Evaluation of dextromethorphan with select antidepressant therapy for the treatment of depression in the acute care psychiatric setting

Introduction

Dextromethorphan (DXM), an N-methyl-D-aspartate receptor antagonist, may have ketamine-like antidepressant effects. Dextromethorphan is extensively metabolized via cytochrome P450 (CYP) 2D6, and its half-life in extensive metabolizers is 2 to 4 hours. The purpose of this study was to evaluate the effects of DXM in combination with a moderate-to-strong CYP2D6 inhibitor antidepressant on depression in an acute care psychiatric setting.

Methods

This was a single-center, retrospective chart review of adult patients with a depressive disorder diagnosis. Patients who received select antidepressant therapy with or without scheduled DXM were included. The primary outcome was the difference in time to improvement of depressive symptoms, which was an average composite of physician documentation, nurse documentation, and first time to 24 hours without as-needed anxiolytics or antipsychotics. The study group consisted of patients who received DXM with select antidepressant therapy, whereas the control group included those who received only select antidepressant therapy.

Results

A total of 40 patients were included. The median time to clinical improvement was 3.00 days and 2.83 days for the study group and control group, respectively (P = .986). The incidence of perceptual disturbances and delusions was higher in the study group as compared with the control group (55% and 35% vs 30% and 25%, respectively).

Discussion

Dextromethorphan was not associated with a rapid antidepressant effect. The commonly used dose of 30 mg daily may have been too low to have an effect; additionally, the most frequently utilized select antidepressant, bupropion, has moderately less CYP2D6 inhibition than fluoxetine and paroxetine.

Monomethyl Fumarate Protects the Retina From Light-Induced Retinopathy

Purpose

We determine if monomethyl fumarate (MMF) can protect the retina in mice subjected to light-induced retinopathy (LIR).

Methods

Albino BALB/c mice were intraperitoneally injected with 50 to 100 mg/kg MMF before or after exposure to bright white light (10,000 lux) for 1 hour. Seven days after light exposure, retinal structure and function were evaluated by optical coherence tomography (OCT) and electroretinography (ERG), respectively. Retinal histology also was performed to evaluate photoreceptor loss. Expression levels of Hcar2 and markers of microglia activation were measured by quantitative PCR (qPCR) in the neural retina with and without microglia depletion. At 24 hours after light exposure, retinal sections and whole mount retinas were stained with Iba1 to evaluate microglia status. The effect of MMF on the nuclear factor kB subunit 1 (NF-kB) and Nrf2 pathways was measured by qPCR and Western blot.

Results

MMF administered before light exposure mediated dose-dependent neuroprotection in a mouse model of LIR. A single dose of 100 mg/kg MMF fully protected retinal structure and function without side effects. Expression of the Hcar2 receptor and the microglia marker Cd14 were upregulated by LIR, but suppressed by MMF. Depleting microglia reduced Hcar2 expression and its upregulation by LIR. Microglial activation, upregulation of proinflammatory genes (Nlrp3, Caspase1, Il-1β, Tnf-α), and upregulation of antioxidative stress genes (Hmox1) associated with LIR were mitigated by MMF treatment.

Conclusions

MMF can completely protect the retina from LIR in BALB/c mice. Expression of Hcar2, the receptor of MMF, is microglia-dependent in the neural retina. MMF-mediated neuroprotection was associated with attenuation of microglia activation, inflammation and oxidative stress in the retina.

Intra-arterial administration of cell-based biological agents for ischemic stroke therapy

INTRODUCTION

Ischemic stroke is becoming a primary cause of disability and death worldwide. To date, therapeutic options remain limited focusing on mechanical thrombolysis or administration of thrombolytic agents. However, these therapies do not promote neuroprotection and neuro-restoration of the ischemic area of the brain.

AREAS COVERED

This review highlights the option of minimal invasive, intra-arterial, administration of biological agents for stroke therapy. The authors provide an update of all available studies, discuss issues that influence outcomes and describe future perspectives which aim to improve clinical outcomes. New therapeutic options based on cellular and molecular interactions following an ischemic brain event, will be highlighted.

EXPERT OPINION

Intra-arterial administration of biological agents during trans-catheter thrombolysis or thrombectomy could limit neuronal cell death and facilitate regeneration or neurogenesis following ischemic brain injury. Despite the initial progress, further meticulous studies are needed in order to establish the clinical use of stem cell-induced neuroprotection and neuroregeneration.

Liraglutide alleviates cardiac fibrosis through inhibiting P4hα-1 expression in STZ-induced diabetic cardiomyopathy

Diabetic cardiomyopathy is an important contributor to morbidity and mortality of diabetic patients by causing heart failure. Interstitial and perivascular fibrosis plays a crucial role in diabetic cardiomyopathy. However, there is a lack of effective specific treatments available for diabetic cardiomyopathy. In the present study, we aim to explore the effects of Liraglutide, a GLP-1 analogue, on diabetic cardiomyopathy in STZ-induced diabetic rats fed with high-fat diet. A total of 60 male Wistar rats were randomly assigned to three groups, i.e. normal group, model group, and Liraglutide group, with 20 rats in each group. Serum levels of TC, TG, LDL-C, NEFA, and hydroxyproline were measured using commercial kits. Cardiac function was evaluated by QRS waves, LVEDd, LVESd, and LVEF. Myocardial fibrosis was measured by immunohistochemistry. Our results demonstrated that chronic administration of Liraglutide decreased the level of blood glucose and significantly alleviated lipid metabolic disturbance compared with the model group. Furthermore, Liraglutide was found to improve the damaged cardiac function. In line with this, we also found that the alleviation of cardiac dysfunction was associated with the decreased fibrosis in diabetic myocardial tissues, which was reflected by the decreased expressions of P4hα-1, COL-1, COL-3, MMP-1, and MMP-9. Our results thus suggest that Liraglutide might have a myocardial protective effect by inhibiting P4hα-1-mediated myocardial fibrosis.

Microarray gene expression profiling and bioinformatics analysis reveal key differentially expressed genes in clival and sacral chordoma cell lines

OBJECTIVE

Chordoma is a rare tumor with a certain rate of distant metastasis. Skull base and sacrum are the two most common origin sites. This study tends to identify key differentially expressed genes (DEGs) between classical clival and sacral chordomas, provide new targets for future treatment options of chordomas.

