Activation of Heme Metabolism Promotes Tissue Health After Intraarticular Injury or Surgical Exposure.

Posttraumatic osteoarthritis (PTOA) is a well-recognized public health burden without any disease modifying treatment. This occurs despite noted advances in surgical care in the past 50 years. Mitochondrial oxidative damage pathways initiate PTOA after severe injuries like intraarticular fracture that often require surgery and contribute to PTOA after less severe injuries that may or may not require surgery like meniscal injuries.

A reciprocal relationship between mitochondria and lipid peroxidation determines the chondrocyte intracellular redox environment.

In orthopedic research, many studies have applied vitamin E as a protective antioxidant or used tert-butyl hydroperoxide to induce oxidative injury to chondrocytes. These studies often support the hypothesis that joint pathology causes oxidative stress and increased lipid peroxidation that might be prevented with lipid antioxidants to improve cell survival or function and joint health; however, lipid antioxidant supplementation was ineffective against osteoarthritis in clinical trials and animal data have been equivocal. Moreover, increased circulating vitamin E is associated with increased rates of osteoarthritis.

Mitochondrial uncoupling proteins protect human airway epithelial ciliated cells from oxidative damage.

Apical cilia on epithelial cells defend the lung by propelling pathogens and particulates out of the respiratory airways. Ciliated cells produce ATP that powers cilia beating by densely grouping mitochondria just beneath the apical membrane. However, this efficient localization comes at a cost because electrons leaked during oxidative phosphorylation react with molecular oxygen to form superoxide, and thus, the cluster of mitochondria creates a hotspot for oxidant production.

Stability of aqueous solutions of ascorbate for basic research and for intravenous administration.

Ascorbate (vitamin C) can rapidly oxidize in many near-neutral pH, aqueous solutions. We report on the stability of ascorbate solutions prepared for infusion into patients using standard pharmacy protocols, for example, 75 g of ascorbate/L in water for infusion. The concentration of ascorbate was monitored for changes over time using direct UV-Vis spectroscopy.

Magnetic Resonance Imaging of Iron Metabolism with T2* Mapping Predicts an Enhanced Clinical Response to Pharmacologic Ascorbate in Patients with GBM.

Purpose: Pharmacologic ascorbate (P-AscH-) is hypothesized to be an iron (Fe)-dependent tumor-specific adjuvant to chemoradiation in treating glioblastoma (GBM). This study determined the efficacy of combining P-AscH- with radiation and temozolomide in a phase II clinical trial while simultaneously investigating a mechanism-based, noninvasive biomarker in T2* mapping to predict GBM response to P-AscH- in humans.

Patients And Methods: The single-arm phase II clinical trial (NCT02344355) enrolled 55 subjects, with analysis performed 12 months following the completion of treatment.

Pharmacologic Ascorbate and DNMT Inhibitors Increase DUOX Expression and Peroxide-Mediated Toxicity in Pancreatic Cancer.

Recent studies have demonstrated an important role for vitamin C in the epigenetic regulation of cancer-related genes via DNA demethylation by the ten-eleven translocation (TET) methylcytosine dioxygenase enzymes. DNA methyltransferase (DNMT) reverses this, increasing DNA methylation and decreasing gene expression. Dual oxidase (DUOX) enzymes produce hydrogen peroxide (HO) in normal pancreatic tissue but are silenced in pancreatic cancer (PDAC).

Ascorbate mediates the non-enzymatic reduction of nitrite to nitric oxide.

Nitric oxide (NO) generated by nitric oxide synthases is involved in many physiological and pathophysiological processes. However, non-enzymatic formation of NO also occurs . Here we investigated the production of NO from nitrite, as facilitated by ascorbate, over the pH range of 2.

Changes in metabolic landscapes shape divergent but distinct mutational signatures and cytotoxic consequences of redox stress.

Mutational signatures discerned in cancer genomes, in aging tissues and in cells exposed to toxic agents, reflect complex processes underlying transformation of cells from normal to dysfunctional. Due to its ubiquitous and chronic nature, redox stress contributions to cellular makeover remain equivocal. The deciphering of a new mutational signature of an environmentally-relevant oxidizing agent, potassium bromate, in yeast single strand DNA uncovered a surprising heterogeneity in the mutational signatures of oxidizing agents.

The role of mitochondria in pharmacological ascorbate-induced toxicity.

At pharmacological levels, ascorbate (P-AscH) acts as a pro-oxidant by generating HO, depleting ATP in sensitive cells leading to cell death. The aim of this study was to determine the role of ATP production by oxidative phosphorylation or glycolysis in mechanisms of resistance to P-AscHinduced cell death. Pancreatic cancer cells were used to generate ρ cells by mitochondrial overexpression of the Y147A mutant uracil-N-glycosylase or Herpes Simplex Virus protein.

Pharmacological Ascorbate Enhances Chemotherapies in Pancreatic Ductal Adenocarcinoma.

Objectives: Pharmacological ascorbate (P-AscH - , high-dose, intravenous vitamin C) has shown promise as an adjuvant therapy for pancreatic ductal adenocarcinoma (PDAC) treatment. The objective of this study was to determine the effects of P-AscH - when combined with PDAC chemotherapies.

