1,721,049 research outputs found
NANOTECHNOLOGY IN BIOMEDICINE: quantum dots biodistribution, an in vivo and ex vivo study
No full textnanotechnology applications in biomedicin
hyperthermic nanoparticles to trigger adipolysis
Full text linkHere, we demonstrate that, under appropriate administration conditions, polyhedral iron oxide nanoparticles are efficiently and safely taken up by 3T3 cell linederived adipocytes (3T3 adipocytes) in vitro. Since these nanoparticles proved to effectively produce heat when subjected to alternating magnetic field, 3T3 adipocytes were submitted to superparamagnetic iron oxide nanoparticles- mediated hyperthermia treatment (SMHT), with the aim of modulating their lipid content. Notably, the treatment resulted in a significant delipidation persisting for at least 24 h, and in the absence of cell death, damage or dedifferentiation. Interestingly, transcript expression of adipose triglyceride lipase (ATGL), a key gene involved in canonical lipolysis, was not modulated upon SMHT, suggesting the involvement of a novel/ alternative mechanism in the effective lipolysis observed. By applying the same experimental conditions successfully used for 3T3 adipocytes, SMHT was able to induce delipidation also in primary cultures of human adipose-derived adult stem cells. The success of this pioneering approach in vitro opens promising perspectives for the application of SMHT in vivo as an innovative safe and physiologically mild strateg
THERAPEUTIC NANOPRODUCTS: FROM BIOLOGY TO INNOVATIVE TECHNOLOGY Abstracts
No full textDuring last years, evidence has been provided on the involvement of obesity in the pathogenesis and aggravation of several life-threatening diseases. In this view, we set up an innovative protocol to induce a nanoparticle-mediated lipolysis in vitro by combining light and electron microscopy and biochemical approaches. Under appropriate administration conditions, 3T3-L1 mouse adipocytes proved to efficiently and safely internalize superparamagnetic iron oxide nanoparticles (SPIONs), which are able to produce heat when subjected to alternating magnetic field (1;2;3). Thus, 3T3-L1 adipocytes were submitted to SPIONs-mediated hyperthermia treatment (SMHT), with the aim of modulating their lipid content (4,5). The treatment resulted in a significant delipidation persisting for at least 24 h, in the absence of cell death, damage or dedifferentiation. Interestingly, some factors normally linked with lipolysis event or in lipid metabolism (6) were not modulated upon SMHT, suggesting the involvement of a novel/alternative mechanism in the lipolysis observed. Notably, the same SMHT was able to induce delipidation also in primary cultures of human adipose-derived adult stem cells. The success of this new approach in vitro opens promising perspectives for the application of SMHT in different biomedical fields. Next steps could be the use of SION on sperimental model of obesity to analyze different metabolic pathway that are activated by the SMHT and also the application of SMHT on a sperimental model of cancer in obesity subjects to study the crosstalk between adipose and tumor tissues
Caratterizzazione preclinica in vitro di nuovi inibitori non peptidomimetici della glutatione trasferasi P1-1
Full text linkGlutathione transferases (formerly glutathione S-transferases, GSTs) are a superfamily of enzymes involved in the glutathione (GSH)-dependend detoxification of a wide range of chemicals, including drugs. Moreover, certain members of this superfamily interact with and modulate the activity of protein kinases involved in key cellular processes, including proliferation and apoptosis [Ruzza et al., 2009]. Among them, GSTP1-1 is frequently overexpressed in a variety of human tumors, where it contributes to conferring resistance to different anticancer agents. In light of these observations, several GST inhibitors or GST-activated prodrugs have been investigated throughout the years; however, none of them has been approved for use as antitumor drug [Ruzza et al., 2009; Sau et al., 2010].
