FIGHT-PD: A feasibility study of periodized boxing training for Parkinson disease.

BACKGROUND: Boxing training has become a popular form of exercise for people with Parkinson disease (PD). There is a dearth of high-quality feasibility, safety, and efficacy data on boxing training for PD. Feasibility of Instituting Graduated High-intensity Training (FIGHT-PD) aimed to examine these features in a periodized boxing training program featuring high-intensity physical and cognitive demands. OBJECTIVE: To conduct a feasibility study, aiming to address deficiencies in the current knowledge base and to provide data for future studies. DESIGN: Single-arm, open-label feasibility. SETTING: University department and medical research institute. PARTICIPANTS: Ten people with early stage PD without contraindications to intense exercise, identified from a database of participants interested in boxing training. INTERVENTIONS: A 15-week exercise program with three 1-hour sessions per week, with each session including warmup and then rounds of noncontact boxing using a training device. Three distinct blocks of 5 weeks including active rest. Boxers Development: focus on training technique Boxers Cardio: increasing intensity, including high-intensity interval training Boxers Brain: focus on cognitively challenging dual task training MAIN OUTCOME MEASURES: Process, resource, and management measures including recruitment and retention rates, timelines and costs, and compliance with prescribed exercise targets. Clinical outcomes were safety (adverse events), training intensity (using heart rate and perceived exertion monitoring), tolerability (pain, fatigue, and sleep scores), and pre- and postprogram Unified Parkinson Disease Rating Scale (UPDRS-III). RESULTS: Among 10 participants from a pool of 82 (recruitment rate = 12%), there were no withdrawals; 348/360 workouts were completed (adherence = 97.7%); 4/348 (1.1%) workouts were missed due to minor injury. Nine of 10 participants showed improvement in UPDRS motor score. CONCLUSIONS: FIGHT-PD provides a depth of feasibility and safety data, methodological detail, and preliminary results that is not described elsewhere and could provide a useful basis for future studies of boxing training for PD.

Ultra-Long Transfers for Endovascular Thrombectomy-Mission Impossible?: The Australia-New Zealand Experience.

BACKGROUND: Endovascular thrombectomy (EVT) access in remote areas is limited. Preliminary data suggest that long distance transfers for EVT may be beneficial; however, the magnitude and best imaging strategy at the referring center remains uncertain. We hypothesized that patients transferred >300 miles would benefit from EVT, achieving rates of functional independence (modified Rankin Scale [mRS] score of 0-2) at 3 months similar to those patients treated at the comprehensive stroke center in the randomized EVT extended window trials and that the selection of patients with computed tomography perfusion (CTP) at the referring site would be associated with ordinal shift toward better outcomes on the mRS. METHODS: This is a retrospective analysis of patients transferred from 31 referring hospitals >300 miles (measured by the most direct road distance) to 9 comprehensive stroke centers in Australia and New Zealand for EVT consideration (April 2016 through May 2021). RESULTS: There were 131 patients; the median age was 64 [53-74] years and the median baseline National Institutes of Health Stroke Scale score was 16 [12-22]. At baseline, 79 patients (60.3%) had noncontrast CT+CT angiography, 52 (39.7%) also had CTP. At the comprehensive stroke center, 114 (87%) patients underwent cerebral angiography, and 96 (73.3%) proceeded to EVT. At 3 months, 62 patients (48.4%) had an mRS score of 0 to 2 and 81 (63.3%) mRS score of 0 to 3. CTP selection at the referring site was not associated with better ordinal scores on the mRS at 3 months (mRS median of 2 [1-3] versus 3 [1-6] in the patients selected with noncontrast CT+CT angiography, P=0.1). Nevertheless, patients selected with CTP were less likely to have an mRS score of 5 to 6 (odds ratio 0.03 [0.01-0.19]; P<0.01). CONCLUSIONS: In selected patients transferred >300 miles, there was a benefit for EVT, with outcomes similar to those treated in the comprehensive stroke center in the EVT extended window trials. Remote hospital CTP selection was not associated with ordinal mRS improvement, but was associated with fewer very poor 3-month outcomes.