METHODS

The gene expression profiles of GSE95084 and GSE68497 were downloaded from Gene Expression Omnibus database and were analyzed using the limma R package. Function and enrichment analyses of DEGs were performed based on DAVID Database. Protein-protein interaction (PPI) network was constructed using the Cytoscape based on the data collected from STRING online datasets. Hub genes selection and modules analyses of the PPI network were conducted by plugin cytoHubba and MCODE of Cytoscape software, respectively.

RESULT

In total, 728 genes, including 363 up-regulated genes and 365 down-regulated genes were selected as DEGs. Notably, GO analysis showed that both up-regulated and down-regulated DEGs were mainly involved in cell component such as an integral component of the membrane, plasma membrane and extracellular exosome. DEGs were mainly enriched in pathways like Pathways in cancer, PI3K-Akt signaling pathway, Cytokine-cytokine receptor interaction. FYN, ITGB3, ACTN2 and IGF1 were identified as hub genes and they were all involved in focal adhesion signaling pathway. Furthermore, five significant network modules were obtained from the PPI network.

CONCLUSION

This study helps to further understand the molecular characteristics of classic chordomas of two distinct sites. Hub genes FYN, ITGB3, ACTN2, and IGF1, as well as focal adhesion signaling pathway, would be new targets for future treatment options of chordomas.

Correlations between Body Mass Index, Plasma High-Sensitivity C-Reactive Protein and Lipids in Patients with Schizophrenia

High prevalence of obesity in individuals with schizophrenia, associated with metabolic syndrome, leads to high rate of premature deaths from cardiovascular disease (CVD) in this population. Body mass index (BMI) and C-reactive protein (CRP) are correlated in the general population but this relationship has not been fully elucidated in patients with schizophrenia. We aimed to evaluate the correlation between BMI and CRP while relating both variables to plasma lipids in patients with schizophrenia. BMI, fasting high sensitivity CRP (hs-CRP), cotinine, and lipids were measured in 106 patients with schizophrenia (diagnosis confirmed with MINI). Pearson's and partial correlations (adjusting for age, sex, race, education and cotinine) between BMI, hs-CRP and lipids were calculated. Based on BMI, the patients were divided into normal-weight vs. overweight/obese and t-tests and linear regression were done to compare hs-CRP and lipids in the 2 groups. BMI positively correlated with hs-CRP (r = 0.29, p = 0.004). BMI and hs-CRP negatively correlated with HDL in the total sample (r = -0.29, p = 0.004; r = -0.37, p < 0.001 respectively). Furthermore, hs-CRP negatively correlated with HDL in overweight/obese patients (r = -0.41, p = 0.003), but not in normal-weight patients. hs-CRP and triglycerides were higher (1.62 ± 0.09 mg/L vs. 0.56 ± 0.08 mg/L, p < 0.001; 121.77 ± 8.96 mg/dL vs. 91.23 ± 6.52 mg/dL, p = 0.008 respectively) and HDL lower (39.55 ± 1.48 mg/dL vs. 50.68 ± 2.24 mg/dL, p < 0.001) in overweight/obese patients. Being overweight/obese is associated with increased inflammation and dyslipidemia in patients with schizophrenia. Effective interventions to prevent weight gain in schizophrenia are urgently needed.

Kisspeptin Stimulation of Prolactin Secretion Requires Kiss1 Receptor but Not in Tuberoinfundibular Dopaminergic Neurons

Kisspeptin has been shown to stimulate prolactin secretion. We investigated whether kisspeptin acts through the Kiss1 receptor (Kiss1r) to regulate dopamine and prolactin. Initially, we evaluated prolactin response in a Kiss1r-deficient mouse line, in which Kiss1r had been knocked into GnRH neurons (Kiss1r-/-R). Intracerebroventricular kisspeptin-10 (Kp-10) increased prolactin release in wild-type but not in Kiss1r-/-R female mice. In ovariectomized, estradiol-treated rats, the Kiss1r antagonist kisspeptin-234 abolished the Kp-10-induced increase in prolactin release but failed to prevent the concomitant reduction in the activity of tuberoinfundibular dopaminergic (TIDA) neurons, as determined by the 3,4-dihydroxyphenylacetic acid/dopamine ratio in the median eminence. Using whole-cell patch clamp recordings in juvenile male rats, we found no direct effect of Kp-10 on the electrical activity of TIDA neurons. In addition, dual-label in situ hybridization in the hypothalamus of female rats showed that Kiss1r is expressed in the periventricular nucleus of the hypothalamus (Pe) and arcuate nucleus of the hypothalamus (ARC) but not in tyrosine hydroxylase (Th)-expressing neurons. Kisspeptin also has affinity for the neuropeptide FF receptor 1 (Npffr1), which was expressed in the majority of Pe dopaminergic neurons but only in a low proportion of TIDA neurons in the ARC. Our findings demonstrate that Kiss1r is necessary to the effect of kisspeptin on prolactin secretion, although TIDA neurons lack Kiss1r and are electrically unresponsive to kisspeptin. Thus, kisspeptin is likely to stimulate prolactin secretion via Kiss1r in nondopaminergic neurons, whereas the colocalization of Npffr1 and Th suggests that Pe dopaminergic neurons may play a role in the kisspeptin-induced inhibition of dopamine release.

Neuroprotective Actions of Glucagon-Like Peptide-1 (GLP-1) Analogues in Alzheimer's and Parkinson's Diseases

The current absence of effective treatments for Alzheimer's disease (AD) and Parkinson's disease (PD) reflects an incomplete knowledge of the underlying disease processes. Considerable efforts have been made to investigate the central pathological features of these diseases, giving rise to numerous attempts to develop compounds that interfere with such features. However, further characterization of the molecular targets within the interconnected AD and PD pathways is still required. Impaired brain insulin signaling has emerged as a feature that contributes to neuronal dysfunction in both AD and PD, leading to strategies aiming at restoring this pathway in the brain. Long-acting glucagon-like peptide-1 (GLP-1) analogues marketed for treatment of type 2 diabetes mellitus have been tested and have shown encouraging protective actions in experimental models of AD and PD as well as in initial clinical trials. We review studies revealing the neuroprotective actions of GLP-1 analogues in pre-clinical models of AD and PD and promising results from recent clinical trials.

