COVID-19 has wide-ranging and dramatic impacts on the entire body. However, the disease affects the lungs more than any other system. Understanding what it does to the lungs, the potential for lung damage, and the possible options for lung repair are important for patients struggling with the disease, as well as for their family members.
What Does COVID-19 Do to the Lungs?
The novel coronavirus causes COVID-19, which is primarily a respiratory illness, although it can affect other systems in the body. The virus begins by infecting soft tissues in the eyes, the nose, the mouth, and the throat. From there, it replicates itself, moving farther and farther downward. The next step is the upper respiratory system, where it can cause symptoms like a sore throat, coughing, and shortness of breath.
The disease often moves into both lungs, and then continues its way into the lower respiratory tract. Here, symptoms worsen as the immune system redoubles its efforts to halt the invader. Fluid can build up within the lower lungs, as can debris from dead and dying viral cells.
From this point, the disease continues to develop. COVID-19 pneumonia is very common, particularly with older patients and those with underlying medical conditions. It can progress to acute respiratory distress syndrome (ARDS), sepsis, and superinfection, according to Johns Hopkins.
Long-Term Effects of COVID-19 on the Lungs
With other diseases, patients can look forward to eventually recovering completely in many cases. Even pneumonia can clear up completely. However, with COVID-19, many patients are struggling with long-term effects, and possibly even permanent damage. According to Banner Health, some of the long-lasting side effects of COVID-19 include limited lung capacity, psychiatric issues like PTSD and depression, kidney complications, and reduced overall physical and mental health due to limited lung and organ function.
Healthline provides even more insight into the wide-ranging, long-term effects of COVID-19.
"A 20-year-old COVID-19 survivor in Chicago was the recipient of a new set of lungs due to a lung transplant that was necessary to treat a condition now being called post-COVID fibrosis."
COVID fibrosis is a condition in which holes develop within the lungs. It’s also called post-ARDS fibrosis. The damage is irreversible and can dramatically reduce lung function and capacity, creating severe shortness of breath and forcing the patient to use supplemental oxygen. While doctors are unsure of the cause of post-COVID fibrosis, some factors include blood clotting within the lungs, as well as the debris created by the body’s own immune system. Both cause lung tissue to die, creating holes in the lungs.
What Treatment Options Exist for Lung Damage from COVID-19?
Currently, there are no treatment options for COVID-19 related lung damage. Severely damaged lungs may require replacement through a transplant, as in the case of the Chicago patient discussed above. In other cases, damage may heal slowly over time, although some damage may be permanent.
However, stem cell therapy is a promising option that may be able to not only heal damage but to regenerate lung tissue. Many stem cell trials are currently underway involving COVID-19 patients to determine the efficacy and value of this treatment.
One study, published in the journal Stem Cells Translational Medicine, noted
"Since there are no effective preventive or curative therapies currently, MSC therapy (MSCT) has emerged as a possible candidate despite the lack of preclinical data of MSCs for COVID‐19. Interestingly, MSCT preclinical data specifically on immune/inflammatory disorders of the lungs were among the earliest to be reported in 2003, with the first clinical use of MSCT for graft‐vs‐host disease reported in 2004.
Since these first reports, preclinical data showing beneficial effects of MSC immunomodulation have accumulated substantially, and as a consequence, over a third of MSCT clinical trials now target immune/inflammatory diseases. There is much preclinical evidence for MSCT in noninfectious—including chronic obstructive pulmonary disease, asthma, and idiopathic pulmonary fibrosis—as well as infectious bacterial immune/inflammatory lung disorders, with data generally demonstrating therapeutic effects."
A second study, this one published in the journal Stem Cell Research, notes the
"possible involvement of ACE2+ stem/progenitor cells from both the upper and lower respiratory tracts in coronavirus infection. Viral infection-associated acute respiratory distress syndrome and acute lung injury occur because of dysregulation of the immune response. Mesenchymal stem cells appear to be a promising cell therapy given that they favorably modulate the immune response to reduce lung injury.
The use of exogenous stem cells may lead to lung repair. Therefore, intervention by transplantation of exogenous stem cells may be required to replace, repair, remodel, and regenerate lung tissue in survivors infected with coronavirus. Ultimately, vaccines, natural killer cells and induced-pluripotent stem cell-derived virus-specific cytotoxic T lymphocytes may offer off-the-shelf therapeutics for preventing coronavirus reemergence."
Another study, this one much larger, is being spearheaded by Dr. Michael Matthay at UCSF. The study will involve 120 patients and will require a full year for completion. In all, 60 patients will receive stem cell therapy and the other 60 will receive a placebo. Dr. Matthay hopes to help heal lung injuries due to COVID-19, improve patients’ ability to breathe, and also anticipates seeing at least some degree of tissue regeneration and lung repair.
Stem Cell Type
It’s important to note that many of these studies involve one of two types of stem cells – autologous stem cells sourced from the patient’s body, and allogeneic stem cells. Allogeneic stem cells, particularly those sourced from umbilical cord blood, offer much greater regenerative capabilities, are more energetic, and have no accumulated damage (which can trigger a negative immune system response).
Patients are also urged to remember that because the FDA has not approved any stem cell treatment in the United States, all such therapies are deemed experimental.