Glucose and Fatty Acid Metabolism in a 3 Tissue In-Vitro Model Challenged with Normo- and Hyperglycaemia

Nutrient balance in the human body is maintained through systemic signaling between different cells and tissues. Breaking down this circuitry to its most basic elements and reconstructing the metabolic network in-vitro provides a systematic method to gain a better understanding of how cross-talk between the organs contributes to the whole body metabolic profile and of the specific role of each different cell type. To this end, a 3-way connected culture of hepatocytes, adipose tissue and endothelial cells representing a simplified model of energetic substrate metabolism in the visceral region was developed. The 3-way culture was shown to maintain glucose and fatty acid homeostasis in-vitro. Subsequently it was challenged with insulin and high glucose concentrations to simulate hyperglycaemia. The aim was to study the capacity of the 3-way culture to maintain or restore normal circulating glucose concentrations in response to insulin and to investigate the effects these conditions on other metabolites involved in glucose and lipid metabolism. The results show that the system’s metabolic profile changes dramatically in the presence of high concentrations of glucose, and that these changes are modulated by the presence of insulin. Furthermore, we observed an increase in E-selectin levels in hyperglycaemic conditions and increased IL-6 concentrations in insulin-free-hyperglycaemic conditions, indicating, respectively, endothelial injury and proinflammatory stress in the challenged 3-way system

Synergistic Interactions Among Metabolic Syndrome Components and Homeostasis Model Assessment of Insulin Resistance in a Middle-Aged General Population over Time.

Background: Insulin resistance is considered a hallmark feature of the metabolic syndrome, but how metabolic syndrome components and insulin resistance measures interact over time is unclear. The homeostasis model assessment of insulin resistance (HOMA-IR) is a static index of insulin resistance typically used in epidemiological studies. We explored how HOMA-IR is affected by clustering metabolic syndrome components over time in a population of middle-aged, healthy subjects. Methods: A total of 1757 subjects aged 41.3 +/- 7.5 years (39% males) free from diabetes at baseline were followed-up for a median of 5.7 years. At baseline and at the end of observation, we determined metabolic syndrome components and HOMA-IR. Results: Cross-sectionally, HOMA-IR was synergistically increased by clustering of at least two to three metabolic syndrome components as determined at baseline and at study end by departure from additivity. Some combinations of metabolic syndrome components were associated with a significant synergic increase in HOMA-IR, and some combinations of two components entailed a synergistic risk of developing metabolic syndrome. Over time, the average change in HOMA-IR was more than additively affected by change in the number of metabolic syndrome components. Baseline HOMA-IR values were predictive of incident metabolic syndrome independent from age, sex, and each metabolic syndrome component. Conclusions: We show synergistic interaction between clustering metabolic syndrome components and insulin resistance, estimated by HOMA-IR, cross-sectionally and over time. This more than additive effect explains the incremental value of HOMA-IR in predicting metabolic risk

Geosite Assessment in the Beigua UNESCO Global Geopark (Liguria, Italy): A Case Study in Linking Geoheritage with Education, Tourism, and Community Involvement

The inventory and the assessment of geosites plays a very important role in highlighting scientific, geotouristic, and geoeducational potential, as well as the ability to identify any criticalities and vulnerabilities of the geological heritage of a territory. Within a geopark, these assessment activities are also crucial for developing land management strategies and policies that not only meet the need to protect geological and natural heritage, but also to promote sustainable economic development of the area and local communities. The Beigua UNESCO Global Geopark (Liguria, Italy) includes fifty-four sites known for their significant geological values. In this work, we have combined a study aimed at the qualitative and quantitative evaluation of 10 of the 54 sites with the results of an analysis of the educational, touristic, and land management activities that have been developed on these sites from 2011 to 2021. The quantitative assessment of the ten selected sites reveals their high scientific value and considerable touristic and/or educational potential. Thus, they represent not only scientific geological heritage to be preserved but also a significant tourism resource for the geopark territory. This is confirmed by the great success of geotouristic and geoeducational initiatives developed in the park over the last ten years, and by the growing involvement of the local communities, institutions, entrepreneurial activities, as well as environmental, sports, and cultural associations. These results highlight some important aspects for the management of geological heritage and associated values within a geopark

Insulin-induced glucose control improves HDL cholesterol levels but not reverse cholesterol transport in type 2 diabetic patients.

