Mendelian randomization supports causality between maternal hyperglycemia and epigenetic regulation of leptin gene in newborns

Leptin is an adipokine that acts in the central nervous system and regulates energy balance. Animal models and human observational studies have suggested that leptin surge in the perinatal period has a critical role in programming long-term risk of obesity. In utero exposure to maternal hyperglycemia has been associated with increased risk of obesity later in life. Epigenetic mechanisms are suspected to be involved in fetal programming of long term metabolic diseases. We investigated whether DNA methylation levels near LEP locus mediate the relation between maternal glycemia and neonatal leptin levels using the 2-step epigenetic Mendelian randomization approach. We used data and samples from up to 485 mother-child dyads from Gen3G, a large prospective population-based cohort. First, we built a genetic risk score to capture maternal glycemia based on 10 known glycemic genetic variants (GRS10) and showed it was an adequate instrumental variable (β = 0.046 mmol/L of maternal fasting glucose per additional risk allele; SE = 0.007; P = 7.8 × 10(-11); N = 467). A higher GRS10 was associated with lower methylation levels at cg12083122 located near LEP (β = -0.072 unit per additional risk allele; SE = 0.04; P = 0.05; N = 166). Direction and effect size of association between the instrumental variable GRS10 and methylation at cg12083122 were consistent with the negative association we observed using measured maternal glycemia. Lower DNA methylation levels at cg12083122 were associated with higher cord blood leptin levels (β = -0.17 log of cord blood leptin per unit; SE = 0.07; P = 0.01; N = 170). Our study supports that maternal glycemia is part of causal pathways influencing offspring leptin epigenetic regulation.

Weight gain since menopause and its associations with weight loss maintenance in obese postmenopausal women

Objective

To examine the association between weight gain since menopause and weight regain after a weight loss program.

Methods

Participants were 19 obese women who participated in a 15-week weight loss program and a 12-month follow-up. Main outcomes were: body composition, resting metabolic rate, energy intake, energy expenditure, and weight regain at follow-up.

Results

All body composition measures significantly decreased after intervention (all P ≤ 0.01) while all measures of fatness increased significantly after the 12-month follow-up (P ≤ 0.01). Body weight gain since menopause was associated with body weight regain (r = 0.65; P = 0.003) after follow-up even after adjustment for confounders.

Conclusion

Weight gain since menopause is associated with body weight regain following the weight loss program. Therefore, weight gain since menopause should be considered as a factor influencing weight loss maintenance in older women.

Quality of life in type 2 diabetes patients under intensive multitherapy

AIM

To assess the impact of an intensive multitherapy (IMT) on perceived quality of life (QOL), attitudes, knowledge and diabetes self-management in patients with poorly controlled type 2 diabetes.

METHODS

A 12-month randomized trial was conducted in 72 patients with type 2 diabetes, HbA1c>or=8%, blood pressure (BP)>130/80 mmHg and dyslipidemia. Subjects were assigned to the IMT or control group, each n=36. IMT consisted in monthly visits including clinical and biochemical assessment, education sessions on diet, physical exercise, medical management of diabetes and associated diseases and adjustments in medication. Control patients were under the care of their physicians. We developed and validated a diabetes-specific questionnaire assessing QOL, attitudes, knowledge, diabetes self-management and socio-demographic data for this study. Outcomes were measured at 0, 6 and 12 months.

RESULTS

Subjects were 54.8+/-8.1 years old (duration of diabetes: 10.3+/-7.2 years). At baseline, questionnaires showed no difference in QOL between groups. At 12 months, QOL improved significantly in the IMT group when compared to controls (+13.2+/-10.3/+5.6+/-13.2%, P=0.003), particularly with respect to the satisfaction scale (+25.3+/-13.9/+5.4+/-21.7%, P<0.001). QOL was not affected by complications or hypoglycaemic episodes. QOL scores improved in IMT subjects who began insulin therapy during the trial. Attitude scores, in the high normal range at baseline, did not change. Knowledge (+18.2+/-26.3/+8.9+/-30.4%, P=0.047) and diabetes self-management (+22.6+/-35.3/+6.8+/-20.1%, P<0.001) improved.

CONCLUSIONS

In poorly controlled subjects, QOL improved statistically despite the inherent constraints imposed by IMT.

