Effects of heterologous platelet-rich plasma gel on standardized dermal wound healing in rabbits

Platelet-Rich Plasma Extract Derived from Animals Shows Potential in Promoting Wound Healing and Suppressing Inflammatory Response in Skin Cells

Platelet-rich plasma (PRP) is an extract enriched with growth factors that facilitate skin regeneration and rejuvenation. Here, the functionalities of PRP derived from various animal sources have been investigated and compared, focusing on its potential therapeutic applications in skin regeneration. Total antioxidant capacity, wound closure, and melanin content in cultured keratinocytes were used to evaluate the efficacy of different animal PRP sources. The PRP derived from deer exhibited the highest performance and was selected for subsequent proteomic and metabolomic analyses. Our findings indicate that deer blood is an optimal source of animal-derived PRP, demonstrating significant properties in promoting wound healing, anti-inflammatory responses, and skin regeneration. This identified PRP from deer sources can be developed as a safe and effective product for skin rejuvenation and regeneration.

Comparison of the effects of platelet-rich plasma and platelet-rich fibrin on the healing process of a rat's mucosal wound

Due to the problems associated with the use of PRP, a platelet concentrates without coagulation factors, called platelet-rich fibrin (PRF), has been developed that, in addition to tissue regeneration and wound healing, contains more white blood cells (WBCs), which are important in the wound healing process. In this study, the effect of these two platelet-rich plasmas on the thickness of the epithelium, the number of blood vessels and fibroblasts, and wound area were measured in two groups of PRP and PRF and at different periods. We divided the rats into three groups: the control group, the group receiving PRP, and the group receiving PRF. The results showed a significant difference in the number of fibroblasts, wound area, thickness of epithelium, and number of vessels in all three groups. Based on the results, the use of PRP and PRF in wounds can accelerate the formation of epithelium, create better and more blood vessels, create a platform for the migration and formation of fibroblast cells, and facilitate faster wound closure. Also, comparing PRP and PRF, it can be concluded that, finally, PRF acts better than PRP in epithelialization.

Engineering homologous platelet-rich plasma, platelet-rich plasma-derived exosomes, and mesenchymal stem cell-derived exosomes-based dual-crosslinked hydrogels as bioactive diabetic wound dressings

The management of diabetic wounds remains a critical therapeutic challenge. Platelet-rich plasma (PRP) gel, PRP-derived exosomes (PRP-Exos), and mesenchymal stem cell-derived exosomes (MSC-Exos) have demonstrated therapeutic potential in wound treatment. Unfortunately, their poor mechanical properties, the short half-lives of growth factors (GFs), and the burst release of GFs and exosomes have limited their clinical applications. Furthermore, proteases in diabetic wounds degrade GFs, which hampers wound repair. Silk fibroin is an enzyme-immobilization biomaterial that could protect GFs from proteases. Herein, we developed novel dual-crosslinked hydrogels based on silk protein (SP) (sericin and fibroin), including SP@PRP, SP@MSC-Exos, and SP@PRP-Exos, to promote diabetic wound healing synergistically. SP@PRP was prepared from PRP and SP using calcium gluconate/thrombin as agonist, while SP@PRP-Exos and SP@MSC-Exos were derived from exosomes and SP with genipin as crosslinker. SP provided improved mechanical properties and enabled the sustained release of GFs and exosomes, thereby overcoming the limitations of PRP and exosomes in wound healing. The dual-crosslinked hydrogels displayed shear-induced thinning, self-healing, and eradication of microbial biofilms in a bone-mimicking environment. In vivo, the dual-crosslinked hydrogels contributed to faster diabetic wound healing than PRP and SP by upregulating GFs expression, down-regulating matrix metalloproteinase-9 expression, and by promoting an anti-NETotic effect, angiogenesis, and re-epithelialization. Hence, these dual-crosslinked hydrogels have the potential to be translated into a new generation of diabetic wound dressings.

