Impact of androgen and dietary advanced glycation end products on female rat liver

Diet-Derived Advanced Glycation End Products (dAGEs) Induce Proinflammatory Cytokine Expression in Cardiac and Renal Tissues of Experimental Mice: Protective Effect of Curcumin

The beneficial effect of curcumin (CU) on dietary AGEs (dAGEs) involves blocking the overexpression of proinflammatory cytokine genes in the heart and kidney tissues of experimental mice. The animals were divided into six groups (n = 6/group) and were fed a heat-exposed diet (dAGEs) with or without CU for 6 months. Their blood pressure (BP) was monitored by a computerized tail-cuff BP-monitoring system. The mRNA and protein expression levels of proinflammatory genes were analyzed by RT-PCR and western blot, respectively. A marked increase in BP (108 ± 12 mmHg vs 149 ± 15 mmHg) accompanied by a marked increase in the heart and kidney weight ratio was noted in the dAGE-fed mice. Furthermore, the plasma levels of proinflammatory molecules (C5a, ICAM-1, IL-6, MCP-1, IL-1β and TNF-α) were found to be elevated (3-fold) in dAGE-fed mice. mRNA expression analysis revealed a significant increase in the expression levels of inflammatory markers (Cox-2, iNOS, and NF-κB) (3-fold) in cardiac and renal tissues of dAGE-fed mice. Moreover, increased expression of RAGE and downregulation of AGER-1 (p < 0.001) were noticed in the heart and kidney tissues of dAGE-fed mice. Interestingly, the dAGE-induced proinflammatory genes and inflammatory responses were neutralized upon cotreatment with CU. The present study demonstrates that dietary supplementation with CU has the ability to neutralize dAGE-induced adverse effects and alleviate proinflammatory gene expression in the heart and kidney tissues of experimental mice.

High Plasmatic Levels of Advanced Glycation End Products are Associated with Metabolic Alterations and Insulin Resistance in Preeclamptic Women

Aims:

The purpose of this study was to investigate the association between plasmatic levels of advanced end glycation products (AGEs) and the metabolic profile in subjects diagnosed with preeclampsia, due to the known relation of these molecules with oxidative stress and inflammation, which in turn are related with PE pathogenesis.

Background:

It has been reported that increased levels of AGEs are observed in patients with preeclampsia as compared with healthy pregnant subjects, which was mainly associated with oxidative stress and inflammation. Besides, in women with preeclampsia, there are metabolic changes such as hyperinsulinemia, glucose intolerance, dyslipidemia, among others, that are associated with an exacerbated insulin resistance. Additionally, some parameters indicate the alteration of hepatic function, such as increased levels of liver enzymes. However, the relationship of levels of AGEs with altered lipidic, hepatic, and glucose metabolism parameters in preeclampsia has not been evaluated.

Objective:

To investigate the association between plasmatic levels of AGEs and hepatic, lipid, and metabolic profiles in women diagnosed with preeclampsia.

Methods:

Plasma levels of AGEs were determined by a competitive enzyme-linked immunosorbent assay (ELISA) in 15 patients diagnosed with preeclampsia and 28 normoevolutive pregnant subjects (control group). Hepatic (serum creatinine, gammaglutamyl transpeptidase, aspartate transaminase, alanine transaminase, uric acid, and lactate dehydrogenase), lipid (apolipoprotein A, apolipoprotein B, total cholesterol, triglycerides, low-density lipoproteins, and high-density lipoproteins), and metabolic variables (glucose, insulin, and insulin resistance) were assessed.

Results:

Plasmatic levels of AGEs were significantly higher in patients with preeclampsia as compared with the control. A positive correlation between circulating levels of AGEs and gamma-glutamyl transpeptidase, uric acid, glucose, insulin, and HOMA-IR levels was found in patients with preeclampsia. In conclusion, circulating levels of AGEs were higher in patients with preeclampsia than those observed in healthy pregnant subjects. Besides, variables of hepatic and metabolic profile, particularly those related to insulin resistance, were higher in preeclampsia as compared with healthy pregnant subjects. Interestingly, there is a positive correlation between AGEs levels and insulin resistance.

Conclusions:

Circulating levels of AGEs were higher in patients with preeclampsia than those observed in healthy pregnant subjects. Besides, hepatic and metabolic profiles, particularly those related to insulin resistance, were higher in preeclampsia as compared with healthy pregnant subjects. Interestingly, there is a positive correlation between AGEs levels and insulin resistance, suggesting that excessive glycation and an impaired metabolic profile contribute to the physiopathology of preeclampsia.

How to choose the suitable animal model of polycystic ovary syndrome?

Polycystic ovary syndrome (PCOS) is a gynecological metabolic and endocrine disorder with uncertain etiology. To understand the etiology of PCOS or the evaluation of various therapeutic agents, different animal models have been introduced. Considering this fact that is difficult to develop an animal model that mimics all aspects of this syndrome, but, similarity of biological, anatomical, and/or biochemical features of animal model to the human PCOS phenotypes can increase its application. This review paper evaluates the recently researched animal models and introduced the best models for different research purposes in PCOS studies. During January 2013 to January 2017, 162 studies were identified which applied various kinds of animal models of PCOS including rodent, primate, ruminant and fish. Between these models, prenatal and pre-pubertal androgen rat models and then prenatal androgen mouse model have been studied in detail than others. The comparison of main features of these models with women PCOS demonstrates higher similarity of these three models to human conditions. Thereafter, letrozole models can be recommended for the investigation of various aspects of PCOS. Interestingly, similarity of PCOS features of post-pubertal insulin and human chorionic gonadotropin rat models with women PCOS were considerable which can make it as a good choice for future investigations.

MECHANISMS IN ENDOCRINOLOGY: The sexually dimorphic role of androgens in human metabolic disease

Female androgen excess and male androgen deficiency manifest with an overlapping adverse metabolic phenotype, including abdominal obesity, insulin resistance, type 2 diabetes mellitus, non-alcoholic fatty liver disease and an increased risk of cardiovascular disease. Here, we review the impact of androgens on metabolic target tissues in an attempt to unravel the complex mechanistic links with metabolic dysfunction; we also evaluate clinical studies examining the associations between metabolic disease and disorders of androgen metabolism in men and women. We conceptualise that an equilibrium between androgen effects on adipose tissue and skeletal muscle underpins the metabolic phenotype observed in female androgen excess and male androgen deficiency. Androgens induce adipose tissue dysfunction, with effects on lipid metabolism, insulin resistance and fat mass expansion, while anabolic effects on skeletal muscle may confer metabolic benefits. We hypothesise that serum androgen concentrations observed in female androgen excess and male hypogonadism are metabolically disadvantageous, promoting adipose and liver lipid accumulation, central fat mass expansion and insulin resistance.