Postradioiodine Graves' management: The PRAGMA study.

OBJECTIVE: Thyroid status in the months following radioiodine (RI) treatment for Graves' disease can be unstable. Our objective was to quantify frequency of abnormal thyroid function post-RI and compare effectiveness of common management strategies. DESIGN: Retrospective, multicentre and observational study. PATIENTS: Adult patients with Graves' disease treated with RI with 12 months' follow-up. MEASUREMENTS: Euthyroidism was defined as both serum thyrotropin (thyroid-stimulating hormone [TSH]) and free thyroxine (FT4) within their reference ranges or, when only one was available, it was within its reference range; hypothyroidism as TSH ≥ 10 mU/L, or subnormal FT4 regardless of TSH; hyperthyroidism as TSH below and FT4 above their reference ranges; dysthyroidism as the sum of hypo- and hyperthyroidism; subclinical hypothyroidism as normal FT4 and TSH between the upper limit of normal and <10 mU/L; and subclinical hyperthyroidism as low TSH and normal FT4. RESULTS: Of 812 patients studied post-RI, hypothyroidism occurred in 80.7% and hyperthyroidism in 48.6% of patients. Three principal post-RI management strategies were employed: (a) antithyroid drugs alone, (b) levothyroxine alone, and (c) combination of the two. Differences among these were small. Adherence to national guidelines regarding monitoring thyroid function in the first 6 months was low (21.4%-28.7%). No negative outcomes (new-onset/exacerbation of Graves' orbitopathy, weight gain, and cardiovascular events) were associated with dysthyroidism. There were significant differences in demographics, clinical practice, and thyroid status postradioiodine between centres. CONCLUSIONS: Dysthyroidism in the 12 months post-RI was common. Differences between post-RI strategies were small, suggesting these interventions alone are unlikely to address the high frequency of dysthyroidism.

Compact multispectral pushframe camera for nanosatellites.

In this paper we present an evolution of the single-pixel camera architecture, called "pushframe," which addresses the limitations of pushbroom cameras in space-based applications. In particular, it is well-suited to observing fast-moving scenes while retaining high spatial resolution and sensitivity. We show that the system is capable of producing color images with good fidelity and scalable resolution performance. The principle of our design broadens the choice of spectral ranges that can be captured, making it suitable for wide spectral ranges of infrared imaging.

Regulation of glycine metabolism by the glycine cleavage system and conjugation pathway in mouse models of non-ketotic hyperglycinemia.

Glycine abundance is modulated in a tissue-specific manner by use in biosynthetic reactions, catabolism by the glycine cleavage system (GCS), and excretion via glycine conjugation. Dysregulation of glycine metabolism is associated with multiple disorders including epilepsy, developmental delay, and birth defects. Mutation of the GCS component glycine decarboxylase (GLDC) in non-ketotic hyperglycinemia (NKH) causes accumulation of glycine in body fluids, but there is a gap in our knowledge regarding the effects on glycine metabolism in tissues. Here, we analysed mice carrying mutations in Gldc that result in severe or mild elevations of plasma glycine and model NKH. Liver of Gldc-deficient mice accumulated glycine and numerous glycine derivatives, including multiple acylglycines, indicating increased flux through reactions mediated by enzymes including glycine-N-acyltransferase and arginine: glycine amidinotransferase. Levels of dysregulated metabolites increased with age and were normalised by liver-specific rescue of Gldc expression. Brain tissue exhibited increased abundance of glycine, as well as derivatives including guanidinoacetate, which may itself be epileptogenic. Elevation of brain tissue glycine occurred even in the presence of only mildly elevated plasma glycine in mice carrying a missense allele of Gldc. Treatment with benzoate enhanced hepatic glycine conjugation thereby lowering plasma and tissue glycine. Moreover, administration of a glycine conjugation pathway intermediate, cinnamate, similarly achieved normalisation of liver glycine derivatives and circulating glycine. Although exogenous benzoate and cinnamate impact glycine levels via activity of glycine-N-acyltransferase, that is not expressed in brain, they are sufficient to lower levels of glycine and derivatives in brain tissue of treated Gldc-deficient mice.

