Relationships of Hematocrit With Chronic Covert and Acute Symptomatic Lacunar Ischemic Lesions

BACKGROUND AND OBJECTIVES

Red blood cell (RBC) concentrations are known to associate with ischemic stroke. It is unclear whether RBC concentrations associate specifically with small vessel disease lacunar infarcts. We investigated the hypothesis that RBC concentrations associate with both chronic covert and acute symptomatic brain MRI lacunar infarcts.

METHODS

A cross-sectional observational analysis was performed across 2 cohorts with available hematocrit (as the assessment of RBC concentration exposure) and MRI outcome data. The primary setting was a population-based cohort of stroke-free, older adult (>50 years) participants from the Northern Manhattan Study (NOMAS) enrolled between 2003 and 2009. A second replication sample consisted of patients admitted with acute stroke and enrolled into the Columbia Stroke Registry (CSR) between 2005 and 2020. Associations of hematocrit with (1) chronic, covert lacunar infarcts and (2) symptomatic (i.e., acute) lacunar strokes were separately assessed from the NOMAS and CSR cohorts, respectively, using general additive models after adjusting for relevant covariates.

RESULTS

Of 1,218 NOMAS participants analyzed, 6% had chronic, covert lacunar infarcts. The association between hematocrit and these covert lacunar infarcts was U-shaped (χ2 = 9.21 for nonlinear associations; p = 0.03), with people with hematocrit extremes being more likely to have covert lacunar infarcts. Of the 1,489 CSR patients analyzed, 23% had acute lacunar strokes. In this sample, only the relationships of increased hematocrit concentrations and lacunar strokes were replicated (adjusted coefficient β = 0.020; SE = 0.009; p = 0.03).

DISCUSSION

We identified relationships of hematocrit with MRI lacunar infarcts in both stroke-free and ischemic stroke cohorts, respectively. The relationship between increased hematocrit concentrations with lacunar infarcts was replicated in both cohorts. Further studies are required to clarify the mechanisms behind the relationships of hematocrit with ischemic cerebral small vessel disease.

Rab7a activation promotes degradation of select tight junction proteins at the blood-brain barrier after ischemic stroke

The stability of tight junctions (TJs) between endothelial cells (ECs) is essential to maintain blood-brain barrier (BBB) function in the healthy brain. Following ischemic stroke, TJ strand dismantlement due to protein degradation leads to BBB dysfunction, yet the mechanisms driving this process are poorly understood. Here, we show that endothelial-specific ablation of Rab7a, a small GTPase that regulates endolysosomal protein degradation, reduces stroke-induced TJ strand disassembly resulting in decreased paracellular BBB permeability and improved neuronal outcomes. Two pro-inflammatory cytokines, TNFα and IL1β, but not glucose and oxygen deprivation, induce Rab7a activation via Ccz1 in brain ECs in vitro, leading to increased TJ protein degradation and impaired paracellular barrier function. Silencing Rab7a in brain ECs in vitro reduces cytokine-driven endothelial barrier dysfunction by suppressing degradation of a key BBB TJ protein, Claudin-5. Thus, Rab7a activation by inflammatory cytokines promotes degradation of select TJ proteins leading to BBB dysfunction after ischemic stroke.

Red Blood Cell Transfusions Are Not Associated With Incident Complications or Poor Outcomes in Patients With Intracerebral Hemorrhage

Background Anemia is associated with poor intracerebral hemorrhage (ICH) outcomes, yet the relationship of red blood cell (RBC) transfusions to ICH complications and functional outcomes remains unclear. We investigated the impact of RBC transfusion on hospital thromboembolic and infectious complications and outcomes in patients with ICH. Methods and Results Consecutive patients with spontaneous ICH enrolled in a single-center, prospective cohort study from 2009 to 2018 were assessed. Primary analyses assessed relationships of RBC transfusions on incident thromboembolic and infectious complications occurring after the transfusion. Secondary analyses assessed relationships of RBC transfusions with mortality and poor discharge modified Rankin Scale score 4 to 6. Multivariable logistic regression models adjusted for baseline demographics and medical disease severity (Acute Physiology and Chronic Health Evaluation II), and ICH severity (ICH score).Of 587 patients with ICH analyzed, 88 (15%) received at least one RBC transfusion. Patients receiving RBC transfusions had worse medical and ICH severity. Though patients receiving RBC transfusions had more complications at any point during the hospitalization (64.8% versus 35.9%), we found no association between RBC transfusion and incident complications in our regression models (adjusted odds ratio [aOR], 0.71 [95% CI, 0.42-1.20]). After adjusting for disease severity and other relevant covariates, we found no significant association between RBC transfusion and mortality (aOR, 0.87 [95% CI, 0.45-1.66]) or poor discharge modified Rankin Scale score (aOR, 2.45 [95% CI, 0.80-7.61]). Conclusions In our cohort with ICH, RBC transfusions were expectedly given to patients with higher medical and ICH severity. Taking disease severity and timing of transfusions into account, RBC transfusion was not associated with incident hospital complications or poor clinical ICH outcomes.

Relationships of Hemoglobin Concentration, Ischemic Lesions, and Clinical Outcomes in Patients With Intracerebral Hemorrhage

BACKGROUND

Hemoglobin concentration and diffusion-weighted imaging (DWI) ischemic lesions are separately known to be associated with poor intracerebral hemorrhage (ICH) outcomes. While hemoglobin concentrations have known relationships with ischemic stroke, it is unclear whether hemoglobin concentration is associated with DWI ischemic lesions after ICH. We sought to investigate the hypothesis that hemoglobin concentrations would associate with DWI lesions after ICH and further investigated their relationships with clinical outcomes.

