The DAPA-DIET study: Metabolic response to Dapagliflozin combined with dietary carbohydrate restriction in patients with Type 2 Diabetes Mellitus and Obesity-A longitudinal cohort study.

OBJECTIVE: The cardio-renal benefits of sodium glucose-like transporter 2 inhibitor (SGLT2i) therapies have been demonstrated in patients with and without type 2 diabetes. However, no studies have explored the long-term metabolic effects of SGLT2i, combined with dietary carbohydrate restriction. Our primary objective was to describe long-term changes in weight, energy expenditure, appetite and body composition after 12 months of Dapagliflozin therapy, with carbohydrate restriction, in people with type 2 diabetes and obesity. Our secondary objective was to assess changes in adiponectin and leptin. METHOD: This was a 12-month cohort study in a secondary care setting. Participants (n = 18) with type 2 diabetes (T2D) and class 3 obesity underwent baseline indirect calorimetry for determination of 24-h energy expenditure, body composition, fasting serum leptin and adiponectin levels, and appetitive assessments. Following initiation of Dapagliflozin (and dietary carbohydrate restriction), measurements were repeated at monthly intervals up to 12 months. RESULTS: Mean starting weight of participants was 129.4 kg (SD 25.9), mean BMI 46.1 kg/m2 (SD 8.3) and mean HbA1c 53.9 mmol/mol (14.1). Seventeen participants completed the study; after 12 months of Dapagliflozin and dietary carbohydrate restriction, mean weight loss was 8.1 kg (SD 11.3 kg; p = .009). This was mediated by reduced fat mass (mean loss, 9.9 kg; SD 10.4 kg; p = .002) associated with reduced serum leptin at 12 months (mean reduction 11,254 pg/ml; SD 16,075; p = .011). There were no significant changes in self-reported appetite, 24-h energy expenditure or serum adiponectin during follow-up. CONCLUSION: In this study, combined Dapagliflozin therapy and carbohydrate restriction in patients with T2D and obesity resulted in a significant reduction of body weight and fat mass at 12 months without any discernible changes in energy expenditure or appetite. These results offer a scientific and clinical rationale to conduct an exploratory trial investigating the effects of a low carbohydrate diet combined with SGLT2 inhibitors in patients with T2D.

Novel perspectives of sodium handling in type 2 diabetes mellitus.

INTRODUCTION: As a key regulator of body water, sodium homeostasis forms an essential component of human physiology. Type 2 Diabetes Mellitus (T2D)-associated sodium overload stems from chronic renal retention of sodium, contributing toward the development of adverse cardiovascular sequelae. AREAS COVERED: Our traditional model of sodium regulation invokes two compartments: extracellular fluid (ECF [plasma and interstitial fluid]) and intracellular fluid (ICF). Data from the Mars program reveal inconsistencies with this two-space model, including mismatches between net body sodium and water. Recent data utilizing 23Na magnetic resonance imaging (MRI) show a preponderance of bound sodium within human dermis, consistent with a third space repository and providing compelling evidence to support a three-space model in which dermal sodium binding facilitates sodium homeostasis within the ECF and ICF. This buffer is impaired in T2D, with diminishment of dermal bound sodium that may promote deleterious sequelae of sodium overload within the ECF and ICF. EXPERT OPINION: Future studies should focus on novel therapeutic opportunities for sodium regulation in T2D and other conditions of sodium dysregulation. The ratio of free:bound dermal sodium (reflecting sodium storage capacity) could be utilized as a clinical biomarker for salt and water balance, to improve diagnostic accuracy and facilitate clinical decision-making.

Body composition in heart failure and the impact of cardiac resynchronisation therapy: a proof-of-concept study.

Aims: Body composition (BC) is known to alter in heart failure. Cardiac resynchronisation therapy (CRT) improves left ventricular geometry but the impact on BC is unknown. Our aim was to evaluate BC in these patients before and after CRT implantation. Methods: Prospective proof-of-concept pilot study of heart failure patients undergoing CRT between September 2014 and December 2015. Assessments performed pre-CRT and post-CRT (6 weeks and 6 months) were: BC parameters (using air-displacement plethysmography), New York Heart Failure classification for assessing symptom severity, echocardiography to assess left ventricular geometry, electrocardiography, Minnesota Heart Failure Questionnaire and N-terminal probrain natriuretic peptide (NT-pro-BNP). Repeated measures analysis of variance was performed to assess relative change over time and potential correlations. Results: Twenty-five patients were recruited; mean-age (±SD) was 73.4±10.0 years, 23 males, 18 CRT defibrillators (remainder CRT pacemakers), 16 had ischaemic aetiology, 6 diabetics, 17 with left bundle-branch morphology on ECG and 10 had atrial fibrillation. Significant inverse correlations were observed in the first 6 weeks following CRT between fat mass and left ventricular end-diastolic volume (r=-0.69, p<0.01) and NT-pro-BNP and fat mass (r=0.41, p=0.05). No significant differences were noted over 6 months. There was an observed trend towards reduced fat mass in the first 6 weeks post-CRT implant driven by non-responders. There was no significant difference between responders and non-responders in BC over 6 months. Conclusion: This is the first study to observe interplay between BC and cardiac geometry/function following CRT; a trend in overall fat mass reduction was noted following CRT and merits further study.

