Conjugation with Methylsulfonylmethane Improves Hyaluronic Acid Anti-Inflammatory Activity in a Hydrogen Peroxide-Exposed Tenocyte Culture In Vitro Model

Hypoxia-Inducible Factor and Oxidative Stress in Tendon Degeneration: A Molecular Perspective

Tendinopathy is a debilitating condition marked by degenerative changes in the tendons. Its complex pathophysiology involves intrinsic, extrinsic, and physiological factors. While its intrinsic and extrinsic factors have been extensively studied, the role of physiological factors, such as hypoxia and oxidative stress, remains largely unexplored. This review article delves into the contribution of hypoxia-associated genes and oxidative-stress-related factors to tendon degeneration, offering insights into potential therapeutic strategies. The unique aspect of this study lies in its pathway-based evidence, which sheds light on how these factors can be targeted to enhance overall tendon health.

Clinical effects of sodium hyaluronate combined with platelet-rich plasma injection on rotator cuff injury in arthroscopic repair

Objective

Rotator cuff injury is one prevalent shoulder condition that often leads to pain and dysfunction. The study explored the clinical effects of sodium hyaluronate combined with platelet-rich plasma (PRP) injection on rotator cuff injury in arthroscopic repair.

Methods

A total of 92 cases with rotator cuff injury were randomly divided into the control group (n = 46, treated with shoulder arthroscopy repair combined with subacromial space injection of sodium hyaluronate) and the experimental group (n = 46, treated with subacromial space injection of autologous PRP on the basis of the treatment in the control group). Visual analogue scale (VAS), Constant-Murley scale (CMS), University of California, Los Angeles (UCLA), American Shoulder and Elbow Society (ASES), and quality of life (QOL) scores, as well as complications were compared in the two groups before surgery and at 3 and 6 months after surgery. Shoulder range of motion (ROM) was measured before and after surgery.

Results

VAS scores of patients in the two groups at 3 and 6 months after surgery were lower than those before surgery, and the VAS scores of patients in the experimental group at 3 and 6 months after surgery were much lower than those in the control group (all P < 0.05). The scores of CMS, UCLA, ASES, and QOL, and shoulder ROM in both groups at 3 and 6 months after surgery were higher than those before surgery, and these shoulder joint function scores, QOL and shoulder ROM in the experimental group at 3 and 6 months after surgery were higher than those in the control group (all P < 0.05). No statistically significant difference presented in the incidence of complications between the two groups (P > 0.05).

Conclusion

Arthroscopic rotator cuff repair and sodium hyaluronate combined with PRP injection can effectively reduce pain symptoms, improve shoulder joint function and shoulder ROM, and improve QOL in patients with rotator cuff injury.

Inhibitory effect of taurine on rotator cuff degeneration via mitochondrial protection

OBJECTIVES

Degenerative rotator cuff tears do not heal spontaneously, necessitating surgical intervention. This makes prevention crucial, but effective prophylactic measures are currently lacking. Oxidative stress has recently been implicated as a cause of degenerative rotator cuff tears, while mitochondrial injury has been reported in the development of age-related rotator cuff degeneration. Taurine, which has antioxidant properties, has been found to be effective in the treatment of various mitochondrial abnormalities. This prompted us to investigate the inhibitory effect of taurine and some other antioxidants against rotator cuff degeneration using tenocytes.

METHODS

Hydrogen peroxide (H₂O₂, 2 mM) was added to tenocytes in medium with 0.8 µM taurine (Group TAU), medium with 100 µM α-tocopherol (Group E), and medium with 150 µM ascorbic acid (Group C), then each medium was cultured for 24 h. Tenocytes supplemented with 2 mM H₂O₂ alone were similarly cultured for 24 h (Group H₂O₂). In each group, immunostaining was performed for the oxidative stress marker 8-hydroxy-2'-deoxyguanosine and advanced glycation end products (AGE), which contribute to the development of age-related rotator cuff degeneration. In addition, levels of reactive oxygen species were measured using a cell-based assay kit, and results were compared. Immunostaining was also performed for indices of apoptosis (caspase-9, cleaved caspase-3 and Bcl-2), and Western blotting was used to quantify activation of caspase-9 at an early stage in each group.

RESULTS

Oxidative stress and AGE levels were decreased in the E and C groups. Levels of all parameters were reduced in the TAU group.

CONCLUSIONS

Taurine showed preventative effects against rotator cuff degeneration. The simple method of administration and paucity of side effects make clinical application easy, and the clear potential as a novel prophylactic strategy against degenerative rotator cuff tear warrants further study.

Roles of Oxidative Stress in Acute Tendon Injury and Degenerative Tendinopathy-A Target for Intervention

Both acute and chronic tendon injuries are disabling sports medicine problems with no effective treatment at present. Sustained oxidative stress has been suggested as the major factor contributing to fibrosis and adhesion after acute tendon injury as well as pathological changes of degenerative tendinopathy. Numerous in vitro and in vivo studies have shown that the inhibition of oxidative stress can promote the tenogenic differentiation of tendon stem/progenitor cells, reduce tissue fibrosis and augment tendon repair. This review aims to systematically review the literature and summarize the clinical and pre-clinical evidence about the potential relationship of oxidative stress and tendon disorders. The literature in PubMed was searched using appropriate keywords. A total of 81 original pre-clinical and clinical articles directly related to the effects of oxidative stress and the activators or inhibitors of oxidative stress on the tendon were reviewed and included in this review article. The potential sources and mechanisms of oxidative stress in these debilitating tendon disorders is summarized. The anti-oxidative therapies that have been examined in the clinical and pre-clinical settings to reduce tendon fibrosis and adhesion or promote healing in tendinopathy are reviewed. The future research direction is also discussed.

