Dietary phosphate restriction prevents the appearance of sarcopenia signs in old mice

BACKGROUND

Sarcopenia is defined by the progressive and generalized loss of muscle mass and function associated with aging. We have previously proposed that aging-related hyperphosphataemia is linked with the appearance of sarcopenia signs. Because there are not effective treatments to prevent sarcopenia, except for resistance exercise, we propose here to analyse whether the dietary restriction of phosphate could be a useful strategy to improve muscle function and structure in an animal model of aging.

METHODS

Five-month-old (young), 24-month-old (old) and 28-month-old (geriatric) male C57BL6 mice were used. Old and geriatric mice were divided into two groups, one fed with a standard diet (0.6% phosphate) and the other fed with a low-phosphate (low-P) diet (0.2% phosphate) for 3 or 7 months, respectively. A phosphate binder, Velphoro®, was also supplemented in a group of old mice, mixed with a standard milled diet for 3 months. Muscle mass was measured by the weight of gastrocnemius and tibial muscles, and quality by nuclear magnetic resonance imaging (NMRI) and histological staining assays. Muscle strength was measured by grip test and contractile properties of the tibialis muscle by electrical stimulation of the common peroneal nerve. Gait parameters were analysed during the spontaneous locomotion of the mice with footprinting. Orientation and motor coordination were evaluated using a static rod test.

RESULTS

Old mice fed with low-P diet showed reduced serum phosphate concentration (16.46 ± 0.77 mg/dL young; 21.24 ± 0.95 mg/dL old; 17.46 ± 0.82 mg/dL low-P diet). Old mice fed with low-P diet displayed 44% more mass in gastrocnemius muscles with respect to old mice (P = 0.004). NMRI revealed a significant reduction in T2 relaxation time (P = 0.014) and increased magnetization transfer (P = 0.045) and mean diffusivity (P = 0.045) in low-P diet-treated mice compared with their coetaneous. The hypophosphataemic diet increased the fibre size and reduced the fibrotic area by 52% in gastrocnemius muscle with respect to old mice (P = 0.002). Twitch force and tetanic force were significantly increased in old mice fed with the hypophosphataemic diet (P = 0.004 and P = 0.014, respectively). Physical performance was also improved, increasing gait speed by 30% (P = 0.032) and reducing transition time in the static rod by 55% (P = 0.012). Similar results were found when diet was supplemented with Velphoro®.

CONCLUSIONS

The dietary restriction of phosphate in old mice improves muscle quantity and quality, muscle strength and physical performance. Similar results were found using the phosphate binder Velphoro®, supporting the role of phosphate in the impairment of muscle structure and function that occurs during aging.

Towards a smoke-free world? South America became the first 100% smoke-free subregion in the Americas

Almost 20 years after the launching by the Pan American Health Organization of its “Smoke-Free Americas” initiative in 2001, in December 2020, South America became the first subregion in the Americas to accomplish 100% smoke-free environments in line with Article 8 of the World Health Organization Framework Convention on Tobacco Control (FCTC). Some of these countries adopted legal measures that are more robust than others, including in their laws specific outdoor places in the smoking ban (like Argentina and Uruguay) and/or novel nicotine and tobacco products under their scope (like Ecuador and Paraguay). The 10 countries took different paths to adopt this public health measure, either through executive or legislative measures or a combination of both. A few countries, like Argentina, Brazil, and Venezuela, started at the subnational level and then moved on to the national level, similar to the rest of the countries.

For achieving this milestone, an adequate context was crucial: the broad ratification of the FCTC and the relevance given to the human right to health, civil society efforts, commitments made by intergovernmental bodies, media and communication strategies, and the development of scientific evidence. Countries faced obstacles, including the well-known interference of the tobacco industry, which among other strategies used litigation; however, courts and judges upheld comprehensive legal measures on smoke-free environments.

The process by which South America achieved this milestone represents a role model for other subregions of the Americas and the world.

Effect of Physical Activity/Exercise on Oxidative Stress and Inflammation in Muscle and Vascular Aging

Functional status is considered the main determinant of healthy aging. Impairment in skeletal muscle and the cardiovascular system, two interrelated systems, results in compromised functional status in aging. Increased oxidative stress and inflammation in older subjects constitute the background for skeletal muscle and cardiovascular system alterations. Aged skeletal muscle mass and strength impairment is related to anabolic resistance, mitochondrial dysfunction, increased oxidative stress and inflammation as well as a reduced antioxidant response and myokine profile. Arterial stiffness and endothelial function stand out as the main cardiovascular alterations related to aging, where increased systemic and vascular oxidative stress and inflammation play a key role. Physical activity and exercise training arise as modifiable determinants of functional outcomes in older persons. Exercise enhances antioxidant response, decreases age-related oxidative stress and pro-inflammatory signals, and promotes the activation of anabolic and mitochondrial biogenesis pathways in skeletal muscle. Additionally, exercise improves endothelial function and arterial stiffness by reducing inflammatory and oxidative damage signaling in vascular tissue together with an increase in antioxidant enzymes and nitric oxide availability, globally promoting functional performance and healthy aging. This review focuses on the role of oxidative stress and inflammation in aged musculoskeletal and vascular systems and how physical activity/exercise influences functional status in the elderly.

