Nutrient dynamics of 12 Sphagnum species during establishment on a rewetted bog.

Peatland degradation through drainage and peat extraction have detrimental environmental and societal consequences. Rewetting is an option to restore lost ecosystem functions, such as carbon storage, biodiversity and nutrient sequestration. Peat mosses (Sphagnum) are the most important peat-forming species in bogs. Most Sphagnum species occur in nutrient-poor habitats; however, high growth rates have been reported in artificial nutrient-rich conditions with optimal water supply. Here, we demonstrate the differences in nutrient dynamics of 12 Sphagnum species during their establishment in a 1-year field experiment at a Sphagnum paludiculture area in Germany. The 12 species are categorized into three groups (slower-, medium- and fast-growing). Establishment of peat mosses is facilitated by constant supply of nutrient-rich, low pH, and low alkalinity surface water. Our study shows that slower-growing species (S. papillosum, S. magellancium, S. fuscum, S. rubellum, S. austinii; often forming hummocks) displayed signs of nutrient imbalance. These species accumulated higher amounts of N, P, K and Ca in their capitula, and had an elevated stem N:K quotient (>3). Additionally, this group sequestered less C and K per m2 than the fast and medium-growing species (S. denticulatum, S. fallax, S. riparium, S. fimbriatum, S. squarrosum, S. palustre, S. centrale). Lower lawn thickness may have amplified negative effects of flooding in the slower-growing species. We conclude that nutrient dynamics and carbon/nutrient sequestration rates are species-specific. For bog restoration, generating ecosystem services or choosing suitable donor material for Sphagnum paludiculture, it is crucial to consider their compatibility with prevailing environmental conditions.

EPIC: an evaluation of the psychological impact of early-phase clinical trials in cancer patients.

BACKGROUND: Anxiety and depression in patients with cancer is associated with decreased quality of life and increased morbidity and mortality. However, these are often overlooked and untreated. Early-phase clinical trials (EPCTs) recruit patients with advanced cancers who frequently lack future treatment options, which may lead to increased anxiety and depression. Despite this, EPCTs do not routinely consider psychological screening for patients. PATIENTS AND METHODS: This prospective observational study explored levels of anxiety and depression alongside impact of trial participation in the context of EPCTs. The Hospital Anxiety and Depression Scale and the Brief Illness Perceptions Questionnaire were completed at the point of EPCT consent, the end of screening and at pre-specified time points thereafter. RESULTS: Sixty-four patients (median age 56 years; median Eastern Cooperative Oncology Group performance status 1) were recruited. At consent, 57 patients returned questionnaires; 39% reported clinically relevant levels of anxiety whilst 18% reported clinically relevant levels of depression. Sixty-three percent of patients experiencing psychological distress had never previously reported this. Males were more likely to be depressed (P = 0.037) and females were more likely to be anxious (P = 0.011). Changes in anxiety or depression were observed after trial enrolment on an individual level, but not significant on a population level. CONCLUSIONS: Patients on EPCTs are at an increased risk of anxiety and depression but may not seek relevant support. Sites offering EPCTs should consider including psychological screening to encourage a more holistic approach to cancer care and consider the sex of individuals when tailoring psychological support to meet specific needs.

Association and epistatic analysis of white matter related genes across the continuum schizophrenia and autism spectrum disorders: The joint effect of NRG1-ErbB genes.

BACKGROUND: Schizophrenia-spectrum disorders (SSD) and Autism spectrum disorders (ASD) are neurodevelopmental disorders that share clinical, cognitive, and genetic characteristics, as well as particular white matter (WM) abnormalities. In this study, we aimed to investigate the role of a set of oligodendrocyte/myelin-related (OMR) genes and their epistatic effect on the risk for SSD and ASD. METHODS: We examined 108 SNPs in a set of 22 OMR genes in 1749 subjects divided into three independent samples (187 SSD trios, 915 SSD cases/control, and 91 ASD trios). Genetic association and gene-gene interaction analyses were conducted with PLINK and MB-MDR, and permutation procedures were implemented in both. RESULTS: Some OMR genes showed an association trend with SSD, while after correction, the ones that remained significantly associated were MBP, ERBB3, and AKT1. Significant gene-gene interactions were found between (i) NRG1*MBP (perm p-value = 0.002) in the SSD trios sample, (ii) ERBB3*AKT1 (perm p-value = 0.001) in the SSD case-control sample, and (iii) ERBB3*QKI (perm p-value = 0.0006) in the ASD trios sample. DISCUSSION: Our results suggest the implication of OMR genes in the risk for both SSD and ASD and highlight the role of NRG1 and ERBB genes. These findings are in line with the previous evidence and may suggest pathophysiological mechanisms related to NRG1/ERBBs signalling in these disorders.

