Identification of a Preliminary Plasma Metabolome-based Biomarker for Circadian Phase in Humans.

Measuring individual circadian phase is important to diagnose and treat circadian rhythm sleep-wake disorders and circadian misalignment, inform chronotherapy, and advance circadian science. Initial findings using blood transcriptomics to predict the circadian phase marker dim-light melatonin onset (DLMO) show promise. Alternatively, there are limited attempts using metabolomics to predict DLMO and no known omics-based biomarkers predict dim-light melatonin offset (DLMOff). We analyzed the human plasma metabolome during adequate and insufficient sleep to predict DLMO and DLMOff using one blood sample. Sixteen (8 male/8 female) healthy participants aged 22.4 ± 4.8 years (mean ± SD) completed an in-laboratory study with 3 baseline days (9 h sleep opportunity/night), followed by a randomized cross-over protocol with 9-h adequate sleep and 5-h insufficient sleep conditions, each lasting 5 days. Blood was collected hourly during the final 24 h of each condition to independently determine DLMO and DLMOff. Blood samples collected every 4 h were analyzed by untargeted metabolomics and were randomly split into training (68%) and test (32%) sets for biomarker analyses. DLMO and DLMOff biomarker models were developed using partial least squares regression in the training set followed by performance assessments using the test set. At baseline, the DLMOff model showed the highest performance (0.91 R2 and 1.1 ± 1.1 h median absolute error ± interquartile range [MdAE ± IQR]), with significantly (p < 0.01) lower prediction error versus the DLMO model. When all conditions (baseline, 9 h, and 5 h) were included in performance analyses, the DLMO (0.60 R2; 2.2 ± 2.8 h MdAE; 44% of the samples with an error under 2 h) and DLMOff (0.62 R2; 1.8 ± 2.6 h MdAE; 51% of the samples with an error under 2 h) models were not statistically different. These findings show promise for metabolomics-based biomarkers of circadian phase and highlight the need to test biomarkers that predict multiple circadian phase markers under different physiological conditions.

EphrinB2 repression through ZEB2 mediates tumour invasion and anti-angiogenic resistance.

Diffuse invasion of the surrounding brain parenchyma is a major obstacle in the treatment of gliomas with various therapeutics, including anti-angiogenic agents. Here we identify the epi-/genetic and microenvironmental downregulation of ephrinB2 as a crucial step that promotes tumour invasion by abrogation of repulsive signals. We demonstrate that ephrinB2 is downregulated in human gliomas as a consequence of promoter hypermethylation and gene deletion. Consistently, genetic deletion of ephrinB2 in a murine high-grade glioma model increases invasion. Importantly, ephrinB2 gene silencing is complemented by a hypoxia-induced transcriptional repression. Mechanistically, hypoxia-inducible factor (HIF)-1α induces the EMT repressor ZEB2, which directly downregulates ephrinB2 through promoter binding to enhance tumour invasiveness. This mechanism is activated following anti-angiogenic treatment of gliomas and is efficiently blocked by disrupting ZEB2 activity. Taken together, our results identify ZEB2 as an attractive therapeutic target to inhibit tumour invasion and counteract tumour resistance mechanisms induced by anti-angiogenic treatment strategies.

Effects of calcium salts of soybean oil on factors that influence pregnancy establishment in Bos indicus beef cows.

