Self-assembled Angelica sinensis polysaccharide nanoparticles with an instinctive liver-targeting ability as a drug carrier for acute alcoholic liver damage protection.

The present work aimed to study the feasibility of Angelica sinensis polysaccharide (ASP) as an instinctive liver-targeting drug delivery carrier with applications in acute alcoholic liver damage (ALD). Amphipathic cholesteryl hemisuccinate-ASP (ASP-CHEMS) conjugate was synthesized by an esterification reaction and characterized by conventional methods. ASP-CHEMS self-assembled nanoparticles (ACNPs) and Curcumin-loaded ACNPs (Cur/ACNPs) were fabricated with a roughly spherical shape, and their sizes were ranged from 200 to 260 nm in aqueous solution. Compared with free Cur, Cur/ACNPs displayed enhanced solubility, good photostability, and a sustained release of Cur over 72 h. In the in vivo cellular uptake behavior study and in vivo bioimaging experiments, the ACNPs showed excellent liver-targeting capability because of the specific recognition by the asialoglycoprotein receptor (ASGPR) overexpressed on the hepatocyte membrane. The tissue distribution of Cur/ACNPs in mice further demonstrated that ACNPs could distinctly enhance the distribution of Cur into the liver. Furthermore, Cur/ACNPs protected the liver from acute ALD by attenuating oxidative stress and were superior to the protective effects of free Cur and the Cur-loaded CHEMS modified-dextran derivative. According to the results, ACNPs may serve as a promising liver-targeting drug delivery carrier for liver disease prevention.

Gene Silencing Activity and Hepatic Accumulation of Antisense Oligonucleotides Bearing Cholesterol-Conjugated Thiono Triester at the Gap Region.

Cholesterol (Chol) conjugation to the 5' or 3' end of antisense oligonucleotide (ASO) enables delivery to the liver, and Chol conjugation at the gap region can also be expected to improve delivery to the liver. In this study, we synthesized ASOs bearing the Chol-conjugated thiono triester and evaluated their activity and hepatic accumulation. We found that Chol conjugations at the gap region improved in vitro activity and hepatic accumulation when compared to unconjugated ASOs. However, Chol conjugation with phosphorothioate linkage did not improve in vivo activity in the liver, suggesting the importance of cleaving the phosphodiester between ASO and Chol. These results offer useful information for tuning the oligonucleotide structure to improve pharmaceutical properties and designing ASOs for multiple ligand conjugations and combinations with end modification.

Self-assemblies of 5'-cholesteryl-ethyl-phosphoryl zidovudine.

Anti-HIV prodrugs are recently focused on due to their ability of self-assembly, macrophage targeting, and enhanced antiviral effects. Here, an amphiphilic prodrug of zidovudine, an anti-HIV nucleoside analogue, 5'-cholesteryl-ethyl-phosphoryl zidovudine (CEPZ) was synthesized. CEPZ showed some unique physicochemical properties. The solubility of CEPZ in the noncompetitive solvents chloroform and tetrahydrofuran (THF) was very high based on the hydrogen bonds between zidovudine groups, though CEPZ was sparing soluble in alcohols and almost insoluble in water. The typical amphiphilic property of CEPZ was demonstrated according to the Langmuir monolayers at the air/water interface. The LogP of CEPZ was high to 13.78, indicating the high hydrophobicity of amphiphilic CEPZ similar to phospholipids. Homogenous and stable self-assemblies were formed with the mean size of 128.7nm and the zeta potential of -35.4mV after injecting the CEPZ-in-THF solution into water. Hydrophobic interaction between the cholesteryl moieties of CEPZ could drive molecular self-assembly and lead to the formation of spherical vesicles. CEPZ self-assemblies showed strong stability even under high temperature and gravity probably due to the high surface charge. CEPZ was very slowly degraded in neutral solutions (e.g., pH 7.4), but fast in acid solutions (e.g., pH 5.0) and some tissue homogenates. CEPZ was quickly eliminated from the circulation and distributed into the mononuclear phagocyte system (MPS) including the liver, spleen and lung after bolus intravenous administration of CEPZ self-assemblies to mice. The MPS targeting effect of CEPZ self-assemblies makes them become a promising self-assembled drug delivery system to eradicate the HIV hidden in the macrophages.

