Metformin is the most commonly used treatment to increase insulin sensitivity in insulin-resistant (IR) conditions such as diabetes, prediabetes, polycystic ovary syndrome, and obesity. There is a ...well-documented correlation between glucose transporter 4 (GLUT4) expression and the level of IR. Therefore, the observed increase in peripheral glucose utilization after metformin treatment most likely comes from the induction of GLUT4 expression and its increased translocation to the plasma membrane. However, the mechanisms behind this effect and the critical metformin targets are still largely undefined. The present review explores the evidence for the crucial role of changes in the expression and activation of insulin signaling pathway mediators, AMPK, several GLUT4 translocation mediators, and the effect of posttranscriptional modifications based on previously published preclinical and clinical models of metformin's mode of action in animal and human studies. Our aim is to provide a comprehensive review of the studies in this field in order to shed some light on the complex interactions between metformin action, GLUT4 expression, GLUT4 translocation, and the observed increase in peripheral insulin sensitivity.
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Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder in women of reproductive age. Its heterogeneous clinical presentation is characterized by hyperandrogenemia, ...reproductive changes, polycystic ovary morphology, and insulin resistance (IR). The primary pathophysiological process in its multifactorial etiology has not yet been identified. However, the two most proposed core etiologies are the disruption of insulin metabolism and hyperandrogenemia, both of which begin to intertwine and propagate each other in the later stages of the disease. Insulin metabolism can be viewed as the interconnectedness of beta cell function, IR or insulin sensitivity, and insulin clearance. Previous studies of insulin metabolism in PCOS patients have yielded conflicting results, and literature reviews have focused mainly on the molecular mechanisms and clinical implications of IR. In this narrative review, we comprehensively explored the role of insulin secretion, clearance, and decreased sensitivity in target cells as a potential primary insult in PCOS pathogenesis, along with the molecular mechanism behind IR in PCOS.
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Obesity, primarily characterized by excessive fat accumulation, is a multifactorial chronic disease with an increasing global prevalence. Despite the well-documented epidemiology and significant ...advances in understanding its pathophysiology and clinical implications, the impact of sex is typically overlooked in obesity research. Worldwide, women have a higher likelihood to become obese compared to men. Although women are offered weight loss interventions more often and at earlier stages than men, they are more vulnerable to psychopathology. Men, on the other hand, are less likely to pursue weight loss intervention and are more susceptible to the metabolic implications of obesity. In this narrative review, we comprehensively explored sex- and gender-specific differences in the development of obesity, focusing on a variety of biological variables, such as body composition, fat distribution and energy partitioning, the impact of sex steroid hormones and gut microbiota diversity, chromosomal and genetic variables, and behavioural and sociocultural variables influencing obesity development in men and women. Sex differences in obesity-related comorbidities and varying effectiveness of different weight loss interventions are also extensively discussed.
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Adipose tissue can be divided into white adipose tissue (WAT), brown adipose tissue (BAT), and beige adipose tissue, according to the differences in morphology. WAT acts as a buffer for increased ...energy intake and decreased energy expenditure during the development of obesity, resulting in visceral and ectopic WAT accumulation. These WAT depots are strongly associated with chronic systemic inflammation, insulin resistance, and cardiometabolic risk related to obesity. They represent a primary weight loss target in anti-obesity management. Second-generation anti-obesity medications glucagon-like peptide-1 receptor agonists (GLP-1RAs) cause weight loss and improve body composition by reducing visceral and ectopic fat depots of WAT, resulting in improved cardiometabolic health. Recently, the understanding of the physiological significance of BAT beyond its primary function in generating heat through non-shivering thermogenesis has been expanded. This has raised scientific and pharmaceutical interest in the manipulation of BAT to further enhance weight reduction and body weight maintenance. This narrative review focuses on the potential impact of GLP-1 receptor agonism on BAT, particularly in human clinical studies. It provides an overview of the role of BAT in weight management and highlights the need for further research to elucidate the mechanisms by which GLP-1RAs affect energy metabolism and weight loss. Despite encouraging preclinical data, limited clinical evidence supports the notion that GLP-1RAs contribute to BAT activation.
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Despite the continuous effort to understand the pathophysiology and determine potential therapeutic targets, PCOS treatment largely depends on lifestyle intervention and symptomatic management of ...individual signs and symptoms. International guidelines recognize the importance of weight reduction as a cornerstone for the achievement of better metabolic, reproductive, and cardiovascular outcomes in PCOS women who are overweight or obese. With its profound weight loss potential in patients with or without diabetes, the administration of GLP-1 receptor agonists has been investigated in overweight/obese women with PCOS in several single-center randomized control trials with considerable variation in the dosing regimen, follow-up duration, and outcome measurements over recent years. Most trials reported superior weight loss effects of GLP-1 receptor agonists compared to lifestyle changes or metformin, with additional metabolic, reproductive, and cardiovascular benefits in this population. However, their use is currently not widely accepted by the clinical community that treats this population. The major concern is how to balance the reproductive and metabolic treatment strategies since the use of GLP-1 receptor agonists requires effective contraception while on therapy and a washout period before pregnancy. Both approaches are not mutually exclusive, yet the best choice requires a careful assessment of the clinical context. Knowing a patient’s individual circumstances, precise clinical sub-phenotyping, and regular monitoring are crucial components for the safe and effective use of these new tools. In the present narrative review, we explore the current clinical evidence and provide the future perspectives and challenges for their implementation in PCOS management.
