What do we mean by the term "inflammation"? A contemporary basic science update for sports medicine

Widespread Vascularization and Correlation of Glycosaminoglycan Accumulation to Tendon Pain in Human Plantar Fascia Tendinopathy

BACKGROUND

Plantar fasciitis is a painful tendinous condition (tendinopathy) with a high prevalence in athletes. While a healthy tendon has limited blood flow, ultrasound has indicated elevated blood flow in tendinopathy, but it is unknown if this is related to a de facto increase in the tendon vasculature. Likewise, an accumulation of glycosaminoglycans (GAGs) is observed in tendinopathy, but its relationship to clinical pain is unknown.

PURPOSE

To explore to what extent vascularization, inflammation, and fat infiltration were present in patients with plantar fasciitis and if they were related to clinical symptoms.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Biopsy specimens from tendinopathic plantar fascia tissue were obtained per-operatively from both the primary site of tendon pain and tissue swelling ("proximal") and a region that appeared macroscopically healthy at 1 to 2 cm away from the primary site ("distal") in 22 patients. Biopsy specimens were examined with immunofluorescence for markers of blood vessels, tissue cell density, fat infiltration, and macrophage level. In addition, pain during the first step in the morning (registered during an earlier study) was correlated with the content of collagen and GAGs in tissue.

RESULTS

High vascularization (and cellularity) was present in both the proximal (0.89%) and the distal (0.96%) plantar fascia samples, whereas inconsistent but not significantly different fat infiltration and macrophage levels were observed. The collagen content was similar in the 2 plantar fascia regions, whereas the GAG content was higher in the proximal region (3.2% in proximal and 2.8% in distal; P = .027). The GAG content in the proximal region was positively correlated with the subjective morning pain score in the patients with tendinopathy (n = 17).

CONCLUSION

In patients with plantar fasciitis, marked tissue vascularization was present in both the painful focal region and a neighboring nonsymptomatic area. In contrast, the accumulation of hydrophilic GAGs was greater in the symptomatic region and was positively correlated with increased clinical pain levels in daily life.

CLINICAL RELEVANCE

The accumulation of GAGs in tissue rather than the extent of vascularization appears to be linked with the clinical degree of pain symptoms of the disease.

Anatomic characteristics of shoulder based on MRI accurately predict incomplete rotator cuff injuries in patients: relevance for predictive, preventive, and personalized healthcare strategies

Background and PPPM-related working hypothesis

In the diagnosis of incomplete rotator cuff injuries (IRCI), magnetic resonance imaging (MRI) and ultrasound examination often have false-positive and false-negative results, while arthroscopy is expensive, invasive, and complex. From the strategy of predictive, preventive, and personalized medicine (PPPM), shoulder anatomical characteristics based on MRI have been demonstrated to accurately predict IRCI and their clinical applicability for personalized prediction of IRCI.

Aims

This study aimed to develop and validate a nomogram based on anatomical features of the shoulder on MRI to identify IRCI for PPPM healthcare strategies.

Methods

The medical information of 257 patients undergoing preoperative MRI examination was retrospectively reviewed and served as the primary cohort. Partial-thickness rotator cuff tears (RCTs) and tendinopathy observed under arthroscopy were considered IRCI. Using logistic regression analyses and least absolute shrinkage and selection operator (LASSO), IRCI was identified among various preoperative factors containing shoulder MRI and clinical features. A nomogram was constructed and subjected to internal and external validations (80 patients).

Results

The following eight independent risk factors for IRCI were identified:AgeThe left injured sidesThe Goutallier classification of supraspinatus in oblique coronal positionThe Goutallier classification of supraspinatus in the axial positionAcromial thicknessAcromiohumeral distanceCoracohumeral distanceAbnormal acromioclavicular joint signalsThe nomogram accurately predicted IRCI in the development (C-index, 0.932 (95% CI, 0.891, 0.973)) and validation (C-index, 0.955 (95% CI, 0.918, 0.992)) cohorts. The calibration curve was consistent between the predicted IRCI probability and the actual IRCI ratio of the nomogram. The decision curve analysis and clinical impact curves demonstrated that the model had high clinical applicability.

Conclusions

Eight independent factors that accurately predicted IRCI were determined using MRI anatomical findings. These personalized factors can prevent unnecessary diagnostic interventions (e.g., arthroscopy) and can assist surgeons in implementing individualized clinical decisions in medical practice, thus addressing the goals of PPPM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00333-5.

Advances in the Clinical Application of Platelet-Rich Plasma in the Foot and Ankle: A Review

Autologous and recombinant biologic substances have been generated as a result of the research into the cellular features of the healing process. Orthobiologics are increasingly being used in sports medicine and musculoskeletal surgery. Nevertheless, clinical data are limited; consequently, further studies are required, particularly in foot and ankle pathologies. This review aims to provide evidence of the most recent literature results and ignite the interest of orthopedic specialists eager for an update about the most current discussion on platelet-rich plasma (PRP) clinical applications in the foot and ankle fields. Previous studies have shown that platelet-rich plasma can be beneficial in treating various conditions, such as chronic foot ulcers, osteoarthritis, Achilles tendinopathy, etc. Despite the positive effects of PRP on various musculoskeletal conditions, more prospective studies are needed to confirm its effectiveness at treating ankle and foot pathologies. In addition to clinical trials, other factors, such as the quality of the research and the procedures involved, must be considered before they can be used in patients. More long-term evaluations are needed to support or oppose its application in treating foot and ankle disorders. We present the most extensive review of PRP's clinical applications in the foot and ankle field.

Standardization and validation of a conventional high yield platelet-rich plasma preparation protocol

BACKGROUND

Of late, numerous randomised controlled trials report platelet-rich plasma (PRP) to be ineffective with preparation protocols of low platelet yield despite using expensive commercial PRP kits.

OBJECTIVE

This study aims to identify and standardize a preparation protocol for PRP with maximum platelets yield and concentration to obtain favourable results without the use of commercial preparation kits.

MATERIALS & METHODS

Blood samples were collected from 40 healthy volunteers who signed informed consent for participation in the study. The double spin protocol of PRP preparation was analyzed for variables such as centrifugal acceleration, time, and volume of blood processed and final product utilized. The final PRP prepared was investigated for platelet recovery, concentration, integrity, and viability. Each protocol investigated with technical and biological duplicates to avoid reporting and sampling bias.

RESULTS

We noted maximum platelet recovery (86-99%) with a consistent 6.4 ± 0.8 times the baseline concentration of platelets with first centrifugation at 100g for 15 min followed by second centrifugation at 1600g for 20 min. We did not note a loss of integrity or viability of the platelets in the final product from the above-said protocol. We also validated the protocol among all the study participants demonstrating consistency.

CONCLUSION

The preparation of PRP by the double-spin protocol using 10 ml of blood at 100 g followed by 1600 g for 15 and 20 min respectively in a 15 ml tube and using the lower 1/3rd of the final product demonstrated consistent high platelet recovery (86-99%) and concentration (6x) without disturbing the platelet integrity or viability.

Bio-orthogonal Click Chemistry Methods to Evaluate the Metabolism of Inflammatory Challenged Cartilage after Traumatic Overloading

During traumatic joint injuries, impact overloading can cause mechanical damage to the cartilage. In the following inflammation phase, excessive inflammatory cytokines (e.g., interleukin-1β (IL-1β)) can act on chondrocytes, causing over-proliferation, apoptosis, and extracellular matrix (ECM) degradation that can lead to osteoarthritis. This study investigated the combined effects of traumatic overloading and IL-1β challenge on the metabolic activities of chondrocytes. Bovine cartilage explants underwent impact overloading followed by IL-1β exposure at a physiologically relevant dosage (1 ng/mL). New click chemistry-based methods were developed to visualize and quantify the proliferation of in situ chondrocytes in a nondestructive manner without the involvement of histological sectioning or antibodies. Click chemistry-based methods were also employed to measure the ECM synthesis and degradation in cartilage explants. As the click reactions are copper-free and bio-orthogonal, i.e., with negligible cellular toxicity, cartilage ECM was cultured and studied for 6 weeks. Traumatic overloading induced significant cell death, mainly in the superficial zone. The high number of dead cells reduced the overall proliferation of chondrocytes as well as the synthesis of glycosaminoglycan (GAG) and collagen contents, but overloading alone had no effects on ECM degradation. IL-1β challenge had little effect on cell viability, proliferation, or protein synthesis but induced over 40% GAG loss in 10 days and 61% collagen loss in 6 weeks. For the overloaded samples, IL-1β induced greater degrees of degradation, with 68% GAG loss in 10 days and 80% collagen loss in 6 weeks. The results imply a necessary immediate ease of inflammation after joint injuries when trauma damage on cartilage is present. The new click chemistry methods could benefit many cellular and tissue engineering studies, providing convenient and sensitive assays of metabolic activities of cells in native three-dimensional (3D) environments.

