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Plasma leptin concentration, insulin sensitivity, and 24-hour ambulatory blood pressure and left ventricular geometry
G Paolisso1, M R Tagliamonte, M Galderisi
1Department of Geriatric Medicine, University of Naples Federico II, Italy. gpaoliss@tin.it
Insights
In hypertensive men, fasting plasma leptin levels significantly influence myocardial wall thickness, independent of 24-hour blood pressure. This finding highlights leptin
Area of Science:
- Cardiology
- Endocrinology
- Hypertension Research
Background:
- Left ventricular (LV) hypertrophy is a key predictor of cardiovascular events in hypertensive patients.
- Both hemodynamic (blood pressure) and metabolic factors (e.g., leptin) are implicated in LV hypertrophy.
- The independent role of plasma leptin on LV geometry, separate from blood pressure, requires clarification.
Purpose of the Study:
- To investigate if plasma leptin levels are associated with LV wall thickness in hypertensive men.
- To determine if this association is mediated by 24-hour blood pressure (BP) values.
- To explore independent predictors of myocardial wall thickness in this population.
Main Methods:
- Thirty-six newly diagnosed hypertensive males underwent Doppler echocardiography.
- 24-hour ambulatory BP monitoring and metabolic assessments (glucose clamp, plasma leptin) were performed.
- Statistical analyses, including multiple linear regression, were used to assess relationships.
Main Results:
- Left ventricular mass correlated with ambulatory diastolic BP.
- Myocardial wall thickness indices correlated with diastolic BP, glucose, leptin, and insulin action.
- Plasma leptin, insulin action, and nighttime diastolic BP were independently associated with myocardial wall thickness.
Conclusions:
- Fasting plasma leptin levels are a significant determinant of myocardial wall thickness in hypertensive men.
- This effect is independent of 24-hour blood pressure values.
- Leptin's role in cardiac remodeling warrants further investigation in hypertension.
Abstract:
Left ventricular (LV) hypertrophy is an important predictor of cardiovascular morbidity and mortality. Hemodynamic factors, such as 24-h blood pressure (BP) values, are responsible for left ventricular hypertrophy in hypertensives. On the other hand, some metabolic factors have also been suggested to affect LV mass and geometry. In particular, plasma leptin concentrations have been found associated to LV myocardial growth. Because chronic leptin infusion stimulates sympathetic nervous system activity and increases BP levels, the role of 24-h BP values on leptin-related changes in myocardial wall geometry cannot be ruled out. Thus, the aim of our study was to evaluate whether the relationship between plasma leptin levels and LV wall thickness is mediated by 24-h BP values in hypertensive male patients. Thirty-six newly diagnosed hypertensive patients underwent Doppler echocardiographic examination, 24-h ambulatory BP recording, and metabolic (euglycemic hyperinsulinemic glucose clamp and fasting plasma leptin levels) measurements. Left ventricular mass correlated positively only with ambulatory diastolic BP (DBP) values, whereas the indices of myocardial wall growth such as interventricular septum thickness and sum of wall thickness (ie, septal + posterior wall thickness) correlated either with 24 h, daytime, or nighttime DBP, as well as with fasting plasma glucose, fasting plasma leptin, and insulin action after adjustment for age, body mass index (BMI), and waist/hip ratio (WHR). In contrast, plasma leptin concentration did not correlate with clinical and ambulatory BP values. A multiple linear regression analysis allowed to investigate the independent role of main anthropometric and cardiovascular covariates on the sum of wall thickness variability. A model that includes age, BMI, WHR, fasting plasma leptin concentration, plasma Na+ concentration, insulin action, and nighttime DBP explained 68% of the sum of wall thickness variability. In such a model, plasma leptin concentration (P < .001), insulin action (P < .029), and nighttime DBP (P < .002) were significantly and independently associated with myocardial wall thickness. In conclusion, our study demonstrates that in hypertensive men fasting plasma leptin levels are determinant of myocardial wall thickness independently of 24-h BP values.