Immune system aging

This 2021 review by three coauthors of Take responsibility for your one precious life – Trained innate immunity cast a wide net:

“Non-specific innate and antigen-specific adaptive immunological memories are vital evolutionary adaptations that confer long-lasting protection against a wide range of pathogens. However, these mechanisms of memory generation and maintenance are compromised as organisms age.

This review discusses how immune function regulates and is regulated by epigenetics, metabolic processes, gut microbiota, and the central nervous system throughout life. We aimed to present a comprehensive view of the aging immune system and its consequences, especially in terms of immunological memory.

aging immune system

A comprehensive strategy is essential for human beings striving to lead long lives with healthy guts, functional brains, and free of severe infections.” “Immune Memory in Aging: a Wide Perspective Covering Microbiota, Brain, Metabolism, and Epigenetics”

Attempts to cover a wide range of topics well are usually uneven. For example, older information in the DNA Methylation In Adaptive Immunity section was followed by a more recent Histone Modifications in Adaptive Immunity section.

This group specializes in tuberculosis vaccine trained immunity studies, and much of what they presented also applied to β-glucan trained immunity. A dozen previously curated papers were cited.


Saving bees by regulating epigenetics

This 2021 study investigated an epigenetic treatment for bees forgetting about their hives:

“Over the last few decades, numbers of both wild and managed bee pollinators have been declining. Although reasons for this decline are under debate, it is highly likely that a combination of multiple stressors is to blame, in particular, deformed wing virus (DWV).

Histone deacetylase inhibitors (HDACi) are a class of compounds which prevent deacetylation of histones and therefore increase gene expression. The present study found that HDACi sodium butyrate (NaB) significantly increased survival and reversed the learning / memory impairment of DWV-infected bees. We demonstrated the mechanism of how epigenetic regulation can resume honeybees’ memory function.

bee survival rates

  • When bees were infected with DWV, 50% of bees died by the end of day 2 and only 10% survived to the end of day 5.
  • When NaB was added to the diet prior to DWV infection, survival rate of DWV-infected bees (N/D group) remained >90% after 5 days.
  • Under laboratory rearing conditions, around 30% of control bees died over a period of 5 days.
  • When NaB was included in uninfected bees’ diet, less than 15% of bees died.

These results indicate that feeding bees with NaB could significantly increase survival with or without DWV infection.” “Real-time monitoring of deformed wing virus-infected bee foraging behavior following histone deacetylase inhibitor treatment”

Interesting that these researchers didn’t attempt to eliminate either the virus cause of bee behavior or parasitical mites that carried the virus. They mainly depended on bees’ endogenous systems providing beneficial responses when stimulated.


Remembering encounters provides future benefits

Two 2021 papers on trained immunity, with the first a review:

“Effective memory immune responses rely on interaction between innate and adaptive immune cells. While activation of innate immunity provides the first line of defense against infections, it also primes the adaptive immune response.

Adaptive immunity can enhance antimicrobial machinery of innate cells, making them more effective at clearing pathogenic microorganisms. An additional layer of complexity adds to this network of interactions, with innate cells adopting a memory phenotype, which used to apply to only adaptive immunity. Furthermore, non-immune cells can develop some features of this memory-like phenotype.


Cell subsets in which trained immunity has been described. Different stimuli including Bacillus Calmette Guerin (BCG), β-glucan, cytokines, cytomegalovirus (CMV), and bacterial components can induce a trained immunity phenotype. A common hallmark of trained immunity in these cases is H3K4me3 in promoters of genes encoding for different cytokines.

  • Mechanisms Underlying Establishment of Trained Immunity
  • Trained Immunity in Neutrophils
  • Trained Immunity in Monocytes and Macrophages: General Features
  • Metabolic Pathways Involved in Training of Monocytes and Macrophages
  • Hormonal Control of Trained Immunity Responses in Monocytes and Macrophages
  • Trained Immunity on Alveolar Macrophages and Involvement of Resident Cells
  • Trained Immunity in NK Cells
  • Trained Immunity in Innate Lymphoid Cells
  • Trained Immunity on Hematopoietic Stem Cells
  • Trained Immunity in Bronchial Epithelial Cells
  • Trained Immunity in Skin Stem Cells
  • Trained Immunity in the Gastrointestinal Tract
  • Immunity Training Against Protozoan-Mediated Pathologies
  • Trained Immunity in Non-Infectious Pathologies

Many gaps of knowledge remain in this field. For example, how long changes associated to trained immunity last, and if, in addition to epigenetic modulation, there are other post-translational modifications on proteins relevant for induction of trained immunity.” “Molecular and Cellular Mechanisms Modulating Trained Immunity by Various Cell Types in Response to Pathogen Encounter”

This second paper was a human study cited for its glutathione findings as follows:

  • “Plasma concentration of IL-1β from BCG-vaccinated individuals are positively associated with serum glutathione concentrations.
  • Trained immunity up-regulates expression of genes involved in glutathione metabolism, suggesting an increase in glutathione synthesis and a higher glutathione recycling rate.
  • Single nucleotide polymorphisms in these genes are associated with changes in pro-inflammatory cytokine production after in vitro training by β-glucan and BCG.