Evaluation of the treatment of fever, pain and inflammation with Indigofera suffruticosa Miller Leaves Aqueous Extract

ETHNOPHARMACOLOGICAL RELEVANCE

Indigofera suffruticosa has reports of its popular use for analgesy in several cultures. Besides that, all parts of this plant are used for some medicinal outcome. The leaves are used in teas, decoctions, juices and included in baths for treating fever and inflammatory processes.

AIM OF THE STUDY

To evaluate the anti-inflammatory activity mechanisms of I. suffruticosa leave aqueous extract (IsAE).

MATERIALS AND METHODS

Phytochemical screening of IsAE was performed by thin layer chromatography. Total flavonoid content was determined and expressed by milligram of quercetin equivalent per gram of extract (mgEQ/g). 50% of the lethal dose that kills animals (LD₅₀) was determined by acute toxicity in mice. Anti-inflammatory activity was evaluated through carrageenan-induced paw edema, peritonitis, and protein denaturation inhibition. Anti-nociceptive potential was evaluated by acetic acid-induced writhing and formalin tests. Antipyretic activity was assessed by yeast-induced fever.

RESULTS

Phytochemical analysis revealed the presence of flavonoids and acid gallic in a quantity of 33.9 mg QE/g. Acute toxicity evaluation resulted in a LD₅₀ of 3807.88 mg/kg. For carrageenan-induced paw edema test, IsAE in both doses (20 and 100 mg/kg) reduced the edema in 83.93%. IsAE reduced nitric oxide (NO) production and leucocytes migration to peritonitis inflammation site and at a concentration of 0.5 mg/mL showed also inhibition of protein denaturation similar to indomethacin in the same concentration. IsAE inhibited in 72.60% the number of contortions in writhing test. In formalin test, IsAE was also efficient, but showed results only in the second phase. In addition, the concentration of 100 mg/kg reduced fever significantly.

CONCLUSIONS

IsAE proved to be anti-inflammatory, acting in different parts of the inflammation process, confirming its popular use.

Mesenchymal stem cells have ameliorative effect on the colitis model via Nrf2/HO-1 pathway

Purpose:

To evaluate the ameliorative effect of mesenchymal stem cells (MSCs) on acetic acid colitis model via Nrf2/HO-1 pathway in rats.

Methods:

In this study, 30 rats were divided into three groups. Acute colitis was induced by rectal administration of 4% solution of acetic acid. MSCs were injected intraperitoneally in the treatment group.

Results:

Increased levels of tumor necrosis factor-α (TNF-α), pentraxin-3, and malondialdehyde (MDA) in colitis group were revealed biochemically. Increased level of TNF-α and decreased levels of Nrf2 and interleukin-10 (IL-10) were observed in rectum tissues. Increased fibrous tissue proliferation, vascularization and inflammatory cell infiltration were described in the colitis group. Significant improvement was observed in MSCs treated group histopathologically. Increased immunopositivity of TNF-α, vascular endothelial growth factor (VEGF) and CD68 markers was observed in the colitis group cells, and decreased level of this positivity was observed in MSCs treated group.

Conclusions:

Biochemical, histopathological and immunohistochemical results strongly support the ameliorative effect of MSCs against acetic induced colitis model via Nrf2/HO-1 pathway in rats.

Minor Soft Tissue Injuries may need PEACE in the Acute Phase, but Moderate and Severe Injuries Require CARE

For the past 30 years, conflicting and confusing theories have abounded for the acute-stage treatment of musculoskeletal injuries due to a lack of sufficient, high-quality research that substantiates an ideal approach. The main controversy concerns the use of cryotherapy. While cryotherapy has become established as a vital component of the initial treatment of musculoskeletal injuries as part of the rest, ice, compression and elevation (RICE) approach (Mirkin and Hoffman, 1978), doubts about its efficacy have arisen in recent years. In fact, the latest proposal is to use the protection, elevation, avoid, compression and education (PEACE) approach as acute-stage treatment of musculoskeletal injuries (Dubois and Esculier, 2020). This involves protection and elevation of the injured limb, avoidance of anti-inflammatory drugs and cryotherapy, compression of the injured limb and patient education.

Does Obesity Affect the Severity of Exercise-Induced Muscle Injury?

This literature review investigates the effects of obesity on exercise-induced muscle injury and reexamines the potential mechanisms of exercise-induced muscle injury related to obesity. Several studies reported that high body mass index and percent body fat can significantly affect the markers of muscle injury after exercise, including maximal strength, delayed onset muscle soreness, creatinine kinase level, and myoglobin level. The potential mechanisms resulting in these outcomes include structural changes in the cell membrane induced by high fat levels, increased inflammatory responses due to adipose tissues, reduced muscle satellite cell activation and myogenesis due to lipid overload, differences in muscle fiber distributions, and sedentary behaviors. These mechanisms, however, must be verified through more research. As obesity is a potential risk factor increasing the severity of exercise-induced muscle injuries, the exercise intensity and duration for obese patients must be carefully selected, and a preconditioning intervention (e.g., low-intensity eccentric training) may be considered before or during the early stages of the exercise program.

Is it time to put traditional cold therapy in rehabilitation of soft-tissue injuries out to pasture?

Cold therapy has been used regularly as an immediate treatment to induce analgesia following acute soft-tissue injuries, however, a prolonged ice application has proved to delay the start of the healing and lengthen the recovery process. Hyperbaric gaseous cryotherapy, also known as neurocryostimulation, has shown the ability to overcome most of the limitations of traditional cold therapy, and meanwhile promotes the analgesic and anti-inflammatory effects well, but the current existing studies have shown conflicting results on its effects. Traditional cold therapy still has beneficial effect especially when injuries are severe and swelling is the limiting factor for recovery after soft-tissue injuries, and therefore no need to be entirely put out to pasture in the rehabilitation practice. Strong randomized controlled trials with good methodological quality are still needed in the future to evaluate the effects of different cryotherapy modalities.

Anti-inflammatory effect of different PRGF formulations on cutaneous surface

Cutaneous autoimmune and inflammatory diseases are a major burden of global disease and many lack effective treatments that can derive in different dermatoses like atopic dermatitis. Despite the increase prevalence and the high health-care costs worldwide, the heterogeniety and multifactoriality of these diseases mean that effective treatment options are scarce. Plasma rich in growth factors (PRGF) technology could be an alternative approach that may help in the management of this cutaneous condition. The aim of this study was to assess the effect of two different PRGF formulations (just activated and autologous topical serum (ATS)) for the management of skin inflammation. Additionally, ATS was assessed over two patients suffering from radiotherapy induced dermatitis. Human organotypic skin explant cultures (hOSECs) were used as human skin models. To induce atopic dermatitis-like conditions, skin explants were treated with both interleukin-4 (IL-4) and interleukin-13 (IL-13). PRGF and ATS were intradermally and topically applied, respectively. Metabolic activity, reactive oxigen species (ROS), necrosis and inflammatory cytokine production were determined. Both PRGF formulations increased tissue viability and significantly reduced the excessive free radical accumulation and the cutaneous cytokine production such as TNF-α and IL-1β. Case reports showed a positive response after ATS treatment in terms of skin quality improvement, local erythema decrease and burning and itching amelioration. The oedema, swelling and desquamation caused by radiation induced dermatitis was also reduced and the patients referred ceased pruritus and pain. This preliminary study suggests that PRGF might aid in the management of inflammatory skin conditions.