Improved In Vitro Antileukemic Activity of All-Trans Retinoic Acid Loaded in Cholesteryl Butyrate Solid Lipid Nanoparticles.

All-trans retinoic acid, a hydrophobic drug, has become one of the most successful examples of differentiation agents used for treatment of acute promyelocytic leukemia. On the other hand, histone deacetylase inhibitors, such as cholesteryl butyrate, present differentiating activity and.can potentiate action of drugs such as all-trans retinoic acid. Solid lipid nanoparticles represent a promising alternative for administration of hydrophobic drugs such as ATRA. This study aimed to develop, characterize, and evaluate the cytotoxicity of all-trans retinoic acid-loaded solid lipid nanoparticles for leukemia treatment. The influence of in situ formation of an ion pairing between all-trans retinoic acid and lipophilic amines on the characteristics of the particles (size, zeta potential, encapsulation efficiency) was evaluated. Cholesteryl butyrate, a butyric acid donor, was used as a component of the lipid matrix. In vitro activity on cell viability and distribution of cell cycle phases were evaluated for HL-60, Jurkat, and THP-1 cell lines. The encapsulation efficiency of all-trans retinoic acid in cholesteryl butyrate-solid lipid nanoparticles was significantly increased by the presence of the amine. Inhibition of cell viability by all-trans retinoic acid-loaded solid lipid nanoparticles was more pronounced than the free drug. Analysis of the distribution of cell cycle phases also showed increased activity for all-trans retinoic acid-loaded cholesteryl butyrate-solid lipid nanoparticles, with a clear increase in subdiploid DNA content. The ion pair formation in SLN containing cholesteryl butyrate can be explored as a simple and inexpensive strategy to improve the efficacy and bioavail-ability of ATRA in the treatment of the cancer and metabolic diseases in which this retinoid plays an important role.

Nanovesicles of nitrendipine with lipid complex for transdermal delivery: pharmacokinetic and pharmacodynamic studies.

CONTEXT: Vesicular transdermal delivery can enhance the bioavailability of a drug especially affected by first-pass metabolism, e.g. nitrendipine. However effective transdermal delivery employs permeation enhancer, e.g oleic acid (OA) with ceramide 2, stearic acid, behenic acid, and cholesteryl sulfate lipid complex. OBJECTIVE: This study investigated the preparation, characterization of physicochemical properties, ex vivo permeation using human skin, pharmacokinetic parameters and antihypertensive potential in rats, of nitrendipine-loaded nanovesicles of ceramide 2, stearic acid, behenic acid and cholesteryl sulfate containing oleic acid gel (NOVG). MATERIALS AND METHODS: The nanovesicles were made using film hydration method and characterized for physicochemical properties, ex vivo permeation using human skin, pharmacokinetic parameters and antihypertensive potential. RESULTS: Nitrendipine-loaded nanovesicles of ceramide-2 containing oleic acid (NOV-5) have shown fluxes in the range of 4.88-24.72 µg/cm(2)/h nitrendipine oral suspension (NOS) at equal dose. NOVG-5 has shown almost 33% reduction in blood pressure in the first hour and a further decrease of 25% in the second hour to restore the normal pressure. DISCUSSION: The permeation increases with increase in OA content. OA gets integrated in vesicle wall and enhances its permeability, whereas ceramide content makes sure that skin does not become damaged even after permeation. CONCLUSION: NOVG-5 has shown the most favorable physicochemical properties and good permeation through skin providing good management of hypertension during crucial initial hours.

PET imaging of liposomes labeled with an [¹8F]-fluorocholesteryl ether probe prepared by automated radiosynthesis.

