Blood and Brain Metabolites after Cerebral Ischemia

The study of an organism's response to cerebral ischemia at different levels is essential to understanding the mechanism of the injury and protection. A great interest is devoted to finding the links between quantitative metabolic changes and post-ischemic damage. This work aims to summarize the outcomes of the most studied metabolites in brain tissue-lactate, glutamine, GABA (4-aminobutyric acid), glutamate, and NAA (N-acetyl aspartate)-regarding their biological function in physiological conditions and their role after cerebral ischemia/reperfusion. We focused on ischemic damage and post-ischemic recovery in both experimental-including our results-as well as clinical studies. We discuss the role of blood glucose in view of the diverse impact of hyperglycemia, whether experimentally induced, caused by insulin resistance, or developed as a stress response to the cerebral ischemic event. Additionally, based on our and other studies, we analyze and critically discuss post-ischemic alterations in energy metabolites and the elevation of blood ketone bodies observed in the studies on rodents. To complete the schema, we discuss alterations in blood plasma circulating amino acids after cerebral ischemia. So far, no fundamental brain or blood metabolite(s) has been recognized as a relevant biological marker with the feasibility to determine the post-ischemic outcome or extent of ischemic damage. However, studies from our group on rats subjected to protective ischemic preconditioning showed that these animals did not develop post-ischemic hyperglycemia and manifested a decreased metabolic infringement and faster metabolomic recovery. The metabolomic approach is an additional tool for understanding damaging and/or restorative processes within the affected brain region reflected in the blood to uncover the response of the whole organism via interorgan metabolic communications to the stressful cerebral ischemic challenge.

Age-Dependent Changes in Calcium Regulation after Myocardial Ischemia-Reperfusion Injury

During aging, heart structure and function gradually deteriorate, which subsequently increases susceptibility to ischemia-reperfusion (IR). Maintenance of Ca²⁺ homeostasis is critical for cardiac contractility. We used Langendorff's model to monitor the susceptibility of aging (6-, 15-, and 24-month-old) hearts to IR, with a specific focus on Ca²⁺-handling proteins. IR, but not aging itself, triggered left ventricular changes when the maximum rate of pressure development decreased in 24-month-olds, and the maximum rate of relaxation was most affected in 6-month-old hearts. Aging caused a deprivation of Ca²⁺-ATPase (SERCA2a), Na⁺/Ca²⁺ exchanger, mitochondrial Ca²⁺ uniporter, and ryanodine receptor contents. IR-induced damage to ryanodine receptor stimulates Ca²⁺ leakage in 6-month-old hearts and elevated phospholamban (PLN)-to-SERCA2a ratio can slow down Ca²⁺ reuptake seen at 2-5 μM Ca²⁺. Total and monomeric PLN mirrored the response of overexpressed SERCA2a after IR in 24-month-old hearts, resulting in stable Ca²⁺-ATPase activity. Upregulated PLN accelerated inhibition of Ca²⁺-ATPase activity at low free Ca²⁺ in 15-month-old after IR, and reduced SERCA2a content subsequently impairs the Ca²⁺-sequestering capacity. In conclusion, our study suggests that aging is associated with a significant decrease in the abundance and function of Ca²⁺-handling proteins. However, the IR-induced damage was not increased during aging.

Metabolic Changes Induced by Cerebral Ischemia, the Effect of Ischemic Preconditioning, and Hyperhomocysteinemia

¹H Nuclear Magnetic Resonance (NMR) metabolomics is one of the fundamental tools in the fast-developing metabolomics field. It identifies and quantifies the most abundant metabolites, alterations of which can describe energy metabolism, activated immune response, protein synthesis and catabolism, neurotransmission, and many other factors. This paper summarizes our results of the ¹H NMR metabolomics approach to characterize the distribution of relevant metabolites and their alterations induced by cerebral ischemic injury or its combination with hyperhomocysteinemia in the affected tissue and blood plasma in rodents. A decrease in the neurotransmitter pool in the brain tissue likely follows the disordered feasibility of post-ischemic neurotransmission. This decline is balanced by the increased tissue glutamine level with the detected impact on neuronal health. The ischemic injury was also manifested in the metabolomic alterations in blood plasma with the decreased levels of glycolytic intermediates, as well as a post-ischemically induced ketosis-like state with increased plasma ketone bodies. As the 3-hydroxybutyrate can act as a likely neuroprotectant, its post-ischemic increase can suggest its supporting role in balancing ischemic metabolic dysregulation. Furthermore, the ¹H NMR approach revealed post-ischemically increased 3-hydroxybutyrate in the remote organs, such as the liver and heart, as well as decreased myocardial glutamate. Ischemic preconditioning, as a proposed protective strategy, was manifested in a lower extent of metabolomic changes and/or their faster recovery in a longitudinal study. The paper also summarizes the pre- and post-ischemic metabolomic changes in the rat hyperhomocysteinemic models. Animals are challenged with hyperglycemia and ketosis-like state. A decrease in several amino acids in plasma follows the onset and progression of hippocampal neuropathology when combined with ischemic injury. The ¹H NMR metabolomics approach also offers a high potential for metabolites in discriminatory analysis in the search for potential biomarkers of ischemic injury. Based on our results and the literature data, this paper presents valuable findings applicable in clinical studies and suggests the precaution of a high protein diet, especially foods which are high in Met content and low in B vitamins, in the possible risk of human cerebrovascular neuropathology.

