Stress

Epigenetics research and evolution

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

This 2017 UK essay was a longish review of how epigenetics and other research has informed evolutionary theory:

“There are several processes by which directed evolutionary change occurs – targeted mutation, gene transposition, epigenetics, cultural change, niche construction and adaptation.

Evolution is an ongoing set of iterative interactions between organisms and the environment. Directionality is introduced by the agency of organisms themselves.”

A few takeaway items concerned:

“It is of course the functional phenotype that is ‘seen’ by natural selection. DNA sequences are not directly available for selection other than through their functional consequences.

The comparative failure of genome-wide association studies to reveal very much about the genetic origins of health and disease is one of the most important empirical findings arising from genome sequencing.

Environmental epigenetic impacts on biology and disease include:

  • Worldwide differences in regional disease frequencies
  • Low frequency of genetic component of disease as determined with genome wide association studies (GWAS)
  • Dramatic increases in disease frequencies over past decades
  • Identical twins with variable and discordant disease frequency
  • Environmental exposures associated with disease
  • Regional differences and rapid induction events in evolution“

The above list was from the cited 2016 review “Developmental origins of epigenetic transgenerational inheritance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4933018

Further points about behavior’s role in evolution:

“Differential mutation rates are not essential to enable organisms to guide their own evolution.

If organisms have agency and, within obvious limits, can choose their lifestyles, and if these lifestyles result in inheritable epigenetic changes, then it follows that organisms can at least partially make choices that can have long-term evolutionary impact.”

These discussions provided support for the central question of The PRice “equation” for individually evolving: Which equation describes your life?:

“Applying the “How does a phenotype influence its own change?” question to a person:

How can a person remedy their undesirable traits – many of which are from their ancestral phenotype – and acquire desirable traits?”

http://www.mdpi.com/2079-7737/6/4/47/htm “Was the Watchmaker Blind? Or Was She One-Eyed?”

The pain societies instill into children

gettingwell4 2-3 stars Required further work, Beliefs, Cerebrum, Epigenetics, Memory, Primal Therapy, Stress , , , , ,

The human subjects of this 2017 Swiss study had previously been intentionally traumatized by Swiss society:

“Swiss former indentured child laborers (Verdingkinder) were removed as children from their families by the authorities due to different reasons (poverty, being born out of wedlock) and were placed to live and work on farms. This was a practice applied until the 1950s and many of the Verdingkinder were subjected to childhood trauma and neglect during the indentured labor.

DNA methylation modifications indicated experiment-wide significant associations with the following complex posttraumatic symptom domains: dissociation, tension reduction behavior and dysfunctional sexual behavior.”


https://bmcresnotes.biomedcentral.com/articles/10.1186/s13104-017-3082-y “A pilot investigation on DNA methylation modifications associated with complex posttraumatic symptoms in elderly traumatized in childhood”

Imagine being taken away from your family during early childhood for no other reason than your parents weren’t married.

Consider just a few of the painful feelings such a child had to deal with then and ever since:

  • I’m unloved.
  • Alone.
  • No one can help me.

Imagine some of the ways a child had to adapt during their formative years because of this undeserved punishment:

  • How fulfilling it would be to believe that they were loved, even by someone they couldn’t see, touch, or hear.
  • How fulfilling it would be to get attention from someone, anyone.
  • How a child became conditioned to do things by themself without asking for help.

The study described a minute set of measurements of the subjects’ traumatic experiences and their consequential symptoms. The researchers tried to group this tiny sample of the subjects’ symptoms into a new invented category.

Another example was provided in Is IQ an adequate measure of the quality of a young man’s life?:

“During this time period [between 1955 and 1990], because private adoptions were prohibited by Swedish law, children were taken into institutional care by the municipalities shortly after birth and adopted at a median age of 6 mo, with very few children adopted after 12 mo of age.”

Swedish society deemed local institutional care the initial destination for disenfranchised infants, regardless of whether suitable families were willing and able to adopt the infants. What happened to infants who weren’t adopted by age 1?

Did Swedish society really need any further research to know that an adoptive family’s care would be better for a child than living in an institution?

It’s hard to recognize when our own thoughts, feelings, and behavior provide evidence of childhood pain that’s still with us.

