The sphingosine-1-phosphate receptor modulator, FTY720, prevents the incidence of diabetes in Spontaneously Diabetic Torii rats

Therapeutic Potential of Fingolimod in Diabetes Mellitus and Its Chronic Complications

Diabetes mellitus is a metabolic disease characterized by elevated blood glucose due to a deficiency of insulin secretion and/or action. Long-term poor blood glucose control may lead to chronic damage and dysfunction of the heart, kidneys, eyes, and other organs. Therefore, it is important to develop treatments for diabetes and its chronic complications. Fingolimod is a structural sphingosine analogue and sphingosine-1-phosphate receptor modulator currently used for the treatment of relapsing-remitting multiple sclerosis. Several studies have shown that it has beneficial effects on the improvement of diabetes and its chronic complications. This paper reviews the therapeutic potential of Fingolimod in diabetes and its chronic complications, aiming to further guide future treatment strategies.

Rodent Models of Diabetic Retinopathy as a Useful Research Tool to Study Neurovascular Cross-Talk

Diabetes is a group of metabolic diseases leading to dysfunction of various organs, including ocular complications such as diabetic retinopathy (DR). Nowadays, DR treatments involve invasive options and are applied at the sight-threatening stages of DR. It is important to investigate noninvasive or pharmacological methods enabling the disease to be controlled at the early stage or to prevent ocular complications. Animal models are useful in DR laboratory practice, and this review is dedicated to them. The first part describes the characteristics of the most commonly used genetic rodent models in DR research. The second part focuses on the main chemically induced models. The authors pay particular attention to the streptozotocin model. Moreover, this section is enriched with practical aspects and contains the current protocols used in research in the last three years. Both parts include suggestions on which aspect of DR can be tested using a given model and the disadvantages of each model. Although animal models show huge variability, they are still an important and irreplaceable research tool. Note that the choice of a research model should be thoroughly considered and dependent on the aspect of the disease to be analyzed.

Sphingosine-1-phosphate in mitochondrial function and metabolic diseases

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite. The past decade has witnessed exponential growth in the field of S1P research, partly attributed to drugs targeting its receptors or kinases. Accumulating evidence indicates that changes in the S1P axis (i.e., S1P production, transport, and receptors) may modify metabolism and eventually mediate metabolic diseases. Dysfunction of the mitochondria on a master monitor of cellular metabolism is considered the leading cause of metabolic diseases, with aberrations typically induced by abnormal biogenesis, respiratory chain complex disorders, reactive oxygen species overproduction, calcium deposition, and mitophagy impairment. Accordingly, we discuss decades of investigation into changes in the S1P axis and how it controls mitochondrial function. Furthermore, we summarize recent scientific advances in disorders associated with the S1P axis and their involvement in the pathogenesis of metabolic diseases in humans, including type 2 diabetes mellitus and cardiovascular disease, from the perspective of mitochondrial function. Finally, we review potential challenges and prospects for S1P axis application to the regulation of mitochondrial function and metabolic diseases; these data may provide theoretical guidance for the treatment of metabolic diseases.

Immune Disorders and Sex Differences in Spontaneously Diabetic Torii Rats, Type 2 Diabetic Model

Type 2 diabetes (T2D) is believed to be a non-autoimmune metabolic disorder. However, there are increasing reports that some T2D patients have immune abnormalities. In addition, it is known that there are sex differences in the onset of diabetes and immune responses in humans. Spontaneously Diabetic Torii (SDT) rats, a non-obese T2D model, also have sex differences in the onset of diabetes, but the involvement of immune abnormalities in diabetes is unknown. In this study, we investigated immune abnormalities in SDT rats. Immune cell subset analysis was performed in male and female SDT rats and control Sprague-Dawley (SD) rats at 5, 11, and 17 weeks of age. Male and female SDT rats had swelling of the spleen and lymph nodes and a higher number of T cells and B cells in the blood, spleen, and lymph nodes than SD rats. Only male SDT rats developed diabetes at 17 weeks of age, and the number of classical and non-classical monocytes in the blood and spleen of male SDT rats was higher than that in male SD rats and female SDT rats that did not develop diabetes. Most of these findings were observed before the onset of diabetes (~11 weeks of age), suggesting that classical and non-classical monocytes may contribute to the development of diabetes in male SDT rats. In conclusion, SDT rats may be a useful T2D model involved in immune abnormalities, and further research will help elucidate the pathophysiology of T2D with immune abnormalities and develop new therapeutic agents.

Cellular mechanisms and recommended drug-based therapeutic options in diabetic cardiomyopathy

Diabetes mellitus (DM) is associated with a specific cardiac phenotype characterized by structural and functional alterations. This so-called diabetic cardiomyopathy (DM CM) is clinically relevant as patients with DM show high incidence of heart failure. Mechanistically, several parameters interact on the cardiomyocyte level leading to increased inflammation, apoptosis, reactive oxygen species and altered calcium signaling. This in turn provokes functional myocardial changes that might inter alia play into the worsened clinical outcome in DM patients. Therefore, efficient therapeutic options are urgently needed. This review focuses on mechanistic effects of currently recommended antidiabetic treatment and heart failure therapy for DM CM.

Adipocyte-Derived Extracellular Vesicles: State of the Art

White adipose tissue (WAT) is involved in long-term energy storage and represents 10–15% of total body weight in healthy humans. WAT secretes many peptides (adipokines), hormones and steroids involved in its homeostatic role, especially in carbohydrate–lipid metabolism regulation. Recently, adipocyte-derived extracellular vesicles (AdEVs) have been highlighted as important actors of intercellular communication that participate in metabolic responses to control energy flux and immune response. In this review, we focus on the role of AdEVs in the cross-talks between the different cellular types composing WAT with regard to their contribution to WAT homeostasis and metabolic complications development. We also discuss the AdEV cargoes (proteins, lipids, RNAs) which may explain AdEV’s biological effects and demonstrate that, in terms of proteins, AdEV has a very specific signature. Finally, we list and suggest potential therapeutic strategies to modulate AdEV release and composition in order to reduce their deleterious effects during the development of metabolic complications associated with obesity.