Altered Mitochondrial Function and Oxidative Stress in Leukocytes of Anorexia Nervosa Patients

Context

Anorexia nervosa is a common illness among adolescents and is characterised by oxidative stress.

Objective

The effects of anorexia on mitochondrial function and redox state in leukocytes from anorexic subjects were evaluated.

Design and setting

A multi-centre, cross-sectional case-control study was performed.

Patients

Our study population consisted of 20 anorexic patients and 20 age-matched controls, all of which were Caucasian women.

Main outcome measures

Anthropometric and metabolic parameters were evaluated in the study population. To assess whether anorexia nervosa affects mitochondrial function and redox state in leukocytes of anorexic patients, we measured mitochondrial oxygen consumption, membrane potential, reactive oxygen species production, glutathione levels, mitochondrial mass, and complex I and III activity in polymorphonuclear cells.

Results

Mitochondrial function was impaired in the leukocytes of the anorexic patients. This was evident in a decrease in mitochondrial O₂ consumption (P<0.05), mitochondrial membrane potential (P<0.01) and GSH levels (P<0.05), and an increase in ROS production (P<0.05) with respect to control subjects. Furthermore, a reduction of mitochondrial mass was detected in leukocytes of the anorexic patients (P<0.05), while the activity of mitochondrial complex I (P<0.001), but not that of complex III, was found to be inhibited in the same population.

Conclusions

Oxidative stress is produced in the leukocytes of anorexic patients and is closely related to mitochondrial dysfunction. Our results lead us to propose that the oxidative stress that occurs in anorexia takes place at mitochondrial complex I. Future research concerning mitochondrial dysfunction and oxidative stress should aim to determine the physiological mechanism involved in this effect and the physiological impact of anorexia.     

The Homeostatic Chemokine CCL21 Predicts Mortality in Aortic Stenosis Patients and Modulates Left Ventricular Remodeling

Background

CCL21 acting through CCR7, is termed a homeostatic chemokine. Based on its role in concerting immunological responses and its proposed involvement in tissue remodeling, we hypothesized that this chemokine could play a role in myocardial remodeling during left ventricular (LV) pressure overload.

Methods and Results

Our main findings were: (i) Serum levels of CCL21 were markedly raised in patients with symptomatic aortic stenosis (AS, n = 136) as compared with healthy controls (n = 20). (ii) A CCL21 level in the highest tertile was independently associated with all-cause mortality in these patients. (iii) Immunostaining suggested the presence of CCR7 on macrophages, endothelial cells and fibroblasts within calcified human aortic valves. (iv). Mice exposed to LV pressure overload showed enhanced myocardial expression of CCL21 and CCR7 mRNA, and increased CCL21 protein levels. (v) CCR7^−/− mice subjected to three weeks of LV pressure overload had similar heart weights compared to wild type mice, but increased LV dilatation and reduced wall thickness.

Conclusions

Our studies, combining experiments in clinical and experimental LV pressure overload, suggest that CCL21/CCR7 interactions might be involved in the response to pressure overload secondary to AS.     

Influence of Aerobic Training on the Reduced Vasoconstriction to Angiotensin II in Rats Exposed to Intrauterine Growth Restriction: Possible Role of Oxidative Stress and AT2 Receptor of Angiotensin II

Intrauterine growth restriction (IUGR) is associated with impaired vascular function, which contributes to the increased incidence of chronic disease. The aim of this study was to investigate whether aerobic training improves AngII-induced vasoconstriction in IUGR rats. Moreover, we assess the role of superoxide dismutase (SOD) isoforms and NADPH oxidase-derived superoxide anions in this improvement. Female Wistar rats were randomly divided into two groups on day 1 of pregnancy. A control group was fed standard chow ad libitum, and a restricted group was fed 50% of the ad libitum intake throughout gestation. At 8 weeks of age, male offspring from both groups were randomly assigned to 4 experimental groups: sedentary control (SC), trained control (TC), sedentary restricted (SRT), and trained restricted (TRT). The training protocol was performed on a treadmill and consisted of a continuous 60-min session 5 days/week for 10 weeks. Following aerobic training, concentration–response curves to AngII were obtained in endothelium-intact aortic rings. Protein expression of SOD isoforms, AngII receptors and the NADPH oxidase component p47^phox was assessed by Western blot analysis. The dihydroethidium was used to evaluate the in situ superoxide levels under basal conditions or in the presence of apocynin, losartan or PD 123,319. Our results indicate that aerobic training can prevent IUGR-associated increases in AngII-dependent vasoconstriction and can restore basal superoxide levels in the aortic rings of TRT rats. Moreover, we observed that aerobic training normalized the increased p47^phox protein expression and increased MnSOD and AT₂ receptor protein expression in thoracic aortas of SRT rats. In summary, aerobic training can result in an upregulation of antioxidant defense by improved of MnSOD expression and attenuation of NADPH oxidase component p47^phox. These effects are accompanied by increased expression of AT₂ receptor, which provide positive effects against Ang II–induced superoxide generation, resulting in attenuation of AngII-induced vasoconstriction.     

