Visceral Adipose Tissue and Leptin Hyperproduction Are Associated With Hypogonadism in Men With Chronic Kidney Disease

Leptin Is Associated with Testosterone, Nutritional Markers, and Vascular Muscular Dysfunction in Chronic Kidney Disease

Chronic kidney disease (CKD) causes specific hormonal disturbances, such as variations in leptin and testosterone levels and function. These disturbances can promote errors in signaling interaction and cellular information processing and can be implicated in the pathogenesis of atherosclerosis. This study investigates the factors that affect leptin in CKD patients and examines how leptin is related to markers of vascular disease. We conducted a cross-sectional study of 162 patients with CKD in pre-dialysis and dialysis stages. We recorded clinical and laboratory data, including leptin, testosterone, and subclinical atherosclerosis markers like brachial-ankle pulse wave velocity (ba PWV) in pre-dialysis CKD patients and flow-mediated vasodilation (FMD) and nitroglycerin-mediated vasodilation (NMD) in hemodialysis (HD) patients. Leptin was significantly correlated with testosterone in CKD pre-dialysis stages (p < 0.001) and also in HD (p = 0.026), with adipose tissue mass in pre-dialysis stages (p < 0.001), and also in HD (p < 0.001). In women HD patients, leptin correlated with NMD (p = 0.039; r = -0.379); in all HD patients, leptin correlated with C reactive protein (p = 0.007; r = 0.28) and parathormone (p = 0.039; r = -0.220). Our research emphasizes the connection between leptin, adipose tissue, and testosterone in all stages of CKD. Leptin was associated with NMD in HD women and correlated with inflammatory syndrome and parathyroid hormone in all HD patients.

Association between visceral adipose tissue and total testosterone among the United States male adults: a cross-sectional study

Visceral adipose tissue (VAT) is regarded as an important risk factor for obesity-related diseases. The results of the association between VAT and total testosterone (TT) are controversial and whether this association is nonlinear is still unknown. 3971 male participants who were aged 20-59 years from the National Health and Nutrition Examination Surveys 2011-2016 were included. VAT area was measured by dual-energy x-ray absorptiometry. TT in serum was assessed utilizing the isotope dilution liquid chromatography-tandem mass spectrometry technique. Linear regression models assessed the associations between VAT area and TT. A restricted cubic spline model was employed to investigate nonlinear relationships. A two-piecewise linear regression model was applied to determine the threshold effect. Subgroup analyses were conducted. The weighted methods were utilized in all analyses. VAT area was inversely associated with TT in the crude and adjusted models. In the fully adjusted model, VAT area was associated with TT (β = -0.59, 95% confidence interval [CI] = -0.74, -0.43) and compared to the first tertile of VAT area, the second and the third tertile had a lower TT level, the β and 95% CI = -65.49 (-83.72, -47.25) and -97.57 (-121.86, -73.27) respectively. We found these inverse associations were nonlinear. The cutoff point of the VAT area was 126 cm2. When the VAT area was <126 cm2, VAT area was significantly associated with a lower TT level (β = -1.55, 95% CI = -1.93 to -1.17, p < 0.0001). However, when the VAT area was ≥126 cm2, this association was less apparent (β = -0.26, 95% CI = -0.52 to 0.01, p = 0.06). No significant interactions among different ages (<50 or ≥50 years), marital, and physical activity status were found. These findings underscore the potential for VAT area as a modifiable indicator for improving testosterone deficiency.

Testosterone Deficiency and Nutritional Parameters as Predictors of All-Cause Mortality among Male Dialysis Patients

