The role of neuroendocrine pathways in prognosis after stroke

Voacangine mitigates oxidative stress and neuroinflammation in middle cerebral artery occlusion-induced cerebral ischemia/reperfusion injury by averting the NF-κBp65/MAPK signaling pathways in rats

Ischemic stroke is a leading cause of human mortality. Cerebral ischemia-reperfusion injury (CI/RI) is a primary cause of stroke. Ischemia-reperfusion (I/R) resulting in oxidative stress and inflammatory events may lead to severe neuronal impairments. Thus, anti-oxidative and anti-inflammatory mediators that can alleviate post-I/R neuronal injuries are required for the treatment of CI/RI. An alkaloid, voacangine (VCG) is a recognized antioxidant, anti-inflammatory, and anticancer agent. Hence, the current study intended to explore the neuroprotective potential and the principal mechanisms of VCG in CI/RI. The experimental rats were divided into four sets: control, I/R-induced, I/R + VCG (2.5 mg/kg), I/R + VCG (5 mg/kg). CI/RI was induced by implanting a thread into the middle cerebral artery occlusion (MCAO) model. Brain damages were assessed on the basis of brain edema, brain infarct volume, neurological deficit score, histopathology, oxidative stress, and neuroinflammation. Results revealed that VCG inhibited the triggering of NLRP3 inflammasome, pro-inflammatory cytokines, lipid peroxidation, but enhanced the antioxidant status in MCAO rats. Furthermore, VCG treatment averted brain damage by I/R, neuroinflammation, and oxidative stress by suppressing NF-κBp65/MAPK pathways. The results of the study provide pertinent insights pertaining to the role of VCG as a potential neuroprotective agent against ischemic stroke.

Whether serum leptin and insulin-like growth factor-1 are predictive biomarkers for post-stroke depression: A meta-analysis and systematic review

Leptin and insulin-like growth factor-1 (IGF-1) may play a role in clinical identification of post-stroke depression (PSD). Here, eight databases (including CNKI, Wanfang, SinoMed, VIP, PubMed, the Cochrane Library, Embase, and the Web of Science) were employed to search for studies on serum leptin and insulin-like growth factor-1 expression levels in patients with PSD. In total, 13 articles were included, of which 6 studies investigated the expression level of serum leptin in patients with PSD, 7 studies explored the serum IGF-1 in PSD patients. Then, the RevMan 5.4 software was used for meta-analysis. The results showed that serum leptin levels were significantly higher in PSD patients than in patients without PSD (SMD = 1.54, 95% CI: 0.84, 2.23; P = 0.006). The result of subgroup analysis showed that the serum leptin levels in PSD patients were significantly higher than those without PSD in acute phase (SMD = 1.38, 95% CI: 0.04, 2.71; P = 0.04), subacute phase (SMD = 2.31, 95% CI: 0.88, 3.73; P = 0.001), and chronic phase (SMD = 1.02, 95% CI: 0.43, 1.60; P = 0.0007); There was no significant difference in serum IGF-1 level between PSD patients and patients without PSD (SMD = 0.49, 95% CI: -0.55, 1.52; P = 0.36). Moreover, the subgroup analysis also showed that there was no statistical difference in acute stage (SMD = 0.36, 95% CI: 0.89, 1.60; P = 0.57). Our study provides evidence to prove that serum leptin level has potential clinical application value as biomarkers for identifying PSD.

Investigating the Potential Mechanisms and Therapeutic Targets of Inflammatory Cytokines in Post-stroke Depression

Post-stroke depression (PSD) affects approximately one-third of stroke survivors, severely impacting general recovery and quality of life. Despite extensive studies, the exact mechanisms underlying PSD remain elusive. However, emerging evidence implicates proinflammatory cytokines, including interleukin-1β, interleukin-6, tumor necrosis factor-alpha, and interleukin-18, play critical roles in PSD development. These cytokines contribute to PSD through various mechanisms, including hypothalamic-pituitary-adrenal (HPA) axis dysfunction, neurotransmitter alterations, neurotrophic factor changes, gut microbiota imbalances, and genetic predispositions. This review is aimed at exploring the role of cytokines in stroke and PSD while identifying their potential as specific therapeutic targets for managing PSD. A more profound understanding of the mechanisms regulating inflammatory cytokine expression and anti-inflammatory cytokines like interleukin-10 in PSD may facilitate the development of innovative interventions to improve outcomes for stroke survivors experiencing depression.

