Cytokines, Masticatory Muscle Inflammation, and Pain: an Update

Investigating the role of TGF-β and BDNF in cancer-related depression: a primary cross-sectional study

BACKGROUND

Cancer-related depression is a well-documented condition that significantly impacts long-term quality of life. Brain-derived neurotrophic factor (BDNF), a neurotrophin essential for neurogenesis and neuronal plasticity, has been implicated in various neuropsychological disorders including depression associated with cancer. Cytokines, on the other hand, play a crucial role in regulating depression, potentially by influencing BDNF expression. Transforming growth factor-β (TGF-β), a key immune regulator within the tumor microenvironment, has been found to elevate BDNF levels, establishing a link between peripheral immune responses and depression. The study aims to investigate the correlation of TGF-β and BDNF in cancer-related depression.

METHODS

This study involved a cohort of 153 gynecological patients, including 61 patients with gynecological cancer and 92 patients without cancer. Depression levels were assessed using the subscale of Hospital Anxiety and Depression Scale (HADS-D), and TGF-β and BDNF plasma levels were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

The study revealed elevated plasma TGF-β levels in patients with cancer (32.24 ± 22.93 ng/ml) compared to those without cancer (25.24 ± 19.72 ng/ml) (P = 0.046). Additionally, reduced levels of BDNF were observed in patients presenting depression symptoms (44.96 ± 41.06 pg/ml) compared to those without depression (133.5 ± 176.7 pg/ml) (P = 0.036). Importantly, a significant correlation between TGF-β and BDNF was found in patients without cancer but with depression (correlation coefficient = 0.893, **P < 0.01). Interestingly, cancer appeared to influence the association between TGF-β and BDNF in patients with depression, as evidenced by a significant difference in the correlation of TGF-β and BDNF between cancer and non-cancer groups (P = 0.041).

CONCLUSIONS

These findings underscore the active involvement of TGF-β and BDNF crosstalk in the context of cancer-related depression.

Interactions and Trends of Interleukins, PAI-1, CRP, and TNF-α in Inflammatory Responses during the Perioperative Period of Joint Arthroplasty: Implications for Pain Management-A Narrative Review

Inflammation during the perioperative period of joint arthroplasty is a critical aspect of patient outcomes, influencing both the pathophysiology of pain and the healing process. This narrative review comprehensively evaluates the roles of specific cytokines and inflammatory biomarkers in this context and their implications for pain management. Inflammatory responses are initiated and propagated by cytokines, which are pivotal in the development of both acute and chronic postoperative pain. Pro-inflammatory cytokines play essential roles in up-regulating the inflammatory response, which, if not adequately controlled, leads to sustained pain and impaired tissue healing. Anti-inflammatory cytokines work to dampen inflammatory responses and promote resolution. Our discussion extends to the genetic and molecular influences on cytokine production, which influence pain perception and recovery rates post-surgery. Furthermore, the role of PAI-1 in modulating inflammation through its impact on the fibrinolytic system highlights its potential as a therapeutic target. The perioperative modulation of these cytokines through various analgesic and anesthetic techniques, including the fascia iliac compartment block, demonstrates a significant reduction in pain and inflammatory markers, thus underscoring the importance of targeted therapeutic strategies. Our analysis suggests that a nuanced understanding of the interplay between pro-inflammatory and anti-inflammatory cytokines is required. Future research should focus on individualized pain management strategies.

Phytoconstituents of Androstachys johnsonii Prain Prevent Reactive Oxygen Species Production and Regulate the Expression of Inflammatory Mediators in LPS-Stimulated RAW 264.7 Macrophages

According to a survey, the medicinal use of Androstachys johnsonii Prain is kept secret by traditional healers. Considering that inflammation and oxidative stress are major risk factors for the progression of various chronic diseases and disorders, we resolved to investigate the antioxidant and anti-inflammatory potentials of A. johnsonii using in vitro and cell-based assays. The antioxidant activity of A. johnsonii hydroethanolic leaf extract (AJHLE) was evaluated using the ABTS, DPPH, and FRAP assays. Its cytotoxic effect was assessed on RAW 264.7 macrophages using an MTT assay. Then, its anti-inflammatory effect was evaluated by measuring the NO production and 15-LOX inhibitory activities. Moreover, its preventive effect on ROS production and its regulatory effect on the expression of pro-inflammatory mediators such as IL-1β, IL-10, TNF-α, and COX-2 were determined using established methods. AJHLE strongly inhibited radicals such as ABTS•+, DPPH•, and Fe3+-TPTZ with IC50 values of 9.07 µg/mL, 8.53 µg/mL, and 79.09 µg/mL, respectively. Additionally, AJHLE induced a significant (p < 0.05) cytotoxic effect at 100 µg/mL, and when tested at non-cytotoxic concentrations, it inhibited NO and ROS production in LPS-stimulated RAW 264.7 macrophages in a concentration-dependent manner. Furthermore, AJHLE showed that its anti-inflammatory action occurs via the inhibition of 15-LOX activity, the downregulation of COX-2, TNF-α, and IL-1β expression, and the upregulation of IL-10 expression. Finally, chemical investigation showed that AJHLE contains significant amounts of procyanidin, epicatechin, rutin, and syringic acid which support its antioxidant and anti-inflammatory activities. These findings suggest that A. johnsonii is a potential source of therapeutic agents against oxidative stress and inflammatory-related diseases.

