Platelet activation and aggregation after aneurysmal subarachnoid hemorrhage

Platelet mitochondria, a potent immune mediator in neurological diseases

Dysfunction of the immune response is regarded as a prominent feature of neurological diseases, including neurodegenerative diseases, malignant tumors, acute neurotraumatic insult, and cerebral ischemic/hemorrhagic diseases. Platelets play a fundamental role in normal hemostasis and thrombosis. Beyond those normal functions, platelets are hyperactivated and contribute crucially to inflammation and immune responses in the central nervous system (CNS). Mitochondria are pivotal organelles in platelets and are responsible for generating most of the ATP that is used for platelet activation and aggregation (clumping). Notably, platelet mitochondria show marked morphological and functional alterations under heightened inflammatory/oxidative stimulation. Mitochondrial dysfunction not only leads to platelet damage and apoptosis but also further aggravates immune responses. Improving mitochondrial function is hopefully an effective strategy for treating neurological diseases. In this review, the authors discuss the immunomodulatory roles of platelet-derived mitochondria (PLT-mitos) in neurological diseases and summarize the neuroprotective effects of platelet mitochondria transplantation.

Cortical Spreading Depolarization and Delayed Cerebral Ischemia; Rethinking Secondary Neurological Injury in Subarachnoid Hemorrhage

Poor outcomes in Subarachnoid Hemorrhage (SAH) are in part due to a unique form of secondary neurological injury known as Delayed Cerebral Ischemia (DCI). DCI is characterized by new neurological insults that continue to occur beyond 72 h after the onset of the hemorrhage. Historically, it was thought to be a consequence of hypoperfusion in the setting of vasospasm. However, DCI was found to occur even in the absence of radiographic evidence of vasospasm. More recent evidence indicates that catastrophic ionic disruptions known as Cortical Spreading Depolarizations (CSD) may be the culprits of DCI. CSDs occur in otherwise healthy brain tissue even without demonstrable vasospasm. Furthermore, CSDs often trigger a complex interplay of neuroinflammation, microthrombi formation, and vasoconstriction. CSDs may therefore represent measurable and modifiable prognostic factors in the prevention and treatment of DCI. Although Ketamine and Nimodipine have shown promise in the treatment and prevention of CSDs in SAH, further research is needed to determine the therapeutic potential of these as well as other agents.

Compartmental Cerebrospinal Fluid Events Occurring after Subarachnoid Hemorrhage: An "Heparin Oriented" Systematic Review

Subarachnoid hemorrhage (SAH) represents a severe acute event with high morbidity and mortality due to the development of early brain injury (EBI), secondary delayed cerebral ischemia (DCI), and shunt-related hydrocephalus. Secondary events (SSE) such as neuroinflammation, vasospasm, excitotoxicity, blood-brain barrier disruption, oxidative cascade, and neuronal apoptosis are related to DCI. Despite improvement in management strategies and therapeutic protocols, surviving patients frequently present neurological deficits with neurocognitive impairment. The aim of this paper is to offer to clinicians a practical review of the actually documented pathophysiological events following subarachnoid hemorrhage. To reach our goal we performed a literature review analyzing reported studies regarding the mediators involved in the pathophysiological events following SAH occurring in the cerebrospinal fluid (CSF) (hemoglobin degradation products, platelets, complement, cytokines, chemokines, leucocytes, endothelin-1, NO-synthase, osteopontin, matricellular proteins, blood-brain barrier disruption, microglia polarization). The cascade of pathophysiological events secondary to SAH is very complex and involves several interconnected, but also distinct pathways. The identification of single therapeutical targets or specific pharmacological agents may be a limited strategy able to block only selective pathophysiological paths, but not the global evolution of SAH-related events. We report furthermore on the role of heparin in SAH management and discuss the rationale for use of intrathecal heparin as a pleiotropic therapeutical agent. The combination of the anticoagulant effect and the ability to interfere with SSE theoretically make heparin a very interesting molecule for SAH management.

The pCONUS2 and pCONUS2 HPC Neck Bridging Devices : Results from an International Multicenter Retrospective Study

INTRODUCTION

Bifurcation aneurysms represent an ongoing endovascular challenge with a variety of techniques and devices designed to address them. We present our multicenter series of the pCONUS2 and pCONUS2 HPC devices when treating bifurcation aneurysms.

