Ultrasmall All-In-One Nanodots Formed via Carbon Dot-Mediated and Albumin-Based Synthesis: Multimodal Imaging-Guided and Mild Laser-Enhanced Cancer Therapy.

Integration of multiple diagnostic/therapeutic modalities into a single system with ultrasmall size, excellent photothermal/photodynamic properties, high cellular uptake efficiency, nuclear delivery capacity, rapid renal clearance, and good biosafety is highly desirable for cancer theranostics, but still remains challenging. Here, a novel type of multifunctional nanodots (denoted as BCCGH) was synthesized by mixing bovine serum albumin, carbon dots, and metal ions (Cu2+ and Gd3+), followed by the conjugation with a photosensitizer (HPPH). The nanodots hold great promise for fluorescence/photoacoustic/magnetic resonance/photothermal imaging-guided synergistic photothermal/photodynamic therapy (PDT) because of their appealing properties such as high photothermal conversion efficiency (68.4%), high longitudinal relaxivity (11.84 mM-1 s-1, 7 T), and superior colloidal stability with negligible Gd3+ release. Benefiting from the massive cellular uptake, endoplasmic reticulum/mitochondrion-targeting ability, and mild near-infrared laser irradiation-promoted nuclear delivery of BCCGH, a high anticancer therapeutic efficiency is achieved in the subsequent in vitro PDT. Besides, as revealed by the in vivo/ex vivo results, the nanodots also exhibit excellent tumor accumulation, efficient renal clearance, complete tumor ablation, and exceptional biosafety. To summarize, this work develops a carbon dot-mediated and albumin-based synthetic approach for constructing ultrasmall and multifunctional nanodots, which may hold great potential for cancer theranostics and beyond.

Fabrication of peptide-linked albumin nanoconstructs for receptor-mediated delivery of asiatic acid to the brain as a preventive measure in cognitive impairment: optimization, in-vitro and in-vivo evaluation.

The aim of the study was to evaluate the neuroprotective activity of glutathione (GU)-conjugated asiatic acid (AA) loaded albumin nanoparticles and establishing the drug targeting efficiency (DTE) of GU as a selective ligand for brain-targeted delivery. Albumin nanoparticles were prepared by desolvation technique and optimized using quality by design (QbD) approach. GU was conjugated with nanoparticles by carbodiimide reaction and characterized by its size and zeta potential using dynamic light scattering phenomenon. Dialysis bag technique was employed for in-vitro release study and in-vivo brain targeting efficiency was evaluated in Sprague-Dawley rats (75 mg/kg, i.p.). Neuroprotective activity was evaluated against scopolamine-induced dementia in rats. Resultant brain bioavailability of nanoparticles with 100.2 nm size and 71.59% entrapment efficiency (EE), was found 7-fold higher than AA dispersion with 293% DTE for the brain. Conjugated nanoparticles showed significantly high percentage correct alternation (p < .05), low escape latency time (p < .01), cholinesterase inhibition (p < .01) and ameliorated GU levels (p < .01) as compared to diseased animals. GU showed potential to enhance the brain delivery of AA with ameliorated neuroprotective activity due to enhanced bioavailability. This concept can serve as a platform technology for similar potential neurotherapeutics, whose clinical efficacy is still challenging owing to poor bioavailability.

Statistical optimization of chitosan nanoparticles as protein vehicles, using response surface methodology.

BACKGROUND: There has been increased attention given to polymeric nanoparticles as protein carriers. In this regard, chitosan/tripolyphosphate (TPP) nanoparticles are considered to be a simple and efficient carrier. However, to have an ideal protein release profile, we need to optimize the properties of the carrier. METHODS: This study examined the influence of 4 critical process parameters on the physicochemical characteristics of final nanoparticles. Chitosan-based nanoparticles were produced by ionic gelation, and then the size, polydispersity and zeta potential of those resulting nanoparticles were evaluated. Subsequently, the encapsulation efficiency of bovine serum albumin as model protein was investigated. RESULTS: The morphologies of nanoparticles were characterized using field emission scanning electron microscopy (FE-SEM). Linear mathematical models were presented for each response through 3 levels using Central Composite Design with the help of design of experiments software, and formulation optimization was performed. CONCLUSIONS: Such research will serve as a basic study in protein loading into TPP cross-linked chitosan nanoparticles.

[A comparison study of pharmacokinetics between bufalin-loaded bovine serum albumin nanoparticles and bufalin in rats].

