Ecophysiological responses of Seriatopora hystrix (Dana, 1846) to short-term hypo- and hypersaline stress

Coral reefs are considered one of the most biodiverse marine ecosystems on the planet. Coral reefs host a large and various community of organisms such as fishes, echinoderms, plankton, etc. The coral reef is a perfect example of the Darwin Paradox, i.e. it has a high productivity when the available nutrients are low (oligotrophic seawater). Coral reefs are threatened by several stressors. Most of these stressors are directly and indirectly linked to anthropogenic factors such as anthropogenic enrichment, overfishing, climate change, etc. Salinity is another stressor of the coral reef balance. The number of tropical storms and hurricanes has strongly increased over the past decades. These climatic events therefore induce a sharp decrease in salinity a couple of days after their occurrence. Moreover, the desalination industry is a new salinity stressor. Saltwater is desalinised to produce fresh water mainly for crop irrigation. A coral reef mesocosm has been used to study the impact of the hyposaline and hypersaline stress on Seriatopora hystrix (Dana 1846), a hermatypic scleractinian species. Three salinity states have been selected: 28 (hyposaline stress), 35 (control) and 42 (hypersaline stress). These states have been kept constant for 7 days. In each condition stress, we have observed a discoloration of corals (not a bleaching), a decline in growth rate, calcification rate and respiration rate. The hypersaline stress reduces more strongly the growth rate that hyposaline stress. The growth comes back to the initial state 3 weeks after the experiment. This experiment could suggest that salinity is an important environmental variable for the coral reef. The variation of salinity, even low and a short duration impacts negatively S.hystrix

Does the 1H-NMR Plasma Metabolome Reflect the Host-Tumor Interactions in Human Breast Cancer?

peer reviewedBreast cancer (BC) is the most common diagnosed cancer and the leading cause of cancer death in women worldwide. There is an obvious need for a better understanding of BC biology. Alterations in the serum metabolome of BC patients have been identified but their clinical significance remains elusive. We evaluated by 1H-Nuclear Magnetic Resonance (1H-NMR) spectroscopy, filtered plasma metabolome of 50 early (EBC) and 15 metastatic BC (MBC) patients. Using Principal Component Analysis, Partial Least-Squares Discriminant Analysis and Hierarchical Clustering we show that plasma levels of glucose, lactate, pyruvate, alanine, leucine, isoleucine, glutamate, glutamine, valine, lysine, glycine, threonine, tyrosine, phenylalanine, acetate, acetoacetate, β-hydroxy-butyrate, urea, creatine and creatinine are modulated across patients clusters. In particular lactate levels are inversely correlated with the tumor size in the EBC cohort (Pearson correlation r=-0.309; p=0.044). We suggest that, in BC patients, tumor cells could induce modulation of the whole patient's metabolism even at early stages. If confirmed in a lager study these observations could be of clinical importance

Hepatic and renal toxicity induced by TiO2 nanoparticles in rats : a morphological and metabonomic study

peer reviewe

Les mécanismes d'assistance visant à favoriser l'accès aux assurances de personnes pour les candidats présentant un risque accru

Analyse des différents mécanismes permettant d'aider les personnes présentant un risque aggravé à souscrire à une assurance de personne.Master [120] en droit, Université catholique de Louvain, 2017La diffusion de ce mémoire n'est pas autorisée par l'institutio

Metabonomic profiling of chronic intermittent hypoxia in a mouse model

Chronic intermittent hypoxia (ChIH) is a dominant feature of obstructive sleep apnoea (OSA) and is associated to metabolic alterations and oxidative stress (OS). Although management of OSA is well established, the research of new biomarkers that are independent of confounding factors remains necessary to improve the early detection of comorbidity and therapeutic follow-up. In this study, the urinary metabonomic profile associated to intermittent hypoxia was evaluated in a mouse model. When exposed to intermittent hypoxia, animals showed a significant alteration in energy metabolism towards anaerobic pathways and signs of OS imbalance. A compensatory response was observed over time. Our data also indicates an excess production of vitamin B3, liver function modulations and a stimulation of creatine synthesis which could be used to evaluate the ChIH repercussions. As well, TMAO and allantoin could constitute interesting biomarker candidates, respectively in the context of cardiovascular risk and OS associated to OSA.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Sustained intermittent hypoxemia induces adiponectin oligomers redistribution and a tissue-specific modulation of adiponectin receptor in mice

