Factors affecting wound healing

Effectiveness of Woven Silk Dressing Materials on Full-skin Thickness Burn Wounds in Rat Model

Purpose:

This study evaluated woven silk textile for burn wound dressing materials in an animal model.

Methods:

Ten rats were used in this experiment. Full-thickness 2×2 cm burn wounds were created on the back of the rats under anesthesia. In the experimental group, the wounds were treated with three different dressing materials from woven silk textile. In the control group, natural healing without any dressing material was set as control. The wound surface area was measured at five days, seven days, and 14 days. Wound healing was evaluated by histologic analysis.

Results:

There were no statistically significant differences among groups at five days post injury. The mean defect size at seven days was largest in Group 3 (462.87 mm²), and smallest in Group 1 (410.89 mm²), not a significant difference (P =0.341). The mean defect size at 14 days was smallest at the Group 3 (308.28 mm²) and largest in the control group (388.18 mm²), not a significant difference (P =0.190). The denuded area was smaller in Group 1 (84.57 mm²) and Group 2 (82.50 mm²) compared with the control group (195.93 mm²), not statistically significant differences (P =0.066, 0.062). The difference between Group 3 and control was also not statistically significant (P =0.136). In histologic analysis, the experimental groups re-epithelialized more than control groups. No evidence was found of severe inflammation.

Conclusion:

The healing of burn wounds was faster with silk weave textile more than the control group. There was no atypical inflammation with silk dressing materials. In conclusion, silk dressing materials could be used to treat burn wounds.

Wound healing activity of a collagen-derived cryptic peptide

Wound healing involves a well-controlled series of interactions among cells and several mediators leading to the restoration of damaged tissue. Degradation of the extracellular matrix (ECM) protein collagen during remodelling of wound tissue leads to the release of bioactive peptides that can possibly influence the healing process. The RGD-containing, antioxidative collagen peptide E1 isolated in an earlier work was screened in this study for its ability to influence multiple steps of the wound healing process. E1 was assayed for and found to be chemotactic. Excision and incision wounds were created on separate groups of rats and E1 was administered topically. The wound tissues were isolated on the 4th and 8th days post-wound and subjected to biochemical and biophysical analysis. A significant decrease in lipid peroxides in the treatment group confirmed the in vivo antioxidant capacity of E1. The treatment group also displayed significant increase in total protein, collagen and amino sugar synthesis indicating faster ECM formation. The significantly increased rate of wound contraction and reepithelialisation along with higher tensile strength of the wound tissue corroborated the results of biochemical analysis. The results confirm the significant role played by collagen peptides in accelerating the healing process and justify their possible use as a pharmaceutical agent.

Absence of CD4 or CD8 lymphocytes changes infiltration of inflammatory cells and profiles of cytokine expression in skin wounds, but does not impair healing

The involvement of lymphocytes in skin wound healing has not been studied extensively. This study shows that CD4 and CD8 cells are present in significant numbers in skin wounds with peak levels at days 5-10 and 7-10, respectively. Both subsets expressed inflammatory and/or regulatory cytokines. To examine the function of CD4 and CD8 lymphocytes in tissue repair, wound healing was examined in mice deficient for either CD4 or CD8 cells. Wounds in CD4 deficient mice exhibited an initial delayed infiltration of CD8 cells followed by a relative increase in CD8 cells at day 10 and thereafter. Wounds in CD4 deficient mice also displayed up-regulated expression of IL1β, IL-6, IL-17, IFN-γ, CXCL-1 and down-regulated expression of IL-4 as compared to wild-type mice. In contrast, wounds in CD8 deficient mice showed significantly decreased infiltration of CD4+ cells, neutrophils, and macrophages along with down-regulated expression of IL1β, IL-6, TNF-α, CXCL-1, CCL-2 and up-regulated expression of IL-4 as compared to wild-type mice. Despite these significant changes in cytokine expression and inflammatory cell infiltrate, the rate of wound closure, wound breaking strength, collagen content and angiogenesis in either CD4 or CD8 deficiency showed no significant difference from that of wild-type mice. The results suggest that, despite being present and involved in wound inflammation, neither CD4+ nor CD8+ cells play critical roles in the healing process of skin wounds. Further studies are needed to investigate whether these cells might play critical roles in wounds that experience stress such as ischemia or infection.

Nutritional status in patients with cutaneous leishmaniasis and a study of the effects of zinc supplementation together with antimony treatment

BACKGROUND

The role of micronutrient status for the incidence and clinical course of cutaneous leishmaniasis is not much studied. Still zinc supplementation in leishmaniasis has shown some effect on the clinical recovery, but the evidence in humans is limited.

OBJECTIVE

To compare biochemical nutritional status in cutaneous leishmaniasis patients with that in controls and to study the effects of zinc supplementation for 60 days.

DESIGN

Twenty-nine patients with cutaneous leishmaniasis were treated with antimony for 20 days. Fourteen of them got 45 mg zinc daily and 15 of them got placebo. Biomarkers of nutritional and inflammatory status and changes in size and characteristics of skin lesions were measured.

RESULTS

The level of transferrin receptor was higher in patients than in controls but otherwise no differences in nutritional status were found between patients and controls. No significant effects of zinc supplementation on the clinical recovery were observed as assessed by lesion area reduction and characteristics or on biochemical parameters.

CONCLUSIONS

It is concluded that nutritional status was essentially unaffected in cutaneous leishmaniasis and that oral zinc supplementation administered together with intramuscular injection of antimony had no additional clinical benefit.

Micronutrients, Arginine, and Glutamine: Does Supplementation Provide an Efficient Tool for Prevention and Treatment of Different Kinds of Wounds?

