Activation of adenosine A2A receptors restores the altered cell-cycle machinery during impaired wound healing in genetically diabetic mice

Versatile and Marvelous Potentials of Polydeoxyribonucleotide for Tissue Engineering and Regeneration

Over the past decade, substantial focus has been placed on polydeoxyribonucleotide (PDRN) due to its promising pharmacological properties, making it a valuable candidate for tissue engineering applications. Accordingly, this paper aims to review and summarize the latest experimental research on PDRN in the context of tissue engineering and regeneration. The unique biochemical mechanisms of PDRN to promote cellular behavior and regeneration are summarized. We categorize commonly utilized PDRN-based tissue engineering fields as neuromuscular tissues, diabetic wound or skin, and bone regeneration. At the same time, we explore scaffold strategies for integrating PDRN into bioceramics, polymers, and cell/tissue-derived materials, along with its combination with photo/electromodulation techniques. Furthermore, we discuss potential opportunities and challenges in translating PDRN-based approaches into clinical practice. We expect future interdisciplinary research and clinical trials to evaluate the long-term efficacy and safety of PDRN while emphasizing standardization and quality control to ensure its consistency and effectiveness in regenerative applications.

Caprine dermal scaffolds for repair of full-thickness skin wounds in rabbits

Biological scaffolds prepared after decellularization are used for the restoration of damaged tissues. A number of chemicals are used for bioscaffold preparation, and some of them damage their composition and architecture. Herein, we investigated the Sapindus mukorossi fruit pericarp extract (SPE) (5%) for decellularization of the caprine dermis. The dermal samples were processed in 5% SPE over magnetic stirrer for 96h at room temperature. The decellularization efficiency of SPE was analyzed by histological examination, DAPI staining, scanning electron microscopy (SEM), quantification of DNA hydroxyproline and hemocompatibility determination. Further, these acellular caprine dermal scaffolds were transplanted on full thickness skin wounds of group III New Zealand white rabbits. The wounds were left open in group I (Sham) and reconstructed by autograft in group II (n = 6 in each group). Continuous agitation of native caprine dermal tissues in 5% SPE for 96 hours leads to complete decellularization without affecting the extracellular matrix architecture. Microscopic observation of decellularized samples did not show any nuclei. DNA quantity was reduced (p < .05) in decellularized samples and scaffolds were found to be hemocompatible. Complete healing was observed on day 28 in groups II and III. No significant difference was noted in IgG in all the groups. Quantitative assessment of MDA showed a significant increase in groups I and II. Our results suggested that the 5% SPE solution effectively decellularized the native caprine dermis and the scaffolds were well tolerated by the animals.

In Vitro Evaluation and Clinical Effects of a Regenerative Complex with Non-Cross-Linked Hyaluronic Acid and a High-Molecular-Weight Polynucleotide for Periorbital Treatment

Skin aging is a complex and multifactorial process influenced by both intrinsic and extrinsic factors. The periorbital area of the face is particularly susceptible to premature aging signs due to its delicate skin structure, and is a major concern for many individuals. While hyaluronic acid (HA)-based dermal filler products are commonly used for periorbital rejuvenation, novel approaches to effectively locally address the visible signs of aging are available. This study aimed to investigate Innovyal Regenerative Action (IRA), an injectable polynucleotide-HA (PN-HA) regenerative complex designed for periocular prejuvenation. Firstly, PN-HA was compared to other commercially available HA-based dermbooster products (Profhilo®, Suisselle Cellbooster® Glow, and NCTF® 135 HA) in terms of rheological properties, in vitro antioxidant capacity, and total collagen production stimulation in human fibroblasts. Secondly, the clinical effects of the IRA PN-HA complex were evaluated in two case reports (monotherapy for periorbital prejuvenation). It was shown that the PN-HA complex outperformed its comparators in terms of relative rheological behavior (biophysical attributes normalized to polymer contents), intrinsic antioxidant activity (CUPRAC, FRAP, and ORAC assays), as well as total collagen level induction (72-h in vitro dermal fibroblast induction model). Generally, the results of this study provided mechanistic and preliminary clinical insights into the potential benefits of the IRA PN-HA complex for periocular cutaneous treatment. Overall, it was underscored that combining the structural support and regenerative properties of PN with the hydrating and volumizing effects of HA bares tangible potential for multifactorial skin quality enhancement and for periocular prejuvenation in particular.

Effects of Chlorella protothecoides-derived polydeoxyribonucleotides on skin regeneration and wound healing

The skin acts as a crucial barrier and, upon injury, initiates complex wound-healing processes involving various cell types. Polydeoxyribonucleotides (PDRNs) are well-known for their efficacy in enhancing skin regeneration and wound healing. This study sought to investigate the effectiveness of PDRNs derived from Chlorella protothecoides, a sustainable and scalable microalgal source, in promoting skin regeneration and wound healing. Keratinocytes and fibroblasts were used for assessing the impact of PDRNs on cell proliferation, migration, collagen synthesis, and angiogenesis. Gene expression and associated signaling pathways were also examined using RT-qPCR and Western blot analyses. Our findings demonstrated that PDRNs significantly enhanced the proliferation and migration of skin cells, upregulated growth arrest specific 6 (GAS6) and hepatocyte growth factor (HGF) expression, and increased collagen synthesis by modulating collagen type I alpha 1 (COLIA1) expression. Additionally, PDRNs enhanced angiogenesis by promoting vascular endothelial growth factor (VEGF) expression and activation of ERK, AKT, β-catenin and STAT3 pathways via an adenosine A2A receptor (A2AR)-dependent mechanism. These findings suggest that microalgal-derived PDRNs have significant potential as sustainable and effective agents for clinical and cosmetic applications aimed at improving skin health and wound healing.

Traditional uses, botany, phytochemistry, pharmacology and applications of Labisia pumila: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Labisia pumila (Blume) Fern.-Vill, also known as Kacip Fatimah, is a traditional medicinal herb common throughout Southeast Asia. It is primarily used to facilitate childbirth and postpartum recovery in women. Additionally, it can also be used to treat dysentery, rheumatism, gonorrhea, and as an anti-flatulent.

AIM OF THIS REVIEW

This article aims to provide a comprehensive review of the traditional uses, botany, cultivation, phytochemistry, pharmacological effects, practical applications, and potential uses of L. pumila (LP). Furthermore, we also explore the safety of this plant and its potential prospects for application.

MATERIALS AND METHODS

The keywords "Labisia pumila," "Kacip Fatimah," and "Marantodes pumilum" were used to collect relevant information through electronic searches (including Elsevier, PubMed, Google Scholar, Baidu Scholar, CNKI, ScienceDirect, and Web of Science).

RESULTS

This review summarizes 102 chemical components from different parts of the plant, including flavonoids, phenolic acids, saponins, and other chemical components. In addition, we also address the associated cultivation conditions, traditional uses, pharmacological effects and toxicity. A large number of reports indicate that LP has various pharmacological effects such as antioxidant, phytoestrogenic, anti-inflammtory, antimicrobial, anti-osteoporosis and anti-obesity properties. These results provide valuable references for future research on LP. In addition, LP is also a potential medicinal and edible plant, and is currently sold on the market as a dietary supplement.

CONCLUSIONS

LP is a renowned traditional ethnic medicine with numerous pharmacological activities attributed to its bioactive components. Therefore, isolation and identification of the chemical components in LP can be a focus of our future research. Current studies have focused only on the effects of LP on estrogen deficiency-related diseases in women and bone diseases. There is no scientific evidence for other traditional uses. Therefore, it is important to further explore its pharmacological activities and fill the research gaps related to other traditional uses. Furthermore, research on its safety should be expanded to prepare clinical applications.

First Report on Microbial-Derived Polydeoxyribonucleotide: A Sustainable and Enhanced Alternative to Salmon-Based Polydeoxyribonucleotide

Polydeoxyribonucleotide (PDRN) has emerged as a potent bioactive compound with proven efficacy in wound healing, tissue regeneration, and anti-inflammatory applications and is predominantly derived from salmonid gonads. However, this study presents a groundbreaking advancement by successfully extracting and characterizing PDRN from microbial sources, specifically Lactobacillus rhamnosus, marking the first report to utilize microbial-, biome-, or Lactobacillus-derived PDRN (L-PDRN). The findings demonstrate the enhanced biological properties of L-PDRN over traditional salmon-derived PDRN across several assays. L-PDRN exhibited superior antioxidant activity, with significantly higher SOD-like and DPPH radical scavenging activities compared to PDRN, particularly at higher concentrations. In wound-healing assays, L-PDRN demonstrated superior efficacy in promoting cell migration and wound closure, even under inflammatory conditions induced by tumor necrosis factor (TNF-α). Additionally, L-PDRN demonstrated the potential for enhanced immunostimulatory effects under non-inflammatory conditions while maintaining anti-inflammatory properties under lipopolysaccharide (LPS) stimulation. Electrophoretic analysis revealed that L-PDRN consists of smaller DNA fragments (under 100 bp) compared to salmon-derived PDRN (200-800 bp), suggesting greater bioavailability and skin absorption. Mechanistic studies confirmed that L-PDRN activates the focal adhesion kinase (FAK) and protein kinase B (AKT) signaling pathway through the A2A receptor, similar to PDRN, while also engaging alternative pathways for p38 and ERK phosphorylation, highlighting its signaling versatility. This study underscores the potential of L-PDRN as a multifunctional and sustainable alternative to salmon-derived PDRN, offering enhanced bioactivity, scalability, and environmental benefits. The novel approach of utilizing microbial-derived PDRN opens new avenues for therapeutic applications in oxidative stress management, tissue regeneration, and immune modulation, paving the way for a paradigm shift in PDRN sourcing and functionality.