MO414: Sucroferric Oxyhydroxide (Velphoro®) Treatment Mitigates the Signs of Ageing-Related Sarcopaenia in Old Mice

BACKGROUND AND AIMS

Sarcopaenia, defined as the loss of muscle mass and function, is an ageing-related pathology associated with some important diseases such as chronic kidney disease (CKD). Hyperphosphatemia has been associated with both, ageing and CKD. Old mice show an increase in serum phosphate concentration and a reduction in muscle mass, forelimb strength, gait speed and transition time in the static bar, with respect to young mice. Previous results of our group showed the beneficial effects of a low phosphate diet on ageing-related sarcopaenia. Given that the implementation of dietary phosphate restriction entails difficulties in the elderly, the aim of this work was to analyse the beneficial effects of a diet supplemented with a phosphate binder on the signs of sarcopaenia.

METHOD

C57BL6 male mice were used for in vivo studies: 5-month-old (young) and 24-month-old (old), which were fed with a powder standard diet (containing 0.6% of phosphate). Some old mice were fed with a hypophosphatemic diet (containing 0.2% of phosphate) or with a diet supplemented with 5% sucroferric oxyhydroxide (Velphoro®) for the last 3 months before sacrifice. Serum phosphate levels were analysed with a commercial kit. Muscle mass was estimated by measuring the gastrocnemius muscle mass divided by total body mass, muscle force was measured by a grip test and physical performance was evaluated by a gait test and the static bar test.

RESULTS

Velphoro® treated old mice showed a significant and more effective reduction in phosphate serum levels than old mice fed with the hypophosphatemic diet. No differences were observed in the relative gastrocnemius muscle mass between the three old mice experimental groups. By contrast, old mice fed with the standard diet supplemented with Velphoro® displayed an increased muscular strength and physical performance, improving the gait speed and reducing the transition time in the static bar, compared with old mice fed with the standard diet. Results obtained with Velphoro® treatment were similar to those observed in old mice fed with the hyphophosphatemic diet, but Velphoro® treatment achieve better results in motor coordination in the static bar test.

CONCLUSION

Dietary restriction of phosphate is a useful approach to mitigate the signs of ageing-related sarcopaenia (muscle strength and physical performance) in old mice. The use of Velphoro®, as a phosphate binder, exhibits similar or even better results than the hypophosphatemic diet. Therefore, the administration of Velphoro® could attenuate the signs of sarcopaenia in the elderly or in ageing-related diseases in which sarcopaenia is common, like CKD.

Aging-related hyperphosphatemia impairs myogenic differentiation and enhances fibrosis in skeletal muscle

BACKGROUND

Hyperphosphatemia has been related to the development of sarcopenia in aging mice. We describe the intracellular mechanisms involved in the impairment of the myogenic differentiation promoted by hyperphosphatemia and analyse these mechanisms in the muscle from older mice.

METHODS

C₂ C₁₂ cells were grown in 2% horse serum in order to promote myogenic differentiation, in the presence or absence of 10 mM beta-glycerophosphate (BGP) for 7 days. Troponin T, paired box 7 (Pax-7), myogenic factor 5 (Myf5), myogenic differentiation 1 (MyoD), myogenin (MyoG), myocyte enhancer factor 2 (MEF2C), P300/CBP-associated factor (PCAF), histone deacetylase 1 (HDAC1), fibronectin, vimentin, and collagen I were analysed at 48, 72, and 168 h, by western blotting or by immunofluorescence staining visualized by confocal microscopy. Studies in mice were performed in 5- and 24-month-old C57BL6 mice. Three months before sacrifice, 21-month-old mice were fed with a standard diet or a low phosphate diet, containing 0.6% or 0.2% phosphate, respectively. Serum phosphate concentration was assessed by a colorimetric method and forelimb strength by a grip test. Fibrosis was observed in the tibialis anterior muscle by Sirius Red staining. In gastrocnemius muscle, MyoG, MEF2C, and fibronectin expressions were analysed by western blotting.

RESULTS

Cells differentiated in the presence of BGP showed near five times less expression of troponin T and kept higher levels of Pax-7 than control cells indicating a reduced myogenic differentiation. BGP reduced Myf5 about 50% and diminished MyoD transcriptional activity by increasing the expression of HDAC1 and reducing the expression of PCAF. Consequently, BGP reduced to 50% the expression of MyoG and MEF2C. A significant increase in the expression of fibrosis markers as collagen I, vimentin, and fibronectin was found in cells treated with BGP. In mice, serum phosphate (17.24 ± 0.77 mg/dL young; 23.23 ± 0.81 mg/dL old; 19.09 ± 0.75 mg/dL old with low phosphate diet) correlates negatively (r = -0.515, P = 0.001) with the muscular strength (3.13 ± 0.07 gf/g young; 1.70 ± 0.12 gf/g old; 2.10 ± 0.09 gf/g old with low phosphate diet) and with the expression of MyoG (r = -0.535, P = 0.007) and positively with the expression of fibronectin (r = 0.503, P = 0.001) in gastrocnemius muscle. The tibialis anterior muscle from old mice showed muscular fibrosis. Older mice fed with a low phosphate diet showed improved muscular parameters relative to control mice of similar age.

