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Papers by Isabel Andia

Therapeutic Advances in Musculoskeletal Disease, 2021

Sports injuries and secondary joint problems, mainly of the knee, are common, especially in sport... more Sports injuries and secondary joint problems, mainly of the knee, are common, especially in sports associated with high impact activities and/or torsional loading. The consequences can be career ending in elite athletes and reduce exercise activities in recreational people. Various cell products can be injected intra-articularly. First, fresh cellular mixtures can be prepared and injected in the same day, such as stromal vascular fraction of adipose tissue (SVF) and bone marrow concentrates (BMCs). Second, autologous mesenchymal stromal cells (MSCs) can be isolated from BMCs or SVF and, after several weeks of laboratory expansion, several millions of MSCs can be obtained for intra-articular injection. Finally, allogeneic MSCs from the bone marrow, adipose tissue or perinatal tissues of selected donors constitute an 'off-the-shelf' experimental treatment for injection delivery in patients with osteoarthritis of the knee. The perceived efficacy of all these products is based on the hypothesis of a paracrine mechanism of action: when living cells are delivered within the joint, they establish a molecular cross-talk with immune cells and local cell phenotypes, thereby modulating inflammation with subsequent modifications in the catabolic/degenerative milieu. Current clinical research examines whether injection delivery of MSCs translates into actual clinical benefits. Overall, clinical studies lack the quality needed to answer major research questions, including clinical and structural efficacy, optimal cell dose, and number of injections and specific protocol for cell delivery. Poor experimental designs are exacerbated by the diversity of patient phenotypes that hinder comparisons between treatments. Further understanding of disease pathology is paramount to develop potent function assays and understand whether the host tissue, the cell product or both should be primed before MSCs are injected intra-articularly.

Expert Opinion on Biological Therapy, Sep 27, 2019

Introduction: The heterogeneous pool of cells found in the stromal vascular fraction of adipose t... more Introduction: The heterogeneous pool of cells found in the stromal vascular fraction of adipose tissue (SVF) and the purified mesenchymal stromal/stem cells (ASCs) A c c e p t e d M a n u s c r i p t isolated from this pool have increasingly been used as therapeutic tools in regenerative medicine. Areas covered: As SVF and ASCs are different, and should be used in different manners according to various clinical and biological indications, we reviewed the current literature, and focused on the clinical use of SVF to appraise the main medical fields for development. Both enzymatic digestion and mechanical disruption have been used to obtain SVF for non-homologous use at the point of care. The safety and/or benefits of SVF have been examined in 71 clinical studies in various contexts, mainly musculoskeletal conditions, wound healing, urogenital, and cardiovascular and respiratory diseases. The use of SVF as a therapy remains experimental, with few clinical trials. Expert Opinion: SVF provides a cellular and molecular microenvironment for regulation of ASC' activities under different clinical conditions. SVF may enhance angiogenesis and neovascularization in wound healing, urogenital and cardiovascular diseases. In joint conditions, therapeutic benefits may rely on paracrine immunemodulatory and anti-inflammatory mechanisms. Novel point of care methods are emerging to refine SVF in ways that meet the regulatory requirements for minimal manipulation.

Techniques in Shoulder and Elbow Surgery, Sep 1, 2017

Tendinopathy in upper limb tendons, driven by overuse or understimulation, is very frequent in th... more Tendinopathy in upper limb tendons, driven by overuse or understimulation, is very frequent in the general population. Because of the absence of effective treatments, biological approaches are currently being investigated. Platelet-rich plasma (PRP) is injected locally for the conservative management of epicondylar and rotator cuff tendinopathy, or as a biological enhancer in arthroscopic repair of rotator cuff tears. In epicondylar tendinopathy, we have identified 15 randomized clinical studies comparing the efficacy of PRP with other injectable treatments. PRP has been compared with corticosteroids in 8 randomized trials, showing better results in long-term clinical outcomes; PRP was compared with peripheral blood in 3 studies, showing similar outcomes but fewer adverse effects; 2 studies showed superiority of PRP versus anesthetics using a peppering technique. In 1 study, PRP did not show any clinical efficacy when compared with dry needling, and no efficacy in 2 studies compared with saline injections. Four randomized controlled studies have examined PRP injections in chronic shoulder tendinopathy, but the evidence is inconclusive. PRP as an enhancer of arthroscopic management is questionable but data are evolving as more subgroup analyses become available. PRP therapies have only partially fulfilled therapeutic expectative, and new approaches are necessary.

American Journal of Sports Medicine, May 30, 2014

Background: Intra-articular (IA) treatment with platelet-rich plasma (PRP) for osteoarthritis (OA... more Background: Intra-articular (IA) treatment with platelet-rich plasma (PRP) for osteoarthritis (OA) results in improved patient-reported pain and function scores. Purpose: To measure the effects of PRP and high molecular weight hyaluronan (HA) on the expression of anabolic and catabolic genes and on the secretion of nociceptive and inflammatory mediators from OA cartilage and synoviocytes. Study Design: Controlled laboratory study. Methods: Synovium and cartilage harvested from patients undergoing total knee arthroplasty were co-cultured with media of PRP or HA. Tumor necrosis factor–α (TNF-α), interleukin-6 (IL-6), and IL-1β were measured in the media by enzyme-linked immunosorbent assay. Hyaluronan synthase–2 ( HAS-2), matrix metalloproteinase–1 ( MMP-1), MMP-13, and TNF-α genes were measured in synoviocytes by reverse transcription polymerase chain reaction (RT-PCR). Collagen type I α1 ( COL1A1), COL2A1, aggrecan ( ACAN), and MMP-13 gene expression were measured in cartilage by quantitative RT-PCR. Results: Media TNF-α concentration was decreased in PRP and HA compared with control cultures (PRP = 6.94 pg/mL, HA = 6.39 pg/mL, control = 9.70 pg/mL; P ≤ .05). Media IL-6 concentration was decreased in HA compared with PRP and control (HA = 5027 pg/mL, PRP = 5899 pg/mL, control = 5613 pg/mL; P ≤ .05). Media IL-1β was below detectable concentrations (<0.1 pg/mL) in all samples. Synoviocyte MMP-13 expression was decreased in PRP compared with HA and control (PRP = 10.1, HA = 12.8, control = 13.5; P ≤ .05). Synoviocyte HAS-2 expression was increased in PRP compared with HA and control (PRP = 12.1, HA = 9.8, control = 8.7; P ≤ .05). Cartilage ACAN expression was increased in PRP compared with HA, but neither was different from control (PRP = 8.8, HA = 7.7, control = 7.6; P ≤ .05); COL1A1 expression was increased in HA compared with PRP, but neither was different from control (PRP = 14.9, HA = 13.5, control = 12.9; P ≤ .05). Neither platelet nor leukocyte concentration had a significant effect on outcome measurements (gene or protein expression data) in cartilage or synoviocytes ( P > .05). Conclusion: Both PRP and HA treatments of OA joint tissues result in decreased catabolism, but PRP treatment also resulted in a significant reduction of MMP-13, an increase in HAS-2 expression in synoviocytes, and an increase in cartilage synthetic activity compared with HA. These results indicate that PRP acts to stimulate endogenous HA production and decrease cartilage catabolism. Platelet-rich plasma showed similar effects as HA in the suppression of inflammatory mediator concentration and expression of their genes in synoviocytes and cartilage. Clinical Relevance: The antinociceptive and anti-inflammatory activities of PRP support its use in OA joints to reduce pain and modulate the disease process. This study supports further clinical investigations of IA PRP for the treatment of OA.

