Impact of Hypothermia Initiation and Duration on Perihemorrhagic Edema Evolution After Intracerebral Hemorrhage

Temperature Control in Acute Brain Injury: An Update

Temperature control in severe acute brain injury (SABI) is a key component of acute management. This manuscript delves into the complex role of temperature management in SABI, encompassing conditions like traumatic brain injury (TBI), acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), aneurysmal subarachnoid hemorrhage (aSAH), and hypoxemic/ischemic brain injury following cardiac arrest. Fever is a common complication in SABI and is linked to worse neurological outcomes due to increased inflammatory responses and intracranial pressure (ICP). Temperature management, particularly hypothermic temperature control (HTC), appears to mitigate these adverse effects primarily by reducing cerebral metabolic demand and dampening inflammatory pathways. However, the effectiveness of HTC varies across different SABI conditions. In the context of post-cardiac arrest, the impact of HTC on neurological outcomes has shown inconsistent results. In cases of TBI, HTC seems promising for reducing ICP, but its influence on long-term outcomes remains uncertain. For AIS, clinical trials have yet to conclusively demonstrate the benefits of HTC, despite encouraging preclinical evidence. This variability in efficacy is also observed in ICH, aSAH, bacterial meningitis, and status epilepticus. In pediatric and neonatal populations, while HTC shows significant benefits in hypoxic-ischemic encephalopathy, its effectiveness in other brain injuries is mixed. Although the theoretical basis for employing temperature control, especially HTC, is strong, the clinical outcomes differ among various SABI subtypes. The current consensus indicates that fever prevention is beneficial across the board, but the application and effectiveness of HTC are more nuanced, underscoring the need for further research to establish optimal temperature management strategies. Here we provide an overview of the clinical evidence surrounding the use of temperature control in various types of SABI.

Emergent Management of Intracerebral Hemorrhage

OBJECTIVE

Nontraumatic intracerebral hemorrhage (ICH) is a potentially devastating cerebrovascular disorder. Several randomized trials have assessed interventions to improve ICH outcomes. This article summarizes some of the recent developments in the emergent medical and surgical management of acute ICH.

LATEST DEVELOPMENTS

Recent data have underscored the protracted course of recovery after ICH, particularly in patients with severe disability, cautioning against early nihilism and withholding of life-sustaining treatments. The treatment of ICH has undergone rapid evolution with the implementation of intensive blood pressure control, novel reversal strategies for coagulopathy, innovations in systems of care such as mobile stroke units for hyperacute ICH care, and the emergence of newer minimally invasive surgical approaches such as the endoport and endoscope-assisted evacuation techniques.

ESSENTIAL POINTS

This review discusses the current state of evidence in ICH and its implications for practice, using case illustrations to highlight some of the nuances involved in the management of acute ICH.

Mild hypothermia promotes neuronal differentiation of human neural stem cells via RBM3-SOX11 signaling pathway

Both therapeutic hypothermia and neural stem cells (NSCs) transplantation have shown promise in neuroprotection and neural repair after brain injury. However, the effects of therapeutic hypothermia on neuronal differentiation of NSCs are not elucidated. In this study, we aimed to investigate whether mild hypothermia promoted neuronal differentiation in cultured and transplanted human NSCs (hNSCs). A significant increase in neuronal differentiation rate of hNSCs was found when exposed to 35°C, from 33% to 45% in vitro and from 7% to 15% in vivo. Additionally, single-cell RNA sequencing identified upregulation of RNA-binding motif protein 3 (RBM3) in neuroblast at 35°C, which stabilized the SRY-box transcription factor 11 (SOX11) mRNA and increased its protein expression, leading to an increase in neuronal differentiation of hNSCs. In conclusion, our study highlights that mild hypothermia at 35°C enhances hNSCs-induced neurogenesis through the novel RBM3-SOX11 signaling pathway, and provides a potential treatment strategy in brain disorders.

Hypothermia and temperature modulation for intracerebral hemorrhage (ICH): pathophysiology and translational applications

Background

Intracerebral hemorrhage (ICH) still poses a substantial challenge in clinical medicine because of the high morbidity and mortality rate that characterizes it. This review article expands into the complex pathophysiological processes underlying primary and secondary neuronal death following ICH. It explores the potential of therapeutic hypothermia as an intervention to mitigate these devastating effects.

Methods

A comprehensive literature review to gather relevant studies published between 2000 and 2023.

Discussion

Primary brain injury results from mechanical damage caused by the hematoma, leading to increased intracranial pressure and subsequent structural disruption. Secondary brain injury encompasses a cascade of events, including inflammation, oxidative stress, blood-brain barrier breakdown, cytotoxicity, and neuronal death. Initial surgical trials failed to demonstrate significant benefits, prompting a shift toward molecular mechanisms driving secondary brain injury as potential therapeutic targets. With promising preclinical outcomes, hypothermia has garnered attention, but clinical trials have yet to establish its definitive effectiveness. Localized hypothermia strategies are gaining interest due to their potential to minimize systemic complications and improve outcomes. Ongoing and forthcoming clinical trials seek to clarify the role of hypothermia in ICH management.