Background: Chronic kidney disease (CKD) is associated with an accelerated risk of cardiovascular mortality. Hormonal and metabolic disorders in CKD may constitute novel risk factors. Our objective was to characterize and evaluate prognostic implications of circulating sex steroids and selected nutritional parameters in patients at different stages of CKD. Methods: Studied groups were composed of 78 men: 31 on hemodialysis (HD), 17 on peritoneal dialysis (PD), 30 with CKD stage G3-G4. Total testosterone (TT), dehydroepiandrosterone sulphate (DHEA-S), androstenedione, luteinizing hormone (LH), prolactin (PRL), and biochemical parameters were measured; Free testosterone (FT) was calculated. Results: The lowest TT and FT were observed in HD, the highest- in CKD (p = 0.006 for TT, p = 0.005 for FT). TT positively correlated with total cholesterol in HD (p = 0.012), FT negatively correlated with BMI in CKD (p = 0.023). During the 12 months, 9 patients died (5 in the HD, 4 in the PD group). The deceased group had significantly lower concentrations of albumin (p = 0.006) and prealbumin (p = 0.001), and a significantly higher concentration of androstenedione (p = 0.019) than the surviving group. In the group of men on dialysis, a serum TT concentration <2.55 ng/mL (Q1-first quartile) was associated with a 3.7-fold higher risk of death, although statistical significance was not achieved (p = 0.198). After analysis of the ROC curves, the FT level was the best prognostic marker in HD (AUC = 0.788; 95% CI: 0.581−0.996; p = 0.006) Conclusions: Total and free testosterone levels were lower in the HD group than in the CKD group. The nutritional status undoubtedly affects the survival of dialysis patients but also the concentrations of testosterone significantly contributes to further worsening the prognosis.

Histologically proven hepatic steatosis associates with lower testosterone levels in men with obesity

Men with obesity often present with low testosterone (T) and sex hormone-binding globulin (SHBG) levels. Several mechanisms for this have been proposed, but as SHBG is secreted by hepatocytes and sex steroids undergo hepatic metabolization, this study investigates whether severity and histological components of nonalcoholic fatty liver disease (NAFLD) are associated with sex steroid levels in obese men. This cross-sectional study included 80 obese men (age: 46 ± 11 years; body mass index: 42.2 ± 5.5 kg m⁻²). Serum levels of total T and estradiol (E₂) were measured using liquid chromatography coupled with tandem mass spectroscopy (LC/MS-MS) and SHBG and gonadotropins by immunoassay. Liver biopsies were evaluated using Steatosis, Activity, and Fibrosis scoring. Participants with steatohepatitis had similar median (1^st quartile–3^rd quartile) total T levels (7.6 [5.0–11.0] nmol l⁻¹ vs 8.2 [7.2–10.9] nmol l⁻¹; P = 0.147), lower calculated free T (cFT) levels (148.9 [122.9–188.8] pmol l⁻¹ vs 199.5 [157.3–237.6] pmol l⁻¹; P = 0.006), and higher free E₂/T ratios (10.0 [6.4–13.9] x10^-3 vs 7.1 [5.7–10.7] x10^-3; P = 0.026) compared to men with only nonalcoholic fatty liver. Among the histological components of NAFLD, only steatosis was independently associated with total T (r_s = −0.331, P = 0.003) and cFT levels (r_s = −0.255, P = 0.025). Obese men with steatohepatitis have even lower cFT levels compared to those without, an association mainly driven by grade of steatosis. Whether this reflects a subgroup of men with a more severe obesity-related phenotype or results from direct relations between hepatic steatosis and sex steroid metabolism needs further investigation.

Metabolism of testosterone during weight loss in men with obesity

OBJECTIVE

Men with obesity often have low total and, with increasing adiposity, also low free testosterone (T) levels, which can partially restore during weight loss. Although this is partly explained by lower sex hormone binding globulin (SHBG) production and hypothalamic-pituitary downregulation, it is still not unravelled whether changes in androgen metabolism contribute to this phenomenon. Therefore, early changes in urinary excretion of T and its metabolites, during weight loss, in men with obesity are investigated.

DESIGN

Longitudinal study.

METHODS

Fourteen men with obesity (age 52(45-60)years, BMI 42.6(41.8-44.8)kg/m²) underwent gastric bypass surgery (GBS). Before surgery and 3 weeks, 6 weeks, 6 months and 1 year thereafter, 24 h urine and fasting serum samples were collected. Serum T and estradiol (E₂) levels were analyzed using LC-MS/MS and urinary metabolites of T with GC-MS/MS.

RESULTS

Already three weeks after GBS, serum SHBG and total T levels increased and remained increased as compared to baseline (all,p < 0.0125). Gonadotropins and (free) E₂ levels were unchanged, serum E₂/T ratio decreased (p < 0.0125). Total amount of urinary T increased non-significantly with mean increases of 53 % one year after GBS (p = 0.026). Urinary E₂/T, estrone/T, 3α-androstanediol/T and androsterone/T ratios decreased after GBS (p < 0.0125).

