Dietary restriction (DR) as a means to increase longevity is well-established in a number of model organisms from yeast to primates. DR also improves metabolic fitness and increases resistance to acute oxidative, carcinogenic and toxicological stressors - benefits with more immediate potential for clinical translation than increased lifespan. While the detailed mechanism of DR action remains unclear, a conceptual framework involving an adaptive, or hormetic response to the stress of nutrient/energy deprivation has been proposed. A key prediction of the hormesis hypothesis of DR is that beneficial adaptations occur in response to an increase in reactive oxygen/nitrogen species (ROS). These ROS may be derived either from increased mitochondrial respiration or increased xenobiotic metabolism in the case of some DR mimetics. This review will focus on the potential role of the redox-sensing transcription factor NF-E2-related factor 2 (NRF2) and its control of the evolutionarily conserved antioxidant/redox cycling and detoxification systems, collectively known as the Phase II response, in the adaptive response to DR.
MRI using hyperpolarized 13C-labeled pyruvate is a promising tool to biochemically profile tumors and monitor their response to therapy. This technique requires injection of pyruvate into tumor-bearing animals. Pyruvate is an endogenous entity but the influence of exogenously injected bolus doses of pyruvate on tumor microenvironment is not well understood. In this study, the effect of injecting a bolus of pyruvate on tumor oxygen status was investigated. EPR oxygen imaging revealed that the partial pressure of oxygen (pO2) in squamous cell carcinoma (SCC) implanted in mice decreased significantly 30 min after [1-13C]pyruvate injection, but recovered to pre-injection levels after 5 hours. DCE-MRI studies showed that, at the dose of pyruvate used, no changes in tumor perfusion were noticed. Immunohistochemical analysis of hypoxic marker pimonidazole independently verified that the SCC tumor transiently became more hypoxic by pyruvate injection. Efficacy of radiotherapy was suppressed when X-irradiation was delivered during the period of pyruvate-induced transient hypoxia. These results suggest importance of taking into account the transient decrease in tumor pO2 after pyruvate injection in hyperpolarized 13C MRI, since tumor oxygen status is an important factor in determining outcomes of therapies.
electron paramagnetic resonance imaging; hyperpolarized 13C MRI; tumor hypoxia; radiotherapy
This exploratory study assessed whether maternal recall of childhood feeding and eating practices differed across anorexia nervosa (AN) subtypes. Participants were 325 women from the Genetics of Anorexia Nervosa study whose mothers completed a childhood feeding and eating questionnaire. Multinomial logistic regression analyses were used to predict AN subtype from measures related to childhood eating: (a) infant feeding (breastfed, feeding schedule, age of solid food introduction), (b) childhood picky eating (picky eating before age one and between ages one and five), and (c) infant gastrointestinal problems (vomiting and colic). Results revealed no significant differences in retrospective maternal report of childhood feeding and eating practices among AN subtypes.
Anorexia Nervosa; Anorexia Nervosa Subtype; Feeding; Maternal Report; Infancy
To examine the caloric intake in women with anorexia nervosa (AN) and how it varies by day as a function of the presence or absence of binge eating and/or purging behaviors.
Female participants with AN (n = 84, mean age = 24.4, range 18–51) were recruited from three different sites. Data on food intake were obtained through the use of 24-h dietary recall using the Nutritional Data Systems for Research, and data on binge eating and purging behaviors were collected on palmtop computers using an ecological momentary assessment paradigm. Daily macronutrient intake was compared on days during which binge eating and/or purging behaviors did or did not occur.
On days during which binge eating and purging behaviors both occurred, participants reported significantly greater kilocalorie intake when compared with days when neither behavior occurred, or when only binge eating or purging occurred. Binge eating episodes were only modest in size on days when purging did not occur. Energy intake overall was higher than expected.
Intake on days where binge eating occurred varied dramatically based on whether or not purging occurred. Whether markedly increased binge eating intake was causally related to purging is unclear. Nonetheless eating episodes were at times quite large and equivalent to those reported by participants with bulimia nervosa in other research.
