Plasma levels of insulin-like growth factor-I, insulin-like growth factor binding protein-1, coenzyme Q10 and vitamin E in female populations from Poland, Serbia and Sweden

Transcriptional pathways of elevated fasting blood glucose associated with short-term exposure to ultrafine particles: A panel study in Beijing, China

There is growing concern about the strong health effects of ultrafine particles (UFPs). However, less is known about the biological mechanisms. The objective of this study is to examine the association between short-term exposure to UFPs and fasting blood glucose (FBG) levels, and explore the potential physiological mechanisms at transcriptional levels. In a panel study of 135 participants, we measured FBG and the whole blood transcriptome repeatedly. The concentrations of ambient air pollutants were monitored continuously at a station. Linear mixed-effects models coupled with a mediating effect model were used to discriminate transcripts associated with air pollutant exposure and ln-transformed FBG levels. We found that FBG was significantly associated with interquartile range increase in the average UFPs concentrations 1-13 d prior to the clinical visits (ranging from 5.1% [95% CI 2.0-8.1%] in the 1-d time-window to 12.1% [95% CI 6.5-17.8%] in the 13-d time-window). Top 1000 transcripts associated with FBG increase following UFPs exposure were enriched into some biological pathways, such as pro-opiomelanocortin processing, negative regulation of hypoxia-inducible factor 1 A function, ubiquinone metabolism, and antigen presentation by major histocompatibility complex class I, classical pathway. These results suggest that elevated FBG associated with UFPs exposure may be related to regulation of metabolism, immune response, DNA damage, and apoptosis and survival.

The insulin-like growth factor system: A target for endocrine disruptors?

The insulin-like growth factor (IGF) system is a critical regulator of growth, especially during fetal development, while also playing a central role in metabolic homeostasis. Endocrine disruptors (EDs) are ubiquitous compounds able to interfere with hormone action and impact human health. For example, exposure to EDs is associated with decreased birthweight and increased incidence of metabolic disorders. Therefore, the IGF system is a potential target for endocrine disruption. This review summarises the state of the science regarding effects of exposure to major classes of endocrine disruptors (dioxins and dioxin-like compounds, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, phthalates, perfluoroalkyl substances and bisphenol A) on the IGF system. Evidence from both experimental models (in vitro and in vivo) and epidemiological studies is presented. In addition, possible molecular mechanisms of action and effects on methylation are discussed. There is a large body of evidence supporting the link between dioxins and dioxin-like compounds and IGF disruption, but mixed findings have been reported in human studies. On the other hand, although only a few animal studies have investigated the effects of phthalates on the IGF system, their negative association with IGF levels and methylation status has been more consistently reported in humans. For polybrominated diphenyl ethers, perfluoroalkyl substances and bisphenol A the evidence is still limited. Despite a lack of studies for some ED classes linking ED exposure to changes in IGF levels, and the need for further research to improve reproducibility and determine the degree of risk posed by EDs to the IGF system, this is clearly an area of concern.

Potential of Gentiana lutea for the Treatment of Obesity-associated Diseases

BACKGROUND

Obesity, diabetes, and associated diseases are increasing all over the world, and pose a great burden on public health. According to the latest reports, 440 million people are suffering from diabetes. Diabetes is caused by impaired ability to produce or respond to the hormone insulin consequently resulting in hyperglycemia.

METHODS

Data used for this review was obtained by using PUBMED/MEDLINE (1987-2018). The main data search terms were: Gentiana lutea, Gentiana lutea extract, Gentiana lutea constituents, obesity, diabetes mellitus, diabetic complications.

RESULTS

In the present review, we describe the potential of root powder of yellow gentian (Gentiana lutea) for the prevention of obesity and diabetes including complications related to this disease.

CONCLUSION

Reasonably effective, low-cost alternatives could fulfill an important role for a large part of the human population and could be of great value for the food market. Even a modest reduction of morbidity and mortality with respect to this disease translates into millions of lives saved.

Coenzyme Q10 and oxidative stress, the association with peripheral sensory neuropathy and cardiovascular disease in type 2 diabetes mellitus

OBJECTIVE

Our study aimed to explore associations between metabolic control, oxidative stress and coenzyme Q10 (CoQ10) in relation to diabetes complications in a representative population of type 2 diabetes.

