Cold-water treatment of scald injury and inhibition of histamine-mediated burn edema

Using the hairless mouse ear burn model we have studied the effects of immediate short-term cold-water treatment (CWT) of a moderate scald injury (54°C water for 20 sec) to intact skin using 8–10°C water for 5 min. CWT following scald injury caused brief periods of arteriolar vasomotion and shortened the duration of postburn venular dilation by about 50% as compared to untreated burns. CWT significantly (P < 0.05) reduced edema formation of the burned ear for only the first 2 hr after injury as compared to untreated burns. Significant delayed remote edema formation normally observed in abdominal and unburned (contralateral) ear skin after untreated ear scald injury was abolished after CWT to the burned ear. Chemical inhibition of remote burn edema, comparable to that achieved with CWT, was produced by cimetidine pretreatment or histamine depletion prior to injury. CWT also significantly decreased tissue histamine loss of the burned ear after scald injury Ultrastructural demonstration of increased vacuole formations in capillary and venular endothelial cells in edematous, unburned ear skin 2 hr after untreated scald injury suggested the presence of histamine-mediated remote burn edema formation. Predominant pathophysiologic mechanisms of CWT in local and remote burn edema inhibition and perhaps burn shock protection were suggested as: (1) decreased vascular response with a shortened duration of postburn venular dilation, and, most importantly, (2) the inhibition of local and systemic histamine release from thermally injured tissues.     

GHK‐Cu‐liposomes accelerate scald wound healing in mice by promoting cell proliferation and angiogenesis

Glycyl‐l ‐histidyl‐l ‐lysine (GHK)‐Cu is considered to be an activator of tissue remodeling, and has been used in cosmetic products. In this study, we prepared liposomes encapsulating GHK‐Cu and analyzed their effect on human umbilical vein endothelial cells (HUVECs) proliferation and scald wound healing in mice. The nanoscaled GHK‐Cu‐liposomes promoted HUVECs proliferation, with a 33.1% increased rate. Flow cytometry analysis showed increased cell number at G1 stage and decreased cell number at G2 stage after GHK‐Cu‐liposomes treatment. Western blotting indicated that the expression of vascular endothelial growth factor and fibroblast grow factors‐2 were both enhanced, as well as cell cycle‐related proteins CDK4 and CyclinD1. In a mice scald model, angiogenesis in burned skin treated with GHK‐Cu‐liposomes was better compared with free GHK‐Cu, and immunofluorescence analysis showed enhanced signal of CD31 and Ki67 in GHK‐Cu‐liposomes treated mice. Moreover, the wound healing time was shortened to 14 days post injury. Our results provide the evidence that GHK‐Cu‐liposomes could be utilized as a treatment for skin wounds.     

Exogenous metallothionein‐IIA promotes accelerated healing after a burn wound

Severe injury to the epidermal barrier often results in scarring and life‐long functional deficits, the outcome worsening with a number of factors including time taken to heal. We have investigated the potential of exogenous metallothionein IIA (Zn₇‐MT‐IIA), a naturally occurring small cysteine‐rich protein, to accelerate healing of burn wounds in a mouse model. Endogenous MT‐I/II expression increased in basal keratinocytes concurrent with reepithelialization after a burn injury, indicating a role for MT‐I/II in wound healing. In vitro assays of a human keratinocyte cell line indicated that, compared with saline controls, exogenous Zn₇‐MT‐IIA significantly increased cell viability by up to 30% (p<0.05), decreased apoptosis by 13% (p<0.05) and promoted keratinocyte migration by up to 14% (p<0.05), all properties that may be desirable to promote rapid wound repair. Further in vitro assays using immortalized and primary fibroblasts indicated that Zn7‐MT‐IIA did not affect fibroblast motility or contraction (p>0.05). Topical administration of exogenous Zn₇‐MT‐IIA (2 μg/mL) in vivo, immediately postburn accelerated healing, promoted faster reepithelialization (3 days: phosphate‐buffered saline (PBS), 8.9±0.3 mm diameter vs. MT‐I/II, 7.1±0.7 mm; 7 days: PBS 5.8±0.98 mm vs. MT‐I/II, 3.6±1.0 mm, p<0.05) and reduced epidermal thickness (MT‐I/II: 45±4 μm vs. PBS: 101±19 μm, p<0.05) compared with controls. Our data suggest that exogenous Zn₇‐MT‐IIA may prove a valuable therapeutic for patients with burns and other skin injuries.     

