Malarial infection induces tissue hypoxia in the host through destruction of red blood cells. Tissue hypoxia in malarial infection may increase the activity of HIF1α through an intracellular oxygen-sensing pathway. Activation of HIF1α may also induce vascular endothelial growth factor (VEGF) to trigger angiogenesis. To investigate whether malarial infection actually generates hypoxia-induced angiogenesis, we analyzed severity of hypoxia, the expression of hypoxia-related angiogenic factors, and numbers of blood vessels in various tissues infected with Plasmodium berghei. Infection in mice was performed by intraperitoneal injection of 2×10⁶ parasitized red blood cells. After infection, we studied parasitemia and survival. We analyzed hypoxia, numbers of blood vessels, and expression of hypoxia-related angiogenic factors including VEGF and HIF1α. We used Western blot, immunofluorescence, and immunohistochemistry to analyze various tissues from Plasmodium berghei-infected mice. In malaria-infected mice, parasitemia was increased over the duration of infection and directly associated with mortality rate. Expression of VEGF and HIF1α increased with the parasitemia in various tissues. Additionally, numbers of blood vessels significantly increased in each tissue type of the malaria-infected group compared to the uninfected control group. These results suggest that malarial infection in mice activates hypoxia-induced angiogenesis by stimulation of HIF1α and VEGF in various tissues.
Angiogenesis Inducing Agents ; Animals ; Anoxia ; Blood Vessels ; Blotting, Western ; Erythrocytes ; Fluorescent Antibody Technique ; Immunohistochemistry ; Injections, Intraperitoneal ; Malaria ; Mice ; Mortality ; Parasitemia ; Plasmodium ; Plasmodium berghei ; Vascular Endothelial Growth Factor A

BACKGROUND: Beyond its current function as a rescue therapy in acute respiratory distress syndrome (ARDS), extracorporeal membrane oxygenation (ECMO) may be applied in ARDS patients with less severe hypoxemia to facilitate lung protective ventilation. The purpose of this study was to evaluate the efficacy of extended ECMO use in ARDS patients. METHODS: This study reviewed 223 adult patients who had been admitted to the intensive care units of 11 hospitals in Korea and subsequently treated using ECMO. Among them, the 62 who required ECMO for ARDS were analyzed. The patients were divided into two groups according to pre-ECMO arterial blood gas: an extended group (n=14) and a conventional group (n=48). RESULTS: Baseline characteristics were not different between the groups. The median arterial carbon dioxide tension/fraction of inspired oxygen (FiO2) ratio was higher (97 vs. 61, p<0.001) while the median FiO2 was lower (0.8 vs. 1.0, p<0.001) in the extended compared to the conventional group. The 60-day mortality was 21% in the extended group and 54% in the conventional group (p=0.03). Multivariate analysis indicated that the extended use of ECMO was independently associated with reduced 60-day mortality (odds ratio, 0.10; 95% confidence interval, 0.02–0.64; p=0.02). Lower median peak inspiratory pressure and median dynamic driving pressure were observed in the extended group 24 hours after ECMO support. CONCLUSION: Extended indications of ECMO implementation coupled with protective ventilator settings may improve the clinical outcome of patients with ARDS.
Adult ; Anoxia ; Carbon Dioxide ; Extracorporeal Membrane Oxygenation ; Humans ; Intensive Care Units ; Korea ; Lung ; Mortality ; Multicenter Studies as Topic ; Multivariate Analysis ; Oxygen ; Respiration, Artificial ; Respiratory Distress Syndrome, Adult ; Retrospective Studies ; Ventilation ; Ventilators, Mechanical