CONCLUSIONS

Hyperphosphatemia impairs myogenic differentiation, by inhibiting the transcriptional activity of MyoD, and enhances the expression of fibrotic genes in cultured myoblasts. Experiments carried out in older mice demonstrate a close relationship between age-related hyperphosphatemia and the decrease in the expression of myogenic factors and the increase in factors related to muscle fibrosis.

[Clinical guidelines for the managment of intestinal failure secondary to pediatric short bowel syndrome]

Intestinal failure secondary to short bowel syndrome in pediatrics, is a rare condition with high morbimortality. A follow up multidisciplinary team is necessary to minimize complications and optimize the intestinal rehabilitation. There are no gold standard guidelines for the management of this group of complex patients. The development of clinical guidelines may contribute for an adequate management of patients with intestinal failure and short bowel syndrome. This Clinical Guideline for the Management was developed by 16 experts based on modified Delphi methodology. The meetings were held at the Argentinian Association of Enteral and Parenteral Nutrition (Asociación Argentina de Nutrición Enteral y Parenteral); the topics analyzed were definitions, epidemiology, enteral and parenteral nutrition, pharmacological and surgical treatments, and criteria for referring patients to intestinal rehabilitation centers. The document is aimed to provide basic scientific knowledge for medical institutions, health providers, healthcare providers, patients and families.

Hyperphosphatemia-Induced Oxidant/Antioxidant Imbalance Impairs Vascular Relaxation and Induces Inflammation and Fibrosis in Old Mice

Aging impairs vascular function, but the mechanisms involved are unknown. The aim of this study was to analyze whether aging-related hyperphosphatemia is implied in this effect by elucidating the role of oxidative stress. C57BL6 mice that were aged 5 months (young) and 24 months (old), receiving a standard (0.6%) or low-phosphate (0.2%) diet, were used. Isolated mesenteric arteries from old mice showed diminished endothelium-dependent vascular relaxation by the down-regulation of NOS3 expression, increased inflammation and increased fibrosis in isolated aortas, compared to those isolated from young mice. In parallel, increased Nox4 expression and reduced Nrf2, Sod2-Mn and Gpx1 were found in the aortas from old mice, resulting in oxidant/antioxidant imbalance. The low-phosphate diet improved vascular function and oxidant/antioxidant balance in old mice. Mechanisms were analyzed in endothelial (EC) and vascular smooth muscle cells (SMCs) treated with the phosphate donor ß-glycerophosphate (BGP). In EC, BGP increased Nox4 expression and ROS production, which reduced NOS3 expression via NFκB. BGP also increased inflammation in EC. In SMC, BGP increased Collagen I and fibronectin expression by priming ROS production and NFκB activity. In conclusion, hyperphosphatemia reduced endothelium-dependent vascular relaxation and increased inflammation and vascular fibrosis through an impairment of oxidant/antioxidant balance in old mice. A low-phosphate diet achieved improvements in the vascular function in old mice.

Gut ecosystem during infancy: The role of "biotics"

In recent years, the evidence has demonstrated the relevance of the gut microbiota in an individual's health. The dynamics of an early colonization and the establishment of a community of plenty, diverse, and healthy microorganisms from a vaginal delivery and breastfeeding are critical for the development of a healthy immune matrix. The objective of this review is to describe the available evidence on microbiota development in the first year of life and the current possibilities offered by prebiotics, probiotics, symbiotics, and postbiotics during such critical stage of life.

Uraemic toxins impair skeletal muscle regeneration by inhibiting myoblast proliferation, reducing myogenic differentiation, and promoting muscular fibrosis

Uraemic toxins increase in serum parallel to a decline in the glomerular filtration rate and the development of sarcopenia in patients with chronic kidney disease (CKD). This study analyses the role of uraemic toxins in sarcopenia at different stages of CKD, evaluating changes in the muscular regeneration process. Cultured C₂C₁₂ cells were incubated with a combination of indoxyl sulphate and p-cresol at high doses (100 µg/mL) or low doses (25 µg/mL and 10 µg/mL) resembling late or early CKD stages, respectively. Cell proliferation (analysed by scratch assays and flow cytometry) was inhibited only by high doses of uraemic toxins, which inactivated the cdc2-cyclin B complex, inhibiting mitosis and inducing apoptosis (analysed by annexin V staining). By contrast, low doses of uraemic toxins did not affect proliferation, but reduced myogenic differentiation, primed with 2% horse serum, by inhibiting myogenin expression and promoting fibro-adipogenic differentiation. Finally, to assess the in vivo relevance of these results, studies were performed in gastrocnemii from uraemic rats, which showed higher collagen expression and lower myosin heavy chain expression than those from healthy rats. In conclusion, uraemic toxins impair the skeletal muscular regeneration process, even at low concentrations, suggesting that sarcopenia can progress from the early stages of CKD.