Basic fibroblast growth factor accelerates and improves second‐degree burn wound healing

Second‐degree burns are sometimes a concern for shortening patient suffering time as well as the therapeutic choice. Thus, adult second‐degree burn patients (average 57.8 ± 13.9 years old), mainly with deep dermal burns, were included. Patients receiving topical basic fibroblast growth factor (bFGF) or no bFGF were compared for clinical scar extent, passive scar hardness and elasticity using a Cutometer, direct scar hardness using a durometer, and moisture analysis of the stratum corneum at 1 year after complete wound healing. There was significantly faster wound healing with bFGF, as early as 2.2 ± 0.9 days from the burn injury, compared with non‐bFGF use (12.0 ± 2.2 vs. 15.0 ± 2.7 days, p<0.01). Clinical evaluation of Vancouver scale scores showed significant differences between bFGF‐treated and non‐bFGF–treated scars (p<0.01). Both maximal scar extension and the ratio of scar retraction to maximal scar extension, elasticity, by Cutometer were significantly greater in bFGF‐treated scars than non‐bFGF–treated scars (0.23 ± 0.10 vs. 0.14 ± 0.06 mm, 0.59 ± 0.20 vs. 0.49 ± 0.15 mm: scar extension, scar elasticity, bFGF vs. non‐bFGF, p<0.01). The durometer reading was significantly lower in bFGF‐treated scars than in non‐bFGF–treated scars (16.2 ± 3.8 vs. 29.3 ± 5.1, p<0.01). Transepidermal water loss, water content, and corneal thickness were significantly less in bFGF‐treated than in non‐bFGF–treated scars (p<0.01).     

Fibrin‐based stem cell containing scaffold improves the dynamics of burn wound healing

For severe burn injuries, successful medical intervention is accomplished by rapidly and safely providing physical barriers that can cover damaged skin tissues, thereby preventing critical danger of extensive bleeding and infection. Despite availability of a large assortment of wound coverage options, the etiology of wound healing is rather complex leading to significant defects in skin repair. The use of cell‐mediated treatment approaches in combination with bioengineered wound coverage constructs may provide the missing tool to improve wound healing outcomes. In this study, we have used an engineered 3D PEGylated fibrin (P‐fibrin) gel as a scaffold for adipose derived stem cells (ASCs) delivery into the burn injury model. We were able to confirm the presence of ASCs in the wound site two weeks after the initial injury. Delivery of ASCs‐containing gels was associated with improved vascularization of the injured area at early time points accompanied by an increased abundance of mannose receptor expressing cells. Moreover, the application of P‐fibrin biomaterial exhibited positive effects on early mononuclear cell recruitment and granulation tissue formation without negatively affecting wound closure kinetics or extent of connective tissue deposition. Collectively, our data support the feasibility of using P‐fibrin gels in wound dressing applications requiring controlled delivery of viable cells.     

Prevalence of Bovine Tuberculosis in Egyptian Cattle and the Standardization of the Interferon‐gamma Assay as an Ancillary Test

