Hyperleptinemia Is a Risk Factor for the Development of Central Arterial Stiffness in Kidney Transplant Patients

Pro-Inflammatory Profile of Adipokines in Obesity Contributes to Pathogenesis, Nutritional Disorders, and Cardiovascular Risk in Chronic Kidney Disease

Obesity is a disease which leads to the development of many other disorders. Excessive accumulation of lipids in adipose tissue (AT) leads to metabolic changes, including hypertrophy of adipocytes, macrophage migration, changes in the composition of immune cells, and impaired secretion of adipokines. Adipokines are cytokines produced by AT and greatly influence human health. Obesity and the pro-inflammatory profile of adipokines lead to the development of chronic kidney disease (CKD) through different mechanisms. In obesity and adipokine profile, there are gender differences that characterize the male gender as more susceptible to metabolic disorders accompanying obesity, including impaired renal function. The relationship between impaired adipokine secretion and renal disease is two-sided. In the developed CKD, the concentration of adipokines in the serum is additionally disturbed due to their insufficient excretion by the excretory system caused by renal pathology. Increased levels of adipokines affect the nutritional status and cardiovascular risk (CVR) of patients with CKD. This article aims to systematize the current knowledge on the influence of obesity, AT, and adipokine secretion disorders on the pathogenesis of CKD and their influence on nutritional status and CVR in patients with CKD.

Aortic Stiffness: Epidemiology, Risk Factors, and Relevant Biomarkers

Aortic stiffness (AoS) is a maladaptive response to hemodynamic stress and both modifiable and non-modifiable risk factors, and elevated AoS increases afterload for the heart. AoS is a non-invasive marker of cardiovascular health and metabolic dysfunction. Implementing AoS as a diagnostic tool is challenging as it increases with age and varies amongst races. AoS is associated with lifestyle factors such as alcohol and smoking, as well as hypertension and comorbid conditions including metabolic syndrome and its components. Multiple studies have investigated various biomarkers associated with increased AoS, and this area is of particular interest given that these markers can highlight pathophysiologic pathways and specific therapeutic targets in the future. These biomarkers include those involved in the inflammatory cascade, anti-aging genes, and the renin-angiotensin aldosterone system. In the future, targeting AoS rather than blood pressure itself may be the key to improving vascular health and outcomes. In this review, we will discuss the current understanding of AoS, measurement of AoS and the challenges in interpretation, associated biomarkers, and possible therapeutic avenues for modulation of AoS.

Serum leptin levels are positively associated with aortic stiffness in patients with chronic kidney disease stage 3-5

Leptin potentially exerts atherogenic effects.This study evaluated the relationship between serum leptin levels and aortic stiffness in patients with stage 3-5 chronic kidney disease (CKD). Totally 205 participants were enrolled. Fasting blood sample were checked and serum leptin were measured by enzyme immunoassay. Aortic stiffness was measured as the carotid-femoral pulse wave velocity (cfPWV). 73 (35.6%) of 205 patients showed cfPWV >10 m/s were defined as aortic stiffness group. Compared with the remaining patients, the aortic stiffness group had high prevalence of diabetes mellitus, older age, higher waist circumference, body fat mass, systolic blood pressure, fasting glucose, and higher serum leptin level. In multivariable logistic regression analysis the independent predictors of cfPWV >10 m/s included leptin levels (odds ratio [OR]: 1.061, 95% confidence interval [CI]: 1.027-1.095, P < 0.001), age (OR: 1.064, 95% CI: 1.033-1.096, P< 0.001), and systolic blood pressure (OR: 1.021, 95% CI: 1.006-1.037, P = 0.006). Multivariable forward stepwise linear regression analysisshowed a positive association between log-transformed leptin levels and log-cfPWV (β = 0.192, adjusted R² change = 0.042, P = 0.001). Thus, aortic stiffness is positively correlated with serum leptin levels in patients with stage 3-5 CKD.Abbreviations: BUN, blood urea nitrogen; cfPWV, carotid-femoral pulse wave velocity; CI, confidence interval; CKD, chronic kidney disease; Cre, creatinine; DBP, diastolic blood pressure; DM, diabetes mellitus; eGFR, estimated glomerular filtration rate; LDL-C, low-density lipoprotein cholesterol; OR, odds ratio; SBP, systolic blood pressure; TCH, total cholesterol; TG, triglycerides.

