Special Issue "Glucose Sensors"

Guest Editor
Dr. Mike McShane
Texas A&M University, Department of Biomedical Engineering, Mailstop 3120, College Station, TX 77843-3120, USA
Website: http://biomed.tamu.edu/biominds/index.php
E-Mail:
Interests: biomedical sensing and imaging; biomaterials; nanotechnology; biomedical optics; medical devices

Submission

Type of Paper: Review
Title: Adenosine Monophosphate-Activated Protein Kinase (AMPK): A
Cellular Metabolic and Redox Sensor: A Minireview
Authors: Najeeb Shiwany and Ming-Hui Zou
Affiliation: Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK 73013, USA; E-Mail: Ming-Hui-Zou@ouhsc.edu (M.-H.Z.)
Abstract: AMPK is an enzyme that plays a key role in cellular energy homeostasis. The net effect of AMPK activation, which occurs when the AMP:ATP ratio is elevated, is to initiate steps to conserve energy and restore the energy balance of the cell. It has therefore been called the cellular "master switch". However, it also appears to act as a redox sensor, particularly in vascular endothelial cells. In these cells, oxidative stress can disturb NO signaling. By inhibiting the formation of reactive oxygen species in the endothelium, AMPK can return the endothelium toward optimum redox balance. Here, we review the role of AMPK in the cell, examine its upstream and downstream signaling partners, assess its role as a sensor capable of integrating diverse responses at the cellular and whole body level and define its potential as a novel therapeutic target.

Type of Paper: Review
Title: Hypothalamic Glucose Sensing Neurons
Author: Vanessa H. Routh
Affiliation: Department of Pharmacology & Physiology, UMDNJ - New Jersey Medical School, Medical Sciences Building, I619, Labs: I628, I675 & I671, 185 S. Orange Avenue, Newark , NJ 07103, USA; E-Mail: routhvh@umdnj.edu
Abstract: Glucose-excited (GE) neurons increase while glucose-inhibited (GI) neurons decrease their action potential frequency as extracellular brain glucose levels increase. We hypothesize that these neurons evolved to sense and respond to severe energy deficit (e.g., fasting) that threatens the brains glucose supply. During modern times, they are also important for the restoration of blood glucose levels following insulin-induced hypoglycemia. Our data suggest that impaired glucose sensing by hypothalamic glucose sensing neurons may contribute to impaired detection of energy or glucose deficit. On the other hand, increased responses of hypothalamic glucose sensing neurons to glucose deficit may play a role in the development of Type 2 Diabetes Mellitus and obesity. This review will discuss the mechanisms by which hypothalamic glucose sensing neurons sense changes in extracellular glucose and explore the roles of these specialized glucose sensors in glucose and energy homeostasis.

Title: Ag Nanoparticles Capped by a Nontoxic Polymer: Electrochemical and Spectroscopic Characterization of a Novel Nanomaterial for Glucose Detection
Authors: Maria Rachele Guascito, Daniela Chirizzi, Cosimino Malitesta, Elisabetta Mazzotta, Rosaria Anna Picca
Affiliation: Laboratorio di Chimica Analitica, Dipartimento di Scienza dei Materiali, Università del Salento, Via per Monteroni - Palazzina M, 73100 Lecce, Italy; E-Mail: maria.rachele.guascito@unisalento.it
Abstract: Modified electrodes with metal or metal oxides nanoparticles are particularly appealing to improve sensor performances and fabricate miniaturized devices, as required also in glucose detection. A Pt electrode modified by drop casting of a novel nanostructured film based on silver nanoparticles (Ag NPs) capped in a commercial nontoxic polyvinyl alcohol (PVA) matrix is proposed here as a valid alternative to classical glucose (bio)sensors. The extensive electrochemical and spectroscopic characterization by X-ray Photoelectron Spectroscopy (XPS) of this advanced nanomaterial is presented to study its response to glucose and to investigate the chemical nature of deposited Ag.

Type of Paper: Review
Title: Sensors in Glucose Monitoring in Diabetes Mellitus
Authors: Isabel Torres, Maria Gloria Baena, Manuel Cayon, Jose Ortego-Rojo and Manuel Aguilar-Diosdado.
Affiliation: Endocrinology and Nutrition Service, Hospital Puerta del Mar, Ana de Viya, 21, 11009 Cadiz, Spain; E-Mail: manuel.aguilar.sspa@juntadeandalucia.es (M.A.-D.)
Abstract: Glucose control is the cornerstone of diabetes treatment. Although self monitoring blood glucose (SMBG) still remains the best procedure in clinical practice, continuous glucose monitoring systems (CGMS) offer the possibility of continuous and dynamics assessment of interstitial glucose concentration. CGMS have the potential to improve glycemic control while decreasing the incidence of hypoglycaemia but the efficiency, compared with SMBG, is not certain. CGMS has the greatest potential value in patients with hypoglycemic unawareness and in controlling daily fluctuations in blood glucose. The implementation of continuous monitoring in the clinical setting has not yet been established but a new generation of open a close loop subcutaneous insulin-infusion devices are emerging making more reliable insulin treatment and glycaemic control.

Title: Models of Transporter-like Sensors for Glucose and Other Nutrients
Authors: Kaisa Karhumaa and Morten C. Kielland-Brandt
Affiliation: Center for Microbial Biotechnology, Department of Systems Biology, Technical University of Denmark, Denmark; E-Mail: kka@bio.dtu.dk (K.K.)
Abstract: Baker’s yeast Saccharomyces cerevisiae has been adapted for growth in high glucose and sucrose concentrations during thousands of years of human use. Several regulatory systems enable the cell to respond to changes in the concentrations of sugar and other nutrients in the immediate environment. Yeast harbours sensors for extracellular nutrients, such as glucose, on the cell surface. The sensors may be divided into two groups: transporter-like sensors, which structurally resemble transporters of the corresponding nutrient, and the sensor Gpr1, which belongs to the widely occurring G-protein-coupled receptors. Transporter-like glucose sensors Snf3 and Rgt2 do not transport glucose and function mainly in the regulation of hexose transporter gene expression. Similarly, transporter-like amino acid sensor Ssy1 is unable to transport leucine, its most potent elicitor. In other cases, bona fide nutrient transporters, such as amino acid transporter Gap1 and phosphate transporter Pho84, have dual transport and sensing function. Binding of the respective elicitors to transporter-like sensors appears to promote and/or stabilise a conformation of the sensor that activates a signal transduction pathway downstream. Models of the molecular mechanism of signalling through transporter-like sensors have been suggested and tested. The results are consistent with a function similar to the alternate access model for nutrient transport.