METHODS

Supratentorial ICH patients enrolled between 2010 and 2016 to a prospective, multicenter, observational cohort study (ERICH study [Ethnic/Racial Variations of Intracerebral Hemorrhage]) were assessed. Patients from this study with baseline, admission hemoglobin, and hospitalization magnetic resonance imaging were analyzed. Hemoglobin was examined as the primary exposure variable defined as a continuous variable (g/dL). Magnetic resonance imaging DWI ischemic lesion presence was assessed as the primary radiographic outcome. Primary analyses assessed relationships of hemoglobin with DWI lesions. Secondary analyses assessed relationships of DWI lesions with poor 3-month outcomes (modified Rankin Scale score, 4-6). These analyses were performed using separate multivariable logistic regression models adjusting for relevant covariates.

RESULTS

Of 917 patients with ICH analyzed, mean baseline hemoglobin was 13.8 g/dL (±1.9), 60% were deep ICH, and DWI lesions were identified in 27% of the cohort. In our primary analyses, increased hemoglobin, defined as a continuous variable, was associated with DWI lesions (adjusted odds ratio, 1.21 per 1 g/dL change in hemoglobin [95% CI, 1.07-1.37]) after adjusting for sex, race, ICH severity, time to magnetic resonance imaging, and acute blood pressure change. In secondary analyses, DWI lesions were associated with poor 3-month outcomes (adjusted odds ratio, 1.83 [95% CI, 1.24-2.69]) after adjusting for similar covariates.

CONCLUSIONS

We identified novel relationships between higher baseline hemoglobin concentrations and DWI ischemic lesions in patients with ICH. Further studies are required to clarify the role of hemoglobin concentration on both cerebral small vessel disease pathophysiology and ICH outcomes.

Hemoglobin Concentration Impacts Viscoelastic Hemostatic Assays in ICU Admitted Patients

OBJECTIVES

Low hemoglobin concentration impairs clinical hemostasis across several diseases. It is unclear whether hemoglobin impacts laboratory functional coagulation assessments. We evaluated the relationship of hemoglobin concentration on viscoelastic hemostatic assays in intracerebral hemorrhage (ICH) and perioperative patients admitted to an ICU.

DESIGN

Observational cohort study and separate in vitro laboratory study.

SETTING

Multicenter tertiary referral ICUs.

PATIENTS

Two acute ICH cohorts receiving distinct testing modalities: rotational thromboelastometry (ROTEM) and thromboelastography (TEG), and a third surgical ICU cohort receiving ROTEM were evaluated to assess the generalizability of findings across disease processes and testing platforms. A separate in vitro ROTEM laboratory study was performed utilizing ICH patient blood samples.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Relationships between baseline hemoglobin and ROTEM/TEG results were separately assessed across patient cohorts using Spearman correlations and linear regression models. A separate in vitro study assessed ROTEM tracing changes after serial hemoglobin modifications from ICH patient blood samples. In both our ROTEM (n = 34) and TEG (n = 239) ICH cohorts, hemoglobin concentrations directly correlated with coagulation kinetics (ROTEM r: 0.46; p = 0.01; TEG r: 0.49; p < 0.0001) and inversely correlated with clot strength (ROTEM r: -0.52, p = 0.002; TEG r: -0.40, p < 0.0001). Similar relationships were identified in perioperative ICU admitted patients (n = 121). We continued to identify these relationships in linear regression models. When manipulating ICH patient blood samples to achieve lower hemoglobin concentrations in vitro, we similarly identified that lower hemoglobin concentrations resulted in progressively faster coagulation kinetics and greater clot strength on ROTEM tracings.

CONCLUSIONS

Lower hemoglobin concentrations have a consistent, measurable impact on ROTEM/TEG testing in ICU admitted patients, which appear to be artifactual. It is possible that patients with low hemoglobin may appear to have normal viscoelastic parameters when, in fact, they have a mild hypocoagulable state. Further work is required to determine if these tests should be corrected for a patient's hemoglobin concentration.

Abstract TP231: Low Hemoglobin Causes Cerebral Hypoxia Resulting In Changes In Blood-brain Barrier Function In Mice

Introduction: Low hemoglobin is associated with stroke and poor cerebrovascular outcomes. It is unclear whether hemoglobin concentrations directly impact cerebrovascular health. Thus, we sought to investigate the role of hemoglobin concentration on cerebral hypoxia and blood brain barrier (BBB) function in murine models of anemia.

Hypothesis: Low hemoglobin will cause relevant cerebral hypoxic changes and impair BBB function.

Methods: Two different models of anemia and their respective controls were generated from 30 8-week-old, female C57/BL6 mice. The separate cohorts generated included: 1) an acute anemia model cohort via anti-TER119 injection (red blood cell hemolysis) compared to IgG control injected mice; 2) chronic anemia model cohort via iron-deficient chow compared to iron replete diet control. Hemoglobin concentrations were assessed using modified Drabkin assays. Mice were euthanized by intracardiac perfusion with saline and fixative and the brain was dissected and processed for histological analysis of vascular permeability (IgG), microglia number and activation (Iba1 and CD68), response to hypoxia (HIF1α) and endothelial markers of BBB function (GLUT1). Statistical analyses were performed using two-tailed Student's t-tests.

