Interfering with the reconsolidation of traumatic memory: Sirolimus as a novel agent for treating veterans with posttraumatic stress disorder.
ABSTRACT Development of novel treatment approaches for combat-related posttraumatic stress disorder (PTSD) is critical, given the increasing prevalence of PTSD in veterans returning from war zone deployment. Established preclinical research using protein synthesis inhibitors (such as sirolimus) to interfere with fear memory reconsolidation provides a compelling rationale for investigation in humans.
This double-blind, placebo-controlled translational pilot study examined the effects of pairing reactivation of a trauma memory with a single administration of sirolimus on the frequency and intensity of PTSD symptoms in male combat veterans.
Primary analyses found no significant differences between treatment groups on any of the clinical or physiologic outcome measures. In an exploratory analysis of a subsample of post-Vietnam-era veterans who had more recent combat trauma, PTSD symptom scores fell significantly more in these veterans than in controls.
The post-Vietnam-era veteran findings suggest that further investigation of this pairing of sirolimus with traumatic memory reactivation may be warranted. Theoretically, interference with the reconsolidation of fear memories could ameliorate military-related psychological trauma symptoms. Future research should focus on veterans of more recent eras whose traumatic memories may be less entrenched and more amenable to pharmacologic modification within this procedure.
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ABSTRACT: The psychometric properties of the PTSD Checklist (PCL), a new, brief, self-report instrument, were determined on a population of 40 motor vehicle accident victims and sexual assault victims using diagnoses and scores from the CAPS (Clinician Administered PTSD Scale) as the criteria. For the PCL as a whole, the correlation with the CAPS was 0.929 and diagnostic efficiency was 0.900 versus CAPS. Examination of the individual items showed wide ranging values of individual item correlations ranging from 0.386 to 0.788, and with diagnostic efficiencies of 0.700 or better for symptoms. We support the value of the PCL as a brief screening instrument for PTSD.Behaviour Research and Therapy 09/1996; 34(8):669-73.
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ABSTRACT: 'New' memories are initially labile and sensitive to disruption before being consolidated into stable long-term memories. Much evidence indicates that this consolidation involves the synthesis of new proteins in neurons. The lateral and basal nuclei of the amygdala (LBA) are believed to be a site of memory storage in fear learning. Infusion of the protein synthesis inhibitor anisomycin into the LBA shortly after training prevents consolidation of fear memories. Here we show that consolidated fear memories, when reactivated during retrieval, return to a labile state in which infusion of anisomycin shortly after memory reactivation produces amnesia on later tests, regardless of whether reactivation was performed 1 or 14 days after conditioning. The same treatment with anisomycin, in the absence of memory reactivation, left memory intact. Consistent with a time-limited role for protein synthesis production in consolidation, delay of the infusion until six hours after memory reactivation produced no amnesia. Our data show that consolidated fear memories, when reactivated, return to a labile state that requires de novo protein synthesis for reconsolidation. These findings are not predicted by traditional theories of memory consolidation.Nature 09/2000; 406(6797):722-6. DOI:10.1038/35021052
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ABSTRACT: A phase I study was conducted to determine the pharmacokinetics, safety, and tolerability of sirolimus, a new immunosuppressive drug, in 45 healthy men between 19 and 36 years of age. Nine subjects in each group were randomly assigned to receive single oral doses of either sirolimus (n = 6) or placebo (n = 3) in group I (0.3 mg/m2), group II (1 mg/m2), group III (3 mg/m2), group IV (5 mg/m2) and group V (8 mg/m2). No serious adverse events occurred during the study. Twenty-eight of the 45 volunteers (62%) reported an adverse event; 19 of 30 (63%) were in the sirolimus group and 9 of 15 (60%) were in the placebo group (ns). Asthenia was the most common adverse event, occurring in 7 of 30 (23%) in the sirolimus group compared with 6 of 15 (40%) in the placebo group (ns). Absorption occurred within 1 hour in all volunteers. Whole blood peak concentration and area under the concentration-time curve increased proportionally with dose. Mean (+/- SD) whole blood terminal disposition half-life (t1/2), apparent oral dose clearance (Cl/F), and volume of distribution (Vss/F) were 82 +/- 12 hours, 278 +/- 117 mL/h x kg and 23 +/- 10 L/kg, respectively. Distribution of sirolimus into formed blood elements was extensive, with a mean whole blood-to-plasma ratio of 36. Single oral doses of sirolimus (0.3 to 8 mg/m2) solution were well tolerated in healthy male volunteers.Therapeutic Drug Monitoring 11/2000; 22(5):537-44. DOI:10.1097/00007691-200010000-00006