Modulation of the intrinsic neuronal excitability by multifunctional liposomes tailored for the treatment of alzheimer’s disease

Purpose: Nanotechnologies turned out to be promising in the development of diagnostic and therapeutic approaches toward neurodegenerative disorders. However, only a very scant number of nanodevices until now proved to be effective on preclinical animal models. Although specific tests in vivo are available to assess the potential toxicity of these nanodevices on cognitive functions, those to evaluate their biosafety in vitro on neurons are still to be improved. Materials and methods: We utilized the patch-clamp technique on primary cultures of cortical neural cells isolated from neonatal rats, aiming to evaluate their electrical properties after the incubation with liposomes (mApoE-PA-LIPs), previously proved able to cross the blood\u2013brain barrier and to be effective on mouse models of Alzheimer\u2019s disease (AD), both in the absence and in the presence of \u3b2-amyloid peptide oligomers. Results: Data show a high degree of biocompatibility, evaluated by lactate dehydrogenase (LDH) release and MTT assay, and the lack of cellular internalization. After the incubation with mApoE-PA-LIPs, neuronal membranes show an increase in the input resistance (from 724.14\ub176 M\u3a9 in untreated population to 886.06\ub186 M\u3a9 in the treated one), a reduction in the rheobase current (from 29.6\ub13 to 24.2\ub13 pA in untreated and treated, respectively), and an increase of the firing frequency, consistent with an ultimate increase in intrinsic excitability. Data obtained after co-incubation of mApoE-PA-LIPs with \u3b2-amyloid peptide oligomers suggest a retention of liposome efficacy. Conclusion: These data suggest the ability of liposomes to modulate neuronal electrical properties and are compatible with the previously demonstrated amelioration of cognitive functions induced by treatment of AD mice with liposomes. We conclude that this electrophysiological approach could represent a useful tool for nanomedicine to evaluate the effect of nanoparticles on intrinsic neuronal excitability

New FTY720-docetaxel nanoparticle therapy overcomes FTY720-induced lymphopenia and inhibits metastatic breast tumour growth

Purpose: Combining molecular therapies with chemotherapy may offer an improved clinical outcome for chemoresistant tumours. Sphingosine-1-phosphate (S1P) receptor antagonist and sphingosine kinase 1 (SK1) inhibitor FTY720 (FTY) has promising anticancer properties, however, it causes systemic lymphopenia which impairs its use in cancer patients. In this study, we developed a nanoparticle (NP) combining docetaxel (DTX) and FTY for enhanced anticancer effect, targeted tumour delivery and reduced systemic toxicity. Methods: Docetaxel, FTY and glucosamine were covalently conjugated to poly(lactic-co-glycolic acid) (PLGA). NPs were characterised by dynamic light scattering and electron microscopy. The cellular uptake, cytotoxicity and in vivo antitumor efficacy of CNPs were evaluated. Results: We show for the first time that in triple negative breast cancer cells FTY provides chemosensitisation to DTX, allowing a four-fold reduction in the effective dose. We have encapsulated both drugs in PLGA complex NPs (CNPs), with narrow size distribution of ~ 100 nm and excellent cancer cell uptake providing sequential, sustained release of FTY and DTX. In triple negative breast cancer cells and mouse breast cancer models, CNPs had similar efficacy to systemic free therapies, but allowed an effective drug dose reduction. Application of CNPs has significantly reversed chemotherapy side effects such as weight loss, liver toxicity and, most notably, lymphopenia. Conclusions: We show for the first time the DTX chemosensitising effects of FTY in triple negative breast cancer. We further demonstrate that encapsulation of free drugs in CNPs can improve targeting, provide low off-target toxicity and most importantly reduce FTY-induced lymphopenia, offering potential therapeutic use of FTY in clinical cancer treatment

Decoupling the shape parameter to assess gold nanorod uptake by mammalian cells

The impact of nanoparticles (NPs) upon biological systems can be fundamentally associated with their physicochemical parameters. A further often-stated tenet is the importance of NP shape on rates of endocytosis. However, given the convoluted parameters concerning the NP–cell interaction, it is experimentally challenging to attribute any findings to shape alone. Herein we demonstrate that shape, below a certain limit, which is specific to nanomedicine, is not important for the endocytosis of spherocylinders by either epithelial or macrophage cells in vitro. Through a systematic approach, we reshaped a single batch of gold nanorods into different aspect ratios resulting in near-spheres and studied their cytotoxicity, (pro-)inflammatory status, and endocytosis/exocytosis. It was found that on a length scale of ∼10–90 nm and at aspect ratios less than 5, NP shape has little impact upon their entry into either macrophages or epithelial cells. Conversely, nanorods with an aspect ratio above 5 were preferentially endocytosed by epithelial cells, whereas there was a lack of shape dependent uptake following exposure to macrophages in vitro. These findings have implications both in the understanding of nanoparticle reshaping mechanisms, as well as in the future rational design of nanomaterials for biomedical applications

