OBJECTIVE: Although recent discoveries regarding the biomarkers of newborn screening (NBS) programs by tandem mass spectrometry (MS/MS) highlight the critical need to establish reference intervals (RIs) specifically for preterm infants, no such RIs has been formally published yet. This study addressed the gap by offering a comprehensive set of reference intervals (RIs) for preterm neonates, and illustrating the dynamic changes of each biomarker with age.
METHODS: The NBS data of 199,693 preterm newborns (< 37 weeks of gestation) who met the inclusion and exclusion criteria from the NNSCP database were included in study analysis. The birth weight stratified dynamic trend of each biomarker were captured by their concentrations over age. Reference partitions were determined by the method of Harris and Boyd. RIs, corresponding to the 2.5th and 97.5th percentiles, as well as the 0.5th, 25th, 50th, 75th and 99.5th percentiles were calculated using a non-parametric rank approach.
RESULTS: Increasing birth weight is associated with an elevation in the levels of arginine, citrulline, glycine, leucine and isobarics, methionine, ornithine, phenylalanine, and valine, whereas the levels of alanine, proline and tyrosine decrease. Additionally, two short-chain acylcarnitines (butyrylcarnitine + isobutyrylcarnitine and isovalerylcarnitine + methylbutyrylcarnitine) and a median-chain acylcarnitine (octenoylcarnitine) decrease, while four long-chain acylcarnitines (tetradecanoylcarnitine, palmitoylcarnitine, palmitoleylcarnitine and oleoylcarnitine) increase with increasing birth weight. Age impacts the levels of all MS/MS NBS biomarkers, while sex only affects the level of malonylcarnitine + 3-hydroxybutyrylcarnitine (C3-DC + C4-OH) in very low birth weight preterm neonates.
CONCLUSIONS: The current study developed reference intervals (RIs) specific to birth weight, age, and/or sex for 35 MS/MS biomarkers, which can help in the timely evaluation of the health and disease of preterm neonates.

OBJECTIVE: To explore the clinical characteristics and genetic variants in three children with late-onset Multiple acyl-Coenzyme A dehydrogenase deficiency (MADD type Ⅲ).
METHODS: Clinical data of three children diagnosed with late-onset MADD at the Children\'s Hospital Affiliated to Zhengzhou University between March 2020 and March 2022 were retrospectively analyzed. All children were subjected to whole exome sequencing (WES), and candidate variants were verified by Sanger sequencing. All children had received improved metabolic therapy and followed up for 1 ~ 3 years.
RESULTS: The children had included 2 males and 1 female, and aged from 2 months to 11 years and 7 months. Child 1 had intermittent vomiting, child 2 had weakness in lower limbs, while child 3 had no symptom except abnormal neonatal screening. Tandem mass spectrometry of the three children showed elevation of multiple acylcarnitines with short, medium and long chains. Children 1 and 2 showed increased glutaric acid and multiple dicarboxylic acids by urine Gas chromatography-mass spectrometry (GC-MS) analysis. All children were found to harbor compound heterozygous variants of the ETFDH gene, including a paternal c.1211T>C (p.M404T) and a maternal c.488-22T>G variant in child 1, a paternal c.1717C>T (p.Q573X) and a maternal c.250G>A (p.A84T) variant in child 2, and a paternal c.1285+1G>A and maternal c.629A>G (p.S210N) variant in child 3. As for the treatment, high-dose vitamin B2, levocarnitine and coenzyme Q10 were given to improve the metabolism, in addition with a low fat, hypoproteinic and high carbohydrate diet. All children showed a stable condition with normal growth and development during the follow-up.
CONCLUSIONS: The compound heterozygous variants of the ETFDH gene probably underlay the muscle weakness, remittent vomiting, elevated short, medium, and long chain acylcarnitine, as well as elevated glutaric acid and various dicarboxylic acids in the three children with type Ⅲ MADD.