Journal of Orthopaedics and Traumatology, Aug 20, 2018

Very often, treatment for many common musculoskeletal conditions is only palliative, or involves ... more Very often, treatment for many common musculoskeletal conditions is only palliative, or involves surgery with major shortcomings. Biological interventions-in particular, platelet-rich plasma (PRP) therapies-may well provide more effective treatments, but their actual efficacy is under scrutiny. PRP is biologically unique to each individual depending on endogenous and exogenous factors, including, but not limited to, demographic factors (i.e. age), immune status (i.e. microbiota), metabolic diseases and concomitant medications. All these potential modifiers of the ultimate effects of PRP have been poorly explored, and their relationship with efficacy has not been established.

Operative Techniques in Orthopaedics, Mar 1, 2012

Knowledge of the basic biological mechanisms involved in tissue response to injury should inform ... more Knowledge of the basic biological mechanisms involved in tissue response to injury should inform management of healing. Approaches to influence healing may need to integrate multiple cell types and large signaling networks that are necessary for the dynamic communication between cells. Platelet-rich plasma (PRP) therapies deliver a myriad of growth factors and cytokines to the injured tissues. Evolution of our understanding of platelet biology and reinterpretation of some of their more traditional roles in hemostasis and tissue repair have revealed much about the complexity of PRP therapies and provide new insights on PRP therapies' successes and failures. However, many potential molecular mechanisms acting simultaneously in tissue repair present a challenge to the identification of critical mechanisms behind PRP therapies. A vast array of barriers, ranging from deficits in basic research to clinical differences in formulations and administration procedures, undermine current efforts to set effective PRP protocols to manage healing. Identifying which molecular mechanisms are more or less important during the course of healing and clarifying the molecular basis for differences in the healing response across patients will continue to be the priority to tailor PRP therapies for particular sports injuries.

Regenerative Medicine, Sep 1, 2018

The positive extensive clinical experience with platelet-rich plasma (PRP) in different medical a... more The positive extensive clinical experience with platelet-rich plasma (PRP) in different medical areas has prompted researchers to explore clinical opportunities for optimized PRP therapies. PRP is safe but we have to make it more effective. The growing diversity of formulations and presentations enrich the field of PRP research and offer hope to refine clinical indications. Moving toward targeting the right disease phenotypes with the right PRP formulation or combination product (PRP + cell products) can offer opportunities to change treatment options in osteoarthritis and nonhealing wounds. Both are active areas of research that could offer opportunities, although cost efficacy is still an open question. Our position is to believe that these serious disease areas are likely to benefit from PRP therapies.

PubMed, 2014

Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PR... more Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) - are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics.

Clinical Orthopaedics and Related Research, May 1, 2015

Background Platelet-rich plasma therapies for tendinopathy appear to provide moderate pain reduct... more Background Platelet-rich plasma therapies for tendinopathy appear to provide moderate pain reduction. However, the biological mechanisms behind the observed clinical effects remain poorly characterized. Questions/purposes The purpose of this study was to explore whether platelet-rich plasma modifies the inflammatory/angiogenic status of already inflamed tenocytes by examining (1) gene expression; (2) modulation of chemokine and interleukin secretion; and (3) differences between healthy and tendinopathic tenocytes. Methods Cells from both healthy and tendinopathic tendons were exposed to interleukin (IL)-1ß and after treated with platelet-rich plasma. Modifications in the expression of selected genes were assessed by real-time reverse transcription-polymerase chain reaction and changes in secretion of angiogenic/inflammatory molecules by enzyme-linked immunosorbent assay. Platelet-rich plasmainduced changes in tendinopathic cells were compared with normal after normalizing platelet-rich plasma data against IL-1ß status in each specific sample. Results In IL-1ß-exposed cells, platelet-rich plasma downregulates expression of IL-6/CXCL-6 (mean, 0.015; 95% confidence interval [CI], 0.005-0.025; p = 0.026), IL-6R (mean, 0.61; 95% CI, 0.27-0.95; p = 0.029), and IL-8/CXCL-8 (mean, 0.02; 95% CI, 0.007-0.023; p = 0.026). Secretion of IL-6/CXCL6, 0.35 (95% CI, 0.3-0.4; p = 0.002), IL-8/CXCL8, 0.55 (95% CI, 0.5-0.7; p = 0.01), and monocyte chemoattractant protein-1/CCL2, 0.40 (95% CI, 0.2-0.6; p = 0.001) was reduced by platelet-rich plasma, whereas vascular endothelial growth factor increased by twofold, (95% CI, 1.7-2.3; p \ 0.001). RANTES/CCL5 increased by10-fold (95% CI, 4-17) and hepatocyte growth factor by 21-fold (95% CI, 0.2-42) in tendinopathic and by 2.3-fold (95% CI, 2-3) and threefold (95% CI, 1-5) in normal cells (p = 0.005 for both). Conclusions Platelet-rich plasma induces an immunomodulatory and proangiogenic phenotype consistent with healing mechanisms with few differences between tendinopathic and normal cells. Clinical Relevance Platelet-rich plasma injections in pathological and nearby tissue might help to recover tendon homeostasis. The Department of Industry from the Basque Government provided financial support, SAIO2012-PE12BF007. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.