Lower Serum Fibroblast Growth Factor 21 Levels are Associated with Normal Lumbar Spine Bone Mineral Density in Hemodialysis Patients

Recent evidence has indicated that fibroblast growth factor 21 (FGF21) regulates longitudinal bone growth, with increased FGF21 levels leading to bone loss. The present study evaluated the relationship between bone mineral density (BMD) and serum FGF21 levels in patients undergoing hemodialysis (HD). We analyzed blood samples from 95 patients undergoing HD and measured BMD using dual-energy X-ray absorptiometry of the lumbar vertebrae (L2–L4). Serum FGF21 concentrations were determined using a commercially available enzyme-linked immunosorbent assay kit. Thirteen (11.6%) patients were found to have osteoporosis, 27 (28.4%) osteopenia, and 57 patients had normal BMD. Advanced age and decreased body mass index, height, body weight, waist circumference, and triglyceride level were associated with lower lumbar T-scores, as were increased alkaline phosphatase, urea reduction rate, fractional clearance index for urea, and FGF21 levels. Low log-FGF21, increased body mass index, increased pre-HD body weight, and increased logarithmically transformed triglycerides (log-TG) were found to be significantly and independently associated with lumbar BMD by multivariate forward stepwise linear regression analysis with adjustment for significant confounders. We conclude that high serum FGF21 level is negatively associated with BMD in patients undergoing HD.

Constitutive interpretation of arterial stiffness in clinical studies: a methodological review

Clinical assessment of arterial stiffness relies on noninvasive measurements of regional pulse wave velocity or local distensibility. However, arterial stiffness measures do not discriminate underlying changes in arterial wall constituent properties (e.g., in collagen, elastin, or smooth muscle), which is highly relevant for development and monitoring of treatment. In arterial stiffness in recent clinical-epidemiological studies, we systematically review clinical-epidemiological studies (2012–) that interpreted arterial stiffness changes in terms of changes in arterial wall constituent properties (63 studies included of 514 studies found). Most studies that did so were association studies (52 of 63 studies) providing limited causal evidence. Intervention studies (11 of 63 studies) addressed changes in arterial stiffness through the modulation of extracellular matrix integrity (5 of 11 studies) or smooth muscle tone (6 of 11 studies). A handful of studies (3 of 63 studies) used mathematical modeling to discriminate between extracellular matrix components. Overall, there exists a notable gap in the mechanistic interpretation of stiffness findings. In constitutive model-based interpretation, we first introduce constitutive-based modeling and use it to illustrate the relationship between constituent properties and stiffness measurements (“forward” approach). We then review all literature on modeling approaches for the constitutive interpretation of clinical arterial stiffness data (“inverse” approach), which are aimed at estimation of constitutive properties from arterial stiffness measurements to benefit treatment development and monitoring. Importantly, any modeling approach requires a tradeoff between model complexity and measurable data. Therefore, the feasibility of changing in vivo the biaxial mechanics and/or vascular smooth muscle tone should be explored. The effectiveness of modeling approaches should be confirmed using uncertainty quantification and sensitivity analysis. Taken together, constitutive modeling can significantly improve clinical interpretation of arterial stiffness findings.

High serum leptin levels are associated with central arterial stiffness in geriatric patients on hemodialysis

OBJECTIVE

Central arterial stiffness predicts cardiovascular (CV) mortality in hemodialysis (HD) patients. The aging process transforms lipid distribution and thus alters adipokine secretion. The harmful effects of leptin on CV events may change in the elderly. The purpose of this study was to investigate the relationship between leptin and central arterial stiffness markers through carotid-femoral pulse wave velocity (cfPWV) in geriatric HD patients.

MATERIALS AND METHODS

Patients over 65 years old on chronic HD were recruited. Blood samples were collected, and the cfPWV was measured with the SphygmoCor system. The patients with cfPWV values >10 m/s were defined as the high arterial stiffness group.