An Ecological Study Indicates the Importance of Ultraviolet A Protection in Sunscreens

The use of sunscreens is recommended to limit the impact of sun exposure on the skin. The objective of this study was to examine the relationship between sunscreen sales and melanoma in 4 different countries with diverse sunscreen regulations. Data from publicly available databases were examined for Sweden, England, Australia, and the USA from 1999 to 2018. The association between incidence of melanoma and sunscreen sales was estimated using a generalized estimating equation, and modelling was used to predict melanoma cases. Incidence of melanoma was positively associated with sunscreen sales in England, Australia, and the USA, and negatively associated with sunscreen sales in Sweden. Growth rates in melanoma cases of 0.42%, 16.7%, 19.1% and 12.2% were predicted for Sweden, England, Australia, and the USA, respectively. The differences observed between England, Australia, and the USA, on the one hand, and Sweden, on the other hand, are consistent with the adoption of strong regulations requiring the use of ultraviolet A blocking agents in sunscreens.

Association of MDM2 T309G (rs2279744) Polymorphism and Expression Changes With Risk of Prostate Cancer in the Slovak Population

BACKGROUND/AIM

The aim of this study was to evaluate the relationship between MDM2 T309G polymorphism and prostate cancer risk in the Slovak population and the association of this polymorphism with MDM2 expression and clinicopathological features.

MATERIALS AND METHODS

The MDM2 T309G polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in 506 prostate cancer patients and 592 controls. Quantitative real-time (RT)-PCR and western blot analysis were applied to examine MDM2 expression in 47 prostate cancer tissues and 43 benign prostatic hyperplasia (BPH) tissues.

RESULTS

A decreased risk of prostate cancer in men carrying the GG genotype in comparison with the TT genotype was found. A decrease in the relative MDM2 mRNA and protein levels was found in prostate cancer tissues among patients with the MDM2 GG genotype.

CONCLUSION

There is a potentially protective effect of the MDM2 GG genotype on the risk of prostate cancer in the Slovak male population.

Homocysteine and Mitochondria in Cardiovascular and Cerebrovascular Systems

Elevated concentration of homocysteine (Hcy) in the blood plasma, hyperhomocysteinemia (HHcy), has been implicated in various disorders, including cardiovascular and neurodegenerative diseases. Accumulating evidence indicates that pathophysiology of these diseases is linked with mitochondrial dysfunction. In this review, we discuss the current knowledge concerning the effects of HHcy on mitochondrial homeostasis, including energy metabolism, mitochondrial apoptotic pathway, and mitochondrial dynamics. The recent studies suggest that the interaction between Hcy and mitochondria is complex, and reactive oxygen species (ROS) are possible mediators of Hcy effects. We focus on mechanisms contributing to HHcy-associated oxidative stress, such as sources of ROS generation and alterations in antioxidant defense resulting from altered gene expression and post-translational modifications of proteins. Moreover, we discuss some recent findings suggesting that HHcy may have beneficial effects on mitochondrial ROS homeostasis and antioxidant defense. A better understanding of complex mechanisms through which Hcy affects mitochondrial functions could contribute to the development of more specific therapeutic strategies targeted at HHcy-associated disorders.

The impact of discontinuing contact precautions for multidrug resistant organisms at a less than 400-bed level II teaching hospital and a community hospital: A 3-month pilot study

BACKGROUND

The impact of discontinuing contact precautions (CPs) for patients with select multidrug-resistant organisms on bacteremia infection rates was evaluated in this quality improvement project.

METHODS

The removal of use of CPs, with increased focus on standard precautions, for all patients with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) colonization/infection was piloted via a quality improvement project over a 3-month period.

RESULTS

CP was discontinued in December 2018. Comparing 3 months pre- and postchange, the overall incidence density rate decreased for hospital-onset (HO) laboratory-identified (LabID) MRSA bacteremia (0.07 vs 0.02; P = .52), whereas HO LabID VRE bacteremia rates remained the same (0.00 vs 0.00). Overall estimated financial savings, including personal protective equipment ($15,375) and staff time ($17,165), was $32,540 for the project period, with annualized estimated savings of $130,160.

CONCLUSIONS

In this pilot study evaluating the discontinuance of CPs, there was no evidence of an increase in HO MRSA or VRE LabID bacteremia incidence density rates. This practice change may be safely implemented at similar health care facilities.

Exhaled Volatile Organic Compounds Precedes Pulmonary Injury in a Swine Pulmonary Oxygen Toxicity Model

Purpose

Inspiring high partial pressure of oxygen (FiO₂ > 0.6) for a prolonged duration can lead to lung damage termed pulmonary oxygen toxicity (PO₂T). While current practice is to limit oxygen exposure, there are clinical and military scenarios where higher FiO₂ levels and partial pressures of oxygen are required. The purpose of this study is to develop a non-invasive breath-based biomarker to detect PO₂T prior to the onset of clinical symptoms.

Methods

Male Yorkshire swine (20–30 kg) were placed into custom airtight runs and randomized to air (0.209 FiO₂, n = 12) or oxygen (>0.95 FiO₂, n = 10) for 72 h. Breath samples, arterial blood gases, and vital signs were assessed every 12 h. After 72 h of exposure, animals were euthanized and the lungs processed for histology and wet-dry ratios.

