Strenuous physical exercise accelerates the lipid peroxide clearing transport by HDL.

PURPOSE: Physical exercise has cardioprotective functions, which have been partly linked to high-density lipoprotein (HDL), and its functions. We studied the effects of endogenous oxidative stress, induced by acute exhaustive physical exercise, on concentration of oxidized HDL lipids. METHODS: Twenty-four male national top-level endurance runners, 12 middle-distance runners and 12 marathon runners performed a maximal run on a treadmill until exhaustion. We analyzed concentrations of oxidized HDL (oxHDLlipids) and LDL lipids (oxLDLlipids), serum antioxidant potential (TRAP), paraoxonase activity and malondialdehyde. Venous blood samples were taken before, immediately, 15 and 90 min after exercise. RESULTS: Immediately after the treadmill run the concentration of oxHDLlipids was increased by 24 % (p < 0.01). Simultaneously, the ratio of oxHDLlipids to oxLDLlipids increased by 55 % and the oxLDLlipids levels decreased by 19 % (p < 0.001), while serum malondialdehyde and TRAP increased by 54 % (p < 0.001) and 29 % (p < 0.01), respectively. After the 90 min recovery the concentration of oxHDLlipids was decreased towards the pre-exercise level, but that of oxLDLlipids remained decreased below pre-exercise values (p < 0.001). The change in oxLDLlipids after the run correlated positively with VO2max (r = 0.67, p < 0.001) and negatively with the change in paraoxonase activity (r = -0.47, p < 0.05). CONCLUSIONS: We conclude that acute exhaustive physical exercise increased the concentration of oxHDLlipids and decreased that of oxLDLlipids and the ratio of oxLDLlipids to oxHDLlipids, which suggests that during physical exercise HDL has an active role in the removal of lipid peroxides.

Co-existence of insulin resistance and high concentrations of circulating oxidized LDL lipids.

INTRODUCTION: Insulin metabolism has been previously linked to oxidized low-density lipoproteins (ox-LDL), but corroborating intervention studies are lacking. We investigated whether changes in ox-LDL levels are accompanied by changes in insulin sensitivity in a 32-month life-style intervention study. MATERIALS AND METHODS: A 2-month weight reduction was followed by 6-month diet and exercise counselling and a 2-year follow-up period. Men of 35-50 years of age, BMI ≥ 30 kg/m(2), and waist circumference > 100 cm were recruited via newspapers in the city of Tampere, Finland. Of the 90 men meeting the inclusion criteria, 67 (76%) completed the study. Ox-LDL was estimated as the presence of oxidized lipids in LDL. Homeostasis model assessment of insulin resistance (HOMA-IR), ox-LDL, and ratio of ox-LDL and high-density lipoprotein cholesterol (ox-LDL/HDL-c) were used as the main outcome measures. RESULTS: The detected changes in HOMA-IR were strikingly similar to those in ox-LDL and ox-LDL/HDL-c. Compared to the first HOMA-IR quartile, the fourth quartile had 23%-51% higher concentrations in ox-LDL and ox-LDL/HDL-c at all time points (P < 0.05 for all). CONCLUSION: This weight reduction intervention study adds evidence to support the connection between insulin metabolism and oxidized LDL, possibly contributing to the higher incidence of atherosclerotic cardiovascular diseases among diabetic patients.

Smoking and low serum testosterone associates with high concentration of oxidized LDL.