METHODS

We performed a retrospective review of our prospectively maintained databases at 3 tertiary neurointerventional centers to identify all patients who underwent coil embolization with the pCONUS2 or pCONUS2 HPC device between February 2015 and August 2021. We recorded baseline demographics, aneurysm data, complications, immediate and delayed angiographic results.

RESULTS

We identified 55 patients with 56 aneurysms, median age 63 years (range 42-78 years), 67.3% female (n = 37). The commonest aneurysm location was the MCA bifurcation (n = 40, 71.4%). Average dome height was 8.9 ± 4.2 mm (range 3.2-21.5 mm), average neck width 6.4 ± 2.5 mm (range 2.6-14 mm), and average aspect ratio 1.3 ± 0.6 (range 0.5-3.3). The pCONUS2 was used in 64.3% and the pCONUS2 HPC in 35.7%. The procedural technical success rate was 98.2%. Intraoperative complications occurred in 5 cases (8.9%), 4 of which were related to the coils with partial thrombus formation on the pCONUS2 HPC seen in 1 case that was resolved with heparin. In relation to the procedure and treatment of the aneurysm the overall permanent morbidity was 1.8% (n = 1/55) and mortality 0%. Delayed angiographic follow-up (48 aneurysms) at median 12 months postprocedure (range 3-36 months) demonstrated adequate occlusion of 83.4% of aneurysms.

CONCLUSION

The pCONUS2 and pCONUS2 HPC devices carry a high technical success rate, low complication and retreatment rate, and good rates of adequate occlusion. Larger prospective confirmatory studies are required.

XGBoost Machine Learning Algorithm for Prediction of Outcome in Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Patients suffered aneurysmal subarachnoid hemorrhage (aSAH) usually develop poor survival and functional outcome. Evaluating aSAH patients at high risk of poor outcome is necessary for clinicians to make suitable therapeutical strategy. This study is conducted to develop prognostic model using XGBoost (extreme gradient boosting) algorithm in aSAH.

METHODS

A total of 351 aSAH patients admitted to West China hospital were identified. Patients were divided into training set and test set with ratio of 7:3 to testify the predictive value of XGBoost based prognostic model. Additionally, logistic regression model was also constructed and compared with XGBoost based model. Area under the receiver operating characteristic curve (AUC), sensitivity and specificity were calculated to evaluate the value of XGBoost and logistic regression.

RESULTS

There were 74 (21.1%) non-survivors and 148 (42.1%) patients with unfavorable functional outcome. Non-survivors had older age (p=0.025), lower Glasgow coma scale (GCS) (p<0.001), higher World Federation of Neurosurgical Societies WFNS score (p<0.001), mFisher score (p<0.001). The incidence of intraventricular hemorrhage (IVH) (p=0.025) and delayed cerebral ischemia (DCI) (p<0.001) was higher in non-survivors than survivors. The AUC of XGBoost model for predicting mortality and unfavorable functional outcome were 0.950 and 0.958, which were higher than 0.767 and 0.829 of logistic regression model.

CONCLUSION

XGBoost based model is more precise than logistic regression model in predicting outcome of aSAH patients. Using XGBoost prognostic model is helpful for clinicians to identify high-risk aSAH patients and therefore strengthen medical care.

Systemic Immune-Inflammation Index Predicts Delayed Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Delayed cerebral vasospasm is a feared complication of aneurysmal subarachnoid hemorrhage (SAH).

OBJECTIVE

To investigate the relationship of systemic inflammation, measured using the systemic immune-inflammation (SII) index, with delayed angiographic or sonographic vasospasm. We hypothesize that early elevations in SII index serve as an independent predictor of vasospasm.

METHODS

We retrospectively reviewed the medical records of 289 SAH patients for angiographic or sonographic evidence of delayed cerebral vasospasm. SII index [(neutrophils × platelets/lymphocytes)/1000] was calculated from laboratory data at admission and dichotomized based on whether or not the patient developed vasospasm. Multivariable logistic regression and receiver operating characteristic (ROC) analysis were performed to determine the ability of SII index to predict the development of vasospasm.

