Serum leptin levels positively correlate with peripheral arterial stiffness in kidney transplantation patients

Exploring the link between leptin levels and metabolic syndrome in elderly Indian patients: Implications for family medicine and primary care practices

Background

The metabolic syndrome (MetS), according to the Adult Treatment Panel III of the National Cholesterol Education Programme, is a collection of metabolic abnormalities that includes one, two, or all three of the following traits: obesity in the abdomen, dyslipidemia, hypertension, fasting blood sugar, or insulin resistance. This study's aim was to assess the relationship between fasting serum leptin and MetS in elderly adults with T2DM in the Northern Indian population.

Material and Methods

The following information was collected from all the participants: (1) anthropometric data, (2) biochemical data, and (3) a lifestyle questionnaire on sociodemographic data, dietary practices, smoking, and alcohol intake to identify their risk factors for diabetes mellitus, CVD, and hypertension.

Results

A total of 36 older participants (56.30%) had a history of hypertension, while 29 elderly participants (44.61%) had diabetes mellitus. A total of 32 elderly participants (49.2%) had MetS, and this group had higher serum leptin (P 0.003), body weight (P = 0.019), BMI (P 0.001), waist circumference (P 0.001), CRP (P = 0.021), insulin (P = 0.001), and HOMA-IR (P = 0.003) values as well as higher percentages of females (P = 0.001), and those with type 2 diabetes mellitus (P = 0.002) and hypertension (P = 0.039) than those in the non-MetS group.

Conclusion

In older persons with T2DM, our study discovered a favorable correlation between serum leptin and MetS. It can act as a standalone indicator of MetS, offering a way to spot populations at risk for associated consequences and enabling early intervention.

Adipokines and coronary artery calcification in incident dialysis participants

PURPOSE

Adipokines have been associated with increased risk of cardiovascular disease. Our aim was to determine if adipokine levels are associated with coronary artery calcification (CAC) as well as all-cause mortality in incident dialysis patients.

METHODS

In patients new to dialysis, we prospectively investigated the association of adiponectin, leptin and resistin with coronary artery calcification measured by ECG-gated computer tomography. Participants were recruited a median of two months after starting dialysis.

RESULTS

The mean age was 50.0 (12.6) years and 31.1% were women. About 42% percent had BMI > 30. Higher adiponectin levels were inversely associated with CAC progression as change in Agatston score [-155.1 (-267.9, -42.2), p = 0.008] or change in CAC volumes between scans [-2.8 (-4.9, -0.6), p = 0.01]. Higher leptin levels were associated with CAC progression [110.4 (34.3-186.6), p = 0.005]. Decreased leptin [HR 0.5 (0.3-0.9), p = 0.05] was associated with all-cause mortality in adjusted models. There was no significant association between all-cause mortality and adiponectin [1.4 (0.6-3.4), p = 0.4] or resistin [HR 1.7 (0.5-5.0), p = 0.4].

CONCLUSION

High adiponectin protects against CAC progression, but is not associated with increased all-cause mortality. Higher leptin, as well as higher leptin to adiponectin ratio, is associated with CAC progression. Lower leptin levels were associated with all-cause mortality. The association of adipokines and cardiovascular disease in individuals on dialysis is complex and requires further study.

Serum leptin concentration can predict cardiovascular outcomes and all-cause death in maintenance hemodialysis patients

BACKGROUND

We explored the associations between serum leptin concentration and cardiovascular prognosis in maintenance hemodialysis patients.

METHODS

In our prospective study with no intervention, demographics data at baseline were collected from electronic medical records. Serum leptin concentration was determined by ELISA. Patients underwent body composition assessment and echocardiographic measurements after hemodialysis. The primary endpoints were defined as cardiovascular events (CVEs), cardiovascular death (CVD) and all-cause death.

RESULTS

A total of 165 eligible patients aged 51(43-65) y were enrolled and the mean serum leptin concentration was 35.49 (29.98) ng/ml. During a median follow-up of 18 (12-22) months, CVEs occurred in 37 (22.42%) patients and the cardiovascular and all-cause mortality was 10.91% and 21.82%. Serum leptin concentration was associated with CVEs (HR = 0.982, p = 0.003), CVD (HR = 0.934, p = 0.002) and all-cause death (HR = 0.943, p < 0.001). Decreased serum leptin concentration was an independent risk factor for the development of left ventricular hypertrophy (LVH, OR = 0.98, p = 0.007) and peripheral vascular disease (PVD, OR = 0.974, p = 0.007).

CONCLUSION

Serum leptin concentration can independently predict cardiovascular outcomes and all-cause death in MHD patients. The effects that serum leptin concentration on development of LVH and PVD maybe the potential mechanism.

