Quality analysis and categorisation of public space

Public spaces are considered areas that promote users' physical and mental health. The role of these people in public spaces makes it necessary to evaluate such areas. In this study, 12 urban parks on the island of Tenerife were evaluated, combining the assessment of a trained observer and the perception of users, to analyse and categorise the environmental quality of the parks. The findings of this study conclude that users are good evaluators of public spaces; that the Public Space Characteristics Observation Questionnaire (PSCOQ) tool allows the classification of public spaces and that physical order is capable of predicting the environmental quality and the restorative capacity of spaces, as perceived by users. The PSCOQ observation tool makes it possible to detect the strengths and weaknesses of public spaces so they can be improved and adapted to the needs of users.

Right heart dysfunction and readmission risk across left ventricular ejection fraction status in patients with acute heart failure

Background

Right heart dysfunction (RHD) parameters, such as right ventricular to pulmonary artery uncoupling or significant tricuspid regurgitation (TR) are increasingly important in heart failure (HF), especially in patients with preserved ejection fraction. In this study, we aimed to evaluate the association of advanced RHD with the risk of recurrent admissions across the spectrum of left ventricular ejection fraction (LVEF).

Methods

We included 3,383 consecutive patients discharged for acute HF (AHF). Of them, in 1,435 (42.4%) pulmonary artery systolic pressure (PASP) could not be accurately measured, leaving a final sample size of 1,948 patients. Advanced RHD was defined as the combination of a ratio of tricuspid annular plane systolic excursion (TAPSE)/PASP<0.36 and a significant functional TR (n=196, 10.2%). Negative binomial regression analyses were used to evaluate the risk of recurrent admissions.

Results

At a median follow up of 2.2 years (IQR=0.63–4.71), 3,782 readmissions were registered in 1,296 patients (66.5%). Patients with advanced RHD showed higher rates of readmissions, but only if LVEF≥40% (p<0.001). In multivariable analyses, this differential association persisted for CV and HF recurrent admissions (p-value for interaction=0.016 and p=0.020; respectively). Advanced RHD was independently associated with the risk of recurrent CV and HF admissions if HF with LVEF≥40% (IRR: 1.99, 95% CI: 1.47–2.69, p<0.001; and IRR: 2.02, 95% CI: 1.45–2.81, p<0.001; respectively). In contrast, it was not associated with readmission risks if LVEF<40%.

Conclusion

Following an admission for AHF, advanced RHD was strongly associated with a higher risk of recurrent CV and HF admissions, but only in patients with LVEF≥40%.

Funding Acknowledgement

Type of funding sources: None.

Sex-related differences in mortality following an admission for acute heart failure across left ventricular ejection fraction spectrum

Background

Prognosis in heart failure (HF) may differ between women and men. However, data is conflicting and sex-related differences in prognosis may be determined by left ventricular ejection fraction (LVEF) status. We sought to evaluate the prognostic differences between women and men with HF following an admission for acute HF (AHF).

Methods

We included 4,812 patients consecutively admitted for AHF in a multicenter registry from 3 hospitals in Valencia (Spain). Study endpoints were all-cause, cardiovascular (CV), and HF-related mortality at 6-months follow-up. Multivariable Cox regression models were fitted to investigate sex-related differences across LVEF status.

Results

2,243 (46.6%) patients were women and 2,569 (53.4%) were men. 2,608 (54.2%) patients had HF with preserved ejection fraction. At 6-months follow-up, 645 patients died (13.4%), being 544 (11.3%) and 416 (8.6%) CV and HF-related deaths, respectively. LVEF was not independently associated to mortality risk (HR=1.02; 95% CI 0.99–1.05; p=0.135). After multivariate adjustment, we found no sex-related differences in all-cause mortality (p-value for interaction=0.168). However, a significant interaction between sex and the risk of CV and HF mortality was found across LVEF status (p-value for interaction= 0.030 and 0.007; respectively). Compared to men, women had a significant lower risk of CV-mortality and HF-mortality at LVEF<25% and <42%, respectively. On the contrary, women showed a higher risk of HF-mortality at the upper extreme of LVEF (>75%) (Figure, panel A and B).

Conclusions

Following an admission for AHF, no sex-related differences were found in the risk of all-cause mortality. However, compared to men, women showed a lower risk of CV and HF-mortality at the lower extreme of LVEF. On the contrary, they showed a higher risk of HF-death at the upper extreme.

Funding Acknowledgement

Type of funding sources: None.

[Pack-years threshold and HAS self-questionnaire for COPD early diagnosis]

INTRODUCTION

The Haute Autorité de santé (HAS) in France offers a patient self-questionnaire to optimize targeted chronic obstructive pulmonary disease (COPD) screening among at-risk patients in primary care. It includes smoking but does not have a threshold for pack-years (PY) smoked. The objective of this study was to compare the positive predictive values (PPV) of the HAS self-questionnaire alone and with the addition of a PY threshold.

METHODS

This was a prospective pilot study conducted in a multi-professional health centre. Identification among smoking or former smoking patients without a COPD diagnosis of subjects with a positive HAS self-questionnaire, a positive PY threshold, or both. We performed spirometry after bronchodilatation.

RESULTS

Thirty-five people were included in the study. All 35 had a positive PY threshold. The HAS questionnaire was positive for 22 of them (62.9%). Spirometry diagnosed 18 participants with COPD (51%). The PPV for the HAS questionnaire was 0.41 and the PPV for the HAS+PY questionnaire was 0.51. There was no statistically significant difference between these two PPVs (P=0.3692).

CONCLUSIONS

The addition of a PY threshold to the HAS self-questionnaire may allow better targeting of the population at risk of developing COPD.

Longitudinal measurement invariance of the Satisfaction With Life Scale in adolescence

PURPOSE

The main purpose of this research was to examine the longitudinal measurement invariance of the Satisfaction With Life Scale (SWLS) in adolescence.