Expert Opinion on Biological Therapy, Dec 15, 2011

At the beginning of the new millennium, there was a breakthrough in platelet-rich plasma (PRP) th... more At the beginning of the new millennium, there was a breakthrough in platelet-rich plasma (PRP) therapy for tissue repair. The mechanisms governing the effects of this therapy in joint pathology remain largely unexplored. This review is primarily based on PubMed and Web of Knowledge searches with the terms osteoarthritis in combination with PRP, treatment, cartilage, synovium, platelets, inflammation and/or angiogenesis. This search was completed by a manual search for relevant studies. We mainly include papers from the last 5 years. The concept of dynamic reciprocity is used to shape understanding of the spatial relationship between cells and their microenvironments as well as between tissues within the joint. We describe the processes of joint injury and pathology relevant to the mechanism of action of PRP, and elaborate insights into how PRP components may influence inflammation, angiogenesis, cell death and cartilage chondroprotection. PRP therapies are more complicated than previously acknowledged, and an understanding of the fundamental processes and pivotal molecules involved will hopefully be elucidated soon. This challenge is to provide a comprehensive description of the relationship between PRP components, healing mechanisms and clinical outcomes. Although PRP therapies in clinical trials await assessment, they have shed light on new avenues of management because of their effects on repair functions.

Expert Opinion on Biological Therapy, Aug 18, 2010

The therapeutic use of platelet-rich plasma (PRP) is an autologous biotechnology that relies on t... more The therapeutic use of platelet-rich plasma (PRP) is an autologous biotechnology that relies on the local delivery of a wide range of growth factors and cytokines with the aim of enhancing tissue healing. Understanding both tendon healing and PRP therapies is an area of research that is critically important in developing optimal formulations and protocols to achieve the intended therapeutic effects. We summarise recent information on the mechanisms inherent to the earliest response to tendon injury. We then describe the positive effect of PRP therapies on tendon healing. Research on tendinopathy has produced several biological hypotheses based on histopathological, biochemical and clinical findings showing that cell apoptosis, angiofibroblastic features or abnormal biochemical adaptations underlie the condition. The article provides insights into early healing mechanisms and the influence of PRP therapies on inflammation, cell migration, angiogenesis and the proliferation and synthesis of extracellular matrix. The knowledge gained helps to better understand and optimize tendon therapies. The use of endogenous therapies has a positive effect on experimental tendon healing. However, several obstacles need to be addressed to optimise medical practice in this field.

Osteoarthritis (OA) is a common disease involving joint damage, an inadequate healing response an... more Osteoarthritis (OA) is a common disease involving joint damage, an inadequate healing response and progressive deterioration of the joint architecture. Autologous blood-derived products such as platelet- rich plasma (PRP) are key sources of molecules involved in tissue repair and regeneration. In pathological conditions such as OA, these products can deliver a collection of bioactive molecules that have important roles in fundamental processes, including inflammation, angiogenesis, cell migration and metabolism. PRP has anti-inflammatory properties through its effects on the canonical nuclear factor κ B signalling pathway in multiple cell types including synoviocytes, macrophages and chondrocytes. PRP contains thousands of different molecules; cells within the joint add to this milieu by secreting additional biologically active molecules in response to PRP. The net results of PRP therapy are varied and can include angiogenesis, the production of local conditions that favour anabolism in the articular cartilage, or the recruitment of repair cells. However, the molecules found in PRP that contribute to angiogenesis and the protection of joint integrity need further clarification. Understanding PRP in molecular terms could help us to exploit its therapeutic potential, and aid the development of novel treatments and tissue-engineering approaches, for the different stages of joint degeneration.

Therapeutic Advances in Musculoskeletal Disease, 2021

Intra-articular injections of platelet-rich plasma (PRP) and other novel bloodderived products de... more Intra-articular injections of platelet-rich plasma (PRP) and other novel bloodderived products developed specifically for osteoarthritis (OA) can provide pain relief and potential benefits in disease progression. Meta-analyses show the clinical superiority of PRP compared with other intra-articular injections, but results are modest and the effect sizes are small. PRP injections in knee OA are performed indiscriminately, but the clinical response varies enormously between patients because of an array of mixed OA phenotypes. Subgroup analyses are scarce; some studies stratify patients according to radiographic severity and found better results in early OA, without consensus for more advanced stages of the condition. Parallel identification of soluble and imaging biomarkers is essential to personalise and leverage PRP therapies. The inflammatory phenotype is most interesting from the PRP perspective because PRPs modulate inflammation by releasing a large pool of chemokines and cytokines, which interact with synovial fibroblasts and macrophages; in addition, they can modulate the innate immune response. No soluble biomarkers have been discovered that have implications for OA research and PRP interventions. Clinical examination of patients based on their inflammatory phenotype and imaging identification of pain sources and structural alterations could help discern who will respond to PRP. Synovial inflammation and bone marrow lesions are sources of pain, and intra-articular injections of PRP combined with subchondral bone injection can enhance clinical outcomes. Further refining ultrasound phenotypes may aid in personalising PRP therapies. Intra-articular delivery combined with injections in altered ligamentous structures, medial and coronal ligaments or premeniscal pes anserinus showed positive clinical outcomes. Although the evidence supporting these approaches are weak, they merit further consideration to refine PRP protocols and target the right OA phenotypes.

