Neuroimmune interaction in inflammatory diseases

Research journey into multiple-sensor theory

In 1998, I was asked by the American Physiological Society to review a book written by Dr. Michael de Burgh Daly, Peripheral Arterial Chemoreceptors and Respiratory-Cardiovascular Integration. Inspired by this work, I came to appreciate how researchers in the later stages of their careers and who provide a detailed review of their experimental approach might effectively contribute to science, especially to the benefit of young scientists (Yu J. The Physiologist 41: 231, 1998.). This article is written in that vein. Over several decades of intensive investigation of cardiopulmonary reflexes, focused on the sensory receptors, my colleagues and I advanced a novel multiple-sensor theory (MST) to explain the role of the vagal mechanosensory system. Described here is our research journey through various stages of developing MST and the process of how the problem was identified, approached, and tackled. MST redefines conventional mechanosensor doctrines and is supported by new studies that clarify a century of research data. It entails reinterpretation of many established findings. Hopefully, this article will benefit young scientists, such as graduate and postdoctoral students in the cardiopulmonary sensory research field.

Endocrine responses of the stress system to different types of exercise

Physical activity is an important part of human lifestyle although a large percentage of the population remains sedentary. Exercise represents a stress paradigm in which many regulatory endocrine systems are involved to achieve homeostasis. These endocrine adaptive responses may be either beneficial or harmful in case they exceed a certain threshold. The aim of this review is to examine the adaptive endocrine responses of hypothalamic-pituitary-adrenal axis (HPA), catecholamines, cytokines, growth hormone (GH) and prolactin (PRL) to a single bout or regular exercise of three distinct types of exercise, namely endurance, high-intensity interval (HIIE) and resistance exercise. In summary, a single bout of endurance exercise induces cortisol increase, while regular endurance exercise-induced activation of the HPA axis results to relatively increased basal cortisolemia; single bout or regular exercise induce similar GH peak responses; regular HIIE training lowers basal cortisol concentrations, while catecholamine response is reduced in regular HIIE compared with a single bout of HIIE. HPA axis response to resistance exercise depends on the intensity and volume of the exercise. A single bout of resistance exercise is characterized by mild HPA axis stimulation while regular resistance training in elderly results in attenuated inflammatory response and decreased resting cytokine concentrations. In conclusion, it is important to consider which type of exercise and what threshold is suitable for different target groups of exercising people. This approach intends to suggest types of exercise appropriate for different target groups in health and disease and subsequently to introduce them as medical prescription models.

Macrophages and glial cells: Innate immune drivers of inflammatory arthritic pain perception from peripheral joints to the central nervous system

Millions of people suffer from arthritis worldwide, consistently struggling with daily activities due to debilitating pain evoked by this disease. Perhaps the most intensively investigated type of inflammatory arthritis is rheumatoid arthritis (RA), where, despite considerable advances in research and clinical management, gaps regarding the neuroimmune interactions that guide inflammation and chronic pain in this disease remain to be clarified. The pain and inflammation associated with arthritis are not isolated to the joints, and inflammatory mechanisms induced by different immune and glial cells in other tissues may affect the development of chronic pain that results from the disease. This review aims to provide an overview of the state-of-the-art research on the roles that innate immune, and glial cells play in the onset and maintenance of arthritis-associated pain, reviewing nociceptive pathways from the joint through the dorsal root ganglion, spinal circuits, and different structures in the brain. We will focus on the cellular mechanisms related to neuroinflammation and pain, and treatments targeting these mechanisms from the periphery and the CNS. A comprehensive understanding of the role these cells play in peripheral inflammation and initiation of pain and the central pathways in the spinal cord and brain will facilitate identifying new targets and pathways to aide in developing therapeutic strategies to treat joint pain associated with RA.

