Pre-implantation alcohol exposure induces lasting sex-specific DNA methylation programming errors in the developing forebrain

Background

Prenatal alcohol exposure is recognized for altering DNA methylation profiles of brain cells during development, and to be part of the molecular basis underpinning Fetal Alcohol Spectrum Disorder (FASD) etiology.  However, we have negligible information on the effects of alcohol exposure during pre-implantation, the early embryonic window marked with dynamic DNA methylation reprogramming, and on how this may rewire the brain developmental program.

Results

Using a pre-clinical in vivo mouse model, we show that a binge-like alcohol exposure during pre-implantation at the 8-cell stage leads to surge in morphological brain defects and adverse developmental outcomes during fetal life. Genome-wide DNA methylation analyses of fetal forebrains uncovered sex-specific alterations, including partial loss of DNA methylation maintenance at imprinting control regions, and abnormal de novo DNA methylation profiles in various biological pathways (e.g., neural/brain development).

Conclusion

These findings support that alcohol-induced DNA methylation programming deviations during pre-implantation could contribute to the manifestation of neurodevelopmental phenotypes associated with FASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01151-0.

Developmental genome-wide DNA methylation asymmetry between mouse placenta and embryo

In early embryos, DNA methylation is remodelled to initiate the developmental program but for mostly unknown reasons, methylation marks are acquired unequally between embryonic and placental cells. To better understand this, we generated high-resolution DNA methylation maps of mouse mid-gestation (E10.5) embryo and placenta. We uncovered specific subtypes of differentially methylated regions (DMRs) that contribute directly to the developmental asymmetry existing between mid-gestation embryonic and placental DNA methylation patterns. We show that the asymmetry occurs rapidly during the acquisition of marks in the post-implanted conceptus (E3.5-E6.5), and that these patterns are long-lasting across subtypes of DMRs throughout prenatal development and in somatic tissues. We reveal that at the peri-implantation stages, the de novo methyltransferase activity of DNMT3B is the main driver of methylation marks on asymmetric DMRs, and that DNMT3B can largely compensate for lack of DNMT3A in the epiblast and extraembryonic ectoderm, whereas DNMT3A can only partially compensate in the absence of DNMT3B. However, as development progresses and as DNMT3A becomes the principal de novo methyltransferase, the compensatory DNA methylation mechanism of DNMT3B on DMRs becomes less effective.

Feasibility of ultra low-dose coronary computed tomography angiography

There is an urgent need to develop new protocols to reduce radiation dose of coronary computed tomography angiography (CTA). The aim of this pilot study was to demonstrate the feasibility of an ultra-low dose CTA scanning.

Stability of the human sperm DNA methylome to folic acid fortification and short-term supplementation

STUDY QUESTION

Do short-term and long-term exposures to low-dose folic acid supplementation alter DNA methylation in sperm?

SUMMARY ANSWER

No alterations in sperm DNA methylation patterns were found following the administration of low-dose folic acid supplements of 400 μg/day for 90 days (short-term exposure) or when pre-fortification of food with folic acid and post-fortification sperm samples (long-term exposure) were compared.

WHAT IS KNOWN ALREADY

Excess dietary folate may be detrimental to health and DNA methylation profiles due to folate's role in one-carbon metabolism and the formation of S-adenosyl methionine, the universal methyl donor. DNA methylation patterns are established in developing male germ cells and have been suggested to be affected by high-dose (5 mg/day) folic acid supplementation.

STUDY DESIGN, SIZE, DURATION

This is a control versus treatment study where genome-wide sperm DNA methylation patterns were examined prior to fortification of food (1996-1997) in men with no history of infertility at baseline and following 90-day exposure to placebo (n = 9) or supplement containing 400 μg folic acid/day (n = 10). Additionally, pre-fortification sperm DNA methylation profiles (n = 19) were compared with those of a group of post-fortification (post-2004) men (n = 8) who had been exposed for several years to dietary folic acid fortification.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Blood and seminal plasma folate levels were measured in participants before and following the 90-day treatment with placebo or supplement. Sperm DNA methylation was assessed using the whole-genome and genome-wide techniques, MassArray epityper, restriction landmark genomic scanning, methyl-CpG immunoprecipitation and Illumina HumanMethylation450 Bead Array.

