A novel nanoparticle delivery system for targeted therapy of noise-induced hearing loss

Hearing loss is the most prevalent sensory disability worldwide and may be caused by age, drugs or exposure to excessive noise. We have previously developed a minimally-invasive nanohydrogel drug delivery system that successfully delivers nanoparticles into the inner ear. We have substantially extended this technique by functionalizing the nanoparticles and introducing a targeting peptide which recognizes prestin, a transmembrane electromotile protein uniquely expressed in outer hair cells (OHCs) of the inner ear. We demonstrate the successful delivery of molecules and plasmids specifically to OHCs. When compared to untargeted nanoparticles, the delivery of a c-Jun N-terminal kinase (JNK) inhibitor, D-JNKi-1, to OHCs by targeted nanoparticles improved protection from noise induced hearing loss (NIHL). This is the first demonstration of a protection from NIHL using a novel safe and controllable delivery system which is minimally-invasive to the inner ear and, as such, is an extremely appealing technique for use in many clinical applications.

Encephaloduroarteriosynangiosis Averts Stroke in Atherosclerotic Patients With Border-Zone Infarct: Post Hoc Analysis From a Performance Criterion Phase II Trial

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is one of the leading causes of stroke worldwide. Patients with ICAD who initially present with ischemia in border-zone areas and undergo intensive medical management (IMM) have the highest recurrence rates (37% at 1 yr) because of association with hemodynamic failure and poor collaterals.

OBJECTIVE

To evaluate the effect of encephaloduroarteriosynagiosis (EDAS) on stroke recurrence in patients with ICAD and border-zone stroke (BDZS) at presentation.

METHODS

A phase II clinical trial of EDAS revascularization for symptomatic ICAD failing medical management (EDAS Revascularization for Symptomatic Intracranial Atherosclerosis Steno-occlusive [ERSIAS]) was recently concluded. We analyze the outcomes of the subgroup of patients with BDZS at presentation treated with EDAS vs the previously reported Stenting versus Aggressive Medical Management for Preventing Recurrent stroke in Intracranial Stenosis (SAMMPRIS) IMM subgroup with BDZS at presentation.

RESULTS

Of 52 patients included in the ERSIAS trial, 35 presented with strokes at baseline, and 28 had a BDZ pattern, including 15 (54%) with exclusive BDZS and 13 (46%) with mixed patterns (BDZ plus other distribution). Three of the 28 (10.7%) had recurrent strokes up to a median follow-up of 24 months. The rate of recurrent stroke in ICAD patients with BDZS at presentation after EDAS was significantly lower than the rate reported in the SAMMPRIS IMM subgroup with BDZS at presentation (10.7% vs 37% P = .004, 95% CI = 0.037-0.27).

CONCLUSION

ICAD patients with BDZS at presentation have lower rates of recurrent stroke after EDAS surgery than those reported with medical management in the SAMMPRIS trial. These results support further investigation of EDAS in a randomized clinical trial.

A Novel Nano-approach for Targeted Inner Ear Imaging

During the last decade, there have been major improvements in imaging modalities and the development of molecular imaging in general. However detailed inner ear imaging still provides very limited information to physicians. This is unsatisfactory as sensorineural hearing loss is the main cause of permanent hearing loss in adults and at least 134 genetic mutations that result in congenital hearing loss have been identified. We are still unable, in most cases where gross anatomical changes are not observed, to determine the exact cause of hearing loss at a cellular or molecular level in patients using non-invasive techniques. This limitation in inner ear diagnostic modalities is a major obstacle behind the delay in discovering treatments for many of the causes of sensorineural hearing loss. This paper initially investigated the use of targeted gold nanoparticles as contrast agents for inner ear imaging. These nanoparticles have many useful characteristics such as being easy to target and possessing minimal cytotoxicity. We were able to detect the nanoparticles diffusing in the hair cells using confocal microscopy. Regrettably, despite their many admirable characteristics, the gold nanoparticles were unable to significantly enhance CT imaging of the inner ear. Consequently, we investigated liposomal iodine as a potential solution for the unsatisfactory CT contrast obtained with the gold nanoparticles. Fortunately, significant enhancement of the micro-CT image was observed with either Lugol’s solution or liposomal iodine, with Lugol’s solution enabling fine inner ear structures to be detected.

The Development of a Nano-based Approach to Alleviate Cisplatin-Induced Ototoxicity

Cisplatin-induced hearing loss is experienced by a high percentage of patients with squamous cell carcinoma undergoing cisplatin chemotherapy. A novel nano-construct capable of sequestering extracellular cisplatin was developed to combat this problem. The nano-construct consisted of superparamagnetic iron oxide nanoparticles (SPIONs) entrapped within polymeric micelles, which were formed from a glutathione diethyl ester-conjugated amphiphilic diblock copolymer. The glutathione-micelles were analyzed at the cellular level and in an organotypic study for safety evaluation. All utilized methods indicated that the micelles do not cause cellular toxicity or organ damage. The micelles' ability to reduce cisplatin-induced cytotoxicity was then probed in an in vitro model. Cisplatin was pre-treated with the novel nano-construct before being added to growing cells. When compared to cells that were exposed to untreated cisplatin, cells in the pre-treated cisplatin group showed a significant increase in cell viability. This clearly demonstrates that the construct is able to protect the cells from cisplatin cytotoxicity and makes it highly likely that the novel nano-construct will be able to play a role in the protection of the inner ear from cisplatin-induced ototoxicity.