Let’s not hope and believe that the societies we live in will resolve adverse effects of childhood trauma its members caused. Other people may guide us, but each of us has to individually get our life back:

“What is the point of life if we cannot feel and love others? Without feeling, life becomes empty and sterile.

It, above all, loses its meaning.“

Every society has its horror stories. People who have reached some degree of honesty about their early lives and concomitant empathy for others can document these terrible circumstances and events.

Have traumatic effects on children from societal policies ceased?

Epigenetic study methodologies improved in 2017

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Let’s start out 2018 paying more attention to advancements in science that provide sound empirical data and methodology. Let’s ignore and de-emphasize studies and reviews that aren’t much more than beliefs couched in models and memes, whatever their presumed authority.

Let sponsors direct researchers to focus on ultimate causes of diseases. Let’s put research of treatments affecting causes ahead of those that only address symptoms.

Here are two areas of epigenetic research that improved in 2017.

Improved methodologies enabled DNA methylation studies of adenine, one of the four bases of DNA, to advance, such as this 2017 Wisconsin/Minnesota study N6-methyladenine is an epigenetic marker of mammalian early life stress:

“6 mA is present in the mammalian brain, is altered within the Htr2a gene promoter by early life stress and biological sex, and increased 6 mA is associated with gene repression. These data suggest that methylation of adenosine within mammalian DNA may be used as an additional epigenetic biomarker for investigating the development of stress-induced neuropathology.”

Most DNA methylation research is performed on the cytosine and guanine bases.

Other examples of improved methodologies were discussed in this 2017 Japanese study Genome-wide identification of inter-individually variable DNA methylation sites improves the efficacy of epigenetic association studies:

“A strategy focusing on CpG sites with high DNA methylation level variability may attain an improved efficacy..estimated to be 3.7-fold higher than that of the most frequently used strategy.

With ~90% coverage of human CpGs, whole-genome bisulfite sequencing (WGBS) provides the highest coverage among the currently available DNAm [DNA methylation] profiling technologies. However, because of its high cost, it is presently infeasible to apply WGBS to large-scale EWASs [epigenome-wide association studies], which require DNAm profiling of hundreds or thousands of subjects. Therefore, microarrays and targeted bisulfite sequencing are currently practicable for large-scale EWASs and thus, effective strategies to select target regions are essentially needed to improve the efficacy of epigenetic association studies.

DNAm levels measured with microarrays are invariable for most CpG sites in the study populations. As invariable DNAm signatures cannot be associated with exposures, intermediate phenotypes, or diseases, current designs of probe sets are inefficient for blood-based EWASs.”

A review of biological variability

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This 2017 UK/Spanish review subject was biological variability:

“No two cells in a cellular population are the same, and no two individuals of a multi-cellular species are identical-not even if they share the same genetic makeup like monozygotic twins or cloned animals.

Epigenetic and gene expression variability are key contributors to phenotypic differences. There are many possible sources of epigenetic and transcriptional variability, which can be divided into three main categories:

  1. individual-intrinsic factors;
  2. environmental factors; and
  3. random fluctuations, also referred to as stochasticity.”

Most of the review cited cell studies. The reviewers cited their own studies in the Introduction section, for example:

“These studies were among the first to classify disease status or aggressiveness based on variability, where the classical comparison of mean DNA methylation or gene expression levels was not informative.”

to help support a later observation:

“It is critical to obtain a measurement of variability that is independent of the mean to ensure to not confound changes in variability with shifts in mean.”

The review didn’t cover a pertinent aspect of the subject: how standard research approaches miss detecting biological variability.

For example, from Changing an individual’s future behavior even before they’re born that referred to the methodology of genome-wide association studies (GWAS):

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

Another omission was the point made in A study of DNA methylation and age:

“Due to the methods applied in the present study, not all the effects of DNA methylation on gene expression could be detected; this limitation is also true for previously reported results.

The textbook case of DNA methylation regulating gene expression (the methylation of a promoter and silencing of a gene) remains undetected in many cases because in an array analysis, an unexpressed gene shows no signal that can be distinguished from background and is therefore typically omitted from the analysis.”

