Study reveals why some depressed patients have blood inflammation

May 5, 2016, King's College London
Study reveals why some depressed patients have blood inflammation

A new King's College London study reveals why some - but not all - people have depression that appears to be caused by blood inflammation.

These insights could help researchers to develop novel treatment strategies for the many depressed who do not get better using current antidepressants.

Recent research suggests that patients with depression have measurable changes in the blood that indicate activation of the inflammatory system - a biological response which is predominantly directed to fight infection but which also has an important role in regulating mood and behaviour.

Blood is known to worsen in the brain, which occurs when the body both overproduces and then struggles to remove molecules called 'free radicals.' These free radicals break down brain connections and disrupt the brain's chemical signalling, which in turn can lead to the development of by reducing the brain's protective mechanisms.

This new King's research, published in Neuropsychopharmacology, indicates that some depressed patients are predisposed to develop depression when their inflammatory system is activated because they are more 'biologically sensitive' to inflammation. As a result, their brains are more likely to suffer.

Researchers have known for many years that approximately one third of patients who take an anti-viral immune drug called 'interferon-alpha' develop depression, because this drug activates the inflammatory system. The King's College London research team set out to study patients taking interferon-alpha as a model for inflammation-induced depression, in order to dissect the mechanisms through which an activated inflammatory system causes depressive symptoms in some but not all individuals.

They measured the activation of multiple biological systems in the blood of 58 patients before and after the inflammatory activation with interferon-alpha, and correlated changes in these systems with the onset of depressive symptoms.

The researchers found that patients who developed depressive symptoms following the inflammatory activation tended to be more biologically sensitive to interferon-alpha. Specifically, they had a more reactive inflammatory system, and also showed more changes in biological systems involved in oxidative stress and in the protection of brain cells.

Dr Nilay Hepgul, lead author of the study from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London, said: 'Our results are important not only for understanding the high prevalence of depression amongst individuals receiving interferon-alpha treatment, but also to identify those at risk of developing in the context of high inflammation due to other causes, such as severe stress or medical illnesses.'

Professor Carmine Pariante, senior author of the study from the IoPPN at King's College London, said: 'Both oxidative stress and brain protective mechanisms can be considered future targets for the development of novel, effective antidepressant strategies, especially for patients with high levels of inflammation who do not get better using current antidepressants.'

Professor Pariante added: 'Our next aim is to understand the implications of this increased inflammation in the blood and whether it has direct consequences for the brain, using neuroimaging techniques.

'We also need to understand why some patients are more biologically sensitive to increased inflammation. Do they have a specific genetic profile that makes them more susceptible, or has exposure to stress life events had an impact - or both?'

Explore further: Inflammation attacks brain's reward center

More information: Nilay Hepgul et al. Transcriptomics in Interferon-α-Treated Patients Identifies Inflammation-, Neuroplasticity- and Oxidative Stress-Related Signatures as Predictors and Correlates of Depression, Neuropsychopharmacology (2016). DOI: 10.1038/npp.2016.50

Related Stories

Inflammation attacks brain's reward center

February 2, 2016
A new study by Neil Harrison and colleagues published in Biological Psychiatry suggests that a brain reward center, the striatum, may be directly affected by inflammation and that striatal change is related to the emergence ...

Omega-3 fatty acids may prevent some forms of depression

October 1, 2014
Patients with increased inflammation, including those receiving cytokines for medical treatment, have a greatly increased risk of depression. For example, a 6-month treatment course of interferon-alpha therapy for chronic ...

Uncovering the source of inflammatory malaise

October 22, 2012
(Medical Xpress)—A study conducted by researchers at Emory indicates that inflammation targets a part of the brain called the basal ganglia, causing symptoms of depression and fatigue. The study was recently reported in ...

Inflammation markers could guide depression treatments

January 12, 2016
Psychiatrists investigating depression have been energized in recent years by reports of rapid, successful treatment with drugs that interfere with the brain chemical glutamate, such as the anesthetic ketamine.

Inflammatory pathways could be key to resolving heart disease and depression link

March 24, 2016
Heart health scientists are working to establish therapies to combat the physical link between cardiovascular disease and depression.

New biological evidence reveals link between brain inflammation and major depression

January 28, 2015
A new study by the Centre for Addiction and Mental Health (CAMH) found that the measure of brain inflammation in people who were experiencing clinical depression was increased by 30 per cent. The findings, published today ...

Recommended for you

People with family history of alcoholism release more dopamine in expectation of alcohol

May 23, 2018
People with a family history of alcohol use disorder (AUD) release more dopamine in the brain's main reward center in response to the expectation of alcohol than people diagnosed with the disorder, or healthy people without ...

Why we fail to understand our smartphone use

May 23, 2018
Checking your phone dozens of times a day indicates unconscious behaviour, which is "extremely repetitive" say psychologists.

Study confirms that men and women tend to adopt different navigation strategies

May 23, 2018
When navigating in a known environment, men prefer to take shortcuts to reach their destination more quickly, while women tend to use routes they know. This is according to Alexander Boone of UC Santa Barbara in the US who ...

Early life trauma in men associated with reduced levels of sperm microRNAs

May 22, 2018
Exposure to early life trauma can lead to poor physical and mental health in some individuals, which can be passed on to their children. Studies in mice show that at least some of the effects of stress can be transmitted ...

Training compassion 'muscle' may boost brain's resilience to others' suffering

May 22, 2018
It can be distressing to witness the pain of family, friends or even strangers going through a hard time. But what if, just like strengthening a muscle or learning a new hobby, we could train ourselves to be more compassionate ...

Study finds popular 'growth mindset' educational interventions aren't very effective

May 22, 2018
A new study co-authored by researchers at Michigan State University and Case Western Reserve University found that "growth mindset interventions," or programs that teach students they can improve their intelligence with effort—and ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.