Results: Hemoglobin concentrations were lower in our separate anemia model mice compared to their respective controls (acute anemia: 5.5 ± 4.02 vs 13.1 ± 1.69, p=0.007; chronic anemia: 7.9 ± 1.05 vs 11.9 ± 2.31, p=0.0006). Postmortem histological analyses revealed stronger microglial activation (p<0.005) and higher microglial expression of hypoxia-response protein HIF1α (p<0.05) in both acute and chronic anemia models compared to their respective controls. Additionally, anemic mice had increased vascular permeability to serum IgG and decreased expression of the endothelial-specific glucose transporter GLUT1 (p<0.05).

Conclusions: Anemic mice appear to display stronger microglial activation, greater HIF1α expression, and BBB dysfunction compared to non-anemic mice. Future studies will be needed to further clarify cellular and molecular mechanisms driving relationships between anemia, hypoxia, BBB dysfunction and clinical outcomes in cerebrovascular disease.

Abstract TP117: Temporal Serum Iron And Hemoglobin Changes In Patients From The High Dose Deferoxamine In Intracerebral Hemorrhage Trial

Introduction: Following intracerebral hemorrhage (ICH), elevated cerebral tissue iron concentrations are seen. It is unclear how peripheral serum iron concentrations change over time and how they relate to anemia after ICH. Given the known impacts of iron concentrations and anemia on clinical outcomes, we explored serum iron biomarker and hemoglobin concentration changes after acute ICH.

Methods: A post hoc analysis of patients with available serial (baseline and 5 day) serum biomarker data from the multicenter, High Dose Deferoxamine in Intracerebral Hemorrhage (HI-DEF) trial was performed. Changes of serum hemoglobin, iron, transferrin, and ferritin were assessed using repeated measure ANOVA analyses. Deferoxamine treatment and poor 90 day modified Rankin Scale 4-6 were separately assessed as between subject factors for these laboratory changes.

Results: Of 42 ICH patients analyzed, the mean age was 64, 62% were male, median ICH volume was 15.7mL (IQR 5.7-37.5), and baseline anemia was seen in 19%. We identified significant decrements of hemoglobin (mean difference -1.4 g/dL; 95%CI: -1.9 to -0.9; p<0.0001), iron (mean difference -16.9 ug/dL; 95%CI: -29.7 to -4.1; p=0.01), transferrin (mean difference -43.9 ng/mL; 95%CI: -56.6 to -31.3; p<0.0001), and conversely, significant ferritin elevations (mean difference 104.5 ug/L; 95%CI: 52.5-156.6; p<0.0001) at 5 days. Anemia was identified in 43% of patients at 5 days. Deferoxamine did not have a significant impact on these repeated measures. Patients with poor long-term outcomes had greater decrements in hemoglobin compared to those with good outcomes (mean difference: -1.5 g/dL; 95%CI: -2.6 to -0.3; p=0.01).

Conclusions: Serum iron and hemoglobin concentrations decrease significantly over time following ICH. Patients with worse long term ICH outcomes had greater hemoglobin decrements during their hospitalization. The aggregate iron biomarker and hemoglobin concentration changes suggest anemia development may be due to anemia of inflammation. Further work is required to address the pathophysiologic difference between systemic and central iron homeostasis mechanisms following ICH and the impacts that ICH has on inflammation, systemic iron homeostasis, anemia, and clinical outcomes.

Abstract WP125: Relationships Of Hemoglobin With Ischemic Lesions After Intracerebral Hemorrhage

Introduction: Hemoglobin concentrations and diffusion weighted imaging (DWI) lesions are separately known to be associated with poor intracerebral hemorrhage (ICH) outcomes. Though hemoglobin concentrations are related to both hypoxia and thrombosis at their extremes, it is unknown whether hemoglobin concentrations relate to DWI lesions after ICH.

Methods: Spontaneous, supratentorial ICH patients with available baseline hemoglobin and hospitalized MRI data enrolled into a multicenter cohort study between 2010-2016 were analyzed. Baseline hemoglobin was assessed as both a continuous variable (g/dL) and categorical variable (<11, 11 to <13, 13 to <15, >/=15 g/dL). Primary analyses assessed relationships of baseline hemoglobin with MRI DWI lesions. Secondary analyses assessed independent relationships of hemoglobin and DWI lesions with poor 3-month outcomes (modified Rankin Scale [mRS] 4-6). Separate multivariable regression models assessed these relationships after adjusting for relevant covariates.

Results: Of 917 ICH patients analyzed, the mean baseline hemoglobin was 13.8 g/dL (+/-1.9), 60% were deep ICH, and DWI lesions were identified in 27% of the cohort. In our primary analyses, increased hemoglobin, defined as a continuous variable, was associated with DWI lesions (adjusted OR 1.21, 95% CI: 1.07-1.37) after adjusting for sex, race, ICH severity, time to MRI, and blood pressure treatment change. In secondary analyses, DWI lesions were associated with poor 3-month outcomes (adjusted OR 1.83, 95% CI: 1.24-2.69) adjusting for similar covariates. We identified associations of low hemoglobin categories, when referenced to hemoglobin 13 to <15 g/dL, with poor outcomes (<11 g/dL: adjusted OR 1.99, 95% CI: 1.05-3.79; 11 to <13 g/dL: adjusted OR 1.62, 95% CI: 1.04-2.52). Effect estimates of high hemoglobin (>/=15 g/dL) with poor outcomes were smaller and imprecise (adjusted OR 1.39, 95% CI: 0.89-2.17).

