Blocking human #fear memory with the matrix metalloproteinase inhibitor #doxycycline
http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201765a.html
Learning to predict threat is a fundamental ability of many biological organisms, and a laboratory model for anxiety disorders. Interfering with such memories in humans would be of high clinical relevance. On the basis of studies in cell cultures and slice preparations, it is hypothesised that synaptic remodelling required for threat learning involves the extracellular enzyme matrix metalloproteinase (MMP) 9. However, in vivo evidence for this proposal is lacking. Here we investigate human Pavlovian fear conditioning under the blood–brain barrier crossing MMP inhibitor doxycyline in a pre-registered, randomised, double-blind, placebo-controlled trial. We find that recall of threat memory, measured with fear-potentiated startle 7 days after acquisition, is attenuated by ~60% in individuals who were under doxycycline during acquisition. This threat memory impairment is also reflected in increased behavioural surprise signals to the conditioned stimulus during subsequent re-learning, and already late during initial acquisition. Our findings support an emerging view that extracellular signalling pathways are crucially required for threat memory formation. Furthermore, they suggest novel pharmacological methods for primary prevention and treatment of posttraumatic stress disorder.
http://www.nature.com/mp/journal/vaop/ncurrent/full/mp201765a.html
Learning to predict threat is a fundamental ability of many biological organisms, and a laboratory model for anxiety disorders. Interfering with such memories in humans would be of high clinical relevance. On the basis of studies in cell cultures and slice preparations, it is hypothesised that synaptic remodelling required for threat learning involves the extracellular enzyme matrix metalloproteinase (MMP) 9. However, in vivo evidence for this proposal is lacking. Here we investigate human Pavlovian fear conditioning under the blood–brain barrier crossing MMP inhibitor doxycyline in a pre-registered, randomised, double-blind, placebo-controlled trial. We find that recall of threat memory, measured with fear-potentiated startle 7 days after acquisition, is attenuated by ~60% in individuals who were under doxycycline during acquisition. This threat memory impairment is also reflected in increased behavioural surprise signals to the conditioned stimulus during subsequent re-learning, and already late during initial acquisition. Our findings support an emerging view that extracellular signalling pathways are crucially required for threat memory formation. Furthermore, they suggest novel pharmacological methods for primary prevention and treatment of posttraumatic stress disorder.
Nature
Molecular Psychiatry - Blocking human fear memory with the matrix metalloproteinase inhibitor doxycycline
Molecular Psychiatry publishes work aimed at elucidating biological mechanisms underlying psychiatric disorders and their treatment
Post-exposure prophylaxis with #doxycycline to prevent #sexually transmitted infections in men who have sex with men: an open-label randomised substudy of the ANRS IPERGAY trial
http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30725-9/fulltext
Between July 20, 2015, and Jan 21, 2016, we randomly assigned 232 participants (n=116 in the doxycycline PEP group and n=116 in the no-PEP group) who were followed up for a median of 8·7 months (IQR 7·8–9·7). Participants in the PEP group used a median of 680 mg doxycycline per month (IQR 280–1450). 73 participants presented with a new STI during follow-up, 28 in the PEP group (9-month probability 22%, 95% CI 15–32) and 45 in the no-PEP group (42%, 33–53; log-rank test p=0·007). The occurrence of a first STI in participants taking PEP was lower than in those not taking PEP (hazard ratio [HR] 0·53; 95% CI 0·33–0·85; p=0·008). Similar results were observed for the occurrence of a first episode of chlamydia (HR 0·30; 95% CI 0·13–0·70; p=0·006) and of syphilis (0·27; 0·07–0·98; p=0·047); for a first episode of gonorrhoea the results did not differ significantly (HR 0·83; 0·47–1·47; p=0·52). No HIV seroconversion was observed, and 72 (71%) of all 102 STIs were asymptomatic. Rates of serious adverse events were similar in the two study groups. Gastrointestinal adverse events were reported in 62 (53%) participants in the PEP group and 47 (41%) in the no-PEP group (p=0·05).
Interpretation
Doxycycline PEP reduced the occurrence of a first episode of bacterial STI in high-risk men who have sex with men
http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30725-9/fulltext
Between July 20, 2015, and Jan 21, 2016, we randomly assigned 232 participants (n=116 in the doxycycline PEP group and n=116 in the no-PEP group) who were followed up for a median of 8·7 months (IQR 7·8–9·7). Participants in the PEP group used a median of 680 mg doxycycline per month (IQR 280–1450). 73 participants presented with a new STI during follow-up, 28 in the PEP group (9-month probability 22%, 95% CI 15–32) and 45 in the no-PEP group (42%, 33–53; log-rank test p=0·007). The occurrence of a first STI in participants taking PEP was lower than in those not taking PEP (hazard ratio [HR] 0·53; 95% CI 0·33–0·85; p=0·008). Similar results were observed for the occurrence of a first episode of chlamydia (HR 0·30; 95% CI 0·13–0·70; p=0·006) and of syphilis (0·27; 0·07–0·98; p=0·047); for a first episode of gonorrhoea the results did not differ significantly (HR 0·83; 0·47–1·47; p=0·52). No HIV seroconversion was observed, and 72 (71%) of all 102 STIs were asymptomatic. Rates of serious adverse events were similar in the two study groups. Gastrointestinal adverse events were reported in 62 (53%) participants in the PEP group and 47 (41%) in the no-PEP group (p=0·05).
Interpretation
Doxycycline PEP reduced the occurrence of a first episode of bacterial STI in high-risk men who have sex with men
The Lancet Infectious Diseases
Post-exposure prophylaxis with doxycycline to prevent sexually transmitted infections in men who have sex with men: an open-label…
Doxycycline PEP reduced the occurrence of a first episode of bacterial STI in high-risk
men who have sex with men.
men who have sex with men.