AN; binge eating; compensatory behaviors; caloric intake
Dietary restriction, or reduced food intake without malnutrition, increases life span, health span, and acute stress resistance in model organisms from yeast to nonhuman primates. Although dietary restriction is beneficial for human health, this treatment is not widely used in the clinic. Here, we show that short-term, ad libitum feeding of diets lacking essential nutrients increased resistance to surgical stress in a mouse model of ischemia reperfusion injury. Dietary preconditioning by 6 to 14 days of total protein deprivation, or removal of the single essential amino acid tryptophan, protected against renal and hepatic ischemic injury, resulting in reduced inflammation and preserved organ function. Pharmacological treatment with halofuginone, which activated the amino acid starvation response within 3 days by mimicking proline deprivation, was also beneficial. Both dietary and pharmacological interventions required the amino acid sensor and eIF2α (eukaryotic translation initiation factor 2α) kinase Gcn2 (general control nonderepressible 2), implicating the amino acid starvation response and translational control in stress protection. Thus, short-term dietary or pharmacological interventions that modulate amino acid sensing can confer stress resistance in models of surgical ischemia reperfusion injury.
Oxygen maps derived from electron paramagnetic resonance spectral-spatial imaging (EPRI) are based upon the relaxivity of molecular Oxygen with paramagnetic spin probes. This technique can be combined with MRI to facilitate mapping of pO2 values in specific anatomic locations with high precision. The co-registration procedure, which matches the physical and digital dimensions of EPR and MR images, may present the pO2 map at the higher MRI resolution, exaggerating the spatial resolution of oxygen, making it difficult to precisely distinguish hypoxic regions from normoxic regions. The latter distinction is critical in monitoring the treatment of cancer by radiation and chemotherapy, since it is well-established that hypoxic regions are three or four times more resistant to treatment compared to normoxic regions. The aim of this article is to describe pO2 maps based on the intrinsic resolution of EPRI. A spectral parameter that affects the intrinsic spatial resolution of EPRI is the full width at half maximum (FWHM) height of the gradient-free EPR absorption line in frequency-encoded imaging. In single point imaging too, the transverse relaxation times (T2*) limit the resolution since the signal decays by exp(-tp/T2*) where the delay time after excitation pulse, tp, is related to the resolution. Although the spin densities of two point objects may be resolved at this separation, it is inadequate to evaluate quantitative changes of pO2 levels since the linewidths are proportionately affected by pO2. A spatial separation of at least twice this resolution is necessary to correctly identify a change in pO2 level. In addition, the pO2 values are blurred by uncertainties arising from spectral dimensions. Blurring due to noise and low resolution modulates the pO2 levels at the boundaries of hypoxic and normoxic regions resulting in higher apparent pO2 levels in hypoxic regions. Therefore, specification of intrinsic resolution and pO2 uncertainties are necessary to interpret digitally processed pO2 illustrations.
EPR imaging; intrinsic resolution; digital resolution; deconvolution; oximetry
Daily pre-exposure prophylaxis (PrEP) with Truvada (a combination of emtricitabine (FTC) and tenofovir (TFV) disoproxil fumarate (TDF)) is a novel HIV prevention strategy recently found to prevent HIV transmission in men who have sex with men and heterosexual couples. We previously showed that a coitally-dependent Truvada regimen protected macaques against rectal SHIV transmission. Here we examined FTC and tenofovir TFV exposure in vaginal tissues after oral dosing and assessed if peri-coital Truvada also protects macaques against vaginal SHIV infection.
The pharmacokinetic profile of emtricitabine (FTC) and tenofovir (TFV) was evaluated at first dose. FTC and TFV levels were measured in blood plasma, rectal, and vaginal secretions. Intracellular concentrations of FTC-triphosphate (FTC-TP) and TFV-diphosphate (TFV-DP) were measured in PBMCs, rectal tissues, and vaginal tissues. Efficacy of Truvada in preventing vaginal SHIV infection was assessed using a repeat-exposure vaginal SHIV transmission model consisting of weekly exposures to low doses of SHIV162p3. Six pigtail macaques with normal menstrual cycles received Truvada 24 h before and 2 h after each weekly virus exposure and six received placebo. Infection was monitored by serology and PCR amplification of SHIV RNA and DNA.
As in humans, the concentration of FTC was higher than the concentration of TFV in vaginal secretions. Also as in humans, TFV levels in vaginal secretions were lower than in rectal secretions. Intracellular TFV-DP concentrations were also lower in vaginal tissues than in rectal tissues. Despite the low vaginal TFV exposure, all six treated macaques were protected from infection after 18 exposures or 4 full menstrual cycles. In contrast, all 6 control animals were infected.
