The biomechanical effects of deep tissue support as related to brow and facelift procedures

The adverse effects of increased tension across a healing wound are well known. However, the effect of closing a wound in layers in order to decrease tension on the epidermis has been a source of controversy. It is hypothesized that deep tissue support decreases skin tension upon wound closure. In order to clarify this issue, a two-part study was designed to address the immediate effects of deep tissue support in vitro using fresh-frozen cadavers and in vivo on patients undergoing scheduled surgery. Closing skin tension was measured at standard reference points in coronal brow lift and rhytidectomy procedures performed with and without galeal closure and superficial musculoaponeurotic system (SMAS) procedures, respectively. Deep tissue support was found to significantly (p less than 0.05) decrease skin tension at the time of skin closure at standard reference points in coronal brow lift and rhytidectomy procedures performed on fresh-frozen cadavers. Similar significant (p less than 0.05) decreases in closing skin tension also were found in vivo in patients undergoing similar surgical procedures. Stress relaxation was not found to play a significant role in contributing to this immediate decrease in closing skin tension. It would appear, therefore, that deep tissue support, in the form of galeal closure and an SMAS procedure in coronal brow lift and rhytidectomy procedures, respectively, provides increased viscoelastic support, producing immediate significant decreases in closing skin tension in these procedures. The beneficial effects on wound healing, scar formation, tension-related trophic skin changes, and possible improved long-term results are discussed.     

Reduction of postischemic edema with hyperbaric oxygen

In recent years, reports have shown positive effects of hyperbaric oxygen (HBO) treatment in posttraumatic circulatory insufficiency of the extremities. A tourniquet model for temporary ischemia was used to examine such treatment in rats. The circulation of the rat hindlimb was interrupted for 3 hours, while the contralateral uninjured leg served as control. There was a significant (p less than 0.001) postischemic edema in the tourniquet leg up to 48 hours after restoration of circulation. One group of animals received treatment with hyperbaric oxygen at 2.5 atmospheres absolute (ATA) for 45 minutes after release of the tourniquet. This significantly reduced (p less than 0.001) the postischemic edema, and the reduction persisted for 40 hours after the last treatment. It is concluded that hyperbaric oxygen reduces postischemic edema. Hyperbaric oxygen may therefore be useful as an adjuvant in the treatment of acute ischemic conditions when surgical repair alone fails or is not sufficient to reverse the ischemic process.     

The inhibition of skeletal changes in a rat burn model with a local muscle flap

The effects of early wound closure using a local muscle flap on the development of periosteal new bone formation in a rat burn model were studied. Following a full-thickness burn to one hind limb, periosteal new bone formation along the tibial diaphysis was measured by the use of the fluorochrome agent calcein and an image-analysis system. Prostaglandin E levels, a known inflammatory mediator, from the bone beneath the burn also were measured. Periosteal new bone formation was inhibited by 50 percent in animals that had debridement and wound closure with a gastrocnemius muscle flap and skin graft on postburn day 2 compared to untreated controls or animals closed with skin grafts only. There was a trend toward reduced prostaglandin E measurements from tibial sections in the early closure group compared to untreated controls. This study demonstrates that early wound closure using a local muscle flap inhibits the periosteal new bone formation which is possibly associated with the inflammation in a rat burn model.     

Effects of tourniquet-induced ischemia on the release of proopiomelanocortin derivatives determined in peripheral blood plasma.

Proopiomelanocortin (POMC) is expressed in pituitary, central nervous system, and in a few peripheral tissues. This study addresses the hypothesis that metabolic stressors, such as acidosis, may induce the release of POMC derivatives into the cardiovascular system not only from the pituitary but also from other sites of POMC expression. In our study, we investigated the liberation of POMC derivatives from peripheral tissues under a state of acidosis achieved by tourniquet-induced ischemia, alteration of lactate concentration, and base excess. In eight patients undergoing knee arthroplasty under spinal anesthesia, catheters were inserted into the femoral vein proximally to thigh tourniquet location. Blood was drawn from these catheters 5 min before and 40 s, 5 min, and 10 min after tourniquet deflation to measure plasma concentrations of N-acetyl-beta-endorphin immunoreactive material (IRM), beta-endorphin IRM, authentic beta-endorphin, adrenocorticotropin, lactate, pH, and base excess. In five of eight patients, we found a significant increase of beta-endorphin IRM levels 40 s after tourniquet deflation compared with predeflation levels; 5 and 10 min after tourniquet deflation, the beta-endorphin IRM levels were below the detection limit. Thus beta-endorphin IRM was released from ischemic limb tissues into the cardiovascular system. Only a small part of the determined beta-endorphin IRM corresponded to authentic beta-endorphin. Forty seconds after tourniquet deflation, the beta-endorphin IRM concentration correlated with base excess (r < 0.71; P < 0.05); no significant correlations were found with pH or lactate levels. Thus it was shown here for the first time that ischemic stress may induce the release of beta-endorphin IRM from nonpituitary tissues.     