An agonist of the adenosine A2A receptor, CGS21680, promotes corneal epithelial wound healing via the YAP signalling pathway

BACKGROUND AND PURPOSE

The adenosine A2A receptor (A2AR) is involved in various physiological and pathological processes in the eye; however, the role of the A2AR signalling in corneal epithelial wound healing is not known. Here, the expression, therapeutic effects and signalling mechanism of A2AR in corneal epithelial wound healing were investigated using the A2AR agonist CGS21680.

EXPERIMENTAL APPROACH

A2AR localization and expression during wound healing in the murine cornea were determined by immunofluorescence staining, quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting. The effect of CGS21680 on corneal epithelial wound healing in the lesioned corneal and cultured human corneal epithelial cells (hCECs) by modulating cellular proliferation and migration was critically evaluated. The role of Hippo-YAP signalling in mediating the CGS21680 effect on wound healing by pharmacological inhibition of YAP signalling was explored.

KEY RESULTS

A2AR expression was up-regulated after corneal epithelial injury. Topical administration of CGS21680 dose-dependently promoted corneal epithelial wound healing in the injured corneal epithelium by promoting cellular proliferation. Furthermore, CGS21680 accelerated the cellular proliferation and migration of hCECs in vitro. A2AR activation promoted early up-regulation and later down-regulation of YAP signalling molecules, and pharmacological inhibition of YAP signalling reverted CGS21680-mediated wound healing effect in vivo and in vitro.

CONCLUSION AND IMPLICATIONS

A2AR activation promotes wound healing by enhancing cellular proliferation and migration through the YAP signalling pathway. A2ARs play an important role in the maintenance of corneal epithelium integrity and may represent a novel therapeutic target for facilitating corneal epithelial wound healing.

Effect of polydeoxyribonucleotide and polynucleotide on rotator cuff healing and fatty infiltration in a diabetic rat model

Failure rate after chronic rotator cuff repair is considerably high. Moreover, diabetes mellitus is known as a compromising factor of rotator cuff tear. The effect of Polydeoxyribonucleotide (PDRN) and polynucleotide (PN) on tendon healing and fatty infiltration is unclear as tissue regeneration activator in diabetic state. Therefore, a diabetic rat model with chronic rotator cuff tear was made for mechanical, histologic and blood tests. In the animal study using a diabetic rat cuff repair model, the administration of PDRN and PN increased the load to failure of repaired cuffs and improved tendon healing and decreased fatty infiltration. Also, the plasma levels of vascular endothelial growth factor and fibroblast growth factor were elevated in PDRN and PN administrated groups. We concluded that PDRN and PN appear to boost tendon recovery and reduce the presence of fatty infiltration following cuff repair in diabetic state. Also, PN showed a later onset and a longer duration than PDRN associated with the mean plasma growth factors.

Analysis of Skin Regeneration and Barrier-Improvement Efficacy of Polydeoxyribonucleotide Isolated from Panax Ginseng (C.A. Mey.) Adventitious Root

Polydeoxyribonucleotide (PDRN) has the ability to regenerate skin cells and improve the skin barrier and wound healing. This study investigated the possibility of replacing animal-derived PDRN with plant-derived PDRN. To test this, the adventitious roots of Korean ginseng (Panax ginseng C.A. Meyer), which is commonly used to treat various diseases, were suspension-cultivated through tissue culture; subsequently, PDRN was purified using microfluidization, an ultra-high-pressure physical grinding method. The results showed that purified Panax PDRN was effective in healing skin wounds and enhancing the skin barrier. Panax PDRN promoted the proliferation of keratinocytes and fibroblasts by increasing the expression of fibronectin, filaggrin, Ki-67, Bcl-2, inhibin beta A, and Cyclin D1. It also acted as an agonist of the adenosine A2A receptor and induced the phosphorylation of focal adhesion kinase, adenosine triphosphate-dependent tyrosine kinase, and mitogen-activated protein kinase. This activated signal transduction, thereby regenerating skin cells and strengthening the barrier. These results were not only observed in skin cells but also in an artificial skin model (KeraSkinTM). The use of plant-derived PDRN instead of animal-derived PDRN can promote animal welfare and environmental sustainability. Furthermore, Panax PDRN can potentially be a new plant-derived PDRN (PhytoPDRN) that may be utilized in the treatment of various skin diseases.

Efficacy of Polydeoxyribonucleotide in Promoting the Healing of Diabetic Wounds in a Murine Model of Streptozotocin-Induced Diabetes: A Pilot Experiment

We assessed the efficacy of polydeoxyribonucleotide (PDRN) in accelerating the healing of diabetic wounds in a murine model of streptozotocin (STZ)-induced diabetes. After the creation of diabetic wounds, the mice of the PDRN SC, PDRN IP and PBS groups received a subcutaneous, an intra-peritoneal injection of PDRN and a subcutaneous injection of PBS, respectively. After euthanasia, time-dependent changes in the wound diameter and histologic scores were measured and vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1) and collagen types I and III were assessed for their expression levels. The PDRN SC and the PDRN IP groups showed a significantly smaller diameter of diabetic wounds, significantly higher histologic scores, a significantly greater expression of VEGF, a significantly lower expression of TGF-β1 and a significantly greater expression of collagen types I and III as compared with the PBS group (p < 0.05 or 0.0001). In conclusion, PDRN might be effective in promoting the healing of diabetic wounds in a murine model of STZ-induced diabetes.

Adipose mesenchymal stem cell sheets-derived extracellular vesicles-microRNA-10b promote skin wound healing by elevating expression of CDK6

Application of adipose-derived mesenchymal stromal cells (AMSCs)-derived extracellular vesicles (EVs) in skin wound healing has been documented. In this study, we investigated the therapeutic potential of AMSCs-derived EVs in skin wound healing through delivery of microRNA-10b (miR-10b). HaCaT cells were treated with H₂O₂ to establish the skin wound cell models. Next, the binding affinity between miR-194, PEA15, and CDK6 was identified. Additionally, EVs were isolated from the culture medium of AMSC sheets, followed by incubation with H₂O₂-treated HaCaT cells to detect cell proliferation, migration, and apoptosis using gain- or loss-of-function experiments. Lastly, the mice skin wound models were also established to assess skin wound healing ability. miR-10b was down-regulated in the skin trauma models and enriched in the EVs of AMSC sheets. Moreover, miR-10b derived from EVs targeted PEA15 to promote CDK6 expression, thereby stimulating the proliferation and migration of H₂O₂-damaged HaCaT cells but inhibiting apoptosis. In vivo experiments further ascertained the therapeutic functionality of AMSC sheets-derived EVs-miR-10b. In summary, AMSC sheets-derived EVs carrying miR-10b promoted CDK6 expression to intensify skin wound healing by regulating PEA15.

Role of Oxidative Stress in Varicocele

According to the official statistics of the World Health Organization, at least 48 million couples and 186 million people suffer from infertility. Varicocele has been recognized as the leading cause of male infertility and can affect spermatogenesis and cause testicular and epididymal disorders through multiple diverse pathophysiological processes. Reactive oxygen species (ROS) produced by oxidative stress have been reconciled as an important pathogenic factor throughout the course of varicocele. Testis respond to heat stress, hypoxia, and inflammation at the cost of producing excessive ROS. High levels of ROS can lead to infertility not only through lipid peroxidation or DNA damage, but also by inactivating enzymes and proteins in spermatogenesis. This review studies the oxidative stress and its role in the pathophysiology and molecular biology of varicocele in the context of a decline in fertility.