We modeled a peri-coital regimen with two doses of Truvada and showed that it fully protected macaques from repeated SHIV exposures. Our results open the possibility for simplified PrEP regimens to prevent vaginal HIV transmission in women.
Rapamycin is an allosteric inhibitor of mammalian target of rapamycin, and inhibits tumor growth and angiogenesis. Recent studies suggested a possibility that rapamycin renormalizes aberrant tumor vasculature and improves tumor oxygenation. The longitudinal effects of rapamycin on angiogenesis and tumor oxygenation were evaluated in murine squamous cell carcinoma (SCCVII) by electron paramagnetic resonance imaging (EPRI) and magnetic resonance imaging (MRI) to identify an optimal time after rapamycin treatment for enhanced tumor radioresponse. Rapamycin treatment was initiated on SCCVII solid tumors 8 days after implantation (500–750 mm3) and measurements of tumor pO2 and blood volume were conducted from day 8 to 14 by EPRI/MRI. Microvessel density was evaluated over the same time period by immunohistochemical analysis. Tumor blood volume as measured by MRI significantly decreased 2 days after rapamycin treatment. Tumor pO2 levels modestly but significantly increased 2 days after rapamycin treatment; whereas, it decreased in non-treated control tumors. Furthermore, the fraction of hypoxic area (pixels with pO2<10 mm Hg) in the tumor region decreased 2 days after rapamycin treatments. Immunohistochemical analysis of tumor microvessel density and pericyte coverage revealed that microvessel density decreased 2 days after rapamycin treatment, but pericyte coverage did not change, similar to what was seen with anti-angiogenic agents such as sunitinib which cause vascular renormalization. Collectively, EPRI/MRI co-imaging can provide non-invasive evidence of rapamycin-induced vascular renormalization and resultant transient increase in tumor oxygenation. Improved oxygenation by rapamycin treatment provides a temporal window for anti-cancer therapies to realize enhanced response to radiotherapy.
To determine the effects of total body irradiation (TBI) dose, fractionation, and lung shielding on hematopoietic stem cell homing to the bone marrow.
Material and Methods
Bone marrow (BM) cells were extracted from tibiae and femurs of B6-GFP mice and were transplanted into B6 mice. Recipient mice had either: 1) no radiation, 2) single dose TBI at 13.6 Gray (Gy), 3) single dose TBI at 13.6 Gy with reduced lung exposure to 0.4 Gy by shielding, 4) split dose TBI at 12 Gy to twice/day over four days, or 5) split dose TBI at 12 Gy to twice/day over four days with reduced lung exposure to 0.36 Gy by shielding. The last radiation exposure preceded tail vein injection by 4–6 hours. Mice were sacrificed after 18 hours.
Homing of GFP positive, lineage negative cells was not significantly improved in any irradiated group compared to control. Homing of GFP positive, lineage negative, Kit positive cells was significantly worse in all irradiated groups.
TBI does not improve the homing of lineage negative donor BM cells to the recipient marrow. Homing of lineage negative, Kit positive donor BM cells was significantly worse following TBI, with or without lung dose reduction.
TBI; Lung Shielding; Dose Reduced; BID; Stem
Excess reactive oxygen species (ROS) generated from ionizing radiation (IR) or endogenous sources like cellular respiration and inflammation produce cytotoxic effects that can lead to carcinogenesis. Resveratrol (RSV), a polyphenol with antioxidant and anticarcinogenic capabilities, has shown promise as a potential radiation modifier. The present study focuses on examining the effects of RSV or RSV metabolites as a radiation modifier in normal tissue. RSV or a RSV metabolite, piceatannol (PIC) did not protect human lung fibroblasts (1522) from the radiation-induced cell killing. Likewise, neither RSV nor PIC afforded protection against lethal total body IR in C3H mice. Additional research has shown protection in cells against hydrogen peroxide when treated with RSV. Therefore, clonogenic survival was measured in 1522 cells with RSV and RSV metabolites. Only the RSV derivative, piceatannol (PIC), showed protection against hydrogen peroxide mediated cytotoxicity; whereas, RSV enhanced hydrogen peroxide sensitivity at a 50 µM concentration; the remaining metabolites evaluated had little to no effect on survival. PIC also showed enhancement to peroxide exposure at a higher concentration (150 µM). A potential mechanism for RSV-induced sensitivity to peroxides could be its ability to block 1522 cells in the S-phase, which is most sensitive to hydrogen peroxide treatment. In addition, both RSV and PIC can be oxidized to phenoxyl radicals and quinones, which may exert cytotoxic effects. These cytotoxic effects were abolished when HBED, a metal chelator, was added. Taken together RSV and many of its metabolic derivatives are not effective as chemical radioprotectors and should not be considered for clinical use.
