User:Etchevers/Notebook/Conference notes/2009/09/12: Difference between revisions
| Line 109: | Line 109: | ||
• '''Sarah Tinker, CDC also.''' | |||
Women of childbearing age but non pregnant in the cohort previously described. USDA and public health service recommendations – 400 ug/day if trying to get pregnant. Some recommendations up to 800 ug/day (USPSTF where TF is task force). | |||
Women with obesity or diabetes don’t particularly increase their folic acid intake and don’t make particular population-visible efforts to take supplements – conclusion, they should, because no women of childbearing age sub-populations are really able to get to the recommendations on diet alone. | |||
''Questions:'' | |||
Tough with non-supplemented diet to get folate levels. Before supplements between 100 and 10000 years ago, was there a selective impact on the species? Was there another dietary source or were all those particular babies lost? Answer (of course): I don’t know! RCT’s were only done on synthetic folic acid. | |||
Other members of the audience chipped in: But although we think we are sophisticated in our eating habits, earlier populations may have actually eaten more appropriate food to prevent certain vitamin deficiencies, when the food itself was available. | |||
“Paleolithic diet” currently in fashion – yet would have it been up to 400 ug/day? | |||
*'''[[User:Etchevers|Heather]] 14:19, 12 September 2009 (EDT)''': | |||
<!-- ##### DO NOT edit below this line unless you know what you are doing. ##### --> | <!-- ##### DO NOT edit below this line unless you know what you are doing. ##### --> | ||
Revision as of 11:19, 12 September 2009
 Conference and seminar notes
|
<html><img src="/images/9/94/Report.png" border="0" /></html> Main project page <html><img src="/images/c/c3/Resultset_previous.png" border="0" /></html>Previous entry<html> </html>Next entry<html><img src="/images/5/5c/Resultset_next.png" border="0" /></html> |
First day of 6th Intl Neural Tube Defects conferenceI arrived super late the first morning thanks to an epic 34-hour journey during which I slept 6 in a bed. First talk where I took notes: 6th Intl NTD Conference: first day = September 12, 2009 • Claudia Kappen – diabetic embryopathy Recent publication – effect on Wnt pathway genes in the induced diabetes model (injection of mice with streptozotocin, down insulin, blood sugar up, mate the dams at day 15. Get 10-15% NTDs at E10.5 and beyond. Genes mostly downreg in the embryo proper, also looked at and mostly reported the results in the placenta. Prevention of diabetic NTDs with folic acid (somewhat controversial). Breeder diet before mating dams >= 6 weeks. Timing of gene expression changes in induced diabetes model is different depending on Chow or Breeder diets (differ by 10% protein/fat, less folic acid in latter, same carbs). On Breeder-fed FPB mice, get more NTDs in diabetes-exposed (22% vs 6.6% on Chow diet) embryos. But revealed at the later stages in development, not seen by looking only at E10.5, also look at E12.5, E15.5, E18.5 (increasing incidence). Macrosomia in diabetic humans – different in mouse. How much related to the maternal obesity to start? Rarely observed in rodent models, but the diabetes is very severe. Questions: Genetic reasons for dietary effects of Chow vs Breeder in other strains of mice 4 misregulated imprinted genes (3 down, 1 up in diabetes) and 3 regulators of imprinting are misregulated. Since 10.5 is > neural tube closure (can ascertain if NTD then) then how relevant? Maternal diabetes changes in the affected embryos? Variance is as great as in the non-affected exposed embryos. • Mary Loeken - ChIP on Pax3 promoter Diabetes much reduces Pax3 – at E10.5 the exencephaly looks like the Splotch phenotype. Less expn at E8.5. Not all the embryos develop malformations. Stochastic NTD occurrence re: exposure to hyperglycemia (glucose necessary and sufficient to inhibit Pax3 by inducing oxidative stress) during a critical window. Drug induces oxidative stress: antimycin A; antioxidants reduce hyperglycemia. Using ES cells to plate and study molecular regulation. (Experiments described in D3 cells derived from 129 Sv strain.) Transfer ES cells to Petri dish and RA stimulation to form embryoid bodies. Select for nestin + precursors on ITSF + medium, get neuronal precursor-looking cells on the newly adherent plastic. Pax3 induced on differentiation, but abrogated with antomycin A, some other gene expression is maintained including nestin. Rather than high glucose: the D3 cells are cultured in a high glucose DMEM anyhow and have lost glucose response. Differentiating cells with or without ox stress. Perform ChIP. PCR Pax3 5’ elements. “Pan-H3” antibody, H3K27me3 (decreased expn), H3K4me3, H3K9ac (increased expn). 1.6kb upstream – strategy = primers amplifying overlapping 200bp amplicons, overlap by 100bp. 1.6kb directs Pax3 expn in NT aside from a part of the head and NCC. Doesn’t control expn in somites. -180 and -400 seems to be concentration of sites. What other chromatin modifications provide access? Get changes at best 1.5-2x, but error bars are very reproducible (relative IPm though to what?). Change at -1000 to -1200 on differentiation. H3K27me3 – no real changes but on a log scale and overall much noisier. H3K4me4, get changes over 3 conditions (before diffn, after selection/readhesion, and after but with antimycin A). Eg -200 to -400 v.low to start (0.01, then 1 for the after, and back down for antimycin treatment). Histone me inhibitor on lysine = chaetocin, HDAC inhibitor TSA. No effects in undiff condition, but addition instead of the antimycin treatment will inhibit Pax3 expression (relative expn, using qPCR). Questions: Immunohisto Pax3 – almost all cells are expressing, usually. Folic acid deficiency by up homocysteine, ionizing radiation, other causes of oxidative stress. Specific kinds of free radicals are responsible - increased superoxide production eg. What happens in Pax3 htz? Could not induce C57Bl/6 background maternal diabetes effect NTD even in the Pax3 – and this is a dominant effect. But Splotch on another background, maybe – difference due to glucose transporters? Would like to do ChIP-seq perhaps. Role for inositol supplementation cf diabetes? Alleviation reported in the rat in vitro… Fatty acids work as antioxidants. Or substrate for something playing a signaling role?
