In Vivo Delivery and Therapeutic Effects of a MicroRNA on Colorectal Liver Metastases.

Multiple therapeutic agents are typically used in concert to effectively control metastatic tumors. Recently, we described microRNAs that are associated with the oligometastatic state, in which a limited number of metastatic tumors progress to more favorable outcomes. Here, we report the effective delivery of an oligometastatic microRNA (miR-655-3p) to colorectal liver metastases using nanoscale coordination polymers (NCPs). The NCPs demonstrated a targeted and prolonged distribution of microRNAs to metastatic liver tumors. Tumor-targeted microRNA miR-655-3p suppressed tumor growth when co-delivered with oxaliplatin, suggesting additive or synergistic interactions between microRNAs and platinum drugs. This is the first known example of systemically administered nanoparticles delivering an oligometastatic microRNA to advanced metastatic liver tumors and demonstrating tumor-suppressive effects. Our results suggest a potential therapeutic strategy for metastatic liver disease by the co-delivery of microRNAs and conventional cytotoxic agents using tumor-specific NCPs.

Hybrid, metal oxide-peptide amphiphile micelles for molecular magnetic resonance imaging of atherosclerosis.

BACKGROUND: Atherosclerosis, a major source of cardiovascular disease, is asymptomatic for decades until the activation of thrombosis and the rupture of enlarged plaques, resulting in acute coronary syndromes and sudden cardiac arrest. Magnetic resonance imaging (MRI) is a noninvasive nuclear imaging technique to assess the degree of atherosclerotic plaque with high spatial resolution and excellent soft tissue contrast. However, MRI lacks sensitivity for preventive medicine, which limits the ability to observe the onset of vulnerable plaques. In this study, we engineered hybrid metal oxide-peptide amphiphile micelles (HMO-Ms) that combine an inorganic, magnetic iron oxide or manganese oxide inner core with organic, fibrin-targeting peptide amphiphiles, consisting of the sequence CREKA, for potential MRI imaging of thrombosis on atherosclerotic plaques. RESULTS: Hybrid metal oxide-peptide amphiphile micelles, consisting of an iron oxide (Fe-Ms) or manganese oxide (Mn-Ms) core with CREKA peptides, were self-assembled into 20-30 nm spherical nanoparticles, as confirmed by dynamic light scattering and transmission electron microscopy. These hybrid nanoparticles were found to be biocompatible with human aortic endothelial cells in vitro, and HMO-Ms bound to human clots three to five times more efficiently than its non-targeted counterparts. Relaxivity studies showed ultra-high r2 value of 457 mM-1 s-1 and r1 value of 0.48 mM-1 s-1 for Fe-Ms and Mn-Ms, respectively. In vitro, MR imaging studies demonstrated the targeting capability of CREKA-functionalized hybrid nanoparticles with twofold enhancement of MR signals. CONCLUSION: This novel hybrid class of MR agents has potential as a non-invasive imaging method that specifically detects thrombosis during the pathogenesis of atherosclerosis.

Shape Effects of Peptide Amphiphile Micelles for Targeting Monocytes.

Peptide amphiphile micelles (PAMs) are a nanoparticle platform that have gained popularity for their targeting versatility in a wide range of disease models. An important aspect of micelle design is considering the type of hydrophobic moiety used to synthesize the PAM, which can act as a contributing factor regarding their morphology and targeting capabilities. To delineate and compare the characteristics of spherical and cylindrical micelles, we incorporated the monocyte-targeting chemokine, monocyte chemoattractant protein-1 (MCP-1), into our micelles (MCP-1 PAMs). We report that both shapes of nanoparticles were biocompatible with monocytes and enhanced the secondary structure of the MCP-1 peptide, thereby improving the ability of the micelles to mimic the native MCP-1 protein structure. As a result, both shapes of MCP-1 PAMs effectively targeted monocytes in an in vitro binding assay with murine monocytes. Interestingly, cylindrical PAMs showed a greater ability to attract monocytes compared to spherical PAMs in a chemotaxis assay. However, the surface area, the multivalent display of peptides, and the zeta potential of PAMs may also influence their biomimetic properties. Herein, we introduce variations in the methods of PAM synthesis and discuss the differences in PAM characteristics that can impact the recruitment of monocytes, a process associated with disease and cancer progression.

