Fluorescent cell-traceable dexamethasone-loaded liposomes for the treatment of inflammatory liver diseases (original) (raw)
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Nanomedicine: Nanotechnology, Biology and Medicine, 2014
The encapsulation of drugs into liposomes aims to enhance their efficacy and reduce their toxicity. Corticosteroid-loaded liposomes are currently being evaluated in patients suffering from rheumatoid arthritis, atherosclerosis, colitis, and cancer. Here, using several different fluorophore-labeled formulations, we comprehensively studied the impact of liposome encapsulation of the prototypic corticosteroid dexamethasone on various primary human cells in vitro. Liposomal dexamethasone targeted several primary cell types in a dose and time-dependent manner, but specifically reduced cytotoxicity against human fibroblasts and macrophages in comparison to the solute drug. Furthermore, macrophage maturation and polarization markers were altered. Interestingly, liposomal dexamethasone induced proinflammatory cytokine secretion (specifically TNF, IL1β, IL6) in unstimulated cells, but reduced this response under inflammatory conditions. Monocyte and macrophage migration was significantly inhibited by dexamethasone-loaded liposomes. The findings indicate that the encapsulation of dexamethasone into liposomes modulates their cellular mechanism of action, and provides important indications for follow-up in vivo investigations.
Pharmaceutics
Liver inflammation represents a major clinical problem in a wide range of pathologies. Among the strategies to prevent liver failure, dexamethasone (DXM) has been widely used to suppress inflammatory responses. The use of nanocarriers for encapsulation and sustained release of glucocorticoids to liver cells could provide a solution to prevent severe side effects associated with systemic delivery as the conventional treatment regime. Here we describe a nanostructured lipid carrier developed to efficiently encapsulate and release DXM. This nano-formulation proved to be stable over time, did not interact in vitro with plasma opsonins, and was well tolerated by primary non-parenchymal liver cells (NPCs). Released DXM preserved its pharmacological activity, as evidenced by inducing robust anti-inflammatory responses in NPCs. Taken together, nanostructured lipid carriers may constitute a reliable platform for the delivery of DXM to treat pathologies associated with chronic liver inflammat...
Transient effects of empty liposomes on hepatic macrophage populations in rats
Journal of Toxicologic Pathology, 2016
Liposomes have been used as a vehicle for encapsulating chemicals or toxins in toxicological studies. We investigated the transient effects of empty liposomes on hepatic macrophages by applying a single intravenous injection at a dose of 10 ml/kg body weight in 6-week-old male F344 rats. One day after injection, the numbers of hepatic macrophages reacting to CD163, CD68, Iba-1, MHC class II, Gal-3 and CD204 were significantly increased in liposome-treated rats. CD163 + Kupffer cells and CD68 + macrophages with increased phagocytic activity in hepatic lobules were most sensitive. The histological architecture of the liver was not changed following liposome injection; however, hepatocytes showed increased proliferating activity, demonstrable with proliferation marker immunostaining and by an increase in gene profiles related to the cell cycle. In the liposome-treated rats, interestingly, AST and ALT values were significantly decreased, and MCP-1, IL-1β and TGF-β1 mRNAs were significantly increased. Collectively, the present study found that hepatic macrophages activated by liposomes can influence liver homeostasis. This information would be useful for background studies on liposomes.
