So many patients ask our team about stem cell therapies for pulmonary fibrosis (PF) that it has prompted us to write something specifically on this topic.
What are stem cells and why are they relevant to PF?
Stem cells are cells that are not yet fixed as lung, liver or skin cells and, in the right conditions, can give rise to many different tissues. Interest in stem cell therapies for PF has grown rapidly. The logic is simple: PF is a disease of failed repair. The cells responsible for regenerating the delicate air sacs of the lung become stressed, depleted and unable to recover. When repair cannot keep up with injury, the lung turns to scarring. Reversing – or even supporting – that repair system is one of the most promising frontiers in fibrotic lung disease.
Current evidence: what have clinical trials shown us
The most developed work in humans comes from carefully regulated clinical trials. The AETHER study, which infused bone-marrow–derived mesenchymal stem cells (MSCs) into people with PF, showed that the procedure is safe and feasible. MSCs are versatile stem cells which can turn into different kinds of cells in the body, such as bone, cartilage, and fat cells. Lung function still declined, as expected, but the study demonstrated that stem cell products can be delivered responsibly in a controlled clinical setting. Other early phase studies have explored different approaches, from adipose-derived stromal cells (fat-derived stem cells) delivered directly into the airways, to umbilical-cell–derived MSCs given intravenously. All share the same message: early work shows short-term safety, but no therapy has yet shown that it can reverse fibrosis or halt disease progression.
A more recent line of research, published in eBioMedicine, investigated whether the small airways’ own basal stem cells could be expanded and reintroduced into the lungs. In a first-in-human pilot involving three people with advanced idiopathic pulmonary fibrosis (IPF), the authors reported improvements in symptoms, lung function and airway structure. This work is extremely preliminary, but it raises an interesting possibility: that restoring pockets of healthy stem cells may help rebuild areas of repair that have failed.
What can we learn from elephants and whales?
This basic idea—strengthening repair by protecting or restoring the body’s regenerative cells—is something nature has perfected in other species. Elephants and whales, for example, rarely develop cancer despite having huge bodies and long lifespans. They have evolved extraordinary stem cell maintenance systems. Elephants carry many copies of anti-cancer genes, allowing damaged cells to self-destruct early before they cause harm. Whales possess exceptionally efficient DNA-repair enzymes, enabling their tissues to remain stable over decades. These animals have robust systems that keep their stem cell pools healthy for a lifetime. In humans, by contrast, the alveolar stem cell populations in the lung (especially the type II cells) are far more vulnerable to injury from smoking, air pollution, viral infections, gastro-oesophageal aspiration and metabolic stress.
How does lifestyle influence stem cell health?
Diet and lifestyle enter this story not as miracle cures, but as genuine influences on how hard our stem cells have to work. Cell damage from poor diet, chronic inflammation, high sugar exposure or obesity demands constant repair. The lungs of elephants and whales are not bombarded with processed foods, ultra-refined sugars, alcohol or indoor pollutants. Their diets are simple, natural and species-appropriate, placing minimal metabolic stress on their epithelial and immune systems. For humans, this does not translate into a “diet for IPF,” but it does remind us that whole foods, good nutrition, regular movement, good sleep and avoiding harmful substances in the air help preserve the stem cell populations we do have. Lifestyle changes can not cure IPF, but they can lessen the stress on the lungs, helping them manage the damage better.
Why are unproven overseas stem cell clinics a concern?
Against this backdrop of real science sits a more troubling trend: expensive commercial clinics outside the UK offering unproven “stem cell cures” for IPF. These treatments are unlicensed, unsupported by clinical trials and potentially dangerous. They often involve non-lung-specific cells delivered intravenously, where they cannot meaningfully repair scar tissue and may cause harm. They are fundamentally different from the controlled, transparent trials conducted in academic centres. The safest principle is that any therapy claiming to reverse fibrosis, or scarring, especially if it is only available abroad for large sums of money is almost certainly unproven. It is essential that patients discuss any new treatment with their healthcare team before travelling or paying privately.
Looking ahead – a realistic but hopeful outlook
Despite these challenges, the trajectory of scientific progress is encouraging. These early studies offer a hopeful glimpse of what regenerative medicine may eventually achieve in PF. Even in very damaged lungs, some stem cells remain functional — and with the right support, they may help promote local repair. The future will likely involve a combination of anti-scarring medications, protection of existing lung stem cells, and carefully controlled regenerative treatments based on how the body repairs itself.
It is also important to distinguish IPF research from the well-established use of stem cell transplantation in systemic sclerosis. In that condition, carefully selected patients can benefit from autologous haematopoietic stem-cell transplantation (HSCT), a treatment that works by resetting the immune system, not by repairing fibrosis. Large trials such as ASTIS, SCOT and ASSIST have shown that HSCT can help people live longer, slow down the disease, and even improve lung function – but only when done under careful, expert supervision. This success does not translate to IPF. Systemic sclerosis is driven by immune dysregulation, so an “immune reboot” changes the disease’s biology. IPF is fundamentally different: it is driven by epithelial stem cell exhaustion, ageing and repetitive injury, so rebooting immunity does not help. HSCT would be inappropriate and even dangerous in IPF. Yet, HSCT demonstrates an important principle: when stem cell science is applied in the right disease, in the right patients and in the right controlled environment, it can genuinely transform outcomes. The key is knowing when the biology fits and when it does not.
A lot more work is needed in this area but, if we continue to learn from the natural resilience of species like elephants and whales, protect our own lungs from avoidable injury and anchor our hopes in solid evidence rather than false hope, we may eventually see treatments that truly help the lungs heal and regain some of their lost function.
[Posted December 2025]