Novel Management of Masticatory Myositis in Three Dogs with a Selective Janus Kinase (JAK-1) Inhibitor

Masticatory myositis (MM) is an inflammatory myopathy reported in dogs and is characterized by inflammation of the masticatory muscles (temporalis, masseter, and pterygoid muscles). Immunosuppressive therapy is the current recommended treatment for MM and may involve glucocorticoids, cyclosporine, azathioprine, mycophenolate mofetil, leflunomide, or a combination of these treatments that are slowly tapered to the lowest effective dose. However, side effects from multimodal medical therapy and complications associated with MM relapses have been reported. The purpose of this case series was to report oclacitinib as a treatment alternative to traditional medical management of MM. The intent of this alternative is to manage side effects from glucocorticoid use. Oclacitinib (1mg/kg per os q12h) was used solely for treatment of MM in three dogs. The dogs were followed up to >6 months after oclacitinib administration. An increase in oral range of motion, as determined by gape angle, was noted in all three dogs. However, a corresponding drop in antibody titers (2M fiber) did not occur. All dogs showed improvement in overall clinical management of MM, side effects from glucocorticoids, and clinical signs related to chronic prednisone use. Larger controlled trials with consistent measurements (interincisal distance, gape angle) and 2M fiber antibody titers are indicated to further assess validation of oclacitinib treatment of MM. The clinical outcome of all dogs was considered successful.

Xueliankoufuye Suppresses Microglial Activation with Inflammatory Pain by Blocking NF-κB Signaling Pathway

Xuelian, as a traditional Chinese ethnodrug, plays an important role in anti-inflammation, immunoregulation, promoting blood circulation, and other physiological functions. It has been prepared into different traditional Chinese medicine preparations for clinical use, with xuelian koufuye (XL) being widely used to treat rheumatoid arthritis. However, whether XL can relieve inflammatory pain and its analgesic molecular mechanism are still unknown. The present study explored the palliative effect of XL on inflammatory pain and its analgesic molecular mechanism. In complete Freund's adjuvant (CFA)-induced inflammatory joint pain, oral XL dose-dependently improved the mechanical withdrawal threshold of inflammatory pain from an average value of 17.8 g to 26.6 g (P < 0.05) and high doses of XL significantly reduced inflammation-induced ankle swelling from an average value of 3.1 cm to 2.3 cm compared to the model group (P < 0.05). In addition, in carrageenan-induced inflammatory muscle pain rat models, oral XL dose-dependently improved the mechanical withdrawal threshold of inflammatory pain from an average value of 34.3 g to 40.8 g (P < 0.05). The phosphorylated p65 was inhibited in LPS-induced BV-2 microglia and spinal cord of mice in CFA-induced inflammatory joint pain within a value of 75% (P < 0.001) and 52% reduction (P < 0.05) on average, respectively. In addition, the results showed that XL could effectively inhibit the expression and secretion of IL-6 from an average value of 2.5 ng/ml to 0.5 ng/ml (P < 0.001) and TNF-α from 3.6 mg/ml to 1.8 ng/ml with IC₅₀ value of 20.15 μg/mL and 112 μg/mL respectively, by activating the NF-κB signaling pathway in BV-2 microglia (P < 0.001). The above-given results provide a clear understanding of the analgesic activity and mechanism of action not found in XL. Considering the significant effects of XL, it can be evaluated as a novel drug candidate for inflammatory pain, which establishes a new experimental basis for expanding the indications of XL in clinical treatment and suggests a feasible strategy to develop natural analgesic drugs.

Gene expression profiling after ochratoxin A treatment in small intestinal epithelial cells from pigs

Ochratoxin A (OTA) is a well-known mycotoxin that causes disease through the ingestion of contaminated food or feed, for example, in the porcine industry. The intestinal epithelium acts as the first barrier against food contamination. We conducted a study on the exposure of the porcine intestinal epithelium to OTA. We used the intestinal porcine epithelial cell line IPEC-J2 as an in vitro model to evaluate the altered molecular mechanisms following OTA exposure. Gene expression profiling revealed that OTA upregulated 782 genes and downregulated 896, totalling 1678 differentially expressed genes. Furthermore, immunofluorescence, quantitative real-time polymerase chain reaction, and western blotting confirmed that OTA damages the tight junction protein ZO-1. Moreover, OTA activated the expression of inflammatory genes (IL-6, IL-8, IL-10, NF-kB, TLR4, and TNF-α). In summary, this study confirmed that OTA alters various molecular mechanisms and has several adverse effects on IPEC-J2 cells.