RESEARCH DESIGN AND METHODS

A geographic cohort of 156 subjects was recruited. Serum concentrations of CoQ10 and vitamin E were measured by HPLC. ROS was determined by free oxygen radicals testing (FORT). Glutaredoxin (Grx) activity, oxidized LDL cholesterol (oxLDLc), high sensitive CRP (hsCRP), HbA1c, urine albumin, serum creatinine, serum cystatin C, and plasma lipids were assayed with routine laboratory protocols.

RESULTS

Serum CoQ10 was higher than in nondiabetics. HbA1c, fP-glucose, hyperlipidemia, inflammation (hsCRP), and increased BMI were associated with signs of oxidative stress as increased levels of FORT, Grx activity and/or increased levels of oxLDLc Oxidative stress was found to be strongly correlated with prevalence of cardiovascular disease (CVD) and peripheral sensory neuropathy (PSN). In both gender groups there were positive correlations between CoQ10 and oxLDLc, and between BMI and the ratio CoQ10/chol. Grx activity was inversely correlated to oxLDLc and CoQ10. Women with CVD and PSN had higher waist index, oxLDLc, and FORT levels compared to men but lower CoQ10 levels. Men had worse kidney function and lower vitamin E. Multiple regression analysis showed increased levels of CoQ10 to be significantly correlated with increased levels of cholesterol, triglycerides, vitamin E, fB-glucose and BMI.

CONCLUSIONS

Hyperlipidemia, hyperglycemia and inflammation were associated with oxidative stress, which was correlated to the prevalence of diabetes complications. CoQ10 was increased in response to oxidative stress. There were gender differences in the risk factors associated with diabetes complications.

Determination of the coenzyme Q10 status in a large Caucasian study population

Coenzyme Q10 (CoQ10 ) exists in a reduced (ubiquinol) and an oxidized (ubiquinone) form in all human tissues and functions, amongst others, in the respiratory chain, redox-cycles, and gene expression. As the status of CoQ10 is an important risk factor for several diseases, here we determined the CoQ10 status (ubiquinol, ubiquinone) in a large Caucasian study population (n = 1,911). The study population covers a wide age range (age: 18-83 years, 43.4% men), has information available on more than 10 measured clinical phenotypes, more than 30 diseases (presence vs. absence), about 30 biomarkers, and comprehensive genetic information including whole-genome SNP typing (>891,000 SNPs). The major aim of this long-term resource in CoQ10 research is the comprehensive analysis of the CoQ10 status with respect to integrated health parameters (i.e., fat metabolism, inflammation), disease-related biomarkers (i.e., liver enzymes, marker for heart failure), common diseases (i.e., neuropathy, myocardial infarction), and genetic risk in humans. Based on disease status, biomarkers, and genetic variants, our cohort is also useful to perform Mendelian randomisation approaches. In conclusion, the present study population is a promising resource to gain deeper insight into CoQ10 status in human health and disease.

Glutaredoxin mediated redox effects of coenzyme Q10 treatment in type 1 and type 2 diabetes patients

The possible beneficial effects of coenzyme Q10 (CoQ10) supplementation on disease progression and oxidant status in diabetes remains debated. In the present study, patients with type 1 and type 2 diabetes were treated with oral CoQ10, 100 mg twice daily for 12 weeks. We assessed total antioxidant capacity, intra- and extracellular levels of the redox regulating protein glutaredoxin 1 (Grx1), CoQ10, oxidized LDL-cholesterol, lipid profile and HbA1c. We have previously shown that extracellular Grx1 is increased in patients with type 2 diabetes compared to healthy subjects. In the present study, CoQ10 treatment significantly decreased serum Grx1 activity as well as total antioxidant capacity independent of type of diabetes, indicating an improvement to a less oxidized extracellular environment. The effect on serum Grx1 activity was more prominent in patients not on statin treatment. Conversely, intracellular Grx1 activity as well as mRNA levels increased independent of statin treatment. There was a significant improvement in oxidized LDL-cholesterol and lipid profile, with a tendency to improved metabolic control (HbA1c). Additionally, we describe for the first time that CoQ10 is a direct substrate for glutathione, and that Grx1 catalyzes this reaction, thus presenting a novel mechanism for CoQ10 reduction which could explain our findings of an increased intracellular Grx1. In conclusion, 12 weeks CoQ10 treatment significantly improved the extracellular redox balance and lipid profile, indicating that prolonged treatment may have beneficial effects also on clinical outcome in diabetes.

