Alpha-1 antitrypsin deficiency (AATD) is an inherited deadly genetic disorder affecting the liver and the lungs. Statistics say, one in every 3000 individuals worldwide is known to have this disorder. Although there are ways to treat AATD, the treatments are often expensive and work towards slowing down disease progression, rather than curing it. In a recent study, scientists at the National Institute of Immunology, Delhi, have shown that bone marrow stem cell therapy might be a viable option to cure AATD, with promising results.
The liver cells in our body secrete a protein called alpha-1-antitrypsin (AAT) into the bloodstream, from where it travels to the lungs to protect them and ensure proper functioning of the lungs. Without enough AAT, the lungs could be damaged, resulting in breathing difficulties. In case of an individual with AATD, either one or both the AAT genes are mutated or damaged. This results in a mutant AAT protein that gets accumulated in the liver cells, instead of being secreted into the blood, hence affecting both the liver and the lungs. In severe cases, AATD can lead to liver cancer and chronic asthma.
Researchers in this study used mice that had the mutant AAT as a model. The study was conducted in two stages. In the first stage, they tested the effects of transplanting the bone marrow - derived cells stem cells from healthy mice into the affected mice. In the second stage, they tested the effects of transplanting human bone marrow stem cells into the affected mice. Each stage comprised of mice that received the transplanted cells (treatment group) and those that did not (control group). A subset of mice in both the groups was euthanized 1, 3 and 6 months post the treatment, to analyse how the disease had progressed.
The researchers found that both the treatment stages yielded extremely positive results. As compared to the control, there was a significant reduction in the number of liver cells containing the aggregated AAT in the treatment groups. The overall condition of the liver was found to be better, with reduced inflammation, fibrosis and cell death. They also found that an improvement in the metabolic activity of the liver leading to higher glycogen level and improved blood glucose levels.
In addition, the researchers observed that the transplanted bone marrow stem cells, both from mice and humans, developed into to healthy liver cells in the affected mice and outcompeted the diseased host liver cells. They were free from accumulated AAT, resulting in improved liver conditions.
Commenting on the importance of the results, Dr. Asok Mukhopadhyaya, the lead scientist of the study says, “Improvement in liver pathology and secretion of good AAT protein in the recipient mice suggest that bone marrow stem cell therapy has a great potential to treat both liver and lung ailments, if successfully translated to the clinic. However, pre-clinical toxicity and safety study will be the immediate next steps before clinical trial.”