Platelet-Rich Plasma Applications for Achilles Tendon Repair: A Bridge between Biology and Surgery

Achilles tendon ruptures are very common tendon ruptures and their incidence is increasing in modern society, resulting in work incapacity and months off sport, which generate a need for accelerated and successful therapeutic repair strategy. Platelet-rich plasma (PRP) is emerging as adjuvant human blood-derived constructs to assist Achilles tendon rupture treatment. However, myriad PRP preparation methods in conjunction with poor standardization in the modalities of their applications impinge on the consistent effectiveness of clinical and structural outcomes regarding their therapeutic efficacy. The purpose of this review is to provide some light on the application of PRP for Achilles tendon ruptures. PRP has many characteristics that make it an attractive treatment. Elements such as the inclusion of leukocytes and erythrocytes within PRP, the absence of activation and activation ex vivo or in vivo, the modality of application, and the adjustment of PRP pH can influence the biology of the applied product and result in misleading therapeutic conclusions. The weakest points in demonstrating their consistent effectiveness are primarily the result of myriad PRP preparation methods and the poor standardization of modalities for their application. Selecting the right biological scaffold and applying it correctly to restitutio ad integrum of ruptured Achilles tendons remains a daunting and complex task.

Proteomic analysis of platelet-rich and platelet-poor plasma

Background

Autologous blood products, such as platelet-rich plasma (PRP) are commercial products broadly used to accelerate healing of tissues after injuries. However, their content is not standardized and significantly varies in composition, which may lead to differences in clinical efficacy. Also, the underlying molecular mechanisms for therapeutic effects are not well understood.

Purpose

A proteomic study was performed to compare the composition of low leukocyte PRP, platelet poor plasma (PPP), and blood plasma. Pathway analysis of the proteomic data was performed to evaluate differences between plasma formulations at the molecular level. Low abundance regulatory proteins in plasma were identified and quantified as well as cellular pathways regulated by those proteins.

Methods

Quantitative proteomic analysis, using multiplexed isotopically labeled tags (TMT labeling) and label-free tandem mass spectrometry, was performed on plasma, low leukocyte PRP, and PPP. Plasma formulations were derived from two blood donors (one donor per experiment). Pathway analysis of the proteomic data identified the major differences between formulations.

Results

Nearly 600 proteins were detected in three types of blood plasma formulations in two experiments. Identified proteins showed more than 50% overlap between plasma formulations. Detected proteins represented more than 100 canonical pathways, as was identified by pathway analysis. The major pathways and regulatory molecules were linked to inflammation.

Conclusion

Three types of plasma formulations were compared in two proteomic experiments. The most represented pathways, such as Acute Phase Response, Coagulation, or System of the Complement, had many proteins in common in both experiments. In both experiments plasma sample sets had the same direction of biochemical pathway changes: up- or down-regulation. The most represented biochemical pathways are linked to inflammation.

Intermittent hypoxia induces turbinate mucosal hypertrophy via upregulating the gene expression related to inflammation and EMT in rats

PURPOSE

Chronic intermittent hypoxia (IH) plays a pivotal role in the consequences of obstructive sleep apnea (OSA). It has been demonstrated that IH impairs nasomaxillary complex growth to reduce nasal airway cavity size in rodent models. Although turbinate dysfunction with inflammatory mucosal hypertrophy is related to OSA, the role of IH in turbinate hypertrophy with inflammation-driven fibrosis is unknown. Here, we aimed to clarify the pathogenesis of inflammatory mucosal hypertrophy and epithelial-mesenchymal transition (EMT) in the nasal turbinate under IH.

METHODS

Seven-week-old male Sprague-Dawley rats were exposed to IH (4% O₂ to 21% O₂ with 0% CO₂) at a rate of 20 cycles/h.

RESULTS

Hypertrophy of the turbinate mucosa occurred after 3 weeks, with the turbinate mucosa of the experimental group becoming significantly thicker than in the control group. Immunostaining showed that IH increased the expression of TGFβ and N-cadherin and decreased E-cadherin expression in the turbinate mucosa. Quantitative PCR analysis demonstrated that IH enhanced the expression of not only the inflammatory markers Tnf-a, Il-1b, and Nos2 but also the EMT markers Tgf-b1, Col1a1, and Postn.

CONCLUSIONS

Collectively, these results suggest that IH induced turbinate hypertrophy via upregulation of gene expression related to inflammation and EMT in the nasal mucosa.

Protective effect of bergapten in acetic acid-induced colitis in rats

Bergapten (5-methoxysporalen) is a furanocoumarin extracted from several species of citrus and bergamot oil. Bergamot essential oil is used traditionally in the management of inflammatory conditions. Previous studies on bergapten have explored mainly its in vitro anti-inflammatory activities which include suppression of the expression and release of pro-inflammatory cytokines such as TNF-α and interleukins as well as prostaglandins. Bergapten enhances the clearance of neutrophils and macrophages from the site of inflammation and reduces oxidative stress by inhibition of reactive oxygen species (ROS). Bergapten was assessed for its anti-inflammatory properties in acetic acid-induced colitis. Animals were obtained and randomly placed in six (6) groups (n = 5) after acclimatization. Colitis was induced by rectal administration using 4% v/v acetic acid in Sprague Dawley rats after pre-treatment for 5 days. Bergapten was administered at doses of 3, 10, and 30 mg kg-1 p.o. while the control group received saline 5 mL kg-1 p.o. and the standard drug employed was sulphasalazine at a dose of 500 mg kg-1. Assessments made for colon-weight-to-length ratio, colonic injury, and mucosal mast cell degranulation. There were reduced colon-weight-to-length ratios in animals treated with bergapten which was significant (p < 0.5) for doses 10 and 30 mg kg-1 compared to the disease control group Both macroscopic and microscopic damage were reduced as well, with a lesser percentage of degranulated mast cells. Macroscopic damage was reduced for bergapten at doses 10 and 30 mg kg-1 significantly at p < 0.5 and p < 0.001, respectively. Similarly, microscopic damage was reduced at p < 0.01 and p < 0.001 respectively for bergapten 10 and 30 mg kg-1. The reduction of degranulation by bergapten was significant at p < 0.001. There was generally reduced damage at inflammatory sites as well as decreased infiltration of inflammatory cells. Overall, bergapten reduces inflammation in acetic acid-induced colitis.

Functional Infrared Thermal Imaging: A Contemporary Tool in Soft Tissue Screening

Soft tissue injury screening faces two main diagnostic challenges. One is the perceptual bias of the athlete in terms of referred pain and second injury assessment tools are not only in need of highly specialized personal but they are also financially demanding. Since ankle sprains is one of the leading soft tissue injuries, the current study was set to examine the suitability of functional infrared thermal imaging (fITI) in evaluating physiological alteration on the ankle as a result of exercise or injury. The current study consists of a case report of a patient with an ankle sprain and the behavior of temperature after a series of physiotherapy sessions. Moreover to strengthen the communication of the report, results from a healthy population sample were added to draw a deeper understanding on physiological temperature manifestations on soft tissue. Twenty participants underwent a 30-minute treadmill run with pictures of their ankles being taken during rest and after exercise. In addition the case of a patient is reported that has suffered an ankle sprain followed for a period of over a month. It was observed that the temperature of the ankles of participants that underwent physical exercise rose on average by 2.4 °C after taking into account both the medial and lateral sides of the both ankles. In addition the patient's left ankle appeared to be 2.5 °C above the temperature of the non-affected right ankle. This phenomenon of unilateral hyperthermia of the left injured side seems to start to dissipate by the 21st day following the injury, completely resolving by the 42nd day achieving bilateral isothermia in both ankles. Thermal imaging provides a reliable tool for the screening of soft tissue strain and injury. The current study further expands the literature on soft tissue screening with the use of thermal imaging, adding a quantifiable way for assessing the extend of tissue damage. The implemented method of analyses offers a suggested simple way not only in visualizing trauma but also physical strain. Nevertheless further investigations with a variety in the severity of ankle sprains need to be applied in order for thermal imaging to be used as a first line tool for the assessment and recovery of ankle sprains.