RESULTS

A total of 246 patients were included in our study, of which 166 (67.5%) developed angiographic or sonographic evidence of cerebral vasospasm. Admission SII index was elevated for SAH in patients with vasospasm compared to those without (P < .001). In univariate logistic regression, leukocytes, neutrophils, lymphocytes, neutrophil-lymphocyte ratio (NLR), and SII index were associated with vasospasm. After adjustment for age, aneurysm location, diabetes mellitus, hyperlipidemia, and modified Fisher scale, SII index remained an independent predictor of vasospasm (odds ratio 1.386, P = .003). ROC analysis revealed that SII index accurately distinguished between patients who develop vasospasm vs those who do not (area under the curve = 0.767, P < .001).

CONCLUSION

Early elevation in SII index can independently predict the development of delayed cerebral vasospasm in aneurysmal SAH.

Role of platelets in the pathogenesis of delayed injury after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) patients develop delayed cerebral ischemia and delayed deficits (DCI) within 2 weeks of aneurysm rupture at a rate of approximately 30%. DCI is a major contributor to morbidity and mortality after SAH. The cause of DCI is multi-factorial with contributions from microthrombi, blood vessel constriction, inflammation, and cortical spreading depolarizations. Platelets play central roles in hemostasis, inflammation, and vascular function. Within this review, we examine the potential roles of platelets in microthrombi formation, large artery vasospasm, microvessel constriction, inflammation, and cortical spreading depolarization. Evidence from experimental and clinical studies is provided to support the role(s) of platelets in each pathophysiology which contributes to DCI. The review concludes with a suggestion for future therapeutic targets to prevent DCI after aSAH.

Early clinical experience with the p48MW HPC and p64MW HPC flow diverters in the anterior circulation aneurysm using single anti-platelet treatment

Background

The p64MW HPC and p48MW HPC flow diverters have reduced thrombogenicity due to hydrophilic coating. The purpose of this study was to evaluate its safety and efficacy in Mongolian patients under single antiplatelet therapy (SAPT) with prasugrel.

Materials and methods

We performed a retrospective review of patients enrolled into our prospectively maintained database to identify all patients treated with either the p48MW HPC or p64MW HPC under SAPT. We recorded baseline demographics, aneurysm size and location, procedural complications, angiographic and clinical results.

Results

24 patients, (female = 21, 87.5%), age 48.2 ± 11.6 years (range 25–63) underwent treatment of 30 aneurysms with either p64MW HPC or p48MW HPC. All aneurysms were saccular with dome width 8.2 ± 6.5 (range 1.6–26.0 mm) and dome height 7.6 ± 6.7 (range 1.6–30.0 mm). None of the aneurysms were previously treated. The average PRU was 54.6 ± 31.2 (range 1–127) on pre-operative VerifyNow testing. Angiographic follow-up was available for 13 patients (17 aneurysms), 183 ± 36 days post-procedure, at which point 64.7% of aneurysms (n = 11/17) were completely occluded and 11.8% (n = 2/17) had only neck remnants resulting in 76.5% of aneurysms being adequately occluded A single intra-operative complication (4.2%) occurred however all patients were mRS ≤1 at last follow-up. There were two post-operative complications neither of which resulted in permanent neurological morbidity. There were no instances of post-operative aneurysmal rupture or delayed parenchymal haemorrhage. The overall mortality was 0%.

Conclusion

The efficacy and safety of p64MW HPC coated devices under SAPT is similar to uncoated flow diverters that require DAPT.

Flow Diversion for Reconstruction of Intradural Vertebral Artery Dissecting Aneurysms Causing Subarachnoid Hemorrhage-A Retrospective Study From Four Neurovascular Centers

Objective: Dissecting aneurysms (DAs) of the vertebrobasilar territory manifesting with subarachnoid hemorrhage (SAH) are associated with significant morbi-mortality, especially in the case of re-hemorrhage. Sufficient reconstruction of the affected vessel is paramount, in particular, if a dominant vertebral artery (VA) is impacted. Reconstructive options include stent-assisted coiling and flow diversion (FD). The latter is technically less challenging and does not require catheterization of the fragile aneurysm. Our study aims to report a multicentric experience with FD for reconstruction of DA in acute SAH.

Materials and Methods: This retrospective study investigated 31 patients (age: 30–78 years, mean 55.5 years) who had suffered from SAH due to a DA of the dominant VA. The patients were treated between 2010 and 2020 in one of the following German neurovascular centers: University Hospital Leipzig, Katharinenhospital Stuttgart, BG Hospital Bergmannstrost Halle/Saale, and Heinrich-Braun-Klinikum Zwickau. Clinical history, imaging, implanted devices, and outcomes were reviewed for the study.