resveratrol; piceatannol; antioxidants; oxidative stress; peroxide; ionizing radiation; quinones
Fibrosis of normal tissues often accompanies radiation treatment of cancer. Activation of the transforming growth factor-β (TGF-β) signaling pathway is thought to play a major role in radiation-induced fibrosis and has prompted the development and assessment of low molecular weight inhibitors of the pathway. Previous studies with halofuginone have shown it to inhibit TGF-β signaling in vitro and protect mice from radiation-induced leg contraction (a model for soft tissue fibrosis). The current study confirms these findings for HaCaT cells stimulated with exogenous TGF-β treatment. Reducing the halifuginone treatment from 7 days/week (used previously) to 5 days/week post-radiation exposure provided significant protection against radiation-induced leg contraction in mice 3 and 4 months post-radiation treatment. Halofuginone treatment was shown to attenuate TGF-β signaling molecules taken from irradiated skin including TGF-βRII, pSmad3, Smad7, and TSP1. The latter, TSP1, a co-activator of TGF-β may serve as a suitable biomarker for monitoring the efficacy of halofuginone should it be evaluated in a clinical setting for protection against radiation-induced fibrosis.
fibrosis; TGF-β; radiation; halofuginone; protection
Nitroxides, unlike trityl radicals, have shorter T2s which until now were not detectable by time-domain Electron Paramagnetic Resonance (EPR) spectrometer at 300 MHz pulsed EPR since their phase memory times were shorter than the spectrometer recovery times. In the current version of the time-domain EPR spectrometer with improved spectrometer recovery times, we tested the feasibility of detecting signals from nitroxide radicals. Several nitroxides and the trityl radical Oxo63 were tested. Among the nitroxides evaluated, deuterated 15N-Tempone (15N-PDT) was found to have the longest T2. The signal intensity profile as a function of concentration of these agents was evaluated and a bi-phasic behavior was observed; beyond a nitroxide concentration of 1.5 mM, signal intensity was found to decrease as a result of self-broadening. Imaging experiments were carried out with 15N-PDT in solutions equilibrated with 0, 5, 10 and 21% oxygen using the Single Point Imaging (SPI) modality in EPR. The image intensity in these tubes was found to depend on the oxygen concentration which in turn influences the T2 of 15N-PDT. In vivo experiments were demonstrated with 15N-PDT in anesthetized mice where the distribution and metabolism of 15N-PDT could be monitored. This study, for the first time shows the capability to image a cell-permeable nitroxide in mice using pulsed EPR in the SPI modality.
Nitroxide; Pulsed EPR; Redox; Single Point Imaging
1,3-Butadiene, an important petrochemical, is commonly burned off when excess amounts need to be destroyed. This combustion process produces butadiene soot (BDS), which is composed of a complex mixture of polyaromatic hydrocarbons in particulates ranging in size from <1μm to 1 mm. An organic extract of BDS is both cytotoxic and genotoxic to normal human bronchial epithelial (NHBE) cells. Based on the oxidizing potential of BDS, we hypothesized that an organic extract of this particulate matter would: 1) cause enzyme inactivation due to protein amino acid oxidation; and 2) induce oxidative DNA damage in NHBE cells. Thus, our aims were to determine the effect of butadiene soot ethanol extract (BSEE) on both enzyme activity and expression of proteins involved in the repair of oxidative DNA damage. Catalase was found to be sensitive to BDS as catalase activity was potently diminished in the presence of BSEE. Using Western analysis, both the alpha isoform of human 8-oxoguanine DNA glycosylase (α-hOGG1) and human apurinic/apyrimidinic endonuclease (APE-1) were shown to be significantly overexpressed as compared to untreated controls after exposure of NHBE cells to BSEE. Our results indicate that BSEE is capable of effectively inactivating the antioxidant enzyme catalase, presumably via oxidation of protein amino acids. The presence of oxidized proteins may partially explain the extranuclear fluorescence that is detected when NHBE cells are treated with an organic extract of BDS. Overexpression of both α-hOGG1 and APE-1 proteins following treatment of NHBE cells with BSEE suggests that this mixture causes oxidative DNA damage.
