A new aspect of in vitro antimicrobial leukocyte- and platelet-rich plasma activity based on flow cytometry assessment.

The current literature suggests that the antibacterial effect of leukocyte- and platelet-rich plasma (L-PRP) is directly related to platelet and leukocyte concentrations. The aim of this study was twofold: first, to evaluate the antimicrobial effect of L-PRP against selected bacterial strains in vitro, and second, to correlate this effect with leukocyte and platelet content in the final concentration. Blood was collected from 20 healthy males, and L-PRP, acellular plasma (AP), and autologous thrombin were consecutively prepared. Flow cytometry analysis of the blood, L-PRP, and AP was performed. The L-PRP gel, liquid L-PRP, and thrombin samples were tested in vitro for their antibacterial properties against seven selected bacterial strains using the Kirby-Bauer disk-diffusion method. There was notable antimicrobial activity against selected bacterial strains. No statistically significant correlations between antimicrobial activities and the platelet concentration in L-PRP were observed. Statistically significant positive correlations between selected leukocyte subtypes and antimicrobial activity were noted. A negative correlation was found between elevated monocyte count and antimicrobial activity of L-PRP against one bacterial strain studied. L-PRP possesses antimicrobial activity and can be potentially useful in the fight against certain postoperative infections. The bactericidal effect of L-PRP is caused by leukocytes, and there exists a relationship among selected leukocyte subtypes and L-PRP antimicrobial activity.

Antibacterial Activity of Leukocyte- and Platelet-Rich Plasma: An In Vitro Study.

The aim of the study was to investigate the leukocyte- and platelet-rich plasma (L-PRP) antimicrobial activity. The studied sample comprised 20 healthy males. The L-PRP gel, liquid L-PRP, and thrombin samples were tested in vitro for their antibacterial properties against selected bacterial strains using the Kirby-Bauer disc diffusion method. Two types of thrombin were used (autologous and bovine). Zones of inhibition produced by L-PRP ranged between 6 and 18 mm in diameter. L-PRP inhibited the growth of Staphylococcus aureus (MRSA and MSSA strains) and was also active against Enterococcus faecalis and Pseudomonas aeruginosa. There was no activity against Escherichia coli and Klebsiella pneumoniae. The statistically significant increase of L-PRP antimicrobial effect was noted with the use of major volume of thrombin as an activator. Additionally, in groups where a bovine thrombin mixture was added to L-PRP the zones of inhibition concerning MRSA, Enterococcus faecalis, and Pseudomonas aeruginosa were larger than in the groups with autologous thrombin. Based on the conducted studies, it can be determined that L-PRP can evoke in vitro antimicrobial effects and might be used to treat selected infections in the clinical field. The major volume of thrombin as an activator increases the strength of the L-PRP antimicrobial effect.

Effect of L-PRP treatment on wound healing after surgical skin incision in an experimental animal model.

AIM OF THE STUDY: The aim of the study was to evaluate the effect of leukocyte- and platelet-rich plasma (L-PRP) treatment on a noncomplicated would healing after surgical skin incision in an experimental animal model. MATERIALS AND METHODS: The blood from 64 male Wistar rats was used to prepare L-PRP before a transverse dorsal incision was made and consecutively closed. At the same time after the surgery was completed, autologous L-PRP in the rats from the L-PRP group (n = 32) and NaCl in the control group (n = 32) were injected subcutaneously into the wound. The examination included clinical observations, laboratory examination, and examination of biopsy specimens taken from sacrificed animals on the second, third, fourth, and sixth days after the surgery (histopathological examination, immunochemistry, molecular examination). RESULTS: In all cases, no healing process complications were noted. The intergroup comparison revealed no statistically significant differences in terms of histopathological, immunohistochemical, and molecular examinations results. In the intragroup analysis, statistically significant differences were observed within each group between periods of observations in terms of immunohistochemical and molecular examinations results. CONCLUSIONS: L-PRP treatment does not significantly accelerate a noncomplicated wound healing after surgical skin incision in an experimental animal model.

The application of L-PRP in AIDS patients with crural chronic ulcers: A pilot study.

PURPOSE: Nonhealing wounds or skin ulcerations are the result of insufficient repair and destruction of a local healing potential. Opportunistic infections which cause a lot of ulcer complications influence the worsening general condition of patients with AIDS, ultimately leading to death. The chronicity of the condition and poor results of conventional therapy have prompted the search for new methods of treatment. MATERIALS AND METHODS: We have examined venous or arteriovenous insufficiency-related extensive crural ulcers in AIDS patients. Crural ulcer healing processes were evaluated with clinical observations and histopathological, immunohistochemical and molecular examinations of tissue samples harvested from the wound edges before and on day 10 after L-PRP cover dressing. RESULTS: Clinical observations showed positive effects of L-PRP in all patients. However, complete wound closure was noted in 60% of cases. Statistical analysis of histological examination showed increased epidermal processes between samples, but the difference was nonsignificant. However, immunohistochemical investigations showed an increased healing process with strong statistical significance. The mean VEGF level before L-PRP usage was 114.3 vessels/mm2 and on day 10 118.9 (p=0.001523). The mean FLK level was 103.2 and 109.9 respectively (p=0.008241). The biggest differences were observed for CD34, with values of 68.2 on day 0 and 100.8 on day 10 (p=0.006982). Molecular analysis generally showed decreased gene expression and confirmed vascular formation and reepithelialization processes. CONCLUSIONS: In our opinion, L-PRP may be used to eradicate microorganisms from wounds, to induce neovascularization, and in unhealed cases prepare the base and edge of the ulcer for skin grafting and tissue expansion procedures.