Conclusion

Therapeutic hypothermia offers a potential avenue for intervention by targeting the secondary injury mechanisms. The ongoing pursuit of optimized cooling protocols, localized cooling strategies, and rigorous clinical trials is crucial to unlocking the potential of hypothermia as a therapeutic tool for managing ICH and improving patient outcomes.

Nursing Management of Temperature in a Patient with Stroke

Fever is common in patients with stroke and is associated with worse outcomes. Studies in brain injury informed interventions commonly termed therapeutic temperature management (TTM) to improve the monitoring and management of fever. While the role and benefit of TTM in stroke patients has not been well studied, the nurse and healthcare team must extrapolate existing data to determine how to best monitor and apply TTM after stroke. Nurses should be knowledgeable about interventions to monitor and manage complications of TTM (eg, shivering), the studies underway to quantify the impact of fever treatment and emerging technology expected to improve TTM.

Consensus recommendations on therapeutic hypothermia after minimally invasive intracerebral hemorrhage evacuation from the hypothermia for intracerebral hemorrhage (HICH) working group

Background and purpose

Therapeutic hypothermia (TH), or targeted temperature management (TTM), is a classic treatment option for reducing inflammation and potentially other destructive processes across a wide range of pathologies, and has been successfully used in numerous disease states. The ability for TH to improve neurological outcomes seems promising for inflammatory injuries but has yet to demonstrate clinical benefit in the intracerebral hemorrhage (ICH) patient population. Minimally invasive ICH evacuation also presents a promising option for ICH treatment with strong preclinical data but has yet to demonstrate functional improvement in large randomized trials. The biochemical mechanisms of action of ICH evacuation and TH appear to be synergistic, and thus combining hematoma evacuation with cooling therapy could provide synergistic benefits. The purpose of this working group was to develop consensus recommendations on optimal clinical trial design and outcomes for the use of therapeutic hypothermia in ICH in conjunction with minimally invasive ICH evacuation.

Methods

An international panel of experts on the intersection of critical-care TH and ICH was convened to analyze available evidence and form a consensus on critical elements of a focal cooling protocol and clinical trial design. Three focused sessions and three full-group meetings were held virtually from December 2020 to February 2021. Each meeting focused on a specific subtopic, allowing for guided, open discussion.

Results

These recommendations detail key elements of a clinical cooling protocol and an outline for the roll-out of clinical trials to test and validate the use of TH in conjunction with hematoma evacuation as well as late-stage protocols to improve the cooling approach. The combined use of systemic normothermia and localized moderate (33.5°C) hypothermia was identified as the most promising treatment strategy.

Conclusions

These recommendations provide a general outline for the use of TH after minimally invasive ICH evacuation. More research is needed to further refine the use and combination of these promising treatment paradigms for this patient population.

Perihematomal Edema After Intracerebral Hemorrhage: An Update on Pathogenesis, Risk Factors, and Therapeutic Advances

Intracerebral hemorrhage (ICH) has one of the worst prognoses among patients with stroke. Surgical measures have been adopted to relieve the mass effect of the hematoma, and developing targeted therapy against secondary brain injury (SBI) after ICH is equally essential. Numerous preclinical and clinical studies have demonstrated that perihematomal edema (PHE) is a quantifiable marker of SBI after ICH and is associated with a poor prognosis. Thus, PHE has been considered a promising therapeutic target for ICH. However, the findings derived from existing studies on PHE are disparate and unclear. Therefore, it is necessary to classify, compare, and summarize the existing studies on PHE. In this review, we describe the growth characteristics and relevant underlying mechanism of PHE, analyze the contributions of different risk factors to PHE, present the potential impact of PHE on patient outcomes, and discuss the currently available therapeutic strategies.

Therapeutic hypothermia for intracerebral hemorrhage: Systematic review and meta-analysis of the experimental and clinical literature

BACKGROUND

Intracerebral hemorrhage remains the deadliest form of stroke worldwide, inducing neuronal death through a wide variety of pathways. Therapeutic hypothermia is a robust and well-studied neuroprotectant widely used across a variety of specialties.

AIMS

This review summarizes results from preclinical and clinical studies to highlight the overall effectiveness of therapeutic hypothermia to improve long-term intracerebral hemorrhage outcomes while also elucidating optimal protocol regimens to maximize therapeutic effect.

SUMMARY OF REVIEW

A systematic review was conducted across three databases to identify trials investigating the use of therapeutic hypothermia to treat intracerebral hemorrhage. A random-effects meta-analysis was conducted on preclinical studies, looking at neurobehavioral outcomes, blood brain barrier breakdown, cerebral edema, hematoma volume, and tissue loss. Several mixed-methods meta-regression models were also performed to adjust for variance and variations in hypothermia induction procedures. Twwenty-one preclinical studies and five human studies were identified. The meta-analysis of preclinical studies demonstrated a significant benefit in behavioral scores (ES = -0.43, p = 0.02), cerebral edema (ES = 1.32, p = 0.0001), and blood brain barrier (ES = 2.73, p ≤ 0.00001). Therapeutic hypothermia was not found to significantly affect hematoma expansion (ES = -0.24, p = 0.12) or tissue loss (ES = 0.06, p = 0.68). Clinical study outcome reporting was heterogeneous; however, there was recurring evidence of therapeutic hypothermia-induced edema reduction.

