Gut microbiota and aging

This 2020 review explored the title subject:

“The human body contains 1013 human cells and 1014 commensal microbiota. Gut microbiota play vital roles in human development, physiology, immunity, and nutrition.

Human lifespan was thought to be determined by the combined influence of genetic, epigenetic, and environmental factors including lifestyle-associated factors such as exercise or diet. The role of symbiotic microorganisms has been ignored.

Age-associated alterations in composition, diversity, and functional features of gut microbiota are closely correlated with an age-related decline in immune system functioning (immunosenescence) and low-grade chronic inflammation (inflammaging). Immunosenescence and inflammaging do not have a unidirectional relationship. They exist in a mutually maintained state where immunosenescence is induced by inflammaging and vice versa.

Immunosenescence changes result in both quantitative and qualitative modifications of specific cellular subpopulations such as T cells, macrophages and natural killer cells as opposed to a global deterioration of the immune system. Neutrophils and macrophages from aged hosts are less active with diminished phagocytosing capability.

Gut microbiota transform environmental signals and dietary molecules into signaling metabolites to communicate with different organs and tissues in the host, mediating inflammation. Gut microbiota modulations via dietary or probiotics are useful anti-inflammaging and immunosenescence interventions.

The presence of microbiomic clocks in the human body makes noninvasive, accurate lifespan prediction possible. Prior to occurrence of aging-related diseases [shown above], bidirectional interactions between the gut and extraenteric tissue will change.

Correction of accelerated aging-associated gut dysbiosis is beneficial, suggesting a link between aging and gut microbiota that provides a rationale for microbiota-targeted interventions against age-related diseases. However, it is still unclear whether gut microbiota alterations are the cause or consequence of aging, and when and how to modulate gut microbiota to have anti-aging effects remain to be determined.”

https://www.tandfonline.com/doi/abs/10.1080/10408398.2020.1867054 “Gut microbiota and aging” (not freely available; thanks to Dr. Zongxin Ling for providing a copy)


1. The “Stable phase” predecessor to this review’s subject deserved its own paper:

“After initial exposure and critical transitional windows within 3 years after birth, it is generally agreed that human gut microbiota develops into the typical adult structure and composition that is relatively stable in adults.

gut microbiota by age phenotype

However, the Human Microbiome Project revealed that various factors such as food modernization, vaccines, antibiotics, and taking extreme hygiene measures will reduce human exposure to microbial symbionts and led to shrinkage of the core microbiome, while the reduction in microbiome biodiversity can compromise the human immune system and predispose individuals to several modern diseases.”

2. I looked for the ten germ-free references in the “How germ-free animals help elucidate the mechanisms” section of The gut microbiome: its role in brain health in this review, but didn’t find them cited. Likewise, the five germ-free references in this review weren’t cited in that paper. Good to see a variety of relevant research.

There were a few overlapping research groups with this review’s “Gut-brain axis aging” section, although it covered only AD and PD research.

3. Inflammaging is well-documented, but is chronic inflammation a condition of chronological age?

A twenty-something today who ate highly-processed food all their life could have gut microbiota roughly equivalent to their great-great grandparents’ at advanced ages. Except their ancestors’ conditions may have been byproducts of “an unintended consequence of both developmental programmes and maintenance programmes.

Would gut microbiota be a measure of such a twenty-something’s biological age? Do we wait until they’re 60, and explain their conditions by demographics? What could they do to reset themself back to a chronological-age-appropriate phenotype?


The future of your brain is in your gut right now

A 2020 paper by the author of Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease:

“The gut and brain communicate bidirectionally via several pathways which include:

  1. Neural via the vagus nerve;
  2. Endocrine via the HPA axis;
  3. Neurotransmitters, some of which are synthesized by microbes;
  4. Immune via cytokines; and
  5. Metabolic via microbially generated short-chain fatty acids.

How does nature maintain the gut-microbiome-brain axis? Mechanisms to maintain homeostasis of intestinal epithelial cells and their underlying cells are a key consideration.

The symbiotic relationship that exists between microbiota and the human host is evident when considering nutrient requirements of each. The host provides food for microbes, which consume that food to produce metabolites necessary for health of the host.

Consider function of the human nervous system, not in isolation but in integration with the gastrointestinal ecosystem of the host, in expectation of a favorable impact on human health and behavior.”

https://www.sciencedirect.com/science/article/pii/B9780128205938000148 “Chapter 14 – The gut microbiome: its role in brain health” (not freely available)


Always more questions:

  • What did you put into your gut today?
  • What type of internal environment did it support?
  • What “favorable impact on human health and behavior” do you expect from today’s intake?
  • How will you feel?
  • Will you let evidence guide feeding your gut environment?

See Switch on your Nrf2 signaling pathway for an interview with the author.

Week 37 of Changing to a youthful phenotype with broccoli sprouts

1. Been wrong about a few things this past week:

A. I thought in Week 28 that extrapolating A rejuvenation therapy and sulforaphane results to humans would produce personal results by this week. An 8-day rat treatment period ≈ 258 human days, and 258 / 7 ≈ 37 weeks.

There are just too many unknowns to say why that didn’t happen. So I’ll patiently continue eating a clinically relevant 65.5 gram dose of microwaved broccoli sprouts twice every day.

PXL_20201015_105645362

The study’s lead researcher answered:

“Depends, it might take 37 weeks or more for some aspects of ‘youthening’ to become obvious. It might even take years for others.

Who really cares if you are growing younger every day?

For change at the epigenomic/cellular level to travel up the biological hierarchy from cells to organ systems seems to take time. But the process can be repeated indefinitely (so far as we know) so by the second rejuvenation you’re already starting at ‘young’. (That would be every eight to ten years I believe.)”