Results

Swine exposed to hyperoxia developed pulmonary injury consistent with PO₂T. Histology of oxygen-exposed swine showed pulmonary lymphatic congestion, epithelial sloughing, and neutrophil transmigration. Pulmonary injury was also evidenced by increased interstitial edema and a decreased PaO₂/FiO₂ ratio in the oxygen group when compared to the air control group. Breath volatile organic compound (VOC) sample analysis identified six VOCs that were combined into an algorithm which generated a breath score predicting PO₂T with a ROC/AUC curve of 0.72 defined as a of PaO₂/FiO₂ ratio less than 350 mmHg.

Conclusion

Exposing swine to 72 h of hyperoxia induced a pulmonary injury consistent with human clinical endpoints of PO₂T. VOC analysis identified six VOCs in exhaled breath that preceded PO₂T. Results show promise that a simple, non-invasive breath test could potentially predict the risk of pulmonary injury in humans exposed to high partial pressures of oxygen.

A comparison of albumin removal procedures for proteomic analysis of blood plasma

Blood biomarkers are usually present in low concentration and can be masked by the high-abundance proteins, of which albumin is the predominant one. The purpose of this study was to compare four different albumin removal methods compatible with in-gel based proteomics, applicable for plasma, without requiring specific techniques and high financial input. Plasma underwent albumin depletion with ultrafiltration device Amicon Ultra, commercial ProteoPrep Blue Albumin and IgG Depletion Kit, acetonitrile precipitation method and precipitation with acetonitrile-methanol protocol. All samples were evaluated by 1-D and 2-D gel electrophoresis with subsequent mass spectrometry protein identification. Two of the tested methods (ProteoPrep BlueKit and acetonitrile-methanol precipitation) maintained sufficient protein content for further in-gel analyses. Their 2-D protein profiles were distinctively separated and overlapped with protein profile of crude plasma. Protein spot count showed significant increase in protein spots, compared to crude plasma, only with acetonitrile-methanol precipitation method. Precipitation with acetonitrile-methanol method significantly increased number of protein spots on 2-D protein profile and improved score of mass spectrometry identification. However, albumin was still present and found in number of protein spots.

Global brain ischemia in rats is associated with mitochondrial release and downregulation of Mfn2 in the cerebral cortex, but not the hippocampus

Mitochondria are crucial for neuronal cell survival and death through their functions in ATP production and the intrinsic pathway of apoptosis. Mitochondrial dysfunction is considered to play a central role in several serious human diseases, including neurodegenerative diseases, such as Parkinson's and Alzheimer's disease and ischemic neurodegeneration. The aim of the present study was to investigate the impact of transient global brain ischemia on the expression of selected proteins involved in mitochondrial dynamics and mitochondria‑associated membranes. The main foci of interest were the proteins mitofusin 2 (Mfn2), dynamin‑related protein 1 (DRP1), voltage‑dependent anion‑selective channel 1 (VDAC1) and glucose‑regulated protein 75 (GRP75). Western blot analysis of total cell extracts and mitochondria isolated from either the cerebral cortex or hippocampus of experimental animals was performed. In addition, Mfn2 was localized intracellularly by laser scanning confocal microscopy. It was demonstrated that 15‑min ischemia, or 15‑min ischemia followed by 1, 3, 24 or 72 h of reperfusion, was associated with a marked decrease of the Mfn2 protein in mitochondria isolated from the cerebral cortex, but not in hippocampal mitochondria. Moreover, a translocation of the Mfn2 protein to the cytoplasm was documented immediately after global brain ischemia in the neurons of the cerebral cortex by laser scanning confocal microscopy. Mfn2 translocation was followed by decreased expression of Mfn2 during reperfusion. Markedly elevated levels of the VDAC1 protein were also documented in total cell extracts isolated from the hippocampus of rats after 15 min of global brain ischemia followed by 3 h of reperfusion, and from the cerebral cortex of rats after 15 min of global brain ischemia followed by 72 h of reperfusion. The mitochondrial Mfn2 release observed during the early stages of reperfusion may thus represent an important mechanism of mitochondrial dysfunction associated with neuronal dysfunction or death induced by global brain ischemia.

Standardisierter Computer-basiert-organisierter Report des EEG (SCORE) – Eine strukturierende Form der EEG-Befundung

Eine 2013 von der „International Federation of Clinical Neurophysiology“ gegründete Taskforce hat eine international konsensfähige EEG-Terminologie entwickelt. Im Folgenden soll das Resultat – die 2. Version des Standardized Computer-based Organized Reporting of EEG (SCORE) - vorgestellt werden. Die Terminologie wurde im Rahmen eines Softwarepaketes (SCORE-EEG) in der klinischen Praxis an über 12.000 EEGs getestet. Die Auswahl der Begriffe ist kontextabhängig: die initiale Auswahl bestimmt, welche weiteren Auswahlmöglichkeiten zur Verfügung stehen. Im Verlauf wird automatisch ein Befund erstellt und dessen Einzelmerkmale in eine Datenbank eingespeist. SCORE verfügt über Module spezifisch für die Befundung epileptischer Anfälle, sowie charakteristischer neonataler und intensivmedizinische EEG-Merkmale. SCORE ist nicht nur ein nützliches Werkzeug im ambulanten, klinischen und wissenschaftlichen Setting, es erleichtert auch Qualitätssicherung, Datenaustausch und die EEG-Aus und Weiterbildung.

