Data on cross‐neutralization of the SARS‐CoV‐2 omicron variant more than 1 year after SARS‐CoV‐2 infection are urgently needed, especially in children, to predict the likelihood of reinfection and to guide vaccination strategies. In a prospective observational cohort study, we evaluated live‐virus neutralization of the SARS‐CoV‐2 omicron (BA.1) variant in children compared with adults 14 months after mild or asymptomatic wild‐type SARS‐CoV‐2 infection. We also evaluated immunity to reinfection conferred by previous infection plus COVID‐19 mRNA vaccination. We studied 36 adults and 34 children 14 months after acute SARS‐CoV‐2 infection. While 94% of unvaccinated adults (16/17) and children (32/34) neutralized the delta (B.1.617.2) variant, only 1/17 (5.9%) unvaccinated adults, 0/16 (0%) adolescents and 5/18 (27.8%) children <12 years of age had neutralizing activity against omicron (BA.1). In convalescent adults, one or two doses of mRNA vaccine increased delta and omicron neutralization 32‐fold, similar to a third mRNA vaccination in uninfected adults. Neutralization of omicron was 8‐fold lower than that of delta in both groups. In conclusion, our data indicate that humoral immunity induced by previous SARS‐CoV‐2 wild‐type infection more than 1 year ago is insufficient to neutralize the current immune escape omicron variant.

This study explores the potential of ¹H-NMR spectroscopy-based metabolic profiling in various biofluids as a diagnostic and predictive modality to assess disease severity in individuals with 5q spinal muscular atrophy. A total of 213 biosamples (urine, plasma, and CSF) from 153 treatment-naïve patients with SMA across five German centers were analyzed using ¹H-NMR spectroscopy. Prediction models were developed using machine learning algorithms which enabled the patients with SMA to be grouped according to disease severity. A quantitative enrichment analysis was employed to identify metabolic pathways associated with disease progression. The results demonstrate high sensitivity (84–91%) and specificity (91–94%) in distinguishing treatment-naïve patients with SMA from controls across all biofluids. The urinary and plasma profiles differentiated between early-onset (type I) and later-onset (type II/III) SMA with over 80% accuracy. Key metabolic differences involved alterations in energy and amino acid metabolism. This study suggests that ¹H-NMR spectroscopy based metabolic profiling may be a promising, non-invasive tool to identify patients with SMA and for severity stratification, potentially complementing current diagnostic and prognostic strategies in SMA management.

Very preterm infants with immature kidneys exhibit high vulnerability to acute kidney injury (AKI). While AKI is associated with adverse outcomes, serum-creatinine-based diagnostics prove unreliable in early risk assessment of kidney damage. This pilot study investigated ¹H-NMR spectroscopy-based metabolomics for the identification of very-low-birth-weight (VLBW < 1500 g) infants at risk of AKI before and during indomethacin treatment for patent ductus arteriosus (PDA). Longitudinal urine samples (0 h, 12 h, 36 h, 84 h, 120 h, 14 d, 28 d) from 12 VLBW infants receiving indomethacin for hemodynamically significant PDA were analyzed by ¹H-NMR spectroscopy. In total, 150 urinary metabolites were annotated and single-metabolite and multivariate analyses were performed. At 36 h after treatment initiation, three patients (25%) developed AKI (KDIGO criteria). Principal component analysis (PCA) revealed significant differences in urinary metabolic profiles between the AKI and non-AKI groups 12 h after indomethacin initiation. Before treatment, five metabolites were significantly lower in the AKI group: adenine, creatine, dimethylglycine, 1-methylnicotinamide, and methylmalonic acid. Urinary creatine/creatinine (AUC 0.97) and 1-methylnicotinamide/creatinine (AUC 0.93) exhibited promising prognostic accuracy for the prediction of AKI. 1-methylnicotinamide/creatinine concentrations remained persistently reduced during the study. In conclusion, urinary metabolomics, particularly creatine and 1-methylnicotinamide levels, may serve as valuable non-invasive biomarkers for identifying VLBW infants at risk of AKI.

