Nanoparticles can get into various types of cells and accumulate there; they travel along blood and lymphatic vessels and cause oxidative stress and inflammation. Nanoparticles can cause death of laboratory animals. Russian scientists discussed how prevent possible cure-all from becoming an invisible killer.

Russian medics claim that preclinical trials of nano-pharmaceutucals should differ from that for ordinary treating agents. One of crucial steps for such trials is testing on apes, or otherwise many negative effects of nano-pharmaceutucals could not be detected. Tests of monoclonal antibody TGN1412 in Great Britain, performed on several animal species showed that only apes suffered from swelling of lymphatic nodes. Six volunteers, who participated in the tests, found themselves in very bad condition. Several minutes after TGN1412 injection, all six of them felt heavy pain in their muscles, then came convulsions, choking fits and vomit. Medics diagnosed extensive inflammatory processes in various tissues and multiple organ dysfunctions. Heavy edemas altered faces of poor volunteers beyond recognition.

Russian medics emphasize the fact that there are no appropriate toxicity studies for nano-products, despite their possible catastrophic effect. Nanoparticles may cause oxidative stress, which launches mutagenesis and leads to hereditary diseases, various cancers and developmental defects. Moreover, nano-products may damage DNA and result in atherosclerosis and carcinogenesis. According to Russian scientists, the method of preclinical trials of nano-pharmaceutucals should change significantly. Trials should be performed on mammals only, their effects require tests in various tissues, experiments should be longer and nano-particles of various size and shape should be studied. One of the most important parts of such trials is estimation of possible long-term effects from nano-pharmaceuticals.

Treating agents, which contain nano-particles, are usually suspensions with nano-containers for precise drug delivery, various creams or counterstains for diagnostics. These can be fullerenes, gold, polymer or protein particles. Russian scientists know the reason why nanomaterials behave in a different way than their chemical analogues, which consist of larger particles. Nanoparticles have significant surface curvature, and atomic bonds in them have topology, different from normal, that is why their chemical activity is also different. These structural changes cause shifts in solubility, reactive and catalytic capacity, which in its turn, produce more free radicals and active forms of oxygen. Nanoparticles can embed into cell membranes, get inside cell organelles, and affect heir functions. Moreover, nanomaterials usually bear electric charge, thus easily absorb various toxic materials and take them inside cells.

Today only 49 Russian institutions are listed in the “List of establishments and institutions, performing preclinical trials of treating agents”, however, only one farm for laboratory animals in Puschino, Moscow Region, meets all international standards. Scientists say that creating new standards of nano-drug preclinical trials is only first stage – second is reconstruction of drug test centres. Otherwise, the share of dangerous pharmaceuticals on our market will keep growing.

Source: Science & Life

Kizilova Anna