Search Results (72)

Effective communication between multipotent mesenchymal stromal cells (MSCs) and endothelial cells (ECs) plays a critical role in the regulation of angiogenesis, especially under conditions of hypoxia. In addition to paracrine stimulation, direct intercellular contacts play an important role in the angiogenic interaction between MSCs and ECs, making them an important target for modulating vascular network restoration under ischemic conditions. The aim of this study was to determine the contribution of gap junctions (GJs) to the angiogenic response of MSCs and the EA.hy926 cell line (an Endothelial Cell Model) under acute hypoxic stress. In a cell co-culture model at 0.1% O₂ using a specific GJ inhibitor (carbenoxolone), molecular, cellular, and functional tests were performed: assessment of viability, proliferation, migration, secretion of angiogenic mediators, and expression of crucial genes. GJ blockade was accompanied by decreases in the proliferation and migration activity and angiogenic potential of the conditioned medium in in vitro and in ovo tests. These data highlight the importance of the GJ in coordinating the angiogenic response in conditions of acute hypoxia and can be used to develop protocols for regenerative medicine. Full article

Cardiovascular diseases (CVDs) remain a leading cause of mortality worldwide. According to the WHO, every year, there is an increase in the rate of death globally due to CVDs, stroke, and myocardial infarction. Several risk factors contribute to the development of CVDs, one of which is hypoxia, defined as a reduction in oxygen levels. This major stressor affects aerobic species and plays a crucial role in the development of cardiovascular disease. Research has uncovered the “hypoxia-inducible factors (HIFs) switch” and investigated the onset, progression, acute and chronic effects, and adaptations of hypoxia, particularly at high altitudes. The hypoxia signalling pathways are closely linked to natural rhythms such as the circadian rhythm and hibernation. In addition to genetic and evolutionary factors, epigenetics also plays an important role in postnatal cardiovascular responses to hypoxia. Oxidized LDL-C initiates atherosclerosis amidst oxidative stress, inflammation, endothelial dysfunction, and vascular remodelling in CVD pathogenesis. Anti-inflammatory and antioxidant biomarkers are needed to identify individuals at risk of cardiovascular events and enhance risk prediction. Among these, C-reactive protein (CRP) is a recognized marker of vascular inflammation in coronary arteries. Elevated pro-atherogenic oxidized LDL (oxLDL) expression serves as an antioxidant marker, predicting coronary heart disease in apparently healthy men. Natural antioxidants and anti-inflammatory molecules protect the heart by reducing oxidative stress, enhancing vasodilation, and improving endothelial function. For instance, the flavonoid quercetin exerts antioxidant and anti-inflammatory effects primarily by activating the Nrf2/HO-1 signaling pathway, thereby enhancing cellular antioxidant defense and reducing reactive oxygen species. Carotenoids, such as astaxanthin, exhibit potent antioxidant activity by scavenging free radicals and preserving mitochondrial integrity. The alkaloid berberine mediates cardiovascular benefits through activation of AMO-activated protein kinase (AMPK) and inhibition of nuclear factor kappa B [NF-kB] signalling, improving lipid metabolism and suppressing inflammatory cytokines. Emerging evidence highlights microRNAs (miRNAs) as potential regulators of oxidative stress via endothelial nitric oxide synthase (eNOS) and silent mating-type information regulation 2 homolog (SIRT1). While the exact mechanisms remain unclear, their benefits are likely to include antioxidant and anti-inflammatory effects, notably reducing the susceptibility of low-density lipoproteins to oxidation. Additionally, the interactions between organs under hypoxia signalling underscore the need for a comprehensive regulatory framework that can support the identification of therapeutic targets, advance clinical research, and enhance treatments, including FDA-approved drugs and those in clinical trials. Promising natural products, including polysaccharides, alkaloids, saponins, flavonoids, and peptides, as well as traditional Indian medicines, have demonstrated anti-hypoxic properties. Their mechanisms of action include increasing haemoglobin, glycogen, and ATP levels, reducing oxidative stress and lipid peroxidation, preserving mitochondrial function, and regulating genes related to apoptosis. These findings emphasise the importance of anti-hypoxia research for the development of effective therapies to combat this critical health problem. A recent approach to controlling CVDs involves the use of antioxidant and anti-inflammatory therapeutics through low-dose dietary supplementation. Despite their effectiveness at low doses, further research on ROS, antioxidants, and nutrition, supported by large multicentre trials, is needed to optimize this strategy. Full article