Effects of bio-active ceramic resources in cutaneous wound healing and the role of TGF-β signaling

The wound healing process is a highly orchestrated process, which includes inflammation, re-epithelialization, granulation tissue formation, matrix formation and re-modeling. In this paper, we attempt to determine if bio-active ceramic resource powder particles had an effect on cutaneous wound healing. Furthermore, we investigated its related mechanism and the expression of Smads of cutaneous wound healing, which can be accelerated by bio-active ceramic ointment. Topically applied lesions of 5%, 10% and 15% bio-active ceramic ointment (AO) showed accelerated wound closure, re-epithelialization, and the related immediate down stream of TGF-β (p-Smad2/3 and Smad3) was suppressed. In particular, 10% and 15% AO lesions became closed faster at Days 3 and 4 of post-wound and p-Smad2/3 was also suppressed. All AO lesions showed accelerated mild wound closure at Day 6, but there were no significant difference. Several papers reported that Smad3 may mediate the signaling pathways that is inhibitory to wound healing, as the deletion of Smad3 leads to enhanced re-epithelialization and contraction of the wound area. This study showed that topical, bio-active ceramic ointment applications accelerated wound closure, re-epithelialization and the suppression of Smad proteins (p-Smad2/3, Smad3). The data revealed that the suppression of Smad3, which was induced by bio-active ceramic resources powder particles affected re-epithelialization and cutaneous wound closure. At the end of this paper, we concluded that bio-active ceramic resources affect cutaneous wound healing by accelerating the re-epithelialization of keratinocytes and that is mediated by the suppression of related protein, Smad3.     

Matrix metalloproteinases (MMPs) are required for wound closure and healing during larval leg regeneration in the flour beetle,Tribolium castaneum

Regenerative abilities are found ubiquitously among many metazoan taxa. To compare mechanisms underlying the initial stages of limb regeneration between insects and vertebrates, the roles of matrix metalloproteinases (MMPs) and fibroblast growth factor (FGF) signaling were investigated in the red flour beetle, Tribolium castaneum. RNA interference-mediated knockdown of MMP2 expression delayed wound healing and subsequent leg regeneration. Additionally, pairwise knockdown of MMP1/2 and MMP2/3, but not MMP1/3, resulted in inhibition of wound closure. Wound healing on the dorsal epidermis after injury was also delayed when MMPs were silenced. Our findings show that functionally redundant MMPs play key roles during limb regeneration and wound healing in Tribolium. This MMP-mediated wound healing is necessary for the subsequent formation of a blastema. In contrast, silencing of FGF receptor did not interfere with the initial stages of leg regeneration despite the alterations in tanning of the cuticle. Thus, insects and vertebrates appear to employ similar developmental processes for the initial stages of wound closure during limb regeneration, while the role of FGF in limb regeneration appears to be unique to vertebrates.     

Smart hydrogels based on semi-interpenetrating polymeric networks of collagen-polyurethane-alginate for soft/hard tissue healing,drug delivery devices,and anticancer therapies

