Healing responses of skin and muscle in critical illness

β-Glucan "Trained Immunity" Immunomodulatory Properties Potentiate Tissue Wound Management and Accelerate Fitness Recover

Introduction

It is well established that moderate physical activity can improve the immune status, rather excess or high-intensity physical exercise can cause damage to the immune system. In addition, muscle injuries resulting from increased frequency and intensity of exercises compromise innate immune activity and may decrease tissue regeneration. Thus, β-glucans, a natural compound, may represent an important substance with strong immunomodulatory properties acting as an immunostimulant therapy known as "trained immunity". This immune stimulating therapeutic is an immunological memory phenomenon linked to the innate immune system, triggering cellular changes at epigenetic, transcriptional, and functional levels, to regulate the immune system and recover its homeostasis with clinical benefits.

Conclusion

This narrative review works with the current evidence regarding β-glucans as a possible alternative therapy for wound healing and its safety and efficacy in the treatment of muscle injuries and physical recovery including other chronic conditions and diseases.

Advances in Immunomodulation and Immune Engineering Approaches to Improve Healing of Extremity Wounds

Delayed healing of traumatic wounds often stems from a dysregulated immune response initiated or exacerbated by existing comorbidities, multiple tissue injury or wound contamination. Over decades, approaches towards alleviating wound inflammation have been centered on interventions capable of a collective dampening of various inflammatory factors and/or cells. However, a progressive understanding of immune physiology has rendered deeper knowledge on the dynamic interplay of secreted factors and effector cells following an acute injury. There is a wide body of literature, both in vitro and in vivo, abstracted on the immunomodulatory approaches to control inflammation. Recently, targeted modulation of the immune response via biotechnological approaches and biomaterials has gained attention as a means to restore the pro-healing phenotype and promote tissue regeneration. In order to fully realize the potential of these approaches in traumatic wounds, a critical and nuanced understanding of the relationships between immune dysregulation and healing outcomes is needed. This review provides an insight on paradigm shift towards interventional approaches to control exacerbated immune response following a traumatic injury from an agonistic to a targeted path. We address such a need by (1) providing a targeted discussion of the wound healing processes to assist in the identification of novel therapeutic targets and (2) highlighting emerging technologies and interventions that utilize an immunoengineering-based approach. In addition, we have underscored the importance of immune engineering as an emerging tool to provide precision medicine as an option to modulate acute immune response following a traumatic injury. Finally, an overview is provided on how an intervention can follow through a successful clinical application and regulatory pathway following laboratory and animal model evaluation.

Growth factor expression is enhanced and extracellular matrix proteins are depressed in healing skin wounds in septic patients compared with healthy controls

Sepsis manifests as a dysregulated immune response to infection, damaging organs. Skin has a critical role in protecting the body. In sepsis, skin wound healing is impaired. The mechanisms behind it have been poorly studied. In this study, suction blister wounds were induced on intact abdominal skin in 15 septic patients. A single blister wound was biopsied from each patient and from 10 healthy controls. Immunohistochemical staining of growth factors and extracellular matrix (ECM) proteins was performed. Significance (p < 0.05) of the differences was calculated. The following growth factors were overexpressed in the skin of septic patients compared with healthy controls: epithelial growth factor (intact epithelium p = 0.007, migrating epithelium p = 0.038), vascular epithelial growth factor (intact epithelium p < 0.001, migrating epithelium p = 0.011) and transforming growth factor beta (migrating epithelium p = 0.002). The expression of syndecan‐1 was upregulated in the skin of septic patients compared with healthy controls (intact epithelium p = 0.048, migrating epithelium p = 0.028). The following ECM proteins had lower expression in the epithelium in septic patients than in healthy controls: tenascin‐C (migrating epithelium p = 0.03) and laminin‐332 (intact epithelium p = 0.036). In sepsis, growth factor and syndecan expression was enhanced, while ECM and basement membrane proteins were mostly depressed.

Bedside determination of microcirculatory oxygen delivery and uptake: a prospective observational clinical study for proof of principle

Assessment of microcirculatory functional capacity is considered to be of prime importance for therapy guidance and outcome prediction in critically ill intensive care patients. Here, we show determination of skin microcirculatory oxygen delivery and consumption rates to be a feasible approach at the patient’s bedside. Real time laser-doppler flowmetry (LDF) and white light spectrophotometry (WLS) were used for assessment of thenar skin microperfusion, regional Hb and postcapillary venous oxygen saturation before and after forearm ischemia. Adapted Fick’s principle equations allowed for calculation of microcirculatory oxygen delivery and uptake. Patient groups with expected different microcirculatory status were compared [control (n = 20), sepsis-1/2 definition criteria identified SIRS (n = 10) and septic shock patients (n = 20), and the latter group further classified according to sepsis-3 definition criteria in sepsis (n = 10) and septic shock (n = 10)], respectively. In otherwise healthy controls, microcirculatory oxygen delivery and uptake approximately doubled after ischemia with maximum values (mDO2max and mVO2max) significantly lower in SIRS or septic patient groups, respectively. Scatter plots of mVO2max and mDO2max values defined a region of unphysiological low values not observed in control but in critically ill patients with the percentage of dots within this region being highest in septic shock patients. LDF and WLS combined with vasoocclusive testing reveals significant differences in microcirculatory oxygen delivery and uptake capacity between control and critically ill patients. As a clinically feasible technique for bedside determination of microcirculatory oxygen delivery and uptake, LDF and WLS combined with vasoocclusive testing holds promise for monitoring of disease progression and/or guidance of therapy at the microcirculatory level to be tested in further clinical trials.

