Evaluation of a Novel Recombinant Human Protein Formula Compared to Donor Human Milk and Standard Formula in Neonatal Piglets

Human milk is widely considered the ideal food for infants, offering a complex blend of nutrients and protective factors that help babies grow and fight off illness. For the past six months of life, health experts recommend it as the primary diet. However, not every mother can breastfeed, and for those who cannot, infant formula serves as the necessary alternative. Most formulas today are made from cow's milk or plant-based ingredients. While these provide the basic building blocks for growth, they often lack the specific biological functions found in human milk, such as proteins that actively defend against infection or aid digestion. As food allergies become more common in young children, there is a growing need for formulas that are not only nutritious but also gentle on the immune system and closer in composition to what a mother's body naturally produces.

To address this gap, researchers developed a new type of infant formula designed to mimic the unique properties of human milk more closely than current options. This experimental formula, known as H1, replaces animal proteins with human proteins created in a laboratory. These proteins, including albumin, lactoferrin, and lysozyme, are identical to those found in human milk but are produced using recombinant technology, meaning they are grown in cells rather than extracted from animals. The goal was to create a hypoallergenic product that could support a baby's development just as well as human milk or standard formula, without triggering allergic reactions. To test whether this new approach works safely and effectively, scientists turned to a model that closely mirrors human infant physiology: the newborn piglet.

In this study, researchers raised eighteen newborn piglets in a controlled environment, delivering them via cesarean section to ensure they were born at the same developmental stage. Immediately after birth, the piglets were fitted with tubes to allow for precise feeding and monitoring. The team divided the piglets into three groups. One group received donor human milk, which served as the gold standard for comparison. A second group received a standard commercial infant formula made from cow's milk. The third group received the new experimental formula, H1. Over the course of ten days, the piglets were fed these diets, and the researchers carefully tracked their growth, blood chemistry, and the health of their internal organs. At the end of the study, the piglets were humanely euthanized so scientists could examine their tissues in detail, looking for signs of inflammation, organ development, and how well their bodies absorbed nutrients.

The results showed that the new formula performed remarkably well. The piglets fed the H1 formula grew at the same rate as those fed human milk or standard formula, gaining weight just as expected. This indicated that the new formula provided enough energy and nutrients to support healthy development. When the scientists looked at the piglets' internal organs, they found that the livers and stomachs of the H1 group were slightly smaller relative to their body size compared to the other groups. This was not a sign of poor health; rather, it suggested that the H1 formula might be easier for the stomach to process or required less metabolic work from the liver to digest. The lining of the small intestine, a critical barrier against infection, looked healthy and normal in all three groups, with no signs of damage or excessive inflammation.

Beyond physical growth, the study examined how the piglets' immune systems responded to the different foods. The researchers measured various markers in the blood and tissues that indicate inflammation or immune activity. They found no significant differences in the overall immune response between the groups, suggesting that the new formula did not cause any harmful stress or allergic reactions. In fact, the piglets fed the standard cow-milk formula showed slightly higher levels of certain white blood cells compared to historical data, hinting that the new human-based formula might be gentler on the immune system. The piglets fed H1 also had higher levels of certain amino acids, the building blocks of protein, circulating in their blood, indicating that their bodies were absorbing and utilizing the nutrients efficiently.

To ensure the new proteins in the formula actually worked as intended, the researchers tested them in the lab. They measured the activity of the recombinant human proteins to see if they could perform the same biological tasks as natural human proteins. While the lab-made versions were sometimes slightly less active than their natural counterparts, they were still fully functional. For instance, the recombinant lysozyme, which helps break down bacterial cell walls, retained about two-thirds of the activity of natural human lysozyme. The recombinant lactoferrin, which binds to iron to starve harmful bacteria, showed strong binding capabilities, even outperforming some natural bovine proteins. These tests confirmed that the proteins in the new formula were not just present, but were active and capable of providing the protective benefits associated with human milk.

The study concludes that this novel, human-protein-based formula is a safe and effective alternative for neonatal nutrition. It supports growth and organ development just as well as human milk and standard formula, while offering the potential advantage of being hypoallergenic. The findings suggest that using human-identical proteins created in a lab is a viable path forward for infant nutrition, potentially closing the gap between what babies need and what current formulas can provide. While this was a short-term study in piglets, the results provide a strong foundation for further research into how these advanced formulas might benefit human infants in the long term.