In this work, hydrogels based on semi-interpenetrating polymeric networks (semi-IPN) based on collagen-polyurethane-alginate were studied physicochemically and from different approaches for biomedical application. It was determined that the matrices in the hydrogel state are crosslinked by the formation of urea and amide bonds between the biopolymer chains and the polyurethane crosslinker. The increment in alginate content (0–40 wt%) significantly increases the swelling capacity, generating semi-crystalline granular structures with improved storage modulus and resistance to thermal, hydrolytic, and proteolytic degradation. The in vitro bioactivity results indicated that the composition of these novel hydrogels stimulates the metabolic activity of monocytes and fibroblasts, benefiting their proliferation; while in cancer cell lines, it was determined that the composition of these biomaterials decreases the metabolic activity of breast cancer cells after 48 h of stimulation, and for colon cancer cells their metabolic activity decreases after 72 h of contact for the hydrogel with 40 wt% alginate. The matrices show a behavior of multidose release of ketorolac, and a higher concentration of analgesic is released in the semi-IPN matrix. The inhibition capacity of Escherichia coli is higher if the polysaccharide concentration is low (10 wt%). The in vitro wound closure test (scratch test) results indicate that the hydrogel with 20 wt% alginate shows an improvement in wound closure at 15 days of contact. Finally, the bioactivity of mineralization was evaluated to demonstrate that these hydrogels can induce the formation of carbonated apatite on their surface. The engineered hydrogels show biomedical multifunctionality and they could be applied in soft and hard tissue healing strategies, anticancer therapies, and drug release devices.     

Electron and light microscopy examination of capsules around breast implants.

An investigation, by scanning electron microscopy of the capsules formed around silicone breast implants revealed that they consist almost entirely of connective tissue. In contrast, the capsules around the Y-prostheses (with a polyurethane foam surface) showed a foreign body reaction. We believe that excessive capsule formation around silicone implants is, among other factors, most likely due to discrete or moderate bleeding with subsequent hematoma formation. Therefore, we favor a two-stage procedure for subcutaneous mastectomy with insertion of the implant at 4 to 6 months after the excision.     

Flap perfusion after free musculocutaneous tissue transfer: the impact of postoperative complications

In a previous study, the authors found persistence of pedicle blood flow up to 10 years after uncomplicated free latissimus dorsi transfer. In this study, the impact of postoperative complications (hematoma, thrombosis, infection) and successful surgical revision was tested. Since 1982, more than 1200 free tissue transfers have been performed at the authors' institution (Hannover Medical School). Of these, the authors selected two groups of 30 patients each who had received a free latissimus dorsi transfer to the lower leg without microsurgical nerve coaptation for wound coverage. All patients included in this study were carefully selected for clinical homogeneity, with one difference: group I comprised patients who had no postoperative complications after free latissimus dorsi transfer. Group II included only patients with major postoperative complications after the procedure. All flaps in group II survived after successful surgical revision. The arteries, which nourished the lower leg, were visualized and documented by means of a duplex scanner in both groups. Three different time intervals were chosen for measurements of blood flow: 4 to 6 months (groups I.I and II.I), 4 to 6 years (groups I.II and II.II), and 8 to 10 years (groups I.III and II.III). Quantitative measurements of local flap perfusion in milliliters per minute per 100 g tissue were performed by means of the hydrogen clearance technique. In each patient, a total of nine measurements was performed in three phases: phase A, before closing the vascular pedicle by manual compression (n = 3); phase B, with a closed pedicle (n = 3); and phase C, after releasing the vascular pedicle from manual compression (n = 3). Each measurement took approximately 10 minutes. One hundred percent closure of each pedicle in phase B was confirmed by the duplex scanner. Furthermore, all patients were monitored both clinically and by means of the hydrogen clearance technique during phase B for adequate blood supply to the lower leg. Lower leg perfusion showed no statistical differences for phases A, B, and C in all groups of patients. In group I, no statistical differences in local flap perfusion were encountered for phases A and C. In phase B, however, a statistically significant (p < 0.01) complete extinction of local flap perfusion was registered in all patients of group I at the site of the flap's skin paddle. In group II, however, persistent flap perfusion was registered during phase B in up to 50 percent of cases in one subgroup (II.III). No statistically significant alterations of local blood flow were registered in the surrounding tissue of group II during phases A, B, and C. Patients with thrombosis of the venous anastomosis (n = 7) seemed to have the highest incidence of loss of autonomous blood supply through the vascular pedicle (5 out of 11 cases). No inconstant results were found during the repetitive measurements (n = 3) for each patient in each phase. After uncomplicated free tissue transfer, the flap's intact vascular pedicle seems to play an important role in permanent flap survival up to 10 years after the procedure. Postoperative complications after free tissue transfer with successful surgical revision, especially venous thrombosis of the vascular anastomosis, may lead to loss of vascular flap autonomy over time.     

