Cardiovascular risk profile and frailty in a population-based study of older British men.

BACKGROUND: Frailty in older age is known to be associated with cardiovascular disease (CVD) risk. However, the extent to which frailty is associated with the CVD risk profile has been little studied. Our aim was to examine the associations of a range of cardiovascular risk factors with frailty and to assess whether these are independent of established CVD. METHODS: Cross-sectional study of a socially representative sample of 1622 surviving men aged 71-92 examined in 2010-2012 across 24 British towns, from a prospective study initiated in 1978-1980. Frailty was defined using the Fried phenotype, including weight loss, grip strength, exhaustion, slowness and low physical activity. RESULTS: Among 1622 men, 303 (19%) were frail and 876 (54%) were pre-frail. Compared with non-frail, those with frailty had a higher odds of obesity (OR 2.03, 95% CI 1.38 to 2.99), high waist circumference (OR 2.30, 95% CI 1.67 to 3.17), low high-density lipoprotein-cholesterol (HDL-C) (OR 2.28, 95% CI 1.47 to 3.54) and hypertension (OR 1.79, 95% CI 1.27 to 2.54). Prevalence of these factors was also higher in those with frailty (prevalence in frail vs non-frail groups was 46% vs 31% for high waist circumference, 20% vs 11% for low HDL and 78% vs 65% for hypertension). Frail individuals had a worse cardiovascular risk profile with an increased risk of high heart rate, poor lung function (forced expiratory volume in 1 s (FEV1)), raised white cell count (WCC), poor renal function (low estimated glomerular filtration rate), low alanine transaminase and low serum sodium. Some risk factors (HDL-C, hypertension, WCC, FEV1, renal function and albumin) were also associated with being pre-frail. These associations remained when men with prevalent CVD were excluded. CONCLUSIONS: Frailty was associated with increased risk of a range of cardiovascular factors (including obesity, HDL-C, hypertension, heart rate, lung function, renal function) in older people; these associations were independent of established CVD

Characterisation of a putative glutamate 5‐kinase from <i>Leishmania donovani</i>

Previous metabolic studies have demonstrated that leishmania parasites are able to synthesise proline from glutamic acid and threonine from aspartic acid. The first committed step in both biosynthetic pathways involves an amino acid kinase, either a glutamate 5‐kinase (G5K; EC2.7.2.11) or an aspartokinase (EC2.7.2.4). Bioinformatic analysis of multiple leishmania genomes identifies a single amino acid‐kinase gene (LdBPK 262740.1) variously annotated as either a putative glutamate or aspartate kinase. To establish the catalytic function of this Leishmania donovani gene product, we have determined the physical and kinetic properties of the recombinant enzyme purified from Escherichia coli. The findings indicate that the enzyme is a bona fide G5K with no activity as an aspartokinase. Tetrameric G5K displays kinetic behaviour similar to its bacterial orthologues and is allosterically regulated by proline, the end product of the pathway. The structure‐activity relationships of proline analogues as inhibitors are broadly similar to the bacterial enzyme. However, unlike G5K from E. coli, leishmania G5K lacks a C‐terminal PUA (pseudouridine synthase and archaeosine transglycosylase) domain and does not undergo higher oligomerisation in the presence of proline. Gene replacement studies are suggestive, but not conclusive that G5K is essential

FK 506 ameliorates the hepatic injury associated with ischemia and reperfusion in rats