Enzymes whose activities are dependent on glutathione could be used as novel targets to modulate trained immunity.”

IL-1β production

“We found a positive association between plasma glutathione concentration and ex vivo IL-1β production 90 days after BCG vaccination upon in vitro exposure to heterologous stimulus Staphylococcus aureus. Up-regulation of IL-1β production by BCG vaccination was also positively associated with circulating concentrations of other metabolites involved in glutathione metabolism, such as methionine, cysteine, glutamate, and glycine.

GSH metabolism was associated with trained immunity traits in 278 healthy individuals. Trained immunity mechanisms that are shaped by GSH metabolism remain to be further explored.” “Glutathione Metabolism Contributes to the Induction of Trained Immunity”


Broccoli sprout compounds and gut microbiota

Two 2021 reviews from one institution, with this first focused on aliphatic glucosinolates’ (GLS) metabolism to isothiocyanates (ITCs) like sulforaphane:

“Human clinical trials examining efficacy of whole food interventions on cancer prevention targets have shown high levels of inter-individual variation in both absorption and excretion of ITCs. We discuss how consumption of cruciferous vegetables may alter the microbiome, and in turn, influence ITC absorption.

Bioavailability of ITCs from GLS has been shown to be greatly impacted by processing before ingestion. When ITCs are given preformed, they possess the greatest level of bioavailability and are readily absorbed by humans.

Studies have indicated that without plant-derived myrosinase, the gut microbiome is essential for conversion of GLS to ITCs. Without conversion to ITCs, GLS are biologically inert.

There are two different intervals in time when GLS metabolism occurs in the large intestine:

  1. Metabolism of GLS directly following consumption when GLS are not absorbed in the small intestine; and
  2. When GLS are absorbed in the small intestine and go through enterohepatic circulation, returning as GLS in the gut where factors influencing microbial metabolism (such as food matrix, pH, and other compounds present) may be different from the first interval.

This list of bacterial genera altered by cruciferous vegetable consumption focuses on studies completed in healthy individuals and animal models:

Metabolic Fate of Dietary Glucosinolates and Their Metabolites:

Clinical trials have shown that consumption of a diet rich in cruciferous vegetables, compared to a cruciferous vegetable devoid diet, significantly alters composition of the gut microbiome. Each individual responded uniquely to cruciferous vegetable consumption, suggesting that basal microbiome composition may impact outcome.

Understanding the gut microbiome’s role in GLS metabolism, specifically GLS conversion to ITCs, is important to understanding drivers of inter-individual variation . Translating chemopreventative properties of cruciferous vegetables from the lab bench to the clinic requires addressing factors that drive high variability in ITC absorption and excretion observed in clinical trials.” “Metabolic Fate of Dietary Glucosinolates and Their Metabolites: A Role for the Microbiome”

Discussion of indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM) was passed over to this second review:

“Hydrolysis of glucobrassicin GLS by plant or bacterial myrosinase produces multiple indoles, predominantly I3C. Yield of I3C from glucobrassicin is about 20%.

In the stomach, I3C undergoes extensive condensation to yield predominately DIM. Ingestion of I3C results in 20–40% conversion to DIM.

DIM has multiple mechanisms of action, the most well-characterized is modulation of aryl hydrocarbon receptor (AHR) signaling. The DIM-intestinal AHR-microbiome axis is an important component for future development of a personalized nutraceutical approach to achieving optimal health.” “Indoles Derived From Glucobrassicin: Cancer Chemoprevention by Indole-3-Carbinol and 3,3′-Diindolylmethane”

DIM estimates in this second review were too high with respect to clinical trial findings of Eat broccoli sprouts for DIM. Using the trial’s 21.61 μmol of average glucobrassicin intake, this review’s 20% I3C yield would be 4.32 μmol. This review’s lowest 20% DIM yield from I3C would be 0.86 μmol, representing a 4.0% DIM bioavailability from glucobrassicin intake.

