The expression of CD36 in vessels with blood-brain barrier impairment in a stroke-prone hypertensive model.

AIMS: The class B scavenger receptor CD36, the receptor for oxidized low-density lipoprotein, mediates free radical production and brain injury in cerebral ischaemia. Free radical production is known to be involved in the remodelling of the cerebral vasculature of stroke-prone spontaneously hypertensive rats (SHRSP). Accordingly, we examined whether the expression of CD36 is increased in the vasculature with blood-brain barrier (BBB) impairment and collagen deposition of SHRSP. METHODS: The gene and protein expression of CD36 was examined in the vessels of the hippocampus of SHRSP with BBB impairment and those of Wistar Kyoto rats without the impairment, by real-time RT-PCR, Western blotting and immunohistochemical techniques. RESULTS: The gene and protein expression of CD36 was increased in the hippocampus of SHRSP compared with that of Wistar Kyoto rats. Confocal microscopic examination revealed CD36 immunoreactivity in perivascular microglial cells immunopositive for ED1. Immunoelectron microscopic examination revealed that the immunosignals for CD36 were located mainly in the cytoplasm of perivascular cells in vessels showing increased vascular permeability and a few in the cytoplasmic membranes of endothelial cells. CONCLUSIONS: These findings indicate that the expression of CD36 was increased in vessels with BBB impairment in the hippocampus of SHRSP and was mainly seen in the cytoplasm of perivascular microglial cells, suggesting a role of CD36 in cerebrovascular injury.

The expression of P-glycoprotein is increased in vessels with blood-brain barrier impairment in a stroke-prone hypertensive model.

AIMS: We previously reported that the blood-brain barrier (BBB) function was impaired in vessels in the hippocampus in 3-month-old stroke-prone spontaneously hypertensive rats (SHRSP). In this study, we examined gene and protein expressions of P-glycoprotein, a representative efflux transporter of cerebral vessels, in the BBB-damaged hippocampal vessels of SHRSP and in the vessels of Wistar Kyoto (WKY) rats as controls, to clarify roles of the efflux transporter in the BBB-damaged vessels. METHODS: The expression of P-glycoprotein in hippocampal and cortical samples was examined by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunoelectron microscopic techniques. RESULTS: Real-time RT-PCR and Western blotting analyses revealed that the gene and protein expressions of P-glycoprotein were increased in the hippocampal samples of 3-month-old SHRSP compared with hippocampal samples of 3-month-old WKY rats or with cortical samples of SHRSP. The gene expression of P-glycoprotein was also increased in the hippocampal samples of 4-week-old SHRSP. Immunoelectron microscopic examination revealed that immunosignals of P-glycoprotein were seen in the luminal and ab-luminal cytoplasmic membranes of endothelial cells and the basal lamina, that the labelling density of P-glycoprotein in the vessel wall was higher in the hippocampus of 3-month-old SHRSP than in other groups and that the immunosignals of P-glycoprotein were occasionally co-located with those of albumin. CONCLUSIONS: These findings indicate that the expression of P-glycoprotein is increased in BBB-damaged hippocampal vessels in hypertensive SHRSP compared with those in WKY rats.

Ultrastructural and permeability features of microvessels in the hippocampus, cerebellum and pons of senescence-accelerated mice (SAM).

We previously reported that the accumulation of blood-borne radiolabelled serum albumin in brain parenchyma increased with aging, especially in senescence-accelerated mice (SAMP8), which showed age-related deficits in learning and memory. In this study, in order to examine morphological events related to the age-related increase of the brain accumulation of serum albumin, the transvascular passage of blood-borne horseradish peroxidase (HRP) and ultrastructural features of microvessels were examined in the hippocampus, cerebellum and pons of SAMP8 and SAMR1 (control) mice. Ultrastructural examination of the hippocampus showed that the staining for HRP was occasionally spreading throughout the parajunctional cytoplasm of the endothelial cell of aged SAMP8 mice, but not in young SAMP8 mice nor in SAMR1 mice. The number of vessels showing the staining reaction for HRP in the parajunctional cytoplasm of the endothelial cells in aged SAMP8 mice increased significantly compared with that in the others. Electron microscopic morphometry showed that there were no significant differences among the number of HRP-positive vesicles per unit area of the endothelial cell cytoplasm in young and old mice of both strains. The staining reaction for HRP was not seen in the basal lamina of microvessels and the perivascular neuropil in all mice examined. Perivascular lipofuscin-like granules and collagen deposits, swelling of astroglial perivascular endfeet and perivascular cells containing foamy, lipid-like droplets were frequently found in several brain regions of aged SAMP8 mice. The perivascular cells with a few lipid-like droplets and more electron-homogeneous lysosomes were occasionally seen in SAMR1 and young SAMP8, while the other findings were scarcely observed in SAMR1 and young SAMP8 mice. These findings suggest that the blood-brain barrier to HRP was preserved in microvessels in three brain regions of SAM mice but the blood microvessels showed some age-related ultrastructural alterations in SAMP8 brains. Uncontrolled passage of HRP through the parajunctional cytoplasm of the endothelial cells may partly contribute to the age-related increase of accumulation of serum albumin in SAMP8 brains.