Proteomic analysis of mitochondrial proteins in the guinea pig heart following long-term normobaric hyperoxia

Normobaric hyperoxia is applied for the treatment of a wide variety of diseases and clinical conditions related to ischemia or hypoxia, but it can increase the risk of tissue damage and its efficiency is controversial. In the present study, we analyzed cardiac mitochondrial proteome derived from guinea pigs after 60 h exposure to 100% molecular oxygen (NBO) or O₂ enriched with oxygen cation (NBO+). Two-dimensional gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry identified twenty-two different proteins (among them ten nonmitochondrial) that were overexpressed in NBO and/or NBO+ group. Identified proteins were mainly involved in cellular energy metabolism (tricarboxylic acid cycle, oxidative phosphorylation, glycolysis), cardioprotection against stress, control of mitochondrial function, muscle contraction, and oxygen transport. These findings support the viewpoint that hyperoxia is associated with cellular stress and suggest complex adaptive responses which probably contribute to maintain or improve intracellular ATP levels and contractile function of cardiomyocytes. In addition, the results suggest that hyperoxia-induced cellular stress may be partially attenuated by utilization of NBO+ treatment.

Effect of maturation on the resistance of rat hearts against ischemia. Study of potential molecular mechanisms

Reduced tolerance to ischemia/reperfusion (IR) injury has been shown in elder human and animal hearts, however, the onset of this unfavorable phenotype and cellular mechanisms behind remain unknown. Moreover, aging may interfere with the mechanisms of innate cardioprotection (preconditioning, PC) and cause defects in protective cell signaling. We studied the changes in myocardial function and response to ischemia, as well as selected proteins involved in "pro-survival" pathways in the hearts from juvenile (1.5 months), younger adult (3 months) and mature adult (6 months) male Wistar rats. In Langendorff-perfused hearts exposed to 30-min ischemia/2-h reperfusion with or without prior PC (one cycle of 5-min ischemia/5-min reperfusion), we measured occurrence of reperfusion-induced arrhythmias, recovery of contractile function (left ventricular developed pressure, LVDP, in % of pre-ischemic values), and size of infarction (IS, in % of area at risk size, TTC staining and computerized planimetry). In parallel groups, LV tissue was sampled for the detection of protein levels (WB) of Akt kinase (an effector of PI3-kinase), phosphorylated (activated) Akt (p-Akt), its target endothelial NO synthase (eNOS) and protein kinase Cepsilon (PKCepsilon) as components of "pro-survival" cascades. Maturation did not affect heart function, however, it impaired cardiac response to lethal IR injury (increased IS) and promoted arrhythmogenesis. PC reduced the occurrence of malignant arrhythmias, IS and improved LVDP recovery in the younger animals, while its efficacy was attenuated in the mature adults. Loss of PC protection was associated with age-dependent reduced Akt phosphorylation and levels of eNOS and PKCepsilon in the hearts of mature animals compared with the younger ones, as well as with a failure of PC to upregulate these proteins. Aging-related alterations in myocardial response to ischemia may be caused by dysfunction of proteins involved in protective cell signaling that may occur already during the process of maturation.

Effect of aging on formation of reactive oxygen species by mitochondria of rat heart

Mitochondrial electron transport chain is thought to be a major source of reactive oxygen species (ROS) during aging. However, this view is supported mainly by accumulation of mitochondrial oxidative damage with age and the exact sites of ROS formation remains unknown. In the present study, we measured rate of ROS formation using 2',7'-dichlorofluorescein (DCF) probe in cardiac mitochondria from adult (6-month-old), old (15-month-old) and senescent (26-month-old) rats. In mitochondria oxidizing complex II substrate, succinate, the rate of ROS formation progressively increased with age. In the presence of complex I inhibitor rotenone or complex III inhibitor antimycin A, the rate ROS formation significantly decreased, but even the combination of inhibitors could not fully prevent generation of ROS. Age-dependent increase of ROS formation was accompanied by a loss of thiol groups, tryptophan degradation and increased lipid peroxidation. These data suggest that in addition to complex I and complex II other mitochondrial sites can contribute to accelerated ROS generation and oxidative damage during aging.

Effect of normobaric oxygen treatment on oxidative stress and enzyme activities in guinea pig heart

Normobaric oxygen (NBO) therapy is commonly applied for the treatment of various diseases, including myocardial infarctions, but its effectiveness is controversial. Potential adverse effects of hyperoxia are related to excessive formation of free radicals. In the present study we examined the effect of 60-h NBO treatment on lipid peroxidation (LPO), activity of manganese superoxide dismutase (Mn-SOD) and mitochondrial enzymes of energy metabolism in guinea pig heart. NBO treatment resulted in significant accumulation of thiobarbituric acid reactive substances and loss of Mn-SOD activity despite slight elevation of Mn-SOD protein content. Activity of electron transport chain complex III decreased significantly, while activity of complex IV was slightly elevated and citrate synthase was unchanged. LPO, inhibition of Mn-SOD and complex III activities were more pronounced when inhaled oxygen was partially enriched with superoxide radical. In contrast, when O(2) was enriched with oxygen cation (O(2)●+), LPO and loss of Mn-SOD activity were prevented. Complex III activity in the O(2)●+-treated group remained depressed but activities of complex IV and citrate synthase were elevated. These data suggest that NBO treatment is associated with myocardial oxidative damage and attenuation of antioxidant defense, but these adverse effects can be partially attenuated by inhalation of O(2) enriched with oxygen cation.

