Clinical validation of EDIT-B test for the diagnosis of bipolar disorder

Introduction

Bipolar disorder (BD) is a psychiatric disorder characterized by alternating episodes of high mood and low mood similar to depression. To differentiate BD patients from unipolar (UN) depressed patients remains a challenge and the clinical scales available failed to distinguish these 2 populations. ALCEDIAG developed EDIT-B, the first blood test able to make a differential diagnosis of BD. Based on RNA editing modifications measurement and AI, the test requires a simple blood draw and equipment available in most central laboratories. A first study on 160 UN and 95 BD patients allowed a differential diagnosis with an AUC of 0.935 and high specificity (Sp=84.6%) and sensitivity (Se=90.9%). A multicentric clinical study has been set up to validate these performances.

Objectives

The objective of this project is to run a multicentric clinical study in Europe and assess the performances of the test.

Methods

The EDIT-B project, led by Alcediag, is supported by EIT-Health grant (European institute of Innovation and Technology) and gathers 4 clinical centers in 3 countries (France, Spain, Danemark), a CRO for the clinical study management (Aixial), a CRO for the development of a diagnostic kit (Veracyte), a diagnostic lab for molecular biology analyses (Synlab), and a regulatory company (PLG).

Results

At the end of the study, the EDIT-B performance will be confirmed and the test will be CE-marked.

Conclusions

This test will address the needs of millions of patients suffering from misdiagnosis and therefore allow them to receive the correct treatment.

Disclosure

JDA, NS and DW are employees of Alcediag.

Game changer in the diagnosis of bipolar disorder using RNA editing-based blood biomarkers

Introduction

In clinical practice, differentiating Bipolar Disorder (BD) from unipolar depression is challenging due to the depressive symptoms, which are the core presentations of both disorders. Patients with BD are often misdiagnosed during depressive episodes resulting in a delay in proper treatment and a poor management of their condition.

Objectives

The aim of the present study is to discriminate between unipolar depression and BD using a panel of RNA edited blood biomarkers.

Methods

Depressed patients were classified according to clinical scores in MADRS and IDSC-30 depression scales. After blood collection and RNA extraction, we used whole-transcriptome sequencing to identify differential A-to-I editing events, and Targeted Next Generation Sequencing to validate those biomarkers.

Results

We discovered 646 variants differentially edited between depressed patients and control in a discovery cohort of 57 participants. After using stringent criteria and biological pathway analysis, 6 biomarker candidates were singled out and tested in a validation cohort of 160 patients suffering from unipolar depression and 95 BD patients in a depressive episode, which allowed a differential diagnosis of BD with an AUC of 0.935 and high specificity (Sp=84.6%) and sensitivity (Se=90.9%).

Conclusions

We have shown that a combination of 6 blood RNA editing-related biomarkers allows to discriminate unipolar and bipolar depression This 6 BMKs panel may be crucial to improve BD diagnosis and orientate the treatment therefore addressing the needs of millions of patients suffering from misdiagnosis and incorrect treatment for their diseases. This will change the game for the management of patients.

Disclosure

No significant relationships.

RNA editing blood biomarkers for predicting mood alterations in HCV patients

Treatment-emergent depression is a common complication in patients with chronic hepatitis C virus (HCV) infection undergoing antiviral combination therapy with IFN-α and ribavirin. It has recently been shown that changes in A-to-I RNA editing rates are associated with various pathologies such as inflammatory disorders, depression and suicide. Interestingly, IFN-α induces gene expression of the RNA editing enzyme ADAR1-1 (ADAR1a-p150) and alters overall RNA editing activity. In this study, we took advantage of the high prevalence of pharmacologically induced depression in patients treated with IFN-α and ribavirin to test the interest of RNA editing–related biomarkers in white blood cells of patients. In this 16-week longitudinal study, a small cohort of patients was clinically evaluated using standard assessment methods prior to and during antiviral therapy and blood samples were collected to analyse RNA editing modifications. A-I RNA editing activity on the phosphodiesterase 8A (PDE8A) gene, a previously identified RNA editing hotspot in the context of lupus erythematosus, was quantified by using an ultra-deep next-generation sequencing approach. We also monitored gene expression levels of the ADAR enzymes and the PDE8A gene during treatment by qPCR. As expected, psychiatric evaluation could track treatment-emergent depression, which occurred in 30% of HCV patients. We show that PDE8A RNA editing is increased in all patients following interferon treatment, but differently in 30% of patients. This effect was mimicked in a cellular model using SHSY-5Y neuroblastoma cells. By combining the data of A-I RNA editing and gene expression, we generated an algorithm that allowed discrimination between the group of patients who developed a treatment-emergent depression and those who did not. The current model of drug-induced depression identified A-I RNA editing biomarkers as useful tools for the identification of individuals at risk of developing depression in an objective, quantifiable biological blood test.

Cerebrospinal Aβ11-x and 17-x levels as indicators of mild cognitive impairment and patients' stratification in Alzheimer's disease

In the present work, the concentrations of Aβ11-x and Aβ17-x peptides (x=40 or 42), which result from the combined cleavages of β-amyloid precursor protein (AβPP) by β'/α or α/γ-secretases, respectively, were assessed in cerebrospinal fluid (CSF) samples from patients with Alzheimer's disease (AD) or mild cognitive impairment (MCI). Specific multiplexed assays were set up using new anti-40 and anti-42 monoclonal antibodies (mAbs) for the capture of these N-truncated Aβ peptides and anti-11 or anti-17 mAbs for their detection. The specificity, sensitivity and reproducibility of such assays were assessed using synthetic peptides and human cell models. Aβ11-x and Aβ17-x were then measured in CSF samples from patients with AD (n=23), MCI (n=23) and controls with normal cognition (n=21). Aβ11-x levels were significantly lower in patients with MCI than in controls. Compared with the combined quantification of Aβ1-42, total Tau (T-Tau) and phosphorylated Tau (P-Tau; AlzBio3, Innogenetics), the association of Aβ11-40, Aβ17-40 and T-Tau improved the discrimination between MCI and controls. Furthermore, when patients with MCI were classified into two subgroups (MCI ≤1.5 or ≥2 based on their CDR-SB (Cognitive Dementia Rating-Sum of Boxes) score), the CSF Aβ17-40/Aβ11-40 ratio was significantly higher in patients with CDR-SB ≤1.5 than in controls, whereas neither Aβ1-42, T-Tau nor P-Tau allowed the detection of this subpopulation. These results need to be confirmed in a larger clinical prospective cohort.