Plasma cytokines in acute stroke

Role of CRF and the hypothalamic-pituitary-adrenal axis in stroke: revisiting temporal considerations and targeting a new generation of therapeutics

Ischaemic neurovascular stroke represents a leading cause of death in the developed world. Preclinical and human epidemiological evidence implicates the corticotropin-releasing factor (CRF) family of neuropeptides as mediators of acute neurovascular injury pathology. Preclinical investigations of the role of CRF, CRF receptors and CRF-dependent activation of the hypothalamic-pituitary-adrenal (HPA) axis have pointed toward a tissue-specific and temporal relationship between activation of these pathways and physiological outcomes. Based on the literature, the major phases of ischaemic stroke aetiology may be separated into an acute phase in which CRF and anti-inflammatory stress signalling are beneficial and a chronic phase in which these contribute to neural degeneration, toxicity and apoptotic signalling. Significant gaps in knowledge remain regarding the pathway, temporality and systemic impact of CRF signalling and stress biology in neurovascular injury progression. Heterogeneity among experimental designs poses a challenge to defining the apparent reciprocal relationship between neurological injury and stress metabolism. Despite these challenges, it is our opinion that the elucidated temporality may be best matched with an antibody against CRF with a half-life of days to weeks as opposed to minutes to hours as with small-molecule CRF receptor antagonists. This state-of-the-art review will take a multipronged approach to explore the expected potential benefit of a CRF antibody by modulating CRF and corticotropin-releasing factor receptor 1 signalling, glucocorticoids and autonomic nervous system activity. Additionally, this review compares the modulation of CRF and HPA axis activity in neuropsychiatric diseases and their counterpart outcomes post-stroke and assess lessons learned from antibody therapies in neurodegenerative diseases.

Dynamics of inflammatory factors expression in ischemic brain tissue injury

Ischemic stroke is one of the most common cause of mortality and disability in the modern world. Still, therapeutic options remain modest. Aim of the study was to present dynamics of inflammatory factors expression (C reactive protein, procalcitonin, interleukin 10) in patients after ischemic stroke. Our study included 101 patients divided in thrombolised and nonthrombolised groups. Inflammatory factors concentration in serum was determinate at admission, 24, 48 hours and seven days after the initial onset, while neurological assessment was measured at the admission, 24 hours, seven days and three months after the initial onset using National Institute of Health Stroke Scale and Rankin Scale. Certain pattern was observed in dynamics of inflammatory factors: intensive increase in first and second day after the stroke, followed by decrease till day seven in both groups. Additionally, thrombolised group showed significant neurological improvement. Although well investigated, the role of inflammatory factors in the ischemic stroke still stays controversial. High association of C reactive protein and interleukin 10 values suggest potential prognostic role in patient’s follow-up, while the role of procalcitonin values still remains unclear.

Genetic variation within the interleukin-1 gene cluster and ischemic stroke

BACKGROUND AND PURPOSE

Evidence is emerging that inflammation plays a key role in the pathophysiology of ischemic stroke (IS). The aim of this study was to investigate whether genetic variation in the interleukin-1α, interleukin-1β, and interleukin-1 receptor antagonist genes (IL1A, IL1B, and IL1RN) is associated with IS and/or any etiologic subtype of IS.

METHODS

Twelve tagSNPs were analyzed in the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), which comprises 844 patients with IS and 668 control subjects. IS subtypes were defined according to the Trial of Org 10172 in Acute Stroke Treatment criteria in SAHLSIS. The Lund Stroke Register and the Malmö Diet and Cancer study were used as a replication sample for overall IS (in total 3145 patients and 1793 control subjects).

RESULTS

The single nucleotide polymorphism rs380092 in IL1RN showed an association with overall IS in SAHLSIS (OR, 1.21; 95% CI, 1.02-1.43; P=0.03), which was replicated in the Lund Stroke Register and the Malmö Diet and Cancer study sample. An association was also detected in all samples combined (OR, 1.12; 95% CI, 1.04-1.21; P=0.03). Three single nucleotide polymorphisms in IL1RN (including rs380092) were nominally associated with the subtype of cryptogenic stroke in SAHLSIS, but the statistical significance did not remain after correction for multiple testing. Furthermore, increased plasma levels of interleukin-1 receptor antagonist were observed in the subtype of cryptogenic stroke compared with controls.