Impact of poly-arginine peptides R18D and R18 on alteplase and tenecteplase thrombolysis in vitro, and neuroprotective stability to proteolysis.

The poly-arginine peptides R18D and R18 represent novel potential neuroprotective treatments for acute ischaemic stroke. Here we examined whether R18D and R18 had any significant effects on the thrombolytic activity of alteplase (tPA) and tenecteplase (TNK) on clots formed from whole blood in an in vitro thrombolysis plate assay. R18D and R18 were examined at concentrations of 0.25, 0.5, 1, 2, 4, 8 and 16 µM during the 1-h thrombolytic assay. We also included the well-characterised neuroprotective NA-1 peptide as a control. R18D, R18 and NA-1 all reduced tPA or TNK percentage clot lysis by 0-9.35%, 0-3.44% and 0-4.8%, respectively. R18D, R18 and NA-1 had a modest and variable effect on the lag time, increasing the time to the commencement of thrombolysis by 0-9.9 min, 0-5.53 min and 0-7.16 min, respectively. Lastly, R18 and NA-1 appeared to increase the maximal activity of the thrombolysis reaction. In addition, the in vitro anti-excitotoxic neuroprotective efficacy of R18D and R18 was not affected by pre-incubation for 1-2 h or overnight with tPA or TNK, whereas only R18D retained high anti-excitotoxic neuroprotective efficacy when pre-incubated in a synthetic trypsin (TrypLE Express). The present in vitro findings suggest that neither R18D or R18 when co-administered with the thrombolytic inducing agents tPA or TNK are likely to have a significant impact when used clinically during clot thrombolysis and confirm the superior proteolytic stability of the R18D peptide.

Mechanical thrombectomy is efficacious in patients with pre-stroke moderate disability.

INTRODUCTION: Patients with ischaemic stroke due to large vessel occlusion (LVO) can be treated successfully with mechanical thrombectomy (MT) and/or intravenous thrombolysis. In the landmark trials, MT was only performed for those with no functional disability prior to stroke (mRS 0-2). There are limited data available regarding clinical outcomes for patients with pre-stroke moderate disability (mRS ≥ 3). The aims of this study were to analyse the clinical outcomes and financial implications in regard to accommodation costs of performing MT in patients with pre-stroke mRS = 3. METHODS: An observational cohort study was performed of 802 patients with anterior circulation LVO ischaemic stroke who underwent MT between October 2016 and January 2020 at three tertiary hospitals. Patient demographics, premorbid mRS, stroke and interventional data, 90-day mRS and accommodation situation were recorded. RESULTS: Eighty-two patients with anterior circulation LVO ischaemic stroke were pre-stroke mRS 3. 38% had a good clinical outcome, as defined by mRS 3 at 90 days. Mortality rate was 38%. The majority of patients presented from home (83%) and greater than one third of those returned home during the 90 days post treatment. 81% of patients had no increase in accommodation cost at 90 days. CONCLUSION: Patients with pre-stroke moderate disability may benefit from MT if they are appropriately selected. This may result in fewer patients requiring nursing home placement and less financial burden on the public health system, indicating significant savings are possible.

Comparative Assessment of the Proteolytic Stability and Impact of Poly-Arginine Peptides R18 and R18D on Infarct Growth and Penumbral Tissue Preservation Following Middle Cerebral Artery Occlusion in the Sprague Dawley Rat.

