Effects of human amniotic fluid and membrane in the treatment of Achilles tendon ruptures in locally corticosteroid-induced Achilles tendinosis: an experimental study on rats

Challenges and opportunities of medicines for treating tendon inflammation and fibrosis: A comprehensive and mechanistic review

BACKGROUND

Tendinopathy refers to conditions characterized by collagen degeneration within tendon tissue, accompanied by the proliferation of capillaries and arteries, resulting in reduced mechanical function, pain, and swelling. While inflammation in tendinopathy can play a role in preventing infection, uncontrolled inflammation can hinder tissue regeneration and lead to fibrosis and impaired movement.

OBJECTIVES

The inability to regulate inflammation poses a significant limitation in tendinopathy treatment. Therefore, an ideal treatment strategy should involve modulation of the inflammatory process while promoting tissue regeneration.

METHODS

The current review article was prepared by searching PubMed, Scopus, Web of Science, and Google Scholar databases. Several treatment approaches based on biomaterials have been developed.

RESULTS

This review examines various treatment methods utilizing small molecules, biological compounds, herbal medicine-inspired approaches, immunotherapy, gene therapy, cell-based therapy, tissue engineering, nanotechnology, and phototherapy.

CONCLUSION

These treatments work through mechanisms of action involving signaling pathways such as transforming growth factor-beta (TGF-β), mitogen-activated protein kinases (MAPKs), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), all of which contribute to the repair of injured tendons.

Evaluation of Anti-Nociceptive, Anti-Inflammatory, and Anti-Fibrotic effects of noscapine against a rat model of Achilles tendinopathy

During tendinopathy, prolonged inflammation results in fibrosis and the adherence of tendons to the adjacent tissues, causing discomfort and movement disorders. As a natural compound, noscapine has several anti-inflammatory and anti-fibrotic properties. Therefore, we aimed to investigate the effects of noscapine against a rat model of tendinopathy. We created a surgical rat model of Achilles tendon damage to emulate tendinopathy. Briefly, an incision was made on the Achilles tendon, and it was then sutured using an absorbable surgical thread. Immediately, the injured area was topically treated with the vehicle, noscapine (0.2, 0.6, and 1.8 mg/kg), or dexamethasone (0.1 mg/kg) as a positive control. During the 19-day follow-up period, animals were assessed for weight, behavior, pain, and motor coordination testing. On day 20th, the rats were sacrificed, and the tendon tissue was isolated for macroscopic scoring, microscopic (H&E, Masson's trichrome, Ki67, p53) analyses, and cytokine secretion levels. The levels of macroscopic parameters, including thermal hyperalgesia, mechanical and cold allodynia, deterioration of motor coordination, tendon adhesion score, and microscopic indices, namely histological adhesion, vascular prominence and angiogenesis, and Ki67 and p53 levels, as well as fibrotic and inflammatory biomarkers (IL-6, TNF-α, TGF-β, VEGF) were significantly increased in the vehicle group compared to the sham group (P < 0.05-0.001 for all cases). In contrast, the administration of noscapine (0.2, 0.6, and 1.8 mg/kg) attenuated the pain, fibrosis, and inflammatory indices in a dose-dependent manner compared to the vehicle group (P < 0.05-0.001). Histological research indicated that noscapine 0.6 and 1.8 mg/kg had the most remarkable healing effects. Interestingly, two higher doses of noscapine had impacts similar to those of the positive control group in both clinical and paraclinical assessments. Taken together, our findings suggested that noscapine could be a promising medicine for treating tendinopathies.

