Endotoxemia and Blood Brain Barrier Dysfunction
I stood on the balcony overlooking Biscayne Bay and Star Island. A cruise ship bellowed as she lumbered out of port, packed full of what looked from afar to be half the population of Missouri waving farewell. There was a full-sized water park sprawled across the top deck upon which I could see a several hundred person line already forming, climbing up three stories to reach the main waterslide. The pee South Park episode… my god. A recent viral video came to mind— one of these cruises apparently had had to return to land shortly after its departure because a huge brawl had broken out in the buffet line, something which had become an all-too-common occurrence lately. The ship was so massive it was hard to tell if it itself was moving or the entire foreground was starting to shift. Maybe I had dropped a bit too much CBD. That had been the point, though. CBD and a blend of ashwagandha, holy basil, rhodiola and a few other herbs that blunted cortisol-- the true origins of the "low cortisol" trend hijacked by Clav and the myriad other looksmaxxing feds. A little rest and regeneration before returning North completely revitalized and ready to begin training for the cross country ski season. However, with my newly discovered understanding of Calhoun's behavioral sink, I knew venturing into the urban biome was playing with fire. This was only a half-serious concern, though, and just as much a personally entertaining plot line I had been using lately to frame experiences that consistently failed to meet expectations. After all, rats and humans are totally different… right? What little remained of my inner optimist said yes; the Germanic cynic remained silent, smiling wryly. All of those people… all of that feces… I wondered where it all went…
Overview
In the previous blog, we learned about how dysbiosis leads to decreased short-chain fatty acid (SCFA) production and gut permeability. When lipopolysaccharides (LPS) produced by gram-negative bacteria breach the gut epithelium, they enter the bloodstream and travel throughout the body, eventually reaching the brain vasculature. However, before gaining access to the brain parenchyma, these endotoxins must penetrate a second line of defense— the blood brain barrier (BBB). The BBB is the layer of endothelial cells on the inside of the blood vessels of the brain which prevents unwanted bacteria, viruses, toxins and various blood components from passing from peripheral circulation into the central nervous system and causing damage. In inflammatory states, such as LPS-induced endotoxemia, the BBB becomes permeable and can be penetrated by plasma components that cause oxidative stress and activation of immune cells in the brain called microglia. If this immune response becomes chronic, it culminates in neuronal apoptosis and loss of gray matter in the brain.
NF-κB: the master regulator of inflammation
White blood cells (WBCs, leukocytes) like monocytes and neutrophils are the first responders in sounding the alarm when LPS makes its way into the bloodstream. These WBCs express a large number of toll-like receptor 4 (TLR4) proteins which recognize and bind to endotoxins and other pathogens in the plasma. TLR4 expression is widespread across immune cells; it activates nuclear factor kappa beta (NF-κB) gene transcription, the master regulator in charge of initiating pro-inflammatory cytokine production. LPS binds to additional TLR4 receptors on the endothelium, initiating the same process of NF-κB mediated cytokine release which recruits more immune cells and amplifies the inflammatory response.
In neutrophils, the most common white blood cell, TLR4 activation prompts the release of myeloperoxidase (MPO), a hydrogen peroxide based bleach that kills bacteria. MPO functions like carpet bombing— it’s a scorched-earth strategy that can end up causing a lot of collateral damage, especially to the glycocalyx which we’ll get to in a second. Most are familiar with “inflammation”, but if you actually asked what this inflammation is, few would be able to provide an answer outside of the still vague “oxidative stress”. At the most basic level, pro-inflammatory cytokines tell mitochondria to shift towards a glycolytic state in which less oxygen is consumed and more reactive oxygen species and lactate are produced. This is protective in the short term, but causes problems if it becomes chronic.
How does the glycocalyx structure EZ water to protect the blood brain barrier?
Similar to the mucosal lining of the gut, all blood vessels have a protective barrier on their luminal (inside) surfaces— including those that make up the BBB. This barrier is called the glycocalyx. It prevents RBCs, WBCs, blood proteins, cholesterol and other blood components from coming into direct contact with the endothelial lining and initiating an inflammatory response. The glycocalyx is composed of carbohydrate chains called glycosaminoglycans (GAGs) primarily consisting of heparin sulfate and hyaluronic acid. These highly sulfated sugars form a hair-like coating which carries a negative electrostatic charge and allows for the repulsion of negatively charged plasma components like RBCs and WBCs— similar to how magnets repel each other if both negative poles are facing.
