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Background: The Global Diet Quality Score (GDQS) was developed to be a simple, timely and cost-effective tool to track, simultaneously, nutritional deficiency and non-communicable disease risks from diet in diverse settings. The objective was to investigate the performance of GDQS as an indicator of adequate nutrient intake and dietary quality in a national-representative sample of the Brazilian population., Methods: Nationally-representative data from 44,744 men and non-pregnant and non-lactating women aging ≥ 10 years, from the Brazilian National Dietary Survey were used. Dietary data were collected through two 24-h recalls (24HR). The GDQS was calculated and compared to a proxy indicator of nutrient adequate intake (the Minimum Dietary Diversity for Women-MDD-W) and to an indicator of high-risk diet for non-communicable diseases (caloric contribution from ultra-processed foods-UPF). To estimate the odds for overall nutrient inadequacy across MDD-W and GDQS quintiles, a multiple logistic regression was applied, and the two metrics' performances were compared using Wald's post-test., Results: The mean GDQS for Brazilians was 14.5 (0-49 possible range), and only 1% of the population had a low-risk diet (GDQS ≥ 23). The GDQS mean was higher in women, elderly individuals and in higher-income households. An inverse correlation was found between the GDQS and UPF (rho (95% CI) = -0.20(-0.21;-0.19)). The odds for nutrient inadequacy were lower as quintiles of GDQS and MDD-W were higher (p-trend < 0.001), and MDD-W had a slightly better performance than GDQS (p-diff < 0.001). Having a low-risk GDQS (≥ 23) lowered the odds for nutrient inadequacy by 74% (95% CI:63%-81%)., Conclusion: The GDQS is a good indicator of overall nutrient adequacy, and correlates well with UPF in a nationally representative sample of Brazil. Future studies must investigate the relationship between the GDQS and clinical endpoints, strengthening the recommendation to use this metric to surveillance dietary risks., (© 2024. The Author(s).)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a major global outbreak of respiratory tract disease known as Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 infects mainly lungs and may cause several immune-related complications, such as lymphocytopenia and cytokine storm, which are associated with the severity of the disease and predict mortality. The mechanism by which SARS-CoV-2 infection may result in immune system dysfunction is still not fully understood. Here, we show that SARS-CoV-2 infects human CD4 + T helper cells, but not CD8 + T cells, and is present in blood and bronchoalveolar lavage T helper cells of severe COVID-19 patients. We demonstrated that SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule, which in turn mediates the entry of SARS- CoV-2 in T helper cells. This leads to impaired CD4 T cell function and may cause cell death. SARS-CoV-2-infected T helper cells express higher levels of IL-10, which is associated with viral persistence and disease severity. Thus, CD4-mediated SARS-CoV-2 infection of T helper cells may contribute to a poor immune response in COVID-19 patients., Competing Interests: NB, GD, Dd, AF, GS, SM, TK, VB, LM, JV, GP, NW, LN, VC, AD, FV, LT, JF, IC, LS, AP, EM, RU, AB, TN, LR, MA, MM, LB, FC, RL, JG, NM, AM, RS, MA, DT, PP, MM, KB, CS, FG, VS, Ed, VF, MC, BC, AP, LC, MD, PR, AG, FP, LS, LB, SS, MP, SW, AS, RC, AV, MV, AD, LV, AF, Ld, TC, HN, HM, RM, DM, MS, JP, PM, MM, AF No competing interests declared, (© 2023, Brunetti, Davanzo, de Moraes et al.)