The trial’s lowest average DIM (in postmenopausal women) after 35 days of eating broccoli sprouts measured 0.5544 μmol, representing an average 2.57% DIM bioavailability from glucobrassicin intake. One of the trial’s coauthors officially reviewed this second review, but he didn’t insist on better human in vivo estimates, although 4.0 / 2.57 is more than 50% too high for the review’s lowest DIM estimate.

The trial and its parent trial also weren’t cited by either review. Aren’t human clinical trials measuring sulforaphane, sulforaphane metabolites, and DIM bioavailability relevant to “Metabolic Fate of Dietary Glucosinolates and Their Metabolites” and “Indoles Derived From Glucobrassicin”?

Something else was missing from both papers. They had academic suggestions for future studies, but neither one continued on to say “and here’s what we’re sponsored to do to fill these gaps.”


Gut microbiota and critical development periods

This 2021 rodent study focused on global histone acetylation as a model to understand roles of microbially produced short-chain fatty acids in liver function:

“Despite the utility of germ-free mice in probing complex interactions between gut microbiota and host physiology, germ-free mice are developmentally, physiologically, and metabolically unique when compared with their conventionally housed counterparts. We sought to determine whether antibiotic-mediated microbiota depletion would affect global hepatic histone acetylation states through SCFA-dependent mechanisms, as previously observed in germ-free mice.

The inability of antibiotic-mediated microbiota depletion to recapitulate findings observed in germ-free mice suggests that the transition from a germ-free to a colonized mouse leads to resilient alterations in hepatic histone acetylation states that cannot be altered by further modulating the microbial environment. This finding is distinct from other germ-free phenotypes that are considered to be partially reversible, with clear alterations in their function observed after antibiotic treatment.

histone acetylation

Comparing antibiotic-treated and untreated mice that both received CCl4 at 24 and 48 hours after injury, there were almost no histone acetylation differences. This demonstrates that hepatic injury leads to a global shift in histone acetylation that is primarily independent of gut microbiota.

Major chromatin reorganization driven by histone acetylation leads to markers of differentiation, and addition of targeted differentiation signals induces events to stabilize these histone acetylation patterns – a key feature of embryonic development and terminal cellular differentiation. Differences in histone acetylation patterns seen between germ-free and conventionally raised mice may be a developmental-like effect of hepatocytes not yet exposed to microbial by-products.

Results suggest that microbial and dietary modifications to the gut microbiome in conventionally raised mice are not a means to modulate global hepatic histone acetylation. Microbiota-dependent landscaping of the hepatic epigenome appears static in nature, while the hepatic transcriptome is responsive to alterations in the gut microbiota, yet independent of global histone acetylation.

Findings underscore significant differences between these model systems that should be taken into account when considering their relevance to human biology.” “Global Microbiota-Dependent Histone Acetylation Patterns Are Irreversible and Independent of Short Chain Fatty Acids” (not freely available) Thanks to Dr. Elliot S. Friedman for providing a copy.

1. By describing “a key feature of embryonic development,” this study provided a gut microbiota-liver analogy of critical periods. If developmental events don’t happen when they are required, it’s probable that their window is missed, and won’t reopen later for a second chance at normalizing.

2. Many studies used a germ-free animal model, such as:

This study provided evidence for a limitation of this model, especially when extrapolating germ-free animal results to humans without similarly testing humans.


Natural products vs. neurodegenerative diseases

I was recently asked about taking rapamycin for its effects on mTOR. I replied that diet could do the same thing. Here’s a 2021 review outlining such effects:

“As common, progressive, and chronic causes of disability and death, neurodegenerative diseases (NDDs) significantly threaten human health, while no effective treatment is available. Recent studies have revealed the role of phosphoinositide 3-kinase (PI3K)/Akt (Protein kinase B)/mammalian target of rapamycin (mTOR) in some diseases and natural products with therapeutic potentials.

Growing evidence highlights the dysregulated PI3K/Akt/mTOR pathway and interconnected mediators in pathogenesis of NDDs. Side effects and drug-resistance of conventional neuroprotective agents urge the need for providing alternative therapies.


Polyphenols, alkaloids, carotenoids, and terpenoids have shown to be capable of a great modulation of PI3K/Akt/mTOR in NDDs. Natural products potentially target various important oxidative/inflammatory/apoptotic/autophagic molecules/mediators, such as Bax, Bcl-2, p53, caspase-3, caspase-9, NF-κB, TNF-α, GSH, SOD, MAPK, GSK-3β, Nrf2/HO-1, JAK/STAT, CREB/BDNF, ERK1/2, and LC3 towards neuroprotection.