CONCLUSIONS

The combined preclinical evidence demonstrates that therapeutic hypothermia reduced multiple cell death mechanisms initiated by intracerebral hemorrhage; yet, there is no definitive evidence in clinical studies. The cooling strategies employed in both preclinical and clinical studies were highly diverse, and focused refinement of cooling protocols should be developed in future preclinical studies. The current data for therapeutic hypothermia in intracerebral hemorrhage remains questionable despite the highly promising indications in preclinical studies. Definitive randomized controlled studies are still required to answer this therapeutic question.

Influence of Early Enteral Nutrition on Clinical Outcomes in Neurocritical Care Patients With Intracerebral Hemorrhage

Objective: Early enteral nutrition (EEN) represents the current standard of care for patients treated in general intensive care units (ICU). Specific nutritional recommendations for patients receiving dedicated neurocritical care are not established. This study investigated associations of EEN with clinical outcomes for patients suffering from intracerebral hemorrhage treated at a neurological ICU (NICU).

Methods: This retrospective cohort study included patients admitted to the NICU with atraumatic ICH over a 4-year period. Nutritional data, demographic, clinical, radiological, and laboratory characteristics were assessed. EEN was defined as any enteral nutrition within 48 hours after admission. Comparisons were undertaken for patients with EEN vs. those without, further propensity score (PS) matching (caliper 0.2; one: many) was used to account for baseline imbalances. Primary outcome was the modified Rankin Scale (0–3 = favorable, 4–6 = unfavorable) at 12 months, secondary outcomes comprised perihemorrhagic edema (PHE) volume, infectious complications during the hospital stay, and mRS at 3 months, as well as mortality rates at 3 and 12 months.

Results: Of 166 ICH-patients treated at the NICU, 51 (30.7%) patients received EEN, and 115 (69.3%) patients received no EEN (nEEN). After propensity score matching, calories delivered from enteral nutrition (EEN 161.4 [106.4–192.3] kcal/day vs. nEEN 0.0 [0.0–0.0], P < 0.001) and the total calories (EEN 190.0 [126.0–357.0] kcal/day vs. nEEN 33.6 [0.0–190.0] kcal/day, P < 0.001) were significantly different during the first 48 h admitted in NICU. Functional outcome at 12 months (mRS 4–6, EEN 33/43 [76.7%] vs. nEEN, 49/64 [76. 6%]; P = 1.00) was similar in the two groups. There were neither differences in mRS at 3 months, nor in mortality rates at 3 and 12 months between the two groups. EEN did not affect incidence of infective complications or gastrointestinal adverse events during the hospital stay; however, EEN was associated with significantly less extent of PHE evolution [maximum absolute PHE (OR 0.822, 95% CI 0.706–0.957, P = 0.012); maximum relative PHE (OR 0.784, 95% CI 0.646–0.952, P = 0.014)].

Conclusion: In our study, EEN was associated with reduced PHE in ICH-patients treated at a NICU. However, this observation did not translate into improved survival or functional outcome at 3 and 12 months.

Prognostic significance of early pyrexia in acute intracerebral haemorrhage: The INTERACT2 study

INTRODUCTION

Uncertainty exists over the prognostic significance of pyrexia in acute intracerebral haemorrhage (ICH). We aimed to determine the association of elevated body temperature with clinical and imaging outcomes among participants of the main Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2).

METHODS

Post-hoc analyses of INTERACT2, an international open, blinded outcome assessed, randomised trial of 2839 patients with spontaneous ICH (<6 h of onset) and elevated systolic blood pressure (SBP, 150-220 mmHg) randomly assigned to intensive (SBP target <140 mmHg) or guideline-recommended (SBP target < 180 mmHg) BP management. Multivariable logistic regression was used to determine associations of elevated baseline body temperature (<37.5 vs. ≥37.5 °C) and 90-day clinical outcome defined on the modified Rankin scale (mRS). Analysis of covariance determined relations of body temperature and haematoma and perihaematomal oedema (PHE) volumes, at baseline and 24 h post-randomisation.

RESULTS

Of 2792 participants with data available at admission, 39 (1.4%) patients had elevated body temperature ≥ 37.5 °C. Elevated body temperature was significantly associated with 90-day mortality (adjusted odds ratio 2.44; 95% confidence interval 1.02-5.82; P = .044) but not with major disability alone (mRS scores 3-5) and combination death or major disability (mRS scores 3-6). Elevated body temperature was also associated with larger PHE volume at baseline (10.89 vs. 3.14 cm³, P < .001;) and 24 h (12.43 vs 5.76 cm³, P = .018) but not with haematoma volumes at these time points.

CONCLUSION

Early pyrexia in mild to moderate ICH is associated with greater mortality and larger PHE volume, suggesting an early inflammatory-mediated reaction.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov (NCT00716079).

Antihyperthermic treatment decreases perihematomal hypodensity

OBJECTIVE

To investigate the effect on perihematomal hypodensity and outcome of a decrease in body temperature in the first 24 hours in patients with intracerebral hemorrhage (ICH).