BACKGROUND: Data suggest malfunctioning mitochondria reduce oxidation and adenosine triphosphate (ATP) production, disrupting insulin signalling. Cytochrome c (CC), acylcarnitine (AC) and citrate synthase (CS) are essential components of the mitochondria machinery and can be used as reliable biomarkers of mitochondrial dysfunction. This study aimed to determine whether mitochondrial biomarkers (AC, CS and CC) are altered in individuals with type 2 diabetes mellitus (T2DM) and to examine the association between these biomarkers and insulin resistance.
METHODS: A cross-sectional observational study that recruited 170 participants (88 with T2DM and 82 without DM) was conducted. Blood samples were collected from the recruits and analysed for levels of fasting glucose (FBG), AC, CS, CC, insulin, total cholesterol, triglycerides (TG), glycated haemoglobin (HbA1c) and magnesium. Blood pressure (BP) and anthropometric characteristics of participants were also taken. Appropriate formulas were used to determine %body fat, body mass index (BMI), waist-to-hip ratio (WHR), the homeostatic model assessment for insulin resistance (HOMA-IR) and insulin sensitivity (HOMA-β).
RESULTS: Patients with T2DM had higher levels of CC, %body fat, FBG, TG, HbA1c, BMI and HOMA-IR than controls (p < 0.05, respectively). Results showed a significant relationship between circulating CC levels versus HOMA-β (r = -0.40, p = 0.001), CS (r = -0.70, p = 0.001) and AC (r = -0.72, p = 0.001) levels in patients with T2DM. The adjusted odds increased in the T2DM patients for VLDL (OR = 6.66, p = 0.002), HbA1c (OR = 6.50, p = 0.001), FPG (OR = 3.17, p = 0.001), TG (OR = 2.36, p = 0.010), being female (OR = 2.09, p = 0.020) and CC (OR = 1.14, p = 0.016).
CONCLUSIONS: Overall, alterations in mitochondrial biomarkers, measured by AC, CC and CS, were observed in people with T2DM and showed a direct relationship with insulin resistance. These findings are potentially significant in Africa, although additional confirmation from a larger cohort is necessary.

Several inherited metabolic fatty acid disorders present with myopathies. Skeletal muscle accounts for 40% of the body and is important for metabolism, exercise, and movement. Muscle energy failure is manifested by metabolic crises with muscle weakness, sometimes associated with muscle fatigue and failure resulting in acute necrosis or rhabdomyolysis/myoglobinuria episodes. Lack of energy leads to muscle necrosis. Other presentations are weakness and myalgias with lipid storage myopathies in the biopsy. The biomarkers of such disorders are acyl-carnitine with various profiles and need to be carefully evaluated to plan supplementary therapy and specific diets. If red flags are not distinctly followed and diagnosed in time they might lead to a metabolic or cardiac failure.

Lipid functions can be influenced by genetics, age, disease states, and lifestyle factors, particularly dietary patterns, which are crucial in diabetes management. Lipidomics is an expanding field involving the comprehensive exploration of lipids from biological samples. In this cross-sectional study, 396 participants from a Mediterranean region, including individuals with type 1 diabetes (T1D), type 2 diabetes (T2D), and non-diabetic individuals, underwent lipidomic profiling and dietary assessment. Participants completed validated food frequency questionnaires, and lipid analysis was conducted using ultra-high-performance liquid chromatography coupled with mass spectrometry (UHPLC/MS). Multiple linear regression models were used to determine the association between lipid features and dietary patterns. Across all subjects, acylcarnitines (AcCa) and triglycerides (TG) displayed negative associations with the alternate Healthy Eating Index (aHEI), indicating a link between lipidomic profiles and dietary habits. Various lipid species (LS) showed positive and negative associations with dietary carbohydrates, fats, and proteins. Notably, in the interaction analysis between diabetes and the aHEI, we found some lysophosphatidylcholines (LPC) that showed a similar direction with respect to aHEI in non-diabetic individuals and T2D subjects, while an opposite direction was observed in T1D subjects. The study highlights the significant association between lipidomic profiles and dietary habits in people with and without diabetes, particularly emphasizing the role of healthy dietary choices, as reflected by the aHEI, in modulating lipid concentrations. These findings underscore the importance of dietary interventions to improve metabolic health outcomes, especially in the context of diabetes management.

In Japan, the promotion of effective use of many wild deer as food resource has been conducted. However, they are not necessarily utilized effectively. Thus, we focused physiologically functional compounds to find characteristics of Sika deer meats (commercially available) obtained from different regions such as Hokkaido, Wakayama, Tokushima, and Miyazaki prefectures in Japan, making it a valuable resource for future studies and applications. The amount of carnosine, anserine, and balenine in muscle of deer from Wakayama prefecture was significantly lower than that in muscle of deer from other prefectures. The differences of amount of imidazole dipeptides in different prefectures seems to be caused by feed, rearing environment, and breed. The amount of carnitine in deer meat from Hokkaido was significantly lower than that in muscle of deer from other prefectures, while the amount of acetyl-carnitine in deer meat from Miyazaki prefectures was significantly higher than that from other prefectures. The amounts of glutamine, ornithine, and 3-methylhistidine in muscles of deer from Wakayama prefectures were significantly higher than those in muscle of deer from other prefectures. These results might be caused by differences in feeding habits, habitat, the muscle types, and subspecies of deer obtained from four regions in Japan.

