Kidneys are bean-shaped, fist sized organs that sit on either side of the spine under the ribcage. The kidneys are made of amazingly intricate systems of microscopic filters and draining tubules called nephrons to filter around 150 litres of blood every day. This filter and tubular system of kidneys not only remove waste products of metabolism, they also regulate fluid volume.
10% of the population worldwide is affected by chronic kidney disease (CKD), and millions die each year because they do not have access to affordable treatment. Of the 2 million people worldwide who currently receive treatment for kidney failure, the majority are only treated from 5 countries, USA, Japan, Germany, Brazil and Italy. In the other 112 countries, many cannot afford treatment, resulting in the death of over 1 million people annually from untreated kidney failure.
The only treatment available to end stage renal diseases is dialysis or renal transplantation. Dialysis requires the patient to be tied to a dialysis machine in hospital for 4 hours, 3 times a week. However, only one in 3 dialysis patients manage to live beyond five years without a transplant.
Though kidney transplant is the only realistic and established solution to this devastating disease, it is not practically possible to get a reasonably matched kidney for every patient afflicted by end stage kidney disease. In the US, 102,000 people await a transplant every year, whilst only 17,000 receive a kidney annually. Not surprisingly, this demand and deficit scenario has created a market for illegal organ trade in many parts of the world where kidneys are removed from the bodies of economically vulnerable people and trafficked for commercial purposes. The total value of a kidney on the ‘red market’ is more than $160,000, whilst donors receive about $5000. Furthermore, a patient with renal transplant will need immunosuppressants for whole of their life .
In order to match the intricacy and function of a real kidney, William Fissell, an associate professor at the Vanderbilt University medical centre, has come up with a novel idea with his team, of making an implantable bioartificial kidney – a device which mimics the role of a kidney in terms of waste, salt and water removal. The device is implantable, and small enough – about the size of a coffee cup – to fit inside the patient’s body, whilst at the same time requiring no kidneys to be removed in order to fit it in the body; instead it is inserted near the kidney and hooked to the patient’s blood supply and bladder. This will replace the demand for a dialysis or transplant among patients, therefore preventing millions of deaths from kidney failure, due to waiting times for kidney transplants.
Microchip filters in the implantable bioartificial kidney will be used to scaffold the membrane of the living kidney cells by stacking about 15 microchips – one on top of the other. They will be powered by the patient’s own heart, and can detect toxins, salts and water, helping to remove them from the blood, similar to glomerular filtration, creating a biohybrid device. They will use silicon nanotechnology, similar to what is used in the microelectronic industry. Immunoisolation is provided by the membranes on which the patients’ own kidney cells are grown, which grow well on a lab dish. Overall, the device can accurately distinguish between waste chemicals in the body, and nutrients that the body must reabsorb, and can be attached to vessels to provide permanent therapy.
The strategies and methods of this work could be relevant to development of other biohybrid organs such as bioartificial liver or bioartificial pancreas and organs-on-chips. The implantable artificial kidney project is set to be included in the FDA’s new fast-track program that will speed developments up. Human trials are expected to start this year. The artificial Kidney project team estimate that the clinical trials will be complete by the year 2020. During the clinical trials, they will be working with manufacturers to discuss and manage the details of production. Once the clinical trials are complete, the device will be immediately available for patients internationally.
It is anticipated that the device will cost no more than what current transplant maintenance costs. The real challenge lies with providing this technology to the deprived.
With the artificial kidney expected to be ready for human clinical trials this year, biohybrid kidney could be the future, followed by bio hybrid liver, pancreas, heart etc. erasing the need for organ transplantation, thus heralding a new era. I can see millions of patients with ESRD not tied to dialysis machines or dying while waiting for kidney transplantation in the near future, bringing a halt to the ‘red market’.