Eduardo CesarThe fact that there are no laboratory tests that can diagnose psychiatric disorders can sometimes lead to delays in detecting an illness, thus compromising patient treatment. Traditionally, diagnoses are obtained through psychiatric evaluation, in which a physician recognizes the signs and symptoms reported by the patient and classifies them as depression, schizophrenia, bipolar disorder or some other adverse mental condition. The success of this subjective and error-prone strategy depends largely on the clinical experience of the psychiatrist, the ability of the patients to recognize and articulate the symptoms, and even reports from family members. Now, a group of Brazilian scientists has made progress in its attempt to devise a laboratory test that uses a patient’s blood to assist in the diagnosis of schizophrenia and bipolar disorder, psychiatric diseases that together affect 81 million people all over the world, according to the World Health Organization (WHO). As of now, health authorities such as the Brazilian Health Surveillance Agency (ANVISA) and its U.S. counterpart Food and Drug Administration (FDA) have approved no other tests that can identify these diseases.
The study was headed up by chemist Ljubica Tasic, a professor at the Chemistry Institute of the University of Campinas (IQ-Unicamp), working with researchers from the Federal University of São Paulo (Unifesp), and it has resulted in the filing of a patent with the National Institute of Industrial Property (INPI). The methodology is based on analysis of the set of metabolites (compounds created by enzymatic activity during metabolism) contained in the liquid portion of blood – the serum–which consists of more than 2,000 metabolites, including lipids, amino acids, proteins, acids and aromatic compounds.
“An innovative feature of the study was its use of metabolomics, a recent platform that is now being applied to various fields of medicine. Instead of searching for some specific biomarkers associated with psychiatric disorders, we analyzed a wide array of metabolites found in the blood and developed the patient’s metabolomic profile,” says Unifesp professor Elisa Brietzke, a psychiatrist specialized in metabolic changes caused by mental illnesses and one of the creators of the methodology. “We investigated this because we find it unlikely that just one or a small group of substances in the blood is able to reliably identify the presence of complex mental disorders such as schizophrenia and bipolar disorder.”
Combined technique
The study included 150 volunteers, one-third of them healthy (the control group), one-third with schizophrenia and one-third with bipolar disorder–in other words, the researchers started with a well-defined and characterized sample population. That helps enable researchers to describe the metabolomic profile of the volunteers and associate it with each of the three groups. The psychiatric assessment of the volunteers was conducted by the Unifesp team, led by Brietzke. Blood samples were then collected and prepared for analysis by the group led by Mirian Akemi Hayashi, a professor in the Pharmacology Department of Unifesp, which then sent them to Unicamp. In order to analyze the volunteers’ blood and develop the metabolomic profile, the Campinas team used the technique known as hydrogen-1 nuclear magnetic resonance (1H NMR) along with chemometrics, which is an approach that uses mathematical and statistical methods to improve the understanding of chemical information.
In the 1H NMR technique, after applying a radiofrequency to the blood sample in the presence of a strong and homogeneous magnetic field, the hydrogen atoms of molecules present in the serum emit signals from which a spectrum can be acquired. “That spectrum contains signals from the hydrogen atoms of all the molecules present in the blood serum whose concentration allows for detection,” Tasic explains. The next step was to use chemometrics to determine which metabolite was responsible for the chemical shift that enabled separation of the analyzed groups–the researchers focused on those that presented greater alteration in the profile of patients with schizophrenia or bipolar disorder as compared to healthy patients. That stage of the work included the participation of chemist Ronei Jesus Poppi, a professor at IQ-Unicamp. Finally, they determined which principal metabolites were altered and identified to which group (healthy, schizophrenic or those with bipolar disorder) the tested blood sample belonged.
“We successfully completed the development of this first phase of the project once the planned analyses were finalized,” says Tasic. “We can therefore state that among the three groups of individuals studied differences were detected among various amino acids, aromatic compounds, D-glucose, acids, creatine, and aliphatic chains of lipids. There are some metabolites that were detected in patients with schizophrenia and others that were only found in patients with bipolar disorder.”
Despite the good results obtained, the researchers caution that the test is not yet ready for use. “Our plan is for our studies to lead to the development of a diagnostic kit. The target metabolites for schizophrenia and bipolar disorder will still have to be validated and quantified by other techniques.” For this reason, Tasic plans to propose chemical or biochemical methods for the qualitative and quantitative analysis that can then be used in an easy screening test. She estimates that another 5 to 10 years of research and improvement, along with private funding, will be needed before the test can be marketed. The Unicamp Agency for Innovation (Inova) is already working on licensing the technology.
For psychiatrist Luis Augusto Paim Rohde, a professor in the Department of Psychiatry and Legal Medicine at the Federal University of Rio Grande do Sul (UFRGS), initiatives such as that by the group of researchers from Unicamp and Unifesp are welcome and should be encouraged. “The search for biological markers for psychiatric patients is extremely important,” he says. “But we need to keep the research in perspective. This is a study involving small samples, divided among patients with severe cases and a control group with typical development. We need assistance in the differential diagnosis of cases with complex symptoms that are often part of different tests.” According to Rohde, the only Brazilian to take part in the most recent Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) in the U.S., “we’re moving in the right direction, but the results are only preliminary.”
Project
Metabolomic profiling of severe mental disorders using Nuclear Magnetic Resonance (NMR) (nº 2014/18938-8); Grant Mechanism Regular Research Project; Principal Investigator Ljubica Tasic (IQ-Unicamp); Investment R$134,263.02 and US$79,664.23.