A novel [¹8F]-labeled cholesteryl ether lipid probe was prepared by synthesis of the corresponding mesylate, which was [¹8F]-fluorinated by a [¹8F]KF, Kryptofix-222, K2CO3 procedure. Fluorination was done for 10 minutes at 165°C and took place with conversion between 3 and 17%, depending on conditions. Radiolabelling of the probe and subsequent in situ purification on SEP-Paks were done on a custom-built, fully automatic synthesis robot. Long-circulating liposomes were prepared by hydration (magnetic stirring) of a lipid film containing the radiolabeled probe, followed by fully automated extrusion through 100-nm filters. The [¹8F]-labeled liposomes were injected into nude, tumor-bearing mice, and positron emission tomography (PET) scans were performed several times over 8 hours to investigate the in vivo biodistribution. Clear tumor accumulation, as well as hepatic and splenic uptake, was observed, corresponding to expected liposomal pharmacokinetics. The tumor accumulation 8 hours postinjection accounted for 2.25 ± 0.23 (mean ± standard error of the mean) percent of injected dose per gram (%ID/g), and the tumor-to-muscle ratio reached 2.20 ± 0.24 after 8 hours, which is satisfactorily high for visualization of pathological lesions. Moreover, the blood concentration was still at a high level (13.9 ± 1.5 %ID/g) at the end of the 8-hour time frame. The present work demonstrates the methodology for automated preparation of radiolabeled liposomes, and shows that [¹8F]-labeled liposomes could be suitable as a methodology for visualization of tumors and obtaining short-term pharmacokinetics in vivo.

Cholesterol metabolite, 5-cholesten-3ß-25-diol-3-sulfate, promotes hepatic proliferation in mice.

UNLABELLED: Oxysterols are well known as physiological ligands of liver X receptors (LXRs). Oxysterols, 25-hydroxycholesterol (25HC) and 27-hydroxycholesterol as endogenous ligands of LXRs, suppress cell proliferation via LXRs signaling pathway. Recent reports have shown that sulfated oxysterol, 5-cholesten-3ß-25-diol-3-sulfate (25HC3S) as LXRs antagonist, plays an opposite direction to oxysterols in lipid biosynthesis. The present report was to explore the effect and mechanism of 25HC3S on hepatic proliferation in vivo. Following administration, 25HC3S had a 48 h half life in the circulation and widely distributed in mouse tissues. Profiler™ PCR array and RTqPCR analysis showed that either exogenous or endogenous 25HC3S generated by overexpression of oxysterol sulfotransferase (SULT2B1b) plus administration of 25HC significantly up-regulated the proliferation gene expression of Wt1, Pcna, cMyc, cyclin A, FoxM1b, and CDC25b in a dose-dependent manner in liver while substantially down-regulating the expression of cell cycle arrest gene Chek2 and apoptotic gene Apaf1. Either exogenous or endogenous administration of 25HC3S significantly induced hepatic DNA replication as measured by immunostaining of the PCNA labeling index and was associated with reduction in expression of LXR response genes, such as ABCA1 and SREBP-1c. Synthetic LXR agonist T0901317 effectively blocked 25HC3S-induced hepatic proliferation. CONCLUSIONS: 25HC3S may be a potent regulator of hepatocyte proliferation and oxysterol sulfation may represent a novel regulatory pathway in liver proliferation via inactivating LXR signaling.

The removal from plasma of chylomicrons and remnants is reduced in heterozygous familial hypercholesterolemia subjects with identified LDL receptor mutations: study with artificial emulsions.

Chylomicron remnants bind to both their specific receptors (LRP) and to the LDL receptor (LDLR) in the liver. There is controversy whether disturbances of chylomicron metabolism occur in subjects with familial hypercholesterolemia (FH). The aim of this study was to evaluate whether there are defects on the removal from plasma of chylomicrons and their remnants in heterozygous FH patients with determined LDLR mutations. We studied 20 heterozygous FH patients (43.2±12 years old, 60% males) and 50 normolipidemic subjects matched for age and gender. FH subjects were not in use of LDL-lowering drugs for at least 6 weeks. The removal from plasma of chylomicrons and their remnants was measured by isotopic decay after venous injection of a chylomicron-like emulsion radiolabeled with (14)C-cholesteryl ester ((14)C-CE) and (3)H-triolein ((3)H-TO). These track respectively removal from plasma of chylomicrons and remnants and lipolysis. There was a significant reduction in the fractional catabolic rates (FCR in h(-1)) of (14)C-CE in FH in comparison with normolipidemics: 0.048 (1.46.10(-7); 0.57) vs. 0.71(0.049; 1.62), [median (25th-75th percentile)], p=0.003. No differences were found in FCR of (3)H-TO between FH and controls, respectively 1.62 (1.02; 2.331) and 1.914 (1.34; 2.878), p=0.405. In conclusion heterozygous FH subjects had a significant decrease on the removal from plasma of chylomicrons and their remnants compared with normolipidemics.

