Comparison of Isotonic Activation of Cell Volume Regulation in Rat Peritoneal Mesothelial Cells and in Kidney Outer Medullary Collecting Duct Principal Cells

Long-term health outcomes associated with hydration status

Body water balance is determined by fundamental homeostatic mechanisms that maintain stable volume, osmolality and the composition of extracellular and intracellular fluids. Water balance is maintained by multiple mechanisms that continuously match water losses through urine, the skin, the gastrointestinal tract and respiration with water gains achieved through drinking, eating and metabolic water production. Hydration status is determined by the state of the water balance. Underhydration occurs when a decrease in body water availability, due to high losses or low gains, stimulates adaptive responses within the water balance network that are aimed at decreasing losses and increasing gains. This stimulation is also accompanied by cardiovascular adjustments. Epidemiological and experimental studies have linked markers of low fluid intake and underhydration - such as increased plasma concentration of vasopressin and sodium, as well as elevated urine osmolality - with an increased risk of new-onset chronic diseases, accelerated aging and premature mortality, suggesting that persistent activation of adaptive responses may be detrimental to long-term health outcomes. The causative nature of these associations is currently being tested in interventional trials. Understanding of the physiological responses to underhydration may help to identify possible mechanisms that underlie potential adverse, long-term effects of underhydration and inform future research to develop preventative and treatment approaches to the optimization of hydration status.

The Integral Role of Chloride & With-No-Lysine Kinases in Cell Volume Regulation & Hypertension

Chloride anions are the most abundant in humans. For many years, it has been believed that chloride is simply a counterion of all other cations, ensuring the electroneutrality of the extracellular space. Recent data suggests that chloride anions possess a broad spectrum of important activities that regulate vital cellular functions. It is now evident that, apart from its contribution to the electroneutrality of the extracellular space, it acts as an osmole and contributes to extracellular and intracellular volume regulation. Its anionic charge also contributes to the generation of cell membrane potential. The most interesting action of chloride anions is their ability to regulate the activity of with-no-lysine kinases, which in turn regulate the activity of sodium chloride and potassium chloride cotransporters and govern the reabsorption of salt and excretion of potassium by nephron epithelia. Chloride anions seem to play a crucial role in cell functions, such as cell volume regulation, sodium reabsorption in the distal nephron, potassium balance, and sodium sensitivity, which lead to hypertension. All of these functions are accomplished on a molecular level via complicated metabolic pathways, many of which remain poorly defined. We attempted to elucidate some of these pathways in light of recent advances in our knowledge, obtained mainly from experimental studies.

Role of Peritoneal Mesothelial Cells in the Progression of Peritoneal Metastases

Peritoneal metastatic cancer comprises a heterogeneous group of primary tumors that originate in the peritoneal cavity or metastasize into the peritoneal cavity from a different origin. Metastasis is a characteristic of end-stage disease, often indicative of a poor prognosis with limited treatment options. Peritoneal mesothelial cells (PMCs) are a thin layer of cells present on the surface of the peritoneum. They display differentiated characteristics in embryonic development and adults, representing the first cell layer encountering peritoneal tumors to affect their progression. PMCs have been traditionally considered a barrier to the intraperitoneal implantation and metastasis of tumors; however, recent studies indicate that PMCs can either inhibit or actively promote tumor progression through distinct mechanisms. This article presents a review of the role of PMCs in the progression of peritoneum implanted tumors, offering new ideas for therapeutic targets and related research.

Molecular Mechanisms of Peritoneal Membrane Pathophysiology

The peritoneal membrane is the largest internal membrane of the human body, having a surface area that approximates the surface area of the skin [...]