Neurochemicals

Plasmalogens Week #7 – Genes

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Continuing Plasmalogens Week with three 2025 papers, starting with a rodent study of genetically deleting a plasmalogen catabolizing enzyme:

“In this study, we investigated the impact of global and tissue-specific loss-of-function of a plasmalogen catabolizing enzyme, lysoplasmalogenase (TMEM86B), on circulatory and tissue lipidomes. Mice with homozygous global inactivation of Tmem86b (Tmem86b KO mice) were viable and did not display any marked phenotypic abnormalities.

Tmem86b KO mice demonstrated significantly elevated levels of plasmalogens alkenyl phosphatidylethanolamine (PE(P)) and alkenyl phosphatidylcholine (PC(P)), as well as lysoplasmalogens, in the plasma, liver, and natural killer cells compared to their wild-type counterparts. The endogenous alkenyl chain composition of plasmalogens remained unaltered in Tmem86b KO mice. Consistent with the global knockout findings, hepatocyte-specific Tmem86b knockout mice also exhibited increased plasmalogen levels in the plasma and liver compared to their floxed control counterparts.

Plasmalogens may be synthesized locally within various tissues, with each organ possessing the necessary enzymatic machinery to regulate its own plasmalogen levels. Plasmalogens are important structural constituents of the biological membranes of animals and certain anaerobic bacteria, and have several well-described functions, including regulating membrane dynamics and vesicular cholesterol transport and homeostasis.

  • One of the most interesting features of plasmalogens is their endogenous antioxidant activity, which is mostly due to the vinyl ether bond, which can scavenge reactive oxygen species and thereby protect other biomolecules from oxidative damage.
  • They increase the gene expression of multiple antioxidant enzymes to protect against chemically induced cytotoxicity and lipid peroxidation in cultured hepatocytes.
  • Plasmalogen derivatives such as polyunsaturated fatty acids (AA or DHA) and lysoplasmalogens can act as lipid mediators for multiple cellular signaling activities.
  • Plasmalogens are important for phagocytosis of macrophages, lipid droplet formation, and development and function of neuromuscular junctions.
  • They play vital roles in mediating immune responses, and mitochondrial fission to regulate adipose tissue thermogenesis, and protecting neuronal cells against cell death and inflammation.

All of these are suggestive of a critical role played by plasmalogens in maintaining cellular homeostasis.

While plasmalogen anabolism is well defined, its catabolism has been less studied. During catabolism, plasmalogens are deacylated by the action of a calcium-independent phospholipase A2 enzyme (iPLA2) to produce lysoplasmalogens. However, cytochrome C has also been shown to act as a plasmalogenase under certain circumstances.

The amount of lysoplasmalogens in cells is tightly regulated either by reacylation into plasmalogens through a coenzyme A-independent transacylase, or by degradation into fatty aldehydes and glycerophospholipids by an alkenyl ether hydrolase commonly known as lysoplasmalogenase. Lysoplasmalogenase is a microsomal transmembrane enzyme highly specific for lysoplasmalogens, and has no activity against plasmalogens.

While research on the distinct biological functions of lysoplasmalogens and plasmalogens is lacking, some reports indicate potential toxic effects of lysoplasmalogens. Degradation products of lysoplasmalogens, such as fatty aldehydes, are highly reactive electrophilic compounds that can form toxic adducts with cellular proteins and lipids. These interactions can lead to cellular dysfunction and contribute to various pathological conditions. Their accumulation in ischemic/reperfused tissues has been associated with cellular damage.

However, we observed that the amount of lysoplasmalogens as a proportion of total plasmalogens in the liver of Tmem86b KO mice was only ∼3.5%, indicating that elevated lysoplasmalogens are rapidly converted into plasmalogens within the liver. In adipose tissue-specific Tmem86a KO mice, which also exhibited higher lysoplasmalogens, no toxic effects were observed. Instead, these mice showed elevated mitochondrial oxidative metabolism and energy expenditure, offering protection from high-fat diet-induced metabolic dysfunction. These findings suggest that any potential toxic effects of lysoplasmalogens are largely mitigated by their rapid reacylation into plasmalogens.

This study enhances our understanding of regulatory mechanisms governing plasmalogen metabolism, and highlights the potential of targeting Tmem86b to therapeutically raise plasmalogen levels.”

https://www.jlr.org/article/S0022-2275(25)00068-9/fulltext “Modulation of endogenous plasmalogens by genetic ablation of lysoplasmalogenase (Tmem86b) in mice”

An independent researcher published a commentary on the above study:

“While the biosynthesis of this particular lipid subclass, starting in the peroxisomes and ending at the endoplasmic reticulum, has been the subject of extensive research, the degradation pathway of these compounds remains to be further elucidated. Plasmalogen breakdown is a complex process involving enzymatic hydrolysis, oxidative cleavage, and possibly also a recycling mechanism.

A fundamental unresolved question in the field of plasmalogen catabolism is which of the two possible reaction routes is actually the more important one. Either 1) directly via plasmalogenase or 2) via a deacylation step by a plasmalogen-specific phospholipase A2 (cPLA2, PLA2G4A), yielding a lysoplasmalogen as the first degradation product, and subsequent hydrolysis of the ether bond by a lysoplasmalogenase such as TMEM86A and TMEM86B. It is also unclear how these pathways interact or compensate for each other, how they are regulated, and whether they are tissue- or cell type–specific.

To make the story even more complex, a CoA-independent transacylase activity was described that reacylates lysoplasmalogen intermediates back to plasmalogens by transferring polyunsaturated fatty acids to the vacant sn-2 position of ether lysophospholipids. But no gene for this enzyme has so far been identified.

Why is plasmalogen breakdown so important? Disturbances in plasmalogen metabolism are associated with several human disorders. Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis have been shown to be associated with reduced levels of plasmalogens.

Unfortunately, it is still too early to draw conclusions about the individual roles of TMEM86A and TMEM86B, as their cellular localisation and function are not sufficiently studied, and reliable antibodies for these proteins are not yet available. Localization of the two TMEM86 homologs overlaps to some extent, as shown, for example, by their gene expression in small intestine. However, whether one isoform is able to compensate for a deficiency in the other is uncertain, and was not found in small intestine of Tmem86b knockout mice [in the above study].

In contrast to the two proteins TMEM86A and TMEM86B, cytochrome c is much better studied. It is associated with the inner mitochondrial membrane, and can be released into the cytosol during apoptosis. It has a wide tissue distribution with most abundant gene expression levels in the digestive tract and heart.“

https://www.jlr.org/article/S0022-2275(25)00074-4/fulltext “Plasmalogen. Quo vadis?”

The statement “no gene for this enzyme has so far been identified” revealed a paradigm. But maybe what’s being observed evolved before genes?

One example of this principle is from the 1966 https://www.science.org/doi/10.1126/science.152.3720.363 “Evolution of the Structure of Ferredoxin Based on Living Relics of Primitive Amino Acid Sequences” which provided evidence pointing to heme protein evolution beginning before gene evolution. Its abstract included this statement:

“We explain the persistence of living relics of this primordial structure by invoking a conservative principle in evolutionary biochemistry: The processes of natural selection severely inhibit any change in a well-adapted system on which several other essential components depend.”

Maybe the process of reassembling plasmalogen breakdown products back into plasmalogens without involving a specific gene likewise became essential?