METHODS

In this retrospective study on a prospectively registered database, among the 1,100 patients, 795 met all the inclusion criteria. Temperature variations in the first 24 hours and perihematomal hypodensity (PHHD) were recorded. Patients ≥37.5°C were treated with antihyperthermic drugs for at least 48 hours. The main objective was to determine the association among temperature variation, PHHD, and outcome at 3 months.

RESULTS

The decrease in temperature in the first 24 hours increased the possibility of good outcome 11-fold. Temperature decrease, lower PHHD volume, and a good outcome were observed in 31.8% of the patients who received antihyperthermic treatment.

CONCLUSION

The administration of early antihyperthermic treatment in patients with spontaneous ICH with a basal axillary temperature ≥37.5°C resulted in good outcome in a third of the treated patients.

MicroRNA-152 attenuates neuroinflammation in intracerebral hemorrhage by inhibiting thioredoxin interacting protein (TXNIP)-mediated NLRP3 inflammasome activation

Neuroinflammation significantly contributes to brain injury and neurological deterioration following intracerebral hemorrhage (ICH). MicroRNA-152(miR-152) was reported to be downregulated in ICH patients and to possess anti-inflammatory properties in other diseases. In this study, we aimed to explore the role of miR-152 in ICH, and the underlying mechanisms, using a collagenase-induced rat ICH model and hemin-exposure as a cell model. We first confirmed that miR-152 was consistently downregulated in both models. Overexpression of miR-152 in microglial BV2 cells reduced hemin-induced inflammatory response and reactive oxygen species (ROS) generation, thus protecting co-cultured neuronal HT22 cells. Moreover, overexpression of miR-152 by intracerebroventricular lentivirus injection in ICH rats significantly alleviated neurodecifits, brain edema, and hematoma. These changes were associated with a marked reduction in ICH-induced neuronal death, as detected by co-staining of NeuN and TUNEL, and ICH-induced neuroinflammation, as revealed by inflammatory cytokine levels as well as by the number of Iba1 positive-stained cells in the perihematomal region. Mechanistically, miR-152 significantly inhibited ICH-induced TXNIP expression, and its overexpression blocked the interaction between TXNIP and NOD-like receptor pyrin domain containing 3(NLRP3), thus inhibiting NLRP3-driven inflammasome activation to attenuate neuroinflammation in vivo and in vitro. Moreover, the results of si-TXNIP transfection further confirmed that TXNIP inhibition was involved in the reduction of NLRP3 inflammasome activation by the overexpression of miR-152. Collectively, the present study demonstrates that miR-152 confers protection against ICH-induced neuroinflammation and brain injury by inhibiting TXNIP-mediated NLRP3 inflammasome activation, indicating a potential strategy for ICH treatment.

The risk factors and prognosis of delayed perihematomal edema in patients with spontaneous intracerebral hemorrhage

PURPOSE

We hypothesize delayed perihematomal edema (DHE) leads to secondary injury after spontaneous intracerebral hemorrhage (sICH) with a poor prognosis. Hence, we need to investigate the risk factors of DHE and identify whether DHE will predict the poor outcome of sICH.

METHODS

We retrospectively recruited 121 patients with sICH admitted to the Department of Neurology from January 2014 to August 2018. After dividing all these patients into DHE group and non-DHE group, we analyzed the potential risk factors and outcome of DHE using a multivariate logistic regression model.

RESULTS

We conclude DHE after sICH associates with age, hospitalization time, hematoma shape, blood pressure upon admission, alcohol consumption, blood sodium level, and baseline hematoma volume within 24 hours after symptom onset, among which differences were statistically significant (P < .05). Logistic regression analysis finally identified that age (OR = 0.958, 95% CI = 0.923-0.995) and the baseline hematoma volume (OR = 1.161, 95% CI = 1.089-1.238) were the most significant risk factors for DHE, and moreover, the DHE (OR = 3.062, 95% CI = 1.196-7.839) was also a risk factor for poor prognosis in sICH patients.

CONCLUSION

We suggest DHE is a clinical predictor of secondary injury following sICH and poor prognosis. In addition, age and baseline hematoma volume are considered significant high-risk factors for DHE in patients with sICH.

Roles Played by the Na+/Ca2+ Exchanger and Hypothermia in the Prevention of Ischemia-Induced Carrier-Mediated Efflux of Catecholamines into the Extracellular Space: Implications for Stroke Therapy