Intra-articular depletion of macrophages increases acute synovitis and alters macrophage polarity in the injured mouse knee

OBJECTIVE

Acute synovial inflammation following joint trauma is associated with posttraumatic arthritis. Synovial macrophages have been implicated in degenerative changes. In this study, we sought to elucidate the role of intra-articular macrophages in the acute inflammatory response to fracture in the mouse knee.

METHOD

A closed articular fracture was induced in two models of synovial macrophage depletion: genetically-modified MaFIA mice administered AP20187 to induce programmed macrophage apoptosis, and wild-type C57BL/6 mice administered clodronate liposomes, both via intra-articular injection. Synovial inflammation, bone morphology, and levels of F4/80+ macrophages, NOS2+ M1 macrophages, and CD206+ M2 macrophages were quantified 7 days after fracture using histology and micro-computed tomography.

RESULTS

Intra-articular macrophage depletion with joint injury did not reduce acute synovitis or the number of synovial macrophages 7 days after fracture in either macrophage-depleted MaFIA mice or in clodronate-treated C57BL/6 mice. In macrophage-depleted MaFIA mice, macrophage polarity shifted to a dominance of M1 macrophages and a reduction of M2 macrophages in the synovial stroma, indicating a shift in M1/M2 macrophage ratio in the joint following injury. Interestingly, MaFIA mice depleted 2 days prior to fracture demonstrated increased synovitis (P = 0.003), reduced bone mineral density (P = 0.0004), higher levels of M1 macrophages (P = 0.013), and lower levels of M2 macrophages (not statistically significant, P=0.084) compared to control-treated MaFIA mice.

CONCLUSION

Our findings indicate that macrophages play a critical immunomodulatory role in the acute inflammatory response surrounding joint injury and suggest that inhibition of macrophage function can have prominent effects on joint inflammation and bone homeostasis after joint trauma.

PLASMA RICH IN GROWTH FACTORS FOR PERSISTENT MACULAR HOLE: A PILOT STUDY

PURPOSE

Persistent macular hole (PMH) is a challenge for retina surgeons. There are limited surgical techniques described achieving PMH closure. For more than a decade, techniques with blood derivatives have been described without optimal outcomes. The aim of this article is to report the usefulness of the plasma rich in growth factors (PRGF) as a new way to improve PMH closure.

METHODS

This is an observational study. Two patients with PMH were chosen at the FOSCAL Internacional, Floridablanca, Colombia. For each patient, a complete ophthalmological examination before and after treatment was performed. It included best-corrected visual acuity and fundus examination. Features of swept-source optical coherence tomographic angiography (Topcon) at baseline and after treatment were included. Preoperative evaluation included the following: previous vitreoretinal surgery for macular hole, macular hole measurement and classification, and dissociated optic nerve fiber layer in en-face map, confirming a prior internal limiting membrane peeling. Plasma rich in growth factors-Endoret technology is characterized by moderate platelet concentration and absence of leukocytes, which requires calcium chloride for platelet activation. It is obtained from each patient's blood sample, submitted to a series of processes to acquire a three-dimensional fibrin scaffold, rich in hundreds of proteins, which seems to have therapeutic potential. This PRGF membrane is placed into the macular hole with forceps through a pars plana vitrectomy after complete air-fluid exchange. Supernatant was placed on the macula and left it for 2 minutes. It is then aspirated, and gas or silicone oil was left as a tamponade.

RESULTS

Follow-up period was of 12 months for each patient. Complete macular hole closure was achieved in both cases. Best-corrected visual acuity changed from 20/200 preoperatively to 20/100 postoperatively in Patient #1 and from 20/1,500 to 20/100 in Patient #2.

CONCLUSION

Plasma rich in growth factors has been primarily investigated for ocular surface diseases. This is a pilot study using this technology for PMH treatment. The use of PRGF may be an effective and safe surgical technique with satisfactory anatomical and functional results for PMH. Because of its own biomaterials and proteins, PRGF not only allows anatomical closure but also seems to stimulate tissue regeneration.

Reduction of paw edema and liver oxidative stress in carrageenan-induced acute inflammation by Lobaria pulmonaria and Parmelia caperata, lichen species, in mice

Paw edema volume reduction is a useful marker in determining the anti-inflammatory effect of drugs and plant extracts in carrageenan-induced acute inflammation. In this study, the anti-inflammatory effect of Lobaria pulmonaria (LP) and Parmelia caperata (PC), two lichen species, was examined in carrageenan-induced mouse paw edema test. Compared to the controls in carrageenan-induced inflammation (n = 5/group), our results showed that pretreatment by single oral doses with PC extract (50-500 mg/kg) gives better results than LP extract (50-500 mg/kg) in terms of anti-edematous activity, as after 4 h of carrageenan subplantar injection, paw edema formation was inhibited at 82-99% by PC while at 35-49% by LP. The higher anti-inflammatory effect of PC, at all doses, was also observed on the time-course of carrageenan-induced paw edema, displaying profile closely similar to that obtained with diclofenac (25 mg/kg), an anti-inflammatory drug reference (all p < 0.001). Both LP and PC, at all doses, significantly ameliorated liver catalase (CAT) activity (all p < 0.05). However, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity and glutathione (GSH) levels were found increased in liver of PC- compared to LP-carrageenan-injected mice. Our findings demonstrated on one hand higher preventive effects of PC compared to LP in a mouse carrageenan-induced inflammatory model and suggested, on the other hand, that anti-inflammatory effects elicited by the two lichens were closely associated with the amelioration in the endogenous antioxidant status of liver.

(Whole-Body) Electromyostimulation, Muscle Damage, and Immune System: A Mini Review

Exercise-induced muscular damage (EIMD) is a well-known phenomenon in exercise medicine that is closely related to the type and intensity of training, with especially eccentric training content providing various physiological irritations, including mechanical as well as metabolic. Besides the increase in markers of muscular damage, such as creatine kinase (CK) and myoglobin (Mb), several physiological shifts trigger a kind of stepwise repair chain reactions lasting over a time course from several hours to days. Subsequent inflammatory processes are closely related to muscular damage with decisive influence on physiological repair mechanisms, as indicated by an increased invasion of immune cells and typical patterns of pro- and anti-inflammatory cytokines. Previously, whole-body electromyostimulation (WB-EMS) showed significant, partly extreme distractions in markers of muscular damage lasting over several days. Because of the large area of stimulated muscle mass and a relatively high proportion of eccentric movements, initially too intense WB-EMS is predisposed to produce serious changes on several physiological levels due to its unfamiliar muscular strain. Therefore, it is the aim of this short review to focus on the possible immunological side effects of this aspiring training technology. As the number of original investigations in this field is rather small, we will include data from other studies about the relation of exercise-induced muscle damage and immune regulation.

Differing efficacies of autologous platelet-rich plasma treatment in reducing pain following rotator-cuff injury in a single patient

Rotator-cuff tears (RCTs) are typically associated with chronic pain. The most common treatment for reducing pain is the injection of cortisone into the injury site. An alternative and increasingly used technique is the injection of autologous platelet-rich plasma (PRP). A limitation of cortisone is its pain relief is short-lived, while PRP has the limitation of providing pain relief to only about 50% of patients, making its efficacy questioned, although when it is effective, its efficacy is longer than cortisone. Little is known about what accounts for these limitations. This paper presents results from a patient with RCTs causing excruciating pain who received an injection of PRP into that shoulder resulting in complete pain elimination that was ongoing at 2 years and 2 months. When 7-month severe posttrauma pain associated with the RCT developed in the contralateral shoulder, PRP prepared the same way and injected by the same person who performed the first injection provided no pain relief. However, a subsequent single cortisone injection resulted in complete pain elimination, which was ongoing at >15 months. These observations indicate that PRP can have inconsistent effects in reducing pain, not only between patients but also within the same patient. Further, although the pain relief induced by cortisone is normally not long-lasting, when given following a PRP injection, it can induce complete pain relief lasting >15 months. This paper discusses possible reasons for the variability in PRP efficacy on pain relief and addresses the possibility that when administered together, PRP and cortisone may act in a complementary manner, leading to significantly greater and longer-lasting pain relief.