Poly-arginine peptides R18 and R18D have previously been demonstrated to be neuroprotective in ischaemic stroke models. Here we examined the proteolytic stability and efficacy of R18 and R18D in reducing infarct core growth and preserving the ischaemic penumbra following middle cerebral artery occlusion (MCAO) in the Sprague Dawley rat. R18 (300 or 1000 nmol/kg), R18D (300 nmol/kg) or saline were administered intravenously 10 min after MCAO induced using a filament. Serial perfusion and diffusion-weighted MRI imaging was performed to measure changes in the infarct core and penumbra from time points between 45- and 225-min post-occlusion. Repeated measures analyses of infarct growth and penumbral tissue size were evaluated using generalised linear mixed models (GLMMs). R18D (300 nmol/kg) was most effective in slowing infarct core growth (46.8 mm3 reduction; p < 0.001) and preserving penumbral tissue (21.6% increase; p < 0.001), followed by R18 at the 300 nmol/kg dose (core: 29.5 mm3 reduction; p < 0.001, penumbra: 12.5% increase; p < 0.001). R18 at the 1000 nmol/kg dose had a significant impact in slowing core growth (19.5 mm3 reduction; p = 0.026), but only a modest impact on penumbral preservation (6.9% increase; p = 0.062). The in vitro anti-excitotoxic neuroprotective efficacy of R18D was also demonstrated to be unaffected when preincubated for 1-3 h or overnight, in a cell lysate prepared from dying neurons or with the proteolytic enzyme, plasmin, whereas the neuroprotective efficacy of R18 was significantly reduced after a 2-h incubation. These findings highlight the capacity of poly-arginine peptides to reduce infarct growth and preserve the ischaemic penumbra, and confirm the superior efficacy and proteolytic stability of R18D, which indicates that this peptide is likely to retain its neuroprotective properties when co-administered with alteplase during thrombolysis for acute ischaemic stroke.

Being a patient with early stage Parkinson disease: reaction to the diagnosis and management.

This personal viewpoint, written by a neurologist with Parkinson disease (PD), is to provide a patient's perspective, to accompany the clinical perspective in this issue of the Intenal Medicine Journal entitled 'Approach to the patient with early stage Parkinson disease'. The aim is to provide a personal insight into the numerous issues surrounding early diagnosis and management of PD, from the position of being a physician patient.

Sleep-disordered breathing in patients with stroke-induced dysphagia.

This study examined the nature and characteristics of sleep-disordered breathing, including obstructive sleep apnea and central sleep apnea, in patients with post-stroke dysphagia, to determine the demographic, anthropometric and clinical variables that were associated with sleep-disordered breathing. Thirty-nine patients diagnosed with acute stroke (28 males and 11 females with a mean age of 72.3 ± 10.0 years) underwent overnight polysomnography (within 3.9 ± 1.6 days after admission). Sleep-disordered breathing was described by the apnea-hypopnea index and its obstructive and central components by the obstructive apnea-hypopnea index and central apnea-hypopnea index, respectively. Severity of dysphagia was assessed using the Mann Assessment of Swallowing Ability score. Severity of stroke and functional dependence were assessed by the National Institute of Health Stroke Scale and the modified Barthel index, respectively. Most of the cohort (87%) had moderate-to-severe dysphagia (Mann Assessment of Swallowing Ability of 143.2 ± 19.9). Sleep-disordered breathing (apnea-hypopnea index ≥ 5 events/hr) was present in 38 participants (97%) with a mean apnea-hypopnea index of 37.5 ± 24.4 events/hr. Sleep-disordered breathing was predominantly obstructive in nature, with a mean obstructive apnea-hypopnea index and central apnea-hypopnea index of 19.6 ± 15.7 and 11.4 ± 17.6 events/hr, respectively. Multivariate linear regression analyses showed that the apnea-hypopnea index was associated with sex (p = .0001), body mass index (p = .029) and the modified Barthel index (p = .006); the obstructive apnea-hypopnea index was associated with the Mann Assessment of Swallowing Ability (p = .006), sex (p = .004) and body mass index (p = .015) and had a nonlinear relationship with the modified Barthel index (p = .019); and the central apnea-hypopnea index was associated with sex (p = .027) and the modified Barthel index (p = .019). The present study showed that dysphagia severity was associated with obstructive sleep apnea severity and this association was independent of sex, modified Barthel index and body mass index. However, stroke-induced dysphagia was not associated with central sleep apnea or overall sleep-disordered breathing.

