Agomelatine in an Animal Model of PTSD

October 1, 2014 · Posted in Neurobiology, Potential Treatments · Comment 

rat

At the 2014 meeting of the International College of Neuropsychopharmacology, researcher Joseph Zohar presented a poster on the effects of early post-stressor intervention with the drug agomelatine in animals who showed behavioral and molecular responses to stress that served as a model of post-traumatic stress disorder (PTSD).

Agomelatine is available clinically as an antidepressant in Canada and Europe (but not in the US), and can also reduce anxiety and re-synchronize circadian rhythms. Agomelatine is a melatonin (MT1/MT2) receptor agonist and a serotonin 5HT2C antagonist (increasing dopamine and norepinephrine in the frontal cortex).

Long-term behavioral, molecular and structural effects of the drug were assessed in animals. Adult male Sprague-Dawley rats were exposed to the scent of a predator for 10 minutes, and one hour later they were treated acutely for this stress with agomelatine (50mg/kg i.p.) or placebo.

Agomelatine decreased the prevalence of extreme, PTSD-like behavioral and molecular responses to the stressor, such as freezing in place and increased corticosterone. Agomelatine also normalized decreases in brain-derived neurotrophic factor (BDNF) observed in the dentate gyrus of the hippocampus, the cortex (layer III), and the basolateral amygdala. In line with this, agomelatine-treated stressed animals displayed significantly increased number and length of dendrites at glutamate synapses in the hippocampus (including the dentate gyrus and CA1) and reversed the hippocampal neuronal retraction observed in the rats who were given the placebo.

Agomelatine also affected the expression of clock genes in the rats, which regulate biorhythms. These genes lead to the production of the major clock gene proteins Per1 and Per2. Agomelatine normalized Per1 increases in three parts of the brain: the CA3, another glutamate synapse near the dentate gyrus; the suprachiasmatic nucleus over the optic chiasm, important for circadian rhythms; and the basolateral amygdala. Per2, a protein that also drives circadian rhythms, increased in the CA1 synapse of the hippocampus, the suprachiasmatic nucleus and the basolateral amygdala of the stressed rats.

The researchers concluded that the data provide “initial evidence that a single dose of agomelatine administered in the acute aftermath of stress promotes recovery while promoting enhanced neuronal and synaptic plasticity and connectivity in the secondary prevention of PTSD in this model.”

Acute Steroid Injection May Ward Off PTSD

September 10, 2014 · Posted in Potential Treatments · Comment 

woman after a trauma

Low cortisol after a trauma is a risk factor for developing chronic post-traumatic stress disorder (PTSD). Researcher Joseph Zohar studied has been researching the effects of steroids on the development of PTSD and presented some findings at the 2014 meeting of the International College of Neuropsychopharmacology.

Twenty-five patients who experienced a traumatic event and showed acute stress symptoms were given either a single high-dose injection of hydrocortisone (100–140 mg) or a placebo within six hours of the trauma. Follow-up evaluation took place after two weeks, one month, and three months. Those who received this single high dose of hydrocortisone had lowered stress symptoms and less subsequent PTSD compared to those who received placebo.

A Re-Kindling Process Produces Late-Onset PTSD

July 7, 2014 · Posted in Risk Factors · Comment 

post traumatic stress disorder

Not everyone who experiences trauma develops post-traumatic stress disorder (PTSD) immediately. Researchers are discovering that some people go on to develop symptoms like flashbacks or intrusive thoughts, anxiety, and withdrawal, sometimes after long periods of being asymptomatic. Two studies provide hints about the mechanism of this late-onset (or delayed-type) PTSD.

In an article by Danny Horesh et al. published in the journal Psychiatry Research in 2013, a reported 16.5% of 675 Israeli veterans of the 1982 conflict with Lebanon developed late-onset PTSD after a completely non-symptomatic period. The number of deployments soldiers were sent on and the number of terror incidents they experienced within Israel after the war were correlates of the late-onset PTSD, while continuous post-war employment was a protective factor reducing late-onset PTSD.

In a study of 260 older adults (above age 60) who survived the destruction around Galveston Bay, Texas by Hurricane Ike in 2008, Robert H. Pietrzak et al. reported in the Journal of Psychiatry Research in 2013 that 5.3% developed late-onset PTSD. In this case as well, a greater number of subsequent traumatic and stressful life events (and in particular financial difficulties) was associated with late onset of PTSD. The majority of participants in Pietrzak’s study (78.7 %) had no to few PTSD symptoms, while 16.0% had chronic PTSD symptoms from the outset persisting through assessments at three months and 15 months.

