A novel personalized 3D injectable protein scaffold for regenerative medicine

Biochemical and biomechanical characterization of an autologous protein-based fibrin sealant for regenerative medicine

Accidental events or surgical procedures usually lead to tissue injury. Fibrin sealants have proven to optimize the healing process but have some drawbacks due to their allogeneic nature. Autologous fibrin sealants present several advantages. The aim of this study is to evaluate the performance of a new autologous fibrin sealant based on Endoret®PRGF® technology (E-sealant). One of the most widely used commercial fibrin sealants (Tisseel®) was included as comparative Control. E-sealant´s hematological and biological properties were characterized. The coagulation kinetics and the microstructure were compared. Their rheological profile and biomechanical behavior were also recorded. Finally, the swelling/shrinkage capacity and the enzymatic degradation of adhesives were determined. E-sealant presented a moderate platelet concentration and physiological levels of fibrinogen and thrombin. It clotted 30 s after activation. The microstructure of E-sealant showed a homogeneous fibrillar scaffold with numerous and scattered platelet aggregates. In contrast, Control presented absence of blood cells and amorphous protein deposits. Although in different order of magnitude, both adhesives had similar rheological profiles and viscoelasticity. Control showed a higher hardness but both adhesives presented a pseudoplastic hydrogel nature with a shear thinning behavior. Regarding their adhesiveness, E-sealant presented a higher tensile strength before cohesive failure but their elastic stretching capacity and maximum elongation was similar. While E-sealant presented a significant shrinkage process, Control showed a slight swelling over time. In addition, E-sealant presented a high enzymatic resorption rate, while Control showed to withstand the biodegradation process in a significant way. E-sealant presents optimal biochemical and biomechanical properties suitable for its use as a fibrin sealant with regenerative purposes.

Layer-by-Layer Analysis of In Vitro Skin Models

In vitro human skin models are evolving into versatile platforms for the study of skin biology and disorders. These models have many potential applications in the fields of drug testing and safety assessment, as well as cosmetic and new treatment development. The development of in vitro skin models that accurately mimic native human skin can reduce reliance on animal models and also allow for more precise, clinically relevant testing. Recent advances in biofabrication techniques and biomaterials have led to the creation of increasingly complex, multilayered skin models that incorporate important functional components of skin, such as the skin barrier, mechanical properties, pigmentation, vasculature, hair follicles, glands, and subcutaneous layer. This improved ability to recapitulate the functional aspects of native skin enhances the ability to model the behavior and response of native human skin, as the complex interplay of cell-to-cell and cell-to-material interactions are incorporated. In this review, we summarize the recent developments in in vitro skin models, with a focus on their applications, limitations, and future directions.

Platelet-Rich Plasma Gel Matrix (PRP-GM): Description of a New Technique

Several musculoskeletal conditions are triggered by inflammatory processes that occur along with imbalances between anabolic and catabolic events. Platelet-rich plasma (PRP) is an autologous product derived from peripheral blood with inherent immunomodulatory and anabolic properties. The clinical efficacy of PRP has been evaluated in several musculoskeletal conditions, including osteoarthritis, tendinopathy, and osteonecrosis. When used in combination with hyaluronic acid (HA), a common treatment alternative, the regenerative properties of PRP are significantly enhanced and may provide additional benefits in terms of clinical outcomes. Recently, a new PRP-derived product has been reported in the literature and is being referred to as "plasma gel". Plasma gels are obtained by polymerizing plasmatic proteins, which form solid thermal aggregates cross-linked with fibrin networks. Plasma gels are considered to be a rich source of growth factors and provide chemotactic, migratory, and proliferative properties. Additionally, clot formation and the associated fibrinolytic reactions play an additional role in tissue repair. There are only a few scientific articles focusing on plasma gels. Historically, they have been utilized in the fields of aesthetics and dentistry. Given that the combination of three products (PRP, HA, and plasma gel) could enhance tissue repair and wound healing, in this technical note, we propose a novel regenerative approach, named "PRP-HA cellular gel matrix" (PRP-GM), in which leukocyte-rich PRP (LR-PRP) is mixed with a plasma gel (obtained by heating the plasma up) and HA in one syringe using a three-way stopcock. The final product contains a fibrin-albumin network entangled with HA's polymers, in which the cells and biomolecules derived from PRP are attached and released gradually as fibrinolytic reactions and hyaluronic acid degradation occur. The presence of leukocytes, especially monocytes and macrophages, promotes tissue regeneration, as type 2 macrophages (M2) possess an anti-inflammatory feature. In addition, HA promotes the viscosuplementation of the joint and induces an anti-inflammatory response, resulting in pain relief. This unique combination of biological molecules may contribute to the optimization of regenerative protocols suitable for the treatment of degenerative musculoskeletal diseases.