Effects of aerobic physical exercise in the elderly with type 2 diabetes mellitus

The objective of this study was to determine the impact of an aerobic physical exercise program in the treatment of a group of elderly patients with type 2 diabetes mellitus (DM) in relation to metabolic control, physical capacity, quality of life (QOL) and attitudes toward diabetes. Patients were randomly assigned to either an experimental (n=19) or a control (n=20) group. The following measurements were conducted at baseline and after week 16: glycosylated hemoglobin (hbA1c), fructosamine, 3 h oral glucose tolerance test, treadmill test (Balke-Naughton), and a questionnaire on QOL and attitudes toward DM. After the intervention, the experimental group showed a significant decrease of glucose excursion during the oral glucose tolerance test (OGTT) (area under the curve) (16.6+/-3.8 vs. 15.3+/-3.1, P<0.05) and an increase in total time on the treadmill (s) (423+/-207 vs. 471+/-230, P<0.05). An improvement in the attitudes toward DM was observed in the experimental group (P=0.01) but not in the control group. Female gender, higher body mass index and hbA1c were factors associated with a response to the intervention. This study suggests that physical exercise has significant effects on glucose excursion during an OGTT and exercise tolerance in elderly patients with type 2 DM.

Evaluation of postural stability in elderly with diabetic neuropathy

OBJECTIVE

The objective of this study was to compare clinical and biomechanical characteristics of balance in diabetic polyneuropathic elderly patients and normal age-matched subjects.

RESEARCH DESIGN AND METHODS

Fifteen elderly with distal neuropathy (DNP) and 15 healthy age-matched subjects were evaluated with the biomechanical variable COP-COM, which represents the distance between the center of pressure (COP) and the center of mass (COM). Measurements were taken in the quiet position with a double-leg stance, in eyes-open (EO) and eyes-closed (EC) conditions. Subjects were also assessed with clinical balance evaluations.

RESULTS

The COP-COM variable was statistically significantly larger in the DNP group than in the healthy group in anterior-posterior (A/P) and medial-lateral (M/L) directions. Furthermore, the DNP group showed statistically significantly larger amplitudes of the COP-COM variable without vision. The severity of the neuropathy, as quantified using the Valk scoring system, was correlated with COP-COM amplitude in both directions.

CONCLUSIONS

Evaluation of the postural stability of an elderly diabetic population using the COP-COM variable can detect a very small change in postural stability and could be helpful in identifying elderly with DNP at risk of falling.

The degree of hyperinsulinemia and impaired glucose tolerance predicts plasma leptin concentrations in women only: a new exploratory paradigm

Plasma leptin has been shown to correlate positively with many indices of obesity, as well as insulin resistance. For a given body weight, the levels are higher in women than in men, but the reasons for this difference are not clear. Insulin has been shown to stimulate leptin production by adipose tissue in vivo and in vitro. Previous studies have reported that leptin levels are similar in diabetic and nondiabetic individuals. However, these studies were not performed in newly diagnosed diabetics, and other variables (such as gender) could have confounded the results. Therefore, the goal of the present cross-sectional study is to examine the effect of metabolic variables (such as glucose and insulin) on plasma leptin concentrations in men and women separately. We measured leptin levels in 48 subjects (17 with newly diagnosed type 2 diabetes mellitus, 13 with impaired glucose tolerance [IGT], and 18 normal individuals). The 3 groups were well matched for gender, age, and body mass index (BMI). When adjusted for the BMI and gender, a statistically significant gender-related difference in mean plasma leptin was observed across the 3 glucose tolerance subgroups (P < .03 by analysis of covariance [ANCOVA]). More specifically, plasma leptin levels were, on average, 44% lower in women with diabetes or IGT versus normal women (P < .02). No such between-group difference was observed in the men. In univariate analysis in the same female subgroup, plasma leptin correlated positively with fasting insulin (rs = +.43, P < .06) and negatively with 2-hour post-75-g glucose load plasma glucose concentration (rs = -.54, P < .02). In a multiple regression model controlling for the BMI in the female subgroup, circulating insulin and glucose concentrations 2 hours after the 75-g glucose load were good predictors of fasting plasma leptin (r = +.38, P = .02 and r = -.70, P < .001, respectively). Leptin levels in women appear to be influenced independently and to an important degree by ambient plasma glucose and plasma insulin concentrations. These findings suggest that the synthesis of leptin by adipose tissue is more susceptible to in vivo regulation by insulin and glucose in women than in men. Plasma leptin concentrations were also lower in women with IGT or type 2 diabetes versus normal women, suggesting that fasting and/or postprandial hyperglycemia interferes with the stimulatory effect of plasma insulin on the synthesis of leptin by adipose tissue in women only.

