Possible Correlation between Cholinergic System Alterations and Neuro/Inflammation in Multiple Sclerosis

Delirium risk associated with Esketamine, Sevoflurane, Propofol, and Dexmedetomidine: A Real-World Study Based on the FDA Adverse Event Reporting System

OBJECTIVE

Delirium is a serious postoperative complication, increasingly recognized for its heightened risk following the use of sedative drugs. This study aimed to assess the relationship of esketamine, sevoflurane, propofol, and dexmedetomidine with the risk of delirium.

METHODS

Data were obtained from the FDA Adverse Event Reporting System (FAERS) database covering the period from the first quarter of 2004 to the second quarter of 2024. Cases of delirium associated with these medications were identified using preferred terms (PTs) defined by the Medical Dictionary for Regulatory Activities (MedDRA 20.0). Disproportionality analyses employed reported odds ratios (ROR) and multiple gamma-Poisson shrinkage (MGPS), while logistic regression assessed the effects of age and sex on the risk of delirium.

RESULTS

A total of 21,433,114 adverse events (AEs) were recorded in the FAERS database, including 16 cases of delirium associated with esketamine, 189 with propofol, 90 with sevoflurane, and 103 with dexmedetomidine. Propofol (ROR: 5.44, EBGM05: 4.8), sevoflurane (ROR: 9.9, EBGM05: 8.26), and dexmedetomidine (ROR: 21.1, EBGM05: 17.67) were significantly associated with the delirium risk, whereas esketamine (ROR: 1.45, EBGM05: 0.96) did not show a significant association. Age was identified as a significant risk factor for delirium, particularly in patients aged 55 years and older.

CONCLUSION

The findings indicate a significant correlation between propofol, sevoflurane, and dexmedetomidine and the risk of delirium, whereas esketamine does not appear to have a significant association with delirium. Future studies should further explore drug administration and dosage effects on delirium risk to improve clinical safety.

Unveiling the role of astrogliosis in Alzheimer's disease Pathology: Insights into mechanisms and therapeutic approaches

Alzheimer's disease (AD) is one of the most debilitating age-related disorders that affect people globally. It impacts social and cognitive behavior of the individual and is characterized by phosphorylated tau and Aβ accumulation. Astrocytesmaintain a quiescent, anti-inflammatory state on anatomical level, expressing few cytokines and exhibit phagocytic activity to remove misfolded proteins. But in AD, in response to specific stimuli, astrocytes overstimulate their phagocytic character with overexpressing cytokine gene modules. Upon interaction with generated Aβ and neurofibrillary tangle, astrocytes that are continuously activated release a large number of inflammatory cytokines. This cytokine storm leads to neuroinflammation which is also one of the recognizable features of AD. Astrogliosis eventually promotes cholinergic dysfunction, calcium imbalance, oxidative stress and excitotoxicity. Furthermore, C5aR1, Lcn2/, BDNF/TrkB and PPARα/TFEB signaling dysregulation has a major impact on the disease progression. This review clarifies numerous ways that lead to astrogliosis, which is stimulated by a variety of processes that exacerbate AD pathology and make it a suitable target for AD treatment. Drugs under clinical and preclinical investigations that target several pathways managing astrogliosis and are efficacious in ameliorating the pathology of the disease are also included in this study. D-ALA2GIP, TRAM-34, Genistein, L-serine, MW150 and XPro1595 are examples of few drugs targeting astrogliosis. Therefore, this study may aid in the development of a potent therapeutic agent for ameliorating astrogliosis mediated AD progression.

Herniarin ameliorates acrylamide-induced neurotoxicity in rat: involvement of neuro-inflammation and acetylcholinesterase

This study aimed to investigate the protective effects of herniarin against acrylamide neuro-toxicity. Rats were administered 50 mg/kg of acrylamide (Acr) along with oral doses of herniarin at 50, 100, and 200 mg/kg for 11 days. After treatment, the animals were sacrificed and biochemical markers including superoxide dismutase (SOD), catalase activity, malondialdehyde (MDA), nitric oxide (NO), thiols and acetylcholine esterase (AChE) level were evaluated. Moreover, mRNA expression of neuro-inflammatory cytokines including TNF-α, IL-1β, and IL-6 were measured using qRT-PCR method. As results, Acr increased MDA with subsequent reduction in SOD, catalase, and thiols content. In contrast, administration of herniarin remarkably normalised the antioxidants and decreased lipid peroxidation. Furthermore, it downregulated mRNA expression of TNF-α, IL-1β, and IL-6 (p < 0.001) as well as decreased NO (p < 0.01) and AchE levels (p < 0.001) in the Acr-injured brains. Herniarin ameliorated Acr-induced brain injury via modulating redox hemostasis, cholinergic function, as well as inhibiting neuro-inflammation in rats.

