Prenatal prediction of need for ventriculoperitoneal shunt in open spina bifida

OBJECTIVE

To investigate whether the need for ventriculoperitoneal shunting in neonates with open spina bifida can be predicted prenatally.

METHODS

This was a retrospective cohort study of all fetuses with open spina bifida identified at a single referral center between 1998 and 2012. Ultrasound records were reviewed and outcomes were ascertained from maternal, neonatal and pediatric records. The performance of screening was determined by receiver-operating characteristics (ROC) curve analysis.

RESULTS

We identified 124 cases of isolated open spina bifida, of which 48 were liveborn. Detailed postnatal follow-up was available for 39 cases, with an average follow-up time of 3.6 years. A shunt was inserted in 22 (56.4%) cases. The width of the posterior horn of the lateral ventricle (Vp) and the ratio between its width and that of the cerebral hemisphere (Vp/H) at diagnosis were significantly greater in cases that required a shunt compared with those that did not subsequently require a shunt (Vp: median 12.4 mm vs 7.7 mm, P < 0.001, and Vp/H: median 0.54 vs 0.33, P < 0.001, respectively). Similarly, at the last scan before delivery, Vp and Vp/H were significantly higher in those requiring a shunt (Vp: median 23.1 mm vs 8.2 mm, P < 0.001; and Vp/H: 0.54 vs 0.21, P < 0.001, respectively). Using Vp and Vp/H at the initial assessment, the rates of detection of fetuses requiring a shunt postnatally were 68.2% and 86.4% for a false-positive rate of 13%, with positive likelihood ratios of 6 and 7, respectively. All fetuses with a Vp of ≥ 12 mm or a Vp/H of ≥ 0.6 at the time of diagnosis required postnatal shunt insertion (positive predictive value = 100%).

CONCLUSIONS

In cases with open spina bifida the need for a postnatal shunt can be predicted prenatally. This novel observation should be useful in the prediction of outcome and therefore for accurate prenatal counseling and triaging cases for fetal surgery.

Oleuropein aglycone counteracts Aβ42 toxicity in the rat brain

Previous data have shown that oleuropein aglycone (OLE), the main secoiridoid phenol present in extra virgin olive oil, counteracts in vitro aggregation of the Aβ42 peptide and protects cultured cells and model organisms against aggregates toxicity. In this study we investigated the relative tissue toxicity of Aβ42 aggregated in vitro in the presence or in the absence of OLE by injecting the nucleus basalis magnocellularis (NBM) of adult male Wistar rats with a 1.5 μl solution containing OLE (450 μM) or Aβ42 (50 μM) aggregated in the absence (oligomers) or in the presence of 450 μM OLE. Control rats were injected with vehicle (1.5 μl). Thirty days after injection, the number of choline acetyltransferase (ChAT)-positive neurons, glia reaction and the Aβ peptide levels were detected by immunohistochemistry. An apparent reduction in the amount of soluble A11-positive oligomers was detected in the NBM injected with Aβ42 aggregated with OLE, as compared with the NBM injected with Aβ42 alone. In the latter case, the number of ChAT-positive neurons was significantly reduced (≈-33%) respect to that recorded in the NBM injected with phosphate buffer, OLE or Aβ42 aggregated with OLE. A markedly attenuated Aβ-induced astrocytes and microglia reaction was also found in the NBM injected with Aβ42 aggregated with OLE. Altogether, these data provide additional support to the anti-aggregation, neuroprotective and anti-inflammatory activities of this natural phenol, confirming its beneficial properties against neurodegeneration.

Age-related impairment of olfactory bulb neurogenesis in the Ts65Dn mouse model of Down syndrome

Down syndrome (DS) is a genetic condition caused by triplication of chromosome 21. Widespread neurogenesis reduction during brain development underlies the numerous neurological defects of DS. These defects start to manifest themselves at birth and worsen with age. However, unlike other brain functions, smell is impaired only at advanced life stages, suggesting preservation of olfactory bulb neurogenesis up to adulthood. To clarify this issue, in the current study we examined olfactory bulb (OB) neurogenesis and olfactory function by exploiting the Ts65Dn mouse, a widely used model of DS. We found that in young (15-day-old) Ts65Dn mice, in spite of a reduced proliferation rate in the subventricular zone (SVZ) in comparison with euploid mice, the number of neuroblasts traveling in the rostral migratory stream (RMS), en route to the OB, and the number of new granule neurons added to the OB were similar to those of euploid mice. In mid-age (13-month-old) Ts65Dn mice, however, the proliferation rate in the SVZ was more severely reduced in comparison with euploid mice and the number of neuroblasts in the RMS and new granule neurons added to the OB underwent a reduction. While in young Ts65Dn mice the olfactory function, assessed with the buried food pellet test, was similar to that of euploid mice, in mid-age mice it was significantly impaired. Taken together, results suggest that an age-related reduction in the renewal of OB granule cells may underlie the age-related smell impairment in DS.