Towards feedback-controlled nanomedicines for smart, adaptive delivery

IMPACT STATEMENT

The timing and rate of release of pharmaceuticals from advanced drug delivery systems is an important property that has received considerable attention in the scientific literature. Broadly, these mostly fall into two classes: controlled release with a prolonged release rate or triggered release where the drug is rapidly released in response to an environmental stimulus. This review aims to highlight the potential for developing adaptive release systems that more subtlety modulate the drug release profile through continuous communication with its environment facilitated through feedback control. By reviewing the key elements of this approach in one place (fundamental principles of nanomedicine, enzymatic nanoreactors for medical therapies and feedback-controlled chemical systems) and providing additional motivating case studies in the context of chronobiology, we hope to inspire innovative development of novel "chrononanomedicines."

Peptidylarginine deiminase and deiminated proteins are detected throughout early halibut ontogeny - Complement components C3 and C4 are post-translationally deiminated in halibut (Hippoglossus hippoglossus L.)

Post-translational protein deimination is mediated by peptidylarginine deiminases (PADs), which are calcium dependent enzymes conserved throughout phylogeny with physiological and pathophysiological roles. Protein deimination occurs via the conversion of protein arginine into citrulline, leading to structural and functional changes in target proteins. In a continuous series of early halibut development from 37 to 1050° d, PAD, total deiminated proteins and deiminated histone H3 showed variation in temporal and spatial detection in various organs including yolksac, muscle, skin, liver, brain, eye, spinal cord, chondrocytes, heart, intestines, kidney and pancreas throughout early ontogeny. For the first time in any species, deimination of complement components C3 and C4 is shown in halibut serum, indicating a novel mechanism of complement regulation in immune responses and homeostasis. Proteomic analysis of deiminated target proteins in halibut serum further identified complement components C5, C7, C8 C9 and C1 inhibitor, as well as various other immunogenic, metabolic, cytoskeletal and nuclear proteins. Post-translational deimination may facilitate protein moonlighting, an evolutionary conserved phenomenon, allowing one polypeptide chain to carry out various functions to meet functional requirements for diverse roles in immune defences and tissue remodelling.

IL-12, IL-23 and IL-17 in IBD: immunobiology and therapeutic targeting

IL-12 and IL-23 are closely related cytokines with important roles in the regulation of tissue inflammation. Converging evidence from studies in mice, human observational studies and population genetics supports the importance of these cytokines in the regulation of mucosal inflammation in the gut in particular. Ustekinumab, a therapeutic antibody targeting both cytokines is now widely licensed for the treatment of Crohn's disease, including in Europe, the USA, Canada and Japan, whilst agents targeting IL-23 specifically are in late-phase clinical trials. We review the emerging understanding of the biology of IL-12 and IL-23, as well as that of their major downstream cytokines, including IL-17. In particular, we discuss how their biology has influenced the development of clinical trials and therapeutic strategies in IBD, as well as how findings from clinical trials, at times surprising, have in turn refocused our understanding of the underlying biology.

Sympathetic nervous system in age-related cardiovascular dysfunction: Pathophysiology and therapeutic perspective

Cardiovascular diseases such as heart failure and metabolic syndrome have high prevalence in the elderly population and are leading causes of death, disability, hospitalization, driving high healthcare costs worldwide. To reduce this social and economic burden there is urgency to find effective therapeutic targets. Several studies have linked the dysfunction of the Sympathetic Nervous System and β-adrenergic receptor signaling with the pathogenesis of age-related cardiovascular diseases. Therapeutic treatments that restore their functions have been shown to be effective in subjects with cardiovascular comorbidities. In fact, lifestyle interventions (such as exercise training and diet) as well as pharmacologic treatments (e.g. β-blockers or moxonidine) and mini-invasive interventions (renal sympathetic denervation) have beneficial effects on age-related cardiovascular diseases. In the current "Medicine in focus" article we will discuss the pathogenic role of the Sympathetic Nervous System in age-related cardiovascular diseases as well as current and new therapeutic approaches.

Role of Notch Signaling Pathway in Glioblastoma Pathogenesis

Notch signaling is an evolutionarily conserved pathway that regulates important biological processes, such as cell proliferation, apoptosis, migration, self-renewal, and differentiation. In mammals, Notch signaling is composed of four receptors (Notch1–4) and five ligands (Dll1-3–4, Jagged1–2) that mainly contribute to the development and maintenance of the central nervous system (CNS). Neural stem cells (NSCs) are the starting point for neurogenesis and other neurological functions, representing an essential aspect for the homeostasis of the CNS. Therefore, genetic and functional alterations to NSCs can lead to the development of brain tumors, including glioblastoma. Glioblastoma remains an incurable disease, and the reason for the failure of current therapies and tumor relapse is the presence of a small subpopulation of tumor cells known as glioma stem cells (GSCs), characterized by their stem cell-like properties and aggressive phenotype. Growing evidence reveals that Notch signaling is highly active in GSCs, where it suppresses differentiation and maintains stem-like properties, contributing to Glioblastoma tumorigenesis and conventional-treatment resistance. In this review, we try to give a comprehensive view of the contribution of Notch signaling to Glioblastoma and its possible implication as a target for new therapeutic approaches.

Glycosylation profiling of dog serum reveals differences compared to human serum

Glycosylation is the most common post-translational modification of serum proteins, and changes in the type and abundance of glycans in human serum have been correlated with a growing number of human diseases. While the glycosylation pattern of human serum is well studied, little is known about the profiles of other mammalian species. Here, we report detailed glycosylation profiling of canine serum by hydrophilic interaction chromatography-ultraperformance liquid chromatography (HILIC-UPLC) and mass spectrometry. The domestic dog (Canis familiaris) is a widely used model organism and of considerable interest for a large veterinary community. We found significant differences in the serum N-glycosylation profile of dogs compared to that of humans, such as a lower abundance of galactosylated and sialylated glycans. We also compare the N-glycan profile of canine serum to that of canine IgG – the most abundant serum glycoprotein. Our data will serve as a baseline reference for future studies when performing serum analyses of various health and disease states in dogs.

