Effects of Tumor Necrosis Factor Inhibitor on Stress-Shielded Tendons

Sehnenpathologien im Bereich des Fußes – Inflammation versus Degeneration: wo liegen die Unterschiede?

Die Ursachen für Tendopathien bzw. Tenosynovialitiden sind mannigfaltig. Stoffwechsel und Genaktivität der Bindegewebszellen im Sehnengewebe reagieren sehr empfindlich auf mechanische Beanspruchung und aber auch entzündliche Reize im Hinblick auf die Integrität der extrazellulären Matrix. Hierin unterscheiden sich entzündliche und degenerative Sehnenerkrankungen nicht. Die verbesserten medikamentösen Möglichkeiten einer nachhaltigen Entzündungskontrolle erlaubt es dem Rheumaorthopäden auch häufiger sich an den fusschirurgischen Prinzipien eines Gelenkerhaltes orientieren zu können. Weiterhin erfordert jedoch die mit chronisch degenerativen Prozeßen nicht vergleichbare Entzündungsintensität einen ausreichenden Erfahrungsschatz im peri- und intraoperativen Umganges mit den RA, SpA und PsA Patienten.

Tetrandrine inhibits the occurrence and development of frozen shoulder by inhibiting inflammation, angiogenesis, and fibrosis

BACKGROUND

Frozen shoulders (FS) is a major clinical concern, where chronic synovial inflammation, abnormal angiogenesis, and fibrosis represent the critical pathologies in the glenohumeral capsule. However, no pharmacotherapy has been introduced to treat this pathology. Tetrandrine (TET) has been proposed as a treatment for many diseases due to its strong anti-inflammatory, anti-angiogenic, and anti-fibrotic effects.

PURPOSE

To study the anti-inflammatory, anti-angiogenic, and anti-fibrotic effects of TET on FS, and identify whether TET can prevent the development of FS in rats.

STUDY DESIGN

A controlled laboratory study.

METHODS

Forty-eight male Sprague-Dawley (SD) rats were randomly divided into control, TET, and FS groups. The TET group was intraperitoneally injected with TET every 2 days. TET and saline treatment were started on the day of FS surgery. After 8 weeks, the animals were sacrificed, and samples were collected for X-ray examination, glenohumeral range of motion (ROM) evaluation, histology and immunohistochemistry analysis, transmission electron microscopy (TEM) observation, and profibrogenic factors as well as proinflammatory cytokines measurements.

RESULTS

No significant difference in shoulder ROM was observed between the TET and control groups, but a significant difference was noted between these groups and the FS group (P < 0.01). Immunohistochemical staining showed no abnormal angiogenesis or fibrosis in the TET group or the control group. However, significant angiogenesis, collagen remodeling, and fibrosis were observed in the FS group, and the expression and proportion of type I and type III collagen in the FS group were significantly higher than those in the TET group or the control group (P < 0.01). TEM observation showed that TET protected the ultrastructure of collagen fibrous reticular arrangement of the articular capsule and prevented the formation of scar-like fibrotic structures, which are unique to FS. The significantly increased expression of Smad7 and the suppressed expression of Smad 2 in the TET group compared with that of the FS group indicated that TET also significantly inhibited the TGF-β1 intracellular signal pathway. The expression of profibrogenic factors and proinflammatory cytokines in the TET group and the control group was significantly lower than that in the TET group (P < 0.01).

CONCLUSION

The results demonstrated that TET protected the normal reticular structure of the capsule during the freezing period and prevented the development of FS by inhibiting inflammation, angiogenesis, and fibrosis in a rat FS model.

CLINICAL RELEVANCE

TET may be a safe and effective clinical medication for preventing and treating FS.

