Control group

The role of DNMT3a in fear memories

gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Epigenetics, Hippocampus, Limbic system, Memory, Stress , , , , ,

This 2018 Chinese rodent study found:

“Elevated Dnmt3a [a DNA methyltransferase] level in the dorsal dentate gyrus (dDG) of hippocampus was associated with the absence of fear renewal in an altered context after extinction training. Overexpression and knockdown of Dnmt3a in the dDG regulated the occurrence of fear renewal in a bi-directional manner.

We found that renewal of remote fear memory can be prevented, and the absence of renewal was concurrent with an elevated Dnmt3a level.

Our results indicate that Dnmt3a in the dDG is a key regulator of fear renewal after extinction, and Dnmt3a may play a critical role in controlling fear memory return and thus has therapeutic values.”

The study was a collection of five experiments investigating causes and effects of biology and behavior. The researchers used different techniques to achieve their goals. I’ve quoted extensively below to show some background and results.

“Alterations in histone acetylation and DNA methylation are involved in the formation and extinction of long-term memory. DNMTs catalyze the cytosine methylation and are required to establish and maintain genomic methylation.

Dnmt3a and Dnmt3b are de novo DNA methyltransferases. Dnmt1 is the maintenance DNA methyltransferase.

  1. Dnmt3a expression was elevated in the dDG after extinction training followed by a brief memory retrieval (Rec+Ext), which was associated with the absence of fear renewal when tested in an altered context.
  2. Increasing Dnmt3a expression in the dDG using AAV [recombinant adeno-associated virus] expression led to the prevention of fear renewal following a standard extinction training protocol. 
  3. Knockdown of Dnmt3a in the dDG using CRISPR/Cas9 resulted in fear renewal following Rec+Ext protocol.
  4. Renewal of remote fear memory can be prevented using the Rec+Ext protocol.
  5. The absence of renewal was concurrent with an elevated Dnmt3a level.

Current exposure therapy, although effective in many patients, suffers from the inability to generalize its efficacy over time, or is limited by the potential return of adverse memory in the new/novel contexts. These limitations are caused by the context-dependent nature of extinction which is widely viewed as the biological basis of exposure therapy.

Achieving a context-independent extinction may significantly reduce fear renewal to improve the efficacy of exposure therapy. Our current study suggests that the effectiveness of these approaches, and ultimately the occurrence of fear renewal, is determined by the level of Dnmt3a after extinction training, especially in the dDG.

There are two potential mechanisms underlying extinction, one is erasure or updating of the formed memory, and the other is the formation of a new extinction memory which suppresses or competes with the existing memory in a context-dependent manner. While most studies favor the suppression mechanism in the adult, limited studies do suggest that erasure occurs in the immature animals.

We propose that if Dnmt3a level is elevated with extinction training (such as with Rec+Ext protocol), modification to the existing memory occurs and as a consequence extinction does not act as a separate mechanism or form a new memory; but if Dnmt3a level is unaltered with extinction training, a separate extinction memory is formed which acts to suppress or compete with the existing memory.”

The relevant difference between humans and lab 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 exposure therapy and manipulating Dnmt3a levels.

https://www.nature.com/articles/s41598-018-23533-w “Dnmt3a in the dorsal dentate gyrus is a key regulator of fear renewal”

This dietary supplement is better for depression symptoms than placebo

gettingwell4 5+ stars Premium, Cerebrum, Dopamine, Epigenetics, Glutamate, Hippocampus, Limbic system, Neurochemicals, Serotonin, Stress, Testosterone , , ,

This 2018 Italy/UK meta-analysis subject was the use of dietary supplement acetyl-L-carnitine to treat depression symptoms:

“Deficiency of acetyl-L-carnitine (ALC) appears to play a role in the risk of developing depression, indicating dysregulation of fatty acids transport across the inner membrane of mitochondria. However, the data regarding ALC supplementation in humans are limited. We thus conducted a systematic review and meta-analysis investigating the effect of ALC on depressive symptoms across randomized controlled trials (RCTs).

