Hippocampus

Adverse epigenetic effects of prenatal and perinatal anesthesia

gettingwell4 4-5 stars Advanced knowledge, Brain development, Epigenetics, Hippocampus, Limbic system, Memory , , , , ,

This 2018 Chinese animal review subject was prenatal and perinatal anesthesia’s adverse epigenetic effects on a fetus/neonate:

“Accumulating evidence from rodent and primate studies has demonstrated that in utero or neonatal exposure to commonly used inhaled and intravenous general anesthetics is associated with neural degeneration and subsequent neurocognitive impairments, manifested in learning and memory disabilities.

So far, conflicting data exist about the effect of anesthetic agents on neurodevelopment in humans and no definite conclusion has been given yet.”

The inhibitors in the above graphic counter anesthesia’s effects on the fetus/neonate, summarized as:

“Epigenetic targeting of DNA methyltransferases and/or histone deacetylases may have some therapeutic value.”

Do physicians consider possible epigenetic alterations of a newborn’s chromatin structure and gene expression when they administer anesthesia to mothers during childbirth?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6079265/ “Epigenetic Alterations in Anesthesia-Induced Neurotoxicity in the Developing Brain”

The epigenetic clock now includes skin

gettingwell4 5+ stars Premium, Cerebellum, Cerebrum, Epigenetics, Hippocampus, Immune system, Limbic system, Lower brain, Telomeres , , , , , ,

The originator of the 2013 epigenetic clock improved its coverage with this 2018 UCLA human study:

“We present a new DNA methylation-based biomarker (based on 391 CpGs) that was developed to accurately measure the age of human fibroblasts, keratinocytes, buccal cells, endothelial cells, skin and blood samples. We also observe strong age correlations in sorted neurons, glia, brain, liver, and bone samples.

The skin & blood clock outperforms widely used existing biomarkers when it comes to accurately measuring the age of an individual based on DNA extracted from skin, dermis, epidermis, blood, saliva, buccal swabs, and endothelial cells. Thus, the biomarker can also be used for forensic and biomedical applications involving human specimens.

The biomarker applies to the entire age span starting from newborns, e.g. DNAm of cord blood samples correlates with gestational week.

Furthermore, the skin & blood clock confirms the effect of lifestyle and demographic variables on epigenetic aging. Essentially it highlights a significant trend of accelerated epigenetic aging with sub-clinical indicators of poor health.

Conversely, reduced aging rate is correlated with known health-improving features such as physical exercise, fish consumption, high carotenoid levels. As with the other age predictors, the skin & blood clock is also able to predict time to death.

Collectively, these features show that while the skin & blood clock is clearly superior in its performance on skin cells, it crucially retained all the other features that are common to other existing age estimators.”

http://www.aging-us.com/article/101508/text “Epigenetic clock for skin and blood cells applied to Hutchinson Gilford Progeria Syndrome and ex vivo studies”

An introduction to the study highlighted several items:

“Although the skin-blood clock was derived from significantly less samples (~900) than Horvath’s clock (~8000 samples), it was found to more accurately predict chronological age, not only across fibroblasts and skin, but also across blood, buccal and saliva tissue. A potential factor driving this improved accuracy in blood could be related to the approximate 18-fold increase in genomic coverage afforded by using Illumina 450k/850k beadarrays.

It serves as a roadmap for future clock studies, pointing towards the importance of constructing tissue or cell-type specific epigenetic clocks, to more accurately measure biological aging in the given tissue/cell-type, and therefore with the potential to be more informative of disease-risk or the success of disease interventions in the tissue or cell-type of interest.”

http://www.aging-us.com/article/101533/text “Epigenetic clocks galore: a new improved clock predicts age-acceleration in Hutchinson Gilford Progeria Syndrome patients”

The role of recall neurons in traumatic memories

gettingwell4 2-3 stars Required further work, Amygdala, Cerebrum, Epigenetics, Glutamate, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Primal Therapy, Stress , , , , , ,

This 2018 Swiss rodent study found:

“Our data show that:

  • A subset of memory recall–induced neurons in the DG [dentate gyrus] becomes reactivated after memory attenuation,
  • The degree of fear reduction positively correlates with this reactivation, and
  • The continued activity of memory recall–induced neurons is critical for remote fear memory attenuation.

Although other brain areas such as the prefrontal cortex and the amygdala are likely to be implicated in remote fear memories and remain to be investigated, these results suggest that fear attenuation at least partially occurs in memory recall–induced ensembles through updating or unlearning of the original memory trace of fear.

These data thereby provide the first evidence at an engram-specific level that fear attenuation may not be driven only by extinction learning, that is, by an inhibitory memory trace different from the original fear trace.

Rather, our findings indicate that during remote fear memory attenuation both mechanisms likely coexist, albeit with the importance of the continued activity of memory recall–induced neurons experimentally documented herein. Such activity may not only represent the capacity for a valence change in DG engram cells but also be a prerequisite for memory reconsolidation, namely, an opportunity for learning inside the original memory trace.

As such, this activity likely constitutes a physiological correlate sine qua non for effective exposure therapies against traumatic memories in humans: the engagement, rather than the suppression, of the original trauma.”

The researchers also provided examples of human trauma:

“We dedicate this work to O.K.’s father, Mohamed Salah El-Dien, and J.G.’s mother, Wilma, who both sadly passed away during its completion.”

So, how can this study help humans? The study had disclosed and undisclosed limitations:

1. Humans aren’t lab rats. We can ourselves individually change our responses to experiential causes of ongoing adverse effects. Standard methodologies can only apply external treatments.

2. It’s a bridge too far to go from neural activity in transgenic mice to expressing unfounded opinions on:

“A physiological correlate sine qua non for effective exposure therapies against traumatic memories in humans.”