RESULTS

In total, 30 (51.7%) of the 58 geriatric patients on chronic HD in this study were in the high arterial stiffness group. The high arterial stiffness group had higher rates of diabetes mellitus (P = 0.019), hypertension (P = 0.019), and higher systolic blood pressure (P = 0.018), pulse pressure (P = 0.019), body mass index (P = 0.018), serum leptin levels (P = 0.008), and hemoglobin levels (P = 0.040) than those in the low arterial stiffness group. Multivariable forward stepwise linear regression analysis showed logarithmically transformed leptin (log-leptin, β =0.408, adjusted R 2 change = 0.164; P = 0.001) and diabetes (β =0.312, adjusted R 2 change = 0.085; P = 0.009) were associated with cfPWV values in geriatric HD patients. Moreover, an increased serum leptin level (odds ratio: 1.053; 95% confidence interval: 1.007-1.100; P = 0.023) was an independent factor for central arterial stiffness among geriatric HD patients after multivariate logistic regression analysis.

CONCLUSION

In this study, a higher serum leptin level was correlated with central arterial stiffness in geriatric HD patients.

Hyperleptinemia is associated with the aortic augmentation index in kidney transplant recipients

Objective

Increased circulating leptin, a marker of leptin resistance, is common in patients with obesity and is also an independent factor in prediction of cardiovascular disease. The aim of this study was to evaluate the relationship between fasting serum leptin levels and the aortic augmentation index (AIx) in kidney transplant recipients.

Materials and Methods

Fasting blood samples were obtained from 70 kidney transplant recipients. The aortic AIx was measured using a validated tonometry system (SphygmoCor). Plasma leptin levels were measured using a commercial enzyme-linked immunosorbent assay kit.

Results

Simple linear analysis of the aortic AIx in kidney transplant recipients showed that body fat mass (P = 0.002), diastolic blood pressure (DBP) (P = 0.020), logarithmically transformed triglycerides (P = 0.035), and leptin (P < 0.001) were positively correlated, while height (P = 0.004) and the glomerular filtration rate (P = 0.022) were negatively correlated with the aortic AIx in kidney transplant recipients. Forward stepwise linear regression analysis of the factors significantly associated with the aortic AIx showed that leptin (P < 0.001), DBP (P = 0.014), and body height (P = 0.036) were independent predictors of the aortic AIx in kidney transplant recipients.

Conclusion

These results suggest that the serum fasting leptin level is associated with the aortic AIx in kidney transplant recipients.

Leptin, cardiovascular diseases and type 2 diabetes mellitus

Leptin, an adipokine that is implicated in the control of food intake via appetite suppression, may also stimulate oxidative stress, inflammation, thrombosis, arterial stiffness, angiogenesis and atherogenesis. These leptin-induced effects may predispose to the development of cardiovascular diseases. In the present review we discuss the evidence linking leptin levels with the presence, severity and/or prognosis of both coronary artery disease and non-cardiac vascular diseases such as stroke, carotid artery disease, peripheral artery disease (PAD) and abdominal aortic aneurysms (AAA) as well as with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). Leptin levels have been positively associated with the presence, severity, extent and lesion complexity of coronary atherosclerosis as well as with the presence, severity and poor clinical outcomes of both ischemic and hemorrhagic strokes. But conflicting results also exist. Furthermore, leptin was reported to independently predict common carotid intima-media thickness and carotid plaque instability. A link between hyperleptinemia and PAD has been reported, whereas limited data were available on the potential association between leptin and AAA. Elevated leptin concentrations have also been related to CKD incidence and progression as well as with insulin resistance, T2DM, micro- and macrovascular diabetic complications. Statins and antidiabetic drugs (including sitagliptin, metformin, pioglitazone, liraglutide and empagliflozin) may affect leptin levels. Further research is needed to establish the potential use (if any) of leptin as a therapeutic target in these diseases.

High serum leptin level is associated with peripheral artery disease in adult peritoneal dialysis patients

Objective:

Peripheral artery disease (PAD) is associated with systemic atherosclerosis and indicates an increased risk of mortality in peritoneal dialysis (PD) patients. A high leptin level accelerates atherosclerosis in apoE-deficient mice. The purpose of this study was to examine the association of serum leptin level and PAD in adult PD patients.

Materials and Methods:

The clinical characteristics of sixty PD patients recruited from June 2015 to October 2016 were obtained. Serum leptin concentrations were determined. Ankle–brachial index (ABI) values were measured and those with a left or right ABI <0.9 were defined as the low ABI group.