Reliable Reference Genes for Gene Expression Assessment in Tendon-Derived Cells under Inflammatory and Pro-Fibrotic/Healing Stimuli

Tendon cells (TCs) are important for homeostatic maintenance in the healthy tendon and to promote tissue healing after injury. Further, resident and rare populations of tendon stem/progenitor cells, located at various sites within the tendon, contribute to tendon recovery by differentiating into repairing TCs. Gene expression analysis, through quantitative reverse-transcription polymerase chain reaction (qRT-PCR), constitutes a useful tool to study cellular responses, including the transition from initial inflammation to healing processes. A critical step required for data normalization is the choice of reliable reference genes (RGs), a process highly underestimated in tendon biology. In this study, the suitability of five commonly used RGs (ACTB, B2M, GAPDH, HPRT1, and RPLP0) was evaluated using TCs samples cultured in both standard and progenitor-enriching conditions, as well as under either inflammatory (IFNγ + TNFα) or pro-fibrotic/healing (CTGF) stimulation. The stability of the candidate RGs was computationally determined using NormFinder, geNorm, BestKeeper, and DeltaCt applets. Overall, ACTB resulted as the most stable RG on the basis of the integration of each gene weight, whereas B2M and RPLP0 performed poorly. To further validate ACTB’s optimal performance, we evaluated the expression of ICAM1, coding for an immune-related cell surface glycoprotein, and COL1A1, encoding collagen type I that is the main component of the tendon extracellular matrix (ECM), both known to be modulated by inflammation. The expression of both genes was heavily affected by the RGs used. Consequently, when analyzing gene expression in tendon-derived cells subjected to various stimulatory protocols, the use of a suitable RG should be considered carefully. On the basis of our results, ACTB can be reliably used when analyzing different TC types exposed to pathological conditions.

Effects of etanercept, a tumor necrosis factor receptor fusion protein, on primary cell cultures prepared from intact human intervertebral disc tissue

The aim of the present study was to investigate the effects of etanercept (ETA), a tumor necrosis factor (TNF) inhibitor, on human cell cultures prepared from intact intervertebral disc tissue. ETA is used as a treatment for cases of rheumatoid arthritis, psoriatic arthritis, axial spondyloarthritis and ankylosing spondylitis accompanied by moderate or severe joint pain. ETA was applied to primary cell cultures [annulus fibrosus and nucleus pulposus (NP) from intact intervertebral disc tissue]. Cell cultures without ETA treatment served as the control group. Morphological and quantitative molecular analyses of the two groups were performed. The number of viable cells and cell proliferation decreased in the ETA-treated cultures as compared with those in the control group. Furthermore, in the treatment group, the chondroadherin gene, an NP-specific marker, was not expressed after 24 h. By contrast, the cartilage oligo matrix protein was expressed 24, 48 and 72 h post-ETA treatment, while its expression was significantly lower than that in the control group. In addition, the expression of interleukin-1β, as well as matrix metallopeptidase-7 and −19, was markedly decreased. Overall, the cell proliferation and gene expression in the ETA-treated cells were significantly different from those in the control group (P<0.05). These results suggest that the treatment duration and dosage of TNF inhibitors, which are used to suppress active inflammation, should be considered in the clinical setting. These biological agents may delay the healing of intervertebral disc tissue damage by slowing cell proliferation and altering gene expression via anabolic and catabolic pathways.

Tendon injury and repair - A perspective on the basic mechanisms of tendon disease and future clinical therapy

Tendon is an intricately organized connective tissue that efficiently transfers muscle force to the bony skeleton. Its structure, function, and physiology reflect the extreme, repetitive mechanical stresses that tendon tissues bear. These mechanical demands also lie beneath high clinical rates of tendon disorders, and present daunting challenges for clinical treatment of these ailments. This article aims to provide perspective on the most urgent frontiers of tendon research and therapeutic development. We start by broadly introducing essential elements of current understanding about tendon structure, function, physiology, damage, and repair. We then introduce and describe a novel paradigm explaining tendon disease progression from initial accumulation of damage in the tendon core to eventual vascular recruitment from the surrounding synovial tissues. We conclude with a perspective on the important role that biomaterials will play in translating research discoveries to the patient.

STATEMENT OF SIGNIFICANCE

Tendon and ligament problems represent the most frequent musculoskeletal complaints for which patients seek medical attention. Current therapeutic options for addressing tendon disorders are often ineffective, and the need for improved understanding of tendon physiology is urgent. This perspective article summarizes essential elements of our current knowledge on tendon structure, function, physiology, damage, and repair. It also describes a novel framework to understand tendon physiology and pathophysiology that may be useful in pushing the field forward.