MiR-205-driven downregulation of cholesterol biosynthesis through SQLE-inhibition identifies therapeutic vulnerability in aggressive prostate cancer.

Prostate cancer (PCa) shows strong dependence on the androgen receptor (AR) pathway. Here, we show that squalene epoxidase (SQLE), an enzyme of the cholesterol biosynthesis pathway, is overexpressed in advanced PCa and its expression correlates with poor survival. SQLE expression is controlled by micro-RNA 205 (miR-205), which is significantly downregulated in advanced PCa. Restoration of miR-205 expression or competitive inhibition of SQLE led to inhibition of de novo cholesterol biosynthesis. Furthermore, SQLE was essential for proliferation of AR-positive PCa cell lines, including abiraterone or enzalutamide resistant derivatives, and blocked transactivation of the AR pathway. Inhibition of SQLE with the FDA approved antifungal drug terbinafine also efficiently blocked orthotopic tumour growth in mice. Finally, terbinafine reduced levels of prostate specific antigen (PSA) in three out of four late-stage PCa patients. These results highlight SQLE as a therapeutic target for the treatment of advanced PCa.

Genomic context of NTRK1/2/3 fusion-positive tumours from a large real-world population.

Neurotrophic tropomyosin receptor kinase (NTRK) gene fusions are rare oncogenic drivers in solid tumours. This study aimed to interrogate a large real-world database of comprehensive genomic profiling data to describe the genomic landscape and prevalence of NTRK gene fusions. NTRK fusion-positive tumours were identified from the FoundationCORE® database of >295,000 cancer patients. We investigated the prevalence and concomitant genomic landscape of NTRK fusions, predicted patient ancestry and compared the FoundationCORE cohort with entrectinib clinical trial cohorts (ALKA-372-001 [EudraCT 2012-000148-88]; STARTRK-1 [NCT02097810]; STARTRK-2 [NCT02568267]). Overall NTRK fusion-positive tumour prevalence was 0.30% among 45 cancers with 88 unique fusion partner pairs, of which 66% were previously unreported. Across all cases, prevalence was 0.28% and 1.34% in patients aged ≥18 and <18 years, respectively; prevalence was highest in patients <5 years (2.28%). The highest prevalence of NTRK fusions was observed in salivary gland tumours (2.62%). Presence of NTRK gene fusions did not correlate with other clinically actionable biomarkers; there was no co-occurrence with known oncogenic drivers in breast, or colorectal cancer (CRC). However, in CRC, NTRK fusion-positivity was associated with spontaneous microsatellite instability (MSI); in this MSI CRC subset, mutual exclusivity with BRAF mutations was observed. NTRK fusion-positive tumour types had similar frequencies in FoundationCORE and entrectinib clinical trials. NTRK gene fusion prevalence varied greatly by age, cancer type and histology. Interrogating large datasets drives better understanding of the characteristics of very rare molecular subgroups of cancer and allows identification of genomic patterns and previously unreported fusion partners not evident in smaller datasets.

[Validation of a French version of the 16-item Prodromal Questionnaire (fPQ16) in adolescents and young adults seeking help]. / Validation d'une version française du 16-items Prodromal Questionnaire (fPQ16) chez des adolescents et jeunes adultes consultant en psychiatrie.

