Vulnerability to stroke: implications of perinatal programming of the hypothalamic-pituitary-adrenal axis

Long daytime napping: A silent danger for hypertensive individuals

BACKGROUND AND PURPOSE

Hypertension significantly contributes to stroke. Previous research has indicated a connection between daytime napping and stroke. Research on the connection between daytime napping duration and first stroke in hypertensive individuals is lacking nevertheless.

METHODS

This research, which ran from 24 August 2013 to 31 December 2022, recruited 11,252 individuals with hypertension and without a history of stroke from the China Stroke Primary Prevention Trial. To determine the relationship between daytime napping duration and stroke onset in hypertensive individuals, we conducted analyses for threshold effects, multivariate-adjusted Cox proportional hazard regression models, and Kaplan-Meier survival curves.

RESULTS

The duration of daytime napping (<75 min) was positively correlated with stroke risk; beyond 75 min, the risk did not increase further. When compared to hypertensive individuals who napped for 1-30 min, daytime napping 31-60 min (hazard ratio [HR] = 1.27, 95% confidence interval [CI] = 1.06-1.53) and >60 min (HR = 1.37, 95% CI = 1.14-1.65) were substantially related with a greater risk of first stroke. Additionally, this correlation was absent in cases of hemorrhagic stroke, but present in cases of ischemic stroke, specifically for hypertensive individuals who napped for 31-60 min or >60 min (p < 0.05). Kaplan-Meier survival curves displayed that hypertensive individuals who extended daytime napping had an elevated incidence of stroke.

CONCLUSIONS

Hypertensive individuals who take longer daytime naps (>30 min) are at an elevated risk of stroke onset, particularly ischemic stroke, irrespective of other factors.

Microglia Involves in the Immune Inflammatory Response of Poststroke Depression: A Review of Evidence

Poststroke depression (PSD) does not exist before and occurs after the stroke. PSD can appear shortly after the onset of stroke or be observed in the weeks and months after the acute or subacute phase of stroke. The pathogenesis of PSD is unclear, resulting in poor treatment effects. With research advancement, immunoactive cells in the central nervous system, particularly microglia, play a role in the occurrence and development of PSD. Microglia affects the homeostasis of the central nervous system through various factors, leading to the occurrence of depression. The research progress of microglia in PSD has been summarized to review the evidence regarding the pathogenesis and treatment target of PSD in the future.

Dysregulated Hypothalamic–Pituitary–Adrenal Axis Is Associated With Increased Inflammation and Worse Outcomes After Ischemic Stroke in Diabetic Mice

Diabetic patients have larger infarcts, worse neurological deficits, and higher mortality rate after an ischemic stroke. Evidence shows that in diabetes, the hypothalamic–pituitary–adrenal (HPA) axis was dysregulated and levels of cortisol increased. Based on the role of the HPA axis in immunity, we hypothesized that diabetes-dysregulated stress response exacerbates stroke outcomes via regulation of inflammation. To test this hypothesis, we assessed the regulation of the HPA axis in diabetic mice before and after stroke and determined its relevance in the regulation of post-stroke injury and inflammation. Diabetes was induced in C57BL/6 mice by feeding a high-fat diet and intraperitoneal injection of streptozotocin (STZ), and then the mice were subjected to 30 min of middle cerebral artery occlusion (MCAO). Infarct volume and neurological scores were measured in the ischemic mice. The inflammatory cytokine and chemokine levels were also determined in the ischemic brain. To assess the effect of diabetes on the stroke-modulated HPA axis, we measured the expression of components in the HPA axis including corticotropin-releasing hormone (CRH) in the hypothalamus, proopiomelanocortin (POMC) in the pituitary, and plasma adrenocorticotropic hormone (ACTH) and corticosterone. Diabetic mice had larger infarcts and worse neurological scores after stroke. The exacerbated stroke outcomes in diabetic mice were accompanied by the upregulated expression of inflammatory factors (including IL-1β, TNF-α, IL-6, CCR2, and MCP-1) in the ischemic brain. We also confirmed increased levels of hypothalamic CRH, pituitary POMC, and plasma corticosterone in diabetic mice before and after stroke, suggesting the hyper-activated HPA axis in diabetic conditions. Finally, we confirmed that post-stroke treatment of metyrapone (an inhibitor of glucocorticoid synthesis) reduced IL-6 expression and the infarct size in the ischemic brain of diabetic mice. These results elucidate the mechanisms in which the HPA axis in diabetes exacerbates ischemic stroke. Maintaining an optimal level of the stress response by regulating the HPA axis may be an effective approach to improving stroke outcomes in patients with diabetes.