Topical Polydeoxyribonucleotide Loaded in Hydrogel Formulation for Wound Healing in Diabetic Rats

Patients with diabetes mellitus experience delayed wound healing because of the uncontrolled glucose level leads to impaired cell proliferative function, poor circulation, decreased production and repair of new blood vessels. Polydeoxyribonucleotide (PDRN) is used in wound healing as a substance that stimulates tissue repair. A hydrogel is a reticular substance generally used as a dressing formulation to accelerate wound healing, and also used as a bio-applicable scaffold or vehicle. The aim of study is to investigate the effects of PDRN loaded in hydrogel on wound healing, in combination and separately, in an animal diabetic wound model. Methods: We studied the effects of PDRN in diabetes-related healing defect using an incisional skin-wound model produced on the back of male diabetic rats. A total of 36 wounds, were classified into 3 groups: a control group, a hydrogel-only group, a PDRN loaded in hydrogel combined-treatment group. All rats were assessed for changes in wound size and photographed on scheduled dates. The skin specimen sample of diabetic rat wound model were observed on 3, 7, 14 and 21 days after skin injury to measure tissue remodeling through histological evaluation of fibroblasts proliferation, and collagen production, also the number of blood vessels was measured in all specimens. Results: Differences in the decrease and change in wound size in the PDRN loaded in hydrogel group were more significant than those in the control and hydrogel single-treatment groups. Analysis of the fibroblasts proliferation, collagen production and number of blood vessels through histological examination showed a pattern of increase over time that occurred in PDRN loaded in hydrogel combined-treatment group. Conclusion: This experiment demonstrated improved wound healing using a PDRN loaded in hydrogel combined treatment compared to either two groups, resulting in a decrease in diabetic wound size and a shortening of the healing period

Therapeutic potentials of agonist and antagonist of adenosine receptors in type 2 diabetes

Type 2 diabetes has been a global health challenge over the decades and is among the leading causes of death. Several treatment approaches have been developed, but more effective and new therapies are still needed. The role of adenosine in glucose and lipid homeostasis has offered a different therapeutic approach. Adenosine mediates its physiological role through the activation of adenosine receptors. These adenosine receptors have been implicated in glucose and lipid homeostasis. The ability of agonists and antagonists of adenosine receptors to activate or inhibit the adenosine signalling cascade and thereby affecting the balance of glucose and lipid homeostasis has challenged the studies of agonists and antagonists of adenosine receptors, both preclinical and clinical, as potential anti-diabetic drugs. This review provides a background on different anti-diabetic therapeutic approaches, outlining the role of adenosine receptors in glucose and lipid homeostasis, and mechanisms underlying the action of agonists/antagonists of adenosine receptors as a therapeutic potential towards type 2 diabetes.

Comparison of the effectiveness of extensor muscle strengthening exercise by itself, exercise with polydeoxyribonucleotide injection, and exercise with extracorporeal shockwave therapy in lateral epicondylitis: a randomized controlled trial

Background

Extensor muscle strengthening exercises with counterforce braces (EX) is a conventional conservative treatment for lateral epicondylitis (LE) of the elbow. In addition, polydeoxyribonucleotide (PDRN) or extracorporeal shockwave therapy (ESWT) has been recently used for LE.

Methods

Sixty-three patients with chronic LE participated in this study and randomly allocated in three groups (G1: EX, G2: EX+PDRN injection, and G3: EX+ESWT). All of the three groups were taught to perform EX at the first out-patient department (OPD) visit. Group 2 was injected with 3 mL PDRN (5.625 mg/3 mL), while group 3 received ESWT at the first OPD visit. Visual analog scale pain score, Mayo elbow performance score (MEPS), and ultrasonographic examination were checked before, 6 weeks, and 12 weeks after the treatments.

Results

Overall functional scores and ultrasonographic findings in all three groups improved after treatment. The mean MEPS in group 2 improved more than groups 1 and 3 at 6 weeks (G1, 56.9>62.4; G2, 54.3>65.0; G3, 55.7>62.6), and more than group 1 at 12 weeks (G1, 56.9>67.9; G2, 54.3>73.6). The mean common extensor tendon depth (CETD) on ultrasonography in group 2 increased more than groups 1 and 3 at 6 and 12 weeks (6 weeks: G1, 0.385>0.386; G2, 0.332>0.392; G3, 0.334>0.357; 12 weeks: G1, 0.385>0.409; G2, 0.332>0.438; G3, 0.334>0.405 [cm]).

Conclusions

PDRN injections combined with EX exhibited a greater improvement in mean MEPS and mean CETD compared to EX only or EX combined with ESWT for LE within the 12 weeks follow-up.

Polydeoxyribonucleotide: A Promising Biological Platform to Accelerate Impaired Skin Wound Healing

The normal wound healing process is characterized by a complex, highly integrated cascade of events, requiring the interactions of many cell types, including inflammatory cells, fibroblasts, keratinocytes and endothelial cells, as well as the involvement of growth factors and enzymes. However, several diseases such as diabetes, thermal injury and ischemia could lead to an impaired wound healing process characterized by wound hypoxia, high levels of oxygen radicals, reduced angiogenesis, decreased collagen synthesis and organization. Polydeoxyribonucleotide (PDRN) has been used to improve wound healing through local and systemic administration thanks to its ability to promote cell migration and growth, angiogenesis, and to reduce inflammation on impaired wound healing models in vitro, in vivo and clinical studies. In light of all these observations, the aim of this review is to provide a full overview of PDRN applications on skin regeneration. We reviewed papers published in the last 25 years on PubMed, inserting "polydeoxyribonucleotide and wound healing" as the main search term. All data obtained proved the ability of PDRN in promoting physiological tissue repair through adenosine A2A receptor activation and salvage pathway suggesting that PDRN has proven encouraging results in terms of healing time, wound regeneration and absence of side effects.

Polydeoxyribonucleotide and Polynucleotide Improve Tendon Healing and Decrease Fatty Degeneration in a Rat Cuff Repair Model

BACKGROUND

After surgical repair of chronic rotator cuff tears, healing of the repaired tendons often fails and is accompanied by high-level fatty degeneration. Our purpose was to explore the effects of polydeoxyribonucleotide (PDRN) and polynucleotide (PN) on tendon healing and the reversal of fatty degeneration in a chronic rotator cuff tear model using a rat infraspinatus.

METHODS

Sixty rats were randomly assigned to the following three groups (20 rats per group: 12 for histological evaluation and 8 for mechanical testing): saline + repair (SR), PDRN + repair (PR), and PN + repair (PNR). The right shoulder was used for experimental intervention, and the left served as a control. Four weeks after detaching the infraspinatus, the torn tendon was repaired. Saline, PDRN, and PN were applied to the repair sites. Histological evaluation was performed 3 and 6 weeks after repair and biomechanical analysis was performed at 6 weeks.

RESULTS

Three weeks after repair, the PR and PNR groups had more CD168-stained cells than the SR group. The PR group showed a larger cross-sectional area (CSA) of muscle fibers than the SR and PNR groups. Six weeks after repair, the PR and PNR groups showed more adipose cells, less CD68-stained cells, and more parallel tendon collagen fibers than the SR group. The PR group had more CD 68-stained cells than the PNR group. The PR group showed a larger CSA than the SR group. The mean load-to-failure values of the PR and PNR groups were higher than that of the SR group, although these differences were not significant.

CONCLUSION

PDRN and PN may improve tendon healing and decrease fatty degeneration after cuff repair.

Combination treatment of dendrosomal nanocurcumin and low-level laser therapy develops proliferation and migration of mouse embryonic fibroblasts and alter TGF-β, VEGF, TNF-α and IL-6 expressions involved in wound healing process

INTRODUCTION

Pressure ulcer (PU) is known as the third most costly disorder usually caused by prolonged pressure and stagnation in various parts of the body. Although several therapeutic approaches are employing, obstacles in appropriate healing for skin lesions still exist which necessitates new practical alternative or adjunctive treatments. Low level laser therapy (LLLT) as one of the mentioned new strategies have gained attention. Besides, curcumin is an herbal medicine extracted from turmeric with anti-inflammatory and antioxidative properties with promising beneficial therapeutic effects in wound healing. Employing dendrosomal nanoparticles, we overcome the hydrophobicity of curcumin in the present study. We hypothesized that combination treatment of DNC+LLLT (450 nm) simultaneously may promote the wound healing process.

MATERIAL AND METHODS

MTT assay, PI staining followed by flowcytometry, scratch assay and intracellular ROS measurement were used to investigate the effects caused by DNC and LLLT (450 nm) alone and in combination, on proliferation, cell cycle, migration and oxidative stress mouse embryonic fibroblast cells, respectively. The levels of growth factors and pro-inflammatory cytokines were evaluated by qRT-PCR and ELISA.

RESULTS

Our results indicated that combination exposure with DNC and LLLT leads to increased proliferation and migration of MEFs as well as being more efficient in significantly upregulating growth factors (TGF-β, VEGF) and decline in inflammatory cytokines (TNF-α, IL-6). Moreover, findings of this research provide persuasive support for the notion that DNC could reduce the LLLT-induced enhancement in intracellular ROS in mouse embryonic fibroblasts.

CONCLUSION

Concurrent exposure to anti-oxidant concentrations of DNC and LLLT enriched S phase entry and therefor increased proliferation as well as migration on MEFs through regulating the expression levels growth factors and shortening the inflammatory phase by modulating of cytokines. It should be noted that DNC were able to reduce the laser-induced oxidative stress, during wound healing, representing an informative accompaniment with LLLT.

PDRN, a natural bioactive compound, blunts inflammation and positively reprograms healing genes in an "in vitro" model of oral mucositis

Oral mucositis is a side effect hard to treat following high dose chemotherapy or radiotherapy. Adenosine A_2A receptor stimulation blocks NF-κB and boosts the Wnt/β-catenin signaling, thus blunting inflammation and triggering growth factor codifying genes. Polydeoxyribonucleotide (PDRN) is a registered drug that activates the A_2A receptor. Therefore, the aim of this study was to evaluate PDRN effects in an "in vitro" model of oral mucositis induced by prompting an inflammatory phenotype in human gingival fibroblasts (GF) and human oral mucosal epithelial cells (EC). GF and EC were stimulated with LPS (2 μg/ml) alone or in combination with i) PDRN (100 μg/ml); ii) PDRN plus ZM241385 (1 μM) as an A_2AR antagonist; iii) CGS21680 (1 μM) as an A_2AR agonist. LPS boosted NF-κB, TNF-α and IL-6 expression, decreased IL-10 levels and downregulated both Wnt/β-catenin, VEGF and EGF expression. PDRN reverted the LPS-induced phenotype as well as CGS21680. Co-incubation with ZM241385 abolished PDRN effects, thus confirming A_2A receptor involvement in PDRN mechanism of action. These results suggest that PDRN efficacy may be due to a "dual mode" of action: NF-κB inhibition and Wnt/β-catenin signaling activation. However, these interesting findings need to be confirmed by animal and clinical studies.