6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX) and its structural analogue MC3181 are promising anticancer agents with potent inhibitory activity towards GSTP1-1 [Ricci et al., 2005; Pasello et al., 2011; De Luca et al., 2014]. A first aim of this work was to evaluate the metabolic fate of these compounds in humans and in laboratory animal species. The metabolic stability of NBDHEX and MC3181 was assessed by high performance liquid chromatography (HPLC) or LC coupled to diode array detection and tandem mass spectrometry (LC-DAD-MS/MS), upon incubation of each drug with human, mouse or rat liver microsomes or cytosol as enzyme source. The reactions investigated were UDP-glucuronic acid (UDPGA)-dependent glucuronidation, reduced nicotinamide adenine dinucleotide phosphate (NADPH)-dependent microsomal oxidation, and oxidized nicotinamide adenine dinucleotide (NAD+)-dependent cytosolic oxidation.
Both NBDHEX and MC3181 underwent glucuronidation and microsomal NADPH-dependent oxidation in all of the investigated species. Moreover, NBDHEX, but not MC3181, underwent alcohol dehydrogenase-dependent oxidation in both human, rat and mouse cytosol.
The identity of NBDHEX glucuronide was confirmed by nuclear magnetic resonance analyses.
Finally, interspecies differences were identified in the glucuronidation of both compounds and in the cytosolic oxidation of NBDHEX, while sex-related differences were observed in the rate of glucuronidation of MC3181 as well as in the rate of cytosolic oxidation of NBDHEX.
Sulfasalazine (sulfasalazopyridine; SASP), a drug currently used to treat rheumatic and inflammatory bowel diseases, is a non-substrate inhibitor of various human GSTs, including GSTP1-1 [Ahmad et al., 1992]. Despite this, its poor oral bioavailability and metabolic instability (which is mainly linked to the presence of an azo group in its structure) hinder its use as an anticancer agent. In this work, 30 SASP analogues containing an imidazole ring in substitution of the azo group of SASP (i.e. salycylbenzoimidazole derivatives, EML), have been investigated as potential inhibitors of human GSTP1-1. Further structural modifications involved the sulfonamide as well as the aminosalicylic moiety of the drug.
Seven out of 30 of the salycylbenzoimidazole derivatives studied (i.e. EML340, EML277, EML259, EML337, EML357, EML279, and EML338) inhibited human placental GST (mostly GSTP1-1) conjugation activity more efficiently than the parent compound, SASP. Thus, the azo group seems to be not essential for inhibition of the enzyme activity.
Further enzyme inhibition assays carried out using human recombinant GST A1-1, M1-1 and P1-1, showed that EML337 displays a certain grade of selectivity for GSTP1-1, while EML340 and EML277 were highly selective towards GSTM1-1.
Finally, preliminary in vitro cytotoxicity assays indicate that the methyl esters EML259, EML337 and EML339 can interfere with the growth of A375 and SK-MEL 23 human melanoma cell lines
Imaging techniques in nanomedical research
No full textAbout twenty years ago, nanotechnology began to be applied to biomedical issues giving rise to the research field called nanomedicine. Thus, the study of the interactions between nanomaterials and the biological environment became of primary importance in order to design safe and effective nanoconstructs suitable for diagnostic and/or therapeutic purposes. Consequently, imaging techniques have increasingly been used in the production, characterisation and preclinical/clinical application of nanomedical tools. This work aims at making an overview of the microscopy and imaging techniques in vivo and in vitro in their application to nanomedical investigation, and to stress their contribution to this developing research field
Integrated microscopy and metabolomics to test an innovative fluid dynamic system for skin explants in vitro
Full text linkThe in vitro models are receiving growing attention in studies on skin permeation, penetration, and irritancy, especially for the preclinical development of new transcutaneous drugs. However, synthetic membranes or cell cultures are unable to effectively mimic the permeability and absorption features of the cutaneous barrier. The use of explanted skin samples maintained in a fluid dynamic environment would make it possible for an in vitro experimentation closer to in vivo physiological conditions. To this aim, in the present study, we have modified a bioreactor designed for cell culture to host explanted skin samples. The preservation of the skin was evaluated by combining light, transmission, and scanning electron microscopy, for the histo/cytological characterization, with nuclear magnetic resonance spectroscopy, for the identification in the culture medium of metabolites indicative of the functional state of the explants. Our morphological and metabolomics results demonstrated that fluid dynamic conditions ameliorate significantly the structural and functional preservation of skin explants in comparison with conventional culture conditions. Our in vitro system is, therefore, reliable to test novel therapeutic agents intended for transdermal administration in skin samples from biopsies or surgical materials, providing predictive information suitable for focused in vivo research and reducing animal experimentation
