Time to Consider the "Exposome Hypothesis" in the Development of the Obesity Pandemic

The obesity epidemic shows no signs of abatement. Genetics and overnutrition together with a dramatic decline in physical activity are the alleged main causes for this pandemic. While they undoubtedly represent the main contributors to the obesity problem, they are not able to fully explain all cases and current trends. In this context, a body of knowledge related to exposure to as yet underappreciated obesogenic factors, which can be referred to as the "exposome", merits detailed analysis. Contrarily to the genome, the "exposome" is subject to a great dynamism and variability, which unfolds throughout the individual's lifetime. The development of precise ways of capturing the full exposure spectrum of a person is extraordinarily demanding. Data derived from epidemiological studies linking excess weight with elevated ambient temperatures, in utero, and intergenerational effects as well as epigenetics, microorganisms, microbiota, sleep curtailment, and endocrine disruptors, among others, suggests the possibility that they may work alone or synergistically as several alternative putative contributors to this global epidemic. This narrative review reports the available evidence on as yet underappreciated drivers of the obesity epidemic. Broadly based interventions are needed to better identify these drivers at the same time as stimulating reflection on the potential relevance of the "exposome" in the development and perpetuation of the obesity epidemic.

Changes in copper and zinc plasma concentrations during the normal menstrual cycle in women

OBJECTIVE

To investigate whether there is a fluctuation of the copper and zinc plasma levels during the menstrual cycle and if this correlates to the physiological fluctuations of estradiol and progesterone plasma concentrations in eumenorrhoic women.

METHODS

We studied 14 eumenorrhoic women. Copper (Cu), zinc (Zn), estradiol (E2) and progesterone (Prg) plasma concentrations, during time of menstruation (time 1), midfollicular phase (time 2), time of ovulation (time 3) and midluteal phase (time 4) were determined.

RESULTS

We observed significant changes in both copper plasma concentrations and zinc plasma concentrations during the four times studied (p < 0.05). The changes of Cu during the various phases correlated negatively with the changes in E2 (r > 0.5, p < 0.05), whereas the changes of Zn correlated positively with those of E2 (r > 0.8, p < 0.05). We were unable to demonstrate any statistically significant correlation between Cu and Prg or Zn and Prg.

CONCLUSIONS

This study indicates that there is a cyclic fluctuation of Cu and Zn concentrations in plasma during the menstrual cycle, in healthy eumenorrhoic women. This cyclic fluctuation might be due to the cyclic fluctuation of plasma levels of E2.

Serum adiponectin and leptin levels and insulin resistance in children born large for gestational age are affected by the degree of overweight

OBJECTIVE

Children born large for gestational age (LGA) are prone to develop insulin resistance later in life. One factor that affects insulin sensitivity is the hormone adiponectin. The aim of this study was to determine whether being LGA has an impact on serum adiponectin and leptin levels and insulin resistance parameters during childhood, taking into account the severity of overweight.

STUDY DESIGN

Serum levels of adiponectin, leptin, fasting glucose and insulin, homeostasis model assessment insulin resistance index (HOMA-IR), and anthropometric indices were evaluated in groups of non-obese children aged 6.5-8 years, born appropriate for gestational age (AGA, n = 40) or LGA (n = 41), matched for age, gender, height, weight and body mass index. The LGA group was divided in two subgroups according to the degree of overweight: (a) LGA with birthweight 90th-97th percentile (n = 25); and (b) LGA with birthweight > 97th percentile (n = 16).

RESULTS

LGA children had a higher mean serum adiponectin level than AGA children: 17.0 +/- 9 vs. 11.1 +/- 5 (microg/ml) (P < 0.01). LGA children had also higher insulin 6.2 +/- 2.8 vs. 4.8 +/- 2.4 (microU/ml) (P < 0.05) and HOMA-IR 1.32 +/- 0.66 vs. 1.02 +/- 0.55 (P < 0.01) than AGA children. Children born LGA > 97th percentile had a significantly higher mean serum leptin level than both AGA and LGA 90th-97th percentile children (17 +/- 13, 9.6 +/- 9.5, 7.8 +/- 7.9 ng/ml, respectively, P < 0.05), and more severely affected insulin resistance indices than LGA 90th-97th percentile children. In the regression analysis, birthweight was found to be an independent predictor of adiponectin serum levels.