ClinicalTrials.gov: NCT01530932.

Inhibitory effects of serum from sepsis patients on epithelial cell migration in vitro: a case control study

Background

Sepsis delays wound re-epithelialization. In this study we explored the effect of human sepsis sera as well as the effects of cytokines, growth factors and exosomes of sepsis sera treated normal fibroblasts (NF) on keratinocyte migration and proliferation in vitro.

Methods

Serum samples were taken on days 1, 4, and 9 from 44 patients diagnosed with severe sepsis, and from 14 matching healthy controls. We evaluated the effects of sepsis serum with or without TNF-α, EGF, EGF receptor inhibitor or exosomes of sepsis sera treated NF on human keratinocyte (HaCaT) proliferation (BrdU assay), viability (MTT assay), and migration (horizontal wound healing model). Cytokine levels of sepsis and healthy sera were measured by multiplex assay. Comparisons between groups were carried out using SPSS statistics and P < 0.05 was considered significant.

Results

Severe-sepsis sera collected on days 1, 4, and 9 reduced keratinocyte proliferation by 6% (P = 0.005), 20% (P = 0.001), and 18% (P = 0.002), respectively, compared to control sera. Cell viability in cultures exposed to sepsis sera from days 4 and 9 was reduced by 38% (P = 0.01) and 58% (P < 0.001), respectively. Open-surface wounds exposed to sepsis sera from days 1 and 4 were larger than those exposed to sera from healthy controls (60 vs. 31%, P = 0.034 and 66 vs. 31%, P = 0.023, respectively). Exosomes of sepsis or healthy sera treated NF inhibited keratinocyte migration. We detected higher serum levels of cytokines TNF-α (5.7 vs. 0.7 pg/ml, P < 0.001), IL-6 (24.8 vs. 3.8 pg/ml, P < 0.001), IL-10 (30.0 vs. 11.9 pg/ml, P = 0.040), and VEGF (177.9 vs. 48.1 pg/ml, P = 0.018) in sepsis sera. Levels of EGF were significantly lower in sepsis sera than in that of healthy controls (6.5 vs. 115.6 pg/ml, P < 0.001). Sepsis serum supplemented with EGF 5 ng/ml and TNF-α in all concentrations improved keratinocyte migration.

Conclusions

Keratinocyte viability, proliferation and migration were reduced in severe sepsis in vitro. Exosomes from NF added in healthy or sepsis serum media inhibited keratinocyte migration. Decreased levels of EGF in sepsis sera may partially explain the delay of wound healing with severe-sepsis patients. Increased levels of TNF-α in sepsis sera do not explain diminished keratinocyte migration.

Association of Microcirculation, Macrocirculation, and Severity of Illness in Septic Shock: A Prospective Observational Study to Identify Microcirculatory Targets Potentially Suitable for Guidance of Hemodynamic Therapy

PURPOSE

Clinically unapparent microcirculatory impairment is common and has a negative impact on septic shock, but specific therapy is not established so far. This prospective observational study aimed at identifying candidate parameters for microcirculatory-guided hemodynamic therapy. ClinicalTrials.gov : NCT01530932.

MATERIALS AND METHODS

Microcirculatory flow and postcapillary venous oxygen saturation were detected during vaso-occlusive testing (VOT) on days 1 (T0), 2 (T24), and 4 (T72) in 20 patients with septic shock at a surgical intensive care unit using a laser Doppler spectrophotometry system (O2C).

RESULTS

Reperfusional maximal venous capillary oxygen saturation (SvcO₂max) showed negative correlations with Simplified Acute Physiology Score II (SAPSII)/Sequential Organ Failure Assessment (SOFA) score, norepinephrine dosage, and lactate concentration and showed positive correlations with cardiac index (CI). At T24 and T72, SvcO₂max was also inversely linked to fluid balance. With respect to any predictive value, SvcO₂max and CI determined on day 1 (T0) were negatively correlated with SAPS II/SOFA on day 4 (T72). Moreover, SvcO₂max measured on day 1 or day 2 was negatively correlated with cumulated fluid balance on day 4 ( r= -.472, P < .05 and r = -.829, P < .001). By contrast, CI neither on day 1 nor on day 2 was correlated with cumulated fluid balance on day 4 ( r = -.343, P = .17 and r = -.365, P = .15).

CONCLUSION

In patients with septic shock, microcirculatory reserve as assessed by SvcO₂max following VOT was impaired and negatively correlated with severity of illness and fluid balance. In contrast to CI, SvcO₂max determined on day 1 or day 2 was significantly negatively correlated with cumulative fluid balance on day 4. Therefore, early microcirculatory measurement of SvcO₂max might be superior to CI in guidance of sepsis therapy to avoid fluid overload. This has to be addressed in future clinical studies.