Biomaterials for Tissue-Engineered Treatment of Tendinopathy in Animal Models: A Systematic Review

To conduct a systematic review of studies reporting the treatment of tendon injury using biomaterials in animal models. A systematic search was conducted to retrieve studies involving animal models of tendon repair using biomaterials, in PubMed (database construction to August 2022) and Ovid-Embase (1946 to August 2022). Data related to tendon repair with biomaterials were extracted by two researchers, respectively. Risk of bias was assessed following the Cochrane Handbook for Systematic Reviews of Interventions. A statistical analysis was performed based on the classification of tendon repair biomaterials included in our study. A total of 8413 articles were retrieved, with 78 studies included in our analysis. For tendon repair in animal models using biomaterials, the most commonly seen characteristics were as follows: naturally derived biomaterials, rabbits and rats as animal models, surgery as the injury model, and the Achilles tendon as the injury site. The histology and biomechanical recovery of tendon injury following repair are affected by different biomaterials. Studies of tendon repair in animal models indicate that biomaterials can significantly improve repair outcomes, including tendon structure and biomechanics. Among effective biomaterial strategies are the use of new composites and incorporation of cells or growth factors into the material, both of which provide obvious benefits for tendon healing. More high-quality preclinical studies are required to encourage the translation of biomaterials into clinical practice for tendon repair.

Protective and Therapeutic Effects of Bovine Amniotic Fluids Collected in Different Trimesters on the Epidural Fibrosis After Experimental Laminectomy in Rats

BACKGROUND

The aim of this study was to investigate the protective and therapeutic effects of bovine amniotic fluid (BAF) on the inhibition of epidural fibrosis (EF) after experimental laminectomy.

METHODS

Forty female Sprague Dawley rats were used. The amniotic fluids were collected from each trimester of a pregnant cow. The rats were divided into 5 groups. Whereas no laminectomy was applied to the control group, animals in the sham group underwent laminectomy. Laminectomy was performed in the animals in other groups and the operation area was closed by dripping 1 mL of BAF collected in 3 trimesters of pregnancy. Animals were killed 28 days after the operation.

RESULTS

Compared with control, VEGF gene expression levels were downregulated approximately 5-fold in BAF-2. Whereas IL-6 was upregulated approximately 8-fold in the sham, it was downregulated 5-fold and 3-fold in BAF-1 and BAF-2, respectively. There was downregulation in BAF-2 and BAF-3 in terms of CD105 gene expression levels. TGFβ1 was upregulated approximately 2-fold in the sham group and downregulated in BAF-1 and BAF-2. Although histopathologic alterations including EF grade and fibroblast cell density were found to increase in the sham group, all BAF treatment decreased those of alterations. The highest CD105 immunoreactivity was detected in the sham group. All BAF treatment markedly aggravated fibrosis via decreasing CD105 immunoreactivity. In terms of grading parameters, almost the closest grades to the control were determined in the BAF-2. BAF collected in the second trimester is most effective in healing of scar tissue and preventing fibrosis via decreasing microvessel and fibroblast densities.

CONCLUSIONS

The results indicate that BAF may be used as a potential protective agent to prevent EF.

Orthobiologic Use in Sports Injuries

Orthobiologics have gained much popularity in recent years but there has not been a large amount of clinical evidence to support their use. In the limited research that has been published, they have been shown to be effective and safe. They can assist in earlier return to activity with the avoidance of surgery. They can also augment current surgical practice to aid in healing and return to sport with few complications. With new medical innovation, there is unfortunately a higher cost for these products. The use of orthobiologics will only grow and so will the need for high-level clinical evidence.

Clinical and Histologic Evaluation of Partial Achilles Tendon Injury Repair with Amniotic Membrane in Rats

BACKGROUND

Adhesions after tendinopathy in individuals who perform physical work and those physically active in middle age are a challenging problem for orthopedic surgeons. We evaluated the effects of human-derivated amniotic membrane on tendon healing, adhesions, angiogenesis, and the inflammatory process.

METHODS

Thirty-five rats were divided evenly into five groups, and the left lower extremity was used in this study. No interventions were applied to the control group (group 5). In the other groups, Achilles tendons were partially cut to the midline. Then, primary repair (group 1), amniotic membrane treatment with no repair (group 2), primary repair and amniotic membrane treatment (group 3), or secondary healing with no repair (group 4) was performed.

RESULTS

Use of amniotic membrane in tendon healing resulted in decreased adhesion formation and positive effects on collagen sequencing and anti-inflammatory effects. In addition, for the vascular endothelial growth factor evaluation there was no difference among the amniotic membrane repair groups, but there was an increase in vascular endothelial growth factor positivity compared with the control group.