METHOD

The sample was composed by 484 adolescents from Spain, 46.7% were males. All participants belonged to six academic levels from Grade 7 to Grade 12, and answered the questionnaires at two different times: at the beginning (M_age1 = 14.95, SD₁ = 1.81) and at the end of the school year (M_age2 = 15.61, SD₂ = 1.81). The reliability of the scale was obtained through Cronbach's alpha, Guttman lambda, and MacDonald's Omega total. The multiple group confirmatory factor analysis (MGCFA) was used to examine the fit of the unifactorial model to data and to test the measurement of longitudinal invariance of the scale across two time points (at the beginning T1, and the end T2, of the academic year), and the time points and groups (gender and age).

RESULTS

The values of the single-factor SWLS structure were T1 (CFI₁ = 1.000, TLI₁ = .997, RMSEA₁ = .080, and SRMR₁ = .028), and T2 (CFI₂ = .997, TLI₂ = .995, RMSEA₂ = .032, and SRMR₂ = .034). On the other hand, values of the reliability and composite reliability when analyzing both time points together as well as separately were as follows: Cronbach's alpha = .86, Guttman's lambda = .84, McDonald's Omega total = .89. Results confirmed the longitudinal invariance of SWLS. The differences in gender and age were not significant and the small differences across time points showed that the means of the latent factor remained the same over time in both variables.

CONCLUSION

The present study confirmed the single-factor structure of the SWLS in Spanish adolescents, as well as a good reliability and composite reliability. The full longitudinal measurement invariance was also found and there were negligible differences across time points considering gender and age. If these findings are further replicated, the scale could be used to compare the life satisfaction across two time points considering different age and gender groups.

Changes in apoplastic peroxidase activity and cell wall composition are associated with cold-induced morpho-anatomical plasticity of wheat leaves

Temperate grasses, such as wheat, become compact plants with small thick leaves after exposure to low temperature. These responses are associated with cold hardiness, but their underlying mechanisms remain largely unknown. Here we analyse the effects of low temperature on leaf morpho-anatomical structure, cell wall composition and activity of extracellular peroxidases, which play key roles in cell elongation and cell wall thickening, in two wheat cultivars with contrasting cold-hardening ability. A combined microscopy and biochemical approach was applied to study actively growing leaves of winter (ProINTA-Pincén) and spring (Buck-Patacón) wheat developed under constant warm (25 °C) or cool (5 °C) temperature. Cold-grown plants had shorter leaves but longer inter-stomatal epidermal cells than warm-grown plants. They had thicker walls in metaxylem vessels and mestome sheath cells, paralleled with accumulation of wall components, predominantly hemicellulose. These effects were more pronounced in the winter cultivar (Pincén). Cold also induced a sharp decrease in apoplastic peroxidase activity within the leaf elongating zone of Pincén, and a three-fold increase in the distal mature zone of the leaf. This was consistent with the enhanced cell length and thicker cell walls in this cultivar at 5 °C. The different response to low temperature of apoplastic peroxidase activity and hemicellulose between leaf zones and cultivar types suggests they might play a central role in the development of cold-induced compact morphology and cold hardening. New insights are presented on the potential temperature-driven role of peroxidases and hemicellulose in cell wall dynamics of grasses.

Vena Cava Filters: A Synopsis of Complications and Related Topics

Deep venous thrombosis and pulmonary embolism constitute common preventable causes of morbidity and mortality. The incidence of venous thromboembolism (VTE) continues to increase. Standard anticoagulation therapy may reduce the risk of fatal PE by 75% and that of recurrent VTE by over 90%. For patients who are not candidates for anticoagulation, a vena cava filter (VCF) may be beneficial. Despite a good overall safety record, significant complications related to VCF are occasionally seen. This review discusses both procedural and non-procedural complications associated with VCF placement and use. We will also discuss VCF use in the settings of pregnancy, malignancy, and the clinical need for more than one filter.

Alexithymia, recognition of facial emotion and inference in patients with Eating Disorders (ED) or Substance Abuse Disorders (SAD)

Alexythimia is a psychological construct characterized by difficulty describing emotions and distinguishing them from somatic components of the emotional activation. Patients with eating disorders (ED) or substance use disorders (SAD) commonly present also impairment of recognition of facial expressions and deficits in social inference. Patients with ED and SAD may present impulsiveness, difficulty in emotion-focused coping skills, and search for a concrete relief from psychological suffering. The purpose of study is to compare the ED, SAD and healthy controls (HC), in several variables, including Alexythimia, empathy, and ability to recognize emotions, social inference. Thirty-two patients with ED, 27 patients with SAD and 31 HC were recruited between September 2016 and April 2016 at the psychiatric ward of Novara Hospital, nursing home of Nebbiuno and the nursing home of Viverone. We administrated to patients the same battery of tests, composed by Toronto Alexithymia Scale-20 (TAS-20), Facial Emotion Identification Test (FEIT), the awareness of Social Inference Test (TASIT), temperament and Character Inventory (TCI), Interpersonal Reactivity Index (IRI), Symptoms Checklist-90 (SCL-90). The two clinical groups showed differences in TAS, FEIT and TASIT, highlighting Alexythimic tracts, difficulty in recognizing emotions and deficit of social inference, compared to HCs. The TCI and SCL-90 have also highlighted the common psychopathological characteristics and temperamental in patients with ED and SAD. Alexythimia is particularly represented in patients with ED and SAD, and could represent a maintenance factor, together with deficits in emotions recognition and social inference. The similarities between ED and TD seem to suggest the possibility of shared core features.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Synthetic peptides for the immunodiagnosis of hepatitis A virus infection

VP1, VP2 and VP3 molecules of hepatitis A virus are exposed capsid proteins that have shown to be antigenic and are used for diagnosis in recombinant-antigen commercial kits. In this study, we developed a sequence analysis in order to predict diagnostic peptide epitopes, followed by their spot synthesis on functionalized cellulose paper (Pepscan). This paper with synthetic peptides was tested against a sera pool of hepatitis A patients. Two peptide sequences, that have shown an antigenic recognition, were selected for greater scale synthesis on resin. A dimeric form of one of these peptides (IMT-1996), located in the C-Terminus region of protein VP1, was antigenic with a recognition frequency of 87-100% of anti-IgG antibodies and 100% of anti-IgM antibodies employing the immunological assays MABA and ELISA. We propose peptide IMT-1996, with less than twenty residues, as a cheaper alternative for prevalence studies and diagnosis of hepatitis A infection.