INTRODUCTION: The duration of untreated psychosis has been largely associated with poor outcomes in psychosis. Actual diagnostic tools may be used by very specialized teams and need sustained evaluation. We present a French version of a self-report questionnaire: the 16-item Prodromal Questionnaire (fPQ16). Our objective was to evaluate its predictive value for an ultra-high-risk state (UHR) or psychosis. The population enrolled was consulting in a young adults and adolescents center in Sainte-Anne hospital, Paris, France. METHODS: PQ16 had first been translated into French and independently back translated and validated by the original authors. Between November 2016 and May 2018, every C'JAAD consulting patient was proposed to fill in the fPQ16. Each patient was next evaluated with the French version of the comprehensive assessment of at-risk mental state (CAARMS), which detects UHR or psychosis. Statistical analysis of fPQ16 concurrent validity was performed using ROC curves. fPQ16 acceptability was studied by four additional questions especially designed for that purpose. RESULTS: One hundred participants were included. Mean age was 19.85years (SD 3.3 y). Fifty-eight percent of patients included were diagnosed with UHR (40%) or psychotic (18%) state after CAARMS evaluation. Mean score at fPQ16 was 5.7 (SD 3.8). Best cut-off score was 4 positive items, with excellent sensibility (91%) and correct specificity (60%). Positive predictive value of fPQ16 was 76%. Area under the curve was 0.85 (P<0.0001). fPQ16 showed good acceptability. DISCUSSION: fPQ16 had good screening performances in our population. Cut-off score was lower than in previous studies, but performances were equal or better. As a well-accepted and short questionnaire, the fPQ16 could be a great screening tool in primary care. A version with 18-items, including two items focused on thought content and disorganization that are missing in PQ16, is under evaluation.

Intrapatient comparisons of efficacy in a single-arm trial of entrectinib in tumour-agnostic indications.

BACKGROUND: Entrectinib is a tropomyosin receptor kinase inhibitor approved for the treatment of neurotrophic tyrosine receptor kinase (NTRK) fusion-positive solid tumours based on single-arm trials. Traditional randomised clinical trials in rare cancers are not feasible; we conducted an intrapatient analysis to evaluate the clinical benefit of entrectinib versus prior standard-of-care systemic therapies. METHODS: Patients with locally advanced/metastatic NTRK fusion-positive tumours enrolled in the global phase II, single-arm STARTRK-2 trial were grouped according to prior systemic therapy and response. The key analysis used growth modulation index [GMI; ratio of progression-free survival (PFS) on entrectinib to time to discontinuation (TTD) on the most recent prior therapy]; ratio ≥1.3 indicated clinically meaningful efficacy. Additional analyses investigated TTD and objective response rate (ORR) for entrectinib and prior therapies. RESULTS: Seventy-one patients were included; 51 received prior systemic therapy. In 38 patients who progressed on prior therapy, ORR was 60.5% (23/38) with entrectinib and 15.8% (6/38) with the most recent prior therapy. Median PFS [11.2 months; 95% confidence interval (CI) 6.7-not estimable] for entrectinib exceeded median TTD (2.9 months; 95% CI 2.0-4.9) for most recent prior therapy. From the intrapatient analysis of GMI, 65.8% had a ratio ≥1.3 and median GMI was 2.53. Consistent results were observed at more stringent GMI thresholds; 60.5% of patients had GMI ≥1.5 or ≥1.8 and 57.9% had GMI ≥2.0. CONCLUSIONS: ORR was high and PFS was longer on entrectinib versus TTD on prior therapy. Furthermore, 65.8% of patients experienced clinically meaningful benefit based on GMI. This intrapatient analysis demonstrates comparative effectiveness of entrectinib in a rare, heterogeneous adult population.

Innervation and vascular supply of the first dorsal interosseous muscle and palmar interosseous muscle of the index: An anatomic descriptive study.

INTRODUCTION: The first dorsal interosseous muscle (FDI) and palmar interosseous muscle of the index (P2I) are essential for the strength and mobility of the index finger. This study aims to describe the course of the deep branch of the ulnar nerve (DBUN) and the blood supply to these muscles. MATERIAL AND METHODS: An anatomical cadaver study was carried out with 14 upper limbs from fresh, non-embalmed cadavers. All limbs were filled with an equal amount, based on weight, of colored silicone and diluent that was combined and catalyzed with 5% curing agent. The location of the DBUN's termination was specified relative the carpometacarpal joint. Every artery supplying either muscle was identified and documented. RESULTS: The DBUN had a slightly convex path, distal to the hook of the hamate and penetrated the FDI muscle at an average 41% of the second metacarpal length. An average of 1.3 branches to the P2I and 2.6 branches to the FDI were found. Four artery pedicles coming from the deep palmar arch supply the FDI with an average of one consistent and exclusive pedicle to the FDI and three pedicles heading to the P2I. According to the classification of Mathes and Nahai, the FDI has a type 2 blood supply and the P2I has a type 3 blood supply. CONCLUSION: In-depth knowledge of the vascular network supplying the FDI and P2I muscles and the course of the DBUN is essential when the DBUN is damaged or when dissecting these muscles for index pollicization.

