Cell survival after DNA damage in the comet assay.

The comet assay is widely used in basic research, genotoxicity testing, and human biomonitoring. However, interpretation of the comet assay data might benefit from a better understanding of the future fate of a cell with DNA damage. DNA damage is in principle repairable, or if extensive, can lead to cell death. Here, we have correlated the maximally induced DNA damage with three test substances in TK6 cells with the survival of the cells. For this, we selected hydrogen peroxide (H2O2) as an oxidizing agent, methyl methanesulfonate (MMS) as an alkylating agent and etoposide as a topoisomerase II inhibitor. We measured cell viability, cell proliferation, apoptosis, and micronucleus frequency on the following day, in the same cell culture, which had been analyzed in the comet assay. After treatment, a concentration dependent increase in DNA damage and in the percentage of non-vital and apoptotic cells was found for each substance. Values greater than 20-30% DNA in tail caused the death of more than 50% of the cells, with etoposide causing slightly more cell death than H2O2 or MMS. Despite that, cells seemed to repair of at least some DNA damage within few hours after substance removal. Overall, the reduction of DNA damage over time is due to both DNA repair and death of heavily damaged cells. We recommend that in experiments with induction of DNA damage of more than 20% DNA in tail, survival data for the cells are provided.

Evaluation of hydrogen peroxide-assisted endoscopic ultrasonography-guided necrosectomy in walled-off pancreatic necrosis: A single-center experience.

ABSTRACT: Hydrogen peroxide is a liquid that functions in mechanical removal of the necrotic tissue via the elimination of tissue debris.In this study, we aimed to evaluate the effectiveness of the use of hydrogen peroxide in necrosectomy treatment of walled-off pancreatic necrosis.Records of 24 patients who were diagnosed with pancreatic necrosis or walled-off pancreatic necrosis and underwent endoscopic necrosectomy (EN) were retrospectively assessed. Patients were divided into 2 groups; hydrogen peroxide used for treatment or not used, and these 2 groups were compared.A total of 24 patients underwent endoscopic intervention for walled-off pancreatic necrosis. Procedural success was comparable between the 2 groups. During the post-procedural follow-up, the duration of the hospital stay, recurrence, and complication rates were found to be similar in both groups. The mean number of the endoscopic interventions was significantly lower in the hydrogen peroxide group (4.2 ±â€Š1.4 vs 6.1 ±â€Š4.2; P = .01).The use of hydrogen peroxide for EN in walled-off pancreatic necrosis patients seems to have similar efficiency and safety. However, it can be said that the use of hydrogen peroxide could reduce the number of endoscopic procedures.

Hydrogen Peroxide 40% for the Treatment of Seborrheic Keratoses.

OBJECTIVE: Hydrogen peroxide 40% (HP40) was approved by the US Food and Drug Administration for topical treatment of seborrheic keratosis (SK) in December 2017. This article will review phase II and III clinical trials to assess the drug's efficacy, safety, and clinical application. DATA SOURCES: A systematic literature review was performed using the terms "Eskata AND seborrheic keratosis," and "hydrogen peroxide AND seborrheic keratosis" in the OVID MEDLINE, PubMed, Cochrane Library, EMBASE, and Web of Science databases. ClinicalTrials.gov was searched to identify ongoing or nonpublished studies. STUDY SELECTION AND DATA ABSTRACTION: Articles written in English between January 2000 and mid-June 2020 discussing phase II and phase III clinical trials were evaluated. DATA SYNTHESIS: In 2 phase III clinical trials, 4% and 8% of patients treated with HP40 had a Physician Lesion Assessment score of zero for all 4 SKs, respectively, compared with 0% in both vehicle groups at the primary end point of day 106 (P < 0.01; P < 0.0001). RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: HP40, although less effective, has a better safety profile than other treatment options. It should be especially considered for treatment of facial SKs, where it is most efficacious and where other treatment modalities, such as cryotherapy, are more challenging. CONCLUSIONS: HP40 is a new, safe alternative treatment for SKs, although it is expensive and only modestly effective, both of which somewhat limit its overall utility. HP40 is a promising topical alternative, particularly for cosmetically sensitive locations, such as the face.

The effect of chronic dosing and p53 status on the genotoxicity of pro-oxidant chemicals in vitro.