The reviewers also didn’t cover variability in phenotypic behaviors. I’ll repeat my thoughts from A limited study of parental transmission of anxiety/stress-reactive traits:

“How did parental behavioral transmission of behavioral traits and epigenetic changes become a subject not worth investigating? These traits and effects can be seen everyday in real-life human interactions, and in every human’s physiology.”

Perhaps these omissions reflected the reviewers’ focus on their specialties?

Perhaps it isn’t politically correct to discuss or fund research on aspects of biological variability that would advance science by falsifying preferred previous findings? Or advance science by measuring the extent of parental involvement in shaping their offspring’s behavioral and biological variability?

What do you think?

http://onlinelibrary.wiley.com/doi/10.1002/bies.201700148/full “Epigenetic and Transcriptional Variability Shape Phenotypic Plasticity”

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.

What’s an appropriate exercise recovery time?

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This 2017 New Zealand human research studied the effect of one supplement on recovery from exercise-induced muscle damage:

“Eccentric exercise is known to bring about microstructural damage to muscle, initiating an inflammatory cascade involving various reactive oxygen species. This, in turn, can significantly impair physical performance over subsequent days. Taurine, a powerful endogenous antioxidant, has previously been shown to have a beneficial effect on muscle damage markers and recovery when taken for a few days to several weeks prior to eccentric exercise.

The amount of powder was set at 0.1 g∙kg−1 body weight∙day−1, based on several studies that found no adverse effects at levels of up to 10 g∙day. No participant was at a body weight that resulted in consuming more than 10 g∙day.

Supplementation with taurine twice daily for 72 h following eccentric exercise-induced muscle damage may improve eccentric performance recovery of the biceps brachii in healthy males.”

My main takeaway from the study came from this finding:

“Our results show that neither treatment group fully recovered force output by 72 h.”

I was surprised to see that even three days wasn’t enough time for a muscle to fully recover. And the study’s subjects were young males:

“Age = 26.5 ± 6.5 years, height = 180 ± 9.2 cm, mass = 80 ± 11.5 kg. All participants were recreationally fit, engaging in exercise 2–3 times per week.”

This gave me pause to reflect on how inattention to cumulative strain may have produced repetitive stress injuries. I’ve adjusted my workout routines accordingly.

The study listed a number of limitations. An unstated one was that nobody should take supplements in quantities that are many times greater than normal dosages without being informed by quality human experimental evidence.

http://www.mdpi.com/2076-3921/6/4/79/htm “The Effect of Taurine on the Recovery from Eccentric Exercise-Induced Muscle Damage in Males”

How to cure the ultimate causes of migraines?

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Most of the spam I get on this blog comes in as ersatz comments on The hypothalamus couples with the brainstem to cause migraines. I don’t know what it is about the post that attracts internet bots.

The unwanted attention is too bad because the post represents a good personal illustration of “changes in the neural response to painful stimuli.” Last year I experienced three three-day migraines in one month as did the study’s subject. This led to me cycling through a half-dozen medications in an effort to address the migraine causes.

None of the medications proved to be effective at treating the causes. I found one that interrupted the progress of migraines – sumatriptan, a serotonin receptor agonist. I’ve used it when symptoms start, and the medication has kept me from having a full-blown migraine episode in the past year.

1. It may be argued that migraine headache tendencies are genetically inherited. Supporting personal evidence is that both my mother and younger sister have migraine problems. My father, older sister, and younger brother didn’t have migraine problems. Familial genetic inheritance usually isn’t the whole story of diseases, though.

2. Migraine headaches may be an example of diseases that are results of how humans have evolved. From Genetic imprinting, sleep, and parent-offspring conflict:

“Evolutionary theory predicts: that which evolves is not necessarily that which is healthy.

Why should pregnancy not be more efficient and more robust than other physiological systems, rather than less? Crucial checks, balances and feedback controls are lacking in the shared physiology of the maternal–fetal unit.“

Both migraine causes and effects may be traced back to natural lacks of feedback loops. These lacks demonstrate that such physiological feedback wasn’t evolutionarily necessary in order for humans to survive and reproduce.