His framework is in An environmental signaling paradigm of aging.

B. I thought that adding 2% mustard seed powder to microwaved broccoli sprouts per Does sulforaphane reach the colon? would work. Maybe it would, maybe it wouldn’t, but my stomach and gut said that wasn’t for me.

C. I thought I could easily add Sprouting whole oats to my routine. I ran another trial Sprouting hulled oats using oat seeds from a different company and Degree of oat sprouting as a model.

2. Oat sprouts analysis paired studies were very informative, don’t you think? One study produced evidence over a range of germination parameters (hulled / dehulled seeds of two varieties, for 1-to-9 days, at 12-to-20°C). And evaluated what mix of germination parameters would simultaneously maximize four parameters (β-glucan, free phenolic compounds, protease activity and antioxidant capacity) while minimizing two (enzymes α-amylase and lipase). Then a follow-up study characterized oat seeds sprouted under these optimal conditions.

I doubted PubMed’s “oat sprout” 20 search results for research 1977 to the present. Don’t know why they didn’t pick up both of these 2020 studies, but I’m sure that .gov obvious hindrances to obtaining relevant information like this won’t be fixed. What other search terms won’t return adequate results?

3. The blog post readers viewed this week that I made even better was Do delusions have therapeutic value? from May 2019. Sometimes I’ve done good posts describing why papers are poorly researched.

4. I’ve often changed my Week 4 recipe for an AGE-less Chicken Vegetable Soup dinner (half) then the next day for lunch. The biggest change brought about by 33 weeks of behavioral contagion is that I now care more about whether vegetables are available than whether or not they’re organic. Coincidentally, I’ve developed a Costco addiction that may require intervention.

  • 1 lemon
  • 3 Roma tomatoes
  • 4 large carrots
  • 6 stalks organic celery
  • 6 mushrooms
  • 6 cloves garlic
  • 6 oz. organic chicken breast fillet
  • 1 cup organic pasta
  • 1 yellow squash, alternated with 1 zucchini
  • 1 cup sauvignon blanc
  • 32 oz. “unsalted” chicken broth, which still contains 24% of the sodium RDA

Pour wine into a 6-quart Instant Pot; cut and strain squeezed lemon; cut chicken into 1/4″ cubes and add; start mixture on Sauté. Wash and cut celery; wash and scrub carrots; stir pot at 4 minutes; stir in celery at 5 minutes.

Cut and stir in carrots. Wash mushrooms, slicing only if supersized. When pot boils around 10 minutes, add chicken broth and stir.

Wash and slice yellow squash / zucchini; crush and peel garlic but don’t slice. When pot boils again around 15 minutes, stir in pasta; turn off pot.

Add yellow squash / zucchini, mushrooms, garlic; wash and add whole tomatoes. Let set for 20 minutes; stir bottom-to-top 5 and 15 minutes after turning off, and again before serving.

AGE-less Chicken Vegetable Soup is tasty enough to not need seasoning, at least when freshly prepared.

Sprouting oats

Three 2020 studies investigated properties of sprouted oats. This first study compared one oat cultivar’s seed and sprout contents for phenolic compounds, and evaluated oat sprouts’ protection against developing colon cancer:

“The purpose of this investigation was to evaluate whether sprouted oats (SO) of the Turquesa variety still possessed effective physiologically bioactive compounds, i.e., phenolics, flavonoids, AVAs [avenanthramides], and phytosterols, and whether it exerted antioxidant and anti-inflammatory effects, as well as the capacity to improve relevant intestinal parameters, in an AOM [azoxymethane] / DSS [dextran sulfate sodium]-induced CRC [colorectal cancer] mouse model.

Suboptimal intake of whole grains (38 g/d) was associated with CRC burden across 16 European countries. An optimal intake of 50–100 g/d was considered in our study to establish the dose administered in the AOM/DSS-induced CRC mouse model (75 g/d).

Seeds (100 g) were soaked in distilled water for 12 h then watered daily. Temperature and relative humidity were set at 25 °C and 60%. Germination was performed in darkness for five days. Germination percentage was determined based on total number of fully emerged seedlings.

We reached 100% of germination and a radicle length of 6.47 ± 0.22 cm. Sprouts were dried at 50 °C for 12 h, milled to a particle size of 0.5 mm, and stored at 4 °C until analyses.

Protein and lipid contents were higher in SO, whereas carbohydrate and ash contents were lower. A more than four-fold increase [0.64 mg/g to 2.79 mg/g] in TPC [total phenolic compounds] was obtained after five days.

We identified AVA-D as the most abundant AVA, followed by AVA-L, which had not been reported as one of the three most abundant AVAs in other oat varieties. Of the three most abundant AVAs previously reported, only AVA-B had a higher abundance in germination.

Phytic acid, an antinutritional compound present in oats, was 10 times lower in oat sprouts. Phytic acid has its content decreased by 15%–35% during even a short three-day germination due to activation of phytase activity. Although high doses of phytic acid inhibit absorption of metals and minerals in humans, it has been observed that, in small doses, it can function as a protective factor in several chronic degenerative diseases.

Mice in groups 3 and 4 were gavaged every morning with phenolic-AVA extract (0.084 mg GAE) and 30 mg of SO, respectively. We observed a mild anti-inflammatory effect of SO and AVA treatments, and a reduced adenocarcinoma incidence of 52.5% and 21.3%, respectively.

SO was more efficient in activating the Keap1-Nrf2 signaling pathway compared to treatment with AVA. Oat phenolic compounds together with β-glucans may be acting synergistically, thus offering greater protection for cancer prevention and treatment.”

https://www.mdpi.com/2304-8158/9/2/169/htm “Chemopreventive Effect of the Germinated Oat and Its Phenolic-AVA Extract in Azoxymethane/Dextran Sulfate Sodium (AOM/DSS) Model of Colon Carcinogenesis in Mice”

The supplementary material developed this oat cultivar’s seed and sprout profiles for 138 phenolic compounds. It measured C-type AVAs, but not A-type AVAs.

