Endogenous SOD2 (Superoxide Dismutase) Regulates Platelet-Dependent Thrombin Generation and Thrombosis During Aging.

BACKGROUND: Reactive oxygen species (ROS) contribute to platelet hyperactivation during aging. Several oxidative pathways and antioxidant enzymes have been implicated; however, their mechanistic contributions during aging remain elusive. We hypothesized that mitochondria are an important source of platelet ROS and that mitochondrial SOD2 (superoxide dismutase) protects against mitochondrial ROS-driven platelet activation and thrombosis during aging. METHODS: We studied littermates of platelet-specific SOD2-knockout (SOD2fl/flPf4Cre, pSOD2-KO) and control (SOD2fl/fl) mice at young (4-5 months) or old (18-20 months) ages. We examined agonist-induced platelet activation, platelet-dependent thrombin generation potential, and susceptibility to in vivo thrombosis. RESULTS: Platelet αIIbß3 activation, aggregation, and adhesion were increased to similar extents in aged mice of both genotypes compared with young mice. In contrast, the age-dependent increases in mitochondrial and total cellular ROS, calcium elevation, and phosphatidylserine exposure were augmented in platelets from pSOD2-KO mice compared with control mice. Aged pSOD2-KO mice showed increased platelet-dependent thrombin generation compared with aged control mice. In vivo, aged pSOD2-KO mice exhibited enhanced susceptibility to carotid artery and pulmonary thrombosis compared to aged control mice. Adoptive transfer of platelets from aged pSOD2-KO but not aged control mice increased thrombotic susceptibility in aged host mice, suggesting a prothrombotic effect of platelet pSOD2 deficiency. Treatment with avasopasem manganese (GC4419), a SOD mimetic, decreased platelet mitochondrial pro-oxidants, cellular ROS levels, and inhibited procoagulant platelet formation and arterial thrombosis in aged mice. CONCLUSIONS: Platelet mitochondrial ROS contributes to age-related thrombosis and endogenous SOD2 protects from platelet-dependent thrombin generation and thrombosis during aging.

Vasopressin Initiation as a Second-Line VasoPressor in Early Septic Shock (VISPSS).

BACKGROUND: Vasopressin is recommended as a second-line vasoactive agent for the management of septic shock; however, a paucity of data to guide its optimal use remains. The aim was to evaluate the effect of time-to vasopressin initiation and norepinephrine (NE) dose at vasopressin initiation on clinical outcomes in patients presenting with septic shock. METHODS: This was a multi-centered, retrospective, observational study conducted in patients with septic shock. Patients were divided into 2 groups: patients initiated on vasopressin when NE-equivalent dose (NEE) < 0.25 mcg/kg/min or ≥ 0.25 mcg/kg/min. The primary outcome was time-to-vasopressor discontinuation (hours). Secondary outcomes included 28-day in-hospital mortality, intensive care unit (ICU) length of stay (LOS), fluid balance after 72 hours, and the change in NEE at 12 hours. RESULTS: A total of 302 patients were included in this study. After propensity-score matching, 73 patients in each group were identified for analysis. There was no significant difference in the time-to-vasopressor discontinuation (hours) between the groups (88.8 [55-187.5] vs 86.7 [47-172]); p = 0.7815). Fluid balance (mL) at 72 hours was significantly lower when vasopressin was initiated at NEE < 0.25 mcg/kg/min (1769 [71-7287] vs 5762 [1463-8813]; p = 0.0077). A multivariable linear regression showed shorter time to shock resolution with earlier vasopressin initiation, defined as within 4 hours (p < 0.05). CONCLUSION: In this propensity-score matched cohort, vasopressin initiation at NEE < 0.25 mcg/kg/min was not associated with shorter vasopressor duration. There was a lower fluid balance at 72 hours when vasopressin was initiated at lower NE doses.

Quantitative MRI Evaluation of Ferritin Overexpression in Non-Small-Cell Lung Cancer.

