Polydeoxyribonucleotide (PDRN) restores blood flow in an experimental model of peripheral artery occlusive disease

Development and characterization of polydeoxyribonucleotide (PDRN) loaded chitosan polyplex: In vitro and in vivo evaluation of wound healing activity

Polydeoxyribonucleotide (PDRN) is an accelerated diabetic wound healing therapy with promising abilities to promote cell growth, angiogenesis, collagen synthesis, and reduce inflammation where its sustainable delivery and release behavior is critical to ensure effective wound healing properties. Therefore, a nanopolyplex was developed here, by encapsulating PDRN with chitosan to affirm its delivery systematically. The physicochemical characterization revealed its successful encapsulation which facilitates the gradual release of PDRN. In vitro studies of the polyplex demonstrated no cytotoxicity and enhanced cell proliferation and migration properties with high antimicrobial activities. In vivo, wound healing studies in Wistar rats dorsal skin defect model induced with diabetes mellitus affirm the highest wound healing activity and wound closure rate by chitosan/PDRN polyplex treatment. Considerably high histopathological changes such as epithelialization, collagen deposition, blood vessels, and hair follicle formation were observed under the polyplex treatment. The immunohistochemical analysis for platelet endothelial cell adhesion molecule (CD31) and cluster of differentiation (CD68) revealed the ability of polyplex to increase CD31 expression and decrease CD68 expression thereby promoting the wound healing process. Collectively, these results suggest that significantly accelerated, high-quality wound healing effects could be obtained by the developed chitosan/PDRN polyplex and thus it could be introduced as a potential therapeutic product for diabetic wound healing.

Targeting Adenosine Signalling in Knee Chondropathy: The Combined Action of Polydeoxyribonucleotide and Pulsed Electromagnetic Fields: A Current Concept Review

Chondropathy of the knee is one of the most frequent degenerative cartilage pathologies with advancing age. Scientific research has, in recent years, advanced new therapies that target adenosine A2 receptors, which play a significant role in human health against many disease states by activating different protective effects against cell sufferance and damage. Among these, it has been observed that intra-articular injections of polydeoxyribonucleotides (PDRN) and Pulsed Electromagnetic Fields (PEMF) can stimulate the adenosine signal, with significant regenerative and healing effects. This review aims to depict the role and therapeutic modulation of A2A receptors in knee chondropathy. Sixty articles aimed at providing data for our study were included in this review. The present paper highlights how intra-articular injections of PDRN create beneficial effects by reducing pain and improving functional clinical scores, thanks to their anti-inflammatory action and the important healing and regenerating power of the stimulation of cell growth, production of collagen, and the extracellular matrix. PEMF therapy is a valid option in the conservative treatment of different articular pathologies, including early OA, patellofemoral pain syndrome, spontaneous osteonecrosis of the knee (SONK), and in athletes. PEMF could also be used as a supporting therapy after an arthroscopic knee procedure total knee arthroplasty to reduce the post-operative inflammatory state. The proposal of new therapeutic approaches capable of targeting the adenosine signal, such as the intra-articular injection of PDRN and the use of PEMF, has shown excellent beneficial results compared to conventional treatments. These are presented as an extra weapon in the fight against knee chondropathy.

The impact of polydeoxyribonucleotide on early bone formation in lateral-window sinus floor elevation with simultaneous implant placement

PURPOSE

The aim of this study was to evaluate the impact of polydeoxyribonucleotide (PDRN) on histologic outcomes when implant placement and lateral sinus floor elevation are performed simultaneously.

METHODS

Three bimaxillary premolars (P2, P3, and P4) were extracted from 4 beagle dogs 2 months before lateral sinus floor elevation. After lateral elevation of the sinus membrane, each sinus was allocated to either the test or control group. Sinuses underwent either 1) collagenated synthetic bone graft with PDRN following lateral sinus floor elevation (test group) or 2) collagenated synthetic bone graft without PDRN after lateral sinus floor elevation (control group). Eight weeks after the surgical procedure, all animals were euthanised for a histologic and histomorphometric assessment. Augmented height (AH), protruding height (PH), and bone-to-implant contact in pristine (BIC_p) and augmented (BIC_a) bone were measured. The composition of the augmented area, which was divided into 3 areas of interest located in coronal, middle and apical areas (AOI_C, AOI_M, and AOI_A), was calculated with 3 parameters: the area percentage of new bone (pNB), residual bone graft particle (pRBP), and fibrovascular connective tissue (pFVT).

RESULTS

AH, PH, BIC_p, BIC_a total, BIC_a coronal, and BIC_a middle values were not significantly different between sinuses in the control and test groups (all P>0.05). The BIC_a apical of sinuses in the test group (76.7%±9.3%) showed statistically higher values than those of sinuses in the control group (55.6%±22.1%) (P=0.038). pNB, pRBP, and pFVT showed statistically significant differences between the 2 groups in AOI_A (P=0.038, P=0.028, and P=0.007, respectively). pNB, pRBP, and pFVT in AOI_C and AOI_M were not significantly different between samples in the control and test groups (all P>0.05).

CONCLUSIONS

The histologic findings revealed that lateral sinus floor elevation with PDRN might improve early new bone formation and enable higher bone-to-implant contact.

Polydeoxyribonucleotide in the Treatment of Tendon Disorders, from Basic Science to Clinical Practice: A Systematic Review

Polydeoxyribonucleotide (PDRN) is a proprietary and registered drug with several beneficial effects, including tissue repairing, anti-ischemic action, and anti-inflammatory properties. The present study aims to summarize the current evidence about PRDN's clinical effectiveness in the management of tendon disorders. From January 2015 to November 2022, OVID-MEDLINE^®, EMBASE, Cochrane Library, SCOPUS, Web of Science, Google Scholar and PubMed were searched to identify relevant studies. The methodological quality of the studies was evaluated, and relevant data were extracted. Nine studies (two in vivo studies and seven clinical studies) were finally included in this systematic review. Overall, 169 patients (male: 103) were included in the present study. The effectiveness and safeness of PDRN has been investigated in the management of the following diseases: plantar fasciitis; epicondylitis; Achilles tendinopathy; pes anserine bursitis; chronic rotator cuff disease. No adverse effects have been recorded in the included studies and all the patients showed an improvement in clinical symptoms during the follow-up. PDRN are a valid emerging therapeutic drug in the treatment of tendinopathies. Further multicentric randomized clinical studies are needed to better define the therapeutic role of PDRN, especially in combined clinical protocols.