Long-term thermal stabilities of ammonium ionic liquids designed as potential absorbents of ammonia

Searching for potential absorbents in working pairs with NH₃, a series of new ammonium ionic liquids related to choline, were designed and synthesized. Their thermal stabilities in both non-isothermal and isothermal conditions were studied.

Skeletal muscle myogenesis is regulated by G protein-coupled receptor kinase 2

G protein-coupled receptor kinase 2 (GRK2) is an important serine/threonine-kinase regulating different membrane receptors and intracellular proteins. Attenuation of Drosophila Gprk2 in embryos or adult flies induced a defective differentiation of somatic muscles, loss of fibers, and a flightless phenotype. In vertebrates, GRK2 hemizygous mice contained less but more hypertrophied skeletal muscle fibers than wild-type littermates. In C2C12 myoblasts, overexpression of a GRK2 kinase-deficient mutant (K220R) caused precocious differentiation of cells into immature myotubes, which were wider in size and contained more fused nuclei, while GRK2 overexpression blunted differentiation. Moreover, p38MAPK and Akt pathways were activated at an earlier stage and to a greater extent in K220R-expressing cells or upon kinase downregulation, while the activation of both kinases was impaired in GRK2-overexpressing cells. The impaired differentiation and fewer fusion events promoted by enhanced GRK2 levels were recapitulated by a p38MAPK mutant, which was able to mimic the inhibitory phosphorylation of p38MAPK by GRK2, whereas the blunted differentiation observed in GRK2-expressing clones was rescued in the presence of a constitutively active upstream stimulator of the p38MAPK pathway. These results suggest that balanced GRK2 function is necessary for a timely and complete myogenic process.

TWEAK prevents TNF-α-induced insulin resistance through PP2A activation in human adipocytes

Visceral fat is strongly associated with insulin resistance. Obesity-associated adipose tissue inflammation and inflammatory cytokine production are considered key mediators of insulin signaling inhibition. TWEAK is a relatively new member of the TNF cytokine superfamily, which can exist as full length membrane-associated (mTWEAK) and soluble (sTWEAK) isoforms. Although TWEAK has been shown to have important functions in chronic inflammatory diseases its physiological role in adipose tissue remains unresolved. In this study, we explore the molecular mechanisms involved in the modulation of TNF-α-induced effects on insulin sensitivity by sTWEAK in a human visceral adipose cell line and also in primary human adipocytes obtained from visceral fat depots. Our data reveal that sTWEAK ameliorates TNF-α-induced insulin resistance on glucose uptake, GLUT4 translocation and insulin signaling without affecting other metabolic effects of TNF-α such as lipolysis or apoptotis. Co-immunoprecipitation experiments in adipose cells revealed that pretreatment with sTWEAK specifically inhibits TRAF2 association with TNFR1, but not with TNFR2, which mediates insulin resistance. However, sTWEAK does not affect other downstream molecules activated by TNF-α, such as TAK1. Rather, sTWEAK abolishes the stimulatory effect of TNF-α on JNK1/2, which is directly involved in the development of insulin resistance. This is associated with an increase in PP2A activity upon sTWEAK treatment. Silencing of the PP2A catalytic subunit gene overcomes the dephosphorylation effect of sTWEAK on JNK1/2, pointing to PP2A as a relevant mediator of sTWEAK-induced JNK inactivation. Overall, our data reveal a protective role of TWEAK in glucose homeostasis and identify PP2A as a new driver in the modulation of TNF-α signaling by sTWEAK.

Metabolic rescue of obese adipose-derived stem cells by Lin28/Let7 pathway

Adipose-derived stem cells (ASCs) are promising candidates for autologous cell-based regeneration therapies by virtue of their multilineage differentiation potential and immunogenicity; however, relatively little is known about their role in adipose tissue physiology and dysfunction. Here we evaluated whether ASCs isolated from nonobese and obese tissue differed in their metabolic characteristics and differentiation potential. During differentiation to mature adipocytes, mouse and human ASCs derived from nonobese tissues both increased their insulin sensitivity and inhibition of lipolysis, whereas obese-derived ASCs were insulin-resistant, showing impaired insulin-stimulated glucose uptake and resistance to the antilipolytic effect of insulin. Furthermore, obese-derived ASCs showed enhanced release of proinflammatory cytokines and impaired production of adiponectin. Interestingly, the delivery of cytosol from control ASCs into obese-derived ASCs using a lipid-based, protein-capture methodology restored insulin sensitivity on glucose and lipid metabolism and reversed the proinflammatory cytokine profile, in part due to the restoration of Lin28 protein levels. In conclusion, glucose and lipid metabolism as well as maturation of ASCs is truncated in an obese environment. The reversal of the altered pathways in obese cells by delivery of normal subcellular fractions offers a potential new tool for cell therapy.