Prolyl carboxypeptidase mRNA expression in the mouse brain

Prolyl carboxypeptidase (PRCP), a serine protease, is widely expressed in the body including liver, lung, kidney and brain, with a variety of known substrates such as plasma prekallikrein, bradykinin, angiotensins II and III, and α-MSH, suggesting its role in the processing of tissue-specific substrates. In the brain, PRCP has been shown to inactivate hypothalamic α-MSH, thus modulating melanocortin signaling in the control of energy metabolism. While its expression pattern has been reported in the hypothalamus, little is known on the distribution of PRCP throughout the mouse brain. This study was undertaken to determine PRCP expression in the mouse brain. Radioactive in situ hybridization was performed to determine endogenous PRCP mRNA expression. In addition, using a gene-trap mouse model for PRCP deletion, X-gal staining was performed to further determine PRCP distribution. Results from both approaches showed that PRCP gene is broadly expressed in the brain.

Adolescent drinking targets corticotropin-releasing factor peptide-labeled cells in the central amygdala of male and female rats

Adolescence is a developmental period when many teenagers first drink alcohol and often engage in binge drinking. Early onset of alcohol is linked to increased risk of stress-related disorders in adulthood in humans, suggesting that alcohol may interfere with development of the stress regulatory system. We investigated the effect of voluntary alcohol exposure on corticotropin-releasing factor (CRF) peptide-producing cells in the central nucleus of the amygdala (CeA) in adolescent male and female rats. These cells are important for the autonomic and behavioral responses to stress, have been implicated in addiction, and change over adolescent development. Animals self-administered sweetened alcohol during early adolescence (postnatal days (PDs) 28-42) and brains were obtained on PD 43 for CRF peptide immunolabeling. Females had fewer CRF immunoreactive (-ir) cells in the CeA compared to males. In both males and females, alcohol self-administration reduced the number of CRF-ir cells in the CeA compared to control conditions in which rats self-administered equivalent levels of sweetened water that did not contain alcohol. Reduced peptide labeling was not observed in the bed nucleus of the stria terminalis, indicating regional specificity of these changes. Alterations within the CRF cell population of the amygdala may have important implications for susceptibility to alcohol and stress disorders during adolescence and later on in life.

Effects of hypocretin and norepinephrine interaction in bed nucleus of the stria terminalis on arterial pressure

Forebrain neuronal circuits containing hypocretin-1 (hcrt-1) and norepinephrine (NE) are important components of central arousal-related processes. Recently, these two systems have been shown to have an overlapping distribution within the bed nucleus of the stria terminalis (BST), a limbic structure activated by stressful challenges, and which functions to adjust arterial pressure (AP) and heart rate (HR) to the stressor. However, whether hcrt-1 and NE interact in BST to alter cardiovascular function is unknown. Experiments were done in urethane-α-chloralose anesthetized, paralyzed, and artificially ventilated male Wistar rats to investigate the effect of hcrt-1 and NE on the cardiovascular responses elicited by l-glutamate (Glu) stimulation of BST neurons. Microinjections of hcrt-1, NE or tyramine into BST attenuated the decrease in AP and HR to Glu stimulation of BST. Additionally, combined injections of hcrt-1 with NE or tyramine did not elicit a greater attenuation than either compound alone. Furthermore, injections into BST of the α2-adrenergic receptor (α2-AR) antagonist yohimbine, but not the α1-AR antagonist 2-{[β-(4-hydroxyphenyl)ethyl]aminomethyl}-1-tetralone hydrochloride, blocked both the hcrt-1 and NE-induced inhibition of the BST cardiovascular depressors responses. Finally, injections into BST of the GABAA receptor antagonist bicuculline, but not the GABAB receptor antagonist phaclofen, blocked the hcrt-1 and NE attenuation of the BST Glu-induced depressor and bradycardia responses. These data suggest that hcrt-1 effects in BST are mediated by NE neurons, and hcrt-1 likely acts to facilitate the synaptic release of NE. NE neurons, acting through α2-AR may activate Gabaergic neurons in BST, which in turn through the activation of GABAA receptors inhibit a BST sympathoinhibitory pathway. Taken together, these data suggest that hcrt-1 pathways to BST through their interaction with NE and Gabaergic neurons may function in the coordination of cardiovascular responses associated with different behavioral states.

