Production of VEGF and b-FGF in drainage fluid from patients undergoing incisional hernia repair

Wound healing is a complex process involving interaction between different cell types, such as growth factors. Among these, vascular endothelial growth factors (VEGF) and basic fibroblast growth factors (b-FGF) are the most important. The aim of this study was to assess the production of VEGF and b-FGF in wound drainage fluid from patients undergoing incisional abdominal hernia repair. Ten female patients with abdominal midline incisional hernia undergoing surgical repair were included in this study. In all cases a closed suction drain was placed in the wound below the fascia and removed on postoperative day 4. Wound fluid was collected on the I, II, III and IV day and its amount at each time was recorded. VEGF and b-FGF production were evaluated as the quantity produced in 24 hours. In all patients the amount of drainage fluid from the surgical wound was highest on the I day after surgery, after which there was a significant reduction. VEGF production increased progressively after the operation proving significantly higher only on the IV day. The amount of b-FGF, in contrast, was higher on the I day, decreasing thereafter on the following postoperative days. Analysis of the production of growth factors in the drainage fluid has enabled us to better assess the events that occur following surgical wounds and has confirmed the physiology of the healing process and the possible use of these factors in modulating positive healing.     

Differential angiogenic and proliferative activity of surgical and burn wound fluids

BACKGROUND: Invasive surgical wounds exhibit the rapid production of a robustly proangiogenic environment. To compare the immediate angiogenic environment of wounds of different types, the angiogenic activity of fluid derived from burn injuries and wounds confined to the dermis was examined and compared with that of deeper surgical wounds. METHODS: The angiogenic activity of surgical wound fluid (SWF) (n = 7), skin graft wound fluid (SGF) (n = 3), and burn wound fluid (BWF) (n = 4) was assessed by measuring endothelial cell (EC) proliferative activity, EC chemotactic activity, and angiogenic activity in the rat corneal assay. The fibroblast growth factor-2 (FGF-2) level of each wound fluid was determined by enzyme-linked immunosorbent assay. RESULTS: SWF exhibited significant EC proliferative activity, SGF exhibited intermediate activity, and BWF displayed no EC proliferative activity. Seventy-one percent of SWF samples, 33% of SGF, and 0% of BWF contained significant EC chemotactic activity. Each wound fluid sample that demonstrated significant chemotactic activity also evoked a positive corneal angiogenic response. SWF contained 914 +/- 170 pg/mL of FGF-2, whereas SGF and BWF contained just 164 +/- 54 pg/mL and 37 +/- 7 pg/mL of FGF-2, respectively. CONCLUSION: The results suggest that injuries confined to the dermis, whether thermal or excisional, elicit a less robust initial angiogenic stimulus than deep surgical wounds.     

Activation of PLC and PI 3 kinase by PDGF receptor alpha is not sufficient for mitogenesis and migration in mesangial cells

