Improvement of glycaemia and endothelial function by a new low-dose curcuminoid in an animal model of type 2 diabetes

Curcumin has been suggested as a promising treatment for metabolic diseases, but the high doses required limit its therapeutic use. In this study, a new curcuminoid is synthesised to increase curcumin anti-inflammatory and antioxidant potential and to achieve hypoglycaemic and protective vascular effects in type 2 diabetic rats in a lower dose. In vitro, the anti-inflammatory effect was determined through the Griess reaction, and the antioxidant activity through ABTS and TBARS assays. In vivo, Goto-Kakizaki rats were treated for 2 weeks with the equimolar dose of curcumin (40 mg/kg/day) or curcuminoid (52.4 mg/kg/day). Fasting glycaemia, insulin tolerance, plasma insulin, insulin signalling, serum FFA, endothelial function and several markers of oxidative stress were evaluated. Both compounds presented a significant anti-inflammatory effect. Moreover, the curcuminoid had a marked hypoglycaemic effect, accompanied by higher GLUT4 levels in adipose tissue. Both compounds increased NO-dependent vasorelaxation, but only the curcuminoid exacerbated the response to ascorbic acid, consistent with a higher decrease in vascular oxidative and nitrosative stress. SOD1 and GLO1 levels were increased in EAT and heart, respectively. Altogether, these data suggest that the curcuminoid developed here has more pronounced effects than curcumin in low doses, improving the oxidative stress, endothelial function and glycaemic profile in type 2 diabetes.info:eu-repo/semantics/publishedVersio

Mice with Type 2 Diabetes Present Significant Alterations in Their Tissue Biomechanical Properties and Histological Features

Type 2 diabetes mellitus (T2DM) is a complex metabolic disease often associated with severe complications that may result in patient morbidity or death. One T2DM etiological agent is chronic hyperglycemia, a condition that induces damaging biological processes, including impactful extracellular matrix (ECM) modifications, such as matrix components accumulation. The latter alters ECM stiffness, triggering fibrosis, inflammation, and pathological angiogenesis. Hence, studying ECM biochemistry and biomechanics in the context of T2DM, or obesity, is highly relevant. With this in mind, we examined both native and decellularized tissues of obese B6.Cg-Lepob/J (ob/ob) and diabetic BKS.Cg-Dock7m+/+LeprdbJ (db/db) mice models, and extensively investigated their histological and biomechanical properties. The tissues analyzed herein were those strongly affected by diabetes-skin, kidney, adipose tissue, liver, and heart. The referred organs and tissues were collected from 8-week-old animals and submitted to classical histological staining, immunofluorescence, scanning electron microscopy, rheology, and atomic force microscopy. Altogether, this systematic characterization has identified significant differences in the architecture of both ob/ob and db/db tissues, namely db/db skin presents loose epidermis and altered dermis structure, the kidneys have clear glomerulopathy traits, and the liver exhibits severe steatosis. The distribution of ECM proteins also pinpoints important differences, such as laminin accumulation in db/db kidneys and decreased hyaluronic acid in hepatocyte cytoplasm in both obese and diabetic mice. In addition, we gathered a significant set of data showing that ECM features are maintained after decellularization, making these matrices excellent biomimetic scaffolds for 3D in vitro approaches. Importantly, mechanical studies revealed striking differences between tissue ECM stiffness of control (C57BL/6J), obese, and diabetic mice. Notably, we have unveiled that the intraperitoneal adipose tissue of diabetic animals is significantly stiffer (G* ≈ 10,000 Pa) than that of ob/ob or C57BL/6J mice (G* ≈ 3000-5000 Pa). Importantly, this study demonstrates that diabetes and obesity selectively potentiate severe histological and biomechanical alterations in different matrices that may impact vital processes, such as angiogenesis, wound healing, and inflammation

Intestinal Epithelial Stem Cells: Distinct Behavior After Surgical Injury and Teduglutide Administration

