Acute ischemic stroke and infections

Research progress of different components of PM2.5 and ischemic stroke

PM2.5 is a nonhomogeneous mixture of complex components produced from multiple sources, and different components of this mixture have different chemical and biological toxicities, which results in the fact that the toxicity and hazards of PM2.5 may vary even for the same mass of PM2.5. Previous studies on PM2.5 and ischemic stroke have reached different or even opposing conclusions, and considering the heterogeneity of PM2.5 has led researchers to focus on the health effects of specific PM2.5 components. However, due to the complexity of PM2.5 constituents, assessing the association between exposure to specific PM2.5 constituents and ischemic stroke presents significant challenges. Therefore, this paper reviews and analyzes studies related to PM2.5 and its different components and ischemic stroke, aiming to understand the composition of PM2.5 and identify its harmful components, elucidate their relationship with ischemic stroke, and thus provide some insights and considerations for studying the biological mechanisms by which they affect ischemic stroke and for the prevention and treatment of ischemic stroke associated with different components of PM2.5.

NLR family pyrin domain containing 3 (NLRP3) inflammasomes and peripheral neuropathic pain - Emphasis on microRNAs (miRNAs) as important regulators

Neuropathic pain is caused by the lesion or disease of the somatosensory system and can be initiated and/or maintained by both central and peripheral mechanisms. Nerve injury leads to neuronal damage and apoptosis associated with the release of an array of pathogen- or damage-associated molecular patterns to activate inflammasomes. The activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome contributes to neuropathic pain and may represent a novel target for pain therapeutic development. In the current review, we provide an up-to-date summary of the recent findings on the involvement of NLRP3 inflammasome in modulating neuropathic pain development and maintenance, focusing on peripheral neuropathic conditions. Here we provide a detailed review of the mechanisms whereby NLRP3 inflammasomes contribute to neuropathic pain via (1) neuroinflammation, (2) apoptosis, (3) pyroptosis, (4) proinflammatory cytokine release, (5) mitochondrial dysfunction, and (6) oxidative stress. We then present the current research literature reporting on the antinociceptive effects of several natural products and pharmacological interventions that target activation, expression, and/or regulation of NLRP3 inflammasome. Furthermore, we emphasize the effects of microRNAs as another regulator of NLRP3 inflammasome. In conclusion, we summarize the possible caveats and future perspectives that might provide successful therapeutic approaches against NLRP3 inflammasome for treating or preventing neuropathic pain conditions.

The clinical value of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and D-dimer-to-fibrinogen ratio for predicting pneumonia and poor outcomes in patients with acute intracerebral hemorrhage

Background

This study aimed to investigate the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and D-dimer-to-fibrinogen ratio (DFR) as predictors of pneumonia and poor outcomes in patients with acute intracerebral hemorrhage (ICH).

Methods

We retrospectively examined patients with acute ICH treated in our institution from May 2018 to July 2020. Patient characteristics, laboratory testing data, radiologic imaging data, and 90-day outcomes were recorded and analyzed.

Results

Among the 329 patients included for analysis, 183 (55.6%) developed pneumonia. Systolic blood pressure, initial hematoma volume, D-dimer concentration, NLR, PLR, DFR, and white blood cell, platelet, neutrophil, and lymphocyte counts at admission were significantly higher in patients who developed pneumonia than in those who did not; however, the Glasgow coma scale (GCS) score at admission was significantly lower in pneumonia patients compared with non-pneumonia patients (all P <0.05). Multivariate logistic regression showed that the NLR and PLR were independent predictors of pneumonia, and the NLR and DFR were independent predictors of poor 90-day outcomes (modified Rankin scale score 4–6).

Conclusion

The NLR and PLR were independent predictors of pneumonia and the NLR and DFR were independent predictors of poor 90-day outcomes. The NLR, PLR, and DFR can provide prognostic information about acute ICH patients.

Al-buhadiliy A, De Waard M, Sabatier JM, Khan Khalil AA, Saad HM, Batiha GES. Role of Neuropilin 1 in COVID-19 Patients with Acute Ischemic Stroke

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection can trigger the adaptive and innate immune responses, leading to uncontrolled inflammatory reactions and associated local and systematic tissue damage, along with thromboembolic disorders that may increase the risk of acute ischemic stroke (AIS) in COVID-19 patients. The neuropilin (NRP-1) which is a co-receptor for the vascular endothelial growth factor (VEGF), integrins, and plexins, is involved in the pathogenesis of AIS. NRP-1 is also regarded as a co-receptor for the entry of SARS-CoV-2 and facilitates its entry into the brain through the olfactory epithelium. NRP-1 is regarded as a cofactor for binding of SARS-CoV-2 with angiotensin-converting enzyme 2 (ACE2), since the absence of ACE2 reduces SARS-CoV-2 infectivity even in presence of NRP-1. Therefore, the aim of the present study was to clarify the potential role of NRP-1 in COVID-19 patients with AIS. SARS-CoV-2 may transmit to the brain through NRP-1 in the olfactory epithelium of the nasal cavity, leading to different neurological disorders, and therefore about 45% of COVID-19 patients had neurological manifestations. NRP-1 has the potential capability to attenuate neuroinflammation, blood-brain barrier (BBB) permeability, cerebral endothelial dysfunction (ED), and neuronal dysfunction that are uncommon in COVID-19 with neurological involvement, including AIS. Similarly, high NRP-1 serum level is linked with ED, oxidative stress, and the risk of pulmonary thrombosis in patients with severe COVID-19, suggesting a compensatory mechanism to overcome immuno-inflammatory disorders. In conclusion, NRP-1 has an important role in the pathogenesis of COVID-19 and AIS, and could be the potential biomarker linking the development of AIS in COVID-19. The present findings cannot provide a final conclusion, and thus in silico, experimental, in vitro, in vivo, preclinical, and clinical studies are recommended to confirm the potential role of NRP-1 in COVID-19, and to elucidate the pharmacological role of NRP-1 receptor agonists and antagonists in COVID-19.

Potential association between bacterial infections and ischemic stroke based on fifty case-control studies: A systematic review and meta-analysis

Background

Stroke is considered as one of the most important concerns in health care centers around the world. By definition there are two types of stroke including ischemic stroke and hemorrhagic stroke. Approximately three-quarters of stroke cases are ischemic strokes, which occur due to several risk factors such as hypertension, obesity, atherosclerosis, diabetes mellitus, osteoarthritis, and inflammatory responses. In recent years, infectious diseases have noticed as a new risk factor for ischemic stroke. Given the importance of the issue, some bacteria that cause chronic infections, especially Chlamydia pneumonia, Helicobacter pylori, Mycoplasma pneumonia, Mycobacterium tuberculosis, and Coxiella burnetii have been considered.

