scholarly journals Cell non-autonomous functions of S100a4 drive fibrotic tendon healing

2019 ◽  
Author(s):  
Jessica E. Ackerman ◽  
Valentina Studentsova ◽  
Katherine T. Best ◽  
Emma Knapp ◽  
Alayna E. Loiselle
Keyword(s):  
Mechanical Properties ◽  
Advanced Glycation Endproducts ◽  
Critical Role ◽  
Tendon Healing ◽  
Tendon Injury ◽  
Scar Formation ◽  
Acute Injury ◽  
Tissue Type ◽  
Fibrotic Scar

AbstractIdentification of pro-regenerative approaches to improve tendon healing is of critical importance given the diminished quality of life and physical function that accompanies the typical fibrotic response to tendon injury. S100a4 modulates fibrosis through tissue-type dependent mechanisms, and the role of S100a4 in fibrotic, scar-mediated tendon healing has not been established. In the present study we tested the hypothesis that inhibition of S100a4 improves tendon function following acute injury and surgical repair. We demonstrate cell non-autonomous functions of S100a4 as S100a4 haploinsufficiency promotes regenerative tendon healing, including decreased scar formation and improved mechanical properties. Moreover, inhibition of S100a4 via antagonism of its putative receptor, the Receptor for Advanced Glycation Endproducts (RAGE), also decreases scar formation. Mechanistically, knock-down of S100a4 decreases myofibroblast and macrophage content at the site of injury, with both cell populations being key drivers of fibrotic progression. In contrast, S100a4+ cell depletion displays time-dependent effects on scar formation, and consistent impairments in restoration of mechanical properties, indicating a critical role for these cells in re-establishing tendon strength after injury. Finally, we demonstrate, that S100a4-lineage cells become α-SMA+ myofibroblasts, via loss of S100a4 expression. Using a combination of genetic mouse models, small molecule inhibitors and in vitro studies we have defined S100a4 as a novel, promising therapeutic candidate to improve tendon function after acute injury.

scholarly journals Nonwoven-based gelatin/polycaprolactone membrane loaded with ERK inhibitor U0126 for treatment of tendon defects

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Yonghui Hou ◽  
Bingyu Zhou ◽  
Ming Ni ◽  
Min Wang ◽  
Lingli Ding ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Biomechanical Testing ◽  
Tendon Healing ◽  
Tendon Injury ◽  
Rna Seq ◽  
Injury Model ◽  
New Treatment ◽  
Underlying Mechanisms ◽  
And Control

Abstract Background Tendon is a major component of musculoskeletal system connecting the muscles to the bone. Tendon injuries are very common orthopedics problems leading to impeded motion. Up to now, there still lacks effective treatments for tendon diseases. Methods Tendon stem/progenitor cells (TSPCs) were isolated from the patellar tendons of SD rats. The expression levels of genes were evaluated by quantitative RT-PCR. Immunohistochemistry staining was performed to confirm the presence of tendon markers in tendon tissues. Bioinformatics analysis of data acquired by RNA-seq was used to find out the differentially expressed genes. Rat patellar tendon injury model was used to evaluate the effect of U0126 on tendon injury healing. Biomechanical testing was applied to evaluate the mechanical properties of newly formed tendon tissues. Results In this study, we have shown that ERK inhibitor U0126 rather PD98059 could effectively increase the expression of tendon-related genes and promote the tenogenesis of TSPCs in vitro. To explore the underlying mechanisms, RNA sequencing was performed to identify the molecular difference between U0126-treated and control TSPCs. The result showed that GDF6 was significantly increased by U0126, which is an important factor of the TGFβ superfamily regulating tendon development and tenogenesis. In addition, NBM (nonwoven-based gelatin/polycaprolactone membrane) which mimics the native microenvironment of the tendon tissue was used as an acellular scaffold to carry U0126. The results demonstrated that when NBM was used in combination with U0126, tendon healing was significantly promoted with better histological staining outcomes and mechanical properties. Conclusion Taken together, we have found U0126 promoted tenogenesis in TSPCs through activating GDF6, and NBM loaded with U0126 significantly promoted tendon defect healing, which provides a new treatment for tendon injury.

scholarly journals Short-Duration RAGE Antagonism Transiently Disrupts Tendon Homeostasis and does not Alter Diabetic Tendon Healing