The role and mechanism of dapagliflozin in Alzheimer disease: A review

Alzheimer disease (AD), as the main type of dementia, is primarily characterized by cognitive dysfunction across multiple domains. Current drugs for AD have not achieved the desired clinical efficacy due to potential risks, inapplicability, high costs, significant side effects, and poor patient compliance. However, recent findings offer new hope by suggesting that sodium-glucose cotransporter 2 inhibitors (SGLT-2i) may possess neuroprotective properties, potentially opening up novel avenues for the treatment of AD. This review delves deeply into the multifaceted mechanisms of action of SGLT-2i in AD, encompassing antioxidative stress, antineuroinflammation, upregulation of autophagy, antiapoptosis, acetylcholinesterase inhibitor activity, and protection of endothelial cells against atherosclerosis and damage to the blood-brain barrier, among others. Furthermore, it provides an overview of recent advances in clinical research on this drug. These findings suggest that SGLT-2i is poised to emerge as a pivotal candidate for the treatment of AD, given its diverse functional effects.

Electrical stimulation of the vagus nerve ameliorates inflammation and disease activity in a rat EAE model of multiple sclerosis

Multiple sclerosis (MS) is a demyelinating central nervous system (CNS) disorder that is associated with functional impairment and accruing disability. There are multiple U.S. Food and Drug Administration (FDA)-approved drugs that effectively dampen inflammation and slow disability progression. However, these agents do not work well for all patients and are associated with side effects that may limit their use. The vagus nerve (VN) provides a direct communication conduit between the CNS and the periphery, and modulation of the inflammatory reflex via electrical stimulation of the VN (VNS) shows efficacy in ameliorating pathology in several CNS and autoimmune disorders. We therefore investigated the impact of VNS in a rat experimental autoimmune encephalomyelitis (EAE) model of MS. In this study, VNS-mediated neuroimmune modulation is demonstrated to effectively decrease EAE disease severity and duration, infiltration of neutrophils and pathogenic lymphocytes, myelin damage, blood-brain barrier disruption, fibrinogen deposition, and proinflammatory microglial activation. VNS modulates expression of genes that are implicated in MS pathogenesis, as well as those encoding myelin proteins and transcription factors regulating new myelin synthesis. Together, these data indicate that neuroimmune modulation via VNS may be a promising approach to treat MS, that not only ameliorates symptoms but potentially also promotes myelin repair (remyelination).

Muscarinic Receptors and Alzheimer's Disease: New Perspectives and Mechanisms

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases on a global scale. Historically, this pathology has been linked to cholinergic transmission, and despite the scarcity of effective therapies, numerous alternative processes and targets have been proposed as potential avenues for comprehending this complex illness. Nevertheless, the fundamental pathophysiological mechanisms underpinning AD remain largely enigmatic, with a growing body of evidence advocating for the significance of muscarinic receptors in modulating the brain's capacity to adapt and generate new memories. This review summarizes the current state of the art in the field of muscarinic receptors' involvement in AD. A specific key factor was the relationship between comorbidity and the emergence of new mechanisms.

Cedrol supplementation ameliorates memory deficits by regulating neuro-inflammation and cholinergic function in lipopolysaccharide-induced cognitive impairment in rats

BACKGROUND

Cedrol, a sesquiterpene alcohol, is found in a high amount in several conifers. It possess several beneficial health effects, including antioxidant and anti-inflammatory properties. Objective: This study evaluates the neuroprotective role of cedrol against lipopolysaccharide (LPS)-induced neuroinflammation and memory loss in rats.

METHODS

Wistar rats were treated with cedrol (7.5, 15, and 30 mg/kg, oral, two weeks). During the last week, the rats (except for the control group) were treated with LPS (intraperitoneal injection, 1 mg/kg) to induce memory impairment. After that, the animals were subjected to behavioral studies (Morris water maze and passive avoidance) and biochemical assessments.

RESULTS

Our results showed a significant decrease in learning and memory function-in LPS-induced rats which were reversed by cedrol. Also, there was a significant increase in the cerebral levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and malondialdehyde (MDA) as well as acetylcholinesterase (AChE) activity in LPS-treated rats. Besides, a significant reduction in total thiol and superoxide dismutase levels was observed in LPS-treated rats. However, cedrol significantly decreased the brain level of AChE, TNF-α, and IL-1β. Administration of cedrol also restored the oxidative stress markers.

CONCLUSION

the beneficial effects of cedrol against LPS-induced memory impairment could be due to antioxidant activities and modulation of neuro-inflammatory mediators.

Role of fenofibrate in multiple sclerosis

Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the central nervous system (CNS). The underlying pathophysiology of MS is the destruction of myelin sheath by immune cells. The formation of myelin plaques, inflammation, and injury of neuronal myelin sheath characterizes its neuropathology. MS plaques are multiple focal regions of demyelination disseminated in the brain's white matter, spinal cords, deep grey matter, and cerebral cortex. Fenofibrate is a peroxisome proliferative activated receptor alpha (PPAR-α) that attenuates the inflammatory reactions in MS. Fenofibrate inhibits differentiation of Th17 by inhibiting the expression of pro-inflammatory signaling. According to these findings, this review intended to illuminate the mechanistic immunoinflammatory role of fenofibrate in mitigating MS neuropathology. In conclusion, fenofibrate can attenuate MS neuropathology by modulating different pathways, including oxidative stress, autophagy, mitochondrial dysfunction, inflammatory-signaling pathways, and neuroinflammation.