CONCLUSIONS

This comprehensive study, based on a tagSNP approach and replication, presents support for the role of IL1RN in overall IS.

Post-stroke infection: a role for IL-1ra?

BACKGROUND

Infection is common following stroke and is independently associated with worse outcome. Clinical studies suggest that infections occur more frequently in those individuals with stroke-induced immunologic dysfunction. This study sought to explore the contribution of immunomodulatory cytokines and hormones to lymphocyte function and infection risk.

METHODS

Patients (N = 112) were enrolled as soon as possible after the onset of ischemic stroke. Blood was drawn to assess plasma cortisol, IL-10, IL-1ra, lymphocyte numbers, and lymphocyte function at 72 h after stroke onset; infections were censored through 21 days after stroke onset.

RESULTS

Infection occurred in 25% of patients. Stroke severity was the most important predictor of infection risk. Increased plasma cortisol, IL-10, and IL-1ra, as well as decreased lymphocyte numbers, at 72 h after stroke onset were associated with risk of subsequent infection. After controlling for stroke severity, only IL-1ra was independently associated with infection risk, and the degree of risk was consistent throughout the post-stroke period. Infection, but not IL-1ra itself, was associated with worse outcome at 3 months.

CONCLUSIONS

In this study cohort, increased plasma IL-1ra was independently associated with the risk of post-stroke infection. Further studies are needed to validate this finding, which could have important implications for stroke therapy.

The effect of C-reactive protein on functional outcome in ischemic stroke patients

This study was performed to evaluate the effect of C-reactive protein (CRP) measured within 24 hr after stroke onset on functional outcome in ischemic stroke patients. The medical records of 28 first-ever hemiplegic ischemic stroke patients with the lesions on the middle cerebral arterial territory were reviewed. Subjects were classified into experimental group (serum CRP >or= 0.5 mg/dL) and control group (serum CRP<0.5 mg/dL) based on the level of serum CRP measured within 24 hr after stroke onset. Serum CRP measured within 24 hr after stroke onset was significantly correlated with functional scales in ischemic stroke patients.

C-reactive protein and white blood cell count increases in the first 24 hours after acute stroke

Levels of C-reactive protein (CRP) and white blood cell count (WBC) in acute stroke may reflect the stroke lesion itself or pre-existing factors such as infections, smoking or atherosclerosis. The aim of this study was to investigate the relation between CRP and WBC levels and time from onset of stroke, stroke severity and outcome.

PATIENTS AND METHODS

The analyses were based on 719 patients in whom WBC test material was obtained within 9 h of stroke onset and CRP test material within 24 h of stroke onset. Stroke severity was assessed by the Scandinavian Stroke Scale Score on admission and outcome by death 7 days, 3 months and 1 year after symptom onset as well as modified Rankin Scale 3 months after stroke onset.

RESULTS

CRP and WBC levels correlated significantly with time from symptom onset as well as with stroke severity and outcome. Levels of CRP and WBC were higher in later determinations in severe stroke. In multivariate logistic regression analysis, CRP(+10 mg/l) was independently related to 1-year mortality (OR 1.1, 95% CI 1.02-1.2).

CONCLUSION

Levels of WBC and CRP increase within the first 24 h in patients with severe stroke. CRP but not WBC is related to long-term mortality possibly by reflecting the vascular risk profile.

Serum cardiac troponin I in acute stroke is related to serum cortisol and TNF-alpha

BACKGROUND

Serum cardiac troponin I (cTnI) is a specific marker of myocardial injury related to in-patient fatality and cardiac injury in acute stroke. We investigated whether cTnI in acute stroke is related to serum cortisol, acute inflammatory response, and insular damage. We also investigated whether cTnI predicted outcome at 3 months.