2021 ◽  
Author(s):  
Anne EC Nichols ◽  
Samantha N Muscat ◽  
Alayna E Loiselle
Keyword(s):  
Advanced Glycation Endproducts ◽  
Healing Process ◽  
Tendon Repair ◽  
Tendon Healing ◽  
Type Ii Diabetes Mellitus ◽  
Tendon Injury ◽  
Acute Injury ◽  
Molecular Profile ◽  
Diet Induced Obesity ◽  
Increased Risk

Obesity and type II Diabetes Mellitus (T2DM) have substantial pathological effects on tendon homeostasis, including loss of collagen organization and increased risk of tendon rupture. Moreover, following rupture or acute injury, the healing process is impaired by T2DM. We have previously demonstrating that restoring normal metabolic function in a murine model of obesity/ T2DM is insufficient to blunt or reverse the progression of diabetic tendinopathy, indicating the need for identification of novel therapeutic approaches to both maintain tendon homeostasis, and to improve the healing process. RAGE, the Receptor for Advanced Glycation Endproducts has been implicated as a key driver of several diabetic pathologies. We have demonstrated that pharmacological antagonism of RAGE is sufficient to partially improve tendon healing in non-diabetic animals. Therefore, in the current study we tested the efficacy of blunted RAGE signaling, via treatment with a RAGE Antagonist Peptide (RAP), to improve tendon healing in the context of T2DM. While our study did not find a beneficial effect of short-term RAP treatment on the healing process of T2DM mice, we did identify several important challenges brought about by this model of diet-induced obesity and T2DM. Both high fat (HFD) and low fat diet (LFD) feeding shifted the temporal molecular profile of healing compared to standard laboratory chow fed mice. Moreover, RAP treatment resulted in a transient disruption in homeostasis in the contralateral control tendons of both HFD and LFD mice, and this was due to a potential interaction with the systemic response to tendon injury as this response was not observed in HFD and LFD fed mice that did not undergo tendon repair surgery. Collectively, these data highlight the complications associated with models of diet induced obesity, and the lean control diets that should be considered in future studies.

scholarly journals Effects of Redox Modulation on Cell Proliferation, Viability, and Migration in Cultured Rat and Human Tendon Progenitor Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yuk Wa Lee ◽  
Sai Chuen Fu ◽  
Man Yi Yeung ◽  
Chun Man Lawrence Lau ◽  
Kai Ming Chan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Proliferation ◽  
Vitamin C ◽  
Tendon Healing ◽  
In Vitro Study ◽  
Tendon Injury ◽  
Antioxidant Vitamin ◽  
Redox Modulation ◽  
And Migration

Tendon healing is slow and usually results in inferior fibrotic tissue formation. Recently, application of tendon derived stem cells (TDSCs) improved tendon healing in animal studies. In a chicken model, local injection of antioxidants reduced tendon adhesion after tendon injury. An in vitro study demonstrated that supplementation of H2O2reduced tenogenic marker expression in TDSCs. These findings suggested that the possibility of TDSCs is involved in tendon healing and the cellular activities of TDSCs might be affected by oxidative stress of the local environment. After tendon injury, oxidative stress is increased. Redox modulation might affect healing outcomes via affecting cellular activities in TDSCs. To study the effect of oxidative stress on TDSCs, the cellular activities of rat/human TDSCs were measured under different dosages of vitamin C or H2O2in this study. Lower dose of vitamin C increased cell proliferation, viability and migration; H2O2affected colony formation and suppressed cell migration, cell viability, apoptosis, and proliferation. Consistent with previous studies, oxidative stresses (H2O2) affect both recruitment and survival of TDSCs, while the antioxidant vitamin C may exert beneficial effects at low doses. In conclusion, redox modulation affected cellular activities of TDSCs and might be a potential strategy for tendon healing treatment.