PURPOSE: The aim of this study was to investigate whether propofol could attenuate hypoxia/reoxygenation-induced apoptosis and autophagy in human renal proximal tubular cells (HK-2) by inhibiting JNK activation. MATERIALS AND METHODS: HK-2 cells were treated with or without propofol or JNK inhibitor SP600125 for 1 hour and then subjected to 15 hours of hypoxia and 2 hours of reoxygenation (H/R). Cell viability and LDH release were measured with commercial kits. Cell apoptosis was evaluated by flow cytometry. The expressions of p-JNK, cleaved-caspase-3, Bcl-2, and autophagy markers LC3 and p62 were measured by Western blot or immunofluorescence. RESULTS: HK-2 cells exposed to H/R insult showed higher cell injury (detected by increased LDH release and decreased cell viability), increased cell apoptosis index and expression of cleaved-caspase-3, a decrease in the expression of Bcl-2 accompanied by increased expression of p-JNK and LC3II, and a decrease in expression of p62. All of these alterations were attenuated by propofol treatment. Similar effects were provoked upon treatment with the JNK inhibitor SP600125. Moreover, the protective effects were more obvious with the combination of propofol and SP600125. CONCLUSION: These results suggest that propofol could attenuate hypoxia/reoxygenation induced apoptosis and autophagy in HK-2 cells, probably through inhibiting JNK activation.
Anoxia ; Apoptosis ; Autophagy ; Blotting, Western ; Cell Survival ; Flow Cytometry ; Fluorescent Antibody Technique ; Humans ; Propofol

PURPOSE: Hepatocellular carcinoma (HCC) is a common cancer worldwide. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a long noncoding RNA (lncRNA), has been reported to be aberrantly expressed in hypoxic cancer cells. MALAT1 plays a significant role in many malignancies, including HCC. The aim of this study was to explore the role of MALAT1 in hypoxic HCC cells and its underlying regulatory mechanism. MATERIALS AND METHODS: Quantitative reverse transcription PCR (qRT-PCR) assay was performed to detect the mRNA levels of MALAT1 and microRNA-200a (miR-200a) in HCC cells. Cell invasion and migration ability were evaluated by Transwell assay. Starbase v2.0 and luciferase reporter assay were employed to identify the association between MALAT1 and miR-200a. Cell proliferation and apoptosis were measured by MTT assay and flow cytometry, respectively. RESULTS: MALAT1 levels were significantly upregulated in HCC cells under hypoxia. Hypoxia promoted proliferation, migration, and invasion, and blocked apoptosis in Hep3B cells, which were weakened by knockdown of MALAT1. Starbase v2.0 showed that MALAT1 and miR-200a have a complementarity region, and luciferase reporter assay verified that MALAT1 interacted with miR-200a in Hep3B cells. Moreover, MALAT1 negatively regulated the expression of miR-200a. miR-200a levels were dramatically downregulated in HCC cells under hypoxia. Upregulation of miR-200a inhibited proliferation, migration, and invasion, and induced apoptosis in Hep3B cells under hypoxia. Interestingly, downregulation of miR-200a partially reversed the tumor-suppressive effect of knockdown of MALAT1 on Hep3B cells in hypoxic condition. CONCLUSION: LncRNA MALAT1 was involved in proliferation, migration, invasion, and apoptosis by interacting with miR-200a in hypoxic Hep3B cells, revealing a new mechanism of MALAT1 involved in hypoxic HCC progression.
Adenocarcinoma ; Anoxia ; Apoptosis ; Carcinoma, Hepatocellular ; Cell Proliferation ; Down-Regulation ; Flow Cytometry ; Luciferases ; Lung ; Polymerase Chain Reaction ; Reverse Transcription ; RNA, Long Noncoding ; RNA, Messenger ; Up-Regulation

BACKGROUND: Face transplantation has naturally evolved from reconstructive procedures. However, few institutions perform face transplantations, because it is time-consuming and it is necessary to justify non-vital organ transplantation. We investigated the process of organ donation from brain-dead patients and the possibility of incorporating face transplantation into the donation process. METHODS: A retrospective review was performed of 1,074 brain-dead patients from January 2015 to December 2016 in Korea. We analyzed the time intervals from admission to brain death decisions (first, second, and final), the causes of brain death, and the state of the transplanted organs. RESULTS: The patient base (n=1,074) was composed of 747 males and 327 females. The average period between admission to the first brain death decision was 8.5 days (±15.3). The average time intervals between the first brain death decision and medical confirmation using electroencephalography and between the first brain death decision and the final determination of brain death were 16 hours 58 minutes (±14 hours 50 minutes) and 22 hours 57 minutes (±16 hours 16 minutes), respectively. The most common cause of brain death was cerebral hemorrhage/stroke (42.3%), followed by hypoxia (30.1%), and head trauma (25.2%). CONCLUSIONS: When face transplantation is performed, the transplantation team has 22 hours 57 minutes on average to prepare after the first brain death decision. The cause of brain death was head trauma in approximately one-fourth of cases. Although head trauma does not always imply facial trauma, surgeons should be aware that the facial tissue may be compromised in such cases.
Anoxia ; Brain Death ; Brain ; Craniocerebral Trauma ; Electroencephalography ; Facial Transplantation ; Female ; Humans ; Korea ; Male ; Organ Transplantation ; Retrospective Studies ; Surgeons ; Tissue and Organ Procurement ; Tissue Donors ; Transplantation ; Transplants

