Aging effects on DNA methylation modules in human brain and blood tissue

Background

Several recent studies reported aging effects on DNA methylation levels of individual CpG dinucleotides. But it is not yet known whether aging-related consensus modules, in the form of clusters of correlated CpG markers, can be found that are present in multiple human tissues. Such a module could facilitate the understanding of aging effects on multiple tissues.

Results

We therefore employed weighted correlation network analysis of 2,442 Illumina DNA methylation arrays from brain and blood tissues, which enabled the identification of an age-related co-methylation module. Module preservation analysis confirmed that this module can also be found in diverse independent data sets. Biological evaluation showed that module membership is associated with Polycomb group target occupancy counts, CpG island status and autosomal chromosome location. Functional enrichment analysis revealed that the aging-related consensus module comprises genes that are involved in nervous system development, neuron differentiation and neurogenesis, and that it contains promoter CpGs of genes known to be down-regulated in early Alzheimer's disease. A comparison with a standard, non-module based meta-analysis revealed that selecting CpGs based on module membership leads to significantly increased gene ontology enrichment, thus demonstrating that studying aging effects via consensus network analysis enhances the biological insights gained.

Conclusions

Overall, our analysis revealed a robustly defined age-related co-methylation module that is present in multiple human tissues, including blood and brain. We conclude that blood is a promising surrogate for brain tissue when studying the effects of age on DNA methylation profiles.     

A benefit-finding intervention for family caregivers of persons with Alzheimer disease: study protocol of a randomized controlled trial

Background

Patients with ST-elevation myocardial infarction (STEMI) not treated with primary or rescue percutaneous coronary intervention (PCI) are at risk for recurrent ischemia, especially when viability in the infarct-area is present. Therefore, an invasive strategy with PCI of the infarct-related coronary artery in patients with viability would reduce the occurrence of a composite end point of death, reinfarction, or unstable angina (UA).

Methods

Patients admitted with an (sub)acute myocardial infarction, who were not treated by primary or rescue PCI, and who were stable during the first 48 hours after the acute event, were screened for the study. Eventually, we randomly assigned 216 patients with viability (demonstrated with low-dose dobutamine echocardiography) to an invasive or a conservative strategy. In the invasive strategy stenting of the infarct-related coronary artery was intended with abciximab as adjunct treatment. Seventy-five (75) patients without viability served as registry group. The primary endpoint was the composite of death from any cause, recurrent myocardial infarction (MI) and unstable angina at one year. As secondary endpoint the need for (repeat) revascularization procedures and anginal status were recorded.

Results

The primary combined endpoint of death, recurrent MI and unstable angina was 7.5% (8/106) in the invasive group and 17.3% (19/110) in the conservative group (Hazard ratio 0.42; 95% confidence interval [CI] 0.18-0.96; p = 0.032). During follow up revascularization-procedures were performed in 6.6% (7/106) in the invasive group and 31.8% (35/110) in the conservative group (Hazard ratio 0.18; 95% CI 0.13-0.43; p < 0.0001). A low rate of recurrent ischemia was found in the non-viable group (5.4%) in comparison to the viable-conservative group (14.5%). (Hazard-ratio 0.35; 95% CI 0.17-1.00; p = 0.051).

Conclusion

We demonstrated that after acute MI (treated with thrombolysis or without reperfusion therapy) patients with viability in the infarct-area benefit from a strategy of early in-hospital stenting of the infarct-related coronary artery. This treatment results in a long-term uneventful clinical course. The study confirmed the low risk of recurrent ischemia in patients without viability.

Trial registration

ClinicalTrials.gov: NCT00149591.     

Fertilization and early embryonic development in the blue fox (Alopex lagopus)

A total of 15 blue fox vixens aged 1–6 years were mated, 12 once on the first day of estrus and three a second time 48 hr after the first mating, and were killed 4 hr to 8 days following mating. Ova were collected from the oviducts, evaluated by stereomicroscopy, and studied by transmission (TEM; N = 49, 12 vixens) or scanning (SEM, N = 11, three vixens) electron microscopy. At 0–3 days after ovulation, the ova had not cleaved and were at different stages of meiotic maturation. In about one-half of these ova, representing all stages of meiotic maturation, a decondensing sperm head without nuclear envelope or a small pronucleus with partial nuclear envelope was observed. No clear relationship was found between maternal meiotic stage and the stage of paternal pronucleus formation. Sperm tails were never identified in the ooplasm. Cortical granules were released after sperm penetration at early stages of meiotic maturation. Thus the block against polyspermic penetration was activated during maturation of the oocyte. The first two-cell stage appeared 4 days after ovulation (3 days after mating), the first four-cell stage the following day (day 5), and the first eight-cell stage 6 days after ovulation (5 days after mating). In a single vixen mated late (7 days postovulation) two- to four-cell stages appeared the following day (day 8). This indicates that the time required for the first cleavage division decreases with increasing interval from ovulation to mating. The development of a functional nucleolus with fibrillar centers and fibrillar and granular components at the eight-cell stage indicates activation of embryonic RNA synthesis in fox embryos at the six- to eight-cell stage, suggesting that the embryonic genome is activated at this stage. © 1993 Wiley-Liss, Inc.     

