Tauroursodeoxycholic Acid (TUDCA) Regulates Inflammation and Hypoxia in Autonomic Tissues of Rats with Seizures.

Inflammation and hypoxia have an effect on the molecular mechanism of cardiovascular and respiratory pathologies accompanying seizures. Against this, Tauroursodeoxycholic Acid (TUDCA) can regulate oxidative stress, inflammation and cellular survival by suppressing endoplasmic reticulum (ER) stress. We evaluated the expression changes of NF-κB p65, TNF-α, HIF1α and Kir6.2 proteins associated with seizures in brain stem, heart and lung tissues representing the autonomous network. Additionally, we examined the protective effects of TUDCA administration against damage caused by seizures in terms of immunohistochemistry and pathology. 4 groups of Wistar Albino male rats (250-300 g, n=32) were formed as control, pentylenetetrazole (PTZ), TUDCA and PTZ+TUDCA. The epilepsy kindling model was created by intraperitoneal (i.p.) injection of PTZ chemical (35 mg/kg, every 2 days) for one month. TUDCA (500 mg/kg; every 2 days) treatment was given intraperitoneally 30 minutes before seizures for 1 month. Brain stem, heart (atria, ventricle) and lung tissues of rats were isolated. NF-κB p65, TNF-α, HIF1α and Kir6.2 proteins in the obtained tissues were evaluated by immunohistochemical staining. The immunoreactivity of the investigated proteins in the brainstem heart and lung tissues of rats with chronic PTZ administration was significantly increased. Recurrent seizures led to accumulation of inflammatory cells in tissues, hemorrhage, vasodilation, and apoptosis. Following TUDCA administration, expression of NF-κB p65, TNF-α and Kir6.2 was significantly reduced in all tissues (except the atrium of the heart) compared to control rats. HIF-1α levels were significantly suppressed in ventricular and lung tissues of epileptic rats given TUDCA. However, TUDCA pretreatment improved histopathological changes due to chronic seizures and partially reduced apoptosis. We showed that epileptic seizures may cause tissue damage with the development of inflammatory and hypoxic conditions in the brainstem and organs that represent the autonomic network. TUDCA therapy could be an effective agent in the treatment of cardiac and respiratory problems associated with seizures.

Envisioning the role of inwardly rectifying potassium (Kir) channel in epilepsy.

Epilepsy is a devastating neurological disorder characterized by recurrent seizures attributed to the disruption of the dynamic excitatory and inhibitory balance in the brain. Epilepsy has emerged as a global health concern affecting about 70 million people worldwide. Despite recent advances in pre-clinical and clinical research, its etiopathogenesis remains obscure, and there are still no treatment strategies modifying disease progression. Although the precise molecular mechanisms underlying epileptogenesis have not been clarified yet, the role of ion channels as regulators of cellular excitability has increasingly gained attention. In this regard, emerging evidence highlights the potential implication of inwardly rectifying potassium (Kir) channels in epileptogenesis. Kir channels consist of seven different subfamilies (Kir1-Kir7), and they are highly expressed in both neuronal and glial cells in the central nervous system. These channels control the cell volume and excitability. In this review, we discuss preclinical and clinical evidence on the role of the several subfamilies of Kir channels in epileptogenesis, aiming to shed more light on the pathogenesis of this disorder and pave the way for future novel therapeutic approaches.

Cardiorespiratory findings in epilepsy: A recent review on outcomes and pathophysiology.

Epilepsy is a debilitating disorder of uncontrollable recurrent seizures that occurs as a result of imbalances in the brain excitatory and inhibitory neuronal signals, that could stem from a range of functional and structural neuronal impairments. Globally, nearly 70 million people are negatively impacted by epilepsy and its comorbidities. One such comorbidity is the effect epilepsy has on the autonomic nervous system (ANS), which plays a role in the control of blood circulation, respiration and gastrointestinal function. These epilepsy-induced impairments in the circulatory and respiratory systems may contribute toward sudden unexpected death in epilepsy (SUDEP). Although, various hypotheses have been proposed regarding the role of epilepsy on ANS, the linking pathological mechanism still remains unclear. Channelopathies and seizure-induced damages in ANS-control brain structures were some of the causal/pathological candidates of cardiorespiratory comorbidities in epilepsy patients, especially in those who were drug resistant. However, emerging preclinical research suggest that neurotransmitter/receptor dysfunction and synaptic changes in the ANS may also contribute to the epilepsy-related autonomic disorders. Thus, pathological mechanisms of cardiorespiratory dysfunction should be elucidated by considering the modifications in anatomy and physiology of the autonomic system caused by seizures. In this regard, we present a comprehensive review of the current literature, both clinical and preclinical animal studies, on the cardiorespiratory findings in epilepsy and elucidate the possible pathological mechanisms of these findings, in hopes to prevent SUDEP especially in patients who are drug resistant.

