Role of endogenous testosterone concentration in pediatric stroke

Prevalence & Risk Factors for Perinatal Stroke: A Population-Based Study

Objectives

The study objective was to calculate the birth prevalence of perinatal stroke and examine risk factors in term infants. Some risk factors are present in healthy infants, making it difficult to determine at-risk infants.

Study Design

Prospective population-based perinatal stroke data were compared to the Australian general population data using chi-squared and Fisher's exact tests and multivariable logistic regression analysis.

Results

Sixty perinatal stroke cases were reported between 2017 and 2019. Estimated stroke prevalence was 9.6/100,000 live births/year including 5.8 for neonatal arterial ischemic stroke and 2.9 for neonatal hemorrhagic stroke. Eighty seven percent had multiple risk factors. Significant risk factors were cesarean section (p = 0.04), 5-min Apgar score <7 (p < 0.01), neonatal resuscitation (p < 0.01) and nulliparity (p < 0.01).

Conclusions

Statistically significant independent risk factors do not fully explain the cause of perinatal stroke, because they are not a direct causal pathway to stroke. These data now require validation in a case-control study.

Research progress on the role of hormones in ischemic stroke

Ischemic stroke is a major cause of death and disability around the world. However, ischemic stroke treatment is currently limited, with a narrow therapeutic window and unsatisfactory post-treatment outcomes. Therefore, it is critical to investigate the pathophysiological mechanisms following ischemic stroke brain injury. Changes in the immunometabolism and endocrine system after ischemic stroke are important in understanding the pathophysiological mechanisms of cerebral ischemic injury. Hormones are biologically active substances produced by endocrine glands or endocrine cells that play an important role in the organism's growth, development, metabolism, reproduction, and aging. Hormone research in ischemic stroke has made very promising progress. Hormone levels fluctuate during an ischemic stroke. Hormones regulate neuronal plasticity, promote neurotrophic factor formation, reduce cell death, apoptosis, inflammation, excitotoxicity, oxidative and nitrative stress, and brain edema in ischemic stroke. In recent years, many studies have been done on the role of thyroid hormone, growth hormone, testosterone, prolactin, oxytocin, glucocorticoid, parathyroid hormone, and dopamine in ischemic stroke, but comprehensive reviews are scarce. This review focuses on the role of hormones in the pathophysiology of ischemic stroke and discusses the mechanisms involved, intending to provide a reference value for ischemic stroke treatment and prevention.

Childhood stroke

Stroke is an important cause of neurological morbidity in children; most survivors have permanent neurological deficits that affect the remainder of their life. Stroke in childhood, the focus of this Primer, is distinguished from perinatal stroke, defined as stroke before 29 days of age, because of its unique pathogenesis reflecting the maternal-fetal unit. Although approximately 15% of strokes in adults are haemorrhagic, half of incident strokes in children are haemorrhagic and half are ischaemic. The causes of childhood stroke are distinct from those in adults. Urgent brain imaging is essential to confirm the stroke diagnosis and guide decisions about hyperacute therapies. Secondary stroke prevention strongly depends on the underlying aetiology. While the past decade has seen substantial advances in paediatric stroke research, the quality of evidence for interventions, such as the rapid reperfusion therapies that have revolutionized arterial ischaemic stroke care in adults, remains low. Substantial time delays in diagnosis and treatment continue to challenge best possible care. Effective primary stroke prevention strategies in children with sickle cell disease represent a major success, yet barriers to implementation persist. The multidisciplinary members of the International Pediatric Stroke Organization are coordinating global efforts to tackle these challenges and improve the outcomes in children with cerebrovascular disease.

Venous Thromboembolism among Critically Ill Children: A Narrative Review

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality among hospitalized patients, including children. In recent years, it has become clear that hospitalization and critical illness bestow an increased VTE risk in pediatrics and relate to mortality and life-limiting comorbidities. For critically ill children, reported rates of VTE vary by study sampling techniques, presence of inherited or acquired thrombophilia, acute and chronic immobility, underlying illness prompting hospitalization, and clinical factors related to illness severity such as central venous catheterization, length of stay, mechanical ventilation, and patient age. Accordingly, critically ill children with new signs of venous congestion, acute inflammation, or unexplained acute organ dysfunction should be routinely evaluated for VTE. This narrative review summarizes recent and historical literature regarding risk factors, prevention, presentation, treatment, and outcomes of VTE in critically ill children. In addition, we identify knowledge gaps and priorities for future collaborative research on this vital condition. Special attention is given to the clinical trial opportunities, challenges, and ongoing efforts in thromboprophylaxis in critically ill children, including those hospitalized for disease related to novel coronavirus (COVID-19) and multisystem inflammatory disease in children.

The Impact of Sex on Arterial Ischemic Stroke in Young Patients: From Stroke Occurrence to Poststroke Consequences

The male sex has been suggested to predominate in paediatric patients with arterial ischemic stroke (AIS), especially in newborns. The explanation for this phenomenon remains unsatisfactory since it focuses on the analysis of the potential relationship with trauma and arterial dissection. In turn, in some populations of young adults, men suffer from AIS more frequently than women, which may be related to the protective role of oestrogen. On the other hand, certain data indicate that women dominate over men. Some of the disparities in the frequencies of particular symptoms of AIS and poststroke consequences in both children and young adults have been suggested; however, data are scarce. Unfortunately, the low number of studies on the subject does not allow certain conclusions to be drawn. For adults, more data are available for patients aged over 60 years, the results of which are more obvious. The present literature review aimed to discuss available data on the prevalence of AIS, its clinical presentations, and poststroke consequences in regard to the sex of young patients. We considered young patients to be children from birth up to the age of 19 years of life and young adults to be individuals up to the age of 55 years. The role of sex hormones in AIS and possible gender differences in genetic risk factors for AIS were also discussed briefly.

Increased P450 aromatase levels in post-menopausal women after acute ischemic stroke

Background

Sex differences in stroke have been attributed to the neuroprotective effects of estrogen, yet most clinical trials of estrogen supplementation for stroke prevention have failed. The contribution of sex hormones to stroke outcome remains a subject of debate. Aromatization of testosterone to estradiol in neural tissue leads to sexual differentiation. Emerging data suggests aromatase activity increases in response to brain injury, and increased aromatase expression is seen in the ischemic penumbra in animal models. The objective of this study was to examine the levels of endogenous sex steroids after acute ischemic stroke and determine if levels of sex steroids were associated with acute stroke outcomes.

Methods

Peripheral blood from ischemic stroke patients and controls was collected under an approved IRB within 24 h of symptom onset. 17β-estradiol, testosterone, and aromatase levels were measured in the serum of both men and women using ELISA. Hormone levels were compared in men vs. women in stroke and control groups and correlated with outcomes (NIHSS and change in the modified Rankin Scale (mRS), defined as the difference of premorbid and discharge mRS) using multivariate regression.

Results

We found no significant difference in estradiol levels 24 h after stroke in men (p = 0.86) or women (p = 0.10). In men, testosterone significantly decreased after stroke as compared with controls (1.83 ± 0.12 vs. 2.86 ± 0.65, p = 0.01). Aromatase levels were significantly increased in women after stroke as compared with controls (2.27 ± 0.22 vs. 0.97 ± 0.22, p = 0.002), but not in men (p = 0.84). Estradiol levels positively correlated with change in mRS in both women (r = 0.38, p = 0.02) and men (r = 0.3, p = 0.04).

Conclusions

Estradiol levels correlated with functional outcomes (change in mRS) in both men and women, at least in the acute phase (24 h) of stroke. However, no significant difference in estradiol levels is seen 24 h post-stroke in men or women. Testosterone levels decrease at 24 h after stroke in men. As seen in animal models, aromatase levels increase after acute ischemic stroke, but this was only true for women. These indicate an active aromatization process in post-menopausal women after acute ischemic stroke.