Pifithrin-α, an inhibitor of p53 transactivation, alters the inflammatory process and delays tendon healing following acute injury

2007 ◽  
Vol 292 (1) ◽  
pp. R321-R327 ◽  
Author(s):  
David Marsolais ◽  
Claude H. Côté ◽  
Jérôme Frenette
Keyword(s):  
Extracellular Matrix ◽  
Inflammatory Process ◽  
Tendon Repair ◽  
Tendon Healing ◽  
Tendon Injury ◽  
Acute Injury ◽  
Inflammatory Phase ◽  
Load To Failure ◽  
Transcription Factor P53

Transcription factor p53, which was initially associated with cancer, has now emerged as an important regulator of inflammation and extracellular matrix homeostasis, two processes highly relevant to tendon repair. The goal of this study was to evaluate the effect of a p53 transactivation inhibitor, namely, pifithrin-α, on the pathophysiological sequence following collagenase-induced tendon injury. Administration of pifithrin-α during the inflammatory phase reduced the accumulation of neutrophils and macrophages by 30 and 40%, respectively, on day 3 postinjury. Pifithrin-α failed to reduce the percentage of apoptotic cells following collagenase injection but delayed functional recovery. In uninjured Achilles tendons, pifithrin-α increased metalloprotease activity 2.4-fold. Accordingly, pifithrin-α reduced the collagen content in intact tendons as well as in injured tendons 7 days posttrauma compared with placebo. The effect of pifithrin-α on load to failure and stiffness was also evaluated. The administration of pifithrin-α during the inflammatory phase did not significantly decrease the functional deficit 3 days posttrauma. More importantly, load to failure and stiffness were significantly decreased in the pifithrin-α group from day 7 to day 28 compared with placebo. Overall, our results suggest that administration of pifithrin-α alters the inflammatory process and delays tendon healing. The present findings also support the concept that p53 can regulate extracellular matrix homeostasis in vivo.

Tendon: Principles of Healing and Repair

2021 ◽  
Author(s):  
Christian Chartier ◽  
Hassan ElHawary ◽  
Aslan Baradaran ◽  
Joshua Vorstenbosch ◽  
Liqin Xu ◽  
...  
Keyword(s):  
Linear Growth ◽  
Tendon Rupture ◽  
Specific Treatment ◽  
Tendon Healing ◽  
Clinical Importance ◽  
Tendon Injury ◽  
Acute Injury ◽  
Hand Therapy ◽  
Optimal Care ◽  
Contractile Forces

AbstractTendon stores, releases, and dissipates energy to efficiently transmit contractile forces from muscle to bone. Tendon injury is exceedingly common, with the spectrum ranging from chronic tendinopathy to acute tendon rupture. Tendon generally develops according to three main steps: collagen fibrillogenesis, linear growth, and lateral growth. In the setting of injury, it also repairs and regenerates in three overlapping steps (inflammation, proliferation, and remodeling) with tendon-specific durations. Acute injury to the flexor and extensor tendons of the hand are of particular clinical importance to plastic surgeons, with tendon-specific treatment guided by the general principle of minimum protective immobilization followed by hand therapy to overcome potential adhesions. Thorough knowledge of the underlying biomechanical principles of tendon healing is required to provide optimal care to patients presenting with tendon injury.

Postnatal development of the fibrotic scar formation: An in vitro study

2011 ◽  
Vol 71 ◽  
pp. e338
Author(s):  
Yukari Komuta ◽  
Junko Kimura-Kuroda ◽  
Hiroko Yanagisawa ◽  
Kazunori Sango ◽  
Hitoshi Kawano
Keyword(s):  
Postnatal Development ◽  
In Vitro Study ◽  
Scar Formation ◽  
Vitro Study ◽  
Fibrotic Scar

scholarly journals Cell non-autonomous functions of S100a4 drive fibrotic tendon healing

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jessica E Ackerman ◽  
Anne EC Nichols ◽  
Valentina Studentsova ◽  
Katherine T Best ◽  
Emma Knapp ◽  
...  
Keyword(s):  
Surgical Repair ◽  
Tendon Healing ◽  
Acute Injury ◽  
Cell Populations ◽  
Putative Receptor ◽  
S100a4 Expression ◽  
A Cell ◽  
Key Drivers ◽  
Genetic Mouse Models

Identification of pro-regenerative approaches to improve tendon healing is critically important as the fibrotic healing response impairs physical function. In the present study we tested the hypothesis that S100a4 haploinsufficiency or inhibition of S100a4 signaling improves tendon function following acute injury and surgical repair in a murine model. We demonstrate that S100a4 drives fibrotic tendon healing primarily through a cell non-autonomous process, with S100a4 haploinsufficiency promoting regenerative tendon healing. Moreover, inhibition of S100a4 signaling via antagonism of its putative receptor, RAGE, also decreases scar formation. Mechanistically, S100a4 haploinsufficiency decreases myofibroblast and macrophage content at the site of injury, with both cell populations being key drivers of fibrotic progression. Moreover, S100a4-lineage cells become α-SMA+ myofibroblasts, via loss of S100a4 expression. Using a combination of genetic mouse models, small molecule inhibitors and in vitro studies we have defined S100a4 as a novel, promising therapeutic candidate to improve tendon function after acute injury.