OBJECTIVE: To determine the bufalin concentration in rats' plasma by establishing a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method, and to evaluate and compare the pharmacokinetic characteristics of bufalin-loaded bovine serum albumin nanoparticles (bufalin-BSA-NP) and bufalin. METHODS: Thirty Wistar rats were randomly divided into six groups with five rats in each group, and administered with a single dose of 0.6, 0.3 and 0.15 mg/kg of bufalin-BSA-NP or bufalin, respectively. After the administration, blood samples were collected from the orbital venous plexus at designed time points (1, 5, 8, 10, 15, 20, 30, 45, 60, 120, 180, 300 and 480 min). The concentration of bufalin in plasma at different sampling time points was determined by HPLC-MS/MS. The pharmacokinetic parameters were calculated and compared. RESULTS: The established HPLC-MS/MS method had high linearity, precision and accuracy. The blood plasma area under curve, the mean retention time and the terminal half life of bufalin-BSA-NP were 1.19 to 1.81, 2.12 to 3.61 and 2.17 to 2.94 times of bufalin, respectively. CONCLUSION: Bufalin-BSA-NP has the function of sustained release thus to prolong the bufalin remaining in blood.

In vitro photodynamic therapy on human U251 glioma cells with a novel photosensitiser ZnPcS4-BSA.

This article reports the phototoxicity effects of a novel photosensitiser ZnPcS4-BSA on human U251 glioma cells in vitro. The cellular uptake of ZnPcS4-BSA by U251 glioma cells was quantified by UV-spectra, and the optimal incubation time was determined. Human U251 glioma cells were incubated in ZnPcS4-BSA of various concentrations, and received laser irradiation of different energy densities. Cell survival rates were measured by CCK-8 assay. Flow cytometer was used to detect apoptosis. Expression of vascular endothelial growth factor (VEGF) gene was detected by real-time PCR in U251 cells after photodynamic therapy (PDT), and ß-actin was used as an internal standard. The normal U251 cells severed as controls. Results indicate that the uptake of ZnPcS4-BSA by U251 glioma cells reaches maximum after incubation for 4 hours. ZnPcS4-BSA with different concentrations without light irradiation has no significant effects on cell survival rates. Without ZnPcS4-BSA incubation, cell survival rate of high-dose group (400 J/cm(2)) is the lowest, whereas no significant difference has been found between any other two groups. At laser irradiation of 150 J/cm(2), inhibition rates of the cells increase with ZnPcS4-BSA concentration, and half-inhibitory concentration (IC50) is 0.16 µmol/L. Apoptosis rate of the cells after PDT is significantly higher than that of the control group (p < 0.01). The VEGF expression in the cells increases 5.616 times after PDT. The novel ZnPcS4-BSA is a good photosensitiser for PDT towards U251 glioma cells. The ZnPcS4-BSA based PDT can induce effective apoptosis.

A protein/antibiotic releasing poly(lactic-co-glycolic acid)/lecithin scaffold for bone repair applications.

Novel poly(lactic-co-glycolic acid) (PLGA)-hybridizing-lecithin scaffolds loaded with drug or protein were prepared with water/oil/water techniques and sintering microspheres technique. In such fabricated composite scaffolds (abbreviated "PLGA/Lec-SMS"), the introduction of lecithin component has been proven capable of largely enhancing Gentamicin (GS) and protein (Bovine Serum Albumin) encapsulation efficiency. The in vitro GS and BSA releasing profiles of PLGA/Lec-SMS system were plotted basing over 60 days' and 18 days' data collection, respectively. It indicates a sustained releasing tendency despite a burst at the very beginning. The antibacterial properties of GS-laden scaffolds were determined in vitro, and the antibacterial activity of scaffolds was enhanced by incorporating lecithin into PLGA bulks. Additionally, mesenchymal stem cells (MSCs) were seeded onto PLGA-SMS and PLGA/Lec-SMS in vitro. The outcome confirmed PLGA/Lec(5%)-SMS functions to improve MSC proliferation and also to enhance general ALP production and calcium secretion which is the vital markers for osteogenesis. In conclusion, this newly designed antibiotic releasing PLGA/Lec-SMS is promising for bone-repairing therapeutics.

Photocrosslinked anhydride systems for long-term protein release.