White Blood Cell Count and Serum Cytokine Profile in Tropical Hardwood Workers in Kumasi

Background

Occupational exposure to wood dust particles has long been reported of its associated varying degrees of negative health effects due to different extractive chemicals present in the various timber species. However, tropical hardwood is also reported to have higher levels of extractive chemicals of antihistamine, antioxidant, and anti-inflammatory properties. In Ghana, woodworkers have for years been exposed to wood dust from mixed tropical hardwood species, with little or no protective equipment such as nose masks, yet with less significant respiratory conditions. This study seeks to investigate the serum cytokine profile in tropical hardwood workers in Kumasi to provide a better understanding of the immunoregulatory pattern activated in the woodworkers.

Method

The study was carried out among woodworkers, teachers, and security men located in Kumasi. A cross-sectional sampling of adult male workers was selected to participate in the study (86 woodworkers and 89 nonwoodworkers). Participants donated blood collected by venepuncture into EDTA tubes and spun to separate serum for cytokine assay. Cytokines including IFN-gamma, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IL-13, and IL-17 were assayed using the Human Premixed Multianalyte Kit (R&D System, Inc., Minneapolis, USA) following the manufacturer's procedure. The cytokine levels were quantified using the Luminex∗200 analyser.

Results

The mean concentration levels for the various cytokines were significantly different (p < 0.05) between woodworkers and nonwoodworkers except IL-2. There were significantly increased levels of Th1 and Th2 cytokines expressed in the woodworkers more than the nonwoodworkers.

Conclusions

The results from this study reveal that exposed woodworkers of mixed tropical hardwood species show a high level of Th1 and Th2 cytokines in their serum than nonwoodworkers.

The functions of CD4 T-helper lymphocytes in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) has been increasingly accounted for global morbidity and mortality worldwide. Although it is partially reversible, the obstructive ventilatory schema of COPD often causes chronic inflammation that primarily affects peripheral airways, pulmonary parenchyma, and the development of lung lymphoid follicles. Among various T-helper (Th) cell types associated with COPD, Th1, Th2 and Th17 cell numbers are increased in COPD patients, whereas Treg cell number is reduced. Here, we reviewed recent advance in understanding the roles of Th1/Th2 and Th17/Treg in the pathogenesis of COPD and discussed the potential underlying mechanism.

Effect of an 8-Week Yoga-Based Lifestyle Intervention on Psycho-Neuro-Immune Axis, Disease Activity, and Perceived Quality of Life in Rheumatoid Arthritis Patients: A Randomized Controlled Trial

Various external stressors and environmental challenges lead to the provocation of the immune system in autoimmune diseases like Rheumatoid arthritis (RA). The inappropriate immune response further triggers the cascade of inflammatory changes resulting in precipitation of symptoms and hampers quality of life (QOL). The underlying psycho-somatic component of the disease requires a holistic approach to its treatment dimension rather than the use of pharmacotherapy. The applicability of mind-body interventions has become essential in today’s fast-paced life. Yoga, a mind-body technique, alters the mind’s capacity to facilitate systemic functioning at multiple organ system levels. Hence, we conducted this study to evaluate the impact of 8 weeks of a yoga-based lifestyle intervention (YBLI) on psycho-neuro-immune markers, gene expression patterns, and QOL in RA patients on routine medical therapy. A total of 66 patients were randomized into two groups: yoga group or non-yoga group and were assessed for a panel of inflammatory cytokines (IL-6, IL-17A, TNF-α, and TGF-β), mind-body communicative markers (BDNF, DHEAS, β-endorphin, and sirtuin) and transcript levels of various genes (IL-6, TNF-α, NFKB1, TGF-β, and CTLA4). We assessed disease activity and QOL using the DAS28-ESR and WHOQOL-BREF questionnaire, respectively. Yoga group observed significant improvements in the levels of markers, which influenced the psycho-neuro-immune axis (p < 0.001) with an estimated effect size from small to medium range. In the yoga group, there was a significant reduction in DAS28-ESR (p < 0.001) and improvement seen in the physical health, psychological, social relationships domains (p < 0.001) of QOL, except environmental (p > 0.05). The yoga group showed downregulation of IL-6, TNF-α, and CTLA4 and upregulation of TGF-β. These results suggest that a decrease in disease activity after yoga practice is associated with a significant reduction in inflammatory cytokines, the elevation of mind-body communicative markers, and normalization of various transcript levels, which improved QOL. Thus the adoption of YBLI improves clinical outcome in RA, and decreases systemic inflammation by its beneficial effects on psycho-neuro-immune axis and normalization of dysregulated transcripts. Thus YBLI may be used for RA patients as an adjunctive therapy.

