Epilepsy and gut microbiota

Epilepsy is a debilitating chronic disease that affects nearly 70 million people worldwide. Anti-seizure medications or anticonvulsants have been used as treatment measures to control seizures in patients with epilepsy. However, to date, there has not been an effective cure for epilepsy. In addition, one third of patients with epilepsy do not respond well to currently available anti-seizure medications, with some developing adverse effects such as sudden unexpected death in epilepsy (SUDEP). Over the past decade, gut dysbiosis has been strongly associated with various neurological disorders including epilepsy, where regulation of the intestinal microbes causing the dysbiosis may drastically improve seizure outcomes. Thus, this chapter aims to review the current literature on the interactive role of the gut microbiota in epilepsy. In patients with epilepsy, studies have showed that there was an upregulation of the immune-harmful bacteria phyla Firmicutes, Proteobacteria, Fusobacteria, and Verrucomicrobiota. In contrast, immune-beneficial bacterial species such as Bacteroidetes and Actinobacteria were downregulated in the gut of epileptic patients. Interestingly, altering these bacterial phyla or species levels in the gut or modulating the gut bacterial composition via ketogenic diet, probiotics, or fecal microbiota transplantation has shown positive improvements in seizures frequency and strength, especially in preclinical models. Although further studies may be warranted to determine the effectiveness of these treatment strategies in patients with epilepsy, current evidence suggests that the gut microbiota may serve as a good target for diagnosis, prognosis, and therapeutic intervention in them, thereby helping patients with epilepsy to lead a better quality of life.