GRK2 contribution to the regulation of energy expenditure and brown fat function

Obesity is a major health problem and an important risk factor for the development of multiple disorders. Previous studies in our laboratory have revealed that down-regulation of GRK2 decreases age-related adiposity, but the physiological and molecular mechanisms underlying this outcome remain unclear. We evaluate whether the lean phenotype results from a direct effect of GRK2 on energy homeostasis. The study of white adipose tissue (WAT) in wild-type (WT) and GRK2(+/-) littermates showed a reduced expression of lipogenic enzymes and enhanced lipolytic rate in adult GRK2(+/-) mice. Moreover, hemizygous mice display higher energy expenditure and lower respiratory exchange ratio. Analysis of brown adipose tissue (BAT) from adult GRK2(+/-) mice showed a less deteriorated morphology associated with age compared to WT, which is correlated with a higher basal core temperature. BAT from young GRK2(+/-) mice showed an increase in gene expression of thermogenesis-related genes. Accordingly, hemizygous mice displayed better thermogenic capacity and exhibited a more oxidative phenotype in both BAT and WAT than WT littermates. Overexpression of GRK2 in brown adipocytes corroborated the negative effect of this kinase in BAT function and differentiation. Collectively, our data point to GRK2 inhibition as a potential tool for the enhancement of brown fat activity, which may have important therapeutic implications for the treatment of obesity and associated metabolic disorders.

New emerging role of protein-tyrosine phosphatase 1B in the regulation of glycogen metabolism in basal and TNF-α-induced insulin-resistant conditions in an immortalised muscle cell line isolated from mice

AIMS/HYPOTHESIS

Protein-tyrosine phosphatase 1B (PTP1B) negatively regulates insulin action, promoting attenuation of the insulin signalling pathway. The production of this phosphatase is enhanced in insulin-resistant states, such as obesity and type 2 diabetes, where high levels of proinflammatory cytokines (TNF-α, IL-6) are found. In these metabolic conditions, insulin action on glycogen metabolism in skeletal muscle is greatly impaired. We addressed the role of PTP1B on glycogen metabolism in basal and insulin-resistant conditions promoted by TNF-α.

METHODS

We studied the effect of TNF-α in the presence and absence of insulin on glycogen content and synthesis, glycogen synthase (GS) and glycogen phosphorylase (GP) activities and on glycogen synthesis and degradation signalling pathways. For this purpose we used immortalised cell lines isolated from skeletal muscle from mice lacking PTP1B.

RESULTS

Absence of PTP1B caused activation of GS and GP with a net glycogenolytic effect, reflected in lower amounts of glycogen and activation of the glycogenolytic signalling pathway, with higher rates of phosphorylation of cyclic adenosine monophosphate-dependent kinase (PKA), phosphorylase kinase (PhK) and GP phosphorylation. Nevertheless, insulin action was strongly enhanced in Ptp1b (also known as Ptpn1)(-/-) cells in terms of glycogen content, synthesis, GS activation rates and GS Ser641 dephosphorylation. Treatment with TNF-α augmented the activity ratios of both GS and GP, and impaired insulin stimulation of glycogen synthesis in wild-type myocytes, whereas Ptp1b (-/-) myocytes restored this inhibitory effect. We report a glycogenolytic effect of TNF-α, as demonstrated by greater activation of the degradation signalling cascade PKA/PhK/GP. In our model, this effect is mediated by the activation of PKA.

CONCLUSIONS/INTERPRETATION

We provide new data about the role of PTP1B in glycogen metabolism and confirm the beneficial effect that absence of the phosphatase confers against an insulin-resistant condition.

G protein-coupled receptor kinase 2 plays a relevant role in insulin resistance and obesity

OBJECTIVE

Insulin resistance is associated with the pathogenesis of metabolic disorders as type 2 diabetes and obesity. Given the emerging role of signal transduction in these syndromes, we set out to explore the possible role that G protein-coupled receptor kinase 2 (GRK2), first identified as a G protein-coupled receptor regulator, could have as a modulator of insulin responses.

RESEARCH DESIGN AND METHODS

We analyzed the influence of GRK2 levels in insulin signaling in myoblasts and adipocytes with experimentally increased or silenced levels of GRK2, as well as in GRK2 hemizygous animals expressing 50% lower levels of this kinase in three different models of insulin resistance: tumor necrosis factor-α (TNF-α) infusion, aging, and high-fat diet (HFD). Glucose transport, whole-body glucose and insulin tolerance, the activation status of insulin pathway components, and the circulating levels of important mediators were measured. The development of obesity and adipocyte size with age and HFD was analyzed.

RESULTS

Altering GRK2 levels markedly modifies insulin-mediated signaling in cultured adipocytes and myocytes. GRK2 levels are increased by ∼2-fold in muscle and adipose tissue in the animal models tested, as well as in lymphocytes from metabolic syndrome patients. In contrast, hemizygous GRK2 mice show enhanced insulin sensitivity and do not develop insulin resistance by TNF-α, aging, or HFD. Furthermore, reduced GRK2 levels induce a lean phenotype and decrease age-related adiposity.

CONCLUSIONS

Overall, our data identify GRK2 as an important negative regulator of insulin effects, key to the etiopathogenesis of insulin resistance and obesity, which uncovers this protein as a potential therapeutic target in the treatment of these disorders.

Adenosine 5'-monophosphate-activated protein kinase-mammalian target of rapamycin cross talk regulates brown adipocyte differentiation

Brown adipose tissue (BAT) is considered of metabolic significance in mammalian physiology, because it plays an important role in regulating energy balance. Alterations in this tissue have been associated with obesity and type 2 diabetes. The molecular mechanisms modulating brown adipocyte differentiation are not fully understood. Using a murine brown preadipocyte cell line, primary cultures, and 3T3-L1 cells, we analyzed the contribution of various intracellular signaling pathways to adipogenic and thermogenic programs. Sequential activation of p38MAPK and LKB1-AMPK-tuberous sclerosis complex 2 (TSC2) as well as significant attenuation of ERK1/2 and mammalian target of rapamycin (mTOR)-p70 S6 kinase 1 (p70S6K1) activation was observed through the brown differentiation process. This study demonstrates a critical role for AMPK in controlling the mTOR-p70S6K1 signaling cascade in brown but not in 3T3-L1 adipocytes. We observed that mTOR activity is essential in the first stages of differentiation. Nevertheless, subsequent inhibition of this cascade by AMPK activation is also necessary at later stages. An in vivo study showed that prolonged 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR)-induced AMPK activation increases uncoupling protein 1 expression and induces an accumulation of brown adipocytes in white adipose tissue (WAT), as revealed by immunohistology. Moreover, the induction of brown adipogenesis in areas of white fat partially correlates with the body weight reduction detected in response to treatment with AICAR. Taken together, our study reveals that differentiation of brown adipocytes employs different signaling pathways from white adipocytes, with AMPK-mTOR cross talk a central mediator of this process. Promotion of BAT development in WAT by pharmacological activation of AMPK may have potential in treating obesity by acting on energy dissipation.