Palliative Wound Care at the End of Life

Wound care, a form of palliative care, supports the health care needs of dying patients by focusing on alleviating symptoms. Although wound care can be both healing and palliative, it can impair the quality of the end of life for the dying if it is done without proper consideration of the patient’s wishes and best interests. Wound care may be optional for dying patients. This article will discuss the ethical responsibilities and challenges of providing wound care for surgical wounds, pressure ulcers, and wounds associated with cancer as well as wound care in home health compared to end of life.

Dermal expression of laminin-332 and type IV collagen in humans with severe sepsis

BACKGROUND

An intact basement membrane at the dermal-epidermal junction is essential to the viability of the skin. The effect of sepsis on the basement membrane is unknown.

METHODS

Skin biopsies were used to study basement membrane structure in severe sepsis (Day 1). Subsequent biopsies were taken on Day 8 and at 3 months in the survivors. Immunohistochemical staining was undertaken using laminin-223 and type IV collagen. Twenty patients with severe sepsis and four control subjects were included in the analysis.

RESULTS

Intensive care unit mortality was 4/20, and total 30-day mortality was 5/20. Exactly, 7/17 of patients with severe sepsis exhibited weak or absent laminin-332 expression and 11/15 exhibited weak or absent type IV collagen expression compared with 0/4 of control subjects on Day 1 in intact skin. The proportion of sepsis patients with weak or absent laminin-332 expression was 5/11 on Day 8 and fell to 1/7 at 3 months. The proportion of sepsis patients with weak or absent type IV collagen expression was 10/11 on Day 8 and 4/7 at 3 months.

CONCLUSION

These findings suggest that basement membrane formation may be compromised in patients with severe sepsis.

Subepidermal moisture surrounding pressure ulcers in persons with a spinal cord injury: a pilot study

OBJECTIVE

Characterization of a non-invasive method of quantifying subepidermal moisture (SEM) surrounding stages III and IV pressure ulcers (PrUs) in spinal cord injury (SCI).

DESIGN

Prospective, single-visit, single-rater, observational study, using repeated-measures analysis. Method Setting-inpatient units of one VA SCI Center.

PARTICIPANTS

Convenience sample of 16 subjects with SCI with stage III or IV PrUs over sacrum or ischium. Interventions Measurement with the MoistureMeter-D, a hand-held device using 300 MHz electromagnetic waves. Outcome measures Dielectric constant, a dimensionless number which increases with the moisture content. Each subject had a PrU site and a control site. Measurements were made at each site, on intact skin, at four points spaced angularly around the site, in triplicate. Results (1) Short-term, single-rater relative error was 2.5%. (2) Order effect: first readings were higher than second readings in 55 of 64 measurement sets. Order effect was significant for control sites (P < 0.0001) but not for PrU sites. (3) Angular effect: SEM varied by angle at the PrU sites (P < 0.01); 12 o'clock position the highest and 6 o'clock the lowest. (4) Ability to differentiate PrUs from intact skin: SEM at PrU sites was greater by 9.0% than control sites (P < 0.05). (5) Site effect: SEM was higher at sacral locations than ischial at control sites by 20% (P < 0.005).

CONCLUSIONS

SEM differentiates PrUs from intact skin. Future study designs must take into account order, angular, and site effects on this measure. This information will inform designers of future studies of SEM in healing of PrUs.

Severe blunt muscle trauma in rats: only marginal hypoxia in the injured area

Background

After severe muscle trauma, hypoxia due to microvascular perfusion failure is generally believed to further increase local injury and to impair healing. However, detailed analysis of hypoxia at the cellular level is missing. Therefore, in the present work, spectroscopic measurements of microvascular blood flow and O₂ supply were combined with immunological detection of hypoxic cells to estimate O₂ conditions within the injured muscle area.

Materials and Methods

Severe blunt muscle trauma was induced in the right Musculus gastrocnemius of male Wistar rats by a standardized “weight-drop” device. Microvascular blood flow, relative hemoglobin amount, and hemoglobin O₂ saturation were determined by laser Doppler and white-light spectroscopy. Hypoxic cells were detected by histologic evaluation of covalent binding of pimonidazole and expression of HIF-1α.

Results

Directly after trauma and until the end of experiment (480 minutes), microvascular blood flow and relative hemoglobin amount were clearly increased. In contrast to blood flow and relative hemoglobin amount, there was no immediate but a delayed increase of microvascular hemoglobin O₂ saturation. Pimonidazole immunostaining revealed a hypoxic fraction (percentage area of pimonidazole-labelled muscle cells within the injured area) between 8 to 3%. There was almost no HIF-1α expression detectable in the muscle cells under each condition studied.

Conclusions

In the early phase (up to 8 hours) after severe blunt muscle trauma, the overall microvascular perfusion of the injured area and thus its O₂ supply is clearly increased. This increased O₂ supply is obviously sufficient to ensure normoxic (or even hyperoxic) conditions in the vast majority of the cells.