Methods

In the present meta-analysis, we reviewed 50 case-control studies and assessed the possible association of bacterial infections with the occurrence of ischemic stroke.

Results

We analyzed the information of 33,978 participants in several nested case-control studies, and ultimately showed that bacterial infections could increase the risk of ischemic stroke. Our results suggest that bacterial infections significantly increase in the risk of ischemic stroke (OR: 1.704; 1.57-1.84 with 95% CIs; p value = 0.01).

Conclusions

In this meta-analysis, a significant relationship was observed between infection by three bacteria such as C. pneumoniae, H. pylori, and M. tuberculosis with the occurrence of ischemic stroke. Furthermore, due to the similarity between TLRVYK domain in β2-glycoprotein-I and TLRVYK peptide in various of microorganisms, produced antibodies against pathogens interact with β2-glycoprotein-I, hence the cross-reaction phenomenon increases the positive relationship between infectious diseases and ischemic stroke.

Dynamic Process of Secondary Pulmonary Infection in Mice With Intracerebral Hemorrhage

Stroke is a common central nervous system disease in clinical practice. Stroke patients often have infectious complications, such as pneumonia and infections of the urinary tract and gastrointestinal tract. Although it has been shown that translocation of the host gut microbiota to the lungs and immune dysfunction plays a vital role in the development of infection after ischemic stroke, the occurrence and mechanism of pulmonary infection at different time points after hemorrhagic cerebral remain unclear. In this study, the changes in the immune system and intestinal barrier function in mice during disease development were investigated at 1 day (M 1 d), 3 days (M 3 d) and 7 days (M 7 d) following hemorrhagic stroke to clarify the mechanism of secondary pulmonary infection. The experimental results revealed that after hemorrhagic stroke, model mice showed increased brain damage from day 1 to 3, followed by a trend of brain recovery from day 3 to 7 . After hemorrhagic stroke, the immune system was disturbed in model mice. Significant immunosuppression of the peripheral immune system was observed in the M 3 d group but improved in the M 7 d group. Staining of lung tissues with hematoxylin and eosin (H&E) and for inflammatory factors revealed considerable disease and immune disorders in the M 7 d group. Stroke seriously impaired intestinal barrier function in mice and significantly changed the small intestine structure. From 1 to 7 d after stroke, intestinal permeability was increased, whereas the levels of markers for intestinal tight junctions, mucus and immunoglobulin A were decreased. Analysis based on 16S rRNA suggested that the microflora in the lung and ileum was significantly altered after stroke. The composition of microflora in lung and ileum tissue was similar in the M 7d group, suggesting that intestinal bacteria had migrated to lung tissue and caused lung infection at this time point after hemorrhagic stroke. In stroke mice, the aggravation of intestinal barrier dysfunction and immune disorders after intracerebral hemorrhage, promoted the migration of enteric bacteria, and increased the risk of pneumonia poststroke. Our findings reveal the dynamic process of infection after hemorrhagic stroke and provide clues for the optimal timing of intervention for secondary pulmonary infection in stroke patients.

Validation of the Predisposition Infection Response Organ (PIRO) dysfunction score for the prognostic stratification of patients with sepsis in the Emergency Department

OBJECTIVE

There are many different methods for computing the Predisposition Infection Response Organ (PIRO) dysfunction score. We compared three PIRO methods (PIRO1 (Howell), PIRO2 (Rubulotta) and PIRO3 (Rathour)) for the stratification of mortality and high level of care admission in septic patients arriving at the Emergency Department (ED) of an Italian Hospital.

DESIGN, SETTING AND PARTICIPANTS

We prospectively collected clinical data of 470 patients admitted due to infection in the ED to compute PIRO according to three different methods. We tested PIRO variables for the prediction of mortality in the univariate analysis. Calculation and comparison were made of the area under the receiver operating curve (AUC) for the three PIRO methods, SOFA and qSOFA.

RESULTS

Most of the variables included in PIRO were related to mortality in the univariate analysis. Increased PIRO scores were related to higher mortality. In relation to mortality, PIRO 1 performed better than PIRO2 at 30 d ((AUC 0.77 (0.716-0.824) vs. AUC 0.699 (0.64-0.758) (p=0.03) and similarly at 60 d (AUC 0.767 (0.715-0.819) vs AUC 0.709 (0.656-0.763)(p=0.55)); PIRO1 performed similarly to PIRO3 (AUC 0.765 (0.71-0.82) at 30 d, AUC 0.754 (0.701-0.806) at 60 d, p=ns). Both PIRO1 and PIRO3 were as good as SOFA referred to mortality (AUC 0.758 (0.699, 0.816) at 30 d vs. AUC 0.738 (0.681, 0.795) at 60 d; p=ns). For high level of care admission, PIRO proved inferior to SOFA.

CONCLUSIONS

We support the use of PIRO1, which combines ease of use and the best performance referred to mortality over the short term. PIRO2 proved to be less accurate and more complex to use, suffering from missing microbiological data in the ED setting.

Factors associated with early improvement after intravenous thrombolytic treatment in acute ischemic stroke

OBJECTIVE

: The aim of this study was to determine the factors associated with early neurological improvement (ENI) in patients who experienced acute ischemic stroke and were treated with intravenous recombinant tissue plasminogen activator (IV rt-PA), and determine the relationship with the outcome at the first control.

METHOD

: This study included 377 patients who were treated with IV rt-PA in Izmir Dokuz Eylül University Hospital between January 2010 and October 2018. ENI was defined as a 4 or more improvement in the National Institutes of Health Stroke Scale (NIHSS) score in the first hour, the twenty-fourth hour and the seventh day when compared to the pretreatment phase. The modified Rankin Scale (mRS) 0-1 score was defined as 'very good outcome'.

RESULTS

: The basal NIHSS (p=0.003, p=0.003, p=0.022) was high in the first hour, twenty-fourth hour, and seventh day ENI groups. Blood urea nitrogen (BUN) level was low in the first- and twenty-fourth-hour ENI groups (p=0.007, p=0.020). Furthermore, admission glucose was low at the twenty-fourth hour and on the seventh day ENI groups (p=0.005, p=0.048). A high infarct volume was observed on magnetic resonance imaging (MRI) at the twenty-fourth hour and on the seventh day non-ENI groups (p= <0.001, p= <0.001).

CONCLUSION

: Management of factors associated with ENI and determination of treatment strategies accordingly are important for obtaining a better clinical outcome. It can help quickly select patients, who, even though they will not respond to rt-PA, may be appropriate candidates for bridging therapy.

