Galvanic current activates the NLRP3 inflammasome to promote type I collagen production in tendon

The P2X7R/NLRP3 inflammasome axis suppresses enthesis regeneration through inflammatory and metabolic macrophage-stem cell cross-talk

The regeneration of the enthesis remains a formidable challenge in regenerative medicine. However, key regulators underlying unsatisfactory regeneration remain poorly understood. This study reveals that the purinergic receptor P2X7 (P2X7R)/Nod-like receptor family protein 3 (NLRP3) inflammasome axis suppresses enthesis regeneration by amplifying IL-1β-mediated inflammatory cross-talk and suppressing docosatrienoic acid (DTA) metabolic cross-talk. NLRP3 inflammasomes were activated in macrophages following enthesis injury, thereby impairing the histological and functional recovery of the injured enthesis. Single-cell RNA sequencing (scRNA-seq) indicated that Nlrp3 knockout attenuated pathological inflammation and ameliorated the detrimental effects of IL-1β signaling cross-talk. Furthermore, NLRP3 inflammasomes suppressed the secretion of anti-inflammatory cytokines (IL-10 and IL-13) and DTA. The NLRP3 inflammasome-mediated secretome reduced differentiation and migration of stem cells. Neutralizing IL-1β or replenishing docosatrienoic acid accelerated enthesis regeneration. Moreover, conditional knockout of P2rx7 in myeloid cells attenuated NLRP3 inflammasome activation and facilitated enthesis regeneration. This study demonstrates that the P2X7R/NLRP3 inflammasome axis represents a promising therapeutic target for enthesis repair.

Exploring molecular and cellular signaling pathways: Unraveling the pathogenesis of tendinopathy

Despite the long healing duration of tendon injuries, the outcomes of repairs are frequently suboptimal, resulting in persistent pain and reduced functionality. Current clinical approaches to tendinopathy are primarily symptomatic, encompassing nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroid injections, physical therapies, surgical interventions, loading programs, and pain management. Yet, these treatments have protracted timelines and their efficacy remains uncertain. This uncertainty stems largely from an incomplete understanding of tendinopathy's pathogenesis. Unraveling the mechanisms behind tendinopathy is essential for devising novel therapeutic strategies. In this context, this review systematic reviewed more recent cellular and molecular literature in tendinopathy, in order to summarize the up-to-date advancements including the structure and composition of healthy tendons, the pathophysiological changes in tendinopathy, the molecular pathways implicated in various forms of the condition, and current effective treatment methods. This review not only aims to offer insights but also to inspire further investigation into the mechanisms and clinical management of tendinopathy.

The translational potential of this article

A deficient understanding of the molecular mechanisms hampers the advancement of therapeutic strategies and drug development. Consequently, an in-depth examination of these molecular mechanisms is essential for comprehending the etiology of tendinopathy and for devising effective clinical management strategies.

The total electric charge and time of application of galvanic currents to macrophages can optimize the release of IL-1β with low cell death

Galvanic current has been emerging as a novel therapy to regenerate chronic tissue lesions, including musculoskeletal and dermatological lesions. Recently, the NLRP3 inflammasome and IL-1β release have been identified as a signaling pathway triggered upon galvanic current application. However, the parameters for the clinical application of galvanic current remain subjective to the experience of the facultative in charge. In this study we used an in vitro model of macrophage culture and application of different combinations of the parameters of galvanic current to study IL-1β production and cell death. Increasing electric charge of galvanic current induces the release of IL-1β, but electric charges equal or higher to 144 mC also increase cell death. The release of IL-1β have a substantial variation within different electric charge of galvanic currents, being increased by decreasing the current and increasing the time of current application. Within the range of current intensities studied, the most optimal protocol for maximizing IL-1β release without inducing cell death was identified at electric charges equal to or near 144 mC, applied over a total duration of approximately 25 s. Our findings lay the groundwork for future in vivo studies assessing different electric charge of galvanic current, with the aim of yielding clinically relevant outcomes.

