Radiosterilized Pig Skin, Silver Nanoparticles and Skin Cells as an Integral Dressing Treatment for Burns: Development, Pre-Clinical and Clinical Pilot Study.

Radiosterilized pig skin (RPS) has been used as a dressing for burns since the 1980s. Its similarity to human skin in terms of the extracellular matrix (ECM) allows the attachment of mesenchymal stem cells, making it ideal as a scaffold to create cellularized constructs. The use of silver nanoparticles (AgNPs) has been proven to be an appropriate alternative to the use of antibiotics and a potential solution against multidrug-resistant bacteria. RPS can be impregnated with AgNPs to develop nanomaterials capable of preventing wound infections. The main goal of this study was to assess the use of RPS as a scaffold for autologous fibroblasts (Fb), keratinocytes (Kc), and mesenchymal stem cells (MSC) in the treatment of second-degree burns (SDB). Additionally, independent RPS samples were impregnated with AgNPs to enhance their properties and further develop an antibacterial dressing that was initially tested using a burn mouse model. This protocol was approved by the Research and Ethics Committee of the INRLGII (INR 20/19 AC). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis of the synthesized AgNPs showed an average size of 10 nm and rounded morphology. Minimum inhibitory concentrations (MIC) and Kirby-Bauer assays indicated that AgNPs (in solution at a concentration of 125 ppm) exhibit antimicrobial activity against the planktonic form of S. aureus isolated from burned patients; moreover, a log reduction of 1.74 ± 0.24 was achieved against biofilm formation. The nanomaterial developed with RPS impregnated with AgNPs solution at 125 ppm (RPS-AgNPs125) facilitated wound healing in a burn mouse model and enhanced extracellular matrix (ECM) deposition, as analyzed by Masson's staining in histological samples. No silver was detected by energy-dispersive X-ray spectroscopy (EDS) in the skin, and neither by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in different organs of the mouse burn model. Calcein/ethidium homodimer (EthD-1), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and scanning electron microscopy (SEM) analysis demonstrated that Fb, Kc, and MSC could attach to RPS with over 95% cell viability. Kc were capable of releasing FGF at 0.5 pg above control levels, as analyzed by ELISA assays. An autologous RPS-Fb-Kc construct was implanted in a patient with SDB and compared to an autologous skin graft. The patient recovery was assessed seven days post-implantation, and the patient was followed up at one, two, and three months after the implantation, exhibiting favorable recovery compared to the gold standard, as measured by the cutometer. In conclusion, RPS effectively can be used as a scaffold for the culture of Fb, Kc, and MSC, facilitating the development of a cellularized construct that enhances wound healing in burn patients.

Effects of mesenchymal stem cell culture on radio sterilized human amnion or radio sterilized pig skin in burn wound healing.

Deep second and third degree burns treatment requires fibroblasts, keratinocytes and other skin cells in order to grow new dermis and epidermis. Cells can proliferate, secrete growth factors and extracellular matrix required to repair the damaged tissue. Radiosterilized human amnion and radiosterilized pig skin have been used as natural origin skin dressings for burned patients. Adipose-derived mesenchymal stem cells can differentiate into fibroblasts and keratinocytes and improve wound-healing progress. These cells can stimulate vascular tissue formation, release growth factors, synthetize new extracellular matrix and immunoregulate other cells. In this study, we developed mesenchymal stem cells-cellularized skin substitutes based from radiosterilized human amnion or pig skin. Third-degree burns were induced in mice animal models to evaluate the effect of cellularized skin substitutes on burn wound healing. Mesenchymal phenotype was immunophenotypically confirmed by flow cytometry and cell viability was close to 100%. Skin recovery was evaluated in burned mice after seven and fourteen days post-coverage with cellularized and non-cellularized sustitutes. Histological techniques and immunofluorescence were used to evaluate re-epithelization and type I collagen deposition. We determined that cellularized-human amnion or cellularized-pig skin in combination with mesenchymal stem cells improve extracellular matrix deposition. Both cellularized constructs increase detection of type I collagen in newly formed mouse skin and can be potentially used as skin coverage for further clinical treatment of burned patients.

