The study led by Professors Sue Kimber and Adrian Woolf from The University of Manchester, signifies a significant milestone in the development of treatment for kidney disease . The study was published in the journal  Stem Cell Reports .

Kidney glomeruli – constituent microscopic parts of the organ- were generated from human embryonic stem cells  grown in plastic laboratory culture dishes containing a nutrient broth known as culture medium, containing molecules to promote kidney development.

They were combined with a gel like substance , which acted as natural connective tissue – and then injected as a tiny clump under the skin of mice.

After three months, an examination of the tissue revealed that nephrons: the microscopic structural and functional units of the kidney – had formed.

The new structures contained most of the constituent parts present in human nephrons – including proximal tubules, distal tubules, Bowman's capsule and Loop of Henle.

Tiny human blood vessels – known as capillaries – had developed inside the mice which nourished the new kidney structures. However, the mini-kidneys lack a large artery , and without that the organ's function will only be a fraction of normal.

So, the researchers are working with surgeries to put in an artery that will bring more blood to the new kidney. To test the functionality of the new structures, the team used Dextran.

The Dextran was tracked and detected in the new structures' tubules , demonstrating that filtrate was indeed being produced and excreted as urine.

"What is particularly exciting is that the structures were made of human cells which developed an excellent capillary blood supply, becoming linked to the vasculature of the mouse.

"Though this structure was formed from several hundred glomeruli , and humans have about a million in their kidneys – this is clearly a major advance." It is a proof of principle – but much work is yet to be done. "

Professor Woolf, said: "Worldwide, two million people are being treated with dialysis or transplantation for kidney failure , and sadly another two million years each year, unable to access these treatments.

So, researchers are tremendously excited by this discovery and they feel it is a big research milestone which may one day help patients.

However, there is a lot more to learn: Building on our generation of kidney filtration units must now turn to developing an exit route for the urine and a way to deliver this technology to diseased kidneys