BACKGROUND: Platelet-derived growth factor (PDGF) isoforms act through two distinct cell surface alpha and beta receptors. Glomerular mesangial cells express both receptors. PDGF BB and AB are potent mitogens for glomerular mesangial cells, and PDGF BB stimulates cell migration in a phosphatidylinositol 3 (PI 3) kinase-dependent manner. In this study, we investigated the effect of PDGF AA on cell migration, PI 3 kinase and phospholipase C (PLC) activation, and the role of these two enzymes in mediating biological responses in these cells in response to all three isoforms. METHODS: 3H-thymidine incorporation and modified Boyden chamber assay were used to determine DNA synthesis and directed migration, respectively, in response to all three PDGF isoforms. Differential activation of alpha and beta receptors was studied by immunecomplex tyrosine kinase assay of corresponding receptor immunoprecipitates. PLC gamma 1 activity was determined by measuring total inositol phosphates in response to different PDGF isoforms. PI 3 kinase activity was determined in antiphosphotyrosine or PDGF receptor immunoprecipitates. RESULTS: Both PDGF BB and AB resulted in stimulation of DNA synthesis and directed migration of mesangial cells. AA was neither chemotactic nor mitogenic. However, all three isoforms increased tyrosine phosphorylation of a 180 kD protein in antiphosphotyrosine immunoprecipitates, suggesting activation of respective receptors. Direct immunecomplex tyrosine kinase assay of alpha and beta receptors demonstrated significant activation of both of these receptors when cells are treated with PDGF BB or AB. PDGF AA increased tyrosine kinase activity of the alpha receptor but not the beta receptor. All three isoforms significantly stimulated the production of inositol phosphates with order of potency being BB > AB > AA. PDGF AA also dose dependently stimulated PI 3 kinase activity measured in antiphosphotyrosine immunoprecipitates of treated cells. A comparison of PI 3 kinase activity in antiphosphotyrosine immunoprecipitates from mesangial cells stimulated with three different PDGF isoforms showed significant activation of this enzyme with a decreasing order of activity: BB > AB > AA. CONCLUSION: Taken together, these data demonstrate that all three isoforms of PDGF significantly stimulate PLC gamma 1 and PI 3 kinase, two enzymes necessary for both DNA synthesis and directed migration. However, activation of alpha receptor by PDGF AA with a subsequent increase in PLC and PI 3 kinase activities is not sufficient to induce these biological responses in mesangial cells. These data indicate that the extent of activation of signal transduction pathways may be a major determinant of the biological activity of different PDGF isoforms in mesangial cells.     

Trauma-hemorrhage delays wound healing potentially by increasing pro-inflammatory cytokines at the wound site.

BACKGROUND: Studies indicate impaired wound healing after trauma. The underlying mechanism remains unknown. METHODS: Mice were subjected to midline laparotomy, and polyvinyl alcohol sponges were implanted subcutaneously before hemorrhage (35 +/- 5 mmHg for 90 minutes, resuscitated) or sham operation. Wound exudate cells from the sponges were harvested on the first, third, and fifth postoperative day and cultured for 24 hours. Interleukin (IL)-1 beta, IL-6, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-2 (MIP-2), and transforming growth factor (TGF)-beta were determined in the supernatants. IL-1 beta and IL-6 were measured in the wound fluid. RESULTS: Hemorrhage decreased collagen deposition in the wound. TGF-beta release was significantly decreased on the first and third postoperative days after hemorrhage, whereas IL-1 beta and IL-6 release was increased at 3 and 5 days after hemorrhage. Similarly, IL-1 beta and IL-6 in the wound fluid were significantly increased at 3 days after hemorrhage. CONCLUSIONS: Because increased levels of pro-inflammatory cytokines and decreased amounts of TGF-beta have been reported to impair the process of wound healing, the increased release of IL-1 beta and IL-6 and the decreased release of TGF-beta after hemorrhage might contribute to the decreased collagen production in those animals. Thus, attempts to locally change the ratio of those cytokines in trauma victims might be useful for improving wound healing in those patients.     

胎儿及成人皮肤创面愈合过程中PDGF和EGF表达的对比性研究

目的 探讨人胎儿和成人皮肤及其创面愈合过程中PDGF和EGF的表达及意义。方法 利用已建立的人胎儿无瘢痕愈合动物模型，获取相应标本，结合临床所取成人皮肤标本，采用免疫组化染色方法，观察PDGF，EGF的表达情况。结果 ①正常胎儿皮肤中未见明显的PDGF阳性染色；创伤后12h、1d的胎儿表皮及真皮浅层可见PDGF的弱阳性表达；创伤后3d、1周的胎儿皮肤中PDGF的表达呈阴性；正常成人皮肤可在成纤维细胞，巨噬细胞及毛细血管见到阳性表达；创伤后表达加强；②正常胎儿皮肤表皮全层和毛囊，皮脂腺及汗腺细胞可见EGF的阳性表达；创伤后的胎儿皮肤中EGF的表达未见到明显变化；正常成人皮肤可见表皮基底层有中度阳性表达，毛囊，汗腺细胞也可见到轻度表达，创伤后表达有所减弱。结论 生长因子在胎儿和成人皮肤创面愈合过程中的差异表达可能是胎儿无瘢痕愈合的重要原因之一。     