An evaluation of differences in risk factors for individual types of surgical site infections after colon surgery

BACKGROUND

Most studies and national programs aggregate the different types of surgical site infections (SSIs) potentially masking and misattributing risk. Determining that risk factors for superficial, deep, and organ space SSIs are unique is essential to improve SSI rates.

METHODS

This cohort study utilized data of 59,365 patients who underwent colon resection at hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program from 2007 to 2009. Four independent, multivariable, predictive models were developed to assess the unique associations between risk factors and each SSI group: Superficial, deep, organ space, and an aggregate of all 3 types of SSIs.

RESULTS

Overall, 13% of colon cases developed SSIs: Superficial (8%), deep (1.4%), and organ space (3.8%). Each model was different. Morbidly obese patients were more likely to develop SSIs than normal weight patients across all models; however, risk factors common to all models (eg, body mass index [BMI], duration of operation, wound class, laparoscopic approach) had very different levels of risk. Unique risks for superficial SSIs include diabetes, chronic obstructive pulmonary disease, and dyspnea. Deep SSIs had the greatest magnitude of association with BMI and the greatest incidence of wound disruption (19.8%). Organ space SSIs were often owing to anastomotic leaks and were uniquely associated with disseminated cancer, preoperative dialysis, preoperative radiation treatment, and a bleeding disorder, suggesting a physically frail or compromised patient may put the anastomosis at risk.

CONCLUSION

Risk factors for superficial, deep, and organ space SSI differ. More effective prevention strategies may be developed by reporting and examining each type of SSI separately.

The open abdomen and temporary abdominal closure systems--historical evolution and systematic review

AIM

Several techniques for temporary abdominal closure have been developed. We systematically review the literature on temporary abdominal closure to ascertain whether the method can be tailored to the indication.

METHOD

Medline, Embase, the Cochrane Central Register of Controlled Trials and relevant meeting abstracts until December 2009 were searched using the following headings: open abdomen, laparostomy, VAC (vacuum assisted closure), TNP (topical negative pressure), fascial closure, temporary abdominal closure, fascial dehiscence and deep wound dehiscence. The data were analysed by closure technique and aetiology. The primary end-points included delayed fascial closure and in-hospital mortality. The secondary end-points were intra-abdominal complications.

RESULTS

The search identified 106 papers for inclusion. The techniques described were VAC (38 series), mesh/sheet (30 series), packing (15 series), Wittmann patch (eight series), Bogotá bag (six series), dynamic retention sutures (three series), zipper (15 series), skin only and locking device (one series each). The highest facial closure rates were seen with the Wittmann patch (78%), dynamic retention sutures (71%) and VAC (61%).

CONCLUSION

Temporary abdominal closure has evolved from simple packing to VAC based systems. In the absence of sepsis Wittmann patch and VAC offered the best outcome. In its presence VAC had the highest delayed primary closure and the lowest mortality rates. However, due to data heterogeneity only limited conclusions can be drawn from this analysis.

Classification of dermatological disorders in critical care patients: a prospective observational study

PURPOSE

The objective of this study was to identify dermatological disorders detected in the intensive care unit (ICU), to analyze their specific characteristics, and to define a useful classification for intensive care physicians.

MATERIALS AND METHODS

This was a prospective, observational study over a 3-year period (2006-2009) in a mixed ICU. This included all patients presenting with dermatological disorders that were detected at the time of ICU admission or developed along the ICU stay. We recorded the specific characteristics of the disorders and its evolution and treatment, which enabled us to classify the different observed conditions. As general variables, we analyzed demographic factors, the principal diagnosis, ICU procedures, the severity score (Acute Physiology and Chronic Health Evaluation II), length of stay, and mortality.

RESULTS

One hundred thirty-three patients showed at least one dermatological disorder (9.3%) and were classified into (1) preexisting dermatological disorders, (2) life-threatening dermatologic disorders, (3) systemic dermatological disorders, (4) infectious dermatological disorders, (5) reactive dermatological disorders, and (6) others.

CONCLUSIONS

Dermatological disorders are a frequent problem in the ICU, and their recognition is key to set up an appropriate care plan. We propose a classification and description of the different types of dermatological disorders that are most commonly found in ICUs.

ROS constitute a convergence nexus in the development of IGF1 resistance and impaired wound healing in a rat model of type 2 diabetes

