ApTOLL: A new therapeutic aptamer for cytoprotection and (re)myelination after multiple sclerosis.

BACKGROUND AND PURPOSE: ApTOLL is an aptamer selected to antagonize toll-like receptor 4 (TLR4), a relevant actor for innate immunity involved in inflammatory responses in multiple sclerosis (MS) and other diseases. The currently available therapeutic arsenal to treat MS is composed of immunomodulators but, to date, there are no (re)myelinating drugs available in clinics. In our present study, we studied the effect of ApTOLL on different animal models of MS. EXPERIMENTAL APPROACH: The experimental autoimmune encephalomyelitis (EAE) model was used to evaluate the effect of ApTOLL on reducing the inflammatory component. A more direct effect on oligodendroglia was studied with the cuprizone model and purified primary cultures of murine and human oligodendrocyte precursor cells (OPCs) isolated through magnetic-activated cell sorting (MACS) from samples of brain cortex. Also, we tested these effects in an ex vivo model of organotypic cultures demyelinated with lysolecithin (LPC). KEY RESULTS: ApTOLL treatment positively impacted the clinical symptomatology of mice in the EAE and cuprizone models, which was associated with better preservation plus restoration of myelin and oligodendrocytes in the demyelinated lesions of animals. Restoration was corroborated on purified cultures of rodent and human OPCs. CONCLUSION AND IMPLICATIONS: Our findings reveal a new therapeutic approach for the treatment of inflammatory and demyelinating diseases such as MS. The molecular nature of the aptamer exerts not only an anti-inflammatory effect but also neuroprotective and remyelinating effects. The excellent safety profile demonstrated by ApTOLL in animals and humans opens the door to future clinical trials in MS patients.

Carbon dots decorated magnetite nanocomposite obtained using yerba mate useful for remediation of textile wastewater through a photo-Fenton treatment: Ilex paraguariensis as a platform of environmental interest-part 2.

Two carbon dots (CD) with diameters of 4.9 ± 1.5 and 4.1 ± 1.2 nm were successfully synthesized through an acid ablation route with HNO3 or H2SO4, respectively, using Ilex paraguariensis as raw material. The CD were used to produce magnetite-containing nanocomposites through two different routes: hydrothermal and in situ. A thorough characterization of the particles by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), dynamic light scattering (DLS), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) indicates that all nanomaterials have spherical-like morphology with a core-shell structure. The composition of this structure depends on the route used: with the hydrothermal route, the shell is composed of the CD, but with the in situ process, the CD act as nucleation centers, and so the iron oxide domains are in the shell. Regarding the photocatalytic mechanism for the degradation of methyl orange, the interaction between the CD and the magnetite plays an important role in the photo-Fenton reaction at pH 6.2, in which ligand-to-metal charge transfer processes (LTMCT) allow Fe2+ regeneration. All materials (100 ppm) showed catalytic activity in the elimination of methyl orange (8.5 ppm), achieving discoloration of up to 98% under visible irradiation over 400 nm in 7 h. This opens very interesting possibilities for the use of agro-industrial residues for sustainable synthesis of catalytic nanomaterials, and the role of the interaction of iron-based catalysts with organic matter in heterogeneous Fenton-based processes.

Measurement of stigma and associated characteristics in people with tuberculosis in Medellín, Colombia: a cross-sectional study.

BACKGROUND: Stigma towards tuberculosis (TB) delays diagnosis and compromises adherence to treatment. We measured the degree of stigma and identified the sociodemographic and clinical characteristics that were associated with a higher degree of stigma in patients with pulmonary and extrapulmonary TB in Colombia. METHODS: We conducted a cross-sectional study with 232 participants included in the TB control program in 2017. Sociodemographic and clinical variables were measured. The stigma component was measured through a validated scale and a multiple linear regression was used. RESULTS: The study analysed 232 patients, of which 52.2% were men, 53.5% were between 27 and 59 y of age and 66.8% had a basic-medium education level. Two characteristics were significantly related to a higher stigma score: the basic-medium education level and homeless status. Homeless status increased the stigma score by 0.27. In contrast, the adjusted stigma score decreased by 0.07 if the patient's health status was perceived as 'healthy'. CONCLUSION: Stigma is maximized in homeless patients and patients with a low education level. It is minimized in patients who perceive their state of health as 'healthy'.