Circadian OGs might recall that this electrostatic charge is also what helps structure exclusion zone water (EZ water), the gel-like “fourth phase” of water which makes up 99% of glycocalyx volume and, among other things, promotes healthy circulation. As the body is highly selective in what it allows to reach the brain, the glycocalyx of the BBB is thicker and carries a greater negative charge— this is relative to the 5x greater number of mitochondria within the BBB endothelial cells in comparison to peripheral tissues. When pro-inflammatory cytokines induce a shift in these endothelial cells towards glycolytic metabolism, electrons back up and escape mitochondrial electron transport to form reactive oxygen species like superoxide (O2-). This process begins to disrupt nitric oxide (NO), one of the main players in glycocalyx function.
How does nitric oxide production increase shear stress?
Within the glycocalyx matrix, an enzyme called endothelial nitric oxide synthase (eNOS) produces endothelial NO in response to sensing high blood flow, also referred to as shear stress. When NO is released, it promotes vasodilation and healthy blood flow. Just as the glycocalyx density/charge is relative to the underlying mitochondrial function within the endothelial cells of the BBB, so is eNOS expression. Think back to the images we’ve seen of RBCs under a microscope before and after a grounding session. Prior to, they are clumped together like stacks of coins (Rouleaux formations); after, they are free flowing and evenly spaced. This is because grounding, along with everything else that boosts redox (like the CLRLY protocol!), increases sulfation of GAGs within the glycocalyx which supports a larger exclusion zone conducive to NO production and optimal blood flow. Under highly oxidative conditions like endotoxemia, O2- binds to NO and forms the highly reactive nitrogen radical, peroxynitrite (ONOO-). This not only depletes NO availability but oxidizes important cofactors eNOS needs to function. In this situation, rather than pumping out NO, eNOS becomes “uncoupled” and begins to release its own O2- radicals that contribute to the inflammatory cascade.
How do low levels of nitric oxide impair glycocalyx function?
The decrease in available NO causes blood vessels to contract and shear stress to drop. Think high blood pressure. Simultaneously, the increased free radical production consumes extracellular superoxide dismutase (SOD), the primary antioxidant found within the branches of the glycocalyx, which makes the GAGs more susceptible to damage and decreases their net negative charge. Also take into account the collateral damage to the glycocalyx as a result of the ongoing neutrophil-MPO blitzkrieg. Consequently, the exclusion zone becomes smaller and blood components like RBCs and WBCs begin to brush up against the glycocalyx, shearing off portions of it and further decreasing its structural integrity. As this vicious cycle continues, the glycocalyx thins and more endotoxins are able to bind TLR4 receptors on the endothelial lining to activate NF-κB. This is also the mechanism by which cholesterol deposits and progresses into atherosclerosis. Similar to the gut epithelial lining, inflammation destabilizes the tight junction proteins between the neurovascular endothelial cells and results in BBB permeability. In a controlled immune response, this allows WBCs like monocytes that are in the bloodstream to cross the BBB and assist in mitigating the antigenic threat. However, when blood factors access the brain parenchyma, another major immune component is activated— the microglia.
Do covid vaccines cause "long covid"?
A brief aside. Loss of the glycocalyx is central to covid, vaccine injury and “long covid” pathologies. The covid viral strains have a spike protein on their exterior that binds to ACE2 receptors on the endothelium— this is how the virus gains entry into cells. As I warned in 2021, the covid vaccines instruct the body to produce the spike protein for a prolonged period of time. For some, this has been shown to be a few months; for others, years. When the spike protein is able to breach the glycocalyx, it binds ACE2 receptors and activates the renal-aldosterone-angiotensin system (RAAS) which promotes vasoconstriction and the same sequence of events we just covered. You can frame this in a variety of ways: stress, sympathetic activity, inflammation, high blood pressure, immune activation. It’s all the same thing. Over time, continuous spike exposure leads to thymic involution and immunosenescence, which sets the stage for gut permeability and the vicious cycle we are now coming to fully understand. What is long covid? Indefinite production of spike protein by the body combined with a damaged glycocalyx that culminates in BBB permeability. Symptoms like brain fog, depression, low energy are the result of brain atrophy due to chronic pro-inflammatory microglial polarization.