Molecular mechanisms involved in obesity-associated insulin resistance: therapeutical approach

Insulin resistance is an important contributor to the pathogenesis of T2D and obesity is a risk factor for its development. It has been demonstrated that these obesity-related metabolic disorders are associated with a state of chronic low-intensity inflammation. Several mediators released from adipocytes and macrophages, such as the pro-inflammatory cytokines TNF-alpha and IL-6, have been suggested to impair insulin action in peripheral tissues, including fat and skeletal muscle. Such insulin resistance can initially be compensated by increased insulin secretion, but the prolonged presence of the hormone is detrimental for insulin sensitivity. Stress and pro-inflammatory kinases as well as more recent players, phosphatases, seem to be involved in the molecular mechanisms by which pro-inflammatory cytokines and hyperinsulinemia disrupt insulin signalling at the level of IRSs. Pharmacological approaches, such as treatment with PPAR and LXR agonists, overcome such insulin resistance, exerting anti-inflammatory properties as well as controlling the expression of cytokines with tissular specificity.

c-Jun N-terminal kinase 1/2 activation by tumor necrosis factor-alpha induces insulin resistance in human visceral but not subcutaneous adipocytes: reversal by liver X receptor agonists

AIMS

Obesity is associated with a chronic systemic low-grade inflammatory state. Markers of inflammation such as TNF-alpha are linked with increased risk for insulin resistance and type 2 diabetes. The objective of the present study was to dissect the molecular mechanisms that may regulate TNF-alpha-induced insulin resistance in human adipose tissue.

METHODS

We analyzed the impact of TNF-alpha on glucose uptake and insulin action in human visceral and sc adipocytes. The contribution of different intracellular signaling pathways on metabolic effects of TNF-alpha and the reversal of some of these effects with nuclear receptor agonists were also studied.

RESULTS

TNF-alpha per se increased glucose transporter-4 translocation to the plasma membrane and glucose uptake by activating the AMP-activated protein kinase/AS160 pathway in both visceral and sc adipocytes. Nevertheless, this cytokine induced an insulin-resistant state in visceral adipocytes by impairing insulin-stimulated glucose uptake and insulin signaling at the insulin receptor substrate (IRS)-1/AKT level. Activation of c-Jun N-terminal kinase (JNK) 1/2 seems to be involved in TNF-alpha-induced insulin resistance, causing phosphorylation of IRS1 at the Ser312 residue. Accordingly, silencing JNK1/2 with either small interfering RNA or chemical inhibitors impaired serine phosphorylation of IRS1, restored downstream insulin signaling, and normalized insulin-induced glucose uptake in the presence of TNF-alpha. Furthermore, TNF-alpha increased the secretion of other proinflammatory cytokines such as IL-6. Pharmacological treatment of adipocytes with liver X receptor agonists reestablished insulin sensitivity by impairing TNF-alpha induction of JNK1/2, phosphorylation of IRS1 (Ser312), and stabilizing IL-6 secretion.

CONCLUSIONS

TNF-alpha induces insulin resistance on glucose uptake in human visceral but not sc adipocytes, suggesting depot-specific effects of TNF-alpha on glucose uptake. Activation of JNK1/2 appears to be involved in serine phosphorylation of IRS1 and subsequently insulin resistance on glucose uptake, a state that can be reversed by liver X receptor agonists.

Dual role of interleukin-6 in regulating insulin sensitivity in murine skeletal muscle

OBJECTIVE

Cytokines are elevated in various insulin-resistant states, including type 2 diabetes and obesity, although the contribution of interleukin-6 (IL-6) in the induction of these diseases is controversial.

RESEARCH DESIGN AND METHODS

We analyzed the impact of IL-6 on insulin action in murine primary myocytes, skeletal muscle cell lines, and mice (wild type and protein-tyrosine phosphatase 1B [PTP1B] deficient).

RESULTS

IL-6 per se increased glucose uptake by activating serine/threonine protein kinase 11 (LKB1)/AMP-activated protein kinase/protein kinase B substrate of 160 kDa (AS160) pathway. A dual effect on insulin action was observed when myotubes and mice were exposed to this cytokine: additive with short-term insulin (increased glucose uptake and systemic insulin sensitivity) but chronic exposure produced insulin resistance (impaired GLUT4 translocation to plasma membrane and defects in insulin signaling at the insulin receptor substrate 1 [IRS-1] level). Three mechanisms seem to operate in IL-6-induced insulin resistance: activation of c-Jun NH(2)-terminal kinase 1/2 (JNK1/2), accumulation of suppressor of cytokine signaling 3 (socs3) mRNA, and an increase in PTP1B activity. Accordingly, silencing JNK1/2 with either small interfering RNA or chemical inhibitors impaired phosphorylation of IRS-1 (Ser307), restored insulin signaling, and normalized insulin-induced glucose uptake in myotubes. When using a pharmacological approach, liver X receptor agonists overcome IL-6-induced insulin resistance by producing downregulation of socs3 and ptp1b gene expression. Finally, the lack of PTP1B confers protection against IL-6-induced insulin resistance in skeletal muscle in vitro and in vivo, in agreement with the protection against the IL-6 hyperglycemic effect observed on glucose and insulin tolerance tests in adult male mice.