Cancer cells frequently present elevated intracellular iron levels, which are thought to facilitate an enhanced proliferative capacity. Targeting iron metabolism within cancer cells presents an avenue to enhance therapeutic responses, necessitating the use of non-invasive models to modulate iron manipulation to predict responses. Moreover, the ubiquitous nature of iron necessitates the development of unique, non-invasive markers of metabolic disruptions to develop more personalized approaches and enhance the clinical utility of these approaches. Ferritin, an iron storage enzyme that is often upregulated as a response to iron accumulation, plays a central role in iron metabolism and has been frequently associated with unfavorable clinical outcomes in cancer. Herein, we demonstrate the successful utility, validation, and functionality of a doxycycline-inducible ferritin heavy chain (FtH) overexpression model in H1299T non-small-cell lung cancer (NSCLC) cells. Treatment with doxycycline increased the protein expression of FtH with a corresponding decrease in labile iron in vitro and in vivo, as determined by calcein-AM staining and EPR, respectively. Moreover, a subsequent increase in TfR expression was observed. Furthermore, T2* MR mapping effectively detected FtH expression in our in vivo model. These results demonstrate that T2* relaxation times can be used to monitor changes in FtH expression in tumors with bidirectional correlations depending on the model system. Overall, this study describes the development of an FtH overexpression NSCLC model and its correlation with T2* mapping for potential use in patients to interrogate iron metabolic alterations and predict clinical outcomes.

Abrupt Discontinuation Versus Taper of Hydrocortisone in Patients With Septic Shock.

BACKGROUND: Although not mentioned in the most recent guidelines, the 2016 Surviving Sepsis Campaign guidelines recommend to taper corticosteroids once vasopressors are no longer needed; however, at the time of publication, there were no studies comparing taper versus abrupt discontinuation of corticosteroids. OBJECTIVES: The purpose of this study was to further evaluate the impact of abrupt versus taper discontinuation of corticosteroids in septic shock. METHODS: This was a retrospective cohort study that included patients who received an initial dose of 200 to 300 mg of hydrocortisone for septic shock. Participants were then divided into "abrupt" and "taper" groups. The primary outcome assessed was hemodynamic instability during taper or within 72 hours of the last corticosteroid dose. Secondary outcomes included intensive care unit (ICU) and hospital length of stay, incidence of hyperglycemia or hypernatremia, and in-hospital mortality. RESULTS: The primary outcome of reinitiation of vasopressor therapy occurred in a larger proportion of patients in the taper group compared with the abrupt group (21.9% vs 10.7%). The ICU length of stay (7.6 days abrupt vs 9 days taper) and hospital length of stay (14.9 vs 15.3 days) were similar between groups. There was a statistically significant increase in patients who experienced hyperglycemia within 24 hours of the last corticosteroid dose in the abrupt group. All other secondary outcomes were similar between groups. CONCLUSIONS: The abrupt discontinuation of hydrocortisone in the treatment of septic shock was associated with a nonstatistically significant 50% absolute reduction in the need for vasopressor reinitiation.

Impact of intravenous calcium with diltiazem for atrial fibrillation/flutter in the emergency department.

OBJECTIVE: The purpose of this study was to evaluate the effect of early intravenous (IV) calcium on systolic blood pressure (SBP) when administered with IV diltiazem in subjects with atrial fibrillation (AF) or flutter (AFL) with rapid ventricular response (RVR) in the Emergency Department (ED). METHODS: This was a multicenter, retrospective cohort study that evaluated adults admitted to the ED with documented AF or AFL, heart rate (HR) > 120 bpm, SBP 90 to 140 mmHg, and received treatment with IV diltiazem for rate control. The primary outcome was the change in SBP 60 min (+/- 30 min) after initial IV diltiazem administration. Secondary outcomes included time to initial rate control (HR < 100 bpm), time to sustained rate control (HR < 100 bpm for 3 h), change in HR, rates of hypotension, bradycardia, hypercalcemia, and line extravasation within 24 h of initial diltiazem administration. RESULTS: There were 198 subjects in the diltiazem monotherapy group and 56 subjects in the diltiazem with calcium group meeting the inclusion criteria. The primary outcome, median change in SBP 60 min after initial IV diltiazem administration, was similar between groups (-2 mmHg vs -1.5 mmHg; p = 0.642), but this difference was not statistically significant. All secondary outcomes were found to be similar between groups. Although not statistically significant, hypotension occurred more often in the diltiazem with calcium group (20.2% vs 32.1%; p = 0.060) while bradycardia occurred more often in the diltiazem monotherapy group (4.5% vs 0%; p = 0.213). In terms of achieving rate control, the administration of calcium with diltiazem did not significantly change the time to initial rate control (1.4 h vs 1.8 h; p = 0.141) or time to sustained rate control (7.9 h vs 7.7 h; p = 0.570) compared to diltiazem alone. CONCLUSIONS: In the setting of AF/AFL with RVR, administration of IV calcium with IV diltiazem did not show a significant impact on clinical or safety outcomes compared to IV diltiazem monotherapy.