This was my model study for Sprouting whole oats.


A second study was reviewed in Eat oats today! and repeated here:

“The first evaluation of anti-inflammation effects of A-type AVAs was published from our own group. Fifteen A-type AVAs from commercial sprouted oat products interacted with lipopolysaccharide-induced nitric oxide production and iNOS expression.”

https://pubs.acs.org/doi/full/10.1021/acs.jafc.9b06812 “Quantitative Analysis and Anti-inflammatory Activity Evaluation of the A-Type Avenanthramides in Commercial Sprouted Oat Products” (not freely available)

Oat variety and sprout age weren’t available for the six sprouted oat products tested, so oat seed-to-sprout comparisons weren’t possible. A-type AVA comparisons among products were performed, but weren’t meaningful due to unknown varieties, ages, product processing, and storage.


A third study compared four grains’ sprouted and unsprouted contents:

“Seeds were soaked at 25°C in 1 L of distilled water for 20 (brown rice), 12 (sorghum and millet) and 8 h (oat), respectively. Hydrated grains were allowed to germinate with layering over wet cellulose pads in a humid chamber for 60 h at 25°C (oat seeds) or 30°C (brown rice, sorghum, and millet seeds) with 95% relative humidity.

All seeds derived from brown rice and oat were germinated after 48 h in the humid chamber. Germinated grains were dried at 50°C until reaching a moisture content of 10%. Sample seeds were milled to fine flour, screened through a 100-mesh sieve and stored at 4°C for further analysis.

After 60 h of germination, sprout length in sorghum and millet ranged from 8 to 24 mm, while sprouts obtained from brown rice and oat ranged from 3 to 6 mm.

Compared to raw flours, germinated flours derived from brown rice, sorghum, and millet had lower gelatinization enthalpy, whereas germinated oat flour showed higher gelatinization enthalpy.

During germination, enzymes are activated, catalyzing starch degradation, which may disrupt the double helical structure of starch. Consequently, less energy is required to unravel and melt double helices of starch in germinated flours. The increase in gelatinization enthalpy of germinated oat flour may be due to dissolution of hydrolyzed starch granules during germination.”

https://link.springer.com/article/10.1007%2Fs10068-020-00770-2 “Influence of germination on physicochemical properties of flours from brown rice, oat, sorghum, and millet” (not freely available)


The first study sprouted oats for five days to full germination and a minimum radicle length of 6.25 cm. The third study sprouted oats to full germination in 60 hours and a 3 mm minimum total length.

At the same 25°C, with 60% relative humidity and daily watering, it took 120 hours to achieve full germination. With 95% relative humidity, it took half that time.

Was humidity a relevant difference in oat sprout growth? Would Choyang variety oat sprouts increase their minimum 3 mm total length more than 20 times between Hours 60 and 120 to match the minimum Turquesa radicle length?

This is a count of PubMed “oat sprout” search results, 20 results total:

A “broccoli sprout” search returned 648 results. Is oat sprout research just getting started?

Eat oats today!

This 2020 food chemistry review provided phenolic-compound reasons to eat oats:

“Phenolamides result from the conjugation of hydroxycinnamic acids with amines. These products contain a variety of metabolic, chemical, and functional capabilities due to the large number of possible combinations among the parent compounds.

Of the currently known phenolamides, the most common are avenanthramides (AVAs), which are unique in oats. AVAs possess anti-inflammatory, anti-itch, anti-atherosclerosis, antioxidant, anti-cancer, anti-obesity, anti-fungal, anti-microbial, and neuroprotective properties.

Twenty-nine C-type AVAs have been identified in oats, and twenty-six A-type AVAs.

  • C-type AVAs in commercially available oat products range from 36.49-61.77 mg/kg (fresh weight).
  • A-type AVAs represent approximately 22.5% of total AVA levels in regular oats and 24.7-33.0% in commercial sprouted oats.

Steeping raw groats increased AVA concentrations.”

These reviews were referenced:

“Since publication of these two reviews, a few new studies reported AVAs’ beneficial health effects, mainly related to their anti-inflammatory and anti-cancer activities. AVAs can:

  • Significantly decrease IL-6, IL-8, and MCP-1 in endothelial cells;
  • Inhibit IL-1β- and TNF-α-induced NF-κB activation; as well as
  • Expression of adhesion molecules; and
  • Adhesion of monocytes to endothelial cell monolayer.

In 2020, the first evaluation of anti-inflammation effects of A-type AVAs was published from our own group. Fifteen A-type AVAs from commercial sprouted oat products interacted with lipopolysaccharide-induced nitric oxide production and iNOS expression.

Colloidal oatmeal’s natural components, AVAs, help to restore and maintain skin barrier function. AVAs are safe, well tolerated, and can be effective as adjuvant treatment in atopic dermatitis.

In one mouse model, a C-type AVA was able to mitigate many adverse effects of Alzheimer’s Disease. It restored hippocampal long-term potentiation and synaptic function, enhanced memory function, suppressed pro-inflammatory cytokines TNF-α and IL-6 levels, reduced caspase-3 levels, and increased pS9GSK-3β and IL-10 levels.

AVAs downregulated expression of hTERT and MDR1, pro-survival genes for cancer cells, and COX-2 mRNA and PGE2 levels, known pro-inflammatory markers. AVAs induced apoptosis by activating caspases 8, 3, and 2.”

https://pubs.acs.org/doi/10.1021/acs.jafc.0c02605 “The Chemistry and Health Benefits of Dietary Phenolamides” (not freely available)


Hadn’t thought about sprouting oats before this paper.