Injectable delivery systems are attractive as vehicles for localized delivery of therapeutics especially in the context of regenerative medicine. In this study, the potential of photocrosslinked polyanhydride (PA) networks as an encapsulation matrix for long-term delivery of macromolecules was studied. The in vitro release of two model proteins (horseradish peroxidase (HRP) and bovine serum albumin labeled with fluorescein isothiocyanate (FITC-BSA)) was evaluated from crosslinked networks composed of sebacic acid dimethacrylate (MSA), 1,6-bis-carboxyphenoxyhexane dimethacrylate (MCPH), and poly(ethylene glycol) diacrylate (PEGDA), supplemented with calcium carbonate. Prior to incorporation into the networks, proteins were formulated by dilution in a cyclodextrin excipient followed by gelatin-based wet granulation. Protein release was quantified by activity assay (HRP) or fluorescence (FITC-BSA). Each protein was readily released from the networks with a unique release behavior. Most importantly, release of protein with retention of activity was achieved for durations ranging from 1 week to 4 months. The released HRP was additionally visualized using SDS-PAGE. In general, a more hydrophobic network resulted in slower rates of protein release. Incorporation of PEGDA into the matrices was critical for maintenance of integrity during degradation. These results suggest that this system may be useful as an injectable delivery system for long-term delivery of macromolecules.

Study on adsorption mechanism of proteins onto synthetic calcium hydroxyapatites through ionic concentration measurements.

To clarify the adsorption mechanism of proteins onto calcium hydroxyapatite (Hap), the kinetic studies of dissolution and ion-exchange properties of synthetic Hap particles in the absence and presence of proteins were examined at 15 degrees C. In the absence of proteins, Hap particles slightly dissolved to give low amounts of calcium ([Ca(2+)] = 0.09-0.14 micromol m(-2)) and phosphate [PO(4) (3-)] = 0.01-0.08 micromol m(-2)) ions in KCl, CaCl(2), BaCl(2) and AlCl(3) solutions. The [Ca(2+)] increased with increase in the Ca/P ratio of Hap, while the [PO(4) (3-)] decreased. The[ Ca(2+)] and [ PO(4) (3-)] were independent of the ionic strength. Ba(2+) and AI(3+) ions were completely ion-exchanged with calcium ions in Hap lattice within 2 hr. The solution pH was increased by 1.1-1.8 after the dissolution of OH(-) ions on the Hap surface. In the presence of bovine serum albumin (BSA), the Hap particles dissolved slightly faster than the systems without protein. This fact was explained by a complexation of dissolved ions to functional groups of BSA. The adsorption of BSA induced a reduction of [Ca(2+)] and [ PO(4) (3-)] in the aqueous medium and minima appeared on [Ca(2+)] and [PO(4) (3-)] profiles before the BSA adsorption reached a saturation. This result suggests that the adsorption of BSA onto Hap is governed by [Ca(2+)] ions complexing to BSA molecules (binding effect) together with the operation of [Ca(2+)] ions exposing on the Hap surfaces by dissolution of OH(-) ions, so-called "C-sites". The addition of BaCl(2) and AlCl(3 )steeply increased the amounts of adsorbed BSA (n(BSA)) at the initial adsorption step by the strong binding effect of these di- and tri-valent cations between BSA and Hap. However, after eliminating these cations from the Hap surface by the ion-exchange reaction, the binding effects disappeared and n(BSA) decreased. Since the number of functional groups is small, the binding effect of the counter ions was only slightly detected for the systems with di- and trivalent ions on the adsorption systems of lysozyme (LSZ).

Design of a novel hydrogel-based intelligent system for controlled drug release.

The present work focused on the design of an assembled drug delivery system (DDS) to provide multifunctions, such as drug protection, self-regulated oscillatory release, and targeted uni-directional delivery by a bilayered self-folding gate and simple surface mucoadhesion. In this device, a pH-sensitive hydrogel together with a poly(hydroxyethyl methacrylate) (HEMA) barrier was used as a gate to control drug release. In addition, poly(HEMA) coated with poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO-PPO-PEO) surfactant was utilized to enhance mucoadhesion on the device surface. The release profiles of two model drugs, acid orange 8 (AO8) and bovine serum albumin (BSA) were studied in this assembled system, which compared with the conventional drug-entrapped carriers and enteric-coating systems. Furthermore, targeted uni-directional release was demonstrated in a side-by-side diffusion cell. In conclusion, for such an assembled device, the poly(HEMA) layer not only affects the folding direction but also serves as a barrier to protect the model drugs. The release time can be controlled by the thickness of the bilayered gate and the drug reservoir. Due to the reversible swelling behavior of poly(methyacrylic acid-g-ethylene glycol) (p(MAA-g-EG)) gels, the bilayered gate can sense the environmental pH change and achieve an oscillatory release pattern. Moreover, the local targeting and uni-directional release have been successfully demonstrated in vitro.