CONCLUSIONS

These data show that amniotic membrane treatment can alter biological behavior and induce surface-dependent angiogenesis and can have angiogenetic effects on ischemia and inflammation.

Biologic therapies for foot and ankle injuries

Introduction: The use of orthobiologics as supplemental treatment for foot and ankle pathologies have increased in the past decades. They have been used to improve the healing of bone and soft tissue injuries. There have been several studies that examined the use of biologics for knee and hip pathologies but the foot and ankle construct has unique features that must be considered.Areas covered: The biologics for foot and ankle injuries that are covered in this review are platelet-rich plasma (PRP), stem cells, growth factors, hyaluronic acid, bone grafts, bone substitutes, and scaffolds. These modalities are used in the treatment of pathologies related to tendon and soft tissue as well as cartilage.Expert opinion: The utilization of biological adjuncts for improved repair and regeneration of ankle injuries represents a promising future in our efforts to address difficult clinical problems. The application of concentrated bone marrow and PRP each represents the most widely studied and commonly used injection therapies with early clinical studies demonstrating promising results, research is also being done using other potential therapies such as stem cells and growth factors; further investigation and outcome data are still needed.

Nonoperative Applications of Placental Tissue Matrix in Orthopaedic Sports Injuries: A Review of Literature

OBJECTIVE

Recently, various amniotic tissue and placental-based tissue matrix (PTM) products have become increasingly available as a nonoperative treatment for tendinopathies and orthopaedic sports injuries. The aim of this review was to evaluate: (1) safety and efficacy of nonoperative use of PTM products, in acute and chronic tendon injuries and (2) the commercially available tissue options to better understand their differences.

DATA SOURCES

A comprehensive literature search was performed. Inclusion criteria were studies reporting on: (1) nonoperative uses of PTM therapy in sports injuries; and (2) clinical outcomes; in (3) human subjects. We excluded: (1) animal studies; (2) basic science studies; (3) non-English language literature; (4) review articles; and (5) duplicate studies. In addition, to determine the various product formulations, their tissue contents, and indications for use, we searched publicly available website content, marketing literature, and Food and Drug Administration (FDA) registration documents.

MAIN RESULTS

Current evidence investigated various PTM products for the treatment of various tendon injuries with demonstrated efficacy mainly in the short term with follow-up ranging between 6 weeks and 3 months. In addition, across all studies, no specific adverse events were reported. Substantial differences exist among the currently available products due to variations in their tissue source, formulations, processing methods, method of sterilization, preservation, and storage, indications for use, and FDA regulation.

CONCLUSIONS

Placental- and amniotic membrane-derived tissues seem to be safe for the nonoperative treatment of tendinopathies. However, several factors may affect the efficacy and safety profile of these products, and the orthopaedic surgeons should be aware of the differences.

Tendon regeneration induced by umbilical cord graft in a rabbit tendon defect model

Whether tendon regeneration can be induced using the umbilical cord as a whole-graft structure is unknown. In this study, we explored the potential for tendon regeneration induction using an umbilical cord graft in a rabbit model of patella tendon defects. In 52 of 54 New Zealand White rabbits, the central third of the patella tendons of both hind legs was removed to create tendon defects. The rabbits were randomly divided into four groups, nonfilling (empty defect), refilling (defect refilled with resected tendon portion), Wharton's jelly (WJ) outside (WJO; defect filled with umbilical cord graft, WJ side facing outward), and WJ inside (WJI; same as WJO with WJ side facing inward) groups. Four rabbits from WJO and WJI groups were sacrificed for human CD 105 evaluation 1 month after surgery. Further histological, biomechanical, and gene expression analyses were performed at 3 and 6 months after surgery. The untreated patella tendons in the remaining two rabbits were harvested as normal biomechanical controls. Histological evaluation showed that the formed tissue structure fibers in the tendon defect area were much denser and more mature in the WJI group than in all other groups. Biomechanical testing showed that the failure load of the final tissue structure was the highest in the WJI group. Real-time polymerase chain reaction indicated that the expression of most tendon-related genes was upregulated in the WJI group at 6 months after surgery. We concluded that umbilical cord grafting induces effective tendon regeneration, particularly when the WJ side faces inward.