Significance: Wound-healing complications are a clinical problem with a considerable socioeconomic burden. Since several nutrients play a physiological role in wound healing, supplementation of these nutrients may improve wound healing. Recent Advances: Oral nutritional supplements and enteral formulas providing arginine, glutamine, and micronutrients such as ascorbic acid and zinc should improve the healing of pressure ulcers (PU) and the healing of surgical, traumatic, and burned wounds. Is their efficacy proved from clinical intervention trials? Critical Issues: Formulas that are rich in energy, protein, arginine, vitamin C, and zinc can improve PU healing, whereas their efficacy for PU prevention is less clear. High-dose supplementation of vitamin C, zinc, and pantothenic acid may improve the healing of surgical wounds in healthy subjects. Arginine lowers the risk of fistulas in patients undergoing elective surgery due to gastrointestinal cancer. However, formulations also enriched with n-3-fatty acids and ribonucleic acids lower the risk of several wound complications, thus being more effective than isolated arginine. Glutamine and antioxidant micronutrients (vitamin C and E, zinc, selenium, and copper) can improve the healing of surgical, traumatic, and burned wounds. Future Directions: Considerable evidence suggests that formulations, indicated especially for critically ill patients, support the healing of PU and the healing of surgical and burned wounds. However, their optimal composition with regard to the dose of individual components has to be determined in future studies. Further well-designed trials should investigate the impact of certain nutrients for the prevention of PU and for the healing of surgical wounds in healthy subjects.

Rhelogical, dermal wound healing and in vitro antioxidant properties of exopolysaccharide hydrogel from Pseudomonas stutzeri AS22

The in vitro antioxidant activity and the in vivo wound healing performance of the exopolysaccharide EPS22, produced by Pseudomonas stutzeri AS22, were investigated. Antioxidant activity was evaluated by three different tests. The scavenging effect on DPPH radicals at a concentration of 1mg/ml was 80±1.41%. The reducing power reached a maximum of 1.26±0.02 at 2 mg/ml. Moreover, EPS22 showed good chelating ability and chelated almost 88.5±0.7% of ferrous ions at 0.75 mg/ml. The rheological characterization of EPS22 gel (0.5%) showed a pseudoplastic behavior, high elasticity, good mechanical strength and stability with high water-absorption ability. The application of the EPS22 gel on dermal full-thickness excision wounds in a rat model every two days, enhanced significantly wound healing activity and a total closure was achieved after 12 days of wound induction. Further, histological examination of biopsies showed advanced tissue regeneration, characterized by the presence of well-organized stratum of both derma and epidermis.

The regenerative potential of epithelial stem cells in tissue repair

Acute and chronic wounds encompass devastating injuries with significant physical, emotional and economic costs at both the individual and societal level. The pathogenesis of chronic wounds is as varied as the potential causes; however, contributing factors include repetitive ischaemia/reperfusion injury coupled with bacterial infection, inflammation and matrix degradation at the wound site. Similarly, the acute physical damage of burns may leave patients vulnerable to dehydration and infection, and in certain cases this may be followed by a body-wide systemic response with debilitating consequences. Epithelial stem cells provide a promising avenue for the treatment of burns and chronic wounds. This is exemplified by recent achievements such as the restoration of corneal epithelium using limbal stem cells, and the treatment of epidermolysis bullosa via a gene therapy approach. Nevertheless, many technical and regulatory challenges remain to be addressed. This article is part of a Directed Issue entitled: Regenerative Medicine: the challenge of translation.

Efficacy of short novel antimicrobial and anti-inflammatory peptides in a mouse model of methicillin-resistant Staphylococcus aureus (MRSA) skin infection

The therapeutic efficacy of two novel short antimicrobial and anti-inflammatory peptides (RR and RRIKA) was evaluated in a mouse model of staphylococcal skin infection. RR (2%) and RRIKA (2%) significantly reduced the bacterial counts and the levels of proinflammatory cytokines, tumor necrosis factor (TNF)-α, and interleukin (IL)-6, in methicillin-resistant Staphylococcus aureus USA 300-0114 skin lesions. Furthermore, the combined therapy of RRIKA (1%) and lysostaphin (0.5%) had significantly higher antistaphylococcal and anti-inflammatory activity compared to monotherapy. This study supports the potential use of these peptides for topical treatment of methicillin-resistant Staphylococcus aureus skin infections.

Bariatric surgery outcomes in patients with systemic lupus erythematosus

BACKGROUND

Obesity is common among systemic lupus erythematosus (SLE) patients. An increased perioperative risk after major surgery in SLE has been reported. The aim of this study was to describe postoperative outcomes among SLE patients undergoing bariatric surgery.

METHODS

Charts were reviewed to identify patients with an active diagnosis of SLE before bariatric surgery. Demographic variables, perioperative data, and SLE-related parameters were extracted.

RESULTS

Thirty-one morbidly obese patients who underwent bariatric surgery between 2005 and 2013 had a SLE diagnosis. Twenty-three patients had laparoscopic Roux-en-Y gastric bypass (RYGBP), 3 underwent laparoscopic revisional surgery for failed bariatric procedure, 3 had laparoscopic sleeve gastrectomy and 1 underwent laparoscopic adjustable gastric banding. Mean age, body mass index, and excess weight (kg) at baseline were 52.8±9.4 years, 44.3±9 kg/m(2), and 52.5±25.7 kg, respectively. Of these 31 patients, 24 (77.4%) were taking immunosuppressive medications at the time of surgery. Early major postoperative complications occurred in 4 patients (12.9%), with 3 requiring reoperation (9.6%). Multivariate analysis identified immunosuppressive therapy to be significantly associated with postoperative complications (P = .05). At a mean follow-up of 3 years, 13 patients (42%) showed reduction in the number of immunosuppressive medications and 6 (19.3%) were off steroids completely. After bariatric surgery, mean body mass index decreased to 34.2±8.2 kg/m(2) (P<.005) and excess weight loss was 51.2%± 33.4%.

CONCLUSION

Results suggest that weight loss after bariatric surgery is associated with decreased SLE immunosuppression medication requirements; however, the risks are higher. Bariatric surgery in this patient population should be approached with caution.