Results: Reconstruction with flow-diverting stents was performed in all cases. The p64 was implanted in 14 patients; one of them required an additional balloon-expandable stent to reconstruct severe stenosis in the target segment. One case demanded additional liquid embolization after procedural rupture, and in one case, p64 was combined with a PED. Further 13 patients were treated exclusively with the PED. The p48MW-HPC was used in two patients, one in combination with two additional Silk Vista Baby (SVB). Moreover, one patient was treated with a single SVB, one with a SILK+. Six patients died [Glasgow Outcome Scale (GOS) 1]. Causes of death were periprocedural re-hemorrhage, thrombotic occlusion of the main pulmonary artery, and delayed parenchymal hemorrhage. The remaining three patients died in the acute–subacute phase related to the severity of the initial hemorrhage and associated comorbidities. One patient became apallic (GOS 2), whereas two patients had severe disability (GOS 3) and four had moderate disability (GOS 4). Eighteen patients showed a complete recovery (GOS 5).

Conclusion: Reconstruction of VA-DA in acute SAH with flow-diverting stents is a promising approach. However, the severity of the condition is reflected by high overall morbi-mortality, even despite technically successful endovascular treatment.

Platelet Receptor Activity for Predicting Survival in Patients with Intracranial Bleeding

Blood coagulation disorders in patients with intracranial bleeding as a result of head injuries or ruptured aneurysms are a diagnostic and therapeutic problem and appropriate assessments are needed to limit CNS damage and to implement preventive measures. The aim of the study was to monitor changes in platelet aggregation and to assess the importance of platelet dysfunction for predicting survival. Platelet receptor function analysis was performed using the agonists arachidonic acid (ASPI), adenosine diphosphate (ADP), collagen (COL), thrombin receptor activating protein (TRAP), ristocetin (RISTO) upon admission to the ICU and on days 2, 3, and 5. On admission, the ASPI, ADP, COL, TRAP, and RISTO tests indicated there was reduced platelet aggregation, despite there being a normal platelet count. In ‘Non-survivors’, the platelet response to all agonists was suppressed throughout the study period, while in ‘Survivors’ it improved. Measuring platelet function in ICU patients with intracranial bleeding is a strong predictor related to outcome: patients with impaired platelet aggregation had a lower 28-day survival rate compared to patients with normal platelet aggregation (log-rank test p = 0.014). The results indicated that measuring platelet aggregation can be helpful in the early detection, diagnosis, and treatment of bleeding disorders.

Aneurysm Treatment in Acute SAH with Hydrophilic-Coated Flow Diverters under Single-Antiplatelet Therapy: A 3-Center Experience

BACKGROUND AND PURPOSE

In certain clinical circumstances, dual-antiplatelet therapy can be problematic in patients with acute SAH. In some aneurysms, however, flow-diverting stents are the ideal therapeutic option. We report our experience with ruptured intracranial aneurysms treated with flow diverters with hydrophilic coating (p48 MW HPC and p64 MW HPC) under single-antiplatelet therapy.

MATERIALS AND METHODS

Patients were treated with either flow-diverter placement alone or a flow diverter and additional coiling. Due to the severity of the hemorrhage, the potential for periprocedural rehemorrhage, and the potential for additional surgical interventions, a single-antiplatelet regimen was used in all patients.

RESULTS

Thirteen aneurysms were treated in 10 patients. The median age was 62 years; 5 patients were male. All had acute SAH due to aneurysm rupture. Four blood-blister, 2 dissecting, and 7 berrylike aneurysms were treated. Seven aneurysms were adjunctively coiled. Eight of the 10 patients received a single-antiplatelet protocol of aspirin, 1 patient was treated with prasugrel only, and 1 patient was treated with tirofiban first and then switched to the aspirin single-antiplatelet protocol. One device-related complication occurred, a thrombosis of an overstented branch. All stents, however, remained open at DSA, CTA, or MRA follow-up.

CONCLUSIONS

The implantation of flow diverters with reduced thrombogenicity due to hydrophilic surface coating under single-antiplatelet therapy seems to be an option in carefully selected cases of SAH due to aneurysm rupture.

Endovascular Treatment Strategy and Clinical Outcomes for Ruptured Blood Blister-Like Aneurysms of the Internal Carotid Artery Using Low-Profile Visualized Intraluminal Support Stent

OBJECTIVE

It is challenging to safely treat blood blister-like aneurysms (BBAs) of the internal carotid artery. Endovascular surgery has been reported, but the optimal strategy is yet to be established. We report our endovascular treatment strategy using the Low-profile Visualized Intraluminal Support (LVIS) stent.