Differential H2O2 Metabolism among Glioblastoma Subtypes Confers Variable Responses to Pharmacological Ascorbate Therapy Combined with Chemoradiation.

Glioblastoma (GBM), a highly lethal and aggressive central nervous system malignancy, presents a critical need for targeted therapeutic approaches to improve patient outcomes in conjunction with standard-of-care (SOC) treatment. Molecular subtyping based on genetic profiles and metabolic characteristics has advanced our understanding of GBM to better predict its evolution, mechanisms, and treatment regimens. Pharmacological ascorbate (P-AscH-) has emerged as a promising supplementary cancer therapy, leveraging its pro-oxidant properties to selectively kill malignant cells when combined with SOC. Given the clinical challenges posed by the heterogeneity and resistance of various GBM subtypes to conventional SOC, our study assessed the response of classical, mesenchymal, and proneural GBM to P-AscH-. P-AscH- (20 pmol/cell) combined with SOC (5 µM temozolomide and 4 Gy of radiation) enhanced clonogenic cell killing in classical and mesenchymal GBM subtypes, with limited effects in the proneural subtype. Similarly, following exposure to P-AscH- (20 pmol/cell), single-strand DNA damage significantly increased in classical and mesenchymal but not proneural GBM. Moreover, proneural GBM exhibited increased hydrogen peroxide removal rates, along with increased catalase and glutathione peroxidase activities compared to mesenchymal and classical GBM, demonstrating an altered H2O2 metabolism that potentially drives differential P-AscH- toxicity. Taken together, these data suggest that P-AscH- may hold promise as an approach to improve SOC responsiveness in mesenchymal GBMs that are known for their resistance to SOC.

Atracurium Versus Cisatracurium in the Treatment of Acute Respiratory Distress Syndrome.

Background: Neuromuscular blocking agents are one of the few medication classes that have demonstrated a clinical benefit in patients with severe acute respiratory distress syndrome (ARDS). However, most literature utilized cisatracurium, and utilization of atracurium is limited to 1 small study. Objective: The purpose of this study was to provide further evidence comparing the safety and efficacy of atracurium versus cisatracurium for the treatment of ARDS. Methods: This multicenter, retrospective, observational cohort noninferiority study was conducted at 3 hospitals within a tertiary health care system. We included subjects diagnosed with ARDS who received either atracurium or cisatracurium for at least 12 hours. The primary outcome measured the change in PaO2/FiO2 (P/F) ratio from baseline to 48 hours after initiation. Results: Baseline characteristics were similar between groups except for a higher median age and a higher proportion of subjects who were COVID-positive in the atracurium group. There were also some noted differences in the baseline P/F ratios. In a multivariable model adjusting for baseline characteristics, the change in the P/F ratio for atracurium was noninferior to cisatracurium at 24, 48, and 72 hours. A significant cost reduction, measured as cost per patient per day, was seen with the use of atracurium ($14.81-$25.16 vs $33.86-$41.91). Conclusion: Atracurium appears to be a safe and cheaper alternative agent in the management of ARDS.

Comparison of Early Versus Late Initiation of Hydrocortisone in Patients With Septic Shock in the ICU Setting.