Human exposure therapies have many drawbacks, in addition to being applied externally to the patient on someone else’s schedule. A few others were discussed in The role of DNMT3a in fear memories:

  • “Inability to generalize its efficacy over time,
  • Potential return of adverse memory in the new/novel contexts,
  • Context-dependent nature of extinction which is widely viewed as the biological basis of exposure therapy.”

3. Rodent neural activity also doesn’t elevate recall to become an important goal of effective human therapies. Clearly, what the rodents experienced should have been translated into human reliving/re-experiencing, not recall! Terminology used in animal studies preferentially has the same meaning with humans, since the purpose of animal studies is to help humans.

4. The researchers acknowledged that:

“Other brain areas such as the prefrontal cortex and the amygdala are likely to be implicated in remote fear memories and remain to be investigated.”

A study that provided evidence for basic principles of Primal Therapy determined another brain area:

“The findings imply that in response to traumatic stress, some individuals, instead of activating the glutamate system to store memories, activate the extra-synaptic GABA system and form inaccessible traumatic memories.”

The study I curated yesterday, Organ epigenetic memory, demonstrated organ memory storage. It’s hard to completely rule out that other body areas may also store traumatic memories.

The wide range of epigenetic memory storage vehicles is one reason why effective human therapies need to address the whole person, the whole body, and each individual’s entire history.

http://science.sciencemag.org/content/360/6394/1239 “Reactivation of recall-induced neurons contributes to remote fear memory attenuation” (not freely available)

Here’s one of the researchers’ outline:

This post has somehow become a target for spammers, and I’ve disabled comments. Readers can comment on other posts and indicate that they want their comment to apply here, and I’ll re-enable comments.

Flawed epigenetic measurements of behavioral experiences

gettingwell4 0-1 star Wasted resources, Cerebrum, Epigenetics, Hippocampus, Limbic system, Stress , , , ,

This 2018 New York rodent study not only wasted resources but also speciously attempted to extrapolate animal study findings to humans:

“While it is clear that behavioral experience modulates epigenetic profiles, it is less evident how the nature of that experience influences outcomes and whether epigenetic/genetic “biomarkers” could be extracted to classify different types of behavioral experience.

Male and female mice were subjected to either:

  • a Fixed Interval (FI) schedule of food reward, or
  • a single episode of forced swim followed by restraint stress, or
  • no explicit behavioral experience

after which global expression levels of two activating (H3K9ac and H3K4me3) and two repressive (H3K9me2 and H3k27me3) post-translational histone modifications (PTHMs), were measured in hippocampus (HIPP) and frontal cortex (FC).

A random subset of 5 of the 12 animals from each sex/behavioral experience group were used for these analyses. FC and HIPP were dissected from each of those 5 brains and homogenized for subsequent analyses. Thus, sample size for PTHM expression levels was n = 5 for each region/sex/behavioral treatment group and all PTHM expression level analyses utilized the homogenized tissue.

The specific nature of the behavioral experience differentiated profiles of PTHMs in a sex- and brain region-dependent manner, with all 4 PTHMs changing in parallel in response to different behavioral experiences. Global PTHMs may provide a higher-order pattern recognition function.”

The researchers knew or should have known that measuring “global expression levels” in “homogenized tissue” of “n = 5” subjects was flawed, and they did it anyway. They acknowledged some of the numerous study design defects with qualifiers such as:

“Even though these were global levels of histone modifications (and thus not indicative of changes at specific genes or sites on genes)..

As FS-RS behavioral experience was completed before FI behavioral experience, a longer overall post-behavior experience time (approximately 1 week) elapsed for this group, resulting in some differences in overall timing between these experiences and global PTHM assessment. However, extending the duration of the FS-RS experience (i.e., repeated exposures) would also have led to habituation..”

Did they purposely make these mistakes because of the “biomarkers” paradigm?

What would they have found if they had followed their judgments and training to design a better study? Experience-dependent histone modifications that differed by gender and brain region was certainly a promising research opportunity.

As for extrapolating the cited animal study findings to humans? Ummm..NO!

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060276/ “Different Behavioral Experiences Produce Distinctive Parallel Changes in, and Correlate With, Frontal Cortex and Hippocampal Global Post-translational Histone Levels”

Prenatal programming of human HPA axis development

gettingwell4 2-3 stars Required further work, Amygdala, Brain development, Brainstem, Cerebrum, Cortisol, Epigenetics, Hippocampus, Hypothalamus, Immune system, Limbic system, Locus coeruleus, Lower brain, Memory, Neurochemicals, Stress, Vasopressin , , , , , ,

This 2017 UC Irvine human review subject provided details of how fetal hypothalamic-pituitary-adrenal components and systems develop, and how they are epigenetically changed by the mother’s environment:

“The developmental origins of disease or fetal programming model predicts that intrauterine exposures have life-long consequences for physical and psychological health. Prenatal programming of the fetal hypothalamic-pituitary-adrenal (HPA) axis is proposed as a primary mechanism by which early experiences are linked to later disease risk.

Development of the fetal HPA axis is determined by an intricately timed cascade of endocrine events during gestation and is regulated by an integrated maternal-placental-fetal steroidogenic unit. Mechanisms by which stress-induced elevations in hormones of maternal, fetal, or placental origin influence the structure and function of the emerging fetal HPA axis are discussed.

Human gestational physiology and fetal HPA axis development differ even from that of closely related nonhuman primates, thereby limiting the generalizability of animal models. This review will focus solely on studies of prenatal stress and fetal HPA axis development in humans.”

1. Every time I read a prenatal study I’m in awe of all that has to go right – and at the appropriate times and sequences – for a fetus to be undamaged. Add in what needs to happen at birth, during infancy, and throughout early childhood, and it seems impossible for any human to escape epigenetic damage.

2. The reviewers referenced animal studies and human research performed with postnatal subjects, despite the disclaimer:

This review will focus solely on studies of prenatal stress and fetal HPA axis development in humans.”

This led to blurring of what had been studied or not with human fetuses regarding the subject.

