Septic encephalopathy and septic encephalitis‬‬

Septic encephalopathy in the elderly - biomarkers of potential clinical utility

Next to acute sickness behavior, septic encephalopathy is the most frequent involvement of the brain during infection. It is characterized by a cross-talk of pro-inflammatory cells across the blood-brain barrier, by microglial activation and leukocyte migration, but not by the entry of infecting organisms into the brain tissue. Septic encephalopathy is very frequent in older persons because of their limited cognitive reserve. The predominant clinical manifestation is delirium, whereas focal neurological signs and symptoms are absent. Electroencephalography is a very sensitive method to detect functional abnormalities, but these abnormalities are not specific for septic encephalopathy and of limited prognostic value. Routine cerebral imaging by computer tomography usually fails to visualize the subtle abnormalities produced by septic involvement of the brain. Magnetic resonance imaging is by far more sensitive to detect vasogenic edema, diffuse axonal injury or small ischemic lesions. Routine laboratory parameters most suitable to monitor sepsis, but not specific for septic encephalopathy, are C-reactive protein and procalcitonin. The additional measurement of interleukin (IL)-6, IL-8, IL-10 and tumor necrosis factor-α increases the accuracy to predict delirium and an unfavorable outcome. The most promising laboratory parameters to quantify neuronal and axonal injury caused by septic encephalopathy are neurofilament light chains (NfL) and S100B protein. Neuron-specific enolase (NSE) plasma concentrations are strongly influenced by hemolysis. We propose to determine NSE only in non-hemolytic plasma or serum samples for the estimation of outcome in septic encephalopathy.

Treatment of septic encephalopathy and encephalitis - a critical appraisal

INTRODUCTION

The central nervous system is frequently involved during severe sepsis. Patients either develop septic encephalopathy characterized by delirium and coma or focal neurological signs as a consequence of septic-embolic or septic-metastatic encephalitis.

AREAS COVERED

In this review, a summary of currently available literature on established and some promising experimental treatment options for septic encephalopathy and encephalitis is provided, with a focus on the clinical utility of published studies.

EXPERT OPINION

Treatment relies on proper identification of the causative pathogen and rapidly initiated adequate empirical or (after identification of the pathogen) tailored antibiotic therapy, fluid and electrolyte management. In the presence of brain abscess(es) or mycotic aneurysm(s), surgery or interventional neuroradiology must be considered. Pharmacological approaches to prevent delirium of different etiology include the use of dexmedetomidine and (with limitations) of melatonin and its derivatives. In the absence of a specific pharmacological treatment, non-pharmacological bundles of interventions (e.g. promotion of sleep, cognitive stimulation, early mobilization and adequate therapy of pain) are of proven efficacy to prevent delirium of different etiology including sepsis. Experimental promising therapies include the use of non-bacteriolytic antibiotics and the reduction of the toxic effects of microglial activation.

Sodium tanshinone IIA sulfonate attenuates sepsis-associated brain injury via inhibiting NOD-like receptor 3/caspase-1/gasdermin D-mediated pyroptosis

BACKGROUND

Sodium tanshinone IIA sulfonate (STS) has been reported to protect organ function in sepsis. However, the attenuation of sepsis-associated brain injury and its underlying mechanisms by STS has not been established.

METHODS

C57BL/6 mice were used to establish the cecal ligation perforation (CLP) model, and STS was injected intraperitoneally 30 min before the surgery. The BV2 cells were stimulated by lipopolysaccharide after being pre-treated with STS for 4 h. The STS protective effects against brain injury and in vivo anti-neuroinflammatory effects were investigated using the 48-hour survival rate and body weight changes, brain water content, histopathological staining, immunohistochemistry, ELISA, RT-qPCR, and transmission electron microscopy. The pro-inflammatory cytokines of BV2 cells were detected by ELISA and RT-qPCR. At last, the levels of NOD-like receptor 3 (NLRP3) inflammasome activation and pyroptosis in brain tissues of the CLP model and BV2 cells were detected using western blotting.

RESULTS

STS increased the survival rate, decreased brain water content, and improved brain pathological damage in the CLP models. STS increased the expressions of tight junction proteins ZO-1 and Claudin5 while reducing the expressions of tumor necrosis factor α (TNF-α), interleukin-1β(IL-1β), and interleukin-18 (IL-18) in the brain tissues of the CLP models. Meanwhile, STS inhibited microglial activation and M1-type polarization in vitro and in vivo. The NLRP3/caspase-1/ gasdermin D (GSDMD)-mediated pyroptosis was activated in the brain tissues of the CLP models and lipopolysaccharide (LPS)-treated BV2 cells, which was significantly inhibited by STS.

CONCLUSIONS

The activation of NLRP3/caspase-1/GSDMD-mediated pyroptosis and subsequent secretion of proinflammatory cytokines may be the underlying mechanisms of STS against sepsis-associated brain injury and neuroinflammatory response.

The biological alterations of synapse/synapse formation in sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a common complication caused by sepsis, and is responsible for increased mortality and poor outcomes in septic patients. Neurological dysfunction is one of the main manifestations of SAE patients. Patients may still have long-term cognitive impairment after hospital discharge, and the underlying mechanism is still unclear. Here, we first outline the pathophysiological changes of SAE, including neuroinflammation, glial activation, and blood-brain barrier (BBB) breakdown. Synapse dysfunction is one of the main contributors leading to neurological impairment. Therefore, we summarized SAE-induced synaptic dysfunction, such as synaptic plasticity inhibition, neurotransmitter imbalance, and synapses loss. Finally, we discuss the alterations in the synapse, synapse formation, and mediators associated with synapse formation during SAE. In this review, we focus on the changes in synapse/synapse formation caused by SAE, which can further understand the synaptic dysfunction associated with neurological impairment in SAE and provide important insights for exploring appropriate therapeutic targets of SAE.

Blood-Brain Barrier Disruption by Lipopolysaccharide and Sepsis-Associated Encephalopathy

As a complex multicellular structure of the vascular system at the central nervous system (CNS), the blood-brain barrier (BBB) separates the CNS from the system circulation and regulates the influx and efflux of substances to maintain the steady-state environment of the CNS. Lipopolysaccharide (LPS), the cell wall component of Gram-negative bacteria, can damage the barrier function of BBB and further promote the occurrence and development of sepsis-associated encephalopathy (SAE). Here, we conduct a literature review of the direct and indirect damage mechanisms of LPS to BBB and the relationship between these processes and SAE. We believe that after LPS destroys BBB, a large number of inflammatory factors and neurotoxins will enter and damage the brain tissue, which will activate brain immune cells to mediate inflammatory response and in turn further destroys BBB. This vicious circle will ultimately lead to the progression of SAE. Finally, we present a succinct overview of the treatment of SAE by restoring the BBB barrier function and summarize novel opportunities in controlling the progression of SAE by targeting the BBB.