Low Serum 3-Methylhistidine Levels Are Associated With First Hospitalization in Kidney Transplantation Recipients

BACKGROUND

Low protein intake and increased muscle breakdown are associated with increased mortality risk in patients with kidney transplantation (KT). 3-methylhistidine (3-MH), a nonproteinogenic amino acid residue, is an index of muscle breakdown. the present study investigated the association between serum 3-MH levels and subsequent first hospitalization events in patients with KT.

METHODS

A total of 64 KT patients were enrolled and 43 first hospitalization events occurred. Fasting blood samples were obtained and serum 3-MH level was performed with high-performance liquid chromatography and mass spectrometry. Associations between serum 3-MH levels and first hospitalization over a 5-year follow-up period were examined.

RESULTS

Compared with patients without hospitalization, the 64 patients with KT revealed higher diabetes (P = .012) and hypertension (P = .006) prevalence, higher body fat mass (P = .012) and systolic blood pressure (P = .002), higher serum blood urea nitrogen (BUN) levels (P = .003), and lower serum 3-MH levels (P = .001). Statistical analysis revealed that serum 3-MH (95% confidence interval [CI]: 0.902-0.986, P = .010) and serum BUN (95% CI: 1.003-1.040, P = .022) levels were independently associated with first hospitalization events in patients with KT. Kaplan-Meier analysis showed a greater cumulative incidence of first hospitalization events in the patients with lower 3-MH levels (≤5.91 ng/mL) than that in those with higher 3-MH levels (P = .014; log-rank test).

CONCLUSIONS

Low serum 3-MH levels are associated with increased first hospitalization risk in KT recipients.

Epicardial Adipose Tissue, Adiponectin and Leptin: A Potential Source of Cardiovascular Risk in Chronic Kidney Disease

The importance of cardiometabolic factors in the inception and progression of atherosclerotic cardiovascular disease is increasingly being recognized. Beyond diabetes mellitus and metabolic syndrome, other factors may be responsible in patients with chronic kidney disease (CKD) for the high prevalence of cardiovascular disease, which is estimated to be 5- to 20-fold higher than in the general population. Although undefined uremic toxins are often blamed for part of the increased risk, visceral adipose tissue, and in particular epicardial adipose tissue (EAT), have been the focus of intense research in the past two decades. In fact, several lines of evidence suggest their involvement in atherosclerosis development and its complications. EAT may promote atherosclerosis through paracrine and endocrine pathways exerted via the secretion of adipocytokines such as adiponectin and leptin. In this article we review the current knowledge of the impact of EAT on cardiovascular outcomes in the general population and in patients with CKD. Special reference will be made to adiponectin and leptin as possible mediators of the increased cardiovascular risk linked with EAT.

Association of Low Serum l-Carnitine Levels with Peripheral Arterial Stiffness in Patients Who Undergo Kidney Transplantation

l-carnitine is an important co-factor in fatty-acid metabolism, and its deficiency is associated with insulin resistance, which is independently associated with arterial stiffness. This study evaluated the relationship between serum l-carnitine level and peripheral arterial stiffness (PAS) in kidney transplantation (KT). Fasting blood samples were collected from 65 patients who underwent KT. We measured the brachial–ankle pulse wave velocity, and 36 patients (55.4%) had PAS. Patients with PAS had a significantly higher percentage of diabetes (p = 0.001), hypertension (p = 0.033), and metabolic syndrome (p = 0.044); higher waist circumference (p = 0.010), systolic blood pressure (p = 0.002), serum triglyceride level (p = 0.040), insulin level (p = 0.002), and homeostasis model assessment of insulin resistance (p = 0.002); lower high-density lipoprotein cholesterol (p = 0.036) and serum l-carnitine levels (p < 0.001); older age (p = 0.041); and a longer KT duration (p = 0.025) than those without PAS. Statistical analysis revealed an independent association between PAS in KT and KT duration (95% confidence interval (CI): 1.003–1.054, p = 0.029) and serum l-carnitine levels (95% CI: 0.842–0.998, p = 0.044). The area under the receiver operating characteristic curve indicated that the diagnostic power of l-carnitine to predict PAS was 0.789 (95% CI: 0.670–0.881, p < 0.001). Serum-free l-carnitine level is negatively associated with PAS in patients who undergo KT.

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.

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.

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.

Elevated serum osteoprotegerin may predict peripheral arterial disease after kidney transplantation: a single-center prospective cross-sectional study in Taiwan

Background

Osteoprotegerin (OPG) is a potential biomarker for severity and complications of cardiovascular diseases. Peripheral arterial disease (PAD) is associated with an increased risk of death in kidney transplantation (KT) patients. This prospective cross-sectional study evaluated the relationship between serum OPG and PAD in KT patients.