Background: Studies have shown significant benefits of exercise therapy in heart failure (HF) with a reduced ejection fraction (HFrEF) and HF with a preserved ejection fraction (HFpEF). The mechanisms responsible for the beneficial effect of exercise in HFrEF and HFpEF are still unclear. We hypothesized that the effect of exercise on myocardial remodeling may explain its beneficial effect., Methods: IMAGING-REHAB-HF is a single-center, randomized, controlled clinical trial using cardiac magnetic resonance imaging, vasomotor endothelial function, cardiac sympathetic activity imaging and serum biomarkers to compare the effect of exercise therapy in HFpEF (LVEF ≥ 45%) and HFrEF (LVEF < 45%). Subjects will be assessed at baseline and after 4 months. The exercise program will consist of three 60-min exercise sessions/week. The primary endpoints are the effect of exercise on myocardial extracellular volume (ECV), left ventricular (LV) systolic function, LV mass, LV mass-to-volume and LV cardiomyocyte volume. Secondary endpoints include the effect of exercise on vasomotor endothelial function, cardiac sympathetic activity and plasmatic biomarkers. Patients will be allocated in a 2:1 fashion to supervised exercise program or usual care. A total sample size of 90 patients, divided into two groups according to LVEF:HFpEF group (45 patients:30 in the intervention arm and 15 in the control arm) and HFrEF group (45 patients:30 in the intervention arm and 15 in the control arm) - will be necessary to achieve adequate power., Conclusion: This will be the first study to evaluate the benefits of a rehabilitation program on cardiac remodeling in HF patients. The unique design of our study may provide unique data to further elucidate the mechanisms involved in reverse cardiac remodeling after exercise in HFpEF and HFrEF patients., Competing Interests: Conflict of interest statement: The author(s) declared following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr. Neilan reports consultancy for Parexel, Intrinsic Imaging, BMS and Aprea Therapeutics unrelated to the contents of this article. The other authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Objectives: The goal of this study was to demonstrate that cardiac magnetic resonance could reveal anthracycline-induced early tissue remodeling and its relation to cardiac dysfunction and left ventricular (LV) atrophy., Background: Serum biomarkers of cardiac dysfunction, although elevated after chemotherapy, lack specificity for the mechanism of myocardial tissue alterations., Methods: A total of 27 women with breast cancer (mean age 51.8 ± 8.9 years, mean body mass index 26.9 ± 3.6 kg/m 2 ), underwent cardiac magnetic resonance before and up to 3 times after anthracycline therapy. Cardiac magnetic resonance variables were LV ejection fraction, normalized T2-weighted signal intensity for myocardial edema, extracellular volume (ECV), LV cardiomyocyte mass, intracellular water lifetime (τ ic ; a marker of cardiomyocyte size), and late gadolinium enhancement., Results: At baseline, patients had a relatively low (10-year) Framingham cardiovascular event risk (median 5%), normal LV ejection fractions (mean 69.4 ± 3.6%), and normal LV mass index (51.4 ± 8.0 g/m 2 ), a mean ECV of 0.32 ± 0.038, mean τ ic of 169 ± 69 ms, and no late gadolinium enhancement. At 351 to 700 days after anthracycline therapy (240 mg/m 2 ), mean LV ejection fraction had declined by 12% to 58 ± 6% (p < 0.001) and mean LV mass index by 19 g/m 2 to 36 ± 6 g/m 2 (p < 0.001), and mean ECV had increased by 0.037 to 0.36 ± 0.04 (p = 0.004), while mean τ ic had decreased by 62 ms to 119 ± 54 ms (p = 0.004). Myocardial edema peaked at about 146 to 231 days (p < 0.001). LV mass index was associated with τ ic (β = 4.1 ± 1.5 g/m 2 per 100-ms increase in τ ic , p = 0.007) but not with ECV. Cardiac troponin T (mean 4.6 ± 1.4 pg/ml at baseline) increased significantly after anthracycline treatment (p < 0.001). Total LV cardiomyocyte mass, estimated as: (1 - ECV) × LV mass, declined more rapidly after anthracycline therapy, with peak cardiac troponin T >10 pg/ml. There was no evidence for any significant interaction between 10-year cardiovascular event risk and the effect of anthracycline therapy., Conclusions: A decrease in LV mass after anthracycline therapy may result from cardiomyocyte atrophy, demonstrating that mechanisms other than interstitial fibrosis and edema can raise ECV. The loss of LV cardiomyocyte mass increased with the degree of cardiomyocyte injury, assessed by peak cardiac troponin T after anthracycline treatment. (Doxorubicin-Associated Cardiac Remodeling Followed by CMR in Breast Cancer Patients; NCT03000036)., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Obesity has emerged as major public health problem leading to increased morbidity and mortality. Epidemiological studies indicate that in many regions of the world, children and teenagers are increasingly affected by obesity, which contributes for a pessimistic projection for the near future. Maternal obesity has been implicated in metabolic disorders of the offspring, but there are no biological markers that can be detected early on life that predict the development of obesity in the offspring., Objective: To evaluate the expression of inflammatory markers in the umbilical cord blood of babies of mothers with obesity/overweight, and correlate these markers with the body weight at age 9 months., Methods: Anthropometric data of mothers and babies were obtained during prenatal evaluation, at birth and 9 months after birth. Cord blood was collected during delivery of 54 babies from mothers with obesity/overweight and of 50 babies from lean mothers. Tumour necrosis factor-alpha (TNF-α), transforming growth factor 1 beta, monocyte chemoattractant protein-1 and 2 (MCP-1/MCP-2) were determined in serum samples using enzyme-linked immunosorbent assay methods. Correlations were evaluated using the Spearman correlation coefficient, and comparisons were evaluated using the non-parametric Mann-Whitney U -test., Results: Cord blood TNF-α was positively correlated with maternal body mass index. There was an inverse correlation between cord blood transforming growth factor 1 beta and baby body weight at birth. There was no biological marker that predicted body weight at age 9 months., Conclusion: Although we have not found a biological marker to predict increased body weight at 9 months of age, the study shows that maternal obesity exposes the baby to higher TNF-α level in the early stages of life, and this can affect metabolic and inflammatory parameters during adulthood.

Endotoxic hypoglycaemia has an important role in the survival rates of septic patients. Previous studies have demonstrated that hypothalamic AMP-activated protein kinase (hyp-AMPK) activity is sufficient to modulate glucose homeostasis. However, the role of hyp-AMPK in hypoglycaemia associated with endotoxemia is unknown. The aims of this study were to examine hyp-AMPK dephosphorylation in lipopolysaccharide (LPS)-treated mice and to determine whether pharmacological hyp-AMPK activation could reduce the effects of endotoxemia on blood glucose levels. LPS-treated mice showed reduced food intake, diminished basal glycemia, increased serum TNF-α and IL-1β levels and increased hypothalamic p-TAK and TLR4/MyD88 association. These effects were accompanied by hyp-AMPK/ACC dephosphorylation. LPS-treated mice also showed diminished liver expression of PEPCK/G6Pase, reduction in p-FOXO1, p-AMPK, p-STAT3 and p-JNK level and glucose production. Pharmacological hyp-AMPK activation blocked the effects of LPS on the hyp-AMPK phosphorylation, liver PEPCK expression and glucose production. Furthermore, the effects of LPS were TLR4-dependent because hyp-AMPK phosphorylation, liver PEPCK expression and fasting glycemia were not affected in TLR4-mutant mice. These results suggest that hyp-AMPK activity may be an important pharmacological target to control glucose homeostasis during endotoxemia., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

In diet-induced obesity, hypothalamic inflammation is triggered as an outcome of prolonged exposure to dietary fats. Toll-like receptor 4 (TLR4) activation plays a central role in this process, inducing endoplasmic reticulum stress and activating inflammatory cytokine gene transcription. Although saturated fatty acids can induce endoplasmic reticulum stress in the hypothalamus, it is unknown whether inflammatory cytokines alone can activate this mechanism. Here, rats were treated with TNF-α or lyposaccharide (LPS) and endoplasmic reticulum stress and unfolded protein response were evaluated by immunoblot and polymerase chain reaction (PCR). Activation of TLR4 by LPS was capable of inducing a complete endoplasmic reticulum stress and unfolded protein response through the PERK/eIF2α and IRE1α/XBP1 pathways. Conversely, TNF-α, injected either locally or systemically, was unable to induce a complete program of unfolded protein response, although the activation of endoplasmic reticulum stress was achieved to a certain degree. Thus, in the hypothalamus, the isolated action of TNF-α is insufficient to produce the activation of a complete program of unfolded protein response., (Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.)

