Background Ceramide hydrolysis by ceramidase in the stratum corneum (SC) yields both sphingoid bases and free fatty acids (FFA). While FFA are key constituents of the lamellar bilayers that mediate the epidermal permeability barrier, whether sphingoid bases influence permeability barrier homeostasis remains unknown. Pertinently, alterations of lipid profile, including ceramide and ceramidase activities occur in atopic dermatitis (AD). Object We investigated alterations in sphingoid base levels and/or profiles (sphingosine to sphinganine ratio) in the SC of normal vs. AD mice, a model that faithfully replicates human AD, and then whether altered sphingoid base levels and/or profiles influence(s) membrane stability and/or structures. Methods Unilamellar vesicles (LV), incorporating the three major SC lipids (ceramides/FFA/cholesterol) and different ratios of sphingosine/sphinganine, encapsulating carboxyfluorescein, were used as the model of SC lipids. Membrane stability was measured as release of carboxyfluorescein. Thermal analysis of LV was conducted by Differential scanning calorimetry (DSC). Results LV containing AD levels of sphingosine/sphinganine (AD-LV) displayed altered membrane permeability vs. normal-LV. DSC analyses revealed decreases in orthorhombic structures that form tightly-packed lamellar structures in AD-LV. Conclusion Sphingoid base composition influences lamellar membrane architecture in SC, suggesting that altered sphingoid base profiles could contribute to the barrier abnormality in AD.
Construction of small and continuous capillary networks is a fundamental challenge for the development of threedimensional (3D) tissue engineering. In particular, to construct mature and stable capillary networks, it is important to consider interactions between endothelial cells and pericytes. This study aimed to construct stable capillary networks covered by pericyte-like perivascular cells, which maintain the lumen of small diameter similar to that of capillary structures in vivo. Vascular sprouting, capillary extension, and stabilization were investigated using a 3D angiogenesis model containing human umbilical vein endothelial cells (HUVECs) and mesenchymal stem cells (MSCs) in a microfluidic device. A series of HUVEC:MSC ratios was tested; the ratio was found to be an important factor in the construction of capillary structures. We found that stable capillary networks that were covered by MSC-derived perivascular cells can be constructed at 1:1 HUVEC:MSC ratio. The constructed capillary networks had continuous lumens with <10-mm diameter, which were maintained for at least 21 days. This angiogenic process and basement membrane formation were regulated by HUVEC-MSC interactions.
Menthosomes, novel deformable carriers for the enhancement of transdermal delivery are introduced in this study. Meloxicam (MX)-loaded menthosomes were formulated, and their physicochemical characteristics and skin permeability were evaluated. A two-factor spherical and second-order composite experimental design was used to prepare the formulation of the menthosomes. Ten formulations of menthosomes composed of a phospholipid as the lipid bilayer carrier, cholesterol (Chol) as a stabilizer and cetylpyridinium chloride (CPC) and L-menthol as penetration enhancers were prepared. The amounts of Chol and CPC were selected as causal factors. Physicochemical characteristics (particle size, size distribution, zeta potential, elasticity and drug content) and an in vitro skin-permeation study of meloxicam-loaded menthosomes were evaluated. The concentrations of MX that permeated the skin at 2-12 h and the flux were selected as response variables. The optimal formulation was estimated using a nonlinear response-surface method incorporating thin-plate spline interpolation. The experimental values were very close to the values predicted by the computer programs in this study. A Bayesian network analysis was applied to gain a mechanistic understanding of the relationships between causal factors and response variables.Key words menthosome; liposome; optimization; skin permeation; meloxicam; menthol For the past few decades, the use of liposomal vesicles in drug-delivery systems for skin permeation has evoked considerable interest and attracted increasing attention. Many reports focus on the use of liposomes for enhancing skin permeation of hydrophilic and lipophilic compounds, proteins and macromolecules. However, recent studies indicate that in most cases, classic liposomes are of little or no value as transdermal drug-delivery carriers because they do not penetrate skin deeply, but rather remain confined to the upper layers of the stratum corneum. Confocal microscopic studies showed that intact fluorescent labeled liposomes were not able to penetrate into the granular layers of the epidermis. 1)Since the first paper to report the effectiveness of deformable liposomes which can be used for skin delivery of drug into deep skin region was published by Cevc and Blume, 2) new categories of vesicles with high elasticity or flexibility, such as transfersomes,3) ethosomes, 4) flexosomes 5) and invasomes 6) have been introduced and developed. These vesicles mainly consist of phospholipids and an edge activator or penetration enhancer in which only a specially designed vesicle was shown to be able to allow transdermal drug delivery. Menthosomes, novel deformable carriers consist of phospholipids, surfactant and menthol were also introduced in this study. Several intensive studies suggested that the permeability of drug in liposomes and their analogues depends on their physicochemical characteristics (e.g., particle size, size distribution, zeta potential, lamellarity, elasticity, drug content, etc.), and these characteristics were dir...