The usefulness of platelet-rich plasma to manage skin wounds: A meta-analysis

A meta-analysis investigation to measure the usefulness of platelet-rich plasma (PRP) to manage skin wounds (SWs). A comprehensive literature inspection till February 2023 was applied and 1349 interrelated investigations were reviewed. The 22 chosen investigations enclosed animals' SWs were in the chosen investigations' starting point, 3348 of them were treated with PRP, and 2259 were control. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were used to compute the value of the usefulness of PRP to manage SWs by the dichotomous and continuous approaches and a fixed or random model. PRP significantly higher percent of decreases in open wound area (OWA) (MD, 10.07; 95% CI, 6.55-13.59, P < 0.001), and lower healing time (HT) (MD, -6.31; 95% CI, -10.69 to -1.93, P = 0.005) compared to control in animals' SWs. PRP had a significantly higher percent of decreases in OWA and lower HT compared to control in animals' SWs. However, caused of the small sample sizes of several chosen investigations for this meta-analysis, care must be exercised when dealing with its values.

Locally Injected Autologous Platelet-Rich Plasma Improves Cutaneous Wound Healing in Cats

Cutaneous defects in cats are commonly encountered in clinical practice, and healing can be accomplished by first or second intention. Platelet-rich plasma (PRP) is characterized by a plasma concentration containing a large number of platelets in a small volume of plasma. The objective of the present study was to record the efficacy of PRP infiltration in open wounds in laboratory cats. Six wounds were created in the dorsal midline of eight laboratory cats, with the wounds of one side designated as the PRP group and the wounds of the other side as the control group. Wound healing was evaluated by daily clinical examination, planimetry, laser Doppler flowmetry, and histologic examination on days 0, 7, 14, and 25, and by measurement of metalloproteinases (MMPs)-2 and -9 and tissue inhibitor metalloproteinase (TIMP)-1 on days 0, 14, and 25. Based on the results of the present study, the mean time for full coverage with granulation tissue was shorter in the PRP group, the mean contraction and total wound healing percentage were increased compared to the control group, and finally, the perfusion measured with laser Doppler flowmetry was higher in the PRP group during all examination days. In conclusion, this is the first study focusing on the topical application of PRP in the treatment of open wounds in laboratory cats, and our results are encouraging—showing a more rapid healing in the PRP group.

Current applications of platelet gels in wound healing-A review

Human platelets play important roles in several physiologic and pathologic processes. Platelet concentrates are activated with thrombin or calcium, resulting in a viscous coagulum (platelet gel [PG]), composed of 95% platelets at least. PG is increasingly used for the treatment of a variety of soft and hard tissue defects, most notably in the management of chronic non-healing wounds. During wound healing, platelets not only play a critical role in primary hemostasis and thrombosis, but also release growth factors and cytokines to promote tissue regeneration, enhance collagen synthesis, and trigger an immune response. This review addresses a variety of aspects relevant to the functions of well-known platelet growth factors, animal and clinical studies of PG in the last decade, and different sources of platelets for PG. PG is used for non-healing chronic wounds, such as oral ulcerations related to epidermolysis bullosa and chronic graft-versus-host disease, for those, the traditional treatment effect is poor. PG maybe provide a new therapeutic direction for these diseases. Nevertheless, some uncertainty is present, the number of clinical studies is not enough. Hence, randomized controlled trials are still required to study the potential of the use of PG in the near future.

Use of platelet concentrate gel in second-intention wound healing: a case report

Background

Wound healing is a complex and dynamic process. Healing of acute and chronic wounds can be impaired by patient factors (that is, comorbidities) and/or wound factors (that is, infection). Regenerative medicine products, such as autologous/homologous platelet-rich plasma gel, may speed up the healing process. Autologous/homologous platelet-rich plasma is an advanced wound therapy used for hard-to-heal acute and chronic wounds. The cytokines and growth factors contained in platelet-rich plasma play a crucial role in the healing process.