UNASSIGNED: The co-occurrence of kidney disease in patients with type 2 diabetes (T2D) is a major public health challenge. Although early detection and intervention can prevent or slow down the progression, the commonly used estimated glomerular filtration rate (eGFR) based on serum creatinine may be influenced by factors unrelated to kidney function. Therefore, there is a need to identify novel biomarkers that can more accurately assess renal function in T2D patients. In this study, we employed an interpretable machine-learning framework to identify plasma metabolomic features associated with GFR in T2D patients.
UNASSIGNED: We retrieved 1626 patients with type 2 diabetes (T2D) in Liaoning Medical University First Affiliated Hospital (LMUFAH) as a development cohort and 716 T2D patients in Second Affiliated Hospital of Dalian Medical University (SAHDMU) as an external validation cohort. The metabolite features were screened by the orthogonal partial least squares discriminant analysis (OPLS-DA). We compared machine learning prediction methods, including logistic regression (LR), support vector machine (SVM), random forest (RF), and eXtreme Gradient Boosting (XGBoost). The Shapley Additive exPlanations (SHAP) were used to explain the optimal model.
UNASSIGNED: For T2D patients, compared with the normal or elevated eGFR group, glutarylcarnitine (C5DC) and decanoylcarnitine (C10) were significantly elevated in GFR mild reduction group, and citrulline and 9 acylcarnitines were also elevated significantly (FDR<0.05, FC > 1.2 and VIP > 1) in moderate or severe reduction group. The XGBoost model with metabolites had the best performance: in the internal validate dataset (AUROC=0.90, AUPRC=0.65, BS=0.064) and external validate cohort (AUROC=0.970, AUPRC=0.857, BS=0.046). Through the SHAP method, we found that C5DC higher than 0.1μmol/L, Cit higher than 26 μmol/L, triglyceride higher than 2 mmol/L, age greater than 65 years old, and duration of T2D more than 10 years were associated with reduced GFR.
UNASSIGNED: Elevated plasma levels of citrulline and a panel of acylcarnitines were associated with reduced GFR in T2D patients, independent of other conventional risk factors.

Objective: To explore the relationship between BMI and levels of plasma amino acids and acylcarnitines in Chinese adults. Methods: Based on 2 182 individuals with targeted mass spectrometry metabolomic measurements from the first resurvey of the China Kadoorie Biobank, we assessed the linear and nonlinear associations between BMI and plasma levels of 20 amino acids and 40 acylcarnitines using linear regression models and restricted cubic spline models, and identified BMI-related metabolic pathways. We conducted one-sample Mendelian randomization (MR) with BMI genetic risk scores as the instrumental variable further to explore the potential causal relationships between BMI and 20 amino acids and 40 acylcarnitines, and tested for horizontal pleiotropy using the MR-Egger method. Results: Observational analyses found that BMI was associated with increased plasma levels of 3 branched-chain amino acids (isoleucine, leucine, and valine), 2 aromatic amino acids (phenylalanine and tyrosine), 3 other amino acids (cysteine, glutamate, lysine), and 7 acylcarnitines (C3, C4, C5, C10, C10:1, C14, and C16), and with decreased circulating levels of asparagine, serine, and glycine. Pathway analysis identified 7 BMI-related amino acids metabolic pathways (false discovery rate corrected all P<0.05), including branched-chain amino acids and aromatic amino acids biosynthesis, glutathione metabolism, etc. BMI showed a nonlinear relationship with leucine, valine, and threonine, and a linear relationship with other amino acids and acylcarnitines. One-sample MR analyses revealed that BMI was associated with elevated levels of tyrosine and 4 acylcarnitines [C5-DC(C6-OH), C5-M-DC, C12-DC, and C14], with tyrosine and acylcarnitine C14 positively correlated with BMI in both observational [the β values (95%CIs) were 0.057 (0.044-0.070) and 0.018 (0.005-0.032), respectively] and One-sample MR analyses [the β values (95%CIs) were 0.102 (0.035-0.169) and 0.104 (0.036-0.173), respectively]. The MR analyses of the current study satisfied the 3 core assumptions of instrumental variable. Conclusions: BMI was associated with circulating 11 amino acids and 7 acylcarnitines in Chinese adults, involving several pathways such as branched-chain amino acid and aromatic amino acid metabolism, fatty acid metabolism, and oxidative stress. There may be a causal relationship between BMI and tyrosine and acylcarnitine C14.
目的： 探讨中国成年人BMI与血浆氨基酸和酰基肉碱水平的关联。 方法： 基于中国慢性病前瞻性研究（CKB）第一次重复调查中2 182名具有靶向质谱代谢组检测的研究对象，采用多元线性回归模型和限制性立方样条模型分析BMI与血浆20种氨基酸和40种酰基肉碱的线性和非线性关联，并识别BMI相关的代谢通路。以BMI的遗传风险评分作为工具变量，采用单样本孟德尔随机化（MR）分析进一步探索BMI与20种氨基酸和40种酰基肉碱的潜在因果关联，并使用MR-Egger法检验水平多效性。 结果： 观察性分析结果显示，BMI与3种支链氨基酸（异亮氨酸、亮氨酸和缬氨酸）、2种芳香族氨基酸（苯丙氨酸和酪氨酸）、3种其他氨基酸（半胱氨酸、谷氨酸、赖氨酸）以及7种酰基肉碱（C3、C4、C5、C10、C10：1、C14和C16）的血浆水平升高相关，与天冬酰胺、丝氨酸和甘氨酸水平降低相关。通路分析发现7个与BMI相关的氨基酸代谢通路（错误发现率校正后均P<0.05），包括支链氨基酸和芳香族氨基酸的生物合成、谷胱甘肽代谢等。BMI与亮氨酸、缬氨酸和苏氨酸呈非线性关联，BMI与其他氨基酸和酰基肉碱均呈线性关联。单样本MR分析发现BMI与酪氨酸和4种酰基肉碱［C5-DC（C6-OH）、C5-M-DC、C12-DC和C14］水平升高相关，其中酪氨酸和酰基肉碱C14在观察性分析［β值（95%CI）分别为0.057（0.044~0.070）和0.018（0.005~0.032）］和单样本MR分析［β值（95%CI）分别为0.102（0.035~0.169）和0.104（0.036~0.173）］中均与BMI呈显著正相关。经检验，本研究的MR分析满足工具变量的3个核心假设。 结论： 中国成年人BMI与血浆11种氨基酸和7种酰基肉碱水平相关，涉及支链氨基酸和芳香族氨基酸代谢、脂肪酸代谢和氧化应激等多种途径，BMI与酪氨酸和酰基肉碱C14可能存在因果关联。.

