What is the impact of acute endocrine and metabolic alterations on long-term ischemic stroke prognosis: a prospective study

BACKGROUND

Post-stroke stress can trigger instant survival but its influence on long-term ischemic stroke outcomes remains controversial. Thus, we sought to explore the associations of acute post-stroke stress evidenced by endocrine and metabolic changes, with long-term ischemic stroke outcomes.

METHODS

Admissions for acute ischemic stroke within seven days of onset were prospectively recruited to determine acute endocrine and metabolic variations measured by thyroid parameters and the stress hyperglycemia ratio (SHR). Long-term ischemic stroke prognoses were followed up for one year, with the primary outcome being a modified Rankin Scale score of 3 to 6.

RESULTS

A total of 887 patients were enrolled, of which 535 reached the final one-year followed up at a poor prognosis rate of 29.3%. Patients with poor outcomes were observed to have lower levels of free triiodothyronine (fT3) and higher levels of SHR on admission. Medium values (fT3, 4.4 mmol/L; SHR, 8 nmol/L) were used to divide patients into four gradient stress degrees. Larger acute endocrine and metabolic variations (fT3 < 4.4 mmol/L and SHR ≥ 8 nmol/L) were independently associated with a poor one-year prognosis (adjusted OR = 4.231, P = 0.001).

CONCLUSIONS

High degrees of acute post-stroke stress may aggravate long-term ischemic stroke prognosis and timely stress-reduced interventions may help promote post-stroke living quality is equally important as survival.

Machine learning using multimodal and autonomic nervous system parameters predicts clinically apparent stroke-associated pneumonia in a development and testing study

BACKGROUND

Stroke-associated pneumonia (SAP) is a preventable determinant for poor outcome after stroke. Machine learning (ML) using large-scale clinical data warehouses may be able to predict SAP and identify patients for targeted interventions. The aim of this study was to develop a prediction model for identifying clinically apparent SAP using automated ML.

METHODS

The ML model used clinical and laboratory parameters along with heart rate (HR), heart rate variability (HRV), and blood pressure (BP) values obtained during the first 48 h after stroke unit admission. A logistic regression classifier was developed and internally validated with a nested-cross-validation (nCV) approach. For every shuffle, the model was first trained and validated with a fixed threshold for 0.9 sensitivity, then finally tested on the out-of-sample data and benchmarked against a widely validated clinical score (A2DS2).

RESULTS

We identified 2390 eligible patients admitted to two-stroke units at Charité between October 2020 and June 2023, of whom 1755 had all parameters available. SAP was diagnosed in 96/1755 (5.5%). Circadian profiles in HR, HRV, and BP metrics during the first 48 h after admission exhibited distinct differences between patients with SAP diagnosis vs. those without. CRP, mRS at admission, leukocyte count, high-frequency power in HRV, stroke severity at admission, sex, and diastolic BP were identified as the most informative ML features. We obtained an AUC of 0.91 (CI 0.88-0.95) for the ML model on the out-of-sample data in comparison to an AUC of 0.84 (CI 0.76-0.91) for the previously established A2DS2 score (p < 0.001). The ML model provided a sensitivity of 0.87 (CI 0.75-0.97) with a corresponding specificity of 0.82 (CI 0.78-0.85) which outperformed the A2DS2 score for multiple cutoffs.

CONCLUSIONS

Automated, data warehouse-based prediction of clinically apparent SAP in the stroke unit setting is feasible, benefits from the inclusion of vital signs, and could be useful for identifying high-risk patients or prophylactic pneumonia management in clinical routine.

Systemic innate myeloid responses to acute ischaemic and haemorrhagic stroke

Acute ischaemic and haemorrhagic stroke account for significant disability and morbidity burdens worldwide. The myeloid arm of the peripheral innate immune system is critical in the immunological response to acute ischaemic and haemorrhagic stroke. Neutrophils, monocytes, and dendritic cells (DC) contribute to the evolution of pathogenic local and systemic inflammation, whilst maintaining a critical role in ongoing immunity protecting against secondary infections. This review aims to summarise the key alterations to myeloid immunity in acute ischaemic stroke, intracerebral haemorrhage (ICH), and subarachnoid haemorrhage (SAH). By integrating clinical and preclinical research, we discover how myeloid immunity is affected across multiple organ systems including the brain, blood, bone marrow, spleen, and lung, and evaluate how these perturbations associate with real-world outcomes including infection. These findings are placed in the context of the rapidly developing field of human immunology, which offers a wealth of opportunity for further research.

The Role of Arginine-Vasopressin in Stroke and the Potential Use of Arginine-Vasopressin Type 1 Receptor Antagonists in Stroke Therapy: A Narrative Review

Stroke is a life-threatening condition in which accurate diagnoses and timely treatment are critical for successful neurological recovery. The current acute treatment strategies, particularly non-invasive interventions, are limited, thus urging the need for novel therapeutical targets. Arginine vasopressin (AVP) receptor antagonists are emerging as potential targets to treat edema formation and subsequent elevation in intracranial pressure, both significant causes of mortality in acute stroke. Here, we summarize the current knowledge on the mechanisms leading to AVP hyperexcretion in acute stroke and the subsequent secondary neuropathological responses. Furthermore, we discuss the work supporting the predictive value of measuring copeptin, a surrogate marker of AVP in stroke patients, followed by a review of the experimental evidence suggesting AVP receptor antagonists in stroke therapy. As we highlight throughout the narrative, critical gaps in the literature exist and indicate the need for further research to understand better AVP mechanisms in stroke. Likewise, there are advantages and limitations in using copeptin as a prognostic tool, and the translation of findings from experimental animal models to clinical settings has its challenges. Still, monitoring AVP levels and using AVP receptor antagonists as an add-on therapeutic intervention are potential promises in clinical applications to alleviate stroke neurological consequences.

