Variaciones de los plexos coroideos y las barreras cerebrales en la hipertensión arterial y el envejecimiento

IntroductionThe choroid plexuses, blood vessels, and brain barriers are closely related both in terms of morphology and function. Hypertension causes changes in cerebral blood flow and in small vessels and capillaries of the brain. This review studies the effects of high blood pressure (HBP) on the choroid plexuses and brain barriers.DevelopmentThe choroid plexuses (ChP) are structures located in the cerebral ventricles, and are highly conserved both phylogenetically and ontogenetically. The ChPs develop during embryogenesis, forming a functional barrier during the first weeks of gestation. They are composed of highly vascularised epithelial tissue covered by microvilli, and their main function is cerebrospinal fluid (CSF) production. The central nervous system (CNS) is protected by the blood-brain barrier (BBB) and the blood–CSF barrier (BCSFB). While the BBB is formed by endothelial cells of the microvasculature of the CNS, the BCSFB is formed by epithelial cells of the choroid plexuses. Chronic hypertension induces vascular remodelling. This prevents hyperperfusion at HBPs, but increases the risk of ischaemia at low blood pressures. In normotensive individuals, in contrast, cerebral circulation is self-regulated, blood flow remains constant, and the integrity of the BBB is preserved.ConclusionsHBP induces changes in the choroid plexuses that affect the stroma, blood vessels, and CSF production. HBP also exacerbates age-related ChP dysfunction and causes alterations in the brain barriers, which are more marked in the BCSFB than in the BBB. Brain barrier damage may be determined by quantifying blood S-100β and TTRm levels.     

Spontaneous and reflex movements after diagnosis of clinical brain death: A lesson from acute encephalopathy

BackgroundOrgan transplantation after brain death (BD) of the donor has been promoted in many countries as an established medical treatment. However, some problems with brain-dead organ transplantation have been reported. For example, there is no evidence as to the optimal observation period for a diagnosis and no evidence to support the interpretation of the various body movements observed after the determination of BD.Case reportA previously healthy 17-month-old girl with severe febrile convulsive status was transferred to our intensive care unit. The convulsions were refractory and the patient required respiratory management due to whole brain edema on head CT. Later she was diagnosed with acute encephalopathy. The patient showed a flat EEG, no responses on auditory brainstem responses (ABR), and loss of brainstem reflexes on repeated daily examinations. No apnea test was performed. Based on the diagnosis of clinical BD, coordinator of Japan Organ Transplant Network explained about organ donation on the 17th day of the disease. Subsequently, the family responded that they could not consent to organ donation, and the patient did not proceed to the legal BD determination. Around five weeks after the onset, spontaneous body movements began to appear, as not only the spinal reflexes but also the brainstem involvement.ConclusionThe pathophysiology of acute encephalopathy is largely unknown, and it is difficult to determine the observation period necessary for BD determination. What we have learned from this case is that clinical BD remains ambiguous and cannot be confirmed even with a thorough neurological examination, EEG, and ABR.     

Endovascular deep brain stimulation: Investigating the relationship between vascular structures and deep brain stimulation targets

BackgroundEndovascular delivery of current using ‘stentrodes’ – electrode bearing stents – constitutes a potential alternative to conventional deep brain stimulation (DBS). The precise neuroanatomical relationships between DBS targets and the vascular system, however, are poorly characterized to date.ObjectiveTo establish the relationships between cerebrovascular system and DBS targets and investigate the feasibility of endovascular stimulation as an alternative to DBS.MethodsNeuroanatomical targets as employed during deep brain stimulation (anterior limb of the internal capsule, dentatorubrothalamic tract, fornix, globus pallidus pars interna, medial forebrain bundle, nucleus accumbens, pedunculopontine nucleus, subcallosal cingulate cortex, subthalamic nucleus, and ventral intermediate nucleus) were superimposed onto probabilistic vascular atlases obtained from 42 healthy individuals. Euclidian distances between targets and associated vessels were measured. To determine the electrical currents necessary to encapsulate the predefined neurosurgical targets and identify potentially side-effect inducing substrates, a preliminary volume of tissue activated (VTA) analysis was performed.ResultsSix out of ten DBS targets were deemed suitable for endovascular stimulation: medial forebrain bundle (vascular site: P1 segment of posterior cerebral artery), nucleus accumbens (vascular site: A1 segment of anterior cerebral artery), dentatorubrothalamic tract (vascular site: s2 segment of superior cerebellar artery), fornix (vascular site: internal cerebral vein), pedunculopontine nucleus (vascular site: lateral mesencephalic vein), and subcallosal cingulate cortex (vascular site: A2 segment of anterior cerebral artery). While VTAs effectively encapsulated mfb and NA at current thresholds of 3.5 V and 4.5 V respectively, incremental amplitude increases were required to effectively cover fornix, PPN and SCC target (mean voltage: 8.2 ± 4.8 V, range: 3.0–17.0 V). The side-effect profile associated with endovascular stimulation seems to be comparable to conventional lead implantation. Tailoring of targets towards vascular sites, however, may allow to reduce adverse effects, while maintaining the efficacy of neural entrainment within the target tissue.ConclusionsWhile several challenges remain at present, endovascular stimulation of select DBS targets seems feasible offering novel and exciting opportunities in the neuromodulation armamentarium.     

