Pediatric reference values of NT-proBNP and Galectin-3 based on a French cohort.

BACKGROUND: In pediatric cardiology, the fact that some new biomarkers have assay-specific normal values has to be considered for correct clinical decisions. The current study aimed to provide age-adjusted normative values for NT-proBNP and Galectin-3 using the Abbott immunoassay system from a prospective French pediatric cohort sera collection and to validate our data for NT-proBNP on a second retrospective cohort. METHODS: We analyzed 283 consecutive samples for NT-proBNP and 140 samples for Galectin-3 collected from apparently healthy children (0-18 years) with outpatient treatment at our institution (Hôpital Necker-Enfants malades, Paris, France) during 24 months. RESULTS: For NT-proBNP and Galectin-3, we establish four age partitions, respectively two (<2 years / >2 years) and establish upper reference values and their 90 % CI for each biomarker (Galectin-3 (ng/mL): 56 [44-70] / 26 [23-29]). We evaluated the diagnostic performance of our upper reference values of NT-proBNP on a retrospective cohort (n = 428) with positive predictive value of 0.92. CONCLUSIONS: Using Abbott immunoassay system, we report age-specific reference values for NT-proBNP and for the first time for Galectin-3 in a healthy French pediatric cohort. These data call for larger cohort studies to define more robustly percentiles and diagnostic performance for NT-proBNP.

Fasting upregulates the monocarboxylate transporter MCT1 at the rat blood-brain barrier through PPAR δ activation.

BACKGROUND: The blood-brain barrier (BBB) is pivotal for the maintenance of brain homeostasis and it strictly regulates the cerebral transport of a wide range of endogenous compounds and drugs. While fasting is increasingly recognized as a potential therapeutic intervention in neurology and psychiatry, its impact upon the BBB has not been studied. This study was designed to assess the global impact of fasting upon the repertoire of BBB transporters. METHODS: We used a combination of in vivo and in vitro experiments to assess the response of the brain endothelium in male rats that were fed ad libitum or fasted for one to three days. Brain endothelial cells were acutely purified and transcriptionaly profiled using RNA-Seq. Isolated brain microvessels were used to assess the protein expression of selected BBB transporters through western blot. The molecular mechanisms involved in the adaptation to fasting were investigated in primary cultured rat brain endothelial cells. MCT1 activity was probed by in situ brain perfusion. RESULTS: Fasting did not change the expression of the main drug efflux ATP-binding cassette transporters or P-glycoprotein activity at the BBB but modulated a restrictive set of solute carrier transporters. These included the ketone bodies transporter MCT1, which is pivotal for the brain adaptation to fasting. Our findings in vivo suggested that PPAR δ, a major lipid sensor, was selectively activated in brain endothelial cells in response to fasting. This was confirmed in vitro where pharmacological agonists and free fatty acids selectively activated PPAR δ, resulting in the upregulation of MCT1 expression. Moreover, dosing rats with a specific PPAR δ antagonist blocked the upregulation of MCT1 expression and activity induced by fasting. CONCLUSIONS: Altogether, our study shows that fasting affects a selected set of BBB transporters which does not include the main drug efflux transporters. Moreover, we describe a previously unknown selective adaptive response of the brain vasculature to fasting which involves PPAR δ and is responsible for the up-regulation of MCT1 expression and activity. Our study opens new perspectives for the metabolic manipulation of the BBB in the healthy or diseased brain.

Targeting TXNIP in endothelial progenitors mitigates IL-8-induced neutrophil recruitment under metabolic stress.

BACKGROUND: This study explores the potential role of Thioredoxin-interacting protein (TXNIP) silencing in endothelial colony-forming cells (ECFCs) within the scope of age-related comorbidities and impaired vascular repair. We aim to elucidate the effects of TXNIP silencing on vasculogenic properties, paracrine secretion, and neutrophil recruitment under conditions of metabolic stress. METHODS: ECFCs, isolated from human blood cord, were transfected with TXNIP siRNA and exposed to a high glucose and ß-hydroxybutyrate (BHB) medium to simulate metabolic stress. We evaluated the effects of TXNIP silencing on ECFCs' functional and secretory responses under these conditions. Assessments included analyses of gene and protein expression profiles, vasculogenic properties, cytokine secretion and neutrophil recruitment both in vitro and in vivo. The in vivo effects were examined using a murine model of hindlimb ischemia to observe the physiological relevance of TXNIP modulation under metabolic disorders. RESULTS: TXNIP silencing did not mitigate the adverse effects on cell recruitment, vasculogenic properties, or senescence induced by metabolic stress in ECFCs. However, it significantly reduced IL-8 secretion and consequent neutrophil recruitment under these conditions. In a mouse model of hindlimb ischemia, endothelial deletion of TXNIP reduced MIP-2 secretion and prevented increased neutrophil recruitment induced by age-related comorbidities. CONCLUSIONS: Our findings suggest that targeting TXNIP in ECFCs may alleviate ischemic complications exacerbated by metabolic stress, offering potential clinical benefits for patients suffering from age-related comorbidities.