Benefit of Leukocyte- and Platelet-Rich Plasma in Operative Wound Closure in Oral and Maxillofacial Surgery.

This article reports the influence of an autologous leukocyte- and platelet-rich plasma (L-PRP) injection as a minimally invasive method on supporting wound healing processes after a mandibular odontogenic cystectomy and double mandibular fracture fixation. 113 patients were enrolled into a control group (received no L-PRP injection) and 102 patients were enrolled into an L-PRP group with an oral mucosa incision. 18 patients after a double mandibular fracture were operated on using 2 external submandibular approaches receiving no fluids in the right site (a control group) and an L-PRP injection in the left incision (L-PRP group). Clinical observations showed that the oral mucosa healed faster in patients treated with L-PRP, in comparison to cases where inductive biomaterial was not added. Pain at the L-PRP injection site was relieved within few hours after an operation in patients with double mandibular fractures. However, there were no differences observed in the progression of the healing process. L-PRP possesses inductive properties that could stimulate healing processes and it seems to be one of the most promising methods in the future for the treatment of soft tissue defects.

The "biological chamber" method ­ use of autologous platelet-rich plasma (PRP) in the treatment of poorly healing lower-leg ulcers of venous origin.

UNLABELLED: Wound healing is a complex pathophysiological process, in which platelets play a crucial role. Platelet alpha-granules release growth factors to the wound bed; the factors are necessary in the healing process. In chronic wounds, such as poorly healing lower-leg ulcers of venous origin, there is decreased activity of multiple growth factors, so the concept of exogenous delivery of such factors seems a logical strategy. Platelet-rich plasma therapy in patients with lower-leg ulcers of venous origin combined with conventional treatment methods (previously ineffective in these patients) seems, based on our observation, an important adjunct leading to recovery. The aim of the study was to present an original method of autologous platelet-rich plasma application through the creation of a sort of "biological chamber" containing a concentrate of growth factors. MATERIAL AND METHODS: The described therapy was implemented in 10 patients, who had been ineffectively treated for more than one year in the outpatient setting. Patients with exacerbation of inflammatory process, signs of wound infection and ankle brachial pressure index < 0.8 were excluded from the study. After the application of platelet-rich plasma, further treatment was continued with the use of moist therapy and compression therapy according to a uniform regimen. RESULTS: Complete healing was achieved within 4-10 weeks from the beginning of the product administration in all patients. CONCLUSION: The presented method seems technically simple, effective and relatively inexpensive.

A side-effect induced by the combination of a demineralized freeze-dried bone allograft and leucocyte and platelet-rich plasma during treatment for large bone cysts: a 4-year follow-up clinical study.

During platelet activation over 30 growth factors are released from their alpha granules. By concentrating platelets, higher levels of growth factors are obtained and can be used to stimulate the healing processes. Moreover, during blood centrifugation, huge numbers of leukocytes and thrombocytes can be obtained to form leukocyte and platelet-rich plasma (L-PRP). After platelet degranulation the active gelatinous matrix called leukocyte and platelet-rich gel (L-PRG) is formed. In the present clinical study, we report the influence of PLRG and freeze-dried allografts on healing of large femoral bone cysts. Each of 6 participants was followed on a regular basis with clinical examinations, roentgenograms and dual-energy X-ray absorptiometry (DXA) examinations. Our four-year follow up clinical study using allografts and PLRG in the treatment of large cystic lesions of the proximal femur showed that mixing these substances is not efficient and it might induce unknown local reactions between them causing complete bone graft destruction. Further studies are necessary to fully understand the mechanisms of the local activity of L-PRP gel.

L-PRP/L-PRF in esthetic plastic surgery, regenerative medicine of the skin and chronic wounds.