A novel autologous dermal filler based on cultured fibroblasts and plasma gel for facial wrinkles: Long term results

Autologous cultured fibroblasts combined with plasma gel (Fibrogel^TM) can be used as an injectable autologous soft tissue filler. Herein, we report the assessment of the long-term clinical efficacy and safety of Fibrogel for facial wrinkles. Ten healthy adults were treated for facial wrinkles with Fibrogel, an innovative autologous filler. Patients underwent three treatment sessions at 1-month intervals for the correction of infraorbital, nasolabial, and marionette folds. In each session, 6-8 mL of Fibrogel filler containing 4 million fibroblasts/mL, was injected into the deep dermis or subdermal plane. Three evaluators independently assessed the efficacy at 3, 6 and 12 months after the last treatment, using the validated Global Esthetic Improvement Scale at two different times in a blinded manner. Infraorbital area and lower face were evaluated separately. All patients showed immediate improvement after the first injection at the infraorbital area and lower face. Follow-ups at 3, 6 and 12 months revealed that the improvement was persistent. Adverse reactions were mild and the treatment was well tolerated. Delivering autologous cultured fibroblasts embedded in an autologous plasma gel (Fibrogel) to the skin can provide immediate volume effect and long-term improvement. Therefore, Fibrogel can be considered as a promising novel autologous filler.

Autologous Biological Vitamin-C-added (ABC) Filler for Facial Volume Restoration

PURPOSE

Face rejuvenation procedures with injectable agents continue to gain popularity. Nowadays, a variety of commercial products are available as filler material. Ideal fillers should be inexpensive, easily obtainable, nontoxic, and biocompatible. The aim of this study is to report a clinical perspective for an appropriate, feasible, and inexpensive protocol of a stable, autologous biological filler for facial volume restoring without any commercial kits.

METHODS

Eight patients were investigated who underwent facial injection with ABC filler. Eleven ml of whole blood was placed in standard tubes containing anticoagulant and for each patient, 8 tubes were prepared. After the centrifugation at 1630 xg for 5 minutes, the upper plasma was taken, calcium was added and cooled. After the addition of vitamin C, the syringes were incubated at 85 °C for 10 minutes. The autologous biological material obtained was used as filling material. For comparison, FACE-Q satisfaction questionnaires were used before and after the procedure.

RESULTS

All patients were followed up for a minimum of 4 months. No major complications were recorded. The patient-reported FACE-Q satisfaction and FACE-Q quality of life pre- and post-procedure results showed statistically significant improvement (p  <  0.05). Overall satisfaction with the outcome was 89.12 ± 16.73 (range 55-100).

CONCLUSIONS

ABC filler can be seen as a reliable, inexpensive, and easily obtainable material to restore facial volume with increased patient satisfaction and quality of life scores. We believe that our study will be encouraging to the application of autologous biological fillers for further clinical and scientific studies.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

3D printable self-healing hyaluronic acid/chitosan polycomplex hydrogels with drug release capability

Multifunctional printable biomaterials are at the base of advanced biomedical applications. Chitosan (CHI) and hyaluronic acid (HA) allow the development of polycomplex hydrogels with tailorable properties, including self-healing and controlled drug release. This work correlates and optimizes the mucoadhesive, swelling, biodegradation, mechanical and rheological properties of HA/CHI polycomplex hydrogels with synthesis parameters such as polysaccharide content and complexation time, according to the interaction forces established between both polyelectrolytes. Related to these dynamic forces, the self-healing ability of the hydrogels was investigated together with the potential of the HA/CHI polycomplex hydrogels for 3D printing. Finally, their capability to modulate and promote controlled release of a variety of drugs (anionic and anti-inflammatory sodium diclofenac and the neutral antibiotic rifampicin) was demonstrated. Thus, the reported tunable properties, self-repair ability, printability and drug release properties, demonstrate the suitability of HA/CHI hydrogels for advanced biomedical applications.

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.

