Degenerative Joint Diseases and Neuroinflammation

Sexual dysfunction and self-perceived sexual health in patients with rheumatoid arthritis and systemic lupus erythematosus: results from a cross-sectional survey

Sexual dysfunction (SD) has been associated with worse quality of life and higher disease activity in patients with rheumatic diseases, yet it is still not regularly addressed during routine rheumatologic evaluations. This study aimed to determine the prevalence of sexual dysfunction in patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) and evaluate their perception of their sexual health. We performed a retrospective study in an outpatient rheumatology clinic to evaluate patients over 18 years old with a diagnosis of RA or SLE through the Spanish version of the Arizona Sexual Experiences Scale (ASEX) and the Sexual Health Perception Survey (SHEPS), a questionnaire of 6 items designed in our clinic. Additionally, we applied the Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F version 4) and the Hospital Anxiety and Depression Scale (HADS). A total of 567 patients were evaluated with SHEPS, most of whom were women with a median age of 50 years (IQR: 34) and a median disease duration of 5 years (IQR: 9). Through the ASEX, we found that 67% of the patients with RA and 60% of the patients with SLE experienced SD. Patients reported the level of sex drive, arousal, and the ability to achieve orgasms as the areas with the most difficulties. Most patients did not know their disease could affect their sexuality and had never addressed these issues with their rheumatologists, but almost all of them were willing to. Our findings highlight the importance of addressing sexual health issues regularly during rheumatologic evaluations.

Thermal threshold for knee osteoarthritis people evaluated with infrared thermography: A scoping review

INTRODUCTION

Knee degenerative processes, such as osteoarthritis, are disabling. An early intervention is generally more effective making important a timely diagnosis. A pre-diagnosis tool could be the thermal camera that allows the detection of joint inflammation. Consequently, the objective of the present study was to evaluate the literature and propose a thermal attention threshold for infrared thermography data in people with knee osteoarthritis.

METHODS

four electronic databases were searched with specific keywords until the 25th of March 2024. Only original articles about joint inflammation due to osteoarthritis evaluated through digital infrared thermal images were included. A quality assessment analysis was performed. The attention threshold was extracted through the median of the extracted data. The findings were narratively discussed.

RESULTS

A total of 9 studies have been included after the eligibility criteria selection. The studies presented some differences in terms of acquisition protocol, thermal imaging camera, data extrapolation, and analysis. Despite these differences, the studies presented similar thermal data.

CONCLUSION

A knee thermography of or above 31.3 °C could indicate osteoarthritis, highlighting the necessity of further, more specific, and accurate analysis.

Cartilage tissue engineering using decellularized biomatrix hydrogel containing TGF-β-loaded alginate microspheres in mechanically loaded bioreactor

Physiochemical tissue inducers and mechanical stimulation are both efficient variables in cartilage tissue fabrication and regeneration. In the presence of biomolecules, decellularized extracellular matrix (ECM) may trigger and enhance stem cell proliferation and differentiation. Here, we investigated the controlled release of transforming growth factor beta (TGF-β1) as an active mediator of mesenchymal stromal cells (MSCs) in a biocompatible scaffold and mechanical stimulation for cartilage tissue engineering. ECM-derived hydrogel with TGF-β1-loaded alginate-based microspheres (MSs) was created to promote human MSC chondrogenic development. Ex vivo explants and a complicated multiaxial loading bioreactor replicated the physiological conditions. Hydrogels with/without MSs and TGF-β1 were highly cytocompatible. MSCs in ECM-derived hydrogel containing TGF-β1/MSs showed comparable chondrogenic gene expression levels as those hydrogels with TGF-β1 added in culture media or those without TGF-β1. However, constructs with TGF-β1 directly added within the hydrogel had inferior properties under unloaded conditions. The ECM-derived hydrogel group including TGF-β1/MSs under loading circumstances formed better cartilage matrix in an ex vivo osteochondral defect than control settings. This study demonstrates that controlled local delivery of TGF-β1 using MSs and mechanical loading is essential for neocartilage formation by MSCs and that further optimization is needed to prevent MSC differentiation towards hypertrophy.

Electroacupuncture Alleviates Pain by Suppressing P2Y12R-Dependent Microglial Activation in Monoarthritic Rats

Electroacupuncture (EA) effectively improves arthritis-induced hyperalgesia and allodynia by repressing spinal microglial activation, which plays a crucial role in pain hypersensitivity following tissue inflammation. However, the mechanism by which EA suppresses spinal microglial activation in monoarthritis (MA) remains unclear. In the present study, a rat model of MA was established through unilateral ankle intra-articular injection of complete Freund's adjuvant (CFA). The relationship among P2Y12 receptor (P2Y12R) expression, spinal microglial activation, and EA analgesia was investigated using quantitative real-time PCR (qRT‒PCR), western blotting, immunofluorescence (IF), and behavioral testing. The results found that EA treatment at the ipsilateral "Huantiao" (GB30) and "Yanglingquan" (GB34) acupoints markedly attenuated pain and spinal microglia M1 polarization in MA rats. In particular, P2Y12R expression was significantly increased at the mRNA and protein levels in the spinal dorsal horn in MA rats, whereas EA treatment effectively repressed the MA-induced upregulation of P2Y12R. IF analysis further revealed that most P2Y12R was expressed in microglia in the spinal dorsal horn. Pharmacological inhibition of P2Y12R by its antagonist (AR-C69931MX) decreased MA-induced spinal microglial activation and subsequent proinflammatory cytokine production. Consequently, AR-C69931MX significantly intensified the anti-pain hypersensitive function of EA in MA rats. Taken together, these results demonstrate that EA alleviates MA-induced pain by suppressing P2Y12R-dependent microglial activation.

Potential therapeutic strategies for osteoarthritis via CRISPR/Cas9 mediated gene editing

Osteoarthritis (OA) is an incapacitating and one of the most common physically degenerative conditions with an assorted etiology and a highly complicated molecular mechanism that to date lacks an efficient treatment. The capacity to design biological networks and accurately modify existing genomic sites holds an apt potential for applications across medical and biotechnological sciences. One of these highly specific genomes editing technologies is the CRISPR/Cas9 mechanism, referred to as the clustered regularly interspaced short palindromic repeats, which is a defense mechanism constituted by CRISPR associated protein 9 (Cas9) directed by small non-coding RNAs (sncRNA) that bind to target DNA through Watson-Crick base pairing rules where subsequent repair of the target DNA is initiated. Up-to-date research has established the effectiveness of the CRISPR/Cas9 mechanism in targeting the genetic and epigenetic alterations in OA by suppressing or deleting gene expressions and eventually distributing distinctive anti-arthritic properties in both in vitro and in vivo osteoarthritic models. This review aims to epitomize the role of this high-throughput and multiplexed gene editing method as an analogous therapeutic strategy that could greatly facilitate the clinical development of OA-related treatments since it's reportedly an easy, minimally invasive technique, and a comparatively less painful method for osteoarthritic patients.

Experiences and perspectives related to shared decision-making among outpatients with degenerative joint disease in Taiwan: a qualitative study

OBJECTIVES

Various treatment options are available for degenerative joint disease (DJD). During clinical visits, patients and clinicians collaboratively make decisions regarding the optimal treatment for DJD; this is the essence of shared decision-making (SDM). Here, we collated and assessed the SDM-related experiences and perspectives of outpatients with DJD in Taiwan.

DESIGN

In-depth interviews and thematic analysis.

SETTING

Primary care clinics of a regional teaching hospital in Taiwan, October 2021-May 2022.

PARTICIPANTS

21 outpatients with at least three visits for DJD and who were aware of SDM.

RESULTS

Four main themes emerged in this study: first, equipping themselves with knowledge: outpatients obtained disease-related and treatment-related knowledge in various ways-seeking relevant information online, discussing with family and friends, learning from their own experiences or learning from professionals. Second, shared or not shared: physicians had different patterns for communicating with patients, particularly when demonstrating authority, performing mutual discussion, respecting patient preferences or responding perfunctorily. Third, seldom saying no to physician-prescribed treatment plans during clinical visits: most patients respected physicians' professionalism; however, some patients rejected physicians' recommendations indirectly, whereas some responded depending on their disease prognosis. Fourth, whose call?-participants decided to accept or reject a treatment plan independently or by discussing it with their families or by obeying their physicians' recommendations.

CONCLUSIONS

In general, patients with DJD sought reliable medical information from various sources before visiting doctors; however, when having a conversation with patients, physicians dominated the discussion on treatment options. The patient-physician interaction dynamics during the SDM process determined the final medical decision, which was in accordance with either patients' original autonomy or physicians' recommendations. To alleviate medical paternalism and physician dominance, patients should be empowered to engage in medical decision-making and share their opinions or concerns with their physicians. Family members should also be included in SDM.

