Wound Healing: An Overview

Personal Factors that Affect the Satisfaction of Female Patients Undergoing Esthetic Suture after Typical Thyroidectomy

BACKGROUND

In esthetic surgery, understanding the factors that influence patient satisfaction is important for successful practice. We hypothesize that the factors that influence patient satisfaction include not only aesthetic and functional outcomes, but also personal factors such as the level of familiarity with factors affecting wound healing and expectations regarding aesthetic outcome.

METHODS

One hundred patients who underwent esthetic closure after thyroidectomy were included in this study. In order to evaluate the individual characteristics of the patients, a preoperative survey was administered to the patients. We estimated the patient satisfaction six months postoperatively and assessed the aesthetic and functional outcomes using the Patient and Observer Scar Assessment Scale.

RESULTS

According to the results of correlation analysis, level of familiarity with wound healing factors had a positive correlation with satisfaction. High expectations, pain, itching, and high observer scale score had negative correlations with satisfaction. The factors that were correlated with satisfaction were included in the multiple regression analysis. Level of familiarity with wound healing factors was found to have a positive relationship with satisfaction, while itching and observer scale were found to have a negative relationship with satisfaction. After excluding 10 patients who had hypertrophic scars, only level of familiarity with wound healing factors and expectations affected satisfaction.

CONCLUSIONS

The level of familiarity with factors affecting wound healing and expectations were found to independently affect satisfaction. Improving patients' level of familiarity with wound healing factors and reducing their expectations by providing suitable preoperative education has the potential to improve patient satisfaction.

Flap survival after previous vascular pedicle division and preexisting scar formation at the pedicle site: an experimental study

BACKGROUND

We conducted an experimental study to investigate if it would be possible to re-elevate a flap at a standard flap site if its vascular pedicle was mutilated previously and there was a preexisting scar formation at the pedicle site.

MATERIALS AND METHODS

Thirty-five male Sprague-Dawley rats were divided into 3 groups. In the control group (n = 5), animals received a procedure in which unilateral axial pattern abdominal flap was elevated, and then sutured to its original place. The remaining 2 groups underwent 2-stage procedures. In the first stage, scar tissue was created with either a skin incision (group 2, n = 15) or excision (group 3, n = 15) at the prospective pedicle site of the abdominal flap. In the second stage, abdominal flap was raised in 5 rats as a scar-pedicled flap at day 7, day 21, and day 42. Flaps were sutured in their places. Seven days later, flap survival was evaluated.

RESULTS

Control flaps had complete survival (day 7, 95.5%; day 21, 94.8%; and day 42, 94.5%). Group 2 and group 3 flaps raised on day 7 (group 2, 65.4%; group 3, 63.9%) and on day 21 (group 2, 65.7%; group 3, 66.7%) showed decreased survival compared to control group flaps (P < 0.05). On day 42, group 1 flaps had better survival when compared to group 2 flaps (82.6% vs 70.0%, P < 0.05). Group 1 flaps showed progressive vascular network formation as evidenced by contrast medium first in the proximal two thirds of the flaps on day 7, and later via visualization of the axial pattern vascular tree on day 42. In group 3, approximately half of the flap was filled with barium contrast and no single pedicle was identified on day 42.

CONCLUSIONS

Preexisting scar tissue and pedicle division in the pedicle site of a standard flap diminished dimensions of surviving flap when compared to control flaps. Incision-scar-pedicled flaps achieved better survival compared to excision-group flaps, particularly in the late postoperative period. The study findings showed that it may be possible to raise a flap from previously mutilated site secondary to scar formation and pedicle injury.

Elastin signaling in wound repair

Skin is an important organ to the human body as it functions as an interface between the body and environment. Cutaneous injury elicits a complex wound healing process, which is an orchestration of cells, matrix components, and signaling factors that re-establishes the barrier function of skin. In adults, an unavoidable consequence of wound healing is scar formation. However, in early fetal development, wound healing is scarless. This phenomenon is characterized by an attenuated inflammatory response, differential expression of signaling factors, and regeneration of normal skin architecture. Elastin endows a range of mechanical and cell interactive properties to skin. In adult wound healing, elastin is severely lacking and only a disorganized elastic fiber network is present after scar formation. The inherent properties of elastin make it a desirable inclusion to adult wound healing. Elastin imparts recoil and resistance and induces a range of cell activities, including cell migration and proliferation, matrix synthesis, and protease production. The effects of elastin align with the hallmarks of fetal scarless wound healing. Elastin synthesis is substantial in late stage in utero and drops to a trickle in adults. The physical and cell signaling advantages of elastin in a wound healing context creates a parallel with the innate features of fetal skin that can allow for scarless healing.