BACKGROUND: Multiple publications demonstrate an association between time to initiation of corticosteroids and outcomes such as mortality and reversal of shock. However, the optimal time to initiate hydrocortisone remains unknown. OBJECTIVE: To evaluate the impact of early versus late initiation of hydrocortisone in septic shock patients. METHODS: A retrospective, multicentered, observational study was conducted. Adults admitted from July 1, 2014, to August 31, 2019, diagnosed with septic shock receiving vasopressors and low-dose hydrocortisone were evaluated. Participants were divided into the "early" group if hydrocortisone was initiated within 12 hours or "late" group if initiated after 12 hours of vasopressor initiation. The primary outcome was time to vasopressor discontinuation. Secondary outcomes included in-hospital mortality, intensive care unit (ICU) and hospital length of stay (LOS), vasopressor utilization, fluids administered, and need for renal replacement therapy. RESULTS: A total of 198 patients were identified for inclusion in this propensity score-weighted cohort: 99 in the early group and 99 in the late group. Early initiation was associated with shorter time to vasopressor discontinuation compared with late initiation (40.7 vs 60.6 hours; P = 0.0002). There was also a reduction in ICU LOS (3.6 vs 5.1 days; P = 0.0147) and hospital LOS (8.9 vs 10.9 days; P = 0.0220) seen in the early group. There was no difference in mortality between groups. CONCLUSION AND RELEVANCE: In this propensity-matched cohort, administration of hydrocortisone within 12 hours from the onset of septic shock was associated with improved time to vasopressor discontinuation and reduced ICU and hospital LOS.

Polyoxometalate Nanoparticles as a Potential Glioblastoma Therapeutic via Lipid-Mediated Cell Death.

Polyoxometalate nanoparticles (POMs) are a class of compounds made up of multiple transition metals linked together using oxygen atoms. POMs commonly include group 6 transition metals, with two of the most common forms using molybdenum and tungsten. POMs are suggested to exhibit antimicrobial effects. In this study, we developed two POM preparations to study anti-cancer activity. We found that Mo-POM (NH4)Mo7O24) and W-POM (H3PW12O40) have anti-cancer effects on glioblastoma cells. Both POMs induced morphological changes marked by membrane swelling and the presence of multinucleated cells that may indicate apoptosis induction along with impaired cell division. We also observed significant increases in lipid oxidation events, suggesting that POMs are redox-active and can catalyze detrimental oxidation events in glioblastoma cells. Here, we present preliminary indications that molybdenum polyoxometalate nanoparticles may act like ferrous iron to catalyze the oxidation of phospholipids. These preliminary results suggest that Mo-POMs (NH4)Mo7O24) and W-POMs (H3PW12O40) may warrant further investigation into their utility as adjunct cancer therapies.

Use of fibrinolytics for the management of massive pulmonary embolism in a patient with a history of subdural hemorrhage.

INTRODUCTION: Management of massive pulmonary embolism in patients with hemodynamic instability encompasses the use of fibrinolytics. Use of fibrinolytic therapy is currently recommended in this patient population by ACCP, AHA, and EHA if treatment benefit outweighs the risk of bleeding. There is currently no data challenging or exploring the risk of using fibrinolytic therapy for the management of massive PE in patients with a history of intracranial hemorrhage. CASE PRESENTATION: A 38-year old female with suspected massive pulmonary embolism was admitted with a chief complaint of chest pain and right leg pain. Shortly after a confirmatory CT of bilateral PE, the patient had multiple cardiac arrests along with severe shock that led to a general agreement among the team to proceed with IV and then catheter-directed TPA as well as thrombectomy. Following fibrinolytic therapy, the patient was started on a heparin drip along with epinephrine for hemodynamic support. CT chest angiography showed the resolution of emboli following treatment with the fibrinolytic agent. CT of the head taken approximately 24 h post tPA initiation was used to rule out intracranial hemorrhage or other complications resulting from tPA administration. CONCLUSION: In patients with a history of intracranial hemorrhage, catheter guided fibrinolytic and thrombectomy may be effective treatment options of massive pulmonary embolism.

Utilization of Pharmacological Ascorbate to Enhance Hydrogen Peroxide-Mediated Radiosensitivity in Cancer Therapy.