A hyperacute immune map of ischaemic stroke patients reveals alterations to circulating innate and adaptive cells

Systemic immune changes following ischaemic stroke are associated with increased susceptibility to infection and poor patient outcome due to their role in exacerbating the ischaemic injury and long-term disability. Alterations to the abundance or function of almost all components of the immune system post-stroke have been identified, including lymphocytes, monocytes and granulocytes. However, subsequent infections have often confounded the identification of stroke-specific effects. Global understanding of very early changes to systemic immunity is critical to identify immune targets to improve clinical outcome. To this end, we performed a small, prospective, observational study in stroke patients with immunophenotyping at a hyperacute time point (< 3 h) to explore early changes to circulating immune cells. We report, for the first time, decreased frequencies of type 1 conventional dendritic cells (cDC1), haematopoietic stem and progenitor cells (HSPCs), unswitched memory B cells and terminally differentiated effector memory T cells re-expressing CD45RA (TEMRA). We also observed concomitant alterations to human leucocyte antigen D-related (HLA-DR), CD64 and CD14 expression in distinct myeloid subsets and a rapid activation of CD4+ T cells based on CD69 expression. The CD69+ CD4+ T cell phenotype inversely correlated with stroke severity and was associated with naive and central memory T (TCM) cells. Our findings highlight early changes in both the innate and adaptive immune compartments for further investigation as they could have implications the development of post-stroke infection and poorer patient outcomes.

The role of brain barriers in the neurokinetics and pharmacodynamics of lithium

Lithium (Li) is the most widely used mood stabilizer in treating patients with bipolar disorder. However, more than half of the patients do not or partially respond to Li therapy, despite serum Li concentrations in the serum therapeutic range. The exact mechanisms underlying the pharmacokinetic-pharmacodynamic (PK-PD) relationships of lithium are still poorly understood and alteration in the brain pharmacokinetics of lithium may be one of the mechanisms explaining the variability in the clinical response to Li. Brain barriers such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) play a crucial role in controlling blood-to-brain and brain-to-blood exchanges of various molecules including central nervous system (CNS) drugs. Recent in vivo studies by nuclear resonance spectroscopy revealed heterogenous brain distribution of Li in human that were not always correlated with serum concentrations, suggesting regional and variable transport mechanisms of Li through the brain barriers. Moreover, alteration in the functionality and integrity of brain barriers is reported in various CNS diseases, as a cause or a consequence and in this regard, Li by itself is known to modulate BBB properties such as the expression and activity of various transporters, metabolizing enzymes, and the specialized tight junction proteins on BBB. In this review, we will focus on recent knowledge into the role of the brain barriers as key-element in the Li neuropharmacokinetics which might improve the understanding of PK-PD of Li and its interindividual variability in drug response.

Inflammatory and stress markers predicting pneumonia, outcome, and etiology in patients with stroke: Biomarkers for predicting pneumonia, functional outcome, and death after stroke

Objective

Prognosis of stroke is negatively affected by complications, in particular stroke-associated pneumonia (SAP). We hypothesized that inflammatory and stress biomarkers predict SAP during hospitalization and outcome 3 months after stroke.

Methods

We pooled the clinical data of 2 acute stroke studies with identical assessment: the STRoke Adverse outcome is associated WIth NoSoKomial Infections (STRAWINSKI) and PREDICT studies. Measurement of biomarkers (ultrasensitive procalcitonin [PCTus]; midregional pro-adrenomedullin; midregional pro-atrial natriuretic peptide [MRproANP]; ultrasensitive copeptin [CPus]; C-terminal pro-endothelin) was performed from serum samples drawn on the first 4 days of hospital admission.

Results

The combined cohort consists of 573 cases with available backup samples to perform the analysis. SAP was associated with increased admission and maximum levels of all biomarkers. Furthermore, all biomarkers were associated with death and correlated with functional outcome 3 months after stroke. The multivariate logistic regression model retained ultrasensitive CPus and PCTus beyond clinical risk factors for predicting SAP, improving the receiver operating characteristic area under the curve (AUC) from 0.837 to 0.876. In contrast, the biomarkers did not improve the prediction of death and functional outcome in the multivariate model. Cardioembolic strokes were significantly associated with higher values of all biomarkers, whereas discrimination was best for MRproANP (AUC = 0.811 for maximum value).

Conclusions

The tested biomarkers are associated with SAP and poor functional outcome. However, these biomarkers only slightly improve prediction of SAP and do not improve long-term outcome prediction over clinical parameters. MRproANP showed the best discrimination for identifying cardioembolic stroke, warranting further studies to confirm our finding.

Clinical trial registration

clinicaltrials.gov NCT01264549 and NCT01079728.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG).

METHODS

This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured.

DISCUSSION

The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Biomarkers of immune capacity, infection and inflammation are associated with poor outcome and mortality after stroke - the PREDICT study

Background

Almost 40% of stroke patients have a poor outcome at 3 months after the index event. Predictors for stroke outcome in the early acute phase may help to tailor stroke treatment. Infection and inflammation are considered to influence stroke outcome.

Methods

In a prospective multicenter study in Germany and Spain, including 486 patients with acute ischemic stroke, we used multivariable regression analysis to investigate the association of poor outcome with monocytic HLA-DR (mHLA-DR) expression, interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-alpha) and lipopolysaccharide-binding protein (LBP) as markers for immunodepression, inflammation and infection. Outcome was assessed at 3 months after stroke via a structured telephone interview using the modified Rankin Scale (mRS). Poor outcome was defined as a mRS score of 3 or higher which included death. Furthermore, a time-to-event analysis for death within 3 months was performed.

Results

Three-month outcome data was available for 391 patients. Female sex, older age, diabetes mellitus, atrial fibrillation, stroke-associated pneumonia (SAP) and higher National Institute of Health Stroke Scale (NIHSS) score as well as lower mHLA-DR levels, higher IL-6 and LBP-levels at day 1 were associated with poor outcome at 3 months in bivariate analysis. Furthermore, multivariable analysis revealed that lower mHLA-DR expression was associated with poor outcome.

Female sex, older age, atrial fibrillation, SAP, higher NIHSS score, lower mHLA-DR expression and higher IL-6 levels were associated with shorter survival time in bivariate analysis. In multivariable analysis, SAP and higher IL-6 levels on day 1 were associated with shorter survival time.

Conclusions

SAP, lower mHLA-DR-expression and higher IL-6 levels on day one are associated with poor outcome and shorter survival time at 3 months after stroke onset.

