Oxidative stress and caloric restriction
Jan ŠkrhaProfessor of Medicine
3rd Department of Internal Medicine,
Laboratory for Endocrinology & Metabolism
1st Faculty of Medicine,
Charles University, Prague
IFCC Congress, Berlin 2011
OBESITY AND CONSEQUENCES
Overeating
Weight increase
Higher concentration of circulating FFA
Insulin resistance
Hyperinzulinemia
ROS
FFA – GENERATOR OF INSULIN RESISTANCE AND OXIDATIVE STRESS
Insulin FFA
IRS-1 phosphoryl. serine/threonine FA-CoA
IRS-1 phosphoryl. tyrosine DAG
PKC ROS
PI-3-kinase
NFĸB activation
GLUT 4 translocation ROS
glucose transport inflammatory proteins
Diabetes Care 27, 2004, 2253-9
I
IIQ-
III IVcyt c
e-e-e-
e-
Succinate
Fumarate
NAD+ NADH
H2O+O2 O2- O2
Mn-SOD
O2
H2OATP ADP + P
UCP
H+ H+ H+ H+ H+
H+ gradient generation Decrease of H+gradient
SUPEROXIDE GENERATION IN MITOCHONDRIA
Respiratory chain
Substratesupply
Glucose
GAPDH
Polyols AGE PKC Hexosamine
NFκB
Mitochondria
Nucleus
Cytoplasm
M.Brownlee, Diabetes 2005
UNIFYING MECHANISM FOR IMPAIRMENT CAUSED BY HYPERGLYCEMIA AND FFA
FFA
PARP
ROS
ENDOTHELIAL CELLHyperglycemia
Intracellular glucose
Reactive oxygen species in mitochondria
polyols lipoxidationglycation PKCß hexosamines glycoxidation
Endothelial dysfunction
DIABETIC ANGIOPATHY
oxidative stress
GLUT 1
EXOGENOUS AGE´s ACCELERATE OXIDATIVE STRESS
EXOGENOUS AGEs
NITROSATIVE STRESS
Endothelial dysfunction
MODULATION OF OXIDATIVE STRESS BY CALORIC INTAKE
I
IIQ-
III IVcyt c
e-e-e-
e-
Succinate
Fumarate
NAD+ NADH
H2O+O2 O2- O2
Mn-SOD
O2
H2OATP ADP + P
UCP
H+ H+ H+ H+ H+
H+ gradient generation Decrease of H+gradient
REDUCED SUPEROXIDE GENERATION IN MITOCHONDRIA
Respiratory chain
Decreasedsubstratesupply
Gredilla et al., FASEB J 2001
Sirtuins – caloric restriction effectors(silent information regulators – SIRT1-7)
family: NAD-dependent histone deacetylases
- influencing aging, metabolic processes, tumorigenesis
Reduced caloric intake: SIRT1 upregulation increases gluconeogenesis decreases adipocyte formation
oposite to insulin
sirtuins like „molecular sensor“
Activators Inhibitors
• increase life span and cell survival• promote fat mobilization• increase the mitochondria number
• stop tumor formation• stop apoptosis• stop neurodegenerative disease
Sirtuins – key regulators of oxidative stress
increase of antioxidative defense: by upregulated MnSOD expression by reduced cellular hydrogen peroxide by enhanced mitochondrial glutathion capacity
reduced mitochondrial ROS production
Caloric restriction vs dietary composition
• reduced activity of complex I • restriction of protein intake vs complex III in mitochondria (methionine content) decreased ROS production
Crujeiras et al., Europ J Clin Invest 2008, Someya et al., Cell 2010, Sanz et al., J Bioenerg Biomembr 2004
Caloric restriction vs fasting
Caloric restriction and short intermitent fasting
Prolonged fasting
beneficial effects:
decreased ROS productionmitochondrial protection
harmful effects:
superoxide anion release from hepatocytesdecreased glutathione content
Resistance to oxidative stress
increased decreased
Mattson et al., J Nutr Biochem 2005 Sorensen et al., Free Radic Res 2006
BIOMARKERS
Biomarker Caloric restriction
Lipid peroxidation Malondialdehyde (MDA) decreased F-2-isoprostanes decreased
Nitrosative stress Nitrotyrosine decreased
DNA damage 8-hydroxydeoxy-guanosine decreased
Scavanger enzymes SOD decreased, no change, increased CAT decreased, no change, increased GPx inverse relationship to CAT GR Non-enzymatic scavengers GSH GSH/GSSG ratio increased Ascorbic acid no changes or increased α-tocopherol no changes (α-toc/chol+tg)
