HPLC-MS/MS analyses show that the near-Starchless aps1 and pgm leaves accumulate wild type levels of ADPglucose: further evidence for the occurrence of important ADPglucose biosynthetic pathway(s) alternative to the pPGI-pPGM-AGP pathway

In leaves, it is widely assumed that starch is the end-product of a metabolic pathway exclusively taking place in the chloroplast that (a) involves plastidic phosphoglucomutase (pPGM), ADPglucose (ADPG) pyrophosphorylase (AGP) and starch synthase (SS), and (b) is linked to the Calvin-Benson cycle by means of the plastidic phosphoglucose isomerase (pPGI). This view also implies that AGP is the sole enzyme producing the starch precursor molecule, ADPG. However, mounting evidence has been compiled pointing to the occurrence of important sources, other than the pPGI-pPGM-AGP pathway, of ADPG. To further explore this possibility, in this work two independent laboratories have carried out HPLC-MS/MS analyses of ADPG content in leaves of the near-starchless pgm and aps1 mutants impaired in pPGM and AGP, respectively, and in leaves of double aps1/pgm mutants grown under two different culture conditions. We also measured the ADPG content in wild type (WT) and aps1 leaves expressing in the plastid two different ADPG cleaving enzymes, and in aps1 leaves expressing in the plastid GlgC, a bacterial AGP. Furthermore, we measured the ADPG content in ss3/ss4/aps1 mutants impaired in starch granule initiation and chloroplastic ADPG synthesis. We found that, irrespective of their starch contents, pgm and aps1 leaves, WT and aps1 leaves expressing in the plastid ADPG cleaving enzymes, and aps1 leaves expressing in the plastid GlgC accumulate WT ADPG content. In clear contrast, ss3/ss4/aps1 leaves accumulated ca. 300 fold-more ADPG than WT leaves. The overall data showed that, in Arabidopsis leaves, (a) there are important ADPG biosynthetic pathways, other than the pPGI-pPGM-AGP pathway, (b) pPGM and AGP are not major determinants of intracellular ADPG content, and (c) the contribution of the chloroplastic ADPG pool to the total ADPG pool is low.

Accessory gallbladder originating from the right hepatic duct

Major vascular injury during laparoscopic procedures is a rare but catastrophic complication. We report a pediatric case of aortic laceration during the setup phase of diagnostic laparoscopy in a 5-year-old girl with recurrent abdominal pain. The Veress needle inserted below the umbilicus confirmed the proper placement by use of a saline-filled syringe. The abdomen was insufflated without difficulty. The first trocar was inserted at the same point as Veress needle. The video laparoscope was introduced, and a small amount of blood was seen in the abdomen. We converted the procedure to laparotomy immediately. There was a large retroperitoneal hematoma. The vascular laceration was identified at the origin of the iliac arteries. It was sutured with prolene 5/0. The girl was discharged without further complication on the 10th postoperative day. The incidence of major vascular injuries is 0.03% to 0.07%. The vessels most frequently involved are the aorta, the iliac arteries, the mesenteric vessels, and the vena cava. More than 400 cases have been reported in the literature, but only four of these involve pediatric patients. In the vast majority of cases, the complication took place during the setup phase of laparoscopy (75%), and were related to the introduction of either the Veress needle (30%) or the first umbilical trocar (43%), although the rate is opposite this in some studies.

Clinical characteristics and prognostic influence of renal dysfunction in heart failure patients with preserved ejection fraction

BACKGROUND

Renal dysfunction is common in patients with heart failure (HF) and is associated with high mortality. This relationship is well established in HF and reduced ejection fraction (HFREF), however, it is not fully understood in HF and preserved ejection fraction (HFPEF). The aim of this study was to determine the impact of renal dysfunction on all-cause mortality in HFPEF patients and to evaluate the clinical characteristics of patients that deteriorate renal function in the first year of follow-up.