Targeting the crosstalks of Wnt pathway with Hedgehog and Notch for cancer therapy

Wnt pathway is an evolutionarily conserved signaling pathway determining patterning of animal embryos, cell fate, cell polarity, and a substantial role in the origin and maintenance of stem cells. It has been found to crosstalk with two other major developmental pathways, Hedgehog and Notch, in many embryological development cascades and in maintaining stemness of stem cells Research has shown that all the three pathways are potent in inducing tumorigenesis, driving tumor progression and aiding epithelial to mesenchymal transition in malignant cells, apart from maintaining cancer stem cells population inside the tumor tissue. Cancer stem cells are thought to aid in the process of tumor relapse, as they survive therapy by displaying drug resistance and then repopulating tumor tissues. Hence the role of these crosstalks in cancer is under intensive research. Inhibition of all the three pathways individually have resulted in tumor regression, but not optimally, as treatment failure and cancer relapse have been found to occur. Hence, instead of targeting a single pathway, targeting the crosstalk network could be a better alternative to conventional cancer treatment. Also, elimination of both tumor cells as well as cancer stem cells implies a reduced chance of relapse. Drugs developed to target these crosstalking networks, when used in combinatorial therapy, can potentially increase the efficacy of the therapy to a very large extent.

Dyk S, Malan SF. Hexacyclododecylamines with Sigma-1 Receptor Affinity and Calcium Channel Modulating Ability

Introduction:

Recent research points to the Sigma Receptor (σR) as a possible neuromodulatory system with multi-functional action and σ1Rs have been suggested as a drug target for a number of CNS conditions. Hexacyclododecylamines have shown σ1R activity and provide an advantageous scaffold for drug design that can improve the blood-brain barrier permeability of privileged structures.

Methods and Materials:

A series of oxa- and aza- hexaxcyclododecylamines were synthesised and evaluated for sigma-1 receptor activity and voltage-gated calcium channel blocking ability to determine the effect of inclusion of amine containing heterocycles.

Results & Discussion:

The compounds had promising σ1R activities (Ki = 0.067 – 11.86 µM) with the aza-hexacyclododecylamines 12, 24 and 27 showing some of the highest affinities (Ki = 0.067 µM, 0.215 µM and 0.496 µM respectively). This confirms, as observed in previous studies, that the aza compounds are more favourable for σ1R binding than their oxa counterparts. The addition of the amine heterocycle showed affinities similar to that of related structures with only two lipophilic binding regions. This indicates that the inclusion of an amine heterocycle into these structures is a viable option in the design of new σ1R ligands. Significant voltage-gated calcium channel blocking ability was also observed for 12, 24 and 27, suggesting a link between σ1R activity and intracellular calcium levels.

Conclusion:

The σ1R activity and potential effect on other receptor classes and calcium channels could prove beneficial in pharmacological application.

Evaluation of 12 GWAS-drawn SNPs as biomarkers of rheumatoid arthritis response to TNF inhibitors. A potential SNP association with response to etanercept

Research in rheumatoid arthritis (RA) is increasingly focused on the discovery of biomarkers that could enable personalized treatments. The genetic biomarkers associated with the response to TNF inhibitors (TNFi) are among the most studied. They include 12 SNPs exhibiting promising results in the three largest genome-wide association studies (GWAS). However, they still require further validation. With this aim, we assessed their association with response to TNFi in a replication study, and a meta-analysis summarizing all non-redundant data. The replication involved 755 patients with RA that were treated for the first time with a biologic drug, which was either infliximab (n = 397), etanercept (n = 155) or adalimumab (n = 203). Their DNA samples were successfully genotyped with a single-base extension multiplex method. Lamentably, none of the 12 SNPs was associated with response to the TNFi in the replication study (p > 0.05). However, a drug-stratified exploratory analysis revealed a significant association of the NUBPL rs2378945 SNP with a poor response to etanercept (B = -0.50, 95% CI = -0.82, -0.17, p = 0.003). In addition, the meta-analysis reinforced the previous association of three SNPs: rs2378945, rs12142623, and rs4651370. In contrast, five of the remaining SNPs were less associated than before, and the other four SNPs were no longer associated with the response to treatment. In summary, our results highlight the complexity of the pharmacogenetics of TNFi in RA showing that it could involve a drug-specific component and clarifying the status of the 12 GWAS-drawn SNPs.

Comparison of null models for combination drug therapy reveals Hand model as biochemically most plausible

Null models for the effect of combination therapies are widely used to evaluate synergy and antagonism of drugs. Due to the relevance of null models, their suitability is continuously discussed. Here, we contribute to the discussion by investigating the properties of five null models. Our study includes the model proposed by David J. Hand, which we refer to as Hand model. The Hand model has been introduced almost 20 years ago but hardly was used and studied. We show that the Hand model generalizes the principle of dose equivalence compared to the Loewe model and resolves the ambiguity of the Tallarida model. This provides a solution to the persisting conflict about the compatibility of two essential model properties: the sham combination principle and the principle of dose equivalence. By embedding several null models into a common framework, we shed light in their biochemical validity and provide indications that the Hand model is biochemically most plausible. We illustrate the practical implications and differences between null models by examining differences of null models on published data.

Targeting Mechanosensitive Transcription Factors in Atherosclerosis

Atherosclerosis is the primary underlying cause of cardiovascular disease which preferentially develops at arterial regions exposed to disturbed flow (DF), but much less at regions of unidirectional laminar flow (UF). Recent studies have demonstrated that DF and UF differentially regulate important aspects of endothelial function, such as vascular inflammation, oxidative stress, vascular tone, cell proliferation, senescence, mitochondrial function, and glucose metabolism. DF and UF regulate vascular pathophysiology via differential regulation of mechanosensitive transcription factors (MSTFs) (KLF2, KLF4, NRF2, YAP/TAZ/TEAD, HIF-1α, NF-κB, AP-1, and others). Emerging studies show that MSTFs represent promising therapeutic targets for the prevention and treatment of atherosclerosis. We present here a comprehensive overview of the role of MSTFs in atherosclerosis, and highlight future directions for developing novel therapeutic agents by targeting MSTFs.