The paradox-breaking panRAF plus SRC family kinase inhibitor, CCT3833, is effective in mutant KRAS-driven cancers.

BACKGROUND: KRAS is mutated in ∼90% of pancreatic ductal adenocarcinomas, ∼35% of colorectal cancers and ∼20% of non-small-cell lung cancers. There has been recent progress in targeting G12CKRAS specifically, but therapeutic options for other mutant forms of KRAS are limited, largely because the complexity of downstream signaling and feedback mechanisms mean that targeting individual pathway components is ineffective. DESIGN: The protein kinases RAF and SRC are validated therapeutic targets in KRAS-mutant pancreatic ductal adenocarcinomas, colorectal cancers and non-small-cell lung cancers and we show that both must be inhibited to block growth of these cancers. We describe CCT3833, a new drug that inhibits both RAF and SRC, which may be effective in KRAS-mutant cancers. RESULTS: We show that CCT3833 inhibits RAF and SRC in KRAS-mutant tumors in vitro and in vivo, and that it inhibits tumor growth at well-tolerated doses in mice. CCT3833 has been evaluated in a phase I clinical trial (NCT02437227) and we report here that it significantly prolongs progression-free survival of a patient with a G12VKRAS spindle cell sarcoma who did not respond to a multikinase inhibitor and therefore had limited treatment options. CONCLUSIONS: New drug CCT3833 elicits significant preclinical therapeutic efficacy in KRAS-mutant colorectal, lung and pancreatic tumor xenografts, demonstrating a treatment option for several areas of unmet clinical need. Based on these preclinical data and the phase I clinical unconfirmed response in a patient with KRAS-mutant spindle cell sarcoma, CCT3833 requires further evaluation in patients with other KRAS-mutant cancers.

Micro- and macrovascular function in patients suffering from primary adrenal insufficiency: a cross-sectional case-control study.

BACKGROUND: Despite adequate glucocorticoid (GC) and mineralocorticoid (MC) replacement therapy, patients suffering from primary adrenal insufficiency (AI) have an increased mortality, mainly due to cardiovascular diseases. Only little knowledge exists on the contribution of MC substitution to the cardiovascular risk. Therefore, this study investigates the impact of plasma renin concentration on parameters of micro- and macrovascular function. METHODS: 26 patients with primary AI [female = 18, age: 51 (28; 78) years; BMI: 24 (18; 40) kg/m2; disease duration: 18 (5; 36) years] were included in this cross-sectional analysis. Intima media thickness (IMT) and pulse wave velocity (PWV) were investigated to assess macrovascular remodeling and arterial stiffness. Microvascular function was estimated by post-occlusive reactive hyperemia using laser Doppler fluxmetry. Baseline perfusion, biological zero, peak perfusion, time to peak and recovery time were recorded. Patients were grouped according to their median plasma renin concentration of previous visits (Reninhigh vs Reninlow) and were compared to a group of healthy women [age: 44 (43; 46) years; BMI: 24.2 (21.8; 27.5)]. RESULTS: PWV was significantly higher in AI patients compared to controls [9.9 (5; 18.5) vs 7.3 (6.8; 7.7) m/s; p < .01], whereas no differences in microvascular function could be found. In Reninlow time to peak perfusion was significantly longer [6.0 (3; 15) vs 3.5 (1.5; 11) s; p < .05], whereas no differences in IMT and PWV were observed between Reninhigh and Reninlow. No impact of GC dose was observed. CONCLUSIONS: Microvascular function is not impaired in patients with primary AI under adequate replacement therapy, although higher renin concentrations are associated with subclinical improvements. No relation between RAAS activity and macrovascular function is observed, while arterial stiffness might be increased in primary AI.

[Management of cardiovascular co-morbidities in young patients with early onset psychosis: State of the art and therapeutic perspectives]. / Prise en charge des comorbidités cardio-vasculaires chez les jeunes patients souffrant d'une psychose débutante : état des lieux et perspectives thérapeutiques.