METHODS

Twelve patients with ruptured BBAs including 1 patient with 2 separate aneurysmal bulges were treated from December 2017 to January 2020. Single LVIS stent-assisted coil embolization was performed as the initial treatment. If the coil could not be placed in the aneurysm, or follow-up angiography showed persistent filling or regrowth of the aneurysm, a second LVIS stent was deployed as an overlapping stent. Clinical characteristics, treatment details, and clinical outcomes were retrospectively examined.

RESULTS

Single stent-assisted coiling was performed in 8 patients (69%), 2 overlapping stents with coiling in 1 (8%), a single stent in 2 (15%), and 2 overlapping stents in 2 (15%). Three patients with persistent filling or regrowth of the aneurysm were re-treated with overlapping stents. Follow-up angiography confirmed complete occlusion in 12 aneurysms (92%). No re-rupture occurred. Postoperative symptomatic ischemia was confirmed in 4 patients (33%), and all 4 patients suffered severe subarachnoid hemorrhage. Modified Rankin scale was 0-2 in 8 patients (67%).

CONCLUSIONS

LVIS stent-assisted coil embolization is effective in preventing re-rupture of BBAs. However, the morphology of the aneurysm may change within a short period, so careful angiographic follow-up is needed. Appropriate preoperative antiplatelet administration and optimal timing of the treatment may reduce the risk of postoperative ischemic complication.

Antiplatelet therapy for the prevention of atherosclerosis in chronic kidney disease (ALTAS-CKD) patients: study protocol for a randomized clinical trial

BACKGROUND

Cardiovascular disease (CVD) is the most common complication and the leading cause of death in patients with chronic kidney disease (CKD). Accelerated atherosclerosis is a pathophysiological process that is vital to the occurrence of cardiovascular complications associated with CKD. Abnormal platelet activation is not only the leading cause of atherosclerosis but also plays a critical role in the occurrence of thrombotic events. Currently, antiplatelet drugs are commonly used as a secondary prevention strategy for high blood pressure, obesity, diabetes, and ischemic heart disease and can reduce the risk of CVD in the susceptible population. However, the benefits and evidence of using antiplatelet agents in patients with CKD remain controversial. This study aimed to determine whether antiplatelet therapy can safely prevent atherosclerosis in patients with CKD in the primary care setting.

METHODS/DESIGN

The ALTAS-CKD study is a multicenter, prospective, randomized, double-blind, placebo-controlled trial of 554 adult patients with stage 3-5 non-dialysis-dependent CKD recruited from 10 territory medical centers in China. A secured web-based computer randomization system will be used to administer aspirin 100 mg once daily or a matching inactive placebo for 36 months. The primary endpoint will be the occurrence of atherosclerosis, as measured by carotid ultrasonography. The secondary endpoints will be combined cardiovascular events, all-cause mortality, and 50% decrease in the estimated glomerular filtration rate. TRIAL REGISTRATION {2A}: Current controlled trials number: ChiCTR1900021393 . Registered on 18 February 2019.

Reactive Thrombocytosis in Non-aneurysmal Subarachnoid Hemorrhage

BACKGROUND

 The role of reactive thrombocytosis in non-aneurysmal subarachnoid hemorrhage (NA-SAH) is largely unexplored to date. Therefore, the impact of a quantitative thrombocyte dynamic in patients with NA-SAH and its clinical relevance were analyzed in the present study.

METHODS

 In this retrospective analysis, 113 patients with nontraumatic and NA-SAH treated between 2003 and 2015 at our institution were included. World Federation of Neurosurgical Societies admission status, cerebral vasospasm, delayed infarction, hydrocephalus, need for ventriculoperitoneal (VP) shunt, and Fisher grade were analyzed for their association with reactive thrombocytosis.

RESULTS

 Reactive thrombocytosis was not associated with hydrocephalus (p ≥ 0.05), need for VP shunt implantation (p ≥ 0.05), cerebral vasospasm (p ≥ 0.05), or delayed cerebral ischemia (p ≥ 0.05).

CONCLUSION

 Our study is the first to investigate the role of thrombocyte dynamics, reactive thrombocytosis, and the clinical course of NA-SAH patients. Our analysis showed no significant impact of thrombocyte count on NA-SAH sequelae.

