Glucose Homeostasis

Glucose is the main and preferred source of energy for mammalian cells. Mammalian cells need glucose constantly. Long-lasting disturbances in blood glucose concentrations can cause diseases and death. Therefore, blood glucose concentrations must be within narrow limits. The process of maintaining blood glucose at a steady-state level is called glucose homeostasis

Distribution of glucose transporters in renal diseases

Abstract Kidneys play an important role in glucose homeostasis. Renal gluconeogenesis prevents hypoglycemia by releasing glucose into the blood stream. Glucose homeostasis is also due, in part, to reabsorption and excretion of hexose in the kidney. Lipid bilayer of plasma membrane is impermeable for glucose, which is hydrophilic and soluble in water. Therefore, transport of glucose across the plasma membrane depends on carrier proteins expressed in the plasma membrane. In humans, there are three families of glucose transporters: GLUT proteins, sodium-dependent glucose transporters (SGLTs) and SWEET. In kidney, only GLUTs and SGLTs protein are expressed. Mutations within genes that code these proteins lead to different renal disorders and diseases. However, diseases, not only renal, such as diabetes, may damage expression and function of renal glucose transporters

Brain Glucose Transporters: Role in Pathogenesis and Potential Targets for the Treatment of Alzheimer’s Disease

The most common cause of dementia, especially in elderly people, is Alzheimer’s disease (AD), with aging as its main risk factor. AD is a multifactorial neurodegenerative disease. There are several factors increasing the risk of AD development. One of the main features of Alzheimer’s disease is impairment of brain energy. Hypometabolism caused by decreased glucose uptake is observed in specific areas of the AD-affected brain. Therefore, glucose hypometabolism and energy deficit are hallmarks of AD. There are several hypotheses that explain the role of glucose hypometabolism in AD, but data available on this subject are poor. Reduced transport of glucose into neurons may be related to decreased expression of glucose transporters in neurons and glia. On the other hand, glucose transporters may play a role as potential targets for the treatment of AD. Compounds such as antidiabetic drugs, agonists of SGLT1, insulin, siRNA and liposomes are suggested as therapeutics. Nevertheless, the suggested targets of therapy need further investigations

Insulin Resistance: The Increased Risk of Cancers

Insulin resistance, also known as impaired insulin sensitivity, is the result of a decreased reaction of insulin signaling to blood glucose levels. This state is observed when muscle cells, adipose tissue, and liver cells, improperly respond to a particular concentration of insulin. Insulin resistance and related increased plasma insulin levels (hyperinsulinemia) may cause metabolic impairments, which are pathological states observed in obesity and type 2 diabetes mellitus. Observations of cancer patients confirm that hyperinsulinemia is a major factor influencing obesity, type 2 diabetes, and cancer. Obesity and diabetes have been reported as risks of the initiation, progression, and metastasis of several cancers. However, both of the aforementioned pathologies may independently and additionally increase the cancer risk. The state of metabolic disorders observed in cancer patients is associated with poor outcomes of cancer treatment. For example, patients suffering from metabolic disorders have higher cancer recurrence rates and their overall survival is reduced. In these associations between insulin resistance and cancer risk, an overview of the various pathogenic mechanisms that play a role in the development of cancer is discussed

Adipose Tissue

Adipose tissue is a specialized connective tissue which, depending on type, plays different and significant roles in the human body: protects against environmental factors, stores lipids and triacylglycerol, synthesizes fatty acids and is involved in the process of thermogenesis. It is also a major secretory organ and highly active metabolic tissue. It secretes, for example, cholesterol, retinol, steroid hormones, prostaglandins and proteins known as ""adipokines"". Some of these molecules may be associated with pathologies such as obesity and insulin resistance. In humans, there are two main sites of adipose tissue accumulation: visceral and subcutaneous. Obesity is a worldwide health problem. This book also discusses a series of up-to-date topics about this pathology

Glucose transporters as markers of diagnosis and prognosis in cancer diseases

Glucose is a main metabolic substrate, which plays a role as a source of energy and a substrate in several processes. Cell membrane is lipophilic, whereas monosaccharides are hydrophilic. Therefore, lipid bilayer is impermeable for these substances and they need specific carrier proteins. Glucose metabolism in cancer cells differs from this process in normal cells. Cancer cells prefer the process of glycolysis, which generates less molecules of ATP than complete oxidative breakdown, therefore cancer cells need more molecules of glucose. Increased uptake of glucose is due to changes in expression of glucose transporters. Several glucose transporters are overexpressed in cancer cells, however, there are also observed decreased levels of these proteins in cancer cells. There are observed specific correlations between cancer and expression of glucose carrier proteins. Therefore, changes in expression of glucose transporters in cancers may be treated as a marker of diagnosis and/or prognosis for cancer patients