Resistance training changes LDL metabolism in normolipidemic subjects: a study with a nanoemulsion mimetic of LDL.

OBJECTIVE: To evaluate the effects of resistance training (RT) on the metabolism of an LDL-like nanoemulsion and on lipid transfer to HDL, an important step of HDL metabolism. METHODS: LDL-like nanoemulsion plasma kinetics was studied in 15 healthy men under regular RT for 1-4 years (age = 25 ± 5 years, VO(2)peak = 50 ± 6 mL/kg/min) and in 15 healthy sedentary men (28 ± 7 years, VO(2)peak = 35 ± 9 mL/kg/min). LDL-like nanoemulsion labeled with (14)C-cholesteryl-ester and (3)H-free-cholesterol was injected intravenously, plasma samples were collected over 24-h to determine decay curves and fractional clearance rates (FCR). Lipid transfer to HDL was determined in vitro by incubating of plasma samples with nanoemulsions (lipid donors) labeled with radioactive free-cholesterol, cholesteryl-ester, triacylglycerols and phospholipids. HDL size, paraoxonase-1 activity and oxidized LDL levels were also determined. RESULTS: The two groups showed similar LDL and HDL-cholesterol and triacylglycerols, but oxidized LDL was lower in RT (30 ± 9 vs. 61 ± 19 U/L, p = 0.0005). In RT, the nanoemulsion (14)C-cholesteryl-ester was removed twice as fast than in sedentary individuals (FCR: 0.068 ± 0.023 vs. 0.037 ± 0.028, p = 0.002), as well as (3)H-free-cholesterol (0.041 ± 0.025 vs. 0.022 ± 0.023, p = 0.04). While both nanoemulsion labels were removed at the same rate in sedentary individuals, RT (3)H-free-cholesterol was removed slower than (14)C-cholesteryl-ester (p = 0.005). HDL size, paraoxonase 1 and the transfer rates to HDL of the four lipids were the same in both groups. CONCLUSIONS: RT accelerated the clearance of LDL-like nanoemulsion, which probably accounts for the oxidized LDL levels reduction in RT. RT also changed the balance of free and esterified cholesterol FCR's. However, RT had no effect on HDL metabolism related parameters.

Exercise training accelerates the removal from plasma of LDL-like nanoemulsion in moderately hypercholesterolemic subjects.

OBJECTIVE: Exercise training improves plasma lipid profile and diminishes risk of coronary heart disease. Previously, we showed that training increases LDL plasma clearance, as tested by an artificial LDL-like nanoemulsion method, presumably by increasing LDL receptor activity. In this study, we investigated whether training could also improve LDL clearance in hypercholesterolemic subjects (HCh) that are exposed to increased risk of cardiovascular events. METHODS: Twenty sedentary HCh and 20 normolipidemic (NL) sedentary volunteers were divided into four groups: 12 HCh submitted to 4-month training program, 8 HCh with no exercise program, 12 NL submitted to 4-month training and 8 NL with no exercise program. An LDL-like nanoemulsion labeled with (14)C-cholesteryl ester was injected intravenously into all subjects and plasma samples were collected during 24 h after injection to determine the fractional clearance rate (FCR, in h(-1)) by compartmental analysis. The study was performed on the first and on the last day of the 4-month study period. RESULTS: In both, trained HCh and NL groups, training increased nanoemulsion FCR by 36% (0.0443+/-0.0126; 0.0602+/-0.0187, p=0.0187 and 0.0503+/-0.0203; 0.0686+/-0.0216, p=0.0827, respectively). After training, LDL cholesterol diminished in both HCh and NL groups. In HCh, but not in NL group, LDL susceptibility to oxidation decreased, but oxidized LDL was unchanged. In both non-trained groups FCR was the same for the last and the 4-month previous evaluation. CONCLUSION: In HCh, exercise training increased the removal of LDL as tested by the nanoemulsion, and this probably accounted for decreased LDL cholesterol and diminished LDL susceptibility to oxidation.

