The search for a cure for blood cancers has received a boost with new research by Singapore scientists shedding light on how stem cells can be more effectively used to treat diseases such as leukaemia.

The five researchers are from the National Cancer Centre Singapore, the National University of Singapore (NUS), Duke-NUS Medical School, and the Singapore General Hospital (SGH). The team said it discovered a laboratory-synthesised chemical substance that can be used to increase the number of stem cells harvested from umbilical cords. It said this will help overcome a current challenge of cell levels being too low to help patients recover quickly.

To help restore healthy bone marrow in patients with leukaemia, for example, stem cells and blood-forming progenitor cells are injected into the patient. After entering the bloodstream, the stem cells travel to the bone marrow and start to make new blood cells. This helps stimulate new bone marrow growth and restores the immune system.

These cells are usually harvested from either the umbilical cord, peripheral blood (bloodstream) or bone marrow.

But there are challenges. Because harvesting bone marrow stem cells involves an invasive procedure, there are few donors. As for peripheral blood, the cells collected usually have more immune cells. These cells could in turn attack the patient and cause side effects.

Umbilical cord, however, is promising as it contains the highest number of undifferentiated stem cells. But their numbers are usually not high enough for rapid recovery in adult patients.

This results in the longest recovery time of more than 25 days in a patient who has undergone umbilical cord blood transplant, compared to the 14 days of recovery time from a peripheral blood transplant, and an 18-day recovery period from bone marrow transplant.

The researchers found a way to increase the numbers of such blood-forming stem cells from umbilical cord blood using a laboratory-synthesised substance called C7, synthesised in the NUS Department of Pharmacy.

They found that this substance is able to expand the number of blood-forming stem cells in the umbilical cord through cell culture.

Said Prof Hwang, who is also a senior consultant with the department of haematology at SGH: “There are patients who are unable to find a fully matched bone marrow or peripheral blood stem cells. For these patients, umbilical cord blood is the only source of grafts.”

But under present conditions, low cell numbers from treatments using umbilical cord blood result in long recovery periods.

“Expanded umbilical cord blood (using C7) would be a life-saving option,” he said. The researchers said trials involving mice were encouraging, as it showed that the stem cells increased in numbers over time, and did not die.

Clinical trials are expected to start in mid-2019. With support from industrial partners, Prof Hwang said he is optimistic that stem cell treatment could be available to patients within the next five years.