Association of daytime napping with incident stroke in middle-aged and older adults: a large community-based study

BACKGROUND AND PURPOSE

There are conflicting reports on the association between daytime napping and incident stroke. This study was designed to investigate the relationship between daytime napping and stroke within a community-based cohort.

METHODS

The present prospective study was based on the Sleep Heart Health Study. Napping habits were assessed with a self-reported Sleep Habits Questionnaire. Participants with napping habits of different durations and frequencies were followed up until the first stroke occurred or the final censoring date. Cox proportional hazards models were used to estimate the relationship between napping habits and stroke.

RESULTS

A total of 4757 participants (2219 men, mean age 63.6 ± 11.1 years) were enrolled in this study. Compared with those taking no naps, multivariate proportional hazards models analysis indicated that individuals taking naps with a duration of >60 min [hazard ratio (HR), 2.460; 95% confidence interval (CI), 1.538-3.934] had a higher risk of stroke. There was also an increased risk of stroke among participants taking naps daily (HR, 1.563; 95% CI, 1.059-2.307) or five to six times/week (HR, 1.548; 95% CI, 1.026-2.335). After combining napping durations and frequencies, regular long naps (HR, 1.903; 95% CI, 1.182-3.065) and regular short naps (HR, 1.451; 95% CI, 1.010-2.084) were independent risk factors for incident stroke.

CONCLUSION

Daytime napping with a long duration (>30 min) or a high frequency (≥5 times/week) may increase the risk of stroke.

Risk of stroke among patients with borderline personality disorder: A nationwide longitudinal study

BACKGROUND

Previous studies suggested that patients with borderline personality disorder (BPD) had a higher prevalence of stroke-related risk factors, such as hypertension, dyslipidemia, and diabetes mellitus. But, the association between BPD and subsequent stroke has been rarely investigated.

METHODS

Using the Taiwan National Health Insurance Research Database, 5969 borderline patients aged 18 years and older and 23,876 age-and sex-matched controls were enrolled between 2002 and 2009, and followed up to the end of 2011 to identify the development of stroke.

RESULTS

The Cox regression model after adjusting for demographic data, psychiatric comorbidities, and medical comorbidities showed that BPD was associated with an increased risk of developing any stroke (HR: 4.82, 95% CI: 2.77-8.40) and ischemic stroke (HR: 5.67, 95% CI: 2.49-12.93). The findings of sensitivity analysis after excluding the first year of observation were consistent: any stroke (HR: 3.44, 95% CI: 1.83-6.47) and ischemic stroke (HR: 4.75, 95% CI: 1.91-11.77).

DISCUSSION

Patients with BPD had an elevated vulnerability to subsequent stroke and ischemic stroke compared to those without BPD. Further studies would be required to investigate the underlying mechanisms.

Evidence for Ancestral Programming of Resilience in a Two-Hit Stress Model

In a continuously stressful environment, the effects of recurrent prenatal stress (PS) may accumulate across generations and alter stress vulnerability and resilience. Here, we report in female rats that a family history of recurrent ancestral PS facilitates certain aspects of movement performance, and that these benefits are abolished by the experience of a second hit, induced by a silent ischemia during adulthood. Female F4-generation rats with and without a family history of cumulative multigenerational PS (MPS) were tested for skilled motor function before and after the induction of a minor ischemic insult by endothelin-1 infusion into the primary motor cortex. MPS resulted in improved skilled motor abilities and blunted hypothalamic-pituitary-adrenal (HPA) axis function compared to non-stressed rats. Deep sequencing revealed downregulation of miR-708 in MPS rats along with upregulation of its predicted target genes Mapk10 and Rasd2. Through miR-708 stress may regulate mitogen-activated protein kinase (MAPK) pathway activity. Hair trace elemental analysis revealed an increased Na/K ratio, which suggests a chronic shift in adrenal gland function. The ischemic lesion activated the HPA axis in MPS rats only; the lesion, however, abolished the advantage of MPS in skilled reaching. The findings indicate that MPS generates adaptive flexibility in movement, which is challenged by a second stressor, such as a neuropathological condition. Thus, a second “hit” by a stressor may limit behavioral flexibility and neural plasticity associated with ancestral stress.

