Developmental Disturbance of the Cerebral Cortex of Mouse Offspring from Dams Treated with Ochratoxin A during Pregnancy

ABSTRACT  This study was designed to elucidate long-term pathological effects of ochratoxin A, one of the food contaminating mycotoxins, on the developing brain in mice. A single intraperitoneal injection of ochratoxin A at a dose of 2 or 3 mg/kg was given to pregnant mice on day 10 of gestation. They were allowed to give birth and the offspring were examined 6 weeks after birth. Their body weight, brain weight, brain size, thickness and cell packing density of dorsal neo-cortex in histological sections were examined. Growth of basal dendrites of pyramidal neurons in the layer V of dorsal neocortex was also examined with Golgi-Cox specimens in terms of number of dendrites directly arising from the perikaryon, number of endings of dendrites, branching index (No. of endings/No. of arisings), mean distance from the perikaryon to the tips of dendrites, and number of intersections of dendrites with the zonal boundaries.
Significant changes were found in brain weight, anteroposterior length of cerebrum, mean distance from the perikaryon to the tips of dendrites and number of intersections of dendrites with the zonal boundaries. These parameters can be recommended as sensitive ones in order to estimate rather weak effects of cyto-toxic chemical agents exposed in utero on the development of cerebral cortex.     

Histological maturation of astroglial cells in the archicortex of young hypothyroid rats

The maturation of fibrous astrocytes was studied in the archicortex (hippocampus) of rats rendered hypothyroid by perinatal administration of propylthiouracil (PTU). A decrease in the number of protoplasmic processes and end-feet in fibrous astrocytes from the cortical molecular layer was observed. The diameter of the perikaryon and length of the prolongations were also decreased. In animals rehabilitated after weaning, the diameter of the perikaryon and length of protoplasmic processes returned to normal while that of number of prolongations per astroglial cell remained unchanged. It is postulated that hypothyroidism induced immediately after birth impairs differentiation of astroglia in the archicortex of the rat brain, probably as a response secondary to altered neuronal and capillary development.     

Histological maturation of the neocortex in phenylketonuric rats

The histological maturation of pyramidal cells from the deeper layer of the neocortex was studied in phenylketonuric rats. The main alterations consist of a decrease in the number of span and dendritic basilar processes of large pyramidal cells, and changes in the structural organization of the cerebral cortex. It is postulated that high levels of phenylalanine induced immediately after birth disturb profoundly the process of neuronal maturation in the neocortex of the rat brain, probably with long-term effects.     

Five‐year follow‐up of prematurely born children with postnatally developing caudothalamic cysts

Aim: To assess the long‐term developmental outcome of very low birth weight children with postnatally developing caudothalamic cysts. Methods: Five very low birth weight children with postnatal caudothalamic cysts were examined using cranial ultrasound and brain Magnetic Resonance Imaging as neonates, the Bayley Scales of Infant Development, 2nd edition, and the Hammersmith Infant Neurological Examination at 2 years of corrected age, and with the Wechsler Preschool and Primary Scale of Intelligence‐Revised and the standardization version of NEPSY II at 5 years of age. The Magnetic Resonance Imaging of the brain was repeated at 5 years of age. The developmental outcome at 5 years of age was compared with that of 23 very low birth weight children with normal brain structure. Results: A cognitive level below normal and/or neuropsychological impairments was seen in all the children with caudothalamic cysts as well as in those with normal brain structure. Conclusion: Very low birth weight children with postnatally developing caudothalamic cysts had cognitive and neuropsychological impairments similar to very low birth weight children without such cysts.     

