used for fat synthesis. The metabolic markers for lipogenesis and metabolic rate could explain the high-fat concentration in several parts of the body composition of fish from Gilgel Gibe. Our results show that nutrition-related blood metabolite ratios are useful to understand the underlying metabolic events leading to the habitat-dependent differences in the growth of Nile tilapia, and by extension, other species.

The effect of combined oral contraceptives containing drospirenone and ethinylestradiol on serum levels of amino acids and acylcarnitines.

Metabolome variations have long been associated with normal hormonal fluctuations, and similar effects, related to the use of early generation synthetic hormones as a means of contraception, have also been identified. We investigated the serum amino acid and acylcarnitine profiles induced by the use of combined oral contraceptives (COCs) consisting of Ethinylestradiol (EE) and a 4th generation progestin, Drospirenone (DRSP). Gas chromatography mass spectrometry and liquid chromatography with tandem mass spectrometry was used to identify and quantify the serum amino acids and acyl carnitine levels in 24 controls, 25 DRSP/20EE users and 26 DRSP/30EE users. Of the 26 amino acid compounds measured, 13 showed significant variations in abundance between the control and COC user groups. Although none of the 21 acylcarnitine compounds detected were statistically significant with regards to group variations, a trend, related the EE concentration, was observed. The detected metabolome disparities corresponded to that identified for earlier generation COCs, all pointing toward increased oxidative stress levels in the user groups. These findings suggest that the clinical complications associated with these COCs could, to some extent, be alleviated by the simultaneous use of antioxidants. The study also highlights the role that targeted metabolomics could play in the elucidation of the underlying mechanisms of drug-induced severe effects.

Metabolic Outcomes of Anaplerotic Dodecanedioic Acid Supplementation in Very Long Chain Acyl-CoA Dehydrogenase (VLCAD) Deficient Fibroblasts.

Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD, OMIM 609575) is associated with energy deficiency and mitochondrial dysfunction and may lead to rhabdomyolysis and cardiomyopathy. Under physiological conditions, there is a fine balance between the utilization of different carbon nutrients to maintain the Krebs cycle. The maintenance of steady pools of Krebs cycle intermediates is critical formitochondrial energy homeostasis especially in high-energy demanding organs such as muscle and heart. Even-chain dicarboxylic acids are established as alternative energy carbon sources that replenish the Krebs cycle by bypassing a defective β-oxidation pathway. Despite this, even-chain dicarboxylic acids are eliminated in the urine of VLCAD-affected individuals. In this study, we explore dodecanedioic acid (C12; DODA) supplementation and investigate its metabolic effect on Krebs cycle intermediates, glucose uptake, and acylcarnitine profiles in VLCAD-deficient fibroblasts. Our findings indicate that DODA supplementation replenishes the Krebs cycle by increasing the succinate pool, attenuates glycolytic flux, and reduces levels of toxic very long-chain acylcarnitines.

Acylcarnitine profile in Alaskan sled dogs during submaximal multiday exercise points out metabolic flexibility and liver role in energy metabolism.

Alaskan sled dogs develop a particular metabolic strategy during multiday submaximal exercise, allowing them to switch from intra-muscular to extra-muscular energy substrates thus postponing fatigue. Specifically, a progressively increasing stimulus for hepatic glycogenolysis and gluconeogenesis provides glucose for both fueling exercise and replenishing the depleted muscle glycogen. Moreover, recent studies have shown that with continuation of exercise sled dogs increase their insulin-sensitivity and their capacity to transport and oxidize glucose and carbohydrates rather than oxidizing fatty acids. Carnitine and acylcarnitines (AC) play an essential role as metabolic regulators in both fat and glucose metabolism; they serve as biomarkers in different species in both physiologic and pathologic conditions. We assessed the effect of multiday exercise in conditioned sled dogs on plasma short (SC), medium (MC) and long (LC) chain AC by tandem mass spectrometry (MS/MS). Our results show chain-specific modification of AC profiles during the exercise challenge: LCACs maintained a steady increase throughout exercise, some SCACs increased during the last phase of exercise and acetylcarnitine (C2) initially increased before decreasing during the later phase of exercise. We speculated that SCACs kinetics could reflect an increased protein catabolism and C2 pattern could reflect its hepatic uptake for energy-generating purposes to sustain gluconeogenesis. LCACs may be exported by muscle to avoid their accumulation to preserve glucose oxidation and insulin-sensitivity or they could be distributed by liver as energy substrates. These findings, although representing a “snapshot” of blood as a crossing point between different organs, shed further light on sled dogs metabolism that is liver-centric and more carbohydrate-dependent than fat-dependent and during prolonged submaximal exercise.