Case presentation

A 61-year-old Caucasian male patient, suffering from mental retardation following meningitis, with a transplanted kidney due to prior renal impairment, and under immunosuppressant therapy, was submitted to aneurysmectomy of his proximal left forearm arteriovenous fistula. A few days later, the patient came to our attention with substantial blood loss from the surgical site. The wound presented no signs of healing, and after fistula reparation and considering persistent infection of the surgical site (by methicillin-resistant Staphylococcus aureus), surgeons decided for second-intention healing. To favor healing, 10 mL homologous platelet concentrate gel was sequentially applied. After each application, wound was covered with nonadherent antiseptic dressing. After only seven applications of homologous platelet concentrate gel, wound completely recovered and no amputation was necessary.

Conclusions

Topical application of homologous platelet-rich plasma gel in healing wound shows beneficial results in wound size reduction and induces granulation tissue formation. Platelet-rich plasma could be a safe and cost-effective treatment for managing the cutaneous wound healing process to shorten the recovery period and thereby improve patient quality of life.

Effects of homologous and heterologous rich platelets plasma, compared to poor platelets plasma, on cutaneous healing of rabbits

Purpose:

To evaluate and compare the effects of homologous and heterologous PRP (Platelet-Rich Plasma) on the quality and speed of skin wound healing, compared to Poor Platelet Plasma (PPP).

Methods:

Twenty-one male adult rabbits were used; two for preparing homologous PRP, with the rest of them separated randomly in three groups, according to the treatment received: PPP - control (n=5), homologous PRP (n=7), heterologous (n=7). Excisional skin wounds were made on the back of the animals, for the application of homologous and heterologous PPP and PRP. At the 14th post-operative day (POD), the animals were subjected to a new wound, and the treatments were inverted. The wounds were evaluated macroscopically and histologically.

Results:

A larger percentage of scar retraction was observed on the group treated with heterologous PRP, compared to homologous PRP, at the third POD, an increase of 25.03% (p=0.01). No other statistically significant differences among treatments were observed. Among every group, skin healing was efficient, without local adverse effects.

Conclusions:

Heterologous PRP contributed with more tissue retraction at the beginning of the wound healing process. After this, there were no differences on the wound healing skin process treated with PRP or PPP. However, our findings suggest the presence of others plasmatic factors, besides platelets, which could also contribute to the wound healing process, and thus, should be further investigated.

Topical application of lidocaine or bupivacaine in the healing of surgical wounds in dogs

Purpose:

To analyze the anesthetic drugs interference with wound healing when used in the surgical bed.

Methods:

Macro and microscopic aspects of healing of surgical wounds were evaluated after instillation of topical anesthetics without vasoconstrictor or saline solution 0.9% as control in the transsurgical period. Thirty dogs, males and females were divided into two experimental groups. In both groups, two circular punch lesions of 6 mm diameter were performed in the abdomen. In group 1, lidocaine was instilled in one of the lesions and saline solution in the contralateral lesion. In group 2 the procedure was repeated with the use of bupivacaine. The macroscopic assessment of the lesions was performed on the first, third and tenth postoperative day. The excisional biopsy was performed on the tenth day and the samples were submitted for histopathological examination.

Results:

The macroscopic analysis had a significant difference between groups. Microscopic analysis was not significant between groups.

Conclusions:

The topical application of lidocaine and bupivacaine in the surgical wound is feasible and it does not influence skin healing. The benefit of such a practice, which has been the subject of other studies, seems to outweigh the risks.

Análise ultraestrutural do colágeno de feridas cutâneas de coelhos tratadas com plasma rico em plaquetas de equino

RESUMO O colágeno é sintetizado e segregado no espaço extracelular e organizados em fibrilas estriadas de acordo com o tipo de tecido. Utilizaram-se 24 coelhos brancos da raça Nova Zelândia, com idade de 12 meses e com 3,0kg de peso corporal, para avaliar a porcentagem de colágeno das feridas cutâneas tratadas com plasma rico em plaquetas de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A. Os animais foram separados em quatro grupos de igual número e submetidos à remoção de pele na região das linhas médias dorsal torácica (feridas tratadas) e lombar (feridas controle). As feridas torácicas foram tratadas com plasma rico em plaqueta de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A, e as do grupo controle somente com a pomada. Dos animais do grupo I, foi coletado tecido cutâneo, para a avaliação histológica e a ultraestrutural, com três dias de pós-operatório; dos animais do grupo II, com sete dias; do grupo III, com 14 dias; e do grupo IV, com 21 dias. Decorrido o período de avaliação de cada grupo, foi coletado fragmento de pele para avaliação da porcentagem de colágeno, bem como do diâmetro e da densidade da fibrila de colágeno por microscopia eletrônica de transmissão. O tratamento com PRP de equino associado à aplicação tópica da pomada mostrou-se eficaz na maturação das fibrilas colágenas e na antecipação do processo cicatricial.