Long-lasting Effect of Maternal Hyperphenylalaninemia during Pregnancy on Postnatal Brain Development of Mice: Biochemical and Morphological Studies

Abstract The effect of maternal hyperphenylalaninemia on postnatal brain development was examined. Maternal hyperphenylalaninemia was induced by giving chow supplemented with 6% phenylalanine (Phe.) and 0.12% p-chlorophenylalanine (PCPA) for at least one month before coupling and then throughout pregnancy. Offspring from hyperphenylalaninemic mothers were given a normal diet from the first day after birth.
Infant mice were killed on the 21st, 28th and 56th day after birth. The protein, RNA and DNA in the brain were measured to determine the biochemical changes. Maturation of the dendrite of pyramidal cells was also examined by the Golgi method. The body weight of the offspring born to mothers, which had been treated with Phe. and PCPA during pregnancy, was significantly less than that of the control. The gain of cerebral weight showed a similar pattern with that to the body weight.
The total protein, RNA and DNA contents in the cerebrum of the treated group were also reduced significantly on 21st, 28th and 56th days after birth. The dendritic arborization of the cortical pyramidal neurons in the layer V showed significant reductions in the offspring born to hyperphenylalaninemic mothers compared with the age-matched control at 21, 28 and 56 days after birth.
These findings suggest that maternal hyperphenylalaninemia during pregnancy causes an irreversible retardation of the neuronal maturation both biochemically and morphologically, and subsequently gives rise to disorders of the higher cortical functions.     

Constructing the human cerebral cortex during infancy and childhood: Types and numbers of cortical columns and numbers of neurons in such columns at different age-points

This study examines JL Corel's data on neuron numbers in 35 human cortical areas for eight age points from 0 (birth) to 72 months, to analyze cortical columns, the presumed functional units of the cortex. For each cortical area at each age point, cortical surface divided by the square root of the area's neuron number gives cross-sectional areas with radii ranging from 180 um at birth to 250 pm at 72 months. For the prefrontal cortex at birth and 48 months, these radii are approximately 2.10 and 1.19 times the longest radial basal dendrites, suggesting similar dimensions between these two measures of column radius. The logarithm of neuron number per cortical area and age point was examined in relation to the Weber-Fechner law governing the relationship between stimulus intensity and perception. A mechanism for this law consistent with the cortical model of Douglas et al. illustrates the importance of local circuit neurons. The cross-sectional areas of hexagonal columns for prefrontal cortex, using as radius, the longest radial extent of layer 5 pyramidal neuron basal dendrites, ranging from 0.013 mm- at birth to 0.064 mm² at 48 months, suggests that functional cortical columns increase cross-sectional area during development. These cross-sectional areas are55–100-fold larger at birth, and229–277-fold larger at 48 months, than those computed from somal width in prefrontal, layer 5 pyramidal neurons. Comparison of radial extent of pyramidal basal dendrites to their soma-to-soma distances shows that layer 3 pyramidal basal dendrites reach 1.5 and 4.0 other pyramidal neurons at 15 and 60 months, respectively, while layer 5, extra-large pyramidal basal dendrites reach 1.14 and 1.72 other such neurons at birth and 48 months, respectively. If such a relationship holds for other cortical areas, then the Conel data can be used to estimate basal dendrite extent, for which there currently is a paucity of data.     

Enzyme-replacement therapy from birth delays the development of behavior and learning problems in mucopolysaccharidosis type IIIA mice

Mucopolysaccharidosis type IIIA (MPS IIIA; Sanfilippo syndrome) is a lysosomal storage disorder characterized by severe CNS degeneration, resulting in behavioral abnormalities and loss of learned abilities. Early treatment is vital to prevent long-term clinical pathology in lysosomal storage disorders. We have used naturally occurring MPS IIIA mice to assess the effects of long-term enzyme-replacement therapy initiated either at birth or at 6 wk of age. MPS IIIA and normal control mice received weekly i.v. injections of 1 mg/kg recombinant human sulfamidase until 20 wk of age. Sulfamidase is able to enter the brain until the blood-brain barrier completely closes at 10-14 d of age. MPS IIIA mice that were treated from birth demonstrated normal weight, behavioral characteristics, and ability to learn. MPS IIIA mice that were treated from birth performed significantly better in the Morris water maze than MPS IIIA mice that were treated from 6 wk of age or left untreated. A reduction in storage vacuoles in cells of the CNS in MPS IIIA mice that were treated from birth is consistent with the improvements observed. These data suggest that enzyme that enters the brain in the first few weeks of life, before the blood-brain barrier matures, is able to delay the development of behavior and learning difficulties in MPS IIIA mice.     

