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Kidney International Apr 2014Current teaching states that when sodium intake is increased from low to high levels, total-body sodium (TBNa) and water increase until daily sodium excretion again... (Review)
Review
Current teaching states that when sodium intake is increased from low to high levels, total-body sodium (TBNa) and water increase until daily sodium excretion again equals intake. When sodium intake is reduced, sodium excretion briefly exceeds intake until the excess TBNa and water are eliminated, at which point sodium excretion again equals intake. However, careful balance studies oftentimes conflict with this view and long-term studies suggest that TBNa fluctuates independent of intake or body weight. We recently performed the opposite experiment in that we fixed sodium intake for several weeks at three levels of sodium intake and collected all urine made. We found weekly (circaseptan) patterns in sodium excretion that were inversely related to aldosterone and directly to cortisol. TBNa was not dependent on sodium intake but instead exhibited far longer (≥ monthly) infradian rhythms independent of extracellular water, body weight, or blood pressure. The findings are consistent with our ideas on tissue sodium storage and its regulation that we developed on the basis of animal research. We are implementing (23)Na-magnetic resonance imaging (MRI) to pursue open questions on sodium balance in patients. Our findings could be relevant to therapeutic strategies for hypertension and target-organ damage.
Topics: Animals; Humans; Sodium; Water-Electrolyte Balance
PubMed: 24107854
DOI: 10.1038/ki.2013.367 -
Lancet (London, England) Jul 1998Disorders of serum sodium are both the most common and probably most the poorly understood electrolyte disorders in clinical medicine. In the past few years increased... (Review)
Review
Disorders of serum sodium are both the most common and probably most the poorly understood electrolyte disorders in clinical medicine. In the past few years increased knowledge about the non-osmotic release of vasopressin and the cloning of vasopressin receptors and of vasopressin-regulated water channels (AQP2) has enhanced our understanding of these disorders. Also controversies surrounding the treatment of hyponatraemic patients have led to well-accepted therapeutic guidelines.
Topics: Diabetes Insipidus; Humans; Hypernatremia; Hyponatremia; Osmolar Concentration; Sodium
PubMed: 9683227
DOI: 10.1016/S0140-6736(97)12169-9 -
NMR in Biomedicine Feb 2016One of the main tasks of the human kidneys is to maintain the homeostasis of the body's fluid and electrolyte balance by filtration of the plasma and excretion of the... (Review)
Review
One of the main tasks of the human kidneys is to maintain the homeostasis of the body's fluid and electrolyte balance by filtration of the plasma and excretion of the end products. Herein, the regulation of extracellular sodium in the kidney is of particular importance. Sodium MRI ((23)Na MRI) allows for the absolute quantification of the tissue sodium concentration (TSC) and thereby provides a direct link between TSC and tissue viability. Renal (23)Na MRI can provide new insights into physiological tissue function and viability thought to differ from the information obtained by standard (1)H MRI. Sodium imaging has the potential to become an independent surrogate biomarker not only for renal imaging, but also for oncology indications. However, this technique is now on the threshold of clinical implementation. Numerous, initial pre-clinical and clinical studies have already outlined the potential of this technique; however, future studies need to be extended to larger patient groups to show the diagnostic outcome. In conclusion, (23)Na MRI is seen as a powerful technique with the option to establish a non-invasive renal biomarker for tissue viability, but is still a long way from real clinical implementation.
Topics: Animals; Humans; Kidney; Magnetic Resonance Imaging; Sodium; Sodium Isotopes
PubMed: 25728879
DOI: 10.1002/nbm.3274 -
Journal of Veterinary Diagnostic... Mar 2021Fatal sodium intoxication can occur in many species, including cattle, and postmortem confirmation often includes brain sodium concentration determination. Published...
Fatal sodium intoxication can occur in many species, including cattle, and postmortem confirmation often includes brain sodium concentration determination. Published information regarding brain sodium distribution in cattle was not found in a literature review. Our study was designed to determine whether sodium is uniformly distributed throughout the bovine brain. Eight whole bovine brains were collected from adult cattle with no neurologic signs or history suggestive of sodium intoxication, and with a non-neurologic cause of death diagnosed on gross examination. Brains were divided mid-sagittally. One hemisphere of each brain was homogenized. Subsamples were obtained from the remaining hemisphere (rostral, caudal, and dorsal cerebral cortices; brainstem, thalamus, and cerebellum). Sodium concentrations of regions and homogenates were measured by inductively coupled plasma-mass spectrometry. Data were analyzed using repeated measures ANOVA with a pairwise post-test to compare mean sodium concentration of each region to mean homogenate sodium concentration. Brain sodium was not uniformly distributed; sodium concentrations in different regions of the same brain varied somewhat unpredictably. Homogenization of an entire brain hemisphere appears to be the ideal method of sample preparation to ensure accurate brain sodium concentration measurement in adult cattle.