3. Examples of other processes occurring during prenatal development that also lack feedback loops, and their subsequent diseases, are:

A. Hypoxic conditions per Lack of oxygen’s epigenetic effects are causes of the fetus later developing:

  • “age-related macular degeneration
  • cancer progression
  • chronic kidney disease
  • cardiomyopathies
  • adipose tissue fibrosis
  • inflammation
  • detrimental effects which are linked to epigenetic changes.”

B. Stressing pregnant dams per Treating prenatal stress-related disorders with an oxytocin receptor agonist caused fetuses to develop a:

and abnormalities:

  • in social behavior,
  • in the HPA response to stress, and
  • in the expression of stress-related genes in the hippocampus and amygdala.”

1. What would be a treatment that could cure genetic causes for migraines?

I don’t know of any gene therapies.

2. What treatments could cure migraines caused by an evolved lack of feedback mechanisms?

We humans are who we have become, unless and until we can change original causes. Can we deal with “changes in the neural response to painful stimuli” without developing hopes for therapies or technologies per Differing approaches to a life wasted on beliefs?

3. What treatments could cure prenatal epigenetic causes for migraines?

The only effective solution I know of that’s been studied in humans is to prevent adverse conditions like hypoxia from taking place during pregnancy. The critical periods of our physical development are over once we’re adults, and we can’t unbake a cake.

Maybe science will offer other possibilities. Maybe researchers could do more than their funding sponsors expect?

Differing approaches to a life wasted on beliefs

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Let’s start by observing that people structure their lives around beliefs. As time goes on, what actions would a person have taken to ward off non-confirming evidence?

One response may be that they would engage in ever-increasing efforts to develop new beliefs that justified how they spent their one precious life’s time so far.

Such was my take on beliefs embedded in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684598/pdf/PSYCHIATRY2017-5491812.pdf “Epigenetic and Neural Circuitry Landscape of Psychotherapeutic Interventions”:

“Animal models have shown the benefits of continued environmental enrichment (EE) on psychopathological phenotypes, which carries exciting translational value.

This paper posits that psychotherapy serves as a positive environmental input (something akin to EE).”

The author conveyed his belief that wonderful interventions were going to happen in the future. However, when scrutinized, most human studies have demonstrated NULL effects of psychotherapeutic interventions on causes. Without sound evidence that treatments affect causes, his belief seemed driven by something else.

The author cited findings of research like A problematic study of oxytocin receptor gene methylation, childhood abuse, and psychiatric symptoms as supporting external interventions to tamp down symptoms of patients’ presenting problems. Did any of the 300+ cited references concern treatments where patients instead therapeutically addressed their problems’ root causes?

For an analogous religious example, a person’s belief caused him to spend years of his life trying to convince men to act so that they could get their own planet after death, and trying to convince women to latch onto men who had this belief. A new and apparently newsworthy belief developed from his underlying causes:

“The founder and CEO of neuroscience company Kernel wants “to expand the bounds of human intelligence.” He is planning to do this with neuroprosthetics; brain augmentations that can improve mental function and treat disorders. Put simply, Kernel hopes to place a chip in your brain.

He was raised as a Mormon in Utah and it was while carrying out two years of missionary work in Ecuador that he was struck by what he describes as an “overwhelming desire to improve the lives of others.”

He suffered from chronic depression from the ages of 24 to 34, and has seen his father and stepfather face huge mental health struggles.”

https://www.theguardian.com/small-business-network/2017/dec/14/humans-20-meet-the-entrepreneur-who-wants-to-put-a-chip-in-your-brain “Humans 2.0: meet the entrepreneur who wants to put a chip in your brain”

The article stated that he had given up Mormonism. There was nothing to suggest, though, that he had therapeutically addressed any underlying causes for his misdirected thoughts, feelings, and behavior.

So he developed other beliefs instead.

What can people do to keep their lives from being wasted on beliefs? As mentioned in What was not, is not, and will never be:

“The problem is that spending our time and efforts on these ideas, beliefs, and behaviors won’t ameliorate their motivating causes. Our efforts only push us further away from our truths, with real consequences: a wasted life.”

The goal of the therapeutic approach advocated by Dr. Arthur Janov’s Primal Therapy is to remove the force of presenting problems’ motivating causes. Success in reaching this goal is realized when patients become better able to live their own lives.