Amnion Applications in the Foot and Ankle

Amnion and chorion products show great promise and have real potential to be mainstays of treatment for chronic, nonhealing wounds. Although amniotic products do carry a cost, the decrease in time to healing, with the assumed subsequent decrease in complication and infection rates, should also be taken into consideration. These products, with their unique biologic potential and availability in the clinical setting, may prove to be beneficial in a vast array of podiatric surgical applications.

The Placenta: Applications in Orthopaedic Sports Medicine

BACKGROUND

Placenta has a long history of use for treating burns and wounds. It is a rich source of collagen and other extracellular matrix proteins, tissue reparative growth factors, and stem cells, including mesenchymal stem cells (MSCs). Recent data show its therapeutic potential for orthopaedic sports medicine indications.

PURPOSE

To provide orthopaedic surgeons with an anatomic description of the placenta, to characterize its cellular composition, and to review the literature reporting the use of placenta-derived cells and placental tissue allografts for orthopaedic sports medicine indications in animal models and in humans.

STUDY DESIGN

Systematic review.

METHODS

Using a total of 63 keyword combinations, the PubMed and MEDLINE databases were searched for published articles describing the use of placental cells and/or tissue for orthopaedic sports medicine indications. Information was collected on placental tissue type, indications, animal model, study design, treatment regimen, safety, and efficacy outcomes. Results were categorized by indication and subcategorized by animal model.

RESULTS

Outcomes for 29 animal studies and 6 human studies reporting the use of placenta-derived therapeutics were generally positive; however, the placental tissue source, clinical indication, and administration route were highly variable across these studies. Fourteen animal studies described the use of placental tissue for tendon injuries, 13 studies for osteoarthritis or articular cartilage injuries, 3 for ligament injuries, and 1 for synovitis. Both placenta-derived culture-expanded cells (epithelial cells or MSCs) and placental tissue allografts were used in animal studies. In all human studies, commercial placental allografts were used. Five of 6 human studies examined the treatment of foot and ankle pathological conditions, and 1 studied the treatment of knee osteoarthritis.

CONCLUSION

A review of the small number of reported studies revealed a high degree of variability in placental cell types, placental tissue preparation, routes of administration, and treatment regimens, which prohibits making any definitive conclusions. Currently, the clinical use of placenta is limited to only commercial placental tissue allografts, as there are no placenta-derived biological drugs approved for the treatment of orthopaedic sports medicine conditions in the United States. However, this review shows that the application of placental cells or tissue allografts appears to be safe and has potential to improve outcomes for orthopaedic sports medicine indications.

Human Amniotic Membrane-Derived Products in Sports Medicine: Basic Science, Early Results, and Potential Clinical Applications

BACKGROUND

Amniotic membrane (AM)-derived products have been successfully used in ophthalmology, plastic surgery, and wound care, but little is known about their potential applications in orthopaedic sports medicine.

PURPOSE

To provide an updated review of the basic science and preclinical and clinical data supporting the use of AM-derived products and to review their current applications in sports medicine.

STUDY DESIGN

Systematic review.

METHODS

A systematic search of the literature was conducted using the Medline, EMBASE, and Cochrane databases. The search term amniotic membrane was used alone and in conjunction with stem cell, orthopaedic, tissue engineering, scaffold, and sports medicine.

RESULTS

The search identified 6870 articles, 80 of which, after screening of the titles and abstracts, were considered relevant to this study. Fifty-five articles described the anatomy, basic science, and nonorthopaedic applications of AM-derived products. Twenty-five articles described preclinical and clinical trials of AM-derived products for orthopaedic sports medicine. Because the level of evidence obtained from this search was not adequate for systematic review or meta-analysis, a current concepts review on the anatomy, physiology, and clinical uses of AM-derived products is presented.