Evaluation of copaiba oil as enhancer of ibuprofen skin permeation

Abstract The administration of medications on the skin through transcutaneous routes is a practice that has been used by mankind for millennia. Some studies have been reporting the use of terpenes and natural oils rich in terpenes as an enhancer of cutaneous penetration. Copaiba oil, due to its rich content of terpenes, presents itself as a great choice of penetration enhancer for drugs administered on the skin. In this study, we developed two cream formulations containing 5% of ibuprofen (IBU) and copaiba oil: IBCO5 and IBCO10 with 5% and 10% of copaiba oil respectively. Ex vivo cutaneous penetration/permeation studies of IBU were performed using pig ear skin as biological membrane in the Franz-type diffusion cells. The steady-state flux of IBU samples, IBCO5 (35.72 ± 6.35) and IBCO10 (29.78 ± 2.41) were significantly higher when compared with control without copaiba oil (10.32 ±1.52) and with a commercial product (14.44 ± 2.39). In the penetration analysis, the amount of IBU found in the samples IBCO5 and IBCO10 was markedly higher in the dermis than epidermis. Our results showed that copaiba oil possesses attracting properties in promoting skin penetration and permeation of IBU when added into cream formulations.

Silver-pig skin nanocomposites and mesenchymal stem cells: suitable antibiofilm cellular dressings for wound healing.

BACKGROUND: Treatment of severe or chronic skin wounds is an important challenge facing medicine and a significant health care burden. Proper wound healing is often affected by bacterial infection; where biofilm formation is one of the main risks and particularly problematic because it confers protection to microorganisms against antibiotics. One avenue to prevent bacterial colonization of wounds is the use of silver nanoparticles (AgNPs); which have proved to be effective against non-multidrug-resistant and multidrug-resistant bacteria. In addition, the use of mesenchymal stem cells (MSC) is an excellent option to improve wound healing due to their capability for differentiation and release of relevant growth factors. Finally, radiosterilized pig skin (RPS) is a biomatrix successfully used as wound dressing to avoid massive water loss, which represents an excellent carrier to deliver MSC into wound beds. Together, AgNPs, RPS and MSC represent a potential dressing to control massive water loss, prevent bacterial infection and enhance skin regeneration; three essential processes for appropriate wound healing with minimum scaring. RESULTS: We synthesized stable 10 nm-diameter spherical AgNPs that showed 21- and 16-fold increase in bacteria growth inhibition (in comparison to antibiotics) against clinical strains Staphylococcus aureus and Stenotrophomonas maltophilia, respectively. RPS samples were impregnated with different AgNPs suspensions to develop RPS-AgNPs nanocomposites with different AgNPs concentrations. Nanocomposites showed inhibition zones, in Kirby-Bauer assay, against both clinical bacteria tested. Nanocomposites also displayed antibiofilm properties against S. aureus and S. maltophilia from RPS samples impregnated with 250 and 1000 ppm AgNPs suspensions, respectively. MSC were isolated from adipose tissue and seeded on nanocomposites; cells survived on nanocomposites impregnated with up to 250 ppm AgNPs suspensions, showing 35% reduction in cell viability, in comparison to cells on RPS. Cells on nanocomposites proliferated with culture days, although the number of MSC on nanocomposites at 24 h of culture was lower than that on RPS. CONCLUSIONS: AgNPs with better bactericide activity than antibiotics were synthesized. RPS-AgNPs nanocomposites impregnated with 125 and 250 ppm AgNPs suspensions decreased bacterial growth, decreased biofilm formation and were permissive for survival and proliferation of MSC; constituting promising multi-functional dressings for successful treatment of skin wounds.