Operative Techniques in Orthopaedics, Jun 1, 2016

Biological interventions, such as ultrasound guided platelet rich plasma (PRP) injections, are a ... more Biological interventions, such as ultrasound guided platelet rich plasma (PRP) injections, are a second line treatment worth considering for recalcitrant tendinopathy, but efficacy and effectiveness have not been established yet. The use of PRP has been most commonly studied in lateral epicondylitis, with nine randomized controlled trials and seven prospective controlled studies in the medical literature. Corticosteroid injection was used as the comparator in six studies, autologous blood in three, and local anesthetic agents in two studies. Recent meta-analyses showed that PRP and autologous blood are superior to corticosteroids in pain reduction and ameliorating functionality in epicondylitis. PRP efficacy on supraspinatus tears are controversial, and PRP is better than controls in two out of five studies, when compared with corticosteroids and dry needling. Patellar tendinopathy is examined in four controlled studies, and eight case series, PRP ameliorated outcomes but not in all cases. Whether more than one injection should be given is under discussion. Achilles tendinopathy was examined in three prospective controlled studies (a single injection), and six case series. Patients showed improvements regarding baseline values, but two controlled studies failed to reveal differences with controls. Pooling data across studies is challenging because of heterogeneity in outcome scores and comparators. Tendinopathy progression and outcomes are poorly monitored with self-reported questionnaires that are not sensitive enough to discriminate local changes. Molecular indicators of tendon health and disease can help to assess whether the condition progress or heal after biological interventions. The international consensus about the design of clinical studies should be pursued.

BioMed Research International, 2014

Platelet-rich plasma (PRP) is injected within tendons to stimulate healing. Metabolic alterations... more Platelet-rich plasma (PRP) is injected within tendons to stimulate healing. Metabolic alterations such as the metabolic syndrome, diabetes, or hyperuricemia could hinder the therapeutic effect of PRP. We hypothesise that tendon cells sense high levels of uric acid and this could modify their response to PRP. Tendon cells were treated with allogeneic PRPs for 96 hours. Hyperuricemic PRP did not hinder the proliferative actions of PRP. The gene expression pattern of inflammatory molecules in response to PRP showed absence of IL-1b and COX1 and modest expression of IL6, IL8, COX2, and TGF-b1. IL8 and IL6 proteins were secreted by tendon cells treated with PRP. The synthesis of IL6 and IL8 proteins induced by PRP is decreased significantly in the presence of hyperuricemia (P = 0.017 and P = 0.012, resp.). Concerning extracellular matrix, PRP-treated tendon cells displayed high type-1 collagen, moderate type-3 collagen, decorin, and hyaluronan synthase-2 expression and modest expression of scleraxis. Hyperuricemia modified the expression pattern of extracellular matrix proteins, upregulating COL1 (P = 0.036) and COMP (P = 0.012) and downregulating HAS2 (P = 0.012). Positive correlations between TGF-b1 and type-1 collagen (R = 0.905, P = 0.002) and aggrecan (R = 0.833, P = 0.010) and negative correlations between TGF-b1 and IL6 synthesis (R = −0.857, P = 0.007) and COX2 (R = −0.810, P = 0.015) were found.

Sports Medicine and Arthroscopy Review

Knee osteoarthritis (OA) is a common condition, prevalent in middle-agedness, associated with chr... more Knee osteoarthritis (OA) is a common condition, prevalent in middle-agedness, associated with chronic pain and impaired quality of life. Two interrelated biological processes fuel early OA progression: inflammation and structural tissues catabolism. Procatabolic and proinflammatory mediators are interconnected and form part of a self-perpetuating loop. They leverage OA research complexity because of the impossibility to discern certain spatiotemporal tissues’ changes from others. Both are shared targets of versatile regenerative multimolecular therapies. In particular, platelet-rich plasma can interfere with inflammation and inflammatory pain. The therapeutic approach is to alter the vicious inflammatory loop by modifying the molecular composition of the synovial fluid, thereby paracrine cellular cross talk. Intra-articular injections of platelet-rich plasma can provide key factors balancing proinflammatory and anti-inflammatory factors, targeting macrophage dysfunction and modulati...

International Journal of Molecular Sciences, 2022

In patients with comorbidities, a large number of wounds become chronic, representing an overwhel... more In patients with comorbidities, a large number of wounds become chronic, representing an overwhelming economic burden for healthcare systems. Engineering the microenvironment is a paramount trend to activate cells and burst-healing mechanisms. The extrusion bioprinting of advanced dressings was performed with novel composite bioinks made by blending adipose decellularized extracellular matrix with plasma and human dermal fibroblasts. Rheological and microstructural assessments of the composite hydrogels supported post-printing cell viability and proliferation over time. Embedded fibroblasts expressed steady concentrations of extracellular matrix proteins, including type 1, 3 and 4 collagens and fibronectin. ELISA assessments, multiplex protein arrays and ensuing bioinformatic analyses revealed paracrine activities corresponding to wound-healing activation through the modulation of inflammation and angiogenesis. The two modalities of advanced dressings, differing in platelet number, ...

Journal of Clinical Medicine, 2022

Platelets and their secretory products play an important role in determining the balance between ... more Platelets and their secretory products play an important role in determining the balance between tissue repair and tissue damage. To obtain novel insights into the molecular composition of platelet-rich plasma (PRP) and contextualize them in knee osteoarthritis (OA), two different plasma formulations, namely PRP and platelet-poor plasma (PPP), were prepared from six healthy donors following a biobank-automated protocol. Inter-donor differences were analyzed, and pools were created before performing multiplexing protein arrays. In addition, PRP and PPP were prepared from six patients following our in-house protocols. Supernatants from PRP and PPP were harvested one hour after calcium chloride activation. Multiplexing protein arrays were performed in parallel for all plasma formulations. Results were normalized to fold change in relation to PPP and examined using Ingenuity Pathway Analysis Software. Bioinformatic predictions showed that PRPs constitute a signaling system with interrel...

Biomedicines, 2021

Extrusion bioprinting based on the development of novel bioinks offers the possibility of manufac... more Extrusion bioprinting based on the development of novel bioinks offers the possibility of manufacturing clinically useful tools for wound management. In this study, we show the rheological properties and printability outcomes of two advanced dressings based on platelet-rich plasma (PRP) and platelet-poor plasma (PPP) blended with alginate and loaded with dermal fibroblasts. Measurements taken at 1 h, 4 days, and 18 days showed that both the PRP- and PPP-based dressings retain plasma and platelet proteins, which led to the upregulation of angiogenic and immunomodulatory proteins by embedded fibroblasts (e.g., an up to 69-fold increase in vascular endothelial growth factor (VEGF), an up to 188-fold increase in monocyte chemotactic protein 1 (MCP-1), and an up to 456-fold increase in hepatocyte growth factor (HGF) 18 days after printing). Conditioned media harvested from both PRP and PPP constructs stimulated the proliferation of human umbilical vein endothelial cells (HUVECs), whereas...

