Atelocollagen Injection Improves Tendon Integrity in Partial-Thickness Rotator Cuff Tears: A Prospective Comparative Study

Editorial Commentary: Biologic Augmentation of Rotator Cuff Repair: Platelet-Rich Plasma May Be of Significant Benefit, Whereas Atelocollagen Cannot Be Recommended

The field of orthobiologics continues to advance at a rapid pace and theoretically holds some promise to augment the biologic healing response in rotator cuff repair (RCR). However, the clinical evidence for use of substances such as platelet-rich plasma (PRP) for RCR remains inconclusive. Atelocollagen, as a synthetic collagen substitute, has been proposed as another alternative to provide more collagen substrate for healing, but outcomes data with this technique is lacking. In contrast, (biologic) PRP has been well studied, does not show adverse outcomes, and has been shown to improve healing of large to massive tears, as well as RCR outcomes. As biologic augmentation options continue to push the envelope on indications, due diligence is required to carefully examine options for safety and efficacy. Evolutions in RCR should also continue to motivate sports medicine surgeons and researchers to seek out further innovations to improve patient outcomes. That said, PRP outcome improvement for RCR is not definitive and requires further study. RCR can humble even the best of surgeons and demands that we continue to look for ways to improve outcomes.

Atelocollagen Injection During Arthroscopic Rotator Cuff Repair for Small- to Medium-Sized Subacute or Chronic Rotator Cuff Tears Enhances Radiographic Tendon Integrity: A Propensity Score-Matched Comparative Study

PURPOSE

To evaluate the clinical and structural outcomes of using injectable atelocollagen during arthroscopic rotator cuff repair (ARCR) for small- to medium-sized rotator cuff tears.

METHODS

This retrospective study reviewed patients with small- to medium-sized full-thickness tears who underwent ARCR from 2016 to 2022 with a minimum 1-year follow-up. Propensity score (PS) matching was used to reduce bias. Tendon integrity was evaluated using magnetic resonance imaging (MRI) at postoperative 6 months. Clinical and structural outcomes were compared between the 2 groups.

RESULTS

After PS matching, this study included 181 pairs of patients comparing ARCR with atelocollagen injection and without atelocollagen injection. Range of motion, muscle strength, and functional outcomes were significantly improved in both the atelocollagen group and the control group. Forward elevation and external rotation were significantly worse in the atelocollagen group compared with the control group at 2, 6, and 12 months postoperatively and at the final follow-up. In total, 125 patients (69.1%) in the atelocollagen group and 130 patients (71.8%) in the control group exceeded the minimal clinically important difference in the American Shoulder and Elbow Surgeons score without a significant difference between the 2 groups (P = .509). The mean value of Sugaya grade on postoperative MRI evaluation was 2.03 ± 0.81 for the atelocollagen group and 2.24 ± 0.97 for the control group, with a significant difference between the 2 groups (P = .027). Tendon healing failure was observed in 12 patients (6.6%) in the atelocollagen group and 19 patients (10.5%) in the control group, with no statistical difference between the 2 groups (P = .189).

CONCLUSIONS

Atelocollagen injection during ARCR for small- to medium-sized subacute or chronic rotator cuff tears did not show a benefit in clinical outcomes. However, postoperative MRI showed significantly lower Sugaya grade compared with the control group, with no significant difference in retear rate.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Fabrication of atelocollagen-coated bioabsorbable suture and the evaluation of its regenerative efficacy in Achilles tendon healing using a rat experimental model

Recently, the incidence of Achilles tendon ruptures (ATRs) has become more common, and repair surgery using a bioabsorbable suture is generally preferred, particularly in the case of healthy patients. Sutures composed of poly(lactic-co-glycolic acid) (PLGA) are commonly used in ATR surgeries. Nevertheless, owing to the inherent limitations of PLGA, novel bioabsorbable sutures that can accelerate Achilles tendon healing are sought. Recently, several studies have demonstrated the beneficial effects of atelocollagen on tendon healing. In this study, poly(3,4-dihydroxy-L-phenylalanine) (pDOPA), a hydrophilic biomimetic material, was used to modify the hydrophobic surface of a PLGA suture (Vicryl, VC) for the stable coating of atelocollagen on its surface. The main objective was to fabricate an atelocollagen-coated VC suture and evaluate its performance in the healing of Achilles tendon using a rat model of open repair for ATR. Structural analyses of the surface-modified suture indicated that the collagen was successfully coated on the VC/pDOPA suture. Postoperative in vivo biomechanical analysis, histological evaluation, ultrastructural/morphological analyses, and western blotting confirmed that the tendons in the VC/pDOPA/Col group exhibit superior healing than those in the VC and VC/pDOPA groups after 1 and 6 weeks following the surgery. The this study suggests that atelocollagen-coated PLGA/pDOPA sutures are preferable for future medical applications, especially in the repair of ATR.

