Astaxanthin conjugated polypyrrole nanoparticles as a multimodal agent for photo-based therapy and imaging.

Polymeric nanoparticles are emerging as promising candidates for photo-based therapy and imaging due to their versatile chemical properties and easy fabrication and functionalization. In the present study we synthesized polypyrrole nanoparticles by stabilization with astaxanthin conjugated bovine serum albumin polymer (PPy@BSA-Astx). The synthesized nanoparticles were biocompatible with MBA-MD-231 and HEK-293 cells. Interestingly, the fabricated nanoparticles produced reactive oxygen species under 808-nm laser exposure and exerted a hyperthermic effect when the power density of the laser was increased. The photodynamic efficiency of PPy@BSA-Astx was measured by DPBF assay, and it was found to generate sufficient amount of reactive radicals to kill the cells at a power density of 0.3W/cm2. In photothermal aspect, the temperature level was reached to 57°C within 5min at 1W/cm2 power density, at the concentration of 50µg/mL. The in vitro cell toxicity studies showed concentration dependent photothermal and photodynamic toxicity. Fluorescence microscopic investigation explored the cell death and intra-cellular organ destruction by photodynamic treatment. In addition, we observed a strong photoacoustic signal from a tissue mimicking phantom study of nanoparticle treated MBA-MD-231 cells. In conclusion, the fabricated PPy@BSA-Astx nanoparticles can be used as photoacoustic imaging based prognostic agents for photothermal or photodynamic treatment.

Photothermal response of superparamagnetic iron oxide nanoparticles.

BACKGROUND AND OBJECTIVE: Superparamagnetic iron oxide nanoparticles have been used as MRI contrast agents in medical imaging. The purpose of this study was to explore the photothermal response of superparamagnetic iron oxide nanoparticles for biomedical applications. STUDY DESIGN/MATERIALS AND METHODS: Absorbance, temperature increase, and optical path length change of solutions of superparamagnetic iron oxide nanoparticles, SPIO and MION, in response to a 532 nm pulsed laser irradiation were measured. RESULTS: Both SPIO and MION showed absorption at 532 nm, temperature increase, and optical path length change. SPIO and MION underwent selective heating due to absorption of laser energy (532 nm). CONCLUSION: Temperature increase and optical path length change of SPIO and MION in response to 532 nm pulsed laser irradiation demonstrate a potential application of these particles in biomedical imaging. For further study, additional experiments applying the photothermal response of SPIO and MION in tissues are required.

Prototypical antipsychotic drugs protect hippocampal neuronal cultures against cell death induced by growth medium deprivation.

BACKGROUND: Several clinical studies suggested that antipsychotic-based medications could ameliorate cognitive functions impaired in certain schizophrenic patients. Accordingly, we investigated the effects of various dopaminergic receptor antagonists--including atypical antipsychotics that are prescribed for the treatment of schizophrenia--in a model of toxicity using cultured hippocampal neurons, the hippocampus being a region of particular relevance to cognition. RESULTS: Hippocampal cell death induced by deprivation of growth medium constituents was strongly blocked by drugs including antipsychotics (10(-10)-10(-6) M) that display nM affinities for D2 and/or D4 receptors (clozapine, haloperidol, (+/-)-sulpiride, domperidone, clozapine, risperidone, chlorpromazine, (+)-butaclamol and L-741,742). These effects were shared by some caspases inhibitors and were not accompanied by inhibition of reactive oxygen species. In contrast, (-)-raclopride and remoxipride, two drugs that preferentially bind D2 over D4 receptors were ineffective, as well as the selective D3 receptor antagonist U 99194. Interestingly, (-)-raclopride (10(-6) M) was able to block the neuroprotective effect of the atypical antipsychotic clozapine (10(-6) M). CONCLUSION: Taken together, these data suggest that D2-like receptors, particularly the D4 subtype, mediate the neuroprotective effects of antipsychotic drugs possibly through a ROS-independent, caspase-dependent mechanism.

Celiprolol, a vasodilatory beta-blocker, inhibits pressure overload-induced cardiac hypertrophy and prevents the transition to heart failure via nitric oxide-dependent mechanisms in mice.

BACKGROUND: The blockade of beta-adrenergic receptors reduces both mortality and morbidity in patients with chronic heart failure, but the cellular mechanism remains unclear. Celiprolol, a selective beta(1)-blocker, was reported to stimulate the expression of endothelial NO synthase (eNOS) in the heart, and NO levels have been demonstrated to be related to myocardial hypertrophy and heart failure. Thus, we aimed to clarify whether celiprolol attenuates both myocardial hypertrophy and heart failure via the NO-signal pathway. METHODS AND RESULTS: In rat neonatal cardiac myocytes, celiprolol inhibited protein synthesis stimulated by either isoproterenol or phenylephrine, which was partially suppressed by N(G)-nitro-L-arginine methyl ester (L-NAME). Four weeks after transverse aortic constriction (TAC) in C57BL/6 male mice, the ratio of heart weight to body weight (mg/g) (8.70+/-0.42 in TAC, 6.61+/-0.44 with celiprolol 100 mg x kg(-1) x d(-1) PO, P<0.01) and the ratio of lung weight to body weight (mg/g) (10.27+/-1.08 in TAC, 7.11+/-0.70 with celiprolol 100 mg x kg(-1) x d(-1) PO, P<0.05) were lower and LV fractional shortening was higher in the celiprolol-treated groups than in the TAC group. All of these improvements were blunted by L-NAME. Celiprolol treatment significantly increased myocardial eNOS and activated phosphorylation of eNOS. Myocardial mRNA levels of natriuretic peptide precursor type B and protein inhibitor of NO synthase, which were increased in the TAC mice, were decreased in the celiprolol-treated mice. CONCLUSIONS: These findings indicated that celiprolol attenuates cardiac myocyte hypertrophy both in vitro and in vivo and halts the process leading from hypertrophy to heart failure. These effects are mediated by a selective beta1-adrenergic receptor blockade and NO-dependent pathway.

