Locally injected autologous platelet-rich plasma enhanced tissue perfusion and improved survival of long subdermal plexus skin flaps in dogs

Assessment of the quality of the healing process in experimentally induced skin lesions treated with autologous platelet concentrate associated or unassociated with allogeneic mesenchymal stem cells: preliminary results in a large animal model

Regenerative medicine for the treatment of skin lesions is an innovative and rapidly developing field that aims to promote wound healing and restore the skin to its original condition before injury. Over the years, different topical treatments have been evaluated to improve skin wound healing and, among them, mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) have shown promising results for this purpose. This study sought to evaluate the quality of the healing process in experimentally induced full-thickness skin lesions treated with PRP associated or unassociated with MSCs in a sheep second intention wound healing model. After having surgically created full-thickness wounds on the back of three sheep, the wound healing process was assessed by performing clinical evaluations, histopathological examinations, and molecular analysis. Treated wounds showed a reduction of inflammation and contraction along with an increased re-epithelialization rate and better maturation of the granulation tissue compared to untreated lesions. In particular, the combined treatment regulated the expression of collagen types I and III resulting in a proper resolution of the granulation tissue contrary to what was observed in untreated wounds; moreover, it led to a better maturation and organization of skin adnexa and collagen fibers in the repaired skin compared to untreated and PRP-treated wounds. Overall, both treatments improved the wound healing process compared to untreated wounds. Wounds treated with PRP and MSCs showed a healing progression that qualitatively resembles a restitutio ad integrum of the repaired skin, showing features typical of a mature healthy dermis.

Biological prosthesis, platelet enriched plasma and bone marrow stem cells in complicated incisional hernia reconstruction in emergency surgery: a prospective case control study

Numerous innovations have been aided by abdominal wall surgical repair. Abdominal wall surgery was drastically altered by synthetic materials. Tissue engineering was unquestionably first applied to biomaterials. The purpose of the present study is to compare different repeating approaches with rising tissue engineering complexity in repairing complex incisional hernia in emergency setting. Patients with complicated incisional hernia were prospectively included in the study and divided into 4 groups: DR (Direct Repair) group underwent direct reconstruction of the abdominal wall, BR (Biological mesh Repair) group underwent reconstruction of the abdominal wall with biological mesh (retro-muscular), BPR [Biological mesh and Platelet Enriched Plasma (PEP), gel] group underwent reconstruction of the abdominal wall with Biological mesh (retro-muscular) and PEP, BPSR (biological mesh, PEP gel and Bone Marrow Stem Cells) group underwent reconstruction of the abdominal wall with biological mesh (retromuscular), PEP and Bone Marrow Stem cells (BMSc). Forty patients were enrolled. Patients in the DR group experienced a higher rate of severe complication (p<0.05). Recurrence rates were 60% for DR patients, 20% for BM patients and 10% for the BM+PEP group (p<0.05). Median follow-up period was 64.6, 55.7 and 55.8 months (p<0.05). 7- and 30-days abdominal wall thickness is progressively increased by different techniques: BP, BP+PEP and BP+PEP+BMSc (p<0.05). No mortality was registered. Tissue engineering techniques in abdominal wall reconstruction showed promising results. They seem to reduce the recurrence rate without increasing complication one in complicated incisional abdominal wall hernia. Although many aspects are yet to be determined and standardized, it seems extremely important to continue research and experimentation in this field.

Evaluation of Survival of Subdermal Plexus Skin Flaps in 8 Cats After Injection of Platelet Rich Plasma

The aim of the present study was to evaluate the effect of platelet-rich plasma injection on the survival of experimentally developed subdermal plexus skin flaps in cats. Two flaps, 2 cm wide and 6 cm long were created bilaterally in the dorsal midline in 8 cats. Each flap was randomized to 1 of 2 groups: platelet-rich plasma injection and control. After flap development, the flaps were immediately placed back on the recipient bed. Then 1.8 mL of platelet-rich plasma was equally injected into 6 different parts of the treatment flap. All flaps were evaluated macroscopically daily and on days 0, 7, 14, and 25 by planimetry, Laser Doppler flowmetry, and histology. Mean flap survival on day 14 was 80.437 % (±22.745) for the treatment group and 66.516 % (±24,12) for the control group with no statistically significant difference between the 2 groups (P = .158). Histologically, a significant difference was found between the base of the PRP and the control flap in edema score on day 25 (P = .034). In conclusion, there is no evidence to support the use of platelet-rich plasma in subdermal plexus flaps in cats. However, the use of platelet-rich plasma may aid in reducing edema of subdermal plexus flaps.