APE-1; Butadiene soot; Catalase; OGG1; Oxidative DNA damage; Oxidative stress
Mortality following bariatric surgery is a rare event in contemporary series, making it difficult for any single center to draw meaningful conclusions as to cause of death. Nevertheless, much of the published mortality data come from single center case series and reviews of administrative databases. These sources tend to produce lower mortality estimates than those obtained from controlled clinical trials. Furthermore, information about the causes of death and how they were determined is not always available. The aim of the present report is to describe in detail all deaths occurring within 30-days of surgery in the Longitudinal Assessment of Bariatric Surgery (LABS).
LABS is a 10-center observational cohort study of bariatric surgical outcomes. Data were collected prospectively for bariatric surgeries performed between March 2005 and April 2009. All deaths occurring within 30-days of surgery were identified, and cause of death assigned by an independent Adjudication Subcommittee, blinded to operating surgeon and site.
6118 patients underwent primary bariatric surgery. 18 deaths (0.3%) occurred within 30-days of surgery. The most common cause of death was sepsis (33% of deaths), followed by cardiac causes (28%) and pulmonary embolism (17%). For one patient cause of death could not be determined despite examination of all available information.
This study confirms the low 30-day mortality rate following bariatric surgery. The recognized complications of anastomotic leak, cardiac events, and pulmonary emboli accounted for the majority of 30-day deaths.
Mortality; Cause of Death; Bariatric Surgery; Gastric Bypass
Structural and functional abnormalities in tumor blood vessels impact the delivery of oxygen and nutrients to solid tumors, resulting chronic and cycling hypoxia. While chronically hypoxic regions exhibit treatment resistance, more recently it has been shown that cycling hypoxic regions acquire pro-survival pathways. Angiogenesis inhibitors have been shown to transiently normalize the tumor vasculatures and enhance tumor response to treatments. However, the effect of anti-angiogenic therapy on cycling tumor hypoxia remains unknown. Using electron paramagnetic resonance imaging (EPRI) and magnetic resonance imaging (MRI) in tumor bearing mice, we have examined the vascular re-normalization process by longitudinally mapping tumor partial pressure of oxygen (pO2) and microvessel density during treatments with a multi-tyrosine kinase inhibitor sunitinib. Transient improvement in tumor oxygenation was visualized by EPRI 2–4 days following anti-angiogenic treatments, accompanied by a 45% decrease in microvessel density. Radiation treatment during this time period of improved oxygenation by anti-angiogenic therapy resulted in a synergistic delay in tumor growth. Additionally, dynamic oxygen imaging obtained every 3 minutes was conducted to distinguish tumor regions with chronic and cycling hypoxia. Sunitinib treatment suppressed the extent of temporal fluctuations in tumor pO2 during the vascular normalization window, resulting in the decrease of cycling tumor hypoxia. Overall, the findings suggest that longitudinal and noninvasive monitoring of tumor pO2 makes it possible to identify a window of vascular renormalization to maximize the effects of combination therapy with anti-angiogenic drugs.
anti-angiogenic therapy; cycling hypoxia; EPR imaging; radiotherapy; vascular normalization
The purpose of this study was to examine the relationship between caloric restriction (CR) and binge eating (BE) using ecological momentary assessment (EMA). Participants included 133 women with bulimia nervosa (BN) who completed an EMA protocol for 2 weeks. Logistic regression analyses tested whether CR increased the probability of BE episodes. The results revealed that the odds of BE increased on the day that restriction occurred as well as on the following day. In addition, both restriction and BE on one day predicted the likelihood of BE the subsequent day, but restriction for two days prior to the episode failed to add additional information for predicting BE. These findings support the cognitive-behavioral therapy (CBT) model of BN, suggesting that self-reported dietary restriction is predictive of subsequent BE episodes, and that reducing dietary restriction in treatment may lead to improvements in bulimic symptoms.