An indolent non-healing wound and insulin and/or insulin-like growth factor (IGF1) resistance are cardinal features of diabetes, inflammation and hypercortisolemia. Little is known about why these phenomena occur in so many contexts. Do the various triggers that induce insulin and/or IGF1 resistance and retard wound healing act through a common mechanism? Cultured dermal fibroblasts from rats and full-thickness excisional wounds were used as models to test the premise that reactive oxygen species (ROS) play a causal role in the development of IGF1 resistance and impaired wound healing under different but pathophysiologically relevant clinical settings, including diabetes, dexamethasone-induced hypercortisolemia and TNFα-induced inflammation. In normal fibroblasts, IGF1 initiated a strong degree of phosphorylation of insulin receptor substrate 1 (IRS1) (Tyr612) and Akt (Ser473), concomitantly with increased PI3K activity. This phenomenon seemed to be attenuated in fibroblasts that had phenotypic features of diabetes, inflammation or hypercortisolemia. Notably, these cells also exhibited an increase in the activity of the ROS–phospho-JNK (p-JNK)–p-IRS1 (Ser307) axis. The above-mentioned defects were reflected functionally by attenuation in IGF1-dependent stimulation of key fibroblast functions, including collagen synthesis and cell proliferation, migration and contraction. The effects of IGF1 on glucose disposal and cutaneous wound healing were also impaired in diabetic or hypercortisolemic rats. The ROS suppressors EUK-134 and α-lipoic acid, or small interfering RNA (siRNA)-mediated silencing of JNK expression, restored IGF1 sensitivity both in vitro and in vivo, and also ameliorated the impairment in IGF1-mediated wound responses during diabetes, inflammation and hypercortisolemia. Our data advance the notion that ROS constitute a convergence nexus for the development of IGF1 resistance and impaired wound healing under different but pathophysiologically relevant clinical settings, with a proof of concept for the beneficial effect of ROS suppressors.

Trauma-activated polymorphonucleated leukocytes damage endothelial progenitor cells: probable role of CD11b/CD18-CD54 interaction and release of reactive oxygen species

Endothelial progenitor cells (EPCs) and polymorphonucleated leukocytes (PMNLs) migrate to and accumulate at the site of tissue injury where they express complementary sets of surface receptors (CD11b/CD18, CD54), suggesting a possible cellular interaction. Trauma-activated PMNLs release inflammatory mediators and reactive oxygen species (ROS) produced by the NADPH oxidase, which may negatively impact EPCs. To characterize the interactions between PMNLs and EPCs, we identified common surface receptors and measured the role played by NADPH oxidase and neutrophil elastase. Polymorphonucleated leukocytes were obtained from either healthy volunteers or multiple-trauma patients. After stimulation with either n-formyl-l-methionyl-l-leucyl-l-phenylalanine or phorbol 12-myristate 13-acetate, the PMNLs were incubated with DiL-prestained EPCs in a ratio of 20:1 for 3 h. Early EPCs were isolated from buffy coat. Endothelial progenitor cell killing was measured by flow cytometry, and necrotic EPCs were identified by measuring the uptake of 7-aminoactinomycin. We found that blocking CD11b, CD18, or CD54 on the EPC surface with monoclonal antibodies or blocking the intracellular production of ROS by neutralizing neutrophil's NADPH oxidase with a diphenyliodonium chloride pretreatment protected EPCs, enhancing its survival, whereas inhibiting neutrophil elastase had no effect on survival. Furthermore, we observed that native PMNLs obtained from multiple-trauma patients damaged EPCs, whereas native PMNLs from healthy volunteers did not. Our results demonstrate that EPCs and PMNLs do interact via complementary receptors and that this interaction results in PMNL-derived ROS-induced EPC damage. The effect of neutrophil-derived elastase was found to be negligible. These findings suggest that EPC damage by activated PMNLs may contribute to impaired wound healing observed after severe trauma.

A synthetic uric acid analog accelerates cutaneous wound healing in mice

Wound healing is a complex process involving intrinsic dermal and epidermal cells, and infiltrating macrophages and leukocytes. Excessive oxidative stress and associated inflammatory processes can impair wound healing, and antioxidants have been reported to improve wound healing in animal models and human subjects. Uric acid (UA) is an efficient free radical scavenger, but has a very low solubility and poor tissue penetrability. We recently developed novel UA analogs with increased solubility and excellent free radical-scavenging properties and demonstrated their ability to protect neural cells against oxidative damage. Here we show that the uric acid analog (6, 8 dithio-UA, but not equimolar concentrations of UA or 1, 7 dimethyl-UA) modified the behaviors of cultured vascular endothelial cells, keratinocytes and fibroblasts in ways consistent with enhancement of the wound healing functions of all three cell types. We further show that 6, 8 dithio-UA significantly accelerates the wound healing process when applied topically (once daily) to full-thickness wounds in mice. Levels of Cu/Zn superoxide dismutase were increased in wound tissue from mice treated with 6, 8 dithio-UA compared to vehicle-treated mice, suggesting that the UA analog enhances endogenous cellular antioxidant defenses. These results support an adverse role for oxidative stress in wound healing and tissue repair, and provide a rationale for the development of UA analogs in the treatment of wounds and for modulation of angiogenesis in other pathological conditions.

