Inhibition of fatty acid oxidation enables heart regeneration in adult mice

Postnatal maturation of cardiomyocytes is characterized by a metabolic switch from glycolysis to fatty acid oxidation, chromatin reconfiguration and exit from the cell cycle, instating a barrier for adult heart regeneration. Here, to explore whether metabolic reprogramming can overcome this barrier and enable heart regeneration, we abrogate fatty acid oxidation in cardiomyocytes by inactivation of Cpt1b. We find that disablement of fatty acid oxidation in cardiomyocytes improves resistance to hypoxia and stimulates cardiomyocyte proliferation, allowing heart regeneration after ischaemia-reperfusion injury. Metabolic studies reveal profound changes in energy metabolism and accumulation of α-ketoglutarate in Cpt1b-mutant cardiomyocytes, leading to activation of the α-ketoglutarate-dependent lysine demethylase KDM5. Activated KDM5 demethylates broad H3K4me3 domains in genes that drive cardiomyocyte maturation, lowering their transcription levels and shifting cardiomyocytes into a less mature state, thereby promoting proliferation. We conclude that metabolic maturation shapes the epigenetic landscape of cardiomyocytes, creating a roadblock for further cell divisions. Reversal of this process allows repair of damaged hearts

Design, baseline characteristics, and retention of African American light smokers into a randomized trial involving biological data

<p>Abstract</p> <p>Background</p> <p>African Americans experience significant tobacco-related health disparities despite the fact that over half of African American smokers are light smokers (use ≤10 cigarettes per day). African Americans have been under-represented in smoking cessation research, and few studies have evaluated treatment for light smokers. This paper describes the study design, measures, and baseline characteristics from <it>Kick It at Swope III </it>(KIS-III), the first treatment study of bupropion for African American light smokers.</p> <p>Methods</p> <p>Five hundred forty African American light smokers were randomly assigned to receive bupropion (150mg bid) (n = 270) or placebo (n = 270) for 7 weeks. All participants received written materials and health education counseling. Participants responded to survey items and provided blood samples for evaluation of phenotype and genotype of CYP2A6 and CYP2B6 enzymes involved in nicotine and bupropion metabolism. Primary outcome was cotinine-verified 7-day point prevalence smoking abstinence at Week 26 follow-up.</p> <p>Results</p> <p>Of 2,628 individuals screened, 540 were eligible, consented, and randomized to treatment. Participants had a mean age of 46.5 years and 66.1% were women. Participants smoked an average of 8.0 cigarettes per day, had a mean exhaled carbon monoxide of 16.4ppm (range 1-55) and a mean serum cotinine of 275.8ng/ml. The mean Fagerström Test for Nicotine Dependence was 3.2, and 72.2% of participants smoked within 30 minutes of waking. The average number of quit attempts in the past year was 3.7 and 24.2% reported using pharmacotherapy in their most recent quit attempt. Motivation and confidence to quit were high.</p> <p>Conclusion</p> <p>KIS-III is the first study designed to examine both nicotine and bupropion metabolism, evaluating CYP2A6 and CYP2B6 phenotype and genotype in conjunction with psychosocial factors, in the context of treatment of African American light smokers. Of 1629 smokers screened for study participation, only 18 (1.1%) were ineligible to participate in the study because they refused blood draws, demonstrating the feasibility of recruiting and enrolling African American light smokers into a clinical treatment trial involving biological data collection and genetic analyses. Future evaluation of individual factors associated with treatment outcome will contribute to advancing tailored tobacco use treatment with the goal of enhancing treatment and reducing health disparities for African American light smokers.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="URL">NCT00666978</a></p

Metabolite ratios as potential biomarkers for type 2 diabetes:a DIRECT study

Aims/hypothesis Circulating metabolites have been shown to reflect metabolic changes during the development of type 2 diabetes. In this study we examined the association of metabolite levels and pairwise metabolite ratios with insulin responses after glucose, glucagon-like peptide-1 (GLP-1) and arginine stimulation. We then investigated if the identified metabolite ratios were associated with measures of OGTT-derived beta cell function and with prevalent and incident type 2 diabetes. Methods We measured the levels of 188 metabolites in plasma samples from 130 healthy members of twin families (from the Netherlands Twin Register) at five time points during a modified 3 h hyperglycaemic clamp with glucose, GLP-1 and arginine stimulation. We validated our results in cohorts with OGTT data (n = 340) and epidemiological case–control studies of prevalent (n = 4925) and incident (n = 4277) diabetes. The data were analysed using regression models with adjustment for potential confounders. Results There were dynamic changes in metabolite levels in response to the different secretagogues. Furthermore, several fasting pairwise metabolite ratios were associated with one or multiple clamp-derived measures of insulin secretion (all p Conclusion/interpretation In this study we have shown that the Val_PC ae C32:2 metabolite ratio is associated with an increased risk of type 2 diabetes and measures of insulin secretion and resistance. The observed effects were stronger than that of the individual metabolites and independent of known risk factors.</p

Targeted metabolomics of dried blood spot extracts.