CONCLUSION

Prepubertal LGA-born children had a higher mean serum adiponectin levels than matched AGA controls despite the fact that they were more insulin resistant. The degree of excess in utero weight gain appears to influence the metabolic profile in LGA-born prepubertal children. Further studies are needed to delineate the role of adiponectin in the risk of development of insulin resistance in children born LGA.

Withdrawal syndrome following cessation of antihypertensive drug therapy

In this study, a review of the available information concerning abrupt withdrawal of antihypertensive drug therapy is presented. Abrupt withdrawal of these drugs can produce a syndrome of sympathetic overactivity that includes nervousness, tachycardia, headache, agitation and nausea 36-72 h after cessation of the drug. A withdrawal syndrome may occur after discontinuation of almost all types of antihypertensive drugs, but mostly occurs with clonidine, beta-blockers, methyldopa and guanabenz. Less commonly can produce a rapid increase of the blood pressure to pre-treatment levels or above, or both and/or myocardial ischaemia. Although the exact incidence of the syndrome is not known, it appears to be rare, at least in patients receiving standard doses of the above antihypertensive drugs. The best treatment is prevention. In this study regarding the withdrawal syndrome that follows cessation of antihypertensive drugs therapy, a reference to the abrupt discontinuation of the main categories of antihypertensive drugs is also attempted.

Effects of cigarette smoking on the antioxidant defence in young healthy male volunteers

Cigarette smoking induces a significant oxidant effect related to variety of free radical-related diseases often affecting the upper respiratory tract, unless it is effectively compensated by the antioxidant barriers of the humans. In the present study, the evaluation of the antioxidant compensatory mechanisms, by estimating the antioxidant capacity of extracellular defence (saliva and plasma) and the intracellular resistance of peripheral lymphocytes to oxidative stress in young healthy smokers, was investigated. Twenty young healthy male smokers and 20 age-matched non-smokers with similar dietary profiles were enrolled in the study. Total saliva and plasma samples were collected from both groups, and total antioxidant capacity (TAC) and lag time were estimated. The latter was also repeated in smokers just after a cigarette smoking. Peripheral lymphocytes isolated from the subjects of both groups were also tested for their inherent DNA damage as well as for their ability to resist H2O2-induced DNA damage by using the comet assay. TAC of plasma was found significantly higher in smokers compared to non-smokers (p <0.004), whereas no difference was recorded in plasma lag time values. Lymphocytes of smokers manifested a significantly decreased oxidant resistance (increased DNA fragmentation) to H2O2, in comparison to non-smokers. Our results indicate that young smokers do not manifest different salivary antioxidant defence than non-smokers. They exhibit, however, a higher plasma antioxidant capacity, but a significantly reduced ability of blood lymphocytes, to resist to H2O2-induced DNA damage.

The height of the pituitary in preterm infants during the first 2�years of life: an MRI study

Pituitary secretory activity is different in premature and full-term infants. The height of the pituitary is a marker of its secretory activity. Our purpose was to use MRI to measure height of the pituitary of premature infants and to compare it with full-term controls. The height was measured on a midline sagittal T1-weighted image in 86 premature infants (gestational age 26-36.9 weeks, mean 32.3+/-2.85 weeks, corrected age 0.33-2 years, mean 0.76+/-0.42 years) and in 70 age- and sex-matched full-term controls. The children were was divided into four age groups: A: > or =0.5 years; B: 0.51-1.0 year; C: 1.01-1.5 years; and D: 1.51-2.00 years. The gland was significantly (P<0.01) higher in the preterm infants than in the controls (3.88+/-0.61 vs 3.31+/-0.64 mm). In the preterm group no significant difference was found between children small or appropriate for gestational age or between those with and without periventricular leukomalacia. Pituitary height by age group was: A: 3.71+/-0.57, B: 3.81+/-0.56, C: 4.09+/-0.68; and D:4.45+/-0.57 mm; statistically significant (P<0.01) differences were found between groups A and D and B and D. The pituitary is thus higher in premature than in full-term controls and shows a trend to increase after the first year of corrected-age life.