3. These reviewers uncritically listed many dubious human studies that had both stated and undisclosed severe limitations on their findings. Other reviewers offer informed analysis of cited studies, as Sex-specific impacts of childhood trauma summarized with cortisol:

“Findings are dependent upon variance in extenuating factors, including but not limited to, different measurements of:

  • early adversity,
  • age of onset,
  • basal cortisol levels, as well as
  • trauma forms and subtypes, and
  • presence and severity of psychopathology symptomology.”

4. The paper would have been better had it stayed on topic with its title “Developmental origins of the human hypothalamic-pituitary-adrenal axis.” Let other reviews cover animals, post-natal humans, and questionable evidence.

5. I asked the reviewers to provide a searchable file to facilitate using their work as a reference.

https://www.researchgate.net/publication/318469661_Developmental_origins_of_the_human_hypothalamic-pituitary-adrenal_axis “Developmental origins of the human hypothalamic-pituitary-adrenal axis” (registration required)

Going off the rails with the biomarker paradigm

gettingwell4 < 0 Detracted from science, Acetylcholine, Dopamine, Epigenetics, Hippocampus, Limbic system, Memory, Neurochemicals , , , ,

This 2018 US government rodent study used extreme dosages to achieve its directed goals of demonizing nicotine and extolling the biomarker paradigm:

“This study examined whether adolescent nicotine exposure alters adult hippocampus-dependent learning, involving persistent changes in hippocampal DNA methylation and if choline, a dietary methyl donor, would reverse and mitigate these alterations.

Mice were chronically treated with nicotine (12.6mg/kg/day) starting at post-natal day 23 (pre-adolescent), p38 (late adolescent), or p54 (adult) for 12 days followed by a 30-day period during which they consumed either standard chow or chow supplemented with choline (9g/kg).

Our gene expression analyses support this model and point to two particular genes involved in chromatin remodeling, Smarca2 and Bahcc1. Both Smarca2 and Bahcc1 showed a similar inverse correlation pattern between promoter methylation and gene expression.

Our findings support a role for epigenetic modification of hippocampal chromatin remodeling genes in long-term learning deficits induced by adolescent nicotine and their amelioration by dietary choline supplementation.”

Let’s use the average weight of a US adult male – published by the US Centers for Disease Control as 88.8 kg – to compare the study’s dosages with human equivalents:

  1. Nicotine at ((“12.6mg/kg/day” x .081) x 88.8 kg) = 90.6 mg.
  2. Choline at ((“9g/kg” x .081) x 88.8 kg) = 65 g. The US National Institutes of Health published the Tolerable Upper Intake Levels for Choline as 3.5 g!!

Neither of these dosages are even remotely connected to human realities:

  1. The human-equivalent dosage of nicotine used in this study would probably kill an adult human before the end of 12 days.
  2. What effects would an adult human suffer from exceeding the choline “Tolerable Upper Intake Level” BY 18 TIMES for 30 days?

Isn’t the main purpose of animal studies to help humans? What’s the justification for performing animal studies simply to promote an agenda?

A funding source of this study was National Institute on Drug Abuse (NIDA) Identification of Biomarkers for Nicotine Addiction award (T-DA-1002 MG). Has the biomarker paradigm been institutionalized to the point where research proposals that don’t have biomarkers as goals aren’t funded?

https://www.sciencedirect.com/science/article/pii/S107474271830193X “Choline ameliorates adult learning deficits and reverses epigenetic modification of chromatin remodeling factors related to adolescent nicotine exposure” (not freely available)

How do memories transfer?

gettingwell4 2-3 stars Required further work, Acetylcholine, Brainstem, Cerebellum, Cerebrum, Hippocampus, Limbic system, Locus coeruleus, Lower brain, Memory, Neurochemicals, Thalamus , , , ,

This 2018 Chinese study electronically modeled the brain’s circuits to evaluate memory transfer mechanisms:

“During non-rapid-eye-movement (NREM) sleep, thalamo-cortical spindles and hippocampal sharp wave-ripples have been implicated in declarative memory consolidation. Evidence suggests that long-term memory consolidation is coordinated by the generation of:

  • Hierarchically nested hippocampal ripples (100-250 Hz),
  • Thalamo-cortical spindles (7-15 Hz), and
  • Cortical slow oscillations (<1 Hz)

enabling memory transfer from the hippocampus to the cortex.

Consolidation has also been demonstrated in other brain tasks, such as:

  • In the acquisition of motor skills, where there is a shift from activity in prefrontal cortex to premotor, posterior parietal, and cerebellar structures; and
  • In the transfer of conscious to unconscious tasks, where activity in initial unskilled tasks and activity in skilled performance are located in different regions, the so-called ‘scaffolding-storage’ framework.

By separating a neural circuit into a feedforward chain of gating populations and a second chain coupled to the gating chain (graded chain), graded information (i.e. information encoded in firing rate amplitudes) may be faithfully propagated and processed as it flows through the circuit. The neural populations in the gating chain generate pulses, which push populations in the graded chain above threshold, thus allowing information to flow in the graded chain.

In this paper, we will describe how a set of previously learned synapses may in turn be copied to another module with a pulse-gated transmission paradigm that operates internally to the circuit and is independent of the learning process.”

The study had neither been peer-reviewed, nor were the mechanisms tested in living beings.

https://www.biorxiv.org/content/early/2018/07/27/351114 “A Mechanism for Synaptic Copy between Neural Circuits”

Hidden hypotheses of epigenetic studies

gettingwell4 0-1 star Wasted resources, Amygdala, Brain development, Cerebellum, Cerebrum, Epigenetics, Hippocampus, Immune system, Limbic system, Lower brain, Stress , , , ,

This 2018 UK review discussed three pre-existing conditions of epigenetic genome-wide association studies:

“Genome-wide technology has facilitated epigenome-wide association studies (EWAS), permitting ‘hypothesis-free’ examinations in relation to adversity and/or mental health problems. Results of EWAS are in fact conditional on several a priori hypotheses:

  1. EWAS coverage is sufficient for complex psychiatric problems;
  2. Peripheral tissue is meaningful for mental health problems; and
  3. The assumption that biology can be informative to the phenotype.

