Tumor necrosis factor binding protein improves incisional wound healing in sepsis

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.

11,12 Epoxyeicosatrienoic Acid Rescues Deteriorated Wound Healing in Diabetes

Epoxyeicosatrienoic acids (EET) facilitate regeneration in different tissues, and their benefit in dermal wound healing has been proven under normal conditions. In this study, we investigated the effect of 11,12 EET on dermal wound healing in diabetes. We induced diabetes by i.p. injection of streptozotocin 2 weeks prior to wound creation on the dorsal side of the mouse ear. 11,12 EET was applied every second day on the wound, whereas the control groups received only solvent. Epithelialization was monitored every second day intravitally up to wound closure. Wounds were stained for VEGF, CD31, TGF-β, TNF-α, SDF-1α, NF-κB, and Ki-67, and fibroblasts were counted after hematoxylin-eosin stain on days 3, 6, 9, and 16 after wounding. After induction of diabetes, wounds closed on day 13.00 ± 2.20 standard deviation (SD). Local 11,12 ETT application improved wound closure significantly to day 8.40 ± 1.39 SD. EET treatment enhanced VEGF and CD31 expression in wounds on day 3. It also seemed to raise TNF-α level on all days investigated as well as TGF-β level on days 3 and 6. A decrease in NF-κB could be observed on days 9 and 16 after EET application. The latter findings were not significant. SDF-1α expression was not influenced by EET application, and Ki-67 was significantly less in the EET group on day 9 after EET application. The number of fibroblasts was significantly increased on day 9 after the 11,12 EET application. 11,12 EET improve deteriorated wound healing in diabetes by enhancing neoangiogenesis, especially in the early phase of wound healing. Furthermore, they contribute to the dissolution of the initial inflammatory reaction, allowing the crucial transition from the inflammatory to proliferative phase in wound healing.

Management of Biological Therapy Before Elective Inflammatory Bowel Disease Surgeries

Increasing uptake of biologic therapy has contributed to declining surgical rates for inflammatory bowel disease (IBD). However, a significant number of patients on biologic therapy will go on to require surgery. The literature is conflicted with regard to the preoperative management of biologic therapy before urgent or elective IBD surgery. This article reviews the available data on postoperative complications following preoperative treatment with anti-tumor necrosis factor alpha therapy, anti-integrin therapy, and anti-interleukin therapy.

Anti-TNF and Postoperative Complications in Abdominal Crohn's Disease Surgery

Background: :

Biological therapy with anti-Tumour Necrosis Factor (TNF)-α agents revolutionised the treatment of inflammatory bowel disease over the last decades. However, there may be an increased risk of postoperative complications in Crohn’s disease (CD) patients treated with anti-TNF-α agents prior to abdominal surgery.

Objective::

To evaluate the effects of preoperative anti-TNF-α therapy on the incidence of complications after surgery.

Methods: :

A critical assessment of the results of clinical trial outcomes and meta-analyses on the available data was conducted.

Results: :

Based on the outcomes of previous reports including meta-analyses, preoperative use of anti- TNF-α agents modestly increased the risk of overall complications and particularly infectious complications after abdominal surgery for CD. Nevertheless, previous studies have several limitations. The majority of them were retrospective research with heterogeneous outcome measures and single centre trials with relatively small sample size. In retrospective studies, the standard protocol for assessing various types of postoperative complications was not used. The most serious limitation of the previous studies was that multiple confounding factors such as malnutrition, use of corticosteroids, and preoperative sepsis were not taken into consideration.

Conclusion::

Among patients treated with preoperative anti-TNF-α therapy, the risk of overall complications and infectious complications may slightly increase after abdominal surgery for CD. Nevertheless, the previous reports reviewed in this study suffered from limitations. To rigorously evaluate the risk of anti-TNF-α therapy prior to surgery, large prospective studies with standardised criteria for assessing surgical complications and with proper adjustment for confounding variables are warranted.

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.

The time course of cytokine expressions plays a determining role in faster healing of intestinal and colonic anastomatic wounds

OBJECTIVES

Inflammation is critical in the early phases of wound healing. It has been reported previously that small intestinal and colonic wounds display a more rapid healing than those of other organs. However, the underlying mechanism has not yet been elucidated. Here we examined whether differences in the time course of specified cytokine expression, in colonic and small intestinal anastomotic lesions, might play a major role in this observation in comparison to lesions effecting skin and muscle tissue.