Addressing Liver Fibrosis with Liposomes Targeted to Hepatic Stellate Cells
Journal of Liposome Research, 2007
Liver fibrosis is a chronic disease that results from hepatitis B and C infections, alcohol abuse or metabolic and genetic disorders. Ultimately, progression of fibrosis leads to cirrhosis, a stage of the disease characterized by failure of the normal liver functions. Currently, the treatment of liver fibrosis is mainly based on the removal of the underlying cause of the disease and liver transplantation, which is the only treatment for patients with advanced fibrosis. Hepatic stellate cells (HSC) are considered to be key players in the development of liver fibrosis. Chronically activated HSC produces large amounts of extracellular matrix and enhance fibrosis by secreting a broad spectrum of cytokines that exert pro-fibrotic actions in other cells, and in an autocrine manner perpetuate their own activation. Therefore, therapeutic interventions that inhibit activation of HSC and its pro-fibrotic activities are currently under investigation worldwide. In the present study we applied targeted liposomes as drug carriers to HSC in the fibrotic liver and explored the potential of these liposomes in antifibrotic therapies. Moreover, we investigated effects of bioactive compounds delivered by these liposomes on the progression of liver fibrosis. To our knowledge, this is the first study demonstrating that lipid-based drug carriers can be selectively delivered to HSC in the fibrotic liver. By incorporating the bioactive lipid DLPC, these liposomes can modulate different processes such as inflammation and fibrogenesis in the fibrotic liver. This dual functionality of liposomes as a drug carrier system with intrinsic biological effects may be exploited in new approaches to treat liver fibrosis.
Uptake and processing of immunoglobulin-coated liposomes by subpopulations of rat liver macrophages
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1988
In rive uptake an0 processing by liver macruphages (Kupffer cells) of liposome~, covalently coated with rabbit immuno~obulln (|g ilposomes) was studied following intrave~us injection in rats. Rabbit Ig iiposomas were labeled with trace ~uneunts of eho|es~ryq UC]oleate and [3Hiehelesteryl hex~ecyl ether. | h after |n|e~ion of the liposomes, the non-perenchymal cells were iso|atod and subjected to cen~fugal elutriafion with stepwise-lncreasing flow rates; thus, five snb-fr~ons of Kupffer edis were obtalned ranging in size from 9 to 14 pm in dhuneter. The cells were assayod for peroxidese ~tivity and protein content° Rabbit |8 |iposomes were taken up preferentially by Kupffer ceils with diameters is~rger than II pin, which constitute less than 2S% of the total Kupffer cell population. The intralysosomal degradation of the ingos~ iiposomas was monitored by measuring the 3H/uC ratio of the cells. Due to the rapid release from the ceils of the [uC~oleate formed from the ¢ho|esteryi[UC]o|eate and the virtual|y complete retention of the non-metabolizab|e [3H]cho|esteryl hexadecyl ether the 3H/UC ratio of the cells incre~es with proceeding hydrelysls of the liposomes. Thus, we were able to show that~ in v|vo, the Kupffer ceDs of the larger s~e classes, are not only mo~e active in liposome u~eke~ but ere also su~tanfially more active in liposome degradation than smaller ceils. The maintenance of the observed heterogeneity of rat Hver Eupffer e,,ll~ with respect to liposome uptake under in vitro culture conditions, was examined. Subfractions were maintained in mono|ayer culture for 2 days and incubated with rabbit |g lipo~me$. Binding and uptake of Hposomes by the cells was monitored by measuring ceil-assucinted radioactivity at 4°C and 37°C, respectively. In contrast to our in vivo rosults, we observed maximal in vitro fiposome binding and uptake in these subfn~cfions containing small cells (10-H pm diameter), while the fractions containing ceils larger than |2/~m, which were more active in vivo, were substantially less active than the smaller ceils. The maximum we observed was even more pronounced when the llposeme concentration was ineroased. We conclude that liver macrephase subfractions that barely participate in liposome uptake from the bloodstream in vivo, possess the potential to develop the capacity in vitro to phagocy|ose rabbit Ig.coated |iposomes to extents equal to or even higher than the cells belonging to those subfractions containing the phagocyticeHy most active cells under in vivo conditions. Abbreviations: Ig, immunogiobulin; Hopes, 4-(2-hydroxyethyl)-l-piperazineethanesulfomc acid; MPB-PE, maleimido-4-(p.phenylbutyryl)phesphatidy!ethanolamine; PBS, phosphatebuffered safine.
