Hyponatraemia aggravates cardiac susceptibility to ischaemia/reperfusion injury

Associations of serum sodium, potassium and chloride levels with the all-cause and cardiovascular diseases mortality among patients with depression

BACKGROUND

Electrolyte disturbances are relatively common in patients with depression, but they are often overlooked, and the relationship between electrolyte changes and adverse outcomes in depression is not yet clear. This study aims to explore the impact of serum electrolyte levels on the all-cause and cardiovascular disease (CVD) mortality rates in patients with depression.

METHODS

This prospective cohort study included 3127 patients with depression who participated in the National Health and Nutrition Examination Survey (NHANES) from 2005 through 2018. Depression was assessed using the Patient Health Questionnaire (PHQ-9), with a PHQ-9 score ≥10 defined as depression. The data were analyzed from April 1 to July 30, 2024. Multivariable Cox proportional hazards regression model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) between serum sodium, potassium, and chloride levels and the CVD risk and all-cause mortality in patients with depression. Three multivariable models were constructed. We further stratified the analysis by age, gender, hypertension, smoking, alcohol consumption, diabetes, and drinking status. Interaction significance was estimated using P-values for the product terms between serum sodium, potassium, chloride, and stratification factors.

RESULTS

This cohort study included data from 2946 participants in the analysis (mean [SD] age, 50.13 [16.48] years; 1116 men [37.88]); During a median (IQR) follow-up of 7.2 (3.6-10.5) years, 398 deaths were recorded, of which 117 were attributed to CVD.After multivariable adjustment, compared with participants in the first quartile of serum sodium levels, the HRs of CVD mortality were 0.90(95% CI, 0.53-1.53) in the fourth quartile (p for trend = 0.484). The HRs of all-cause mortality were 0.73(95% CI, 0.55-0.99) for the fourth quartile (p for trend = 0.003). A nonlinear association was observed between serum sodium levels and all-cause mortality in patients with depression (p for overall = 0.003, p for nonlinear = 0.047). Compared with participants in the first quartile of serum potassium levels, the HRs of CVD mortality were and 1.58(95% CI, 0.98-2.54) in the fourth quartile (p for trend = 0.050), the HRs of all-cause mortality were 1.52(95% CI, 1.16-1.99) for the fourth quartile (p for trend <0.001). A nonlinear association was observed between serum potassium levels and all-cause (p for overall<0.001, p for nonlinear = 0.005) and CVD (p for nonlinear = 0.003) mortality in patients with depression. Compared with participants in the first quartile of serum chlorine levels, the HRs of CVD mortality were 0.84(95% CI, 0.49-1.46) in the fourth quartile(p for trend = 0.284). The HRs of all-cause mortality were 0.70(95% CI, 0.51-0.95) for the fourth quartile(p for trend <0.001). A nonlinear association was observed between serum chlorine levels and all-cause (p for nonlinear<0.001) and CVD (p for nonlinear<0.001) mortality in patients with depression.

CONCLUSION AND CORRELATIONS

This cohort study found that in patients with depression, higher sodium is significantly correlated with lower all-cause mortality, higher potassium is significantly correlated with higher all-cause and CVD mortality, and higher chloride is significantly correlated with lower all-cause and CVD mortality.

Long-Term Clinical Relevance of Hyponatremia Identified During Acute Phase of Myocardial Infarction