The release of [³H]dopamine ([³H]DA) and [³H]noradrenaline ([³H]NA) in acutely perfused rat striatal and cortical slice preparations was measured at 37 °C and 17 °C under ischemic conditions. The ischemia was simulated by the removal of oxygen and glucose from the Krebs solution. At 37 °C, resting release rates in response to ischemia were increased; in contrast, at 17 °C, resting release rates were significantly reduced, or resting release was completely prevented. The removal of extracellular Ca²⁺ further increased the release rates of [³H]DA and [³H]NA induced by ischemic conditions. This finding indicated that the Na⁺/Ca²⁺ exchanger (NCX), working in reverse in the absence of extracellular Ca²⁺, fails to trigger the influx of Ca²⁺ in exchange for Na⁺ and fails to counteract ischemia by further increasing the intracellular Na⁺ concentration ([Na⁺]_i). KB-R7943, an inhibitor of NCX, significantly reduced the cytoplasmic resting release rate of catecholamines under ischemic conditions and under conditions where Ca²⁺ was removed. Hypothermia inhibited the excessive release of [³H]DA in response to ischemia, even in the absence of Ca²⁺. These findings further indicate that the NCX plays an important role in maintaining a high [Na⁺]_i, a condition that may lead to the reversal of monoamine transporter functions; this effect consequently leads to the excessive cytoplasmic tonic release of monoamines and the reversal of the NCX. Using HPLC combined with scintillation spectrometry, hypothermia, which enhances the stimulation-evoked release of DA, was found to inhibit the efflux of toxic DA metabolites, such as 3,4-dihydroxyphenylacetaldehyde (DOPAL). In slices prepared from human cortical brain tissue removed during elective neurosurgery, the uptake and release values for [³H]NA did not differ from those measured at 37 °C in slices that were previously maintained under hypoxic conditions at 8 °C for 20 h. This result indicates that hypothermia preserves the functions of the transport and release mechanisms, even under hypoxic conditions. Oxidative stress (H₂O₂), a mediator of ischemic brain injury enhanced the striatal resting release of [³H]DA and its toxic metabolites (DOPAL, quinone). The study supports our earlier findings that during ischemia transmitters are released from the cytoplasm. In addition, the major findings of this study that hypothermia of brain slice preparations prevents the extracellular calcium concentration ([Ca²⁺]_o)-independent non-vesicular transmitter release induced by ischemic insults, inhibiting Na⁺/Cl⁻-dependent membrane transport of monoamines and their toxic metabolites into the extracellular space, where they can exert toxic effects.

Comparison of decision-making in neonatal care between China and Japan

BACKGROUND

Various differences between China and Japan in approaches to medical treatment have been noted, but a few studies have examined differences in medical decision-making, especially in neonatal care. The aim of this study was to clarify these differences by means of a questionnaire.

METHODS

The subjects were physicians on the staff of NICUs in China and Japan. The study questionnaire consisted of three parts dealing with the general characteristics of the participants, questions about treatment strategies for hypothetical, critically ill infants, and general questions about the treatment of foreign patients. The Likert scale was used to assess the treatment strategies and the results were analyzed statistically. Subgroup analysis by age, sex, and medical and NICU experience was also performed.

RESULTS

The proportion of respondents in the Chinese and Japanese groups was 26/26 (100%) and 26/31 (84%), respectively. There was a significant difference between the Chinese and Japanese groups for 8 of 75 questions; Chinese physicians chose the positive treatment or examination options for these eight questions unlike their Japanese counterparts. The responses of the younger, less experienced physicians in both countries were more similar to each other, and more positive than those of their older, more experienced colleagues.

CONCLUSION

Chinese physicians showed a more positive attitude toward examination and treatment, whereas Japanese physicians showed a more cautious attitude.

Perihematomal edema: Implications for intracerebral hemorrhage research and therapeutic advances

In humans, perihematomal edema (PHE) is considered to be a radiological marker of secondary injury following intracerebral hemorrhage (ICH). There is also evidence that PHE might contribute to poor outcome in ICH patients. Given the rising interest in secondary injury after ICH as a therapeutic target, PHE is becoming increasingly used as a proof-of-concept surrogate measure to assess the potential efficacy of various therapeutic interventions in clinical trials. We review the pathophysiology of PHE and its evolution, its prognostic significance and relationship to clinical outcomes, and variabilities in its detection and measurement methodologies to determine the advantages versus shortcomings of using PHE as a translational target or radiological marker to examine the efficacy of interventions aiming to mitigate secondary injury in ICH.

Programmed Cell Death after Intracerebral Hemorrhage

Background:

Intracerebral hemorrhage (ICH) accounts for up to 15% of all strokes and is characterized by high rates of mortality and morbidity. The post-ICH brain injury can be distinguished in 1) primary, which are caused by disrup-tion and mechanical deformation of brain tissue due to hematoma growth and 2) secondary, which are induced by microglia activation, mitochondrial dysfunction, neurotransmitter and inflammatory mediator release. Although these events typically lead to necrosis, the occurrence of programmed cell death has also been reported after ICH.

Methods:

We reviewed recent publications describing advance in pre- and clinic ICH research.

Results:

At present, treatment of ICH patients is based on oral anticoagulant reversal, management of blood pressure and other medical complications. Several pre-clinical studies showed promising results and demonstrated that anti-oxidative and anti-inflammatory treatments reduced neuronal cell death, however, to date, all of these attempts have failed in randomized controlled clinical trials. Yet, the time frame of administration may be crucial in translation from animal to clinical studies. Furthermore, the latest pre-clinical research points toward the existence of other, apoptosis-unrelated forms kinds of pro-grammed cell death.