Biological and Cellular Effects of Percutaneous Electrolysis: A Systematic Review

Background: Percutaneous electrolysis is an invasive physical therapy technique that is receiving attention. The objective of this article is to evaluate the biological and cellular effects of percutaneous electrolysis and its influence on tissue healing processes. Methods. The search strategy performed in PubMed, Cochrane Library, and Web of Sciences databases resulted in a total of 25 studies. Once inclusion and exclusion criteria were applied, seven studies were finally included in this systematic review. The biological effects of percutaneous electrolysis were evaluated and grouped into pro-inflammatory and anti-inflammatory effects, cell death, and extracellular matrix and tissue remodeling effects. Results. Percutaneous electrolysis generates a significant pro-inflammatory increase in the chronic tendon condition of IL1β-6-18-1α-1rn, NLRP3, and M1 polymorphonuclear cells and increased expression of COX2, TNFα, Cxcl10, and TGFβ1 during the first 7 days. This inflammation is regulated as of day 13. A significant increase in cell death markers, such as LDH, Yo-Pro, cytochrome C, and Smac/Diablo markers, was observed during the first 7 days. Finally, a significant increase in markers Mmp9, VEGF, VEGFR, PPAR-γ/tubulin, and COL-I was observed in the extracellular matrix and tissue remodeling, and a decrease in COL-III was observed during the first 7 days. In the acute inflammatory injury condition, an increase in anti-inflammatory markers, such as IL-10-13, CCL1, and IkB, and a significant decrease in pro-inflammatory cytokines, such as IL-6-1β, CCL3-4-5, CCR5-8, NFkB, and TNFα, were observed during the first 7 days. Finally, a significant increase in VEGF, VEGFR, and PPAR-γ/tubulin markers in the extracellular matrix and tissue remodeling was observed for this condition during the first 7 days. Conclusions. Percutaneous electrolysis generates a controlled local pro-inflammatory effect in chronic conditions and regulates inflammation in inflammatory injuries (during the first 7 days). Electrolysis has short-term effects (0-7 days post) of cell death and controlled extracellular matrix destruction. Additionally, it facilitates subsequent healing by improving extracellular matrix synthesis starting from 7 days after application.

Multiple ASC-dependent inflammasomes drive differential pro-inflammatory cytokine production in a mouse model of tendinopathy

Inflammasomes are multiprotein complexes that regulate the bioactive production of IL-1β and IL-18, being implicated in the inflammatory response of different diseases. The inflammasome formed by the cytosolic sensor NLRP3 is highly promiscuous, as it could be activated by different pathogen- and sterile-signals. However, few models have studied the implication of NLRP3 in tissue damage-induced inflammation, particularly the implication of NLRP3 in tendinopathies. Here, we aimed to investigate the implication of NLRP3 in a mouse model of tendinopathy by collagenase degradation of the extracellular matrix in the Achilles' mice tendon. We found that NLRP3 was involved in the production of IL-1β, but another ASC-dependent inflammasome was required to produce IL-18 during sterile tissue damage. Our study suggests that in the immune response to extracellular matrix degradation different inflammasomes, probably expressed in different cell compartments, were able to differentially control IL-1β and IL-18 production in vivo. These results suggest the potential use of therapies targeting ASC as beneficial in the treatment of tendinopathies.

Pulsed negative pressure myofascial vacuum therapy and percutaneous electrolysis in the treatment of lateral epicondylalgia: A single-blind randomized controlled trial

BACKGROUND

Lateral Epicondylalgia (LE) represents one of the most common injuries of the upper limb. It is necessary to find effective treatments that reduce pain and increase functionality.

PURPOSE

To determine the effects of an integrated intervention of Pulsed Negative Pressure Myofascial Vacuum Therapy (VT), Percutaneous Electrolysis (PE) and eccentric exercise (EE) in the treatment of LE compared versus Manual Therapy soft tissue mobilization (MT) and Ultrasound therapy (US) and EE.

STUDY DESIGN

Single-blind randomized controlled trial.