Nanoscale Coordination Polymers Codeliver Chemotherapeutics and siRNAs to Eradicate Tumors of Cisplatin-Resistant Ovarian Cancer.

Drug resistance impedes the successful treatment of many types of cancers, especially ovarian cancer (OCa). To counter this problem, we developed novel long-circulating, self-assembled core-shell nanoscale coordination polymer (NCP) nanoparticles that efficiently deliver multiple therapeutics with different mechanisms of action to enhance synergistic therapeutic effects. These NCP particles contain high payloads of chemotherapeutics cisplatin or cisplatin plus gemcitabine in the core and pooled siRNAs that target multidrug resistant (MDR) genes in the shell. The NCP particles possess efficient endosomal escape via a novel carbon dioxide release mechanism without compromising the neutral surface charge required for long blood circulation and effectively downregulate MDR gene expression in vivo to enhance chemotherapeutic efficacy by several orders of magnitude. Even at low doses, intraperitoneal injections of nanoparticles led to effective and long-lasting tumor regression/eradication in subcutaneous and intraperitoneal xenograft mouse models of cisplatin-resistant OCa. By silencing MDR genes in tumors, self-assembled core-shell nanoparticles promise a more effective chemotherapeutic treatment for many challenging cancers.

Nanoscale Coordination Polymers Codeliver Carboplatin and Gemcitabine for Highly Effective Treatment of Platinum-Resistant Ovarian Cancer.

Due to the ability of ovarian cancer (OCa) to acquire drug resistance, it has been difficult to develop efficient and safe chemotherapy for OCa. Here, we examined the therapeutic use of a new self-assembled core-shell nanoscale coordination polymer nanoparticle (NCP-Carbo/GMP) that delivers high loadings of carboplatin (28.0 ± 2.6 wt %) and gemcitabine monophosphate (8.6 ± 1.5 wt %). A strong synergistic effect was observed between carboplatin and gemcitabine against platinum-resistant OCa cells, SKOV-3 and A2780/CDPP, in vitro. The coadministration of carboplatin and gemcitabine in the NCP led to prolonged blood circulation half-life (11.8 ± 4.8 h) and improved tumor uptake of the drugs (10.2 ± 4.4% ID/g at 24 h), resulting in 71% regression and 80% growth inhibition of SKOV-3 and A2780/CDDP tumors, respectively. Our findings demonstrate that NCP particles provide great potential for the codelivery of multiple chemotherapeutics for treating drug-resistant cancer.

Metal-organic frameworks as sensory materials and imaging agents.

Metal-organic frameworks (MOFs) are a class of hybrid materials self-assembled from organic bridging ligands and metal ion/cluster connecting points. The combination of a variety of organic linkers, metal ions/clusters, and structural motifs can lead to an infinite array of new materials with interesting properties for many applications. In this Forum Article, we discuss the design and applications of MOFs in chemical sensing and biological imaging. The first half of this article focuses on the development of MOFs as chemical sensors by highlighting how unique attributes of MOFs can be utilized to enhance sensitivity and selectivity. We also discuss some of the issues that need to be addressed in order to develop practically useful MOF sensors. The second half of this article focuses on the design and applications of nanoscale MOFs (NMOFs) as imaging contrast agents. NMOFs possess several interesting attributes, such as high cargo loading capacity, ease of postmodification, tunable size and shape, and intrinsic biodegradability, to make them excellent candidates as imaging contrast agents. We discuss the use of representative NMOFs in magnetic resonance imaging (MRI), X-ray computed tomography (CT), and optical imaging. Although still in their infancy, we believe that the compositional tunability and mild synthetic conditions of NMOF imaging agents should greatly facilitate their further development for clinical translation.

Oral delivery of nanomedicine for genetic kidney disease.

