Molecular and Biologic Effects of Platelet-Rich Plasma (PRP) in Ligament and Tendon Healing and Regeneration: A Systematic Review

Ultrasound-guided interventions in elite soccer players

In the world of elite soccer, or football as we call it in the UK, a player who cannot play for any length of time costs the team money and team performance. The time to return to play (RTP) is crucial in any player's career, and the use of ultrasound-guided ultrasound injections has become important in the management of injury. In this article, I will explain the importance of good practice when performing these procedures and the use of steroids, sodium hyaluronic acid, platelet-rich plasma (PRP), and other therapies in achieving the goal of decreasing the time of RTP for the footballer. KEY POINTS: •Injection therapies are routine practice in maintaining and treating soccer injuries. •Injection therapies can be safely performed under ultrasound guidance.

Development of hyaluronic acid-based hydrogels for chronic diabetic wound healing: A review

This research delves into the advancements in chronic skin wound treatment, with a particular focus on diabetic foot ulcers, utilizing hyaluronic acid (HA)-based hydrogels. Hyaluronic acid, an integral component of the skin's extracellular matrix, plays a crucial role in process such as inflammation, angiogenesis, and tissue regeneration. Due to their three-dimensional network structure, biocompatibility, hydrophilicity, and gas exchange capabilities, HA-based hydrogels are considered highly suitable for promoting wound healing. Nonetheless, pure HA hydrogels exhibit limitations including insufficient mechanical strength and rapid release of encapsulated substances. To address these limitations, the incorporation of bioactive materials such as chitosan and collagen was investigated. This combination not only optimized mechanical strength and degradation rates but also enhanced antibacterial and anti-inflammatory properties. Furthermore, responsive hydrogel dressings were developed to adapt to the specific characteristics of the diabetic wound microenvironment, enabling on-demand drug release. These advancements present new perspectives for the treatment of diabetic foot ulcers.

Systemic Rejuvenating Interventions: Perspectives on Neuroinflammation and Blood-Brain Barrier Integrity

The aging process results in structural, functional, and immunological changes in the brain, which contribute to cognitive decline and increase vulnerability to neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and stroke-related complications. Aging leads to cognitive changes and also affect executive functions. Additionally, it causes neurogenic and neurochemical alterations, such as a decline in dopamine and acetylcholine levels, which also impact cognitive performance. The chronic inflammation caused by aging contributes to the impairment of the blood-brain barrier (BBB), contributing to the infiltration of immune cells and exacerbating neuronal damage. Therefore, rejuvenating therapies such as heterochronic parabiosis, cerebrospinal fluid (CSF) administration, plasma, platelet-rich plasma (PRP), and stem cell therapy have shown potential to reverse these changes, offering new perspectives in the treatment of age-related neurological diseases. This review focuses on highlighting the effects of rejuvenating interventions on neuroinflammation and the BBB.

The effect of platelet-rich plasma on ferroptosis of nucleus pulposus cells induced by Erastin

Background

Intervertebral disc degeneration (IVDD) has been linked to ferroptosis, a type of programmed cell death. The role of platelet-rich plasma (PRP) in mitigating ferroptosis in nucleus pulposus (NP) cells within IVDD remains unclear.

Purpose

This study aims to verify the effectiveness of PRP in reducing ferroptosis in NP cells induced by Erastin.

Methods

Primary NP cells were isolated from SD rats, and a ferroptosis model was established using Erastin. PRP was prepared and applied to assess its impact on ferroptosis-related markers, including reactive oxygen species (ROS), iron content, and glutathione peroxidase 4 (GPX4). The effects of PRP on the ultrastructure of NP cells were also observed using transmission electron microscopy (TEM).

