New Drug for PTSD? 

Did you know that patients with post-traumatic stress disorder (PTSD) often struggle to forget  traumatic memories, even long after the danger has passed? This failure to extinguish fear  memories has long puzzled scientists and posed a major hurdle for treatment, especially since  current medications targeting serotonin receptors offer limited relief for only a subset of  patients. 

In a new discovery, scientists at the Institute for Basic Science (IBS) and Ewha Womans  University have uncovered a new brain mechanism driving PTSD and a promising drug that may  counteract its effects. Led by Dr. C. Justin LEE at the IBS Center for Cognition and Sociality and  Professor LYOO In Kyoon at Ewha Womans University, the team has shown that excessive GABA  (gamma-aminobutyric acid) produced by astrocytes, which are star-shaped support cells in the  brain, impairs the brain’s ability to extinguish fear memories. This deficit is a core feature of  PTSD and helps explain why traumatic memories can persist long after the threat has passed. 

Crucially, the researchers found that a brain-permeable drug called KDS2010, which selectively  blocks the monoamine oxidase B enzyme responsible for this abnormal GABA production, can  reverse PTSD-like symptoms in mice. The drug has already passed Phase 1 safety trials in  humans, making it a strong candidate for future PTSD treatments. 

PTSD remains difficult to treat, with current medications targeting serotonin pathways  providing limited relief for many patients. The new study focused on the medial prefrontal  cortex (mPFC), a region of the brain critical for regulating fear, and found that PTSD patients  had unusually high levels of GABA and reduced cerebral blood flow in this area. These findings  emerged from brain imaging studies of more than 380 participants. GABA levels decreased in  patients who showed clinical improvement, pointing to the chemical’s central role in recovery. 

To uncover the origin of this excess GABA, the researchers examined postmortem human brain  tissue and used PTSD-like mouse models. They discovered that astrocytes, not neurons, were  producing abnormal amounts of GABA via the enzyme monoamine oxidase B (MAOB). This  astrocyte-derived GABA impaired neural activity, blocking the brain’s ability to forget traumatic  memories. 

Excessive GABA produced by astrocytes in the medial prefrontal cortex (mPFC) is a key factor in  Post-Traumatic Stress Disorder (PTSD), leading to the inability to forget traumatic memories.  This astrocytic GABA (gamma-aminobutyric acid) impairs neural activity, which can be targeted  by monoamine oxidase B (MAOB) inhibitors, such as the drug KDS2010. Research has shown  that blocking MAOB normalizes astrocytic GABA levels, restores blood flow in the mPFC, and 

improves fear extinction in PTSD mouse models, with KDS2010 currently in Phase 2 clinical trials  for PTSD.  

Excessive astrocytic GABA disrupts the brain’s ability to extinguish fear memories, a core  feature of PTSD. This dysregulation is observed in the medial prefrontal cortex (mPFC), a brain  region crucial for fear regulation. High levels of astrocyte-derived GABA inhibit neuronal activity  and reduce cerebral blood flow (CBF) in the mPFC. Studies found that elevated prefrontal GABA  levels in PTSD patients were associated with symptom severity and improved with clinical  recovery. 

The research identified astrocytic monoamine oxidase B (MAOB) as the enzyme responsible for  producing excessive GABA in the mPFC of individuals with PTSD. Targeting astrocytic MAOB  offers a new therapeutic path for PTSD. A selective, reversible MAOB inhibitor called KDS2010  has been shown to normalize astrocytic GABA, restore mPFC blood flow, and improve fear  extinction in PTSD mouse models. KDS2010 is a strong candidate for clinical trials in PTSD.  

The drug has successfully completed Phase 1 trials and is currently in Phase 2 clinical trials to  evaluate its effectiveness in treating PTSD. This research provides a novel therapeutic strategy  for PTSD by directly targeting the underlying astrocytic GABA mechanism. 

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