A role of plasmalogens in diabetic kidney disease was found in a third study that investigated a genetic rodent model of diabetes:

“Diabetic nephropathy (DN) represents a frequent cardiovascular complication of diabetes, affecting about 20–50% of individuals with the disease. Globally, it constitutes a primary etiology for end-stage kidney disease (ESKD) and chronic kidney disease (CKD), while also serving as a significant independent risk factor for cardiovascular morbidity and mortality.

Although intensive management strategies targeting blood pressure and glucose levels demonstrably attenuate the risk of DN development, they do not confer complete protection. This residual risk strongly implicates pathogenic factors beyond impaired glucose metabolism and hemodynamic alterations in DN pathogenesis.

In the present study, we employed the db/db mice as the DN model. When compared to other diabetes models, such as those induced by streptozotocin (STZ) or high-fat diet combined with STZ, the db/db model more accurately recapitulates the pathological features of human type 2 diabetes mellitus (T2DM). It also possesses a stable genetic background, making it particularly well-suited for the investigation of diabetes complications.

Transcriptomics revealed extensive dysregulation of metabolic and lipid regulatory pathways in db/db. Lipidomics uncovered pronounced abnormalities in cardiolipin species composition and plasmalogen profiles. Transcriptome-lipidome integration demonstrated impaired phosphatidylcholine (PC) biosynthesis, mechanistically linked to dysregulation of choline phosphotransferase 1 (chpt1), which correlated significantly with compromised tissue regeneration capacity.

Volcano plot analysis delineated specific lipid alterations, particularly in plasmalogen species in plasmalogen lipids. Plasmenylcholines (plas-PC) and plasmenylethanolamine (plas-PE) containing n-3 polyunsaturated fatty acids (PUFAs) were significantly decreased in the kidneys of db/db mice. Conversely, plas-PCs and plas-PEs esterified with n-6 PUFAs showed substantial accumulation in diabetic kidneys.

In conclusion, the highly sensitive and extensively targeted UHPLC-MS/MS methodology enabled a more in-depth characterization of renal metabolic and lipid perturbations in db/db mice. These alterations principally reflect the sustained inflammatory milieu and compromised antioxidant defenses characteristic of DN renal tissues.”

https://www.csbj.org/article/S2001-0370(25)00301-0/fulltext “Multi-omics characterization of diabetic nephropathy in the db/db mouse model of type 2 diabetes”

Plasmalogens Week #5 – Health and Diseases, Part 1

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Continuing Plasmalogens Week with three 2025 papers, starting with a human study that included plasmalogen biomarkers of non-communicable disease fatigue symptoms:

“This study explored the biological mechanisms underlying fatigue in patients with NCDs using a multi-omics approach. Our findings indicate that distinct metabolic pathways, salivary microbiota, and genetic factors may contribute to different dimensions of fatigue, including general, physical, and mental fatigue.

  • General fatigue is associated with unsaturated fatty acid biosynthesis, indicating its role in lipid metabolism.
  • Physical fatigue was associated with plasmalogen synthesis, mitochondrial beta-oxidation of long-chain fatty acids, and selenoamino acid metabolism, suggesting a potential contribution of impaired energy production.
  • Mental fatigue is associated with homocysteine degradation and catecholamine biosynthesis, which may influence cognitive fatigue.

This exploratory study suggests that fatigue in patients with NCDs may involve disruptions in lipid metabolism, neurotransmitter pathways, microbial composition, and genetic variations. Blood-based biomarkers showed better predictive potential for physical fatigue, whereas salivary-based models were more indicative of mental fatigue.

Although our findings support the role of lipid metabolism, the contribution of plasmalogen synthesis remains underexplored. Further studies are needed to validate these findings and understand their mechanisms of action.”

https://link.springer.com/article/10.1186/s12911-025-03034-3 “Visualizing fatigue mechanisms in non-communicable diseases: an integrative approach with multi-omics and machine learning”

A human study of metabolic dysfunction-associated steatotic liver disease (MASLD) included investigating plasmalogens:

“In this study, we applied untargeted metabolomic profiling to serum samples from individuals with and without MASLD, classified by the Fatty Liver Index, with the goal of identifying characteristic metabolic signatures and pathways that may underlie disease presence and progression. Individuals in the MASLD group displayed significantly higher levels of ALT, AST, ALP, and GGT, reflecting ongoing hepatic injury, cholestasis, and oxidative stress. However, albumin and bilirubin levels remained within normal limits, indicating early to intermediate disease stages rather than advanced fibrosis or cirrhosis.

A consistent and highly significant lipidomic pattern in the MASLD group is the depletion of plasmalogens and sphingomyelins. Depletion of these lipid classes was identified as a hallmark of insulin resistance as defined by the triglyceride-glucose index. In contrast, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol species were elevated in MASLD, pointing toward broader lipid remodeling events.

Reduced plasmalogen and sphingomyelin levels positions their depletion as a core feature of metabolic dysfunction. Plasmalogens are ether phospholipids with strong antioxidant capacity, and their reduction suggests a loss of protective buffering against oxidative stress, one of the main drivers of MASLD progression. Similarly, sphingomyelin depletion implicates altered membrane dynamics and signaling disturbances, further contributing to metabolic dysfunction.

Depletion of plasmalogens 1-(1-enyl-palmitoyl)-2-oleoyl-GPC (P-16:0/18:1), 1-(1-enyl-palmitoyl)-2-linoleoyl-GPC (P-16:0/18:2), 1-(1-enyl-palmitoyl)-2-palmitoyl-GPC (P-16:0/16:0), 1-(1-enyl-palmitoyl)-2-palmitoleoyl-GPC (P-16:0/16:1), 1-(1-enyl-palmitoyl)-2-oleoyl-GPE (P-16:0/18:1), 1-(1-enyl-palmitoyl)-2-linoleoyl-GPE (P-16:0/18:2), and disruption of the glutamate–gamma-glutamyl pathway stand out as central features of metabolic dysfunction in MASLD, with clear potential to inform biomarker discovery, disease classification, and the design of targeted therapeutic strategies.”

https://www.mdpi.com/2218-1989/15/11/687 “Metabolomic Signatures of MASLD Identified by the Fatty Liver Index Reveal Gamma-Glutamyl Cycle Disruption and Lipid Remodeling”

A rodent study investigated dietary sea squirt (AM) plasmalogen ethanolamine (PlsEtn) extract’s and dietary pig liver (PL) phosphatidyl ethanolamine (PtdEtn) extract’s effects on acetaminophen liver injury:

“We investigated dietary effects of PlsEtn from ascidian on chronic hepatic injury in acetaminophen (APAP)-treated mice. Five-week-old male mice were divided into four groups (n = 12), which were treated with experimental diets for two weeks and then the respective APAP-containing diet for five weeks.

Ingested PlsEtn is digested into lysoPlsEtn and free fatty acid in the small intestine. PlsEtn digests are absorbed and are subsequently resynthesized into PlsEtn preferentially with PUFA.

Acetaminophen is a frequently used analgesic and antipyretic. Approximately 90% of APAP is metabolized by UDP-glucuronosyltransferase and sulfotransferase into glucuronic acid and sulfate conjugates, respectively.