Acute exposure to hypoxia will induce right ventricular (RV) hemodynamic changes and may increase the degree of right-to-left shunting, which can contribute to dyspnea at altitude. In this retrospective study, 125 patients (median age 66 years; 50.4% women) with unexplained dyspnea at altitude underwent hypoxic simulation testing (HST) with transthoracic echocardiography (TTE). During simulated hypoxia (mode (Min-Max) altitude: 8000 (6000–18,000) ft, were observed a significant decrease in oxygen saturation (97% (95–98) vs. 88% (82–92), p < 0.001) and RV free wall longitudinal strain (−19.6 ± 3.99% vs. −17.3 ± 4.17%, p < 0.01), an increase in RV systolic pressure (RVSP: 26 (23–30.5) vs. 29 (25–36.5) mmHg, p < 0.001). No significant changes were observed in TAPSE (20 (18–23) vs. 20 (19–24) mm) or S wave (0.12 (0.11–0.14) vs. 0.13 (0.12–0.14) m/s). Right-to-left shunting was present in 47.2% of patients and 11.9% exhibited inducible shunting only under hypoxia. However, under hypoxia, there were no significant differences in RV hemodynamic parameters or saturation between those with and without shunting. TTE with HST is useful to characterize both cardiopulmonary response and the dynamic changes in right-to-left shunt behavior under hypoxic stress. Full article

Despite significant progress in preclinical research aimed at developing effective therapies for the acute and long-term consequences of perinatal asphyxia, there is still a lack of clinical protocols to regenerate the neonatal brain damaged by hypoxic-ischemic (HI) injury. To date, only therapeutic hypothermia is routinely used in neonates who have experienced perinatal asphyxia. It has been shown to be effective only in limiting the spread of brain damage caused by a cascade of molecular and biochemical events triggered by limited blood supply to the body’s organs, including the fragile, developing brain. Ongoing clinical trials are exploring pharmacological approaches aimed at promoting neurogenesis and gliogenesis to repair damaged neural tissue, as well as modulating the neuroinflammation that results from the cellular response to HI injury. Among promising therapeutic agents, erythropoietin, and melatonin have emerged as major drugs with potential neuroprotective effects in neonatal hypoxic-ischemic encephalopathy. Erythropoietin is recognized for its anti-apoptotic, anti-oxidative, and anti-inflammatory properties, supporting neural cell survival and regeneration. Melatonin acts as a potent antioxidant and anti-inflammatory agent, helping to reduce oxidative stress and inflammation triggered by HI injury. As clinical trials on suffering neonates are highly demanding, the ethical and practical concerns of therapeutic approaches are discussed. An urgent need to develop a safe, feasible, and effective clinical approach to promote the restoration of appropriate neurodevelopment in the near future is highlighted. This review summarizes the clinical trials conducted to date, discusses their outcomes and limitations, and considers translational potential of the tested treatment strategies. Full article

Reduced oxygen availability, or hypoxia, is an environmental stress factor that modulates cellular and systemic functions. It plays a significant role in both physiological and pathological conditions, including tissue regeneration, where it influences angiogenesis, metabolic adaptation, inflammation, and stem cell activity. Hypoxia-inducible factors (HIFs) orchestrate these responses by activating genes that promote survival and repair, although HIF-independent mechanisms, particularly those related to mitochondrial function, are also involved. Depending on its duration and severity, hypoxia may exert either beneficial or harmful effects, ranging from enhanced regeneration to fibrosis or maladaptive remodeling. This review explores the systemic and cellular effects of acute, chronic, intermittent, and preconditioning hypoxia in the context of tissue regeneration. Hypoxia-driven responses are examined across tissues, organs, and complex structures, including the heart, muscle, bone, vascular structures, nervous tissue, and appendages such as tails. We analyze findings from animal models and in vitro studies, followed by biomedical and pharmacological strategies designed to modulate hypoxia and their initial exploration in clinical settings. These strategies involve regulatory molecules, signaling pathways, and microRNA activity, which are investigated across species with diverse regenerative capacities to identify mechanisms that may be conserved or divergent among taxa. Lastly, we emphasize the need to standardize hypoxic conditions to improve reproducibility and highlight their therapeutic potential when precisely controlled. Full article