METHODS

We evaluated the patients with HFPEF included in the RICA registry. This is a multi-center and prospective cohort study that includes patients admitted for decompensated HF. Estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN) and plasma creatinine concentrations were used for renal function assessment at admission and after one year of follow up.

RESULTS

A total of 455 patients (mean age 78±8.1years; 62% women) were included, of whom 265 (58.2%) had eGFR<60mL/min/1.73m(2). After adjustment for covariates, only lower admission eGFR remained significantly predictive of all-cause mortality (HR 2.97; 95% CI 1.59-5.53). After one year of follow-up 16.6% of patients deteriorated at least 25% of eGFR. These patients were more likely to be diabetic (54.5% vs 42.6%; p=0.039) and had a higher rate of prescription of mineralcorticoid receptor antagonist (MRA) agents (47% vs 23.3%; p<0.001).

CONCLUSION

Renal dysfunction is frequently associated with HFPEF. eGFR below normal is strongly associated with mortality. Further decline of renal function is frequent especially among diabetic and patients treated with MRA agents.

Starch biosynthesis, its regulation and biotechnological approaches to improve crop yields

Structurally composed of the glucose homopolymers amylose and amylopectin, starch is the main storage carbohydrate in vascular plants, and is synthesized in the plastids of both photosynthetic and non-photosynthetic cells. Its abundance as a naturally occurring organic compound is surpassed only by cellulose, and represents both a cornerstone for human and animal nutrition and a feedstock for many non-food industrial applications including production of adhesives, biodegradable materials, and first-generation bioethanol. This review provides an update on the different proposed pathways of starch biosynthesis occurring in both autotrophic and heterotrophic organs, and provides emerging information about the networks regulating them and their interactions with the environment. Special emphasis is given to recent findings showing that volatile compounds emitted by microorganisms promote both growth and the accumulation of exceptionally high levels of starch in mono- and dicotyledonous plants. We also review how plant biotechnologists have attempted to use basic knowledge on starch metabolism for the rational design of genetic engineering traits aimed at increasing starch in annual crop species. Finally we present some potential biotechnological strategies for enhancing starch content.

Infliximab en pacientes con espondilitis anquilosante activa: experiencia en el Hospital Nacional Edgardo Rebagliati Martins

Infliximab es un medicamento efectivo en el tratamiento de pacientes con espondilitis anquilosante (EA) activa. Sin embargo, debido a su alto costo, su uso indiscriminado es prohibitivo. Objetivo: Evaluar si un régimen de inducción con infliximab es efectivo en pacientes con EA activa. Diseño: Sólo expuestos. Lugar: Servicio de Reumatología del Hospital Nacional Edgardo Rebagliati. Participantes: Pacientes con espondilitis anquilosante activa refractaria. Intervenciones: infliximab a las 0, 2 y 6 semanas. Un paciente recibió dosis de 3 mg/kg y los restantes 5 mg/kg de infliximab. Todos los pacientes continuaron recibiendo sulfasalazina. Principales medidas de resultados: Se determinó la proporción de pacientes que alcanzaron mejoría de acuerdo a los criterios ASAS 20, ASAS 40 y BASDAI 50, en la última evaluación (mediana de 55 semanas). Resultados: En la última evaluación, cinco pacientes (71,4%) presentaban respuesta ASAS 20 sostenida. Cuatro (57%) y tres (43%) de los pacientes alcanzaron BASDAI 50 y ASAS 40, respectivamente. Tres pacientes (43%) recayeron en un tiempo promedio de 26,6 semanas. No se observó efectos adversos serios. Conclusiones: La infusión de tres dosis de infliximab es efectiva para controlar la actividad de la enfermedad de los pacientes con EA refractaria a AINEs y en algunos pacientes controla la enfermedad por periodos prolongados de tiempo.