Preventive antibiotic therapy in acute stroke patients: A systematic review and meta-analysis of individual patient data of randomized controlled trials.

Introduction: Infection after stroke is associated with unfavorable outcome. Randomized controlled studies did not show benefit of preventive antibiotics in stroke but lacked power for subgroup analyses. Aim of this study is to assess whether preventive antibiotic therapy after stroke improves functional outcome for specific patient groups in an individual patient data meta-analysis. Patients and methods: We searched MEDLINE (1946-7 May 2021), Embase (1947-7 May 2021), CENTRAL (17th September 2021), trial registries, cross-checked references and contacted researchers for randomized controlled trials of preventive antibiotic therapy versus placebo or standard care in ischemic or hemorrhagic stroke patients. Meta-analysis was performed by a one-step and two-step approach. Primary outcome was functional outcome adjusted for age and stroke severity. Secondary outcomes were infections and mortality. Results: 4197 patients from nine trials were included. Preventive antibiotic therapy was not associated with a shift in functional outcome (mRS) at 3 months (OR1.13, 95%CI 0.98-1.31) or unfavorable functional outcome (mRS 3-6) (OR0.85, 95%CI 0.60-1.19). Preventive antibiotics did not improve functional outcome in pre-defined subgroups (age, stroke severity, timing and type of antibiotic therapy, pneumonia prediction scores, dysphagia, type of stroke, and type of trial). Preventive antibiotics reduced infections (276/2066 (13.4%) in the preventive antibiotic group vs. 417/2059 (20.3%) in the control group, OR 0.60, 95% CI 0.51-0.71, p < 0.001), but not pneumonia (191/2066 (9.2%) in the preventive antibiotic group vs. 205/2061 (9.9%) in the control group (OR 0.92 (0.75-1.14), p = 0.450). Discussion and conclusion: Preventive antibiotic therapy did not benefit any subgroup of patients with acute stroke and currently cannot be recommended.

Factors Associated With 90-Day Readmission After Stroke or Transient Ischemic Attack: Linked Data From the Australian Stroke Clinical Registry.

Background and Purpose- Readmissions after stroke are common and appear to be associated with comorbidities or disability-related characteristics. In this study, we aimed to determine the patient and health-system level factors associated with all-cause and unplanned hospital readmission within 90 days after acute stroke or transient ischemic attack (TIA) in Australia. Methods- We used person-level linkages between data from the Australian Stroke Clinical Registry (2009-2013), hospital admissions data and national death registrations from 4 Australian states. Time to first readmission (all-cause or unplanned) for discharged patients was examined within 30, 90, and 365 days, using competing risks regression to account for deaths postdischarge. Covariates included age, stroke severity (ability to walk on admission), stroke type, admissions before stroke/TIA and the Charlson Comorbidity Index (derived from International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, [Australian modified] coded hospital data in the preceding 5 years). Results- Among the 13 594 patients discharged following stroke/TIA (45% female; 65% ischemic stroke; 11% intracerebral hemorrhage; 4% undetermined stroke; and 20% TIA), 25% had an all-cause readmission and 15% had an unplanned readmission within 90 days. In multivariable analyses, the factors independently associated with a greater risk of unplanned readmission within 90 days were being female (subhazard ratio, 1.13 [95% CI, 1.03-1.24]), greater Charlson Comorbidity Index scores (subhazard ratio, 1.11 [95% CI, 1.09-1.12]) and having an admission ≤90 days before the index event (subhazard ratio, 1.85 [95% CI, 1.59-2.15]). Compared with being discharged to rehabilitation or aged care, those who were discharged directly home were more likely to have an unplanned readmission within 90 days (subhazard ratio, 1.44 [95% CI, 1.33-1.55]). These factors were similar for readmissions within 30 and 365 days. Conclusions- Apart from comorbidities and patient-level characteristics, readmissions after stroke/TIA were associated with discharge destination. Greater support for transition to home after stroke/TIA may be needed to reduce unplanned readmissions.

