Regulation of Hypoxic-Adenosinergic Signaling by Estrogen: Implications for Microvascular Injury

Adenosine metabolism and receptors in aging of the skin, musculoskeletal, immune and cardiovascular systems

Aging populations worldwide face an increasing burden of age-related chronic conditions, necessitating a deeper understanding of the underlying mechanisms. Purine metabolism has emerged as a crucial player in the pathophysiology of aging, affecting various tissues and organs. Dysregulation of purine metabolism, particularly alterations in extracellular adenosine levels and adenosine receptor signaling, contributes to age-related musculoskeletal problems, cardiovascular diseases, inflammation, and impaired immune responses. Changes in purine metabolism are associated with diminished tissue repair and regeneration, altered bone density, and impaired muscle regeneration. Mechanistically, age-related alterations in purine metabolism involve reductions in extracellular adenosine production, impaired autocrine signaling, and dysregulated expression of CD73 and CD39. Targeting adenosine receptors, such as A2A and A2B receptors, emerges as a promising therapeutic approach to mitigate age-related conditions, including sarcopenia, obesity, osteoarthritis, and impaired wound healing. Since we cannot reverse time, understanding the intricate molecular interplay between purine metabolism and aging-related pathologies holds significant potential for developing novel therapeutic strategies to improve the health and quality of life of aging populations. In this review, we compile the findings related to purine metabolism during aging in several tissues and organs and provide insights into how these signals can be manipulated to circumvent the deleterious effects of the passage of time on our body.

Diabesity alters the protective effects of estrogens on endothelial function through adipose tissue secretome

Estrogens have a well-known protective role in the development of the metabolic syndrome. Nevertheless, recent epidemiological data question the cardioprotective effect of estrogens in obese and diabetic women. In this context, white adipose tissue (WAT) becomes dysfunctional, which has an impact on the cardiovascular system. The aim of the study was to elucidate the role of 17β-estradiol (E2) in the interplay between adipose tissue and endothelial function in an animal model of diabesity. We used ZDF (fa/fa) female rats subjected to ovariectomy (OVA), OVA + E2 or sham operated, as well as non-obese non-diabetic ZDF (fa/+) rats. Endothelial function and vascular remodeling markers were assessed in the aorta, while mitochondrial function, oxidative stress, and adiponectin production were analyzed in gonadal WAT. Conditioned media from gonadal WAT explants were used to assess the effects of WAT secretome on HUVEC. Additionally, the adiponectin receptor agonist AdipoRON and E2 were utilized to examine potential interactions. Ovariectomy ameliorated the WAT dysfunction associated to the obese and diabetic state and promoted adiponectin secretion, effects that were linked to a reduction of endothelial dysfunction and inflammatory markers in the aorta of OVA rats and in HUVEC treated with OVA-conditioned media. Our findings provide evidence supporting the idea that in the context of obesity and diabetes, ovariectomy improves WAT secretome and positively impacts endothelial function, suggesting a detrimental role for E2. Additionally, our results point to adiponectin as the primary driver of the effects exerted by ovariectomy on the adipovascular axis.

The influence of estrogen on myocardial post-translational modifications and cardiac function in women

The lifetime risk of heart failure (HF) is comparable in men and women; nevertheless, disparities exist in our understanding of how HF differs between sexes. Several differences in cardiac physiology exist between men and women including the propensity to develop specific HF phenotypes. Men are more likely to be diagnosed with HF failure with reduced ejection fraction, while women have a greater propensity to develop HF with preserved ejection fraction. The mechanisms responsible for these differences remain unclear. Post-translational modifications (PTMs) of myofilament proteins likely contribute to these sex-specific propensities. The role of PTMs in heart disease is an expanding field with immense potential therapeutic targets. However, numerous PTMs remain underexplored, particularly in the context of the female heart. Estrogen, a key gonadal hormone, cardioprotective in pre-menopausal women and its loss with menopause likely contributes to disease in aging women. However, how estrogen regulates PTMs to contribute to HF development is not fully clear. This review outlines key sex differences in HF along with characterizing the contributions of novel myocardial PTMs in cardiac physiology and their regulation by estrogen. Collectively, we highlight the necessity for further investigation into women's heart health and the distinctive mechanisms distinguishing women from men.