Role of endogenous testosterone concentration in pediatric stroke

Sexual dimorphism in ischemic stroke: lessons from the laboratory

Ischemic stroke is emerging as a major health problem for elderly women. Women have lower stroke incidence than men until an advanced age, when the epidemiology of ischemic stroke shifts and incidence rises dramatically in women. Experimental models of rodent stroke have replicated this clinical epidemiology, with exacerbated injury in older compared with young female rodents. Many of the detrimental effects of aging on ischemic stroke outcome in females can be replicated by ovariectomy, suggesting that hormones such as estrogen play a neuroprotective role. However, emerging data suggest that the molecular mechanisms leading to ischemic cell death differ in the two sexes, and these effects may be independent of circulating hormone levels. This article highlights recent clinical and experimental literature on sex differences in stroke outcomes and mechanisms.

Baby STEPS: a giant leap for cell therapy in neonatal brain injury

We advance Baby STEPS or Stem cell Therapeutics as an Emerging Paradigm in Stroke as a guide in facilitating the critical evaluation in the laboratory of the safety and efficacy of cell therapy for neonatal encephalopathy. The need to carefully consider the clinical relevance of the animal models in mimicking human neonatal brain injury, selection of the optimal stem cell donor, and the application of functional outcome assays in small and large animal models serve as the foundation for preclinical work and beginning to understand the mechanism of this cellular therapy. The preclinical studies will aid our formulation of a rigorous human clinical trial that encompasses not only efficacy testing but also monitoring of safety indices and demonstration of mechanisms of action. This schema forms the basis of Baby STEPS. Our goal is to resonate the urgent call to enhance the successful translation of cell therapy from the laboratory to the clinic.

Sex differences in cerebral ischemia: possible molecular mechanisms

Sex is emerging as an important factor in the etiology and expression of many different pathological conditions, including stroke. Initially, the levels of sex hormones were thought to be the major contributor to these sex differences, especially after puberty, when gonadal steroid levels sharply diverge between the sexes. More recently, it is recognized that sex differences also result from the organizational effects of sex hormone exposure early in development, even in the absence of hormone exposure later in life, as well as effects mediated by the sex chromosomes themselves. Epigenetic modifications of developmental genes important in sexual differentiation and the response to sex steroid hormones are also emerging as another important contributor to sex differences in disease expression. This review describes recent research on the relationship between hormones, organizational-activational effects of gonadal steroids, and epigenetic modifications in brain pathology, focusing specifically on cerebral ischemia.

Recent advances in childhood arterial ischemic stroke

Although many underlying diseases have been reported in the setting of childhood arterial ischemic stroke, emerging research demonstrates that non-atherosclerotic intracerebral arteriopathies in otherwise healthy children are prevalent. Minor infections may play a role in arteriopathies that have no other apparent underlying cause. Although stroke in childhood differs in many aspects from adult stroke, few systematic studies specific to pediatrics are available to inform stroke management. Treatment trials of pediatric stroke are required to determine the best strategies for acute treatment and secondary stroke prevention. The high cost of pediatric stroke to children, families, and society demands further study of its risk factors, management, and outcomes. This review focuses on the recent findings in childhood arterial ischemic stroke.

Neonatal Cerebral Sinovenous Thrombosis From Symptom to Outcome

Background and Purpose— Cerebral sinovenous thrombosis is a rare disease with severe neurological sequelae. The aim of this retrospective multicenter study was to investigate the clinical course, possible risk factors, and outcome of a cohort of neonatal patients with sinovenous thrombosis and, second, to estimate the incidence in The Netherlands.

Methods— From January 1999 to March 2009, a review of all neonatal patients with sinovenous thrombosis from 6 tertiary neonatal intensive care units was performed. Population characteristics, clinical presentation, (prothrombotic) risk factors, neuroimaging, interventions, and neurodevelopment were evaluated. An estimated incidence was calculated based on the Netherlands Perinatal Registry.

Results— Fifty-two neonates were included (39 boys) with a median gestational age of 39 weeks (range, 30 to 42 weeks; 5 preterm). An assisted or complicated delivery occurred in 32 of 52. Presenting symptoms developed at a median postnatal age of 1.5 days (range, 0 to 28 days) and consisted mainly of seizures (29 of 52). All sinovenous thrombosis cases were confirmed with MRI/MR venography. Multisinus thrombosis was most common followed by superior sagittal sinus thrombosis. FII G20210A mutation was present in 2 of 18 tested neonates (11%). Anticoagulation therapy (in 22 of 52) did not result in hemorrhagic complications. At follow-up (median age, 19 months; range, 3 to 72 months), moderate to severe neurological sequelae were present in 38%. The mortality was 10 of 52 (19%). A variable, although high yearly incidence of 1.4 to 12 per 100 000 term newborns was found.

Conclusions— Neonatal sinovenous thrombosis is a multifactorial disease. The estimated incidence in The Netherlands seems higher than reported elsewhere.