Nanoparticles containing curcuminoids (Curcuma longa): development of topical delivery formulation

Solid lipid nanoparticles incorporating Curcuma longa L., Zingiberaceae, curcuminoids were produced by the hot melt emulsion method. A Box–Behnken factorial design was adopted to study the nanoparticles production at different levels of factors such as the percentage of curcuminoids, time of homogenization and surfactant ratio. The optimized nanoparticles were incorporated into hydrogels for stability, drug release and skin permeation tests. The average nanoparticle sizes were 210.4 nm; the zeta potential of −30.40 ± 4.16; the polydispersivity was 0.222 ± 0.125. The average encapsulation efficiency of curcumin and curcuminoids was 52.92 ± 5.41% and 48.39 ± 6.62%, respectively. Solid lipid nanocapsules were obtained with curcumin load varying from 14.2 to 33.6% and total curcuminoids load as high as 47.7%. The topical formulation containing SLN-Curcuminoids showed good spreadability and stability when subjected to mechanical stress test remained with characteristic color, showed no phase separation and no significant change in pH. As a result of slow release, the nanoparticles were able to avoid permeation or penetration in the pig ear epidermis/dermis during 18 h. The topical formulation is stable and can be used in further in vivo studies for the treatment of inflammatory reactions, in special for radiodermitis.

Skin penetration and photoprotection of topical formulations containing benzophenone-3 solid lipid microparticles prepared by the solvent-free spray-congealing technique.

PURPOSE: Solid-lipid microparticles loaded with high amounts of the sunscreen UV filter benzophenone-3 were prepared by spray congealing with the objective of decreasing its skin penetration and evaluate whether the sunscreen's photoprotection were impaired by the microencapsulation process. METHODS: The microparticles were produced using the natural lipids carnauba wax or bees wax and three different concentrations of benzophenone-3 (30, 50 and 70%) using spray congealing technique. RESULTS: The microparticles presented properties suitable for topical application, such as spherical morphology, high encapsulation efficiency (95.53-102.2%), average particle sizes between 28.5 and 60.0 µm with polydispersivities from 1.2 to 2.5. In studies of in vitro skin penetration and preliminary stability, formulations of gel cream containing carnauba wax solid lipid microparticles and 70% benzophenone-3 when compared to the formulation added of bees wax solid-lipid microparticles containing 70% benzophenone-3, was stable considering the several parameters evaluated and were able to decrease the penetration of the UV filter into pig skin. Moreover, the formulations containing solid lipid microparticles with 70% benzophenone-3 increased the photoprotective capacity of benzophenone-3 under UV irradiation. CONCLUSION: The results show that spray-congealed microparticles are interesting solid forms to decrease the penetration solar filters in the skin without compromising their photoprotection.

Microbiota fúngica isolada da pele de suínos sadios / Fungal microbiota isolated from healthy pig skin

Researches have been developed to observe the normal microbiota of different animal species. This subject is of major importance for the control of potential infection risks. Fungi can be found in various substrates, foodstuffs (cereals, meat, milk, vegetables) and also in the skin, mucosae, respiratory and gastrointestinal tracts of animals. With the dissemination of immunosuppressive diseases in swine herds over the last years, the number of concomitant diseases caused by opportunist microorganisms is gradually increasing in literature. The objective of this study was to determine the microbiota of pig skin with no apparent lesions.(AU)

Microbiota fúngica isolada da pele de suínos sadios / Fungal microbiota isolated from healthy pig skin

Researches have been developed to observe the normal microbiota of different animal species. This subject is of major importance for the control of potential infection risks. Fungi can be found in various substrates, foodstuffs (cereals, meat, milk, vegetables) and also in the skin, mucosae, respiratory and gastrointestinal tracts of animals. With the dissemination of immunosuppressive diseases in swine herds over the last years, the number of concomitant diseases caused by opportunist microorganisms is gradually increasing in literature. The objective of this study was to determine the microbiota of pig skin with no apparent lesions.