Pathogenic Role of Fibrinogen in the Neuropathology of Multiple Sclerosis: A Tale of Sorrows and Fears

Multiple sclerosis (MS) is an autoimmune demyelinating neurodegenerative disease of the central nervous system (CNS) due to injury of the myelin sheath by immune cells. The clotting factor fibrinogen is involved in the pathogenesis of MS by triggering microglia and the progress of neuroinflammation. Fibrinogen level is correlated with MS severity; consequently, inhibition of the fibrinogen cascade may reduce MS neuropathology. Thus, this review aimed to clarify the potential role of fibrinogen in the pathogenesis of MS and how targeting of fibrinogen affects MS neuropathology. Accumulation of fibrinogen in the CNS may occur independently or due to disruption of blood-brain barrier (BBB) integrity in MS. Fibrinogen acts as transduction and increases microglia activation which induces the progression of inflammation, oxidative stress, and neuronal injury. Besides, brain fibrinogen impairs the remyelination process by inhibiting the differentiation of oligodendrocyte precursor cells. These findings proposed that fibrinogen is associated with MS neuropathology through interruption of BBB integrity, induction of neuroinflammation, and demyelination with inhibition of the remyelination process by suppressing oligodendrocytes. Therefore, targeting of fibrinogen and/or CD11b/CD18 receptors by metformin and statins might decrease MS neuropathology. In conclusion, inhibiting the expression of CD11b/CD18 receptors by metformin and statins may decrease the pro-inflammatory effect of fibrinogen on microglia which is involved in the progression of MS.

Nicotinic Acetylcholine Receptor Dysfunction in Addiction and in Some Neurodegenerative and Neuropsychiatric Diseases

The cholinergic system plays an essential role in brain development, physiology, and pathophysiology. Herein, we review how specific alterations in this system, through genetic mutations or abnormal receptor function, can lead to aberrant neural circuitry that triggers disease. The review focuses on the nicotinic acetylcholine receptor (nAChR) and its role in addiction and in neurodegenerative and neuropsychiatric diseases and epilepsy. Cholinergic dysfunction is associated with inflammatory processes mainly through the involvement of α7 nAChRs expressed in brain and in peripheral immune cells. Evidence suggests that these neuroinflammatory processes trigger and aggravate pathological states. We discuss the preclinical evidence demonstrating the therapeutic potential of nAChR ligands in Alzheimer disease, Parkinson disease, schizophrenia spectrum disorders, and in autosomal dominant sleep-related hypermotor epilepsy. PubMed and Google Scholar bibliographic databases were searched with the keywords indicated below.

Inflammatory Processes in Alzheimer's Disease-Pathomechanism, Diagnosis and Treatment: A Review

Alzheimer's disease is one of the most commonly diagnosed cases of senile dementia in the world. It is an incurable process, most often leading to death. This disease is multifactorial, and one factor of this is inflammation. Numerous mediators secreted by inflammatory cells can cause neuronal degeneration. Neuritis may coexist with other mechanisms of Alzheimer's disease, contributing to disease progression, and may also directly underlie AD. Although much has been established about the inflammatory processes in the pathogenesis of AD, many aspects remain unexplained. The work is devoted in particular to the pathomechanism of inflammation and its role in diagnosis and treatment. An in-depth and detailed understanding of the pathomechanism of neuroinflammation in Alzheimer's disease may help in the development of diagnostic methods for early diagnosis and may contribute to the development of new therapeutic strategies for the disease.

Dysregulation of butyrylcholinesterase, BCHE gene SNP rs1803274, and pro-inflammatory cytokines in occupational workers

BACKGROUND

People in different occupations are exposed to a variety of xenobiotics which affect the health and physiological processes of the body. Butyrylcholinesterase (BChE), has been reported to play neuronal and non-neuronal roles, though its exact function is yet to be established. This study aimed to find the status and role of BChE in seven different occupational groups; gasoline fillers, auto-mechanics, carpenters, textile shop workers, furniture shop workers, electricians, and office workers.

METHODS

A total of 400 samples were screened. BChE activity was determined by Worek et al. method based on Ellman's principle. Pro-inflammatory cytokines were determined by ELISA. Genotypic analysis of the K-variant of BCHE gene SNP was carried out by standard molecular methods. Among seven groups, office workers were taken as a control to compare the results with all other occupational groups.

RESULTS

The results revealed a significant decrease in BChE activity in gasoline fillers (79.52%) followed by carpenters (73.49%), auto mechanics (39.76%), textile shop workers (18.07%), electricians (10.84%), and furniture shop workers (7.23%). TNF-α, IL-6, and IL1-β were elevated in all groups. IL-6 and IL1-β in gasoline fillers, and electricians were not statistically significantly increased. Binomial regression to determine the odd ratio was found to be significant (p < 0.05) in all groups. However, correlation (Pearson) did not reveal significance between different biochemical parameters. Genotypic analysis of the K-variant SNP of the BCHE gene showed a significant association with occupational groups when compared with control which indicates a possible association with xenobiotics exposure and the physiological role of K-variant in understudied occupational groups.