Interest in the use of pharmacological ascorbate as a treatment for cancer has increased considerably since it was introduced by Cameron and Pauling in the 1970s. Recently, pharmacological ascorbate has been used in preclinical and early-phase clinical trials as a selective radiation sensitizer in cancer. The results of these studies are promising. This review summarizes data on pharmacological ascorbate (1) as a safe and efficacious adjuvant to cancer therapy; (2) as a selective radiosensitizer of cancer via a mechanism involving hydrogen peroxide; and (3) as a radioprotector in normal tissues. Additionally, we present new data demonstrating the ability of pharmacological ascorbate to enhance radiation-induced DNA damage in glioblastoma cells, facilitating cancer cell death. We propose that pharmacological ascorbate may be a general radiosensitizer in cancer therapy and simultaneously a radioprotector of normal tissue.

Impact of Potentially Unwarranted Intravenous Antibiotics Targeting Pulmonary Infections in Acute Decompensated Heart Failure.

BACKGROUND: Acute decompensated heart failure (ADHF) can present similarly to pulmonary infections. The additional volume and sodium received from intravenous antibiotics (IVAB) can be counterproductive, especially when strong evidence of infection is lacking. OBJECTIVE: The objective was to evaluate the impact of potentially unwarranted IVAB on clinical outcomes in patients with ADHF. METHODS: This multicenter, retrospective, cohort study evaluated adults admitted with ADHF, a chest radiograph within 24 hours, B-natriuretic peptide >100 pg/mL, and either received no IVAB or IVAB for at least 48 hours. Subjects with recent antibiotics, justification for antibiotics, or transferred to the intensive care unit (ICU) within 24 hours of admission were excluded. The primary outcome was hospital length of stay (LOS). Secondary outcomes included utilization of loop diuretics, administration of fluid and sodium, mortality, and 30-day readmissions. RESULTS: Out of 240 subjects included, 120 received IVAB. LOS was significantly longer in the IVAB group (5.12 days vs 3.73 days; P < .001). LOS remained significantly longer in the IVAB group in a propensity score matched cohort (5.26 days vs 3.70 days; P < .001). The IVAB group received more volume and sodium from intravenous fluids (P < .001). ICU admission greater than 24 hours after admission was higher with IVAB (20% vs 7.5%; P = .049). No significant differences in total loop diuretics, intubation rate, mortality, and 30-day readmissions were identified. CONCLUSION: ADHF patients who received potentially unwarranted IVAB had longer hospital LOS and were more likely to be admitted to the ICU after 24 hours of hospitalization.

Long-term outcome comparison for standard fractionation (>59 Gy) versus hyperfractionated (>45 Gy) radiotherapy plus concurrent chemotherapy for limited-stage small-cell lung cancer.

BACKGROUND: Concurrent chemoradiotherapy (CCRT) is commonly employed in limited-stage small-cell lung cancer (LS-SCLC); however, the optimal radiotherapy regimen is still unknown. This 3-institution analysis compares long-term disease control and survival outcomes for once- (QD) versus twice-daily (BID) radiotherapy at contemporary doses. METHODS AND MATERIALS: Data were collected for LS-SCLC patients treated with platinum-based CCRT and planned RT doses of >5940 cGy at >180 cGy QD or >4500 cGy at 150 cGy BID. Comparative outcome analyses were performed for treatment groups. RESULTS: From 2005 through 2014, 132 patients met inclusion criteria for analysis (80 QD, 52 BID). Treatment groups were well-balanced, excepting higher rate of advanced mediastinal staging, longer interval from biopsy to treatment initiation, and lower rate of prophylactic cranial irradiation for the QD group, as well as institutional practice variation. At median survivor follow-up of 33.5 months (range, 4.6-105.8), 80 patients experienced disease failure (44 QD, 36 BID), and 106 died (62 QD, 44 BID). No differences in disease control or survival were demonstrated between treatment groups. CONCLUSION: The present analysis did not detect a difference in disease control or survival outcomes for contemporary dose QD versus BID CCRT in LS-SCLC.

Comparison of Fluoroquinolone Versus Non-Fluoroquinolone Therapy for Inpatient Treatment of Chronic Obstructive Pulmonary Disease Exacerbations.