Background/Objectives: Hyponatremia is associated with increased mortality in the general hospital population. We sought to investigate whether hyponatremia affects the long-term survival of patients following a myocardial infarction (MI) in both ST-segment elevation (STEMI) and non-ST elevation (NSTEMI) presentations. Methods: In this study, 862 MI patients who were hospitalized between 2012 and 2017 were retrospectively followed-up within the median time period of 41.9 [28.2-73.5] months. All participants were assigned to a hyponatremic or normonatremic group with hyponatremia defined as a sodium level of less than 135 mEq/L on admission. Results: In the acute phase of an MI, hyponatremia was diagnosed in 31 (3.6%) patients. The patients with hyponatremia were less often male (38.7 vs. 70.4%, p < 0.001), and less frequently had Killip class I (63.3 vs. 80%) but more often had Killip class IV on admission (16.7 vs. 4.2%, p = 0.024) and more often had a history of impaired renal function (32.3 vs. 15.5%, p = 0.013) than those with normonatremia. Hyponatremic patients had higher troponin T levels on admission by 75.1% (p = 0.003), a higher isoenzyme MB of creatine kinase level by 34.4% (p = 0.006), and lower hemoglobin (by 8.5%, p = 0.001) levels as compared to the normonatremia group. Long-term mortality was significantly higher in the patients with hyponatremia versus normonatremia (18 [58.1%] vs. 243 [29.2%], log-rank p < 0.001). This was driven by differences in the NSTEMI population (65 vs. 30.5%, p < 0.001). By a Cox proportional hazard regression analysis, hyponatremia was associated with a higher long-term mortality (hazard ratio [HR] of 2.222, a 95% confidence interval [CI] of 1.309-3.773, and p = 0.003). Conclusions: Hyponatremia rarely identified in acute phase of MI was associated with higher long-term mortality, particularly in the NSTEMI population.

Hyponatremia is associated with malignant brain edema after mechanical thrombectomy in acute ischemic stroke

BACKGROUND

Hyponatremia (< 135 mmol/L) is the most common electrolyte disturbance in patients with stroke. However, few studies have reported the relationship between hyponatremia at admission and outcomes in patients with acute ischemic stroke (AIS) treated with mechanical thrombectomy (MT). This study is aimed to explore the association between hyponatremia and clinical outcomes following MT.

METHODS

A retrospective study was conducted at our center. The primary outcome was postoperative malignant brain edema (MBE). The secondary outcomes included mortality and adverse function at the 90-day follow-up, which were defined as modified Rankin scale scores of 6 and > 2, respectively. Patients were classified into hyponatremia and nonhyponatremia groups based on their serum sodium concentration at admission before drug use. The occurrence of MBE was evaluated via computed tomography after MT, and 90-day outcomes were obtained through in-person interviews at the clinic or via telephone. Multivariate analysis was performed to investigate the associations among postoperative MBE, 90-day mortality, adverse function and hyponatremia.

RESULTS

A total of 342 patients were enrolled into the study, of whom 52 (15.2%) had hyponatremia, 86 (25.1%) developed postoperative MBE, 93 (27.2%) died within 90 days after MT, and 201 (58.8%) had adverse functions at the 90-day follow-up. Multivariate analysis revealed that hyponatremia was significantly associated with postoperative MBE (odds ratio [OR] 3.91, 95% confidence interval [CI] 1.66 - 9.23, p = 0.002), 90-day mortality (OR 5.49, 95% CI 2.48 - 12.14, p < 0.001), and 90-day adverse function (OR 3.25, 95% CI 1.29 - 8.12, p = 0.012). In addition, mediation analysis revealed that postoperative MBE may partially account for the 90-day mortality/adverse function of patients with hyponatremia (regression coefficients changed by 18.6% and 23.9%, respectively).

CONCLUSION

Hyponatremia is an independent predictor of postoperative MBE, 90-day mortality, and adverse function. Correction of hyponatremia may reduce the postoperative MBE to improve the prognosis of patients.

Vascular Calcification Is Accelerated by Hyponatremia and Low Osmolality

BACKGROUND

Hyponatremia, frequently observed in patients with chronic kidney disease, is associated with increased cardiovascular morbidity and mortality. Hyponatremia or low osmolality induces oxidative stress and cell death, both of which accelerate vascular calcification (VC), a critical phenotype in patients with chronic kidney disease. Whether hyponatremia or low osmolality plays a role in the pathogenesis of VC is unknown.

