Background/Objectives: Wound healing relies on oxygen availability and controlled reactive oxygen species (ROS) signaling. Excessive ROS hinder repair, whereas low, sustained levels promote angiogenesis, antimicrobial defense, and tissue regeneration. Oxygen-enriched oleic matrices (OEOMs), generated by ozonating vegetable oils, combine a moist lipidic environment with continuous ROS and pH modulation. This review summarizes their mechanisms and clinical applications. Methods: We analyzed preclinical and clinical studies addressing the chemistry, mode of action, and translational use of OEOMs. Evidence was appraised across burns, surgical wounds, oncologic settings, pediatrics, and chronic ulcers. Results: Ozonation stabilizes oleic acid into gel-like matrices that act as wound barriers while releasing hydrogen peroxide, oxygen, and fatty acids. These mechanisms reduce microbial growth, lower pH, and support keratinocyte and fibroblast activity. Clinically, OEOMs accelerate healing, reduce pain, and improve outcomes in burns, oral ulcers, and Stevens–Johnson syndrome. Postsurgical applications—including hidradenitis suppurativa and pilonidal sinus disease—show improved closure, scar quality, and lower recurrence. In oncologic and reconstructive surgery, OEOMs decrease pain, enhance satisfaction, and facilitate outpatient care. Chronic leg ulcers demonstrate granulation, re-epithelialization, pain reduction, and absence of infections. Most studies are case series or small cohorts, with consistent safety and tolerability. Conclusions: EOMs provide combined antimicrobial and pro-regenerative effects across diverse wound types. Current evidence supports their role as innovative wound dressings, though larger randomized trials are needed to validate efficacy and cost-effectiveness.

Hypoxia is a common challenge in fetal development. Short-term acute episodes occur during labour owing to uterine contractions or umbilical cord compression. In response, the fetus prioritizes oxygen and nutrient delivery to the brain, heart and adrenal glands at the expense of other organs, a mechanism known as the fetal brain-sparing response. However, prolonged fetal hypoxia can occur in many conditions, including placental insufficiency, pre-eclampsia, high-altitude pregnancy and fetal congenital heart disease. Chronic hypoxia increases placental and fetal oxidative stress, triggering increased long-term cardiovascular risks in adult offspring, including hypertension and coronary artery disease. Antioxidants could potentially prevent this. However, as reactive oxygen species play a crucial role in the fetal brain-sparing response, excessive antioxidant use could weaken fetal defences against acute hypoxia, increasing the risk of hypoxic-ischaemic encephalopathy. Thus, for clinical use, an antioxidant should protect against programmed cardiovascular disease while preserving fetal brain sparing. This review summarizes preclinical evidence on the efficacy of antioxidants in preventing cardiovascular disease in the offspring of hypoxic pregnancy. We compare their effects on fetal brain sparing, highlighting the ability of the mitochondria-targeted antioxidant MitoQ to protect against programmed cardiovascular disease while preserving fetal brain sparing and outlining steps for clinical translation.This article is part of the discussion meeting issue 'Pregnancy at high altitude: the challenge of hypoxia'.

Dysregulation of redox homeostasis is implicated in the ageing process and the pathology of age-related diseases. To study redox signalling by H2O2 in vivo, we established a redox-shifted model by manipulating levels of the H2O2-degrading enzyme catalase in Drosophila. Here we report that ubiquitous over-expression of catalase robustly extends lifespan in females. As anticipated, these flies are strongly resistant to a range of oxidative stress challenges, but interestingly are sensitive to starvation, which could not be explained by differences in levels of energy reserves. This led us to explore the contribution of autophagy, which is an important mechanism for organismal survival in response to starvation. We show that autophagy is essential for the increased lifespan by catalase upregulation, as the survival benefits are completely abolished upon global autophagy knock-down. Furthermore, using a specific redox-inactive knock-in mutant, we highlight the in vivo role of a key regulatory cysteine residue in Atg4a, which is required for the lifespan extension in our catalase model. Altogether, these findings confirm the redox regulation of autophagy in vivo as an important modulator of longevity.

