Chronic unpredictable mild stress increases serum aldosterone without affecting corticosterone levels and induces hepatic steatosis and renal injury in young adult male rats

Stress is often associated with anxiety and depressive symptoms in adolescents. Stress is associated with components of metabolic syndrome and inflammation. The present study hypothesizes that aldosterone, more than corticosterone, promotes chronic stress-hepatic steatosis and fibrosis, as well as renal inflammation and fibrosis in young adult rats. Thirty-two young adult male Wistar rats of 51 days old were divided into four groups (n = 8 per group): Control (C), chronic unpredictable mild stress (CUMS), control plus vehicle (C plus veh), CUMS plus eplerenone, a selective aldosterone blocker (CUMS plus EP). On postnatal day 51, eplerenone was administered orally through a gastric tube two hours before the start of the stress test. The CUMS paradigm was administered once daily at different times, with no repetition of the stressor sequence for four weeks. Renal inflammation and fibrosis were measured, as well as liver glycogen, triacylglycerol, and fibrosis levels. The serum concentrations of corticosterone, aldosterone, sodium, and creatinine were measured in urine and serum. The CUMS group showed a high level of serum aldosterone without affecting the level of corticosterone, increased urinary sodium, tubular atrophy, glomerular sclerosis, the presence of inflammation, and fibrosis, without affecting creatinine, increased glycogen content, triacylglycerol, and moderate fibrosis in the liver, and treatment with eplerenone prevented the inflammation, fibrosis, glycogen, and triacylglycerol. Our results show that chronic stress-induced aldosterone promotes hepatic steatosis and renal injury more than corticosterone. The prevention by eplerenone supports our hypothesis.

Evaluation of simple diagnostic parameters in acute kidney injury in hospitalized patients-diagnostic recommendations for non-nephrologists

Acute kidney injury (AKI) is very common in hospitalized patients, affecting patient's mortality and morbidity. Major causes are prerenal AKI and acute tubular necrosis (ATN). Even though a variety of parameters/indices exist, their reliability and practicability are controversial: in fact, there is a need for a simple diagnostic approach for AKI in in-patients with parameters easily obtained in any hospital. The objective of the study was: (1) to assess reliability of simple laboratory parameters/indices to differentiate pre-/intrarenal AKI; (2) to evaluate the most reliable and feasible parameters/indices; and (3) to identify the possible impact of confounding factors. Retrospectively, in-patients with AKI hospitalized in 2020 in a university nephrology department were included. Spot urine and 24-h collection urine was analyzed with urine sodium (UNa), urine specific gravity (USG), fractional excretion of sodium (FENa), fractional excretion of urea (FEUrea), urine osmolality (UOsm), urine to plasma creatinine ratio (UCr/PCr) and renal failure index (RFI). Overall, 431 patients were included. UNa, UOsm, USG and RFI showed high specificity > 85% for prerenal AKI, UNa and RFI provided good specificity for ATN. Loop diuretics, ACE inhibitors/AT1 blockers or pre-existing chronic kidney disease had no impact. In patients with AKI, UNa, USG and RFI: (1) proved to be very specific for prerenal AKI and showed high sensitivity for ATN; (2) can be easily determined using serum and spot urine; and (3) are not confounded by medication or comorbidities. These parameters/indices are helpful to identify the aetiology of AKI and to guide therapy, thereby improving patients' safety and outcome.

Urine sodium to urine creatinine ratio as a marker of total body sodium in infants with intestinal failure

PURPOSE

Urine sodium (UNa) is a measure of total body sodium in infants with intestinal failure (IF) but can be misleading as it does not reflect volume status. Urine sodium to urine creatinine ratio (UNa:UCr) may offer a more accurate measure, but is not routinely used. This study compares UNa:UCr to UNa as a maker of sodium status in infants with IF.

METHODS

A retrospective review of infants with IF, from a single center, from 2018 to 2020 was conducted (REB H20-00,816). IF etiology, intestinal anatomy, nutritional intake, urine electrolytes and anthropometrics were collected. Linear mixed effects models adjusting for repeated measures were used to associate UNa and UNa:UCr with weight gain and sodium intake.

RESULTS

Twenty-two infants with a median gestational age of 31 weeks were included. IF etiology included gastroschisis (41%), necrotizing enterocolitis (23%), and intestinal perforation (14%). Infants had an average of 3 paired UNa and UNa:UCr measures for a total of 74 paired measurements. UNa:UCr more strongly correlated with sodium intake compared to UNa (R = 0.25, p = 0.032 vs. R = 0.10, p = 0.38). Overall, neither UNa (p = 0.21) nor UNa:UCr (p = 0.16) were significantly correlated with weight gain. However, for infants receiving ≤50% nutrition enterally, weight gain correlated with UNa (p = 0.01) and UNa:UCr (p = 0.01). UNa:UCr >35 predicted adequate growth regardless of enteral intake (92% sensitivity, 59% specificity).

