Apolipoprotein-mediated transport of nanoparticle-bound drugs across the blood-brain barrier

Recent studies have shown that drugs that are normally unable to cross the blood-brain barrier (BBB) following intravenous injection can be transported across this barrier by binding to poly(butyl cyanoacrylate) nanoparticles and coating with polysorbate 80. However, the mechanism of this transport so far was not known. In the present paper, the possible involvement of apolipoproteins in the transport of nanoparticle-bound drugs into the brain is investigated. Poly(butyl cyanoacrylate) nanoparticles loaded with the hexapeptide dalargin were coated with the apolipoproteins AII, B, CII, E, or J without or after precoating with polysorbate 80. In addition, loperamide-loaded nanoparticles were coated with apolipoprotein E alone or again after precoating with polysorbate 80. After intravenous injection to ICR mice the antinociceptive threshold was measured by the tail flick test. Furthermore, the antinociceptive threshold of polysorbate 80-coated dalargin-loaded nanoparticles was determined in ApoEtm1Unc and C57BL/6J mice. The results show that only dalargin or loperamide-loaded nanoparticles coated with polysorbate 80 and/or with apolipoprotein B or E were able to achieve an antinociceptive effect. This effect was significantly higher after polysorbate-precoating and apolipoprotein B or E-overcoating. With the apolipoprotein E-deficient ApoEtm1Unc mice the antinociceptive effect was considerably reduced in comparison to the C57BL/6J mice. These results suggest that apolipoproteins B and E are involved in the mediation of the transport of drugs bound to poly(butyl cyanoacrylate) nanoparticles across the BBB. Polysorbate 80-coated nanoparticles adsorb these apolipoproteins from the blood after injection and thus seem to mimic lipoprotein particles that could be taken up by the brain capillary endothelial cells via receptor-mediated endocytosis. Bound drugs then may be further transported into the brain by diffusion following release within the endothelial cells or, alternatively, by transcytosis.     

Direct Evidence That Polysorbate-80-Coated Poly(Butylcyanoacrylate) Nanoparticles Deliver Drugs to the CNS via Specific Mechanisms Requiring Prior Binding of Drug to the Nanoparticles

Purpose. It has recently been suggested that the poly(butylcyanoacrylate) (PBCA) nanoparticle drug delivery system has a generalized toxic effect on the blood-brain barrier (BBB) (8) and that this effect forms the basis of an apparent enhanced drug delivery to the brain. The purpose of this study is to explore more fully the mechanism by which PBCA nanoparticles can deliver drugs to the brain. Methods. Both in vivo and in vitro methods have been applied to examine the possible toxic effects of PBCA nanoparticles and polysorbate-80 on cerebral endothelial cells. Human, bovine, and rat models have been used in this study. Results. In bovine primary cerebral endothelial cells, nontoxic levels of PBCA particles and polysorbate-80 did not increase paracellular transport of sucrose and inulin in the monolayers. Electron microscopic studies confirm cell viability. In vivo studies using the antinociceptive opioid peptide dalargin showed that both empty PBCA nanoparticles and polysorbate-80 did not allow dalargin to enter the brain in quantities sufficient to cause antinociception. Only dalargin preadsorbed to PBCA nanoparticles was able to induce an antinociceptive effect in the animals. Conclusion. At concentrations of PBCA nanoparticles and polysorbate-80 that achieve significant drug delivery to the brain, there is little in vivo or in vitro evidence to suggest that a generalized toxic effect on the BBB is the primary mechanism for drug delivery to the brain. The fact that dalargin has to be preadsorbed onto nanoparticles before it is effective in inducing antinociception suggests specific mechanisms of delivery to the CNS rather than a simple disruption of the BBB allowing a diffusional drug entry.     

Correlates of memory loss and depression among myocardial infarction patients in Al-Qassim,Saudi Arabia

Background

After myocardial infarction (MI), patients have an elevated risk for depression, which has a negative impact on morbidity and mortality for patients. As depression and memory function are associated, we examined them in the context of one another. Our objectives were to determine the proportion of patients with either depression only, memory loss only, or both depression and memory loss and to examine the correlates with each outcome.

The legislation of CIS countries on the issue of genetically modified products

Genetic engineering is a fast-moving research field that produces many achievements, including genetically modified organisms, which are used during the production of food products. Recent decades have shown that scientists, policy makers and the general public cannot reach a consensus about the benefits and hazards of genetically modified food products. Opinions are so different, and both sides are so well-grounded, that it is not easy to reach a conclusion about this scientific achievement. Nevertheless, food security is one of the main objectives of the state, which is responsible for providing safe food products to its own citizens in the marketplace. This is why states are interested in reviewing these scientific achievements, in terms of the state's national interests and the security of its citizens. This article sets forth: (1) the main advantages and disadvantages of genetically modified products; (2) the role of national legislation in the control of food security; and (3) the attitude toward genetically modified products in the national legislatures of CIS countries. Taking these points into account, the authors come to the conclusion that actual Azerbaijan law is not responding to the changes, which have taken place in recent decades, in development of the world market and technological conditions in the production of food products. This provides the basis to conclude that, in actual conditions, the rights ofAzerbaijan citizens to the safety of food products are not well protected. At the end of this article, the authors make recommendations about the necessity of amendments to the legislation in their own country, towards the goal of greater control over such products in Azerbaijan.     

Fullerene-based low toxic nanocationite particles (porphyrin adducts of cyclohexyl fullerene-C(60)) to treat hypoxia-induced mitochondrial dysfunction in mammalian heart muscle

BACKGROUND: This is the first report on the targeted delivery of fullerene-based low toxic nanocationite particles (porphyrin adducts of cyclohexyl fullerene-C(60)) to treat hypoxia-induced mitochondrial dysfunction in mammalian heart muscle. METHODS: The magnetic isotope effect generated by the release of paramagnetic (25)Mg(2+) from these nanoparticles selectively stimulates the ATP overproduction in the oxygen-depleted cell. RESULTS: Because nanoparticles are membranotropic cationites, they will only release the overactivating paramagnetic cations in response to hypoxia-induced acidic shift. The resulting changes in the heart cell energy metabolism result in approximately 80% recovery of the affected myocardium in <24 h after a single injection (0.03-0.1 LD(50)). CONCLUSIONS: Pharmacokinetics and pharmacodynamics of the nanoparticles suggest their suitability for safe and efficient administration in either single or multi-injection (acute or chronic) therapeutic schemes for the prevention and treatment of clinical conditions involving myocardial hypoxia.