CONCLUSION

The study concluded that BChE and its gene SNP rs 1803274 and proinflammatory cytokines significantly dysregulates under the exposure to cumulative multiple xenobiotics in different occupational groups which may lead to pathophysiological conditions.

Antigen B modulates anti-inflammatory cytokines in the EAE model of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is characterized by the destruction of the blood-brain barrier, loss of myelin sheath, and contribution of inflammatory interleukins such as TNF-alpha, interleukin-17, and interleukin-6.

METHODS

The current study investigated the effect of antigen B of hydatid cyst fluid on the reduction of anti-inflammatory cytokines and nerve conduction velocity in rats with experimental autoimmune encephalomyelitis (EAE)-induced MS. After isolation of antigen B from sterile cyst fluid, the rats were randomly divided into four groups: saline, EAE, EAE + teriflunomide (EAE + TF), and EAE + antigen B (EAE + AngB). The EAE model was induced using cow spinal cord homogenization, in combination with Freund's complete adjuvant. The serum concentration of cytokines including IL-1B and IL-17, IL-10, IL-6, and TNF-X was measured by the ELISA method, and real-time PCR was performed to study gene expression. Electrophysiological, behavioral, and neuropathological tests were also conducted.

RESULTS

Nerve conduction velocity and IL-10 concentration were increased in the antigen B group. The results of this study showed that antigen B reduced the inflammatory component of the EAE MS animal model by modulating the immune system compared to teriflunomide, which eventually led to a reduction in symptoms at the behavioral and electrophysiological level.

CONCLUSIONS

It seems that antigen B plays a critical role in regulating immunity and it can be used as a possible therapeutic agent to modulate the immune system in MS patients. It might be rational to consider hydatid cyst fluid antigen as a modifier in MS.

Emerging Roles of Cholinergic Receptors in Schwann Cell Development and Plasticity

The cross talk between neurons and glial cells during development, adulthood, and disease, has been extensively documented. Among the molecules mediating these interactions, neurotransmitters play a relevant role both in myelinating and non-myelinating glial cells, thus resulting as additional candidates regulating the development and physiology of the glial cells. In this review, we summarise the contribution of the main neurotransmitter receptors in the regulation of the morphogenetic events of glial cells, with particular attention paid to the role of acetylcholine receptors in Schwann cell physiology. In particular, the M2 muscarinic receptor influences Schwann cell phenotype and the α7 nicotinic receptor is emerging as influential in the modulation of peripheral nerve regeneration and inflammation. This new evidence significantly improves our knowledge of Schwann cell development and function and may contribute to identifying interesting new targets to support the activity of these cells in pathological conditions.

Minocycline attenuates cholinergic dysfunction and neuro-inflammation-mediated cognitive impairment in scopolamine-induced Alzheimer's rat model

OBJECTIVE

Minocycline, a semisynthetic tetracycline-derived antibiotic, has various pharmacological effect such as anti-inflammatory, anti-oxidative stress, and anti-apoptotic effects. The current study investigated the involvement of neuro-inflammatory, oxidative stress, and cholinergic markers in neuroprotection by minocycline against scopolamine-induced brain damage.

METHODS

Minocycline was administered (oral, 10, 15, and 30 mg/kg, daily) to groups of amnesic rats for 21 days. Passive avoidance memory and spatial learning and memory were assessed. Following that, oxidative stress, cholinergic function, and neuro-inflammation markers were evaluated in the brain tissue.

RESULTS

According to our biochemical data, treatment of the scopolamine-injured rats with minocycline decreased the levels of malondialdehyde and acetylcholinesterase (AChE) as well as mRNA expression of AChE and neuro-inflammation markers (tumor necrosis factor-α, interleukin (IL)-1β, IL-6). It also increased the total thiol levels and superoxide dismutase activity as well as mRNA expression of cholinergic receptor M1 (ChRM1). Moreover, minocycline modified distance and latencies in Morris water maze, prolonged latency to enter the black zone and light time while decreasing time spent and frequency of entries to darkness.

CONCLUSION

Taken together, the data indicate that treatment with minocycline improved memory dysfunction mediated possibly through restoring AChE and ChRM1 levels, oxidant/antioxidant balance, as well as inhibiting inflammatory responses.