Evaluation of Wound-Healing and Antioxidant Effects of Marantodes pumilum (Blume) Kuntze in an Excision Wound Model

Marantodes pumilum (MP) is a great source of herbal medicine used traditionally by both men and women for various purposes. MP may have potential wound-healing effects due to its diverse biological properties. An extensive study was conducted in a normal male rat model for determining the effects of MP var. pumila (MPvp) and var. alata (MPva) on the wound healing process. Here, 126 male Sprague-Dawley rats were divided randomly into seven groups as follows: sham-operated (SH), vehicle dressing (VD), flavine dressing (FD), MPvp leaves (PL), MPvp roots (PR), MPva leaves (AL), and MPva roots (AR). The parameters studied were the percentage of wound contraction, histomorphology study by hematoxylin and eosin (H&E), Masson–Goldner trichrome (MGT), and immunohistochemistry (IHC) staining. In addition, the levels of enzymatic antioxidants and malondialdehyde were also measured in the wound tissue homogenates. Wounds treated with extracts (PL, PR, AL, and AR) showed significantly faster healing (p < 0.05) compared to untreated and control groups (SH, VD, and FD). Histological analysis among MP-treated groups revealed better re-epithelialization, higher collagen deposition, enhanced fibronectin content and fibroblast cells, and higher fiber transformation from collagen-III to collagen-I, accompanied with a significant surge in enzymatic antioxidant activities and a decline in lipid peroxidation. MP has antioxidant effects that may enhance wound healing in the rat model.

Recent Advances in Clinical Translation of Intra-Articular Osteoarthritis Drug Delivery Systems

Osteoarthritis (OA) is a degenerative disease of the joints and a leading cause of physical disability in adults. Intra-articular (IA) therapy is a popular treatment strategy for localized, single-joint OA; however, small-molecule drugs such as corticosteroids do not provide prolonged relief. One possible reason for their lack of efficacy is high clearance rates from the joint through constant lymphatic drainage of the synovial tissues and synovial fluid and also by their exchange via the synovial vasculature. Advanced drug delivery strategies for extended release of therapeutic agents in the joint space is a promising approach to improve outcomes for OA patients. Broadly, the basic principle behind this strategy is to encapsulate therapeutic agents in a polymeric drug delivery system (DDS) for diffusion- and/or degradation-controlled release, whereby degradation can occur by hydrolysis or tied to relevant microenvironmental cues such as pH, reactive oxygen species (ROS), and protease activity. In this review, we highlight the development of clinically tested IA therapies for OA and highlight recent systems which have been investigated preclinically. DDS strategies including hydrogels, liposomes, polymeric microparticles (MPs) and nanoparticles (NPs), drug conjugates, and combination systems are introduced and evaluated for clinical translational potential.

Polydeoxyribonucleotide for the improvement of a hypertrophic retracting scar-An interesting case report

Background

Post‐surgery disabling scars are frequent after surgical interventions.

Aim

We evaluated a new strategy for scars management.

Methods

A woman with a postsurgery disabling scar, consequent to an accident that needed surgical intervention, had serious difficulties to walk and perform normal daily activities. A few months after the intervention, she was treated with a combined therapy consisting of polydeoxyribonucleotide (PDRN) vials 5.625 mg/3 mL (administered subcutaneously as a biostimulant treatment through the scars and throughout the whole atrophic area), associated with nucleotide administered topically and as a food supplement. The patient was treated with an additional topical nighttime treatment cream based on nucleotides, hyaluronic acid, Allium cepa extract, and vitamin E, plus a daily treatment with a cream containing nucleotides, and a nutraceutical systemic treatment with 25 mg/cps of nucleotides and 5 mg/cps of Q10‐coenzyme (1 cps/d).

Results

This reasonably cheap treatment was effective and safe for this disabling scar at the right foot. One year after starting treatment, the patient confirmed her complete satisfaction. This is the first case report describing an unexpectedly successful outcome while using this combination therapy on a woman with a postsurgery disabling scar.

The effects of polydeoxyribonucleotide on wound healing and tissue regeneration: a systematic review of the literature

Aim: The present study evaluated the effects of polydeoxyribonucleotide (PDRN) on tissue regeneration, paying special attention to the molecular mechanisms that underlie its tissue remodeling actions to better identify its effective therapeutic potential in wound healing. Materials & methods: Strategic searches were conducted through MEDLINE/PubMed, Google Scholar, Scopus, Web of Science and the Cochrane Central Register of Controlled Trials, from their earliest available dates to March 2020. The studies were included with the following eligibility criteria: studies evaluating tissue regeneration, and being an in vitro, in vivo and clinical study. Results: Out of more than 90 articles, 34 fulfilled the eligibility criteria. All data obtained proved the ability of PDRN in promoting a physiological tissue repair through salvage pathway and adenosine A2A receptor activation. Conclusion: Up to date PDRN has proved promising results in term of wound regeneration, healing time and absence of side effects.

PDRN, a Bioactive Natural Compound, Ameliorates Imiquimod-Induced Psoriasis through NF-κB Pathway Inhibition and Wnt/β-Catenin Signaling Modulation

Nuclear factor-κB (NF-κB) plays a central role in psoriasis and canonical Wnt/β-catenin pathway blunts the immune-mediated inflammatory cascade in psoriasis. Adenosine A2A receptor activation blocks NF-κB and boosts the Wnt/β-catenin signaling. PDRN (Polydeoxyribonucleotide) is a biologic agonist of the A2A receptor and its effects were studied in an experimental model of psoriasis. Psoriasis-like lesions were induced by a daily application of imiquimod (IMQ) on the shaved back skin of mice for 7 days. Animals were randomly assigned to the following groups: Sham psoriasis challenged with Vaseline; IMQ animals challenged with imiquimod; and IMQ animals treated with PDRN (8 mg/kg/ip). An additional arm of IMQ animals was treated with PDRN plus istradefylline (KW6002; 25 mg/kg/ip) as an A2A antagonist. PDRN restored a normal skin architecture, whereas istradefylline abrogated PDRN positive effects, thus pointing out the mechanistic role of the A2A receptor. PDRN decreased pro-inflammatory cytokines, prompted Wnt signaling, reduced IL-2 and increased IL-10. PDRN also reverted the LPS repressed Wnt-1/β-catenin in human keratinocytes and these effects were abolished by ZM241385, an A2A receptor antagonist. Finally, PDRN reduced CD3+ cells in superficial psoriatic dermis. PDRN anti-psoriasis potential may be linked to a “dual mode” of action: NF-κB inhibition and Wnt/β-catenin stimulation.

Polydeoxyribonucleotides Improve Diabetic Wound Healing in Mouse Animal Model for Experimental Validation

Background

Wound healing mechanisms is believed to have effects similar to wound healing disorders in diabetic patients, including abnormal inflammatory cells, angiogenesis disorders, and reduced collagen synthesis. Therefore, reestablishment of structural and promoted angiogenesis could be beneficial to promote wound healing process.

Objective

Therefore, we investigated whether the polydeoxyribonucleotide (PDRN) that was self-production in Korea, could be useful as an intradermal injection for promoting wound healing. Also, we validate for wound healing effect of PDRN using healing-impaired (db/db) mice.

Methods

In this study, we confirmed the effects of PDRN by creating wound models in in vitro and in vivo model. Using an in vitro wound healing assay, we observed that PDRN stimulated closure of wounded monolayers of human fibroblast cells. PDRN (8.25 mg/ml) or phosphate-buffered saline (0.9% NaCl) was injected once daily into the dermis adjacent to the wound for 12 days after skin injury.

Results

Time course observations revealed that mice treated with PDRN showed accelerated wound closure and epidermal and dermal regeneration, enhanced angiogenesis. The wound area and depth decreased at 3, 6, 9, and 12 days after skin injury. Histological evaluation showed an increase of vascular endothelial growth factor, CD31, and collagen fibers in the PDRN group compared with the control group, indicating that PDRN was effective in the treatment of delayed wound healing caused by diabetes.

Conclusion

This study suggests that our PDRN has a wound healing effect in transgenic animal models with cells and diabetes through angiogenesis.

Loss of ENT1 increases cell proliferation in the annulus fibrosus of the intervertebral disc

Mice lacking equilibrative nucleoside transporter 1 (ENT1 ^-/- ) demonstrate progressive calcification of spinal tissues including the annulus fibrosus (AF) of the intervertebral disc (IVD). We previously established ENT1 as the primary nucleoside transporter in the AF and demonstrated dysregulation of biomineralization pathways. To identify cellular pathways altered by loss of ENT1, we conducted microarray analysis of AF tissue from wild-type (WT) and ENT1 ^-/- mice before calcification (2 months of age) and associated with calcification (6 months of age). Bioinformatic analyses identified cell cycle dysregulation in ENT1 ^-/- AF tissues and implicated the E2f family of transcription factors as potential effectors. Quantitative polymerase chain reaction analysis confirmed increased expression of multiple E2f transcription factors and E2f interacting proteins ( Rb1 and Cdk2) in ENT1 ^-/- AF cells compared with WT at 6 months of age. At this time point, ENT1 ^-/- AF tissues showed increased JNK MAPK pathway activation, CDK1, minichromosome maintenance complex component 5 (Mcm5), and proliferating cell nuclear antigen (PCNA) protein expression, and PCNA-positive proliferating cells compared with WT controls. The current study demonstrates that loss of ENT1-mediated adenosine transport leads to increased cell proliferation in the AF of the IVD.