Characterisation of circulating biomarkers before and after cardiac resynchronisation therapy and their role in predicting CRT response: the COVERT-HF study.

Aims: Cardiac resynchronisation therapy (CRT) is effective treatment for selected patients with heart failure (HF) but has ~30% non-response rate. We evaluated whether specific biomarkers can predict outcome. Methods: A prospective single-centre pilot study of consecutive unselected patients undergoing CRT for HF between November 2013 and December 2015 evaluating cardiac extracellular matrix biomarkers and micro-ribonucleic acid (miRNA) expression before and after CRT assessing ability to predict functional response and survival. Each underwent three assessments (pre-implant, 6 weeks and 6 months postimplant) including: New York Heart Association (NYHA) class, echocardiography, electrocardiography, 6 min walk test (6MWT), Minnesota Living with Heart Failure Questionnaire (MLHFQ) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP). Plasma markers of cardiac fibrosis assessed were: N-terminal pro-peptides of collagen I and III, collagen I C-terminal telopeptides (CTx) and matrix metalloproteinases (MMP-2 and MMP-9) as well as a panel of miRNAs (miRNA-21, miRNA-30d, miRNA-122, miRNA-133a, miRNA-210 and miRNA-486). Results: A total of 52 patients were recruited; mean age (±SD) was 72.4±9.4 years; male=43 (82.7%), ischaemic aetiology=30 (57.7%), mean QRS duration=166.4±23.5 ms, left bundle branch block (LBBB) morphology = 39 (75.0%), mean NYHA=2.7±0.6, 6MWT=238.8±130.6 m, MLHFQ=46.4±21.3 and left ventricular ejection fraction (LVEF)=24.3%±8.0%. Mean follow-up=1.7±0.3 and 5.8±0.7 months. There were 27 (55.1%) functional responders (3 no definable 6-month response; 2 missed assessments and 1 long-term lead displacement). No marker predicted response, however, CTx and LBBB trended most towards predicting functional response. Conclusion: No specific biomarkers reached significance for predicting functional response to CRT. CTx showed a trend towards predicting response and warrants further study. Trial registration number: NCT02541773.

Extracellular cardiac matrix biomarkers in patients with reduced ejection fraction heart failure as predictors of response to cardiac resynchronisation therapy: a systematic review.

OBJECTIVE: Cardiac resynchronisation therapy (CRT) is an effective therapy for selected patients with heart failure (HF); however, a significant non-response rate exists. We examined current evidence on extracellular cardiac matrix (ECM) biomarkers in predicting response following CRT. METHODS: Complete literature review of PubMed, Ovid SP MEDLINE, Cochrane Library and TRIP, reference lists, international cardiology conferences and ongoing studies between December 1999 and December 2015 conducted according to prospectively registered study selection and analysis criteria (PROSPERO:CRD42016025864) was performed. All observational and randomised control trials (RCT) were included if they tested prespecified ECM biomarkers' ability to predict CRT response. Risk of bias assessment and data extraction determined pooling of included studies was not feasible due to heterogeneity of the selected studies. RESULTS: A total of 217 studies were screened; six (five prospective cohort and one RCT substudy) were included in analysis with 415 participants in total. Study sizes varied (n=55-260), cohort characteristics contrasted (male: 67.8%-83.6%, ischaemic aetiology: 40.2%-70.3%) and CRT response definitions differed (three clinical/functional, three echocardiographic). Consistent observation in all ECM biomarker behaviour before and after CRT implantation was not observed between studies. Lower type I and type III collagen synthesis biomarkers (N-terminal propeptides of type I and III procollagens) expression demonstrated replicated ability to predict reverse left ventricular remodelling. CONCLUSION: Collagen synthesis biomarkers offer the most potential as ECM biomarkers for predicting CRT response. Heterogeneity between these studies was large and limited the ability to pool and compare results numerically. Use of different response definitions was one of the biggest challenges.

The interplay between heart failure, metabolism and body composition.