Results

PRP treatment significantly restored GPX4 levels (431.47 ± 4.70 ng/L vs. 69.70 ± 4.06 ng/L, P < 0.05), reduced ROS levels (45.06 ± 3.78 vs. 155.36 ± 3.56, P < 0.05), and decreased iron content (32.24 ± 096 μg/L vs. 59.25 ± 3.72 μg/L, P < 0.05) in ferroptotic NP cells compared to the sham group. Additionally, PRP significantly increased the expression levels of collagen Ⅱ (0.72 ± 0.02 vs. 0.33 ± 0.02, P < 0.05) and aggrecan (0.81 ± 0.01 vs. 0.31 ± 0.02, P < 0.05) compared to the sham group. TEM analysis also showed improvements in mitochondrial ultrastructure. These findings suggest that PRP can alleviate ferroptosis and promote cellular recovery.

Conclusions

The study demonstrates the potential of PRP as a therapeutic intervention in IVDD by mitigating ferroptosis in NP cells, offering a new theoretical basis for PRP treatment in degenerative disc diseases.

Editorial Commentary: Biologics Injections for Partial-Thickness Rotator Cuff Tears Show Promise

Partial-thickness rotator cuff tears (PTRCTs) are difficult to treat. Conservative treatment typically includes physical therapy, nonsteroidal anti-inflammatory drugs, and injectables (e.g., corticosteroid injections, hyaluronic acid, platelet-rich plasma [PRP], stem cells). Recent studies have demonstrated that PRP alone or in combination with other injectables (e.g., PRP + hyaluronic acid) provides a positive short-term therapeutic benefit in patients with PTRCTs. Yet, effects tend to diminish after 1 year. Up to 42% of patients with PTRCTs treated conservatively exhibit tear progression necessitating surgical intervention, and some research shows that PRP may inhibit tendon regeneration. The efficacy and safety of PRP preparations and concentrations can vary, and the optimal biologic injectable and formulation is unknown. Yet, preoperative corticosteroid injections can increase risk of infection after shoulder arthroscopy; thus, continued investigation of biologic injection for rotator cuff tears is indicated.

Use of platelet-rich plasma in rheumatic diseases

Platelet-rich plasma (PRP) has gained increasing recognition as a promising therapeutic agent in managing rheumatic diseases. Conventional treatments, including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and disease-modifying antirheumatic drugs (DMARDs), primarily act on reducing inflammation but fail to address the underlying mechanisms of connective tissue degradation. PRP, an autologous preparation enriched with growth factors and bioactive molecules, is pivotal in modulating inflammation and fostering tissue regeneration. This review overviews the therapeutic potential of PRP across a spectrum of rheumatic diseases, such as osteoarthritis (OA), rheumatoid arthritis (RA), systemic sclerosis (SSc), and osteonecrosis. The regenerative capacity of PRP, driven by vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and transforming growth factor-beta (TGF-β), promotes tissue repair, reduces cartilage damage and improves joint function. Emerging evidence supports the efficacy of PRP in early-stage OA, demonstrating superior outcomes over traditional therapies like hyaluronic acid and glucocorticoids in terms of pain relief and functional improvement. Despite its benefits, PRP therapy is characterized by variability in treatment responses, with challenges in standardizing preparation protocols and treatment regimens. This review highlights the need for robust clinical trials to establish uniform treatment protocols, optimize patient selection, and evaluate the long-term clinical outcomes of PRP therapy in rheumatic diseases.

A comparative analysis of platelet-rich plasma alone versus combined with extracorporeal shockwave therapy in athletes with patellar tendinopathy and knee pain: a randomized controlled trial

BACKGROUND

Patellar tendinopathy, also known as jumper's knee, can significantly impact the quality of daily life for patients due to the associated pain. A randomized controlled trial was investigated the clinical, sonographic, and serum cytokine markers in patellar tendinopathy of athletes following platelet-rich plasma (PRP) or PRP with extracorporeal shockwave therapy (ESWT) treatments. Our aims to investigate and compare therapeutic effects of PRP versus a combination of PRP with ESWT for treating patellar tendinopathy.

METHODS

A total of 33 athletes with patellar tendinopathy were randomized into two groups. PRP + Sham (PS) group received intraarticular injection of autologous PRP (5 mL) once and sham ESWT. PRP + ESWT (PE) group received intraarticular injection of autologous PRP once and after 1 week ESWT (0.2 mJ/mm2 energy flux density, 1350 impulses, 4 Hz) once. All patients were followed up for 1 year.