A novel model of chronic wounds: importance of redox imbalance and biofilm-forming bacteria for establishment of chronicity

Chronic wounds have a large impact on health, affecting ∼6.5 M people and costing ∼$25B/year in the US alone. We previously discovered that a genetically modified mouse model displays impaired healing similar to problematic wounds in humans and that sometimes the wounds become chronic. Here we show how and why these impaired wounds become chronic, describe a way whereby we can drive impaired wounds to chronicity at will and propose that the same processes are involved in chronic wound development in humans. We hypothesize that exacerbated levels of oxidative stress are critical for initiation of chronicity. We show that, very early after injury, wounds with impaired healing contain elevated levels of reactive oxygen and nitrogen species and, much like in humans, these levels increase with age. Moreover, the activity of anti-oxidant enzymes is not elevated, leading to buildup of oxidative stress in the wound environment. To induce chronicity, we exacerbated the redox imbalance by further inhibiting the antioxidant enzymes and by infecting the wounds with biofilm-forming bacteria isolated from the chronic wounds that developed naturally in these mice. These wounds do not re-epithelialize, the granulation tissue lacks vascularization and interstitial collagen fibers, they contain an antibiotic-resistant mixed bioflora with biofilm-forming capacity, and they stay open for several weeks. These findings are highly significant because they show for the first time that chronic wounds can be generated in an animal model effectively and consistently. The availability of such a model will significantly propel the field forward because it can be used to develop strategies to regain redox balance that may result in inhibition of biofilm formation and result in restoration of healthy wound tissue. Furthermore, the model can lead to the understanding of other fundamental mechanisms of chronic wound development that can potentially lead to novel therapies.

A bioactive molecule in a complex wound healing process: platelet-derived growth factor

Wound healing is considered to be particularly important after surgical procedures, and the most important wounds related to surgical procedures are incisional, excisional, and punch wounds. Research is ongoing to identify methods to heal non-closed wounds or to accelerate wound healing; however, wound healing is a complex process that includes many biological and physiological events, and it is affected by various local and systemic factors, including diabetes mellitus, infection, ischemia, and aging. Different cell types (such as platelets, macrophages, and neutrophils) release growth factors during the healing process, and platelet-derived growth factor is a particularly important mediator in most stages of wound healing. This review explores the relationship between platelet-derived growth factor and wound healing.

Effects of energy drinks on soft tissue healing

The aim of the present study was to investigate the effects of an energy drink (ED) on soft tissue wound healing in the rat model. Thirty-six male Wistar albino rats were randomly divided into 2 groups. A full-thickness paravertebral linear incision wound model was created. The experimental group (EG) received an ED (Red Bull), and the control group (CG) received water. Red Bull (3.57 mL/kg/d) was administered to the rats by the oral gavage method on the day before the skin incision and continued for 14 days. The rats were sacrificed (n = 6 in each group) on the 3rd, 7th, and 14th day of the study. Sections were obtained from excised linear wound healing site and stained with hematoxylin-eosin and Masson trichrome for morphological analysis. To assess angiogenesis on the sections, immunohistochemical studies were carried out using vascular endothelial growth factor antibody and alpha smooth muscle actin Ab-1. The breaking strength of the wound healing site was measured in Newtons using a tensiometer. Morphological analysis showed that collagen deposition in the wound areas was statistically higher in the EG compared with that of the CG at both the third and seventh days (P < 0.05). Re-epithelialization on healing sites in the EG was statistically higher than in the CG on the seventh day (P < 0.05). The results of the immunohistochemical studies indicated that the numbers of new blood vessels in the wound healing sites of the EG were significantly higher at the 7th and 14th days when compared with the CG (P < 0.05). The breaking strength of the wound healing sites was also significantly higher on the 7th and 14th days in the EG (P < 0.05). The results demonstrate that ED accelerates soft tissue wound healing and that its effect may be due to increased collagen deposition, re-epithelialization, and new blood vessel formation in the wound.

Hypoxia-sensitive pathways in inflammation-driven fibrosis

Tissue injury can occur for a variety of reasons, including physical damage, infection, and ischemia. The ability of tissues to effectively recover from injury is a cornerstone of human health. The healing response in tissues is conserved across organs and typically involves distinct but overlapping inflammatory, proliferative, and maturation/resolution phases. If the inflammatory phase is not successfully controlled and appropriately resolved, an excessive healing response characterized by scar formation can lead to tissue fibrosis, a major clinical complication in disorders such as Crohn's disease (CD). As a result of enhanced metabolic and inflammatory processes during chronic inflammation, profound changes in tissue oxygen levels occur leading to localized tissue hypoxia. Therefore, inflammation, fibrosis, and hypoxia are coincidental events during inflammation-driven fibrosis. Our current understanding of the mechanism(s) underpinning fibrosis is limited as are the therapeutic options available. In this review, we discuss what is known about the cellular and molecular mechanisms underpinning inflammation-driven fibrosis and how hypoxia may play a role in shaping this process.

The Effects of Oltipraz on Tissue Regeneration in the Process of Wound Healing: A Stereological Study

OBJECTIVE

To determine the effects of topical administration of 20% oltipraz solution on histomorphometrical and stereological aspects of skin tissue in full thickness skin wounds in laboratory rats.

METHODS

Thirty-six male Wistar portion rats (220±20 g) were randomly divided into three groups (n=12). On the first day of experimentation, a 1-cm2 circular wound was made on the posterior surface of neck in all rats by removing a full thickness skin piece immediately after induction of anesthesia with ether inhalation. One group was treated with vehicle solution (DMSO alone). The second group was treated daily with 20% oltipraz solution, and the third group, the control group, received no treatment. The wound closure rate was estimated our previously described method. The volume density of collagen bundles, vessels, and hair follicles, the vessels' length density, mean diameter of vessels and also fibroblast population were estimated by using stereological methods.

RESULTS

The oltipraz group indicated a significantly higher improvement (6.26% of the wound surface per day) than control and the vehicle treated groups (p=0.032); furthermore, there was inconsiderable difference between the rate of wound closure in the group treated with vehicle (4.93% per day) and the control group (4.43% per day).

CONCLUSION

Oltipraz  has  positive  influence on  fibroblast proliferation  and  re-pithelization.  A  noticeable observation in our study was absence of scar formation in wounds which were treated by oltipraz and can be mentioned as an advantage of this drug.

Multifunctional skin-like electronics for quantitative, clinical monitoring of cutaneous wound healing

Non-invasive, biomedical devices have the potential to provide important, quantitative data for the assessment of skin diseases and wound healing. Traditional methods either rely on qualitative visual and tactile judgments of a professional and/or data obtained using instrumentation with forms that do not readily allow intimate integration with sensitive skin near a wound site. Here, an electronic sensor platform that can softly and reversibly laminate perilesionally at wounds to provide highly accurate, quantitative data of relevance to the management of surgical wound healing is reported. Clinical studies on patients using thermal sensors and actuators in fractal layouts provide precise time-dependent mapping of temperature and thermal conductivity of the skin near the wounds. Analytical and simulation results establish the fundamentals of the sensing modalities, the mechanics of the system, and strategies for optimized design. The use of this type of "epidermal" electronics system in a realistic clinical setting with human subjects establishes a set of practical procedures in disinfection, reuse, and protocols for quantitative measurement. The results have the potential to address important unmet needs in chronic wound management.