Pooled data across nine RCTs (231 treated with ALC versus 216 treated with placebo and 20 no intervention) showed that ALC significantly reduced depressive symptoms.

In these nine RCTs, the majority of the studies used 3 grams of ALC as intervention.

In three RCTs comparing ALC versus antidepressants (162 for each group), ALC demonstrated similar effectiveness compared with established antidepressants [fluoxetine (Prozac), duloxetine (Cymbalta), amisulpride (Solian) respectively below] in reducing depressive symptoms. In these latter RCTs, the incidence of adverse effects was significantly lower in the ALC group [79%] than in the antidepressant group.

Subgroup analyses suggested that ALC was most efficacious in older adults. Future large scale trials are required to confirm/refute these findings.”

From the Methods section:

“Studies were excluded if:

  1. did not include humans;
  2. did not include a control group;
  3. did not use validated scales for assessing depression;
  4. did not report data at follow-up evaluation regarding tests assessing depression;
  5. included the use of ALC with another agent vs. placebo/no intervention.”

The Discussion section was informative regarding possible mechanisms of ALC affecting depression, pain, and linked symptoms. Several citations were of a review rather than of the original studies, however.

Research needs to proceed on to investigate therapies that address ultimate causes for depression and pain. Researchers and sponsors shouldn’t stop at just symptoms and symptom relief, notwithstanding the requirement from a statistical point of view for “future large scale trials.”

Here are other acetyl-L-carnitine topics I’ve curated:

https://journals.lww.com/psychosomaticmedicine/Citation/2018/02000/Acetyl_L_Carnitine_Supplementation_and_the.4.aspx “Acetyl-L-Carnitine Supplementation and the Treatment of Depressive Symptoms: A Systematic Review and Meta-Analysis” (not freely available)

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.

Maternal obesity causes fetal liver damage

gettingwell4 2-3 stars Required further work, Epigenetics, Stress ,

This 2018 US baboon study was on fetal effects from maternal obesity before and during pregnancy:

“Approximately 64% of women of childbearing age in the USA [are] overweight or obese. The baboon is a well-characterized animal model sharing many physiological, metabolic, and genetic characteristics with humans allowing direct translation of findings to human pregnancy.

Our study shows that fetal exposure to the MO [maternal obesity] intrauterine environment results in dysregulation of fetal hepatic genes central to metabolism.

These findings were further supported by identification of miRNAs that were inversely expressed with key genes in these pathways..suggest important early molecular mechanisms by which MO programs fetal hepatic lipid metabolism.

Future studies are required in MO post-natal offspring to determine the extent to which the fetal phenotype persists, and the degree to which this increases offspring risk of cardiometabolic disorders in later life.”

The study provided many measurements that may be relevant to humans. Other consequential measurements were missing that may have made the study’s findings even more applicable to humans:

  • No placental measurements other than weight. The organ through which the fetus received its nutrients, signaled its needs, modulated its growth rate, and developed its organs, was only measured by weight?
  • No other epigenetic analyses such as DNA methylation and histone modifications.

Were these omitted due to limited resources?

http://onlinelibrary.wiley.com/doi/10.1113/JP275422/pdf “Primate fetal hepatic responses to maternal obesity: epigenetic signalling pathways and lipid accumulation”

What will it take for childhood trauma research to change paradigms?

gettingwell4 0-1 star Wasted resources, Brain development, Cortisol, Epigenetics, Hippocampus, Hypothalamus, Limbic system, Memory, Neurochemicals, Serotonin, Stress , , ,

This 2018 German human study found:

“DNA methylation in a biologically relevant region of NR3C1-1F [glucocorticoid receptor gene] moderates the specific direction of HPA-axis dysregulation (hypo- vs. hyperreactivity) in adults exposed to moderate-severe CT [childhood trauma].