Autologous platelet gel fails to show beneficial effects on wound healing after saphenectomy in CABG patients

Wound healing impairment in the leg after removal of the saphenous vein within the framework of a coronary artery bypass graft (CABG) operation represents a clinically significant problem. Patients suffer from this complication, and treatment of the wounds is costly in terms of both time and money. No method is known to date that reliably prevents postoperative wound healing disturbances. The effect of autologous platelet gel to stimulate wound healing is known from various medical disciplines. Within a prospective randomized study, we wanted to determine whether intraoperative use of autologous platelet gel on the leg during a CABG operation could reduce the incidence of postoperative wound healing disturbances. The application group (AG) included 35 patients and was compared to a control group (CG) that also had 35 patients. The platelet gel, as well as the thrombin required to activate the platelets, was prepared from autologous patient blood during the operation. Validation of the platelet gel comprised measurement of the growth factors platelet-derived growth factor AB (PDGF AB) and epidermal growth factor (EGF), as well as the thrombocyte and leukocyte counts. Wound healing was photographically documented after surgery, and the patients were contacted by telephone on day 50 after surgery to obtain information on wound healing status. After cell separation, the platelet count was 1616 +/- 845/microL, which is higher than in whole blood by a factor of 7.1 +/- 2.0, with a platelet yield of 47.0% +/- 13.2%. The PDGF AB concentration after activation of the platelets was raised by a median factor of 158 and EGF by a median factor of 64 compared with whole blood. During the primary clinical stay, no statistically significant differences were recorded in the number of hematomas, postoperative leg swelling, or pain level. Large-area hematomas were less frequent in the application group (AG, 29.4% vs. CG, 60%, p = .007). In the follow-up 51 +/- 9 days after surgery, 17.6% (6/34) of the patients from the AG and 31.4% (11/35) of the patients from the CG showed leg wound healing disturbances (p = .184). Using the cell separation system, a biological product that contains high concentrations of platelets, leukocytes, and growth factors can be prepared reproducibly. Despite optimum application of the autologous platelet gel to the wound, no clinically relevant differences were found between the groups, either during the primary clinic stay or in the follow-up period.     

Biological properties of dehydrated human amnion/chorion composite graft: implications for chronic wound healing

Human amnion/chorion tissue derived from the placenta is rich in cytokines and growth factors known to promote wound healing; however, preservation of the biological activities of therapeutic allografts during processing remains a challenge. In this study, PURION® (MiMedx, Marietta, GA) processed dehydrated human amnion/chorion tissue allografts (dHACM, EpiFix®, MiMedx) were evaluated for the presence of growth factors, interleukins (ILs) and tissue inhibitors of metalloproteinases (TIMPs). Enzyme‐linked immunosorbent assays (ELISA) were performed on samples of dHACM and showed quantifiable levels of the following growth factors: platelet‐derived growth factor‐AA (PDGF‐AA), PDGF‐BB, transforming growth factor α (TGFα), TGFβ1, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), placental growth factor (PLGF) and granulocyte colony‐stimulating factor (GCSF). The ELISA assays also confirmed the presence of IL‐4, 6, 8 and 10, and TIMP 1, 2 and 4. Moreover, the relative elution of growth factors into saline from the allograft ranged from 4% to 62%, indicating that there are bound and unbound fractions of these compounds within the allograft. dHACM retained biological activities that cause human dermal fibroblast proliferation and migration of human mesenchymal stem cells (MSCs) in vitro. An in vivo mouse model showed that dHACM when tested in a skin flap model caused mesenchymal progenitor cell recruitment to the site of implantation. The results from both the in vitro and in vivo experiments clearly established that dHACM contains one or more soluble factors capable of stimulating MSC migration and recruitment. In summary, PURION® processed dHACM retains its biological activities related to wound healing, including the potential to positively affect four distinct and pivotal physiological processes intimately involved in wound healing: cell proliferation, inflammation, metalloproteinase activity and recruitment of progenitor cells. This suggests a paracrine mechanism of action for dHACM when used for wound healing applications.     