Early stroke detection and treatment are critical for improving patient outcomes. Optical brain pulse monitoring (OBPM) uses red and infrared light to capture brain pulse waveforms reflecting arteriole-to-venous pressure levels driving microvascular blood flow. This study assessed OBPMs potential to detect middle cerebral artery occlusion (MCAo) and reperfusion in a clinically relevant sheep model. Stroke was induced in 11 Merino wethers via 4-hour occlusion of the right MCA, followed by 6 hours of reperfusion. OBPM recordings were taken at baseline, MCAo, early and late reperfusion. The OBPM brain pulse waveform classes were classified based on the presence of arterial or central venous circulation wave features. Magnetic resonance imaging assessed infarct volume at 2 hours post-reperfusion. Invasive brain tissue oxygen and intracranial pressures were also monitored. The OBPM brain pulse waveform classes changed during MCAo and reperfusion (p <0.0001). MCAo was associated brain pulses with venous circulation features (p = 0.0007). Reperfusion was associated with the return of arterial circulation features (p = 0.001). Early reperfusion was also associated with an increase in the brain pulse amplitude (p < 0.05) and the respiratory wave amplitude (p < 0.05). OBPM may aid in early stroke detection and reperfusion assessment following intervention. ### Competing Interest Statement B.D. is the founder and Chief Scientific Officer of Cyban, Pty Ltd and reports grants and personal fees from Cyban, during the conduct of the study; In addition, B.D. has patents US9717446B2 and WO2008134813A1 issued to Cyban. E.J.T., S.A.G., S.P., S.W.C, and J.H. are paid employees of Cyban. J.M.S, was a paid employee at the time of conducting the research. H.P., T.K. and M.P.M are founders and shareholders of Camoxis Pharmaceuticals Ltd. The remaining authors report no conflict of interest.

Carotid body glomus cells are essential for stimulating breathing in response to hypoxia. They contain specialized mitochondria in which hypoxia induces the accumulation of NADH and H2O2 that modulate membrane ion channel activity. We investigated whether hypoxia induces reverse electron transport (RET) at mitochondrial complex I (MCI). We studied glomus cells from mice with a mutation in ND6, a core protein of MCI, which maintain normal MCI NADH dehydrogenase activity but cannot catalyze RET. The ND6 mutation increases the propensity of MCI to deactivate, and glomus cells with deactivated MCI are insensitive to acute hypoxia. These findings further indicate that MCI function is necessary for glomus cell responsiveness to hypoxia, although MCI RET does not seem to be required for this process.

Macrophages stimulated by lipopolysaccharide (LPS) generate mitochondria-derived reactive oxygen species (mtROS) that act as antimicrobial agents and redox signals; however, the mechanism of LPS-induced mitochondrial superoxide generation is unknown. Here we show that LPS-stimulated bone-marrow-derived macrophages produce superoxide by reverse electron transport (RET) at complex I of the electron transport chain. Using chemical biology and genetic approaches, we demonstrate that superoxide production is driven by LPS-induced metabolic reprogramming, which increases the proton motive force (∆p), primarily as elevated mitochondrial membrane potential (Δψm) and maintains a reduced CoQ pool. The key metabolic changes are repurposing of ATP production from oxidative phosphorylation to glycolysis, which reduces reliance on F1FO-ATP synthase activity resulting in a higher ∆p, while oxidation of succinate sustains a reduced CoQ pool. Furthermore, the production of mtROS by RET regulates IL-1β release during NLRP3 inflammasome activation. Thus, we demonstrate that ROS generated by RET is an important mitochondria-derived signal that regulates macrophage cytokine production. Casey et al. explore the basic mechanisms of mitochondrial superoxide production and its impact on interleukin-1β production in LPS-treated macrophages.

Diabetic wounds are complicated by underlying peripheral vasculopathy. Reliance on vascular endothelial growth factor (VEGF) therapy to improve perfusion makes logical sense, yet clinical study outcomes on rescuing diabetic wound vascularization have yielded disappointing results. Our previous work has identified that low endothelial phospholipase Cγ2 (PLCγ2) expression hinders the therapeutic effect of VEGF on the diabetic ischemic limb. In this work, guided by single-cell RNA sequencing of human wound edge, we test the efficacy of gene-targeted therapeutic demethylation intending to improve VEGF-mediated neovascularization. PLCγ2 expression was diminished in all five identified diabetic wound-edge endothelial subclusters encompassing arterial, venous, and capillary cells. Such low expression was associated with hypermethylated PLCγ2 promoter. PLCγ2 promoter was also hypermethylated at murine diabetic ischemic wound edge. To specifically demethylate endothelial PLCγ2 promoter during VEGF therapy, a CRISPR-dCas9-based demethylation cocktail was delivered to the ischemic wound edge using tissue nanotransfection (TNT) technology. Demethylation-based upregulation of PLCγ2 during VEGF therapy improved wound tissue blood flow with an increased abundance of von Willebrand factor (vWF)+/PLCγ2+ vascular tissue elements by activating p44/p42-mitogen-activated protein kinase (MAPK) → hypoxia-inducible factor [HIF]-1α pathway. Taken together, TNT-based delivery of plasmids to demethylate the PLCγ2 gene promoter activity led to significant improvements in VEGF therapy for cutaneous diabetic wounds, resulting in better perfusion and accelerated wound closure.