Effects Mediated by Dimethyl Fumarate on In Vitro Oligodendrocytes: Implications in Multiple Sclerosis

Background: Dimethyl fumarate (DMF) is a drug currently in use in oral therapy for the treatment of relapsing-remitting multiple sclerosis (RRMS) due to its immunomodulatory and neuroprotective effects. The mechanisms by which DMF exerts its therapeutic effects in MS and in particular its influence on the oligodendrocytes (OLs) survival or differentiation have not yet been fully understood. Methods: Characterization of Oli neu cells was performed by immunocytochemistry and RT-PCR. The effect of DMF on cell proliferation and morphology was assessed by MTT assay, trypan blue staining, RT-PCR and Western blot analysis. The antioxidant and anti-inflammatory properties of DMF were analysed by ROS detection through DCFDA staining and lipid content analysis by Oil Red O staining and TLC. Results: DMF has been observed to induce a slowdown of cell proliferation, favoring the oligodendrocyte lineage cells (OLCs) differentiation. DMF has an antioxidant effect and is able to modify the lipid content even after the LPS-mediated inflammatory stimulus in Oli neu cells. Conclusions: The results obtained confirm that DMF has anti-inflammatory and antioxidant effects also on Oli neu cells. Interestingly, it appears to promote the OLCs differentiation towards mature and potentially myelinating cells.

Cholinergic immunomodulation in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are chronic intestinal disorders characterized by dysregulated immune responses to resident microbiota in genetically susceptible hosts. The activation of the cholinergic system has been proposed for the treatment of IBD patients according to its potential anti-inflammatory effect in vivo. The α-7-nicotinic-acetylcholine receptor (α7nAChR) is involved in the inhibition of inflammatory processes, modulating the production of cytokines, suppressing dendritic cells and macrophage activity, leading to the suppression of T cells. In this review, we address the most recent studies and clinical trials concerning cholinergic signaling and its therapeutic potential for inflammatory bowel diseases.

Role of the Cholinergic Anti-Inflammatory Reflex in Central Nervous System Diseases

In several central nervous system diseases, it has been reported that inflammation may be related to the etiologic process, therefore, therapeutic strategies are being implemented to control inflammation. As the nervous system and the immune system maintain close bidirectional communication in physiological and pathological conditions, the modulation of inflammation through the cholinergic anti-inflammatory reflex has been proposed. In this review, we summarized the evidence supporting chemical stimulation with cholinergic agonists and vagus nerve stimulation as therapeutic strategies in the treatment of various central nervous system pathologies, and their effect on inflammation.

Nucleus basalis of Meynert damage and cognition in patients with multiple sclerosis

BACKGROUND

The nucleus basalis of Meynert (NBM), representing the major source of cerebral cholinergic innervations, is vulnerable to neurodegeneration in Alzheimer's and Parkinson's disease.

OBJECTIVE

To determine associations between NBM properties and cognitive outcomes in patients with multiple sclerosis (PwMS).

METHODS

84 PwMS and 19 controls underwent 3T MRI, the Paced Auditory Serial Addition Test (PASAT) and subtests of the Brief International Cognitive Assessment for MS (BICAMS). NBM volume, fractional anisotropy, mean diffusivity (MD), axial diffusivity and radial diffusivity (D⊥) were calculated. Analyses assessed relationships between cognition and NBM measures. Linear regressions evaluated the prognostic value of baseline measures in predicting cognitive change over 3 years of follow-up (n = 67).

RESULTS

Cognitive tests correlated with NBM diffusivity in PwMS (range r = - 0.29 to r = - 0.40, p < 0.05). After accounting for NBM volume, NBM MD and D⊥ explained additional variance (adjusted R2 range 0.08-0.20, p < 0.05). Correlations between NBM imaging metrics and cognitive tests remained significant when including imaging parameters of other cognitive key brain regions in the models. After controlling for age, education, and baseline cognitive test score, NBM measures predicted change in cognition over follow-up in 5 of 10 and 2 of 10 assessments in the relapsing-remitting sample (n = 43) (adjusted R2 range from 0.23 to 0.38, p < 0.05) and secondary progressive sample (adjusted R2 of 0.280 and 0.183), respectively.

CONCLUSIONS

NBM damage is linked to cognitive impairment in PwMS.

Editorial of Special Issue "Multiple Sclerosis: Diagnosis and Treatment II"

The special issue on Multiple Sclerosis: Diagnosis and Treatment II, reflects advances and discoveries in the molecular and cellular mechanisms of disease, and novel laboratory techniques providing more sensitivity to diagnostic techninques and the understanding of neuroinflammation. Mitochondrial-mediated apoptosis in isolated peripheral blood mononuclear cells and the role of reactive oxygen species are studied as indicators of activity of MS. In these cells, downregulation of circular and linera RNAs are reported as markers of highly active disease in MS. Progress and importance of Neurofilaments determinations in early diagnosis and as a marker of disease activity, and the analysis of the complex mechanisms and therapeutic potential of Sphingosine-1-phosphate receptor modulator are discussed. Epidemiologic observations from a highly diversified area of the world provide more insights into this important aspect of MS; discussions on the clinical challenges posed by spinal cord involvement in demyelinatind disorders and the latest aspects of pediatric onset MS, complement this fine collection of scientific papers.

