Intensified glycemic control is now recommended as the standard of care for all patients with diabetes. Unfortunately, the major barrier to achieving normoglycemia in patients with diabetes is hypoglycemia. Further complicating management of patients with diabetes is that the therapeutic cornerstone of exercise also contributes to increased hypoglycemia. Many studies have identified that intensive glycemic control can result in acquired failure of neuroendocrine and importantly autonomic nervous system (ANS) counterregulatory responses during hypoglycemia. Recent work has also demonstrated that episodes of both antecedent hypoglycemia and exercise can result in reciprocal, subsequent ANS counterregulatory dysfunction during either stress. The mechanisms responsible for prior hypoglycemia and/or exercise resulting in ANS counterregulatory dysfunction have yet to be determined. Recent interest has begun to be focused on central nervous system (CNS) regulation of physiologic responses during exercise and hypoglycemia. Currently, there are no adjunct treatments that protect the ANS from the deleterious effects of repeated episodes of hypoglycemia. In this application, we will propose therapeutic interventions aimed at reversing the central mechanisms that result in hypoglycemia associated autonomic dysfunction (HAAD). Atherothrombosis is a major cause of morbidity and mortality in patients with type 2 diabetes (T2DM). Recent large clinical trials have highlighted the association between hypoglycemia and increased mortality in T2DM. Of concern is the lack of information regarding the physiologic effects of ANS activation on endothelial function and atherothrombofic balance during hypoglycemia in diabefic individuals. Studies oufiined in this proposal are therefore focused at determining the in-vivo mechanisms regulating ANS counterregulatory responses and in-vivo vascular and metabolic effects during hypoglycemia and exercise in healthy and diabefic humans. Experiments will use the glucose and pancreafic clamp techniques to control glucose levels and glucoregulatory hormones. ANS responses to hypoglycemia will be assessed by measuring circulating catecholamines, pancreatic polypepfide, muscle sympathefic nerve acfivity (MSNA), symptom scores and heart rate variability. Neuroendocrine responses will be determined by measuring growth hormone, Cortisol and glucagon levels. Metabolic counterregulatory mechanisms will be quantified by measuring glucose turnover, lipolysis and substrate oxidafion via indirect calorimetry. Nitric oxide and non-nitric oxide dependent endothelial arterial funcfion will be determined by flow mediated vasodilafion, vascular atherothrombotic balance will be determined by PAl-1, TPA, P-selecfin and adhesion molecule levels.

Public Health Relevance

Cardiovascular disease is a major cause of morbidity and mortality in individuals with diabetes. Recently, large multi-center randomized controlled trials have reported an associafion between hypoglycemia and serious cardiovascular events and death in type 2 diabetes. This application will determine in-vivo mechanisms responsible for hypoglycemia associated adverse cardiac events and propose novel treatments to prevent this occurrence.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
2P01HL056693-16
Application #
8293462
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2012-05-01
Budget End
2013-04-30
Support Year
16
Fiscal Year
2012
Total Cost
$299,355
Indirect Cost
$14,000
Name
Vanderbilt University Medical Center
Department
Type
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Biaggioni, Italo; Calhoun, David A (2016) Sympathetic Activity, Hypertension, and The Importance of a Good Night's Sleep. Hypertension 68:1338-1339
Harder, René; Malow, Beth A; Goodpaster, R Lucas et al. (2016) Heart rate variability during sleep in children with autism spectrum disorder. Clin Auton Res 26:423-432
Mar, Philip L; Nwazue, Victor; Black, Bonnie K et al. (2016) Valsalva Maneuver in Pulmonary Arterial Hypertension: Susceptibility to Syncope and Autonomic Dysfunction. Chest 149:1252-60
Shibao, Cyndya A; Celedonio, Jorge E; Ramirez, Claudia E et al. (2016) A Common CD36 Variant Influences Endothelial Function and Response to Treatment with Phosphodiesterase 5 Inhibition. J Clin Endocrinol Metab 101:2751-8
Adefurin, Abiodun; Darghosian, Leon; Okafor, Chimalum et al. (2016) Alpha2A adrenergic receptor genetic variation contributes to hyperglycemia after myocardial infarction. Int J Cardiol 215:482-6
Raj, Satish R (2016) Row, row, row your way to treating postural tachycardia syndrome. Heart Rhythm 13:951-2
Joy, Nino G; Perkins, Jennifer M; Mikeladze, Maia et al. (2016) Comparative effects of acute hypoglycemia and hyperglycemia on pro-atherothrombotic biomarkers and endothelial function in non-diabetic humans. J Diabetes Complications 30:1275-81
Lateef, Dalya M; Xiao, Cuiying; Brychta, Robert J et al. (2016) Bombesin-like receptor 3 regulates blood pressure and heart rate via a central sympathetic mechanism. Am J Physiol Heart Circ Physiol 310:H891-8
Harder, Rene; Diedrich, Andre; Whitfield, Jonathan S et al. (2016) Smart Multi-Frequency Bioelectrical Impedance Spectrometer for BIA and BIVA Applications. IEEE Trans Biomed Circuits Syst 10:912-9
Iwuchukwu, Otito F; Ramirez, Andrea H; Shi, Yaping et al. (2016) Genetic determinants of variability in warfarin response after the dose-titration phase. Pharmacogenet Genomics 26:510-516

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