Abstract


Introduction: The aim of this study was to evaluate if a poloxamer-based concentrated surfactant gel (CSG), containing antibacterial preservative agents, had the ability to reduce the levels of biofilm extracellular polymeric substances (EPS), specifically proteins and extracellular DNA (eDNA), as these are found to be the most immunogenic, within an in vitro biofilm.
Materials and Methods: A 24-hour biofilm of P. aeruginosa ATCC 15442 was grown in a 12-well plate and treated for 24 hours with a CSG coated onto Multisorb® (BSN Medical Limited, Hull, United Kingdom). EPS were extracted from each sample using 1M sodium chloride. Protein and DNA in EPS extractions was determined quantitatively using the Pierce™ Coomassie (Bradford) protein assay kit and a microplate SYTO 9™ (ThermoFisher Scientific, Paisley, United Kingdom) fluorescent assay, respectively. Protein and DNA was also determined qualitatively using confocal laser scanning microscopy (CLSM).
Results: Following 24-hour growth of P. aeruginosa ATCC 15442 biofilm, 7.38mg/mL protein was isolated from the extracted EPS in the untreated control. In comparison, the protein concentration found in the extracted EPS from biofilms treated with a CSG was 6.39mg/mL, showing a 13.4% reduction. Following 24-hour growth of P. aeruginosa ATCC 15442 biofilm, 11.71mg/mL eDNA was isolated from the extracted EPS in the untreated control. In comparison, the eDNA concentration found in the extracted EPS from biofilms treated with a CSG was 0.65mg/mL, showing a 94.5% reduction. Following statistical analysis of the data, the decrease in protein isolated following CSG treatment was within error; however, the decrease in eDNA isolated was statistically significant, showing the ability of the CSG to break up biofilm EPS in vitro. Using confocal laser microscopy and staining techniques, a large quantity of protein and eDNA could be observed in samples from the untreated control. In comparison, a reduction in EPS protein and eDNA was observed in samples that had been treated with a CSG.
Conclusion: The data presented here potentially shows the ability of a CSG to reduce components of the P. aeruginosa biofilm EPS. The reduction in eDNA following CSG treatment may contribute to the dispersal of the biofilm, potentially increasing the susceptibility of it to antimicrobials, and should be explored further.

Abstract


The surgical surgical debridement of wounds has evolved over the past 250 years. At that time, the amputation of extremities was recognized as a life-saving procedure to treat major wounds suffered in combat. This continued until after World War I. As the survival of patients with diabetes and other chronic conditions improved, and as advanced therapies were developed to meet the needs of an increasing number of patients with chronic wounds, debridement became a focal point of surgical wound care. It is now well-established that debridement enhances wound-healing and improves the efficacy of advanced therapies and surgical closure. Up until the last two decades, sharp excision with “cold steel” was the only option for debridement. In the early 2000’s, a high-power waterjet was introduced, and provided a more precise debridement of wound surfaces. As our understanding of biofilms increased, so came the realization that biofilms are stratified within the wound, with anaerobic species preferentially developing deeper within the wound. The latest surgical instrument for wound debridement, the direct contact low frequency ultrasound device (DCLFU), has recently been introduced. A vacuum sheath was added to the active tip to contain spray dispersion. The device is capable of removing all of the wound tissue including biofilm down to a healthy base. This allows for optimal preparation of the wound prior to deployment of an advanced therapy, graft, or flap. This instrumentation is designed specifically for use in the operating room. However, the manufacturer has recently introduced a less powerful, but still effective, version for use in the outpatient clinic. These advances in surgical debridement technology have paved the way for more effective subsequent interventions for treating chronic wounds.

Abstract


Skeletal muscle represents the largest mass of tissue in the body and is essential for motion and posture. Traumatic injury, tumor ablation, prolonged denervation or genetic defects lead to skeletal myopathies. The loss of muscle function or its regenerative properties often results in pain, deformity, and joint malfunction. The regenerative capacity of skeletal muscles depends on adult muscle stem cells, the so-called satellite cells; however, the population of these myogenic precursors, and thus their potential to restore large muscle tissue defects, is strongly limited. On the other hand, surgical treatment of skeletal muscle loss is hampered by the scarcity of functional replacement tissue. Only a few options currently exist to provide functional and aesthetic restoration of lost muscle tissues, other than free muscle flap transfer. While this reconstructive technique is a common practice, it involves the risk of significant donor-site morbidity. Therefore, alternative cells with the potential to regenerate muscle tissue need to be examined. Recently, many surgeons have studied the potential clinical application of mesenchymal stem cells (MSCs), which are an adult stem cell population that can undergo differentiation along the mesodermal lineage and secrete growth factors that can enhance tissue regeneration processes by promoting neovascularization. The regenerative potential of MSCs has been widely studied in vitro and in vivo in animal models. MSCs from adipose tissue as well as bone marrow have been shown to bear myogenic potential, which makes them ideal candidate stem cells for skeletal muscle tissue engineering applications. When compared to reconstructive procedures using autograft tissues, MSC therapy offers the potential of reducing or even eliminating donor-site morbidity. This review gives a comprehensive overview of the use of MSCs in in vitro muscle generation and in vivo muscle regeneration.