Professor Anil Dhawan, Clinical Academic Group Co-Lead – Kings College Hospital explains that adult liver cells have the potential to help children with a number of rare, inherited diseases.
Urea Cycle Defects (UCD) can lead to further
Liver problems can lead to a wide range of rare diseases in affected babies. The names of these diseases are quite technical but can include Wilson’s disease, Crigler-Najjar syndrome, familial hypercholesterolaemia, factor VII deficiency, glycogen storage disease type I, infantile Refsum’s disease, progressive familial intrahepatic cholestasis type 2 as well as a range of conditions collectively known as ‘urea cycle defects’ or UCD. Conditions described as UCD include orthnithine transcarbamase (OTC) deficiency, argininosuccinate lyase (ASL) deficiency, carbamoylphosphate synthase type 1 (CPS1) deficiency and citrullinemia.
UCD is thought to affect around one in 8,500 to 35,000 live births. These rare problems are present at birth and most will not be detected as part of routine testing for new-borns but it is usual for pregnancies to be more carefully scrutinised and managed if a sibling or close relative has previously been affected by a UCD.
Any of these unusual conditions will expose a baby to risks, which include brain damage and, left untreated, will prove fatal. The root cause of these disorders is genetic and at present cannot be corrected.
Medication and treatment has progressed over years
Historically, patients with UCDs were managed using a low protein diet to help reduce the damaging build-up of ammonia. More recent improvements to this approach have improved life expectancy, but all too often patients were left with brain damage. Today, the standard treatment is liver transplantation, an approach which presents its own challenges. Suitable donors are rare and liver transplantation is a major procedure that carries risks of its own.
These difficulties have led to the investigation of a variety of forms of ‘cell therapy’ as alternatives to transplanting entire or partial organs. One example is liver cell therapy (LCT) which involves the infusion of adult liver cells into the patient’s blood stream. LCT has advantages over an immediate liver transplant in that it is less invasive, is repeatable and is less subject to donor shortages. LCT is known as a ‘bridging therapy’ that can minimise brain damage and help control other symptoms until a suitable donor liver becomes available.
My team and I at King’s College Hospital in London have been conducting research into the infusion of adult liver cells in children with a range of inherited liver problems. We have faced many challenges in bringing the benefits of LCT to patients including selecting the most effective technique for infusing the cells, stimulating and controlling the multiplication of the infused cells, sourcing appropriate adult liver cells and then preserving them in cold storage until they are used.
Liver Cell Therapy has the potential to help more patients
Today we are able to infuse adult liver cells into the ‘hepatic sinusoids’, a particular type of blood vessel within the liver which is rich in oxygen and nutrients. The adult liver cells first become physically ‘stuck’ in smaller vessels of the young patient’s liver before migrating into the liver tissues themselves. Here they integrate with the host liver’s existing cells and can be stimulated to proliferate if required. Once in the host liver, the new cells are able to perform the functions that the patient’s liver cannot, temporarily overcoming the problem that the baby was born with.
Ultimately LCT has the potential to help a much wider range of patients including both children and adults with enzyme deficiencies, metabolic diseases, coagulation disorders and liver failure. At King’s College Hospital we are continuing our research to help those unfortunate few children who are born with inherited liver problems, including making ongoing efforts to optimise LCT, to explore other forms of cell therapy and to bring their benefits to more patients.
At present liver cell therapy is only available in the UK from King’s College Hospital, London.