Results:

Twenty of these 60 PD patients (33.3%) had diabetes mellitus and 32 patients (53.3%) had hypertension. Thirteen PD patients (21.7%) were in the low ABI group. Higher serum leptin (P = 0.002) and C-reactive protein (CRP, P < 0.001) levels were found in the low ABI group compared with those in the normal ABI group. More number of patients with diabetes (P = 0.015) and current smokers (P = 0.037) were noted in the low ABI group than in the normal ABI group. After adjustment for factors that were significantly associated with PAD in multivariate logistic regression analysis, each increase of 1 ng/mL in the serum leptin level (odds ratio [OR], 1.062; 95% confidence interval [CI], 1.014–1.114; P = 0.012) and each increase of 0.1 mg/dL in the serum CRP level (OR, 1.107; 95% CI, 1.011–1.211; P = 0.028) were found to be independent predictors of PAD in PD patients.

Conclusion:

Higher serum leptin and CRP levels correlated positively with the diagnosis of PAD in PD patients.

Serum leptin is a predictor for central arterial stiffness in hypertensive patients

AIM

Serum adipokines have a role in the development of arterial stiffness. We aimed to investigate the risk factors of developing arterial stiffness and the association of leptin and arterial stiffness in hypertensive (HTN) patients.

METHODS

There were 101 HTN patients enrolled. Fasting blood samples and baseline characteristics were obtained and carotid-femoral pulse wave velocity (cfPWV) was measured with the SphygmoCor system. A cfPWV > 10 m/s was defined as high arterial stiffness, and ≤ 10 m/s as low arterial stiffness.

RESULT

Forty-seven patients (46.5 %) had high arterial stiffness, and had a higher percentage of diabetes (P = 0.044), , older age (P < 0.001), higher pulse pressure (P = 0.049), and higher serum blood urea nitrogen (P = 0.029), creatinine (P = 0.027), intact parathyroid hormone (P = 0.004), serum leptin level (P = 0.002), C-reactive protein (P < 0.001), but lower estimated glomerular filtration rate (P = 0.006) compared to patients with low arterial stiffness. After adjusting for factors significantly associated with arterial stiffness by multivariate logistic regression analysis, it revealed that leptin (aOR = 1.037, 95% CI = 1.007-1.067, P = 0.014), having DM (aOR = 4.885, 95% CI = 1.590-15.006, P = 0.006), and elevated CRP (aOR = 1.503, 95% CI = 1.110-2.0371,P = 0.009) were significant independent predictors of arterial stiffness in HTN patients.

CONCLUSIONS

Serum leptin level could be a predictor for arterial stiffness in HTN patients.

Hyperleptinemia positively associated with central arterial stiffness in hemodialysis patients

Objective

Leptin plays a role in stimulating vascular inflammation, vascular smooth muscle hypertrophy, and augmenting blood pressure, which contributes to the pathogenesis of atherosclerosis and leads to arterial stiffness. This vascular damage, measured by carotid-femoral pulse wave velocity (cfPWV), is recognized as an independent predictor of cardiovascular mortality in hemodialysis (HD) patients. The aim of this study was to evaluate the relationship between serum leptin and arterial stiffness in HD patients.

Patients and methods

In 112 of the 126 HD patients were eligible and their biochemical data were collected for analysis. Serum leptin level was measured using a commercial enzyme-linked immunosorbent assay kit. Carotid-femoral pulse wave velocity was measured by a validated tonometry system (SphygmoCor). Those have cfPWV values above 10 m/s are defined as the high arterial stiffness group.

Results

Among the participants, thirty-eight of them who were in the high arterial stiffness group, had a higher prevalence of diabetes mellitus (p = 0.002), age (p = 0.029), body mass index (BMI, p = 0.018), body fat mass (p = 0.001), hemoglobin (p = 0.040), and serum leptin levels (P<0.001). Multivariable logistic regression analysis showed that leptin (odds ratio [OR] 1.09; 95% confidence interval [CI] 1.04–1.14; p <0.001), diabetes (OR 7.17; CI 1.39–37.00; p = 0.019), body fat mass (OR 1.16; CI 1.02–1.33; p = 0.027); and hemoglobin (OR 2.11; CI 1.15–3.87; p = 0.015) were independently associated with arterial stiffness in HD patients.

Conclusion

In our study, hyperleptinemia was positively correlated to the high cfPWV and thus was related to high arterial stiffness in HD patients.