scholarly journals Platelet-Rich Plasma Releasate Promotes Early Healing in Tendon After Acute Injury

2021 ◽  
Vol 9 (4) ◽  
pp. 232596712199037
Author(s):  
Tung-Yang Yu ◽  
Jong-Hwei S. Pang ◽  
Li-Ping Lin ◽  
Ju-Wen Cheng ◽  
Shih-Jung Liu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tensile Strength ◽  
Achilles Tendon ◽  
Platelet Rich Plasma ◽  
Testing Machine ◽  
Tendon Healing ◽  
Tendon Injury ◽  
The Other ◽  
Acute Injury ◽  
Early Healing

Background: Acute tendon injury can limit motion and thereby inhibit tendon healing. Positive results have been found after the use of platelet-rich plasma (PRP) to treat tendon injury; however, the early effects of PRP on tendon regeneration are not known. Purpose/Hypothesis: The purpose of this study was to evaluate the effects of PRP releasate (PRPr) on the early stages of tendon healing in a rat partial tenotomy model. It was hypothesized that PRPr can promote early healing of an Achilles tendon in rats. Study Design: Controlled laboratory study. Methods: PRP was prepared by a 2-step method of manual platelet concentration from 10 rats. PRPr was isolated from the clotted preparation after activation by thrombin and was applied to an Achilles tendon on 1 side of 30 rats on the second day after partial tenotomy, with normal saline used as the control on the other side. Achilles tendon samples were harvested 5 and 10 days after tenotomy. At each time point, 15 Achilles tendon samples were obtained, of which 5 samples were evaluated by Masson trichrome staining, apoptosis, and cell proliferation, while the other 10 samples were tested for tensile strength using a material testing machine. Results: Compared with saline-treated control tendons, the PRPr-treated tendons showed increased collagen synthesis near the cut edge and fewer apoptotic cells ( P = .01). An immunohistochemical analysis revealed more Ki-67–positive cells but fewer cluster of differentiation (CD) 68+ (ED1+) macrophages in PRPr tendons compared with saline-treated tendons ( P < .01). Tendons treated with PRPr also showed higher ultimate tensile strength than those treated with saline ( P = .03). Conclusion: PRPr treatment promotes tissue recovery in the early phase of tendon healing by stimulating tendon cell proliferation and collagen production while inhibiting cell apoptosis and CD68+ (ED1+) macrophage infiltration. Clinical Relevance: These findings suggest that with PRPr treatment, higher loads can be applied to the healing tendon at an earlier time, which can help the patient resume activity earlier.

scholarly journals In Vitro Effects of Bupivacaine on the Viability and Mechanics of Native and Engineered Cartilage Grafts

2021 ◽  
pp. 036354652199518
Author(s):  
Sarah Oyadomari ◽  
Wendy E. Brown ◽  
Heenam Kwon ◽  
Gaston Otarola ◽  
Jarrett M. Link ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Cartilage Explants ◽  
Toxic Effects ◽  
Tissue Type ◽  
Cartilage Tissue ◽  
Cartilage Grafts ◽  
Engineer Cartilage ◽  
In Vitro Effects

