Taurine week #7: Brain

Finishing a week’s worth of 2022 taurine research with two reviews of taurine’s brain effects:

“We provide a overview of brain taurine homeostasis, and review mechanisms by which taurine can afford neuroprotection in individuals with obesity and diabetes. Alterations to taurine homeostasis can impact a number of biological processes such as osmolarity control, calcium homeostasis, and inhibitory neurotransmission, and have been reported in both metabolic and neurodegenerative disorders.

Models of neurodegenerative disorders show reduced brain taurine concentrations. On the other hand, models of insulin-dependent diabetes, insulin resistance, and diet-induced obesity display taurine accumulation in the hippocampus. Given cytoprotective actions of taurine, such accumulation of taurine might constitute a compensatory mechanism that attempts to prevent neurodegeneration.

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Taurine release is mainly mediated by volume-regulated anion channels (VRAC) that are activated by hypo-osmotic conditions and electrical activity. They can be stimulated via glutamate metabotropic (mGluR) and ionotropic receptors (mainly NMDA and AMPA), adenosine A1 receptors (A1R), and metabotropic ATP receptors (P2Y).

Taurine mediates its neuromodulatory effects by binding to GABAA, GABAB, and glycine receptors. While taurine binding to GABAA and GABAB is weaker than to GABA, taurine is a rather potent ligand of the glycine receptor. Reuptake of taurine occurs via taurine transporter TauT.

Cytoprotective actions of taurine contribute to brain health improvements in subjects with obesity and diabetes through various mechanisms that improve neuronal function, such as:

  • Modulating inhibitory neurotransmission, which promotes an excitatory–inhibitory balance;
  • Stimulating antioxidant systems; and
  • Stabilizing mitochondria energy production and Ca2+ homeostasis.”

https://www.mdpi.com/2072-6643/14/6/1292/htm “Taurine Supplementation as a Neuroprotective Strategy upon Brain Dysfunction in Metabolic Syndrome and Diabetes”


A second review focused on taurine’s secondary bile acids produced by gut microbiota:

“Most neurodegenerative disorders are diseases of protein homeostasis, with misfolded aggregates accumulating. The neurodegenerative process is mediated by numerous metabolic pathways, most of which lead to apoptosis. Hydrophilic bile acids, particularly tauroursodeoxycholic acid (TUDCA), have shown important anti-apoptotic and neuroprotective activities, with numerous experimental and clinical evidence suggesting their possible therapeutic use as disease-modifiers in neurodegenerative diseases.

Biliary acids may influence each of the following three mechanisms through which interactions within the brain-gut-microbiota axis take place: neurological, immunological, and neuroendocrine. These microbial metabolites can act as direct neurotransmitters or neuromodulators, serving as key modulators of the brain-gut interactions.

The gut microbial community, through their capacity to produce bile acid metabolites distinct from the liver, can be thought of as an endocrine organ with potential to alter host physiology, perhaps to their own favour. Hydrophilic bile acids, currently regarded as important hormones, exert modulatory effects on gut microbiota composition to produce secondary bile acids which seem to bind a number of receptors with a higher affinity than primary biliary acids, expressed on many different cells.

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TUDCA regulates expression of genes involved in cell cycle regulation and apoptotic pathways, promoting neuronal survival. TUDCA:

  • Improves protein folding capacity through its chaperoning activity, in turn reducing protein aggregation and deposition;
  • Reduces reactive oxygen species production, leading to protection against mitochondrial dysfunction;
  • Ameliorates endoplasmic reticulum stress; and
  • Inhibits expression of pro-inflammatory cytokines, exerting an anti-neuroinflammatory effect.

Although Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, amyotrophic lateral sclerosis (ALS), and cerebral ischemia have different disease progressions, they share similar pathways which can be targeted by TUDCA. This makes this bile acid a potentially strong therapeutic option to be tested in human diseases. Clinical evidence collected so far has reported comprehensive data on ALS only.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9166453/ “Tauroursodeoxycholic acid: a potential therapeutic tool in neurodegenerative diseases”

The misnomer of nonessential amino acids

Three papers, starting with a 2022 review:

“Ideal diets must provide all physiologically and nutritionally essential amino acids (AAs).

Proposed optimal ratios and amounts of true digestible AAs in diets during different phases of growth and production. Because dynamic requirements of animals for dietary AAs are influenced by a plethora of factors, data below as well as the literature serve only as references to guide feeding practices and nutritional research.