CONCLUSION

Amniotic membranes have many promising applications in sports medicine. They are a source of pluripotent cells, highly organized collagen, antifibrotic and anti-inflammatory cytokines, immunomodulators, and matrix proteins. These properties may make it beneficial when applied as tissue engineering scaffolds, improving tissue organization in healing, and treatment of the arthritic joint. The current body of evidence in sports medicine is heavily biased toward in vitro and animal studies, with little to no human clinical data. Nonetheless, 14 companies or distributors offer commercial AM products. The preparation and formulation of these products alter their biological and mechanical properties, and a thorough understanding of these differences will help guide the use of AM-derived products in sports medicine research.

The Effect of Autologous Platelet Rich Plasma in the Treatment of Achilles Tendon Ruptures: An Experimental Study on Rabbits

BACKGROUND

Achilles tendon ruptures are characterized by a long recovery period, high re-rupture rate and late return to work. To overcome these difficulties and augment tendon repair, many agents have been used.

AIMS

To determine the effect of autologous platelet rich plasma (PRP) in the treatment of Achilles tendon ruptures in rabbits.

STUDY DESIGN

Animal experimentation.

METHODS

The study included 14 New Zealand albino rabbits that were divided randomly into 2 groups, A and B, each containing seven rabbits. On day zero, all 28 Achilles tendons were tenotomized and repaired. In group A, the tendons were injected with PRP post-surgery, whereas those in group B were left untreated. On day 28, the right tendons in both groups were examined histopathologically via both light and electron microscopy, and the left tendons were subjected to biomechanical testing.

RESULTS

The histological and biomechanical findings in both light and electron microscopy in group A were better than those in group B, but the difference was not significant. According to Tang's scale, the mean value in Group A was 3.57, while it was 3.0 in Group B. The mean value of Group A for the length of collagen bands was 48.09 nm while the mean value of Group B was 46.58 nm (p=0.406). In biomechanical tests, although stiffness values were higher in group A, the difference between groups was not significant. In addition, maximum load values did not differ between groups A and B.

CONCLUSION

PRP had no effect on the healing process 28 days post-Achilles tendon rupture.

Topical Review: Use of Fetal Tissue in Foot and Ankle Surgery

Fetal tissues are well known for their therapeutic potential. They contain numerous growth factors, cytokines, and matrix components that promote regeneration of tissues while downregulating inflammation and scar formation. As a result, use of these treatments has expanded over the previous 20 years throughout various surgical specialties, including orthopaedics. With improved methods of sterilization, processing, and storage, surgeons need to be informed about the potential benefits of fetal tissue in foot and ankle surgery. The aim of this review is to provide a brief historical background, basic anatomy and physiology, and a current review of the literature in regard to chronic wounds, diabetic foot ulcerations, plantar fasciitis, tendon repair, adhesion prevention, nerve repair, and bone healing.

LEVELS OF EVIDENCE

Level V: Expert Opinion.

The Effect of Phospholipids (Surfactant) on Adhesion and Biomechanical Properties of Tendon: A Rat Achilles Tendon Repair Model

Adhesion of the tendon is a major challenge for the orthopedic surgeon during tendon repair. Manipulation of biological environment is one of the concepts to prevent adhesion. Lots of biochemicals have been studied for this purpose. We aimed to determine the effect of phospholipids on adhesion and biomechanical properties of tendon in an animal tendon repair model. Seventy-two Wistar rats were divided into 4 groups. Achilles tendons of rats were cut and repaired. Phospholipids were applied at two different dosages. Tendon adhesion was determined histopathologically and biomechanical test was performed. At macroscopic evaluation of adhesion, there are statistically significant differences between multiple-dose phospholipid injection group and Control group and also hyaluronic acid group and Control group (p < 0.008). At microscopic evaluation of adhesion, there was no statistically significant difference (p > 0.008). Ultimate strength was highest at hyaluronic acid injection group and lowest at multiple-dose phospholipid injection group. Single-dose phospholipids (surfactant) application may have a beneficial effect on the tendon adhesion. Although multiple applications of phospholipids seem the most effective regime to reduce the tendon adhesion among groups, it deteriorated the biomechanical properties of tendon.