Platelet-rich plasma and/or sildenafil topical applications accelerate and better repair wound healing in rats through regulation of proinflammatory cytokines and collagen/TGF-β1 pathway

Blood Plasma, Fibrinogen or Fibrin Biomaterial for the Manufacturing of Skin Tissue-Engineered Products and Other Dermatological Treatments: A Systematic Review

The use of blood plasma, fibrinogen or fibrin, a natural biomaterial, has been widely studied for the development of different skin tissue-engineered products and other dermatological treatments. This systematic review reports the preclinical and clinical studies which use it alone or combined with other biomaterials and/or cells for the treatment of several dermatological conditions. Following the PRISMA 2020 Guidelines, 147 preclinical studies have revealed that the use of this biomaterial as a wound dressing or as a monolayer (one cell type) skin substitute are the preferred strategies, mainly for the treatment of excisional or surgical wounds. Moreover, blood plasma is mainly used alone although its combination with other biomaterials such as agarose, polyethylene glycol or collagen has also been reported to increase its wound healing potential. However, most of the 17 clinical reviewed evaluated its use for the treatment of severely burned patients as a wound dressing or bilayer (two cell types) skin substitute. Although the number of preclinical studies evaluating the use of blood plasma as a dermatological treatment has increased during the last fifteen years, this has not been correlated with a wide variety of clinical studies. Its safety and wound healing potential have been proved; however, the lack of a standard model and the presence of several approaches have meant that its translation to a clinical environment is still limited. A higher number of clinical studies should be carried out in the coming years to set a standard wound healing strategy for each dermatological disease.

Investigating the Antibacterial, Antioxidant, and Anti-Inflammatory Properties of a Lycopene Selenium Nano-Formulation: An In Vitro and In Vivo Study

BACKGROUND

The potent antioxidant lycopene has attracted a large amount of research attention given its potential health benefits. We aimed to assess the antimicrobial, anti-inflammatory, and antioxidant properties of lycopene (Lyc), selenium nanoparticles (Se-NPs), and lycopene selenium nanoparticles (Lyc-Se-NPs).

METHODS

FTIR, polydispersity index, and zeta potential evaluations provided a complete characterization of the synthesized Lyc-Se-NPs. The broth dilution method and a crystal violet microtiter plate assay were employed to assess the antibacterial and antibiofilm activity, respectively. The rat wound infection model was performed to study the anti-inflammatory effect.

FINDINGS

The Lyc-Se-NPs had a zeta potential range of -16.93 to -31.04 mV and a mean particle size of 126.6 ± 3.12 nm. All peaks' percentage transmittance decreased, according to the FTIR analysis of the Lyc-Se-NPs, with the exception of one peak at 2924.22 cm-1, which is suggestive of C-H stretching. The mean scavenging concentrations for Lyc-Se-NPs in the DPPH and ABTS radical scavenging experiments were 3.85 ± 0.65 and 4.26 ± 0.7 µg/mL, respectively. For S. aureus, the Lyc-Se-NPs' MIC values varied from 64 to 1024 µg/mL. CLSM verified that S. aureus treated with sub-MICs of Lyc-Se-NPs showed a significant reduction in biofilm formation. Furthermore, the group treated with 50 mg of Lyc-Se-NPs showed the quickest rate of wound healing. They demonstrated a notable elevation of the HO-1 content in skin tissues, together with the greatest downregulation of TNF-α, IL-1β, and COX-2.

CONCLUSIONS

The distinguishing features of Lyc-Se-NPs reveal that this unique compound is a promising antibacterial, antioxidant, and anti-inflammatory agent.

Exploring the Multifaceted Potential of Sildenafil in Medicine

Phosphodiesterase type 5 (PDE5) is pivotal in cellular signalling, regulating cyclic guanosine monophosphate (cGMP) levels crucial for smooth muscle relaxation and vasodilation. By targeting cGMP for degradation, PDE5 inhibits sustained vasodilation. PDE5 operates in diverse anatomical regions, with its upregulation linked to various pathologies, including cancer and neurodegenerative diseases. Sildenafil, a selective PDE5 inhibitor, is prescribed for erectile dysfunction and pulmonary arterial hypertension. However, considering the extensive roles of PDE5, sildenafil might be useful in other pathologies. This review aims to comprehensively explore sildenafil's therapeutic potential across medicine, addressing a gap in the current literature. Recognising sildenafil's broader potential may unveil new treatment avenues, optimising existing approaches and broadening its clinical application.