Why mitochondria are excellent targets for cancer therapy

New insights into cancer cells - specific biological pathways are urgently needed to promote development of exactly targeted therapeutics. The role of oncoproteins and tumor suppressor proteins in proliferative signaling, cell cycle regulation and altered adhesion is well established. Chemicals, viruses and radiation are also generally accepted as agents that commonly induce mutations in genes encoding these cancer-inducing proteins, thereby giving rise to cancer. More recent evidence indicates the importance of two additional key factors imposed on proliferating cells - hypoxia and/or lack of glucose. These two additional triggers can initiate and promote the process of malignant transformation, when a low percentage of cells escape cellular senescence. Disregulated cell proliferation leads to formation of cellular masses that extend beyond the resting vasculature, resulting in oxygen and nutrient deprivation. Resulting hypoxia triggers a number of critical adaptations that enable cancer cell survival. The process of apoptosis is suppressed and glucose metabolism is altered. Recent investigations suggest that oxygen depletion stimulates mitochondria to compensate increased reactive oxygen species (ROS). It activates signaling pathways, such as hypoxia-inducible factor 1, that promote cancer cell survival and tumor growth. During the last decade, mitochondria have become key organelles involved in chemotherapy-induced apoptosis. Therefore, the relationship between mitochondria, ROS signaling and activation of survival pathways under hypoxic conditions has been the subject of increased study. Insights into mechanisms involved in ROS signaling may offer novel ways to facilitate discovery of cancer-specific therapies.

Response of secretory pathways Ca(2+) ATPase gene expression to hyperhomocysteinemia and/or ischemic preconditioning in rat cerebral cortex and hippocampus

The study determines whether hyperhomocysteinemia (risk factor of brain ischemia) alone or in combination with ischemic preconditioning (IPC) affects the ischemia-induced changes in gene expression of secretory pathways Ca(2+)-ATPase (SPCA1). Hyperhomocysteinemia was induced by subcutaneous administration of homocysteine (Hcy; 0.45 µmol/g body weight) twice a day at 8 h intervals for 14 days. Rats were preconditioned by 5 min ischemia and 2 days later, 15 min of global forebrain ischemia was induced by four vessel occlusion. We observed that hyperhomocysteinemia significantly decreased the level of SPCA1 mRNA in the cortex. Pre-ischemic challenge was noticeable in both brain areas. In the cortex, pre-ischemia in Hcy group led to the abrupt stimulation of the mRNA expression by 249% within the Hcy ischemic group and by 321% in the Hcy control. Values further exceeded those observed in the naive control. In the hippocampus, the differences between naive and Hcy groups were not observed. IPC initiated elevation of mRNA expression to 159% (p < 0.05) of control with Hcy and to 131% (p < 0.01) of ischemia with Hcy, respectively. Documented response of SPCA gene to IPC in hyperhomocysteinemic group might suggest a correlation of SPCA expression consistent with the role of cross-talks between intracellular Ca(2+) stores including secretory pathways in the tolerance phenomenon.

GFAP mutations, age at onset, and clinical subtypes in Alexander disease

OBJECTIVE

To characterize Alexander disease (AxD) phenotypes and determine correlations with age at onset (AAO) and genetic mutation. AxD is an astrogliopathy usually characterized on MRI by leukodystrophy and caused by glial fibrillary acidic protein (GFAP) mutations.

METHODS

We present 30 new cases of AxD and reviewed 185 previously reported cases. We conducted Wilcoxon rank sum tests to identify variables scaling with AAO, survival analysis to identify predictors of mortality, and χ(2) tests to assess the effects of common GFAP mutations. Finally, we performed latent class analysis (LCA) to statistically define AxD subtypes.

RESULTS

LCA identified 2 classes of AxD. Type I is characterized by early onset, seizures, macrocephaly, motor delay, encephalopathy, failure to thrive, paroxysmal deterioration, and typical MRI features. Type II is characterized by later onset, autonomic dysfunction, ocular movement abnormalities, bulbar symptoms, and atypical MRI features. Survival analysis predicted a nearly 2-fold increase in mortality among patients with type I AxD relative to those with type II. R79 and R239 GFAP mutations were most common (16.6% and 20.3% of all cases, respectively). These common mutations predicted distinct clinical outcomes, with R239 predicting the most aggressive course.

CONCLUSIONS

AAO and the GFAP mutation site are important clinical predictors in AxD, with clear correlations to defined patterns of phenotypic expression. We propose revised AxD subtypes, type I and type II, based on analysis of statistically defined patient groups.

Thermal styling: efficacy, convenience, damage tradeoffs

We introduce a simple method to explore the efficacy of thermal styling, By using a temperature gradient curling iron we rapidly explore a range of thermal treatment conditions. The thermodynamic literature on the glass transition in keratin fibers explains the surprisingly limited role of elevated temperature in improvements in the efficacy of holding the styled curvature of the fibers. The onset of damage, however, is strongly temperature dependent. This combination of measurements of damage and efficacy shows the range of conditions over which thermal protection products must be functional.

Effects of long-term oxygen treatment on alpha-ketoglutarate dehydrogenase activity and oxidative modifications in mitochondria of the guinea pig heart

OBJECTIVE

Oxygen therapy is used for the treatment of various diseases, but prolonged exposure to high concentrations of O(2) is also associated with formation of free radicals and oxidative damage.