Evidence of Coronavirus (CoV) Pathogenesis and Emerging Pathogen SARS-CoV-2 in the Nervous System: A Review on Neurological Impairments and Manifestations

The coronavirus disease 2019 (COVID-19) pandemic is an issue of global significance that has taken the lives of many across the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for its pathogenesis. The pulmonary manifestations of COVID-19 have been well described in the literature. Initially, it was thought to be limited to the respiratory system; however, we now recognize that COVID-19 also affects several other organs, including the nervous system. Two similar human coronaviruses (CoV) that cause severe acute respiratory syndrome (SARS-CoV-1) and Middle East respiratory syndrome (MERS-CoV) are also known to cause disease in the nervous system. The neurological manifestations of SARS-CoV-2 infection are growing rapidly, as evidenced by several reports. There are several mechanisms responsible for such manifestations in the nervous system. For instance, post-infectious immune-mediated processes, direct virus infection of the central nervous system (CNS), and virus-induced hyperinflammatory and hypercoagulable states are commonly involved. Guillain-Barré syndrome (GBS) and its variants, dysfunction of taste and smell, and muscle injury are numerous examples of COVID-19 PNS (peripheral nervous system) disease. Likewise, hemorrhagic and ischemic stroke, encephalitis, meningitis, encephalopathy acute disseminated encephalomyelitis, endothelialitis, and venous sinus thrombosis are some instances of COVID-19 CNS disease. Due to multifactorial and complicated pathogenic mechanisms, COVID-19 poses a large-scale threat to the whole nervous system. A complete understanding of SARS-CoV-2 neurological impairments is still lacking, but our knowledge base is rapidly expanding. Therefore, we anticipate that this comprehensive review will provide valuable insights and facilitate the work of neuroscientists in unfolding different neurological dimensions of COVID-19 and other CoV associated abnormalities.

Neuroradiology of infectious diseases

PURPOSE OF REVIEW

Early diagnosis of central nervous system (CNS) infections is crucial given high morbidity and mortality. Neuroimaging in CNS infections is widely used to aid in the diagnosis, treatment and to assess the response to antibiotic and neurosurgical interventions.

RECENT FINDINGS

The Infectious Diseases Society of America (IDSA) guidelines have clear recommendations for obtaining a computerized tomography of the head (CTH) prior to lumbar puncture (LP) in suspected meningitis. In the absence of indications for imaging or in aseptic meningitis, cranial imaging is of low utility. In contrast, cranial imaging is of utmost importance in the setting of encephalitis, bacterial meningitis, ventriculitis, bacterial brain abscess, subdural empyema, epidural abscess, neurobrucellosis, neurocysticercosis, and CNS tuberculosis that can aid clinicians with the differential diagnosis, source of infection (e.g., otitis, sinusitis), assessing complications of meningitis (e.g., hydrocephalus, venous sinus thrombosis, strokes), need for neurosurgical interventions and to monitor for the response of therapy. Novel imaging techniques such as fast imaging employing steady-state acquisition (FIESTA), susceptibility-weighted imaging (SWI), and chemical exchange saturation transfer (CEST) contrast are briefly discussed.

SUMMARY

Though the radiological findings in CNS infections are vast, certain patterns along with clinical clues from history and examination often pave the way to early diagnosis. This review reiterates the importance of obtaining cranial imaging when necessary, and the various radiological presentations of commonly encountered CNS infections.

SARS-CoV-2 Infection in the Central and Peripheral Nervous System-Associated Morbidities and Their Potential Mechanism

The recent outbreak of SARS-CoV-2 infections that causes coronavirus-induced disease of 2019 (COVID-19) is the defining and unprecedented global health crisis of our time in both the scale and magnitude. Although the respiratory tract is the primary target of SARS-CoV-2, accumulating evidence suggests that the virus may also invade both the central nervous system (CNS) and the peripheral nervous system (PNS) leading to numerous neurological issues including some serious complications such as seizures, encephalitis, and loss of consciousness. Here, we present a comprehensive review of the currently known role of SARS-CoV-2 and identify all the neurological problems reported among the COVID-19 case reports throughout the world. The virus might gain entry into the CNS either through the trans-synaptic route via the olfactory neurons or through the damaged endothelium in the brain microvasculature using the ACE2 receptor potentiated by neuropilin-1 (NRP-1). The most critical of all symptoms appear to be the spontaneous loss of breathing in some COVID-19 patients. This might be indicative of a dysfunction within the cardiopulmonary regulatory centers in the brainstem. These pioneering studies, thus, lay a strong foundation for more in-depth basic and clinical research required to confirm the role of SARS-CoV-2 infection in neurodegeneration of critical brain regulatory centers.

Neurophysiological findings and their prognostic value in critical COVID-19 patients: An observational study

OBJECTIVE

To describe EEG patterns of critical Coronavirus Disease 2019 (COVID-19) patients with suspicion of encephalopathy and test their association with clinical outcome.

METHODS

EEG after discontinuation of sedation in all patients, and somesthesic evoked potentials and brainstem auditive evoked potentials when EEG did not show reactivity, were performed. Clinical outcome was assessed at day 7 and 14 after neurophysiological explorations.

RESULTS

33 patients were included for analysis. We found slowed background activity in 85% of cases, unreactive activity in 42% of cases, low-voltage activity in 21% of cases and rhythmic or periodic delta waves in 61% of cases. EEG epileptic events were never recorded. Clinical outcome at day 14 was associated with unreactive background activity and tended to be associated with rhythmic or periodic delta waves and with low-voltage activity. Results of multimodal evoked potentials were in favor of a preservation of central nervous system somatosensory and auditory functions.

CONCLUSIONS

Among critical COVID-19 patients with abnormal arousal at discontinuation of sedation, EEG patterns consistent with encephalopathy are found and are predictive for short term clinical outcome.

SIGNIFICANCE

The abnormal EEG with presence of periodic discharges and lack of reactivity could be related to encephalopathy linked to COVID-19.

Lung-protective ventilation increases cerebral metabolism and non-inflammatory brain injury in porcine experimental sepsis

Background

Protective ventilation with lower tidal volumes reduces systemic and organ-specific inflammation. In sepsis-induced encephalopathy or acute brain injury the use of protective ventilation has not been widely investigated (experimentally or clinically). We hypothesized that protective ventilation would attenuate cerebral inflammation in a porcine endotoxemic sepsis model. The aim of the study was to study the effect of tidal volume on cerebral inflammatory response, cerebral metabolism and brain injury. Nine animals received protective mechanical ventilation with a tidal volume of 6 mL × kg⁻¹ and nine animals were ventilated with a tidal volume of 10 mL × kg⁻¹. During a 6-h experiment, the pigs received an endotoxin intravenous infusion of 0.25 µg × kg⁻¹ × h⁻¹. Systemic, superior sagittal sinus and jugular vein blood samples were analysed for inflammatory cytokines and S100B. Intracranial pressure, brain tissue oxygenation and brain microdialysis were sampled every hour.

Results

No differences in systemic or sagittal sinus levels of TNF-α or IL-6 were seen between the groups. The low tidal volume group had increased cerebral blood flow (p < 0.001) and cerebral oxygen delivery (p < 0.001), lower cerebral vascular resistance (p < 0.05), higher cerebral metabolic rate (p < 0.05) along with higher cerebral glucose consumption (p < 0.05) and lactate production (p < 0.05). Moreover, low tidal volume ventilation increased the levels of glutamate (p < 0.01), glycerol (p < 0.05) and showed a trend towards higher lactate to pyruvate ratio (p = 0.08) in cerebral microdialysate as well as higher levels of S-100B (p < 0.05) in jugular venous plasma compared with medium–high tidal volume ventilation.

Conclusions

Contrary to the hypothesis, protective ventilation did not affect inflammatory cytokines. The low tidal volume group had increased cerebral blood flow, cerebral oxygen delivery and cerebral metabolism together with increased levels of markers of brain injury compared with medium–high tidal volume ventilation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-021-00629-0.