Tissue injury and hypoxia promote malignant progression of prostate cancer by inducing CXCL13 expression in tumor myofibroblasts

Prostate cancer (PC) is a slowly progressing malignancy that often responds to androgen ablation or chemotherapy by becoming more aggressive, acquiring a neuroendocrine phenotype, and undergoing metastatic spread. We found that B lymphocytes recruited into regressing androgen-deprived tumors by C-X-C motif chemokine 13 (CXCL13), a chemokine whose expression correlates with clinical severity, play an important role in malignant progression and metastatic dissemination of PC. We now describe how androgen ablation induces CXCL13 expression. In both allografted and spontaneous mouse PC, CXCL13 is expressed by tumor-associated myofibroblasts that are activated on androgen ablation through a hypoxia-dependent mechanism. The same cells produce CXCL13 after chemotherapy. Myofibroblast activation and CXCL13 expression also occur in the normal prostate after androgen deprivation, and CXCL13 is expressed by myofibroblasts in human PC. Hypoxia activates hypoxia-inducible factor 1 (HIF-1) and induces autocrine TGF-β signaling that promotes myofibroblast activation and CXCL13 induction. In addition to TGF-β receptor kinase inhibitors, myofibroblast activation and CXCL13 induction are blocked by phosphodiesterase 5 (PDE5) inhibitors. Both inhibitor types and myofibroblast immunodepletion block the emergence of castration-resistant PC in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model of spontaneous metastatic PC with neuroendocrine differentiation.

Expression and integrity of dermatopontin in chronic cutaneous wounds: a crucial factor in impaired wound healing

Chronic cutaneous wound (CCW) is a major health care burden wherein the healing process is slow or rather static resulting in anatomical and functional restriction of the damaged tissue. Dysregulated expression and degradation of matrix proteins, growth factors and cytokines contribute to the disrupted and uncoordinated healing process of CCW. Therefore, therapeutic approaches for effective management of CCW should be focused towards identifying and manipulating the molecular defects, such as reduced bioavailability of the pro-healing molecules and elevated activity of proteases. This study essentially deals with assessing the expression and integrity of an extracellular matrix protein, Dermatopontin (DPT), in CCW using real-time quantitative reverse transcriptase PCR and immunological techniques. The results indicate that, despite DPT's high mRNA expression, the protein levels are markedly reduced in both CCW tissue and its exudate. To elucidate the cause for this contradiction in mRNA and protein levels, the stability of DPT is analyzed in the presence of wound exudates and various proteases that are naturally elevated in CCW. DPT was observed to be degraded at higher rates when incubated with certain recombinant proteases or chronic wound exudate. In conclusion, the susceptibility of DPT protein to specific proteases present at high levels in the wound milieu resulted in the degradation of DPT, thus leading to impaired healing response in CCW.

Oxygen supersaturated fluid using fine micro/nanobubbles

Microbubbles show peculiar properties, such as shrinking collapse, long lifetime, high gas solubility, negative electric charge, and free radical production. Fluids supersaturated with various gases can be easily generated using microbubbles. Oxygen microbubble fluid can be very useful for oxygen delivery to hypoxic tissues. However, there have been no reports of comparative investigations into adding fluids containing oxygen fine micro/nanobubbles (OFM-NBs) to common infusion solutions in daily medical care. In this study, it was demonstrated that OFMNBs can generate oxygen-supersaturated fluids, and they may be sufficiently small to infuse safely into blood vessels. It was found that normal saline solution is preferable for generating an oxygen-rich infusion fluid, which is best administered as a 30-minute intravenous infusion. It was also concluded that dextran solution is suitable for drug delivery substances packing oxygen gas over a 1-hour intravenous infusion. In addition, normal saline solution containing OFMNBs was effective for improving blood oxygenation. Thus, the use of OFMNB-containing fluids is a potentially effective novel method for improving blood oxygenation in cases involving hypoxia, ischemic diseases, infection control, and anticancer chemoradiation therapies.

Salamander regeneration as a model for developing novel regenerative and anticancer therapies

Among vertebrates, urodele amphibians are the only tetrapods with the ability to regenerate complex structures such as limbs, tail, and spinal cord throughout their lives. Furthermore, the salamander regeneration process has been shown to reverse tumorigenicity. Fibroblasts are essential for salamander regeneration, but the mechanisms underlying their role in the formation of a regeneration blastema remain unclear. Here, I review the role of fibroblasts in salamander limb regeneration and how their activity compares with that of human fibroblasts. In addition, the question of whether salamander blastema tissue could induce regeneration and tumor regression in animals with a limited regeneration ability is discussed. A deeper understanding of these processes may lead to the development of novel regenerative and anticancer therapies.

Outcomes of immediate perforator flap reconstruction after skin-sparing mastectomy following neoadjuvant chemotherapy

BACKGROUND

The impact of neoadjuvant chemotherapy (NACT) on immediate free flap breast reconstruction remains controversial. Furthermore, the oncological outcomes of immediate free flap breast reconstruction after skin-sparing mastectomy (SSM) following NACT remain unclear. This study aimed to investigate the surgical complications and oncological outcomes of immediate perforator flap reconstruction after SSM following NACT.

METHODS

A total of 201 consecutive patients with indications for immediate perforator flap reconstruction after SSM were included between 2004 and 2012. Surgical and oncological outcomes were compared between patients with and without NACT.

RESULTS

There were 38 patients in the NACT group and 163 in the non-NACT control group. The median age of the NACT group was 39.5 years, which was significantly younger than the control group (43.0 years; P < 0.05). Patients in the NACT group also had more advanced and aggressive disease (P < 0.05). There was no significant difference in the frequency of surgical complications between the groups, no difference in the type of complications, and no significant difference in the frequencies of major and minor complications. No patients in the NACT group had delayed adjuvant therapy. Eight patients (4%) developed recurrences, with a median follow-up time of 3.0 years. Local recurrences occurred in three control patients but no patients in the NACT group.