Androgens' effects on cerebrovascular function in health and disease

Androgens affect the cerebral vasculature and may contribute to sex differences in cerebrovascular diseases. Men are at a greater risk for stroke and vascular contributions to cognitive impairment and dementia (VCID) compared to women throughout much of the lifespan. The cerebral vasculature is a target for direct androgen actions, as it expresses several sex steroid receptors and metabolizing enzymes. Androgens’ actions on the cerebral vasculature are complex, as they have been shown to have both protective and detrimental effects, depending on factors such as age, dose, and disease state. When administered chronically, androgens are shown to be pro-angiogenic, promote vasoconstriction, and influence blood-brain barrier permeability. In addition to these direct effects of androgens on the cerebral vasculature, androgens also influence other vascular risk factors that may contribute to sex differences in cerebrovascular diseases. In men, low androgen levels have been linked to metabolic and cardiovascular diseases including hypertension, diabetes, hyperlipidemia, and obesity, which greatly increase the risk of stroke and VCID. Thus, a better understanding of androgens’ interactions with the cerebral vasculature under physiological and pathological conditions is of key importance.

Role of prothrombin 19911 A>G polymorphism, blood group and male gender in patients with venous thromboembolism: Results of a German cohort study

The role of the A>G polymorphism at position 19911 in the prothrombin gene (factor [F] 2 at rs3136516) as a risk factor for venous thromboembolism [VTE] is still unclear. To evaluate the presence of the F2 polymorphism in VTE patients compared to healthy blood donors and to adjust the results for common inherited thrombophilias [IT], age at onset and blood group [BG], and to calculate the risk of VTE recurrence. We investigated 1012 Caucasian patients with a diagnosis of VTE for the presence of the F2 rs3136516 polymorphism and compared these with 902 healthy blood donors. Odds ratios [OR] together with their 95% confidence intervals were calculated adjusted for F5 at rs6025, F2 at rs1799963, blood group, age and gender. In addition, we evaluated the risk of recurrent VTE during patient follow-up calculating hazard ratios [HR] together with their 95% CI. Compared with the AA wildtype, the F2 GG and AG genotypes (rs3136516) were associated with VTE (OR 1.48 and 1.45). The OR in F5 carriers compared to controls was 5.68 and 2.38 in patients with F2 (rs1799963). BG "non-O" was significantly more often diagnosed in patients compared to BG "O" (OR 2.74). VTE recurrence more often occurred in males (HR 2.3) and in carriers with combined thrombophilia (HR 2.11). Noteworthy, the rs3136516 polymorphism alone was not associated significantly with recurrence. In Caucasian patients with VTE the F2 GG/GA genotypes (rs3136516) were moderate risk factors for VTE. Recurrence was associated with male gender and combined thrombophilia.

Spectrum of cerebral arteriopathies in children with arterial ischemic stroke

OBJECTIVE

To determine that children with arterial ischemic stroke (AIS) due to an identifiable arteriopathy are distinct from those without arteriopathy and that each arteriopathy subtype has unique and recognizable clinical features.

METHODS

We report a large, observational, multicenter cohort of children with AIS, age 1 month to 18 years, enrolled in the International Pediatric Stroke Study from 2003 to 2014. Clinical and demographic differences were compared by use of the Fisher exact test, with linear step-up permutation min-p adjustment for multiple comparisons. Exploratory analyses were conducted to evaluate differences between cases of AIS with and without arteriopathy and between arteriopathy subtypes.

RESULTS

Of 2,127 children with AIS, 725 (34%) had arteriopathy (median age 7.45 years). Arteriopathy subtypes included dissection (27%), moyamoya (24.5%), focal cerebral arteriopathy-inflammatory subtype (FCA-i; 15%), diffuse cerebral vasculitis (15%), and nonspecific arteriopathy (18.5%). Children with arteriopathic AIS were more likely to present between 6 and 9 years of age (odds ratio [OR] 1.93, p = 0.029) with headache (OR 1.55, p = 0.023), multiple infarctions (OR 2.05, p < 0.001), sickle cell anemia (OR 2.9, p = 0.007), and head/neck trauma (OR 1.93, p = 0.018). Antithrombotic use and stroke recurrence were higher in children with arteriopathy. Among arteriopathy subtypes, dissection was associated with male sex, older age, headache, and anticoagulant use; FCA-i was associated with hemiparesis and single infarcts; moyamoya was associated with seizures and recurrent strokes; and vasculitis was associated with bilateral infarctions.

CONCLUSION

Specific clinical profiles are associated with cerebral arteriopathies in children with AIS. These observations may be helpful indicators in guiding early diagnosis and defining subgroups who may benefit most from future therapeutic trials.

Comparative study of posterior and anterior circulation stroke in childhood: Results from the International Pediatric Stroke Study

OBJECTIVE

To compare risk factors, clinical presentation, and outcomes after posterior circulation arterial ischemic stroke (PCAIS) and anterior circulation arterial ischemic stroke (ACAIS) in neonates and children.

METHODS

In this international multicenter observational study including neonates and children up to 18 years of age with arterial ischemic stroke (AIS), we compared clinical and radiologic features according to stroke location.

RESULTS

Of 2,768 AIS cases, 507 (18%) were located in the posterior circulation, 1,931 (70%) in the anterior circulation, and 330 (12%) involved both. PCAIS was less frequent in neonates compared to children (8.8% vs 22%, p < 0.001). Children with PCAIS were older than children with ACAIS (median age 7.8 [interquartile range (IQR) 3.1-14] vs 5.1 [IQR 1.5-12] years, p < 0.001), and more often presented with headache (54% vs 32%, p < 0.001) and a lower Pediatric NIH Stroke Scale score (4 [IQR 2-8] vs 8 [IQR 3-13], p = 0.001). Cervicocephalic artery dissections (CCAD) were more frequent (20% vs 8.5%, p < 0.001), while cardioembolic strokes were less frequent (19% vs 32%, p < 0.001) in PCAIS. Case fatality rates were equal in both groups (2.9%). PCAIS survivors had a better outcome (normal neurologic examination at hospital discharge in 29% vs 21%, p = 0.002) than ACAIS survivors, although this trend was only observed in children and not in neonates.

CONCLUSION

PCAIS is less common than ACAIS in both neonates and children. Children with PCAIS are older and have a higher rate of CCAD, lower clinical stroke severity, and better outcome than children with ACAIS.

A Mechanistic and Pathophysiological Approach for Stroke Associated with Drugs of Abuse

Drugs of abuse are associated with stroke, especially in young individuals. The major classes of drugs linked to stroke are cocaine, amphetamines, heroin, morphine, cannabis, and new synthetic cannabinoids, along with androgenic anabolic steroids (AASs). Both ischemic and hemorrhagic stroke have been reported due to drug abuse. Several common mechanisms have been identified, such as arrhythmias and cardioembolism, hypoxia, vascular toxicity, vascular spasm and effects on the thrombotic mechanism, as causes for ischemic stroke. For hemorrhagic stroke, acute hypertension, aneurysm formation/rupture and angiitis-like changes have been implicated. In AAS abuse, the effect of blood pressure is rather substance specific, whereas increased erythropoiesis usually leads to thromboembolism. Transient vasospasm, caused by synthetic cannabinoids, could lead to ischemic stroke. Opiates often cause infective endocarditis, resulting in ischemic stroke and hypereosinophilia accompanied by pyogenic arthritis, provoking hemorrhagic stroke. Genetic variants are linked to increased risk for stroke in cocaine abuse. The fact that case reports on cannabis-induced stroke usually refer to the young population is very alarming.

Stroke in Pediatric Bacterial Meningitis: Population-Based Epidemiology

BACKGROUND

Bacterial meningitis is a severe infection of the nervous system with a high complication rate including stroke. The purpose of this study is to assess the incidence, risk factors, patterns, and outcomes in pediatric meningitis complicated by stroke.

METHODS

The study design was a population-based, 10-year retrospective (2002 to 2012) cohort study set in Southern Alberta, Canada. The inclusion criteria were: (1) age from newborn to 18 years, (2) brain magnetic resonance imaging (MRI) including diffusion-weighted imaging during admission, and (3) laboratory confirmed acute bacterial meningitis. The main outcomes were demographics, clinical presentations, risk factors, laboratory findings, radiographic findings, and neurological outcomes.

