Maria Chomova

Ischemia-Induced Inhibition of Mitochondrial Complex I in Rat Brain: Effect of Permeabilization Method and Electron Acceptor

In this study we have examined the effect of global brain ischemia/reperfusion on biochemical properties of the mitochondrial respiratory complex I (CI) in rat hippocampus and cortex. Since the inner mitochondrial membrane forms the permeability barrier for NADH, the methodology of enzymatic activity determinations employs membrane permeabilization methods. This action affects the basic character of electrostatic and hydrophobic interactions inside the membrane and might influence functional properties of membrane embedded proteins. Therefore we have performed the comparative analysis of two permeabilization methods (sonication, detergent) and their impact on CI enzymatic activities under global brain ischemic-reperfusion conditions. We have observed that ischemia led to significant decrease of CI activities using both permeabilization methods in both brain areas. However, significant differencies in enzymatic activities were registered during reperfusion intervals according to used permeabilization method. We have also tested the effect of electron acceptors (decylubiquinone, potassium ferricyanide, nitrotetrazolium blue) on CI activities during I/R. Based on our results we assume that the critical site where ischemia affects CI activities is electron transfer to electron acceptor. Further, the observed mitochondrial dysfunction was analyzed by means of one and 2-dimensional BN PAGE/SDS PAGE with the focus on 3-nitrotyrosine immunodetection as a marker of oxidative damage to proteins. Add to this, initialization of p53 mitochondrial apoptosis through p53, Bax, Bcl-XL proteins and a possible involvement of GRIM-19, the CI structural subunit, in apoptotic processes were also studied.

Look into brain energy crisis and membrane pathophysiology in ischemia and reperfusion

Abstract In an ischemic environment, brain tissue responds to oxygen deprivation with the initiation of rapid changes in bioenergetic metabolism to ensure ion and metabolic homeostasis. At the same time, the accelerated cleavage of membrane phospholipids changes membrane composition and increases free fatty acid concentration. Phospholipid breakdown also generates specific messengers that participate in signaling cascades that can either promote neuronal protection or cause injury. The net impact of signaling events affects the final outcome of the stroke. While reoxygenation is a life-saving intervention, it can exacerbate brain damage. Although compromised energy metabolism is restored shortly after reperfusion, alterations in membrane phospholipid composition with subsequent accumulation of lipid oxoderivates are neurotoxic, causing oxidative stress and ischemia–reperfusion (IR) injury. Thus, plasma and mitochondrial membranes are the first responders as well as mediators of IR-induced stress signals. In this review, we focus on ischemia-induced changes in brain energy metabolism and membrane functions as the causal agents of cell stress responses upon reoxygenation. The first part of the review deals with the specificities of neuronal bioenergetics during IR and their impact on metabolic processes. The second part is concentrated on involvement of both plasma and mitochondrial membranes in the production of messengers which can modulate neuroprotective pathways or participate in oxidative/electrophilic stress responses. Although the etiology of IR injury is multifactorial, deciphering the role of membrane and membrane-associated processes in brain damage will uncover new therapeutic agents with the ability to stabilize neuronal membranes and modulate their responses in favor of prosurvival pathways.

Oxidative Stress Markers and Their Dynamic Changes in Patients after Acute Ischemic Stroke

We have focused on determining the range of oxidative stress biomarkers and their dynamic changes in patients at different time points after the acute ischemic stroke (AIS). 82 patients with AIS were involved in our study and were tested: within 24 h from the onset of the attack (group A); at 7-day follow-up (group B); and at 3-month follow-up (group C). 81 gender and age matched volunteers were used as controls. Stroke patients in group A had significantly higher concentrations of plasma lipid peroxides and urine 8-isoprostanes when compared with controls. Protein carbonyls were not significantly different in any experimental group compared to controls. Antioxidant capacity of plasma was increased only in experimental group C. Activities of superoxide dismutase and catalase were elevated in all three experimental AIS groups compared to controls. Paraoxonase activity was reduced in groups A and B and unchanged in group C when compared to controls. Glutathione peroxide activity was elevated only in group A. Our results suggest that free radical damage is the highest within 24 h after the attack. During the next 3 months oxidative damage to lipids caused by free radicals is reduced due to activated antioxidant system.