Nanocomplexes of doxorubicin and DNA fragments for efficient and safe cancer chemotherapy

Cancer-targeted therapy by a chemotherapeutic agent formulated in a nanoscale platform has been challenged by complex and inefficient manufacturing, low drug loading, difficult characterization, and marginally improved therapeutic efficacy. This study investigated facile-to-produce nanocomplexes of doxorubicin (DOX), a widely used cancer drug, and clinically approved DNA fragments that are extracted from a natural source. DOX was found to self-assemble DNA fragments into relatively monodispersed nanocomplexes with a diameter of ∼70 nm at 14.3% (w/w) drug loading by simple and scalable mixing. The resulting DOX/DNA nanocomplexes showed sustained DOX release, unlike overly stable Doxil®, cellular uptake via multiple endocytosis pathways, and high hematological and immunological compatibility. DOX/DNA nanocomplexes eradicated EL4 T lymphoma cells in a time-dependent manner, eventually surpassing free DOX. Extended circulation of DOX/DNA nanocomplexes, while avoiding off-target accumulation in the lung and being cleared from the liver, resulted in rapid accumulation in tumor and lowered cardio toxicity. Finally, tumor growth of EL4-challenged C57BL/6 mice (syngeneic model) and OPM2-challenged NSG mice (human xenograft model) were efficiently inhibited by DOX/DNA nanocomplexes with enhanced overall survival, in comparison with free DOX and Doxil®, especially upon repeated administrations. DOX/DNA nanocomplexes are a promising chemotherapeutics delivery platform for their ease of manufacturing, high biocompatibility, desired drug release and accumulation, efficient tumor eradication with improved safety, and further engineering versatility for extended therapeutic applications.

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.

Effect of epidural polydeoxyribonucleotide in a rat model of lumbar foraminal stenosis

Background

We aimed to investigate the effect of epidural polydeoxyribonucleotide (PDRN) on mechanical allodynia and motor dysfunction in a rat model of lumbar foraminal stenosis (LFS).

Methods

This study was conducted in two stages, using male Sprague-Dawley rats. The rats were randomly divided into eight groups. In the first stage, the groups were as follows vehicle (V), sham (S), and epidural PDRN at 5 (P5), 8 (P8), and 10 (P10) mg/kg; and in the second stage, they were as follows intraperitoneal PDRN 8 mg/kg, epidural 3,7-dimethyl-1-propargilxanthine (DMPX) (0.1 mg/kg), and DMPX (0.1 mg/kg). The LFS model was established, except for the S group. After an epidural injection of the test solutions, von Frey and treadmill tests were conducted for 3 weeks. Subsequently, histopathologic examinations were conducted in the V, S, P5, and P10 groups.

Results

A total of 65 rats were included. The P8 and P10 groups showed significant recovery from mechanical allodynia and motor dysfunction at all time points after drug administration compared to the V group. These effects were abolished by concomitant administration of DMPX. On histopathological examination, no epineurial inflammation or fibrosis was observed in the epidural PDRN groups.

Conclusions

Epidural injection of PDRN significantly improves mechanical allodynia and motor dysfunction in a rat model of LFS, which is mediated by the spinal adenosine A_2A receptor. The present data support the need for further research to determine the role of epidural PDRN in spinal stenosis treatment.

Eradication of Intracellular Salmonella Typhimurium by Polyplexes of Acid-Transforming Chitosan and Fragment DNA

Antibiotics are highly successful against microbial infections. However, current challenges include rising antibiotic resistance rates and limited efficacy against intracellular pathogens. A novel form of a nanomaterial-based antimicrobial agent is investigated for efficient treatment of an intracellular Salmonella enterica sv Typhimurium infection. A known antimicrobial polysaccharide, chitosan, is engineered to be readily soluble under neutral aqueous conditions for systemic administration. The modified biologic, named acid-transforming chitosan (ATC), transforms into an insoluble, antimicrobial compound in the mildly acidic intracellular compartment. In cell culture experiments, ATC is confirmed to have antimicrobial activity against intracellular S. Typhimurium in a concentration- and pH-dependent manner, without affecting the host cells, RAW264.7 macrophages. For improved cellular uptake and pharmacokinetic/pharmacodynamic properties, ATC is further complexed with fragment DNA (fDNA), to form nano-sized spherical polyplexes. The resulting ATC/fDNA polyplexes efficiently eradicated S. Typhimurium from RAW264.7 macrophages. ATC/fDNA polyplexes may bind with microbial wall and membrane components. Consistent with this expectation, transposon insertion sequencing of a complex random mutant S. Typhimurium library incubated with ATC does not reveal specific genomic target regions of the antimicrobial. This study demonstrates the utility of a molecularly engineered nanomaterial as an efficient and safe antimicrobial agent, particularly against an intracellular pathogen.

Sympathetic Nerve Control of Blood Pressure Response during Exercise in Peripheral Artery Disease and Current Application of Experimental Disease Models

In patients with peripheral artery disease (PAD), the blood supply directed to the lower limbs is reduced. This results in severe limb ischemia and thereby intermittent claudicating which is characterized by pain in lower limbs that occurs with walking and is relieved by rest. Of note, PAD can extremely affect the quality of living of patients and increase high risk of coronary and cerebral vascular accidents. However, effective treatments of PAD are still challenging in clinics. A number of reports have demonstrated the beneficial effects of supervised exercise on symptoms of PAD patients. This review will summarize results obtained from recent human and animal studies, which include the abnormalities in sympathetic control of blood pressure response during exercise in PAD, and rationality of animal models used for study human PAD. Nonetheless, additional in-depth studies are necessary to better explore the underlying mechanisms of the exaggerated responses of sympathetic nerve and blood pressure in PAD at molecular and cellular levels.