Poly-Arginine Peptide-18 (R18) Reduces Brain Injury and Improves Functional Outcomes in a Nonhuman Primate Stroke Model.

Poly-arginine peptide-18 (R18) is neuroprotective in different rodent middle cerebral artery occlusion (MCAO) stroke models. In this study, we examined whether R18 treatment could reduce ischemic brain injury and improve functional outcome in a nonhuman primate (NHP) stroke model. A stroke was induced in male cynomolgus macaques by MCAO distal to the orbitofrontal branch of the MCA through a right pterional craniotomy, using a 5-mm titanium aneurysm clip for 90 min. R18 (1000 nmol/kg) or saline vehicle was administered intravenously 60 min after the onset of MCAO. Magnetic resonance imaging (MRI; perfusion-weighted imaging, diffusion-weighted imaging, or T2-weighted imaging) of the brain was performed 15 min, 24 h, and 28 days post-MCAO, and neurological outcome was assessed using the NHP stroke scale (NHPSS). Experimental endpoint was 28 days post-MCAO, treatments were randomized, and all procedures were performed blinded to treatment status. R18 treatment reduced infarct lesion volume by up to 65.2% and 69.7% at 24 h and 28 days poststroke, respectively. Based on NHPSS scores, R18-treated animals displayed reduced functional deficits. This study confirms the effectiveness of R18 in reducing the severity of ischemic brain injury and improving functional outcomes after stroke in a NHP model, and provides further support for its clinical development as a stroke neuroprotective therapeutic.

Poly-arginine-18 peptides do not exacerbate bleeding, or improve functional outcomes following collagenase-induced intracerebral hemorrhage in the rat.

BACKGROUND: Cationic arginine-rich peptides (CARPs) have demonstrated neuroprotective and/or behavioural efficacy in ischemic and hemorrhagic stroke and traumatic brain injury models. Therefore, in this study we investigated the safety and neuroprotective efficacy of the CARPs poly-arginine-18 (R18; 18-mer of arginine) and its D-enantiomer R18D given in the acute bleeding phase in an intracerebral hemorrhage (ICH) model. METHODS: One hundred and fifty-eight male Sprague-Dawley rats received collagenase-induced ICH. Study 1 examined various doses of R18D (30, 100, 300, or 1000 nmol/kg) or R18 (100, 300, 1000 nmol/kg) administered intravenously 30 minutes post-collagenase injection on hemorrhage volume 24 hours after ICH. Study 2 examined R18D (single intravenous dose) or R18 (single intravenous dose, plus 6 daily intraperitoneal doses) at 300 or 1000 nmol/kg commencing 30 minutes post-collagenase injection on behavioural outcomes (Montoya staircase test, and horizontal ladder test) in the chronic post-ICH period. A histological assessment of tissue loss was assessed using a Nissl stain at 28 days after ICH. RESULTS: When administered during ongoing bleeding, neither R18 or R18D exacerbated hematoma volume or worsened functional deficits. Lesion volume assessment at 28 days post-ICH was not reduced by the peptides; however, animals treated with the lower R18D 300 nmol/kg dose, but not with the higher 1000 nmol/kg dose, demonstrated a statistically increased lesion size compared to saline treated animals. CONCLUSION: Overall, both R18 and R18D appeared to be safe when administered during a period of ongoing bleeding following ICH. Neither peptide appears to have any statistically significant effect in reducing lesion volume or improving functional recovery after ICH. Additional studies are required to further assess dose efficacy and safety in pre-clinical ICH studies.

Poly-Arginine Peptides R18 and R18D Improve Functional Outcomes After Endothelin-1-Induced Stroke in the Sprague Dawley Rat.