MAIN RESULTS AND THE ROLE OF CHANCE

Following treatment, supplemented individuals had significantly higher levels of blood and seminal plasma folates compared to placebo. Initial first-generation genome-wide analyses of sperm DNA methylation showed little evidence of changes when comparing pre- and post-treatment samples. With Illumina HumanMethylation450 BeadChip arrays, no significant changes were observed in individual probes following low-level supplementation; when compared with those of the post-fortification cohort, there were also few differences in methylation despite exposure to years of fortified foods.

LARGE SCALE DATA

Illumina HumanMethylation450 BeadChip data from this study have been submitted to the NCBI Gene Expression Omnibus under the accession number GSE89781.

LIMITATIONS, REASONS FOR CAUTION

This study was limited to the number of participants available in each cohort, in particular those who were not exposed to early (pre-1998) fortification of food with folic acid. While genome-wide DNA methylation was assessed with several techniques that targeted genic and CpG-rich regions, intergenic regions were less well interrogated.

WIDER IMPLICATIONS OF THE FINDINGS

Overall, our findings provide evidence that short-term exposure to low-dose folic acid supplements of 400 μg/day, over a period of 3 months, a duration of time that might occur during infertility treatments, has no major impact on the sperm DNA methylome.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by a grant to J.M.T. from the Canadian Institutes of Health Research (CIHR: MOP-89944). The authors have no conflicts of interest to declare.

Downstream clinical consequences of stress cardiovascular magnetic resonance based on appropriate use criteria

BACKGROUND

Appropriate use criteria (AUC) have been developed by professional organizations as a response to the rising costs of imaging, with the goal of optimizing test-patient selection. Consequently, the AUC are now increasingly used by third-party-payers to assess reimbursement. However, these criteria were created by expert consensus and have not been systematically assessed for CMR. The aim of this study was to determine the rates of abnormal stress-CMR and subsequent downstream utilization of angiography and revascularization procedures based on the most recent AUC.

METHODS

300 consecutive patients referred for CMR-stress testing were prospectively enrolled. Two cardiologists reviewed all clinical information before the CMR-stress test and classified the test as "appropriate', "maybe appropriate" or "rarely appropriate" according to the 2013 AUC. Patients were followed for 2 months for the primary outcomes of coronary angiography and/or revascularization.

RESULTS

49.7% of stress CMRs were appropriate, 36.7% maybe appropriate, and 13.6% rarely appropriate. Ischemia was significantly more likely to be seen in the appropriate (18.8%) or maybe appropriate groups (21.8%) than the rarely appropriate group (4.8%) (p = 0.030 and p = 0.014 respectively). Referral for cardiac catheterization was not significantly different in the appropriate (10.1%) and maybe appropriate groups (10.0%) compared to the rarely appropriate group (2.4%) (p = 0.119 and p = 0.127 respectively). No patients undergoing catheterization in the rarely appropriate group went on to require revascularization, in contrast to 53.3% of the appropriate vs 36.4% of the maybe appropriate patients (p = 0.391). Presence of ischemia led to referral for cardiac catheterization in 50.0% of the appropriate group vs 33.3% of the maybe appropriate group (p = 0.225); in contrast to none of the rarely appropriate group.

CONCLUSIONS

The great majority of tests were classified as appropriate or maybe appropriate. Downstream cardiac catheterization rates were similar in all 3 groups. However, rarely appropriate studies never required revascularization, suggesting suboptimal resource utilization. Studies classified as maybe appropriate had similar rates of abnormal findings and led to similar rates of downstream catheterization and revascularization as those that were deemed appropriate. This suggests that consideration could be given to upgrading some of the common maybe appropriate indications to the appropriate category.

