Dietary krill oil (Euphausia superba) alleviates oxidative stress and DNA damages bio-markers in an experimental model of cafeteria diet-induced insulin resistance in rats

Insulin resistance (IR) may be associated with oxidative stress and leads to cardiovascular disorders. Current research focuses on interplay between insulin-resistance indices and oxidant-antioxidant markers in elderly individuals with or without insulin-resistance. The assessment involved anthropometric data (weight, height, BMI, percentage of body fat (FAT)) and biochemical tests (glucose, lipids, serum insulin and plasma oxidant-antioxidant markers: Thiobarbituric Acid-Reacting Substances (TBARS), Cu,Zn-superoxide dismutase (SOD-1) and total antioxidant status). Insulin resistance index (IR) assuming a cut-off point of 0.3 allows to divides groups into: insulin sensitive group (InsS) IR < 0,3 ( n = 35, median age 69.0 years) and insulin-resistant group (InsR) IR ≥ 0.3 ( n = 51, median age 71.0 years). Lipids and antioxidant defense system markers did not differentiate the investigated groups. In the InsR elderly group, the FAT was increased ( P < 0.000003) and TBARS ( P = 0.008) concentration decreased in comparison with InsS group. A positive correlation for SOD-1 and total antioxidant status ( P < 0.05; r = 0.434) and a negative correlation for TBARS and age ( P < 0.05 with r = −0.421) were calculated in InsR individuals. In elderly individuals, oxidative stress persists irrespective of insulin-resistance status. We suggest that increased oxidative stress may be consequence of old age. An insulin action identifies those at high risk for atherosclerosis, via congruent associations with oxidative stress and extra- and intra-cellular antioxidant defense systems. Thus, we maintain that insulin-resistance is not the cause of aging. Impact statement Insulin resistance is associated with oxidative stress leading to cardiovascular diseases. However, little research has been performed examining elderly individuals with or without insulin-resistance. We demonstrate that antioxidant defense systems alone is not able to abrogate insulin action in elderly individuals at high risk for atherosclerosis, whereas the combined oxidant-antioxidant markers (thiobarbituric acid-reacting substances (TBARS), Cu,Zn-superoxide dismutase (SOD-1), and total antioxidant status (TAS)) might be more efficient and perhaps produce better clinical outcome. In fact, a decrease in oxidative stress and strong interaction between antioxidant defense can be seen only among insulin-resistant elderly individuals. This is, in our opinion, valuable information for clinicians, since insulin-resistance is considered strong cardiovascular risk factor.

Download Full-text

Nitric oxide synthase 3 deficiency limits adverse ventricular remodeling after pressure overload in insulin resistance

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00744.2010 ◽

2011 ◽

Vol 301 (5) ◽

pp. H2093-H2101 ◽

Cited By ~ 5

Author(s):

Baptiste Kurtz ◽

Helene B. Thibault ◽

Michael J. Raher ◽

John R. Popovich ◽

Sharon Cawley ◽

...

Keyword(s):

Oxidative Stress ◽

Nitric Oxide ◽

Insulin Resistance ◽

Mitochondrial Respiration ◽

Pressure Overload ◽

Lv Remodeling ◽

Stress Levels ◽

Nitric Oxide Synthase 3 ◽

And Function ◽

Oxide Synthase

Insulin resistance (IR) and systemic hypertension are independently associated with heart failure. We reported previously that nitric oxide synthase 3 (NOS3) has a beneficial effect on left ventricular (LV) remodeling and function after pressure-overload in mice. The aim of our study was to investigate the interaction of IR and NOS3 in pressure-overload-induced LV remodeling and dysfunction. Wild-type (WT) and NOS3-deficient (NOS3−/−) mice were fed either a standard diet (SD) or a high-fat diet (HFD) to induce IR. After 9 days of diet, mice underwent transverse aortic constriction (TAC). LV structure and function were assessed serially using echocardiography. Cardiomyocytes were isolated, and levels of oxidative stress were evaluated using 2′,7′-dichlorodihydrofluorescein diacetate. Cardiac mitochondria were isolated, and mitochondrial respiration and ATP production were measured. TAC induced LV remodeling and dysfunction in all mice. The TAC-induced decrease in LV function was greater in SD-fed NOS3−/− mice than in SD-fed WT mice. In contrast, HFD-fed NOS3−/− developed less LV remodeling and dysfunction and had better survival than did HFD-fed WT mice. Seven days after TAC, oxidative stress levels were lower in cardiomyocytes from HFD-fed NOS3−/− than in those from HFD-fed WT. Nω-nitro-l-arginine methyl ester and mitochondrial inhibitors (rotenone and 2-thenoyltrifluoroacetone) decreased oxidative stress levels in cardiomyocytes from HFD-fed WT mice. Mitochondrial respiration was altered in NOS3−/− mice but did not worsen after HFD and TAC. In contrast with its protective role in SD, NOS3 increases LV adverse remodeling after pressure overload in HFD-fed, insulin resistant mice. Interactions between NOS3 and mitochondria may be responsible for increased oxidative stress levels in HFD-fed WT mice hearts.

Download Full-text