Size-selective uptake of colloidal low density lipoprotein aggregates by cultured white blood cells.

This paper illustrates how principles of colloid science are useful in studying atherosclerosis. Accumulation of foam cells in the arterial intima is a key step in atherogenesis. The extent of foam cell formation is enhanced by low density lipoprotein (LDL) aggregates, and we have previously shown that the size of sphingomyelinase (Smase)-hydrolysis-induced aggregates depends directly on the concentration of ceramide generated in the LDL phospholipid monolayer, mediated by the hydrophobic effect. Here, we focus on the effect of LDL aggregate particle sizes on their subsequent uptake by macrophages. Our data show the first direct measurement of uptake as a function of aggregate size and the first direct comparison of uptake after Smase-catalyzed and vortex-mixing-mediated aggregation. Vortex-mixed aggregates with radii 20-77 nm showed maximal uptake approximately 118 microg sterol/mg protein at a 53 nm intermediate size, consistent with a mathematical model describing competition between aggregate surface area and volume. Smase-treated aggregates with radii 25-211 nm also showed maximal uptake at an intermediate size, approximately 58 microg sterol/mg protein for 132 nm particles, and fit a modified model that incorporated ceramide concentration expressed as aggregate size. This study shows that particle size is significant and composition may also be a factor in LDL uptake.

[Lipid transfer to HDl in women with type 1 diabetes]. / Transferência de lípides para a lipoproteína de alta densidade (HDl) em mulheres com diabetes melito tipo 1.

INTRODUCTION: People with type 1 diabetes mellitus (T1DM) have an increased risk of cardiovascular disease and may still have a normal lipid profile. In order to clarify whether normal HDL cholesterol levels may conceal defects in HDL function, we have studied the transfer of lipids to HDL in T1DM. METHODS: Twenty-one young women with T1DM were compared with 21 non-diabetic women. Nanoemulsion preparations were used as lipid donor to HDL: one labeled with (3)H-triglycerides and 14C-free cholesterol and the other with (3)H-cholesteryl esters and 14C-phospholipids. These preparations were incubated with plasma samples for 1h. After chemical precipitation, the supernatant containing HDL was counted for radioactivity. RESULTS: No difference in transfer was observed to nanoemulsion HDL from cholesteryl esters, triglycerides, free cholesterol and phospholipids. CONCLUSION: Simultaneous lipid transfer to HDL was not affected in T1DM patients. This suggests that the disease does not alter lipoprotein composition and transfer protein action in such way as to disturb HDL metabolism.

Effect of a cholesterol-rich diet on the metabolism of the free and esterified cholesterol components of a nanoemulsion that resembles LDL in rabbits.

We have shown that the free cholesterol (FC) and the cholesteryl ester (CE) moieties of a nanoemulsion with lipidic structure resembling low-density lipoproteins show distinct metabolic fate in subjects and that this may be related to the presence of dyslipidemia and atherosclerosis. The question was raised whether induction of hyperlipidemia and atherosclerosis in rabbits would affect the metabolic behavior of the two cholesterol forms. Male New Zealand rabbits aged 4-5 months were allocated to a control group (N = 17) fed regular chow and to a 1% cholesterol-fed group (N = 13) during a 2-month period. Subsequently, the nanoemulsion labeled with 3H-FC and 14C-CE was injected intravenously for the determination of plasma kinetics and tissue uptake of the radioactive labels. In controls, FC and CE had similar plasma kinetics (fractional clearance rate, FCR = 0.234 +/- 0.056 and 0.170 +/- 0.038 h-1, respectively; P = 0.065). In cholesterol-fed rabbits, the clearance of both labels was delayed and, as a remarkable feature, FC-FCR (0.089 +/- 0.033 h-1) was considerably greater than CE-FCR (0.046 +/- 0.010 h-1; P = 0.026). In the liver, the major nanoemulsion uptake site, uptake of the labels was similar in control animals (FC = 0.2256 +/- 0.1475 and CE = 0.2135 +/- 0.1580%/g) but in cholesterol-fed animals FC uptake (0.0890 +/- 0.0319%/g) was greater than CE uptake (0.0595 +/- 0.0207%/g; P < 0.05). Therefore, whereas in controls, FC and CE have similar metabolism, the induction of dyslipidemia and atherosclerosis resulted in dissociation of the two forms of cholesterol.