[Abnormal response of growth hormone to oral glucose tolerance test in obesity]

In obesity, it is well known that basal growth hormone (GH) levels can be suppressed and they may show an impaired response to various stimuli like hypoglycemia, stress, and GHRH. However, the inhibitory effect of hyperglycemia on GH in this condition has not been well studied. We analyzed the GH response to an oral glucose tolerance test (OGTT) in 25 unselected patients with morbid obesity who were not diabetic, glucose intolerant or affected by renal or hepatic disease. Ten (40%) of the 25 subjects had an abnormal response of GH to the OGTT, expressed by a lack of suppression of GH levels below 2 micrograms/L within 60 minutes of glucose administration. Three subjects even had a paradoxal increase of GH levels of more than 50% of the basal level. There was no significant difference between these subjects regarding their age, BMI and, serum levels of glucose, insulin, C peptide, or insulin/glucose ratio. After weight loss, three of four patients normalized their GH response. Thus, we conclude that patients with morbid obesity frequently have an abnormal response of GH to OGTT (40% vs 4-8% in normal subjects). This finding must be taken into consideration when interpreting GH levels in these patients. A normalization of this response can be expected after weight loss.

Blockade of insulin sensitive steady-state R-type Ca2+ channel by PN 200-110 in heart and vascular smooth muscle

The effect of high K+ concentration, insulin and the L-type Ca2+ channel blocker PN 200-110 on cytosolic intracellular free calcium ([Ca2+]i) was studied in single ventricular myocytes of 10-day-old embryonic chick heart, 20-week-old human fetus and rabbit aorta (VSM) single cells using the Ca(2+)-sensitive fluorescent dye, Fura-2 microfluorometry and digital imaging technique. Depolarization of the cell membrane of both heart and VSM cells with continuous superfusion of 30 mM [K+]o induced a rapid transient increase of [Ca2+]i that was followed by a sustained component. The early transient increase of [Ca2+]i by high [K+]o was blocked by the L-type calcium channel antagonist nifedipine. However, the sustained component was found to be insensitive to this drug. PN 200-110 another L-type Ca2+ blocker was found to decrease both the early transient and the sustained increase of [Ca2+]i induced by depolarization of the cell membrane with high [K+]o. Insulin at a concentration of 40 to 80 microU/ml only produced a sustained increase of [Ca2+]i that was blocked by PN 200-110 or by lowering the extracellular Ca2+ concentration with EGTA. The sustained increase of [Ca2+]i induced by high [K+]o or insulin was insensitive to metabolic inhibitors such as KCN and ouabain as well to the fast Na+ channel blocker, tetrodotoxin and to the increase of intracellular concentrations of cyclic nucleotides. Using the patch clamp technique, insulin did not affect the L-type Ca2+ current and the delayed outward K+ current. These results suggest that the early increase of [Ca2+]i during depolarization of the cell membrane of heart and VSM cells with high [K+]o is due to the opening and decay of an L-type Ca2+ channel. However, the sustained increase of [Ca2+]i during a sustained depolarization is due to the activation of a resting (R) Ca2+ channel that is insensitive to lowering [ATP]i and sensitive to insulin.

[Comparison of the efficacy of cefotaxime alone and the combination cefazolin-tobramycin in the treatment of enterobacterial septicemia]

In a prospective, randomized study we compared cefotaxime (C) with tobramycin plus cefazolin (C + T) in the treatment of Enterobacterial septicemia. Twenty-five patients received C and twenty two C + T. There are 8 treatment failures, in C + T group, 3 in C group. We observed 5 adverse effects, 2 in the C group (1 reversible collapse and 1 Pseudomonas aeruginosa superinfection) and 3 in the C + T group (acute renal failures). We conclude that C may be more effective and less toxic than cefazolin plus tobramycin for patients with Enterobacterial septicemia.

[Longitudinal study of the changes in glycosylated hemoglobin in normal pregnancy]

A longitudinal study of HbA1c levels during normal pregnancy was carried out on 54 women. Three measurements were systematically performed around the 14th, the 24th and the 33rd weeks of gestation. On average, an initial decrease was observed in the first period, followed by a significant increase in the second period. The latter increase was negatively related to age (r = -0.33; p less than 0.05) and to prepregnancy weight (r = -0.26; p = 0.06), but neither to the birth weight of the offspring nor to total weight gain. The variation of HbA1c in the first period was not related to any of these four factors.