1,721,051 research outputs found
Ceramide and apoptosis
No full textAbstract
Ceramide is a sphingosine-based lipid second messeger molecule that is involved in regulation of differentiation, proliferation, apoptosis, or growth arrest. The pleiotropic nature of ceramide signalling may be due to the fact that it is linked to a variety of receptors in different cell types. Since the ceramide is one of the most hydrophobic molecules in mammalian cells, it tends to remain within the membrane bilayer and may exert its function exclusively at the subcellular site of production. Ceramide is generated from sphingomyelin (SM) by the action of several isoforms of SMase (neutral, acid and alkaline SMase) or by de novo synthesis co-ordinated through the enzyme ceramide synthase. In this chapter, the pathways of ceramide generation, the interaction of ceramide with several enzymes and apoptotic signalling cascades are describ
Liposomes as biomimetic microreactors
No full textLiposomes have become an important model in fundamental biomembrane research, including biophysical, biochemical, and cell biological studies of membranes and cell function. They are thoroughly studied in several applications, such as drug delivery systems in medical applications and as controlled release systems, microencapsulating media, signal carriers, support matrices, and solubilizers in other applications. While medical applications have been extensively reviewed in recent literature, there is a need for easily accessible information on applications for liposomes beyond pharmacology and medicine. The Handbook of Nonmedical Applications of Liposomes fills this void.
This unique new handbook series presents recent developments in the use of liposomes in many scientific disciplines, from studies on the origin of life, protein function, and vesicle shapes, to applications in cosmetics, diagnostics, ecology, bioreclamation, and the food industry. In these volumes many of the top experts contribute extensive reviews of their work
Extracellular vesicle therapeutics from plasma and adipose tissue
No full textExtracellular vesicles (EVs) are cell-released lipid-bilayer nanoparticles that contain biologically active cargo involved in physiological and pathological intercellular communication. In recent years, the therapeutic potential of EVs has been explored in various disease models. In particular, mesenchymal stromal cell-derived EVs have been shown to exert anti-inflammatory, anti-oxidant, anti-apoptotic, and pro-angiogenic properties in cardiovascular, metabolic and orthopedic conditions. However, a major drawback of EV-based therapeutics is scale-up issues due to extensive cell culture requirements and inefficient isolation protocols. An emerging alternative approach to time-consuming and costly cell culture expansion is to obtain therapeutic EVs directly from the body, for example, from plasma and adipose tissue. This review discusses isolation methods and therapeutic applications of plasma and adipose tissue-derived EVs, highlighting advantages and disadvantages compared to cell culture-derived ones
Increase of skin-ceramide levels in aged subjects following a short-term topical application of bacterial sphingomyelinase from Streptococcus thermophilus.
Full text linkSeveral studies have demonstrated that ceramides play an essential role in both the barrier and water-holding functions of healthy stratum corneum, suggesting that the dysfunction of the stratum corneum associated with ageing as well that observed in patients with several skin diseases could result from a ceramide deficiency. In a previous study our group reported a significant increase in skin ceramide levels in healthy subjects after treatment in vivo with a cream containing a preparation of Streptococcus thermophilus. The presence of high levels of neutral sphingomyelinase activity in this organism was responsible for the observed increase of stratum corneum ceramide levels, thus leading to an improvement in barrier function and maintenance of stratum corneum flexibility. The aim of the present work is to investigate the effects of the topical treatment of a Streptococcus thermophilus-containing cream on ceramide levels of stratum corneum of healthy elderly women. The ceramide levels, transepidermal water loss and capacitance were evaluated on stratum corneum sheets from the forearms of 20 healthy female subjects treated with a base cream or the same cream containing a sonicated preparation of the lactic acid bacterium Streptococcus thermophilus. A 2-week topical application of a sonicated Streptococcus thermophilus preparation led to significant and relevant increase of stratum corneum ceramide levels. Moreover, the hydration values of the treated forearm of each subject was significantly higher than control sites. These results suggest that the experimental cream was able to improve the lipid barrier and to increase a resistance against ageing-associated xerosis
Novel pH-sensitive Tween® 21 vesicles: preparation and characterization compared with Tween® 20 ones.
No full textDiscoidal Nanoparticles: reaction environment-dependent Size Response
No full textIn recent years, the develop of new drug delivery system (DDS) was necessary to optimize the treatment efficiency, thus overcoming the limits of traditional teraphy such as targeting and drug half life. However, many treatmants cause immunogenicity. Several DDS was developed such as liposomes, niosomes and other tipe of nanoparticles, but they can have some limits like the recognition and elimination of the immune system or the tumour targeting. These drawbacks can be bypassed by modifing sizes and shapes of liposomes. Discoidal Nanopartcles (DNs) are obtained from liposomes by adding Styrene-Maleic Acid copolimer (SMA) (Fig. 1). The molecular ratio between styrene and maleic anhydride, pH and temperature of microenvironment reaction can affect the synthesis of DNs [1]. In this work we studied the use of SMA as copolymer, which is able to synthesis DNs by starting from spherical liposomes (DMPC) at different molar ratio of copolymers (2:1 and 4:1), pHs (range of pH from 3.5 to 11.5) and temperatures (4°C, 25°C, 37°C, 65°C).
The SMA copolymer can form DNs, and their properties depend on the reaction enviroment. In fact, at different pHs, particle sizes are modified according to these physical parameters. The modifcation of temperature can influence the synthesis of DNs. Currently, the best condition is obtained at pH = 7.4 and 25°C by using 2:1 molar ratio of copolymer. The results are in agreement with previously reported data using SMA as a copolymer under different reaction conditions [1]. These properties could be affected the synthesis of DNs as well as drug delivery, but DNs could be a innovative DDS for anticancer therapy.
Acknowledgment: This research is funded by the Italian Ministry of Instruction, University, and Research under the national project PON Ricerca e Innovazione 2014-2020
Sistemi Vescicolari Non-fosfolipidici: Potenziali Applicazioni nella Somministrazione Orale.
No full textDeterminazione in campioni biologici di sonde fluorescent veicolate in strutture vescicolari non fosfolipidiche mediante HPLC-FLD e spettrofotometria
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