Use of the pCONus HPC as an adjunct to coil occlusion of acutely ruptured aneurysms: early clinical experience using single antiplatelet therapy

Background

Coil occlusion has become the standard treatment for many ruptured aneurysms. However, specific aneurysm structures pose technical difficulties and may require the use of adjunctive neck-bridging devices, which necessitate the use of dual antiplatelet therapy. The hydrophilic polymer coating (pHPC, phenox) is a surface modification that inhibits platelet adhesion.

Objective

To present initial experience with the pCONUS HPC device as an adjunct to coil embolization for ruptured aneurysms using single antiplatelet therapy (SAPT).

Methods

All patients who were treated with the pCONUS HPC for ruptured aneurysms using SAPT were retrospectively identified. The occurrence of thromboembolic and hemorrhagic complications was recorded together with the angiographic and clinical follow-up details.

Results

Fifteen patients were identified (nine female) with a median age of 54 years (range 27–81). Six aneurysms were located at the anterior communicating artery, five at the middle cerebral artery bifurcation, two at the basilar artery bifurcation, one at the posterior communicating artery, and one involving the intradural internal carotid artery. Ten patients (66.6%) achieved modified Raymond–Roy classification I or II at post-treatment angiography, with 45.5% of patients having adequate occlusion (defined as complete occlusion or neck remnant) at follow-up. All patients received acetylsalicylic acid (ASA) as SAPT before and after the procedure. Intraprocedural thrombus formation was seen in three patients (20%), resolving in two patients after a bolus dose of eptifibatide, and one treated with mechanical aspiration. No clinical or radiological consequences were seen. There were no recurrent aneurysm ruptures. One patient died owing to cerebral vasospasm.

Conclusion

This initial clinical experience highlights the possibility and limitations of using the pCONUS HPC device in the treatment of complex ruptured aneurysm with ASA as SAPT. Randomized trials with longer follow-up in larger cohorts are underway.

The p48 Flow Modulation Device with Hydrophilic Polymer Coating (HPC) for the Treatment of Acutely Ruptured Aneurysms: Early Clinical Experience Using Single Antiplatelet Therapy

Background

Flow diversion (FD) remains a potential treatment option following aneurysmal subarachnoid hemorrhage (aSAH) when standard options may not be feasible. However, it should not be considered a first-line treatment due to the need for dual antiplatelet therapy (DAPT). The hydrophilic polymer coating on the p48MW flow diverter (HPC, phenox) is a surface modification that inhibits platelet adhesion. This study aims to report on our early single-center experience using the p48MW HPC (phenox) flow diverter with single antiplatelet therapy (SAPT) following an aSAH.

Materials and Methods

We retrospectively identified all patients who had been treated with the p48MW HPC for aSAH under SAPT. All patients treated within 30 days following an aSAH were included. Any occurrence of thromboembolic and hemorrhagic complications was recorded alongside angiographic and clinical follow-up details.

Results

Eight patients were identified. The mean interval between aSAH and FD was 6 days. Of the eight ruptured aneurysms, one was blister-like, one saccular, one mycotic, and the remaining five were dissecting aneurysms. Intraprocedural transient thrombus formation was observed in four patients (50%). Stent thrombosis was observed in one patient (12.5%) on day 3 with spontaneous recanalization after being switched onto DAPT. None of the aneurysms rebled after treatment. Two patients died due to cerebral vasospasm. Complete aneurysm occlusion had been achieved in all but one patient at angiographic follow-up (average 6 months).

Conclusions

This small series highlights the possibility and limitations of using the p48MW HPC with SAPT in ruptured aneurysms. Randomized trials with longer follow-up in larger cohorts are underway.