NEUROCHEMICAL PARAMETERS IN THE HYPERRESPONSIVE PHASE AFTER A SINGLE DOSE OF NEUROLEPTICS TO MICE

Abstract— Four days after a single dose of teflutixol (5 mg/kg i.p.), at which time mice are superresponsive to dopamine agonists, e.g. apomorphine, the specific binding of [³H]haloperidol, [³H]cis (Z)-flupenthixol, [³H]apomorphine, [³H]dopamine, [³H]propylbenzilylcholine mustard and [³H]GABA to striatal membranes in vitro is equal to that of saline-treated mice. Specific binding of [³H]haloperidol is also unchanged 3 days following a single dose of fluphenazine (5mg/kg i.p.) and 2 days following haloperidol (5 mg/kg i.p.), but slightly decreased 3 days following cis(Z)-flupenthixol (5 mg/kg i.p.).
The possibility that remaining neuroleptic or active metabolites could obscure a slight increase in dopamine receptor binding was rejected, since remaining amounts of [³H]teflutixol in the final binding assay 4 days after intraperitoneal injection of [³H]teflutixol (5 mg/kg) were too small to influence the binding of [³H]haloperidol in vitro .
It is concluded that the pharmacological superresponsiveness and the decrease in dopamine synthesis and release seen after the initial receptor blockade following a single dose of neuroleptic drugs in mice are nor accompanied by changes in dopamine, muscarine or GABAergic receptor characteristics in corpus striatum. The possibility that changes occur in a small number of functional operative dopamine receptors cannot be excluded, however.     

Modeling human arthritic diseases in nonhuman primates

Models of rheumatoid arthritis (RA) in laboratory animals are important tools for research into pathogenic mechanisms and the development of effective, safe therapies. Rodent models (rats and mice) have provided important information about the pathogenic mechanisms. However, the evolutionary distance between rodents and humans hampers the translation of scientific principles into effective therapies. The impact of the genetic distance between the species is especially seen with treatments based on biological molecules, which are usually species-specific. The outbred nature and the closer anatomical, genetic, microbiological, physiological, and immunological similarity of nonhuman primates to humans may help to bridge the wide gap between inbred rodent strain models and the heterogeneous RA patient population. Here we review clinical, immunological and pathological aspects of the rhesus monkey model of collagen-induced arthritis, which has emerged as a reproducible model of human RA in nonhuman primates.     

Superovulatory response of dairy cattle (Bos taurus ) in a tropical environment

Dairy (Bos taurus) heifers and cows (n = 40) in a tropical environment were treated during mid-luteal phase using either SUPER-OV(R) or OVAGEN to induce superovulatory response after synchronization of the superovulatory estrus with a synthetic progestagen and cloprostenol (PG). Estrous cattle were inseminated twice using frozen-thawed semen, and embryos were recovered nonsurgically, on-farm, 7 d later. Between initiation of gonadotrophin treatment and recovery of embryos, 4 blood samples per animal were collected from 26 animals for determination of plasma progesterone (P4) concentration. Two (5%), 28 (70%) and 10 (22%) of the animals were observed in estrus 1.5, 2 and 2.5 to 3 d after PG, respectively. There was no difference (P = 0.7) in the number of palpable CL between animals treated with SUPER-OV (7.6 +/- 1.0; n = 18) and those treated with OVAGEN (7.9 +/- 1.1; n = 22). There was also no significant difference (P > 0.05) between Jersey vs Ayrshire breeds or heifers vs cows in the ovarian response as estimated by the number of palpable CL. However, a higher proportion of Ayrshire cattle and donors treated with OVAGEN yielded a higher total number and viable/transferable embryos than Jersey and SUPER-OV-treated cattle. There was a significant (P < 0.05) correlation between the number of CL and total number of embryos (r = 0.65); the number of transferable embryos was also significantly related to the total number of embryos per recovery (r = 0.85; P < 0.05). For 15 animals with normal P4 profiles, the mean (+/-SEM) plasma P4 concentration was 14.4 +/- 0.8, 0.5 +/- 0.2, 5.4 +/- 1.1 and 39.4 +/- 3.0 nmol L at initiation of gonadotrophin treatment, superovulatory estrus and Days 3 and 7, respectively. The mean (+/-SEM) interval between a PG injection given after embryo recovery and the induced estrus was 7.1 +/- 0.7 d (range 3 to 14 d) and the length of the superovulatory cycle was 24.1 +/- 3.2 d (range 12 to 35 d).     

Resumption of meiosis induced by meiosis-activating sterol has a different signal transduction pathway than spontaneous resumption of meiosis in denuded mouse oocytes cultured in vitro.