Enhancing sucrose synthase activity results in increased levels of starch and ADP-glucose in maize (Zea mays L.) seed endosperms

Sucrose synthase (SuSy) is a highly regulated cytosolic enzyme that catalyzes the conversion of sucrose and a nucleoside diphosphate into the corresponding nucleoside diphosphate glucose and fructose. In cereal endosperms, it is widely assumed that the stepwise reactions of SuSy, UDPglucose pyrophosphorylase and ADPglucose (ADPG) pyrophosphorylase (AGP) take place in the cytosol to convert sucrose into ADPG necessary for starch biosynthesis, although it has also been suggested that SuSy may participate in the direct conversion of sucrose into ADPG. In this study, the levels of the major primary carbon metabolites, and the activities of starch metabolism-related enzymes were assessed in endosperms of transgenic maize plants ectopically expressing StSUS4, which encodes a potato SuSy isoform. A total of 29 fertile lines transformed with StSUS4 were obtained, five of them containing a single copy of the transgene that was still functional after five generations. The number of seeds per ear of the five transgenic lines containing a single StSUS4 copy was comparable with that of wild-type (WT) control seeds. However, transgenic seeds accumulated 10-15% more starch at the mature stage, and contained a higher amylose/amylopectin balance than WT seeds. Endosperms of developing StSUS4-expressing seeds exhibited a significant increase in SuSy activity, and in starch and ADPG contents when compared with WT endosperms. No significant changes could be detected in the transgenic seeds in the content of soluble sugars, and in activities of starch metabolism-related enzymes when compared with WT seeds. A suggested metabolic model is presented wherein both AGP and SuSy are involved in the production of ADPG linked to starch biosynthesis in maize endosperm cells.

Impact of weight loss on mortality in chronic heart failure: findings from the RICA Registry

BACKGROUND

Obesity increases the risk of heart failure (HF), but a significant survival benefit in obese patients has been described once they have been diagnosed with HF. There is little information about the effects of weight loss among patients with HF. We aimed to assess the frequency of weight loss in patients with HF from the RICA Registry and whether weight loss is associated with mortality.

METHODS

We investigated weight changes in 731 patients with HF and analysed the effect of weight loss of 5% or more of their baseline bodyweight during follow-up.

RESULTS

419 (57.3%) patients lost weight during follow-up but only 152 (20.8%) lost at least 5% of the baseline bodyweight. We did not find significant differences in demographic, clinical, functional and analytical parameters between patients with and without weight loss or 5% or more of their bodyweight. We observed a significant improvement in the mean NYHA functional class value and a non-significant improvement in the LVEF in all patients. A significant decrease in the natriuretic peptide levels was only observed in the patients who lost weight. Survival rates at 1year follow-up for patients with and without weight loss or 5% or more were 75.7% (95% CI: 67.1-84.3%) and 77.1% (95% CI: 72.8-81.4%), respectively (p=0.92). Re-admission rates for patients with and without weight loss were 52.7% (95% CI: 42.9-62.43%) and 50.0% (95% CI: 45.3-54.7%), respectively (p=0.34).

CONCLUSIONS

Significant weight loss occurred in 20.8% of patients with HF. Weight loss was not associated with mortality or readmission.

Bacterial stimulation of the TLR-MyD88 pathway modulates the homeostatic expression of ileal Paneth cell α-defensins

Paneth cell α-defensins are antimicrobial peptides involved in the control of the intestinal microbiota and immunological homeostasis. In mice, they are encoded by multiple, highly homologous genes (Defa). The transcriptional activity of ileal Defa genes was studied in response to pharmacological and genetic perturbations of the intestinal environment of C57BL/6 mice. Defa gene transcription was sensitive to oral antibiotic administration suggesting that commensal microbes regulate Defa expression. Ileal microbiota analysis showed that decreased transcription of Defa genes correlated with depletion of Lactobacillus. Defa expression was partially restored in vivo by lactobacillus administration to antibiotic-treated mice. Defa transcripts were less abundant in ex vivo, microbiota-free intestinal explants but recovered after explant exposure to UV-killed bacteria, Toll-like receptor (TLR)-2 or TLR4 agonists. Genetic deficiency of several TLRs or MyD88 led to dramatic drops in Defa transcription in vivo. These results show that Paneth cell Defa genes are regulated by commensal bacteria through TLR-MyD88 signaling and provide a further understanding of the dysregulation of intestinal homeostasis that occurs as a result of imbalances in the populations of commensal bacteria.