Trial registration

www.clinicaltrials.gov, NCT01079728, March 3, 2010.

The spleen may be an important target of stem cell therapy for stroke

Stroke is the most common cerebrovascular disease, the second leading cause of death behind heart disease and is a major cause of long-term disability worldwide. Currently, systemic immunomodulatory therapy based on intravenous cells is attracting attention. The immune response to acute stroke is a major factor in cerebral ischaemia (CI) pathobiology and outcomes. Over the past decade, the significant contribution of the spleen to ischaemic stroke has gained considerable attention in stroke research. The changes in the spleen after stroke are mainly reflected in morphology, immune cells and cytokines, and these changes are closely related to the stroke outcomes. Autonomic nervous system (ANS) activation, release of central nervous system (CNS) antigens and chemokine/chemokine receptor interactions have been documented to be essential for efficient brain-spleen cross-talk after stroke. In various experimental models, human umbilical cord blood cells (hUCBs), haematopoietic stem cells (HSCs), bone marrow stem cells (BMSCs), human amnion epithelial cells (hAECs), neural stem cells (NSCs) and multipotent adult progenitor cells (MAPCs) have been shown to reduce the neurological damage caused by stroke. The different effects of these cell types on the interleukin (IL)-10, interferon (IFN), and cholinergic anti-inflammatory pathways in the spleen after stroke may promote the development of new cell therapy targets and strategies. The spleen will become a potential target of various stem cell therapies for stroke represented by MAPC treatment.

Lymphocyte-to-monocyte ratio on day 7 is associated with outcomes in acute ischemic stroke

The main features of stroke-induced immunosuppression are lymphopenia and deactivation of monocytes in peripheral blood. We hypothesized that lymphocyte-to-monocyte ratio (LMR) in peripheral blood may represent the degree of stroke-induced immunosuppression. To prove this hypothesis, we evaluated whether LMR is associated with risk of post-stroke infection and clinical outcome at 3 months in patients with acute ischemic stroke. We selected patients with stroke in anterior circulation within 24 h from onset. Peripheral blood sampling for differential blood count was performed on days 1 and 7. The LMRs on days 1 and 7 were analyzed to determine associations with excellent outcomes (modified Rankin Scale of score 0-1 at 3 months). One hundred and two patients were included. The initial National Institutes of Health Stroke Scale score (adjusted odd ratio [OR] 0.89; 95% confidence interval [CI], 0.83-0.95; P = 0.001) and LMR on day 7 (adjusted OR 1.49; 95% CI, 1.09-2.02; P = 0.011) were associated with excellent outcomes. LMRs on day 1 were significantly lower in stroke patients with pneumonia (P = 0.007) and pneumonia or urinary tract infection (P = 0.012) than those without infections. LMRs on day 7 were also significantly lower in stroke patients with infection (P = 0.005 in pneumonia, P = 0.003 in urinary tract infection, and P < 0.001 in pneumonia or urinary tract infection) than those without infections. Lower LMRs on day 7 are associated with worse outcomes at 3 months after stroke onset. LMR may be a useful marker for assessing the stroke-induced immunosuppression.

Assessment of immune organ dysfunction in critical illness: utility of innate immune response markers

In critically ill patients, organ dysfunctions are routinely assessed, monitored, and treated. Mounting data show that substantial critical illness-induced changes in the immune system can be observed in most ICU patients and that not only "hyper-inflammation" but also persistence of an anti-inflammatory phenotype (as in sepsis-associated immunosuppression) is associated with increased morbidity and mortality. Despite common perception, changes in functional immunity cannot be adequately assessed by routine inflammatory biomarkers such as C-reactive protein, procalcitonin, or numerical analysis of leukocyte (sub)-counts. Cytokines appear also not suited due to their short half-life and pleiotropy, their unexclusive origin from immune cells, and their potential to undergo antagonization by circulating inactivating molecules. Thus, beyond leukocyte quantification and use of routine biomarkers, direct assessment of immune cell function seems required to characterize the immune systems' status. This may include determination of, e.g., ex vivo cellular cytokine release, phagocytosis activity, and/or antigen-presenting capacity. In this regard, standardized flow-cytometric assessment of the major histocompatibility-II complex human leukocyte antigen (-D related) (HLA-DR) has gained particular interest. Monocytic HLA-DR (mHLA-DR) controls the interplay between innate and adaptive immunity and may serve as a "global" biomarker of injury-associated immunosuppression, and its decreased expression is associated with adverse clinical outcomes (e.g., secondary infection risk, mortality). Importantly, recent data demonstrate that injury-associated immunosuppression can be reversed-opening up new therapeutic avenues in affected patients. Here we discuss the potential scientific and clinical value of assessment of functional immunity with a focus on monocytes/macrophages and review the current state of knowledge and potential perspectives for affected critically ill patients.

The Randomized Controlled STRAWINSKI Trial: Procalcitonin-Guided Antibiotic Therapy after Stroke

Background

Pneumonia is among the most common acute complications after stroke and is associated with poor long-term outcome. Biomarkers may help identifying stroke patients at high risk for developing stroke-associated pneumonia (SAP) and to guide early treatment.

Aims

This trial investigated whether procalcitonin (PCT) ultrasensitive (PCTus)-guided antibiotic treatment of SAP can improve functional outcome after stroke.

Methods

In this international, multicenter, randomized, controlled clinical trial with blinded assessment of outcomes, patients with severe ischemic stroke in the middle cerebral artery territory were randomly assigned within 40 h after symptom onset to PCTus-based antibiotic therapy guidance in addition to stroke unit care or standard stroke unit care alone. The primary endpoint was functional outcome at 3 months, defined according to the modified Rankin Scale (mRS) and dichotomized as acceptable (≤4) or unacceptable (≥5). Secondary endpoints included usage of antibiotics, infection rates, days of fever, and mortality. The trial was registered with http://ClinicalTrials.gov (Identifier NCT01264549).