Regional Alterations in Cortical Sulcal Depth in Living Fetuses with Down Syndrome

Down syndrome (DS) is the most common genetic cause of developmental disabilities. Advanced analysis of brain magnetic resonance imaging (MRI) has been used to find brain abnormalities and their relationship to neurocognitive impairments in children and adolescents with DS. Because genetic factors affect brain development in early fetal life, there is a growing interest in analyzing brains from living fetuses with DS. In this study, we investigated regional sulcal folding depth as well as global cortical gyrification from fetal brain MRIs. Nine fetuses with DS (29.1 ± 4.24 gestational weeks [mean ± standard deviation]) were compared with 17 typically developing [TD] fetuses (28.4 ± 3.44). Fetuses with DS showed lower whole-brain average sulcal depths and gyrification index than TD fetuses. Significant decreases in sulcal depth were found in bilateral Sylvian fissures and right central and parieto-occipital sulci. On the other hand, significantly increased sulcal depth was shown in the left superior temporal sulcus, which is related to atypical hemispheric asymmetry of cortical folding. Moreover, these group differences increased as gestation progressed. This study demonstrates that regional sulcal depth is a sensitive marker for detecting alterations of cortical development in DS during fetal life, which may be associated with later neurocognitive impairment.

A Latin American and Spanish pediatric gastroenterology group's understanding of cow's milk protein allergy diagnosis and treatment: Results of a survey by the Food Allergy Working Group of the Sociedad Latinoamericana de Gastroenterología, Hepatología y Nutrición Pediátrica

INTRODUCTION

There are discrepancies in the diagnosis and management of cow's milk protein allergy (CMPA) in Spain and Latin America. The aim of the present study was to find out how Spanish and Latin American pediatric gastroenterologists diagnose and treat CMPA.

MATERIAL AND METHODS

Pediatric gastroenterologists, members of the Sociedad Latinoamericana de Gastroenterología, Hepatología y Nutrición, were invited to fill out a structured survey, the results of which were then compared with the 2012 and 2014 diagnosis and treatment guidelines, respectively.

RESULTS

The survey results showed that 17% of the participants follow the diagnostic recommendations based on the published consensus and guidelines. To diagnose non-IgE-mediated CMPA, 15% of the participants utilize IgE-specific skin prick tests, 22% use IgE-specific blood tests, and 45% employ oral food challenges. To diagnose IgE-mediated CMPA the percentages for the same diagnostic methods were 57, 83 and 22%, respectively. Once diagnosis is confirmed, 98% of the participants provide dietary recommendations. In children that are not breastfed, 89% of the participants prescribe an initial extensively hydrolyzed formula, 9% an amino acid formula, 1% a soy formula, and 1% a hydrolyzed rice formula. In patients with IgE-mediated CMPA, 34% of the participants carry out an oral challenge once treatment is completed, 39% according to symptom severity, and 27% in relation to IgE-specific testing.

CONCLUSION

CMPA management is diverse and there is poor adherence to the clinical practice guidelines.

Endothelin-1 induces cellular senescence and fibrosis in cultured myoblasts. A potential mechanism of aging-related sarcopenia

Endothelial dysfunction, with increased endothelin-1 (ET-1) synthesis, and sarcopenia, characterized by the loss of muscular mass and strength, are two aging–related conditions. However, a relationship between them has not been already established. The aim of this study was to determine whether ET-1 induces senescence and fibrosis in cultured murine myoblasts, which could be involved in the development of sarcopenia related to aging. For this purpose, myoblasts were incubated with ET-1 to assess cellular senescence, analyzed by senescence associated β-galactosidase activity and p16 expression; and fibrosis, assessed by fibronectin expression. ET-1 induced myoblast senescence and fibrosis through ET_A receptor. The use of antioxidants and several antagonists revealed that ET-1 effect on senescence and fibrosis depended on ROS production and activation of PI₃K-AKT-GSK pathway. To stress the in vivo relevance of these results, circulating ET-1, muscular strength, muscular fibrosis and p16 expression were measured in male C57Bl6 mice from 5-18-24-months-old. Old mice shown high levels of ET-1 correlated with muscular fibrosis, muscular p16 expression and loss of muscle strength. In conclusion, ET-1 promotes fibrosis and senescence in cultured myoblasts, similar results were found in old mice, suggesting a potential role for ET-1 in the development of sarcopenia related to aging.

P0913HYPERPHOSPHATEMIA INCREASE INFLAMMATION PROMOTING SENESCENCE AND MUSCLE DYSFUNCTION

Background and Aims

Hyperphosphatemia has been associated with aging and chronic kidney disease (CKD). Sarcopenia, which is a related condition of these pathologies, is defined by loss of force and muscular mass. During aging, chronic systemic inflammation appears, termed inflammaging, due to changes in immune system function. Inflammaging has been associated with many age-related diseases including Sarcopenia and CKD. The work aimed to evaluate the effect of hyperphosphatemia on proinflammatory profile of cultured myoblast cells and to analyze, in old mice, the effect of a dietary restriction in the phosphate intake on the aging-related sarcopenia.