MATERIALS AND METHODS

Tissue lesions were applied to 36 male Sprague-Dawley rats. Tissue samples were harvested at 1, 3, 5, 7, and 14 days postoperatively with the levels of TNF-α, IL-6, and IFN-α determined by ELISA-derived methods.

RESULTS

The characteristics of TNF-α, IL-6, and IFN-α expression during the healing process for intestinal and colonic lesions were comparable. However, data differed significantly with that observed during healing of skin and muscle lesions. Intestinal and colonic lesions exhibited a significant and sustained increase in specified cytokine levels on day 5 to day 14 as compared with day 1 and 3. Skin and muscle lesions had random or unaltered cytokine levels throughout the study period.

CONCLUSION

Differences in expression of cytokines TNF-α, IL-6, and IFN-α indicate that these play an important role underlying the more rapid healing processes observed in small intestinal and colonic lesions.

Nanofiber-expanded human umbilical cord blood-derived CD34+ cell therapy accelerates murine cutaneous wound closure by attenuating pro-inflammatory factors and secreting IL-10

Nanofiber-expanded human umbilical cord blood-derived CD34+ cell therapy is under consideration for treating peripheral and cardiac ischemia. However, the therapeutic efficacy of nanofiber-expanded human umbilical cord blood-derived (NEHUCB) CD34+ cell therapy for wound healing and its mechanisms are yet to be established. Using an excision wound model in NOD/SCID mice, we show herein that NEHUCB-CD34+ cells home to the wound site and significantly accelerate the wound-healing process compared to vehicle-treated control. Histological analysis reveals that accelerated wound closure is associated with the re-epithelialization and increased angiogenesis. Additionally, NEHUCB-CD34+ cell-therapy decreases expression of pro-inflammatory cytokines, such as TNF-α, IL-1β, IL-6 and NOS2A in the wound bed, and concomitantly increases expression of IL-10 compared to vehicle-treated control. These findings were recapitulated in vitro using primary dermal fibroblasts and NEHUCB-CD34+ cells. Moreover, NEHUCB-CD34+ cells attenuate NF-κB activation and nuclear translocation in dermal fibroblasts through enhanced secretion of IL-10, which is known to bind to NF-κB and suppress transcriptional activity. Collectively, these data provide novel mechanistic evidence of NEHUCB-CD34+ cell-mediated accelerated wound healing.

Delayed wound repair in sepsis is associated with reduced local pro-inflammatory cytokine expression

Sepsis is one of the main causes for morbidity and mortality in hospitalized patients. Moreover, sepsis associated complications involving impaired wound healing are common. Septic patients often require surgical interventions that in-turn may lead to further complications caused by impaired wound healing. We established a mouse model to the study delayed wound healing during sepsis distant to the septic focus point. For this reason cecal ligation and puncture (CLP) was combined with the creation of a superficial wound on the mouse ear. Control animals received the same procedure without CPL. Epithelialization was measured every second day by direct microscopic visualization up to complete closure of the wound. As interplay of TNF-α, TGF-β, matrix metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) is important in wound healing in general, TNF-α, TGF-β, MMP7, and TIMP1 were assessed immunohistochemical in samples of wounded ears harvested on days 2, 6, 10 and 16 after wounding. After induction of sepsis, animals showed a significant delay in wound epithelialization from day 2 to 12 compared to control animals. Complete wound healing was attained after mean 12.2± standard deviation (SD) 3.0 days in septic animals compared to 8.7± SD 1.7 days in the control group. Septic animals showed a significant reduction in local pro-inflammatory cytokine level of TNF-α on day 2 and day 6 as well as a reduced expression of TGF-β on day 2 in wounds. A significant lower expression of MMP7 as well as TIMP1 was also observed on day 2 after wounding. The induction of sepsis impairs wound healing distant to the septic focus point. We could demonstrate that expression of important cytokines for wound repair is deregulated after induction of sepsis. Thus restoring normal cytokine response locally in wounds could be a good strategy to enhance wound repair in sepsis.