Positive correlation of serum leptin levels and peripheral arterial stiffness in patients with type 2 diabetes

Objective:

Leptin plays a pathophysiologic role in the pathogenesis of aortic dysfunction and peripheral arterial stiffness (PAS). Our aim was to evaluate the risk factors for developing PAS and the association of leptin and PAS in patients with type 2 diabetes mellitus (DM).

Materials and Methods:

Fasting blood samples were obtained for biochemical data and leptin determinations from 105 patients with type 2 DM. In this study, we applied an automatic pulse wave analyzer (VaSera VS-1000) to measure the brachial-ankle pulse wave velocity (baPWV); a baPWV value >14.0 m/s on either side was considered high PAS.

Results:

Seventy-five patients (71.4%) had high PAS and they included a higher percentage of patients with hypertension (P < 0.001), older age (P < 0.001), and a higher body fat mass (P = 0.043), systolic blood pressure (P < 0.001), diastolic blood pressure (P = 0.016), serum blood urea nitrogen (P = 0.003), and leptin level (P < 0.001), and lower height (P = 0.027) and glomerular filtration rate (P < 0.001) compared with type 2 DM patients with low PAS. After adjusting for factors significantly associated with PAS in these patients by multivariate logistic regression analysis, age (β = 0.470, adjusted R² change = 0.279; P < 0.001), logarithmically transformed leptin (log-leptin, β = 0.259, adjusted R² change = 0.085; P = 0.001), and hypertension (β = 0.197, adjusted R² change = 0.031; P = 0.011) were significant independent predictors of PAS in type 2 DM patients.

Conclusion:

The serum leptin level could be a predictor of PAS in type 2 DM patients.

The intriguing connections of leptin to hyperparathyroidism

PURPOSE

Leptin has been implicated in bone metabolism, but the association with parathyroid gland function has not been fully clarified. This review aimed to summarize evidence of the association between leptin and hyperparathyroidism, both primary and secondary, elucidating the potential pathophysiologic and therapeutic consequences between leptin and parathyroid hormone, hopefully prompting the design of new studies.

RESULTS

Experimental studies indicate a positive loop between leptin and parathyroid hormone in primary hyperparathyroidism. Dissimilar, parathyroid hormone seems to inhibit leptin expression in severe secondary hyperparathyroidism. Data from clinical studies indicate higher leptin levels in patients with primary hyperparathyroidism than controls, but no association between parathyroid hormone and leptin levels, as well as a minimal or neutral effect of parathyroidectomy on leptin levels in patients with primary hyperparathyroidism. Clinical data on secondary hyperparathyroidism, mainly derived from patients with chronic kidney disease, indicate a potential inverse association between leptin and parathyroid hormone in some, but not all studies. This relationship may be affected by the diversity of morbidity among these patients.

CONCLUSIONS

Data from experimental studies suggest a different association between leptin and parathyroid hormone in primary and secondary hyperparathyroidism. Data from clinical studies are conflicting and potentially affected by confounders. More focused, well-designed studies are warranted to elucidate a potential association between leptin and parathyroid hormone, which may have specific clinical implications, i.e., targeting obesity and hyperleptinemia in patients with hyperparathyroidism.

High serum adipocyte fatty acid binding protein level as a potential biomarker of aortic arterial stiffness in hypertensive patients with metabolic syndrome

BACKGROUND

The adipocyte-fatty-acid-binding protein (A-FABP) has been implicated in arterial stiffness, metabolic syndrome (MetS), and cardiovascular disease. We aimed to determine the relationship among serum A-FABP concentration, cardiometabolic risk factors, and central arterial stiffness in a hypertensive population.

METHODS

Fasting blood samples and baseline characteristics were obtained from 110 hypertensive patients. Serum A-FABP concentrations were determined by enzyme immunoassay kit. High arterial stiffness was defined as carotid-femoral pulse wave velocity values >10m/s via the SphygmoCor system.

RESULTS

Patients with MetS and high arterial stiffness accounted for 67.3% and 42.7% of the study population, respectively. Serum A-FABP was positively associated with MetS and high arterial stiffness (P=0.006 and P<0.001, respectively). Multivariable stepwise linear regression analysis of the significant variables of arterial stiffness revealed that logarithmically transformed A-FABP (log-A-FABP, β=0.278, P=0.002) was positively correlated arterial stiffness in hypertensive patients. Subgroup analysis revealed that log-A-FABP (β=0.327, P=0.003), age (β=0229, P=0.032), and triglyceride (β=0.307, P=0.004) were significantly positively correlated with arterial stiffness in hypertensive patients with MetS.