Adaptation of Syntenic Xyloglucan Utilization Loci of Human Gut Bacteroidetes to Polysaccharide Side Chain Diversity.

Genome sequencing has revealed substantial variation in the predicted abilities of individual species within animal gut microbiota to metabolize the complex carbohydrates comprising dietary fiber. At the same time, a currently limited body of functional studies precludes a richer understanding of how dietary glycan structures affect the gut microbiota composition and community dynamics. Here, using biochemical and biophysical techniques, we identified and characterized differences among recombinant proteins from syntenic xyloglucan utilization loci (XyGUL) of three Bacteroides and one Dysgonomonas species from the human gut, which drive substrate specificity and access to distinct polysaccharide side chains. Enzymology of four syntenic glycoside hydrolase family 5 subfamily 4 (GH5_4) endo-xyloglucanases revealed surprising differences in xyloglucan (XyG) backbone cleavage specificity, including the ability of some homologs to hydrolyze congested branched positions. Further, differences in the complement of GH43 alpha-l-arabinofuranosidases and GH95 alpha-l-fucosidases among syntenic XyGUL confer distinct abilities to fully saccharify plant species-specific arabinogalactoxyloglucan and/or fucogalactoxyloglucan. Finally, characterization of highly sequence-divergent cell surface glycan-binding proteins (SGBPs) across syntenic XyGUL revealed a novel group of XyG oligosaccharide-specific SGBPs encoded within select BacteroidesIMPORTANCE The catabolism of complex carbohydrates that otherwise escape the endogenous digestive enzymes of humans and other animals drives the composition and function of the gut microbiota. Thus, detailed molecular characterization of dietary glycan utilization systems is essential both to understand the ecology of these complex communities and to manipulate their compositions, e.g., to benefit human health. Our research reveals new insight into how ubiquitous members of the human gut microbiota have evolved a set of microheterogeneous gene clusters to efficiently respond to the structural variations of plant xyloglucans. The data here will enable refined functional prediction of xyloglucan utilization among diverse environmental taxa in animal guts and beyond.

Age-associated changes in long-chain fatty acid profile during healthy aging promote pro-inflammatory monocyte polarization via PPARγ.

Differences in lipid metabolism associate with age-related disease development and lifespan. Inflammation is a common link between metabolic dysregulation and aging. Saturated fatty acids (FAs) initiate pro-inflammatory signalling from many cells including monocytes; however, no existing studies have quantified age-associated changes in individual FAs in relation to inflammatory phenotype. Therefore, we have determined the plasma concentrations of distinct FAs by gas chromatography in 26 healthy younger individuals (age < 30 years) and 21 healthy FA individuals (age > 50 years). Linear mixed models were used to explore the association between circulating FAs, age and cytokines. We showed that plasma saturated, poly- and mono-unsaturated FAs increase with age. Circulating TNF-α and IL-6 concentrations increased with age, whereas IL-10 and TGF-ß1 concentrations decreased. Oxidation of MitoSOX Red was higher in leucocytes from FA adults, and plasma oxidized glutathione concentrations were higher. There was significant colinearity between plasma saturated FAs, indicative of their metabolic relationships. Higher levels of the saturated FAs C18:0 and C24:0 were associated with lower TGF-ß1 concentrations, and higher C16:0 were associated with higher TNF-α concentrations. We further examined effects of the aging FA profile on monocyte polarization and metabolism in THP1 monocytes. Monocytes preincubated with C16:0 increased secretion of pro-inflammatory cytokines in response to phorbol myristate acetate-induced differentiation through ceramide-dependent inhibition of PPARγ activity. Conversely, C18:1 primed a pro-resolving macrophage which was PPARγ dependent and ceramide dependent and which required oxidative phosphorylation. These data suggest that a midlife adult FA profile impairs the switch from proinflammatory to lower energy, requiring anti-inflammatory macrophages through metabolic reprogramming.

CD4(+) T cell surface alpha enolase is lower in older adults.