Results

In the intention-to-treat-analysis based on 227 patients (112 in PCT and 115 in control group), 197 patients completed the 3-month follow-up. Adherence to PCT guidance was 65%. PCT-guided therapy did not improve functional outcome as measured by mRS (odds ratio 0.79; 95% confidence interval 0.45–1.35, p = 0.47). Pneumonia rate and mortality were similar in both groups. Days with fever tended to be lower (p = 0.055), whereas total number of days treated with antibiotics were higher (p = 0.004) in PCT compared to control group. A post hoc analysis including all PCT values in the intention-to-treat population demonstrated a significant increase on the first day of infection in patients with pneumonia and sepsis compared to patients with urinary tract infections or without infections (p < 0.0001).

Conclusion

PCTus-guided antibiotic therapy did not improve functional outcome at 3 months after severe ischemic stroke. PCT is a promising biomarker for early detection of pneumonia and sepsis in acute stroke patients.

The impact of post-stroke complications on in-hospital mortality depends on stroke severity

INTRODUCTION

Controversies remain on whether post-stroke complications represent an independent predictor of poor outcome or just a reflection of stroke severity. We aimed to identify which post-stroke complications have the highest impact on in-hospital mortality by using machine learning techniques. Secondary aim was identification of patient's subgroups in which complications have the highest impact.

PATIENTS AND METHODS

Registro Nacional de Ictus de la Sociedad Española de Neurología is a stroke registry from 42 centers from the Spanish Neurological Society. Data from ischemic stroke patients were used to build a random forest by combining 500 classification and regression trees, to weight up the impact of baseline characteristics and post-stroke complications on in-hospital mortality. With the selected variables, a logistic regression analysis was performed to test for interactions.

RESULTS

12,227 ischemic stroke patients were included. In-hospital mortality was 5.9% and median hospital stay was 7(4-10) days. Stroke severity [National Institutes of Health Stroke Scale > 10, OR = 5.54(4.55-6.99)], brain edema [OR = 18.93(14.65-24.46)], respiratory infections [OR = 3.67(3.02-4.45)] and age [OR = 2.50(2.07-3.03) for >77 years] had the highest impact on in-hospital mortality in random forest, being independently associated with in-hospital mortality. Complications have higher odds ratios in patients with baseline National Institutes of Health Stroke Scale <10.

DISCUSSION

Our study identified brain edema and respiratory infections as independent predictors of in-hospital mortality, rather than just markers of more severe strokes. Moreover, its impact was higher in less severe strokes, despite lower frequency.

CONCLUSION

Brain edema and respiratory infections were the complications with a greater impact on in-hospital mortality, with the highest impact in patients with mild strokes. Further efforts on the prediction of these complications could improve stroke outcome.

Neuroanatomical correlates of stroke-associated infection and stroke-induced immunodepression

BACKGROUND

Infections represent the most frequent medical complications in stroke patients. Their main determinants are dysphagia and a transient state of immunodepression. We analyzed whether distinct anatomical brain regions were associated with the occurrence of stroke-associated infections or immunodepression.

MATERIALS AND METHODS

In 106 patients with acute ischemic stroke, we evaluated the incidence of pneumonia, urinary tract infection, or other infections together with the characterization of biomarkers of immunodepression. Twenty control subjects served to provide reference values. Using voxel-based lesion-symptom mapping, the involvement of gray and white matter structures was correlated with clinical and laboratory findings in crude analyses and in volume adjusted models to rule out associations reflecting differences in the size of the infarction.

RESULTS

Stroke-associated infection occurred in 22 (21%) patients and prevailed in patients with larger infarcts. Volume adjusted voxel-based lesion-symptom mapping revealed the involvement of the superior and middle temporal gyri, the orbitofrontal cortex, the superior longitudinal fasciculus and the inferior fronto-occipital fasciculus amongst infected patients. These associations were similar for pneumonia but not for urinary tract infections. Lymphopenia was associated with lesions of the superior and middle temporal gyri. Laterality did not influence stroke-associated infections or the presence of immunodepressive traits after volume control. The greatest overlap in the neuroanatomical correlates occurred between pneumonia and dysphagia.

CONCLUSION

Infarct volume plays a relevant role in the occurrence of stroke-associated infections, but lesions in specific brain locations such as the superior and lateral temporal lobe and the orbitofrontal cortex are also associated with increased infectious risk, especially pneumonia.

Postischemic Inflammation in Acute Stroke

Cerebral ischemia is caused by arterial occlusion due to a thrombus or an embolus. Such occlusion induces multiple and concomitant pathophysiological processes that involve bioenergetic failure, acidosis, loss of cell homeostasis, excitotoxicity, and disruption of the blood-brain barrier. All of these mechanisms contribute to neuronal death, mainly via apoptosis or necrosis. The immune system is involved in this process in the early phases after brain injury, which contributes to potential enlargement of the infarct size and involves the penumbra area. Whereas inflammation and the immune system both exert deleterious effects, they also contribute to brain protection by stimulating a preconditioning status and to the concomitant repair of the injured parenchyma. This review describes the main phases of the inflammatory process occurring after arterial cerebral occlusion, with an emphasis on the role of single mediators.

Low-Dose Lithium Stabilizes Human Endothelial Barrier by Decreasing MLC Phosphorylation and Universally Augments Cholinergic Vasorelaxation Capacity in a Direct Manner

Lithium at serum concentrations up to 1 mmol/L has been used in patients suffering from bipolar disorder for decades and has recently been shown to reduce the risk for ischemic stroke in these patients. The risk for stroke and thromboembolism depend not only on cerebral but also on general endothelial function and health; the entire endothelium as an organ is therefore pathophysiologically relevant. Regardless, the knowledge about the direct impact of lithium on endothelial function remains poor. We conducted an experimental study using lithium as pharmacologic pretreatment for murine, porcine and human vascular endothelium. We predominantly investigated endothelial vasorelaxation capacities in addition to human basal and dynamic (thrombin-/PAR-1 receptor agonist-impaired) barrier functioning including myosin light chain (MLC) phosphorylation (MLC-P). Low-dose therapeutic lithium concentrations (0.4 mmol/L) significantly augment the cholinergic endothelium-dependent vasorelaxation capacities of cerebral and thoracic arteries, independently of central and autonomic nerve system influences. Similar concentrations of lithium (0.2–0.4 mmol/L) significantly stabilized the dynamic thrombin-induced and PAR-1 receptor agonist-induced permeability of human endothelium, while even the basal permeability appeared to be stabilized. The lithium-attenuated dynamic permeability was mediated by a reduced endothelial MLC-P known to be followed by a lessening of endothelial cell contraction and paracellular gap formation. The well-known lithium-associated inhibition of inositol monophosphatase/glycogen synthase kinase-3-β signaling-pathways involving intracellular calcium concentrations in neurons seems to similarly occur in endothelial cells, too, but with different down-stream effects such as MLC-P reduction. This is the first study discovering low-dose lithium as a drug directly stabilizing human endothelium and ubiquitously augmenting cholinergic endothelium-mediated vasorelaxation. Our findings have translational and potentially clinical impact on cardiovascular and cerebrovascular disease associated with inflammation explaining why lithium can reduce, e.g., the risk for stroke. However, further clinical studies are warranted.