Relationships between the inflammatory potential of the diet, aging and anthropometric measurements in a cross-sectional study in Pakistan

BACKGROUND

Little is known about associations between dietary inflammation, age and anthropometric measurements.

OBJECTIVE

In this regard, we examine how DII is related to age, anthropometrics [weight, Body mass index (BMI), waist to hip ratio (WHR)] and other parameters of nutrition (energy, protein, fats and cholesterol intake, Net Endogenous Acid Production (NEAP) and Phytochemical Index (PI)) in a cross-sectional study in Pakistan.

DESIGN

Only men (n = 651, age 54-95 years) participated in the study. Anthropometric data were collected using standard methods. DII was calculated from nutrients derived from 24-hr Dietary Recall questionnaires. NEAP and PI were calculated by established algorithms using information on nutrient intake.

RESULTS

The results show that with increasing age, there was a significant increase in the DII score (p < 0.05). Similarly significant positive correlations were found between DII score and weight, BMI, WHR and % BF (p, for all trends < 0.05). DII score significantly positively correlated with the dietary factors studied i.e. energy, protein, and fats (p, for all trends < 0.0001) but non-significantly with cholesterol (p > 0.05). Similarly, a significant positive correlation with NEAP (p < 0.0001) was found, but negative with PI (p < 0.0001).

CONCLUSION

In conclusion, the present study shows direct positive correlations between the DII, age and indices of obesity, and thus supports the hypothesis that diet may have a role in the development of obesity through inflammatory modulation mechanisms in elderly.

A Midterm Evaluation of Postoperative Platelet-Rich Plasma Injections on Arthroscopic Supraspinatus Repair: A Randomized Controlled Trial

BACKGROUND

Platelet-rich plasma (PRP) has been applied as an adjunct to rotator cuff repair to improve tendon-bone healing and potentially reduce the incidence of subsequent tendon retears.

PURPOSE

To investigate whether the midterm clinical and radiographic outcomes of arthroscopic supraspinatus repair are enhanced after repeated postoperative applications of PRP.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 60 patients (30 control; 30 PRP) were initially randomized to receive 2 ultrasound-guided injections of PRP to the tendon repair site at 7 and 14 days after double-row arthroscopic supraspinatus repair or not. A total of 55 patients (91.7%) underwent a clinical review and magnetic resonance imaging (MRI) at a mean of 3.5 years after surgery (range, 36-51 months). Patient-reported outcome measures (PROMs) included the Constant score, Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire, Oxford Shoulder Score (OSS), and visual analog scale (VAS) for pain. Global rating of change (GRC) scale and patient satisfaction scores were evaluated. Structural integrity of the surgical repair was assessed via MRI using the Sugaya classification system.

RESULTS

At the midterm review, there was no difference between the groups for any of the PROMs. No differences between the groups were demonstrated for the subjective and range of motion subscales of the Constant score, although a significantly higher Constant strength subscale score was observed in the PRP group (3.3 points; 95% CI, 1.0-5.7; P = .006). There was no evidence for any group differences in MRI scores or retear rates, with 66.7% of PRP patients and 64.3% of control patients rated as Sugaya grade 1. Two control patients had symptomatic retears (both full thickness) within the first 16 weeks after surgery compared with 2 PRP patients, who suffered symptomatic retears (both partial thickness) between 16 weeks and a mean 3.5-year follow-up.

CONCLUSION

Significant postoperative clinical improvements and high levels of patient satisfaction were observed in patients at the midterm review after supraspinatus repair. While pain-free, maximal abduction strength was greater in the midterm after PRP treatment, repeated applications of PRP delivered at 7 and 14 days after surgery provided no additional benefit to tendon integrity.

The use of platelet-rich plasma to treat chronic tendinopathies: A technical analysis

Platelet-rich plasma (PRP) is blood plasma with a high concentration of autologous platelets which constitute an immense reservoir of growth factors. The clinical use of PRP is widespread in various medical applications. Although highly popular with athletes, the use of PRP for the treatment of tendinopathies remains scientifically controversial, particularly due to the diversity of products that go by the name of "PRP." To optimize its use, it is important to look at the various stages of obtaining PRP. In this literature review, we take a closer look at eight parameters which may influence the quality of PRP: 1) anticoagulants used to preserve the best platelet function, 2) the speed of centrifugation used to extract the platelets, 3) the platelet concentrations obtained, 4) the impact of the concentration of red and while blood cells on PRP actions, 5) platelet activators encouraging platelet degranulation and, hence, the release of growth factors, and 6) the use or nonuse of local anesthetics when carrying out infiltration. In addition to these parameters, it may be interesting to analyze other variables such as 7) the use of ultrasound guidance during the injection with a view to determining the influence they have on potential recovery.

Antioxidant and anti-inflammatory activities of ethyl acetate extract of Gynura formosana (Kitam) leaves

Gynura formosana Kitam (family Compositae) has traditionally been used for the prevention of diabetes, cancer and inflammation in China. However, there are few reports of its anti-inflammatory effects. In the present study, after assessing the in vitro antioxidant activities of extracts from Gynura formosana Kitam leaves, the anti-inflammatory and antioxidant activities of ethyl acetate extract of Gynura formosana Kitam leaves (EAEG) were further investigated in rats using a cotton pellet-induced model of granuloma. EAEG significantly inhibited the formation of cotton pellet-induced granuloma in rats in a dose-dependent manner. Moreover, EAEG treatment significantly decreased the level of plasma C-reactive protein and suppressed the activities of plasma glutamate pyruvate transaminase and lactate dehydrogenase in model groups. Furthermore, EAEG increased the hepatic levels of anti-oxidative enzymes or antioxidants, including catalase, superoxide dismutase and reduced glutathione, and reduced the level of lipid peroxidation in the rat model of inflammation. In addition, EAEG decreased plasma levels of tumor necrosis factor-α and interleukin-1β in the rat model of inflammation. Therefore, our results indicated that EAEG had potent anti-inflammatory effects, which was achieved at least in part through activating antioxidant enzyme activities and suppressing the production of proinflammatory mediators by macrophages.

Efficacy of Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Meta-analysis of Randomized Controlled Trials

PURPOSE

To use meta-analysis techniques to evaluate the efficacy and safety of platelet-rich plasma (PRP) injections for the treatment knee of osteoarthritis (OA).

METHODS

We performed a systematic literature search in PubMed, Embase, Scopus, and the Cochrane database through April 2016 to identify Level I randomized controlled trials that evaluated the clinical efficacy of PRP versus control treatments for knee OA. The primary outcomes were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores. The primary outcomes were compared with their minimum clinically important differences (MCID)-defined as the smallest difference perceived as important by the average patient.

RESULTS

We included 10 randomized controlled trials with a total of 1069 patients. Our analysis showed that at 6 months postinjection, PRP and hyaluronic acid (HA) had similar effects with respect to pain relief (WOMAC pain score) and functional improvement (WOMAC function score, WOMAC total score, International Knee Documentation Committee score, Lequesne score). At 12 months postinjection, however, PRP was associated with significantly better pain relief (WOMAC pain score, mean difference -2.83, 95% confidence interval [CI] -4.26 to -1.39, P = .0001) and functional improvement (WOMAC function score, mean difference -12.53, 95% CI -14.58 to -10.47, P  < .00001; WOMAC total score, International Knee Documentation Committee score, Lequesne score, standardized mean difference 1.05, 95% CI 0.21-1.89, P = .01) than HA, and the effect sizes of WOMAC pain and function scores at 12 months exceeded the MCID (-0.79 for WOMAC pain and -2.85 for WOMAC function score). Compared with saline, PRP was more effective for pain relief (WOMAC pain score) and functional improvement (WOMAC function score) at 6 months and 12 months postinjection, and the effect sizes of WOMAC pain and function scores at 6 months and 12 months exceeded the MCID. We also found that PRP did not increase the risk of adverse events compared with HA and saline.