Wound healing ability of Xenopus laevis embryos. I. Rapid wound closure achieved by bisectional half embryos

We examined wound closure in 'half embryos' produced by the transverse bisection of Xenopus laevis embryos at the primary eye vesicle stage. Both the anterior- and posterior-half embryos survived for more than 6 days, and grew into 'half tadpoles'. Histology and videomicroscopy revealed that the open wound in the half embryo was rapidly closed by an epithelial sheet movement in the wound marginal zone. The time-course of wound closure showed a downward convex curve: the wound area decreased to one-fifth of the original area within 30 min, and the wound continued to contract slowly thereafter. The rapidity of closure of the epidermis as well as the absence of inflammatory cells are typical features of an embryonic type of wound healing. There was a dorso-ventral polarity in the motility of the epidermis: the wound was predominantly closed by the ventral and lateral epidermis. The change in the contour of the wound edge with time suggested a complex mechanism involved in the wound closure that could not be explained only by the purse-string theory. The present experimental system would be a unique and useful model for analyses of cellular movements in the embryonic epithelia.     

Closure of abdominal wounds by adhesive strips: a clinical trial.

In a randomized trial of wound closure in 512 abdominal wounds, wounds were closed with either reinforced Steristrip skin closures or interrupted silk sutures. Comparisons were made of wound pain and discomfort, wound infection, discharge, redness, width, and skin reaction. The causes of peeling of the tapes were assessed. The results showed that tapes were significantly more comfortable and that patients preferred them to sutures (P less than 0.01), but wide scars occurred more often. There was no difference in rates of wound infection and no case of allergy to the tapes was seen. Closure of abdominal wounds by these tapes is a satisfactory procedure that could be used more extensively.     

Impaired wound healing with defective expression of chemokines and recruitment of myeloid cells in TLR3-deficient mice

Skin injury evokes both innate and adaptive immune responses to restore tissue integrity. TLRs play a critical role in host responses to injurious insults. Previous studies demonstrated that RNAs released from damaged tissues served as endogenous ligands for TLR3. In this study, we investigated the involvement of TLR3 in skin restoration after injury. Full excisional wounds were created on the skin of mice with TLR3 deficiency. We found that skin wound closure in TLR3(-/-) mice was significantly delayed compared with control littermates. Wound healing parameters, including re-epithelialization, granulation formation, and neovascularization, were decreased in TLR3(-/-) mice. Further studies revealed that the absence of TLR3 led to defective recruitment of neutrophils and macrophages, in association with decreased expression of the chemokines, MIP-2/CXCL2, MIP-1α/CCL3, and MCP-1/CCL2, in the wound. Moreover, in wild type mice, the mRNA level and protein content of TLR3 was significantly upregulated in wounded skins and silencing of TLR3 signal adaptor Toll/IL-1R domain-containing adapter inducing IFN-β with small interfering RNA retarded wound closure. These results indicate an essential role for TLR3 and Toll/IL-1R domain-containing adapter inducing IFN-β in wound healing by regulating chemokine production and recruitment of myeloid cells to wound for tissue repair.     

The use of high pressure liquid chromatography (HPLC) for the separation of radiolabeled arachidonic acid and its metabolites produced by thrombin-treated human platelets. II. Establishment of optimal assay conditions.

We have utilized HPLC to develop optimal conditions for assaying the transformation of arachidonic acid in thrombin-treated human platelets. In the presence of increasing amounts of albumin, the total amount of radioactivity released from thrombin-treated platelets pre-labeled with 3H-arachidonic acid is first enhanced and then inhibited. Maximal release, reflecting primarily enhanced amounts of free labeled arachidonic acid, occurs at a final albumin concentration of 0.5 mg/ml. Calcium promoted the release of all radiolabeled metabolites, but it specifically enhanced HETE formation and release. Magnesium was without effect. Cyclo-oxygenase derived products constituted the bulk of released label at short time intervals, but after ten minutes exposure to thrombin in the presence of albumin (0.5 mg/ml) and 3 mM calcium, radioactivity in the released products was equally distributed among cyclo-oxygenase derived products (TXB2 + PGD2 + HHT), HETE and free arachidonic acid.     