Background: While antimicrobial use in the treatment of acute exacerbations of chronic obstructive pulmonary disease (COPD) is reserved for more severe cases, the current evidence available comparing fluoroquinolones (FQs) to other classes in the inpatient setting are lacking. Objective: To compare the effectiveness of FQ therapy compared with non-FQs (NFQs) during acute COPD exacerbations in hospitalized patients. Methods: In this single-centered institutional review board-approved retrospective chart review, participants were included if they were at least 18 years of age and hospitalized for an acute exacerbation of COPD. Patients were stratified into FQ or NFQ groups based on the initial antimicrobial regimen administered. The primary outcome was the clinical resolution rate after antimicrobial therapy. Secondary outcomes included length of hospital stay, duration of antimicrobial therapy, 30-day readmission rates, and Clostridioides difficile infection rates. Results: A total of 375 patients were included (FQ = 201; NFQ = 174). The NFQ group had a higher rate of clinical resolution (84.5% vs 76.1%, P = .0435). In a multivariable regression analysis, the association between NFQ therapy and higher rates of clinical resolution remained significant (odds ratio = 2.31; 95% confidence interval = 1.3-4.10; P = .0043). The FQ group had a shorter length of stay (4 vs 5 days; P = .0022) and shorter inpatient antibiotic duration (4 vs 5 days; P = .0200). Rates of Clostridioides difficile infection and readmission were similar between groups. Conclusions: NFQ therapy may provide a higher rate of clinical resolution while avoiding exposure to FQ therapy and known adverse effects associated with FQ use.

Comparison of Oral and Intravenous Tranexamic Acid for Prevention of Perioperative Blood Loss in Total Knee and Total Hip Arthroplasty.

BACKGROUND: Tranexamic acid (TA) is an antifibrinolytic agent that prevents perioperative blood loss in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). This benefit has been established with the intravenous (IV) dosage form, but there is limited evidence evaluating oral TA in this setting. OBJECTIVE: To compare the effect of oral versus IV TA on perioperative blood loss in those undergoing TKA or THA. METHODS: In this single-centered retrospective chart review, participants at least 18 years of age who received IV or oral TA from a single surgeon who performed their THA or TKA were included. The primary outcome evaluated hemoglobin (Hgb) reduction. Power analysis determined that 165 participants were required in each group to achieve 80% power, with a noninferiority margin of 0.3 mg/dL. RESULTS: Both study groups included 165 participants. Oral TA was noninferior to IV TA (Hgb difference = -0.12 g/dL [95% CI = -0.28 to 0.05; P = 0.0250]). A subgroup analysis of THA and TKA revealed that oral TA was noninferior to IV TA in THA (Hgb difference = 0.24 g/dL [95% CI = -0.17 to 0.5]), but oral TA failed to meet the noninferiority margin in the TKA subgroup (Hgb difference = -0.20 [95% CI = -0.38 to -0.02]). CONCLUSION: This study provides evidence that oral TA is a clinically effective and cost-efficient alternative to IV TA in the setting of THA and TKA.

Exploratory Analysis of Image-Guided Ionizing Radiation Delivery to Induce Long-Term Iron Accumulation and Ferritin Expression in a Lung Injury Model: Preliminary Results.

BACKGROUND: Radiation therapy (RT) is an integral and commonly used therapeutic modality for primary lung cancer. However, radiation-induced lung injury (RILI) limits the irradiation dose used in the lung and is a significant source of morbidity. Disruptions in iron metabolism have been linked to radiation injury, but the underlying mechanisms remain unclear. PURPOSE: To utilize a targeted radiation delivery approach to induce RILI for the development of a model system to study the role of radiation-induced iron accumulation in RILI. METHODS: This study utilizes a Small Animal Radiation Research Platform (SARRP) to target the right lung with a 20 Gy dose while minimizing the dose delivered to the left lung and adjacent heart. Long-term pulmonary function was performed using RespiRate-x64image analysis. Normal-appearing lung volumes were calculated using a cone beam CT (CBCT) image thresholding approach in 3D Slicer software. Quantification of iron accumulation was performed spectrophotometrically using a ferrozine-based assay as well as histologically using Prussian blue and via Western blotting for ferritin heavy chain expression. RESULTS: Mild fibrosis was seen histologically in the irradiated lung using hematoxylin and eosin-stained fixed tissue at 9 months, as well as using a scoring system from CBCT images, the Szapiel scoring system, and the highest fibrotic area metric. In contrast, no changes in breathing rate were observed, and median survival was not achieved up to 36 weeks following irradiation, consistent with mild lung fibrosis when only one lung was targeted. Our study provided preliminary evidence on increased iron content and ferritin heavy chain expression in the irradiated lung, thus warranting further investigation. CONCLUSIONS: A targeted lung irradiation model may be a useful approach for studying the long-term pathological effects associated with iron accumulation and RILI following ionizing radiation.

