#407 ‒ Preventing cardiovascular and Alzheimer's disease: lowering LDL early, APOE4, and promising new therapies | Michael Davidson, M.D.
Cardiologist Michael Davidson discusses the history and future of CETP inhibitors, focusing on Obicetrapib's potential to significantly lower LDL, ApoB, and Lp(a) for cardiovascular prevention. He also explores its promising role in Alzheimer's disease prevention, particularly for APOE4 carriers, and challenges in drug development.
Deep Dive Analysis
20 Topic Outline
Michael Davidson's Path to Lipidology and Prevention
Rethinking Primary Prevention of ASCVD
Causality of LDL and Challenges in Treatment
History of CETP Inhibitors and Early Failures
Mechanisms of HDL Function and Reverse Cholesterol Transport
Lessons from Dalcetrapib and Evacetrapib Trials
Merck's Anacetrapib Trial and LDL Lowering Proof
Reviving Obicetrapib: Potency and Initial Trials
Discordance of Lipid Biomarkers with CETP Inhibition
Obicetrapib's Lp(a) Lowering Effect
Future Role of Obicetrapib in Cardiovascular Prevention
Obicetrapib's Potential in Alzheimer's Disease Prevention
Brain Cholesterol Metabolism and APOE4 Mechanism
Biomarker Evidence for Obicetrapib in Alzheimer's
Challenges and Future Directions for Alzheimer's Prevention
Role of Omega-3 Fatty Acids (EPA and DHA) in Health
AI in Clinical Trials and Drug Development Challenges
Statins and Diabetes Risk
Biotech Investment Landscape and Klotho Program Update
Closing Advice for APOE4 Carriers
8 Key Concepts
Primordial Prevention
Stopping plaque from forming in arteries before it even exists, rather than waiting for significant plaque buildup or events like heart attack or stroke. This approach aims to prevent disease from ever starting.
Cholesterol Ester Transfer Protein (CETP)
A protein that transfers cholesterol from HDL to LDL. Inhibiting CETP leads to increased HDL and decreased LDL, and also improves LDL clearance from the liver.
Reverse Cholesterol Transport
The process by which HDL picks up excess cholesterol from peripheral tissues, including artery walls, and transports it back to the liver for clearance and excretion. This was initially thought to be the primary mechanism by which high HDL was protective.
Mendelian Randomization
A research method that uses genetic variants as natural experiments to assess the causal effect of a modifiable risk factor on a disease outcome. It has confirmed that LDL lowering, regardless of the mechanism, causally reduces cardiovascular risk.
APOE4 Genotype
A genetic variant of the apolipoprotein E gene associated with a significantly increased risk of Alzheimer's disease, especially in homozygotes. It is linked to impaired cholesterol efflux and lipidation in the brain, leading to toxic cholesterol buildup.
Blood-Brain Barrier
A highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from non-selectively crossing into the extracellular fluid of the central nervous system. It largely separates brain lipid metabolism from systemic lipid metabolism.
P-tau 217 (Phosphorylated Tau 217)
A specific phosphorylated form of the tau protein that is an early and highly predictive biomarker for the presence of amyloid plaques and the progression of Alzheimer's disease. It appears earlier than P-tau 181 and correlates well with amyloid PET scans.
Lyso-PC-DHA (Lysophosphatidylcholine-DHA)
A specific form of DHA (docosahexaenoic acid) that is the preferred substrate for the MFSDA2 transporter, allowing it to efficiently cross the blood-brain barrier and deliver DHA to the brain.
9 Questions Answered
LDL management faces resistance because many people believe it can be entirely controlled by lifestyle, and there's a perception of it being a 'pharma conspiracy,' despite strong genetic factors influencing LDL levels.
Early CETP inhibitors like torcetrapib failed due to off-target effects, such as increasing blood pressure and steroid production, which led to increased mortality, rather than issues with the CETP target itself.
No, high HDL cholesterol is not always protective. While epidemiologically associated with lower risk, some genetic factors (like SRB1 mutation) or lifestyle choices (like alcohol consumption) can raise HDL but either do not protect or even increase risk.