CONCLUSIONS

Elevated A-FABP concentration could be a predictor for MetS and arterial stiffness in hypertensive patients.

Leptin is an independent marker of metabolic syndrome in elderly adults with type 2 diabetes

OBJECTIVE

It is well established that patients with metabolic syndrome (MetS) demonstrate elevated levels of serum leptin. The aim of this study is to identify fasting serum leptin as an independent marker of MetS in geriatric diabetic patients.

MATERIALS AND METHODS

Sixty-four patients over 65 years old with type 2 diabetic mellitus (T2DM) were assessed for MetS based on the diagnostic criteria of the International Diabetes Federation. Fasting blood samples including serum leptin concentrations were obtained from the participants. Leptin levels were determined using a commercial enzyme immunoassay.

RESULTS

Forty-five (70.3%) of the 64 geriatric T2DM patients enrolled in this study were found to have MetS. This group of participants compared with those in the non-MetS group had higher serum levels of leptin (P = 0.004), triglycerides (P = 0.005), fasting glucose (P = 0.049), glycated hemoglobin (P = 0.016), white blood cells (P = 0.003), C-reactive protein (CRP, P = 0.028), insulin (P < 0.001), higher homeostatic model assessment insulin resistance values (HOMA1-IR and HOMA2-IR, both P < 0.001), a higher body weight (P = 0.024), body mass index (P < 0.001), body fat mass (P < 0.001), waist circumference (P < 0.001), systolic blood pressure (BP) (P < 0.001), diastolic BP (P < 0.001), percentage of women (P = 0.011), prevalence of hypertension (P = 0.042), and a lower level of serum high-density lipoprotein cholesterol (P = 0.001). Univariate linear analysis of the clinical variables associated with the fasting serum leptin level revealed that height (P = 0.020) had a negative correlation, while body fat mass (P < 0.001) and logarithmically transformed CRP (log-CRP, P < 0.001) had positive correlations with serum leptin levels. Multivariate forward step-wise linear regression analysis of the variables significantly associated with fasting serum leptin levels showed that body fat mass (P < 0.001) and log-CRP (P = 0.001) were independent predictors of these values.

CONCLUSION

Serum leptin is positively correlated with MetS. It serves as an independent marker of MetS in elderly patients with T2DM.

Serum leptin level positively correlates with metabolic syndrome among elderly Taiwanese

Objective:

Leptin is an adipocyte-derived hormone and has shown positive correlation with obesity and metabolic syndrome (MetS) in many studies. However, there are few studies investigating this relation in elderly people. Therefore, we aimed to investigate the correlation between the fasting serum leptin level and MetS among older Taiwanese.

Materials and Methods:

The fasting serum leptin level was obtained from 62 Taiwanese participants over 65 years old and was measured using a commercially available enzyme immunoassay kit. MetS and its components were defined using diagnostic criteria from the International Diabetes Federation.

Results:

Thirty elderly participants (48.4%) had MetS. The serum leptin level was positively correlated with MetS (P < 0.001). Multivariate logistic regression analysis of the factors significantly associated with MetS showed that logarithmically transformed leptin (log-leptin, each increase 0.1 ng/mL log-leptin, odds ratio: 1.276, 95% confidence interval: 1.015–1.603, P = 0.037) was still an independent predictor of MetS in elderly persons. Univariable linear analysis showed that body weight (r = 0280, P = 0.028), body mass index (r = 0.417, P = 0.001), waist circumference (r = 0.419, P = 0.001), blood urea nitrogen (r = 0255, P = 0.046), log-insulin (r = 0436, P < 0.001), and logarithmically transformed homeostasis model assessment of insulin resistance (r = 0359, P = 0.004) positively correlated with fasting serum log-leptin levels. Multivariate forward stepwise linear regression analysis of the factors significantly associated with fasting serum log-leptin levels revealed that waist circumference (adjusted R² = 0.083, P = 0.002), statin use (adjusted R² = 0.058, P = 0.016), and female gender (adjusted R² = 0.041, P = 0.034) were independent predictors of fasting serum log-leptin levels among elderly participants.