In this study, we have studied the cytotoxicity and genotoxic potency of 3 pro-oxidants; H2O2, menadione and KBrO3 in different dosing scenarios, namely acute (1-day dosing) and chronic (5-days). For this purpose, relative population doubling (RPD%) and mononucleated micronucleus (MN) test were used. TK6 cells and NH32 were employed in in vitro experiments. In the study, the total acute dose was divided into 5 days for each prooxidant chemicals by dose fractionation (1/5th per day) method. Acute dosing was compared to chronic dosing. The oxidative stress caused by the exposure of cells with pro-oxidant chemicals to the cells was determined by an optimized 2',7'-dichlorofluorescein diacetate (DCFHDA) test method. The antioxidant levels of the cell lines were altered with buthionine sulfoxide (BSO) and N-acetyl cysteine (NAC), and the effect of antioxidant capacity on the MN formation in the cells was observed with this method. In the case of H2O2 and menadione, fractional dosing has been observed to result in lower toxicity and lower genotoxicity. But in the case of KBrO3, unlike the other 2 pro-oxidants, higher MN induction was observed with fractionated doses. DCFHDA test clearly demonstrated ROS induction with H2O2 and menadione but not with KBrO3. Unexpectedly, DCFHDA test demonstrated that KBrO3 did not cause an increase ROS levels in both acute and chronic dosing, suggesting an alternative ROS induction mechanism. It was also observed that, treatment with BSO and NAC, caused increasing and decreasing of MN fold change respectively, allowing further ROS specific mechanisms to be explored. Hence, dose fractionation expectedly caused less MN, cytotoxicity and ROS formation with H2O2 and menadione exposure, but not with KBrO3. This implies a unique mechanism of action for KBrO3 induced genotoxicity. Chronic dosing in vitro may be a valuable approach allowing better understanding of how chemicals damage DNA and pose human hazards.

Hydrogen Peroxide Topical Solution, 45% for Common Warts: Phase 2 Efficacy and Safety Trial Results.

BACKGROUND: No FDA-approved prescription therapies are available for common warts. OBJECTIVE: We evaluated a proprietary hydrogen peroxide topical solution, 45% (w/w) (HP45) for treatment of common warts. METHODS: In the phase 2 randomized, double-blind, vehicle-controlled WART-203 trial (NCT03278028), eligible patients aged ≥8 years had 1–6 warts (1 target wart) on the trunk or extremities with a Physician’s Wart Assessment™ (PWA) grade ≥2 (range, 0 [clear] to 3 [wart 3–8 mm in diameter or length]). Patients self-administered HP45 or vehicle twice weekly for 8 weeks and were evaluated through 12 weeks posttreatment (week 20). Efficacy assessments included mean change in target wart PWA grade from baseline at week 8 (primary endpoint) and proportions of patients with target wart clearance. Safety assessments included treatment-emergent adverse events (TEAEs) and local skin reactions (LSRs). RESULTS: A total of 157 patients completed 8 weeks of treatment (HP45, n=79; vehicle, n=78); 151 patients completed the 20-week posttreatment evaluation (HP45, n=75; vehicle, n=76). A significantly greater reduction in mean target wart PWA grade from baseline at week 8 was achieved with HP45 (−0.87) vs vehicle (−0.17; P<0.0001) and maintained at week 20 (−1.00 vs −0.39; P=0.0004). The proportion of patients with target wart clearance at week 8 was significantly greater with HP45 (25.3%) vs vehicle (2.6%; P<0.0001) and remained significantly greater at week 20 (37.3% vs 11.8%; P=0.0002). Forty-seven patients reported 76 TEAEs; most were mild or moderate in severity. Most LSRs were mild and resolved by week 20. In pediatric patients (HP45, n=13; vehicle, n=6), greater reductions in mean target wart PWA grade from baseline were observed with HP45 vs vehicle at weeks 8 (−1.0 vs 0) and 20 (−1.2 vs −0.5). CONCLUSION: These findings support the efficacy and safety of HP45 for the treatment of common warts in patients ≥8 years of age. J Drugs Dermatol. 2020;19(10):969-976. doi:10.36849/JDD.2020.5054.

Biomarkers for the toxicity of sublethal concentrations of triclosan to the early life stages of carps.