No evidence for the occurrence of substrate inhibition of Arabidopsis thaliana sucrose synthase-1 (AtSUS1) by fructose and UDP-glucose

Sucrose synthase (SuSy) catalyzes the reversible conversion of sucrose and NDP into the corresponding nucleotide-sugars and fructose. The Arabidopsis genome possesses six SUS genes (AtSUS1-6) that code for proteins with SuSy activity. As a first step to investigate optimum fructose and UDP-glucose (UDPG) concentrations necessary to measure maximum sucrose-producing SuSy activity in crude extracts of Arabidopsis, in this work we performed kinetic analyses of recombinant AtSUS1 in two steps: (1) SuSy reaction at pH 7.5, and (2) chromatographic measurement of sucrose produced in step 1. These analyses revealed a typical Michaelis-Menten behavior with respect to both UDPG and fructose, with Km values of 50 μM and 25 mM, respectively. Unlike earlier studies showing the occurrence of substrate inhibition of UDP-producing AtSUS1 by fructose and UDP-glucose, these analyses also revealed no substrate inhibition of AtSUS1 at any UDPG and fructose concentration. By including 200 mM fructose and 1 mM UDPG in the SuSy reaction assay mixture, we found that sucrose-producing SuSy activity in leaves and stems of Arabidopsis were exceedingly higher than previously reported activities. Furthermore, we found that SuSy activities in organs of the sus1/sus2/sus3/sus4 mutant were ca. 80-90% of those found in WT plants.

Post-translational redox modification of ADP-glucose pyrophosphorylase in response to light is not a major determinant of fine regulation of transitory starch accumulation in Arabidopsis leaves

ADP-glucose pyrophosphorylase (AGP) is a heterotetrameric enzyme comprising two small and two large subunits that catalyze the production of ADP-glucose linked to starch biosynthesis. The current paradigm on leaf starch metabolism assumes that post-translational redox modification of AGP in response to light is a major determinant of fine regulation of transitory starch accumulation. According to this view, under oxidizing conditions occurring during the night the two AGP small subunits (APS1) are covalently linked via an intermolecular disulfide bridge that inactivates the protein, whereas under reducing conditions occurring during the day NADP-thioredoxin reductase C (NTRC)-dependent reductive monomerization of APS1 activates the enzyme. In this work we have analyzed changes in the redox status of APS1 during dark-light transition in leaves of plants cultured under different light intensities. Furthermore, we have carried out time-course analyses of starch content in ntrc mutants, and in aps1 mutants expressing the Escherichia coli redox-insensitive AGP (GlgC) in the chloroplast. We also characterized aps1 plants expressing a redox-insensitive, mutated APS1 (APS1mut) form in which the highly conserved Cys81 residue involved in the formation of the intermolecular disulfide bridge has been replaced by serine. We found that a very moderate, NTRC-dependent APS1 monomerization process in response to light occurred only when plants were cultured under photo-oxidative conditions. We also found that starch accumulation rates during the light in leaves of both ntrc mutants and GlgC-expressing aps1 mutants were similar to those of wild-type leaves. Furthermore, the pattern of starch accumulation during illumination in leaves of APS1mut-expressing aps1 mutants was similar to that of APS1-expressing aps1 mutants at any light intensity. The overall data demonstrate that post-translational redox modification of AGP in response to light is not a major determinant of fine regulation of transitory starch accumulation in Arabidopsis.