Topics: Animals; Brain; Cattle; Cattle Diseases; Sodium
PubMed: 33357005
DOI: 10.1177/1040638720982989 -
Seminars in Dialysis 2003Water and sodium overload is the predominant factor in the pathogenesis of hypertension in dialysis patients. In many dialysis patients, dry weight is not reached... (Review)
Review
Water and sodium overload is the predominant factor in the pathogenesis of hypertension in dialysis patients. In many dialysis patients, dry weight is not reached because of an imbalance between the interdialytic accumulation of water and sodium and the brief and discontinuous nature of routine dialysis therapy. During dialysis, sodium is removed by convection and to a lesser degree by diffusion. However, with supraphysiologic dialysate sodium concentrations, diffusive influx from dialysate may occur, especially in patients with low predialytic plasma sodium concentrations. Measuring sodium removal during dialysis is difficult and hampered by the variability in conventional sodium measurements. Ionic mass removal by continuous measurement of conductivity in the dialysate ports appears to be a promising tool for the approximation of sodium removal during dialysis. While the beneficial effects of concomitant water and sodium removal on blood pressure control in dialysis patients are undisputed, it is less well known whether a change in hydrosodium balance solely by reducing dialysate sodium is beneficial. Considering the inherent dangers of such an approach (intradialytic hemodynamic instability), the beneficial effects of strict dietary sodium restriction appear to be of much larger clinical benefit. It has become possible to individualize dialysate sodium concentration by means of online measurements of plasma conductivity and adjustment of dialysate conductivity by feedback technologies. The clinical benefits of this approach deserve further study. Still, reducing dietary sodium intake remains the most important tool in improving blood control in dialysis patients.
Topics: Blood Pressure; Dialysis Solutions; Humans; Hypotension; Renal Dialysis; Sodium; Water-Electrolyte Balance
PubMed: 12969379
DOI: 10.1046/j.1525-139x.2003.16070.x -
Current Hypertension Reports Oct 2013Elevation of blood pressure (BP) and the risk for progression to hypertension (HTN) is of increasing concern in children and adolescents. Indeed, it is increasingly... (Review)
Review
Elevation of blood pressure (BP) and the risk for progression to hypertension (HTN) is of increasing concern in children and adolescents. Indeed, it is increasingly recognized that target organ injury may begin with even low levels of BP elevation. Sodium intake has long been recognized as a modifiable risk factor for HTN. While it seems clear that sodium impacts BP in children, its effects may be enhanced by other factors including obesity and increasing age. Evidence from animal and human studies indicates that sodium may have adverse consequences on the cardiovascular system independent of HTN. Thus, moderation of sodium intake over a lifetime may reduce risk for cardiovascular morbidity in adulthood. An appetite for salt is acquired, and intake beyond our need is almost universal. Considering that eating habits in childhood have been shown to track into adulthood, modest sodium intake should be advocated as part of a healthy lifestyle.
Topics: Animals; Blood Pressure; Child; Humans; Hypertension; Life Style; Risk Factors; Sodium
PubMed: 23949320
DOI: 10.1007/s11906-013-0382-z -
Seminars in Dialysis Mar 2014Oligo-anuric patients with end-stage kidney disease are dependent on hemodialysis to achieve and maintain the desired goal of euvolemia. The dialysis prescription, in... (Review)
Review
Oligo-anuric patients with end-stage kidney disease are dependent on hemodialysis to achieve and maintain the desired goal of euvolemia. The dialysis prescription, in addition to sodium and fluid restriction, is therefore a critically important factor in the care of hemodialysis patients. Various dialysate sodium concentrations have been favored throughout the history of dialysis, but the "optimal" concentration remains unclear. In this manuscript, we examine the historical context of changes to the dialysate sodium prescription, review the evidence of its associated effects, discuss 'individualization' of dialysate sodium, and highlight the need for definitive trials that are powered for important clinical outcomes.
Topics: Algorithms; Dialysis Solutions; Humans; Renal Dialysis; Sodium
PubMed: 24450281
DOI: 10.1111/sdi.12182 -
PloS One 2017Excess dietary sodium is associated with increased blood pressure (BP). Some drugs are associated with high sodium intake (in particular effervescent tablets), but the... (Review)
Review
BACKGROUND
Excess dietary sodium is associated with increased blood pressure (BP). Some drugs are associated with high sodium intake (in particular effervescent tablets), but the cardiovascular risk associated with such high sodium-containing drugs (HSCD) is largely underevaluated.
OBJECTIVES
To summarize the evidence for a potential cardiovascular risk associated with exposure to HSCD, and to highlight possible risk factors associated with this iatrogenic issue; in general and/or specific populations.
