MORE EVIDENCE NANOPARTICLED DAMAGE DNA

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MORE EVIDENCE NANOPARTICLED DAMAGE DNA

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Nanoparticles can be found in common household items including sunscreen

and cosmetics. (7.30 Report)

Researchers in the United Kingdom have found some nanoparticles - which

can be found in common household items - can damage DNA without even

penetrating the cells.

 

 

They found the nanoparticles can indirectly damage DNA inside cells by

transmitting signals through a protective barrier of human tissue.

 

 

The stunning discovery adds to a growing body of research highlighting

proven and potential health hazards from the rapidly expanding universe of

engineered objects measured in billionths of a metre. Nanoscale products

already widely in use range from cosmetics to household cleaning products and

sporting goods. But the new findings, reported in the journal Nature

Nanotechnology, could also point to new ways in which nanotherapies might zero

in

on disease-causing tumours, say researchers.

 

 

They could even shed light on how poorly understood pathogens penetrate

into human organs.

 

 

In laboratory experiments, scientists led by Dr Charles Case of Southmead

Hospital in Bristol, grew a multi-layer 'barrier' of human cells to mimic

specialised protective tissues found in the body. For example one such

barrier separates blood from the brain. Underneath this layer, three-to-four

cells thick, they placed human fibroblast cells which play a key role in the

formation of connective and scar tissue. And on top they put nanoscale

particles of cobalt-chromium, an alloy that has long been used in the making of

hip-and-knee-replacement joints, and more recently in drug-delivery

mechanisms used inside arteries.

 

 

**As if it weren't there'**

 

 

Earlier studies had shown that direct exposure to large quantities of the

alloy could severely damage DNA is some cells and the researchers wanted to

find out how well the laboratory grown barrier would protect the

fibroblast cells below. **We never imagined that it wouldn't,** said Dr Case.

 

 

**But to our great surprise, not only did we see damage on the other side

of the barrier, we saw as much damage as if we had not had a barrier at

all.**

 

 

At first, the researchers speculated that the tiny particles, barely 30

billionth of a metre in diameter, had slipped through microscopic cracks in

the cellular blockade. But there was no sign of the alloy on the other side

and when the experiment was repeated with far larger particles, the result

was essentially the same.

 

 

**We could only conclude that the DNA damage occurred after indirect

exposure depending on a process of signalling between cells rather than the

passage of metal through the barrier,** said Dr Gevdeep Bhabra, a surgeon at

Southmead and co-author of the study. Professor Thomas Faunce from the

Australian National University in Canberra says the study is significant.

**Nano-toxicological research has focused on looking at what happens if we

put nanoparticles inside these type of cells,** said Professor Faunce.

 

 

**What [this latest research is] saying is once nanoparticles are in the

body they have a capacity to cause toxocological effects at a distance.**

 

 

Previously, Professor Faunce has expressed concern regarding the over-use

of nanoparticles in products such as nano-silver bandages and

undergarments. He says in light of this recent report any future investigation

into the

use of nanoparticles and their associated levels of toxicity may need to be

rethought. His views were echoed by the researchers themselves and experts

not involved in the study.

**What it tells me is that the precaution with which some scientists and

regulators say we should proceed is the right way to go,** said Professor

Vyvyan Howard, a pathologist at the University of Ulster who founded the

Journal of Nanotoxicology.

 

 

Prion diseases

 

 

But the newly uncovered mechanism holds promise too. " The first exciting

question is, can we deliver novel therapies across barriers without having

to cross them? " said Professor Ashley Blom, an orthopaedic surgeon and

researcher at the University of Bristol.

 

 

**There are also implications as to how nanoparticles that we all have in

our bodies might act across membranes - small particles like prions and

viruses may use some of these mechanisms.

 

 

**This opens up a whole new field of research.** Prion diseases occur when

a mutated form of the prion protein runs amok, destroying brain cells.

 

 

Testing

 

 

Professor Howard says when considering the safety of nanoparticles, one

must distinguish between medical and broader industrial applications. New

drugs are carefully tested, reducing the chances of widespread harm. And even

if nanodelivery and imaging systems turn out not to be risk-free, that does

not necessarily mean they should not be used. **Depending on the kind of

disease you have, you will accept some very nasty therapies,** he said. For

example a chemotherapy for cancer.

**But there is a world of difference between accepting a therapy under

informed consent and involuntary exposure.** He pointed out most industrial

uses are not regulated at all.**

 

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