Potential Role of Oxidative Stress in the Pathophysiology of Neurodegenerative Disorders

Neurodegeneration causes premature death in the peripheral and central nervous system. Neurodegeneration leads to the accumulation of oxidative stress, inflammatory responses, and the generation of free radicals responsible for nervous disorders like amyotrophic lateral sclerosis, Alzheimer's disease, Parkinson's disease, and Huntington's disorders. Therefore, focus must be diverted towards treating and managing these disorders, as it is very challenging. Furthermore, effective therapies are also lacking, so the growing interest of the global market must be inclined towards developing newer therapeutic approaches that can intercept the progression of neurodegeneration. Emerging evidences of research findings suggest that antioxidant therapy has significant potential in modulating disease phenotypes. This makes them promising candidates for further investigation. This review focuses on the role of oxidative stress and reactive oxygen species in the pathological mechanisms of various neurodegenerative diseases, amyotrophic lateral sclerosis, Alzheimer's disease, Parkinson's disease, and Huntington's disorders and their neuroprotection. Additionally, it highlights the potential of antioxidant-based therapeutics in mitigating disease severity in humans and improving patient compliance. Ongoing extensive global research further sheds light on exploring new therapeutic targets for a deeper understanding of disease mechanisms in the field of medicine and biology targeting neurogenerative disorders.

Neuroinflammatory markers in patients with haemophilia and healthy controls: Where are the differences?

INTRODUCTION

People with haemophilia (PwH) suffer from haemophilic arthropathy which is accompanied by acute and chronic inflammation. The aim of this study was to examine the neuroinflammatory network operative in PwH and to compare it to healthy controls.

MATERIAL AND METHODS

Blood samples were collected from 41 PwH (age 54.7 ± 11.7 years) and 33 healthy controls (age 50.9 ± 10.5 years) and the levels of 13 neuroinflammatory markers were analyzed by applying an antibody-based detection kit in a flow cytometer.

RESULTS

From 13 analyzed markers, three-ß-nerve growth factor (ß-NGF), soluble receptor for advanced glycation endproducts (sRAGE) and Interleukin-18 (IL-18) differed significantly between the groups (ß-NGF p = .045; sRAGE p = .003; IL-18 p = .007). While ß-NGF was downregulated in PwH, sRAGE and IL-18 were upregulated. None of the analyzed markers corelated to the joint status of PwH while CCL2 (C-C motif ligand 2 chemokine) correlated to HIV infections in PwH (r = .313, p = .007). Correlation analyses of the markers studied also revealed many differences between PwH and controls suggesting a number of deregulations in PwH.

CONCLUSION

The altered levels of sRAGE and ß-NGF in PwH, which have not been analyzed in PwH before, may help to understand the neuroinflammatory network operative in PwH. The general inflammatory processes in PwH and the involved biomarkers in PwH remain poorly understood. PwH could benefit from new therapies against neuroinflammation which may help to reduce inflammation or also chronic pain.

Potential Joint Protective and Anti-Inflammatory Effects of Integrin αvβ3 in IL-1β-Treated Chondrocytes Cells

In osteoarthritis (OA), the articular cartilage covering the articular surface of the bone wears out, exposing the subchondral bone, and the synovial membrane surrounding the joint becomes inflamed, causing pain and deformity. OA causes pain, stiffness, and swelling, and discomfort in the knee when climbing stairs is a typical symptom. Although drug development studies are conducted to treat these inflammatory joint diseases, it is difficult to find conclusive research results which could reduce inflammation and slow cartilage tear. The development of drugs to relieve inflammatory pain often utilizes inflammatory triggers. Interleukins, one of the proteins in the limelight as pro-inflammatory factors, are immune-system-stimulating factors that promote the body's fight against harmful factors such as bacteria. In this study, inflammation was induced in Chondrocytes cells (Chon-001 cells) with IL-1β and then treated with integrin αvβ3 to show anti-inflammatory and chondrogenesis effects. Integrin αvβ3 was not toxic to Chon-001 cells in any concentration groups treated with or without IL-1β. COX-2 and iNOS, which are major markers of inflammation, were significantly reduced by integrin αvβ3 treatment. Expressions of p-ERK, p-JNK, and p-p38 corresponding to the MAPKs signaling pathway and p-IκBα and p-p65 corresponding to the NF-κB signaling pathway were also decreased in a dose-dependent manner upon integrin αvβ3 treatment, indicating that inflammation was inhibited, whereas treatment with integrin αvβ3 significantly increased the expression of ALP, RUNX2, BMP2, BMP4, Aggrecan, SOX9, and COL2A1, suggesting that osteogenesis and chondrogenesis were induced. These results suggest that integrin αvβ3 in-duces an anti-inflammatory effect, osteogenesis, and chondrogenesis on IL-1β-induced Chon-001 cells.

Investigation and Evaluation of the Transdermal Delivery of Ibuprofen in Various Characterized Nano-Drug Delivery Systems

The aim was to assess the suitability of three nano-based transdermal drug delivery systems containing ibuprofen: a nano-emulsion, a nano-emulgel, and a colloidal suspension with ibuprofen-loaded nanoparticles. Understanding the transdermal delivery of ibuprofen using nano-based drug delivery systems can lead to more effective pain relief and improved patient compliance. Characterization tests assessed the suitability of the developed drug delivery systems. Membrane release and skin diffusion studies, along with tape stripping, were performed to determine drug release and skin permeation of ibuprofen. In vitro cytotoxicity studies on HaCaT cells were conducted using MTT and neutral red assays to evaluate the safety of the developed drug delivery systems. Characterization studies confirmed stable drug delivery systems with ideal properties for transdermal delivery. Membrane release studies demonstrated the successful release of ibuprofen. In vitro skin diffusion experiments and tape stripping, detecting ibuprofen in the receptor phase, stratum corneum-epidermis, and epidermis-dermis, indicating successful transdermal and topical delivery. The in vitro cytotoxicity studies observed only minor cytotoxic effects on HaCaT cells, indicating the safety of the developed drug delivery systems. The investigation demonstrated promising results for the transdermal delivery of ibuprofen using the developed drug delivery systems, which contributes to valuable insights that may lead to improved pain management strategies.

Prokineticin System Is a Pharmacological Target to Counteract Pain and Its Comorbid Mood Alterations in an Osteoarthritis Murine Model

Osteoarthritis (OA) is the most prevalent joint disease associated with chronic pain. OA pain is often accompanied by mood disorders. We addressed the role of the Prokineticin (PK) system in pain and mood alterations in a mice OA model induced with monosodium iodoacetate (MIA). The effect of a PK antagonist (PC1) was compared to that of diclofenac. C57BL/6J male mice injected with MIA in the knee joint were characterized by allodynia, motor deficits, and fatigue. Twenty-eight days after MIA, in the knee joint, we measured high mRNA of PK2 and its receptor PKR1, pro-inflammatory cytokines, and MMP13. At the same time, in the sciatic nerve and spinal cord, we found increased levels of PK2, PKR1, IL-1β, and IL-6. These changes were in the presence of high GFAP and CD11b mRNA in the sciatic nerve and GFAP in the spinal cord. OA mice were also characterized by anxiety, depression, and neuroinflammation in the prefrontal cortex and hippocampus. In both stations, we found increased pro-inflammatory cytokines. In addition, PK upregulation and reactive astrogliosis in the hippocampus and microglia reactivity in the prefrontal cortex were detected. PC1 reduced joint inflammation and neuroinflammation in PNS and CNS and counteracted OA pain and emotional disturbances.

An application based on the analysis of thermograms to calculate the thermographic index for pain and swelling assessment

As the world's population ages, the prevalence of rheumatic diseases is increasing. These diseases are often diagnosed and monitored using imaging techniques such as infrared thermography. In this study, we developed an application to calculate the thermographic index (TI) in a series of thermograms. Such index is used in rheumatology as a complementary diagnostic tool to assess pain and swelling. We designed the application in MATLAB App Designer; an environment for creating applications with a graphical user interface. To evaluate the performance of the developed application, we calculated the TI of ten trigger points (anterior shoulder, sternum, posterior shoulder, upper back, lower back, elbow, lateral shoulder, elbow pit, knee, and back of the knee) in a series of thermal images from 37 healthy participants. Results of the average temperature varied between 31.35 (knee for women) and 33.92 (lateral shoulder for men) in °C and TIs were lower than 2 and the results in the knee region are consistent with those reported in previous studies due to only the TI in the knee is known. This study contributes to the literature with reference values for nine trigger points other than the knee. This app is easy to use and may be useful in future applications for disease detection or monitoring of its progression.

Modulating Effects of the Hydroethanolic Leaf Extract of Persicaria lanigera R. Br. Soják (Polygonaceae) against Acute Inflammation

Plant species have been used traditionally to treat numerous inflammatory disorders because of their known medicinal properties. This study aimed to assess the anti-inflammatory effect of aqueous ethanolic leaf extract of Persicaria lanigera using acute inflammatory models. The safety profile of the Persicaria lanigera extract was assessed using an acute toxicity model. The anti-inflammatory effect of the Persicaria lanigera leaf extract (100-600 mg·kg^-1, p.o.) was studied in carrageenan-induced paw oedema, zymosan-induced knee joint arthritis, and histamine-induced paw oedema in Sprague-Dawley rats (n = 5). It was observed that the Persicaria lanigera leaf extract administered prophylactically significantly inhibited paw oedema from 99.01 ± 12.59 to 59.10 ± 4.94%, 56.08 ± 3.65%, and 48.62 ± 3.27% at 100 mg·kg^-1, 300 mg·kg^-1, and 600 mg·kg^-1, while the standard drug, aspirin, showed 41.84 ± 9.25% in carrageenan-induced paw oedema, respectively. Furthermore, the extract decreased knee joint inflammation significantly from 62.43 ± 5.73% to 32.07 ± 2.98% and 24.33 ± 8.58% at 300 mg·kg^-1 and 600 mg·kg^-1 in zymosan-induced knee joint inflammation, respectively. In the histamine-induced paw oedema model, the extract significantly inhibited oedema to 61.53 ± 9.17%, 54.21 ± 9.38%, and 54.22 ± 9.37% at the same doses. Aqueous ethanolic leaf extract of Persicaria lanigera is safe and attenuates inflammation in acute inflammation models.