10.1177_15353702221082658-table5

Nutritionists should move beyond the ‘ideal protein’ concept to consider optimum ratios and amounts of all proteinogenic AAs in diets for mammals, birds, and aquatic animals, and, in the case of carnivores, also taurine. This will help formulate effectively low-protein diets for livestock (including swine and high-producing dairy cattle), poultry, fish, and crustaceans, as well as zoo and companion animals.”

https://journals.sagepub.com/doi/10.1177/15353702221082658 “The ‘ideal protein’ concept is not ideal in animal nutrition”


A second 2022 review focused on serine:

“The main dietary source of L-serine is protein, in which L-serine content ranges between 2 and 5%. At the daily intake of ~1 g protein per kg of body weight, the amount of serine obtained from food ranges between 1.4 and 3.5 g (13.2–33.0 mmol) per day in an adult.

Mechanisms of potential benefits of supplementing L-serine include increased synthesis of sphingolipids, decreased synthesis of 1-deoxysphingolipids, decrease in homocysteine levels, and increased synthesis of cysteine and its metabolites, including glutathione. L-serine supplementation has been suggested as a rational therapeutic approach in several disorders, particularly primary disorders of L-serine synthesis, neurodegenerative disorders, and diabetic neuropathy.

Unfortunately, the number of clinical studies evaluating dietary supplementation of L-serine as a possible therapy is small. Studies examining therapeutic effects of L-serine in CNS injury and chronic renal diseases, in which it is supposed that L-serine weakens glutamate neurotoxicity and lowers homocysteine levels, respectively, are missing.”

https://www.mdpi.com/2072-6643/14/9/1987/htm “Serine Metabolism in Health and Disease and as a Conditionally Essential Amino Acid”


A 2021 review subject was D-serine, L-serine’s D-isoform:

“The N-methyl-D-aspartate glutamate receptor (NMDAR) and its co-agonist D-serine are currently of great interest as potential important contributors to cognitive function in normal aging and dementia. D-serine is necessary for activation of NMDAR and in maintenance of long-term potentiation, and is involved in brain development, neuronal connectivity, synaptic plasticity, and regulation of learning and memory.

The source of D-amino acids in mammals was historically attributed to diet or intestinal bacteria until racemization of L-serine by serine racemase was identified as the endogenous source of D-serine. The enzyme responsible for catabolism (breakdown) of D-serine is D-amino acid oxidase; this enzyme is most abundant in cerebellum and brainstem, areas with low levels of D-serine.

Activation of the NMDAR co-agonist-binding site by D-serine and glycine is mandatory for induction of synaptic plasticity. D-serine acts primarily at synaptic NMDARs whereas glycine acts primarily at extrasynaptic NMDARs.

In normal aging there is decreased expression of serine racemase and decreased levels of D-serine and down-regulation of NMDARs, resulting in impaired synaptic plasticity and deficits in learning and memory. In contrast, in AD there appears to be activation of serine racemase, increased levels of D-serine and overstimulation of NMDARs, resulting in cytotoxicity, synaptic deficits, and dementia.”

https://www.frontiersin.org/articles/10.3389/fpsyt.2021.754032/full “An Overview of the Involvement of D-Serine in Cognitive Impairment in Normal Aging and Dementia”


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Take β-glucan for new blood vessels

This 2022 cell study investigated yeast cell wall β-glucan’s effects on angiogenesis:

“Angiogenesis, the formation of new blood vessels, is essential for embryonic development and physiological damage repair, such as wound healing and post-ischemic tissue restoration. It is also essential for pathological processes, such as diabetic retinopathy, rheumatoid arthritis, and atherosclerosis.

We evaluated physical and functional interactions of β-glucan with HDAC5, including the scratched wound, tube formation, and rat aortic ring assays. β-glucan-induced HDAC5 pathway mediates cell migration and formation of tubes and microvessels in vitro and ex vivo.

β-glucan angiogenesis

Our findings demonstrate that β-glucan-induced HDAC5 phosphorylation is important in endothelial cell angiogenesis. Further investigations into how β-glucan phosphorylates HDAC5 are required. There is also a need to identify a receptor that specifically binds to β-glucan in vascular endothelial cells.