Predictive value of the systemic immune inflammation (SII) index for stroke-associated pneumonia

OBJECTIVE

To investigate the predictive value of the systemic immune inflammation (SII) index on the occurrence of stroke-associated pneumonia (SAP) in patients with acute stroke.

METHODS

Data of patients with or without a previous history of pulmonary who visited the First Affiliated Hospital of Kunming Medical University within 24 h of the onset of stroke were collected between January 2017 and December 2019. Patient's demographic data, stroke type, past medical history, National Institutes of Health Stroke Scale score, Glasgow Coma score, and laboratory tests were collected. Logistic regression models and receiver-operating characteristic (ROC) curves were used to investigate the predictive value of SII for the development of SAP in patients with stroke.

RESULTS

We included 395 patients with acute stroke, with a mean age of 63.89 ± 13.42 years, of whom 340 (86.1%) had ischemic stroke, and 55 (13.9%) had hemorrhagic stroke. Out of 395, 113 (28.6%) had SAP and 282 (71.4%) did not, and the SII level in the SAP group was higher than that of the non-SAP group (p < .05). Logistic regression analysis of patients with stroke showed that higher SII was a risk factor for SAP in patients with stroke (per 100 units, HR = 1.081, 95% CI: 1.035-1.130, p < .001), and tertile grouping of SII showed that the risk of SAP was 5.059 times higher in the SIIQ3 group than in the SIIQ1 group (95% CI: 2.061-12.418, p < .001). ROC curve analysis indicated that the SII index had predictive value for the occurrence of SAP in patients with stroke, with an area under the curve of 0.752 (95% CI: 0.698-0.806). When the cutoff value was 861.01, the SII predicted SAP in patients with stroke with a sensitivity of 61.9% and a specificity of 76.2%.

CONCLUSION

Higher SII is an independent risk factor for the development of SAP in patients with stroke and has some predictive value for the development of SAP.

Neuroendocrine regulation in stroke

The neuroendocrine system, a crosstalk between the central nervous system and endocrine glands, balances and controls hormone secretion and their functions. Neuroendocrine pathways and mechanisms often get dysregulated following stroke, leading to altered hormone secretion and aberrant receptor expression. Dysregulation of the hypothalamus-pituitary-thyroid (HPT) axis and hypothalamus-pituitary-adrenal (HPA) axis often led to severe stroke outcomes. Post-stroke complications such as cognitive impairment, depression, infection etc. are directly or indirectly influenced by the altered neuroendocrine activity that plays a crucial role in stroke vulnerability and susceptibility. Therefore, it is imperative to explore various neurohormonal inter-relationships in regulating stroke, its outcome, and prognosis. Here, we review the biology of different hormones associated with stroke and explore their regulation with a view towards prospective therapeutics.

Augmented Renal Clearance in Patients with Acute Ischemic Stroke: A Prospective Observational Study

BACKGROUND

Augmented renal clearance (ARC) is a phenomenon that has been demonstrated in many subsets of critically ill patients and is characterized by a creatinine clearance (CrCl) > 130 mL/min. Prior research has examined ARC prevalence in the presence of sepsis, traumatic brain injury, subarachnoid hemorrhage, and intracranial hemorrhage. However, to our knowledge, no studies have examined whether this phenomenon occurs in patients suffering from an acute ischemic stroke (AIS). The objective of this study was to evaluate whether patients experiencing an AIS exhibit ARC, identify potential contributing factors, and examine the precision of current renal clearance estimation methods in patients with AIS experiencing ARC.

METHODS

This was a single-center prospective observational study conducted in adult patients admitted to a neurocritical intensive care unit (ICU) at a community hospital. Once consent was gained, patients with an admitting diagnosis of an AIS underwent a 24-h urine collection to assess measured CrCl. The primary end point assessed for ARC, defined as a measured CrCl > 130 mL/min. The secondary end point evaluated length of stay in the neurocritical ICU.