FINDINGS

Forty-three patients had confirmed bacterial meningitis and diffusion MRI (9 neonates (21%), 89% male; 22 infants aged one month to one year (51%), 50% male; and 12 children older than one year (28%), 58% male, median age four years (interquartile range 7.9 years). Ischemic stroke was confirmed in 16/43 (37%), often multifocal (94%). Patients with stroke were significantly more likely to have seizures (P = 0.025), otitis media (P = 0.029), and multiple presentations to hospital (P = 0.013). Mortality was 25% in children with stroke compared with 4% in those without (P = 0.067). Survivors with stroke were more likely to have neurological deficits at follow-up (69% versus 26%, P = 0.019).

CONCLUSIONS

More than one-third of children with acute bacterial meningitis and clinically indicated MRI had ischemic stroke. Stroke was associated with clinical factors including duration of illness, seizures, and causative organisms. Stroke was associated with higher mortality and morbidity, warranting consideration of increased MRI screening and new approaches to treatment.

Post-stroke neovascularization and functional outcomes differ in diabetes depending on severity of injury and sex: Potential link to hemorrhagic transformation

Diabetes is associated with increased risk and worsened outcome of stroke. Previous studies showed that male diabetic animals had greater hemorrhagic transformation (HT), profound loss of cerebral vasculature, and poor behavioral outcomes after ischemic stroke induced by suture or embolic middle cerebral artery occlusion (MCAO). Females are protected from stroke until reaching the menopause age, but young females with diabetes have a higher risk of stroke and women account for the majority of stroke mortality. The current study postulated that diabetes is associated with greater vascular injury and exacerbated sensorimotor and cognitive outcome after stroke even in young female animals. Male and female control and diabetic animals were subjected to transient MCAO and followed for 3 or 14 days to assess the neurovascular injury and repair. The vascularization indices after stroke were lower in male diabetic animals with 90-min but not 60-min ischemia/reperfusion injury, while there was no change in female groups. Cognitive deficits were exacerbated in both male and female groups regardless of the injury period, while the sensorimotor dysfunction was worsened in male diabetic animals with longer ischemia time. These results suggest that diabetes negates the protection afforded by sex in young female animals, and post-stroke vascularization pattern is influenced by the degree of injury and correlates with functional outcome in both sexes. Vasculoprotection after acute ischemic stroke may provide a novel therapeutic strategy in diabetes.

Elucidating sex differences in response to cerebral ischemia: immunoregulatory mechanisms and the role of microRNAs

Cerebral ischemia remains a major cause of death and disability worldwide, yet therapeutic options remain limited. Differences in sex and age play an important role in the final outcome in response to cerebral ischemia in both experimental and clinical studies: males have a higher risk and worse outcome than females at younger ages and this trend reverses in older ages. Although the molecular mechanisms underlying sex dimorphism are complex and are still not well understood, studies suggest steroid hormones, sex chromosomes, differential cell death and immune pathways, and sex-specific microRNAs may contribute to the outcome following cerebral ischemia. This review focuses on differential effects between males and females on cell death and immunological pathways in response to cerebral ischemia, the central role of innate sex differences in steroid hormone signaling, and upstreamregulation of sexually dimorphic gene expression by microRNAs.

Risk Factors for Perinatal Arterial Ischemic Stroke: A Case-Control Study

Introduction

Arterial ischemic stroke in newborns is an important cause of neonatal morbidity and mortality. Its pathophysiology and associated risk factors are not yet clearly understood and defined.

Objective

The aim of this retrospective study was to investigate possible risk factors in diagnosed cases of PAIS (perinatal arterial ischemic stroke).

Materials and methods

Case-control study. Clinical data of patients with PAIS diagnosis were analyzed. Two healthy controls were selected for each PAIS case, matched for gestational age. Risk factors were explored using univariable and multivariable analysis.

Outcome

40 patients were included in the study, 24 males and 16 females; 52.5% of cases were diagnosed within the first month of birth, and 47.5% were retrospectively diagnosed. The results showed a male predominance (66.7%). The distribution of cerebral ischemic injury was predominantly medial cerebral artery (87.5%) and occurred more commonly in the left cerebral hemisphere (62.5%). Significant risk factors in the univariate analysis (P < 0.05) were primiparity, stillbirth, neonatal sepsis, asphyxia, twin pregnancy, placenta abruption, emergency cesarean section, Apgar score ≤7 after 5 min, breech presentation, and hyperbilirubinemia. In the multivariate analysis, primiparity (OR 11.74; CI 3.28-42.02), emergency cesarean section (OR 13.79; CI 3.51-54.13), birth asphyxia (OR 40.55; CI 3.08-532.94) and Apgar score ≤7 after 5 min (OR 13.75; CI 1.03-364.03) were significantly associated factors with PAIS. Only five (16.6%) patients had an abnormal thrombophilia study.

Conclusion

Risk factors of primiparity, emergency cesarean section, birth asphyxia, and Apgar score ≤7 after 5 min were significantly associated with perinatal stroke. More studies with a larger number of patients and with prolonged follow up are required to establish more clearly the associated risk factors involved in this pathology.

Risk factors in childhood arterial ischaemic stroke: Findings from a population-based study in Germany

OBJECTIVE

Acute treatment of childhood arterial ischaemic stroke and prevention strategies for recurrent stroke episodes depend strongly on each child's individual risk profile. The aim of this study is to characterize risk factors for childhood stroke, their occurrence in isolation or combination, and to identify possible common risk factor patterns.

METHODS

This population-based study was conducted via ESPED, a surveillance unit for rare paediatric diseases in Germany. Children aged >28days and <18 years with an acute arterial ischaemic stroke occurring between January 2015 and December 2016 were included.

RESULTS

Among 99 reported children with arterial ischaemic stroke, 56 children were male. Male predominance was significant in adolescents from 12 years old onward. Arterial ischaemic stroke was more common in very young children <2 years of age and in adolescence. No risk factor was identified in 27 children. Hypercoagulable states (29%), cardiac disorders (24%), and arteriopathies (21%) were the most common risk factors. Some risk factor categories were more likely to be identified in isolation (i.e. cardiac disorders, prothrombotic abnormalities and chronic head and neck disorders) than others. The number of risk factors (n = 0-4) per patient and risk factor categories did not differ by age.

CONCLUSION

Although we could not identify common patterns of risk factor combinations, several risk factors occurred more likely in isolation than others. Further research should focus on the impact of isolated presumed childhood stroke risk factors like certain prothrombotic abnormalities, migraine or a patent foramen ovale. With regard to different age groups, stroke mechanisms in male adolescents require particular attention.

Thrombophilia testing in children: What and when should be tested?

Venous thrombosis (VTE) in children is gaining increased awareness and apart from underlying medical conditions, recently reported systematic reviews on pediatric VTE (70% provoked) have shown significant associations between thrombosis and presence of inherited thrombophilic risk factors (IT), such as protein C-, protein S- and antithrombin deficiency, mutations of factor 5 (F5: rs6025) and factor 2 (F2: rs1799963), even more pronounced when combined IT were involved. Although we have learned more about the pathophysiology of VTE with the increased discovery of IT evidence is still lacking as to whether IT influence the clinical outcome in pediatric VTE. It still remains controversial as to whether children with VTE or offspring from thrombosis-prone families benefit from IT screening. Thus, IT testing in children should be individualized. If the decision "pro screening" is discussed as an appropriate option in adolescents with unprovoked VTE and in children with a positive family history for VTE screening should be performed in a specialized coagulation unit for acquired or inherited and prothrombotic defects based on the individual population background. Apart from the laboratory assessment for the presence/absence of lupus anticoagulants and antiphospholipid antibodies screening should be performed beyond the acute VTE onset and after withdrawal of anticoagulant medication possibly influencing laboratory results.