Tumor necrosis factor-alpha (TNF-α) is a therapeutic target for impaired cutaneous wound healing

Impaired wound healing states lead to substantial morbidity and cost with treatment resulting in an expenditure of billions of dollars per annum in the U.S. alone. Both chronic wounds and impaired acute wounds are characterized by excessive inflammation, enhanced proteolysis, and reduced matrix deposition. These confounding factors are exacerbated in the elderly, in part, as we report here, related to increased local and systemic tumor necrosis factor-alpha (TNF-α) levels. Moreover, we have used a secretory leukocyte protease inhibitor (SLPI) null mouse model of severely impaired wound healing and excessive inflammation, comparable to age-related delayed human healing, to demonstrate that topical application of anti-TNF-α neutralizing antibodies blunts leukocyte recruitment and NFκB activation, alters the balance between M1 and M2 macrophages, and accelerates wound healing. Following antagonism of TNF-α, matrix synthesis is enhanced, associated with suppression of both inflammatory parameters and NFκB binding activity. Our data suggest that inhibiting TNF-α is a critical event in reversing the severely impaired healing response associated with the absence of SLPI, and may be applicable to prophylaxis and/or treatment of impaired wound healing states in humans.

Temporal expression of cytokines in rat cutaneous, fascial, and intestinal wounds: a comparative study

BACKGROUND

Previous studies have shown that healing in intestinal wounds is proportionally faster than skin. Cytokines and growth factors play a major role in these coordinated wound-healing events. We hypothesized that this more rapid intestinal healing is due to an early upregulation of proinflammatory cytokines (IL-1beta, TNF-alpha, and IFN-gamma), followed by increases in the expression of the anti-inflammatory cytokine IL-10 and growth factor TGF-beta.

METHODS

Four wounds (skin, fascia, small intestinal, and colonic anastomosis) were created in each of 48 juvenile male Sprague Dawley rats; tissue samples of each site were harvested at 0, 1, 3, 5, 7, and 14 days postoperatively (n = 8/group) and levels of IL-1beta, IFN-gamma, TNF-alpha, IL-10 and TGF-beta expression from each site were measured using ELISA kits.

RESULTS

IL-1beta expression peaked earlier in small-intestinal and colonic wounds when compared to skin or fascia (e.g., small intestine: day 3 and colon day 5, P < 0.05 by ANOVA). Post-wounding levels of TNF-alpha were elevated in fascial wounds, but decreased in small-intestinal and colonic wounds. IFN-gamma levels were not significantly altered in any wounds. IL-10 showed a similar downregulation pattern in all wounds, while TGF-B levels were decreased in colonic and fascial wounds, but relatively unchanged in SI and skin.

CONCLUSIONS

An earlier peak in IL-1beta levels and a consistent decrease in TNF-alpha were seen in healing intestinal tissues; but no clear pattern of increased anti-inflammatory or regulatory cytokines was seen, which might explain the earlier healing of intestinal tissues. Additional studies are required to determine the role of individual cytokines, or the intrinsic reactivity of the tissues may explain the site specific differences of healing rates in different tissues.

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.

Effect of blockade of tumor necrosis factor-alpha with etanercept on surgical wound healing in SWISS-OF1 mice

OBJECTIVE

To assess whether blockade of tumor necrosis factor-alpha (TNF-alpha) influences surgical wound healing in a normal mouse experimental model.

METHODS

Wound healing time course and degree of surgical wound collagenization were measured by morphological techniques and digital image analysis in 80 male SWISS-OF1 mice (40 received subcutaneous etanercept at a dose of 0.1 mg/25 g/ at -7, 0, 7, and 14 days).

RESULTS

No significant differences were observed between treated and untreated animals in wound healing, re-epithelialization, or formation of inflammatory infiltrate or granulation tissue at days 7, 15, or 20 after surgery. At 20 days, the collagen area was larger in treated versus untreated mice (109,029 +/- 28,489 microm(2) vs 79,305 +/- 19,798 microm(2), p = 0.026, Mann-Whitney U test).

CONCLUSION

Surgical wounds showed a higher degree of collagenization at 20 days in etanercept-treated versus untreated mice, with no differences in the time course of wound healing. These data suggest that biological therapies to block TNF-alpha do not affect wound healing and do not need to be suspended during the perioperative period.

Markers of collagen synthesis and degradation are increased in serum in severe sepsis: a longitudinal study of 44 patients

Introduction

Sepsis-related multiple organ dysfunction is a common cause of death in the intensive care unit. The effect of sepsis on markers of tissue repair is only partly understood. The aim of this study was to measure markers of collagen synthesis and degradation during sepsis and investigate the association with disease severity and outcome.

Methods

Forty-four patients with severe sepsis participated in the study and 15 volunteers acted as controls. Blood samples were collected for 10 days after the first sepsis-induced organ dysfunction and after three and six months. Procollagen type I and III aminoterminal propeptides (PINP and PIIINP) and cross-linked telopeptides of type I collagen (ICTP) were measured.