Background: Previous studies suggest that intestinal epithelial stem cells (IESC), critical drivers of homeostasis and regeneration, include two subpopulations: crypt-based columnar and “position +4” stem cells, identified by Lgr5 and Bmi1 biomarkers, respectively. Teduglutide is an enterotrophic counterpart of glucagon-like peptide 2. This study aimed to investigate the response of putative IESC to surgical injury and teduglutide administration on an animal model of intestinal resection and anastomosis. Methods: Wistar rats (n = 59) were distributed into four groups: “Ileal Resection” versus “Laparotomy”, subsequently subdivided into “Postoperative Teduglutide Administration” versus “No Treatment”; and sacrificed at third or seventh days, with ileal sample harvesting. Flow cytometry was used to analyze epithelial stem cells with monoclonal antibodies against Lgr5, Bmi1 and also CD44, CD24, CD166, and Grp78 surface markers. Results: Surgical trauma induced an increase of epithelial stem cells population at third day (9.0 ± 0.3 versus 5.7 ± 0.3%, p = 0.0001), which was more intense and involved all subpopulations after ileal resection. At seventh day, teduglutide was significantly associated with higher proportion of Lgr5+/Bmi1− cells (5.8 ± 0.1 versus 2.9 ± 0.3%, p = 0.005) and, on the contrary, lower percentage of Lgr5−/Bmi1+ cells (0.03 ± 0.01 versus 1.9 ± 0.1%, p = 0.049) after ileal resection; and higher proportion of Lgr5+/Bmi1+ cells (1.7 ± 0.1 versus 1.1 ± 0.2%, p = 0.028) after isolated laparotomy. After surgery, Lgr5+/Bmi1− and Lgr5−/Bmi1+ subpopulations demonstrated an inverse correlation and both correlated negatively with Grp78 labeling index. Lgr5−/Bmi1+ and CD44+/CD24low/CD166+/Grp78+ cells proportions exhibited a high grade positive correlation. Conclusion: Those observations support the existence of two epithelial stem cells subpopulations with distinct behavior after surgical injury and teduglutide treatment

Chronic Intermittent Hypoxia Induces Early-Stage Metabolic Dysfunction Independently of Adipose Tissue Deregulation

Several studies demonstrated a link between obstructive sleep apnea (OSA) and the development of insulin resistance. However, the main event triggering insulin resistance in OSA remains to be clarified. Herein, we investigated the effect of mild and severe chronic intermittent hypoxia (CIH) on whole-body metabolic deregulation and visceral adipose tissue dysfunction. Moreover, we studied the contribution of obesity to CIH-induced dysmetabolic states. Experiments were performed in male Wistar rats submitted to a control and high-fat (HF) diet. Two CIH protocols were tested: A mild CIH paradigm (5/6 hypoxic (5% O2) cycles/h, 10.5 h/day) during 35 days and a severe CIH paradigm (30 hypoxic (5% O2) cycles, 8 h/day) during 15 days. Fasting glycemia, insulinemia, insulin sensitivity, weight, and fat mass were assessed. Adipose tissue hypoxia, inflammation, angiogenesis, oxidative stress, and metabolism were investigated. Mild and severe CIH increased insulin levels and induced whole-body insulin resistance in control animals, effects not associated with weight gain. In control animals, CIH did not modify adipocytes perimeter as well as adipose tissue hypoxia, angiogenesis, inflammation or oxidative stress. In HF animals, severe CIH attenuated the increase in adipocytes perimeter, adipose tissue hypoxia, angiogenesis, and dysmetabolism. In conclusion, adipose tissue dysfunction is not the main trigger for initial dysmetabolism in CIH. CIH in an early stage might have a protective role against the deleterious effects of HF diet on adipose tissue metabolism

Perfil tisular de factores de crecimiento postadministración de teduglutida en un modelo animal de anastomosis intestinal