Stroke associated with Mycoplasma hominis infection: a case report

BACKGROUND

Mycoplasmas are the smallest prokaryotic microorganisms in nature. Many cases of stroke post-Mycoplasma pneumoniae infection have been reported, particularly in the pediatric population. However, Mycoplasma hominis infection has not previously been associated with stroke.

CASE PRESENTATION

We report the case of a 36-year-old Greek woman who presented with an extensive stroke with an unspecified cause. She had a concurrent genital infection with Mycoplasma hominis for an unknown duration.

CONCLUSION

An association may exist between stroke and the immune response to Mycoplasma hominis infection.

Post-stroke infection in acute ischemic stroke patients treated with mechanical thrombectomy does not affect long-term outcome

Introduction

The impact of an infection that requires antibiotic treatment (IRAT) after an acute ischemic stroke (AIS) treated with mechanical thrombectomy (MT) remains unclear.

Aim

Here, we studied the prevalence and the profile of IRAT in patients with AIS treated with MT, aiming to identify predictive factors and prognostic implications at 90 days after stroke.

Material and methods

We analyzed parameters available within 24 h after AIS including demographics, risk factors, National Institutes of Health Stroke Scale (NIHSS) upon admission and 24 h later, hemorrhagic transformation (HT) on computed tomography, and several clinical and biochemical markers. The outcome measures were the modified Rankin Scale (mRS) 0-2 and 90 days post-stroke mortality.

Results

We included 291 patients; in 184 (63.2%) patients MT was preceded by intravenous thrombolysis (IVT), and 83 (28.5%) patients developed IRAT. Multivariate analysis showed that male sex and hemorrhagic transformation on CT taken 24 h after stroke increased the risk of IRAT. We found that younger age, male sex, lower delta NIHSS, shorter time from stroke onset to groin puncture, better recanalization and a lack of hemorrhagic transformation on CT taken 24 h after stroke favorably affected outcome at day 90. Multivariate analysis showed that older age, higher delta NIHSS, unknown stroke etiology and lack of treatment with IVT were independent predictors of death up to day 90. Infection that required antibiotic treatment did not enter in the models for the studied outcome measures.

Conclusions

In AIS patients treated with MT, IRAT is not an independent factor that affects favorable outcome or mortality 90 days after stroke.

Assessment, typo error on Author's response of Post Ischemic Stroke Infections

Background

Infection is a common complication in acute phase after stroke, and even in specialized stroke units, it remains one of the major complications. The relationship between infections and acute ischemic stroke is complex and bidirectional. Infections can result in ischemic stroke, and the rate of infection is increased after ischemic stroke.

Aim of work

The aim of this study is to estimate the incidence of post-stroke infections in the Egyptian patients, with determination of the most common infections, possible risk factors, and their clinical implications.

Methods

The study was conducted on one hundred adult patients with acute ischemic stroke, full medical history, thorough clinical examination, routine laboratory investigations, estimation of erythrocyte sedimentation rate and C-reactive protein, abdominal ultrasound, plain X-ray of the chest, culture and sensitivity, non-contrast computed tomography, magnetic resonance imaging for patients with normal CT studies of the brain, duplex study of both carotids and vertebral, ECG, and echocardiography, any further investigations needed and lastly collected data statistically analyzed.

Results

The results of our study showed that 32 patients (32%) developed post-stroke infection. Post-stroke infections increased with higher age and female gender. Post-stroke infections were strongly correlated to the presence of atrial fibrillation, previous stroke, or transient ischemic attacks. The occurrence of post-stroke infection was significantly correlated to stroke severity, size of infarction, and carotid stenosis. Post-stroke infection was also correlated with the occurrence of multiple post-stroke neurological complications. Infections that occurred post-stroke were pneumonia (21%) and urinary tract infection (15%), blood (5%), and subcutaneous infection (3%).

Conclusion

Stroke is a major health problem, and infection is one of the commonest post-stroke complications. Post-stroke infection significantly affects clinical outcome and being strongly associated with occurrence of neurological complications.

Abstract: study was conducted on one hundred adult patients with acute ischemic stroke, full medical history, thorough clinical examination, routine laboratory investigations, estimation of erythrocyte sedimentation rate and C-reactive protein, abdominal ultrasound, plain X-ray of the chest, culture and sensitivity, non-contrast computed tomography (CT), magnetic resonance imaging (MRI) for patients with normal CT studies of the brain, duplex study of both carotids and vertebral, electrocardiography (ECG), and echocardiography, any further investigations needed and lastly collected data statistically analyzed.

Increased neutrophil-to-lymphocyte ratio predicts the development of post-stroke infections in patients with acute ischemic stroke

Background

Infections could increase the risk of poor outcome in patients with acute ischemic stroke (AIS). The peripheral neutrophil-to-lymphocyte ratio (NLR) is an important indicator of inflammation. The purpose of our study was to investigate the association increased NLR with post stroke infections (PSI) in AIS.

Methods

In this study, we included 606 consecutive patients with AIS within 24 h. The NLR was calculated by dividing absolute neutrophil counts by absolute lymphocyte counts. Receiver operating characteristic (ROC) curve was performed to identify the optimal cut point of NLR for PSI. The relationship between NLR and PSI was analyzed by multivariable analysis.

Results

We assessed 606 consecutive patients with AIS. ROC curve analysis showed that the optimal cut point of NLR for PSI was NLR ≥ 5.79. Compared with no PSI, patients with PSI have higher NLR, older age, higher NIHSS, higher PCT, higher percentage of nasogastric tube feeding and indwelling urinary catheter (P < 0.05). Multivariable analysis showed that NLR ≥ 5.79 [adjusted odds ratio (aOR),4.52; 95% confidence interval (CI),3.02–6.76; P < 0.001], older age (aOR,1.03; 95% CI, 1.00–1.05; P = 0.009), higher admission NIHSS (aOR,1.13; 95%CI, 1.07–1.18; P < 0.001), indwelling urinary catheter (aOR1.83; 95%CI, 1.08–3.10; P = 0.026], and nasogastric tube feeding (aOR2.52; 95%CI, 1.38–4.59; P = 0.003) were associated with increased risk of PSI.

Conclusions

Higher NLR can predict PSI in AIS patients. The NLR may help to select high-risk patients to start intervention in time.

Predictive value of the sequential organ failure assessment (SOFA) score for prognosis in patients with severe acute ischemic stroke: a retrospective study

OBJECTIVE

To identify the risk factors for early death and determine the predictive value of the sequential organ failure assessment (SOFA) score for prognosis of severe acute ischemic stroke (AIS).

