Transplantable human motor networks as a neuron-directed strategy for spinal cord injury

To repair neural circuitry following spinal cord injury (SCI), neural stem cell (NSC) transplantation has held a primary focus; however, stochastic outcomes generate challenges driven in part by NSC differentiation and tumor formation. The recent ability to generate regionally specific neurons and their support cells now allows consideration of directed therapeutic approaches with pre-differentiated and networked spinal neural cells. Here, we form encapsulated, transplantable neuronal networks of regionally matched cervical spinal motor neurons, interneurons, and oligodendrocyte progenitor cells derived through trunk-biased neuromesodermal progenitors. We direct neurite formation in alginate-based neural ribbons to generate electrically active, synaptically connected networks, characterized by electrophysiology and calcium imaging before transplantation into rodent models of contused SCI for evaluation at 10-day and 6-week timepoints. The in vivo analyses demonstrate viability and retention of interconnected synaptic networks that readily integrate with the host parenchyma to advance goals of transplantable neural circuitry for SCI treatment

Predicting the growth of glioblastoma multiforme spheroids using a multiphase porous media model

Tumor spheroids constitute an effective in vitro tool to investigate the avascular stage of tumor growth. These three-dimensional cell aggregates reproduce the nutrient and proliferation gradients found in the early stages of cancer and can be grown with a strict control of their environmental conditions. In the last years, new experimental techniques have been developed to determine the effect of mechanical stress on the growth of tumor spheroids. These studies report a reduction in cell proliferation as a function of increasingly applied stress on the surface of the spheroids. This work presents a specialization for tumor spheroid growth of a previous more general multiphase model. The equations of the model are derived in the framework of porous media theory, and constitutive relations for the mass transfer terms and the stress are formulated on the basis of experimental observations. A set of experiments is performed, investigating the growth of U-87MG spheroids both freely growing in the culture medium and subjected to an external mechanical pressure induced by a Dextran solution. The growth curves of the model are compared to the experimental data, with good agreement for both the experimental settings. A new mathematical law regulating the inhibitory effect of mechanical compression on cancer cell proliferation is presented at the end of the paper. This new law is validated against experimental data and provides better results compared to other expressions in the literature

A biphasic model for avascular tumor growth and drug response

Tumor spheroids provide an effective in vitro tool to study the early stages of cancer growth. The nutrient and proliferation gradients typical of the avascular stage of tumor development can be reproduced in the laboratory, with a strict control of the environmental conditions. Moreover, current techniques allow to tune the mechanical milieu in which the spheroids are immersed, and evaluate the effects of mechanical stress on tumor development. Remarkably, several studies report a reduction of cell proliferation as a function of increasingly applied stress on the surface of the spheroids. Recently, a computational model based on porous media theory has been proposed to predict tumor growth and its interaction with the host tissue. Inspired by this work, here we report on a specialization of the original model, adapted for tumor spheroids. Starting from standard balance equations for a multiphase system, we close the model with the aid of constitutive relations that are formulated on the basis of experimental observations. In particular, we introduce mathematical expressions describing the mass exchange terms between the different components of the system, and enforce a constitutive relation for the stresses that accounts for the microscopic interactions between the cancer cells. Also, we study the spatiotemporal evolution of a nutrient and of a chemotherapeutic agent over the tumor domain, evaluating their coupled effects on cell proliferation. The spatial discretization of the coupled problem is carried out via the Finite Element Method, and the resulting system is solved with an implicit scheme in COMSOL Multiphysics. A set of experiments is performed to validate the model, investigating the growth of U-87MG spheroids both freely growing in the culture medium and subject to an externally controlled mechanical pressure. Model results are compared to experimental data, showing a good agreement for both the experimental settings. We present a new mathematical law describing the inhibitory effect of mechanical compression on cell proliferation. The new law is validated against the experimental data, providing better results when compared to other expressions in literature

Assembly of iron oxide nanocubes for enhanced cancer hyperthermia and magnetic resonance imaging