Lesion of the commissural nucleus of the solitary tract/A2 noradrenergic neurons facilitates the activation of angiotensinergic mechanisms in response to hemorrhage

In the present study, we investigated the effects of lesions of A2 neurons of the commissural nucleus of the solitary tract (cNTS) alone or combined with the blockade of angiotensinergic mechanisms on the recovery of arterial pressure (AP) to hemorrhage in conscious rats. Male Holtzman rats (280-320g) received an injection of anti-dopamine-beta-hydroxylase-saporin (12.6ng/60nl; cNTS/A2-lesion, n=28) or immunoglobulin G (IgG)-saporin (12.6ng/60nl, sham, n=24) into the cNTS and 15-21days later had a stainless steel cannula implanted in the lateral ventricle. After 6days, rats were submitted to hemorrhage (four blood withdrawals, 2ml/300g of body weight every 10min). Both cNTS/A2-lesioned and sham rats had similar hypotension to hemorrhage (-62±7 and -73±7mmHg, respectively), however cNTS/A2-lesioned rats rapidly recovered from hypotension (-5±3mmHg at 30min), whereas sham rats did not completely recover until the end of the recording (-20±3mmHg at 60min). Losartan (angiotensin type 1 receptor antagonist) injected intracerebroventricularly (100μg/1μl) or intravenously (i.v.) (10mg/kg of body weight) impaired the recovery of AP in cNTS/A2-lesioned rats (-24±6 and -35±7mmHg at 30min, respectively). In sham rats, only i.v. losartan affected the recovery of AP (-39±6mmHg at 60min). The results suggest that lesion of the A2 neurons in the cNTS facilitates the activation of the angiotensinergic pressor mechanisms in response to hemorrhage.

Early postnatal GFAP-expressing cells produce multilineage progeny in cerebrum and astrocytes in cerebellum of adult mice

Early postnatal GFAP-expressing cells are thought to be immature astrocytes. However, it is not clear if they possess multilineage capacity and if they can generate different lineages (astrocytes, neurons and oligodendrocytes) in the brain of adult mice. In order to identify the fate of astroglial cells in the postnatal brain, hGFAP-Cre-ER(T2) transgenic mice were crossed with the R26R Cre reporter mouse strains which exhibit constitutive expression of β-galactosidase (β-gal). Mice carrying the hGFAP-Cre-ER(T2)/R26R transgene were treated with Tamoxifen to induce Cre recombination in astroglial cells at postnatal (P) day 6 and Cre recombinase-expressing cells were identified by X-gal staining. Immunohistochemical staining was used to identify the type(s) of these reporter-tagged cells. Sixty days after recombination, X-gal-positive cells in different cerebral regions of the adult mice expressed the astroglial markers Blbp and GFAP, the neuronal marker NeuN, the oligodendrocyte precursor cell marker NG2 and the mature oligodendrocyte marker CC1. X-gal-positive cells in the cerebellum coexpressed the astroglial marker Blbp, but not the granule cell marker NeuN, Purkinje cell marker Calbindin or oligodendrocyte precursor cell marker NG2. Our genetic fate mapping data demonstrated that early postnatal GFAP-positive cells possessed multilineage potential and eventually differentiated into neurons, astrocytes, and oligodendrocyte precursor cells in the cerebrum and into astrocytes (including Bergmann glia) in the cerebellum of adult mice.

Day-night differences in neural activation in histaminergic and serotonergic areas with putative projections to the cerebrospinal fluid in a diurnal brain

In nocturnal rodents, brain areas that promote wakefulness have a circadian pattern of neural activation that mirrors the sleep/wake cycle, with more neural activation during the active phase than during the rest phase. To investigate whether differences in temporal patterns of neural activity in wake-promoting regions contribute to differences in daily patterns of wakefulness between nocturnal and diurnal species, we assessed Fos expression patterns in the tuberomammillary (TMM), supramammillary (SUM), and raphe nuclei of male grass rats maintained in a 12:12 h light-dark cycle. Day-night profiles of Fos expression were observed in the ventral and dorsal TMM, in the SUM, and in specific subpopulations of the raphe, including serotonergic cells, with higher Fos expression during the day than during the night. Next, to explore whether the cerebrospinal fluid is an avenue used by the TMM and raphe in the regulation of target areas, we injected the retrograde tracer cholera toxin subunit beta (CTB) into the ventricular system of male grass rats. While CTB labeling was scarce in the TMM and other hypothalamic areas including the suprachiasmatic nucleus, which contains the main circadian pacemaker, a dense cluster of CTB-positive neurons was evident in the caudal dorsal raphe, and the majority of these neurons appeared to be serotonergic. Since these findings are in agreement with reports for nocturnal rodents, our results suggest that the evolution of diurnality did not involve a change in the overall distribution of neuronal connections between systems that support wakefulness and their target areas, but produced a complete temporal reversal in the functioning of those systems.