Epigenetic aging, knee pain and physical performance in community-dwelling middle-to-older age adults

Knee pain is a leading cause of disability in the aging population and may indirectly accelerate biological aging processes. Chronological aging increases the risk of developing of knee pain and knee pain reduces physical function; however, limited data exist on how epigenetic aging, a known hallmark of biological aging shown to predict health span and mortality, may influence this relationship. The purpose of this study was to examine whether decreased physical performance associated with knee pain is mediated by markers of epigenetic aging. Participants (57.91 ± 8.04 years) with low impact knee pain (n = 95), high impact knee pain (n = 53) and pain-free controls (n = 26) completed self-reported pain, a blood draw and a short physical performance battery (SPPB) that included balance, walking, and sit to stand tasks. We employed an epigenetic clock previously associated with knee pain and shown to predict overall mortality risk (DNAmGrimAge). Bootstrapped-mediation analyses were used to determine associations of DNAmGrimAge and SPPB between pain groups. Those with high impact and low impact pain had a biologically older epigenetic age (5.14y ± 5.66 and 1.32y ± 5.41, respectively). However, while there were direct effects of pain on overall physical performance, these were not explained by epigenetic aging. Epigenetic aging only mediated the effect of pain on balance performance. Future work is needed to examine pain's impact on biological aging processes including epigenetic aging and its ultimate effect on physical function measures known to predict health span and mortality.

Effect of Restraint Stress on Pain Sensitivity, Spinal Trigeminal Nucleus Neurons, and Astrocytes in the Masseter Area of Rats

To explore the changes of pain sensitivity (PS) in the masseter area (MA) in the rat model of psychological stress and the mechanism of action between spinal nucleus neurons and astrocytes in the trigeminal ganglion. The 40 Sprague-Dawley rats were randomly divided into control group (no treatment), group A (restraint stress (RS) 1 d), group B (RS 7 d), and group C (RS 14 d). The body weight growth rates (WGR) of rats in each group were compared and the difference of CORT and ACTH in serum was analyzed by ELISA. The open field test and the elevated “cross” maze test were adopted to detect the behavioral changes of rats. Finally, pain threshold of the MA in rats, the activation amount of brain tissue medulla oblongata parts astrocytes markers Glial fibrillary acidic protein (GFAP), and the protein expression of IL-1β and IL-1RI were detected. The results showed the WGR at 7 d and 14 d was greatly lower than control group (P < 0.01). In addition, the activity level and serum CORT and ACTH levels AND mean pain threshold in the MA of groups B and C were greatly lower than control group (P < 0.05). The activation rate of GFRP in group C (P < 0.01) and the protein expression of IL-1β and IL-1RI (P < 0.05) in rat trigeminal ganglion astrocytes of groups B and C was greatly higher than control group, indicating the increase of RS time, the release of IL-1β and IL-1RI can activate neurons and astrocytes in spinal trigeminal nucleus (STN) nerve and increase the PS of the MA.

Engineering the surfaces of orthopedic implants with osteogenesis and antioxidants to enhance bone formation in vitro and in vivo

Limited osteointegration of orthopedic implants with surrounding tissues has been the leading issue until the failure of orthopedic implants in the long term, which could be induced by multiple factors, including infection, limited abilities for bone formation and remodeling, and an overstressed reactive oxygen species (ROS) environment around implants. To address this challenge, a multifunctional coating composed of tannic acid (TA), nanohydroxyapatite (nHA) and gelatin (Gel) was fabricated by a layer-by-layer (LBL) technique, into which TA, nHA, and Gel were integrated, and their respective functions were utilized to synergistically promote osteogenesis. The fabrication process of (TA@nHA/Gel)_n coatings and related bio-multifunctionalities were thoroughly investigated by various techniques. We found that the (TA@nHA/Gel)_n coatings showed strong antioxidant activity and accelerated cellular attachment in the early stage and proliferation in the long term, largely enhancing osteogenesis in vitro and promoting bone formation in vivo. We believe our findings will guide the design of orthopedic implants in the future, and the strategy developed here could pave the way for multifunctional orthopedic implant coating and protein-related coatings with various potential applications, including biosensors, catalysis, tissue engineering, and life science.

Dynamic monocyte chemoattractant protein-1 level as predictors of perceived pain during first and second phacoemulsification eye surgeries in patients with bilateral cataract

Background

The purpose of the study was to investigate whether dynamic monocyte chemoattractant protein-1 (MCP-1) level might be as predictors of perceived pain during the first and second phacoemulsification eye surgeries in patients with bilateral cataract.

