The Longitudinal Changes in Subcutaneous Abdominal Tissue and Visceral Adipose Tissue Volumetries Are Associated with Iron Status.

Excess iron is known to trigger adipose tissue dysfunction and insulin resistance. Circulating markers of iron status have been associated with obesity and adipose tissue in cross-sectional studies. We aimed to evaluate whether iron status is linked to changes in abdominal adipose tissue longitudinally. Subcutaneous abdominal tissue (SAT) and visceral adipose tissue (VAT) and its quotient (pSAT) were assessed using magnetic resonance imaging (MRI), at baseline and after one year of follow-up, in 131 (79 in follow-up) apparently healthy subjects, with and without obesity. Insulin sensitivity (euglycemic- hyperinsulinemic clamp) and markers of iron status were also evaluated. Baseline serum hepcidin (p = 0.005 and p = 0.002) and ferritin (p = 0.02 and p = 0.01)) were associated with an increase in VAT and SAT over one year in all subjects, while serum transferrin (p = 0.01 and p = 0.03) and total iron-binding capacity (p = 0.02 and p = 0.04) were negatively associated. These associations were mainly observed in women and in subjects without obesity, and were independent of insulin sensitivity. After controlling for age and sex, serum hepcidin was significantly associated with changes in subcutaneous abdominal tissue index (iSAT) (ß = 0.406, p = 0.007) and visceral adipose tissue index (iVAT) (ß = 0.306, p = 0.04), while changes in insulin sensitivity (ß = 0.287, p = 0.03) and fasting triglycerides (ß = -0.285, p = 0.03) were associated with changes in pSAT. These data indicated that serum hepcidin are associated with longitudinal changes in SAT and VAT, independently of insulin sensitivity. This would be the first prospective study evaluating the redistribution of fat according to iron status and chronic inflammation.

Downregulation of peripheral lipopolysaccharide binding protein impacts on perigonadal adipose tissue only in female mice.

BACKGROUND AND AIMS: The sexual dimorphism in fat-mass distribution and circulating leptin and insulin levels is well known, influencing the progression of obesity-associated metabolic disease. Here, we aimed to investigate the possible role of lipopolysaccharide-binding protein (LBP) in this sexual dimorphism. METHODS: The relationship between plasma LBP and fat mass was evaluated in 145 subjects. The effects of Lbp downregulation, using lipid encapsulated unlocked nucleomonomer agent containing chemically modified-siRNA delivery system, were evaluated in mice. RESULTS: Plasma LBP levels were associated with fat mass and leptin levels in women with obesity, but not in men with obesity. In mice, plasma LBP downregulation led to reduced weight, fat mass and leptin gain after a high-fat and high-sucrose diet (HFHS) in females, in parallel to increased expression of adipogenic and thermogenic genes in visceral adipose tissue. This was not observed in males. Plasma LBP downregulation avoided the increase in serum LPS levels in HFHS-fed male and female mice. Serum LPS levels were positively correlated with body weight and fat mass gain, and negatively with markers of adipose tissue function only in female mice. The sexually dimorphic effects were replicated in mice with established obesity. Of note, LBP downregulation led to recovery of estrogen receptor alpha (Esr1) mRNA levels in females but not in males. CONCLUSION: LBP seems to exert a negative feedback on ERα-mediated estrogen action, impacting on genes involved in thermogenesis. The known decreased estrogen action and negative effects of metabolic endotoxemia may be targeted through LBP downregulation.

A microRNA Cluster Controls Fat Cell Differentiation and Adipose Tissue Expansion By Regulating SNCG.

The H19X-encoded miR-424(322)/503 cluster regulates multiple cellular functions. Here, it is reported for the first time that it is also a critical linchpin of fat mass expansion. Deletion of this miRNA cluster in mice results in obesity, while increasing the pool of early adipocyte progenitors and hypertrophied adipocytes. Complementary loss and gain of function experiments and RNA sequencing demonstrate that miR-424(322)/503 regulates a conserved genetic program involved in the differentiation and commitment of white adipocytes. Mechanistically, it is demonstrated that miR-424(322)/503 targets γ-Synuclein (SNCG), a factor that mediates this program rearrangement by controlling metabolic functions in fat cells, allowing adipocyte differentiation and adipose tissue enlargement. Accordingly, diminished miR-424(322) in mice and obese humans co-segregate with increased SNCG in fat and peripheral blood as mutually exclusive features of obesity, being normalized upon weight loss. The data unveil a previously unknown regulatory mechanism of fat mass expansion tightly controlled by the miR-424(322)/503 through SNCG.

