Browsing by Author "Rodrigues, Alexandre"
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- SGLT2 Inhibitors: Novel approach to modulate appetite hormones and cardiomyocyte functionPublication . Correia, Beatriz; Rodrigues, Alexandre; Alves, Inês; Moraña-Fernández, Sandra; Mendes, Claúdia; Morais, Juliana; Gonçalves, Alexandre; Falcão-Pires, InêsEmerging as a class of oral antidiabetic drugs, sodium-glucose cotransporter 2 inhibitors (SGLT2i), used in patients with type 2 diabetes, offer promising results in weight loss, decreasing cardiometabolic biomarkers, thus improving overall cardiac function. The aim of this study is to assess whether SGLT2i can impact food and water consumption, hormone regulating appetite mechanisms, and morphologic parameters. Thirty-nine male ZSF1 rats were divided into two lean (Ln) and two obese (Ob) groups, fed with normal diet (ND) or treated with SGLT2i in food (30 mg/Kg/day). Body weight (BW), food, water, adiponectin and leptin were measured during nine weeks of treatment. Histochemistry analysis was performed with hematoxylin and eosin to determine the cross-section area in visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and cardiomyocytes. SGLT2i treatment promoted an increased food and water intake in lean rats (Ln_ SGLT2i). However, the BW in this group was markedly reduced compared with non-treated lean (Ln_ND). Furthermore, the treatment promoted higher water intake despite no differences in BW in obese rats (Ob_ SGLT2i) compared to control (Ob_ND). Exploring the hormone-regulating appetite mechanisms, SGLT2i treatment showed significant increased in adiponectin levels in both Ln and Ob, however leptin levels only validated the hyperleptinemia in Ob. The ratio adiponectin/leptin was markedly significant increase in Ln_ SGLT2i rats. At the endpoint, the treatment decreased perigonadal fat weight (PFW) in both groups. Aligned with these, cross-section areas of VAT, SAT and cardiomyocytes were markedly increased in Ob, and the treatment decreased these areas in Ob_ SGLT2i. SGLT2i treatment increased food and water intake as also the adiponectin/leptin ratio in Ln. Additionally, the treatment promoted PFW loss and increased the adiponectin levels in both groups and decreased the cross-section area of VAT, SAT, cardiomyocytes in Ob.
- Torus-breakdown near a heteroclinic attractor: a case studyPublication . Castro, Luísa; Rodrigues, AlexandreThere are few explicit examples in the literature of vector fields exhibiting observable chaos that may be proved analytically. This paper reports numerical experiments performed for an explicit two-parameter family of SO(2)⊕Z2𝕊𝕆(2)⊕ℤ2-symmetric vector fields whose organizing center exhibits an attracting heteroclinic network linking two saddle-foci. Each vector field in the family is the restriction to S3𝕊3 of a polynomial vector field in R4ℝ4. We investigate global bifurcations due to symmetry-breaking and we detect strange attractors via a mechanism called Torus-Breakdown. We explain how an attracting torus gets destroyed by following the changes in the unstable manifold of a saddle-focus. Although a complete understanding of the corresponding bifurcation diagram and the mechanisms underlying the dynamical changes is out of reach, we uncover complex patterns for the symmetric family under analysis, using a combination of theoretical tools and computer simulations. This article suggests a route to obtain rotational horseshoes and strange attractors; additionally, we make an attempt to elucidate some of the bifurcations involved in an Arnold tongue.