An Outcome Model for Intravenous rt-PA in Acute Ischemic Stroke

Thrombolysis experience in Costa Rica compared against individual patient data from two randomized controlled trials

OBJECTIVES

We sought to compare thrombolysis outcomes from the Costa Rican Stroke Registry Program (CRSRP) with published individual patient data from NINDS and CLOTBUST-ER trials using matching and outcome modeling from randomized clinical trials (RCTs).

MATERIALS AND METHODS

A retrospective observational study matching subjects on baseline characteristics, from the CRSRP, the control arm of CLOTBUST-ER, and the interventional arm of NINDS trials. Day 7-10/discharge modified Rankin Score (mRS), and early mortality was compared between matched subjects. A mortality model derived from RCTs was developed, and outcomes were compared at similar baseline NIHSS scores. CRSRP symptomatic hemorrhage (SICH) rate was compared with an Ibero-American cohort (IAC).

RESULTS

Of 540 CRSRP patients, 351 received rt-PA under 3 hours and were matched with NINDS subjects yielding 292 pairs; 161 CRSRP subjects treated within 4.5 hours were matched with CLOTBUST-ER subjects resulting in 151 pairs. The proportion of patients achieving excellent outcomes (mRS 0-1) did not differ between CRSRP and either NINDS or CLOTBUST-ER (CRSRP vs NINDS: 36.6% vs 32.9%, p=0.3; CRSRP vs CLOTBUST-ER: 26.5% vs 24.5%, p=0.8). Mortality was higher for CRSRP vs CLOTBUST-ER (7.3% vs 0.7%, p=0.006), but not vs NINDS (6.5% vs 4.5%, p=0.4). A pooled mortality model derived from 15 RCTs representing 4410 patients (R²=0.39) showed CRSRP and NINDS within expected mortality, while CLOTBUST-ER showed lower than expected mortality. CRSRP SICH rate equaled IAC (5.7% vs 5.7%; p=0.9).

CONCLUSIONS

Functional outcomes and SICH of thrombolysed Costa Rican patients compared favorably with published datasets, with a potential increase in early mortality.

Pooled analysis suggests benefit of catheter-based hematoma removal for intracerebral hemorrhage

OBJECTIVE

To develop models of outcome for intracerebral hemorrhage (ICH) to identify promising and futile interventions based on their early phase results without need for correction for baseline imbalances.

METHODS

We developed a pooled outcome model from the control arms of randomized control trials and tested different interventions against the model at comparable baseline conditions. Eligible clinical trials and large case series were identified from multiple library databases. Models based on baseline factors reported in the control arms were tested for the ability to predict functional outcome (modified Rankin Scale score) and mortality. Interventions were grouped into blood pressure control, fibrinolytic-assisted hematoma evacuation, hemostatic medications, and neuroprotective agents. Statistical intervals around the model were generated at the p = 0.1 level to screen how each trial's outcome compared to expected outcome.

RESULTS

Fourteen control arms with 3,386 patients were used to develop 7 alternate models for functional outcome. The model incorporating baseline NIH Stroke Scale, age, and hematoma volume yielded the best fit (adjusted R ² = 0.89). All early phase treatments that eventually resulted in negative late phase trials were identified as negative by this method. Early phase fibrinolytic-assisted hematoma evacuation studies showed the most promise trending toward improved functional outcome with no suggestion of an increase in mortality, supporting its further study.

CONCLUSIONS

We successfully developed an outcome model for ICH that identified interventions destined to be negative while identifying a promising one. Such an approach may assist in prioritizing resources prior to multicenter trial.

Efficacy of Novel Carbon Nanoparticle Antioxidant Therapy in a Severe Model of Reversible Middle Cerebral Artery Stroke in Acutely Hyperglycemic Rats

INTRODUCTION

While oxidative stress can be measured during transient cerebral ischemia, antioxidant therapies for ischemic stroke have been clinically unsuccessful. Many antioxidants are limited in their range and/or capacity for quenching radicals and can generate toxic intermediates overwhelming depleted endogenous protection. We developed a new antioxidant class, 40 nm × 2 nm carbon nanoparticles, hydrophilic carbon clusters, conjugated to poly(ethylene glycol) termed PEG-HCCs. These particles are high-capacity superoxide dismutase mimics, are effective against hydroxyl radical, and restore the balance between nitric oxide and superoxide in the vasculature. Here, we report the effects of PEG-HCCs administered during reperfusion after transient middle cerebral artery occlusion (tMCAO) by suture in the rat under hyperglycemic conditions. Hyperglycemia occurs in one-third of stroke patients and worsens clinical outcome. In animal models, this worsening occurs largely by accelerating elaboration of reactive oxygen species (ROS) during reperfusion.