Consequences of surgical stress on the kinetics of skin wound healing: partial hepatectomy delays and functionally alters dermal repair

The objective was to determine the significance of surgical trauma in dermal wound healing. Using intravital microscopy, we analyzed the healing kinetics of full-thickness dermal wounds in the ears of SKH1 mice. Partial hepatectomy (pHx) simulated major surgical trauma, while laparotomy only served as a sham operation (sham). Animals without abdominal surgery served as controls (control). Laparotomy wounds were analyzed for biomechanical qualities and collagen deposition. Morphological characterization of skin repair was performed by histology/immunohistochemistry. In vitro cell assays assessed the paracrine effects of surgical stress. PHx caused a transient increase in tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 levels and led to weight loss, reflecting the host's overall response to surgery. Wound closure in pHx animals was delayed vs. control and sham animals, as indicated by significantly lower values of epithelialization and neovascularization over 10 days. Ear wound histology further revealed a provisional wound matrix with a reduced microvessel density. Moreover, pHx-laparotomy wounds showed a reduced bursting strength coexisting with significantly decreased collagen content. PHx and sham serum caused a significant alteration in in vitro fibroblast viability. Skin healing is dependent on the extent of surgery and is influenced by its paracrine effects. Therefore, considerable effort should be focused on the development of strategies limiting surgery-associated perturbations of dermal repair.

Epidermal wound healing in severe sepsis and septic shock in humans

Introduction

The effect of sepsis on epidermal wound healing has not been previously studied. It was hypothesised that epidermal wound healing is disturbed in severe sepsis.

Methods

Blister wounds were induced in 35 patients with severe sepsis and in 15 healthy controls. The healing of the wounds was followed up by measuring transepidermal water loss and blood flow in the wound, reflecting the restoration of the epidermal barrier function and inflammation, respectively. The first set of suction blisters (early wound) was made within 48 hours of the first sepsis-induced organ failure and the second set (late wound) four days after the first wound. In addition, measurements were made on the intact skin.

Results

The average age of the whole study population was 62 years (standard deviation [SD] 12). The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score on admission was 25 (SD 8). The two most common causes of infections were peritonitis and pneumonia. Sixty-six percent of the patients developed multiple organ failure. The decrease in water evaporation from the wound during the first four days was lower in septic patients than in the control subjects (56 g/m² per hour versus 124 g/m² per hour, P = 0.004). On the fourth day, septic patients had significantly higher blood flow in the wound compared with the control subjects (septic patients 110 units versus control subjects 47 units, P = 0.001). No difference in transepidermal water loss from the intact skin was found between septic patients and controls. Septic patients had higher blood flow in the intact skin on the fourth and on the eighth day of study compared with the controls.

Conclusions

The restoration of the epidermal barrier function is delayed and wound blood flow is increased in patients with severe sepsis.

A rational approach to nutritional assessment

BACKGROUND & AIMS

Consensus regarding definitions of malnutrition and methods to assess nutritional state is lacking. We propose a definition and its operationalization.

METHODS

A definition was formulated on the basis of the pathophysiology of malnutrition, while reviewing the metabolic and physiological characteristics of different populations, considered to be malnourished. The definition was operationalized to yield measures to perform nutritional assessment.

RESULTS

Malnutrition was defined as "a subacute or chronic state of nutrition in which a combination of varying degrees of over- or undernutrition and inflammatory activity has led to a change in body composition and diminished function". Its operationalization led to four elements that may serve as the basis of nutritional assessment: (1) measurement of nutrient balance, (2) measurement of body composition, (3) measurement of inflammatory activity, and (4) measurement of muscle, immune and cognitive function. Most elements measured should be validated with gold standards; normal values should be obtained in different populations. Values obtained in people considered to be at nutritional risk should be related to outcome.

CONCLUSION

A definition is proposed that reflects the pathophysiology of malnutrition and that, when operationalized, will lead to measures reflecting this pathophysiology. Such an approach may yield comparable and reproducible rates and degrees of malnutrition in populations as well as in individuals.

A review of research examining the regulatory role of lymphocytes in normal wound healing

Lymphocytes play a distinct, regulatory role in normal wound healing through the secretion of lymphokines. This paper evaluates the current research on the regulatory role of lymphocytes and their secretions in normal wound healing.

Intragraft chimerism following composite tissue allograft

Until now, more than 35 hand transplants have been performed in humans and have generated much public interest. Cell traffic from the recipient into the graft, so-called intragraft chimerism, appears to play a major role in graft acceptance and graft rejection. Little is known about cell migration following extremity allografts. In this review, recent experimental studies are presented for intragraft chimerism of the extremity allograft. Technical tools for detecting recipient cells in the graft were: (1) immunohistochemistry, (2) karyotyping, (3) fluorescent in situ hybridization, (4) polymerase chain reaction, and (5) transgenic animals. This study demonstrates that recipient-derived cells gradually repopulate into grafted skin, bone tissues, bone marrow, and endothelial cells, but muscle, periosteum, and cartilage tissues retain donor cell origin.