Platelet-rich plasma: a comparative and economical therapy for wound healing and tissue regeneration

Rise in the incidences of chronic degenerative diseases with aging makes wound care a socio-economic burden and unceasingly necessitates a novel, economical, and efficient wound healing treatment. Platelets have a crucial role in hemostasis and thrombosis by modulating distinct mechanistic phases of wound healing, such as promoting and stabilizing the clot. Platelet-rich plasma (PRP) contains a high concentration of platelets than naïve plasma and has an autologous origin with no immunogenic adverse reactions. As a consequence, PRP has gained significant attention as a therapeutic to augment the healing process. Since the past few decades, a robust volume of research and clinical trials have been performed to exploit extensive role of PRP in wound healing/tissue regeneration. Despite these rigorous studies and their application in diversified medical fields, efficacy of PRP-based therapies is continuously questioned owing to the paucity of large samplesizes, controlled clinical trials, and standard protocols. This review systematically delineates the process of wound healing and involvement of platelets in tissue repair mechanisms. Additionally, emphasis is laid on PRP, its preparation methods, handling, classification,application in wound healing, and PRP as regenerative therapeutics combined with biomaterials and mesenchymal stem cells (MSCs).

Local wound management: A review of modern techniques and products

Management of wounds is a commonly performed and essential aspect of small animal veterinary medicine. Appropriate wound management is a difficult art to master, due to the inherent complexity of the clinical scenario, as well as the ever-evolving nature of the field with the constant addition of new products and techniques. This article reviews key concepts that may help the practitioner better understand the natural process of wound healing, factors that delay healing and strategies to help improve the local wound environment to make it more conducive to healing during open wound management. The concept of wound bed preparation is defined before common local wound management strategies, such as wound lavage and debridement, are discussed in more detail. Key aspects of the management of biofilms and appropriate use of antimicrobial agents are also reviewed. Finally, the concept of moist wound healing and its impact in modern wound management is explained before a broad variety of types of wound dressings are reviewed, with a particular focus on active dressings.

Case Report: Surgical Treatment of Severe Facial Wounds and Proptosis in a Dog Due to a Traffic Accident

Although facial wounds caused by traffic accidents in dogs are common, the surgical management of severe facial injuries involving the soft tissue, bone, dentition, nose and orbit are challenging. A 2 year-old Korean Jindo dog was diagnosed with severe skin defects of the face and proptosis caused by a vehicular accident. Along the left lateral maxilla, severe injury involving the overlying skin and platysma muscle occurred, to the extent that the middle part of the sphincter colli profundus pars intermedia muscle was exposed. Repair surgeries of the skin defects and globe displacement were performed using a local subdermal plexus rotation flap and a partial transposition of the dorsal rectus muscle combined with small intestinal submucosa (SIS) instead of enucleation as the first attempt. SIS was used to sustain the torn medial region. In this case, the surgery resulted in good cosmetic and functional outcome in the dog, despite the atypical complexities upon presentation.

Autologous Platelet-Rich Plasma Enhances the Healing of Large Cutaneous Wounds in Dogs

Platelet-rich plasma (PRP) is known to play a crucial role in skin wound healing, in both Human and Veterinary Medicine. Remarkably, until now, no studies have reported PRP treatment in subacute full-thickness skin wounds of the dog. The aim of this study was to evaluate the effects of two consecutive applications of autologous PRP, with the second application after 15 days, in 6 dogs showing large subacute skin wounds. The percentage of contraction, re-epithelialization and healing in all treated patients indicated that no complications or side effects, associated with consecutive PRP treatments, occurred in any patient and all wounds achieved complete closure and re-epithelialization. Our results suggest a positive effect of repeated autologous topical PRP treatments in large cutaneous subacute wounds of different etiology. Therefore, this PRP treatment could represent a simple, cost-effective, and valid alternative to promote healing processes in subacute large wounds cases in dogs.