Type 2 diabetes (T2D) is characterized by low HDL cholesterol (HDL-C) and HDL dysfunction. We herein tested whether lowering HbA1c affects HDL-C and reverse cholesterol transport (RCT). Forty-two uncontrolled T2D patients initiating basal insulin were included. HbA1c, HDL-C and RCT were assessed at baseline and after 6 months. At baseline, HDL-C and RCT were directly correlated (r = 0.50; p < 0.001). After 6 months of insulin therapy, HbA1c dropped from 8.8 +/- 0.16% to 7.1 +/- 0.1%, while average HDL-C and RCT did not change. Follow-up HDL-C and RCT were still correlated (r = 0.31; p = 0.033) and Delta HDL-C correlated with Delta RCT (r = 0.32; p = 0.029). Delta HbA1c correlated with Delta HDL-C (r = 0.43, p = 0.001), but not with Delta RCT. In patients with Delta HbA1c above the median value (1.3%), HDL-C (but not RCT) increased significantly. In conclusion, glucose control correlates with increased HDL-C, but not with improved RCT. Thus, persistent HDL dysfunction despite improved HbA1c and HDL-C can contribute to residual cardiovascular risk in T2

Acute effects of linagliptin on progenitor cells, monocyte phenotypes, and soluble mediators in type 2 diabetes

Context: Circulating cells, including endothelial progenitor cells (EPCs) and monocyte subtypes, are involved in diabetic complications. Modulation of these cells may mediate additional benefits of glucose-lowering medications. Objective: We assessed whether the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin acutely modifies EPCs and monocyte subsets in patients with type 2 diabetes. Design: This was a randomized, crossover, placebo-controlled trial. Setting: The study was conducted at a tertiary referral diabetes outpatient clinic. Patients: Forty-six type 2 diabetes patients with (n = 18) or without (n = 28) chronic kidney disease (CKD) participated in the study. Intervention: Intervention included a 4-day treatment with linagliptin 5mg or placebo during two arms separated by a 2-week washout. Main Outcome Measures: Before and after each treatment, we determined the levels of circulating progenitor cells (CD34, CD133, KDR) and monocyte subtypes (CD14/CD16, chemokine and scavenger receptors) and the concentrations of soluble mediators. Results: Compared with placebo, linagliptin increased CD34(+) CD133(+) progenitor cells (placebo subtracted effect 40.4 +/- 18.7/10(6); P = .036), CD34(+) KDR+ EPCs (placebo subtracted effect 22.1 +/- 10.2/10(6); P = .036), and CX(3)CR1(bright) monocytes (placebo subtracted effect 1.7 +/- 0.8%; P = .032). Linagliptin abated DPP-4 activity by greater than 50%, significantly increased active glucagon-like peptide-1 and stromal cell-derived factor-1 alpha, and reduced monocytechemotactic protein-1, CCL22, and IL-12. Patients with CKD, as compared with those without, had lower baseline CD133(+) and CD34(+) CD133(+) cells and had borderline reduced CD34(+) and CD34(+) KDR+ cells. The effects of linagliptin on progenitor cells and monocyte subtypes were similar in patients with or without CKD. Fasting plasma glucose, triglycerides and free fatty acids were unaffected. Conclusions: DPP-4 inhibition with linagliptin acutely increases putative vasculoregenerative and antiinflammatory cells. Direct effects of DPP-4 inhibition may be important to lower vascular risk in diabetes, especially in the presence of CKD

Development of the metabolic syndrome and electrocardiographic features of left ventricular hypertrophy in middle-aged working subjects.