Results

The PIIINP concentration was elevated in the septic patients (8.8 ug/L, 25th to 75th percentile = 6.8 to 26.0) when compared with controls (3.0 ug/L, 25th to 75th percentile = 2.7 to 3.3; P < 0.001) on day one. Maximum serum PIIINP concentrations during sepsis were higher in non-survivors compared with survivors (26.1 ug/L, 25th to 75th percentile = 18.7 to 84.3; vs. 15.1 ug/L, 25th to 75th percentile = 9.6 to 25.5; P = 0.033) and in multiple organ failure (MOF) compared with multiple organ dysfunction syndrome (MODS) (24.2 ug/L, 25th to 75th percentile = 13.4 to 48.2; vs. 8.9 ug/L, 25th to 75th percentile = 7.4 to 19.4; P = 0.002). Although the PINP values of the septic patients remained within the laboratory reference values, patients with MOF had higher values than patients with MODS (79.8, 25th to 75th percentile = 44.1 to 150.0; vs.40.4, 25th to 75th percentile = 23.6 to 99.3; P = 0.007). Day one ICTP levels were elevated in septic patients compared with the controls (19.4 ug/L, 25th to 75th percentile = 12.0 to 29.8; vs. 4.1 ug/L, 25th to 75th percentile = 3.4 to 5.0; P < 0.001).

Conclusions

Markers of collagen metabolism are increased in patients with severe sepsis and can be investigated further as markers of disease severity and outcome.

Pro-inflammatory cytokine, matrix metalloproteinases and TIMP-1 are involved in wound healing after mastectomy in invasive breast cancer patients

BACKGROUND

Mastectomy provides a good model to study the wound healing process after surgery. The involved factors include selectins, pro-inflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), matrix metalloproteinases (MMPs), and their natural inhibitors (TIMPs). In the present study, we observed the kinetic changes of these factors in the process of wound healing after a mastectomy, and analyzed the relationship between these factors and the clinical outcomes.

MATERIALS AND METHODS

Twenty-nine patients, who received a modified radical mastectomy, were recruited to this study. The wound was inspected daily for the presence of flap necrosis, infection and seroma. Drain fluid was collected on days 1, 2 and 5. IL-6, P-selectin, MMP-2, 3, 9 and TIMP-1 were screened by ELISA kits for their impacts on wound healing after mastectomy.

RESULTS

IL-6 demonstrated the highest level on Day 1 after operation and was negatively correlated with MMP-2, which in turn showed a consistently negative correlation with MMP-9 for days 1, 2 and 5. Incidences of seroma formation and skin flap necrosis were 27.6% and 20.7%, respectively. Seroma formation was associated with low MMP-2 levels on Day 5. While skin flap necrosis seemed to correlate with high MMP-2 levels and low levels of MMP-9 and TIMP-1.

CONCLUSION

IL-6, P-selectin, MMP-2, MMP-3, MMP-9 and TIMP-1 are important in the process of wound healing after mastectomy. A low MMP-2 level correlates with the formation of seroma, while MMP-2, MMP-9 and TIMP-1 are associated with skin flap necrosis.

TNF-alpha suppresses alpha-smooth muscle actin expression in human dermal fibroblasts: an implication for abnormal wound healing

Abnormal wound healing encompasses a wide spectrum, from chronic wounds to hypertrophic scars. Both conditions are associated with an abnormal cytokine profile in the wound bed. In this study, we sought to understand the dynamic relationships between myofibroblast differentiation and mechanical performance of the collagen matrix under tissue growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha) stimulation. We found TGF-beta increased alpha-smooth muscle actin (alpha-SMA) and TNF-alpha alone decreased the basal alpha-SMA expression. When TGF-beta1 and TNF-alpha were both added, the alpha-SMA expression was suppressed below the baseline. Real-time PCR showed that TNF-alpha suppresses TGF-beta1-induced myofibroblast (fibroproliferative) phenotypic genes, for example, alpha-SMA, collagen type 1A, and fibronectin at the mRNA level. TNF-alpha suppresses TGF-beta1-induced gene expression by affecting its mRNA stability. Our results further showed that TNF-alpha inhibits TGF-beta1-induced Smad-3 phosphorylation via Jun N-terminal kinase signaling. Mechanical testing showed that TNF-alpha decreases the stiffness and contraction of the lattices after 5 days in culture. We proposed that changes in alpha-SMA, collagen, and fibronectin expression result in decreased contraction and stiffness of collagen matrices. Therefore, the balance of cytokines in a wound defines the mechanical properties of the extracellular matrix and optimal wound healing.

