Metabolic hormones are integral regulators of female reproductive health and function

The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.

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.

Cardiovascular Adiponectin Resistance: The Critical Role of Adiponectin Receptor Modification

For the past two decades, a great deal of research has been published concerning adiponectin (APN), an abundant protein responsible for regulating numerous biologic functions including antioxidative, antinitrative, anti-inflammatory, and cardioprotective effects. A review of APN and its two major receptors is timely because of new findings concerning the mechanisms by which APN signaling may be altered in pathologic processes such as diabetes and heart failure. In this review we elaborate on currently known information regarding the physiologic role of APN and the known mechanisms underlying pathologic APN resistance - namely, APN receptor downregulation and phosphorylation - and provide insight regarding the future directions of APN research including an assessment of the clinical applicability of preventing pathologic post-translational modification of the APN receptor.

Adiponectin predicts cardiovascular events in diabetes dialysis patients

OBJECTIVES

Adiponectin is an insulin-sensitizing, anti-inflammatory adipokine with anti-atherogenic actions in the general population. In dialysis patients it is unclear whether adiponectin conserves its protective value or is, on the contrary, associated to worse prognosis. We assessed the predictive value of adiponectin for atherosclerosis related cardiovascular events in type 2 diabetic dialysis patients.

DESIGN AND METHODS

Prevalent diabetic dialysis patients from three dialysis units (n=77) were enrolled in a 3years' prospective observational study. Serum adiponectin, clinical and laboratory parameters were determined at baseline; new occurrence of atherosclerosis related events (coronary events, atherosclerosis obliterans, and stroke) was recorded.

RESULTS

Baseline adiponectin was 17.25(9.53-31.97) μg/mL and significantly correlated to HDL cholesterol (r=0.29, p=0.01), triglycerides (r=-0.40, p=0.0004), ferritin (r=-0.29, p=0.02), transferrin (r=-0.28, p=0.02), and uric acid (r=-0.24, p=0.04). In multivariate analysis association to triglycerides (p=0.001), HDL cholesterol (p=0.01) and ferritin (p=0.04) remained significant. 36 new fatal and non-fatal new cardiovascular events occurred, 29 patient died. Cox proportional regression analysis showed that adiponectin below or above a ROC-derived cut-off of 27.33μg/mL significantly influenced event-free survival: hazard ratio (HR) 2.48, 95% confidence interval (CI) (1.09-5.66), p=0.031 along with fasting glucose HR 1.01, 95%CI(1.00-1.02), p=0.01 and history of cardiovascular events at inclusion HR 3.16, 95%CI(1.36-7.32), p=0.007. In multivariate analysis baseline adiponectin HR 5.02, 95%CI(0.98-25.06), p=0.05 and glycemia HR 1.01, 95%CI(1.00-1.02), p=0.01 influenced event-free survival. Adiponectin also predicted cardiovascular events in patients without cardiovascular disease at inclusion but was not associated to overall mortality.

CONCLUSIONS

In diabetes dialysis patients low adiponectin favors occurrence of atherosclerosis related cardiovascular events.

Clinical use of adiponectin as a marker of metabolic dysregulation

Adiponectin concentrations exhibit strong cross-sectional relationships with obesity, inflammation, and diabetes. Adiponectin concentrations have been extensively evaluated as epidemiologic markers of diabetes and cardiovascular disease risk. In the present review we will provide an overview of these epidemiologic relationships as the backdrop for an evaluation of the clinical applications of adiponectin measurements. These include using adiponectin as an indicator of need for preventive or therapeutic intervention, as a predictor of response to therapy, and as a marker of therapeutic effectiveness. These efforts are laying the groundwork for the transition of adiponectin measurements from the laboratory to the clinic.

Is there an association between elevated or low serum levels of phosphorus, parathyroid hormone, and calcium and mortality in patients with end stage renal disease? A meta-analysis

BACKGROUND

Biochemical markers of altered mineral metabolism have been associated with increased mortality in end stage renal disease patients. Several studies have demonstrated non-linear (U-shaped or J-shaped) associations between these minerals and mortality, though many researchers have assumed linear relationships in their statistical modeling. This analysis synthesizes the non-linear relationships across studies.

METHODS

We updated a prior systematic review through 2010. Studies included adults receiving dialysis and reported categorical data for calcium, phosphorus, and/or parathyroid hormone (PTH) together with all-cause mortality. We performed 2 separate meta-analyses to compare higher-than-referent levels vs referent and lower-than-referent levels vs referent levels.

RESULTS

A literature review showed that when a linear relationship between the minerals and mortality was assumed, the estimated associations were more likely to be smaller or non-significant compared to non-linear models. In the meta-analyses, higher-than-referent levels of phosphorus (4 studies, RR = 1.20, 95% CI = 1.15-1.25), calcium (3 studies, RR = 1.10, 95% CI = 1.05-1.14), and PTH (5 studies, RR = 1.11, 95% CI = 1.07-1.16) were significantly associated with increased mortality. Although no significant associations between relatively low phosphorus or PTH and mortality were observed, a protective effect was observed for lower-than-referent calcium (RR = 0.86, 95% CI = 0.83-0.89).

