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Current antiepileptic strategies aim to normalize the interaction of the excitatory and inhibitory systems, which is ineffective in treating patients with drug-resistant epilepsy. Neuroinflammatory processes in the epileptic focus and its perifocal area can trigger apoptosis and also contribute to the development of drug resistance. The level of pro- and anti-apoptotic proteins (p-NF-kB, TNF-α, p53, FAS, caspase-3, caspase-9) was analyzed in intraoperative biopsies of the temporal lobe gray and white matter in the brain of patients with drug-resistant epilepsy. An increased level of pro-apoptotic proteins was revealed in the cortex and perifocal area’s white matter against the background of an imbalance of protective anti-apoptotic proteins. It appears that the activation of the extrinsic pathway of apoptosis occurs in the perifocal area, while in the epileptic focus, there are proteins responsible for the activation of the anti-apoptotic survival pathways. Active neuroinflammation in the epileptic focus and perifocal area of the temporal lobe may contribute to the development of the resistance to antiepileptic drugs and the progression of neurodegeneration in such patients.

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Neuroglial apoptosis and neuroinflammation play an important role in epileptogenesis. The aim of this study is to evaluate neuronal and glial apoptosis in association with neuroinflammation in brain epileptic focus and inflammatory changes in blood in patients with focal drug-resistant epilepsy (DRE). Pathological changes in the temporal lobe in epilepsy (histology, transmission electron microscopy), levels of apoptotic and neuroinflammatory proteins: active caspase-3 (immunohistochemistry), full-length form caspase-3, caspase-9, FAS, FAS-L, NF-kB, TNF-α, p53 (Western blot), and cytokine levels in blood: IL-1β, IL-2, IL-4, IL-7, TNF-α, etc. (multiplex analysis) were studied. In the present work, ultrastructural and immunohistochemical apoptotic signs were found in neurons and oligodendrocytes in the temporal lobe of DRE patients. Levels of proinflammatory cytokines that play a role in apoptosis (TNF-α, FAS, NF-kB) were increased. The blood concentration of IL-4, IL-7, TNF-α is increased and IL-2 is reduced. Oligodendroglial apoptosis has been shown to play an important role in DRE pathogenesis and to explain demyelination. Thus, a comprehensive analysis of revealed changes in the blood and brain in DRE patients showed the neuroinflammation in the epileptic focus, which was combined with the development of apoptosis of glial cells and neurons. This creates conditions for the development of drug resistance and the epilepsy progression.

Aim. To study markers of blood-brain barrier dysfunction (BBB) in patients with pharmacoresistant epilepsy (PhRE) – the amount of VEGF in endotheliocytes of brain capillaries, TNF-α in brain tissue and cytokine profile in blood serum.Materials and methods. The study included 30 patients with PhRE who underwent anterior temporal bloc resection. Histological samples of the brain were examined to assess the amount of VEGF and TNF-α; the concentration of cytokines in the blood serum was determined.Results. In the PhRE group, the densitometric density of cells expressing VEGF and the amount of TNF-α in the epileptogenic focus were higher than in the control groups (p < 0.001; p < 0.05). Compared with the control, the serum concentrations of IL-2 (0.98 ± 0.28 pg/ml vs. 2.80 ± 0.71 pg/ml; p < 0.001), IL-8 (14.04 ± 1.46 pg/ml vs. 26.13 ± 3.80 pg/ml; p < 0.001) and EGF (43.72 ± 5.63 pg/ml vs. 83.62 ± 24.06 pg/ml; p < 0.05) were statistically significantly lower in the PhRE group, and the amount of TNF-α (33.09 ± 1.23 pg/ml vs. 24.85 ± 1.32 pg/ml, p < 0.05), IL-4 (43.73 ± 2.57 pg/ml vs. 32.37 ± 5.80 pg/ml, p < 0.05), IL-5 (43.73 ± 2.57 pg/ml vs. 32.37 ± 5.80 pg/ml; p < 0.05), IL-7 (16.65 ± 3.07 pg/ml vs. 8.13 ± 1.67 pg/ml; p < 0.05), GRO (growth-regulated protein) (3054.0 ± 200.8 pg/ml vs. 1367.0 ± 187.3 pg/ml; p < 0.001), VEGF (316.10 ± 55.28 pg/ml vs. 95.22 ± 15.78 pg/ml; p < 0.01) are statistically significantly higher. There were no significant differences in the concentration of IL-1β, IL-1RA, IL-10 and IFN-γ between the PhRE group and the control.Conclusion. Based on the studied cytokine profile, there is no systemic inflammation in patients with PhRE. The established overexpression of VEGF in the brain and an increase in its concentration in the blood, combined with a decrease in serum EGF concentrations and an increase in GRO, as well as pro-inflammatory factors, indicates damage to the BBB. A high amount of TNF-α in the epileptic focus indicates neuroinflammation, and an increased concentration of this marker can be found in the blood of patients with BBB dysfunction.

Molecular cytogenetic and cytogenomic studies have made a contribution to genetics of epilepsy. However, current genomic research of this devastative condition is generally focused on the molecular genetic aspects (i.e. gene hunting, detecting mutations in known epilepsy-associated genes, searching monogenic causes of epilepsy). Nonetheless, chromosomal abnormalities and copy number variants (CNVs) represent an important part of genetic defects causing epilepsy. Moreover, somatic chromosomal mosaicism and genome/chromosome instability seem to be a possible mechanism for a wide spectrum of epileptic conditions. This idea becomes even more attracting taking into account the potential of molecular neurocytogenetic (neurocytogenomic) studies of the epileptic brain. Unfortunately, analyses of chromosome numbers and structure in the affected brain or epileptogenic brain foci are rarely performed. Therefore, one may conclude that cytogenomic area of genomic epileptology is poorly researched. Accordingly, molecular cytogenetic and cytogenomic studies of the clinical cohorts and molecular neurocytogenetic analyses of the epileptic brain appear to be required. Here, we have performed a theoretical analysis to define the targets of the aforementioned studies and to highlight future directions for molecular cytogenetic and cytogenomic research of epileptic disorders in the widest sense. To succeed, we have formed a consortium, which is planned to perform at least a part of suggested research. Taking into account the nature of the communication, “cytogenomic epileptology” has been introduced to cover the research efforts in this field of medical genomics and epileptology. Additionally, initial results of studying cytogenomic variations in the Russian neurodevelopmental cohort are reviewed with special attention to epilepsy. In total, we have concluded that (i) epilepsy-associated cytogenomic variations require more profound research; (ii) ontological analyses of epilepsy genes affected by chromosomal rearrangements and/or CNVs with unraveling pathways implicating epilepsy-associated genes are beneficial for epileptology; (iii) molecular neurocytogenetic (neurocytogenomic) analysis of postoperative samples are warranted in patients suffering from epileptic disorders.

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