Randomized Controlled Trial on Autologous Platelet-Rich Plasma Versus Saline Dressing in Treatment of Non-healing Diabetic Foot Ulcers

BACKGROUND

This randomized clinical trial was conducted to assess the role of platelet-rich plasma (PRP) gel as a treatment of clean non-healing diabetic foot ulcer (DFU) in comparison with regular dressing with saline as a control.

METHODS

Patients with DFU were randomly assigned to one of two equal groups: group I received dressing with PRP gel and group II received regular saline dressing. The main outcomes of the study were percent reduction in the dimensions of the DFU, healing of DFU, and complications at 20 weeks of follow-up.

RESULTS

Twenty-four patients were included to the study. The mean age of patients was 55.2 ± 6.4 years. Only three (25%) patients in group I achieved complete healing versus none of group II patients. In total, 8.3% of group I and 41.6% of group II patients did not show any response to treatment. The percent of reduction in the longitudinal and horizontal dimensions of the DFU was significantly greater in group I than group II (43.2% vs 4.1%) and (42.3% vs 8.2%), respectively. The time required to maximum healing was significantly shorter in group I than group II (6.3 ± 2.1 vs 10.4 ± 1.7 weeks, P < 0.0001).

CONCLUSION

The use of PRP gel as a dressing for chronic DFU resulted in a more significant reduction in the size of the ulcer when compared to regular saline dressing. Also the time to reach the point of maximal possible healing with the least wound dimensions was significantly shorter when using PRP as a dressing protocol.

Co-treatment of wounds in rabbit skin with equine platelet-rich plasma and a commercial ointment accelerates healing

Abstract Autologous platelet-rich plasma (PRP) is beneficial in the healing process of reconstructive surgeries, contributing to the stimulation of angiogenesis; however, heterologous plasma has been shown to be more effective. The objective of this study was to verify, by macro- and microscopic evaluation, whether PRP accelerates the healing process as compared to a commercial ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A (study ointment). This study used 24 white New Zealand rabbits, aged 12 months, and each weighing approximately 3 kg. The animals were separated into 4 equal groups and underwent wound induction through skin removal in the thoracic (study wound) and lumbar (control wound) dorsal midline. Study wounds were co-treated with equine PRP and the study ointment. Control wounds were treated with only the study ointment. Group I underwent histological evaluation 3 days after the skin removal procedure, group II after 7 days, group III after 14 days, and group IV after 21 days. A skin fragment was collected from each animal for histological evaluation. The co-treatment with heterologous equine PRP and the study ointment accelerated the healing process in the surgically induced skin wounds, confirming the acceleratory effect of PRP on wound healing.

Autologous Platelet-rich Plasma Eye Drops Accelerate Re-epithelialization of Post-keratoplasty Persistent Corneal Epithelial Defects

Purpose:

To investigate whether autologous platelet-rich plasma (PRP) eye drops accelerate re-epithelialization of post-keratoplasty persistent corneal epithelial defects (PEDs).

Methods:

A total of 34 eyes with PEDs after keratoplasty (24 penetrating keratoplasty and 10 deep anterior lamellar keratoplasty) that were refractory to conventional medical treatments were treated with PRP eye drops every 3 hours. PRP eye drops were prepared with a low- and high-speed centrifugation method and final platelet counts were 700,000-800,000 plt/μl. The mean treatment duration for complete re-epithelialization was compared with the mean treatment duration of conventionally treated corneal defects before the PRP treatment by paired t-test. The mean treatment duration was also statistically analyzed between age groups, gender, indications for keratoplasty, and types of keratoplasty using analysis of variance (ANOVA).