CONCLUSIONS

Current evidence indicates that, compared with HA and saline, intra-articular PRP injection may have more benefit in pain relief and functional improvement in patients with symptomatic knee OA at 1 year postinjection.

LEVEL OF EVIDENCE

Level I, meta-analysis of Level I studies.

Muscle damage and inflammation during recovery from exercise

Unaccustomed exercise consisting of eccentric (i.e., lengthening) muscle contractions often results in muscle damage characterized by ultrastructural alterations in muscle tissue, clinical signs, and symptoms (e.g., reduced muscle strength and range of motion, increased muscle soreness and swelling, efflux of myocellular proteins). The time course of recovery following exercise-induced muscle damage depends on the extent of initial muscle damage, which in turn is influenced by the intensity and duration of exercise, joint angle/muscle length, and muscle groups used during exercise. The effects of these factors on muscle strength, soreness, and swelling are well characterized. By contrast, much less is known about how they affect intramuscular inflammation and molecular aspects of muscle adaptation/remodeling. Although inflammation has historically been viewed as detrimental for recovery from exercise, it is now generally accepted that inflammatory responses, if tightly regulated, are integral to muscle repair and regeneration. Animal studies have revealed that various cell types, including neutrophils, macrophages, mast cells, eosinophils, CD8 and T-regulatory lymphocytes, fibro-adipogenic progenitors, and pericytes help to facilitate muscle tissue regeneration. However, more research is required to determine whether these cells respond to exercise-induced muscle damage. A large body of research has investigated the efficacy of physicotherapeutic, pharmacological, and nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage, with mixed results. More research is needed to examine if/how these treatments influence inflammation and muscle remodeling during recovery from exercise.

Two-staged application of PRP in arthroscopic rotator cuff repair: a matched-pair analysis

INTRODUCTION

Failure rates after arthroscopic rotator cuff repair remain high. Platelet-rich plasma has gained interest as a potential biological augmentation to enhance bone-tendon healing. The purpose of this study is to evaluate the clinical and structural outcomes of repeated PRP application on rotator cuff repair.

MATERIALS AND METHODS

Thirty-six patients underwent arthroscopic reconstruction, using knotless anchor double-row repair. Eighteen patients [10 female, 8 male; 61.2 (±9.2) years] received two applications of PRP-directly subsequent to the repair and 7 days postoperatively. Eighteen patients [11 male, 7 female; 61.4 (±6.5) years] who solely received the same technique of rotator cuff repair were matched for age. The subjective shoulder value, WORC, and the Constant-Murley score were used for clinical evaluation. MRI was performed for tendon integrity, and cuff appearances were graded according to the Sugaya classification.

RESULTS

We prospectively evaluated the PRP group with a minimum follow-up of 24 months. Clinical results did not show significantly differences in comparison to patients with isolated rotator cuff repair concerning CS (79 ± 13 vs. 77 ± 13; P = 0.6), SSV (90 ± 14 vs. 88 ± 16; P = 0.5) or WORC Score (90 ± 18 vs. 86 ± 20; P = 0.2). At the final follow-up, MRI showed retears in 11 % of the PRP and in 28 % of the control group (P = 0.4).

CONCLUSIONS

Knotless-anchor double-row repair shows good to excellent clinical results with an acceptable retear rate. Additional two-staged PRP application failed to significantly improve clinical parameters. Even though there was a trend for lower retear rates in the PRP group, it did not achieve statistical difference.

LEVEL OF EVIDENCE

Level III, Retrospective comparative study.

Treatment of Calcified Insertional Achilles Tendinopathy by the Posterior Midline Approach

The present study investigated the clinical outcomes of the posterior midline approach in the treatment of 34 patients with significantly calcified insertional Achilles tendinopathy. The posterior midline approach was applied for the surgical treatment of 34 patients with chronic significantly calcified insertional Achilles tendinopathy after failed conservative treatment. Gastrocnemius recession was performed simultaneously for patients with gastrocnemius contracture. The Fowler-Philip angle and parallel pitch lines were measured before surgery, and the visual analog scale, Tegner score, and Victorian Institute of Sport tendon study group score were recorded before and after surgery. The mean follow-up period was 45.2 ± 17.7 (range 24 to 84) months. After surgery, the visual analog scale score had decreased notably, and the Tegner score and Victorian Institute of Sport tendon study group score had increased significantly. The posterior midline approach can achieve satisfactory outcomes in the treatment of significantly calcified insertional Achilles tendinopathy, and gastrocnemius recession (Strayer procedure) should be performed for patients with gastrocnemius contracture to improve the surgical outcome.

Tendinopathy: Update on Pathophysiology

Synopsis Tendinopathy has become the accepted term to describe a spectrum of changes that occur in damaged and/or diseased tendons. Over the past 2 decades, there have been new insights into tendon pathophysiology of relevance to clinicians, including (1) better characterization of the overuse injury process and the resultant structural and functional disruption in chronically painful tendons, (2) improved understanding of the pathomechanics associated with chronic tendon injury, and (3) greater knowledge about the influence of lifestyle factors and drugs on tendon pathology. The implications of these new insights are discussed. J Orthop Sports Phys Ther 2015;45(11):833-841. Epub 21 Sep 2015. doi:10.2519/jospt.2015.5884.

Do postoperative platelet-rich plasma injections accelerate early tendon healing and functional recovery after arthroscopic supraspinatus repair? A randomized controlled trial

BACKGROUND

Tendon-bone healing after rotator cuff repair directly correlates with a successful outcome. Biological therapies that elevate local growth-factor concentrations may potentiate healing after surgery.

PURPOSE

To ascertain whether postoperative and repeated application of platelet-rich plasma (PRP) to the tendon repair site improves early tendon healing and enhances early functional recovery after double-row arthroscopic supraspinatus repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 60 patients underwent arthroscopic double-row supraspinatus tendon repair. After randomization, half the patients received 2 ultrasound-guided injections of PRP to the repair site at postoperative days 7 and 14. Early structural healing was assessed with MRI at 16 weeks, and cuff appearances were graded according to the Sugaya classification. Functional scores were recorded with the Oxford Shoulder Score; Quick Disability of the Arm, Shoulder and Hand; visual analog scale for pain; and Short Form-12 quality-of-life score both preoperatively and at postoperative weeks 6, 12, and 16; isokinetic strength and active range of motion were measured at 16 weeks.

RESULTS

PRP treatment did not improve early functional recovery, range of motion, or strength or influence pain scores at any time point after arthroscopic supraspinatus repair. There was no difference in structural integrity of the supraspinatus repair on MRI between the PRP group (0% full-thickness retear; 23% partial tear; 77% intact) and the control group (7% full-thickness retear; 23% partial tear; 70% intact) at 16 weeks postoperatively (P = .35).

CONCLUSION

After arthroscopic supraspinatus tendon repair, image-guided PRP treatment on 2 occasions does not improve early tendon-bone healing or functional recovery.

Leukocyte inclusion within a platelet rich plasma-derived fibrin scaffold stimulates a more pro-inflammatory environment and alters fibrin properties

One of the main differences among platelet-rich plasma (PRP) products is the inclusion of leukocytes that may affect the biological efficacy of these autologous preparations. The purpose of this study was to evaluate whether the addition of leukocytes modified the morphological, biomechanical and biological properties of PRP under normal and inflammatory conditions. The release of pro-inflammatory cytokines from plasma rich in growth factors (PRGF) and leukocyte-platelet rich plasma (L-PRP) scaffolds was determined by enzyme-linked immunosorbent assay (ELISA) and was significantly increased under an inflammatory condition when leukocytes were included in the PRP. Fibroblasts and osteoblasts treated with L-PRP, under an inflammatory situation, underwent a greater activation of NFĸB pathway, proliferated significantly less and secreted a higher concentration of pro-inflammatory cytokines. These cellular events were assessed through Western blot and fluorimetric and ELISA methods, respectively. Therefore, the inclusion of leukocytes induced significantly higher pro-inflammatory conditions.

Stereological quantification of immune-competent cells in baseline biopsy specimens from achilles tendons: results from patients with chronic tendinopathy followed for more than 4 years

BACKGROUND

Limited data exist on the presence and function of immune-competent cells in chronic tendinopathic tendons and their potential role in inflammation and tissue healing as well as in predicting long-term outcome.