Editor’s Note: These two studies reveal that upon prospective follow-up, a small but substantial group of patients (5–16%) develop a late-onset type of PTSD. Acute onset PTSD has been closely linked to new trauma in adulthood, especially following the occurrence of previous (childhood) traumas. The late-occurring variety of PTSD seems to appear after an incubation period, and appears to be closely associated with the occurrence of new traumatic events during the well interval. These new events may result in a kindling-like effect, where repetition of subthreshold stimuli come to evoke a full-blown episode. PTSD appearing after repeated traumatic experiences may operate in a similar fashion to seizures that gradually emerge following repeated electrical stimulation of the amygdala (i.e. amygdala kindling). Read more

Ketamine for Chronic PTSD

July 2, 2014 · Posted in Current Treatments · Comment 

setting up a ketamine drip

We reported in BNN Volume 17, Issue 6 in 2013 on researchers’ efforts to treat symptoms of post-traumatic stress disorder using the drug ketamine. This research by Adriana Feder et al. has now been published in the journal JAMA Psychiatry.

In the study of 41 patients with post-traumatic stress disorder, patients showed a greater reduction in symptoms 24 hours after receiving intravenous (IV) ketamine than after taking IV midazolam, a benzodiazepine used as an active placebo control because it produces anti-anxiety and sedating effects similar to ketamine’s. The patients ranged in age from 18 to 55 years of age and were free of other medication for two weeks before the study. Ketamine was also associated with reduction in depressive symptoms and with general clinical improvement, and side effects were minimal.

HDAC Inhibitor Facilitates Extinction of Fear Memories in the Reconsolidation Window

February 5, 2014 · Posted in Potential Treatments · Comment 

mouse in its hole

Unwanted recall and re-experiencing of traumatic memories is thought to be a crucial mechanism leading to the onset of post-traumatic stress disorder (PTSD). The inability to diminish (extinguish) those memories contributes to the persistence  of PTSD. A new study suggests that the extinction of fear memories can be enhanced by a drug that acts epigenetically to alter the structure of DNA and subsequent gene expression.

DNA is wound around structures called histones, and chemical changes can affect how loosely or tightly the DNA is wound. Johannes Graff et al. reported in the journal Cell in 2014 that application of a histone deacetylase (HDAC) inhibitor, which keeps acetyl groups on histones, ensuring that DNA is wrapped more loosely and is easier to activate (or transcribe), helps rodents revise both new and old fear memories after they have been actively recalled.

When a memory is actively recalled, the trace of that memory in the brain becomes more amenable to revision over the proceeding five minutes to one hour (a period known as the reconsolidation window). New learning and extinction training (to get rid of the memory) lasts much longer when it takes place during the reconsolidation window than when the same procedures are performed 6 hours later (after the reconsolidation window has closed) or if the procedures are performed in the absence of active recall of the memory (when the reconsolidation window is never opened).

We have previously described the 2013 work of Xue et al. published in the journal Science, which showed that this specific procedure could yield long-lasting extinction of a patient’s craving for cocaine or heroin, and could reduce amygdala activation (as observed via functional magnetic resonance imaging) in response to an experiment that produces conditioned fear (Agren et al. Science, 2013).

Editor’s Note: This new work by Graff et al. adds another twist.  Older long-term memories are more stable and less amenable to new learning than more recent (but still long-term) memories.  The application of an HDAC inhibitor changes this and makes even very old memories amenable to lasting revision. The HDAC inhibitor that Graff et al. used was a specific inhibitor for HDAC type II.  However, the anticonvulsant valproate (Depakote) is a potent although nonspecific HDAC inhibitor, and presumably could have the same facilitating effect as the more selective drug.

EMDR (Eye Movement Desensitization and Reprocessing), which has been widely used for the treatment of PTSD, includes active memory recall, immediately followed by an attempt to re-interpret and construct new memories of the trauma.  These elements could open the reconsolidation window. However, EMDR works less well with older memories compared to more recent traumatic memories.

The Graff et al. data would suggest that adding an HDAC inhibitor such as valproate to EMDR-like work might make it more effective in revising more remote memories. Graff et al. encourage controlled clinical trials with a type II inhibitor to confirm that their findings in rodents would generalize to humans. While awaiting such validation through controlled clinical trials, it would not be surprising if clinicians started trying out the paradigm on their own using valproate.