Development, Physicochemical and In-Vitro Evaluation of Dexamethasone-Containing Liposomes
The purpose of this research was to develop dexamethasone-containing liposomes (DCL) based on different combination of cholesterol and soy L-lecithin by lipid film hydration method. Although many studies are available on DCL, none of them provides sufficiently convincing technologies for manufacturing DCL with all the standardized process parameters such as amount of drug loading, drug-release, liposome size, etc. Therefore, more research is required in the field. Different process parameters such as drug-excipient interaction (by FTIR study), surface morphology by scanning electron microscope (SEM), particle size analysis and in-vitro drug release study were done. The average particle size of the liposomes was 1 μm. It was found that drug loading of the formulations were between 1.39% w/w and 1.49% w/w. In vitro drug release study shows that between 87% and 96% release of drug obtained from the different experimental liposomes in 500 min. Drug release was found to follow Korsmeyer kinetics.
Interaction of immunoglobulin-coupled liposomes with rat liver macrophages in vitro
Experimental Cell Research, 1987
The interaction between liposomes coated with covalently linked rabbit immunoglobulin (RbIg-liposomes), and rat liver macrophages (Kupffer cells) in monolayer culture was studied biochemically with radioactive tracers andmorphologically by electron microscopy. The attachment of immunoglobulin (Ig) to liposomes caused a five-fold increase in liposome uptake by the Kupffer cells at 37°C in comparison with uncoated liposomes. The uptake was linear with time for at least 4 h and linear with liposome concentration up to a lipid concentration of 0.2 mM. At 4°C uptake, probably representing cell surface-bound liposomes, was reduced to a level of approx. 20 % of the 37°C values. Involvement of the Fc receptor in the uptake process was indicated by the reduction of RbIg-liposome uptake by more than 75% as a result of preincubating the cells with heat-aggregated human or rabbit Ig at concentrations (less than 2 mg/ml) at which bovine serum albumin (BSA) had virtually no effect on uptake. At high concentrations (10-35 mg/ml), however, albumin also reduced liposome uptake significantly (20-30%), which suggests an interaction of the RbIg-liposomes with the Kupffer cells that is partially non-specific. RbIg-liposome uptake was dependent on the amount of RbIg coupled to the liposomes. Maximal uptake values were reached at about 200 ug RbIg/umol liposomal lipid. Electron microscopic observations on cells incubated with horseradish peroxidase-containing RbIg-liposomes demonstrated massive accumulation of peroxidase reaction product in intracellular vacuoles, showing that the uptake observed by label association represents true internalization. 0
Biomaterials, 2019
Myeloid immune cells promote inflammation and fibrosis in chronic liver diseases. Drug delivery systems, such as polymers, liposomes and microbubbles, efficiently target myeloid cells in healthy liver, but their targeting properties in hepatic fibrosis remain elusive. We therefore studied the biodistribution of three intravenously injected carrier material, i.e. 10 nm poly(N-(2-hydroxypropyl)methacrylamide) polymers, 100 nm PEGylated liposomes and 2000 nm poly(butyl cyanoacrylate) microbubbles, in two fibrosis models in immunocompetent mice. While whole-body imaging confirmed preferential hepatic uptake even after induction of liver fibrosis, flow cytometry and immunofluorescence analysis revealed markedly decreased carrier uptake by liver macrophage subsets in fibrosis, particularly for microbubbles and polymers. Importantly, carrier uptake co-localized with immune infiltrates in fibrotic livers, corroborating the intrinsic ability of the carriers to target myeloid cells in areas of inflammation. Of the tested carrier systems liposomes had the highest uptake efficiency among hepatic myeloid cells, but the lowest specificity for cellular subsets. Hepatic fibrosis affected carrier uptake in liver and partially in spleen, but not in other tissues (blood, bone marrow, lung, kidney). In conclusion, while drug carrier systems target distinct myeloid cell populations in diseased and healthy livers, hepatic fibrosis profoundly affects their targeting efficiency, supporting the need to adapt nanomedicine-based approaches in chronic liver disease.