Diabetes-induced abnormalities of mitochondrial function in rat brain cortex: the effect of n-3 fatty acid diet

Diabetic encephalopathy, a proven complication of diabetes is associated with gradually developing end-organ damage in the CNS increasing the risk of stroke, cognitive dysfunction or Alzheimer’s disease. This study investigated the response of rat cortical mitochondria to streptozotocin-induced diabetes and the potential for fish oil emulsion (FOE) to modulate mitochondrial function. Diabetes-induced deregulation of the respiratory chain function as a result of diminished complex I activity (CI) and cytochrome c oxidase hyperactivity was associated with attenuation of antioxidant defense of isolated cortical mitochondria, monitored by SOD activity, the thiol content, the dityrosine and protein–lipid peroxidation adduct formation. A parallel reduction in phosphorylation of the energy marker AMPK has pointed out to disrupted energy homeostasis. Dietary FOE administration partially preserved CI activity, restored AMPK phosphorylation, but was unable to attenuate oxidative stress and prevent the shift toward saturated fatty acids in the cardiolipin composition. Moreover, diabetes has induced alterations in the protein expression of the regulatory COX4 subunit of cytochrome c oxidase, in the inhibitory factor IF1 and ATP5A subunit of F0F1-ATP synthase, in the uncoupling protein UCP4 and supramolecular organization of the respiratory complexes. FOE administration to diabetic rats has partially reversed these alterations. This study suggests diabetes-induced dysfunction of brain cortical mitochondria and its modulation by FOE administration. The intricate diabetic milieu and the n-3 FA nutrigenomic strength, however require further investigations to be able to unequivocally evaluate neuroprotective and adverse effects of FOE supplementation on the diabetic brain function.

Obesity and brain- Is obesity an inflammatory disease of the central nervous system

T growing problem of childhood obesity brings with it a less well-known problem that can have serious ramifications for overweight children. To assess this problem a study was conducted to evaluate healthy school children of Aligarh city to examine the association between obesity and high blood pressure (BP) in school children. 701 school going children between 12 and 16 years of age group of both sexes were selected among all the 4500 children from selected four government and private schools by stratified random sampling. The weight (kg) was taken by a standardized weighing machine while height was measured using a calibrated bar. For diagnosing obesity, the body mass index (BMI) was calculated. Blood pressure (BP) measurements were taken by a mercury sphygmomanometer. Hypertension was defined as systolic and/or diastolic blood pressure over the 95th percentile. The distribution of blood pressure by anthropometric characteristic was examined. Mean, standard deviation, correlation coefficient was used for statistical analysis. The prevalence of high blood pressure was 9.4%. Out of 363 boys, 34 (9.36%) and out 338 girls 32 (9.46%) had high blood pressure. Risks of being overweight and excess weight were identified, respectively, in 6.41% and 2.13% of the children. High blood pressure was significantly more frequent among overweight children (26.66%) and among obese children (60%). The correlation between obesity and hypertension was statistically significant (p<0.01). It is concluded that obesity in childhood has a significant association with hypertension. Both together may be risk factor in childhood can have enormous potential pay-off. Anisa M. Durrani, J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010T current upswing in research interest in lipid droplets (LDs) has been fueled by the connection between LDs and human metabolic disorders, neutral lipid storage in food production and the development of biofuels. However, the mechanisms behind the formation, dynamics and functions of this organelle remain elusive. C. elegans is an excellent animal model for studying LDs, not only due to the ease of genetic manipulation and visualization but also because of the linkage between fat storage, metabolism, reproduction and the lifespan of the animal. However, a lack of knowledge of LD structure-like proteins in C. elegans has limited the utility of the model. Here we identify three LD structure-like proteins, DHS-3, MDT-28, and F22F7.1, which are analogous to mammalian perilipin and adipose differentiation-related protein. A series of comprehensive proteomic studies reveal that the localizations of these proteins are restricted to LDs and that they are among the most abundant on the organelle. We further determined LD targeting sequences and tissue distribution of DHS-3 and MDT-28. Most importantly, we demonstrate that depletion of these proteins alters LD size and affects the lifespan of the animal in a daf-16 independent manner, linking LD structure-like proteins to lifespan