Transgenerational Transmission of PTSD

January 2, 2014 · Posted in Risk Factors, Theory · Comment 

mother with newborn

At a recent scientific meeting, Rachael Yehada showed that PTSD-like traits could be passed transgenerationally. Mothers in New York City who were pregnant on September 11, 2001 and developed post-traumatic stress disorder (PTSD) produced children with low cortisol in their blood (a sign of PTSD). If the fathers had PTSD during the mother’s pregnancy, the children had high cortisol.

These gender-related findings have some parallels in studies of rodents. When a rat pup is separated from its mother for 15 minutes, the mother is overjoyed to see the pup return and licks and grooms it excessively. This maternal overprotection yields an animal with lifelong low cortisol through an epigenetic process. The glucocorticoid receptor gives a feedback message to suppress cortisol, and glucocorticoid receptors are increased in the pups’ brains because of lower methylation of the DNA promoter for glucocorticoid receptors.

If a father has PTSD, there is more methylation of the promoter for glucocorticoid receptors and less expression of them in the forebrain. There is also less feedback suppression of cortisol and the baby exhibits high cortisol.

The methylation of the glucocorticoid receptors in the offspring’s white blood cells is highly correlated (r=0.57, p<0.005, n=23) with methylation in the parent’s white blood cells.

IV Ketamine Superior to IV Midazolam in Adults with PTSD

December 2, 2013 · Posted in Current Treatments · Comment 

patient receiving ketamine

In a recent study, ketamine performed better than an active comparator on several measures in adults with post-traumatic stress disorder (PTSD). Since ketamine has noticeable dissociative effects, researchers have looked for another drug with mind-altering effects that would be a more appropriate comparator than placebo.

At the 2013 meeting of the American Academy of Child and Adolescent Psychiatry, Adriana Feder of Mount Sinai Hospital reported on the randomized study in those with PTSD, in which intravenous ketamine was compared to intravenous midazolam, a potent benzodiazepine that produces anti-anxiety and sedating effects. Murrough et al. previously showed that intravenous ketamine was superior to midazolam in treatment-resistant depression.

In the randomized study Feder described, the participants had suffered PTSD from a physical or sexual assault and had been ill for 12 to 14 years. Those who received ketamine improved more, in some instances for as long as two weeks (ketamine’s blood levels disappear after a few hours, and its clinical antidepressant effects usually last only a few days). Reports of side effects included three patients with blood pressure increases requiring treatment with propranolol, and four patients who each had a transient episode of vomiting.

These controlled data parallel previous open observations. When ketamine was used as a surgical anesthetic during operations on burn patients, only 26.9% subsequently reported PTSD compared to 46.4% who developed PTSD when an alternative to ketamine was used as the anesthetic.

Childhood Adversity and Epigenetic Pockmarks

August 19, 2013 · Posted in Risk Factors · Comment 

Neglected lonely childMaltreatment in childhood may have a lasting impact on health through epigenetics. Epigenetics refers to the idea that events and substances in the environment can affect the structure of DNA by adding chemicals (often methyl or acetyl groups) onto DNA and histones (structures around which DNA is wound) in such a way that the DNA is more or less likely to be transcribed and activated to produce new proteins. Thus our DNA is shaped not only by the genetic inheritance we receive from our parents, but also by events in the environment (which do not alter the sequence of DNA but can influence how easily the DNA gets turned on to produce proteins in our bodies.)

A 2013 study by Divya Mehta et al. published in the Proceedings of the National Academy of Sciences analyzed the childhood backgrounds of adult patients with PTSD and found that patients’ profiles of disease-related gene expression and DNA methylation in blood differed greatly depending on whether or not they had experienced abuse in childhood. Adults who had been abused as children were about twice as likely to show patterns of DNA methylation accompanying their PTSD-related changes in gene expression.

The implication of this research is that childhood trauma can leave a kind of epigenetic pockmark on a person’s DNA, affecting the way the DNA produces proteins, potentially for the rest of that person’s life.