Methods

Consecutive bilateral cataract patients undergoing bilateral sequential phacoemulsification were retrospectively enrolled. Patients’ preoperative anxiety score and intraoperative pain score were registered. Aqueous humor samples were obtained during surgery. MCP-1 level in the aqueous humor was measured by enzyme linked immunosorbent assay (Elisa). Patients were assigned to seven subgroups based on the interval between first-eye and second-eye cataract surgery. Comparisons were performed for a subjective sensation and MCP-1 levels among different subgroups.

Results

pain score during second-eye surgery was significantly higher than during first-eye surgery. Whereas there was no statistical difference in anxiety score between both surgeries. Result from subgroups comparison showed that the visual analog scale (VAS) pain score was statistically greater in 1-group and 6-group during the second eye surgery. Anxiety score did not statistically differ in subgroups. Additionally, the second-eye MCP-1 level was significantly higher at week 1and 6 intervals. Preoperative MCP-1 level was positively correlated with perceiving pain score during both surgeries.

Conclusions

MCP-1 level in aqueous humor significantly correlated with perceived pain during cataract surgery. Dynamic MCP-1 level could function as predictors of perceived pain during the first and second phacoemulsification eye surgeries in patients with bilateral cataract, which might support clinicians in treatment optimization and clinical decision-making.

Emerging Antioxidant Paradigm of Mesenchymal Stem Cell-Derived Exosome Therapy

Mesenchymal stem cell-derived exosomes have been under investigation as potential treatments for a diverse range of diseases, and many animal and clinical trials have achieved encouraging results. However, it is well known that the biological activity of the exosomes is key to their therapeutic properties; however, till date, it has not been completely understood. Previous studies have provided different explanations of therapeutic mechanisms of the exosomes, including anti-inflammatory, immunomodulatory, and anti-aging mechanisms. The pathological effects of oxidative stress often include organ damage, inflammation, and disorders of material and energy metabolism. The evidence gathered from research involving animal models indicates that exosomes have antioxidant properties, which can also explain their anti-inflammatory and cytoprotective effects. In this study, we have summarized the antioxidant effects of exosomes in in vivo and in vitro models, and have evaluated the anti-oxidant mechanisms of exosomes by demonstrating a direct reduction in excessive reactive oxygen species (ROS), promotion of intracellular defence of anti-oxidative stress, immunomodulation by inhibiting excess ROS, and alteration of mitochondrial performance. Exosomes exert their cytoprotective and anti-inflammatory properties by regulating the redox environment and oxidative stress, which explains the therapeutic effects of exosomes in a variety of diseases, mechanisms that can be well preserved among different species.

Muscle-Bone Crosstalk in the Masticatory System: From Biomechanical to Molecular Interactions

The masticatory system is a complex and highly organized group of structures, including craniofacial bones (maxillae and mandible), muscles, teeth, joints, and neurovascular elements. While the musculoskeletal structures of the head and neck are known to have a different embryonic origin, morphology, biomechanical demands, and biochemical characteristics than the trunk and limbs, their particular molecular basis and cell biology have been much less explored. In the last decade, the concept of muscle-bone crosstalk has emerged, comprising both the loads generated during muscle contraction and a biochemical component through soluble molecules. Bone cells embedded in the mineralized tissue respond to the biomechanical input by releasing molecular factors that impact the homeostasis of the attaching skeletal muscle. In the same way, muscle-derived factors act as soluble signals that modulate the remodeling process of the underlying bones. This concept of muscle-bone crosstalk at a molecular level is particularly interesting in the mandible, due to its tight anatomical relationship with one of the biggest and strongest masticatory muscles, the masseter. However, despite the close physical and physiological interaction of both tissues for proper functioning, this topic has been poorly addressed. Here we present one of the most detailed reviews of the literature to date regarding the biomechanical and biochemical interaction between muscles and bones of the masticatory system, both during development and in physiological or pathological remodeling processes. Evidence related to how masticatory function shapes the craniofacial bones is discussed, and a proposal presented that the masticatory muscles and craniofacial bones serve as secretory tissues. We furthermore discuss our current findings of myokines-release from masseter muscle in physiological conditions, during functional adaptation or pathology, and their putative role as bone-modulators in the craniofacial system. Finally, we address the physiological implications of the crosstalk between muscles and bones in the masticatory system, analyzing pathologies or clinical procedures in which the alteration of one of them affects the homeostasis of the other. Unveiling the mechanisms of muscle-bone crosstalk in the masticatory system opens broad possibilities for understanding and treating temporomandibular disorders, which severely impair the quality of life, with a high cost for diagnosis and management.