Obesity is a complex disease associated with augmented risk of metabolic disorder development and cellular dysfunction in various species. The goal of the present study was to investigate the impacts of obesity on the metabolic health of old mares as well as test the ability of diet supplementation with either a complex blend of nutrients designed to improve equine metabolism and gastrointestinal health or L-carnitine alone to mitigate negative effects of obesity. Mares (n = 19, 17.9 ± 3.7 years) were placed into one of three group: normal-weight (NW, n = 6), obese (OB, n = 7) or obese fed a complex diet supplement for 12 weeks (OBD, n = 6). After 12 weeks and completion of sample collections, OB mares received L-carnitine alone for an additional 6 weeks. Obesity in mares was significantly associated with insulin dysregulation, reduced muscle mitochondrial function, and decreased skeletal muscle oxidative capacity with greater ROS production when compared to NW. Obese mares fed the complex diet supplement had better insulin sensivity, greater cell lipid metabolism, and higher muscle oxidative capacity with reduced ROS production than OB. L-carnitine supplementation alone did not significantly alter insulin signaling, but improved lipid metabolism and muscle oxidative capacity with reduced ROS. In conclusion, obesity is associated with insulin dysregulation and altered skeletal muscle metabolism in older mares. However, dietary interventions are an effective strategy to improve metabolic status and skeletal muscle mitochondrial function in older mares.

OBJECTIVE: This study aimed to develop a novel exfoliating material with high efficacy and low irritation by synthesizing the Mandelic acid_Carnitine ion pairing complex (M_C complex) and evaluating its exfoliating properties. Additionally, the study assessed the skin improvement effects of the M_C complex through clinical evaluations.
METHODS: The M_C complex was synthesized in a 1:1 molar ratio of Mandelic acid and Carnitine. Structural characterization was performed using dynamic light scattering and Fourier-transform infrared spectroscopy. Exfoliating efficacy was evaluated on porcine skin, and clinical assessments were conducted on human subjects to measure various skin improvement parameters.
RESULTS: The formation of the M_C complex was confirmed through particle size analysis, zeta-potential measurements, and FT-IR spectroscopy. The M_C complex demonstrated superior exfoliating efficacy compared to Mandelic acid alone, especially at pH 4.5. Clinical evaluations showed significant improvements in blackheads, whiteheads, pore volume, depth, density, count, and affected area, as well as skin texture. No adverse reactions were observed.
CONCLUSIONS: The M_C complex exhibits high exfoliating efficacy and minimal irritation, making it a promising cosmetic ingredient for improving skin health. These findings support its potential as a low-irritation exfoliating material under mildly acidic conditions, contributing to overall skin health enhancement.