The effect of FK 506 on regeneration of the liver was studied in rats after a two‐thirds partial hepatectomy after 60 min of ischemia of the unresected liver. The animals were divided into three distinct groups of 10 rats each. Group 1 (controls) received 0.5 ml saline solution intravenously 30 min after the induction of ischemia. Groups 2 and 3 were injected with FK 506 (0.3 mg/kg) intravenously 30 min after and 24 min before the induction of hepatic ischemia, respectively. The hepatic content of ATP and serum levels of ALT and lactate dehydrogenase were determined on each animal. In addition, the histological appearance and mitotic activity of the remnant liver was determined at regular 24‐hr intervals after hepatic ischemia. All 10 control animals died within 72 hr. Treatment with FK 506 resulted in improved survival in groups 2 and 3 (30% and 80%, respectively). The improved survival seen in the FK 506–treated animals was reflected by a restoration of hepatic ATP content, a reduction in the serum levels of ALT and lactate dehydrogenase, an amelioration of hepatic necrosis and neutrophilic infiltration and an increase in the mitotic activity of the liver. These results suggest that FK 506 ameliorates the hepatic injury associated with ischemia/reperfusion and has a potent stimulatory effect on liver cell regeneration that may make it valuable as a hepatoprotective agent when administered to organ donors before graft harvesting. (HEPATOLOGY 1991;13:947–951.) Copyright © 1991 American Association for the Study of Liver Disease

Latent acetylcholinesterase in secretory vesicles isolated from adrenal medulla

A new procedure is described for the preparation of highly purified and stable secretory vesicles from adrenal medulla. Two forms of acetylcholinesterase, a membrane bound form as well as a soluble form, were found within these vesicles. The secretory vesicles, isolated by differential centrifugation, were further purified on a continuous isotonic Percoll™ gradient. In this way, secretory vesicles were separated from mitochondrial, microsomal and cell membrane contamination. The secretory vesicles recovered from the gradient contained an average of 2.26 μmol adrenalin/mg protein. On incubation for 30 min at 37°C in media differing in ionic strength, pH, Mg2+ and Ca2+ concentration, the vesicles released less than 20% of total adrenalin. Acetylcholinesterase could hardly be detected in the secretory vesicle fraction when assayed in isotonic media. However, in hypotonic media (<400 mosmol/kg) or in Triton X-100 (0.2% final concentration) acetylcholinesterase activity was markedly higher. During hypotonic treatment or when secretory vesicles were specifically lyzed with 2 mM Mg2+ and 2 mM ATP, adrenalin as well as part of acetylcholinesterase was released from the vesicular content. On polyacrylamide gel electrophoresis this soluble enzyme exhibited the same electrophoretic mobility as the enzyme released into the perfusate from adrenal glands upon stimulation. In addition to the soluble enzyme a membrane bound form of acetylcholinesterase exists within secretory vesicles, which sediments with the secretory vesicle membranes and exhibits a different electrophoretic mobility compared to the soluble enzyme. It is concluded, that the soluble enzyme found within isolated secretory vesicles is secreted via exocytosis, whilst the membrane-bound form is transported to the cell membrane during this process, contributing to the biogenesis of the cell membrane

Assembly of microtubules with ATP: evidence that only a fraction of the protein is assembly-competent

AbstractChick brain microtubule protein can be assembled in vitro with ATP, although the extent of assembly is less than that with GTP. The ATP-induced assembly is not the result of generation of GTP by the co-purifying nucleoside diphosphate kinase. Neither an observed increase in the critical concentration nor the phosphorylation of MAP2 can account for the decreased extent of assembly. However, whereas microtubules are formed with both ATP and GTP, incubation with ATP yields additional filaments and polymorphic aggregates. The results demonstrate that of the total protein which can be assembled into microtubules by GTP, about 25–35% is assembled into other structural forms in the presence of ATP

Non-invasive assessment of liver disease in rats using multiparametric magnetic resonance imaging: a feasibility study