High dosage of simvastatin reduces TNF-alpha-induced apoptosis of endothelial progenitor cells but fails to prevent apoptosis induced by IL-1beta in vitro

Endothelial progenitor cells (EPC) could provide a possible source for the improvement of neovascularization in injured tissues following multiple trauma. Recently, it became obvious that at least two types of EPC can be cultured from peripheral blood mononuclear cells. In this work we focused on the fraction of the easily accessible early EPC, which can be generated in clinically relevant amounts within 5 days. Periods of hyper-inflammation, systemic or local, often occur during a multiple trauma. Thus, this study was conducted to elucidate the influence of the prototypical proinflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha) on the survival of early EPC. In the past years it was observed that HMG-CoA reductase inhibitors (statins) exert protective effects during inflammatory processes. Therefore, the effect of a preconditioning of early EPC with simvastatin on the survival of EPC under proinflammatory conditions was tested as well. Incubation with 50 mu/mL TNF-alpha [0.45 ng/mL] or IL-1beta [0.25 ng/mL] resulted in a 3-fold (18.4 +/- 2.9%), respectively, 4-fold (25.5 +/- 3.4%) increase of apoptotic EPC in comparison to the untreated control (6.1 +/- 1.6%). In accordance, 24 h after the cytokines had been added, the EPC number per high power field decreased significantly. A preconditioning with simvastatin [25 microM] resulted in significant inhibition of the TNF-alpha-induced apoptosis, whereas the IL-1beta-mediated apoptosis was only slightly reduced. In conclusion, this study shows clearly that TNF-alpha and IL-1beta are harmful to early EPC and that the HMG-CoA reductase inhibitor simvastatin protects EPC from TNF-alpha- and eventually from IL-1beta-mediated apoptosis. These results suggest that simvastatin has protective effects on EPC survival and differentiation in a hyperinflammatory situation.

Donor Cell Repopulation of Whole-Limb Allografts in the Rat: Detection with Green Fluorescent Protein

BACKGROUND

Although cell traffic between donor and recipient has previously been observed during allogeneic organ transplantation, little is known about cell traffic following whole-limb allografting. Whole-limb grafts are composed of composite tissues, and thus cell repopulations of recipients may be different for each component. This study was conducted using green fluorescent protein (GFP) transgenic rats to define cell repopulation of whole-limb allografts.

METHODS

Twenty-four hind-limb allotransplants were performed across GFP-positive (Wistar background) and GFP-negative (Lewis) rats. Eighteen recipient animals were treated with continuous FK506 immunosuppression at a dose of 0.5 mg/kg/day up to 6 months after transplantation and assessed until 18 months posttransplantation. The expression of the GFP gene was examined under 489-nm excitation light and semiquantitatively assessed by polymerase chain reaction.

RESULTS

Allografted limbs showed acute rejection in nontreated recipients, but no rejection episodes occurred in FK506-treated recipients until 18 months posttransplantation. Intense GFP expression was noted in allotransplanted GFP-negative limbs at 18 months posttransplant. GFP expression was especially marked at the interfollicular epidermis in the skin component and the endothelial cells. Polymerase chain reaction using GFP-specific primers confirmed the presence of the GFP gene in these tissues. Allotransplanted GFP-positive limbs retained marked GFP expression at the muscle fiber.

CONCLUSIONS

The authors' results demonstrate that recipient-derived cells gradually migrate into grafted skin, endothelial cells, muscle, and bone marrow cells. Recipient-derived stem cells may contribute to this cell renewal within the graft. Repopulation of antigenic skin components in the graft with recipient cells may also help in avoiding rejection.

Delivery of plasmid DNA expression vector for keratinocyte growth factor-1 using electroporation to improve cutaneous wound healing in a septic rat model

We have previously shown that wound healing was improved in a diabetic mouse model of impaired wound healing following transfection with keratinocyte growth factor-1 (KGF-1) cDNA. We now extend these findings to the characterization of the effects of DNA plasmid vectors delivered to rats using electroporation (EP) in vivo in a sepsis-based model of impaired wound healing. To assess plasmid transfection and wound healing, gWIZ luciferase and PCDNA3.1/KGF-1 expression vectors were used, respectively. Cutaneous wounds were produced using an 8 mm-punch biopsy in Sprague-Dawley rats in which healing was impaired by cecal ligation-induced sepsis. We used National Institutes of Health image analysis software and histologic assessment to analyze wound closure and found that EP increased expression of gWIZ luciferase vector up to 53-fold compared with transfection without EP (p < 0.001). EP-assisted plasmid transfection was found to be localized to skin. Septic rats had a 4.7 times larger average wound area on day 9 compared with control (p < 0.001). Rats that underwent PCDNA3.1/KGF-1 transfection with EP had 60% smaller wounds on day 12 compared with vector without EP (p < 0.009). Quality of healing with KGF-1 vector plus EP scored 3.0 +/- 0.3 and was significantly better than that of 1.8 +/- 0.3 for treatment with vector alone (p < 0.05). We conclude that both the rate and quality of healing were improved with DNA plasmid expression vector for growth factor delivered with EP to septic rats.

Wound Healing: An Overview

Understanding wound healing today involves much more than simply stating that there are three phases: inflammation, proliferation, and maturation. Wound healing is a complex series of reactions and interactions among cells and "mediators." Each year, new mediators are discovered and our understanding of inflammatory mediators and cellular interactions grows. This article will attempt to provide a concise overview on wound healing and wound management.