Clearing out the 2020 queue of interesting papers

I’ve partially read these 39 studies and reviews, but haven’t taken time to curate them.

Early Life

  1. Intergenerational Transmission of Cortical Sulcal Patterns from Mothers to their Children (not freely available)
  2. Differences in DNA Methylation Reprogramming Underlie the Sexual Dimorphism of Behavioral Disorder Caused by Prenatal Stress in Rats
  3. Maternal Diabetes Induces Immune Dysfunction in Autistic Offspring Through Oxidative Stress in Hematopoietic Stem Cells
  4. Maternal prenatal depression and epigenetic age deceleration: testing potentially confounding effects of prenatal stress and SSRI use
  5. Maternal trauma and fear history predict BDNF methylation and gene expression in newborns
  6. Adverse childhood experiences, posttraumatic stress, and FKBP5 methylation patterns in postpartum women and their newborn infants (not freely available)
  7. Maternal choline supplementation during the third trimester of pregnancy improves infant information processing speed: a randomized, double‐blind, controlled feeding study
  8. Preterm birth is associated with epigenetic programming of transgenerational hypertension in mice
  9. Epigenetic mechanisms activated by childhood adversity (not freely available)

Epigenetic clocks

  1. GrimAge outperforms other epigenetic clocks in the prediction of age-related clinical phenotypes and all-cause mortality (not freely available)
  2. Epigenetic age is a cell‐intrinsic property in transplanted human hematopoietic cells
  3. An epigenetic clock for human skeletal muscle
  4. Immune epigenetic age in pregnancy and 1 year after birth: Associations with weight change (not freely available)
  5. Vasomotor Symptoms and Accelerated Epigenetic Aging in the Women’s Health Initiative (WHI) (not freely available)
  6. Estimating breast tissue-specific DNA methylation age using next-generation sequencing data

Epigenetics

  1. The Intersection of Epigenetics and Metabolism in Trained Immunity (not freely available)
  2. Leptin regulates exon-specific transcription of the Bdnf gene via epigenetic modifications mediated by an AKT/p300 HAT cascade
  3. Transcriptional Regulation of Inflammasomes
  4. Adipose-derived mesenchymal stem cells protect against CMS-induced depression-like behaviors in mice via regulating the Nrf2/HO-1 and TLR4/NF-κB signaling pathways
  5. Serotonin Modulates AhR Activation by Interfering with CYP1A1-Mediated Clearance of AhR Ligands
  6. Repeated stress exposure in mid-adolescence attenuates behavioral, noradrenergic, and epigenetic effects of trauma-like stress in early adult male rats
  7. Double-edged sword: The evolutionary consequences of the epigenetic silencing of transposable elements
  8. Blueprint of human thymopoiesis reveals molecular mechanisms of stage-specific TCR enhancer activation
  9. Statin Treatment-Induced Development of Type 2 Diabetes: From Clinical Evidence to Mechanistic Insights
  10. Rewiring of glucose metabolism defines trained immunity induced by oxidized low-density lipoprotein
  11. Chronic Mild Stress Modified Epigenetic Mechanisms Leading to Accelerated Senescence and Impaired Cognitive Performance in Mice
  12. FKBP5-associated miRNA signature as a putative biomarker for PTSD in recently traumatized individuals
  13. Metabolic and epigenetic regulation of T-cell exhaustion (not freely available)

Aging

  1. Molecular and cellular mechanisms of aging in hematopoietic stem cells and their niches
  2. Epigenetic regulation of bone remodeling by natural compounds
  3. Microglial Corpse Clearance: Lessons From Macrophages
  4. Plasma proteomic biomarker signature of age predicts health and life span
  5. Ancestral stress programs sex-specific biological aging trajectories and non-communicable disease risk

Broccoli sprouts

  1. Dietary Indole-3-Carbinol Alleviated Spleen Enlargement, Enhanced IgG Response in C3H/HeN Mice Infected with Citrobacter rodentium
  2. Effects of caffeic acid on epigenetics in the brain of rats with chronic unpredictable mild stress
  3. Effects of sulforaphane in the central nervous system
  4. Thiol antioxidant thioredoxin reductase: A prospective biochemical crossroads between anticancer and antiparasitic treatments of the modern era (not freely available)
  5. Quantification of dicarbonyl compounds in commonly consumed foods and drinks; presentation of a food composition database for dicarbonyls (not freely available)
  6. Sulforaphane Reverses the Amyloid-β Oligomers Induced Depressive-Like Behavior (not freely available)

Part 2 of Eat broccoli sprouts for your eyes

I was a little bothered by an unreferenced statement in Eat broccoli sprouts for your eyes that:

“Once AGEs are formed, most are irreversible.”

I searched curated 2020 studies for “revers” and found that recent blog studies favored reversibility of epigenetic changes 12-to-2. Do they reflect my selection bias, or is there something different about AGEs?

Let’s start with this statement:

“Although AGEs are irreversible adducts and cross-links in our tissues, these can be removed through different proteolytic capacities:

  • The ubiquitin proteasome system (UPS) – Ubiquitin is a protein that when conjugated to a protein substrate can facilitate degradation of that substrate by the proteasome. Obsolete or damaged proteins are tagged with ubiquitin and these ubiquitinated substrates are degraded by the proteasome. Operates mainly on soluble substrates.
  • Autophagy – Can operate on insoluble substrates, including organelles such as mitochondria. Autophagy requires macromolecular assemblies and organelles to identify, sequester, and eventually degrade substrates via the lysosome.

