Bone grafts and biomaterials substitutes for bone defect repair: A review.

A substantial body of evidence supports that the gut microbiota plays a pivotal role in the regulation of metabolic, endocrine and immune functions. In recent years, there has been growing recognition of the involvement of the gut microbiota in the modulation of multiple neurochemical pathways through the highly interconnected gut-brain axis. Although amazing scientific breakthroughs over the last few years have expanded our knowledge on the communication between microbes and their hosts, the underpinnings of microbiota-gut-brain crosstalk remain to be determined. Short-chain fatty acids (SCFAs), the main metabolites produced in the colon by bacterial fermentation of dietary fibers and resistant starch, are speculated to play a key role in neuro-immunoendocrine regulation. However, the underlying mechanisms through which SCFAs might influence brain physiology and behavior have not been fully elucidated. In this review, we outline the current knowledge about the involvement of SCFAs in microbiota-gut-brain interactions. We also highlight how the development of future treatments for central nervous system (CNS) disorders can take advantage of the intimate and mutual interactions of the gut microbiota with the brain by exploring the role of SCFAs in the regulation of neuro-immunoendocrine function.

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The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication

Platelet-rich plasma (PRP) is nowadays widely applied in different clinical scenarios, such as orthopedics, ophthalmology and healing therapies, as a growth factor pool for improving tissue regeneration. Studies into its clinical efficiency are not conclusive and one of the main reasons for this is that different PRP preparations are used, eliciting different responses that cannot be compared. Platelet quantification and the growth factor content definition must be defined in order to understand molecular mechanisms behind PRP regenerative strength. Standardization of PRP preparations is thus urgently needed. PRP was prepared by centrifugation varying the relative centrifugal force, temperature, and time. Having quantified platelet recovery and yield, the two-step procedure that rendered the highest output was chosen and further analyzed. Cytokine content was determined in different fractions obtained throughout the whole centrifugation procedure. Our method showed reproducibility when applied to different blood donors. We recovered 46.9 to 69.5% of total initial platelets and the procedure resulted in a 5.4-fold to 7.3-fold increase in platelet concentration (1.4 × 106 to 1.9 × 106 platelets/μl). Platelets were highly purified, because only <0.3% from the initial red blood cells and leukocytes was present in the final PRP preparation. We also quantified growth factors, cytokines and chemokines secreted by the concentrated platelets after activation with calcium and calcium/thrombin. High concentrations of platelet-derived growth factor, endothelial growth factor and transforming growth factor (TGF) were secreted, together with the anti-inflammatory and proinflammatory cytokines interleukin (IL)-4, IL-8, IL-13, IL-17, tumor necrosis factor (TNF)-α and interferon (IFN)-α. No cytokines were secreted before platelet activation. TGF-β3 and IFNγ were not detected in any studied fraction. Clots obtained after platelet coagulation retained a high concentration of several growth factors, including platelet-derived growth factor and TGF. Our study resulted in a consistent PRP preparation method that yielded a cytokine and growth factor pool from different donors with high reproducibility. These findings support the use of PRP in therapies aiming for tissue regeneration, and its content characterization will allow us to understand and improve the clinical outcomes.

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Platelet-rich plasma preparation for regenerative medicine: optimization and quantification of cytokines and growth factors