Conclusion:

Our review summarizes current knowledge of pathways leading to programmed cell death after ICH in addition to data from clinical trials. Some of the pre-clinical results have not yet demonstrated clinical confirmation, however they sig-nificantly contribute to our understanding of post-ICH pathology and can contribute to development of new therapeutic ap-proaches, decreasing mortality and improving ICH patients’ quality of life.

Tim-3 enhances brain inflammation by promoting M1 macrophage polarization following intracerebral hemorrhage in mice

Macrophage polarization contributes to brain inflammation following spontaneous intracerebral hemorrhage (ICH). T cell immunoglobulin and mucin domain-3 (Tim-3) has been identified to induce macrophage mediated inflammation following ICH. However, the regulation of Tim-3 on macrophage polarization following ICH has not been fully studied. In current experiment, we explored Tim-3 expression, macrophage polarization, brain water content and neurological function in WT and Tim-3^-/^- ICH mice. In addition, downstream transcriptional factor TRIF and IRF3 were also analyzed. We found that ICH promoted Tim-3 expression and M1 polarization in the perihematomal region of WT mice, leading to increased brain water content and neurological impairment. However, deletion of Tim-3 expression attenuated M1 polarization, decreased rain water content and improved neurological function of ICH mice. Furthermore, Tim-3 signal promoted transcriptional factors TRIF and IRF3 levels, regulating macrophage polarization. The data suggested that Tim-3 played a crucial role in the macrophage polarization and brain inflammation following ICH, and might represent a promising way in ICH therapy.

Inflammation, edema and poor outcome are associated with hyperthermia in hypertensive intracerebral hemorrhages

Background and purpose

The deleterious effect of hyperthermia on intracerebral hemorrhage (ICH) has been studied. However, the results are not conclusive and new studies are needed to elucidate clinical factors that influence the poor outcome. The aim of this study was to identify the clinical factors (including ICH etiology) that influence the poor outcome associated with hyperthermia and ICH. We also tried to identify potential mechanisms involved in hyperthermia during ICH.

Methods

We conducted a retrospective study enrolling patients with non‐traumatic ICH from a prospective registry. We used logistic regression models to analyze the influence of hyperthermia in relation to different inflammatory and endothelial dysfunction markers, hematoma growth and edema volume in hypertensive and non‐hypertensive patients with ICH.

Results

We included 887 patients with ICH (433 hypertensive, 50 amyloid, 117 by anticoagulants and 287 with other causes). Patients with hypertensive ICH showed the highest body temperature (37.5 ± 0.8°C) as well as the maximum increase in temperature (0.9 ± 0.1°C) within the first 24 h. Patients with ICH of hypertensive etiologic origin, who presented hyperthermia, showed a 5.3‐fold higher risk of a poor outcome at 3 months. We found a positive relationship (r = 0.717, P < 0.0001) between edema volume and hyperthermia during the first 24 h but only in patients with ICH of hypertensive etiologic origin. This relationship seems to be mediated by inflammatory markers.

Conclusion

Our data suggest that hyperthermia, together with inflammation and edema, is associated with poor outcome only in ICH of hypertensive etiology.

Therapeutic time window and regulation of autophagy by mild hypothermia after intracerebral hemorrhage in rats

Although recent studies have shown that mild hypothermia has neuroprotective effects on intracerebral hemorrhage (ICH), the therapeutic time window of the therapy and the role of autophagy as a potential neuroprotective mechanism remain unclear. This study was aimed to investigate the appropriate time window of mild hypothermia and the regulation of autophagy during the treatment in a rat model of autologous blood-injected ICH injury. The rats were divided into Sham, normothermic (NT) and hypothermic (HT) groups. HT groups received mild hypothermia (33 °C-35 °C) for 48 h starting from 3 h (HT3), 6 h (HT6), and 12 h (HT12) respectively after ICH. The neurological function, brain edema, blood brain barrier (BBB) permeability and volume of tissue loss were tested. The expression of metrix metalloproteinase 9 (MMP-9) and tight junction (TJ) protein including Occludin and Claudin-5 around the hematoma were detected by Western blot. Moreover, autophagy after ICH was detected by the ratio of LC3B-II/I, and the expression of Beclin-1 and p62, while apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dURP nick end labelling (TUNEL) staining and expression of Bcl-2, Bim, cleaved Caspase-3. Compared with NT group, neurological deficit, brain edema and BBB permeability were attenuated in HT6 and HT12 groups, but not in HT3 group, while volume of tissue loss was reduced only in HT12 group. The expression of MMP-9 and the degradation of Occludin and Claudin-5 were suppressed only in HT6 and HT12 groups, especially in the latter one. Moreover, neuronal autophagy and apoptosis induced by ICH were downregulated in HT12 group. The results suggested that mild hypothermia initiated at 6 h or 12 h post-injury was neuroprotective in ICH model of rats, especially at 12 h post-injury, via suppression of autophagy upregulated by ICH.

Peak perihemorrhagic edema correlates with functional outcome in intracerebral hemorrhage

OBJECTIVE

To evaluate the association of perihemorrhagic edema (PHE) evolution and peak edema extent with day 90 functional outcome in patients with intracerebral hemorrhage (ICH) and identify pathophysiologic factors influencing edema evolution.