CONCLUSION

NACT does not affect short-term or interim outcomes after immediate perforator flap reconstruction and may thus represent a safe and practical treatment option for the multidisciplinary treatment of breast cancer.

A short peptide from frog skin accelerates diabetic wound healing

Delayed wound healing will result in the development of chronic wounds in some diseases, such as diabetes. Amphibian skins possess excellent wound-healing ability and represent a resource for prospective wound-healing promoting compounds. A potential wound-healing promoting peptide (CW49; amino acid sequence APFRMGICTTN) was identified from the frog skin of Odorrana grahami. It promotes wound healing in a murine model with a full-thickness dermal wound in both normal and diabetic animals. In addition to its strong angiogenic ability with respect to the upregulation of some angiogenic proteins, CW49 also showed a significant anti-inflammatory effect in diabetic wounds, which was very important for healing chronic wounds. CW49 had little effect on re-epithelialization, resulting in no significant effect on wound closure rate compared to a vehicle control. Altogether, this indicated that CW49 might accelerate diabetic wound healing by promoting angiogenesis and preventing any excessive inflammatory response. Considering its favorable traits as a small peptide that significantly promotes angiogenesis, CW49 might be an excellent candidate or template for the development of a drug for use in the treatment of diabetic wounds.

Comparative Evaluation of Midventral and Flank Laparotomy Approaches in Goat

The aim of the study was to compare two laparotomy approaches (flank and midventral). Ten (n = 10) apparently healthy goats of different breeds and sex, average age of 12 ± 2.1 months, and average weight of 13.4 ± 2 kg were used for the investigation. The goats were randomly divided into flank and midventral groups, each group comprising five goats (n = 5). Standard aseptic laparotomy was performed under lumbosacral epidural anaesthesia with mild sedation. Postsurgical wound score showed significant difference (P < 0.05) in erythema at 18–24 hours and 10–14 days after surgery between the two approaches; significant difference of dehiscence between the two groups was also recorded at 10–14 days after surgery. Total white blood cells (WBC) and lymphocytes counts were significantly different (P < 0.05) at the first and second week after surgery. There was significant difference of platelets critical value and platelets dimension width at the first and second week after surgery. Significant difference of packed cells volume between the two approaches was also recorded one week after surgery. It was concluded that midventral laparotomy approach can be conveniently and safely performed under aseptic precautions without fear of intra- and postoperative clinical problems.

Diabetic foot ulcers: evaluation and management

Diabetic foot ulcers (DFUs) are a common complication of diabetes and present a significant health risk to patients, as well as impose a large economic burden. Evaluation for contributory factors that may impact general health or healing, such as hyperglycemia, peripheral artery disease, neuropathy, and nutritional status, is of the utmost importance. Management of DFUs requires involvement of a multidisciplinary team and a standardized approach to patient care. Standard therapy for DFUs includes offloading and debridement. Assessment and control of infection are critical, including determining the severity of the infection, which may drive therapeutic approaches. For recalcitrant ulcers, adjuvant therapies are used to hasten the healing process, and newer therapies are under investigation.

PDGF-BB does not accelerate healing in diabetic mice with splinted skin wounds

Topical application of platelet-derived growth factor-BB (PDGF-BB) is considered to accelerate tissue repair of impaired chronic wounds. However, the vast literature is plagued with conflicting reports of its efficacy in animal models and this is often influenced by a wide array of experimental variables making it difficult to compare the results across the studies. To mitigate the confounding variables that influence the efficacy of topically applied PDGF-BB, we used a controlled full thickness splinted excisional wound model in db/db mice (type 2 diabetic mouse model) for our investigations. A carefully-defined silicone-splinted wound model, with reduced wound contraction, controlled splint and bandage maintenance, allowing for healing primarily by reepithelialization was employed. Two splinted 8 mm dorsal full thickness wounds were made in db/db mice. Wounds were topically treated once daily with either 3 µg PDGF-BB in 30 µl of 5% PEG-PBS vehicle or an equal volume of vehicle for 10 days. Body weights, wound contraction, wound closure, reepithelialization, collagen content, and wound bed inflammation were evaluated clinically and histopathologically. The bioactivity of PDGF-BB was confirmed by in vitro proliferation assay. PDGF-BB, although bioactive in vitro, failed to accelerate wound healing in vivo in the db/db mice using the splinted wound model. Considering that the predominant mechanism of wound healing in humans is by re-epeithelialization, the most appropriate model for evaluating therapeutics is one that uses splints to prevent excessive wound contraction. Here, we report that PDGF-BB does not promote wound closure by re-epithelialization in a murine splinted wound model. Our results highlight that the effects of cytoactive factors reported in vivo ought to be carefully interpreted with critical consideration of the wound model used.

The basic science of platelet-rich plasma (PRP): what clinicians need to know

Platelet-rich plasma (PRP) has been advocated for the biological augmentation of tissue healing and regeneration through the local introduction of increased levels (above baseline) of platelets and their associated bioactive molecules. In theory, the increased levels of autologous growth factors and secretory proteins provided by the concentrated platelets may enhance the wound healing process, especially in degenerative tissues or biologically compromised individuals. Although PRP has been increasingly utilized in the treatment of a variety of sports-related injuries, improvements in healing and clinical outcomes have not been universally reported. One reason for this may be the fact that all PRP preparations are not the same. Variations in the volume of whole blood taken, the platelet recovery efficacy, the final volume of plasma in which the platelets are suspended, and the presence or absence of white blood cells, and the addition of exogenous thrombin to activate the platelets or calcium chloride to induce fibrin formation, can all affect the character and potential efficacy of the final PRP product. This article will review the basic principles involved in creating PRP and examine the potential basic scientific significance of the individual blood components contained in the various forms of PRP currently used in sports medicine.