Enhancement of wound closure in diabetic mice by ex vivo expanded cord blood CD34+ cells

Diabetes can impair wound closure, which can give rise to major clinical problems. Most treatments for wound repair in diabetes remain ineffective. This study aimed to investigate the influence on wound closure of treatments using expanded human cord blood CD34⁺ cells (CB-CD34⁺ cells), freshly isolated CB-CD34⁺ cells and a cytokine cocktail. The test subjects were mice with streptozotocin-induced diabetes. Wounds treated with fresh CB-CD34⁺ cells showed more rapid repair than mice given the PBS control. Injection of expanded CB-CD34⁺ cells improved wound closure significantly, whereas the injection of the cytokine cocktail alone did not improve wound repair. The results also demonstrated a significant decrease in epithelial gaps and advanced re-epithelialization over the wound bed area after treatment with either expanded CB-CD34⁺ cells or freshly isolated cells compared with the control. In addition, treatments with both CB-CD34⁺ cells and the cytokine cocktail were shown to promote recruitment of CD31⁺-endothelial cells in the wounds. Both the CB-CD34⁺ cell population and the cytokine treatments also enhanced the recruitment of CD68-positive cells in the early stages (day 3) of treatment compared with PBS control, although the degree of this enhancement was found to decline in the later stages (day 9). These results demonstrated that expanded CB-CD34⁺ cells or freshly isolated CB-CD34⁺ cells could accelerate wound repair by increasing the recruitment of macrophages and capillaries and the reepithelialization over the wound bed area. Our data suggest an effective role in wound closure for both ex vivo expanded CB-CD34⁺ cells and freshly isolated cells, and these may serve as therapeutic options for wound treatment for diabetic patients. Wound closure acceleration by expanded CB-CD34⁺ cells also breaks the insufficient quantity obstacle of stem cells per unit of cord blood and other stem cell sources, which indicates a broader potential for autologous transplantation.

Compressive properties of fibrous repair tissue compared to nucleus and annulus

The wound healing process includes filling the void between implant and tissue edges by collagenous connective repair tissue. This fibrous repair tissue may load share or stabilize implants such as spinal disc replacements. The objective of this study was the biomechanical characterization of human fibrous tissue compared to annulus fibrosus and nucleus pulposus. Human lumbar discs (10 nucleus and annulus) and 10 lumbar deep wound fibrous tissue specimens were sectioned into 12mm diameter×6mm high cylindrical samples. Confined compression testing, after 2h swelling at 0.11MPa, was performed at 5%, 10% and 15% strain over 3.5h. Unconfined dynamic testing (2-0.001Hz) was performed at 5-15% strain. Semi-quantitative histology estimated the proportion of proteoglycan to collagen. Fibrous tissue exhibited a decrease in height during the swelling period whereas annulus and nucleus tissues did not. The aggregate modulus was significantly less for fibrous tissue (p<0.002). Percent stress relaxation was greatest for the fibrous tissue and similar for annulus and nucleus. Dynamic testing found the storage modulus (E') was greater than the loss modulus (E″) for all tissues. Annulus were found to have greater E' and E″ than nucleus, whereas E' and E″ were similar between annulus and fibrous tissue. Fibrous tissue had the greatest increase in both moduli at greater frequencies, but had the lowest hydration and proteoglycan content. Fibrous tissue would not be a substitute for native tissue within the disc space but if adjacent to a disc prosthesis may impart some degree of intersegmental stability during acute loading activities.

Bride and groom in systemic inflammation--the bells ring for complement and Toll in cooperation

Attenuating the sepsis-induced systemic inflammatory response, with subsequent homeostatic imbalance, has for years been one of the main tasks in sepsis related research. Complement and the TLR family constitute two important upstream sensor and effector-systems of innate immunity. Although they act as partly independent branches of pattern recognition, recent evidence indicate a considerable cross-talk implying that they can either compensate, synergize or antagonize each other. Combined inhibition of these pathways is therefore a particularly interesting approach with a profound anti-inflammatory potential. In previous preclinical studies, we demonstrated that targeting the key molecules C3 or C5 of complement and CD14 of the TLR family had a vast anti-inflammatory effect on Gram-negative bacteria-induced inflammation and sepsis. In this review, we elucidate the significance of these key molecules as important targets for intervention in sepsis and systemic inflammatory response syndrome. Finally, we argue that a combined inhibition of complement and CD14 represent a potential general treatment regimen, beyond the limit of sepsis, including non-infectious systemic inflammation and ischemia reperfusion injury.

Wound management and nutrition for optimal wound healing

The process of wound healing is complicated and requires optimization of wound bed conditions locally through wound management and systemically through proper nutritional care. Although there are a variety of local and systemic factors that can adversely influence healing, the wound environment can be treated through proper dressings to decrease necrotic debris, bacterial load, and foreign bodies. In addition, maintaining or improving patient nutritional status will help the body to supply the necessary building blocks and cellular response for healing to take place.

Aging is associated with increased activities of matrix metalloproteinase-2 and -9 in tenocytes

Background

Most tendon pathology is associated with degeneration, which is thought to involve cyclic loading and cumulative age-related changes in tissue architecture. However, the association between aging and degeneration of the extracellular matrix (ECM) in tendons has not been investigated extensively.

Methods

We examined tenocytes from Achilles tendons taken from rats of three different ages (2, 12, and 24 months). Tenocyte viability was assessed using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Quantitative real-time polymerase chain reaction (PCR) was used to determine the levels of mRNAs that encode type-I collagen, matrix metalloproteinase (MMP)-2 and −9, tissue inhibitor of metalloproteinase (TIMP)-1 and −2 and transforming growth factor (TGF)-β1. Gelatin zymography was used to evaluate the enzymatic activities of MMP-2 and −9. Furthermore, the concentration of TGF-β1 in conditioned medium was evaluated using enzyme-linked immunosorbent assay (ELISA).