This is the first systematic and comprehensive review with a simultaneous focus on the critical role of PI3K/Akt/mTOR in NDDs and associated targeting by natural products.” “Natural products attenuate PI3K/Akt/mTOR signaling pathway: A promising strategy in regulating neurodegeneration” (not freely available) Thanks to Dr. Sajad Fakhri for providing a copy.

Natural products mentioned in this review that I eat in everyday foods are listed below. The most effective ones are broccoli and red cabbage sprouts, and oats and oat sprouts:

  • Artichokes – luteolin;
  • Blackberries – anthocyanins;
  • Blueberries – anthocyanins, gallic acid, pterostilbene;
  • Broccoli and red cabbage sprouts – anthocyanins, kaempferol, luteolin, quercetin, sulforaphane;
  • Carrots – carotenoids;
  • Celery – apigenin, luteolin;
  • Green tea – epigallocatechin gallate;
  • Oats and oat sprouts – avenanthramides;
  • Strawberries – anthocyanins, fisetin;
  • Tomatoes – fisetin.

Four humpback whales



All about vasopressin

This 2021 review subject was vasopressin:

“Vasopressin is a ubiquitous molecule playing an important role in a wide range of physiological processes, thereby implicated in pathomechanisms of many disorders. The most striking is its central effect in stress-axis regulation, as well as regulating many aspects of our behavior.

Arginine-vasopressin (AVP) is a nonapeptide that is synthesized mainly in the supraoptic, paraventricular (PVN), and suprachiasmatic nucleus of the hypothalamus. AVP cell groups of hypothalamus and midbrain were found to be glutamatergic, whereas those in regions derived from cerebral nuclei were mainly GABAergic.

In the PVN, AVP can be found together with corticotropin-releasing hormone (CRH), the main hypothalamic regulator of the HPA axis. The AVPergic system participates in regulation of several physiological processes, from stress hormone release through memory formation, thermo- and pain regulation, to social behavior.

vasopressin stress axis

AVP determines behavioral responses to environmental stimuli, and participates in development of social interactions, aggression, reproduction, parental behavior, and belonging. Alterations in AVPergic tone may be implicated in pathology of stress-related disorders (anxiety and depression), Alzheimer’s, posttraumatic stress disorder, as well as schizophrenia.

An increasing body of evidence confirms epigenetic contribution to changes in AVP or AVP receptor mRNA level, not only during the early perinatal period, but also in adulthood:

  • DNA methylation is more targeted on a single gene; and it is better characterized in relation to AVP;
  • Some hint for bidirectional interaction with histone acetylation was also described; and
  • miRNAs are implicated in the hormonal, peripheral role of AVP, and less is known about their interaction regarding behavioral alteration.” “Epigenetic Modulation of Vasopressin Expression in Health and Disease”

Find your way, regardless of what the herd does.


Take taurine for your mitochondria

This 2021 review summarized taurine’s beneficial effects on mitochondrial function:

“Taurine supplementation protects against pathologies associated with mitochondrial defects, such as aging, mitochondrial diseases, metabolic syndrome, cancer, cardiovascular diseases and neurological disorders. Potential mechanisms by which taurine exerts its antioxidant activity in maintaining mitochondria health include:

  1. Conjugates with uridine on mitochondrial tRNA to form a 5-taurinomethyluridine for proper synthesis of mitochondrial proteins (mechanism 1), which regulates the stability and functionality of respiratory chain complexes;
  2. Reduces superoxide generation by enhancing the activity of intracellular antioxidants (mechanism 2);
  3. Prevents calcium overload and prevents reduction in energy production and collapse of mitochondrial membrane potential (mechanism 3);
  4. Directly scavenges HOCl to form N-chlorotaurine in inhibiting a pro-inflammatory response (mechanism 4); and
  5. Inhibits mitochondria-mediated apoptosis by preventing caspase activation or by restoring the Bax/Bcl-2 ratio and preventing Bax translocation to the mitochondria to promote apoptosis.

taurine mechanisms

An analysis on pharmacokinetics of oral supplementation (4 g) in 8 healthy adults showed a baseline taurine content in a range of 30 μmol to 60 μmol. Plasma content increased to approximately 500 μmol 1.5 h after taurine intake. Plasma content subsequently decreased to baseline level 6.5 h after intake.

We discuss antioxidant action of taurine, particularly in relation to maintenance of mitochondria function. We describe human studies on taurine supplementation in several mitochondria-associated pathologies.” “The Role of Taurine in Mitochondria Health: More Than Just an Antioxidant”

I take a gram of taurine at breakfast and at dinner along with other supplements and 3-day-old Avena sativa oat sprouts. Don’t think my other foods’ combined taurine contents are more than one gram, because none are found in various top ten taurine-containing food lists.