Bovine tuberculosis (bTB) caused primarily by Mycobacterium bovis continues to cause significant losses in the cattle industry and is a major public health problem. Despite its worldwide application, the IFN‐γ assay has not been applied in Egypt. The aim of this study was to determine the appropriate cut‐off value of IFN‐γ assay to complement the skin test screening in Egypt. The relative sensitivity (Se_r) of PPD and antigen cocktail‐based IFN‐γ assays (IFN‐γ‐BA and IFN‐γ‐EC) was analysed retrospectively, relative to bTB confirmatory tests (culture and PCR), using single cervical tuberculin (SCT) test reactors during 2011–2013. The absolute specificity (Sp) was studied using blood samples collected from cattle from one bTB‐free herd. Analysis of the bTB database‐generated sheets indicates the infection rate had decreased from 2009 to 2012 and then increased in 2013. The disease is concentrated in the Egyptian Nile Delta and Valley relative to elsewhere in the country. The cut‐offs for IFN‐γ‐EC assay could be optimized to provide higher sensitivity, comparable to cut‐offs for IFN‐γ‐BA assay. Data analysis suggests (PPDb_OD > 0.1, PPDb_OD − NIL_OD > 0.05 and PPDb_OD > PPDa_OD) and (EC_OD − NIL_OD ≥ 0.1) cut‐off strategies to get optimal IFN‐γ‐BA and IFN‐γ‐EC assays results respectively. To our knowledge, this is the first report describing the prevalence of bTB in cattle in Egypt and pointing out the appropriate cut‐off criteria to optimize IFN‐γ assay as a routine ancillary test for diagnosis of bTB in Egypt.     

Investigation of the skin repair and healing mechanism of N‐carboxymethyl chitosan in second‐degree burn wounds

N‐carboxymethyl chitosan (NCMC) was synthesized with the modification of chitosan; the substitution degree was measured by titration. The biocompatibility and degradability of the NCMC were studied in vivo and the results showed that the NCMC was nontoxic and biocompatible. The in vivo degradation rate of NCMC in musculature was faster than that in subcutaneous tissue due to the relatively high lysozyme concentration. The NCMC was used as biomaterial to heal deep second‐degree burn wounds. The wound size reduction, histological examination, and the quantification of transforming growth factor‐β₁, tumor necrosis factor‐α and interleukin‐8 protein levels, and Smad3 gene expression were measured to evaluate the healing effects. The results demonstrated that the NCMC was efficient in accelerating wound healing via activating transforming growth factor‐β₁/Smad3 signaling pathway.     

Deep dermal burn injury results in scarless wound healing in the ovine fetus

Early to mid-term fetuses heal cutaneous incisional wounds without scars; however, fetal response to burn injury has not been ascertained. We present a fetal model of thermal injury and subsequent analysis of fetal and lamb response to burn injury. A reproducible deep dermal burn injury was created in the fetus by application of water at 66 degrees C for 7 seconds, and at 82 degrees C for 10 seconds to the lamb. Macroscopically, the area of fetal scald was undetectable from day 7 post injury, while all lamb scalds were readily identified and eventually healed with scarring. Using a five-point histopathology scoring system for alteration in tissue morphology, differences were detected between control and scalded skin at all stages in lamb postburn, but no difference was detected in the fetal model after day 7. There were also large differences in content of alpha-smooth muscle actin and transforming growth factor-beta1 between control and scalded lamb and these differences were statistically significant at day 14 (P < 0.01). This novel model of fetal and lamb response to deep dermal injury indicates that the fetus heals a deep burn injury in a scarless fashion. Further elucidation of this specific fetal process of burn injury repair may lead to improved outcome for patients with burn injury.     

An investigation of the role of diet and burn injury on wound healing

Forty-four rats underwent standard laparotomies and were randomly allocated to four groups according to injury (control or burned) and diet (maintenance or protein depleted). Wound healing was assessed tensiometrically on the 14th postoperative day. The energy intakes of the four groups were comparable. Both injury by burning and protein depletion caused significant weight loss. The peak force applied to the laparotomy wounds was unaltered by burning, but protein depletion caused a significant reduction in wound strength. It is concluded that any impairment in wound healing in burned patients is more likely to result from inadequate feeding rather than the injury itself or any resultant weight loss.     