In contrast, unexposed and mildly-moderately exposed individuals displayed moderately sized cortisol stress responses irrespective of NR3C1-1F DNA methylation. Contrary to some prior work, however, our data provides no evidence for a direct association of CT and NR3C1-1F DNA methylation status.”

The study was an example of why researchers investigating the lasting impacts of human traumatic experiences won’t find causes, effects, and productive therapies until their paradigms change.

1. Limited subject histories

A. Why weren’t the subjects asked for historical information about their parents, grandparents, and great-grandparents?

The researchers had no problem using animal studies to guide the study design, EXCEPT for animal studies of the etiologic bases of intergenerational and transgenerational transmission of biological and behavioral phenotypes. Just the approximate places and dates of three generations of the German subjects’ ancestors’ births, childhoods, adolescences, and early adulthoods may have provided relevant trauma indicators.

B. Why are studies still using the extremely constrained Childhood Trauma Questionnaire? Only one CTQ aspect was acknowledged as a study design limitation:

“Our findings rely on retrospective self-report measures of CT, which could be subject to bias.”

But bias was among the lesser limiting factors of the CTQ.

The study correlated epigenetic changes with what the subjects selectively remembered, beginning when their brains developed sufficient cognitive functionalities to put together the types of memories that could provide CTQ answers – around age four. The basic problem that kept the CTQ from discovering likely most of the subjects’ traumatic experiences causing epigenetic changes was that these experiences predated the CTQ’s developmental starting point:

  1. A human’s conception through prenatal period is when both the largest and the largest number of epigenetic changes occur, and is when our susceptibility and sensitivity to our environment is greatest;
  2. Birth through infancy is the second-largest; and
  3. Early childhood through the age of three is the third largest.

CTQ self-reports were – at best – evidence of experiences after age three, distinct from the  experience-dependent epigenetic changes since conception. If links existed between the subjects’ early-life DNA methylation and later-life conditions, they weren’t necessarily evidenced by CTQ answers about later life that can’t self-report relevant early-life experiences that may have caused DNA methylation.

2. Limited subject selection

The researchers narrowed down the initial 622 potential subjects to the eventual 200 subjects aged 18 to 30. An exclusion criteria that was justified as eliminating confounders led to this limitation statement:

“Our results might be based on a generally more resilient sample as we had explicitly excluded individuals with current or past psychopathology.”

Was it okay for the researchers to assert:

“Exposure to environmental adversity such as childhood trauma (CT) affects over 10% of the Western population and ranges among the best predictors for psychopathology later in life.”

but not develop evidence for the statement by letting people who may have been already affected by age 30 and received treatment participate in the study?

Was the study design so fragile that it couldn’t adjust to the very people who may be helped by the research findings?

3. Limited consequential measurements

The current study design conformed to previous studies’ protocols. The researchers chose cortisol and specific DNA methylation measurements.

A. Here’s what Sex-specific impacts of childhood trauma had to say about 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.”

The researchers knew or should have known all of the above since this quotation came from a review.

B. What other consequential evidence for prenatal, infancy, and early childhood experience-dependent epigenetic changes can be measured? One overlooked area was including human emotions as evidence.

There are many animal studies from which to draw inferences about human emotions. There are many animal models of creating measurable behavioral and biological phenotypes of human emotion correlates, with many methods, including manipulating environmental variables during prenatal, infancy, and early childhood periods.

Studies that take detailed histories may arrive at current emotional evidence for human subjects’ earliest experience-dependent changes. Researchers who correlate specific historical environments and events, stress measurements, and lasting human emotions expressed as “I’m all alone” and “No one can help me” will better understand causes and effects.

CTQ answers weren’t sufficiently detailed histories.

4. Limited effective treatments and therapies

The current study only addressed this area in the final sentence:

“Given their potential reversibility, uncovering epigenetic contributions to differential trajectories following childhood adversity may serve the long-term goal of delivering personalized prevention strategies.”

Researchers – if your paradigms demonstrate these characteristics:

  • Why are you spending your working life in efforts that can’t make a difference?
  • Aren’t your working efforts more valuable than that?
  • What else could you investigate that could make a difference in your field?