Sucrose synthase activity in the sus1/sus2/sus3/sus4 Arabidopsis mutant is sufficient to support normal cellulose and starch production

Sucrose synthase (SUS) catalyzes the reversible conversion of sucrose and a nucleoside diphosphate into the corresponding nucleoside diphosphate-glucose and fructose. In Arabidopsis, a multigene family encodes six SUS (SUS1-6) isoforms. The involvement of SUS in the synthesis of UDP-glucose and ADP-glucose linked to Arabidopsis cellulose and starch biosynthesis, respectively, has been questioned by Barratt et al. [(2009) Proc Natl Acad Sci USA 106:13124-13129], who showed that (i) SUS activity in wild type (WT) leaves is too low to account for normal rate of starch accumulation in Arabidopsis, and (ii) different organs of the sus1/sus2/sus3/sus4 SUS mutant impaired in SUS activity accumulate WT levels of ADP-glucose, UDP-glucose, cellulose and starch. However, these authors assayed SUS activity under unfavorable pH conditions for the reaction. By using favorable pH conditions for assaying SUS activity, in this work we show that SUS activity in the cleavage direction is sufficient to support normal rate of starch accumulation in WT leaves. We also demonstrate that sus1/sus2/sus3/sus4 leaves display WT SUS5 and SUS6 expression levels, whereas leaves of the sus5/sus6 mutant display WT SUS1-4 expression levels. Furthermore, we show that SUS activity in leaves and stems of the sus1/sus2/sus3/sus4 and sus5/sus6 plants is ∼85% of that of WT leaves, which can support normal cellulose and starch biosynthesis. The overall data disprove Barratt et al. (2009) claims, and are consistent with the possible involvement of SUS in cellulose and starch biosynthesis in Arabidopsis.

Specific delivery of AtBT1 to mitochondria complements the aberrant growth and sterility phenotype of homozygous Atbt1 Arabidopsis mutants

It has been shown that homozygous AtBT1::T-DNA Arabidopsis mutants display an aberrant growth and sterility phenotype, and that AtBT1 is a carrier that is exclusively localized to the inner plastidial envelope and is required for export of newly synthesized adenylates into the cytosol. However, a recent demonstration that AtBT1 is localized to both plastids and mitochondria suggested that plastidic AtBT1 is not necessary for normal growth and fertility of Arabidopsis. To test this hypothesis, we produced and characterized homozygous AtBT1::T-DNA mutants stably expressing either dually localized AtBT1 or AtBT1 specifically localized to the mitochondrial compartment. These analyses revealed that the aberrant growth and sterility phenotype of homozygous AtBT1::T-DNA mutants was complemented when expressing both the dual-targeted AtBT1 and AtBT1 specifically delivered to mitochondria. These data confirm that (i) plastidic AtBT1 is not strictly required for normal growth and fertility of the plant, and (ii) specific delivery of AtBT1 to mitochondria is enough to complement the aberrant growth and sterility phenotype of homozygous AtBT1::T-DNA mutants. Furthermore, data presented here question the idea that the requirement for AtBT1 is due to its involvement in transport of newly synthesized adenylates from the plastid to the cytosol, and suggest that the protein may play as yet unidentified functions in plastids and mitochondria.

Daily or monthly ibandronate prevents or restores deteriorations of bone mass, architecture, biomechanical properties and markers of bone turnover in androgen-deficient aged rats

AIM

The aim of this study was to investigate the effects of the bisphosphonate ibandronate (IBN) in a male osteoporosis animal model.

METHODS

Two studies were performed in 9-month-old orchidectomised (ORX) or sham-operated rats. In prevention study, subcutaneous IBN was administered daily (1 μg/kg) or monthly (28 μg/kg every 28 days) starting on day of surgery for 5 months. In treatment study, the same treatment started 6 months after ORX. After sacrifice, bone analyses by dual-energy X-ray absorptiometry, 3-dimensional micro-computed tomography, and 3-point bending were performed in femora or vertebrae. Serum tartrate-resistant acid phosphatase 5b (TRAP-5b) and aminoterminal propeptide of collagen I (PINP) were analysed for resorption and osteocalcin (BGP) for bone formation.