MRI Detection and Therapeutic Enhancement of Ferumoxytol Internalization in Glioblastoma Cells.

Recently, the FDA-approved iron oxide nanoparticle, ferumoxytol, has been found to enhance the efficacy of pharmacological ascorbate (AscH-) in treating glioblastoma, as AscH- reduces the Fe3+ sites in the nanoparticle core. Given the iron oxidation state specificity of T2* relaxation mapping, this study aims to investigate the ability of T2* relaxation to monitor the reduction of ferumoxytol by AscH- with respect to its in vitro therapeutic enhancement. This study employed an in vitro glioblastoma MRI model system to investigate the chemical interaction of ferumoxytol with T2* mapping. Lipofectamine was utilized to facilitate ferumoxytol internalization and assess intracellular versus extracellular chemistry. In vitro T2* mapping successfully detected an AscH--mediated reduction of ferumoxytol (25.6 ms versus 2.8 ms for FMX alone). The T2* relaxation technique identified the release of Fe2+ from ferumoxytol by AscH- in glioblastoma cells. However, the high iron content of ferumoxytol limited T2* ability to differentiate between the external and internal reduction of ferumoxytol by AscH- (ΔT2* = +839% for external FMX and +1112% for internal FMX reduction). Notably, the internalization of ferumoxytol significantly enhances its ability to promote AscH- toxicity (dose enhancement ratio for extracellular FMX = 1.16 versus 1.54 for intracellular FMX). These data provide valuable insights into the MR-based nanotheranostic application of ferumoxytol and AscH- therapy for glioblastoma management. Future developmental efforts, such as FMX surface modifications, may be warranted to enhance this approach further.

Auranofin Inhibition of Thioredoxin Reductase Sensitizes Lung Neuroendocrine Tumor Cells (NETs) and Small Cell Lung Cancer (SCLC) Cells to Sorafenib as well as Inhibiting SCLC Xenograft Growth.

Thioredoxin Reductase (TrxR) is a key enzyme in hydroperoxide detoxification through peroxiredoxin enzymes and in thiol-mediated redox regulation of cell signaling. Because cancer cells produce increased steady-state levels of reactive oxygen species (ROS; i.e., superoxide and hydrogen peroxide), TrxR is currently being targeted in clinical trials using the anti-rheumatic drug, auranofin (AF). AF treatment decreased TrxR activity and clonogenic survival in small cell lung cancer (SCLC) cell lines (DMS273 and DMS53) as well as the lung atypical (neuroendocrine tumor) NET cell line H727. AF treatment also significantly sensitized DMS273 and H727 cell lines in vitro to sorafenib, a multi-kinase inhibitor that was shown to decrease intracellular glutathione. The pharmacokinetic and pharmacodynamic properties of AF treatment in a mouse SCLC xenograft model was examined to maximize inhibition of TrxR activity without causing toxicity. AF was administered intraperitoneally at 2 mg/kg or 4 mg/kg (IP) once (QD) or twice daily (BID) for 1 to 5 days in mice with DMS273 xenografts. Plasma levels of AF were 10-20 µM (determined by mass spectrometry of gold) and the optimal inhibition of TrxR (50 %) was obtained at 4 mg/kg once daily, with no effect on glutathione peroxidase 1 activity. When this daily AF treatment was extended for 14 days a significant prolongation of median survival from 19 to 23 days (p=0.04, N=30 controls, 28 AF) was observed without causing changes in animal bodyweight, CBCs, bone marrow toxicity, blood urea nitrogen, or creatinine. These results show that AF is an effective inhibitor of TrxR both in vitro and in vivo in SCLC, capable of sensitizing NETs and SCLC to sorafenib, and supports the hypothesis that AF could be used as an adjuvant therapy with agents known to induce disruptions in thiol metabolism to enhance therapeutic efficacy.