METHODS

Forty participants, with unilateral LE, were randomly divided into two groups: VT + PE + EE group (n = 20) and MT + US + EE group (n = 20). The VT + PE + EE group received one weekly session for four weeks and a regimen of EE daily at-home, and the MT + US + EE group received 10 sessions over a period of two weeks and a regimen of EE daily at-home. Numerical pain rating scale (NPRS), range of motion (ROM) pressure pain threshold (PPT) and function (PRTEE questionnaire) were measured before treatment, at the end of treatment, and at one- and three-month follow-ups.

RESULTS

The statistically significant improvements were found post-treatment, favoring the VT + PE group in pain intensity (p < 0.001; ES = 0.408), PRTEE-S Pain (p = 0.001; ES = 0.377), PRTEE-S Specific function (p = 0.004; ES = 0.306) and PRTEE-S Total (p = 0.001; ES = 0.355). The VT + PE + EE treatment showed greater effectiveness than the MT + US + EE treatment at immediate post-treatment, as well as at the one-month and three-months follow-up.

CONCLUSIONS

VT and PE added to an EE program could be an effective treatment for pain, ROM, PPT, and function in patients with LE.

Pleiotropic role of endoplasmic reticulum stress in the protection of psoralidin against sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a severe complication that affects the central nervous system and is a leading cause of increased morbidity and mortality in intensive care units. Psoralidin (PSO), a coumarin compound isolated from the traditional Chinese medicine Psoralea corylifolia L., can penetrate the blood-brain barrier and has various pharmacological activities, including anti-inflammation, anti-oxidation and anti-depression. This study aims to explore whether PSO alleviates SAE and delve into the underlying mechanisms. We found that PSO treatment significantly reduced sepsis scores, aspartate transaminase (AST) and aspartate transaminase (LDH), while increased anal temperature and neurological scores in CLP-injured mice. Moreover, PSO treatment ameliorated sepsis-associated cognitive impairment, mood, anxiety disorders, inhibited inflammatory responses, as well as attenuated endoplasmic reticulum stress (ERS). These results were also validated in vitro experiments, PSO treatment reduced ROS, inflammation response, and attenuated ERS in LPS-injured N2a cells. Importantly, tunicamycin (TUN), as ERS agonist, significantly reversed the protective effect of PSO on LPS-injured N2a cells, as evidenced by increased expression levels of IL-6, NLRP3, CHOP, and ATF6. Likewise, ATF6 overexpression also reversed the protective effect of PSO. In conclusion, these results confirmed that PSO has a protective effect on SAE, which was largely attributed to neuroinflammation and ERS. These findings provide new insights into the neuroprotective role of PSO and suggest that PSO is a new therapeutic intervention of SAE.

New Ultrasound-Guided Approach to Access to the Posterolateral Part of Intervertebral Lumbar Discs: A Cadaveric Study

Background: Approximately 40% of chronic low back pain patients have a discogenic origin. In relation to intervertebral disc injuries, most of them are in the posterior and lateral zone of the disc, involving the anterior lumbar roots and the spinal cord. Objective: The objective was to analyze and describe the accuracy and safety of a new ultrasound-guided approach to target the posterolateral part of the intervertebral lumbar discs in cadaveric specimens. Methods: A cross-anatomical study on sixty cadaver intervertebral lumbar discs was performed. A needle was introduced in the posterolateral part of the discs using ultrasound guidance. A transducer was placed in the anterior abdomen to visualize the discs in cross-section as well. A dissection of the specimen was performed to visualize the final position of the needle tip and its distance from the main lumbar structures. The angulation, length, and distance of the needle from the vertebral spine, the relevant ultrasound anatomical references, and the accuracy of the procedure were evaluated. Results: The needle tip reached the posterolateral part of the discs in 93.3% of the attempts. The mean length of the needle inserted was 79 ± 15 mm, the angulation 129 ± 20.2°, the distance from the spinous process was 77 ± 19 mm, and the distance of the needle to the nerve roots was 2.0 ± 1.2 mm. No statistically significant differences between genders were found. Conclusions: An ultrasound-guided technique can be an accurate and safe technique to perform invasive procedures on the posterolateral part of the intervertebral lumbar discs.