Epigenetic effects of microRNA on fetal heart development

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This 2017 Australian review’s subject was epigenetic impacts involving microRNA in adverse intrauterine environments, and how these affected fetal heart tissue development:

“We describe how an adverse intrauterine environment can influence the expression of miRNAs (a sub-set of non-coding RNAs) and how these changes may impact heart development. Potential consequences of altered miRNA expression in the fetal heart include; Hypoxia inducible factor (HIF) activation, dysregulation of angiogenesis, mitochondrial abnormalities and altered glucose and fatty acid transport/metabolism.

This feedback network between miRNAs and other epigenetic pathways forms an epigenetics–miRNA regulatory circuit that organizes the whole gene expression profile. The human heart encodes over 700 miRNAs.”

A 2016 review Lack of oxygen’s epigenetic effects also provided a details about hypoxia. Those reviewers importantly pointed out the natural lack of a feedback mechanism to the HIF-1α signaling source, and how this evolutionary lack contributed to diseases.

http://www.mdpi.com/1422-0067/18/12/2628/htm “Adverse Intrauterine Environment and Cardiac miRNA Expression”

Do you have your family’s detailed medical histories?

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Imagine that you were a parent who puzzled over the mystery of your pre-teen daughter’s hyperactive behavior. Without detailed family medical histories, would anyone recognize this as a preprogammed phenotype?

Could anyone trace the daughter’s behavior back to her maternal great-grandmother being treated with glucocorticoids near the end of the second trimester of carrying her grandfather?

Such was a finding of a 2017 Canadian guinea pig study that was undertaken to better inform physicians of the transgenerationally inherited epigenetic effects of glucocorticoid treatments commonly prescribed during human pregnancies:

“This study presents the first evidence that prenatal treatment with sGC [synthetic glucocorticoid] results in transgenerational paternal transmission of hyperactivity and altered hypothalamic gene expression through three generations of young offspring. Female offspring appear to be more sensitive than male offspring to the programming effects of sGC, which suggests an interaction between sGC and sex hormones or sex-linked genes. Paternal transmission to F3 strongly implicates epigenetic mechanisms in the process of transmission, and small noncoding RNAs likely play a major role.”

Some details of the study included:

Veh[icle] was the control group initially treated with saline.

The study was informative and conclusive for the aspects studied. From the Methods section:

“Data from same-sex littermates were meaned to prevent litter bias. Sample sizes (N) correspond to independent litters, and not to the total number of offspring across all litters.

Power analyses based on previous studies determined N ≥ 8 sufficient to account for inter-litter variability and detect effects in the tests performed.”

https://www.nature.com/articles/s41598-017-11635-w “Prenatal Glucocorticoid Exposure Modifies Endocrine Function and Behaviour for 3 Generations Following Maternal and Paternal Transmission”

What is a father’s role in epigenetic inheritance?

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The agenda of this 2017 Danish review was to establish a paternal role in intergenerational and transgenerational epigenetic inheritance of metabolic diseases:

“There are four windows of susceptibility which have major importance for epigenetic inheritance of acquired paternal epigenetic changes:

  1. paternal primordial germ cell (PGC) development,
  2. prospermatogonia stages,
  3. spermatogenesis, and
  4. during preimplantation.”

The review was a long read as the authors discussed animal studies. When it came to human studies near the paper’s end, though, the tone was of a “we know this is real, we just have to find it” variety. The authors acknowledged:

“To what extent the described DNA methylation changes influence the future health status of offspring by escaping remodeling in the preimplantation period as well as in future generations by escaping remodeling in PGC remodeling has yet to be determined.

These studies have not yet provided an in-depth understanding of the specific mechanisms behind epigenetic inheritance or exact effect size for the disease risk in offspring.

Pharmacological approaches have reached their limits..”

before presenting their belief that a hypothetical series of future CRISPR-Cas9 experiments will demonstrate the truth of their agenda.

The review focused on 0.0001% of the prenatal period for what matters with the human male – who he was at the time of a Saturday night drunken copulation – regarding intergenerational and transgenerational epigenetic inheritance of metabolic diseases.