Palmitoyl-glucosamine co-micronized with curcumin for maintenance of meloxicam-induced pain relief in dogs with osteoarthritis pain

BACKGROUND

Osteoarthritis (OA) pain is the number one cause of chronic pain in dogs. Multimodal treatment, including combining safe and effective nutritional interventions with non-steroidal anti-inflammatory drugs (NSAIDs), is currently considered one of the most appropriate choices for managing OA pain. Palmitoyl-glucosamine is a feed material belonging to the ALIAmide family, whose parent molecule is the prohomeostatic lipid amide N-palmitoyl-ethanolamine. Curcumin is a promising plant antioxidant. The present study aimed at investigating whether 18-week dietary integration with palmitoyl-glucosamine co-micronized with curcumin was able to maintain pain relief in dogs with OA-associated chronic pain receiving meloxicam (1.5 mg/ml oral suspension) on a tapering regimen (progressive 25% decrease of the original 0.1 mg/kg/day dose, on a biweekly basis) during the first 8 weeks of treatment. Pain was assessed both by the owners and veterinary surgeons, with the first using both subjective evaluation and validated metrology instruments-i.e., Helsinki Chronic Pain Index (HCPI) and Canine Brief Pain Inventory (CBPI)-while the second rating the severity of lameness and pain on palpation on two previously used 5-point scales.

RESULTS

A total of fifty-eight dogs with OA chronic pain entered the uncontrolled study. Pain on HCPI was considered severe at baseline (range 18-39). Based on owner's assessment, 90% of dogs who responded to meloxicam at the full-dose regimen could reduce meloxicam up to 25% of the original dose without experiencing pain worsening. Moreover, 75% of dogs was assessed as having no pain increase ten weeks after meloxicam withdrawal. A statistically significant decrease of pain severity as scored by HCPI (P < 0.0001) was observed two and ten weeks after meloxicam withdrawal compared to study entry (17.0 ± 1.05 and 15.1 ± 1.02, respectively, vs 29.0 ± 0.74; mean ± SEM). After meloxicam withdrawal, no statistically significant change in the CBPI scores was recorded. Pain on palpation and lameness significantly changed to less severe distributions along the study period (P < 0.0001).

CONCLUSION

The findings appear to suggest that dietary integration with palmitoyl-glucosamine co-micronized with curcumin was able to maintain meloxicam-induced pain relief in dogs with severe OA chronic pain.

Overweight increases perioperative spinal surgery complications: a single-center retrospective study

BACKGROUND

The World Health Organization (WHO) defines a person with a body mass index (BMI) greater than or equal to 25 kg/m² as overweight. Being overweight is a lifestyle-related disease; however, little is known about the impact of overweight on the perioperative complications of orthopedic surgery. This study aimed to define the effect of overweight on the perioperative complications of spinal surgery.

METHODS

This retrospective case series study reviewed 269 consecutive patients who underwent spinal surgery. These patients were divided into the overweight (OW) and non-overweight (NOW) groups. Age, BMI, surgical time, blood loss, and perioperative complications were evaluated and compared between the groups.

RESULTS

There were 117 patients (43%) in the OW group and 152 (57%) in the NOW group. Cervical surgery was performed in 72 cases, thoracic surgery in 34, and lumbosacral surgery in 159. The surgical time was significantly longer in the OW group than in the NOW group (204.6 ± 98 min vs. 175 ± 75 min; p = 0.01). Blood loss was greater in the OW group than in the NOW group (446.8 ± 447.9 mL vs. 279 ± 296.5 mL; p = 0.00). Durotomy was more frequent in the OW group than in the NOW group (10 vs. 3 cases; p = 0.02). There was no difference in complications other than durotomy.

CONCLUSIONS

OW patients had longer surgical time, more blood loss, and more frequent durotomy than NOW patients. These findings indicate that overweight increases perioperative complications of spinal surgery.

The multifaceted role of mast cells in joint inflammation and arthritis

OBJECTIVE

To review current knowledge surrounding the role of mast cells in joint inflammation and arthritis.

METHOD

Narrative review.

RESULTS

Mast cells (MCs) are commonly observed in the synovium of the joint, particularly surrounding blood vessels and nerve endings. Some studies have reported increased MC number and degranulation in patients with osteoarthritis (OA). In two studies, MCs were the only immune cell type found in higher concentrations in synovium of OA patients compared to rheumatoid arthritis patients. Activation of MCs in OA includes signaling pathways such as immunoglobulin E/Fc epsilon Receptor 1 (IgE/FcεR1), immunoglobulin G/Fc gamma receptor (IgG/FcγR), complement, and toll-like cell surface receptor-mediated signaling, resulting in context-dependent release of either pro-inflammatory and/or anti-inflammatory mediators within the joint. Activation of MCs results in the release of pro-inflammatory mediators that ultimately contribute to inflammation of the synovium, bone remodeling, and cartilage damage. However, some studies have proposed that MCs can also exhibit anti-inflammatory effects by secreting mediators that inactivate pro-inflammatory cytokines such as interleukin 6 (IL-6).

CONCLUSIONS

MCs may play a role in mediating synovial inflammation and OA progression. However, the mechanisms governing MC activation, the downstream pro- and/or anti-inflammatory effects, and their impact on osteoarthritis pathogenesis remains to be elucidated and requires extensive further study. Furthermore, it is important to establish the pathways of MC activation in OA to determine whether MCs exhibit varying phenotypes as a function of disease stage. Ultimately, such research is needed before understanding whether MCs could be targeted in OA treatments.

Healthy lifestyles and wellbeing reduce neuroinflammation and prevent neurodegenerative and psychiatric disorders

Since the mid-20th century, Western societies have considered productivity and economic outcomes are more important than focusing on people's health and wellbeing. This focus has created lifestyles with high stress levels, associated with overconsumption of unhealthy foods and little exercise, which negatively affect people's lives, and subsequently lead to the development of pathologies, including neurodegenerative and psychiatric disorders. Prioritizing a healthy lifestyle to maintain wellbeing may slow the onset or reduce the severity of pathologies. It is a win-win for everyone; for societies and for individuals. A balanced lifestyle is increasingly being adopted globally, with many doctors encouraging meditation and prescribing non-pharmaceutical interventions to treat depression. In psychiatric and neurodegenerative disorders, the inflammatory response system of the brain (neuroinflammation) is activated. Many risks factors are now known to be linked to neuroinflammation such as stress, pollution, and a high saturated and trans fat diet. On the other hand, many studies have linked healthy habits and anti-inflammatory products with lower levels of neuroinflammation and a reduced risk of neurodegenerative and psychiatric disorders. Sharing risk and protective factors is critical so that individuals can make informed choices that promote positive aging throughout their lifespan. Most strategies to manage neurodegenerative diseases are palliative because neurodegeneration has been progressing silently for decades before symptoms appear. Here, we focus on preventing neurodegenerative diseases by adopting an integrated "healthy" lifestyle approach. This review summarizes the role of neuroinflammation on risk and protective factors of neurodegenerative and psychiatric disorders.

Comparative study on the topical and transdermal delivery of diclofenac incorporated in nano-emulsions, nano-emulgels, and a colloidal suspension

Transdermal delivery of active pharmaceutical ingredients (APIs) can be challenging, since the skin possesses a rate-limiting barrier, which may be overcome when APIs possess certain ideal physicochemical properties. The lack thereof would require that APIs be included in drug delivery vehicles to enhance skin permeation. Hence, diclofenac was incorporated into various drug delivery vehicles (i.e., nano-emulsions, nano-emulgels, and a colloidal suspension containing drug-loaded nanoparticles) to investigate the transdermal delivery thereof, while nano-emulsions and nano-emulgels had varying concentrations of evening primrose oil (EPO). The aim of the study was to compare the topical and transdermal diclofenac delivery from the different types of vehicles and to investigate the influence the different EPO concentrations had on diclofenac delivery. After characterization, membrane release studies were performed (to determine whether the API was successfully released from the vehicle) followed by in vitro skin diffusion studies and tape stripping (to establish whether the vehicles assisted the API in reaching the target site (transdermal delivery)). Lastly, cytotoxicity studies were conducted via methyl thiazolyl tetrazolium (MTT) and neutral red (NR) assays on human keratinocyte (HaCaT) cells. Results showed minimal cytotoxic effects at concentrations equivalent to that which had permeated through the skin, while the membrane release and in vitro skin diffusion studies indicated that the nano-emulsions and the 10% EPO vehicles increased API release and diffusion when compared to the other vehicles. However, the colloidal suspension had the highest concentrations of API within the skin. Hence, all the vehicles were non-toxic and effectively delivered diclofenac through the transdermal route.

