Behavior results from the complex interplay between genes and environment. Our genes predispose us to how we act and feel, by influencing how our brain develops and functions. This way, certain genetic variants in our genome increase the risk of developing mental health problems (while others may decrease this risk). Whether someone actually develops a mental health disorder or not, depends on many other factors in our environment, such as stressors and experiences. Nonetheless, studying these genetic risk factors for mental health conditions is an important aspect of understanding these disorders.

As an example of such research, we have now identified several genetic risk factors that contribute to cocaine dependence. For this we combined genetic data from a lot of studies, including more than 6000 individuals. What’s even more interesting is that we found that the genetic variants that are related to cocaine dependence are correlated with the genetic risk factors for other conditions such as ADHD, schizophrenia and major depression. What this means is that certain small variations in DNA increase the risk for not just cocaine dependence, but actually several psychiatric conditions. Probably, there is a common biological mechanism that underlies all these conditions. Thanks to our genetic research, we are now only a small step closer towards unraveling these mechanisms.

We also wrote a blog post explaining our research findings. You can read it here: https://mind-the-gap.live/2019/07/04/cocaine-dependence-is-in-part-genetic-and-it-shares-genetic-risk-factors-with-other-psychiatric-conditions-and-personality-traits/

The original publication can be found here: https://www.sciencedirect.com/science/article/pii/S0278584619301101?via%3Dihub

Please share and like us:

Our body is colonized by trillions of microorganisms that are important for vital processes. Gut microbiota are the microorganisms living in the intestinal gut and play an essential role in digestion, vitamin synthesis and metabolism, among others. The mouth and the large intestine contain the vast majority of gut microbiota whether the stomach only contains few thousands of microorganisms, especially due to the acidity of its fluids. Microbiota composition is constantly changing, affecting the well-being and health of the individual.

Each individual has a unique microbiota composition, and it depends on several factors including diet, diseases, medication and also the genetics of the individual (host) (Figure). Some medicines, especially antibiotics, reduce bacterial diversity. Strong and broad spectrum antibiotics can have longer effects on gut microbiota, some of them up to several years. Genetic variation of an individual also affects the microbiota composition, and the abundance of certain microorganisms is partly genetically determined by the host.

The main contributor to gut microbiota diversity is diet, accounting for 57% of variation. Several studies have demonstrated that diet’s composition has a direct impact on gut microbiota. For example, an study performed on mice showed that “Western diet” (high-fat and sugar diet), alters the composition of microbiota in just one day! On the other hand, vegetarian and calorie restricted diet can also have an effect on gut microbiota composition.

Prebiotics and probiotics are diet strategies more used to control and reestablish the gut microbiota and improve the individual’s health. Probiotics are non-pathogenic microorganisms used as food ingredients (e.g. lactobacillus present in yoghurt) and prebiotics are indigestible food material (e.g. fibers in raw garlic, asparagus and onions), which are nutrients to increase the growth of beneficial microorganisms.

In the last years the new term psychobiotics has been introduced to define live bacteria with beneficial effects on mental health. Psychobiotics are of particular interest for improving the symptomatology of psychiatric disorders and recent preclinical trials have show promising results, particularly in stress, anxiety and depression.

Overall, these approaches are appealing because they can be introduced in food and drink and therefore provide a relatively non-invasive method of manipulating the microbiota.

AUTHORS:
Judit Cabana-Domínguez and Noèlia Fernàndez-Castillo

Please share and like us:

Increasing evidence is showing that the gut microbiota can alter the brain and behavior, and thus may play a role in the development of psychiatric and neurodevelopmental disorders, such as autism and schizophrenia.

Animal models are a useful tool to study this mechanism. For example, germ-free (GF) mice, which have never been exposed to microorganisms, are compared with mice exposed to microorganisms, known as conventional colonized mice (CC). Recent studies have schizophrenia and autismreported that GF animals show increased response to stress, as well as reduced anxiety and memory. In most cases, these alterations are restricted to males, in which there are higher incidence rates of neurodevelopmental disorders compared with females.

Mice, like humans, are a social species and are used to study social behavior. A recent study compared GF and CC mice using different sociability tests. GF mice showed impairments in social behavior compared with CC mice, particularly in males. Interestingly, they demonstrate that social deficits can be reversed by bacterial colonization of  the GF gut (GFC), achieving normal social behavior.