Neuroinflammation Modulation via α7 Nicotinic Acetylcholine Receptor and Its Chaperone, RIC-3

Nicotinic acetylcholine receptors (nAChRs) are widely expressed in or on various cell types and have diverse functions. In immune cells nAChRs regulate proliferation, differentiation and cytokine release. Specifically, activation of the α7 nAChR reduces inflammation as part of the cholinergic anti-inflammatory pathway. Here we review numerous effects of α7 nAChR activation on immune cell function and differentiation. Further, we also describe evidence implicating this receptor and its chaperone RIC-3 in diseases of the central nervous system and in neuroinflammation, focusing on multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Deregulated neuroinflammation due to dysfunction of α7 nAChR provides one explanation for involvement of this receptor and of RIC-3 in neurodegenerative diseases. In this review, we also provide evidence implicating α7 nAChRs and RIC-3 in neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) involving neuroinflammation. Besides, we will describe the therapeutic implications of activating the cholinergic anti-inflammatory pathway for diseases involving neuroinflammation.

Therapeutic Effect of Combining Anisodamine With Neostigmine on Local Scar Formation Following Roux-en-Y Choledochojejunostomy in a Novel Rat Model

Background: The present study aimed to explore the potential effect of combining anisodamine with neostigmine on local scar formation following Roux-en-Y choledochojejunostomy (RCJS) in a novel rat model. Methods: The biliary obstruction model of Sprague Dawley (SD) rats was established in advance, and 54 rats were divided into nine groups randomly (sham operation group, anisodamine group, neostigmine group, combination group, and control group). Anisodamine (25 mg/kg) and neostigmine (50 μg/kg) were injected to the abdominal cavity separately or simultaneously for 1 week since the first day after surgery according to their allocated intervention, while the same amount of saline (0.5 ml) was injected intraperitoneally in the control group. Indexes including body weight, the diameter of the common bile duct, liver function, inflammatory indexes, and the condition of scar formation in different groups at certain time were evaluated in our study. Results: Recovery of liver function (ALT, AST, TB, DB, and GGT) and systematic inflammation indexes (CRP, TNF-α, and IL-1β) in the combination group was prior to that in the control group (p < 0.05), while no statistical difference in the serum level of IL-10 was observed among groups. Rats in the combination group represented a wider anastomotic diameter and lower expression of α-SMA and TGF-β1 at anastomotic stoma compared to the control group (p < 0.05). Histopathological staining showed slighter proliferation of collagen and smooth muscle fibers in rats' bile duct wall and less local scar formation at anastomotic stoma compared to the control group. Conclusion: The combination of anisodamine and neostigmine can alleviate local and systemic inflammatory response, promote the recovery of liver function, and reduce scar formation in rats after the RCJS procedure.

Regulators of cholinergic signaling in disorders of the central nervous system

Cholinergic signaling is crucial in cognitive processes, and degenerating cholinergic projections are a pathological hallmark in dementia. Use of cholinesterase inhibitors is currently the main treatment option to alleviate symptoms of Alzheimer's disease and has been postulated as a therapeutic strategy in acute brain damage (stroke and traumatic brain injury). However, the benefits of this treatment are still not clear. Importantly, cholinergic receptors are expressed both by neurons and by astrocytes and microglia, and binding of acetylcholine to the α7 nicotinic receptor in glial cells results in anti-inflammatory response. Similarly, the brain fine-tunes the peripheral immune response over the cholinergic anti-inflammatory axis. All of these processes are of importance for the outcome of acute and chronic neurological disease. Here, we summarize the main findings about the role of cholinergic signaling in brain disorders and provide insights into the complexity of molecular regulators of cholinergic responses, such as microRNAs and transfer RNA fragments, both of which may fine-tune the orchestra of cholinergic mRNAs. The available data suggest that these small noncoding RNA regulators may include promising biomarkers for predicting disease course and assessing treatment responses and might also serve as drug targets to attenuate signaling cascades during overwhelming inflammation and to ameliorate regenerative capacities of neuroinflammation.

Acetylcholinesterase Inhibitors in the Treatment of Neurodegenerative Diseases and the Role of Acetylcholinesterase in their Pathogenesis

Acetylcholinesterase (AChE) plays an important role in the pathogenesis of neurodegenerative diseases by influencing the inflammatory response, apoptosis, oxidative stress and aggregation of pathological proteins. There is a search for new compounds that can prevent the occurrence of neurodegenerative diseases and slow down their course. The aim of this review is to present the role of AChE in the pathomechanism of neurodegenerative diseases. In addition, this review aims to reveal the benefits of using AChE inhibitors to treat these diseases. The selected new AChE inhibitors were also assessed in terms of their potential use in the described disease entities. Designing and searching for new drugs targeting AChE may in the future allow the discovery of therapies that will be effective in the treatment of neurodegenerative diseases.