On the diameter and size distributions of Bovine Serum Albumin (BSA)-based microspheres.

A fluid mechanics-based correlation for the average size of Bovine Serum Albumin (BSA) microspheres, prepared using a water-in-oil emulsion technique, is presented. The correlation is formulated based on the theory of turbulent dispersion and a non-dimensional Weber number. Measured average diameters of the BSA microspheres prepared in olive oil at different stirring speeds are used to construct the correlation formula. The correlation gives good agreement with experimentally measured average diameters for a wide range of Weber numbers. This correlation is particularly useful to the pharmaceutical industry for predicting the size of encapsulated microspheres used in drug delivery prior to microsphere preparation. The effect of additives on microsphere size was also explored. The average diameter of the BSA microspheres was doubled by the addition of a bioadherent vitelline protein B solution. In addition, a Rosin-Rammler statistical distribution function is shown to accurately represent the microsphere size distribution obtained at different stirring speeds.

Release of albumin from chitosan-coated pectin beads in vitro.

The release behavior of albumin from chitosan-coated pectin beads in vitro was investigated. The factors, such as concentration of CaCl(2), molecular weight of chitosan, pH of chitosan solution, and pH of release medium, which can have a significant effect on the release behavior from the beads, were discussed in this study. The loading efficiency (LE) of albumin showed maximum value when the concentration of CaCl(2) and the weight ratio of pectin to albumin were 2 wt.% and 2, respectively. The release of albumin from pectin beads could be retarded by coating with chitosan at various pH medium. The increase of the concentration of CaCl(2) induced the decrease of albumin release for uncoated-pectin beads, but not much difference of release for coated-pectin ones. The higher molecular weight of chitosan showed less albumin release than the lower one. The release of albumin from the chitosan-coated pectin beads was dependent on pH of coating solution and release medium, which might affect the degree of swelling of pectin beads.

Development of intestinal immunoglobulin absorption and enzyme activities in neonatal pigs is diet dependent.

Uptake of colostrum just after birth is essential to stimulate intestinal growth and function, and in many species, including pigs, colostrum also provides immunological protection via the absorption of immunoglobulin G (IgG). In this study, intestinal growth, IgG absorptive capacity and enzyme activities were investigated in newborn pigs in response to different diets. Newborn piglets were bottle-fed porcine colostrum (PC), bovine colostrum (BC), porcine plasma (PP), porcine milk (PM), bovine colostrum containing porcine plasma (BCP) or a milk replacer (MR) every 3 h (15 mL/kg) for up to 2 d. Bovine serum albumin (BSA) was added to the diets as a macromolecule marker. The percentage of absorbed BSA just after birth was highest for piglets fed the PC diet (30-50%), lower for those fed the BC and BCP diets (23-30%) and lowest for the PP, PM and MR diet-fed piglets (7-20%, P < 0.05 relative to those fed colostrum). Porcine IgG was absorbed more efficiently than bovine IgG. Intestinal closure occurred earlier in MR and BCP piglets (within 12 h after birth) than in PC pigs. At 2 d of age, intestinal mucosal weight (+120% increase from birth) and villus morphology were similar in the PC, BCP and MR groups. All 3 groups also had increased aminopeptidase A activity compared with values at birth (+100% increase). Compared with PC pigs, the BCP group had higher sucrase and maltase activities (+50% and +200%, respectively) and lower aminopeptidase N activity (-50%, P < 0.05). Similarly, MR pigs showed elevated sucrase activity (+40%) and lowered maltase, lactase and aminopeptidase N activities (-20% to -50%, P < 0.05) compared with PC pigs. We conclude that porcine and bovine colostrum contain factors that stimulate the intestinal endocytotic and enzymatic capacity in newborn pigs. A milk replacer can produce normal gut growth, but may be inefficient in mediating normal macromolecule transport and disaccharidase activity. Bovine colostrum mixed with porcine plasma proteins may be a useful substitute for porcine colostrum in artificial rearing of newborn pigs.

Immobilization of hormones for drug targeting.