Microglia and Neonatal Brain Injury

Microglial cells are now recognized as the "gate-keepers" of healthy brain microenvironment with their disrupted functions adversely affecting neurovascular integrity, neuronal homeostasis, and network connectivity. The perception that these cells are purely toxic under neurodegenerative conditions has been challenged by a continuously increasing understanding of their complexity, the existence of a broad array of microglial phenotypes, and their ability to rapidly change in a context-dependent manner to attenuate or exacerbate injuries of different nature. Recent studies have demonstrated that microglial cells exert crucial physiological functions during embryonic and postnatal brain development, some of these functions being unique to particular stages of development, and extending far beyond sensing dangerous signals and serving as antigen presenting cells. In this focused review we cover the roles of microglial cells in regulating embryonic vasculogenesis, neurogenesis, and establishing network connectivity during postnatal brain development. We further discuss context-dependent microglial contribution to neonatal brain injuries associated with prenatal and postnatal infection and inflammation, in relation to neurodevelopmental disorders, as well as perinatal hypoxia-ischemia and arterial focal stroke. We also emphasize microglial phenotypic diversity, notably at the ultrastructural level, and their sex-dependent influence on the pathophysiology of neurodevelopmental disorders.

A Pediatric Case of Reversible Cerebral Vasoconstriction Syndrome With Similar Radiographic Findings to Posterior Reversible Encephalopathy Syndrome

BACKGROUND

Reversible cerebral vasoconstriction syndrome occurs predominantly in middle-aged women. Only nine pediatric patients with this syndrome have been reported.

PATIENT DESCRIPTION

We present a ten-year-old boy with reversible cerebral vasoconstriction syndrome with radiographic findings similar to those of posterior reversible encephalopathy syndrome (PRES). He presented with a thunderclap headache without a neurological deficit. Brain magnetic resonance angiography (MRA) revealed multifocal narrowing of the cerebral arteries, whereas magnetic resonance imaging (MRI) with diffusion-weighted imaging and fluid-attenuated inversion recovery demonstrated hyperintense lesions in the occipital lobes and the left cerebellum. The patient's symptoms resolved spontaneously after a few hours with no recurrence. MRA on the second day showed a complete normalization of the affected arteries, and MRI after one month demonstrated improvement in the abnormal findings, leading to a diagnosis of RCVS with radiographic findings similar to those of PRES.

CONCLUSIONS

This child's findings suggests that, RCVS, with or without PRES, may occur in children who present with a thunderclap headache.

Epidemiology and Outcomes of Arterial Ischemic Stroke in Children: The Canadian Pediatric Ischemic Stroke Registry

BACKGROUND

Pediatric arterial ischemic stroke remains incompletely understood. Population-based epidemiological data inform clinical trial design but are scant in this condition. We aimed to determine age-specific epidemiological characteristics of arterial ischemic stroke in neonates (birth to 28 days) and older children (29 days to 18 years).

METHODS

We conducted a 16-year, prospective, national population-based study, the Canadian Pediatric Ischemic Stroke Registry, across all 16 Canadian acute care children's hospitals. We prospectively enrolled children with arterial ischemic stroke from January 1992 to December 2001 and documented disease incidence, presentations, risk factors, and treatments. Study outcomes were assessed throughout 2008, including abnormal clinical outcomes (stroke-related death or neurological deficit) and recurrent arterial ischemic stroke or transient ischemic attack.

RESULTS

Among 1129 children enrolled with arterial ischemic stroke, stroke incidence was 1.72/100,000/year, (neonates 10.2/100,000 live births). Detailed clinical and radiological information were available for 933 children (232 neonates and 701 older children, 55% male). The predominant clinical presentations were seizures in neonates (88%), focal deficits in older children (77%), and diffuse neurological signs (54%) in both. Among neonates, 44% had no discernible risk factors. In older children, arteriopathy (49% of patients with vascular imaging), cardiac disorders (28%), and prothrombotic disorders (35% of patients tested) predominated. Antithrombotic treatment increased during the study period (P < 0.001). Stroke-specific mortality was 5%. Outcomes included neurological deficits in 60% of neonates and 70% of older children. Among neonates, deficits emerged during follow-up in 39%. Overall, an initially decreased level of consciousness, a nonspecific systemic presentation, and the presence of stroke risk factors predicted abnormal outcomes. For neonates, predictors were decreased level of consciousness, nonspecific systemic presentation, and basal ganglia infarcts. For older children, predictors were initial seizures, nonspecific systemic presentation, risk factors, and lack of antithrombotic treatment. Recurrent arterial ischemic stroke or transient ischemic attack developed in 12% of older children and was predicted by arteriopathy, presentation without seizures, and lack of antithrombotic treatment. Emerging deficit was predicted by neonatal age at stroke and by cardiac disease.

CONCLUSIONS

This national data set provides a population-based disease incidence rate and demonstrates the protective effect of antithrombotic treatment in older children, and frequent long-term emerging deficits in neonates and in children with cardiac disorders. Further clinical trials are required to develop effective age-appropriate treatments for children with acute arterial ischemic stroke.

Abnormal neurodevelopmental outcomes are very likely in cases of bilateral neonatal arterial ischaemic stroke

AIM

Neonatal arterial ischaemic stroke (AIS) is an important cause of severe neurological disability. This study aimed to analyse the clinical manifestations and outcomes of AIS patients.

METHODS

We enrolled neonates with AIS admitted to Severance Children's Hospital and Gangnam Severance Hospital between 2008 and 2015. AIS was confirmed using magnetic resonance imaging (MRI). We retrospectively reviewed the clinical manifestations, MRI findings, electroencephalography (EEG) findings and neurodevelopmental outcomes.

RESULTS

The study comprised 29 neonates (18 boys). The mean follow-up period was 15.4 months (range 6-44 months), and the mean age at diagnosis was 8.1 days. Seizure was the most common symptom (66%). Bilateral involvement was more common than unilateral involvement (52%). The middle cerebral artery was the most commonly identified territory (79%). Abnormal EEG findings were noted in 93% of the cases. Neurodevelopment was normal in 11 (38%) patients, while cerebral palsy and delayed development were noted in eight (28%) and six (21%) patients, respectively. Patients with bilateral involvement were very likely to have abnormal neurodevelopmental outcomes.

CONCLUSION

Our study showed that abnormal neurodevelopmental outcomes were very likely after cases of neonatal AIS with bilateral involvement, and clinicians should consider early and more effective interventions in such cases.

Genetic deletion of galectin-3 enhances neuroinflammation, affects microglial activation and contributes to sub-chronic injury in experimental neonatal focal stroke

The pathophysiology of neonatal stroke and adult stroke are distinct in many aspects, including the inflammatory response. We previously showed endogenously protective functions of microglial cells in acute neonatal stroke. We asked if galectin-3 (Gal3), a pleotropic molecule that mediates interactions between microglia/macrophages and the extracellular matrix (ECM), plays a role in early injury after transient middle cerebral occlusion (tMCAO) in postnatal day 9-10 mice. Compared to wild type (WT) pups, in Gal3 knockout pups injury was worse and cytokine/chemokine production altered, including further increase of MIP1α and MIP1β levels and reduced IL6 levels 72h after tMCAO. Lack of Gal3 did not affect morphological transformation or proliferation of microglia but markedly attenuated accumulation of CD11b⁺/CD45^med-high cells after injury, as determined by multi-color flow cytometry. tMCAO increased expression of αV and β₃ integrin subunits in CD11b⁺/CD45^low microglial cells and cells of non-monocyte lineage (CD11b^-/CD45^-), but not in CD11b⁺/CD45^med-high cells within injured regions of WT mice or Gal3-/- mice. αV upregulated in areas occupied and not occupied by CD68⁺ cells, most prominently in the ECM, lining blood vessels, with expanded αV coverage in Gal3-/- mice. Cumulatively, these data show that lack of Gal3 worsens subchronic injury after neonatal focal stroke, likely by altering the neuroinflammatory milieu, including an imbalance between pro- and anti-inflammatory molecules, effects on microglial activation, and deregulation of the composition of the ECM.

Risk factors for symptomatic venous and arterial thromboembolism in newborns, children and adolescents - What did we learn within the last 20years?