Methods

Seventy-four KT patients were enrolled for this PAD study. Fasting blood samples were obtained to measure serum OPG levels by using enzyme-linked immunosorbent assay kits. The ankle-brachial index (ABI) of less than 0.9 was applied for PAD diagnosis.

Results

Thirteen patients (17.6%) were diagnosed with PAD. Diabetes (P = 0.025), smoking (P = 0.010), and increased OPG levels (P = 0.001) were significantly more frequent in the PAD group. Multivariate logistic regression analysis showed that serum OPG (odds ratio [OR], 1.336; 95% CI [1.108–1.611]; P = 0.002) and diabetes (OR, 7.120; 95% CI [1.080–46.940]; P = 0.041) were independent predictors of PAD in KT patients. The area under the receiver operating characteristic (ROC) curve determined that the probability of a serum OPG level of 7.117 pg/L in predicting PAD in KT patients was 0.799 (95% CI [0.690–0.884]; P < 0.001).

Discussion

Exploration of reliable biomarkers for early identification of vascular risk is crucial for KT patients. Elevated serum OPG levels may predict PAD in KT patients with cutoff value of 7.117 pg/L.

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.

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.

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.

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.

Association Between Serum Leptin Level and Mortality in Kidney Transplant Recipients

OBJECTIVE

Leptin is a hormone made by adipocytes and associated with hypertension, inflammation, and coronary artery disease. Low serum leptin level was associated with higher risk of death in patients with advanced chronic kidney disease. Little is known about the association of serum leptin with outcomes in kidney transplant recipients.

DESIGN

Prospective prevalent cohort.

SETTING AND SUBJECT

We collected sociodemographic and clinical parameters, medical and transplant history, and laboratory data of 979 prevalent kidney transplant recipients. Associations between serum leptin level and death with a functioning graft, all-cause death, and death-censored graft loss over a 6-year follow-up period were examined in survival models.

RESULTS

Serum leptin levels showed moderate negative correlation with eGFR (R = -0.21, P < .001) and positive correlations with BMI (R = 0.48, P < .001) and C-reactive protein (R = 0.20, P < .001). Each 10 ng/mL higher serum leptin level was associated with 7% lower risk of death with functioning graft (hazard ratio [HR] (95% confidence interval [CI]), 0.93 (0.87-0.99)), and this association persisted after adjustment for confounders: HR (95% CI), 0.90 (0.82-0.99). Similar associations were found with all-cause death as outcome. The association between serum leptin level and risk of graft loss was nonlinear, and only low serum leptin level was associated with higher risk of graft loss.

CONCLUSIONS

In prevalent kidney transplant recipients, lower serum leptin was an independent predictor of death.

Association of serum leptin levels with central arterial stiffness in coronary artery disease patients

Background

Serum adipokines have roles in the development of arterial stiffness. Our aim was to investigate the relationship of leptin and the surrogate marker carotid-femoral pulse wave velocity (cfPWV) in coronary artery disease (CAD) patients.

Methods

Fasting blood samples were obtained from 105 CAD patients. 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.

Results

Thirty-seven patients (35.2 %) had high arterial stiffness, and had a higher percentage of diabetes (P = 0.001), hypertension (P = 0.010), older age (P = 0.001), and higher systolic blood pressure (SBP) (P < 0.001), diastolic blood pressure (DBP) (P = 0.021), pulse pressure (P = 0.014), and serum leptin level (P = 0.002) compared to patients with low arterial stiffness. Serum leptin levels correlated with the number of angiographically documented stenotic coronary artery vessels (P < 0.001). After adjusting for factors significantly associated with arterial stiffness, multivariate logistic regression analysis showed that leptin (odds ratio = 1.026, 95 % confidence interval: 1.002–1.051, P = 0.037) was a significant independent predictor of arterial stiffness.

Conclusions

Increasing serum concentration of leptin correlated positively with the total number of stenotic coronary arteries, and serum leptin level may predict the development of arterial stiffness in CAD patients.

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

BACKGROUND

Arterial stiffness could cause adverse outcomes in kidney transplant (KT) patients. Leptin has a role in influencing vascular smooth muscle that may contribute to atherosclerosis. The aim of this study was to evaluate the relationship between fasting serum leptin concentration and carotid-femoral pulse wave velocity (cfPWV) in KT patients.