Septic shock due to Escherichia coli meningoencephalitis treated with immunoglobulin-M-enriched immunoglobulin preparation as adjuvant therapy: a case report

BACKGROUND

Gram-negative bacteria are an uncommon etiology of spontaneous community-acquired adult meningitis and meningoencephalitis. Escherichia coli is a Gram-negative bacterium that is normally present in the intestinal microbial pool. Some Escherichia coli strains can cause diseases in humans and animals, with both intestinal and extraintestinal manifestations (extraintestinal pathogenic Escherichia coli) such as urinary tract infections, bacteremia with sepsis, and, more rarely, meningitis. Meningitis continues to be an important cause of mortality throughout the world, despite progress in antimicrobial chemotherapy and supportive therapy. The mortality rate fluctuates between 15% and 40%, and about 50% of the survivors report neurological sequelae. The majority of Escherichia coli meningitis cases develop as a result of hematogenous spread, with higher degrees of bacteremia also being related to worse prognosis. Cases presenting with impaired consciousness (that is, coma) are also reported to have poorer outcomes.

CASE PRESENTATION

We describe the case of a 48-year-old caucasian woman with meningoencephalitis, with a marked alteration of consciousness on admission, and septic shock secondary to pyelonephritis caused by Escherichia coli, treated with targeted antimicrobial therapy and immunoglobulin-M-enriched immunoglobulin (Pentaglobin) preparation as adjuvant therapy.

CONCLUSION

Despite the dramatic presentation of the patient on admission, the conflicting data on the use of immunoglobulins in septic shock, and the lack of evidence regarding their use in adult Escherichia coli meningoencephalitis, we obtained a remarkable improvement of her clinical condition, accompanied by partial resolution of her neurological deficits.

Systemic review of CNS involvement and its manifestations in SARS-CoV2 positive patients

Coronavirus is known to cause various systemic infections both in human and animal which are mostly mild in nature. However, recent years have seen major pandemics caused by coronavirus which are very invasive and virulent in nature. The recent SARS-CoV2 is a new addition to this list of coronavirus pandemics. So the present study was done to systematically review the CNS involvement and its manifestations in SARS-CoV2 positive patients. Systemic review of article published between 1st Dec 2019 to 31st July 2020 searched through web-based database of MEDLINE (Pubmed) and Google scholar using following keywords “COVID -19” OR “CORONAVIRUS” OR “SARS-CoV2” AND “NEUROLOGICAL” OR “CNS” OR “BRAIN”. Using the steps of systemic review eight article were selected for qualitative analysis. Majority of these article were reporting neurological symptoms among patients admitted in different wards along with others general symptoms. None of the study was specifically devoted to study the neurological manifestations and complications in SARS-CoV2 positive patients. The present study concludes that there is a scarcity of good quality research which attempts to establish the role of SARS-CoV2 infection in CNS and its manifestations. However, there are evidences that CNS involvement is present in majority of the patients. Proper documentation of theses involvement and indentification of these into mild, moderate and severe infection will help in early identification and treatment of these patients.

Neurological manifestations of coronavirus infections: role of angiotensin-converting enzyme 2 in COVID-19

AIM OF THE STUDY

In December 2019, a highly pathogenic coronavirus called SARS-CoV-2 (formerly identified as 2019-nCoV) appeared in Wuhan, China, and has since been spreading rapidly around the world. we reviewed the neurological manifestations of this infection and the potential of ACE2 in the nervous system.

MATERIALS AND METHODS

Six databases (Medline, Scopus, Embase, Web of Science, WHO, and google scholar) were searched and screened by the authors for having appropriate information about covid-19. Finally, 72 studies were identified, summarized and reviewed.

RESULT

The most specific manifestation of SARS-CoV-2 patients is pulmonary distress, and several patients admitted to intensive care units were not able to breathe spontaneously. In addition, the SARS-CoV-2 outbreak has a significant effect on nervous systems and may even lead to serious neurological damage. The neuroinvasive pathobiology is still not fully elucidated and thus the effect of CoV infections on the nervous system needs to be explored. The spike protein of the virus and the angiotensin-converting enzyme 2 (ACE2) lead to the presence of both SARS-CoV and SARS-CoV-2 in the cells and, subsequently, decreased ACE2 expression.

CONCLUSION

The therapeutic possibilities of ACE2 antibody, ACE2-derived peptides, and small molecule blockers of ACE2 include a receptor-binding domain blocking approach. Hence, future studies of ACE2 may be very helpful in discovering a therapy for SARS-CoV-2.

The neuropathological impact of COVID-19: a review

BACKGROUND

The Coronavirus disease 2019 (COVID-19) outbreak has become a challenging global issue after its emergence in December 2019. Due to the high adaptation of the virus, COVID-19 demonstrated a high transmission and infectivity potentials. Several studies demonstrated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induce deleterious neurological manifestations through interacting with the central nervous system (CNS).

MAIN BODY

The neuroinvasive potential of SARS-CoV-2 might contribute to its fatal behavior. Understanding the underlying mechanisms of this novel neuropathogen might contribute to the development of effective therapeutic strategies. The manifestations of neural damage in COVID-19 patients ranged from headache to severe encephalopathy and progression of preexisting neural disorders, it is speculated that neuroinvasion is strongly linked to the fatal respiratory dysfunction. The underlying neuropathological impact of emerging pneumonia (COVID-19) is still unclear.

CONCLUSION

This review demonstrated the urgent need to understand the neuropathology of COVID-19, to manage the current borderless viral outbreak of SARS-CoV-2 and its comorbidities. Moreover, SARS-CoV-2 could be regarded as an opportunistic neuropathogen that affects several vital functions in the human body.

Impact of ambient temperature on inflammation-induced encephalopathy in endotoxemic mice-role of phosphoinositide 3-kinase gamma

BACKGROUND

Sepsis-associated encephalopathy (SAE) is an early and frequent event of infection-induced systemic inflammatory response syndrome. Phosphoinositide 3-kinase γ (PI3Kγ) is linked to neuroinflammation and inflammation-related microglial activity. In homeotherms, variations in ambient temperature (Ta) outside the thermoneutral zone lead to thermoregulatory responses, mainly driven by a gradually increasing sympathetic activity, and may affect disease severity. We hypothesized that thermoregulatory response to hypothermia (reduced Ta) aggravates SAE in PI3Kγ-dependent manner.

METHODS

Experiments were performed in wild-type, PI3Kγ knockout, and PI3Kγ kinase-dead mice, which were kept at neutral (30 ± 0.5 °C) or moderately lowered (26 ± 0.5 °C) Ta. Mice were exposed to lipopolysaccharide (LPS, 10 μg/g, from Escherichia coli serotype 055:B5, single intraperitoneal injection)-evoked systemic inflammatory response (SIR) and monitored 24 h for thermoregulatory response and blood-brain barrier integrity. Primary microglial cells and brain tissue derived from treated mice were analyzed for inflammatory responses and related cell functions. Comparisons between groups were made with one-way or two-way analysis of variance, as appropriate. Post hoc comparisons were made with the Holm-Sidak test or t tests with Bonferroni's correction for adjustments of multiple comparisons. Data not following normal distribution was tested with Kruskal-Wallis test followed by Dunn's multiple comparisons test.

RESULTS

We show that a moderate reduction of ambient temperature triggers enhanced hypothermia of mice undergoing LPS-induced systemic inflammation by aggravated SAE. PI3Kγ deficiency enhances blood-brain barrier injury and upregulation of matrix metalloproteinases (MMPs) as well as an impaired microglial phagocytic activity.