METHODS

In the present study we compared alpha-ketoglutarate dehydrogenase (KGDH) activity and mitochondrial oxidative damage in the hearts of guinea pigs after long-term (17 and 60 h) oxygenation with 100% normobaric O(2) and with partially negatively (O(2 neg)) or positively (O(2 posit)) ionized oxygen.

RESULTS

Inhalation of O(2) led to significant loss in KGDH activity and thiol group content and accumulation of bityrosines. Inhalation of O(2 neg) was accompanied by more pronounced KGDH inhibition, possibly due to additional formation of protein-lipid conjugates. In contrast, O(2 posit) prevented loss in KGDH activity and diminished mitochondrial oxidative damage.

CONCLUSIONS

These findings suggest that oxygen treatment is associated with impairment of heart energy metabolism and support the view that inhalation of O(2 posit) optimizes the beneficial effects of oxygen therapy.

Myocardial Ca2+ handling and cell-to-cell coupling, key factors in prevention of sudden cardiac deathThis article is one of a selection of papers published in a special issue on Advances in Cardiovascular Research

Using whole-heart preparations, we tested our hypothesis that Ca2+ handling is closely related to cell-to-cell coupling at the gap junctions and that both are critical for the development and particularly the termination of ventricular fibrillation (VF) and hence the prevention of sudden arrhythmic death. Intracellular free calcium concentration ([Ca2+]i), ECG, and left ventricular pressure were continuously monitored in isolated guinea pig hearts before and during development of low K+-induced sustained VF and during its conversion into sinus rhythm facilitated by stobadine. We also examined myocardial ultrastructure to detect cell-to-cell coupling alterations. We demonstrated that VF occurrence was preceded by a 55.9% ± 6.2% increase in diastolic [Ca2+]i, which was associated with subcellular alterations indicating Ca2+ overload of the cardiomyocytes and disorders in coupling among the cells. Moreover, VF itself further increased [Ca2+]i by 58.2% ± 3.4% and deteriorated subcellular and cell-to-cell coupling abnormalities that were heterogeneously distributed throughout the myocardium. In contrast, termination of VF and its conversion into sinus rhythm was marked by restoration of basal [Ca2+]i, resulting in recovery of intercellular coupling linked with synchronous contraction. Furthermore, we have shown that hearts exhibiting lower SERCA2a (sarcoplasmic reticulum Ca2+-ATPase) activity and abnormal intercellular coupling (as in older guinea pigs) are more prone to develop Ca2+ overload associated with cell-to-cell uncoupling than hearts with higher SERCA2a activity (as in young guinea pigs). Consequently, young animals are better able to terminate VF spontaneously. These findings indicate the crucial role of Ca2+ handling in relation to cell-to-cell coupling in both the occurrence and termination of malignant arrhythmia.

A randomized trial comparing the efficacy and safety of imiglucerase (Cerezyme) infusions every 4 weeks versus every 2 weeks in the maintenance therapy of adult patients with Gaucher disease type 1

Imiglucerase (Cerezyme) has been the standard of care for treatment of Gaucher disease, a lysosomal storage disorder resulting from deficiency of glucocerebrosidase, since its approval in 1994. Infusions are typically given once every 2 weeks. However, many patients have expressed a desire for less frequent infusions as a matter of convenience. This clinical study assessed the safety and efficacy of intravenous imiglucerase infused once every 4 weeks (Q4) compared to once every 2 weeks (Q2) at the same total monthly dose in adult patients with clinically stable Gaucher disease type 1 (GD1). This was a 24-month, open-label, randomized, Phase 4, dose-frequency study conducted in 25 centers worldwide. Patients receiving imiglucerase were randomized to receive their monthly dose biweekly (n=33) or every 4 weeks (n=62). Changes from baseline in hemoglobin, platelets, liver and spleen volumes, bone crisis, and bone disease comprised a predefined composite endpoint; achievement or maintenance of established Gaucher disease therapeutic goals comprised a secondary endpoint. Sixty-three percent of Q4- and 81% of Q2-treated patients met the composite endpoint at Month 24; 89% of Q4- and 100% of Q2-treated patients met the therapeutic goals-based endpoint. The frequency of related adverse events was comparable between treatment groups. This study suggests that with comprehensive monitoring, a Q4 imiglucerase infusion regimen may be a safe and effective treatment option for the majority of clinically stable adult patients with GD1 but may not be appropriate for all GD1 patients. Continued monitoring in patients treated with Q4 dosing is required to assess long-term effectiveness.

Alterations induced by ischemic preconditioning on secretory pathways Ca2+-ATPase (SPCA) gene expression and oxidative damage after global cerebral ischemia/reperfusion in rats