Iron status influences non-alcoholic fatty liver disease in obesity through the gut microbiome.

BACKGROUND: The gut microbiome and iron status are known to play a role in the pathophysiology of non-alcoholic fatty liver disease (NAFLD), although their complex interaction remains unclear. RESULTS: Here, we applied an integrative systems medicine approach (faecal metagenomics, plasma and urine metabolomics, hepatic transcriptomics) in 2 well-characterised human cohorts of subjects with obesity (discovery n = 49 and validation n = 628) and an independent cohort formed by both individuals with and without obesity (n = 130), combined with in vitro and animal models. Serum ferritin levels, as a markers of liver iron stores, were positively associated with liver fat accumulation in parallel with lower gut microbial gene richness, composition and functionality. Specifically, ferritin had strong negative associations with the Pasteurellaceae, Leuconostocaceae and Micrococcaea families. It also had consistent negative associations with several Veillonella, Bifidobacterium and Lactobacillus species, but positive associations with Bacteroides and Prevotella spp. Notably, the ferritin-associated bacterial families had a strong correlation with iron-related liver genes. In addition, several bacterial functions related to iron metabolism (transport, chelation, heme and siderophore biosynthesis) and NAFLD (fatty acid and glutathione biosynthesis) were also associated with the host serum ferritin levels. This iron-related microbiome signature was linked to a transcriptomic and metabolomic signature associated to the degree of liver fat accumulation through hepatic glucose metabolism. In particular, we found a consistent association among serum ferritin, Pasteurellaceae and Micrococcacea families, bacterial functions involved in histidine transport, the host circulating histidine levels and the liver expression of GYS2 and SEC24B. Serum ferritin was also related to bacterial glycine transporters, the host glycine serum levels and the liver expression of glycine transporters. The transcriptomic findings were replicated in human primary hepatocytes, where iron supplementation also led to triglycerides accumulation and induced the expression of lipid and iron metabolism genes in synergy with palmitic acid. We further explored the direct impact of the microbiome on iron metabolism and liver fact accumulation through transplantation of faecal microbiota into recipient's mice. In line with the results in humans, transplantation from 'high ferritin donors' resulted in alterations in several genes related to iron metabolism and fatty acid accumulation in recipient's mice. CONCLUSIONS: Altogether, a significant interplay among the gut microbiome, iron status and liver fat accumulation is revealed, with potential significance for target therapies. Video abstract.

Activation of Endogenous H2S Biosynthesis or Supplementation with Exogenous H2S Enhances Adipose Tissue Adipogenesis and Preserves Adipocyte Physiology in Humans.

Aims: To investigate the impact of exogenous hydrogen sulfide (H2S) and its endogenous biosynthesis on human adipocytes and adipose tissue in the context of obesity and insulin resistance. Results: Experiments in human adipose tissue explants and in isolated preadipocytes demonstrated that exogenous H2S or the activation of endogenous H2S biosynthesis resulted in increased adipogenesis, insulin action, sirtuin deacetylase, and PPARγ transcriptional activity, whereas chemical inhibition and gene knockdown of each enzyme generating H2S (CTH, CBS, MPST) led to altered adipocyte differentiation, cellular senescence, and increased inflammation. In agreement with these experimental data, visceral and subcutaneous adipose tissue expression of H2S-synthesising enzymes was significantly reduced in morbidly obese subjects in association with attenuated adipogenesis and increased markers of adipose tissue inflammation and senescence. Interestingly, weight-loss interventions (including bariatric surgery or diet/exercise) improved the expression of H2S biosynthesis-related genes. In human preadipocytes, the expression of CTH, CBS, and MPST genes and H2S production were dramatically increased during adipocyte differentiation. More importantly, the adipocyte proteome exhibiting persulfidation was characterized, disclosing that different proteins involved in fatty acid and lipid metabolism, the citrate cycle, insulin signaling, several adipokines, and PPAR, experienced the most dramatic persulfidation (85-98%). Innovation: No previous studies investigated the impact of H2S on human adipose tissue. This study suggests that the potentiation of adipose tissue H2S biosynthesis is a possible therapeutic approach to improve adipose tissue dysfunction in patients with obesity and insulin resistance. Conclusion: Altogether, these data supported the relevance of H2S biosynthesis in the modulation of human adipocyte physiology. Antioxid. Redox Signal. 35, 319-340.