RESULTS

In both studies, ORX resulted in significant femoral and vertebral bone loss and microarchitectural deterioration after 5 months of ORX, and became more pronounced after 11 months. Biomechanical strength was also decreased. Serum levels for TRAP-5b and BGP increased while PINP levels were reduced or unchanged. Both daily and monthly IBN prevented or even restored ORX-induced changes in both studies, with the intermittent regimen showing a improvement in efficacy with respect to many of the biomechanical parameters.

Microbial volatile-induced accumulation of exceptionally high levels of starch in Arabidopsis leaves is a process involving NTRC and starch synthase classes III and IV

Microbial volatiles promote the accumulation of exceptionally high levels of starch in leaves. Time-course analyses of starch accumulation in Arabidopsis leaves exposed to fungal volatiles (FV) emitted by Alternaria alternata revealed that a microbial volatile-induced starch accumulation process (MIVOISAP) is due to stimulation of starch biosynthesis during illumination. The increase of starch content in illuminated leaves of FV-treated hy1/cry1, hy1/cry2, and hy1/cry1/cry2 Arabidopsis mutants was many-fold lower than that of wild-type (WT) leaves, indicating that MIVOISAP is subjected to photoreceptor-mediated control. This phenomenon was inhibited by cordycepin and accompanied by drastic changes in the Arabidopsis transcriptome. MIVOISAP was also accompanied by enhancement of the total 3-phosphoglycerate/Pi ratio, and a two- to threefold increase of the levels of the reduced form of ADP-glucose pyrophosphorylase. Using different Arabidopsis knockout mutants, we investigated the impact in MIVOISAP of downregulation of genes directly or indirectly related to starch metabolism. These analyses revealed that the magnitude of the FV-induced starch accumulation was low in mutants impaired in starch synthase (SS) classes III and IV and plastidial NADP-thioredoxin reductase C (NTRC). Thus, the overall data showed that Arabidopsis MIVOISAP involves a photocontrolled, transcriptionally and post-translationally regulated network wherein photoreceptor-, SSIII-, SSIV-, and NTRC-mediated changes in redox status of plastidial enzymes play important roles.

Arabidopsis thaliana mutants lacking ADP-glucose pyrophosphorylase accumulate starch and wild-type ADP-glucose content: further evidence for the occurrence of important sources, other than ADP-glucose pyrophosphorylase, of ADP-glucose linked to leaf starch biosynthesis

It is widely considered that ADP-glucose pyrophosphorylase (AGP) is the sole source of ADP-glucose linked to bacterial glycogen and plant starch biosynthesis. Genetic evidence that bacterial glycogen biosynthesis occurs solely by the AGP pathway has been obtained with glgC⁻ AGP mutants. However, recent studies have shown that (i) these mutants can accumulate high levels of ADP-glucose and glycogen, and (ii) there are sources other than GlgC, of ADP-glucose linked to glycogen biosynthesis. In Arabidopsis, evidence showing that starch biosynthesis occurs solely by the AGP pathway has been obtained with the starchless adg1-1 and aps1 AGP mutants. However, mounting evidence has been compiled previewing the occurrence of more than one important ADP-glucose source in plants. In attempting to solve this 20-year-old controversy, in this work we carried out a judicious characterization of both adg1-1 and aps1. Both mutants accumulated wild-type (WT) ADP-glucose and approximately 2% of WT starch, as further confirmed by confocal fluorescence microscopic observation of iodine-stained leaves and of leaves expressing granule-bound starch synthase fused with GFP. Introduction of the sex1 mutation affecting starch breakdown into adg1-1 and aps1 increased the starch content to 8-10% of the WT starch. Furthermore, aps1 leaves exposed to microbial volatiles for 10 h accumulated approximately 60% of the WT starch. aps1 plants expressing the bacterial ADP-glucose hydrolase EcASPP in the plastid accumulated normal ADP-glucose and reduced starch when compared with aps1 plants, whereas aps1 plants expressing EcASPP in the cytosol showed reduced ADP-glucose and starch. Moreover, aps1 plants expressing bacterial AGP in the plastid accumulated WT starch and ADP-glucose. The overall data show that (i) there occur important source(s), other than AGP, of ADP-glucose linked to starch biosynthesis, and (ii) AGP is a major determinant of starch accumulation but not of intracellular ADP-glucose content in Arabidopsis.

