Peter Attia MD334 - Cardiovascular disease, the number one killer: development, biomarkers, apoB, and more
CHAPTERS
- 0:00 – 9:53
Defining Atherosclerotic Cardiovascular Disease
Peter Attia explains the goals of the episode: a briefer, updated version of the earlier series. Tom Dayspring defines ASCVD as cholesterol deposition in the artery wall, and the two explain why small coronary and cerebral arteries are most vulnerable and how plaque can narrow or rupture.
- •ASCVD is defined by cholesterol in the artery wall, which Dayspring calls a 'dump job'
- •Coronary and cerebral arteries are small and oxygen-sensitive, so little obstruction causes trouble
- •Plaque can gradually narrow the lumen or rupture and trigger clotting
- •Symptoms often appear only after arteries are roughly 75–80% occluded
- 9:53 – 17:19
The Decades-Long Timeline of Atherosclerosis
Attia asks what the late appearance of the disease says about its time course. Dayspring cites pediatric, military and fetal autopsy studies showing that deposition starts in childhood or earlier. They discuss sudden death as a common first presentation and the case for primordial prevention.
- •Cholesterol deposition takes decades, though it begins from childhood on
- •Autopsy studies show fatty streaks in children and subclinical disease in young soldiers
- •A large share of first MIs are fatal, and half of men with events have the first before 65
- •Fetal studies in mothers with FH show early plaque, supporting pediatric lipid testing and primordial prevention
- 17:19 – 30:54
Risk Factors vs. Risk Markers, and the Insulin Resistance Debate
Dayspring distinguishes causal risk factors from non-causal risk markers and lists age, smoking, lipid disorders and high blood pressure. They discuss why chronic kidney disease raises risk and debate whether insulin resistance is independently causal, with Attia also explaining necessary versus sufficient causes.
- •Risk factors are causal; risk markers such as calcium scores, homocysteine and inflammatory markers are not
- •Attia describes his own family history and early calcium despite average LDL
- •Chronic kidney disease brings lipid disturbances, hypertension, homocysteine, uric acid and other metabolites
- •Dayspring ties insulin resistance to its lipoprotein signatures, while Attia leans toward some independent causality
- •Attia uses smoking and lung cancer to illustrate causal but neither necessary nor sufficient
- 30:54 – 37:44
What apoB Is and How Lipoproteins Carry Cholesterol
Dayspring explains why lipids need protein carriers and introduces the apoB family. He argues that one apoB per particle makes apoB measurement a direct count of atherogenic particles and that LDL accounts for most of them.
- •Lipids travel in plasma only inside lipoproteins
- •The apoB family includes LDL, VLDL and IDL, each with one apoB per particle
- •HDL is not atherogenic and carries variable copies of apoA1
- •About 95% of apoB particles are LDLs, so apoB reflects LDL particle number
- •Cholesterol and apoB cannot be separated physiologically
- 37:44 – 48:50
How Plaque Forms: From Retention to Foam Cells
Attia and Dayspring walk through the steps once an apoB particle crosses the endothelium: binding to proteoglycans, aggregation, oxidation, macrophage uptake and foam cell formation, then a smooth muscle cap and eventual calcification. They note smoking and hypertension make the endothelium more permeable.
- •Endothelial damage and higher particle numbers raise the odds of apoB entry
- •Particles stick to proteoglycans and aggregate, and the phospholipids oxidize
- •Monocytes become macrophages that ingest particles and become foam cells
- •A smooth muscle cap forms and later calcifies, which makes calcium visible on imaging
- 48:50 – 57:50
Detecting Early Atherosclerosis and Inflammatory Markers
Attia asks whether tools exist to detect disease before calcium appears. Dayspring says advanced imaging is not ready, and discusses hs-CRP and its limits. They then describe primordial, primary and secondary prevention and why apoB is the focus.
- •CTA needs soft plaque to show disease, and newer imaging is costly and not ready for broad use
- •hs-CRP is the same assay as CRP with a different reference range, but it lacks specificity
- •Attia has seen people with low hs-CRP and nonzero calcium scores
- •Inflammatory markers are useful mainly as added worry when apoB or Lp(a) is high
- •Primordial prevention aims to act on apoB before imaging shows disease
- 57:50 – 1:03:19
Lp(a): A Highly Atherogenic Inherited Particle
Dayspring gives a short explanation of Lp(a) as an LDL carrying apolipoprotein(a), made by about 20% of people. It is far more atherogenic per particle than LDL, cannot yet be lowered directly, and he recommends testing everyone once.
- •Lp(a) is an LDL particle with apo(a) attached to its apoB
- •Particle for particle it is seven to eight times more atherogenic than LDL
- •About 20% of people inherit it, so billions are affected
- •Everyone should be tested once, and the current response is controlling other risk factors
- 1:03:19 – 1:09:20
Why apoB Rises with Age and How Diet Affects It
Attia notes that children have low apoB and asks why levels rise with age. Dayspring attributes it mainly to reduced hepatic clearance through LDL receptor expression. They discuss how saturated fat and triglycerides can be dietary levers for a hypothetical patient with apoB of 100.
- •Rising apoB is mostly due to reduced liver clearance, not overproduction
- •LDL receptor expression is regulated by nuclear transcription factors responding to lifestyle
- •Saturated fat can suppress LDL receptor expression and raise apoB
- •Attia names lowering triglycerides and saturated fat as the two best nutritional levers
- 1:09:20 – 1:25:58
Triglycerides, Insulin Resistance, and the Rise of apoB
Dayspring explains how insulin resistance drives large VLDLs, apoC3 and CETP-mediated exchange that yields small, triglyceride-rich LDL poorly cleared by the liver. This raises apoB even when LDL cholesterol looks unchanged, and he argues triglycerides above about 100 deserve attention and that apoB is the treatment goal.