Anti-Allodynic Effects of Polydeoxyribonucleotide in an Animal Model of Neuropathic Pain and Complex Regional Pain Syndrome

BACKGROUND

Spinal nerve ligation (SNL) model is one of the representative models of the neuropathic pain model. Neuropathic pain in a chronic post-ischemic pain (CPIP) mimics the symptoms of complex regional pain syndrome (CRPS). The administration of polydeoxyribonucleotide (PDRN), which has regenerative and anti-inflammatory effects, has been studied and is used in clinical practice treating various diseases. However, the analgesic effect of PDRN in a neuropathic pain or CRPS model remains unknown.

METHODS

PDRN (3.3, 10, and 20 mg/kg) was administered into the subcutaneous (SC) layer of the hind paws of SNL and CPIP models. Mechanical anti-allodynic effects were then investigated using the von Frey test. In the immunohistochemical examination, dorsal root ganglia (DRG) and the spinal cord were harvested and examined for the expression of glial fibrillary acidic protein (GFAP) after the 20 mg PDRN injection.

RESULTS

Mechanical allodynia was significantly alleviated by administration of PDRN in SNL and CPIP mice at all of the time point. As the dose of PDRN increased, the effect was greater. The 20 mg PDRN injection was found to have the most effective anti-allodynic effect. The increased expression of GFAP in DRG and the spinal cord of SNL and CPIP model decreased following the administration of PDRN than vehicle.

CONCLUSION

SC administration of PDRN results in the attenuation of allodynia and activation of astrocytes in neuropathic pain or CRPS models. We propose that PDRN can have significant potential advantages in neuropathic pain treatment.

Polydeoxyribonucleotide Exerts Therapeutic Effect by Increasing VEGF and Inhibiting Inflammatory Cytokines in Ischemic Colitis Rats

Ischemic colitis is resulted from an inadequate blood supply to a segment or entire colon. Polydeoxyribonucleotide (PDRN), extracted from salmon sperm, has been reported to exert anti-inflammatory and anti-ischemic effects through the adenosine A_2A receptor (A_2AR). We investigated whether PDRN possesses therapeutic effectiveness on ischemic colitis rats. Ischemic colitis was induced by selective devascularization. The skin temperature on the ischemic colitis-induced region was determined. To assess the colonic damage score and collagen deposition, colonic tissue sections were stained with hematoxylin and eosin (H&E), and Masson trichrome staining was performed. Western blot analysis for A_2AR, vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6, Bax, Bcl-2, and extracellular signal-regulated kinase 1/2 (ERK1/2) was performed. Skin temperature was increased and mucosal damage and collagen deposition were observed in the affected colonic tissues in the ischemic colitis rats. Expressions of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and inflammatory mediator (COX-2) were upregulated in the ischemic colitis rats. Apoptosis was increased by decreasing the ratio of Bcl-2 to Bax and by suppressing the phosphorylated form of ERK1/2 expression in the ischemic colitis rats. Treatment with PDRN alleviated mucosal damage reduced the expressions of inflammatory cytokines and COX-2 and inhibited apoptosis in the ischemic colitis rats. PDRN treatment more enhanced the expressions of A_2AR and VEGF in the ischemic colitis rats. PDRN showed therapeutic effectiveness on ischemic colitis by increasing VEGF expression and inhibiting inflammatory cytokines and COX-2 through enhancing A_2AR expression.

Polydeoxyribonucleotide Activates Mitochondrial Biogenesis but Reduces MMP-1 Activity and Melanin Biosynthesis in Cultured Skin Cells

The regulation of mitochondrial biogenesis, melanogenesis, and connective tissue proteins is critical for homeostasis and aging skin cells. We examined the biological effects of polydeoxyribonucleotide (PDRN) on mitochondrial biogenesis, melanogenesis, and connective tissue proteins in vitro. In a radical scavenging assay, PDRN showed antioxidant activities in a dose-dependent manner, and those activities can suppress cellular oxidative stress in skin cells. PDRN directly inhibited mushroom tyrosinase activity and cellular tyrosinase activity, thus significantly reducing the cellular melanin content in B16-F10 melanocytes. The mRNA and protein expressions of the microphthalmia-associated transcription factor (MITF), which is a key melanogenic gene transcription factor, were significantly downregulated by PDRN. Accordingly, tyrosinase-related protein 1, dopachrome tautomerase, and tyrosinase, which gene expressions were regulated by MITF, were significantly downregulated by PDRN. Mitotracker-probed mitochondria image analysis suggested that PDRN enhanced mitochondrial density in both murine melanoma cells and in human skin fibroblast cells. In addition, PDRN strongly suppressed in vitro elastase enzyme activity in a dose-dependent manner and inhibited matrix metalloproteinase-1 gene expression in human skin fibroblast cells. Collectively, these findings indicate that PDRN has multiple beneficial biological activities in skin cells: hypopigmentation, induction of mitochondrial biogenesis, and the inhibition of collective tissue proteins.

Effect of Polydeoxyribonucleotide on Chondrocutaneous Composite Grafts Survival

BACKGROUND

A composite graft is considered the best choice for facial reconstruction because of proper texture, color, and simple surgical techniques. However, due to revascularization by the bridging phenomenon, it has limitations with unpredictable survival rates and can be applied only to small defects. Polydeoxyribonucleotide (PDRN) plays an important role in multiple vascular processes such as angiogenesis via production of a vascular endothelial growth factor and by providing an anti-inflammatory effect by reducing pro-inflammatory cytokines through the adenosine A2 receptor stimulation. Thus, here, we investigated PDRN as a supportive method to improve survival of composite grafts.