Conclusions: We identified novel relationships between higher baseline hemoglobin concentrations and DWI lesions in ICH patients. Further studies are required to clarify the role of hemoglobin concentrations on both cerebral small vessel disease pathophysiology and ICH outcomes.

Abstract TP119: Relationships Of Female Sex With Intracerebral Hemorrhage Characteristics And Outcomes

Introduction: Biological sex is known to impact cerebrovascular disease characteristics and clinical outcomes. While in intracerebral hemorrhage (ICH) it is known that biological sex impacts ICH incidence, it is less clear whether biological sex impacts ICH outcomes.

Hypothesis: Female sex will be associated with ICH characteristics and clinical outcomes.

Methods: Spontaneous ICH patients enrolled into a prospective observational ICH cohort study between 2009-2020 were assessed. Patients with prior anticoagulant use and secondary etiologies of ICH were excluded from the analysis. Female sex was assessed as the primary exposure variable. Primary analyses assessed relationships of female sex with radiographic outcomes: ICH location, ICH volume, hematoma expansion (>33% and/or >6mL). Secondary analyses assessed relationships of female sex with clinical outcomes: poor discharge neurological outcome (modified Rankin 4-6), and poor discharge disposition (skilled nursing facility, hospice, or inpatient death). Separate multivariable regression models assessed these relationships after adjusting for relevant covariates.

Results: Of 504 ICH patients analyzed, mean age was 67 (SD 14.9), 46% were female, and median baseline ICH volume was 14.6 mL (IQR 4.98-35.0). In primary analyses, female sex was not associated with ICH volume or hematoma expansion but was associated with lobar ICH location (adjusted OR 1.72, 95% CI: 1.09-2.70). In secondary analyses, female sex was not associated with poor discharge neurological outcomes (adjusted OR 1.40, 95% CI: 0.74-2.64) after adjusting for race, ICH severity, and ICH location. However, there was an association of female sex with poor discharge disposition (adjusted OR 1.91, 95% CI: 1.15-3.16) after adjusting for similar covariates.

Conclusions: While there were no clear intergroup sex differences in ICH severity or neurological outcomes, female sex was associated with worse discharge disposition. Further work is required to clarify whether these disposition differences are due to disease specific complications, characteristics, or if there are other social disparities responsible for these outcome differences.

Abstract WP188: Relationships Of Hematocrit With Asymptomatic And Symptomatic Lacunar Ischemic Lesions

Introduction: Hematocrit at both low and high extremes can result in both hypoxia and thrombosis respectively. While both scenarios may predispose to ischemia, it is unclear whether hematocrit associates with small vessel cerebrovascular lacunar infarcts.

Hypothesis: Hematocrit levels will associate with both asymptomatic and symptomatic cerebrovascular lacunar infarcts in stroke-free participants and ischemic stroke patients, respectively.

Methods: A cross sectional observational analysis of a prospective, population-based cohort study of stroke-free, older adult (>50) participants from the Northern Manhattan study (NOMAS) receiving baseline hematocrit testing and MRI between 2003-2008 were analyzed. A second, single center prospective cohort of admitted adult ischemic stroke patients receiving baseline hematocrit testing and MRI between 2005-2018 was evaluated. Associations of hematocrit with covert, asymptomatic chronic lacunar infarcts from stroke-free participants in NOMAS were assessed using general additive models after adjusting for relevant covariates. Separate analyses were performed to assess associations of hematocrit with symptomatic acute lacunar infarct stroke etiology using similar adjusted models for patients admitted and enrolled into the ischemic stroke registry.

Results: Of 1218 NOMAS participants analyzed, 6% had covert chronic lacunar infarcts. The association between hematocrit and covert chronic lacunar infarcts was U-shaped (X2: 9.21; p-value: 0.03). In the 1489 patients from the ischemic stroke registry, 23% were identified to have symptomatic acute lacunar infarcts. Linear relationships were identified with higher hematocrit and symptomatic acute lacunar infarct etiology (adjusted coefficient beta: 0.020; standard error: 0.009; p=0.03).

Conclusions: We identified relationships of hematocrit with both asymptomatic and symptomatic lacunar infarcts in both stroke-free and ischemic stroke cohorts, respectively. There may be a relevant role of red blood cell volumes with ischemic cerebral small vessel disease pathophysiology. However, further studies are required to clarify the mechanisms behind these relationships.

Abstract TP125: Relationships Of Female Sex With Viscoelastic Hemostatic Assay Coagulation Characteristics After Intracerebral Hemorrhage

Introduction: There are described differences in coagulation between females and males. Specifically, female sex is associated with greater platelet activation and stronger clotting characteristics. It is unclear whether there are relevant coagulation differences identifiable between female and male patients suffering from intracerebral hemorrhage (ICH).

Hypothesis: Female sex will be associated with stronger clotting characteristics on whole blood viscoelastic hemostatic assay testing.

