Researchers discovered that a specific type of heart surgery called Glenn surgery can cause dangerous blood vessel problems in the lungs. Using advanced genetic testing on rat lungs, they found that vitamin A plays an important role in preventing these complications. When rats didn’t get enough vitamin A, their blood vessel problems got worse. When they received extra vitamin A, the problems improved. This discovery suggests that vitamin A might be a simple, natural way to help patients who have had this type of heart surgery avoid serious lung complications.

The Quick Take

  • What they studied: Whether vitamin A affects dangerous blood vessel problems that develop in the lungs after a specific type of heart surgery in rats
  • Who participated: 16 adult rats total: 8 rats had the Glenn surgery and 8 had a fake surgery for comparison. Researchers then tested different vitamin A levels in their diets
  • Key finding: Rats that didn’t get enough vitamin A developed worse blood vessel problems (p<0.01, meaning this result was very unlikely to happen by chance). Rats that got extra vitamin A had fewer problems
  • What it means for you: This early research suggests vitamin A might help prevent serious lung complications in children who have Glenn heart surgery, but much more research in humans is needed before doctors could recommend this as a treatment

The Research Details

Scientists used a rat model to study what happens in the lungs after Glenn surgery. They performed advanced genetic testing called single-cell RNA sequencing, which is like reading the instruction manual for each individual cell to see which genes are turned on or off. They compared lungs from rats that had Glenn surgery to rats that had a fake surgery (control group). They also compared their findings to existing research on a human genetic disease called hereditary hemorrhagic telangiectasia that causes similar blood vessel problems. Finally, they tested whether changing vitamin A levels in the rats’ diet would affect the blood vessel problems that developed.

This research approach is important because it helps scientists understand the exact biological mechanisms causing these dangerous blood vessel complications. By identifying that vitamin A signaling is reduced after surgery, researchers can potentially develop simple dietary interventions rather than complicated medications. The comparison to a human genetic disease helps confirm that the findings might be relevant to real patients

This is early-stage research published as a preprint, meaning it hasn’t been reviewed by other scientists yet. The sample size is small (8 rats per group), so results need confirmation in larger studies. The research was conducted in rats, not humans, so findings may not directly apply to people. However, the use of advanced genetic technology and comparison to human disease models strengthens the findings

What the Results Show

Researchers identified that Glenn surgery causes significant changes in lung blood vessel cells. About 17% of genes in these cells showed different activity levels compared to the control group. Importantly, genes controlled by vitamin A (specifically a form called retinoic acid) were less active after surgery. When researchers reduced vitamin A in the rats’ diet, the dangerous blood vessel problems got significantly worse. When they increased vitamin A in the diet, the problems improved. This suggests vitamin A is protective against these complications.

The study found that the gene expression patterns in the rat lungs after Glenn surgery were similar to patterns seen in a human genetic disease called hereditary hemorrhagic telangiectasia. About 18% of the changed genes overlapped between the two conditions. The researchers also identified that vitamin A affects other cellular signaling pathways involved in cell growth and survival, suggesting multiple protective mechanisms

This is the first study to use advanced single-cell genetic analysis to understand Glenn surgery complications in detail. Previous research knew these blood vessel problems were common but didn’t understand why. The connection to vitamin A signaling is novel and suggests a new direction for treatment. The similarity to hereditary hemorrhagic telangiectasia suggests findings might eventually help patients with both conditions

This research was conducted in rats, not humans, so results may not directly translate to people. The sample size was small (8 rats per group), which limits confidence in the findings. The study was published as a preprint, meaning it hasn’t been peer-reviewed by other scientists yet. The researchers didn’t test whether vitamin A supplements would work in actual patients, only in rats. Long-term effects of vitamin A supplementation weren’t studied

The Bottom Line

This research is too early to recommend vitamin A supplements for patients who have had Glenn surgery. It suggests vitamin A may be helpful (moderate confidence level), but human studies are needed first. Patients should not change their vitamin A intake based on this study alone without talking to their doctor

This research is most relevant to children who have had or will have Glenn heart surgery and their families. It may eventually be relevant to people with hereditary hemorrhagic telangiectasia. It should NOT be used as a reason for healthy people to change their vitamin A intake. People with liver disease or those taking certain medications should be especially cautious about vitamin A supplementation

This is very early research. It will likely take 3-5 years of additional studies before doctors could consider recommending vitamin A for Glenn surgery patients. Human clinical trials would need to happen before any treatment recommendations could be made

Want to Apply This Research?

  • For patients who have had Glenn surgery: track daily vitamin A intake (in micrograms) and any breathing symptoms or exercise tolerance changes weekly. Note any medical appointments or imaging results related to lung complications
  • Users could log their current vitamin A intake from food sources (carrots, sweet potatoes, spinach, liver) to establish a baseline. Once research progresses, the app could help track whether recommended vitamin A levels are being met through diet alone or if supplementation is needed
  • Long-term tracking should include: monthly notes on breathing or exercise tolerance, quarterly vitamin A intake summaries, and documentation of any medical imaging or test results related to lung function. This creates a personal health record to share with doctors as research develops

This research is preliminary and has not been peer-reviewed. It was conducted in rats and does not yet apply to human treatment. Do not change vitamin A intake or supplement use based on this study without consulting your cardiologist or primary care physician. Vitamin A supplements can be harmful in high doses and may interact with medications. This information is for educational purposes only and should not replace professional medical advice. Parents of children with single ventricle heart disease should discuss any dietary changes with their child’s medical team.