- •Insulin resistance makes the liver overproduce triglycerides in large VLDLs carrying apoC3
- •CETP exchanges triglyceride for cholesterol, lowering HDL cholesterol and making small LDL
- •Small LDL is poorly recognized by the LDL receptor, so apoB rises and LDL cholesterol and apoB become discordant
- •The 150 triglyceride cutoff is criticized, and concern begins near 100
- •Fibrates lowered triglycerides without reducing MACE, so apoB is the goal
- 1:25:58 – 1:33:25
LDL Particle Size, Remnants, and Non-HDL Cholesterol
Attia asks whether LDL size matters if apoB is known. Dayspring says apoB captures the risk and that big 'fluffy' LDL is not protective, then explains remnant particles. The two describe how apoB can hide differences in Lp(a) and remnants, and Dayspring suggests non-HDL cholesterol as a practical check.
- •Large LDL is also poorly cleared, as seen in FH
- •Remnant particles carry five to seven times more cholesterol than LDL and are inflammatory
- •Equal apoB can hide very different Lp(a) and remnant contributions
- •Non-HDL cholesterol (total minus HDL) can hint at remnants when apoB looks good
- 1:33:25 – 1:41:57
Why HDL Cholesterol Is a Poor Marker of Heart Health
Attia asks about HDL and its confusing reputation. Dayspring explains that HDL function depends on its proteins and phospholipids rather than its cholesterol content, so HDL-C cannot show protection. Attia shares a case of a friend with very high HDL-C who had a high calcium score.
- •HDL function is unrelated to HDL cholesterol level
- •HDL carries over 150 proteins and a phospholipid coat that determine function
- •Low HDL-C usually signals high triglycerides and high apoB
- •High HDL-C is not cardiac immortality, and Dayspring checks apoB in everyone
- •Attia's friend with high HDL-C and low LDL-C had significant calcium
- 1:41:57 – 1:51:39
Cholesterol in the Brain: Synthesis and Lipoproteins
Attia shifts to the brain and asks about cholesterol pools and movement across barriers. Dayspring explains the brain makes all its own cholesterol, which turns over very slowly, and describes how astrocytes supply neurons through apoE-based brain lipoproteins.
- •The brain holds the most cholesterol of any organ and no peripheral lipoprotein crosses into it
- •Brain cholesterol has a half-life of about five years versus two to three days in plasma
- •Oligodendrocytes make cholesterol for myelin, and astrocytes supply neurons in adulthood
- •Brain lipoproteins use apoE, and small apoA1 can cross the blood-brain barrier
- 1:51:39 – 1:55:59
ApoE Genotype and Alzheimer's Risk
Dayspring links ApoE4 to dysfunctional brain HDL. Attia interjects to clarify the three isoforms, the combinations that include E4, and that the effect is a susceptibility rather than a deterministic one. They note that a single amino acid change alters the protein's shape and function.
- •ApoE4 brain lipoproteins are dysfunctional and less able to move cholesterol and clear amyloid and tau
- •There are three isoforms and six combinations, three of which include E4
- •Risk rises from two-four to three-four to four-four, but E4 is not deterministic
- •A single amino acid difference changes protein shape and function
- 1:55:59 – 2:08:29
Brain Cholesterol Biomarkers: 24S-Hydroxycholesterol and Desmosterol
Dayspring describes how neurons convert excess cholesterol to 24S-hydroxycholesterol, which can leave the brain. He explains that astrocytes use the desmosterol pathway, making serum desmosterol a possible marker of brain cholesterol synthesis, while peripheral cells mostly use the lathosterol pathway.
- •Neurons make 24S-hydroxycholesterol, a water-soluble oxysterol that crosses the blood-brain barrier
- •Serum 24S-hydroxycholesterol may reflect brain cholesterol clearance
- •Astrocytes mainly use the desmosterol pathway, and serum desmosterol correlates with CSF desmosterol
- •Low serum desmosterol was associated with more cognitive impairment and Alzheimer's
- •Lathosterol mostly reflects peripheral synthesis
- 2:08:29 – 2:16:20
Statins, the Brain, and Alternative Lipid-Lowering Options
Dayspring speculates that brain fog from statins might involve sensitivity reflected in desmosterol, and says all statins ultimately reach the brain. Both note no trial signal that statins worsen dementia, and discuss starting with low-dose statins combined with ezetimibe, bempedoic acid or PCSK9 inhibitors.
- •Brain fog is rare, and Dayspring hypothesizes desmosterol could help identify sensitive people
- •Hydrophilic versus lipophilic statins make little difference, since all reach the brain
- •Attia notes secondary-outcome trials show neutral or favorable dementia effects, though no trial had dementia as primary outcome
- •Other apoB-lowering drugs do not get into the brain, so there is rarely need for high-dose statins
- •Low-dose statin plus other agents can lower apoB with few side effects
- 2:16:20 – 2:24:01
Looking Ahead: Therapeutics, Diagnostics, and NLA Statements
Attia asks what Dayspring is most excited about in the next three to five years. Dayspring describes coming drugs, possible HDL functionality tests, imaging and sterol biomarkers, and the NLA's recent statements on apoB and Lp(a). He notes that guidelines won't yet replace the lipid profile with apoB and that Lp(a) drug outcomes are pending.
- •ApoB can mostly be brought to goal now, with new and oral PCSK9 agents and drugs for rare disorders coming
- •Dayspring hopes for HDL functionality tests and wider availability of sterol biomarkers
- •Inflammatory markers are not the therapy goal; apoB is
- •The NLA published statements on apoB and Lp(a)
- •Whether Lowering Lp(a) reduces MACE will start to be answered by a readout next year