Therapeutic Advances in Musculoskeletal Disease, 2021

Sports injuries and secondary joint problems, mainly of the knee, are common, especially in sport... more Sports injuries and secondary joint problems, mainly of the knee, are common, especially in sports associated with high impact activities and/or torsional loading. The consequences can be career ending in elite athletes and reduce exercise activities in recreational people. Various cell products can be injected intra-articularly. First, fresh cellular mixtures can be prepared and injected in the same day, such as stromal vascular fraction of adipose tissue (SVF) and bone marrow concentrates (BMCs). Second, autologous mesenchymal stromal cells (MSCs) can be isolated from BMCs or SVF and, after several weeks of laboratory expansion, several millions of MSCs can be obtained for intra-articular injection. Finally, allogeneic MSCs from the bone marrow, adipose tissue or perinatal tissues of selected donors constitute an 'off-the-shelf' experimental treatment for injection delivery in patients with osteoarthritis of the knee. The perceived efficacy of all these products is based on the hypothesis of a paracrine mechanism of action: when living cells are delivered within the joint, they establish a molecular cross-talk with immune cells and local cell phenotypes, thereby modulating inflammation with subsequent modifications in the catabolic/degenerative milieu. Current clinical research examines whether injection delivery of MSCs translates into actual clinical benefits. Overall, clinical studies lack the quality needed to answer major research questions, including clinical and structural efficacy, optimal cell dose, and number of injections and specific protocol for cell delivery. Poor experimental designs are exacerbated by the diversity of patient phenotypes that hinder comparisons between treatments. Further understanding of disease pathology is paramount to develop potent function assays and understand whether the host tissue, the cell product or both should be primed before MSCs are injected intra-articularly.

Expert Opinion on Biological Therapy, Sep 27, 2019

Introduction: The heterogeneous pool of cells found in the stromal vascular fraction of adipose t... more Introduction: The heterogeneous pool of cells found in the stromal vascular fraction of adipose tissue (SVF) and the purified mesenchymal stromal/stem cells (ASCs) A c c e p t e d M a n u s c r i p t isolated from this pool have increasingly been used as therapeutic tools in regenerative medicine. Areas covered: As SVF and ASCs are different, and should be used in different manners according to various clinical and biological indications, we reviewed the current literature, and focused on the clinical use of SVF to appraise the main medical fields for development. Both enzymatic digestion and mechanical disruption have been used to obtain SVF for non-homologous use at the point of care. The safety and/or benefits of SVF have been examined in 71 clinical studies in various contexts, mainly musculoskeletal conditions, wound healing, urogenital, and cardiovascular and respiratory diseases. The use of SVF as a therapy remains experimental, with few clinical trials. Expert Opinion: SVF provides a cellular and molecular microenvironment for regulation of ASC' activities under different clinical conditions. SVF may enhance angiogenesis and neovascularization in wound healing, urogenital and cardiovascular diseases. In joint conditions, therapeutic benefits may rely on paracrine immunemodulatory and anti-inflammatory mechanisms. Novel point of care methods are emerging to refine SVF in ways that meet the regulatory requirements for minimal manipulation.

Techniques in Shoulder and Elbow Surgery, Sep 1, 2017

Tendinopathy in upper limb tendons, driven by overuse or understimulation, is very frequent in th... more Tendinopathy in upper limb tendons, driven by overuse or understimulation, is very frequent in the general population. Because of the absence of effective treatments, biological approaches are currently being investigated. Platelet-rich plasma (PRP) is injected locally for the conservative management of epicondylar and rotator cuff tendinopathy, or as a biological enhancer in arthroscopic repair of rotator cuff tears. In epicondylar tendinopathy, we have identified 15 randomized clinical studies comparing the efficacy of PRP with other injectable treatments. PRP has been compared with corticosteroids in 8 randomized trials, showing better results in long-term clinical outcomes; PRP was compared with peripheral blood in 3 studies, showing similar outcomes but fewer adverse effects; 2 studies showed superiority of PRP versus anesthetics using a peppering technique. In 1 study, PRP did not show any clinical efficacy when compared with dry needling, and no efficacy in 2 studies compared with saline injections. Four randomized controlled studies have examined PRP injections in chronic shoulder tendinopathy, but the evidence is inconclusive. PRP as an enhancer of arthroscopic management is questionable but data are evolving as more subgroup analyses become available. PRP therapies have only partially fulfilled therapeutic expectative, and new approaches are necessary.

American Journal of Sports Medicine, May 30, 2014

Background: Intra-articular (IA) treatment with platelet-rich plasma (PRP) for osteoarthritis (OA... more Background: Intra-articular (IA) treatment with platelet-rich plasma (PRP) for osteoarthritis (OA) results in improved patient-reported pain and function scores. Purpose: To measure the effects of PRP and high molecular weight hyaluronan (HA) on the expression of anabolic and catabolic genes and on the secretion of nociceptive and inflammatory mediators from OA cartilage and synoviocytes. Study Design: Controlled laboratory study. Methods: Synovium and cartilage harvested from patients undergoing total knee arthroplasty were co-cultured with media of PRP or HA. Tumor necrosis factor–α (TNF-α), interleukin-6 (IL-6), and IL-1β were measured in the media by enzyme-linked immunosorbent assay. Hyaluronan synthase–2 ( HAS-2), matrix metalloproteinase–1 ( MMP-1), MMP-13, and TNF-α genes were measured in synoviocytes by reverse transcription polymerase chain reaction (RT-PCR). Collagen type I α1 ( COL1A1), COL2A1, aggrecan ( ACAN), and MMP-13 gene expression were measured in cartilage by quantitative RT-PCR. Results: Media TNF-α concentration was decreased in PRP and HA compared with control cultures (PRP = 6.94 pg/mL, HA = 6.39 pg/mL, control = 9.70 pg/mL; P ≤ .05). Media IL-6 concentration was decreased in HA compared with PRP and control (HA = 5027 pg/mL, PRP = 5899 pg/mL, control = 5613 pg/mL; P ≤ .05). Media IL-1β was below detectable concentrations (<0.1 pg/mL) in all samples. Synoviocyte MMP-13 expression was decreased in PRP compared with HA and control (PRP = 10.1, HA = 12.8, control = 13.5; P ≤ .05). Synoviocyte HAS-2 expression was increased in PRP compared with HA and control (PRP = 12.1, HA = 9.8, control = 8.7; P ≤ .05). Cartilage ACAN expression was increased in PRP compared with HA, but neither was different from control (PRP = 8.8, HA = 7.7, control = 7.6; P ≤ .05); COL1A1 expression was increased in HA compared with PRP, but neither was different from control (PRP = 14.9, HA = 13.5, control = 12.9; P ≤ .05). Neither platelet nor leukocyte concentration had a significant effect on outcome measurements (gene or protein expression data) in cartilage or synoviocytes ( P > .05). Conclusion: Both PRP and HA treatments of OA joint tissues result in decreased catabolism, but PRP treatment also resulted in a significant reduction of MMP-13, an increase in HAS-2 expression in synoviocytes, and an increase in cartilage synthetic activity compared with HA. These results indicate that PRP acts to stimulate endogenous HA production and decrease cartilage catabolism. Platelet-rich plasma showed similar effects as HA in the suppression of inflammatory mediator concentration and expression of their genes in synoviocytes and cartilage. Clinical Relevance: The antinociceptive and anti-inflammatory activities of PRP support its use in OA joints to reduce pain and modulate the disease process. This study supports further clinical investigations of IA PRP for the treatment of OA.