RESULTS

Twenty-eight patients met enrollment criteria, and data was analyzed for 20 patients. ARC was present in 35% of enrolled patients. Mathematical estimations of renal function were inadequate in detecting ARC manifestation. Patients experiencing ARC were associated with nonsignificantly shorter ICU length of stay.

CONCLUSIONS

ARC appears to manifest in patients with AIS inconsistently. Patients experiencing ARC were associated with nonsignificantly shorter ICU length of stay.

Effect of mean heart rate on 30-day mortality in ischemic stroke with atrial fibrillation: Data from the MIMIC-IV database

Background

The relationship of mean heart rate (MHR) with 30-day mortality in ischemic stroke patients with atrial fibrillation in the intensive care unit (ICU) remains unknown. This study aimed to investigate the association between MHR within 24 h of admission to the ICU and 30-day mortality among patients with atrial fibrillation and ischemic stroke.

Methods

This retrospective cohort study used data on US adults from the Medical Information Mart for Intensive Care-IV (MIMIC-IV, version 1.0) database. Patients with ischemic stroke who had atrial fibrillation for and first time in ICU admission were identified from the MIMIC-IV database. We used multivariable Cox regression models, a restricted cubic spline model, and a two-piecewise Cox regression model to show the effect of the MHR within 24 h of ICU admission on 30-day mortality.

Results

A total of 1403 patients with ischemic stroke and atrial fibrillation (mean [SD] age, 75.9 [11.4] years; mean [SD] heart rate, 83.8[16.1] bpm; 743 [53.0%] females) were included. A total of 212 (15.1%) patients died within 30 days after ICU admission. When MHR was assessed in tertials according to the 25th and 50th percentiles, the risk of 30-day mortality was higher in participants in group 1 (&lt; 72 bpm; adjusted hazard ratio, 1.23; 95% CI, 0.79–1.91) and group 3 (≥82 bpm; adjusted hazard ratio, 1.77; 95% CI, 1.23–2.57) compared with those in group 2 (72–82 bpm). Consistently in the threshold analysis, for every 1-bpm increase in MHR, there was a 2.4% increase in 30-day mortality (adjusted HR, 1.024; 95% CI, 1.01–1.039) in those with MHR above 80 bpm. Based on these results, there was a J-shaped association between MHR and 30-day mortality in ischemic stroke patients with atrial fibrillation admitted to the ICU, with an inflection point at 80 bpm of MHR.

Conclusion

In this retrospective cohort study, MHR within 24 h of admission was associated with 30-day mortality (nonlinear, J-shaped association) in patients with ischemic stroke and atrial fibrillation in the ICU, with an inflection point at about 80 bpm and a minimal risk observed at 72 to 81 bpm of MHR. This association was worthy of further investigation. If further confirmed, this association may provide a theoretical basis for formulating the target strategy of heart rate therapy for these patients.

Systemic immune responses after ischemic stroke: From the center to the periphery

Ischemic stroke is a leading cause of disability and death. It imposes a heavy economic burden on individuals, families and society. The mortality rate of ischemic stroke has decreased with the help of thrombolytic drug therapy and intravascular intervention. However, the nerve damage caused by ischemia-reperfusion is long-lasting and followed by multiple organ dysfunction. In this process, the immune responses manifested by systemic inflammatory responses play an important role. It begins with neuroinflammation following ischemic stroke. The large number of inflammatory cells released after activation of immune cells in the lesion area, along with the deactivated neuroendocrine and autonomic nervous systems, link the center with the periphery. With the activation of systemic immunity and the emergence of immunosuppression, peripheral organs become the second “battlefield” of the immune response after ischemic stroke and gradually become dysfunctional and lead to an adverse prognosis. The purpose of this review was to describe the systemic immune responses after ischemic stroke. We hope to provide new ideas for future research and clinical treatments to improve patient outcomes and quality of life.

Longitudinal changes in the hypothalamic–pituitary–adrenal axis and sympathetic nervous system are related to the prognosis of stroke

Background and purpose

This study sought to improve methods to identify biomarkers in the neuroendocrine system related to stroke progression to improve the accuracy of traditional tools for evaluating stroke prognosis.