B-cell acute lymphoblastic leukemia (B-ALL) is a leading cause of death in childhood and outcomes in adults remain dismal. There is therefore an urgent clinical need for therapies that target the highest risk cases. Mutations in the histone acetyltransferase CREBBP confer high-risk and increased chemoresistance in ALL. Performing a targeted drug-screen in isogenic human cell lines, we identify a number of small molecules that specifically target CREBBP-mutated B-ALL, the most potent being the BCL2-inhibitor Venetoclax. Of note, this acts through a non-canonical mechanism resulting in ferroptotic rather than apoptotic cell death. CREBBP-mutated cell lines show differences in cell-cycle, metabolism, lipid composition and response to oxidative stress, predisposing them to ferroptosis, which are further dysregulated upon acquisition of Venetoclax resistance. Lastly, small-molecule inhibition of CREBBP pharmacocopies CREBBP-mutation, sensitizing B-ALL cells, regardless of genotype, to Venetoclax-induced ferroptosis in-vitro and in-vivo, providing a promising drug combination for broader clinical translation in B-ALL.

Type 2 Diabetes (T2D) can lead to diabetic cardiomyopathy (dbCM), which is characterised by chronic, systemic inflammation, disrupted metabolism and impaired cardiac function. However, whether cardiac inflammation is present in dbCM and causally linked to metabolic remodelling remains unknown. AZD1656 (AZD), an activator of glucokinase, was postulated to provide glycaemic control in T2D by acting on in the pancreas and liver. However, AZD failed to control hyperglycaemia in clinical trials. Nevertheless, testing of the drug in COVID-19 T2D patients as part of the ARCADIA trial indicated an immunomodulatory effect. Therefore, we used the db/db mouse model of dbCM and an integrated in vivo and ex vivo experimental approach to examine the effects of AZD on cardiac functional and metabolic disturbances and inflammation. 20-week db/db mice displaying the features of human dbCM (obesity, hyperglycaemia and diastolic dysfunction) treated for six weeks with AZD showed improved metabolic remodelling, attenuated diastolic dysfunction, reduced infarct size and improved functional post-ischemic recovery compared to untreated dbCM, alongside an improved cardiac immunophenotype, including reduced T cell-mediated fibrosis and B cell infiltration. Therefore, targeting of immunometabolism may offer a new therapeutic approach to treat cardiac dysfunction and metabolic dysregulation and reduce infarct size in dbCM.

The diversity of cellular phospholipids, crucial for membrane homeostasis and function, arises from enzymatic remodeling of their fatty acyl chains. In this work, we reveal that poorly understood TRAM-LAG1-CLN8 domain (TLCD)-containing proteins are phospholipid remodeling enzymes. We demonstrate that TLCD1 is an evolutionarily conserved lysophosphatidylethanolamine acyltransferase, which regulates cellular phospholipid composition and generates previously undescribed fatty acid and thiamine (vitamin B1) esters as its secondary products. Furthermore, we establish that human TLCD protein CLN8, mutations of which cause fatal neurodegenerative Batten disease, is a lysophosphatidylglycerol acyltransferase. We show that CLN8 catalyzes the essential step in the biosynthesis of bis(monoacylglycero)phosphate, a phospholipid critical for lysosome function. Our study unveils a family of acyltransferases integral to cellular membrane phospholipid homeostasis and human disease.

During recent decades, changes in lifestyle have led to widespread nutritional obesity and its related complications. Remodelling adipose tissue as a therapeutic goal for obesity and its complications has attracted much attention and continues to be actively explored. The endothelium lines all blood vessels and is close to all cells, including adipocytes. The endothelium has been suggested to act as a paracrine organ. We explore the role of endothelial insulin-like growth factor-1 receptor (IGF-1R), as a paracrine modulator of white adipose phenotype. We show that a reduction in endothelial IGF-1R expression in the presence of high-fat feeding in male mice leads to depot-specific beneficial white adipose tissue remodelling, increases whole-body energy expenditure and enhances insulin sensitivity via a non-cell-autonomous paracrine mechanism. We demonstrate that increased endothelial malonate may be contributory and that malonate prodrugs have potentially therapeutically relevant properties in the treatment of obesity-related metabolic disease.

