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Anaesthesiology Intensive Therapy 2021Critically ill patients are often presumed to be in a state of "constant dehydration" or in need of fluid, thereby justifying a continuous infusion with some form of... (Review)
Review
Critically ill patients are often presumed to be in a state of "constant dehydration" or in need of fluid, thereby justifying a continuous infusion with some form of intravenous (IV) fluid, despite their clinical data suggesting otherwise. Overzealous fluid administration and subsequent fluid accumulation and overload are associated with poorer outcomes. Fluids are drugs, and their use should be tailored to meet the patient's individualized needs; fluids should never be given as routine maintenance unless indicated. Before prescribing any fluids, the physician should consider the patient's characteristics and the nature of the illness, and assess the risks and benefits of fluid therapy. Decisions regarding fluid therapy present a daily challenge in many hospital departments: emergency rooms, regular wards, operating rooms, and intensive care units. Traditional fluid prescription is full of paradigms and unnecessary routines as well as malpractice in the form of choosing the wrong solutions for maintenance or not meeting daily requirements. Prescribing maintenance fluids for patients on oral intake will lead to fluid creep and fluid overload. Fluid overload, defined as a 10% increase in cumulative fluid balance from baseline weight, is an independent predictor for morbidity and mortality, and thus hospital cost. In the last decade, increasing evidence has emerged supporting a restrictive fluid approach. In this manuscript, we aim to provide a pragmatic description of novel concepts related to the use of IV fluids in critically ill patients, with emphasis on the different indications and common clinical scenarios. We also discuss active deresuscitation, or the timely cessation of fluid administration, with the intention of achieving a zero cumulative fluid balance.
Topics: Critical Illness; Fluid Therapy; Humans; Intensive Care Units; Pharmaceutical Preparations; Water-Electrolyte Balance
PubMed: 34006046
DOI: 10.5114/ait.2021.105252 -
Nutrients Dec 2018Water is essential for metabolism, substrate transport across membranes, cellular homeostasis, temperature regulation, and circulatory function. Although nutritional and... (Review)
Review
Water is essential for metabolism, substrate transport across membranes, cellular homeostasis, temperature regulation, and circulatory function. Although nutritional and physiological research teams and professional organizations have described the daily total water intakes (TWI, L/24h) and Adequate Intakes (AI) of children, women, and men, there is no widespread consensus regarding the human water requirements of different demographic groups. These requirements remain undefined because of the dynamic complexity inherent in the human water regulatory network, which involves the central nervous system and several organ systems, as well as large inter-individual differences. The present review analyzes published evidence that is relevant to these issues and presents a novel approach to assessing the daily water requirements of individuals in all sex and life-stage groups, as an alternative to AI values based on survey data. This empirical method focuses on the intensity of a specific neuroendocrine response (e.g., plasma arginine vasopressin (AVP) concentration) employed by the brain to regulate total body water volume and concentration. We consider this autonomically-controlled neuroendocrine response to be an inherent hydration biomarker and one means by which the brain maintains good health and optimal function. We also propose that this individualized method defines the elusive state of euhydration (i.e., water balance) and distinguishes it from hypohydration. Using plasma AVP concentration to analyze multiple published data sets that included both men and women, we determined that a mild neuroendocrine defense of body water commences when TWI is ˂1.8 L/24h, that 19⁻71% of adults in various countries consume less than this TWI each day, and consuming less than the 24-h water AI may influence the risk of dysfunctional metabolism and chronic diseases.
Topics: Body Water; Dehydration; Drinking; Humans; Water-Electrolyte Balance
PubMed: 30563134
DOI: 10.3390/nu10121928 -
Biochemical Society Transactions Feb 2016Inorganic polyphosphate (polyP) accumulates in acidocalcisomes, acidic calcium stores that have been found from bacteria to human cells. Proton pumps, such as the... (Review)
Review
Inorganic polyphosphate (polyP) accumulates in acidocalcisomes, acidic calcium stores that have been found from bacteria to human cells. Proton pumps, such as the vacuolar proton pyrophosphatase (V-H(+)-PPase or VP1), the vacuolar proton ATPase (V-H(+)-ATPase) or both, maintain their acidity. A vacuolar transporter chaperone (VTC) complex is involved in the synthesis and translocation of polyP to these organelles in several eukaryotes, such as yeast, trypanosomatids, Apicomplexan and algae. Studies in trypanosomatids have revealed the role of polyP and acidocalcisomes in osmoregulation and calcium signalling.