Effect of Porcine-Derived Absorbable Patch-Type Atelocollagen for Arthroscopic Rotator Cuff Repair: A Prospective Randomized Controlled Trial

BACKGROUND

Even though arthroscopic rotator cuff repair is recognized as a standard treatment option, the risk of postoperative retear is a major concern.

PURPOSE

To evaluate the effect of porcine-derived absorbable patch-type atelocollagen during arthroscopic rotator cuff repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 64 patients with rotator cuff tears diagnosed on magnetic resonance imaging (MRI) were enrolled prospectively from November 2020 to December 2021. Both groups had repairs using the suture bridge technique. For the atelocollagen group, before securing the lateral anchors, we inserted porcine-derived absorbable patch-type atelocollagen between the footprint and the tendon. On postoperative day 2, the patients underwent MRI to confirm containment of the patch-type atelocollagen. At 6 months and 1 year postoperatively, the signal intensity of the repaired tendon was assessed using MRI. Patients were evaluated using the Constant score as the primary outcome, along with the visual analog scale for pain; range of motion; American Shoulder and Elbow Surgeons score; University of California, Los Angeles, score; and Korean Shoulder Score preoperatively and at 2, 3, 6, and 12 months postoperatively.

RESULTS

No significant changes in the Constant score as primary outcome, pain or other functional scores, and range of motion were observed between the groups at 1 year postoperatively. The patch-type atelocollagen was confirmed to be contained by the time-zero MRI scan taken 2 days postoperatively. Among the 55 patients included in final analysis, 12 retear cases were recorded (21.8% retear rate). A significantly lower retear rate was found in the atelocollagen group, as 3 cases were observed in this group (10.3%) and 9 cases were observed in the conventional repair group (34.6%) (P = .048).

CONCLUSION

The Constant score was not different between the groups. The retear rate after rotator cuff repair was significantly lower in the group that received porcine-derived absorbable patch-type atelocollagen compared with in the conventional group.

REGISTRATION

KCT0005184 (Clinical Research Information Service [CRIS]; https://cris.nih.go.kr).

Effects of Paraspinal Intramuscular Injection of Atelocollagen in Patients with Chronic Low Back Pain: A Retrospective Observational Study

Background/Objectives: Atelocollagen is used for soft tissue repair and reconstruction by replacing defective or damaged muscles, membranes, ligaments, and tendons. This study aimed to evaluate the clinical efficacy and safety of additional paraspinal intramuscular injection of atelocollagen on lumbar epidural steroid injection for reducing pain and improving functional capacity of patients with chronic low back pain (CLBP). Methods: We retrospectively enrolled 608 consecutive patients with CLBP who received lumbar epidural steroid injection with or without additional paraspinal intramuscular injection of atelocollagen. The Numerical Rating Scale and the Oswestry Disability Index were used to assess pain and functional capacity, respectively, before the procedure, and three months after the injection. Also, we analyzed the relationship between the additional paraspinal intramuscular injection of atelocollagen and the success rate. Results: Both Numerical Rating Scale and the Oswestry Disability Index scores were significantly reduced in both groups at three months after injection. However, there was a significant difference between the two groups. Furthermore, the success rate was significantly higher in the additional paraspinal intramuscular injection of atelocollagen group. Conclusions: This study's results showed that additional paraspinal intramuscular injection of atelocollagen on lumbar epidural steroid injection reduced pain and improved functional capacity for patients with CLBP. Therefore, the paraspinal intramuscular injection of atelocollagen may be a promising option for the treatment of patients with CLBP.