β-glucan could be useful in developing new strategies in therapeutic angiogenesis for conditions such as cardiovascular disease and diabetes.”

https://www.sciencedirect.com/science/article/abs/pii/S0141813022010273 “Yeast beta-glucan mediates histone deacetylase 5-induced angiogenesis in vascular endothelial cells” (not freely available). Thanks to Dr. Chan-Gi Pack for providing a copy.


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Thyroid function

This 2022 review subject was thyroid function changes:

“Circulating concentrations of thyrotropin (TSH) and thyroxine (T4) are tightly regulated. Each individual has setpoints for TSH and free T4 which are genetically determined, and subject to environmental and epigenetic influence.

What is normal for one individual may not be normal for another, even within conventional definitions of euthyroidism. Notably, circulating TSH exists in several different isoforms with varying degrees of glycosylation, sialylation, and sulfonation which affect tissue availability and bioactivity. This is not reflected in immunoreactive TSH concentrations determined by routine laboratory assays.

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TSH and free T4 relationship analyzed by age in 120,403 patients who were not taking thyroxine treatment. Median TSH for each free T4 integer value (in pmol/ L) was calculated, then plotted as 20-year age bands in adults. Dotted horizontal and vertical lines mark the TSH reference range (0.4 to 4.0 mU/L) and free T4 reference range (10 to 20 pmol/L), respectively.

Mild TSH elevation in older people does not predict adverse health outcomes. In fact, higher TSH is associated with greater life expectancy, including extreme longevity.

In older people, TSH increases with aging without an accompanying fall in free T4. Clinical guidelines now recommend against routine levothyroxine treatment in older people with mild subclinical hypothyroidism.”

https://e-enm.org/journal/view.php?doi=10.3803/EnM.2022.1463 “Thyroid Function across the Lifespan: Do Age-Related Changes Matter?”


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Epigenetic clocks and entropy

Two epigenetic clock papers, starting with a 2022 rodent study:

“We tested performance of new pan-tissue and liver-specific epigenetic mouse clocks, evaluating how these related to metabolic states, genotype-dependent life expectancy, and methylome entropy.

Entropy, a measure of noise and information loss, increases as a function of time and age. In context of the methylome, higher entropy represents a tendency for the highly organized hypo- and hypermethylated landscape to erode towards a more hemi-methylated [discordant] state.

This increase in disorder, particularly across CpGs that are highly conserved, could have important functional consequences. Entropy of age-gain CpGs was increased by high fat diet, and predicted strain lifespan.

Overall, we find that mice belonging to longer-lived BXD strains had a more youthful methylome with lower entropy at age-gain CpGs. Entropy of age-loss CpGs on the other hand, was related to body weight.

entropy associations

(h) Residual plot (adjusted for age, diet, BWF [final body weight], glucose, cholesterol, and batch) shows an inverse association between entropy at age-gain sites, and lifespan. (i) A similar residual plot shows the association between BWF and age-loss entropy.

The rate of noise accumulation, an aspect of epigenomic aging, can vary between individuals. Resilience or susceptibility to higher noise may be partly modulated by diet as well as genetic factors.

Convergence of evidence from genetic and gene expression analyses indicates that genes involved in metabolism and energy balance contribute to age-dependent restructuring of the methylome, which in turn forms the basis of epigenetic clocks.”

https://elifesciences.org/articles/75244 “Genetic loci and metabolic states associated with murine epigenetic aging”


Reference 28 was a 2021 human study cited for “identified the APOE locus as the strongest GWAS hit for two measures of biological age acceleration”

“We observed inverse APOE e2 and e4 associations and unique pathway enrichments when comparing two biological age measures. Genes associated with BioAgeAccel were enriched in lipid related pathways, while genes associated with PhenoAgeAccel showed enrichment for immune system, cell function, and carbohydrate homeostasis pathways, suggesting the two measures capture different aging domains.

Our study reaffirms that aging patterns are heterogeneous across individuals, and the manner in which a person ages may be partly attributed to genetic predisposition. Understanding personalized aging susceptibility phenotypes has important implications for primary and secondary disease interventions.”

https://onlinelibrary.wiley.com/doi/10.1111/acel.13376 “Genetic associations for two biological age measures point to distinct aging phenotypes”


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Vascular memory

This 2022 rodent study investigated effects of inducing hypertension for two weeks:

“Hypertension is conventionally associated with a neurohormonal activation from the sympathetic nervous and the renin-angiotensin-aldosterone systems. Angiotensin II (AngII) is a potent regulator of blood pressure, and is also a key player in hypertension development.