Unfortunately, the function of both proteolytic pathways declines with extensive glycative stress and upon aging in many tissues, resulting in intracellular accumulation of protein aggregates (also glycated conjugates) and dysfunctional organelles. This thwarts strategies to lower AGEs accumulation by boosting proteolytic capacities.”

https://www.mdpi.com/2076-3921/9/11/1062/htm “Glyoxalase System as a Therapeutic Target against Diabetic Retinopathy”


So humans can remove irreversible AGE epigenetic changes as long as the individual isn’t too stressed or old? Studies from 2008 to 2012 were cited for the above statement and graphic.

Citation 211 Sulforaphane delays diabetes-induced retinal photoreceptor cell degeneration (not freely available) 2020 findings were instructive:

“SF [sulforaphane] can delay photoreceptor degeneration in diabetes. The underlying mechanism is related to:

  • Inhibition of ER [endoplasmic reticulum] stress;
  • Inflammation; and
  • Txnip [thioredoxin-interacting protein] expression through activation of the AMPK [adenosine 5′-monophosphate (AMP)-activated protein kinase] pathway.

Function of the retina in diabetic [DM] mice as determined by ERG [electroretinography].”


This chart demonstrated that preventing diabetes’ retinal effects (non-diabetic control bar) was measurably better than trying to fix them. Are future choices of humans who give themselves this non-communicable disease also limited to addressing symptoms?

The AMPK pathway was mentioned in:

  1. Reversal of aging and immunosenescent trends with sulforaphane:”

    Dihydroxyvitamin D3 and sulforaphane are compounds that safely induce AMPK activation, and may have wide-ranging implications for both normal and pathological aging.”

  2. Part 2 of Reversal of aging and immunosenescent trends with sulforaphane:

    “NQO1 plays a key role in AMPK-induced cancer cell death through the CD38/cADPR/RyR/Ca2+/CaMKII signaling pathway. Expression of NQO1 is elevated by hypoxia / reoxygenation or inflammatory stresses through nuclear accumulation of the NQO1 transcription factor, Nrf2. Activation of the cytoprotective Nrf2 antioxidant pathway by sulforaphane protects immature neurons and astrocytes from death caused by exposure to combined hypoxia and glucose deprivation.”

This first example was vitamin D3’s separate yet connected signaling pathway that acts both additively and synergistically with broccoli sprout compound effects. Followed by signaling pathways becoming cascadingly activated from sulforaphane’s main effect, Nrf2 signaling pathway activation.


Eat broccoli sprouts for your eyes

This 2020 review subject concerned a leading cause of blindness:

“Advanced glycation end products (AGEs) are toxic compounds that have adverse effects on many tissues including the retina and lens. AGEs promote the formation of reactive oxygen species (ROS), which, in turn, boost the production of AGEs, a vicious cycle.

Diabetic retinopathy (DR) is a devastating microvascular complication of diabetes mellitus and the leading cause of blindness in working-age adults. The onset and development of DR is multifactorial. Lowering AGEs accumulation may represent a potential therapeutic approach.

Once AGEs are formed, most are irreversible. Cataracts are perhaps the earliest pathobiology of AGEs:

Nε-(carboxymethyl)-lysine (CML) [a representative AGE] in lens crystallins from diabetic (■) and non-diabetic (♦) subjects as a function of age.

The glyoxalase system is a protective mechanism that slows down synthesis of AGEs by limiting reactive dicarbonyls formed during sugar metabolism. Glutathione (GSH) in the eye is present at concentrations many times blood levels, and is a critical component of the glyoxalase system.

Proteomic analysis identified GLO1 [glyoxalase 1] as a protein differentially expressed in cells treated with sulforaphane. Sulforaphane inhibited AGEs-derived pericyte damage and delayed diabetes-induced retinal photoreceptor cell degeneration.

No AGE inhibitors have reached clinical use. The glyoxalase system and discovery of compounds that enhance this detoxifying activity represent a therapeutic alternative to fight glycation-derived damage.”

https://www.mdpi.com/2076-3921/9/11/1062/htm “Glyoxalase System as a Therapeutic Target against Diabetic Retinopathy”


The above graph – plotting a cataract AGE level against chronological age – represented life stage progression without effective personal agency, without taking responsibility for your one precious life.

Citation 156 was Activation of Nrf2 attenuates carbonyl stress induced by methylglyoxal in human neuroblastoma cells: Increase in GSH levels is a critical event for the detoxification mechanism (not freely available):

“The present study focused on the methylglyoxal (MG) detoxification mechanism. MG treatment resulted in accumulation of modified proteins bearing the structure of AGEs.

This accumulation was suppressed by activation of the Nrf2 pathway prior to MG exposure via pre-treatment with an Nrf2 activator:

Although pre-treatment with the Nrf2 activator did not affect mRNA levels of GLO1, expressions of GCL and xCT mRNA, involved in GSH synthesis, were induced prior to increase in GSH levels.

These results indicated that increase in GSH levels promoted formation of the GLO1 substrate, thereby accelerating MG metabolism via the glyoxalase system and suppressing its toxicity. Promotion of GSH synthesis via the Nrf2/Keap1 pathway is important in MG detoxification.”

Continued in Part 2.


PXL_20201121_113656177

Nrf2 and Parkinson’s disease

This 2020 rodent study investigated a long non-coding RNA (lncRNA) in Parkinson’s disease:

“Knockdown of MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) lncRNA inhibited elevated nuclear factor (erythroid-derived 2)-like-2 factor (NRF2) expression, thereby inhibiting inflammasome activation and ROS (reactive oxygen species) production. MALAT1 was shown to promote neuroinflammation by recruiting enhancer of zeste homologue 2 (EZH2) to the promoter of NRF2, suppressing Nrf2 expression.