Methods

Seventy-four stroke patients and 237 healthy controls were prospectively included. We measured urinary epinephrine (E), noradrenaline (NE), dopamine (DA) and cortisol (F) on days 1, 3, and 5 after stroke onset and plasma F, adrenocorticotropic hormone (ACTH), thyrotropin (TSH), prolactin (PRL), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and growth hormone (GH). The correlation between these hormone levels and 90-day prognosis was analyzed, their value in assessing prognosis was compared with lesion volume and National Institutes of Health Stroke Scale (NIHSS) scores using receiver operating characteristic (ROC) curves, and their correlation with conventional clinical variables was assessed.

Results

Levels of F, 24-h urinary free cortisol(UFC), E, NE, DA, and GH on days 1, 3, and 5 were significantly higher in stroke patients than in controls (P &lt; 0.01), while ACTH and TSH decreased, gradually approaching normal within 5 days of onset. Levels of E, NE, F, and 24-h UFC were proportional to severity, and all gradually decreased within 5 days of onset in patients with a good prognosis and gradually increased or remained high in those with a poor prognosis. After adjustment for age, sex, NIHSS, or Glasgow Coma Scale (GCS) score, F &gt; 13.6 μg/dL, ACTH &gt; 22.02 pg/mL and NE &gt; 123.5 μg/ 24 h were identified as risk factors for a poor prognosis 90 days after stroke (P &lt; 0.05). The combination of F, ACTH, NE, white blood cell count (WBC), glucose (Glu), and hemoglobin (Hb) was significantly more accurate than lesion volume (AUC: 0.931 vs. 0.694 P = 0.019) and NIHSS score (AUC: 0.931 vs. 0.746 P = 0.034) in predicting poor prognosis of stroke 1 day after onset. Hormones and traditional clinical variables were correlated to varying degrees, with NE correlating most strongly with 24-h UFC (r = 0.54) and moderately positively with lesion volume (r = 0.40) and NIHSS score (r = 0.45).

Conclusions

Stroke causes significant time-phased dynamic changes in the hypothalamic–pituitary–adrenal axis and sympathetic nervous system, and plasma F, ACTH, and urinary NE levels can be used to assess stroke severity and prognosis.

Chinese clinical trial registry

Registration Number: ChiCTR1900024992. Registration Date: 2019/8/6.

The etiology of poststroke-depression: a hypothesis involving HPA axis

Approximately, one in three ischemic stroke survivors suffered from depression, namely, post-stroke depression (PSD). PSD affects functional rehabilitation and may lead to poor quality of life of patients. There are numerous explanations about the etiologies of PSD. Here, we speculated that PSD are likely to be the result of specific changes in brain pathology. We hypothesized that the stroke-induced hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis plays an important role in PSD. Stroke initiates a complex sequence of events in neuroendocrine system including HPA axis. The HPA axis is involved in the pathophysiology of depression, especially, the overactivity of the HPA axis occurs in major depressive disorder. This review summarizes the possible etiologies of PSD, focusing on the stroke-induced activation of HPA axis, mainly including the stress followed by severe brain damage and the proinflammatory cytokines release. The role of hyperactive of HPA axis in PSD was discussed in detail, which includes the role of high level corticotropin-releasing hormone in PSD, the effects of glucocorticoids on the alterations in specific brain structures, the expression of enzymes, excitotoxicity, the change in intestinal permeability, and the activation of microglia. The relationship between neuroendocrine regulation and inflammation was also described. Finally, the therapy of PSD by regulating HPA axis, neuroendocrine, and immunity was discussed briefly. Nevertheless, the change of HPA axis and the occurring of PSD maybe interact and promote on each other, and future investigations should explore this hypothesis in more depth.

Heart rate variability as an autonomic biomarker in ischemic stroke

Stroke is one of the leading causes of mortality and disability worldwide. Autonomic dysfunction after ischemic stroke is frequently associated with cardiac complications and high mortality. The brain-heart axis is a good model for understanding autonomic interaction between the autonomic central network and the cardiovascular system. Heart rate variability (HRV) analysis is a non-invasive approach for understanding cardiac autonomic regulation. In stroke patients, HRV parameters are altered in the acute and chronic stages of the disease, having a prognostic value. In this literature review we summarize the main concepts about the autonomic nervous system and HRV as autonomic biomarkers in ischemic stroke.