Dual action of ATP hydrolysis couples lid closure to substrate release into the group II chaperonin chamber

Group II chaperonins are ATP-dependent ring-shaped complexes that bind nonnative polypeptides and facilitate protein folding in archaea and eukaryotes. A built-in lid encapsulates substrate proteins within the central chaperonin chamber. Here, we describe the fate of the substrate during the nucleotide cycle of group II chaperonins. The chaperonin substrate-binding sites are exposed, and the lid is open in both the ATP-free and ATP-bound prehydrolysis states. ATP hydrolysis has a dual function in the folding cycle, triggering both lid closure and substrate release into the central chamber. Notably, substrate release can occur in the absence of a lid, and lid closure can occur without substrate release. However, productive folding requires both events, so that the polypeptide is released into the confined space of the closed chamber where it folds. Our results show that ATP hydrolysis coordinates the structural and functional determinants that trigger productive folding.     

Cyclooxygenase and cytochrome P-450 pathways induced by fetal calf serum regulate wound closure in 3T6 fibroblast cultures through the effect of prostaglandin E2 and 12 and 20 hydroxyeicosatetraenoic acids

Wound-induced injury of 3T6 fibroblast cultures initiated a repair process stimulated by fetal calf serum (FCS) that restored the integrity of cell cultures. In these experimental conditions, FCS induced arachidonic acid (AA) release and eicosanoid production. Our results show that the inhibition of the cyclooxygenase (COX) and/or cytochrome P-450 pathways significantly decreases the wound closure, whereas that of the lipoxygenase pathway does not modify the wound repair process. Both EP(1) and EP(4) receptors of prostaglandin E(2) (PGE(2)) mediate PGE(2) stimulated 3T6 fibroblast wound closure. Our data suggest that calcium and cAMP are involved in the signaling event induced by PGE(2) during the 3T6 fibroblast wound repair process. On the other hand, we show that ketoconazole, a cytochrome P-450 inhibitor, hinders the wound closure induced by FCS in wounded 3T6 fibroblast cultures. 12 and 20 Hydroxyeicosatetraenoic acids (HETEs), which are key AA metabolites synthesized by cytochrome P-450, partially revert the effects of ketoconazole on the wound repair process. Thus, the COX and cytochrome P-450 pathways of the arachidonate cascade are involved in 3T6 fibroblast wound closure.     

Wound complications after median sternotomy: A study of 61 patients from a consecutive series of 9,279

Among a consecutive series of 9,279 sternotomies performed during a period of 2(1/2) years, 61 (0.66%) patients developed significant wound complications. Of these, 58 (95.1%) survived. Sternal infection occurred in 36 patients (0.39%). Predisposing factors included chronic obstructive pulmonary disease, diabetes mellitus, obesity, closed chest massage, prolonged assisted ventilation, and excessive bleeding after operation. Positive end expiratory pressure (PEEP) did not, in itself, predispose to sternal dehiscence. Intermittent positive pressure breathing (IPPB) treatments caused excessive coughing, which may have increased the likelihood of dehiscence. Disposable drapes and expeditious surgery probably contributed to the low incidence of wound infection. Early diagnosis, surgical debridement, rewiring and primary closure with substernal drainage, without continuous antibiotic irrigation, resulted in satisfactory resolution in most patients.     

Internal use of n-butyl 2-cyanoacrylate (Indermil) for wound closure: an experimental study.

n-Butyl 2-cyanoacrylate glue (Indermil) was used for the closure of dorsal wounds on rabbits. A 4-cm-long and 1-cm-wide laceration was created bilaterally on the back of 15 rabbits. One side was closed with absorbable 2-0 subcutaneous sutures and fast absorbable 3-0 skin sutures, whereas the other side was closed with cyanoacrylate glue applied on both deep and superficial tissues. A partial wound dehiscence occurred on the glue side in one animal at 2 weeks. The animal was killed at this time and considered a bad result in the glue group. In all other animals, no seroma, partial dehiscence, or wound infection occurred. Histopathologic analysis revealed that Indermil induced edema and a mild acute inflammatory reaction and resorbed almost completely within 2 months when applied to well-vascularized tissues. The application of glue on the cutaneous wound edges is a fast and easy procedure that does not seem to delay or inhibit the healing process or its quality.     