OBJECTIVE: Hypoxic-ischemic (HI) brain injury in the human perinatal period often leads to significant long-term neurobehavioral dysfunction in the cognitive and sensory-motor domains. Using a neonatal HI injury model (unilateral carotid ligation followed by hypoxia) in postnatal day seven rats, the present study investigated the long-term effects of HI and potential behavioral protective effect of pentoxifylline. METHODS: Seven-day-old rats underwent right carotid ligation, followed by hypoxia (FiO2 = 0.08). Rats received pentoxifylline immediately after and again 2 hours after hypoxia (two doses, 60–100 mg/kg/dose), or serum physiologic. Another set of seven-day-old rats was included to sham group exposed to surgical stress but not ligated. These rats were tested for spatial learning and memory on the simple place task in the Morris water maze from postnatal days 77 to 85. RESULTS: HI rats displayed significant tissue loss in the right hippocampus, as well as severe spatial memory deficits. Low-dose treatment with pentoxifylline resulted in significant protection against both HI-induced hippocampus tissue losses and spatial memory impairments. Beneficial effects are, however, negated if pentoxifylline is administered at high dose. CONCLUSION: These findings indicate that unilateral HI brain injury in a neonatal rodent model is associated with cognitive deficits, and that low dose pentoxifylline treatment is protective against spatial memory impairment.
Animals ; Anoxia ; Brain Injuries ; Brain ; Cognition Disorders ; Hippocampus ; Humans ; Hypoxia-Ischemia, Brain ; Learning ; Ligation ; Memory ; Pentoxifylline ; Rats ; Rodentia ; Spatial Learning ; Spatial Memory ; Water

Adipose tissue inflammation is considered a major contributing factor in the development of obesity-associated insulin resistance and cardiovascular diseases. However, the cause of adipose tissue inflammation is presently unclear. The role of mitochondria in white adipocytes has long been neglected because of their low abundance. However, recent evidence suggests that mitochondria are essential for maintaining metabolic homeostasis in white adipocytes. In a series of recent studies, we found that mitochondrial function in white adipocytes is essential to the synthesis of adiponectin, which is the most abundant adipokine synthesized from adipocytes, with many favorable effects on metabolism, including improvement of insulin sensitivity and reduction of atherosclerotic processes and systemic inflammation. From these results, we propose a new hypothesis that mitochondrial dysfunction in adipocytes is a primary cause of adipose tissue inflammation and compared this hypothesis with a prevailing concept that “adipose tissue hypoxia” may underlie adipose tissue dysfunction in obesity. Recent studies have emphasized the role of the mitochondrial quality control mechanism in maintaining mitochondrial function. Future studies are warranted to test whether an inadequate mitochondrial quality control mechanism is responsible for mitochondrial dysfunction in adipocytes and adipose tissue inflammation.
11-beta-Hydroxysteroid Dehydrogenases ; Adipocytes ; Adipocytes, White ; Adipokines ; Adiponectin ; Adipose Tissue ; Anoxia ; Cardiovascular Diseases ; Homeostasis ; Inflammation ; Insulin Resistance ; Metabolism ; Mitochondria ; Nitric Oxide ; Obesity ; Quality Control