METHODS

Chondrocutaneous composite grafts were applied to both ears of 20 New Zealand White rabbits. The grafts were then rotated and returned to their positions to prevent the original blood flow from the base of the grafts. On postoperative days 1, 3, 6, 9, and 12, PDRN was injected intradermally into the experimental group (20 ears) and normal saline was injected into the control group (20 ears) to exclude bias of pressure effect. After 12 days, graft survival and cutaneous blood flow were examined under laser speckle contrast imaging.

RESULTS

Gross observation indicated that the graft viability in the PDRN group was significantly higher than that in the control group (p < 0.05). Through laser speckle contrast imaging, signal intensity increased from the periphery and progressed centrally with treatment.

CONCLUSION

Our findings suggest that PDRN may increase blood flow around at the base of the graft, restore the perfusion, and improve the survival of the composite grafts.

NO LEVEL ASSIGNED

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

The efficacy and safety of BM-PHA for the correction of nasolabial folds: a multicenter, randomized, double-blind, split-face clinical trial

Background: Multiple types of fillers have been developed for soft tissue augmentation.Objective: We investigated the efficacy and safety of the novel filler BM-PHA.Methods: In this multicenter, randomized, split-face study, 91 participants received injections of BM-PHA and Restylane Perlane (PER) into the nasolabial folds. Efficacy was determined by the improvements in the Wrinkle Severity Rating Score (WSRS) and Global Esthetic Improvement Scale (GAIS), and safety by adverse events, laboratory tests, and a check of vital signs.Results: WSRS scores assessed by independent evaluators at Week 24, the primary efficacy measure, showed no significant difference between the two treatments. The treatments also showed no significant differences in WSRS scores assessed by the evaluators at Week 8 and WSRS and GAIS scores assessed by the treating investigators and participants at Weeks 8 and 24. The proportion of nasolabial folds whose WSRS scores improved by at least one grade at Week 24 was similar between the treatments. Only minor local side effects were reported without sequelae.Conclusion: BM-PHA was not inferior to PER in the treatment of moderate to severe nasolabial folds and may be an appropriate alternative product for their improvement. Further studies are needed to confirm the long-term safety of BM-PHA.

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.

The Effect of Polydeoxyribonucleotide on Chronic Non-healing Wound of an Amputee: A Case Report

Polydeoxyribonucleotide (PDRN) is safe and effective in wound healing, cellular growth, synthesis of extracellular matrix protein, and inflammation reduction via activation of adenosine A2 receptors. We report a 28-year-old male patient treated with PDRN injections for chronic non-healing wound refractory to negative pressure wound therapy, skin graft, or growth factors. Three injections of PDRN were administered at the wound site into the anterior and medial sides of the left stump on the 1st, 4th, and 9th days of hospitalization. The PDRN ameliorated wound healing by enhancing cell growth, tissue repair, and angiogenesis. PDRN application represents a potential treatment for non-healing wounds obviating the need for additional therapies, and hospitalization, as well as improve patient’s activities of daily living.

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.

Treatment of Full-Thickness Rotator Cuff Tendon Tear Using Umbilical Cord Blood-Derived Mesenchymal Stem Cells and Polydeoxyribonucleotides in a Rabbit Model

Objective

The aim of this study was to investigate regenerative effects of ultrasound- (US-) guided injection with human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) and/or polydeoxyribonucleotide (PDRN) injection in a chronic traumatic full-thickness rotator cuff tendon tear (FTRCTT) in a rabbit model.

Methods

Rabbits (n = 32) were allocated into 4 groups. After a 5 mm sized FTRCTT just proximal to the insertion site on the subscapularis tendon was created by excision, the wound was immediately covered by a silicone tube to prevent natural healing. After 6 weeks, 4 injectants (0.2 mL normal saline, G1-SAL; 0.2 mL PDRN, G2-PDRN; 0.2 mL UCB-MSCs, G3-MSC; and 0.2 mL UCB-MSCs with 0.2 ml PDRN, G4-MSC + PDRN) were injected into the FTRCTT under US guidance. We evaluated gross morphologic changes on all rabbits after sacrifice. Masson's trichrome, anti-type 1 collagen antibody, bromodeoxyuridine, proliferating cell nuclear antigen, vascular endothelial growth factor, and platelet endothelial cell adhesion molecule stain were performed to evaluate histological changes. Motion analysis was also performed.

Results

The gross morphologic mean tendon tear size in G3-MSC and G4-MSC + PDRN was significantly smaller than that in G1-SAL and G2-PDRN (p < 0.05). However, there were no significant differences in the tendon tear size between G3-MSC and G4-MSC + PDRN. In G4-MSC + PDRN, newly regenerated collagen type 1 fibers, proliferating cell activity, angiogenesis, walking distance, fast walking time, and mean walking speed were greater than those in the other three groups on histological examination and motion analysis.

Conclusions

Coinjection of UCB-MSCs and PDRN was more effective than UCB-MSC injection alone in histological and motion analysis in a rabbit model of chronic traumatic FTRCTT. However, there was no significant difference in gross morphologic change of tendon tear between UCB-MSCs with/without PDRN injection. The results of this study regarding the combination of UCB-MSCs and PDRN are worth additional investigations.

Ultrasound-Guided Prolotherapy with Polydeoxyribonucleotide for Painful Rotator Cuff Tendinopathy

Background

Rotator cuff tendinopathy is a primary cause of shoulder pain and dysfunction. Several effective nonsurgical treatment methods have been described for chronic rotator cuff tendinopathy. Prolotherapy with polydeoxyribonucleotide (PDRN), which consists of active deoxyribonucleotide polymers that stimulate tissue repair, is a nonsurgical regenerative injection that may be a viable treatment option. The objective of this study was to assess the efficacy of PDRN in the treatment of chronic rotator cuff tendinopathy.