Wound healing ability of Xenopus laevis embryos. II. Morphological analysis of wound marginal epidermis

We previously showed that bisectional wounds made in Xenopus laevis embryos at the primary eye vesicle stage were rapidly closed. In this study, microscopic analyses, including scanning electron microscopy, on the morphology of the epidermis were conducted during wound closure in the half embryos. Bright fluorescence of Texas red-phalloidin showing actin filaments started to be visualized at the cut edge 10 min after wounding. It increased with time, forming a distinguished, though discontinuous, bundle along the wound margin. The wound closure was completely inhibited by 20 microm cytochalasin B, and almost completely by 50 mm 2,3-butanedione 2-monoxime, an inhibitor to myosin ATPase activity. Scanning electron microscopy revealed that the outer epidermal cells became extensively elongated in the radial direction, and the contour of the closing wound edge did not become smoother but remained ragged. Thus, a representative embryonic type of wound closure may be driven in Xenopus embryos by a complex mechanism, involving not only the actin 'purse-string' but also an inward movement of individual cells. Anyhow, the wound closure is a movement of the epidermal sheet maintaining cell-cell contact, and not involving locomotion of single cells separated from the wound edge.     

Proteins regulating cap-dependent translation are downregulated during total knee arthroplasty

Total knee arthroplasty (TKA) utilizes a tourniquet to reduce blood loss, maintain a clear surgical "bloodless" field, and to ensure proper bone-implant cementing. In 2007, over 600,000 TKAs were performed in the United States, and this number is projected to increase to 3.48 million procedures performed annually by 2030. The acute effects of tourniquet-induced ischemia-reperfusion (I/R) on human skeletal muscle cells are poorly understood and require critical investigation, as muscle atrophy following this surgery is rapid and represents the most significant clinical barrier to long-term normalization of physical function. To determine the acute effects of I/R on skeletal muscle cells, biopsies were obtained at baseline, maximal ischemia (prior to tourniquet release), and reperfusion (following tourniquet release). Quadriceps volume was determined before and 2 wk post-TKA by MRI. We measured a 36% decrease in phosphorylation of Akt Ser(473) during ischemia and 37% during reperfusion (P < 0.05). 4E-BP1 Thr(37/46) phosphorylation decreased 29% during ischemia and 22% during reperfusion (P < 0.05). eEF2 Thr(56) phosphorylation increased 25% during ischemia and 43% during reperfusion (P < 0.05). Quadriceps volume decreased 12% in the TKA leg (P < 0.05) and tended to decrease (6%) in the contralateral leg (P = 0.1). These data suggest cap-dependent translation initiation, and elongation may be inhibited during and after TKA surgery. We propose that cap-dependent translational events occurring during surgery may precipitate postoperative changes in muscle cells that contribute to the etiology of muscle atrophy following TKA.     

Modification of collagen by 3-deoxyglucosone alters wound healing through differential regulation of p38 MAP kinase

Background

Wound healing is a highly dynamic process that requires signaling from the extracellular matrix to the fibroblasts for migration and proliferation, and closure of the wound. This rate of wound closure is impaired in diabetes, which may be due to the increased levels of the precursor for advanced glycation end products, 3-deoxyglucosone (3DG). Previous studies suggest a differential role for p38 mitogen-activated kinase (MAPK) during wound healing; whereby, p38 MAPK acts as a growth kinase during normal wound healing, but acts as a stress kinase during diabetic wound repair. Therefore, we investigated the signaling cross-talk by which p38 MAPK mediates wound healing in fibroblasts cultured on native collagen and 3DG-collagen.

Methodology/Principal Findings

Using human dermal fibroblasts cultured on 3DG-collagen as a model of diabetic wounds, we demonstrated that p38 MAPK can promote either cell growth or cell death, and this was dependent on the activation of AKT and ERK1/2. Wound closure on native collagen was dependent on p38 MAPK phosphorylation of AKT and ERK1/2. Furthermore, proliferation and collagen production in fibroblasts cultured on native collagen was dependent on p38 MAPK regulation of AKT and ERK1/2. In contrast, 3DG-collagen decreased fibroblast migration, proliferation, and collagen expression through ERK1/2 and AKT downregulation via p38 MAPK.

Conclusions/Significance

Taken together, the present study shows that p38 MAPK is a key signaling molecule that plays a significantly opposite role during times of cellular growth and cellular stress, which may account for the differing rates of wound closure seen in diabetic populations.