Effects of antiarrhythmics on the electrical restitution in perfused guinea-pig heart are critically determined by the applied cardiac pacing protocol

NEW FINDINGS

What is the central question of this study? Are modifications in the restitution of ventricular action potential duration induced by antiarrhythmic drugs the same when assessed with premature extrastimulus application at variable coupling intervals (the standard stimulation protocol) and with steady state pacing at variable rates (the dynamic stimulation protocol)? What is the main finding and its importance? With class I and class III antiarrhythmics, the effects on electrical restitution determined with the standard stimulation protocol dissociate from those obtained during dynamic pacing. These findings indicate a limited value of the electrical restitution assessments based on extrasystolic stimulations alone, as performed in the clinical studies, in estimating the outcomes of antiarrhythmic drug therapies.

ABSTRACT

A steep slope of the ventricular action potential duration (APD) to diastolic interval (DI) relationships (the electrical restitution) can precipitate tachyarrhythmia, whereas a flattened slope is antiarrhythmic. The derangements in APD restitution responsible for transition of tachycardia to ventricular fibrillation can be assessed with cardiac pacing at progressively increasing rates (the dynamic stimulation protocol). Nevertheless, this method is not used clinically owing to the risk of inducing myocardial ischaemia. Instead, the restitution kinetics is determined with a premature extrastimulus application at variable coupling intervals (the standard stimulation protocol). Whether the two protocols are equivalent in estimating antiarrhythmic drug effects is uncertain. In this study, dofetilide and quinidine, the agents blocking repolarizing K⁺ currents, increased epicardial APD in perfused guinea-pig hearts, with effects being greater at long vs. short DIs. These changes were more pronounced during dynamic pacing compared to premature extrastimulations. Accordingly, although both agents markedly steepened the dynamic restitution, there was only a marginal increase in the standard restitution slope with dofetilide, and no effect with quinidine. Lidocaine and mexiletine, selective Na⁺ channel blockers, prolonged the effective refractory period without changing APD, and increased the minimum DI that enabled ventricular capture during extrastimulations. No change in the minimum DI was noted during dynamic pacing. Consequently, although lidocaine and mexiletine reduced the standard restitution slope, they failed to flatten the dynamic restitution. Overall, these findings imply a limited value of the electrical restitution assessments with premature extrastimulations alone in discriminating arrhythmic vs. antiarrhythmic changes during drug therapies.

Microglial Phagocytosis of Newborn Cells Is Induced by Endocannabinoids and Sculpts Sex Differences in Juvenile Rat Social Play

Brain sex differences are established developmentally and generate enduring changes in circuitry and behavior. Steroid-mediated masculinization of the rat amygdala during perinatal development produces higher levels of juvenile rough-and-tumble play by males. This sex difference in social play is highly conserved across mammals, yet the mechanisms by which it is established are unknown. Here, we report that androgen-induced increases in endocannabinoid tone promote microglia phagocytosis during a critical period of amygdala development. Phagocytic microglia engulf more viable newborn cells in males; in females, less phagocytosis allows more astrocytes to survive to the juvenile age. Blocking complement-dependent phagocytosis in males increases astrocyte survival and prevents masculinization of play. Moreover, increased astrocyte density in the juvenile amygdala reduces neuronal excitation during play. These findings highlight novel mechanisms of brain development whereby endocannabinoids induce microglia phagocytosis to regulate newborn astrocyte number and shape the sexual differentiation of social circuitry and behavior. VIDEO ABSTRACT.

Modulation of autophagy in human diseases strategies to foster strengths and circumvent weaknesses

Autophagy is central to the maintenance of intracellular homeostasis across species. Accordingly, autophagy disorders are linked to a variety of diseases from the embryonic stage until death, and the role of autophagy as a therapeutic target has been widely recognized. However, autophagy-associated therapy for human diseases is still in its infancy and is supported by limited evidence. In this review, we summarize the landscape of autophagy-associated diseases and current autophagy modulators. Furthermore, we investigate the existing autophagy-associated clinical trials, analyze the obstacles that limit their progress, offer tactics that may allow barriers to be overcome along the way and then discuss the therapeutic potential of autophagy modulators in clinical applications.

Overcoming the Blood–Brain Barrier. Challenges and Tricks for CNS Drug Delivery

Treatment of certain central nervous system disorders, including different types of cerebral malignancies, is limited by traditional oral or systemic administrations of therapeutic drugs due to possible serious side effects and/or lack of the brain penetration and, therefore, the efficacy of the drugs is diminished. During the last decade, several new technologies were developed to overcome barrier properties of cerebral capillaries. This review gives a short overview of the structural elements and anatomical features of the blood–brain barrier. The various in vitro (static and dynamic), in vivo (microdialysis), and in situ (brain perfusion) blood–brain barrier models are also presented. The drug formulations and administration options to deliver molecules effectively to the central nervous system (CNS) are presented. Nanocarriers, nanoparticles (lipid, polymeric, magnetic, gold, and carbon based nanoparticles, dendrimers, etc.), viral and peptid vectors and shuttles, sonoporation and microbubbles are briefly shown. The modulation of receptors and efflux transporters in the cell membrane can also be an effective approach to enhance brain exposure to therapeutic compounds. Intranasal administration is a noninvasive delivery route to bypass the blood–brain barrier, while direct brain administration is an invasive mode to target the brain region with therapeutic drug concentrations locally. Nowadays, both technological and mechanistic tools are available to assist in overcoming the blood–brain barrier. With these techniques more effective and even safer drugs can be developed for the treatment of devastating brain disorders.

Ketamine-induced antidepressant like effects in mice: A possible involvement of cannabinoid system

The purpose of this study was to explore the possible interaction between ketamine and cannabinoid system in the modulation of depression-related responses using the forced swimming test (FST), tail suspension test (TST) and open-field test (OFT) in mice. Our results revealed that intra-peritoneal (i.p.) injection of ketamine (5 and 10 mg/kg), a non-competitive NMDA antagonist, dose-dependently produced antidepressant-like effect in the FST. Moreover, i.p. administration of both CB1 and CB2 receptor drugs: ACPA (1 mg/kg; CB1 receptor agonist), AM251 (1 mg/kg; CB1 receptor antagonist), GP1a (2 mg/kg; CB2 receptor agonist) and AM630 (0.5 mg/kg; CB2 receptor antagonist) exhibited antidepressant action. Interestingly, the concomitant administration of ineffective doses of ketamine and cannabinoid receptor antagonists provoked the antidepressant-like effects as compared to control group. It should be considered, all above mentioned doses of drugs could not change locomotor activity in the OFT. It seems that possible interaction between ketamine and cannabinoid system may modulate depression-related behavior.