ecological momentary assessment; bulimia nervosa; binge eating; caloric restriction
Follow-up studies of eating disorders (EDs) suggest outcomes ranging from recovery to chronic illness or death, but predictors of outcome have not been consistently identified. We tested 5151 single-nucleotide polymorphisms (SNPs) in approximately 350 candidate genes for association with recovery from ED in 1878 women. Initial analyses focused on a strictly defined discovery cohort of women who were over age 25 years, carried a lifetime diagnosis of an ED, and for whom data were available regarding the presence (n=361 ongoing symptoms in the past year, ie, ‘ill') or absence (n=115 no symptoms in the past year, ie, ‘recovered') of ED symptoms. An intronic SNP (rs17536211) in GABRG1 showed the strongest statistical evidence of association (p=4.63 × 10−6, false discovery rate (FDR)=0.021, odds ratio (OR)=0.46). We replicated these findings in a more liberally defined cohort of women age 25 years or younger (n=464 ill, n=107 recovered; p=0.0336, OR=0.68; combined sample p=4.57 × 10−6, FDR=0.0049, OR=0.55). Enrichment analyses revealed that GABA (γ-aminobutyric acid) SNPs were over-represented among SNPs associated at p<0.05 in both the discovery (Z=3.64, p=0.0003) and combined cohorts (Z=2.07, p=0.0388). In follow-up phenomic association analyses with a third independent cohort (n=154 ED cases, n=677 controls), rs17536211 was associated with trait anxiety (p=0.049), suggesting a possible mechanism through which this variant may influence ED outcome. These findings could provide new insights into the development of more effective interventions for the most treatment-resistant patients.
GABA; anorexia nervosa; recovery from eating disorders; genetic association; single nucleotide polymorphisms; eating/metabolic disorders; GABA; eating/metabolic disorders; neurogenetics; biological psychiatry; genetic association; anorexia nervosa; recovery from eating disorders; single-nucleotide polymorphisms; phenomic association
The recent development of a bi-modality magnetic resonance imaging/electron paramagnetic resonance imaging (MRI/EPRI) platform has enabled longitudinal monitoring of both tumor oxygenation and redox status in murine cancer models. The current study used this imaging platform to test the hypothesis that a more reducing tumor microenvironment accompanies the development of tumor hypoxia. To test this, the redox status of the tumor was measured using Tempol as a redox-sensitive MRI contrast agent, and tumor hypoxia was measured with Oxo63, which is an oxygen-sensitive EPRI spin probe. Images were acquired every 1–2 days in mice bearing SCCVII tumors. The median pO2 decreased from 14 mmHg at 7 days after tumor implantation to 7 mmHg at 15 days after implantation. Additionally, the hypoxic fraction, defined as the percentage of the tumor that exhibited a pO2<10 mmHg, increased with tumor size (from 10% at 500 mm3 to 60% at 3,500 mm3). The rate of Tempol reduction increased as a function of tumor volume (0.4 min−1 at 500 mm3 to 1.7 min−1 at 3,500 mm3), suggesting that the tumor microenvironment became more reduced as the tumor grew. The results show that rapid Tempol reduction correlates with decreased tumor oxygenation, and that the Tempol decay rate constant may be a surrogate marker for tumor hypoxia.
redox status; hypoxia; electron paramagnetic resonance imaging; magnetic resonance imaging; nitroxide; non-invasive imaging; Tempol
Dietary restriction (DR) extends lifespan and increases resistance to multiple forms of stress, including ischemia reperfusion injury to the brain and heart in rodents. While maximal effects on lifespan require long-term restriction, the kinetics of onset of benefits against acute stress are not known. Here we show that 2–4 weeks of 30% dietary restriction improved survival and kidney function following renal ischemia reperfusion injury in mice. Brief periods of water-only fasting were similarly effective at protecting against ischemic damage. Significant protection occurred within one day, persisted for several days beyond the fasting period and extended to another organ, the liver. Protection by both short-term DR and fasting correlated with improved insulin sensitivity, increased expression of markers of antioxidant defense and reduced expression of markers of inflammation and insulin/insulin-like growth factor-1 signaling. Unbiased transcriptional profiling of kidney from mice subject to short-term DR or fasting revealed a significant enrichment of signature genes of long-term DR. These data demonstrate that brief periods of reduced food intake, including short-term daily restriction and fasting, can increase resistance to ischemia reperfusion injury in rodents and suggest a rapid onset of benefits of DR in mammals.