Background and aims. The metabolic syndrome (MS) leads to excess cardiovascular disease, including heart failure. Left ventricular hypertrophy (LVH) is common in MS patients, but it is unknown whether onsets of the MS and LVH coincide. Herein, we tested the association between development of the MS and of electrocardiographic LVH in a cohort of middle-aged individuals. Methods. We included 303 working subjects (mean age 43.0\ub16.2; 41% males), followed-up for 4.3\ub10.8 years. ATP-III MS components were determined. Electrocardiographic LVH features were assessed by the Sokolow and Cornell voltage indexes and the Rohmilt-Estes score. Results. At baseline, the Cornell index was significantly higher in subjects with (n=55; 18.2%) than in those without MS (12.8\ub16.4 vs 10.9\ub15.4 mm; p=0.023), while the Sokolow index and Rohmilt- Estes score were not different. At follow-up, individuals who developed (n=51) compared to those who did not develop MS showed a significant increase in Cornell voltage index (1.0\ub10.6 vs - 0.55\ub10.3 mm; p=0.035) and in Rohmilt-Estes score (0.17\ub10.17 vs -0.08\ub10.04; p=0.028). The change in Cornell index over time was directly correlated with change in the number of MS components (r=0.133; p=0.02) and HOMA-IR (r=0.117; p=0.046). The association between MS onset and increase in Cornell index / Rohmilt-Estes score was independent from confounders. Conclusions. In a young population of working subjects, the development of MS is associated with worsening features of LVH. Early LVH electrocardiographic screening in young subjects who develop the MS should be considered and performed using the Cornell voltage inde

A Visfatin Promoter Polymorphism Is Associated with Low-Grade Inflammation and Type 2 Diabetes*

Visfatin (also known as pre-B cell colony-enhancing factor, or PBEF) is a pro-inflammatory adipokine expressed predominantly in visceral fat. We investigated whether polymorphisms at the visfatin/PBEF locus influence the risk of type 2 diabetes (T2D). Linkage disequilibrium analysis of 52 single nucleotide polymorphisms spanning the entire gene (34.7 kb) plus 20.5 kb of the upstream region and 25.5 kb of the downstream region revealed a single haplotype block that could be tagged by seven single nucleotide polymorphisms. These seven tags were typed in a group of T2D patients (n = 814) and a group of non-diabetic controls (n = 320) of white origin. A significant association was observed at -948C>A, with minor allele frequencies of 0.157 in T2D cases and 0.119 in non-diabetic controls (p = 0.021). In a non-diabetic population (n = 630), the same -948 allele that conferred increased risk of T2D was significantly associated with higher plasma levels of fibrinogen and C-reactive protein (p = 0.0022 and 0.0038, respectively). However, no significant associations were observed with BMI, waist circumference, serum glucose levels, or fasting insulin levels. Our findings suggest that the visfatin/PBEF gene may play a role in determining T2D susceptibility, possibly by modulating chronic, low-grade inflammatory responses

Schematic of the 3-way connected culture.

<p>QV is the low shear Quasi-Vivo chamber for hepatocytes and adipose tissue and LFC is the high shear laminar flow chamber for endothelial cells. The flow rate used was 250 µL/min. Total circuit volume is 15 mL, with 3 mL of priming volume per chamber and associated tubing and 6 mL in the mixing chamber and pump.</p

Glucose, FFA and glycerol in the 3-way cultures in FS, PARS, D1 and D2 conditions.

<p>A) Glucose variations over time. B) Changes in medium glucose concentration with respect to initial media concentration at 48 H (* = p<0.05 vs. D1). C) FFA variations over time. D) Changes in medium FFA concentration with respect to initial media concentration at 48 H (* = p<0.05 vs. FS; ** = p<0.05 vs. D1). E) Glycerol variations over time. F) Changes in medium glycerol concentration with respect to initial media concentration at 48 H (* = p<0.05 vs. D1). In all cases time 0 represents the levels of metabolites in fresh media. Data are expressed as means ± SD (3≤n≤6). Error bars represent the standard deviation.</p