Glucose metabolism genes associated with spina bifida risk or AD/HD in SB patients. 22% white US women obese, 24% men; Canada 25%; black and Hispanic populations are around 30%. Leptin and glucose transporter (glut1/2/3) genes SNPs associated with increased BMI. Cf. Davidson 2008 – SNPs and SB. How well do lymphocytes from patients take up glucose? Isolate from patients and mother, test under 3 conditions – normal, hi glucose, sucrose conditions, do they take up, according to GLUT1 haplotype? (or HK1, or LEPR) genotypes: the significant results are from the LEPR genotypes. Subdivide populations into these three subpopulations. Some SNPs have sig differences, using TDT instead. 140 SNPs analyzed using RC-TDT: BRCA1, GLUT1,/3/4/8, HK1, LEPR, INSR, LEP, SOD1/2, TP53. Plot –log p and get significant results for many SNPs in GLUT1 in particular rs3339682 reproduce previous findings from other groups as associated with SB in patients. Linkage disequilibrium of 10 sign GLUT1 SNPs comparing Hispanic vs Caucasian populations, but though seem different he thinks they are not actually… did not quite catch this.
Folic acid consumption including diet (enriched cereal grain products w/o ready to eat cereals), ECGP+cereals, ECGP+cereals+supplements. Used PC-SIDE software for intake distributions estimation, also accounted for race, ethnicity, sex, BMI, day of week as weekend diet can differ from weekdays. Calculate nutrient concentrations through a whole series of stat methods I am not qualified to assess but sound good. Complex sampling design. Usual total folic acid daily intake in 8,258 US adults. Median = 288 ug per day (160-462) and 2.7% at 95CI consumed >1mg. ECGP only 42% of adults, median = 138; ECGP+RTE cereals 274 ug, none exceeded tolerable upper limit. ECGP+supplements, 479 ug, 5.5% exceeded UL, 635, 9.4% exceeded UL. Consistent across all race, ethnicity, etc. Adults aged 65 and over 12.8% exceeded the upper limit and had ECGP, supplements and breakfast cereals. 11% adults up to 200 ug/day from supplements. Less than 1% exceeded UL. >400 ug/day, 48% of these exceeded the UL. 200-400 ug/day, again less than 1% exceeded UL % US adults with high serum folate and low B12 concentrations inverse relationship where up to 30% of ECGP+RTE cereals+supplements had >20ng/mL but decline with other sources of folic acid (from vitamin B12?). I didn’t get it – went too fast. But it keeps homocysteine down. Supplements for folic acid also have B12 reducing risk for B12 deficiency. Despite contributions from diet, RTE cereals and supplements <400 ug/day, 94% US adults won’t go over the recommended tolerable upper limit of 1 mg/day.
Women of childbearing age but non pregnant in the cohort previously described. USDA and public health service recommendations – 400 ug/day if trying to get pregnant. Some recommendations up to 800 ug/day (USPSTF where TF is task force). Women with obesity or diabetes don’t particularly increase their folic acid intake and don’t make particular population-visible efforts to take supplements – conclusion, they should, because no women of childbearing age sub-populations are really able to get to the recommendations on diet alone. Questions: Tough with non-supplemented diet to get folate levels. Before supplements between 100 and 10000 years ago, was there a selective impact on the species? Was there another dietary source or were all those particular babies lost? Answer (of course): I don’t know! RCT’s were only done on synthetic folic acid. Other members of the audience chipped in: But although we think we are sophisticated in our eating habits, earlier populations may have actually eaten more appropriate food to prevent certain vitamin deficiencies, when the food itself was available. “Paleolithic diet” currently in fashion – yet would have it been up to 400 ug/day?
| |