Results:

Treatment with autologous PRP eye drops led to rapid re-epithelialization in all eyes. The mean treatment duration for complete re-epithelialization was 2.47 ± 1.21 weeks, which was significantly shorter than the mean treatment duration of conventionally treated corneal defects before PRP treatment (6.82 ± 1.24 weeks) (P = 0.0001). There was no significant correlation between re-epithelialization time and patients' age, sex, indications for keratoplasty, and techniques of corneal transplantation.

Conclusion:

Treatment with autologous PRP eye drops is an effective and reliable approach that accelerates re-epithelialization of post-transplantation PEDs.

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.

Platelet-rich plasma to treat experimentally-induced skin wounds in animals: A systematic review and meta-analysis

The objective of the study was to review current literature to determine whether the topical application of platelet-rich plasma (PRP) promotes healing in experimentally-induced full-thickness skin wounds in animals. The hypothesis was that the adjunct of PRP has a positive effect on wound healing. An electronic search was carried out on the following databases: Web of Science, Cochrane Library, PubMed, Research Gate, Cochrane Wounds Group, Veterinary Information Network. No publication date nor language restrictions were applied. Randomised and not randomised controlled clinical trials comparing PRP with placebo or with other treatments were included. The reduction of open wound area in PRP-treated (test) wounds compared to control wounds was the primary outcome. Secondary outcomes were healing time and number of healed cases in test group compared to control. The following effect sizes were calculated: the Hedges' g for continuous variables; the odds ratio for binary data. Eighteen controlled clinical trials were included in the qualitative and quantitative synthesis, with a total of 661 wounds. All studies were published in the period 2007-2016. Eight studies were carried out on rodent/lagomorph mammals and 10 on non-rodent/lagomorph mammals. In all included studies, control wounds underwent placebo or were left untreated. The PRP group showed a better healing performance than the control group in each outcome. The effect size was statistically significant considering the primary outcome and the overall aggregation of the three outcomes. The effect size, although in favour of the treatment with PRP, was not significant considering the healing time and the number of healings. The overall heterogeneity was mild or moderate. Five studies reported a high risk of selection bias. The publication bias was always mild or absent. The results support the hypothesis of the positive effects of the PRP when compared to control groups in the treatment of experimentally-induced full-thickness skin wounds in animals. PRP can therefore be considered an effective adjunctive therapy in stimulating second intention healing of acute wounds in healthy animals.

Hydrogel and Platelet-Rich Plasma Combined Treatment to Accelerate Wound Healing in a Nude Mouse Model

Background

Platelet-rich plasma (PRP) contains high concentrations of growth factors involved in wound healing. Hydrogel is a 3-dimensional, hydrophilic, high-molecular, reticular substance generally used as a dressing formulation to accelerate wound healing, and also used as a bio-applicable scaffold or vehicle. This study aimed to investigate the effects of PRP and hydrogel on wound healing, in combination and separately, in an animal wound model.

Methods

A total of 64 wounds, with 2 wounds on the back of each nude mouse, were classified into 4 groups: a control group, a hydrogel-only group, a PRP-only group, and a combined-treatment group. All mice were assessed for changes in wound size and photographed on scheduled dates. The number of blood vessels was measured in all specimens. Immunohistochemical staining was used for the analysis of vascular endothelial growth factor (VEGF) expression.

Results

Differences in the decrease and change in wound size in the combined-treatment group were more significant than those in the single-treatment groups on days 3, 5, 7, and 10. Analysis of the number of blood vessels through histological examination showed a pattern of increase over time that occurred in all groups, but the combined-treatment group exhibited the greatest increase on days 7 and 14. Immunohistochemical staining showed that VEGF expression in the combined-treatment group exhibited its highest value on day 7.

Conclusions

This experiment demonstrated improved wound healing using a PRP–hydrogel combined treatment compared to either treatment individually, resulting in a decrease in wound size and a shortening of the healing period.