Osteoarthritis Pain in Old Mice Aggravates Neuroinflammation and Frailty: The Positive Effect of Morphine Treatment

Knee osteoarthritis is a common cause of pain and disability in old subjects. Pain may predispose to the development of frailty. Studies on mechanisms underlying pain in osteoarthritis models during aging are lacking. In this work, we used the monosodium iodoacetate model of osteoarthritis in adult (11-week-old) and old (20-month-old) C57BL/6J mice to compare hypersensitivity, locomotion, neuroinflammation, and the effects of morphine treatment. After osteoarthritis induction in adult and old mice, weight-bearing asymmetry, mechanical allodynia, and thermal hyperalgesia similarly developed, while locomotion and frailty were more affected in old than in adult animals. When behavioral deficits were present, the animals were treated for 7 days with morphine. This opioid counteracts the behavioral alterations and the frailty index worsening both in adult and old mice. To address the mechanisms that underlie pain, we evaluated neuroinflammatory markers and proinflammatory cytokine expression in the sciatic nerve, DRGs, and spinal cord. Overexpression of cytokines and glia markers were present in osteoarthritis adult and old mice, but the activation was qualitatively and quantitatively more evident in aged mice. Morphine was able to counteract neuroinflammation in both age groups. We demonstrate that old mice are more vulnerable to pain's detrimental effects, but prompt treatment is successful at mitigating these effects.

Osteoarthritis: New Insight on Its Pathophysiology

Understanding of the basis of osteoarthritis (OA) has seen some interesting advancements in recent years. It has been observed that cartilage degeneration is preceded by subchondral bone lesions, suggesting a key role of this mechanism within the pathogenesis and progression of OA, as well as the formation of ectopic bone and osteophytes. Moreover, low-grade, chronic inflammation of the synovial lining has gained a central role in the definition of OA physiopathology, and central immunological mechanisms, innate but also adaptive, are now considered crucial in driving inflammation and tissue destruction. In addition, the role of neuroinflammation and central sensitization mechanisms as underlying causes of pain chronicity has been characterized. This has led to a renewed definition of OA, which is now intended as a complex multifactorial joint pathology caused by inflammatory and metabolic factors underlying joint damage. Since this evidence can directly affect the definition of the correct therapeutic approach to OA, an improved understanding of these pathophysiological mechanisms is fundamental. To this aim, this review provides an overview of the most updated evidence on OA pathogenesis; it presents the most recent insights on the pathophysiology of OA, describing the interplay between immunological and biochemical mechanisms proposed to drive inflammation and tissue destruction, as well as central sensitization mechanisms. Moreover, although the therapeutic implications consequent to the renewed definition of OA are beyond this review scope, some suggestions for intervention have been addressed.

Asiaticoside ameliorates osteoarthritis progression through activation of Nrf2/HO-1 and inhibition of the NF-κB pathway

Osteoarthritis has become the fourth cause of disability in the world and its occurrence and development are caused by apoptosis and extracellular matrix (ECM) degradation of chondrocytes. Asiaticoside (ASI) is a triterpene saponin compound obtained from Centella Asiatica and has anti-inflammatory and anti-apoptotic effects in various diseases. However, its effects on OA are not clear. In this study, we reported that ASI has a protective effect on the occurrence and progression of OA in vivo and in vitro, and demonstrated its potential molecular mechanism. In vitro, ASI treatment inhibited the release of pro-apoptotic factors induced by TBHP and promoted the release of the anti-apoptotic proteins. In addition, ASI promotes the expression of Aggrecan and Collagen II, while inhibiting the expression of thrombospondin motifs 5 (ADAMTS5) and matrix metalloproteinase-13 (MMP-13), which causes extracellular matrix (ECM) degradation. Mechanistically, ASI exerts its anti-apoptotic effect by activating the Nrf2/HO-1 pathway and preventing p65 from binding to DNA. Similarly, in vivo, ASI has been shown to have a protective effect in a mouse OA model. The conclusion is that our research shows that ASI can be used as a potential drug for the treatment of OA.

STRUCTURAL AND FUNCTIONAL CONDITION OF THE KNEE JOINT IN PATIENTS WITH MONOGONARTHROSIS IN THE STAGE OF EXACERBATION

The goal is to study the structural changes of the elements of the knee joint and their functional consequences in patients with monogonarthrosis of the 1st-2nd grade in the stage of exacerbation according to the data of a complex clinical and arthroscopic study. Materials and Methods. Materials - protocols of clinical, radiological and arthroscopic examination of 125 patients (54 (43.2%) men; 71 (57.8%) women), aged 18 - 79 years, with a previous diagnosis: Monoarthrosis of the knee joint in the stage of exacerbation. Research methods: questionnaire, orthopedic examination, X-ray diagnostics, arthroscopy, laboratory diagnostics of blood (determination of C-reactive protein (CRP) as a serological marker of inflammation), synovial fluid (analyses of physical properties, biochemical, cytological, bacteriological), statistical. Results and Discussion. According to the results of the comprehensive examination, the presence of primary monoarthrosis was confirmed in 118 (94.4%) patients (group A). Based on the definition of CRP, subgroups were distinguished: A1 (n=71; 56.8%) with a normal level and A2 (n=47; 37.6%) with elevated CRP. In 7 (5.6%) patients diagnosed seropositive unspecified rheumatoid monoarthritis with hypertrophic synovitis (group B). A significant predominance of women compared to men insubgroup A2 was revealed (p<0.05). It was investigated that the features of complaints, nature of pain sensations and indicators of orthopedic status in patients from subgroups A1 and A2 did not reliably differ in groups of patients with different levels of CRP. A significant predominance of normal contours of the affected knee joint was found in subgroups A1 (p<0.001) and A2 (p<0.01). Structural changes in knee joint elements according to X-ray and arthroscopic examination have no significant differences in subgroups of patients A1 and A2. Conclusions. The structural and functional state of the knee joints in patients with monogonarthrosis of the 1st-2nd grade according to the Kellgren-Lawrence classification is characterized by degenerative changes in almost all elements of the knee joint with moderate pain syndrome and functional disorders.

Mechanism of Glucose Water as a Neural Injection: A Perspective on Neuroinflammation

The entrapment of peripheral nerves is associated with chronic neuroinflammation and neuropathic pain, and perineural injection therapy with glucose is emerging as an effective treatment for peripheral entrapment neuropathy. However, the mechanism underlying the pharmacological effect of glucose on nerves remains unclear. One of the hypothesized mechanisms is that glucose reduces neurogenic inflammation. Therefore, we investigated the effects of high glucose concentrations on cytokine-induced neuroinflammation in vitro. Human SH-SY5Y neuronal cells were challenged with 10 ng/mL TNF-α for 16 h and subsequently treated with different glucose concentrations (0–25 mM) for 24 h. Cell viability was evaluated using the diphenyltetrazolium bromide assay, and proinflammatory cytokine levels were assessed using ELISA and quantitative PCR. In addition, mRNA levels of NF-κB and cyclooxygenase-2 were analyzed using quantitative PCR. Exposure to 10 ng/mL TNF-α resulted in decreased viability of SH-SY5Y cells and significant upregulation of IL-6, IL-1β, NF-κB, and cyclooxygenase-2. Subsequent exposure to high glucose levels (25 mM) markedly reduced the upregulation of IL-6, IL-1β, cyclooxygenase-2, and NF-κB, and restored the functional metabolism of SH-SY5Y cells, compared with that of the normal glucose control. Our findings suggest that high glucose concentrations can mitigate TNF-α-induced NF-κB activation, upregulation of proinflammatory cytokines, and metabolic dysfunction.

Reducing neuroinflammation via therapeutic compounds and lifestyle to prevent or delay progression of Parkinson's disease

Parkinson's disease (PD) is the second most common age-associated neurodegenerative disorder and is characterised by progressive loss of dopamine neurons in the substantia nigra. Peripheral immune cell infiltration and activation of microglia and astrocytes are observed in PD, a process called neuroinflammation. Neuroinflammation is a fundamental response to protect the brain but, when chronic, it triggers neuronal damage. In the last decade, central and peripheral inflammation were suggested to occur at the prodromal stage of PD, sustained throughout disease progression, and may play a significant role in the pathology. Understanding the pathological mechanisms of PD has been a high priority in research, primarily to find effective treatments once symptoms are present. Evidence indicates that early life exposure to neuroinflammation as a consequence of life events, environmental or behaviour factors such as exposure to infections, pollution or a high fat diet increase the risk of developing PD. Many studies show healthy habits and products that decrease neuroinflammation also reduce the risk of PD. Here, we aim to stimulate discussion about the role of neuroinflammation in PD onset and progression. We highlight that reducing neuroinflammation throughout the lifespan is critical for preventing idiopathic PD, and present epidemiological studies that detail risk and protective factors. It is possible that introducing lifestyle changes that reduce neuroinflammation at the time of PD diagnosis may slow symptom progression. Finally, we discuss compounds and therapeutics to treat the neuroinflammation associated with PD.

Identification of Synovial Fibroblast-Associated Neuropeptide Genes and m6A Factors in Rheumatoid Arthritis Using Single-Cell Analysis and Machine Learning

Objectives

Synovial fibroblasts (SFs) play an important role in the development and progression of rheumatoid arthritis (RA). However, the pathogenic mechanism of SFs remains unclear. The objective of this study was to investigate how neuropeptides and N6-methyladenosine (m6A) played an important role in the underlying pathogenic processes of SFs that contribute to the development of RA.