As a reminder, your mitochondria came from your mother, except in rare cases.

A time to speak

“To every thing there is a season, and a time to every purpose under heaven:
A time to break down, and a time to build up;
A time to mourn, and a time to dance;
A time to embrace, and a time to refrain from embracing;
A time to keep silent, and a time to speak.”

A review from 2017:

“Few, if any, other drugs can rival ivermectin for its beneficial impact on human health and welfare. Perhaps more than any other drug, ivermectin is a drug for the world’s poor. For most of this century, some 250 million people have been taking it.

The following are an indication of disease-fighting potential that has been identified for ivermectin thus far:

  • Antiviral – Ivermectin has been found to potently inhibit replication of yellow fever virus, with EC50 values in the sub-nanomolar range. It inhibits replication in several other flaviviruses, including dengue, Japanese encephalitis, and tick-borne encephalitis. Ivermectin interrupts virus replication. It demonstrates antiviral activity against several RNA viruses by blocking nuclear trafficking of viral proteins. It has been shown to have potent antiviral action against HIV-1.
  • Asthma – Ivermectin suppressed mucus hypersecretion by goblet cells, establishing that ivermectin can effectively curb inflammation, such that it may be useful in treating allergic asthma and other inflammatory airway diseases.
  • Bedbugs – Ivermectin is highly effective against bedbugs, capable of eradicating or preventing bedbug infestations.
  • Disease vector control – Ivermectin is highly effective in killing a broad range of insects. Comprehensive testing against 84 species of insects showed that avermectins were toxic to almost all insects tested. At sub-lethal doses, ivermectin inhibits feeding and disrupts mating behavior, oviposition, egg hatching, and development.
  • Malaria – Mosquitoes that transmit Plasmodium falciparum, the most dangerous malaria-causing parasite, can be killed by ivermectin present in the human bloodstream after a standard oral dose.
  • Myiasis – Myiasis is an infestation of fly larvae that grow inside the host. Oral myiasis has been successfully treated with ivermectin, which has also been effective as a non-invasive treatment for orbital myiasis, a rare and preventable ocular morbidity.
  • Schistosomiasis – Schistosoma species are the causative agent of schistosomiasis, a disease afflicting more than 200 million people worldwide. Ivermectin helps control one of the world’s major neglected tropical diseases.
  • Trichinosis – Globally, approximately 11 million individuals are infected with Trichinella roundworms. Ivermectin kills Trichinella spiralis, the species responsible for most of these infections.” “Ivermectin: enigmatic multifaceted ‘wonder’ drug continues to surprise and exceed expectations”

72 citations in CrossRef. Didn’t see citing 2020-2021 papers that noted any safety concerns when administered at proper doses.

Train your immune system every day, because:

“Rapid clearance following ivermectin dosing, results not from direct impact of the drug, but via suppression of a parasite’s ability to evade the host’s natural immune defense mechanisms.”

It’s safe, and it’s effective. Ivermectin’s main difficulty is that its patent expired in 1997.


Gut and brain health

This 2021 human review subject was interactions of gut health and disease with brain health and disease:

“Actions of microbial metabolites are key for appropriate gut-brain communication in humans. Among these metabolites, short-chain fatty acids (SCFAs), tryptophan, and bile acid metabolites / pathways show strong preclinical evidence for involvement in various aspects of brain function and behaviour.

Dietary fibres, proteins, and fats ingested by the host contain components which are metabolized by microbiota. SCFAs are produced from fermentation of fibres, and tryptophan-kynurenine (TRP-KYN) metabolites from dietary proteins. Primary bile acids derived from liver metabolism aid in lipid digestion, but can be deconjugated and bio-transformed into secondary bile acids.


One of the greatest challenges with human microbiota studies is making inferences about composition of colonic microbiota from faeces. There are known differences between faecal and caecal microbiota composition in humans along with spatial variation across the gastrointestinal tract.

It is difficult to interpret microbiome-host associations without identifying the driving influence in such an interaction. Large cohort studies may require thousands of participants on order to reach 20 % explanatory power for a certain host-trait with specific microbiota-associated metrics (Shannon diversity, relative microbial abundance). Collection of metadata is important to allow for a better comparison between studies, and to identify differentially abundant microbes arising from confounding variables.” “Mining Microbes for Mental Health: Determining the Role of Microbial Metabolic Pathways in Human Brain Health and Disease”

Don’t understand why these researchers handcuffed themselves by only using PubMed searches. For example, two papers were cited for:

“Conjugated and unconjugated bile acids, as well as taurine or glycine alone, are potential neuroactive ligands in humans.”