Relationship between functional capacity and body mass index with plasma coenzyme Q10 and oxidative damage in community-dwelling elderly-people

The impact of aging and physical capacity on coenzyme Q10 (Q10) levels in human blood is unknown. Plasma Q10 is an important factor in cardiovascular diseases. To understand how physical activity in the elderly affects endogenous Q10 levels in blood plasma, we studied a cohort of healthy community-dwelling people. Volunteers were subjected to different tests of the Functional Fitness Test Battery including handgrip strength, six-minute walk, 30 s chair to stand, and time up and go tests. Anthropometric characteristics, plasma Q10 and lipid peroxidation (MDA) levels were determined. Population was divided according to gender and fitness. We found that people showing higher levels of functional capacity presented lower levels of cholesterol and lipid peroxidation accompanied by higher levels of Q10 in plasma. The ratio Q10/cholesterol and Q10/LDL increased in these people. No relationship was found when correlated to muscle strength or agility. On the other hand, obesity was related to lower Q10 and higher MDA levels in plasma affecting women more significantly. Our data demonstrate for the first time that physical activity at advanced age can increase the levels of Q10 and lower the levels of lipid peroxidation in plasma, probably reducing the progression of cardiovascular diseases.

Association between dietary folate intake and serum insulin-like growth factor-1 levels in healthy old women

OBJECTIVE

High serum levels of insulin-like growth factor-1 (IGF-1) seem to coincide with higher rates of some types of cancer and the risk of all-cause mortality in old people. Eating vegetables seems to reduce IGF-1 levels because they are rich in micronutrients such as vitamins. This study investigates the possible association between vitamin intake and IGF-1 levels in a representative group of healthy elderly women with Mediterranean dietary habits.

DESIGN

This cross-sectional study included 124 healthy women with a mean age of 71.3 ± 4.2 years and a mean body mass index (BMI) of 27.37 ± 3.48 kg/m(2) attending a mild fitness program twice a week at public gyms in Padova. The main parameters considered were IGF-1 (measured by chemiluminescence) and diet, assessed on the basis of a 3-day record and a questionnaire on the frequency with which they usually ate certain foods.

RESULTS

The mean IGF-1 level for the sample as a whole was 136.2 ± 38.9 μg/l, and was significantly lower in women with a higher folate intake (p = 0.04). On simple linear analysis, the vitamins found associated with serum IGF-1 levels were: folates (r: -0.25; p = 0.003); vitamin E (r: -0.21; p = 0.01); vitamin D (r: -0.17; p = 0.03); and riboflavin (r: -0.16; p=0.03). After removing the effect of calorie, protein, carbohydrate and fat intake, and other known potential confounders (age, BMI, alcohol intake), only folate intake correlated with IGF-1 levels (r = -0.17; p = 0.04).

CONCLUSION

A folate-rich diet could have the effect of lowering circulating IGF-1 levels in elderly women.

Effects of lifestyle on plasma levels of the IGF system and the antioxidants coenzyme Q10 and vitamin E in Kenyan rural and urban populations

OBJECTIVE

Overnight fasting blood plasma insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-1 (IGFBP-1), coenzyme Q10, (CoQ) vitamin E and plasma lipids were compared between a semi-nomadic Samburu population and relatively urbanized cohorts from Nairobi, Kenya.

RESEARCH DESIGN AND METHODS

143 middle aged subjects without known diabetes were included. IGF-I and IGFBP-1 were analyzed by RIA, and CoQ and vitamin E by HPLC. Plasma lipid levels were analyzed by standard laboratory methods routinely used in the clinics.

RESULTS

The age adjusted IGF-I serum levels were low in the Samburu male and female populations, ranging from 0 to -4 IGFSD-score (SDS), and a minor part of the investigated population reaching as low as -5 and -7 SDS. The Nairobi cohorts showed significantly higher values reaching from -2.5 to +1 SDS (P<0.0001). The nomadic Samburu population showed fasting IGFBP-1 values ranging from 30-100 μg/l, while that of the urbanized Nairobi cohorts was considerably lower (25-60 μg/l) (P<0.0001). CoQ concentrations of the Nairobi cohorts were 1.5-2.0 nmol/ml similar to the levels found in several European countries. The Samburu population on the other hand showed extremely high CoQ values ranging from 2 to 9 nmol/ml (P<0.0001). Vitamin E levels of the Nairobi group were low (5-20 nmol/ml), but the Samburu population had even lower levels ranging from 3 to 15 nmol/ml (P<0.0001). Plasma lipid levels such as cholesterol, triglycerides, LDL/HDL, ApoB/ApoA ratios as well as BMI and weight were significantly higher in the Nairobi population (P<0.0001).