To identify novel cell ageing markers in order to gain insight into ageing mechanisms, we adopted membrane enrichment and comparison of the CD4(+) T cell membrane proteome (purified by cell surface labelling using Sulfo-NHS-SS-Biotin reagent) between healthy young (n=9, 20-25 years) and older (n=10; 50-70 years) male adults. Following two-dimensional gel electrophoresis (2DE) to separate pooled membrane proteins in triplicates, the identity of protein spots with age-dependent differences (p<0.05 and >1.4 fold difference) was determined using liquid chromatography-mass spectrometry (LC-MS/MS). Seventeen protein spot density differences (ten increased and seven decreased in the older adult group) were observed between young and older adults. From spot intensity analysis, CD4(+) T cell surface α-enolase was decreased in expression by 1.5 fold in the older age group; this was verified by flow cytometry (n=22) and qPCR with significantly lower expression of cellular α-enolase mRNA and protein compared to young adult CD4(+) T cells (p<0.05). In an independent age-matched case-control study, lower CD4(+) T cell surface α-enolase expression was observed in age-matched patients with cardiovascular disease (p<0.05). An immune-modulatory role has been proposed for surface α-enolase and our findings of decreased expression suggest that deficits in surface α-enolase merit investigation in the context of immune dysfunction during ageing and vascular disease.

Thioredoxin as a putative biomarker and candidate target in age-related immune decline.

The oxidoreductase Trx-1 (thioredoxin 1) is highly conserved and found intra- and extra-cellularly in mammalian systems. There is increasing interest in its capacity to regulate immune function based on observations of altered distribution and expression during ageing and disease. We have investigated previously whether extracellular T-cell or peripheral blood mononuclear cell Trx-1 levels serve as a robust marker of ageing. In a preliminary study of healthy older adults compared with younger adults, we showed that there was a significant, but weak, relationship with age. Interestingly, patients with rheumatoid arthritis and cancer have been described by others to secrete or express greater surface Trx-1 than predicted. It is interesting to speculate whether a decline in Trx-1 during ageing protects against such conditions, but correspondingly increases risk of disease associated with Trx-1 depletion such as cardiovascular disease. These hypotheses are being explored in the MARK-AGE study, and preliminary findings confirm an inverse correlation of surface Trx-1 with age. We review recent concepts around the role of Trx-1 and its partners in T-cell function on the cell surface and as an extracellular regulator of redox state in a secreted form. Further studies on the redox state and binding partners of surface and secreted Trx-1 in larger patient datasets are needed to improve our understanding of why Trx-1 is important for lifespan and immune function.

Ultra-endurance exercise: unanswered questions in redox biology and immunology.

Ultra-endurance races are extreme exercise events that can take place over large parts of a day, several consecutive days or over weeks and months interspersed by periods of rest and recovery. Since the first ultra-endurance races in the late 1970s, around 1000 races are now held worldwide each year, and more than 100000 people take part. Although these athletes appear to be fit and healthy, there have been occasional reports of severe complications following ultra-endurance exercise. Thus there is concern that repeated extreme exercise events could have deleterious effects on health, which might be brought about by the high levels of ROS (reactive oxygen species) produced during exercise. Studies that have examined biomarkers of oxidative damage following ultra-endurance exercise have found measurements to be elevated for several days, which has usually been interpreted to reflect increased ROS production. Levels of the antioxidant molecule GSH (reduced glutathione) are depleted for 1 month or longer following ultra-endurance exercise, suggesting an impaired capacity to cope with ROS. The present paper summarizes studies that have examined the oxidative footprint of ultra-endurance exercise in light of current thinking in redox biology and the possible health implications of such extreme exercise.

Mass spectrometric characterization of circulating covalent protein adducts derived from a drug acyl glucuronide metabolite: multiple albumin adductions in diclofenac patients.