Nano curcumin supplementation reduced the severity of diabetic sensorimotor polyneuropathy in patients with type 2 diabetes mellitus: A randomized double-blind placebo- controlled clinical trial

BACKGROUND

Diabetic Sensorimotor Polyneuropathy (DSPN) is a common complication of diabetes mellitus. Curcumin is the most important ingredient found in turmeric which has a very high potential for eliminating free radicals and inhibiting oxidative stress as an antioxidant agent. The aim of this study was to determine the effect of Nano-curcumin supplementation on the severity of sensorimotor polyneuropathy in patients with Type 2 diabetes mellitus (T2DM).

METHOD

This parallel, double-blind randomized, placebo-controlled clinical trial was conducted on 80 diabetic patients. Participants were allocated randomly to the intervention (n = 40) and the control group (n = 40). They received 80 mg of nano-curcumin or placebo capsules for 8 weeks. Anthropometric measurements, dietary intake, physical activity, glycemic indices and the severity of DSPN were measured before and after the intervention.

RESULT

Supplementation of nano curcumin was accounted for a significant reduction in Glycated hemoglobin(HbA1c) (p < 0.001) and Fast Blood Sugar(FBS) (p = 0.004), total score of neuropathy (p < 0.001), total reflex score (p = 0.04) and temperature (p = 0.01) compared to placebo group.

CONCLUSION

Our findings indicated that curcumin supplementation for 2 months improved and reduced the severity of DSPN in patients with T2DM.

Protein Kinase C in the Cerebellum: Its Significance and Remaining Conundrums

Protein kinase C (PKC), a family of serine/threonine protein kinases, mediates a myriad of patho-physiological cellular events in various tissues. The originally discovered PKC (conventional) requires the binding of diacylglycerol and Ca²⁺ for full activation. The conventional PKC consists of four isoforms, PKCα, PKCβI/βII, and PKCγ. PKCα and PKCβI/βII are expressed in the cells of various tissues including the brain, while PKCγ is present specifically in neurons of the brain and spinal cord. The cerebellum expresses the largest amount of PKC with all its four isoforms. Purkinje cells express PKCα and PKCγ. Previous studies have shown that PKCα is involved in the induction of long-term depression (LTD) at parallel fiber-Purkinje cell synapses. On the other hand, analysis of PKCγ-deficient mice has revealed that PKCγ plays a critical role in eliminating supernumerary climbing fiber synapses from developing Purkinje cells. Although why PKCα has no compensatory action in climbing fiber pruning in PKCγ-deficient Purkinje cells had so far remained unclear, we have recently demonstrated that PKCα is also capable of pruning supernumerary climbing fiber synapses, but the expression levels of PKCα are too low to achieve pruning in PKCγ-null Purkinje cells. Notably, although PKCγ is most abundant in Purkinje cells, its physiological role in mature Purkinje cells remained totally unknown. In addition to a concise review of the physiological and pathological roles of conventional PKCs in Purkinje cells, this report postulates a contribution of PKCα in developing Purkinje cells and a possible involvement of PKCγ in motor coordination in the mature cerebellum.

Dose-Dependent Tissue Distribution of K117, a Bis-pyridinium Aldoxime, in Rats

Background:

Bis-pyridinium aldoximes are reactivators of the paraoxon-inhibited butyrylcholinesterase enzyme. Paraoxon is the active product of parathion, a widely used insecticide.

Objective:

The objective of this study is to examine the dose-dependent distribution of K117, a bis-pyridinium aldoxime in rat tissues.

Materials and Methods:

White male Wistar rats were intramuscularly injected with various doses of K117; the animals were sacrificed 30 minutes after injections. The dose-dependent body distribution of K117 was determined using reversed-phase HPLC.

Results:

Dose-dependent distribution of K117 in body tissues was linear in the serum and other body tissues throughout the whole range of the concentrations studied. However, the of distribution was not observed in the brain and cerebrospinal fluid, especially with high doses.

Conclusion:

The body distribution of K117 significantly depends on doses used, the p-value is: 500 nmol, i.m., when applied in the range of 100 to 10,000 nmol.

Cortistatin binds to TNF-α receptors and protects against osteoarthritis

Background

Osteoarthritis (OA) is a common degenerative disease, and tumor necrosis factor (TNF-α) is known to play a critical role in OA. Cortistatin (CST) is a neuropeptide discovered over 20  years ago, which plays a vital role in inflammatory reactions. However, it is unknown whether CST is involved in cartilage degeneration and OA development.

Methods

The interaction between CST and TNF-α receptors was investigated through Coimmunoprecipitation and Biotin-based solid-phase binding assay. Western blot, Real-time PCR, ELISA, immunofluorescence staining, nitrite production assay and DMMB assay of GAG were performed for the primary chondrocyte experiments. Surgically induced and spontaneous OA models were established and western blot, flow cytometry, Real-time PCR, ELISA, immunohistochemistry and fluorescence in vivo imaging were performed for in vivo experiments.

Findings

CST competitively bound to TNFR1 as well as TNFR2. CST suppressed proinflammatory function of TNF-α. Both spontaneous and surgically induced OA models indicated that deficiency of CST led to an accelerated OA-like phenotype, while exogenous CST attenuated OA development in vivo. Additionally, TNFR1- and TNFR2-knockout mice were used for analysis and indicated that TNFRs might be involved in the protective role of CST in OA. CST inhibited activation of the NF-κB signaling pathway in OA.

Interpretation

This study provides new insight into the pathogenesis and therapeutic strategy of cartilage degenerative diseases, including OA.

Fund

The National Natural Science Foundation of China, the Natural Science Foundation of Shandong Province, Key Research and Development Projects of Shandong Province and the Cross-disciplinary Fund of Shandong University.