Temporal and Geographic Clustering of Polyomavirus-Associated Olfactory Tumors in 10 Free-Ranging Raccoons (Procyon lotor)

Reports of primary nervous system tumors in wild raccoons are extremely rare. Olfactory tumors were diagnosed postmortem in 9 free-ranging raccoons from 4 contiguous counties in California and 1 raccoon from Oregon within a 26-month period between 2010 and 2012. We describe the geographic and temporal features of these 10 cases, including the laboratory diagnostic investigations and the neuropathologic, immunohistochemical, and ultrastructural characteristics of these tumors in the affected animals. All 9 raccoons from California were found within a localized geographic region of the San Francisco Bay Area (within a 44.13-km radius). The tight temporal and geographic clustering and consistent anatomic location in the olfactory system of tumor types not previously described in raccoons (malignant peripheral nerve sheath tumors and undifferentiated sarcomas) strongly suggest either a common cause or a precipitating factor leading to induction or potentiation of neuro-oncogenesis and so prompted an extensive diagnostic investigation to explore possible oncogenic infectious and/or toxic causes. By a consensus polymerase chain reaction strategy, a novel, recently reported polyomavirus called raccoon polyomavirus was identified in all 10 tumors but not in the normal brain tissue from the affected animals, suggesting that the virus might play a role in neuro-oncogenesis. In addition, expression of the viral protein T antigen was detected in all tumors containing the viral sequences. We discuss the potential role of raccoon polyomavirus as an oncogenic virus.

Stress fracture risk factors in basic combat training

This study examined demographic and physical risk factors for stress fractures in a large cohort of basic trainees. New recruits participating in US Army BCT from 1997 through 2007 were identified, and birth year, race/ethnicity, physical characteristics, body mass index, and injuries were obtained from electronic databases. Injury cases were recruits medically diagnosed with inpatient or outpatient stress fractures. There were 475 745 men and 107 906 women. Stress fractures incidences were 19.3 and 79.9 cases/1 000 recruits for men and women, respectively. Factors that increased stress fracture risk for both men and women included older age, lower body weight, lower BMI, and race/ethnicity other than black. Compared to Asians, those of white race/ethnicity were at higher stress fractures risk. In addition, men, but not women, who were taller or heavier were at increased stress fracture risk. Stress fracture risk generally increased with age (17-35 year range) at a rate of 2.2 and 3.9 cases/1 000 recruits per year for men and women, respectively. This was the largest sample of military recruits ever examined for stress fractures and found that stress fracture risk was elevated among recruits who were female, older, had lower body weight, had lower BMI, and/or were not of black race/ethnicity.

Inguinal lymph node metastasis of colon cancer

We present a case of adenocarcinoma of colon with unusual metastasis to inguinal lymph nodes. Our patient is a young male with bilateral inguinal lymphadenopathy, bone pains, and jaundice who presented as carcinoma of unknown primary. He was diagnosed as widely metastatic adenocarcinoma of colon for which he received chemotherapy and has had a good response to the treatment.

Abstract 436: Assessing Statin Therapy and Lipid Profile Goals 6 Months After Percutaneous Coronary Intervention at a Veterans Hospital

Background: Lipid lowering therapy is an established core measure of secondary prevention in coronary artery disease (CAD) management. The National Cholesterol Education Program - Adult treatment panel III (NCEP-ATP III) advises a minimum LDL level less than 100 mg/dL in patients with CAD and a recommended LDL less than 70 mg/dL for high risk patients. Statins remain the preferred agent for LDL reduction.

Methods: We conducted a retrospective, observational study on all patients undergoing PCI at an urban Veterans Hospital from September 2004 to January 2011. Statin use and lipid profiles at 6 months post-PCI were compared to pre-PCI values.

Results: A total of 933 unique patients had PCI during the study period. The mean total cholesterol decreased 18 mg/dL and the mean LDL decreased 15 mg/dL during 6 months follow-up (p< 0.001) (refer to table). The mean HDL did not differ significantly. The percent of patients at NCEP-ATP III guideline’s goal of LDL < 100 mg/dL increased from 58% pre-PCI to 74% post-PCI. Goal LDL < 70 mg/dL increased from 22 to 31% at 6 months. The use of statins increased from 69% to 89%.