Results

The results of the MTT assay showed that the number of viable tenocytes decreased with age. No differences were observed in the levels of mRNAs that encode type-I collagen and TGF-β1 among the three age groups, and the TGF-β1 concentration did not change with age. However, mRNAs that encode MMP-2 and −9 were significantly more abundant in tenocytes from the aging group, and gelatin zymography revealed that the enzymatic activities of MMP-2 and −9 also increased significantly with age. Furthermore, as compared with young group, mRNAs that encode TIMP-1 and −2 were significantly decreased in tenocytes from the aging group.

Conclusions

Activities of MMP-2 and MMP-9 in tenocytes increase with age. This might provide a mechanistic explanation of how aging contributes to tendinopathy or tendon rupture with age.

The influence of peri-incisional triamcinolone acetonide injection on wound edge apposition

Local administration of corticosteroids has been demonstrated to have both beneficial and detrimental effects on wound healing. The advantages of limiting localized edema must be weighed against corticosteroids' disadvantageous inhibition of the normal growth factor profile production that is essential for would healing. A single-center prospective, randomized, controlled, single-blind study of 57 patients undergoing hair restoration surgery (HRS) by one of three different surgeons revealed: 1) no dehiscence along the donor wound; 2) no statistically significant difference (p < 0.05) in wound edge apposition noted between patients receiving or not receiving intralesional corticosteroids at any of the four measured scalp regions and 3) a non-statistically significant trend emerged suggesting the benefit of corticosteroid at the temples (points of decreased donor closing tension) versus its potential hindrance along the mastoids (points of increased tension). These results suggest that peri-incisional triamcinolone acetonide (PITMC) does not have a statistically significant effect on donor wound edge apposition within 8-10 days of HRS. A subtle, though not statistically significant, trend emerged demonstrating the benefit of PITMC with respect to early phase donor wound edge apposition in areas of least donor closing tension and the hindrance of PITMC in regions of increased tension.

Role of stem cells in the management of chronic wounds

Chronic wounds continue to be a major challenge for the medical profession, and plastic surgeons are frequently called in to help in the management of such wounds. Apart from the obvious morbidity to the patient, these problem wounds can be a major drain on the already scarce hospital resources. Sometimes, these chronic wounds can be more taxing than the underlying disease itself. Although many newer methods are available to handle such situations, the role of stem cells in the management of such wounds is an exciting area that needs to be explored further. A review of literature has been done regarding the role of stem cells in the management of chronic wounds. The abnormal pathology in such wounds is discussed and the possible role of stem cells for optimal healing in such cases would be detailed.

Prognosis of full-thickness skin defects in premature infants

BACKGROUND

In the extremities of premature infants, the skin and subcutaneous tissue are very pliable due to immaturity and have a greater degree of skin laxity and mobility. Thus, we can expect wounds to heal rapidly by wound contraction. This study investigates wound healing of full-thickness defects in premature infant extremities.

METHODS

The study consisted of 13 premature infants who had a total of 14 cases of full-thickness skin defects of the extremities due to extravasation after total parenteral nutrition. The wound was managed with intensive moist dressings with antibiotic and anti-inflammatory agents. After wound closure, moisturization and mild compression were performed.

RESULTS

Most of the full-thickness defects in the premature infants were closed by wound contraction without granulation tissue formation on the wound bed. The defects resulted in 3 pinpoint scars, 9 linear scars, and 2 round hypertrophic scars. The wounds with less granulation tissue were healed by contraction and resulted in linear scars parallel to the relaxed skin tension line. The wounds with more granulation tissue resulted in round scars. There was mild contracture without functional abnormality in 3 cases with a defect over two thirds of the longitudinal length of the dorsum of the hand or foot. The patients' parents were satisfied with the outcomes in 12 of 14 cases.

CONCLUSIONS

Full-thickness skin defects in premature infants typically heal by wound contraction with minimal granulation tissue and scar formation probably due to excellent skin mobility.

Nonviral human beta defensin-3 expression in a bioengineered human skin tissue: a therapeutic alternative for infected wounds

The innate immune system differentially regulates the expression of host defense peptides to combat infection during wound healing. We enhanced the expression of a host defense peptide, human beta defensin-3 (hBD-3), in keratinocytes to generate a three-dimensional biologic dressing to improve healing of infected wounds. The NIKS human keratinocyte cell line was stably transfected ex vivo with a construct containing an epidermis-specific promoter driving hBD-3 (NIKS(hBD) (-3) ) using nonviral methods. Levels of hBD-3 mRNA and protein in three-dimensional skin tissue produced from NIKS(hBD) (-3) were determined using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Tissue architecture was characterized by hematoxylin and eosin staining and by indirect immunofluorescence using proliferation and keratinocyte differentiation markers. Antimicrobial activity was assessed using an in vitro bacterial growth assay and in vivo using a murine burn infection model. Three-dimensional full thickness skin tissues containing epidermal NIKS(hBD) (-3) or control NIKS possessed histologic features of interfollicular epidermis and exhibited normal tissue growth and differentiation. NIKS(hBD) (-3) tissue contained approximately fivefold more hBD-3 protein than tissue containing unmodified control NIKS. In vitro studies showed that NIKS(hBD) (-3) tissue produced a significant reduction in the growth of Staphylococcus aureus multiple peptide resistance factor (mprF) compared with control tissue. In an in vivo infected murine burn model, NIKS(hBD) (-3) tissue resulted in a 90% reduction in bacterial growth. These results demonstrate that sustained delivery of hBD-3 by a bioengineered skin tissue results in a therapeutically relevant reduction in growth of a S. aureus strain in an animal model of infected third-degree burn wounds.