Potassium channel blockers attenuate hypoxia- and ischemia-induced neuronal death in vitro and in vivo.

BACKGROUND AND PURPOSE: In light of recent evidence suggesting that an upregulation of K+ efflux mediated by outward delayed rectifier (I(K)) channels promotes central neuronal apoptosis, we sought to test the possibility that blockers of I(K) channels might be neuroprotective against hypoxia/ischemia-induced neuronal death. METHODS: Membrane currents were recorded with the use of patch clamp recordings in cultured murine cortical neurons. Protective effects of K+ channel blockers were examined in rats subjected to transient middle cerebral artery occlusion followed by 14-day reperfusion. RESULTS: The K+ channel blocker tetraethylammonium (TEA) (5 mmol/L) selectively blocked I(K) without affecting N-methyl-D-aspartate receptor-mediated current or voltage-gated Ca2+ currents. Both TEA and a lipophilic K+ channel blocker, clofilium, attenuated neuronal apoptosis induced by hypoxia in vitro and infarct volume induced by ischemia in vivo. CONCLUSIONS: These data are consistent with the idea that K+ channel-mediated K+ efflux may contribute to ischemia-triggered apoptosis and suggest that preventing excessive K+ efflux through K+ channels may constitute a therapeutic approach for the treatment of stroke.

Beta-amyloid peptide expression is sufficient for myotube death: implications for human inclusion body myopathy.

Inclusion body myositis (sIBM) is the most common disorder of skeletal muscle in aged humans. It shares biochemical features with Alzheimer's disease, including congophilic deposits, which are immunoreactive for beta-amyloid peptide (Abeta) and C'-terminal betaAPP epitopes. However, the etiology of myofiber loss and the role of intracellular Abeta in IBM is unknown. Here we report correlative evidence for apoptotic cell death in myofibers of IBM patients that exhibit pronounced Abeta deposition. HSV-1-mediated gene transfer of Abeta(42) into cultured C2C12 myotubes resulted in a 12.6-fold increase in dUTP-labeled and condensed nuclei over nonexpressing myotubes (P < 0.05). The C'-terminal betaAPP domain C99 also induced myotube apoptosis, but to a significantly lesser extent than Abeta. Apoptosis specific to Abeta-expressing myotubes was also demonstrated through DNA fragmentation, decreased mitochondrial function and the loss of membrane phospholipid polarity. Myotubes laden with Abeta(42), but not other transgene products, developed cytoplasmic inclusions consisting of fibrillar material. Furthermore, injection of normal mouse gastrocnemius muscle with HSV-encoding Abeta cDNA resulted in TUNEL-positive myofibers with pyknotic nuclei. We conclude that Abeta is sufficient to induce apoptosis in myofibers both in vivo and in vitro and suggest it may contribute to myofiber loss and muscle dysfunction in patients with IBM.

Extracts of smokeless tobacco induce pro-inflammatory changes in cultured human vascular endothelial cells.

Habitual use of smokeless tobacco leads to accumulation of inflammatory leukocytes at the site of placement, which may contribute to tissue damage. Recruitment of leukocytes is facilitated by the endothelial lining of blood vessels, which can be activated to express adhesion molecules and to produce chemoattractants. The ability of aqueous extracts of chewing tobacco, dry snuff, and moist snuff to stimulate such changes was investigated using cultured human umbilical vein endothelial cells (HUVEC). All three extracts caused HUVEC to express the adhesion molecule E-selectin and to produce the chemokines interleukin-8 and monocyte chemoattractant protein-1. Neutrophils migrated avidly across HUVEC monolayers that had been previously exposed to the extracts, whereas migration across unstimulated monolayers was negligible. The smokeless tobacco extracts contained relatively high concentrations of bacterial lipopolysaccharide (LPS). Although LPS appeared to be the major stimulatory component in extracts of chewing tobacco, it accounted for only part of the activity found in extracts of moist and dry snuffs. These observations suggest that smokeless tobacco may induce inflammatory changes in vivo by activating endothelium in a manner that promotes recruitment of leukocytes.

[The antiatherosclerotic effect of verapamil in a cell culture of human aortic intima]. / Antiateroskleroticheskii éffekt verapamila v kul'ture kletok intimy aorty chelovoeka.

Verapamil was examined for effects on atherosclerotic manifestations in cultured human aortic intimal cells. Addition of verapamil in a concentration of 10(-6)-10(-4) M to the cultured cells isolated from aortic atherosclerotic areas led to lower cellular lipids, suppressed cell proliferation and inhibited synthesis of collagen and cholesterol esters 24 hours after incubation. Verapamil also prevented atherogenic serum-induced accumulation of cholesterol in the cells isolated from normal aortic intimal areas. No decrease in cellular cholesterol levels was observed when the cells had been incubated with verapamil in the medium containing lipid-free serum. The findings suggest that the atherosclerotic effect of verapamil, which was seen in the experiments with animals, can be determined by the action of this drug on cellular processes.