Method

The records of patients with chronic rotator cuff tendinopathy (n=131) were reviewed retrospectively, and the patients treated with PDRN prolotherapy (n=32) were selected. We measured the main outcome of the shoulder pain and disability index score on a numerical rating scale of average shoulder pain.

Results

Compared with baseline data, significant improvements in the shoulder pain and disability index and pain visual analog scale scores were demonstrated at one week after the end of treatment, and at one month and three months later.

Conclusions

PDRN prolotherapy may improve the conservative treatment of painful rotator cuff tendinopathy for a specific subset of patients.

Comparison of wound healing effects between Oncorhynchus keta-derived polydeoxyribonucleotide (PDRN) and Oncorhynchus mykiss-derived PDRN

Background

Polydeoxyribonucleotide (PDRN) influencing cellular growth and differentiation is recognized to promote wound healing by stimulating tissue repair. Although PDRN can be extracted from human placentas, PDRN medications have recently been extracted from the semen of trout (Oncorhynchus mykiss) and salmon (Oncorhynchus keta). The present study was designed to evaluate the wound healing effects of O. keta-derived PDRN for injection (Rejuvenex) and PDRN cream (Rejuvenex Cream) in comparison with those of O. mykiss-derived PDRN injection (Placentex).

Methods

Full-thickness skin defects were made on the back of mice (n=60). The mice were divided into the following four groups according to the dressing used for the wounds: O. mykiss-derived PDRN injection group, O. keta-derived PDRN injection group, O. keta-derived PDRN cream group, and normal saline soaked dressing group (control group). We analyzed the gross findings, wound sizes, histological findings, immunohistochemistry and enzyme-linked immunosorbent assays for the groups immediately after the treatment, and again after 4, 7, and 10 days of treatment.

Results

The wound healing effects were the greatest in the O. keta-derived PDRN injection and O. mykiss-derived PDRN injection groups, which showed similar scores, followed by the O. keta-derived cream and normal saline soaked dressing groups.

Conclusion

The injection of PDRN extracted from O. keta was found to be as effective at healing full-thickness skin defects as the O. mykiss-derived PDRN injection, which is currently used in the clinic. Moreover, the O. keta-derived PDRN injection was also found to reduce the time required for wound healing.

Effects of salmon DNA fraction in vitro and in a monosodium iodoacetate-induced osteoarthritis rat model

PRF001 is a fragmented DNA polymer extracted from the testes of salmon. The purpose of this study was to assess the anti-inflammatory effect of PRF001 in vitro as well as the protective effect of PRF001 intake against arthritis in a rat model. In vitro, cell survival and inflammatory markers after H₂O₂ treatment to induce cell damage were investigated in CHON-001 cells treated with different concentrations of PRF001. In vivo, osteoarthritis was induced by intra-articular injection of monosodium iodoacetate (MIA) into the knee joints of rats. After consumption of PRF001 (10, 50, or 100 mg/kg) for 4 weeks, inflammatory mediators and cytokines in articular cartilage were investigated. In vitro, the levels of inflammatory markers, IL-1β, TNF-α, COX-2, iNOS, and PGE2, were significantly suppressed by PRF001 treatment. In vivo, the inflammatory mediators and cytokines, IL-1β, p-Erk1/2, NF-κB, TNF-α, COX-2, and PGE2, as well as MMP3 and MMP7, which have catabolic activity in chondrocytes, were decreased in the MIA-induced osteoarthritic rats following intake of PRF001. Histological analysis revealed that PRF001 had a protective effect on the articular cartilage. Altogether, these results demonstrated that the anti-inflammatory property of PRF001 contributes to its protective effects in osteoarthritis through deregulating IL-1β, TNF-α, and subsequent signals, such as p-Erk1/2, NF-κB, COX-2, PGE2, and MMPs.

Polydeoxyribonucleotide Improves Peripheral Tissue Oxygenation and Accelerates Angiogenesis in Diabetic Foot Ulcers

BACKGROUND

Polydeoxyribonucleotide (PDRN) is known to have anti-inflammatory and angiogenic effects and to accelerate wound healing. The aim of this study was to investigate whether PDRN could improve peripheral tissue oxygenation and angiogenesis in diabetic foot ulcers.

METHODS

This was a prospective randomized controlled clinical trial. Twenty patients with a non-healing diabetic foot ulcer were randomly distributed into a control group (n=10) and a PDRN group (n=10). Initial surgical debridement and secondary surgical procedures such as a split-thickness skin graft, primary closure, or local flap were performed. Between the initial surgical debridement and secondary surgical procedures, 0.9% normal saline (3 mL) or PDRN was injected for 2 weeks by the intramuscular (1 ampule, 3 mL, 5.625 mg, 5 days per week) and perilesional routes (1 ampule, 3 mL, 5.625 mg, 2 days per week). Transcutaneous oxygen tension (TcPO₂) was evaluated using the Periflux System 5000 with TcPO₂/CO₂ unit 5040 before the injections and on days 1, 3, 7, 14, and 28 after the start of the injections. A pathologic review (hematoxylin and eosin stain) of the debrided specimens was conducted by a pathologist, and vessel density (average number of vessels per visual field) was calculated.

RESULTS

Compared with the control group, the PDRN-treated group showed improvements in peripheral tissue oxygenation on day 7 (P<0.01), day 14 (P<0.001), and day 28 (P<0.001). The pathologic review of the specimens from the PDRN group showed increased angiogenesis and improved inflammation compared with the control group. No statistically significant difference was found between the control group and the PDRN group in terms of vessel density (P=0.094). Complete healing was achieved in every patient.

CONCLUSIONS

In this study, PDRN improved peripheral tissue oxygenation. Moreover, PDRN is thought to be effective in improving inflammation and angiogenesis in diabetic foot ulcers.