Comparative solution and structural studies of half-sandwich rhodium and ruthenium complexes bearing curcumin and acetylacetone

Half-sandwich organometallic complexes of curcumin are extensively investigated as anticancer compounds. Speciation studies were performed to explore the solution stability of curcumin complexes formed with [Rh(η⁵-C₅Me₅)(H₂O)₃]²⁺. Acetylacetone (Hacac), as the simplest β-diketone ligand bearing (O,O) donor set, was involved for comparison and its Ru(η⁶‑p‑cymene), Ru(η⁶‑toluene) complexes were also studied. ¹H NMR, UV-visible and pH-potentiometric titrations revealed a clear trend of stability constants of the acac complexes: Ru(η⁶‑p‑cymene) > Ru(η⁶‑toluene) > Rh(η⁵-C₅Me₅). Despite this order, the highest extent of complex formation is seen for the Rh(η⁵-C₅Me₅) complexes at pH 7.4. Formation constant of [Rh(η⁵-C₅Me₅)(H₂curcumin)(H₂O)]⁺ reveals similar solution stability to that of the acac complex. Additionally, structures of two complexes were determined by X-ray crystallography. The in vitro cytotoxicity of curcumin was not improved by the complexation with these organometallic cations.

Coenzyme Q10 Alleviated Behavioral Dysfunction and Bioenergetic Function in an Animal Model of Depression

Coenzyme Q₁₀ (CoQ₁₀) is a natural compound, is involved in the mitochondrial electron transfer chain (ETC) and plays an important pattern in adenosine triphosphate (ATP) production. Amelioration of ATP is related to abnormalities in cognitive function and psychiatric diseases. Previous studies have shown that depression is accompanied by the induction of inflammatory and oxidative stress pathways and amelioration of antioxidant status. In a recent study, we investigated the beneficial effects of CoQ₁₀ on behavioral dysfunction and CoQ₁₀ level in the rat brain. Therefore, intracerebroventricular (ICV) infusion of a single dose of streptozotocin (STZ, 0.2 mg/mouse) was used in adult male mice to induce depression. The behavioral data revealed a significant difference between the depression and control groups regarding the forced swim test (FST) and splash test results at 24 h following STZ treatment. Also, the validated and accurate high-performance liquid chromatography (HPLC) technique showed decreased CoQ₁₀ level in the brain samples of the STZ group, compared to the controls. Our findings revealed that behavioral abnormalities due to STZ target mitochondria and affect energy metabolism and hemostasis, resulting in the initiation of oxidative damage in the brain. Besides, 4-week administration of CoQ₁₀ could reverse the depressive like behavior and bioenergetic effects of STZ in the treated groups.

Treatment with maresin 1, a docosahexaenoic acid-derived pro-resolution lipid, protects skin from inflammation and oxidative stress caused by UVB irradiation

Acute exposure to UVB irradiation causes skin inflammation and oxidative stress, and long-term exposure to UVB irradiation may lead to carcinogenesis. Our organism has endogenous mechanisms to actively limit inflammation. Maresin 1 (MaR1; 7R,14S-dihydroxy-docosa-4Z,8E,10E,12Z,16Z,19Z-hexaenoic acid) is a pro-resolution lipid mediator derived from the docosahexaenoic acid, which presents anti-inflammatory and pro-resolution effects. However, it remains to be determined if treatment with MaR1 can inhibit inflammatory and oxidative alterations in the skin triggered by UVB. The treatment with MaR1 (0.1-10 ng/mice at -10 min relative to the UVB irradiation protocol) reduced UVB-induced skin edema, neutrophil recruitment (MPO; myeloperoxidase activity, and migration of LysM-eGFP⁺ cells), cytokine production, matrix metalloproteinase-9 activity, keratinocyte apoptosis, epidermal thickening, mast cells counts and degradation of skin collagen in hairless mice. UVB irradiation caused a decrease of GSH (reduced glutathione) levels, activity of the enzyme catalase, ferric reducing ability (FRAP), and ABTS radical scavenging capacity as well as induced lipid hydroperoxide, superoxide anion production, and gp91^phox mRNA expression. These parameters that indicate oxidative stress were inhibited by MaR1 treatment. Therefore, these data suggest MaR1 as a promising pharmacological tool in controlling the deleterious effects related to UVB irradiation.

Botulinum neurotoxin serotype D - A potential treatment alternative for BoNT/A and B non-responding patients

OBJECTIVES

Botulinum neurotoxin serotypes A and B (BoNT/A & B) are highly effective medicines to treat hyperactive cholinergic neurons. Due to neutralizing antibody formation, some patients may become non-responders. In these cases, the serotypes BoNT/C-G might become treatment alternatives. BoNT/D is genetically least related to BoNT/A & B and thereby circumventing neutralisation in A/B non-responders. We produced BoNT/D and compared its pharmacology with BoNT/A ex vivo in mice tissue and in vivo in human volunteers.

METHODS

BoNT/D was expressed recombinantly in E. coli, isolated by chromatography and its ex vivo potency was determined at mouse phrenic nerve hemidiaphragm preparations. Different doses of BoNT/D or incobotulinumtoxinA were injected into the extensor digitorum brevis (EDB) muscles (n = 30) of human volunteers. Their compound muscle action potentials were measured 11 times by electroneurography within 220 days.

RESULTS

Despite a 3.7-fold lower ex vivo potency in mice, a 110-fold higher dosage of BoNT/D achieved the same clinical effect as incobotulinumtoxinA while showing a 50% shortened duration of action.

CONCLUSIONS

BoNT/D blocks dose-dependently acetylcholine release in human motoneurons upon intramuscular administration, but its potency and duration of action is inferior to approved BoNT/A based drugs.

SIGNIFICANCE

BoNT/D constitutes a potential treatment alternative for BoNT/A & B non-responders.

Role of Dehydrocorybulbine in Neuropathic Pain After Spinal Cord Injury Mediated by P2X4 Receptor

Chronic neuropathic pain is one of the primary causes of disability subsequent to spinal cord injury. Patients experiencing neuropathic pain after spinal cord injury suffer from poor quality of life, so complementary therapy is seriously needed. Dehydrocorybulbine is an alkaloid extracted from Corydalis yanhusuo. It effectively alleviates neuropathic pain. In the present study, we explored the effect of dehydrocorybulbine on neuropathic pain after spinal cord injury and delineated its possible mechanism. Experiments were performed in rats to evaluate the contribution of dehydrocorybulbine to P2X4 signaling in the modulation of pain-related behaviors and the levels of pronociceptive interleukins and proteins after spinal cord injury. In a rat contusion injury model, we confirmed that chronic neuropathic pain is present on day 7 after spinal cord injury and P2X4R expression is exacerbated after spinal cord injury. We also found that administration of dehydrocorybulbine by tail vein injection relieved pain behaviors in rat contusion injury models without affecting motor functions. The elevation in the levels of pronociceptive interleukins (IL-1β, IL-18, MMP-9) after spinal cord injury was mitigated by dehydrocorybulbine. Dehydrocorybulbine significantly mitigated the upregulation of P2X4 receptor and reduced ATP-evoked intracellular Ca2+ concentration. Both P2XR and dopamine receptor2 agonists antagonized dehydrocorybulbine's antinociceptive effects. In conclusion, we propose that dehydrocorybulbine produces antinociceptive effects in spinal cord injury models by inhibiting P2X4R.