Increased oxidative stress
Reduced oxidative stress
Cycling of OX/RED forms
Comparison of the oxidative stress measures by obese and nonobese
persons
0
0,5
1
1,5
2
2,5
3
3,5
MD
A (m m
ol/
l)
MS
C
p<0,0010
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
SO
D (
U)
MS
C
p<0,01
0
5
10
15
20
25
Glu
tath
ion
(mm
ol/
l) MS
C
p<0,01
OXIDATIVE STRESS IN OBESE SUBJECTS
0
10
20
30
40
50
60
70
80
90
100
Asc
orb
ic a
cid
(m m
ol/l
)
MS
C
p<0,010
5
10
15
20
25
a-T
oco
ph
ero
l (m
g/l)
MS
C
p<0,01
0
0,5
1
1,5
2
2,5
aT
/(C
H+
T)
(mg
/mm
ol) MS
C
p<0,01
OXIDATIVE STRESS IN OBESE SUBJECTS
0
1
2
3
4
5
6
7
CR
P (
mg
/l)
MS
C
p<0,051
100
10000
log
an
tio
x L
DL
(m
U/m
l)
MS
C
p<0,05
OXIDATIVE STRESS IN OBESE SUBJECTS
DECREASED CALORIC INTAKE(for obese or overweight individuals)
diabetic rats Wistar: 9 wks fed: group A – hypocaloric diet group B – free diet
in group A: decreased TNF-α, IL-1, IL-4, IL-6 increased antiinflammatory mediators and IL-10
Prevention of diabetic complications by supression of inflammation due to decreased oxidative stress
Ugochukwu et al., J Nutr Biochem 2007, 18, 120-126
COMBINATION OF DIET AND PHYSICAL ACTIVITY
Roberts CK et al., Atherosclerosis 191, 2007, 98-106
Improved lifestyle in 19 children with overweight
2 wks: diet with reduced fat + increased fiber contents 2hrs daily physical training
Results: decrease: cholesterol, TG, 8-iso-PGF-2, ICAM-1, selectin, CRP, myeloperoxidase, superoxide and H2O2
increase: NO
Improved parameters associated with atherosclerosis risk
CALORIC RESTRICTION & OXIDATIVE STRESS
Patients:
A/ obese Type 2 diabetic patients (n=9)
B/ obese non-diabetic patients (n=9)
Methods:
VLCD diet (600 kcal), 1 week
Laboratory methods:
FFA, ß-HB, MDA, SOD, ascorbic acid, alpha-tocopherol, T-chol, HDL, LDL-chol., TG
CALORIC RESTRICTION & OXIDATIVE STRESS
Diabetic pts: Age 55 (41-70) yrs.
DM duration 12 ± 5 r.
BMI 36.2 ± 1.6 kg/m2
HbA1c 10.2 ± 1.6 %
Controls: Age 53 (35-69) r.
BMI 37 ± 2.1 kg/m2
HbA1c 5.5 ± 0.4 %
0
2
4
6
8
10
12
14
16
Diabetic patients Control pesons
FP
G (
mm
ol/
l)
Before
Day 8
0,001
Low-calory diet
Control persons
00,5
11,5
22,5
33,5
4
Diabetic patients Control pesons
LD
L-c
ho
l (m
mo
l/l)
BeforeDay 8
0,05 0,001
Low-calory diet
Control persons
00,20,40,60,8
11,21,41,6
Diabetic patients Control pesons
HD
L-c
ho
l (m
mo
l/l)
BeforeDay 8
0,001 0,001
Low-calory diet
Control persons
0
0,5
1
1,5
2
2,5
3
Diabetic patients Control pesons
Tri
gly
ce
rid
es
(m
mo
l/l)
BeforeDay 8
0,001 0,05
Low-calory diet
Control persons
0
0,5
1
1,5
2
2,5
3
Diabetic patients Control pesons
MD
A (m
mo
l/l)
BeforeDay 8
0,01
Low-calory diet
Control persons
0
0,2
0,4
0,6
0,8
1
Diabetic patients Control pesons
SO
D (
U)
BeforeDay 8
0,01 0,01
Low-calory diet
Control persons
5254
565860
6264
6668
Diabetic patients Control pesons
Asc
orb
ic a
cid
(m
mo
l/l)
BeforeDay 8
0,01
Low-calory diet
Control persons
1,5
1,55
1,6
1,65
1,7
1,75
1,8
1,85
Diabetic patients Control pesons
aT
/(C
h+
T)
(mg
/mm
ol)
BeforeDay 8
0,05
Low-calory diet
CALORIC RESTRICTION & OXIDATIVE STRESS
Conclusions1. Caloric restriction lowers LDL and HDL-cholesterol
and triglycerides
2. Significant decrease of oxidative stress was found in obese non-diabetic pts (MDA decrease, SOD and ascorbic acid increase), these changes were only borderline in diabetic patients
3. Obese diabetic patients are more resistant to low calory diet in comparison with obese non-diabetic patients and they reduce oxidative stress less than non-diabetic persons
a) Oxidative stress is higher in obese than in nonobese persons b) Very low calory diet decreases the level of oxidative stress
Thank you