An effective range of polydeoxyribonucleotides is critical for wound healing quality

Wound healing is a physiological restorative response to tissue and cell injury. This process occurs in collaboration with a complex cascade of cellular events, including biochemical alterations to the extracellular matrix. Polydeoxyribonucleotide (PDRN) is a fragmented DNA mixture from Oncorhynchus mykiss or Oncorhynchus keta sperm known to promote tissue regeneration under different pathophysiological conditions. However, the most effective molecular size of PDRNs for promoting the wound healing process and quality has not been established. In the present study, the regeneration quality with low (<50 kDa), middle [classic PDRN; 50‑1,500 kDa] and high (>1,500 kDa) molecular weight PDRNs in a skin wound healing mouse model was examined using hematoxylin and eosin, as well as Masson's trichrome stain. A 4 mm biopsy punch was used to produce wounds in the skin of the mice. PDRN‑mediated cellular behavior and signaling were evaluated by in vitro scratch assay and western blot analysis, respectively. It was observed that the apparent surface wound healing processes were not significantly different between PDRN molecular sizes. Immunohistochemical analysis revealed that classic PDRN‑injected mice exhibited less lipid accumulation with increased collagen composition. These results suggested that 50‑1,500 kDa PDRN offers an effective DNA mixture to improve wound healing quality. Furthermore, classic PDRN increased cell migration via c‑Jun N‑terminal kinase signaling in human fibroblasts. The present study suggests an optimal PDRN molecular weight to promote wound healing, and novel approaches for therapeutic strategies to improve tissue regeneration quality.

Neuroprotective Effects of Polydeoxyribonucleotide in a Murine Model of Cadmium Toxicity

Cadmium (Cd) is a harmful heavy metal, which causes severe brain damage and neurotoxic effects. Polydeoxyribonucleotide (PDRN) stimulates adenosine A_2A receptor, thus contrasting several deleterious mechanisms in course of tissue damages. We aimed to investigate the possible neuroprotective effect of PDRN in a murine model of Cd-induced brain toxicity. Male C57 BL/6J mice were treated as follows: vehicle (0.9% NaCl, 1 ml/kg/day), PDRN (8 mg/kg/day), CdCl₂ (2 mg/kg/day), and CdCl₂ + PDRN. Animals were tested with the Morris water maze test to assess spatial memory and learning. After 14 days of treatment, brains were processed to evaluate the presence of edema in the cerebral tissue, the expression of mammalian target of rapamycin kinase (mTOR) and brain-derived neurotrophic factor (BDNF), and the morphological behavior of the hippocampal structures. After CdCl₂ administration, the escape latency was high, protein expression of BDNF was significantly decreased if compared to controls, mTOR levels were higher than normal controls, and brain edema and neuronal damages were evident. The coadministration of CdCl₂ and PDRN significantly diminished the escape latency, increased BDNF levels, and decreased protein expression of mTOR. Furthermore, brain edema was reduced and the structural organization and the number of neurons, particularly in the CA1 and CA3 hippocampal areas, were improved. In conclusion, a functional, biochemical, and morphological protective effect of PDRN against Cd induced toxicity was demonstrated in mouse brain.

Heparan sulfate inhibits inflammation and improves wound healing by downregulating the NLR family pyrin domain containing 3 (NLRP3) inflammasome in diabetic rats

BACKGROUND

Heparan sulfate (HS) attenuates the inflammatory response and improves diabetic wound healing in rats. However, the specific mechanisms by which HS suppresses inflammation are not clear. Given that NLR family pyrin domain containing 3 (NLRP3) is a major receptor involved in innate immune regulation, the aim of the present study was to elucidate the effects of HS on NLRP3 and proinflammatory cytokines in diabetic wounds.

METHODS

Full-thickness wounds were created on the back of diabetic rats. The experimental group received HS treatment (1 mg/kg, i.m., on Days 0 and 7), whereas the control group received vehicle (0.1% dimethylsulfoxide in 0.9% NaCl). Expression of NLRP3 and its downstream effector molecules, namely cleaved interleukin (IL)-1β, IL-18, tumor necrosis factor (TNF)-α, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), proteinase inhibitor 9, and caspase-12, in the wound tissues was examined.

RESULTS

Treatment with HS accelerated wound healing in diabetic rats. Rats treated with HS exhibited decreased activation of cleaved IL-1β, IL-18, and TNF-α, as well as decreased expression of NLRP3 and ASC. In addition, HS increased levels of proteinase inhibitor 9 and caspase-12.

CONCLUSIONS

Heparan sulfate inhibits inflammation and improves wound healing by downregulating the NLRP3 inflammasome and cleaved IL-1β during the wound healing process in diabetic rats.

Polydeoxyribonucleotide improves tendon healing following achilles tendon injury in rats

Tendon injuries are major musculoskeletal disorders. Polydeoxyribonucleotide activates the adenosine receptor subtype A2A, resulting in tissue growth and neogenesis. This experimental study confirms that polydeoxyribonucleotide can improve secretion of various growth factors, promote collagen synthesis, and restore tensile strength of the Achilles tendon in a rat model with Achilles tendon injury. Thirty-six male Sprague-Dawley rats, aged 7 weeks, were divided into two groups, and the Achilles tendon was transected and repaired using the modified Kessler's method. In the experimental group (n = 18), the rats received daily intraperitoneal administration of polydeoxyribonucleotide (8 mg/kg/day for 1, 2, or 4 weeks). The control groups received the same amount of normal saline. The rats were euthanized at 1, 2, and 4 weeks, and tissues from the repair site were harvested. The cross-sectional area of the tendon was significantly increased at 2 and 4 weeks in polydeoxyribonucleotide group (p = 0.008 and p = 0.017, respectively). Moreover, tendons in the polydeoxyribonucleotide group were more resistant to mechanical stress at 2 and 4 weeks (p = 0.041 and p = 0.041, respectively). The staining levels of collagen type I in the experimental group were significantly stronger at 2 and 4 weeks (p = 0.026 and p = 0.009, respectively). Furthermore, higher expression levels of fibroblast growth factor, vascular endothelial growth factor, and transforming growth factor β1 were detected in the experimental group at 4 weeks (p = 0.041, p = 0.026, and p = 0.041, respectively). This study confirms that polydeoxyribonucleotide can improve the tensile strength of the rats' Achilles tendon following injury and repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1767-1776, 2018.

NF-κB signaling is key in the wound healing processes of silk fibroin

Silk fibroin (SF) is a well-studied biomaterial for tissue engineering applications including wound healing. However, the signaling mechanisms underlying the impact of SF on this phenomenon have not been determined. In this study, through microarray analysis, regulatory genes of NF-ĸB signaling were activated in SF-treated NIH3T3 cells along with other genes. Immunoblot analysis confirmed the activation of the NF-ĸB signaling pathway as SF induced protein expression levels of IKKα, IKKβ, p65, and the degradation of IκBα. The treatment of NIH3T3 cells with SF also increased the expression of cyclin D1, vimentin, fibronectin, and vascular endothelial growth factor (VEGF). The expression of these factors by SF treatment was abrogated when NF-ĸB was inhibited by a pharmacological inhibitor Bay 11-7082. Knockdown of NF-ĸB using siRNA of IKKα and IKKβ also inhibited the SF-induced wound healing response of the NIH3T3 cells in a wound scratch assay. Collectively, these results indicated that SF-induced wound healing through the canonical NF-κB signaling pathway via regulation of the expression of cyclin D1, vimentin, fibronectin, and VEGF by NIH3T3 cells. Using an in vivo study with a partial-thickness excision wound in rats we demonstrated that SF-induced wound healing via NF-κB regulated proteins including cyclin D1, fibronectin, and VEGF. The in vitro and in vivo data suggested that SF induced wound healing via modulation of NF-ĸB signaling regulated proteins.

STATEMENT OF SIGNIFICANCE

Silk fibroin has been effectively used as a dressing for wound treatment for more than a century. However, mechanistic insight into the basis for wound healing via silk fibroin has not been elucidated. Here we report a key mechanism involved in silk fibroin induced wound healing both in vitro and in vivo. Using genetic- and protein-level analyses, NF-κB signaling was found to regulate silk fibroin-induced wound healing by modulating target proteins. Thus, the NF-κB signaling pathway may be utilized as a therapeutic target during the formulation of silk fibroin-based biomaterials for wound healing and tissue engineering.