5–9% of APAP is metabolized into the highly reactive intermediate N-acetyl-p-benzoquinone imine (NAPQI). This metabolite is considered a pivotal molecule in APAP-induced hepatotoxicity and is conjugated by glutathione (GSH). Excessive NAPQI levels deplete GSH and covalently bind to cellular proteins, resulting in organelle dysfunction, such as mitochondria dysfunction. These impairments induce oxidative stress, cell malfunctions, and subsequently, cell death, such as ferroptosis and apoptosis.

Mice were treated with continuous APAP consumption to induce oxidative stress and impaired lipid metabolism in the liver. Effects of diets were evaluated based on levels of malondialdehyde (MDA), a marker of lipid oxidation, on fatty acid content, and on expression of apoptosis-related proteins in the liver.

The PlsEtn-rich diet effectively suppressed APAP-induced decrease in body and liver weights of mice. However, this suppressive effect was not observed in mice fed a PtdEtn-rich diet. APAP administration decreased the total fatty acid content in the liver, whereas a PlsEtn-rich diet alleviated this decrease and increased the hepatic content of docosahexaenoic acid (DHA).

Owing to the alkenyl linkage, which exhibits antioxidant properties, PlsEtn was expected to markedly suppress hepatic lipid oxidation. However, its suppressive effect was the same extent as that by PtdEtn. Both PlsEtn and PtdEtn contain an ethanolamine base in their structures, and free ethanolamine and its metabolite choline suppress lipid peroxidation. Dietary PlsEtn and PtdEtn may be metabolized into free ethanolamine and its further metabolites, which may alleviate APAP-induced hepatic lipid oxidation.

Dietary ethanolamine glycerophospholipids (EtnGpls) rich in PlsEtn or PtdEtn suppressed APAP-induced lipid oxidation in the liver. Protein expression results revealed that dietary EtnGpls reduced expression of certain apoptosis-related proteins compared to the APAP group. This reduction was more effective in mice fed the PlsEtn-rich diet than in those on the PtdEtn-rich diet.”

https://www.mdpi.com/2076-3417/15/11/5968 “Dietary Ethanolamine Plasmalogen from Ascidian Alleviates Chronic Hepatic Injury in Mice Treated with Continuous Acetaminophen”

This study neither demonstrated nor provided citations for its dietary plasmalogen recycling statements.

Three more plasmalogen health and disease papers are curated in Part 2.

A Nrf2 treatment for ALS?

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A 2025 rodent in vivo / human cell ex vivo study investigated effects of a Nrf2 activator on ALS rodent models and ALS human nervous system cells:

“M102 is a central nervous system (CNS) penetrant small molecule electrophile which activates in vivo the NF-E2 p45-related factor 2-antioxidant response element (NRF2-ARE) pathway, as well as transcription of heat-shock element (HSE) associated genes. Apart from the recent promising emergence of tofersen as a disease modifying therapy for the 2% of ALS patients who harbor mutations in the SOD1 gene, other approved drugs have only marginal effects on life expectancy (riluzole) or indices of disease progression (edaravone).

Data from disease model systems and from human biosamples provide strong evidence for a role of redox imbalance, inflammation, mitochondrial dysfunction, and altered proteostasis, including autophagy and mitophagy, as four key drivers in the pathobiology of ALS. We demonstrate that M102 is a dual activator of NRF2 and HSF1 transcription factor pathways, two upstream master regulators of neuroprotective mechanisms, with the potential to modulate all four of these key drivers of neurodegeneration and with excellent penetration across the blood brain barrier.

Stress response of the KEAP1-Nrf2-ARE system is stronger in astrocytes compared to neurons. A body of evidence from in vitro and in vivo model systems and from post-mortem CNS tissue from ALS patients has indicated that the NRF2 response is impaired in ALS, and has also been shown to decline with age.

HSF1 is a stress-inducible transcription factor that is the key driver for expression of multiple heat shock proteins which act as chaperones responsible for correct folding of newly synthesized proteins, refolding of denatured proteins, and prevention of aggregation of misfolded proteins. However, to date, many small molecule activators of HSF-1 have shown undesirable properties e.g. by acting as Hsp90 inhibitors or by exerting direct proteotoxic effects.

M102 (S-apomorphine hydrochloride hemihydrate) is a proprietary new chemical entity (NCE) and the S-enantiomer of the marketed R-apomorphine (Apokyn®; pure R-enantiomer). The R-enantiomer is a dopamine agonist administered subcutaneously for management of advanced Parkinson’s disease. M102 is a very weak dopamine antagonist and does not show the adverse effects associated with dopamine agonism.

M102 treatment rescues motor neuron (MN) survival in co-cultures with C9, SOD1 and sporadic ALS patient-derived astrocytes. Other NRF2 activators have been investigated in clinical trials or have been approved for medical use. These include dimethylfumarate (DMF) (Tecfidera®, Biogen) and omaveloxolone (Reata, Biogen).

  • DMF was originally approved for the treatment of psoriasis (Fumaderm®) and was later repurposed for the treatment of relapsing-remitting multiple sclerosis (Tecfidera®). A phase 2 trial of DMF in ALS provided Class 1 evidence of safety at a dose of 480 mg/day and lack of disease-modifying efficacy. DMF treatment is associated with dose-limiting lymphopenia and flushing (Tecfidera® Prescribing Information).
  • Omaveloxolone (Skyclarys®) is a potent NRF2 activator that has been approved by the FDA and EMA for the treatment of Friedreich’s ataxia. By activating the NRF2 pathway, omaveloxolone ameliorates oxidative stress and improves mitochondrial function. As a potent NRF2 activator, omaveloxolone exhibited significant liver toxicity with elevated AST/ALT levels in 37% of patients exposed to a dose of 150 mg.
  • Toxicity has also been reported with other potent NRF2 activators, such as bardoxolone methyl (EC50: 53 nM) which showed significant heart, liver, and renal toxicity in humans.

In contrast, our preclinical toxicological studies indicate that M102 has a much higher safety margin in relation to liver toxicity. M102 has the potential to modulate multiple key drivers of neurodegeneration, increasing the chances of achieving impactful neuroprotection and disease modifying effects in ALS.

This comprehensive package of preclinical efficacy data across two mouse models as well as patient-derived astrocyte toxicity assays, provides a strong rationale for clinical evaluation of M102 in ALS patients. Combined with the development of target engagement biomarkers and the completed preclinical toxicology package, a clear translational pathway to testing in ALS patients has been developed.”

https://molecularneurodegeneration.biomedcentral.com/articles/10.1186/s13024-025-00908-y “M102 activates both NRF2 and HSF1 transcription factor pathways and is neuroprotective in cell and animal models of amyotrophic lateral sclerosis”

Combining exercise with sulforaphane

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A 2025 clinical trial with old people compared NRF2 effects of acute exercise with pre- and post-exercise sulforaphane treatment:

“This study tested the hypothesis that combining acute exercise (in vivo stimulus) with ex vivo sulforaphane (SFN) treatment would induce greater NRF2 activation and signaling in older adults compared to either treatment alone. This approach was used to bypass the potential issue of inter-individual variability in metabolism and bioavailability of SFN supplementation through oral consumption and thereby provide more rigorous biological control to establish mechanistic feasibility.

Twenty-five older adults (12 men, 13 women; mean age: 67 ± 5 years) performed 30-min cycling exercise. Blood was drawn before and immediately after exercise to isolate peripheral blood mononuclear cells (PBMCs) and incubate with and without SFN (5 μM) treatment.

