Highly active antiretroviral treatment against STLV-1 infection combining reverse transcriptase and HDAC inhibitors.

Approximately 3% of all human T-lymphotropic virus type 1 (HTLV-1)-infected persons will develop a disabling inflammatory disease of the central nervous system known as HTLV-1-associated myelopathy/tropical spastic paraparesis, against which there is currently no efficient treatment. As correlation exists between the proviral load (PVL) and the clinical status of the carrier, it is thought that diminishing the PVL could prevent later occurrence of the disease. We have conducted a study combining valproate, an inhibitor of histone deacetylases, and azidothymidine, an inhibitor of reverse transcriptase, in a series of baboons naturally infected with simian T-lymphotropic virus type 1 (STLV-1), whose PVL was equivalent to that of HTLV-1 asymptomatic carriers. We show that the combination of drugs caused a strong decrease in the PVL and prevented the transient rise in PVL that is seen after treatment with histone deacetylases alone. We then demonstrate that the PVL decline was associated with an increase in the STLV-1-specific cytotoxic T-cell population. We conclude that combined treatment with valproate to induce viral expression and azidothymidine to prevent viral propagation is a safe and effective means to decrease PVL in vivo. Such treatments may be useful to reduce the risk of HAM/TSP in asymptomatic carriers with a high PVL.

Functional cerebral venous outflow in swine and baboon: feasibility of an intracranial venous hypertension model.

INTRODUCTION: To evaluate the feasibility of performing a functional cerebral venous outflow blockage in two large animals species, the swine and the baboon, for elaboration of venous hypertension models. METHOD: Cerebral venous outflow pathways were identified on angiogram and venography of three swine and two baboons, and potential approaches to access these structures were assessed. Practicability of performing functional intracranial dural outflow blockage was tested. RESULTS: The main cerebral venous outflow route was the internal jugular vein in baboons and the paraspinal venous network in swine. Both animals had an additional venous outflow structure, the petrosquamous sinus. Access to intracranial venous sinuses was achieved through a percutaneous retrograde approach in baboon but not in swine, due to the absence of a direct connection between the dural structures and the internal jugular vein. A transcranial approach allowed to access dural venous structures in swine. In both models, partial and progressive venous sinus occlusion increased intracranial pressure, while preserving the animal's vital status. At 6 months, all animals are alive with no neurological deficits. CONCLUSION: Functional venous dural outflow blockage for elaboration of intracranial venous hypertension is feasible in both models. To be effective, the sinus blockage must be performed before the origin of the petrosquamous, an additional venous sinus seen in swine and baboon. The baboon has the greatest advantage of resembling human cerebral venous drainage, which enables an intracranial venous retrograde access. However, the transcranial approach remains a valuable option to access intracranial venous sinuses in swine.