RESULTS

Autologous PRP injection and its combination with ESWT are both effective treatments for chronic patellar tendinopathy in athletes. PRP combined with ESWT resulted in faster reduction of knee pain than PRP alone at the 1-month follow-up. Serum IL-33 showed no significant difference at the 12-month follow-up. Levels of interleukin (IL)-6, IL-15, and IL-17 increased at the 12-month follow-up, potentially due to the additional training. However, the athletes did not report any discomfort or injuries, and no abnormalities were detected by ultrasonography after study. We demonstrated improvements in pain and functional scores, as well as knee injury protection in athletes, following 12 months of PRP and PRP with ESWT treatments.

CONCLUSIONS

The study analyzed the therapeutic effect of PRP injection alone and combining PRP injection with ESWT for chronic patellar tendinopathy. Our results showed that combined treatment can facilitate the pain relief early than PRP alone and is a safety treatment modality. No adverse effect was noted in our study. Trial registration Research registry and the registration number is researchregistry9518. Registered 14 September 2023. https://www.researchregistry.com/browse-the-registry#home/registrationdetails/650263e4f549fd00282a338c/ . The level of evidence is level II.

Hybrid, transarticular external fixation with platelet-rich plasma injection as a treatment for partial calcaneal tendon disruption in dogs without primary tenorrhaphy

OBJECTIVE

To report the use of a hybrid, transarticular external skeletal fixator and platelet-rich plasma injection without primary tenorrhaphy for management of partial calcanean tendon disruption in dogs.

STUDY DESIGN

Multi-institutional retrospective study.

ANIMALS

A total of 11 client-owned dogs.

METHODS

Medical records from two referral centers from 2019 to 2022 were reviewed for inclusion in the study. Dogs diagnosed with partial, non-traumatic calcanean tendon disruption treated with hybrid, transarticular external skeletal fixation and platelet-rich plasma injection were included in the study. Cases that did not include complete postoperative follow-up over 8-12 weeks and owner-reported outcomes at >6 months were excluded from the study. Dogs with traumatic laceration or those in which a primary tenorrhaphy was performed were also excluded.

RESULTS

A total of 11 (n = 11) dogs met the inclusion criteria. Median follow-up time was 18.5 months (6 months-34 months). Mean time of fixation was 9 weeks (6 weeks-12 weeks). Five dogs returned to full, pain-free function (5/11 = 45%). Five dogs had an acceptable return to function (5/11 = 45%). One dog had an unacceptable outcome (1/11 = 9%). Pin tract complications occurred in five dogs (5/11 = 45%) and resolved with medical intervention.

CONCLUSION

The results of this study suggest that temporary tibiotarsal immobilization with a hybrid, transarticular external skeletal fixator and platelet-rich plasma injection without primary tenorrhaphy can lead to a successful outcome in dogs with partial calcanean tendon disruption.

CLINICAL SIGNIFICANCE

Temporary hybrid, transarticular external skeletal fixation and platelet-rich plasma injection without primary tenorrhaphy may play a role in the management of partial calcanean tendon disruption in dogs.

An injectable self-lubricating supramolecular polymer hydrogel loaded with platelet lysate to boost osteoarthritis treatment

Globally, osteoarthritis (OA) is the most prevalent joint disease and is characterized by infiltration of M1 macrophages in the synovium, anabolic-catabolic imbalance of the extracellular matrix (ECM), increased articular shear force and overproduction of reactive oxygen species (ROS). Disease-modifying OA drugs are not yet available, and treatments for OA focus solely on reducing pain and inflammation and have limited therapeutic effect. Herein, we developed an injectable self-lubricating poly(N-acryloyl alaninamide) (PNAAA) hydrogel loaded with platelet lysate (PL) (termed "PNAAA@PL") for treating OA. Tribological and drug release tests revealed suitable lubrication properties and sustained release of bioactive factors in PNAAA@PL. In vitro experiments showed that PNAAA@PL alleviated interleukin-1β (IL-1β)-induced anabolic-catabolic imbalance of chondrocytes and repolarized pro-inflammatory M1 macrophages to the anti-inflammatory M2 phenotype via intracellular ROS scavenging. Additionally, the PNAAA@PL hydrogel enhanced the migratory capacity and chemotaxis ability of stem cells, which are essential for chondrogenesis. In vivo, the functionalized PNAAA@PL hydrogel acted like synovial fluid following intra-articular injection into a rat OA model with anterior cruciate ligament transection, ultimately attenuating cartilage degeneration and synovitis. According to molecular mechanism studies, PNAAA@PL repairs cartilage in the OA model by inhibiting the NF-ĸB pathway. Overall, this self-lubricating PNAAA@PL hydrogel offers a comprehensive strategy for preventing OA progression by engineering a biophysiochemical microenvironment to generate high-quality hyaline cartilage.