Compare scientific coverage of PubMed with Scopus:

  • 2017 paper: PubMed citations 39; Scopus citations 69.
  • 2019 paper: PubMed citations 69; Scopus citations 102.

Large numbers of papers intentionally missing from PubMed probably influenced this review’s findings, such as:

  1. “There are too few fibromyalgia and migraine microbiome-related studies to make definitive conclusions. However, one fibromyalgia study found altered microbial species associated with SCFA and tryptophan metabolism, as well as changes in serum levels of SCFAs. Similarly, the sole migraine-microbiota study reported an increased abundance of the kynurenine synthesis GBM (gut-brain module).
  2. Due to heterogeneity of stroke and vascular disease conditions, it is difficult to make substantial comparisons between studies. There is convincing evidence for involvement of specific microbial genera / species and a neurovascular condition in humans. However, taxa were linked to LPS biosynthesis rather than SCFA production.
  3. Several studies suggest lasting microbial changes in response to prenatal or postnatal stress, though these do not provide evidence for involvement of SCFA, tryptophan, or bile-acid modifying bacteria. Similar to stress, there are very few studies assessing impact of post-traumatic stress disorder on microbiota.”

These researchers took on a difficult task. Their study design could have been better.




Take acetyl-L-carnitine for early-life trauma

This 2021 rodent study traumatized female mice during their last 20% of pregnancy, with effects that included:

  • Prenatally stressed pups raised by stressed mothers had normal cognitive function, but depressive-like behavior and social impairment;
  • Prenatally stressed pups raised by control mothers did not reverse behavioral deficits; and
  • Control pups raised by stressed mothers displayed prenatally stressed pups’ behavioral phenotypes.

Acetyl-L-carnitine (ALCAR) protected against and reversed depressive-like behavior induced by prenatal trauma:

alcar regime

ALCAR was supplemented in drinking water of s → S mice either from weaning to adulthood (3–8 weeks), or for one week in adulthood (7–8 weeks). ALCAR supplementation from weaning rendered s → S mice resistant to developing depressive-like behavior.

ALCAR supplementation for 1 week during adulthood rescued depressive-like behavior. One week after ALCAR cessation, however, the anti-depressant effect of ALCAR was diminished.

Intergenerational trauma induces social deficits and depressive-like behavior through divergent and convergent mechanisms of both in utero and early-life parenting environments:

  • We establish 2-HG [2-hydroxyglutaric acid, a hypoxia and mitochondrial dysfunction marker, and an epigenetic modifier] as an early predictive biomarker for trauma-induced behavioral deficits; and
  • Demonstrate that early pharmacological correction of mitochondria metabolism dysfunction by ALCAR can permanently reverse behavioral deficits.” “Intergenerational trauma transmission is associated with brain metabotranscriptome remodeling and mitochondrial dysfunction”

Previously curated studies cited were:

This study had an effusive endorsement of acetyl-L-carnitine in its Discussion section, ending with:

“This has the potential to change lives of millions of people who suffer from major depression or have risk of developing this disabling disorder, particularly those in which depression arose from prenatal traumatic stress.”

I take a gram daily. Don’t know about prenatal trauma, but I’m certain what happened during my early childhood.

I asked both these researchers and those of Reference 70 for their estimates of a human equivalent to “0.3% ALCAR in drinking water.” Will update with their replies.


The brainstem’s parabrachial nucleus

I often reread blog posts that you read. Yesterday, a reader clicked Treat your gut microbiota as one of your organs. On rereading, I saw that I didn’t properly reference the parabrachial nucleus as being part of the brainstem.

A “parabrachial nucleus” search led me to a discussion of two 2020 rodent studies:

“Nociceptive signals entering the brain via the spinothalamic pathway allow us to detect location and intensity of a painful sensation. But, at least as importantly, nociceptive inputs also reach other brain regions that give pain its emotional texture.

Key to that circuitry is the parabrachial nucleus (PBN), a tiny cluster of cells in the brainstem associated with homeostatic regulation of things like temperature and food intake, response to aversive stimuli, and perceptions of many kinds. Two new papers advance understanding of PBN’s role in pain:

  1. The PBN receives inhibitory inputs from GABAergic neurons in the central nucleus of the amygdala (CeA). Those inputs are diminished in chronic pain conditions, leading to PBN hyperactivity and increased pain perception. Disinhibition of the amygdalo-parabrachial pathway may be crucial to establishing chronic pain.
  2. The dorsal PBN is the first receiver of spinal nociceptive input. It transmits certain inputs to the ventral medial hypothalamus and lateral periaqueductal gray. Certain of its neurons transmit noxious inputs to the external lateral PBN, which then transmits those inputs to the CeA and bed nucleus of the stria terminalis. This is quite new, that nociceptive information the CeA receives has already been processed by the PBN. They measured many pain-related behaviors: place aversion, avoidance, and escape. That allowed them to dissect different pain-related behaviors in relation to distinct subnuclei of the PBN.