The use of platelet concentrates for topical use is of particular interest for the promotion of skin wound healing. Fibrin-based surgical adjuvants are indeed widely used in plastic surgery since many years in order to improve scar healing and wound closure. However, the addition of platelets and their associated growth factors opened a new range of possibilities, particularly for the treatment of chronic skin ulcers and other applications of regenerative medicine on the covering tissues. In the 4 families of platelet concentrates available, 2 families were particularly used and tested in this clinical field: L-PRP (Leukocyte- and Platelet-rich Plasma) and L-PRF (Leukocyte- and Platelet-Rich Fibrin). These 2 families have in common the presence of significant concentrations of leukocytes, and these cells are important in the local cleaning and immune regulation of the wound healing process. The main difference between them is the fibrin architecture, and this parameter considerably influences the healing potential and the therapeutical protocol associated to each platelet concentrate technology. In this article, we describe the historical evolutions of these techniques from the fibrin glues to the current L-PRP and L-PRF, and discuss the important functions of the platelet growth factors, the leukocyte content and the fibrin architecture in order to optimize the numerous potential applications of these products in regenerative medicine of the skin. Many outstanding perspectives are appearing in this field and require further research.

Autologous platelets and leukocytes can improve healing of infected high-energy soft tissue injury.

Despite advances in surgical techniques and pharmacology, healing of injury-associated soft tissue defects is frequently complicated by infections, which often requires a secondary intervention. Cytokines are important mediators of healing. Application of autologous platelet-rich plasma enriched in growth factors and antimicrobial proteins, known also as platelet-leukocyte rich plasma (PLRP), represents a novel approach to the treatment of soft tissue and bone healing disturbances. This case is the first report on the application of PLRP in an infected high-energy soft tissue injury and shows that the volume and concentration of platelets and leukocytes is adequate to induce healing processes despite concurrent infection.

Bone graft application from anterior sinus maxillary wall in orbital floor reconstruction.

To analyze the reconstruction of inferior orbital wall with the use of bone graft harvested from anterior maxillary wall. Medical University of Silesia, Chair of Maxillofacial Surgery. Eighteen patients, aged between 16 and 64 years (15 men and 3 women), with posttraumatic orbital floor defects were treated. The technique was applied in 18 patients with defect in orbital inferior wall. In 11 patients, it was "blowout" fracture, and in 7 cases, the orbital wall fracture accompanied the zygomatico-orbital fracture. Bone transplant after fracture revision covered the orbital floor. Primary outcomes were scored during the operation for passive eyeball movement. Secondary outcomes were estimated (i.e., radiograms, healing of the wound, correct sight, and eyeball mobility). In all cases, full improvement was affirmed, and there was no postoperative complication of any type. Our study indicates that the maxillary bone graft technique is a good and simple orbital floor reconstruction method. Shortening of surgery time and limitation of operative procedures are advantages of this method.

Improved treatment of mandibular odontogenic cysts with platelet-rich gel.

BACKGROUND: Platelets play a central role in hemostasis and healing processes. By concentrating platelets, platelet-rich plasma (PRP) with higher levels of growth factors can be obtained, which might stimulate healing processes. After platelet degranulation, massive release of growth factors and active substances occurs and gelatinous matrix-platelet-rich gel (PRG) is formed. OBJECTIVE: In this double-blind study, we report the influence of PRG on healing of mandibular odontogenic cysts. STUDY DESIGN: We examined 23 cases divided into control (no PRG treatment) and experimental (PRG-treated) groups. Each participant was followed on a regular basis with clinical examinations, roentgenograms, and dual-energy x-ray absorptiometry (DEXA) examinations. RESULTS: Clinical observations showed that oral mucosa healed faster in patients treated with PRG compared with cases where gel was not added. Roentgenograms and DEXA examinations showed considerable enhancement of bone regeneration beginning from the 5th week and continuing during subsequent periods after implantation of PRG in the experimental group compared with the control group. CONCLUSIONS: In our opinion, PRG possesses inductive properties that could stimulate the healing processes. The use of autologous growth factors from platelet gel seems to be one of the most promising methods of treatment of bone, cartilage, and soft tissue defects.

The influence of carbon fibres on the resorption time and mechanical properties of the lactide-glycolide co-polymer.

In this study the influence of short carbon fibres (CF) on mechanical properties and degradation time of the lactide-glycolide co-polymer (PGLA) and on the mechanism of bone ingrowth into the implants was determined. Mechanical properties and push-out tests were measured. The pH of solutions and the implants' weights were tested after incubation in Ringer fluid. Analysis was based upon FT-IR and SEM with EDS studies. Pathological examinations were also performed. The in vitro examination revealed that carbon fibres accelerated polymer degradation process and increased the mechanical strength of polymer. In the case of PGLA + CF under in vivo conditions, initially, the superficial polymer degradation with new tissue in-growth was observed. Next, the degradation process included also the inner part of the implant, while the bone began to grow on exposed carbon fibres. In the case of pure PGLA the growth of soft tissue can be observed at the bone-implant interface and in the implant area. Our research indicates that PGLA + CF composite can be used in bone surgery as a short-term multifunctional load-bearing implant, which initially provides a mechanical support. During the time of controlled resorption of PGLA, carbon fibres act as a scaffold for the bone growth.