Here, we report the occurrence of leukocytoclastic vasculitis as an outcome of type III allergy to insulin in a patient with type II diabetes mellitus. The diagnosis was made on the basis of anatomo-pathological examination of a skin biopsy., (Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.)

Pouchitis after total rectocolectomy is the most common complication of ulcerative colitis (UC). The immunological mechanisms involved in the genesis of pouchitis are unclear. Therefore, we evaluated the inflammatory activity in normal ileal pouch mucosa by determining signal transducers and activators of transcription (STAT-1) activation and cytokine expression in patients operated for UC and familial adenomatous polyposis (FAP). Eighteen asymptomatic patients, who underwent total rectocolectomy and J pouch, were evaluated: nine with UC and nine with FAP. The activation of STAT-1 and cytokine expression were determined by immunoblot of total protein extracts from pouch mucosal biopsies. The absence of pouchitis was assessed by clinical, histological and endoscopic parameters, according to the Pouchitis Disease Activity Index. The patients were not receiving any medication. Analysis of variance (anova) and Tukey-Kramer's test were applied. The local ethical committee approved the study and informed consent was signed by all participants. STAT-1 activation was increased in UC when compared to FAP and controls (P < 0.05). Higher levels of interferon (IFN)-gamma expression were observed in UC patients when compared to the control group (P < 0.05), but were similar to FAP. In contrast, cytokine signalling (SOCS-3) and interleukin (IL)-10 expression were similar in all groups (P > 0.05). These findings could explain the higher susceptibility to this inflammatory complication in UC when compared to FAP. A tendency towards increased levels of IFN-gamma and STAT-1 in patients with UC, even without clinical and endoscopic evidence of pouchitis, was observed; studying inflammatory activity in asymptomatic ileal pouches may help understanding of the pathogenesis of pouchitis.

Babies with gastroschisis have high morbidity, which is associated with inflammatory bowel injury caused by exposure to amniotic fluid. The objective of this study was to identify components of the inflammatory response in the intestine and liver in an experimental model of gastroschisis in rats. The model was surgically created at 18.5 days of gestation. The fetuses were exposed through a hysterotomy and an incision at the right of the umbilicus was made, exposing the fetal bowel. Then, the fetus was placed back into the uterus until term. The bowel in this model had macro- and microscopic characteristics similar to those observed in gastroschisis. The study was conducted on three groups of 20 fetuses each: gastroschisis, control, and sham fetuses. Fetal body, intestine and liver weights and intestine length were measured. IL-1beta, IL-6, IL-10, TNF-alpha, IFN-gamma and NF-kappaB levels were assessed by ELISA. Data were analyzed statistically by ANOVA followed by the Tukey post-test. Gastroschisis fetuses had a decreased intestine length (means +/- SD, 125 +/- 25 vs 216 +/- 13.9; P < 0.005) and increased intestine weight (0.29 +/- 0.05 vs 0.24 +/- 0.04; P < 0.005). Intestine length correlated with liver weight only in gastroschisis fetuses (Pearson's correlation coefficient, r = 0.518, P = 0.019). There were no significant differences in the concentrations of IL-1beta, TNF-alpha or IFN-gamma in the intestine, whereas the concentration of NF-kappaB was increased in both the intestine and liver of fetuses with gastroschisis. These results show that the inflammatory response in the liver and intestine of the rat model of gastroschisis is accompanied by an increase in the amount of NF-kappaB in the intestine and liver.

Essential hypertension is an insulin resistant state. Early insulin signaling steps are impaired in essential hypertension and a large body of data suggests that there is a crosstalk at multiple levels between the signal transduction pathways that mediate insulin and angiotensin II actions. At the extracellular level the angiotensin converting enzyme (ACE) regulates the synthesis of angiotensin II and bradykinin that is a powerful vasodilator. At early intracellular level angiotensin II acts on JAK-2/IRS1-IRS2/PI3-kinase, JNK and ERK to phosphorylate serine residues of key elements of insulin signaling pathway therefore inhibiting signaling by the insulin receptor. On another level angiotensin II inhibits the insulin signaling inducing the regulatory protein SOCS 3. Angiotensin II acting through the AT1 receptor can inhibit insulin-induced nitric oxide (NO) production by activating ERK 1/2 and JNK and enhances the activity of NADPH oxidase that leads to an increased reactive oxygen species generation. From the clinical standpoint, the inhibition of the renin angiotensin system improves insulin sensitivity and decreases the incidence of Type 2 Diabetes Mellitus (T2DM). This might represent an alternative approach to prevent type 2 diabetes in patients with hypertension and metabolic syndrome, (i.e. insulin resistant patients). This review will discuss: a) the molecular mechanisms of the crosstalk between the insulin and angiotensin II signaling systems b) the results of clinical studies employing drugs targeting the renin-angiotensin II-aldosterone systems and their role in glucose metabolism and diabetes prevention.

Pathway specific resistance to insulin signaling through PI 3-kinase/Akt/eNOS associated with a normal or hyper-activated MAP kinase signaling in vascular tissues has recently been proposed as a candidate link between cardiovascular disease and insulin resistance. Growth stimulatory pathways other than ERK/MAP kinase, such as JAK/STAT have not yet been investigated in vessels of animal models of insulin resistance. Here we have examined whether insulin is able to activate JAK2/STAT pathway in rat aorta and also the regulation of this pathway in an animal model of obesity/insulin resistance. Our results demonstrate that insulin activates JAK2 tyrosine kinase activity in rat aorta in parallel with the activation of STAT3 and STAT5a/b. Moreover, it is shown that, in obese animals, JAK2/STAT and MAP kinase pathways are hyper-activated in response to insulin, which occurs in association with a reduced activation of PI 3-kinase/Akt pathway in aorta. The results of the present study suggest that, besides ERK/MAP kinase pathway, another potentially pro-atherogenic pathway, JAK2/STAT is hyper-activated in vessels in a state of insulin resistance and this phenomenon, in association with the inhibition of the PI 3-kinase/Akt pathway, may play an important role in the pathogenesis of cardiovascular diseases.