Novel supramolecular elastomer films based on linear carboxyl-terminated polydimethylsiloxane oligomers: preparation, characterization, biocompatibility, and application in wound dressings

A novel supramolecular elastomer (SESi) based on multiple hydrogen bond associations between low-molecular-weight polydimethylsiloxane chains was obtained through a two-step reaction of linear carboxyl-terminated polydimethylsiloxane oligomers with diethylenetriamine and urea, and the reaction mechanism was characterized. The results of differential scanning calorimetry and X-ray diffraction analyses indicated that the supramolecular network structure is completely amorphous, endowing SESi with rubber-like elastic behavior at room temperature. The transparent SESi film prepared by hot pressing displayed nice viscoelasticity, benign water absorption, water vapor transition rates, and ideal biocompatibility; and did not show cytotoxicity or skin irritation. These properties allow the elastomer to function as an occlusive wound dressing. To demonstrate its potential in wound dressings, a detailed comparison of commercial 3M Tegaderm(™) film and the SESi film was conducted. The SESi film exhibited similar effects in wound healing, and the wound bed was covered by the SESi film without the occurrence of significant adverse reactions.

Histopathological comparative analysis of peri-implant soft tissue response after dental implant placement with flap and flapless surgical technique. Experimental study in pigs

AIM

The aim of this study was comparing the effect of flapless vs. flap technique of implant placement on inflammation degree of peri-implant soft tissue, through histopathological analysis.

METHOD

The experiment was conducted on five domestic pigs. Nine weeks after tooth extraction, implants were installed. Each animal received six implants in mandible. According to split-mouth design, randomly one side was used for flapless technique using mini-incision, while on the other side, flap was raised. After 7, 14, 21, 28, and 90 days, the experimental animals were sacrificed. Samples for histopathological analyzes were taken from the buccal side of peri-implant mucosa next to the neck of implants, from three levels. The degree of inflammatory response in the peri-implant soft tissue was estimated through ordinal scores from 0 to 3.

RESULTS

In the flap group Score 3 indicating high degree of inflammation was present from day 7 to day 21, in contrast to flapless group where Score 3 was not recorded during the entire follow-up. Three months after implantation, there were no signs of inflammation neither around flap nor around flapless implants.

CONCLUSION

Flapless surgical implantation technique using mini-incision decreases peri-implant soft tissue inflammatory reaction compared with flap surgery.

Leptin promotes wound healing in the oral mucosa

INTRODUCTION

Leptin, a 16 kDa circulating anti-obesity hormone, exhibits many physiological properties. Recently, leptin was isolated from saliva; however, its function in the oral cavity is still unclear. In this study, we investigated the physiological role of leptin in the oral cavity by focusing on its effect on wound healing in the oral mucosa.

METHODS

Immunohistochemical analysis was used to examine the expression of the leptin receptor (Ob-R) in human/rabbit oral mucosa. To investigate the effect of leptin on wound healing in the oral mucosa, chemical wounds were created in rabbit oral mucosa, and leptin was topically administered to the wound. The process of wound repair was histologically observed and quantitatively analyzed by measuring the area of ulceration and the duration required for complete healing. The effect of leptin on the proliferation, differentiation and migration of human oral mucosal epithelial cells (RT7 cells) was investigated using crystal violet staining, reverse transcription polymerase chain reaction (RT-PCR) and a wound healing assay, respectively.

RESULTS

Ob-R was expressed in spinous/granular cells in the epithelial tissue and vascular endothelial cells in the subepithelial connective tissue of the oral mucosa. Topical administration of leptin significantly promoted wound healing and shortened the duration required for complete healing. Histological analysis of gingival tissue beneath the ulceration showed a denser distribution of blood vessels in the leptin-treated group. Although the proliferation and differentiation of RT7 cells were not affected by leptin, the migration of these cells was accelerated in the presence of leptin.

CONCLUSION

Topically administered leptin was shown to promote wound healing in the oral mucosa by accelerating epithelial cell migration and enhancing angiogenesis around the wounded area. These results strongly suggest that topical administration of leptin may be useful as a treatment to promote wound healing in the oral mucosa.

Comparing the effects of nebivolol and dexpanthenol on wound healing: an experimental study

Wound healing is a dynamic, interactive process that is initiated in response to injury. A number of investigations and clinical studies have been performed to determine new approaches for the improvement of wound healing. The aim of this study was to compare the effects of dexpanthenol, a molecule that is widely used for improving wound healing, and nebivolol, a molecule that increases nitric oxide release, on wound healing. A total of 30 rats were divided into three equal groups (n = 10). A linear 2 cm incision was made in the rats' skin. No treatment was administered in the first (control) group. Dexpanthenol cream was administered to the rats in the second group and 5% nebivolol cream was administered to the rats in the third group. The wound areas of all of the rats were measured on certain days. On the 21(st) day, all wounds were excised and histologically evaluated. The wound healing rates of the dexpanthenol and nebivolol groups were higher than those of the control group (P < 0·05). However, the wound healing rates of the dexpanthenol and nebivolol groups were not significantly different. Nebivolol and dexpanthenol have comparable effects on wound healing.

Cholecystectomy and wound complications: smoking worsens risk

BACKGROUND

In the United States, approximately 800,000 cholecystectomies are performed annually. We sought to determine the influence of preoperative smoking on postcholecystectomy wound complication rates.

MATERIALS AND METHODS

Using the National Surgical Quality Improvement Program database (2005-2011), patients aged ≥18 y who underwent elective open or laparoscopic cholecystectomy (LC) for benign gallbladder disease were identified using current procedural terminology codes. Multivariate regression was performed to determine the association between smoking status and wound complications, by surgical approach.

RESULTS

Of 143,753 identified patients, 128,692 (89.5%) underwent LC, 27,788 (19.3%) were active smokers, and 100,710 (70.2%) were females. Active smokers were younger than nonsmokers (mean + standard deviation age: 44.2 (14.9) versus 51.6 (17.9) years); P < 0.001) and had fewer comorbidities. Within 30-d postcholecystectomy, wound complications were reported in 2011 (1.4%) patients. Compared with nonsmokers, active smokers demonstrated increased odds of wound complications after both open cholecystectomy (odds ratio 1.28; P = 0.010) and LC (odds ratio 1.20; P = 0.020) after adjustment for demographic and clinical characteristics. Having wound complications increased the average postoperative length of stay by 2-4 d (P <0.001).

CONCLUSIONS

Active smokers are more likely to develop wound complications after cholecystectomy, regardless of surgical approach. Occurrence of wound complications consequently increases postoperative length of stay. Smoking abstinence before cholecystectomy may reduce the burden associated with wound complications.