Change of adrenomedullin concentrations in plasma and amniotic fluid, and human placental adrenomedullin expression with advancing gestation.

In order to characterize the expression of adrenomedullin during pregnancy, we measured the mature and total concentrations in maternal plasma and amniotic fluid, and examined its expression in fetoplacental tissues. Plasma samples were obtained from 13 normal normotensive non-pregnant women and 14 normal normotensive post partum women. Maternal plasma and amniotic fluid samples were obtained from 37 normal pregnant women (10 in the first trimester, 13 in the second trimester and 14 in the third trimester). Fetoplacental tissues were obtained from first and third-trimester pregnancies. Mature and total adrenomedullin concentrations in plasma and amniotic fluid were determined by using specific radioimmunoassay. The distribution and expression of adrenomedullin were determined using immunohistochemistry, reverse-transcriptase polymerase chain reaction, and in situ hybridization. Plasma total adrenomedullin concentrations were increasing with advancing gestation. The mature/total adrenomedullin ratio in the second trimester was the highest during pregnancy. Mature and total adrenomedullin concentrations in the amniotic fluid were significantly higher than those in the maternal plasma throughout gestation (P< 0.05). Mature adrenomedullin concentrations and the mature/total adrenomedullin ratio in the amniotic fluid increased with advancing gestation. There was a significant linear correlation between amniotic fluid and maternal plasma mature/total adrenomedullin ratio in the first or second trimester of pregnancy. Adrenomedullin mRNA was identified in the amniotic membrane and chorionic villi, and within the endothelial layers of villous blood vessels. These results suggest that the mature/total adrenomedullin ratio is modified in maternal plasma and amniotic fluid with advancing gestation.

Immunohistochemical study of transferrin receptor expression in the placenta of pre-eclamptic pregnancy.

Transport of iron from the mother to the fetus is essential for the normal development of the fetus and abnormalities in the transferrin receptor (TFR) on the placental trophoblasts might have some crucial effects on the fetal iron metabolism. The present study was undertaken to determine whether there are any changes in the expression of the transferrin receptor in the placenta from pre-eclamptic mothers. An immunohistochemical study using antibodies specific for C-terminus and N-terminus regions of the TFR revealed that TFR expression by syncytiotrophoblasts around chorionic villi is markedly reduced in placentae from pre-eclamptic pregnancies compared to those from normal pregnancies and pregnancies at early gestational age that terminated by abortion. The same result, although to a lesser extent, was obtained even in trophoblasts which were located around atrophic villi with fibrotic changes in the interstitium, or which invaded into the deciduas. The expression of human chorionic gonadotropin (HCG) on those cells was observed to the same extent in the normal and pre-eclamptic pregnancy groups. The concentration of TFR in the peripheral blood also decreased in pre-eclampsia. These results suggest that TFR synthesis in the pre-eclampsia, especially in the placental trophoblasts, is decreased.

Ultrastructural and permeability features of microvessels in the periventricular area of senescence-accelerated mice (SAM).