Hypoxic stress is increasingly recognized as a convergent pathological factor in various age-related neurodegenerative diseases (NDDs), encompassing both acute events such as stroke and traumatic brain injury (TBI), and chronic disorders including Parkinson’s disease (PD), Alzheimer’s disease (AD), and amyotrophic lateral sclerosis (ALS). Recent studies have revealed that hemoglobin (Hb), beyond its classical oxygen-transport function, exhibits unexpected expression and functional relevance within the central nervous system. Notably, both cerebral and circulating Hb appear to be dysregulated under hypoxic and aging conditions, potentially influencing disease onset and progression of these diseases. However, Hb’s impact on neurodegeneration appears to be context-dependent: in acute NDDs, it may exert neuroprotective effects by stabilizing mitochondrial and iron homeostasis, whereas in chronic NDDs, aberrant Hb accumulation may contribute to toxic protein aggregation and neuronal dysfunction. This review provides an integrative overview of the emerging roles of Hb in hypoxia-related NDDs, highlighting both shared and distinct mechanisms across acute and chronic conditions. We further discuss potential therapeutic implications of targeting Hb-related pathways in NDDs and identify key gaps for future investigation. Full article

Objectives: Saffron, a traditional Chinese medicine, is renowned for its pharmacological effects in promoting blood circulation, resolving blood stasis, regulating menstruation, detoxification, and alleviating mental disturbances. Trans-crocetin, its principal bioactive component, exhibits significant anti-hypoxic activity. The clinical development and therapeutic efficacy of trans-crocetin are limited by its instability, poor solubility, and low bioavailability. Conversion of trans-crocetin into trans-sodium crocetinate (TSC) enhances its solubility, stability, and bioavailability, thereby amplifying its anti-hypoxic potential. Methods: This study integrates network pharmacology with in vivo and in vitro validation to elucidate the molecular targets and mechanisms underlying TSC’s therapeutic effects against high-altitude acute lung injury (HALI), aiming to identify novel treatment strategies. Results: TSC effectively reversed hypoxia-induced biochemical abnormalities, ameliorated lung histopathological damage, and suppressed systemic inflammation and oxidative stress in HALI rats. In vitro, TSC mitigated CoCl₂-induced hypoxia injury in human pulmonary microvascular endothelial cells (HPMECs) by reducing inflammatory cytokines, oxidative stress, and ROS accumulation while restoring mitochondrial membrane potential. Network pharmacology and pathway analysis revealed that TSC primarily targets the EGFR/PI3K/AKT/NF-κB signaling axis. Molecular docking and dynamics simulations demonstrated stable binding interactions between TSC and key components of this pathway. ELISA and RT-qPCR confirmed that TSC significantly downregulated the expression of EGFR, PI3K, AKT, NF-κB, and their associated mRNAs. Conclusions: TSC alleviates high-altitude hypoxia-induced lung injury by inhibiting the EGFR/PI3K/AKT/NF-κB signaling pathway, thereby attenuating inflammatory responses, oxidative stress, and restoring mitochondrial function. These findings highlight TSC as a promising therapeutic agent for HALI. Full article