Chronic and genetic kidney diseases such as autosomal dominant polycystic kidney disease (ADPKD) have few therapeutic options, and clinical trials testing small molecule drugs have been unfavorable due to low kidney bioavailability and adverse side effects. Although nanoparticles can be designed to deliver drugs directly to the diseased site, there are no kidney-targeted nanomedicines clinically available, and most FDA-approved nanoparticles are administered intravenously which is not ideal for chronic diseases. To meet these challenges of chronic diseases, we developed a biomaterials-based strategy using chitosan particles (CP) for oral delivery of therapeutic, kidney-targeting peptide amphiphile micelles (KMs). We hypothesized that encapsuling KMs into CP would enhance the bioavailability of KMs upon oral administration given the high stability of chitosan in acidic conditions and mucoadhesive properties enabling absorption within the intestines. To test this, we evaluated the mechanism of KM access to the kidneys via intravital imaging and investigated the KM biodistribution in a porcine model. Next, we loaded KMs carrying the ADPKD drug metformin into CP (KM-CP-met) and measured in vitro therapeutic effect. Upon oral administration in vivo, KM-CP-met showed significantly greater bioavailability and accumulation in the kidneys as compared to KM only or free drug. As such, KM-CP-met treatment in ADPKD mice (Pkd1fl/fl;Pax8-rtTA;Tet-O-Cre which develops the disease over 120 days and mimics the slow development of ADPKD) showed enhanced therapeutic efficacy without affecting safety despite repeated treatment. Herein, we demonstrate the potential of KM-CP as a nanomedicine strategy for oral delivery for the long-term treatment of chronic kidney diseases.

Oral delivery of metformin by chitosan nanoparticles for polycystic kidney disease.

Nanoparticle drug delivery has many advantages over small molecule therapeutics, including reducing off-target side effects and increasing drug potency. However, many nanoparticles are administered parenterally, which is challenging for chronic diseases such as polycystic kidney disease (PKD), the most common hereditary disease worldwide in which patients need continuous treatment over decades. To address this clinical need, we present the development of nanoparticles synthesized from chitosan, a widely available polymer chosen for its ability to improve oral bioavailability. Specifically, we optimized the synthesis parameters of chitosan nanoparticles and demonstrate mucoadhesion and permeation across an intestinal barrier model in vitro. Furthermore, when administered orally to mice, ex vivo imaging of rhodamine-loaded chitosan nanoparticles showed significantly higher accumulation in the intestines compared to the free model drug, as well as 1.3 times higher serum area under the curve (AUC), demonstrating controlled release and improved serum delivery over 24 h. To test its utility for chronic diseases such as PKD, we loaded the candidate PKD drug, metformin, into chitosan nanoparticles, and upon oral administration to a PKD murine model (Pkd1fl/fl;Pax8-rtTA;Tet-O cre), a lower cyst burden was observed compared to free metformin, and was well tolerated upon repeated dosages. Blood urea nitrogen (BUN) and creatinine levels were similar to untreated mice, demonstrating kidney and biocompatibility health. Our study builds upon previous chitosan-based drug delivery approaches, and demonstrates a novel, oral nanoformulation for PKD.

miR-145 micelles mitigate atherosclerosis by modulating vascular smooth muscle cell phenotype.

In atherosclerosis, resident vascular smooth muscle cells (VSMCs) in the blood vessels become highly plastic and undergo phenotypic switching from the quiescent, contractile phenotype to the migratory and proliferative, synthetic phenotype. Additionally, recent VSMC lineage-tracing mouse models of atherosclerosis have found that VSMCs transdifferentiate into macrophage-like and osteochondrogenic cells and make up to 70% of cells found in atherosclerotic plaques. Given VSMC phenotypic switching is regulated by microRNA-145 (miR-145), we hypothesized that nanoparticle-mediated delivery of miR-145 to VSMCs has the potential to mitigate atherosclerosis development by inhibiting plaque-propagating cell types derived from VSMCs. To test our hypothesis, we synthesized miR-145 micelles targeting the C-C chemokine receptor-2 (CCR2), which is highly expressed on synthetic VSMCs. When miR-145 micelles were incubated with human aortic VSMCs in vitro, >90% miR-145 micelles escaped the lysosomal pathway in 4 hours and released the miR cargo under cytosolic levels of glutathione, an endogenous reducing agent. As such, miR-145 micelles rescued atheroprotective contractile markers, myocardin, α-SMA, and calponin, in synthetic VSMCs in vitro. In early-stage atherosclerotic ApoE-/- mice, one dose of miR-145 micelles prevented lesion growth by 49% and sustained an increased level of miR-145 expression after 2 weeks post-treatment. Additionally, miR-145 micelles inhibited 35% and 43% plaque growth compared to free miR-145 and PBS, respectively, in mid-stage atherosclerotic ApoE-/- mice. Collectively, we present a novel therapeutic strategy and cell target for atherosclerosis, and present miR-145 micelles as a viable nanotherapeutic that can intervene atherosclerosis progression at both early and later stages of disease.