Advanced glycation end products (AGEs) increase with aging and induce signaling alterations that lead to inflammation and dysfunction in several tissues. Aging reduces function and insulin signaling in lacrimal glands (LGs). To evaluate whether AGE signaling and insulin secretion in LGs are altered in aging, 24- and 2-month-old male Wistar rats were compared. Immunohistochemistry with confocal microscopy was used to evaluate AGE, AGE receptor (RAGE) and nuclear factor-kappaB (NF-kappaB) expression in LGs. Basal tear secretion volume, insulin, interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) levels in tears and LGs and peroxidase activity in LG tissue were measured. Insulin secretion from isolated LGs and pancreatic beta-cells was compared in the supernatant of aging and control rats in vitro by RIA after stimulation with 2.8-16.7 mM glucose, carbachol and KCl. AGE, RAGE and NF-kappaB expression was higher in LGs of aging compared with young rats. Basal tear secretion and peroxidase activity were significantly lower in the aging group (P=0.016 for both assays). IL-1beta and TNF-alpha levels were higher in tears of aging rats compared with young rats (P=0.007 and 0.05 respectively); however, even though aging rats were insulin-resistant (as confirmed by the insulin-tolerance test), the insulin levels in the tear film of aging and control rats were similar in vivo and in vitro. The higher expression of AGEs, RAGE and NF-kappaB in LGs of aging rats is accompanied by systemic insulin resistance and may be involved in LG and tear film alterations but does not affect insulin secretion in the tear film. These observations indicate that metabolic events may be related to LG and tear film dysfunctions in aging.

Aims/hypothesis: The coactivator of nuclear receptors, peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) has been implicated in a series of events that contribute to the control of glucose metabolism. We have recently reported the use of a PGC-1alpha antisense oligonucleotide (PGC-1alphaAS) that inhibits up to 60% of PGC-1alpha expression in pancreatic islets, leading to increased insulin secretion. This oligonucleotide was used in this study to try to ameliorate diet-induced type 2 diabetes in a genetically predisposed mouse strain (Swiss mice)., Materials and Methods: Glucose and insulin tolerance tests, euglycaemic-hyperinsulinaemic clamp, immunoprecipitation assays, immunoblotting assays and immunohistochemistry were used in this investigation., Results: Swiss mice became obese and overtly diabetic after 8 weeks of feeding with chow containing 24% saturated fat. One daily dose (1.0 nmol) of PGC-1alphaAS significantly reduced glucose and increased insulin blood levels without affecting food intake and body weight. These effects were accompanied by a reduced area under the glucose curve during an intraperitoneal glucose tolerance test, an increased constant of glucose decay (K(itt)) during an insulin tolerance test, and an increased glucose consumption rate during a euglycaemic-hyperinsulinaemic clamp. Moreover, mice treated with PGC-1alphaAS presented an outstanding reduction of macroscopic and microscopic features of hepatic steatosis. These effects were accompanied by reduced expression or function of a series of proteins involved in lipogenesis., Conclusions/interpretation: PGC-1alpha is an attractive target for pharmacological therapeutics in type 2 diabetes mellitus and diet-induced hepatic steatosis.

Autocrine and paracrine insulin signaling may participate in the fine control of insulin secretion. In the present study, tissue distribution and protein amounts of the insulin receptor and its major substrates, insulin receptor substrate (IRS)-1 and IRS-2, were evaluated in a model of impaired glucose-induced insulin secretion, the protein-deficient rat. Immunoblot and RT-PCR studies showed that the insulin receptor and IRS-2 expression are increased, whilst IRS-1 protein and mRNA contents are decreased in pancreatic islets of protein-deficient rats. Immunohistochemical studies revealed that the insulin receptor and IRS-1 and -2 are present in the great majority of islet cells; however, the greatest staining was localized at the periphery, suggesting a co-localization with non-insulin-secreting cells. Exogenous insulin stimulation of isolated islets promoted higher insulin receptor and IRS-1 and -2 tyrosine phosphorylation in islets from protein-deficient rats, as compared with controls. Moreover, insulin-induced IRS-1- and IRS-2-associated phosphatidylinositol 3-kinase activity are increased in islets of protein-deficient rats. The reduction of IRS-1 and IRS-2 protein expression in islets isolated from protein-deficient rats by the use of antisense IRS-1 or IRS-2 phosphorthioate-modified oligonucleotides partially restored glucose-induced insulin secretion. Thus, the impairment of insulin cell signaling through members of the IRS family of proteins in isolated rat pancreatic islets improves glucose-induced insulin secretion. The present data reinforced the role of insulin paracrine and autocrine signaling in the control of its own secretion.

Insulin resistance is known to play a pivotal role in type 2 diabetes. Senile individuals, besides being prone to insulin resistance and, consequently, to type 2 diabetes, manifest diseases of the central nervous system (CNS) that may be influenced by disturbances of insulin signaling in the brain, such as memory impairment, Parkinson disease, and Alzheimer disease. We investigated the expression and response to insulin of elements involved in the insulin-signaling pathway in the forebrain cortex and cerebellum of rats ages 1 d to 60 wk. The protein content of insulin receptors and SRC homology adaptor protein (SHC) did not change significantly along the time frame analyzed. However, insulin-induced tyrosine phosphorylation of the insulin receptor and SHC, and the association of SHC/growth factor receptor binding protein-2 (GRB2) decreased significantly from d 1 to wk 60 of life in both types of tissues. Moreover, the expression of SH protein tyrosine phosphatase-2 (SHP2), a tyrosine phosphatase involved in insulin signal transduction and regulation of the insulin signal, decreased significantly with age progression, in both the forebrain cortex and the cerebellum of rats. Thus, elements involved in the insulin-signaling pathway are regulated at the expression and/or functional level in the CNS, and this regulation may play a role in insulin resistance in the brain.