Non-invasive quantitation of liver disease using multiparametric magnetic resonance imaging (MRI) could refine clinical care pathways, trial design and preclinical drug development. The aim of this study was to evaluate the use of multiparametric MRI in experimental models of liver disease. Liver injury was induced in rats using 4 or 12 weeks of carbon tetrachloride (CCl4) intoxication and 4 or 8 weeks on a methionine and choline deficient (MCD) diet. Liver MRI was performed using a 7.0 Tesla small animal scanner at baseline and specified timepoints after liver injury. Multiparametric liver MRI parameters [T1 mapping, T2* mapping and proton density fat fraction (PDFF)] were correlated with gold standard histopathological measures. Mean hepatic T1 increased significantly in rats treated with CCl4 for 12 weeks compared to controls [1122±78 ms versus 959±114 ms; d=162.7, 95% CI (11.92, 313.4), P=0.038] and correlated strongly with histological collagen content (rs=0.717, P=0.037). In MCD diet-treated rats, hepatic PDFF correlated strongly with histological fat content (rs=0.819, P<0.0001), steatosis grade (rs=0.850, P<0.0001) and steatohepatitis score (rs=0.818, P<0.0001). Although there was minimal histological iron, progressive fat accumulation in MCD diet-treated livers significantly shortened T2*. In preclinical models, quantitative MRI markers correlated with histopathological assessments, especially for fatty liver disease. Validation in longitudinal studies is required. This article has an associated First Person interview with the first author of the paper

Peroxisome proliferator-activated receptor γ agonism attenuates endotoxaemia-induced muscle protein loss and lactate accumulation in rats

The peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone (Rosi) appears to provide protection against organ dysfunction during endotoxaemia. We examined the potential benefits of Rosi on skeletal muscle protein maintenance and carbohydrate metabolism during lipopolysaccharide (LPS)-induced endotoxaemia. Sprague-Dawley rats were fed either standard chow (control) or standard chow containing Rosi (8.5±0.1 mg.kg-1.day-1) for two weeks before and during 24 h continuous intravenous infusion of LPS (15 μg.kg-1.h-1) or saline. Rosi blunted LPS-induced increases in muscle tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) mRNA by 70% (P<0.05) and 64% (P<0.01), respectively. Furthermore, Rosi suppressed the LPS-induced reduction in phosphorylated AKT and phosphorylated Forkhead box O (FOXO) 1 protein, as well as the upregulation of muscle RING finger 1 (MuRF1; P<0.01) mRNA, and the LPS-induced increase in 20S proteasome activity (P<0.05). Accordingly, LPS reduced the muscle protein:DNA ratio (~30%, P<0.001), which Rosi offset. Increased muscle pyruvate dehydrogenase kinase 4 (PDK4) mRNA (P<0.001) and muscle lactate accumulation (P<0.001) during endotoxaemia were suppressed by Rosi. Thus, pre-treatment with Rosi reduced muscle cytokine accumulation and blunted muscle protein loss and lactate accumulation during endotoxaemia, and at least in part by reducing activation of molecular events known to increase muscle protein breakdown and mitochondrial pyruvate use

Alanine aminotransferase and the 6-year risk of the metabolic syndrome in Caucasian men and women: the Hoorn Study

Aims: To study the association between alanine aminotransferase (ALT) and the 6-year risk of the metabolic syndrome in a population-based study in Caucasian men and women. Methods: The association of ALT with the 6-year risk of the metabolic syndrome in 1097 subjects, aged 50-75 years, was assessed in the Hoorn Study with logistic regression analysis. Subjects with the metabolic syndrome at baseline, defined according to the Adult Treatment Panel III of the National Cholesterol Education Program, were excluded. Results: After 6.4 (range 4.4-8.1) years follow-up, 226 subjects (20.6%) had developed the metabolic syndrome. The odds ratio (95% confidence interval) for developing the metabolic syndrome, adjusted for age, sex, alcohol intake and follow-up duration was 2.25 (1.50-3.37) for subjects in the upper tertile compared with those in the lower tertile of ALT. This association persisted after additional adjustment for all the baseline metabolic syndrome features [1.62 (1.02-2.58)]. Among the individual components of the metabolic syndrome, ALT was significantly associated only with fasting plasma glucose at follow-up. Conclusions: These data suggest that ALT is associated with risk of the metabolic syndrome in a general population of middle-aged Caucasian men and women, further strengthening the role of ALT as an indicator for future metabolic derangement. These findings warrant further studies to elucidate the role of non-adipose tissue fat accumulation in the pathogenesis of complications related to the metabolic syndrome