Journal of Orthopaedics and Traumatology, Aug 20, 2018

Very often, treatment for many common musculoskeletal conditions is only palliative, or involves ... more Very often, treatment for many common musculoskeletal conditions is only palliative, or involves surgery with major shortcomings. Biological interventions-in particular, platelet-rich plasma (PRP) therapies-may well provide more effective treatments, but their actual efficacy is under scrutiny. PRP is biologically unique to each individual depending on endogenous and exogenous factors, including, but not limited to, demographic factors (i.e. age), immune status (i.e. microbiota), metabolic diseases and concomitant medications. All these potential modifiers of the ultimate effects of PRP have been poorly explored, and their relationship with efficacy has not been established.

Operative Techniques in Orthopaedics, Mar 1, 2012

Knowledge of the basic biological mechanisms involved in tissue response to injury should inform ... more Knowledge of the basic biological mechanisms involved in tissue response to injury should inform management of healing. Approaches to influence healing may need to integrate multiple cell types and large signaling networks that are necessary for the dynamic communication between cells. Platelet-rich plasma (PRP) therapies deliver a myriad of growth factors and cytokines to the injured tissues. Evolution of our understanding of platelet biology and reinterpretation of some of their more traditional roles in hemostasis and tissue repair have revealed much about the complexity of PRP therapies and provide new insights on PRP therapies' successes and failures. However, many potential molecular mechanisms acting simultaneously in tissue repair present a challenge to the identification of critical mechanisms behind PRP therapies. A vast array of barriers, ranging from deficits in basic research to clinical differences in formulations and administration procedures, undermine current efforts to set effective PRP protocols to manage healing. Identifying which molecular mechanisms are more or less important during the course of healing and clarifying the molecular basis for differences in the healing response across patients will continue to be the priority to tailor PRP therapies for particular sports injuries.

Regenerative Medicine, Sep 1, 2018

The positive extensive clinical experience with platelet-rich plasma (PRP) in different medical a... more The positive extensive clinical experience with platelet-rich plasma (PRP) in different medical areas has prompted researchers to explore clinical opportunities for optimized PRP therapies. PRP is safe but we have to make it more effective. The growing diversity of formulations and presentations enrich the field of PRP research and offer hope to refine clinical indications. Moving toward targeting the right disease phenotypes with the right PRP formulation or combination product (PRP + cell products) can offer opportunities to change treatment options in osteoarthritis and nonhealing wounds. Both are active areas of research that could offer opportunities, although cost efficacy is still an open question. Our position is to believe that these serious disease areas are likely to benefit from PRP therapies.

PubMed, 2014

Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PR... more Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) - are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics.

Clinical Orthopaedics and Related Research, May 1, 2015

Background Platelet-rich plasma therapies for tendinopathy appear to provide moderate pain reduct... more Background Platelet-rich plasma therapies for tendinopathy appear to provide moderate pain reduction. However, the biological mechanisms behind the observed clinical effects remain poorly characterized. Questions/purposes The purpose of this study was to explore whether platelet-rich plasma modifies the inflammatory/angiogenic status of already inflamed tenocytes by examining (1) gene expression; (2) modulation of chemokine and interleukin secretion; and (3) differences between healthy and tendinopathic tenocytes. Methods Cells from both healthy and tendinopathic tendons were exposed to interleukin (IL)-1ß and after treated with platelet-rich plasma. Modifications in the expression of selected genes were assessed by real-time reverse transcription-polymerase chain reaction and changes in secretion of angiogenic/inflammatory molecules by enzyme-linked immunosorbent assay. Platelet-rich plasmainduced changes in tendinopathic cells were compared with normal after normalizing platelet-rich plasma data against IL-1ß status in each specific sample. Results In IL-1ß-exposed cells, platelet-rich plasma downregulates expression of IL-6/CXCL-6 (mean, 0.015; 95% confidence interval [CI], 0.005-0.025; p = 0.026), IL-6R (mean, 0.61; 95% CI, 0.27-0.95; p = 0.029), and IL-8/CXCL-8 (mean, 0.02; 95% CI, 0.007-0.023; p = 0.026). Secretion of IL-6/CXCL6, 0.35 (95% CI, 0.3-0.4; p = 0.002), IL-8/CXCL8, 0.55 (95% CI, 0.5-0.7; p = 0.01), and monocyte chemoattractant protein-1/CCL2, 0.40 (95% CI, 0.2-0.6; p = 0.001) was reduced by platelet-rich plasma, whereas vascular endothelial growth factor increased by twofold, (95% CI, 1.7-2.3; p \ 0.001). RANTES/CCL5 increased by10-fold (95% CI, 4-17) and hepatocyte growth factor by 21-fold (95% CI, 0.2-42) in tendinopathic and by 2.3-fold (95% CI, 2-3) and threefold (95% CI, 1-5) in normal cells (p = 0.005 for both). Conclusions Platelet-rich plasma induces an immunomodulatory and proangiogenic phenotype consistent with healing mechanisms with few differences between tendinopathic and normal cells. Clinical Relevance Platelet-rich plasma injections in pathological and nearby tissue might help to recover tendon homeostasis. The Department of Industry from the Basque Government provided financial support, SAIO2012-PE12BF007. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.