Conclusion:

In elderly Taiwanese, the serum leptin level was positively correlated with MetS. Waist circumference, statin use, and female gender were independent predictors of the fasting serum leptin level in elderly participants.

Association of hyperleptinemia with peripheral arterial disease in hypertensive patients

Objective:

Hypertension is a risk factor for peripheral artery disease (PAD). Serum leptin plays an important role in promoting endothelial dysfunction. The aim of this study is to investigate whether the leptin level is associated with PAD in hypertensive patients.

Materials and Methods:

Ninety-eight hypertensive patients were enrolled in this study. Ankle-brachial index (ABI) values were measured using an automated oscillometric device. Patients with an ABI value <0.9 were considered the low ABI group. C-reactive protein (CRP) was measured using standard enzymatic automated methods. Serum levels of human leptin were determined using a commercially available enzyme immunoassay.

Results:

Eighteen (18.4%) hypertensive patients were included in the low ABI group. Hypertensive patients in the low ABI group had higher serum creatinine (P < 0.001), CRP (P = 0.003), and leptin (P < 0.001) levels, higher prevalence of diabetes (P = 0.036), and current smoking (P = 0.034) than patients in the normal ABI group. Univariate linear regression analyses revealed that body weight (P = 0.014), waist circumference (P = 0.010), body mass index (P = 0.002), and logarithmically transformed CRP (log-CRP, P = 0.001) were positively correlated with serum log-leptin levels in hypertensive patients. Multivariate stepwise linear regression analysis showed that log-leptin (β = 0.439, adjusted R² change = 0.224, P < 0.001) was also an associated factor of PAD in hypertensive patients.

Conclusion:

A higher log-leptin value is an independent predictor of PAD in hypertensive patients.

The association of serum leptin levels with metabolic diseases

Leptin is a 167-amino-acid protein released by white adipose tissue and encoded by the obese gene. It has a role as a negative regulator of appetite control through sending a satiety signal to act on receptors within the hypothalamus. At normal levels, leptin can exert its effects on weight regulation according to white fat mass, induce sodium excretion, maintain vascular tone, and repair the myocardium. Beyond these effects, elevated serum leptin levels have been implicated in the pathogenesis of metabolic syndrome, diabetes mellitus, hypertension, and multiple cardiovascular diseases. In addition, hyperleptinemia had been reported to contribute to renal diseases through multiple mechanisms resulting in glomerulopathy presenting with a decreased glomerular filtration rate, increased albuminuria, and related clinical symptoms, which are pathophysiological features of chronic kidney disease. Because these cardiovascular and metabolic disorders are great challenges for physicians, understanding the related pathophysiological association with leptin might become a valuable aid in handling patients in daily clinical practice. This review will discuss the roles of leptin in the regulation of biological functions of multiple organs beyond the maintenance of feeding and metabolism.

Adiponectin, leptin, nitric oxide, and C-reactive protein levels in kidney transplant recipients: comparison with the hemodialysis and chronic renal failure

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in patients with chronic kidney disease (CKD) including kidney transplant recipients (KTR). Secondary lipid metabolism disorders, endothelial dysfunction, and inflammation enhance the risk of CVD development in these patients. The aim of the present study was to investigate the lipid profile, adiponectin, leptin, nitric oxide (NO), and high sensitivity C-reactive protein (hs-CRP) levels in KTR and to compare these parameters with those of the patients with chronic renal failure (CRF), hemodialysis (HD) patients, and healthy controls.

METHODS

Serum adiponectin and leptin levels were measured by radioimmunoassay; hs-CRP was determined immunoturbidimetrically. Determination of NO was based on the Griess reaction.

RESULTS

Compared with the control group, serum NO and adiponectin levels were significantly higher in the KTR, CRF, and HD groups; hs-CRP levels were significantly higher in the KTR and HD groups; leptin levels were significantly higher in the KTR. In addition, serum NO level was significantly higher in the KTR compared to CRF cases. Adiponectin correlated positively with high density lipoprotein-cholesterol in the control and patient groups. A positive correlation was observed between hs-CRP and NO in the KTR and the patients with CRF. Serum adiponectin levels were inversely correlated with hs-CRP and leptin in the HD group.

CONCLUSION

KTR suffer from inflammation and accompanying changes in levels of adipocytokines and NO which contribute to the increased risk of CVD in these patients.