for the first time. These findings provide new knowledge and tools for the study of LD biology and will help to establish C. elegans as a powerful model of lipid storage-related disease states. Pingsheng Liu, J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010T central nervous system, dominantly hypothalamus, plays important role in controlling energy homeostasis of the organism. Recent studies reported inflammatory links between obesity and many other disorders. Hypothalamic inflammatory pathways activation is suspected to be initial impulse to trigger metabolic dysfunction of an organism. How inflammatory signals in some cases generate negative energy balance, while in other cases generate positive energy balance and weight gain is not fully known. Is it high-fat diet and lipid infusions which are responsible for activation of hypothalamic inflammation, or is there a primary failure of innate immunity resulting in hypothalamic inflammatory processes? Adipokines levels reflect intesity of brain inflammatory processes. In our presentation, we will offer new insights into this problem. Ema Kantorova et al., J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010Maternal obesity has been associated with obstetrical – in the three trimesters of pregnancy – and neonatal complications. Miscarriage rates and unexplained stillbirth are higher among obese women who have conceived naturally or through Assisted Reproduction Techniques. Obesity increases the risk of pregnancy-induced hypertension and preeclampsia, pre-gestational diabetes and gestational diabetes mellitus, childhood obesity and type 2 diabetes mellitus. Maternal obesity makes preterm labor, operative vaginal delivery and cesarean section more likely in both primigravid and multigravid women, and negatively affects the outcome of vaginal birth after cesarean. The rate of cervical dilation in both nulliparous and multiparous women declines as maternal BMI rises, which shows that obese women are at a higher risk of experiencing dysfunctional labor. Moreover, obese pregnant women are also more likely to present intraoperative and postoperative complications (including postpartum hemorrhage), anesthetic complications (failed intubation at the time of general endotracheal anesthesia), postoperative wound infection and dehiscence, thromboembolism and endomyometritis in the puerperium. Obesity is associated with 18% of obstetric causes of maternal mortality and 80% of anesthesia-related deaths.Background: Scientific literature indicates that body weight is highly influenced not only by genetics and medical conditions, but also by social, cultural and environmental barriers. Health care providers often do not take barriers into account and are frequently unaware that barriers exist. We conducted a photovoice project among ambulatory obese individuals to describe to medical students the struggles and barriers they face due to their weight. Methods: Photovoice participants were recruited via health care providers. Participants attended a 3 hour session focused on describing the photovoice technique. Participants were instructed to use disposable cameras to take 10 photos. The study team reviewed the photographs and discussed them with the participants; participants were then videotaped describing barriers they photographed. The video was shown during family medicine clerkship to 3rd year medical students who were asked questions after viewing the video including, “How did this impact you”, and “What effect did this have on you?” Qualitative responses were evaluated by the study team. Results: Eleven participants with BMI of >30 were recruited and videotaped. 4 of 11 participants reported losing weight after their photovoice experience. Ninety-four medical students viewed the video; responses to questions varied from, “I found myself getting frustrated listening to their stories” to “It made me realize the psychological aspects that go into being overweight”. Conclusion: Photovoice allowed obese patients to describe weight-related barriers and resulted in behavior changes in some participants. The mixed responses to the video illustrate the need for additional intervention to ensure obese patients are treated empathetically. Mara Z. Vitolins et al., J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010T prevalence of Metabolic Syndrome (MS) in Mexico has increased in the last 10 years. MS is a serious health problem due to its related cardiovascular disorders, such as hypertension and heart failure. The latter is among the major causes of death in Mexico; however, the molecular mechanisms responsible for cardiac dysfunction in MS patients are unclear and could be related to anomalies in the cardiac excitation-contraction coupling (E-C coupling). The cardiac Ryanodine Receptor (RyR2) is a macromolecular complex that participates in releasing Ca2+ from internal stores and is involved in E-C coupling. Our aim has been to examine alterations at the expression level, phosphorylation