Methods

Culture murine myoblast C2C12 cells were used for in vitro experiments. Cells were treated with 10 mM beta-glycerophosphate (BGP) as phosphate donor for 24, 48 or 72h. Inflammation was assessed through IL6, TNFα and MCP-1 expression by RT-qPCR. Twenty-four months old, C57BL6 mice were used for in vivo studies. Mice were fed with a normal diet containing 0.6% of phosphate until 21 months, after that, one group of mice continued with a normal diet and the other group was fed with a hypophosphatemic diet, containing a 0.2% of phosphate, for the following 3 months. Old mice were compared with 5 months old mice. Muscle force was measured by a grip strength test. Serum phosphate concentration was evaluated with a commercial kit and inflammation was assessed through IL-1β expression levels by RT-qPCR.

Results

Results showed that BGP treatment augmented pro-inflammatory cytokines levels, in myoblast, at 72h. On the other hand, old mice had a 40% increase in serum phosphate concentration regarding young mice, and, in parallel, they showed a reduction in forelimb strength. Old animals feeding with a hypophosphatemic diet showed a decreased level of phosphate serum linked to a better muscle function. Pro-inflammatory cytokines expression was higher in old mice compared to young mice; those values were reduced in 24-month-mice fed with a low phosphate diet. Furthermore, there was a positive correlation between IL-1β expression levels and serum phosphate levels, suggesting that high levels of serum phosphate were increasing inflammation in vivo and a negative correlation between IL-1β and grip strength test, which shows that high levels of inflammation decrease muscular function

Conclusion

In this work, we propose that high levels of phosphate are related to inflammation in vitro and in vivo. This increase of proinflammatory cytokines decreases muscle function whereas dietary restriction of phosphate decreases inflammation and improves muscle function. These results could point to a direct link between elevated serum phosphate levels and inflammaging presented in sarcopenic people such as CKD patients and aged people.

P0707UREMIC TOXINS IMPAIR SKELETAL MUSCLE REGENERATION PROCESS INDUCING CELL CYCLE ARREST AND APOPTOSIS IN CULTURED MYOBLASTS

Background and Aims

The loss of muscle mass and function has been related to chronic kidney disease (CKD). About 37% of dialysis patients show symptoms of sarcopenia and this has been related to an increased risk of mortality. Changes in sarcopenic muscle include the loss of its regenerative capacity due to a reduction in the number and function of satellite cells, the muscle stem cells. The concentration of serum uremic toxins (UT) increases in parallel to a decline in the glomerular filtration rate in patients with CKD and this uremia may be involved in the development of sarcopenia. Previous studies showed as serum concentration of UT found in the early stages of CKD inhibits myogenic differentiation of cultured myoblasts. Nevertheless, the effect of those concentrations found in the advanced stages of CKD has not been described. The study aimed to analyse whether UT affect the muscular regeneration process by modifying the proliferation capacity of myoblasts (activated satellite cells).

Method

Cultured mouse myoblasts C2C12 cells were used for all experiments. Cells were grown with 0% or 10% FBS culture media in the presence or absence of indoxyl sulphate and para-cresol at doses of 100µg/ml each one, which are similar to ones found in the advanced stages of CKD. Proliferation was evaluated by scratch wound healing and cell cycle by flow cytometry with propidium iodide and the fluorescent probe CFSE, an intracellular protein binding dye that is divided equally between daughter cells, allowing the discrimination of successive rounds of cell division. Chromosome condensation was assessed by immunofluorescence staining by confocal microscopy. Apoptosis was analysed by annexin V staining.

Results

C2C12 cells treated with UT shown a significant decrease in the proliferation rate. A significant delay in wound closure was observed in cells treated with UT compared to control cells. Myoblasts treated with UT suffered a significant decrease in the proliferation rate since the probe remained higher than in the vehicle-treated cells. Proliferating cells treated with UT suffered a dramatic cell cycle arrest between the phases S and G2/M. Chromosome condensation was also analysed, finding that in the presence of colcemid, vehicle-treated cells condensed their chromosomes, as expected, whereas UT-treated cells did not, suggesting that UT stop the cell cycle at any point before the entry of cells in the mitosis phase. Besides, there was strong phosphorylation of cdc2 in the presence of UT indicating that cdc2 and the complex cdc2-cyclin B were inactive. This result explains why cells did not enter in the mitosis phase under UT exposition. Finally, UT induced the death of proliferating C2C12 cells by apoptosis.

Conclusion

In the advanced stages of CKD, uremic toxins concentration increases, thereby inducing a dramatic arrest in the cell cycle of myoblasts, inactivating the cdc2-cyclin B complex, interrupting their proliferation and leading them towards cell apoptosis. These results point to a role of uremic toxins impairing the skeletal muscle regeneration process, which could be involved in CKD-related sarcopenia and frailty.

P0726ENDOTHELIAL DYSFUNCTION ASSOCIATED TO ATHEROSCLEROSIS OF KNOCKOUT APOE MICE COULD BE MEDIATED BY VASCULAR FIBROSIS

Background and Aims

Patients with chronic kidney disease (CKD) present a high rate of cardiovascular mortality mainly associated with endothelial dysfunction, which causes more cardiovascular events in presence of atherosclerosis. Atherosclerosis is characterized by a significant increase of low density lipoproteins (LDL), reactive oxygen species (ROS) and inflammation. ROS can oxidize LDL generating oxidized-LDL (oxLDL) that promotes the development of cardiovascular pathologies. The aim of this study was to evaluate whether oxLDL induce endothelial dysfunction analysing the involvement of vascular fibrosis.