METHODS

This retrospective cohort study included patients with spontaneous supratentorial ICH between January 2006 and January 2014. ICH and PHE volumes were studied using a validated semiautomatic volumetric algorithm. Multivariable logistic regression and propensity score matching (PSM) accounting for age, ICH volume, and location were used for assessing measures associated with functional outcome and PHE evolution. Clinical outcome on day 90 was assessed using the modified Rankin Scale (0-3 = favorable, 4-6 = poor).

RESULTS

A total of 292 patients were included. Median age was 70 years (interquartile range [IQR] 62-78), median ICH volume on admission 17.7 mL (IQR 7.9-40.2). Besides established factors for functional outcome, i.e., ICH volume and location, age, intraventricular hemorrhage, and NIH Stroke Scale score on admission, multivariable logistic regression revealed peak PHE volume (odds ratio [OR] 0.984 [95% confidence interval (CI) 0.973-0.994]) as an independent predictor of day 90 outcome. Peak PHE volume was independently associated with initial PHE increase up to day 3 (OR 1.060 [95% CI 1.018-1.103]) and neutrophil to lymphocyte ratio on day 6 (OR 1.236 [95% CI 1.034-1.477; PSM cohort, n = 124]). Initial PHE increase (PSM cohort, n = 224) was independently related to hematoma expansion (OR 3.647 [95% CI 1.533-8.679]) and fever burden on days 2-3 (OR 1.456 [95% CI 1.103-1.920]).

CONCLUSION

Our findings suggest that peak PHE volume represents an independent predictor of functional outcome after ICH. Inflammatory processes and hematoma expansion seem to be involved in PHE evolution and may represent important treatment targets.

Radiologic Measurement of Brain Swelling in Patients with Large Hemispheric Infarctions During Targeted Temperature Management

Brain herniation is most often the result of severe brain swelling and can rapidly lead to death or brain death. We retrospectively identified radiologic indicators to evaluate the effects of targeted temperature management (TTM) on the extent of cerebral edema and determine the cutoff values that best predict TTM outcomes in patients with large hemispheric infarction. We retrospectively reviewed brain computed tomography (CT) scans of 21 patients with large hemispheric infarctions, who were treated with TTM. We excluded 4 patients whose CT scans were inadequate for evaluation, which left 17 patients. We divided the patients into success and failure groups. TTM failure was defined as death or the need for decompressive hemicraniectomy (DHC) after TTM. Infarction size was measured as the total restricted area in diffusion-weighted imaging that was performed on admission. CT scans were obtained on the first and second days after TTM initiation and then every 2 days. We measured septum pellucidum shifts (SPS) and pineal gland shifts (PGS) on CT scans. The median time from symptom onset to TTM initiation was 14.5 hours. Ten patients were successfully treated with TTM, six patients died, and one patient underwent a DHC. Initial infarction sizes were not significantly different between the success and failure groups (p = 0.529), but the SPS and PGS at 36-72 hours after TTM initiation were (mean SPS: 5.0 vs. 14.9 mm, p = 0.001; mean PGS: 2.3 vs. 7.9 mm, p = 0.001). The sensitivity and negative predictive value for TTM failure caused by cerebral edema (SPS ≥9.25 mm and PGS ≥3.70 mm) at 36-72 hours after TTM initiation were both 100%. The SPS and PGS on CT scans taken 36-72 hours after TTM initiation may help to estimate the effect of TTM on cerebral edema and guide further treatment.

Effect and Feasibility of Therapeutic Hypothermia in Patients with Hemorrhagic Stroke: A Systematic Review and Meta-Analysis

INTRODUCTION

Therapeutic hypothermia (TH) has shown good results in experimental models of hemorrhagic stroke. The clinical application of TH, however, remains controversial, since reports regarding its therapeutic effect are inconsistent.

METHODS

We conducted a systematic review based on Preferred Reporting Items for Systematic Reviews and Meta-analyses comparing TH with a control group in terms of mortality, poor outcome, delayed cerebral ischemia (DCI), and specific complications. The subgroup analyses were stratified by study type, country, mean age, hemorrhage type, cooling method, treatment duration, rewarming velocity, and follow-up time.

RESULTS

Nine studies were included, most of which were of moderate quality. The overall effect demonstrated insignificant differences in mortality (risk ratio [RR] 0.78; 95% confidence interval [CI] 0.58-1.06; P = 0.11) and poor outcome rate (RR 0.89; 95% CI 0.70-1.12; P = 0.32) between TH and the control group. However, sensitivity analyses, after we omitted 1 study, achieved a statistically significant difference in poor outcome favoring TH. Moreover, in the subgroup analyses, the results derived from randomized studies revealed that TH significantly reduced poor outcomes (RR 0.40; 95% CI 0.22-0.74; P = 0.003). In addition, TH significantly reduced DCI compared with control (RR 0.61; 95% CI 0.40-0.93; P = 0.02). The incidence of specific complications (rebleeding, pneumonia, sepsis, arrhythmia, and hydrocephalus) between the 2 groups were comparable and did not reach significant difference.

CONCLUSIONS

The overall effect showed TH did not significantly reduce mortality and poor outcomes but led to a decreased incidence of DCI. Compared with control, TH resulted in comparable incidences of specific complications.

