ABSTRACT
Obesity has become an important inducer of many public diseases such as diabetes, endocrine disorders, and so on. Anti-obesity treatment has become a hot topic. Inhibiting fat synthesis and promoting fat decomposition are important ways of drug anti-obesity treatment. With the in-depth study of the distribution, morphology and function of adipose tissue, brown adipose tissue containing multi-compartment fat drops and rich mitochondria have attracted people's attention. Beige adipocytes which are similar to brown adipocytes in morphology and function have aroused great interest, such cells can be transformed from white adipocytes by external stimulation or browning agents. This process is called "white fat browning". The expression of promoting energy consumption proteins in these cells increase, so that the function of adipocytes changes from energy storage to energy consumption to increase excessive energy consumption in the body and reduce lipid accumulation. The browning of white adipose tissue has brought new ideas for obesity treatment, but the systemic administration of browning agent has the risk of adverse reactions to non-target tissues such as heart and central nervous system, which limits its application in inducing white fat browning. Browning agents to white adipose tissue can reduce its adverse reactions and improve its bioavailability by constructing a drug delivery system targeting white adipose tissue. In this review, the mechanism on browning of white adipose tissue, the commonly used browning agents and the targeted delivery carriers that induce browning of white adipose tissue are summarized.
ABSTRACT
Liposomes, as one of the most successful nanotherapeutics, have a major impact on many biomedical areas. In this study, we performed laser scanning confocal microscope (LSCM) and immunohistochemistry (IHC) assays to investigate the intra-tumor transport and antitumor mechanism of GE11 peptide-conjugated active targeting liposomes (GE11-TLs) in SMMC7721 xenograft model. According to classification of individual cell types in high resolution images, biodistribution of macrophages, tumor cells, cells with high epidermal growth factor receptor (EGFR) expression and interstitial matrix in tumor microenvironment, in addition, their impacts on intra-tumor penetration of GE11-TLs were estimated. Type I collagen fibers and macrophage flooded in the whole SMMC7721 tumor xenografts. Tumor angiogenesis was of great heterogeneity from the periphery to the center region. However, the receptor-binding site barriers were supposed to be the leading cause of poor penetration of GE11-TLs. We anticipate these images can give a deep reconsideration for rational design of target nanoparticles for overcoming biological barriers to drug delivery.
ABSTRACT
By a targeting-delivery system, drugs are delivered and concentrated in a local district such as target tissues, organs, cells or a special district of cells to avoid harm to healthy tissues. Curcumin has various pharmacological activities, but the clinical application of curcumin is severely limited by its main drawbacks including instability, low solubility and poor bioavailability. Recently curcurnin-targeting dosage forms which improved the curcumin bioavailability surged. In this article, the new targeting-delivery systems and their use in curcumin delivery mainly including liposomes, ligand-receptors, magnetic iron oxides and other systems are reviewed in design methodologies and bioactive effects. Advantages and disadvantages for the target-delivery systems are discussed.