Endocrine Dysfunction Following Stroke

Endocrine dysfunction is known to occur after traumatic brain injury. The purpose of this study was to examine the incidence of various endocrine dysfunctions after a stroke. The Taiwan National Health Insurance Research Database (NHIRD) was searched from 2001 to 2011 for patients with a diagnosis of stroke. Stroke patients were matched by diagnosis date, age, and sex to patients without a stroke. Cox proportional hazards regression analyses were performed to compare the incidence of goiter, acquired hypothyroidism, thyroiditis, pituitary dysfunction, and disorders of the adrenal glands between stroke and non-stroke patients. There were 131,951 patients in the stroke group, and 131,951 in the matched non- stroke group (mean age 66.1 ± 14.9 years). Stroke patients had significantly higher risk of acquired hypothyroidism (crude hazard ratio [cHR] = 1.65, 95% confidence interval [CI]: 1.44, 1.90; adjusted hazard ratio [aHR] = 1.65, 95% CI: 1.42, 1.91), pituitary dysfunction (cHR = 2.32, 95% CI: 1.79, 2.99; aHR = 1.92, 95% CI: 1.46, 2.52), and disorders of the adrenal glands (cHR = 1.79, 95% CI: 1.52, 2.12; aHR =1.62, 95% CI: 1.36, 1.92) than non-stroke patients. Pituitary dysfunction and disorders of the adrenal glands were found in both hemorrhagic stroke and ischemic stroke patients, while hypothyroidism was seen in ischemic stroke patients only. No significant association was found for goiter and thyroiditis. In conclusions, stroke survivors have an approximately 2-fold increased risk of developing acquired hypothyroidism, pituitary dysfunction, or disorders of the adrenal glands. These risks should be taken into account in the management of patients who have ischemic or hemorrhagic strokes. Graphical Abstract.

Eriocitrin alleviates oxidative stress and inflammatory response in cerebral ischemia reperfusion rats by regulating phosphorylation levels of Nrf2/NQO-1/HO-1/NF-κB p65 proteins

Background

Cerebral ischemia (CI) can lead to ischemic stroke. The most effective therapy for cerebral ischemic stroke is the early restoration of blood reperfusion. However, reperfusion after CI can result in cerebral ischemia reperfusion (CI/R) injury. This study aimed to detect the effect of eriocitrin on cerebral I/R injury and investigate the underlying mechanism.

Methods

Seventy male Sprague-Dawley (SD) rats were randomly divided into 5 groups: the control group, the cerebral I/R group, the I/R + eriocitrin 8 mg/kg group, the I/R + eriocitrin 16 mg/kg group, and the I/R + eriocitrin 32 mg/kg group. Different doses of eriocitrin or 0.5% carboxymethyl cellulose sodium were administrated to the rats once daily for 7 days before middle cerebral artery occlusion (MCAO). PCR staining was performed to observe cerebral infarction. Hematoxylin and eosin (H&E) staining was carried out to observe the damage to the brain tissue. Terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) was used to detect apoptosis. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the relative mRNA levels of related molecules. Western blot was used to detect the expression of related proteins. The detection kits were used to detect superoxide dismutase (SOD) and lactic dehydrogenase (LDH) activity, and malondialdehyde (MDA) content respectively. Enzyme-linked immunosorbent assay (ELISA) was used to detect TNF-radiation, interleukin-6 (IL-6), and interleukin-10 (IL-10).

Results

The results showed that Eriocitrin significantly reduced the cerebral infarct volume, cerebral water content, and cerebral indexes. Eriocitrin treatment alleviated pathological injury, promoted cell proliferation, and inhibited cell apoptosis. Eriocitrin upregulated SOD activity and downregulated MDA and LDH content. Eriocitrin also effectively decreased the levels of IL-6 and tumor necrosis factor-α (TNF-α), but increased the content of IL-10 in serum and brain tissues. Furthermore, Eriocitrin increased the phosphorylation of nuclear factor erythroid 2-related factor (Nrf2), as well as the expressions of heme-oxygenase-1 (HO-1) and quinine oxidoreductase 1 (NQO1). Moreover, Eriocitrin decreased the phosphorylation of nuclear factor-κB (NF-κB) p65.