Background: Teduglutide is an enterotrophic analogue of glucagon-like peptide-2, with an indirect and poorly understood mechanism of action, approved for the rehabilitation of short-bowel syndrome. This study aims to analyze the response of tissue growth factors to surgical injury and teduglutide administration on an animal model of intestinal anastomosis. Methods: Wistar rats (n = 59) were distributed into four groups: “ileal resection” or “laparotomy”, each one subdivided into “postoperative teduglutide administration” or “no treatment”; and sacrificed at the third or the seventh day, with ileal sample harvesting. Gene expression of insulin-like growth factor 1 (Igf1), vascular endothelial growth factor a (Vegfa), transforming growth factor β1 (Tgfβ1), connective tissue growth factor (Ctgf), fibroblast growth factor 2 (Fgf2), fibroblast growth factor 7 (Fgf7), epidermal growth factor (Egf), heparin-binding epidermal-like growth factor (Hbegf), platelet-derived growth factor b (Pdgfb) and glucagon-like peptide 2 receptor (Glp2r) was studied by real-time polymerase chain reaction. Results: Upregulation of Fgf7, Fgf2, Egf, Vegfa and Glp2r at the third day and of Pdgf at the seventh day was verified in the perianastomotic segment. Teduglutide administration was associated with higher fold-change of relative gene expression of Vegfa (3.6 ± 1.3 vs. 1.9 ± 2.0, p = 0.0001), Hbegf (2.2 ± 2.3 vs. 1.1 ± 0.9, p = 0.001), Igf1 (1.6 ± 7.6 vs. 0.9 ± 0.7, p = 0.002) and Ctgf (1.1 ± 2.1 vs. 0.6 ± 2.0, p = 0.013); and lower fold-change of Tgfβ1, Fgf7 and Glp2r. Conclusions: Those results underscore the recognized role of Igf1 and Hbegf as molecular mediators of the effects of teduglutide and suggest that other humoral factors, like Vegf and Ctgf, may also be relevant in the perioperative context. Induction of Vegfa, Igf1 and Ctgf gene expressions might indicate a favorable influence of teduglutide on the intestinal anastomotic healing.Introducción: teduglutida es un análogo intestinotrófico do péptido-2 similar al glucagón, con un mecanismo de acción indirecto y poco conocido, aprobado para la rehabilitación del síndrome de intestino corto. Este estudio propone analizar la respuesta de los factores de crecimiento tisulares a la agresión quirúrgica y a la administración de teduglutida en un modelo animal de anastomosis intestinal. Métodos: ratones Wistar (n = 59) fueron distribuidos en cuatro grupos: "resección ileal" o "laparotomía", cada uno subdividido en "administración post-operatoria de teduglutida" o "sin tratamiento"; y sacrificados en el tercero o el séptimo día, con recogida de muestras ileales. La expresión génica de Igf1, Vegfa, Tgfβ1, Ctgf, Fgf2, Fgf7, Egf, Hbegf, Pdgfb y Glp2r fue analizada por qRT-PCR. Resultados: en el segmento perianastomótico se verificó una sobrerregulación de Fgf7, Fgf2, Egf, Vegfa y Glp2r al tercer día y de Pdg al séptimo día. La administración de teduglutida se asoció con mayor cambio de la expresión génica relativa de Vegfa (3.6 ± 1.3 vs. 1.9 ± 2.0, p = 0.0001), Hbegf (2.2 ± 2.3 vs. 1.1 ± 0.9, p = 0.001), Igf1 (1.6 ± 7.6 vs. 0.9 ± 0.7, p = 0.002) y Ctgf (1.1 ± 2.1 vs. 0.6 ± 2.0, p = 0.013); y menor cambio de Tgfβ1, Fgf7 y Glp2r. Conclusiones: estos resultados refuerzan el reconocido papel de Igf1 y Hbegf como mediadores moleculares de los efectos de la teduglutida y sugieren que otros factores humorales, como Vegf y Ctgf, también pueden ser relevantes en el contexto perioperatorio. La inducción de las expresiones de los genes Vegfa, Igf1 y Ctgf podría indicar una influencia favorable de teduglutida en la cicatrización anastomótica intestinal