Inhibition of cell proliferation by chronic wound fluid

It has been proposed that occlusive wound dressings may enhance chronic wound repair by the stimulatory action of the fluid accumulating beneath the dressings. In this report, we investigated the in vitro proliferative effects of chronic wound fluid obtained from under a polyurethane membrane applied for 24 hours to venous ulcers in the ambulatory setting. By measuring cell counts and DNA synthesis, we found that chronic wound fluid inhibited the proliferation of human dermal fibroblasts (p = 0.008) and failed to stimulate the proliferation of microvascular endothelial cells (p = 0.03) and keratinocytes (p = 0.03). The inhibitory activity of chronic wound fluid on fibroblast proliferation was blocked after the fluid was heated to 100 degrees C, but not 56 degrees C, and was mainly restricted to a fraction of chronic wound fluid enriched in components less than 30 kd in molecular weight (p = 0.028). At concentrations ranging from 1% to 4% and in the presence of serum, chronic wound fluid decreased the viability of fibroblasts, as shown by a decreased ability of the cells to exclude trypan blue (p = 0.02), and the viability of endothelial cells, as shown by an increased release of tritiated adenine (p = 0.03). We conclude that the wound fluid obtained from beneath occlusive dressings applied to chronic wounds inhibits cell proliferation.     

Early postoperative enteral feeding increases anastomotic strength in a peritonitis model

BACKGROUND: Tumor necrosis factor alpha (TNF-alpha) has been shown to decrease collagen synthesis and increase collagenase activity leading to impaired wound healing. Our hypothesis was that immediate postoperative feeding would decrease TNF-alpha, therefore increasing anastomotic healing in a peritonitis model. METHODS: Twelve Sprague-Dawley rats underwent cecal ligation and puncture to induce peritonitis. Six hours after induction of peritonitis an ileocecectomy and ileocolostomy was performed. Group 1 animals (n = 6) had immediate access to food and water, whereas group 2 (n = 6) had free access to water only. At 48 hours, weight loss, nitrogen loss, anastamotic bursting strength (ABS), TNF-alpha, interleukin-6 (IL-6), and IL-10 were measured. RESULTS: Weight loss was similar in the two groups. Group 1 rats had a significantly lower mean TNF-alpha level (17.3 +/- 10 versus 17.3 +/- 10 mcg/Dl, P = 0.05). ABS was also significantly higher in group 1 rats when compared with group 2 rats (81 +/- 34 versus 39 +/- 13 mm HG, P = 0.03). CONCLUSIONS: These data suggest that immediate postoperative feeding results in a beneficial change in the cytokine profile.     

Profiles of matrix metalloproteinases and their tissue inhibitors in intraperitoneal drainage fluid: Relationship to wound healing

Matrix degradation and remodeling occurs during wound healing, thereby aiding tissue repair, angiogenesis, and cell migration. It is dependent on the balance between proteinases and their inhibitors, namely the matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Acute wound fluid samples (n = 58 patients) were collected daily from the intraperitoneal drain placed after colorectal surgery from the first postoperative day until drain removal. Three laboratory techniques were performed: enzyme linked immunosorbent assays (MMP-1, MMP-3, TIMP-1, TIMP-2), gelatinase activity assays (MMP-2, MMP-9), and quenched fluorescent substrate hydrolysis (total MMP activity). Levels were correlated with each postoperative day, wound healing, and surgical outcome (p < 0.05, Spearman's correlation). Significant negative (MMP-9, MMP-3, MMP-8, TIMP-2, total MMP activity) and positive (MMP-2, TIMP-1) correlations were observed with the postoperative day, e.g., total MMP-9: day 1, median, 121 (range, 12-189) ng/ml; day 3, 46 (8-179); day 5, 31 (0-155), day 7, 20 (6-58). Differences were also observed with the type of operation, estimated blood loss, and length of operation and with postoperative complications. MMPs and TIMPs are involved in wound healing after elective colorectal cancer surgery and their levels in drain fluid may act as markers of wound healing and surgical outcome.     

