Combination Therapy of Gabapentin and N-Acetylcysteine Against Posttraumatic Epilepsy in Rats.

Traumatic brain injury (TBI) is a major public health problem worldwide that is associated with increased mortality and morbidity. Posttraumatic epilepsy (PTE) is one of the sequelae of TBI. The aim of this study was to investigate the role of N-acetylcysteine (NAC) as an adjuvant on the efficacy of levetiracetam (LEV) and gabapentin (GBP) in PTE model encouraged by pentylenetetrazol (PTZ) after mild-TBI in male Sprague-Dawley rats. Mild-TBI was performed by the weight-drop method in male Sprague-Dawley rats. PTE model was developed by injecting PTZ (30+15+15 mg/kg, 30 min intervals, i.p.) 7 days after head trauma. After the development of posttraumatic seizures, the rats were treated with NAC (100 mg/kg), LEV (50 mg/kg), GBP (100 mg/kg), NAC+LEV and NAC+GBP intraperitoneally for 14 days. Seizures related to PTE were scored by video-EEG recording. Motor performance of the animals was also evaluated in the rotarod test. 50 mg/kg LEV and 100 mg/kg GBP reduced seizures related to PTE. LEV alone (p = 0.009), but the administration of GBP+NAC (p = 0.015) was more effective on PTE-related seizure control. However, GBP+NAC application adversely affected the fall latency in the rotarod test. In terms of trauma-related seizure control, there was no statistically significant difference between the use of prophylactic LEV and symptomatic LEV. LEV alone or the combination of GBP with NAC provides more effective seizure control in the PTE facilitated by PTZ. On the other hand, the use of prophylactic LEV did not have any extra effect on posttraumatic seizure development and control.

Potential therapeutic implications of ergogenic compounds on pathophysiology induced by traumatic brain injury: A narrative review.

Traumatic brain injury (TBI) is a devastating condition that often triggers a sequel of neurological disorders that can last throughout lifespan. From a metabolic viewpoint, the compromising of the energy metabolism of the brain has produced evidence linking the severity of brain injury to the extent of disturbances in the cerebral metabolism. The cerebral metabolic crisis, however, displays that regional heterogeneity varies temporally post-injury. It is important to note that energy generation and mitochondrial function are closely related and interconnected with delayed secondary manifestations of brain injury, including early neuromotor dysfunction, cognitive impairment, and post-traumatic epilepsy (PTE). Given the extent of post-traumatic changes in neuronal function and the possibility of amplifying secondary cascades, different therapies designed to minimize damage and retain/restore cellular function after TBI are currently being studied. One of the possible strategies may be the inclusion of ergogenic compounds, which is a class of supplements that typically includes ingredients used by athletes to enhance their performance. The combination of these compounds offers specific physiological advantages, which include enhanced energy availability/metabolism and improved buffering capacity. However, the literature on their effects in certain biological systems and neurological diseases, such as TBI, has yet to be determined. Thus, the present review aims to discuss the role of ergogenic compounds popularly used in secondary damage induced by this neurological injury. In this narrative review, we also discuss how the results from animal studies can be applied to TBI clinical settings.

Disease-modifying effect of atipamezole in a model of post-traumatic epilepsy.