CCR2-targeted micelles for anti-cancer peptide delivery and immune stimulation.

Signaling between the CC chemokine receptor 2 (CCR2) with its ligand, monocyte chemoattractant protein-1 (MCP-1) promotes cancer progression by directly stimulating tumor cell proliferation and downregulating the expression of apoptotic proteins. Additionally, the MCP-1/CCR2 signaling axis drives the migration of circulating monocytes into the tumor microenvironment, where they mature into tumor-associated macrophages (TAMs) that promote disease progression through induction of angiogenesis, tissue remodeling, and suppression of the cytotoxic T lymphocyte (CTL) response. In order to simultaneously disrupt MCP-1/CCR2 signaling and target CCR2-expressing cancer cells for drug delivery, KLAK-MCP-1 micelles consisting of a CCR2-targeting peptide sequence (MCP-1 peptide) and the apoptotic KLAKLAK peptide were synthesized. In vitro, KLAK-MCP-1 micelles were observed to bind and induce cytotoxicity to cancer cells through interaction with CCR2. In vivo, KLAK-MCP-1 micelles inhibited tumor growth (34 ± 11%) in a subcutaneous B16F10 murine melanoma model despite minimal tumor accumulation upon intravenous injection. Tumors treated with KLAK-MCP1 demonstrated reduced intratumor CCR2 expression and altered infiltration of TAMs and CTLs as evidenced by immunohistochemical and flow cytometric analysis. These studies highlight the potential application of CCR2-targeted nanotherapeutic micelles in cancer treatment.

In vivo tissue engineering of an adipose tissue flap using fat grafts and Adipogel.

For decades, plastic surgeons have spent considerable effort exploring anatomical regions for free flap design. More recently, tissue-engineering approaches have been utilised in an attempt to grow transplantable tissue flaps in vivo. The aim of this study was to engineer a fat flap with a vascular pedicle by combining autologous fat grafts and a novel acellular hydrogel (Adipogel) in an established tissue-engineering model comprising a chamber and blood vessel loop. An arteriovenous loop was created in the rat groin from the femoral vessels and positioned inside a perforated polycarbonate chamber. In Group 1, the chamber contained minced, centrifuged autologous fat; in Group 2, Adipogel was added to the graft; and in Group 3, Adipogel alone was used. Constructs were histologically examined at 6 and 12 weeks. In all groups, new tissue was generated. Adipocytes, although appearing viable in the graft at the time of insertion, were predominantly nonviable at 6 weeks. However, by 12 weeks, new fat had formed in all groups and was significantly greater in the combined fat/Adipogel group. No significant difference was seen in final construct total volume or construct neovascularisation between the groups. This study demonstrated that a pedicled adipose flap can be generated in rats by combining a blood vessel loop, an adipogenic hydrogel, and a lipoaspirate equivalent. Success appears to be based on adipogenesis rather than on adipocyte survival, and consistent with our previous work, this adipogenesis occurred subsequent to graft death and remodelling. The regenerative process was significantly enhanced in the presence of Adipogel.

Collagenase-Cleavable Peptide Amphiphile Micelles as a Novel Theranostic Strategy in Atherosclerosis.