Background and Aims: Pathogenic variants in neuroblastoma amplified sequence ( NBAS ) gene causes infantile liver failure type 2 (IFLS2; MIM 616483), characterised by recurrent episodes of liver failure triggered by febrile infections. The underlying pathophysiological mechanisms remain incompletely understood. With this work we try to shed light on the pathomechanism and propose a potential therapeutic option. Methods: For in vitro analyses, human skin fibroblasts were obtained from three individuals with ILFS2 and one healthy control. Cells were cultivated at 37°C or 40°C. Western blots were performed to assess NBAS protein and its interaction partners. Furthermore, immunofluorescence and electron microscopy were used to examine morphological changes associated with endoplasmic reticulum (ER) stress. Apoptosis was measured using flow cytometry. The effects of N ‐acetylcysteine (NAC) treatment were analysed not only in cultured fibroblasts but also in vivo retrospectively in 16 affected individuals. Results: We demonstrate that elevated temperature induces ER stress in fibroblasts from individuals with NBAS variants, leading to increased reactive oxygen species (ROS) production and apoptosis. Treatment with the antioxidant NAC, an established therapeutic in acetaminophen‐induced liver failure, effectively mitigated oxidative stress and reduced apoptosis in vitro. In a retrospective clinical analysis, there was a trend that NAC treatment was associated with reduced severity of hepatic crises, suggesting a potential therapeutic benefit. Conclusions: Our findings link fever‐induced ER stress, ROS accumulation, and apoptosis to the pathogenesis of liver failure in NBAS deficiency. NAC attenuates these cellular stress responses and may represent a promising supportive treatment option in NBAS‐associated liver failure.

Interpretation of pharmacometabolomics results, aiming particularly at biomarker (sets) discovery for drug exposure, remains a major challenge. The metabotyping of drug exposure depends on resolution of specific metabolomics techniques and comprises individual metabolic phenotypes (“metabotypes”), disease-, drug- and microbiome-specific patterns, as well as conditional metabolic states (e. g. fasting). In this clinical trial with 16 healthy participants, an exploratory objective was to evaluate the untargeted urinary metabolomics of voriconazole, administered in four single doses, using proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Voriconazole is a second-generation triazole and a potent inhibitor of drug-metabolizing enzymes such as cytochrome P450 (CYP) isozymes CYP3A4 and CYP2C19. Therefore, identification of metabolites reflecting acute CYP3A4 inhibition was of particular interest. On two treatment days without and with voriconazole (with background microdosed midazolam and omeprazole administration for CYP3A4 and CYP2C19 phenotyping, respectively), spot urine was collected after overnight fasting (predose) and 4 h later (postdose fasting). In the postdose versus predose fingerprints, most changes at the annotated metabolite level were attributable to fasting metabolomics or potential confounders. ¹H-NMR spectroscopy identified neither a short-term voriconazole-specific signature nor patterns or metabolites potentially reflecting acute CYP3A4 inhibition. Our study emphasizes crucial significance of strict standardization of fasting time and minimization of confounder influences by clinical trial design as well as selection of adequate baselines and high-resolution analytical techniques in pharmacometabolomics research, especially for biomarker discovery.

Background and Aims: Wilson's disease (WD) is a genetic disorder of copper metabolism in which early diagnosis remains challenging, particularly in acute liver failure (ALF). Relative exchangeable copper (REC) and exchangeable copper (CuEXC) are emerging biomarkers for diagnosis and monitoring, but data from larger cohorts are limited. This monocentric retrospective cohort study evaluated the diagnostic accuracy of REC in WD patients, including adult ALF and assessed the utility of CuEXC during monitoring. Methods: 299 paediatric/adult patients with liver disease were analysed; 215 had confirmed WD (Leipzig score ≥ 4). Clinical data, parameters of copper metabolism and liver function tests were collected. REC was analysed in the full cohort. CuEXC was evaluated longitudinally at three standardized timepoints over 12 months in treated adult WD patients and compared with 24‐h urinary copper excretion (UCE) after 48‐h treatment interruption. Results: REC demonstrated excellent diagnostic accuracy with an AUC of 0.955 (sensitivity 88.4%, specificity 91.7%). In adult ALF, REC perfectly discriminated WD ( n = 2/2, 100%) from other causes. CuEXC declined significantly in therapy‐naïve patients and differentiated these from very stable patients, but showed limited discrimination between stable versus unstable patients during median follow‐up. UCE off‐treatment showed parallel trajectories to CuEXC. Conclusions: REC is a highly accurate diagnostic biomarker for WD, including adult ALF. CuEXC is useful to characterize initial treatment response and copper control, but its role as a routine monitoring biomarker between stable and unstable patients remains uncertain and requires prospective validation, whereas UCE remains as a robust follow‐up parameter in these patients.