Multiple formulations of iron oxide nanoparticles (IONPs) have been proposed for enhancing contrast in magnetic resonance imaging (MRI) and for increasing efficacy in thermal ablation therapies. However, insufficient accumulation at the disease site and low magnetic performance hamper the clinical application of IONPs. Here, 20 nm iron oxide nanocubes were assembled into larger nanoconstructs externally stabilized by a serum albumin coating. The resulting assemblies of nanocubes (ANCs) had an average diameter of 100 nm and exhibited transverse relaxivity (r2= 678.9 \uc2\ub1 29.0 mM\ue2\u80\u921\uc2\ub7s\ue2\u80\u921at 1.41 T) and heating efficiency (specific absorption rate of 109.8 \uc2\ub1 12.8 W\uc2\ub7g\ue2\u80\u921at 512 kHz and 10 kA\uc2\ub7m\ue2\u80\u921). In mice bearing glioblastoma multiforme tumors, Cy5.5-labeled ANCs allowed visualization of malignant masses via both near infrared fluorescent and magnetic resonance imaging. Also, upon systemic administration of ANCs (5 mgFe\uc2\ub7kg\ue2\u80\u921), 30 min of daily exposure to alternating magnetic fields for three consecutive days was sufficient to halt tumor progression. This study demonstrates that intravascular administration of ANCs can effectively visualize and treat neoplastic masses

Geometrical confinement of Gd(DOTA) molecules within mesoporous silicon nanoconstructs for MR imaging of cancer

Porous silicon has been used for the delivery of therapeutic and imaging agents in several biomedical applications. Here, mesoporous silicon nanoconstructs (SiMPs) with a discoidal shape and a sub-micrometer size (1,000 × 400 nm) have been conjugated with gadolinium-tetraazacyclododecane tetraacetic acid Gd(DOTA) molecules and proposed as contrast agents for Magnetic Resonance Imaging. The surface of the SiMPs with different porosities – small pore (SP: ~ 5 nm) and huge pore (HP: ~ 40 nm) – and of bulk, non-porous silica beads (1,000 nm in diameter) have been modified with covalently attached (3-aminopropyl)triethoxysilane (APTES) groups, conjugated with DOTA molecules, and reacted with an aqueous solution of GdCl3. The resulting Gd(DOTA) molecules confined within the small pores of the Gd-SiMPs achieve longitudinal relaxivities r1 of ~ 17 (mM·s)−1, which is 4 times greater than for free Gd(DOTA). This enhancement is ascribed to the confinement and stable chelation of Gd(DOTA) molecules within the SiMP mesoporous matrix. The resulting nanoconstructs possess no cytotoxicity and accumulate in ovarian tumors up to 2% of the injected dose per gram tissue, upon tail vein injection. All together this data suggests that Gd-SiMPs could be efficiently used for MR vascular imaging in cancer and other diseases

Synthesis of Multifunctional Magnetic NanoFlakes for Magnetic Resonance Imaging, Hyperthermia, and Targeting.

Iron oxide nanoparticles (IOs) are intrinsically theranostic agents that could be used for magnetic resonance imaging (MRI) and local hyperthermia or tissue thermal ablation. Yet, effective hyperthermia and high MR contrast have not been demonstrated within the same nanoparticle configuration. Here, magnetic nanoconstructs are obtained by confining multiple, ∼ 20 nm nanocubes (NCs) within a deoxy-chitosan core. The resulting nanoconstructsmagnetic nanoflakes (MNFs)exhibit a hydrodynamic diameter of 156 ± 3.6 nm, with a polydispersity index of ∼0.2, and are stable in PBS up to 7 days. Upon exposure to an alternating magnetic field of 512 kHz and 10 kA m^–1, MNFs provide a specific absorption rate (SAR) of ∼75 W g_Fe^–1, which is 4–15 times larger than that measured for conventional IOs. Moreover, the same nanoconstructs provide a remarkably high transverse relaxivity of ∼500 (mM s)⁻¹, at 1.41T. MNFs represent a first step toward the realization of nanoconstructs with superior relaxometric and ablation properties for more effective theranostics

Rapamycin reduces clinical signs and neuropathic pain in a chronic model of experimental autoimmune encephalomyelitis.