BACKGROUND: The interplay between smoking, oxidized low-density lipoprotein cholesterol (ox-LDL) and gonadal hormones has been scarcely investigated. AIM: To investigate associations in ox-LDL and gonadal hormones in smokers and non-smokers METHODS: Participants (n=164) were obtained from a population cohort of Finnish men aged 40-70 years. The subjects answered a detailed questionnaire on their health behaviour, medication, diseases, and different symptoms, and the hormonal and lipid profiles were measured. RESULTS: Smokers (n=33) had higher levels of ox-LDL (21%) and more free testosterone (12%) (P<0.01 for all) than non-smokers (n=131). The difference between smokers and non-smokers in ox-LDL persisted after controlling for possible confounding factors. When the smokers were divided into two subgroups (n=16 and n=17) according to total testosterone (< or =15 and >15 nmol/L), the ox-LDL in the low-testosterone subgroup was significantly higher (30%) than in the high-testosterone group (P=0.006). Similarly in the corresponding non-smoking subgroups (n=72 and n=59), ox-LDL was significantly higher (11%) in the low-testosterone subgroup than in the high-testosterone subgroup (P=0.012). CONCLUSIONS: Smoking men have significantly more ox-LDL than non-smoking men. Furthermore, if smoking is combined with a low serum testosterone, ox-LDL is even higher. This may suggest a higher risk for atherosclerosis.

The effect of probiotics on respiratory infections and gastrointestinal symptoms during training in marathon runners.

Heavy exercise is associated with an increased risk of upper respiratory tract infections. Strenuous exercise also causes gastrointestinal (GI) symptoms. In previous studies probiotics have reduced respiratory tract infections and GI symptoms in general populations including children, adults, and the elderly. These questions have not been studied in athletes before. The purpose of this study was to investigate the effect of probiotics on the number of healthy days, respiratory infections, and GI-symptom episodes in marathon runners in the summer. Marathon runners (N = 141) were recruited for a randomized, double-blind intervention study during which they received Lactobacillus rhamnosus GG (LGG) or placebo for a 3-mo training period. At the end of the training period the subjects took part in a marathon race, after which they were followed up for 2 wk. The mean number of healthy days was 79.0 in the LGG group and 73.4 in the placebo group (P = 0.82). There were no differences in the number of respiratory infections or GI-symptom episodes. The duration of GI-symptom episodes in the LGG group was 2.9 vs. 4.3 d in the placebo group during the training period (P = 0.35) and 1.0 vs. 2.3 d, respectively, during the 2 wk after the marathon (P = 0.046). LGG had no effect on the incidence of respiratory infections or GI-symptom episodes in marathon runners, but it seemed to shorten the duration of GI-symptom episodes.

Estrogen replacement therapy in combination with continuous intrauterine progestin administration reduces the amount of circulating oxidized LDL in postmenopausal women: dependence on the dose of progestin.

BACKGROUND: Oxidized low density lipoprotein (LDL) plays a key role in processes leading to atherosclerosis. Recent studies show that LDL oxidation in vitro is effectively prevented by estrogen. Yet, the effect of hormonal therapy (HT) on in vivo LDL oxidation has remained open. AIM: We used a novel methodology for the measurement of oxidized LDL in vivo in order to investigate the effects of HT. METHODS: The subjects were derived from two separate trials. In trial 1 (24 months) women (n = 32) used intra-uterine system releasing 10 micrograms/day levonorgestrel, and 2 mg oral estradiol. Trial 2 (12 months) consisted of two groups of subjects. One group (n = 30) used an intrauterine system releasing 20 micrograms/day levonorgestrel, and 2 mg estradiol; the other group (n = 32) received orally a combination of 1 mg norethisterone acetate and 2 mg estradiol. Blood samples were taken at 6 months intervals. Estimation of in vivo LDL oxidation was based on determination of baseline diene conjugation in isolated LDL. RESULTS: Hormonal therapy in trial 1 decreased markedly in vivo LDL oxidation. The effect was seen after 6 months' HT and became more pronounced towards the end of study (41% decrease; P < 0.0001). Contrary to this, in trial 2 the two different kinds of hormonal therapy schemes did not affect in vivo LDL oxidation. CONCLUSIONS: The strong effect seen in trial 1 shows that intrauterine levonorgestrel with 2 mg estradiol can lower LDL oxidation in vivo. The results show that this effect depends on dosage of the progestin.