Conclusion: There were significant improvements in total cholesterol and LDL values at six months post-PCI, as well as the percentage of patients who met the NCEP-ATP III recommended goal of LDL cholesterol less than 100 mg/dL and the suggested goal of 70 mg/dL. At six months, there was an increase usage of statin therapy.

Abstract 137: Comparing Blood Pressure Control in Diabetic Versis Nondiabetic Veterans Following Percutaneous Coronary Intervention

Background: As per the US Joint National Committee VII (JNC-7) recommendations, patients with known underlying coronary artery disease and diabetes should have goal blood pressures (BP) of systolic (SBP) <130 and diastolic (DBP) <80 to decrease morbidity and mortality associated with cardiovascular disease. In addition to lifestyle modification, these goals can be attained by use of multiple classes of drugs including beta-blockers (BB), angiotensin-converting-enzyme inhibitors/angiotensin receptor blockers (ACE-I/ARB), calcium channel blockers (CCB), diuretics and nitrates.

Methods: We conducted a retrospective cohort study focusing on the attainment of the JNC-7 guidelines, comparing outcomes between 355 diabetic to 580 non-diabetic patients undergoing PCI between September 2004 and January 2011 at the Jesse Brown Veterans Affairs Hospital in Chicago, IL. BP measurements and antihypertensive medications pre and post PCI at 6-month follow-up were documented.

Results: Among the diabetic population, the mean SBP decreased from 136 to 131 mmHg (p = 0.0007) and mean DBP decreased from 73 to 70 mmHg (p = 0.0005). In the non-diabetics, the mean SBP decreased from 133 to 127 mmHg (p < 0.0001) and the mean DBP decreased from 73 to 70 mmHg (p < 0.0001). With regards to JNC-7 guidelines, the percent of diabetics at SBP goal increased from 39% to 49% (p = 0.0053) and percent at DBP goal increased from 73% to 82% (p = 0.0098). In non-diabetics, percent at goal for SBP increased from 45% to 57% (p < 0.0001) and percent at DBP goal increased from 68% to 76% (p = 0.0009). Among diabetics, there was a statistically significant (p <0.0001) increase in use of BB from 79% to 92%. In non-diabetics, there was a statistically significant (p <0.0001) increase in use of BB from 66% to 87% and ACE-I/ARB from 51% to 70%.

Conclusions: In both groups undergoing PCI, SBP and DBP improved with more patients achieving JNC-7 targets. Among diabetics, there was a significant increase in utilization of BB. Among non-diabetics, there was a significant increase in utilization of BB and ACE-I/ARB.

Abstract 188: Blood Pressure Control in Veterans following Percutaneous Coronary Intervention

Background: As per the US Joint National Committee VII (JNC-7) recommendations, patients with known underlying CAD and percutaneous coronary intervention (PCI) should have goal blood pressures of systolic <130 and diastolic <80. In addition to lifestyle modification, these goals can be attained by use of multiple classes of drugs including beta-blockers (BB), angiotensin agonists (ACE-I/ARB), calcium channel blockers (CCB), diuretics and nitrates.

Methods: We conducted a retrospective cohort study in 935 consecutive patients undergoing PCI between September 2004 and January 2011 at the Jesse Brown Veterans Administration Hospital in Chicago, IL. Blood pressure (BP) measurements and antihypertensive medications pre and post PCI at 6-month follow-up were documented.

Results: Over the 6-month follow-up period, mean systolic blood pressure (SBP) decreased from 134 to 129 mmHg (p < 0.0001) and mean diastolic blood pressure (DBP) decreased from 73 to 70mmHg (p < 0.0001). As per JNC-7 guidelines, the percent of patients who reached SBP goals increased from 43 to 52% (403 to 485 of 935) and with DBP goals rose from 70 to 76% (655 to 706 of 935). At 6-month follow-up, there was a statistically significant increase in the utilization of beta-blockers, ACE-I/ARBs, and nitrates. (TABLE)

Conclusions: In this group of patients undergoing PCI, both systolic and diastolic blood pressure improved with more patients achieving JNC-7 targets. There was a significant increase in utilization in evidence-based medication.