Investigating the Role of Functional Polymorphism of Maternal and Neonatal Vitamin D Binding Protein in the Context of 25-Hydroxyvitamin D Cutoffs as Determinants of Maternal-Neonatal Vitamin D Status Profiles in a Sunny Mediterranean Region

Recent results indicate that dysregulation of vitamin D-binding protein (VDBP) could be involved in the development of hypovitaminosis D, and it comprises a risk factor for adverse fetal, maternal and neonatal outcomes. Until recently, there was a paucity of results regarding the effect of maternal and neonatal VDBP polymorphisms on vitamin D status during pregnancy in the Mediterranean region, with a high prevalence of hypovitaminosis D. We aimed to evaluate the combined effect of maternal and neonatal VDBP polymorphisms and different maternal and neonatal 25-hydroxyvitamin D (25(OH)D) cut-offs on maternal and neonatal vitamin D profile. Blood samples were obtained from a cohort of 66 mother–child pairs at birth. Our results revealed that: (i) Maternal VDBP polymorphisms do not affect neonatal vitamin D status at birth, in any given internationally adopted maternal or neonatal cut-off for 25(OH)D concentrations; (ii) neonatal VDBP polymorphisms are not implicated in the regulation of neonatal vitamin D status at birth; (iii) comparing the distributions of maternal VDBP polymorphisms and maternal 25(OH)D concentrations, with cut-offs at birth, revealed that mothers with a CC genotype for rs2298850 and a CC genotype for rs4588 tended to demonstrate higher 25(OH)D (≥75 nmol/L) during delivery (p = 0.05 and p = 0.04, respectively), after adjustments for biofactors that affect vitamin D equilibrium, including UVB, BMI and weeks of gestation. In conclusion, this study from Southern Europe indicates that maternal and neonatal VDBP polymorphisms do not affect neonatal vitamin D status at birth, whereas mothers with CC genotype for rs2298850 and CC genotype for rs4588 demonstrate higher 25(OH)D concentrations. Future larger studies are required to establish a causative effect of these specific polymorphisms in the attainment of an adequate (≥75 nmol/L) maternal vitamin D status during pregnancy.

Consequences of the discontinuation of antihypertensive treatment in successfully treated patients

Hypertension is probably the most important public health problem in developed countries. Over the last 40 years, an increasing number of hypertensive patients have been treated with various antihypertensive drugs. If the blood pressure (BP) is controlled, the discontinuation of the antihypertensive drug may result either in a relapse of the disease or in the maintenance of normal BP for a long time. In this study, we discuss the available data regarding the consequences of antihypertensive drug withdrawal in successfully treated patients and we suggest guidelines for the application in clinical practice.

The Associations of Dietary Vitamin K Intake and Circulating Vitamin 25(OH)D with Serum Lipoprotein Levels: The Vitamin Deficiency Matters

A synergistic interplay between vitamins K and D appears to exist. We aimed to investigate for the first time whether the associations of dietary vitamin K intake and circulating 25(OH)D with serum lipoprotein levels are influenced by the existence of deficiency of either or both vitamins K and D. Sixty individuals [24 males, 36(18-79) years old] were examined. Vitamin deficiency of K1 and D were defined as vitamin K1 intake/body weight (BW)<1.00 μg/kg/day and circulating 25(OH)D<20 ng/ml, respectively. In individuals with vitamin K1 deficiency, the vitamin K1 intake/BW correlated positively with high density lipoprotein-cholesterol (HDL-C) (r=0.509, p=0.008) and negatively with serum triglycerides (TG) (r=-0.638, p=0.001), whereas circulating 25(OH)D correlated negatively with TG (r=-0.609, p=0.001). In individuals with vitamin D deficiency, the vitamin K1 intake/BW correlated positively with HDL-C (r=0.533, p=0.001) and negatively with TG (r=-0.421, p=0.009), while circulating 25(OH)D correlated negatively with TG (r=-0.458, p=0.004). The above-mentioned associations of vitamin K1 intake/BW and circulating 25(OH)D with serum lipoproteins were not detected in individuals without vitamin K1 deficiency or the ones without vitamin D deficiency. The vitamin K2 intake/BW correlated negatively with low density lipoprotein-cholesterol (LDL-C) (r=-0.404, p=0.001). In conclusion, the associations of vitamin K1 intake with TG and HDL-C and of circulating 25(OH)D with TG were more pronounced in individuals with deficiency of either or both vitamins K1 and D. Increased dietary vitamin K2 intake was associated with decreased LDL-C.