CONCLUSIONS

These findings indicate the important role of IL-6 in the pathogenesis of insulin resistance and further implicate PTP1B as a potential therapeutic target in the treatment of type 2 diabetes.

Hyperinsulinemia induces insulin resistance on glucose and lipid metabolism in a human adipocytic cell line: paracrine interaction with myocytes

CONTEXT

Adipocytes release a variety of factors which deregulation could provide the basis for complications such as insulin resistance, an early defect on the onset of type 2 diabetes. Such insulin resistance can initially be overcome by compensatory hyperinsulinemia, but the prolonged presence of the hormone can be detrimental for insulin sensitivity.

OBJECTIVE

The objective of the study was to dissect the molecular mechanisms that may regulate hyperinsulinemia-induced insulin resistance in a human liposarcoma cell line and its paracrine interactions with a human rhabdomyosarcoma cell line.

DESIGNS

We studied glucose uptake, lipolysis, insulin signaling, and secretion pattern at different days of adipocyte differentiation in the presence of insulin.

RESULTS

Adipocytes differentiated for 14 d gain insulin sensitivity on glucose uptake and inhibition of lipolysis, but prolonged cultures develop an insulin-resistant state characterized by an increase in phosphatase and tensin homolog-deleted on chromosome 10 expression and defects in insulin signaling at the insulin receptor substrate-1/AKT level. The secretion pattern of nonesterified fatty acids, IL-6, adiponectin, leptin, and monocyte chemotactic protein-1 was in keeping with the changes in insulin sensitivity during differentiation. An inverse biphasic response was also observed in human myocytes when they were cultured with various adipocyte-conditioned media, although insulin resistance was detected earlier than in adipocytes. This behavior mimics hyperinsulinemia because insulin action was restored when adipocytes were cultured in the absence of the hormone. Pharmacological treatment of adipocytes with a liver X receptor agonist reestablishes insulin-stimulated glucose uptake, whereas treatment with a peroxisome proliferator-activated receptor-gamma agonist restored the antilipolytic action of insulin.

CONCLUSIONS

Hyperinsulinemia deregulates adipocyte secretion pattern, producing insulin resistance in adipocytes and myocytes, a situation that can be ameliorated with nuclear receptor agonists.

Insulin resistance associated to obesity: the link TNF-alpha

Adipose tissue secretes proteins which may influence insulin sensitivity. Among them, tumour necrosis factor (TNF)-alpha has been proposed as a link between obesity and insulin resistance because TNF-alpha is overexpressed in adipose tissue from obese animals and humans, and obese mice lacking either TNF-alpha or its receptor show protection against developing insulin resistance. The activation of proinflammatory pathways after exposure to TNF-alpha induces a state of insulin resistance in terms of glucose uptake in myocytes and adipocytes that impair insulin signalling at the level of the insulin receptor substrate (IRS) proteins. The mechanism found in brown adipocytes involves Ser phosphorylation of IRS-2 mediated by TNF-alpha activation of MAPKs. The Ser307 residue in IRS-1 has been identified as a site for the inhibitory effects of TNF-alpha in myotubes, with p38 mitogen-activated protein kinase (MAPK) and inhibitor kB kinase being involved in the phosphorylation of this residue. Moreover, up-regulation of protein-tyrosine phosphatase (PTP)1B expression was recently found in cells and animals treated with TNF-alpha. PTP1B acts as a physiological negative regulator of insulin signalling by dephosphorylating the phosphotyrosine residues of the insulin receptor and IRS-1, and PTP1B expression is increased in peripheral tissues from obese and diabetic humans and rodents. Accordingly, down-regulation of PTP1B activity by treatment with pharmacological agonists of nuclear receptors restores insulin sensitivity in the presence of TNF-alpha. Furthermore, mice and cells deficient in PTP1B are protected against insulin resistance induced by this cytokine. In conclusion, the absence or inhibition of PTP1B in insulin-target tissues could confer protection against insulin resistance induced by cytokines.

Vena cava filters: a synopsis of complications and related topics

Deep venous thrombosis and pulmonary embolism constitute common preventable causes of morbidity and mortality. The incidence of venous thromboembolism (VTE) continues to increase. Standard anticoagulation therapy may reduce the risk of fatal PE by 75% and that of recurrent VTE by over 90%. For patients who are not candidates for anticoagulation, a vena cava filter (VCF) may be beneficial. Despite a good overall safety record, significant complications related to VCF are occasionally seen. This review discusses both procedural and non-procedural complications associated with VCF placement and use. We will also discuss VCF use in the settings of pregnancy, malignancy, and the clinical need for more than one filter.

Nuclear exclusion of forkhead box O and Elk1 and activation of nuclear factor-kappaB are required for C2C12-RasV12C40 myoblast differentiation

Activating ras point mutations are frequently found in skeletal muscle tumors such as rhabdomyosarcomas. In this study we investigated the impact of two different H-ras mutants in skeletal muscle differentiation: RasV12, a constitutively active form, and RasV12C40, a mutant deficient in Raf1 activation. Stably transfected C2C12-RasV12 myoblasts actively proliferated as indicated by the sustained expression of proliferating cell nuclear antigen and retinoblastoma at the hyperphosphorylated state and failed to express differentiation markers. This differentiation-defective phenotype was a consequence of the chronic p44/p42MAPK phosphorylation and the inability of the cells to activate AKT. Moreover, we observed that p44/p42MAPK activation in C2C12-RasV12 myoblasts phosphorylated the ETS-like transcription factor (ELK) 1, which translocates to the nuclei and seemed to be involved in maintaining myoblast proliferation. C2C12-RasV12C40 myoblasts cultured in low serum repressed phosphorylation of p44/p42MAPK and ELK1, resulting in cell cycle arrest and myogenic differentiation. Under this condition, activation of AKT, p70S6K, and p38MAPK was produced, leading to formation of myotubes in 3 d, 1 d earlier than in control C2C12-AU5 cells. Moreover, the expression of muscle-specific proteins, mainly the terminal differentiation markers caveolin-3 and myosin heavy chain, also occurred 1 d earlier than in control cells. Furthermore, AKT activation produced phosphorylation of Forkhead box O that led to nuclear exclusion and inactivation, allowing myogenesis. In addition, we found an induction of nuclear factor-kappaB activity in the nucleus in C2C12-RasV12C40 myotubes attributed to p38MAPK activation. Accordingly, muscle differentiation is associated with a pattern of transcription factors that involves nuclear exclusion ELK1 and Forkhead box O and the increase in nuclear factor-kappaB DNA binding.

