The effect of platelet-rich plasma on composite graft survival

Comparison of Two Human Skin Cell Isolation Protocols and Their Influence on Keratinocyte and Fibroblast Culture

For the development of advanced therapies, the use of primary cells instead of cell lines is preferred. The manufacture of human tissue-engineered skin substitutes requires efficient isolation and culture protocols allowing a massive expansion of the cells in culture from an initial specimen of a minimal size. This study compared two skin cell isolation protocols, routinely applied in two clinical laboratories. Epithelial (keratinocytes) and dermal (fibroblasts) cells were isolated and cultured from three human skin biopsies (N = 3). The two-step digestion protocol (LOEX-Protocol) firstly used thermolysin to enzymatically disrupt the dermal-epidermal junction while, for the one-step digestion protocol (UPCIT-Protocol), mechanical detachment with scissors was applied. Then, the epidermal and dermal layers were digested, respectively, to achieve cell isolation. The cell size, viability, yield and growth were analyzed over five passages (P). The colony-forming efficiency (CFE) and Keratin 19 (K19) expression of epithelial cells were also assessed after P0 and P1. Regarding the dermal cells, no significant differences were observed in the tested parameters of isolation and culture. However, for the epithelial cells, viability was higher (93% vs. 85%) and the number of cells extracted per cm2 of skin was 3.4 times higher using the LOEX-Protocol compared to the UPCIT-Protocol. No significant difference was observed for any parameter once the keratinocytes were cultured from P1 to P4. The CFE and K19 expression decreased from P0 to P1 in both protocols, probably due to the culture process. This study shows that both protocols enable the efficient isolation of skin dermal and epithelial cells and subsequent culture to produce grafts destined for the treatment of patients.

Comparıson of the effect of the autogenıc and xenogenıc use of platelet-rıch plasma on rabbıt chondrocutaneous composıte graft survıval

The platelet-rich plasma (PRP) has become popular in the medical world due to its content of growth factors and numerous studies are experimental. In experimental studies, the preparation and application of PRP are problematic and allogenic PRP transfers have been preffered, because of the difficulties in preparation of autogenic PRP in animal experiments. Xenogenic transfers and their effects have not been studied in this topic. This study aimed to investigate the effect of autogenic and xenogenic use of PRP on composite graft viability.Methods: Two composite grafts are prepared for each ear of nine rabbits. Each ear was randomly divided into three groups. After the procedure, the wound edges and base were injected with 1 cc serum physiologic, autogenic PRP or 1 cc human-derived xenogenic PRP. At 3 weeks, samples were taken, photographic and histopathological evaluations were made.Results: The graft viability was better in autogenic and xenogenic group compared to the control group. In comprasion of autogenic and xenogenic groups, although the macroscopic evaluation revealed better graft viability and less necrosis in the group which had been treated with autogenic PRP, the difference was not statistically significant. The three groups did not significantly differ in terms of inflammation. Vascularization examined histopathologically. CD31 staining, which was used to evaluate angiogenesis, was significantly higher in the autogenic PRP group than the remaining two groups.Conclusion: Although autogenic PRP has better results histopathologically, the xenogenic use of PRP may be an alternative for studies, when macroscopic evaluation is necessary.

Reducing Risks of Graft Failure for Composite Skin–Cartilage Grafts

Facial skin defects pose unique challenges for the reconstructive surgeon. Aesthetically complex areas involving a free margin-such as the ear, eyelid, columella, columella-lobule interface, soft tissue triangle, alar rim, and internal nasal lining-are particularly demanding, as secondary soft tissue contracture in these locations can lead to a very poor cosmetic outcome. In these cases, composite grafts offer an ideal combination of soft tissue coverage and structural rigidity, all accomplished in a single-stage surgery. Composite grafts are often underused in facial reconstructive surgery due to the tenuous blood supply and high reported rates of graft failure.