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.

Effect of plasma fibronectin on the incisional wound healing in rats

BACKGROUND

Abdominal wall repair after celiotomy is important because insufficient incisional wound strength results in wound failures such as fascial dehiscence and herniation. Plasma fibronectin (pFn) has been shown to play an important role in wound healing. The purpose of this study was to investigate whether pFn improves incisional wound healing in a rat skin incision and celiotomy model.

METHODS

Rats underwent a linear skin incision in the dorsal plane or a full-thickness incisional wound (celiotomy) in the abdominal wall. The same operative procedures were performed on rats whose pFn levels were reduced by antirat pFn serum. The wounds were sutured, and purified human pFn or albumin was given intravenously.

RESULTS

After the celiotomy, pFn levels decreased immediately and reached a minimum at 3 h after incision. A single injection of pFn (10 mg/kg) significantly increased the breaking strength of the skin and the bursting pressure of the abdominal wall. The amount of hydroxyproline in the skin incisional wound with pFn was significantly greater than with an injection of albumin as control. In rats with pFn levels decreased by antirat pFn serum, a single administration of pFn significantly increased the breaking strength of the skin and the bursting pressure of the abdominal wall compared to a control injection of albumin.

CONCLUSIONS

It is important for wound healing to maintain sufficiently high levels of pFn. A single intravenous injection of pFn after celiotomy may be useful in the prevention of fascial dehiscence and herniation.

Perioperative management of patients with rheumatoid arthritis in the era of biologic response modifiers

PURPOSE OF REVIEW

This article provides guidelines for the perioperative management of the most commonly used antirheumatic drugs being used to treat patients with rheumatoid arthritis, with an emphasis on the relatively new addition of biologic response modifiers.

RECENT FINDINGS

Few clinical data exist examining the perioperative management of the biologic drugs, which include the inhibitors of tumor necrosis factor-alpha (etanercept, infliximab, and adalimumab), the interleukin-1 receptor antagonist anakinra, and to a much lesser extent the CD20 inhibitor rituximab. The only human data available in that regard is based on the use of the tumor necrosis factor-alpha inhibitor infliximab in surgical patients with Crohn disease. Although quite limited, that data appeared favorable in finding that infliximab did not result in an increased risk of postoperative complications in that setting.

SUMMARY

Perioperative guidelines have never been well established for a majority of the traditional antirheumatic drugs in use today. Recommendations for the perioperative use of nonsteroidal antiinflammatory drugs and glucocorticoids have the most evidence-based support. Data for the use of methotrexate are also available from which to generate reasonable guidelines; however, for the remaining antirheumatic drugs in current use, the available data cannot support any clear evidence-based recommendations. To provide reasonable guidelines for the use of the biologics, perhaps the best we can do is to extrapolate from the very limited data coming from the concurrent use of infliximab in patients with Crohn disease who have undergone surgery. Beyond that, we are left with animal and tissue culture data from which any recommendations would be rather tenuous.

Cytokines and wound healing: the role of cytokine and anticytokine therapy in the repair response

Wound healing is an integrated and complex process involving a large number of regulatory molecules, including proinflammatory cytokines and growth factors, and an orchestrated tissue response. Dysregulation in cytokine or growth factor expression dramatically alters the normal wound healing process, and blocking the inappropriate production of specific proinflammatory cytokines or supplementing the milieu with increased quantities of growth factors has demonstrated the central role played by these mediators. Both protein-based and DNA-based (gene transfer) therapies are currently under clinical development as tools to improve the healing process. Although there has been some success with these approaches in both experimental models and in patients, only through a better understanding of the complexity and diversity of the wound healing process, as well as an improved comprehension of the time-dependent and concentration-dependent responses to individual proinflammatory cytokines or growth factors, will further development in the therapeutic treatment of healing wounds be attained.