Biochemical and molecular features of Chinese patients with glutaric acidemia type 1 detected through newborn screening

BackgroundGlutaric acidemia type 1 (GA1) is a treatable disorder affecting cerebral organic acid metabolism caused by a defective glutaryl-CoA dehydrogenase (GCDH) gene. GA1 diagnosis reports following newborn screening (NBS) are scarce in the Chinese population. This study aimed to assess the acylcarnitine profiles and genetic characteristics of patients with GA1 identified through NBS.Results From January 2014 to September 2020, 517,484 newborns were screened by tandem mass spectrometry, 102 newborns with elevated glutarylcarnitine (C5DC) levels were called back. Thirteen patients were diagnosed with GA1, including 11 neonatal GA1 and two maternal GA1 patients. The incidence of GA1 in the Quanzhou region was estimated at 1 in 47,044 newborns. The initial NBS results showed that all but one of the patients had moderate to markedly increased C5DC levels. Notably, one neonatal patient with low free carnitine (C0) level suggest primary carnitine deficiency (PCD) but was ultimately diagnosed as GA1. Nine neonatal GA1 patients underwent urinary organic acid analyses: eight had elevated GA and 3HGA levels, and one was reported to be within the normal range. Ten distinct GCDH variants were identified. Eight were previously reported, and two were newly identified. In silico prediction tools and protein modeling analyses suggested that the newly identified variants were potentially pathogenic. The most common variant was c.1244-2 A>C, which had an allelic frequency of 54.55% (12/22), followed by c.1261G>A (p.Ala421Thr) at 9.09% (2/22).ConclusionsNeonatal GA1 patients with increased C5DC levels can be identified through NBS. Maternal GA1 patients can also be detected using NBS due to the low C0 levels in their infants. Few neonatal GA1 patients may have atypical acylcarnitine profiles that are easy to miss during NBS; therefore, multigene panel testing should be performed in newborns with low C0 levels. This study indicates that the GCDH variant spectra were heterogeneous in this southern Chinese cohort.

Serum Lipid, Amino Acid and Acylcarnitine Profiles of Obese Cats Supplemented with Dietary Choline and Fed to Maintenance Energy Requirements.

Simple SummaryResearch has estimated that the majority of domestic cats are overweight or obese. Current weight-loss plans tend to have disappointing outcomes and are not without risk. During periods of severe energy restriction, obesity predisposes cats to developing fatty liver. Choline has been linked to fat metabolism in other animals but has not been studied in cats. Twelve obese cats were split into two groups and were fed a control diet (n = 6; 4587 mg choline/kg dry matter) or a high choline diet (n = 6; 18,957 mg choline/kg DM) for 5 weeks. Cats were fed to maintain body weight. Choline increased serum cholesterol, triacylglycerides, lipoproteins, and plasma methionine. It also decreased serum blood urea nitrogen and alkaline phosphatase as well as the ratio of plasma acylcarnitine to free carnitine. The results suggest that choline supplementation may increase fat transport out of the liver and help maintain liver health in obese cats. Choline supplementation may prove useful for safe weight loss in obese cats by minimizing the risks of fatty liver.Obesity is a health concern for domestic cats. Obesity and severe energy restriction predispose cats to feline hepatic lipidosis. As choline is linked to lipid metabolism, we hypothesized that dietary choline supplementation would assist in reducing hepatic fat through increased lipoprotein transport and fatty acid oxidation. Twelve obese cats (body condition score [BCS] ≥ 8/9) were split into two groups. Cats were fed a control (n = 6; 4587 mg choline/kg dry matter [DM]) or a high choline diet (n = 6; 18,957 mg choline/kg DM) for 5 weeks, for adult maintenance. On days 0 and 35, fasted blood was collected, and the body composition was assessed. Serum lipoprotein and biochemistry profiles, plasma amino acids and plasma acylcarnitines were analyzed. The body weight, BCS and body composition were unaffected (p > 0.05). Choline increased the serum cholesterol, triacylglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol and plasma methionine (p < 0.05) and decreased the serum blood urea nitrogen and alkaline phosphatase (p < 0.05). Choline also reduced the plasma acylcarnitine to free carnitine ratio (p = 0.006). Choline may assist in eliminating hepatic fat through increased fat mobilization and enhanced methionine recycling.