Design and applications of protein delivery systems in nanomedicine and tissue engineering

Proteins are biological macromolecules involved in a wide range of biological functions, which makes them very appealing as therapeutics agents. Indeed, compared to small molecule drugs, their endogenous nature ensures their biocompatibility and biodegradability, they can be used in a large range of applications and present a higher specificity and activity. However, they suffer from unfolding, enzymatic degradation, short half-life and poor membrane permeability. To overcome such drawbacks, the development of protein delivery systems to protect, carry and deliver them in a controlled way have emerged importantly these last years. In this review, the formulation of a wide panel of protein delivery systems either in the form of polymer or inorganic nanoengineered colloids and scaffolds are presented and the protein loading and release mechanisms are addressed. A section is also dedicated to the detection of proteins and the characterization methods of their release. Then, the main protein delivery systems developed these last three years for anticancer, tissue engineering or diabetes applications are presented, as well as the major in vivo models used to test them. The last part of this review aims at presenting the perspectives of the field such as the use of protein-rich material or the sequestration of proteins. This part will also deal with less common applications and gene therapy as an indirect method to deliver protein.

Combined therapy with Endoret-Gel and plasma rich in growth factors vs Endoret-Gel alone in the management of facial rejuvenation: A comparative study

BACKGROUND

Skin suffers progressive decrement. An endogenous regenerative technology has been developed that has the versatility to provide an autologous injectable gel (Endoret-Gel) or a liquid plasma rich in growth factors (PRGF) based on the patient´s own platelet-rich plasma.

AIMS

To compare the efficacy of the combined therapy with Endoret-Gel and PRGF versus Endoret-Gel alone in the management of facial rejuvenation.

METHODS

Twenty clinically diagnosed patients with aged skin received either Endoret-Gel monotherapy or Endoret-Gel + PRGF combined therapy. Patients underwent three sessions at one-month intervals and were clinically assessed for six months. Corneometry, sebumetry, and high-resolution topographic analysis were carried out. Patient self-assessment questionnaires and clinical improvement scores were also performed.

RESULTS

The combined therapy showed to promote a higher hydration index. These results were also significant for spot improvement at three months, while conversely, monotherapy with Endoret-Gel demonstrated higher UV spot improvement. A significant decrease of sebum production and wrinkle development was observed for both treatment groups. Red areas also improved in a similar way at the end of the follow-up period. After Endoret-Gel or Endoret-Gel + PRGF therapy, 30% and 70% of patients referred to be very satisfied, respectively. Accordingly, 40% and 80% showed a "very improved" esthetic performance. None of the patients reported a negative change and no adverse events were recorded.

CONCLUSION

Both Endoret-Gel monotherapy and the combined treatment with PRGF were shown to promote facial rejuvenation and to palliate the age-related cutaneous atrophy. The combined therapy may exert a synergistic effect that addresses both skin quality improvement and soft tissue restoration in a shorter period.

Long-term stability of a novel platelet-rich plasma-based topical serum for cutaneous applications

BACKGROUND

Skin alterations are usually related to chronic diseases that demand sustained and long-term dosages; hence, it is pivotal that the stability of treatments is preserved. A novel storable and endogenous topical serum (ES) based on the patient's own blood has been recently developed.

AIMS

To investigate the long-term stability of the formulation and to provide preliminary data of its biologic potential.

METHODS

Samples from six donors were obtained and either used as fresh samples or cold-stored for 6 months. Physicochemical, rheological, and biological stability of the formulation was determined.

RESULTS

Endogenous topical serum maintained unaltered its organoleptic properties, viscosity, pH, spreadability index, and sterility. The growth factor content including TGFβ-I, EGF, PDGF-AB, HGF, and Ang-I showed no decrease. In contrast, ES showed lower levels of IGF-I once stored. Dermal fibroblasts showed no change in their proliferative activity.

CONCLUSION

Endogenous topical serum showed to maintain its physicochemical and biological properties after six months of storage. ES might reduce the frequency of blood extractions and would enable patients with chronic disorders to maintain a daily use of the product in a minimally invasive way.

Plasma rich in growth factor gel as an autologous filler for facial volume restoration

BACKGROUND

Skin aging is characterized by moderate to severe wrinkles, laxity, roughness, and volume loss as a result of cutaneous atrophy and connective tissue degradation. Plasma rich in growth factor gel (PRGF-gel) is a novel formulation obtained from the patient's own blood that has demonstrated optimal biomechanical and bioactive properties for soft tissue restoration.

OBJECTIVES

Following a retrospective design, the clinical safety and efficacy of PRGF-gel for facial volume restoration and skin rejuvenation were evaluated.

METHODS

Twenty women clinically diagnosed for aged skin symptoms were treated with PRGF-gel. Participants received an individualized regimen depending on their therapeutic needs. At the end of the follow-up periods, clinical performance analysis was evaluated by standardized macrophotographs along with clinical and patient surveys based on Likert's scales.

