Table 4

MULTIPLE METABOLIC TOXICITIES IN MS AND T2DM: THE A-FLIGHT ACRONYM


Initiator
Metabolic Defect
Metabolic mediator
Functional mediator
Consequence

A
AMYLIN (Co-secreted – Co-packaged within the insulin secretory granule) by the islet Beta cell. Insulin's "Fraternal Twin" Elevated in MS, PD, and Early T2DM)
Hyperamylinemia
Activation of ANG II
PKC Signal Transduction Islet Amyloid IAPP Islet aggregation and deposition. Beta cell apoptosis – Beta cell defect.
ROS IAPP Amyloid in islets contributing to Beta Cell defect. Possible deposition in the intima, mesangium, neuronal unit, and myocardial. REMODELING

ANG II Via RAAS activation In MS, PD, and T2DM
Ang II Excess
Ang II Excess Most potent stimulus for: Activation of Vascular membrane bound NAD(P)H Oxidase Enzyme
PKC Signal Transduction. Superoxide production. Uncoupling of the eNOS reaction. TGF beta-1 activation
ROS NAD(P)H oxidase Derived Superoxide Myocardial, Renal, Intimal, Retinal, and Neuronal remodeling

AGE Advanced Glycation Endproducts AFE Advanced fructosylation endproducts
AGE / AFE See Glucotoxicity (G) RAGE activation Receptor for AGE
Protein Cross – linking / Dysfunction RAGE Receptor for AGE
Matrix Defects Signal Transduction Matrix Defects Signal Transduction
ROS Myocardial, Renal, Intimal, Retinal, Neuronal – Endoneurial Fibrosis

Advanced Lipoxidation Endproducts (ALE)
ALE
Protein Cross – linking
Matrix Defects Signal Transduction
ROS Matrix Remodeling

AntioxidantEnzymes: Antioxidant reserve compromised
Reduced – Dysfunctional eNOS, SOD, GPx, GSH, Catalase, and Vit. C.
Decreased NO
Decreased NO REDOX STRESS
ROS REDOX STRESS

AntioxidantEnzymes: Absence of antioxidant network
IMPAIRED eNOS L-arginine BH4
Decreased NO
Decreased NO
ROS Decreased NO

AGING: Accumulation of multiple metabolic toxicities → ROS
Increased Ox-LDL-C, TNFalpha, Capase 3, Glomerulosclerosis.
Decreased NO:
Decreased NO
ROS Inflammation, Apoptosis

Atherosclerotic Nephropathy
ROS beget ROS Atheroscleropathy
Decreased NO Self perpetuating Decreased NO
Decreased NO Athero – emboli Activated Platelets See Thrombotic Tox.
ROS beget ROS Decreased NO
F
Free fatty acid toxicity
Elevated FFA
LC acyl -CoA's
Mitochondrial Defects
ROS Cytotoxicity
L
Lipotoxicity Lipid Triad FFA ALE Long chain acyl-COA's
Increased VLDL – VLDL Triglycerides and Small dense atherogenic LDL-Cholesterol with Decreased HDL-Cholesterol LIPID TRIAD
LC acyl -CoA's Fat Accumulation
Non Adipose Accumulation of Fat (LC acyl -CoA's) in Adipose and Non Adipose Tissue
ROS Accumulation of fat in non adipose tissues resulting in Ceramide induced: Cytotoxicity
I
Insulin toxicity ENDOGENOUS Insulin Resistance
Hyperinsulinemia Hyperamylinemia in : MS, PD, EARLY T2DM Glut 4 is NO dependent Redox sensitive pathway
Ang II Increase # AT-1 receptors Cross-talk with AT-1 Increase FFA Increase PAI-1 Increase Sympathetic tone and activity Increased Na+ and H2O reabsorption Increase Volume and Blood Pressure Hypertension Hype
NAD(P)H REDOX STRESS SIGNAL PATHWAYS PI3 Kinase / Akt (Protein kinase B)→ MAP Kinase Shunt
ROS ROS ROS Extracellular Matrix Remodeling Islet, intimal, renal, myocardial, and neuronal.

Inflammation toxicity. "Inflammatory Cycle" (figure 5)
Activation of the innate immune system: IL-6, IL-8, TNF alpha Macrophage (MPO) → Hypochlorous Acid Superoxide O2
Acute Phase Reactants: C-Reactive Protein Serum Amyloid A Fibrinogen
NF kappa B Cellular Adhesion Molecules: ICAM, VCAM, and MCP-1
ROS Inflammation begets Inflammation " INFLAMMATORY CYCLE " (figure 5) ROS beget ROS

Insulin deficiency
OVERT T2DM
GLUCOTOXICITY POLYOL SORBITOL PATHWAY
REDUCTIVE STRESS NADH > NAD+ PSEUDOHYPOXIA
ROS
G
Glucotoxicity
Glycation / AGE
See above
See above
See above



Protein inactivation
Receptor-ligand defects
Dysfunctional Signal Transduction



NO quenching
Vasoconstriction
Ischemia/Hypoxia ROS



Macrophage Activation
Increased Cytokines, TGF-Beta
Cytotoxicity ROS



Free Radical Formation
REDOX STRESS
Cytotoxicity ROS


Auto-oxidation
Free Radical Formation
REDOX STRESS
Cytotoxicity ROS

ORIGIN OF REDUCTIVE STRESS ! REDUCTIVE STRESS !
Polyol Sorbitol Pathway (eNO inhibits Aldose Reductase)
Increased NADH Lactate Reductive Stress
REDOX STRESS Decreased NO Pseudohypoxia
Cytotoxicity ROS Ischemia/ Hypoxia



Decreased Taurine
REDOX STRESS
ROS Cytotoxicity


Increased DAG
Increased PKC
Signal Transduction
Ischemia ROS

Glucotoxicity
Glucotoxicity
Polyol – Sorbitol Pathway
PAS + material Interstitium, Basement Membrane
Remodeling – Cardiomyopathy CHF Diastolic Dysfunction
H
Hypertension Toxicity Homocysteine Toxicity
RAAS activation HHcy NO quenching and NEW: PPAR interaction.
Ang II Decreased GPx, DDAH with resultant ^ ADMA
NAD(P)H REDOX STRESS ^ ROS, O2', ONOO', nitrotyrosine
ROS Decreased NO, Endothelial Cell toxicity, dysfunction, and apoptosis
T
Triglyceride Toxicity Thrombotic Toxicity Taurine (antioxidant) depletion
Triglyceride – FFA exchange
See FFA – Lipotoxicity above eNOS uncoupling
REDOX STRESS Activated Platelets PAI-1 elevation Fibrinogen elevated. Decreased NO
ROS Athero-emboli ROS

Hayden and Tyagi Nutrition Journal 2004 3:4   doi:10.1186/1475-2891-3-4