A circuitry and biochemical basis for tuberous sclerosis symptoms: from epilepsy to neurocognitive deficits

Tuberous sclerosis complex (TSC) is an autosomal dominant monogenetic disorder that is characterized by the formation of benign tumors in several organs as well as brain malformations and neuronal defects. TSC is caused by inactivating mutations in one of two genes, TSC1 and TSC2, resulting in increased activity of the mammalian Target of Rapamycin (mTOR). Here, we explore the cytoarchitectural and functional CNS aberrations that may account for the neurological presentations of TSC, notably seizures, hydrocephalus, and cognitive and psychological impairments. In particular, recent mouse models of brain lesions are presented with an emphasis on using electroporation to allow the generation of discrete lesions resulting from loss of heterozygosity during perinatal development. Cortical lesions are thought to contribute to epileptogenesis and worsening of cognitive defects. However, it has recently been suggested that being born with a mutant allele without loss of heterozygosity and associated cortical lesions is sufficient to generate cognitive and neuropsychiatric problems. We will thus discuss the function of mTOR hyperactivity on neuronal circuit formation and the potential consequences of being born heterozygous on neuronal function and the biochemistry of synaptic plasticity, the cellular substrate of learning and memory. Ultimately, a major goal of TSC research is to identify the cellular and molecular mechanisms downstream of mTOR underlying the neurological manifestations observed in TSC patients and identify novel therapeutic targets to prevent the formation of brain lesions and restore neuronal function.

Lateral ventricular meningioma presenting with intraventricular hemorrhage: a case report and literature review

Lateral ventricular meningiomas presenting with primary intraventricular hemorrhage are extremely uncommon. We report here a case of primary intraventricular hemorrhage attributable to a lateral ventricular meningioma. This case concerns a 46-year-old female patient who presented with sudden onset of headache. Computed tomography (CT), computed tomography angiography (CTA) and magnetic resonance imaging (MRI) examinations showed hemorrhage from a ruptured tumor mass, which was pathologically confirmed as a transitional meningioma. The patient underwent surgical treatment and had a good prognosis. A retrospective review of eight previous cases of hemorrhage from ruptured lateral ventricular meningiomas revealed that hemorrhage of lateral ventricular meningiomas and hemorrhage of meningiomas at other intracranial sites have similar causes. The clinical and pathological features of ruptured lateral ventricular meningiomas are consistent with those of unruptured lateral ventricular meningiomas. As this clinical entity is extremely rare, attention is called for while performing differential diagnosis.

Effects of abstinence on brain morphology in alcoholism: a MRI study

Chronic alcohol abuse leads to morphological changes of the brain. We investigated if these volumetric changes are reversible after a period of abstinence. For this reason 41 male and 15 female alcohol patients underwent MRI-scanning after in-patient detoxification (baseline) entering alcoholism treatment programs, and between 6 and 9 months later (follow-up), in a phase of convalescence. Additionally, 29 male and 16 female control subjects were examined. The MRI-scans were delineated and the resulting regions of interest, volumes of lateral ventricles and prefrontal lobes were expressed relatively to total brain volume. Compared to control subjects alcohol patients showed bilaterally decreased prefrontal lobes (11% reduction) and increased lateral ventricles (up to 42% enlargement). The extent of the ventricular increase was depending on patient's additional psychiatric diagnosis, showing smaller lateral ventricles in patients with additional personality disorder. While at follow-up the size of prefrontal lobes remained unchanged, volumes of the lateral ventricles decreased (5-6% reduction) in alcohol patients with abstinence and improved drinking behavior, especially in patients that underwent only one detoxification. The extent of the ventricular enlargement correlated with the elevation of alcohol related laboratory measures (mean corpuscular volume, gamma-glutamyl transpeptidase). In conclusion this study confirms the hypothesis that alcoholism causes brain damages that are partially reversible. It should be analyzed in further studies with larger sample sizes, if complete brain regeneration is possible maintaining abstinence over a longer period.