Methods

Single-cell RNA sequencing data were examined using single-cell analysis and machine learning. SF subgroups were identified based on the clustering and annotation results of the single-cell analysis. Moreover, cell–cell communication was used to analyse neuropeptide-related receptor and ligand pairs on the surface of SF cell membranes. Machine learning was used to explore the m6A factors acting on these neuropeptide genes.

Results

NPR3, GHR, BDKRB2, and CALCRL, four neuropeptide genes, were shown to be differently expressed among SF subgroups. Further investigation of receptor–ligand interactions found that NPR3 (in conjunction with NPPC, OSTN, NPPB, and NPPA) and GHR (in conjunction with GH1 and GH2) may have a role in SF interactions. As predicted by machine learning, IGFBP2 and METTL3 were identified as key factors regulating m6A of NPR3 and GHR. The expression levels and enrichment pathways of METTL3 and IGFBP2 were different among SF subgroups.

Conclusions

Single-cell analysis and machine learning efficiently identified neuropeptide genes and m6A factors that perform important regulatory functions in RA. Our strategy may provide a basis for future studies to identify pathogenic cell subpopulations and molecular mechanisms in RA and other diseases.

Infrared Thermography for the Evaluation of Inflammatory and Degenerative Joint Diseases: A Systematic Review

OBJECTIVE

Inflammation plays a central role in the pathophysiology of rheumatic diseases as well as in osteoarthritis. Temperature, which can be quantified using infrared thermography, provides information about the inflammatory component of joint diseases. This systematic review aims at assessing infrared thermography potential and limitations in these pathologies.

DESIGN

A systematic review was performed on 3 major databases: PubMed, Cochrane library, and Web of Science, on clinical reports of any level of evidence in English language, published from 1990 to May 2021, with infrared thermography used for diagnosis of osteoarthritis and rheumatic diseases, monitoring disease progression, or response to treatment. Relevant data were extracted, collected in a database, and analyzed for the purpose of this systematic review.

RESULTS

Of 718 screened articles 32 were found to be eligible for inclusion, for a total of 2094 patients. Nine studies reported the application to osteoarthritis, 21 to rheumatic diseases, 2 on both. The publication trend showed an increasing interest in the last decade. Seven studies investigated the correlation of temperature changes with osteoarthritis, 16 with rheumatic diseases, and 2 with both, whereas 2 focused on the pre-post evaluation to investigate treatment results in patients with osteoarthritis and 5 in patients with rheumatic diseases. A correlation was shown between thermal findings and disease presence and stage, as well as the clinical assessment of disease activity and response to treatment, supporting infrared thermography role in the study and management of rheumatic diseases and osteoarthritis.

CONCLUSIONS

The systematic literature review showed an increasing interest in this technology, with several applications in different joints affected by inflammatory and degenerative pathologies. Infrared thermography proved to be a simple, accurate, noninvasive, and radiation-free method, which could be used in addition to the currently available tools for screening, diagnosis, monitoring of disease progression, and response to medical treatment.

Anti-inflammatory activity of palmitoylethanolamide ameliorates osteoarthritis induced by monosodium iodoacetate in Sprague-Dawley rats

Novel treatment strategies are urgently required for osteoarthritis (OA). Palmitoylethanolamide (PEA) is a naturally occurring fatty acid amide with analgesic and anti-inflammatory effects. We aimed to examine its effect on OA and elucidate the molecular mechanism of actions in monosodium iodoacetate (MIA)-induced OA Sprague–Dawley rats. The experimental animals were divided into normal control group (injected with saline + treated with phosphate-buffered saline (PBS), NOR), control group (injected with MIA + treated with PBS, CON), 50 or 100 mg/kg body weight (BW)/day PEA-treated group (injected with MIA + treated with 50 or 100 mg of PEA/kg BW/day, PEA50 or PEA100), and positive control group (injected with MIA + treated with 6 mg of diclofenac/kg BW/day, DiC). The changes in blood parameters, body parameters, gene expression of inflammatory mediators and cytokines, knee thickness, and joint tissue were observed. Oral administration of PEA had no adverse effects on the BW, liver, or kidneys. PEA reduced knee joint swelling and cartilage degradation in MIA-induced OA rats. The serum levels of leukotriene B4, nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and prostaglandin E2 considerably reduced in the PEA100 group compared with those in the CON group. In the synovia of knee joints, the mRNA expression of iNOS, 5-Lox, Cox-2, Il-1β, Tnf-α, and Mmp-2, -3, -9, and -13 apparently increased with MIA administration. Meanwhile, Timp-1 mRNA expression apparently decreased in the CON group but increased to the normal level with PEA treatment. Thus, PEA can be an effective therapeutic agent for OA.

Pharmacologic agents directed at the treatment of pain associated with maladaptive neuronal plasticity

INTRODUCTION

The definition of nociplastic pain in 2016 has changed the way maladaptive chronic pain is viewed in that it may emerge without neural lesions or neural disease. Many endogenous and pharmacologic substances are being investigated for their role in treating the pain associated with neuronal plasticity.

AREAS COVERED

The authors review promising pharmacologic agents for the treatment of pain associated with maladaptive neuronal plasticity. The authors then provide the reader with their expert opinion and provide their perspectives for the future.

EXPERT OPINION

An imbalance between the amplification of ascending pain signals and the poor activation of descending inhibitory signals may be at the root of many chronic pain syndromes. The inhibitory activity of noradrenaline reuptake may play a role in neuropathic and nociplastic analgesia. A better understanding of the brain's pain matrix, its signaling cascades, and the complex bidirectional communication between the immune system and the nervous system may help meet the urgent and unmet medical need for safe, effective chronic pain treatment, particularly for pain with a neuropathic and/or nociplastic component.

The biological index of frailty: A new index for the assessment of frailty in human skeletal remains

OBJECTIVE

Frailty is the physiological stress that individuals suffer during their life. In past populations, frailty is conventionally assessed through the occurrence of different biomarkers of biological stress. Some efforts have been made to propose indexes that combine all biomarkers. However, these indices have some critical limitations: they cannot be used on incomplete skeletons, do not consider the severity and/or healing of lesions, and assign equal importance to different biomarkers. To address these limitations, we propose a new index to assess frailty in skeletal individuals.

MATERIAL AND METHODS

By statistically analyzing a large amount of osteological data available from the Museum of London, and using a Logit model, we were able to define a different weight for each reported biomarker of frailty, based on their importance in increasing the risk of premature death for the individuals.

RESULTS

The biological index of frailty (BIF) is the weighted mean of all biomarkers scored on the individuals, according to a different degree of importance assigned to each one. It also considers the severity and healing of the biomarkers when this is relevant to diagnose frailty. We applied BIF on a sample of Monastics and Non-Monastics from medieval England and compared it with the skeletal index of frailty (SFI).

DISCUSSION

BIF is the first frailty index that gives a different weight to each skeletal biomarker of stress, considers both severity and healing of the lesions, and can be applied on partial skeletal remains. The comparison with SFI showed that BIF is applicable to a larger number of skeletal individuals, revealing new differences between the Monastic and the Non-Monastic groups.

The Expanding Role of the COX Inhibitor/Opioid Receptor Agonist Combination in the Management of Pain

Pain management in both outpatient and inpatient settings demands a multidisciplinary approach entailing medical, physical and psychological therapies. Among these, multimodal analgesic regimens stand out as a promising treatment options. Cyclo-oxygenase (COX) inhibitor/opioid receptor agonist combinations hold great potential as effective pillars in the multimodal pain management by providing adequate analgesia with fewer safety risks due to COX inhibitors’ opioid-sparing effect. Thus, these combinations, either freely or in fixed-dose formulation, offer a feasible option for the prescribing clinicians who seek to maximise therapeutic effect while simultaneously minimise adverse effects. The selection of the appropriate non-steroidal anti-inflammatory drug (NSAID) and opioid agent at optimal doses is essential. It should be tailored to the patients’ analgesic necessities, and his/her gastrointestinal and cardiovascular risk, and potential concurrent aspirin use. Moreover, it should allow for addiction risk and the potential opioid-induced bowel dysfunction and constipation. To ensure an optimal match between the characteristics of the patient and the properties of the chosen medication, and to guide adequate and well-tolerated treatment decisions, it is of paramount importance to expand clinicians’ knowledge of the currently available COX inhibitor/opioid receptor agonist combinations. This invited narrative review deals with the literature evidence covering the components of multimodal opioid-sparing analgesic regimens. Also, it provides insights into the clinically relevant choice criteria to ensure a patient-tailored analgesia.

Unknown/enigmatic functions of extracellular ASC

Apoptosis-associated speck-like protein containing a caspase recruit domain (ASC), encoded by PYCARD gene, is a 22 kDa small molecule, which aggregates into ASC specks during inflammasome activation. ASC protein is an adaptor protein present in several inflammasome complexes that performs several intra- and extracellular functions, in monomeric form or as ASC specks, during physiological and pathological processes related to inflammation and adaptive immunity. Extracellular ASC specks (eASC specks) released during cell death by pyroptosis can contribute as a danger signal to the propagation of inflammation via phagocytosis and activation of surrounding cells. ASC specks are found in the circulation of patients with chronic inflammatory diseases and have been considered as relevant blood biomarkers of inflammation. eASC amplifies the inflammatory signal, may induce the production of autoantibodies, transports molecules that bind to this complex, contributing to the generation of antibodies, and can induce the maturation of cytokines promoting the modelling of the adaptive immunity. Although several advances have been registered in the last 21 years, there are numerous unknown or enigmatic gaps in the understanding of the role of eASC specks in the organism. Here, we provide an overview about the ASC protein focusing on the probable roles of eASC specks in several diseases, up to the most recent studies concerning COVID-19.