Renal Function in Hepatosplenic Schistosomiasis – An Assessment of Renal Tubular Disorders

Background

Renal involvement in Schistosoma mansoni infection is not well studied. The aim of this study is to investigate the occurrence of renal abnormalities in patients with hepatosplenic schistosomiasis (HSS), especially renal tubular disorders.

Methods

This is a cross-sectional study with 20 consecutive patients with HSS followed in a medical center in Maceió, Alagoas, Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl₂) after a 12-h period of water and food deprivation. The biomarker monocyte chemoattractant protein 1 (MCP-1) was quantified in urine. Fractional excretion of sodium (FE_Na+), transtubular potassium gradient (TTKG) and solute-free water reabsorption (TcH₂O) were calculated. The HSS group was compared to a group of 17 healthy volunteers.

Results

Patients'' mean age and gender were similar to controls. Urinary acidification deficit was found in 45% of HSS patients. Urinary osmolality was significantly lower in HSS patients (588±112 vs. 764±165 mOsm/kg, p = 0,001) after a 12-h period of water deprivation. TcH₂O was lower in HSS patients (0.72±0.5 vs. 1.1±0.3, p = 0.04). Urinary concentration deficit was found in 85% of HSS patients. The values of MCP-1 were higher in HSS group than in control group (122±134 vs. 40±28 pg/mg-Cr, p = 0.01) and positively correlated with the values of microalbuminuria and proteinuria.

Conclusions

HSS is associated with important kidney dysfunction. The main abnormalities found were urinary concentrating ability and incomplete distal acidification defect, demonstrating the occurrence of tubular dysfunction. There was also an increase in urinary MCP-1, which appears to be a more sensitive marker of renal damage than urinary albumin excretion rate.     

Real-Time PCR Quantification of the Plant Growth Promoting Bacteria Herbaspirillum seropedicae Strain SmR1 in Maize Roots

The plant growth promoting bacteria Herbaspirillum seropedicae SmR1 is an endophytic diazotroph found in several economically important crops. Considering that methods to monitor the plant–bacteria interaction are required, our objective was to develop a real-time PCR method for quantification of PGPB H. seropedicae in the rhizosphere of maize seedlings. Primer pairs were designed, and their specificity was verified using DNA from 12 different bacterial species. Ten standard curves of qPCR assay using HERBAS1 primers and tenfold serial dilutions of H. seropedicae SmR1 DNA were performed, and PCR efficiency of 91 % and correlation coefficient of 0.99 were obtained. H. seropedicae SmR1 limit of detection was 10¹ copies (corresponding to 60.3 fg of bacterial DNA). qPCR assay using HERBAS1 was used to detect and quantify H. seropedicae strain SmR1 in inoculated maize roots, cultivated in vitro and in pots, harvested 1, 4, 7, and 10 days after inoculation. The estimated bacterial DNA copy number per gram of root was in the range 10⁷–10⁹ for plants grown in vitro and it was around 10⁶ for plants grown in pots. Primer pair HERBAS1 was able to quantify H. seropedicae SmR1, and this assay can be useful for monitoring plant–bacteria interaction.     

