Neuroimmunological Model of Traumatic Memory

The recruitment status of this study is unknown because the information has not been verified recently.
Verified November 2006 by Ziv Hospital.
Recruitment status was  Recruiting
Sponsor:
Information provided by:
Ziv Hospital
ClinicalTrials.gov Identifier:
NCT00396695
First received: November 6, 2006
Last updated: NA
Last verified: November 2006
History: No changes posted
  Purpose

Traumatic events may lead to strong emotional episodic memories common in Post- Traumatic Stress Disorder(PTSD). Intense affect may inhibit efficacy of glutamatergic neurotransmission in two particular areas of the limbic system that have been implicated in the processing of emotionally charged memories: the amygdala and the hippocampus(1,2).

Dysfunction of glutamatergic neurotransmission is associated with disbalance of long-term potentiation (LTP) and long-term depression (LTD)- two underlying mechanisms that cooperate to achieve synaptic plasticity and its expressations- learning and memory(3). LTP- the long lasting enhancement of synaptic function includes changes in the amount of neurotransmitter glutamate released into a synapse, changes in the levels of key proteins in synapses, protein phosphorylation and changes the density of receptors on their synaptic membranes. LTD is the inverse of LTP, a long lasting reduction in synaptic transmission (4). Interactions among the different forms of plasticity underlie different forms of memories. Normally these mechanisms are balanced.

In the current literature there is data that a class I major histocompatibility complex (MHC class I) molecules, known to be important for immune responses to antigen, are expressed also by neurons that undergo activity-dependence, long-term structural and synaptic modifications (5). The brain produces its own immune molecules, the proteins MHC class I and CD3-zeta (a component of receptors for MHC class I). In the immune system, the two proteins act as part of a lock and key system to recognize and get rid of the body’s foreign invaders. The CD3-zeta polypeptide is component of the T cell antigen receptor (TCR) which contribute to its efficient cell surface expression and account for part of its transducing capability (6).

In the brain, they may be part of a signaling system that recognizes and eliminates inappropriate neural connections. Expression of MHC class I is regulated by the naturally occurring electrical activity, and sensitive to both natural and pathological changes in the activity. Electrical activity of neurons drives to an establishment of the final pattern of connection. Changes in the strength of individual synapses such as potention and depression leads to stabilization and withdrawal, respectively, of the affected connections. There are data, that in mice with deficiency of MHC class I and CD3-zeta the LTP in the hippocampus is enhanced significantly and LTD is absent. Thus, MHC class I is crucial for translating activity into changes in synaptic strength and neuronal connectivity in vivo. He required for normal activity dependent potentiation, depression, removal of inappropriate connection and responding to injury in the CNS (6).

Glutamate receptors play critical roles in LTP/LTD mechanisms. Some researchers consider that a key role in pathogenesis of PTSD is being played by excessive excitation of NMDA-receptors in limbic system structures (1). The existing data allows to assume, that equation of plasticity mechanisms depends on mutual relations between the MHC class I and glutamate receptors.

T-cells, like neurons, express high levels of glutamate receptors that are identical to the brain glutamate receptors. Presence of ionotropic and metabotropic glutamate receptors in membranes of lymphocytes makes them sensitive to the same alarm molecules which operate neuronal activity. Glutamate by itself triggers several T-cell activation which differs quantitatively or qualitatively from that ones triggered by “classical’ T-cell activators like antigens(7). There are data about influence of T cell receptor-CD3 complex- on the expression of T-cells glutamate receptors (8). It is possible, that the key roles in this function play CD3-zeta.


Condition Intervention
Stress Disorders, Post-Traumatic
Procedure: Blood test

Study Type: Observational
Study Design: Observational Model: Defined Population
Primary Purpose: Screening
Time Perspective: Cross-Sectional
Official Title: Neuroimmunological Model of Traumatic Memory

Resource links provided by NLM:


Further study details as provided by Ziv Hospital:

Estimated Enrollment: 40
Study Start Date: October 2006
Estimated Study Completion Date: December 2007
Detailed Description:

Working hypothesis and aims

Trauma-related LTP/LTD disbalance in favor of potentaion and excessive excitation of glutamate receptors generated when arousing experiences occur in conjunction with memory-related activation of the hippocampus and amigdala. Traumatic memories connected to the amplification of mechanism LTP, when new information is unable to induce reliable LTD, which reverses synaptic plasticity formed during previous emotional learning experiences.

MHC class I and CD3-zeta play a key role in these changes. We assume that the composition of glutamate receptors and CD3-zeta expression in T-cells can be used as the model reflecting for LTP/LTD balance in CNS.

The work includes the learning of following parameters:

  1. The Expression in T-cells: glutamate receptors, CD3-zeta.
  2. Glutamate level in plasma
  3. Cytokines levels in plasma:

    1. interferon-γ that can induce some components of class I MHC (9).
    2. tumor necrosis factor-α that influences the AMPAR expression and plays a role in LTP reduction (10).

Groups (of 20 people each) will make patients with a priori various degree of LTP/LTD balance: healthy people and PTSD patients.

People suffering PTSD, frequently have conditions when they again, brightly and deeply experience event injuring them. The memoirs painted by painful emotions, seize attention of the person and then it seems to him as if he again experiences injuring event and sees it as real.

We assume, that it is connected to the unable to induce reliable LTD, and that the composition of glutamate receptors and CD3-zeta expression in T-cells such people should differ from healthy.

Used method: enzyme- linked immunosorbent assay (ELISA), FACS

  Eligibility

Ages Eligible for Study:   18 Years to 60 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • male and female between 18-60 years
  • PTSD

Exclusion Criteria:

  • any immune system disease
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00396695

Contacts
Contact: Alexander Mizruchin, MD + 972 50 8434245
Contact: Igor Krasnov, Ph.D + 972 4 6828828 yehudit.h@ziv.health.gov.il

Locations
Israel
Sieff Government Hospital Recruiting
Safed, Israel, 13110
Contact: Igor Krasnov, Ph.D    + 972 4 682 8828      
Principal Investigator: Alexander Mizruchin, Ph.D         
Sub-Investigator: Igor Krasnov, Ph.D         
Sponsors and Collaborators
Ziv Hospital
Investigators
Principal Investigator: Alexander Mizruchin, MD Sieff Government Hospital
  More Information

Publications:
ClinicalTrials.gov Identifier: NCT00396695     History of Changes
Other Study ID Numbers: HP 6-198 R
Study First Received: November 6, 2006
Last Updated: November 6, 2006
Health Authority: Israel: Ministry of Health

Keywords provided by Ziv Hospital:
PTSD, traumatic memory

Additional relevant MeSH terms:
Stress Disorders, Post-Traumatic
Stress Disorders, Traumatic
Anxiety Disorders
Mental Disorders

ClinicalTrials.gov processed this record on October 30, 2014