Brain transfer of intravenously injected horseradish peroxidase (HRP) and the ultrastructural features of the vessels were examined in periventricular areas in senescence-accelerated mice (SAMP8), which show age-related deficits in learning and memory, and senescence-accelerated resistant mice (SAMR1), which do not show age-related deficits. In all mice examined with light microscopy, staining reaction for HRP was seen in the periventricular area adjacent to the medial side of the lateral ventricle. Electron microscopic examination in the periventricular area of young and old mice of both strains showed that the staining reaction for HRP appeared in the vesicular profiles of the endothelial cytoplasm, the cytoplasm of the perivascular cells, the basal lamina, and the adjoining extracellular spaces of the white matter, suggesting an incomplete blood-brain barrier (BBB) in the periventricular white matter. In addition, irregularly thickened endothelial cell cytoplasm, membranous inclusions within the basal lamina, and electron-dense endothelial cell cytoplasm were occasionally seen in aged SAMP8 mice. These findings were not observed in 3-month-old SAMP8 mice and 3- and 13-month-old SAMR1 mice. Perivascular collagen deposits were also frequently seen in aged SAMP8 mice. These findings indicate that the endothelial cells and pericytes in the periventricular white matter in aged SAMP8 mice have an ultrastructure with damaged BBB function. Intravascular substances can easily penetrate the periventricular white matter and the BBB of the vessels in the area can be deteriorated with aging in SAMP8 mice.

Dendritic cell-like immunoreactivity in the glomerulus of the olfactory bulb and olfactory nerves of mice.

Dendritic cell-like immunoreactivity was examined in the mouse brain. The glomerulus of the olfactory bulb and the olfactory nerves were stained by antibodies against the dendritic cells, NLDC-145 and MIDC-8, while these structures were not stained by antibodies against microglia or macrophages, F4/80, Mac1 or CD45. Immunoelectron microscopy showed that the immunoreaction for NLDC-145 was localized to the sheath and presynaptic terminals of the olfactory nerves. These findings suggest that the sheath and presynaptic terminals of the primary olfactory nerves have some degree of the antigenicity in common with dendritic cells.

HDlive imaging of intra-amniotic umbilical vein varix with thrombosis.

We present a case of intra-amniotic umbilical vein varix with thrombosis using conventional two-dimensional (2D) sonography, power Doppler, three-dimensional (3D) HD-flow, and HDlive at 35 weeks of gestation. 2D sonography showed a large banana-like umbilical cord enlargement (100 × 43.3 × 45.9 mm) including umbilical vein varix (maximum vein diameter = 25.5 mm) with massive thrombosis. Power Doppler and 3D HD-flow revealed bidirectional turbulent blood flow inside the varix. The HDlive clearly demonstrated fragile massive thrombosis inside the varix. Elective cesarean section was performed on the same day in order to avoid additional risks of umbilical cord complications and umbilical venous embolism. A male infant weighing 2501 g was delivered with an umbilical artery pH of 7.334, and Apgar score of 8/9 at 1 and 5 min, respectively. The macroscopic and microscopic findings revealed umbilical cord vein varix with thrombosis. On the basis of the laboratory date of the neonate, the diagnosis of consumptive coagulopathy was made. However, the neonate followed a favorable course after delivery.

Oxidative damage in cerebral vessels of diabetic db/db mice.

BACKGROUND: Oxidative stress in diabetes mellitus has recently received increasing attention as it has been proven to be associated with the development of diabetic vascular complications. Our aim was to examine whether microvascular changes, including oxidative damage, were induced in the brains of diabetic animals. METHODS: The expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, the binding of cationized ferritin, a marker for evaluating endothelial glycocalyx, to the endothelial cells of capillaries and vascular permeability of intravenously injected horseradish peroxidase were examined in the cortices of 12- and 20-week-old db/db and db/+m mice. RESULTS: Immunostaining for 8-OHdG was clearly seen in the vessels of the cortex of 20-week-old db/db mice, but was hardly seen in those of mice in the other groups. The immunopositive area of 8-OHdG was significantly increased in the cortex of 20-week-old db/db mice compared with that of 20-week-old db/+m mice. No extravasated leakage of horseradish peroxidase was seen in any groups of mice, while the numbers of cationized ferritin particles binding to the endothelial cells was significantly decreased in 12- and 20-week-old db/db mice compared with that of db/+m mice at the same age, respectively. CONCLUSION: These findings suggest that changes in endothelial glycocalyx are induced in db/db mice and, in addition, the long-term diabetic condition of these mice induces oxidative DNA damage to the cerebral vessels.

Transferrin microheterogeneity in fetal blood.