dietary restriction; ischemia reperfusion injury; fasting; oxidative stress; kidney; liver
Individuals are exposed to ionizing radiation during medical procedures and nuclear disasters, and this exposure can be carcinogenic, toxic, and sometimes fatal. Drugs that protect individuals from the adverse effects of radiation may therefore be valuable countermeasures against the health risks of exposure. In the current study, the LD50/30 (the dose resulting in 50% of exposed mice surviving 30 days after exposure) was determined in control C3H mice and mice treated with the nitroxide radioprotectors Tempol, 3-CP, 16c, 22c, and 23c. The pharmacokinetics of 22c and 23c were measured with magnetic resonance imaging (MRI) in the brain, blood, submandibular salivary gland, liver, muscle, tongue, and myocardium. It was found 23c was the most effective radioprotector of the five studied: 23c increased the LD50/30 in mice from 7.9 ± 0.15 Gy (treated with saline) to 11.47 ± 0.13 Gy (an increase of 45%). Additionally, MRI-based pharmacokinetic studies revealed that 23c is an effective redox imaging agent in the mouse brain, and that 23c may allow functional imaging of the myocardium. The data in this report suggest that 23c is currently the most potent known nitroxide radioprotector, and that it may also be useful as a contrast agent for functional imaging.
Radioprotection; Redox Imaging; Blood-Brain-Barrier Permeable Contrast Agents; Nitroxides; Magnetic Resonance Imaging
Gastrointestinal cancers frequently exhibit mutational activation of the Ras/MAPK pathway, which is implicated in resistance to ionizing radiation (IR) and chemotherapy. Concurrent radiotherapy and 5-fluorouracil (5-FU) based chemotherapy is commonly used for treatment of gastrointestinal malignancies. We previously reported radiosensitization with selumetinib, an inhibitor of MEK1/2. The purpose of the current study was to evaluate if selumetinib could enhance radiosensitivity induced by 5-FU.
Clonogenic survival assays were performed with the HT29 (colorectal), HCT116 (colorectal) and MiaPaca-2 (pancreatic) cell lines using pre-IR treatment with selumetinib, 5-FU and 5-FU+selumetinib. Cell proliferation was determined using a tetrazolium conversion assay. Mitotic catastrophe and DNA repair were analyzed using immunocytochemistry. Flow cytometry was used to analyze cell cycle and apoptosis. Growth delay was used to determine effects of 5-FU+selumetinib on in vivo tumor radiosensitivity.
Pre-IR treatment with 5-FU+selumetinib significantly decreased clonogenic survival compared to either agent alone. Dose modifying factors at a surviving fraction of 0.1 for 5-FU+selumetinib was 1.78, 1.52, and 1.3 for HT29, HCT116, and MiaPaca-2, respectively. Cell proliferation was decreased by treatment with selumetinib+5-FU as compared to single agent treatment regardless of treatment sequencing. Enhancement of 5-FU cytotoxicity and 5-FU mediated radiosensitization with selumetinib treatment was accompanied by an increase in mitotic catastrophe and apoptosis, and reductions in Stat3 phosphorylation and survivin expression. In vivo, an additive growth delay was observed with 5-FU+selumetinib+5Gy versus 5-FU+5Gy and selumetinib alone.
These data suggest that selumetinib can be used with 5-FU to augment radiation response.
selumetinib; AZD6244; 5-fluorouracil; radiosensitization; MEK1/2
Sexually transmitted infections (STIs) are associated with an increased risk of HIV infection. To model the interaction between STIs and HIV infection, we evaluated the capacity of the pigtail macaque model to sustain triple infection with Trichomonas vaginalis, Chlamydia trachomatis, and SHIVSF162P3.
Seven SHIVSF162P3-infected pigtail macaques were inoculated with T. vaginalis only (n = 2), C. trachomatis only (n = 1), both T. vaginalis and C. trachomatis (n = 2), or control media (no STI; n = 2). Infections were confirmed by culture and/or nucleic acid testing. Genital mucosa was visualized by colposcopy.
Characteristic gynecologic signs were observed for both STIs, but not in control animals. Manifestations were most prominent at days 7–10 post-infection. STIs persisted between 4 and 6 weeks and were cleared with antibiotics.