Effects of ultrasound-guided platelet-rich plasma combined with sodium hyaluronate on shoulder function recovery, pain degree and mental health of patients with rotator cuff injury

Rotator cuff injury is a common condition that affects the shoulder and is characterized by damage to the tendons and muscles in the shoulder area. This type of injury can lead to decreased shoulder function, pain, and decreased quality of life for those affected. As such, finding effective treatments for rotator cuff injury is important for improving patient outcomes and reducing the impact of this condition on patients and society. The purpose of this study was to evaluate the effectiveness of SH (Sodium Hyaluronate) and PRP (Platelet-Rich Plasma) in treating rotator cuff injuries in the shoulder. Patients who were diagnosed with Rotator Cuff Injury (RCI) and received treatment at the hospital were selected as the study subjects and divided into four groups. Various treatments were given to patients in each group. Two-way ANOVA and Mann-Whitney tests were used to analyze the results. The study found that patients who received ultrasound-guided platelet-rich plasma combined with sodium hyaluronate had significantly higher shoulder function recovery rates and better quality of life compared to the other groups. They also reported significantly lower pain scores compared to the other groups. The results suggest that ultrasound-guided platelet-rich plasma combined with sodium hyaluronate can effectively improve the shoulder function of patients with rotator cuff injury, reducing pain and improving their overall well-being. This has implications for improving patient outcomes and reducing the impact of rotator cuff injury on patients and society by providing a promising treatment option for this common condition.

Partial-thickness rotator cuff tears: a review of current literature on evaluation and management

Rotator cuff disease is a common cause of shoulder pain for which partial-thickness rotator cuff tears occupy a significant proportion. Such tears are often difficult to diagnose and manage in the general clinic setting. A review of the available literature from well-known databases was performed in this study to provide a concise overview of partial-thickness rotator cuff tears to aid physicians in their understanding and management.

[On the use of type I tropocollagen for local injection therapy of spine, upper and lower extremity disorders]

A meeting of Interdisciplinary Expert Panel with leading specialists in the field of orthopedics/traumatology, surgery, rheumatology, and neurology was held in Moscow on February 10, 2023. The purpose of the meeting was to discuss the current status of local injection therapy (LIT) in Russia and the rationale behind the use of collagen-based products for various musculoskeletal disorders. The experts considered the following issues: (1) General contraindications to the use of medical products based on tropocollagen as well as an algorithm for actions in case of adverse events; (2) Guidelines regarding LIT in general and LIT using tropocollagen in particular, including in combination with other LIT products; (3) Particular indications and approaches to the treatment of patients with abnormal changes in appendicular joints and spine with damage to both intra-articular structures and periarticular soft tissue.

Atelocollagen Injections Improve Outcomes in the Nonsurgical Treatment of Grade III Medial Collateral Ligament Injuries

Background

The purpose of this study was to evaluate the clinical outcomes of atelocollagen injections in isolated grade III medial collateral ligament (MCL) injuries of the knee joint.

Methods

A total of 50 participants were included in this retrospective study. Twenty-six patients underwent conservative treatment with a single atelocollagen injection, while the remaining patients underwent only typical conservative treatment. All participants underwent magnetic resonance imaging to identify and grade MCL injury. Valgus stress radiography was performed on both knees at 6 and 12 months after the injury. The visual analog scale (VAS) score was collected at the first visit and at 2 weeks, 6 weeks, 6 months, and 12 months after injury. The International Knee Documentation Committee (IKDC) formula activity level and Lysholm score were evaluated for patient-reported outcomes at the first visit and at 6 and 12 months after injury. The participant's return to the pre-injury activity level ratio was measured by comparing the IKDC formula activity level at 12 months after the injury with that before the injury.

Results

The VAS and Lysholm scores improved over time in both groups. The VAS and Lysholm scores were significantly better in the collagen injection group than in the control group. Regarding the activity level, the collagen injection group showed significantly better results at the 6-month follow-up, but there was no significant difference at the 12-month follow-up. The medial gap in the injured knee and the side-to-side difference (SSD) in both groups gradually decreased over time. The SSD in the collagen injection group was significantly smaller than that in the control group.

Conclusions

Atelocollagen injections resulted in better clinical and radiologic outcomes along with a higher rate of return to the pre-injury activity level, thereby exhibiting a positive effect in the nonsurgical treatment of grade III MCL injuries.