Accumulation, contents of protein, non-enzymatic antioxidant glutathione (GSH and GSSG), lipid peroxidation product (melondialdehyde-MDA) and organic acids (fumarate, succinate, malate and citrate), and activities of neurological (acetylcholinesterase-AChE), detoxification (glutathione S-transferase-GST) and metabolic (lactate dehydrogenase-LDH, aspartate transaminase-AST and alanine transaminase-ALT) enzymes were recorded in the hatchlings of Cyprinus carpio, Ctenopharyngodon idella, Labeo rohita and Cirrhinus mrigala after 7 and 14 days exposure and 10 days post exposure (recovery period) to sublethal concentrations (0.005, 0.01, 0.02 and 0.05 mg/L) of triclosan, a highly toxic and persistent biocide used in personal care products. Accumulation was maximum between 7-14 days at 0.01 mg/L for C. carpio and L. rohita but at 0.005 mg/L for C. idella and C. mrigala. No triclosan was observed at 0.005 mg/L in C. carpio and C. mrigala after recovery. Significant decline in protein, glutathione and acetylcholinesterase but increase in glutathione S-transferase, lactate dehydrogenase, aspartate transaminase, alanine transaminase, melondialdehyde and organic acids over control during exposure continued till the end of recovery period. Integrated biomarker response (IBR) analysis depicted higher star plot area for glutathione and glutathione S-transferase during initial 7 days of exposure, thereafter, during 7-14 days of exposure and the recovery period, higher star plot area was observed for acetylcholinesterase, aspartate transaminase, alanine transaminase and organic acids. Higher star plot area was observed for protein in all the species throughout the study. The study shows that L. rohita is most sensitive and glutathione, acetylcholinesterase, aspartate transaminase and alanine transaminase are the biomarkers for the toxicity of sublethal concentrations of TCS.

Effect of different floatation solutions on E. tenella oocyst purification and optimization of centrifugation conditions for improved recovery of oocysts and sporocysts.

Saturated salt floatation method is widely used for coccidian oocyst purification. However, the repeated procedures and inefficient oocysts recovery rate are a continuous challenge. This study aimed to investigate the best suitable floatation solution, along with optimal centrifugation speed and time for Eimeria tenella (E. tenella) oocyst and sporocyst purification. Different floatation solutions i-e, saturated salt, Sheather's sugar and sodium hypochlorite (NaClO) at 20-60% concentrations were used to purify oocyst. It was found that about 96.99% oocysts (8609×g for 10 min) were recovered under these conditions without any effect on the viability of sporocysts. The recovery rate of oocysts using 50% NaClO (V/V) was significantly higher than 35% saturated salt flotation solution (P < 0.05). The optimal method for purification of oocysts based our experimentation was centrifugation at 8609×g for 3 min using 50% NaClO floatation solution, and the optimized centrifugation conditions for improved recovery of sporocysts (about 99.3%) were at 2152×g for 5 min. The present study provided a better method for the coccidian oocyst purification, which could be successfully adopted as a better alternative to existing techniques commonly used for investigations/research pertaining to coccidia.

Porphyrin-Loaded TyroSpheres for the Intracellular Delivery of Drugs and Photoinduced Oxidant Species.

In order to understand the intracellular delivery of drugs and to improve the cell killing efficiency of photosensitizers (PSs) used in photodynamic therapy (PDT), we prepared TyroSphere nanoparticles, which are triblock polymer [poly(ethylene glycol)-block-oligo(desaminotyrosyltyrosine octyl ester suberate)-block-poly(ethylene glycol)] aggregates, loaded with amphiphilic porphyrins with either positive (CisDiMPyP) or negative (TPPS2a) charges. Their physicochemical and photochemical properties were investigated, as well as the efficiency and mechanism of PDT death in a cervical cancer cell line (HeLa). The photophysical properties of both PSs were improved when loaded in the nanocarrier, with a decrease in aggregation as well as an increase in the yield of singlet oxygen generation. The physical and chemical stability of TyroSphere nanoparticles allows them to enter cells and to promote the slow intracellular delivery of part of the PSs. Confocal steady-state and lifetime-resolved fluorescence imaging microscopy data showed that the released PSs are free to target their natural intracellular targets, which are mitochondria and lysosomes for CisDiMPyP and TPPS2a, respectively. The photodynamic efficiency of cell killing was increased considerably compared with the free PSs (∼3×), but the mechanism of cell death was the same as that of the free PSs, which are acute necro-apoptosis for CisDiMPyP and autophagy malfunction for TPPS2a, reflecting the specific damage in mitochondria and lysosomes, respectively. We are confident that TyroSpheres provide a novel and efficient platform to administrate PDT photosensitizers, as well as other drugs with intracellular targets.