General theory of inflammation: patient self-administration of hydrocortisone safely achieves superior control of hydrocortisone-responding disorders by matching dosage with symptom intensity

Objective: To determine if patient self-administration of hydrocortisone will safely achieve superior symptom control for all hydrocortisone-responding disorders as it does for Addison's disease and rheumatoid arthritis. Methods: Two thousand four hundred and twenty-eight participants with hydrocortisone-responding disorders were brought to a minimum symptom state using daily administered hydrocortisone tablets in a 24-week, open study. Thereafter, participants used 5-day, low-dose hydrocortisone regimens to quench subsequent disorder exacerbations (flares) to maintain the minimum symptom state. Stressors such as emotional traumas, infections, allergies, and injuries were minimized to reduce disorder intensity, hydrocortisone consumption, and participant discomfort. Results: Two thousand fifteen participants, 601 with fibromyalgia, 579 with osteoarthritis, 246 with rheumatoid arthritis, 226 with undifferentiated arthritis, 75 with back pain, 51 with Parkinson's disease, 44 with polymyalgia rheumatica, 25 with neuropathy, 25 with chronic fatigue syndrome, 25 with dementia, 21 with migraine headache, 19 with multiple sclerosis, and 78 with other disorders completed the 24-week study to achieve a composite average symptom improvement of 76% with equal response rates. The participants averaged ingesting 12 mg of hydrocortisone per day. No significant adverse reactions were observed. Conclusions: Patient self-administration of hydrocortisone safely achieves superior symptom control for 38 hydrocortisone-responding disorders at equal rates and symptom improvements to confirm and amplify an earlier double-blind study finding on rheumatoid arthritis. These results are consistent with the body having an inflammation control system and chronic inflammation being a disorder unto itself with differing symptoms sets dependent on its location. Clinical Trials Government Identifier: NCT03558971.

Morphological changes during the formation of amoebic liver abscess in vagotomized hamsters

Amoebic liver abscess (ALA) is the main extra-intestinal complication caused by Entamoeba histolytica. Given the histological features of ALA in hamsters and the importance of the vagus nerve in the immune response, the aim of this study was to identify and analyze the major changes in ALA that are caused by a vagotomy. The changes found are related to inflammatory foci and abscess size, the type of collagen formed, and the number of trophozoites in lesions. Male hamsters were divided into three groups: Intact animals (IA) and those undergoing a false operation (SHAM) or a subdiaphragmatic vagotomy (VAG). In each group, E. histolytica trophozoites or culture medium (CM) were inoculated in hamsters by the intrahepatic route, and then euthanized at 6h, 12h, 24h, 48h, 4d or 7d post-infection. Initially the growth of the abscess was more rapid in the VAG group, but at day 7 it was faster in the IA and SHAM groups. VAG animals showed a higher quantity of type III collagen than the IA and SHAM groups. A larger number of amoebic trophozoites/mm² was observed up to day 4 in VAG hamsters (23.3±2.19) compared to IA (14.6±0.23) and SHAM (6.13±0.87) animals. This parameter decreased by day 7 in VAG (13.4±0.87) with respect to IA (24.7±1.47) and SHAM (21.7±1.48). The results show that a subdiaphragmatic vagotomy influenced the development of ALA in hamsters, suggesting a modification of the morphological structure of damaged hepatic tissue.