Background: Although the toxic effects of bupivacaine on chondrocyte monolayer culture have been well described, its cellular and mechanical effects on native and engineered articular cartilage remain unclear. For the repair of articular cartilage defects, fresh autologous and allogenic cartilage grafts are commonly used, and engineered cell-based therapies are emerging. The outcome of grafting therapies aimed at repairing damaged cartilage relies largely on maintaining proper viability and mechanical suitability of the donor tissues. Purpose: To investigate the in vitro effects of single bupivacaine exposure on the viability and mechanics of 2 cartilage graft types: native articular cartilage and engineered neocartilage. Study Design: Controlled laboratory study. Methods: Articular cartilage explants were harvested from the bovine stifle femoral condyles, and neocartilage constructs were engineered from bovine stifle chondrocytes using the self-assembling process, a scaffold-free approach to engineer cartilage tissue. Both explants and neocartilage were exposed to chondrogenic medium containing a clinically applicable bolus of 0.5%, 0.25%, or 0% (control) bupivacaine for 1 hour, followed by fresh medium wash and exchange. Cell viability and matrix content (collagen and glycosaminoglycan) were assessed at t = 24 hours after treatment, and compressive mechanical properties were assessed with creep indentation testing at t = 5 to 6 days after treatment. Results: Single bupivacaine exposure was chondrotoxic in both explants and neocartilage, with 0.5% bupivacaine causing a significant decrease in chondrocyte viability compared with the control condition (55.0% ± 13.4% vs 71.9% ± 13.5%; P < .001). Bupivacaine had no significant effect on matrix content for either tissue type. There was significant weakening of the mechanical properties in the neocartilage when treated with 0.5% bupivacaine compared with control, with decreased aggregate modulus (415.8 ± 155.1 vs 660.3 ± 145.8 kPa; P = .003), decreased shear modulus (143.2 ± 14.0 vs 266.5 ± 89.2 kPa; P = .002), and increased permeability (14.7 ± 8.1 vs 6.6 ± 1.7 × 10−15 m4/Ns; P = .009). Bupivacaine exposure did not have a significant effect on the mechanical properties of native cartilage explants. Conclusion: Single bupivacaine exposure resulted in significant chondrotoxicity in native explants and neocartilage and significant weakening of mechanical properties of neocartilage. The presence of abundant extracellular matrix does not appear to confer any additional resistance to the toxic effects of bupivacaine. Clinical Relevance: Clinicians should be judicious regarding the use of intra-articular bupivacaine in the setting of articular cartilage repair.

Fibrin-specificity of a Plasminogen Activator Affects the Efficiency of Fibrinolysis and Responsiveness to Ultrasound: Comparison of Nine Plasminogen Activators In Vitro

1999 ◽  
Vol 81 (04) ◽  
pp. 605-612 ◽  
Author(s):  
Dmitry V. Sakharov ◽  
Marrie Barrett-Bergshoeff ◽  
Rob T. Hekkenberg ◽  
Dingeman C. Rijken
Keyword(s):  
Thrombolytic Therapy ◽  
Plasminogen Activator ◽  
Tissue Type ◽  
Bolus Administration ◽  
High Frequency Ultrasound ◽  
Single Chain ◽  
Response Curves ◽  
Maximal Speed ◽  
Frequency Ultrasound

SummaryIn a number of cases, thrombolytic therapy fails to re-open occluded blood vessels, possibly due to the occurrence of thrombi resistant to lysis. We investigated in vitro how the lysis of hardly lysable model thrombi depends on the choice of the plasminogen activator (PA) and is accelerated by ultrasonic irradiation. Lysis of compacted crosslinked human plasma clots was measured after addition of nine different PAs to the surrounding plasma and the effect of 3 MHz ultrasound on the speed of lysis was assessed.Fibrin-specific PAs showed bell-shaped dose-response curves of varying width and height. PAs with improved fibrin-specificity (staphylokinase, the TNK variant of tissue-type PA [tPA], and the PA from the saliva of the Desmodus rotundus bat) induced rapid lysis in concentration ranges (80-, 260-, and 3,500-fold ranges, respectively) much wider than that for tPA (a 35-fold range). However, in terms of speed of lysis, these three PAs exceeded tPA only slightly. Reteplase and single-chain urokinase were comparable to tPA, whereas two-chain urokinase, anistreplase, and streptokinase were inferior to tPA. In the case of fibrin-specific PAs, ultrasonic treatment accelerated lysis about 1.5-fold. For streptokinase no acceleration was observed. The effect of ultrasound correlated with the presence of plasminogen in the outer plasma, suggesting that it was mediated by facilitating the transport of plasminogen to the surface of the clot.In conclusion, PAs with improved fibrin-specificity induce rapid lysis of plasminogen-poor compacted plasma clots in much wider concentration ranges than tPA. This offers a possibility of using single-or double-bolus administration regimens for such PAs. However, it is not likely that administration of these PAs will directly cause a dramatic increase in the rate of re-opening of the occluded arteries since they are only moderately superior to tPA in terms of maximal speed of lysis. Application of high-frequency ultrasound as an adjunct to thrombolytic therapy may increase the treatment efficiency, particularly in conjunction with fibrin-specific PAs.

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