Activation of Mast Cells by Neuropeptides: The Role of Pro-Inflammatory and Anti-Inflammatory Cytokines

The Role of Neuro-Immune Interactions in the Pathology and Pathogenesis of Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is a non-infectious inflammatory disease of the nasal mucosa mediated by IgE and involving a variety of immune cells such as mast cells. In previous studies, AR was considered as an isolated disease of the immune system. However, recent studies have found that the nervous system is closely related to the development of AR. Bidirectional communication between the nervous and immune systems plays an important role in AR.

SUMMARY

The nervous system and immune system depend on the anatomical relationship between nerve fibers and immune cells, as well as various neurotransmitters, cytokines, inflammatory mediators, etc. to produce bidirectional connections, which affect the development of AR.

KEY MESSAGES

This article reviews the impact of neuro-immune interactions in AR on the development of AR, including neuro-immune cell units.

IL-37 evaluation in chronic periodontitis after periodontal treatment with and without low level laser therapy

BACKGROUND

Periodontal disease poses a significant global health challenge. Traditional treatments focus on reducing inflammation and bacterial load, yet novel approaches are continually being investigated. Recent research suggests that IL-37, a potent anti-inflammatory cytokine, may play a crucial role in modulating the inflammatory processes associated with periodontal disease. In conjunction with IL-37, low-level laser therapy (LLLT) has gained attention for its potential in promoting tissue repair, reducing inflammation, and enhancing cellular processes. This study aims to investigate the effects of LLLT on IL-37 in periodontal disease management.

METHODS

Thirty patients were enrolled: the G1 group patients were treated with only scaling and root planning-SRP, the G2 group was treated with SRP and LLLT. Before treatment (T0) all periodontal probing pocket depth and bleeding on probing were obtained. Before (T0) and 10 (T1), 30 (T2) and 60 (T3) days after treatment, was achieved plaque sample and specimens of gingival crevicular fluid. Diode laser wavelength range was used between 600-1000 nm and 0.04-60 J/cm2 energy density for 3-s spotlights.

RESULTS

In all patients PPD, BOP and IL-37 have shown healing improved parameters.

CONCLUSIONS

Although LLLT is widely recommended for its biostimulatory and anti-inflammatory roles, it only showed additional short-term merits in reducing the pocket depth after conventional SRP. Its long-term adjunctive benefits remain unclear. Future RCTs with better study designs, adequate sample power and longer durations of follow-up are required to assess the effectiveness of LLLT as an adjunctive treatment strategy in patients with periodontal disease.

Mast cells in the autonomic nervous system and potential role in disorders with dysautonomia and neuroinflammation

Mast cells (MC) are ubiquitous in the body, and they are critical for not only in allergic diseases but also in immunity and inflammation, including having potential involvement in the pathophysiology of dysautonomias and neuroinflammatory disorders. MC are located perivascularly close to nerve endings and sites such as the carotid bodies, heart, hypothalamus, the pineal gland, and the adrenal gland that would allow them not only to regulate but also to be affected by the autonomic nervous system (ANS). MC are stimulated not only by allergens but also many other triggers including some from the ANS that can affect MC release of neurosensitizing, proinflammatory, and vasoactive mediators. Hence, MC may be able to regulate homeostatic functions that seem to be dysfunctional in many conditions, such as postural orthostatic tachycardia syndrome, autism spectrum disorder, myalgic encephalomyelitis/chronic fatigue syndrome, and Long-COVID syndrome. The evidence indicates that there is a possible association between these conditions and diseases associated with MC activation. There is no effective treatment for any form of these conditions other than minimizing symptoms. Given the many ways MC could be activated and the numerous mediators released, it would be important to develop ways to inhibit stimulation of MC and the release of ANS-relevant mediators.

Emerging functions and therapeutic targets of IL-38 in central nervous system diseases

Interleukin (IL)-38 is a newly discovered cytokine of the IL-1 family, which binds various receptors (i.e., IL-36R, IL-1 receptor accessory protein-like 1, and IL-1R1) in the central nervous system (CNS). The hallmark physiological function of IL-38 is competitive binding to IL-36R, as does the IL-36R antagonist. Emerging research has shown that IL-38 is abnormally expressed in the serum and brain tissue of patients with ischemic stroke (IS) and autism spectrum disorder (ASD), suggesting that IL-38 may play an important role in neurological diseases. Important advances include that IL-38 alleviates neuromyelitis optica disorder (NMOD) by inhibiting Th17 expression, improves IS by protecting against atherosclerosis via regulating immune cells and inflammation, and reduces IL-1β and CXCL8 release through inhibiting human microglial activity post-ASD. In contrast, IL-38 mRNA is markedly increased and is mainly expressed in phagocytes in spinal cord injury (SCI). IL-38 ablation attenuated SCI by reducing immune cell infiltration. However, the effect and underlying mechanism of IL-38 in CNS diseases remain inadequately characterized. In this review, we summarize the biological characteristics, pathophysiological role, and potential mechanisms of IL-38 in CNS diseases (e.g., NMOD, Alzheimer's disease, ASD, IS, TBI, and SCI), aiming to explore the therapeutic potential of IL-38 in the prevention and treatment of CNS diseases.

Association between the neutrophil-to-lymphocyte ratio and risk of in-hospital heart failure and arrhythmia in patients with acute myocardial infarction

Background

This study was to probe into the relationship between the neutrophil-to-lymphocyte ratio (NLR) and both in-hospital and long-term heart failure risk in patients with acute myocardial infarction (AMI).

