Personalized plasma-based medicine to treat age-related diseases

Effectiveness of platelet derivatives in neuropathic pain management: A systematic review

BACKGROUND

Neuropathic pain (NP) has a considerable impact on the global economic burden and seriously impairs patients' quality of life. Currently there is no evidence-based "effective" treatment and new treatments are needed. Recently, platelet rich plasma (PRP) has emerged as an alternative treatment. Therefore, a systematic review has been conducted to present an evidence-based assessment of the use of PRP in the treatment of NP.

METHODS

Randomized studies that investigated the effect of PRP injection on patients with NP compared to alternative treatments or placebo were included. An encompassing search of specific databases, from their inception to April 2024, was performed. The databases were as follows: PubMed, Web of Sciences (MEDLINE) and Cochrane Library. The Cochrane Risk-of-Bias 2 tool was used to assess study methodological quality.

RESULTS

A total of 12 randomized studies with 754 patients with different NP conditions were included in this systematic review. According to the results from the qualitative analysis, PRP injection exerted a positive effect on improving pain intensity on most of the trials (8 out of 12). In the remaining studies, no differences were found. A high safety profile was reported with no serious adverse effects in the analysed patients.

CONCLUSION

PRP treatment might be an effective therapeutic approach for patients with different neuropathic pain conditions. The efficacy of PRP was not dependant on the aetiology of the underlying disorder; nevertheless, interpretations of the results should be performed cautiously, as for the under-representation of NP conditions.

Immunoregulatory role of platelet derivatives in the macrophage-mediated immune response

Background

Macrophages are innate immune cells that display remarkable phenotypic heterogeneity and functional plasticity. Due to their involvement in the pathogenesis of several human conditions, macrophages are considered to be an attractive therapeutic target. In line with this, platelet derivatives have been successfully applied in many medical fields and as active participants in innate immunity, cooperation between platelets and macrophages is essential. In this context, the aim of this review is to compile the current evidence regarding the effects of platelet derivatives on the phenotype and functions of macrophages to identify the advantages and shortcomings for feasible future clinical applications.

Methods

A total of 669 articles were identified during the systematic literature search performed in PubMed and Web of Science databases.

Results

A total of 27 articles met the inclusion criteria. Based on published findings, platelet derivatives may play an important role in inducing a dynamic M1/M2 balance and promoting a timely M1-M2 shift. However, the differences in procedures regarding platelet derivatives and macrophages polarization and the occasional lack of information, makes reproducibility and comparison of results extremely challenging. Furthermore, understanding the differences between human macrophages and those derived from animal models, and taking into account the peculiarities of tissue resident macrophages and their ontogeny seem essential for the design of new therapeutic strategies.

Conclusion

Research on the combination of macrophages and platelet derivatives provides relevant information on the function and mechanisms of the immune response.

Advances in Platelet Rich Plasma-Derived Extracellular Vesicles for Regenerative Medicine: A Systematic-Narrative Review

The use of platelet-rich plasma (PRP) has gained increasing interest in recent decades. The platelet secretome contains a multitude of growth factors, cytokines, chemokines, and other biological biomolecules. In recent years, developments in the field of platelets have led to new insights, and attention has been focused on the platelets' released extracellular vesicles (EVs) and their role in intercellular communication. In this context, the aim of this review was to compile the current evidence on PRP-derived extracellular vesicles to identify the advantages and limitations fortheir use in the upcoming clinical applications. A total of 172 articles were identified during the systematic literature search through two databases (PubMed and Web of Science). Twenty publications met the inclusion criteria and were included in this review. According to the results, the use of PRP-EVs in the clinic is an emerging field of great interest that represents a promising therapeutic option, as their efficacy has been demonstrated in the majority of fields of applications included in this review. However, the lack of standardization along the procedures in both the field of PRP and the EVs makes it extremely challenging to compare results among studies. Establishing standardized conditions to ensure optimized and detailed protocols and define parameters such as the dose or the EV origin is therefore urgent. Further studies to elucidate the real contribution of EVs to PRP in terms of composition and functionality should also be performed. Nevertheless, research on the field provides promising results and a novel basis to deal with the regenerative medicine and drug delivery fields in the future.