The objective of this experiment was to compare fatty acid (FA) concentrations in plasma and reproductive tissues as well as hormones and expression of genes associated with pregnancy establishment in beef cows supplemented or not with Ca salts of soybean oil (CSSO) beginning after timed AI. Ninety nonlactating multiparous Nelore (Bos indicus) cows were timed inseminated on d 0 of the experiment and divided into 18 groups of 5 cows/group. Groups were randomly assigned to receive (as-fed basis) 100 g of a protein-mineral mix plus 100 g of ground corn per cow daily in addition to 1) 100 g/cow daily of CSSO (n = 9) or 2) 100 g/cow daily of kaolin (CON; rumen-inert indigestible substance; n = 9). All groups were maintained in a single Brachiaria brizanta pasture (24 ha) with ad libitum access to forage and water. However, groups were segregated daily and offered treatments individually at the working facility during the experimental period (d 0 to 18). Blood samples were collected and transrectal ultrasonography was performed to verify ovulation and estimate corpus luteum (CL) volume immediately before AI (d 0) and on d 7 and 18 of the experiment. On d 19, 36 cows (18 cows/treatment; 2 cows/group) diagnosed without the presence of a CL on d 0 but with a CL greater than 0.38 cm(3) in volume on d 7 and 18 were slaughtered for collection of conceptus, uterine luminal flushing, and tissue samples from the CL and endometrium. Cows receiving CSSO had greater concentrations of linoleic and other ω-6 FA in plasma (P < 0.01), endometrium (P ≤ 0.05), CL (P ≤ 0.05), and conceptus (P ≤ 0.08) compared to CON. On d 7 of the experiment, CSSO-supplemented cows had greater plasma progesterone concentrations (P < 0.01) and CL volume (P = 0.02) compared to CON, whereas no treatment effects were detected (P ≥ 0.15) for these parameters on d 18 (treatment × day interaction; P < 0.01). Cows receiving CSSO tended (P = 0.09) to have greater concentrations of interferon-tau in the uterine flushing media compared with CON. However, no treatment effects were detected for mRNA expression genes associated with pregnancy establishment in endometrial, CL, and conceptus samples (P ≥ 0.12). In summary, supplementing beef cows with 100 g of CSSO beginning after AI favored incorporation of ω-6 FA into their circulation, reproductive tissues, and conceptus, without impacting expression of genes associated with pregnancy establishment on d 19 of gestation.

Young Investigator's Prizewinner 2001. Direct visualization of the influence of normothermic as opposed to hypothermic cardiopulmonary bypass on the systemic microcirculation in neonatal piglets.

The direct visualization of systemic microcirculation using intravitalmicroscopy permits the classification of proinflammatory and ischemic microvascular alterations during normothermic and hypothermic cardiopulmonary bypass in neonates. We used seven newborn piglets, on average aged 9 days, and weighing 3200g, as a control group. In addition, we studied nine piglets subjected to 60 minutes of constant nonpulsatile flow using hypothermic extracorporeal circulation at 28 degrees C, and five piglets using normothermic conditions at 37 degrees C. The microvascular network of the greater omentum and the subcutaneous tissue was directly visualized using intravitalmicroscopy. We analysed interactions between leukocytes and endothelial cells, microvascular morphology, and microrheological conditions, focussing on signs of ischemic and proinflammatory alterations. During normothermic cardiopulmonary bypass, the numbers of activated leukocytes were elevated compared to hypothermic cardiopulmonary bypass (p > 0.05). Arteriolar diameter decreased during hypothermia. Capillaries were markedly dilated during normothermia. Patterns of microvascular perfusion, for both types of cardiopulmonary bypass, showed signs of ischemic damage, revealed by a reduced functional capillary density. Perfusion dependent levels of lactate were higher during normothermic cardiopulmonary bypass (p > 0.05). This new experimental approach revealed that non-pulsatile cardiopulmonary bypass, independent of temperature, induces a proinflammatory and ischemic response compared to an unaltered control group. The markedly elevated numbers of activated adherent leukocytes, the reduced capillary density, and the high lactate levels in those undergoing bypass in normothermic conditions indicate a more pronounced inflammatory stimulus and tissue hypoperfusion compared to the possible protective effect of hypothermia for children undergoing cardiopulmonary bypass.

Supportive relationships in later life.

We adopted a multidimensional approach to the study of the social support convoys of older adults. We distinguished between age and gender differences in four specific dimensions of the social support convoy: (a) existence versus functioning of relationships in the convoy, (b) kinds of relationships (i.e., those with children, siblings, and friends), (c) types of social support (i.e., emotional support, respect, and health support), and (d) receipt versus provision of support. Using a national survey of 718 adults, multivariate and univariate analyses of variance were performed to determine age and gender differences in these four dimensions of social support. The multidimensional approach was useful in pinpointing those aspects of the social support convoy affected by aging. We anticipated that the social support convoy would be devastated by aging. Instead, we found that older people received less support (i.e., emotional and health support) in the absence of sibling relationships. Otherwise, the effects of aging had more to do with what the older person contributed to the convoy than with what he or she received. Women had better social support resources than men, particularly within their friendships. We found no evidence, however, that women's social support advantage counterbalanced the effects of aging on the convoy.

Conjugal social support: patterns in later life.

This investigation of conjugal social support was based on 412 married respondents from a national sample of adults 50 years of age or older. A review of the literature yielded hypotheses concerning the exchange of three forms of support: emotional support, respect, and health-related support. Results showed that older respondents were least likely to provide each form of social support. These findings were reviewed in light of evidence for increased need for support in later life. The perceptual bases of social support were discussed in conjunction with the finding that women perceive less social support within marriage than men.