Methods: Spontaneous ICH patients admitted and enrolled into a prospective observational ICH cohort study between 2009-2020 and who received baseline viscoelastic hemostatic assay testing (Rotational Thromboelastometry: ROTEM) were assessed. Patients with prior anticoagulant use, patients receiving hemorrhage control therapies prior to ROTEM, and secondary etiologies of ICH were excluded from the analysis. Female sex was assessed as the primary exposure variable. The following ROTEM clotting parameters were assessed as the outcome: Coagulation Time (CT) and Maximum Clot Firmness (MCF). We assessed relationships of female sex with these separate ROTEM parameters using multivariable linear regression analyses after adjusting for relevant covariates.

Results: Of 57 ICH patients included for analyses, mean age was 65 (SD 14.1), 47% were female, and the median ICH volume was 20.6 mL (IQR 10.1-43.3). There were no baseline intergroup sex differences in demographics, age, or ICH characteristics. Female sex was associated with increased EXTEM MCF (ß 0.323, p<0.05), signifying greater clotting strength, after adjusting for age, race, baseline hematoma volume, and ICH location. Female sex was not associated with other ROTEM parameters.

Conclusions: We identified that female sex was associated with stronger clotting characteristics on ROTEM viscoelastic testing. Further work is required to clarify the clinical significance of these findings and their potential specific impacts on radiographic, complication, and clinical outcomes after ICH.

Location Matters: Navigating Regional Heterogeneity of the Neurovascular Unit

The neurovascular unit (NVU) of the brain is composed of multiple cell types that act synergistically to modify blood flow to locally match the energy demand of neural activity, as well as to maintain the integrity of the blood-brain barrier (BBB). It is becoming increasingly recognized that the functional specialization, as well as the cellular composition of the NVU varies spatially. This heterogeneity is encountered as variations in vascular and perivascular cells along the arteriole-capillary-venule axis, as well as through differences in NVU composition throughout anatomical regions of the brain. Given the wide variations in metabolic demands between brain regions, especially those of gray vs. white matter, the spatial heterogeneity of the NVU is critical to brain function. Here we review recent evidence demonstrating regional specialization of the NVU between brain regions, by focusing on the heterogeneity of its individual cellular components and briefly discussing novel approaches to investigate NVU diversity.

Microbiological surveillance of endoscopes and implications for current reprocessing procedures adopted by an Italian teaching hospital

BACKGROUND

Hospital acquired infections have been associated with the contamination of flexible endoscopes caused by a failure of the reprocessing procedure. Microbiological surveillance of endoscope reprocessing is valuable for assessing contamination by pathogens. The aim of this study is to evaluate microbiological contamination of endoscopes after reprocessing, and the involvement of reprocessing procedures adopted in endoscopy units of an Italian teaching-hospital.

METHODS

The study was carried out, on several dates in 2014, in 11 endoscopic operation units equipped with 100 endoscopes (18 bronchoscopes, 41 gastroduodenoscopes, 29 colonoscopes, 12 laryngoscopes) and 9 Automated Endoscope Reprocessors. Presence/absence of common pathogens and indicator micro-organisms (including multi-drug resistant bacteria) and Total Microbiological Count (TMC) were obtained from the biopsy channels of endoscopes after reprocessing, from final rinse water of automated endoscope reprocessors and from tap water applying standard microbiological culture methods. Following the European Guidelines for quality assurance in reprocessing, the post-reprocessing criteria were "absence of indicator micro-organisms and absence of TMC in samples obtained from endoscopes' channels".

RESULTS

A total of 180 samples were collected (143 endoscopes, 25 Automated Endoscope Reprocessors and 12 water supply). Compliance to the European Guidelines was achieved for 112 out of the 180 (62.2%) samples analyzed. Presence of indicator micro-organisms (mainly Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and other Gram-negative non-fermenting bacteria) was found in 51 out of 143 endoscopes (35.7%). Multi-drug resistant bacteria were also found. Presence of pathogen micro-organisms was statistically associated with the increase of TMC level, but not with time after reprocessing.

CONCLUSION

The study provides information about the microbiological quality of endoscope reprocessing procedures adopted by different endoscopic operation units. The high prevalence of contaminated endoscopes provides evidence of the need to improve the quality of reprocessing.

Fgfbp1 promotes blood-brain barrier development by regulating collagen IV deposition and maintaining Wnt/β-catenin signaling

Central nervous system (CNS) blood vessels contain a functional blood-brain barrier (BBB) that is necessary for neuronal survival and activity. Although Wnt/β-catenin signaling is essential for BBB development, its downstream targets within the neurovasculature remain poorly understood. To identify targets of Wnt/β-catenin signaling underlying BBB maturation, we performed a microarray analysis that identified Fgfbp1 as a novel Wnt/β-catenin-regulated gene in mouse brain endothelial cells (mBECs). Fgfbp1 is expressed in the CNS endothelium and secreted into the vascular basement membrane during BBB formation. Endothelial genetic ablation of Fgfbp1 results in transient hypervascularization but delays BBB maturation in specific CNS regions, as evidenced by both upregulation of Plvap and increased tracer leakage across the neurovasculature due to reduced Wnt/β-catenin activity. In addition, collagen IV deposition in the vascular basement membrane is reduced in mutant mice, leading to defective endothelial cell-pericyte interactions. Fgfbp1 is required cell-autonomously in mBECs to concentrate Wnt ligands near cell junctions and promote maturation of their barrier properties in vitro Thus, Fgfbp1 is a crucial extracellular matrix protein during BBB maturation that regulates cell-cell interactions and Wnt/β-catenin activity.