N-acetylcysteine Improves Blast-Induced Mild Traumatic Brain Injury

August 16, 2013 · Posted in Potential Treatments · Comment 

soldier in blast

Michael E. Hoffer et al. reported in the journal PLosOne in 2013 that veterans with blast-induced mild traumatic brain injury had a better acute outcome when they were given the antioxidant N-acetylcysteine (NAC) within the first 24 hours after the trauma versus when they were given placebo during the same period. Forty-two percent of those receiving placebo had a good acute outcome, while 86% of those receiving N-acetylcysteine had a good acute outcome. Memory loss, sleep disturbance, dizziness, and headaches all improved more in the N-acetylcysteine group. NAC’s benefits diminished when it was given 3 or 7 days after the trauma.

Editor’s Note: These data add to the growing list of neuropsychiatric syndromes in which NAC has shown efficacy. These include schizophrenia, bipolar depression, unipolar depression, cocaine and heroin addiction, gambling addiction, trichotillomania (compulsive hair-pulling), obsessive-compulsive disorder (as an adjunctive treatment to SSRIs), and improvement in irritability and stereotypy (repetitive behaviors) in children with autism.

Given what appears so far to be a relatively benign side effects profile for NAC, and the potential for severe consequences from traumatic brain injury (TBI), a case for wider use of NAC (for example in emergency rooms) might be made.

The mechanisms of action of NAC in different syndromes remains to be clarified. Researcher Michael Berk used NAC in schizophrenia and bipolar disorder and more recently in unipolar depression because it has antioxidant properties. Peter Kalivas found that NAC can normalize glutamate in the reward area of the brain through actions on the cystine-glutamate exchanger, and it also increases clearance of glutamate by increasing the glutamate transporter in glial cells. NAC decreases the amount of cued glutamate release in a part of the brain called the nucleus accumbens, which may be helpful in recovery from pathological habits. NAC also has anti-inflammatory and perhaps neuroprotective effects, and it increases brain-derived neurotrophic factor (BDNF), which protects neurons and is important for long-term learning and memory. Which of these many actions is important in the treatment of PTSD is not yet known.

One Doctor’s Protocol for the Treatment of Severe PTSD

July 8, 2013 · Posted in Comorbidities, Potential Treatments · Comment 

PTSDNote: The following article discusses “off-label” treatments for the treatment of PTSD or traumatic brain injury, i.e. those which are not FDA-approved for these purposes. In some of these instances, there is no controlled research to support the use of these drugs in patients with PTSD. Thus the ideas noted here cannot be taken as anything more than anecdotal information from personal experience. Patients and physicians must make their own decisions about any of the strategies reported in this or other issues of BNN.

At a recent scientific conference, Vaishali P. Bakshi, a renowned Canadian psychopharmacologist, shared a novel treatment strategy he has developed for patients with exceptionally profound degrees of post-traumatic stress disorder (PTSD), which, particularly among military veterans, can be compounded by traumatic brain injury.

Treatment options based on placebo-controlled clinical trials are sometimes insufficient for the treatment of seriously ill patients. FDA-approved treatment for PTSD consists of serotonin-selective antidepressants, while exposure therapies (in which the patient is gradually exposed to more of the stimuli that triggered symptoms) are the recommended psychotherapy, but these methods often leave patients highly disabled.

Bakshi’s typical treatment algorithm goes well beyond these treatment guidelines to find solutions for hard-to-treat patients. He first addresses sleep disturbance, which often occurs in PTSD. He suggests the anticonvulsant levetiracetam (Keppra), starting at doses of 150mg per night and increasing to 500–1000mg as tolerated. This highly sedating anticonvulsant not only improves sleep but may also help cognition, since it is structurally similar to other cognitive enhancers such as piracetam. Levetiracetam also decreases the hippocampal hyperactivity associated with some forms of cognitive dysfunction, as we’ve noted before. In order to further enhance sleep effects, Bakshi adds trazodone at 50­–150mg per night as needed.

Instead of selective serotonin reuptake inhibitors (SSRIs), Bakshi recommends the selective serotonin and norepinephrine reuptake inhibitors (SNRIs). Among these, he prefers desvenlafaxine (Pristiq) over venlafaxine, as desvenlafaxine has fewer interactions with other drugs. Theoretically, duloxetine (Cymbalta) is another SNRI that could be used.

Another component of Bakshi’s treatment plan is topiramate (Topamax), which can target many comorbidities of PTSD, including alcohol and substance abuse, particularly stimulant abuse. In addition, topiramate has efficacy in anger attacks, which often accompany PTSD.

In patients with ongoing problems with depression and/or cognition, Bakshi adds bupropion (Wellbutrin). Read more

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