Rheological Properties and Growth Factors Content of Platelet-Rich Plasma: Relevance in Veterinary Biomedical Treatments

Platelet-rich plasma (PRP) is a nontransfusional hemocomponent, considered as a powerful concentrate of growth factors (GFs) therapeutically used to stimulate tissue regeneration. The use of autologous PRP, as the patient’s own biological material, for therapeutic purposes represents a safe and effective alternative to conventional treatments in both human and veterinary medicine. The aim of this study was the characterization of canine PRP from rheological and biological points of view. Thus, a characterization of the viscoelastic properties of the PRP systems was performed in order to clarify the influence of different calcium concentrations, in the presence of autologous thrombin-rich solution, on the PRP gels’ mechanical properties, from which the applicability of these systems in biomedical treatments is strongly dependent. Then, an evaluation of the content of GFs in PRP, activated or not with thrombin, and stored at different temperatures (37 °C and −20 °C) was performed over time, outlining, for the first time, the importance of the effect of physiological temperature (37 °C) on the production of GFs. A clinical case study conducted in a dog with a complete rupture of the common calcaneal tendon (Achilles tendon) confirmed the relevance of this hemocomponent in the daily veterinary clinical activity and the potential translational value for human health.

Indications, complications, and outcomes associated with subdermal plexus skin flap procedures in dogs and cats: 92 cases (2000-2017)

OBJECTIVE

To describe indications, complications, and outcomes associated with subdermal plexus skin flap (SPSF) procedures in dogs and cats.

ANIMALS

53 dogs and 20 cats that received SPSFs for reconstruction of skin defects from 2000 to 2017.

PROCEDURES

Medical record data were collected and summarized regarding patient signalment, indication for the SPSF procedure, type and location of SPSF, complications, and outcome.

RESULTS

92 SPSF procedures (64 in dogs and 28 in cats) were included. Indications for the procedures included tumor excision (n = 37 [40%]), acute wound (14 [15%]) or chronic wound (28 [30%]) reconstruction, surgical scar revision (7 [8%]), and other reasons (6 [7%]). Types of SPSFs included advancement (31 [34%]), axillary fold (20 [22%]), inguinal fold (20 [22%]), rotation (16 [17%]), transposition (3 [3%]), and distant direct (2 [2%]). Complications were noted for 47 (51%) procedures at a mean ± SD of 6.9 ± 4.0 days after surgery and were classified as minor (34 [37%]) or major (13 [14%]). Outcome was considered excellent for 44 (48%) procedures, good for 33 (36%), fair for 13 (14%), and poor for 2 (2%).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that approximately half of SPSF procedures in dogs and cats can be expected to be followed by a complication, occurring at a mean of 1 week after surgery, and yet with appropriate management of these complications, a good to excellent outcome was possible. Owners should be counseled about the likely need for additional visits and costs associated with treatment of postoperative complications.

Prospective Evaluation of Feline Sourced Platelet-Rich Plasma Using Centrifuge-Based Systems

Objective: To evaluate the hematologic components of platelet-rich plasma (PRP) generated using feline blood with two commercially available centrifuge-based systems^1,2.

Materials and methods: Twenty healthy adult cats were enrolled in this prospective study from November 2018 to January 2019. Feline blood samples were obtained for analysis of whole blood (WB) cellular components and preparation of PRP product. PRP was prepared using two commercial systems and complete blood count (CBC) testing was performed on both WB and PRP samples. The cellular composition of the PRP product was compared to the WB sample for each patient.

Results: Both systems showed significant decrease of median RBC concentration in PRP products compared to WB samples (P = 0.002 for both systems). System 1 significantly decreased median WBC concentration (P = 0.002). System 2 decreased WBC concentration, though statistical significance was not reached (P = 0.63). Median platelet concentration was decreased by 3% using System 1, and increased by 187% using System 2. Platelet aggregation presented a challenge with 8/20 (40%) of samples demonstrating platelet aggregation.

Clinical relevance: Commercial systems available for generation of PRP may be useful for creating a feline sourced product and in this study showed promise in decreasing RBC and WBC concentration. Neither system tested achieved 2–5 times platelet concentration from baseline. Platelet aggregation presented a significant obstacle to reliable generation of PRP products using feline blood. This treatment modality may be particularly beneficial for feline patients with osteoarthritis and soft tissue injuries, though first characterizing the PRP product made using feline blood is critical to validate its use in further clinical studies.

Antimicrobial action of autologous platelet-rich plasma on MRSA-infected skin wounds in dogs

Effective antimicrobial preparations, other than antibiotics, are important for the treatment of potentially fatal drug-resistant infections. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of hospital-acquired and post- operative infections. Fortunately, the antimicrobial properties of platelet-rich plasma (PRP) against various microorganisms enable its potential use as an alternative to conventional antibiotics. The present work was designed to evaluate the hypothesized antimicrobial activity of PRP against MRSA infected skin wounds. Six adult male dogs were divided equally into control and PRP groups. Unilateral circular full-thickness skin wounds were created then a MRSA suspension was injected locally. Treatment started at 1st week post infection with subcutaneous infiltration of autologous activated PRP every week in the PRP group and with topical application of clindamycin cream twice daily in the control group. PRP decreased wound size and significantly increased wound contractility and re-epithelization, as confirmed by histopathological and immunohistochemical findings. Also PRP treated group showed significant decrease in ROS and redox imbalance with over expression of the TNF-α and VEGFA genes that indicate angiogenesis and maximum antibacterial activity after three weeks. In conclusion, CaCl₂-activated PRP exhibited antimicrobial activity against MRSA infection, which improved the infected wound healing re-epithelization and granulation tissue formation.

