Leptin, blood pressure, and aerobic capacity in women

The hyperleptinemia state can downregulate cardiorespiratory fitness and energy expenditure in obese women

INTRODUCTION

In general, in obese people a state of hyperleptinemia may impair both energy balance and the inflammatory process. However, it has not been fully investigated whether there is a relationship between hyperleptinemia and cardiorespiratory fitness (CRF) and resting energy expenditure (REE), in obese women.

METHODS

83 obese women were enrolled in this cross-sectional study. Anthropometric measures, body composition, REE, CRF and serum concentration of leptin were measured. Pearson's correlation coefficient was performed to examine the relationship between circulating leptin level and other clinical variables. Multiple regression analysis was applied to determine predictors of REE and CRF. Effects were considered significant at p≤0.05.

RESULTS

The most important finding in the present study is that the hyperleptinemia state was inversely correlated with CRF (r=-0.382, p=0.001) and REE (r=-0.447, p<0.001). Moreover, a positive correlation with fat mass was confirmed (r=0.419, p<0.001). In addition, hyperleptinemia was an independent negative predictor of REE (r²=-2.649, p=0.010) and CRF (r²=-2.335, p=0.023).

CONCLUSION

Together our results may suggest a vicious cycle between the state of hyperleptinemia and a decrease in energy expenditure and cardiorespiratory fitness in obese women, which can impair whole body energy homeostasis. This information is important to contribute to clinical practices.

Soluble Leptin Receptor and Risk of Gestational Diabetes in a Multiethnic Population: A Prospective Cohort Study

CONTEXT

Soluble leptin receptor (sOb-R), a potential marker of leptin resistance, is inversely associated with risk of type 2 diabetes, independently of leptin concentrations. We have previously shown that ethnic difference in leptin concentration may partly explain the increased risk of gestational diabetes (GDM) in South Asians.

OBJECTIVE

Our objective was to investigate whether sOb-R concentrations are associated with risk of GDM, whether concentrations of sOb-R differ across ethnic groups, and whether ethnic differences in sOb-R explain the ethnic differences in GDM risk.

DESIGN AND SETTING

The STORK Groruddalen study; a prospective cohort study of pregnant women living in Oslo, Norway, between May 2008 and May 2010.

PARTICIPANTS

Of the total sample (n = 823), 680 (47.1% Europeans) had sOb-R measured in pregnancy week 15 and an oral glucose tolerance test performed in week 28.

MAIN OUTCOME MEASURE

GDM was diagnosed according to World Health Organization 2013 criteria.

RESULTS

sOb-R was inversely associated with GDM (odds ratio, 0.76 [95% confidence interval, 0.69-0.83] per ng/ml increase in sOb-R, P < .001) in crude analysis. The association was attenuated after adjustments for covariates and leptin (0.85 [0.77-0.95], P = .004). Compared to women with sOb-R higher than 5 ng/ml, the odds ratio of GDM was 0.29(0.11-0.78; P = .014) among women with sOb-R greater than 10 ng/ml and 0.59 (0.37-0.94; P = .026) among women with sOb-R 5-10 ng/ml, in adjusted analysis. sOb-R levels did not differ across ethnic groups, and sOb-R did not explain ethnic differences in GDM risk.

CONCLUSIONS

There was an independent, inverse association between sOb-R and GDM, with the lowest risk of GDM observed among higher sOb-R concentrations.

Physical fitness is independently related to blood leptin concentration and insulin sensitivity index in male subjects with central adiposity

AIM

To compare the maximal power output (MPO) of subjects presenting a central adiposity to those of controls and to study the links between plasma leptin or indices of insulin sensitivity (QUICKI) and physical fitness (PF).

METHODS

MPO was determined for 169 middle-aged men divided into two groups according to waist circumference (WC- < 94 cm, WC+ ≥ 94 cm) each subdivided in two subgroups with low and high PF (WC-L, WC-H, WC+L, WC+H) determined from the median MPO relative to fat free mass (3.06 W/kg(FFM)).

RESULTS

MPO (W/kg(FFM)) was lower in WC+ than in WC-. Expressed relative to fat mass, leptin was lower and QUICKI higher in WC- than in WC+. In WC+H, leptin and QUICKI were significantly less disturbed than in WC+L and were independently correlated to MPO (r = -0.36 and r = 0.32 respectively; p < 0.001). In WC+, when visceral perimeter was added to the analysis, the relationships MPO/leptin remained significant but not MPO/QUICKI.

CONCLUSION

The low PF in subjects with abdominal obesity is independently linked to plasma leptin and insulin sensitivity even if leptin and insulin may share common pathways in their peripheral effects. Visceral adiposity participates to the link between MPO and QUICKI, but not between MPO and leptin.