Composite alginate-gelatin hydrogels incorporating PRGF enhance human dental pulp cell adhesion, chemotaxis and proliferation

The increasing prevalence of tissue injuries is fueling the development of autologous biological treatments for regenerative medicine. Here, we investigated the potential of three different bioinks based on the combination of gelatin and alginate (GA), enriched in either hydroxyapatite (GAHA) or hydroxyapatite and PRGF (GAHAP), as a favorable microenvironment for human dental pulp stem cells (DPSCs). Swelling behaviour, in vitro degradation and mechanical properties of the matrices were evaluated. Morphological and elemental analysis of the scaffolds were also performed along with cytocompatibility studies. The in vitro cell response to the different scaffolds was also assessed. Results showed that all scaffolds presented high swelling capacity, and those that contained HA showed higher Young's modulus. GAHAP had the lowest degradation rate and the highest values of cytocompatibility. Cell adhesion and chemotaxis were significantly increased when PRGF was incorporated to the matrices. GAHA and GAHAP compositions promoted the highest proliferative rate as well as significantly stimulated osteogenic differentiation. In conclusion, the enrichment with PRGF improves the regenerative properties of the composites favouring the development of personalized constructs.

Of vascular defense, hemostasis, cancer, and platelet biology: an evolutionary perspective

We have established considerable expertise in studying the role of platelets in cancer biology. From this expertise, we were keen to recognize the numerous venous-, arterial-, microvascular-, and macrovascular thrombotic events and immunologic disorders are caused by severe, acute-respiratory-syndrome coronavirus 2 (SARS-CoV-2) infections. With this offering, we explore the evolutionary connections that place platelets at the center of hemostasis, immunity, and adaptive phylogeny. Coevolutionary changes have also occurred in vertebrate viruses and their vertebrate hosts that reflect their respective evolutionary interactions. As mammals adapted from aquatic to terrestrial life and the heavy blood loss associated with placentalization-based live birth, platelets evolved phylogenetically from thrombocytes toward higher megakaryocyte-blebbing-based production rates and the lack of nuclei. With no nuclei and robust RNA synthesis, this adaptation may have influenced viral replication to become less efficient after virus particles are engulfed. Human platelets express numerous receptors that bind viral particles, which developed from archetypal origins to initiate aggregation and exocytic-release of thrombo-, immuno-, angiogenic-, growth-, and repair-stimulatory granule contents. Whether by direct, evolutionary, selective pressure, or not, these responses may help to contain virus spread, attract immune cells for eradication, and stimulate angiogenesis, growth, and wound repair after viral damage. Because mammalian and marsupial platelets became smaller and more plate-like their biophysical properties improved in function, which facilitated distribution near vessel walls in fluid-shear fields. This adaptation increased the probability that platelets could then interact with and engulf shedding virus particles. Platelets also generate circulating microvesicles that increase membrane surface-area encounters and mark viral targets. In order to match virus-production rates, billions of platelets are generated and turned over per day to continually provide active defenses and adaptation to suppress the spectrum of evolving threats like SARS-CoV-2.

The interplay of fibroblasts, the extracellular matrix, and inflammation in scar formation

Various forms of fibrosis, comprising tissue thickening and scarring, are involved in 40% of deaths across the world. Since the discovery of scarless functional healing in fetuses prior to a certain stage of development, scientists have attempted to replicate scarless wound healing in adults with little success. While the extracellular matrix (ECM), fibroblasts, and inflammatory mediators have been historically investigated as separate branches of biology, it has become increasingly necessary to consider them as parts of a complex and tightly regulated system that becomes dysregulated in fibrosis. With this new paradigm, revisiting fetal scarless wound healing provides a unique opportunity to better understand how this highly regulated system operates mechanistically. In the following review, we navigate the four stages of wound healing (hemostasis, inflammation, repair, and remodeling) against the backdrop of adult versus fetal wound healing, while also exploring the relationships between the ECM, effector cells, and signaling molecules. We conclude by singling out recent findings that offer promising leads to alter the dynamics between the ECM, fibroblasts, and inflammation to promote scarless healing. One factor that promises to be significant is fibroblast heterogeneity and how certain fibroblast subpopulations might be predisposed to scarless healing. Altogether, reconsidering fetal wound healing by examining the interplay of the various factors contributing to fibrosis provides new research directions that will hopefully help us better understand and address fibroproliferative diseases, such as idiopathic pulmonary fibrosis, liver cirrhosis, systemic sclerosis, progressive kidney disease, and cardiovascular fibrosis.