Atherosclerosis is an inflammatory disease characterized by plaques that can cause sudden myocardial infarction upon rupture. Such rupture-prone plaques have thin fibrous caps due to collagenase degradation, and a noninvasive diagnostic tool and targeted therapy that can identify and treat vulnerable plaques and may inhibit the onset of acute cardiac events. Toward this goal, monocyte-binding, collagenase-inhibiting, and gadolinium-modified peptide amphiphile micelles (MCG PAMs) are developed. Monocyte chemoattractant protein-1 (MCP-1) binds to C-C chemokine receptor-2 expressed on pathological cell types present within plaques. Through the peptide binding motif of MCP-1, MCG PAMs bind to monocytes and vascular smooth muscle cells in vitro. Moreover, using magnetic resonance imaging, MCG PAMs show enhanced targeting and successful detection of plaques in diseased mice in vivo and act as contrast agents for molecular imaging. Through the collagenase-cleaving peptide sequence of collagen [VPMS-MRGG], MCG PAMs can compete for collagenases that degrade the fibrous cap of plaques, providing therapy. MCG PAM-treated mice show increased fibrous cap thickness by 61% and 113% histologically compared to nontargeting micelle- or PBS-treated mice (p = 0.0075 and 0.001, respectively). Overall, this novel multimodal nanoparticle offers new theranostic opportunities for noninvasive diagnosis and treatment of atherosclerotic plaques.

The clinical phenotype of mosaicism for genome-wide paternal uniparental disomy: two new reports.

Recently, mosaicism for genome-wide paternal uniparental disomy (patUPD), attributed to androgenetic/biparental mosaicism, has been shown to underlie placental mesenchymal dysplasia (PMD), a distinctive cystic placental phenotype. Manifestations of Beckwith-Wiedemann syndrome (BWS) have been observed in approximately one-third of fetuses or liveborn infants from pregnancies complicated by PMD. There are very few reports describing liveborn individuals with proven mosaicism for genome-wide patUPD in somatic tissues. We report two further children with complex phenotypes including some findings of BWS, congenital hyperinsulinemic hypoglycemia, prolonged feeding difficulty and failure to thrive in infancy. The first developed short stature, bilateral pheochromocytomas and progressive arterial stenoses, and the second had congenital adrenal cysts, and later developed hepatoblastoma and patchy hyperpigmentation. Leukocyte DNA methylation studies of KCNQ1OT1/LIT1 and H19 loci (11p15.5) showed almost complete loss of maternal methylation (LOM) in patient 1 and partial LOM in patient 2. Microsatellite marker panels showed whole chromosome 11 patUPD. SNP array studies in both were consistent with mosaic genome-wide patUPD in leukocytes, while fibroblast DNA in Patient 1 showed biparental inheritance. This report further illustrates the clinical consequences of mosaicism for genome-wide patUPD, which results in complex and variable phenotypes. Studies for genome-wide UPD should be considered in individuals with atypical UPD phenotypes.

Fate of Free Fat Grafts with or without Adipogenic Adjuncts to Enhance Graft Outcomes.

BACKGROUND: Free fat grafting is popular, but it is still unclear how it works. Although focusing on graft survival seems an obvious direction for improving clinical results, the authors' research suggests that long-term volume retention is in part attributable to new fat regeneration. Measures to facilitate adipogenesis may therefore be equally important. METHODS: To investigate the relative roles of survival and regeneration of fat grafts, the authors measured the fate of human lipoaspirate implanted into the scalps of immunodeficient mice, with and without stromal vascular fraction and a porcine extracellular matrix (Adipogel). Specifically, the authors were interested in volume retention, and the composition of implanted or regenerated tissue at 6 and 12 weeks. RESULTS: Free fat grafts exhibited poor volume retention and survival. Almost all of the injected human adipocytes died, but new mouse fat formed peripheral to the encapsulated fat graft. Adipogel and stromal vascular fraction improved proliferation of murine fat and human vasculature. Human CD34 stromal cells were present but only in the periphery, and there was no evidence that these cells differentiated into adipocytes. CONCLUSIONS: In the authors' model, most of the implanted tissue died, but unresorbed dead fat accounted substantially for the long-term, reduced volume. A layer of host-derived, regenerated adipose tissue was present at the periphery. This regeneration may be driven by the presence of dying fat, and it was enhanced by addition of the authors' adipogenic adjuncts. Future research should perhaps focus not only on improving graft survival but also on enhancing the adipogenic environment conducive to fat regeneration.

Melatonin promotes survival of nonvascularized fat grafts and enhances the viability and migration of human adipose-derived stem cells via down-regulation of acute inflammatory cytokines.

