Cytotoxicity, Epidermal Barrier Function and Cytokine Evaluation after Antiseptic Treatment in Bioengineered Autologous Skin Substitute

Antibiotic biocompatibility assay and anti-biofilm strategies for Pseudomonas aeruginosa infection in bioengineered artificial skin substitutes

OBJECTIVES

Bioengineered artificial skin substitutes (BASS) are an advanced therapy for treating extensively burned patients. Pseudomonas aeruginosa (P. aeruginosa) infections represent a major challenge in these patients as formation of biofilms impede wound healing and perpetuate a chronic inflammatory state. Here we assessed antibiotics (alone or in combination) with respect to cytotoxicity, as well as antimicrobial efficacy in P. aeruginosa biofilm formed on infection of BASS.

METHODS

Cell viability, structure and functionality were evaluated using microscopy and trans-epidermal water loss analyses, respectively. BASS were established and infected for 24 h to allow P. aeruginosa biofilm formation, after which two antimicrobial approaches, treatment and prevention, were tested. In the latter, antibiotics were added to BASS before infection. The antimicrobial effect was determined using real-time calorimetry.

RESULTS

In dose-response experiments, 1.25 mg/mL amikacin, 0.02 mg/mL ciprofloxacin, 0.051 mg/mL colistin, 1 mg/mL meropenem and colistin in combination with either amikacin, ciprofloxacin and meropenem did not affect BASS' viability, structure and functionality. All antibiotics, except colistin, showed effective antimicrobial activity at these non-cytotoxic concentrations. For concentrations below the highest non-cytotoxic ones, successive treatments resulted in higher bacterial metabolic rates. Only the combinations managed to eradicate the infection with repeated treatments. With respect to prevention of infection, all antibiotics at the highest non-cytotoxic concentrations and the combinations were effective. This preventive capacity was maintained for at least 5 days.

CONCLUSION

The findings highlight the potential for developing BASS with antimicrobial properties that can prevent infections during wound healing in burn patients.

Radiation-induced skin injury in the head and neck region: pathogenesis, clinics, prevention, treatment considerations and proposal for management algorithm

Worldwide increase of head and neck cancers ranks these malignancies among top causes of cancer in human population. Radiation induced skin injury (RISI) is one of the major side effects of radiotherapy (RT). Skin of the neck is exposed to radiation due to necessity of therapeutic or prophylactic (elective) irradiation of neck lymph nodes and target organs, including the larynx and hypopharynx. The location of the neck exposes these regions of the skin to various additional exposomes such as ultraviolet radiation (UVR), pollution and cigarette smoke. There are many controversies or inconsistencies regarding RISI, from molecular aspects and therapy to terminology. There is lack of high-quality and large-sample studies in both forms of RISI: acute (aRISI) and chronic (cRISI). Finally, no gold standards in the management of aRISI and cRISI have been established yet. In this article, the authors discuss the pathogenesis, clinical picture, prevention and clinical interventions and present a proposed treatment algorithm.

The Tissue Engineering Revolution: From Bench Research to Clinical Reality

At its core, tissue engineering involves the use of a scaffold for the formation of new viable tissue for medical purposes [...].

Antibiotics against Pseudomonas aeruginosa on Human Skin Cell Lines: Determination of the Highest Non-Cytotoxic Concentrations with Antibiofilm Capacity for Wound Healing Strategies

Pseudomonas aeruginosa is one of the most common microorganisms causing infections of severe skin wounds. Antibiotic or antiseptic treatments are crucial to prevent and curb these infections. Antiseptics have been reported to be cytotoxic to skin cells and few studies evaluate the impact of commonly used antibiotics. This study evaluates how clinical antibiotics affect skin cells' viability, proliferation, migration, and cytokine secretion and defines the highest non-cytotoxic concentrations that maintain antibacterial activity. Cell proliferation, viability, and migration were evaluated on cell monolayers. Cytokines related to the wound healing process were determined. The minimum inhibitory concentrations and the impact on bacterial biofilm were assessed. Results showed that 0.02 mg/mL ciprofloxacin and 1 mg/mL meropenem are the highest non-cytotoxic concentrations for fibroblasts and keratinocytes while 1.25 mg/mL amikacin and 0.034 mg/mL colistin do not affect fibroblasts' viability and cytokine secretion but have an impact on keratinocytes. These concentrations are above the minimum inhibitory concentration but only amikacin could eradicate the biofilm. For the other antibiotics, cytotoxic concentrations are needed to eradicate the biofilm. Combinations with colistin at non-cytotoxic concentrations effectively eliminate the biofilm. These results provide information about the concentrations required when administering topical antibiotic treatments on skin lesions, and how these antibiotics affect wound management therapies. This study set the basis for the development of novel antibacterial wound healing strategies such as antibiotic artificial skin substitutes.