Insulin resistance induced by tumor necrosis factor-alpha in myocytes and brown adipocytes

Insulin resistance is an important contributor to the pathogenesis of type 2 diabetes, and obesity is a risk factor for its development, in part because adipose tissue secretes proteins, called adipokines, that may influence insulin sensitivity. Among these molecules, tumor necrosis factor (TNF)-alpha has been proposed as a link between obesity and insulin resistance because TNF-alpha is overexpressed in adipose tissues of obese animals and humans, and obese mice lacking either TNF-alpha or its receptor show protection against developing insulin resistance. Direct exposure to TNF-alpha induces a state of insulin resistance in terms of glucose uptake in myocytes and brown adipocytes because of the activation of proinflammatory pathways that impair insulin signaling at the level of the insulin receptor substrate (IRS) proteins. In this regard, the Ser(307) residue in IRS-1 has been identified as a site for the inhibitory effects of TNF-alpha in myotubes, with p38 mitogen-activated protein kinase and inhibitor kB kinase being involved in the phosphorylation of this residue. Conversely, Ser phosphorylation of IRS-2 mediated by TNF-alpha activation of mitogen-activated protein kinase was the mechanism found in brown adipocytes. Protein-Tyr phosphatase (PTP)1B acts as a physiological, negative regulator of insulin signaling by dephosphorylating the phosphotyrosine residues of the insulin receptor and IRS-1, and PTP1B expression is increased in muscle and white adipose tissue of obese and diabetic humans and rodents. Moreover, up-regulation of PTP1B expression was recently found in cells treated with TNF-alpha Accordingly, myocytes and primary brown adipocytes deficient in PTP1B are protected against insulin resistance induced by this cytokine. Furthermore, down-regulation of PTP1B activity is possible by the use of pharmacological agonists of nuclear receptors that restore insulin sensitivity in the presence of TNF-alpha. In conclusion, the lack of PTP1B in muscle and brown adipocytes increases insulin sensitivity and glucose uptake and could confer protection against insulin resistance induced by adipokines.

Surgical critical care: from old boundaries to new frontiers

The surgical specialty of critical care has evolved into a field where the surgeon manages complex medical and surgical problems in critically ill patients. As a specialty, surgical critical care began when acutely ill surgical patients were placed in a designated area within a hospital to facilitate the delivery of medical care. As technology evolved to allow for development of increasingly intricate and sophisticated adjuncts to care, there has been recognition of the importance of physician availability and continuity of care as key factors in improving patient outcomes. Guidelines and protocols have been established to ensure quality improvement and are essential to licensing by state and national agencies. The modern ICU team provides continuous daily care to the patient in close communication with the primary operating physician. While the ultimate responsibility befalls the primary physician who performed the preoperative evaluation and operative procedure, the intensivist is expected to establish and enforce protocols, guidelines and patient care pathways for the critical care unit. It is difficult to imagine modern surgical ICU care without the surgical critical care specialist at the helm.

Functional impairment in patients with mania: baseline results of the EMBLEM study

OBJECTIVES

The European Mania in Bipolar Longitudinal Evaluation of Medication (EMBLEM) is a large-scale prospective observational multicentre study to evaluate the longitudinal course of bipolar disorder and its associations with pharmacological treatment following an acute manic or mixed episode. We present an overview of the study design and patient characteristics at baseline while focusing on factors influencing work performance in the year prior to enrollment.

METHODS

A total of 530 investigators across 14 European countries enrolled 3,681 patients with acute mania between December 2002 and June 2004. Longitudinal observations are ongoing until July 2006. Socio-demographic variables, psychiatric history, clinical status and information on pharmacological treatment for bipolar disorder were recorded. Items from the SLICE of LIFE were applied, including a measure of work impairment during the previous year. The distribution of the baseline characteristics was analysed with descriptive statistics. Eighteen variables were investigated as hypothesized risk factors for work impairment applying logistic regression models.

RESULTS

In the previous year, 28 and 68% of patients were classified as having 'low' and 'high' work impairment, respectively. Clinical Global Impression - Bipolar Disorder (CGI-BP) overall, CGI-BP depression at baseline, rapid cycling during the previous 12 months, age between 35 and 64 years, substance abuse other than alcohol and cannabis and living without a partner or as dependent household member were significantly associated with work impairment during the previous year.

CONCLUSIONS

EMBLEM is to our knowledge the largest prospective observational study assessing patients during and after an acute episode of mania. Work impairment is significant in the year prior to an acute episode of mania.

Protein-tyrosine phosphatase 1B-deficient myocytes show increased insulin sensitivity and protection against tumor necrosis factor-alpha-induced insulin resistance

Protein-tyrosine phosphatase (PTP)1B is a negative regulator of insulin signaling and a therapeutic target for type 2 diabetes. In this study, we have assessed the role of PTP1B in the insulin sensitivity of skeletal muscle under physiological and insulin-resistant conditions. Immortalized myocytes have been generated from PTP1B-deficient and wild-type neonatal mice. PTP1B(-/-) myocytes showed enhanced insulin-dependent activation of insulin receptor autophosphorylation and downstream signaling (tyrosine phosphorylation of insulin receptor substrate [IRS]-1 and IRS-2, activation of phosphatidylinositol 3-kinase, and serine phosphorylation of AKT), compared with wild-type cells. Accordingly, PTP1B(-/-) myocytes displayed higher insulin-dependent stimulation of glucose uptake and GLUT4 translocation to the plasma membrane than wild-type cells. Treatment with tumor necrosis factor-alpha (TNF-alpha) induced insulin resistance on glucose uptake, impaired insulin signaling, and increased PTP1B activity in wild-type cells. Conversely, the lack of PTP1B confers protection against insulin resistance by TNF-alpha in myocyte cell lines and in adult male mice. Wild-type mice treated with TNF-alpha developed a pronounced hyperglycemia along the glucose tolerance test, accompanied by an impaired insulin signaling and increased PTP1B activity in muscle. However, mice lacking PTP1B maintained a rapid clearance of glucose and insulin sensitivity and displayed normal muscle insulin signaling regardless the presence of TNF-alpha.