Formation of hypertrophic scars: evolution and susceptibility

Formation of hypertrophic scars is a common complication of wound healing, and at present little is known about the incidence and risk factors. Our aim was to analyse the incidence, progression, and regression of postoperative hypertrophic scars over time and to identify risk factors of hypertrophic scars. Patients who had had bilateral reduction mammoplasty or median sternotomy incision were included in the study. All patients were examined at 3 and 12 months postoperatively. We recorded: height, weight, allergy status, smoking status, skin type, tanning, and shape of the scar 3 and 12 months postoperatively. Of the 204 patients who were included, 122 (60%) developed a hypertrophic scar within 12 months of operation. Of these patients, 117 (96%) developed a hypertrophic scar within 3 months of operation. Twelve months postoperatively, 66/204 patients (32%) had a hypertrophic scar. In 31 of the 66 of the patients with a hypertrophic scar 3 months postoperatively (47%), the hypertrophic scar(s) regressed after 3 and 12 months. Smoking and age were associated with formation of hypertrophic scars. In conclusion, 60% of patients developed hypertrophic scars postoperatively, typically during the first three months. Most hypertrophic scars that are present after three months are still hypertrophic after 12 months. Young, non-smoking patients are more susceptible to formation of hypertrophic scars.

The role of hyaluronan in wound healing

The polysaccharide hyaluronan (HA) (synonyms - hyaluronic acid, hyaluronate) is a versatile, polymorphic, glycosoaminoglycan with vast biological functions. HA is found throughout the body, primarily residing in skin, thus playing an important role in wound healing. Research regarding HA's function has changed over the years, primarily focussing on a particular aspect or function. The contribution of HA in each stage of normal wound healing as well as its clinical wound dressing applications will be examined.

Microbial barriers

Barrier wound therapy is commonplace in the health care environment and functions to limit bacterial colonization and infection in both acute wounds and recalcitrant chronic wounds. This article reviews the nature of acute and chronic wounds and their available adjunctive barrier therapies.

Electromagnetic fields as first messenger in biological signaling: Application to calmodulin-dependent signaling in tissue repair

BACKGROUND

The transduction mechanism for non-thermal electromagnetic field (EMF) bioeffects has not been fully elucidated. This study proposes that an EMF can act as a first messenger in the calmodulin-dependent signaling pathways that orchestrate the release of cytokines and growth factors in normal cellular responses to physical and/or chemical insults.

METHODS

Given knowledge of Ca(2+) binding kinetics to calmodulin (CaM), an EMF signal having pulse duration or carrier period shorter than bound Ca(2+) lifetime may be configured to accelerate binding, and be detectable above thermal noise. New EMF signals were configured to modulate calmodulin-dependent signaling and assessed for efficacy in cellular studies.

RESULTS

Configured EMF signals modulated CaM-dependent enzyme kinetics, produced several-fold increases in key second messengers to include nitric oxide and cyclic guanosine monophosphate in chondrocyte and endothelial cultures and cyclic adenosine monophosphate in neuronal cultures. Calmodulin antagonists and downstream blockers annihilated these effects, providing strong support for the proposed mechanism.

CONCLUSIONS

Knowledge of the kinetics of Ca(2+) binding to CaM, or for any ion binding specific to any signaling cascade, allows the use of an electrochemical model by which the ability of any EMF signal to modulate CaM-dependent signaling can be assessed a priori or a posteriori. Results are consistent with the proposed mechanism, and strongly support the Ca/CaM/NO pathway as a primary EMF transduction pathway.

GENERAL SIGNIFICANCE

The predictions of the proposed model open a host of significant possibilities for configuration of non-thermal EMF signals for clinical and wellness applications that can reach far beyond fracture repair and wound healing.

Hypoxia regulates the expression of extracellular matrix associated proteins in equine dermal fibroblasts via HIF1

BACKGROUND

Exuberant granulation tissue (EGT), a fibrotic healing disorder resembling the human keloid, occurs almost exclusively in limb wounds of horses and may be caused in part by a relative state of hypoxia within the wound.

OBJECTIVE

The objectives of this study were therefore to (1) assess the effects of hypoxia on equine dermal fibroblast (EDF) proliferation and apoptosis, (2) study the effects of hypoxia on the expression of key extracellular matrix (ECM) associated proteins and determine if such effects are dependent on hypoxia-inducible factor (HIF), and (3) determine if EDFs from the body or limb respond differently to hypoxia.

METHODS

EDFs were isolated and cultured from skin from body or limb under normoxic or hypoxic conditions for up to 7days.

RESULTS

Hypoxia significantly stimulated EDF proliferation, but had no effect on cell survival. The hypoxia-mimetic agent CoCl(2) up-regulated COL1A1 expression and down-regulated MMP2 expression, suggesting an increase in ECM synthesis and a decrease in turnover. Both regulatory effects were inhibited by the addition of echinomycin, indicating that they are mediated by the transcriptional regulatory activity of HIF. No differences were observed between EDFs originating from body or limb for any effect of hypoxia or CoCl(2), suggesting that EGT development does not depend on intrinsic properties of limb fibroblasts.

CONCLUSIONS

We conclude that hypoxia regulates ECM remodeling via HIF1 in EDFs, and that this may be an important determinant in the pathogenesis of equine EGT.