RESULTS

Based on their initial expectations, patients referred to be highly satisfied after PRGF-gel treatment in terms of fine line amelioration, wrinkle reduction, and sagging improvement (overall satisfaction of 8/10). Pre/post-photograph clinical evaluation showed an improvement of 2.5/3 and patients presented a noticeable face rejuvenation due to the soft tissue augmentation effect which was translated into surface texture softening and tone recovery.

CONCLUSIONS

Although additional randomized clinical trials should be carried out, this study provides preliminary data supporting the use of PRGF-gel for facial volume restoration.

In vitro characterization and clinical use of platelet-rich plasma-derived Endoret-Gel as an autologous treatment for atrophic scars

BACKGROUND

Normal healing process becomes severely dysregulated in pathophysiological conditions such as inflammation, infection or underlaying diseases. These scenarios hamper the standard healing pattern and dermal fibrotic tissue develops.

OBJECTIVE

In the present study a novel three-dimensional formulation (Endoret-Gel) based on plasma rich in growth factors technology (Endoret-PRGF) has been assessed for atrophic scar management.

MATERIALS AND METHODS

Microstructure analysis, growth factor content, and projection capacity of both formulations (Endoret-Gel and Endoret-PRGF) was assessed. Additionally, a clinical evaluation of Endoret-Gel treatment was also performed in a case of an extense atrophic scar.

RESULTS

Endoret-Gel presented high molecular weight plasmatic proteins that formed solid thermal aggregates enclosed by a stable fibrin network. This formulation has a higher cutaneous projection capacity compared with Endoret-PRGF. Both formulations presented a high load of bioactive proteins such as EGF, PDGF-AB, and IGF-I being higher in liquid Endoret-PRGF. Clinical results evidenced that infiltrations of Endoret-Gel derived in an early volumetric disposal that was maintained for several months. The treatment provided and immediate soft tissue augmentation and scar amelioration effect that was translated into a noticeable clinical improvement of the injury. No side effects or adverse events were reported during ten-month follow-up period.

CONCLUSION

These preliminary findings suggest that Endoret-Gel may act not only as a temporary volumizer but also as soft tissue stimulator that might be used as a monotherapy for scar management.

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.

A novel protein-based autologous topical serum for skin regeneration

BACKGROUND

As skin ages, a functional decrement occurs. To avoid future vulnerability to dermatologic diseases, an optimal cutaneous regeneration is mandatory. Biological therapies based on blood-derived autologous proteins are gaining attention of scientists and dermatologists.

OBJECTIVES

A novel 100% autologous topical serum has been developed using plasma rich in growth factors technology. The physicochemical characterization and the biologic potential of the novel formulation have been studied.

METHODS

Rheological and mechanical properties and the biological capacity of the formulation were characterized. Human dermal fibroblast culture and 3D organotypic skin explants were used as in vitro and ex vivo cutaneous models, respectively.

RESULTS

The autologous topical serum presented an optimal spreadability index and appropriate shear thinning behavior that allowed an easy handling and rapid integration within the cutaneous tissue. The formulation has a high growth factor load with the ability to progressively penetrate into the dermal/epidermal layers of the skin. It is biocompatible and promotes cell proliferation and chemotactic activity. The autologous topical serum promotes the biosynthetic activity of cells by the stimulation of collagen and hyaluronic acid expression.

CONCLUSIONS

These findings present an in situ and easy to prepare autologous topical serum based on the patient's own blood with physicochemical and bioactive properties that may be used for skin regeneration purposes.

Autologous plasma rich in growth factors technology for isolation and ex vivo expansion of human dental pulp stem cells for clinical translation

AIM

This study investigated the use of the autologous technology of plasma rich in growth factors (PRGF) as a human-based substitute to fetal bovine serum (FBS) in the culture of human dental pulp stem cells.

MATERIALS & METHODS

Stem cell characterization was performed. Analysis of isolation, proliferation, migration, trilineage differentiation, senescence and cryopreservation were compared between FBS and PRGF.

RESULTS

Human dental pulp stem cell cultures isolated and maintained with PRGF showed a significantly higher number of cells per explant than FBS cultures. Cell proliferation, migration, osteogenic mineralization and adipogenic differentiation were found to be significantly higher in PRGF than FBS.

CONCLUSION

The autologous PRGF technology could be a suitable and safer substitute for FBS as a culture medium supplement for clinical translation of cell therapy.