Effects of Arthroscopic Atelocollagen Insertion in High-Grade Partial Articular Supraspinatus Tendon Avulsion Lesions: A Retrospective Cohort Study With Propensity Score Matching

Background

This study sought to evaluate the effect of atelocollagen insertion into the bone-tendon interface of the repaired tendon after arthroscopic rotator cuff repair for high-grade partial articular supraspinatus tendon avulsion (PASTA) lesions.

Purpose

To compare clinical and radiological outcomes of atelocollagen-inserted rotator cuff repair and atelocollagen-noninserted rotator cuff repair in the high-grade PASTA lesions.

Study Design

Cohort study; Level of evidence, 3.

Methods

The data from 301 consecutive patients who underwent arthroscopic rotator cuff repair of PASTA lesions between January 2017 and June 2020 were retrospectively reviewed. Patients with minimum 2-year follow-up data were included and divided into 2 groups: those treated with transtendon suture-bridge repair without additional augmentation (group 1) and those with atelocollagen-inserted transtendon suture-bridge repair (group 2). Patients in group 2 were matched 1:1 to patients in group 1 using propensity score matching (n = 68 per group); and pain visual analog scale, American Shoulder and Elbow Surgeons, University of California, Los Angeles, Korean Shoulder Scoring System, Simple Shoulder Test, and range of motion scores were compared between these groups. Also, repaired tendon integrity and thickness were compared immediately, 6 months, and 1 year after surgery on magnetic resonance imaging (MRI) using the vertical distance from the midpoint footprint of the greater tuberosity.

Results

In most comparisons, there were no significant differences in outcome measures and range of motion between groups. However, less residual discomfort at the final follow-up was also documented in group 2 (P = .043). Also, the difference in forward flexion was 3.7° at 1 year and 5.4° at final follow-up, and the difference in abduction was 2.2° at final follow-up, which were all significantly greater in the experimental group. Group 2 showed significant greater tendon thickness of the repaired tendon immediately, 6 months, and 1 year after surgery on MRI (P≤ .001).

Conclusion

Addition of atelocollagen did not improve outcome scores. However, there was slightly greater flexion and abduction at final follow-up. Also, there was less residual discomfort at final follow-up.

An Atelocollagen Injection Enhances the Healing of Nonoperatively Treated Achilles Tendon Tears: An Experimental Study in Rats

Background

There is growing interest in nonoperative treatment for the management of Achilles tendon ruptures (ATRs). However, nonoperative treatment is limited by the risk of tendon reruptures and low satisfaction rates. Recently, atelocollagen injections have been reported to have beneficial effects on tendon healing.

Purpose

To evaluate the beneficial effects of injected atelocollagen on Achilles tendon healing and investigate the mechanism of atelocollagen on tendon healing.

Study Design

Controlled laboratory study.

Methods

Percutaneous tenotomy of the right Achilles tendon in 66 rats was performed. The animals were equally divided into the noninjection group (NG) and the collagen injection group (CG). At 1, 3, and 6 weeks, the Achilles functional index, cross-sectional area, load to failure, stiffness, stress, and the modified Bonar score were assessed. Transmission electron microscopy, western blotting, and immunohistochemistry were also performed.

Results

The Achilles functional index (-6.8 vs -43.0, respectively; P = .040), load to failure (42.1 vs 27.0 N, respectively; P = .049), and stiffness (18.8 vs 10.3 N/mm, respectively; P = .049) were higher in the CG than those in the NG at 3 weeks. There were no significant differences in histological scores between the 2 groups. Transmission electron microscopy analysis showed that the mean diameter of collagen fibrils in the CG was greater than that in the NG at 3 weeks (117.2 vs 72.6 nm, respectively; P < .001) and 6 weeks (202.1 vs 144.0 nm, respectively; P < .001). Western blot analysis showed that the expression of collagen type I in the CG was higher than that in the NG at 1 week (P = .005) and 6 weeks (P = .001).

Conclusion

An atelocollagen injection had beneficial effects on the healing of nonoperatively treated Achilles tendon injuries. The Achilles tendon of CG rats exhibited better functional, biomechanical, and morphological outcomes compared with NG rats. The molecular data indicated that the mechanism of atelocollagen injections may be associated with an increased amount of collagen type I.

Clinical Relevance

An atelocollagen injection might be a good adjuvant option for the nonoperative treatment of ATRs.

