Valproic acid attenuates ischemia-reperfusion injury in the rat brain through inhibition of oxidative stress and inflammation

Decreased GFAP expression and improved functional recovery in contused spinal cord of rats following valproic acid therapy

Many studies have illustrated that much of the post-traumatic degeneration of the spinal cord cells is caused by the secondary mechanism. The aim of this study is to evaluate the effect of the anti-inflammatory property of valproic acid (VPA) on injured spinal cords (SC). The rats with the contused SC received intraperitoneal single injection of VPA (150, 200, 300, 400 or 500 mg/kg) at 2, 6, 12 and 24 h post-injury. Basso-Beattie-Bresnahan (BBB) test and H-reflex evaluated the functional outcome for 12 weeks. The SC were investigated 3 months post-injury using morphometry and glial fibrillary acid protein (GFAP) expression. Reduction in cavitation, H/M ratio, BBB scores and GFAP expression in the treatment groups were significantly more than that of the untreated one (P < 0.05). The optimal improvement in the condition of the contused rats was in the ones treated at the acute phase of injury with 300 mg/kg of VPA at 12 h post-injury, they had the highest increase in BBB score and decrease in astrogliosis and axonal loss. We conclude that treating the contused rats with 300 mg/kg of VPA at 12 h post-injury improves the functional outcome and reduces the traumatized SC gliosis.

The anti-seizure drugs vinpocetine and carbamazepine, but not valproic acid, reduce inflammatory IL-1β and TNF-α expression in rat hippocampus

In the present study, the effects of the two classical anti-epileptic drugs, carbamazepine and valproic acid, and the non-classical anti-seizure drug vinpocetine were investigated on the expression of the pro-inflammatory cytokines IL-1β and TNF-α in the hippocampus of rats by PCR or western blot after the administration of one or seven doses. Next, the effects of the anti-seizure drugs were investigated on the rise in cytokine expression induced by lipopolysaccharides (LPS) inoculation in vivo. To validate our methods, the changes induced by the pro-convulsive agents 4-aminopyridine, pentylenetetrazole and pilocarpine were also tested. Finally, the effect of the anti-seizure drugs on seizures and on the concomitant rise in pro-inflammatory cytokine expression induced by 4-aminopyridine was explored. Results show that vinpocetine and carbamazepine reduced the expression of IL-1β and TNF-α from basal conditions, and the increase in both pro-inflammatory cytokines induced by LPS. In contrast, valproic acid failed to reduce both the expression of the cytokines from basal conditions and the rise in IL-1β and TNF-α expression induced by LPS. Tonic-clonic seizures induced either by 4-aminopyridine, pentylenetetrazole or pilocarpine increased the expression of IL-1β and TNF-α markedly. 4-aminopyridine-induced changes were reduced by all the tested anti-seizure drugs, although valproic acid was less effective. We conclude that the anti-seizure drugs, vinpocetine and carbamazepine, whose mechanisms of action involve a decrease in ion channels permeability, also reduce cerebral inflammation. The mechanism of action of anti-seizure drugs like vinpocetine and carbamazepine involves a decrease in Na(+) channels permeability. We here propose that this mechanism of action also involves a decrease in cerebral inflammation.

Valproic acid enhances the effect of bone marrow-derived mononuclear cells in a rat ischemic stroke model

Bone marrow derived mononuclear cell (MNC) transplantation is a potential therapy for ischemic stroke. Here, we hypothesized that valproic acid (VPA) would modulate transplantation effects of MNCs in a rat ischemic stroke model. Male Sprague-Dawley rats were subjected to transient 90min middle cerebral artery occlusion. Infarct volume, neurological outcome, and immunohistological assessments were performed 7 days after ischemia. MNCs injected 6 or 24h but not 48 or 72h after ischemia significantly reduced infarct volume and improved neurological deficits. We then tested whether the therapeutic window of MNC transplantation could be expanded through combination therapy with VPA. MNC transplantation at 48h combined with VPA injection three times at 47, 53, and 72h after ischemia significantly ameliorated infarct volume and neurological deficits compared to a vehicle group. Combination therapy reduced the number of myeloperoxidase-positive cells, ionized calcium binding adapter molecule 1-positive cells, tumor necrosis factor-α-positive cells, and von Willebrand factor-positive cells in the ischemic boundary zone. The number of engrafted MNCs that were fluorescently labeled with PKH 26, on day 7, was significantly higher after combination therapy than after that MNC transplantation alone. Our results demonstrated that combination therapy with VPA enhanced the anti-inflammatory and vasculo-protective effects against endothelial damage following ischemia, and increased the survival of transplanted cells, leading to expansion of the therapeutic time window for MNC transplantation. Together, these findings suggest that VPA may be an appropriate partner for cell-based treatment of ischemic stroke.