1. CpG sites were chosen as potentially biologically informative based on consultation with a consortium of DNA methylation experts. Selection was, in part, based on data from a number of phenotypes (some medical in nature such as cancer), and thus is not specifically targeted to brain-based, stress-related complex mental health phenotypes.

2. The assumption is often that distinct peripheral tissues are interchangeable and equally suited for biomarker detection, when in fact it is highly probable that peripheral tissues themselves correspond differently to environmental adversity and/or disease state.

3. Analyses result in general statements such as ‘neurodevelopment’ or the ‘immune system’ being involved in the aetiology of a given phenotype. Whether these broad categories play indeed a substantial role in the aetiology of the mental health problem is often hard to determine given the post hoc nature of the interpretation.”

The reviewers mentioned in item #2 the statistical flaw of assuming that measured entities are interchangeable with one another. They didn’t mention that the problem also affected item #1 methodologies of averaging CpG methylation measurements in fixed genomic bins or over defined genomic regions, as discussed in:

The reviewers offered suggestions for reducing the impacts of these three hypotheses. But will doing more of the same, only better, advance science?

Was it too much to ask of researchers whose paychecks and reputations depended on a framework’s paradigm – such as the “biomarker” mentioned a dozen and a half times – to admit the uselessness of gathering data when the framework in which the data operated wasn’t viable? They already knew or should have known this.

Changing an individual’s future behavior even before they’re born provided one example of what the GWAS/EWAS framework missed:

“When phenotypic variation results from alleles that modify phenotypic variance rather than the mean, this link between genotype and phenotype will not be detected.”

DNA methylation and childhood adversity concluded that:

“Blood-based EWAS may yield limited information relating to underlying pathological processes for disorders where brain is the primary tissue of interest.”

The truth about complex traits and GWAS added another example of how this framework and many of its paradigms haven’t produced effective explanations of “the aetiology of the mental health problem”

“The most investigated candidate gene hypotheses of schizophrenia are not well supported by genome-wide association studies, and it is likely that this will be the case for other complex traits as well.”

Researchers need to reevaluate their framework if they want to make a difference in their fields. Recasting GWAS as EWAS won’t make it more effective.

https://www.sciencedirect.com/science/article/pii/S2352250X18300940 “Hidden hypotheses in ‘hypothesis-free’ genome-wide epigenetic associations”

A mid-year selection of epigenetic topics

gettingwell4 4-5 stars Advanced knowledge, Acetylcholine, Amygdala, Anterior cingulate cortex, Beliefs, Brain development, Brainstem, Cerebellum, Cerebrum, Cortisol, Dopamine, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Immune system, Limbic system, Lower brain, Memory, Neurochemicals, Primal Therapy, Serotonin, Stress, Telomeres, Testosterone, Vasopressin , , , , , , , , , , , , , , , , , ,

Here are the most popular of the 65 posts I’ve made so far in 2018, starting from the earliest:

The pain societies instill into children

DNA methylation and childhood adversity

Epigenetic mechanisms of muscle memory

Sex-specific impacts of childhood trauma

Sleep and adult brain neurogenesis

This dietary supplement is better for depression symptoms than placebo

The epigenetic clock theory of aging

A flying human tethered to a monkey

Immune memory in the brain

The lack of oxygen’s epigenetic effects on a fetus

The hypothalamus and aging

gettingwell4 2-3 stars Required further work, Brain development, Epigenetics, Hippocampus, Hypothalamus, Limbic system, Memory, Neurochemicals, Thalamus, Vasopressin , , , ,

This 2018 Korean review discussed aspects of the hypothalamus and aging:

“A majority of physiological functions that decline with aging are broadly governed by the hypothalamus, a brain region controlling development, metabolism, reproduction, circadian rhythm, and homeostasis. In addition, the hypothalamus is poised to connect the brain and the body so that the environmental information affecting aging can be transmitted through the hypothalamus to affect the systematic aging of the peripheral organs.

The hypothalamus is hypothesized to be a primary regulator of the process of aging of the entire body. This review aims to assess the contribution of hypothalamic aging to the age-related decline in body functions, particularly from the perspective of:

  • energy homeostasis,
  • hormonal balance,
  • circadian rhythm, and
  • reproduction,

and to highlight its underlying cellular mechanisms with a focus on:

  • nutrient sensing
  • inflammation,
  • loss of stem cell,
  • loss of proteostasis, and
  • epigenetic alterations.”

https://www.sciencedirect.com/science/article/pii/S0047637418300502 “Role of hypothalamus in aging and its underlying cellular mechanisms” (not freely available)

The reviewers didn’t consider aging to be an “unintended consequence” of development. This perspective was found in a reference to A study of DNA methylation and age:

“Aging is not programmed. Instead, aging is a continuation of developmental growth, driven by genetic pathways.

Genetic programs determine developmental growth and the onset of reproduction. When these programs are completed, they are not switched off.

Aging has no purpose (neither for individuals nor for group), no intention. Nature does not select for quasi-programs. It selects for robust developmental growth.”

The epigenetic clock theory of aging cited the same author, and modified his point to say:

“The proposed epigenetic clock theory of ageing views biological ageing as an unintended consequence of both developmental programmes and maintenance programmes.”

The current review’s opposite paradigm was:

“The hypothalamus is hypothesized to be a primary regulator of the process of aging.”

Almost all of the details discussed were from rodent studies.

As detailed in How to cure the ultimate causes of migraines? and its references, the hypothalamus is a brain structure that lacks feedback mechanisms for several of its activities. This structure develops shortly after conception and has an active prenatal role.

The hypothalamus plays its part in getting us developed and ready to reproduce, with certain feedback loops being evolutionarily unnecessary. The hypothalamus perfectly illustrates the point of:

“When these programs are completed, they are not switched off.”