Moderate intensity physical training accelerates healing of full-thickness wounds in mice

Physical training influences the cells and mediators involved in skin wound healing. The objective of this study was to determine the changes induced by different intensities of physical training in mouse skin wound healing. Ninety male C57BL6 mice (8 weeks old, 20-25 g) were randomized into three physical training groups: moderate (70% VO2max), high (80% VO2max), and strenuous intensity (90% VO2max). Animals trained on a motorized treadmill for 8 weeks (E lesion: physical training until the day of excisional lesion, N = 10) or 10 weeks (E euthan: physical training for 2 additional weeks after excisional lesion until euthanasia, N = 10), five times/week, for 45 min. Control groups (CG) trained on the treadmill three times/week only for 5 min (N = 10). In the 8th week, mice were anesthetized, submitted to a dorsal full-thickness excisional wound of 1 cm², and sacrificed 14 days after wounding. Wound areas were measured 4, 7, and 14 days after wounding to evaluate contraction (d4, d7 and d14) and re-epithelialization (d14). Fragments of lesion and adjacent skin were processed and submitted to routine histological staining. Immunohistochemistry against alpha-smooth muscle actin (α-SMA) was performed. Moderate-intensity training (M) until lesion (M/E lesion) led to better wound closure 7 days after wounding compared to controls and M/E euthan (P < 0.05), and both moderate-intensity groups showed better re-epithelialization rates than controls (M/E lesion = 85.9%, M/E euthan = 96.4% and M/CG = 79.9%; P < 0.05). Sections of M/E lesion and M/E euthan groups stained with hematoxylin-eosin, Picrosirius red and α-SMA showed the most mature granulation tissues among all trained groups and controls. Thus, moderate-intensity physical training improves skin wound healing.

Histological evolution of chronic wounds under negative pressure therapy

BACKGROUND

Negative pressure wound therapy (NPT) has achieved widespread success in the treatment of difficult wounds. However, its effects are but partially explored, and investigations mostly concentrated at the wound-dressing interface; a detailed histological description of the evolution of wounds under NPT is still lacking.

MATERIALS AND METHODS

Subsequent punch biopsies of NPT-treated chronic wounds of human patients were analysed. Phenomena occurring in wounds were quantified by analysis of proliferating cells nuclear antigen (PCNA) (proliferating nuclei), CD31 (blood vessels), CD68p (macrophages) and CD45 (lymphocytes) stained slides.

RESULTS

Three layers were identified in day-0 wounds. Over time, under NPT, the layers behaved differently: the most superficial (1.5 mm) developed granulation tissue, constant in thickness, with high proliferation index, increased in blood vessels density and developed acute inflammation. Instead, the two deeper layers decreased in proliferation rate, maintained vessels density unchanged, were cleared of chronic inflammation and oedema and underwent progression towards stable tissue.

DISCUSSION

Indeed, while most research has focused on induction of superficial granulation tissue by NPT, deeper layers appear to be also affected, with relieving of chronic inflammation and tissue stabilisation. This may be an important and under-appreciated effect, playing a role in the known positive outcomes of NPT, such as better graft-taking rates.

Tissue repair: The hidden drama

As living beings who encounter every kind of traumatic event from paper cut to myocardial infarction, we must possess ways to heal damaged tissues. While some animals are able to regrow complete body parts following injury (such as the earthworm who grows a new head following bisection), humans are sadly incapable of such feats. Our means of recovery following tissue damage consists largely of repair rather than pure regeneration. Thousands of times in our lives, a meticulously scripted but unseen wound healing drama plays, with cells serving as actors, extracellular matrix as the setting, and growth factors as the means of communication. This article briefly reviews the cells involved in tissue repair, their signaling and proliferation mechanisms, and the function of the extracellular matrix, then presents the actors and script for the three acts of the tissue repair drama.

Evaluation of a novel high-intensity focused ultrasound device: preclinical studies in a porcine model

BACKGROUND

High-intensity focused ultrasound (HIFU) has been applied clinically for the noninvasive treatment of pathological conditions in various organs for over 50 years; however, there are little data describing the use of thermal HIFU to ablate fat for body contouring and treatment of collagen-rich layers. A novel device under clinical investigation (LipoSonix; Medicis Technologies Corporation, Bothell, Washington) uses HIFU to eliminate unwanted adipose tissue.

OBJECTIVES

The authors describe the results of HIFU treatment in a series of preclinical studies performed in a validated porcine model.

METHODS

Preclinical research included in vivo treatment of the abdominal subcutaneous adipose tissue of swine with transcutaneous HIFU therapy. Endpoint analyses included thermocouple temperature data, full-body necropsy, local pathology and histology studies, clinical hematology, urinalysis, and blood chemistry parameters, including lipid panels.

RESULTS

The application of HIFU energy levels of 166 to 372 J/cm(2) generated tissue temperature approaching 70°C, which was restricted to the focal area (n = seven). Application of 68 and 86 J/cm(2) did not produce clinically-significant changes in serum liver function tests, free fatty acids, or cholesterol (n = eight). Gross examination of tissue from various organs showed no evidence of fat emboli or accumulation (n = two). Histology demonstrated well-preserved vasculature and intact nerve fibers within the HIFU focal area (n = three). Following treatment with 85.3 to 270 J/cm(2), normal healing response included the migration of macrophages into the damaged tissue and removal of disrupted cellular debris and lipids (n = 8).