Patients with psychiatric disorders have a decrease in their life expectancy. Excess mortality of patients with schizophrenia was demonstrated by a meta-analysis in the late 1990s and has not decreased for the past 30years. A recent meta-analysis including nearly 250,000 patients with schizophrenia found an average decrease in life expectancy of 14.5years (CI95: 11,2-17,8), more important for men than for women: 15.9 (CI95: 13,8-18,0) vs 13.6 (CI95: 11,4-15,8). A closer look at the somatic comorbidities, including metabolic syndrome, and investigation of causes of death of these patients highlighted already well-known factors, namely late diagnosis and insufficient treatment of physical diseases, side effects of antipsychotics, unhealthy lifestyle (poor diet, smoking, excessive alcohol consumption and lack of exercise), and higher risk of suicide and accident. Concerning ultra-high risk (UHR) patients, a 2016 meta-analysis of 47 studies evaluated the cardiovascular risk factors. They reported a higher prevalence of smoking in UHR (odds ratio 2,3) and a lower level of physical activity associated with a normal BMI (Body Mass Index) compared to the control population. A meta-analysis about patients with a first episode of psychosis (FEP) found reduced total and LDL cholesterol levels and an increased triglyceride level compared to the control population. One study found alteration of the fasting plasmatic levels of glucose and insulin, as well as insulin resistance in FEP patients, compared to controls albeit the HbA1c level was not significantly different. A meta-analysis reported a prevalence of metabolic syndrome of 10 % in FEP or drug naïve patients versus 35 % and 20 % in treated and untreated patients with chronic schizophrenia respectively. Somatic comorbidities usually appear during the first two years of the disease. Some interventions have proven their efficacy in reducing the occurrence of metabolic syndrome and other cardiovascular risk factors. For instance, metformin, a treatment for type 2 diabetes that is allowed from the age of 10, has shown benefits in children and adolescents receiving second-generation antipsychotics in a recent meta-analysis, with a mean weight loss of 3.23kg (IC95 % -5.59 -0.86) after 16 weeks. Dietary-hygienic interventions are also effective in reducing cardiovascular risk. Other interventions such as omega-3 supplementation, vitamin D, N-acetylcysteine, and fasting have not proven to be effective. Comprehensive care programs have been developed to promote somatic care in psychiatric patients, such as the Canadian HeAL (Healthy Active Lives) program. These programs are more effective when proposed from the beginning of the disease and the introduction of antipsychotics. In this review, because there is no French recommendation, we translate a tool for the prescription of metformin and the Canadian recommendations from the HeAL program. Generalization of these programs to all young psychotic patients could improve their life expectancy and reduce the overall mortality. Prevention of cardiovascular risk factors and cardio-metabolic monitoring of treatments must be part of the standard of care in early psychosis. These programs aim at providing patients with the quality of somatic and mental care they are entitled to. This requires the involvement of all stakeholders, including patients and their families but also psychiatrists and other caregivers.

Pedicled flap from the first dorsal branch of the proper palmar digital artery of the fingers: An anatomy study.

The pedicled flap from the first dorsal branch of the proper palmar digital artery (FBPPDA) of the fingers is an option for reconstructing digital skin defects. It has the advantage of being innervated by the dorsal branch of the proper palmar digital nerve (DBPPDN) associated with the artery. However, no studies on the anatomical variations of the neurovascular pedicle have been performed yet. The objective of our study was to evaluate the anatomical variations in the neurovascular pedicle, determine its relationships with other anatomical structures, describe the dissection technique for the FBPPDA and explore potential indications. We conducted an anatomical study with eight upper limbs from fresh adult cadavers. Twenty-six fingers (6 index, 6 middle, 8 ring, 8 little) were dissected after intra-arterial silicone injection. We found a pedicle composed of the FBPPDA and the DBPPDN in all fingers. The artery arises an average 19mm from the bifurcation of the common palmar digital artery. The DBPPDN's configuration relative to the FBPPDA varied; in the main variant - found in 58% of cases - the nerve was superficial and proximal position to the artery. After its origin, the pedicle ran on the superficial aspect of the extensor hood along an oblique path from proximal to distal and from palmar to dorsal. Its path ended with its penetration into the skin paddle of the flap just upstream the proximal interphalangeal (PIP) joint. The skin paddle corresponded to the functional skin unit represented by the dorsal surface of the middle phalanx and that of the PIP joint. Its average length was 33mm (26-40) and its average width was 21mm (15-30). The arc of rotation was sufficient to reach homodigital and heterodigital cutaneous defects. Based on our findings, this flap is a reliable and reproducible option for finger skin defects. The size of its paddle and its innervation make it an interesting alternative to conventional flaps.