Abstract TP177: Comparison Of Baseline Serum Glucose Concentration Between Fast And Slow Progressor Phenotypes Of Anterior Circulation Large Vessel Occlusion Stroke

Introduction: The determinants of fast and slow progressor phenotypes of infarct growth in anterior circulation large vessel occlusion (ACLVO) remain poorly understood. Previous studies have shown a potential link between baseline serum glucose and acute infarct growth. We assessed whether presenting serum glucose is independently associated with fast or slow progression of infarct growth in ACLVO stroke.

Methods: Retrospective analysis of patients with acute stroke due to intracranial ICA or proximal MCA occlusion across two comprehensive stroke centers from 2014-2019. Baseline CTP or MRI were obtained within 24hours of stroke onset. Fast progressors (ischemic core > 70ml, 0-6 h) and slow progressors (</= 30ml, 6-24 h) were identified. Serum glucose levels were compared in two groups: fast vs. non-fast progressors (0-6 h), slow vs. non-slow progressors (6-24 h). Mann-Whitney test was used for univariate group comparisons. Pearson correlation tested the association between serum glucose and infarct growth rate (core volume / time of stroke onset to imaging).

Results: A total of 350 participants were included (n=178 imaged < 6 hours of stroke onset; n=172 imaged at 6-24 hours of stroke onset). Amongst early presenters, the median glucose was 127 mg/dL for fast progressors (n=32) versus 122 mg/dL in non-fast progressors (n=146), p=0.45. Amongst late presenters, the median glucose was 122 mg/dL for slow progressors versus 133 in non-slow progressors (p=0.085). The correlation between serum glucose concentration and infarct growth rate was 0.03 (p=0.57).

Conclusion: While a numerical trend suggesting lower glucose levels was observed in slow progressors, no significant correlation between hyperacute serum glucose and infarct growth rate was established.

Association of renal biomarkers with fast progressor phenotype and related outcomes in anterior circulation large vessel occlusion stroke

Background

Renal dysfunction is a known predictor of long-term functional dependency after anterior circulation large vessel occlusion (ACLVO) stroke. However, the impact of renal dysfunction on early infarct growth rate (IGR) has not been previously demonstrated. The objective of this study was to define the association of creatinine-based renal biomarkers with fast or slow progressor phenotypes and related clinical outcomes in ACLVO stroke.

Methods

This retrospective study examined patients with acute intracranial internal carotid artery or middle cerebral artery-M1 occlusions admitted between 2014 and 2019. Patients were included if they received baseline CT perfusion (CTP) or MRI on presentation within 24 h of estimated stroke onset. Infarct growth rate (IGR) was determined by ischemic core volume on CTP or MRI divided by time from stroke onset to imaging. IGR was used to stratify fast progressor (IGR ≥10 mL/h) and slow progressor (IGR < 10 mL/h) status. Renal dysfunction was assessed based on serum creatinine and estimated glomerular filtration rate (eGFR) on presenting laboratories. Logistic regression models, adjusted for significant covariates, identified independent associations between renal dysfunction biomarkers, progressor status, and clinical outcomes based on modified Rankin Scale (mRS) at 90 days.

Results

Among 230 patients with ACLVO, 29% were fast progressors, with median serum creatinine levels higher than slow progressors (1.1 vs. 0.9 mg/dL, p < 0.05) and lower median eGFR (66.2 vs. 69.0 mL/min/1.73m2, p < 0.05). Elevated creatinine (≥1.2 mg/dL) was independently associated with fast progressor status (adjusted OR 2.37, 95% CI 1.18-4.77), worse 90-day mRS (adjusted OR 1.88, 95% CI 1.01-3.51) and mortality (adjusted OR 2.57, 95% CI 1.14-5.79). Reduced eGFR (<60 mL/min/1.73m2) was independently associated with fast progressor status (adjusted OR 2.38, 95% CI 1.14-4.94), but not with 90-day mRS or mortality.

Conclusion

Serum creatinine-based biomarkers of renal dysfunction were associated with fast progressor phenotype of ACLVO stroke, and worse clinical outcomes, which may help identify such patients earlier during emergency evaluation for expedited access to EVT. Future prospective studies are warranted to confirm and test implementation of these findings.

The Clinical Utility of High-Resolution Vessel Wall Imaging in Screening for Meningovascular Neurosyphilis

Meningovascular neurosyphilis is a common cause of stroke in young adults, particularly when HIV co-infection is present. Contemporary screening for neurosyphilis relies on invasive testing. High resolution vessel wall imaging (HR-VW) is an emerging non-invasive tool to detect intracranial vessel wall inflammation. We report a case of multifocal acute cerebral infarctions from meningovascular neurosyphillis in which HR-VWI was instrumental in leading to the etiological diagnosis. A 32-year-old man with history of untreated HIV and polysubstance abuse presented with sudden onset vertigo. CT angiogram of the head and neck showed non-dominant left extracranial vertebral artery occlusion in the V1 segment, and multifocal areas of stenoses in V2 through V4 segments. Non-contrast brain MRI demonstrated multiple small acute infarcts in the left cerebellum, left brachium pontis, medulla and occipital lobe. Rapid plasma reagin was reactive. 3D whole-brain HR-VWI revealed concentric vessel wall contrast enhancement in the left V4 segment, suggestive of inflammation. This HR-VWI finding prompted further investigation with cerebrospinal fluid analysis that revealed reactive fluorescent treponemal antibody absorption test. The patient received high-dose intravenous Penicillin G, was restarted on highly active antiretroviral therapy, and remained neurologically stable to-date. With high spatial resolution and signal-to-noise ratio, HR-VWI allows for visualization of vessel wall inflammation in co-morbid HIV and neurosyphilis.