Inflammatory neuropsychiatric disorders and COVID-19 neuroinflammation

Neuropsychiatric sequalae to coronavirus disease 2019 (COVID-19) infection are beginning to emerge, like previous Spanish influenza and severe acute respiratory syndrome episodes. Streptococcal infection in paediatric patients causing obsessive compulsive disorder (PANDAS) is another recent example of an infection-based psychiatric disorder. Inflammation associated with neuropsychiatric disorders has been previously reported but there is no standard clinical management approach established. Part of the reason is that it is unclear what factors determine the specific neuronal vulnerability and the efficacy of anti-inflammatory treatment in neuroinflammation. The emerging COVID-19 data suggested that in the acute stage, widespread neuronal damage appears to be the result of abnormal and overactive immune responses and cytokine storm is associated with poor prognosis. It is still too early to know if there are long-term-specific neuronal or brain regional damages associated with COVID-19, resulting in distinct neuropsychiatric disorders. In several major psychiatric disorders where neuroinflammation is present, patients with abnormal inflammatory markers may also experience less than favourable response or treatment resistance when standard treatment is used alone. Evidence regarding the benefits of co-administered anti-inflammatory agents such as COX-2 inhibitor is encouraging in selected patients though may not benefit others. Disease-modifying therapies are increasingly being applied to neuropsychiatric diseases characterised by abnormal or hyperreactive immune responses. Adjunct anti-inflammatory treatment may benefit selected patients and is definitely an important component of clinical management in the presence of neuroinflammation.

Breast cancer: Muscarinic receptors as new targets for tumor therapy

The development of breast cancer is a complex process that involves the participation of different factors. Several authors have demonstrated the overexpression of muscarinic acetylcholine receptors (mAChRs) in different tumor tissues and their role in the modulation of tumor biology, positioning them as therapeutic targets in cancer. The conventional treatment for breast cancer involves surgery, radiotherapy, and/or chemotherapy. The latter presents disadvantages such as limited specificity, the appearance of resistance to treatment and other side effects. To prevent these side effects, several schedules of drug administration, like metronomic therapy, have been developed. Metronomic therapy is a type of chemotherapy in which one or more drugs are administered at low concentrations repetitively. Recently, two chemotherapeutic agents usually used to treat breast cancer have been considered able to activate mAChRs. The combination of low concentrations of these chemotherapeutic agents with muscarinic agonists could be a useful option to be applied in breast cancer treatment, since this combination not only reduces tumor cell survival without affecting normal cells, but also decreases pathological neo-angiogenesis, the expression of drug extrusion proteins and the cancer stem cell fraction. In this review, we focus on the previous evidences that have positioned mAChRs as relevant therapeutic targets in breast cancer and analyze the effects of administering muscarinic agonists in combination with conventional chemotherapeutic agents in a metronomic schedule.

Cardiac Autonomic Dysfunction in Myasthenia Gravis and Relapsing-Remitting Multiple Sclerosis-A Pilot Study

This study assessed cardiac autonomic response to head-up tilt test (HUTT) in 23 myasthenia gravis (MG) and 23 relapsing-remitting multiple sclerosis (RRMS) patients compared to 30 healthy controls (HC). Task Force® Monitor was used to evaluate cardiac inotropy parameters, baroreflex sensitivity (BRS), heart rate (HRV), and blood pressure variability (BPV) during HUTT. MG patients were characterized by reduced BRS (p < 0.05), post-HUTT decrease in high-frequency component (p < 0.05) and increase in sympathovagal ratio of HRV (p < 0.05) when compared to controls indicating parasympathetic deficiency with a shift of sympathovagal balance toward sympathetic predominance. Compared to HC, MG patients also showed lower cardiac inotropy parameters, specifically, left ventricular work index (LVWI) during supine rest (p < 0.05) as well as LVWI and cardiac index values in response to orthostatic stress (p < 0.01 and p < 0.05, respectively). Compared to controls, RRMS patients were characterized by lower HRV delta power spectral density (p < 0.05) and delta low-frequency HRV (p < 0.05) in response to HUTT suggesting combined sympathetic and parasympathetic dysfunction. There were no differences in cardiac autonomic parameters between MG and MS patients (p > 0.05). Our study highlights the possibility of cardiac and autonomic dysfunction in patients with MG and RRMS which should be considered in the pharmacological and rehabilitation approach to managing these conditions.

Cholinergic Modulation of Neuroinflammation: Focus on α7 Nicotinic Receptor

All nervous system pathologies (e.g., neurodegenerative/demyelinating diseases and brain tumours) develop neuroinflammation, a beneficial process during pathological events, aimed at removing damaged cells, toxic agents, and/or pathogens. Unfortunately, excessive inflammation frequently occurs during nervous system disorders, becoming a detrimental event capable of enhancing neurons and myelinating glial cell impairment, rather than improving their survival and activity. Consequently, targeting the neuroinflammation could be relevant for reducing brain injury and rescuing neuronal and glial cell functions. Several studies have highlighted the role of acetylcholine and its receptors in the regulation of central and peripheral inflammation. In particular, α7 nicotinic receptor has been described as one of the main regulators of the “brain cholinergic anti-inflammatory pathway”. Its expression in astrocytes and microglial cells and the ability to modulate anti-inflammatory cytokines make this receptor a new interesting therapeutic target for neuroinflammation regulation. In this review, we summarize the distribution and physiological functions of the α7 nicotinic receptor in glial cells (astrocytes and microglia) and its role in the modulation of neuroinflammation. Moreover, we explore how its altered expression and function contribute to the development of different neurological pathologies and exacerbate neuroinflammatory processes.