Correlation between leptin level and hypertension in normal and obese pre- and postmenopausal women

OBJECTIVE

The present study was aimed at evaluating the correlation between leptin and hypertension in normal and obese hypertensive pre- (Pre-M) and postmenopausal (Post-M) women of Jalandhar city (Punjab, India).

DESIGN

For the present study, 78 Pre-M and Post-M women were recruited in four categories as follows: i) normal normotensive, ii) obese normotensive, iii) normal hypertensive, and iv) obese hypertensive. Body mass index was considered as the index of obesity. Guidelines given by JNC-VII were followed for the assessment of hypertension. Leptin was assayed by sandwich ELISA, and estradiol (E(2)) was assayed by competitive ELISA.

RESULTS

Leptin level was found to be significantly higher in normal Pre-M women (P<0.02) than that of normal Post-M women. Obese subjects had significantly higher leptin level (P<0.001) than the normal women. In the case of hypertensive subjects, leptin level was significantly higher than that of normotensive counterparts. E(2) level was found significantly lower in Post-M women (P<0.001) than that of Pre-M women as well as in hypertensive women than that of normotensive subjects. A positive correlation was observed between blood pressure (BP) and leptin, but significant association was observed in hypertensive normal and obese Pre-M and Post-M women only.

CONCLUSION

It is concluded from the present findings that leptin contributes to the regulation of BP in hypertensive normal as well as in the obese Pre-M and Post-M women. So, leptin may be a regulator of BP in hypertensive women independent of the degree of obesity and the menopausal status.

Leptin, not adiponectin, predicts hypertension in the Copenhagen City Heart Study

BACKGROUND

Leptin and adiponectin are hormones secreted by adipose tissue, and both hormones are candidate intermediaries between adipose tissue and overweight-related diseases. So far, no prospective study has been published where the independent effects of these two hormones on the development of hypertension have been directly compared. The objective of this study was to investigate the relationships between plasma levels of leptin and adiponectin and new-onset hypertension in the Copenhagen City Heart Study (CCHS).

METHODS

In a prospective study design, we examined new-onset hypertension in 620 women and 300 men who were normotensive in the third CCHS examination, which was performed in 1991-1994.

RESULTS

Between the third and the fourth CCHS examination, which was performed in 2001-2003, 254 had developed hypertension, defined as systolic blood pressure (SBP) > or = 140 mm Hg, or diastolic blood pressure (DBP) > or = 90 mm Hg, or use of antihypertensive medication. Using logistic regression analysis, adjusting for age, sex, estimated glomerular filtration rate, triglycerides, high-density lipoprotein cholesterol (HDL-C), fibrinogen, and glucose, and with leptin and adiponectin included in the same model, leptin was significantly associated with new-onset hypertension with an odds ratio (95% confidence interval) of 1.28 (1.08-1.53; P < 0.005) for 1 s.d. higher level of log-transformed leptin, whereas adiponectin was not significantly associated with new-onset hypertension having an odds ratio of 1.02 (0.84-1.24; P = 0.83) for 1 s.d. higher level of log-transformed adiponectin.

CONCLUSIONS

In the CCHS, leptin, but not adiponectin, was a significant independent predictor of new-onset hypertension.

Femoral artery diameter and arteriogenic cytokines in healthy women

Animal studies have identified monocyte chemoattractive protein-1 (MCP-1) and vascular endothelial growth factor (VEGF) as critical mediators of arterial diameter enlargement in response to chronic increases in blood flow (arteriogenesis). Furthermore, cellular studies have shown that the shear stresses resulting from increased blood flow stimulate synthesis of MCP-1, which in turn stimulates synthesis of VEGF. The purpose of this study was to determine if these mechanisms are evident in healthy women. Resting femoral artery diameter and blood flow, lean leg mass, MCP-1 and VEGF concentrations, and aerobic capacity were measured in 34 healthy women along with plasma concentrations of lipids associated with cardiovascular disease risk. Femoral artery diameter was independently related to metabolically active (lean) leg mass (b=0.41, P=0.008) and aerobic capacity (b=0.45, P=0.004). Plasma MCP-1 correlated negatively with the ratio of femoral artery diameter to lean leg mass (b=-0.42, P=0.009) and positively with serum triglycerides (b=0.46, P=0.005). Plasma VEGF exhibited similar correlations and strongly correlated with MCP-1 (R=0.92, P<0.0001). The results indicate that circulating MCP-1 and VEGF concentrations are associated with both arteriogenic and atherogenic stimuli in healthy women.