Sodium-DNA for Bone Tissue Regeneration: An Experimental Study in Rat Calvaria

Surgical techniques in dental and maxillofacial surgery request fast bone tissue regeneration, so there is a significant need to improve therapy for bone regeneration. Several studies have recently underlined the importance of nucleotides and nucleosides to increase cell proliferation and activity; in particular, the ability of polydeoxyribonucleotide (PDRN) to induce growth and activity of human osteoblasts was demonstrated. Sodium-DNA is the deoxyribonucleic acid (DNA) extracted from the gonadic tissue of male sturgeon and then purified, depolymerized, and neutralized with sodium hydroxide. To date, there are no evidences about the use of Sodium-DNA for bone tissue regeneration. Consequently, our question is about the efficacy of Sodium-DNA in bone healing. For testing the role of Sodium-DNA in bone healing we used a rat calvarial defect model. Sodium-DNA at different concentrations used alone or in association with Fibrin and/or Bio-Oss was used for healing treatments and the bone healing process was evaluated by histomorphometric and immunohistochemical analyses. Our results suggested a positive effect of Sodium-DNA in bone regeneration, providing a useful protocol and a model for the future clinical evaluation of its osteogenic properties.

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, an Adenosine-A2A Receptor Agonist, Preserves Blood Testis Barrier from Cadmium-Induced Injury

Cadmium (Cd) impairs blood-testis barrier (BTB). Polydeoxyribonucleotide (PDRN), an adenosine A_2A agonist, has positive effects on male reproductive system. We investigated the effects of PDRN on the morphological and functional changes induced by Cd in mice testes. Adult Swiss mice were divided into four groups: controls administered with 0.9% NaCl (1 ml/kg, i.p., daily) or with PDRN (8 mg/kg, i.p. daily), animals challenged with Cd chloride (CdCl₂; 2 mg/kg, i.p, daily) and animals challenged with CdCl₂ (2 mg/kg, i.p., daily) and treated with PDRN (8 mg/kg, i.p., daily). Experiments lasted 14 days. Testes were processed for biochemical, structural, and ultrastructural evaluation and hormones were assayed in serum. CdCl₂ increased pERK 1/2 expression and Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) levels; it decreased testosterone (TE) and inhibin-B levels and induced structural damages in extratubular compartment and in seminiferous epithelium, with ultrastructural features of BTB disruption. Many TUNEL-positive germ cells were present. CdCl₂ increased tubular TGF-β3 immunoreactivity and reduced claudin-11, occludin, and N-cadherin immunoreactivity. PDRN administration reduced pERK 1/2 expression, FSH, and LH levels; it increased TE and inhibin-B levels, ameliorated germinal epithelium changes and protected BTB ultrastructure. Few TUNEL-positive germ cells were present and the extratubular compartment was preserved. Furthermore, PDRN decreased TGF-β3 immunoreactivity and enhanced claudin-11, occludin, and N-cadherin immunoreactivity. We demonstrate a protective effect of PDRN on Cd-induced damages of BTB and suggest that PDRN may play an important role against Cd, particularly against its harmful effects on gametogenesis.

Protective Effect of Polydeoxyribonucleotide Against Renal Ischemia-Reperfusion Injury in Mice

BACKGROUND

Polydeoxyribonucleotide (PDRN) is an A2A receptor agonist that induces vascular endothelial growth factor (VEGF) production during the pathological condition of low tissue perfusion. Ischemia-reperfusion injury (IRI) is a major problem after renal transplantation. In the present study, we investigated whether PDRN exhibits reno-protective effects against ischemia-reperfusion-induced acute kidney injury in mice.

METHODS

Renal ischemia-reperfusion injury was induced in male C57BL/6 mice by bilateral renal pedicle occlusion for 30 minutes, followed by reperfusion for 48 hours. PDRN (8 mg/kg body weight intraperitoneally) was administered 30 minutes before IRI.

RESULTS

Treatment with PDRN significantly decreased neutrophil gelatinase-associated lipocalin levels in the urine, blood urea nitrogen level, and serum creatinine levels as well as kidney tubular injury. Western blotting showed that PDRN significantly increased the levels of vascular endothelial growth factor and B-cell lymphoma protein and attenuated p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, inducible nitric oxide synthase, and Bcl-2-associated X protein levels 48 hours after IRI.

CONCLUSIONS

Our findings suggest that PDRN is a potential therapeutic agent for acute ischemia-induced renal damage.

Polydeoxyribonucleotide improves wound healing of fractional laser resurfacing in rat model

BACKGROUND

Polydeoxyribonucleotide (PDRN) is an active compound that can promote wound healing. PDRN stimulates wound healing by enhancing angiogenesis and increasing fibroblast growth rates. Laser skin resurfacing is a popular cosmetic procedure for skin rejuvenation. Despite excellent improvement of photo-damaged skin and acne scarring, it is accompanied with drawbacks, such as prolonged erythema and crusting.

OBJECTIVE

This study was designed to assess the effect of PDRN on wounds induced by fractional laser resurfacing.

METHODS

Twelve male rats aged 8 weeks were randomly assigned to the PDRN treatment group and the control group. Wounds were induced using a fractional ablative CO₂ laser. The treatment group received daily injections of PDRN and the control group received injections of the vehicle. Wound healing assessed by clinical features and histopathologic findings.

RESULTS

The process of wound healing was faster in the treatment group than in the control group. In the histopathological examination, the granulation tissue thickness score of the treatment group was significantly higher than that of the control group. Results of immunohistochemical staining showed a marked increase of VEGF-positive cells and PECAM-1/CD31-positive microvessels in the treatment group.

CONCLUSION

PDRN may be a beneficial option to promote wound healing after laser treatment.