Treatment of TBI remains a major unmet medical need, with 2.5 million new cases of traumatic brain injury (TBI) each year in Europe and 1.5 million in the USA. This single-center proof-of-concept preclinical study tested the hypothesis that pharmacologic neurostimulation with proconvulsants, either atipamezole, a selective α2-adrenoceptor antagonist, or the cannabinoid receptor 1 antagonist SR141716A, as monotherapy would improve functional recovery after TBI. A total of 404 adult Sprague-Dawley male rats were randomized into two groups: sham-injured or lateral fluid-percussion-induced TBI. The rats were treated with atipamezole (started at 30min or 7 d after TBI) or SR141716A (2min or 30min post-TBI) for up to 9 wk. Total follow-up time was 14 wk after treatment initiation. Outcome measures included motor (composite neuroscore, beam-walking) and cognitive performance (Morris water-maze), seizure susceptibility, spontaneous seizures, and cortical and hippocampal pathology. All injured rats exhibited similar impairment in the neuroscore and beam-walking tests at 2 d post-TBI. Atipamezole treatment initiated at either 30min or 7 d post-TBI and continued for 9 wk via subcutaneous osmotic minipumps improved performance in both the neuroscore and beam-walking tests, but not in the Morris water-maze spatial learning and memory test. Atipamezole treatment initiated at 7 d post-TBI also reduced seizure susceptibility in the pentylenetetrazol test 14 wk after treatment initiation, although it did not prevent the development of epilepsy. SR141716A administered as a single dose at 2min post-TBI or initiated at 30min post-TBI and continued for 9 wk had no recovery-enhancing or antiepileptogenic effects. Mechanistic studies to assess the α2-adrenoceptor subtype specificity of the disease-modifying effects of atipametzole revealed that genetic ablation of α2A-noradrenergic receptor function in Adra2A mice carrying an N79P point mutation had antiepileptogenic effects after TBI. On the other hand, blockade of α2C-adrenoceptors using the receptor subtype-specific antagonist ORM-12741 had no favorable effects on the post-TBI outcome. Finally, to assess whether regulation of the post-injury inflammatory response by atipametzole in glial cells contributed to a favorable outcome, we investigated the effect of atipamezole on spontaneous and/or lipopolysaccharide-stimulated astroglial or microglial cytokine release in vitro. We observed no effect. Our data demonstrate that a 9-wk administration of α2A-noradrenergic antagonist, atipamezole, is recovery-enhancing after TBI.

[Neuroprotection in epilepsy].

Brain damage and neuronal loss caused by traumatic brain injury, ischemic stroke, and symptomatic status epilepticus can lead to severe long-term consequences, such as impairment in learning and memory and cognitive functions, and development of chronic epilepsy. This can be the result of morphologic and functional changes underlying temporal lobe epilepsy. Epilepsy patients have increased risk of status epilepticus. It is a life-threatening condition when seizures last for more than 30 min and trigger processes leading to neuronal apoptosis and necrosis in various parts of brain. Administration of neuroprotective drugs preventing these pathologic processes could improve the prognosis for such patients. However despite of active research of neuroprotective drugs, the effective ways to prevent brain damage resulting from prolonged seizures are yet to be found. Studies of neuroprotective properties of classic and novel anticonvulsant drugs showed that most of them do not have the sufficient neuroprotective effect and are not able to prevent epileptogenesis. Thus the studies of other potential neuroprotective drugs seem to be promising.

Preventing and treating posttraumatic seizures: the human experience.

Posttraumatic epilepsy presents an ideal target for prevention efforts. Traumatic brain injury (TBI) is common, characteristics that put people at high risk such as penetrating injury or subdural hematoma or provoked seizures are easily identified, and the latency between the injury and the onset of epileptic seizures is frequently short. Several drugs have been tested for their ability to prevent provoked seizures and epilepsy after TBI. We describe the design of those studies and their results. Phenytoin and carbamazepine significantly reduce the incidence of provoked seizures. Phenobarbital and the combination of phenobarbital and phenytoin also look promising for reducing provoked seizures, but small sample sizes in the studies evaluating these drugs do not allow definitive conclusions. None of the drugs studied (phenytoin, phenobarbital, their combination, carbamazepine, valproate, or magnesium) have shown reliable evidence that they prevent, or even suppress, epileptic seizures after TBI. For most of the regimens tested (the phenytoin/phenobarbital combination being the exception), the best estimate of effect is under a 25% reduction in posttraumatic seizures, well less than the 50% reduction most studies were designed to detect. The evaluation of the tested drugs has serious limitations, however, and antiepileptic drugs (AEDs) developed since 1980 and other compounds have barely been tested at all. Better understanding the process of epileptogenesis, testing treatments that demonstrate antiepileptogenic effects in the laboratory, and performing thorough preclinical and phase II evaluations before attempting definitive trials should greatly improve the chance of identifying ways to prevent posttraumatic epilepsy, providing the ultimate cure for this condition.