Clinical trials and observational data do not show that statins cause Alzheimer's disease. While statins may not directly prevent Alzheimer's pathology in the brain due to the blood-brain barrier, they can reduce vascular dementia risk.
The exact mechanism is unknown, but the increased risk of type 2 diabetes with statins is dose-related, age-related, and weight-related, being more common in older, obese patients on high-dose statins.
The brain has its own distinct cholesterol metabolism, largely separated by the blood-brain barrier. There is no LDL in the brain; instead, lipoproteins in the brain are HDL-like particles containing APOE.
Alzheimer's pathology begins decades before clinical symptoms like MCI appear. By the time dementia is diagnosed, the brain has already undergone significant neurodegeneration, making intervention at this stage largely ineffective.
P-tau 217 is an early and highly predictive biomarker for Alzheimer's disease, correlating strongly with amyloid plaques on PET scans and predicting disease progression. It offers a less invasive and potentially more accurate way to detect early pathology.
Standard DHA supplements have limited ability to cross the blood-brain barrier. DHA needs to be in a specific lyso-PC (lysophosphatidylcholine) form to be efficiently transported into the brain via the MFSDA2 transporter.
9 Actionable Insights
1. Prioritize Primordial Prevention
Start preventing plaque formation in arteries early in life, ideally before plaque exists, as it’s significantly easier to stop plaque from forming than to reverse it once it’s established.
2. Target Lifetime LDL Below 80
Aim to maintain LDL cholesterol below 80 mg/dL throughout your lifetime, as data suggests this level can prevent heart disease, following the ‘8-gram rule’ of lifetime cholesterol exposure.
3. Treat Causal Disease Drivers Early
Focus prevention efforts on causal drivers of disease like elevated LDL, similar to how smoking or high blood pressure are treated, regardless of short-term risk metrics, to achieve long-term health benefits.
4. Consider Earlier Statin Intervention
Advocate for earlier statin use, especially in the 20-40 age range, to effectively prevent plaque formation, noting that this critical timeframe is when plaque begins to form rapidly.
5. Avoid High-Dose Statins
Opt for lower-dose statins combined with other lipid-lowering therapies instead of high-dose statins (e.g., 80mg atorvastatin, 40mg rosuvastatin) due to diminishing returns on LDL lowering and increased risk of side effects like elevated transaminases and diabetes.
6. Manage High Lp(a) with LDL Lowering
If you have high Lp(a), prioritize aggressively lowering LDL cholesterol, as this substantially mitigates overall cardiovascular risk, even if specific Lp(a)-lowering therapies are not yet widely available.
7. Address APOE4 with Lifestyle
For individuals with the APOE4 genotype, focus on aggressive lifestyle modifications including exercise, maintaining normal blood pressure, avoiding smoking, and managing lipids to mitigate Alzheimer’s risk.
8. Evaluate High HDL Carefully
Do not assume high HDL cholesterol is always protective; some genetic factors (e.g., SRB1 mutation) or lifestyle choices (e.g., alcohol) can raise HDL while increasing or not protecting against cardiovascular risk.
9. Utilize Advanced Risk Assessment
For younger individuals with family history or other concerns, consider genetic testing, polygenic risk scores, coronary calcium scanning, or advanced plaque analysis to gain more information about higher ASCVD risk.
7 Key Quotes
It's a lot easier to stop it from forming than it is to reversing it when it already exists.
Michael Davidson
The data says that if you keep your LDL below 80 throughout your lifetime, you don't get heart disease.
Michael Davidson
It is that smoking is causally related to cancer. And therefore, the time to quit smoking is before you start. And if you've already started, the time to quit smoking is today, regardless of your risk going forward.
Peter Attia
I've always been, it's LDL, it's LDL. Now, I think the argument is stronger that there's nothing special about statins other than they're very effective and well-tolerated.
Michael Davidson
Alzheimer's is not a disease of old age. It's a disease of middle age that presents in old age.
Peter Attia
The net benefit is still so great. Unfortunately, it's a big discussion with patients very frequently. I don't want diabetes. Why are you giving me this? Your explanation is what we try to talk to them about. It's the overall net benefit is still very much in favor of taking the statin.
Michael Davidson
It's all about hope because it's such a devastating disease.
Michael Davidson