Effects of polydeoxyribonucleotides (PDRN) on wound healing: Electric cell-substrate impedance sensing (ECIS)

Polydeoxyribonucleotides (PDRN) have been explored as an effective treatment for tissue repair in peripheral artery occlusive disease, diabetic foot ulcers, and eye lotion. We report on the effect of polydeoxyribonucleotides (PDRN) on wound healing by using the electric cell-substrate impedance sensing (ECIS) system and viability testing. Human osteoblasts (U2OS) and primary human dermal fibroblasts (HDF) were used to study the effect of PDRN on migration and proliferation. ECIS allowed the creation of a wound by applying high current, and then monitoring the healing process by measuring impedance in real time. The traditional culture-insert gap-closure migration assay was performed and compared with the ECIS wound assay. PDRN-treated U2OS and HDF cells affected cell motilities to wounding site. Viability test results show that HDF and U2OS proliferation depended on PDRN concentration. Based on the results, a PDRN compound can be useful in wound healing associated with bone and skin.

The Effect of Polydeoxyribonucleotide on Ischemic Rat Skin Flap Survival

Polydeoxyribonucleotide (PDRN) has multiple vascular actions such as angiogenesis and production of a vascular endothelial growth factor (VEGF) through the adenosine A2 receptor stimulation. We applied PDRN on the ischemic flap of rat back and investigated whether it enhances the skin flap survival. A total of 28 Sprague-Dawley rats were divided into 3 groups, namely, PDRN group, control group 1 (no treatment), and group 2 (phosphate-buffered saline injection). On the distally based flap of 3 × 9 cm in size, it was subdermally injected with PDRN or phosphate-buffered saline, which were administered 48 hours prior and immediately after flap elevation. The PDRN group was daily maintained by intraperitoneal administration of PDRN from the postoperative 1st day to 10th day. The mean survival rates of flap in PDRN group [79.5% (6.3%)] are significantly larger than control groups [1, 53.0% (6.9%); 2, 51.7% (6.7%)]. Serial measurements of blood perfusion also showed that the blood flux was significantly increased in almost part of the flap on the 10 days after PDRN injection. The number of CD31 positively stained vessels and expression of VEGF protein were significantly higher in the PDRN group. We propose that administration of PDRN into the ischemic skin flaps increased blood flux to the flap, VEGF expression, and number of capillaries, thereby improving the rat skin flap survival.

Inhibition of Prostaglandin Transporter (PGT) Promotes Perfusion and Vascularization and Accelerates Wound Healing in Non-Diabetic and Diabetic Rats

Peripheral ischemia, resulting from diminished arterial flow and defective local vascularization, is one of the main causes of impaired wound healing in diabetes. Vasodilatory prostaglandins (PGs), including PGE₂ and PGI₂, regulate blood flow in peripheral tissues. PGs also stimulate angiogenesis by inducing vascular endothelial growth factor. However, PG levels are reduced in diabetes mainly due to enhanced degradation. We hypothesized that inhibition of the prostaglandin transporter (PGT) (SLCO2A1), which mediates the degradation of PGs, would increase blood flow and stimulate vascularization, thereby mitigating peripheral ischemia and accelerating wound healing in diabetes. Here we report that inhibiting PGT with intravenously injected PGT inhibitor, T26A, increased blood flow in ischemic hind limbs created in non-diabetic rats and streptozotocin induced diabetic rats. Systemic, or combined with topical, T26A accelerated closure of cutaneous wounds. Immunohistochemical examination revealed that inhibition of PGT enhanced vascularization (marked by larger numbers of vessels formed by CD34+ cells), and accelerated re-epithelialization of cutaneous wounds. In cultured primary human bone marrow CD34+ cells and human epidermal keratinocytes (HEKs) either inhibiting or silencing PGT increased migration in both cell lines. Thus PGT directly regulates mobilization of endothelial progenitor cells (EPCs) and HEKs, which could contribute to PGT-mediated vascularization and re-epithelialization. At the molecular level, systemic inhibition of PGT raised circulating PGE₂. Taken together, our data demonstrate that PGT modulates arterial blood flow, mobilization of EPCs and HEKs, and vascularization and epithelialization in wound healing by regulating vasodilatory and pro-angiogenic PGs.

Polyethylene glycol formulations show different soft tissue remodeling and angiogenesis features

BACKGROUND

Soft tissue regeneration and remodeling is fundamental in periodontal surgery, thus we investigated the angiogenic response elicited in the subcutaneous tissue of rats by a proprietary, polyethylene glycol hydrogel formulation (PEG) alone or conjugated with specific amelogenins (EMD) or nanobioglass particles (NBG).

METHODS

Discs with three different formulations (PEG, PEG-EMD, and PEG-NBG) were inserted into four unconnected subcutaneous pouches, produced on the back of Sprague-Dawley rats (n=56, divided into three groups), and used for blood flow evaluation by Laser Doppler analysis at 1, 2, 4, 8, and 16 weeks or for histological and immunohistochemical analysis at 1, 2, 4, 8, and 16 weeks.

RESULTS

All formulations showed tissue integration, absence of inflammatory reaction (as revealed by myeloperoxidase staining), and increased vascularization (by counting microvascular density following CD31 staining). Laser Doppler analysis revealed a statistically significant increase in blood flow after 1 week for PEG-EMD and after 2 weeks for PEG-NBG. The angiogenic response was significantly increased at 1, 2, and 8 weeks for PEG-EMD, but only at 4 weeks for PEG-NBG.

CONCLUSIONS

The studied biomaterials revealed equal biocompatibility and tissue integration properties. PEG-EMD showed the most pronounced and consistent angiogenic response in the early phases of wound healing, while the PEG-NBG formulation provided a slower and delayed, but relevant, response.

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.

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.

Polydeoxyribonucleotide restores blood flow in an experimental model of ischemic skin flaps

BACKGROUND

Ischemia is a major factor contributing to failure of skin flap surgery, which is routinely used for coverage of wounds to prevent infection and to restore form and function. An emerging concept is that adenosine A(2A) receptors can improve tissue oxygenation by stimulating angiogenesis, likely through vascular endothelial growth factor (VEGF). This study assessed the ability of polydeoxyribonucleotide (PDRN) to restore blood flow and improve wound healing, acting through the A(2A) receptor, in a rat model of ischemic skin flaps.