An initial 2-week exposure to AngII induced profound changes in cardiac and vascular remodeling, including endothelial activation, vascular inflammation and oxidant stress, all of which were maintained up to 3 weeks after AngII withdrawal. This phenotype was sustained despite early normalization of blood pressure after AngII withdrawal.

Our RNAseq pathway analysis suggests involvement of epigenetic regulators involved in methylation, such as PRC2. PCR2 complex catalyzes trimethylation of histone H3 on lysine 27 (H3K27me3), a histone mark necessary for maintaining transcriptional repression during multicellular development.

H3K27me3 AngII

Cell type-specific patterns of H3K27me3 are crucial for preserving cell identity. Consistent with this analysis, we observed a significant increase in H3K27me3 epigenetic mark in aortic tissue, intriguingly, only in both memory conditions.

Transient exposure to Ang II produces prolonged vascular remodeling with robust ACTA2 downregulation, associated with epigenetic imprinting, supporting a memory effect despite stimulus withdrawal. Future characterization of underlying AngII-dependent signaling might unveil new targets for its therapeutic modulation and reversal of this adverse legacy effect.”

https://www.frontiersin.org/articles/10.3389/fcvm.2022.854361/full “Sustained Downregulation of Vascular Smooth Muscle Acta2 After Transient Angiotensin II Infusion: A New Model of Vascular Memory”


These subjects’ ages were equivalent to a 20-year-old human:

  • How much earlier could our vascular system retain events we experienced such as epigenetic H3K27me3 increases? Teenaged, late childhood, early childhood, infancy, fetal parts of our lives?
  • How long would these vascular system memories and their continued signaling linger?
  • What experiences could change these long-lasting memories?

Icy fire

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Kickstarting endogenous regenerative pathways

A 2022 amphibian study by the Electroceuticals team investigated limb regeneration:

“Organisms such as Xenopus laevis – whose limited regenerative capacities in adulthood mirror those of humans – are important models with which to test interventions that can restore form and function. We demonstrate long-term (18 months) regrowth, marked tissue repatterning, and functional restoration of an amputated X. laevis hindlimb following a 24-hour exposure to a multidrug, pro-regenerative treatment delivered by a wearable bioreactor.

  • Regenerated multidrug treatment (MDT) hindlimbs were longer than the no added factors (BD) and no device (ND) groups by 2.5 mpa, as indicated by growth beyond resection site (red dashed line).
  • At 4 mpa, vascularized structures developed at the distal extension of MDT (yellow arrow), but not BD or ND regenerates.
  • At 9 mpa, digit-like projections appeared (blue arrow), contrasting hypomorphic spikes of BD and ND regenerates (pink arrows).

limb regeneration

We suggest that the overall strategy of providing wound cells with an aqueous, amniotic-like environment, which is uniquely given through our bioreactor, that contains pro-regenerative signals is likely to be an effective method for kickstarting biomedically relevant growth and patterning cascades that are too complex to directly implement. One additional direction that may present new opportunities for enhanced regeneration is to assess immune function in relation to tissue remodeling.”

https://www.science.org/doi/10.1126/sciadv.abj2164 “Acute multidrug delivery via a wearable bioreactor facilitates long-term limb regeneration and functional recovery in adult Xenopus laevis”

Intergenerational epigenetic inheritance of trained immunity, Part 2

A 2022 McGill University rodent study couldn’t replicate Part 1 findings:

“We find that using similar mouse models of trained immunity induced by:

  1. Live vaccination (BCG);
  2. PAMPs (β-glucan); or
  3. Infection (C. albicans),

protection against:

  1. Viral (influenza virus);
  2. Bacterial (Mycobacterium tuberculosis (Mtb)); or
  3. Fungal (C. albicans)

infections was the same between offspring of trained and non-trained parents.

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BCG vaccination in the offspring of vaccinated parents does not enhance trained immunity in macrophages.

a) Mice were vaccinated with BCG-iv (1 × 10⁶ CFU) for one month and mated with vaccinated or naive counterparts. 6–8 week-old F1.1 and F1.3 offspring were then vaccinated or not with BCG-iv (1 × 10⁶ CFU).

b), c) At 1 month post BCG vaccination, protective capacities of BMDM from BCG-iv vaccinated and nonvaccinated F1.1 (b), or F1.3 (c) offspring from naïve or BCG-iv vaccinated parents were assessed against M. tuberculosis (H37Rv, MOI 1) infection. * p < 0.05.”

https://www.nature.com/articles/s41590-021-01102-0 “Lack of evidence for intergenerational inheritance of immune resistance to infections” (not freely available)


Part 1 coauthors replied:

“We are very encouraged that this topic is gaining increased interest. The reason for the discrepancy between findings in the two studies is unclear. It likely involves local differences in mouse substrains, housing, diet, microbiome, infection models, or other factors.