Intratumoral Hydrogen Peroxide With Radiation Therapy in Locally Advanced Breast Cancer: Results From a Phase 1 Clinical Trial.

PURPOSE: Hydrogen peroxide (H2O2) plays a vital role in normal cellular processes but at supraphysiological concentrations causes oxidative stress and cytotoxicity, a property that is potentially exploitable for the treatment of cancer in combination with radiation therapy (RT). We report the first phase 1 trial testing the safety and tolerability of intratumoral H2O2 + external beam RT as a novel combination in patients with breast cancer and exploratory plasma marker analyses investigating possible mechanisms of action. METHODS AND MATERIALS: Twelve patients with breast tumors ≥3 cm (surgically or medically inoperable) received intratumoral H2O2 with either 36 Gy in 6 twice-weekly fractions (n = 6) or 49.5 Gy in 18 daily fractions (n = 6) to the whole breast ± locoregional lymph nodes in a single-center, nonrandomized study. H2O2 was mixed in 1% sodium hyaluronate gel (final H2O2 concentration 0.5%) before administration to slow drug release and minimize local discomfort. The mixture was injected intratumorally under ultrasound guidance twice weekly 1 hour before RT. The primary endpoint was patient-reported maximum intratumoral pain intensity before and 24 hours postinjection. Secondary endpoints included grade ≥3 skin toxicity and tumor response by ultrasound. Blood samples were collected before, during, and at the end of treatment for cell-death and immune marker analysis. RESULTS: Compliance with H2O2 and RT was 100%. Five of 12 patients reported moderate pain after injection (grade 2 Common Terminology Criteria for Adverse Events v4.02) with median duration 60 minutes (interquartile range, 20-120 minutes). Skin toxicity was comparable to RT alone, with maintained partial/complete tumor response relative to baseline in 11 of 12 patients at last follow-up (median 12 months). Blood marker analysis highlighted significant associations of TRAIL, IL-1ß, IL-4, and MIP-1α with tumor response. CONCLUSIONS: Intratumoral H2O2 with RT is well tolerated with no additional toxicity compared with RT alone. If efficacy is confirmed in a randomized phase 2 trial, the approach has potential as a cost-effective radiation response enhancer in multiple cancer types in which locoregional control after RT alone remains poor.

Anti-hypertensive effect of hydrogen peroxide acting centrally.

Intracerebroventricular (icv) injection of hydrogen peroxide (H2O2) or the increase of endogenous H2O2 centrally produced by catalase inhibition with 3-amino-1,2,4-triazole (ATZ) injected icv reduces the pressor responses to central angiotensin II (ANG II) in normotensive rats. In the present study, we investigated the changes in the arterial pressure and in the pressor responses to ANG II icv in spontaneously hypertensive rats (SHRs) and 2-kidney, 1-clip (2K1C) hypertensive rats treated with H2O2 injected icv or ATZ injected icv or intravenously (iv). Adult male SHRs or Holtzman rats (n = 5-10/group) with stainless steel cannulas implanted in the lateral ventricle were used. In freely moving rats, H2O2 (5 µmol/1 µl) or ATZ (5 nmol/1 µl) icv reduced the pressor responses to ANG II (50 ng/1 µl) icv in SHRs (11 ± 3 and 17 ± 4 mmHg, respectively, vs. 35 ± 6 mmHg) and 2K1C hypertensive rats (3 ± 1 and 16 ± 3 mmHg, respectively, vs. 26 ± 2 mmHg). ATZ (3.6 mmol/kg of body weight) iv alone or combined with H2O2 icv also reduced icv ANG II-induced pressor response in SHRs and 2K1C hypertensive rats. Baseline arterial pressure was also reduced (-10 to -15 mmHg) in 2K1C hypertensive rats treated with H2O2 icv and ATZ iv alone or combined and in SHRs treated with H2O2 icv alone or combined with ATZ iv. The results suggest that exogenous or endogenous H2O2 acting centrally produces anti-hypertensive effects impairing central pressor mechanisms activated by ANG II in SHRs or 2K1C hypertensive rats.