Multimodal surveillance of healthcare associated infections in an intensive care unit of a large teaching hospital

BACKGROUND

Healthcare-associated infections (HAIs), or nosocomial infections, represent a significant burden in terms of mortality, morbidity, length of stay and costs for patients hospitalized in intensive care units (ICUs). Surveillance systems are recommended by national and international institutions to gather data on HAIs in order to develop and evaluate interventions that reduce the risk of HAIs.

STUDY DESIGN

Here we describe the methodology and the results of the surveillance system implemented in the ICU of the Policlinico Umberto I, a large teaching hospital in Rome, from April 2016 to October 2018.

METHODS

The multimodal infection surveillance system integrates four different approaches: i) active surveillance of inpatients; ii) environmental microbiological surveillance; iii) surveillance of isolated microorganisms; and iv) behavioral surveillance of healthcare personnel. Data were collected on catheter-related bloodstream infections, ventilation-associated pneumonia, catheter-associated urinary tract infections and primary bloodstream infections that developed in patients after 48 h in the ICU. For environmental surveillance 14 points were selected for sampling (i.e. bed edges, medication carts, PC keyboards, sink faucets). The system of active surveillance of HAIs also included surveillance of microorganisms, consisting of the molecular genotyping of bacterial isolates by pulsed-field gel electrophoresis (PFGE). From 1 November 2016, monitoring of compliance with guidelines for hand hygiene (HH) and proper glove or gown use by healthcare personnel was included in the surveillance system. After the first six months (baseline phase), a multimodal intervention to improve adherence to guidelines by healthcare personnel was conducted with the ICU staff.

RESULTS

Overall, 773 patients were included in the active surveillance. The overall incidence rate of device-related HAIs was 14.1 (95% CI: 12.2-16.3) per 1000 patient-days. The monthly device-related HAI incident rate showed a decreasing trend over time, with peaks of incidence becoming progressively lower. The most common bacterial isolates were Klebsiella pneumoniae (20.7%), Acinetobacter baumannii (17.2%), Pseudomonas aeruginosa (13.4%) and Staphylococcus aureus (5.4%). Acinetobacter baumannii and Klebsiella pneumoniae showed the highest proportion of isolates with a multidrug-resistant profile. A total of 819 environmental samples were collected, from which 305 bacterial isolates were retrieved. The most frequent bacterial isolates were Acinetobacter baumannii (27.2%), Staphylococcus aureus (12.1%), Enterococcus faecalis (11.1%), Klebsiella pneumoniae (5.2%) and Pseudomonas aeruginosa (4.7%). All Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae environmental isolates were at least multidrug-resistant. Genotyping showed a limited number of major PFGE patterns for both clinical and environmental isolates of Klebsiella pneumoniae and Acinetobacter baumannii. Behavioral compliance rates significantly improved from baseline to post-intervention phase.

CONCLUSIONS

By integrating information gathered from active surveillance, environmental microbiological surveillance, surveillance of bacterial isolates and behavioral surveillance of healthcare personnel, the multimodal infection surveillance system returned a precise and detailed view of the infectious risk and microbial ecology of the ICU.

Neuronal and glial regulation of CNS angiogenesis and barriergenesis

Neurovascular pathologies of the central nervous system (CNS), which are associated with barrier dysfunction, are leading causes of death and disability. The roles that neuronal and glial progenitors and mature cells play in CNS angiogenesis and neurovascular barrier maturation have been elucidated in recent years. Yet how neuronal activity influences these processes remains largely unexplored. Here, we discuss our current understanding of how neuronal and glial development affects CNS angiogenesis and barriergenesis, and outline future directions to elucidate how neuronal activity might influence these processes. An understanding of these mechanisms is crucial for developing new interventions to treat neurovascular pathologies.

Multimodal Surveillance of HAI in an Intensive Care Unit of a Large Teaching Hospital

Background

Healthcare associated Infections (HAIs) represent a significant burden in terms of mortality, morbidity, length of stay and costs for patients in intensive care units (ICU). Surveillance systems are recommended to gather data in order to elaborate and evaluate intervention to reduce HAIs risk. Here we describe results of the multimodal surveillance system implemented in the ICU of a large teaching hospital in Rome from April 2016 to October 2018.

Methods

The surveillance system integrated four different approaches: i) active surveillance focused on inpatients; ii) environmental microbiological surveillance; iii) surveillance focused on isolated microorganisms; iv) behavioral surveillance of the healthcare personnel. The system included the molecular genotyping of bacterial isolates through the pulsed field gel electrophoresis (PFGE). Moreover, an intervention to improve personnel adherence to hand hygiene (HH) guidelines was conducted.

Results

Overall, 773 patients were included in the surveillance. The global incidence rate of the device related HAIs was 14.1 (95%CI: 12.2-16.3) per 1000 patient day. Monthly device related HAIs incidence rate showed a decreasing, from 26.9 per 1000 patient day in October 2016, to 4.9 in September 2018. The most common bacterial isolate was K. pneumoniae (20.7%), the 94.0% of which were multidrug-resistant. A total of 305 environmental bacterial isolates were retrieved and the most frequent was A. baumannii (27.2%), that was always multidrug-resistant. Genotyping showed a limited number of major PFGE patters in clinical and environmental isolates. Behavioral compliance to HH guidelines improved after the educational intervention.

Conclusions

The data showed an overall slight decrease over time of the adjusted risk HAIs rates. Through the integration of information gathered from the four approaches, the application of this model returns a precise and detailed view of the infectious risk and of the microbial ecology of the ICU.