Effect of leukocyte-platelet fibrin-rich wound reconstruction followed by full-thickness skin grafting in the treatment of diabetic foot Wagner grade 4 ulcer gangrene (toe area)

This study investigated the effect of L-PRF on promoting full-thickness skin grafting for the treatment of diabetic foot ulcer wounds and attempted to characterize the mechanism. In a retrospective study, we centrifugated 10-20 ml of venous blood at 1006.2 g for 20 min. The fibrin clot between the top oligocellular plasma layer and the bottom erythrocyte layer was extracted and directly used, without compression, to cover the wound after debridement. Patients who received L-PRF before skin grafting underwent surgery earlier than patients in the control group. Skin necrosis occurred in 7 patients (28%) in the L-PRF group and 16 (64%) in the control group. The difference was statistically significant, P < .05. The postoperative infection rate in the control group (56%) was significantly higher than that in the L-PRF group (24%), P < .05. During a mean follow-up of 1 year, ulcer recurrence occurred in 9 patients (36%) in the control group compared with 4 patients (16%) in the L-PRF group, P < .05. The final amputation rate was also higher in the control group (48%) than in the L-PRF group (20%). The difference is statistically significant, P < .05. The Maryland scale score and SF-36 score of the two groups of patients after treatment were significantly better than those before treatment, and the difference was statistically significant (P < .05). The L-PRF group (94.80 ± 4.14) had better foot scores at the last follow-up after treatment than the control group (88.84 ± 5.22) (P < .05). The results showed that L-PRF played a positive role in the treatment of Wagner grade 4 ulcer gangrene with free full-thickness skin grafts.

Anti-inflammation biomaterial platforms for chronic wound healing

Nowadays, there has been an increase in the number of people with chronic wounds, which has resulted in serious health problems worldwide. The rate-limiting stage of chronic wound healing has been found to be the inflammation stage, and strategies for shortening the prolonged inflammatory response have proven to be effective for increasing the healing rate. Recently, various anti-inflammatory strategies (such as anti-inflammatory drugs, antioxidant, NO regulation, antibacterial, immune regulation and angiogenesis) have attracted attention as potential therapeutic pathways. Moreover, various biomaterial platforms based on anti-inflammation therapy strategies have also emerged in the spotlight as potential therapies to accelerate the repair of chronic wounds. In this review, we systematically investigated the advances of various biomaterial platforms based on anti-inflammation strategies for chronic wound healing, to provide valuable guidance for future breakthroughs in chronic wound treatment.

Does the use of Dermojet affect the concentration of platelet-rich plasma? An in vitro experimental investigation

Needle-free injection systems with high jet pressure have been used for seven decades for drug or vaccine administration via intradermal, subcutaneous, and intramuscular routes. These systems are used for the application of mesotherapy drugs in plastic surgery and dermatology. Platelet-rich plasma (PRP) tissue regeneration is applied intradermally by a needle for different indications, such as wound healing and scar revision. To prevent complaints such as pain, erythema, and ecchymosis by patients during this application, PRP was applied using Dermojet, a jet injector system with a spring-loaded system. In this study, after measuring the average platelet count in PRP preparations obtained from 18 volunteers, a 2.5 cc PRP shot into an empty tube was performed with Dermojet. The mean platelet count was measured in a homogenized tube. The same procedures were performed for platelet-poor plasma (PPP). The platelet loss rates for PRP and PPP were compared. In addition, the amount of PRP in each shot of the Dermojet was calculated. When PRP and PPP were applied using the Dermojet, platelet loss was 8.41% and 8.33%, respectively. The difference in the number of platelets formed in PRP and PPP when applied with Dermojet was not statistically significant. PRP application with needle-free injection systems, such as Dermojet, may be an alternative because of patient comfort and the negligible platelet loss compared with the PRP application with the standard needle injection.

Effects of Saccharides from Arctium lappa L. Root on FeCl3-Induced Arterial Thrombosis via the ERK/NF-κB Signaling Pathway