Abstract 81: Lipid Profiles in Minority and Non-Minority Veterans following Percutaneous Coronary Intervention

Background: Lipid lowering therapy is an established core measure of secondary prevention in coronary artery disease (CAD) management. The National Cholesterol Education Program - Adult treatment panel III (NCEP ATPIII) guidelines recommend a goal low density lipoprotein (LDL) level less than 100 mg/dL for CAD management. Statins remain the preferred agent for LDL reduction. It is unclear whether race plays a role in lipid control.

Methods: We conducted a retrospective, observational study on all patients undergoing PCI at an urban Veterans Hospital from September 2004 to January 2011. Statin use and lipid profiles at 6 months post-PCI were compared to pre-PCI values between minorities and non-minorities.

Results: A total of 937 patients (59% minorities) were analyzed. The mean total cholesterol and mean LDL decreased at six-month follow-up in both groups. The mean total cholesterol decreased 18 mg/dL in both minority and non-minority groups. The mean LDL decreased by 11 mg/dL in the minority group and by 13 mg/dL in the non-minority group (p<0.001) (refer to table). The percent of patients at LDL goals of <100 mg/dL pre-PCI and at six month follow-up increased from 54% to 72% in the minority group and from 63% to 76% in the non-minority group. The percent of patients on a statin pre-PCI and at six month follow-up increased from 70% to 90% in the minority group and 73% to 87% in the non-minority group. There was no significant difference in lipid profiles and statin adherence between racial groups.

Conclusion: There were improvements in both total cholesterol and LDL values at six months post-PCI in both the minority and non-minority groups. There were also improvements in the percentage of patients who met the ATP III recommended goal of LDL cholesterol less than 100mg/dL at six months in both groups. At six months, there was also an increase in usage of statin therapy in both groups. Race did not appear to play a significant role in lipid management.

The effects of modulating eNOS activity and coupling in ischemia/reperfusion (I/R)

The in vivo role of endothelial nitric oxide synthase (eNOS) uncoupling mediating oxidative stress in ischemia/reperfusion (I/R) injury has not been well established. In vitro, eNOS coupling refers to the reduction of molecular oxygen to L-arginine oxidation and generation of L-citrulline and nitric oxide NO synthesis in the presence of an essential cofactor, tetrahydrobiopterin (BH(4)). Whereas uncoupled eNOS refers to that the electron transfer becomes uncoupled to L-arginine oxidation and superoxide is generated when the dihydrobiopterin (BH(2)) to BH(4) ratio is increased. Superoxide is subsequently converted to hydrogen peroxide (H(2)O(2)). We tested the hypothesis that promoting eNOS coupling or attenuating uncoupling after I/R would decrease H(2)O(2)/increase NO release in blood and restore postreperfused cardiac function. We combined BH(4) or BH(2) with eNOS activity enhancer, protein kinase C epsilon (PKC ε) activator, or eNOS activity reducer, PKC ε inhibitor, in isolated rat hearts (ex vivo) and femoral arteries/veins (in vivo) subjected to I(20 min)/R(45 min). When given during reperfusion, PKC ε activator combined with BH(4), not BH(2), significantly restored postreperfused cardiac function and decreased leukocyte infiltration (p < 0.01) while increasing NO (p < 0.05) and reducing H(2)O(2) (p < 0.01) release in femoral I/R veins. These results provide indirect evidence suggesting that PKC ε activator combined with BH(4) enhances coupled eNOS activity, whereas it enhanced uncoupled eNOS activity when combined with BH(2). By contrast, the cardioprotective and anti-oxidative effects of the PKC ε inhibitor were unaffected by BH(4) or BH(2) suggesting that inhibition of eNOS uncoupling during reperfusion following sustained ischemia may be an important mechanism.

Abstract P338: Adverse Outcomes Following Percutaneous Coronary Intervention in Insulin Dependent and Non-Insulin Dependent Diabetes Mellitus

Background: ACC guidelines suggests late outcomes in diabetic patients after percutaneous coronary intervention (PCI) are similar to non-diabetics if the hgbA1C can be maintained less than 7.0%. To achieve this level of glycemic control many patients require the addition of insulin. The differences in outcomes amongst insulin dependent (IDDM) and non-insulin dependent (NIDDM) patients are not well known. We wish to analyze the cardiovascular (CV) outcomes and glycemic control of diabetic patients 6 months post PCI stratified by insulin usage.

