The Role of NMN in Mitigating Dry Eye Disease: Aiding Cell Survival and Reducing Inflammation

Dry eye disease, one of the most common eye disorders, presents significant discomfort to patients. The disease is primarily characterized by inflammation and elevated salt concentrations in tears, also known as hyperosmolarity, leading to loss of cell moisture. This can inflict injuries on the eye surface and potentially impair vision.

Current treatment approaches, such as eye drops mimicking natural tears, primarily address symptoms, leaving a gap in preserving eye cell functionality post hyperosmolarity damage. Previous research has suggested that nicotinamide mononucleotide (NMN) could play a role in cell protection in conditions like retinal detachment, raising the question of its potential use in dry eye disease.

The Protective Effects of NMN: A Study

In a study published in the Journal of Inflammation Research in 2021, a team of researchers, led by Zhu from Changshu Number 2 People’s Hospital in China, explored the impact of NMN on eye cells from mice subjected to salt-induced hyperosmolarity.

Their findings highlighted that NMN treatment managed to uphold cell viability, reducing inflammation by triggering Sirtuin1 (SIRT1), a protein integral to metabolism and DNA integrity.

Moreover, NMN was found to guide immune cells in transitioning from destructive to healing states. Should these findings hold true for humans, NMN could pave the way to prevent dry eye disease-related injuries.

How NMN Helps in Dry Eye Disease

NMN boosts a molecule called NAD+, which plays a big role in our cells' energy and health. This molecule is also used by a protein named SIRT1, which helps maintain our DNA and metabolism. By increasing NAD+, NMN can help protect our eyes from injuries like those seen in retinal detachment. So, it's important to study how NMN can help with dry eye issues.

NMN Strengthens Eye Cells in Dry Eye Situations

When the research team exposed mouse eye cells to high salt levels, a situation similar to dry eyes, they found that NMN could save these cells from dying.

NMN Teams Up with SIRT1 to Protect Eyes

NMN can reduce inflammation in our eyes. The researchers noticed that it reduces IL-17a, which causes inflammation. They also found that NMN boosts levels of the protein SIRT1. If SIRT1 is blocked, inflammation gets worse. This means NMN helps fight inflammation by working with SIRT1, especially in high salt conditions.

NMN Helps Immune Cells Heal

The scientists studied NMN more closely and found it helps certain immune cells called macrophages. Some of these cells can cause harm while others can help heal. When there's too much salt, more of the harmful cells show up. But with NMN, more of the helpful healing cells come forward. This means NMN can make these cells act in a helpful way instead of a harmful one.

Future Implications: NMN and Human Dry Eye Disease

Future research in human cells will ascertain if NMN could be used as a therapeutic agent to protect against hyperosmolarity in dry eye disease. If confirmed, a combination of NMN treatment and artificial tear eye drops could slow down the progression of this widespread eye condition.

Conclusion

This study advances our understanding of the role of NMN in dry eye disease, particularly in promoting cell survival and reducing inflammation. NMN's capacity to activate SIRT1 and guide the transition of macrophages from a destructive to a healing state could have significant implications for treating this common eye ailment. Further research into the effects of NMN on human cells is warranted to fully appreciate its potential in managing dry eye disease.

References

Meng YF, Pu Q, Dai SY, Ma Q, Li X, Zhu W. Nicotinamide Mononucleotide Alleviates Hyperosmolarity-Induced IL-17a Secretion and Macrophage Activation in Corneal Epithelial Cells/Macrophage Co-Culture System. J Inflamm Res. 2021 Feb 22;14:479-493. doi: 10.2147/JIR.S292764. PMID: 33658825; PMCID: PMC7917392.