The Biological Effect of Platelet-Rich Plasma on Rotator Cuff Tears: A Prospective Randomized In Vivo Study

The positive effect of platelet-rich plasma (PRP) on tendon metabolism has been extensively investigated and proven in vitro. Additionally, in vivo animal studies have correlated the application of PRP with the enhancement of tenocyte anabolic activity in the setting of tendon degeneration. However, less is known about its in vivo effect on human tendon biology. The purpose of the current prospective randomized comparative study was to evaluate the effect of PRP on torn human supraspinatus tendon. Twenty consecutive eligible patients with painful and magnetic resonance imaging (MRI)-confirmed degenerative supraspinatus tendon tears were randomized in a one-to-one ratio into two groups. The patients in the experimental group (n = 10) underwent an ultrasound-guided autologous PRP injection in the subacromial space 6 weeks before the scheduled operation. In the control group (n = 10), no injection was made prior to surgery. Supraspinatus tendon specimens were harvested from the lateral end of the torn tendon during shoulder arthroscopy and were evaluated under optical and electron microscopy. In the control group, a mixed cell population of oval and rounded tenocytes within disorganized collagen and sites of accumulated inflammatory cells was detected. In contrast, the experimental group yielded abundant oval-shaped cells with multiple cytoplasmic processes within mainly parallel collagen fibers and less marked inflammation, simulating the intact tendon structure. These findings indicate that PRP can induce microscopic changes in the ruptured tendon by stimulating the healing process and can facilitate a more effective recovery.

The Effectiveness of Treating Osgood-Schlatter Disease (OSD) with Leukocyte-Rich Platelet-Rich Plasma (LR-PRP) Depending on the Duration of the Disease

Background: Osgood-Schlatter disease (OSD) occurs mainly in physically active adolescents, causing significant physical activity restrictions. The aim of this study is to compare the effectiveness of treating OSD with leukocyte-rich platelet-rich plasma (LR-PRP) depending on the duration of the disease and to attempt to develop an alternative treatment method to the currently used conservative therapy. Methods: Treatment efficacy was evaluated using the VAS, Tegner, Lysholm, and KOOS scales. Subject satisfaction, return to sports activity, potential adverse effects, and X-ray evaluation were likewise used to assess the success of the procedure. Results: Analysis across all scales showed statistically significant treatment effectiveness with LR-PRP in both groups of patients. When comparing the two groups, significantly better treatment outcomes were achieved in the acute phase of OSD. Treatment satisfaction in the acute OSD group was 95%, compared to 64% in the chronic group. The MCID value after LR-PRP injection in acute OSD compared to chronic OSD reached 100% vs. 81% on the VAS scale, 95.5% vs. 55% on the Tegner scale, 95% vs. 47% on the Lysholm scale and 91% vs. 27% on the KOOS scale. No adverse effects were recorded in either group. Conclusions: The high efficacy of LR-PRP treatment in patients with acute OSD, in correlation with high safety, as well as rapid and lasting results, can be an effective and beneficial alternative to conservative treatment. This single procedure seems particularly justified in a group of young professional athletes, where absence from training can lead to serious consequences.