METHODS

Human vascular smooth muscle cells (VSMCs) and mouse aortic rings were cultured in various osmotic conditions and calcifying medium supplemented with high calcium and phosphate. The effects of low osmolality on phenotypic change and oxidative stress in the cultured VSMCs were examined. Microarray analysis was conducted to determine the main signaling pathway of osmolality-related VC. The transcellular sodium and calcium ions flux across the VSMCs were visualized by live imaging. Furthermore, the effect of osmolality on calciprotein particles (CPPs) was investigated. Associations between arterial intimal calcification and hyponatremia or low osmolality were examined by a cross-sectional study using human autopsy specimens obtained in the Hisayama Study.

RESULTS

Low osmolality exacerbated calcification of the ECM (extracellular matrix) of cultured VSMCs and mouse aortic rings. Oxidative stress and osteogenic differentiation of VSMCs were identified as the underlying mechanisms responsible for low osmolality-induced VC. Microarray analysis showed that low osmolality activated the Rac1 (Ras-related C3 botulinum toxin substrate 1)-Akt (protein kinase B) pathway and reduced NCX1 (Na-Ca exchanger 1) expression. Live imaging showed synchronic calcium ion efflux and sodium ion influx via NCX1 when extracellular sodium ion concentrations were increased. An NCX1 inhibitor promoted calcifying media-induced VC by reducing calcium ion efflux. Furthermore, low osmolality accelerated the generation and maturation steps of CPPs. The cross-sectional study of human autopsy specimens showed that hyponatremia and low osmolality were associated with a greater area of arterial intimal calcification.

CONCLUSIONS

Hyponatremia and low osmolality promote VC through multiple cellular processes, including the Rac1-Akt pathway activation.

Hyponatremia is associated with unfavorable outcomes after reperfusion treatment in acute ischemic stroke

BACKGROUND AND PURPOSE

In patients with acute ischemic stroke, hyponatremia (plasma sodium < 136 mmol/L) is common and associated with unfavorable outcomes. However, data are limited for patients who underwent intravenous thrombolysis (IVT) and/or endovascular thrombectomy (EVT). Therefore, our aim was to assess the impact of hyponatremia on postreperfusion outcomes.

METHODS

We analyzed data of consecutive patients who presented with acute ischemic stroke and were treated with IVT and/or EVT at Isala Hospital, the Netherlands, in 2019 and 2020. The primary outcome measure was the adjusted common odds ratio (acOR) for a worse modified Rankin Scale (mRS) score at 3-month follow-up. Secondary outcomes included symptomatic intracranial hemorrhage, in-hospital mortality, infarct core, and penumbra volumes.

RESULTS

Of the 680 patients (median age = 73 years, 49% female, median National Institutes of Health Stroke Scale = 5), 430 patients (63%) were treated with IVT, 120 patients (18%) with EVT, and 130 patients (19%) with both. Ninety-two patients (14%) were hyponatremic on admission. Hyponatremia was associated with a worse mRS score at 3 months (acOR = 1.76, 95% confidence interval [CI] = 1.12-2.76) and in-hospital mortality (aOR = 2.39, 95% CI = 1.23-4.67), but not with symptomatic intracranial hemorrhage (OR = 1.17, 95% CI = 0.39-3.47). Hyponatremia was also associated with a larger core (17.2 mL, 95% CI = 2.9-31.5) and core to penumbra ratio (55.0%, 95% CI = 7.1-102.9).

CONCLUSIONS

Admission hyponatremia in patients with acute ischemic stroke treated with IVT and/or EVT was independently associated with unfavorable postreperfusion outcomes, a larger infarct core, and a larger core to penumbra ratio. Future studies should address whether correction of hyponatremia improves the prognosis.