Acute exercise induced modest transcriptional changes across the four tested transcripts compared to the robust upregulation elicited by SFN. This disparity was notable given the comparable NRF2/ARE binding activity observed between EX and SFN.

Near-significant trends were observed for EX in heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), and glutathione reductase (GR) (after Bonferroni correction), while glutamate-cysteine ligase catalytic subunit (GCLC) was not induced by EX. In contrast, SFN alone robustly induced expression of NQO1, HO-1, GR, and GCLC.

We had chosen 5 μM as the dose based on pilot data from our laboratory and existing literature from in vitro experiments. However, typically, SFN is not combined with another stimulus.

To test this speculation, we ran a post hoc dose–response experiment where we stimulated PBMCs (n = 5) at six different SFN concentrations ranging from 0 to 20 μM (incubated for 5 h) and analyzed responses across the four genes used in the present study. The dose responses displayed hormetic curves for NQO1, GR, and GCLC, with 5 μM eliciting the peak response, suggesting that the lack of difference between SFN and the combined treatment was due to a ceiling effect of the SFN dose. Interestingly, HO-1 displayed a linear/curvilinear response with the maximal observed response at 20 μM.

In future ex vivo studies, a sulforaphane concentration of 1–2 μM in combination with acute exercise is predicted to enhance the expression of these antioxidant genes in the PBMCs of older adults to a greater extent than either treatment alone. Furthermore, lower SFN plasma concentrations are more likely to be achievable with oral supplementation.

To our knowledge, this is the first trial to measure responses to acute exercise combined with sulforaphane stimulation on NRF2 signaling in older men and women. We did not observe any statistically significant differences in any of our outcome variables between men and women.

Our results demonstrate that combining acute exercise with a sulforaphane stimulus elicits a greater response in nuclear NRF2 activity in older adults. While the response in gene expression did not completely mirror the response in NRF2 activation, it is important to note that NRF2 induces hundreds of cytoprotective genes. The four transcripts we measured are among those most commonly used to represent NRF2 signaling but do not capture the full picture. Full transcriptomics in future studies would address this question.”

https://link.springer.com/article/10.1007/s11357-025-01939-5 “Sulforaphane improves exercise-induced NRF2 signaling in older adults: an in vivo-ex vivo approach” (not freely available) Thanks to Dr. Tinna Traustadóttir for providing a copy.

I asked two questions, and will follow up with replies:

  1. Did a second experiment test effects of these subjects eating broccoli sprouts prior to acute exercise? The clinical trial’s NCT04848792 Study Overview section indicated that was the researchers’ intent.
  2. What studies have the data that produced this study’s graphical abstract’s younger vs. older NRF2 response graph?

Sulforaphane and malaria

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A 2025 rodent study investigated sulforaphane’s capability as an adjunct with standard treatment to inhibit resistant malaria strains:

“In this study, we performed proteomic analysis on a range of sensitive and artemisinin-resistant parasites, revealing specific dysregulation of PfK13 protein abundance. Reduced PfK13 levels were linked to impaired hemoglobin digestion, decreased free heme levels, and consequently, decreased artemisinin activation. Artemisinin resistant parasites also exhibited elevated thiol levels, indicating a more reduced cellular state.

Modulation of PfK13 levels or localisation modifies glutathione (GSH) levels, and elevated GSH decreases artemisinin potency. Elevated levels of reduced GSH and its precursor γ-glutamyl cysteine (gGlu-Cys) were observed in resistant parasites, while oxidised glutathione (GSSG) was lower.

In mammalian cells, SFN conjugates GSH, either passively or through the activity of glutathione-S-transferases, and the SFN-GSH conjugate causes oxidative stress. In response to this stress, Nrf2 translocates to the nucleus and interacts with the antioxidant response element (ARE) of target genes, resulting in expression of antioxidant genes, which induces an antioxidant response. However, P. falciparum has no identified Nrf2 orthologue and so likely lacks a KEAP1-Nrf2 mediated antioxidant response, which suggests that the SFN-GSH conjugate should only cause oxidative stress in parasites.

SFN has antioxidant properties for the host through activation of Nrf2. Therefore our molecule of choice would not only kill the parasite, but will boost the host antioxidant capacity. This differs from most other available pro-oxidants, which do not have this host antioxidant capacity.

5mg/kg SFN was found to be sufficient to significantly prolong the survival of artesunate-treated mice infected with parasites.

PfK13 mutations drive artemisinin resistance in Plasmodium parasites by enhancing antioxidant defences, which can be targeted by redox modulators such as sulforaphane. By leveraging SFN’s ability to induce oxidative stress and deplete thiol levels in parasites, this approach can enhance the efficacy of artemisinin and potentially restore its effectiveness against resistant strains.”

https://www.biorxiv.org/content/10.1101/2025.10.05.680568v1.full “PfK13-associated artemisinin resistance slows drug activation and enhances antioxidant defence, which can be overcome with sulforaphane”

Get a little stress into your life, Part 2

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A 2025 reply to a letter to the editor cited 56 references to elaborate on Part 1 and related topics:

“A positive effect does not necessarily mean benefit, and positive effects on individual organisms may mean adverse effects on other coexisting organisms. However, a vast literature shows that hormetic stimulation can result in benefits depending on the context, for instance, clear growth, yield, and survival improvement.

There is some energetic cost to support hormetic stimulation, with a likely positive energy budget, which might also have negative consequences if there is insufficient energy substrate, especially under concurrent severe environmental challenges. Moreover, hormetic preconditioning could be particularly costly when there is a mismatch between the predicted environment and the actual environment the same individuals or their offspring might face in the future.

Hormesis should not be unilaterally linked to positive and beneficial effects without considering dose levels. For any research to answer the question of whether a stimulation represents hormesis and whether it is beneficial, robust dose–response evaluations are needed, which should be designed a priori for this purpose, meeting the requirements of the proper number, increment, and range of doses.

Both additivity and synergism are possible in the hormetic stimulatory zone, depending also on the duration of exposure and the relative ratio of different components. This might happen, for example, when a chemical primes stress pathways (e.g., heat shock proteins and antioxidants), thus enabling another chemical to trigger hormesis (defense cross-activation) and/or because combined low subtoxicity may modulate receptors (e.g., aryl hydrocarbon receptor and nuclear factor erythroid 2-related factor 2) differently than individual exposures (receptor binding synergy).

Moreover, even when stimulation occurs in the presence of individual components, stimulation may no longer be present when combined, and therefore, effects of mixtures cannot be accurately predicted based on the effects of individual components. There may be hormesis trade-offs; hormesis should be judged based on fitness-critical end points.

While often modeled mathematically, hormesis is fundamentally a dynamic biological process and should not be seen as a purely mathematical function, certainly not a linear one. Much remains to be learned about the role of hormesis in global environmental change, and an open mind is needed to not miss the forest for the trees.”

https://pubs.acs.org/doi/10.1021/acs.est.5c05892 “Correspondence on ‘Hormesis as a Hidden Hand in Global Environmental Change?’ A Reply”

Reference 38 was a 2024 paper cited for:

“Hormetic-based interventions, particularly priming (or preconditioning), do not weaken organisms but strengthen them, enhancing their performance and health under different environmental challenges, which are often more massive than the priming exposure.