The inclusion of leukocytes into platelet rich plasma reduces scaffold stability and hinders extracellular matrix remodelling

BACKGROUND

Scaffolds should have controllable degradation rate and allow cells to produce their own extracellular matrix. Platelet rich plasma (PRP) is a source of autologous growth factors and proteins embedded in a 3D fibrin scaffold. There is no consensus regarding the obtaining conditions and composition of PRPs. The aim of this study was to evaluate how the inclusion of leukocytes (L-PRP) in plasma rich in growth factors (PRGF) may alter the process of fibrinolysis. The effect of different combinations of cellular phenotypes with PRGF and L-PRP clots on both the fibrinolysis and matrix deposition process was also determined.

METHODS

PRGF and L-PRP clots were incubated for 14 days and D-dimer and type I collagen were determined in their conditioned media to evaluate clots' stability. For remodelling assays, gingival fibroblasts, alveolar osteoblasts and human umbilical vein endothelial cells (HUVEC) were seeded onto the two types of clots for 14 days. D-dimer, type I collagen, and laminin α4 were measured by ELISA kits in their conditioned media. Morphological and histological analysis were also performed. Cell proliferation was additionally determined RESULTS: PRGF clots preserved their stability as shown by the low levels of both D-dimer and collagen type I compared to those obtained for L-PRP clots. The inclusion of both gingival fibroblasts and alveolar osteoblasts stimulated a higher fibrinolysis in the PRGF clots. In contrast to this, the degradation rates of both PRGF and L-PRP clots remained unchanged after culturing with the endothelial cells. In all cases, type I collagen and laminin α4 levels were in line with the degree of clots' degradation. In all phenotypes, cell proliferation was significantly higher in PRGF than in L-PRP clots.

CONCLUSION

The inclusion of leukocytes in PRGF scaffolds reduced their stability, decreased cell number and slowed down cell remodelling.

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.

The influence of sodium citrate on the characteristics and biological activity of plasma rich in growth factors

Aim: This study investigated the effect of sodium citrate on the properties and biological activity of plasma rich in growth factors (PRGF). Methods: PRGF was obtained from trisodium citrate and plain extraction tubes. Hematological parameters, growth factors' release kinetics from both PRGF clots and their releasates' biological effect on human bone cells were evaluated. Results: The platelet enrichment factor, the growth factors' content and the release kinetic of PRGF were similar for both groups. The proliferation, collagen type I synthesis and tissue-nonspecific alkaline phosphatase activity of human osteoblasts showed no statistically significant differences. Conclusion: The use of sodium citrate does not influence the composition, the growth factors' release kinetics or the biological effect of PRGF, but it increases its clinical versatility.

Vertebral intraosseous plasma rich in growth factor (PRGF-Endoret) infiltrations as a novel strategy for the treatment of degenerative lesions of endplate in lumbar pathology: description of technique and case presentation

BACKGROUND

Motivation and necessity to adopt minimally invasive therapies in the field of spinal regenerative medicine is increasing. Autologous platelet-rich plasma (PRP) therapy has recently been used as an effective technological and biological approach to tissue repair and has shown to improve multiple conditions including back pain and degenerative disc pathology. In addition, it is well established that the anatomic elements of the spinal system affected by degenerative pathology include the intervertebral disc (IVD) and vertebral subchondral bone (VSB), which play a crucial role in maintaining a healthy spinal column. Both elements are the target of a novel biological approach to the treatment of low back pain.

METHODS

A novel minimally invasive regenerative therapeutic approach is presented herein with a protocol based on combining vertebral intraosseous (VIO) and intradiscal (ID) infiltrations of plasma rich in growth factors (PRGF-Endoret), a type of leukocyte-free PRP, for the treatment of disc degeneration pathology.

RESULTS

We describe a novel technique applied in a patient treated for IVD degeneration and VSB damage, showing significant improvement on magnetic resonance imaging, including partial regression of protruded disc and significant resorption of intravertebral herniations (Schmörl's nodes), after PRGF therapy.

CONCLUSIONS

To the best of our knowledge, we present the first reported case description of the utilization of VIO and ID PRP infiltrations to treat protruded discs and intravertebral herniations with a successful clinical outcome.