Saccharides from Arctium lappa. L. root (ALR-S) is a high-purity fructosaccharide separated from the medicinal plant Arctium lappa. L. root. These compounds showed many pharmacological effects in previous studies. In the present study, the antithrombotic effects of ALR-S in arterial thrombosis via inhibiting platelet adhesion and rebalancing thrombotic and antithrombotic factor expression and secretion were found in rats and human aortic endothelial cells (HAECs). This study also showed that inhibition of oxidative stress (OS), which is closely involved in the expression of coagulation- and thrombosis-related proteins, was involved in the antithrombotic effects of ALR-S. Furthermore, studies using FeCl₃-treated HAECs showed that ALR-S induced the abovementioned effects at least partly by blocking the ERK/NF-κB pathway. Moreover, U0126, a specific inhibitor of ERK, exhibited the same effects with ALR-S on a thrombotic process in FeCl₃-injured HAECs, suggesting the thrombotic role of the ERK/NF-κB pathway and the antithrombotic role of blocking the ERK/NF-κB pathway by ALR-S. In conclusion, our study revealed that the ERK/NF-κB pathway is a potential therapeutic target in arterial thrombosis and that ALR-S has good characteristics for the cure of arterial thrombosis via regulating the ERK/NF-κB signaling pathway.

Promising impact of platelet rich plasma and carbon dioxide laser for stress urinary incontinence

Objectives

To evaluate the safety, feasibility and efficacy of trans-vaginal fractional micro-ablative CO₂ laser therapy in combination with platelet rich plasma (PRP) for the treatment of stress urinary incontinence (SUI) in women.

Study design

Participants with SUI underwent three sessions of transvaginal CO₂ laser and PRP treatment, administered at 4-6-week intervals. Outcomes were assessed using the bladder function section of the Australian Pelvic Floor Questionnaire (APFQ). The primary outcome was changes in the participants’ symptoms of SUI. Secondary outcomes were related to general bladder function. Outcome differences from baseline (T1) to 3 months (T2) and 12 months (T3) were analysed using Wilcoxon signed-rank tests. Subjective verbal scales were used to assess the degree of pain associated with PRP injections and laser treatment.

Results

Sixty-two women with SUI were enrolled into this study. There were 66% (41/62) of participants who reported improved SUI symptoms from T1 to T2 (p < 0.001) and at T3, 62% (23/37) of patients reported improved SUI symptoms (p < 0.001). From T1 to T2, all bladder function variables were improved significantly (p < 0.002). At T3, significant improvements (p < 0.03) were maintained for all bladder function variables, except pad usage (p = 0.073).

Conclusions

Combining transvaginal fractional CO₂ laser with PRP might be a beneficial treatment for SUI. It may have the potential to be a minimally-invasive and low-risk alternative to surgery, with reduced recovery time.

Skin graft storage in platelet rich plasma (PRP)

Storage of skin grafts for later use is one of the standard applications in surgery. It is the most preferred method to maintain at +4°C in refrigeration after wrapping the surplus grafts into sterile gauze pad moistened with saline. Although there are many studies on the storage of skin grafts, less is known about storing skin grafts with PRP. Twenty-five pieces of 1 × 1 cm² partial thickness skin graft were harvested from 12 patients during the reduction mammoplasty operation. Twenty-four grafts were divided into 4 groups, and each group consisted of 6 grafts, 1 graft was analyzed as Day 0. Grafts in Group 1, 2, and 3 were wrapped by sterile gauze pad moistened by either saline (Group 1) or Hartman (Group 2) or PRP (Group 3). Grafts were analyzed macroscopically and microscopically. There were no significant differences between media for the first 10 days. Decrease in viability was less in saline and PRP wrapped grafts at 20 day, viability decreased significantly in all environments after 20 days. Although there was no significant difference in saline or PRP storage, it was observed macroscopically that the grafts stored in the PRP appeared better.

The Role of Platelet Concentrates in Facial Fat Grafting

Autologous fat grafting is increasingly being used as a method for the repair of facial soft tissue defects and facial rejuvenation, given its low risk of adverse effects and high efficacy. However, the unpredictability of graft retention is a limitation of this procedure. In addition, there is no standard procedure to date for autologous fat grafting. Different methods have been developed to increase the retention of grafted fat. For instance, platelet concentrates have been used to directly deliver bioactive factors to grafted fat. Platelet concentrates also provide incidental therapeutic benefits by enhancing the persistence of fat grafted in the face via the release of growth factors and cytokines. In this review, we describe current strategies for improving the survival of facial fat grafts, mainly focusing on the application of growth factors/cytokines and platelet concentrates to fat grafting.