METHODS

PEG-HCCs were studied for their protective ability against hydrogen peroxide in b.End3 brain endothelial cell line and E17 primary cortical neuron cultures. In vivo, hyperglycemia was induced by streptozotocin injection 2 days before tMCAO. 58 Male Sprague-Dawley rats were analyzed. They were injected IV with PBS or PEG-HCCs (4 mg/kg 2×) at the time of recanalization after either 90- or 120-min occlusion. Rats were survived for up to 3 days, and infarct volume characteristics and neurological functional outcome (modified Bederson Score) were assessed.

RESULTS

PEG-HCCs were protective against hydrogen peroxide in both culture models. In vivo improvement was found after PEG-HCCs with 90-min ischemia with reduction in infarct size (42%), hemisphere swelling (46%), hemorrhage score (53%), and improvement in Bederson score (70%) (p = 0.068-0.001). Early high mortality in the 2-h in the PBS control group precluded detailed analysis, but a trend was found in improvement in all factors, e.g., reduction in infarct volume (48%; p = 0.034) and a 56% improvement in Bederson score (p = 0.055) with PEG-HCCs.

CONCLUSION

This nano-antioxidant showed some improvement in several outcome measures in a severe model of tMCAO when administered at a clinically relevant time point. Long-term studies and additional models are required to assess potential for clinical use, especially for patients hyperglycemic at the time of their stroke, as these patients have the worst outcomes.

Cornin protects SH‑SY5Y cells against oxygen and glucose deprivation‑induced autophagy through the PI3K/Akt/mTOR pathway

It has been reported that cornin may reduce neuronal death during cerebral ischemia; however, little is known about the molecular mechanism of the role of corninin autophagy in SH‑SY5Y neuronal cells. In the present study, oxygen‑glucose deprivation (OGD)‑treated cells were used as a cerebral ischemia model in vitro. The results demonstrated that cornin was able to reduce neuronal cell loss, increase the apoptosis regulator Bcl‑2/apoptosis regulator BAX ratio, and decrease the protein levels of caspase‑3. In addition, cornin decreased the microtubule‑associated proteins 1A/1B light chain 3B (LC3)‑II/LC3‑I ratio and beclin‑1 protein expression, and resulted in an upregulation in phosphorylated (p)‑RAC‑α serine/threonine‑protein kinase (Akt), p‑protein kinase mTOR (mTOR) in OGD‑treated SH‑SY5Y cells. Additionally, it was observed that following inhibition of PI3K/Akt by LY294002, the levels of p‑Akt and p‑mTOR were markedly decreased, and the LC3‑II/LC3‑I ratio and beclin‑1 were increased. Similarly, following inhibition of mTOR by rapamycin, LC3‑II/LC3‑I and Beclin‑1 were significantly increased in SH‑SY5Y cells. These results indicated that cornin protected SH‑SY5Y cells against OGD‑induced autophagy through the PI3K/Akt/mTOR pathway.

Prognostic Value of Diffusion-Weighted Imaging (DWI) Apparent Diffusion Coefficient (ADC) in Patients with Hyperacute Cerebral Infarction Receiving rt-PA Intravenous Thrombolytic Therapy