Iron oxide nanoparticles embedded in organic microparticles from Yerba Mate useful for remediation of textile wastewater through a photo-Fenton treatment: Ilex paraguariensis as a platform of environmental interest - Part 1.

Seven composites of iron oxide nanoparticles embedded in organic microparticles mediated by Cu(II) were synthesized using yerba mate (Ilex paraguariensis) dry leaf extract as precipitant, capping agent, and dispersant medium, using different Cu/Fe molar ratios. A thorough characterization of the particles by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis-mass spectrometry (TGA-MS), Fourier transform infrared spectrometer (FTIR), and atomic absorption-spectrometry (AA) indicates that all materials have spheric-like morphology with nanoparticles composed by metal oxide phases embedded into organic microparticles. Interestingly, this organic matter is proposed to play an important role in the solids' photocatalytic activity in a photo-Fenton reaction, in which iron photo-leaching was elucidated, and a mechanism through ligand-to-metal charge transfer processes was proposed. All materials showed catalytic activity in the methyl orange elimination, achieving discolorations up to 96% in 2 h under UV irradiation at 375 nm. An experimental correlation between all samples' UV/Vis spectra and their performances for methyl orange discoloration was observed. This process opens a landscape very interesting for the use of agroindustrial residues for green synthesis of metal oxide nanomaterials and their use and understanding of organo-metallic systems participation in Fenton-based processes.

Delays in diagnosing pulmonary tuberculosis within a context of medium incidence, Medellín, Colombia, 2017: an operational research.

BACKGROUND: Delay in tuberculosis (TB) diagnosis is one of the first obstacles for controlling the disease. Delays generate greater deterioration of the health of the patients and increase the possibilities of transmission and infection at home and in the community. The aim of the study was to identify profiles and individual variables associated with patient delays and health care system delays in patients with pulmonary tuberculosis (PTB) in Medellín, Colombia, a city that notifies 1400 new cases per year. METHODS: A retrospective cohort study in adults with PTB was conducted from May to September of 2017. Sociodemographic, health care-seeking behaviour, and clinical variables were measured. The outcomes were patient delay and health care system delay. The data were obtained from records of the local TB program, and a questionnaire was applied by the health care team that performs routine field visits. Simple correspondence analysis was used to identify groups (profiles), and their characteristics. Cox's proportional hazards model was carried out to identify the variables associated with the delays. RESULTS: The study included 183 patients. The total delay median was 101 days (IQR: 64-163). Patient delay was of 35 days (IQR: 14-84), the profile with greater delay belonged to consumers of psychoactive substances. The health care system delay was of 27 days (IQR: 7-89), the attributes of the profile with greater delay were being a female, having more than two consultations before the diagnosis, and having prescribed antibiotics. Basic-medium educational level [HRa = 0.69; 95% CI (0.49-0.97)] and having a TB home contact [HRa = 0.68; 95% CI (0.48-0.96)] were associated with greater patient delay. Having negative acid-fast bacilli (AFB) smear [HRa = 0.64; 95% CI (0.45-0.92)] and more than two consultations before the diagnosis [HRa = 0.33; 95% CI (0.22-0.49)] was associated with greater health care system delay. CONCLUSIONS: Data from epidemiological surveillance allowed locating risk groups with delays in TB diagnosis which requires the prioritisation of the local TB control program to promote early detection and prevention of adverse outcomes.

Bumetanide Suppression of Angiogenesis in a Rat Model of Oxygen-Induced Retinopathy.

Aquaporins (AQPs) are involved in hypoxia-induced angiogenesis and retinal damage. Bumetanide is a diuretic agent, Na+/K+/Cl- cotransporter (NKCC1), and AQP 1-4 inhibitor. We tested the hypothesis that early postnatal treatment with bumetanide suppresses biomarkers of angiogenesis and decreases severe retinopathy oxygen-induced retinopathy (OIR). Neonatal rats were exposed at birth (P0) to either (1) room air (RA); (2) hyperoxia (50% O2); or (3) intermittent hypoxia (IH) consisting of 50% O2 with brief, clustered episodes of 12% O2 from P0 to postnatal day 14 (P14), during which they were treated intraperitoneally (IP) with bumetanide (0.1 mg/kg/day) or an equivalent volume of saline, on P0-P2. Pups were examined at P14 or allowed to recover in RA from P14-P21. Retinal angiogenesis, morphometry, pathology, AQPs, and angiogenesis biomarkers were determined at P14 and P21. Bumetanide reduced vascular abnormalities associated with severe OIR. This was associated with reductions in AQP-4 and VEGF. Bumetanide suppressed sVEGFR-1 in the serum and vitreous fluid, but levels were increased in the ocular tissues during recovery. Similar responses were noted for IGF-I. In this model, early systemic bumetanide administration reduces severe OIR, the benefits of which appear to be mediated via suppression of AQP-4 and VEGF. Further studies are needed to determine whether bumetanide at the right doses may be considered a potential pharmacologic agent to treat retinal neovascularization.

Pharmacologic interventions for the prevention and treatment of retinopathy of prematurity.

Retinopathy of Prematurity (ROP) is a preventable neovascular retinal disease with a lifetime impact on vision and ocular morbidities. Retinal vessel immaturity and oxygen therapy, influenced or modulated by several risk factors including oxidative stress, intermittent hypoxia and desaturations, inflammation, infection, malnutrition, retinal growth factor deficiencies or excesses, and others are determinant factors of pathologic retinal angiogenesis and ROP. These factors are pharmacologic targets for prevention and/or rescue therapy. These drugs, include intravitreal anti-vascular endothelial growth factor drugs, erythropoietin, ocular propranolol, caffeine, antioxidants, insulin-like growth factor-I, and omega 3 poly-unsaturated fatty acids, and are promising therapies to prevent ROP, but require further studies. Topical ocular non-steroidal anti-inflammatory drugs (NSAIDs) target inflammatory cascade but the best, safest, and most effective ocular NSAID and formulation remain to be developed. Timing of drug intervention appears critical. Moreover, the complex interactions of the various pathophysiologic mechanisms resulting in aberrant angiogenesis thence ROP strongly suggest that drug combinations and synergisms may be required for effective prevention of ROP and a lifetime of blindness.

Comparing musicians and non-musicians in signal-in-noise perception.

Objectives: The objective is to compare musicians and non-musicians in signal-in-noise perception.Design: Participants underwent the following tests: (1) High-frequency (HF) audiometry, (2) QuickSIN (a test for speech perception in noise), and (3) Binaural Masking Level Difference (BMLD) test (a test that examines the hearing threshold of a low-frequency tone from noise masking when the phase of the signal or noise in one ear is reversed with respect to the phase of the signal or noise in the other ear, i.e. the difference in the threshold for detection of the tone in noise under the SπNo and SoNo conditions).Study sample: Thirty-four healthy young normal-hearing listeners including 17 musicians (M) and 17 non-musicians (NM).Results: There were no study group difference in HF audiometry and QuickSIN. The M group had a significantly better performance under the SoNo but not under the SπNo condition. As a result, the BMLD value (SoNo-SπNo) was significantly smaller in the M group than in the NM group.Conclusions: There is a musicians' advantage in binaural tone-in-noise detection in the BMLD task under the SoNo condition, suggesting that long-term music training positively shapes the auditory system.

Impact of Low-Level Blast Exposure on Brain Function after a One-Day Tactile Training and the Ameliorating Effect of a Jugular Vein Compression Neck Collar Device.

Special Weapons and Tactics (SWAT) personnel who conduct breacher exercises are at risk for blast-related head trauma. We aimed to investigate the potential impact of low-level blast exposure during breacher training on the neural functioning of working memory and auditory network connectivity. We also aimed to evaluate the effects of a jugular vein compression collar, designed to internally mitigate slosh energy absorption, preserving neural functioning and connectivity, following blast exposure. A total of 23 SWAT personnel were recruited and randomly assigned to a non-collar (n = 11) and collar group (n = 12). All participants completed a 1-day breacher training with multiple blast exposure. Prior to and following training, 18 participants (non-collar, n = 8; collar, n = 10) completed functional magnetic resonance imaging (fMRI) of working memory using N-Back task; 20 participants (non-collar, n = 10; collar, n = 12) completed resting-state fMRI. Key findings from the working memory analysis include significantly increased fMRI brain activation in the right insular, right superior temporal pole, right inferior frontal gyrus, and pars orbitalis post-training for the non-collar group (p < 0.05, threshold-free cluster enhancement corrected), but no changes were noted for the collar group. The elevation in fMRI activation in the non-collar group was found to correlate significantly (n = 7, r = 0.943, p = 0.001) with average peak impulse amplitude experienced during the training. In the resting-state fMRI analysis, significant pre- to post-training increase in connectivity between the auditory network and two discrete regions (left middle frontal gyrus and left superior lateral occipital/angular gyri) was found in the non-collar group, while no change was observed in the collar group. These data provided initial evidence of the impact of low-level blast on working memory and auditory network connectivity as well as the protective effect of collar on brain function following blast exposure, and is congruent with previous collar findings in sport-related traumatic brain injury.

Comparative Effects of Coenzyme Q10 or n-3 Polyunsaturated Fatty Acid Supplementation on Retinal Angiogenesis in a Rat Model of Oxygen-Induced Retinopathy.

Neonatal intermittent hypoxia (IH) or apnea afflicts 70% to 90% of all preterm infants <28 weeks gestation, and is associated with severe retinopathy of prematurity (ROP). We tested the hypotheses that coenzyme Q10 (CoQ10) or omega-3 polyunsaturated fatty acids (n-3 PUFAs) supplementation during neonatal IH reduces the severity of oxygen-induced retinopathy (OIR). Newborn rats were exposed to two IH paradigms: (1) 50% O2 with brief hypoxia (12% O2); or (2) 21% O2 with brief hypoxia, until postnatal day 14 (P14), during which they received daily oral CoQ10 in olive oil, n-3 PUFAs in fish oil, or olive oil only and compared to room air (RA) treated groups. Pups were examined at P14, or placed in RA until P21. Retinal angiogenesis, histopathology, and morphometry were determined. Both IH paradigms produced severe OIR, but these were worsened with 50/12% O2 IH. CoQ10 and n-3 PUFAs reduced the severity of OIR, as well as ocular growth factors in both IH paradigms, but CoQ10 was more effective in 50/12% O2 IH. Supplementation with either CoQ10 or n-3 PUFAs targeting IH-induced retinal injury is individually effective for ameliorating specific characteristics consistent with ROP. Given the complexity of ROP, further studies are needed to determine whether combined CoQ10 and n-3 PUFAs supplementation would optimize their efficacy and result in a better outcome.

Oxygen-Induced Retinopathy from Recurrent Intermittent Hypoxia Is Not Dependent on Resolution with Room Air or Oxygen, in Neonatal Rats.

Preterm infants often experience intermittent hypoxia (IH) with resolution in room air (RA) or hyperoxia (Hx) between events. Hypoxia is a major inducer of vascular endothelial growth factor, which plays a key role in normal and aberrant retinal angiogenesis. This study tested the hypothesis that neonatal IH which resolved with RA is less injurious to the immature retina than IH resolved by Hx between events. Newborn rats were exposed to: (1) Hx (50% O2) with brief hypoxia (12% O2); (2) RA with 12% O2; (3) Hx with RA; (4) Hx only; or (5) RA only, from P0 to P14. Pups were examined at P14 or placed in RA until P21. Retinal vascular and astrocyte integrity; retinal layer thickness; ocular and systemic biomarkers of angiogenesis; and somatic growth were determined at P14 and P21. All IH paradigms resulted in significant retinal vascular defects, disturbances in retinal astrocyte template, retinal thickening, and photoreceptor damage concurrent with elevations in angiogenesis biomarkers. These data suggest that the susceptibility of the immature retina to changes in oxygen render no differences in the outcomes between RA or O2 resolution. Interventions and initiatives to curtail O2 variations should remain a high priority to prevent severe retinopathy.

Impact of Chronic Neonatal Intermittent Hypoxia on Severity of Retinal Damage in a Rat Model of Oxygen-Induced Retinopathy.

Neonatal intermittent hypoxia (IH) followed by re-oxygenation in normoxia or supplemental oxygen (IHR) increases the risk for severe retinopathy of prematurity (ROP). The exact timing for the onset of retinal damage which may guide strategic interventions during retinal development, is unknown. We tested the hypothesis that chronic exposure of the immature retina to neonatal IH induces early manifestations of retinal damage that can be utilized as key time points for strategic pharmacologic intervention. Newborn rats were exposed to IH within 2 hours of birth (P0) until P14, or allowed to recover in room air (RA) from P14 to P21 (IHR). Retinal integrity and angiogenesis biomarkers were progressively assessed before (P0), during IH, and post IH (recovery in RA), or IHR, and compared to normoxic age-matched controls. Retinal damage occurred as early as day 3 of neonatal IH, consistent with vascular abnormalities and disturbances in the astrocytic template. These abnormalities worsened during IHR. Pharmacologic and non-pharmacologic interventions to identify, prevent, or minimize neonatal IH should be implemented shortly after birth in high risk preterm newborns. This strategy may lead to a reduction in the outcome of severe ROP requiring later invasive treatments.

Intermittent hypoxia suppression of growth hormone and insulin-like growth factor-I in the neonatal rat liver.

OBJECTIVES: Extremely low gestational age neonates with chronic lung disease requiring oxygen therapy frequently experience fluctuations in arterial oxygen saturation or intermittent hypoxia (IH). These infants are at risk for multi-organ developmental delay, reduced growth, and short stature. The growth hormone (GH)/insulin-like growth factor-I (IGF-1) system, an important hormonal regulator of lipid and carbohydrate metabolism, promotes neonatal growth and development. We tested the hypothesis that increasing episodes of IH delay neonatal growth by influencing the GH/IGF-I axis. DESIGN: Newborn rats were exposed to 2, 4, 6, 8, 10, or 12 hypoxic episodes (12% O2) during hyperoxia (50% O2) from P0-P7, P0-P14 (IH), or allowed to recover from P7-P21 or P14-P21 (IHR) in room air (RA). RA littermates at P7, P14, and P21 served as RA controls; and groups exposed to hyperoxia only (50% O2) served as zero IH controls. Histopathology of the liver; hepatic levels of GH, GHBP, IGF-I, IGFBP-3, and leptin; and immunoreactivities of GH, GHR, IGF-I and IGF-IR were determined. RESULTS: Pathological findings of the liver, including cellular swelling, steatosis, necrosis and focal sinusoid congestion were seen in IH, and were particularly severe in the P7 animals. Hepatic GH levels were significantly suppressed in the IH groups exposed to 6-12 hypoxic episodes per day and were not normalized during IHR. Deficits in the GH levels were associated with reduced body length and increase body weight during IHR suggesting increased adiposity and catchup fat. Catchup fat was also associated with elevations in GHBP, IGF-I, leptin. CONCLUSIONS: IH significantly impairs hepatic GH/IGF-1 signaling during the first few weeks of life, which is likely responsible for hepatic GH resistance, increased body fat, and hepatic steatosis. These hormonal perturbations may contribute to long-term organ and body growth impairment, and metabolic dysfunction in preterm infants experiencing frequent IH and/or apneic episodes.

Human retinal endothelial cells and astrocytes cultured on 3-D scaffolds for ocular drug discovery and development.

Topical ocular ketorolac improves the outcomes of severe retinopathy of prematurity and when administered with systemic caffeine, decreases the severity of oxygen-induced retinopathy. We tested the hypothesis that co-cultures of human retinal endothelial cells (HRECs) and human retinal astrocytes (HRAs) on 3-dimensional (3-D) hydrogel scaffolds is a more representative biomimetic paradigm of the blood-retinal-barrier (BRB) than 2-D cultures, and should be utilized for preclinical drug discovery and development. Mono- and co-cultures of HRECs and HRAs were treated with standard doses of ketorolac, ibuprofen, and/or caffeine, and exposed to hyperoxia, intermittent hypoxia (IH), or normoxia on 2-D surfaces or 3-D biodegradable hydrogel scaffolds (AlgiMatrix or Geltrex). Media and cells were collected at 72h post treatment for arachidonic acid metabolites. Cells cultured on 3-D scaffolds exhibited less oxidative stress and variability in drug responses. HRAs enhanced the responses of HRECs to drugs and changes in oxygen environment. PGE2 and PGI2 were the predominant prostanoids produced in response to IH, reflecting COX-2 immunoreactivity. We conclude that HRECs and HRAs co-cultured on 3-D scaffolds may recapitulate drug responses of the dynamic BRB and therefore should be implemented for preclinical ocular drug discovery and development.

Intermittent hypoxia alters dose dependent caffeine effects on renal prostanoids and receptors in neonatal rats.

Caffeine, one of the most commonly prescribed drugs in preterm neonates, is given in standard or suprapharmacologic doses. Although known as a diuretic, its effects in the neonatal kidneys are not well studied. We tested the hypothesis that neonatal intermittent hypoxia (IH) and high caffeine doses (HCD) alter renal regulators of vasomotor tone and water balance. Newborn rats were randomized to room air, hyperoxia, or IH and treated with standard or high caffeine doses; or placebo saline. Renal prostanoids; histopathology; and cyclooxygenase (COX), prostanoid receptor, and aquaporin (AQP) immunoreactivity were determined. HCD in IH caused severe pathological changes in the glomeruli and proximal tubules, consistent with acute kidney injury. This was associated with reductions in anthropometric growth, PGI2, and IP, DP, and AQP-4 immunoreactivity, well as a robust increase in COX-2, suggesting that the use of HCD should be avoided in preterm infants who experience frequent IH episodes.

Co-Enzyme Q10 and n-3 Polyunsaturated Fatty Acid Supplementation Reverse Intermittent Hypoxia-Induced Growth Restriction and Improved Antioxidant Profiles in Neonatal Rats.

Neonatal intermittent hypoxia (IH) increases the risk for many morbidities in extremely low birth weight/gestational age (ELBW/ELGA) neonates with compromised antioxidant systems and poor growth. We hypothesized that supplementation with coenzyme Q10 (CoQ10, ubiquinol) or n-3 polyunsaturated fatty acids (PUFAs) during neonatal IH improves antioxidant profiles and somatic growth in neonatal rats. Newborn rats were exposed to two IH paradigms at birth (P0): (1) 50% O2 with brief hypoxic episodes (12% O2); or (2) room air (RA) with brief hypoxia, until P14 during which they received daily oral CoQ10 in olive oil, n-3 PUFAs in fish oil, or olive oil only from P0 to P14. Pups were studied at P14 or placed in RA until P21 for recovery from IH (IHR). Body weight and length; organ weights; and serum antioxidants and growth factors were determined at P14 and P21. Neonatal IH resulted in sustained reductions in somatic growth, an effect that was reversed with n-3 PUFAs. Improved growth was associated with higher serum growth factors. CoQ10 decreased superoxide dismutase (SOD) and glutathione, but increased catalase, suggesting reduced oxidative stress. Further studies are needed to determine the synergistic effects of CoQ10 and n-3 PUFA co-administration for the prevention of IH-induced oxidative stress and postnatal growth deficits.

Non-steroidal Anti-inflammatory Drugs in Newborns and Infants.

Nonsteroidal antiinflammatory drugs (NSAIDs) and acetaminophen are used in young infants and newborns for pain and fever control, patent ductus closure, prevention of intraventricular hemorrhage, and potentially for prevention of retinopathy of prematurity. These drugs inhibit cyclooxygenase 1 (COX-1), COX-2, and peroxidases, thus, blocking prostaglandin (PG) synthesis. PGs are eicosanoids that regulate several physiologic, pathologic, and cellular processes, including vasomotor tone, platelet aggregation, sensitization of neurons to pain, and many molecular events critical to physiologic homeostasis. NSAIDs inhibit caspases and cell death. Increasing knowledge of these molecular entities may allow targeted drug development to prevent or minimize neonatal morbidities.

Intravitreal bevacizumab alters type IV collagenases and exacerbates arrested alveologenesis in the neonatal rat lungs.

Purpose/Aim: Intravitreal bevacizumab (Avastin) is an irreversible vascular endothelial growth factor (VEGF) inhibitor used off-label to treat severe retinopathy of prematurity in extremely low gestational age neonates. VEGF and matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) participate in lung maturation. We tested the hypothesis that intravitreal bevacizumab enters the systemic circulation and has long-lasting effects on lung MMPs. MATERIALS AND METHODS: Neonatal rats were exposed to: (1) hyperoxia (50% O2); (2) intermittent hypoxia (IH) (50% O2 with brief episodes of 12% O2); or (3) room air (RA) from birth (P0) to P14. At P14, the time of eye opening in rats, a single dose of Avastin (0.125 mg) was injected into the vitreous cavity of the left eye. A control group received equivalent volume saline. At P23 and P45, lung MMP-2 and MMP-9, and TIMP-1, and TIMP-2 were assessed in the lungs. RESULTS: At P23, Avastin increased MMP-2, MMP-9, and TIMP-1 levels in the hyperoxia group but decreased TIMP-1 levels in the IH group. The ratios of MMP-2/TIMP-1 and MMP-9/TIMP-1 were significantly elevated at P23 in the IH group treated with Avastin. At P45, the levels of MMP-2 and MMP-9 remained elevated in the hyperoxia and IH groups treated with Avastin, while a rebound increase in TIMP-1 levels was noted in the IH group. CONCLUSIONS: Avastin treatment in IH has lasting alterations in the balance between MMPs and their tissue inhibitors. These changes may lead to impaired alveologenesis and tissue damage consistent with bronchopulmonary dysplasia/chronic lung disease.

MnTBAP or Catalase Is More Protective against Oxidative Stress in Human Retinal Endothelial Cells Exposed to Intermittent Hypoxia than Their Co-Administration (EUK-134).

Retinopathy of prematurity is a blinding disease that affects extremely low gestational age neonates. Its etiology is due to extrauterinehyperoxia in an immature antioxidant system culminating as oxidative stress on the retina. Our aim is to elucidate the role of pharmacological antioxidants in modulating the biochemical and molecular response of human retinal microvascular endothelial cells (HRECs) exposed to oxidative stress. HRECs were treated with MnTBAP [a superoxide dismutase (SOD) mimetic], catalase, EUK-134 (SOD + catalase), or saline prior to exposure to normoxia (Nx), hyperoxia (Hx), or intermittent hypoxia (IH). Media levels of SOD, catalase, glutathione peroxidase (GPx), 8-isoPGF2α, and H2O2; cellular SOD and catalase; cellular function (migration and tube formation); and antioxidant gene expression were assessed. Pharmacological antioxidants had delayed suppressive effect on 8-isoPGF2α. MnTBAP and catalase were more effective for H2O2 scavenging in the media than co-administration in the form of EUK-134. A delayed response was noted in SOD and catalase media activity in MnTBAP- and catalase-treated cells, respectively in 50% and IH. MnTBAP had progressively increased media GPx in all oxygen conditions. Antioxidants resulted in normal, but more abundant tubulogenesis in IH and Hx. The distinct temporal response to oxidative stress reflected the respective antioxidant's potency and catalytic properties. The cell permeability of the antioxidants limited the ability to scavenge intracellular free radicals. The results support that MnTBAP or catalase may be more effective for the prevention of oxidative stress in oxygen-induced retinopathy.

Chronic Intermittent Hypoxia Causes Lipid Peroxidation and Altered Phase 1 Drug Metabolizing Enzymes in the Neonatal Rat Liver.

Critically ill preterm neonates requiring oxygen therapy often experience frequent apneas with intermittent hypoxia (IH). IH-induced oxidative stress causes lipid peroxidation, which targets the liver and contributes to toxic drug reactions. We tested the hypothesis that incremental IH episodes induce oxidative damage in the neonatal liver and alter the expression of genes that regulate drug metabolism. Newborn rats were exposed to increasing IH episodes (12% O2) during hyperoxia (50% O2), or placed in room air (RA) until postnatal day 21 (P21) for recovery from IH (IHR). RA littermates served as controls, and pups exposed to 50% O2 served as hyperoxia controls. Hepatic histopathology, biomarkers of oxidative stress and oxidative DNA damage, antioxidants, and expression of genes that regulate drug metabolism were assessed. Oxidative stress and DNA damage, evidenced by 8-isoprostaglandin F2α (8-isoPGF2α) and 8-hydroxy-2'-deoxyguanosine (8-OH-dG), respectively, increased as a function of IH episodes, and was associated with decreased superoxide dismutase (SOD) and increased catalase activities. Pathological changes including cellular swelling, steatosis, necrosis, and focal sinusoid congestion were seen in IH, but not in IHR. Similarly, IH was associated with upregulation of several genes involved in DNA repair, which were downregulated during IHR. Of the genes involved in drug metabolism, aldehyde dehydrogenases (involved in lipid peroxidation) and cytochrome P450 (CYP) genes of the 2C family (involved in oxidative stress) were robustly upregulated both in IH and in IHR. Hepatic oxidative stress and lipid peroxidation occurring in response to chronic IH have implications for preterm infants, and may explain, in part, the pharmacokinetic variations and drug toxicities in this vulnerable population.