CONCLUSIONS

Higher-than-referent levels of PTH, calcium, and phosphorus in dialysis patients were associated with increased mortality risk in a selection of observational studies suitable for meta-analysis of non-linear relationships. Findings were less consistent for lower-than-referent values. Future analyses should incorporate the non-linear relationships between the minerals and mortality to obtain accurate effect estimates.

Adiponectin in renal disease--a review of the evidence as a risk factor for cardiovascular and all-cause mortality

Adiponectin, an adipokine, was discovered in 1995. The initial evidence led to the study of adiponectin as a determinant of insulin sensitivity and blood glucose levels. The literature then evolved to reports of the inverse association of adiponectin with incident Type 2 diabetes mellitus and coronary heart disease. Shortly thereafter, reports of a positive association with heart failure and mortality appeared and were replicated. We review here the basic science evidence and clinical studies of the role of renal function and kidney disease as a determinant of adiponectin.

Anti-inflammatory and anti-atherogenic properties of adiponectin

Obesity-related disorders, such as insulin resistance, hypertension and atherosclerosis, are associated with chronic inflammation. Adiponectin is an adipocyte-derived secreted factor that is down-regulated in obese states. Adiponectin exerts the protective actions on obesity-linked diseases, such as insulin resistance and atherosclerosis by attenuating chronic inflammation in its target organs. Adiponectin also exerts the salutary effects on vascular disorders by directly acting on vascular component cells including endothelial cells, smooth muscle cells and macrophages. This review will focus on the role of adiponectin in control of inflammatory responses and atherogenic processes.

Is adiponectin a marker of preclinical atherosclerosis in kidney transplantation?

The aim of this study was to analyze the relationship between pre-transplant adiponectin (pre-ADP), abnormalities in glucose homeostasis (AGH) at three months post-transplantation, and preclinical atherosclerosis in non-diabetic patients prior to kidney transplantation (KT).

METHODS

We carried out a multicenter study in 157 non-diabetic KT patients (66.5% men; age: 50±13 yr). Pre-ADP levels were analyzed using radioimmunoassay. Carotid ultrasound was performed to determine carotid intima-media thickness (c-IMT). Oral glucose tolerance test was carried out to classify patients according ADA criteria.

RESULTS

Of the patients, 52.8% had AGH. Median pre-ADP was 19.5 (14-27) μg/mL. An inverse correlation was found between ADP and HOMA index (r=-0.432; p<0.001). Median c-IMT was 0.6 (0.48-0.71) mm. Significant inverse correlation existed between ADP and c-IMT on both sides (p<0.05). Patients with c-IMT >0.6 mm had more AGH (p=0.012) and lower ADP levels (p=0.02). We performed a logistic regression analysis using preclinical atherosclerosis (c-IMT ≥0.6 mm) as dependent variable and sex, age, BMI, ADP, AGH, and HOMA index as independent variables of altered c-IMT. Age, pre-ADP, and AGH were independent risk factors for elevated c-IMT.

CONCLUSIONS

Patients with AGH have a greater presence of preclinical atherosclerosis. ADP has an inverse relationship with AGH and is an independent marker of preclinical atherosclerosis.

Waist circumference modifies the relationship between the adipose tissue cytokines leptin and adiponectin and all-cause and cardiovascular mortality in haemodialysis patients

BACKGROUND

the relationships between the adipose tissue cytokines leptin and adiponectin (ADPN) and clinical outcomes have not been well studied in haemodialysis (HD) patients and remain highly controversial. As central obesity is an important modifier of the effect of various risk factors for clinical outcomes, we tested the hypothesis that waist circumference (WC) modifies the link between these cytokines and both overall and cardiovascular death in HD patients.

METHODS

a total of 537 HD patients participated in a prospective cohort study.

RESULTS

leptin and ADPN were inversely related to each other and robustly associated with WC (P < 0.001). During follow-up (average 29 months, range 1-47 months) 182 patients died, including 115 from cardiovascular causes. In analyses adjusting for potential confounders, there were strong interactions between leptin and WC in relationship to both all-cause (P < 0.001) and cardiovascular death (P = 0.002). Accordingly, a fixed excess of leptin signalled a gradually increasing risk for all-cause and cardiovascular mortality in patients with a large WC but an opposite effect in those with a relatively small WC. An interaction between ADPN and WC for all-cause (P = 0.01) and cardiovascular mortality (P = 0.01) emerged only in models excluding the leptin-WC interaction, suggesting that these adipokines share a common pathway leading to adverse clinical events in HD patients.

CONCLUSIONS

the predictive value of leptin and ADPN for all-cause and cardiovascular death in HD patients appears to be critically dependent on WC. These findings support the hypothesis that disturbances in adipokine levels are involved in adverse clinical outcomes in HD patients with abdominal obesity.