Expert Opinion on Biological Therapy, Dec 15, 2011

At the beginning of the new millennium, there was a breakthrough in platelet-rich plasma (PRP) th... more At the beginning of the new millennium, there was a breakthrough in platelet-rich plasma (PRP) therapy for tissue repair. The mechanisms governing the effects of this therapy in joint pathology remain largely unexplored. This review is primarily based on PubMed and Web of Knowledge searches with the terms osteoarthritis in combination with PRP, treatment, cartilage, synovium, platelets, inflammation and/or angiogenesis. This search was completed by a manual search for relevant studies. We mainly include papers from the last 5 years. The concept of dynamic reciprocity is used to shape understanding of the spatial relationship between cells and their microenvironments as well as between tissues within the joint. We describe the processes of joint injury and pathology relevant to the mechanism of action of PRP, and elaborate insights into how PRP components may influence inflammation, angiogenesis, cell death and cartilage chondroprotection. PRP therapies are more complicated than previously acknowledged, and an understanding of the fundamental processes and pivotal molecules involved will hopefully be elucidated soon. This challenge is to provide a comprehensive description of the relationship between PRP components, healing mechanisms and clinical outcomes. Although PRP therapies in clinical trials await assessment, they have shed light on new avenues of management because of their effects on repair functions.

Expert Opinion on Biological Therapy, Aug 18, 2010

The therapeutic use of platelet-rich plasma (PRP) is an autologous biotechnology that relies on t... more The therapeutic use of platelet-rich plasma (PRP) is an autologous biotechnology that relies on the local delivery of a wide range of growth factors and cytokines with the aim of enhancing tissue healing. Understanding both tendon healing and PRP therapies is an area of research that is critically important in developing optimal formulations and protocols to achieve the intended therapeutic effects. We summarise recent information on the mechanisms inherent to the earliest response to tendon injury. We then describe the positive effect of PRP therapies on tendon healing. Research on tendinopathy has produced several biological hypotheses based on histopathological, biochemical and clinical findings showing that cell apoptosis, angiofibroblastic features or abnormal biochemical adaptations underlie the condition. The article provides insights into early healing mechanisms and the influence of PRP therapies on inflammation, cell migration, angiogenesis and the proliferation and synthesis of extracellular matrix. The knowledge gained helps to better understand and optimize tendon therapies. The use of endogenous therapies has a positive effect on experimental tendon healing. However, several obstacles need to be addressed to optimise medical practice in this field.

Osteoarthritis (OA) is a common disease involving joint damage, an inadequate healing response an... more Osteoarthritis (OA) is a common disease involving joint damage, an inadequate healing response and progressive deterioration of the joint architecture. Autologous blood-derived products such as platelet- rich plasma (PRP) are key sources of molecules involved in tissue repair and regeneration. In pathological conditions such as OA, these products can deliver a collection of bioactive molecules that have important roles in fundamental processes, including inflammation, angiogenesis, cell migration and metabolism. PRP has anti-inflammatory properties through its effects on the canonical nuclear factor κ B signalling pathway in multiple cell types including synoviocytes, macrophages and chondrocytes. PRP contains thousands of different molecules; cells within the joint add to this milieu by secreting additional biologically active molecules in response to PRP. The net results of PRP therapy are varied and can include angiogenesis, the production of local conditions that favour anabolism in the articular cartilage, or the recruitment of repair cells. However, the molecules found in PRP that contribute to angiogenesis and the protection of joint integrity need further clarification. Understanding PRP in molecular terms could help us to exploit its therapeutic potential, and aid the development of novel treatments and tissue-engineering approaches, for the different stages of joint degeneration.

Therapeutic Advances in Musculoskeletal Disease, 2021

Intra-articular injections of platelet-rich plasma (PRP) and other novel bloodderived products de... more Intra-articular injections of platelet-rich plasma (PRP) and other novel bloodderived products developed specifically for osteoarthritis (OA) can provide pain relief and potential benefits in disease progression. Meta-analyses show the clinical superiority of PRP compared with other intra-articular injections, but results are modest and the effect sizes are small. PRP injections in knee OA are performed indiscriminately, but the clinical response varies enormously between patients because of an array of mixed OA phenotypes. Subgroup analyses are scarce; some studies stratify patients according to radiographic severity and found better results in early OA, without consensus for more advanced stages of the condition. Parallel identification of soluble and imaging biomarkers is essential to personalise and leverage PRP therapies. The inflammatory phenotype is most interesting from the PRP perspective because PRPs modulate inflammation by releasing a large pool of chemokines and cytokines, which interact with synovial fibroblasts and macrophages; in addition, they can modulate the innate immune response. No soluble biomarkers have been discovered that have implications for OA research and PRP interventions. Clinical examination of patients based on their inflammatory phenotype and imaging identification of pain sources and structural alterations could help discern who will respond to PRP. Synovial inflammation and bone marrow lesions are sources of pain, and intra-articular injections of PRP combined with subchondral bone injection can enhance clinical outcomes. Further refining ultrasound phenotypes may aid in personalising PRP therapies. Intra-articular delivery combined with injections in altered ligamentous structures, medial and coronal ligaments or premeniscal pes anserinus showed positive clinical outcomes. Although the evidence supporting these approaches are weak, they merit further consideration to refine PRP protocols and target the right OA phenotypes.