Covalent protein modifications by electrophilic acyl glucuronide (AG) metabolites are hypothetical causes of hypersensitivity reactions associated with certain carboxylate drugs. The complex rearrangements and reactivities of drug AG have been defined in great detail, and protein adducts of carboxylate drugs, such as diclofenac, have been found in liver and plasma of experimental animals and humans. However, in the absence of definitive molecular characterization, and specifically, identification of signature glycation conjugates retaining the glucuronyl and carboxyl residues, it cannot be assumed any of these adducts is derived uniquely or even fractionally from AG metabolites. We have therefore undertaken targeted mass spectrometric analyses of human serum albumin (HSA) isolated from diclofenac patients to characterize drug-: derived structures and, thereby, for the first time, have deconstructed conclusively the pathways of adduct formation from a drug AG and its isomeric rearrangement products in vivo. These analyses were informed by a thorough understanding of the reactions of HSA with diclofenac AG in vitro. HSA from six patients without drug-: related hypersensitivities had either a single drug-: derived adduct or one of five combinations of 2-8 adducts from among seven diclofenac N-acylations and three AG glycations on seven of the protein's 59 lysines. Only acylations were found in every patient. We present evidence that HSA modifications by diclofenac in vivo are complicated and variable, that at least a fraction of these modifications are derived from the drug's AG metabolite, and that albumin adduction is not inevitably a causation of hypersensitivity to carboxylate drugs or a coincidental association.

Does metabolic reprogramming underpin age-associated changes in T cell phenotype and function?

T cells are required for an effective adaptive immune response. The principal function of T cells is to promote efficient removal of foreign material by identifying and mounting a specific response to nonself. A decline in T cell function in aging is thought to contribute to reduced response to infection and vaccination and an increase in autoimmunity. This may in part be due to the age-related decrease in naïve CD4(+) T cells and increase in antigen-experienced CD4(+) T cells, loss of redox homeostasis, and impaired metabolic switching. Switching between subsets is triggered by the integration of extracellular signals sensed through surface receptors and the activation of discrete intracellular metabolic pathways. This article explores how metabolic programming and loss of redox homeostasis during aging may contribute to age-associated changes in T cell phenotype and function.

Measurement of HNE-protein adducts in human plasma and serum by ELISA-Comparison of two primary antibodies.

There is increasing evidence that non-enzymatic post-translational protein modifications might play key roles in various diseases. These protein modifications can be caused by free radicals generated during oxidative stress or by their products generated during lipid peroxidation. 4-Hydroxynonenal (HNE), a major biomarker of oxidative stress and lipid peroxidation, has been recognized as important molecule in pathology as well as in physiology of living organisms. Therefore, its detection and quantification can be considered as valuable tool for evaluating various pathophysiological conditions. The HNE-protein adduct ELISA is a method to detect HNE bound to proteins, which is considered as the most likely form of HNE occurrence in living systems. Since the earlier described ELISA has been validated for cell lysates and the antibody used for detection of HNE-protein adducts is non-commercial, the aim of this work was to adapt the ELISA to a commercial antibody and to apply it in the analysis of human plasma samples. AFTER MODIFICATION AND VALIDATION OF THE PROTOCOL FOR BOTH ANTIBODIES, SAMPLES OF TWO GROUPS WERE ANALYZED: apparently healthy obese (n=62) and non-obese controls (n=15). Although the detected absolute values of HNE-protein adducts were different, depending on the antibody used, both ELISA methods showed significantly higher values of HNE-protein adducts in the obese group.

Healthy ageing and depletion of intracellular glutathione influences T cell membrane thioredoxin-1 levels and cytokine secretion.

BACKGROUND: During ageing an altered redox balance has been observed in both intracellular and extracellular compartments, primarily due to glutathione depletion and metabolic stress. Maintaining redox homeostasis is important for controlling proliferation and apoptosis in response to specific stimuli for a variety of cells. For T cells, the ability to generate specific response to antigen is dependent on the oxidation state of cell surface and cytoplasmic protein-thiols. Intracellular thiols are maintained in their reduced state by a network of redox regulating peptides, proteins and enzymes such as glutathione, thioredoxins and thioredoxin reductase. Here we have investigated whether any relationship exists between age and secreted or cell surface thioredoxin-1, intracellular glutathione concentration and T cell surface thioredoxin 1 (Trx-1) and how this is related to interleukin (IL)-2 production. RESULTS: Healthy older adults have reduced lymphocyte surface expression and lower circulating plasma Trx-1 concentrations. Using buthionine sulfoximine to deplete intracellular glutathione in Jurkat T cells we show that cell surface Trx-1 is lowered, secretion of Trx-1 is decreased and the response to the lectin phytohaemagglutinin measured as IL-2 production is also affected. These effects are recapitulated by another glutathione depleting agent, diethylmaleate. CONCLUSION: Together these data suggest that a relationship exists between the intracellular redox compartment and Trx-1 proteins. Loss of lymphocyte surface Trx-1 may be a useful biomarker of healthy ageing.