成纤维细胞生长因子促进放烧复合伤创面愈合的实验研究

采用重组的碱性成纤维细胞生长因子(bFGF),观察其对大鼠重度放烧复合伤皮肤创面愈合的作用。结果提示:bFGF治疗组第60天创面完全愈合的百分率较对照组提高28.5％,50％烧伤面积愈合所需的平均时间较对照组提前9天。病理学检查发现,bFGF可刺激成纤维细胞增殖及胶原合成,促进毛细血管增生和肉芽组织形成。在早期,bFGF尚可增强创面炎症反应,提高机体白细胞吞噬功能,加速脾细胞NK活性的恢复。     

Triptolide inhibits donor‐specific antibody production and attenuates mixed antibody‐mediated renal allograft injury

Donor‐specific antibodies (DSAs) are major mediators of renal allograft injury, and strategies to inhibit DSAs are important in promoting long‐term graft survival. Triptolide exhibits a wide spectrum of antiinflammatory and immunosuppressive activities, and in autoimmune diseases it inhibits autoantibody levels. In this study, we investigated the suppressive role of triptolide in the generation of DSAs in transplant recipients. We found that triptolide treatment of skin allograft recipients in mice significantly suppressed the development of circulating anti‐donor‐specific IgG and effectively alleviated DSA‐mediated renal allograft injury, which led to prolonged allograft survival. In vitro studies revealed that triptolide inhibited the differentiation of B cells into CD138⁺CD27⁺⁺ plasma cells; reduced the levels of IgA, IgG, and IgM secreted by plasma cells; and repressed somatic hypermutation and class switch recombination of B cells. Moreover, triptolide‐treated recipients showed reduced numbers of B cells, plasma cells, and memory B cells in spleens and decreased numbers of T, B, natural killer (NK) cells, and macrophages infiltrating grafts. These findings highlight the importance of triptolide in suppressing DSAs and establish triptolide as a novel therapeutic agent for antibody‐mediated allograft rejection.     

Blood vessel occlusion in peri‐burn tissue is secondary to erythrocyte aggregation and mitigated by a fibronectin‐derived peptide that limits burn injury progression

Although vascular occlusion has long been noted in peri‐burn tissue, the literature is inconsistent regarding the nature of the occlusion, with articles in the 1940s claiming that erythrocytes were the culprit and in the 1980s–1990s that microthrombi were responsible. To better define the nature of vessel occlusion, we studied two porcine burn models, a hot comb horizontal injury model and a vertical injury progression model. In both cases, tissue from the first two days after burn were stained with hemotoxylin and eosin, or probed for platelets or for fibrinogen/fibrin. Erythrocytes, identified as nonstained, clumped, anuclear, 5 µm cells, occluded most blood vessels (BVs) in both burn models. In contrast, platelet or fibrinogen/fibrin antibodies stained BV occlusions minimally at early time points, and only up to 16% of deep dermal BVs at 48 hours in the hot comb model and up to 7% at 24 hours in the vertical injury progression model. Treatment of animals with a fibronectin‐derived peptide (P12), which limits burn injury progression and can dilate peripheral microvasculature, reduced erythrocyte occlusion by at least 50%, speeded healing and reduced scarring. Early erythrocyte aggregation, rather than thrombosis, explains the ineffectiveness of anticoagulants to prevent burn injury progression.     

Necrostatin‐1 inhibits Hmgb1‐IL‐23/IL‐17 pathway and attenuates cardiac ischemia reperfusion injury

Ischemia reperfusion (IR) injury is a major issue in cardiac transplantation and inflammatory processes play a major role in myocardial IR injury. Necrostatin‐1 (Nec‐1) is a small molecule capable of inhibiting RIP1 kinase activity and attenuates inflammation‐mediated tissue injury. In our study, hearts of C57Bl/6 mice were flushed and stored in cold Bretschneider solution for 8 h and then transplanted into syngeneic recipients. We found that Nec‐1 decreased cardiomyocyte necrosis and recruitment of neutrophils and macrophages. Troponin T (TnT) production on 24 h after myocardial IR injury was reduced by Nec‐1 administration. Cardiac output at 60 mmHg of afterload pressure was significantly increased in hearts with Nec‐1 administration and the cardiac allograft survival in Nec‐1‐treated animals was significantly prolonged (MST = 90 days in IR + Nec‐1 group, P < 0.05 as compared with IR group, MST = 83.5 days). Nec‐1 treatment attenuated ROS generation and increased expression of NOS2 and COX‐2. The expression of Hmgb1, IL‐23, and IL‐17A were also decreased with Nec‐1 administration. Furthermore, the decreased TnT expression induced by Nec‐1 was abrogated with exogenous Hmgb1 administration. In conclusion, Nec‐1 played a protective role in cardiomyocyte IR injury, and this was associated with inhibited Hmgb1‐IL‐23/IL‐17 pathway.     