The human female’s role – who she was at conception AND THEN what she does or doesn’t do during the remaining 99.9999% of the prenatal period to accommodate the fetus and prevent further adverse epigenetic effects from being intergenerationally and transgenerationally transmitted  – wasn’t discussed.

Who benefits from this agenda’s narrow focus?

If the review authors sincerely want to:

“Raise societal awareness of behavior to prevent a further rise in the prevalence of metabolic diseases in future generations..”

then EARN IT! Design and implement HUMAN studies to test what’s already known from epigenetic inheritance animal studies per Experience-induced transgenerational programming of neuronal structure and functions. Don’t disguise beliefs with the label of science.

http://jme.endocrinology-journals.org/content/early/2017/12/04/JME-17-0189.full.pdf “DNA methylation in epigenetic inheritance of metabolic diseases through the male germ line”

Transgenerational pathological traits induced by prenatal immune activation

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The third paper of Transgenerational epigenetic inheritance week was a 2016 Swiss rodent study of immune system epigenetic effects:

“Our study demonstrates for, we believe, the first time that prenatal immune activation can negatively affect brain and behavioral functions in multiple generations. These findings thus highlight a novel pathological aspect of this early-life adversity in shaping disease risk across generations.”

The epigenetic effects noted in the initial round of experiments included:

  • F1 child and F2 grandchild impaired sociability;
  • F1 and F2 abnormal fear expression;
  • F1 but not F2 sensorimotor gating deficiencies; and
  • F2 but not F1 behavioral despair associated with depressive-like behavior.

These transgenerational effects emerged in both male and female offspring. The prenatal immune activation timing corresponded to the middle of the first trimester of human pregnancy.

The effects were found to be mediated by the paternal but not maternal lineage. The researchers didn’t develop a maternal lineage F3 great-grandchild generation.

The next round of experiments done with the paternal lineage F3 great-grandchildren noted these epigenetic effects:

  • The F3 great-grandchildren had impaired sociability, abnormal fear expression and behavioral despair; and
  • The F3 great-grandchildren had normal sensorimotor gating.

Since the first round of tests didn’t show sex-dependent effects, the F3 great-grandchildren were male-only to minimize the number of animals.

Samples of only the amygdalar complex were taken to develop findings of transcriptomic effects of prenatal immune activation.

Items in the Discussion section included:

  1. The F2 grandchild and F3 great-grandchild generations’ phenotype of impaired sociability, abnormal fear expression and behavioral despair demonstrated that prenatal immune activation likely altered epigenetic marks in the germ line of the F1 children which resisted erasure and epigenetic reestablishment during germ cell development.
  2. Abnormal F1 child sensorimotor gating followed by normal F2 grandchild and F3 great-grandchild sensorimotor gating demonstrated that prenatal immune activation may also modify somatic but not germ cells.
  3. Non-significant F1 child behavioral despair followed by F2 grandchild and F3 great-grandchild behavioral despair demonstrated that prenatal immune activation may modify F1 germ cells sufficiently to develop a transgenerational phenotype, but unlike item 1 above, somatic cells were insufficiently modified, and the phenotype skipped the F1 children.
  4. Studies were cited that prenatal immune activation later in the gestational process may produce different effects.

The initial round of experiments wasn’t definitive for the maternal lineage. As argued in Transgenerational effects of early environmental insults on aging and disease and A review of epigenetic transgenerational inheritance of reproductive disease, testing of maternal lineage F3 great-grandchildren was needed to control for the variable of direct F2 grandchild germ-line exposure.

Also, effects that didn’t reach statistical significance in the maternal lineage F1 children and F2 grandchildren may have been different in the F3 great-grandchildren. The researchers indirectly acknowledged this lack by noting that these and other effects of immune challenges in a maternal lineage weren’t excluded by the study.

https://www.nature.com/mp/journal/v22/n1/pdf/mp201641a.pdf “Transgenerational transmission and modification of pathological traits induced by prenatal immune activation” (not freely available)

The study’s lead researcher authored a freely-available 2017 review that placed this study in context and provided further details from other studies:

http://www.nature.com/tp/journal/v7/n5/full/tp201778a.html “Epigenetic and transgenerational mechanisms in infection-mediated neurodevelopmental disorders”

Experience-induced transgenerational programming of neuronal structure and functions

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The second paper of Transgenerational epigenetic inheritance week was a 2017 German/Israeli review focused on:

“The inter- and transgenerational effects of stress experience prior to and during gestation..the concept of stress-induced (re-)programming in more detail by highlighting epigenetic mechanisms and particularly those affecting the development of monoaminergic transmitter systems, which constitute the brain’s reward system.