Methods: We conducted a retrospective cohort study investigating the impact of DM on clinical outcomes in patients who underwent a PCI at a Veterans Health Institution from September 2004 to March 2009. Adverse cardiovascular outcomes (death, myocardial infarct, revascularization, cardiac hospitalization, and combined outcomes) six months post-PCI were recorded and compared in IDDM and NIDDM patients. Data pertaining to glucose levels, HgbA1C, lipids, and blood pressure were also collected.

Results: Of the 771 unique patients in our analysis, 302 had DM of which, 132(44%) were on insulin and 169(56%) were on oral medications. Although not statistically significant, in IDDM patients there was an increased rate of death, MI, cardiac hospitalization, and combined outcomes. HgbA1C and glucose values in IDDM were significantly higher pre and post-PCI.

Conclusion: Our study suggested that both IDDM and NIDDM groups had poor glycemic control, however, IDDM patients were less controlled. Although lack of power in our study may have led to our inability to detect statistically significant differences in adverse CV outcomes we can see a trend toward worse outcomes in the IDDM group. Increased attention to promote tighter glycemic control particularly among IDDM veterans is warranted. We can conclude that more attention needs to be paid to diabetics patients, especially IDDM patients, to maintain a tighter glycemic control and hence reduce adverse cardiovascular outcomes post PCI.

255EXPRESSION OF TRANSCRIPTION FACTORS PRIOR TO THE MATERNAL-TO-ZYGOTIC TRANSITION IN BOVINE EMBRYOS

During the first stages of bovine embryonic development, until the 8- to 16-cell stage, the zygote is maintained by the mRNA and proteins stored in the oocyte. New embryonic transcription is reported to begin only at the 8- to 16-cell stage even if some minor transcription is detected from the 2-cell stage. In order for this to occur, several factors are required to remodel the chromatin and activate the transcription machinery. Some regulating transcription factors are possibly present in the oocyte in their mRNA form, and their translation could enhance the maternal-to-zygotic transition (MZT). In our study, we observed the expression patterns of five transcription factors (ATF2, HMGN2, HMGB2, HUEL and MSY2) in bovine in vitro-produced embryos. Embryos were produced in vitro using selected cumulus-oocyte complexes from 3-5-mm follicles of slaughterhouse ovaries. Pooled GV or MII oocytes, and 2-, 4-, 8-cell and blastocyst-stage embryos (n=40/stage) were washed in PBS and frozen at −80°C. Each pool was spiked with 1 pg of GFP RNA containing a poly(A) tail. The RNA was extracted using the Absolutely RNA Microprep Kit (Stratagene, La Jolla, CA, USA), co-precipitated with linear acrylamide (Ambion, Austin, TX, USA) and reverse-transcribed with Omniscript (Quiagen). The quantitative amplification of the transcription factors was performed in triplicate using the equivalent of 1 oocyte or embryo per reaction on a Lightcycler (Roche, Indianapolis, IN, USA). Data were normalized with the GFP levels found in each pool and a Least-Significant-Difference method was used for statistical analysis. Immunocytochemistry studies were performed on oocytes and embryos fixed and permeabilized in a solution of paraformaldehyde and Triton X-100, and results were observed on a confocal microscope. Our results show that the transcripts of the transcription factors studied are found at higher levels in pre-MZT embryos and at lower levels in subsequent stages. For HMGN2 and MSY2, there is a decrease in mRNA during oocyte maturation. For both genes, the residual mRNA remains constant up to the 4-cell stage before another loss in transcript levels in the 8-cell stage. In the case of ATF2, HMGB2 and HUEL, the maternal transcript levels are maintained until the 4-cell stage, suggesting that the mRNA is protected from degradation until its possible translation at the MZT. These results, combined to immunolocalization of the proteins, suggest a possible implication of some of these factors in the bovine MZT.