Bone marrow derived mast cells injected into the osteoarthritic knee joints of mice induced by sodium monoiodoacetate enhanced spontaneous pain through activation of PAR2 and action of extracellular ATP

Conditions that resemble osteoarthritis (OA) were produced by injection of sodium monoiodoacetate (MIA) into the knee joints of mice. Bone marrow derived mast cells (BMMCs) injected into the OA knee joints enhanced spontaneous pain. Since no spontaneous pain was observed when BMMCs were injected into the knee joints of control mice that had not been treated with MIA, BMMCs should be activated within the OA knee joints and release some pain-inducible factors. Protease activated receptor-2 (PAR2) antagonist (FSLLRY-NH₂) almost abolished the pain-enhancing effects of BMMCs injected into the OA knee joints, suggesting that tryptase, a mast cell protease that is capable of activating PAR2, should be released from the injected BMMCs and enhance pain through activation of PAR2. When PAR2 agonist (SLIGKV-NH₂) instead of BMMCs was injected into the OA knee joints, it was also enhanced pain. Apyrase, an ATP degrading enzyme, injected into the OA knee joints before BMMCs suppressed the pain enhanced by BMMCs. We showed that purinoceptors (P2X4 and P2X7) were expressed in BMMCs and that extracellular ATP stimulated the release of tryptase from BMMCs. These observations suggest that ATP may stimulate degranulation of BMMCs and thereby enhanced pain. BMMCs injected into the OA knee joints stimulated expression of IL-1β, IL-6, TNF-α, CCL2, and MMP9 genes in the infrapatellar fat pads, and PAR2 antagonist suppressed the stimulatory effects of BMMCs. Our study suggests that intermittent pain frequently observed in OA knee joints may be due, at least partly, to mast cells through activation of PAR2 and action of ATP, and that intraarticular injection of BMMCs into the OA knee joints may provide a useful experimental system for investigating molecular mechanisms by which pain is induced in OA knee joints.

Ultramicronized Palmitoylethanolamide (um-PEA): A New Possible Adjuvant Treatment in COVID-19 patients

The Coronavirus Disease-19 (COVID-19) pandemic has caused more than 100,000,000 cases of coronavirus infection in the world in just a year, of which there were 2 million deaths. Its clinical picture is characterized by pulmonary involvement that culminates, in the most severe cases, in acute respiratory distress syndrome (ARDS). However, COVID-19 affects other organs and systems, including cardiovascular, urinary, gastrointestinal, and nervous systems. Currently, unique-drug therapy is not supported by international guidelines. In this context, it is important to resort to adjuvant therapies in combination with traditional pharmacological treatments. Among natural bioactive compounds, palmitoylethanolamide (PEA) seems to have potentially beneficial effects. In fact, the Food and Drug Administration (FDA) authorized an ongoing clinical trial with ultramicronized (um)-PEA as an add-on therapy in the treatment of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. In support of this hypothesis, in vitro and in vivo studies have highlighted the immunomodulatory, anti-inflammatory, neuroprotective and pain-relieving effects of PEA, especially in its um form. The purpose of this review is to highlight the potential use of um-PEA as an adjuvant treatment in SARS-CoV-2 infection.

Chronic Pain in Dogs and Cats: Is There Place for Dietary Intervention with Micro-Palmitoylethanolamide?

The management of chronic pain is an integral challenge of small animal veterinary practitioners. Multiple pharmacological agents are usually employed to treat maladaptive pain including opiates, non-steroidal anti-inflammatory drugs, anticonvulsants, antidepressants, and others. In order to limit adverse effects and tolerance development, they are often combined with non-pharmacologic measures such as acupuncture and dietary interventions. Accumulating evidence suggests that non-neuronal cells such as mast cells and microglia play active roles in the pathogenesis of maladaptive pain. Accordingly, these cells are currently viewed as potential new targets for managing chronic pain. Palmitoylethanolamide is an endocannabinoid-like compound found in several food sources and considered a body's own analgesic. The receptor-dependent control of non-neuronal cells mediates the pain-relieving effect of palmitoylethanolamide. Accumulating evidence shows the anti-hyperalgesic effect of supplemented palmitoylethanolamide, especially in the micronized and co-micronized formulations (i.e., micro-palmitoylethanolamide), which allow for higher bioavailability. In the present paper, the role of non-neuronal cells in pain signaling is discussed and a large number of studies on the effect of palmitoylethanolamide in inflammatory and neuropathic chronic pain are reviewed. Overall, available evidence suggests that there is place for micro-palmitoylethanolamide in the dietary management of chronic pain in dogs and cats.

Pathophysiology of musculoskeletal pain: a narrative review

Musculoskeletal pain (excluding bone cancer pain) affects more than 30% of the global population and imposes an enormous burden on patients, families, and caregivers related to functional limitation, emotional distress, effects on mood, loss of independence, and reduced quality of life. The pathogenic mechanisms of musculoskeletal pain relate to the differential sensory innervation of bones, joints, and muscles as opposed to skin and involve a number of peripheral and central nervous system cells and mediators. The interplay of neurons and non-neural cells (e.g. glial, mesenchymal, and immune cells) amplifies and sensitizes pain signals in a manner that leads to cortical remodeling. Moreover, sex, age, mood, and social factors, together with beliefs, thoughts, and pain behaviors influence the way in which musculoskeletal pain manifests and is understood and assessed. The aim of this narrative review is to summarize the different pathogenic mechanisms underlying musculoskeletal pain and how these mechanisms interact to promote the transition from acute to chronic pain.

Endoscopic radiofrequency facet joint treatment in patients with low back pain: technique and long-term results. A prospective cohort study

Aims:

The aim of the study was to evaluate the efficacy of endoscopic rhizotomy (ER) for denervation of lumbar facet joints in patients with chronic low back pain (LBP) due to facet joint syndrome (FJS).

Methods:

A total of 50 consecutive patients suffering from chronic LBP due to facet joints were screened to be treated with ER. The patients participating in the study had a 2-year follow up. Numeric Rating Scale (NRS) and Oswestry Disability Index (ODI) were assessed in the preoperative and postoperative period. To evaluate secondary endpoints, patients were divided into groups. One group included the patients previously treated with percutaneous radiofrequency (RF). The other group comprised patients at their first interventional treatment. We also compared patients dividing them by age and by number of joints treated, trying to elucidate if these parameters could be predictive of effectiveness of the procedure.

Results:

All patients had a reduction in NRS and an improvement in ODI. NRS was reduced significantly after 1 month and remained the same until the end of the study. ODI was significantly improved from T1 (1 month after surgery) up to T7 (end of the study). The improvements did not differ whether already treated with percutaneous rhizotomy or not. Patients less than 60 years or with 1–2 joints treated had better improvement compared with the others.

Conclusion:

The results obtained demonstrate that ER for denervation of the facet joint is an effective treatment in patients with chronic LBP, with consistent and stable results at 2-year follow up. The technique has a rapid learning curve and no major complications occurred. Moreover, the previous percutaneous RF treatment had no influence on the results obtained with endoscopic technique. There is evidence that best results are obtained in younger patients and/or in patients with 1–2 joints treated.

Lay summary

Low-back pain has facet joints inflammation or degeneration as pain generator in 20–40% of cases. Nervous lesion of the dorsal ramus innervating the facet joints has been shown as an efficacious treatment to obtain good analgesia. Percutaneous techniques have provided short term results for several reasons. This research aimed to see whether endoscopic denervation, which guarantees a more precise approach to anatomical structure, would result in more durable results. The study conducted on 40 patients has made it clear that this approach gives significant analgesia for at least 2 years, which was the time of patient follow up.

Pain and Frailty in Hospitalized Older Adults

INTRODUCTION

Pain and frailty are prevalent conditions in the older population. Many chronic diseases are likely involved in their origin, and both have a negative impact on quality of life. However, few studies have analysed their association.

METHODS

In light of this knowledge gap, 3577 acutely hospitalized patients 65 years or older enrolled in the REPOSI register, an Italian network of internal medicine and geriatric hospital wards, were assessed to calculate the frailty index (FI). The impact of pain and some of its characteristics on the degree of frailty was evaluated using an ordinal logistic regression model after adjusting for age and gender.

RESULTS

The prevalence of pain was 24.7%, and among patients with pain, 42.9% was regarded as chronic pain. Chronic pain was associated with severe frailty (OR = 1.69, 95% CI 1.38-2.07). Somatic pain (OR = 1.59, 95% CI 1.23-2.07) and widespread pain (OR = 1.60, 95% CI 0.93-2.78) were associated with frailty. Osteoarthritis was the most common cause of chronic pain, diagnosed in 157 patients (33.5%). Polymyalgia, rheumatoid arthritis and other musculoskeletal diseases causing chronic pain were associated with a lower degree of frailty than osteoarthritis (OR = 0.49, 95%CI 0.28-0.85).