Prospective diagnosis of MT-ATP6-related mitochondrial disease by newborn screening

Elevated citrulline and C5-OH levels are reported as part of the newborn screening of core and secondary disorders on the Recommended Uniform Screening Panel (RUSP). Additionally, some state laboratory newborn screening programs report low citrulline levels, which may be observed in proximal urea cycle disorders. We report six patients who were found on newborn screening to have low citrulline and/or elevated C5-OH levels in whom confirmatory testing showed the combination of these two abnormal analytes. Mitochondrial sequencing revealed known pathogenic variants in MT-ATP6 at high heteroplasmy levels in all cases. MT-ATP6 at these heteroplasmy levels is associated with Leigh syndrome, a progressive neurodegenerative disease. Patients were treated with supplemental citrulline and, in some cases, mitochondrial cofactor therapy. These six patients have not experienced metabolic crises or developmental regression, and early diagnosis and management may help prevent the neurological sequelae of Leigh syndrome. The affected mothers and siblings are asymptomatic or paucisymptomatic (e.g. intellectual disability, depression, migraines, obsessive-compulsive disorder, and poor balance) despite high heteroplasmy or apparent homoplasmy of the familial variant, thus expanding the clinical spectrum seen in pathogenic variants of MT-ATP6. Confirmatory plasma amino acid analysis and acylcarnitine profiling should be ordered in a patient with either low citrulline and/or elevated C5-OH, as this combination appears specific for pathogenic variants in MT-ATP6.

Early-adolescent antibiotic exposure results in mitochondrial and behavioral deficits in adult male mice

Exposure to antibiotic treatment has been associated with increased vulnerability to various psychiatric disorders. However, a research gap exists in understanding how adolescent antibiotic therapy affects behavior and cognition. Many antibiotics that target bacterial translation may also affect mitochondrial translation resulting in impaired mitochondrial function. The brain is one of the most metabolically active organs, and hence is the most vulnerable to impaired mitochondrial function. We hypothesized that exposure to antibiotics during early adolescence would directly affect brain mitochondrial function, and result in altered behavior and cognition. We administered amoxicillin, chloramphenicol, or gentamicin in the drinking water to young adolescent male wild-type mice. Next, we assayed mitochondrial oxidative phosphorylation complex activities in the cerebral cortex, performed behavioral screening and targeted mass spectrometry-based acylcarnitine profiling in the cerebral cortex. We found that mice exposed to chloramphenicol showed increased repetitive and compulsive-like behavior in the marble burying test, an accurate and sensitive assay of anxiety, concomitant with decreased mitochondrial complex IV activity. Our results suggest that only adolescent chloramphenicol exposure leads to impaired brain mitochondrial complex IV function, and could therefore be a candidate driver event for increased anxiety-like and repetitive, compulsive-like behaviors.

Plasma Acylcarnitines During Pregnancy and Neonatal Anthropometry: A Longitudinal Study in a Multiracial Cohort

ObjectivesPlasma profile of acylcarnitines has been suggested to associate with adverse maternal outcomes such as gestational diabetes. However, data on their associations with neonatal outcomes are sparse. Therefore, this study aimed to examine the prospective profile of acylcarnitines across gestation and its association with neonatal anthropometry, including birthweight (BW), BW z-score, the sum of skinfolds (SSF), length, and circumferences. MethodsAmong 321 pregnant women from the NICHD Fetal Growth Studies-Singletons cohort, we quantified 28 acylcarnitines using electrospray ionization tandem mass spectrometry in the plasma at gestational weeks 10–14, 15–26, 23–31 and 33–39, accordingly. We firstly applied a latent-class trajectory approach to identify trajectories of acylcarnitines across gestation, and secondly examined associations of individual acylcarnitine and distinct trajectory groups with neonatal anthropometry using weighted linear models with robust standard errors, adjusting for maternal age, race/ethnicity, education, parity, gestational week of blood collection, and pre-pregnancy body mass index. ResultsWe identified three distinct trajectory groups of C2, C3 and C4, and two trajectory groups of C5, C10, C5-DC, C8:1, C10:1 and C12, respectively. Newborns of women with nonlinear decline of C12 levels across gestation (5.7%) had significantly smaller BW (–475 g; 95% CI: –942, –6.79 g), BW z-score (–0.39; –0.71, –0.06), and length (–1.38 cm; –2.49, –0.27 cm) than those with persistently stable C12 levels (94.3%). Newborns of women with consistently higher levels of C10 (6.1%) had greater sum of skinfolds (4.91 mm; 0.85, 8.98 mm) than those with lower levels (93.9%) across pregnancy, whereas newborns of women with declining C10:1 levels (12.6%) had larger sum of skinfolds (3.23 mm; 0.19, 6.27 mm) than those with abruptly increasing levels (87.4%). ConclusionsIn conclusion, gestational trajectories of C10, C10:1, and C12 acylcarnitine levels were significantly associated with neonatal anthropometry. Further studies are needed to verify and further explore the potential clinical utility of these findings. Funding SourcesEunice Kennedy Shriver National Institute of Child Health and Human Development intramural funding; American Recovery and Reinvestment Act funding.