Nonvascularized fat grafting is a valuable technique for soft tissue reconstruction but poor survival of fat in the host environment remains a problem. A process known as cell-assisted transfer is used to enhance fat graft retention by adding stromal vascular fraction, an adipose-derived stem cell (ASC) rich content to lipoaspirate. We have recently shown that the use of melatonin, a reactive oxygen species scavenger, protects human ASCs from hydrogen peroxide-induced oxidative stress and cell death in vitro but its role as a pharmacological adjunct in clinical fat grafting has not been studied. Herein, the effect of melatonin was examined on human ASCs in vitro using survival and functional assays including the MTT assay, CellTox Green assay, monolayer scratch assay as well as a human cytokine chemoluminescence, and tumour necrosis factor-α assay. Further, the effect of melatonin-treated fat grafts was tested in vivo with a murine model. Haematoxylin and eosin staining, perilipin and CD31 immunostaining were performed with morphometric analysis of adipose tissue. The results demonstrate that, in vitro, the addition of melatonin to ASCs significantly improved their cell-viability, promoted cell migration and preserved membrane integrity as compared to controls. In addition, it induced a potent anti-inflammatory response by downregulating acute inflammatory cytokines particularly tumour necrosis factor-α. For the first time, it is demonstrated in vivo that melatonin enhances fat graft volume retention by reducing inflammation and increasing the percentage of adipose volume within fat grafts with comparable volumes to that of cell-assisted lipotransfer. Based on these novel findings, melatonin may be a useful pharmacological adjunct in clinical fat grafting.

Synthesis of Monocyte-targeting Peptide Amphiphile Micelles for Imaging of Atherosclerosis.

Atherosclerosis is a major contributor to cardiovascular disease, the leading cause of death worldwide, which claims 17.3 million lives annually. Atherosclerosis is also the leading cause of sudden death and myocardial infarction, instigated by unstable plaques that rupture and occlude the blood vessel without warning. Current imaging modalities cannot differentiate between stable and unstable plaques that rupture. Peptide amphiphiles micelles (PAMs) can overcome this drawback as they can be modified with a variety of targeting moieties that bind specifically to diseased tissue. Monocytes have been shown to be early markers of atherosclerosis, while large accumulation of monocytes is associated with plaques prone to rupture. Hence, nanoparticles that can target monocytes can be used to discriminate different stages of atherosclerosis. To that end, here, we describe a protocol for the preparation of monocyte-targeting PAMs (monocyte chemoattractant protein-1 (MCP-1) PAMs). MCP-1 PAMs are self-assembled through synthesis under mild conditions to form nanoparticles of 15 nm in diameter with near neutral surface charge. In vitro, PAMs were found to be biocompatible and had a high binding affinity for monocytes. The methods described herein show promise for a wide range of applications in atherosclerosis as well as other inflammatory diseases.

An adipogenic gel for surgical reconstruction of the subcutaneous fat layer in a rat model.

'Off-the-shelf' tissue-engineered skin alternatives for epidermal and dermal skin layers are available; however, no such alternative for the subdermal fat layer exists. Without this well-vascularized layer, skin graft take is variable and grafts may have reduced mobility, contracture and contour defects. In this study a novel adipose-derived acellular matrix (Adipogel) was investigated for its properties to generate subdermal fat in a rat model. In a dorsal thoracic site, a 1 × 1 cm Adipogel implant was inserted within a subdermal fat layer defect. In a dorsal lumbar site, an Adipogel implant was inserted in a subfascial pocket. Contralateral control defects remained empty. At 8 weeks wound/implant sites were evaluated histologically, immunohistochemically and morphometrically. Identifiable thoracic Adipogel implants lost volume in vivo over 8 weeks. Neovascularization and adipogenesis were evident within implants and adipocyte percentage volume was 33.07 ± 6.55% (mean ± SEM). A comparison of entire cross-sections of thoracic wounds demonstrated a significant increase in total wound fat in Adipogel-implanted wounds (37.19 ± 4.48%, mean ± SEM) compared to control (16.53 ± 4.60%; p = 0.0092), indicating that some Adipogel had been completely converted to normal fat. At the lumbar site, Adipogel also lost volume, appearing flattened, although fat generation and angiogenesis occurred. At both sites macrophage infiltration was mild, whilst many infiltrating cells were PDGFRß-positive mesenchymal cells. Adipogel is adipogenic and angiogenic and is a promising candidate for subcutaneous fat regeneration; it has the potential to be a valuable adjunct to wound-healing therapy and reconstructive surgery practice. Copyright © 2015 John Wiley & Sons, Ltd.