Free-Wilson and structural approaches to co-optimizing human and rodent isoform potency for 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) inhibitors.

11ß-Hydroxysteroid dehydrogenase 1 (11ß-HSD1) has been a target of intensive research efforts across the pharmaceutical industry, due to its potential for the treatment of type II diabetes and other elements of the metabolic syndrome. To demonstrate the value of 11ß-HSD1 in preclinical models, we required inhibitors with good potency against both human and rodent isoforms. Herein, we describe our efforts to understand how to co-optimize human and murine potency within the (5-hydroxy-2-adamantyl)-pyrimidine-5-carboxamide series. Two approaches are described-a data-driven (Free-Wilson) analysis and a structure-based design approach. The conclusions from these approaches were used to inform an efficient campaign to design compounds with consistently good human/murine potency within a logD(7.4) range of 1-3. Compounds 20 and 26 demonstrated good rodent PK, which allowed us to demonstrate a PK/PD relationship in rat and mouse. We then evaluated 26 against glycemic and body weight end points in murine disease models, where it demonstrated glucose and body weight efficacy at 300 mg/kg/day but only body weight efficacy at 50 mg/kg/day, despite providing >90% target engagement in the liver.

Adrenal steroidogenesis after B lymphocyte depletion therapy in new-onset Addison's disease.

CONTEXT: A diagnosis of Addison's disease means lifelong dependence on daily glucocorticoid and mineralocorticoid therapy and is associated with increased morbidity and mortality as well as a risk of unexpected adrenal crisis. OBJECTIVE: The objective of the study was to determine whether immunomodulatory therapy at an early stage of autoimmune Addison's disease could lead to preservation or improvement in adrenal steroidogenesis. DESIGN AND INTERVENTION: This was an open-label, pilot study of B lymphocyte depletion therapy in new-onset idiopathic primary adrenal failure. Doses of iv rituximab (1 g) were given on d 1 and 15, after pretreatment with 125 mg iv methylprednisolone. PATIENTS AND MAIN OUTCOME MEASURES: Six patients (aged 17-47 yr; four females) were treated within 4 wk of the first diagnosis of idiopathic primary adrenal failure. Dynamic testing of adrenal function was performed every 3 months for at least 12 months. RESULTS: Serum cortisol levels declined rapidly and were less than 100 nmol/liter (3.6 µg/dl) in all patients by 3 months after B lymphocyte depletion. Serum cortisol and aldosterone concentrations remained low in five of the six patients throughout the follow-up period. However, a single patient had sustained improvement in both serum cortisol [peak 434 nmol/liter (15.7 µg/dl)] and aldosterone [peak 434 pmol/liter (15.7 ng/dl)] secretion. This patient was able to discontinue steroid medications 15 months after therapy and remains well, with improving serum cortisol levels 27 months after therapy. CONCLUSION: New-onset autoimmune Addison's disease should be considered as a potentially reversible condition in some patients. Future studies of immunomodulation in autoimmune Addison's disease may be warranted.

Plasma levels of complement 4a protein are increased in Alzheimer's disease.

Alzheimer's disease (AD) is a devastating neurodegenerative disorder that has been predicted to affect 106.2 million people worldwide by 2050. Currently, definitive diagnosis for this disease is given post mortem, and there is a need for biomarker identification to enable earlier diagnosis of this disease. Biomarkers of AD would ideally represent early disease process and will be present in peripheral tissue before cognitive decline develops in this population. Proteomic technologies offer a strategy to undertake such work. In recent times, research in this field has moved away from classical 2-dimensional gel-based proteomics toward more sensitive, non-gel-based proteomic methodologies. In the study presented here, isobaric labeling for relative and absolute quantification was used to assess plasma protein expression in a small group of AD and control samples. Several proteins were identified as being differentially expressed between these 2 populations. Complement 4a plasma protein was identified as increased in AD by isobaric labeling for relative and absolute quantification, and this finding was further validated by Western blotting and enzyme-linked immunosorbent assay. These data suggest that inflammatory processes, which have been shown to be involved in AD pathology in the brain, are also present in plasma.