These findings underscore the effect of environment on intergenerational inheritance of infection resistance. What these environmental factors are and how these factors are integrated with regards to intergenerational inheritance remains largely elusive at this time.

One intriguing possibility that needs to be tested in future studies is whether such effects may be more robust in outbred wild mice, in which subtle environmental changes may have less strong impact.”

https://www.nature.com/articles/s41590-021-01103-z “Reply to: ‘Lack of evidence for intergenerational inheritance of immune resistance to infections'”


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Lifespan Uber Correlation

This 2022 study developed new epigenetic clocks:

“Maximum lifespan is deemed to be a stable trait in species. The rate of biological function decline (i.e., aging) would be expected to correlate inversely with maximum species lifespan. Although aging and maximum lifespan are intimately intertwined, they nevertheless appear in some investigations to be distinct processes.

Some cytosines conserved across mammals exhibit age-related methylation changes so consistent that they were used to successfully develop cross-species age predictors. In a similar vein, methylation levels of some conserved cytosines correlate highly with species lifespan, leading to the development of highly accurate lifespan predictors. Surprisingly, little to no commonality is found between these two sets of cytosines.

We correlated the intra-species age correlation with maximum lifespan across mammalian species. We refer to this correlation of correlations as Lifespan Uber Correlation (LUC).

We overlapped genes from the LUC signature with genes found in human genome-wide association studies (GWAS) of various pathologies and conditions. With all due caution, we report that some genes from the LUC signature were those highlighted by GWAS to be associated with type II diabetes, stroke, chronic kidney disease, and breast cancer.

Human aging genes vs mammalian LUC

We used the subset of CpGs found to be significant in our LUC to build age estimators (epigenetic clocks). We demonstrated that these clocks are able to capture effects of interventions that are known to alter age as well as lifespan, such as caloric restriction, growth hormone receptor knockout, and high-fat diet.

We found that Bcl11b heterozygous knockout mice exhibited an increased epigenetic age in the striatum. BCL11B is a zinc finger protein with a wide range of functions, including development of the brain, immune system, and cardiac system.

This gene is also implicated in several human diseases including, but not limited to, Huntington disease, Alzheimer’s diseases, HIV, and T-cell malignancies. BCL11B plays an important role in adult neurogenesis, but is less studied in the context of lifespan disparities in mammals.

Bcl11b knockout affected both DNA methylation and mRNA expression of LUC genes. Our current study does not inform us about the potential role of Bcl11b in aging processes during adulthood since observed patterns could be attributed to developmental defects.

We are characterizing other genetic and non-genetic interventions that perturb the LUC clocks. These we will feature in a separate report that will uncover biological processes regulated by LUC cytosines and their associated genes.”

https://www.biorxiv.org/content/10.1101/2022.01.16.476530v1 “Divergent age-related methylation patterns in long and short-lived mammals”


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Sulforaphane vs. too much oxygen

This 2021 rodent study investigated perinatal effects of hyperoxia and sulforaphane:

“We demonstrated that early-life oxidant-induced acute lung injury had significant consequences later in life on NRF2-dependent respiratory syncytial virus (RSV) susceptibility in mice. We also determined that increased antioxidant conditions in utero potentially contribute to a decreased risk of postnatal airway disease as we found that prenatal antioxidant sulforaphane (SFN) protected developing lungs from bronchopulmonary dysplasia (BPD)-like oxidative pathogenesis in mice.

Unexpectedly, our results indicated that prenatal SFN-mediated postnatal protection against BPD-like phenotypes are not NRF2-dependent. Prenatal SFN markedly improved hyperoxia-caused severe BPD-like lung injury parameters in Nrf2−/− pups while we observed relatively marginal protection by in utero SFN in hyperoxia-resistant Nrf2+/+ pups.

SFN is a strong NRF2 and ARE gene inducer for cytoprotection by NRF2 stabilization. However, SFN also acts through other mechanisms, including NF-κB inhibition, MAPK activation, and histone deacetylase inhibition for anti-inflammation, chemoprevention, apoptosis, and autophagy.