Evaluating the Impact of Different Hypercaloric Diets on Weight Gain, Insulin Resistance, Glucose Intolerance, and its Comorbidities in Rats

Animal experimentation has a long history in the study of metabolic syndrome-related disorders. However, no consensus exists on the best models to study these syndromes. Knowing that different diets can precipitate different metabolic disease phenotypes, herein we characterized several hypercaloric rat models of obesity and type 2 diabetes, comparing each with a genetic model, with the aim of identifying the most appropriate model of metabolic disease. The effect of hypercaloric diets (high fat (HF), high sucrose (HSu), high fat plus high sucrose (HFHSu) and high fat plus streptozotocin (HF+STZ) during different exposure times (HF 3 weeks, HF 19 weeks, HSu 4 weeks, HSu 16 weeks, HFHSu 25 weeks, HF3 weeks + STZ) were compared with the Zucker fatty rat. Each model was evaluated for weight gain, fat mass, fasting plasma glucose, insulin and C-peptide, insulin sensitivity, glucose tolerance, lipid profile and liver lipid deposition, blood pressure, and autonomic nervous system function. All animal models presented with insulin resistance and dyslipidemia except the HF+STZ and HSu 4 weeks, which argues against the use of these models as metabolic syndrome models. Of the remaining animal models, a higher weight gain was exhibited by the Zucker fatty rat and wild type rats submitted to a HF diet for 19 weeks. We conclude that the latter model presents a phenotype most consistent with that observed in humans with metabolic disease, exhibiting the majority of the phenotypic features and comorbidities associated with type 2 diabetes in humans

Impairment of the angiogenic process may contribute to lower success rate of endodontic treatments in diabetes mellitus

Aim: To investigate the association between root canal treatment outcome, diabetes mellitus, and alterations of the angiogenic process. Methodology: A retrospective observational study was conducted in healthy (control group, CG) and diabetic (type II diabetes mellitus group, DG) patients after root canal treatment. The follow-up appointments were performed to clinically and radiographically observe symptoms, the healing of periapical lesions, and the quality of root filling. In the animal model study, diabetic Goto-Kakizaki (GK) rats and control Wistar rats were used. After 21 days of pulp exposure and the development of apical periodontitis (AP), the mandibles were removed for scintigraphic, radiographic, histopathological and molecular analyses. Chi-square tests were performed to examine the variables related to endodontic outcome and differences between animal groups were assessed using the Student's t-test. Results: The group of patients with diabetes had a significantly lower rate of success following root canal treatment than the CG (p<0.001). Logistic regression suggested that diabetes is a risk factor for success of root canal treatment. In the animal study, GK rats had significantly higher fasting glycemia at t0 and t21 (p<0.001) and triglycerides levels (p<0.05) and area under the curve (AUC) during the insulin tolerance test at t21 (p<0.001). AP area was significantly greater in GK rats (p<0.05). Histologically, diabetic rats had increased signs of periodontal ligament inflammation 21 days after the induction of apical periodontitis, with fibro-hyaline matrix filling and vessel with undefined walls. Wistar rats had significantly increased vascular endothelial growth factor (VEGF) levels and VEGF/Ang-2 ratio 21 days after AP induction (p<0.08; p<0.07). GK rats had intrinsically lower levels of VEGF than control rats (p<0.05), which did not change after AP. Conclusion: Diabetes mellitus should be considered as an important factor in the prognosis of root canal treatment and its outcomes over time. Future strategies to improve angiogenesis and tissue repair should be pursued to achieve better root canal treatment outcomes in diabetic patient