Venous thrombosis (VTE) in children is increasingly diagnosed, as advanced medical care has increased treatment intensity of hospitalized pediatric patients. The aim of this review was to summarize the data available and to discuss the controversial issue of thrombophilia screening in the light of the pediatric data available. Follow-up data for VTE recurrence in children suggest a recurrence rate between 3% (neonates) and 21% in individuals with unprovoked VTE. Apart from underlying medical conditions, recently reported systematic reviews on pediatric VTE (70% provoked) have shown significant associations between thrombosis and presence of protein C-, protein S- and antithrombin deficiency, factor 5 (F5: rs6025), factor 2 (F2: rs1799963), even more pronounced when combined inherited thrombophilias [IT] were involved. The F2 mutation, protein C-, protein S-, and antithrombin deficiency did also play a significant role at VTE recurrence. Although we have learned more about the pathophysiology of VTE with the increased discovery of IT evidence is still lacking as to whether IT influence the clinical outcome in pediatric VTE. It still remains controversial as to whether children with VTE or offspring from thrombosis-prone families benefit from IT screening. Thus, IT testing in children should be individualized.

[Reversible cerebral vasoconstriction syndrome: A rare pediatric cause of thunderclap headaches]

Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by thunderclap headaches with diffuse segmental constriction of cerebral arteries that resolves spontaneously within 3 months. We report on a case of a 13-year-old boy presenting with acute severe headaches, triggered by physical exertion. His past medical history was uneventful. Moderate headache persisted between exacerbations for 4 weeks. He secondarily presented with signs of intracranial hypertension. Brain magnetic resonance angiography (MRA) revealed multifocal narrowing of the cerebral arteries. A glucocorticoid treatment was started based on the hypothesis of primary angiitis of the CNS. The symptoms rapidly improved, and repeat angiography at 3 months showed no vasoconstriction. Although pediatric cases are rare, RCVS should be considered in a child complaining of severe headache, especially after the use of vasoactive drugs or after Valsalva manoeuvres. RCVS is attributed to a transient, reversible dysregulation of cerebral vascular tone, which leads to multifocal arterial constriction and dilation. Physical examination, laboratory values, and initial cranial computed tomography are unremarkable, except when RCVS is associated with complications. Thunderclap headaches tend to resolve and then recur over a 1- to 4-week period, often with a milder baseline headache persisting between acute exacerbations. Angiography shows segmental narrowing and dilatation of one or more arteries, like a string of beads. Despite the absence of a proven treatment, important steps should be taken during the acute phase: removal of precipitants such as vasoactive substances, giving the patient rest, lowering blood pressure, and controlling seizures. Drugs targeted at vasospasms, such as calcium channel inhibitors, can be considered when cerebral vasoconstriction has been assessed. In most patients, the RCVS symptoms resolve spontaneously within days or weeks. Ischemic and hemorrhagic stroke are the major complications of the syndrome. A diagnosis of RCVS can only be confirmed when the reversibility of the vasoconstriction is assessed.

Androgen receptor (AR) in cardiovascular diseases

Cardiovascular diseases (CVDs) are still the highest leading cause of death worldwide. Several risk factors have been linked to CVDs, including smoking, diabetes, hyperlipidemia, and gender among others. Sex hormones, especially the androgen and its receptor, androgen receptor (AR), have been linked to many diseases with a clear gender difference. Here, we summarize the effects of androgen/AR on CVDs, including hypertension, stroke, atherosclerosis, abdominal aortic aneurysm (AAA), myocardial hypertrophy, and heart failure, as well as the metabolic syndrome/diabetes and their impacts on CVDs. Androgen/AR signaling exacerbates hypertension, and anti-androgens may suppress hypertension. Androgen/AR signaling plays dual roles in strokes, depending on different kinds of factors; however, generally males have a higher incidence of strokes than females. Androgen and AR differentially modulate atherosclerosis. Androgen deficiency causes elevated lipid accumulation to enhance atherosclerosis; however, targeting AR in selective cells without altering serum androgen levels would suppress atherosclerosis progression. Androgen/AR signaling is crucial in AAA development and progression, and targeting androgen/AR profoundly restricts AAA progression. Men have increased cardiac hypertrophy compared with age-matched women that may be due to androgens. Finally, androgen/AR plays important roles in contributing to obesity and insulin/leptin resistance to increase the metabolic syndrome.

Radiological and clinical features of cerebral sinovenous thrombosis in newborns and older children

BACKGROUND AND PURPOSE

Cerebral sinovenous thrombosis (CSVT) represents an increasingly recognized cause of pediatric stroke. Our purpose was to assess gender and age differences in the etiology, clinical presentation, and imaging features of CSVT in neonates and older children.

METHODS

Subjects aged newborn to 18 years diagnosed with CSVT at the Lille university hospital between 2011 and 2014 were included.

RESULTS

Eleven neonates and 16 non-neonates constituted the study population. The incidence of CSVT was significantly higher in male newborns. Clinical presentation did not vary significantly between the groups. Risk factors were age-dependent, with acute systemic illnesses significantly predominating in neonates (54%), whereas local infections, prothrombotic conditions, and trauma were more common in older children (36, 27, and 27% respectively). No predisposing factor could be identified in 36% of the neonates as compared to less than 5% of the non-neonates. Thrombosis of the deep venous structures was documented in 73% of the neonates whereas involvement of the superficial sinuses was significantly more frequent in the non-neonates group. Venous infarctions and extraparenchymal hemorrhages were significantly more frequent in the neonates group.

CONCLUSION

Male patients are at higher risk for CSVT than females. In neonates, involvement of the deep venous structures is significantly more common. Brain parenchymal and extraparenchymal changes occur more frequently in this age group than in older children.

Prognosis of Neonatal Arterial Ischemic Stroke

Investigators from University Children's Hospitals in Bern, Zurich, Aarau, and multiple other centers in Switzerland evaluated prospectively the epidemiology, manifestations, and treatment of all full-term neonates with neonatal arterial ischemic stroke (NAIS) and born 2000-2010.

Serum Hepcidin Levels in Childhood-Onset Ischemic Stroke: A Case-Control Study

Recently, hepcidin, an antimicrobial-like peptide hormone, has evolved as the master regulator of iron homeostasis. Despite the growing evidence of iron imbalance in childhood-onset ischemic stroke, serum hepcidin level in those patients has not yet been researched. In this study, we aimed to estimate serum (hepcidin) level in acute ischemic stroke (AIS) patients and to investigate whether subcutaneous enoxaparin sodium, which is a low-molecular-weight heparin (LMWH) derivative, could modulate serum hepcidin level in those patients. This was a case-control study included 60 (AIS) cases, and 100 healthy children with comparable age and gender as control group. For all subjects' serum hepcidin, interleukin-6 (IL-6), and soluble transferrin receptor [sTfR]) levels were assessed by (enzyme-linked immunosorbent assay [ELISA] method). Iron parameters including (serum iron, ferritin, transferrin, and total iron binding capacity [TIBC]) were also measured. The patients were subdivided according to treatment with an LMWH derivative into 2 groups and serum hepcidin levels were assessed initially and 1 week after stroke onset for all cases. We found that AIS cases had higher serum iron, ferritin, and IL6 levels compared to the control group (all P < 0.01). Serum hepcidin was significantly higher in AIS cases (median, 36[15-73]ng/mL) compared to the control group (median, 24[10-41]ng/mL; P < 0.01). On the 1st day of AIS diagnosis, serum hepcidin levels were similar in both stroke subgroups (P > 0.05). However, on the 7th day of diagnosis serum hepcidin level decreased significantly in AIS cases treated with LMWH (group 1) (median, 36 vs 21 ng/mL; P < 0.01, respectively). Meanwhile, no significant change was observed in serum hepcidin level in AIS cases not treated with LMWH (group 2) (P > 0.05). Serum hepcidin showed significant positive correlations with serum iron, transferrin saturation, ferritin, and IL6 (r = 0.375, P < 0.05; r = 0.453, P < 0.05; r = 0.687, P < 0.01; r = 0.515, P < 0.01; respectively). Our data brought a novel observation of elevated serum hepcidin level in pediatric AIS patients and pointed out that treatment with LMWH could modulate hepcidin level in those patients.