Evolutionarily unnecessary feedback for aspects of hypothalamic activity may result in it not winding down when its developmental role is over. This activity shouldn’t be interpreted to construe a role that has some other meaning or purpose.

See Reevaluate findings in another paradigm for another view.

The lack of oxygen’s epigenetic effects on a fetus

gettingwell4 0-1 star Wasted resources, Acetylcholine, Amygdala, Brain development, Brainstem, Cerebellum, Cerebrum, Cortisol, Dopamine, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Limbic system, Lower brain, Memory, Neurochemicals, Serotonin, Stress, Vasopressin , , , , , , , , ,

This 2018 Loma Linda review subject was gestational hypoxia:

“Of all the stresses to which the fetus and newborn infant are subjected, perhaps the most important and clinically relevant is that of hypoxia. This review explores the impact of gestational hypoxia on maternal health and fetal development, and epigenetic mechanisms of developmental plasticity with emphasis on the uteroplacental circulation, heart development, cerebral circulation, pulmonary development, and the hypothalamic-pituitary-adrenal axis and adipose tissue.

An understanding of the specific hypoxia-induced environmental and epigenetic adaptations linked to specific organ systems will enhance the development of target-specific inhibition of DNA methylation, histone modifications, and noncoding RNAs that underlie hypoxia-induced phenotypic programming of disease vulnerability later in life.

A potential stumbling block to these efforts, however, relates to timing of the intervention. The greatest potential effect would be accomplished at the critical period in development for which the genomic plasticity is at its peak, thus ameliorating the influence of hypoxia or other stressors.

With future developments, it may even become possible to intervene before conception, before the genetic determinants of the risk of developing programmed disease are established.”

Table 3 “Antenatal hypoxia and developmental plasticity” column titles were Species | Offspring Phenotypes of Disorders and Diseases | Reference Nos.

Hypoxia phenotypes

This review was really an ebook, with 94 pages and 1,172 citations in the pdf file. As I did with Faith-tainted epigenetics, I read it with caution toward recognizing 1) the influence of the sponsor’s biases, 2) any directed narrative that ignored evidence contradicting the narrative, and 3) any storytelling.

Can you match the meaning of the review’s last sentence (“intervene before conception” quoted above) with the meaning of any sentence in its cited reference Developmental origins of noncommunicable disease: population and public health implications? I can’t.

One review topic that was misconstrued was transgenerational epigenetic inheritance of hypoxic effects. The “transgenerational” term was used inappropriately by several of the citations, and no cited study provided evidence for gestational hypoxic effects through the F3 great-grandchild generation.

One omitted topic was gestational hypoxic effects of caffeine. The first paper that came up for my PubMed search of “caffeine pregnancy hypoxia” was an outstanding 2017 Florida rodent review Long-term consequences of disrupting adenosine signaling during embryonic development that had this paragraph and figure:

“One substance that fetuses are frequently exposed to is caffeine, which is a non-selective adenosine receptor antagonist. We discovered that in utero alteration in adenosine action leads to adverse effects on embryonic and adult murine hearts. We find that cardiac A1ARs [a type of adenosine receptor] protect the embryo from in utero hypoxic stress, a condition that causes an increase in adenosine levels. 

After birth in mice, we observed that in utero caffeine exposure leads to abnormal cardiac function and morphology in adults, including an impaired response to β-adrenergic stimulation. Recently, we observed that in utero caffeine exposure induces transgenerational effects on cardiac morphology, function, and gene expression.”

The timing of in utero caffeine treatment leads to differences in adult cardiac function, gene expression, and phenotype. Exposure to caffeine from E6.5–9.5 leads the F1 generation to develop dilated cardiomyopathy with decrease % FS and increased Myh7 expression. In utero caffeine exposure from E10.5–13.5 leads to a hypertrophic cardiomyopathy in the F2 generation along with increased % FS and decreased Myh7 expression

Why was this review and its studies omitted? It was on target for both gestational hypoxia and transgenerational epigenetic inheritance of hypoxic effects!

It was alright to review smoking, cocaine, methamphetamine, etc., but the most prevalent drug addiction – caffeine – couldn’t be a review topic?

The Loma Linda review covered a lot, but I had a quick trigger due to the sponsor’s bias. I started to lose “faith” in the reviewers after reading the citation for the review’s last sentence that didn’t support the statement.

My “faith” disappeared after not understanding why a few topics were misconstrued and omitted. Why do researchers and sponsors ignore, misrepresent, and not continue experiments through the F3 generation to produce evidence for and against transgenerational epigenetic inheritance? Where was the will to follow evidence trails regardless of socially acceptable beverage norms?

The review acquired the taint of storytelling with the reviewers’ assertion:

“..timing of the intervention. The greatest potential effect would be accomplished at the critical period in development for which the genomic plasticity is at its peak, thus ameliorating the influence of hypoxia or other stressors.”

Contradictory evidence was in the omitted caffeine study’s graphic above which described two gestational critical periods where an “intervention” had opposite effects, all of which were harmful to the current fetus’ development and/or to following generations. Widening the PubMed link’s search parameters to “caffeine hypoxia” and “caffeine pregnancy” returned links to human early life studies that used caffeine in interventions, ignoring possible adverse effects on future generations.

This is my final curation of any paper sponsored by this institution.

https://www.physiology.org/doi/abs/10.1152/physrev.00043.2017 “Gestational Hypoxia and Developmental Plasticity” (not freely available) Thanks to coauthor Dr. Xiang-Qun Hu for providing a copy.

A self-referencing study of transgenerational epigenetic inheritance

gettingwell4 2-3 stars Required further work, Amygdala, Epigenetics, Hippocampus, Limbic system, Memory, Stress , ,

This 2018 Washington rodent study subject was transgenerational epigenetic inheritance of disease caused by a fungicide that’s been phased out or banned for over a decade:

“This study was designed to help understand how three different epigenetic processes in sperm are correlated with vinclozolin-induced epigenetic transgenerational inheritance of disease.

