New study indicates that a decrease in nerve cell cholesterol caused by cortisol, inflammation & low SIRT1 activity may be a cause of major depression.
So, do statins exacerbate depression?
And since SIRT1 is NAD⁺-dependent, could NAD⁺ boosters treat or prevent depression? …🧵
Around 5–5.7% of adults worldwide experience depressive disorders at any given time. >280 million people!
Lifetime depression diagnoses in the U.S. have risen. ~29% report ever being diagnosed, up from ~20% a decade ago
Using human stem cell–derived prefrontal cortex neurons, the authors modeled 3 major risk factors: chronic cortisol (stress), interferon-α (inflammation), and loss of SIRT1, a longevity-linked NAD⁺-dependent deacetylase
Strikingly, all three caused the same phenotype: dendritic atrophy, synapse loss, reduced glutamate signaling, and neuronal hypoactivity
SIRT1 loss alters expression of cholesterol synthesis & transport, reducing membrane cholesterol and impairing synaptic function. This links metabolism, epigenetics, and mood
Lowering cholesterol in healthy neurons reproduced depression-like defects. Conversely, restoring cholesterol rescued synapses and glutamate responses across all models
This study raises a testable idea: could NAD⁺ precursors (NR, NMN, etc.) help restore SIRT1 activity, normalize neuronal cholesterol, and improve synaptic function in subsets of major depressive disorder?
NMN has been reported to improve depression-like behaviors in stress/corticosterone models in mice. Translation to humans is not known
There are mouse studies suggesting another NAD precursor NR can reduce depression-like behaviors in specific contexts
In my experience, NMN has improved my mood over the past 15 years - and clinical trials should be initiated to test it
As to whether statins are a risk: possibly. Brain cholesterol is largely synthesized locally (by neurons and especially astrocytes). Peripheral cholesterol does not cross the blood–brain barrier in meaningful amounts
Lipophilic statins (e.g., simvastatin, lovastatin, atorvastatin/Lipitor) can cross the blood brain barrier. Hydrophilic statins (e.g., pravastatin, rosuvastatin/Crestor) cross poorly
Some studies show statins associating with depressive symptoms while others show no effect or even benefit (likely via anti-inflammatory or vascular effects)
A subset of individuals may be vulnerable to cholesterol-lowering drugs, especially if brain cholesterol or SIRT1/NAD⁺ are already altered by genetics, age, or disease
Good news: Another study showing that fasting can help cancer patients. A 16 hour fast enhanced the cancer-killing activity of T cells and synergized with immunotherapy to reduce tumor size, ostensibly by causing cancer cells to release the amino isoleucine... 🧵
In the tumor microenvironment (TME), there was increased isoleucine processing and intracellular acetyl-coA, along with increase expression of genes involved in the starvation response, autophagy
There were also alterations in glutamine metabolism, a known source of energy for cancer cells
Amazing! Placing mice in low air pressure every other day slows hair loss, weight gain, osteoporosis & extends median lifespan by 12%. Ascribed to the killing of senescent, zombie cells
Could exercise, high altitude, or a drug have similar benefits? Let’s dig in🧵
Firstly, hypobaric (low) pressure should not to be confused with hyper-baric oxygen therapy (HBOT), which is also studied by longevity researchers, though there may be overlapping hormetic mechanisms between the two @NaturePortfolio
I’ve always wondered if living at a high altitude is healthier, but the evidence is weak. Maybe it needs to be pulsed: high pressure -> low pressure -> high pressure -> low pressure to induce hormesis
CBD, or cannabidiol, is the second most prevalent active ingredient in marijuana, with no effects indicative of any abuse or dependence potential
Mesenchymal stem cells (MSCs) are used to treat various degenerative diseases. Their therapeutic potential is limited by their aging in the dish as they are expanded in number. The researchers tested if CBD could help
This study in 2008 was the first evidence for the information theory of aging in mammals - the idea that DNA breaks and other major stresses cause chromatin modifiers like SIRT1 to relocate, which disrupts the epigenome & changes the expression of genes in ways that cause aging
Just re-read this paper and I’ve realized it was 15 years ahead of its time. Still is