Neuroinflammation as a Main Etiopathogenetic Factor in the Development of Drug-Resistant Epilepsies and Epileptic Encephalopathies

Abstract

Background: despite the large number of newly emerging antiepileptic drugs, the frequency of treatment-resistant forms of epilepsy has not decreased, averaging 25–30%. Moreover the number of epileptic encephalopathies of early childhood has increased. One of the reasons of drug resistance is neuroinflammation. Aim: to evaluate the role of neuroinflammation in the pathogenesis of severe forms of childhood epilepsy and resistant adult epilepsy.Patients and methods: the main group 1 — 94 pediatric patients with epileptic encephalopathies, average age 20.4 ± 6.2 months. The control group 1 — 42 pediatric patients in remission of epilepsy, average age 21.3 ± 5.7 months. The main group 2 — 35 adult patients with resistant forms of epilepsy, average age 38.3 ± 7.9 years. The control group 2 — adult patients in remission of epilepsy 47 patients, average age 34.2 ± 8.6 years. The following blood levels were analyzed: neuron-specific enolase, S100 protein, eosinophilic cationic protein, IgE total level, total level of circulating immune complexes, leukocyte elastase and alpha-1 antitrypsin. Results: in the group of children with epileptic encephalopathies, an increase in neuroinflammation indicators was revealed in most patients. The average level of neuron-specific enolase is 27.6 ± 5.3 ng/ml compared to 14.2 ± 3.5 ng/ml in the control group. The average S100 protein level is 0.232 ± 0.041 ng/ml compared to 0.092 ± 0.024 ng/ml in the control group. The average level of eosinophilic cationic protein is 39.7 ± 9.4 ng/ml compared with 18.2 ± 5.3 ng/ml in the control group. The average IgE level is 157.3 ± 64.2 IU/ml compared to 42.2 ± 17.5 IU/ml in the control group. The average level of circulating immune complexes is 265.6 ± 54.4 UE/ml compared to 56.8 ± 16.8 UE/ml in the control group. In the group of adult patients with resistant forms of epilepsy, an increase in neuroinflammation indicators was revealed in most patients. The average level of neuron-specific enolase is 19.2 ± 7.2 ng/ml compared to 13.1 ± 4.1 ng/ml in the control group. The average S100 protein level is 0.115 ± 0.037 ng/ml compared to 0.093 ± 0.018 ng/ml in the control group. The average level of eosinophilic cationic protein is 24.2 ± 6.7 ng/ml compared to 18.8 ± 4.7 ng/ml in the control group. The average level of total IgE is 117.9 ± 32.6 IU/ml compared to 53.4 ± 18.2 IU/ml in the control group. The average level of circulating immune complexes is 235.2 ± 43.7 UE/ml compared to 62.6 ± 20.4 UE/ml in the control group. The level of leukocyte elastase was increased in 32 (91.4%) patients, the average level was 267.2 ± 36.8 nmol/min × ml compared with 175.2 ± 23.8 nmol/min × ml in the control group. The level of alpha-1 antitrypsin was increased in 33 (94.3%) patients, the average level was 55.2 ± 12.1 ng/ml compared with 26.4 ± 15.6 ng/ml in the control group. Conclusion: neuroinflammation is the factor of the development of severe forms of epilepsy and the formation of resistance in epileptic encephalopathies. Epileptic encephalopathies of early childhood according to their etiopathogenesis should be considered as subacute encephalitis, where seizures are only one sign of the pathological inflammatory process. The main clinical aim of the treatment of epileptic encephalopathies is the diagnosis of cumulative antigenic load and the selection of anti-inflammatory therapy.