Prenatal mild ventriculomegaly predicts abnormal development of the neonatal brain

BACKGROUND

Many psychiatric and neurodevelopmental disorders are associated with mild enlargement of the lateral ventricles thought to have origins in prenatal brain development. Little is known about development of the lateral ventricles and the relationship of prenatal lateral ventricle enlargement with postnatal brain development.

METHODS

We performed neonatal magnetic resonance imaging on 34 children with isolated mild ventriculomegaly (MVM; width of the atrium of the lateral ventricle >/= 1.0 cm) on prenatal ultrasound and 34 age- and sex-matched control subjects with normal prenatal ventricle size. Lateral ventricle and cortical gray and white matter volumes were assessed. Fractional anisotropy (FA) and mean diffusivity (MD) in corpus callosum and corticospinal white matter tracts were determined obtained using quantitative tractography.

RESULTS

Neonates with prenatal MVM had significantly larger lateral ventricle volumes than matched control subjects (286.4%; p < .0001). Neonates with MVM also had significantly larger intracranial volumes (ICV; 7.1%, p = .0063) and cortical gray matter volumes (10.9%, p = .0004) compared with control subjects. Diffusion tensor imaging tractography revealed a significantly greater MD in the corpus callosum and corticospinal tracts, whereas FA was significantly smaller in several white matter tract regions.

CONCLUSIONS

Prenatal enlargement of the lateral ventricle is associated with enlargement of the lateral ventricles after birth, as well as greater gray matter volumes and delayed or abnormal maturation of white matter. It is suggested that prenatal ventricle volume is an early structural marker of altered development of the cerebral cortex and may be a marker of risk for neuropsychiatric disorders associated with ventricle enlargement.

CSF sub-compartments in relation to plasma osmolality in healthy controls and in patients with first episode schizophrenia

Preliminary evidence suggests that plasma Na(+) level/osmolality may have effects on brain morphology; thus we investigated the link between plasma osmolality and ventricle size in healthy controls and patients with first episode schizophrenia. A total of 16 patients and 28 healthy controls were examined with magnetic resonance imaging (MRI) and gave blood samples. High-resolution 3D SPGR images were obtained on a 1.5 Tesla scanner. Scalp-edited MRI volumes were used for estimates of intracranial gray, white matter and CSF. Regional changes in CSF concentration and ventricular morphology were measured. The groups did not differ in plasma osmolality, but patients had higher plasma Na(+). There were no differences in ventricle size. Controlling for plasma osmolality did not change the results. A mixed model procedure indicated a significant group effect and a significant osmolality by group interaction in ventricle measures. Healthy control group showed a significant relationship between osmolality and ventricle measures; this relationship was absent in the patients. Significant correlations between osmolality and lateral ventricle surface deformations were observed along the superior horn of the lateral ventricles in the healthy controls. These results suggest that plasma osmolality is related to ventricle size in healthy volunteers and that this physiological link is impaired in patients with first episode schizophrenia.

Brainstem application of melanocortin receptor ligands produces long-lasting effects on feeding and body weight

Recent evidence suggests that the central melanocortin (MC) system is a prominent contributor to food intake and body weight control. MC receptor (MC-R) populations in the arcuate and paraventricular nuclei are considered probable sites of action mediating the orexigenic effects of systemically or intracerebroventricularly administered ligands. Yet, the highest MC4-R density in the brain is found in the dorsal motor nucleus of the vagus nerve, situated subjacent to the commissural nucleus of the solitary tract, a site of pro-opiomelanocortin mRNA expression. We evaluated the contribution of the caudal brainstem MC system by (1) performing respective dose-response analyses for an MC-R agonist (MTII) and antagonist (SHU9119) delivered to the fourth ventricle, (2) comparing, in the same rats, the fourth intracerebroventricular dose-response profiles to those obtained with lateral intracerebroventricular delivery, and (3) delivering an effective dose of MTII or SHU9119 to rats before a 24 hr period of food deprivation. Fourth intracerebroventricular agonist treatment yielded a dose-dependent reduction of short-term (2 and 4 hr) and longer-term (24 hr) food intake and body weight. Fourth intracerebroventricular antagonist treatment produced the opposite pattern of results: dose-related increases in food intake and corresponding increases in body weight change for the 24-96 hr observation period. Comparable dose-response functions for food intake and body weight were observed when these compounds were delivered to the lateral ventricle. Results from deprived rats (no effect of MTII or SHU9119 on weight loss) support the impression derived from the dose-response analyses that the body weight change that follows MC treatments is secondary to their respective effects on food intake. Results support the relevance of the brainstem MC-R complement to the control of feeding.