Clinical and economic impact of the taurolidine lock on home parenteral nutrition.

INTRODUCTION: catheter-related bloodstream infections (CRBSI) are one of the most serious concerns in patients on home parenteral nutrition (HPN) which involve high morbidity and cost for the healthcare system. In the last years, taurolidine lock has proven to be beneficial in the prevention of CRBSI; however, the evidence of its efficiency is limited. OBJECTIVE: to determine if taurolidine lock is a cost-effective intervention in patients on HPN. MATERIALS AND METHODS: retrospective study in patients on HPN with taurolidine lock. We compared the CRBSI rate and cost of its complications before and during taurolidine lock. RESULTS: thirteen patients, six (46%) males and seven (54%) females, with a mean age of 61.08 (SD = 14.18) years received taurolidine lock. The total days of catheterization pre and per-taurolidine were 12,186 and 5,293, respectively. The underlying disease was benign in five patients (38.5%) and malignant in eight (61.5%). The CRBSI rate pre vs per-taurolidine was 3.12 vs 0.76 episodes per 1,000 catheter days (p = 0.0058). When the indication was a high CRBSI rate, this was 9.72 vs 0.39 (p < 0.001) in pre and per-taurolidine period respectively. No differences have been observed in the occlusion rates. None of the patients reported any adverse effects. The total cost of CRBSI in the pre-taurolidine period was 151,264.14 euros vs 24,331.19 euros in the per-taurolidine period. CONCLUSIONS: our study shows that taurolidine lock is a cost-effective intervention in patients on HPN with high risk of CRBSI.

Role of fermented beverages in the maintenance of weight loss / Papel de las bebidas fermentadas en el mantenimiento del peso perdido.

Obesity is a very prevalent disease with multiple chronic complications that decrease or disappear after a small (5-10%) but maintained weight loss. Nevertheless, maintaining weight loss after the treatment is very difficult and it involves one of the biggest challenges to control this epidemic. Although the reasons that contribute to regain the lost weight are diverse and related to the biological response to caloric restriction and the lack of adherence to treatment, up to 20% of the patients are able to keep it off. The keys to success, involve the maintenance of healthy habits, exercise and a reasonable daily calorie intake to allow a normal way of life, without sacrificing the social life. At this point, learning to distinguish food and drink options in a society where social life often revolves around the table is very important. We review the keys to keep the weight off after a diet as well as the role of fermented beverages such as beer, in this process. In conclusion, maintenance the weight loss is harder than losing it. The mild-to-moderate consumption of fermented beverages such as beer is not associated with weight increase.

La obesidad es una enfermedad muy prevalente con múltiples complicaciones crónicas que se reducen o desaparecen tras pérdidas pequeñas (5-10%) pero mantenidas de peso. Sin embargo, mantener la pérdida de peso tras el tratamiento es muy difícil, siendo uno de los mayores retos en el control de esta enfermedad. Aunque las razones que contribuyen a recuperar el peso perdido son de diversa índole, relacionadas con la respuesta biológica a la restricción calórica y con la pérdida de adherencia al tratamiento, hasta un 20% de los pacientes son capaces de mantenerlo. Las claves del éxito están relacionadas con el mantenimiento de los hábitos de vida saludable, el ejercicio físico y una ingesta calórica razonable que permita realizar una vida normal, sin pérdida de vida social. En este sentido, aprender a distinguir las opciones de comida y bebida en una sociedad donde la vida social gira en torno a la mesa en muchas ocasiones es muy importante. Revisamos en este artículo las claves para mantener el peso tras una dieta, así como el papel de las bebidas fermentadas, en especial, la cerveza, en este proceso. En conclusión, mantener el peso perdido es más difícil que perderlo. El consumo leve-moderado de bebidas fermentadas como la cerveza no se asocia con incremento del peso.