A Streamlined Method for the Preparation of Growth Factor-enriched Thermosensitive Hydrogels from Soft Tissue.

Hydrogels are an ideal medium for the expansion of cells in three dimensions. The ability to induce cell expansion and differentiation in a controlled manner is a key goal in tissue engineering. Here we describe a detailed method for producing hydrogels from soft tissues with an emphasis on adipose tissue. In this method, soluble, extractable proteins are recovered from the tissue and stored while the remaining insoluble tissue is processed and solubilised. Once the tissue has been sufficiently solubilised, the extracted proteins are added. The resulting product is a thermosensitive hydrogel with proteins representative of the native tissue. This method addresses common issues encountered when working with some biomaterials, such as high lipid content, DNA contamination, and finding an appropriate sterilisation method. Although the focus of this article is on adipose tissue, using this method we have produced hydrogels from other soft tissues including muscle, liver, and cardiac tissue.

Targeting cell adhesion molecules with nanoparticles using in vivo and flow-based in vitro models of atherosclerosis.

Atherosclerosis is a leading cause of death worldwide; in addition to lipid dysfunction, chronic arterial wall inflammation is a key component of atherosclerosis. Techniques that target cell adhesion molecules, which are overexpressed during inflammation, are effective methods to detect and treat atherosclerosis. Specifically, research groups have identified vascular cell adhesion molecule-1, intercellular adhesion molecule-1, platelet endothelial cell adhesion molecule, and selectins (E-selectin and P-selectin) as correlated to atherogenesis. In this review, we discuss recent strategies both in vivo and in vitro that target cell adhesion molecules. First, we discuss peptide-based and antibody (Ab)-based nanoparticles utilized in vivo for diagnostic, therapeutic, and theranostic applications. Second, we discuss flow-based in vitro models that serve to reduce the traditional disadvantages of in vivo studies such as variability, time to develop the disease, and ethical burden, but preserve physiological relevance. The knowledge gained from these targeting studies can be translated into clinical solutions for improved detection, prevention, and treatment of atherosclerosis. Impact statement As atherosclerosis remains the leading cause of death, there is an urgent need to develop better tools for treatment of the disease. The ability to improve current treatments relies on enhancing the accuracy of in vitro and in vivo atherosclerotic models. While in vivo models provide all the relevant testing parameters, variability between animals and among models used is a barrier to reproducible results and comparability of NP efficacy. In vitro cultures isolate cells into microenvironments that fail to take into account flow separation and shear stress, which are characteristics of atherosclerotic lesions. Flow-based in vitro models provide more physiologically relevant platforms, bridging the gap between in vivo and 2D in vitro models. This is the first review that presents recent advances regarding endothelial cell-targeting using adhesion molecules in light of in vivo and flow-based in vitro models, providing insights for future development of optimal strategies against atherosclerosis.

Protein Mimetic and Anticancer Properties of Monocyte-Targeting Peptide Amphiphile Micelles.

Monocyte chemoattractant protein-1 (MCP-1) stimulates the migration of monocytes to inflammatory sites, leading to the progression of many diseases. Recently, we described a monocyte-targeting peptide amphiphile micelle (MCP-1 PAM) incorporated with the chemokine receptor CCR2 binding motif of MCP-1, which has a high affinity for monocytes in atherosclerotic plaques. We further report here the biomimetic components of MCP-1 PAMs and the influence of the nanoparticle upon binding to monocytes. We report that MCP-1 PAMs have enhanced secondary structure compared to the MCP-1 peptide. As a result, MCP-1 PAMs displayed improved binding and chemoattractant properties to monocytes, which upregulated the inflammatory signaling pathways responsible for monocyte migration. Interestingly, when MCP-1 PAMs were incubated in the presence of prostate cancer cells in vitro, the particle displayed anticancer efficacy by reducing CCR2 expression. Given that monocytes play an important role in tumor cell migration and invasion, our results demonstrate that PAMs can improve the native biofunctional properties of the peptide and may be used as an effective inhibitor to prevent chemokine-receptor interactions that promote disease progression.