Evaluation of Patellar Tendon Structural Changes following Biological Treatments: Secondary Analysis of Double-Blinded Clinical Trial of Bone Marrow Mesenchymal Stromal Cells and Leukocyte-Poor Platelet-Rich Plasma

Objective quantification of tendon structural changes through imaging is only achieved by evaluating tendon structure using ultrasound tissue characterization (UTC) technology. This study compares the effects of bone marrow mesenchymal stromal cells (BM-MSC) and leukocyte-poor platelet-rich plasma (Lp-PRP) on tendon structure and clinical outcomes in male patients with patellar tendinopathy measured with UTC at 3, 6, and 12 months after treatment. This is a double-blinded clinical trial with a randomized active control study with 20 male patients diagnosed with patellar tendinopathy who underwent BM-MSC and Lp-PRP. Bilateral ultrasound tissue characterization scans of the patellar tendon were carried out after 3, 6, and 12 months, as well as tests for strength and pain. UTC patellar tendon was analyzed at the insertion, proximal, and mid-tendon. BM-MSC showed a greater capacity to promote further positive changes than Lp-PRP. Lp-PRP presented higher disorganized echo-type II in the mid-tendon (p = 0.04; ES = 1.06) and III (p = 0.02; ES = -1.47) after 3 months in the Lp-PRP group. Similar results were seen after 6 and 12 months. Pain and strength data show improvement in the treated tendon. BM-MSC treatment demonstrates a superior capacity to promote tendon regeneration and organization, restore strength, and reduce pain compared to Lp-PRP, after 3, 6, and 12 months in male patients with patellar tendinopathy.

Cytoprotective Effect of Growth Factors Derived From Platelets on Corticosteroid-Treated Primary Anterior Cruciate Ligament-Derived Stromal Cells and Chondrocytes

Background The use of corticosteroids, such as methylprednisolone, for pain management is a common clinical practice. However, it is well known that corticosteroids induce toxicity in anterior cruciate ligament (ACL)-derived stromal cells and chondrocytes. Growth factors from platelets have anti-inflammatory effects that can potentially limit the cytotoxic effects of corticosteroids. In this study, we explored the role of growth factors obtained from the OssinextTM kit (commercially available Wockhardt growth factor concentrate (GFC) kit) in recovering methylprednisolone-induced cell damage. Methodology Primary ACL-derived stromal cells and chondrocytes were isolated from human ligament tissue and articular cartilage, respectively, and characterized by immunophenotyping, gene expression analysis, and immunostaining. GFC obtained from OssinextTM kit was used for the experiments. The ACL-derived stromal cells and chondrocytes were treated with methylprednisolone, alone or in combination with GFC. Cell viability was measured by the neutral red uptake assay. Changes in cell morphology and collagen pattern were observed microscopically by H&E staining and immunostaining, respectively. Cell proliferation was assessed by cell migration assay, and the cell ultra-structure was analyzed using transmission electron microscopy. Results Methylprednisolone was found to induce cytotoxicity, altered cell morphology, reduced cell proliferation, and organelle damage in both ACL-derived stromal cells and chondrocytes. GFC obtained from the OssinextTM kit was able to restore cell viability and reverse the cell structure damages induced by methylprednisolone. GFC was found to recover and protect the cells, both when used in combination with steroids and when used after the steroid treatment. Conclusions The results indicate that GFC may be clinically beneficial when used in combination with steroids to mitigate their adverse effects.

Diagnostic value of measuring the talofibular space using stress sonography in chronic lateral ankle instability

OBJECTIVES

To investigate the diagnostic value of measuring the talofibular space using stress sonography for chronic lateral ankle instability (CLAI).

MATERIALS & METHODS

We recruited patients who were clinically diagnosed with CLAI between October 2018 and December 2019 (CLAI group). A control group of healthy volunteers was also included for this study. Both groups underwent a preliminary stress sonographic examination. First, the ultrasonic characteristics of the anterior talofibular ligament (ATFL), including length, thickness, relaxation, calcification, and rupture, were observed using conventional sonography. Second, the talofibular space at the passive neutral position (D1) and maximum varus position (D2) was measured (by stress sonographic images), and the difference (ΔD = D1-D2) between them was determined. Third, the parameters of the two groups were statistically compared. Finally, receiver operating characteristic (ROC) curves and area under the curve (AUC) analyses were performed for parameters with significant differences.