CONCLUSIONS

In a preclinical swine model, the controlled thermal effect of HIFU appears to provide a safe and effective means for ablating subcutaneous adipose tissue.

Urethral rest: role and rationale in preparation for anterior urethroplasty

OBJECTIVES

To report the outcomes of men treated initially with a period of urethral rest to allow tissue recovery before anterior urethroplasty. Many men referred to referral centers for anterior urethral reconstruction often present soon after the endoscopic manipulation of severe strictures.

METHODS

We reviewed our database of all anterior urethroplasties performed by a single surgeon from 2007 to 2009. Urethral rest was accomplished by removal of the indwelling catheter, cessation of self-catheterization, and/or suprapubic urinary diversion before urethral reconstruction.

RESULTS

During the study period, 210 patients underwent urethral reconstruction at our center. Men who had undergone meatoplasty or posterior urethroplasty were excluded, leaving 128 anterior urethroplasty patients available for analysis. Of these men, 28 (21%) were preoperatively given an initial period of urethral rest (median duration 3 months) because of recent urologic manipulation occurring immediately before referral. Of the 28 patients, 15 (54%) received suprapubic catheters. Urethral rest promoted identification of severely fibrotic stricture segments, enabling focal or complete excision in 75% (excision and primary anastomosis in 12 [43%] and augmented anastomosis in 9 [32%]), a percentage similar to that for those undergoing reconstruction without preliminary manipulation mandating urethral rest (82%). Stricture recurrence developed in 4 (14%) of the 28 rest patients, a rate again similar to that for the remainder of the urethroplasty population (10%).

CONCLUSIONS

The results of our study have shown that recently manipulated anterior urethral strictures often declare themselves to be obliterative within several months of urethral rest, thus enabling successful urethroplasty by focal or complete excision.

The evidence for the role of transforming growth factor-beta in the formation of abnormal scarring

The complex biological and physiological mechanisms that result in poor quality scarring are still not fully understood. This review looks at current evidence of the role of transforming growth factor-beta (TGFβ) in this pathological process.

Modulating endogenous electric currents in human corneal wounds--a novel approach of bioelectric stimulation without electrodes

PURPOSE

To measure electric current in human corneal wounds and test the feasibility of pharmacologically enhancing the current to promote corneal wound healing.

METHODS

Using a noninvasive vibrating probe, corneal electric current was measured before and after wounding of the epithelium of donated postmortem human corneas. The effects of drug aminophylline and chloride-free solution on wound current were also tested.

RESULTS

Unwounded cornea had small outward currents (0.07 μA/cm²). Wounding increased the current more than 5 fold (0.41 μA/cm²). Monitoring the wound current over time showed that it seemed to be actively regulated and maintained above normal unwounded levels for at least 6 hours. The time course was similar to that previously measured in rat cornea. Drug treatment or chloride-free solution more than doubled the size of wound currents.

CONCLUSIONS

Electric current at human corneal wounds can be significantly increased with aminophylline or chloride-free solution. Because corneal wound current directly correlates with wound healing rate, our results suggest a role for chloride-free and/or aminophylline eyedrops to enhance healing of damaged cornea in patients with reduced wound healing such as the elderly or diabetic patient. This novel approach offers bioelectric stimulation without electrodes and can be readily tested in patients.

Management of chyle leak post neck dissection: a case report and literature review

Chyle leakage post head-and-neck resection is a rare but potentially life-threatening complication. Management may be problematic and prolonged. Recently, thoracoscopic ligation of the thoracic duct has emerged as a promising technique to definitively treat this difficult problem. We present a recent case of a hemimandibulectomy, radical modified neck dissection and osseocutaneous fibular-free-flap complicated by a chyle leakage. The chyle leak was successfully treated with thoracoscopic ligation of the thoracic duct. In the light of our clinical experience and following a thorough literature review, we have proposed that complicated or high-output chyle leaks (>1000 ml day(-1)) should be treated with early thoracoscopic thoracic duct ligation.

Current concepts for the use of platelet-rich plasma in the foot and ankle

Platelet-rich plasma (PRP) injections have been used and studied since the 1970s. Its use has become more popularized over the last several years in the treatment of foot and ankle injuries. Platelets are a normal product found in the clotting cascade and inflammatory process of healing. They produce granules that release growth factors that promote healing. PRP works by increasing the concentration of platelets, thereby increasing the concentration of growth factors and increasing healing potential. PRP has an advantage over many tissue engineering products in that it is autologous. It has been studied and used for the treatment of tendon injuries, chronic wounds, ligamentous injuries, cartilage injuries, muscle injuries, and bone augmentation. The results from in vitro and in vivo studies in foot and ankle injuries are promising. The applications for treatment in the foot and ankle may be broader than once thought.

Biofilms: do they affect wound healing?

Biofilms are known to exist in wounds, and it is suspected that their presence may delay wound healing, especially in chronic wounds; however, the evidence to support or refute this is not yet conclusive. This literature review has found that there is some evidence, both in vitro and in vivo, that the extracellular polysaccharide (EPS) matrix protects the biofilm from some inflammatory processes key to wound healing. The mechanisms of these effects and how this translates into clinical practice are still unknown. Strategies to manage biofilms within wounds are being investigated and may include use of silver, surgical debridedment, antibiotics and quorum-sensing inhibitors but no firm conclusions can yet be drawn from these studies. In conclusion, while there is a growing body of evidence to suggest that biofilms do indeed influence aspects of wound healing, there is still a large gap in our understanding of how this affects the wounds of clinical patients or how to improve rates of healing.

