Stage-dependent modulation of limb regeneration by caffeic acid phenethyl ester (CAPE)--immunocytochemical evidence of a CAPE-evoked delay in mesenchyme formation and limb regeneration

An Insight into the Structural Diversity and Clinical Applicability of Polyurethanes in Biomedicine

Due to their mechanical properties, ranging from flexible to hard materials, polyurethanes (PUs) have been widely used in many industrial and biomedical applications. PUs' characteristics, along with their biocompatibility, make them successful biomaterials for short and medium-duration applications. The morphology of PUs includes two structural phases: hard and soft segments. Their high mechanical resistance featuresare determined by the hard segment, while the elastomeric behaviour is established by the soft segment. The most important biomedical applications of PUs include antibacterial surfaces and catheters, blood oxygenators, dialysis devices, stents, cardiac valves, vascular prostheses, bioadhesives/surgical dressings/pressure-sensitive adhesives, drug delivery systems, tissue engineering scaffolds and electrospinning, nerve generation, pacemaker lead insulation and coatings for breast implants. The diversity of polyurethane properties, due to the ease of bulk and surface modification, plays a vital role in their applications.

Cytotoxic, Antimicrobial, Antioxidant Properties and Effects on Cell Migration of Phenolic Compounds of Selected Transylvanian Medicinal Plants

Medicinal plants are widely used in folk medicine but quite often their composition and biological effects are hardly known. Our study aimed to analyze the composition, cytotoxicity, antimicrobial, antioxidant activity and cellular migration effects of Anthyllis vulneraria, Fuchsia magellanica, Fuchsia triphylla and Lysimachia nummularia used in the Romanian ethnomedicine for wounds. Liquid chromatography with mass spectrometry (LC-MS/MS) was used to analyze 50% (v/v) ethanolic and aqueous extracts of the plants’ leaves. Antimicrobial activities were estimated with a standard microdilution method. The antioxidant properties were evaluated by validated chemical cell-free and biological cell-based assays. Cytotoxic effects were performed on mouse fibroblasts and human keratinocytes with a plate reader-based method assessing intracellular adenosine triphosphate (ATP), nucleic acid and protein contents and also by a flow cytometer-based assay detecting apoptotic–necrotic cell populations. Cell migration to cover cell-free areas was visualized by time-lapse phase-contrast microscopy using standard culture inserts. Fuchsia species showed the strongest cytotoxicity and the highest antioxidant and antimicrobial activity. However, their ethanolic extracts facilitated cell migration, most probably due to their various phenolic acid, flavonoid and anthocyanin derivatives. Our data might serve as a basis for further animal experiments to explore the complex action of Fuchsia species in wound healing assays.

The incorporation of Brazilian propolis into collagen-based dressing films improves dermal burn healing

ETHNOPHARMACOLOGICAL RELEVANCE

Hydroalcoholic solutions of propolis, a resinous product produced by bees, have been currently employed in improving the cicatricial repair. Biological activity of propolis might be related to its antimicrobial, anti-inflammatory and immunomudalatory properties.

AIM OF THIS STUDY

Investigate the suitability of the collagen-based films containing hydroalcoholic extracts of two different varieties of Brazilian propolis (green and red ones) on the dermal burn healing in rodent model.

MATERIALS AND METHODS

The hydroalcoholic extracts of red propolis (RP) or Green propolis (GP) were incorporated into collagen-based dressing films (COL). Burn wounds were performed in the dorsum of Wistar rats and dressing with COL, COL+GPa (0.5%), COL+GPb (1,0%) or COL+RP (0.5%). A control group (CTR) was performed keeping the wound undressed. The histological analyses were carried out after 3, 7, 14, 21 and 30 days for histological assessment of the inflammatory response, epithelization rates (ER), myofibroblastic count (MC) and collagenization pattern.

RESULTS

GPa, GPb and RP provided significant decrease of the inflammatory severity, improved the ER in GPa in 7 (p=0.000), 14 (p=0.000), 21 (p=0.005) and 30 days (p=0.015), and induced earlier replacement of type-III for type-I collagen (p<0.05) than COL and CTR. In all the groups, the MC increased progressively from 3 to 14 days, and then started to decrease slowly until 21 days. Although no significant difference was observed among the groups in 3, 7 and 30 days, the MC was significantly increased in RP in 14 (p=0.0001) and 21 days (p=0.04), as well as grosser interlacement of the collagen bundles compared with the other groups.

CONCLUSION

The incorporation of hydroalcoholic extracts of Brazilian propolis improved the biological events associated to burn healing without toxic effects, but the red variety provided the best results. Therefore, these collagen-based containing natural apicultural products films may be considered a promising new dressing for wound occlusion and tissue repairing.

Propolis induces chondroitin/dermatan sulphate and hyaluronic Acid accumulation in the skin of burned wound

Changes in extracellular matrix glycosaminoglycans during the wound repair allowed us to apply the burn model in which therapeutic efficacy of propolis and silver sulfadiazine was compared. Burns were inflicted on four pigs. Glycosaminoglycans isolated from healthy and burned skin were quantified using a hexuronic acid assay, electrophoretic fractionation, and densitometric analyses. Using the reverse-phase HPLC the profile of sulfated disaccharides released by chondroitinase ABC from chondroitin/dermatan sulfates was estimated. Chondroitin/dermatan sulfates and hyaluronic acid were found in all samples. Propolis stimulated significant changes in the content of particular glycosaminoglycan types during burn healing. Glycosaminoglycans alterations after silver sulfadiazine application were less expressed. Propolis maintained high contribution of 4-O-sulfated disaccharides to chondroitin/dermatan sulfates structure and low level of 6-O-sulfated ones throughout the observed period of healing. Propolis led to preservation of significant contribution of disulfated disaccharides especially 2,4-O-disulfated ones to chondroitin sulfates/dermatan sulfates structure throughout the observed period of healing. Our findings demonstrate that propolis accelerates the burned tissue repair by stimulation of the wound bed glycosaminoglycan accumulation needed for granulation, tissue growth, and wound closure. Moreover, propolis accelerates chondroitin/dermatan sulfates structure modification responsible for binding growth factors playing the crucial role in the tissue repair.

Properties of BK(Ca) channels in oral keratinocytes

Keratinocytes are important for epithelial antimicrobial barrier function. The activity of ion channels can affect the proliferation of keratinocytes. Little is known about Ca2+-activated K+ currents in these cells. Ion currents in normal human oral keratinocytes were characterized with a patch-clamp technique. In whole-cell configuration, depolarizing pulses evoked K+ outward currents (I(K)) in oral keratinocytes. Iberiotoxin (200 nM) and paxilline (1 microM) suppressed I(K); however, neither apamin (200 nM) nor 5-hydroxydecanoate (30 microM) had any effects on it. Caffeic acid phenethyl ester, a compound of honeybee propolis, increased I(K) with an EC50 value of 12.8 +/- 1.2 microM. In inside-out patches, a BK(Ca) channel was observed in keratinocytes, but not in oral squamous carcinoma (OCE-M1) cells. Caffeic acid phenethyl ester or cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate applied to the intracellular surface of a detached patch increased BK(Ca)-channel activity. The results demonstrate that the properties of BK(Ca) channels in normal human oral keratinocytes are similar to those described in other types of cells. Caffeic acid derivatives can also stimulate BK(Ca)-channel activity directly.