Transferência de lípides para a lipoproteína de alta densidade (HDl) em mulheres com diabetes melito tipo 1 / Lipid transfer to HDl in women with type 1 diabetes

INTRODUÇÃO: Os portadores de diabetes melito tipo 1 (DM1) possuem aumentado risco de doença cardiovascular e, ainda assim, podem apresentar perfil lipídico normal. Para esclarecer se os níveis normais de HDL podem ocultar defeitos na função, foram estudados a transferência de lípides para a HDL em DM1. MÉTODOS: Vinte e uma mulheres jovens portadoras de DM1 foram comparadas com 21 mulheres não-diabéticas. Nanoemulsões foram usadas como doadoras de lípides para HDL: uma marcada com ³H-triglicérides e 14C-colesterol livre e outra com ³H-éster de colesterol e 14C-fosfolípides. Após 1 hora de incubação com amostras de plasma, seguida por precipitação química, o sobrenadante, contendo HDL, teve a radioatividade contada. RESULTADOS: Nenhuma diferença foi encontrada nas transferências dos ésteres de colesterol, triglicérides, colesterol livre e fosfolípides para as HDL. CONCLUSÃO: A transferência de lípides para a HDL não está afetada em portadoras de DM1. Isso sugere que a doença não altera a composição de lipoproteínas e a ação de proteínas de transferência.

INTRODUCTION: People with type 1 diabetes mellitus (T1DM) have an increased risk of cardiovascular disease and may still have a normal lipid profile. In order to clarify whether normal HDL cholesterol levels may conceal defects in HDL function, we have studied the transfer of lipids to HDL in T1DM. METHODS: Twenty-one young women with T1DM were compared with 21 non-diabetic women. Nanoemulsion preparations were used as lipid donor to HDL: one labeled with ³H-triglycerides and 14C-free cholesterol and the other with ³H-cholesteryl esters and 14C-phospholipids. These preparations were incubated with plasma samples for 1h. After chemical precipitation, the supernatant containing HDL was counted for radioactivity. RESULTS: No difference in transfer was observed to nanoemulsion HDL from cholesteryl esters, triglycerides, free cholesterol and phospholipids. CONCLUSION: Simultaneous lipid transfer to HDL was not affected in T1DM patients. This suggests that the disease does not alter lipoprotein composition and transfer protein action in such way as to disturb HDL metabolism.

Effect of a cholesterol-rich diet on the metabolism of the free and esterified cholesterol components of a nanoemulsion that resembles LDL in rabbits

We have shown that the free cholesterol (FC) and the cholesteryl ester (CE) moieties of a nanoemulsion with lipidic structure resembling low-density lipoproteins show distinct metabolic fate in subjects and that this may be related to the presence of dyslipidemia and atherosclerosis. The question was raised whether induction of hyperlipidemia and atherosclerosis in rabbits would affect the metabolic behavior of the two cholesterol forms. Male New Zealand rabbits aged 4-5 months were allocated to a control group (N = 17) fed regular chow and to a 1 percent cholesterol-fed group (N = 13) during a 2-month period. Subsequently, the nanoemulsion labeled with ³H-FC and 14C-CE was injected intravenously for the determination of plasma kinetics and tissue uptake of the radioactive labels. In controls, FC and CE had similar plasma kinetics (fractional clearance rate, FCR = 0.234 ± 0.056 and 0.170 ± 0.038 h-1, respectively; P = 0.065). In cholesterol-fed rabbits, the clearance of both labels was delayed and, as a remarkable feature, FC-FCR (0.089 ± 0.033 h-1) was considerably greater than CE-FCR (0.046 ± 0.010 h-1; P = 0.026). In the liver, the major nanoemulsion uptake site, uptake of the labels was similar in control animals (FC = 0.2256 ± 0.1475 and CE = 0.2135 ± 0.1580 percent/g) but in cholesterol-fed animals FC uptake (0.0890 ± 0.0319 percent/g) was greater than CE uptake (0.0595 ± 0.0207 percent/g; P < 0.05). Therefore, whereas in controls, FC and CE have similar metabolism, the induction of dyslipidemia and atherosclerosis resulted in dissociation of the two forms of cholesterol.