Exercise Training Enhances Platelet Mitochondrial Bioenergetics in Stroke Patients: A Randomized Controlled Trial

Exercise training (ET) may impact physical fitness by affecting mitochondrial functions. This study aimed to elucidate the effect of ET on aerobic capacity and platelet mitochondrial bioenergetics (MTB) in stroke patients. Among the 30 stroke patients who underwent the traditional rehabilitation program (TRP), 15 were randomly assigned to have ET (50-60% VO_2peak for 30 min/day, 5 days/week for 4 weeks), and those remaining received only the TRP (control group). The peak exercise capacity (VO_2peak) and platelet MTB, including oxidative phosphorylation (OXPHOS) and the electron transport chain (ETC), were measured through automatic gas analysis and high-resolution respirometry, respectively. The results demonstrated that ET significantly increased the VO_2peak (17.7%) and O₂ uptake efficiency slope (31.9%) but decreased the ventilation versus CO₂ production slope (-7.65%). Patients who underwent ET also had significantly enhanced platelet mitochondrial OXPHOS and ETC by activating the FADH2 (Complex II)-dependent pathway, but depressed plasma myeloperoxidase (-28.4%) and interleukin-6 levels (-29.9%). Moreover, changes in VO_2peak levels were positively correlated with changes in platelet OXPHOS and ETC capacities. In conclusion, ET increases the platelet MTB by enhancing Complex II activity in stroke patients. The exercise regimen also enhances aerobic fitness and depresses oxidative stress/pro-inflammatory status in stroke patients.

Inflammatory Responses Induced by the Rupture of Intracranial Aneurysms Are Modulated by miRNAs

Influence of an intracranial aneurysm (IA) rupture on the expression of miRNAs and the potential significance of the resulting changes remains poorly understood. We aimed to characterize the response to the IA rupture through the analysis of miRNAs in peripheral blood cells. Expression of small RNAs was investigated using deep transcriptome sequencing in patients in the acute phase of an IA rupture (first 72 h), in the chronic phase (3–15 months), and controls. A functional analysis and the potential interactions between miRNAs and target genes were investigated. We also measured the levels of proteins that were influenced by regulated miRNAs. We found that 106 mature miRNAs and 90 miRNA precursors were differentially expressed among the groups. The regulated miRNAs were involved in a variety of pathways, and the top pathway involved cytokine-cytokine receptor interactions. The identified miRNAs targeted the inflammatory factors HMGB1 and FASLG. Changes in their expression were detected at the mRNA and protein levels. IA rupture strongly influences the transcription profiles in peripheral blood cells. The regulated miRNAs were involved in the control of immune cell homeostasis. In summary, these results may aid in the elucidation of the molecular mechanisms that orchestrate the inflammatory response to IA rupture.

Thromboelastography with Platelet Mapping Detects Platelet Dysfunction in Patients with Aneurysmal Subarachnoid Hemorrhage with Rebleeding

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) has high rates of disability and mortality, and aneurysm rebleeding is associated with poor functional outcomes. Thrombelastography with platelet mapping (TEG-PM) measures platelet function; however, it has not yet been researched in aSAH. We aimed to use TEG-PM to detect changes in platelet function in patients with aSAH and the difference in patients with and without rebleeding.

METHODS

We retrospectively included patients with aSAH who underwent a TEG-PM test on admission. Rebleeding was diagnosed according to clinical and imaging data. TEG-PM data of patients with unruptured intracranial aneurysms (UIA) were also obtained as controls. Univariate and multivariate logistic regression models were performed to investigate the relationship between the platelet function and rebleeding.

RESULTS

A total of 245 aSAH patients and 32 UIA patients were included in our study. Compared with controls, patients with aSAH demonstrated higher arachidonic acid (AA) and adenosine diphosphate (ADP) inhibition of platelet function (P<0.05). Among them, 27 patients with Hunt-Hess grade IV or V were classified as the severe SAH group. There was a significant correlation between the severe SAH group and the degree of pathway inhibition (P<0.05). Furthermore, AA (Spearman's r=0.264, P<0.001) and ADP (Spearman's r=0.183, P=0.004) inhibition were elevated in Hunt-Hess grade-dependent manners. The AA (Spearman's r=0.169, P=0.008) and ADP (Spearman's r=0.233, P<0.001) inhibition were also significantly correlated with Fisher grade. Thirty-five patients (14.3%) suffered rebleeding. Rebleeding was significantly correlated with systolic blood pressure (P=0.011), diastolic blood pressure (P=0.008), Hunt-Hess grade (P=0.034), Fisher grade (P=0.015), AA inhibition (P<0.001), and ADP inhibition (P<0.001). Multivariate logistic regression analysis model revealed that both AA (P=0.037) and ADP inhibition (P=0.008) were independent determinants for rebleeding.

CONCLUSION

TEG-PM may assess platelet dysfunction in patients with aSAH, and the diminished platelet response to ADP and AA may be associated with rebleeding. These findings deserve further investigation.