Ischemic preconditioning (IPC) represents the phenomenon of CNC adaptation, which results in increased tolerance of CNS to lethal ischemia. Brain ischemia/reperfusion (IRI) initiates a catastrophic cascade in which many subcellular organelles play an important role. The Golgi apparatus, which is a part of secretory pathways (SP), represents the Ca(2+) store and regulates secretion of proteins for growth/reorganization of neuronal circuit by secretory Ca(2+)ATPases (SPCA1). The purpose of this study is to evaluate the effect of IRI and preconditioning on SPCA1 gene expression and oxidative damage after 4-vessel occlusion for 15 min and after being exposed to different reperfusion periods. Rats were preconditioned by 5 min of sub-lethal ischemia and 2 days later, 15 min of lethal ischemia was induced. Our experiments conclusively showed IRI-induced depression of SPCA activity and lipo- and protein oxidation in rat hippocampal membranes. IRI also activates the induction of SPCA1 gene expression in later reperfusion periods. IPC partially suppresses lipo- and protein oxidation in hippocampal membranes and leads to partiall rovery of the ischemic-induced depression of SPCA activity. In addition, IPC initiates earlier cellular response to the injury by the significant elevation of mRNA expression to 142% comparing to 1 h of corresponding reperfusion and to 11% comparing to 24 h of corresponding reperfusion, respectively. Similar patterns were observed on the translational level by Western blot analysis. Our results indicate the specific SPCA1 expression pattern in ischemic hippocampus. It also shows that the SPCA expression and the post-translational changes induced by ischemia are modulated by the IPC. This might serve to understand the molecular mechanisms involved in the structural integrity and function of the SP after ischemic challenge. It also suggests that there is a correlation of SPCA function with the role of SP in the response to pre-ischemic challenge.

Mitochondrial calcium transport and mitochondrial dysfunction after global brain ischemia in rat hippocampus

Here we report effect of ischemia-reperfusion on mitochondrial Ca2+ uptake and activity of complexes I and IV in rat hippocampus. By performing 4-vessel occlusion model of global brain ischemia, we observed that 15 min ischemia led to significant decrease of mitochondrial capacity to accumulate Ca2+ to 80.8% of control whereas rate of Ca2+ uptake was not significantly changed. Reperfusion did not significantly change mitochondrial Ca2+ transport. Ischemia induced progressive inhibition of complex I, affecting final electron transfer to decylubiquinone. Minimal activity of complex I was observed 24 h after ischemia (63% of control). Inhibition of complex IV activity to 80.6% of control was observed 1 h after ischemia. To explain the discrepancy between impact of ischemia on rate of Ca2+ uptake and activities of both complexes, we performed titration experiments to study relationship between inhibition of particular complex and generation of mitochondrial transmembrane potential (DeltaPsi(m)). Generation of a threshold curves showed that complex I and IV activities must be decreased by approximately 40, and 60%, respectively, before significant decline in DeltaPsi(m) was documented. Thus, mitochondrial Ca2+ uptake was not significantly affected by ischemia-reperfusion, apparently due to excess capacity of the complexes I and IV. Inhibition of complex I is favourable of reactive oxygen species (ROS) generation. Maximal oxidative modification of membrane proteins was documented 1 h after ischemia. Although enhanced formation of ROS might contribute to neuronal injury, depressed activities of complex I and IV together with unaltered rate of Ca2+ uptake are conditions favourable of initiation of other cell degenerative pathways like opening of mitochondrial permeability transition pore or apoptosis initiation, and might represent important mechanism of ischemic damage to neurones.

Oxidative alternations in rat heart homogenate and mitochondria during ageing

Our understanding of the role played by reactive oxygen and nitrogen species in disease pathology and ageing is still insufficient. Reactive oxygen species and reactive nitrogen species can initiate protein and lipid oxidative damage that may be the most important contribution to ageing and age-related heart diseases. In the present study, we investigated the effect of ageing on oxidative damage of protein amino acid residues and lipids in heart homogenate and mitochondria of 4- and 26-month-old Wistar rats. Levels of dityrosine and levels of lysine conjugates increased in heart homogenate during ageing, although levels of conjugated dienes did not change. We observed significantly oxidative modification of tryptophan in heart mitochondria and increased levels of dityrosine with advancing age. However, levels of lysine conjugates, conjugated dienes as well as relative level of cytochrome c oxidase were unchanged in heart mitochondria during ageing. The results of this study suggest a different mechanism of oxidative modification in heart compartments during ageing and moreover, mitochondria and other cellular compartments are targets for oxidative modifications.

Improvement of bone disease by imiglucerase (Cerezyme) therapy in patients with skeletal manifestations of type 1 Gaucher disease: results of a 48-month longitudinal cohort study

Sims KB, Pastores GM, Weinreb NJ, Barranger J, Rosenbloom BE, Packman S, Kaplan P, Mankin H, Xavier R, Angell J, Fitzpatrick MA, Rosenthal D. Improvement of bone disease by imiglucerase (Cerezyme) therapy in patients with skeletal manifestations of type 1 Gaucher disease: results of a 48-month longitudinal cohort study. Clin Genet 2008: 73: 430–440. © Blackwell Munksgaard, 2008

Progressive skeletal disease accounts for some of the most debilitating complications of type 1 Gaucher disease. In this 48-month, prospective, non-randomized, open-label study of the effect of enzyme replacement therapy on bone response, 33 imiglucerase-naïve patients (median age 43 years with one or more skeletal manifestations such as osteopenia, history of bone crisis, or other documented bone pathology) received imiglucerase 60 U/kg/2 weeks. Substantial improvements were observed in bone pain (BP), bone crises (BC), and bone mineral density (BMD). Improvements in BP were observed at 3 months (p < 0.001 vs baseline) and continued progressively throughout the study, with 39% of patients reporting pain at 48 months vs 73% at baseline. Eleven of the 13 patients with a pre-treatment history of BC had no recurrences. Biochemical markers for bone formation increased; markers for bone resorption decreased. Steady improvement of spine and femoral neck BMD, measured using dual-energy X-ray absorptiometry was noted. Mean Z score for spine increased from −0.72 ± 1.302 at baseline to near-normal levels (−0.09 ± 1.503) by month 48 (p = 0.042) and for femoral neck from −0.59 ± 1.352 to −0.17 ± 1.206 (p = 0.035) at month 36. This increase was sustained at 48 months. With imiglucerase treatment, patients should anticipate resolution of BC, rapid improvement in BP, increases in BMD, and decreased skeletal complications.