EZH2 catalyses generation of trimethylated H3K27 (H3K27me3) from histone H3 at lysine 27 (H3K27). EZH2 plays an important role in regulating the essential genes for inflammation in microglial activation, which induces neurodegeneration in the central nervous system.

Our results also validated MALAT1 binding to EZH2 in LPS-treated BV2 cells, which further recruited H3K27me3 to the gene promoter loci of Nrf2 to repress Nrf2 transcription. Although silencing MALAT1 did not alter global EZH2 expression levels, decreased binding between EZH2 and the Nrf2 promoter was observed. Previous studies have revealed that lncRNAs regulate the function of EZH2 in a similar manner.

MALAT1 epigenetically inhibits NRF2, thereby inducing inflammasome activation and ROS production in PD mouse and microglial cell models. To the best of our knowledge, it is first report of the important role of EZH2 in regulating the expression of Nrf2 to activate microglial inflammation.”

https://molecularbrain.biomedcentral.com/articles/10.1186/s13041-020-00656-8 “LncRNA MALAT1 facilitates inflammasome activation via epigenetic suppression of Nrf2 in Parkinson’s disease”


Eat broccoli sprouts today! referenced a letter to the editor that cited The Ezh2 Polycomb Group Protein Drives an Aggressive Phenotype in Melanoma Cancer Stem Cells and is a Target of Diet Derived Sulforaphane which found:

“SFN treatment is associated with reduced Ezh2 level and H3K27me3 formation.”

However, that study didn’t link sulforaphane’s main effect of Nrf2 signaling pathway activation to these specific treatment effects.

This post was inspired by our latest subscriber, Dr. Albert F. Wright, who is battling PD with – among other treatments – broccoli seeds.


Sulforaphane in the Goldilocks zone

This 2020 paper reviewed hormetic effects of a broccoli sprout compound:

“Sulforaphane (SFN) induces a broad spectrum of chemoprotective effects across multiple organs that are of importance to public health and clinical medicine. This chemoprotection is dominated by hormetic dose responses that are mediated by the Nrf2/ARE pathway and its complex regulatory interactions with other factors and pathways, such as p53 and NF-κB.

The stimulatory zone for in vitro studies proved to be consistently in the 1-10 μM range. Hormetic studies of SFN strongly targeted activation of Nrf2.

Capacity to activate Nrf2 diminishes with age, and may affect capacity of SFN to effectively enhance adaptive responses.

A 4-hour exposure induced a 24 hour Nrf2-mediated increase in enzymes that reduce free-radical damage in neurons and astrocytes. Repeated 4-hour treatment for four days affected an accumulation along with a persistent protection.

In the case of continuous exposure to SFN, such as taking a daily supplement, SFN treatment did not result in an accumulation of HMOX1 [heme oxygenase (decycling) 1 gene] mRNA or protein. This suggested that HMOX1 response may experience feedback regulation, avoiding possible harmful overproduction.”

https://www.sciencedirect.com/science/article/abs/pii/S1043661820315917 “The phytoprotective agent sulforaphane prevents inflammatory degenerative diseases and age-related pathologies via Nrf2-mediated hormesis” (not freely available)


One coauthor has been on a crusade to persuade everybody of this paradigm. Hormesis’ hypothesis isn’t falsifiable in all circumstances, however.

Hormetic effects may be experimental considerations. But what’s the point of performing sulforaphane dose-response experiments in contexts that are physiologically unachievable with humans? Two examples:

  1. Autism biomarkers and sulforaphane:

    “There was no concentration-dependence in the induction of any of the genes examined, with the higher (5 μM) concentration of SF even showing a slightly diminished effect for the induction of AKR1C1 and NQO1. Although this concentration is achievable in vivo, more typical peak concentrations of SF (and its metabolites) in human plasma are 1-2 μM.”

  2. Human relevance of rodent sulforaphane studies:

    “Over two-thirds of the animal studies have used doses that exceed the highest (and bordering on intolerable) doses of sulforaphane used in humans. The greater than 4-log spread of doses used in mice appears to be driven by needs for effect reporting in publications rather than optimization of translational science.”

This paper cited many hormetic effects that were human-irrelevant without making a distinction. It also had parts such as:

“The capacity for high concentrations of AITC [allyl isothiocyanate] to enhance genetic damage is not relevant since such high concentrations are not realistically achievable in normal human activities.

Humans ingest only the R-isomer of SFN via diet. Their dosing strategy adopted concentrations of R-SFN that were less than those employed to induce cytotoxic effects in cancer cells and that simulated its consumption as a dietary supplement.”


Landing eagle

If it stinks, it’s good for you

This 2019 review subject was hydrogen sulfide and broccoli sprout compounds:

“Release of H2S was identified as a hidden mechanism responsible for effects of natural compounds that were used for a long time for pharmacological, therapeutic or nutraceutical purposes. For instance, the release of H2S was recognized as the main mechanism accounting for the biological effects of garlic.

There is evidence of a close overlap between numerous physiological / biological effects attributed to natural ITCs [isothiocyanates] and H2S. They both behave as antioxidant and anti-inflammatory agents, are activators of potassium channels modulating a vasodilatory effect, and are chemopreventive agents. Moreover, an impressive overlap can be observed in the molecular mechanisms of action.

Vascular inflammation results from the persistence of oxidative and/or inflammatory stimuli on the endothelium and vascular smooth muscle. These types of stimuli can be a consequence of prolonged status of mild inflammation and are typical in certain metabolic / cardiovascular diseases, spreading to all organs and tissues.

Advanced glycation end products (AGEs) are responsible for an increase in LDL. Binding of AGEs to their receptors RAGE results in an increase in intracellular ROS generation and in activation of NF-kB. Oral consumption of SFN [sulforaphane] precursor-rich broccoli sprouts decreases the serum levels of AGEs in humans.