Traumatic brain injury-induced peripheral damage: The dynamics of the inflammatory and autophagy pathway from acute to chronic stages.

INTRODUCTION: Traumatic brain injury (TBI) is one of the major causes of death and disability worldwide, and brings a huge burden on the quality of life of patients with TBI and the country's healthcare system. Peripheral organs, especially the kidney, and liver, may be affected by the onset of molecular responses following brain tissue damage. While secondary injury responses post TBI has been well studied in the brain, the effect/consequences of these responses in the peripheral organs have not yet been fully elucidated. Thus, our study aimed to investigate the immunoreactivity of these responses, particularly via proinflammatory cytokines and autophagy markers in the kidney and liver post-acute and chronic TBI. MATERIAL AND METHODS: Mild TBI (mTBI) and repetitive mTBI (r-mTBI) were induced in male and female 2-month-old Balb/c mice via the Marmarou weight-drop model. Liver and kidney tissues were sampled at 24 hours (acute) and 30 days (chronic) post TBI and subjected to histopathological and immunoreactivity analysis. RESULTS: Interleukin (IL)-6 levels were significantly increased in the male liver and kidney tissues in both TBI groups compared to the control group but were seen to be decreased in the female r-mTBI chronic liver and r-mTBI acute kidney. Tumor necrosis factor a (TNF-a) levels were found to increase only in the female r-mTBI chronic kidney tissue and mTBI chronic liver tissue. IL-1b levels were increased in the male and female r-mTBI liver tissues but decreased in the female mTBI kidney tissue. Inducible nitric oxide synthase (iNOS) levels were found to be significantly increased in the female mTBI acute and r-mTBI chronic kidney tissue and mTBI liver tissue, but decreased in the r-mTBI acute kidney and r-mTBI liver tissues. Beclin-1 levels were increased in male mTBI chronic and r-mTBI acute liver tissue but decreased in the r-mTBI chronic group. LC3A/B and P62/SQSTM1 levels were significantly increased in the female mTBI chronic and male r-mTBI chronic liver tissues but decreased in the male r-mTBI and female r-mTBI acute kidney tissues. Significant histopathological changes were also observed in the liver and kidney tissue which were dependent on the TBI severity, gender, and time post TBI. CONCLUSIONS: The results showed that TBI may elicit peripheral molecular responses, particularly in terms of alteration in the levels of inflammatory cytokines and autophagy markers, which were gender- and time-dependent. This suggests that TBI may have a significant role in the cellular damage of the kidney and liver in both the acute and chronic phases post TBI, thus ensuring that the effects of TBI may not be confined to the brain.

Increased ACh-Associated Immunoreactivity in Autonomic Centers in PTZ Kindling Model of Epilepsy.

Experimental and clinical studies of cardiac pathology associated with epilepsy have demonstrated an impact on the autonomic nervous system (ANS). However, the underlying molecular mechanism has not been fully elucidated. Molecular investigation of the neurotransmitters related receptor and ion channel directing ANS might help in understanding the associated mechanism. In this paper, we investigated the role of acetylcholine (ACh), which demonstrates both sympathetic and parasympathetic roles in targeted expression in terms of the relevant receptor and ion channel. Inwardly rectifying potassium (Kir) channels play a significant role in maintaining the resting membrane potential and controlling cell excitability and are prominently expressed in both the excitable and non-excitable tissues. The immunoreactivity of ACh-activated Kir3.1 channel and muscarinic ACh receptors (M2) in autonomic centers such as the brainstem, vagus nerve (VN) and atria of heart was confirmed by both histological staining and pathological tissue analysis. Significant upregulations of Kir3.1 and M2 receptors were observed in pentylenetetrazol (PTZ)-kindled epileptic rats for all related tissues investigated, whereas no pathological difference was observed. These findings provide proof-of-concept that changes in ACh-associated immunoreactivity might be linked to the ANS dysfunctions associated with epilepsy.