  1. Most DMRs [differential DNA-methylated regions] identified in this study are unique between the F1, F2, and F3 generations.
  2. The number of lncRNA was much higher than the number of sncRNA [small noncoding RNA, including microRNA]. The overlap between each generation was very low or nonexistent.
  3. The F1 and the F2 generation control versus vinclozolin lineage sperm had negligible DHRs [differential histone retention sites]. This observation suggests that the direct vinclozolin exposure does not alter histone retention or trigger any changes. However, the F3 generation control versus vinclozolin lineage sperm DHRs increased considerably.

It appears that the phenomenon is more complex than just a direct exposure triggering the formation of epimutations that are then simply maintained in the subsequent generations.”

There’s something odd about a study where a third of the 87 cited references list one of the study’s coauthors, who also coauthored A review of epigenetic transgenerational inheritance of reproductive disease. I couldn’t find a satisfactory explanation for the study’s over-the-top self-referencing.

What do you think?

I asked the coauthors why a third of the cited references were self-referencing. The lead author replied:

“The field in epigenetic transgenerational inheritance is expanding, however it is still hard for us to find relevant studies in rodents or human that we can cite. Most of the time DNA methylation, ncRNA and histone modifications are investigated from a direct exposure and/or from a purely mechanistic angle (e.g. DNA methylation of specific genes).

In contrast, transgenerational phenotypes and toxicology by definition excludes direct exposure and must be transmitted through multiple generations (the F3 generation is the first transgenerational one). We are not looking at specific genes but using whole genome sequencing technologies which is a broader approach.

Besides, if you do a pubmed search with the keywords “epigenetics” and “transgenerational”, you will probably find that more than 50% of the studies have been done by Dr Michael K. Skinner. He is also one of the first researcher who started to work on the epigenetic transgenerational inheritance phenomenon 15 years ago. Not citing his previous work is challenging.

We hope to see other labs contributing to this particular field and we will be delighted to cite them. In the meantime, our only option is to reference our previous work.”

I replied:

“Thank you for your reply! It must be exasperating to see other researchers stop their studies short of the F3 generation for no apparent or disclosed reason.

Have you seen even one scientifically adequate human study of transgenerational epigenetic inheritance?”

https://academic.oup.com/eep/article/4/2/dvy010/4987173 “Alterations in sperm DNA methylation, non-coding RNA expression, and histone retention mediate vinclozolin-induced epigenetic transgenerational inheritance of disease”

Resiliency in stress responses

gettingwell4 < 0 Detracted from science, Amygdala, Anterior cingulate cortex, Beliefs, Brain development, Brainstem, Cerebrum, Cortisol, Dopamine, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Limbic system, Locus coeruleus, Lower brain, Memory, Neurochemicals, Oxytocin, Primal Therapy, Serotonin, Stress, Thalamus , , , , , , , , ,

This 2018 US Veterans Administration review subject was resiliency and stress responses:

“Neurobiological and behavioral responses to stress are highly variable. Exposure to a similar stressor can lead to heterogeneous outcomes — manifesting psychopathology in one individual, but having minimal effect, or even enhancing resilience, in another.

We highlight aspects of stress response modulation related to early life development and epigenetics, selected neurobiological and neurochemical systems, and a number of emotional, cognitive, psychosocial, and behavioral factors important in resilience.”

The review cited studies I’ve previously curated:

There were two things I didn’t understand about this review. The first was why the paper isn’t freely available. It’s completely paid for by the US taxpayer, and no copyright is claimed. I recommend contacting the authors for a copy.

The second was why the VA hasn’t participated in either animal or human follow-on studies to the 2015 Northwestern University GABAergic mechanisms regulated by miR-33 encode state-dependent fear. That study’s relevance to PTSD, this review’s subject, and the VA’s mission is too important to ignore. For example:

“Fear-inducing memories can be state dependent, meaning that they can best be retrieved if the brain states at encoding and retrieval are similar.

“It’s difficult for therapists to help these patients,” Radulovic said, “because the patients themselves can’t remember their traumatic experiences that are the root cause of their symptoms.”

The findings imply that in response to traumatic stress, some individuals, instead of activating the glutamate system to store memories, activate the extra-synaptic GABA system and form inaccessible traumatic memories.”

I curated the research in A study that provided evidence for basic principles of Primal Therapy. These researchers have published several papers since then. Here are the abstracts from three of them:

Experimental Methods for Functional Studies of microRNAs in Animal Models of Psychiatric Disorders

“Pharmacological treatments for psychiatric illnesses are often unsuccessful. This is largely due to the poor understanding of the molecular mechanisms underlying these disorders. We are particularly interested in elucidating the mechanism of affective disorders rooted in traumatic experiences.

To date, the research of mental disorders in general has focused on the causal role of individual genes and proteins, an approach that is inconsistent with the proposed polygenetic nature of these disorders. We recently took an alternative direction, by establishing the role of miRNAs in the coding of stress-related, fear-provoking memories.

Here we describe in detail our work on the role of miR-33 in state-dependent learning, a process implicated in dissociative amnesia, wherein memories formed in a certain brain state can best be retrieved if the brain is in the same state. We present the specific experimental approaches we apply to study the role of miRNAs in this model and demonstrate that miR-33 regulates the susceptibility to state-dependent learning induced by inhibitory neurotransmission.”

Neurobiological mechanisms of state-dependent learning

“State-dependent learning (SDL) is a phenomenon relating to information storage and retrieval restricted to discrete states. While extensively studied using psychopharmacological approaches, SDL has not been subjected to rigorous neuroscientific study.

Here we present an overview of approaches historically used to induce SDL, and highlight some of the known neurobiological mechanisms, in particular those related to inhibitory neurotransmission and its regulation by microRNAs (miR).

