CHILDHOOD OBESITY: Soon a saliva risk assessment test?

 While in rich countries, one in three children is overweight, identifying early indicators of obesity in young children could allow preventive measures to be taken against obesity. However, oral bacteria could hold a key to obesity or rather a signature of future risk, concludes this research presented in Scientific Reports. From this work by the "Penn State", which shows that the composition of the oral microbiota or the micro-organisms residing in the mouth of children aged 2 years can predict their weight gain, emerges the prospect of a simple saliva test making it possible to predict the risk of obesity later in life.

 

Because the trajectories of weight gain during infancy are well linked to the composition of the oral microbiota and the presence of certain bacterial communities, in children aged 2 years, which suggests the possibility of an early indicator of obesity .

 

Exploring the relationship between microbiota and weight gain: this trial, INSIGHT, involves 300 children with the objective of looking at whether and how appropriate parental intervention at the start of life can prevent the development of obesity. The trial is also designed to identify biological and social risk factors for obesity. It identifies a child's oral microbiota as linked to weight gain during the 2 years following birth: the digestive tract is inhabited by a variety of microorganisms, including beneficial bacteria, which contribute to digestion and immunity. This gut microbiotais modified by changes in diet and can vary considerably between individuals. Some variations in the gut microbiota have been associated with obesity in some adults and adolescents, but the relationship with weight gain has never been explored. Finally, the oral microbiota is generally studied in relation to periodontal disease, and periodontal disease has been linked, in some cases, to obesity.

Sarah Craig, a postdoctoral researcher in biology at Penn State and her team explored all possible direct associations between the oral microbiota and weight gain in 226 children. Data analysis finds that:

• the oral microbiota of children who have gained weight rapidly is less diversified with therefore fewer distinct bacterial communities;
• in the oral microbiota of children who gained weight rapidly, the Firmicutes/Bacteroidetes ratio, 2 of the most common groups of bacteria found in the human microbiota, is higher; this ration constitutes a distinctive signature of the risk of obesity;
• weight gain in children is also linked to the diversity of the mother's oral microbiota: this could reflect a genetic predisposition of the mother and child to a similar microbiota, or a similar diet and environment for the mother and the child.

 

 

Good health is also a great diversity of the intestinal microbiota  : “This great diversity helps protect against inflammation or harmful bacteria and is important for the stability of digestion in the face of changes in diet or environment. There is also a certain balance between these 2 bacterial groups, Firmicutes and Bacteroidetes. Disturbances of this balance can lead to dysregulation of digestion”.

 

Obesity is signed earlier in the oral microbiota than in the gut microbiota: Lower diversity and a higher Firmicutes to Bacteroidetes (F/B) ratio in the gut microbiota have already been observed in adults and adolescents suffering from obesity. However, here the researchers did not identify a relationship with weight gain, suggesting that the gut microbiota of the 2-year-old child may not be fully established. The results thus suggest that obesity may be signed earlier in the oral microbiota than in the intestinal microbiota.

 

If these data were confirmed, it would be possible to develop an oral test for detecting the risk of obesity, a very interesting prospect when oral samples are very simple to perform.

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SCHIZOPHRENIA: Polygenic score predicts response to antipsychotics

 The polygenic risk score, already used in the personalized treatment of cancers, finds here a new application, in the prediction of the response to antipsychotic drugs, in patients with schizophrenia. According to this work by a team from the Feinstein Institute for Medical Research (New York) presented in the American Journal of Psychiatry, the future of psychosis treatment also involves precision medicine.

 

Schizophrenia is not a rare psychotic illness, it is one of the main causes of disability in rich countries. Characterized by delusions, hallucinations, and disorganized thoughts and behaviors, schizophrenia is treated with antipsychotic drugs, but it is not uncommon to have to "try" several different treatments before obtaining a satisfactory response from the patient. An uncertainty that weighs heavily not only on patients and their families, but also on professionals and health systems. The objective here is therefore to be able to predict the most appropriate treatment.

 

The interest of polygenic risk scores in psychiatry: here the team uses genetic tests to predict the response to drugs in patients suffering from a first episode of schizophrenia. And rather than looking for a single gene, researchers use the still recent approach of “polygenic risk scores”, based on the search for several thousand genetic variants across the entire genome. These scores will allow, underlines the main author, Dr. Jian-Ping Zhang, professor at the Feinstein Institute, “to better represent and detect the very complex genetic nature of schizophrenia”.

 

Towards precision psychiatry: Researchers show that patients with a high polygenic risk score or higher genetic load are indeed less likely to respond to conventional antipsychotic treatment. These results are further reproduced in 2 independent cohorts. These data open the way to “precision medicine” approaches in psychiatry, as we can know in oncology.

 

In short, this work is described as a major advance in the field of precision medicine for schizophrenia, “a major advance over current trial -and- error approaches  ”.

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BRAIN TUMORS: Still the potential of liquid biopsies

 Liquid biopsies for the detection and monitoring of brain tumors have considerable potential, reaffirm these scientists from the Cancer Research Institute UK who are making progress in the development of liquid biopsies detecting tumor DNA in cerebrospinal fluid (CSF). Their liquid biopsy technique, tested here in 13 patients presenting with a glioma, makes it possible to detect tumor DNA in 5 of these patients. Promising results, presented in the journal EMBO Molecular Medicine.

 

Liquid biopsies are fluid or liquid samples from patients, from blood, urine, saliva, or CSF. These biopsies offer the means to detect or monitor the disease in a less invasive way than tissue biopsies. This less intrusive test finds its natural application for the diagnosis of tumors that are difficult to access, such as brain or lung tumors, where tissue sampling can be complex and risky for patients.

 

Scientists from the Institute of Cancer Research UK (Cambridge) are here analyzing the CSF, the fluid that bathes the brain and spinal cord of 13 patients with glioma and using an inexpensive and widely available technique of whole genome sequencing, they managed to detect tumor DNA in 39% of them. New here is the examination of the size of the mutated DNA fragments, which are shorter than those from healthy cells. This other means of detecting tumor DNA seems to make it possible to increase the detection rate.

 

Liquid biopsy is sometimes more "fine" than conventional biopsy: in one of the patients, the researchers compare the genetic modifications identified via tissue analysis and CSF analysis. While overall these changes appear broadly similar, CSF delivers undetected changes in some tissue samples, suggesting that liquid biopsy by CSF analysis may more accurately reflect the spectrum of genetic alterations associated with brain tumors.

 

Liquid biopsies thus confirm their promises: “even if”, underlines the main author, Dr. tests for brain tumors have lagged due to low levels of tumor DNA present in body fluids, especially blood. . However, this small study shows that an inexpensive and available technique can be used to analyze tumor DNA in cerebrospinal fluid. The idea is therefore to use this technique more widely to identify patients likely to benefit from other tests likely to contribute to the monitoring of their disease and to be able to opt for more personalized treatments.  

 

Professor Charles Swanton, Chief Clinician at Cancer Research UK, concludes: “  Brain tumor survival remains low and there is an urgent need for further research to identify strategies to better manage these complex diseases . ” This study lays an important foundation for developing liquid biopsies.

The researchers will continue with a larger number of patients and refine the approach so as to be able to adapt it in clinical practice, whether in the diagnosis or the monitoring of the response to treatment in the management of brain tumours.

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