sec-Butylpropylacetamide (SPD), a new amide derivative of valproic acid for the treatment of neuropathic and inflammatory pain

Bee venom ameliorates oxidative stress and histopathological changes of hippocampus, liver and testis during status epileptics

The unrelenting progression of neurodegenerative diseases has a negative impact on affected individuals, their families, and society. Recurrent epileptic seizures are the hallmark of epilepsy, and treating it effectively remains difficult. Clarify and understanding effects of the antiepileptic drugs (AEDs) in epilepsy by comparing the therapeutic effects between rats receiving valproic acid (VPA) and Bee venom (BV) was aimed throughout the present study. Four male Wistar rat groups were included: control, epileptic group receiving pilocarpine (PILO), epileptic group treated with VPA and BV respectively. Cognitive functions were assessed by evaluating latency time in hot plate, despair swim test, grooming, rearing and ambulation frequency in the open field. BV has ameliorative effect on electrolytes balancing, assured by decreasing lipid peroxidation, nitric oxide and increasing catalase, superoxide dismutase and glutathione peroxidase activities. BV enhanced restoration of liver functions indicated by alanine transaminase (ALT) and aspartate transaminase (AST), total proteins, and albumin; hormonal parameters total and free testosterone, follicle stimulating hormone (FSH) and Luteinizing hormone (LH) were preserved by BV with great recovery of hippocampus, liver and testicular histopathology and ultrastructure comparing with the epileptic rats. The present findings suggested that BV and its active components offer fresh options for controlling epilepsy and prospective methods via minimize or manage the severe consequences.

Identification of autophagy-related genes in neuropathic pain through bioinformatic analysis

BACKGROUND

Neuropathic pain (NP) is one of the most common types of chronic pain and significantly compromises the quality of life. Autophagy is an intracellular catabolic process that is required to maintain cellular homeostasis in response to various stresses. The role of autophagy-related genes in the diagnosis and treatment of neuropathic pain remains unclear.

METHODS

We identified autophagy-related differentially expressed genes (ARDEGs) and differentially expressed miRNAs (DE-miRNAs) in neuropathic pain by bioinformatics analysis of the GSE145226 and GSE145199 datasets. These ARDEGs and their co-expressed genes were subjected to Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, Gene Set Enrichment Analysis (GSEA) and friends analysis. Meanwhile, we constructed TFs-ARDEGs, miRNA-ARDEGs regulatory network through ChIPBase database and the HTFtarget database, multiMir R package. Finally, we performed immune infiltration analysis of ARDEGs by Single Sample Gene Set Enrichment Analysis (ssGSEA).

RESULTS

We identified 2 potential autophagy-related differentially expressed genes (Sirt2 and ST7) that may be closely associated with the pathogenesis of neuropathic pain. GO, KEGG and GSEA analysis revealed that these two ARDEGs were mainly enriched in pyridine nucleotide metabolic process, nicotinamide nucleotide metabolic process, Nicotinate and nicotinamide metabolism, NF-κB pathway, KRAS signaling, P53 pathway. In the TFs-ARDEGs and miRNA-ARDEGs regulatory network, miR-140-5p and Cebpb were predicted to be as crucial regulators in the progression of NP. For the ssGSEA results, Sirt2 was positively correlated with Eosinophil and Effector memory CD8⁺ T cell infiltration, which suggested that it may be involved in the regulation of neuroimmune-related signaling.

CONCLUSION

Two autophagy-related differentially expressed genes, especially Sirt2, may be potential biomarkers for NP, providing more evidence about the crucial role of autophagy in neuropathic pain.

Insights into Structural Modifications of Valproic Acid and Their Pharmacological Profile

Valproic acid (VPA) is a well-established anticonvulsant drug discovered serendipitously and marketed for the treatment of epilepsy, migraine, bipolar disorder and neuropathic pain. Apart from this, VPA has potential therapeutic applications in other central nervous system (CNS) disorders and in various cancer types. Since the discovery of its anticonvulsant activity, substantial efforts have been made to develop structural analogues and derivatives in an attempt to increase potency and decrease adverse side effects, the most significant being teratogenicity and hepatotoxicity. Most of these compounds have shown reduced toxicity with improved potency. The simple structure of VPA offers a great advantage to its modification. This review briefly discusses the pharmacology and molecular targets of VPA. The article then elaborates on the structural modifications in VPA including amide-derivatives, acid and cyclic analogues, urea derivatives and pro-drugs, and compares their pharmacological profile with that of the parent molecule. The current challenges for the clinical use of these derivatives are also discussed. The review is expected to provide necessary knowledgebase for the further development of VPA-derived compounds.

