Institut Universitaire de Recherche Clinique

We present UCL-MetIsoLib, a publicly accessible high-resolution tandem mass spectrometry (HRMS/MS) library developed for HILIC-based, ion-pairing-free, isomer-resolved metabolomics using a bioinert UHPLC system and the Acquity Premier BEH Amide column. The platform integrates two complementary methods operating under distinct chromatographic conditions (pH 3.5, ESI+; pH 11.0, ESI-), enabling broad metabolic coverage. A total of 334 metabolites are annotated in the library structure, with thiol derivatization incorporated into the extraction protocol to mitigate redox-driven artifacts. Metabolite identification is supported by 245 authentic reference standards and curated according to MSI Level 1 and Level 2 criteria. Validation followed FDA guidelines for bioanalytical method validation across five biological matrices─urine, plasma, tissues, cells, and patient-derived colorectal organoids. The method demonstrated high precision (<15% RSD intra/inter-day) and recovery (85-115% across all QC levels). To demonstrate biological applicability, UCL-MetIsoLib was applied to a case study comparing healthy and colorectal cancer-derived organoids. The method enabled confident annotation of metabolite isomers, including key glycolytic intermediates such as DHAP and GA3P, as well as sugar phosphates from the glycolysis and pentose phosphate pathways. Metabolic alterations were observed in tumor organoids, including accumulation of nucleotide derivatives and shifts in central carbon metabolism. The library is constantly under expansion and is freely available in its latest version at: https://github.com/kserafimov10/UCLMetIsoLib.

Abstract Telomere shortening is a hallmark of aging, yet telomere length (TL) varies considerably among individuals and is strongly influenced by inheritance. In mice, efficient mitochondrial function-characterized by low reactive oxygen species (ROS) production-is critical for telomere elongation during early embryogenesis. Since mitochondrial DNA (mtDNA) encodes several subunits of the electron transport chain, it may influence TL at birth by regulating mitochondrial function in utero . To explore the relationship between mtDNA and TL, we used a transmitochondrial cybrid approach, introducing mitochondria from donor platelets with varying telomere lengths into mtDNA-depleted cells. This revealed an inverse correlation between donor blood TL and mitochondrial ROS levels measured in the resulting cybrids. Under the specific conditions of cybrid formation, which involve a metabolic shift from glycolysis to oxidative phosphorylation, mtDNA variants associated with reduced complex I (CI) activity induced rapid telomere shortening, further implicating mitochondrial metabolism in TL regulation. Notably, this effect was prevented by antioxidant treatment and supplementation with NAD⁺ precursors, supporting a critical role for CI in sustaining PARP1 activity through maintenance of the NAD⁺/NADH balance to preserve telomere integrity under acute oxidative stress. Collectively, these findings suggest that specific mtDNA variants may contribute to the maintenance of long telomeres in humans by enhancing mitochondrial fitness, thereby highlighting potential therapeutic opportunities for mitochondrial replacement strategies. Significance Statement Telomere length at birth influences aging trajectories and disease risk later in life, yet the mechanisms governing this trait remain incompletely understood. Using a transmitochondrial cybrid approach, we show that single-nucleotide variants in the mitochondrial genome of healthy donors directly affect mitochondrial metabolism and reactive oxygen species production. In addition, mitochondrial ROS levels measured in cybrids inversely correlate with blood cell telomere length in donors. Mitochondrial DNA variants associated with reduced complex I activity promote telomere shortening during an i n vitro metabolic shift toward oxidative phosphorylation, an effect that is reversed by antioxidant treatment or NAD⁺ precursor supplementation. Together, these findings establish a direct link between mitochondrial genetics, redox homeostasis, and telomere maintenance in human cells.

Carbohydrate intake remains one of the most influential factors affecting post-meal glucose levels in type 1 diabetes (T1D). To individualize and optimize patient education on carbohydrate counting, it is essential to assess their knowledge of carbohydrate counting. For this purpose, we aimed to produce and validate a questionnaire for French-speaking individuals based on the American AdultCarbQuiz questionnaire (43 items). The translation and cross-cultural adaptation of the American questionnaire were followed by an analysis conducted by patient and diabetologist expert groups. 190 participants living with T1D, Diabetologist expert group. Internal consistency and reliability were verified by administering the adapted French version of the questionnaire to 190 participants living with T1D. Clinical validity was verified by examining the correlation between the questionnaire score and the time in range (TIR) of these participants. Translation and back-translation demonstrated good consistency with the original questionnaire. Typical American food items were replaced with foods commonly consumed in France. All items were validated by both patient and diabetologist experts. After analyzing the responses of 190 participant, seven items were considered non-discriminatory and were therefore removed. Internal consistency, assessed by Cronbach's α, was high, with α = 0.785, 95 CI [0.738-0.826]. Finally, we produced a 36 item French questionnaire named GluciQuizz. TIR correlated with the GluciQuizz score (r = 0.3; p < 0.0001). This study validates a French-language self-administered questionnaire (GluciQuizz), which evaluates different domains of carbohydrate knowledge in a 15-minute quiz for people living with T1D.