We also propose novel cellular and circuit mechanisms as contributing factors. Lastly, we discuss the implications of advancing our knowledge on SDL, both for most fundamental processes of learning and memory as well as for development and maintenance of psychopathology.”

Neurobiological correlates of state-dependent context fear

“Retrieval of fear memories can be state-dependent, meaning that they are best retrieved if the brain states at encoding and retrieval are similar. Such states can be induced by activating extrasynaptic γ-aminobutyric acid type A receptors (GABAAR) with the broad α-subunit activator gaboxadol. However, the circuit mechanisms and specific subunits underlying gaboxadol’s effects are not well understood.

Here we show that gaboxadol induces profound changes of local and network oscillatory activity, indicative of discoordinated hippocampal-cortical activity, that were accompanied by robust and long-lasting state-dependent conditioned fear. Episodic memories typically are hippocampus-dependent for a limited period after learning, but become cortex-dependent with the passage of time.

In contrast, state-dependent memories continued to rely on hippocampal GABAergic mechanisms for memory retrieval. Pharmacological approaches with α- subunit-specific agonists targeting the hippocampus implicated the prototypic extrasynaptic subunits (α4) as the mediator of state-dependent conditioned fear.

Together, our findings suggest that continued dependence on hippocampal rather than cortical mechanisms could be an important feature of state-dependent memories that contributes to their conditional retrieval.”

Here’s an independent 2017 Netherlands/UC San Diego review that should bring these researchers’ efforts to the VA’s attention:

MicroRNAs in Post-traumatic Stress Disorder

“Post-traumatic stress disorder (PTSD) is a psychiatric disorder that can develop following exposure to or witnessing of a (potentially) threatening event. A critical issue is to pinpoint the (neuro)biological mechanisms underlying the susceptibility to stress-related disorder such as PTSD, which develops in the minority of ~15% of individuals exposed to trauma.

Over the last few years, a first wave of epigenetic studies has been performed in an attempt to identify the molecular underpinnings of the long-lasting behavioral and mental effects of trauma exposure. The potential roles of non-coding RNAs (ncRNAs) such as microRNAs (miRNAs) in moderating or mediating the impact of severe stress and trauma are increasingly gaining attention. To date, most studies focusing on the roles of miRNAs in PTSD have, however, been completed in animals, using cross-sectional study designs and focusing almost exclusively on subjects with susceptible phenotypes.

Therefore, there is a strong need for new research comprising translational and cross-species approaches that use longitudinal designs for studying trajectories of change contrasting susceptible and resilient subjects. The present review offers a comprehensive overview of available studies of miRNAs in PTSD and discusses the current challenges, pitfalls, and future perspectives of this field.”

Here’s a 2017 Netherlands human study that similarly merits the US Veterans Administration’s attention:

Circulating miRNA associated with posttraumatic stress disorder in a cohort of military combat veterans

“Posttraumatic stress disorder (PTSD) affects many returning combat veterans, but underlying biological mechanisms remain unclear. In order to compare circulating micro RNA (miRNA) of combat veterans with and without PTSD, peripheral blood from 24 subjects was collected following deployment, and isolated miRNA was sequenced.

PTSD was associated with 8 differentially expressed miRNA. Pathway analysis shows that PTSD is related to the axon guidance and Wnt signaling pathways, which work together to support neuronal development through regulation of growth cones. PTSD is associated with miRNAs that regulate biological functions including neuronal activities, suggesting that they play a role in PTSD symptomatology.”

See the below comments for reasons why I downgraded this review’s rating.

https://link.springer.com/article/10.1007/s11920-018-0887-x “Stress Response Modulation Underlying the Psychobiology of Resilience” (not freely available)

The lifelong impact of maternal postpartum behavior

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Brain development, Cerebrum, Cortisol, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Limbic system, Neurochemicals, Oxytocin, Stress, Vasopressin , , , , , ,

This 2018 French/Italian/Swiss rodent study was an extension of the work done by the group of researchers who performed Prenatal stress produces offspring who as adults have cognitive, emotional, and memory deficiencies and Treating prenatal stress-related disorders with an oxytocin receptor agonist:

“Reduction of maternal behavior [nursing behavior, grooming, licking, carrying pups] was predictive of behavioral disturbances in PRS [prenatally restraint stressed] rats as well as of the impairment of the oxytocin and its receptor gene expression.

Postpartum carbetocin [an oxytocin receptor agonist unavailable in the US] corrected the reduction of maternal behavior induced by gestational stress as well as the impaired oxytocinergic system in the PRS progeny, which was associated with reduced risk-taking behavior.

Moreover, postpartum carbetocin had an anti-stress effect on HPA [hypothalamic-pituitary-adrenal] axis activity in the adult PRS progeny and increased hippocampal mGlu5 [type 5 metabotropic glutamate] receptor expression in aging.

Early postpartum carbetocin administration to the dam enhances maternal behavior and prevents all the pathological outcomes of PRS throughout the entire lifespan of the progeny..proves that the defect in maternal care induced by gestational stress programs the development of the offspring.“


This chart from Figure 4 summarized the behavioral performance of aged adult male progeny in relation to the experimental variables of:

  1. Stress administered to the mothers three times daily every day during the second half of pregnancy up until delivery; and
  2. The effects on the mothers’ behavior of daily carbetocin administration during postpartum days 1 through 7.

The symbols denote which of these relationships had statistically significant effects:

  • “* p [Pearson’s correlation coefficient] < 0.05 PRS-Saline vs. CONT-Saline;
  • # p < 0.05 PRS-Carbetocin vs. the PRS-Saline group.”

There are many interesting aspects to this study. Ask the corresponding coauthor Dr. Sara Morley-Fletcher at sara.morley-fletcher@univ-lille1.fr for a copy.