METHODS

A total of 110 patients with severe AIS were enrolled and divided into the non-survivor (n = 34) and survivor groups (n = 76). Logistic regression analysis was conducted to identify risk factors for early death, while the receiver operator characteristic (ROC) curve was used to determine the predictive effect of the SOFA score on prognosis.

RESULTS

Logistic regression analysis showed that urinary tract infection (odds ratio [OR] = 17.364, 95% confidence interval [CI]: 1.903-158.427), mechanical ventilation (OR = 1.754, 95% CI: 1.648-2.219), and osmotic therapy (OR = 2.835, 95% CI: 1.871-5.102) were significantly correlated with early death of severe AIS. ROC curve analysis of the area under the curve after hospitalization showed that the maximum SOFA and ΔSOFA scores exceeded 0.7.

CONCLUSION

Our study shows that urinary tract infection, mechanical ventilation, and osmotic therapy are risk factors for early death of severe AIS. The SOFA score has good predictive value for prognosis of severe AIS. These findings may provide a guideline for improving clinical outcome.

Validation of the Predisposition Infection Response Organ (PIRO) dysfunction score for the prognostic stratification of patients with sepsis in the Emergency Department

OBJECTIVE

There are many different methods for computing the Predisposition Infection Response Organ (PIRO) dysfunction score. We compared three PIRO methods (PIRO1 (Howell), PIRO2 (Rubulotta) and PIRO3 (Rathour)) for the stratification of mortality and high level of care admission in septic patients arriving at the Emergency Department (ED) of an Italian Hospital.

DESIGN, SETTING AND PARTICIPANTS

We prospectively collected clinical data of 470 patients admitted due to infection in the ED to compute PIRO according to three different methods. We tested PIRO variables for the prediction of mortality in the univariate analysis. Calculation and comparison were made of the area under the receiver operating curve (AUC) for the three PIRO methods, SOFA and qSOFA.

RESULTS

Most of the variables included in PIRO were related to mortality in the univariate analysis. Increased PIRO scores were related to higher mortality. In relation to mortality, PIRO 1 performed better than PIRO2 at 30 d ((AUC 0.77 (0.716-0.824) vs. AUC 0.699 (0.64-0.758) (p=0.03) and similarly at 60 d (AUC 0.767 (0.715-0.819) vs AUC 0.709 (0.656-0.763)(p=0.55)); PIRO1 performed similarly to PIRO3 (AUC 0.765 (0.71-0.82) at 30 d, AUC 0.754 (0.701-0.806) at 60 d, p=ns). Both PIRO1 and PIRO3 were as good as SOFA referred to mortality (AUC 0.758 (0.699, 0.816) at 30 d vs. AUC 0.738 (0.681, 0.795) at 60 d; p=ns). For high level of care admission, PIRO proved inferior to SOFA.

CONCLUSIONS

We support the use of PIRO1, which combines ease of use and the best performance referred to mortality over the short term. PIRO2 proved to be less accurate and more complex to use, suffering from missing microbiological data in the ED setting.

Lyme Neuroborreliosis: Clinical Outcomes, Controversy, Pathogenesis, and Polymicrobial Infections

Lyme borreliosis is the object of numerous misconceptions. In this review, we revisit the fundamental manifestations of neuroborreliosis (meningitis, cranial neuritis, and radiculoneuritis), as these have withstood the test of time. We also discuss other manifestations that are less frequent. Stroke, as a manifestation of Lyme neuroborreliosis, is considered in the context of other infections. The summary of the literature regarding clinical outcomes of neuroborreliosis leads to its controversies. We also include new information on pathogenesis and on the polymicrobial nature of tick-borne diseases. In this way, we update the review that we wrote in this journal in 1995. ANN NEUROL 2019;85:21-31.

Baroreflex sensitivity is associated with post-stroke infections. An open, prospective study

BACKGROUND AND PURPOSE

Autonomic nervous system (ANS) seems to play an important role in the post-stroke immunosuppression syndrome with increased susceptibility to infections. The aim of this study was to investigate if ANS activity measured at admission is associated with post-stroke infections.

METHODS

We prospectively analyzed patients with acute ischemic stroke. ANS was measured using the cross-correlational baroreflex sensitivity (BRS) at admission. The occurrence and cause of in-hospital infections was assessed based on the clinical and laboratory examination. Demographic and clinical variables including initial stroke severity, dysphagia, procedures as nasogastric tubes, central venous and urinary catheters and mechanical ventilation were included in the analysis.

RESULTS

We included 161 patients with ischemic stroke, of those 49 (30.4%) developed a nosocomial infection during the first 7 days of hospital stay. Patients with infections had significantly lower BRS (median 3 vs 5 ms/mmHg, p < .001) higher initial NIHSS (median 15 vs 5, p < .001), had more often non-lacunar etiology and underwent more invasive procedures. In the multivariable regression model decreased BRS (adjusted OR 1.21, 95% CI 1.03-1.41, p = .02), admission NIHSS (adjusted OR 1.10, 95% CI 1.02-1.19, p = .02) and invasive procedures (adjusted OR 1.46, 95% CI 1.03-2.06, p = .03) were independently associated with infection after ischemic stroke.

CONCLUSIONS

Decreased BRS was independently associated with infections after ischemic stroke. Autonomic shift may play an important role in increased susceptibility to infections after stroke. The possible diagnostic and therapeutic relevance of this finding deserves further research.

Infections Increase the Risk of 30-Day Readmissions Among Stroke Survivors

Background and Purpose- Hospitals are increasingly using 30-day readmission (30dRA) to define the quality of care and reimbursement. We hypothesized that common infections occurring during the stroke stay are associated with 30dRA. Methods- We conducted a weighted analysis of the federally managed 2013 National Readmission Database to assess the relationship between infection during a stroke hospitalization and 30dRA among ischemic stroke survivors. Ischemic stroke, common infections (defined as sepsis, pneumonia, and urinary tract infection), and comorbidities were identified using International Classification of Diseases Ninth Revision ( ICD-9) diagnosis codes, and intravenous tPA (tissue-type plasminogen activator) or intra-arterial therapy was identified using ICD-9 procedure codes. Survey design logistic regression models were fit to estimate crude and adjusted odds ratios and 95% CI for the association between infections and 30dRA. Results- Among 319 317 ischemic stroke patients, 12.1% were readmitted within 30 days, and 29% had an infection during their index hospitalization. Patients with infection during their stroke admission had a 21% higher odds of being readmitted than patients without any type of infection (adjusted odds ratio, 1.21; 95% CI, 1.16-1.26). The association between infection and unplanned readmission was similar with an increased odds of unplanned readmission (adjusted odds ratio, 1.23; 95% CI, 1.18-1.29). When assessing specific types of infections, only urinary tract infections were associated with 30dRA in adjusted models (odds ratio, 1.10; 95% CI, 1.04-1.16). Conclusions- In a nationally representative cohort, patients who had a common infection during their stroke hospitalization were at increased odds of being readmitted. Patients with infection may benefit from earlier poststroke follow-up or closer monitoring.