Insulin is an important regulator of growth and initiates its action by binding to its receptor, which undergoes tyrosyl autophosphorylation and further enhances its tyrosine kinase activity towards other intermediate molecules, including insulin receptor substrate 1, insulin receptor substrate 2, and Shc. Insulin receptor substrate proteins can dock various src-homology-2-domain-containing signaling proteins, such as the 85 kDa subunit of phosphatidylinositol 3 kinase and growth-factor-receptor-bound protein 2. The serine-threonine kinase is activated downstream to phosphatidylinositol 3 kinase. Shc protein has been shown to directly induce the association with growth-factor-receptor-bound protein 2 and downstream the activation of the mitogen-activated protein kinase. In this study we investigated insulin signal transduction pathways in skin of intact rats by immunoprecipitation and immunoblotting with specific antibodies, and also by immunohistochemistry with anti-insulin-receptor antibody. Our results showed that skin fragments clearly demonstrated the presence of insulin receptor in cell bodies of the epidermis and hair follicles and some faint staining was also detected in fibroblasts of the dermis. It was also observed that acute stimulation with insulin can induce tyrosyl phosphorylation of insulin receptor, that the insulin receptor substrates and Shc proteins serve as signaling molecules for insulin in skin of rats, and that insulin is able to induce association of insulin receptor substrate 1/phosphatidylinositol 3 kinase and Shc/growth-factor-receptor-bound protein 2 in this tissue, as well as phosphorylation of mitogen-activated protein kinase and serine-threonine kinase, demonstrating that proteins involved in early steps of insulin action are expressed in skin of intact rats and are quickly activated after insulin stimulation.

A convulxin (Cvx)-like protein was isolated from Crotalus durissus collilineatus venom by a combination of molecular exclusion and reversed-phase HPLC chromatographies. The molecular mass of the Cvx-like protein in the absence and presence of DTT was 78 kDa and 12-13 kDa, respectively. The Cvx-like protein consisted of two nonidentical polypeptide chains (alpha and beta). The N-terminal amino-acid sequences of the alpha and beta subunits were GLHCPSDWYAYDGHCYKIFNEEMNWED and GFCCPSHWSSYSRYCYKFFSQEMNWEDAEK, respectively, with both subunits having a high content of Glu, Ser, Cys, and Asp. The Cvx-like protein showed high homology with other venom C-type lectins, but had low hemagglutinating activity on intact and trypsinized erythrocytes. The Cvx-like protein stimulated insulin receptor phosphorylation and potentiated insulin secretion from isolated islets in the presence of sub- (2.8 mM) or supra-physiological (16.7 mM) glucose concentrations. These results suggest that the increase in insulin secretion induced by Cvx-like protein may be mediated by a protein tyrosine kinase-dependent pathway and may involve other membrane receptors, such as GP VI or Scr family proteins.

Insulin and leptin have overlapping effects in the control of energy homeostasis, but the molecular basis of this synergism is unknown. Insulin signals through a receptor tyrosine kinase that phosphorylates and activates the docking proteins IRSs (insulin receptor substrates), whereas the leptin receptor and its associated protein tyrosine kinase JAK2 (Janus kinase 2) mediate phosphorylation and activation of the transcription factor STAT3 (signal transducer and activator of transcription). Here, we present evidence for the integration of leptin and insulin signals in the hypothalamus. Insulin induced JAK2 tyrosine phosphorylation, leptin receptor phosphorylation which, in the presence of leptin, augmented the interaction between STAT3 and this receptor. Insulin also increased the leptin-induced phosphorylation of STAT3 and its activation. These results indicate that insulin modulates the leptin signal transduction pathway, and may provide a molecular basis for the coordinated effects of insulin and leptin in feeding behavior and weight control.

Shc protein phosphorylation has been extensively characterized as the initial step that activates a complex mitogenic pathway through its association with Grb2. In the present study, we investigated the adrenergic control of insulin-induced Shc phosphorylation and Shc-Grb2 association, and the modulating effect of streptozotocin-induced diabetes mellitus on Shc phosphorylation and Shc/Grb2 association. Acute treatment with epinephrine, which leads to a normoglycemic insulin-resistant state, does not affect insulin-induced Shc tyrosine phosphorylation or Shc-Grb2 association in liver, muscle, or fat. By contrast, a significant increase in insulin-induced Shc phosphorylation is observed in liver and muscle of rats treated with streptozotocin. The association of Shc/Grb2 is also increased in both tissues following insulin treatment. These data suggest that while epinephrine preserves the insulin-induced phosphorylation of Shc and the mitogenic pathway stimulated by Shc-Grb2 association, treatment with streptozotocin leads to a tissue-specific increase in the activity of the initial step that ultimately results in the activation of the Shc/Grb2 mitogenic pathway.

The Anticarsia gemmatalis nucelopolyhedrovirus (AgMNPV) egt gene was cloned, sequenced and its expression characterized by RT-PCR and western blot analysis. Sequence analysis of the gene indicated the presence of an open reading frame (ORF) of 1482 nucleotides, which codes for a polypeptide of 494 amino acids. ATATA box and a conserved regulatory sequence (CATT) found in other baculovirus early genes were present in the promoter region of the egt gene. A poly-A consensus sequence was present in the 3' untranslated region (3'-UTR) of the gene. Homology comparisons showed that the EGT protein of AgMNPV is most closely related (95.9% amino acid sequence identity) to the EGT from the Choristoneura fumiferana DEF nucleopolyhedrovirus (CfDEF). Transcriptional analysis of the AgMNPV egt gene showed that egt-specific transcripts can be detected both early and late in infection. The EGT protein was detected, by western blot analysis, in the intra- (from 12 to 48 h post-infection) and extra-cellular (from 12 to 96 h post-infection) fractions of infected insect cells. The AgMNPV Bgl II-F fragment, which has homology to the AcMNPV ie-1 gene, was cloned and used to cotransfect SF21 cells with the cloned AgMNPV egt gene. EGT activity was observed, suggesting that AgMNPV ie-1 can transactivate egt expression.