Suppression of neuroinflammation by an allosteric agonist and positive allosteric modulator of the α7 nicotinic acetylcholine receptor GAT107

Background

The α7 nicotinic acetylcholine receptor (α7 nAChR) negatively regulates the synthesis and release of pro-inflammatory cytokines by immune cells. Our previous studies showed that in encephalitogenic T cells, α7 nAChR expression is upregulated and that activation of the cholinergic system can attenuate experimental autoimmune encephalomyelitis (EAE). GAT107 is an allosteric agonist and positive allosteric modulator (ago-PAM) of α7 nAChR that can produce persistent activation of this receptor. Therefore, in the present study, we investigated the effect of GAT107 on neuroinflammation in EAE, the animal model used for the study of multiple sclerosis (MS) via α7 nAChR, and the inflammatory pathways involved.

Methods

EAE was induced by administration of myelin oligodendrocyte glycoprotein (MOG_35–55) in C57BL/6 mice. EAE mice were treated with the ago-PAM GAT107 or a placebo for 9 days, starting from the day of EAE induction. Clinical assessment and immunological evaluation of immune cells and cytokine production was performed.

Results

Following activation of the α7 nAChR by GAT107 during EAE, disease severity was significantly reduced by 70% and was correlated with a reduction in the extent of neuroinflammation in the CNS. The treatment reduced encephalitogenic T cell proliferation and the production of pro-inflammatory cytokines, as well as increased the production of the anti-inflammatory cytokine IL-10. Furthermore, the expression of immune cell markers was altered by GAT107 treatment, which induced a significant reduction in macrophages, dendritic cells, and B cells, as well as a reduction in anti-MOG_35–55 antibodies. Additionally, GAT107 was found to directly activate α7 nAChR in murine macrophage RAW264.7 cells and in human PBMCs derived from MS patients and healthy donors.

Conclusions

Our results show that GAT107 can be a useful molecule for harnessing the cholinergic anti-inflammatory pathway for long-lasting and wide-ranging modulation and downregulation of neuroinflammation in EAE.

Cholinergic Modulation of the Immune System in Neuroinflammatory Diseases

Frequent diseases of the CNS, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and psychiatric disorders (e.g., schizophrenia), elicit a neuroinflammatory response that contributes to the neurodegenerative disease process itself. The immune and nervous systems use the same mediators, receptors, and cells to regulate the immune and nervous systems as well as neuro-immune interactions. In various neurodegenerative diseases, peripheral inflammatory mediators and infiltrating immune cells from the periphery cause exacerbation to current injury in the brain. Acetylcholine (ACh) plays a crucial role in the peripheral and central nervous systems, in fact, other than cells of the CNS, the peripheral immune cells also possess a cholinergic system. The findings on peripheral cholinergic signaling, and the activation of the “cholinergic anti-inflammatory pathway” mediated by ACh binding to α7 nAChR as one of the possible mechanisms for controlling inflammation, have restarted interest in cholinergic-mediated pathological processes and in the new potential therapeutic target for neuro-inflammatory-degenerative diseases. Herein, we focus on recent progress in the modulatory mechanisms of the cholinergic anti-inflammatory pathway in neuroinflammatory diseases.

The Combination of the M2 Muscarinic Receptor Agonist and Chemotherapy Affects Drug Resistance in Neuroblastoma Cells

One of the major limits of chemotherapy is depending on the ability of the cancer cells to elude and adapt to different drugs. Recently, we demonstrated how the activation of the M2 muscarinic receptor could impair neuroblastoma cell proliferation. In the present paper, we investigate the possible effects mediated by the preferential M2 receptor agonist arecaidine propargyl ester (APE) on drug resistance in two neuroblastoma cell lines, SK-N-BE and SK-N-BE(2C), a sub-clone presenting drug resistance. In both cell lines, we compare the expression of the M2 receptor and the effects mediated by the M2 agonist APE on cell cycle, demonstrating a decreased percentage of cells in S phase and an accumulation of SK-N-BE cells in G1 phase, while the APE treatment of SK-N-BE(2C) cells induced a block in G2/M phase. The withdrawal of the M2 agonist from the medium shows that only the SK-N-BE(2C) cells are able to rescue cell proliferation. Further, we demonstrate that the co-treatment of low doses of APE with doxorubicin or cisplatin significantly counteracts cell proliferation when compared with the single treatment. Analysis of the expression of ATP-binding cassette (ABC) efflux pumps demonstrates the ability of the M2 agonist to downregulate their expression and that this negative modulation may be dependent on N-MYC decreased expression induced by the M2 agonist. Our data demonstrate that the combined effect of low doses of conventional drugs and the M2 agonist may represent a new promising therapeutic approach in neuroblastoma treatment, in light of its significant impact on drug resistance and the possible reduction in the side effects caused by high doses of chemotherapy drugs.