Hyaluronic acid in incision wound fluid: A clinical study with the Cellstick® device in children

When inserted into a human incision wound, the Cellstick device harvests inflammatory cells and collects wound fluid, reflecting time-related changes in cell populations and in wound fluid composition. Hyaluronic acid has been postulated to be an important factor in scar reduction in wound healing and in scarless fetal wound healing. The aim of this work was to determine the concentration and variation of hyaluronic acid and proportions of wound cells in closed surgical wounds in children at two time points. The Cellstick device was inserted subcutaneously into the wound at the end of an elective inguinal hernia operation on 37 healthy boys, and the devices were removed 3+/-1 or 24+/-3 hours after surgery. Haluronic acid concentration was measured from the wound fluid and a differential count of the wound cells was performed. There was a significant decrease in hyaluronic acid concentration from 3+/-1 to 24+/-3 hours after surgery (p<0.001, Kruskal-Wallis anova). The variance of hyaluronic acid concentration in wound fluid differed between the wounds at the two time points (p<0.01, Levene test for homogeneity of variance). A positive correlation between hyaluronic acid concentration and patient age (r=0.91, p<0.05, Spearman) at 3+/-1 hours post surgery and between HA and wound lymphocytes (r=0.38, p<0.05, Spearman) was also found. We conclude that the hyaluronic acid concentration in wound fluid peaks early in children and decreases significantly by 3 to 24 hours after surgery, and the concentrations in the wound fluid of healthy boys are more variable 3 hours than at 24 hours after surgery.     

The accelerating effect of negative pressure wound therapy with Prevena™ on the healing of a closed wound with persistent serous secretion

Negative pressure wound therapy has been lately used on closed incisions in the immediate postoperative period to accelerate wound healing. However, there are no data in the literature regarding the use of this type of therapy for wounds with persistent secretion in the early postoperative care. We present the first report of persistent postoperative serous wound secretion in a patient after femoral nailing treated successfully with Prevena? (KCI), a closed incision negative pressure management system (CINPWT).     

Cellular events and biomarkers of wound healing

Researchers have identified several of the cellular events associated with wound healing. Platelets, neutrophils, macrophages, and fibroblasts primarily contribute to the process. They release cytokines including interleukins (ILs) and TNF-α, and growth factors, of which platelet-derived growth factor (PDGF) is perhaps the most important. The cytokines and growth factors manipulate the inflammatory phase of healing. Cytokines are chemotactic for white cells and fibroblasts, while the growth factors initiate fibroblast and keratinocyte proliferation. Inflammation is followed by the proliferation of fibroblasts, which lay down the extracellular matrix. Simultaneously, various white cells and other connective tissue cells release both the matrix metalloproteinases (MMPs) and the tissue inhibitors of these metalloproteinases (TIMPs). MMPs remove damaged structural proteins such as collagen, while the fibroblasts lay down fresh extracellular matrix proteins. Fluid collected from acute, healing wounds contains growth factors, and stimulates fibroblast proliferation, but fluid collected from chronic, nonhealing wounds does not. Fibroblasts from chronic wounds do not respond to chronic wound fluid, probably because the fibroblasts of these wounds have lost the receptors that respond to cytokines and growth factors. Nonhealing wounds contain high levels of IL1, IL6, and MMPs, and an abnormally high MMP/TIMP ratio. Clinical examination of wounds inconsistently predicts which wounds will heal when procedures like secondary closure are planned. Surgeons therefore hope that these chemicals can be used as biomarkers of wounds which have impaired ability to heal. There is also evidence that the application of growth factors like PDGF will help the healing of chronic, nonhealing wounds.KEY WORDS: Cytokines, growth factors, matrix metalloproteinases, platelet-derived growth factor, wound healingIn the last 30 or so years, researchers have identified several of the cellular and biochemical events associated with wound healing. The process is becoming clearer, with the understanding of the cells and chemicals that help wounds to heal, and of those that inhibit healing. Investigators are trying to analyze the chemicals in chronic wounds in order to determine their condition and fitness for closure. A major advance is the clinical application of some of these chemicals to improve outcomes in wound healing.In this paper we look at the biology of normal and abnormal healing, see if wounds analysis can predict poor healing, and review some literature on the clinical applications of this knowledge.     