Biological active compounds such as insulin, heparin, progesterone and labeled-LH were entrapped in glutaraldehyde cross-linked bovine serum albumin (BSA) and human serum albumin (HAS) microspheres. Studies were carried out for their binding capacity and biodegradability using new proteolytic enzymes. Effects of proteolytic enzymes such as trypsin, chymotrypsin, papain and pronase-E on microspheres were studied in order to understand the biodegradability of the cross-linked proteins. It has been observed that labeled-LG was entrapped 60% in BSA and HAS microspheres. Labelled-LH-BSA, Labelled-LH-HAS and insulin microspheres were injected into mice and rabbits. It was observed that these cross-linked microspheres were biodegradable and the process appeared to be slow one, useful for sustained release of hormones. It was also observed that these albumin microspheres exhibit fluorescence at 495 nm.

Intestinal macromolecule absorption in the fetal pig after infusion of colostrum in utero.

The ability of the fetal pig intestine to absorb large proteins was investigated in utero. Six pregnant sows were anesthetized (Na pentobarbital) at 99-102 d of gestation (term = 115 +/- 2 d), and a catheter was inserted into the esophagus of two to three fetuses per sow. Via these catheters, sterile solutions (10.0 mL) of colostrum whey (CW, n = 5), milk whey (MW, n = 5), or amniotic fluid (AF, n = 4) were infused into the fetal pig stomachs every 6 h for 6-8 d starting on the day after surgery (d 0). Levels of IgG in the three fluids were 120, 0.5, and 0 mg/mL, respectively. During the first 2-3 d of infusion, plasma IgG levels rose rapidly in the CW fetuses (to 7.5 +/- 0.8 mg/mL), whereas IgG remained absent in plasma from MW and AF fetuses. Absorption of a macromolecule marker, BSA, was also higher when the marker was given with CW rather than with MW or AF. However, when all three treatment groups were given CW + BSA on the last experimental day (d 6-8), the mean BSA increment in the CW group was only 5-8% of that in the AF group, with intermediate values for the MW group. Neither at the beginning nor at the end of the experiment was macromolecule uptake in individual CW fetuses correlated with their cortisol level in plasma. The prenatal pig intestine is similar to the neonatal pig intestine in that colostrum stimulates both the macromolecule absorption and the cessation of macromolecule uptake (intestinal closure). However, fetal pigs have a lower protein absorptive capacity and a longer preclosure period than newborn pigs; this may be related to an immature structure and function and a slow enterocyte proliferation rate in the prenatal pig intestine.

Interaction of bovine serum albumin with the surface of a microcrystalline aluminum oxide hydroxide compound: a possible new type of phosphate adsorbent.

Aluminum hydroxide gel (ALG) has been effective for ameliorating acidosis associated with phosphatemia caused by hemodialysis. However, aluminum accumulation in the body causes severe side effects. As substitute for ALG, a new type of aluminum oxide hydroxide (tentatively named PT-A) was prepared with the hope of future clinical use. PT-A has a microcrystalline structure with a high resistance to pH change and has more phosphate-binding efficacy than ALG. It was tested for possible interaction with protein by adsorption test, zeta-potential analysis, X-ray diffraction, and scanning electron microscopy. Bovine serum albumin (BSA) was chosen as a model protein. The interaction of BSA with PT-A depended on the amount of adsorbent. Protein adsorption occurred rapidly and reached the maximal level at near neutral pHs. Phosphate adsorption was not affected by the presence of BSA, but the interaction of BSA with PT-A was significantly reduced by the presence of phosphate. Zeta-potential changes on the surface of PT-A indicated that the positively charged surface of PT-A was covered with negatively charged phosphate ions that repelled negatively charged BSA molecules. X-ray diffraction patterns indicated no observable structural alteration caused by adsorption of BSA or phosphate, and scanning electron microscopy revealed that BSA covered the outer surface of PT-A but did not cover small pores, where phosphate can freely penetrate.

Experimental arthritis in rats induced by intra-articular injection of IgE aggregates: evidence for arthritogenic role of complexed IgE.

An experimental arthritis model in the rat was used to study the arthritogenic potential of complexed IgE. IgE aggregates were produced in vitro by cross linking monoclonal rat IgE by dimethyl suberimidate and were injected into the knee joints. Animals which had not been injected and animals injected with phosphate buffered saline served as controls. The concentration of histamine in tissues, diffusion into the joint of bovine serum albumin labelled with iodine-125 injected intravenously, and the histology of the joints were studied. There was a significant decrease in the concentration of histamine in synovial tissue 8 and 24 hours after the injection of the IgE aggregates. A decreased number of stainable mast cells were found 8, 24, and 48 hours after exposure. A moderate hyperplasia of the synovial lining layer was also noted. These results provide further evidence for the arthritogenic potential of complexed IgE, especially in the initiation of arthritis through activation of mast cells.

