Universal stem-cell biobanks: getting closer to the castle in the sky?
A report has revealed the number of distinct stem-cell lines required to provide adequate representation of Brazil’s genetically diverse population.
A recent report led by Antonio Carlos Campos de Carvalho of the Federal University of Rio de Janeiro (Brazil) and Marcio Lassance Martins de Oliveira of the National Institute of Cardiology, Ministry of Health (Brasília, Brazil), has modeled the number of stem-cell lines required to represent the genetic diversity of Brazil, and how such cell lines could provide coverage to other populations. This may galvanize the formation of a universal stem cell bank, which could alleviate the compatibility pressures associated with stem-cell transplants.
Biobanks are collections of human biological samples annotated with associated information that are organized in systematic ways to facilitate research. One of the major goals of stem-cell science is to establish a universal stem-cell biobank, whereby a person of any genetic makeup has access to compatible cell lines.
Stem-cell donors are difficult to match and even in the case of relatives, the probability of compatibility is low, such as in bone stem cell transplants where compatibility resides at 12% between relatives. A universal biobank could ease such pressure, yet it is unknown how many samples would be required for global coverage.
While repositories of stem-cell lines that represent populations have come about in countries such as the United Kingdom and Japan, these are restricted to genetically homogenous populations. For a universal stem-cell bank to materialize, it needs to encapsulate the diversity of all people, which makes Brazil a better candidate to explore these challenges due to its genetically diverse population. The researchers consider this to be an important factor in realizing the goal of a universal stem-cell biobank.
Using data from the Brazilian National Registry of Bone Marrow Donors, Carvalho and Oliveria’s team investigated how many cell lines would be needed to represent the genetic diversity of the Brazilian population.
Analyzing just over 4 million individuals’ bone marrow samples, they found approximately 1900 cell lines that could act as potential universal donors. The team predicted that 30, 51, 157, 267, and 559 distinct cell lines would cover 40%, 50%, 75%, 85%, and 95% of the population, respectively.
The researchers thus investigated how much coverage those universal cell lines would provide to other populations. They used the Allele Frequency Net Database, a data repository from 369 studies and over 10 million individuals worldwide, to estimate the coverage of the US population.
They found that the same 30 cell lines that provide a 40% coverage of Brazil provide coverage to 40% of Caucasians, 12% of African descendants, 25% of Alaska Natives and Native Americans, and less than 4% of the Asian population of the US.
The disparity between different populations, which have variable coverage from different universal cell lines demonstrates the need for a universal stem-cell bank, which the researchers believe could have significant contributions from Brazilian stem-cell lines.