Article
Doxycycline inhibits experimental cerebral malaria by altering T cell responses and reducing inflammatory and tissue-degrading mediators
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Published: | January 29, 2014 |
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We investigated the impact of doxycycline treatment on Plasmodium berghei ANKA (PbA) induced experimental cerebral malaria (ECM). The complex inflammatory networks triggerd by the parasite leads to the destruction of the blood brain barrier (BBB). Administration of doxycycline prevented neuropathology in PbA infected mice. Local inflammation was reduced to a minimum and BBB damage was prevented.
Other tetracyclie derivatives show similar protective effects, but only those with known immune-regulatory properties.
Our results provide evidence that the inhibition of ECM is to a large extend by anti-inflammatory actions of doxycycline, despite observed anti-parasitic effects. Protection is observed in high dose infected animals and likewise in animals receiving additional parasites later infection.
Analysing brain tissue by RNA-array and on protein levels, we found that in treated animals, the expression of CCL5, an important T cell recruitment factor in inflammation was reduced. Accordingly, T cell infiltration was impaired. The T cells accumulated in the spleen and despite similar activation compared to PbA infected controls, these cells showed reduced parasite-specific cytotoxicity after doxycycline treatment. In addition, ECM development could be associated with increased expression and activity of gelatinolytic MMP2, and cytolytic granzyme B in the brain, which were both reduced after doxycycline.
Our results suggest that during ECM in addition to known anti-parasitic effects several systemic and local inflammatory processes are targeted by doxycycline, inhibiting BBB disruption and neuropathology. Thus we provide theoretical support for retaining doxycycline in the treatment of severe human malaria.