Effects of Ezetimibe on Endothelial Progenitor Cells and Microparticles in High-Risk Patients

Imbalance on endothelial turnover can predict cardiovascular outcomes. We aimed at evaluating the effects of lipid-modifying therapies on circulating endothelial progenitor cells (EPCs), endothelial microparticles (EMPs), and platelet microparticles (PMPs) in high cardiovascular risk subjects with elevated C-reactive protein (CRP). Sixty-three individuals with coronary heart disease (CHD) or CHD risk equivalent on stable statin therapy, with LDL-cholesterol <100 mg/dL and CRP ≥2.0 mg/L were selected. After a 4-week run-in period with atorvastatin 10 mg, those with persistent CRP ≥2.0 mg/L were randomized to another 4-week treatment period with atorvastatin 40 mg, ezetimibe 10 mg or atorvastatin 40 mg/ezetimibe 10 mg. EPC (CD34⁺/CD133⁺/KDR⁺), EMP (CD51⁺), and PMP (CD42⁺/CD31⁺) were quantified by flow cytometry. Atorvastatin 40 mg and atorvastatin 40 mg/ezetimibe 10 mg reduced LDL-cholesterol (P < 0.001, paired T test, vs. baseline). Combined therapy, but not ezetimibe reduced CRP. CD34⁺/KDR⁺ EPC were reduced after ezetimibe alone (P = 0.011 vs. baseline, Wilcoxon test) or combined with atorvastatin (P = 0.016 vs. baseline, Wilcoxon test). In addition, ezetimibe increased CD51⁺ EMP (P = 0.017 vs. baseline, Wilcoxon test). No correlations between these markers and LDL-cholesterol or CRP were observed. These results contribute to understand the link between inflammation and vascular homeostasis and highlight the broader benefit of statins decreasing inflammation and preventing microparticles release, an effect not observed with ezetimibe alone.     

Saponin as regulator of biofuel: implication for ethnobotanical management of diabetes

There has been a sharp rise in the global prevalence of diabetes, obesity, and their comorbid conditions within the last decade prompting significant research into possible causes and cure via therapeutic intervention and lifestyle adjustments. Here, the molecular bases of antidiabetic plants used in the prehistorical treatment of diabetes and obesity are reviewed with particular focus on saponin as the phytotherapeutic principle. Until recently, the phytotherapeutic potentials of saponins have been masked in the heterogeneity of phytochemicals co-extractable during traditional preparations. With improved technique of purification and cutting edge biological assay methods, saponins have emerged as a regulator of primary biofuel availability through direct interaction with energy metabolism, cell signaling, and gene expression. Specific cases of lipoprotein lipase/peroxisome proliferator-activated receptor (PPAR)-gamma/phosphatidylinositide 3-kinase (PI-3-K)/protein kinase B (Akt) activation, adiponectin gene upregulation, fatty acid binding protein 4 repression (FABP4), and glucose transporter type 4 (Glut4) membrane exocytosis have been documented which provide molecular basis for hypocholesterolemic, hypoglycemic, and anti-obesity manifestations observed in experimental animals following saponin treatment. Although intensified research is required to characterize the pharmacophoric features in saponins exhibiting these interactions, however, this preliminary lead is valuable if the world will be free of diabetes, obesity, hypertension, hyperlipidemia, and atherosclerosis in no distant future.     

Contrasting long‐term records of biomass burning in wet and dry savannas of equatorial East Africa

Rainfall controls fire in tropical savanna ecosystems through impacting both the amount and flammability of plant biomass, and consequently, predicted changes in tropical precipitation over the next century are likely to have contrasting effects on the fire regimes of wet and dry savannas. We reconstructed the long‐term dynamics of biomass burning in equatorial East Africa, using fossil charcoal particles from two well‐dated lake‐sediment records in western Uganda and central Kenya. We compared these high‐resolution (5 years/sample) time series of biomass burning, spanning the last 3800 and 1200 years, with independent data on past hydroclimatic variability and vegetation dynamics. In western Uganda, a rapid (<100 years) and permanent increase in burning occurred around 2170 years ago, when climatic drying replaced semideciduous forest by wooded grassland. At the century time scale, biomass burning was inversely related to moisture balance for much of the next two millennia until ca. 1750 ad , when burning increased strongly despite regional climate becoming wetter. A sustained decrease in burning since the mid20th century reflects the intensified modern‐day landscape conversion into cropland and plantations. In contrast, in semiarid central Kenya, biomass burning peaked at intermediate moisture‐balance levels, whereas it was lower both during the wettest and driest multidecadal periods of the last 1200 years. Here, burning steadily increased since the mid20th century, presumably due to more frequent deliberate ignitions for bush clearing and cattle ranching. Both the observed historical trends and regional contrasts in biomass burning are consistent with spatial variability in fire regimes across the African savanna biome today. They demonstrate the strong dependence of East African fire regimes on both climatic moisture balance and vegetation, and the extent to which this dependence is now being overridden by anthropogenic activity.