Methods

990 patients with AMI, including 386 with non-ST-segment elevation myocardial infarction (NSTEMI) and 604 with segment elevation myocardial infarction (STEMI) were recruited between January 2019 and March 2022. The in-hospital acute heart failure (AHF) and arrhythmia events were recorded.

Results

The NLR was significantly greater in the AHF group in STEMI and NSTEMI patients, with a higher frequency of arrhythmia in comparison to the non-AHF group. A high NLR was related to a high level of myocardial injury markers, accompanied with more AHF and arrhythmia events. Multivariate logistic regression analyses revealed that high NLR is independently linked with increased in-hospital AHF and arrhythmia risk. Receiver operating characteristic curve analyses revealed that the prognostic value of NLR for in-hospital AHF was 0.704 in STEMI patients and 0.766 in NSTEMI patients. However, during a median follow-up of 28 months with 32 heart failure patients, there was no significant difference between the low NLR group (n = 18) and the high NLR group (n = 14). Further analysis showed that the two groups did not significantly differ in the occurrence of heart failure within 12 months of discharge.

Conclusion

Our results indicate that NLR is an independent risk factor of in-hospital AHF in AMI patients. However, NLR has no value in predicting long-term heart failure.

Peripheral surgery triggers mast cells activation: Focusing on neuroinflammation

Peripheral surgery can lead to a systemic aseptic inflammatory response comprising several mediators aiming at restoring tissue homeostasis. It induces inflammatory mechanisms through neuroimmune interaction between the periphery and to brain which also plays a critical role in causing cognitive impairments. Accumulating scientific evidence revealed that acute neuroinflammation of the brain triggered by peripheral surgery that causes peripheral inflammation leads to transmitting signals into the brain through immune cells. Mast cells (MCs) play an important role in the acute neuroinflammation induced by peripheral surgical trauma. After peripheral surgery, brain-resident MCs can be rapidly activated followed by releasing histamine, tryptase, and other inflammatory mediators. These mediators then interact with other immune cells in the peripheral and amplify the signal into the brain by disrupting BBB and activating principle innate immune cells of brain including microglia, astrocytes, and vascular endothelial cells, which release abundant inflammatory mediators and in turn accelerate the activation of brain MCs, amplify the cascade effect of neuroinflammatory response. Surgical stress may induce HPA axis activation by releasing corticotropin-releasing hormone (CRH) subsequently influence the activation of brain MCs, thus resulting in impaired synaptic plasticity. Herein, we discuss the better understating of MCs mediated neuroinflammation mechanisms after peripheral surgery and potential therapeutic targets for controlling inflammatory cascades.

The emerging role of IL-38 in diseases: A comprehensive review

INTRODUCTION

Interleukin-38 (IL-38) is a new type of anti-inflammatory cytokine, which is mainly expressed in the immunity-related organs and is involved in various diseases including cardiovascular and cerebrovascular diseases, lung diseases, viral infectious diseases and autoimmune diseases.

AIM

This review aims to detail the biological function, receptors and signaling of IL-38, which highlights its therapeutic potential in related diseases.

CONCLUSION

This article provides a comprehensive review of the association between interleukin-38 and related diseases, using interleukin-38 as a keyword and searching the relevant literature through Pubmed and Web of science up to July 2023.

Nervonic acid improves liver inflammation in a mouse model of Parkinson's disease by inhibiting proinflammatory signaling pathways and regulating metabolic pathways

BACKGROUND

Nervonic acid (NA) - a type of bioactive fatty acid that is found in natural sources - can inhibit inflammatory reactions and regulate immune system balance. Therefore, the use of NA for the treatment of neurodegenerative diseases has received considerable attention. Our previous study found that NA inhibited inflammatory responses in the brain of Parkinson's disease (PD) mouse models. In addition to the brain, PD is also associated with visceral organ dysfunction, especially impaired liver function. Thus, studying the role of NA in PD-mediated inflammation of the liver is particularly important.

METHODS

A combined transcriptome and metabolomic approach was utilized to investigate the anti-inflammatory effects of NA on the liver of PD mice. Inflammatory signaling molecules and metabolic pathway-related genes were examined in the liver using real-time PCR and western blotting.

RESULTS

Liver transcriptome analysis revealed that NA exerted anti-inflammatory effects by controlling several pro-inflammatory signaling pathways, such as the down-regulation of the tumor necrosis factor and nuclear factor kappa B signaling pathways, both of which were essential in the development of inflammatory disease. In addition, liver metabolomic results revealed that metabolites related to steroid hormone biosynthesis, arachidonic acid metabolism, and linoleic acid metabolism were up-regulated and those related to valine, leucine, and isoleucine degradation pathways were down-regulated in NA treatment groups compared with the PD model. The integration of metabolomic and transcriptomic results showed NA significantly exerted its anti-inflammatory function by regulating the transcription and metabolic pathways of multiple genes. Particularly, linoleic acid metabolism, arachidonic acid metabolism, and steroid hormone biosynthesis were the crucial pathways of the anti-inflammatory action of NA. Key genes in these metabolic pathways and key molecules in inflammatory signaling pathways were also verified, which were consistent with transcriptomic results.

CONCLUSION

These findings provide novel insights into the liver protective effects of NA against PD mice. This study also showed that NA could be a useful dietary element for improving and treating PD-induced liver inflammation.