Rapid ascent to high altitudes by unacclimatized individuals significantly increases the risk of brain damage, given the brain’s heightened sensitivity to hypoxic conditions. Investigating hypoxia-tolerant animals can provide insights into adaptive mechanisms and guide prevention and treatment of hypoxic-ischemic brain injury. In this study, we exposed Brandt’s voles to simulated altitudes (100 m, 3000 m, 5000 m, and 7000 m) for 24 h and performed quantitative proteomic and phosphoproteomic analyses of brain tissue. A total of 3990 proteins and 9125 phosphorylation sites (phospho-sites) were quantified. Differentially expressed (DE) analysis revealed that while protein abundance changes were relatively modest, phosphorylation levels exhibited substantial alterations, suggesting that Brandt’s voles rapidly regulate protein structure and function through phosphorylation to maintain cellular homeostasis under acute hypoxia. Clustering analysis showed that most co-expressed proteins exhibited non-monotonic responses with increasing altitude, which were enriched in pathways related to cytokine secretion regulation and glutathione metabolism, contributing to reduced inflammation and oxidative stress. In contrast, most co-expressed phospho-sites showed monotonic changes, with phospho-proteins enriched in glycolysis and vascular smooth muscle contraction regulation. Kinase activity prediction identified nine hypoxia-responsive kinases, four of which belonging to the CAMK family. Immunoblot validated that the changes in CAMK2A activity were consistent with predictions, suggesting that CAMK may play a crucial role in hypoxic response. In conclusion, this work discovered that Brandt’s voles may cope with hypoxia through three key strategies: (1) vascular regulation to enhance cerebral blood flow, (2) glycolytic activation to increase energy production, and (3) activation of neuroprotective mechanisms. Full article

CD133+CD24+ renal tubular progenitor cells play a crucial role in the repair and regeneration of renal tubules after acute kidney injury. The aim of this study is to investigate the responses of the human renal tubular precursor TERT (HRTPT) CD133+CD24+ cells and human renal epithelial cell 24 TERT (HREC24T) CD133-CD24+ cells to hypoxic stress, as well as their gene expression profiles. Whole transcriptome sequencing and functional network analysis identified distinct molecular characteristics of HRTPT cells as they were enriched with hypoxia-inducible factor-1A (HIF1A), epidermal growth factor (EGF), and endothelin-1 (EDN1). Our in vitro experiments demonstrated that, under hypoxia (2.5% oxygen), HRTPT cells showed minimal cell death and a 100-fold increase in HIF1A protein levels. In contrast, HREC24T cells exhibited significant cell death and only a two-fold increase in HIF1A protein level. These results indicate that CD133+CD24+ renal tubular progenitor cells have enhanced survival mechanisms under hypoxic stress, enabling them to survive and proliferate to replace damaged tubular cells. This study provides novel insights into the protective role of CD133+CD24+ renal tubular progenitor cells in hypoxic renal injury and identifies their potential survival mechanisms. Full article

This study aimed to investigate the protective effects of ginsenoside Rg1 on high-altitude hypoxia-induced acute lung injury (ALI) and elucidated its molecular targets and related pathways, specifically its association with the fluid shear stress pathway. Using a combination of bioinformatics analysis and both in vivo and in vitro experiments, we assessed the role of ginsenoside Rg1 in mitigating physiological and biochemical disturbances induced by hypoxia. In the in vivo experiments, we measured arterial blood gas parameters, levels of inflammatory cells and cytokines, erythrocyte and platelet parameters, and conducted histological analysis in rats. The in vitro experiments utilized human pulmonary microvascular endothelial cells (HPMECs) and A549 cells to examine cell viability, intracellular reactive oxygen species (ROS) and Ca²⁺ levels, and mitochondrial function. The results of the in vivo experiments demonstrate that ginsenoside Rg1 significantly increased arterial blood oxygen partial pressure and saturation, elevated arterial blood glucose levels, and stabilized respiratory and metabolic functions in rats. It also reduced inflammatory cells and cytokines, such as tumor necrosis factor-α and interleukin-6, and improved erythrocyte and platelet abnormalities, supporting its protective role through the regulation of the fluid shear stress pathway. Histological and ultrastructural analyses revealed that Rg1 significantly protected lung tissue structure and organelles. In vitro experiments further confirmed that Rg1 improved cell viability in HPMEC and A549 cells under hypoxic conditions, decreased intracellular ROS and Ca²⁺ levels, and enhanced mitochondrial function. These findings collectively demonstrate that ginsenoside Rg1 exerts significant protective effects against high-altitude hypoxia-induced ALI by enhancing oxygen delivery and utilization, reducing inflammatory responses, and maintaining cellular metabolism and vascular function. Notably, the protective effects of Rg1 are closely associated with the regulation of the fluid shear stress pathway, suggesting its potential for treating high-altitude hypoxia-related diseases. Full article

