Nasal Delivery of Antioxidants by Cholesterol-incorporated Liposomes Extends the Neuroprotective Time Window in Cerebral Ischemia.

Antioxidants have the potential to prevent cerebral ischemia-reperfusion (IR)-associated secondary damage induced by reactive oxygen species (ROS); however, the short therapeutic time window of IR is a considerable obstacle. Nano-sized nasal delivery systems provide an effective means of delivering drugs through the BBB, but few such systems have been developed to extend the treatment time window in IR. In this work, a nanosized nasal delivery system for antioxidants was found to have the potential to extend the neuroprotective time window. The authors chose to use the antioxidant C-phycocyanin (C-Pc) to design a neuroprotective liposome with a long life, controllable release, and high neuronal uptake rate. Liposomes formulated with various cholesterol to phospholipid ratios were assessed thermodynamically, kinetically, and biologically. Thermodynamically stable, monodispersive, and release-controllable C-Pc liposomes were more effectively taken up by Neuro2a cells than free C-Pc and were biocompatible, maintaining the anti-oxidative properties of C-Pc. When optimal C-Pc liposomes were administered to middle cerebral artery occlusion (MCAO) rats 2 h after onset, infarct sizes were smaller and behavioral activities improved compared with the same metrics in free C-Pc-treated rats. Liposomal delivery still reduced infarct sizes and improved behavioral activity 6 h after onset, whereas free C-Pc did not.

Assessment of Neuronal Cell-Based Cytotoxicity of Neurotoxins from an Estuarine Nemertean in the Han River Estuary.

A heteronemertean, Yininemertes pratensis, was collected in Han River Estuary, South Korea. This estuarine nemertean has been known by the local fishermen for harmful effects to the glass eels, juveniles of Japanese eel Anguilla japonica, migrating to fresh water. The present study confirmed the neurotoxic effects of this heteronemertean ribbon worm at the cellular level. Derivative types of neurotoxic tetrodotoxin (TTX), 5,11-dideoxy TTX (m/z 288) and 11-norTTX-6(S)-01 (m/z 305.97), were identified through HPLC and MALDI-TOF MS. However, significant neurotoxicity was confirmed in the fraction containing an undefined molecule corresponding to the 291.1 (m/z) peak, when tested in rat primary astrocytes and dorsal ganglion cells. This study is the first to report neurotoxins of the estuarine nemertean, fairly abundant in the Han River estuary, and suggests the long-term monitoring of population dynamics and surveillance of the toxicity in this river estuary.

Thermodynamic Insights and Conceptual Design of Skin-Sensitive Chitosan Coated Ceramide/PLGA Nanodrug for Regeneration of Stratum Corneum on Atopic Dermatitis.

Atopic dermatitis (AD) is a complex skin disease primarily characterized by psoriasis of the stratum corneum. AD drugs have usually been used in acidic and hydrophilic solvents to supply moisture and prevent lipid defects. Ceramide is a typical treatment agent to regenerate the stratum corneum and relieve symptoms of AD. However, ceramide has limitation on direct use for skin because of its low dispersion properties in hydrophilic phase and side effects at excessive treatment. In this study, ceramide imbedded PLGA nanoparticles were developed with chitosan coating (Chi-PLGA/Cer) to overcome this problem. The chitosan coating enhanced initial adherence to the skin and prevented the initial burst of ceramide, but was degraded by the weakly acidic nature of skin, resulting in controlled release of ceramide with additional driving force of the squeezed PLGA nanoparticles. Additionally, the coating kinetics of chitosan were controlled by manipulating the reaction conditions and then mathematically modeled. The Chi-PLGA/Cer was not found to be cytotoxic and ceramide release was controlled by pH, temperature, and chitosan coating. Finally, Chi-PLGA/Cer was demonstrated to be effective at stratum corneum regeneration in a rat AD model. Overall, the results presented herein indicated that Chi-PLGA/Cer is a novel nanodrug for treatment of AD.

Assessment of C-phycocyanin effect on astrocytes-mediated neuroprotection against oxidative brain injury using 2D and 3D astrocyte tissue model.

Drugs are currently being developed to attenuate oxidative stress as a treatment for brain injuries. C-phycocyanin (C-Pc) is an antioxidant protein of green microalgae known to exert neuroprotective effects against oxidative brain injury. Astrocytes, which compose many portions of the brain, exert various functions to overcome oxidative stress; however, little is known about how C-Pc mediates the antioxidative effects of astrocytes. In this study, we revealed that C-Pc intranasal administration to the middle cerebral artery occlusion (MCAO) rats ensures neuroprotection of ischemic brain by reducing infarct size and improving behavioral deficits. C-Pc also enhanced viability and proliferation but attenuated apoptosis and reactive oxygen species (ROS) of oxidized astrocytes, without cytotoxicity to normal astrocytes and neurons. To elucidate how C-Pc leads astrocytes to enhance neuroprotection and repair of ischemia brain, we firstly developed 3D oxidized astrocyte model. C-Pc had astrocytes upregulate antioxidant enzymes such as SOD and catalase and neurotrophic factors BDNF and NGF, while alleviating inflammatory factors IL-6 and IL-1ß and glial scar. Additionally, C-Pc improved viability of 3D oxidized neurons. In summary, C-Pc was concluded to activate oxidized astrocytes to protect and repair the ischemic brain with the combinatorial effects of improved antioxidative, neurotrophic, and anti-inflammatory mechanisms.

Regulation of astrocyte activity via control over stiffness of cellulose acetate electrospun nanofiber.

Astrocytes are involved in neuron protection following central nervous system (CNS) injury; accordingly, engineered astrocytes have been investigated for their usefulness in cell therapy for CNS injury. Nanofibers have attracted a great deal of attention in neural tissue engineering, but their mechanical properties greatly influence physiology. Cellulose acetate (CA) has been studied for use in scaffolds owing to its biocompatibility, biodegradability, and good thermal stability. In this study, stiffness of CA nanofibers controlled by heat treatment was shown to regulate astrocyte activity. Adhesion and viability increased in culture as substrate became stiffer but showed saturation at greater than 2 MPa of tensile strength. Astrocytes became more active in terms of increasing intermediate filament glial fibrillary acidic protein (GFAP). The results of this study demonstrate the effects of stiffness alone on cellular behaviors in a three-dimensional culture and highlight the efficacy of heat-treated CA for astrocyte culture in that the simple treatment enables control of astrocyte activity.