CONCLUSION

UNa:UCr is a measure of total body sodium that correlates with sodium intake in infants with IF. Our study indicates UNa:UCr >35 is associated with adequate growth and can be used to guide further validation studies.

At-home determination of 24-h urine sodium excretion: Validation of chloride test strips and multiple spot samples

Sodium intake and compliance with dietary sodium modification are typically assessed using a 24-h urine collection analyzed using flame photometry, but this is inconvenient. Spot urine samples have been investigated as alternatives to 24-h collections, but their accuracy is poor. Since sodium and chloride are present in equal concentrations in dietary salt, chloride test strips may provide a suitable proxy for at-home measurement of urine sodium concentrations. We aimed to determine whether (i) chloride test strips provide a reliable measure of urinary sodium compared to the gold standard flame photometry and (ii) multiple spot samples accurately reflect 24-h urine sodium. We recruited 43 participants (19 males) aged 23.6 ± 0.6 years to complete multiple consecutive spot samples (morning and evening) along with a 24-h urine sodium collection. Urine 24-h sodium estimates using chloride test strips (114.6 ± 7.5 mmol/day) were highly correlated (r = 0.900, p < 0.0001) with flame photometry (121.1 ± 7.7 mmol/day) with a bias of -6.53 ± 22.2 mmol/day. Use of a three-spot sample average (both morning and evening spot samples) with a correction factor applied (122.9 ± 4.1 mmol/day) provided a good approximation of 24-h sodium measured by flame photometry (125.6 ± 9.0 mmol/day), with a bias of -2.55 ± 43.9 mmol/day. Chloride test strips applied to a 24-h urine collection provide a highly accurate measure of urinary sodium excretion, permitting convenient at-home sample collection and analysis. Their application to multiple spot samples provides a reasonable approximation of sodium excretion that can be used to conveniently monitor attempts at dietary sodium manipulation, without the inconvenience of completing a 24-h urine sample.

Impact of urine osmolality/urine sodium on the timing of diuretic phase and non-invasive ventilation support: Differences from late preterm to term neonates

BACKGROUND

Extracellular fluid retained in the lungs lead to respiratory distress in both late preterm (LP) and term neonates. The relationship between urine parameters toward the diuresis and the duration of ventilation postnatally is unknown. To find the correlation between the diuretic phase with urine parameters in the first 4 days after birth and the duration of non-invasive ventilation (NIV).

METHODS

Serial measurements of urine osmolality (Uosm), urine sodium (U_Na), and urine output (U/O) in neonates were collected at 5 time periods (T1:0-12 postnatal hours, T2:12-24 postnatal hours, T3:24-48 postnatal hours, T4:48-72 postnatal hours, T5:72-96 postnatal hours) were recorded. The correlations were analyzed in late preterm and term neonates.

RESULTS

Ninety-seven neonates were included. Negative correlation between Uosm and U/O were observed. LP neonates (n=26) and term neonates (n=71) had differences with Uosm at T2, U_Na at T4, T5, and U/O at T2, T3. Factors of U/O < 1 ml/kg/hr at T1 (odds ratio (OR) = 20.0; 95% confidence interval (CI) 1.796-222.776; p = 0.015) or Uosm > 273 mOsm/L at T1 (OR = 9.0; 95% CI 1.031-78.574; p = 0.047) in LP neonates and U_Na > 26.5 mEq/L at T5 (OR = 23.625; 95% CI 2.683-79.276; p < 0.01) in term neonates were associated with prolonged NIV use (> 120 hours).

CONCLUSION

We speculate the significant correlation between Uosm/U_Na and the diuretic phase. The LP neonates acquire earlier diuretic phase than the term neonates. The Uosm/U_Na in the first few postnatal days had the correlation with the duration of NIV support.

Serial assessment of spot urine sodium predicts effectiveness of decongestion and outcome in patients with acute heart failure

AIMS

The clinical significance of the measurement of urine sodium concentration (UNa⁺ ) in response to loop diuretic administration in patients with acute heart failure (AHF) is still unsettled. We studied the association of serial measurements of spot UNa⁺ during the first 48 h of AHF treatment with the indices of decongestion, renal function, and prognosis.

METHODS AND RESULTS

We enrolled 111 AHF patients, all of whom received intravenous furosemide on admission. The mean spot UNa⁺ significantly increased in the 6 h sample (P < 0.05 vs. baseline) and returned to baseline values in the 24 and 48 h samples. Based on the increase or decrease/no change of UNa⁺ in the 6 and 48 h samples vs. baseline, patients were divided into two groups at each time point, respectively. Patients did not differ in baseline clinical and laboratory characteristics. Patients with a decrease/no change of UNa⁺ in the 6 and 48 h samples had a lower weight loss during hospitalization. Patients with a decrease/no change of UNa⁺ in the 48 h sample had a poorer diuretic response and a significant increase in the urinary levels of the tubular biomarkers: kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin. Low UNa⁺ and decrease/no change in UNa⁺ in the 6 and 48 h samples were independent predictors of higher risk of all-cause mortality during 1-year follow-up (all P < 0.05).