These pilot studies demonstrate the first successful STI-SHIV triple infection of pigtail macaques, with clinical presentation of genital STI symptoms similar to those observed in humans.
coinfection; genital; mucosal; non-human primate
There is growing evidence that obesity is associated with poor neurocognitive outcome. Bariatric surgery is an effective intervention for morbid obesity and improves many comorbid medical conditions that are associated with cognitive dysfunction. The effects of bariatric surgery on cognition are unknown.
Prospective study total of 150 individuals (109 bariatric surgery patients enrolled in the Longitudinal Assessment of Bariatric Surgery (LABS) project and 41 obese controls that did not undergo surgery) completed cognitive evaluation at baseline and 12 week follow-up. Demographic, medical, and psychosocial information was also collected to elucidate possible mechanisms of change.
Many bariatric surgery patients exhibited impaired performance on cognitive testing at baseline (range from 4.6%–23.9%). However, surgery patients were no more likely to exhibit decline on two or more cognitive tests at 12-week follow-up than obese controls [12.84% vs. 23.26%; χ2 (1) = 2.51, p = .11]. Group comparisons using repeated measures MANOVA showed surgery patients had improved memory performance at 12 week follow-up [λ = .86, F(4, 147) = 5.88, p<.001], whereas obese controls actually declined. Regression analyses showed surgery patients without hypertension had better short delay recall at 12 weeks than those that did [β = 0.31, p = .005], though other demographic and medical variables were largely unrelated to test performance.
The current results suggest that cognitive impairment is common in bariatric surgery patients, though these deficits may be at least partly reversible. Future studies are needed to clarify underlying mechanisms, particularly longitudinal studies employing neuroimaging and blood markers.
obesity; cognitive function; bariatric surgery; Integneuro
Comorbidity among eating disorders, traumatic events, and post traumatic stress disorder (PTSD) has been reported in several studies. The main objectives of this study were to describe the nature of traumatic events experienced and to explore the relation between PTSD and anorexia nervosa (AN) in a sample of women.
Eight hundred twenty-four participants from the National Institutes of Health funded Genetics of Anorexia Nervosa Collaborative Study were assessed for eating disorders, PTSD, and personality characteristics.
From a final sample of 753 women with AN, 13.7% (n=103) met DSM-IV criteria for PTSD. The sample mean age was 29.5 years (SD=11.1). In pairwise comparisons across AN subtypes, the odds of having a PTSD diagnosis were significantly lower in individuals with restricting AN (RAN) than individuals with purging AN without binge eating (PAN) (OR=0.49, 95% CI=0.30, 0.80). The majority of participants with PTSD reported the first traumatic event before the onset of AN (64.1%, n=66). The most common traumatic events reported by those with a PTSD diagnosis were sexual related traumas during childhood (40.8%) and during adulthood (35.0%).
AN and PTSD do co-occur and traumatic events tend to occur prior to the onset of AN. Clinically, these results underscore the importance of assessing trauma history and PTSD in individuals with AN and raise the question of whether specific modifications or augmentations to standard treatment for AN should be considered in a subgroup to address PTSD-related psychopathology.
PTSD; anorexia nervosa; trauma; prevalence; comorbid; epigenetic
Metagenomic analysis was used to examine the taxonomic diversity and metabolic potential of an Australian sea lion (Neophoca cinerea) gut microbiome. Bacteria comprised 98% of classifiable sequences and of these matches to Firmicutes (80%) were dominant, with Proteobacteria and Actinobacteria representing 8% and 2% of matches respectively. The relative proportion of Firmicutes (80%) to Bacteriodetes (2%) is similar to that in previous studies of obese humans and obese mice, suggesting the gut microbiome may confer a predisposition towards the excess body fat that is needed for thermoregulation within the cold oceanic habitats foraged by Australian sea lions. Core metabolic functions, including carbohydrate utilisation (14%), protein metabolism (9%) and DNA metabolism (7%) dominated the metagenome, but in comparison to human and fish gut microbiomes there was a significantly higher proportion of genes involved in phosphorus metabolism (2.4%) and iron scavenging mechanisms (1%). When sea lions defecate at sea, the relatively high nutrient metabolism potential of bacteria in their faeces may accelerate the dissolution of nutrients from faecal particles, enhancing their persistence in the euphotic zone where they are available to stimulate marine production.