Perinatal asphyxia refers to an acute event of cerebral ischemia and hypoxia during the perinatal period, leading to various degrees of brain injury. The mechanisms involved in perinatal asphyxia include the production of reactive oxygen species (ROS), accumulation of intracellular calcium, lipid peroxidation, excitatory amino acid receptor overactivation, energy failure, and caspase-mediated cell death. Both primary and secondary neuronal damage are caused by the overproduction of ROS following a hypoxic/ischemic event. ROS can react with nearly any type of molecule, including lipids, proteins, polysaccharides, and DNA. Neonates who suffer from perinatal asphyxia are prone to oxidative stress, which is characterized by a disruption in the oxidant/antioxidant balance, favoring oxidants over the intracellular and extracellular antioxidant scavenging mechanisms. Current research has focused on developing treatment strategies that potentially improve the endogenous antioxidant neuroprotective mechanisms or minimize injury resulting from hypoxia/ischemia. In this narrative review, we aim to present evidence regarding the contribution of oxidant/antioxidant balance to the pathogenesis and progression of perinatal asphyxia. Also, we aim to explore the role of potential antioxidant therapies as promising treatment strategies for perinatal asphyxia, especially as an adjunct to therapeutic hypothermia in infants with perinatal asphyxia. The current literature on antioxidant treatments in newborns is limited; however, allopurinol, melatonin, and erythropoietin have shown some positive effects in clinical trials. Inhibitors of nitric oxide synthase, N-acetylcysteine, and docosahexaenoic acid have shown promising neuroprotective effects in preclinical studies. Finally, nanotherapeutics could potentially modulate oxidative stress in hypoxemic/ischemic brain injury by targeted medication delivery. Future research on neuroprotectants and their processes is warranted to develop innovative treatments for hypoxia/ischemia in clinical practice. Full article

Hydrogen sulfide (H₂S), as a key gas signaling molecule, plays an important role in regulating various diseases, with appropriate concentrations providing antioxidative, anti-inflammatory, and anti-apoptotic effects. The specific role of H₂S in acute hypoxic injury remains to be clarified. This study focuses on the H₂S donor sodium hydrosulfide (NaHS) and explores its protective effects and mechanisms against acute hypoxic lung injury. First, various mouse hypoxia models were established to evaluate H₂S’s protection in hypoxia tolerance. Next, a rat model of acute lung injury (ALI) induced by hypoxia at 6500 m above sea level for 72 h was created to assess H₂S’s protective effects and mechanisms. Evaluation metrics included blood gas analysis, blood routine indicators, lung water content, and lung tissue pathology. Additionally, LC-MS/MS and bioinformatic analyses were combined in performing quantitative proteomics on lung tissues from the normoxic control group, the hypoxia model group, and the hypoxia model group with NaHS treatment to preliminarily explore the protective mechanisms of H₂S. Further, enzyme-linked immunosorbent assays (ELISA) were used to measure oxidative stress markers and inflammatory factors in rat lung tissues. Lastly, Western blot analysis was performed to detect Nrf2, HO-1, P-NF-κB, NF-κB, HIF-1α, Bcl-2, and Bax proteins in lung tissues. Results showed that H₂S exhibited significant anti-hypoxic effects in various hypoxia models, effectively modulating blood gas and blood routine indicators in ALI rats, reducing pulmonary edema, improving lung tissue pathology, and alleviating oxidative stress, inflammatory responses, and apoptosis levels. Full article