METHODS
We conducted a systematic review, by searching electronic databases including MEDLINE, EMBASE, Web of Science, CENTRAL and grey literature between 1960 and 2015. We included studies that reported modification of cardiovascular parameters or incidence/prevalence of cardiovascular outcomes, between a group of subjects exposed to HSCD relative to a non-exposed group. The threshold used to identify HSCD was 391 mg/day. We did not consider studies evaluating exposure to sodium as an active ingredient or those focusing on dialysis solutions or enteral/parenteral nutrition. Study quality was assessed using the EPHPP tool.
RESULTS
A total of eight studies met our inclusion criteria. Four reported results for short-term exposure to HSCD (≤ 7 days) on BP fluctuations. One study reported an elevation of BP (associated sodium intake: 1,656 mg/day). Four studies evaluated a long-term exposure (≥ 2 years or discontinuation of a chronic treatment). Two studies reported iatrogenic risk. For these studies, drug associated sodium intake was high (> 1,500 mg/day) in patients with comorbidities (in particular, diabetes mellitus and hypertension).
CONCLUSION
Despite numerous study limitations, this systematic review suggests three potential synergistic risk factors for cardiovascular complications after exposure to HSCD: a high sodium intake (≥ 1,500 mg/day), a long duration of exposure, and the presence of comorbidities. Further studies are required to characterize this iatrogenic risk.
TRIAL REGISTRATION
PROSPERO CRD42016047086.
Topics: Cardiovascular Diseases; Humans; Pharmaceutical Preparations; Sodium
PubMed: 28683120
DOI: 10.1371/journal.pone.0180634 -
American Journal of Physiology.... Dec 2017Dysregulation of sodium (Na) balance is a major cause of hypertensive cardiovascular disease. The current dogma is that interstitial Na readily equilibrates with plasma... (Review)
Review
Dysregulation of sodium (Na) balance is a major cause of hypertensive cardiovascular disease. The current dogma is that interstitial Na readily equilibrates with plasma and that renal excretion and reabsorption is sufficient to regulate extracellular fluid volume and control blood pressure. These ideas have been recently challenged by the discovery that Na accumulates in tissues without commensurate volume retention and activates immune cells, leading to hypertension and autoimmune disease. However, objections have been raised to this new paradigm, with some investigators concerned about where and how salt is stored in tissues. Further concerns also include how Na is mobilized from tissue stores and how it interacts with various organ systems to cause hypertension and end-organ damage. This review assesses these two paradigms of Na regulation in the context of inflammation-mediated hypertension and cardiovascular disease pathogenesis. Also highlighted are future perspectives and important gaps in our understanding of how Na is linked to inflammation and hypertension. Understanding mechanisms of salt and body fluid regulation is the sine qua non of research efforts to identify therapeutic targets for hypertension and cardiovascular disease.
Topics: Animals; Humans; Hypertension; Immune System; Inflammation; Sodium; Sodium, Dietary
PubMed: 28931546
DOI: 10.1152/ajpregu.00250.2017 -
The Journal of Nutrition Mar 2017Accurate monitoring of sodium intake is necessary for evaluating strategies used to reduce sodium intake. However, no repeat survey has been conducted in representative... (Review)
Review
Accurate monitoring of sodium intake is necessary for evaluating strategies used to reduce sodium intake. However, no repeat survey has been conducted in representative populations in Japan to examine trends in sodium intake with the use of 24-h urinary sodium excretion, a standard evaluation method for sodium intake monitoring. The objective of this study was to examine potential trends in sodium intake by examining previous reports of 24-h urinary sodium excretion in healthy Japanese adult populations. We systematically searched for reports of 24-h urinary sodium excretion in healthy Japanese adult populations (mean age range: 18-69 y). We searched PubMed and Web of Science for English-language articles and hand-searched 7 Japanese scientific journals for Japanese-language articles. Trends in urinary sodium excretion were examined with the use of weighted linear regression and random-effects meta-regression analyses, with adjustment or stratification to address study characteristics (population mean age, percentage of men, and sample size) and study assessment for completeness of urine collection. We identified 68 reports of urinary sodium excretion from 53 articles published from 1953 through 2014 that showed high rates of urinary sodium excretion in healthy Japanese adult populations (weighted mean: 4900 mg/d). The rate of urinary sodium excretion significantly decreased between 1953 and 2014, by 4350 mg/d ( < 0.001); however, the rate of reduction in urinary sodium excretion was variable and decreased with time (-linear trend <0.001 and -quadratic trend <0.001). In the random-effects meta-regression analysis of studies that assessed completeness of urine collection with creatinine excretion, no significant relation between urinary sodium excretion and year was observed from 1978 to 2014 (β = -16, = 0.40). Despite a decrease in urinary sodium excretion in healthy Japanese adult populations between 1953 and 2014, sodium intake still exceeds the WHO recommendation for adults. This review was registered at PROSPERO as CRD42016035452.
Topics: Humans; Sodium; Sodium, Dietary; World Health Organization; Young Adult
PubMed: 28100605
DOI: 10.3945/jn.116.240960