Introduction: Hypoxemia is a critical component of several respiratory diseases and is known to be involved in the processes underlying co-morbidities associated to such disorders, notably at the cardiovascular level. Circulating level of Adiponectin (Ad), known as a metabolic regulator and cardio-protective hormone was previously suggested to be reduced by hypoxia but consequences of such variation are unclear. The evaluation of the specific effect of hypoxemia on Ad forms and receptors could improve the understanding of the involvement of Ad axis in hypoxemia-related diseases. Methods: Ad-pathway components were investigated in a murine model of sustained intermittent hypoxemia (FiO2 10%, 8 h/day, 35 days). Results: Sustained intermittent hypoxemia (SIH) induced a redistribution of Ad multimers in favor of HMW forms, without change in total plasmatic level. Mice submitted to hypoxia also exhibited tissue-specific modification of adiporeceptor (AdipoR) protein level without mRNA expression change. A decreased AdipoR2 abundance was observed in skeletal muscle and heart whereas AdipoR1 level was only reduced in muscle. No change was observed in liver regarding AdipoR. Lipid profile was unchanged but glucose tolerance increased in hypoxemic mice. Conclusion: Sustained intermittent hypoxemia, per se, modify Ad oligomerization state as well as AdipoR protein abundance in a tissue-specific way. That suggests alteration in Ad-dependant pathways in pathological conditions associated to SIH. Investigation of Ad-pathway components could therefore constitute useful complementary criteria for the clustering of patients with hypoxemia-related diseases and management of co-morbidities, as well as to develop new therapeutic strategies.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Metabonomics: On the road to detect diagnostic biomarkers in endemic (Balkan) nephropathy. evaluation in a retrospective pilot project

Introduction: Endemic (Balkan) Nephropathy is a chronic renal disease mainly affecting rural populations in the valleys of the Danube. In the absence of renal replacement therapy, it leads to fatal kidney failure and is significantly associated with upper urothelial carcinoma. Bread poisoning with aristolochic acids is now widely accepted. The source of this toxic substance is considered to be Aristolochia clematitis, a perennial plant that invades farming fields. The poisoning with aristolochic acids was suggested when clinical and histopathological changes similar to those observed in the Balkan patients were reported in several cases of nephropathy in Belgian patients unintentionally exposed to aristolochic acids during a Chinese herbs diet. Those clinical and histopathological features were then reproduced in laboratory experimental models. Methods: Using metabonomics, an emerging dynamic technique that allows an effective mapping of alterations in endogenous metabolites levels in biofluids and tissues, we evaluated early signs of renal toxicity from extra urine samples collected in a rat model of intoxication with aristolochic acids. Results: Changes in urine composition were consistent with a proximal tubular damage, most likely initiated by a mitochondrial default and an inappropriate response to oxidative stress. The same metabonomic approach was applied to surplus of urine samples collected from Belgian and Croatian patients in clinical and epidemiological studies, respectively. It allowed a clear discrimination of the Belgian patients from a database of healthy volunteers. On the other hand, a trend to discrimination was noticed when comparing urine samples collected from individuals living in Croatian endemic regions as compared to Croatian non endemic villages. Finally, when included in the same analysis, both Belgian and Croatian patients displayed similar urine metabolic signatures, suggesting a common etiology of both diseases. © 2012 Duquesne M, et al.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Hypoxia and Hypoxia-Inducible Factor Signaling in Muscular Dystrophies: Cause and Consequences

Muscular dystrophies (MDs) are a group of inherited degenerative muscle disorders characterized by a progressive skeletal muscle wasting. Respiratory impairments and subsequent hypoxemia are encountered in a significant subgroup of patients in almost all MD forms. In response to hypoxic stress, compensatory mechanisms are activated especially through Hypoxia-Inducible Factor 1 α (HIF-1α). In healthy muscle, hypoxia and HIF-1α activation are known to affect oxidative stress balance and metabolism. Recent evidence has also highlighted HIF-1α as a regulator of myogenesis and satellite cell function. However, the impact of HIF-1α pathway modifications in MDs remains to be investigated. Multifactorial pathological mechanisms could lead to HIF-1α activation in patient skeletal muscles. In addition to the genetic defect per se, respiratory failure or blood vessel alterations could modify hypoxia response pathways. Here, we will discuss the current knowledge about the hypoxia response pathway alterations in MDs and address whether such changes could influence MD pathophysiology

Cell-free DNA-based prenatal screening via rolling circle amplification: Identifying and resolving analytic issues

Objective: A rolling circle amplification (RCA) based commercial methodology using cell-free (cf)DNA to screen for common trisomies became available in 2018. Relevant publications documented high detection but with a higher than expected 1% false positive rate. Preliminary evidence suggested assay variability was an issue. A multi-center collaboration was created to explore this further and examine whether subsequent manufacturer changes were effective. Methods: Three academic (four devices) and two commercial (two devices) laboratories provided run date, chromosome 21, 18, and 13 run-specific standard deviations, number of samples run, and reagent lot identifications. Temporal trends and between-site/device consistency were explored. Proportions of run standard deviations exceeding pre-specified caps of 0.4%, 0.4% and 0.6% were computed. Results: Overall, 661 RCA runs between April 2019 and July 30, 2022 tested 39,756 samples. In the first 24, subsequent 9, and final 7 months, proportions of capped chromosome 21 runs dropped from 39% to 22% to 6.0%; for chromosome 18, rates were 76%, 36%, and 4.0%. Few chromosome 13 runs were capped using the original 0.60%, but capping at 0.50%, rates were 28%, 16%, and 7.6%. Final rates occurred after reformulated reagents and imaging software modifications were fully implemented across all devices. Revised detection and false positive rates are estimated at 98.4% and 0.3%, respectively. After repeat testing, failure rates may be as low as 0.3%. Conclusion: Current RCA-based screening performance estimates are equivalent to those reported for other methods, but with a lower test failure rate after repeat testing.SCOPUS: ar.jinfo:eu-repo/semantics/publishe