Comparing Variability, Severity, and Persistence of Depressive Symptoms as Predictors of Future Stroke Risk

OBJECTIVE

Numerous studies show that depressive symptoms measured at a single assessment predict greater future stroke risk. Longer-term symptom patterns, such as variability across repeated measures or worst symptom level, might better reflect adverse aspects of depression than a single measurement. This prospective study compared five approaches to operationalizing depressive symptoms at annual assessments as predictors of stroke incidence.

DESIGN

Cohort followed for incident stroke over an average of 6.4 years.

SETTING

The Adult Changes in Thought cohort follows initially cognitively intact, community- dwelling older adults from a population base defined by membership in Group Health, a Seattle-based nonprofit healthcare organization.

PARTICIPANTS

3,524 individuals aged 65 years and older.

MEASUREMENTS

We identified 665 incident strokes using ICD codes. We considered both baseline Center for Epidemiologic Studies-Depression scale (CES-D) score and, using a moving window of three most recent annual CES-D measurements, we compared most recent, maximum, average, and intra-individual variability of CES-D scores as predictors of subsequent stroke using Cox proportional hazards models.

RESULTS

Greater maximum (hazard ratio [HR]: 1.18; 95% CI: 1.07-1.30), average (HR: 1.20; 95% CI: 1.05-1.36) and intra-individual variability (HR: 1.15; 95% CI: 1.06-1.24) in CES-D were each associated with elevated stroke risk, independent of sociodemographics, cardiovascular risks, cognition, and daily functioning. Neither baseline nor most recent CES-D was associated with stroke. In a combined model, intra-individual variability in CES-D predicted stroke, but average CES-D did not.

CONCLUSIONS

Capturing the dynamic nature of depression is relevant in assessing stroke risk. Fluctuating depressive symptoms may reflect a prodrome of reduced cerebrovascular integrity.

Evidence of lasting dysregulation of neuroendocrine and HPA axis function following global cerebral ischemia in male rats and the effect of Antalarmin on plasma corticosterone level

Abnormal function of the neuroendocrine stress system has been implicated in the behavioral impairments observed following brain ischemia. The current study examined long-term changes in stress signal regulation 30days following global cerebral ischemia. Experiment 1 investigated changes in the expression of corticotropin releasing hormone (CRH) and its subtype 1 receptor (CRHR1), glucocorticoid receptors (GR) in the paraventricular nucleus of the hypothalamus (PVN), the central nucleus of the amygdala (CeA), and the CA1 subfield of the hippocampus. Tyrosine hydroxylase (TH) was determined at the locus coeruleus (LC). Experiment 2 investigated the role of central CRHR1 activation on corticosterone (CORT) secretion at multiple time intervals following global ischemia after exposure to an acute stressor. Findings from Experiment 1 demonstrated a persistent increase in GR, CRH and CRHR1 immunoreactivity (ir) at the PVN, reduced GR and CRHR1 expression in pyramidal CA1 neurons, and increased LC TH expression in ischemic rats displaying working memory errors in the radial arm Maze. Findings from Experiment 2 revealed increased CORT secretion up to 7 days, but no longer present 14 and 21 days post ischemia. However upon an acute restraint stress induced 27 days following reperfusion, ischemic rats had increased plasma CORT secretions compared to sham-operated animals, suggesting HPA axis hypersensitivity. Antalarmin (2 μg/2 μl) pretreatment significantly attenuated post ischemic elevation of basal and stress-induced CORT secretion. These findings support persistent neuroendocrine dysfunctions following brain ischemia likely to contribute to emotional and cognitive impairments observed in survivors of cardiac arrest and stroke.

The neuroendocrine control of the innate immune system in health and brain diseases

The innate immune reaction takes place in the brain during immunogenic challenges, injury, and disease. Such a response is highly regulated by numerous anti-inflammatory mechanisms that may directly affect the ultimate consequences of such a reaction within the cerebral environment. The neuroendocrine control of this innate immune system by glucocorticoids is critical for the delicate balance between cell survival and damage in the presence of inflammatory mediators. Glucocorticoids play key roles in regulating the expression of inflammatory genes, and they also have the ability to modulate numerous functions that may ultimately lead to brain damage or repair after injury. Here we review these mechanisms and discuss data supporting both neuroprotective and detrimental roles of the neuroendocrine control of innate immunity.