Valproate reverts zinc and potassium imbalance in schizophrenia-derived reprogrammed cells

Schizophrenia has been considered a devastating clinical syndrome rather than a single disease. Nevertheless, the mechanisms behind the onset of schizophrenia have been only partially elucidated. Several studies propose that levels of trace elements are abnormal in schizophrenia; however, conflicting data generated from different biological sources prevent conclusions being drawn. In this work, we used synchrotron radiation X-ray microfluorescence spectroscopy to compare trace element levels in neural progenitor cells (NPCs) derived from two clones of induced pluripotent stem cell lines of a clozapine-resistant schizophrenic patient and two controls. Our data reveal the presence of elevated levels of potassium and zinc in schizophrenic NPCs. Neural cells treated with valproate, an adjunctive medication for schizophrenia, brought potassium and zinc content back to control levels. These results expand the understanding of atomic element imbalance related to schizophrenia and may provide novel insights for the screening of drugs to treat mental disorders.

Modulation of cytokine production by drugs with antiepileptic or mood stabilizer properties in anti-CD3- and anti-Cd40-stimulated blood in vitro

Increased cytokine production possibly due to oxidative stress has repeatedly been shown to play a pivotal role in the pathophysiology of epilepsy and bipolar disorder. Recent in vitro and animal studies of valproic acid (VPA) report antioxidative and anti-inflammatory properties, and suppression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. We tested the effect of drugs with antiepileptic or mood stabilizer properties, namely, primidone (PRM), carbamazepine (CBZ), levetiracetam (LEV), lamotrigine (LTG), VPA, oxcarbazepine (OXC), topiramate (TPM), phenobarbital (PB), and lithium on the production of the following cytokines in vitro: interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-17, IL-22, and TNF-α. We performed a whole blood assay with stimulated blood of 14 healthy female subjects. Anti-human CD3 monoclonal antibody OKT3, combined with 5C3 antibody against CD40, was used as stimulant. We found a significant reduction of IL-1 and IL-2 levels with all tested drugs other than lithium in the CD3/5C3-stimulated blood; VPA led to a decrease in IL-1β, IL-2, IL-4, IL-6, IL-17, and TNF-α production, which substantiates and adds knowledge to current hypotheses on VPA's anti-inflammatory properties.

Valproic acid: a new candidate of therapeutic application for the acute central nervous system injuries

Acute central nervous system (CNS) injuries, including stroke, traumatic brain injury (TBI), and spinal cord injury (SCI), are common causes of human disabilities and deaths, but the pathophysiology of these diseases is not fully elucidated and, thus, effective pharmacotherapies are still lacking. Valproic acid (VPA), an inhibitor of histone deacetylation, is mainly used to treat epilepsy and bipolar disorder with few complications. Recently, the neuroprotective effects of VPA have been demonstrated in several models of acute CNS injuries, such as stroke, TBI, and SCI. VPA protects the brain from injury progression via anti-inflammatory, anti-apoptotic, and neurotrophic effects. In this review, we focus on the emerging neuroprotective properties of VPA and explore the underlying mechanisms. In particular, we discuss several potential related factors in VPA research and present the opportunity to administer VPA as a novel neuropective agent.

Histone deacetylase inhibitors decrease intra-abdominal adhesions with one intraoperative dose by reducing peritoneal fibrin deposition pathways

BACKGROUND

We previously demonstrated that postoperative peritoneal injury and inflammation contribute to adhesiogenesis. Recent evidence suggests that in addition to their role of interfering with the acetylation status of nuclear histone proteins, histone deacetylase inhibitors (HDACIs) including valproic acid (VPA) can target nonhistone proteins to resolve inflammation and modulate immune cells. We hypothesized that HDACIs could reduce adhesions.

METHODS

Seventy-two rats underwent laparotomy with creation of 6 peritoneal ischemic buttons to induce adhesions. A single intraperitoneal (IP) dose of 50 mg/kg VPA was administered intraoperatively, whereas controls received vehicle. To evaluate the timing, 25 rats underwent ischemic button creation with either an intraoperative or a delayed IP dose of VPA at 1, 3, or 6 hours postoperatively. On postoperative day 7, adhesions were quantified. To investigate mechanisms, ischemic buttons were created in 24 rats and either VPA or saline was administered in 1 intraoperative dose. At 3 or 24 hours later, peritoneal fluid was collected and fibrinolytic activity measured. Alternatively, button tissue was collected 30 minutes postoperatively to measure tissue factor, fibrinogen, and vascular endothelial growth factor (VEGF) by real-time polymerase chain reaction or Western blot.

RESULTS

A single intraoperative dose of VPA reduced adhesions by 50% relative to controls (P < .001). Delayed dosing did not reduce adhesions. In operated animals, peritoneal fibrinolytic activity was not different between groups. Tissue factor mRNA was downregulated by 50% (P = .02) and protein by 34% (P < .01) in animals administered VPA versus saline. VPA decreased fibrinogen protein by 56% and VEGF protein by 25% compared with saline (P = .03).

CONCLUSION

These findings suggest that VPA rapidly reduces the extravasation of key adhesiogenic substrates into the peritoneum. A single, intraoperative intervention provides an ideal dosing strategy and indicates an exciting new role for HDACIs in adhesion prevention.