Clinical study of chlamydia pneumoniae infection in patients with coronary heart disease

Background

This study aims to investigate the chlamydia pneumoniae infection (PC) in patients with coronary heart disease.

Methods

A total of 92 patients with coronary heart disease, who were treated with percutaneous coronary intervention (PCI), were selected as the case group. In addition, 50 healthy people were enrolled as the control group. The incidences of CP infection and serum Chlamydia pneumoniae IgA antibody (CP-IgA), high sensitive C-reactive protein (hs-CRP), and interleukin-6 (IL-6) were compared in these two groups. The classification of coronary artery lesion, the incidence of perioperative cardiovascular events, and adverse prognosis events within six months after procedure were compared.

Results

The incidence of CP infection in the case group was higher (42.4% vs. 0%, P < 0.05). Furthermore, 17 patients were at grade I, 39 patients were at grade II, and 36 patients were at grade III. The incidences for these three kinds of patients were 17.6, 30.8, and 66.7%. The incidence of CP infection at grade III was higher than that of grade I or II (P < 0.05). Serum CP-IgA, hs-CRP and IL-6 levels increased with the severity of the coronary artery disease (P < 0.05), and the serum hs-CRP and IL-6 levels of patients with perioperative cardiovascular events were higher (P < 0.05). Moreover, the serum CP-IgA levels of the patients with adverse prognosis events were also higher (P < 0.05).

Conclusions

Patients with coronary heart disease have a high CP infection rate. The degree of infection is relevant to the severity of the coronary artery lesions and postoperative prognosis of patients, suggesting that CP infection may be an important factor affecting the incidence and prognosis of coronary heart disease.

Protective activities of polysaccharides from Cipangopaludina chinensis against high-fat-diet-induced atherosclerosis via regulating gut microbiota in ApoE-deficient mice

The supplementation of sulfated polysaccharides extracted from C. chinensis slows down the development of atherosclerosis caused by high-fat-diet-induced AS via regulating gut microbiota.

Post-stroke infections and preventive antibiotics in stroke: Update of clinical evidence

This review provides an update of evidence on post-stroke infections and the use of preventive antibiotics in stroke. Infection is a common complication after stroke, affecting between 15% and 30% of the patients. The predictors for post-stroke infection can be divided into three categories: clinical factors, anatomical (stroke related) factors and immunological factors. The relation between the occurrence of a post-stroke infection and functional outcome remained subject of debate, but it seems likely that the occurrence of these infections has a causal relation with poor functional outcome and mortality. In the first meta-analysis on preventive antibiotic therapy, almost a decade ago, its beneficial effect on post-stroke infection rate was clear; however, the effect on functional outcome remained uncertain because included studies were small and heterogeneous. Afterwards, three large phase-3 RCTs were published and a Cochrane meta-analysis was performed. It has now become clear that, despite the finding that overall infections are reduced, preventive antibiotic therapy in the acute phase of stroke does neither improve functional outcome, nor decrease mortality rates. This does not yet mean that further research on preventive antibiotics in stroke is useless: the pathophysiology and etiology of post-stroke infections are unclear and the use of preventive antibiotics in specific subgroups of stroke patients could still be very effective. This is currently being studied. Besides, preventive antibiotic therapy might be cost-effective by increasing quality-adjusted life years. Thirdly, research for the upcoming years might put more emphasis on the effect of stroke on immunological alterations.

The role of NLRP3 inflammasome in stroke and central poststroke pain

BACKGROUND

NLRP3 inflammasome plays a prominent role in the pathogenesis and progression of many diseases, such as type 2 diabetes mellitus, obesity, atherosclerosis, and Alzheimer's disease. However, little knowledge is known about the role of NLRP3 inflammasome in central post-stroke pain (CPSP).

METHODS

We selected relevant studies by searching PubMed, Embase, and Medline from inception through February, 2018. We systematically reviewed available publications according to the terms "NLRP3 inflammasome" and "stroke" or "central post-stroke pain" in the title/abstract field.

RESULTS

We reviewed the articles and put forward two possible ways for NLRP3 inflammasome in CPSP. One way is that NLRP3 activation causes cerebral cortex injure, decreasing descending projection fiber to thalamus. Such condition may let GABAergic releases reduce, making the ventral basal (VB) neurons excitability increased. Finally, CPSP occur. Another way is that NLRP3 inflammasome leads to thalamic lesion and strengthens inflammatory response of microglia at the same time. Persistent inflammation causes GABAergic alteration in thalamus reticular neurons (TRN) to restrain VB interneurons functions, contributing to CPSP.

CONCLUSIONS

These possible mechanisms will help become knowledgeable about the occurrence CPSP and provide potential therapy for CPSP.

Ischemic stroke induces gut permeability and enhances bacterial translocation leading to sepsis in aged mice

Aging is an important risk factor for post-stroke infection, which accounts for a large proportion of stroke-associated mortality. Despite this, studies evaluating post-stroke infection rates in aged animal models are limited. In addition, few studies have assessed gut microbes as a potential source of infection following stroke. Therefore we investigated the effects of age and the role of bacterial translocation from the gut in post-stroke infection in young (8-12 weeks) and aged (18-20 months) C57Bl/6 male mice following transient middle cerebral artery occlusion (MCAO) or sham surgery. Gut permeability was examined and peripheral organs were assessed for the presence of gut-derived bacteria following stroke. Furthermore, sickness parameters and components of innate and adaptive immunity were examined. We found that while stroke induced gut permeability and bacterial translocation in both young and aged mice, only young mice were able to resolve infection. Bacterial species seeding peripheral organs also differed between young (Escherichia) and aged (Enterobacter) mice. Consequently, aged mice developed a septic response marked by persistent and exacerbated hypothermia, weight loss, and immune dysfunction compared to young mice following stroke.

Should preventive antibiotics be used in patients with acute stroke? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Infection is a common complication in acute stroke. Whether or not preventive antibiotics reduce the risk of infection or even lead to a favorable outcome and reduction of mortality after a stroke still remains equivocal. This review was performed to update the current knowledge on the effect and possible benefits of prophylactic antibiotic therapy in patients with stroke.

METHODS

A systematic review and meta-analysis of preventive antibiotics`effect on the incidence of infection, favorable outcome (mRS≤2) and mortality in patients with acute stroke is performed with relevant randomized controlled trials.

