Comparison of lidocaine and lidocaine-xylazine for distal paravertebral anesthesia in dairy cattle.

OBJECTIVE: To determine the time of onset and duration of action of distal paravertebral blocks (DPB) in dairy cattle using lidocaine and lidocaine plus xylazine (LX). ANIMALS: 10 healthy adult Holstein cows. METHODS: Unilateral DPB were performed in 6 cows at L1, L2, and L4. They received 2 treatments (lidocaine and LX) in a blinded random crossover design. Due to treatment failure, 4 additional cows were enrolled. The lidocaine treatment received 1,800 mg (90 mL) of lidocaine, and treatment LX received 1,784 mg (89.2 mL) of lidocaine and 16 mg (0.8 mL) of xylazine. Anesthesia was assessed by response (rapid movements of the tail, directed movements of the feet, or turning of the head towards the site of the needle pricks) to 6 approximately 1-cm deep needle pricks to the paralumbar fossa with a 22-gauge hypodermic needle. The time of onset, duration of action, maximum sedation score, and average heart rate (HR) were compared between treatments. RESULTS: Duration of anesthesia was significantly prolonged after DPB in cows treated with LX (251.6 ± 96.94 minutes) compared to lidocaine (105.8 ± 35.9 minutes; P = .01). Treatment with LX was associated with significantly lower average heart rate (56 ± 3 beats/min) compared to cows treated with lidocaine (59 ± 3 beats/min; P = .045). The LX treatment was associated with mild sedation but was not significant (P = .063). CLINICAL RELEVANCE: The addition of xylazine to a lidocaine DPB provides a longer duration of anesthesia, is inexpensive and practical, and can be implemented with ease.

Does DNA methylation in the fetal brain leave an epigenetic memory in the blood?

Epigenetic memory is an emerging concept that refers to the process in which epigenetic changes occurring early-in life can lead to long-term programs of gene regulation in time and space. By leveraging neural network regression modeling of DNA methylation data in pigs, we show that specific methylations in the adult blood can reliably predict methylation changes that occurred in the fetal brain. Genes associated with these methylations represented known markers of specific cell types of blood including bone marrow hematopoietic progenitor cells, and ependymal and oligodendrocyte cells of brain. This suggested that methylation changes that occurred in the developing brain were maintained as an epigenetic memory in the blood through the adult life.

Epigenetic regulation of fetal brain development in pig.

How fetal brain development is regulated at the molecular level is not well understood. Due to ethical challenges associated with research on the human fetus, large animals particularly pigs are increasingly used to study development and disorders of fetal brain. The pig fetal brain grows rapidly during the last âˆ¼ 50 days before birth which is around day 60 (d60) of pig gestation. But what regulates the onset of accelerated growth of the brain is unknown. The current study tests the hypothesis that epigenetic alteration around d60 is involved in the onset of rapid growth of fetal brain of pig. To test this hypothesis, DNA methylation changes of fetal brain was assessed in a genome-wide manner by Enzymatic Methyl-seq (EM-seq) during two gestational periods (GP): d45 vs. d60 (GP1) and d60 vs. d90 (GP2). The cytosine-guanine (CpG) methylation data was analyzed in an integrative manner with the RNA-seq data generated from the same brain samples from our earlier study. A neural network based modeling approach was implemented to learn changes in methylation patterns of the differentially expressed genes, and then predict methylations of the brain in a genome-wide manner during rapid growth. This approach identified specific methylations that changed in a mutually informative manner during rapid growth of the fetal brain. These methylations were significantly overrepresented in specific genic as well as intergenic features including CpG islands, introns, and untranslated regions. In addition, sex-bias methylations of known single nucleotide polymorphic sites were also identified in the fetal brain ide during rapid growth.

Fetal origin of sex-bias brain aging.

