CD38

Speaker 1...So, let’s talk about CD38, a molecule that’s been getting a lot of attention in the longevity space. What exactly is it?

Speaker 2CD38 is an enzyme, and a pretty significant one when we're discussing cellular aging. Its primary role, relevant to longevity, is that it's a major consumer of NAD+.

Speaker 1NAD+, the coenzyme vital for cellular energy and repair, right?

Speaker 2Exactly. Our NAD+ levels naturally decline as we age, and CD38 is a big part of that story. Research, like a study in *Nature Metabolism* in 2020, has shown that CD38 activity actually rises with age. This increased activity drains our NAD+ pool, which isn't ideal for healthy aging.

Speaker 1So, if CD38 is consuming NAD+, then inhibiting CD38 could be a strategy to preserve NAD+ levels?

Speaker 2That's the hypothesis. And there's some interesting work around compounds that act as CD38 inhibitors. Apigenin, a flavonoid found in many plants, is one that’s been identified to inhibit CD38, thereby slowing NAD+ breakdown.

Speaker 1That sounds promising, but what's still unknown or unproven here?

Speaker 2Well, while the lab and animal data are compelling regarding CD38’s role and the impact of inhibitors like apigenin on NAD+ levels, the direct, long-term impact on human longevity and disease prevention is still being actively researched. We understand the mechanism, but translating that into definitive human outcomes takes time and more robust clinical trials. It's an area of intense study, but not yet a proven intervention for human healthy lifespan extension.

Speaker 1...and this is key, because CD38 is a major NAD⁺-consuming enzyme. As we age, its activity rises, effectively draining our NAD⁺ reserves.

Speaker 2Right. So, the theory is, if you can inhibit CD38, you could slow that NAD⁺ breakdown and help preserve those vital levels. And this is where apigenin comes into the conversation.

Speaker 1Exactly. Pre-clinical work, like the study in Nature Metabolism from 2020, showed apigenin can indeed inhibit CD38. It’s a promising mechanism.

Speaker 2Promising, yes, but that’s often the point where the hype can outpace the human evidence. What do the actual clinical trials in humans show about apigenin's effect on NAD⁺ or even longevity markers?

Speaker 1That's a crucial distinction. While the *mechanism* in a petri dish or in animal models suggests a pathway, direct human evidence for apigenin raising NAD⁺ levels or translating into human longevity benefits is still largely unproven. We simply don't have large-scale, placebo-controlled human trials demonstrating that yet.

Speaker 2So, for all the excitement around apigenin’s ability to inhibit CD38, we still don’t know if that translates into a measurable, beneficial increase in NAD⁺ in people, or if it impacts health in the way we hope.

Speaker 1Precisely. The *in vitro* and animal data are compelling for the mechanism, but the human evidence for clinical outcomes, or even just NAD⁺ levels, remains to be established. It’s an active area of research, but for now, it's more about potential than proven results in humans.

Speaker 1...and this is really interesting when we talk about NAD⁺. We know NAD⁺ levels decline with age, and that's linked to a host of age-related issues. But *why* do they decline?

Speaker 2Exactly. One major player in that decline seems to be an enzyme called CD38. Research, like a study in *Nature Metabolism* in 2020, indicates that CD38 activity rises significantly as we get older.

Speaker 1And what does CD38 do? It’s a huge consumer of NAD⁺. So, as CD38 activity ramps up, it’s essentially draining the NAD⁺ pool faster than the body can replenish it. It's like having a leak in your bucket that gets bigger over time.

Speaker 2Right. Now, there’s a lot of buzz around compounds that might inhibit CD38. Apigenin, for example, is one that’s been identified. The idea is that by slowing CD38’s breakdown of NAD⁺, you could help preserve those crucial NAD⁺ levels.

Speaker 1That’s the theory, and it's compelling. But what’s still genuinely unknown? While we see this relationship in cells and animal models, the direct, long-term impact of CD38 inhibition on human longevity and healthspan, using something like apigenin, is still being actively researched.

Speaker 2Yes, exactly. We know apigenin inhibits CD38, and CD38 consumes NAD⁺. But definitively proving that apigenin *directly* translates to improved human healthy aging outcomes by this specific mechanism, in large-scale human trials, is still an open question. We're connecting the dots, but some of those dots are bigger than others.