CONCLUSIONS

Thermoregulatory adaptation in response to ambient temperatures below the thermoneutral range exacerbates LPS-induced blood-brain barrier injury and neuroinflammation. PI3Kγ serves a protective role in suppressing release of MMPs, maintaining microglial motility and reinforcing phagocytosis leading to improved brain tissue integrity. Thus, preclinical research targeting severe brain inflammation responses is seriously biased when basic physiological prerequisites of mammal species such as preferred ambient temperature are ignored.

Neurological Involvement in COVID-19 Patients: A Narrative Review

Background  Coronavirus disease 2019 (COVID-19) is a viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belonging to the coronavirus family. The primary target of SARS-CoV-2 is peripheral mucosal cells of respiratory tract. Recent days have seen few cases where virus has affected extrapulmonary organ such as nervous system. Materials and Methods  The present study was a narrative review done using techniques of systemic review, that is, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases such as PubMed (Medline) and Google Scholar were searched systematically for published article from December 1, 2019 to June 5, 2020. A total of 189 articles were initially selected by the authors. A final list of 17 articles was prepared and following information were extracted from selected studies: study design, main result, and limitations of the study. Results  Majority of these article were descriptive studies describing spectrum of signs and symptoms among admitted patients. In majority of these studies, patients have developed symptoms suggestive of neurological involvement. Most common central nervous system symptoms reported were headache, followed by dizziness and confusion. Similarly, the most common peripheral nervous system involvement was loss of taste and smell. Conclusion  The present study concludes that there are enough evidences to prove that SARS-CoV-2 infection affects both central and peripheral nervous system. Various mechanisms are proposed to explain the pathophysiology of neurological manifestations in COVID-19-positive patients that needs to be established and verified.

Headache as a Cardinal Symptom of Coronavirus Disease 2019: A Cross-Sectional Study

Objective

To describe the semiology of pain and its associated features in patients with coronavirus disease 2019 (COVID‐19) and headache presenting to the emergency department who do not require urgent services.

Background

Headache is one of the most frequent neurological symptoms reported in case series, epidemiological studies, and meta‐analyses of COVID‐19, with a prevalence ranging from 8 to 71.1%. Studies addressing the semiology of these headaches are lacking.

Methods

We conducted a cross‐sectional study in the emergency department of a tertiary hospital. Patients classified according to the Manchester Triage System as standard and non‐urgent and those fulfilling the criteria for probable or confirmed COVID‐19 according to World Health Organization guidelines who presented with headache were included. A standardized questionnaire was used for data collection.

Results

Of the 145 confirmed and probable COVID‐19 patients, 99 (68.3%) reported headache. A total of 54/99 (54.5%) were classified with probable COVID‐19 and 45/99 (45.5%) with confirmed COVID‐19. The mean age (44.7 ± 11.8 vs 40.4 ± 10.7, P = .061), sex distribution (35/54 [64.8%] vs 28/45 [62.2%] female, P = .768), and headache comorbidity (19/54 [35.2%] vs 17/45 [37.8%], P = .789) were similar between the probable and confirmed COVID‐19 groups, along with other medical comorbidities and laboratory data. Patients with confirmed COVID‐19 showed a higher incidence of anosmia (21/54 [38.9%] vs 28/45 [62.2%], P = .021) and pneumonia (10/54 [18.5%] vs 18/45 [40%], P = .018), headache at onset (32/54 [59.3%] vs 39/45 [86.7%], P = .002), and hospital admission (0/54 [0%] vs 2/45 [11.1%], P = .017). In most cases, the headache appeared simultaneously with other COVID‐19 symptoms (57/99, 57.6%). It was bilateral (86/99, 86.9%), frontal or holocranial (34/99, 34.3% each) in location and intense (60/99, 60.6%, reported a visual analog scale [VAS] score ≥7). A total of 39/99 (39.4%) identified triggers, most commonly fever. The most frequent aggravating factors were physical activity (45/99, 45.5%) and coughing (43/99, 43.4%). Patients showed a propensity toward prostration (41/99, 41.4%), photophobia (29/99, 29.3%), and phonophobia (27/99, 27.3%). Partial (53/99, 53.5%) or total (26/99, 26.3%) responses to first‐step analgesics were reported. A total of 25/99 (25.3%) patients had a prior history of migraine, presenting with headache different from the usual in 23/25 (92.0%) patients. Individuals with migraine were more likely to have earlier (headache at onset of the respiratory symptoms in 24/25 [96.0%] vs 57/74 [77.0%], P = .023 [95% CI: 0.067, 0.313]), longer (>24 hours of pain in 20/25 [80%] vs 25/74 [33.8%], P < .001 [95% CI: 0.272, 0.652]), and more intense (VAS score ≥5 in 25/25 [100%] vs 63/74 [85.1%], P = .043 [95% CI: 0.057, 0.213]) headaches than patients without migraine.

Conclusions

Headache is a very prevalent COVID‐19 symptom among patients presenting to the emergency room, most frequently presenting as holocranial or bifrontal moderate to severe, and pressing quality headache. Individuals with migraine tend to present with earlier, longer, and more intense headaches.

Sepsis-associated encephalopathy and septic encephalitis: an update

INTRODUCTION

Sepsis-associated encephalopathy (SAE) and septic encephalitis (SE) are associated with increased mortality, long-term cognitive impairment, and focal neurological deficits.

AREAS COVERED

The PUBMED database was searched 2016-2020. The clinical manifestation of SAE is delirium, SE additionally is characterized by focal neurological symptoms. SAE is caused by inflammation with endothelial/microglial activation, increase of permeability of the blood-brain-barrier, hypoxia, imbalance of neurotransmitters, glial activation, axonal, and neuronal loss. Septic-embolic (SEE) and septic-metastatic encephalitis (SME) are characterized by focal ischemia (SEE) and small abscesses (SME). The continuum between SAE, SME, and SEE is documented by imaging techniques and autopsies. The backbone of treatment is rapid optimum antibiotic therapy. Experimental approaches focus on modulation of inflammation, stabilization of the blood-brain barrier, and restoration of membrane/mitochondrial function.

EXPERT OPINION

The most promising diagnostic approaches are new imaging techniques. The most important measure to fight delirium remains establishment of daily structure and adequate sensory stimuli. Dexmedetomidine and melatonin appear to reduce the frequency of delirium, their efficacy in SAE and SE remains to be established. Drugs already licensed for other indications or available as food supplements which may be effective in SAE are statins, L-DOPA/benserazide, β-hydroxybutyrate, palmitoylethanolamide, and tetracyclines or other bactericidal non-lytic antibiotics.