CONCLUSIONS

Restoration of circulating T levels during weight loss in this population is not only brought about by normalization of circulating SHBG levels, but increased production of and alterations in T metabolism also contribute. More specifically, relative decreases in aromatization and lower 5α-reductase activity might also be involved in restoring T levels in men with obesity.

Advanced Chronic Kidney Disease is a Strong Predictor of Hypogonadism and is Associated with Decreased Lean Tissue Mass

Purpose

In patients with chronic kidney disease (CKD), hypogonadism is more frequent than in the general population and its prevalence ranges between 40% and 60%. The aim of the study was to investigate the prevalence of hypogonadism and its association with kidney function, body composition, inflammatory markers and lipid disorders in patients with CKD.

Materials and Methods

The study population consisted of 112 men aged ≥40 years in different stages of CKD: 33 participants with eGFR ≥60 mL/min/1.73 m², 27 men with eGFR 30–59 mL/min/1.73 m², 17 predialysis patients with eGFR <30 mL/min/1.73 m², and 35 men on hemodialysis therapy three times a week for more than 3 months (G5D stage). Total testosterone (TT) levels were measured and free testosterone (FT) levels were calculated. Body composition was assessed using bioimpedance spectroscopy (Body Composition Monitor, FMC). Statistical analysis was performed using Statistica version 13.1.

Results

CKD stage was a strong predictor of hypogonadism (providing an information value of 0.83). The weight of evidence technique allowed us to differentiate the high-risk group, which was a group of patients with advanced CKD, defined as eGFR <30 mL/min/1.73 m². In this group, the likelihood of hypogonadism was 69.23%. Another significant predictor of hypogonadism was lean tissue index (LTI). TT and FT levels were significantly lower in the advanced CKD group in comparison to the control group, whereas prolactin, luteinizing hormone and C-reactive protein levels were significantly higher in the advanced CKD group. The LTI was significantly lower in advanced CKD and was positively correlated with TT and FT.

Conclusion

Decreased eGFR and decreased LTI are predictors of hypogonadism associated with CKD. The study results suggest that hypogonadism screening should be carried out when eGFR deceases below 30 mL/min/1.73 m².

Lipid accumulation product and late-onset hypogonadism in middle-aged and elderly men: results from a cross-sectional study in China

OBJECTIVES

Hypogonadism in men is related to the deterioration of general health. However, the association between lipid overaccumulation and ageing-related hypogonadism remains an undetermined concept. We aimed to provide an insight into the possible links between the lipid accumulation product (LAP) and late-onset hypogonadism (LOH).

SETTING

Sun Yat-sen Memorial Hospital of Sun Yat-sen University.

PARTICIPANTS

We included a population sample of 997 subjects aged 40 years or older.

PRIMARY AND SECONDARY OUTCOME MEASURES

The LAP was calculated by gender-specific equations using waist circumference (WC) and triglyceride (TG). LOH was defined by the presence of androgen deficiency symptoms and low serum total testosterone levels.

RESULTS

The prevalence of LOH was 9.4% in this population and gradually increased according to increasing LAP quartiles. Compared with subjects without LOH, ageing men with LOH had higher body mass index, WC, systolic blood pressure, percentage of subjects currently smoking, TG and follicle stimulating hormone and lower low-density lipoprotein cholesterol and sex hormone binding globulin. In multivariate logistic regression analysis, the adjusted ORs of LOH for increasing LAP quartiles 1-4 were 1.00 (reference), 1.10 (95% CI 0.45-2.69), 2.15 (95% CI 0.93-4.94) and 3.83 (95% CI 1.73-8.45), respectively.

CONCLUSION

Body lipid accumulation evaluated by the LAP is independently associated with the prevalence of LOH in middle-aged and elderly Chinese men.

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.

Leptin and chronic kidney diseases

Chronic kidney diseases (CKD), a common outcome of various kidney diseases, cause a series of refractory complications, which lead to great economic burdens on patients. The clinical outcomes of CKD depend on various factors, including metabolic disorders. Leptin, a peptide hormone, produced in adipose tissues, plays an important role in regulating food consumption and energy expenditure. Leptin also influences the immune system and hematopoiesis. Increased leptin status is observed in CKD, leptin deficiency attenuates the immune response in nephritis. Conversely, leptin inhibits the development of obesity, which is closely associated glomerular disorder. Now, the precise role of leptin in CKD remains elusive. This review will give an integrated understanding of the potential role of leptin and its interactions with other signal molecules in CKD.