BACKGROUND: The relationship between obstructive sleep apnoea (OSA) and metabolic disorders is complex and highly associated. The impairment of adipogenic capacity in pre-adipocytes may promote adipocyte hypertrophy and increase the risk of further metabolic dysfunction. We hypothesize that intermittent hypoxia (IH), as a pathophysiologic feature of OSA, may regulate adipogenesis by promoting macrophage polarization. METHODS: Male C57BL/6N mice were exposed to either IH (240 seconds of 10% O₂ followed by 120 seconds of 21% O₂, i.e., 10 cycles/hour) or intermittent normoxia (IN) for 6 weeks. Stromal-vascular fractions derived from subcutaneous (SUB-SVF) and visceral (VIS-SVF) adipose tissues were cultured and differentiated. Conditioned media from cultured RAW 264.7 macrophages after air (Raw) or IH exposure (Raw-IH) were incubated with SUB-SVF during adipogenic differentiation. RESULTS: Adipogenic differentiation of SUB-SVF but not VIS-SVF from IH-exposed mice was significantly downregulated in comparison with that derived from IN-exposed mice. IH-exposed mice compared to IN-exposed mice showed induction of hypertrophic adipocytes and increased preferential infiltration of M1 macrophages in subcutaneous adipose tissue (SAT) compared to visceral adipose tissue. Complementary in vitro analysis demonstrated that Raw-IH media significantly enhanced inhibition of adipogenesis of SUB-SVF compared to Raw media, in agreement with corresponding gene expression levels of differentiation-associated markers and adipogenic transcription factors. CONCLUSION: Low frequency IH exposure impaired adipogenesis of SAT in lean mice, and macrophage polarization may be a potential mechanism for the impaired adipogenesis.
Adipocytes ; Adipogenesis ; Animals ; Anoxia ; Culture Media, Conditioned ; Gene Expression ; Humans ; Hypertrophy ; In Vitro Techniques ; Inflammation ; Intra-Abdominal Fat ; Macrophages ; Male ; Mice ; Subcutaneous Fat ; Transcription Factors

Hypoxia-inducible factor 1 (HIF1) is a master transcription factor that induces the transcription of genes involved in the metabolism and behavior of stem cells. HIF1-mediated adaptation to hypoxia is required to maintain the pluripotency and survival of stem cells under hypoxic conditions. HIF1 activity is well known to be tightly controlled by the alpha subunit of HIF1 (HIF1α). Understanding the regulatory mechanisms that control HIF1 activity in stem cells will provide novel insights into stem cell biology under hypoxia. Recent research has unraveled the mechanistic details of HIF1α regulating processes, suggesting new strategies for regulating stem cells. This review summarizes recent experimental studies on the role of several regulatory factors (including calcium, 2-oxoglutarate-dependent dioxygenase, microtubule network, importin, and coactivators) in regulating HIF1α activity in stem cells.
Anoxia ; Biology ; Calcium ; Hypoxia-Inducible Factor 1 ; Karyopherins ; Metabolism ; Microtubules ; Stem Cells ; Transcription Factors

BACKGROUND AND OBJECTIVES: There have been contradictory reports on the pro-cancer or anti-cancer effects of mesenchymal stem cells. In this study, we investigated whether conditioned medium (CM) from hypoxic human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) (H-CM) showed enhanced anti-cancer effects compared with CM from normoxic hUC-MSCs (N-CM). METHODS AND RESULTS: Compared with N-CM, H-CM not only strongly reduced cell viability and increased apoptosis of human cervical cancer cells (HeLa cells), but also increased caspase-3/7 activity, decreased mitochondrial membrane potential (MMP), and induced cell cycle arrest. In contrast, cell viability, apoptosis, MMP, and cell cycle of human dermal fibroblast (hDFs) were not significantly changed by either CM whereas caspase-3/7 activity was decreased by H-CM. Protein antibody array showed that activin A, Beta IG-H3, TIMP-2, RET, and IGFBP-3 were upregulated in H-CM compared with N-CM. Intracellular proteins that were upregulated by H-CM in HeLa cells were represented by apoptosis and cell cycle arrest terms of biological processes of Gene Ontology (GO), and by cell cycle of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. In hDFs, negative regulation of apoptosis in biological process of GO and PI3K-Akt signaling pathway of KEGG pathways were represented. CONCLUSIONS: H-CM showed enhanced anti-cancer effects on HeLa cells but did not influence cell viability or apoptosis of hDFs and these different effects were supported by profiling of secretory proteins in both kinds of CM and intracellular signaling of HeLa cells and hDFs.
Activins ; Anoxia ; Apoptosis ; Biological Processes ; Cell Cycle ; Cell Cycle Checkpoints ; Cell Survival ; Culture Media, Conditioned ; Fibroblasts ; Gene Ontology ; Genome ; HeLa Cells ; Humans ; Insulin-Like Growth Factor Binding Protein 3 ; Membrane Potential, Mitochondrial ; Mesenchymal Stromal Cells ; Tissue Inhibitor of Metalloproteinase-2 ; Uterine Cervical Neoplasms