Key messages

Multimodal surveillance systems are effective to monitor HAI incidence and to determine the infectious risk. Genotyping techniques allows to characterize and link the clinical and environmental isolates.

Prophylactic TLR9 stimulation reduces brain metastasis through microglia activation

Brain metastases are prevalent in various types of cancer and are often terminal, given the low efficacy of available therapies. Therefore, preventing them is of utmost clinical relevance, and prophylactic treatments are perhaps the most efficient strategy. Here, we show that systemic prophylactic administration of a toll-like receptor (TLR) 9 agonist, CpG-C, is effective against brain metastases. Acute and chronic systemic administration of CpG-C reduced tumor cell seeding and growth in the brain in three tumor models in mice, including metastasis of human and mouse lung cancer, and spontaneous melanoma-derived brain metastasis. Studying mechanisms underlying the therapeutic effects of CpG-C, we found that in the brain, unlike in the periphery, natural killer (NK) cells and monocytes are not involved in controlling metastasis. Next, we demonstrated that the systemically administered CpG-C is taken up by endothelial cells, astrocytes, and microglia, without affecting blood-brain barrier (BBB) integrity and tumor brain extravasation. In vitro assays pointed to microglia, but not astrocytes, as mediators of CpG- C effects through increased tumor killing and phagocytosis, mediated by direct microglia-tumor contact. In vivo, CpG-C-activated microglia displayed elevated mRNA expression levels of apoptosis-inducing and phagocytosis-related genes. Intravital imaging showed that CpG-C-activated microglia cells contact, kill, and phagocytize tumor cells in the early stages of tumor brain invasion more than nonactivated microglia. Blocking in vivo activation of microglia with minocycline, and depletion of microglia with a colony-stimulating factor 1 inhibitor, indicated that microglia mediate the antitumor effects of CpG-C. Overall, the results suggest prophylactic CpG-C treatment as a new intervention against brain metastasis, through an essential activation of microglia.

Evaluation of timing of re-appearance of VBNC Legionella for risk assessment in hospital water distribution systems

BACKGROUND

In this study we estimated the presence of Legionella species, viable but non-culturable (VBNC), in hospital water networks. We also evaluated the time and load of Legionella appearance in samples found negative using the standard culture method.

METHODS

A total of 42 samples was obtained from the tap water of five hospital buildings. The samples were tested for Legionella by the standard culture method and were monitored for up to 12 months for the appearance of VBNC Legionella.

RESULTS

All the 42 samples were negative at the time of collection. Seven of the 42 samples (17.0%) became positive for Legionella at different times of monitoring. The time to the appearance of VBNC Legionella was extremely variable, from 15 days to 9 months from sampling. The most frequent Legionella species observed were Legionella spp and L. anisa and only in one sample L. pneumophila srg.1.

CONCLUSIONS

Our study confirms the presence of VBNC Legionella in samples resulting negative using the standard culture method and highlights the different time to its appearance that can occur several months after sampling. The results are important for risk assessment and risk management of engineered water systems.

Non Tuberculous Cutaneous Mycobacteriosis in a primary school in Rome: epidemiological and microbiological investigation

During the school years 2009-2010 and 2010-2011 a total of 25 cases of Non Tuberculous Cutaneous Mycobacteriosis (NTCM) were notified in children attending the same school with a swimming pool in Rome. Environmental microbiological and epidemiological investigations (only for suspected outbreaks in 2009-2010) were conducted. We screened students with skin lesions, and environmental samples were collected from the school area and the swimming pool. During the school year 2009-10 18 cases were clinically identified among 514 primary school children (3.50%) and all cases attended the swimming pool. Only 2 out of 18 cultures were positive for Mycobacterium chelonae complex (Group III, M. abscessus). Attack Rate for swimming pool use was 13,10% (17/130), with a Relative Risk 54,70 (95% CI: 9,4 - ∞). In February 2011 additional 7 cases of cutaneous NTM among children - who attended the same primary school and swimming pool were notified to the local public health authority followed by environmental microbiological investigation. Environmental samples were positive for NTM but not for M. abscessus. Mycobacteria are not included in water-quality criteria in Italy for this reason it is important to collect evidences of NTM cases caused by these infrequent pathogens, to be able to perform rapid risk assessment and to identify the best practices in prevention and management of such a risk.

In vivo effect of an immunostimulating bacterial lysate on human B lymphocytes

The aim of the present study is to investigate in humans the mechanism by which the oral vaccine Polyvalent Mechanical Bacterial Lysate (PMBL) can rapidly mobilize specific immune response and evaluate the efficacy of its immunostimulating activity in preventing recurrent infections of the upper respiratory tract (URTIs) in a group of patients with a medical history of URTI recurrence. Patients received, by sublingual route, PBML, an immunostimulating lysate obtained by mechanical lysis of the most common bacteria responsible for upper respiratory tract infections. The treatment was administered for 10 consecutive days/month for 3 consecutive months. After the end of the treatment period the patients were followed up for an additional 3 months. The frequency of IgM memory B cells and the expression of the activation marker CD25 in peripheral blood lymphocytes were measured using the flow cytometric method before the start and at days 30 and 90 of the treatment cycle. To correlate clinical results to immunological parameters, the patients were monitored at different time-points during the treatment and at the end of follow-up period. The results showed that PMBL exerts a therapeutic and preventing effect in acute and recurrent infections of the upper respiratory tract and that this effect correlated with the activation and enhancement of both IgM memory B lymphocytes (CD24+/CD27+ cells) and IL2 receptor-expressing lymphocytes (CD25+ cells) involved either in humoral or cellular immunity.