Impaired mitochondrial bioenergetics in macrophages can drive hyperinflammatory cytokine responses, but whether this may also be caused by inherited mtDNA mutations is unknown. Here, we address this question using a multi-omic approach that integrates super-resolution imaging and metabolic analyses to profile macrophages from a mouse model of mitochondrial disease arising from a heteroplasmic mutation (m.5019A>G) in the mitochondrial tRNA for alanine. These m.5019A>G macrophages exhibit defects in respiratory chain complexes and oxidative phosphorylation (OxPhos) due to decreased intra-mitochondrial translation. To adapt to this metabolic stress, mitochondrial fusion, reductive glutamine metabolism, and aerobic glycolysis are all increased. Upon inflammatory activation, type I interferon (IFN-I) release is enhanced, while the production of pro-inflammatory cytokines and oxylipins are restrained in m.5019A>G macrophages. Finally, an in vivo endotoxemia model using m.5019A>G mice reveal elevated IFN-I levels and sickness behaviour. In conclusion, our study identifies an unexpected imbalance in innate immune signalling in response to a pathogenic mtDNA mutation, with important implications for the progression of pathology in patients with mtDNA diseases. ### Competing Interest Statement The authors have declared no competing interest.

Heart failure with preserved ejection fraction (HFpEF) poses a significant global health challenge, disproportionately affecting women. Diabetic women with HFpEF represent a high-risk subgroup, particularly after experiencing ST-segment elevation myocardial infarction (STEMI), exhibiting increased mortality compared to men. While prolonged door-to-balloon (DTB) times, reflecting delayed reperfusion, are a critical factor in STEMI outcomes, they alone do not fully capture the observed outcome variability in diabetic women. Using an integrated clinical and pre-clinical approach this study aimed to investigate the relative contributions of metabolic dysfunction and coronary artery disease (CAD) in type 2 diabetes (T2D) to STEMI outcomes in women, beyond the impact of DTB time. A retrospective case–control study analysed female STEMI patients undergoing primary percutaneous coronary intervention (pPCI, n = 40 T2D, n = 40 non-diabetic controls), comparing clinical characteristics, treatment strategies, and early outcomes. A preclinical model (female db/db mice) assessed cardiac function via echocardiography, Langendorff perfusions, and ischemia–reperfusion protocols. Metabolome of heart, liver, and skeletal muscle was assessed by 1H NMR spectroscopy. Our study reveals significantly higher mortality, impaired left ventricular function post-pPCI, and increased implantable cardioverter-defibrillator (ICD) implantation rates in diabetic STEMI patients, irrespective of DTB time, when compared to non-diabetic controls. Elevated inflammatory markers, acute hyperglycaemia and evidence of cardio-hepatic damage were identified in T2D patients. db/db mice exhibited analogous T2D-associated pathophysiology, including increased ischemia–reperfusion injury exacerbated by metabolic disturbances in the myocardium, liver, and skeletal muscle versus non-diabetic controls. In diabetic women, multiple factors beyond reperfusion delays exacerbate acute myocardial injury. This necessitates the development of sex-specific strategies to manage the cardiovascular complications of diabetic HFpEF. The db/db mouse model provides a relevant preclinical tool for future research as it mimics human T2D-associated HFpEF and STEMI outcome.

Central to the development of heart failure with preserved ejection fraction (HFpEF) is the redox disruption of metabolic processes; however, the underlying mechanisms are not fully understood. This study utilized a murine model (ND6) carrying a homoplasmic mitochondrial DNA point mutation (ND6 G13997A), which maintains functional NADH oxidation but lacks the site-specific reactive oxygen species (ROS) generation via reverse electron transport (RET). We demonstrate that mice with RET-ROS deficiency have reduced exercise capacity despite higher lean body mass, impaired resilience to high-fat/high-sucrose dietary stress, and cardiac hypertrophy with diastolic dysfunction. Importantly, dobutamine-induced stress elevated succinate levels in the heart, accompanied by RET-ROS production in wild-type but not in ND6 mice. Furthermore, ND6 mice showed perturbation in metabolite profiles following dobutamine stress. Mechanistically, the ND6 heart had an upregulated expression of fatty acid transport, oxidation, and synthesis genes (CD36, Cpt1b, Acly, Fas, Elovl6, and Scd1) and increased protein levels of lipid metabolism regulators (acetyl-CoA carboxylase and perilipin 2). Interestingly, 8 wk of forced treadmill running increased acetyl-CoA abundance, alleviated metabolic stress, and improved diastolic function in RET-ROS mutant hearts. In summary, these findings reveal a critical role for RET-ROS in regulating exercise capacity and cardiometabolic health, identifying it as a potentially selective target for modulating cardiac metabolism.NEW & NOTEWORTHY Loss of reverse electron transport (RET)-reactive oxygen species (ROS) impairs diastolic function and exercise capacity, which can be improved by long-term aerobic exercise. RET-ROS may act as a modulator of cardiac metabolism.