status, Ca2+ sensitivity and in situ function (Ca2+ sparks and Ca2+ transients) of RyR2 that could explain the cardiac dysfunction associated with MS. In an experimental model of MS we found that cardiomyocytes displayed diminished intracellular Ca2+ transients with impaired cell contractility and decrease in Ca2+ spark frequency. [3H] Ryanodine binding showed that functional RyR2 are decreased in MS hearts with no changes of its Ca2+ sensitivity. However MS did not alter the phosphorylation of RyR2 at serine-2809 linked to the development of heart failure due to leaky RyR2. Then, the impaired RyR2 functionality could be attributable to additional stress-induced RyR2 modifications but not to changes at RyR2 phosphorylation status. RyR2 alterations may account for the poor overall cardiac outcome found in MS patients and could be targeting for future therapies. Angelica Rueda, J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010King Saud University, Saudi Arabia Abstract: The world is witnessing a diabetes pandemic. It is expected that the estimated number of patients with diabetes of 150 million in the late 1990s will reach 300 million by 2025. In the late 1970s and early 1980s diabetes was not considered a commonly encountered medical diagnosis in Saudi Arabia even in high-risk groups, and among the male Saudi population the prevalence of diabetes was not different from other parts of the world. However, this seems to have changed dramatically in the last two decades, as the prevalence of diabetes in Saudi Arabia is now one of the highest in the world. Diabetes mellitus, especially type 2 is a polygenic disorder and the high consanguinity rate among Saudis may be playing a significant role in its prevalence. Also, obesity is a wellknown and strong risk factor for diabetes, especially in high-risk population. National epidemiological survey by AlNozha et al (2004) showed the overall prevalence of type 2 diabetes mellitus is 27.3%. Insulin resistance is an important feature of type 2 diabetes. It is being increasingly recognized that low testosterone levels in men are associated with reduced insulin sensitivity and type 2 diabetes. Furthermore, male hypogonadism is a clinical condition that affects a significant number of men in the United States and can involve up to 50% of men diagnosed with type 2 diabetes. Older age and obesity may be risk factors, as both are associated with type 2 diabetes and both decrease testosterone levels. Sex hormone-binding globulin (SHBG), the major serum carrier protein for testosterone, also may have an impact. SHBG levels fall with obesity and increase with aging. Some studies indicate lower SHBG levels in type 2 diabetes. However, free testosterone levels fall with increasing age and obesity, rendering many type 2 diabetic patients testosterone deficient. Recent work shows a high prevalence of low testosterone and inappropriately low LH and FSH concentrations in type 2 diabetes. This syndrome of hypogonadotrophic hypogonadism is associated with obesity, and other features of the metabolic syndrome (obesity and overweight, hypertension and hyperlipidemia) in patients with type 2 diabetes.However, the duration of diabetes or HbA1c were not related to hypogonadotrophic hypogonadism. Furthermore, recent data show that hypogonadotrophic hypogonadism is also observed frequently in patients with the metabolic syndrome without diabetes but is not associated with type 1 diabetes. Thus, hypogonadotrophic hypogonadism appears to be related to the two major conditions associated with insulin resistance: type 2 diabetes and the metabolic syndrome. CRP concentrations have been shown to be elevated in patients with hypogonadotrophic hypogonadism and are inversely related to plasma testosterone concentrations. This is of interest since inflammatory mechanisms may have a cardinal role in the pathogenesis of insulin resistance. Hypogonadotrophic hypogonadism may be the result of insulin resistance at the level of the GnRH secreting neuron. Low testosterone concentrations in type 2 diabetic men have also been related to a significantly lower hematocrit and thus to an increased frequency of mild anemia. Low testosterone concentrations are also related to an increase in total and regional adiposity, and to lower bone density. Erectile dysfunction (ED) is a common and distressing complication of diabetes. Large differences in the reported prevalence of ED from 35% to 90% among diabetic men could be due to differences in methodology and population characteristics. Advancing age, duration of diabetes, poor glycaemic control, hypertension, hyperlipidemia, sedentary lifestyle, smoking, and presence of other diabetic complications have been shown to be associated with ED in diabetic patients in cross-sectional studies. ED in diabetic patients is multifactorial in aetiology and is more severe and more resistant to treatment compared with non-diabetics. There are no studies demonstrating the prevalence of hypogonadism in type 