Chronic pain is manufactured by the brain. It’s not a one-way process driven by something coming up from the periphery. The brain is actively constructing a chronic pain state in part by this recurring circuit.

A role of the PBN is to sound an alarm when an organism is in danger, but its roles go further. It is a key homeostatic center, weighing short-term versus long-term survival. If you’re warm, fed, and comfortable, organisms can address long-term directives like procreation. When you’re unsafe, though, you need to put those things off and deal with the emergency.” “The Parabrachial Nucleus Takes the Pain Limelight” “An Amygdalo-Parabrachial Pathway Regulates Pain Perception and Chronic Pain” “Divergent Neural Pathways Emanating from the Lateral Parabrachial Nucleus Mediate Distinct Components of the Pain Response”

Two dozen papers have since cited these two studies. One that caught my eye was a 2021 rodent study:

“Migraines cause significant disability and contribute heavily to healthcare costs. Irritation of the meninges’ outermost layer (the dura mater), and trigeminal ganglion activation contribute to migraine initiation.

Dura manipulation in humans during neurosurgery is often painful, and dura irritation is considered an initiating factor in migraine. In rodents, dura irritation models migraine-like symptoms.

Maladaptive changes in central pain-processing regions are also important in maintaining pain. The parabrachial complex (PB) receives diverse sensory information, including a direct input from the trigeminal ganglion.

PB-projecting trigeminal ganglion neurons project also to the dura. These neurons represent a direct pathway between the dura, a structure implicated in migraine, and PB, a key node in chronic pain and aversion.” “Parabrachial complex processes dura inputs through a direct trigeminal ganglion-to-parabrachial connection”


The amino acid ergothioneine

A trio of papers on ergothioneine starts with a 2019 human study. 3,236 people without cardiovascular disease and diabetes mellitus ages 57.4 ± 6.0 were measured for 112 metabolites, then followed-up after 20+ years:

“We identified that higher ergothioneine was an independent marker of lower risk of cardiometabolic disease and mortality, which potentially can be induced by a specific healthy dietary intake.

overall mortality and ergothioneine

Ergothioneine exists in many dietary sources and has especially high levels in mushrooms, tempeh, and garlic. Ergothioneine has previously been associated with a higher intake of vegetables, seafood and with a lower intake of solid fats and added sugar as well as associated with healthy food patterns.” “Ergothioneine is associated with reduced mortality and decreased risk of cardiovascular disease”

I came across this study by its citation in a 2021 review:

“The body has evolved to rely on highly abundant low molecular weight thiols such as glutathione to maintain redox homeostasis but also play other important roles including xenobiotic detoxification and signalling. Some of these thiols may also be derived from diet, such as the trimethyl-betaine derivative of histidine, ergothioneine (ET).

image description

ET can be found in most (if not all) tissues, with differential rates of accumulation, owing to differing expression of the transporter. High expression of the transporter, and hence high levels of ET, is observed in certain cells (e.g. blood cells, bone marrow, ocular tissues, brain) that are likely predisposed to oxidative stress, although other tissues can accumulate high levels of ET with sustained administration. This has been suggested to be an adaptive physiological response to elevate ET in the damaged tissue and thereby limit further injury.” “Ergothioneine, recent developments”

The coauthors of this review were also coauthors of a 2018 review:

“Ergothioneine is avidly taken up from the diet by humans and other animals through a transporter, OCTN1. Ergothioneine is not rapidly metabolised, or excreted in urine, and has powerful antioxidant and cytoprotective properties.

ergothioneine in foods

Effects of dietary ET supplementation on oxidative damage in young healthy adults found a trend to a decrease in oxidative damage, as detected in plasma and urine using several established biomarkers of oxidative damage, but no major decreases. This could arguably be a useful property of ET: not interfering with important roles of ROS/RNS in healthy tissues, but coming into play when oxidative damage becomes excessive due to tissue injury, toxin exposure or disease, and ET is then accumulated.” “Ergothioneine – a diet-derived antioxidant with therapeutic potential”

I’m upping a half-pound of mushrooms every day to 3/4 lb. (340 g). Don’t think I could eat more garlic than the current six cloves.