CONCLUSIONS

Chronic and somatic pain negatively affect the degree of frailty. The duration and type of pain, as well as the underlying diseases associated with chronic pain, should be evaluated to improve the hospital management of frail older people.

Pain and Frailty in Hospitalized Older Adults

INTRODUCTION

Pain and frailty are prevalent conditions in the older population. Many chronic diseases are likely involved in their origin, and both have a negative impact on quality of life. However, few studies have analysed their association.

METHODS

In light of this knowledge gap, 3577 acutely hospitalized patients 65 years or older enrolled in the REPOSI register, an Italian network of internal medicine and geriatric hospital wards, were assessed to calculate the frailty index (FI). The impact of pain and some of its characteristics on the degree of frailty was evaluated using an ordinal logistic regression model after adjusting for age and gender.

RESULTS

The prevalence of pain was 24.7%, and among patients with pain, 42.9% was regarded as chronic pain. Chronic pain was associated with severe frailty (OR = 1.69, 95% CI 1.38-2.07). Somatic pain (OR = 1.59, 95% CI 1.23-2.07) and widespread pain (OR = 1.60, 95% CI 0.93-2.78) were associated with frailty. Osteoarthritis was the most common cause of chronic pain, diagnosed in 157 patients (33.5%). Polymyalgia, rheumatoid arthritis and other musculoskeletal diseases causing chronic pain were associated with a lower degree of frailty than osteoarthritis (OR = 0.49, 95%CI 0.28-0.85).

CONCLUSIONS

Chronic and somatic pain negatively affect the degree of frailty. The duration and type of pain, as well as the underlying diseases associated with chronic pain, should be evaluated to improve the hospital management of frail older people.

Dietary Supplementation with Palmitoyl-Glucosamine Co-Micronized with Curcumin Relieves Osteoarthritis Pain and Benefits Joint Mobility

Simple Summary

Canine osteoarthritis is a chronic degenerative joint disease and a major cause of elective euthanasia. The disorder increasingly limits joint motion, might cause lameness as well as pain, and impacts quality of life. An unmet need remains for safe and effective therapies for osteoarthritis. Palmitoyl-glucosamine and curcumin are used in animal nutrition. A co-micronized formulation, with the two substances being jointly processed to reduce their particle size and increase the extent to which they can be absorbed, is currently available on the European market. The present study investigated if this formulation could relieve joint pain and benefit mobility. Two well-established rat models of inflammation and osteoarthritis pain were used. Results from the first set of experiments showed that the dietary supplement relieved experimentally induced paw edema, infiltration of inflammatory cells, and decreased sensitivity to painful stimuli (thermal hyperalgesia). In the osteoarthritis model, the supplement proved to protect joint cartilage against degradation and successfully address neuropathic pain (i.e., pain from normally non-painful stimuli). Locomotor function recovered by 45% under supplement administration. The present findings suggest that the dietary supplement with palmitoyl-glucosamine co-micronized with curcumin might help manage osteoarthritis.

Abstract

Chronic mixed pain and orthopedic dysfunction are the most frequently associated consequences of canine osteoarthritis (OA). An unmet need remains for safe and effective therapies for OA. Palmitoyl-glucosamine (PGA) and curcumin are safe and naturally occurring compounds whose use is limited by poor bioavailability. Micronization is an established technique to increase bioavailability. The aim of this study was to investigate if the dietary supplementation with PGA co-micronized with curcumin (PGA-Cur, 2:1 ratio by mass) could limit pathologic process in two well-established rat models of inflammation and OA pain, i.e., subplantar carrageenan (CAR) and knee injection of sodium monoiodoacetate (MIA), respectively. In CAR-injected animals, a single dose of PGA-cur significantly reduced paw edema and hyperalgesia, as well as tissue damage and neutrophil infiltration. The repeated administration of PGA-Cur three times per week for 21 days, starting the third day after MIA injection resulted in a significant anti-allodynic effect. Protection against cartilage damage and recovery of locomotor function by 45% were also recorded. Finally, PGA-cur significantly counteracted MIA-induced increase in serum levels of TNF-α, IL-1β, NGF, as well as metalloproteases 1, 3, and 9. All the effects of PGA-Cur were superior compared to the compounds used singly. PGA-Cur emerged as a useful dietary intervention for OA.

Sensory nerves protect from the progression of early stage osteoarthritis in mice

PURPOSE

Osteoarthritis (OA) is a chronic degenerative joint disease. Sensory nerves play an important role in bone metabolism and in the progression of inflammation. This study explored the effects of sensory nerve on OA progression at early stage in mice.

MATERIALS AND METHODS

OA was induced via destabilization of the medial meniscus (DMM) in C57BL/6 mice. Sensory denervation was induced by subcutaneous injection of capsaicin (90 mg/kg) one week prior to DMM. One week after capsaicin injection, sensory denervation in the tibia was confirmed by immunofluorescent staining. Four weeks after DMM, micro-CT scans, histological analysis, and RT-PCR tests were performed to evaluate OA progression.

RESULTS

Subcutaneous injection of capsaicin successfully induced sensory denervation in tibia. The Osteoarthritis Research Society International (OARSI) score and synovitis score of the capsaicin+DMM group were significantly higher than the score of the vehicle+DMM group. The BV/TV of the tibial subchondral bone in the capsaicin+DMM group was significantly lower than in the vehicle+DMM group. In addition, the level of expression of inflammatory factors in the capsaicin+DMM group was significantly higher than in the vehicle+DMM group.

CONCLUSIONS

Capsaicin-induced sensory denervation accelerated OA progression at early stage in mice. To put it another way, sensory nerve protects from OA progression at early stage in mice.

Inflammatory Cytokine-Producing Cells and Inflammation Markers in the Synovium of Osteoarthritis Patients Evidenced in Human Herpesvirus 7 Infection

A direct association between joint inflammation and the progression of osteoarthritis (OA) has been proposed, and synovitis is considered a powerful driver of the disease. Among infections implicated in the development of joint disease, human herpesvirus 7 (HHV-7) infection remains poorly characterized. Therefore, we assessed synovitis in OA patients; determined the occurrence and distribution of the HHV-7 antigen within the synovial membrane of OA-affected subjects; and correlated plasma levels of the pro-inflammatory cytokines tumor necrosis factor (TNF), interleukin-6 (IL-6), and TNF expressed locally within lesioned synovial tissues with HHV-7 observations, suggesting differences in persistent latent and active infection. Synovial HHV-7, CD4, CD68, and TNF antigens were detected immunohistochemically. The plasma levels of TNF and IL-6 were measured by an enzyme-linked immunosorbent assay. Our findings confirm the presence of persistent HHV-7 infection in 81.5% and reactivation in 20.5% of patients. In 35.2% of patients, virus-specific DNA was extracted from synovial membrane tissue samples. We evidenced the absence of histopathologically detectable synovitis and low-grade changes in the majority of OA patients enrolled in the study, in both HHV-7 PCR+ and HHV-7 PCR‒ groups. The number of synovial CD4-positive cells in the HHV-7 polymerase chain reaction (PCR)+ group was significantly higher than that in the HHV-7 PCR‒ group. CD4- and CD68-positive cells were differently distributed in both HHV-7 PCR+ and HHV-7 PCR‒ groups, as well as in latent and active HHV-7 infection. The number of TNF+ and HHV-7+ lymphocytes, as well as HHV-7+ vascular endothelial cells, was strongly correlated. Vascular endothelial cells, especially in the case of infection reactivation, appeared vulnerable. The balance between virus latency and reactivation is a long-term relationship between the host and infectious agent, and the immune system appears to be involved in displaying overreaction when a shift in the established equilibrium develops.

Knee Osteoarthritis: A Review of Pathogenesis and State-Of-The-Art Non-Operative Therapeutic Considerations

Being the most common musculoskeletal progressive condition, osteoarthritis is an interesting target for research. It is estimated that the prevalence of knee osteoarthritis (OA) among adults 60 years of age or older is approximately 10% in men and 13% in women, making knee OA one of the leading causes of disability in elderly population. Today, we know that osteoarthritis is not a disease characterized by loss of cartilage due to mechanical loading only, but a condition that affects all of the tissues in the joint, causing detectable changes in tissue architecture, its metabolism and function. All of these changes are mediated by a complex and not yet fully researched interplay of proinflammatory and anti-inflammatory cytokines, chemokines, growth factors and adipokines, all of which can be measured in the serum, synovium and histological samples, potentially serving as biomarkers of disease stage and progression. Another key aspect of disease progression is the epigenome that regulates all the genetic expression through DNA methylation, histone modifications, and mRNA interference. A lot of work has been put into developing non-surgical treatment options to slow down the natural course of osteoarthritis to postpone, or maybe even replace extensive surgeries such as total knee arthroplasty. At the moment, biological treatments such as platelet-rich plasma, bone marrow mesenchymal stem cells and autologous microfragmented adipose tissue containing stromal vascular fraction are ordinarily used. Furthermore, the latter two mentioned cell-based treatment options seem to be the only methods so far that increase the quality of cartilage in osteoarthritis patients. Yet, in the future, gene therapy could potentially become an option for orthopedic patients. In the following review, we summarized all of the latest and most important research in basic sciences, pathogenesis, and non-operative treatment.