Admission troponin-I predicts subsequent cardiac complications and mortality in acute stroke patients

Purpose

The importance of troponin elevation at stroke presentation remains uncertain. We aimed to assess whether baseline ultrasensitive Troponin I (hs-TnI) predicts cardiac complications and outcome in acute stroke patients.

Method

Stroke patients admitted within 6 h were consecutively enrolled from May 2013 to March 2014. Blood samples were taken at admission to determine hs-TnI by chemiluminescent microparticle immunoassay. hs-TnI > 34.2 pg/ml (male) and >15.6 pg/ml (female) were considered elevated. Complications during in-hospital stay and outcome at 90 days were prospectively recorded. Independent predictors of cardiac complications (heart failure and acute coronary syndrome) and mortality were determined by logistic regression. The additional predictive value of hs-TnI was evaluated by integrated discrimination improvement index. A subanalysis was performed after excluding patients with previous cardiac diseases.

Findings

From 174 patients, 39(22%) had elevated hs-TnI, having these patients higher incidence of cardiac complications (57% versus 19%, p = 0.004). hs-TnI was an independent predictor of cardiac complications (OR = 16.1 (1.7-150.3)) together with diastolic blood pressure (OR = 0.92 (0.86-0.99)). Addition of hs-TnI to clinical variables significantly improved discrimination (IDI = 15.2% (7.8-22.7)). Subanalysis in patients without previous cardiac diseases showed similar results. Elevated hs-TnI was independently associated with 90 days mortality (OR = 3.6 (1.3-9.4)), but addition of hs-TnI to clinical data did not result in an increased discrimination.

Discussion

The present study confers hs-TnI a 2b level of evidence as a diagnostic tool to predict cardiac complications in stroke. Absence of serial hs-TnI measurements and limited sample size are the main weaknesses of the study.

Conclusion

Patients with elevated baseline hs-TnI showed a higher frequency of cardiac complications and a higher mortality. Measurement of hs-TnI in acute stroke might be useful to identify patients at a high risk of cardiac complications and death.

Age and gender leucocytes variances and references values generated using the standardized ONE-Study protocol

Flow cytometry is now accepted as an ideal technology to reveal changes in immune cell composition and function. However, it is also an error-prone and variable technology, which makes it difficult to reproduce findings across laboratories. We have recently developed a strategy to standardize whole blood flow cytometry. The performance of our protocols was challenged here by profiling samples from healthy volunteers to reveal age- and gender-dependent differences and to establish a standardized reference cohort for use in clinical trials. Whole blood samples from two different cohorts were analyzed (first cohort: n = 52, second cohort: n = 46, both 20-84 years with equal gender distribution). The second cohort was run as a validation cohort by a different operator. The "ONE Study" panels were applied to analyze expression of >30 different surface markers to enumerate proportional and absolute numbers of >50 leucocyte subsets. Indeed, analysis of the first cohort revealed significant age-dependent changes in subsets e.g. increased activated and differentiated CD4(+) and CD8(+) T cell subsets, acquisition of a memory phenotype for Tregs as well as decreased MDC2 and Marginal Zone B cells. Males and females showed different dynamics in age-dependent T cell activation and differentiation, indicating faster immunosenescence in males. Importantly, although both cohorts consisted of a small sample size, our standardized approach enabled validation of age-dependent changes with the second cohort. Thus, we have proven the utility of our strategy and generated reproducible reference ranges accounting for age- and gender-dependent differences, which are crucial for a better patient monitoring and individualized therapy. © 2016 International Society for Advancement of Cytometry.

Ischemia, Immunosuppression and Infection--Tackling the Predicaments of Post-Stroke Complications

The incidence of stroke has risen over the past decade and will continue to be one of the leading causes of death and disability worldwide. While a large portion of immediate death following stroke is due to cerebral infarction and neurological complications, the most common medical complication in stroke patients is infection. In fact, infections, such as pneumonia and urinary tract infections, greatly worsen the clinical outcome of stroke patients. Recent evidence suggests that the disrupted interplay between the central nervous system and immune system contributes to the development of infection after stroke. The suppression of systemic immunity by the nervous system is thought to protect the brain from further inflammatory insult, yet this comes at the cost of increased susceptibility to infection after stroke. To improve patient outcome, there have been attempts to lessen the stroke-associated bacterial burden through the prophylactic use of broad-spectrum antibiotics. However, preventative antibiotic treatments have been unsuccessful, and therefore have been discouraged. Additionally, with the ever-rising obstacle of antibiotic-resistance, future therapeutic options to reverse immune impairment after stroke by augmentation of host immunity may be a viable alternative option. However, cautionary steps are required to ensure that collateral ischemic damage caused by cerebral inflammation remains minimal.

Copeptin predicts 10-year all-cause mortality in community patients: a 10-year prospective cohort study

Background:

Copeptin, the C-terminal part of the arginine vasopressin (AVP) precursor peptide, is secreted in response to stress and correlates with adverse clinical outcomes in the acute-care hospital setting. There are no comprehensive data regarding its prognostic value in the community. We evaluated associations of copeptin levels with 10-year mortality in patients visiting their general practitioner (GP) for a respiratory infection included in a previous trial.