Methods: Clonogenic survival, combination indices, and DNA damage were determined in human PDAC cell lines treated with P-AscH - in combination with 5-fluorouracil, paclitaxel, or FOLFIRINOX (combination of leucovorin, 5-fluorouracil, irinotecan, oxaliplatin).

Extracellular biomolecular free radical formation during injury.

Determine if oxidative damage increases in articular cartilage as a result of injury and matrix failure and whether modulation of the local redox environment influences this damage. Osteoarthritis is an age associated disease with no current disease modifying approaches available. Mechanisms of cartilage damage in vitro suggest tissue free radical production could be critical to early degeneration, but these mechanisms have not been described in intact tissue.

Pharmacological ascorbate improves the response to platinum-based chemotherapy in advanced stage non-small cell lung cancer.

Purpose: Platinum-based chemotherapy with or without immunotherapy is the mainstay of treatment for advanced stage non-small cell lung cancer (NSCLC) lacking a molecular driver alteration. Pre-clinical studies have reported that pharmacological ascorbate (P-AscH-) enhances NSCLC response to platinum-based therapy. We conducted a phase II clinical trial combining P-AscH- with carboplatin-paclitaxel chemotherapy.

TREM-1 is required for enhanced OpZ-induced superoxide generation following priming.

Inflammatory agents, microbial products, or stromal factors pre-activate or prime neutrophils to respond to activating stimuli in a rapid and aggressive manner. Primed neutrophils exhibit enhanced chemotaxis, phagocytosis, and respiratory burst when stimulated by secondary activating stimuli. We previously reported that Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) mediates neutrophil effector functions such as increased superoxide generation, transepithelial migration, and chemotaxis.

Electron Spin Resonance Evaluation of Buccal Membrane Fluidity Alterations by Sodium Caprylate and L-Menthol.

The ability of sodium caprylate and l-menthol to fluidize phospholipid bilayers composed of lipids simulating the buccal epithelium was investigated using electron spin resonance (ESR) to evaluate the action of these agents as permeation enhancers. 5-Doxyl stearic acid (5-DSA) and 16-doxyl stearic acid (16-DSA) were used as spin labels to identify alterations in membrane fluidity near the polar head groups or inner acyl regions of the lipid bilayer, respectively. The molecular motion of both 5-DSA and 16-DSA showed increased disorder near the polar and inner hydrophobic regions of the bilayer in the presence of sodium caprylate suggesting fluidization in both the regions, which contributes to its permeation enhancing effects.

Red blood cells contain enzymatically active GPx4 whose abundance anticorrelates with hemolysis during blood bank storage.

The antioxidant function of the phospholipid hydroperoxide glutathione peroxidase (GPx4) is vital for the homeostasis of many cell types, from neoplastic cells to normal erythroid precursors. However, some functional proteins in erythroid precursors are lost during the development of red blood cells (RBCs); whether GPx4 is maintained as an active enzyme in mature RBCs has remained unclear. Our meta-analyses of existing RBC proteomics and metabolomics studies revealed the abundance of GPx4 to be correlated with lipid-anchored proteins.

Prolonged Reactive Oxygen Species Production following Septic Insult.

The dysregulated host response and organ damage following systemic infection that characterizes a septic event predisposes individuals to a chronic immunoparalysis state associated with severe transient lymphopenia and diminished lymphocyte function, thereby reducing long-term patient survival and quality of life. Recently, we observed lasting production of reactive oxygen species (ROS) in mice that survive sepsis. ROS production is a potent mechanism for targeting infection, but excessive ROS production can prove maladaptive by causing organ damage, impairing lymphocyte function, and promoting inflammaging, concepts paralleling sepsis-induced immunoparalysis.

Catalase Modulates the Radio-Sensitization of Pancreatic Cancer Cells by Pharmacological Ascorbate.

Pancreatic cancer cells (PDACs) are more susceptible to an oxidative insult than normal cells, resulting in greater cytotoxicity upon exposure to agents that increase pro-oxidant levels. Pharmacological ascorbate (P-AscH), i.e.

Triphenylphosphonium derivatives disrupt metabolism and inhibit melanoma growth in vivo when delivered via a thermosensitive hydrogel.

Despite dramatic improvements in outcomes arising from the introduction of targeted therapies and immunotherapies, metastatic melanoma is a highly resistant form of cancer with 5 year survival rates of <35%. Drug resistance is frequently reported to be associated with changes in oxidative metabolism that lead to malignancy that is non-responsive to current treatments. The current report demonstrates that triphenylphosphonium(TPP)-based lipophilic cations can be utilized to induce cytotoxicity in pre-clinical models of malignant melanoma by disrupting mitochondrial metabolism.

Exposure to Static Magnetic and Electric Fields Treats Type 2 Diabetes.

Aberrant redox signaling underlies the pathophysiology of many chronic metabolic diseases, including type 2 diabetes (T2D). Methodologies aimed at rebalancing systemic redox homeostasis have had limited success. A noninvasive, sustained approach would enable the long-term control of redox signaling for the treatment of T2D.