Randomized placebo‐controlled human pilot study of cold atmospheric argon plasma on skin graft donor sites

Cold atmospheric plasma has already been shown to decrease the bacterial load in chronic wounds. However, until now it is not yet known if plasma treatment can also improve wound healing. We aimed to assess the impact of cold atmospheric argon plasma on the process of donor site healing. Forty patients with skin graft donor sites on the upper leg were enrolled in our study. The wound sites were divided into two equally sized areas that were randomly assigned to receive either plasma treatment or placebo (argon gas) for 2 minutes. Donor site healing was evaluated independently by two blinded dermatologists, who compared the wound areas with regard to reepithelialization, blood crusts, fibrin layers, and wound surroundings. From the second treatment day onwards, donor site wound areas treated with plasma (n = 34) showed significantly improved healing compared with placebo‐treated areas (day 1, p = 0.25; day 2, p = 0.011; day 3, p < 0.001; day 4, p < 0.001; day 5, p = 0.004; day 6, p = 0.008; day 7, p = 0.031). Positive effects were observed in terms of improved reepithelialization and fewer fibrin layers and blood crusts, whereas wound surroundings were always normal, independent of the type of treatment. Wound infection did not occur in any of the patients, and no relevant side effects were observed. Both types of treatment were well tolerated. The mechanisms contributing to these clinically observed effects should be further investigated.     

The comparison of two negative‐pressure wound therapy systems in a porcine model of wound healing

The purpose of this study was to compare two negative‐pressure wound healing systems (NPWT), ?75 mmHg with a silicone‐coated (SC) dressing and ?125 mmHg with polyurethane foam dressing (standard of care). In addition, this study compared the effects of two different dressing interfaces, SC dressing and gauze, with ?75 mmHg pressure. For both comparisons, two groups of five pigs were evaluated over a 21‐day time course. Two excisional wounds were made on each animal and NPWT dressings were applied. A canvas saddle was constructed to hold the NPWT device so the animal had free range of the pen. Dressings were changed twice a week and wound measurements were taken. Specimens for histology and gene expression analyses were taken on day 7 and 21. These data show that there is increased expression in a few genes associated with remodeling and inflammatory processes in the NPWT‐125 with polyurethane foam as compared with the NPWT‐75 with SC dressing. These two systems, however, are equivalent with respect to wound healing, histology, and gene expression over 21 days of healing. Further, we demonstrate that there is no difference in measure of healing between the SC dressing and a basic gauze dressing.     

Adipose tissue‐derived stem cells (ADSCs) transplantation promotes regeneration of expanded skin using a tissue expansion model

Transplantation of adipose tissue‐derived stem cells (ADSCs) is a promising method that has been used in regenerative medicine because it has shown the capacity to accelerate wound healing. However, roles of ADSCs transplantation in expanded‐skin regeneration have remained unknown. To clarify the roles, a tissue expansion model was used in this study. The study comprised three groups of 13 rats in each group: the ADSCs group, the fibroblast (FB) group, and the control group. The skin regeneration in the ADSCs group was enhanced, as evidenced by increased cell proliferation and a higher hydroxyproline content and degree of neovascularization, all with p < 0.05, when compared with both the FB group and the control group. Consistent with enhanced cell proliferation and neovascularization, the regenerated skin in the ADSCs group was much thicker, which further reduced the retraction ratio of the expanded skin. Four weeks after operation, 5'‐bromo‐2'‐deoxyuridine‐labeled ADSCs appeared in subcutaneous tissue, vascular vessels, and hair follicles. The up‐regulation of protein expression, such as epidermal growth factor and vascular endothelial growth factor, primarily emerged in the ADSC group, with the up‐regulated basic fibroblast growth factor appearing in the FB group. Collectively, these results suggest that the transplantation of ADSCs could enhance the regeneration of expanded skin by participating in skin structures and up‐regulating the secretion of epidermal growth factor and vascular endothelial growth factor.     

Therapeutic option for managing lung injury induced by infrarenal aortic cross-clamping

Background

Operations on the infrarenal aorta can cause ischemic-reperfusion (IR) injury in local tissues, which could result in remote organ (e.g., lung) damage. Treatment of such injuries remains an unresolved problem.

Objectives

Our aim was to reduce remote lung damage after lower limb IR by means of postconditioning.

Materials and methods

Male Wistar rats were divided into three groups: Sham-operated, IR, and Postconditioned (PostC). In the latter two groups rats underwent 180 min of exclusion of the infrarenal aorta. The reperfusion time was 4 h. Serum-free radical levels, tumor necrosis factor-α and interleukin-6 concentrations, histologic changes in the lung, wet/dry-ratio, myeloperoxidase activity, heat shock protein 72 level and blood gas changes were investigated.

Results

Postconditioning reduced histological damage in the lung (P < 0.05). Free radical levels and tumor necrosis factor-α concentrations were significantly lower in the PostC group than in the IR group (P < 0.05 and P < 0.01, respectively). Interleukin-6 concentrations did not significantly differ in the PostC group. Compared with the IR group, lung myeloperoxidase activity was lower in the PostC group. Decreased pulmonary heat shock protein 72 level was observed in the PostC group compared with the IR group and the wet/dry-ratio was also significantly lower in the PostC group (P < 0.05). A noticeably higher arterial pO₂ level was manifest in the PostC group after 2 and 4 h of reperfusion (P < 0.05).

Conclusions

Postconditioning reduced lung damage under experimental conditions, in the early period of reperfusion after lower limb IR injury.