Methods:

This is a post hoc analysis including data from 359 patients included in the PARTI trial. Copeptin was measured in batch-analysis on admission and after 7 days. We calculated Cox regression models and area under the receiver operating characteristic curve (AUC) to assess an association of copeptin with mortality and adverse outcome. Follow-up data were collected by GP, patient and relative tracing through phone interviews 10 years after trial inclusion.

Results:

After a median follow-up of 10.0 years, mortality was 9.8%. Median admission copeptin levels (pmol/L) were significantly elevated in non-survivors compared to survivors (13.8, IQR 5.9–27.8; vs. 6.3 IQR 4.1–11.5; p<0.001). Admission copeptin levels were associated with 10-year all-cause mortality [age-adjusted hazard ratio 1.7 (95% CI, 1.2–2.5); p<0.001, AUC 0.68]. Results were similar for discharge copeptin levels. Copeptin also predicted adverse outcomes defined as death, pulmonary embolism and major adverse cardiac and cerebrovascular events.

Conclusions:

In a sample of community-dwelling patients visiting their GP for a respiratory infection, copeptin levels were associated with 10-year all-cause mortality. In conjunction with traditional risk factors, this marker may help to better direct preventive measures in this population.

Neuroinflammatory biomarkers: From stroke diagnosis and prognosis to therapy

Stroke is the third leading cause of death in industrialized countries and one of the largest causes of permanent disability worldwide. Therapeutic options to fight stroke are still limited and the only approved drug is tissue-plasminogen activator (tPA) and/or mechanical thrombectomy. Post-stroke inflammation is well known to contribute to the expansion of the ischemic lesion, whereas its resolution stimulates tissue repair and neuroregeneration processes. As inflammation highly influences susceptibility of stroke patients to overcome the disease, there is an increasing need to develop new diagnostic, prognostic and therapeutic strategies for post-stroke inflammation. This review provides a brief overview of the contribution of the inflammatory mechanisms to the pathophysiology of stroke. It specially focuses on the role of inflammatory biomarkers to help predicting stroke patients' outcome since some of those biomarkers might turn out to be targets to be therapeutically altered overcoming the urgent need for the identification of potent drugs to modulate stroke-associated inflammation. This article is part of a Special Issue entitled: Neuro Inflammation edited by Helga E. de Vries and Markus Schwaninger.

The Effects of Statins on Infections after Stroke or Transient Ischemic Attack: A Meta-Analysis

Background

Previous studies have reported that statins can prevent infections, and these findings were ascribed to the anti-inflammatory and immunomodulatory properties of statins. However, the effects of statins on the risk of infection after stroke or transient ischemic attack (TIA) remain controversial. The aim of this study was to evaluate the relationship between statins and the risk of infection after stroke or TIA by means of a meta-analysis.

Methodology and Findings

Studies were found by searching major electronic databases using key terms and restricting the results to studies published in English language and human studies. Pooled odds ratio (OR) for the association between infection and statins were analyzed using Stata software. A total of five studies that included 8,791 stroke or TIA patients (3,269 patients in the statin use group and 5,522 in the placebo group) were eligible and abstracted. Pooled analysis demonstrated that statins did not significantly affect the incidence of infection after stroke or TIA compared with a placebo (OR 0.819, 95% CI 0.582–1.151, I² = 64.2%, p= 0.025). Sensitivity analyses showed that the removal of any single study did not significantly affect the pooled OR. Cumulative meta-analysis showed that the incidence of infection did not vary by publication year. No statistical evidence of publication bias was found among the studies selected, based on the results of Egger’s (p = 1.000) and Begg’s (p = 0.762) tests.

Conclusions

This meta-analysis does not support the hypothesis that statins reduce the risk of infections in stroke or TIA patients.

Prognostic value of copeptin in patients with acute stroke

CONTEXT

There is a need to improve stroke care through the prompt identification of stroke patients at increased risk of an adverse outcome.

OBJECTIVE

To evaluate the prognostic value of copeptin in patients with stroke.

METHODS

We systematically searched PubMed and Embase for relevant studies. Poor outcome and mortality were analyzed.

RESULTS

Twelve studies, containing 2682 patients, were included. Pooled analysis showed that copeptin is an independent prognostic marker of poor outcome after acute stroke and there is a borderline effect of copeptin in predicting mortality after acute stroke.

CONCLUSIONS

Copeptin is an independent predictor of poor outcome and mortality for patients with acute stroke.

Increased VEGF and decreased SDF-1α in patients with silent brain infarction are associated with better prognosis after first-ever acute lacunar stroke

BACKGROUND

Pre-existing silent brain infarctions (SBIs) have been reported to be associated with better outcomes after first-ever symptomatic ischemic stroke, although the mechanism of this remains unclear. We investigated the association between SBIs, outcomes of acute lacunar infarction, and biomarkers including vascular endothelial growth factor (VEGF), stromal cell-derived factor-1α (SDF-1α), macrophage migration inhibitory factor (MIF), and high-mobility group box-1 (HMGB1).

METHODS

A total of 68 consecutive patients diagnosed with first-ever lacunar infarction (<20 mm) within 24 hours of symptom onset were included in this study. Clinical, laboratory, and imaging data were obtained. Plasma levels of VEGF, SDF-1α, MIF, and HMGB1 were assessed using Enzyme-Linked Immunosorbent Assay kits.

RESULTS

SBIs were noted in 31 of the 68 patients. Although the initial National Institutes of Health Stroke Scale scores were not related with the presence of SBIs (P = .313), patients with SBIs had better outcomes at 3 months (P = .029). Additionally, plasma VEGF levels were higher (P = .035) and SDF-1α levels were lower (P < .001) in patients with SBIs. Logistic regression analysis indicated that VEGF and SDF-1α were independently associated with the presence of SBIs.

CONCLUSIONS

SBIs are associated with favorable outcomes in patients with first-ever acute lacunar infarction and higher levels of VEGF, and lower levels of SDF-1α in these patients may contribute to their more favorable prognosis.

Biomarkers and perfusion--training-induced changes after stroke (BAPTISe): protocol of an observational study accompanying a randomized controlled trial

Background

Physical activity is believed to exert a beneficial effect on functional and cognitive rehabilitation of patients with stroke. Although studies have addressed the impact of physical exercise in cerebrovascular prevention and rehabilitation, the underlying mechanisms leading to improvement are poorly understood. Training-induced increase of cerebral perfusion is a possible mediating mechanism. Our exploratory study aims to investigate training-induced changes in blood biomarker levels and magnetic resonance imaging in patients with subacute ischemic stroke.