We have previously demonstrated that R18 and its d-enantiomer, R18D, are neuroprotective at 24 hours following intraluminal filament occlusion of the middle cerebral artery (MCAO) in the rat. This study examined R18 and R18D effectiveness in improving functional outcomes at up to 56 days poststroke following endothelin-1-induced MCAO. Peptides were administered intravenously at doses of 100, 300, or 1000 nmol/kg, 60 minutes after MCAO. Functional recovery poststroke was assessed using multiple forelimb placing tests and horizontal ladder test, and NA-1 (TAT-NR2B9c), a neuroprotective currently in phase 3 clinical stroke trials, was used as a benchmark. The study demonstrated that R18 (300 and 1000 nmol/kg) was the most effective peptide in improving functional outcomes, followed by R18D (300 and 1000 nmol/kg), and NA-1 (300 and 100 nmol/kg). Furthermore, R18 at doses of 300 and 1000 nmol/kg was the most effective agent in restoring pre-stroke body weight, while R18 and R18D at doses of 300 and 1000 nmol/kg, but not NA-1 also significantly reduced the number of animals requiring hand feeding 48 hours after stroke. This study confirms that R18 and R18D are effective in improving long-term functional outcomes after stroke, and suggests that R18 may be more effective than NA-1.

Outcomes for Patients With In-Hospital Stroke: A Multicenter Study From the Australian Stroke Clinical Registry (AuSCR).

BACKGROUND: The quality of care and outcomes for people who experience stroke whilst in hospital for another condition has not been previously studied in Australia. AIMS: To explore differences in long-term outcomes among patients with in-hospital events treated in stroke units (SUs) compared to those managed in other hospital wards. METHODS: Forty-five hospitals participating in the Australian Stroke Clinical Registry between January 2010 and December 2014 contributed data. Survival of all patients with in-hospital stroke to 180 days after stroke and health-related quality of life, using EQ-5D-3L among 73% eligible, were compared using multilevel, multivariable regression models. Models were adjusted for age, sex, index of relative socioeconomic disadvantage, ability to walk, stroke type, transfer from another hospital, and history of stroke. RESULTS: Among 20,786 stroke events, 1182 (5.1%) occurred in-hospital (median age 77 years, 49% male). Patients with in-hospital stroke treated in SUs died less often within 30 days (Hazard Ratio 0.56; 95% CI 0.39-0.81) than those not admitted to SUs. Survivors reported similar health-related quality of life between 90 and 180 days compared to those treated in other wards (coefficient = 0.01, 95% CI -0.06-0.09, P = .78). Patients managed in SUs more often received recommended management (e.g. swallowing screening). CONCLUSION: The benefits of SU care may extend to patients experiencing in-hospital stroke. Validation, including accounting for potential residual confounding factors, is required.

Minocycline for acute stroke treatment: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: Various randomized-controlled clinical trials (RCTs) have investigated the neuroprotective role of minocycline in acute ischemic stroke (AIS) or acute intracerebral hemorrhage (ICH) patients. We sought to consolidate and investigate the efficacy and safety of minocycline in patients with acute stroke. METHODS: Literature search spanned through November 30, 2017 across major databases to identify all RCTs that reported following efficacy outcomes among acute stroke patients treated with minocycline vs. placebo: National Institute of Health Stroke Scale (NIHSS), Barthel Index (BI), and modified Rankin Scale (mRS) scores. Additional safety, neuroimaging and biochemical endpoints were extracted. We pooled mean differences (MD) and risk ratios (RR) from RCTs using random-effects models. RESULTS: We identified 7 RCTs comprising a total of 426 patients. Of these, additional unpublished data was obtained on contacting corresponding authors of 5 RCTs. In pooled analysis, minocycline demonstrated a favorable trend towards 3-month functional independence (mRS-scores of 0-2) (RR = 1.31; 95% CI 0.98-1.74, p = 0.06) and 3-month BI (MD = 6.92; 95% CI - 0.92, 14.75; p = 0.08). In AIS subgroup, minocycline was associated with higher rates of 3-month mRS-scores of 0-2 (RR = 1.59; 95% CI 1.19-2.12, p = 0.002; I2 = 58%) and 3-month BI (MD = 12.37; 95% CI 5.60, 19.14, p = 0.0003; I2 = 47%), whereas reduced the 3-month NIHSS (MD - 2.84; 95% CI - 5.55, - 0.13; p = 0.04; I2 = 86%). Minocycline administration was not associated with an increased risk of mortality, recurrent stroke, myocardial infarction and hemorrhagic conversion. CONCLUSIONS: Although data is limited, minocycline demonstrated efficacy and seems a promising neuroprotective agent in acute stroke patients, especially in AIS subgroup. Further RCTs are needed to evaluate the efficacy and safety of minocycline among ICH patients.