Our study provided new insights into infant oxidant lung injury severity influence on persistence of pulmonary morbidity and therapeutic intervention for NRF2 agonists. Our results also provided justification for further studies on feto–placental barrier crossing of SFN metabolites and SFN-triggered molecular and epigenetic aspects of maternal cues for barrier and fetal lung signaling.”

https://www.mdpi.com/2076-3921/10/12/1874/htm “Murine Neonatal Oxidant Lung Injury: NRF2-Dependent Predisposition to Adulthood Respiratory Viral Infection and Protection by Maternal Antioxidant”


This study’s oral human-equivalent dose for treatment dams was 9 mg sulforaphane (1.67 mg x .081 x 70 kg) every other day during the last half of pregnancy. A small dose per How much sulforaphane is suitable for healthy people?

“The daily SFN dose found to achieve beneficial outcomes in most of the available clinical trials is around 20-40 mg.”

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Inevitable individual differences

This 2021 review subject was individual differences:

“We will focus on recent findings that try to shed light on the emergence of individuality, with a particular interest in Drosophila melanogaster.

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Another possible source of potential behavioral variability might come from the interaction of individuals with environmental microbes, from Wolbachia infections to changes in the gut microbiome. In this particular case, no genetic variation or neural circuit alteration would be responsible for the change in behavior.

Finally, from an evolutionary point of view, individuality might play an essential role in providing an adaptive advantage. For example, we have described that animals might use diversified bet-hedging as a mechanism to produce high levels of variation within a population to ensure that at least some individuals will be well-adapted when facing unpredictable environments.”

https://www.frontiersin.org/articles/10.3389/fphys.2021.719038/full “Behavior Individuality: A Focus on Drosophila melanogaster


Other papers on this subject include:

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Offspring brain effects from maternal adversity

This 2021 rodent study investigated conception through weaning effects on offspring from stressing their mothers:

“We investigated consequences of two prenatal insults, prenatal alcohol exposure (PAE) and food-related stress, on DNA methylation profiles of the rat brain during early development. We analyzed patterns in prefrontal cortex, a key brain region involved in cognition, executive function, and behavior, of both males and females, and found sex-dependent and sex-concordant influences of these insults.

The pair-fed (PF) group in the PAE model is a standard control for effects of alcohol in reducing food intake. However, compared to the PAE group that, albeit eating less, eats ad libitum, pair-feeding is a treatment in itself, with PF dams receiving a restricted ration, which results in both hunger and a disrupted feeding schedule. These stress-related effects could potentially parallel or model food scarcity or food insecurity in human populations.

We observed more DMRs (Differentially Methylated Regions) that showed decreased DNAm rather than increased DNAm in PF animals, suggesting that food-related stress may interfere with one-carbon metabolism and the pathways that deposit methylation on DNA. We also identified a sex-concordant DMR that showed decreased DNAm in PF animals in the glucocorticoid receptor Nr3c1, which plays a key role in stress responsivity and may reflect a reprogramming of the stress response.

This result is in line with previous studies that have shown that pair-feeding is a considerable stressor on dams, with lasting consequences on development, behavior, and physiology of their offspring. Altered DNAm of this key HPA axis gene may reflect broader alterations to stress response systems, which may in turn, influence programming of numerous physiological systems linked to the stress response, including immune function, metabolic processes, and circadian rhythms.

In PAE and PF animals compared to controls, we identified 26 biological pathways that were enriched in females, including those involved in cellular stress and metabolism, and 10 biological pathways enriched in males, which were mainly involved in metabolic processes. These findings suggest that PAE and restricted feeding, both of which act in many respects as prenatal stressors, may influence some common biological pathways, which may explain some of the occasional overlap between their resulting phenotypes.

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This study highlights the complex network of neurobiological pathways that respond to prenatal adversity/stressors and that modulate differential effects of early life insults on functional and health outcomes. Study of these exposures provides a unique opportunity to investigate sex-specific effects of prenatal adversity on epigenetic patterns, as possible biological mechanisms underlying sex-specific responses to prenatal insults are understudied and remain largely unknown.”

https://www.mdpi.com/2073-4425/12/11/1773/htm “Prenatal Adversity Alters the Epigenetic Profile of the Prefrontal Cortex: Sexually Dimorphic Effects of Prenatal Alcohol Exposure and Food-Related Stress”


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The impact of transgenerational epigenetic inheritance and early life experiences

A 2021 interview with McGill University’s Moshe Szyf:

There is a rejection of transgenerational inheritance as it goes against progressive thinking because it ties us to previous generations. The theory faces rejection because it sounds deterministic.

