Tag: idiopathic pulmonary fibrosis

Categories : New Compounds and Treatments Respiratory DiseasesTags :

Pulmonary Fibrosis has no Cure: Could a Cancer Drug Hold the Answer?

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Researchers at Tulane University have identified a potential new way to treat idiopathic pulmonary fibrosis (IPF), a deadly and currently incurable lung disease that affects more than 3 million people worldwide.

IPF is rapidly progressive and causes scarring in the lungs, making it difficult to breathe. Approximately 50% of patients die within three years of diagnosis, and current treatments can only slow the disease – not stop or reverse it. 

In a study published in the Journal of Clinical Investigation, Tulane scientists found that an FDA-approved cancer drug may help the immune system clear out the damaged cells that cause the lung scarring, potentially restoring lung function in patients with the disease.

In healthy lungs, specialised cells called fibroblasts help repair lung tissue. But in people with IPF, some fibroblasts and nearby epithelial cells stop functioning properly. These so-called “senescent” cells no longer divide or die as they should. Instead, they build up and contribute to stiff, scarred lungs.

Tulane researchers discovered that these senescent cells appear to accumulate when the immune system’s natural ability to remove them is blocked. The culprit: a protein called CTLA4, which acts as an emergency brake on immune system activity.

By using ipilimumab — an immunotherapy drug currently used to treat various cancers — the researchers were able to block CTLA4 in mice. This released the “brakes” on certain immune cells called T cells, reactivating their ability to clear out the senescent fibroblasts. As a result, the mice showed significantly improved lung tissue regeneration and reduced scarring.

“The CTLA4 protein normally functions to prevent excessive inflammation by blocking overactive T cells,” said senior author Dr. Victor Thannickal, professor and Harry B. Greenberg Chair of Medicine at Tulane University’s John W. Deming Department of Medicine. “Too much of this ‘blocker protein’ may result in losing the ‘good’ inflammation that is needed to remove senescent cells. What we’re doing is blocking the blocker.”

The researchers zeroed in on CTLA4 as a potential therapeutic target when they analyzed both human and mouse IPF lung tissue and found unusually high levels of CTLA4 on the T cells in the areas where scarring was most prevalent.

Mice that received ipilimumab showed significantly improved lung repair ability and recovered faster than mice that did not receive the drug. 

“This opens up an entirely new direction for potential treatment of IPF,” said lead author Santu Yadav, PhD, assistant professor of medicine at the Tulane University School of Medicine. “Instead of using drugs to kill senescent cells, we are re-activating our own immune system to clear them out.”

More research is needed to determine the efficacy of drugs that target CTLA4 or other so-called “checkpoint proteins” to rejuvenate the immune system. A primary concern is determining a safe dosing strategy that allows for the immune system to attack senescent cells without causing harmful levels of inflammation. 

IPF is a disease of aging and is rarely seen before age 50. These findings also offer hope that this approach could work for other similar aging related diseases. 

“If it works in IPF, this immune rejuvenating approach to treatment may be effective in other diseases such as Alzheimer’s or cardiovascular diseases in which senescent cells are known to accumulate,” Thannickal said. “Can the right drug activate T cells in a way that clears senescent cells without causing collateral damage? If so, we may be closer to combating many aging related diseases and perhaps even aging itself.” 

Source: Tulane University

Categories : Respiratory DiseasesTags :

Immune Cell Networks Found to be Driving Idiopathic Pulmonary Fibrosis

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Photo by Robina Weermeijer on Unsplash

Rutgers Health researchers have discovered that networks of misplaced immune cells drive an aggressive lung disease, potentially opening a path to new treatments for a condition that kills 80% of patients within a decade.

Idiopathic pulmonary fibrosis (IPF) scars lung tissue and makes breathing increasingly difficult until patients can’t get enough oxygen. Available drugs provide minimal benefit. Lung transplantation works for some patients, but transplants have a 50% five-year mortality rate.

This study in the European Respiratory Journal used advanced spatial mapping techniques to compare healthy lung tissues and tissues from patients with fatal IPF. The researchers discovered that disease-scarred lung tissue abounds in plasma cells – specialised immune cells that typically reside in bone marrow and produce antibodies.

“What we found most striking in this study is that all the fibrotic regions of IPF patients’ lungs are covered by antibody-producing plasma cells,” Qi Yang, an associate paediatrics professor at Rutgers and a senior author of the study. “In normal lungs, there are almost no plasma cells. But in IPF patients, the lungs are full of them.”

The researchers identified previously unknown cellular networks orchestrating this abnormal immune response. They discovered novel mural cells wrapping around blood vessels and producing signal proteins that organize immune responses. They also found unique fibroblasts secreting a protein that attracts plasma cells to damaged areas.

“This particular type of fibroblast has never been described before,” said Reynold Panettieri, director of the Rutgers Institute for Translational Medicine and Science and a senior author of the study. “People have shown that fibroblasts are the cell types responsible for scarring – in the skin, the lungs and the brain – but this particular type of fibroblast seems unique to the lung.”

Having found the plasma cells in lung tissue taken from people who died of IPF, the team began using live mice to see if reducing plasma in the lungs slowed disease formation. This work demonstrated that blocking signaling pathways reduced plasma cell accumulation and alleviated lung scarring. Targeting these same signaling pathways may thus prove an effective disease treatment in humans, the researchers said.

The research is particularly promising because drugs targeting plasma cells already exist. Medications used to treat multiple myeloma, a plasma cell cancer, could potentially be repurposed to treat IPF.

“If the plasma cells are really making the bad antibodies, I assume we may have to get rid of them,” said Yang, a member of the Institute for Translational Medicine and Science. “Otherwise, patients will keep making these antibodies that drive the disease.”

Previous studies have shown that IPF patients have heightened antibody responses and elevated lung antibody levels. The new research explains the origin of these antibodies and reveals how abnormal antibody-producing cells accumulate in the lungs.

The researchers said the antibodies may drive tissue damage through several mechanisms. Their data suggest that antibody-antigen complexes stimulate the production of transforming growth factor-beta from pulmonary macrophages, thus promoting fibrosis.

“Now that we have a target, a cell, a unique cell that Dr Yang has identified and phenotyped, we’re optimistic that we could affect that cell and not other fibroblasts that are important in normal injury repair response,” Panettieri said.

For patients with IPF, the findings offer hope of new treatments for a debilitating condition with limited therapeutic options. The disease typically affects men over 60 years of age, with most patients dying within five years of diagnosis.

The next steps for the research team include determining whether the plasma cells are producing autoantibodies against healthy tissues and further investigating how fibroblasts and mural cells develop their abnormal properties in IPF.

“Our research suggests that IPF might have a strong autoimmune link,” Yang said.

Source: Rutgers University