大鼠浅度烫伤创面愈合与相关生长因子及受体的基因表达

目的探讨浅Ⅱ度烧伤创面愈合过程中相关生长因子及其受体的作用。方法采用大鼠浅Ⅱ度烫伤模型,观察了大鼠浅Ⅱ度烫伤后创面愈合过程中组织学、炎性细胞、表皮细胞周期的变化,检测了创面相关生长因子及受体的基因表达。结果炎性细胞到达创面依次为中性粒细胞、巨噬细胞和淋巴细胞;表皮细胞周期变化为伤后３天细胞增殖活跃,伤后７天细胞分裂明显增多;伤后１,３天ＰＤＧＦ（血小板源性生长因子）、ＰＤＧＦＲ（血小板源性生长因子受体）和ＥＧＦＲ（表皮生长因子受体）基因表达明显增强,伤后３,５天ＥＧＦ（表皮生长因子）、ＴＧＦβＲ２（转化生长因子β受体α）基因表达增强,伤后５,７天ＴＧＦβＲ１（转化生长因子β受体１）基因表达增强,伤后７,１０天ＴＧＦβ１（转化生长因子β）基因表达增强。结论烧伤诱导相关生长因子及受体的基因表达,并且具有时相性和可逆性;相关生长因子基因表达与表皮细胞周期间可能存在相互调控作用,生长因子是调控创面愈合的主要因素。     

Functional characterisation of bioactive peptide derived from terrestrial snail Cryptozona bistrialis and its wound‐healing property in normal and diabetic‐induced Wistar albino rats

A peptide might be an exciting biomaterial or template for the development of novel wound‐healing agents. In this report, it was isolated from the terrestrial snail Cryptozona bistrialis by enzymatic digestion and was evaluated for its in vitro wound‐healing activity in NIH/3T3 mouse fibroblasts cell line and in vivo wound‐healing activity in normal and diabetic‐induced Wistar albino rats. The C. bistrialis protein was digested by the papain enzyme, and 21.79 kDa peptide (Cb‐peptide) was purified by reversed‐phase high‐performance liquid chromatography and identified by MALDI (matrix‐assisted laser desorption/ionization)‐TOF analysis. The isolated Cb‐peptide was characterised by various analytical methods. The peptide demonstrated a capacity to prevent the development of pathogenic bacterial and fungal cultures and proved that it promotes significant wound‐healing activity in the wound scratch assay method by rapid cell migration and closure of wound. Isolated Cb‐peptide was lyophilised and formulated to ointment and analysed for in vivo wound‐healing activity in normal and diabetic (alloxan monohydrate)‐induced Wistar albino rats. Cb‐peptide ointment‐treated groups showed a greater degree of wound healing and early and complete period of epithelialisation in normal and diabetic‐induced Wistar albino rats. Cb‐peptide ointment‐treated groups showed significant excision and incision wound‐healing activity. A conclusion was reached that the peptide isolated from C. bistrialis showed greater wound‐healing activity compared with vehicle control and standard control.     