In the present study, novel ultradeformable liposomes (menthosomes; MTS), deformable liposomes (transfersomes; TFS) and conventional liposomes (CLP) were compared in their potential for transdermal delivery of meloxicam (MX). MTS, TFS and CLP were investigated for size, size distribution, zeta potential, elasticity, entrapment efficiency and stability. In vitro skin permeation using hairless mice skin was evaluated. Vesicular morphology was observed under freeze-fractured transmission electron microscopy (FF-TEM). Intrinsic thermal properties were performed using differential scanning calorimetry (DSC) and X-ray diffraction. The skin permeation mechanism was characterized using confocal laser scanning microscopy (CLSM). The results indicated that the difference in physicochemical characteristics of MTS, TFS and CLP affected the skin permeability. MTS and TFS showed higher flux of MX than CLP. CLSM image showed deformable vesicles mechanism for delivery of MX across the hairless mice skin. Our study suggested that ultradeformable and deformable liposomes (MTS and TFS) had a potential to use as transdermal drug delivery carriers for MX.Key words menthosome; transfersome; liposome; skin permeation; meloxicam; menthol Meloxicam (MX), a cyclooxygenase-2 inhibitor nonsteroidal anti-inflammatory drug (NSAID), is used to treat rheumatoid arthritis, osteoarthritis and other joint diseases. The injectable and oral administrations of NSAID drugs are not appropriate for needle-phobia and peptic ulcer patients. Moreover, the major limitation of MX is its low aqueous solubility (0.012 mg/mL in water and 0.086×10 −2 mg/mL in 0.1 M HCl) 1) with log P 1.91 and 0.07 at pH 5.0 and 7.4, respectively. MX delays its absorption from gastrointestinal tract (GI) and its prolonged use is associated with the incidence of GI side effects (bellyache, indigestion, ulceration and bleeding).2) If MX could be delivered without incidence of these limitations, MX administration would become safer and more acceptable. MX is suitable for development as a transdermal delivery candidate.Transdermal drug delivery or skin delivery has become a global priority because the conventional drug administration is associated with numerous limitations. Liposomes are one of potential strategies that utilize for skin delivery of hydrophilic drugs, 3) lipophilic drugs, 4) protein 5) and macromolecule.6) Although last decades, some design of conventional liposomes are of little or no value as carriers for transdermal drug delivery, but rather remain confined to the upper layer of the stratum corneum. However, recent approaches in vesicular modulating drug delivery through skin have resulted in many designs of novel vesicular carriers e.g., deformable liposomes (transfersomes), 7) niosomes, 8) ethosomes, 9) invasomes, 10) flexosomes 11) and menthosomes. 12) Transfersomes are the first generation of elastic vesicles introduced by Cevc and Blune 7) and consist mainly of phospholipids and an edge activator or a single-chain surfactant which having a high radius of curv...
Vascular networks consist of hierarchical structures of various diameters and are necessary for efficient blood distribution. Recent advances in vascular tissue engineering and bioprinting have allowed us to construct large vessels, such as arteries, small vessels, such as capillaries and microvessels, and intermediate-scale vessels, such as arterioles, individually. However, little is known about the control of vessel diameters between small vessels and intermediate-scale vessels.Here, we focus on vascular remodeling, which creates lasting structural changes in the vessel wall in response to hemodynamic stimuli, to regulate vessel diameters in vitro. The purpose of this study is to control the vessel diameter at an intermediate scale by inducing outward remodeling of microvessels in vitro. Human umbilical vein endothelial cells and mesenchymal stem cells were cocultured in a microfluidic device to construct microvessels, which were then perfused with a culture medium to induce outward vascular remodeling. We successfully constructed vessels with diameters of 40-150 µm in perfusion culture, whereas vessels with diameters of <20 µm were maintained in static culture. We also revealed that the in vitro vascular remodeling was mediated by NO pathways and MMP-9. These findings provide insight into the regulation of diameters of tissue-engineered blood vessels. This is an important step toward the construction of hierarchical vascular networks within biofabricated three-dimensional systems.
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