I hope that researchers will value their professions enough to make a difference with their expertise. And that sponsors won’t thwart researchers’ desires for difference-making science by putting them into endless funding queues.

http://www.psyneuen-journal.com/article/S0306-4530(17)31355-0/pdf “Glucocorticoid receptor gene methylation moderates the association of childhood trauma and cortisol stress reactivity” (not freely available)

Cell senescence and DNA methylation

gettingwell4 2-3 stars Required further work, Epigenetics, Stress, Telomeres ,

This 2018 Baltimore cell study found:

“Based on similarities in overall methylation patterns in replicative senescence and cancers, it is hypothesized that tumor-promoting DNA methylation in cancers derives from cells escaping senescence.

We show that the tumor-associated methylation changes evolve independently of senescence and are pro-survival events with functional implications contrasting that in senescence.

In our analyses, although overall global gains and losses in DNA methylation are similar, at individual genomic regions the methylation patterns are very different for senescence versus transformation.”

https://www.sciencedirect.com/science/article/pii/S1535610818300084 “DNA Methylation Patterns Separate Senescence from Transformation Potential and Indicate Cancer Risk” (not freely available)

I hesitated to use the study’s main graphic:
because the “Stochastic” labeling of the upper branch didn’t represent the vector’s meaning. The In Brief and the Summary sections contributed to the misrepresentation by stating:

“transformation-associated methylation changes arise stochastically.”

which wasn’t the study’s main finding:

“Our data outlined in the above sections strongly suggest against this senescence bypass hypothesis.”

Although the experimental design and methods evoked randomness:

“Immortalization on the path to malignant transformation involves stochastic epigenetic patterns from which cells contributing to transformation may evolve.”

the graphic’s upper branch vector represented the cells’ evolutionary responses. The Significance section best characterized what the study found:

“Tumor-associated methylation changes evolve independently of senescence and are pro-survival events.”

Would anyone at John Hopkins argue, as the graphic’s upper branch labeling suggested, that cellular aging is a predominantly random process? NO!

1. Epigenetics research and evolution promoted understanding the graphic’s upper branch vector:

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

2. The current study provided another data point about the uselessness of convenient but non-etiologic, inconsequential measurements of global methylation:

“Although overall global gains and losses in DNA methylation are similar, at individual genomic regions the methylation patterns are very different.”

3. The current study was congruent with the below finding of Using an epigenetic clock to distinguish cellular aging from senescence regarding the differentiation of cellular aging from senescence:

“Cellular ageing is distinct from cellular senescence and independent of DNA damage response and telomere length.”

Obtaining convictions with epigenetic statistics?

gettingwell4 < 0 Detracted from science, Epigenetics ,

This 2018 Austrian review subject was forensic applications of epigenetic clock methodologies:

“The methylation-sensitive analysis of carefully selected DNA markers (CpG sites) has brought the most promising results by providing prediction accuracies of ±3–4 years, which can be comparable to, or even surpass those from, eyewitness reports. This mini-review puts recent developments in age estimation via (epi)genetic methods in the context of the requirements and goals of forensic genetics and highlights paths to follow in the future of forensic genomics.”

The point of forensic analysis techniques should be to find the truth about an individual. Doesn’t the principle of “All presumptive evidence of felony should be admitted cautiously; for the law holds it better that ten guilty persons escape, than that one innocent party suffer” still hold?

The methods’ limitations weren’t discussed. Here are some concepts not mentioned in the review:

1) Summary statistics that describe a group or population NEVER necessarily describe an individual member.

For an epigenetic clock methodology example, take a look at Figure 2A in Using an epigenetic clock to assess liver disease. 16 of the 18 individual age acceleration estimates of the control group subjects aren’t close to the median value!

2) The reviewer outlined basic DNA methylation analysis:

“The most commonly pursued approach for analysing CpG sites is sequence analysis of bisulfite-converted DNA, during which single-stranded genomic DNA is treated with sodium bisulfite that deaminates unmethylated cytosine to uracil, while methylated cytosine remains unaffected.