Scar Prevention and Enhanced Wound Healing Induced by Polydeoxyribonucleotide in a Rat Incisional Wound-Healing Model

High-mobility group box protein-1 (HMGB-1) plays a central role in the inflammatory network, and uncontrolled chronic inflammation can lead to excessive scarring. The aim of this study was to evaluate the anti-inflammatory effects of polydeoxyribonucleotide (PDRN) on scar formation. Sprague-Dawley rats (n = 30) underwent dorsal excision of the skin, followed by skin repair. PDRN (8 mg/kg) was administered via intraperitoneal injection for three (PDRN-3 group, n = 8) or seven (PDRN-7 group, n = 8) days, and HMGB-1 was administered via intradermal injection in addition to PDRN treatment for three days (PDRN-3+HMGB-1 group; n = 6). The scar-reducing effects of PDRN were evaluated in the internal scar area and by inflammatory cell counts using histology and immunohistochemistry. Western blot, immunohistochemistry and immunofluorescence assays were performed to observe changes in type I and type III collagen and the expression of HMGB-1 and CD45. Treatment with PDRN significantly reduced the scar area, inflammatory cell infiltration and the number of CD45-positive cells. In addition, the increased expression of HMGB-1 observed in the sham group was significantly reduced after treatment with PDRN. Rats administered HMGB-1 in addition to PDRN exhibited scar areas with inflammatory cell infiltration similar to the sham group, and the collagen synthesis effects of PDRN were reversed. In summary, PDRN exerts anti-inflammatory and collagen synthesis effects via HMGB-1 suppression, preventing scar formation. Thus, we believe that the anti-inflammatory and collagen synthesis effects of PDRN resulted in faster wound healing and decreased scar formation.

Pharmacological Activity and Clinical Use of PDRN

PDRN is a proprietary and registered drug that possesses several activities: tissue repairing, anti-ischemic, and anti-inflammatory. These therapeutic properties suggest its use in regenerative medicine and in diabetic foot ulcers. PDRN holds a mixture of deoxyribonucleotides with molecular weights ranging between 50 and 1,500 KDa, it is derived from a controlled purification and sterilization process of Oncorhynchus mykiss (Salmon Trout) or Oncorhynchus keta (Chum Salmon) sperm DNA. The procedure guarantees the absence of active protein and peptides that may cause immune reactions. In vitro and in vivo experiments have suggested that PDRN most relevant mechanism of action is the engagement of adenosine A_2A receptors. Besides engaging the A_2A receptor, PDRN offers nucleosides and nucleotides for the so called “salvage pathway.” The binding to adenosine A_2A receptors is a unique property of PDRN and seems to be linked to DNA origin, molecular weight and manufacturing process. In this context, PDRN represents a new advancement in the pharmacotherapy. In fact adenosine and dipyridamole are non-selective activators of adenosine receptors and they may cause unwanted side effects; while regadenoson, the only other A_2A receptor agonist available, has been approved by the FDA as a pharmacological stress agent in myocardial perfusion imaging. Finally, defibrotide, another drug composed by a mixture of oligonucleotides, has different molecular weight, a DNA of different origin and does not share the same wound healing stimulating effects of PDRN. The present review analyses the more relevant experimental and clinical evidences carried out to characterize PDRN therapeutic effects.

Polydeoxyribonucleotides (PDRNs) From Skin to Musculoskeletal Tissue Regeneration via Adenosine A2A Receptor Involvement

Polydeoxyribonucleotides (PDRNs) are low molecular weight DNA molecules of natural origin that stimulate cell migration and growth, extracellular matrix (ECM) protein production, and reduce inflammation. Most preclinical and clinical studies on tissue regeneration with PDRNs focused on skin, and only few are about musculoskeletal tissues. Starting from an overview on skin regeneration studies, through the analysis of in vitro, in vivo, and clinical studies (1990-2016), the present review aimed at defining the effects of PDRN and their mechanisms of action in the regeneration of musculoskeletal tissues. This would also help future researches in this area. A total of 29 studies were found by PubMed and www.webofknowledge.com searches: 20 were on skin (six in vitro, six in vivo, one vitro/vivo, seven clinical studies), while the other nine regarded bone (one in vitro, two in vivo, one clinical studies), cartilage (one in vitro, one vitro/vivo, two clinical studies), or tendon (one clinical study) tissues regeneration. PDRNs improved cell growth, tissue repair, ECM proteins, physical activity, and reduced pain and inflammation, through the activation of adenosine A_2A receptor. PDRNs are currently used for bone, cartilage, and tendon diseases, with a great variability regarding the PDRN dosage to be used in clinical practice, while the dosage for skin regeneration is well established. PDRNs are usually administered from a minimum of three to a maximum of five times and they act trough the activation of A_2A receptor. Further studies are advisable to confirm the effectiveness of PDRNs and to standardize the PDRN dose. J. Cell. Physiol. 232: 2299-2307, 2017. © 2016 Wiley Periodicals, Inc.

Polydeoxyribonucleotide Injection in the Treatment of Chronic Supraspinatus Tendinopathy: A Case-Controlled, Retrospective, Comparative Study With 6-Month Follow-Up

OBJECTIVE

To determine the efficacy of polydeoxyribonucleotide (PDRN) injection for rotator cuff disease (RCD).

DESIGN

Case-controlled, retrospective, comparative study.

SETTING

Outpatient clinic at a university-affiliated tertiary care hospital.

PARTICIPANTS

Patients (N=106) with chronic nontraumatic refractory RCD who were unresponsive to at least 1 month of conservative treatment: 55 patients received PDRN injection (PDRN group) and 51 continued conservative treatment (control group).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Shoulder Pain and Disability Index, score on a visual analog scale of the average shoulder pain level, number of analgesic ingestions per day, isometric strength of shoulder abductor, active range of motion (flexion, abduction, internal rotation, external rotation), and maximal tear size of tendon on ultrasonography at pretreatment and 3 and 6 months postinjection.

RESULTS

There was no significant difference between the 2 groups in terms of age, sex, shoulder affected, duration of symptoms, and ultrasonographic findings at pretreatment. Compared with the control group, the treatment group showed a significant improvement in Shoulder Pain and Disability Index, visual analog scale score, and number of analgesic ingestions per day. However, there was no difference in isometric strength, active range of motion, and maximal tear size of tendon. No adverse events were reported.

CONCLUSIONS

To our knowledge, this is the first study to assess the efficacy of PDRN injection for patients with RCD. The PDRN injection group showed improvement in pain and subjective disability in patients with RCD and continued to show improvement for 3 months thereafter; the PDRN injection can be an optional treatment for patients with chronic RCD who show no response to other treatments.

Adenosine Receptor Stimulation by Polydeoxyribonucleotide Improves Tissue Repair and Symptomology in Experimental Colitis

Activation of the adenosine receptor pathway has been demonstrated to be effective in improving tissue remodeling and blunting the inflammatory response. Active colitis is characterized by an intense inflammatory reaction resulting in extensive tissue damage. Symptomatic improvement requires both control of the inflammatory process and repair and remodeling of damaged tissues. We investigated the ability of an A2A receptor agonist, polydeoxyribonucleotide (PDRN), to restore tissue structural integrity in two experimental colitis models using male Sprague-Dawley rats. In the first model, colitis was induced with a single intra-colonic instillation of dinitrobenzenesulfonic acid (DNBS), 25 mg diluted in 0.8 ml 50% ethanol. After 6 h, animals were randomized to receive either PDRN (8 mg/kg/i.p.), or PDRN + the A2A antagonist [3,7-dimethyl-1-propargylxanthine (DMPX); 10 mg/kg/i.p.], or vehicle (0.8 ml saline solution) daily. In the second model, dextran sulfate sodium (DSS) was dissolved in drinking water at a concentration of 8%. Control animals received standard drinking water. After 24 h animals were randomized to receive PDRN or PDRN+DMPX as described above. Rats were sacrificed 7 days after receiving DNBS or 5 days after DSS. In both experimental models of colitis, PDRN ameliorated the clinical symptoms and weight loss associated with disease as well as promoted the histological repair of damaged tissues. Moreover, PDRN reduced expression of inflammatory cytokines, myeloperoxidase activity, and malondialdehyde. All these effects were abolished by the concomitant administration of the A2A antagonist DMPX. Our study suggests that PDRN may represent a promising treatment for improving tissue repair during inflammatory bowel diseases.

Promotion of Wound Healing by an Agonist of Adenosine A2A Receptor Is Dependent on Tissue Plasminogen Activator

Impaired wound healing, as it occurs in diabetes mellitus or long-term corticoid treatment, is commonly associated with disability, diminished quality of life, and high economic costs. Selective agonists of the A2A receptor subtype of adenosine, an endogenous regulator of inflammation, promote tissue repair in animal models, both healthy and with impaired healing. Plasmin-mediated proteolysis of fibrin and other matrix proteins is essential for cell migration at sites of injury. Since adenosine A2A receptor activation increases plasminogen activator release from macrophages and mast cells, we studied the effect of a selective agonist, CGS-21680, on full-thickness excisional wound closure in wild-type, urokinase plasminogen activator (uPA)-deficient, and tissue plasminogen activator (tPA)-deficient mice. Wound closure was impaired in tPA- and uPA-deficient mice as compared with wild-type mice, and topical application of CGS-21680 significantly increased the rate at which wounds closed in wild-type mice and uPA-deficient mice, but not in tPA-deficient mice. Immunostaining of tissue sections showed that tPA was present in endothelial cells and histiocytes by day 3 post-wound and also by day 6. In contrast, uPA was more prominent in these cell types only by day 6 post-wound. Our results confirm that plasminogen activation contributes to wound repair and are consistent with the hypothesis that adenosine A2A receptor activation promotes wound closure by a mechanism that depends upon tPA, but not uPA. Moreover, our results suggest that topical adenosine A2A receptor agonists may be useful in promotion of wound closure in patients with impaired wound healing.