Mitochondrial Function in the Kidney and Heart, but Not the Brain, is Mainly Altered in an Experimental Model of Endotoxaemia

Significant impairments in mitochondrial function are associated with the development of multi-organ failure in sepsis/endotoxaemia, but the data on the dynamics of simultaneous mitochondrial impairment in multiple organs are limited. The aim of this study was to evaluate the changes in heart, brain and kidney mitochondrial function in an experimental model of lipopolysaccharide (LPS)-induced endotoxaemia.Samples were collected 4 and 24 h after single injection of LPS (10 mg/kg) in mice. Marked increases in inflammation-related gene expression were observed in all studied tissues 4 h after LPS administration. At 24 h post LPS administration, this expression of inflammation-related genes remained upregulated only in kidneys. Significantly increased concentrations of kidney function markers confirmed that kidneys were severely damaged. Echocardiographic measurements showed that the ejection fraction and fractional shortening were significantly reduced 4 h after LPS administration, whereas 24 h after LPS administration, the cardiac function was restored to baseline. A two-fold decrease in mitochondrial oxidative phosphorylation (OXPHOS) capacity in the kidney was observed 4 and 24 h after LPS administration. Significant decrease in mitochondrial fatty acid oxidation was observed in heart 4 h after LPS administration. Furthermore, 24 h after LPS administration, the respiration rates in cardiac fibers at OXPHOS and electron transport (ET) states were significantly increased, which resulted in increased ET coupling efficiency in the LPS-treated group, whereas four-fold increases in the H2O2 production rate and H2O2/O ratio were observed. The brain mitochondria demonstrated a slightly impaired mitochondrial functionality just 24 h after the induction of endotoxaemia.In conclusion, among studied tissues kidney mitochondria are the most sensitive to endotoxaemia and do not recover from LPS-induced damage, whereas in brain, mitochondrial function was not significantly altered. In heart, endotoxaemia induces a decrease in the mitochondrial fatty acid oxidation capacity, but during the phase of suppressed inflammatory response, the ET efficiency is improved despite the marked increase in reactive oxygen species production.

Cerebrospinal fluid features in SARS-CoV-2 RT-PCR positive patients

This study analyzed the cerebrospinal fluid features of 31 COVID-19 patients with neurological complications. We observed neither SARS-CoV-2 RNA in the cerebrospinal fluid, nor intrathecal IgG synthesis, but did observe signs of blood-brain barrier disruption. These results might serve as a basis for a better understanding of SARS-CoV-2 related neuropathogenesis.

Psychiatric face of COVID-19

The Coronavirus Disease 2019 (COVID-19) represents a severe multiorgan pathology which, besides cardio-respiratory manifestations, affects the function of the central nervous system (CNS). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), similarly to other coronaviruses demonstrate neurotropism; the viral infection of the brain stem may complicate the course of the disease through damaging central cardio-respiratory control. The systemic inflammation as well as neuroinflammatory changes are associated with massive increase of the brain pro-inflammatory molecules, neuroglial reactivity, altered neurochemical landscape and pathological remodelling of neuronal networks. These organic changes, emerging in concert with environmental stress caused by experiences of intensive therapy wards, pandemic fears and social restrictions, promote neuropsychiatric pathologies including major depressive disorder, bipolar disorder (BD), various psychoses, obsessive-compulsive disorder and post-traumatic stress disorder. The neuropsychiatric sequelae of COVID-19 represent serious clinical challenge that has to be considered for future complex therapies.

Automated diagnosis of encephalitis in pediatric patients using EEG rhythms and slow biphasic complexes

Slow biphasic complexes (SBC) have been identified in the EEG of patients suffering for inflammatory brain diseases. Their amplitude, location and frequency of appearance were found to correlate with the severity of encephalitis. Other characteristics of SBCs and of EEG traces of patients could reflect the grade of pathology. Here, EEG rhythms are investigated together with SBCs for a better characterization of encephalitis. EEGs have been acquired from pediatric patients: ten controls and ten encephalitic patients. They were split by neurologists into five classes of different severity of the pathology. The relative power of EEG rhythms was found to change significantly in EEGs labeled with different severity scores. Moreover, a significant variation was found in the last seconds before the appearance of an SBC. This information and quantitative indexes characterizing the SBCs were used to build a binary classification decision tree able to identify the classes of severity. True classification rate of the best model was 76.1% (73.5% with leave-one-out test). Moreover, the classification errors were among classes with similar severity scores (precision higher than 80% was achieved considering three instead of five classes). Our classification method may be a promising supporting tool for clinicians to diagnose, assess and make the follow-up of patients with encephalitis.

Metformin Attenuates Brain Injury by Inhibiting Inflammation and Regulating Tight Junction Proteins in Septic Rats

OBJECTIVE

Metformin has a potent inhibitory activity against inflammation and oxidative stress, which inevitably occur in sepsis-associated encephalopathy (SAE). The precise mechanisms underlying neuroprotective effects of metformin in SAE, are still unclear. In the present work, the protective effect of metformin on SAE using cecal ligation and puncture (CLP) model of sepsis, was assessed.

MATERIALS AND METHODS

In this experimental study, CLP procedure was performed in Wistar rats and 50 mg/kg metformin was administered immediately. Specific markers of sepsis severity, inflammation, blood brain barrier (BBB) dysfunction, and brain injury, were investigated. Specific assay kits and real-time polymerase chain reaction (RT-PCR) were used. Histopathological assessment was also carried out.

RESULTS

Treatment with metformin decreased murine sepsis score (MSS), lactate, platelet lymphocyte ratio (PLR), and high mobility group box (HMGB1) levels. The expression levels of claudin 3 (Cldn3) and claudin 5 (Cldn5) were increased following treatment with metformin. Metformin decreased the expression of S100b, neuron specific enolase (Nse), and glial fibrillary acidic protein (Gfap).

CONCLUSION

Our study suggests that metformin may inhibit inflammation and increase tight junction protein expressions which may improve BBB function and attenuate CLP-induced brain injury. Hence, the potential beneficial effects of metformin in sepsis, should be considered in future.

Nervous system involvement after infection with COVID-19 and other coronaviruses

Viral infections have detrimental impacts on neurological functions, and even to cause severe neurological damage. Very recently, coronaviruses (CoV), especially severe acute respiratory syndrome CoV 2 (SARS-CoV-2), exhibit neurotropic properties and may also cause neurological diseases. It is reported that CoV can be found in the brain or cerebrospinal fluid. The pathobiology of these neuroinvasive viruses is still incompletely known, and it is therefore important to explore the impact of CoV infections on the nervous system. Here, we review the research into neurological complications in CoV infections and the possible mechanisms of damage to the nervous system.

Specific EEG Encephalopathy Pattern in SARS-CoV-2 Patients

We used quantified electroencephalography (qEEG) to define the features of encephalopathy in patients released from the intensive care unit after severe illness from COVID-19. Artifact-free 120-300 s epoch lengths were visually identified and divided into 1 s windows with 10% overlap. Differential channels were grouped by frontal, parieto-occipital, and temporal lobes. For every channel and window, the power spectrum was calculated and used to compute the area for delta (0-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) bands. Furthermore, Shannon's spectral entropy (SSE) and synchronization by Pearson's correlation coefficient () were computed; cases of patients diagnosed with either infectious toxic encephalopathy (ENC) or post-cardiorespiratory arrest (CRA) encephalopathy were used for comparison. Visual inspection of EEGs of COVID patients showed a near-physiological pattern with scarce anomalies. The distribution of EEG bands was different for the three groups, with COVID midway between distributions of ENC and CRA; specifically, temporal lobes showed different distribution for EEG bands in COVID patients. Besides, SSE was higher and hemispheric connectivity lower for COVID. We objectively identified some numerical EEG features in severely ill COVID patients that can allow positive diagnosis of this encephalopathy.

Sepsis therapies: learning from 30 years of failure of translational research to propose new leads

Sepsis has been identified by the World Health Organization (WHO) as a global health priority. There has been a tremendous effort to decipher underlying mechanisms responsible for organ failure and death, and to develop new treatments. Despite saving thousands of animals over the last three decades in multiple preclinical studies, no new effective drug has emerged that has clearly improved patient outcomes. In the present review, we analyze the reasons for this failure, focusing on the inclusion of inappropriate patients and the use of irrelevant animal models. We advocate against repeating the same mistakes and propose changes to the research paradigm. We discuss the long-term consequences of surviving sepsis and, finally, list some putative approaches-both old and new-that could help save lives and improve survivorship.