Colonic microbiota alters host susceptibility to infectious colitis by modulating inflammation, redox status, and ion transporter gene expression

Individuals vary in their resistance to enteric infections. The role of the intestinal microbiota in altering susceptibility to enteric infection is relatively unknown. Previous studies have identified that C3H/HeOuJ mice suffer 100% mortality during Citrobacter rodentium-induced colitis, whereas C57BL/6 mice recover from infection. The basis for their differences in susceptibility is unclear and has been mainly attributed to differences in host genetics. This study investigated the role of the intestinal microbiota in altering susceptibility to C. rodentium-induced colitis. When the feces of C57BL/6 mice were gavaged into antibiotic treated C3H/HeOuJ mice, the C57BL/6 microflora led to a complete reversal in mortality patterns where 100% of the C3H/HeOuJ mice survived infection. This protection corresponded with reduced colonic pathology and less systemic pathogen load and was associated with increased inflammatory and redox responses with reduced epithelial cell death. C3H/HeOuJ mice are normally susceptible to infection-induced dehydration due to defective expression of colonic ion transporters such as Dra, CA IV, and CA I; expression of these genes was normalized when C3H/HeOuJ mice were colonized with the C57BL/6 microflora. Together, these data reveal that the colonic microbiota play a critical role in protecting against intestinal infection by inducing proinflammatory and prooxidant responses that control pathogen load as well as ion transporter gene expression previously shown to prevent fatal dehydration. Protection of mice from lethal colitis was associated with higher levels of bacteria from Bacteroidetes. This study reveals that the microbiota is sufficient to overcome inherent genetic susceptibility patterns in C3H/HeOuJ mice that cause mortality during C. rodentium infection.

[Paradox of obesity in heart failure: results from the Spanish RICA Registry]

BACKGROUND AND OBJECTIVES

Obesity is a risk factor for heart failure (HF). Paradoxically, it has been described that body mass index (BMI) is inversely associated with mortality. The aim of this study was to analyse the relationship between BMI and mortality in a cohort of patients with HF.

PATIENTS AND METHODS

All patients included in the RICA Registry between March 2008 and September 2009 were analysed. RICA is a multicenter, prospective cohort study that includes patients admitted for decompensated HF in Spanish Internal Medicine Services. Patients were divided according to the WHO body weight categories.

RESULTS

712 patients were included; 54% were women and mean age was 77.3 years. Hypertensive cardiopathy was the most common etiology of HF with some differences according to BMI categories, being valvular disease more frequent among obese and overweight patients and ischemic HF among normal weight patients. Mean left ventricle ejection fraction was 50.2% and it was higher among higher BMI categories. Natriuretic peptide levels were significantly lower among higher BMI categories (P<.05). Overall mortality after one-year of follow-up was 13.9% and it was significantly lower among higher BMI categories: normal BMI 20.4%, overweight 14.7% and obesity 8.5% (P<.01). In the multivariate analysis, overweight was significantly and independently associated with an increased mortality risk in comparison with obesity: RR 3.05 (IC95% 1.24-7.54).

CONCLUSIONS

An increase in BMI was associated with lower levels of natriuretic peptides and lower mortality.

Prevalence and clinical profile and management of peripheral arterial disease in elderly patients with diabetes

INTRODUCTION

Peripheral arterial disease (PAD) increases with age and diabetes. The aim of this study was to assess the prevalence of PAD in an elderly population with diabetes.