BACKGROUND The aim of this study was to investigate the potential value of apparent diffusion coefficient (ADC) of diffusion-weighted imaging (DWI) in the prognosis of patients with hyperacute cerebral infarction (HCI) receiving intravenous thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA). MATERIAL AND METHODS From June 2012 to June 2015, 58 cases of HCI (<6 h) undergoing rt-PA intravenous thrombolytic therapy (thrombolysis group) and 70 cases of HCI (<6 h) undergoing conventional antiplatelet and anticoagulant therapy (control group) in the same period were collected. DWI was conducted on all the subjects, and ADC maps were generated with Functool software to quantify ADC value. The clinical outcomes of HCI patients were observed for 3 months, and prognostic factors were analyzed. RESULTS Before thrombolysis treatment, the lesion area presented high signal intensity on DWI map and low signal intensity on ADC map, and gradually weakened signal intensity on DWI map and gradually enhanced signal intensity on ADC map were observed after thrombolysis. The ADC values of the thrombolysis group were significantly higher than those of the control group after treatment (24 h, 7 d, 30 d, and 90 d) (all P<0.05), and the ADC and rADC values in the thrombolysis group gradually increased over time (all P<0.05). Multiple logistic regression analysis showed that baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline rADC value, and stroke history were the independent factors for the prognosis of HIC patients with thrombolysis (all P<0.05). CONCLUSIONS The values of ADC and rADC may provide guidance in the prognosis of HCI patients receiving rt-PA, and the baseline rADC value is the protective factor for the prognosis of HCI patients receiving rt-PA.

A Post-stroke Therapeutic Regimen with Omega-3 Polyunsaturated Fatty Acids that Promotes White Matter Integrity and Beneficial Microglial Responses after Cerebral Ischemia

White matter injury induced by ischemic stroke elicits sensorimotor impairments, which can be further deteriorated by persistent proinflammatory responses. We previously reported that delayed and repeated treatments with omega-3 polyunsaturated fatty acids (n-3 PUFAs) improve spatial cognitive functions and hippocampal integrity after ischemic stroke. In the present study, we report a post-stroke n-3 PUFA therapeutic regimen that not only confers protection against neuronal loss in the gray matter but also promotes white matter integrity. Beginning 2 h after 60 min of middle cerebral artery occlusion (MCAO), mice were randomly assigned to receive intraperitoneal docosahexaenoic acid (DHA) injections (10 mg/kg, daily for 14 days), alone or in combination with dietary fish oil (FO) supplements starting 5 days after MCAO. Sensorimotor functions, gray and white matter injury, and microglial responses were examined up to 28 days after MCAO. Our results showed that DHA and FO combined treatment-facilitated long-term sensorimotor recovery and demonstrated greater beneficial effect than DHA injections alone. Mechanistically, n-3 PUFAs not only offered direct protection on white matter components, such as oligodendrocytes, but also potentiated microglial M2 polarization, which may be important for white matter repair. Notably, the improved white matter integrity and increased M2 microglia were strongly linked to the mitigation of sensorimotor deficits after stroke upon n-3 PUFA treatments. Together, our results suggest that post-stroke DHA injections in combination with FO dietary supplement benefit white matter restoration and microglial responses, thereby dictating long-term functional improvements.

Delayed Docosahexaenoic Acid Treatment Combined with Dietary Supplementation of Omega-3 Fatty Acids Promotes Long-Term Neurovascular Restoration After Ischemic Stroke

Prophylactic dietary intake of omega-3 polyunsaturated fatty acids (n-3 PUFAs) has been shown to remarkably ameliorate ischemic brain injury. However, the therapeutic efficacy of n-3 PUFA administration post-stroke, especially its impact on neurovascular remodeling and long-term neurological recovery, has not been fully characterized thus far. In this study, we investigated the effect of n-3 PUFA supplementation, as well as in combination with docosahexaenoic acid (DHA) injections, on long-term stroke outcomes. Mice were subjected to transient middle cerebral artery occlusion (MCAO) before randomly assigned to four groups to receive the following: (1) low dose of n-3 PUFAs as the vehicle control, (2) intraperitoneal DHA injections, (3) n-3 PUFA dietary supplement, or (4) combined treatment of (2) and (3). Neurological deficits and brain atrophy, neurogenesis, angiogenesis, and glial scar formation were assessed up to 28 days after MCAO. Results revealed that groups 2 and 3 showed only marginal reduction in post-stroke tissue loss and attenuation of cognitive deficits. Interestingly, group 4 exhibited significantly reduced tissue atrophy and improved cognitive functions compared to groups 2 and 3 with just a single treatment. Mechanistically, the combined treatment promoted post-stroke neurogenesis and angiogenesis, as well as reduced glial scar formation, all of which significantly correlated with the improved spatial memory in the Morris water maze. These results demonstrate an effective therapeutic regimen to enhance neurovascular restoration and long-term cognitive recovery in the mouse model of MCAO. Combined post-stroke DHA treatment and n-3 PUFA dietary supplementation thus may be a potential clinically translatable therapy for stroke or related brain disorders.