We offer some perspectives on the development of protective and therapeutic interventions in cognitive and emotional disturbances resulting from preconception and prenatal stress.”

The reviewers noted that human studies have difficulties predicting adult responses to stress that are based on gene expression and early life experience. Clinical studies that experimentally manipulate the type, level and timing of the stressful exposure aren’t possible. Clinical studies are also predicated on the symptoms being recognized as disorders and/or diseases.

The researchers noted difficulties in human interventions and treatments. Before and during pregnancy, and perinatal periods are where stress effects are largest. But current human research hasn’t gathered sufficient findings to develop practical guidelines for early intervention programs.

I’m not persuaded by arguments that cite the difficulties of performing human research on transgenerational epigenetic inheritance. There are overwhelming numbers of people who have obvious stress symptoms: these didn’t develop in a vacuum.

Researchers:

  • Design human studies to test what’s known from transgenerational epigenetic inheritance animal studies that will include documenting the subjects’ detailed histories with sufficient biometric samples and data obtained from their lineage.
  • Induce pregnant subjects to at least temporarily avoid what’s harmful for them and/or the offspring, in favor of what’s beneficial.
  • Document the subjects’ actions with history and samples.

I acknowledge that economic incentives may not be enough to get people to participate. I’m familiar with a juvenile sickle-cell study that didn’t get enough subjects despite offering free transportation and hundreds of dollars to the caregivers per visit. The main problem seemed to be that the additional income would be reported and threaten the caregivers’ welfare benefits.

Stop whining that your jobs are difficult, researchers. Society doesn’t owe you a job. EARN IT – get yourself and the people in your organization motivated to advance science!

http://www.sciencedirect.com/science/article/pii/S014976341630731X “Experience-induced transgenerational (re-)programming of neuronal structure and functions: Impact of stress prior and during pregnancy” (not freely available)

Transgenerational effects of early environmental insults on aging and disease

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The first paper of Transgenerational epigenetic inheritance week was a 2017 Canadian/Netherlands review that’s organized as follows:

“First, we address mechanisms of developmental and transgenerational programming of disease and inheritance. Second, we discuss experimental and clinical findings linking early environmental determinants to adverse aging trajectories in association with possible parental contributions and sex-specific effects. Third, we outline the main mechanisms of age-related functional decline and suggest potential interventions to reverse negative effects of transgenerational programming.”

A transgenerational phenotype was defined as an epigenetic modification that was maintained at least either to F2 grandchildren in the paternal lineage, or to F3 great-grandchildren in the maternal lineage.

The reviewers noted that mechanisms of transgenerational programming are complex and multivariate.  Severity, timing, and type of exposure; lineage of transmission; germ cell exposure; and gender of an organism were the main factors that may determine consequences. Mechanisms reviewed were:

  1. Parental exposure to an adverse environment;
  2. Altered maternal behavior and care of offspring; and
  3. Experience-dependent modifications of the epigenome.

There was a long list of diseases and impaired functionalities that were consequences of ancestral experiences and exposures. Most studies were of animals, but a few were human, such as those done on effects of extended power outages during a Quebec ice storm of January 1998.

One intervention that was effective in reversing a transgenerational phenotype induced by deficient rodent maternal care was to place pups with a caring foster female soon after birth. It’s probably unacceptable in human societies to preemptively recognize all poor-care human mothers and remove the infant to caring foster mothers. But researchers could probably find enough instances to develop studies of the effectiveness of such placements in reversing a transgenerational phenotype.

The review didn’t have suggestions for reversing human transgenerational phenotypes, just “potential interventions to reverse negative effects of transgenerational programming.” Interventions suggested for humans – exercise, enriched lifestyle, cognitive training, dietary regimens, and expressive art and writing therapies – only reduced impacts of transgenerational epigenetic effects.