小鼠血脑屏障发育的超微结构观察

目的 探讨小鼠血脑屏障(BBB)的发育特点.方法 取出生第1天、第14天、第28天、第42天各2只昆明小鼠脑组织顶叶,切成1 mm×1 mm×1 mm小块,30 mL·L-1戊二醛和15g· L-1多聚甲醛前固定,10mL·L-1锇酸和15 mL· L-1亚铁氰化钾后固定,乙醇、丙酮脱水,环氧树脂618包埋剂包埋；超薄切片,醋酸铀、柠檬酸铅染色,在日立Hu - 12A型透射电镜下观察出生后不同天数小鼠BBB的生长发育特点.结果 出生第1天、第14天、第28天、第42天昆明小鼠BBB的脑毛细血管内皮、内皮细胞间的紧密连接、基膜、星形胶质细胞突起(胶质膜)等超微结构呈现明显差异.出生第1天脑组织内微血管壁厚,未见完整基膜,仅见到围绕毛细血管周围,呈不连续性、厚度和电子密度不均的基膜样物质,神经元及胶质细胞胞体靠近内皮细胞；随着生长发育,出生第14天、第28天昆明小鼠微血管壁变薄,基膜逐渐清晰完整；至出生第42天,昆明小鼠BBB进一步发育,基膜厚且密度高,神经元及胶质细胞胞体远离血管.结论 新生小鼠BBB未发育成熟,是易发脑损伤的一个关键环节.     

The effects of prenatal exposure to ethinyl estradiol and bisphenol-A on the developing brain, reproductive organ and behavior of mouse

ABSTRACT This study investigated the effects of ethinyl estradiol (EE) and bisphenol‐A (BPA) on the maturation of fetuses, reproductive organ, brain development, and behavior. Twenty‐eight Jcl‐ICR pregnant mice were divided into 0.2 mg/kg of EE, 0.02 mg/kg of EE, BPA and control groups. Pregnant mice belonging to 0.2 mg/kg of EE and 0.02 mg/kg of EE group were daily injected subcutaneously either 0.2 mg/kg or 0.02 mg/kg of EE dissolved in olive oil from 11 to 19 days of gestation. The BPA group received an injection of 100 mg/kg of BPA dissolved in olive oil while the control group received an injection of olive oil alone subcutaneously on the same days of gestation. Neurological and behavioral development was examined by means of the sensorimotor reflexes until day 10 and openfield test on day 40 after birth. Myelination of the brain and maturation of testis were histologically examined. Obtained results were: 1) Pregnant mice in the 0.2 mg/kg EE group had no live births. 2) The mean litter size in the 0.02 mg/kg EE group was smaller than that in the BPA and control groups. The mean body weight at birth and that at the age of 60 days showed no significant differences among groups. 3) In the openfield test at the age of 40 days, the mean number of grooming and line‐crossing in the inner field in the 0.02 mg/kg EE group were significantly higher than those in the control group and the mean number of grooming, rearing and line‐crossing in the outer field in 0.02 mg/kg EE group were significantly higher than those in the BPA group. The mean numbers of defecation in both 0.02 mg/kg EE group and BPA group were less than those in the control group. 4) The mean diameter of seminiferous tubules and number of spermatocytes layers in the 0.02 mg/kg EE group and BPA were significantly less than those in the control group. 5) The mean diameter of tractus mamillothalamics in the 0.02mg/kg EE group and BPA group showed no significant differences compared with that in the control group. These findings suggested that prenatal exposure to EE or BPA adversely affects litter size, openfield behavior and spermatogenesis.     