The study of cytokine dynamics at the operation site after mastectomy

Twenty-nine patients, who each received modified radical mastectomy, were recruited for this study. Wounds were inspected daily for the presence of flap necrosis, infection, and seroma. Drain fluid (20 ml) was collected at 6 a.m. on postoperative days 1, 2, and 5 and the levels of interleukin (IL)-4, IL-6, tumor necrosis factor-alpha, and interferon-gamma determined. For patients with no wound events, only IL-6 levels were elevated during the initial phase, but in the later phase the IL-6 levels dropped with a corresponding rise in tumor necrosis factor-alpha levels. In patients with flap necrosis, there was a sequential rise of IL-4 on day 1, IL-6 on day 2, and tumor necrosis factor-alpha on day 5, but only IL-4 was found to be a statistically significant factor associated with necrosis. In patients with seroma, the levels of IL-4 and interferon-gamma were persistently low and were both statistically significant. To conclude, IL-6 and tumor necrosis factor-alpha are important in normal postoperative wound healing and IL-4 and interferon-gamma may be associated with postoperative necrosis and seroma.

Inflammatory mediators in wound healing

This article provides much evidence that the inflammatory process has direct effects on normal and abnormal wound healing. As better understanding develops for the mechanism for these outcomes, targeted proinflammatory and anti-inflammatory interventions are likely to be successful. When inflammation is maintained as a regulated and orchestrated response, effective and normal wound healing is likely to result.

Local expression of tumor necrosis factor-alpha and interleukin-10 on wound healing of intestinal anastomosis during endotoxemia in mice

BACKGROUND

This study aimed to evaluate the integrity of anastomotic wound healing after digestive surgery under septic conditions and define the participation of local expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) around the anastomotic segment.

MATERIALS AND METHODS

Experimental animals were divided into lipopolysaccharide (LPS) and control groups, which had either LPS or normal saline solution injected into the peritoneal cavity 24 h before transection and anastomosis of the colon. Anastomotic bursting pressure (ABP) and tissue hydroxyproline concentration (HP) were measured as indicators of wound healing. Immunohistochemical staining for TNF-alpha and IL-10 on tissue samples obtained from the anastomotic segment were examined 1, 6, and 24 h after the operation. The reactive cells were counted under light microscopy.

RESULTS

ABP and HP were significantly lower in the LPS group than in the control group 7 days after surgery. In the LPS group, TNF-alpha expression increased about threefold over that in the control group 1 h after the operation. TNF-alpha-reactive cells were observed until 24 h after the operation in the LPS group, but not in the control group. On the other hand, IL-10 was not expressed in the control group during the observed period, whereas IL-10 was observed 24 h after the operation in the LPS group.

CONCLUSIONS

It is suggested that anastomotic wound healing was impaired after the digestive surgery in animals treated with intraperitoneal LPS, and that local expression of TNF-alpha and IL-10 at the anastomotic site acts as an inhibitory factor in the wound healing process.

The effects of basic fibroblast growth factor (bFGF) on the breaking strength of acute incisional wounds

Many researchers have reported the effects of cytokines on ulcers, especially on chronic ulcers. However, the long-term influences of cytokines on acute incisional wounds with respect to breaking strength, quality of the scar etc. have not been elucidated completely. In the present study, the breaking strength of scars produced by full thickness incisional wounds of the skin created on backs of rabbits were compared when the wounds were treated by conventional suturing or with basic fibroblast growth factor (bFGF) in addition to suturing. We administered bFGF to full thickness acute incisional wounds of the skin created on backs of rabbits. The breaking strengths of wounds treated by conventional suturing and those treated with bFGF soon after the operation were compared as were the conditions of the scars after long-term follow up of up to 7 weeks. They were also examined histopathologically. Administration of bFGF at the time of wound closure, especially 1.0 microg in amount per cm, increased the breaking strength significantly compared to the control group from 5 weeks after the operation. Moreover, histopathological examination revealed that there was rich vascularization soon after the operation and an arrangement of collagen fibers which lenticulated horizontally from the 5th week and later after the operation in the bFGF treated groups in a dose dependent manner. This study demonstrates that administration of bFGF at the time of wound closure significantly increased the breaking strength compared to the control group from 5 weeks after the operation. And the administration of bFGF also improved the quality of the scar, the condition of the scar by surface condition by inspection as well as the width of scar at histological evaluations. So we think this cytokine may be highly effective clinically. This may be especially true for patients whose wound healing process tends to be delayed such as aged patients or when high breaking strength is recommended even for patients with normal wound healing potential.

Laser soldering of rat skin, using fiberoptic temperature controlled system

BACKGROUND AND OBJECTIVE

Laser soldering of tissues is based on the application of a biological solder on the approximated edges of a cut. Our goal was to use laser soldering for sealing cuts in skin under temperature feedback control and compare the results with ones obtained using standard sutures.

