Nanoparticles Can Cause Lung Damage, But It Can Be Blocked
In a bit a good news / bad news regarding nanoparticles, Chinese researchers have discovered that a class of nanoparticles being widely developed in medicine cause lung damage (autophagic cell death). They have also shown that the use of an autophagy inhibitor can prevent the cell death counteracting the nanoparticle-induced lung damage.
The class of nanoparticles is ployamidoamine dendrimers (PAMAMs). The researchers have published their study in the June 11 online issue of the Journal of Molecular Cell Biology.
Nanotechnology has increasing become important since 1984 when German scientists developed the first nanomaterial. Nanomaterials are now used in a variety of products, including sporting goods, cosmetics and electronics. Many research scientists are trying to develop ways to use nanoparticles to improve the effectiveness of drugs and gene therapy. They are trying to do this by using the nanoparticles/technology in delivery of the drugs to selective parts or tissues in the body thereby reducing damage to healthy tissues. The US Food and Drug Administration has approved some first generation nanodrugs. These include Abraxane, a nanoformulation of the anti-cancer chemotherapy paclitaxel.
Lung damage is the chief human toxicity concern surrounding nanotechnology and the production of these extremely small particles. In this recently published study, the researchers have shown that several types of PAMAMs killed human lung cells in the lab. The researchers found that the particles triggered autophagic cell death through the Akt-TSC2-mTOR signaling pathway. Autophagy is a process that degrades damaged materials in a cell and plays a normal part in cell growth and renewal, but scientists have found that sometimes an overactivity of this destruction process leads to cell death.
The researchers also found that treating the cells with an autophagy inhibitor known as 3MA significantly inhibited the process, increasing the number of cells that survived exposure to the nanoparticles.
PAMAM Nanoparticles Promote Acute Lung Injury by Inducing Autophagic Cell Death through the Akt-TSC2-mTOR Signaling Pathway; Journal of Molecular Cell Biology Advance Access published online on June 10, 2009 (doi:10.1093/jmcb/mjp002)