An extracellular matrix-inspired self-healing composite hydrogel for enhanced platelet-rich plasma-mediated chronic diabetic wound treatment

Diabetes is generally accompanied by difficult-to-heal wounds, which often lead to permanent disability and even death of patients. Because of the abundance of a variety of growth factors, platelet rich plasma (PRP) has been proven to have great clinical potential for diabetic wound treatment. However, how to suppress the explosive release of its active components while realizing adaptability to different wounds remains important for PRP therapy. Here, an injectable, self-healing, and non-specific tissue-adhesive hydrogel formed by oxidized chondroitin sulfate and carboxymethyl chitosan was designed as an encapsulation and delivery platform for PRP. With a dynamic cross-linking structural design, the hydrogel can meet the clinical demands of irregular wounds with controllable gelation and viscoelasticity. Inhibition of PRP enzymolysis as well as sustained release of its growth factors is realized with the hydrogel, enhancing cell proliferation and migration in vitro. Notably, greatly accelerated healing of full thickness wounds of diabetic skins is enabled by promoting the formation of granulation tissues, collagen deposition and angiogenesis as well as reducing inflammation in vivo. This self-healing and extracellular matrix-mimicking hydrogel provides powerful assistance to PRP therapy, enabling its promising applications for the repair and regeneration of diabetic wounds.

The contribution of immunohistochemistry to the development of hydrogels for skin repair and regeneration

Hydrogels based on various polymeric materials have been successfully developed in recent years for a variety of skin applications. Several studies have shown that hydrogels with regenerative, antibacterial, and antiinflammatory properties can provide faster and better healing outcomes, particularly in chronic diseases where the normal physiological healing process is significantly hampered. Various experimental tests are typically performed to assess these materials' ability to promote angiogenesis, re-epithelialization, and the production and maturation of new extracellular matrix. Immunohistochemistry is important in this context because it allows for the visualization of in situ target tissue factors involved in the various stages of wound healing using antibodies labelled with specific markers detectable with different microscopy techniques. This review provides an overview of the various immunohistochemical techniques that have been used in recent years to investigate the efficacy of various types of hydrogels in assisting skin healing processes. The large number of scientific articles published demonstrates immunohistochemistry's significant contribution to the development of engineered biomaterials suitable for treating skin injuries.

Emerging Delivery Strategies of Platelet-Rich Plasma with Hydrogels for Wound Healing

Platelet-rich plasma (PRP), a platelet-rich plasma concentrate obtained from whole blood, has been widely used to treat wounds due to its high contents of growth factors that can not only play a role in the hemostasis, repair, and anti-infection of wounds but also promote cell proliferation, maturation, and angiogenesis. However, after PRP activation, its clinical effect was limited because of burst and uncontrolled release of growth factors and poor mechanical properties of PRP gels. In recent years, increasing attention has been moved to the loading and sustained release of growth factors in PRP by polymeric carriers. Hydrogels, as an interesting carrier, enable controlled delivery of growth factors by structural designs. Moreover, using hydrogels to encapsulate PRP is favorable to controlling the mechanical properties and water maintenance of PRP gels, which can provide a stable and moist wound repair environment to promote coordinated operations of skin tissue cells and cytokines as well as wound healing. In this review, the state of the art of hydrogels that have been used to load PRP for wound treatments is introduced, and further prospects in the research area are proposed.

Sildenafil-Induced Revascularization of Rat Hindlimb Involves Arteriogenesis through PI3K/AKT and eNOS Activation

Hypoxia and inflammation play a major role in revascularization following ischemia. Sildenafil inhibits phosphodiesterase-5, increases intracellular cGMP and induces revascularization through a pathway which remains incompletely understood. Thus, we investigated the effect of sildenafil on post-ischemic revascularization. The left femoral artery was ligated in control and sildenafil-treated (25 mg/kg per day) rats. Vascular density was evaluated and expressed as the left/right leg (L/R) ratio. In control rats, L/R ratio was 33 ± 2% and 54 ± 9%, at 7- and 21-days post-ligation, respectively, and was significantly increased in sildenafil-treated rats to 47 ± 4% and 128 ± 11%, respectively. A neutralizing anti-VEGF antibody significantly decreased vascular density (by 0.48-fold) in control without effect in sildenafil-treated animals. Blood flow and arteriolar density followed the same pattern. In the ischemic leg, HIF-1α and VEGF expression levels increased in control, but not in sildenafil–treated rats, suggesting that sildenafil did not induce angiogenesis. PI3-kinase, Akt and eNOS increased after 7 days, with down-regulation after 21 days. Sildenafil induced outward remodeling or arteriogenesis in mesenteric resistance arteries in association with eNOS protein activation. We conclude that sildenafil treatment increased tissue blood flow and arteriogenesis independently of VEGF, but in association with PI3-kinase, Akt and eNOS activation.