The catabolic aspect of hormesis is primarily protective whereas the anabolic aspect promotes growth, and their integration could optimize performance and health. The concept of preconditioning has also gained widespread attention in biomedical sciences.”

https://www.sciencedirect.com/science/article/abs/pii/S1568163724004069 “The catabolic – anabolic cycling hormesis model of health and resilience” (not freely available)

Reference 40 was a 2021 review that characterized hormesis as a hallmark of health:

“Health is usually defined as the absence of pathology. Here, we endeavor to define health as a compendium of organizational and dynamic features that maintain physiology.

Biological causes or hallmarks of health include features of:

  • Spatial compartmentalization (integrity of barriers and containment of local perturbations),
  • Maintenance of homeostasis over time (recycling and turnover, integration of circuitries, and rhythmic oscillations), and
  • An array of adequate responses to stress (homeostatic resilience, hormetic regulation, and repair and regeneration).

Disruption of any of these interlocked features is broadly pathogenic, causing an acute or progressive derailment of the system.

A future ‘medicine of health’ might detect perilous trajectories to intercept them by targeted interventions well before the traditional ‘medicine of disease’ comes into action.”

https://www.sciencedirect.com/science/article/pii/S0092867420316068 “Hallmarks of Health”

Betaine as an exercise mimetic

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A 2025 human study investigated effects of long-term exercise:

“Exercise has well-established health benefits, yet its molecular underpinnings remain incompletely understood. We conducted an integrated multi-omics analysis to compare effects of acute vs. long-term exercise in healthy males.

Acute exercise induced transient responses, whereas repeated exercise triggered adaptive changes, notably reducing cellular senescence and inflammation and enhancing betaine metabolism. Exercise-driven betaine enrichment, partly mediated by renal biosynthesis, exerts geroprotective effects and rescues age-related health decline in mice.

Betaine binds to and inhibits TANK-binding kinase 1 (TBK1), retarding the kinetics of aging.

Betaine effectively alleviated senescence phenotypes by reduced senescence-associated β-galactosidase (SA-β-Gal)-positive cells, decreased p21 expression, lowered DNA damage indicator γ-H2A.X, and elevated heterochromatin mark H3K9me3. Betaine treatment also enhanced cellular antioxidant capacity, as evidenced by increased NRF2 phosphorylation and reduced ROS accumulation.

These findings systematically elucidate the molecular benefits of exercise, and position betaine as an exercise mimetic for healthy aging.”

https://doi.org/10.1016/j.cell.2025.06.001 “Systematic profiling reveals betaine as an exercise mimetic for geroprotection” (not freely available) Thanks to Dr. Weimin Ci for providing a copy.

Stay away from NAC

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A 2025 rodent study added several reasons to avoid non-emergency use of N-acetylcysteine:

“We previously showed that antioxidants induced an impairment of negative feedback of the hypothalamus-pituitary-adrenal (HPA) axis in rats, in parallel to a down-regulation of glucocorticoid receptor (GR) and nuclear factor erythroid 2-related factor 2 (Nrf2) expression in the pituitary gland. This study evaluated the role of the Nrf2-heme-oxygenase-1 (HO-1) pathway on impairment of negative feedback of the HPA axis induced by N-acetylcysteine (NAC).

Male Swiss-Webster mice were orally supplemented with NAC for 5 consecutive days. The Nrf2-HO-1 pathway activator cobalt protoporphyrin IX (CoPPIX) was injected intraperitoneally on days 2 and 5 after starting NAC supplementation.

NAC reduced expression of Nrf2 in the pituitary of mice. NAC induced adrenal enlargement and hypercorticoidism, along with a decrease in GRα expression and an increase of GRβ expression in the pituitary gland.

We observed that dietary supplementation with NAC ( Figure 4A ) significantly increased plasma corticosterone levels in mice 24h ( Figure 4B ) as well as 15 days ( Figure 4C ) after the last administration of the antioxidant with the same magnitude of response (3.5-fold and 3.4-fold, respectively).

Chronic activation of the HPA axis can have damaging effects on immune, cardiovascular, metabolic, and neural functions, increasing the risk of immune system dysfunction, mood disorders, and metabolic and cardiovascular diseases. To prevent these deleterious effects of chronic hypercortisolism, HPA axis function is controlled by a glucocorticoid-dependent negative feedback system that is essential for ending the stress response.

These findings showed that NAC reduced Nrf2-HO-1 pathway activation in the pituitary gland, in a mechanism probably related to a local downregulation of GRα and an up-regulation of GRβ, leading to a failure of negative feedback of the HPA axis and consequently to the hyperactivity of this neuroendocrine axis.”

https://pmc.ncbi.nlm.nih.gov/articles/PMC11827418/ “Activation of the Nrf2/HO-1 pathway restores N-acetylcysteine-induced impairment of the hypothalamus-pituitary-adrenal axis negative feedback by up-regulating GRα expression and down-regulating GRβ expression into pituitary glands”

A human equivalent to this study’s NAC dose is (150 mg x .081) x 70 kg = 851 mg. Human supplements are sold in 600 mg and 1000 mg doses.

Grok 3 replied to a question: Human equivalent time to 15 days in male Swiss-Webster mice aged between 4 and 6 weeks? by stating: “15 days in male Swiss-Webster mice aged 4 to 6 weeks corresponds to approximately 4.1 human years, advancing their equivalent human age from about 10–12 years to roughly 14–16 years.” Four+ years seems like a long time for NAC to steadily and continuously affect humans’ HPA axes per the above graphic. What do you think?

Previously mentioned reasons to avoid daily use of NAC were in the lower part of A good activity for bad weather days.

Practice what you preach, or shut up

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A 2025 review subject was sulforaphane and brain health. This paper was the latest in a sequence where the retired lead author self-aggrandized his career by citing previous research.

He apparently doesn’t personally do what these research findings suggest people do. The lead author is a few weeks older than I am, and has completely white hair per an interview (Week 34 comments). I’ve had dark hair growing in (last week a barber said my dark hair was 90%) since Week 8 of eating broccoli sprouts every day, which is a side effect of ameliorating system-wide inflammation and oxidative stress.

If the lead author followed up with what his research investigated, he’d have dark hair, too. Unpigmented white hair and colored hair are both results of epigenetics.

Contrast this lack of personal follow-through of research findings with Dr. Goodenowe’s protocol where he compared extremely detailed personal brain measurements at 17 months and again at 31 months. He believes enough in his research findings to personally act on them, and demonstrate to others how personal agency can enhance a person’s life.

It’s every human’s choice whether or not we take responsibility for our own one precious life. I’ve read and curated on this blog many of this paper’s references. Five years ago for example:

So do more with their information than just read.

https://www.mdpi.com/2072-6643/17/8/1353 “Sulforaphane and Brain Health: From Pathways of Action to Effects on Specific Disorders”

2025 α-ketoglutarate research

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I haven’t mentioned α-ketoglutarate for a while, although I’ve taken it twice a day for several years. Here are four 2025 papers on α-ketoglutarate, starting with a review of its role in bone health:

“α-Ketoglutarate (α-KG) serves as a pivotal intermediate in various metabolic pathways in mammals, significantly contributing to cellular energy metabolism, amino acid metabolism, and other physiological processes. α-KG may be a therapeutic target for a variety of bone-related diseases, such as osteoporosis, osteoarthritis, and rheumatoid arthritis, because of its role in maintaining metabolic balance of bone.