Topics: Animals; Calcium; Humans; Ion Channels; Membrane Transport Proteins; Organelles; Osmoregulation; Polyphosphates
PubMed: 26862180
DOI: 10.1042/BST20150193 -
Journal of General Internal Medicine Sep 2022
Topics: Humans; Internal Medicine; Water Loss, Insensible
PubMed: 35771401
DOI: 10.1007/s11606-022-07700-4 -
Pediatric Nephrology (Berlin, Germany) Aug 2020In recent times, the traditional nephrocentric, two-compartment model of body sodium has been challenged by long-term sodium balance studies and experimental work on the... (Review)
Review
In recent times, the traditional nephrocentric, two-compartment model of body sodium has been challenged by long-term sodium balance studies and experimental work on the dermal interstitium and endothelial surface layer. In the new paradigm, sodium can be stored without commensurate water retention in the interstitium and endothelial surface layer, forming a dynamic third compartment for sodium. This has important implications for sodium homeostasis, osmoregulation and the hemodynamic response to salt intake. Sodium storage in the skin and endothelial surface layer may function as a buffer during periods of dietary depletion and excess, representing an extra-renal mechanism regulating body sodium and water. Interstitial sodium storage may also serve as a biomarker for sodium sensitivity and cardiovascular risk, as well as a target for hypertension treatment. Furthermore, sodium storage may explain the limitations of traditional techniques used to quantify sodium intake and determine infusion strategies for dysnatraemias. This review is aimed at outlining these new insights into sodium homeostasis, exploring their implications for clinical practice and potential areas for further research for paediatric and adult populations.
Topics: Body Water; Endothelial Cells; Female; Homeostasis; Humans; Kidney; Male; Skin; Sodium; Water-Electrolyte Balance
PubMed: 31363839
DOI: 10.1007/s00467-019-04305-8 -
Annual Review of Physiology Feb 2024The cytoplasm is densely packed with molecules that contribute to its nonideal behavior. Cytosolic crowding influences chemical reaction rates, intracellular water... (Review)
Review
The cytoplasm is densely packed with molecules that contribute to its nonideal behavior. Cytosolic crowding influences chemical reaction rates, intracellular water mobility, and macromolecular complex formation. Overcrowding is potentially catastrophic; to counteract this problem, cells have evolved acute and chronic homeostatic mechanisms that optimize cellular crowdedness. Here, we provide a physiology-focused overview of molecular crowding, highlighting contemporary advances in our understanding of its sensing and control. Long hypothesized as a form of crowding-induced microcompartmentation, phase separation allows cells to detect and respond to intracellular crowding through the action of biomolecular condensates, as indicated by recent studies. Growing evidence indicates that crowding is closely tied to cell size and fluid volume, homeostatic responses to physical compression and desiccation, tissue architecture, circadian rhythm, aging, transepithelial transport, and total body electrolyte and water balance. Thus, molecular crowding is a fundamental physiologic parameter that impacts diverse functions extending from molecule to organism.
Topics: Humans; Water-Electrolyte Balance; Water
PubMed: 37931170
DOI: 10.1146/annurev-physiol-042222-025920 -
Comparative Biochemistry and... Mar 2021August Krogh's studies of the frog identified the respiratory function of the skin in 1904 and the osmoregulatory function of the skin in 1937. It is the thesis of my... (Review)
Review
August Krogh's studies of the frog identified the respiratory function of the skin in 1904 and the osmoregulatory function of the skin in 1937. It is the thesis of my review that the osmoregulatory function of the skin has evolved for meeting quite different demands. In freshwater the body fluid homeostasis is challenged by loss of ions to the environment. This is compensated for by active ion uptake energized by the sodium-pump ATPase and the V-type proton pump ATPase. I conclude that Krogh's astonishing observation of cutaneous chloride uptake from μM concentrations of NaCl is compatible with the free energy changes of ATP hydrolysis catalyzed by the sodium‑potassium pump ATPase and the V-type proton pump ATPase operating in series, and in parallel with experimentally verified vanishingly small leak fluxes. On land the frog is challenged by evaporative water loss through the highly water permeable skin, similar to the water permeable conducting airways of terrestrial vertebrates including man. The epithelia serving respiratory gas exchanges are heterocellular and have molecular, structural and functional properties in common. The cutaneous surface liquid of amphibians evolved for protecting the skin epithelium from desiccation like the airway surface liquid of the lung. Published studies of ion transport mechanisms of acinar cells and the two types of epithelial cells, lead to the hypothesis that subepithelial gland secretion, evaporative water loss, and ion reabsorption by the epithelium regulate composition and volume of the cutaneous surface liquid.