Uptake by breast carcinoma of a lipidic nanoemulsion after intralesional injection into the patients: a new strategy for neoadjuvant chemotherapy.

OBJECTIVE: Previously we showed that after intravenous injection a lipidic nanoemulsion concentrates in breast carcinoma tissue and other solid tumors and may carry drugs directed against neoplastic tissues. Use of the nanoemulsion decreases toxicity of the chemotherapeutic agents without decreasing the anticancer action. Currently, the hypothesis was tested whether the nanoemulsion concentrates in breast carcinoma tissue after locoregional injection. METHODS: Three different techniques of injection of the nanoemulsion were tested in patients scheduled for surgical treatment: G1 (n=4) into the mammary tissue 5 cm away from the tumor; G2 (n=4) into the peritumoral mammary tissue; G3 (n=6) into the tumoral tissue. The nanoemulsion labeled with radioactive cholesteryl oleate was injected 12 h before surgery; plasma decay of the label was determined from blood samples collected over 24 h and the tissue fragments excised during the surgery were analyzed for radioactivity uptake. RESULTS: Among the three nanoemulsion injection techniques, G3 showed the greatest uptake (data expressed in c.p.m/g of tissue) by the tumor (44,769+/-54,749) and by the lymph node (2356+/-2966), as well as the greatest concentration in tumor compared to normal tissue (844+/-1673). In G1 and G2, uptakes were, respectively, tumor: 60+/-71 and 843+/-1526; lymph node: 263+/-375 and 102+/-74; normal tissue: 139+/-102 and 217+/-413. CONCLUSIONS: Therefore, with intralesional injection of the nanoemulsion, a great concentration effect can be achieved. This injection technique may be thus a promising approach for drug-targeting in neoadjuvant chemotherapy in breast cancer treatment.

Long-circulating, pH-sensitive liposomes sterically stabilized by copolymers bearing short blocks of lipid-mimetic units.

A major hurdle towards in vivo utilization of pH-sensitive liposomes is their prompt sequestration by reticuloendothelial system and hence short circulation time. Prolonged circulation of liposomes is usually achieved by incorporation of pegylated lipids, which have been frequently reported to deteriorate the acid-triggered release. In this study we evaluate the ability of four novel nonionic copolymers, bearing short blocks of lipid-mimetic units to provide steric stabilization of DOPE:CHEMs liposomes. The vesicles were prepared using the lipid film hydration method and extrusion, yielding liposomes of 120-160 nm in size. Their pH-sensitivity was monitored via the release of encapsulated calcein. The incorporation of the block copolymers at concentration up to 10 mol% did not deteriorate the pH-sensitivity of the liposomes. A selected formulation was tested for stability in presence of 25% human plasma and proved to significantly outclass the plain DOPE:CHEMs liposomes. The ability of calcein-loaded liposomes to deliver their cargo inside EJ cells was investigated using fluorescent microscopy and the results show that the surface-modified vesicles are as effective to ensure intracellular delivery as plain liposomes. The pharmacokinetics and organ distribution of a selected formulation, containing a copolymer bearing four lipid anchors was investigated in comparison to plain liposomes and PEG (2000)-DSPE stabilized liposomes. The juxtaposition of the blood clearance curves and the calculated pharmacokinetic parameters show that the block copolymer confers superior longevity in vivo. The block copolymers utilized in this study can be consider as promising sterically stabilizing agents for pH-sensitive liposomes.

Lipolysis of emulsion models of triglyceride-rich lipoproteins is altered in male patients with abdominal aorta aneurysm.