RESULTS

The CLAI group comprised 60 patients, yielding data on 60 ankles, whereas the control group comprised 35 participants, yielding data for 70 ankles. Differences in D1, D2, and ΔD of the talofibular space between the two groups were significant, with ΔD proving to be the best diagnostic indicator (P < 0.001). Its AUC, optimal cutoff value, sensitivity, and specificity were 0.922, 0.11 cm, 73 %, and 94 %, respectively, followed by D2 (0.850, 0.47 cm, 67 %, and 94 %, respectively; P < 0.001) and D1 (0.635, 0.47 cm, 67 %, and 94 %, respectively; P = 0.006).

CONCLUSION

Measurement of talofibular space in stress sonography is a valuable diagnostic indicator for CLAI, especially the ΔD between the neutral and stress position.

From Dugout to the Mound: A Tale of Platelet-Rich Performance

Ulnar collateral ligament (UCL) tears of the elbow are prevalent injuries among throwing athletes and are associated with excessive or repeated valgus forces at the elbow. We present the case of an 18-year-old male baseball pitcher with an 18-month history of progressive right elbow pain, notably worsened during his fastball pitching. Clinical assessment revealed tenderness with dynamic stressing of the right UCL. Imaging analyses, including magnetic resonance imaging (MRI) and dynamic ultrasound, confirmed a high-grade partial tear of the UCL at its origin. Non-operative management was pursued, which included an ultrasound-guided platelet-rich plasma (PRP) injection and intensive physical therapy. Follow-up evaluations at six and 12 weeks demonstrated a noteworthy improvement in subjective pain descriptions and structural healing of the UCL. After the patient completed a therapy and rehabilitation program, throwing activities at full strength were able to be resumed. This case underscores the potential efficacy of conservative approaches in handling UCL tears with the inclusion of PRP as a viable treatment option.

Strategic analysis of body composition indices and resting platelet ATP levels in professional soccer players for better platelet-rich plasma therapy

Background: Autologous platelet-rich plasma (PRP) therapy is ambiguously thought to be more effective in elite athletes than in sedentary patients, although the possible importance of recipient responsiveness remains poorly understood. To address this issue, along with the well-known PRP quality, in this initial study, we evaluated two candidate biomarkers: body composition indices (BCIs), which reflect systemic physical conditions, and resting platelet ATP levels, which reflect platelet energy expenditure and the mass of energy generation units. Methods: In this cross-sectional cohort study, blood samples were collected from male professional soccer players (PSPs) on a local professional team during the off-season and platelet ATP levels were quantified using an ATP luminescence assay kit. BCIs were measured using the body mass impedance method. Age-matched male sedentary participants were used as the controls. Results: Among the BCIs, the body mass index, basal metabolic rate (BMR), and skeletal muscle weight levels were higher in the PSPs than in the controls. The platelet ATP levels in the PSPs group were significantly lower than those in the control group. The correlation between BMR and platelet ATP levels was moderately negative in the control group, but weakly positive in the PSPs group. Conclusion: Owing to regular physical exercise, PSPs had higher BMR levels and lower platelet ATP levels without a significant mutual correlation compared to sedentary controls. This study did not indicate the influence of these biomarkers on the success of PRP therapy but provided evidence for a better understanding of PRP therapy, particularly for elite athletes.

Local injection therapy in the complex treatment of musculoskeletal disorders: principles of application, evidence base, safety

Local injection therapy (LIT)  is an important component of the complex treatment of musculoskeletal disorders (MSD), which is widely used in real clinical practice. Glucocorticoids, hyaluronic acid drugs (HA), autologous cell drugs, botulinum toxin type A, radioactive isotopes, etc. are used for LIT.  LIT makes it possible to achieve a pronounced symptomatic effect, while in some cases, for example, repeated HA treatments in patients with osteoarthritis, the possibility of slowing the progression of the disease and reducing the need for surgical treatment is discussed.