2 diabetic patients in Saudi Arabia .The aims of this study were to find out the prevalence of hypogonadism in Saudi type 2 diabetic patients by measuring total & bioavailable testosterone levels and by calculating the free testosterone levels. Moreover, the study also aimed to identify the effect of metabolic syndrome and other factors on testosterone levels and thus to highlight the importance of evaluating the gonadal system of type 2 diabetic patient visiting the clinic. CONCLUSIONS— Testosterone levels are frequently low in Saudi men with type 2 diabetes, and the majority of these men have symptoms of hypogonadism. Obesity is associated with low testosterone levels in diabetic men.The prevalence of obesity and cardiovascular diseases (CVDs) is on the rise in developing countries as people tend to adopt more urban lifestyles. Recent reports however indicate that waist and hip circumferences (WC and HC) may be better indicators of CVD risk. The aim of the current study was to evaluate the relationship between BMI, WC and HC on blood pressure, lipid profiles and some markers of CVD risk in female adolescents in Mthatha. 76 female high school learners, 13-17 years old were recruited into this study: 38 were lean (BMI≤75 th percentile) and 38 overweight/obese (O/O) (BMI≥85 th percentile). Anthropometric and blood pressure measurements were performed for all participants, after which fasting blood samples were collected for biochemistry. Lean learners had higher triglyceride and HDL-C while O/O learners had significantly lower HDL-C and higher total cholesterol. Mean systolic blood pressure (MSBP) but not mean diastolic blood pressure (MDBP) was significantly higher in the O/O group. Higher WC and HC were independently associated with significantly higher MSBP and MDBP. Serum hs-CRP but not adiponectin levels were significantly higher in O/O group compared to the lean though adiponectin correlated negatively with WC and HC. Increased HC and not only BMI and WC are risk factors for increased blood pressure in female adolescents living in Mthatha.R transplantation (RT) is a standard treatment for end-stage renal disease, standing at more than 90% survival rate after one yr, and at over a 70% survival rate after five yr. The majority of transplanted patients enjoy an excellent quality of life but complications can occur in the long term, and can develop subclinically in otherwise well subjects; there are various underestimated nutritional and metabolic aspects, including the so-called post-transplant overweight and obesity. During the post-transplant period, the use of immunosuppressants, corticosteroids, calcineurin inhibitors, and the presence of risk factors, including non-alcoholic fatty liver disease and kidney and bone complications have been largely implicated in development of obesity. Strategies to reduce the progression to obesity and increased body mass index are mandatory. Follow up of RT patients should include careful screening for diabetes, and dyslipidemia and to support weight reduction with a carefully constructed program, particularly based on diet modification and exercise. With early identification and appropriate and aggressive management, excellent long-term health outcomes and acceptable survival can be achieved. Amin R. Soliman, J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010Fructose consumption is implicated as one of the dietary causes of non-alcoholic fatty liver disease (NAFLD). Obesity is not one of the requirements for developing NAFLD. Chinese (C) patients that were referred to us for dietary counseling had a BMI that was much lower than that of the Non-Chinese (NC) population. The rate of both liver cirrhosis and liver cancer, of which NAFLD is a major risk factor, is on the rise in the Ontario C population. What is in the diet of the C group that causes them to develop NAFLD, even when they are not obese?A key feature of most weight management programs is to focus on whether you feel hungry or full. A lifetime of yo yo dieting makes such messages so confusing that one questions if it is really possible to distinguish the difference. Often the outcome is binge eating behavior, which itself is not well defined. The restraint theory literature has unveiled how cognitive processes trigger binge eating behavior. Brain imaging techniques have added credence to the restraint theory as well as supported clues to the predisposition of binge eating. Understanding the neurophysiology that triggers eating may provide some answers and assists the compulsive eater. Gastric bypass outcome data suggest the need to address more aggressively BED behavior. The incites from the restraint theory, brain imaging and gastric bypass provide clues on what therapeutic interventions will be most successful in treatment and long term recovery. Description: Binge eating disorder is included as a diagnosis in the new DSM V and yet there is still a great deal of controversy surrounding the diagnostic criteria and etiology. This talk through investigating brain imaging, restraint theory, the addiction model and attachment theory may provide clarity to better address the confusion and provide a foundation for effective treatment. Objectives: At the conclusion of this presentation participants will be able to: 1. Identify the pathways, neurotransmitters and receptors responsible for binge eating behavior. 