Inflammatory response plays a pivotal role in initiation and maintenance of chronic neuropathic pain. Inhaling low concentrations of H2S protects motor neurons from degeneration and delayed paraplegia in a mouse model of sciatic constriction injury. This effect has been ascribed to the activation of the Nrf2 pathway.

Dose-dependent rise of the pain threshold mediated by SFN was fully prevented by simultaneous administration of hemoglobin, confirming that H2S is likely to be the real player in ITC-induced analgesia. Kv7 channel activation can be considered one of the main mechanisms in the antinociceptive activity of H2S-releasing drugs.”

https://www.liebertpub.com/doi/10.1089/ars.2019.7888 “Organic Isothiocyanates as Hydrogen Sulfide Donors” (not freely available)


These reviewers were long on equivalencies and short on proofs. Unlike study researchers, reviewers aren’t bound to demonstrate evidence from tested hypotheses. Reviewers are free to:

  • Express their beliefs as facts;
  • Over/under emphasize study limitations; and
  • Disregard and misrepresent evidence as they see fit.

Study researchers are obligated to provide detailed analyses of why observed effects couldn’t have been produced from unobserved causes. That didn’t happen here.

Eat broccoli sprouts to inhibit β-amyloid

This 2020 lab study investigated sulforaphane’s effects on an Alzheimer’s disease enzyme:

“BACE1 is the rate-limiting enzyme responsible for the production of Aβ [amyloid-beta] from APP [amyloid precursor protein]. Both the expression level and activity of this enzyme are aberrantly elevated in the brains of patients with AD.

Sulforaphane exhibited six times more potent activity against BACE1 compared to well-known positive controls including resveratrol and quercetin. Sulforaphane presented selective and non-competitive BACE1 inhibitory activity with low off-target inhibition.

Molecular docking simulation was used to analyze whether the compound can reach the target enzyme to produce the biological effect safely and interact with the targeted sites.

The blood–brain barrier (BBB) is constituted by neurovascular units that contain endothelial cells. A previous study reported that gavage administration of sulforaphane penetrated BBB in its intact structure and accumulated in brain tissues with a maximum increase and disappearance after 15 min and 2 h, respectively.”

https://www.mdpi.com/2072-6643/12/10/3026/htm ” Discovery of Sulforaphane as a Potent BACE1 Inhibitor Based on Kinetics and Computational Studies”


Eat broccoli sprouts to pivot your internal environment’s signals

Two 2020 reviews covered some aspects of a broccoli sprouts primary action – NRF2 signaling pathway activation:

“Full understanding of the properties of drug candidates rely partly on the identification, validation, and use of biomarkers to optimize clinical applications. This review focuses on results from clinical trials with four agents known to target NRF2 signaling in preclinical studies, and evaluates the successes and limitations of biomarkers focused on:

  • Expression of NRF2 target genes [AKR1, GCL, GST, HMOX1, NQO1] and others [HDAC, HSP];
  • Inflammation [COX-2, CRP, IL-1β, IL-6, IP-10, MCP-1, MIG, NF-κB, TNF-α] and oxidative stress [8-OHdG, Cys/CySS, GSH/GSSG] biomarkers;
  • Carcinogen metabolism and adduct biomarkers in unavoidably exposed populations; and
  • Targeted and untargeted metabolomics [HDL, LDL, TG].

No biomarkers excel at defining pharmacodynamic actions in this setting.

SFN [sulforaphane] seems to affect multiple downstream pathways associated with anti-inflammatory actions. NRF2 signaling may be but one pivotal pathway.

SFN is generally considered to be the most potent natural product inducer of Nrf2 signaling. Studies in which these actions are diminished or abrogated in parallel experiments in Nrf2-disrupted mice provide the strongest lines of evidence for a key role of this transcription factor in its actions.

It is equally evident that other modes of action contribute to the molecular responses to SFN in animals and humans. Such polypharmacy may well contribute to the efficacy of the agent in disease prevention and mitigation, but obfuscates the value of specific pharmacodynamic biomarkers in the clinical development and evaluation of SFN.”

https://www.mdpi.com/2076-3921/9/8/716/htm “Current Landscape of NRF2 Biomarkers in Clinical Trials”


Why do researchers still not use epigenetic clocks in sulforaphane clinical trials? Forty mentions of disease in this review, but no consideration of aging?

This was another example of how researchers – even when stuck in a paradigm they know doesn’t sufficiently explain their area (“No biomarkers excel”) – don’t investigate other associated research areas. Why not?

Here’s what Part 2 of Rejuvenation therapy and sulforaphane had to say to those stuck on biomarkers:

“While clinical biomarkers have obvious advantages (being indicative of organ dysfunction or disease), they are neither sufficiently mechanistic nor proximal to fundamental mechanisms of aging to serve as indicators of them. It has long been recognized that epigenetic changes are one of several primary hallmarks of aging.

DNA methylation epigenetic clocks capture aspects of biological age.”


The second review Epigenetic Regulation of NRF2/KEAP1 by Phytochemicals also completely whiffed on epigenetic clocks. One mention of aging in this review, but it wasn’t of:

  • Citation 104 from Archives of Gerontology and Geriatrics; nor of
  • Citation 108 from the March 31, 2020, Aging journal; nor of
  • Citation 131 “Dietary epigenetics in cancer and aging.”

But epigenetic clock and aging associations were certainly in this review’s scope. For example, Citation 119 said:

“Nrf2 transcriptional activity declines with age, leading to age-related GSH loss among other losses associated with Nrf2-activated genes. This effect has implications, too, for decline in vascular function with age. Some of the age-related decline in function can be restored with Nrf2 activation by SFN.”

Why would people bother with phytochemicals (buzzword “compounds produced by plants”) unless to either ameliorate symptoms or address causes?

