Age-dependent changes at the blood-brain barrier. A Comparative structural and functional study in young adult and middle aged rats

Abstract Decreased beta-amyloid clearance in Alzheimer’s disease and increased blood-brain barrier permeability in aged subjects have been reported in several articles. However, morphological and functional characterization of blood-brain barrier and its membrane transporter activity have not been described in physiological aging yet. The aim of our study was to explore the structural changes in the brain microvessels and possible functional alterations of P-glycoprotein at the blood-brain barrier with aging. Our approach included MR imaging for anatomical orientation in middle aged rats, electronmicroscopy and immunohistochemistry to analyse the alterations at cellular level, dual or triple-probe microdialysis and SPECT to test P-glycoprotein functionality in young and middle aged rats. Our results indicate that the thickness of basal lamina increases, the number of tight junctions decreases and the size of astrocyte endfeet extends with advanced age. On the basis of microdialysis and SPECT results the P-gp function is reduced in old rats. With our multiparametric approach a complex regulation can be suggested which includes elements leading to increased permeability of blood-brain barrier by enhanced paracellular and transcellular transport, and factors working against it. To verify the role of P-gp pumps in brain aging further studies are warranted

Alfalfa heat shock genes are differentially expressed during somatic embryogenesis

We have isolated two cDNA clones (Mshsp18-1; Mshsp18-2) from alfalfa (Medicago sativa L.) which encode for small heat shock proteins (HSPs) belonging to the hsp17 subfamily. The predicted amino acid sequences of the two alfalfa proteins are 92% identical and a similar degree of homology (90%) can be detected between Mshsp18-2 and the pea hsp17. In comparison to various members of small HSPs from soybean amino acid sequence similarities of 80-86% were identified. The alfalfa HSPs share a homologous stretch of amino acids in the carboxy terminal region with hsp22, 23, 26 from Drosophila. This region contains the GVLTV motif which is characteristic of several members of small HSPs. At room temperature alfalfa hsp18 mRNAs were not detectable in root and leaf tissues but northern analysis showed a low level of expression in microcallus suspension (MCS). The transcription of Mshsp18 genes is induced by elevated temperature, CdCl2 treatment and osmotic shock in cultured cells. In alfalfa somatic embryos derived from MCS a considerable amount of hsp18 mRNA can be detected during the early embryogenic stages under normal culture conditions. The differential expression of these genes during embryo development suggests a specific functional role for HSPs in plant cells at the time of the developmental switch in vitro

Transcriptomic Analysis of Porcine Endometrium during Implantation after In Vitro Stimulation by Adiponectin

Comprehensive understanding of the regulatory mechanism of the implantation process in pigs is crucial for reproductive success. The endometrium plays an important role in regulating the establishment and maintenance of gestation. The goal of the current study was to determine the effect of adiponectin on the global expression pattern of genes and relationships among differentially expressed genes (DE-genes) in the porcine endometrium during implantation using microarrays. Diverse transcriptome analyses including gene ontology (GO), biological pathway, networks, and DE-gene analyses were performed. Adiponectin altered the expression of 1286 genes with fold-change (FC) values greater than 1.2 (p < 0.05). The expression of 560 genes were upregulated and 726 downregulated in the endometrium treated with adiponectin. Thirteen genes were selected for real-time PCR validation of differential expression based on a known role in metabolism, steroid and prostaglandin synthesis, interleukin and growth factor action, and embryo implantation. Functional analysis of the relationship between DE-genes indicated that adiponectin interacts with genes that are involved in the processes of cell proliferation, programmed cell death, steroid and prostaglandin synthesis/metabolism, cytokine production, and cell adhesion that are critical for reproductive success. The presented results suggest that adiponectin signalling may play a key role in the implantation of pig

Expression of Chemerin and Its Receptors in the Porcine Hypothalamus and Plasma Chemerin Levels during the Oestrous Cycle and Early Pregnancy

Chemerin (CHEM) may act as an important link integrating energy homeostasis and reproductive functions of females, and its actions are mediated by three receptors: chemokine-like receptor 1 (CMKLR1), G protein-coupled receptor 1 (GPR1), and C-C motif chemokine receptor-like 2 (CCRL2). The aim of the current study was to compare the expression of CHEM and its receptor (CHEM system) mRNAs (quantitative real-time PCR) and proteins (Western blotting and fluorescent immunohistochemistry) in the selected areas of the porcine hypothalamus responsible for gonadotropin-releasing hormone production and secretion: the mediobasal hypothalamus, preoptic area and stalk median eminence during the oestrous cycle and early pregnancy. Moreover, plasma CHEM concentrations were determined using ELISA. The expression of CHEM system has been demonstrated in the porcine hypothalamus throughout the luteal phase and follicular phase of the oestrous cycle, and during early pregnancy from days 10 to 28. Plasma CHEM levels and concentrations of transcripts and proteins of CHEM system components in the hypothalamus fluctuated throughout pregnancy and the oestrous cycle. Our study was the first experiment to demonstrate the presence of CHEM system mRNAs and proteins in the porcine hypothalamus and the correlations between the expression levels and physiological hormonal milieu related to the oestrous cycle and early pregnancy