MATERIALS AND METHODS

Fasting blood samples were obtained from 55 KT patients and 65 subjects from the outpatient department were enrolled as the control group. The cfPWV values of >10 m/s were used to define as the high arterial stiffness group and <10 m/s as the low arterial stiffness group. The predictive ability of leptin for arterial stiffness of KT was assessed using receiver operating characteristic (ROC) curve and multivariate logistic regression analyses.

RESULTS

Kidney transplant patients had lower hemoglobin, but higher blood urea nitrogen, creatinine, total cholesterol, diastolic blood pressure, intact parathyroid hormone levels, and leptin levels than controls. Although cfPWV levels were higher in KT patients, there is no difference of cfPWV levels between KT patients and control (P = .595). Fifteen KT patients (27.3%) were defined in the high arterial stiffness group, and serum leptin level was higher in the high arterial stiffness group compared with the low arterial stiffness group in KT patients (P < .001). Multivariate logistic regression analysis showed that leptin (odds ratio: 1.044, 95% confidence interval [CI]: 1.016-1.072, P = .002) was an independent predictor of arterial stiffness in KT patients. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the ROC curve predicting arterial stiffness in KT patients were 73.33%, 87.5%, 68.7%, 89.7%, and 0.828 (95% CI: 0.703-0.917, P < .001), and the leptin cut-off value was 74.14 ng/mL.

CONCLUSION

Serum fasting leptin level could predict the development of central arterial stiffness of KT patients.

Serum Sclerostin as an Independent Marker of Peripheral Arterial Stiffness in Renal Transplantation Recipients: A Cross-Sectional Study

Wnt/β-catenin signaling pathway is thought to be implicated in the development of arterial stiffness and vascular calcification. As a Wnt signaling pathway inhibitor, it is interesting to investigate whether sclerostin or dickkopf-1 (DKK1) level is correlated with arterial stiffness in renal transplant (RT) recipients. Fasting blood samples were obtained for biochemical data, sclerostin, DKK1, and osteoprotegerin (OPG) determinations. In this study, we applied automatic pulse wave analyzer (VaSera VS-1000) to measure brachial-ankle pulse wave velocity and either sides of brachial-ankle pulse wave velocity value, which greater than 14.0 m/s was determined as high arterial stiffness. Among 68 RT recipients, 30 patients (44.1%) were in the high arterial stiffness group. Compared with patients in the low arterial stiffness group, patients in the high arterial stiffness group had higher prevalence of hypertension (P = 0.002), diabetes (P < 0.001), metabolic syndrome (P = 0.025), longer posttransplant duration (P = 0.005), higher systolic blood pressure (P < 0.001) and diastolic blood pressure (P = 0.018), and higher fasting glucose (P = 0.004), total cholesterol (P = 0.042), blood urea nitrogen (P = 0.020), phosphorus (P = 0.042), and sclerostin levels (P = 0.001). According to our multivariable forward stepwise linear regression analysis, age (β = 0.272, P = 0.014), phosphorus (β = 0.308, P = 0.007), and logarithmically-transformed OPG (log-OPG; β = 0.222, P = 0.046) were positively associated with sclerostin levels, and multivariate logistic regression analysis, sclerostin (odds ratio 1.052, 95% confidence interval 1.007-1.099, P = 0.024), and posttransplant duration (odds ratio 1.024, 95% confidence interval 1.004-1.045, P = 0.019) were the independent predictors of peripheral arterial stiffness in RT recipients. In this study, serum sclerostin level, but not DKK1, was proved to be involved in the pathogenetic process of peripheral arterial stiffness in RT recipients.

Adipocytokines in renal transplant recipients

In the last two decades, perceptions about the role of body fat have changed. Adipocytes modulate endocrine and immune homeostasis by synthesizing hundreds of hormones, known as adipocytokines. Many studies have been investigating the influences and effects of these adipocytokines and suggest that they are modulated by the nutritional and immunologic milieu. Kidney transplant recipients (KTRs) are a unique and relevant population in which the function of adipocytokines can be examined, given their altered nutritional and immune status and subsequent dysregulation of adipocytokine metabolism. In this review, we summarize the recent findings about four specific adipocytokines and their respective roles in KTRs. We decided to evaluate the most widely described adipocytokines, including leptin, adiponectin, visfatin and resistin. Increasing evidence suggests that these adipocytokines may lead to cardiovascular events and metabolic changes in the general population and may also increase mortality and graft loss rate in KTRs. In addition, we present findings on the interrelationship between serum adipocytokine levels and nutritional and immunologic status, and mechanisms by which adipocytokines modulate morbidity and outcomes in KTRs.