[Health professionals facing the coronavirus disease 2019 (COVID-19) pandemic: What are the mental health risks?] / Les professionnels de santé face à la pandémie de la maladie à coronavirus (COVID-19) : quels risques pour leur santé mentale ?

OBJECTIVES: The coronavirus disease 2019 (COVID-19) pandemic has caused major sanitary crisis worldwide. Half of the world has been placed in quarantine. In France, this large-scale health crisis urgently triggered the restructuring and reorganization of health service delivery to support emergency services, medical intensive care units and continuing care units. Health professionals mobilized all their resources to provide emergency aid in a general climate of uncertainty. Concerns about the mental health, psychological adjustment, and recovery of health care workers treating and caring for patients with COVID-19 are now arising. The goal of the present article is to provide up-to-date information on potential mental health risks associated with exposure of health professionals to the COVID-19 pandemic. METHODS: Authors performed a narrative review identifying relevant results in the scientific and medical literature considering previous epidemics of 2003 (SARS-CoV-1) and 2009 (H1N1) with the more recent data about the COVID-19 pandemic. We highlighted most relevant data concerning the disease characteristics, the organizational factors and personal factors that may contribute to developing psychological distress and other mental health symptoms. RESULTS: The disease characteristics of the current COVID-19 pandemic provoked a generalized climate of wariness and uncertainty, particularly among health professionals, due to a range of causes such as the rapid spread of COVID-19, the severity of symptoms it can cause in a segment of infected individuals, the lack of knowledge of the disease, and deaths among health professionals. Stress may also be caused by organizational factors, such as depletion of personal protection equipment, concerns about not being able to provide competent care if deployed to new area, concerns about rapidly changing information, lack of access to up-to-date information and communication, lack of specific drugs, the shortage of ventilators and intensive care unit beds necessary to care for the surge of critically ill patients, and significant change in their daily social and family life. Further risk factors have been identified, including feelings of being inadequately supported, concerns about health of self, fear of taking home infection to family members or others, and not having rapid access to testing through occupational health if needed, being isolated, feelings of uncertainty and social stigmatization, overwhelming workload, or insecure attachment. Additionally, we discussed positive social and organizational factors that contribute to enhance resilience in the face of the pandemic. There is a consensus in all the relevant literature that health care professionals are at an increased risk of high levels of stress, anxiety, depression, burnout, addiction and post-traumatic stress disorder, which could have long-term psychological implications. CONCLUSIONS: In the long run, this tragic health crisis should significantly enhance our understanding of the mental health risk factors among the health care professionals facing the COVID-19 pandemic. Reporting information such as this is essential to plan future prevention strategies. Protecting health care professionals is indeed an important component of public health measures to address large-scale health crisis. Thus, interventions to promote mental well-being in health care professionals exposed to COVID-19 need to be immediately implemented, and to strengthen prevention and response strategies by training health care professionals on mental help and crisis management.

[Neurodevelopment and cannabis]. / Cannabis et neurodéveloppement.

Brain development is a complex phenomenon, stretching from fetal life to adolescence, during which brain maturation proceeds through a series of ordered events including critical periods of plasticity. The brain is particularly sensitive to the environment during these changes. The endocannabinoid system participates directly and indirectly in these plasticity and maturation processes. The main psychoactive component of cannabis, the delta-9-tetrahydrocanabinol, can cross the placental barrier, is present in breastmilk and diffuses in the brain. It interacts with the endocannabinoid signaling, especially through the activation of cannabinoid receptors 1 CB1R, which can lead to abnormal neurodevelopmental processes and neuronal circuits functions. Therefore, exposure to cannabis in utero, in perinatal phase, as well as during the adolescence disrupts the brain maturation and can cause disturbances on the cognitive, psychotic and addictive levels that persist far beyond the period of exposure. Several factors modulate the risk of such complications, but studies performed in animal models as well as in human cohorts have shown that exposure during both the critical perinatal and adolescence phases is a risk factor per se. Current knowledge encourages the dissemination of objective information to young people, to prevent and limit early exposure and its consequences.