Methods/design

This biomarker-driven study uses an observational design to examine a subgroup of patients in the randomized, controlled PHYS-STROKE trial. In PHYS-STROKE, 215 patients with subacute stroke (hemorrhagic and ischemic) receive either 4 weeks of physical training (aerobic training, 5 times a week, for 50 minutes) or 4 weeks of relaxation sessions (5 times a week, for 50 minutes). A convenience sample of 100 of these patients with ischemic stroke will be included in BAPTISe and will receive magnetic resonance imaging (MRI) scans and an additional blood draw before and after the PHYS-STROKE intervention. Imaging scans will address parameters of cerebral perfusion, vessel size imaging, and microvessel density (the Q factor) to estimate the degree of neovascularization in the brain. Blood tests will determine several parameters of immunity, inflammation, endothelial function, and lipometabolism. Primary objective of this study is to evaluate differential changes in MRI and blood-derived biomarkers between groups. Other endpoints are next cerebrovascular events and functional status of the patient after the intervention and after 3 months assessed by functional scores, in particular walking speed and Barthel index (co-primary endpoints of PHYS-STROKE). Additionally, we will assess the association between functional outcomes and biomarkers including imaging results. For all endpoints we will compare changes between patients who received physical fitness training and patients who had relaxation sessions.

Discussion

This exploratory study will be the first to investigate the effects of physical fitness training in patients with ischemic stroke on MRI-based cerebral perfusion, pertinent blood biomarker levels, and functional outcome. The study may have an impact on current patient rehabilitation strategies and reveal important information about the roles of MRI and blood-derived biomarkers in ischemic stroke.

Trial registration

NCT01954797.

Plasma copeptin and long-term outcomes in acute ischemic stroke

OBJECTIVE

The identification of patients at highest risk for adverse outcome who are presenting with acute ischemic stroke to the emergency department remains a challenge. This study firstly investigates the long-term prognostic value of the stress marker copeptin in Chinese patients with acute ischemic stroke.

METHODS

In a prospective study, copeptin levels were measured using a new sandwich immunoassay on admission in plasma of 245 consecutive patients with an acute ischemic stroke. The prognostic value of copeptin to predict the functional outcome and mortality within one year was compared with the National Institutes of Health Stroke Scale score and with other known outcome predictors.

RESULTS

Patients with an unfavorable outcomes and non-survivors had significantly increased copeptin levels on admission (P < 0.0001 and P < 0.0001). Multivariate Cox regression analysis adjusted for common risk factors showed that copeptin was an independent predictor of functional outcome (hazard ratio = 3.88; 95% CI: 1.94-7.77) and non-survivors (hazard ratio = 5.99; 95% CI: 2.55-14.07). The area under the receiver operating characteristic curve of copeptin was 0.75 (95% CI, 0.70-0.82) for functional outcome and 0.867 (95% CI, 0.802-0.933) for mortality.

CONCLUSIONS

Copeptin levels are a novel and complementary biomarker to predict functional outcome and mortality 1 year after acute ischemic stroke.

Is early clinical evidence of autonomic shift predictive of infection after aneurysmal subarachnoid hemorrhage

BACKGROUND

Autonomic shift (AS), characterized by increased sympathetic nervous system activation, has been implicated in neurologically mediated cardiopulmonary dysfunction and immunodepression after stroke. We investigated the prevalence of AS defined by readily available clinical parameters and determined the association of AS with subsequent infection in a cohort of patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

Data were obtained from a single-center cohort study of aSAH patients admitted from January 1, 2007, through April 1, 2012. AS was defined as at least 1 early (<72 hours) routine clinical marker of neurologically mediated cardiopulmonary dysfunction based on electrocardiogram, echocardiogram, cardiac enzymes, or neurogenic pulmonary edema. Multivariable logistic regression models were developed to evaluate the association between AS and subsequent infection after adjusting for other covariates.

RESULTS

A total of 167 patients were included in the analysis (mean age 56, 27% men). AS was seen in 66 of 167 patients (40%; 95% confidence interval [CI], 32%-47%), and infection was seen in 80 of 167 patients (48%; 95% CI, 40%-55%). AS was associated with subsequent infection on unadjusted analysis (odds ratio [OR] 2.11; 95% CI, 1.12-3.97); however, this association was no longer significant when adjusting for other predictors of infection (OR 1.36; 95% CI, .67-2.76). Age, clinical grade, and aneurysm location were all independent predictors of infection after aSAH.

CONCLUSIONS

We identified AS based on readily available clinical markers in 40% of patients with aSAH, though AS defined by these clinical criteria was not an independent predictor of infection. Additional studies may be warranted to determine the optimal definition of AS and the clinical significance of this finding.

Effects of acute exercise and xanthine oxidase inhibition on novel cardiovascular biomarkers

Several sports have been associated with a postexercise increase of cardiac, liver, and skeletal muscle biomarkers of injury. Exhaustive or acute physical exercise causes an increased generation of reactive oxygen species, resulting in cellular injury. Thus, exercise and training may trigger pathophysiological changes in serum concentrations of a variety of biomarkers. In this study, we aimed to evaluate the variation of novel biomarkers of stress and cardiovascular disease such as copeptin, midregional part of proadrenomedullin (MR-proADM), growth differentiation factor 15 (GDF15), soluble vascular endothelial growth factor receptor, and placental growth factor along with uric acid before and after acute high-intensity exercise and allopurinol administration. We also assessed whether allopurinol administration may affect the circulating levels of these biomarkers by inhibition of XO activity. This is a double-blind, placebo-controlled study in which 12 professional football players were divided into 2 experimental groups. An oral dose of 300 mg of allopurinol was administered to one group of six participants 4 hours before a match of the Spanish Football League, whereas the other 6 participants received placebo (cellulose). Venous blood samples were obtained before the match (baseline) and twelve hours afterwards (post-match). Serum MR-proADM levels increased significantly in the placebo group, whereas serum GDF15 levels increased significantly in both the placebo and allopurinol group after the match. No differences in the other parameters tested were found after the match in any experimental group. The trend toward postexercise increase of serum MR-proADM and GDF15 levels shows that the metabolism of these proteins is clearly imbalanced after exercise, which thereby represents a potential source of biological variability in their clinical assessment.