Disorders of the lipid metabolism may play a role in the genesis of abdominal aorta aneurysm. The present study examined the intravascular catabolism of chylomicrons, the lipoproteins that carry the dietary lipids absorbed by the intestine in the circulation in patients with abdominal aorta aneurysm. Thirteen male patients (72 +/- 5 years) with abdominal aorta aneurysm with normal plasma lipid profile and 13 healthy male control subjects (73 +/- 5 years) participated in the study. The method of chylomicron-like emulsions was used to evaluate this metabolism. The emulsion labeled with 14C-cholesteryl oleate and (3)H-triolein was injected intravenously in both groups. Blood samples were taken at regular intervals over 60 min to determine the decay curves. The fractional clearance rate (FCR) of the radioactive labels was calculated by compartmental analysis. The FCR of the emulsion with (3)H-triolein was smaller in the aortic aneurysm patients than in controls (0.025 +/- 0.017 vs 0.039 +/- 0.019 min-1; P < 0.05), but the FCR of 14C-cholesteryl oleate of both groups did not differ. In conclusion, as indicated by the triglyceride FCR, chylomicron lipolysis is diminished in male patients with aortic aneurysm, whereas the remnant removal which is traced by the cholesteryl oleate FCR is not altered. The results suggest that defects in the chylomicron metabolism may represent a risk factor for development of abdominal aortic aneurysm.

Effects of amino acid substitutions at glycine 420 on SR-BI cholesterol transport function.

Scavenger receptor class B type I (SR-BI) facilitates the uptake of HDL cholesteryl esters (CEs) in a two-step process involving binding of HDL to its extracellular domain and transfer of HDL core CEs to a metabolically active membrane pool, where they are subsequently hydrolyzed by a neutral CE hydrolase. Recently, we characterized a mutant, G420H, which replaced glycine 420 in the extracellular domain of SR-BI with a histidine residue and had a profound effect on SR-BI function. The G420H mutant receptor exhibited a reduced ability to mediate selective HDL CE uptake and was unable to deliver HDL CE for hydrolysis, despite the fact that it retained the ability to bind HDL. This did not hold true if glycine 420 was replaced with an alanine residue; G420A maintained wild-type HDL binding and cholesterol transport activity. To further understand the role that glycine 420 plays in SR-BI function and why there was a disparity between replacing glycine 420 with a histidine versus an alanine, we generated a battery of point mutants by substituting glycine 420 with amino acids possessing side chains that were charged, hydrophobic, polar, or bulky and tested the resulting mutants for their ability to support HDL binding, HDL cholesterol transport, and delivery for hydrolysis. The results indicated that substitution with a negatively charged residue or a proline impaired cell surface expression of SR-BI or its interaction with HDL, respectively. Furthermore, substitution of glycine 420 with a positively charged residue reduced HDL CE uptake as well as its subsequent hydrolysis.

Lipolysis of emulsion models of triglyceride-rich lipoproteins is altered in male patients with abdominal aorta aneurysm

Disorders of the lipid metabolism may play a role in the genesis of abdominal aorta aneurysm. The present study examined the intravascular catabolism of chylomicrons, the lipoproteins that carry the dietary lipids absorbed by the intestine in the circulation in patients with abdominal aorta aneurysm. Thirteen male patients (72 ± 5 years) with abdominal aorta aneurysm with normal plasma lipid profile and 13 healthy male control subjects (73 ± 5 years) participated in the study. The method of chylomicron-like emulsions was used to evaluate this metabolism. The emulsion labeled with 14C-cholesteryl oleate and ³H-triolein was injected intravenously in both groups. Blood samples were taken at regular intervals over 60 min to determine the decay curves. The fractional clearance rate (FCR) of the radioactive labels was calculated by compartmental analysis. The FCR of the emulsion with ³H-triolein was smaller in the aortic aneurysm patients than in controls (0.025 ± 0.017 vs 0.039 ± 0.019 min-1; P < 0.05), but the FCR of14C-cholesteryl oleate of both groups did not differ. In conclusion, as indicated by the triglyceride FCR, chylomicron lipolysis is diminished in male patients with aortic aneurysm, whereas the remnant removal which is traced by the cholesteryl oleate FCR is not altered. The results suggest that defects in the chylomicron metabolism may represent a risk factor for development of abdominal aortic aneurysm.