In vitro bleaching effect of hydrogen peroxide with different time of exposition and concentration on shear bond strength of orthodontic brackets to human enamel: A meta-analysis of in vitro studies.

INTRODUCTION: Controversy exists regarding the effect of bleaching on shear bond strength (SBS) of orthodontic brackets to enamel. This study aims to do a review and meta-analysis on the effect of bleaching with hydrogen peroxide on SBS according to the interval between bleaching and bonding to human enamel and the concentration of Hydrogen Peroxide. METHODS: An electronic search of the literature was performed in Scopus, PubMed and Cochrane databases including CENTRAL and Cochrane library for relevant in vitro studies on the effect of bleaching with hydrogen peroxide on shear bond strength of human enamel, published until June 2018. Modified Cochrane Risk of Bias tool was used to assess the quality of the individual studies. AMSTAR tool was used for assessing the quality of the study. RESULTS: Nineteen studies were included in the qualitative analysis. Regardless of the interval between bleaching and bonding, reduction in SBS was not statistically significant when the hydrogen peroxide of less than 35% is used. Bleaching with 35% hydrogen reduces SBS when the bonding is conducted immediately (P<0.0001) or the time interval was shorter than one day (P<0.0005). On the other hand, use of high dose hydrogen peroxide resulted in a statistically significant reduction in SBS irrespective of the time interval between the procedures (P<0.05 for all categories of time interval). CONCLUSION: Bleaching with hydrogen peroxide decreases the SBS of brackets in patients undergoing orthodontic treatment especially if the time interval between bleaching and bonding procedures is short and a high concentration of hydrogen peroxide is used.

Evaluation of different concentrations of hydrogen peroxide solution (3% and 6%) as a potential new therapeutic option of nongenital warts: A randomized controlled triple-blinded clinical trial.

BACKGROUND: Warts are common viral skin infections caused by human papillomavirus. None of the available treatment modalities fulfills the criteria of an ideal treatment option. OBJECTIVES: To evaluate the efficacy and safety of hydrogen peroxide (HP) 3% and 6% solution as a topical treatment of nongenital warts. METHODS: This prospective randomized controlled study included 145 patients with nongenital warts. They were divided into three groups. Group 1 used topical hydrogen peroxide 6% solution under occlusion with a plastic tape for one hour daily for 6 weeks, group 2 used hydrogen peroxide 3% solution, and group 3 used normal saline 0.9% as a placebo. Patients were evaluated at the third and sixth weeks of treatment and 12 weeks after treatment completion. RESULTS: Treatment responses were significantly better in groups 1 and 2 than in group 3 with a better overall responses in group 1 than in group 2 (P = 0.0001*). Apart from mild hypopigmentation which was detected in only two patients in groups 1 and 2, no other side effects could be detected. Three months after treatment completion, no recurrence was observed. CONCLUSION: Hydrogen peroxide solution (3% and 6%) is an effective, safe, and cheap treatment modality for nongenital warts which can be used simply at home. Since the overall response was better with the 6% concentration, it should be the better therapeutic option.

Eskata (40% Hydrogen Peroxide Solution) for the Treatment of Seborrheic Keratoses

"Barnacles", "liverspots", "age spots": Seborrheic keratoses (SKs) have many different names, sizes, and clinical presentations in our patients. The only commonality among SKs is that patients despise them. While patients are initially concerned about their malignant potential, once they are reassured, most patients quickly transition from relief to request: "Can you get rid of them?" An observational study conducted across multiple dermatology practices found that SKs have a significant impact on quality of life, causing patients to adopt strategies to cover them and seek treatment for asymptomatic lesions.1 Given their benign potential, the only reason to remove an asymptomatic raised SK is cosmetic. When doing a cosmetic procedure, the acceptable risk is often lower given that the benefit for treatment is aesthetic. Ideally, a cosmetic intervention would have a wealth of evidence-based data and a favorable side effect profile. Eskata 40% hydrogen peroxide topical solution, the only FDA-approved drug for the treatment of raised SKs, strikes the perfect balance between efficacy and side effect profile.