Tricky wording of “reverse negative effects of transgenerational programming” showed that research paradigms weren’t aimed at resolving causes. The review was insufficient for the same reasons mentioned in How one person’s paradigms regarding stress and epigenetics impedes relevant research, prompting my same comment:

Aren’t people interested in human treatments of originating causes so that their various symptoms don’t keep bubbling up? Why wouldn’t research paradigms be aligned accordingly?

When reversals of human phenotypes aren’t researched, problems may compound by being transmitted to the next generations.

http://www.sciencedirect.com/science/article/pii/S014976341630714X “Transgenerational effects of early environmental insults on aging and disease incidence” (not freely available)

It’s transgenerational epigenetic inheritance week!

gettingwell4 4-5 stars Advanced knowledge, Brain development, Cerebrum, Epigenetics, Immune system, Limbic system, Lower brain, Memory, Neurochemicals, Stress , , , ,

Transgenerational epigenetic inheritance is a subject whose time has come. This week I sequentially curated two 2017 reviews and two 2016 studies of the subject, and ended with a meta-analysis of human preventive treatments:

It’s the opposite of advancing science for those in the funding chain to give lip service to the subject, and then create an atmosphere where proposals to extend experiments to subsequent generations to study possible transgenerational epigenetic effects are neither encouraged nor funded.

Does living near a forest keep your amygdala healthier?

gettingwell4 2-3 stars Required further work, Amygdala, Anterior cingulate cortex, Cerebrum, Cortisol, Hippocampus, Limbic system, Neurochemicals, Stress ,

A thought-provoking post from A Paper a Day Keeps the Scientist Okay entitled “Living Near a Forest Keeps Your Amygdala Healthier” referenced a 2017 German human study which found:

“..a relationship between place of residence and brain health: those city dwellers living close to a forest were more likely to show indications of a physiologically healthy amygdala structure and were therefore presumably better able to cope with stress.”

The researchers accomplished the imperative of meeting the study’s stated objective:

“We set out to identify and characterize the geographical elements of a city that are associated with these brain structures following a suggestion by Kennedy and Adolph that studies should begin to derive recommendations for urban planning and architecture.

The results of our study may suggest that forests in and around the cities are a valuable resource that should be promoted. However future longitudinal studies are needed to investigate the causal directionality of the effect in order to disentangle whether more forest in ones habitat facilitates brain structural integrity or potentially those people with better brain structural integrity choose to live closer to forests. Moreover we need to investigate whether living close to the forest is associated with an absence of risk factors such as noise, air pollution or stress and thereby has beneficial effects or whether the forest itself constitutes a salutary factor that promotes well-being.”

https://www.nature.com/articles/s41598-017-12046-7 “In search of features that constitute an “enriched environment” in humans: Associations between geographical properties and brain structure”

A major limitation of this study’s methodology was intentional non-use of an available data source. Referring to Do we need to study the brain to understand the mind? posted earlier this week:

“Self-report is still the gold standard for assessing emotional experience and the contents of thought. Isn’t it easier just to ask?”

These researchers put the forest before the trees, and designed a study that didn’t ask subjects important questions such as why they lived where they lived. The researchers inferred sketchy fMRI-geography associations because they didn’t solicit relevant primary information via individual self-reports.

I don’t live in Berlin, and I’m not part of the selected cohort, but I otherwise generally meet this study’s subject parameters. Something in my past causes me to actively select housing that isn’t in a noisy environment. If I were asked why I lived where I lived, my answer would have included:

  • A deciding factor in why I sold my second house was traffic noise in wintertime;
  • A deciding factor in why I bought my fourth house was its location in the housing development’s center, away from street noise; and
  • A deciding factor in why I live where I now live is the house’s orientation away from both direct and reflective traffic noise sources.

Processing my hypothetical fMRI data with my self-reported historical housing choices may or may not have found:

“Geographical features in the proximal participants’ habitat are associated with brain integrity.”

Using better-quality information of self-reports, though, it’s unlikely that an association this study would have found to be significant – a chance fact that I live within one kilometer of a forest – would have been deemed significant.