Incidence and outcomes of symptomatic neonatal arterial ischemic stroke

BACKGROUND AND OBJECTIVES

Neonatal arterial ischemic stroke (NAIS) is associated with considerable lifetime burdens such as cerebral palsy, epilepsy, and cognitive impairment. Prospective epidemiologic studies that include outcome assessments are scarce. This study aimed to provide information on the epidemiology, clinical manifestations, infarct characteristics, associated clinical variables, treatment strategies, and outcomes of NAIS in a prospective, population-based cohort of Swiss children.

METHODS

This prospective study evaluated the epidemiology, clinical manifestations, vascular territories, associated clinical variables, and treatment of all full-term neonates diagnosed with NAIS and born in Switzerland between 2000 and 2010. Follow-up was performed 2 years (mean 23.3 months, SD 4.3 months) after birth.

RESULTS

One hundred neonates (67 boys) had a diagnosis of NAIS. The NAIS incidence in Switzerland during this time was 13 (95% confidence interval [CI], 11-17) per 100,000 live births. Seizures were the most common symptom (95%). Eighty-one percent had unilateral (80% left-sided) and 19% had bilateral lesions. Risk factors included maternal risk conditions (32%), birth complications (68%), and neonatal comorbidities (54%). Antithrombotic and antiplatelet therapy use was low (17%). No serious side effects were reported. Two years after birth, 39% were diagnosed with cerebral palsy and 31% had delayed mental performance.

CONCLUSIONS

NAIS in Switzerland shows a similar incidence as other population-based studies. About one-third of patients developed cerebral palsy or showed delayed mental performance 2 years after birth, and children with normal mental performance may still develop deficits later in life.

Paediatric cerebral sinovenous thrombosis: findings of the International Paediatric Stroke Study

OBJECTIVES

We evaluated clinical features, treatment practices and early outcome in a multicentre cohort of children with cerebral sinovenous thrombosis (CSVT).

METHODS

Children with CSVT from 10 countries were enrolled from January 2003 to July 2007 in the International Paediatric Stroke Study. We analysed clinical symptoms, underlying conditions, antithrombotic treatment and neurological outcome at hospital discharge in 170 children.

RESULTS

Of 170 children enrolled, 60% were male; median age 7.2 years (IQR 2.9-12.4). Headache, altered consciousness, focal deficits and seizures were common presenting clinical features. Infarction affected 37% and intracranial haemorrhage 31%. Risk factors included chronic disease in 50%; acute systemic illness or head/neck disorders 41%; prothrombotic state 20% and other haematological abnormality 19%. Discharge neurological status was normal in 48%, abnormal in 43% and unknown in 5%. Antithrombotic therapy was common, most often low molecular weight heparin was common, with significant regional variation in treatment practices. Mortality was low (4%) and was associated with no anticoagulation but not underlying chronic disease, anatomic extent of thrombosis or intracranial haemorrhage. Abnormal neurological status at discharge or death was associated with decreased level of consciousness at presentation and the presence of an identified prothrombotic state.

CONCLUSIONS

Our study extends the observations of previously published smaller studies in children with CSVT that this is a morbid disease with diverse underlying causes and risk factors. Divergent treatment practices among highly specialised centres as well as limited data on treatment efficacy and safety suggest that further study of this condition is warranted.

Stem cell therapy for neonatal hypoxic-ischemic encephalopathy

Treatments for neonatal hypoxic-ischemic encephalopathy (HIE) have been limited. The aim of this paper is to offer translational research guidance on stem cell therapy for neonatal HIE by examining clinically relevant animal models, practical stem cell sources, safety and efficacy of endpoint assays, as well as a general understanding of modes of action of this cellular therapy. In order to do so, we discuss the clinical manifestations of HIE, highlighting its overlapping pathologies with stroke and providing insights on the potential of cell therapy currently investigated in stroke, for HIE. To this end, we draw guidance from recommendations outlined in stem cell therapeutics as an emerging paradigm for stroke or STEPS, which have been recently modified to Baby STEPS to cater for the “neonatal” symptoms of HIE. These guidelines recognized that neonatal HIE exhibit distinct disease symptoms from adult stroke in need of an innovative translational approach that facilitates the entry of cell therapy in the clinic. Finally, new information about recent clinical trials and insights into combination therapy are provided with the vision that stem cell therapy may benefit from available treatments, such as hypothermia, already being tested in children diagnosed with HIE.

Mechanisms of perinatal arterial ischemic stroke

The incidence of perinatal stroke is high, similar to that in the elderly, and produces a significant morbidity and severe long-term neurologic and cognitive deficits, including cerebral palsy, epilepsy, neuropsychological impairments, and behavioral disorders. Emerging clinical data and data from experimental models of cerebral ischemia in neonatal rodents have shown that the pathophysiology of perinatal brain damage is multifactorial. These studies have revealed that, far from just being a smaller version of the adult brain, the neonatal brain is unique with a very particular and age-dependent responsiveness to hypoxia-ischemia and focal arterial stroke. In this review, we discuss fundamental clinical aspects of perinatal stroke as well as some of the most recent and relevant findings regarding the susceptibility of specific brain cell populations to injury, the dynamics and the mechanisms of neuronal cell death in injured neonates, the responses of neonatal blood-brain barrier to stroke in relation to systemic and local inflammation, and the long-term effects of stroke on angiogenesis and neurogenesis. Finally, we address translational strategies currently being considered for neonatal stroke as well as treatments that might effectively enhance repair later after injury.

Reparative effects of neural stem cells in neonatal rats with hypoxic-ischemic injury are not influenced by host sex

BACKGROUND

Gender is increasingly recognized as an important influence on brain development, disease susceptibility, and response to pharmacologic/rehabilitative treatments. In regenerative medicine, it remains entirely unknown whether there is an interaction between transplanted stem cells and host gender that might bias efficacy and safety in some patients but not others.

METHODS

We examined the role of recipient gender in a neonatal rat hypoxic-ischemic injury (HII) model, treated with female human neuronal stem cells (hNSCs), labeled with superparamagnetic iron oxide particles implanted into the contralateral cerebral ventricle. We monitored HII evolution (by magnetic resonance imaging, histopathology, behavioral testing) and hNSC fate (migration, replication, viability).

RESULTS

Recipient gender after implantation did not influence the volume or location of ischemic injury (1, 30, or 90 d) or behavior (90 d). Superparamagnetic iron oxide labeling did not influence HII evolution. Implantation had its greatest benefit on mild/moderate injuries, which remained stable rather than increasing as in severe HII as is the natural history for such lesions.

CONCLUSION

Our results suggest that hNSC treatment (including using hNSCs that are prelabeled with iron to allow tracking in real time by magnetic resonance imaging) would be equally safe and effective for male and female human newborns with mild-to-moderate HII.

Antiphospholipid antibodies in neonates with stroke--a unique entity or variant of antiphospholipid syndrome?

OBJECTIVE

YB current affiliation: Department of Pediatrics, Hadassah-Hebrew University Medical Center, Mount Scopus, Israel YB and MJS contributed equally to the study and should be regarded as joint first authors on this manuscript. Antiphospholipid syndrome (APS) may present with thrombosis and persistently elevated titers of antiphospholipid antibodies (aPL) in the neonatal period. Our aim was to investigate the course and impact of elevated titers of aPL in a cohort of infants presenting with either perinatal arterial ischemic stroke (PAS) or cerebral sinus vein thrombosis (CSVT) during the perinatal period.

STUDY DESIGN

Sixty-two infants with clinically and radiologically confirmed PAS or CSVT presenting in the neonatal period underwent thrombophilia workup that included Factor V Leiden (FVL), PII20210A mutation, MTHFR 677T polymorphism, protein C, protein S, aPL namely either circulating lupus anticoagulant (CLA), anticardiolipin antibodies (aCL) or anti-β2-glycoprotein-1 (β2GP1). Mothers also underwent thrombophilia workup.

RESULTS

Twelve infants with persistently elevated aPL were prospectively followed. Infants with positive aPL showed no concordance with presence of maternal aPL. All children were followed for a median of 3.5 years (range: nine months to 19 years) with repeated aPL testing every three to six months. Anticoagulant therapy initiation and therapy duration varied at the physician's discretion. In 10/12 cases aPL decreased to normal range within 2.5 years; one female with complex thrombophilia risk factors required indefinite prolonged anticoagulation. None of the infants showed recurrent thrombosis or any other APS manifestations, despite lack of prolonged anticoagulation.