Operative Techniques in Orthopaedics, Jun 1, 2016

Biological interventions, such as ultrasound guided platelet rich plasma (PRP) injections, are a ... more Biological interventions, such as ultrasound guided platelet rich plasma (PRP) injections, are a second line treatment worth considering for recalcitrant tendinopathy, but efficacy and effectiveness have not been established yet. The use of PRP has been most commonly studied in lateral epicondylitis, with nine randomized controlled trials and seven prospective controlled studies in the medical literature. Corticosteroid injection was used as the comparator in six studies, autologous blood in three, and local anesthetic agents in two studies. Recent meta-analyses showed that PRP and autologous blood are superior to corticosteroids in pain reduction and ameliorating functionality in epicondylitis. PRP efficacy on supraspinatus tears are controversial, and PRP is better than controls in two out of five studies, when compared with corticosteroids and dry needling. Patellar tendinopathy is examined in four controlled studies, and eight case series, PRP ameliorated outcomes but not in all cases. Whether more than one injection should be given is under discussion. Achilles tendinopathy was examined in three prospective controlled studies (a single injection), and six case series. Patients showed improvements regarding baseline values, but two controlled studies failed to reveal differences with controls. Pooling data across studies is challenging because of heterogeneity in outcome scores and comparators. Tendinopathy progression and outcomes are poorly monitored with self-reported questionnaires that are not sensitive enough to discriminate local changes. Molecular indicators of tendon health and disease can help to assess whether the condition progress or heal after biological interventions. The international consensus about the design of clinical studies should be pursued.

BioMed Research International, 2014

Platelet-rich plasma (PRP) is injected within tendons to stimulate healing. Metabolic alterations... more Platelet-rich plasma (PRP) is injected within tendons to stimulate healing. Metabolic alterations such as the metabolic syndrome, diabetes, or hyperuricemia could hinder the therapeutic effect of PRP. We hypothesise that tendon cells sense high levels of uric acid and this could modify their response to PRP. Tendon cells were treated with allogeneic PRPs for 96 hours. Hyperuricemic PRP did not hinder the proliferative actions of PRP. The gene expression pattern of inflammatory molecules in response to PRP showed absence of IL-1b and COX1 and modest expression of IL6, IL8, COX2, and TGF-b1. IL8 and IL6 proteins were secreted by tendon cells treated with PRP. The synthesis of IL6 and IL8 proteins induced by PRP is decreased significantly in the presence of hyperuricemia (P = 0.017 and P = 0.012, resp.). Concerning extracellular matrix, PRP-treated tendon cells displayed high type-1 collagen, moderate type-3 collagen, decorin, and hyaluronan synthase-2 expression and modest expression of scleraxis. Hyperuricemia modified the expression pattern of extracellular matrix proteins, upregulating COL1 (P = 0.036) and COMP (P = 0.012) and downregulating HAS2 (P = 0.012). Positive correlations between TGF-b1 and type-1 collagen (R = 0.905, P = 0.002) and aggrecan (R = 0.833, P = 0.010) and negative correlations between TGF-b1 and IL6 synthesis (R = −0.857, P = 0.007) and COX2 (R = −0.810, P = 0.015) were found.

Sports Medicine and Arthroscopy Review

Knee osteoarthritis (OA) is a common condition, prevalent in middle-agedness, associated with chr... more Knee osteoarthritis (OA) is a common condition, prevalent in middle-agedness, associated with chronic pain and impaired quality of life. Two interrelated biological processes fuel early OA progression: inflammation and structural tissues catabolism. Procatabolic and proinflammatory mediators are interconnected and form part of a self-perpetuating loop. They leverage OA research complexity because of the impossibility to discern certain spatiotemporal tissues’ changes from others. Both are shared targets of versatile regenerative multimolecular therapies. In particular, platelet-rich plasma can interfere with inflammation and inflammatory pain. The therapeutic approach is to alter the vicious inflammatory loop by modifying the molecular composition of the synovial fluid, thereby paracrine cellular cross talk. Intra-articular injections of platelet-rich plasma can provide key factors balancing proinflammatory and anti-inflammatory factors, targeting macrophage dysfunction and modulati...

International Journal of Molecular Sciences, 2022

In patients with comorbidities, a large number of wounds become chronic, representing an overwhel... more In patients with comorbidities, a large number of wounds become chronic, representing an overwhelming economic burden for healthcare systems. Engineering the microenvironment is a paramount trend to activate cells and burst-healing mechanisms. The extrusion bioprinting of advanced dressings was performed with novel composite bioinks made by blending adipose decellularized extracellular matrix with plasma and human dermal fibroblasts. Rheological and microstructural assessments of the composite hydrogels supported post-printing cell viability and proliferation over time. Embedded fibroblasts expressed steady concentrations of extracellular matrix proteins, including type 1, 3 and 4 collagens and fibronectin. ELISA assessments, multiplex protein arrays and ensuing bioinformatic analyses revealed paracrine activities corresponding to wound-healing activation through the modulation of inflammation and angiogenesis. The two modalities of advanced dressings, differing in platelet number, ...

Journal of Clinical Medicine, 2022

Platelets and their secretory products play an important role in determining the balance between ... more Platelets and their secretory products play an important role in determining the balance between tissue repair and tissue damage. To obtain novel insights into the molecular composition of platelet-rich plasma (PRP) and contextualize them in knee osteoarthritis (OA), two different plasma formulations, namely PRP and platelet-poor plasma (PPP), were prepared from six healthy donors following a biobank-automated protocol. Inter-donor differences were analyzed, and pools were created before performing multiplexing protein arrays. In addition, PRP and PPP were prepared from six patients following our in-house protocols. Supernatants from PRP and PPP were harvested one hour after calcium chloride activation. Multiplexing protein arrays were performed in parallel for all plasma formulations. Results were normalized to fold change in relation to PPP and examined using Ingenuity Pathway Analysis Software. Bioinformatic predictions showed that PRPs constitute a signaling system with interrel...

Biomedicines, 2021

Extrusion bioprinting based on the development of novel bioinks offers the possibility of manufac... more Extrusion bioprinting based on the development of novel bioinks offers the possibility of manufacturing clinically useful tools for wound management. In this study, we show the rheological properties and printability outcomes of two advanced dressings based on platelet-rich plasma (PRP) and platelet-poor plasma (PPP) blended with alginate and loaded with dermal fibroblasts. Measurements taken at 1 h, 4 days, and 18 days showed that both the PRP- and PPP-based dressings retain plasma and platelet proteins, which led to the upregulation of angiogenic and immunomodulatory proteins by embedded fibroblasts (e.g., an up to 69-fold increase in vascular endothelial growth factor (VEGF), an up to 188-fold increase in monocyte chemotactic protein 1 (MCP-1), and an up to 456-fold increase in hepatocyte growth factor (HGF) 18 days after printing). Conditioned media harvested from both PRP and PPP constructs stimulated the proliferation of human umbilical vein endothelial cells (HUVECs), whereas...