Spontaneous luminescence background in living Nu/Nu mice
No full textSpontaneous light emission from living animals can overcome the investigated light signals in small animal luminescence imaging. Despite autofluorescence emission is well studied the spontaneous luminescence background is less known and its importance is growing due to the new born imaging techniques like Cerenkov Luminescence Imaging and Radionuclide Luminescence Imaging in which faint sources are often involved. In order to investigate the spontaneous emission we studied the background luminescence in vivo from health Nu/Nu mice in optical imaging acquisitions and we related it with the optical properties of the diet of the animals. In particular luminescence images of mice feed with normal diet used in animal facilities were acquired using a commercial optical imager. The intensity and the spectral features of the luminescence emission from the animal surface after sunshine exposition and after normal lighting laboratory conditions were measured. The same was done with the pellets of food used to feed the animals. We found a background emission from the entire animal surface and localized light sources in the abdominal/lumbar region. Their intensity can be modulated by the light exposition of the animals before the imaging session and decreases along the time when they are put in darkness. The comparison of the luminescence time decay of animals and pellets suggests that the light sources are related to the persistent luminescence of the molecules contained in the food. So ambient exposure before imaging is important for luminescence imaging in order to keep down the background. The optical properties of food are also important and it necessary to check them before to feed the animals not only in fluorescence imaging but also in luminescence imaging
Plasticity of the rat olfactory bulb during postnatal development: a parametric MRI study.
No full textWe analyzed modifications in transversal relaxation time (T2) and regional cerebral blood volume (rCBV) in two areas of the limbic system,i.e., olfactory bulb (OB) and amygdala (AMY), in pre-puberty and post-puberty female rats. The aim of this work was to extend the knowledgeabout physiological modifications of these MRI parameters at different developmental phases. No significant difference was observed in T2values of the OB between the two groups (pre-puberty: T2 = 86.92 ± 8.57 ms, post-puberty: T2 = 88.11 ± 13.06 ms; mean ± S.D.). On thecontrary T2 values of the AMY were significantly different (P = 0.0001) between the two groups (pre-puberty 76.08 ± 3.2, post-puberty81.77 ± 11.77 ms). rCBV values of OB were significantly different (P = 0.0025) between pre-puberty (0.38 ± 0.12 a.u.) and post-pubertyfemale rats (0.15±0.09 a.u.). A significant decrease in rCBV (P = 5.1×10−13) between pre-puberty and post-puberty females (pre-puberty:0.36 ± 0.12, post-puberty: 0.07 ± 0.05 a.u.) was also observed in the AMY. These findings suggest that in the limbic system, microvascularplasticity parallels neuronal maturation and indicate the importance of an appropriate baseline study in experiments dealing with the limbicsystem performed at different time-points.© 2004 Elsevier Ireland Ltd. All rights reserved
In Vitro and Ex Vivo Models to Study Molecular Trafficking Across the Human Intestinal Barrier
Full text linkThe intestine is a complex organ whose main functions are food digestion and nutrient absorption. It is therefore of great interest for pharmaceutical research as a preferred route for drug delivery. In vitro intestinal models are valuable tools for the preclinical evaluation of absorption, distribution, metabolism, and excretion of new therapeutic formulations; consequently, several attempts have been made to recreate the human intestine barrier in vitro. The models so far set up were aimed at mimicking specific intestinal features related to the molecules or processes under investigation. Artificial membranes are suitable to study passive absorption; systems based on 2D/3D cell cultures reproduce the transcellular pathway; organs-on-a-chip mimic the in vivo cellular and mechanical complexity, allowing the identification of the multiple factors involved in molecular interactions with the intestinal barrier; and intestine explants replicate in full the native organ under controlled conditions, thus providing the most comprehensive in vitro model. All these models have advantages and disadvantages but all have given important contribution to advance the knowledge on the interaction of drugs, toxins, and xenobiotic with the intestinal barrier
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