MicroRNAs in skin and wound healing

MicroRNAs (miRNAs) are small endogenous RNA molecules ∼22 nt in length. miRNAs are capable of posttranscriptional gene regulation by binding to their target messenger RNAs (mRNAs), leading to mRNA degradation or suppression of translation. miRNAs have recently been shown to play pivotal roles in skin development and are linked to various skin pathologies, cancer, and wound healing. This review focuses on the role of miRNAs in cutaneous biology, the various methods of miRNA modulation, and the therapeutic opportunities in treatment of skin diseases and wound healing.

Reconstruction in Warfare Injuries

Traumatic injuries, especially in the combat setting, stress the surgical team that may be sited in a remote forward area, battling against paucity of time, resources and infrastructure. The lone surgeon may be faced with the arduous challenge of saving life. There is seldom thought given to reconstruction in this high-pressure situation. If the patient survives, morbidity for want of reconstruction can be severe and quality of life can suffer significantly. Reconstruction after 3 to 5 days is fraught with complications and usually does compromise outcome in the post-operative phase. The reconstructive surgeon should be involved early in the management as he can provide coverage for large soft tissue defects after aggressive debridement with panache. If the patient is haemodynamically stable, he should be transferred urgently, preferrably by air, to a higher centre with multi-specialty care, especially being equipped with an orthopaedic and trauma reconstructive surgeon. It has been proved beyond doubt that the healing improves significantly and there is marked decrease in morbidity if coverage of wounds is provided early, before colonized wounds get infected.

The role of thrombin-activatable fibrinolysis inhibitor in diabetic wound healing

INTRODUCTION

One of the major complications in patients with diabetes mellitus is impaired wound healing. The fibrinolytic system is involved in parts of the wound healing process and deficiency of thrombin-activatable fibrinolysis inhibitor (TAFI) results in delayed wound closure. Moreover, levels of TAFI are affected by diabetes mellitus. The aim of this study was to elucidate the effect of hyperglycaemia on TAFI and to determine the effect of deficiency of TAFI on wound healing under hyperglycaemic conditions.

MATERIALS AND METHODS

Hyperglycaemia was induced with streptozotocin (STZ) and used as a model for diabetes mellitus. TAFI plasma levels and TAFI gene expression in the liver were determined. Incisional and excisional wound healing were studied in non-treated and STZ-treated wild-type and TAFI-deficient mice. Wound closure was scored daily as open or closed.

RESULTS

Mice treated with STZ showed hyperglycaemia, and TAFI plasma levels and TAFI gene expression were increased in diabetic mice. TAFI-deficient mice and diabetic wild-type and diabetic TAFI-deficient mice showed delayed wound healing of incisional wounds. No differences were observed between diabetic and non-diabetic TAFI-deficient mice and between diabetic wild-type and diabetic TAFI-deficient mice.

CONCLUSIONS

This study illustrated that TAFI was affected by hyperglycaemia and confirmed that TAFI is involved in wound healing. No additional effect was observed under hyperglycaemic conditions, indicating that deficiency of TAFI did not have an additive or synergistic effect in diabetic wound healing. Further research has to elucidate if TAFI and hyperglycemia affect wound healing via similar mechanisms.

m-Calpain activation is regulated by its membrane localization and by its binding to phosphatidylinositol 4,5-bisphosphate

m-Calpain plays a critical role in cell migration enabling rear de-adhesion of adherent cells by cleaving structural components of the adhesion plaques. Growth factors and chemokines regulate keratinocyte, fibroblast, and endothelial cell migration by modulating m-calpain activity. Growth factor receptors activate m-calpain secondary to phosphorylation on serine 50 by ERK. Concurrently, activated m-calpain is localized to its inner membrane milieu by binding to phosphatidylinositol 4,5-bisphosphate (PIP(2)). Opposing this, CXCR3 ligands inhibit cell migration by blocking m-calpain activity secondary to a PKA-mediated phosphorylation in the C2-like domain. The failure of m-calpain activation in the absence of PIP(2) points to a key regulatory role, although whether this PIP(2)-mediated membrane localization is regulatory for m-calpain activity or merely serves as a docking site for ERK phosphorylation is uncertain. Herein, we report the effects of two CXCR3 ligands, CXCL11/IP-9/I-TAC and CXCL10/IP-10, on the EGF- and VEGF-induced redistribution of m-calpain in human fibroblasts and endothelial cells. The two chemokines block the tail retraction and, thus, the migration within minutes, preventing and reverting growth factor-induced relocalization of m-calpain to the plasma membrane of the cells. PKA phosphorylation of m-calpain blocks the binding of the protease to PIP(2). Unexpectedly, we found that this was due to membrane anchorage itself and not merely serine 50 phosphorylation, as the farnesylation-induced anchorage of m-calpain triggers a strong activation of this protease, leading notably to an increased cell death. Moreover, the ERK and PKA phosphorylations have no effect on this membrane-anchored m-calpain. However, the presence of PIP(2) is still required for the activation of the anchored m-calpain. In conclusion, we describe a novel mechanism of m-calpain activation by interaction with the plasma membrane and PIP(2) specifically, this phosphoinositide acting as a cofactor for the enzyme. The phosphorylation of m-calpain by ERK and PKA by growth factors and chemokines, respectively, act in cells to regulate the enzyme only indirectly by controlling its redistribution.