With increasing age, not only genome-wide DNA hypomethylation has been observed but also regional DNA hypermethylation of CpG islands.”

The basic limitation of this analysis wasn’t mentioned, but A study of DNA methylation and age said:

“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.”

3) Another omission was that the numbers and types of targets in the discussed DNA methylation technique were severely limited per The primary causes of individual differences in DNA methylation are environmental factors:

“A main limitation with studies using the Illumina 450 K array is that the platform only covers ~1.5 % of overall genomic CpGs, which are biased towards promoters and strongly underrepresented in distal regulatory elements, i.e., enhancers.

The reviewer didn’t provide convincing justifications for using gene expression profiling to obtain convictions. Was it too much to expect a mini-review to offer a balanced view of using epigenetic age estimation in forensic analyses?

https://www.karger.com/Article/FullText/486239 “Age Estimation with DNA: From Forensic DNA Fingerprinting to Forensic (Epi)Genomics: A Mini-Review”

Using an epigenetic clock to assess liver disease

gettingwell4 4-5 stars Advanced knowledge, Epigenetics ,

This 2018 UC San Diego human study investigated the capability of the epigenetic clock methodology to detect biological aging with nonalcoholic steatohepatitis (NASH) patients:

“The ability to measure a surrogate marker of liver aging from a peripheral blood sample has broad implications for assessing clinically “silent” chronic diseases, such as NASH, and, potentially, their response to interventions.

In the current study, we validate the utility of the Horvath clock in measuring age acceleration in a defined cohort of NASH patients with moderate to severe liver fibrosis.”

The study demonstrated several aspects of age acceleration and disease conditions, including:

– Use of clinical trial data.

“This study, however, included patients who were part of a clinical trial in which protocol-obtained biopsies were read by a central pathologist (ZG) and morphometric quantification of collagen standardized.”

– Continuous measures were more relevant than “Stage X” measures.

“The findings in the current work are in contrast to an earlier study that found no association of DNAm with the NAFLD activity score or stage of liver fibrosis in patients with NASH. Importantly, that study assessed liver fibrosis based on conventional histological staging only, using the ordinal METAVIR classification. Similarly, we also found no difference in age acceleration between patients with stage 2 and 3 fibrosis according to the NASH Clinical Research Network (CRN) classification.

On the contrary, by evaluating two continuous measures of fibrosis (hepatic collagen content by morphometry and the serum ELF test), which have a greater dynamic range than traditional histological staging, we found that patients with higher age acceleration have increased hepatic fibrosis.”

– Causalities may not necessarily be ascribed.

“Although these reports establish a potential relationship between fibrosis and specific epigenetic modifications, targeted individual CpG sites may not accurately reflect the complex interaction between causal and compensatory measures in chronic diseases such as NASH.”

https://insight.jci.org/articles/view/96685 “DNA methylation signatures reflect aging in patients with nonalcoholic steatohepatitis”

Epigenetic study methodologies improved in 2017

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Beliefs, Brain development, Cerebrum, Epigenetics, Limbic system, Stress , , , , ,

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.”

What’s an appropriate exercise recovery time?

gettingwell4 4-5 stars Advanced knowledge, Stress

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”

Do you have your family’s detailed medical histories?

gettingwell4 4-5 stars Advanced knowledge, Brain development, Cerebrum, Cortisol, Epigenetics, Hypothalamus, Limbic system, Neurochemicals, Stress , , , , , ,

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?

gettingwell4 < 0 Detracted from science, Beliefs, Brain development, Cerebrum, Epigenetics, Stress , , , ,

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”

An update on brain zapping

gettingwell4 2-3 stars Required further work, Cerebrum, Limbic system, Thalamus ,

This 2017 general-audience article entitled Ultrasound for the brain provided a hyped update on brain zapping:

“Ultrasound could potentially treat other movement disorders, as well as depression, anxiety and a host of intract­able neuropsychiatric disorders..

