Scientists redefine how human blood is made

Toronto: Turning conventional wisdom on its head, a team of Canadian scientists has discovered a completely new view of how human blood is made.

According to them, the whole classic “textbook” view we thought we knew about blood formation doesn't actually even exist.

"Through a series of experiments, we have been able to finally resolve how different kinds of blood cells form quickly from the stem cell - the most potent blood cell in the system - and not further downstream as has been traditionally thought,” explained stem cell scientist Dr John Dick.

The research also topples the textbook view that the blood development system is stable once formed.

"Our findings show that the blood system is two-tiered and changes between early human development and adulthood,” says Dick, director of the cancer stem cell programme at the Ontario Institute for Cancer Research.

For redefining the architecture of blood development, the research team mapped the lineage potential of nearly 3,000 single cells from 33 different cell populations of stem and progenitor cells obtained from human blood samples taken at various life stages and ages.

For people with blood disorders and diseases, the potential clinical utility of the findings is significant, unlocking a distinct route to personalising therapy.

"The discovery means we will be able to understand far better a wide variety of human blood disorders and diseases - from anemia to leukemia,” Dr Dick noted.

There are also promising implications for advancing the global quest in regenerative medicine to manufacture mature cell types such as platelets or red blood cells by engineering cells.

"So in human blood formation, everything begins with the stem cell, which is the executive decision-maker quickly driving the process that replenishes blood at a daily rate that exceeds 300 billion cells,” the authors noted.

The findings were published online in the journal Science.