Traumatic Stress Epigenetics

Purpose of Review

Traumatic stress has profound impacts on many domains of life, yet the mechanisms that confer risk for or resilience to the development of traumatic stress-related psychopathologies are still very much under investigation. The current review highlights recent developments in the field of traumatic stress epigenetics in humans.

Recent Findings

Recent results reveal traumatic stress-related epigenetic dysregulation in neural, endocrine, and immune system genes and associated networks. Emerging work combining imaging with epigenetic measures holds promise for addressing the correspondence between peripheral and central effects of traumatic stress. A growing literature is also documenting the transgenerational effects of prenatal stress exposures in humans.

Summary

Moving forward, increasing focus on epigenetic marks of traumatic stress in CNS tissue will create a clearer picture of the relevance of peripheral measures; PTSD brain banks will help in this regard. Similarly, leveraging multigenerational birth cohort data will do much to clarify the extent of transgenerational epigenetic effects of traumatic stress. Greater efforts should be made towards developing prospective studies with longitudinal design.

Effect of natural neosporosis on bull sperm quality

Neospora is one of the protozoans that can infect the male and female's reproduction system. Despite the existence of N. caninum in the genitalia, its effect on sperm characteristics was not studied yet. Therefore, the aim of this study was to investigate the influence of natural neosporosis on the sperm parameters of bulls. Using 30 bulls with neosporosis diagnosed by modified agglutination test and enzyme-linked immunosorbent assay (ELISA) and 15 healthy bulls, some sperm parameters such as sperm concentration, viability, motility, and morphology were studied and compared. Also, the activity of super oxide dismutase (SOD), glutathione peroxidase (GPX), and malondialdehyde (MDA) level as the biomarker of lipid peroxidation was investigated. Results showed that sperm concentration, viability, and motility were significantly lower in bulls with neosporosis in the present study. There were no significant differences in activities of SOD and MDA level but GPX activity was significantly increased in infected bulls.

Neuroimmune expression in hip osteoarthritis: a systematic review

BACKGROUND

Neuroimmune axis is central in the physiopathology of hip osteoarthritis (OA), but its specific pathways are still unclear. This systematic review aims to assess the nervous and immune system profile of patients with hip osteoarthritis (OA) when compared to healthy controls.

METHODS

A systematic review followed PRISMA guidelines was conducted. A two-step selection process was completed, and from 609 references 17 were included. The inclusion criteria were: original articles on adult patients with hip OA, with assessment of neuroimmune expression. Articles with other interventions prior to analysis and those without a control group were excluded.

RESULTS

Thirty-nine relevant neuroimmune markers were identified, with assessments in bone, cartilage, synovial membrane, synovial fluid, whole blood, serum and/or immune cells. GM-CSF, IFN-γ, IL-1α, IL-6, IL-8, IL-1 and TNF-α presented variable expression among tissues studied when compared between hip OA and controls. VEGFs and TGF-ß isoforms showed similar tendencies among tissues and studies. On nervous expression, CGRP, Tuj-1 and SP were increased in synovial membrane. Overall, patients with hip OA presented a higher number of overexpressed markers.

CONCLUSIONS

For the first time a systematic review on neuroimmune expression in patients with hip OA found an upregulation of neuroimmune markers, with deregulated balance between pro and anti-inflammatory cytokines. However, no clear systematic pattern was found, and few information is available on nervous expression. This highlights the importance of future research with clear methodologies to guide the management of these patients.