This could be a breakthrough..

Researchers hope one day to help people with neuropsychiatric conditions by repairing or resetting the relevant neural pathways..

The potential advantages, especially for deep brain areas, are huge..”

Though not the main thrust of the article, another potential use of ultrasound would be to activate drugs delivered to a specific area, as this image portrays:

Vanderbilt University was again at the forefront of brain zapping, as noted in What’s an appropriate control group for a schizophrenia study? for example. I hope the disclosures for subjects participating in Vanderbilt’s brain-zapping studies made it clear that:

“At high intensities, such as those used to relieve essential tremor, ultrasound’s effects are largely thermal: the tissue heats up and cells die.”

Comments are disabled because this post has somehow become a target for spammers. Readers can click the above control group link to comment.

“Transgenerationally” inherited epigenetic effects of fetal alcohol exposure

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

The fourth paper of Transgenerational epigenetic inheritance week was a 2016 German rodent study of of improperly-termed “transgenerational” epigenetic effects of alcohol:

“We investigated 2 generations of offspring born to alcohol-treated mothers. Here, we show that memory impairment and reduced synthesis of acetylcholine occurs in both F1 (exposed to ethanol in utero) and F2 generation (never been exposed to ethanol). Effects in the F2 generation are most likely consequences of transgenerationally transmitted epigenetic modifications in stem cells induced by alcohol.

The results further suggest an epigenetic trait for an anticholinergic endophenotype associated with cognitive dysfunction which might be relevant to our understanding of mental impairment in neurodegenerative disorders such as Alzheimer’s disease and related disorders.”

F0 generation mothers modeled human fetal alcohol syndrome. They were exposed to ethanol gradually up to 20%, then mated. The 20% ethanol intake level was maintained until the F1 generation pups were born, then gradually diminished to 0%. After a ten-day wait, an eight-week handling and shaping period started, followed by five weeks of behavioral testing.

The F1 children and F2 grandchildren started an eight-week handling and shaping period after young adulthood, followed by five weeks of behavioral testing. The F1 children were mated after behavioral testing.

The F0 parents showed no significant differences in working memory and reference memory compared with controls. Both the F1 children and F2 grandchildren were significantly impaired in the same tests compared with controls, with the F1 children performing worse than the F2 grandchildren. No sex-dependent differences were noted.

After behavioral impairments due to intergenerational epigenetic modifications were established, the F2 grandchildren received treatments to ascertain the contribution of cholinergic dysfunction in their behavioral impairments. It was confirmed, as an acetylcholine esterase inhibitor that crosses the blood-brain barrier almost completely erased working-memory and reference-memory performance deficits.

Items in the Discussion section included:

  • A dozen studies from 2014-2016 were cited for epigenetic mechanisms of inheritance stemming from parental alcohol consumption; and
  • Transgenerational inheritance of alcohol-induced neurodevelopmental deficits may involve epigenetic mechanisms that are resistant to developmental clearance.

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 F3 great-grandchildren was needed in order to establish transgenerational vs. intergenerational results. A F3 generation necessarily controls for the variable of F2 direct germline exposure.

http://www.neurobiologyofaging.org/article/S0197-4580(16)30303-7/pdf “Transgenerational transmission of an anticholinergic endophenotype with memory dysfunction” (not freely available)

Transgenerational pathological traits induced by prenatal immune activation

gettingwell4 2-3 stars Required further work, Amygdala, Brain development, Epigenetics, Glutamate, Immune system, Limbic system, Neurochemicals, Stress , , , , , , ,

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

gettingwell4 2-3 stars Required further work, Amygdala, Anterior cingulate cortex, Brain development, Brainstem, Cerebrum, Cortisol, Dopamine, Epigenetics, Glutamate, Hippocampus, Hypothalamus, Limbic system, Locus coeruleus, Lower brain, Memory, Neurochemicals, Oxytocin, Serotonin, Stress , , , , , , , , , , ,

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)