Method

The model used for in vivo studies was the Knockout apolipoprotein E (KO-apoE) mice, which resemble human atherosclerosis and shown high levels of cholesterol (LDL) that can be oxidized to oxLDL. In mice, blood pressure was registered before sacrificed them. After that, we measured different parameters as serum cholesterol levels, vascular function by vascular reactivity in mesenteric arteries and vascular fibrosis in aorta by Sirius Red staining and by the protein expression of fibronectin and collagen-I by immunohistochemistry. In order to investigate the mechanism of action of oxLDL, in vitro studios were performed on human smooth muscle cells (SMC) incubated with oxLDL at different times. Fibrosis was evaluated by the expression of TGF- β and extracellular matrix proteins such as fibronectin and collagen-I by Western blot and by immunofluorescence. ROS production was also measured by fluorescence confocal microscopy, using the CellROX Deep Red probe.

Results

KO-apoE mice shown higher levels of serum cholesterol and blood pressure than WT animals. Moreover, KO-apoE mice showed endothelial dysfunction since their arteries were less relaxed and more contracted. In addition, these mice presented thickening of vascular wall (SMC layer), more fibrosis showing intense Sirius Red staining and less expression of elastin, all compatible with their vascular dysfunction compared to WT mice. Furthermore, aortas from KO-apoE mice showed a slight increase in fibronectin and collagen-I expression assessed by immunohistochemistry. In vivo studies were confirmed in vitro after treating SMC with oxLDL. oxLDL induced fibrosis in SMC by increasing TGF-β, fibronectin and collagen-I protein expressions evaluated by Western blot and immunofluorescence assays. Treatment with oxLDL also increased ROS production, which seem to be responsible of oxLDL-induced fibrosis in human SMC, as it was blocked in the presence of the antioxidant N-Acetyl-cysteine.

Conclusion

In summary, these results point to endothelial dysfunction associated to atherosclerosis (oxLDL) could be mediated by an increase in the development of vascular fibrosis where ROS could play an important role. Therefore, the endothelial dysfunction typical of CKD patients could impair with more vascular fibrosis when atherosclerosis is also present.

Hyperphosphatemia Promotes Senescence of Myoblasts by Impairing Autophagy Through Ilk Overexpression, A Possible Mechanism Involved in Sarcopenia

In mammalians, advancing age is associated with sarcopenia, the progressive and involuntary loss of muscle mass and strength. Hyperphosphatemia is an aging-related condition involved in several pathologies. The aim of this work was to assess whether hyperphosphatemia plays a role in the age-related loss of mass muscle and strength by inducing cellular senescence in murine myoblasts and to explore the intracellular mechanism involved in this effect. Cultured mouse C2C12 cells were treated with 10 mM beta-glycerophosphate (BGP] at different periods of time to induce hyperphosphatemia. BGP promoted cellular senescence after 24 h of treatment, assessed by the increased expression of p53, acetylated-p53 and p21 and senescence associated β-galactosidase activity. In parallel, BGP increased ILK expression and activity, followed by mTOR activation and autophagy reduction. Knocking-down ILK expression increased autophagy and protected cells from senescence induced by hyperphosphatemia. BGP also reduced the proliferative capacity of cultured myoblasts. Old mice (24-months-old] presented higher serum phosphate concentration, lower forelimb strength, higher expression of p53 and ILK and less autophagy in vastus muscle than young mice (5-months-old]. In conclusion, we propose that hyperphosphatemia induces senescence in cultured myoblasts through ILK overexpression, reducing their proliferative capacity, which could be a mechanism involved in the development of sarcopenia, since old mice showed loss of muscular strength correlated with high serum phosphate concentration and increased levels of ILK and p53.

Hyperphosphatemia induces senescence in human endothelial cells by increasing endothelin-1 production

Hyperphosphatemia is related to some pathologies, affecting vascular cell behavior. This work analyzes whether high concentration of extracellular phosphate induces endothelial senescence through up‐regulation of endothelin‐1 (ET‐1), exploring the mechanisms involved. The phosphate donor β‐glycerophosphate (BGP) in human endothelial cells increased ET‐1 production, endothelin‐converting enzyme‐1 (ECE‐1) protein, and mRNA expression, which depend on the AP‐1 activation through ROS production. In parallel, BGP also induced endothelial senescence by increasing p16 expression and the senescence‐associated β‐galactosidase (SA‐ß‐GAL) activity. ET‐1 itself was able to induce endothelial senescence, increasing p16 expression and SA‐ß‐GAL activity. In addition, senescence induced by BGP was blocked when different ET‐1 system antagonists were used. BGP increased ROS production at short times, and the presence of antioxidants prevented the effect of BGP on AP1 activation, ECE‐1 expression, and endothelial senescence. These findings were confirmed in vivo with two animal models in which phosphate serum levels were increased: seven/eight nephrectomized rats as chronic kidney disease models fed on a high phosphate diet and aged mice. Both models showed hyperphosphatemia, higher levels of ET‐1, and up‐regulation in aortic ECE‐1, suggesting a direct relationship between hyperphosphatemia and ET‐1. Present results point to a new and relevant role of hyperphosphatemia on the regulation of ET‐1 system and senescence induction at endothelial level, both in endothelial cells and aorta from two animal models. The mechanism involved showed a higher ROS production, which probably activates AP‐1 transcription factor and, as a result, ECE‐1 expression, increasing ET‐1 synthesis, which in consequence induces endothelial senescence.