Effect of resveratrol on proliferation and telomerase activity of human colon cancer cells in vitro

A number of studies performed in our laboratory and elsewhere, showed that resveratrol is able to prevent carcinogenesis and to impair tumor growth and progression. In order to provide additional information on the pleiotropic effects of resveratrol on malignant cells, the present study was performed to test the in vitro influence of the compound on the growth and TLMA of HT-29 and WiDr human colon cancer cell lines. The results confirmed that resveratrol has a direct, dose dependent, inhibitory effect on cell proliferation in both lines. In addition, for the first time, relatively high concentrations of this compound were found to be able to substantially down-regulate telomerase activity. These preliminary results further support the potential role of resveratrol in chemoprevention/chemotherapy of human colon tumor cells and provide the rational basis for novel strategies in cancer control.

Effect of resveratrol on proliferation and telomerase activity of human colon cancer cells in vitro

A number of studies performed in our laboratory and elsewhere, showed that resveratrol is able to prevent carcinogenesis and to impair tumor growth and progression. In order to provide additional information on the pleiotropic effects of resveratrol on malignant cells, the present study was performed to test the in vitro influence of the compound on the growth and TLMA of HT-29 and WiDr human colon cancer cell lines. The results confirmed that resveratrol has a direct, dose dependent, inhibitory effect on cell proliferation in both lines. In addition, for the first time, relatively high concentrations of this compound were found to be able to substantially down-regulate telomerase activity. These preliminary results further support the potential role of resveratrol in chemoprevention/chemotherapy of human colon tumor cells and provide the rational basis for novel strategies in cancer control.

Effect of morphine on cell-mediated immune responses of human lymphocytes against allogeneic malignant cells

Opioid drugs, including morphine, are largely used as pain control in cancer patients at different stages of neoplastic growth and progression. Therefore, the possible influence of these drugs on host immunity appears to be of considerable interest. We have examined in vitro the effect of morphine on the generation of human cytotoxic T lymphocytes (CTL) against HTLV-I induced T-cell leukemia cells (MT-2 line). The results show that the drug, at graded concentrations (from 3 pg/ml to 32 microg/ml), that include those detectable in treated patients, enhances CTL activity whereas natural killer cell activity was unaffected. The enhancing effect is particularly evident when morphine was present at the onset of lymphocyte/MT-2 co-culture. On the contrary, the drug was ineffective when added on the last day of co-culture, thus indicating that morphine operates during the generation phase of CTL, but not on mature CTL. Flow cytometric analysis of intracellular cytokine expression showed that morphine increases the percentage of interferon gamma-producing CD8+ T cells in co-culture assay. Collectively, these results suggest that in our experimental model morphine enhances CTL responses by directly affecting the induction phase of T-dependent cell-mediated immunity.

Preclinical studies on detection of circulating melanoma cells in patients: telomerase as a recognition marker of malignancy

Preclinical studies based on a "simulation design", were performed with cultured melanoma cells prelabeled with 51Cr, added to normal blood and subjected to separation and recognition steps. Mononuclear cells (MNC) were isolated on ficollhypaque gradient, and melanoma cells were separated from lymphocytes using anti-CD45 immunomagnetic beads. Malignant cells were then recognized by measuring telomerase activity (TRAP and TRAP-ELISA assays). It was found that: (a)recovery of prelabeled cells present in MNC did not exceed 75%; (b) further recovery of prelabeled cells after separation from lymphocytes did not exceed 68%. Therefore, the overall recovery of prelabeled cells did not exceed 48%; (c) the entire procedure was able to reliably detect as few as 30 malignant cells added to normal blood, providing a telomerase signal significantly higher than that found in absence of melanoma cells. These results furnish the technical bases for developing a tumor detection assay in the blood of melanoma patients.

Drug-induced modulation of carcinoembryonic antigen (CEA) expression in neoplastic cells from a patient with rectal cancer

Treatment with 5-fluorouracil (5-FU) or recombinant interferon-gamma (IFN), alone or in combination, was found to increase carcinoembryonic antigen (CEA) expression in several carcinoma cell lines. In this study we examined the in vitro effect of these agents on CEA expression of tumor cells, obtained from a patient operated for rectal cancer. The results showed that exposure of cancer cells to 5-FU or to IFN resulted in increased CEA levels in terms of percentage of CEA-positive cells and mean fluorescence values, as indicated by FACS analysis. However, drug combination did not induce CEA expression higher than that provided by single agents alone. Treatment with 5-FU or with IFN produced a reduction of the total number of viable cells. Moreover, Western blot analysis revealed that exposure of cancer cells to each drug was followed by a substantial increase of the total cellular CEA content. On the contrary, 5-FU in combination with IFN did not increase the expression of the antigen more than that obtained by single agents. Noteworthy, exposure of CEA-negative cells from adjacent normal rectal tissue to both agents alone or in combination, did not result in CEA induction. In conclusion, the present results suggest new approaches aimed at (a) increasing the sensitivity of diagnostic procedures based on detection of CEA-positive tumor cells; (b) facilitating the recognition of CEA-positive cancer cells by immune responses induced by anti-CEA peptide vaccines.