PURPOSE

To quantify subtypes of immune-competent cells in biopsy specimens from nonruptured chronic tendinopathic Achilles tendons and healthy control tendons. In addition, to examine whether findings in baseline cell biopsy specimens can predict the long-term presence of Achilles tendon symptoms.

STUDY DESIGN

Cross-sectional and case-control study; Level of evidence, 3.

METHODS

Fifty patients with nonruptured chronic Achilles tendinopathy and 15 healthy participants were included. At time of inclusion, an ultrasound examination was performed immediately before an ultrasound-guided Achilles tendon biopsy specimen was obtained. Tissue samples were evaluated immunohistochemically by quantifying the presence of macrophages (CD68-PGM1(+), CD68-KP1(+)), hemosiderophages (Perls blue), T lymphocytes (CD2(+), CD3(+), CD4(+), CD7(+), CD8(+)), B lymphocytes (CD20(+)), natural killer cells (CD56(+)), mast cells (NaSDCl(+)), Schwann cells (S100(+)), and endothelial cells (CD34(+)) using a stereological technique. A follow-up examination was conducted more than 4 years (range, 4-9 years) after the biopsy procedure to evaluate the long-term presence of Achilles tendon symptoms.

RESULTS

Macrophages, T lymphocytes, mast cells, and natural killer cells were observed in the majority (range, 52%-96%) of biopsy specimens from nonruptured chronic tendinopathic Achilles tendons. CD68-KP1(+) macrophages (0.29% vs 0; P = .005) and CD34(+) endothelial cells (3% vs 0.97%; P = .04) were significantly more numerous in tendinopathic tendons compared with healthy tendons. The presence of iron(+) hemosiderophages was more frequently observed in biopsy specimens obtained from the group who was asymptomatic at follow-up compared with the symptomatic group (42% vs 5%; P = .02).

CONCLUSION

This study provides evidence for the presence of immune-competent cells in the majority of biopsy specimens from nonruptured chronic tendinopathic Achilles tendons. Macrophages and endothelial cells were significantly more numerous in tendinopathic tendons than in healthy tendons. The presence of iron(+) hemosiderophages in baseline biopsy specimens was associated with a good prognosis.

CLINICAL RELEVANCE

New insight into the role of immune-competent cells in chronic Achilles tendinopathy.

Anti-inflammatory and antioxidant activities of the methanol extract of Gynura segetum leaf

Gynura segetum, family Compositae, is a cultivated species and can be found growing in the tropical regions of Indonesia and Malaysia. The plant is known for its use for the treatment of cancer, inflammation, diabetes, hypertension and skin afflictions. In the current study, in vivo anti-inflammatory effect of the methanol extract G. segetum leaf and its antioxidant effect in vitro have been investigated for the first time. The in vitro antioxidant activities of the methanol extract were measured using common methods including total phenolic content; total flavonoid content; scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene bleaching assays. The in vivo anti-inflammatory activities were tested using the cotton pellet implanted animal model. The measurement of pro-inflammatory cytokine (TNF-α and IL-1) levels in the blood samples of the rats was carried out by using ELISA kits. The inhibitory activity on cyclooxygenase (COX) enzyme of methanol extract was also evaluated. The methanol extract exhibited good antioxidant activity which is associated with their total phenolic and flavonoid contents. Methanol extract strongly inhibited the granuloma tissue formation in rats and the anti-inflammatory potential was mediated through the inhibition of pro-inflammatory cytokines and COX-2 enzyme activities. Taken together, the present study suggests that G. segetum's leaf is a natural source of antioxidants and has potential therapeutic benefits against chronic inflammation.

The resolution of inflammation: a mathematical model of neutrophil and macrophage interactions

There is growing interest in inflammation due to its involvement in many diverse medical conditions, including Alzheimer's disease, cancer, arthritis and asthma. The traditional view that resolution of inflammation is a passive process is now being superceded by an alternative hypothesis whereby its resolution is an active, anti-inflammatory process that can be manipulated therapeutically. This shift in mindset has stimulated a resurgence of interest in the biological mechanisms by which inflammation resolves. The anti-inflammatory processes central to the resolution of inflammation revolve around macrophages and are closely related to pro-inflammatory processes mediated by neutrophils and their ability to damage healthy tissue. We develop a spatially averaged model of inflammation centring on its resolution, accounting for populations of neutrophils and macrophages and incorporating both pro- and anti-inflammatory processes. Our ordinary differential equation model exhibits two outcomes that we relate to healthy and unhealthy states. We use bifurcation analysis to investigate how variation in the system parameters affects its outcome. We find that therapeutic manipulation of the rate of macrophage phagocytosis can aid in resolving inflammation but success is critically dependent on the rate of neutrophil apoptosis. Indeed our model predicts that an effective treatment protocol would take a dual approach, targeting macrophage phagocytosis alongside neutrophil apoptosis.

Morphogen and proinflammatory cytokine release kinetics from PRGF-Endoret fibrin scaffolds: evaluation of the effect of leukocyte inclusion

The potential influence of leukocyte incorporation in the kinetic release of growth factors from platelet-rich plasma (PRP) may explain the conflicting efficiency of leukocyte platelet-rich plasma (L-PRP) scaffolds in tissue regeneration. To assess this hypothesis, leukocyte-free (PRGF-Endoret) and L-PRP fibrin scaffolds were prepared, and both morphogen and proinflammatory cytokine release kinetics were analyzed. Clots were incubated with culture medium to monitor protein release over 8 days. Furthermore, the different fibrin scaffolds were morphologically characterized. Results show that leukocyte-free fibrin matrices were homogenous while leukocyte-containing ones were heterogeneous, loose and cellular. Leukocyte incorporation produced a significant increase in the contents of proinflammatory cytokines interleukin (IL)-1β and IL-16 but not in the platelet-derived growth factors release (<1.5-fold). Surprisingly, the availability of vascular endothelial growth factor suffered an important decrease after 3 days of incubation in the case of L-PRP matrices. While the release of proinflammatory cytokines was almost absent or very low from PRGF-Endoret, the inclusion of leukocytes induced a major increase in these cytokines, which was characterized by the presence of a latent period. The PRGF-Endoret matrices were stable during the 8 days of incubation. The inclusion of leukocytes alters the growth factors release profile and also increased the dose of proinflammatory cytokines.

Relevant aspects of centrifugation step in the preparation of platelet-rich plasma

Introduction. Platelet-Rich Plasma (PRP) is rich in growth factors, playing important role in tissue healing. The wide variation of reported protocols for preparation of PRP leads to variable compositions, which induce different biological responses and prevent results comparison. This study aims to highlight relevant aspects of the centrifugation step to obtain reproducible results and overall quality. Material and Methods. Samples of blood were collected from 20 healthy donors that have signed free informed consent. Two centrifugation steps (spins) were analyzed for the influence of centrifugal acceleration, time, processed volume, and platelet gradient. The Pure Platelet-Rich Plasma (P-PRP) was characterized as platelet concentration, integrity, and viability (sP-selectin measurement). Results. Lower centrifugal accelerations favour platelet separation. The processing of 3.5 mL of blood at 100 ×g for 10 min (1st spin), 400 ×g for 10 min (2nd spin), withdrawing 2/3 of remnant plasma, promoted high platelet recovery (70–80%) and concentration (5x) maintaining platelet integrity and viability. The recovery of platelets was reduced for a larger WB volume (8.5 mL) processed. Conclusion. Centrifugal acceleration, time, WB processed volume, and minimization of the platelet gradient before sampling are relevant aspects to ensure reproducible compositions within the autologous nature of PRP.

Application of Platelet-Rich Plasma to Disorders of the Knee Joint

IMPORTANCE

The promising therapeutic potential and regenerative properties of platelet-rich plasma (PRP) have rapidly led to its widespread clinical use in musculoskeletal injury and disease. Although the basic scientific rationale surrounding PRP products is compelling, the clinical application has outpaced the research.