A Novel TNF-α-Targeting Aptamer for TNF-α-Mediated Acute Lung Injury and Acute Liver Failure

Rationale: The TNF-α pathway plays as a double-edged sword that simultaneously regulates cell apoptosis and proliferation. The dysregulated TNF-α signaling can trigger cytokine storms that lead to profound cell death during the phase of acute tissue injury. On the other hand, an optimal level of TNF-α signaling is required for tissue repair following the acute injury phase. The TNF-α pathway is commonly upregulated in acute lung injury (ALI) and acute liver failure (ALF). Previous studies investigated the feasibility of adopting protein-based TNF-α blockers as disease modifiers in ALI and ALF, but none of these came out with a positive result. One of the potential reasons that resides behind the failure of the trials might be the long half-life of these inhibitors that led to undesired side effects. Developing alternative TNF-α blockers with manageable half-lives remain an unmet need in this regard.

Methods: In the current study, we developed a novel TNF-α-targeting aptamer (aptTNF-α) and its PEG-derivate (aptTNF-α-PEG) with antagonistic functions. We investigated the in vivo antagonistic effects using mouse ALI and ALF models.

Results: Our data showed that aptTNF-α possessed good in vitro binding affinity towards human/mouse TNF-α and successfully targeted TNF-α in vivo. In the mouse ALI model, aptTNF-α/aptTNF-α-PEG treatment attenuated the severity of LPS-induced ALI, as indicated by the improvement of oxygen saturation and lung injury scores, the reduction of protein-rich fluid leakage and neutrophil infiltration in the alveolar spaces, and the suppression of pro-inflammatory cytokines/chemokines expressions in the lung tissues. In the mouse ALF model, we further showed that aptTNF-α/aptTNF-α-PEG treatment not only attenuated the degree of hepatocyte damage upon acute injury but also potentiated early regeneration of the liver tissues.

Conclusion: The results implicated potential roles of aptTNF-α/aptTNF-α-PEG in ALI and ALF. The data also suggested their translational potential as a new category of TNF-α blocking agent.

Berberine Protects Glomerular Podocytes via Inhibiting Drp1-Mediated Mitochondrial Fission and Dysfunction

Elevated levels of plasma free fatty acid (FFA) and disturbed mitochondrial dynamics play crucial roles in the pathogenesis of diabetic kidney disease (DKD). However, the mechanisms by which FFA leads to mitochondrial damage in glomerular podocytes of DKD and the effects of Berberine (BBR) on podocytes are not fully understood.

Methods: Using the db/db diabetic mice model and cultured mouse podocytes, we investigated the molecular mechanism of FFA-induced disturbance of mitochondrial dynamics in podocytes and testified the effects of BBR on regulating mitochondrial dysfunction, podocyte apoptosis and glomerulopathy in the progression of DKD.

Results: Intragastric administration of BBR for 8 weeks in db/db mice significantly reversed glucose and lipid metabolism disorders, podocyte damage, basement membrane thickening, mesangial expansion and glomerulosclerosis. BBR strongly inhibited podocyte apoptosis, increased reactive oxygen species (ROS) generation, mitochondrial fragmentation and dysfunction both in vivo and in vitro. Mechanistically, BBR could stabilize mitochondrial morphology in podocytes via abolishing palmitic acid (PA)-induced activation of dynamin-related protein 1 (Drp1).

Conclusions: Our study demonstrated for the first time that BBR may have a previously unrecognized role in protecting glomerulus and podocytes via positively regulating Drp1-mediated mitochondrial dynamics. It might serve as a novel therapeutic drug for the treatment of DKD.

EZH2 plays a crucial role in ischemia/reperfusion-induced acute kidney injury by regulating p38 signaling

OBJECTIVE AND DESIGN

Renal ischemia-reperfusion (IR)-induced acute kidney injury (AKI) remains a major challenge in clinic. The histone methyltransferases enhancer of zest homolog-2 (EZH2) is associated with the development of renal injury. However, the molecular mechanism has not been fully elucidated.

MATERIALS

AKI in C57BL/6 mice was generated by renal IR.

TREATMENTS

The 3-deazaneplanocin A (DZNeP), a selective EZH2 inhibitor, or vehicle was administrated in mice after IR. HK-2 cells were exposed to hypoxia-reoxygenation (H/R) stress.

METHODS

Apoptosis was detected by TUNEL assay or flow cytometry. EZH2, caspase-3, p38, F4/80⁺ macrophages, and CD3⁺ T cells were examined by immunohistochemistry or Western blot. Tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, IL-6, and IL-18 were measured using RT-PCR.

RESULTS

Mice treated with DZNeP exhibited less severe renal dysfunction and tubular injury following IR. EZH2 inhibition decreased apoptotic cells while reducing activation of caspase-3 in kidneys under IR condition. Moreover, EZH2 inhibition impaired the recruitment of CD3⁺ T cells and F4/80⁺ cells in kidneys with IR. Administration of DZNeP suppressed the production of TNF-α, MCP-1, IL-6, and IL-18 in IR-treated kidneys. Of note, EZH2 inhibition reduced p38 phosphorylation in kidneys after IR. In H/R-treated HK-2 cells, DZNeP treatment or EZH2 knockdown reduced apoptosis. EZH2 inhibition inactivated p38 resulting in reduction of active caspase-3 and proinflammatory molecules. By contrast, EZH2 overexpression induced p38 phosphorylation, caspase-3 activation, and production of proinflammatory molecules, which was reversed by SB203580.

CONCLUSIONS

EZH2 plays a crucial role in IR-induced AKI via modulation of p38 signaling. Targeting EZH2/p38 signaling pathway may offer novel strategies to protect kidneys from acute kidney injury induced by ischemia-reperfusion.