STUDY DESIGN/MATERIALS AND METHODS

Albumin solder was applied onto the approximated edges of cuts created in rat skin. A fiberoptic system was used to deliver the radiation of a CO(2) laser, to heat a spot near the cut edges, and to control the temperature. Laser soldering was carried out, spot by spot, where the temperature at each spot was kept at 65-70 degrees C for 10 sec.

RESULTS

The tensile strength of laser-soldered cuts was measured after 3-28 days postoperatively and was found comparable to that of sutured cuts. Histopathological studies showed no thermal damage and less inflammatory reaction than that caused by standard sutures (P = 0.04).

CONCLUSIONS

Temperature controlled laser soldering of cuts in rat skin gave strong bonding. The cosmetic and histological results were very good, in comparison to those of standard sutures.

Vanadate ingestion increases the gain in wound breaking strength and leads to better organized collagen fibers in rats during healing

Repair of incision wounds closed by suturing is evaluated by the progressive gain in wound breaking strength. Previously the closure of open wounds in rats ingesting vanadate, an inhibitor of tyrosine phosphate phosphatases, was shown to occur with deposition of more uniformly organized collagen fiber bundles. The hypothesis of this study was that deposition of more uniformly organized collagen fibers would enhance the gain in wound breaking strength of incisional wounds. Six adult rats received vanadate-supplemented saline drinking water for 1 week before placement of two 6-cm, parallel, suture-closed wounds on their backs. Six control rats received identical wounds and were given saline drinking water. The drinking water regimen was continued for 1 week after wounding, and then wound strength was tested with a tensiometer and tissue samples were obtained for histologic evaluation. Wound breaking strength doubled in vanadate-treated rats compared with controls. Bright-field and polarized light microscopy showed that the connective tissue matrix of granulation tissue from control rats was oriented perpendicular to the surface of the skin. In contrast, the connective tissue matrix of granulation tissue from vanadate-treated rats was oriented parallel to the skin surface. The gap in granulation tissue between the edges of the wounds in the vanadate-treated rats was greater than that in controls. Electron microscopy showed that wounds in the vanadate-treated contained uniform collagen fibers that were 20 percent greater in diameter and more evenly spaced than they were in controls. It is proposed that these changes in the organization of collagen fibers within incisional wounds were responsible for the increased wound breaking strength observed in rats ingesting vanadate.

Fascial incisions heal faster than skin: a new model of abdominal wall repair

BACKGROUND

Optimal healing of the fascial layer is a necessary component of complete abdominal wall repair. The majority of acute wound healing studies have focused on the dermis. We designed a model of abdominal wall repair that, to our knowledge, for the first time simultaneously characterizes differences in the wound healing trajectories of the fascia and skin.

METHODS

Full-thickness dermal flaps were raised on the ventral abdominal walls of rats, and midline fascial celiotomies were completed. The dimensions of the flap were developed so as to have no detrimental effect on skin healing. The dermal flaps were replaced so that the fascial incisions would heal separately from the overlying skin incisions. Animals were killed 7, 14, and 21 days after operation and fascial and dermal wounds were harvested and tested for breaking strength. Fascial and dermal wounds were also compared histologically for inflammatory response, fibroplasia, and collagen staining.

RESULTS

Fascial wound breaking strength exceeded dermal wound breaking strength at all time points (9.16 +/- 2.17 vs 3.51 +/- 0.49 N at 7 days, P <.05). Fascial wounds also developed greater fibroblast cellularity and greater collagen staining 7 days after the incision. There was no difference in wound inflammatory response.

CONCLUSIONS

Fascial incisions regain breaking strength faster than simultaneous dermal incisions. The mechanism for this appears to involve increased fascial fibroplasia and collagen production after acute injury.

Effect of TNF gene depletion on liver regeneration after partial hepatectomy in mice

BACKGROUND

Tumor necrosis factor-alpha (TNF) is thought to act as a stimulator for initiating hepatocyte proliferation after partial hepatectomy (PH). At the same time, TNF induces a series of inflammatory responses that may be detrimental for the liver and other remote organs. The purpose of this study was to investigate the effect of TNF on the pathophysiologic state after PH.

METHODS

Wild-type (TNF+/+) and TNF-deficient (TNF-/-) mice underwent 70% PH. Hepatocyte proliferation was assessed by bromodeoxyuridine labeling and mitotic index. Liver function was evaluated by alanine aminotransferase (ALT) and total bilirubin levels in serum after PH. Myeloperoxidase activity in the liver and lung was measured as a marker for neutrophil activation.

