Publications by authors named "Gabriel Richard"

Article Synopsis
  • The study investigates how the heart and kidneys utilize ketones as an energy source using a tracer called carbon-11 acetoacetate (C-AcAc) in 10 healthy adults under different fasting and feeding conditions.
  • Two models were used to assess metabolism, with the heart following a two-compartment model and the kidneys a three-compartment model; plasma ketone levels increased significantly after consuming D-beta-hydroxybutyrate (D-BHB).
  • Findings reveal that C-AcAc uptake differs with age in both organs, and that D-BHB alters the body's response to meals, suggesting potential for using this methodology in future research on heart and kidney health in various conditions.
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Background: Ketone metabolism has been studied using positron emission tomography (PET) with the radiotracers [C]acetoacetate and [C]β-hydroxybutyrate. However, whether these two radiotracers actually yield equivalent estimates of cerebral and myocardial ketone metabolism has not yet been investigated. This study aimed to investigate and compare the kinetics of both tracers in the brain and heart of healthy rats under varying levels of circulating ketones at baseline and after a single-dose exogenous ketone ester (KE) supplement.

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BACKGROUNDIn type 1 diabetes (T1D), impaired insulin sensitivity may contribute to the development of diabetic kidney disease (DKD) through alterations in kidney oxidative metabolism.METHODSYoung adults with T1D (n = 30) and healthy controls (HCs) (n = 20) underwent hyperinsulinemic-euglycemic clamp studies, MRI, 11C-acetate PET, kidney biopsies, single-cell RNA-Seq, and spatial metabolomics to assess this relationship.RESULTSParticipants with T1D had significantly higher glomerular basement membrane (GBM) thickness compared with HCs.

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Recombinase-activating gene (RAG)-deficient SCID patients lack B and T lymphocytes due to the inability to rearrange immunoglobulin and T cell receptor genes. The two genes act as a required dimer to initiate gene recombination. Gene therapy is a valid treatment alternative for RAG-SCID patients who lack a suitable bone marrow donor, but developing such therapy for RAG1/2 has proven challenging.

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Article Synopsis
  • Regulators and industry experts are looking for better ways to assess the cancer-causing potential of gene therapies, as current methods may not be sufficient.
  • A meeting in London in March 2023 brought together specialists to reach a consensus on key themes such as vector genotoxicity, uncertainty sources, and appropriate toxicological endpoints for gene therapy evaluation.
  • The recommendations from this meeting aim to guide the creation of new regulatory guidelines for the nonclinical toxicological assessment of gene therapy products.
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  • Citizen science video games help people contribute to science, but most are aimed at gamers who already want to help, missing out on many others.
  • Borderlands Science (BLS) is a new project that mixes science tasks into a popular video game, making it fun and easy for millions of gamers to participate.
  • Since it started in April 2020, over 4 million players have solved huge science puzzles, helping scientists improve their research on human microbiomes.
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Rationale & Objective: In this pilot study, we hypothesized that autosomal dominant polycystic kidney disease (ADPKD) is characterized by impaired kidney oxidative metabolism that associates with kidney size and cyst burden.

Study Design: Cross-sectional study.

Setting & Participants: Twenty adults with ADPKD (age, 31±6 years; 65% women; body mass index [BMI], 26.

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Aim: Pharmacological stimulation of human brown adipose tissue (BAT) has been hindered by ineffective activation or undesirable off-target effects. Oral administration of the maximal allowable dose of mirabegron (200 mg), a β-adrenergic receptor (β-AR) agonist, has been effective in stimulating BAT thermogenesis and whole-body energy expenditure. However, this has been accompanied by undesirable cardiovascular effects.

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In rodents, loss of estradiol (E) reduces brown adipose tissue (BAT) metabolic activity. Whether E impacts BAT activity in women is not known. BAT oxidative metabolism was measured in premenopausal ( = 27; 35 ± 9 yr; body mass index = 26.

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Ketones are alternative energy substrates for the heart and kidney but no studies have investigated their metabolism simultaneously in both organs in humans. The present double tracer positron emission tomography (PET) study evaluated the organ distribution and basal kinetic rates of the radiolabeled ketone, C-acetoacetate (C-AcAc), in the heart and kidney compared to C-acetate (C-Ac), which is a well-validated metabolic radiotracer. Both tracers were highly metabolized by the left ventricle and the renal cortex.

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Spinal muscular atrophy is an autosomal recessive disease resulting in motor neuron degeneration and progressive life-limiting motor deficits when untreated. Onasemnogene abeparvovec is an adeno-associated virus serotype 9-based gene therapy that improves survival, motor function, and motor milestone achievement in symptomatic and presymptomatic patients. Although the adeno-associated virus genome is maintained as an episome, theoretical risk of tumorigenicity persists should genomic insertion occur.