Subcutaneous administration of β-hydroxybutyrate improves learning and memory of sepsis surviving mice

Post-sepsis cognitive impairment is one of the major sequelae in sepsis survivors. Its prevention remains clinically challenging. Here we tested the effects and underlying mechanisms of exogenous β-hydroxybutyrate (BHB) on post-sepsis cognitive impairment. We found that subcutaneous administration of BHB increased survival and body weight recovery of sepsis mice and improved learning and memory of sepsis surviving mice in a cecal ligation and perforation-induced sepsis model. Additionally, the improvement of learning and memory of sepsis surviving mice was still detected even if BHB was administrated at the late stage of sepsis. In contrast, glucose solution did not show similar effects. Mechanistically, subcutaneous administration of BHB increased the BHB level of hippocampus, and limited neuroinflammation and neuroplasticity damage in sepsis mice. Intracerebroventricular administration of BHB also alleviated neuroinflammation and cognitive impairment of sepsis surviving mice. In the coculture of neurons, astrocytes, and BV2 cells (a microglial cell line), knocking down the expression of microglial HCA2 (BHB receptor) via a specific shRNA reduced the protection of BHB to lipopolysaccharide-induced inflammatory response and neuron damage more significantly than knocking down neuronal MCT2 (BHB transporter). These data showed that (1) BHB was a potential pharmacological adjunct treatment for prevention of post-sepsis cognitive impairment and (2) inhibiting neuroinflammation via HCA2 was an important mechanism.

Infections as a Risk Factor for and Prognostic Factor After Substance-Induced Psychoses

OBJECTIVE

Previous studies have suggested that infections increase the risk of schizophrenia. In this study, the authors aimed to investigate 1) whether infections increase the risk of substance-induced psychosis, and 2) whether infections increase the risk of converting from substance-induced psychosis to schizophrenia.

METHODS

The study data were drawn from the combined nationwide Danish registers and included all people born in Denmark since 1981. The authors used Cox proportional hazards regression with infections as time-varying covariates, estimating hazard ratios and 95% confidence intervals. Infections were operationalized both as any infection and by the site of infection.

RESULTS

The study included 2,256,779 individuals, for whom 3,618 cases of incident substance-induced psychosis were recorded. Any infection increased the risk of substance-induced psychosis (hazard ratio=1.30, 95% CI=1.22-1.39). For the first 2 years, the risk was doubled. Hepatitis was the infection most strongly associated with substance-induced psychosis (hazard ratio=3.42, 95% CI=2.47-4.74). Different types of infections were linked with different types of substance-induced psychosis. Most associations remained significant after controlling for potential confounders, such as substance use disorders. Only hepatitis predicted conversion to schizophrenia after substance-induced psychosis (hazard ratio=1.87, 95% CI=1.07- 3.26).

CONCLUSIONS

The study results support the hypothesis of an immunological component to psychosis.

Exploring the Biomarkers of Sepsis-Associated Encephalopathy (SAE): Metabolomics Evidence from Gas Chromatography-Mass Spectrometry

Background

Sepsis-associated encephalopathy (SAE) is a transient and reversible brain dysfunction, that occurs when the source of sepsis is located outside of the central nervous system; SAE affects nearly 30% of septic patients at admission and is a risk factor for mortality. In our study, we sought to determine whether metabolite changes in plasma could be a potential biomarker for the early diagnosis and/or the prediction of the prognosis of sepsis.

Method

A total of 31 SAE patients and 28 healthy controls matched by age, gender, and body mass index (BMI) participated in our study. SAE patients were divided into four groups according to the Glasgow Coma Score (GCS). Plasma samples were collected and used to detect metabolism changes by gas chromatography-mass spectrometry (GC-MS). Analysis of variance was used to determine which metabolites significantly differed between the control and SAE groups.

Results

We identified a total of 63 metabolites that showed significant differences among the SAE and control groups. In particular, the 4 common metabolites in the four groups were 4-hydroxyphenylacetic acid; carbostyril, 3-ethyl-4,7-dimethoxy (35.8%); malic acid peak 1; and oxalic acid. The concentration of 4-hydroxyphenylacetic acid in sepsis patients decreased with a decrease of the GCS.

Conclusions

According to recent research on SAE, metabolic disturbances in tissue and cells may be the main pathophysiology of this condition. In our study, we found a correlation between the concentration of 4-hydroxyphenylacetic acid and the severity of consciousness disorders. We suggest that 4-hydroxyphenylacetic acid may be a potential biomarker for SAE and useful in predicting patient prognosis.

Post-treatment With Qing-Ying-Tang, a Compound Chinese Medicine Relives Lipopolysaccharide-Induced Cerebral Microcirculation Disturbance in Mice

Objective: Lipopolysaccharide (LPS) causes microvascular dysfunction, which is a key episode in the pathogenesis of endotoxemia. This work aimed to investigate the effect of Qing-Ying-Tang (QYT), a compound Chinese medicine in cerebral microcirculation disturbance and brain damage induced by LPS.

Methods: Male C57/BL6 mice were continuously transfused with LPS (7.5 mg/kg/h) through the left femoral vein for 2 h. QYT (14.3 g/kg) was given orally 2 h after LPS administration. The dynamics of cerebral microcirculation were evaluated by intravital microscopy. Brain tissue edema was assessed by brain water content and Evans Blue leakage. Cytokines in plasma and brain were evaluated by flow cytometry. Confocal microscopy and Western blot were applied to detect the expression of junction and adhesion proteins, and signaling proteins concerned in mouse brain tissue.

Results: Post-treatment with QYT significantly ameliorated LPS-induced leukocyte adhesion to microvascular wall and albumin leakage from cerebral venules and brain tissue edema, attenuated the increase of MCP-1, MIP-1α, IL-1α, IL-6, and VCAM-1 in brain tissue and the activation of NF-κB and expression of MMP-9 in brain. QYT ameliorated the downregulation of claudin-5, occludin, JAM-1, ZO-1, collagen IV as well as the expression and phosphorylation of VE-cadherin in mouse brain.

Conclusions: This study demonstrated that QYT protected cerebral microvascular barrier from disruption after LPS by acting on the transcellular pathway mediated by caveolae and paracellular pathway mediated by junction proteins. This result suggests QYT as a potential strategy to deal with endotoxemia.

CNS Infections in Immunoincompetent Patients : Neuroradiological and Clinical Features

In patients with immunodeficiency the pathogen spectrum of central nervous system (CNS) infections is broader and different from that of immunocompetent patients. Numerous opportunistic infections are characterized by a high prevalence of viral, bacterial and parasitic pathogens, and depend on the type of impaired immune defense, for example impaired T‑cell or monocyte function, monoclonal antibody treatment, and impaired granulocyte function. Neuroradiological features as well as laboratory findings are often different and versatile in comparison to immunocompetent individuals and pathognomonic imaging findings do not exist; however, knowledge of possible pathways of pathogens in the CNS and preferred tissue affection may help in narrowing down differential diagnoses. Therefore, knowledge of the type of patient and the performed immunomodulatory therapy is essential for the neuroradiological assessment and the differential diagnostic considerations. Moreover, parenchymal reactions in the sense of an immune reconstitution inflammatory syndrome (IRIS) can occur when immunocompetence is restored. This review focus on the most common pathologies in immunocompromised patients, and an overview of imaging features but also of pathology and clinical aspects is given. The synopsis of anamnestic information, clinical findings and structured analysis of the lesion pattern, its spread and short-term follow-up may increase the correct diagnostic classification; however, the gold standard is still determination of the pathogen in the cerebrospinal fluid (CSF), blood cultures or biopsies.