Is obesity protective against wound healing complications in pilon surgery? Soft tissue envelope and pilon fractures in the obese

Open treatment of pilon fractures is associated with wound healing complications. A traumatized, limited soft tissue envelope contributes to wound healing complications. Obese patients have larger soft tissue envelopes around the ankle, theoretically providing a greater area for energy distribution and more accommodation to implants. This led us to test 2 hypotheses: (1) ankle dimensions in obese patients are larger than in lean patients, and (2) the increased soft tissue envelope volume translates into fewer wound complications. A consecutive series of 176 pilon fractures treated from March 2002 to December 2007 were retrospectively reviewed. Inclusion criteria were adults who received a preoperative computed tomography (CT) scan and were treated with a staged protocol including plating. Patients with body mass index (BMI) >30 were compared to those with BMI <30 for CT-derived ankle dimensions and wound complications. Comorbidities were evaluated for their role as potential confounders. Thirty-one fractures in obese patients were compared to 83 in lean patients. The average ratio of bone area to soft tissue area at the tibial plafond was 0.35 for the obese group and 0.38 for the lean group (P=.012). There were 8 major wound-healing complications. Four occurred in the obese group (incidence 13%), and 4 in the lean group (incidence 5%) (P=.252). Ankle dimensions in clinically obese patients are larger than in lean patients. Obesity does not appear to be protective of wound-healing complications, but rather there is a trend toward the opposite.

Effects of pulsed electromagnetic fields on interleukin-1 beta and postoperative pain: a double-blind, placebo-controlled, pilot study in breast reduction patients

BACKGROUND

Surgeons seek new methods of pain control to reduce side effects and speed postoperative recovery. Pulsed electromagnetic fields are effective for bone and wound repair and pain and edema reduction. This study examined whether the effect of pulsed electromagnetic fields on postoperative pain was associated with differences in levels of cytokines and angiogenic factors in the wound bed.

METHODS

In this double-blind, placebo-controlled, randomized study, 24 patients, undergoing breast reduction for symptomatic macromastia received pulsed electromagnetic field therapy configured to modulate the calmodulin-dependent nitric oxide signaling pathway. Pain levels were measured by a visual analogue scale, and narcotic use was recorded. Wound exudates were analyzed for interleukin (IL)-1 beta, tumor necrosis factor-alpha, vascular endothelial growth factor, and fibroblast growth factor-2.

RESULTS

Pulsed electromagnetic fields produced a 57 percent decrease in mean pain scores at 1 hour (p < 0.01) and a 300 percent decrease at 5 hours (p < 0.001), persisting to 48 hours postoperatively in the active versus the control group, along with a concomitant 2.2-fold reduction in narcotic use in active patients (p = 0.002). Mean IL-1 beta concentration in the wound exudates of treated patients was 275 percent lower (p < 0.001). There were no significant differences found for tumor necrosis factor-alpha, vascular endothelial growth factor, or fibroblast growth factor-2 concentrations.

CONCLUSIONS

Pulsed electromagnetic field therapy significantly reduced postoperative pain and narcotic use in the immediate postoperative period. The reduction of IL-1 beta in the wound exudate supports a mechanism that may involve manipulation of the dynamics of endogenous IL-1 beta in the wound bed by means of a pulsed electromagnetic field effect on nitric oxide signaling, which could impact the speed and quality of wound repair.

Skin collagen synthesis is depressed in patients with severe sepsis

BACKGROUND

Skin is an essential barrier in maintaining a stable internal environment. Adequate regenerative capacity is crucial to overcome the homeostatic challenges caused by a septic insult. In sepsis, coagulation and inflammation are activated to restore homeostasis, but it is not known whether sepsis also alters tissue regeneration processes such as skin collagen synthesis.

METHODS

In this prospective observational study, we measured aminoterminal propeptides of collagens I and III (PINP, PIIINP) from blister fluid of sepsis patients. Blister fluid was obtained from experimental blisters induced on intact abdominal skin 4 times: within the first 48 hours from the first organ failure, on the fifth day, and at 3 and 6 months thereafter. Forty-four patients with severe sepsis were enrolled. The median age was 63 years (25th-75th percentile, 53-71 years). The median Acute Physiology and Chronic Health Evaluation II score on admission was 26 (22-30). Thirty-day mortality was 25%. Fifteen healthy adults were used as controls.

RESULTS

Median PIIINP and PINP levels in septic patients were lower in comparison with controls in the first blister (40.8 microg/L [25th-75th percentile, 22.2-77.1 microg/L], P = 0.028 and 69.9 microg/L [32.4-112.7 microg/L], P < 0.001, respectively) and in the blister induced on day 5 (38.8 microg/L [19.9-68.5 microg/L], P < 0.001 and 90.0 [35.1-138.8 microg/L], P < 0.001, respectively). The survivors revealed an overexpression at 3 months, whereas normal values of PIIINP and PINP were reestablished at 6 months.

CONCLUSIONS

Skin collagen synthesis is depressed during severe sepsis and is followed by a compensatory response 3 and 6 months after the onset of sepsis.