[Membrane lipids in schizophrenia and early phases of psychosis: Potential biomarkers and therapeutic targets?] / Lipides membranaires dans la schizophrénie et la psychose débutante : de potentiels biomarqueurs et pistes thérapeutiques ?

The various roles of membrane lipids in human health has urged researchers to study their impact in neuropsychiatric diseases, especially in schizophrenia spectrum disorders and more recently in early stages of psychosis. The progress in mass spectrometry technologies now allows a more comprehensive analysis of phospholipids (PL) and their fatty acid (FA) molecular species. FA are defined by a carbon chain of variable length and are said to be unsaturated when their chain has one or more carbon-carbon double bonds. The PL are composed of a hydrophilic polar head with a phosphoric acid group and an hydrophobic part with FAs; they encompass glycerophospholipids and sphingolipids. The plasma membrane is a complex and dynamic structure consisting of a lipid bilayer composed of an outer layer and an inner layer of specific lipid composition. The permanent remodeling of membrane lipids involves phospholipases especially the phospholipase A2. Seventy percent of the brain consists of lipids from different classes and molecular species. Most of the brain lipids are composed of polyunsaturated fatty acid (PUFA)-enriched diacyl classes where omega-3 and omega-6 molecular species predominate. The balance between omega-3 and omega-6 is important for the neurodevelopment. PUFA are also involved in neurogenesis and neurotransmission. Sphingomyelin (SM) is a sphingolipid that influences inflammation, cell proliferation and lipid rafts formation. It is an important component of myelin sheaths of white matter and therefore is involved in cerebral connectivity. In rat models, deficiency in omega-3 causes abnormalities in dopaminergic neurotransmission, impacts on the functioning of some receptors (including cannabinoids CB1, glutamatergic N-methyl-D-aspartate receptor, NMDA), and increases sensitivity to hallucinogens. In contrast, omega-3 supplementation improves cognitive function and prevents psychotic-like behavior in some animal models for schizophrenia. It also reduces oxidative stress and prevents demyelination. The historical membrane hypothesis of schizophrenia has led to explore the lipids abnormality in this disorder. This hypothesis was initially based on the observation of an abnormal membrane prostaglandin production in schizophrenia caused by a membrane arachidonic acid deficiency. It has evolved emphasizing the various PUFA membrane's roles in particular regarding oxidative stress, inflammation and regulation of the NMDA receptors. In patients with mental disorders, low omega-3 index is more frequent than in the general population. This lipid abnormality could lead to myelination abnormalities and cognitive deficits observed in patients. It could also participate in oxidative stress abnormalities and inflammation reported in schizophrenia. On the other hand, low omega-3 index deficit was reported to be associated with an increased cardiovascular risk, and omega-3 supplementation may also have a positive cardiovascular impact in psychiatric patients, even more than in the general population. The presence of membrane lipid abnormalities is also found in patients during the first psychotic episode (FEP). The omega-3 supplementation improved the recovery rate and prevented the loss of gray matter in FEP. In patients at ultra-high risk to develop a psychotic disorder (UHR), omega-3 supplementation has been associated with a reduction of the rate of conversion to psychosis and with metabolic changes, such as decreased activity of phospholipase A2. However, this study has not as yet been replicated. Not all patients exhibit lipid abnormalities. Several studies, including studies from our team, have found a bimodal distribution of lipids in patients with schizophrenia. But some studies have found differences (in PUFA) in the acute phase whereas our studies (on phospholipids) are in chronic phases. It will be interesting to study in more depth the links between these two parameters. Furthermore, we identified a subgroup which was identified with a deficit in sphingomyelin and PUFA whereas others have found an increase of sphingomyelin. Individuals with this abnormal lipid cluster had more cognitive impairments and more severe clinical symptoms. Because the niacin test is an indirect reflection of arachidonic acid levels, it has been proposed to identify a subset of patients with membrane lipids anomalies. Niacin test response is influenced by several factors related to lipid metabolism, including cannabis use and phospholipase A2 activity. Despite progress, the function and impact of membrane lipids are still poorly understood in schizophrenia. They could serve as biomarkers for identifying biological subgroups among patients with schizophrenia. In UHR patients, their predictive value on the conversion to psychosis should be tested. Omega-3 supplementation could be a promising treatment thanks to its good tolerance and acceptability. It could be more appropriate for patients with PUFA anomalies in a more personalized medical approach.