Conservative Management of Partial Thickness Rotator Cuff Tears: A Systematic Review

BACKGROUND

Conservative management has emerged as an attractive option for partial thickness rotator cuff tears (PT-RCTs). A single algorithmic treatment strategy for patients with symptomatic PT-RCT has not yet been developed. This systematic review aims to ascertain whether a conservative approach to PT-RCTs yields positive results in terms of clinical outcomes and functional recovery.

METHODS

This is a systematic review of the literature on patients with PT-RCTs receiving conservative treatment with physiotherapy, platelet-rich plasma (PRP) injections, collagen injections, hyaluronic acid (HA) injections, or corticosteroids injections coupled with polydeoxyribonucleotide (PDRN). Outcomes such as the Visual Analog Scale (VAS) for pain, American Shoulder and Elbow Surgeons and Constant-Murley Score evaluations, as well as the Shoulder Pain and Disability Index and Euro Quality of Life-5D questionnaires were reported following a conservative approach.

RESULTS

Eleven studies were included. Six articles explored the outcomes of patients with PT-RCT treated with PRP injections. Significant improvements in VAS for pain were observed. Two studies examined collagen injections and reported variations in VAS for pain and Constant-Murley Score. Sodium hyaluronate and HA injections were studied in two other articles, showing notable improvements in American Shoulder and Elbow Surgeons scores. Corticosteroid and PDRN injections also displayed favorable outcomes. In addition, physical therapy protocols demonstrated improvements in VAS for pain and strength, particularly with eccentric rehabilitation.

CONCLUSIONS

Conservative management of PT-RCTs, involving physical therapy, PRP injections, collagen injections, corticosteroid injections, HA injections, and PDRN in jections, demonstrates favorable clinical outcomes. In addition, favorable results are observed in terms of decreased tear width and improved strength recovery, at least during a short-term follow-up. Unfortunately, long-term insight into the structural integrity of conservatively treated rotator cuff tendons following a partial injury has not been thoroughly evaluated yet.

STUDY DESIGN LEVELS OF EVIDENCE

Level IV-systematic review.

Outcome of intraoperative injection of collagen in arthroscopic repair of full-thickness rotator cuff tear: a retrospective cohort study

BACKGROUND

Rotator cuff (RC) pathologies are considered the most common cause of shoulder disability and pain. Arthroscopic repair of RC tears has proven to be an effective operation. Nonhealing and retear remain significant clinical problems and a challenge to surgeons. In addition, the essential biological augment to enhance RC tendon-bone healing is still under research. The purpose of the study was to assess the safety and efficacy of injection of atelocollagen and acellular dermal matrix (ADM) allograft in arthroscopic repair of full-thickness RC tears.

METHODS

From January 2018 to March 2020, a total of 129 patients with full-thickness RC tear were treated by arthroscopic repair only (group 1, n = 36, with a mean age = 63.2 years), arthroscopic repair together with atelocollagen 1-mL injection (group 2, n = 44, with a mean age = 63 years), or RC tears together with ADM allograft 1-mL injection (group 3, n = 49, with a mean age = 64.6 years). They were prospectively studied. This study included patients with a repairable full-thickness tear of the supraspinatus tendon size <5 cm. We excluded patients with isolated tears of the subscapularis tendon, those with a previous shoulder surgery, and those who had any type of injection for less than 6 weeks. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score, Constant Shoulder score, visual analog scale pain score, and range of motion were evaluated preoperatively, at 3, 6, and 12 months of the postoperative period and the final follow-up. In addition, magnetic resonance imaging was performed at 2 months and 12 months postoperatively.

RESULTS

The mean follow-up period was 20 months. All groups showed improvement in functional and pain score at the final follow-up; however, there is no superior outcome among the 3 groups (P > .05). After 2 months, the nonhealing rate was 11% (4 of 36) for group 1, 4% (2 of 44) for group 2, and 2% (1 of 49) for group 3 (P > .05). The retear rates after 12 months was 19.4% (7 of 36) for group 1, 13.6% (6 of 44) for group 2, and 20.4% (10 of 49) for group 3 (P > .05). Adverse events were not detected in any groups.

CONCLUSION

Our study did not show superior clinical or radiologic outcomes of atelocollagen and ADM allograft injections in arthroscopic RC repair over 12 months of follow-up in comparison to the control group. However, adverse events related to atelocollagen and ADM allograft injection were not observed.