But if you understand what epigenetics is, it’s not deterministic. There is stability, and there’s also room for dynamic change.

The only way things change in the body for the long term is via epigenetics. We don’t know everything yet, new discoveries are yet to happen, and then we will just say, ‘Wow, it’s so obvious!’

The immune system is tightly connected to the brain and is directly affected by early adversity. Even though we will not be able to learn what’s going on in the brain, as far as epigenetics in living people, we will gain a lot of information from how the immune system responds to early adversity, and how this is correlated with behavioral phenotype and with mental health.

This brings into question the whole field of neuroimmunology, of which there is a lot of data. But it seems that a lot of psychiatrists are totally oblivious to these data, which is astounding, because the glucocorticoid hormone – the major player in this mechanism due to its involvement in early life stress as well as control of behavior – also controls immune function.

Nobody can live long enough to oversee a human transgenerational study. In humans, correlations are usually in peripheral tissue, where changes are small. The jury’s not out yet, but if evolution used it for so many different organisms, some of which are very close to us in the evolutionary ladder, it’s impossible that humans don’t use it.

How are current findings in animal models relevant to humans? How do we develop human paradigms that will allow us to achieve a higher level of evidence than what we have now?

  • One way is the immune-inflammatory connection to other diseases. I think this is where the secret of epigenetic aging lies, as well as epigenetics of other diseases.
  • Every disease is connected to the immune system. The brain translates the behavioral environment to the immune system, and then the immune system sends chemical signals across the body to respond to these challenges.

We need to understand that epigenetic programs are a network. Move beyond candidate genes, understand the concept of a network, and really understand the challenge: Reset the epigenetic network.

Epigenetics is going to be rapidly translated to better predictors, better therapeutics, and more interesting therapeutics. Not necessarily the traditional drug modeled against a crystal structure of an enzyme, but a more networked approach. Ideas about early life stress are critical and have impacted the field of childcare by highlighting the importance of early childhood relationships.”

https://www.futuremedicine.com/doi/10.2217/epi-2021-0483 “The epigenetics of early life adversity and trauma inheritance: an interview with Moshe Szyf”


Week 87 of Changing to a youthful phenotype with sprouts

This week I dialed back eating microwaved 3-day-old broccoli / red cabbage / mustard sprouts from twice a day to once a day. For my reasoning, here are two papers on broccoli sprouts and thyroid function, with the first a 2018 human study:

“We analyzed biochemical measures of thyroid function and thyroid autoimmunity in a subset of participants in a broccoli sprout clinical trial. The present work is a retrospective analysis of a subset of serum samples collected during a clinical trial conducted from mid-October 2011 to early January 2012.

130 individuals received placebo beverage, and 137 received broccoli sprout beverage for 84 consecutive days (12 weeks). Blood samples from day 0 and day 84 were analyzed in a subset of 45 female participants (19 placebo, 26 broccoli sprout beverage) for serum thyroid-stimulating hormone (TSH), free thyroxine (fT4), thyroglobulin (TG), anti-TG, and anti-thyroid peroxidase (anti-TPO) antibodies.

The percentage of patients with subclinical hypothyroidism (elevated TSH with normal fT4) was not significantly different between the two groups either before or after treatment.

subclinical hypothyroidism

Daily ingestion of a broccoli sprout extract beverage over 84 days had no deleterious effect on thyroid function tests or measures of thyroid autoimmunity. It may be prudent to evaluate thyroidal safety of plant-based food supplements on a case-by-case basis.”

https://www.sciencedirect.com/science/article/abs/pii/S0278691519300547 “Broccoli sprout beverage is safe for thyroid hormonal and autoimmune status: Results of a 12-week randomized trial” (not freely available)


A 2020 review by three of these coauthors summarized further details:

“One difference between the thyroid and other tissues is that ROS are not primarily a byproduct of its physiology, but an indispensable part of it. Thyroid follicular cells actively produce H2O2 to facilitate a cascade of redox reactions that sequentially oxidize iodide, iodinate tyrosine residues within Tg, and couple iodinated tyrosine residues of Tg to each other to form T4 and T3 (triiodothyronine).