Platelet Concentrates in Musculoskeletal Medicine

Platelet concentrates (PCs), mostly represented by platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous biological blood-derived products that may combine plasma/platelet-derived bioactive components, together with fibrin-forming protein able to create a natural three-dimensional scaffold. These types of products are safely used in clinical applications due to the autologous-derived source and the minimally invasive application procedure. In this narrative review, we focus on three main topics concerning the use of platelet concentrate for treating musculoskeletal conditions: (a) the different procedures to prepare PCs, (b) the composition of PCs that is related to the type of methodological procedure adopted and (c) the clinical application in musculoskeletal medicine, efficacy and main limits of the different studies.

Glycaemic control in diabetic rats treated with islet transplantation using plasma combined with hydroxypropylmethyl cellulose hydrogel

Islet transplantation is one of the most efficient cell therapies used in clinics and could treat a large proportion of patients with diabetes. However, it is limited by the high requirement of pancreas necessary to provide the sufficient surviving islet mass in the hepatic tissue and restore normoglycaemia. Reduction in organ procurement requirements could be achieved by extrahepatic transplantation using a biomaterial that enhances islet survival and function. We report a plasma-supplemented hydroxypropyl methylcellulose (HPMC) hydrogel, engineered specifically using a newly developed technique for intra-omental islet infusion, known as hOMING (h-Omental Matrix Islet filliNG). The HPMC hydrogel delivered islets with better performance than that of the classical intrahepatic infusion. After the validation of the HPMC suitability for islets in vivo and in vitro, plasma supplementation modified the rheological properties of HPMC without affecting its applicability with hOMING. The biomaterial association was proven to be more efficient both in vitro and in vivo, with better islet viability and function than that of the current clinical intrahepatic delivery technique. Indeed, when the islet mass was decreased by 25% or 35%, glycaemia control was observed in the group of plasma-supplemented hydrogels, whereas no regulation was observed in the hepatic group. Plasma gelation, observed immediately post infusion, decreased anoïkis and promoted vascularisation. To conclude, the threshold mass for islet transplantation could be decreased using HPMC-Plasma combined with the hOMING technique. The simplicity of the hOMING technique and the already validated use of its components could facilitate its transfer to clinics. STATEMENT OF SIGNIFICANCE: One of the major limitations for the broad deployment of current cell therapy for brittle type 1 diabetes is the islets' destruction during the transplantation process. Retrieved from their natural environment, the islets are grafted into a foreign tissue, which triggers massive cell loss. It is mandatory to provide the islets with an 3D environment specifically designed for promoting isletimplantation to improve cell therapy outcomes. For this aim, we combined HPMC and plasma. HPMC provides suitable rheological properties to the plasma to be injectable and be maintained in the omentum. Afterwards, the plasma polymerises around the graft in vivo, thereby allowing their optimal integration into their transplantation site. As a result, the islet mass required to obtain glycaemic control was reduced by 35%.

Autologous platelet-rich gel for facial rejuvenation and wrinkle amelioration: A pilot study

BACKGROUND

The demand for safe and minimally invasive soft tissue augmentation procedures has increased. Recently, a novel injectable gel based on the autologous platelet rich in growth factor (PRGF) technology has been developed to provide long-term shape and volume stability. It can be customized into low (LVG) or high viscosity (HVG) gel forms to meet different dermatological requirements.

OBJECTIVES

The mechanical and biological properties of both gel forms have been evaluated. The clinical efficacy and safety of this autologous procedure were also evaluated.

METHODS

Growth factor content and biomechanical properties of both gel forms were determined. The in vitro biological capacity on human dermal fibroblasts proliferation was assessed. Clinical performance analysis over ten patients was evaluated by standardized macrophotographs, 3D topographic images, and ultrasound analysis over periocular and nasolabial areas.

RESULTS

Both gel types showed similar growth factor concentration. HVG showed a higher stiffness profile indicating its suitability for deeper tissue defect viscosupplementation while LVG showed optimal rheologic characteristics for superficial volumization. Both gels showed a noticeable biostability after catalytic enzyme degradation. Both forms significantly increased the mitogenic activity of dermal fibroblasts. All patients referred to be highly satisfied and presented optimal clinical results after one month. Overall clinical improvement was maintained for 16 weeks. At the end of the study, the ultrasound examination revealed a cutaneous regenerative effect. No adverse events occurred.