An Update on the Clinical Efficacy and Safety of Collagen Injectables for Aesthetic and Regenerative Medicine Applications

Soft tissues diseases significantly affect patients quality of life and usually require targeted, costly and sometimes constant interventions. With the average lifetime increase, a proportional increase of age-related soft tissues diseases has been witnessed. Due to this, the last two decades have seen a tremendous demand for minimally invasive one-step resolutive procedures. Intensive scientific and industrial research has led to the recognition of injectable formulations as a new advantageous approach in the management of complex diseases that are challenging to treat with conventional strategies. Among them, collagen-based products are revealed to be one of the most promising among bioactive biomaterials-based formulations. Collagen is the most abundant structural protein of vertebrate connective tissues and, because of its structural and non-structural role, is one of the most widely used multifunctional biomaterials in the health-related sectors, including medical care and cosmetics. Indeed, collagen-based formulations are historically considered as the "gold standard" and from 1981 have been paving the way for the development of a new generation of fillers. A huge number of collagen-based injectable products have been approved worldwide for clinical use and have routinely been introduced in many clinical settings for both aesthetic and regenerative surgery. In this context, this review article aims to be an update on the clinical outcomes of approved collagen-based injectables for both aesthetic and regenerative medicine of the last 20 years with an in-depth focus on their safety and effectiveness for the treatment of diseases of the integumental, gastrointestinal, musculoskeletal, and urogenital apparatus.

Exploring the Effects of 630 nm Wavelength of Light-Emitting Diode Irradiation on the Proliferation and Migration Ability of Human Biceps Tendon Fibroblast Cells

Background

Light-emitting diode (LED)-based photobiomodulation is used as an inducer of cell regeneration. Although numerous in vitro and in vivo orthopedic studies have been conducted, the ideal LED wavelength range for tendon healing has not yet been determined. This study, thus, focused on the effects of LED of a 630 nm wavelength on the cell viability, proliferation, and migration of human biceps tendon fibroblast cells.

Methods

Human tendon fibroblast cell culture was performed using the biceps tendon of patients who had undergone biceps tenodesis. Human biceps tendon fibroblasts from two patients (male, aged 42 and 69 years) were isolated and cultured. The cell type was confirmed by a morphological analysis and using tendon and fibroblast specific markers. They were then split into three groups, with each receiving a different irradiation treatment: no LED treatment (control), 630 nm LED, and 630 nm + 880 nm LED for 20 minutes each. After the LED treatment, cell viability, proliferation, and migration assays were performed, and the results were compared between the groups.

Results

Twenty-four hours after LED treatment, cell viability and proliferation were significantly increased in the 630 nm LED and 630 nm + 880 nm LED treatment groups compared to that in the control group (p < 0.05). Under the same conditions, compared with the control group, the 630 nm LED alone treatment group showed a 3.06 ± 0.21 times higher cell migration rate (p < 0.05), and the 630 nm + 880 nm LED combination treatment group showed a 2.88 ± 0.20 times higher cell migration rate (p < 0.05) in three-dimensional migration assay.

Conclusions

In human tendon fibroblast cells, 20 minutes of LED treatment at 630 nm and 630 nm + 880 nm exhibited significant effects on cell proliferation and migration. Our findings suggest the potential of LED therapy as an adjuvant treatment for tendon healing, and hence, further research is warranted to standardize the various parameters to further develop and establish this as a reliable treatment regimen.

Comparative analysis of Achilles tendon healing outcomes after open tenotomy versus percutaneous tenotomy: An experimental study in rats

There is growing interest in conservative treatment of Achilles tendon rupture. However, the majority of experimental studies of Achilles tendon have been performed by open tenotomy. More appropriate model of conservative treatment of Achilles tendon rupture is required. We performed an experimental study to evaluate whether outcomes differ between open tenotomy and percutaneous tenotomy of the Achilles tendon in rats. The Achilles tendons of 48 rats were transected. The animals were divided into two groups according to surgical technique: open tenotomy or microscopy-assisted percutaneous tenotomy. After 1, 2, and 4 weeks, functional, biomechanical, and histological analyses were performed. Western blot was performed for quantitative molecular analysis at 1 week. The Achilles functional index was superior in the percutaneous tenotomy group, compared with the open tenotomy group, at 1 week. The cross-sectional area was significantly larger in the percutaneous tenotomy group than in the open tenotomy group at 4 weeks. Relative to the native tendons, load to failure and stiffness yielded comparable results at 2 weeks in the percutaneous tenotomy group and at 4 weeks in the open tenotomy group. The histological score was significantly better in the percutaneous tenotomy group than in the open tenotomy group at 1 week. At 1 week, interleukin-1β expression in the open tenotomy group was higher than in the percutaneous tenotomy group. In summary, Achilles tendon healing was substantially affected by the tenotomy method. We presume that our percutaneous tenotomy method might constitute a useful experimental animal model for conservative treatment of Achilles tendon rupture.