Interferon‐free antiviral treatment of chronic hepatitis C in the transplant setting

Interferon‐based regimens with first‐generation protease inhibitors have a limited efficacy and an unfavorable safety profile. Combination therapies with two or more second‐generation direct‐acting antivirals plus/minus ribavirin revolutionized treatment strategies in patients chronically infected with hepatitis C virus. In this rapidly evolving era, patients in the transplant setting benefit from interferon‐free treatment regimens. Scientific societies can barely keep up with this development, making it necessary to update the clinical guidelines by the American and European Associations for the Study of Liver Diseases within short periods. This review presents and discusses the currently available data of the use of interferon‐free treatment in the setting of liver transplantation. However, costs, different reimbursement strategies, and health‐care options cannot be answered by guidelines and recommendations from scientific societies. Further investigator‐initiated trials are needed to individualize treatment concepts.     

Evidence‐based injury prediction data for the water temperature and duration of exposure for clinically relevant deep dermal scald injuries

Deep dermal burn injuries require extensive medical care; however, the water temperatures and durations of exposure that result in a severe scald injury are unknown. This study used a porcine burn model to investigate the time and temperature threshold for clinically relevant deep dermal injuries for both immersion (long duration) and spill/splash (short duration) scald events. Scald wounds were created on the flanks of anaesthetized juvenile large White pigs (27 kg). Acute tissue injury evaluations performed at 1 hour and days 1, 3, and 7 postburn (16 pigs) included: wound examination, biopsies, and laser Doppler imaging. Up to 20 burn combinations were tested including: 50–60 °C water for 1–10 minutes (immersion); and 60–90 °C water for 5 seconds (spill/splash). Burn conditions demonstrating mid‐to‐deep dermal damage histologically were followed for 21 days to assess time to reepithelialize (eight pigs). Histologically, depth of damage increased until day 3 postburn. Damage to ≥75% of the depth of dermis was associated with burns taking longer than 3 weeks to fully reepithelialize. For spill/splash (5 seconds) scalds, water at ≥75 °C showed damage to mid‐dermis or deeper by day 3; however, only burns from water ≥85 °C were not reepithelialized by day 21. For immersion scalds of equivalent duration, water at 55 °C caused significantly deeper dermal damage than 50 °C (p < 0.05) at day 3. Immersion scalds that were not fully reepithelialized by day 21 included 50 °C for >10 minutes, 55 °C for 5 minutes, 60 °C for 60 seconds, and 70 °C for > 15 seconds. This research provides valuable evidence‐based injury prediction data, which can be used to inform future burn injury prevention guidelines/legislation to reduce the risk of severe scald injuries and support medicolegal opinions for cases where an inflicted mechanism of injury is alleged.     

Cutaneous microcirculatory assessment of the burn wound is associated with depth of injury and predicts healing time

Rationale

Current trends for the treatment of deep partial thickness and full-thickness burns include early excision and skin grafting. In this study we retrospectively evaluated the ability of Laser Doppler Flowmetry (LDF), taken within 24 h of the burn to predict: (1) burn wound depth and (2) wounds which would heal in less than 21 days.

Method

The Laser Doppler Flowmeter (O2C, LEA Medizintechnik, Germany) was employed to non-invasively measure the cutaneous microcirculation of 173 selected areas on 28 patients who suffered burns.

Results

A distinct association between initial flow (<24 h after burn injury) and the clinical assessment of depth of burn wounds was observed. Wounds demonstrating an initial blood flow of >100 AU were, in 93.1% of cases, correctly (positively) predicted for spontaneous healing within 21 days. A blood flow of <100 AU (negatively) predicted in 88.2%, those wounds which would not go on to heal within 21 days. Sequential measurement analysis (<24 h, 3 days after injury and 6 days after injury) revealed no significant decrease in skin perfusion velocity or flow rate.

Conclusion

LDF can provide immediate results for early determination of burn wound depth and is useful in selecting patients for conservative treatment of their burn wounds.