Effect of Autologous Platelet-Rich Plasma Gel on Skin Flap Survival

BACKGROUND Skin flap grafting is one of the most common tissue transplantations for wound repair and organ reconstruction. Thus, improving the survival rate of the transplanted skin flap is important. Platelet-rich plasma (PRP) is an autologous platelet concentrate obtained from whole blood. It has been widely used in repairing tissue defects. Considering that the PRP gel has similar biological characteristics, this study used PRP gel for skin flap transplantation. MATERIAL AND METHODS PRP gel from Sprague-Dawley (SD) rats was prepared and the growth factor concentration was determined. A rat skin flap model was established to evaluate the survival rate of skin flap. Morphologic evaluation was also done. RESULTS We found that the PRP gel increased the survival rate of the skin flap. In addition, it reduces the inflammation response in skin flap transplantation and has better effects in terms of generating new soft tissue. CONCLUSIONS The effectiveness PRP gel in skin flap transplantation is satisfactory. The possible mechanisms by which PRP gel promotes the survival of the skin flap includes platelets, growth factors, immune activity factor, and fibrin. PRP could be a new clinical method for promoting skin flap survival.

Combined plasma rich in growth factors and adipose-derived mesenchymal stem cells promotes the cutaneous wound healing in rabbits

BACKGROUND

The use of Plasma Rich in Growth Factors (PRGF) and Adipose Derived Mesenchymal Stem Cells (ASCs) are today extensively studied in the field of regenerative medicine. In recent years, human and veterinary medicine prefer to avoid using traumatic techniques and choose low or non-invasive procedures. The objective of this study was to evaluate the efficacy of PRGF, ASCs and the combination of both in wound healing of full-thickness skin defects in rabbits. With this purpose, a total of 144 rabbits were used for this study. The animals were divided in three study groups of 48 rabbits each depending on the administered treatment: PRGF, ASCs, and PGRF+ASCs. Two wounds of 8 mm of diameter and separated from each other by 20 mm were created on the back of each rabbit: the first was treated with saline solution, and the second with the treatment assigned for each group. Macroscopic and microscopic evolution of wounds was assessed at 1, 2, 3, 5, 7 and 10 days post-surgery. With this aim, 8 animals from each treatment group and at each study time were euthanized to collect wounds for histopathological study.

RESULTS

Wounds treated with PRGF, ASCs and PRGF+ASCs showed significant higher wound healing and epithelialization rates, more natural aesthetic appearance, significant lower inflammatory response, significant higher collagen deposition and angiogenesis compared with control wounds. The combined treatment PRGF+ASCs showed a significant faster cutaneous wound healing process.

CONCLUSIONS

The combined treatment PRGF+ASCs showed the best results, suggesting this is the best choice to enhance wound healing and improve aesthetic results in acute wounds.

Platelet Rich Plasma: New Insights for Cutaneous Wound Healing Management

The overall increase of chronic degenerative diseases associated with ageing makes wound care a tremendous socioeconomic burden. Thus, there is a growing need to develop novel wound healing therapies to improve cutaneous wound healing. The use of regenerative therapies is becoming increasingly popular due to the low-invasive procedures needed to apply them. Platelet-rich plasma (PRP) is gaining interest due to its potential to stimulate and accelerate the wound healing process. The cytokines and growth factors forming PRP play a crucial role in the healing process. This article reviews the emerging field of skin wound regenerative therapies with particular emphasis on PRP and the role of growth factors in the wound healing process.

Wound Closure, Tension-Relieving Techniques, and Local Flaps

Wounds are often addressed by primary or delayed primary closure. Although many skin wounds could go on to heal by second intention, this results in a less cosmetic outcome, takes longer, and in the long run, is often more expensive. As a general rule, the simplest method of wound closure that is likely to succeed should be chosen. If tension is present at the wound edges, wound dehiscence is likely to occur. Using specific techniques to relieve tension on wound edges and recruiting local flaps from neighboring regions are useful ways to achieve wound closure.