Purpose: Insulin has been acknowledged as a mediator of several physiological events in lacrimal and salivary glands. We investigated the presence of insulin receptors and of insulin-induced autophosphorylation of the insulin receptor and activation of elements involved in the early steps of insulin signaling in lacrimal and salivary glands of rats., Methods: Lacrimal and salivary glands of Wistar rats were removed and processed for immunohistochemistry using anti-insulin receptor and anti-IGF-1 receptor antibodies. The activation of insulin receptors following insulin treatment, and the involvement of insulin receptor substrates-1 and -2, Shc, JAK-2 and STAT-1, were analyzed by immunoprecipitation, followed by SDS-PAGE and immunoblotting of rat lacrimal and salivary glands after exposure to insulin., Results: Insulin and IGF-1 receptors were present in rat lacrimal and salivary glands and were located predominantly in the cytoplasm and plasma membrane. Functional studies demonstrated that insulin induced a dose-dependent phosphorylation of the insulin receptor, IGF-1R, insulin receptor substrates-1 and -2, Shc, and STAT-1. In rats with streptozotocin-induced diabetes mellitus there was a significant reduction in insulin-induced insulin receptor and STAT-1 phosphorylation in the lacrimal gland but not in the salivary gland; there was no influence on Shc phosphorylation in either tissue., Conclusions: The present results indicate that insulin and IGF-1 receptors are expressed in lacrimal and salivary glands, and that insulin can induce the phosphorylation of its receptor and activate elements involved in the early steps of insulin signaling in both tissues.

Objective: The aim of this work was to investigate the effect of vitamin E (VE) supplementation on the formation of autoantibodies against oxidized low density lipoproteins (LDL) in a hyperlipidemic animal model., Methods: Thirty-four male hamsters (Mesocricetus auratus), (4 weeks old) were divided into three groups: Group A (n=9) was fed with standard rodent chow; group B (n=13) was fed with a standard rodent chow plus 2% cholesterol and 10% butter and group C (n=12) was fed with the same diet plus 0.2% (w/w) VE. Blood samples were collected by intracardiac puncture and antibody levels were determined in each animal at 4 weeks of age and after 20 weeks of experimental diet. A modified ELISA technique was used to analyze the modulation of autoantibody titers against an epitope of oxidized LDL in serum samples. Antigens prepared for the ELISA tests were characterized using spectrofluorimetry. Serum VE levels were determined in the lipidic fractions by HPLC., Results: The groups fed with cholesterol-fat enriched diet presented a three-fold increase in total serum cholesterol and two-fold increase in serum triglycerides compared to the control group. VE supplementation played no role in serum cholesterol and serum triglyceride concentrations but led to a decreased autoantibody (anti-LDL-malondialdehyde) formation (P<0.05)., Conclusions: Our results show that VE supplementation leads to a lower production of autoantibodies against oxidized LDL, suggesting a protective effect of VE against in vivo oxidation of LDL particles, in a dose-dependent manner.

Insulin stimulates rapid tyrosine phosphorylation of the protein Shc, which subsequently binds to Grb2, resulting in the activation of a complex mitogenic signaling network. In this study, we examined the levels of Shc protein, its phosphorylation state and Shc-Grb2 association in liver, muscle and adipose tissue before and after insulin administration in three animal models of insulin resistance (chronic dexamethasone treatment, 72-h starvation and aging). There were no differences in Shc protein expression between tissues from control and insulin resistant animals. In fasted hypoinsulinemic rats, there was a decrease in insulin-induced Shc phosphorylation in liver and adipose tissue. However, a significant increase in Shc phosphorylation was observed in liver and muscle from dexamethasone-treated hyperinsulinemic rats and in liver, muscle and adipose tissue of hyperinsulinemic 20-month-old rats. Alterations in Shc phosphorylation correlated well with the level of Shc-Grb2 association. These results indicate that Shc tyrosyl phosphorylation and Shc-Grb2 association are regulated in the different types of insulin resistance and that this regulation is apparently related to the animals' plasma insulin levels. The Shc-Grb2 association is directly related to the insulin-induced tyrosyl phosphorylation of Shc.

A growth-related branch of the insulin-signaling pathway was studied in the forebrain cortex and cerebellum of Wistar rats. Anesthetized rats received a bolus injection of saline or insulin through the cava vein after which fragments of cerebellum and forebrain cortex were excised and immediately homogenized. Insulin receptor and p46SHCA phosphorylation, and p46SHCA/GRB2 association were detected by immunoprecipitation and blotting with specific antibodies. Insulin stimulated the rapid phosphorylation of its receptor in cerebellum, followed by p46SHCA phosphorylation and GRB2 recruitment. The optimal insulin dose for the induction of p46SHCA/GRB2 binding was 60 microg, and time-course experiments showed that maximum phosphorylation/binding occurred 2-3 min after stimulation. Although insulin receptors and SHC were present in forebrain cortex, there was no increase in their phosphorylation, nor was there any recruitment of GRB2 following stimulation with insulin. Thus, although elements involved in the early intracellular response to insulin are present in the central nervous system, differences in their activation/regulation may account for the functional roles of insulin in these tissues., (Copyright 1999 Published by Elsevier Science B.V.)

Insulin induces tyrosine phosphorylation of Shc in cell cultures and in insulin-sensitive tissues of the intact rat. However, the ability of insulin receptor (IR) tyrosine kinase to phosphorylate Shc has not been previously demonstrated. In the present study, we investigated insulin-induced IR tyrosine kinase activity towards Shc. Insulin receptor was immunoprecipitated from liver extracts, before and after a very low dose of insulin into the portal vein, and incubated with immunopurified Shc from liver of untreated rats. The kinase assay was performed in vitro in the presence of exogenous ATP and the phosphorylation level was quantified by immunoblotting with antiphosphotyrosine antibody. The results demonstrate that Shc interacted with insulin receptor after infusion of insulin, and, more important, there was insulin receptor kinase activity towards immunopurified Shc. The description of this pathway in animal tissue may have an important role in insulin receptor tyrosine kinase activity toward mitogenic transduction pathways.

