Sustained epidermal powder drug delivery via skin microchannels

Transdermal delivery of hydrophilic drugs is challenging. This study presents a novel sustained epidermal powder delivery technology (sEPD) for safe, efficient, and sustained delivery of hydrophilic drugs across the skin. sEPD is based on coating powder drugs into high-aspect-ratio, micro-coating channels (MCCs) followed by topical application of powder drug-coated array patches onto ablative fractional laser-generated skin MCs to deliver drugs into the skin. We found sEPD could efficiently deliver chemical drugs without excipients and biologics drugs in the presence of sugar excipients into the skin with a duration of ~ 12 h. Interestingly the sEPD significantly improved zidovudine bioavailability by ~ 100% as compared to oral gavage delivery. sEPD of insulin was found to maintain blood glucose levels in normal range for at least 6 h in chemical-induced diabetes mice, while subcutaneous injection failed to maintain blood glucose levels in normal range. sEPD of anti-programmed death-1 antibody showed more potent anti-tumor efficacy than intraperitoneal injection in B16F10 melanoma models. Tiny skin MCs and ‘bulk’ drug powder inside relatively deep MCCs are crucial to induce the sustained drug release. The improved bioavailability and functionality warrants further development of the novel sEPD for clinical use

Vascular-targeted nanotherapy for obesity: Unexpected passive targeting mechanism to obese fat for the enhancement of active drug delivery

We previously reported that nanoparticles (NPs) modified with a prohibitin- homing peptide ligand via a short PEG_[2kDa]-spacer could deliver its pay-load into the cytoplasm of endothelial cells in murine adipose tissue and escape from endosomes/lysosomes in vitro. We herein report, for the first time, on a dual-targeting strategy for mediating the enhanced targeting activity of NPs to adipose endothelial cells in diet-induced obesity (DIO). The targeted accumulation of prohibitin-targeted nanoparticles (PTNP), modified with a peptide ligand via a long PEG-linker, was significantly increased in white fat vessels of normal healthy mice compared to the other non-PEGylated targeted NPs, whereas the undesired accumulation of PTNP in the liver was considerably reduced. These results demonstrate that the PEGylation of targeted NPs is a critical factor in maximizing the in vivo targeted delivery of NPs and can be attributed to a significant decrease in recognition by the reticuloendothelial system. After systemic administration to DIO mice, PTNP exclusively accumulated in both adipose vessels and angiogenic clusters of obese fat cells. Surprisingly, PEGylated NPs with no active targeting moieties also accumulated in these clusters, demonstrating that the nanoscaled carriers passively accumulate in clusters via a mechanism similar to that for the enhanced permeability and retention effect, as has been well established in tumor targeting. Therefore, the enhanced delivery of PTNP appears to be mediated by both passive accumulation to angiogenic regions and active recognition by endothelial cells. Thus, the systemic administration of a proapoptotic peptide with the delivery via PTNP significantly reduced the body weight of DIO mice, as evidenced by the targeted ablation of adipose endothelial cells. These findings are potentially useful in terms of the design and development of vascular-targeted nanotherapy in the effective control of obesity

A comparative study between nanoparticle-targeted therapeutics and bioconjugates as obesity medication

Antiangiogenesis has been the focus of a new strategy for the treatment of obesity. However, little is known regarding the issue of whether targeting angiogenesis by nanoparticle-targeted therapeutic is advantageous or not in debugging the co-morbidity associated with diet-induced obesity (DIO) and the metabolic syndrome. We report herein on the positive effect of prohibitin (an adipose vascular marker)-targeted nanoparticle (PTNP) encapsulated in a proapoptotic peptide [(D)(KLAKLAK)(2), KLA] on DIO and dysfunctional adipose tissue, a major mediator of the metabolic syndrome, as evidenced by ectopic fat deposition. The systemic injection of DIO mice with a low dose of KLA-PTNP, rather than a bioconjugate composed of the same targeting peptide and KLA (Adipotide) resulted in a reduction in body weight, as evidenced by a significant decrease in serum leptin levels, in parallel with an antiobesity effect on dysfunctional adipose cells, including adipocytes and macrophages. In addition, the KLA-PTNP treatment resulted in a reduction in ectopic fat deposits in liver and muscle with the lipolytic action of elevated serum adiponectin, with no detectable hepatoxicity. Notably, drug delivery via PTNP that had accumulated in obese fat via the enhanced permeability and retention effect was enhanced by multivalent active targeting and cytoplasmic delivery into adipose endothelial cells via escaping from endosomes/lysosomes. Thus, vascular-targeted nanotherapy has the potential to contribute to the control of adipose function and ectopic fat deposition associated with obesity and the metabolic syndrome. (C) 2013 Elsevier B. V. All rights reserved