CONCLUSIONS

The presence of aPL may be important in the pathogenesis of cerebral thrombosis in neonates. Nevertheless, the nature of thrombophilia interactions in this period and their therapeutic impact warrants further investigation.

The Effect of Testosterone on Cardiovascular Disease

Cardiovascular disease is the leading cause of death in the United States. Testosterone is the principal male sex hormone and plays an important role in men’s health and well-being. Historically, testosterone was believed to adversely affect cardiovascular function. However, contemporary literature has refuted this traditional thinking; testosterone has been suggested to have a protective effect on cardiovascular function through its effects on the vascular system. Data from modern research indicate that hypogonadism is closely related to the development of various cardiovascular risk factors, including hyperlipidemia and insulin resistance. Several studies have demonstrated beneficial effects of testosterone supplementation therapy on reversing symptoms of hypogonadism and improving cardiovascular disease risk profiles. In this review, we perform a critical analysis on the association between testosterone and cardiovascular disease.

Review of lipid and lipoprotein(a) abnormalities in childhood arterial ischemic stroke

National organizations recommend cholesterol screening in children to prevent vascular disease in adulthood. There are currently no recommendations for cholesterol and lipoprotein (a) testing in children who experience an arterial ischemic stroke. While dyslipidemia and elevated lipoprotein (a) are associated with ischemic stroke in adults, the role of atherosclerotic risk factors in childhood arterial ischemic stroke is not known. A review of the literature was performed from 1966 to April 2012 to evaluate the association between childhood arterial ischemic stroke and dyslipidemia or elevated lipoprotein (a). Of 239 citations, there were 16 original observational studies in children (with or without neonates) with imaging-confirmed arterial ischemic stroke and data on cholesterol or lipoprotein (a) values. Three pairs of studies reported overlapping subjects, and two were eliminated. Among 14 studies, there were data on cholesterol in 7 and lipoprotein (a) in 10. After stroke, testing was performed at >three-months in nine studies, at ≤three-months in four studies, and not specified in one study. There were five case-control studies: four compared elevated lipoprotein (a) and one compared abnormal cholesterol in children with arterial ischemic stroke to controls. A consistent positive association between elevated lipoprotein (a) and stroke was found [Mantel-Haenszel OR 4·24 (2·94-6·11)]. There was no association in one study on total cholesterol, and a positive association in one study on triglycerides. The literature suggests that elevated lipoprotein (a) may be more likely in children with arterial ischemic stroke than in control children. The absence of confirmatory study on dyslipidemia should be addressed with future research.

Iron deficiency anemia as a risk factor for cerebrovascular events in early childhood: a case-control study

In recent years, iron-deficiency anemia (IDA) has been suggested to have an association with childhood-onset ischemic stroke in otherwise healthy children, but few cases have proven it thus far. In this study, we aimed to investigate whether iron-deficiency anemia is a risk factor for cerebrovascular events and childhood-onset ischemic stroke in previously healthy children. This was a case-control study that included 21 stroke cases with patients who had previously been generally healthy, and matched with age and gender of 100 healthy control subjects. Patients were included if a diagnosis of definite stroke had been made and other known etiologies of childhood onset stroke were excluded. For all subjects, iron parameters including serum iron, ferritin, transferrin, total iron binding capacity, and transferrin saturation were assessed. We screened all case patients for prothrombotic factors including level of hemoglobin S, protein C, protein S, antithrombin III, lupus anticoagulant, factor V Leiden, and prothrombin gene mutation (G20210A). Brain magnetic resonance images (MRI), magnetic resonance angiography (MRA), and magnetic resonance venography (MRV) were performed to all case patients. All case patients have normal results regarding functional, immunological, and molecular assay for prothrombotic factors screening. Our results showed that IDA was disclosed in 57.1 % of stroke cases with no identified cause, as compared to 26 % of controls. Our study suggest that previously healthy children who developed stroke are 3.8 times more likely to have IDA than healthy children, who do not develop stroke (OR, 3.8; 95 % CI:1.3-11.2 P = 0.005). In addition, there was significant interaction between IDA and thrombocytosis among studied cases (OR, 10.5; 95 % CI, 1.0-152 P = 0.02). There were nonsignificant differences between stroke patients with IDA and those with normal iron parameters regarding stroke subtype (P > 0.05). Public health messages on the importance of early detection of iron-deficiency anemia in young children, especially in our developing countries so that it can be treated before a life-threatening complication like stroke develops.

Therapy in pediatric stroke

The aim of this review is to summarize the existing literature on therapy and management of cerebrovascular insults in children and adolescents. As data sources, studies were identified by MEDLINE, PubMed, Cochrane Library, and relevant bibliographies for the topic "pediatric stroke." We also reviewed guidelines for "stroke in adults." As a result, pediatric stroke is underestimated. The annual incidence for all stroke entities (cerebral venous thrombosis and hemorrhagic and arterial ischemic stroke) is as high as for pediatric brain tumors, 3-15/100.000 children per year. A distinct etiology can be determined only in a minority of them. Underlying risk factors are multiple, mainly vasculopathies, congential heart diseases, coagulopathies, lipometabolic disorders, and sickle cell anemia. Current recommendations for therapy are based on adult studies, are preliminary, and discussed controversially. Antithrombotic therapy is uniformly recommended for the acute stage of pediatric stroke; no consensus exists on antiplatelet therapy with acetylsalicylic acid (ASA, aspirin) (5 mg/d), with ultra-fractionated or low-molecular-weight heparin. Thrombolysis using recombinant tissue plasminogen activator is not advised, despite the fact that current practice takes a different approach. None of the guidelines specify the duration of ASA for secondary prevention. Additional supportive therapy measures are osmotherapy and decompressive craniectomy. Oxygen in the absence of hypoxemia, intensive insulin therapy, antiepileptic drugs in the absence of clinical or electrographic seizures, corticosteroids, and GP-IIb/IIIa-receptor antagonists should not be used outside clinical trials. In conclusions, current therapeutic guidelines for pediatric stoke are still based on consensus and expert and society opinions and differ between countries. Consensus prevails on the need for acute anticoagulation using either antiplatelets or heparin. Long-term treatment with acetylsalicylic acid in all or only high-risk patients and for how long remains the subject of debate. Lifelong secondary prevention has never been investigated in children or adults. All guidelines agree that there is no indication for thrombolysis in children outside clinical trials, although clinical practice in large centers differs.

Cerebrovascular disorders in childhood

Cerebrovascular problems in childhood include diverse problems of vascular supply to the brain and occur with an overall frequency of from 5 to 8/100000 children/year. Signs and symptoms at manifestation are manifold. They depend not only on localization of the infarction but also on age at injury and specific risk factors. Acute arterial ischemic insult in neonates is oligosymptomatic (short-lasting seizures); hemiparesis is the most common symptom in children. Risk factors are multiple for both neonates and children, with more thromboembolic events in neonates and (infection-related) vasculopathies or cardiac problems in children. MRI (diffusion weighted) is the golden standard for diagnosis. In the absence of evidence for treatment in both groups, guidelines suggest use of platelet aggregation. There are some special indications for anticoagulation. Thrombolysis should be evaluated. Two-thirds of children and neonates face lifelong neurological and neuropsychological problems. Spinal artery ischemia presents with acute spinal symptoms, mostly paraplegia. Risk factors and prognosis are similar to cerebral insults. Sinus venous thromboses are significantly less common. Provoking factors in newborns are mainly neonatal problems, and in children infections, especially in the ENT region. For diagnosis the delta sign in CT is less sensitive than MR/MR venography. In the absence of any evidence, LMWH or heparinization for 3-6 months are recommended. Prognosis is better in children than in neonates. Deep vein thrombosis and/or young age worsen the outcome.

Reversible cerebral vasoconstriction syndrome: rare or underrecognized in children?