The pharmacokinetics of, and humoral responses to, antigen delivered by microencapsulated liposomes.

The feasibility of creating a s.c. depot for sustained protein delivery with the goal of enhancing antigen immunogenicity was investigated. The depot was designed as antigen-laden liposomes of hydrogenated egg phosphatidylcholine and cholesterol (1:1 molar ratio) encapsulated in alginate-poly(L-lysine) microcapsules and evaluated using iodinated bovine serum albumin (BSA) as a model antigen. The in vivo release behavior of the liposomes and microencapsulated liposomes (MELs) was evaluated from the BSA serum concentration profiles after s.c. injection into rats and the pharmacokinetic parameters of 125I-labeled BSA appearance after s.c. or i.v. injections of BSA in saline. Maximal BSA concentrations were detected 11 h after s.c. injection in all rats. The BSA serum concentrations decreased rapidly in rats injected with BSA in saline or Freund's adjuvant and less rapidly in rats injected with BSA in liposomes or MELs. Four to 5 weeks after injection, BSA-associated radioactivity was detected only in sera of rats injected with BSA in liposomes or MELs. Fifty days after injection, 50% of the originally injected BSA was recovered form the s.c. sites of rats injected with BSA in MELs; no radioactivity was recovered from the other three groups of rats. The antigen-reactive antibody levels induced in rats immunized with BSA in MELs were 2- to 3-fold higher than those obtained in rats immunized with BSA in liposomes, saline, or Freund's adjuvant. More significantly, high antibody levels were maintained for more than 150 days after a single injection of BSA in MELs, suggesting that MELs can serve as a long-term single-dose immunization vehicle.

Tissue relaxation enhancement after intravenous administration of (ITCB-DTPA)-gadolinum conjugated albumin, an intravascular magnetic resonance imaging contrast agent.

Gadolinium-isothiocyanato-benzyl-diethylenetriamine pentaacetic acid (ITCB-DTPA-Gd), a derivative of Gd-DTPA, was multiply conjugated to bovine serum albumin (BSA). In the synthesis of BSA-(ITCB-DTPA-Gd) conjugate, none of the five carboxylate groups of DTPA is functionalized for protein-chelate linkage. The rationale for this modification is to improve the affinity for Gd3+. We obtained a high-stability constant for the complex, comparable to unbound Gd-DTPA. Also, the complex had a T1 relaxivity as high as 30.3 seconds-1mmol-1 at 29 MHz (at 24 degrees C). At this field strength, and T1 of rat blood declined 91% after injection of 300 mg/kg of BSA-(ITCB-DTPA-Gd), corresponding to a Gd dose of 0.02 mmol/kg, while at 0.86 MHz it declined 64%. The shortening of T1 in vitro of blood, as well as spleen, lungs, and kidneys, persisted for 60 minutes. Better enhancement on post-contrast magnetic resonance images of rats was obtained at 1.0 T than at 0.04 T. Tissues with rich vascularization and large venous structures were well displayed at the higher field.

Aging and endothelial barrier function in culture: effects of chronic exposure to fatty acid hydroperoxides and vitamin E.

As the endothelium ages it may become more susceptible to damage by atherogenic plasma components such as toxic lipid oxidation products. Vitamin E (vit E) might prove to be anti-atherogenic by reducing oxidative injury. This study investigated the effects of age and chronic exposure to fatty acid hydroperoxides (OFA) and/or vit E on endothelial barrier function (EBF) and cell growth characteristics. Chronic exposure to 5 microM OFA for 40 passages resulted in an age-related decrease in EBF, while supplementation of OFA-treated cultures with 25 microM vit E protected against the OFA-mediated decrease in EBF, independent of cell age. Vit E treatment alone had no significant effect on EBF relative to control cultures. No changes in growth characteristics, i.e., total DNA or protein per culture, were noted, regardless of treatment, although total DNA per culture decreased with increasing culture passage. These results suggest that chronic oxidative stress decreases EBF, predisposing the artery to infiltration by blood components and subsequent atherogenesis and that vit E delays cumulative changes in EBF related to chronic OFA exposure.