RESULTS

Six studies were identified, involving 4125 participants. Compared with the control group, the treated groups were significantly less prone to suffer from early overall infections [RR = 0.52, 95%CI (0.39, 0.70), p<0.0001], early pneumonia [RR = 0.64, 95%CI (0.42, 0.96), p = 0.03] and early urinary tract infections [RR = 0.35, 95%CI (0.25, 0.48), p<0.00001]. However, there was no significant difference in overall mortality [RR = 1.07, 95%CI (0.90, 1.27), p = 0.44], early mortality [RR = 0.99, 95%CI (0.78, 1.26), p = 0.92], late mortality [RR = 1.12, 95%CI (0.94, 1.35), p = 0.21] or favorable outcome [RR = 1.00, 95%CI (0.92, 1.08), p = 0.98].

CONCLUSION

Although preventive antibiotic treatment did reduce the occurrence of early overall infections, early pneumonia and early urinary tract infection in patients with acute stroke, this advantage was not eventually translated to a favorable outcome and reduction in mortality. Future studies are warranted to identify any subgroup of stroke patients who might benefit from preventive antibiotic treatment.

Clinacanthus nutans Mitigates Neuronal Apoptosis and Ischemic Brain Damage Through Augmenting the C/EBPβ-Driven PPAR-γ Transcription

Clinacanthus nutans Lindau (C. nutans) is a traditional herbal medicine widely used in Asian countries for treating a number of remedies including snake and insect bites, skin rashes, viral infections, and cancer. However, the underlying molecular mechanisms for its action and whether C. nutans can offer protection on stroke damage in brain remain largely unknown. In the present study, we demonstrated protective effects of C. nutans extract to ameliorate neuronal apoptotic death in the oxygen-glucose deprivation model and to reduce infarction and mitigate functional deficits in the middle cerebral artery occlusion model, either administered before or after hypoxic/ischemic insult. Using pharmacological antagonist and siRNA knockdown approaches, we demonstrated ability for C. nutans extract to protect neurons and ameliorate ischemic injury through promoting the anti-apoptotic activity of peroxisome proliferator-activated receptor-gamma (PPAR-γ), a stress-induced transcription factor. Reporter and chromatin immunoprecipitation promoter analysis further revealed C. nutans extract to selectively increase CCAAT/enhancer binding protein (C/EBP)β binding to specific C/EBP binding site (-332~-325) on the PPAR-γ promoter to augment its transcription. In summary, we report a novel transcriptional activation involving C/EBPβ upregulation of PPAR-γ expression to suppress ischemic neuronal apoptosis and brain infarct. Recognition of C. nutans to enhance the C/EBPβ → PPAR-γ neuroprotective signaling pathway paves a new way for future drug development for prevention and treatment of ischemic stroke and other neurodegenerative diseases.

The Efficacy of Prophylactic Antibiotics on Post-Stroke Infections: An Updated Systematic Review and Meta-Analysis

Post-stroke infections are common complications in acute stroke patients and are associated with an unfavorable functional outcome. However, reports on the effects of prophylactic antibiotics treatment on post-stroke infections are conflicting, especially those on post-stroke pneumonia and outcomes. We searched the PubMed, Embase, and Web of Knowledge databases up through March 11^th, 2016. Seven randomized controlled trials including 4261 patients were analyzed among this systematic review and meta-analysis. We found preventive antibiotics treatment at the time of stroke onset did reduce the incidence of infections in adults with acute stroke (OR = 0.57, 95% CI: 0.38–0.85, P = 0.005), including reducing the number of urinary tract infections (OR = 0.34, 95% CI: 0.26–0.46, P < 0.001), but did not significantly decrease the rate of post-stroke pneumonia (OR = 0.91, 95% CI: 0.73–1.13, P = 0.385). Importantly, antibiotics treatment also showed no significant effect on the number of fatalities among stroke patients (OR = 1.07, 95% CI: 0.90–1.26, P = 0.743) and functional outcome scores on the modified Rankin Scale (OR = 1.76, 95% CI: 0.86–3.63, p = 0.124). Our study indicated that preventive antibiotics treatment not reduced the rate of post-stroke pneumonia or mortality, even though decreased the risk of infections, especially urinary tract infections. Thus, preventive antibiotics treatment may not be recommended for acute stroke patients.

Prophylactic Antibiotic Therapy for Preventing Poststroke Infection

Infections, in particular pneumonia, are common complications in patients with acute stroke and are associated with a less favorable neurologic and functional outcome. Patients with severe stroke and dysphagia are at highest risk of infection. Experimental and clinical data suggest stroke-induced immunodeficiency as a major factor contributing to the high incidence of infection after stroke. Preclinical studies support the potential benefit of preventive antibiotic therapy in acute stroke for lowering the incidence of infection and improving clinical outcome. Several smaller clinical trials on preventive antibiotic therapy in patients with stroke conducted during the last 10 years yielded inconclusive results. Recently, 2 large, open-label, controlled trials failed to demonstrate an improved clinical outcome after preventive antibiotic therapy in patients with acute stroke treated in specialized stroke units. In the "Preventive Antibiotics in Stroke Study", antibiotic therapy lowered the rate of infection but did not influence outcome. In the STROKE-INF study, performed in patients with dysphagia after stroke, antibiotic therapy did not lower the incidence of pneumonia and had no prognostic significance. At present, preventive antibiotic therapy cannot be recommended as a therapeutic option for acute stroke.

Prophylactic antibiotic treatment in severe acute ischemic stroke: the Antimicrobial chemopRrophylaxis for Ischemic STrokE In MaceDonIa-Thrace Study (ARISTEIDIS)

Infections represent a leading cause of mortality in patients with acute ischemic stroke, but it is unclear whether prophylactic antibiotic treatment improves the outcome. We aimed to evaluate the effects of this treatment on infection incidence and short-term mortality. This was a pragmatic, prospective multicenter real-world analysis of previously independent consecutive patients with acute ischemic stroke who were >18 years, and who had at admission National Institutes of Health Stroke Scale (NIHSS) >11. Patients with infection at admission or during the preceding month, with axillary temperature at admission >37 °C, with chronic inflammatory diseases or under treatment with corticosteroids were excluded from the study. Among 110 patients (44.5 % males, 80.2 ± 6.8 years), 31 (28.2 %) received prophylactic antibiotic treatment, mostly cefuroxime (n = 21). Prophylactic antibiotic treatment was administered to 51.4 % of patients who developed infection, and to 16.4 % of patients who did not (p < 0.001). Independent predictors of infection were NIHSS at admission [relative risk (RR) 1.16, 95 % confidence interval (CI) 1.08-1.26, p < 0.001] and prophylactic antibiotic treatment (RR 5.84, 95 % CI 2.03-16.79, p < 0.001). The proportion of patients who received prophylactic antibiotic treatment did not differ between patients who died during hospitalization and those discharged, or between patients who died during hospitalization or during follow-up and those who were alive 3 months after discharge. Prophylactic administration of antibiotics in patients with severe acute ischemic stroke is associated with an increased risk of infection during hospitalization, and does not affect short-term mortality risk.