A fatal case of autumn crocus (Colchicum autumnale) poisoning in a heifer: confirmation by mass-spectrometric colchicine detection

A heifer developed severe signs of acute gastrointestinal irritation 48 hr after ingesting fresh leaves of Colchicum autumnale growing on a damp meadow. Confirmation of the suspected toxicosis was obtained by detecting colchicine in serum and urine using liquid chromatography coupled with tandem mass spectrometry using atmospheric pressure chemical ionization. Although the serum colchicine concentration had declined to an apparently nontoxic level of 2.4 ng/ml, a more prominent concentration (640 ng/ml) indicative of colchicine poisoning was detected in the urine. This finding is consistent with the known toxicokinetic properties of colchicine, whereby a large volume of distribution results in low circulating blood concentrations and prolonged urinary excretion

Plasma phytochemicals : mediators of CVD risk reduction and biomarkers of fruit and vegetable intake

This research is concerned with the analysis of data from two dietary intervention studies. The first study investigated the effects of acute ingestion of low-dose blackcurrant juice drink on the antioxidant capacity of plasma, acute measures of vascular reactivity and biomarkers of endothelial function: The second study was a randomized, controlled, dietary intervention study (FLAVURS) (n = 154) in which the test groups had sequential increases of 2,4 and 6 portions of high flavonoid or low flavonoid fruits and vegetables (F & V) every 6 weeks across an 18 week period. This thesis reports the dietary strategy to increase the amount and types of fruits and vegetables consumed by a free living population. Selected data from the study was used to develop an improved biomarker for F & V consumption, and data from the study was also used to investigate the association between plasma antioxidants and markers of vascular reactivity and endothelial function. The acute study showed that consumption of a 20% blackcurrant juice drink caused increases in plasma vitamin C (P=0.006), and urinary anthocyanins (P<O.OO1), Delphinidin-3-rutinoside and cyanidin-3-rutinoside were the main anthocyanins excreted in urine with delphinidin-3-glucoside also detected. However, consumption of the juice did not have a significant effect on vascular reactivity. Anthocyanins were present at low concentrations in the urine, and microbial metabolites of flavonoids were detected in plasma after juice consumption. Investigation of the data from the FLA VURS study at the final visit, when the difference between the control group and those consuming additional F & V was at a maximum, showed that a modified integrated plasma biomarker including plasma vitamin C, total carotenoids and FRAPvalues multiplied by factors to bring them into the same range gave a better correlation with F&V intake (r = 0.518, P < 0.001) than the individual biomarkers (r = 0.332, P < 0.001; r = 0.417, P < 0.001; r = 0.136 P = 0.099). However, the modified integrated plasma biomarker did not correlate sufficiently well with F&V intake to allow it to be used for determining intake. Analysis of the data from the final visit by the volunteers in the FLAVURS study also showed that plasma total carotenoid content was inversely correlated with systolic ambulatory blood pressure (ABP) during both waking and sleeping periods respectively (r = -0.231, P = 0.01; r = -0.228, P = 0.022). Both plasma lutein and β-cryptoxanthin were inversely correlated with systolic ABP during the waking period (r = -0.235; P = 0.008for lutein; r = -0.193, P = 0.031 for β-cryptoxanthin). β-Carotene was inversely correlated with systolic ABP during waking and sleeping periods respectively (r = -0.253, P = 0.005; r = -0.229, P = 0.023) and also with diastolic ABP during the waking period (r = -0.209, P = 0.022). Lycopene was found to be inversely correlated with both PWV (r = -0.192, P = 0.022) (Figure 5.5) and systolic ABP during both waking and sleeping periods (r = -0.225, P = 0.012; r = -0.235, P = 0.018 respectively). In contrast to the dietary antioxidants, plasma uric acid was found to correlate positively with both the systolic and diasystolic ABP during both waking and sleeping periods respectively (r = 0.392, P < 0.001; r = 0.342, P < 0.001 for waking periods, and r = 0.328, P = 0.001; r = 0.360, P < 0.001 for sleeping periods). This research has shown that an improved biomarker can be obtained by combining FRAP, plasma vitamin C and plasma carotenoid concentrations but the correlation is still not sufficiently good to predict F & V intake. Plasma phytochemicals and metabolites can be detected at low levels of intake of F & V or juices, but physiological effects are only evident at higher levels of intake. Literature evidence on the effects of carotenoids on blood pressure is strengthened by the observed association between plasma carotenoids and a reduction in blood pressure, but the effect is small. Also, the possible effect of lycopene on endothelial function has been identified.EThOS - Electronic Theses Online ServiceGBUnited Kingdo