One place the paper referenced the researchers’ previous studies was in this context:

“Postpartum carbetocin administration reversed the same molecular and behavioral parameters in the hippocampus, as does adult chronic carbetocin treatment, i.e. it led to a correction of the HPA axis negative feedback mechanisms, stress and anti-stress gene expression, and synaptic glutamate release. The fact that postpartum carbetocin administration [to the stressed mothers in this study] had the same effect [on the PRS infants in this study] as adult carbetocin treatment [to the PRS offspring in the previous study] indicates a short-term effect of carbetocin when administered in adulthood and a reprogramming (long-term) effect lasting until an advanced age when administered in early development.”

This group’s research seems to be constrained to treatments of F0 and F1 generations. What intergenerational and transgenerational effects would they possibly find by extending research efforts to F2 and F3 generations?

As the study may apply to humans:

The study demonstrated that stresses during the second half of pregnancy had lifelong impacts on both the mothers’ and offsprings’ biology and behavior. Studies and reviews that attribute similar human biological and behavioral conditions to unknown causes, or shuffle them into the black box of individual differences, should be recognized as either disingenuous or insufficient etiological investigations.

The study showed that prevention of gestational stress was a viable strategy. The control group progeny’s biology and behavior wasn’t affected by carbetocin administration to their mothers because neither they nor their mothers had experience-dependent epigenetic deficiencies.

The study demonstrated a biological and behavioral cure for the PRS offspring by changing their stressed mothers’ behaviors during a critical period of their development. The above excerpt characterized improving the mothers’ behaviors as a long-term cure for the PRS descendants, as opposed to the short-term cure of administering carbetocin to the PRS children when they were adults.

What long-term therapies may be effective for humans who had their developmental trajectories altered by their mothers’ stresses during their gestation, or who didn’t get the parental care they needed when they needed it?

https://www.sciencedirect.com/science/article/pii/S0161813X18301062 “Reduced maternal behavior caused by gestational stress is predictive of life span changes in risk-taking behavior and gene expression due to altering of the stress/anti-stress balance” (not freely available)

Prenatal stress produces offspring who as adults have cognitive, emotional, and memory deficiencies

gettingwell4 4-5 stars Advanced knowledge, Brain development, Cerebrum, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Limbic system, Memory, Neurochemicals, Oxytocin, Stress , , , , ,

This 2018 French/Italian/Swiss rodent study used a prenatally restraint stressed (PRS) model to create problems that could be resolved by various chemicals:

“S 47445 is a positive modulator of glutamate AMPA-type receptors, possessing neurotrophic and enhancing synaptic plasticity effects as well as pro-cognitive and anti-stress properties.

Most of studies examining the antidepressant effects of new molecules are carried out using behavioral tests performed in unstressed animals.

Corticosterone-treated mice and rats exposed to chronic stress are models that do not recapitulate the early programming of stress-related disorders, which likely originates in the perinatal period. The PRS rat model is characterized by a prolonged corticosterone response to stress and by abnormal behavior.

All the behavioral alterations induced by PRS were corrected by chronic S 47445 administration at both doses.”

The paper included a section comparing S 47445 to ketamine:

“Ketamine, however, causes severe cognitive impairment and psychotomimetic [mimics the symptoms of psychosis, reference not freely available] effects that are direct consequences of the prolonged inhibition of NMDA receptors in cortical and hippocampal interneurons, and seriously limit the chronic administration of the drug in the clinical setting. [reference not freely available]

S 47445 by inducing a direct activation of AMPARs displayed an antidepressant activity without the adverse effect of ketamine. Indeed, contrary to ketamine, S 47445 presented no psychotomimetic effects and induced no occurrence of spontaneous epileptic seizures. [reference freely available] Moreover, S 47445 also presented pro-cognitive properties.”

Compare the above with this April 2018 Chicago Tribune story that had opinions with no linked references:

“ketamine, an anesthetic used to sedate both people and animals before surgery. It’s also a notorious street drug, abused by clubgoers seeking a trancelike, hallucinatory high. But in recent years, numerous studies have found that ketamine can be an effective and speedy treatment for people with depression.”

Which coverage better informed us?

Treating prenatal stress-related disorders with an oxytocin receptor agonist was performed by several of this paper’s coauthors. One references to it was:

“We have already reported that depolarization-evoked glutamate release in the ventral hippocampus is negatively correlated with risk-taking behavior of PRS rats, and that such correlation can be corrected by chronic treatment with monoaminergic/ melatoninergic antidepressants or oxytocin receptor agonist. Thus, an impairment of glutamatergic transmission in the ventral hippocampus lies at the core of the pathological phenotype of PRS rats.”

Looking at the above graphic of the experimental design, I’m not sure why the term perinatal (occurring during or pertaining to the phase surrounding the time of birth) was used in the paper’s title and content to describe the stress period. The pregnant females were stressed three times every day during the second half of pregnancy up until delivery, so the prenatal (previous to birth) term was more applicable.

So, how does this study help humans?

One takeaway is to avoid stressing pregnant mothers-to-be if her children will be expected to become adults without cognitive, emotional, and behavioral problems.

The study demonstrated one way prenatal events cause lifelong effects. The PRS model provides another example of why it’s useless to ask adult humans to self-report causes of epigenetic problems in their lives when these originated before birth, during infancy, or in early childhood, well before humans develop sufficient cognitive capability to recognize such situations. It’s incomprehensible that this unreliable paradigm is still given significant weight in stress studies, especially when experimental designs:

“Do not recapitulate the early programming of stress-related disorders, which likely originates in the perinatal period.”

Also, a relevant difference between humans and PRS rats is that we can ourselves individually change our responses to experiential causes of ongoing adverse effects. Standard methodologies can only apply external treatments such as those mentioned above.

https://www.sciencedirect.com/science/article/pii/S0028390818301291 “The reduction in glutamate release is predictive of cognitive and emotional alterations that are corrected by the positive modulator of AMPA receptors S 47445 in perinatal stressed rats” (not freely available) Thanks to coauthors Stefania Maccari and Dr. Jerome Mairesse for providing a copy.