Diffusion-weighted MRI abnormalities in an outbreak of Streptococcus agalactiae Serotype III, multilocus sequence type 283 meningitis

PURPOSE

In 2015, an outbreak of group B streptococcal (GBS) infection caused by Streptococcus agalactiae Serotype III, multilocus sequence type 283, related to consuming infected raw freshwater fish, affected more than 200 patients in Singapore. We describe the clinical, laboratory, and neuroimaging features of a subgroup of adults with central nervous system (CNS) infections caused by GBS.

MATERIALS AND METHODS

The database of the Singapore Neurologic Infections Program (SNIP), a national multicenter study for surveillance of infectious neurologic disease, was reviewed to select patients with GBS CNS infection during the outbreak. Cases were diagnosed on the basis of clinical features, cerebrospinal fluid (CSF) findings and identification or isolation of Streptococcus agalactiae in the blood or CSF. Demographic, clinical and neuroradiological information was obtained prospectively and retrospectively abstracted.

RESULTS

Fourteen patients (6 male, 8 female; median age, 58 years) presented with fever, meningism, headache, encephalopathy, focal neurological deficits, and/or seizures. All except two were previously healthy. Diffusion-weighted imaging (DWI) on admission was abnormal in 13 patients, showing tiny hyperintensities in the subarachnoid space (7 patients), ventricles (6 patients) and brain parenchyma (8 patients); 5 patients had cerebellar abnormalities.

CONCLUSION

Among healthy non-pregnant adults infected with Serotype III, multilocus sequence type 283 GBS meningitis linked to eating infected raw freshwater fish, DWI detected small pus collections and unusual cerebellar involvement. A collaborative national surveillance system that includes MRI can be helpful during unusual food-borne zoonotic infectious disease outbreaks.

LEVEL OF EVIDENCE

4 J. Magn. Reson. Imaging 2017;45:507-514.

Innate Immunity and Inflammation Post-Stroke: An α7-Nicotinic Agonist Perspective

Stroke is one of the leading causes of death and long-term disability, with limited treatment options available. Inflammation contributes to damage tissue in the central nervous system across a broad range of neuropathologies, including Alzheimer's disease, pain, Schizophrenia, and stroke. While the immune system plays an important role in contributing to brain damage produced by ischemia, the damaged brain, in turn, can exert a powerful immune-suppressive effect that promotes infections and threatens the survival of stroke patients. Recently the cholinergic anti-inflammatory pathway, in particular its modulation using α7-nicotinic acetylcholine receptor (α7-nAChR) ligands, has shown potential as a strategy to dampen the inflammatory response and facilitate functional recovery in stroke patients. Here we discuss the current literature on stroke-induced inflammation and the effects of α7-nAChR modulators on innate immune cells.

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.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Gastrointestinal complications after ischemic stroke

Ischemic stroke is an important cause of morbidity and mortality, and currently the leading cause of adult disability in developed countries. Stroke is associated with various non-neurological medical complications, including infections and thrombosis. Gastrointestinal complications after stroke are also common, with over half of all stroke patients presenting with dysphagia, constipation, fecal incontinence or gastrointestinal bleeding. These complications are associated with increased hospital length of stay, the development of further complications and even increased mortality. In this article we review the epidemiology, pathophysiology, diagnosis, management and prevention of the most common gastrointestinal complications associated with ischemic stroke.

Comparison of mobile apps for the leading causes of death among different income zones: a review of the literature and app stores

Background

The advances achieved in technology, medicine, and communications in the past decades have created an excellent scenario for the improvement and expansion of eHeath and mHealth in particular. Mobile phones, smartphones, and tablets are exceptional means for the application of mobile health, especially for those diseases and health conditions that are the deadliest worldwide.

Objective

The main aim of this paper was to compare the amount of research and the number of mobile apps dedicated to the diseases and conditions that are the leading causes of death according to the World Health Organization grouped by different income regions. These diseases and conditions were ischemic heart disease; stroke and other cerebrovascular diseases; lower respiratory infections; chronic obstructive pulmonary disease; diarrheal diseases; HIV/AIDS; trachea, bronchus, and lung cancers; malaria; and Alzheimer disease and other dementias.

Methods

Two reviews were conducted. In the first, the systems IEEE Xplore, Scopus, Web of Knowledge, and PubMed were used to perform a literature review of applications related to the mentioned diseases. The second was developed in the currently most important mobile phone apps stores: Google play, iTunes, BlackBerry World, and Windows Phone Apps+Games.

Results

Search queries up to June 2013 located 371 papers and 557 apps related to the leading causes of death, and the following findings were obtained. Alzheimer disease and other dementias are included in the diseases with more apps, although it is not among the top 10 causes of death worldwide, whereas lower respiratory infections, the third leading cause of death, is one of the less researched and with fewer apps. Two diseases that are the first and second of low-income countries (lower respiratory infections and diarrheal diseases) have very little research and few commercial applications. HIV/AIDS, in the top 6 of low-income and middle-income zones, is one of the diseases with more research and applications, although it is not in the top 10 in high-income countries. Trachea, bronchus, and lung cancers are the third cause of death in high-income countries but are one of the least researched diseases with regard to apps.

Conclusions

Concerning mobile apps, there is more work done in the commercial field than in the research field, although the distribution among the diseases is similar in both fields. In general, apps for common diseases of low- and middle-income countries are not as abundant as those for typical diseases of developed countries. Nevertheless, there are some exceptions such as HIV/AIDS, due to its important social conscience; and trachea, bronchus and lung cancers, which was totally unexpected.