Neuroendocrine,epigenetic, and intergenerational effects of general anesthetics

The progress of modern medicine would be impossible without the use of general anesthetics (GAs). Despite advancements in refining anesthesia approaches, the effects of GAs are not fully reversible upon GA withdrawal. Neurocognitive deficiencies attributed to GA exposure may persist in neonates or endure for weeks to years in the elderly. Human studies on the mechanisms of the long-term adverse effects of GAs are needed to improve the safety of general anesthesia but they are hampered not only by ethical limitations specific to human research, but also by a lack of specific biological markers that can be used in human studies to safely and objectively study such effects. The latter can primarily be attributed to an insufficient understanding of the full range of the biological effects induced by GAs and the molecular mechanisms mediating such effects even in rodents, which are far more extensively studied than any other species. Our most recent experimental findings in rodents suggest that GAs may adversely affect many more people than is currently anticipated. Specifically, we have shown that anesthesia with the commonly used GA sevoflurane induces in exposed animals not only neuroendocrine abnormalities (somatic effects), but also epigenetic reprogramming of germ cells (germ cell effects). The latter may pass the neurobehavioral effects of parental sevoflurane exposure to the offspring, who may be affected even at levels of anesthesia that are not harmful to the exposed parents. The large number of patients who require general anesthesia, the even larger number of their future unexposed offspring whose health may be affected, and a growing number of neurodevelopmental disorders of unknown etiology underscore the translational importance of investigating the intergenerational effects of GAs. In this mini review, we discuss emerging experimental findings on neuroendocrine, epigenetic, and intergenerational effects of GAs.     

Developmental trajectories of cortical thickness by functional brain network: The roles of pubertal timing and socioeconomic status

The human cerebral cortex undergoes considerable changes during development, with cortical maturation patterns reflecting regional heterogeneity that generally progresses in a posterior-to-anterior fashion. However, the organizing principles that govern cortical development remain unclear. In the current study, we characterized age-related differences in cortical thickness (CT) as a function of sex, pubertal timing, and two dissociable indices of socioeconomic status (i.e., income-to-needs and maternal education) in the context of functional brain network organization, using a cross-sectional sample (n = 789) diverse in race, ethnicity, and socioeconomic status from the Lifespan Human Connectome Project in Development (HCP-D). We found that CT generally followed a linear decline from 5 to 21 years of age, except for three functional networks that displayed nonlinear trajectories. We found no main effect of sex or age by sex interaction for any network. Earlier pubertal timing was associated with reduced mean CT and CT in seven networks. We also found a significant age by maternal education interaction for mean CT across cortex and CT in the dorsal attention network, where higher levels of maternal education were associated with steeper age-related decreases in CT. Taken together, our results suggest that these biological and environmental variations may impact the emerging functional connectome.     

Heparin Flush Use in Transfemoral Cerebral Angiography Survey

The drug concentration of heparinized saline used for transfemoral catheter angiography flush during different types of cerebral angiogram procedures varies among providers and centers worldwide. Although heparin is recommended for use during cerebral angiograms to minimize the risk of thromboembolic events associated with the utilization of multiple endovascular devices and lengthy procedures, there is a paucity of information available regarding protocols for administration of heparin and heparinized saline. Higher concentrations of heparinized saline flush may benefit patients undergoing elective nonruptured intracranial aneurysm embolization procedures by decreasing the risk of thromboembolism. However, it could potentially place patients undergoing revascularization procedures for acute ischemic stroke at higher risk of symptomatic intracerebral hemorrhage, particularly if they received intravenous tissue plasminogen activator immediately before endovascular thrombectomy. After obtaining permission from the Association for Radiologic and Imaging Nursing (ARIN) Board of Directors, a survey was presented in English and electronically distributed by the ARIN to all current and past ARIN members with valid e-mail addresses. The survey was preceded by an introductory letter explaining the study purpose and its voluntary nature. Response to the survey was identified as consent to participate. Subjects were asked to participate if they were currently involved in the management of patients undergoing cerebral angiography with a variety of interventions including management of acute ischemic and hemorrhagic stroke. There is a paucity of evidence supporting use of a specific concentration of heparinized saline solution. It ranges from no heparin added to concentrations exceeding 5 units/mL for transfemoral flush. The most frequently used concentration is 2 units/mL (32.8–34.8% of respondents depending on endovascular intervention), and the least frequently utilized concentrations are 3 units/mL and higher than 5 units/mL (4.3–5.7% of respondents depending on endovascular intervention). Mixing and labeling bags with heparinized saline flush was noted to be the responsibility of interventional radiology registered nurse (39%, n = 46), pharmacy (26.3%, n = 31), or the angiography technologist (8.5%, n = 10). More than quarter (26.5%) of respondents noted not having readily available premixed heparinized saline flush. Twenty-four (20.3%) of survey participants claimed using only premixed bags of heparinized saline solution. Despite the Institute for Healthcare Improvement, Institute for Safe Medication Practices and Joint Commission recommendations, there are no standard protocols across stroke centers identifying optimal heparinized saline flush solution concentration, preparation, and documentation. Replication of this survey among members of the American Society of Neuroradiology is recommended to validate the findings from the present study. If confirmed, a consensus on safety of heparinized saline flush use during neuroradiology interventions is strongly advised.     