Effect of supplemental ornithine on wound healing

BACKGROUND: Supplemental arginine has been shown to enhance wound healing, in particular collagen synthesis. Ornithine is the main metabolite of arginine in the urea cycle and shares many of the biopharmacologic effects of arginine. The present study examines the effect of ornithine supplementation on wound healing and attempts to describe its possible mechanism. METHODS: Wild type (WT) and iNOS knockout (KO) mice were randomized to receive either normal chow and tap water or chow and water each supplemented with 0.5% ornithine (w/w). All animals underwent a midline dorsal skin incision with implantation of polyvinyl alcohol sponges into subcutaneous pockets. On postoperative day 14 the animals were sacrificed. The dorsal wound was harvested for breaking strength determination while the wound sponges were assayed for hydroxyproline content, total wound fluid amino acid, and nitrite/nitrate (NOx) concentration. RESULTS: Dietary ornithine supplementation enhanced wound breaking strength and collagen deposition in both WT and KO mice. This was accompanied by increased wound fluid proline and ornithine levels but not arginine, citrulline, or NOx levels. CONCLUSIONS: The results from this study demonstrate that ornithine supplementation enhances wound healing in both WT and KO mice. This suggests that ornithine's effect on wound healing is independent of the iNOS pathway.     

Wound fluid amino acid concentrations regulate the effect of epidermal growth factor on fibroblast replication

Growth factors and amino acids (AA) are required for cell proliferation. A comparison of the AA composition of wound fluid (WF) to that of Eagle's medium reveals that AA in WF may be limiting to cell replication. Yet WF supports fibroblast replication and stimulates AA uptake. Epidermal growth factor (EGF) stimulates fibroblast replication and stimulates human wound healing when applied topically. We evaluated the interactions between EGF and AA concentrations found in WF. Wound fibroblasts were cultured in media prepared to mimic the AA concentrations found in WF on days 1, 5, and 10 and in the presence of varying concentrations of EGF. Fibroblasts cultured in all three experimental media showed a dose response to EGF for both tritiated-thymidine uptake (proliferation) and AA uptake. The fibroblast proliferation in response to EGF was augmented by the AA composition of day-5 WF. These data show a dose-dependent effect of EGF on fibroblast replication and AA uptake in the absence of serum that is augmented by the particular AA combination found in day-5 WF and suggests that an optimal physiologic AA profile may aid in EGF stimulation of wound fibroblast replication.     

Involvement of RNA helicase p68 in skin wound healing process in rats

Purpose: RNA helicase p68 plays an important role in organ development and maturation through tuning cell proliferation. However, the character and role of p68 in the whole wound healing process need more study. Methods: First, we characterize expression of p68 in normal rat skin development postnatal. Then, we assayed dynamic change of p68 in rat skin from different stage after injury, and explored the role of p68 in proliferation and migration of three types of wound healing related cells. Results: p68 was down-regulated during skin developmental and maturation process, up-regulated after wound, peaked on day 14 and then significantly decreased. Wound fluid enhanced wound healing related cell proliferation and up-regulated expression of p68. Conversely, reducing p68 expression by RNA interference resulted in significantly slower proliferation and migration. Conclusion: Our results define an important role of RNA helicase p68 in skin wound healing process.     

Pharmacokinetics of cefazolin applied topically to the surgical wound.

Topical application of antibiotics is used in the prophylaxis of postoperative surgical infections. However, whether topically applied antibiotics remain primarily in the surgical wound fluid or are systemically absorbed is uncertain. The pharmacokinetics of topically applied cefazolin were studied in a canine model that allowed simultaneous determination of serum and wound fluid antibiotic concentrations. Topical administration of cefazolin resulted in high antibiotic concentrations in the wound fluid for prolonged periods and rapid systemic absorption. Bioavailability after topical administration was 95%. Within 1 hour, the serum concentrations after topical administration equaled the serum concentrations after intravenous administration, and the concentration time curves declined in parallel. In wound fluid, the mean time above the susceptibility break point minimum inhibitory concentration after topical administration of cefazolin was 5.76 hours compared with the estimated time above the minimum inhibitory concentration of 2.55 hours after intravenous administration.