Hyponatremia and takotsubo syndrome: a review of pathogenetic and clinical implications

Hyponatremia is a common electrolyte abnormality with important prognostic and therapeutic implications. It might exert detrimental effects on various organ systems including the central nervous system (CNS), bone, and heart along with its potential association with poor quality of life. These adverse effects might be largely mediated through a variety of mechanisms including osmotic stress, dysfunctional transmembrane exchangers, and enhanced oxidative stress.Interestingly, hyponatremia might also have an important association with takotsubo syndrome (TTS) that has been universally considered as a reversible form of cardiomyopathy usually emerging in response to various stressors. In this context, severe hyponatremia was previously reported to serve as a direct trigger of TTS evolution largely through its potential impact on CNS and heart. However, pathogenetic and clinical implications of hyponatremia still need to be thoroughly evaluated in patients with TTS. This paper aims to analyze the clinical features of published cases with TTS primarily triggered by hyponatremia and also aims to discuss the association between hyponatremia and TTS from a broader perspective.

A profile of SGLT-2 inhibitors in hyponatremia: The evidence to date

Hyponatremia is the most common electrolyte disorder in clinical practice, which may lead to life-threatening complications. Several lines of evidence suggest that hyponatremia is associated not only with significant increases in length of stay, cost, and financial burden, but also with increased morbidity and mortality. Hyponatremia is also considered to be a negative prognostic factor in patients with heart failure and cancer. Although multiple therapeutic methods are available for treating hyponatremia, most have some limitations, such as poor compliance, rapid correction of serum Na⁺, other negative side effects and high cost. Given these limitations, identifying novel therapies for hyponatremia is essential. Recent clinical studies have shown that SGLT-2 inhibitors (SGLT 2i) significantly increased serum Na⁺ levels and were well tolerated by patients who underwent this treatment. Therefore, oral administration of SGLT 2i appears to be an effective treatment for hyponatremia. This article will briefly review the etiology of hyponatremia and integrated control of sodium within the kidney, current therapies for hyponatremia, potential mechanisms and efficacy of SGLT 2i for hyponatremia, and the benefits in cardiovascular, cancer, and kidney disease by regulating sodium and water balance.

Research Progress of Chinese Medicine in the Treatment of Myocardial Ischemia-Reperfusion Injury

Vascular recanalization is the essential procedure in which severe coronary artery stenosis is diagnosed. However, the blood flow recovery associated with this procedure may cause myocardial ischemia-reperfusion injury (MIRI), which aggravates heart failure. Unfortunately, the mechanism of MIRI has historically been poorly understood. As we now know, calcium overloading, oxidative stress, mitochondrial dysfunction, inflammatory responses, and ferroptosis take part in the process of MIRI. Modern medicine has shown through clinical studies its own limited effects in the case of MIRI, whereas Chinese traditional medicine demonstrates a strong vitality. Multiple-target effects, such as anti-inflammatory, anti-oxidant, and cardio-protection effects, are central to this vitality. In our clinic center, Yixin formula is commonly used in patients with MIRI. This formula contains Astragalus, Ligusticum Wallichii, Salvia, Rhodiola Rosea, Radix Angelicae Sinensis, Cyperus Rotundus, and Cassia Twig. Its effects include warming yang energy, activating blood circulation, and eliminating blood stasis. In our previous laboratory studies, we have proved that it can reduce MIRI and oxidative stress injury in rats suffering from ischemia myocardiopathy. It can also inhibit apoptosis and protect myocardium. In this paper, we review the research of Yixin formula and other related herbal medicines in MIRI therapy.

Hyponatremia and Oxidative Stress

Hyponatremia, i.e., the presence of a serum sodium concentration ([Na+]) < 136 mEq/L, is the most frequent electrolyte imbalance in the elderly and in hospitalized patients. Symptoms of acute hyponatremia, whose main target is the central nervous system, are explained by the "osmotic theory" and the neuronal swelling secondary to decreased extracellular osmolality, which determines cerebral oedema. Following the description of neurological and systemic manifestations even in mild and chronic hyponatremia, in the last decade reduced extracellular [Na+] was associated with detrimental effects on cellular homeostasis independently of hypoosmolality. Most of these alterations appeared to be elicited by oxidative stress. In this review, we focus on the role of oxidative stress on both osmolality-dependent and -independent impairment of cell and tissue functions observed in hyponatremic conditions. Furthermore, basic and clinical research suggested that oxidative stress appears to be a common denominator of the degenerative processes related to aging, cancer progression, and hyponatremia. Of note, low [Na+] is able to exacerbate multiple manifestations of senescence and to decrease progression-free and overall survival in oncologic patients.