Serum adiponectin is a negative predictor of central arterial stiffness in kidney transplant patients

BACKGROUND

The role of adiponectin in arterial stiffness and its relationship to cardiovascular disease is not fully demonstrated and needs further elaboration. In this study, the association between adiponectin level and arterial stiffness is studied among kidney transplant patients.

MATERIAL AND METHODS

Anthropometric data and biochemical data including fasting glucose, lipid profile, renal function and serum adiponectin were determined in 55 kidney transplant patients. Central arterial stiffness was measured and presented by carotid-femoral pulse wave velocity.

RESULTS

Univariate linear analysis showed that body weight, waist circumference, brachial pulse pressure and body mass index were correlated positively with carotid-femoral pulse wave velocity in this patient group. However, logarithmically transformed adiponectin level (log-adiponectin) correlated negatively with carotid-femoral pulse wave velocity. In multivariate regression analysis of factors significantly associated with carotid-femoral pulse wave velocity, it showed that both log-adiponectin (β = -0.427; R(2) = 0.205, p = 0.001) and body weight (β = 0.327; R(2 )=( )0.106, p = 0.007) were independently predictive of central arterial stiffness.

CONCLUSION

Our study suggests that fasting serum adiponectin is negatively associated with carotid-femoral pulse wave velocity, hence arterial stiffness, in kidney transplant patients.

Pathophysiologic and treatment strategies for cardiovascular disease in end-stage renal disease and kidney transplantations

The inextricable link between the heart and the kidneys predestines that significant cardiovascular disease ensues in the face of end-stage renal disease (ESRD). As a point of fact, the leading cause of mortality of patients on dialysis is still from cardiovascular etiologies, albeit differing in particular types of disease from the general population. For example, sudden cardiac death outnumbers coronary artery disease in patients with ESRD, which is the reverse for the general population. In this review, we will focus on the pathophysiology and treatment options of important traditional and nontraditional risk factors for cardiovascular disease in ESRD patients such as hypertension, anemia, vascular calcification, hyperparathyroidism, uremia, and oxidative stress. The evidence of erythropoietin-stimulating agents, phosphate binders, calcimimetics, and dialysis modalities will be presented. We will then discuss how these risk factors may be changed and perhaps exacerbated after renal transplantation. This is largely due to the immunosuppressive agents that are both crucial yet potentially detrimental in the posttransplant state. Calcineurin inhibitors, corticosteroids, and mammalian target of rapamycin inhibitors, the mainstay of transplant immunosuppression, are all known to increase the risks of developing new onset diabetes as well as the metabolic syndrome. Thus, we need to carefully negotiate between patients' cardiovascular profile and their risks of rejection. Finally, we end by considering strategies by which we may minimize cardiovascular disease in the transplant population, as this modality still confers the highest chance of survival in patients with ESRD.

Vascular calcification, bone and mineral metabolism after kidney transplantation

The development of end stage renal failure can be seen as a catastrophic health event and patients with this condition are considered at the highest risk of cardiovascular disease among any other patient groups and risk categories. Although kidney transplantation was hailed as an optimal solution to such devastating disease, many issues related to immune-suppressive drugs soon emerged and it became evident that cardiovascular disease would remain a vexing problem. Progression of chronic kidney disease is accompanied by profound alterations of mineral and bone metabolism that are believed to have an impact on the cardiovascular health of patients with advanced degrees of renal failure. Cardiovascular risk factors remain highly prevalent after kidney transplantation, some immune-suppression drugs worsen the risk profile of graft recipients and the alterations of mineral and bone metabolism seen in end stage renal failure are not completely resolved. Whether this complex situation promotes progression of vascular calcification, a hall-mark of advanced chronic kidney disease, and whether vascular calcifications contribute to the poor cardiovascular outcome of post-transplant patients is reviewed in this article.

Cardiovascular biomarkers in chronic kidney disease: state of current research and clinical applicability

The high incidence of cardiovascular events in chronic kidney disease (CKD) warrants an accurate evaluation of risk aimed at reducing the burden of disease and its consequences. The use of biomarkers to identify patients at high risk has been in use in the general population for several decades and has received mixed reactions in the medical community. Some practitioners have become staunch supporters and users while others doubt the utility of biomarkers and rarely measure them. In CKD patients numerous markers similar to those used in the general population and others more specific to the uremic population have emerged; however their utility for routine clinical application remains to be fully elucidated. The reproducibility and standardization of the serum assays are serious limitations to the broad implementation of these tests. The lack of focused research and validation in randomized trials rather than ad hoc measurement of multiple serum markers in observational studies is also cause for concern related to the clinical applicability of these markers. We review the current literature on biomarkers that may have a relevant role in field of nephrology.