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

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Therapeutic strategies for enhancing angiogenesis in wound healing

The enhancement of wound healing has been a goal of medical practitioners for thousands of years. The development of chronic, non-healing wounds is a persistent medical problem that drives patient morbidity and increases healthcare costs. A key aspect of many non-healing wounds is the reduced presence of vessel growth through the process of angiogenesis. This review surveys the creation of new treatments for healing cutaneous wounds through therapeutic angiogenesis. In particular, we discuss the challenges and advancement that have been made in delivering biologic, pharmaceutical and cell-based therapies as enhancers of wound vascularity and healing.

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.

Biological Therapies in Regenerative Sports Medicine

Regenerative medicine seeks to harness the potential of cell biology for tissue replacement therapies, which will restore lost tissue functionality. Controlling and enhancing tissue healing is not just a matter of cells, but also of molecules and mechanical forces. We first describe the main biological technologies to boost musculoskeletal healing, including bone marrow and subcutaneous fat-derived regenerative products, as well as platelet-rich plasma and conditioned media. We provide some information describing possible mechanisms of action. We performed a literature search up to January 2016 searching for clinical outcomes following the use of cell therapies for sports conditions, tendons, and joints. The safety and efficacy of cell therapies for tendon conditions was examined in nine studies involving undifferentiated and differentiated (skin fibroblasts, tenocytes) cells. A total of 54 studies investigated the effects of mesenchymal stem-cell (MSC) products for joint conditions including anterior cruciate ligament, meniscus, and chondral lesions as well as osteoarthritis. In 22 studies, cellular products were injected intra-articularly, whereas in 32 studies MSC products were implanted during surgical/arthroscopic procedures. The heterogeneity of clinical conditions, cellular products, and approaches for delivery/implantation make comparability difficult. MSC products appear safe in the short- and mid-term, but studies with a long follow-up are scarce. Although the current number of randomized clinical studies is low, stem-cell products may have therapeutic potential. However, these regenerative technologies still need to be optimized.

Implications of anticoagulants and gender on cell counts and growth factor concentration in platelet-rich plasma and platelet-rich gel supernatants from rabbits

Objectives: Our objectives were as follows: 1) to validate a protocol for producing rabbit platelet-rich plasma (PRP); 2) to determine the influence of two anticoagulants, sodium citrate and acid-citrate-dextrose solution A, and gender on cell count in PRP and growth factor concentration in pure platelet-rich gel supernatants; 3) to correlate the variables evaluated.

Methods: Whole blood from 18 New Zealand rabbits (9 males and 9 females) was obtained with sodium citrate and acid- citrate-dextrose solution A for processing PRP fractions (A and B), which were evaluated for haematology. The PRP fractions were either activated with calcium gluconate or lysated with a detergent. The concentrations of transforming growth factor beta 1 and platelet-derived growth factor BB were assayed by ELISA.

Results: The sodium citrate PRP-B had significantly higher counts of platelets in comparison to PRP-A and whole blood obtained with the same anticoagulant and the homologous acid-citrate-dextrose solution A PRP fraction. The sodium citrate PRP-A had a significantly higher count of leukocytes compared to the homologous acid-citrate-dextrose solution A fraction. All the PRP fractions had a significant leuko-reduction when compared to whole blood. The sodium citrate PRP-A fraction from female rabbits had significantly lower platelet counts and significantly higher leukocyte counts than the same acid-citrate-dextrose solution A fraction. Growth factor concentration was not affected by the type of anticoagulant or gender.

Clinical significance: The type of anticoagulant and gender affected the cell counts in PRP, but they did not influence the growth factor concentration. More complete rabbit PRP studies should be performed before evaluating this type of substance in models of disease.