Chronological Metabolic Response to Intensive Phase TB Therapy in Patients with Cured and Failed Treatment Outcomes.

Despite the arguable success of the standardized tuberculosis (TB) treatment regime, a significant number of patients still present with treatment failure. To improve on current TB treatment strategies, we sought to gain a better understanding of the hosts' response to TB therapy. A targeted metabolomics approach was used to compare the urinary acylcarnitine and amino acid profiles of eventually cured TB patients with those of patients presenting with a failed treatment outcome, comparing these patient groups at the time of diagnosis and at weeks 1, 2, and 4 of treatment. Among the significant metabolites identified were histidine, isoleucine, leucine, methionine, valine, proline, tyrosine, alanine, serine, and γ-aminobutyric acid. In general, metabolite fluctuations in time followed a similar pattern for both groups for most compounds but with a delayed onset or shift of the pattern in the successfully treated patient group. These time-trends detected in both groups could potentially be ascribed to a vitamin B6 deficiency and fluctuations in the oxidative stress levels and urea cycle intermediates, linked to the drug-induced inhibition and stimulation of various enzymes. The earlier onset of observed trends in the failed patients is proposed to relate to genotypic and phenotypic variations in drug metabolizing enzymes, subsequently leading to a poor treatment efficiency either due to the rise of adverse drug reactions or to insufficient concentrations of the active drug metabolites. This study emphasizes the need for a more personalized TB treatment approach, by including enzyme phenotyping and the monitoring of oxidative stress and vitamin B6 levels, for example.

Abstract P166: Plasma Acylcarnitines During Pregnancy And Neonatal Anthropometry: A Prospective And Longitudinal Study

As surrogate readouts reflecting tissue acyl-CoA pools, elevated levels of plasma acylcarnitines have been associated with cardiometabolic disorders, such as obesity, gestational diabetes, and type 2 diabetes. This study aimed to examine prospective associations of acylcarnitine profiles across gestation with neonatal anthropometry, including birthweight (BW), BW z-score, the sum of skinfolds (SS), body length, and head circumference. We quantified 28 acylcarnitines using electrospray ionization tandem mass spectrometry in plasma collected at gestational weeks 10-14, 15-26, 23-31 and 33-39 among 321 pregnant women from the NICHD Fetal Growth Studies-Singletons and performed latent-class trajectory approach to identify trajectories of acylcarnitines across gestation. We examined the associations of individual acylcarnitines and distinct trajectory groups with neonatal outcomes using weighted generalized linear models adjusting for maternal age, race, education, parity, gestational age of blood collection, and pre-pregnancy BMI. Women showed changes in plasma levels of all acylcartinines across gestation and had at least two significantly distinct group-based trajectories for 32% of acylcartinines. Longitudinally, women with increased C12 levels across gestation (5.7%) had significantly smaller BW (-475 g; 95% CI, -942, -6.79), BW z-score (-0.39, 95% CI, -0.71, -0.06), and length (-1.38, 95% CI, -2.49, -0.27) than those with persistently stable C12 levels during pregnancy (all FDR&lt;0.05). Women with persistently higher levels of C10 (6.1%) or C10:1 (87.4%) had greater sum of skinfolds (4.91, 95%, 0.85, 8.98) than those with lower levels during pregnancy (P&lt;0.05). In conclusion, this study identified that gestational trajectories of C10, C10:1, and C12 acylcarnitine levels were significantly associated with neonatal anthropometry. Further studies are needed to replicate and assess clinical utility of these findings.