Immunological consequences of ischemic stroke

The treatment of ischemic stroke is one of the great challenges in modern neurology. The localization and the size of the infarct determine the long-term disability of stroke survivors. Recent observations have revealed that stroke also alters the function of the immune system and vice versa: At the site of the infarct, a local inflammatory response develops that enhances brain lesion development. In experimental stroke, proof-of-concept studies confirm that inhibition of this immune response reduces lesion volume and improves outcome. In the peripheral blood of stroke patients, though, lymphocytopenia and monocyte dysfunction develop. These changes reflect a clinically relevant impairment of bacterial defense mechanisms because they are associated with an enhanced risk to acquire post-stroke infections. Stress hormones have been identified as important mediators of stroke-induced immune suppression. The pharmacological inhibition of beta adrenergic receptors, but not the inhibition of steroids, is effective in reducing infection and improving clinical outcome in experimental stroke; catecholamine release therefore appears causally related to stroke-induced immune suppression. Strong evidence supports the hypothesis that these immune alterations impact the clinical course of stroke patients. Thus, the development of new therapeutic strategies targeted to alter the immunological consequences of stroke appears promising. However, to date, the beneficial effects seen in experimental stroke have not been successfully translated into a clinical trial. This brief review summarizes the current understanding of the immunological consequences of ischemic stroke. Finally, we propose a concept that links the peripheral immune suppression with the development of local inflammation.

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.

Superiority of preventive antibiotic treatment compared with standard treatment of poststroke pneumonia in experimental stroke: a bed to bench approach

Stroke patients are prone to life-threatening bacterial pneumonia. Previous experimental stroke studies have demonstrated that preventive antibiotic treatment (PAT) improves outcome compared with placebo treatment, which however does not model the clinical setting properly. Here we investigate whether PAT is superior to the current clinical 'gold standard' for treating poststroke infections. Therefore, we modeled stroke care according to the current stroke guidelines recommending early antibiotic treatment after diagnosing infections. To reliably diagnose pneumonia in living mice, we established a general health score and a magnetic resonance imaging protocol for radiologic confirmation. Compared with standard treatment after diagnosis by these methods, PAT not only abolished pneumonia successfully but also improved general medical outcome. Both, preventive and standard antibiotic treatment using enrofloxacin improved survival in a similar way compared with placebo treatment. However, in contrast to standard treatment, only PAT improved functional outcome assessed by gait analysis. In conclusion, standard and preventive treatment approach reduced poststroke mortality, however at the cost of a worse neurologic outcome compared with preventive approach. These data support the concept of PAT for treating patients at risk for poststroke infections and warrant phase III trials to prove this concept in clinical setting.

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.

Stroke in Renaissance time: the case of Francesco I de' Medici

Francesco I de' Medici (1541-1587), the second Grand Duke of Tuscany, was one of the members of the Medici family who ruled Florence during the centuries of the Renaissance. When, in 1857, all members of the Medici family were exhumed and definitively buried in the place where they still lie buried today, a painter, Giuseppe Moricci (Florence 1806-1879), who attended the ceremony, depicted the corpse of Francesco I in a perfect state of preservation. The painting shows a right spastic hemiparesis with a facial droop, a claw-hand appearance, the right shoulder internally rotated, the calf muscle wasted and the clubfoot confirmed by an orthopedic footwear in the coffin. The hemiparesis and consequent disability were likely concealed when Francesco I was alive, since in official portraits the Grand Duke appeared in perfect physical condition. However, chronicles reported that he had suffered from malaria and syphilis. Later in his life, temper and behavioral changes as well as emotional instability were documented, together with handwriting deterioration and seizures. We postulate that Francesco I had suffered from a stroke consequent to syphilis, a new aggressive and rapidly spreading infectious disease at that time in Italy. Francesco's governmental skills were presumably altered due to these diseases. Disability consequent to stroke was likely concealed by official portrayers and biographers of Francesco I during his life, consistent with the King's two bodies theory common since the Middle Ages: while the King's physical body is destined to die, the political one is everlasting. Infectious diseases have remained a leading cause of stroke in underdeveloped countries until recently, but noncommunicable causes are now prevailing worldwide.

Stroke and the immune system: from pathophysiology to new therapeutic strategies

Stroke is the second most common cause of death worldwide and a major cause of acquired disability in adults. Despite tremendous progress in understanding the pathophysiology of stroke, translation of this knowledge into effective therapies has largely failed, with the exception of thrombolysis, which only benefits a small proportion of patients. Systemic and local immune responses have important roles in causing stroke and are implicated in the primary and secondary progression of ischaemic lesions, as well as in repair, recovery, and overall outcome after a stroke. However, potential therapeutic targets in the immune system and inflammatory responses have not been well characterised. Development of novel and effective therapeutic strategies for stroke will require further investigation of these pathways in terms of their temporal profile (before, during, and after stroke) and risk-to-benefit therapeutic ratio of modulating them.

Autonomic Shift and Increased Susceptibility to Infections After Acute Intracerebral Hemorrhage

Background and Purpose—

High infection rate after severe stroke may partly relate to brain-induced immunodepression syndrome. However, the underlying pathophysiology remains unclear. The aim of the current study was to investigate the role of autonomic shift in increased susceptibility to infection after acute intracerebral hemorrhage (ICH).

Methods—

We retrospectively analyzed 62 selected patients with acute ICH from our prospective database. Autonomic shift was assessed using the cross-correlational baroreflex sensitivity (BRS). The occurrence and cause of in-hospital infections were assessed based on the clinical and laboratory courses. Demographic and clinical data including initial stroke severity, hemorrhage volume, intraventricular blood extension, history of aspiration, and invasive procedures such as mechanical ventilation, surgical hematoma evacuation, external ventricular drainage, central venous and urinary catheters, and nasogastric feeding were recorded and included in the analysis.

Results—

We identified 36 (58%) patients with infection during the first 5 days of hospital stay. Patients with infections had significantly lower BRS, higher initial NIHSS scores, larger hemorrhages, and more frequently had intraventricular blood extension and underwent invasive procedures. In the multivariate regression model, decreased BRS (OR, 0.54; 95% CI, 0.32–0.91; P =0.02) and invasive procedures (OR, 2.32; 95% CI, 1.5–3.6; P <0.001) remained independent predictors for an infection after ICH.

Conclusions—

Decreased BRS was independently associated with infections after ICH. Autonomic shift may play an important role in increased susceptibility to infections after acute brain injury including ICH. The possible therapeutic relevance of autonomic modulation warrants further studies.

Immunological consequences of ischemic stroke: immunosuppression and autoimmunity

Stroke may be accompanied by immunological consequences including local autoimmunity and peripheral immune suppression. Since the blood brain barrier is disturbed cells of the immune system gain direct access to the brain parenchyma. Here local autoimmunity contributes to lesion formation and, in experimental stroke, inhibition of this immune response has been shown to be beneficial. More recently, however, stroke has been shown to also induce severe peripheral immune suppression which predisposes for subsequent bacterial infections that impair the clinical outcome. Here we summarize current knowledge on the immunological consequences of ischemic stroke and will discuss implications of these findings for our understanding of the immunopathogenesis of Multiple Sclerosis.