Microbiota seem to be crucial for social behaviors, including social motivation and preference for social novelty. Microbiota also regulate repetitive behaviors, characteristic of several disorders such as autism and schizophrenia.

Bacterial colonization can change brain function and behavior, suggesting that microbial-based interventions in later life could improve social impairments and be a useful tool to effect the symptoms of these disorders.

This blog was co-authored by Noèlia Fernàndez and Judit Cabana

Please share and like us:

We know that high-energy food (rich in refined sugars and fats) is addictive and can lead to an eating addiction and obesity. Addiction is a very severe disorder with chronic and relapsing components. People who suffer from addiction show compulsivity, persistence to seek the reward (food), and high motivation to overconsume in some cases.

Food Addictions in People and MiceTo study eating addiction, we have developed a mouse model that shows persistence to eat, high motivation for palatable food and resistance to punishment in obtaining the food. We have tested these three characteristics in several genetically identical animals and selected two extreme groups: Mice that are vulnerable to eating addiction and mice that are resilient to it.

Mice have more than 25,000 genes in their genome, and they can be turned on or turned off (‘expressed’ or ‘not expressed’) depending on certain needs or circumstances.

We are now investigating the activation status of a certain type of genes, the ones encoding the so-called microRNAs that are very important as they are involved in regulating the function of other genes. An alteration in the status of one of these genes can have numerous downstream consequences.

In particular, our studies highlighted several microRNA genes that are involved in multiple brain functions, like synaptic plasticity (variation in the strength of nerve signaling) or neuronal development. Now we will test these alterations in patients to try to find convergent abnormalities.

All this work is being done at the Department of Genetics, Microbiology & Statistics (Universitat de Barcelona) and at the Neuropharmacology lab at the Universitat Pompeu Fabra, both based in Catalonia.

Co-authored by Bru Cormand, Judit Cabana, Noelia Fernàndez

Please share and like us:

The human gut is colonized by microorganisms in a similar number as the cells of the human body.

“Microbiota” refers to these microorganisms, and it maintains a symbiotic relationship with the host, contributing to essential functions such as food digestion, energy harvest and storage, the function of the intestinal barrier, and the immune system and protection against pathogenic organisms. Prenatal and postnatal factors can alter the composition of the microbiota, such as stress and diet or the use of antibiotics (see image).

Prenatal and Postnatal factors influence gut-brain axis and mental healthFor instance, stress during pregnancy can alter the composition of vaginal microbiota, which affects the composition of the microbiota of the newborn and is related to gastrointestinal (GI) symptoms and allergic reactions. Interestingly, there is a bidirectional communication between the GI tract and the central nervous system (the gut-brain axis) that involves neuronal and metabolic pathways, immune and endocrine mechanisms. Changes in the composition of the microbiota can lead to altered development of the brain and increased risk of psychiatric and neurodevelopmental disorders, such as anxiety, depression and autism (see image).

Depression is one of the most recurrent stress-related disorders that highly impacts the quality of life. Fecal samples of patients with depression have a decreased microbial richness and diversity than controls. The use of probiotics have been shown to help with sad mood and negative thoughts, which may be a potential preventive strategy for depression.

Autism is characterized by impaired communication, poor social engagement and repetitive behaviours, with frequent GI symptoms. We know that the bacteria composition is more diverse in autistic individuals than in unaffected subjects.

For other psychiatric disorders, such as Attention deficit/hyperactivity disorder (ADHD) and Schizophrenia, there is indirect evidence for a role of the microbiota, but more studies are needed.

This connection between the gut and brain is two way communication, and is known as “The Gut-Brain Axis.”

Our knowledge of the impact of gut microbiota on brain function is growing fast, which may pave the way to possible applications for the treatment of psychiatric and neurodevelopmental disorders.

Authors Judit Cabana, Bru Cormand, and Noelia Fernandez Castillo are in the Department of Genetics, Microbiology & Statistics, University of Barcelona, Catalonia, Spain

More information can be found in: Felice VD, O’Mahony SM. The microbiome and disorders of the central nervous system. (2017) Pharmacol Biochem Behav. Sep;160:1-13.
https://www.ncbi.nlm.nih.gov/pubmed/28666895

Please share and like us:


Welcome to New Brain Nutrition. You can enjoy FREE Online Courses when you Log In or Join here.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 728018

New Brain Nutrition is a project and brand of Eat2BeNice, a consortium of 18 European University Hospitals throughout the continent.

Partners:
You may log in here to our Intranet website with your authorized user name and password.