Polycystic ovary syndrome (PCOS) manifests a multifactorial pathology characterized by polycystic ovaries, menstrual cycle disorders, varying degrees of hyperandrogenism, and an ad-verse metabolic ...risk profile. The position of hyperandrogenism in this syndrome has been extensively studied. A multitude of mechanisms place it in the position of cause but also of consequence; therefore, ongoing research efforts are focused on identifying medications that can effectively reduce levels of androgens in women with PCOS. Moreover, lipid abnormalities are common in this population, with up to 70% of patients having dyslipidemia. Statins may have potential therapeutic benefits for women with PCOS, as they have been shown to improve insulin resistance and reduce the risk of cardiovascular disease. In addition, their role in accelerated steroidogenesis by limiting one source of cholesterol, influencing enzymatic activity, and providing several other beneficial mechanisms is widely investigated. This review aimed to provide a comprehensive overview of the pathogenesis of androgen excess and dyslipidemia in PCOS, as well as the therapeutic potential of statins.
Coronavirus disease 2019 (COVID-19) is a highly heterogeneous disease regarding severity, vulnerability to infection due to comorbidities, and treatment approaches. The hypothalamic–pituitary–adrenal ...(HPA) axis has been identified as one of the most critical endocrine targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that might significantly impact outcomes after infection. Herein we review the rationale for glucocorticoid use in the setting of COVID-19 and emphasize the need to have a low index of suspicion for glucocorticoid-induced adrenal insufficiency, adjusting for the glucocorticoid formulation used, dose, treatment duration, and underlying health problems. We also address several additional mechanisms that may cause HPA axis dysfunction, including critical illness-related corticosteroid insufficiency, the direct cytopathic impacts of SARS-CoV-2 infection on the adrenals, pituitary, and hypothalamus, immune-mediated inflammations, small vessel vasculitis, microthrombotic events, the resistance of cortisol receptors, and impaired post-receptor signaling, as well as the dissociation of ACTH and cortisol regulation. We also discuss the increased risk of infection and more severe illness in COVID-19 patients with pre-existing disorders of the HPA axis, from insufficiency to excess. These insights into the complex regulation of the HPA axis reveal how well the body performs in its adaptive survival mechanism during a severe infection, such as SARS-CoV-2, and how many parameters might disbalance the outcomes of this adaptation.
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The essential role of the frequent coexistence of mental disorders and polycystic ovary syndrome (PCOS) is being increasingly recognized in the management of PCOS patients since it influences the ...success of weight loss interventions. Patients frequently experience disrupted eating behaviors, evidenced by the high prevalence of eating disorders in this population. Therefore, assessment and potential modification of eating disorders and eating-related behavior might be especially relevant to improve obesity treatment outcomes in this population, which remains the most efficient causal treatment in PCOS patients with high metabolic risk. Following a literature overview on common eating disorders and eating behaviors in PCOS, the aim of this review was to explore the prevalence and underlying mechanisms behind those occurrences. Understanding the clinical relevance of those associations and the addition of the assessments of eating disorders as well as eating phenotypes, eating chronotypes, and eating content as essential determinants of eating behavior could aid in the successful management of women with PCOS. In addition, the review also covers the potential of using eating disorders and eating behavior as a tool for the personalization of obesity treatment in PCOS.
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Purpose
Metformin induces GLUT-4 mRNA expression in insulin target tissues in PCOS. It is unclear how long this impact is sustained after withdrawal of metformin. We aimed to compare the effect of ...metformin withdrawal on GLUT-4 mRNA expression in subcutaneous adipose tissue after prior short (ST, 1 year,
N
= 11) and long term (LT, at least 3 years,
N
= 13) treatment in obese PCOS women.
Methods
At baseline and 6 months after withdrawal, biopsy of subcutaneous adipose tissue followed by quantitative PCR analysis was performed to determine GLUT-4 mRNA expression.
Results
We found no time/effect differences in GLUT-4 mRNA expression in ST (2
-dCt
at baseline 0.42 (0.16–0.48) vs 2
-dCt
after 6 months 0.31 (0.22–0.56),
p
= 0.594) and no time/effect difference in LT group (2
-dCt
at baseline 0.24 (0.14–0.39) vs 2
-dCt
after 6 months 0.25 (0.20–0.38),
p
= 0.382). There was also no difference in GLUT-4 mRNA expression between both groups at baseline and after 6 months.
Conclusions
In summary, 6 months after metformin withdrawal, GLUT-4 mRNA expression in subcutaneous adipose tissue remained stable, regardless of the prior treatment duration.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Polycystic ovary syndrome (PCOS) is the most prevalent endocrine and metabolic disorder in premenopausal women, characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. ...Patients frequently present comorbidities, including obesity, insulin resistance, and impaired glucose and lipid metabolism. The diverse clinical presentation may mimic various endocrine disorders, making the diagnosis challenging in some clinical circumstances. Prolactin (PRL) is a recommended biomarker in the initial diagnostic workup to rule out hyperprolactinemia (HPRL). The traditional role of PRL is linked to lactation and the reproductive system. Recent research highlights PRL’s emerging role in metabolic homeostasis. PRL influences metabolism directly by interacting with the pancreas, liver, hypothalamus, and adipose tissue. Its influence on an individual’s metabolism is intricately tied to its serum concentration. While deficient and very high levels of PRL can negatively affect metabolism, intermediate–normal to moderately high levels may promote metabolic health. In women with PCOS, PRL levels may be altered. Research results on different aspects of the relationship between PCOS and the impact of various levels of PRL on metabolic homeostasis are limited and inconsistent. In this narrative literature review, we comprehensively examined data on serum PRL levels in PCOS patients. We investigated the correlation between a favorable metabolic profile and serum PRL levels in this population. Furthermore, we explored the concept of beneficial PRL effects on metabolism and discussed the potential therapeutic application of dopamine agonists in PCOS treatment. Lastly, we emphasized several promising avenues for future research in this field.
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