Biochemical Studies on the Effect of Maternal Hyperphenyl-alaninemia on Fetal Brain Maturation of Mice

Abstract The effects of maternal hyperphenylalaninemia during pregnancy on the biochemical maturation of neonatal mice brains were examined, thus establishing the critical concentration of phenylalanine in maternal blood and the critical period of maternal hyperphenylalaninemia during pregnancy. Hyperphenylalaninemia was induced by giving chow supplemented with 3%, 4%, 5%, or 6% phenylalanine (Phe.) and 0.12% p-chlorophenylalanine (PCPA) for at least one month and then throughout pregnancy. Some of the pregnant mice fed the 6% Phe. diet before pregnancy received a normal diet after conception (6%: A).
Offspring from each group were decapitated two days after birth. Their brains were removed and then divided into the cerebrum and the brain stem including the cerebellum. Total protein, RNA and DNA were measured biochemically. All kinds of markers of the newborn mice born to the 5% and 6% mothers, the weight and the contents of the protein, RNA and DNA, were reduced significantly in both the cerebrum and brain stem. In the 4% group, however, only the brain stem was affected. The 3% group showed reductions neither in the weight nor the protein and nucleic acids contents in both the cerebrum and brain stem. In the 6%:A group, in which the diet was returned to normal just after conception, total protein, RNA and DNA were reduced in the brain stem, but not in the cerebrum.
These results suggest that the critical concentration of maternal blood phenylalanine during pregnancy in the mouse is 11mg/dl, which is that corresponding to the 3% group, and also suggest that it is too late to begin the low phenylalanine diet after conception.     

Dendritic development in the neocortex of adult rats subjected to postnatal malnutrition

The Golgi-Cox method was used to study the maturation of the large pyramidal cells of the Vth cortical layer in two groups of adult rats, one subjected to early postnatal malnutrition and another malnourished only during the second month of life. The main alterations were observed in the pyramidal cells of cortical layer V of rats malnourished during the first month of life. They consist of a decrease in the number and span of dendritic basilar processes. In animals malnourished during the second month of life, the number and span of basilar dendritic processes in pyramidal cells of layer V, were normal. It is postulated that early postnatal malnutrition induced immediately after birth, profoundly disturbs the process of neuronal maturation in the neocortex of the rat brain, probably with permanent effects.     

Effects of bifidobacterium breve supplementation on intestinal flora of low birth weight infants

BACKGROUND: It is known that the bifidobacteria flora play important roles in mucosal host defense and can prevent infectious diseases. Because bacterial populations develop during the first day of life, the authors examined whether the early administration of bifidobacteria has a positive effect on the health of low birth weight infants. METHODS: The effects of oral administration of Bifidobacterium breve (B. breve) supplements were studied in a controlled trial with low birth weight infants (average birth weight 1489 g). The infants were divided into three groups: Group A and B received a dose of 1.6 x 10(8) cells of B. breve supplement twice a day, commencing either from several hours after birth (group A) or 24 h after birth (group B). Group C, the control group, received no supplement. RESULTS: There were no significant differences in birth weight, treatment with antibiotics, and the starting time of breast-feeding among the three groups. A Bifidobacterium-predominant flora was formed at an average of 2 weeks after birth in group A and at an average of 4 weeks after birth in group B, while no Bifidobacterium was isolated in eight out of 10 infants in group C during the observation period of 7 weeks. In comparison between group A and B, Bifidobacterium was detected significantly earlier in group A, and the number of Enterobacteriaceae present in the infants at 2 weeks after birth was significantly lower in group A. CONCLUSION: The results of the present study suggest that very early administration of B. breve to low birth weight infants is useful in promoting the colonization of the Bifidobacterium and the formation of a normal intestinal flora.     

Maternal administration of bisphenol A alters the microglial profile in the neocortex of mouse weanlings

Bisphenol A (BPA) is known to cause abnormal neurogenesis in the developing neocortex. The mechanisms of BPA toxicity concerning neuroinflammatory-related endpoints are incompletely characterized. To evaluate the microglial morphology and the gene expression of pro-inflammatory cytokines in the newborn neocortex, ICR mice were exposed to BPA 200 μg/kg/d on gestational day 6 through post-partum day 21. Weanlings exposed during prenatal and postnatal period to BPA showed an increased number of amoeboid-type microglia, a microglial differentiation disruption (the M1/M2 microglial ratio), and an abnormal expression of genes encoding pro-inflammatory factors. These findings suggest that the well-known neurodevelopmental toxicity of BPA may be related to an increased microglial activation and neuroinflammation in the neocortex.     

