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