Liver X receptor agonists ameliorate TNFalpha-induced insulin resistance in murine brown adipocytes by downregulating protein tyrosine phosphatase-1B gene expression

AIMS/HYPOTHESIS

The nuclear receptors, including nuclear receptor subfamily 1, group H, member 3 (NR1HR, also known as liver X receptor [LXR]), are sensors of cholesterol metabolism and lipid biosynthesis that have recently been proposed as insulin sensitisers. TNFalpha has been described as a link between obesity and the development of insulin resistance, an important contributor to the pathogenesis of type 2 diabetes. Therefore, we decided to investigate the ability of NR1HR agonists to ameliorate TNFalpha-induced insulin resistance in brown adipocytes.

METHODS

Primary brown adipocytes from rat fetuses, and from wild-type neonate mice and neonate mice deficient in the gene encoding protein tyrosine phosphatase-1B (Ptpn1, also known as Ptp1b) were cultured in the absence or presence of TNFalpha and different nuclear receptor agonists. Among them, the unrelated NR1HR ligands T0901317, GW3965 and (22R)-hydroxycholesterol were tested. After insulin stimulation, glucose uptake and solute carrier family 2 (facilitated glucose transporter), member 4 (SLC2A4, formerly known as GLUT4) translocation were measured. Next the insulin signalling cascade was determined by submitting cells to lysis, immunoprecipitation and immunoblotting.

RESULTS

NR1HR agonists ameliorate TNFalpha-induced insulin resistance restoring completely insulin-stimulated glucose uptake and SLC2A4 translocation to plasma membrane. This effect is parallel to the recovery of the insulin cascade insulin receptor/IRS-2/phosphatidylinositol 3-kinase/protein kinase B, and could be due to the fact that T0901317 prevents the increase of PTPN1 production and phosphatase activity produced by TNFalpha. In this regard, Ptpn1-deficient brown adipocytes showed protection against insulin resistance by TNFalpha. Moreover, we observed that T0901317 produced in itself a significant increase over basal glucose uptake consistent with an increase of SLC2A4 protein content in plasma membrane, attributable to the activation of protein kinase zeta and/or the increase of Slc2a4 expression.

CONCLUSIONS/INTERPRETATION

Nuclear receptors NR1HR are interesting potential targets for drug treatment of insulin resistance.

BioEnterics Intragastric Balloon (BIB): a short-term, double-blind, randomised, controlled, crossover study on weight reduction in morbidly obese patients

BACKGROUND

The BioEnterics Intragastric Balloon (BIB) System in association with restricted diet has been used for the short-term treatment of morbid obesity. Aim of this study was to evaluate the real, short term, efficacy of the BIB for weight reduction in morbidly obese patients by using a prospective, double-blind, randomised, sham-controlled, crossover study.

METHODS

Patients were recruited from January 2003 to December 2003. After selection, they were randomly allocated into two groups: BIB followed by sham procedure after 3 months (Group A), and sham procedure followed by BIB after 3 months (Group B). All endoscopic procedures were performed under unconscious intravenous sedation. The BioEnterics Intragastric Balloon (Inamed Health; Santa Barbara, CA, USA) was filled by using saline (500 ml) and methylene blue (10 ml). Patients were discharged with omeprazole therapy and diet (1000 kcal). Patients were followed up weekly by a physician blinded to randomisation. In both groups mortality, complications, BMI, BMI reduction and %EWL were considered. Data were expressed as mean +/- s.d., except as otherwise indicated. Statistical analysis was performed by means of Student's t-test, Fisher's exact test or chi (2) with Yates correction; P < 0.05 was considered significant.

RESULTS

A total of 32 patients were selected and entered the study (8M/24F; mean age: 36.2 +/- 5.6 years, range 25-50 years; mean BMI 43.7+/-1.5 kg/m(2), range 40-45 kg/m(2); mean %EW: 43.1 +/- 13.1, range: 35-65). All patients completed the study. Mortality was absent. Complications related to endoscopy, balloon placement and removal were absent. Mean time of BIB positioning was 15 +/- 2 min, range 10-20 min. After the first 3 months of the study, in Group A patients the mean BMI significantly (P < 0.001) lowered from 43.5 +/- 1.1 to 38.0 +/- 2.6 kg/m(2), while in Group B patients the decrease was not significant (from 43.6 +/- 1.8 to 43.1 +/- 2.8 kg/m(2)). The mean %EWL was significantly higher in Group A than in Group B (34.0 +/- 4.8 vs 2.1 +/- 1%; P < 0.001). After crossover, at the end of the following 3 months, the BMI lowered from 38.0 +/- 2.6 to 37.1 +/- 3.4 kg/m(2) and from 43.1 +/- 2.8 to 38.8 +/- 3.1 kg/m(2) in Groups A and B, respectively.

CONCLUSIONS

The results of this study show that treatment of obese patients with BioEnterics Intragastric Balloon is a safe and effective procedure. In association with appropriate diet it is significantly effective in weight reduction when compared to sham procedure plus diet. The BIB procedure can play a role in weight reduction in morbidly obese patients or in the preoperative treatment of bariatric patients.