The sterol 4,4-dimethyl-5-cholesta-8,14,24-trien-3-ol (follicular fluid meiosis-activating sterol [FF-MAS]) isolated from human follicular fluid induces resumption of meiosis in mouse oocytes cultured in vitro. The purpose of this study was to examine the hypothesis that differential signal transduction mechanisms exist for FF-MAS-induced and spontaneous in vitro resumption of meiosis in mouse oocytes. Mouse oocytes were dissected from ovaries originating from mice primed with FSH 48 h before oocyte collection. Mechanically denuded germinal vesicle (GV) oocytes were in vitro matured in medium supplemented with hypoxanthine and FF-MAS or allowed to mature spontaneously; both groups were exposed to individual compounds known to inhibit specific targets in the cell. After 20-22 h of in vitro maturation, resumption of meiosis was assessed as the frequency of oocytes in GV breakdown (GVBD) stage. Pertussis toxin (2.5 microg/ml) did not influence resumption of meiosis in either group. Dibutyryl cyclic GMP (320 microM) inhibited FF-MAS-induced GVBD, but not spontaneous GVBD, whereas the subtype 5 phosphodiesterase-inhibitor zaprinast (50 microM) inhibited GVBD in both groups. Microinjection of the catalytic subunit of cAMP-dependent protein kinase into oocytes inhibited spontaneous GVBD, but not FF-MAS-induced GVBD. An inhibitor of cytoplasmic polyadenylation, cordycepin (80 microM), inhibited or retarded spontaneous GVBD to a further extent than it did FF-MAS-induced GVBD. Spontaneous GVBD was more sensitive to the histone H1 kinase-inhibitor olomoucine (250 microM) than was FF-MAS-induced GVBD. Addition of the mitogen-activated protein kinase (MAPK)-inhibitor PD 98059 (50 microM), phospholipase C-inhibitor U-73122 (10 microM), p21(ras)-inhibitor lovastatine (250 microM), and the src-like kinase inhibitor PP2 (20 microg/ml) inhibited FF-MAS-induced GVBD, but not spontaneous GVBD. Both MAPKs, extracellular regulated kinase (ERK) 1 and ERK2, were phosphorylated under FF-MAS-induced meiotic resumption, in contrast to spontaneous meiotic resumption, in which ERK1 and ERK2 phosphorylation occurred 2 h after GVBD. In the present study, we show that FF-MAS acts through an MAPK-dependent pathway, and we suggest that src-like kinase, p21(ras), and phosphoinositide signaling lie upstream of MAPK in the FF-MAS-activated signaling pathway. Clearly, striking pathway differences are present between spontaneous versus FF-MAS-induced meiotic resumption.     

Follicular Development and Ovulation in Sows: Effect of hCG and GnRH Treatment

Follicular growth, chronology of ovulation and embryo morphology were compared in sows ovulating spontaneously and sows, in which the ovulation was attempted induced by hCG or GnRH. Indwelling catheters were placed on day 1 (weaning = day 0) in the ear veins of 18 sows, which were then randomly divided into 3 groups: a control group (N = 6), a group (N = 6) given 750 iu hCG (Physex®) im 76h after weaning (hCG group) and a group (N = 6) given 500 µg GnRH (Fertagyl®) im 76h (N = 3) or 100h after weaning (N = 3) (GnRH group). Follicular diameter and time of ovulation were monitored by ultrasonography every 4h from day 3 until ovulation or development of cysts by means of a sector scanner fitted with a 5.0/7.5 MHz multiangle probe. Heat detection was performed every 8h from day 3 until ovulation. On day 13, the sows were slaughtered, the number of corpora luteae (CL) was counted, and embryos were flushed from the uteri. The control group showed clear heat symptoms, and on day 3, the follicles were typically 3–7 mm and grew up to 7–10 mm over 2 days, where they remained for approximately 24h until ovulation took place 41h ± 9h after first sign of standing heat. The hCG group exhibited no signs of heat, and the follicles only reached 5–8 mm in diameter at time of ovulation, which occurred 40h ± lh after hCG-injection. The GnRH group exhibited inconsistent signs of heat, and the follicles reached a maximum size of 7–12 mm in diameter where they remained for more than 24h. Only 2 sows in this group ovulated within 84–92h after the GnRH injection, and development of bursa cysts and cystic follicles was a common finding. The average number of CL was 18.2 ±5.7 per sow (N = 16, range: 3–27) with no significant difference between the groups. Total embryo recovery was 79 ± 13 % with no significant difference between groups. The embryo diversity calculated as standard deviation of the maximum diameter was higher in the hCG group as compared with the control group. It is concluded that (1) transrectal ultrasonography can be used in sows for accurate assessment of follicular growth and ovulation; (2) the use of hCG results in lack of heat symptoms and reduced follicle size at the time of ovulation when injected 76h after weaning; (3) administration of a single injection of GnRH, if given before the first signs of heat, results in inconsistent heat symptoms and no or late ovulations.