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Article Synopsis
  • Diets high in added sugars are linked to metabolic diseases and can alter the microbiome, which might affect brown adipose tissue (BAT) function.
  • This study aimed to explore how high-glucose and high-fructose diets influence BAT's ability to generate heat and how these diets impact the gut microbiome.
  • Results revealed that high-fructose diets decrease BAT's glucose uptake, but do not affect its thermogenesis or change the gut microbiome, suggesting early metabolic issues from excessive fructose consumption.
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Background: The graded exercise treadmill stress test (GXT) is among the most frequently performed tests in cardiology. The COVID-19 pandemic led many healthcare facilities to require patients to wear a mask during the test. This study evaluated the effect of wearing a surgical face mask on exercise capacity and perceived exertion.

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Decision-making skills are essential to successful performance. To train them, coaches frequently use video replays to show their athletes how to best respond when facing specific situations. Recently, it has been shown that presenting the videos in virtual reality (VR) led to enhanced transfer, from the laboratory to the playing field, compared to when the videos were presented on a standard computer screen (CS).

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The advent of deep-learning has set new standards in an array of image translation applications. At present, the use of these methods often requires computer programming experience. Non-commercial programs with graphical interface usually do not allow users to fully customize their deep-learning pipeline.

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  • - The study investigates how T cell exhaustion (a state where T cells lose effectiveness against tumors) affects immunity and responses to immunotherapy in chronic lymphocytic leukemia (CLL).
  • - Researchers identified different subsets of CD8 T cells, noting that specific signaling pathways (IL-10R and STAT3) influence the balance between exhausted and functional T cells, impacting tumor progression.
  • - Findings suggest that low levels of IL-10 or disruptions in IL-10R-STAT3 signaling lead to increased exhausted T cells, which correlate with worse patient outcomes in CLL and breast cancer, highlighting potential targets for improving immunotherapy.
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The obesity pandemic increasingly causes morbidity and mortality from type 2 diabetes, cardiovascular diseases and many other chronic diseases. Fat cell size (FCS) predicts numerous obesity-related complications such as lipid dysmetabolism, ectopic fat accumulation, insulin resistance, and cardiovascular disorders. Nevertheless, the scarcity of systematic literature reviews on this subject is compounded by the use of different methods by which FCS measurements are determined and reported.

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Lipocalin 2 (LCN2) is a secreted glycoprotein with roles in multiple biological processes. It contributes to host defense by interference with bacterial iron uptake and exerts immunomodulatory functions in various diseases. Here, we aimed to characterize the function of LCN2 in lung macrophages and dendritic cells (DCs) using Lcn2-/- mice.

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Purpose: Determine if dynamic contrast enhanced (DCE) -MRI and/or 68 gallium 1,4,7,10-tetraazacyclododecane N, N', N″, N‴-tretraacetic acid ( Ga-DOTA) positron emission tomography (PET) can assess perfusion in rat brown adipose tissue (BAT). Evaluate changes in perfusion between cold-stimulated and heat-inhibited BAT. Determine if the C-acetate pharmacokinetic model can be constrained with perfusion information to improve assessment of BAT oxidative metabolism.

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Aims: Cell-based biological pacemakers aim to overcome limitations and side effects of electronic pacemaker devices. We here developed and tested different approaches to achieve nodal-type differentiation using human adipose- and bone marrow-derived mesenchymal stem cells (haMSC, hbMSC).

Main Methods: haMSC and hbMSC were differentiated using customized protocols.

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Chronic lymphocytic leukemia (CLL) is associated with substantial alterations in T-cell composition and function. However, the role of T-cells in CLL remains largely controversial. Here, we utilized the Eµ-TCL1 mouse model of CLL as well as blood and lymph node samples of CLL patients to investigate the existence of anti-tumoral immune responses in CLL, and to characterize involved immune cell populations.

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Article Synopsis
  • SLAMF1 is an immune receptor that helps activate signaling pathways in immune cells, essential for their function.
  • This study highlights SLAMF1's role in enabling TLR4 to induce interferon β and enhance the ability of human macrophages to kill Gram-negative bacteria.
  • The research also reveals that SLAMF1 assists in moving TRAM to the phagosomes where bacteria are attacked, suggesting it could be a target for controlling inflammatory responses in humans.
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High-throughput sequencing technologies have exposed the possibilities for the in-depth evaluation of T-cell receptor (TCR) repertoires. These studies are highly relevant to gain insights into human adaptive immunity and to decipher the composition and diversity of antigen receptors in physiological and disease conditions. The major objective of TCR sequencing data analysis is the identification of V, D and J gene segments, complementarity-determining region 3 (CDR3) sequence extraction and clonality analysis.

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Bacterial conjugation is a mechanism of horizontal DNA transfer. The relaxase TrwC of the conjugative plasmid R388 cleaves one strand of the transferred DNA at the gene, covalently attaches to it, and leads the single-stranded DNA (ssDNA) into the recipient cell. In addition, TrwC catalyzes site-specific integration of the transferred DNA into its target sequence present in the genome of the recipient bacterium.

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Positive-stranded RNA viruses, such as hepatitis C virus (HCV), assemble their viral replication complexes by remodeling host intracellular membranes to a membranous web. The precise composition of these replication complexes and the detailed mechanisms by which they are formed are incompletely understood. Here we show that the human immunity-related GTPase M (IRGM), known to contribute to autophagy, plays a previously unrecognized role in this process.

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