METHODS

The H-shaped double-flap model was used in male Sprague-Dawley rats. After surgical procedures, the animals were randomized to receive intraperitoneal PDRN (8 mg/kg) or vehicle (NaCl 0.9%). Rats were euthanized 3, 5, and 10 days after skin injury, after the evaluation of skin perfusion by laser Doppler. The wounds underwent histologic analysis and were measured for VEGF messenger RNA and protein expression, hypoxia inducible factor-1-α (HIF-1α), and inducible nitric oxide synthase (iNOS) protein expression, and nitrite content.

RESULTS

Blood flow markedly increased in blood flow in ischemic flaps treated with PDRN, with a complete recovery starting from day 5 (ischemic flap + vehicle, 1.80 ± 0.25; ischemic flap + PDRN, 2.46 ± 0.25; P < .001). Administration of PDRN enhanced the expression of VEGF (ischemic flap + vehicle, 5.3 ± 0.6; ischemic flap + PDRN, 6.2 ± 0.5; P < .01) at day 5, and iNOS (ischemic flap + vehicle, 3.9 ± 0.6; ischemic flap + PDRN, 5.3 ± 1; P < .01), but reduced HIF-1α expression (ischemic flap + vehicle, 7 ± 1.1; ischemic flap + PDRN, 4.8 ± 0.5; P < .05) at day 3. Histologically, the PDRN-treated group showed complete re-epithelialization and well-formed granulation tissue rich in fibroblasts.

CONCLUSIONS

These results suggest that PDRN restores blood flow and tissue architecture, probably by modulating HIF-1α and VEGF expression, and may be an effective therapeutic approach in improving healing of ischemic skin flaps.

Polydeoxyribonucleotide reduces cytokine production and the severity of collagen-induced arthritis by stimulation of adenosine A(₂A) receptor

OBJECTIVE

Broad antiinflammatory effects following adenosine A(₂A) receptor stimulation have been demonstrated in acute inflammatory diseases, including arthritis. Polydeoxyribonucleotide (PDRN) activates the adenosine A(₂A) receptor. This study was undertaken to investigate the effects of PDRN in collagen-induced arthritis (CIA) in mice.

METHODS

Arthritis was induced in DBA/1 mice by an intradermal injection of 100 μl of bovine type II collagen in Freund's complete adjuvant. Mice were immunized a second time 21 days later. Control animals received 100 μl of a saline solution. Animals with CIA were randomized to receive one of the following: vehicle (1 ml/kg); PDRN (8 mg/kg intraperitoneally daily); 3,7-dimethyl-propargylxanthine (DMPX), a specific adenosine A(₂A) receptor antagonist (0.1 mg/kg intraperitoneally daily); or PDRN plus DMPX. The treatment was initiated immediately after the second immunization and continued to day 45. Clinical evaluation of arthritis was performed throughout the study. On day 45, the animals were killed and the severity of arthritis was evaluated histologically. Cartilage expression and circulating levels of high mobility group box chromosomal protein 1 (HMGB-1), tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and IL-10 were investigated. Inflammatory cytokine production was also evaluated in stimulated human chondrocytes treated with PDRN.

RESULTS

PDRN treatment significantly ameliorated clinical signs of arthritis, improved histologic damage, reduced the cartilage expression and circulating levels of HMGB-1, TNFα, and IL-6, and enhanced IL-10 expression. The concomitant administration of DMPX and PDRN ablated the PDRN-induced protective effect in experimental arthritis. PDRN also reduced cytokine production from stimulated human chondrocytes.

CONCLUSION

Our findings indicate that PDRN may represent a new alternative for the treatment of arthritis.

Effects of polydeoxyribonucleotide on the histological damage and the altered spermatogenesis induced by testicular ischaemia and reperfusion in rats

The effects of polydeoxyribonucleotide (PDRN), an agonist of the A2A adenosine receptors which when activated positively influences sperm activity, were tested in an experimental testicular ischaemia/reperfusion injury model. Anaesthetized male Sprague-Dawley rats were subjected to testicular torsion-induced ischaemia, followed by reperfusion (TI/R). Immediately after detorsion, randomized animals, including SHAM, received intraperitoneal injections of: (i) vehicle (1 mL/kg 0.9% NaCl solution); (ii) PDRN (8 mg/kg); (iii) DMPX (3,7-dimethyl-1-propargilxanthine, 0.1 mg/kg); or (iv) PDRN (8 mg/kg) + DMPX (0.1 mg/kg). Animals were euthanized at 1, 7 and 30 days following reperfusion. Vascular endothelial growth factor (VEGF) expression is normally associated with adenosine A2A receptor stimulation. After treatment, VEGF mRNA/protein expression quantified by qPCR and Western blot, vascular endothelial growth factor receptor-1 (VEGFR1) and endothelial nitric oxide synthase (eNOS) mRNA measured by qPCR, VEGF and VEGFR1 assessed using immunohistochemical methods, histological staining and spermatogenic activity were all analysed. Testis ischaemia-reperfusion (TI/R) injury caused increases in VEGF mRNA and protein, VEGFR1 and eNOS mRNA, histological damage and reduced spermatogenic activity. Immunostaining showed a lower expression of VEGF in germinal epithelial cells and a strong expression of VEGFR1 in Leydig cells after TI/R. PDRN administration increased significantly VEGF message/protein, VEGFR1 and eNOS message, decreased histological damage and ameliorated spermatogenic activity. PDRN might be useful in the management of testicular torsion.

Activation of adenosine A2A receptors by polydeoxyribonucleotide increases vascular endothelial growth factor and protects against testicular damage induced by experimental varicocele in rats

In rat experimental varicocele, polydeoxyribonucleotide (PDRN) induces vascular endothelial growth factor (VEGF) production, thereby enhancing testicular function. This may point to a new therapeutic approach in human varicocele.