Clinical Experience With 40% Hydrogen Peroxide Topical Solution for the Treatment of Seborrheic Keratosis

Despite reassurances about the benign nature of seborrheic keratoses (SKs), patients often request treatment due to cosmetic concerns or for symptomatic relief when SKs become irritated or pruritic. Treatment options include cryotherapy, surgical techniques, and topical therapies. In this study, we present two patients with SKs located on their face and neck who received in-office treatment with 40% Hydrogen Peroxide Topical Solution (Eskata™, HP40), a new FDA-approved topical therapy that has demonstrated efficacy in phase 3 trials. Compared to non-topical, more invasive techniques, HP40 may lead to less pigmentary changes, and may be more efficacious for SKs on the face and neck. Both patients received two treatment courses of HP40, which resulted in positive therapeutic outcomes, including the absence of scarring and pigmentary changes. In addition to the case presentations, we will discuss considerations for appropriate administration of HP40 to maximize clinical outcomes. J Drugs Dermatol. 2019;18(7 Suppl):s173-177.

Enhancing Outcomes in Seborrheic Keratosis: Using a Novel Treatment Solution

Seborrheic keratosis (SK) is an extremely common benign cutaneous lesion that often appears on individuals older than the age of 50. SK lesions can appear in numerous clinical variations, but typically, SKs present with a well-demarcated, "stuck-on" appearance having a waxy or keratotic surface. Even though SK lesions are usually benign, many individuals elect for SK treatment or removal due to cosmetic concerns. One study regarding SK appearance reported that 61% of women tried to conceal the appearance of the SKs by using certain hairstyles, make-up, and clothes. Conventional treatment for SK lesions ranges from cryosurgery to curettage. Although these removal methods are effective for SK treatment, each method contains a potential for side effects such as pigmentation changes, scarring, and discomfort before and after the procedure. Due to many of these concerns, patients prefer topical treatments for SKs, which has led to a new emerging topical containing hydrogen peroxide topical solution 40% (HP40; Eskata™). Here, we report the methods and results from an HP40 treatment for two individuals, each over 70 years old. Application of the topical solution was performed on each target SK, up to four times, with a 20-second application and 1 minute between applications. The two participants reported moderate success of HP40 in the removal of their SKs with minimal adverse effects. J Drugs Dermatol. 2019;18(7 Suppl):s178-182.

Selective Anticancer Therapy Using Pro-Oxidant Drug-Loaded Chitosan-Fucoidan Nanoparticles.

Pro-oxidant therapy exploiting pro-oxidant drugs that can trigger cytotoxic oxidative stress in cancer cells has emerged as an innovative strategy for cancer-specific therapy. Piperlongumine (PL) has gained great interest as a novel pro-oxidant agent, because it has an ability to trigger cancer-specific apoptosis through the increase of oxidative stress in cancer cells. However, the use of PL is limited in the clinic because of its hydrophobic nature. In this study, chitosan- and fucoidan-based nanoparticles were prepared for the effective intracellular delivery of PL into cancer cells. Chitosan and fucoidan formed nanoparticles by ionic gelation. The chitosan- and fucoidan-based nanoparticles (CS-F NPs) effectively encapsulated PL, and increased its water solubility and bioavailability. CS-F NPs showed very low cytotoxicity in human prostate cancer cells, demonstrating its high potential for in vivo applications. The PL-loaded chitosan-fucoidan nanoparticles (PL-CS-F NPs) efficiently killed human prostate cancer cells via PL-induced intracellular reactive oxygen species (ROS) generation. This study demonstrates that CS-F NPs are promising natural polymer-based drug carriers for safe and effective PL delivery.

Does juvenile hormone prompt oxidative stress in male damselflies?

In invertebrates, it has recently been reported that secondary sexual characteristics (SSCs) reflect the antioxidant defense of their bearers, but it is not known what physiological link maintains the honesty of those signals. Here, we used the damselfly Hetaerina americana to test whether juvenile hormone plays such a role. First, we analyzed whether oxidative damage is a real threat in natural damselfly populations by examining the accumulation of oxidized guanines as a function of age in males. Then, we injected paraquat (a pro-oxidant agent) and added the juvenile hormone analog methoprene (JHa) to the experimental group and the JHa vehicle (acetone) to the control group, to determine whether JHa increases the levels of pro-oxidants and antioxidants. We found that DNA oxidation increased with age, and that levels of hydrogen peroxide and superoxide dismutase, but not catalase or glutathione, were elevated in the JHa group compared with the control group. We propose that juvenile hormone is a mediator of the relationship between SSCs and antioxidant capacity and, based on the literature, we know that JHa suppresses the immune response. We therefore suggest that juvenile hormone is a molecular mediator of the general health of males, which is reflected in their SSCs.