CONCLUSION

In AHF, low spot UNa+ and lack to increase UNa⁺ in response to intravenous diuretics are associated with poor diuretic response, markers of tubular injury and high risk of 1-year mortality.

The relationship between diabetic risk factors, diabetic complications and salt intake

The relationship between salt and hypertension is the focus of a large amount of research, there are few reviews of the relationship between salt and diabetes, despite the increasing incidence of diabetes. By searching PubMed and the Cochrane Library, we summarized the relationships between diabetic risk factors, diabetic complications and salt intake. The pathophysiological mechanisms underlying the effects of salt on diabetes risk factors and diabetic complications are also discussed. Our findings should assist experts and scholars to understand the current research of salt intake and to pay more attention to the prevention and treatment of related diseases caused by excessive salt intake; guide treatment for patients with diabetes mellitus; and provide a reference for government departments to formulate a reasonable salt restriction policy. We also recommend future research directions.

Cerebral Salt-Wasting Syndrome: Diagnosis by Urine Sodium Excretion

BACKGROUND

Cerebral salt-wasting syndrome (CSWS) was initially described over 60 years ago in hyponatremic patients with a cerebral lesion. However, the diagnostic criteria for CSWS have not been fully established. Thus, when hyponatremia is observed in patients with CSWS, they may be misdiagnosed as having the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Thus, it is critical to differentiate between these 2 conditions because their treatments are diametrically opposed.

MATERIALS AND METHODS

We carried out a retrospective study of 45 patients with CSWS and compared them to 60 normonatremic control patients, and 28 patients with SIADH. All patients had their 24-hour urine volumes and sodium (Na) excretion measured.

RESULTS

In patients with CSWS, urinary Na excretion was 394 ± 369mmol/24 hours and urinary volume was 2,603 ± 996mL/24 hours; both values significantly greater than in controls (P < 0.01). By contrast, in patients with SIADH, the urine Na excretion was only 51 ± 25mmol/24 hours and urine volume was 745 ± 298mL/24 hours; values significantly lower than in patients with CSWS (P < 0.01).

CONCLUSIONS

CSWS was diagnosed in patients with cerebral lesion who had (1) symptomatic hyponatremia, (2) urine Na excretion 2 standard deviations above controls and (3) increased urine volume. Patients with SIADH also had symptomatic hyponatremia but, in contrast to patients with CSWS, they had decreased Na excretion and urine volume. Thus urine Na excretion and volume are very important for diagnosing the cause of hyponatremia in patients with cerebral lesions.

Blood pressure and urolithiasis in children

INTRODUCTION

Urolithiasis is a condition that is most commonly found in adults, but is becoming increasingly prevalent in children. Little is known about the relationship between blood pressure (BP) and urolithiasis in children.

OBJECTIVES

The aim was to evaluate the relationship between urolithiasis and BP, and to determine the association of BP with 24-h urine parameters in children.

METHODS

We retrospectively analyzed BP and 24-h urine data from children <18 years with and without urolithiasis from 2004 to 2015 at a single tertiary center. Children with a diagnosis of non-glomerular hematuria without history of urolithiasis were chosen as the control group. Non-stone formers were excluded if they presented with any abnormal 24-h urine data or kidney disease. Casual BP, BP index (BPi), and 24-h urine parameters were compared between groups using t-tests. Multiple regression analyses adjusting for age, sex and body mass index (BMI) z-score evaluated the association of BP with urolithiasis and urine electrolytes.

RESULTS

The urolithiasis group (N = 71) was significantly older, taller and heavier than the non-stone former group (N = 53) (Table). Systolic BP and diastolic BP in stone formers were significantly greater than in non-stone formers, respectively (p = 0.019). Additionally, systolic BPi was significantly higher in the urolithiasis group (p = 0.03) but there was no significant difference in diastolic BPi (p = 0.45). Urolithiasis was a significant predictor of systolic BPi in the adjusted model (β = 0.04, 95% CI 0.001-0.07). In stone formers, systolic BP and systolic BPi were directly associated with 24-h urine sodium, oxalate/1.73 m², and uric acid (all p < 0.05). Urine calcium was not associated with any BP parameter.

DISCUSSION

The findings are consistent with previous studies in adults that examined the correlation between blood pressure and kidney stones. The results of this study also showed that blood pressure was positively associated with urine sodium, oxalate, and uric acid. Interestingly, contrary to adult literature, our hypothesis which postulated that blood pressure would be associated with an increase in urine calcium was not supported by our findings. The small sample size is a study limitation and the use of healthy controls as a comparison would have been ideal.

CONCLUSIONS

Blood pressure was directly associated with urolithiasis children. Greater BP values were also associated with abnormalities in 24-h urine oxalate, uric acid, and sodium values. Interestingly, BP was not associated with urine calcium in this population.