A complex interplay exists between heart failure, metabolic status and body composition. The idiosyncrasies of these relationships are poorly understood, but they offer prognostic value and potential clinical utility. Current understanding of this relationship and known clinical value are discussed in this article.

Elevated concentrations of retinol-binding protein-4 (RBP-4) in gestational diabetes mellitus: negative correlation with soluble vascular cell adhesion molecule-1 (sVCAM-1).

BACKGROUND: Retinol-binding protein-4 (RBP-4) may increase insulin resistance (IR) in animals, with elevated levels reported in humans with obesity and type 2 diabetes. There are, however, few data on concentrations of RBP-4 in gestational diabetes mellitus (GDM). METHODS: We measured fasting serum levels of RBP-4, soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) in 50 women at 28 weeks of gestation, divided according to the results of a 50 g glucose challenge test (GCT) and a 75 g oral glucose tolerance test (OGTT): (1) controls (n = 20), normal responses to both GCT and OGTT; (2) intermediate group (IG) (n = 15): false positive GCT, but normal OGTT; and (3) GDM group (n = 15), both GCT and OGTT abnormal. IR was assessed by homeostasis model assessment (HOMA-IR) and by insulin resistance index (IRI) based on glycemia and insulinemia during OGTT. RESULTS: All groups were matched for age and body mass index (BMI). RBP-4 levels (microg/ml, mean+/-standard deviation) were higher in women with GDM vs. controls (53.9 +/- 17.9 vs. 29.7 +/- 13.9, p < or = 0.001), with a trend towards higher RBP-4 in GDM compared with IG (38.0 +/- 19.3, p = 0.07). There was no significant correlation between RBP-4 and age, BMI, insulin, IRI or HOMA-IR, but there was a moderate, significant negative correlation between RBP-4 and sVCAM-1 (r(2) = 0.20, p = 0.001). CONCLUSIONS: RBP-4 levels are elevated in women with GDM, but do not correlate with IR indices and correlate negatively with sVCAM-1. The physiological significance of RBP-4 rise in women with GDM remains to be elucidated.

Omentin-1, a novel adipokine, is decreased in overweight insulin-resistant women with polycystic ovary syndrome: ex vivo and in vivo regulation of omentin-1 by insulin and glucose.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is associated with insulin resistance and obesity. Recent studies have shown that plasma omentin-1 levels decrease with obesity. Currently, no data exist on the relative expression and regulation of omentin-1 in adipose tissue of women with PCOS. The objective of this study was to assess mRNA and protein levels of omentin-1, including circulating omentin-1, in omental adipose tissue of women with PCOS and matched control subjects. Ex vivo and in vivo regulation of adipose tissue omentin-1 was also studied. RESEARCH DESIGN AND METHODS: Real-time RT-PCR and Western blotting were used to assess mRNA and protein expression of omentin-1. Plasma omentin-1 was measured by enzyme-linked immunosorbent assay. The effects of d-glucose, insulin, and gonadal and adrenal steroids on adipose tissue omentin-1 were analyzed ex vivo. The in vivo effects of insulin (hyperinsulinemia) on omentin-1 levels were also assessed by a prolonged insulin-glucose infusion. RESULTS: In addition to decreased plasma omentin-1 levels in women with PCOS (P < 0.05), compared with control subjects, there was significantly lower levels of omentin-1 mRNA (P < 0.01) and protein (P < 0.05) in omental adipose tissue of women with PCOS (P < 0.01). Furthermore, in omental adipose tissue explants, insulin and glucose significantly dose-dependently decreased omentin-1 mRNA expression, protein levels, and secretion into conditioned media (P < 0.05, P < 0.01). Also, hyperinsulinemic induction in healthy subjects significantly reduced plasma omentin-1 levels (P < 0.01). CONCLUSIONS: Our novel findings reveal that omentin-1 is downregulated by insulin and glucose. These may, in part, explain the decreased omentin-1 levels observed in our overweight women with PCOS.

Raised plasma adiponectin levels in type 1 diabetic pregnancies.