The Effect of Quercetin on Pro- and Anti-Inflammatory Cytokines in a Prenatally Stressed Rat Model of Febrile Seizures

Febrile seizures are childhood convulsions resulting from an infection that leads to an inflammatory response and subsequent convulsions. Prenatal stress has been shown to heighten the progression and intensity of febrile seizures. Current medications are costly and have adverse effects associated with prolonged use. Quercetin flavonoid exhibits anti-inflammatory, anti-convulsant, and anti-stress effects. This study was aimed to investigate the therapeutic effect of quercetin in a prenatally stressed rat model of febrile seizures. We hypothesized that quercetin will alleviate the effects of prenatal stress in a febrile seizure rat model. On gestational day 13, Sprague-Dawley rat dams were subjected to restraint stress for 1 hour/d for 7 days. Febrile seizures were induced on postnatal day 14 on rat pups by intraperitoneally injecting lipopolysaccharide followed by kainic acid and quercetin on seizure onset. Hippocampal tissue was harvested to profile cytokine concentrations. Our results show that quercetin suppresses prenatal stress–induced pro-inflammatory marker (interleukin 1 beta) levels, subsequently attenuating febrile seizures. This shows that quercetin can be therapeutic for febrile seizures in prenatally stressed individuals.

Nociception and role of immune system in pain

Both pain and inflammation are protective responses. However, these self-limiting conditions (with well-established negative feedback loops) become pathological if left uncontrolled. Both pain and inflammation can interact with each other in a multi-dimensional manner. These interactions are known to create an array of 'difficult to manage' pathologies. This review explains in detail the role of immune system and the related cells in peripheral sensitization and neurogenic inflammation. Various neuro-immune interactions are analyzed at peripheral, sensory and central nervous system levels. Innate immunity plays a critical role in central sensitization and in establishing acute pain as chronic condition. Moreover, inflammatory mediators also exhibit psychological effects, thus contributing towards the emotional elements associated with pain. However, there is also a considerable anti-inflammatory and analgesic role of immune system. This review also attempts to enlist various novel pharmacological approaches that exhibit their actions through modification of neuro-immune interface.

Mechanisms of neutrophil accumulation in the lungs against bacteria

Bacterial lung diseases are a major cause of morbidity and mortality both in immunocompromised and in immunocompetent individuals. Neutrophil accumulation, a pathological hallmark of bacterial diseases, is critical to host defense, but may also cause acute lung injury/acute respiratory distress syndrome. Toll-like receptors, nucleotide-binding oligomerization domain (NOD)-like receptors, transcription factors, cytokines, and chemokines play essential roles in neutrophil sequestration in the lungs. This review highlights our current understanding of the role of these molecules in the lungs during bacterial infection and their therapeutic potential. We also discuss emerging data on cholesterol and ethanol as environmentally modifiable factors that may impact neutrophil-mediated pulmonary innate host defense. Understanding the precise molecular mechanisms leading to neutrophil influx in the lungs during bacterial infection is critical for the development of more effective therapeutic and prophylactic strategies to control the excessive host response to infection.

Inflammatory mechanisms in the lung

Inflammation is the body's response to insults, which include infection, trauma, and hypersensitivity. The inflammatory response is complex and involves a variety of mechanisms to defend against pathogens and repair tissue. In the lung, inflammation is usually caused by pathogens or by exposure to toxins, pollutants, irritants, and allergens. During inflammation, numerous types of inflammatory cells are activated. Each releases cytokines and mediators to modify activities of other inflammatory cells. Orchestration of these cells and molecules leads to progression of inflammation. Clinically, acute inflammation is seen in pneumonia and acute respiratory distress syndrome (ARDS), whereas chronic inflammation is represented by asthma and chronic obstructive pulmonary disease (COPD). Because the lung is a vital organ for gas exchange, excessive inflammation can be life threatening. Because the lung is constantly exposed to harmful pathogens, an immediate and intense defense action (mainly inflammation) is required to eliminate the invaders as early as possible. A delicate balance between inflammation and anti-inflammation is essential for lung homeostasis. A full understanding of the underlying mechanisms is vital in the treatment of patients with lung inflammation. This review focuses on cellular and molecular aspects of lung inflammation during acute and chronic inflammatory states.