Current treatments used in Multiple Sclerosis (MS) are partly effective in the early stages of the disease but display very limited benefits in patients affected by progressive MS. One possible explanation is that these therapies are unable to target the inflammatory component most active during the progressive phase of the disease, and compartmentalized behind the blood-brain barrier. Our findings show that Rapamycin ameliorates clinical and histological signs of chronic EAE when administered during ongoing disease. Moreover, Rapamycin significantly reduced the hyperalgesia observed before clinical development of EAE which, in turn, is completely abolished by the administration of the drug

Pro-inflammatory-activated glioma cells induce a switch in microglial polarization and activation status, from a predominant M2b phenotype to a mixture of M1 and M2a/b polarized cells

Malignant gliomas are primary brain tumors characterized by morphological and genetic complexities, as well as diffuse infiltration into normal brain parenchyma. Within gliomas, microglia/macrophages represent the largest tumor-infiltrating cell population, contributing by at least one third to total tumor mass. Bi-directional interactions between glioma cells and microglia may therefore play an important role on tumor growth and biology. In the present study, we have characterized the influence of glioma soluble factors on microglial function, comparing the effects of media harvested under basal conditions to those of media obtained after inducing a proinflammatory activation state in glioma cells. We found that microglial cells undergo a different pattern of activation depending on the stimulus; in the presence of activated glioma-derived factors, i.e. a condition mimicking the late stage of pathology, microglia presents as a mixture of polarization phenotypes (M1 and M2a/b), with up-regulation of iNOS, ARG and IL-10. At variance, microglia exposed to basal glioma-derived factors, i.e. a condition resembling the early stage of pathology, shows a more specific pattern of activation, with increased M2b polarization status and up-regulation of IL-10 only. As far as viability and cell proliferation are concerned, both LI-CM and C-CM induce similar effects on microglial morphology. Finally, in human glioma tissue obtained from surgical resection of patients with IV grade glioblastoma, we detected a significant amount of CD68 positive cells, which is a marker of macrophage/microglial phagocytic activity, suggesting that in vitro findings presented here might have a relevance in the human pathology as well

Soft Discoidal Polymeric Nanoconstructs Resist Macrophage Uptake and Enhance Vascular Targeting in Tumors

Most nanoparticles for biomedical applications originate from the self-assembling of individual constituents through molecular interactions and possess limited geometry control and stability. Here, 1000 × 400 nm discoidal polymeric nanoconstructs (DPNs) are demonstrated by mixing hydrophobic and hydrophilic polymers with lipid chains and curing the resulting paste directly within silicon templates. By changing the paste composition, soft- and rigid-DPNs (s- and r-DPNs) are synthesized exhibiting the same geometry, a moderately negative surface electrostatic charge (−14 mV), and different mechanical stiffness (∼1.3 and 15 kPa, respectively). Upon injection in mice bearing nonorthotopic brain or skin cancers, s-DPNs exhibit ∼24 h circulation half-life and accumulate up to ∼20% of the injected dose per gram tumor, detecting malignant masses as small as ∼0.1% the animal weight <i>via</i> PET imaging. This unprecedented behavior is ascribed to the unique combination of geometry, surface properties, and mechanical stiffness which minimizes s-DPN sequestration by the mononuclear phagocyte system. Our results could boost the interest in using less conventional delivery systems for cancer theranosis

Hierarchically structured magnetic nanoconstructs with enhanced relaxivity and cooperative tumor accumulation

Iron oxide nanoparticles are formidable multifunctional systems capable of contrast enhancement in magnetic resonance imaging, guidance under remote fields, heat generation, and biodegradation. Yet, this potential is underutilized in that each function manifests at different nanoparticle sizes. Here, sub-micrometer discoidal magnetic nanoconstructs are realized by confining 5 nm ultra-small super-paramagnetic iron oxide nanoparticles (USPIOs) within two different mesoporous structures, made out of silicon and polymers. These nanoconstructs exhibit transversal relaxivities up to \ue2\u89\u8810 times (r2\ue2\u89\u88 835 mm-1s-1) higher than conventional USPIOs and, under external magnetic fields, collectively cooperate to amplify tumor accumulation. The boost in r2relaxivity arises from the formation of mesoscopic USPIO clusters within the porous matrix, inducing a local reduction in water molecule mobility as demonstrated via molecular dynamics simulations. The cooperative accumulation under static magnetic field derives from the large amount of iron that can be loaded per nanoconstuct (up to \ue2\u89\u8865 fg) and the consequential generation of significant inter-particle magnetic dipole interactions. In tumor bearing mice, the silicon-based nanoconstructs provide MRI contrast enhancement at much smaller doses of iron (\ue2\u89\u880.5 mg of Fe kg-1animal) as compared to current practice. \uc2\ua9 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim