Differential contribution of mitochondria, NADPH oxidases, and glycolysis to region-specific oxidant stress in the anoxic-reoxygenated embryonic heart.

The ability of the developing myocardium to tolerate oxidative stress during early gestation is an important issue with regard to possible detrimental consequences for the fetus. In the embryonic heart, antioxidant defences are low, whereas glycolytic flux is high. The pro- and antioxidant mechanisms and their dependency on glucose metabolism remain to be explored. Isolated hearts of 4-day-old chick embryos were exposed to normoxia (30 min), anoxia (30 min), and hyperoxic reoxygenation (60 min). The time course of ROS production in the whole heart and in the atria, ventricle, and outflow tract was established using lucigenin-enhanced chemiluminescence. Cardiac rhythm, conduction, and arrhythmias were determined. The activity of superoxide dismutase, catalase, gutathione reductase, and glutathione peroxidase as well as the content of reduced and oxidized glutathione were measured. The relative contribution of the ROS-generating systems was assessed by inhibition of mitochondrial complexes I and III (rotenone and myxothiazol), NADPH oxidases (diphenylene iodonium and apocynine), and nitric oxide synthases (N-monomethyl-l-arginine and N-iminoethyl-l-ornithine). The effects of glycolysis inhibition (iodoacetate), glucose deprivation, glycogen depletion, and lactate accumulation were also investigated. In untreated hearts, ROS production peaked at 10.8 ± 3.3, 9 ± 0.8, and 4.8 ± 0.4 min (means ± SD; n = 4) of reoxygenation in the atria, ventricle, and outflow tract, respectively, and was associated with arrhythmias. Functional recovery was complete after 30-40 min. At reoxygenation, 1) the respiratory chain and NADPH oxidases were the main sources of ROS in the atria and outflow tract, respectively; 2) glucose deprivation decreased, whereas glycogen depletion increased, oxidative stress; 3) lactate worsened oxidant stress via NADPH oxidase activation; 4) glycolysis blockade enhanced ROS production; 5) no nitrosative stress was detectable; and 6) the glutathione redox cycle appeared to be a major antioxidant system. Thus, the glycolytic pathway plays a predominant role in reoxygenation-induced oxidative stress during early cardiogenesis. The relative contribution of mitochondria and extramitochondrial systems to ROS generation varies from one region to another and throughout reoxygenation.

Impaired uptake of glutathione by hepatic mitochondria from chronic ethanol-fed rats. Tracer kinetic studies in vitro and in vivo and susceptibility to oxidant stress.

Isolated hepatocytes incubated with [35S]-methionine were examined for the time-dependent accumulation of [35S]-glutathione (GSH) in cytosol and mitochondria, the latter confirmed by density gradient purification. In GSH-depleted and -repleted hepatocytes, the increase of specific activity of mitochondrial GSH lagged behind cytosol, reaching nearly the same specific activity by 1-2 h. However, in hepatocytes from ethanol-fed rats, the rate of increase of total GSH specific radioactivity in mitochondria was markedly suppressed. In in vivo steady-state experiments, the mass transport of GSH from cytosol to mitochondria and vice versa was 18 nmol/min per g liver, indicating that the half-life of mitochondrial GSH was approximately 18 min in controls. The fractional transport rate of GSH from cytosol to mitochondria, but not mitochondria to cytosol, was significantly reduced in the livers of ethanol-fed rats. Thus, ethanol-fed rats exhibit a decreased mitochondrial GSH pool size due to an impaired entry of cytosol GSH into mitochondria. Hepatocytes from ethanol-fed rats exhibited a greater susceptibility to the oxidant stress-induced cell death from tert-butylhydroperoxide. Incubation with glutathione monoethyl ester normalized the mitochondrial GSH and protected against the increased susceptibility to t-butylhydroperoxide, which was directly related to the lowered mitochondrial GSH pool size in ethanol-fed cells.

The JAK2/STAT3 pathway in the embryonic chick heart submitted to anoxia, reoxygenation and oxidant stress

SUMMARYAim: The embryonic/fetal heart is highly sensitive to oxygenation level and a transient uteroplacental hypoperfusion can lead to oxyradicals overproduction. Information about the molecular mechanisms underlying ischemia-reperfusion (I-R) injury in the developing heart is lacking. The Janus Kinase 2 / Signal Transducer and Activator of Transcription 3 (JAK2/STAT3) pathway, required for cardiogenesis and involved in protection of the adult heart against I-R, could also play a key role in the response of the fetal myocardium to transient oxygen deprivation. The aim of the study was to characterize the involvement of JAK2/STAT3 pathway and its interaction with other signalling pathways in the developing heart transiently submitted to anoxia. Furthermore, the response of the embryonic heart to an exogenous oxidant stress (H2O2) in comparison to reoxygenation-induced endogenous oxyradicals has been investigated.Methods: Hearts isolated from 4-day-old chick embryos were submitted to anoxia (30min) and reoxygenation (80min) with or without the antioxidant MPG, the JAK2/STAT3 inhibitor AG490 or exposed to H202 (50|iM-lmM). The time course of phosphorylation of STAT3atyr0Sine7 and Reperfusion Injury Salvage Kinase (RISK) proteins (PI3K, Akt, GSK3B, Glycogen Synthase and ERK2) was determined in homogenate" and in enriched nuclear and cytoplasmic fractions. The STAT3 DNA-binding was determined by EMSA and the expression of STAT3 specific target genes by RT-PCR. The chrono-, dromo- and inotropic disturbances were also investigated by ECG and mechanical recordings.Results: Phosphorylation of STATSaP (P-Tyr STAT3a) was increased by reoxygenation and reduced by MPG or AG490. STAT3 and GSK36 were detected both in nuclear and cytoplasmic fractions while PI3K, Akt, GS and ERK2 were restricted to cytoplasm. Reoxygenation led to nuclear accumulation of STAT3 but unexpectedly without DNA- binding. AG490 decreased the reoxygenation-induced phosphorylation of STABa^, Akt, GS and ERK2 and phosphorylation/inhibition of GSK3B in the nucleus, exclusively. Inhibition of JAK2/STAT3 delayed recovery of atrial rate, worsened RR. variability and prolonged arrhythmias compared to control hearts. Cardiac activity was altered only at concentrations >500μΜ of H2O2. Moreover, ImM of H2O2 suppressed atrial activity in 45% of the hearts, atrioventricular conduction in 66% and augmented P-Tyr STAT3awhich led to an increase in the DNA-binding but no change in the expression of three STAT3 specific target genes (iNOS, MnSOD, Cox-2).Conclusion: In the developing heart, besides its nuclear translocation without transcriptional activity, ROS-activated STAT3a can rapidly interact with RISK proteins present in nucleus and cytoplasm and reduce the anoxia-reoxygenation-induced arrhythmias. Moreover, the embryonic heart is highly resistant to H2O2 and the atrial region is the less affected. The role of JAK2/STAT3 in the response to reoxygenation-induced oxyradicals is different from the response to strong exogenous oxidant stress where STAT3 DNA-binding activity is increased. Such findings provide a first step in understanding the modulation of signalling cascades in the fetal heart submitted to transient intrauterine oxygen deprivation.RESUMEIntroduction: Le coeur embryonnaire et foetal est très sensible au manque d'oxygène et une hypoperfusion utéroplacentaire transitoire peut conduire à une surproduction d'espèces radicalaires (ROS). Dans le coeur en développement les mécanismes moléculaires impliqués en situation d'ischémie-reperfusion (I-R) ne sont pas connus. La voie de signalisation JAK2/STAT3 (Janus Kinase 2 / Signal Transducer and Activator of Transcription 3), impliquée aussi bien dans la cardiogenèse précoce que dans la protection du coeur adulte contre l'I-R, pourrait jouer un rôle clé dans la réponse du myocarde foetal à un déficit en oxygène. Cette étude a permis d'étudier le rôle de la voie JAK2/STAT3 et son interaction avec d'autres voies de signalisation dans un modèle de coeur embryonnaire soumis à un épisode anoxique. En outre, les effets du stress oxydant endogène provoqué par la réoxygénation ont été comparés à ceux du stress oxydatif exogène induit par du peroxyde d'hydrogène (H2O2).Méthodes: Des coeurs isolés d'embryons de poulet âgés de 4 jours ont été soumis à une anoxie (30min) suivie d'une réoxygénation (80min) en présence ou non de l'antioxydant MPG et de l'inhibiteur de JAK2/STAT3 AG490 ou exposés à de 1Ή202 (50μΜ-1πιΜ). L'évolution temporelle de la phosphorylation de 8ΤΑΤ3α*ΓΟδίη6705 (P-Tyr STAT3a) et celle de la phosphorylation des protéines de la voie RISK (Reperfusion Injury Salvage Kinase: PI3K, Akt, GSK3B, glycogène synthase GS et ERK2) ont été déterminés dans l'homogénat et dans les fractions nucléaire et cytopiasmique du myocarde. La liaison de STAT3 à l'ADN a été déterminée par EMSA et l'expression de gènes cibles de STAT3 (iNOS, MnSOD, Cox2) par RT-PCR. Les effets chrono-, dromo- et inotropes ont été déterminés par les enregistrements de l'ECG et de l'activité contractile ventriculaire.Résultats: STAT3 et GSK3B étaient présents dans les fractions nucléaire et cytopiasmique tandis que PI3K, Akt, GS et ERK2 n'étaient détectées que dans la fraction cytopiasmique. L'augmentation de P-Tyr STAT3a provoquée par la réoxygénation était significativement réduite par le MPG ou PAG490. La réoxygénation entraînait l'accumulation nucléaire de STAT3, mais étonnamment sans liaison avec l'ADN. A la réoxygénation TAG490 diminuait la phosphorylation d'Akt, GS et ERK2 ainsi que celle de GSK36 mais exclusivement dans la fraction nucléaire. L'inhibition de JAK2/STAT3 retardait également la récupération du rythme cardiaque et prolongeait la durée des arythmies. L'activité cardiaque n'était perturbée par de ΓΗ2Ο2 qu'à des concentrations >500μΜ. A ImM, ΓΗ2Ο2 supprimait l'activité auriculaire dans 45% des coeurs et la conduction auriculo-ventriculaire dans 66% et augmentait la formation de P-Tyr STAT3a et sa liaison à l'ADN sans modifier l'expression des gènes cibles.Conclusion: Les ROS produits par l'anoxie-réoxygénation activent STAT3a qui subit une translocation dans le noyau sans se lier à l'ADN et interagit rapidement avec des protéines de la voie RISK dans les compartiments nucléaire et cytopiasmique du coeur embryonnaire. Ce dernier, en particulier au niveau des oreillettes, se révèle très résistant au puissant stress oxydatif de l'H202 qui se différencie du stress lié à la réoxygénation en favorisant la liaison de STAT3 à l'ADN. Ces résultats originaux permettent une meilleure compréhension des mécanismes qui peuvent améliorer la récupération du coeur en développement après un épisode hypoxique intra-utérin.

Compounds that bind to the gamma-aminobutyric acid benzodiazepine ionophore complex modulate the cellular response to oxidant stress

The γ-aminobutyric acid benzodiazepine (GABAA /BZDR) ionophore complex has been widely studied in the central nervous system (CNS) and it regulates Cl− ion movement across the plasma membrane. The complex has been found in the distal tubule and the thick ascending limb of the kidney. The goal of this study was to see if modulation of this complex by agonists or antagonists could affect the way Madin-Darby Canine Kidney (MDCK) cells responded to an oxidant stress induced by menadione. When compared to cells incubated with menadione alone, preincubation with lindane, a nonspecific GABAA antagonist, coincubation with bicuculline, a specific GABAA antagonist, and coincubation with FG7142, an inverse agonist for the BZDR, protected cells from menadione cytotoxicity. Preincubation of cells in media containing PK11195 had no effect on menadione cytotoxicity. Coincubation with flurazepam, a BZDR agonist, exacerbated menadione cytotoxicity. This suggests that modulation of the GABAA/BZDR ionophore complex within MDCK cells with agonists and antagonists can alter the cellular responsiveness to an oxidant-induced injury. These responses via agonists and antagonists may be due to alterations of Cl− ion influx during late stage necrotic cell death. ^

Cellular prion protein (PrP(C)) and superoxide dismutase (SOD) in vascular cells under oxidative stress

The PrP(C) is expressed in several cell types but its physiological function is unknown. Some studies associate the PrP(C) with copper metabolism and the antioxidant activity of SOD. Our hypothesis was that changes in PrP(C) expression lead to abnormal copper regulation and induce SOD downregulation in the vascular wall. Objectives: to study whether the PrP(C) expression undergoes induction by agents that trigger endoplasmic reticulum stress (ERS) and, in this context, to evaluate the SOD activity. Methods: To trigger ERS, in vitro, rabbit aortic smooth muscle cells were challenged for 4, 8 and 18 hours, with angiotensin-II, tunicamycin and 7-ketocholesterol. For in vivo studies rabbit aortic arteries were subjected to injury by balloon catheter. Results: In vitro baseline SOD activity, determined through inhibition of cytochrome-c reduction, was 13.9 +/- 1.2 U/mg protein, angiotensin-II exposed for 8 hours produced an increase in SOD activity, and cellular copper concentration was about 9 times greater only under these conditions. Western blotting analysis for SOD isoenzymes showed an expression profile that was not correlated with the enzymatic activity. PrP(C) expression decreased after exposure to all agents after different incubation periods. RT-PCR assay showed increased mRNA expression for PrP(C) only in cells stimulated for 8 hours with the different stressors. The PrP(C) mRNA expression in rabbit aortic artery fragments, subjected to balloon catheter injury, showed a pronounced increase immediately after overdistension. The results obtained indicated a PrP(C) protection factor during the early part of the ERS exposure period, but did not demonstrate a SOD-like profile for the PrP(C). (C) 2009 Elsevier GmbH. All rights reserved.

CD40 ligation protects bronchial epithelium against oxidant-induced caspase-independent cell death

CD40 and its ligand regulate pleiotropic biological responses, including cell proliferation, differentiation, and apoptosis. In many inflammatory lung diseases, tissue damage by environmental or endogenous oxidants plays a major role in disease pathogenesis. As the epithelial barrier is a major target for these oxidants, we postulated that CD40, the expression of which is increased in asthma, plays a role in the regulation of apoptosis of bronchial epithelial cells exposed to oxidants. Using 16HBE 14o- cells exposed to oxidant stress, we found that ligation of CD40 (induced by G28-5 monoclonal antibodies) enhanced cell survival and increased the number of cells in G2/M (interphase between DNA synthesis and mitosis) of the cell cycle. This was associated with NF-kappaB and activator protein-1 activation and increased expression of the inhibitor of apoptosis, c-IAP1. However, oxidant stress-induced apoptosis was found to be caspase- and calpain-independent implicating CD40 ligation as a regulator of caspase-independent cell death. This was confirmed by the demonstration that CD40 ligation prevented mitochondrial release and nuclear translocation of apoptosis inducing factor. In conclusion, we demonstrate a novel role for CD40 as a regulator of epithelial cell survival against oxidant stress. Furthermore, we have identified, for the first time, an endogenous inhibitory pathway of caspase-independent cell death.

An Apparent Paradox: Attenuation of Phenylephrine-mediated Calcium Mobilization and Hyperreactivity to Phenylephrine in Contralateral Carotid After Balloon Injury

Balloon catheter injury promotes hyperreactivity to phenylephrine (Phe) in the contralateral carotid. Phe-induced contraction involves calcium mobilization, a process that may be sensitive to reactive oxygen species. In this study, we investigated whether increased reactivity to Phe in the contralateral carotid is due to alterations in calcium mobilization by Phe and reactive oxygen species signaling. Concentration-response curves to Phe were obtained in control and contralateral arteries 4 days after balloon injury. Tiron did not modify E(max) to Phe in control arteries but reduced this parameter in the contralateral carotid to control levels. Moreover, immunofluorescence to dihydroethydine showed increased basal oxidative stress in the contralateral artery compared with control artery. Intracellular calcium mobilization by Phe in the contralateral artery was not different from control, but Phe-induced extracellular calcium mobilization was reduced in the contralateral artery compared with that in the control. These data were confirmed by confocal microscopy using Fluo 3-AM. Tiron and SC-236 increased Phe-induced calcium influx in the contralateral artery, which was similar to controls in the same conditions. However, catalase did not modify this response. Taken together, our results suggest that superoxide anions and prostanoids from cyclooxygenase-2 alter pathways downstream of alpha(1)-adrenoceptor activation in the contralateral carotid in response to injury. This results in reduced Phe-induced calcium influx, despite hyperreactivity to Phe.

Role of promoter polymorphisms in the plasma glutathione peroxidase (GPx-3) gene as a risk factor for cerebral venous thrombosis

Background and Purpose-Plasma glutathione peroxidase (GPx-3) is a major antioxidant enzyme in plasma and the extracellular space that scavenges reactive oxygen species produced during normal metabolism or after oxidative insult. A deficiency of this enzyme increases extracellular oxidant stress, promotes platelet activation, and may promote oxidative posttranslational modification of fibrinogen. We recently identified a haplotype (H-2) in the GPx-3 gene promoter that increases the risk of arterial ischemic stroke among children and young adults. Methods-The aim of this study is to identify possible relationships between promoter haplotypes in the GPx-3 gene and cerebral venous thrombosis (CVT). We studied the GPx-3 gene promoter from 23 patients with CVT and 123 young controls (18 to 45 years) by single-stranded conformational polymorphism and sequencing analysis. Results-Over half of CVT patients (52.1%) were heterozygous (H1H2) or homozygous (H2H2) carriers of the H-2 haplotype compared with 12.2% of controls, yielding a more than 10-fold independent increase in the risk of CVT (OR=10.7; 95% CI, 2.70 to 42.36; P<0.0001). Among women, the interaction of the H2 haplotype with hormonal risk factors increased the OR of CVT to almost 70 (P<0.0001). Conclusions-These findings show that a novel GPx-3 promoter haplotype is a strong, independent risk factor for CVT. As we have previously shown that this haplotype is associated with a reduction in transcriptional activity, which compromises antioxidant activity and antithrombotic benefits of the enzyme, these results suggest that a deficiency of GPx-3 leads to a cerebral venous thrombophilic state.

Oxidants positively or negatively regulate nuclear factor kappaB in a context-dependent manner.

Redox-based mechanisms play critical roles in the regulation of multiple cellular functions. NF-kappaB, a master regulator of inflammation, is an inducible transcription factor generally considered to be redox-sensitive, but the modes of interactions between oxidant stress and NF-kappaB are incompletely defined. Here, we show that oxidants can either amplify or suppress NF-kappaB activation in vitro by interfering both with positive and negative signals in the NF-kappaB pathway. NF-kappaB activation was evaluated in lung A549 epithelial cells stimulated with tumor necrosis factor alpha (TNFalpha), either alone or in combination with various oxidant species, including hydrogen peroxide or peroxynitrite. Exposure to oxidants after TNFalpha stimulation produced a robust and long lasting hyperactivation of NF-kappaB by preventing resynthesis of the NF-kappaB inhibitor IkappaB, thereby abrogating the major negative feedback loop of NF-kappaB. This effect was related to continuous activation of inhibitor of kappaB kinase (IKK), due to persistent IKK phosphorylation consecutive to oxidant-mediated inactivation of protein phosphatase 2A. In contrast, exposure to oxidants before TNFalpha stimulation impaired IKK phosphorylation and activation, leading to complete prevention of NF-kappaB activation. Comparable effects were obtained when interleukin-1beta was used instead of TNFalpha as the NF-kappaB activator. This study demonstrates that the influence of oxidants on NF-kappaB is entirely context-dependent, and that the final outcome (activation versus inhibition) depends on a balanced inhibition of protein phosphatase 2A and IKK by oxidant species. Our findings provide a new conceptual framework to understand the role of oxidant stress during inflammatory processes.

The emerging role of Nrf2 in dermatotoxicology.

The nuclear factor erythroid 2-related factor 2 (Nrf2) is best known for its role in resistance to oxidant stress. In this issue of EMBO Molecular Medicine, Nrf2-prolonged genetic activation is shown with devastating effects on skin homeostasis. The study provides novel molecular insights into poison-induced chloracne and metabolizing acquired dioxin-induced skin hamartomas or MADISH.

Comparative protein profiling identifies elongation factor-1beta and tryparedoxin peroxidase as factors associated with metastasis in Leishmania guyanensis.

Parasites of the Leishmania Viannia subgenus are major causative agents of mucocutaneous leishmaniasis (MCL), a disease characterised by parasite dissemination (metastasis) from the original cutaneous lesion to form debilitating secondary lesions in the nasopharyngeal mucosa. We employed a protein profiling approach to identify potential metastasis factors in laboratory clones of L. (V.) guyanensis with stable phenotypes ranging from highly metastatic (M+) through infrequently metastatic (M+/M-) to non-metastatic (M-). Comparison of the soluble proteomes of promastigotes by two-dimensional electrophoresis revealed two abundant protein spots specifically associated with M+ and M+/M- clones (Met2 and Met3) and two others exclusively expressed in M- parasites (Met1 and Met4). The association between clinical disease phenotype and differential expression of Met1-Met4 was less clear in L. Viannia strains from mucosal (M+) or cutaneous (M-) lesions of patients. Identification of Met1-Met4 by biological mass spectrometry (LC-ES-MS/MS) and bioinformatics revealed that M+ and M- clones express distinct acidic and neutral isoforms of both elongation factor-1 subunit beta (EF-1beta) and cytosolic tryparedoxin peroxidase (TXNPx). This interchange of isoforms may relate to the mechanisms by which the activities of EF-1beta and TXNPx are modulated, and/or differential post-translational modification of the gene product(s). The multiple metabolic functions of EF-1 and TXNPx support the plausibility of their participation in parasite survival and persistence and thereby, metastatic disease. Both polypeptides are active in resistance to chemical and oxidant stress, providing a basis for further elucidation of the importance of antioxidant defence in the pathogenesis underlying MCL.

Insulin-Like growth-factor 1 myocardial expression decreases in chronic alcohol consumption

Background Chronic alcohol ingestion may cause severe biochemical and pathophysiological derangements to skeletal muscle. Unfortunately, these alcohol-induced events may also prime skeletal muscle for worsened, delayed, or possibly incomplete repair following acute injury. As alcoholics may be at increased risk for skeletal muscle injury, our goals were to identify the effects of chronic alcohol ingestion on components of skeletal muscle regeneration. To accomplish this, age- and gender-matched C57Bl/6 mice were provided normal drinking water or water that contained 20% alcohol (v/v) for 1820 wk. Subgroups of mice were injected with a 1.2% barium chloride (BaCl2) solution into the tibialis anterior (TA) muscle to initiate degeneration and regeneration processes. Body weights and voluntary wheel running distances were recorded during the course of recovery. Muscles were harvested at 2, 7 or 14 days post-injection and assessed for markers of inflammation and oxidant stress, fiber cross-sectional areas, levels of growth and fibrotic factors, and fibrosis. Results Body weights of injured, alcohol-fed mice were reduced during the first week of recovery. These mice also ran significantly shorter distances over the two weeks following injury compared to uninjured, alcoholics. Injured TA muscles from alcohol-fed mice had increased TNFα and IL6 gene levels compared to controls 2 days after injury. Total protein oxidant stress and alterations to glutathione homeostasis were also evident at 7 and 14 days after injury. Ciliary neurotrophic factor (CNTF) induction was delayed in injured muscles from alcohol-fed mice which may explain, in part, why fiber cross-sectional area failed to normalize 14 days following injury. Gene levels of TGFβ1 were induced early following injury before normalizing in muscle from alcohol-fed mice compared to controls. However, TGFβ1 protein content was consistently elevated in injured muscle regardless of diet. Fibrosis was increased in injured, muscle from alcohol-fed mice at 7 and 14 days of recovery compared to injured controls. Conclusions Chronic alcohol ingestion appears to delay the normal regenerative response following significant skeletal muscle injury. This is evidenced by reduced cross-sectional areas of regenerated fibers, increased fibrosis, and altered temporal expression of well-described growth and fibrotic factors.

Physiopathology of the embryonic heart (with special emphasis on hypoxia and reoxygenation).

The adaptative response of the developing heart to adverse intrauterine environment such as reduced O2 delivery can result in alteration of gene expression with short- and long-term consequences including adult cardiovascular diseases. The tolerance of the developing heart of acute or chronic oxygen deprivation, its capacity to recover during reperfusion and the mechanisms involved in reoxygenation injury are still under debate. Indeed, the pattern of response of the immature myocardium to hypoxia-reoxygenation differs from that of the adult. This review deals with the structural and metabolic characteristics of the embryonic heart and the functional consequences of hypoxia and reoxygenation. The relative contribution of calcium and sodium overload, pH disturbances and oxidant stress to the hypoxia-induced cardiac dysfunction is examined, as well as various cellular signaling pathways (e.g. MAP kinases) involved in cell survival or death. In the context of the recent advances in developmental cardiology and fetal cardiac surgery, a better understanding of the physiopathology of the stressed developing heart is required.

Insulin-Like growth-factor 1 myocardial expression decreases in chronic alcohol consumption

Background Chronic alcohol ingestion may cause severe biochemical and pathophysiological derangements to skeletal muscle. Unfortunately, these alcohol-induced events may also prime skeletal muscle for worsened, delayed, or possibly incomplete repair following acute injury. As alcoholics may be at increased risk for skeletal muscle injury, our goals were to identify the effects of chronic alcohol ingestion on components of skeletal muscle regeneration. To accomplish this, age- and gender-matched C57Bl/6 mice were provided normal drinking water or water that contained 20% alcohol (v/v) for 18-20 wk. Subgroups of mice were injected with a 1.2% barium chloride (BaCl2) solution into the tibialis anterior (TA) muscle to initiate degeneration and regeneration processes. Body weights and voluntary wheel running distances were recorded during the course of recovery. Muscles were harvested at 2, 7 or 14 days post-injection and assessed for markers of inflammation and oxidant stress, fiber cross-sectional areas, levels of growth and fibrotic factors, and fibrosis. Results Body weights of injured, alcohol-fed mice were reduced during the first week of recovery. These mice also ran significantly shorter distances over the two weeks following injury compared to uninjured, alcoholics. Injured TA muscles from alcohol-fed mice had increased TNFα and IL6 gene levels compared to controls 2 days after injury. Total protein oxidant stress and alterations to glutathione homeostasis were also evident at 7 and 14 days after injury. Ciliary neurotrophic factor (CNTF) induction was delayed in injured muscles from alcohol-fed mice which may explain, in part, why fiber cross-sectional area failed to normalize 14 days following injury. Gene levels of TGFβ1 were induced early following injury before normalizing in muscle from alcohol-fed mice compared to controls. However, TGFβ1 protein content was consistently elevated in injured muscle regardless of diet. Fibrosis was increased in injured, muscle from alcohol-fed mice at 7 and 14 days of recovery compared to injured controls. Conclusions Chronic alcohol ingestion appears to delay the normal regenerative response following significant skeletal muscle injury. This is evidenced by reduced cross-sectional areas of regenerated fibers, increased fibrosis, and altered temporal expression of well-described growth and fibrotic factors.

Dietary Strategies to Optimize Wound Healing after Periodontal and Dental Implant Surgery: An Evidence-Based Review

Methods to optimize healing through dietary strategies present an attractive option for patients, such that healing from delicate oral surgeries occurs as optimally as possible with minimal patient-meditated complications through improper food choices. This review discusses findings from studies that have investigated the role of diet, either whole foods or individual dietary components, on periodontal health and their potential role in wound healing after periodontal surgery. To date, research in this area has largely focused on foods or individual dietary components that may attenuate inflammation or oxidant stress, or foster de novo bone formation. These studies suggest that a wide variety of dietary components, including macronutrients and micronutrients, are integral for optimal periodontal health and have the potential to accelerate oral wound healing after periodontal procedures. Moreover, this review provides guidance regarding dietary considerations that may help a patient achieve the best possible outcome after a periodontal procedure.