康复护理干预在改善脑梗死后患者日常生活能力和认知功能中的应用效果

目的 探讨康复护理对脑梗死后认知功能障碍及日常生活能力的影响及意义。方法 将90 例脑梗死后发生认知功能障碍的患者依随机数字表法分为观察组(45例)与对照组(45例)。对照组和观察组均 实施常规的护理治疗措施,此外,对观察组实施早期的康复护理措施。 疗程为1个月,比较两组患者的认知功能障碍及日常生活能力的情况。结果 试验1个月后,观察组有效率为78%,对照组有效率为31%,两组的临床疗效差异有统计学意义(χ²=19.929,P＜0.001)。观察组的简易智能精神状态检查量表(MMSE)、韦氏成人记忆量表(WMS)和日常生活功能量表(ADL)评分明显增高,两组MMSE(t=3.226,P=0.002)、WMS(t=3.394,P=0.001)、ADL(t=7.221,P<0.001)得分均差异有统计学意义。结论 早期康复护理干预对脑梗死患者具有良好的临床疗效,可以显著改善患者认知功能及日常生活能力。     

Automated brain MRI metrics in the EPIRMEX cohort of preterm newborns: Correlation with the neurodevelopmental outcome at 2 years

PurposeThe purpose of this study was to identify in the EPIRMEX cohort the correlations between MRI brain metrics, including diffuse excessive high signal intensities (DEHSI) obtained with an automated quantitative method and neurodevelopmental outcomes at 2 years.Materials and methodsA total of 390 very preterm infants (gestational age at birth ≤ 32 weeks) who underwent brain MRI at term equivalent age at 1.5T (n = 338) or 3T (n = 52) were prospectively included. Using a validated algorithm, automated metrics of the main brain surfaces (cortical and deep gray matter, white matter, cerebrospinal fluid) and DEHSI with three thresholds were obtained. Linear adjust regressions were performed to assess the correlation between brain metrics with the ages and stages questionnaire (ASQ) score at 2 years.ResultsBasal ganglia and thalami, cortex and white matter surfaces positively and significantly correlated with the global ASQ score. For all ASQ sub-domains, basal ganglia and thalami surfaces significantly correlated with the scores. DEHSI was present in 289 premature newborns (74%) without any correlation with the ASQ score. Metrics of DEHSI were greater at 3T than at 1.5T.ConclusionBrain MRI metrics obtained in our multicentric cohort correlate with the neurodevelopmental outcome at 2 years of age. The quantitative detection of DEHSI is not predictive of adverse outcomes. Our automated algorithm might easily provide useful predictive information in daily practice.     

Prostate Cancer Central Nervous System Metastasis in a Contemporary Cohort

IntroductionCentral nervous system (CNS) metastasis from prostate cancer (PCA) is a rare event, but one with significant prognostic impact for those affected. There are limited data on its impact in contemporary cohorts treated with modern agents.Patients and MethodsA retrospective institutional review was performed to characterize the occurrence/outcome of PCA CNS metastasis on all cases of PCA from 2011 to 2017. A manual chart review was performed to confirm PCA CNS metastases in all cases identified through a diagnostic code screening of the health data.ResultsA total of 6596 cases of PCA were identified, with 29 (20 dural and 9 intraparenchymal) confirmed cases of CNS metastases from PCA. The median survival from the time of diagnosis of CNS metastasis was 2.6 months (95% confidence interval, 2.04-10.78 months) and 5.41 months (95% confidence interval, 3.03 months to not reached) for dural and parenchymal metastases, respectively. Among those who developed CNS metastases, approximately 79% of patients had prior exposure to abiraterone and/or enzalutamide, of whom 50% had ≥ 6 months of exposure. Four (0.07%) of the 5841 patients developed CNS metastases prior to the initiation of therapy or on androgen deprivation therapy alone. In contrast, 24 (8.6%) of the 279 patients with 2 or more lines of medical therapy developed CNS metastases.ConclusionsOur analysis highlights the continued poor prognosis of parenchymal and dural CNS metastases from PCA. CNS metastases in PCA remain a rare event with a 0.4% incidence in this series, but this incidence is considerably increased in patients who receive medical therapy beyond first-line androgen deprivation therapy.