Knee Osteoarthritis: A Review of Pathogenesis and State-Of-The-Art Non-Operative Therapeutic Considerations

Being the most common musculoskeletal progressive condition, osteoarthritis is an interesting target for research. It is estimated that the prevalence of knee osteoarthritis (OA) among adults 60 years of age or older is approximately 10% in men and 13% in women, making knee OA one of the leading causes of disability in elderly population. Today, we know that osteoarthritis is not a disease characterized by loss of cartilage due to mechanical loading only, but a condition that affects all of the tissues in the joint, causing detectable changes in tissue architecture, its metabolism and function. All of these changes are mediated by a complex and not yet fully researched interplay of proinflammatory and anti-inflammatory cytokines, chemokines, growth factors and adipokines, all of which can be measured in the serum, synovium and histological samples, potentially serving as biomarkers of disease stage and progression. Another key aspect of disease progression is the epigenome that regulates all the genetic expression through DNA methylation, histone modifications, and mRNA interference. A lot of work has been put into developing non-surgical treatment options to slow down the natural course of osteoarthritis to postpone, or maybe even replace extensive surgeries such as total knee arthroplasty. At the moment, biological treatments such as platelet-rich plasma, bone marrow mesenchymal stem cells and autologous microfragmented adipose tissue containing stromal vascular fraction are ordinarily used. Furthermore, the latter two mentioned cell-based treatment options seem to be the only methods so far that increase the quality of cartilage in osteoarthritis patients. Yet, in the future, gene therapy could potentially become an option for orthopedic patients. In the following review, we summarized all of the latest and most important research in basic sciences, pathogenesis, and non-operative treatment.

Nociceptin is present in synovial fluid of patients undergoing total knee arthroplasty

BACKGROUND

Osteoarthritis is a mechanical abnormality characterized by chronic joint pain associated with degeneration of the articular cartilage, synovitis, and local inflammation, leading to loss of function and pain. A connection exists between the peripheral nervous system and inflammatory joint degeneration. The process by which inflammation is influenced by the nervous system is known as neuroinflammation. One of the neuropeptides involved in peripheral neuroinflammation is nociceptin, a peptide related to the opioid class of substances. Nociceptin has both pro- and anti-inflammatory effects. Some studies show that nociceptin can be measured in synovial fluid, while other studies have not been able to detect it. The presence of nociceptin in synovial fluid could imply a molecular role for the neuropeptide in the joint, both physiologically as well as pathophysiologically. The goal of this pilot study was to determine whether nociceptin was present in the synovial fluid of osteoarthritic knees.

METHODS

Patients undergoing primary total knee arthroplasty were enrolled after Institutional Review Board approval was obtained. Synovial fluid was aspirated from patients' operative knee joints and blood samples were obtained. A commercially available enzyme Immunoassay kit was used to test for nociceptin. A linear mixed-effects model was developed to account for the repeated measurements and baseline covariates. Least squares (adjusted) means were derived from the model to compare the sample types and to compare subgroups.

RESULTS

Twenty patients were included in this study. Nociceptin was detected in the synovial fluid and plasma of all patients. The mean concentration (± standard deviation) of nociceptin in synovial fluid was 28.7 ± 18.2 pg/ml. The mean concentration of nociceptin in plasma was 45.2 ± 24.3 pg/ml pre-procedure, and 40.1 ± 20.6 pg/ml post-tourniquet deflation. The nociceptin concentration in synovial fluid was significantly lower than the nociceptin concentration in plasma, both pre-procedure and post-tourniquet deflation (p = 0.002 and p = 0.016 respectively). The nociceptin concentration in both plasma and synovial fluid was significantly lower in females versus males (p = 0.012).

CONCLUSION

We demonstrated that nociceptin is present in synovial fluid and plasma of patients undergoing total knee arthroplasty. This implies a potential role for nociceptin in modulating inflammation in osteoarthritis.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02528916 . Retrospectively registered on August 19, 2015.

Design, Synthesis, and Physicochemical and Pharmacological Profiling of 7-Hydroxy-5-oxopyrazolo[4,3-b]pyridine-6-carboxamide Derivatives with Antiosteoarthritic Activity In Vivo

The hallmark of joint diseases, such as osteoarthritis (OA), is pain, originating from both inflammatory and neuropathic components, and compounds able to modulate the signal transduction pathways of the cannabinoid type-2 receptor (CB2R) can represent a helpful option in the treatment of OA. In this perspective, a set of 18 cannabinoid type-2 receptor (CB2R) ligands was developed based on an unprecedented structure. With the aim of improving the physicochemical properties of previously reported 4-hydroxy-2-quinolone-3-carboxamides, a structural optimization program led to the discovery of isosteric 7-hydroxy-5-oxopyrazolo[4,3-b]pyridine-6-carboxamide derivatives. These new compounds are endowed with high affinity for the CB2R and moderate to good selectivity over the cannabinoid type-1 receptor (CB1R), associated with good physicochemical characteristics. As to the functional activity at the CB2R, compounds able to act either as agonists or as inverse agonists/antagonists were discovered. Among them, compound 51 emerged as a potent CB2R agonist able to reduce pain in rats carrying OA induced by injection of monoiodoacetic acid (MIA).

Attenuation of the Diffuse Noxious Inhibitory Controls in Chronic Joint Inflammatory Pain Is Accompanied by Anxiodepressive-Like Behaviors and Impairment of the Descending Noradrenergic Modulation

The noradrenergic system is paramount for controlling pain and emotions. We aimed at understanding the descending noradrenergic modulatory mechanisms in joint inflammatory pain and its correlation with the diffuse noxious inhibitory controls (DNICs) and with the onset of anxiodepressive behaviours. In the complete Freund's adjuvant rat model of Monoarthritis, nociceptive behaviors, DNICs, and anxiodepressive-like behaviors were evaluated. Spinal alpha2-adrenergic receptors (a2-AR), dopamine beta-hydroxylase (DBH), and noradrenaline were quantified concomitantly with a2-AR pharmacologic studies. The phosphorylated extracellular signal-regulated kinases 1 and 2 (pERK1/2) were quantified in the Locus coeruleus (LC), amygdala, and anterior cingulate cortex (ACC). DNIC was attenuated at 42 days of monoarthritis while present on days 7 and 28. On day 42, in contrast to day 28, noradrenaline was reduced and DBH labelling was increased. Moreover, spinal a2-AR were potentiated and no changes in a2-AR levels were observed. Additionally, at 42 days, the activation of ERKs1/2 was increased in the LC, ACC, and basolateral amygdala. This was accompanied by anxiety- and depressive-like behaviors, while at 28 days, only anxiety-like behaviors were observed. The data suggest DNIC is attenuated in prolonged chronic joint inflammatory pain, and this is accompanied by impairment of the descending noradrenergic modulation and anxiodepressive-like behaviors.

Endoscopic Neuromodulation of Suprascapular Nerve in Chronic Shoulder Pain: A Case Report

Shoulder pain is very frequent, especially in middle-aged male adults. Its treatment may be very problematic, mainly in patients who cannot rest and stop their work. At present, it is treated with analgesics, physiotherapy, infiltration of corticosteroids, and/or radiofrequency neuromodulation of the suprascapular nerve. This may be effective but not easy to do. Its efficacy is limited in time, especially because the approach to the nerve trunk may be problematic for its anatomical nature. Ultrasonography has helped, but it is not always completely helpful, due to the small dimension and the complexity of the anatomical structure. In this case report, we describe a more helpful approach to the nerve trunk using an endoscopic technique. The results are very promising. However, larger studies would be necessary to make clear its usefulness.

Pathophysiology and Therapeutic Perspectives of Oxidative Stress and Neurodegenerative Diseases: A Narrative Review

Introduction

Neurodegeneration is the term describing the death of neurons both in the central nervous system and periphery. When affecting the central nervous system, it is responsible for diseases like Alzheimer’s disease, Parkinson’s disease, Huntington’s disorders, amyotrophic lateral sclerosis, and other less frequent pathologies. There are several common pathophysiological elements that are shared in the neurodegenerative diseases. The common denominators are oxidative stress (OS) and inflammatory responses. Unluckily, these conditions are difficult to treat. Because of the burden caused by the progression of these diseases and the simultaneous lack of efficacious treatment, therapeutic approaches that could target the interception of development of the neurodegeneration are being widely investigated. This review aims to highlight the most recent proposed novelties, as most of the previous approaches have failed. Therefore, older approaches may currently be used by healthcare professionals and are not being presented.

Methods

This review was based on an electronic search of existing literature, using PubMed as primary source for important review articles, and important randomized clinical trials, published in the last 5 years. Reference lists from the most recent reviews, as well as additional sources of primary literature and references cited by relevant articles, were used.

Results

Eighteen natural pharmaceutical substances and 24 extracted or recombinant products, and artificial agents that can be used against OS, inflammation, and neurodegeneration were identified. After presenting the most common neurodegenerative diseases and mentioning some of the basic mechanisms that lead to neuronal loss, this paper presents up to date information that could encourage the development of better therapeutic strategies.

Conclusions

This review shares the new potential pharmaceutical and not pharmaceutical options that have been recently introduced regarding OS and inflammatory responses in neurodegenerative diseases.