Galectin-1 accelerates wound healing by regulating the neuropilin-1/Smad3/NOX4 pathway and ROS production in myofibroblasts

Myofibroblasts have a key role in wound healing by secreting growth factors and chemoattractants to create new substrates and proteins in the extracellular matrix. We have found that galectin-1, a β-galactose-binding lectin involved in many physiological functions, induces myofibroblast activation; however, the mechanism remains unclear. Here, we reveal that galectin-1-null (Lgals1(-/-)) mice exhibited a delayed cutaneous wound healing response. Galectin-1 induced myofibroblast activation, migration, and proliferation by triggering intracellular reactive oxygen species (ROS) production. A ROS-producing protein, NADPH oxidase 4 (NOX4), was upregulated by galectin-1 through the neuropilin-1/Smad3 signaling pathway in myofibroblasts. Subcutaneous injection of galectin-1 into wound areas accelerated the healing of general and pathological (streptozotocin-induced diabetes mellitus) wounds and decreased the mortality of diabetic mice with skin wounds. These findings indicate that galectin-1 is a key regulator of wound repair that has therapeutic potential for pathological or imperfect wound healing.

Reduced FOXO1 expression accelerates skin wound healing and attenuates scarring

The forkhead box O (FOXO) family has been extensively investigated in aging and metabolism, but its role in tissue-repair processes remains largely unknown. Herein, we clarify the molecular aspect of the FOXO family in skin wound healing. We demonstrated that Foxo1 and Foxo3a were both up-regulated during murine skin wound healing. Partial knockout of Foxo1 in Foxo1(+/-) mice throughout the body led to accelerated skin wound healing with enhanced keratinocyte migration, reduced granulation tissue formation, and decreased collagen density, accompanied by an attenuated inflammatory response, but we observed no wound phenotype in Foxo3a(-/-) mice. Fibroblast growth factor 2, adiponectin, and notch1 genes were significantly increased at wound sites in Foxo1(+/-) mice, along with markedly altered extracellular signal-regulated kinase 1/2 and AKT phosphorylation. Similarly, transient knockdown of Foxo1 at the wound site by local delivery of antisense oligodeoxynucleotides enhanced skin wound healing. The link between FOXO1 and scarring extends to patients, in particular keloid scars, where we see FOXO1 expression markedly increased in fibroblasts and inflammatory cells within the otherwise normal dermis. This occurs in the immediate vicinity of the keloid by comparison to the center of the mature keloid, indicating that FOXO1 is associated with the overgrowth of this fibrotic response into adjacent normal skin. Overall, our data indicate that molecular targeting of FOXO1 may improve the quality of healing and reduce pathological scarring.

Clinical, radiographical, and histological outcomes of plasma rich in growth factors in extraction socket: a randomized controlled clinical trial

OBJECTIVES

Platelet-rich plasma has been used in the treatment of extraction socket; however, randomized controlled clinical trial is still lacking to evaluate its effect on extraction socket healing.

MATERIALS AND METHODS

Single center, assessor-blinded, parallel group, randomized controlled clinical trial was conducted. Sixty patients with indication of a simple one molar extraction in the mandible were randomized to receive plasma rich in growth factors (PRGF) or blood clot. A cross-stitch suture was placed in both groups. Clinical, radiographical, and histological assessments were performed during 10-12 weeks of follow-up.

RESULTS

Cone beam CT analysis has shown that the percentage of patients where the sockets are regenerated at ≥75 % of the baseline volume was significantly higher in PRGF group (96.7 %) than the control group (45.5 %). Pain and inflammation (day 3 and day 7) have been significantly lower in PRGF group than the control group but not at day 15. Soft tissue healing scores have been significantly higher in the test group. No serious adverse events have been occurred in both groups. Histological analysis has indicated the presence of significantly thicker keratinized epithelium and significantly higher newly formed bone in the PRGF group.

CONCLUSIONS

PRGF was associated with enhanced healing of extraction socket of mandibular molars throughout the observation period.

CLINICAL RELEVANCE

Plasma rich in growth factors could be a useful tool to enhance the healing of extraction sockets by minimizing postoperative complications and stimulating the hard and soft tissues regeneration.

Evaluation of the healing activity of therapeutic clay in rat skin wounds

The use of clays for therapeutic practice is widespread in almost all regions of the world. In this study the physicochemical and microbiological healing characteristics of a clay from Ocara, Brazil, popularly used for therapeutic uses, were analyzed. The presence of Ca, Mg, Al, Fe, and Si was observed, which initially indicated that the clay had potential for therapeutic use. The average particle size of the clay (26.3 μm) can induce the microcirculation of the skin and the XRD analysis shows that the clay is formed by kaolinite and illite, a swelling clay. During the microbiological evaluation there was the need to sterilize the clay for later incorporation into the pharmaceutical formula. The accelerated stability test at 50°C for 3 months has showed that the pharmaceutical formula remained stable with a shelf life of two years. After the stability test the wound-healing capacity of the formulation in rats was evaluated. It was observed that the treatment made with the formulation containing the Ocara clay showed the best results since the formula allowed greater formation of collagen fibers and consequent regeneration of the deep dermis after seven days of treatment and reepithelialization and continuous formation of granulation tissue at the 14th day.

Wound healing activity of Origanum vulgare engineered titanium dioxide nanoparticles in Wistar Albino rats

The titanium dioxide nanoparticles (TiO2·NPs) were synthesized utilizing Origanum vulgare under room temperature. The green synthesized TiO2 NPs excitation was confirmed using UV-Vis spectrophotometer at 320 nm. Scanning electron microscopy analysis showed TiO2·NPs are spherical in shape and connected with one another. Dynamic light scattering analysis results specified high stability in nanoparticles, with an average particle size of 341 nm. Fourier transform infrared spectroscopy peaks revealed the presence of bioactive functional groups in Origanum vulgare aqueous leaf extract much needed for the TiO2·NPs formation. X-ray diffraction spectra showed the TiO2·NPs are amorphous in nature. Furthermore, the green synthesized TiO2·NPs wound healing activity was examined in the excision wound model by measuring wound closure, histopathology and protein profiling, revealed significant wound healing activity in Albino rats. In conclusion, our results bared TiO2·NPs have delivered a novel therapeutic route for wound treatment in clinical practice.