Birth Characteristics of Childhood Cancer Cases, Controls, And Their Siblings

Reproductive characteristics of childhood cancer cases, controls, and their siblings were examined using data from a case-control study in the Denver, Colorado metropolitan area, Childhood cancer patients (n=356) diagnosed from 1976 to 1983 were identified, and 242 were interviewed. Controls were selected by random digit dialing, with 212 interviews being completed (60% of eligibles). Extremes of birth weight were more common only among brain cancer cases. Patients were more often born preterm, particularly those with brain tumors [odds ratio (OR) = 6.1; 95% confidence interval (CI), 1.6-23.4] and were more likely to have birth defect F (OR = 2.1; 95% CI, 0.9-5.0). Twins were more common among case siblings (OR = 2.6; 95% CI, 0.8-8.2). Low birth weight and preterm delivery among siblings were related only to soft tissue sarcoma. Birth defects were more common among case siblings, particularly leukemia cases (OR = 3.2; 95% CI, 1.3-7.7). Previous reports of elevated birth weight among cases and increased risk of miscarriage in case mothers were not corroborated, but associations with preterm delivery, high birth order, and birth defects among cases and birth defects and twinning among case siblings encourage additional evaluation.     

Birth Characteristics of Childhood Cancer Cases,Controls, And Their Siblings

Reproductive characteristics of childhood cancer cases, controls, and their siblings were examined using data from a case-control study in the Denver, Colorado metropolitan area, Childhood cancer patients (n=356) diagnosed from 1976 to 1983 were identified, and 242 were interviewed. Controls were selected by random digit dialing, with 212 interviews being completed (60% of eligibles). Extremes of birth weight were more common only among brain cancer cases. Patients were more often born preterm, particularly those with brain tumors [odds ratio (OR) = 6.1; 95% confidence interval (CI), 1.6–23.4] and were more likely to have birth defect F (OR = 2.1; 95% CI, 0.9–5.0). Twins were more common among case siblings (OR = 2.6; 95% CI, 0.8–8.2). Low birth weight and preterm delivery among siblings were related only to soft tissue sarcoma. Birth defects were more common among case siblings, particularly leukemia cases (OR = 3.2; 95% CI, 1.3–7.7). Previous reports of elevated birth weight among cases and increased risk of miscarriage in case mothers were not corroborated, but associations with preterm delivery, high birth order, and birth defects among cases and birth defects and twinning among case siblings encourage additional evaluation.     

Glycerokinase in brain and liver of low birth weight newborns.

Glycerokinase activity was measured in brain and liver tissue of decreased low birth weight newborns. No glycerokinase activity was found in the brain. In the liver a relatively high activity of glycerokinase was ascertained even in very immature newborns.     

Sonic hedgehog signaling coordinates the proliferation and differentiation of neural stem/progenitor cells by regulating cell cycle kinetics during development of the neocortex

Sonic hedgehog (Shh) acts as a morphogen in normal development of various vertebrate tissues and organs. Shh signaling is essential for patterning and cell-fate specification, particularly in the central nervous system. Shh signaling plays different roles depending on its concentration, area, and timing of exposure. During the development of the neocortex, a low level of Shh is expressed in the neural stem/progenitor cells as well as in mature neurons in the dorsal telencephalon. Shh signaling in neocortex development has been shown to regulate cell cycle kinetics of radial glial cells and intermediate progenitor cells, thereby maintaining the proliferation, survival and differentiation of neurons in the neocortex. During the development of the telencephalon, endogenous Shh signaling is involved in the transition of slow-cycling neural stem cells to fast-cycling neural progenitor cells. It seems that high-level Shh signaling in the ventral telencephalon is essential for ventral specification, while low-level Shh signaling in the dorsal telencephalon plays important roles in the fine-tuning of cell cycle kinetics. The Shh levels and multiple functions of Shh signaling are important for proper corticogenesis in the developing brain. The present paper discusses the roles of Shh signaling in the proliferation and differentiation of neural stem/progenitor cells.     