Chronic microglial activation leads to neurodegeneration
Microglia are the octopus-like macrophages of the central nervous system that modulate inflammation and repair mechanisms. They account for about 10% of all brain cells. Under healthy aerobic conditions, microglia express their M2 phenotype. This anti-inflammatory state maintains endothelial tight junctions and BBB integrity and promotes neurogenesis via secretion of brain derived neurotrophic factor (BDNF). However, when LPS penetrates the brain, microglia shift to their M1 pro-inflammatory phenotype— again, via TLR4 > NF-κB pathway. In this state, they produce pro-inflammatory cytokines like IL-6 and TNF-⍺ as well as large amounts of NO. This NO is produced by inducible nitric oxide synthase (iNOS) rather than the beneficial eNOS like in the glycocalyx. This intracellular NO competes with O2 to inhibit complex IV of the mitochondria, acting as direct chemical brake in slowing down the electron transport chain and shifting the cell towards glycolysis and lactate production. Glycolysis is “protection mode”. The excess NO and O2 produced in this state form free radicals intended to eliminate pathogens by sterilizing the immediate vicinity before then triggering repair pathways. However, if this oxidative stress is sustained, it damages neurons and the brain begins to atrophy.
How do SCFAs support blood brain barrier integrity?
What’s good for the gut is good for the brain. Even though about 70% of the short-chain fatty acids produced in the gut are metabolized locally, a portion enter circulation and travel to the brain. The BBB expresses large amounts of monocarboxylate transporters (MCTs) which shuttle SCFAs past the BBB where they are used by endothelial cells and microglia to maintain aerobic respiration. Unlike the gut, the brain uses tons of oxygen to burn sugar to maintain this high metabolic rate; SCFAs are like NOS injections constantly priming an engine already running at high RPMs. In this oxygen-rich environment characterized by low hypoxia inducible factor expression (HIF-1a), microglia maintain either neutral or M2 polarization and produce anti-inflammatory cytokines like TGF-ẞ and IL-10 which signal cell growth and repair— essential for regenerating organ mass and reversing biological age, our number one goal.
In addition to being an energy source, SCFAs like butyrate act as signaling molecules by inhibiting histone deacytelase enzymes (HDACs). To simplify a rather complex subject, HDACs regulate epigenetic expression. When SCFAS inhibit HDACs, antioxidant genes like NRF2 are up-regulated to promote redox and repair, while inflammatory genes like NF-κB are down-regulated, preventing oxidative stress and glycolysis. This is again why getting at least 30 grams or more of dietary fiber every day is of utmost importance. Without it, we lose gram-positive bacteria and SCFA production declines which causes gut and brain barrier permeability. The chronic immune activation which ensues results in loss of gray matter in the brain, and ultimately, behavioral regression— in mice and men alike…
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I made my way down to the pool area and grabbed a chair. A muscled guy with a dark complexion, tattoos and a fade-to-mullet, gold chain combo sat on the edge of the pool on a call. “It’s not just about telling the client what to do, it’s about making the client believe in what he’s doing. You have to get him to buy in, to commit to change. Make it impersonal; if he doesn’t want to improve his life, that’s fine, you’ll walk away and leave him to his own misery. It’s real simple, does he want to lose 15 pounds or continue being a piece of shit?? Now close him!” He hung up and slid into the pool, joining his silicone-enhanced foid. Some sort of MLM coaching program… the memes were coming to life before my very eyes. I relocated to the white sand of the man-made beach overlooking the bay to spare myself from the multitude of loud and “important” phone calls going on poolside, most of which had to do with sky-rocketing real estate prices— the most thoroughly ran-thru topic of the 2020s. As I cooked under the beating Miami sun, gazing across the bay, that foul smell again tickled my olfactory bulb. It was sewage. But not just regular sewage… this had a distinctly sick odor to it. The breeze picked up and cleared the stench before I could ponder its origin and immediately my eyes began to water. Really? I wiped them, got up and looked around. Ahhchoo! Then another sneeze. I could see just below the boardwalk the water was chock full of brown algae. I’d encountered this foul stuff before in St. Pete’s. It was sargassum: the toxic algae that off-gassed ammonia as it decomposed. It was starting to choke out the oceans, being fed by fertilizer run-off and, remembering the cruise ship, probably human excrement. A massive ribbon of algae in the middle of the bay stretched all the way south towards the inlet, probably directly connected to the continent-sized deposit situated in the middle of the Atlantic. $100 mil for one of these spots on Biscayne and you couldn’t even swim in the water? Only a fool would agree to that… But then I stopped myself, realizing that I too was falling prey to the real estate mind virus...
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