Intravitreal Injection of Hydrogen Peroxide Induces Acute Retinal Degeneration, Apoptosis, and Oxidative Stress in Mice.

PURPOSE: Oxidative stress is a common pathological condition for multiple retinal diseases. Hydrogen peroxide (H2O2) has been applied as an oxidative stress inducer for the in vitro studies. Here, we report the in vivo effect of H2O2 exposure to the mouse retina and its underlying mechanism. METHODS: The H2O2 or saline solution was intravitreally injected into the eyes of female C57BL/6J mice for two consecutive days. The retinal structure was evaluated by in vivo imaging using spectral domain optical coherence tomography (OCT) and validated by histological assessment as well as retinal marker expression. In addition, retinal stress, cell apoptosis, and antioxidant enzyme expression were also determined. RESULTS: Retinal and outer nuclear layer thickness thinning was observed at days 7 and 14 by OCT imaging with the treatment of 10 µg H2O2, which was confirmed by the histopathological analysis. The expressions of photoreceptor (Rho, Rora, Rorb, and Rcvrn), bipolar cell (Chat and Calb2), and retinal pigment epithelial (Rpe65) markers were reduced in the H2O2-treated group, whereas the expression of retinal ganglion cell marker (Tubb3) was increased. TUNEL-positive cells were obviously found in the outer nuclear layer and inner nuclear layer of H2O2-treated mice but sparely found in the ganglion cell layer. Coherently, apoptotic gene expressions (Casp3, Casp9, Bax, and Parp8) were significantly increased in the retina with increasing dosages of H2O2, while Bcl2 expression was mildly decreased. In addition, the expressions of Gfap and antioxidant enzyme genes (Txn2, Sod2, and Gpx4) were significantly upregulated in the retina after the H2O2 treatment, compared to the vehicle control group. CONCLUSIONS: This study revealed that intravitreal injection of H2O2 induces acute retinal damage by increasing oxidative stress and cell apoptosis in the retina. This acute retinal degeneration mouse model could provide a platform for drug screening against oxidative stress and retinal diseases.

Anatomic Site-Specific Treatment Response With 40% Hydrogen Peroxide (w/w) Topical Formulation for Raised Seborrheic Keratoses: Pooled Analysis of Data from Two Phase 3 Studies.

OBJECTIVE: Seborrheic keratoses (SKs) may present in any non-glabrous skin, but data are limited on the response to treatment as based on the SK location. We aimed to understand the relationship between SK location and clearance with up to 2 treatments of 40% (w/w) hydrogen peroxide topical solution (HP40). METHODS: We conducted a sub-analysis of data pooled from two randomized, double-blind, vehicle (VEH)-controlled clinical trials, including 937 patients, each with 4 target SKs (N=3,748 SKs), with at least 1 on the face and 1 on the trunk or extremities. Treatment response was defined as 0 or 1 on a 4-point Physician's Lesion Assessment (PLA) scale (0=clear; 1=near-clear) after up to 2 applications, 3 weeks apart, and was assessed by SK location (face, trunk, and extremity). Local skin reactions were stratified by anatomic location and categorized based on immediate and delayed post-treatment reactions. Sensitivity analysis was conducted using the mean-per-patient (MPP) percent of SKs that are clear or near-clear at day 106. RESULTS: Treatment response was greater with HP40 versus VEH regardless of anatomic location of the SK. Clear or near-clear SKs with HP40 was observed in 65% of facial SKs (vs 10% VEH), 46% of truncal SKs (vs 5% VEH), and 38% of extremity SKs (vs 9% VEH). Facial SKs were more likely to be clear or near clear after a single treatment (43%), versus SKs on the trunk (31%) or extremities (14%). Most common immediate reactions with HP40 were erythema, stinging, and edema, which resolved to none or mostly mild within a week. Delayed reactions such as dyspigmentation and scarring occurred at low rates and were least reported for the facial SKs. CONCLUSIONS: SK clearance with HP40 was highest among SKs on the face and lowest among SKs on the extremities. Dyspigmentation rates were lowest among SKs treated on the face. Anatomic location of SK was a predictor of both treatment response and risk of dyspigmentation with HP40 application. ClinicalTrials.gov listings: NCT02667236 and NCT02667275 J Drugs Dermatol. 2018;17(10):1092-1098.