OBJECTIVES: To investigate the distribution of microheterogeneous subfractions of transferrin in fetal blood and the influence of highly sialylated transferrins on fetal growth. STUDY METHOD: Serum transferrin concentrations were determined by a standard turbidimetric assay. Microheterogeneous transferrin subfractions were assessed by crossed immunoisoelectric focusing. RESULTS: In normal term infants, total serum transferrin concentrations and percent distribution of highly sialylated transferrins (> or = 5-sialo-transferrins) were markedly lower; the percent distributions of hyposialylated transferrins (0- and 1-sialo-transferrins) were apparently higher than those in non-pregnant and pregnant women. There was no significant positive correlation between the serum concentrations of total transferrin or highly sialylated transferrins in infants' blood and birth weights (r = 0.187, p = 0.582; r = 0.374, p = 0.257, respectively). CONCLUSION: The transferrin microheterogeneity pattern shifted towards reduced glycosylation and sialylation in addition to a decrease in total transferrin concentration in fetal blood compared to that of non-pregnant and pregnant women. The concentrations of serum total transferrin and the highly sialylated transferrins in fetal blood, if higher than a certain level, did not seem to have any influence on normal fetal growth.

Blood-brain barrier permeability in the periventricular areas of the normal mouse brain.

The main objective of this study was to assess the blood-brain barrier (BBB) permeability in periventricular areas of the normal mouse brain to test the hypothesis that the fragility of the BBB in periventricular areas may play a role in periventricular white matter lesions. Vascular permeability to intravenously injected horseradish peroxidase (HRP) was examined in the periventricular areas of adult mouse brain using light and electron microscopy. Staining for HRP appeared in the periventricular area adjacent to medial side of the lateral ventricle as well as in BBB-free areas, in the lateral septal nucleus, in the medial portion of the hippocampus and in the dorsal portion of the thalamus. In addition, the staining for HRP appeared in ependymal cell layer located near the choroid plexus and was found early after HRP injection in the wall of some vessels located at medial side of the optic tract. Ultrastructural examination of the vessel wall revealed that staining for HRP in the perfusion-fixed mice after circulation of the tracer for 5 min appeared in the perivascular space, in the basal lamina, in several vesicular profiles of the endothelial cell cytoplasm including abluminal pits, in vesicular profiles of perivascular cells and in the adjacent extracellular space. In the mice perfusion-fixed after HRP circulation for 90 min, staining for HRP in the vessels at medial side of the optic tract appeared in the cytoplasm of the perivascular cells, in vesicular structures of the endothelial cell cytoplasm such as plasmalemmal vesicles, endosomes and multivesicular bodies and occasionally in the vascular basal lamina. No clear staining reaction for HRP was found in the periventricular areas adjacent to lateral side of the lateral ventricles. These findings indicate that the BBB in the periventricular area adjacent to medial side of the lateral ventricle near the root of the choroid plexus is not so tight as it is in the cortex or in the lateral periventricular areas, and suggest that the perivascular cells play a scavenger role in the periventricular area as a component of the BBB. In addition, they indicate that blood-borne macromolecules can also invade the areas adjacent to the ventricles such as the lateral septal nucleus, the medial portion of the hippocampus and the dorsal portion of the thalamus.

Subclassification of small-for-gestational-age fetus using fetal Doppler velocimetry.

Our purpose was to determine whether small-for-gestational-age (SGA) fetus can be divided to subclassified groups using fetal Doppler velocimetry. Fifty-four pregnant women with SGA infant delivered after 37 weeks of gestation were studied. After 24 weeks of gestation, fetal middle cerebral artery puslatility index (MCAPI) and umbilical artery pulsatility index (UAPI) were measured at 2- to 3-week intervals using Doppler ultrasound. Perinatal outcomes [operative delivery due to fetal distress, abnormal fetal heart rate (FHR) pattern, meconium staining, low Apgar score (<7), neonatal acidosis (umbilical artery blood pH <7.15), neonatal intensive care unit (NICU) admission due to neonatal asphyxia, and decreased amniotic fluid] were compared in subclassified SGA groups using fetal Doppler velocimetry. The number of SGA fetuses with normal MCAPI and UAPI (normal SGA group) was 39, and those with significantly low MCAPI but normal UAPI (eventful SGA group) 15, respectively. Birth age and birth weights in the eventful SGA group were significantly earlier and lower than those in the normal SGA group, respectively (p < 0.05, and p < 0.005). There were significant increases in operative deliveries, abnormal FHR patterns and decreased amniotic fluid in eventful SGA group, when compared with events related to normal SGA group. However, there were no significant differences in meconium staining of amniotic fluid, low Apgar score, neonatal acidosis, and NICU admission between the two groups. These results suggest that SGA fetus with abnormally low MCAPI but normal UAPI has more poor perinatal outcomes, compared with that with normal MCAPI and UAPI.