[Current treatment concepts in intracerebral hemorrhage]

BACKGROUND AND OBJECTIVE

In recent years, various important studies investigating the management of intracerebral hemorrhage (ICH) have been published. However, these have not entered guideline recommendations yet. Therefore, essential results are summarized here and the findings are integrated into current treatment concepts.

MATERIALS AND METHODS

Based on a dedicated literature review and the authors' experience, up-to-date and high-quality investigations were identified.

RESULTS AND DISCUSSION

Randomized data and meta-analyses provide evidence that aggressive blood-pressure reduction (targeting a systolic blood pressure <140 mm Hg) appears safe and reduces hematoma enlargement. ICH associated with intake of vitamin K antagonists should be reversed immediately using prothrombin complex concentrates (PCC) and vitamin K, targeting at least international normalized ratio levels below 1.3. For dabigatran-related ICH, an antidote (idarucizumab) is available for reversal, but in ICH under the use of factor Xa inhibitors evidence is poor. However, reversal should be carried out using high-dosed PCC (50 IU/kg PCC). Routine hematoma evacuation surgery cannot be advocated, yet new minimally invasive strategies provide promising results. In patients with acute occlusive hydrocephalus, an external ventricular drain should be placed and utilizing intraventricular lysis appears safe, reduces mortality, and is associated with improved functional outcome. Adding lumbar drainage to this treatment strategy may reduce permanent shunt dependency. The sum of treatment measures and specialized care at high-volume centers improves outcome in patients with ICH.

Recent Advances in the Acute Management of Intracerebral Hemorrhage

Primary intracerebral hemorrhage (ICH) is a common, devastating disease that lacks an effective specific treatment. Mortality is high, functional outcomes are poor, and these have not substantially changed for decades. There is, therefore, considerable opportunity for advancement in the management of ICH. In recent years, a significant amount of research has begun to address this gap. This article is aimed at updating neurologists on the most clinically relevant contemporary research.

Hemoglobin enhances miRNA-144 expression and autophagic activation mediated inflammation of microglia via mTOR pathway

Intracerebral hemorrhage promotes autophagic activation of microglia and enhances neuroinflammation. MiRNAs are key factors to autophagy, contributed to negatively and posttranscriptionally regulate gene expression and function. However, the specific miRNAs involved in the intracerebral hemorrhage mediated microglia autophagic activation are unidentified. In this experiment, microglia was treated with hemoglobin. And then, miRNA-144 expression, autophagic activation and inflammation of microglia were detected. In addition, the mTOR target of miRNA-144 and its regulation were identified. Our data demonstrated that hemoglobin promoted miRNA-144 expression and autophagic activation mediated inflammation. Additionally, miRNA-144 targeted mTOR by directly interacting with the 3' untranslated regions (UTRs), mutations of the binding sites abolish the miRNA-144 responsiveness. Overexpression of mTOR decreased autophagic activation and inflammation of microglia. Therefore, our results suggested that miRNA-144 contributed to hemoglobin mediated autophagic activation and inflammation of microglia via mTOR pathway. And miRNA based treatment provided novel therapeutical strategy for intracerebral hemorrhage.

Jugular Venous Reflux Is Associated with Perihematomal Edema after Intracerebral Hemorrhage

The purpose of this study was to determine whether jugular venous reflux (JVR) is associated with perihematomal edema (PHE) in individuals with intracerebral hemorrhage (ICH). Patients with spontaneous supratentorial ICH within 72 h of symptom onset were enrolled. Baseline brain computed tomography (CT) scan was performed, with a follow-up CT examination at 12 ± 3 days after onset. Jugular venous color Doppler ultrasound was performed at 12 ± 3 days after onset to examine the JVR status. A total of 65 patients with ICH were enrolled. In logistic regression analysis, absolute PHE volume was significantly associated with JVR (OR, 5.46; 95% CI, 1.04–28.63; p = 0.044) and baseline hematoma volume (OR, 1.14; 95% CI, 1.03–1.26; p = 0.009) within 72 h of onset. It was also correlated with JVR (OR, 15.32; 95% CI, 2.52–92.99; p = 0.003) and baseline hematoma volume (OR, 1.14; 95% CI, 1.04–1.24; p = 0.006) at 12 ± 3 days after onset. In a similar manner, relative PHE volume was significantly associated with JVR (OR, 14.85; 95% CI, 3.28–67.17; p < 0.001) within 72 h of onset and at 12 ± 3 days after onset (OR, 5.87; 95% CI, 1.94–17.77; p = 0.002). JVR is associated with both absolute and relative PHE volumes after ICH.

Medical management of intracerebral haemorrhage

The global burden of intracerebral haemorrhage (ICH) is enormous. Developing evidence-based management strategies for ICH has been hampered by its diverse aetiology, high case fatality and variable cooperative organisation of medical and surgical care. Progress is being made through the conduct of collaborative multicentre studies with the large sample sizes necessary to evaluate therapies with realistically modest treatment effects. This narrative review describes the major consequences of ICH and provides evidence-based recommendations to support decision-making in medical management.