The performance of LIT requires special skills and abilities of the physician, careful compliance with the rules of asepsis and antisepsis, and instrumental visualization. LIT can be associated with serious complications and therefore must be performed according to strict indications.

The Expert Council was devoted to defining the basic principles of LIT. The indications for the use of certain types of this therapies, the evidence base for its efficacy and safety, the order of application of different drugs, and the need to combine LIT with other drug and non-drug treatments of MSD were reviewed.

Hyaluronic acid-based dual network hydrogel with sustained release of platelet-rich plasma as a diabetic wound dressing

In recent years, the incidence of diabetic skin ulcers has increased. Because of its extremely high disability and fatality rate, it brings a huge burden to patients and society. Platelet-rich plasma (PRP) contains a large number of biologically active substances and is of great clinical value in the treatment of various wounds. However, its weak mechanical properties and the consequent abrupt release of active substances greatly limit its clinical application and therapeutic efficacy. Here, we chose hyaluronic acid (HA) and ε-polylysine (ε-PLL) to prepare a hydrogel with the ability to prevent wound infection and promote tissue regeneration. At the same time, using the macropore barrier effect of the lyophilized hydrogel scaffold, platelets in PRP are activated with calcium gluconate in the macropores of the scaffold carrier, and fibrinogen from PRP is converted in a fibrin-packed network forming a gel that interpenetrates the hydrogel scaffold carrier, thus creating a double network hydrogel with slow-release of growth factors from degranulated platelets. The hydrogel not only showed better performance in functional assays in vitro, but also showed more superior therapeutic effects in reducing inflammatory response, promoting collagen deposition, facilitating re-epithelialization and angiogenesis in the treatment of full skin defects in diabetic rats.

Role of platelet-rich plasma in the treatment of rotator cuff tendinopathy

Shoulder pain is a common musculoskeletal complaint, and rotator cuff (RC) pathologies are one of the main causes. The RC undergoes various tendinopathic and avascular changes during the aging process. Other degenerative changes affecting its healing potential make it an appealing target for biological agents. Platelet-rich plasma (PRP) has demonstrated the potential to deliver a high concentration of several growth factors and anti-inflammatory mediators, and its clinical use is mainly supported by experiments that demonstrated its positive effect on muscle, ligaments, and tendinous cells. This review aimed to specify the role of PRP and its future applications in RC tendinopathies based on the current clinical evidence. Due to the different characteristics and conflicting outcomes, clinicians should use PRP with moderate expectations until more consistent evidence is available. However, it is reasonable to consider PRP in patients with contraindications to corticosteroid injections or those with risk factors for inadequate healing. Its autologous origin makes it a safe treatment, and its characteristics make it a promising option for treating RC tendinopathy, but the efficacy has yet to be established.

Network proteomic analysis identifies inter-alpha-trypsin inhibitor heavy chain 4 during early human Achilles tendon healing as a prognostic biomarker of good long-term outcomes

The suboptimal or protracted regeneration of injured connective tissues often results in significant dysfunction, pain, and functional disability. Despite the prevalence of the condition, few studies have been conducted which focused on biomarkers or key molecules involved in processes governing healing outcomes. To gain insight into injured connective tissue repair, and using the Achilles tendon as a model system, we utilized quantitative proteomic and weighted co-expression network analysis of tissues acquired from Achilles tendon rupture (ATR) patients with different outcomes at 1-year postoperatively. Two modules were detected to be associated with prognosis. The initial analysis identified inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) as a biomarker or hub protein positively associated with better healing outcomes. Additional analysis identified the beneficial role of ITIH4 in inflammation, cell viability, apoptosis, proliferation, wound healing, and for the synthesis of type I collagen in cultured fibroblasts. Functionally, the effects of ITIH4 were found to be mediated by peroxisome proliferator-activated receptor gamma (PPARγ) signaling pathways. Taken together, these findings suggest that ITIH4 plays an important role in processes of connective tissue repair and advocate for the potential of ITIH4 as a therapeutic target for injured connective tissue repair.

Trial registration

http://clinicaltrials.gov, identifiers NCT02318472, NCT01317160.