From left to right: Dr Steve Oh, Dr Alan Lam and Dr Benoit Malleret
Since 1818, life-saving transfusions have relied on blood donations. This practice is increasingly difficult to sustain. Due to epidemic infectious diseases, aging and lower birth rates, the pool of desirable donors is declining rapidly. Five years ago, we at A*STAR sought to find a sustainable solution to manufacture off-the-shelf blood by leveraging the powerful capabilities of stem cells. We had previously uncovered ways to make red blood cells from stem cells of universal donors. This means our red blood cell product can be transfused into any recipient without the need to match blood type. Now, we have invented and patented a technology platform to mass-produce these stem cells and guide them through 4 complex stages over 5 to 6 weeks resulting in high concentrations of red blood cells in a bioreactor1,2.
The World Health Organisation reports more than 118 million blood donations globally each year [link]. In the United States, collection centres report up to 40% decrease in donations over the last decade. In Singapore, the Health Sciences Authority reports less than 76,000 donors in 2019; hence on average a donor must donate more than once a year to meet Singapore’s annual demand of more than 118,000 units of blood [link]. During Circuit Breaker, Singapore’s blood supply fell to critical levels, indicating the need for resilience in our blood supply [link]. While matching blood type remains an operational challenge, transfusion-transmitted infection is a rising clinical risk as new bloodborne pathogens [link] are not tested for in donated blood to keep transfusions affordable [link]. Therefore, manufacturing blood using stem cells presents a paradigm shift that can be sustainable. Per-donor testing will be replaced by per-lot testing that can benefit from economy of scale. By using cells from universal donors, we remove the barrier of blood type matching. With this technology, Singapore can potentially build an additional route to meet not only its own demand but also other countries’ demands, thereby creating good jobs for Singaporeans.
Researchers at the Institute of Molecular & Cell Biology, led by Dr. Jonathan Loh, sourced for human donors who are O-negative and Rhesus-negative, as their blood is suitable for transfusion to recipients of all blood types. Dr. Loh’s team reprogrammed these cells to make induced pluripotent stem cells (iPSC). Under Dr. Steve Oh’s leadership, researchers at the Bioprocessing Technology Institute used microcarriers to expand the iPSCs, induce them to mesodermal and haematopoietic progenitors, direct them to proliferate at high densities to erythroblasts, mature them to reticulocytes, and finally form enucleated red blood cells in suspension culture. Lead author and researcher Dr. Jaichandran Sivalingam, now at Tessa Therapeutics, optimized the bioprocess to enable scale-up of red blood cell biomanufacturing. Dr. Benoit Malleret and Prof. Laurent Renia from the Singapore Immunology Network extensively characterised the red blood cells and demonstrated their comparability to donated blood. Some features such as haemoglobin content outperformed donated blood. This multi-disciplinary and multi-institutional team at A*STAR is actively exploring commercialisation opportunities with industry partners.
hiPSC derived erythroblasts that form enucleated red blood cells (left). Enlarged red blood cell (right).
Pellets of red blood cells from three replicates of bioreactor cultures (left). Comparison of gene expression between hiPSC and adult blood shows minimal differences (right).
1. A scalable suspension culture platform for generating high-density cultures of universal red blood cells from human induced pluripotent stem cells. J. Sivalingam, Y. SuE, Z.R. Lim, A.T.L. Lam, A.P. Lee, H.L. Lim, H.Y. Chen, H.K. Tan, T. Warrier, J.W. Hang, N.B. Nazir, A.H.M. Tan, L. Renia, Y.H. Loh, S. Reuveny, B. Malleret and S.K.W. Oh. Stem Cell Reports. 2020 Nov. 27, S2213-6711(20)3045602.
2. Improved erythroid differentiation of multiple O-negative human pluripotent stem cell lines in microcarrier culture by modulation of Wnt/& [beta]-Catenin signaling. Jaichandran Sivalingam, Hong Yu CHEN, YANG Binxia, Lim Zhong Ri, Alan Lam Tin Lun, Woo Tsung Liang, Allen Kuan-Liang Chen, Shaul Reuveny, Yuin Han LOH, Steve Oh. Haematologica 2018 Jul; 103(7):e279-e283
3. Review: In vitro generation of red blood cells for transfusion medicine: Progress, prospects and challenges. Esmond Lee, Jaichandran Sivalingam, Zhong Ri Lim, Gloryn Chia, Low Gin Shi, Mackenna Roberts, Yuin-Han Loh, Shaul Reuveny, Steve Kah Weng Oh. Biotechnology Advances 2018 Dec; 36(8):2118-2128.