Methylsulfonylmethane ameliorates inflammation via NF-κB and ERK/JNK-MAPK signaling pathway in chicken trachea and HD11 cells during Mycoplasma gallisepticum infection

Mycoplasma gallisepticum (MG) is an avian pathogen that commonly causes respiratory diseases in poultry. Methylsulfonylmethane (MSM) is a sulfur-containing natural compound that could alleviate inflammatory injury through its excellent anti-inflammatory and antioxidant properties. However, it is still unclear whether MSM prevents MG infection. The purpose of this study is to determine whether MSM has mitigative effects on MG-induced inflammatory injury in chicken and chicken like macrophages (HD11 cells). In this research, White Leghorn chickens and HD11 cells were used to build the MG-infection model. Besides, the protective effects of MSM against MG infection were evaluated by detecting MG colonization, histopathological changes, oxidative stress and inflammatory injury of trachea, and HD11 cells. The results revealed that MG infection induced inflammatory injury and oxidative stress in trachea and HD11 cells. However, MSM treatment significantly ameliorated oxidative stress, partially alleviated the abnormal morphological changes and reduced MG colonization under MG infection. Moreover, MSM reduced the mRNA expression of proinflammatory cytokines-related genes and decreased the number of death cells under MG infection. Importantly, the protective effects of MSM were associated with suppression of nuclear factor-kappa B (NF-κB) and extracellular signal-related kinases (ERK)/Jun amino terminal kinases (JNK)-mitogen-activated protein kinases (MAPK) pathway in trachea and HD11 cells. These results proved that MSM has protective effects on MG-induced inflammation in chicken, and supplied a better strategy for the protective intervention of this disease.

A Novel Class of Dual-Acting DCH-CORMs Counteracts Oxidative Stress-Induced Inflammation in Human Primary Tenocytes

Carbon monoxide (CO) can prevent cell and tissue damage by restoring redox homeostasis and counteracting inflammation. CO-releasing molecules (CORMs) can release a controlled amount of CO to cells and are emerging as a safer therapeutic alternative to delivery of CO in vivo. Sustained oxidative stress and inflammation can cause chronic pain and disability in tendon-related diseases, whose therapeutic management is still a challenge. In this light, we developed three small subsets of 1,5-diarylpyrrole and pyrazole dicobalt(0)hexacarbonyl (DCH)-CORMs to assess their potential use in musculoskeletal diseases. A myoglobin-based spectrophotometric assay showed that these CORMs act as slow and efficient CO-releasers. Five selected compounds were then tested on human primary-derived tenocytes before and after hydrogen peroxide stimulation to assess their efficacy in restoring cell redox homeostasis and counteracting inflammation in terms of PGE₂ secretion. The obtained results showed an improvement in tendon homeostasis and a cytoprotective effect, reflecting their activity as CO-releasers, and a reduction of PGE₂ secretion. As these compounds contain structural fragments of COX-2 selective inhibitors, we hypothesized that such a composite mechanism of action results from the combination of CO-release and COX-2 inhibition and that these compounds might have a potential role as dual-acting therapeutic agents in tendon-derived diseases.

Understanding collagen interactions and their targeted regulation by novel drugs

Introduction: Among protein and fibers in the extracellular matrix (ECM), collagen is the most copious and widely employed in cosmetic, food, pharmaceutical, and biomedical industries due to its extensive biocompatible and versatile properties. In the last years, the knowledge about functions of collagens increased and expanded dramatically. Once considered only crucial for the ECM scaffolding and mechanotransduction, additional functional roles have now been ascribed to the collagen superfamily which are defined by other recently discovered domains, supramolecular assembly and receptors.Areas covered: Given the importance of each step in the collagen biosynthesis, folding and signaling, medicinal chemists have explored small molecules, peptides, and monoclonal antibodies to modulate enzymes, receptors and interactions with the physiological ligands of collagen. These compounds were also explored toward diseases and pathological conditions. The authors discuss this providing their expert perspectives on the subject area.Expert opinion: Understanding collagen protein properties and its interactome is beneficial for therapeutic drug design. Nevertheless, compounds targeting collagen-based interactome suffered from the presence of different isoforms for each target and the lack of specific 3D crystal structures able to guide properly drug design.

Dual Acting Carbon Monoxide Releasing Molecules and Carbonic Anhydrase Inhibitors Differentially Modulate Inflammation in Human Tenocytes

Sustained oxidative stress and inflammation have been reported as the major factors responsible for the failure of tendon healing during rotator cuff tears (RCTs) and rotator cuff disease (RCD). Although, their therapeutic management remains still challenging. Carbonic anhydrases (CAs) are involved in many pathological conditions, and the overexpression of both CA9 and 12 in inflamed joints has been recently reported. Consequently, a selective CA9/12 inhibition could be a feasible strategy for improving tendon recovery after injury. In addition, since carbon monoxide (CO) has been proven to have an important role in modulating inflammation, CO releasing molecules (CORMs) can be also potentially suitable compounds. The present study aims at evaluating five newly synthesized dual-mode acting CA inhibitors (CAIs)-CORMs compounds, belonging to two chemical scaffolds, on tendon-derived human primary cells under H₂O₂ stimulation in comparison with Meloxicam. Our results show that compounds 2 and 7 are the most promising of the series in counteracting oxidative stress-induced cytotoxicity and display a better profile in terms of enhanced viability, decreased LDH release, and augmented tenocyte proliferation compared to Meloxicam. Moreover, compound 7, as a potent superoxide scavenger, exerts its action inhibiting NF-ĸB translocation and downregulating iNOS, whereas compound 2 is more effective in increasing collagen I deposition. Taken together, our data highlight a potential role of CA in RCTs and RCD and the prospective effectiveness of compounds acting as CAI-CORM during inflammation.