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Researchers are testing the potential of an orally delivered, plant-based insulin formulation in the treatment of diabetes. Image credit: HUIZENG HU/Getty Images.
  • Recent research has highlighted the potential risks of rapid insulin absorption from insulin pens, possibly leading to hypoglycemia, while automated pumps remain costly and inaccessible.
  • Now, researchers from the University of Pennsylvania’s School of Dental Medicine propose a potential solution with a plant-based oral delivery of insulin.
  • The plant-based alternative contains all three essential peptides, shields insulin through plant cell walls, and regulates blood sugar levels similar to natural insulin, reducing hypoglycemia risk.
  • This innovation could revolutionize diabetes treatment, providing affordable and effective medication with global accessibility.

The current methods of insulin delivery present some risk for patients with diabetes, despite their life-saving role.

It is known that the administration of insulin through insulin pens can lead to the rapid absorption of insulin into the bloodstream, potentially causing hypoglycemia — lower-than-optimal blood sugar levels.

Although automated insulin pumps offer a solution by providing accurate insulin delivery and reducing this risk, they are costly and accessible to only a fraction of diabetes patients worldwide.

However, new research, published in the journal Biomaterials, suggests that a plant-based oral delivery method of proinsulin could address these limitations.

Despite the long-term use of clinical insulin, it lacks one of the three peptides found in natural insulin.

To address this issue, the researchers developed a plant-based insulin that includes all three peptides and can be taken orally.

The robustness of plant cell walls shields insulin from stomach acids and enzymes until it is broken down by gut microbes. Subsequently, the released insulin is transported to the liver through the gut-liver axis.

In this new research, conducted in mouse models of diabetes, the research team observed that their plant-based insulin effectively regulated blood sugar levels within 15 minutes of ingestion, exhibiting a similar performance to naturally secreted insulin.

In contrast, mice treated with traditional insulin injections experienced a rapid decline in blood glucose levels, which resulted in temporary hypoglycemia.

One of the major drawbacks of the existing delivery system is the significant risk of hypoglycemia, which can potentially lead to a coma.

However, this novel orally-administered insulin contains all three proteins and is directly delivered to the liver. It functions similarly to natural insulin, thereby reducing the likelihood of hypoglycemia.

The researchers had been extensively studying the applications of plant-derived proteins for quite some time. In a previous study, they demonstrated the commercial feasibility of producing a cost-effective medication using lettuce plants.

To create plant-based insulin, they first identified the human insulin genes and utilized a method known as a “gene gun” to forcefully introduce the genes through the resilient cell walls of plants.

These insulin genes were then incorporated into the genome of the chosen plant, in this case, lettuce.

The resulting seeds permanently inherited the insulin genes, and the mature lettuce plants were freeze-dried, ground, and prepared for oral administration in accordance with the regulatory guidelines set by the Food and Drug Administration (FDA).

This production process is considerably different from the traditional method of insulin production, which involves cultivating the hormone within bacteria or yeast cells.

The conventional approach is costly and necessitates purification as well as a low temperature for transportation and storage.

Conversely, the plant-based insulin production method eliminates the need for expensive laboratory equipment.

In addition, the resulting product remains stable at room temperature, eliminating the need for costly cold storage throughout the post-production process.

With the new production method, such post-production costs are eliminated, as the plant-based insulin is shelf-stable.

Moving forward, the researchers intend to conduct trials using plant-based insulin on both dogs and humans.

Dogs, in particular, often suffer from diabetes, and their owners must be present to administer insulin three times a day.

The research team has previously conducted studies on dogs with conditions like hemophilia or heart disease, allowing them to develop expertise in mixing the plant powder with their food and even adding bacon flavor.

In the case of humans, utilizing plant-based delivery methods for medications has the potential to revolutionize the treatment of diabetes and various other diseases.

This innovative delivery system has the potential to transform not only insulin treatment but also the entire treatment approach for other medications.

The research is not without precedent, as the FDA has already approved drugs made in plant cells for oral delivery, for example, Palforzia — using peanut plant cells to treat allergies.

The researchers emphasize the importance of affordability and global access to healthcare, which serve as the underlying principles driving their research.

By making insulin more affordable and simultaneously enhancing its quality, patients can receive improved medication at a reduced cost.

Dr. Henry Daniell, vice-chair and W.D. Miller professor in the Department of Basic & Translational Sciences, the University of Pennsylvania’s School of Dental Medicine, and lead researcher of the study, highlighted the key findings to Medical News Today.

He emphasized the issues around insulin accessibility, noting that “around the globe, one-third of the population earn $2 per day, and insulin is beyond their reach.”

In addition, Dr. Daniell noted how this research “addresses the high cost of insulin,” pointing to previous studies about the high cost of insulin and how patients ration insulin due to the cost, risking their health and well-being.

“This study addresses the risk in current insulin delivery methods. Except [for] a very small population that can afford sophisticated pumps to inject [the] correct insulin dose by measuring glucose concentration, the rest of the diabetic population (>90%) use insulin pens. All of them are at risk of low sugar levels — two large clinical studies performed at Ivy League institutions are cited in our article. Oral delivery pretty much eliminates hypoglycemia (low sugar levels).”

– Dr. Henry Daniell

Daniell also pointed out that “oral delivery is noninvasive delivery and insulin in plant cells can be stored at ambient temperature for many years.”

Kristen Carli, a registered dietitian nutritionist, not involved in this research said that “this is great news for those suffering from diabetes.”

“Not only is this synthetic pro-insulin going to save patients money, it will also offer more realistic management of blood sugars, helping to avoid the risk of hypoglycemia,” Carli explained.

“As more and more individuals get diagnosed with diabetes, having a reliable source of insulin that is affordable and more effective than current insulin offerings is great news! I’m thrilled to see science and technology working to create affordable solutions for patients. I hope the price of this offering remains affordable.”

– Kristen Carli