Safety and Effectiveness of Percutaneous Ultrasound-Guided Galvanic Current in Tunnels of Patients with Hidradenitis Suppurativa: A Pilot Study

INTRODUCTION

The recurrent nature of hidradenitis suppurativa (HS), even under maintained systemic treatment, makes it necessary to have effective local treatments; however, the response to these therapies is variable (44-81%). The application of galvanic current (GC) has demonstrated its utility in humans in treating lesions structurally similar to those of HS. With this background, the main objective of this study was to evaluate the efficacy and safety of ultrasound-guided percutaneous GC in inflamed and/or draining tunnels of HS.

METHODS

This was an open study (one-way repeated measures design over time). Patients were evaluated at 4 and 12 weeks after receiving GC. A combined clinical response at week 12 (absence of suppuration/inflammation on examination and clinical interview) was considered the principal variable of efficacy. Adverse effects potentially associated with GC were reported by telephone and at each visit.

RESULTS

Twenty-six patients were included, with a male/female ratio of 5:8. The mean age was 35.84 (13.14) years. At 12 weeks after the administration of GC, a complete response was achieved in 77% (20/26) of the treated lesions. No serious adverse effects were observed, and the mean procedural pain assessed by the numeric rating scale was 0.03 (0.2).

CONCLUSION

GC has proven to be effective and well tolerated in inflamed and draining tunnels of patients with HS.

Structural and Functional Changes in Supraspinatus Tendinopathy through Percutaneous Electrolysis, Percutaneous Peripheral Nerve Stimulation and Eccentric Exercise Combined Therapy: A Single-Blinded Randomized Clinical Trial

Shoulder tendinopathies produce pain and reduce functionality. The aim of this randomized clinical trial was to analyze the effects of Percutaneous electrolysis (PE), Percutaneous peripheral Nerve Stimulation (PNS) and eccentric exercise (EE) on pain (NPRS), strength, electromyographic activity, ultrasound characteristics of the tendon (echogenicity, thickness and hypervascularization) and functionality (DASH and SPADI) in individuals with supraspinatus tendinopathy. Participants (n = 50) were divided into two groups; they received 4 treatment sessions, 1 per week, of PE and PNS (n = 25) or 10 treatment sessions of TENS and US (n = 25). Both groups performed the EE program consisting of 3 sets of 10 repetitions of each of the 3 exercises, twice a day, during the 4 weeks. Follow-up was carried out at 4, 12 and 24 weeks after the start of the intervention. There are statistically significant differences in the analysis between groups (p < 0.001) in the post-treatment and follow-up measurements favorable to the PE+PNS+EE treatment on pain (NPRS), strength, supraspinatus electromyographic amplitude, ultrasound characteristics of the tendon (echogenicity, thickness and hypervascularization) and DASH and SPADI questionnaires. The combined treatment with PE, PNS and EE is an effective option in the clinical management of tendinopathies, with positive results in the short and long term on the variables studied.

Protective action of ultrasound-guided electrolysis technique on the muscle damage induced by notexin in rats

It is known that exercise can be one of the causes of muscular damage. In recent times, physiotherapists and medical professionals have been employing USGET techniques to stimulate muscle recovery to improve its performance after the injury. We pretend to analyse if the Ultrasound-guided electrolysis (USGET) technique could reduce muscle damage, inflammation, and pain in the present study. Female Wistar rats were assigned to one of three different groups: control (C), notexin (NOT) and notexin with USGET (electrolysis at 6mA) (NOT+USGET). We used the USGT technique, based on electrical stimulation with a continuous current of 4 pulses at an intensity of 6 mA for 5 seconds, conveyed to the muscle. The response was tested with motor function tests. In these tests, we could observe an increase in time and foot faults when crossing a beam in the NOT group compared to C group rats. On the other hand, a significant decrease in both variables was detected in the NOT+USGET compared to the NOT group. Muscle power was measured with a grip strength test, obtaining far better performances in NOT+USGET rats when compared to NOT rats. Moreover, the USGET technique prevented the increase of pro-inflammatory proteins IL-6 and chemokines CCL3 (Chemokine (C-C motif) ligand 3), CCL4 (Chemokine (C-C motif) ligand 4), and CCL5 (Chemokine (C-C motif) ligand 5) with their receptor CCR5 (C-C chemokine receptor type 5), induced by notexin in the quadriceps. At the same time, the study evidenced a decrease in both CCR8 (C-C chemokine receptor type 5,) and NF-ᴋB (nuclear factor- ᴋB) expressions after USGET treatment. On the other hand, we obtained evidence that demonstrated anti-inflammatory properties of the USGET technique, thus being the increase in IL-10 (Interleukin 10) and IL-13 (Interleukin 13) in the NOT+USGET group compared to the NOT group. Furthermore, when applying NSGET after damage, an increase in anti-inflammatory mediators and reduction of pro-inflammatory mediators, which, overall, promoted muscle regeneration, was observed. These results support the idea that the NSGET technique improves muscle recovery after toxic damages, which would justify its employment.