α-KG, as a rate-determining mitochondrial intermediate, is crucial in cell energy metabolism because it connects intracellular carbon and nitrogen metabolism between isocitrate and succinyl coenzyme A. Additionally, α-KG is closely involved in the amino acid cycle. As a precursor of amino acids such as glutamine and glutamic acid, α-KG plays a direct role in energy production and a wide range of cellular chemical reactions. α-KG provides an energy source, stimulating protein synthesis, inhibiting protein degradation in muscle, and serving as a significant metabolic fuel for gastrointestinal cells.

α-KG promotes osteogenic differentiation of stem cells, increases activity of osteoblasts to promote osteogenesis, and inhibits bone resorption activity of osteoclasts. α-KG in articular cartilage promotes differentiation and maturation of chondrocytes and formation of a cartilage matrix. The protective effect of α-KG on bone has practical value in treatment of abnormal bone loss symptoms in various bone tissue diseases.”

https://www.sciengine.com/ABBS/doi/10.3724/abbs.2025020 “Essential role of the metabolite α-ketoglutarate in bone tissue and bone-related diseases”

A rodent study explored adding α-KG to osteoarthritis treatment:

“Mesenchymal stem cell (MSC) therapy represents a promising treatment strategy for osteoarthritis (OA). Nevertheless, the therapeutic efficacy of MSCs may be attenuated under conditions of cellular senescence or when the available clinical quantity is insufficient. α-Ketoglutarate (AKG) exerts beneficial effects on skeletal tissues and activity of stem cells. The present study was designed to explore the potential of AKG in augmenting viability of MSCs and the potential of their combined utilization in treatment of OA.

AKG plays a crucial role in multiple biological processes. It is involved in regulating stem cell differentiation, exerts anti-apoptotic effects, modulates the body’s immune and inflammatory responses, contributes to muscle and bone development, and is essential for maintaining stability of the cartilage matrix.

Platelet-rich plasma (PRP) has been demonstrated to have protective effects on chondrocytes and can effectively repair damaged cartilage in OA. However, PRP has intractable problems in terms of product quality control and allogeneic application, and its long-term therapeutic effect gradually weakens.

Combining AKG’s regulation of cellular metabolism with the multi-directional differentiation and immunomodulatory functions of MSCs is likely to generate a synergistic effect. This combined treatment modality targets the complex pathological processes of OA, including cartilage damage, inflammatory responses, and extracellular matrix imbalance, in a more comprehensive manner than a single therapy.”

https://www.sciencedirect.com/science/article/pii/S2707368825000032 “The repair effect of α-ketoglutarate combined with mesenchymal stem cells on osteoarthritis via the hedgehog protein pathway”

A rodent study investigated whether α-KG has a role in determining frailty:

“Frailty is an age-related geriatric syndrome, for which the mechanisms remain largely unknown. We performed a longitudinal study of aging female (n = 40) and male (n = 47) C57BL/6NIA mice, measured frailty index, and derived metabolomics data from plasma samples.

We find that frailty related metabolites are enriched for amino acid metabolism and metabolism of cofactors and vitamins, include ergothioneine, tryptophan, and alpha-ketoglutarate, and present sex dimorphism. We identify B vitamin metabolism related flavin adenine dinucleotide and pyridoxate as female-specific frailty biomarkers, and lipid metabolism related sphingomyelins, glycerophosphoethanolamine and glycerophosphocholine as male-specific frailty biomarkers.

We were interested to observe whether metabolite abundance at any specific timepoint was associated with frailty at a future timepoint. Unfortunately, we didn’t observe any metabolites that showed an overall significant association with future FI (FIf) or future devFI (devFIf). When focusing only on the abundance of metabolites at the baseline time point (∼400 days), we found a single metabolite, alpha-ketoglutarate, was negatively associated with both FIf and devFIf.”

https://www.biorxiv.org/content/10.1101/2025.01.22.634160v1.full “Metabolomics biomarkers of frailty: a longitudinal study of aging female and male mice”

Wrapping up with a rodent study adding α-KG to exercise for its effects on depression and learning:

“aKG acts as a prophylactic and antidepressant to effectively counteract social avoidance behaviors by modulating BDNF levels in the hippocampus and nucleus accumbens. Exercise increases aKG levels in the circulation.

In mice, aKG supplementation prolongs lifespan and reduces aging-associated frailty. aKG supplementation also reverses aging in humans as measured by DNA methylation patterns.

aKG functions as a co-factor for epigenetic enzymes. Changes in the intracellular αKG/succinate ratio regulates chromatin modifications, including H3K27me3 and ten-eleven translocation (Tet)-dependent DNA demethylation. The ability of aKG to influence epigenetic status of cells may explain both its prophylactic and anti-depressant effects since transcriptional dysregulation and aberrant epigenetic regulation are unifying themes in psychiatric disorders. This may also explain its ability to differentially regulate BDNF expression in the hippocampus and NAc.

If exercise mediates its effects through aKG, aKG may be a pivotal component of an exercise pill along with lactate and BHB that can serve as both a prophylactic and antidepressant treatment for depression.”

https://www.sciencedirect.com/science/article/pii/S266717432500031X “α-ketoglutarate (aKG) is a circulatory exercise factor that promotes learning and memory recall and has antidepressant properties

Coffee compound effects

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Three papers continue Polyphenol Nrf2 activators themes starting with a 2025 review of chlorogenic acid:

“Chlorogenic acid may comprise between 70 and 350 mg per cup of coffee. Chlorogenic acid can reduce reactive oxygen species (ROS) levels via the upregulation of antioxidant enzymes, decreasing oxidative stress/damage due to the action of adaptive hormetic mechanisms. There is also a substantial literature of hormetic dose responses for metabolites of chlorogenic acid, such as caffeic acid and ferulic acid.

Chlorogenic acid-induced hormetic biphasic dose responses in a spectrum of experimental designs:

  1. Responses to direct exposures in a range of cell types;
  2. Preconditioning experiments in which a prior dose of chlorogenic acid protected against a subsequent stressor agent;
  3. Studies that included direct exposure, showing hormesis dose responses and then selecting the optimal hormetic dosage as a preconditioning treatment to protect against a subsequent exposure to a toxic agent; and
  4. A mixed group of experiments in which preconditioning was conducted, including several neuronal cellular models, all showing protection against the subsequent exposure to the toxic agent.

However, in the context of translating experimental data to clinical relevance, the concentrations employed in the majority of the in vitro studies with chlorogenic acid far exceeded transitory peak levels, even in heavy coffee drinkers (i.e., approximately 3 μM). In addition to the use of unrealistically high chlorogenic acid concentrations, exposures were prolonged, ranging from 1 to 3 days. These studies are of limited relevance to humans, a similar concern raised by other researchers involved with polyphenol research.


The present paper has framed the hypothesis that key coffee constituents, such as chlorogenic acid, show hormetic effects in a range of cell types and endpoints. Chlorogenic acid may affect some of the health benefits of coffee drinking via its role in GI tract health and beneficial brain-gut interaction.”

https://www.sciencedirect.com/science/article/abs/pii/S0009279724004897 “Do the hormetic effects of chlorogenic acid mediate some of the beneficial effects of coffee?” (not freely available) Thanks to Dr. Evgenios Agathokleous for providing copies of this and the following paper.