The antioxidant and anti-inflammatory activities of avasopasem manganese in age-associated, cisplatin-induced renal injury.

PURPOSE: Cisplatin contributes to acute kidney injury (AKI) and chronic kidney disease (CKD) that occurs with greater frequency and severity in older patients. Age-associated cisplatin sensitivity in human fibroblasts involves increased mitochondrial superoxide produced by older donor cells. EXPERIMENTAL DESIGN: Young and old C57BL/6 J murine models of cisplatin-induced AKI and CKD were treated with the SOD mimetic avasopasem manganese to investigate the potential antioxidant and anti-inflammatory effects. Adverse event reporting from a phase 2 and a phase 3 randomized clinical trial (NCT02508389 and NCT03689712) conducted in patients treated with cisplatin and AVA was determined to have established the incidence and severity of AKI. RESULTS: Cisplatin-induced AKI and CKD occurred in all mice, however, was more pronounced in older mice. AVA reduced cisplatin-induced mortality, AKI, and CKD, in older animals. AVA also alleviated cisplatin-induced alterations in mitochondrial electron transport chain (ETC) complex activities and NADPH Oxidase 4 (NOX4) and inhibited the increased levels of the inflammation markers, TNFα, IL1, ICAM-1, and VCAM-1. Analysis of age-stratified subjects treated with cisplatin from clinical trials (NCT02508389, NCT03689712) also supported that the incidence of AKI increased with age and AVA reduced age-associated therapy-induced adverse events (AE), including hypomagnesemia, increased creatinine, and AKI. CONCLUSIONS: Older mice and humans are more susceptible to cisplatin-induced kidney injury, and treatment with AVA mitigates age-associated damage. Mitochondrial ETC and NOX4 activities represent sources of superoxide production contributing to cisplatin-induced kidney injury, and pro-inflammatory cytokine production and endothelial dysfunction may also be increased by superoxide formation.

Superoxide Dismutase Mimetic Avasopasem Manganese Enhances Radiation Therapy Effectiveness in Soft Tissue Sarcomas and Accelerates Wound Healing.

Soft tissue sarcomas (STSs) are mesenchymal malignant lesions that develop in soft tissues. Despite current treatments, including radiation therapy (RT) and surgery, STSs can be associated with poor patient outcomes and metastatic recurrences. Neoadjuvant radiation therapy (nRT), while effective, is often accompanied by severe postoperative wound healing complications due to damage to the surrounding normal tissues. Thus, there is a need to develop therapeutic approaches to reduce nRT toxicities. Avasopasem manganese (AVA) is a selective superoxide dismutase mimetic that protects against IR-induced oral mucositis and lung fibrosis. We tested the efficacy of AVA in enhancing RT in STSs and in promoting wound healing. Using colony formation assays and alkaline comet assays, we report that AVA selectively enhanced the STS (liposarcoma, fibrosarcoma, leiomyosarcoma, and MPNST) cellular response to radiation compared to normal dermal fibroblasts (NDFs). AVA is believed to selectively enhance radiation therapy by targeting differential hydrogen peroxide clearance in tumor cells compared to non-malignant cells. STS cells demonstrated increased catalase protein levels and activity compared to normal fibroblasts. Additionally, NDFs showed significantly higher levels of GPx1 activity compared to STSs. The depletion of glutathione using buthionine sulfoximine (BSO) sensitized the NDF cells to AVA, suggesting that GPx1 may, in part, facilitate the selective toxicity of AVA. Finally, AVA significantly accelerated wound closure in a murine model of wound healing post RT. Our data suggest that AVA may be a promising combination strategy for nRT therapy in STSs.