The importance of continued engagement during the implementation phase of tobacco control policies in a middle-income country: the case of Costa Rica

OBJECTIVE

To analyse the process of implementing and enforcing smoke-free environments, tobacco advertising, tobacco taxes and health warning labels from Costa Rica's 2012 tobacco control law.

METHOD

Review of tobacco control legislation, newspaper articles and interviewing key informants.

RESULTS

Despite overcoming decades of tobacco industry dominance to win enactment of a strong tobacco control law in March 2012 consistent with WHO's Framework Convention on Tobacco Control, the tobacco industry and their allies lobbied executive branch authorities for exemptions in smoke-free environments to create public confusion, and continued to report in the media that increasing cigarette taxes led to a rise in illicit trade. In response, tobacco control advocates, with technical support from international health groups, helped strengthen tobacco advertising regulations by prohibiting advertising at the point-of-sale (POS) and banning corporate social responsibility campaigns. The Health Ministry used increased tobacco taxes earmarked for tobacco control to help effectively promote and enforce the law, resulting in high compliance for smoke-free environments, advertising restrictions and health warning label (HWL) regulations. Despite this success, government trade concerns allowed, as of December 2015, POS tobacco advertising, and delayed the release of HWL regulations for 15 months.

CONCLUSIONS

The implementation phase continues to be a site of intensive tobacco industry political activity in low and middle-income countries. International support and earmarked tobacco taxes provide important technical and financial assistance to implement tobacco control policies, but more legal expertise is needed to overcome government trade concerns and avoid unnecessary delays in implementation.

[National consensus on the modified Atkins diet]

INTRODUCTION

Epilepsy is a chronic disease that affects 0.5-1% of the population. One third of the patients become refractory to antiepileptic drugs. Among the non-pharmacological treatments available, the modified Atkins diet is an effective treatment used since 2003 as another alternative for children and adults with refractory epilepsy.

DEVELOPMENT

The Ketogenic Diet National Committee, which depends on the Argentine Society of Pediatric Neurology, elaborated this consensus on the modified Atkins diet, basing itself on a review of the literature and on their clinical experience. This consensus in Spanish explains the different aspects to be taken into account regarding the modified Atkins diet, patient selection, implementation, different controls and adverse effects. Unlike the classic ketogenic diet, the modified Atkins diet is initiated without fasting or hospital stay, nor does it require protein, calorie or fluid restriction, thus improving patient palatability and consequently patient tolerability.

CONCLUSIONS

The modified Atkins diet is a useful treatment for patients with intractable epilepsy. The publication of this consensus offers the possibility for new centers to get oriented regarding this diet implementation.

Costa Rica's implementation of the Framework Convention on Tobacco Control: Overcoming decades of industry dominance

OBJECTIVE

To analyze the passage of Costa Rica's 2012 tobacco control law.

MATERIALS AND METHODS

Review of legislation, newspaper articles, and key informant interviews.

RESULTS

Tobacco control advocates, in close collaboration with international health groups, recruited national, regional and international experts to testify in the Legislative Assembly, implemented grassroots advocacy campaigns, and generated media coverage to enact strong legislation in March 2012 consistent with the World Health Organization Framework Convention on Tobacco Control, despite tobacco industry lobbying efforts that for decades blocked effective tobacco control legislation.

CONCLUSION

Costa Rica's experience illustrates how with resources, good strategic planning, aggressive tactics and perseverance tobacco control advocates can overcome tobacco industry opposition in the Legislative Assembly and Executive Branch. This determined approach has positioned Costa Rica to become a regional leader in tobacco control.

Recommendations for the clinical management of children with refractory epilepsy receiving the ketogenic diet

The ketogenic diet, a non-drug treatment with proven effectiveness, has been the most commonly used therapy in the past decade for the management of refractory epilepsy in the pediatric population. Compared to adding a new drug to a pre-existing treatment, the ketogenic diet is highly effective and reduces the number of seizures by 50-90% in approximately 45-60% of children after six months of treatment. For this reason, the Argentine Society of Pediatric Neurology established the Ketogenic Diet Working Group. It is integrated by pediatric dietitians, pediatricians, pediatric neurologists and B.S. in Nutrition, who developed recommendations for the optimal management of patients receiving the classical ketogenic diet based on expert consensus and scientific publications in this field.