Application of Percutaneous Needle Electrolysis Does Not Elicit Temperature Changes: An In Vitro Cadaveric Study

Percutaneous needle electrolysis (PNE) consists of the ultrasound-guided application of a galvanic electrical current through a solid filament needle. One proposed therapeutic mechanism for this intervention is a potential thermal effect. The aim of this study was to investigate if the application of PNE induces changes in temperature in different cadaveric musculoskeletal tissues. A repeated measure experimental cadaveric study was designed with 10 cryopreserved knees (5 men, 5 women). Sterile stainless-steel needles of 40 mm length and 0.30 mm caliber were used in this study. An ultrasound-guided needling puncture was performed in the targeted tissue (patellar tendon, infra-patellar fat, and vastus medialis muscle). Additionally, the tip of the needle was placed next to the thermometer sensor at the minimum possible distance without direct contact with it. The temperature differences before and after different applications were measured. The applications were: three applications for 3 s of 3 mA of intensity (3:3:3) when the tendon was the targeted tissue, three applications for 3 s of 1.5 mA of intensity (1.5:3:3) when the fat or muscle was the targeted tissue, and 24 s of 1 mA of intensity (1:24:1) in all tissues. No statistically significant Group*Time interactions were found in any tissue (tendon: F = 0.571, p = 0.459, ŋ2 = 0.03; fat pad: F = 0.093; p = 0.764, ŋ2 = 0.01; muscle: F = 0.681; p = 0.420, ŋ2 = 0.04). Overall, no changes in temperature were observed between both applications in the tendon (3:3:3 vs. 1:24:1) and fat/muscle (1.5:3:3 vs. 1:24:1) tissues. The application of two different percutaneous needle electrolysis protocols did not produce appreciable thermal changes in the tendon, fat, and muscle tissues of human cadavers. The results from the current cadaver study support that a thermal effect should not be considered as a mechanism of clinical action regardless of the targeted human tissue when applying percutaneous needle electrolysis since no changes in temperature after its application were observed.

Focus on the Role of the NLRP3 Inflammasome in Multiple Sclerosis: Pathogenesis, Diagnosis, and Therapeutics

Neuroinflammation is initiated with an aberrant innate immune response in the central nervous system (CNS) and is involved in many neurological diseases. Inflammasomes are intracellular multiprotein complexes that can be used as platforms to induce the maturation and secretion of proinflammatory cytokines and pyroptosis, thus playing a pivotal role in neuroinflammation. Among the inflammasomes, the nucleotide-binding oligomerization domain-, leucine-rich repeat- and pyrin domain-containing 3 (NLRP3) inflammasome is well-characterized and contributes to many neurological diseases, such as multiple sclerosis (MS), Alzheimer's disease (AD), and ischemic stroke. MS is a chronic autoimmune disease of the CNS, and its hallmarks include chronic inflammation, demyelination, and neurodegeneration. Studies have demonstrated a relationship between MS and the NLRP3 inflammasome. To date, the pathogenesis of MS is not fully understood, and clinical studies on novel therapies are still underway. Here, we review the activation mechanism of the NLRP3 inflammasome, its role in MS, and therapies targeting related molecules, which may be beneficial in MS.