Topics: Animals; Anura; Epithelial Cells; Epithelium; Ion Transport; Osmoregulation; Skin Physiological Phenomena; Sodium-Potassium-Exchanging ATPase; Vacuolar Proton-Translocating ATPases; Water-Electrolyte Balance
PubMed: 33326845
DOI: 10.1016/j.cbpa.2020.110869 -
Nutrients Apr 2023One of the most common cyclitols found in eukaryotic cells-Myo-inositol (MI) and its derivatives play a key role in many cellular processes such as ion channel... (Review)
Review
One of the most common cyclitols found in eukaryotic cells-Myo-inositol (MI) and its derivatives play a key role in many cellular processes such as ion channel physiology, signal transduction, phosphate storage, cell wall formation, membrane biogenesis and osmoregulation. The aim of this paper is to characterize the possibility of neurodegenerative disorders treatment using MI and the research of other therapeutic methods linked to MI's derivatives. Based on the reviewed literature the researchers focus on the most common neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and Spinocerebellar ataxias, but there are also works describing other seldom encountered diseases. The use of MI, d-pinitol and other methods altering MI's metabolism, although research on this topic has been conducted for years, still needs much closer examination. The dietary supplementation of MI shows a promising effect on the treatment of neurodegenerative disorders and can be of great help in alleviating the accompanying depressive symptoms.
Topics: Humans; Cyclitols; Alzheimer Disease; Eukaryotic Cells; Huntington Disease; Osmoregulation
PubMed: 37432155
DOI: 10.3390/nu15092029 -
FEMS Yeast Research Aug 2022In response to osmotic dehydration cells sense, signal, alter gene expression, and metabolically counterbalance osmotic differences. The main compatible solute/osmolyte... (Review)
Review
In response to osmotic dehydration cells sense, signal, alter gene expression, and metabolically counterbalance osmotic differences. The main compatible solute/osmolyte that accumulates in yeast cells is glycerol, which is produced from the glycolytic intermediate dihydroxyacetone phosphate. This review covers recent advancements in understanding mechanisms involved in sensing, signaling, cell-cycle delays, transcriptional responses as well as post-translational modifications on key proteins in osmoregulation. The protein kinase Hog1 is a key-player in many of these events, however, there is also a growing body of evidence for important Hog1-independent mechanisms playing vital roles. Several missing links in our understanding of osmoregulation will be discussed and future avenues for research proposed. The review highlights that this rather simple experimental system-salt/sorbitol and yeast-has developed into an enormously potent model system unravelling important fundamental aspects in biology.
Topics: Glycerol; Osmoregulation; Osmotic Pressure; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Water-Electrolyte Balance
PubMed: 35927716
DOI: 10.1093/femsyr/foac035 -
Journal of the American Society of... Jul 2019Kidney transplant recipients have an impaired ability to dilute urine but seldom develop baseline hyponatremia before ESRD. Although hyponatremia is a risk factor for...
BACKGROUND
Kidney transplant recipients have an impaired ability to dilute urine but seldom develop baseline hyponatremia before ESRD. Although hyponatremia is a risk factor for adverse events in CKD and in kidney transplant recipients, it remains unclear whether subtler alterations in osmoregulation performance are associated with outcome.
METHODS
We studied a single-center prospective cohort of 1258 kidney transplant recipients who underwent a water-loading test 3 months after transplant to determine osmoregulation performance. Measured GFR (mGFR) was performed at the same visit. A group of 164 healthy candidates for kidney donation served as controls. We further evaluated the association of osmoregulation performance with transplantation outcomes and subsequent kidney function.
RESULTS
Unlike controls, most kidney transplant recipients failed to maintain plasma sodium during water loading (plasma sodium slope of -0.6±0.4 mmol/L per hour in transplant recipients versus -0.12±0.3 mmol/L per hour in controls; <0.001). Steeper plasma sodium reduction during the test independently associated with the composite outcome of all-cause mortality and allograft loss (hazard ratio [HR], 1.73 per 1 mmol/L per hour decrease in plasma sodium; 95% confidence interval [95% CI], 1.23 to 2.45; =0.002) and allograft loss alone (HR, 2.04 per 1 mmol/L per hour decrease in plasma sodium; 95% CI, 1.19 to 3.51; =0.01). The association remained significant in a prespecified sensitivity analysis excluding patients with hyperglycemia. In addition, a steeper plasma sodium slope 3 months after transplantation independently correlated with lower mGFR at 12 months (=1.93; 95% CI, 0.46 to 3.41; =0.01).
CONCLUSIONS
Reduced osmoregulation performance occurs frequently in kidney transplant recipients and is an independent predictor of renal outcome.
Topics: Glomerular Filtration Rate; Humans; Kidney Transplantation; Osmoregulation; Prospective Studies; Sodium; Transplantation, Homologous
PubMed: 31217325
DOI: 10.1681/ASN.2018121269