alveoli

Endothelial cell treatment reverses lung damage in mice with emphysema

/ Yimy Villa / 1 Comment

Emphysema is a condition that causes damage to the alveoli, the air sacs in your lungs. The walls of the damaged air sacs become stretched out and cause your lungs to get bigger. This makes it harder to move your air in and out. It is the most common form of the condition known as chronic obstructive pulmonary disease (COPD) and is typically triggered by long-term cigarette smoking. Estimates show that approximately 200 million people around the world are affected. Unfortunately, there is no cure for this disease of the lungs.

A study conducted by researchers at Weill Cornell Medicine and NewYork-Presbyterian found that specialized endothelial cells may hold the key to treating emphysema. Endothelial cells line the inner surface of blood vessels and have been shown to play an important role in protecting and restoring the health of key organs. Specifically, lung endothelial cells line the inner surface of the lung’s network of blood vessels.

As part of their research, the team studied lung tissue from human emphysema patients while also looking at lung issue from mice with an induced form of the disease. What they found that was that changes in the activity of certain genes in lung endothelial cells and the loss of those cells was associated with decreased lung function and other indicators of emphysema progression.

The researchers then infused mice with induced emphysema with healthy lung endothelial cells from genetically identical mice and the results were astounding. The team showed that they could prevent and/or reverse most of the lung damage that was seen in untreated mice. By contrast, injecting other cell types, including endothelial cells from other tissues, did not have the same effect.

The team believes that this treatment effect might have to do with differences in the molecules secreted by diseased versus healthy lung endothelial cells. To back up this claim, they found that lung endothelial cells in both humans and mice with emphysema showed sharp increases in production of LRG1, a molecule that promotes new blood vessel growth that has been linked to retinal and kidney diseases as well as some cancers. Additionally, when the researchers deleted the gene for LRG1 from lung endothelial cells in mice, the lungs were largely protected from the lung damage of induced emphysema, much as they had been by the endothelial cell therapy.

In a news release from Cornell, Dr. Alexandra Racanelli, a co-first author on this study and an instructor of medicine in the Division of Pulmonary and Critical Care Medicine at Weill Cornell Medicine and a pulmonologist at NewYork-Presbyterian/Weill Cornell Medical Center, had this to say about the results.

“Taken together, our data strongly suggest the critical role of endothelial cell function in mediating the pathogenesis of COPD/emphysema. Targeting endothelial cell biology by administering healthy lung endothelial cells and/or inhibiting the LRG1 pathway may therefore represent strategies of immense potential for the treatment of patients with advanced COPD or emphysema.”

The full study was published in the Journal of Experimental Medicine.

‘Mini lung’ model shows scientists early stages of new coronavirus infection

/ Yimy Villa / 1 Comment
Representative image of three-dimensional human lung alveolar organoid showing alveolar stem cell marker, HTII-280 (red) and SARS-CoV-2 entry protein, ACE2 (green)
Image Credit: Jeonghwan Youk, Taewoo Kim, and Seon Pyo Hong

The development of organoid modeling has significantly expanded our understanding of human organs and the diseases that can affect them. For those unfamiliar with the term, an organoid is a miniaturized, simplified version of an organ produced that is also three dimensional.

Recently, scientists from the University of Cambridge and the Korea Advanced Institute Science and Technology (KAIST) were able to develop ‘mini lungs’ from donated tissue and use them to uncover the mechanisms behind the new coronavirus infection and the early immune response in the lungs.

SARS-CoV-2, the name of the coronavirus that causes COVID-19, first appears in the alveoli, which are tiny air sacs in the lungs that take up the oxygen we breathe and exchange it with carbon dioxide.

To better understand how SARS-CoV-2 infects the lungs and causes COVID-19, the team used donated tissue to extract a specific type of lung cell. They then reprogrammed these cells to an earlier stem cell-like state and used them to grow the lung organoids.

The team then infected the ‘mini lungs’ with a strain of SARS-CoV-2 taken from a patient in South Korea who was diagnosed with COVID-19 after traveling to Wuhan, China.

Within the newly infected lung organoids, the team observed that the virus began to replicate rapidly, reaching full cellular infection in just six hours. Replication allows the virus to spread the infection throughout the body to other cells and tissue. The infected cells also began to produce interferons, which are proteins that act as warning signals to healthy cells, telling them to activate their antiviral defenses. After two days, the interferons triggered an immune response and the cells started fighting back against infection. Two and a half days after infection, some of the alveolar cells began to disintegrate, leading to cell death and damage to the lung tissue.

In a news release, Dr. Joo-Hyeon Lee, co-senior author of this study, elaborates on how he hopes this study can help more vulnerable sections of the population.

“We hope to use our technique to grow these 3D models from cells of patients who are particularly vulnerable to infection, such as the elderly or people with diseased lungs, and find out what happens to their tissue.”

The complete study was published in Cell Stem Cell.

CIRM has funded two discovery stage research projects that use lung organoids to look at potential treatments for COVID-19. One is being conducted by Dr. Brigitte Gomperts at UCLA and the other by Dr. Evan Snyder at the Sanford Burnham Prebys Medical Discovery Institute.