“Epigenetic Regulation of NRF2/KEAP1 by Phytochemicals” doesn’t occur in just laboratory situations. It’s also part of daily life.

These reviewers were straight-forward with side effects for two of the first review’s four items:

“The best known NRF2 activator that has obtained clinical approval is dimethyl fumarate for the treatment of multiple sclerosis. However, it has several side effects, including allergic reactions and gastrointestinal disturbance. There are a few related agents in clinical trials, such as Bardoxolone and SFX-01, a synthetic derivative of sulforaphane, which also exhibit less than desirable outcomes.”


Treating psychopathological symptoms will somehow resolve causes?

This 2020 Swiss review subject was potential glutathione therapies for stress:

“We examine the available data supporting a role for GSH levels and antioxidant function in the brain in relation to anxiety and stress-related psychopathologies. Several promising compounds could raise GSH levels in the brain by either increasing the availability of its precursors or the expression of GSH-regulating enzymes through activation of Nrf2.

GSH is the main cellular antioxidant found in all mammalian tissues. In the brain, GSH homeostasis has an additional level of complexity in that the expression of GSH and GSH-related enzymes are not evenly distributed across all cell types, requiring the coordination between neurons and astrocytes to neutralize oxidative insults.

Increased energy demand in situations of chronic stress leads to mitochondrial ROS overproduction, oxidative damage and exhaustion of GSH pools in the brain.

Several compounds can function as precursors of GSH by acting as cysteine (Cys) donors such as taurine or glutamate (Glu) donors such as glutamine (Gln). Other compounds stimulate the synthesis and recycling of GSH through the activation of the Nrf2 pathway including sulforaphane and melatonin. Compounds such as acetyl-L-carnitine can increase GSH levels.”

https://www.sciencedirect.com/science/article/abs/pii/S0149763419311133 “Therapeutic potential of glutathione-enhancers in stress-related psychopathologies” (not freely available)


Many animal studies of “stress-related psychopathologies” were cited without noting applicability to humans. The reviewers instead had curious none-of-this-means-anything disclaimers like:

“Comparisons between studies investigating brain disorders of such different nature such as psychiatric disorders or neurodegenerative diseases, or even between brain or non-brain related disorders should be made with caution.”

Regardless, this paper had informative sections for my 27th week of eating broccoli sprouts every day.

1. I forgot to mention in Broccoli sprout synergies that I’ve taken 500 mg of trimethyl glycine (aka betaine) twice a day for over 15 years. Section 3.1.2 highlighted the amino acid glycine:

“Endogenous synthesis is insufficient to meet metabolic demands for most mammals (including humans) and additional glycine must be obtained from the diet. While most research has focused on increasing cysteine levels in the brain in order to drive GSH synthesis, glycine supplementation alone or in combination with cysteine-enhancing compounds are gaining attention for their ability to enhance GSH.”

2. The amino acid taurine dropped off my supplement regimen last year after taking 500 mg twice a day for years. It’s back on now after reading Section 3.1.3:

“Most studies that reported enhanced GSH in the brain following taurine treatment were performed under a chronic regimen and used in age-related disease models. Such positive effects of taurine on GSH levels may be explained by the fact that cysteine is the essential precursor to both metabolites, whereby taurine supplementation may drive the metabolism of cysteine towards GSH synthesis.

3. A study in Upgrade your brain’s switchboard with broccoli sprouts was cited for its potential:

“Thalamic GSH values significantly correlated with blood GSH levels, suggesting that peripheral GSH levels may be a marker of brain GSH content. Studies point to the capacity of sulforaphane to function both as a prophylactic against stress-induced behavioral changes and as a positive modulator in healthy animals.”


Sunrise minus 5 minutes

Jet fuel exposure causes diseases in the great-grand offspring

This 2020 Washington State University rodent study examined how great-grandmothers’ JP-8 exposures produced diseases in their great-grand offspring:

“Ancestral exposure to environmental influences such as toxicants, abnormal nutrition, and traumatic stress can affect the germline epigenome and promote the epigenetic transgenerational inheritance of adult onset disease in various organisms from plants to humans. Biological mechanisms underlying transgenerational epigenetic inheritance induced by jet fuel exposure are further investigated in the current study.

Genome-wide association studies (GWAS) have found specific genetic mutations associated with human pathologies, however these genetic mutations generally appear in less than 1% of the disease population. In contrast, epimutations (DNA methylation, histone modifications, non-coding RNA, chromatin structure, and RNA methylation alterations) seem to have a higher frequency and appear in more individuals with the diseases. Determining epigenetic biomarkers for these diseases could become especially useful indicators of environmental exposures and disease susceptibility in the human population.

The number of differential methylated regions (DMRs) found in the transgenerational F3 males is between 100 and 500 for each individual pathology. Few DMRs overlap between the different pathologies which supports the possible use of epimutations as biomarkers of disease. Although further studies are required, the lack of a subpopulation of DMRs overlapping with all pathologies suggests that at a more stringent statistical threshold there are not common DMRs among specific diseases.

Although females develop transgenerational disease, insufficient numbers of oocytes can be obtained on individuals to allow epigenetic associations to be assessed. The study only examined male pathology and associated sperm epimutation associations.”

https://www.sciencedirect.com/science/article/pii/S0890623820301982 “Epigenome-wide association study for transgenerational disease sperm epimutation biomarkers following ancestral exposure to jet fuel hydrocarbons”


The only associations these study subjects had with JP-8 were their great-grandmothers’ jet fuel exposures while pregnant with their grandparents. Other environmental toxicants studied by this group that produced similar transgenerationally inherited diseases were DDT, atrazine, and vinclozolin.

Ever think about your great-grandchildren?