Curcuma purpurascens BI. rhizome accelerates rat excisional wound healing: involvement of Hsp70/Bax proteins, antioxidant defense, and angiogenesis activity

PURPOSE

Curcuma purpurascens BI. is a member of Zingiberaceae family. The purpose of this study is to investigate the wound healing properties of hexane extract of C. purpurascens rhizome (HECP) against excisional wound healing in rats.

MATERIALS AND METHODS

Twenty four rats were randomly divided into 4 groups: A) negative control (blank placebo, acacia gum), B) low dose of HECP, C) high dose of HECP, and D) positive control, with 6 rats in each group. Full-thickness incisions (approximately 2.00 cm) were made on the neck area of each rat. Groups 1-4 were treated two-times a day for 20 days with blank placebo, HECP (100 mg/kg), HECP (200 mg/kg), and intrasite gel as a positive control, respectively. After 20 days, hematoxylin and eosin and Masson's trichrome stainings were employed to investigate the histopathological alterations. Protein expressions of Bax and Hsp70 were examined in the wound tissues using immunohistochemistry analysis. In addition, levels of enzymatic antioxidants and malondialdehyde representing lipid peroxidation were measured in wound tissue homogenates.

RESULTS

Macroscopic evaluation of wounds showed conspicuous elevation in wound contraction after topical administration of HECP at both doses. Moreover, histopathological analysis revealed noteworthy reduction in the scar width correlated with the enhanced collagen content and fibroblast cells, accompanied by a reduction of inflammatory cells in the granulation tissues. At the molecular level, HECP facilitates wound-healing process by downregulating Bax and upregulating Hsp70 protein at the wound site. The formation of new blood vessel was observed in Masson's trichrome staining of wounds treated with HECP (100 and 200 mg/kg). In addition, HECP administration caused a significant surge in enzymatic antioxidant activities and a decline in lipid peroxidation.

CONCLUSION

These findings suggested that HECP accelerated wound-healing process in rats via antioxidant activity, angiogenesis effect and anti-inflammatory responses involving Hsp70/Bax.

Role of Inhibitors of Apoptosis Proteins in Testicular Function and Male Fertility: Effects of Polydeoxyribonucleotide Administration in Experimental Varicocele

Neuronal apoptosis inhibitory protein (NAIP) and survivin might play an important role in testicular function. We investigated the effect of PDRN, an agonist of adenosine A2A receptor, on testicular NAIP and survivin expression in an experimental model of varicocele. After the creation of experimental varicocele (28 days), adolescent male Sprague-Dawley rats were randomized to one of the following treatments lasting 21 days: vehicle, PDRN (8 mg/kg i.p., daily), PDRN + 3,7-dimethyl-propargylxanthine (DMPX, a specific adenosine A2A-receptor antagonist, 0.1 mg/kg i.p., daily), varicocelectomy, and varicocelectomy + PDRN (8 mg/kg i.p., daily). Sham-operated animals were used as controls. Animals were then euthanized and testis expression of NAIP and survivin was evaluated through qRT-PCR, western blot, and immunohistochemical analysis. Spermatogenetic activity was also assessed. NAIP and survivin expressions were significantly reduced following varicocele induction when compared to sham animals whereas PDRN-treated rats showed an increase in NAIP and survivin levels. Immunohistochemistry revealed an enhanced expression of NAIP and survivin with a characteristic pattern of cellular localization following PDRN treatment. Moreover, administration of PDRN significantly restored spermatogenic function in varicocele rats. PDRN may represent a rational therapeutic option for accelerating recovery from depressed testicular function through a strategic modulation of apoptosis in experimental varicocele.

Adenosine accelerates the healing of diabetic ischemic ulcers by improving autophagy of endothelial progenitor cells grown on a biomaterial

Endothelial progenitor cells (EPCs) seeded on biomaterials can effectively promote diabetic ischemic wound healing. However, the function of transplanted EPCs is negatively affected by a high-glucose and ischemic microenvironment. Our experiments showed that EPC autophagy was inhibited and mitochondrial membrane potential (MMP) was increased in diabetic patients, while adenosine treatment decreased the energy requirements and increased the autophagy levels of EPCs. In animal experiments, we transplanted a biomaterial seeded with EPCs onto the surface of diabetic wounds and found that adenosine-stimulated EPCs effectively promoted wound healing. Increased microvascular genesis and survival of the transplanted cells were also observed in the adenosine-stimulated groups. Interestingly, our study showed that adenosine increased the autophagy of the transplanted EPCs seeded onto the biomaterial and maintained EPC survival at 48 and 96 hours. Moreover, we observed that adenosine induced EPC differentiation through increasing the level of autophagy. In conclusion, our study indicated that adenosine-stimulated EPCs seeded onto a biomaterial significantly improved wound healing in diabetic mice; mechanistically, adenosine might maintain EPC survival and differentiation by increasing high glucose-inhibited EPC autophagy and maintaining cellular energy metabolism.

Viscoelastic interactions between polydeoxyribonucleotide and ophthalmic excipients

This study investigated the interaction between polydeoxyribonucleotide (PDRN) and several ionic and nonionic isotonic agents, thickeners and a preservative that were employed as excipients in ophthalmic preparations. Interaction of each individual excipient and PDRN aqueous solution was evaluated by analyzing their rheological properties. Rheological properties of PDRN solutions were evaluated by dynamic oscillatory shear tests and values of elastic modulus (G'), viscous modulus (G″) and loss tangent (tan δ) were used to assess the relative changes in viscoelastic properties. At given concentrations, sodium chloride was found to show alteration in viscoelastic properties of PDRN solution while nonionic isotonic agents like d-glucose and d-sorbitol did not alter them. Similarly, nonionic water soluble polymers like polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose (HPMC) also did not interact with PDRN to alter the viscoelastic properties. However, there were changes observed when carbopol 940 was used as a thickener. Therefore, PDRN was found to interact with ionic excipients and the interactions were negligible when nonionic materials were examined, which suggests that nonionic excipients are suitable to be formulated with PDRN.

Inhibition of inflammasome activation improves the impaired pattern of healing in genetically diabetic mice

BACKGROUND AND PURPOSE

Type 2 diabetes impairs the healing process because of an exaggerated and persistent inflammatory response, and an altered expression pattern of angiogenic molecules. We investigated the effects of inflammasome blockade in diabetes-related wound-healings defects, in genetically diabetic mice.

EXPERIMENTAL APPROACH

An incisional skin wound model was produced on the back of female diabetic C57BL/KsJ-m +/+ Lept(db) mice (db⁺ /db⁺) and their normal littermates (db⁺ /m⁺). Animals were treated daily with two inflammasome blocking agents, BAY 11-7082 (20  mg·kg⁻¹ i.p.), or Brilliant Blue G (BBG, 45.5 mg·kg⁻¹ i.p.), or vehicle. Mice were killed on 3, 6 and 12 days after skin injury to measure expression of the NOD-like receptor NLRP3, caspase-1, VEGF, the inflammasome adapter protein apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and the chemokine CXCL12. Wound levels of IL-1β and IL-18 were also measured, along with histological assessments of wound tissue and the time to complete wound closure.

KEY RESULTS

During healing, the diabetic mice exhibited increased activation of NLRP3, caspase-1, ASC, IL-1β and IL-18. They also showed a reduced expression of VEGF and CXCL12.Treatment with BAY 11-7082 or BBG, to block activation of the inflammasome, decreased the levels of pro-inflammatory molecules. Histological evaluation indicated that inflammasome blockade improved the impaired healing pattern, at day 12 in diabetic mice, along with a decreased time to complete skin healing.

CONCLUSIONS AND IMPLICATIONS

These data strongly suggest that activation of the NLRP3 inflammasome is one of the key contributors to the delayed healing of wounds in diabetic mice.

Trophic effects of polynucleotides and hyaluronic acid in the healing of venous ulcers of the lower limbs: a clinical study

The aim of this study was to evaluate the results of treatment of venous lower limbs ulcers through the topical application of polynucleotides and hyaluronic acid gel (PNHA): Nucliaskin S™ (Mastelli srl, San Remo, Italy). This study was carried out in 39 consecutive patients who were randomly allocated to two groups: group I (20 patients) received treatment with PNHA (topical gel application two times a week, for a total of 6 weeks); group II (19 patients) received only hyaluronic acid (HA) topical application. All patients received a surgical debridement of the ulcerative lesions before topical treatment with PNHA or HA. Pre-treatment data indicated the area of ulceration. The number of healed ulcers and the variation in area of ulceration were considered as endpoints. The endpoints were observed after 45 days from the beginning of treatment. Complete wound healing occurred in 60% of limbs of group I and in 22% of those of group II patients. The average area reduction was 67% versus 34% in patients of group I and II, respectively. No side effects were recorded in both groups. Our experience shows that PNHA has an elevated trophic effect and speeds the healing rate of venous lower limb ulcers. This treatment may be a valid option in clinical practice.