OBJECTIVES: Adiponectin has antidiabetic properties. Our aim was to determine plasma adiponectin levels during pregnancy and postpartum (PP), in women with type 1 diabetic mellitus (T1DM) and nondiabetic (ND) women. PATIENTS AND METHODS: Fasting plasma adiponectin and leptin levels were measured in 20 ND and 19 T1DM women, at 20 and 30 weeks' gestation, and 9 months' PP. Insulin measurements were made in ND women. RESULTS: In both groups, after accounting for body mass index (BMI), leptin levels increased during pregnancy (P < 0.01) and were significantly higher than PP (P < 0.001). However, no significant differences in leptin levels were noted between both groups at any stage (P = 0.46). Conversely, adiponectin levels were higher in T1DM at all stages of the study (P < 0.001). A significant fall in adiponectin levels was seen between 20 and 30 weeks' gestation in both groups (ND: P < 0.001; T1DM: P < 0.05); however, this decrease was attenuated in the T1DM group. Adiponectin levels PP were significantly higher than at 30 weeks (ND: P < 0.001; T1DM: P < 0.001). Furthermore, in T1DM, adiponectin appeared to correlate negatively with leptin, but only reached significance PP (r = -0.46, P < 0.001). In the ND group, adiponectin correlated negatively with both leptin (PP: r = -0.56, P < 0.0001) and insulin (P < 0.005). CONCLUSIONS: Higher adiponectin levels were noted in T1DM throughout gestation compared to ND pregnancies, with no difference in leptin levels. The significance of these findings needs to be determined.

Circadian rhythmicity of salivary leptin in healthy subjects.

In humans, circulating leptin correlates with body weight and fat mass. The main source of leptin is adipose tissue although placenta has been shown to produce leptin. More recently leptin and its receptor have been found in gastric mucosa and salivary gland. In the present study, we set to confirm the presence of leptin in human saliva and salivary gland, and if present, investigate whether salivary leptin exhibited circadian rhythmicity. Saliva and plasma were collected at 2 h intervals for 24 h in 12 healthy volunteers (6 females; 6 males). As previously described in human saliva and salivary gland, we have confirmed the presence of leptin at both mRNA and protein level. Leptin concentrations were significantly higher in plasma than saliva (p = 0.002), and a strong correlation between salivary and plasma leptin was demonstrated (r = 0.76; p < 0.001). Salivary leptin, like plasma leptin, showed circadian variations in both men and women, with a peak around 2400 h and a nadir at 1000 h. Both, mean 24-h salivary leptin and plasma leptin concentrations were significantly higher in women than men (p < 0.05; p < 0.01, respectively), but the ratios of salivary and plasma leptin concentrations were higher in men (p < 0.05), independent of other variables measured. In this study we have confirmed that leptin is synthesised and secreted by the human salivary gland, and have demonstrated for the first time that salivary leptin shows circadian variation. The precise role of salivary leptin needs to be elucidated. Our findings suggest that there may be differential regulation of leptin (salivary) between men and women. Finally, measurement of leptin in saliva is a simple, non-invasive and may be an acceptable alternative to plasma sampling.

Differential effects of GH replacement on the components of the leptin system in GH-deficient individuals.

GH therapy is associated with a reduction in fat mass and an increase in lean mass in subjects with GH deficiency (GHD). Leptin, like GH, plays an important role in the regulation of body composition. GH treatment has been shown to reduce serum leptin; however, the physiological interactions between the leptin system (free leptin, bound leptin, and soluble leptin receptor) and the GH/IGF-I system largely remain unknown. Twenty-five patients with childhood (n = 10) and adult-onset (n = 15) GHD were studied. GH status had previously been determined using an insulin tolerance test and/or an arginine stimulation test. The following parameters were recorded at baseline (V1) and then after 3 months (V2) and 6 months (V3) on GH treatment: fat mass, body mass index (BMI), and waist/hip ratio (WHR); blood samples were taken after an overnight fast for free leptin, bound leptin, soluble leptin receptor, insulin, and IGF-I. At V2 and V3, respectively, a fall in free leptin (P < 0.001 for each), and at V3 a fall in in percent fat mass (P < 0.001) were observed. There were no significant changes in BMI or WHR. Simultaneously, there was a rise in insulin (P = 0.068 and P < 0.001), IGF-I (P < 0.001 and P < 0.001), bound leptin (P = 0.005 and P < 0.001), and soluble leptin receptor (P = 0.61 and P < 0.001). A positive relationship was noted between free leptin and BMI (P < 0.001) and between free leptin and fat mass (P < 0.001), and a negative relationship was found between free leptin and IGF-I (P < 0.001) and, within patient, between free leptin and insulin (P < 0.001). There was no significant correlation between free leptin and WHR. Bound leptin had a positive association with IGF-I (P < 0.001) and insulin (P = 0.002) and a negative relationship with percent fat mass (P = 0.023). Soluble leptin receptor was also positively related to IGF-I (P < 0.001). In conclusion, our data suggest that the reduction in serum leptin with GH treatment, as noted by others, is mediated through a fall in free leptin. The fall in free leptin and in part the rise in bound leptin are most likely through a reduction in percent fat mass. However, the observed changes in free leptin and bound leptin and, more importantly, the rise in soluble leptin receptor, are not explained entirely by modifications in body composition and may be a direct result of GH/IGF-I.