Shc is a novel type of tyrosine-phosphorylated protein activated in response to a wide variety of polypeptide ligands. In this study, we used immunoprecipitation and immunoblotting to examine the effect of insulin on Shc tyrosine phosphorylation and Shc/GRB2 association in insulin-sensitive tissues of the intact rat. Following an infusion of insulin, Shc was tyrosine-phosphorylated in the liver, skeletal muscle, and adipose tissue in a time- and dose-dependent fashion, which peaked 5 min after exposure to the hormone and, except in the case of adipose tissue, returned to basal values after 15 min. There was coimmunoprecipitation of Shc and the insulin receptor after stimulation with insulin. Receptor tyrosine kinase activity toward Shc was also observed. Following an infusion of insulin, Shc was found to associate with GRB2. These results demonstrate that after stimulation of rat tissues with insulin, Shc binds to the insulin receptor, is tyrosine-phosphorylated, and subsequently associated with GRB2.

Malnutrition is related to diabetes in tropical countries. In experimental animals, protein deficiency may affect insulin secretion. However, the effect of malnutrition on insulin receptor phosphorylation and further intracellular signaling events is not known. Therefore, we decided to evaluate the rate of insulin secretion and the early molecular steps of insulin action in insulin-sensitive tissues of an animal model of protein deficiency. Pancreatic islets isolated from rats fed a standard (17%) or a low (6%) protein diet were studied for their secretory response to increasing concentrations of glucose in the culture medium. Basal as well as maximal rates of insulin secretion were significantly lower in the islets isolated from rats fed a low protein diet. Moreover, the dose-response curve to glucose was significantly shifted to the right in the islets from malnourished rats compared with islets from control rats. During an oral glucose tolerance test, there were significantly lower circulating concentrations of insulin in the serum of rats fed a low protein diet in spite of no difference in serum glucose concentration between the groups, suggesting an increased peripheral insulin sensitivity. Immunoblotting and immunoprecipitation were used to study the phosphorylation of the insulin receptor and the insulin receptor substrate-1 as well as the insulin receptor substrate-1-p85 subunit of phosphatidylinositol 3-kinase association in response to insulin. Values were greater in hind-limb muscle from rats fed a low protein diet compared with controls. No differences were detected in the total amount of protein corresponding to the insulin receptor or insulin receptor substrate-1 between muscle from rats fed the two diets. Therefore, we conclude that a decreased glucose-induced insulin secretion in pancreatic islets from protein-malnourished rats is responsible, at least in part, for an increased phosphorylation of the insulin receptor, insulin receptor substrate-1 and its association with phosphatidylinositol 3-kinase. These might represent some of the factors influencing the equilibrium in glucose concentrations observed in animal models of malnutrition and undernourished subjects.

The Janus kinase family of protein tyrosine kinases constitutes a novel type of signal transduction pathway activated in response to a wide variety of polypeptide ligands and has four known members: JAK1, JAK2, JAK3, and Tyk2. In this study, we examined the ability of insulin to stimulate JAK2 tyrosine phosphorylation in insulin-sensitive tissues of the intact rat using immunoprecipitation and immunoblotting. The results demonstrate that after an infusion of insulin, JAK2 is rapidly tyrosine phosphorylated (and the kinase is activated) in the liver, adipose tissue, skeletal muscle, heart, and isolated adipocytes. The presence of phosphorylated JAK2 was detectable after an infusion of insulin that increased serum insulin to physiological postprandial levels (40-70 microunits/ml). Co-immunoprecipitation with anti-insulin receptor antibody, anti-JAK2 antibody, and anti-IRS-1 antibody showed that JAK2 interacts with the insulin receptor and IRS-1 to form stable complexes following stimulation by insulin. In two animal models of insulin resistance the regulation of JAK2 tyrosine phosphorylation after insulin infusion paralleled the phosphorylation of the insulin receptor and of IRS-1. In conclusion, our data indicate that after physiological stimulation by insulin in the intact animal, JAK2 associates with the insulin receptor and is tyrosine phosphorylated in insulin-sensitive tissues in a time- and dose-dependent fashion.

The presence of tyrosine-phosphorylated proteins was studied in cultured rat pancreatic islets. Immunoblotting performed with total extracts of islets cultured in the presence of 1.8 or 5.6 mM glucose revealed at least three distinct tyrosine-phosphorylated bands (25 kDa, 95 kDa and 165-185 kDa). After 12 h incubation in medium containing 1.8 mM glucose, a pulse exposition to 11 or 22 mM glucose or to 10(-7) M insulin led to a substantial increase in the phosphorylation of all three bands, with no appearance of novel bands. Immunoprecipitation with specific antibodies demonstrated that the signal detected at 95 kDa corresponds to the beta subunit of the insulin receptor (IR) while the band at 165-185 kDa corresponds to the early substrates of the insulin receptor, IRS-1 and IRS-2. Immunoprecipitation with IRS-1 or IRS-2 antisera detected their association with the lipid metabolizing enzyme phosphatidylinositol 3-kinase (PI 3-kinase). Thus, this is the first demonstration that elements involved in the insulin-signalling pathway of traditional target tissues are also present in pancreatic islets and are potentially involved in auto- and paracrine-signalling in this organ.

Rat pancreatic islets exposed to interleukin-1 beta (IL-1 beta) in the presence of succinic acid monomethyl ester (SAM) have a higher insulin release in response to glucose and higher glucose oxidation rates, as compared to islets exposed to IL-1 beta alone. These beneficial effects of SAM were not accompanied by any decrease in IL-1 beta-induced nitric oxide (NO) production nor inhibition of aconitase activity. Moreover, SAM did not increase biosynthesis of glutamate decarboxylase. SAM apparently improves beta-cell function mostly by increasing the capacity of these cells to endure NO exposure and partial blockage of the Krebs cycle.