Salvage of Unilateral Complete Ear Amputation with Continuous Local Hyperbaric Oxygen, Platelet-Rich Plasma and Polydeoxyribonucleotide without Micro-Revascularization

In many cases of complete ear amputation, microvascular surgery is required for tissue perfusion and organ survival. However, microvascular reconstruction is not always feasible in the absence of suitable vessels. Here, we present the case of a 76-year-old man who underwent complete amputation of the left ear after a collapse at home because of cardiogenic syncope. He was treated with primary replantation and underwent a postoperative salvage course including continuous local hyperbaric oxygen therapy (HBOT), platelet-rich plasma (PRP) injections, and polydeoxyribonucleotide (PDRN) injections. The ear was almost completely salvaged, with a tiny eschar at the mid-scapha on both the anterior and posterior aspects. This case demonstrates the efficacy of local HBOT with PRP and PDRN injections.

Effects of Human Adipose-Derived Stem Cells on the Survival of Rabbit Ear Composite Grafts

Background

Composite grafts are frequently used for facial reconstruction. However, the unpredictability of the results and difficulties with large defects are disadvantages. Adipose-derived stem cells (ADSCs) express several cytokines, and increase the survival of random flaps and fat grafts owing to their angiogenic potential.

Methods

This study investigated composite graft survival after ADSC injection. Circular chondrocutaneous composite tissues, 2 cm in diameter, from 15 New Zealand white rabbits were used. Thirty ears were randomly divided into 3 groups. In the experimental groups (1 and 2), ADSCs were subcutaneously injected 7 days and immediately before the operation, respectively. Similarly, phosphate-buffered saline was injected in the control group just before surgery in the same manner as in group 2. In all groups, chondrocutaneous composite tissue was elevated, rotated 90 degrees, and repaired in its original position. Skin flow was assessed using laser Doppler 1, 3, 6, 9, and 12 days after surgery. At 1 and 12 days after surgery, the viable area was assessed using digital photography; the rabbits were euthanized, and immunohistochemical staining for CD31 was performed to assess neovascularization.

Results

The survival of composite grafts increased significantly with the injection of ADSCs (P<0.05). ADSC injection significantly improved neovascularization based on anti-CD31 immunohistochemical analysis and vascular endothelial growth factor expression (P<0.05) in both group 1 and group 2 compared to the control group. No statistically significant differences in graft survival, anti-CD31 neovascularization, or microcirculation were found between groups 1 and 2.

Conclusions

Treatment with ADSCs improved the composite graft survival, as confirmed by the survival area and histological evaluation. The differences according to the injection timing were not significant.

Use of Platelet-rich Plasma for Vulvovaginal Autoimmune Conditions Like Lichen Sclerosus

Background:

Lichen sclerosus (LS) is an inflammatory dermatosis with autoimmune pathogenesis. Although relatively common, its true incidence is unknown and likely underestimated. LS is usually anogenital, but in around 10% of patients, it can present as extragenital lesions. Continuous administration of topical corticosteroids is the mainstay of medical treatment. Other treatments are available but are only occasionally prescribed along with or instead of topical steroids. Injection of platelet-rich plasma (PRP) into affected areas has been reported to result in the regeneration of normal skin. In this study, we aimed to evaluate the safety, symptom resolution, and objective improvement in patients with autoimmune condition like genital LS after treatment with PRP.

Methods:

Over a 2-year period at FBW Gynaecology Plus, we had a total of 28 patients with confirmed LS on biopsy, unresponsive to topical steroid treatment. After acquiring informed consent, patients’ own blood was centrifuged on site and injected under local anesthesia to the external genitalia.

Results:

Almost all of our patients showed clinical improvement in the size of their lesions, and in 8 cases, lesions totally disappeared after treatment with PRP. Symptoms disappeared in 15 of the 28 patients after treatment, with no need for further steroid therapy in 23 patients. Thirteen women experienced partial symptom relief.

Conclusions:

Based on our limited findings, we hypothesize that PRP presents a potential alternative to topical steroids for treatment of vulvovaginal autoimmune conditions such as LS. A larger pilot and/or randomized controlled trial study is required to evaluate this finding further.