Dried blood spot (DBS) samples are already successfully used in newborn screening and pharmacological analyses. The application of DBS matrix to further metabolomic methods will considerably extend the analytical options for the diagnostics of metabolic diseases. We present an MS/MS based method for the simultaneous extraction and quantification of 188 metabolites from dried blood spots. We provide a sensitive and reproducible method that adapts the Absolute IDQ&trade; p180 kit of Biocrates to the DBS matrix for the quantification of metabolites of different substance classes including amino acids, biogenic amines, free carnitine, acylcarnitines, hexoses, glycerophospholipids, lysophosphatidylcholines, phosphatidylcholines, and sphingolipids

Timing, togetherness and time windfalls

Eine Analyse der Zeitnutzung, des Arbeitskraefteangebots und der Freizeit kann ueber die uebliche Standardfrage nach der Lohn- und Einkommenselastizitaet im Verhaeltnis zu geleisteten Arbeitstunden hinausfuehren. 1. Ein Modell eines implizites Marktes fuer Arbeitszeiten zu unterschiedlichen Tageszeiten zeigt auf der Grundlage von amerikanischen Daten von 1973-1997, dass der Anteil an Abend- oder Nachtschichten abgenommen hat. 2. Die gleichen Daten belegen, dass Arbeitnehmer, deren relatives Einkommen stieg, weniger Arbeitsstress bei ungewoehnlichen Arbeitszeiten verspueren. 3. US-Daten in den 70er und 90er Jahren zeigen synchrone Arbeitszeitregelung zwischen Ehepartnern. Diese nahmen jedoch nach den 70ern wieder ab. Die Nachfrageelastitzitaet nach vollem Einkommen war bei Ehefrauen in den 70ern hoeher und bei Ehefrauen und Ehemaennern in den 90ern gleich. 4. Niederlaendische Zeitbudget-Daten aus dem Jahr 1990 zeigen auf, dass die ueberwiegende Mehrheit des Zeitgewinns fuer zusaetzlichen Schlaf genutzt wurde, ausser bei maennlichen Singles, die ihre zusaetzliche Freizeit fuer Sportaktivitaeten und Fernsehen einsetzten. (ICCUeBERS)'By examples this study illustrates that with the right data the analysis of time use, labor supply and leisure can and should move beyond the standard questions of the wage and income elasticities of hours supplied to the market. Four examples are presented here: 1. a model of the implicit market for working at different times of the day. Using American data from 1973 through 1997 the author shows that, following the prediction of the model, the amount of evening and night work in the U.S. has decreased; 2. using the same model, the prediction that groups whose relative earnings have increased will experience a relative diminution of the burden of working at unpleasant times is verified using the same American data; 3. to study spouses' consumption of leisure one must study its temporal distribution, not how it is integrated over some long interval. Using U.S. data for the 1970s and 1990s the author demonstrates that spouses' work schedules are more contemporaneous than would occur randomly, that contemporaneity among working spouses has diminished, and that, whereas in the 1970s the full-income elasticity of demand for contemporaneity was higher among wives than among husbands, by the 1990s these elasticities were equal; and 4. using Dutch time-budget data for 1990 the author examines how households respond to the natural experiment of receiving an extra hour of time in a day (the day when winter time was reestablished). The evidence shows that the overwhelming majority of the extra hour was used for extra sleep, except among single men, who used much of the extra time to play sports and watch television.' (author's abstract)German title: Timing, Zusammengehoerigkeit und unverhoffte FreizeitAvailable from IAB-685 BK 824 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Exchange rate volatility effects on the German labour market A survey of recent results and extensions

'In this paper, a survey on theoretically expected and empirically proved impacts of exchange rate volatility is given. With regard to the West German unemployment, the effects of volatility are empirically analysed using three different volatility measures and four country groups. In autoregressive models, a significant disturbing impact of volatility can be found with annual data as well as with monthly data for the whole period. While this impact does not differ for the three volatility measures, it is, however, less strong when using the monthly data. Differentiating for different subperiods by use of the monthly data, the reported impact is stronger for relatively stable periods and country groups. When isolating the cyclical component of the unemployment rate, it can be demonstrated that the whole reported impact solely affects this component. In a dynamic Okun-type relation, an additional significant impact of volatility, however, cannot be proved for all subperiods.' (author's abstract)Die Autoren untersuchen mit Daten fuer den Zeitraum 1973-1997, wie sich Wechselkursschwankungen auf die Arbeitslosigkeit in (West-) Deutschland auswirkten. (IAB)German title: Auswirkungen der Wechselkursvolatilitaet auf den deutschen ArbeitsmarktAvailable from IAB-90-0BD0-205100 BH 320 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDiskussionsprotokollDEGerman

Important roles of the AKR1C2 and SRD5A1 enzymes in progesterone metabolism in endometrial cancer model cell lines.