Purpose Platelet-rich plasma (PRP) therapy is a simple, low-cost and minimally invasive method that provides a natural concentrate of autologous blood growth factors (GFs) that can be used to enhance tissue regeneration. In a previous analysis of a 12-month follow-up study, promising results were obtained when treating patients affected by knee degeneration with PRP intra-articular injections. The main purpose of this study was to investigate the persistence of the beneficial effects observed. Methods Of the 91 patients evaluated in the previous 12-month follow-up study, 90 were available for the 2-year follow-up (24 patients presented a bilateral lesion, in a total of 114 knees treated). All of the patients presented a chronic knee degenerative condition and were treated with three intra-articular PRP injections. IKDC and EQ-VAS scores were used for clinical evaluation. Complications, adverse events and patient satisfaction were also recorded. Results All of the evaluated parameters worsened at the 24-month follow-up: these parameters were at significantly lower levels with respect to the 12-month evaluation (the IKDC objective evaluation fell from 67 to 59% of normal and nearly normal knees; the IKDC subjective score fell from 60 to 51), even if they remained higher than the basal level. Further analysis showed better results in younger patients (P = 0.0001) and lower degrees of cartilage degeneration (P \ 0.0005). The median duration of the clinical improvement was 9 months. Conclusions These findings indicate that treatment with PRP injections can reduce pain and improve knee function and quality of life with short-term efficacy. Further studies are needed to confirm these results and understand the mechanism of action, and to find other application modalities, with different platelet and GF concentrations and injection timing, which provide better and more durable results.

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Platelet-rich plasma intra-articular knee injections for the treatment of degenerative cartilage lesions and osteoarthritis

Platelet concentrates such as platelet-rich plasma (PRP) have gained popularity in sports medicine and orthopaedics to promote accelerated physiologic healing and return to function. Each PRP product varies depending on patient factors and the system used to generate it. Blood from some patients may fail to make PRP, and most clinicians use PRP without performing cell counts on either the blood or the preparation to confirm that the solution is truly PRP. Components in this milieu have bioactive functions that affect musculoskeletal tissue regeneration and healing. Platelets are activated by collagen or other molecules and release growth factors from alpha granules. Additional substances are released from dense bodies and lysosomes. Soluble proteins also present in PRP function in hemostasis, whereas others serve as biomarkers of musculoskeletal injury. Electrolytes and soluble plasma hormones are required for cellular signaling and regulation. Leukocytes and erythrocytes are present in PRP and function in inflammation, immunity, and additional cellular signaling pathways. This article supports the emerging paradigm that more than just platelets are playing a role in clinical responses to PRP. Depending on the specific constituents of a PRP preparation, the clinical use can theoretically be matched to the pathology being treated in an effort to improve clinical efficacy.

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Platelet-rich plasma: a milieu of bioactive factors.

Platelet-rich plasma (PRP) has been utilized in surgery for 2 decades; there has been a recent interest in the use of PRP for the treatment of sports-related injuries. PRP contains growth factors and bioactive proteins that influence the healing of tendon, ligament, muscle, and bone. This article examines the basic science of PRP, and it describes the current clinical applications in sports medicine. This study reviews and evaluates the human studies that have been published in the orthopaedic surgery and sports medicine literature. The use of PRP in amateur and professional sports is reviewed, and the regulation of PRP by antidoping agencies is discussed.

Platelet-Rich Plasma From Basic Science to Clinical Applications

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From Basic Science to Clinical Applications

Background: The advantage of single-row versus double-row arthroscopic rotator cuff repair techniques has been a controversial issue in sports medicine and shoulder surgery. There is biomechanical evidence that double-row techniques are superior to single-row techniques; however, there is no clinical evidence that the double-row technique provides an improved functional outcome.Hypothesis: When compared with single-row rotator cuff repair, double-row fixation, although biomechanically superior, has no clinical benefit with respect to retear rate or improved functional outcome.Study Design: Systematic review.Methods: The authors reviewed prospective studies of level I or II clinical evidence that compared the efficacy of single- and double-row rotator cuff repairs. Functional outcome scores included the American Shoulder and Elbow Surgeons (ASES) shoulder scale, the Constant shoulder score, and the University of California, Los Angeles (UCLA) shoulder rating scale. Radiographic failures and complications w...

Brian L. Puskas

Papers

Platelet-Rich Plasma From Basic Science to Clinical Applications

From Basic Science to Clinical Applications

Does Double-Row Rotator Cuff Repair Improve Functional Outcome of Patients Compared With Single-Row Technique? A Systematic Review