A 19-years-old female with a primary right atrial angiosarcoma partially obstructing the tricuspid valve, developed severe hypoxemia due to right-to-left shunting through a patient foramen ovale. This is the first report of such clinical situation with this type of tumor. A complete resection of the tumor was attempted, and the right atrium had to be rebuilt with a bovine pericardium patch. Post-operative cranial, thoracic and abdominal CT scans and bone scintigraphy did not show metastatic spread. Chest radiation therapy was started on the third postoperative week. Chemotherapy was not used. The patient died five months after surgery due to disseminated metastatic disease but no evidence of the tumor was found in the necroscopic study of the heart.

Purpose: To evaluate the incidence of severe protein-calorie malnutrition in patients with dilated cardiomyopathy (DC), and its correlation with left ventricular contractility., Methods: Group A--51 patients with DC in decompensated congestive heart failure class III or IV, 36 men, aged 51.9 +/- 15.6 years. Group B--25 patients admitted for elective myocardial revascularization with normal LV contractility, 20 men, aged 57.2 +/- 10.5 years. Tricipital skinfold thickness (TS) and mid-arm muscle circumference (MAMC) were obtained in all patients. Severe protein-calorie malnutrition was defined when both measurements were below the fifth populational percentile (Frisancho tables). In Group Am the echocardiographic left ventricular (LV) diastolic diameter (DD), ejection fraction (EF) and systolic volume (SV) were obtained. Those LV parameters were compared between DC patients with and without severe malnutrition. Correlation analysis were performed between TS, MAMC and LV DD, EF, and SV, in the patients of Group A., Results: Severe malnutrition occurred in 7/51 (13.7%) of Group A, and none in Group B. TS values were of 8.90 +/- 4.47 cm in Gr. A and 23.48 +/- 8.52 in B (p < 0.001). MAMC measured 22.25 +/- 3.13 cm in Gr. A and 23.58 +/- 8.52 in B (p = 0.03), LVEF was of 36.29 +/- 9.43% in severe malnutrition patients and of 37.84 +/- 9.78 in the other patients of Group A (p = 0.70). Conversely, LVDD was of 70.90 +/- 11.3 mm vs. 70.75 +/- 8.54 mm (p = 0.98), and LVSV was of 113.0 +/- 52.7 ml vs. 137.6 +/- 56.8 (p = 0.45), when compared severe malnutrition with the rest of patients of Group A. No correlation was found between TS and MAMC and LV, EF, DD and SV in Group A., Conclusion: Severe malnutrition was frequent in patients with DC and heart failure. TS measurements, reflecting caloric reserves, were more affected. Echocardiographic parameters of LV function did not correlate with nutritional status.

A 56 year old woman with a previously normal heart developed severe left ventricular dilation and hypo-contractility after a few weeks of a refractory, high ventricular rate atrial fibrillation. Reduction of heart rate with verapamil resulted in a rapid normalization of myocardial contractility.

Purpose: To study the consequences of a diet with usual salt quantity (non salt-restricted) on hospital treatment of congestive heart failure (CHF), in behalf of a better food intake., Methods: Thirty-two patients admitted to compensation of class III or IV CHF, randomly allowed to group I (2 g salt per day diet) or II (10 g salt). Hypertensive, renal failure or restrictive syndrome cases were excluded. Oral medication and water intake were standardized; furosemide dosage was adjusted on a daly basis, allowing the study of this drug's requirements in each group. Compensation of CHF was defined as a return to classes I or II without edema., Results: Group I included 14 and group II 18 patients. There was no significant difference between groups respective to the time needed for compensation of CHF (7.5 x 6.6 days, mean) percentual weight loss (12.2 x 10.0%), cumulative furosemide dosage (568 x 599 mg), mean daily furosemide dosage per kilogram of lean weight (1.43 x 1.58 mg/kg/day), and to 24-hour urinary excretion of sodium (241 x 254 mEq) and potassium (38.8 x 53.9 mEq). Small elevations of blood urea and potassium were an uniform trend. There was no significant alteration of plasmatic sodium. Food intake was adequate. There was one death for each group, from causes not directly related to CHF., Conclusion: Dietary salt intake did not adversely influence in-hospital compensation of severe CHF in studied group. In selected cases, adoption of a more liberal diet in this aspect may allow the patient a better ingestion of food.

Purpose: To study the clinical features of a group of patients with fatal acute rheumatic fever (ARF)., Patients and Methods: Thirteen patients with ARF, the ages ranged between 4.5 and 25 (mean 14) years. Eight patients were male. Patients were studied in two groups: group A of those 14 year-old or younger (8 cases), and group B of those older than 15 years (5 cases)., Results: Clinical presentation was fever and severe heart failure in all patients. In group A, it was the first attack of ARF in 5 patients. The time elapsed between beginning of symptoms and hospital admission ranged between 10 and 90 (mean 40) days. Mitral insufficiency occurred in all patients. The blood leukocyte count was greater than 10000 per mm3 in six cases. Atrioventricular block occurred in one case. Valvular vegetations were detected on echocardiogram in 4 cases. Two patients received antibiotic therapy. Surgical treatment of the valvular heart disease was carried on in one patient. In group B, it was the first ARF attack in 2 cases, the time elapsed between beginning of the symptoms and hospital admission ranged between 4 and 60 (mean 21) days. Leukocyte count greater than 10000 por mm3 occurred in 4 cases. Atrioventricular block was diagnosed in one case. Valvular vegetations on echocardiogram were detected in 2 patients. In two cases, the treatment was antibiotic therapy. Three patients were operated on., Conclusion: ARF may still be fatal, even in the first attack or in patients in the third decade of life. Other diagnoses are frequently considered, due to the intense clinical and laboratorial manifestations.

A man with chronic alcoholism presenting with recent-onset congestive heart failure and hyperdynamic features. Low arteriovenous oxygen content difference suggested high cardiac output. After 10 days of alcohol withdrawal, rest and balanced feeding the patient was asymptomatic and cardiomegaly subsided. No supplementation of thiamine was required.