Endometrial cancer is the most frequently diagnosed gynecological malignancy. It is associated with prolonged exposure to estrogens that is unopposed by progesterone, whereby enhanced metabolism of progesterone may decrease its protective effects, as it can deprive progesterone receptors of their active ligand. Furthermore, the 5&alpha;-pregnane metabolites formed can stimulate proliferation and may thus contribute to carcinogenesis. The aims of our study were to: 1) identify and quantify progesterone metabolites formed in the HEC-1A and Ishikawa model cell lines of endometrial cancer; and 2) pinpoint the enzymes involved in progesterone metabolism, and delineate their roles. Progesterone metabolism studies combined with liquid chromatography-tandem mass spectrometry enabled identification and quantification of the metabolites formed in these cells. Further quantitative PCR analysis and small-interfering-RNA-mediated gene silencing identified individual progesterone metabolizing enzymes and their relevant roles. In Ishikawa and HEC-1A cells, progesterone was metabolized mainly to 20&alpha;-hydroxy-pregn-4-ene-3-one, 20&alpha;-hydroxy-5&alpha;-pregnane-3-one, and 5&alpha;-pregnane-3&alpha;/&beta;,20&alpha;-diol. The major difference between these cell lines was rate of progesterone metabolism, which was faster in HEC-1A cells. In the Ishikawa and HEC-1A cells, expression of AKR1C2 was 110-fold and 6,800-fold greater, respectively, than expression of AKR1C1, which suggests that 20-ketosteroid reduction of 5&alpha;-pregnanes and 4-pregnenes is catalyzed mainly by AKR1C2. AKR1C1/AKR1C2 gene silencing showed decreased progesterone metabolism in both cell lines, thus further supporting the significant role of AKR1C2. SRD5A1 was also expressed in these cells, and its silencing confirmed that 5&alpha;-reduction is catalyzed by 5&alpha;-reductase type 1. Silencing of SRD5A1 also had the most pronounced effects, with decreased rate of progesterone metabolism, and consequently higher concentrations of unmetabolized progesterone. Our data confirm that in model cell lines of endometrial cancer, AKR1C2 and SRD5A1 have crucial roles in progesterone metabolism, and may represent novel targets for treatment

Combined liquid chromatography - tandem mass spectrometry analysis of progesterone metabolites.

Progesterone has a number of important functions throughout the human body. While the roles of progesterone are well known, the possible actions and implications of progesterone metabolites in different tissues remain to be determined. There is a growing body of evidence that these metabolites are not inactive, but can have significant biological effects, as anesthetics, anxiolytics and anticonvulsants. Furthermore, they can facilitate synthesis of myelin components in the peripheral nervous system, have effects on human pregnancy and onset of labour, and have a neuroprotective role. For a better understanding of the functions of progesterone metabolites, improved analytical methods are essential. We have developed a combined liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection and quantification of progesterone and 16 progesterone metabolites that has femtomolar sensitivity and good reproducibility in a single chromatographic run. MS/MS analyses were performed in positive mode and under constant electrospray ionization conditions. To increase the sensitivity, all of the transitions were recorded using the Scheduled MRM algorithm. This LC-MS/MS method requires small sample volumes and minimal sample preparation, and there is no need for derivatization. Here, we show the application of this method for evaluation of progesterone metabolism in the HES endometrial cell line. In HES cells, the metabolism of progesterone proceeds mainly to (20S)-20-hydroxy-pregn-4-ene-3-one, (20S)-20-hydroxy-5&alpha;-pregnane-3-one and (20S)-5&alpha;-pregnane-3&alpha;,20-diol. The investigation of possible biological effects of these metabolites on the endometrium is currently undergoing

Splitting the Recursive Least-Squares Algorithm

Exponentially weighted recursive least-squares (RLS) algorithms are commonly used for fast adaptation. In many cases the input signals are continuous-time. Either a fully analog implementation of the RLS algorithm is applied or the input data are sampled by analog-to-digital (AD) converters to be processed digitally. Although a digital realization is usually the preferred choice, it becomes unfeasible for high-frequency input signals since fast AD converters are needed. This paper proposes a hybrid analog/digital approach essentially allowing the AD conversion rate to be as low as the update-rate of the RLS algorithm. This is basically accomplished by sampling exponentially weighted correlation products instead of the input signals. Furthermore, we propose a mixed-signal filter exactly realizing the exponential weighting according to the cost function. Applying this approach to an interference cancelling problem demonstrates its performance and attractiveness regarding implementation