Free radicals and redox signalling in T-cells during chronic inflammation and ageing.

During chronic inflammation and ageing, the increase in oxidative stress in both intracellular and extracellular compartments is likely to influence local cell functions. Redox changes alter the T-cell proteome in a quantitative and qualitative manner, and post-translational modifications to surface and cytoplasmic proteins by increased reactive species can influence T-cell function. Previously, we have shown that RA (rheumatoid arthritis) T-cells exhibit reduced ROS (reactive oxygen species) production in response to extracellular stimulation compared with age-matched controls, and basal ROS levels [measured as DCF (2',7'-dichlorofluorescein) fluorescence] are lower in RA T-cells. In contrast, exposing T-cells in vitro to different extracellular redox environments modulates intracellular signalling and enhances cytokine secretion. Together, these data suggest that a complex relationship exists between intra- and extra-cellular redox compartments which contribute to the T-cell phenotype.

Discovery of a series of indan carboxylic acid glycogen phosphorylase inhibitors.

A series of carboxylic acid glycogen phosphorylase inhibitors, which have potential as oral antidiabetic agents, is described. Defining and applying simple physicochemical design criteria was used to assess the opportunity and to focus synthetic efforts on compounds with the greatest probability of success. The study led to compound 17, which exhibits a good balance of properties including potent inhibition of recombinant human liver glycogen phosphorylase in vitro, a good DMPK profile including excellent bioavailability and low clearance and good in vivo activity in a glucagon challenge model of diabetes in Zucker rats.

Increased low-density lipoprotein oxidation, but not total plasma protein oxidation, in Alzheimer's disease.

OBJECTIVES: The two most common forms of dementia are Alzheimer's disease (AD), and vascular dementia (VaD). In the overlap of biochemical processes which have been identified in AD and VaD, oxidative stress is believed to contribute to the numerous pathologies of both dementias. DESIGN AND METHODS: This study assessed oxidative damage in total plasma proteins, and isolated LDL in AD patients and age matched controls, in addition total antioxidant capacity (TAC) was measured. RESULTS: Significantly higher LDL protein carbonylation was observed in AD compared to age-matched controls (AD: 4.17+/-0.73 vs. control: 3.85+/-0.86 nmol/mg LDL; p=0.05, 2-tailed Mann-Whitney), in addition to reduced TAC (AD: 924.708+/-174.429 vs. control: 1078.536+/-252.633 microM; p=0.001, 2-tailed Mann-Whitney). No differences were seen in total plasma protein carbonyl content (AD: 3.88+/-0.31 vs. control: 3.98+/-0.48 nmol/mg protein). CONCLUSION: The results further support the view that oxidation events in AD may be specific in nature, and represent functional changes to proteins, rather than random global events.

Oxidative stress in vascular dementia and Alzheimer's disease: a common pathology.

Alzheimer's disease and vascular dementia are the two most common types of dementia with the former being the most predominant. It is evident that oxidative stress, an environment where pro-oxidant species overwhelm antioxidant species, is involved in the pathogenesis of both forms of dementia. An increased level of reactive oxygen species in the vasculature, reduced nitric oxide bioavailability, and endothelial dysfunction leading to vascular disease is associated with vascular dementia. In Alzheimer's disease, an increased amount of amyloid-beta peptide induces elevated reactive oxygen species production thereby causing neuronal cell death and damage. The recent observation that increased atherosclerotic plaque formation is present in the main artery to the brain in Alzheimer's disease, coupled with the association of vascular risk factors with this disease, suggests a link between these two dementias. This review will argue that Alzheimer's disease and vascular dementia are two extremes of one disease, thus assuming a hypothesis where the clinical conditions referred to as dementia are part of a continuum. We propose that the majority of cases share a vascular pathology and that oxidative stress is central to this common pathology.