96 research outputs found
Transcriptional regulation of endothelin-1 expression by advanced glycation end-products in human aortic endothelium is mediated via NF-kappaΒ and AP-1
Advanced Glycation End-products (AGEs) are produced by the non-enzymatic glycation of proteins, lipids and nucleic acids, resulting in an overload of highly reactive molecules of endogenous or exogenous (dietary) origin.
Increased AGE levels in circulation and concomitant elevated tissue deposition have been associated with diabetic complications, atheromatosis, ageing and more recently with polycystic ovary syndrome pathogenesis.
Interaction of AGEs with their receptor RAGE (Receptor for AGEs) activates intracellular signaling pathways which induce targeted gene expression in endothelium including upregulation of cell adhesion molecules and endothelin-1 (ET-1), implicated in vascular injury and endothelial dysfunction.
The purpose of this study is to explore the molecular mechanism of AGE-induced regulation of ET-1 gene/protein expression in human endothelial cells and investigate its functional relevance in normal rat vascular endothelium
Insulin resistance in PCOS
Polycystic ovary syndrome (PCOS) is the commonest endocrinopathy
affecting women of reproductive age, manifested with a variety of
clinical signs, none of which is pathognomonic. The association of
insulin resistance and reproductive abnormalities with clinical
hyper-androgenism in a woman was first demonstrated by Achard and Thiers
in the “diabetes of bearded woman.” The link of PCOS with insulin
resistance was subsequently established by clinical studies
characterizing the profound insulin resistance in obese and lean PCOS
patients. Insulin resistance, hyperinsulinemia, and beta-cell
dysfunction are very common in PCOS, but are not required for the
diagnosis. The numerous in vivo and in vitro data supporting the central
role of insulin resistance in the pathogenesis of PCOS found a broad
clinical application in the management of the syndrome, where the
regulation of cycle abnormalities and the facilitation of pregnancy in
obese PCOS patients was assisted by co-administration of agents such as
the well-known insulin sensitizers. The documentation of the presence of
insulin resistance contributed substantially to unravel several
metabolic components present in the syndrome. Today our knowledge about
PCOS appears to have broader health implications and to have profoundly
altered our view of the gravity of this condition
Insulin sensitizers targeting metabolic and reproductive consequences in polycystic ovary syndrome
The central importance of insulin resistance in the pathophysiology of
polycystic ovary syndrome (PCOS) has been established by pioneering and
elegant studies. In addition to the known hormonal and reproductive
abnormalities that characterize this syndrome, metabolic disorders, as
well as morbidities such as the enhanced risk for type 2 diabetes and
increased risk for cardiovascular disease, have also been demonstrated.
Current therapeutic approaches justifiably include insulin-sensitizing
agents promising to comfort women with PCOS. Management with insulin
sensitizers appears to embrace beneficially in a global fashion several
aspects of the syndrome and target most of the associated metabolic and
reproductive consequences
PCOS in adolescents
Polycystic ovary syndrome (PCOS), a heterogeneous syndrome of unknown
aetiology, is the leading cause of anovulation, hirsutism and
infertility in women. This multifactorial syndrome emerges at puberty
and has cardiovascular and metabolic sequelae through menopause. The
common features of normal puberty, namely menstrual irregularities and
insulin resistance, obscure the diagnosis of adolescent PCOS, while
there are no established diagnostic criteria for PCOS in this age group.
The clinical implications of PCOS diagnosis in adolescents remain
unclear. Experts in the field still ponder whether PCOS should be
managed at such a young age with a view to hindering the long-term
sequelae of the syndrome. (C) 2009 Elsevier Ltd. All rights reserved
Targets to treatmetabolic syndrome in polycystic ovary syndrome
Introduction: Metabolic syndrome is comprised of a combination of the
following states: increased insulin resistance, dyslipidemia,
cardiovascular disease, and increased abdominal obesity. Women with
polycystic ovary syndrome (PCOS) have an increased risk of developing
metabolic syndrome over the course of their lives. Metabolic syndrome
increases risk of major cardiovascular events, morbidity, quality of
life, and overall health care costs. Though metabolic syndrome in women
with PCOS is an area of great concern, there is no effective individual
medical therapeutic to adequately treat this issue.
Areas Covered: This article will review key aspects of metabolic
syndrome in PCOS. We will discuss classic and novel therapeutics to
address metabolic syndrome in women with PCOS. We will conclude with the
importance of developing strategic interventions to increase the
compliance to lifestyle and dietary modification, in addition to
appreciation of the emerging pharmaceutical therapeutics available.
Expert Opinion: Innovation in lifestyle modification, including diet,
exercise, with and without dedicated stress reduction techniques is the
future in treatment of metabolic syndrome in PCOS. Application of novel
interventions, such as group medical care, may improve future adherence
to lifestyle modification recommendations, in addition to or in
combination with pharmaceutical therapeutics
The role of genes and environment in the etiology of PCOS
Both genes and the environment contribute to PCOS. Obesity, exacerbated
by poor dietary choices and physical inactivity, worsens PCOS in
susceptible individuals. The role of other environmental modifiers such
as infectious agents or toxins are speculative. Phenotype confusion has
characterized genetic studies of PCOS. Although several loci have been
proposed as PCOS genes including CYP11A, the insulin gene, the
follistatin gene, and a region near the insulin receptor, the evidence
supporting linkage is not overwhelming. The strongest case can be made
for the region near the insulin receptor gene (but not involving this
gene), as it has been identified in two separate studies, and perhaps
most importantly has not yet been refuted by larger studies. However,
the responsible gene at chromosome 19p13.3 remains to be identified. To
date, no gene has been identified that causes or contributes
substantially to the development of a PCOS phenotype
Aging ovary and the role for advanced glycation end products
Objective: The hypothalamic gonadotropin-releasing hormone pulse
generator, the pituitary gonadotropes, the ovaries, and the uterus play
a crucial role in female fertility. A decline in reproductive
performance represents a complex interplay of actions at all levels of
the hypothalamic-pituitary-ovarian axis. Recently, in the field of
female reproductive aging attention is drawn to the carbonyl stress
theory. Advanced glycation end products (AGEs) contribute directly to
protein damage, induce a chain of oxidative stress (OS) reactions, and
increase inflammatory reactions. Here, we highlight some of the
mechanisms underlying glycation damage in the ovary.
Methods: Searches of electronic databases were performed. Articles
relevant to possible role of OS, AGEs, and receptor for AGE (RAGE) in
aging ovary were summarized in this interpretive literature review.
Results: Follicular microenvironment undergoes an increase in OS with
aging. Data support the role of OS in ovulatory dysfunction because AGEs
are well-recognized mediators of increased OS. RAGE and AGE-modified
proteins with activated nuclear factor-kappa B are expressed in human
ovarian tissue. It was suggested that accumulation of AGEs products at
the level of the ovarian follicle might trigger early ovarian aging or
could be responsible for reduced glucose uptake by granulosa cells,
potentially altering follicular growth. Moreover, impaired methylglyoxal
detoxification causing relevant damage to the ovarian proteome might be
one of the mechanisms underlying reproductive aging.
Conclusions: Further investigation of the role for the AGE-RAGE axis in
the ovarian follicular environment is needed, and results could relate
to assisted reproduction technology outcomes and new measures of ovarian
reserve
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