Effects of MFHAS1 on cognitive impairment and dendritic pathology in the hippocampus of septic rats

AIMS

To investigate the effects of malignant fibrous histiocytoma amplified sequence 1 (MFHAS1) on cognitive dysfunction, the expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and amyloid β peptide (Aβ) in the hippocampus, as well as dendritic pathology in the hippocampal CA1 region in sepsis-associated encephalopathy (SAE) rats.

MAIN METHODS

The rats were randomly divided into four groups: 1) control group (subjected to sham surgery), 2) control plus Mfhas1 siRNA group (rats received intracerebroventricular injection of Mfhas1 siRNA after sham surgery), 3) CLP plus control siRNA group (rats received intracerebroventricular injection of control siRNA after cecal ligation and puncture (CLP)), 4) CLP plus Mfhas1 siRNA group (rats received intracerebroventricular injection of Mfhas1 siRNA after CLP). The learning and memory capabilities of the rats were examined by means of fear conditioning and Barnes maze test. The concentration of TNF-α and IL-1β was determined by enzyme-linked immunosorbent assay. The efficiency of siRNA transfection, MFHAS1 and Aβ expression were detected by Western blotting. Total branch lengths of pyramidal dendrites of the CA1 basilar trees and spine density were determined by Golgi staining.

KEY FINDINGS

We observed that MFHAS1 knock-down by Mfhas1 siRNA intracerebroventricular injection could improve cognitive impairment, reduce the expression of TNF-α, IL-1β and Aβ in the hippocampus induced by CLP, and alleviate the dendritic spinal loss of the pyramidal neurons, as well as increase the dendritic branching of the CA1 basilar trees of septic rats.

SIGNIFICANCE

MFHAS1 knock-down can alleviate cognitive impairment, neuroinflammation and dendritic spinal loss in SAE rats.

Association between Elevated Serum Tau Protein Level and Sepsis-Associated Encephalopathy in Patients with Severe Sepsis

Sepsis-associated encephalopathy (SAE) is a common complication of sepsis. It is imperative to recognize, diagnose, and effectively manage SAE at the early stages. The aim of this study was to evaluate the potential of using the serum tau protein level in the diagnosis of SAE and the prediction of SAE outcomes. This was a retrospective and observational study. The patients included in this study were diagnosed with severe sepsis or septic shock. The serum tau protein level was measured using a commercial enzyme-linked immunosorbent assay. The association between the level of serum tau protein and SAE was assessed by multiple logistic regression analysis. One hundred nine patients with severe sepsis were enrolled during a period of two years. Of the 109 enrolled patients, 27 developed SAE. The serum tau protein level was significantly higher in the patients with SAE than that of the non-SAE group. The serum tau protein level and the sequential organ failure assessment (SOFA) score were independent factors that were associated with SAE. The combined use of the serum tau protein level with the SOFA score improved the accuracy in distinguishing SAE from non-SAE patients. A cutoff value serum tau protein level of 75.92 pg/mL had 81.1% sensitivity and 86.1% specificity in predicting the 28-day mortality in patients with severe sepsis. We identified a close association between the serum tau protein level with the appearance of SAE in patients with severe sepsis. The serum tau protein level can be useful in the prediction of poor outcomes in patients with sepsis.

[Features of new-onset organ dysfunction in children with sepsis]

OBJECTIVE

To study the features of new-onset organ dysfunction in children with sepsis in the pediatric intensive care unit (PICU).

METHODS

A retrospective analysis was performed for the clinical data of children with sepsis who were admitted to the PICU from 2015 to 2016. There were 34 children with severe sepsis and 69 with non-severe sepsis, and the two groups were compared in terms of the incidence rate of new-onset organ dysfunction and the functional status on admission and at discharge.

RESULTS

The severe sepsis group had a significantly higher incidence rate of new-onset organ dysfunction than the non-severe sepsis group (38% vs 6%; P<0.05). The children in the non-severe sepsis group had a relatively good functional status on admission, with marked improvement in the overall functional status at discharge. The children in the severe sepsis group had a poor functional status on admission, with mild/moderate abnormalities in consciousness, sensation, communication and respiratory function at discharge.

CONCLUSIONS

Children with non-severe sepsis have a low incidence rate of new-onset organ dysfunction and a good prognosis, and those with severe sepsis often have a high incidence rate of new-onset organ dysfunction and a poor prognosis.

Targeting the Blood-Brain Barrier to Prevent Sepsis-Associated Cognitive Impairment

Sepsis is a systemic inflammatory disease resulting from an infection. This disorder affects 750 000 people annually in the United States and has a 62% rehospitalization rate. Septic symptoms range from typical flu-like symptoms (eg, headache, fever) to a multifactorial syndrome known as sepsis-associated encephalopathy (SAE). Patients with SAE exhibit an acute altered mental status and often have higher mortality and morbidity. In addition, many sepsis survivors are also burdened with long-term cognitive impairment. The mechanisms through which sepsis initiates SAE and promotes long-term cognitive impairment in septic survivors are poorly understood. Due to its unique role as an interface between the brain and the periphery, numerous studies support a regulatory role for the blood-brain barrier (BBB) in the progression of acute and chronic brain dysfunction. In this review, we discuss the current body of literature which supports the BBB as a nexus which integrates signals from the brain and the periphery in sepsis. We highlight key insights on the mechanisms that contribute to the BBB's role in sepsis which include neuroinflammation, increased barrier permeability, immune cell infiltration, mitochondrial dysfunction, and a potential barrier role for tissue non-specific alkaline phosphatase (TNAP). Finally, we address current drug treatments (eg, antimicrobials and intravenous immunoglobulins) for sepsis and their potential outcomes on brain function. A comprehensive understanding of these mechanisms may enable clinicians to target specific aspects of BBB function as a therapeutic tool to limit long-term cognitive impairment in sepsis survivors.

MicroRNA-219 alleviates glutamate-induced neurotoxicity in cultured hippocampal neurons by targeting calmodulin-dependent protein kinase II gamma

Septic encephalopathy is a frequent complication of sepsis, but there are few studies examining the role of microRNAs (miRs) in its pathogenesis. In this study, a miR-219 mimic was transfected into rat hippocampal neurons to model miR-219 overexpression. A protective effect of miR-219 was observed for glutamate-induced neurotoxicity of rat hippocampal neurons, and an underlying mechanism involving calmodulin-dependent protein kinase II γ (CaMKIIγ) was demonstrated. miR-219 and CaMKIIγ mRNA expression induced by glutamate in hippocampal neurons was determined by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). After neurons were transfected with miR-219 mimic, effects on cell viability and apoptosis were measured by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. In addition, a luciferase reporter gene system was used to confirm CaMKIIγ as a target gene of miR-219. Western blot assay and rescue experiments were also utilized to detect CaMKIIγ expression and further verify that miR-219 in hippocampal neurons exerted its effect through regulation of CaMKIIγ. MTT assay and qRT-PCR results revealed obvious decreases in cell viability and miR-219 expression after glutamate stimulation, while CaMKIIγ mRNA expression was increased. MTT, flow cytometry, and caspase-3 activity assays showed that miR-219 overexpression could elevate glutamate-induced cell viability, and reduce cell apoptosis and caspase-3 activity. Moreover, luciferase CaMKIIγ-reporter activity was remarkably decreased by co-transfection with miR-219 mimic, and the results of a rescue experiment showed that CaMKIIγ overexpression could reverse the biological effects of miR-219. Collectively, these findings verify that miR-219 expression was decreased in glutamate-induced neurons, CaMKIIγ was a target gene of miR-219, and miR-219 alleviated glutamate-induced neuronal excitotoxicity by negatively controlling CaMKIIγ expression.