Design and evaluation of pharmacological properties of a new 1,3,4-thiadiazolylamide derivative of 2-propylpentanoic acid

Introduction: The use of the pharmacophoric approach is a promising direction for modifying the chemical structure of 2-propylpentanoic (valproic) acid in order to obtain new drugs.

Materials and methods: In the experiments on mice, acute toxicity, neurotoxicity, antiepileptic activity and analgesic effect of N-(5-ethyl-1,3,4-thiadiazol-2-yl)-2-propylpentanamide (valprazolamide) were evaluated. LD50 was determined by probit analysis. Neurotoxicity was determined in a rotarod test and a bar test in mice. The effects of valprazolamide on the exploratory behavior of mice in open field test and in a light/dark transition test were evaluated. Its antiepileptic activity was tested in mice against seizures induced by maximal electroshock, pentylenetetrazole (scPTZ); isoniazid, thiosemicarbazide, pilocarpine, and camphor. The analgesic effect was studied in a hot plate test.

Results and discussion: N-(5-ethyl-1,3,4-thiadiazol-2-yl)-2-propylpentanamide was obtained by introducing pharmacophores into the structure of 2-propylpentanoic acid: a substituted amide group and an electron-donor domain of 1,3,4-thiadiazole. The LD50 value for intraperitoneal administration of a new 2-propylpentanoic acid: derivative to mice was 924.8 mg/kg, and the TD50 value in the rotarod test and the bar test were 456.7 mg/kg and 546.7 mg/kg, respectively. The suppression of orienting responses in the animals was noted when it was administered in neurotoxic doses. Valprazolamide showed the most antiepileptic activity on models of MES, scPTZ and isoniazid antagonism tests. The ED50 values were 138.4 mg/kg, 74.5 mg/kg, and 126.8 mg/kg, respectively. The therapeutic indices for these models of epilepsy were 6.7; 12.4; 7.3, and protective index – 3.3; 6.1 and 3.6, respectively. In the hot plate test, valprazolamide increased the latency period before a defensive response to a thermal stimulus (ED50 165 mg/kg).

Conclusion: N-(5-ethyl-1,3,4-thiadiazol-2-yl)-2-propylpentanamide is a new 1,3,4-thiadiazolylamide derivative of 2-propylpentanoic acid with antiepileptic and analgesic activities, which belongs to the group of low-toxic agents.

Graphic abstract

N-(5-ethyl-1,3,4-thiadiazol-2-yl)-2-propylpentanamide (3D)

LD50=924.8 mg/kg (mice, intraperitoneally)

TD50=456.7 mg/kg (rotarod, mice, intraperitoneally)

ED50=138.4 mg/kg (MES, mice, intraperitoneally)

ED50=74.5 mg/kg (scPTZ, mice, intraperitoneally)

Synthesis, Anticonvulsant and Antinociceptive Activity of New Hybrid Compounds: Derivatives of 3-(3-Methylthiophen-2-yl)-pyrrolidine-2,5-dione

The present study aimed to design and synthesize a new series of hybrid compounds with pyrrolidine-2,5-dione and thiophene rings in the structure as potential anticonvulsant and antinociceptive agents. For this purpose, we obtained a series of new compounds and evaluated their anticonvulsant activity in animal models of epilepsy (maximal electroshock (MES), psychomotor (6 Hz), and subcutaneous pentylenetetrazole (scPTZ) seizure tests). To determine the mechanism of action of the most active anticonvulsant compounds (3, 4, 6, 9), their influence on the voltage-gated sodium and calcium channels as well as GABA transporter (GAT) was assessed. The most promising compound 3-(3-methylthiophen-2-yl)-1-(3-morpholinopropyl)pyrrolidine-2,5-dione hydrochloride (4) showed higher ED₅₀ value than those of the reference drugs: valproic acid (VPA) and ethosuximide (ETX) (62.14 mg/kg vs. 252.7 mg/kg (VPA) in the MES test, and 75.59 mg/kg vs. 130.6 mg/kg (VPA) and 221.7 mg/kg (ETX) in the 6 Hz test, respectively). Moreover, in vitro studies of compound 4 showed moderate but balanced inhibition of the neuronal voltage-sensitive sodium (site 2) and L-type calcium channels. Additionally, the antinociceptive activity of the most active compounds (3, 4, 6, 9) was also evaluated in the hot plate test and writhing tests, and their hepatotoxic properties in HepG2 cells were also investigated. To determine the possible mechanism of the analgesic effect of compounds 3, 6, and 9, the affinity for the TRPV1 receptor was investigated.