CONCLUSIONS

This preliminary study suggests that autologous platelet gels have desirable mechanical and bioactive properties and allows moderate wrinkle reduction and efficient facial volume reposition with natural results.

Comprehensive Treatment of Noninfectious Uveitis Accompanied by Macular Edema with the Use of Autologous Platelet-Rich Plasma

Background. A common cause of visual impairment in patients with non-infectious uveitis is macular edema, developing in 38–84 % of cases. Plasma enriched with platelets is widely used in various branches of medicine, the effectiveness of its use in the treatment of non-infectious uveitis, accompanied by macular edema, has not been sufficiently investigated. Aim: To evaluate the effectiveness of autologous platelet-rich plasma in the complex treatment of non-infectious uveitis accompanied by macular edema.

Material and methods. The study was conducted on the basis of the academician S.N. Fyodorov Eye Microsurgery Federal State Institution in the period from 2016 to 2018, which included 123 people (176 eyes) from 18 to 50 years with non-infectious uveitis, accompanied by macular edema: 46 men, 77 women. Patients were divided into 2 groups. The main group consisted of patients receiving autologous platelet-rich plasma and anti-inflammatory treatment; the comparison group consisted of patients receiving anti-inflammatory treatment. The results of visual acuity, intraocular pressure, biomicroophthalmoscopy, optical coherence tomography of the macular zone, microperimetry, ultrasound examination on the side of the affected eye were evaluated. Statistical processing of the data was carried out in the program Statistica 10.

Results. Maintenance of autologous platelet-rich plasma contributes to a statistically significant improvement in visual acuity on the 10th day of treatment by 64.2 %, a decrease in the thickness of the retina in fovea by 36.3 % and an increase in retinal photosensitivity by 34.6 % compared to the group of patients receiving only anti-inflammatory treatment. Conclusions. The use of autologous platelet-rich plasma in the complex treatment of non-infectious uveitis allows to accelerate the natural mechanisms of tissue regeneration, contributing to the reduction of macular edema, and improve visual performance.

Do biomedical engineers dream of graphene sheets?

During the past few years, graphene has outstandingly emerged as a key nanomaterial for boosting the performance of commercial, industrial and scientific related technologies. The popularity of this novel nanomaterial in biomedical engineering is due to its excellent biological, electronic, optical and thermal properties that, as a whole, surpass the features of commonly used biomaterials and consequently open a wide range of applications so far within the reach of science fiction. In this minireview, the potential of graphene and its based materials in the expanding biomedical field is highlighted with focus on groundbreaking diagnostic, monitoring and therapeutic strategies. Some of the major challenges related to the synthesis and safety of graphene-based materials are also briefly discussed because of their critical importance in bringing this class of carbon materials closer to the clinic.

Platelet "first responders" in wound response, cancer, and metastasis

Platelets serve as "first responders" during normal wounding and homeostasis. Arising from bone marrow stem cell lineage megakaryocytes, anucleate platelets can influence inflammation and immune regulation. Biophysically, platelets are optimized due to size and discoid morphology to distribute near vessel walls, monitor vascular integrity, and initiate quick responses to vascular lesions. Adhesion receptors linked to a highly reactive filopodia-generating cytoskeleton maximizes their vascular surface contact allowing rapid response capabilities. Functionally, platelets normally initiate rapid clotting, vasoconstriction, inflammation, and wound biology that leads to sterilization, tissue repair, and resolution. Platelets also are among the first to sense, phagocytize, decorate, or react to pathogens in the circulation. These platelet first responder properties are commandeered during chronic inflammation, cancer progression, and metastasis. Leaky or inflammatory reaction blood vessel genesis during carcinogenesis provides opportunities for platelet invasion into tumors. Cancer is thought of as a non-healing or chronic wound that can be actively aided by platelet mitogenic properties to stimulate tumor growth. This growth ultimately outstrips circulatory support leads to angiogenesis and intravasation of tumor cells into the blood stream. Circulating tumor cells reengage additional platelets, which facilitates tumor cell adhesion, arrest and extravasation, and metastasis. This process, along with the hypercoagulable states associated with malignancy, is amplified by IL6 production in tumors that stimulate liver thrombopoietin production and elevates circulating platelet numbers by thrombopoiesis in the bone marrow. These complex interactions and the "first responder" role of platelets during diverse physiologic stresses provide a useful therapeutic target that deserves further exploration.