A BREAKTHROUGH by scientists could reduce the need for animal testing while ensuring that patients receive drugs which are most effective for their individual needs.

Researchers at Heriot-Watt University in Edinburgh, who were behind the first 3D stem cell printer, have refined their machine to bring genetically-tailored drug testing regimes a step closer.

The team say they can now print off an extremely delicate form of stem cell, known as induced pluripotent stem (iPS) cells, which can be used as a genetic blueprint to generate a wide variety of tissue types including liver, heart and brain cells.

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In future, it is hoped that stem cell technology will revolutionise organ transplants by allowing patients to grow their own replacement organs or tissues from their stem cells.

However, bioengineers at Heriot-Watt believe the latest development could reduce the need for animal testing by providing patients with drugs matched to their own DNA profile.

Dr Will Shu, the professor of bioengineering who spearheaded the research, was responsible for putting together the original 3D printer capable of working with sensitive stem cells without damaging them.

The device was used to work with laboratory-grown stem cells, derived from embryonic stem cells which were harvested generations ago from four to five-day-old human embryos.

The use of iPS cells, derived from an adult donor's own adult cells - such as a skin cell - is less controversial, but more delicate.

However, the scientists at Heriot-Watt, working in collaboration with Midlothian-based Roslin Cellab, a stem cell technology company providing contract research and product development work for academic and commercial clients, have overhauled the printer so that it is now gentle enough to enable 3D printing of iPS cells.

This means the team will be able to print the cells in three dimensions without damaging their biological functions, including the cells' crucial ability grow into a variety of specialised human tissues and organs.

A report on the team’s work has been published in the IOP journal Biofabrication.

In the short term, the team wants to use the cell printing process to make miniature 3D human tissues for general testing of pharmaceutical drugs. If successful, it offers a more reliable and humane alternative to live animal testing.

Once established, specifically made tissue from each patient would enable doctors to prescribe drugs most likely to work and with fewest side effects.

It is the first study to to demonstrate that iPS stem cells can be bioprinted without harming their biological function.

Dr Shu said: “Our 3D printing process is gentle enough to do this. In this instance we showed that after printing we could turn the stem cells into liver cells.

“The ability to bioprint stem cells while either maintaining their ability to develop into all types of cells in the body, or indeed directing their differentiation into specific cell types, will pave the way for producing organoids, or tissues on demand, from patient-specific cells.

"These could then be used for animal-free drug development and personalised medicine."

Dr Jason King, of Roslin Cellab, said the innovation offered great potential for tissue engineers looking to use stem cells made from donors with specific diseases to create new human disease models.

This is already being done with some success for heart diseases and neurodegenerative diseases such as Parkinson’s.

Scotland is at the cutting edge of so-called personalised medicines, with Edinburgh University awarded £11.4 million earlier this year to grow their own biological organisms in the lab using stem cells as part of efforts to develop genetically-tailored medicines tailored.

The newly opened Queen Elizabeth University Hospital in Glasgow also houses the £20m Stratified Medicine Scotland Innovation Centre, where researchers are studying how patients genetic make up influences their response to certain drugs.