A 2024 review by the same research group was on hormetic effects of caffeic acid:

“Caffeic acid is a polyphenol present in numerous fruits and vegetables, especially in coffee. Diets contain about 5–10 to 50 milligrams per day of caffeic acid while coffee ingestion provides about another 250–600 milligrams per day. For the moderate to heavy coffee drinker this would result in an ingestion of about 600–1000 milligrams of caffeic acid from food and coffee consumption.

The present paper evaluates whether caffeic acid may act as an hormetic agent, mediating its chemoprotective effects as has been shown for related agents, such as rosmarinic acid, ferulic acid, and chlorogenic acid. Caffeic acid protective effects were mediated via the upregulation of a series of antioxidant enzymes related to activation of Nrf2.

Caffeic acid enhanced the lifespan of C. elegans along with similar observations for rosmarinic acid that can be hydrolyzed to caffeic acid. Several hundred plant-based agents can enhance lifespan in experimental models such as C. elegans, and there is a competition to find the most effective agents with potential commercial applications.

Hormetic effects typically show a 30 to 60% stimulation above control. This is far below the 2 to 3-fold greater than control detection limit for statistical significance based on human variability/bioplasticity and are often reported as false negatives.

A weight-of-evidence approach was proposed based on multiple in vivo and in vitro test results to derive a study design strategy to increase detection of hormetic effects within the clinical trial framework. Such research should explore hormetic based interactions linking protective catabolic-based adaptive responses with activation and regulation of anabolic mediated hormetic growth effects.”

https://www.tandfonline.com/doi/full/10.1080/19390211.2024.2410776 “Caffeic Acid: Numerous Chemoprotective Effects are Mediated via Hormesis” (not freely available)

A 2024 review provided an overall picture of coffee compounds’ cardiometabolic effects:

“This review provides a comprehensive synthesis of longitudinal observational and interventional studies on the cardiometabolic effects of coffee consumption.

  • Findings indicate that while coffee may cause short-term increases in blood pressure, it does not contribute to long-term hypertension risk.
  • There is limited evidence indicating that coffee intake might reduce the risk of metabolic syndrome and non-alcoholic fatty liver disease.
  • Coffee consumption is consistently linked with reduced risks of type 2 diabetes (T2D) and chronic kidney disease (CKD), showing dose-response relationships.
  • The relationship between coffee and cardiovascular disease is complex, showing potential stroke prevention benefits but ambiguous effects on coronary heart disease.
  • Moderate coffee consumption, typically ranging from 1 to 5 cups per day, is linked to a reduced risk of heart failure, while its impact on atrial fibrillation remains inconclusive. Coffee consumption is associated with a lower risk of all-cause mortality, following a U-shaped pattern, with the largest risk reduction observed at moderate consumption levels.
  • Except for T2D and CKD, Mendelian randomization studies do not robustly support a causal link between coffee consumption and adverse cardiometabolic outcomes.

Potential beneficial effects of coffee on cardiometabolic health are consistent across age, sex, geographical regions, and coffee subtypes and are multi-dimensional, involving antioxidative, anti-inflammatory, lipid-modulating, insulin-sensitizing, and thermogenic effects. Based on its beneficial effects on cardiometabolic health and fundamental biological processes involved in aging, moderate coffee consumption has the potential to contribute to extending healthspan and increasing longevity.”

https://pmc.ncbi.nlm.nih.gov/articles/PMC11493900 “Coffee consumption and cardiometabolic health: a comprehensive review of the evidence”

Nrf2 regulation

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This 2025 review explored what’s known so far about Nrf2 post-translational regulators:

“Nrf2 is controlled at multiple levels, including epigenetic, transcriptional, translational, and post-translational. The focus of this review is on proteins that control Nrf2 at the post-translational level because in normal cells they are of preeminent importance.

We outline mechanisms by which multiple E3 ubiquitin ligases act to repress Nrf2 expression, how derepression of Nrf2 (and induction of its target genes) by oxidative stressors occurs, and why tissue injury and endoplasmic reticulum stress downregulate Nrf2. This update also explains how Nrf2 is embedded in thiol biochemistry, and outlines signaling pathways and endogenous signaling molecules that control its activity.

Nrf2 not only positively controls the basal and/or inducible expression of a substantial number of genes in all tissues but also downregulates many genes. Estimates of the number of antioxidant/electrophile-responsive element (ARE/EpRE)-driven genes that are positively regulated by Nrf2 vary from several hundred to >2000 depending on the experimental method, species, cell type, physiology, age, sex, diet, and the magnitude of the change that is deemed to be significant.

Induction of ARE/EpRE-driven genes allows adaptation to oxidative, electrophilic, and inflammatory stress. Nrf2 positively regulates clusters of genes encoding proteins classed broadly as antioxidant, drug-, heme-, and iron-metabolizing, pentose phosphate pathway, NADPH-generating, and autophagy-related, as well as fatty acid oxidation enzymes, lipases, transcription factors, and Keap1.

Genes that are negatively regulated by Nrf2 include those encoding the cytokines IL-1β and IL-6, myosin light-chain kinase (MYLK), and NADPH oxidase 4 (NOX4). Nrf2 also regulates some microRNAs, which represents another mechanism by which Nrf2 can downregulate the expression of genes such as those encoding collagens 1A2, 3A1, and 5A1, heat shock protein 47, fibronectin, and elastin. In addition, several lipogenesis-related genes such as fatty acid synthase 1 (FASN1) and acetyl-CoA carboxylase 1 (ACC1), stearoyl-CoA desaturase (SCD1), and fatty acid elongase 6 (ELOVL6) are downregulated upon Nrf2 activation, particularly under conditions of lipid overload. Given that lipogenesis is a highly NADPH-consuming process, it seems that Nrf2 activation redirects NADPH consumption from lipid synthesis towards redox reactions, although the mechanisms underlying the negative regulation of these genes are incompletely understood.

de novo synthesized Nrf2 upon Keap1 inactivation enables a rapid increase of levels of the transcription factor in response to metabolic changes and environmental challenges, allowing cells to adapt and restore homeostasis.”

https://www.cell.com/trends/biochemical-sciences/fulltext/S0968-0004(24)00282-2 “Regulating Nrf2 activity: ubiquitin ligases and signaling molecules in redox homeostasis”

This review’s primary audience is other researchers, and it ended with 15 outstanding items that Nrf2 research hasn’t yet adequately addressed.

Reversing hair greying, Part 2

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Three papers that cited the 2021 Reversing hair greying study, starting with a 2024 rodent study:

“External treatment with luteolin, but not that with hesperetin or diosmetin, alleviated hair graying in  model mice. Internal treatment with luteolin also mitigated hair graying.

Both treatments suppressed the increase in p16ink4a-positive cells in bulges [senescent keratinocyte stem cells (KSCs)]. Both treatments also suppressed decreases in expression levels of endothelins in KSCs and their receptor (Ednrb) in melanocyte stem cells (MSCs), and alleviated hair graying in mice.”

https://www.mdpi.com/2076-3921/13/12/1549 “Anti-Graying Effects of External and Internal Treatments with Luteolin on Hair in Model Mice”

This study treated subjects internally and externally with luteolin and hesperetin, which are ranked #7 (effective treatment) and #14 (not an effective treatment) per Nrf2 activator rankings. I wonder what these researchers would have found if they used the #1 ranked Nrf2 activator, sulforaphane.

A 2024 review managed to cover the Nrf2 activation subject without mentioning sulforaphane:

“Certain types of hair graying can be prevented or treated by enhancing MSC maintenance or melanocyte function, reducing oxidative stress, and managing secretion and action of stress hormones.

