Heart, Liver & Diabetes

Summary — The heart, liver and metabolism field has seen active stem cell research since the early 2000s, including several relatively large randomised studies. In Japan, Yamaguchi University reported improved liver function measures after giving autologous bone marrow cells to patients with cirrhosis (2006), and cardiac regenerative medicine research has continued, centred on Osaka University. In acute myocardial infarction, a randomised study from Germany and elsewhere (2006) reported improved left ventricular ejection fraction, and in type 1 diabetes, a 2025 report described many patients no longer needing insulin injections after transplantation of islet cells made from stem cells. At the same time, some large studies did not meet their primary outcomes, so this field illustrates well how results change with study design.

Conditions in this field

This field includes heart failure, myocardial infarction, liver cirrhosis and diabetes. The heart, liver and pancreas are vital organs; once damaged, their function often declines progressively, with few fundamental options other than transplantation. Standard care has also advanced greatly, so it is important to confirm what additional benefit a new treatment brings on top of it.

Cells studied and approaches

• Indirect effects of bone marrow cells and mesenchymal stem cells — in myocardial infarction, heart failure and cirrhosis, bone marrow mononuclear cells or mesenchymal stem cells are given into the coronary artery, the heart wall or a vein, and researchers study how secreted factors reduce inflammation, support new blood vessels and limit fibrosis (scarring).
• Making and replacing cells — in diabetes, insulin-producing islet cells made from ES or iPS cells, and in the heart, heart muscle cells made from iPS cells, are being transplanted in research.
• Resetting the immune system — early in type 1 diabetes, autologous haematopoietic stem cell transplantation has been studied to stop the immune attack on the pancreas.

Key research results by condition

• Myocardial infarction — in the randomised, double-blind REPAIR-AMI study (2006), the group receiving bone marrow-derived cells into the coronary artery showed greater improvement in left ventricular ejection fraction and fewer major events at one year. The BAMI study (2020), intended to test mortality, did not reach its planned size and could not confirm a difference.
• Heart failure — POSEIDON (2012, 30 patients) reported reduced scar size with both autologous and allogeneic mesenchymal stem cells, and DREAM-HF (2023, more than 500 patients) did not meet its primary outcome but reported some secondary outcome results.
• Liver cirrhosis — the Yamaguchi University study (2006, 9 patients) reported improved serum albumin and Child-Pugh scores after autologous bone marrow cell infusion. The UK randomised phase 2 REALISTIC study (2018) did not find MELD score improvement with a different stem cell approach.
• Diabetes — a Brazilian team (2007) reported that most newly diagnosed type 1 patients went without insulin for a period after autologous haematopoietic stem cell transplantation. In 2025, NEJM reported that many participants were free of insulin injections at one year after transplantation of stem cell-derived islet cells. In Japan, research on iPS cell-derived islet cells is under way, centred on Kyoto University Hospital.

Background for understanding research in this field

In heart and liver research, positive results from early small studies have repeatedly not been confirmed to the same degree in large randomised studies. Whether improvements in intermediate measures such as ejection fraction or albumin translate into final outcomes such as mortality or hospitalisation must also be confirmed separately. In this field it is especially important to look at which measure was used and what the comparison group was.

Condition pages

The topics below give details for heart failure, myocardial infarction, liver cirrhosis and diabetes: overview, standard care, research approaches, reported results and how outcomes are measured.

Frequently asked questions

Q. Are there stem cell products approved for heart or liver disease?
No mesenchymal stem cell product is currently approved for heart failure, myocardial infarction or cirrhosis. In Japan, sheets made from the patient's own skeletal myoblasts received conditional, time-limited approval for severe heart failure in 2015, but that product uses muscle cells, not stem cells.

Q. What research is under way in Japan?
Yamaguchi University has continued its cirrhosis research towards cultured mesenchymal stem cells and donor cells; Osaka University has carried out clinical research on sheets of heart muscle cells made from iPS cells; and Kyoto University Hospital has carried out clinical research on iPS cell-derived islet cells.

Q. Can stem cells let people with type 1 diabetes stop insulin injections?
In a trial reported in 2025, many participants were free of insulin injections at one year, but they must keep taking immunosuppressants and long-term results are still being confirmed. It is not an approved treatment.

Q. Why do results differ between studies?
Cell types and routes, patient populations, outcome measures and the presence of a control group all differ. The condition pages describe each study's design.

How to look up clinical trial information

Ongoing and completed clinical trials can be checked on public registries. ClinicalTrials.gov, run by the U.S. National Library of Medicine, and jRCT, run by Japan's Ministry of Health, Labour and Welfare, publish each study's purpose, eligibility criteria, intervention, outcomes, institutions and status. Results are later published as journal papers, and the reference links at the bottom of this page lead to the original information. It is also worth knowing that interventions not publicly registered are difficult to verify from outside, in both design and results.

The above summarises results reported in published papers and public-agency materials. University and institute names are given to identify research sources, not to introduce or recommend any medical institution. Reported results do not mean the same effect for everyone, and the suitability of any treatment is decided by the medical team.