A New Venue of TNF Targeting

The first Food and Drug Administration-(FDA)-approved drugs were small, chemically-manufactured and highly active molecules with possible off-target effects, followed by protein-based medicines such as antibodies. Conventional antibodies bind a specific protein and are becoming increasingly important in the therapeutic landscape. A very prominent class of biologicals are the anti-tumor necrosis factor (TNF) drugs that are applied in several inflammatory diseases that are characterized by dysregulated TNF levels. Marketing of TNF inhibitors revolutionized the treatment of diseases such as Crohn’s disease. However, these inhibitors also have undesired effects, some of them directly associated with the inherent nature of this drug class, whereas others are linked with their mechanism of action, being pan-TNF inhibition. The effects of TNF can diverge at the level of TNF format or receptor, and we discuss the consequences of this in sepsis, autoimmunity and neurodegeneration. Recently, researchers tried to design drugs with reduced side effects. These include molecules with more specificity targeting one specific TNF format or receptor, or that neutralize TNF in specific cells. Alternatively, TNF-directed biologicals without the typical antibody structure are manufactured. Here, we review the complications related to the use of conventional TNF inhibitors, together with the anti-TNF alternatives and the benefits of selective approaches in different diseases.

Function of aquaporins in sepsis: a systematic review

BACKGROUND

Sepsis is a common cause of death in intensive care units worldwide. Due to the high complexity of this immunological syndrome development of novel therapeutic strategies is urgent. Promising drug targets or biomarkers may depict aquaporins (AQPs) as they regulate crucial key mechanisms of sepsis.

MAIN BODY

Here we report on base of the current literature that several AQPs are involved in different physiological processes of sepsis. In immune system mainly AQPs 3, 5 and 9 seem to be important, as they regulate the migration of different immune cells. Several studies showed that AQP3 is essential for T cell function and macrophage migration and that AQP5 and AQP9 regulate neutrophil cell migration and impact sepsis survival. Additionally, to the function in immune system AQPs 1 and 5 play a role in sepsis induced lung injury and their downregulation after inflammatory stimuli impair lung injury. By contrast, AQP4 expression is up-regulated during brain inflammation and aggravates brain edema in sepsis. In kidney AQP2 expression is downregulated during sepsis and can cause renal failure. Some studies also suggest a role of AQP1 in cardiac function.

CONCLUSION

In conclusion, AQPs are involved in many physiological dysfunctions in sepsis and their expressions are differently regulated. Additional research on the regulatory mechanisms of aquaporins may identify potential therapeutic targets.

Translational evidence for two distinct patterns of neuroaxonal injury in sepsis: a longitudinal, prospective translational study

Background

Brain homeostasis deteriorates in sepsis, giving rise to a mostly reversible sepsis-associated encephalopathy (SAE). Some survivors experience chronic cognitive dysfunction thought to be caused by permanent brain injury. In this study, we investigated neuroaxonal pathology in sepsis.

Methods

We conducted a longitudinal, prospective translational study involving (1) experimental sepsis in an animal model; (2) postmortem studies of brain from patients with sepsis; and (3) a prospective, longitudinal human sepsis cohort study at university laboratory and intensive care units (ICUs). Thirteen ICU patients with septic shock, five ICU patients who died as a result of sepsis, fourteen fluid-resuscitated Wistar rats with fecal peritonitis, eleven sham-operated rats, and three human and four rat control subjects were included. Immunohistologic and protein biomarker analysis were performed on rat brain tissue at baseline and 24, 48, and 72 h after sepsis induction and in sham-treated rats. Immunohistochemistry was performed on human brain tissue from sepsis nonsurvivors and in control patients without sepsis. The clinical diagnostics of SAE comprised longitudinal clinical data collection and magnetic resonance imaging (MRI) and electroencephalographic assessments. Statistical analyses were performed using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA). Because of non-Gaussian distribution, the nonparametric Wilcoxon test general linear models and the Spearman correlation coefficient were used.

Results

In postmortem rat and human brain samples, neurofilament phosphoform, β-amyloid precursor protein, β-tubulin, and H&E stains distinguished scattered ischemic lesions from diffuse neuroaxonal injury in septic animals, which were absent in controls. These two patterns of neuroaxonal damage were consistently found in septic but not control human postmortem brains. In experimental sepsis, the time from sepsis onset correlated with tissue neurofilament levels (R = 0.53, p = 0.045) but not glial fibrillary acidic protein. Of 13 patients with sepsis who had clinical features of SAE, MRI detected diffuse axonal injury in 9 and ischemia in 3 patients.

Conclusions

Ischemic and diffuse neuroaxonal injury to the brain in experimental sepsis, human postmortem brains, and in vivo MRI suggest these two distinct lesion types to be relevant. Future studies should be focused on body fluid biomarkers to detect and monitor brain injury in sepsis. The relationship of neurofilament levels with time from sepsis onset may be of prognostic value.

Trial registration

ClinicalTrials.gov, NCT02442986. Registered on May 13, 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1850-7) contains supplementary material, which is available to authorized users.

Sepsis and Septic Shock Strategies

Three therapeutic principles most substantially improve organ dysfunction and survival in sepsis: early, appropriate antimicrobial therapy; restoration of adequate cellular perfusion; timely source control. The new definitions of sepsis and septic shock reflect the inadequate sensitivity, specify, and lack of prognostication of systemic inflammatory response syndrome criteria. Sequential (sepsis-related) organ failure assessment more effectively prognosticates in sepsis and critical illness. Inadequate cellular perfusion accelerates injury and reestablishing perfusion limits injury. Multiple organ systems are affected by sepsis and septic shock and an evidence-based multipronged approach to systems-based therapy in critical illness results in improve outcomes.

qSOFA score: Predictive validity in Enterobacteriaceae bloodstream infections

PURPOSE

To determine whether the quick Sequential Organ Failure Assessment (qSOFA) retains predictive validity in patients with Enterobacteriaceae sepsis that all received appropriate initial antimicrobial therapy.

MATERIALS AND METHODS

Retrospective cohort at Barnes-Jewish Hospital including individuals with Enterobacteriaceae sepsis receiving appropriate initial antimicrobial therapy between 6/2009-12/2013. Outcomes were compared according to qSOFA score and sepsis classification.

RESULTS

We identified 510 patients with Enterobacteriaceae sepsis; 67 (13.1%) died. Mortality was higher in patients with qSOFA scores of 2 or 3 than those with scores of 0 or 1 (13.3% and 42.4% versus 5.1% and 1.8%). In multivariate logistic regression analysis, altered mental status (AMS) alone or qSOFA score≥2 were both predictors of mortality with odds ratios of 8.01 and 5.39, respectively. Regardless of sepsis severity, non-survivors were significantly more likely to have AMS than survivors. Sepsis severity, qSOFA, and AMS had comparable predictive validity for mortality.

CONCLUSIONS

Our results support qSOFA score, AMS, and sepsis severity as acceptable bedside tools for prognostication during initial clinical assessment in patients with sepsis. qSOFA retained its predictive validity in this cohort, suggesting that appropriate initial antimicrobial therapy is not an effect modifier for mortality when using qSOFA for prognostication.