CONCLUSIONS

Low IGF-I and high IGFBP-1 levels of the Samburu cohorts indicate malnutrition. High lipid levels of the Nairobi cohorts indicate that these groups have several risk factors for cardiovascular diseases and diabetes type2.

Body composition and endocrine profile of male Olympic athletes striving for leanness

OBJECTIVE

To investigate the endocrine profile, body composition, and state of mood in male Olympic athletes participating in sports that do or do not emphasize leanness.

DESIGN

Cross-sectional study.

SETTING

Research unit at a university hospital.

PARTICIPANTS

Forty-four Swedish male Olympic athletes participating in 26 different sport disciplines.

MAIN OUTCOME MEASURES

Body composition was determined by dual-energy x-ray absorptiometry, and blood levels of steroid hormones and biomarkers of nutritional status were analyzed. In addition, states of mood were assessed employing the profile of mood states (POMS) test. The athletes were divided into 2 groups on the basis of whether their sporting discipline emphasized leanness or not.

RESULTS

In all subjects, body composition, hormone levels, and POMS scores were within normal ranges. However, the leanness athletes (n = 18) displayed significantly lower proportion of body fat (P < 0.01), higher spinal bone mineral density (P < 0.05), lower serum levels of free testosterone and leptin (P < 0.05), and higher serum levels of insulin-like growth factor binding protein 1 (P < 0.05) than nonleanness athletes (n = 26). Leanness athletes also had higher POMS scores for depression and anger, and a higher global POMS score (P < 0.05), the latter being positively correlated to the frequency of illness (r = 0.42, P < 0.01) before the Olympic Games.

CONCLUSION

Although there were no indications of energy deficiency or endocrine disturbance in the leanness athletes, their higher POMS scores and frequency of illness may indicate the potential harmfulness of their pursuit of outstanding athletic performance.

The relationship between dioxin-like polychlorobiphenyls and IGF-I serum levels in healthy adults: evidence from a cross-sectional study

OBJECTIVE

Insulin-like growth factor I (IGF-I) and dioxin-like polychlorobiphenyls (DL-PCBs) have been associated with the pathogenesis of several diseases like cancer, diabetes and growth disorders. Because it has been suggested that organohalogenated contaminants could influence IGF-I levels in adults, the potential relationship between DL-PCBs and IGF-I serum levels was studied in 456 healthy adults from a representative sample of the general population of the Canary Islands (Spain).

DESIGN

Free circulating serum levels of IGF-I and IGFBP-3 were measured through an ELISA methodology, while the serum levels of the 12 DL-PCBs congeners (IUPAC numbers # 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, and 189) were measured by gas chromatography/mass spectrometry (GC-MS).

RESULTS

DL-PCBs 156 and 167, Total DL-PCBs body burden (∑PCBs: sum over the 12 measured DL-PCBs), and Total toxic burden (in terms of toxic equivalence to dioxins: ∑TEQs) showed a trend of inverse association with IGF-I serum levels in the whole studied population. After adjusting for potential confounders, including gender, body mass index (BMI), age, and IGF-binding protein-3 (IGFBP-3), younger (18-45 years) women with lower BMI (<27 kg/m(2)) and detectable levels of DL-PCB-156 showed significantly lower IGF-I levels than those in the same age and BMI subgroup with non-detectable levels of DL-PCB-156 (p<0.001). Similarly, ∑PCBs and ∑TEQs showed a tendency to an inverse association with IGF-I levels in the same group of women (p=0.017 and p=0.019 respectively).

CONCLUSIONS

These findings suggest that DL-PCBs could be involved in the regulation of the IGF-system in a way possibly influenced by gender, age and BMI. Although these results should be interpreted with caution, such circumstances could contribute to explain the development of diseases associated to the IGF system.