I came across this subject in today’s video:

Does sulforaphane treat autism?

A 2021 human study investigated sulforaphane treatments of autistic 3-to-12-year-olds:

“Sulforaphane (SF) led to non-statistically significant changes in the total and all subscale scores of the primary outcome measure. Several effects of SF on biomarkers correlated to clinical improvements. SF was very well tolerated and safe and effective based on our secondary clinical measures.


Clinical response to SF was associated with changes in mitochondrial function, and large intrasubject variability in this study was linked to underlying biological responses. The increase in ATP [adenosine triphosphate]-Linked Respiration associated with improvement in ABC [Aberrant Behavior Checklist] scores suggests that those individuals who showed improvements in behavior also had improved mitochondrial capacity to produce ATP.

Individuals who showed an improvement in ABC scores also showed a decrease in Proton Leak Respiration, suggesting that their mitochondria were better able to regulate oxidative stress. It is also possible that the increase in ATP production was related to improvement in the ability of mitochondria to handle oxidative stress.

SF had significant positive effects on oxidative stress, cytoprotective markers and cytokines, as well as mitochondrial function. These were promising findings that require further investigation of both clinical effects and mechanisms of action of SF.” “Randomized controlled trial of sulforaphane and metabolite discovery in children with Autism Spectrum Disorder”

Differences between this clinical trial and its pilot study curated in Autism biomarkers and sulforaphane included:

“HO-1 [heme oxygenase 1] functions to couple activation of mitochondrial biogenesis to anti-inflammatory cytokine expression. It was initially increased in the pilot study, then paradoxically decreased in the main study, on continued treatment for longer periods with SF.

Increased HO-1 is consistent with decreases in proinflammatory cytokines we observed initially in IL-6, IL-1β and TNF-α. Decreased levels of cytokines continued after HO-1 returned to baseline with longer duration of treatment and suggest a decreased inflammatory state.

These cytokines are usually elevated in children with ASD, but were decreased on treatment with SF: IL-6 and TNF-α at 15 (but not 30) weeks.”

This study made a good effort with autistic children. Its insignificant effects of sulforaphane treatments pointed toward an understanding that human experiences when we are fetuses can override many subsequent events, treatments, and life experiences.

Several diseases, one treatment?

This 2021 review summarized three dietary supplements’ effects on psychiatric symptoms:

“Upregulation of Nrf2 has been suggested as a common therapeutic target for major neuropsychiatric disorders. In this paper, evidence is presented showing how NAC [N-acetyl-cysteine], coenzyme Q10 (CoQ), and melatonin can ameliorate many important effects of oxidative stress by upregulating Nrf2.

Given its key role in governing cellular antioxidant response, upregulation of Nrf2 has been suggested as a common therapeutic target in neuropsychiatric illnesses such as major depressive disorder, bipolar disorder, and schizophrenia. These are associated with chronic oxidative and nitrosative stress, characterised by elevated levels of reactive oxygen species, nitric oxide, and peroxynitrite.


  • Acts as a superoxide scavenger in neuroglial mitochondria;
  • Instigates mitohormesis;
  • Ameliorates lipid peroxidation in the inner mitochondrial membrane;
  • Activates uncoupling proteins;
  • Promotes mitochondrial biogenesis; and
  • Has positive effects on the plasma membrane redox system.


  • Scavenges mitochondrial free radicals;
  • Inhibits mitochondrial nitric oxidesynthase;
  • Restores mitochondrial calcium homeostasis;
  • Deacetylates and activates mitochondrial SIRT3;
  • Ameliorates increased permeability of the blood-brain barrier and intestine; and
  • Counters neuroinflammation and glutamate excitotoxicity.” “Increasing Nrf2 Activity as a Treatment Approach in Neuropsychiatry” (registration required)

These reviewers explored three selected supplements, citing 380 references. They overlooked something, though. There was only one mention of sulforaphane in their paper, yet four references’ titles included sulforaphane?

I take two of the three exogenous supplements discussed. The one I stopped taking over a year ago – NAC – was thoroughly discussed, but not in contexts directly related to the Nrf2 transcription factor. Why?

Switch on your Nrf2 signaling pathway pointed out:

“We use NAC in the lab all the time because it stops an Nrf2 activation. So that weak pro-oxidant signal that activates Nrf2, you switch it off by giving a dose of NAC. It’s a potent antioxidant in that right, but it’s blocking signalling. And that’s what I don’t like about its broad use.”

The current review noted that Nrf2 is activated by oxidative stress. NAC is a precursor to glutathione – our main endogenous antioxidant – and neither one activates Nrf2 pathways.

What does? Sulforaphane.