Complementary Role of Oxytocin and Vasopressin in Cardiovascular Regulation

The neurons secreting oxytocin (OXY) and vasopressin (AVP) are located mainly in the supraoptic, paraventricular, and suprachiasmatic nucleus of the brain. Oxytocinergic and vasopressinergic projections reach several regions of the brain and the spinal cord. Both peptides are released from axons, soma, and dendrites and modulate the excitability of other neuroregulatory pathways. The synthesis and action of OXY and AVP in the peripheral organs (eye, heart, gastrointestinal system) is being investigated. The secretion of OXY and AVP is influenced by changes in body fluid osmolality, blood volume, blood pressure, hypoxia, and stress. Vasopressin interacts with three subtypes of receptors: V1aR, V1bR, and V2R whereas oxytocin activates its own OXTR and V1aR receptors. AVP and OXY receptors are present in several regions of the brain (cortex, hypothalamus, pons, medulla, and cerebellum) and in the peripheral organs (heart, lungs, carotid bodies, kidneys, adrenal glands, pancreas, gastrointestinal tract, ovaries, uterus, thymus). Hypertension, myocardial infarction, and coexisting factors, such as pain and stress, have a significant impact on the secretion of oxytocin and vasopressin and on the expression of their receptors. The inappropriate regulation of oxytocin and vasopressin secretion during ischemia, hypoxia/hypercapnia, inflammation, pain, and stress may play a significant role in the pathogenesis of cardiovascular diseases.

Cardiovascular Regulation of the Elderly in Low Oxygenation Environments: A Narrative Review

Hypobaric hypoxia originates from the exposure of predominantly aerobic organisms to environments with low availability of atmospheric oxygen, however, prolonged exposures to hypoxic environments without previous experience or preparation can generate an atypical and possibly harmful physiological response to organic systems, mainly in older audiences. Thus, this study aimed to describe the main adaptive effects on cardiovascular control in hypoxic environments in elderly people with cardiovascular dysfunction. To carry out this study, a bibliographic survey was made on the virtual database Medline by PubMed, the protocol used to search for the studies was done through the selection of previously defined keywords. For the analysis of the data, the method of full description of the results of the selected works was adopted. It can be concluded that exposure to hypoxic environments directly and negatively influenced the cardiovascular regulation and cardiac behavior of the elderly, in which this episode worsened in the presence of comorbidities.

Study Progression of Apelin/APJ Signaling and Apela in Different Types of Cancer

Apelin is an endogenous ligand that binds to the G protein-coupled receptor angiotensin-like-receptor 1 (APJ). Apelin and APJ are widely distributed in organs and tissues and are involved in multiple physiological and pathological processes including cardiovascular regulation, neuroendocrine stress response, energy metabolism, etc. Additionally, apelin/APJ axis was found to play an important role in cancer development and progression. Apela is a newly identified endogenous ligand for APJ. Several studies have revealed the potential role of Apela in cancers. In this article, we review the current studies focusing on the role of apelin/APJ signaling and Apela in different cancers. Potential mechanisms by which apelin/APJ and Apela mediate the regulation of cancer development and progression were also mentioned. The Apelin/APJ signaling and Apela may serve as potential therapeutic candidates for treatment of cancer.

ACE2, a multifunctional protein – from cardiovascular regulation to COVID-19

This Editorial, written by Guest Editors Professor Michael Bader, Professor Anthony J. Turner and Dr Natalia Alenina, proudly introduces the Clinical Science-themed collection on angiotensin-converting enzyme 2 (ACE2), a multifunctional protein – from cardiovascular regulation to coronavirus disease 2019 (COVID-19).