Acute myocardial infarction (MI) is a sudden, severe cardiac ischemic event that results in the death of up to one billion cardiomyocytes (CMs) and subsequent decrease in cardiac function. Engineered cardiac tissues (ECTs) are a promising approach to deliver the necessary mass of CMs to remuscularize the heart. However, the hypoxic environment of the heart post-MI presents a critical challenge for CM engraftment. Here, we present a high-throughput, systematic study targeting several physiological features of human induced pluripotent stem cell-derived CMs (hiPSC-CMs), including metabolism, Wnt signaling, substrate, heat shock, apoptosis, and mitochondrial stabilization, to assess their efficacy in promoting ischemia resistance in hiPSC-CMs. The results of 2D experiments identify hypoxia preconditioning (HPC) and metabolic conditioning as having a significant influence on hiPSC-CM function in normoxia and hypoxia. Within 3D engineered cardiac tissues (ECTs), metabolic conditioning with maturation media (MM), featuring high fatty acid and calcium concentration, results in a 1.5-fold increase in active stress generation as compared to RPMI/B27 control ECTs in normoxic conditions. Yet, this functional improvement is lost after hypoxia treatment. Interestingly, HPC can partially rescue the function of MM-treated ECTs after hypoxia. Our systematic and iterative approach provides a strong foundation for assessing and leveraging in vitro culture conditions to enhance the hypoxia resistance, and thus the successful clinical translation, of hiPSC-CMs in cardiac regenerative therapies. Full article

Crocetin is an aglycone of crocin naturally occurring in saffron and has been proved to have antioxidant, anti-inflammatory, and antibacterial activities. In this experiment, the protective effect of crocetin on vital organs in high-altitude hypoxia rats was studied. Crocetin was prepared from gardenia by the alkaline hydrolysis method, and its reducing ability and free radical scavenging ability were tested. The in vitro anti-hypoxia vitality was studied on PC₁₂ cells. The anti-hypoxic survival time of mice was determined in several models. The acute hypoxic injury rat model was established by simulating the hypoxic environment of 8000 m-high altitude for 24 h, and the anti-hypoxia effect of crocetin was evaluated by intraperitoneal injection with the doses of 10, 20, and 40 mg/kg. The water contents of the brain and lung were determined, and the pathological sections in the brain, lung, heart, liver, and kidney were observed by HE staining. The levels of oxidative stress (SOD, CAT, H₂O₂, GSH, GSH-Px, MDA) and inflammatory factors (IL-1β, IL-6, TNF-α, VEGF) in rat brain, lung, heart, liver, and kidney tissues were detected by ELISA. The results indicated that crocetin exhibited strong reducing ability and free radical scavenging ability and could improve the activity of PC₁₂ cells under hypoxia. After intraperitoneal injection with crocetin, the survival time of mice was prolonged, and the pathological damage, oxidative stress, and inflammation in rats’ tissue were ameliorated. The protective activity of crocetin on vital organs in high-altitude hypoxia rats may be related to reducing oxidative stress and inhibiting inflammatory response. Full article

Ischemia/reperfusion injury (IRI) represents a significant contributor to morbidity and mortality associated with various clinical conditions, including acute coronary syndrome, stroke, and organ transplantation. During ischemia, a profound hypoxic insult develops, resulting in cellular dysfunction and tissue damage. Paradoxically, reperfusion can exacerbate this injury through the generation of reactive oxygen species and the induction of inflammatory cascades. The extensive clinical sequelae of IRI necessitate the development of therapeutic strategies to mitigate its deleterious effects. This has become a cornerstone of ongoing research efforts in both basic and translational science. This review examines the use of molecular hydrogen for IRI in different organs and explores the underlying mechanisms of its action. Molecular hydrogen is a selective antioxidant with anti-inflammatory, cytoprotective, and signal-modulatory properties. It has been shown to be effective at mitigating IRI in different models, including heart failure, cerebral stroke, transplantation, and surgical interventions. Hydrogen reduces IRI via different mechanisms, like the suppression of oxidative stress and inflammation, the enhancement of ATP production, decreasing calcium overload, regulating cell death, etc. Further research is still needed to integrate the use of molecular hydrogen into clinical practice. Full article