The Clinical Efficacy of Autologous Platelet-Rich Plasma Combined with Ultra-Pulsed Fractional CO2 Laser Therapy for Facial Rejuvenation

Ultra-pulsed fractional CO₂ laser is an efficient, precise, and safe therapeutic intervention for skin refreshing, although accompanied with prolonged edema and erythema. In recent years, autologous platelet-rich plasma (PRP) has been proven to promote wound and soft tissue healing and collagen regeneration. To investigate whether the combination of PRP and ultra-pulsed fractional CO₂ laser had a synergistic effect on therapy for facial rejuvenation. Totally, 13 facial aging females were treated with ultra-pulsed fractional CO₂ laser. One side of the face was randomly selected as experimental group and injected with PRP, the other side acted as the control group and was injected with physiological saline at the same dose. Comprehensive assessment of clinical efficacy was performed by satisfaction scores, dermatologists' double-blind evaluation and the VISIA skin analysis system. After treatment for 3 months, subjective scores of facial wrinkles, skin texture, and skin elasticity were higher than that in the control group. Similarly, improvement of skin wrinkles, texture, and tightness in the experimental group was better compared with the control group. Additionally, the total duration of erythema, edema, and crusting was decreased, in the experimental group compared with the control group. PRP combined with ultra-pulsed fractional CO₂ laser had a synergistic effect on facial rejuvenation, shortening duration of side effects, and promoting better therapeutic effect.

Platelet Preparations for Use in Facial Rejuvenation and Wound Healing: A Critical Review of Current Literature

In facial plastic surgery, the potential for direct delivery of growth factors from platelet preparations has been of particular interest for use in facial rejuvenation, recovery after facial surgery, and wound healing. A literature search was conducted through PubMed for the terms PRP, PRFM, platelet-rich plasma, platelet-rich fibrin matrix, platelet preparations, platelet therapy, growth factors, platelet facial, platelet facial rejuvenation, platelet wound healing, platelet plastic surgery. Articles pertaining to the use of platelet preparations in facial surgery and wound healing in plastic surgery after 2001 were included. Thirteen in vitro studies showed use of platelet-rich plasma (PRP) and platelet-rich fibrin matrix (PRFM) had a significant effect on cellular activity. Twenty-four out of 28 animal studies exhibited favorable results with use of a platelet preparation, including five of six studies that showed enhanced fat graft survival with addition of a platelet preparation. Twenty-three case series and clinical trials were identified, only two of which showed no differences. Twenty-one reported favorable results with use of various platelet preparations. A total of 47 studies used PRP, four studies evaluated Leukocyte-rich PRP, and fourteen studies used PRFM. The vast majority of studies examined show a significant and measurable effect on cellular changes, wound healing, and facial esthetic outcomes with use of platelet preparations, both topical and injectable. One must also consider possible publication bias against null results that may have had an influence on the data that were available for review. However, the preponderance of studies suggests that platelet preparations might represent an as-of-yet untapped adjunct in facial plastic surgery.

20-Hydroxyeicosatetraenoic acid involved in endothelial activation and thrombosis

Endothelial cells play an important role in the process of coagulation and the function of platelets. We have previously reported that 20-hydroxyeicosatetraenoic acid (20-HETE), a metabolite of arachidonic acid, increased platelet aggregation and induced hemostasis. The purpose of the present study is to investigate whether 20-HETE-mediated endothelial activation has effect on the coagulation and platelet aggregation. C57Bl/6 mice were treated with PBS or 20-HETE (20 μg/kg) for 2 h, and then we performed a carotid artery or femoral artery thrombosis model by FeCl3. Detection of blood flow indicated that 20-HETE pretreatment accelerated formation of thrombus in both common carotid artery and femoral artery. In vitro, the secretion and expression of von Willebrand factor (vWF) in cultured human umbilical vein endothelial cells (HUVECs) with 20-HETE stimulation were increased, subsequently. The protein level of vWF in HUVECs was decreased at 1 h but increased with prolonged treatment with 20-HETE (>4 h). In contrast, vWF in the culture medium was increased under administration of 20-HETE at 1 h. As a result, adhesion of platelets on HUVECs was significantly increased by 20-HETE. In HUVECs, the extracellular signal-regulated kinase (ERK) pathway was activated by 20-HETE in a dose-dependent manner, and the inhibitors of ERK and L-type Ca2+channel blocked the release of vWF mediated by 20-HETE. In conclusion, 20-HETE instigates endothelial activation and induces the expression and secretion of vWF via the activation of ERK and calcium channel and therefore triggers thrombosis.