Therapeutic Assessment of Cytochrome C for the Prevention of Obesity Through Endothelial Cell-targeted Nanoparticulate System

Because the functional apoptosis-initiating protein, cytochrome C (CytC) is rapidly cleared from the circulation (t(1/2) (half-life): 4 minutes), it cannot be used for in vivo therapy. We report herein on a hitherto unreported strategy for delivering exogenous CytC as a potential and safe antiobesity drug for preventing diet-induced obesity, the most common type of obesity in humans. The functional activity of CytC encapsulated in prohibitin (a white fat vessel-specific receptor)-targeted nanoparticles (PTNP) was evaluated quantitatively, as evidenced by the observations that CytC-loaded PTNP causes apoptosis in primary adipose endothelial cells in a dose-dependent manner, whereas CytC alone did not. The delivery of a single dose of CytC through PTNP into the circulation disrupted the vascular structure by the targeted apoptosis of adipose endothelial cells in vivo. Intravenous treatment of CytC-loaded PTNP resulted in a substantial reduction in obesity in high-fat diet (HFD) fed wild-type (wt) mice, as evidenced by the dose-dependent prevention of the percentage of increase in body weight and decrease in serum leptin levels. In addition, no detectable hepatotoxicity was found to be associated with this prevention. Thus, the finding highlights the promising potential of CytC for use as an antiobesity drug, when delivered through a nanosystem

Ligand-based targeted delivery of a peptide modified nanocarrier to endothelial cells in adipose tissue

Ligand-based targeted delivery is an emerging platform in nanomedicine. We report herein on a peptide modified nanocarrier for a ligand-based targeted delivery system. The liposomal surface of the carrier was first modified with a linear peptide, followed by an adipose tissue-specific circular peptide (KGGRAKD) via a polyethylene glycol (PEG) spacer. To evaluate the specificity of the carrier, we purified primary cells from the endothelium of adipose tissue. The liposomes bound only to isolated primary cultured endothelial cells derived from inguinal adipose tissue (pcEC-IWAT) and not to other endothelial cell lines, such as MBEC-4 and MFLM-4. Cellular uptake was confirmed both qualitatively and quantitatively by confocal laser scanning microscopy (CLSM) and flow cytometry. The mechanism for the intracellular uptake of tPep-PEG-LPs into pcEC-IWAT, as evidenced by three independent experiments, involves saturation of receptor binding sites by excess free peptide, the blocking of receptors by an anti-prohibitin antibody and low temperature (4℃) experiments, resulting in the inhibition of up-take of tPep-PEG-LPs into pcEC-IWAT, suggesting that receptor mediated endocytosis largely contributed to the observed cellular uptake. A co-localization study using double labeled modified liposomes (lipid membrane: NBD-DOPE and aqueous phase: rhodamine) indicated that a predominant part of tPep-PEG-LPs was found without co-localization with lysosomes and retained their intactness. The selective delivery of tPep-PEG-LPs to endothelial cells in adipose tissue represents a potential approach for the design of diverse nanocarrier-based targeted delivery systems for targeting the vasculature in adipose tissue

Isolation and culture of microvascular endothelial cells from murine inguinal and epididymal adipose tissues

Adipose tissue has long been considered to be a simple tissue that contains adipocytes. Because of this, the isolation and characterization of microvascular endothelical cells, which are also present in adipose tissue, have been neglected, even though they are components of a capillary network that surrounds each individual adipocyte. Here we report on a protocol for producing highly purified murine microvascular endothelial cells (MECs) from diverse sites of murine adipose tissues including inguinal and epididymal adipose tissues. The method is based on a combination of negative and positive immunomagnetic selection. The protocol involves the preparation of a single cell suspension (digestion, filtration and density gradient centrifugation), immunomagnetic enrichment of the CD45- cell population and the purification of the MECs by a combination of common specific markers CD31, CD102 and isolectin B4. The isolated MECs can be successively cultured for 10 to 12 passages without any detectable changes in morphology and phenotype. Therefore, the method described herein represents a protocol for the isolation and long-term maintenance of highly pure mouse MECs in high yields from adipose tissues

Augmentation of vaccine-induced humoral and cellular immunity by a physical radiofrequency adjuvant

Vaccine adjuvants ensure sufficient engagement of the immune system in vaccination, however safety issues can be associated with novel chemical adjuvants. Here, Cao et al. report a physical radiofrequency adjuvant to simultaneously augment vaccine-induced humoral and cellular immune responses without potentially harmful adverse reactions