2. Explain the etiology of binge behavior and its link with body dissatisfaction and depression. 3. Recognize the variety of binge behaviors and the continuum of clinical severity. Ralph Carson, J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010Background: Obesity is a silent killer and a forerunner of many complications if persists long. Various studies with animal model have identified the role of leptin, the hormone of adipose tissue; in obesity and its associated complications like diabetes and atherosclerosis inlater stages. The exact mechanism to know how leptin influences insulin action in body and thereby leading to diabetes or post diabetic atherosclerosis is still not completely evaluated. Hypercholesterolemia was only found common to all these three states. The present study, therefore, evaluated the role of obesity on the expression of LDLR receptor, INSULIN receptor and LEPTIN receptor. Method: Receptor expression was done by immunohistochemistry/western blot. The serum level of lipids was measured by enzyme based kit method. The serum level of insulin and leptin and its soluble receptor were measured by ELISA based kit. Results: The blot for insulin expression shows no chamge with body weight; the blot for leptin receptor shows decrease expression with weight gain and blot for LDLR shows decrease expression with weight gain. The serum levels of insulin and leptin are increased with weight gain but soluble receptor for leptin did not change significantly. Even the obese group showed decrease tyrosine phosphorylation of insulin receptor. Conclusion: This study has given some possible reasons of the inter-association of hyperleptinemia, hypercholesterolemia and hyperinsulinemia by showing possibilities of inactivation of insulin and LDLR receptor with leptin resistance. Puja Beriwal, J Obes Weight Loss Ther 2013, 3:7 http://dx.doi.org/10.4172/2165-7904.S1.010Diabetes, obesity and metabolic syndrome are in essence metabolic disorders. A whole gamut of research data indicate that they are complexly entangled and bear a close inter-relationship. These disorders are life-style diseases as well, having genesis in modifiable modern dietary habits and technology-driven sedentary living patterns, apart from non-modifiable genetic makeup. They have an important impact on the morbidity and mortality patterns directly and through their effects on individual aging process. The aging population has a higher incidence of diabetes. On the other hand, overweight and obese persons have higher incidence of diabetes. The research has proven that obesity accelerates aging of adipose tissue, which in turn leads to activation of cascade of various metabolic pathways responsible for aging. Diabetes, too, appears to accelerate aging at cellular level through metabolic alterations. The experiments in normal mice, variously knocked-out-mice and Agouti mice have unfolded the understanding of genetic basis and metabolic pathways. In experiments the Agouti mice, which are genetically obese, having high levels of reactive oxygen species (ROS), increased DNA damage and higher expression of inflammatory markers, lacking telomerase develop shorter telomeres during successive generations. These changes are comparable to normal aging mice. Thus, inference from the research indicates that obesity increases the formation of ROS in adipose cells, and shortens telomeres, which in turn, activates the p53 tumor suppressor leading to inflammation manifested by infiltration by macrophages and elevated level of cytokines. This has been shown to lead to insulin resistance, impaired glucose tolerance and diabetes. Similarly, the histological and physiological changes in aging organs are associated with oxidative stress, genetic instability and disruption of homeostatic pathways. Aging has been linked to telomere shortening due to impaired cellular ability to detoxify ROS, leading to p53 activation. This potentially impairs insulin secretion and sensitivity. There are, thus, similarities in metabolic dysfunction and deregulation in obese states, diabetes and aging. It has been highlighted that diabetes, obesity and aging may share similar mechanisms and metabolic pathways at cellular level. Whether diabetes-mediated or obesity-mediated aging is reversible? The caloric restriction with adequate nutrition (CRAN) reduces aging in normal population and has a favorable impact on glucose homeostasis. The CRAN, a selective CRAN or a modality having favorable impact on homeostasis, can be an answer for the exacerbated aging in the special conditions like diabetes, obesity and metabolic syndrome.