There exists a fail-safe mechanism in which specific combinations of four Keap1 cysteines can form a disulfide bond to sense H2O2. This sensing mechanism appears to be distinct from that triggered by other Nrf2 inducers, such as electrophiles.

Findings from Keap1KD mice suggest that chronic genetic activation of Nrf2 signaling may have negative consequences for the thyroid gland. However, analysis of data from a clinical trial has shown that consumption of a broccoli sprout beverage (yielding pharmacologically active amounts of the Nrf2-activating compound sulforaphane) is safe for thyroid hormonal and autoimmune status during a 12-week administration period.

Nevertheless, it appears prudent to monitor thyroid function and thyroid volume (at least by palpation) in patients treated with Nrf2-modulating compounds in clinical trials or clinical practice.”

https://www.mdpi.com/2076-3921/9/11/1082/htm “The Keap1/Nrf2 Signaling Pathway in the Thyroid—2020 Update”


My Day 70 lab results for inflammation markers were great:

IL-6 2020

A year later, IL-6 was below the test’s detection limit, and high-sensitivity C-reactive protein could hardly have been better at 0.24 mg/L.

But TSH (reference interval 0.45 – 4.50 μIU/mL) increased from 3.01 to 7.50. Here’s what Labcorp Technical Review L8186 said:

“The panel concluded that despite the fact that serum TSH concentrations higher than 2.5 μIU/mL but less than 4.5 μIU/mL may identify some individuals with the earliest stage of hypothyroidism, there is no evidence for associated adverse consequences. Additionally, consequences of subclinical hypothyroidism with serum TSH levels between 4.5 μIU/mL and 10 μIU/mL are minimal, and the panel recommends against routine treatment of patients with TSH levels in these ranges.”

I went in last weekend to retest. Although the provider verbally agreed to test TSH, free T3, and free T4, a different test was ordered.

TSH was still high at 5.85 μIU/mL. Other measurements (Total T4, T3 Uptake, and Free Thyroxine Index) aren’t suitable substitutes for free T3 and free T4. I’ll specify Labcorp test numbers next time.


My hypothesis is that preconditioning my endogenous ARE system twice daily worked alright elsewhere, but not for my thyroid. We’ll find out in 2022 whether halving the electrophilic activations of my Nrf2 signaling pathway has any effect on thyroid measurements.

I don’t take anything with, or an hour before or after these very reactive isothiocyanates. I continue to eat 3-day-old oat sprouts twice a day with other foods.

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Is liver damage reversible?

This 2021 rodent study measured sequential liver changes caused by a high-fat diet:

“Using a longitudinal mouse study of diet-induced obesity in male mice, we investigated kinetics of hepatic DNA methylation and gene expression compared to those of obesity-induction to assess if they could be causal for development of insulin resistance. We aimed to find out if these changes were reversed by massive weight loss induced by vertical sleeve gastrectomy or metformin treatment.

We identified two CpG sites within exon 1 of Fgf21 that became gradually hypomethylated upon HFD feeding. DNA demethylation started between week two and four, to become significant at week five, and significantly correlated with hepatic Fgf21 gene expression.

These DNA methylation changes preceded development of insulin resistance, and were potentially causally involved in increased Fgf21 expression and plasma levels associated with insulin resistance. This points to a key regulatory function of gene body DNA methylation, which was eventually a compensatory response to counteract the developing insulin resistance.

HFD-induced decrease in Fgf21 DNA methylation could not be reversed by vertical sleeve gastrectomy or metformin treatment. As soon as weight loss slowed down or mice started to re-gain weight, differences in DNA methylation were no longer detected compared to sham-operated mice.

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As the altered DNA methylation pattern was acquired during adulthood in differentiated cells, our data emphasize that metabolic programming via DNA methylation is dynamic and not restricted to fetal development. This supports the concept that individuals can actively influence their DNA methylation patterns by lifestyle choices.

Our data indicate that DNA methylation alterations in key metabolic tissues can be acquired by an obesogenic diet, and not easily be reversed by interventions common in obese and diabetic subjects.”

https://www.sciencedirect.com/science/article/pii/S0955286321003272 “Dietary induction and reversal of obesity and insulin resistance is associated with changes in Fgf21 DNA methylation in liver of mice”


This study attempted two interventions that didn’t have desired effects. All about the betaine mentioned others that may reverse liver epigenetic changes.

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