In the world of diabetes management, semaglutide – recognized by its brand names Ozempic, Wegovy, and Rybelsus – has been creating ripples with its dual potential: controlling blood sugar and promoting weight loss. But wait, the scene-stealer might be just around the corner. The U.S. Food and Drug Administration (FDA) has its eyes on Eli Lilly's tirzepatide, also known as Mounjaro, for its weight loss capabilities.
Mounjaro's Claim to Fame
While already endorsed for Type 2 diabetes management, studies presented to the FDA by Eli Lilly indicate Mounjaro's potential to decrease body mass by up to 15% at peak dosage. A breakthrough aspect? While semaglutide focuses on the glucagon-like peptide-1 (GLP-1) molecule crucial for insulin secretion, tirzepatide is groundbreaking as it targets both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP).
Unpacking the Mounjaro Mystery
A freshly published study in Nature Metabolism delves deeper. Partnering with experts from Eli Lilly and Novo Nordisk (the creators of Ozempic and Wegovy), researchers set out to uncover how tirzepatide wields its twin powers over blood sugar and weight. Their laboratory involved both mice and human insulin-producing cell samples.
Jonathan Campbell, the senior author, and associate professor of medicine at Duke University, emphasizes, "Historically, GIP has been seen as the underdog compared to GLP-1.” While GLP-1's prowess lies in stimulating insulin production and suppressing hunger, GIP, though similar, generally lagged in strength.
The Unforeseen GIP Response
Scientists had postulated that tirzepatide's primary mechanism was via activating GLP-1 receptors. However, their research painted a different picture. Campbell reveals, "GIP was indispensable.” In experiments using human pancreatic cells, blocking GIP nullified tirzepatide's impact on insulin secretion. This revelation was contrary to their initial hypothesis.
The underlying reason? A discrepancy between mice and human cells. The GIP receptor genetic sequences differ between these species, making mouse models slightly misleading for human-based research.
Future Implication
This discovery paves the path for queries regarding the efficacy of combining GLP-1-based drugs with GIP-centric medicines for diabetes and weight management. More extensive research can unravel whether multi-target strategies might be more potent. Campbell highlights the potential, "This could provide physicians with a more diversified arsenal to treat patients.”
Concluding on a hopeful note, Campbell aims to deepen this study by examining GLP-1 and GIP across a broader spectrum of human cell samples. By incorporating cells from individuals with diabetes, it could illuminate optimal strategies to manage blood sugar and weight effectively.