Fish Gelatin: Current Nutritional, Medicinal, Tissue Repair Applications and Carrier of Drug Delivery

Gelatin is obtained via partial denaturation of collagen and is extensively used in various industries. The majority of gelatin utilized globally is derived from a mammalian source. Several health and religious concerns associated with porcine/bovine gelatin were reported. Therefore, gelatin from a marine source is widely being investigated for its efficiency and utilization in a variety of applications as a potential substitute for porcine/bovine gelatin. Although fish gelatin is less durable and possesses lower melting and gelling temperatures compared to mammal-derived gelatin, various modifications are being reported to promote its rheological and functional properties to be efficiently employed. The present review describes in detail the current innovative applications of fish gelatin involving the food industry, drug delivery and possible therapeutic applications. Gelatin bioactive molecules may be utilized as carriers for drug delivery. Due to its versatility, gelatin can be used in different carrier systems, such as microparticles, nanoparticles, fibers and hydrogels. The present review also provides a perspective on the other potential pharmaceutical applications of fish gelatin, such as tissue regeneration, antioxidant supplementation, antihypertensive and anticancer treatments.

Effect of co-administration of atelocollagen and hyaluronic acid on rotator cuff healing

Background

This study aimed to evaluate the co-administration effect of atelocollagen combined with hyaluronic acid (HA) injections for treatment of full-thickness rotator cuff tear (RCT).

Methods

Eighty patients who underwent arthroscopic rotator cuff repair for full-thickness RCT from March 2018 to November 2019 were enrolled. The patients were randomly allocated to the following groups: combined atelocollagen and HA injection (group I, n=28), only HA injection (group II, n=26), and no injection (group III, n=26). Clinical outcomes were assessed at 3, 6, and 12 months after surgery using the American Shoulder and Elbow Surgeons score, visual analog scale pain score , functional scores (pain visual analog scale, function visual analog score), and range of motion. Magnetic resonance imaging was performed 12 months after surgery to evaluate rotator cuff integrity.

Results

Preoperative demographic data and postoperative clinical outcomes did not differ significantly among the three groups (p>0.05). However, in group I, the number of steroid injections after surgery was significantly lower than that in the other groups (p=0.011). The retear rate on follow-up magnetic resonance imaging was significantly higher in group II (9.5%, n=2) and group III (13.6%, n=3) than in group I (0%) (p=0.021).

Conclusions

Co-administration of atelocollagen and HA improves healing of the rotator cuff and increases the integrity of the rotator cuff repair site. This study provides encouraging evidence for use of combined atelocollagen-HA injections to treat patients with full-thickness RCT.

Employing Extracellular Matrix-Based Tissue Engineering Strategies for Age-Dependent Tissue Degenerations

Tissues and organs are not composed of solely cellular components; instead, they converge with an extracellular matrix (ECM). The composition and function of the ECM differ depending on tissue types. The ECM provides a microenvironment that is essential for cellular functionality and regulation. However, during aging, the ECM undergoes significant changes along with the cellular components. The ECM constituents are over- or down-expressed, degraded, and deformed in senescence cells. ECM aging contributes to tissue dysfunction and failure of stem cell maintenance. Aging is the primary risk factor for prevalent diseases, and ECM aging is directly or indirectly correlated to it. Hence, rejuvenation strategies are necessitated to treat various age-associated symptoms. Recent rejuvenation strategies focus on the ECM as the basic biomaterial for regenerative therapies, such as tissue engineering. Modified and decellularized ECMs can be used to substitute aged ECMs and cell niches for culturing engineered tissues. Various tissue engineering approaches, including three-dimensional bioprinting, enable cell delivery and the fabrication of transplantable engineered tissues by employing ECM-based biomaterials.