The effect of PDRN, an adenosine receptor A2A agonist, on the healing of chronic diabetic foot ulcers: results of a clinical trial

CONTEXT

Foot ulcer is the principal cause of hospitalization for patients with diabetes. Polydeoxyribonucleotide (PDRN), an adenosine A2A receptor agonist, improves wound healing in diabetic mice.

OBJECTIVE

The aim of this study was to evaluate the effect of PDRN on chronic ulcer healing in patients with diabetes.

DESIGN AND SETTING

This randomized, double-blind, placebo-controlled trial, involved two medical centers in Italy.

INTERVENTION

Patients with diabetes showing hard-to-heal ulcers (Wagner grade 1 or 2) were randomly assigned to receive placebo (n = 106) or PDRN (n = 110). The treatments (PDRN and placebo) were performed for 8 weeks by intramuscular and perilesional route [corrected].

MAIN OUTCOME MEASURES

The primary outcome was complete ulcer healing. Secondary outcomes were the days needed to complete wound closure and the reepithelialization of wound surface (as percentage of the original area).

RESULTS

After 8 weeks, 91 placebo and 101 PDRN subjects completed the study. Complete healing was achieved in 18.9% [95% confidence interval (CI) 11.4-26.3] of placebo and in 37.3% (95% CI 28.2-46.3) of PDRN-treated patients (P = .0027). After 8 weeks, PDRN increased the closure of foot ulcers in diabetic subjects (hazard ratio 2.20; 95% CI 1.29-3.75; P = .004). The median time to complete wound healing was 49 days for placebo (range 28-56 d) and 30 days for PDRN-treated subjects (range 14-56 d; P = .0027). The median epithelialized area of the ulcers (expressed as percentage) was 49.3% in the placebo and 82.2% in the PDRN group (P < .001).

CONCLUSIONS

PDRN facilitates the healing of Wagner 1 or 2 diabetic foot ulcers.

Relaxin improves multiple markers of wound healing and ameliorates the disturbed healing pattern of genetically diabetic mice

Diabetic mice are characterized by a disrupted expression pattern of VEGF (vascular endothelial growth factor), and impaired vasculogenesis during healing. Experimental evidence suggests that RLX (relaxin) can improve several parameters associated with wound healing. Therefore we investigated the effects of porcine-derived RLX in diabetes-related wound-healing defects in genetically diabetic mice. An incisional wound model was produced on the back of female diabetic C57BL/KsJ-m+/+Lept(db) (db+/db+) mice and their normal littermates (db(+/+)m). Animals were treated daily with porcine RLX (25 μg/mouse per day, subcutaneously) or its vehicle. Mice were killed on 3, 6 and 12 days after skin injury for measurements of VEGF mRNA and protein synthesis, SDF-1α (stromal cell-derived factor-1α) mRNA and eNOS (endothelial NO synthase) expression. Furthermore, we evaluated wound-breaking strength, histological changes, angiogenesis and vasculogenesis at day 12. Diabetic animals showed a reduced expression of VEGF, eNOS and SDF-1α compared with non-diabetic animals. At day 6, RLX administration resulted in an increase in VEGF mRNA expression and protein wound content, in eNOS expression and in SDF-1α mRNA. Furthermore, the histological evaluation indicated that RLX improved the impaired wound healing, enhanced the staining of MMP-11 (matrix metalloproteinase-11) and increased wound-breaking strength at day 12 in diabetic mice. Immunohistochemistry showed that RLX in diabetic animals augmented new vessel formation by stimulating both angiogenesis and vasculogenesis. RLX significantly reduced the time to complete skin normalization and this effect was abrogated by a concomitant treatment with antibodies against VEGF and CXCR4 (CXC chemokine receptor 4), the SDF-1α receptor. These data strongly suggest that RLX may have a potential application in diabetes-related wound disorders.

Purinergic signalling and diabetes

The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes type 1 and 2, and possibly pancreatogenic diabetes, is rising globally. Events leading to insulin secretion and action are complex, but there is emerging evidence that intracellular nucleotides and nucleotides are not only important as intracellular energy molecules but also as extracellular signalling molecules in purinergic signalling cascades. This signalling takes place at the level of the pancreas, where the close apposition of various cells-endocrine, exocrine, stromal and immune cells-contributes to the integrated function. Following an introduction to diabetes, the pancreas and purinergic signalling, we will focus on the role of purinergic signalling and its changes associated with diabetes in the pancreas and selected tissues/organ systems affected by hyperglycaemia and other stress molecules of diabetes. Since this is the first review of this kind, a comprehensive historical angle is taken, and common and divergent roles of receptors for nucleotides and nucleosides in different organ systems will be given. This integrated picture will aid our understanding of the challenges of the potential and currently used drugs targeted to specific organ/cells or disorders associated with diabetes.

The effects of polydeoxyribonucleotide on the survival of random pattern skin flaps in rats

Background

Partial or complete necrosis of a skin flap is a common problem. Polydeoxyribonucleotide (PDRN) can be extracted from trout sperm and used as a tissue repair agent. The aim of this study was to investigate whether PDRN could improve the survival of random pattern skin flaps in rats.

Methods

Twenty-two male Sprague-Dawley rats were randomly divided into two groups: the PDRN treatment group (n=11) and the control group (n=11). Caudally pedicled random pattern skin flaps were elevated on their dorsal skin and resutured. The treatment group received daily intraperitoneal administration of PDRN (8 mg/kg/day), and the control group received fluid vehicle (NaCl 0.9%, 8 mg/kg/day) from day 0 to day 6. On day 7, the flap survival was evaluated and the harvested tissue surrounding the demarcation line of the necrotic area was stained with H&E, anti-rat vascular endothelial cell growth factor (VEGF) antibody, and PECAM-1/CD31 antibody.

Results

The average necrotic area of the flap in the PDRN group was significantly smaller when compared with that of the control group. Histologic and immunohistochemical evaluation showed that granulation thickness score and VEGF-positive staining cells were marked higher in the PDRN group than in the control group. PECAM-1/CD31-positive microvascular densities were significantly higher in the PDRN group when compared with the control group.

Conclusions

This study confirms that PDRN improves the survival of random pattern skin flaps in rats. These results may represent a new therapeutic approach to enhancing flap viability and achieving faster wound repair.

Adenosine A2A receptor-dependent proliferation of pulmonary endothelial cells is mediated through calcium mobilization, PI3-kinase and ERK1/2 pathways

Hypoxia and HIF-2α-dependent A2A receptor expression and activation increase proliferation of human lung microvascular endothelial cells (HLMVECs). This study was undertaken to investigate the signaling mechanisms that mediate the proliferative effects of A2A receptor. A2A receptor-mediated proliferation of HLMVECs was inhibited by intracellular calcium chelation, and by specific inhibitors of ERK1/2 and PI3-kinase (PI3K). The adenosine A2A receptor agonist CGS21680 caused intracellular calcium mobilization in controls and, to a greater extent, in A2A receptor-overexpressing HLMVECs. Adenoviral-mediated A2A receptor overexpression as well as receptor activation by CGS21680 caused increased PI3K activity and Akt phosphorylation. Cells overexpressing A2A receptor also manifested enhanced ERK1/2 phosphorylation upon CGS21680 treatment. A2A receptor activation also caused enhanced cAMP production. Likewise, treatment with 8Br-cAMP increased PI3K activity. Hence A2A receptor-mediated cAMP production and PI3K and Akt phosphorylation are potential mediators of the A2A-mediated proliferative response of HLMVECs. Cytosolic calcium mobilization and ERK1/2 phosphorylation are other critical effectors of HLMVEC proliferation and growth. These studies underscore the importance of adenosine A2A receptor in activation of survival and proliferative pathways in pulmonary endothelial cells that are mediated through PI3K/Akt and ERK1/2 pathways.

Systemic administration of high-molecular weight hyaluronan stimulates wound healing in genetically diabetic mice

Hyaluronic acid (HA), an essential component of the extracellular matrix, is an efficient space filler that maintains hydration, serves as a substrate for assembly of proteoglycans and is involved in wound healing. Although numerous pieces of evidence demonstrate beneficial effects in promoting wound healing in diabetes, a systemic approach has never been tested. We used an incisional wound healing model in genetically diabetic mice to test the effects of systemic injection of HA. Diabetic (n=56) and normoglycemic (n=56) mice were subjected to incision and randomized (8 groups of 7 animals each) to receive HA at different doses, 7.5, 15 and 30mg/kg/i.p., or vehicle (0.9% NaCl solution) for 12days. At the end of the experiment animals were sacrificed and skin wounds were excised for histological, biochemical and molecular analysis. Histology revealed that the most effective dose to improve wound repair and angiogenesis in diabetic mice was 30mg/kg. Furthermore HA injection (30mg/kg) improved the altered healing pattern in diabetic animals, increased skin remodeling proteins TGF-β and transglutaminase-II and restored the altered expression of cyclin B1/Cdc2 complex. Evaluation of skin from diabetic animals injected with HA revealed also an increase in HA content, suggesting that systemic injection may be able to restore the reduced intracellular HA pool of diabetic mice. Finally HA markedly improved skin mechanical properties. These promising results, if confirmed in a clinical setting, may improve the care and management of diabetic patients.