cPKCγ-Modulated Autophagy in Neurons Alleviates Ischemic Injury in Brain of Mice with Ischemic Stroke Through Akt-mTOR Pathway

We have reported that neuron-specific conventional protein kinase C (cPKC)γ is involved in the development of cerebral hypoxic preconditioning (HPC) and the neuroprotection against ischemic injuries, but its molecular mechanism is unclear. In this study, the adult and postnatal 24 h C57BL/6J wild-type (cPKCγ^+/+) and cPKCγ knockout (cPKCγ^-/-) mice were respectively used to establish the models of middle cerebral artery occlusion (MCAO)-induced ischemic stroke in vivo and oxygen-glucose deprivation (OGD)-treated primarily cultured cortical neurons as cell ischemia in vitro. The results showed that cPKCγ knockout could increase the infarct volume and neuronal cell loss in the peri-infarct region, and enhance the neurological deficits, the impaired coordination, and the reduced muscle strength of mice following 1 h MCAO/1-7 days reperfusion. Meanwhile, cPKCγ knockout significantly increased the conversion of LC3-I to LC3-II and beclin-1 protein expression, and resulted in more reductions in P-Akt, P-mTOR, and P-S6 phosphorylation levels in the peri-infarct region of mice with ischemic stroke. The autophagy inhibitor BafA1 could enhance or reduce neuronal cell loss in the peri-infarct region of cPKCγ^+/+ and cPKCγ^-/- mice after ischemic stroke. In addition, cPKCγ knockout and restoration could aggravate or alleviate OGD-induced neuronal ischemic injury in vitro through Akt-mTOR pathway-mediated autophagy. These results suggested that cPKCγ-modulated neuron-specific autophagy improves the neurological outcome of mice following ischemic stroke through the Akt-mTOR pathway, providing a potential therapeutic target for ischemic stroke.

Embracing Biological and Methodological Variance in a New Approach to Pre-Clinical Stroke Testing

High-profile failures in stroke clinical trials have discouraged clinical translation of neuroprotectants. While there are several plausible explanations for these failures, we believe that the fundamental problem is the way clinical and pre-clinical studies are designed and analyzed for heterogeneous disorders such as stroke due to innate biological and methodological variability that current methods cannot capture. Recent efforts to address pre-clinical rigor and design, while important, are unable to account for variability present even in genetically homogenous rodents. Indeed, efforts to minimize variability may lessen the clinical relevance of pre-clinical models. We propose a new approach that recognizes the important role of baseline stroke severity and other factors in influencing outcome. Analogous to clinical trials, we propose reporting baseline factors that influence outcome and then adapting for the pre-clinical setting a method developed for clinical trial analysis where the influence of baseline factors is mathematically modeled and the variance quantified. A new therapy's effectiveness is then evaluated relative to the pooled outcome variance at its own baseline conditions. In this way, an objective threshold for robustness can be established that must be overcome to suggest its effectiveness when expanded to broader populations outside of the controlled environment of the PI's laboratory. The method is model neutral and subsumes sources of variance as reflected in baseline factors such as initial stroke severity. We propose that this new approach deserves consideration for providing an objective method to select agents worthy of the commitment of time and resources in translation to clinical trials.

The role of hydrogen sulfide in stroke

Stroke is a kind of acute cerebrovascular disease characterized by the focal lack of neurological function, including ischemic stroke and hemorrhagic stroke. As society ages rapidly, stroke has become the second leading cause of disability and death, and also become the main threat to human health and life. In recent years, findings from increasing animal and clinical trials have supplied scientific evidences for the treatment of stroke. Hydrogen sulfide (H₂S), which has always been seen as a toxic gas, now has been thought to be the third gaseous signaling molecule following nitric oxide and carbon monoxide. Accumulating evidences indicate that H₂S plays an important role in stroke. Given that its neuroprotective effect is dose-dependent, only when its concentration is relatively low, H₂S can yield the neuroprotection, while high dose may lead to neurotoxicity. All these study results suggest that H₂S may offer a new promising application for the therapy of stroke. Here, our review will present the role of H₂S in stroke from its mechanism to animal and clinical studies.