Preoperative hyponatremia predicts complications in older patients undergoing digestive tract surgery: a propensity score matching analysis

Aim

This study aimed to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Findings

Preoperative hyponatremia was associated with an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery. Preoperative hyponatremia was also correlated with a higher risk of postoperative infectious complications.

Message

Preoperative hyponatremia can predict the development of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Purpose

Whether preoperative hyponatremia increases the risk of postoperative complications in older patients undergoing digestive tract surgery remains unclear. The purpose of the study was to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Methods

This was a propensity score-matched, retrospective cohort study. We recruited older patients (≥ 65 years of age) who underwent digestive tract surgery in our institution. The propensity score matching (PSM; 1:2) was used to balance a range of covariates between patients with preoperative hyponatremia (serum sodium [Na⁺] levels < 135 mmol/L) and those with normal [Na⁺] levels (135–145 mmol/L). The primary outcome was the occurrence of life-threatening postoperative complications and mortality (i.e., Clavien–Dindo grade IV and V [CD IV and V] complications) during hospital stay. The relationship between preoperative hyponatremia and the development of CD IV and V complications was identified with logistic regression analysis.

Results

A total of 1076 patients were analyzed (mean age 73.9 years; 421 female [39.1%]). Preoperative hyponatremia was identified in 122 patients. After matching, 312 patients were included in the analyses (104 patients with preoperative hyponatremia and 208 patients with normal [Na⁺] levels; mean age, 76.3 years; 130 female [41.7%]). When compared with normal [Na⁺] levels, preoperative hyponatremia was associated with an increased risk of CD IV and V complications (odds ratio [OR] 2.082, 95% confidential interval [CI] 1.041–4.164, P = 0.038). Preoperative hyponatremia was also significantly associated with a higher risk of postoperative infectious complications (OR 2.158, 95% CI 1.138–4.091, P = 0.018).

Conclusion

Preoperative hyponatremia can predict an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Hyponatraemia aggravates cardiac susceptibility to ischaemia/reperfusion injury

Hyponatraemia is defined as a serum sodium concentration of <135 mEql/L and is the most common electrolyte disturbance in patients with chronic heart failure. We hypothesize that hyponatraemia may induce Ca²⁺ overload and enhance reactive oxygen species (ROS) production, which will exacerbate myocardial injury more than normonatraemia. We investigated the effect of hyponatraemia on the ability of the heart to recover from ischaemia/reperfusion episodes. Cardiomyocytes were obtained from 1- to 3-day-old Sprague Dawley rats. After isolation, cardiomyocytes were placed in Dulbecco's modified Eagle's medium (DMEM) containing low sodium concentration (110, 120, or 130 mEq/L) or normal sodium concentration (140 mEq/L) for 72 hours. Exposure of cardiomyocytes to each of the low-sodium medium significantly increased both ROS and intracellular Ca²⁺ levels compared with the exposure to the normal-sodium medium. In vivo, 8-week-old male Sprague Dawley rats were divided into four groups: control group (Con), furosemide group (Fur), low-sodium diet group (Lsd) and both furosemide and low-sodium diet group (Fur + Lsd). The hearts subjected to global ischaemia exhibited considerable decrease in left ventricular developed pressure during reperfusion, and the size of infarcts induced by ischaemia/reperfusion significantly increased in the Fur, Lsd and Fur + Lsd compared with that in the Con. Hyponatraemia aggravates cardiac susceptibility to ischaemia/reperfusion injury by Ca²⁺ overload and increasing in ROS levels.