[Management of the most frequent functional gastrointestinal dis orders in healthy infants]

Healthy infants during the first year of life often have multiple functional gastrointestinal symptoms such as colic, regurgitation and constipation. The usual fuzziness and/or crying at this stage of life is interpreted as digestive discomfort or pain, and the corresponding concerns result in unsuitable behaviors as overeating, interruption of breastfeeding, multiple changes of formulas, innumerable queries and unnecessary medications. The aim of this paper is to update knowledge on the pathophysiology of the most common functional gastrointestinal dis orders, in order to avoid over diagnosis and select the most appropriate therapeutic approach and convenient nutritional interventions.

[Not Available]

During the last twenty years Eosinophilic Esophagitis has become one the most important causes of esophageal disfunction in children, food impactation in adolescents and young adults, therapeutic failure in patients with gastroesophageal reflux disease (GERD) and the most frecuent eosinophilic disease of the gastrointestinal tract. We present recommendations for the diagnosis and treatment of the disease based in a systematic review of the literature.

[National consensus on the ketogenic diet]

INTRODUCTION

Epilepsy is a chronic disease with onset in infancy affecting 0.5-1% of the population. One third of the patients is refractory to antiepileptic drugs and they pose a challenge for the health care team. The ketogenic diet is an effective, non-pharmacological, alternative treatment for the management of refractory epilepsy.

AIMS

There is a need to establish guidelines for the adequate and increased use of the ketogenic diet in Spanish-speaking countries. The National Committee on the Ketogenic Diet, consisting of paediatric neurologists, clinical nutritionists, and dietitians, of the Argentine Society of Child Neurology has developed this consensus statement to standardize the use of the ketogenic diet based on the literature and clinical experience.

DEVELOPMENT

Patient selection, pre-treatment family counseling, drug interactions, micronutrient supplementation, adverse effects, and discontinuation of the diet are discussed.

CONCLUSIONS

The ketogenic diet is an effective treatment for children with refractory epilepsy. Education and collaboration of the patient and their family is essential. The patient should be managed by an experienced multidisciplinary team using a protocol. The formation of a national multidisciplinary team and the publication of this document provide possibilities for new centers to integrate the ketogenic diet into their treatment options.

[Prebiotics in infant health]

The composition of human milk is the main base for the development of infant formulas concerning its macronutrients and micronutrients contents and bioactive compounds. Technological advances in the composition of human milk have identified a great number of bioactive compounds such as prebiotics which are responsible for immunological protection and the prevention of different pathologies. In order to achieve similar benefits, they are part of the contents of infant formulas.

[Liver transplantation in pediatrics. Nutritional measures]

Malnutrition is a constant in candidates for liver transplant. Because of their particular characteristics, pre-operative nutritional intervention is difficult to apply, so that post-transplant action is necessary. A retrospective study was made, reviewing the clinical records of all the children undergoing liver transplants in 1992 in the "La Paz" Children's Hospital, while they were in the Pediatric Intensive Care Unit. Two groups of patients were established--A and B--respectively of 15 and 7 children, according to whether or not they had received immediate post-transplant TPN. In Group A, a total of 150 days was evaluated, with TPN (x = 10 +/- 8.3). The amino acid solutions used were for liver insufficiency (48.8%), Kidney insufficiency (33.3%) and standard (17.8%). Lipids were administered on 6.3% of days in four patients' nutrition. In 54.5% of interventions, infectious complications occurred due to immune-suppression. Comparison of the two patient groups show significant results: those in Group A had a 3.2 relative risk of suffering infection (certainty interval 1.3-1.8). In terms of time in the ICU, the Group A patients were admitted for an average of 13.4 days (range 2-37) as opposed to the 6.28 days of Group B (range 3-15). Results were significant, with p < 0.05. In terms of evolution, the survival rate in patients receiving TPN was 86.6% against 71.4% in those receiving enteral nutritional (n.s.). Our results show a high rate of survival (86.6%). It is not possible to conclude the extent to which the introduction of TPN influenced post-operative evolution, as there was no consistency in terms of the patients' clinical situation.

[Standard formulas of parenteral nutrition. A study of their use in a general hospital]

The goal of the study was to evaluate the use of parenteral nutrition formulas with standardized g. of nitrogen, carbohydrates and lipids, and to analyze whether the nutritional requirements of the patients treated in our hospital were covered by said formulas or whether it was necessary to change and/or standardize a new formula. To do so, a review was made of 5.646 parental nutrition mixtures prepared in the Pharmacy Service and patterned by the Nutrition Service from April, 1991, to May, 1992, for 308 adult patients. The distribution of the mixtures by services, diagnoses and the frequency of the different standard formulas were studied, comparing standard formula frequency with that of non-standard formulas. Findings showed that 41.9% of nutrition mixtures were patterned in surgery, and the most common diagnosis, cancer, appeared in 24%. Of the mixtures, 67.6% were preestablished formulas, and 32.4% were non-standard formulas. The order of frequency among standard formulas was: basic standard formulas, stress formulas, initial formulas, peripheral formulas, hemodialysis formulas and low-volume formulas. All covered the nutritional needs of a large share of the patients for the different pathologies in which they were indicated. Nevertheless the question of designing a new formula to cover a greater number of situations was raised. Protocolization should take place rationally, to meet the hospital's most frequent pathologies, and effectiveness should be evaluated after tracking and checking each patient.