Conclusions

Our results indicated that Eriocitrin attenuated oxidative injury and inflammatory response in rats with CI/R via the Nrf2/HO-1/NQO1/NF-κB signaling pathway.

Impact of Key Nicotinic AChR Subunits on Post-Stroke Pneumococcal Pneumonia

Pneumonia is the most frequent severe medical complication after stroke. An overactivation of the cholinergic signaling after stroke contributes to immunosuppression and the development of spontaneous pneumonia caused by Gram-negative pathogens. The α7 nicotinic acetylcholine receptor (α7nAChR) has already been identified as an important mediator of the anti-inflammatory pathway after stroke. However, whether the α2, α5 and α9/10 nAChR expressed in the lung also play a role in suppression of pulmonary innate immunity after stroke is unknown. In the present study, we investigate the impact of various nAChRs on aspiration-induced pneumonia after stroke. Therefore, α2, α5, α7 and α9/10 nAChR knockout (KO) mice and wild type (WT) littermates were infected with Streptococcus pneumoniae (S. pneumoniae) three days after middle cerebral artery occlusion (MCAo). One day after infection pathogen clearance, cellularity in lung and spleen, cytokine secretion in bronchoalveolar lavage (BAL) and alveolar-capillary barrier were investigated. Here, we found that deficiency of various nAChRs does not contribute to an enhanced clearance of a Gram-positive pathogen causing post-stroke pneumonia in mice. In conclusion, these findings suggest that a single nAChR is not sufficient to mediate the impaired pulmonary defense against S. pneumoniae after experimental stroke.

The relationship between stress and Alzheimer's disease

Stress is critically involved in the development and progression of disease. From the stress of undergoing treatments to facing your own mortality, the physiological processes that stress drives have a serious detrimental effect on the ability to heal, cope and maintain a positive quality of life. This is becoming increasingly clear in the case of neurodegenerative diseases. Neurodegenerative diseases involve the devastating loss of cognitive and motor function which is stressful in itself, but can also disrupt neural circuits that mediate stress responses. Disrupting these circuits produces aberrant emotional and aggressive behavior that causes long-term care to be especially difficult. In addition, added stress drives progression of the disease and can exacerbate symptoms. In this review, I describe how neural and endocrine pathways activated by stress interact with ongoing neurodegenerative disease from both a clinical and experimental perspective.

Hypothalamic-pituitary-adrenocortical axis dysfunction in epilepsy

Epilepsy is a common neurological disease, affecting 2.4million people in the US. Among the many different forms of the disease, temporal lobe epilepsy (TLE) is one of the most frequent in adults. Recent studies indicate the presence of a hyperactive hypothalamopituitary- adrenocortical (HPA) axis and elevated levels of glucocorticoids in TLE patients. Moreover, in these patients, stress is a commonly reported trigger of seizures, and stress-related psychopathologies, including depression and anxiety, are highly prevalent. Elevated glucocorticoids have been implicated in the development of stress-related psychopathologies. Similarly, excess glucocorticoids have been found to increase neuronal excitability, epileptiform activity and seizure susceptibility. Thus, patients with TLE may generate abnormal stress responses that both facilitate ictal discharges and increase vulnerability for the development of comorbid psychopathologies. Here, we will examine the evidence that the HPA axis is disrupted in TLE, consider potential mechanisms by which this might occur, and discuss the implications of HPA dysfunction for seizuretriggering and psychiatric comorbidities.

[Post-stroke depression]

Cerebrovascular diseases are associated with a high incidence of psychiatric disorders. Depressive illness after stroke has been extensively investigated during the last three decades. Post-stroke depression is estimated to occur in 30-35% of the patients during the first year after stroke. Numerous studies have given information on its prevalence, pathogenesis, clinical course, treatment and prevention. Despite the high level of comorbidity, depressive symptoms appear to remain frequently unrecognized and untreated. This has a negative effect on the rehabilitation, quality of live, cognitive function and mortality of stroke patients.