RESULTS

No differences were observed in liver regeneration or hepatocyte proliferation between TNF+/+ and TNF-/- mice. The survival of TNF-/- mice on day 1 after PH was significantly higher than that of TNF+/+ mice, but both groups had similar survival thereafter. The ALT level was significantly higher in TNF+/+ mice 6 hours after PH and myeloperoxidase activities in both liver and lung were markedly elevated in TNF+/+ mice compared with TNF-/- mice.

CONCLUSIONS

These findings demonstrate that TNF gene-depleted mice do not demonstrate delayed liver regeneration but do suppress neutrophil activation after PH compared with results in wild-type (TNF +/+) mice.

Growth hormone does not attenuate the inhibitory effects of sepsis on wound healing

Chronic abdominal sepsis is associated with impaired tissue repair. Treatment of burn patients with growth hormone results in improved healing of skin graft donor sites. The goal of this study was to determine whether administration of growth hormone could attenuate the inhibitory effects of sepsis on cutaneous wound healing. Four groups of male Sprague Dawley rats were studied: control, control + growth hormone, sepsis, and sepsis + growth hormone. Sepsis was caused by implantation of a bacterial focus in the peritoneal cavity. Control animals underwent sham laparotomy, and polyvinyl alcohol sponge implants were placed in subdermal pockets in all animals. Saline or growth hormone (400 microg) was injected subcutaneously every 12 hours. On day 5, the incisional wounds and polyvinyl alcohol sponge implants were harvested. The breaking strength of abdominal incisions was measured. Granulation tissue penetration and quality were determined by scoring polyvinyl alcohol sponge implant histology from 1 to 4 in a blinded fashion. Collagen deposition in polyvinyl alcohol sponge implants was quantitated by hydroxyproline assay. Septic mortality was not altered by growth hormone administration. Septic animals showed a reduction in food consumption for 2 days after surgery (p < 0.05 vs. controls), which was not affected by growth hormone administration. The breaking strength of incisional wounds and hydroxyproline content of polyvinyl alcohol sponge implants was reduced in septic rats (p < 0.001 vs. controls) but administration of growth hormone for 5 days did not improve breaking strength or collagen deposition in either group. We conclude that the administration of growth hormone for 5 days did not improve collagen deposition or breaking strength in cutaneous wounds from control or septic animals. The results suggest that growth hormone treatment is unlikely to improve tissue repair in sepsis-induced catabolic illness.

Interleukin-1 receptor antagonist attenuates tumor necrosis factor-induced alterations in wound breaking strength

BACKGROUND

Tumor necrosis factor (TNF) is an important mediator of impaired wound healing during sepsis. To determine whether the inhibitory effects of systemic TNF on wound healing are mediated directly by TNF or by means of the induction of interleukin-1 (IL-1), we investigated the effects of TNF and interleukin- receptor antagonist (IL-1ra) on wound healing in healthy rats.

METHODS

Male Sprague-Dawley rats were anesthetized, and jugular catheters were placed. After recovery of 48 hours, osmotic minipumps were inserted into the peritoneal cavity and polyvinyl alcohol implants were placed subcutaneously. Control rats were infused with saline (24 microL/day, i.p., and 15 mL/day, i.v.). TNF rats received TNF i.p. (100 microg/kg per day) and saline i.v. (15 mL/day). TNF+IL-1ra rats received TNF i.p. (100 microg/kg per day) and IL-1ra i.v. (2 mg/kg per day;15 mL/day). All animals were pair fed to the TNF group. On day 6, the wounds were harvested. The breaking strength of the abdominal incision was measured. Granulation tissue penetration and quality were determined by scoring polyvinyl alcohol implant histology from 1 to 4 in a blinded manner. Collagen deposition in polyvinyl alcohol implants was quantified by hydroxyproline assay.

RESULTS

TNF decreased the breaking strength of incisional wounds to 40% of control levels (p < 0.001). IL-1ra restored the breaking strength of incisions from TNF-infused animals to 80% of control levels. Similar reductions in granulation tissue penetration, quality, and hydroxyproline content were observed in TNF-treated animals and were partially ameliorated by IL-1ra.

CONCLUSION

IL-1ra significantly attenuates the inhibitory effects of systemic TNF on wound healing. These results suggest that the inhibitory effects of TNF on cutaneous tissue repair are mediated in part by IL-1.