BACKGROUND:Mitochondria-targeted S-nitrosothiol (MitoSNO) is thought to protect against ischemia-reperfusion injury by suppressing reactive oxygen species production upon reperfusion. We investigated whether intravenous MitoSNO administration after resuscitation improves outcomes following cardiac arrest (CA) in rats. METHODS:Adult male rats were subjected to 10 min of asphyxial CA followed by cardiopulmonary resuscitation (CPR). Upon return of spontaneous circulation (ROSC), animals were randomized to receive either vehicle or MitoSNO (400 ng/kg total), administered intravenously in two doses: immediately and 1 h post-CA. The dosing regimen was selected based on findings from an exploratory dose-titration study. Neurological function and survival were assessed over a 72-h period. Cardiac function was evaluated using transthoracic echocardiography, while cerebral blood flow (CBF) was measured via laser speckle contrast imaging. Brain injury and oxidative stress were assessed through Fluoro-Jade B staining, western blotting, and enzyme-linked immunosorbent assay. RESULTS:MitoSNO significantly improved 72-h survival and neurological function compared to vehicle controls (100 % vs. 40 %, P < 0.05). Echocardiography showed enhanced left ventricular ejection fraction and cardiac index at 24 h post-ROSC in MitoSNO-treated animals compared with vehicle (89.8 ± 3.1 % vs 83.8 ± 7.5 %; P < 0.05, 69.2 ± 13.2 ml/min/100g vs 46.3 ± 11.6 ml/min/100g; P < 0.01). MitoSNO also attenuated post-CA cerebral hypoperfusion, as evidenced by preserved relative CBF on laser speckle imaging. Western blotting revealed reduced levels of 3-nitrotyrosine and cleaved caspase-3 in brain tissue, indicating decreased nitrosative stress and apoptosis. Immunohistochemistry demonstrated suppression of neuronal degeneration in vulnerable brain regions. CONCLUSIONS:Post-resuscitation administration of MitoSNO significantly improved survival and neurological outcomes following CA in rats. These benefits were associated with enhanced cardiac function, preserved cerebral perfusion, and reduced oxidative stress and apoptosis in the brain.

The overproduction of reactive oxygen species (ROS) and mitochondrial dysregulation are regarded as key mechanisms in the progression of cardiac remodelling in cardiometabolic diseases including heart failure. Conventional treatments are often ineffective as they do not specifically target the underlying pathological mechanisms. Mitoquinone mesylate (MitoQ), a mitochondrial-targeted antioxidant has been reported to be protective against vascular dysfunction in hypertension, diabetic kidney disease and alcohol-induced liver damage. However, the cardioprotective potential of MitoQ to limit oxidative stress-induced mitochondrial remodelling in cardiomyocytes has not been fully resolved. We sought to investigate the effect of MitoQ and its mitochondrial-targeting moiety dodecyl-triphenylphosphonium (dTPP) on hydrogen peroxide-induced overproduction of ROS, mitochondrial dysregulation and cell death in H9C2 rat cardiomyoblasts (H9C2-rCM) and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Cardiomyocytes were exposed to acute or chronic treatment (5-60 min or 48 h) of vehicle control (0.0001 % Ultrapure Milli-Q water), hydrogen peroxide (100 μM) ± MitoQ (1 μM) or dTPP (1 μM) control. Hydrogen peroxide-induced overproduction of ROS, extracellular superoxide, mitochondrial ROS, mitochondrial hyperpolarisation and cell death were significantly blunted by MitoQ, but not dTPP, suggesting that the coenzyme Q10 moiety of MitoQ is protective under these conditions. Interestingly, both MitoQ and dTPP exhibited a pro-mitochondrial fusion effect by preserving mitochondrial network and reducing mitochondrial fragmentation in oxidative stress conditions. Overall, our findings confirm the cytoprotective potential of MitoQ to limit oxidative stress-induced adverse mitochondrial remodelling and dysregulation that is clinically observed in cardiometabolic-induced cardiac dysfunction in the failing heart.