On this page
- What the reviews are reviews of
- Why the bleomycin model overstates things
- The human work that exists
- What fibrosis does
- What established treatment offers
- Why this group is targeted
- Fibrosis is not one disease
- Risks specific to this group
- Questions worth asking
- Frequently asked questions
- Requesting a medical evaluation
Pulmonary fibrosis scars the lungs progressively, and idiopathic pulmonary fibrosis carries a prognosis comparable to some cancers. That combination — serious, progressive, poorly treated — makes it heavily targeted by clinics. Stem cell therapy for pulmonary fibrosis is supported almost entirely by studies in rodents.
What the reviews are reviews of
A systematic review covers cells in animal models of pulmonary fibrosis — Mesenchymal Stromal Cells in Animal Bleomycin Pulmonary Fibrosis Models: A Systematic Review.
A meta-analysis examines vesicle preparations against fibrosis in rodents — MSC-Derived Extracellular Vesicles against Pulmonary Fibrosis of Rodent Model: A Meta-Analysis.
A further systematic review and meta-analysis covers conditioned medium — the fluid cells are grown in — in pulmonary fibrosis — Mesenchymal Stromal Cells Derived Conditioned Medium in Pulmonary Fibrosis: A Systematic Review and Meta-analysis.
Animal models. Rodent models. Bleomycin — the drug used to induce fibrosis in laboratory animals. Read the titles and the position becomes unambiguous.
Why the bleomycin model overstates things
Fibrosis is induced in a rodent by giving bleomycin, and the animal is treated shortly afterwards. The model produces inflammation followed by fibrosis over a few weeks.
Crucially, the bleomycin model partially resolves on its own. Rodents recover from it in a way humans with idiopathic pulmonary fibrosis do not, which means treatments can appear effective in the model and fail in people.
This has happened repeatedly. A long list of compounds that worked in bleomycin-treated mice did nothing in human trials, which is why respiratory researchers treat the model with caution.
That history is the single most important context for anyone being offered this treatment on the strength of animal data.
The human work that exists
A clinical investigation has examined nebulised cord-derived extracellular vesicles for pulmonary fibrosis — Clinical investigation on nebulized human umbilical cord MSC-derived extracellular vesicles for pulmonary fibrosis treatment.
That is one early study of a vesicle product delivered by inhalation. It is not cells, it is not an infusion, and it is not a phase 3 trial.
Exosome therapy covers what vesicle products are and how they differ from cells, including the standardisation problem that makes two products described the same way potentially quite different.
One early study is a reason to run more studies. It is not a basis for treatment.
What fibrosis does
Scar tissue replaces normal lung. It is stiff, it does not exchange gas, and it does not convert back into functioning lung.
The result is progressive breathlessness and declining oxygen levels. In idiopathic pulmonary fibrosis the course is usually downward, punctuated by acute exacerbations that carry high mortality.
No treatment in any category reverses established fibrosis. The realistic aim of all current treatment is to slow the rate of decline.
Any offer framed as clearing scar tissue from the lungs is describing something that does not exist.
What established treatment offers
Two antifibrotic drugs have randomised evidence for slowing lung function decline in idiopathic pulmonary fibrosis. They do not reverse it, they have significant side effects, and they are the current standard of care.
Oxygen therapy for those who need it, pulmonary rehabilitation, and treatment of reflux and other contributing factors.
Lung transplantation is the only intervention that substantially alters the outlook, for carefully selected patients, and referral should happen early rather than late.
Someone considering treatment abroad should know whether transplant assessment is still open to them, because some interventions and some delays affect eligibility.
Why this group is targeted
The prognosis is poor, the established treatments slow decline rather than stopping it, and patients are often told there is nothing more to offer. That combination produces people willing to try anything.
Breathlessness also fluctuates. A patient who rests, avoids exertion and receives attention will often feel better for a period regardless of treatment.
Oxygen saturation measured at rest is insensitive to change and is easily presented as reassuring. Walk tests and formal lung function are what actually track the disease.
The limits of current evidence covers this pattern of targeting across conditions.
Fibrosis is not one disease
Idiopathic pulmonary fibrosis is the most aggressive and the one with the worst prognosis, and it is the diagnosis of exclusion after everything else has been ruled out.
Fibrosis also follows connective tissue disease, certain drugs, radiotherapy, and long-term exposure to birds, mould and occupational dusts. Some of those are modifiable, and removing the cause changes the course.
Hypersensitivity pneumonitis in particular can improve substantially when the exposure is identified and stopped, which makes finding it worth far more than any treatment discussed here.
A proper diagnostic work-up — detailed history, high-resolution CT, sometimes biopsy, usually a multidisciplinary discussion — is what determines all of that, and it should come before anything else.
Risks specific to this group
Patients with fibrosis have limited respiratory reserve. Fever, fluid loading and any increase in oxygen demand are less easily tolerated.
Acute exacerbations of pulmonary fibrosis carry high mortality and can be precipitated by infection and by procedures. Travel and an intervention both raise that exposure.
Nebulised products carry airway-specific risks including bronchospasm and worsening oxygenation.
Flying with significant fibrosis needs assessment and often in-flight oxygen. International patients covers travel practicalities.
Questions worth asking
- Is the evidence for this from humans or from animal models?
- Am I on antifibrotic treatment, and has it been reviewed?
- Has transplant assessment been discussed, and would this affect eligibility?
- What will be measured — lung function and walk distance, or how I feel?
- Am I fit to fly, and what happens if I deteriorate abroad?
Chronic lung conditions covers the wider respiratory evidence, and the evidence levels explain this grading.
Frequently asked questions
Why is this graded preclinical?
Because the systematic reviews and meta-analyses in this area describe themselves as reviews of animal and rodent models.
What is wrong with the animal model?
The bleomycin model partially resolves on its own in rodents, so treatments can look effective there and fail in people. That has happened repeatedly.
Is there any human study?
One early clinical investigation of a nebulised vesicle product. That is not cells, not an infusion, and not a phase 3 trial.
Can lung scarring be cleared?
No treatment in any category reverses established fibrosis. Current drugs slow the rate of decline.
What should I be doing instead?
Antifibrotic treatment where indicated, oxygen if needed, pulmonary rehabilitation, and early discussion of transplant referral.
Could treatment abroad affect transplant eligibility?
It is worth asking your transplant team directly before travelling, because some interventions and some delays matter.
Requesting a medical evaluation
Nothing on this page establishes whether any treatment is appropriate for you. That needs your history, your imaging and your current medications read by a clinician. If you would like that review, send your records and we will tell you honestly whether there is anything worth discussing — including when the answer is no.
This page is general information, not medical advice, and does not create a doctor–patient relationship. Regenerative treatments discussed here are in most cases investigational. Discuss any treatment with a clinician who knows your history.