Novel treatment approaches and pediatric research networks in status epilepticus

This paper contains five contributions which were presented as part of the novel therapies section of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures. These illustrate recent advances being made in the management and therapy of status epilepticus. The five contributions concern: genetic variations in Na + channel genes and their importance in status epilepticus; the European Reference Network for rare and complex epilepsies EpiCARE; the North American Pediatric Status Epilepticus Research Group (pSERG); Fenfluramine as a potential therapy for status epilepticus' and the valproate derivatives, valnoctamide and sec-butylpropylacetamide (SPD), as potential therapies for status epilepticus. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".

Evaluation of anticonvulsant and analgesic activity of new hybrid compounds derived from N-phenyl-2-(2,5-dioxopyrrolidin-1-yl)-propanamides and -butanamides

Epilepsy is a chronic neurological disorder that is associated with various types of recurrent seizures, which are drug-resistant in about one third of patients. Moreover, anticonvulsant drugs are used to treat a wide range of non-epileptic conditions, including chronic pain. Here, we investigated the anticonvulsant activity of six new hybrid compounds based on the pyrrolidine-2,5-dione scaffold in the 6 Hz corneal stimulation test with 44 mA stimulus intensity in mice, which is the model of pharmacoresistant seizures. We demonstrated that two molecules, DK-10 (11) and DK-14 (14) show higher anticonvulsant activity and similar safety profile in comparison with valproic acid and much higher in comparison with levetiracetam in the aforementioned test. The second aim of this study was to examine analgesic activity of these compounds. For this purpose, the hot plate test, the formalin test, and the oxaliplatin-induced peripheral neuropathy model were performed. Among tested agents DK-11 (12) revealed prominent antinociceptive activity at non-sedative doses in the second (inflammatory) phase of the formalin test, which is the model of tonic pain and antiallodynic activity in the oxaliplatin-induced neuropathic pain, the model of painful chemotherapy-induced peripheral neuropathy. No cytotoxic effect on hepatoma cells was observed. Compound DK-10 (11) had high affinity for voltage-gated sodium channels, whereas compound DK-11 (12) showed weak binding toward sodium and calcium voltage-gated channels and the NMDA receptor. As a result, hybrid compounds reported herein seem to be very promising broad spectrum anticonvulsant molecules with collateral analgesic activity.

Diastereoselective Synthesis of Spirocyclopropanes under Mild Conditions via Formal [2 + 1] Cycloadditions Using 2,3-Dioxo-4-benzylidene-pyrrolidines

A highly diastereoselective cyclopropanation of cyclic enones with sulfur ylides was developed under catalyst-free conditions, producing multifunctional spirocyclopropanes in generally excellent yields (up to 99% yield and >99:1 d.r.). The asymmetric version of this method was realized by using an easily available chiral sulfur ylide, affording products with moderate to good stereoselectivity.

Analgesic, antiallodynic, and anticonvulsant activity of novel hybrid molecules derived from N-benzyl-2-(2,5-dioxopyrrolidin-1-yl)propanamide and 2-(2,5-dioxopyrrolidin-1-yl)butanamide in animal models of pain and epilepsy

The purpose of the present study was to examine the analgesic activity of six novel hybrid molecules, which demonstrated in the previous research anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole seizure (scPTZ) tests in mice. The antinociceptive properties were estimated in three models of pain in mice—the hot plate test, the formalin test, and in the oxaliplatin-induced neuropathy. Moreover, extended anticonvulsant studies were carried out and the antiseizure activity was investigated in the 6-Hz test. Considering drug safety evaluation, the influence of compounds on locomotor activity and contextual memory were checked. Furthermore, chosen molecules were tested in vitro for potential hepatotoxicity. To explain the probable mechanism of action, the radioligand binding assays were performed. In both phases of formalin test, analgesic activity demonstrated compounds 4, 8, and 9. These agents relieved also mechanical allodynia in oxaliplatin-induced model of neuropathic pain. At active doses, they did not influence locomotor activity of mice. Moreover, for compounds 8 and 9, no deleterious effect on memory was observed, but compound 4 might induce memory deficits. All tested compounds (4, 5, 8, 9, 15, and 16) inhibited psychomotor seizures with the ED₅₀ values = 24.66–47.21 mg/kg. The binding studies showed that compound 4 only at the high concentrations revealed the effective binding to the neuronal sodium channels and moderately binding to the L-type calcium (verapamil site) channels and NMDA receptors. The present preclinical results proved that novel hybrid molecules demonstrate very promising anticonvulsant and analgesic activity.