Nanomedicine in prostate cancer
Only millionths of a millimeter in size, the particles that were the subject of a 2008's forum on the German Association of Urology congress are. But the tiny open up completely new perspectives for the diagnosis and treatment of diseases.
Nanomedicine is a new branch of medicine that deals with the application of nanoparticles (nanoparticles). The latter consist of a few to a few thousand atoms or molecules and are so named because they usually only 1-100nm (nanometers) are large (= 1 millionth to one ten-thousandth of a millimeter). Such particles can be produced artificially as for cosmetics (liposomes), glass and ceramic coatings and paints arise in nature (eg, carbon black) or.Because of their small size, nanoparticles are easily absorbed into the body (eg also on the skin) and can also spread widely. What effect this may have, especially artificial nanoparticles, for many, still virtually unknown.
In Medicine is currently being researched extensively on the use of nanoparticles, for example for the targeted transport of active ingredients, to the surface of coating of implants, for clarity diseased cells (English molecular imaging, for example in PET using labeled iron particles), or the thermal treatment (see below) . A long-term goal is the accurate labeling of target cells using nanoparticles that are coupled with specific antibodies (English molecular targeting), so that could be distributed in the body, for example, tumor cells selectively kill without damaging other cells.
Gold particles against prostate cancer
A first approach to this is the ADONIS project, which has a novel diagnosis and therapy of prostate cancer to the destination. In this case, nanoparticles are used of size 100nm of gold as a contrast agent, which are coupled to an antibody to PSMA. PSMA (prostate-specific membrane antigen) is a molecule on the surface of normal prostate cells (and a few other cells in the body), which is formed of the more malignant prostate cells, the cancer has progressed.
PSMA is thus used here as a biomarker for the nanoparticles, which is why in the prostate, especially in the tumor strongly concentrated. Beam is now a laser light of a specific wavelength, the particles release from sound waves, which can be captured with an ultrasonic unit and pose. Together with a normal ultrasound, one obtains an accurate picture of the tumor. At higher laser power to heat the gold particles, so that the tumor cells can even kill. The bases of the method are clarified in the animal model and planned first human studies.
Thermotherapy with iron
The thermotherapy (heat treatment) of prostate cancer aims to heat up the tumor because malignant cells compared to normal temperature sensitive are either only moderately, to improve to 40-42 ° C, the effect of radiation therapy, or highly on more than 42 ° C, to kill the cells. Both can be achieved by irradiation of ultrasound, radio frequency or microwave reaches (see also HIFU , TUNA and TUMT in the lexicon as well as HIFU and RFA under Other local therapy of prostate cancer ).
Because the heating not good to be restricted to the target area and within them is often insufficient or uneven, a new method using magnetizable iron-containing nanoparticles has been developed. In a first feasibility study, 10 men were trapped with prostate cancer whose tumor had continued to grow after initial treatment in place (local recurrence). You, the particles were injected at various points predicted accurately in the prostate, similar to the pins for LDR brachytherapy (see radiotherapy of prostate cancer). Thereafter, they received six treatments with a magnetic field, each for an hour at a distance of one week.
Thus, a maximum temperature of 55 ° C and an average of 43 ° C could be achieved in 90% of the prostate tissue. The quality of life of the men was somewhat restricted only during the six-week treatment phase, and it was often in the first few weeks to moderate, but only local side effects, especially in discomfort when urinating. In eight men, the PSA level was subsequently dropped, but this only lasted about five months. The particles were still detectable after one year, so that a longer treatment would in principle be possible. For the authors, the method that is currently being further improved, thus proved to be feasible and side effects. The combination of nanoparticle thermotherapy and LDR brachytherapy thought they were promising, there were already to a study and another was activated.
In a further study the effect of empty and filled with iron carbon nanotubes on connective tissue cells and prostate cancer cells was studied. There were no serious adverse effects were. The authors concluded that iron-filled carbon nanotubes could be suitable for thermotherapy, and announced further studies on their magnetic and heat-generating properties.
Conclusion
Scientists certify nanoparticles have great potential for the diagnosis and treatment of diseases. Although about their biological properties and thus their potential, especially long-term risks is still little known, their use seems to purposes of research, particularly in cancer are warranted and promising.
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