Reversible cerebral vasoconstriction syndrome (RCVS) is a clinicoradiological diagnosis comprising 'thunderclap' headaches and reversible segmental vasoconstriction of cerebral arteries, occasionally complicated by ischaemic or haemorrhagic stroke. We report a case of RCVS in a 13-year-old male with severe thunderclap headaches and no focal neurological signs. Brain imaging showed multiple posterior circulation infarcts; cerebral computed tomography, magnetic resonance imaging, and catheter angiography showed multifocal irregularity and narrowing, but in different arterial segments. Laboratory studies did not support a diagnosis of vasculitis. Symptoms resolved over 3 weeks; magnetic resonance angiography 3 months later was normal and remained so after 2 years. We highlight the typical clinical features of RCVS in this case and suggest that the diagnosis should be considered in children with thunderclap headaches or stroke syndromes where headache is a prominent feature, especially if cerebrovascular imaging studies appear to be evolving or discrepant.

ADVANCES IN THE CELL-BASED TREATMENT OF NEONATAL HYPOXIC-ISCHEMIC BRAIN INJURY

Stem cell therapy for adult stroke has reached limited clinical trials. Here, we provide translational research guidance on stem cell therapy for neonatal hypoxic-ischemic brain injury requiring a careful consideration of clinically relevant animal models, feasible stem cell sources, and validated safety and efficacy endpoint assays, as well as a general understanding of modes of action of this cellular therapy. To this end, we refer to existing translational guidelines, in particular the recommendations outlined in the consortium of academicians, industry partners and regulators called Stem cell Therapeutics as an Emerging Paradigm for Stroke or STEPS. Although the STEPS guidelines are directed at enhancing the successful outcome of cell therapy in adult stroke, we highlight overlapping pathologies between adult stroke and neonatal hypoxic-ischemic brain injury. We are, however, cognizant that the neonatal hypoxic-ischemic brain injury displays disease symptoms distinct from adult stroke in need of an innovative translational approach that facilitates the entry of cell therapy in the clinic. Finally, insights into combination therapy are provided with the vision that stem cell therapy may benefit from available treatments, such as hypothermia, already being tested in children diagnosed with hypoxic-ischemic brain injury.

Sex, stroke, and inflammation: the potential for estrogen-mediated immunoprotection in stroke

Stroke is the third leading cause of death and the primary cause of disability in the developed world. Experimental and clinical data indicate that stroke is a sexually dimorphic disease, with males demonstrating an enhanced intrinsic sensitivity to ischemic damage throughout most of their lifespan. The neuroprotective role of estrogen in the female brain is well established, however, estrogen exposure can also be deleterious, especially in older women. The mechanisms for this remain unclear. Our current understanding is based on studies examining estrogen as it relates to neuronal injury, yet cerebral ischemia also induces a robust sterile inflammatory response involving local and systemic immune cells. Despite the potent anti-inflammatory effects of estrogen, few studies have investigated the contribution of estrogen to sex differences in the inflammatory response to stroke. This review examines the potential role for estrogen-mediated immunoprotection in ischemic injury.

Neonatal testosterone exposure protects adult male rats from stroke

BACKGROUND

Men have a higher stroke incidence compared to women until advanced age. The contribution of hormones to these sex differences has been extensively debated. In experimental stroke, estradiol is neuroprotective, whereas androgens are detrimental. However, prior studies have only examined the effects of acute treatment paradigms; therefore, the timing and mechanism by which ischemic sexual dimorphism arises are unknown.

METHODS

The effects of exogenous neonatal androgen exposure on subsequent injury induced by middle cerebral artery occlusion in adulthood in male rats were examined. Rats were administered vehicle (oil), testosterone propionate (TP) or the non-aromatizable androgen dihydrotestosterone (DHT) for 5 days after birth. At 3 months of age, a focal stroke was induced.

RESULTS

Testosterone-treated rats (but not DHT-treated animals) had decreased infarct volumes (20 vs. 33%, p < 0.05) as well as increased estradiol levels (39.4 vs. 18.6 pg/ml, p < 0.0001) compared to oil-treated animals. TP-injected males had increased testicular aromatase (P450arom) levels (3.6 vs. 0.2 ng/ml, p < 0.0001) compared to oil-treated males. The level of X-linked inhibitor of apoptosis, the primary endogenous inhibitor of caspase-induced apoptosis, was increased in TP-treated rats compared with the oil-treated males.

CONCLUSIONS

Neonatal exposure to exogenous testosterone upregulates testicular aromatase expression in male rats and leads to adult neuroprotection secondary to changes in serum estradiol levels and cell death proteins. This study suggests that early exposure to gonadal hormones can have dramatic effects on the response to adult cerebrovascular injury.

Basilar artery stroke in childhood

AIM

Little is known about basilar artery stroke (BAS) in children. The objective of this study was to calculate the incidence of BAS in children and to analyse the clinical presentation, risk factors, radiological findings, therapeutic approaches, and outcome of BAS in childhood.

METHOD

A prospective, population-based study including children with arterial ischaemic stroke and a systematic review of the literature was undertaken.

RESULTS

Seven children with BAS were registered at the Swiss Neuropaediatric Stroke Registry between January 2000 and June 2011 (incidence 0.037 per 100,000 children per year, 95% confidence interval [CI] 0.013-0.080). A further 90 cases were identified through the literature search. The majority of patients were male (73 males, 24 females) and the median age was 9 years (interquartile range [IQR]=6-13y). The median Pediatric National Institutes of Health Stroke Scale (PedNIHSS) score was 15 (IQR=4-27). Presenting signs and symptoms comprised impaired consciousness (n=64), quadri- or hemiparesis (n=58), bulbar dysfunction (n=46), vomiting, nausea (n=43), and headache (n=41). Prodromes occurred in 43% of cases. Aetiology was largely vasculopathic (n=38), but often unknown (n=40). Time to diagnosis varied from hours days; six patients received antithrombotic, thrombolytic, or mechanical endovascular treatment 12 hours or less after symptom onset. Outcome was good (modified Rankin Scale 0-2) in 45 patients; eight died. PedNIHSS score of up to 17 was a prognostic factor for good outcome.

INTERPRETATION

BAS is rare in children. Compared with adults, outcome is more favourable despite a considerable delay in diagnosis and treatment. Outcome was better in children with a PedNIHSS score of 17 or less.

Interactions between age, sex, and hormones in experimental ischemic stroke

Age, sex, and gonadal hormones have profound effects on ischemic stroke outcomes, although how these factors impact basic stroke pathophysiology remains unclear. There is a plethora of inconsistent data reported throughout the literature, primarily due to differences in the species examined, the timing and methods used to evaluate injury, the models used, and confusion regarding differences in stroke incidence as seen in clinical populations vs. effects on acute neuroprotection or neurorepair in experimental stroke models. Sex and gonadal hormone exposure have considerable independent impact on stroke outcome, but these factors also interact with each other, and the contribution of each differs throughout the lifespan. The contribution of sex and hormones to experimental stroke will be the focus of this review. Recent advances and our current understanding of age, sex, and hormone interactions in ischemic stroke with a focus on inflammation will be discussed.

Thrombophilia testing in neonates and infants with thrombosis

In neonates and infants with idiopathic venous thrombosis (VTE) and in pediatric populations in which thromboses were associated with medical diseases, inherited thrombophilia (IT) have been described as risk factors. Follow-up data for VTE recurrence in neonates suggest a recurrence rate between 3% in provoked and 21% in idiopathic VTE. Apart from underlying medical conditions, recently reported systematic reviews on pediatric VTE have shown significant associations between factor V G1691A, factor II G20210A, and deficiencies of protein C, protein S and antithrombin, even more pronounced when combined IT were involved. Independent from the age at first VTE onset, the pooled odds ratios (OR: single IT) for VTE ranged from 2.4 for the factor II G20210A mutation to 9.4 in neonates and infants with antithrombin deficiency. The pooled OR for persistent antiphospholipid antibodies/lupus anticoagulants was 4.9 for pediatric patients with venous VTE. The factor II G20210A mutation (OR: 2.1), and deficiencies of protein C (OR: 2.4), S (OR: 3.1) and antithrombin (OR: 3.0) also played a significant role at recurrence. Based on these data, screening and treatment algorithms must be discussed.