Tactical approaches to pursue this goal may include a selective activation of the p38 MAPK–MITF axis, enhancing cellular antioxidant capacity through activating NRF2, and modulating the norepinephrine–β2AR–PKA signaling pathway.”

https://www.mdpi.com/2076-3417/14/17/7450 “Intrinsic and Extrinsic Factors Associated with Hair Graying (Canities) and Therapeutic Potential of Plant Extracts and Phytochemicals”

This reviewer also avoided citing the 2021 Sulforaphane and hair loss, although hair loss was mentioned multiple times. I suspect that institutional politics was involved, as both papers are from South Korea.

Reference 32 of this review was a 2023 review that covered mainly unintentional hair greying reversal as a side effect noted when people had pharmaceutical treatments for various diseases:

“Hair graying is a common and visible sign of aging resulting from decreased or absence of melanogenesis. It has long been thought that reversal of gray hair on a large scale is rare. However, a recent study reported that individual gray hair darkening is a common phenomenon, suggesting the possibility of large-scale reversal of gray hair.

All these treatments rely on the presence of a sufficient population of active McSCs. Maintaining a healthy population of McSCs is also an urgent problem that needs to be addressed.”

https://www.ijbs.com/v19p4588.htm “Reversing Gray Hair: Inspiring the Development of New Therapies Through Research on Hair Pigmentation and Repigmentation Progress”

I published A hair color anecdote two months into eating broccoli sprouts every day when I first noticed dark hair growing in. Since it’s been over 4 years that I’ve continued eating broccoli sprouts daily, I think it’s alright to stop referring to my continuing reversal of hair greying as an anecdote.

But it was apparently too late to address hair loss, which started before I turned 30. So now you know what to do. 🙂

Polyphenol Nrf2 activators

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Two 2024 reviews by the same group that published Sulforaphane in the Goldilocks zone investigated dietary polyphenols’ effects as “hormetic nutrients”:

“Polyphenols display biphasic dose–response effects by activating at a low dose the Nrf2 pathway resulting in the upregulation of antioxidant vitagenes [see diagram]. We aimed to discuss hormetic nutrients, including polyphenols and/or probiotics, targeting the Nrf2 pathway and vitagenes for the development of promising neuroprotective and therapeutic strategies to suppress oxidative stress, inflammation and microbiota deregulation, and consequently improve cognitive performance and brain health.

antioxidants-13-00484-g001

Hormetic nutrition through polyphenols and/or probiotics targeting the antioxidant Nrf2 pathway and stress resilient vitagenes to inhibit oxidative stress and inflammatory pathways, as well as ferroptosis, could represent an effective therapy to manipulate alterations in the gut microbiome leading to brain dysfunction in order to prevent or slow the onset of major cognitive disorders. Notably, hormetic nutrients can stimulate the vagus nerve as a means of directly modulating microbiota-brain interactions for therapeutic purposes to mitigate or reverse the pathophysiological process, restoring gut and brain homeostasis, as reported by extensive preclinical and clinical studies.”

https://www.mdpi.com/2076-3921/13/4/484 “Hormetic Nutrition and Redox Regulation in Gut–Brain Axis Disorders”

I’m not onboard with this study’s probiotic assertions because most of the cited studies contained unacknowledged measurement errors. Measuring gut microbiota, Part 2 found:

“The fecal microbiome does not represent the overall composition of the gut microbiome. Despite significant roles of gut microbiome in various phenotypes and diseases of its host, causative microbes for such characteristics identified by one research fail to be reproduced in others.

Since fecal microbiome is a result of the gut microbiome rather than the representative microbiome of the GI tract of the host, there is a limitation in identifying causative intestinal microbes related to these phenotypes and diseases by studying fecal microbiome.”

These researchers also erroneously equated isothiocyanate sulforaphane’s Nrf2-activating mechanisms with polyphenols activating Nrf2.

This research group did better in clarifying polyphenols’ mechanisms in a review of hormetic dose-response effects of the polyphenol rosmarinic acid:

“This article evaluates whether rosmarinic acid may act as a hormetic agent, mediating its chemoprotective effects as has been shown for similar agents, such as caffeic acid, a derivative of rosmarinic acid.

Rosmarinic acid enhanced memory in institute of cancer research male mice in the Morris water maze (escape latency).

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Of importance in the evaluation of rosmarinic acid are its bioavailability, metabolism, and tissue distribution (including the capacity to affect and/or cross the BBB and its distribution and half-life within the brain). In the case of polyphenols, including rosmarinic acid, they are typically delivered at low doses in the diet and, in most instances, they do not escape first-pass metabolism, with the prominent chemical forms being conjugates of glucuronides and sulfates, with or without methylation.

These conjugated metabolites are chemically distinct from the parent compound, showing considerable differences in size, polarity, and ionic form. Their biological actions are quite different from the parent compound.

Bioavailability studies reveal that maximum concentrations in plasma typically do not exceed 1 µM following consumption of 10–100 mg of a single phenolic compound, with the maximum concentration occurring typically less than 2 h after ingestion, then dropping quickly thereafter. In the case of the in vitro studies assessed herein, and with few exceptions, most of the studies employed concentrations >10 µM with some studies involving concentrations in the several hundred µM range, with the duration of exposure typically in the range of 24–72 h, far longer duration than the very short time interval of a few minutes to several hours in human in vivo situations.

We strongly recommend that all experiments using in vitro models to study biological responses to dietary polyphenols use only physiologically relevant flavonoids and their conjugates at appropriate concentrations, provide evidence to support their use, and justify any conclusions generated. When authors fail to do this, referees and editors must act to ensure that data obtained in vitro are relevant to what might occur in vivo.”

https://www.degruyter.com/document/doi/10.1515/med-2024-1065/html “The chemoprotective hormetic effects of rosmarinic acid”

An elevator pitch for plasmalogen precursors

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An excerpt from the latest video at Dr. Goodenowe’s Health Matters podcast, Episode 7 “The Truth about Parkinson’s”, starting at 50:30:

“What’s exciting about this community medicine focus that we’ve switched to which basically says: How do we develop technologies in a way that they can be incorporated into a community model versus a pharmaceutical drug model? People can actually do I would say self-experiment just the way you self-experiment with your own diet because these are fundamentally dietary nutrition molecules.

Could you give me an elevator pitch because there are probably people listening who are thinking what is this plasmalogen precursor and for sure how is it having this dramatic effect?

Plasmalogens are the most important nutrient that nobody knows about. Normally you don’t know about it because the body is usually pretty good at making them. What makes plasmalogens unique is that your body makes them kind of like cannon fodder, the first group of people that go into war. Your body throws them out for destruction. They absorb oxidative stress and get destroyed in the process.

They’re stored in your cell membranes. 50% of the membranes of your heart are these plasmalogen molecules. When your heart gets inflamed, what your heart does is it dumps these plasmalogens out of its membranes to douse the flame of inflammation. After inflammation is under control, your body naturally builds these things back up again.

But if you have an inability to make enough plasmalogens, these inflammation events knock you down and keep you down. So plasmalogen precursors are critical for maintaining high levels of plasmalogens across your body, not just in your brain (30% of the lipids in your brain) but in your heart, your lungs, your kidneys.”

PXL_20241117_185248742~2