PATIENTS AND METHODS

The study was based on 155 patients with CT-confirmed acute cerebral infarction and study inclusion within 24 h (50% within 12 h) of stroke onset. Blood samples were obtained on inclusion. Stroke severity was assessed by the Scandinavian Stroke Scale (SSS) and outcome was assessed by the modified Rankin Scale (mRS), death or dependency was defined as mRS > or =3 three months after stroke.

RESULTS

35% of all patients and 63% of patients who died within 3 months were troponin positive. Tumor necrosis factor-alpha (TNF-alpha) and cortisol were independently related to detection of cTnI: TNF-alpha(+100 pg/ml) OR 1.5 (CI 95% 1.1-2.2), cortisol(+100 nmol/l) OR 1.1 (CI 95% 1.01-1.2). SSS and age were also included in this model and did not reach significance. cTnI positivity was, together with age, stroke severity and prestroke mRS, but not s-cortisol, an independent explanatory variable of outcome at 3 months (death or dependency) with OR 4.1 (CI 95% 1.1-14.5). cTnI did not relate to insular involvement.

CONCLUSION

In this study, cortisol and TNF-alpha were independently related to cTnI, which was predictive of 3-month prognosis.

Serum-cortisol reflects severity and mortality in acute stroke

BACKGROUND

The adrenal glucocorticoid stress response in humans causes catabolism, increasing blood glucose and heart rate, and possibly potentiates ischaemic damage to neurons. These effects could induce secondary brain damage in acute stroke.

MATERIALS AND METHODS

This prospective study was based on a single determination of s-cortisol in 172 patients included within 24 h of stroke onset, 50% within 12 h of stroke onset. All patients were admitted to hospital within 6 h of stroke onset. We investigated the relations of s-cortisol to neurological deficit measured by Scandinavian Stroke Scale (SSS), lesion volume on CT-scan, blood glucose on admission, pulse rate, blood pressure, body temperature, deteriorating stroke, cytokines and cytokine receptors, and outcome.

RESULTS

In a multivariate logistic regression analysis, s-cortisol was independently related to death within 7 days of stroke onset, odds ratio (OR) Cortisol(+100 nmol/l) 1.9 (95% CI 1.01-3.8); serum-cortisol was, however, not a predictor of death or dependency within 3 months. S-cortisol correlated to SSS (rho=-0.45, p<0.001), body temperature (rho=0.27, p<0.001), pulse rate (rho=0.26, p<0.001), and lesion volume (rho=0.33, p<0.001). S-cortisol was related to the presence of insular damage.

CONCLUSION

Acute stroke mortality related to increasing serum-cortisol levels. S-cortisol was associated with stroke severity and markers reflecting stroke severity.

Deteriorating ischaemic stroke. cytokines, soluble cytokine receptors, ferritin, systemic blood pressure, body temperature, blood glucose, diabetes, stroke severity, and CT infarction-volume as predictors of deteriorating ischaemic stroke

BACKGROUND AND PURPOSE

Although the causes of neurological deterioration in acute cerebral infarction have not yet been identified, many variables have been associated with deterioration. The aim of this study was to investigate deteriorating ischaemic stroke.

METHODS

Deterioration was defined as a decrease in Scandinavian Stroke Scale (SSS) of at least 2 points occurring within 72 h of stroke onset and lasting at least 6 h. The earlier found associations between neurological deterioration and systemic blood pressure, blood glucose, body temperature, stroke severity, and diabetes were investigated in a population of 896 consecutive patients with acute cerebral infarction. In a substudy of 162 of these patients, we evaluated the relations of neurological deterioration to s-ferritin, p-tumor necrosis factor-alpha, p-interleukin-1beta, p-interleukin-1 receptor antagonist, p-interleukin-6, p-interleukin-10, and p-soluble tumor necrosis factor receptors 1 and 2.

RESULTS

Patients with neurological deterioration had more severe strokes than nondeteriorating patients: median SSS on admission 31 versus 40, p<0.001, Mann-Whitney. We could not confirm previous reports of an association of deteriorating stroke with blood pressure, blood glucose, body temperature, diabetes, s-ferritin or cytokines.

CONCLUSIONS

Severe stroke was a predictor of neurological deterioration. This study did not confirm other reported predictors of deterioration.