Brain volumes and cognitive function in very-low-birth-weight (VLBW) young adults

BackgroundPreterm born very-low-birth-weight (VLBW: birth weight ≤1500 g) survivors have increased risk of perinatal brain injury that may cause deviant brain development and later neuroimpairments, including reduced cognitive functioning.AimsIn this long-term follow up study of three year-cohorts (birth years 1986–88) of VLBW subjects and term born controls with normal birth weight, the aim was to examine differences in brain volumes at age 20 years. In addition, the relationships between brain volumes and cognitive abilities and perinatal variables were explored.MethodsForty-four VLBW subjects and 60 controls were assessed with cognitive testing (Wechsler Adult Intelligence Scale – WAIS-III) and structural MRI at 1.5 T, using the FreeSurfer 5.1 software for volumetric analysis. A subpopulation had MRI performed also at age 15, and for this group changes in brain volumes with age were examined.ResultsThe VLBW subjects had smaller brain volumes, especially of thalamus, globus pallidus and parts of the corpus callosum, and larger lateral ventricles than controls at age 20. However, no significant group differences in longitudinal change from age 15 to 20 were observed. The most immature and smallest VLBW subjects at birth, and those with the highest perinatal morbidity, showed most pronounced volume deviations. Positive associations between several brain volumes and full IQ, as well as three of four IQ indices in the VLBW group, were observed.ConclusionReduced volumes of grey and white matter and ventricular dilatation in VLBW young adults may indicate permanent effects on brain development from perinatal brain injury with influence on later cognitive function.     

Changing Panorama of Cerebral Palsy in Children of Low Birth Weight

Of 2,840 out-patients who visited the Tokyo Metropolitan Kita Rehabilitation Center in 1965, 1968, 1970, 1973, 1975 and 1978, 278 children with cerebral palsy (CP) of low birth weight were studied to analyse changes in type of CP in relation to gestational week, birth weight, perinatal factors and subsequent complications. 1. The incidence of handicap associated with low birth weight in new out-patients had not changed. 2. The number of doubly handicapped CP patients was gradually increasing while number of uncomplicated CP patients was gradually decreasing. 3. The number of children with tension athetosis was remarkably decreasing; the number of children with spastic quadriplegia was gradually increasing. Increase in number of the spastic type was found especially in the group whose birth weight was over 1,500 gm. and gestational week over 37 weeks. The numbers of spastic diplegia and hemiplegia patients had not significantly changed. 4. In the athetoid group, the complication of severe jaundice was apparently decreasing since 1970 while the number of asphyxia cases was gradually increasing. In the spastic group, there were no remarkable changes in the perinatal complications. 5. Of spastic quadriplegia patients 78.3% were of IQ of less than 67 while 33.3% of spastic hemiplegia and 23.5% of spastic diplegia patients had IQs of less than 67.31.4% of the athetoid type had IQs of less than 67. 6. In the asphyxia group, 34 of 82 children with low birth weight CP (41.5%) had epilepsy. Our results suggest that the causes of brain damage in low birth weight infants are not merely preventable perinatal factors, but are due to a more complex interaction of prenatal and perinatal factors.     

Preterm infants’ early growth and brain white matter maturation at term age

Background

Normal intrauterine conditions are essential to normal brain growth and development; premature birth and growth restriction can interrupt brain maturation. Maturation processes can be studied using diffusion tensor imaging.

Objective

The aim of this study was to use tract-based spatial statistics to assess the effect that early postnatal growth from birth to 40 gestational weeks has on brain white matter maturation.

Materials and methods

A total of 36 preterm infants were accepted in the study. Postnatal growth was assessed by weight, length and head circumference. Birth weight z-score and gestational age were used as confounding covariates.

Results

Head circumference catch-up growth was associated with less mature diffusion parameters (P?<?0.05). No significant associations were observed between weight or length growth and diffusion parameters.

Conclusion

Growth-restricted infants seem to have delayed brain maturation that is not fully compensated at term, despite catch-up growth.