OBJECTIVE

The purpose of this article is to examine the current concepts around the basic science of PRP application, different preparation systems, and clinical application of PRP in disorders in the knee.

EVIDENCE ACQUISITION

A systematic search of PubMed for studies that evaluated the basic science, preparation and clinical application of platelet concentrates was performed. The search used terms, including platelet-rich plasma or PRP preparation, activation, use in the knee, cartilage, ligament, and meniscus. Studies found in the initial search and related studies were reviewed.

RESULTS

A comprehensive review of the literature supports the potential use of PRP both nonoperatively and intraoperatively, but highlights the absence of large clinical studies and the lack of standardization between method, product, and clinical efficacy. Conclusions and Relevance. In addition to the call for more randomized, controlled clinical studies to assess the clinical effect of PRP, at this point, it is necessary to investigate PRP product composition and eventually have the ability to tailor the therapeutic product for specific indications.

A biological therapy to osteoarthritis treatment using platelet-rich plasma

INTRODUCTION

Osteoarthritis (OA) is a degenerative disease affecting the synovial joint. It is caused by cells exposure to non-physiological stimuli, either mechanical or biochemical, and the loss of bone-cartilage homeostasis. Some of these changes, however, may be reversed by the use of single or combined growth factors, suggesting that the treatment of OA could be addressed using a pool of growth factors.

AREAS COVERED

This review addresses current molecular and biological knowledge and implicates the recapitulation of some developmental processes during endochondral ossification in OA aetiology and pathogenesis. Platelets act as carriers of endogenous morphogens that may modulate cell fate and therefore affect joint tissues structure and function. We shed light on the platelet-rich plasma effects on biological level that might drive the osteoarthritic joint's improvement both in structure and function.

EXPERT OPINION

We present the therapeutic potential of plasma rich in growth factors (PRGF-Endoret), an endogenous biological therapy that might modulate the gene expression of cells such as chondrocytes, synoviocytes, macrophages, and mesenchymal stem cells, and thereby influence an anabolic microenvironment of synovial joint which is conducive to maintaining the homeostatic state of the joint's tissues, and hence reduce pain and improve the joint motion.

Comparison between hyaluronic acid and platelet-rich plasma, intra-articular infiltration in the treatment of gonarthrosis

BACKGROUND

Arthrosis is particularly prevalent in the knee. Infiltration treatment for gonarthrosis is among the most widely used techniques in orthopaedic practice.

PURPOSE

To compare the clinical response of hyaluronic acid (HA) and platelet-rich plasma (PRP) treatment in 2 groups of patients affected by gonarthrosis.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 120 patients affected by clinically and radiographically documented gonarthrosis were included in this study. The gonarthrosis was graded using the Kellgren-Lawrence radiographic classification scale. The 120 patients were randomized into 2 study groups in a 1:1 ratio: 60 patients received 4 intra-articular injections of PRP (specifically, autologous conditioned plasma [ACP], 5.5 mL), and 60 patients received 4 intra-articular injections of HA (20 mg/2 mL). An unblinded physician performed infiltration once a week for 4 weeks into the knee affected by clinically relevant gonarthrosis (in both groups). All patients were evaluated with the Western Ontario and McMaster (WOMAC) score before the infiltration and at 4, 12, and 24 weeks after the first injection.

RESULTS

Treatment with a local injection of ACP had a significant effect shortly after the final infiltration and a continuously improving sustained effect up to 24 weeks (WOMAC score, 65.1 and 36.5 in the HA and ACP groups, respectively; P < .001), where the clinical outcomes were better compared with the results with HA. In the HA group, the worst results were obtained for grade III gonarthrosis, whereas the clinical results obtained in the ACP group did not show any statistically significant difference in terms of the grade of gonarthrosis. The mean WOMAC scores for grade III gonarthrosis were 74.85 in the HA group and 41.20 in the ACP group (P < .001).

CONCLUSION

Treatment with ACP showed a significantly better clinical outcome than did treatment with HA, with sustained lower WOMAC scores. Treatment with HA did not seem to be effective in the patients with grade III gonarthrosis.

Platelet-rich plasma (PRP): an adjuvant to hasten hamstring muscle recovery. A randomized controlled trial protocol (ISCRTN66528592)

BACKGROUND

Muscle injuries are one of the commonest injuries affecting athletes. It often leads to significant pain and disability causing loss of training and competition time. With current treatment, the duration to return-to-play ranges form six weeks to never, depending on injury severity. Recent researches have suggested that autologous platelet-rich plasma (PRP) injection into the injured site may hasten soft tissues healing. To-date, there has been no randomised clinical trials to evaluate the effects of PRP on muscle healing. The aim of this study is to examine the effects of autologous PRP on duration to return-to-play after muscle injury.

METHODS AND DESIGN

A randomised, single blind controlled trial will be conducted. Twenty-eight patients aged 18 years and above with a recent grade-2 hamstring injury will be invited to take part. Participants will be randomised to receive either autologous PRP injection with rehabilitation programme, or rehabilitation programme only. Participants will be followed up at day three of study and then weekly for 16 weeks. At each follow up visit, participants will be assessed on readiness to return-to-play using a set of criteria. The primary end-point is when participants have fulfilled the return-to-play criteria or end of 16 weeks.The main outcome measure of this study is the duration to return-to-play after injury.

CONCLUSION

This study protocol proposes a rigorous and potential significant evaluation of PRP use for grade-2 hamstring injury. If proven effective such findings could be of great benefit for patients with similar injuries.

TRIAL REGISTRATION

Current Controlled Trials ISCRTN66528592.

VGluT2 and NMDAR1 expression in cells in the inflammatory infiltrates in experimentally induced myositis: evidence of local glutamate signaling suggests autocrine/paracrine effects in an overuse injury model

It is not known whether a glutamate signaling system is involved in muscle inflammation (myositis). In the present study, we examined this question in the soleus muscle in a laboratory model of myositis resulting from repetitive overuse induced by electrical stimulation and injection of pro-inflammatory substances. Sections of rabbit soleus muscle with an induced myositis, i.e., exhibiting infiltration of inflammatory cells, were examined immunohistochemically using antibodies against vesicular glutamate transporter VGluT2 and the glutamate receptor NMDAR1. In situ hybridization for demonstration of VGluT2 mRNA was also performed. Specific reactions for both VGluT2 and NMDAR1 could be observed immunohistochemically in the same cells. In situ hybridization demonstrated the occurrence of VGluT2 mRNA in the cells. Double staining showed that the VGluT2 reactions were detectable in cells marked with T cell/neutrophil marker and in cells expressing eosinophil peroxidase. These data suggest the occurrence of previously unknown glutamate-mediated autocrine/paracrine effects within the inflammatory infiltrates during the development of muscle inflammation.

Platelet activation: ultrastructure and morphometry in platelet-rich plasma of horses

This study was conducted to investigate the activation ability of the platelet-rich plasma (PRP) by pharmacological agents, as well as to verify the need or not of this activation for therapeutic use. The PRP was obtained from four healthy crossbred geldings aged 13 to 16 years (15±1years), and was processed for observation and quantification of the platelet morphology by using the transmission electron microscopy. All PRP samples were activated with 10% calcium chloride (CaCl2) solution, pure bovine thrombin or associated with CaCl2. The control (pure PRP) was not pharmacologically activated. In the pure PRP samples, 49% of the platelets were classified as state of activation uncertain, 41% as resting, 9% as fully activated and 1% as irreversibly damaged. Treatment with 10% CaCl2 provided a distribution of 54% platelets in state of activation uncertain, 24% as fully activated, 20% as resting, and 2% as irreversibly damaged. The platelet morphology of the bovine thrombin treated samples did not fit into classification adopted, as showing irregular shape with emission of large filamentous pseudopods, appearance of ruptured and whole granules in the remaining cytoplasm and extracellular environment. There was effect of the treatment on the platelet morphology (P=0.03). The 10% CaCl2 is an adequate platelet-activating agent. However, in cases the use of PRP under its liquid form is necessary, the use of pure PRP is recommended, since besides presenting an adequate percentage of fully activated platelets it also has significant amount of the resting type, which can be activated by substances found in the injured tissue.