DNA methylation plays crucial roles during fetal development as well as aging. Whether the aging of the brain is programmed at the fetal stage remains untested. To test this hypothesis, mouse epigenetic clock (epiclock) was profiled in fetal (gestation day 15), postnatal (day 5), and aging (week 70) brain of male and female C57BL/6J inbred mice. Data analysis showed that on week 70, the female brain was epigenetically younger than the male brain. Predictive modeling by neural network identified specific methylations in the brain at the developing stages that were predictive of epigenetic state of the brain during aging. Transcriptomic analysis showed coordinated changes in the expression of epiclock genes in the fetal brain relative to the placenta. Whole-genome bisulfite sequencing identified sites that were methylated both in the placenta and fetal brain in a sex-specific manner. Epiclock genes and genes associated with specific signaling pathways, primarily the gonadotropin-releasing hormone receptor (GnRHR) pathway, were associated with the sex-bias methylations in the placenta as well as the fetal brain. Transcriptional crosstalk among the epiclock and GnRHR pathway genes was evident in the placenta that was maintained in the brain during development as well as aging. Collectively, these findings suggest that sex differences in the aging of the brain are of fetal origin and epigenetically linked to the placenta.

Fetal Brain Elicits Sexually Conflicting Transcriptional Response to the Ablation of Uterine Forkhead Box A2 (Foxa2) in Mice.

In this study, we investigated the effects of ablation of uterine Forkhead Box A2 (Foxa2) on gene expression of fetal brain relative to placenta. Using a conditional knockout mouse model for uterine Foxa2, here we show that the lack of uterine Foxa2 elicits a sexually-conflicting transcriptional response in the fetal brain relative to placenta. The ablation of Foxa2 in the uterus altered expression of genes related to growth, nutrient sensing, aging, longevity and angiogenesis among others. In the wildtype mice, these genes were expressed higher in the fetal brain and placenta of males compared to females. However, in mice lacking uterine Foxa2, the same genes showed the opposite pattern i.e., higher expression in the fetal brain and placenta of females compared to males. Based on the known marker genes of mice placenta and fetal brain cells, we further predicted that the genes exhibiting the sexually conflicting expression were associated with vascular endothelial cells. Overall, our study suggests that uterine Foxa2 plays a role in the regulation of the brain-placental axis by influencing the fetoplacental vascular changes during pregnancy.

Sexually Dimorphic Transcriptomic Changes of Developing Fetal Brain Reveal Signaling Pathways and Marker Genes of Brain Cells in Domestic Pigs.

In this study, transcriptomic changes of the developing brain of pig fetuses of both sexes were investigated on gestation days (GD) 45, 60 and 90. Pig fetal brain grows rapidly around GD60. Consequently, gene expression of the fetal brain was distinctly different on GD90 compared to that of GD45 and GD60. In addition, varying numbers of differentially expressed genes (DEGs) were identified in the male brain compared to the female brain during development. The sex of adjacent fetuses also influenced gene expression of the fetal brain. Extensive changes in gene expression at the exon-level were observed during brain development. Pathway enrichment analysis showed that the ionotropic glutamate receptor pathway and p53 pathway were enriched in the female brain, whereas specific receptor-mediated signaling pathways were enriched in the male brain. Marker genes of neurons and astrocytes were significantly differentially expressed between male and female brains during development. Furthermore, comparative analysis of gene expression patterns between fetal brain and placenta suggested that genes related to ion transportation may play a key role in the regulation of the brain-placental axis in pig. Collectively, the study suggests potential application of pig models to better understand influence of fetal sex on brain development.

Relevance of microRNAs to the regulation of the brain-placental axis in mice.

INTRODUCTION: The development of fetal brain is intricately dependent upon placental functions. Recently, we showed that the placenta and fetal brain express genes in a coordinated manner in mice. But, how the brain-placental axis is regulated at the molecular level remains poorly understood. The microRNAs (miRNAs) play diverse roles in pregnancy including regulation of placenta function as well as brain development. Thus, we hypothesized that specific miRNAs are expressed in the placenta and fetal brain to coordinate gene regulation in the brain-placental axis. METHODS: To test this hypothesis, we performed deep sequencing of small RNAs in mouse placenta and fetal brain of both sexes. RESULTS: The findings study show that miRNAs are potent regulators of gene expression in the placenta and fetal brain. Our data provides evidence that fetal sex influences the regulation of miRNAs between the placenta and fetal brain. Functional annotation of known target genes of the differentially expressed miRNAs show that they are significantly enriched with specific signaling and transporter pathways. DISCUSSION: Together, the results of this study suggest that placental miRNAs are potent regulators of fetal brain development in mice.