Comparison of neuroprotective efficacy of poly-arginine R18 and R18D (D-enantiomer) peptides following permanent middle cerebral artery occlusion in the Wistar rat and in vitro toxicity studies.

We have previously demonstrated that arginine-rich and poly-arginine peptides possess potent neuroprotective properties, with poly-arginine peptide R18 identified as being highly effective at reducing infarct volume following middle cerebral artery occlusion (MCAO) in the Sprague Dawley rat. Since peptides synthesised using D-isoform amino acids have greater stability than L-isoform peptides due to increased resistance to proteolytic degradation, they represent potentially more effective peptide therapeutics. Therefore we compared the neuroprotective efficacy of R18 and its D-enantiomer R18D following permanent MCAO in the Wistar rat. Furthermore, as increased peptide stability may also increase peptide toxicity, we examined the effects of R18 and R18D on cultured cortical neurons, astrocytes, brain endothelial cells (bEND.3), and embryonic kidney cells (HEK293) following a 10-minute or 24-hour peptide exposure duration. The in vivo studies demonstrated that R18D resulted in a greater reduction in mean infarct volume compared to R18 (33%, p = 0.004 vs 12%, p = 0.27) after intravenous administration at 300 nmol/kg 30 minutes after MCAO. Both R18D and R18 reduced cerebral hemisphere swelling to a comparable degree (27%, p = 0.03 and 30%, p = 0.02), and improved neurological assessment scores (1.5, p = 0.02 and 2, p = 0.058 vs 3 for vehicle). No abnormal histological findings specific to peptide treatments were observed in hematoxylin and eosin stained sections of kidney, liver, spleen, lung and heart. In vitro studies demonstrated that R18 and R18D were most toxic to neurons, followed by astrocytes, HEK293 and bEND.3 cells, but only at high concentrations and/or following 24-hour exposure. These findings further highlight the neuroprotective properties of poly-arginine peptides, and indicate that R18D at the dose examined is more potent than R18 in Wistar rats, and justify continued investigation of the R18 peptide as a novel neuroprotective agent for stroke.

Delayed 2-h post-stroke administration of R18 and NA-1 (TAT-NR2B9c) peptides after permanent and/or transient middle cerebral artery occlusion in the rat.

Following positive results with the poly-arginine peptide R18 when administered intravenously 30 or 60min after permanent and/or transient middle cerebral artery occlusion (MCAO; 90min) in the rat, we examined the effectiveness of the peptide when administered 2h after MCAO. R18 was administered intravenously (1000nmol/kg via jugular vein) after permanent MCAO or a transient 3-h MCAO or when administered intra-arterially (100nmol/kg via internal carotid artery) immediately after reperfusion following a transient 2-h MCAO. In the transient MCAO studies, the neuroprotective NA-1 peptide was used as a positive control. Infarct volume, cerebral edema and functional outcomes were measured 24h after MCAO. Following permanent or transient MCAO, neither R18 nor NA-1 significantly reduced infarct volume. However, following permanent MCAO, R18 appeared to reduce cerebral edema (p=0.006), whereas following a transient 3-h MCAO, R18 improved the time to remove adhesive tape (p=0.04) without significantly affecting cerebral edema. There was also a trend (p=0.07) towards improved rota-rod performance with R18 in both permanent and transient 3-h MCAO. Following a transient 2-h MCAO, R18 had no significant effects on cerebral edema or neurological score but did lessen the extent of weight loss. Overall, while R18 had no effect on infarct volume, the peptide reduced cerebral edema after permanent MCAO, and improved some functional outcomes after transient MCAO.