Effects of perioperative antiinflammatory and immunomodulating therapy on surgical wound healing

Patients with various rheumatologic and inflammatory disease states commonly require drugs known to decrease the inflammatory or autoimmune response for adequate control of their condition. Such drugs include nonsteroidal antiinflammatory drugs (NSAIDs), cyclooxygenase (COX)-2 inhibitors, corticosteroids, disease-modifying antirheumatic drugs (DMARDs), and biologic response modifiers. These drugs affect inflammation and local immune responses, which are necessary for proper wound healing in the perioperative setting, thereby potentially resulting in undesirable postoperative complications. Such complications include wound dehiscence, infection, and impaired collagen synthesis. The end result is delayed healing of soft tissue and bone wounds. The current literature provides insight into the effect of some of these drugs on wound healing. For certain drugs, such as methotrexate, trials have been conducted in humans and direct us on what to do during the perioperative period. Whereas with other drugs, we must rely on either small-animal studies or extrapolation of data from human studies that did not specifically look at wound healing. Unfortunately, no clear consensus exists on the need and optimum time for withholding therapy before surgery. Likewise, clinicians are often uncertain of the appropriate time to resume therapy after the procedure. For those drugs with limited or no data in this setting, the use of pharmacokinetic properties and biologic effects of each drug should be considered individually. In some cases, discontinuation of therapy may be required up to 4 weeks before surgery because of the long half-lives of the drugs. In doing so, patients may experience an exacerbation or worsening of disease. Clinicians must carefully evaluate individual patient risk factors, disease severity, and the pharmacokinetics of available therapies when weighing the risks and benefits of discontinuing therapy in the perioperative setting.

Residual congenital cystic adenomatoid malformation and thoracic scar deformation after fetal surgery: a case report

Fetal surgery is a treatment option for fetuses with congenital cystic adenomatoid malformation (CCAM) of the lung who develop hydrops before 32 weeks of gestation. We report on a fetus with CCAM and hydrops who underwent subtotal resection of a huge right, lower lobe CCAM at 20 weeks of gestation. Postnatally, the infant developed a thoracic scar deformation and was suspected to have residual CCAM. The residual CCAM was resected and the chest wall deformity was corrected at 3 1/2 years of age.

CO2 laser-resurfacing: Increased risk of side effects after uv-exposure?an experimental animal study

BACKGROUND AND OBJECTIVES

Carbon dioxide (CO(2)) laser resurfacing is primarily performed on photodamaged facial skin where patients are further exposed to ultraviolet radiation (UVR) postoperatively. We examined whether pre- and postoperative UVR influences the development of CO(2) laser-induced side effects.

STUDY DESIGN/MATERIALS AND METHODS

Hairless mice (n = 211) were treated with a Sharplan CO(2) laser with FeatherTouch scanner. Simulated solar irradiation was administered either preoperatively or pre- and postoperatively. Skin end-points (wounds, texture changes, and pigmentary changes) were evaluated blinded by clinical evaluations, skin reflectance spectroscopy, and histological examinations.

RESULTS

Pre- and postoperative UVR exposed mice obtained higher clinical scores of wounds (P < 0.02) and texture changes (P < 0.01) and developed more heavy fibrosis than mice treated with laser but no UVR. UVR exposure after CO(2) laser treatment induced significant hyperpigmentation compared to unexposed control mice (P < 0.003), whereas CO(2) laser treatment itself did not induce pigmentary changes.

CONCLUSIONS

UVR increases in an animal model the occurrence of postoperative side effects from CO(2) laser resurfacing.

Cell traffic between donor and recipient following rat limb allograft

Although cell traffic from the graft into the recipient and from the recipient into the graft had been noticed in allogeneic organ transplantation, little is known following whole-limb allografting. This study was conducted to define cell migration between donor and recipient. Sixty-seven vascularized hind limb allotransplantations were performed in rat sex-mismatched pairs and the recipient animals were treated with FK506 immunosuppression. The ratio of donor and recipient cells was evaluated by semi-quantitative PCR using the specific primers of the Y-chromosome. Allografted limbs had no rejection episode until the final assessment. The male recipient cells were detected in female limb grafts not at 1 week but at 48 weeks after transplantation. The male donor cells were detected in the humerus and tibia in the female recipient but not in the gastrocnemius muscle and leg skin. Our results demonstrated that recipient-derived cells gradually migrated into the grafted bone, muscle and skin cells with the duration of time. Donor-derived cells migrated into the healthy bones but not into the healthy muscle and skin. Because active regeneration occurs in the grafted limb to compensate graft damage secondary to ischemia and operative intervention, recipient-derived cells may mediate a muscular and dermo-epidermal renewal.

The pragmatics of feeding the pediatric patient with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) represents the ultimate pulmonary response to a wide range of injuries, from septicemia to trauma. Optimal nutrition is vital to enhancing oxygen delivery, supporting adequate cardiac contractility and respiratory musculature, eliminating fluid and electrolyte imbalances, and supporting the proinflammatory response. Research is providing a better understanding of nutrients that specifically address the complex physiologic changes in ARDS. This article highlights the pathophysiology of ARDS as it relates to nutrition, relevant nutritional assessment, and important enteral and parenteral considerations for the pediatric patient who has ARDS.