islamabad - Intermittent fasting may help combat the most common type of childhood leukaemia - acute lymphoblastic leukaemia - according to new research.

The researchers note that previous studies have suggested fasting can boost the anti-cancer effects of chemotherapy. However, the underlying mechanisms for this association have been unclear.

For their study, Dr. Zhang and colleagues set out to gain a better understanding of how fasting affects cancer cells in several mouse models of ALL.

The researchers identified one dietary restriction regimen that appeared to kill leukemia cells and halt development of both ALL subtypes.

“Strikingly, we found that in models of ALL, a regimen consisting of six cycles of 1 day of fasting followed by 1 day of feeding completely inhibited cancer development,” explains Dr. Zhang.

“Although initially cancerous, the few fluorescent cells that remained in the fasted mice after 7 weeks appeared to behave like normal cells. Mice in the ALL model group that ate normally died within 59 days, while 75 percent of the fasted mice survived more than 120 days without signs of leukaemia.”

Dr. Chengcheng Zhang

What is more, the team found that the spleens and lymph nodes of mice that were subject to intermittent fasting were comparable in size to those of normal mice. The researchers also tested the effects of fasting on mouse models of acute myeloid leukaemia (AML) - a form of leukaemia that is more common in adults - but they found it had no effect.

According to the researchers, fasting reduces levels of a hormone called leptin - known as the “satiety hormone” because it regulates appetite. Previous studies have shown that in patients with ALL, leptin receptor activity is decreased.

With this in mind, Dr. Zhang and team decided to monitor leptin levels and leptin receptor activity in the mouse models.

As expected, the researchers identified reduced leptin receptor activity in mice with ALL. However, they found that this activity increased in the mice subject to intermittent fasting.

“We found that fasting decreased the levels of leptin circulating in the bloodstream as well as decreased the leptin levels in the bone marrow,” explains Dr. Zhang.

“These effects became more pronounced with repeated cycles of fasting,” he adds. “After fasting, the rate at which the leptin levels recovered seemed to correspond to the rate at which the cancerous ALL cells were cleared from the blood.”

The researchers point out that mouse model of AML already had higher leptin receptor activity, and this activity was not affected by intermitted fasting. This, they say, might explain why fasting has no effect on this type of leukaemia.

“This study using mouse models indicates that the effects of fasting on blood cancers are type-dependent and provides a platform for identifying new targets for leukaemia treatments. We also identified a mechanism responsible for the differing response to the fasting treatment.”

Dr. Chengcheng Zhang

In future research, the team plans to search for fasting-mimicking strategies that can halt ALL development.

Because the study only tested fasting - not drugs - the researchers believe it is possible that progression to human clinical trials may be quicker.