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Posted: Jun 10th, 2012 A nanotechnology time bomb to fight cardiovascular disease ( Nanowerk News ) Atherosclerosis, resulting in a narrowing of the arteries and thedevelopment of cardiovascular disease, is the leading cause ofdeath worldwide. Until now, no treatment could target diseasedareas exclusively, in order to increase drug efficacy and reduceside effects. To help bridge this gap, a group of Swiss researchersfrom UNIGE, HUG and the University of Basel have developed averitable 'time bomb,' a treatment that can recognize the diseasedareas and treat only them. In Switzerland, more than 20,000 people (37% of all deaths) die ofcardiovascular disease caused by atherosclerosis each year.Treatment options are currently available to people who suffer fromthe disease but no drug can target solely the diseased areas, oftenleading to generalized side effects. Intravenous injection of avasodilator (a substance that dilates blood vessels), such asnitroglycerin, dilates both the diseased vessels and the rest ofour arteries. Blood pressure can thus drop, which would limit thedesired increased blood flow generated by vasodilatation ofdiseased vessels and needed for example during a heart attack. In order to increase the effectiveness of treatments againstatherosclerosis and to reduce side effects, a team of researchersfrom UNIGE, HUG and the University of Basel have developednanocontainers having the ability to release their vasodilatorcontent exclusively to diseased areas (see paper in Nature Nanotechnology : "Shear-stress sensitive lenticular vesicles for targeted drugdelivery" ). The lens-shaped nanocontainer (100-200nm). Nanotechnology in medicine Though no biomarker specific to atherosclerosis has beenidentified, there is a physical phenomenon inherent to stenosis(the narrowing of blood vessels) known as shear stress. This forceresults from fluctuations in blood flow induced by the narrowing ofthe artery and runs parallel to the flow of blood. It is by makinguse of this phenomenon that the team of researchers has developed averitable "time bomb", a nanocontainer which, under pressure fromthe shear stress in stenosed arteries, will release its vasodilatorcontents. By rearranging the structure of certain molecules (phospholipids)in classic nanocontainers such as liposome, scientists were able togive them a lenticular shape as opposed to the normal sphericalshape. In the form of a lens, the nanocontainer then moves throughthe healthy arteries without breaking. This new nanocontainer isperfectly stable, except when subjected to the shear stress ofstenosed arteries. And that's exactly the intention of thistechnological advance. The vasodilator content is distributed onlyto the stenotic arteries, significantly increasing the efficacy ofthe treatment and reducing side effects. "In brief, we exploited apreviously unexplored aspect of an existing technology. Thisresearch offers new perspectives in the treatment of patients withcardiovascular disease," explains Andreas Zumbuehl from theDepartment of Organic Chemistry at UNIGE. "Nanomedicine is a discipline stemming from general nanoscience butwhich orients itself towards medical research. Theinterdisciplinary collaboration between chemistry, physics, basicscience and clinical medicine in a highly technical environmentcould lead to a new era of research," states Till Saxer of theCardiology and General Internal Medicine Departments at HUG. "The nano component is present in all disciplines, but the mostinteresting aspect of nanomedicine is its overview allowing thedevelopment of clinical products that integrate this global medicalpoint of view from the earliest onset of research projects," statesBert M ler, Director of the Biomaterials Science Centre (BMC) atBasel. When chemistry gets involved How did scientists manage to change the shape of the nanocontainersso that they resemble a lens? By rearranging the structure ofmolecules, chemists at UNIGE replaced the ester bond that links thetwo parts of the phospholipid (head and tail), with an amide bond,an organic compound that promotes interaction among phospholipids.Once modified, the molecules are hydrated then heated to form aliquid sphere which will relax to solidify in the form of a lensupon cooling. The researchers then modelled the cardiovascular system usingpolymer tubes blocked to varying degrees to represent healthy andstenotic arteries. Next, an artificial extracardiac pump wasconnected to these arteries in order to reproduce the shear stressinduced by the narrowing of the vessels. The nanocontainer wasinjected into the system and samples were taken from both healthyand stenosed areas. It turns out that the active drug was found inhigher concentrations in diseased areas than in non-diseased areasand that the concentrations there were significantly greater thanif the drug had been distributed in a homogenous manner. I am an expert from faderndfilter.com, while we provides the quality product, such as China Digital Camera Screen Protectors , FOTGA DP500 Manufacturer, Fader ND Filter,and more.
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