Ischemia-reperfusion induces inhibition of mitochondrial protein synthesis and cytochrome c oxidase activity in rat hippocampus

Dysfunction of mitochondria induced by ischemia is considered to be a key event triggering neuronal cell death after brain ischemia. Here we report the effect of ischemia-reperfusion on mitochondrial protein synthesis and activity of cytochrome c oxidase (EC 1.9.3.1, COX). By performing 4-vessel occlusion model of global brain ischemia, we have observed that 15 min of global ischemia led to the inhibition of COX subunit I (COXI) synthesis to 56 % of control. After 1, 3 and 24 h of reperfusion, COXI synthesis was inhibited to 46, 50 and 72 % of control, respectively. Depressed synthesis of COXI was not a result of either diminished transcription of COXI gene or increased proteolytic degradation of COXI, since both Northern hybridization and Western blotting did not show significant changes in COXI mRNA and protein level. Thus, ischemia-reperfusion affects directly mitochondrial translation machinery. In addition, ischemia in duration of 15 min and consequent 1, 3 and 24 h of reperfusion led to the inhibition of COX activity to 90.3, 80.3, 81.9 and 83.5 % of control, respectively. Based on our data, we suggest that inhibition of COX activity is rather caused by ischemia-induced modification of COX polypeptides than by inhibition of mitochondrial translation.

Oxidative modifications of cardiac mitochondria and inhibition of cytochrome c oxidase activity by 4-hydroxynonenal

4-hydroxynonenal (HNE) is a highly toxic product of lipid peroxidation (LPO). Its role in the inhibition of cytochrome c oxidase activity and oxidative modifications of mitochondrial lipids and proteins were investigated. The exposure of mitochondria isolated from rat heart to HNE resulted in a time- and concentration-dependent inhibition of cytochrome c oxidase activity with an IC50 value of 8.3 +/- 1.0 microM. Immunoprecipitation-Western blot analysis showed the formation of HNE adducts with cytochrome c oxidase subunit I. The loss of cytochrome c oxidase activity was also accompanied by reduced thiol group content and increased HNE-lysine fluorescence. Furthermore, there was a marked increase in conjugated diene formation indicating LPO induction by HNE. Fluorescence measurements revealed the formation of bityrosines and increased surface hydrophobicity of HNE-treated mitochondrial membranes. Superoxide dismutase + catalase and the HO* radical scavenger mannitol partially prevented inhibition of cytochrome c oxidase activity and formation of bityrosines. These findings suggest that HNE induces formation of reactive oxygen species and its damaging effect on mitochondria involves both formation of HNE-protein adducts and oxidation of membrane lipids and proteins by free radicals.

Effect of ischemic preconditioning on mitochondrial dysfunction and mitochondrial p53 translocation after transient global cerebral ischemia in rats

Transient global brain ischemia induces dysfunctions of mitochondria including disturbance in mitochondrial protein synthesis and inhibition of respiratory chain complexes. Due to capacity of mitochondria to release apoptogenic proteins, ischemia-induced mitochondrial dysfunction is considered to be a key event coupling cerebral blood flow arrest to neuronal cell death. Ischemic preconditioning (IPC) represents an important phenomenon of adaptation of central nervous system (CNS) to sub-lethal short-term ischemia, which results in increased tolerance of CNS to the lethal ischemia. In this study we have determined the effect of ischemic preconditioning on ischemia/reperfusion-associated inhibition of mitochondrial protein synthesis and activity of mitochondrial respiratory chain complexes I and IV in the hippocampus of rats. Global brain ischemia was induced by 4-vessel occlusion in duration of 15 min. Rats were preconditioned by 5 min of sub-lethal ischemia and 2 days later, 15 min of lethal ischemia was induced. Our results showed that IPC affects ischemia-induced dysfunction of hippocampal mitochondria in two different ways. Repression of mitochondrial translation induced during reperfusion of the ischemic brain is significantly attenuated by IPC. Slight protective effect of IPC was documented for complex IV, but not for complex I. Despite this, protective effect of IPC on ischemia/reperfusion-associated changes in integrity of mitochondrial membrane and membrane proteins were observed. Since IPC exhibited also inhibitory effect on translocation of p53 to mitochondria, our results indicate that IPC affects downstream processes connecting mitochondrial dysfunction to neuronal cell death.

Modulation of expression of the sigma receptors in the heart of rat and mouse in normal and pathological conditions

The aim of the present work was to study the effect of various stressors (hypoxia, cold, immobilization) on the gene expression of sigma receptors in the left ventricles of rat heart. We have clearly shown that gene expression of sigma receptors is upregulated by strong stress stimuli, such as immobilization and/or hypoxia. Nevertheless, cold as a milder stressor has no effect on sigma receptor's mRNA levels. Signalling cascade of sigma receptors is dependent on IP(3) receptors, since silencing of both, type 1 and 2 IP(3) receptors resulted in decreased mRNA levels of sigma receptors. Physiological relevance of sigma receptors in the heart is not clear yet. Nevertheless, based on the already published data we can assume that sigma receptors might participate in contractile responses in cardiomyocytes.