Myeloid cell dysfunction and the pathogenesis of the diabetic chronic wound

Diabetes can promote a state of chronic inflammation associated with serious complications that are difficult to treat, including ulceration of the lower extremities and chronic wounds. Chronic wounds are often incurable and contribute to both a reduced quality of life for patients and an enormous burden for healthcare services. In diabetes, the inflammatory response early in wound healing is inappropriately amplified and prolonged, leading to the persistent presence in the wound of vastly elevated numbers of dysfunctional, hyperpolarised macrophages that fail to transition to a pro-healing phenotype. Recent evidence suggests that systemic chronic inflammation induces intrinsic defects in monocytes via chromatin modifications that may pre-programme monocytes to a pro-inflammatory phenotype, while the local wound environment inhibits differentiation to a pro-healing phenotype. Current understanding remains incomplete, and careful dissection of how local and systemic inflammation combine to negatively influence myeloid cell development will be key to developing effective therapies aimed at healing the diabetic wound.

Effect of autologous platelet rich fibrin on the healing of experimental articular cartilage defects of the knee in an animal model

The effect of autologous platelet rich fibrin (PRF), a second generation platelet product, on the healing of experimental articular cartilage lesions was evaluated in an animal model. Full thickness cartilage lesions with a diameter of 6 mm and depth of 5 mm were created in the weight bearing area of femoral condyles of both hind limbs in 12 adult mixed breed dogs. Defects in the left hind limb of each dog were repaired by PRF implantation whereas those in the right hind limb were left empty. The animals were euthanized at 4, 16, and 24 weeks following surgery and the resultant repair tissue was investigated macroscopically and microscopically. The results of macroscopic and histological evaluations indicated that there were significant differences between the PRF treated and untreated defects. In conclusion, the present study indicated that the use of platelet rich fibrin as a source of autologous growth factors leads to improvement in articular cartilage repair.

Efficacy of Annona squamosa L in the synthesis of glycosaminoglycans and collagen during wound repair in streptozotocin induced diabetic rats

The aim of this work was to find out the effects of Annona squamosa on the formation of glycosaminoglycans and collagen during wound healing in normal and diabetic rats. Diabetes induced rats were segregated into 4 groups, each containing six animals. Groups I and III served as the normal and diabetic control while groups II and IV served as normal and diabetic treated. The animals were treated with 200 μL of Annona squamosa extract topically. The granulation tissues formed were removed on the 8th day and the amount of glycosaminoglycans (GAGs) and collagen formed was evaluated by sequential extraction and SDSPAGE, respectively. Histological evaluation was also carried out using Masson's trichrome stain. In vitro wound healing efficacy of A. squamosa in human dermal fibroblast culture (HDF) was also carried out. The fibroblasts treated with varying concentrations of A. squamosa were examined for proliferation and closure of the wound area and photographed. A. squamosa increased cellular proliferation in HDF culture. The granulation tissues of treated wounds showed increased levels of glycosaminoglycans (P < 0.05) and collagen which were also confirmed by histopathology. The results strongly substantiate the beneficial effects of A. squamosa on the formation of glycosaminoglycans and collagen during wound healing.

Powdered Wound Dressing Materials Made from wild Silkworm Antheraea pernyi Silk Fibroin on Full-skin Thickness Burn Wounds on Rats

Purpose:

This study evaluated powdered burn wound dressing materials from wild silkworm fibroin in an animal model.

Methods:

Fifteen rats were used in this experiment. Full-thickness 2×2 cm burn wounds were created on the back of rats under anesthesia. In the two experimental groups, the wounds were treated with two different dressing materials made from silkworm fibroin. In the Control Group, natural healing without any dressing material was set as control. The wound surface area was measured at five days, seven days and 14 days. Wound healing was evaluated by histologic analysis.

Results:

By gross observation, there were no infections or severe inflammations through 14 days post-injury. The differences among groups were statistically significant at seven days and 14 days, postoperatively (P <0.037 and 0.001, respectively). By post hoc test, the defect size was significantly smaller in experimental Group 1 compared with the Control Group and experimental Group 2 at seven days postoperatively (P =0.022 and 0.029, respectively). The difference between Group 1 and Group 2 was statistically significant at 14 days postoperatively (P <0.001). Group 1 and control also differed significantly (P =0.002). Group 1 showed a smaller residual scar than the Control Group and Group 2 at 14 days post-injury. Histologic analysis showed more re-epithelization in Groups 1 and 2 than in the Control Groups.

Conclusion:

Burn wound healing was accelerated with silk fibroin spun by wild silkworm Antheraea pernyi. There was no atypical inflammation with silk dressing materials. In conclusion, silk dressing materials can be used for treatment of burn wound.

Objective assessment of endogenous collagen in vivo during tissue repair by laser induced fluorescence

Collagen, a triple helical protein with the primary role of mechanical function, provides tensile strength to the skin, and plays a pivotal task in tissue repair. During tissue regeneration, collagen level increases gradually and therefore, monitoring of such changes in vivo by laser induced fluorescence was the main objective behind the present study. In order to accomplish this, 15 mm diameter excisional wounds were created on six to eight week old Swiss albino mice. The collagen deposition accelerated upon irradiation of single exposure of 2 J/cm² He-Ne laser dose immediately after wounding was recorded by laser induced autofluorescence in vivo along with un-illuminated and un-wounded controls. Autofluorescence spectra were recorded for each animal of the experimental groups on 0, 5, 10, 30, 45 and 60 days post-wounding, by exciting the granulation tissue/skin with 325 nm He-Cd laser. The variations in the average collagen intensities from the granulation tissue/skin of mice were inspected as a function of age and gender. Further, the spectral findings of the collagen synthesis in wound granulation tissue/un-wounded skin tissues were validated by Picro-Sirius red- polarized light microscopy in a blinded manner through image analysis of the respective collagen birefringence. The in vivo autofluorescence studies have shown a significant increase in collagen synthesis in laser treated animals as compared to the un-illuminated controls. Image analysis of the collagen birefringence further authenticated the ability of autofluorescence in the objective monitoring of collagen in vivo. Our results clearly demonstrate the potential of laser induced autofluorescence in the monitoring of collegen synthesis during tissue regeneration, which may have clinical implications.