High-density lipoprotein: a novel marker for risk of in-hospital infection in acute ischemic stroke patients?

BACKGROUND

Several studies have shown that high-density lipoprotein (HDL) cholesterol provides protection against bacterial infections. Our aim was to investigate the influence of HDL cholesterol levels on the risk of developing in-hospital infectious complications after an acute ischemic stroke (IS) as well as the possible effect of prestroke statin treatment on this association.

METHODS AND RESULTS

Observational study that included consecutive IS patients during a 5-year period (2006-2010). We analyzed vascular risk factors, prestroke treatments (including statins), laboratory data (including HDL cholesterol levels), stroke severity, and the development of infectious complications (pneumonia, urinary tract infection and sepsis). A multivariate analysis that included HDL cholesterol levels, prior statin treatment and the interaction between both variables was performed to identify those factors associated with the presence of infectious complications. A total of 1,385 patients were included, 130 of whom (9.4%) developed in-hospital infections. The receiver operating characteristic curve showed the predictive value of HDL cholesterol with an area under the curve of 0.597 (95% CI, 0.526-0.668; p = 0.006) and pointed to 38.5 mg/dl of HDL cholesterol (65.5% sensitivity and 53.4% specificity) as the optimal cutoff level for developing infectious complications during hospitalization. An HDL cholesterol level ≥38.5 mg/dl was an independent predictive factor for lower risk of infection (OR 0.308; 95% CI 0.119-0.795), whereas prestroke statin treatment was not associated with the development of infection.

CONCLUSIONS

An HDL cholesterol level ≥38.5 mg/dl was independently associated with lower risk for developing infectious complications in acute IS patients. Statins do not influence this association.

Immunological biomarkers improve the accuracy of clinical risk models of infection in the acute phase of ischemic stroke

Infection is an independent risk factor for adverse outcome in stroke patients. The risk of developing an infection in this setting is partly related to a stroke-induced immunodepression, in which a shift to a predominant Th2 (immunosuppressive) phenotype has been postulated to play a major role. Our aim was to study whether clinical variables or changes in plasma cytokine expression can predict poststroke infections.

PATIENTS AND METHODS

Medical records of 92 stroke patients were reviewed, and the baseline concentration of cytokines from the Th1/Th2 system was determined. Clinical and serological predictors of incident infections and their prognostic significance were sought by means of univariate and multivariate analysis, and two predictive models for developing an infection were constructed by combining independent predictors (strictly clinical in one, and both clinical and serological in the other) for this outcome. The improvement conferred by the addition of immunological markers to the clinical model was assessed by comparing their respective ROC curves and by improvement (Net Reclassification Index and Integrated Discriminator Improvement) analysis.

RESULTS

Nineteen patients (20.7% of the study sample) developed an infection. Ongoing antiplatelet therapy at symptom onset (OR 0.02, 95% CI 0.001-0.23, p = 0.001), diabetes mellitus (OR 9.96, 95% CI 1.32-75.29, p = 0.03), IL-13 level <33 pg/ml (OR 84.16, 95% CI 2.53-2795.18, p = 0.01) and interferon-γ level >8.4 pg/ml (OR 60.17, 95% CI 1.78-2037.23, p = 0.02) were independently associated with the development of infections during hospital admission. The combined regression model predicted infection with an accuracy of 93.4%, an improvement in the predictive capacity of 17% (p < 0.001). Infection was associated with a worse neurological status at hospital discharge (median NIHSS score 11 (6-18) vs. 4 (1-11.5), p = 0.014).

CONCLUSIONS

This study shows that bloodstream biomarkers are useful to improve the accuracy of clinical prognostic models for infection in the acute phase of stroke. The clinical predictors of infection in the acute phase of stroke are relatively well established in the medical literature, but further research to identify the optimal combination of biomarkers (possibly inflammatory and stress markers) to be included in a clinically useful model is needed. Such a model could be subsequently used in clinical trials to assess the effect of prophylactic and/or early antibiotic therapy in this setting, a currently controversial issue in this field.

Post-stroke infections exacerbate ischemic brain injury in middle-aged rats: immunomodulation and neuroprotection by progesterone

We investigated the effect of delayed, prolonged systemic inflammation on stroke outcomes and progesterone (P4) neuroprotection in middle-aged rats. After transient middle cerebral artery occlusion/reperfusion (MCAO) surgery, rats received P4 (8 or 16 mg/kg) or vehicle injections at 2h, 6h and every 24h until day 7 post-occlusion. At 24h post-injury systemic inflammation was induced by giving three doses of lipopolysaccharide (LPS; 50 μg/kg, at 4h intervals) to model post-stroke infections. We measured serum brain-derived neurotrophic factor (BDNF), pro-inflammatory cytokines, and behavioral parameters at multiple times. Serum BDNF levels decreased more in the vehicle+LPS group compared to vehicle-alone at 3 and 7 days post-injury (P<0.05). Vehicle-alone showed a significant increase in interleukin-1β, interleukin-6, and tumor necrosis factor alpha levels at different times following stroke and these levels were further elevated in the vehicle+LPS group. P4 at both doses produced a significant (P<0.05) decline in cytokine levels compared to vehicle and vehicle+LPS. P4 restored BDNF levels at 3 and 7 days post-stroke (P<0.05). Behavioral assessment (rotarod, grip strength, sensory neglect and locomotor activity tests) at 3, 5 and 7 days post-stroke revealed that the vehicle group had significant (P<0.05) deficits in all tests compared to intact controls, and performance was worse in the vehicle+LPS group. P4 at both doses produced significant functional improvement on all tests. Systemic inflammation did not show an additive effect on infarct volume but P4 at both doses showed significant infarct reduction. We suggest that post-stroke infection exacerbates stroke outcomes and P4 exerts neuroprotective/modulatory effects through its systemic anti-inflammatory and BDNF regulatory actions.