METHODS

This multicenter and cross-sectional study included patients >70 years, with an established diagnosis of diabetes. PAD was defined as those patients with a history of revascularization or amputation due to ischemia, or a pathological ankle-brachial index (ABI). Adequate blood pressure (BP), LDL cholesterol and HbA1c control were considered as <130/80 mm Hg, <100 mg⁄dL and <7.0%, respectively.

RESULTS

A total of 1462 patients were included. The most frequent cardiovascular risk factor and cardiovascular disease were hypertension (80.37%) and PAD (60.60% overall; 83.2% of those assisted by vascular surgeons vs 31.9% of those attended by other medical specialists; p<0.001), respectively. However, when ABI was measured, 70.99% of the study population had PAD (80.2% of those assisted by vascular surgeons vs 59.6% of those attended by other medical specialists; p<0.001). The predictors for a pathological ABI included male gender, smoking, dyslipidemia, family history of premature cardiovascular disease, sedentary lifestyle, diabetic-related complications, heart and cerebrovascular diseases. Although risk factors control was very poor, it was even lower in patients with PAD.

CONCLUSIONS

The prevalence of PAD is high in diabetic elderly patients. The concomitance with other risk factors and cardiovascular diseases was very high. The ABI allowed increasing the diagnosis of PAD.

Dual targeting to mitochondria and plastids of AtBT1 and ZmBT1, two members of the mitochondrial carrier family

Zea mays and Arabidopsis thaliana Brittle 1 (ZmBT1 and AtBT1, respectively) are members of the mitochondrial carrier family. Although they are presumed to be exclusively localized in the envelope membranes of plastids, confocal fluorescence microscopy analyses of potato, Arabidopsis and maize plants stably expressing green fluorescent protein (GFP) fusions of ZmBT1 and AtBT1 revealed that the two proteins have dual localization to plastids and mitochondria. The patterns of GFP fluorescence distribution observed in plants stably expressing GFP fusions of ZmBT1 and AtBT1 N-terminal extensions were fully congruent with that of plants expressing a plastidial marker fused to GFP. Furthermore, the patterns of GFP fluorescence distribution and motility observed in plants expressing the mature proteins fused to GFP were identical to those observed in plants expressing a mitochondrial marker fused to GFP. Electron microscopic immunocytochemical analyses of maize endosperms using anti-ZmBT1 antibodies further confirmed that ZmBT1 occurs in both plastids and mitochondria. The overall data showed that (i) ZmBT1 and AtBT1 are dually targeted to mitochondria and plastids; (ii) AtBT1 and ZmBT1 N-terminal extensions comprise targeting sequences exclusively recognized by the plastidial compartment; and (iii) targeting sequences to mitochondria are localized within the mature part of the BT1 proteins.

Regulation of glycogen metabolism in yeast and bacteria

Microorganisms have the capacity to utilize a variety of nutrients and adapt to continuously changing environmental conditions. Many microorganisms, including yeast and bacteria, accumulate carbon and energy reserves to cope with the starvation conditions temporarily present in the environment. Glycogen biosynthesis is a main strategy for such metabolic storage, and a variety of sensing and signaling mechanisms have evolved in evolutionarily distant species to ensure the production of this homopolysaccharide. At the most fundamental level, the processes of glycogen synthesis and degradation in yeast and bacteria share certain broad similarities. However, the regulation of these processes is sometimes quite distinct, indicating that they have evolved separately to respond optimally to the habitat conditions of each species. This review aims to highlight the mechanisms, both at the transcriptional and at the post-transcriptional level, that regulate glycogen metabolism in yeast and bacteria, focusing on selected areas where the greatest increase in knowledge has occurred during the last few years. In the yeast system, we focus particularly on the various signaling pathways that control the activity of the enzymes of glycogen storage. We also discuss our recent understanding of the important role played by the vacuole in glycogen metabolism. In the case of bacterial glycogen, special emphasis is placed on aspects related to the genetic regulation of glycogen metabolism and its connection with other biological processes.