Pharmacologic Approaches to Electrolyte Abnormalities in Heart Failure

The association of albumin-corrected anion gap and acute kidney injury in heart failure patients: a competing risk model analysis

BACKGROUND

The combination of heart failure (HF) and acute kidney injury (AKI) increases the mortality of patients. It is critical to identify HF patients who may have a high risk for AKI. Albumin-corrected anion gap (ACAG) is a new indicator, but there are no studies on ACAG and the risk of AKI in HF patients.

METHODS

Data for HF patients was obtained from the MIMIC-IV database. Receiver operating characteristic (ROC) analysis and decision curve analysis (DCA) were employed to evaluate the clinical value of ACAG in predicting AKI risk. Logistic regression analysis and restricted cubic spline (RCS) curve were conducted to explore the relationship between ACAG and AKI. A competing risk model was developed to further investigate the relationship between ACAG on AKI.

RESULTS

The study analyzed 5,972 HF patients, with 49.82% (2886/5972) suffering from AKI. The prediction performance of ACAG on AKI was good (AUC:0.656). Continuous ACAG was associated with AKI after adjusting for various significant variables (Model 1: OR = 1.094, 95%CI: 1.078-1.110; Model 2: OR = 1.150, 95%CI: 1.133-1.166; Model 3: OR = 1.035, 95%CI. 1.017-1.054). All High ACAG groups showed a higher risk of AKI (all P < 0.001). ACAG was also linked to in-hospital mortality (P < 0.001). The competing risks model revealed that high ACAG was still a risk factor for AKI when in-hospital mortality served as a competing risk event (P < 0.001).

CONCLUSION

High ACAG was associated with the risk of AKI in HF patients. Clinicians can risk-stratify HF patients by combining ACAG levels.

Targeting Sodium in Heart Failure

A dominant event determining the course of heart failure (HF) includes the disruption of the delicate sodium (Na+) and water balance leading to (Na+) and water retention and edema formation. Although incomplete decongestion adversely affects outcomes, it is unknown whether interventions directly targeting (Na+), such as strict dietary (Na+) restriction, intravenous hypertonic saline, and diuretics, reverse this effect. As a result, it is imperative to implement (Na+)-targeting interventions in selected HF patients with established congestion on top of quadruple therapy with angiotensin receptor neprilysin inhibitor, β-adrenergic receptor blocker, mineralocorticoid receptor antagonist, and sodium glucose cotransporter 2 inhibitor, which dramatically improves outcomes. The limited effectiveness of (Na+)-targeting treatments may be partly due to the fact that the current metrics of HF severity have a limited capacity of foreseeing and averting episodes of congestion and guiding (Na+)-targeting treatments, which often leads to dysnatremias, adversely affecting outcomes. Recent evidence suggests that spot urinary sodium measurements may be used as a guide to monitor (Na+)-targeting interventions both in chronic and acute HF. Further, the classical (2)-compartment model of (Na+) storage has been displaced by the (3)-compartment model emphasizing the non-osmotic accumulation of (Na+), chiefly in the skin. 23(Na+) magnetic resonance imaging (MRI) enables the accurate and reliable quantification of tissue (Na+). Another promising approach enabling tissue (Na+) monitoring is based on wearable devices employing ion-selective electrodes for electrolyte detection, including (Na+) and (Cl-). Undoubtably, further studies using 23(Na+)-MRI technology and wearable sensors are required to learn more about the clinical significance of tissue (Na+) storage and (Na+)-related mechanisms of morbidity and mortality in HF.

Hyponatraemia-treatment standard 2024

Hyponatraemia is the most common electrolyte disorder in hospital patients associated with increased morbidity, mortality, hospital stay and financial burden. The speed of a correction with 3% sodium chloride as a 100- to 150-ml intravenous bolus or continuous infusion depends on the severity and persistence of the symptoms and needs frequent biochemical monitoring. The rapid intermittent administration of hypertonic saline is preferred for treatment of symptomatic hyponatraemia. In asymptomatic mild hyponatraemia, an adequate solute intake with an initial fluid restriction (FR) of 500 ml/day adjusted according to the serum sodium (sNa) levels is preferred. Almost half of the syndrome of inappropriate antidiuretic hormone (SIADH) patients do not respond to FR as first-line therapy. At present, urea and tolvaptan are considered the most effective second-line therapies in SIADH. However, the evidence for guidance on the choice of second-line therapy of hypotonic hyponatraemia is lacking. Oral urea is considered to be a very effective and safe treatment. Mild and asymptomatic hyponatraemia is treated with adequate solute intake (salt and protein) and initial FR with adjustments based on sNa levels. Specific treatment with vaptans may be considered in either euvolaemic or hypervolaemic patients with high ADH activity. In order to ensure optimal patient outcome, close monitoring and readiness for administration of either hypotonic fluids or desmopressin may be crucial in the decision-making process for specific treatment and eventual overcorrection consequences. According to the guidelines, gradual correction and clinical evaluation is preferable over rapid normalization of sNa towards the laboratory reference ranges.

Prognostic value of hypochloremia on mortality in patients with heart failure: a systematic review and meta-analysis

AIMS

Electrolyte imbalances are common in patients with heart failure. Several studies have shown that a low serum chloride level is associated with adverse outcomes in hospitalized patients with acute heart failure and in outpatients with chronic heart failure. We performed a systematic review and meta-analysis to assess the association of hypochloremia with all-cause mortality in patients with heart failure.

METHODS

Data search was conducted from inception through 1 February 2023, using the following MeSH terms: ('chloride' OR 'hypochloremia') AND 'heart failure'. Studies evaluating the association between serum chloride and all-cause mortality in patients with heart failure were included. The predefined primary outcome was all-cause mortality. Pooled hazard ratios and 95% confidence intervals (CIs) were used as effect estimates and calculated with a random-effects model; fixed-effects model and leave-one-out sensitivity analyses were also performed.

RESULTS

A total of 15 studies, involving 25 848 patients, were included. The prevalence of hypochloremia ranged from 8.6 to 31.5%. Follow-up time ranged from 6 to 67 months. Hypochloremia as a categorical variable was associated with an increased risk of all-cause mortality [hazard ratio 1.56; 95% confidence interval (CI) 1.38-1.75; P  < 0.001]. As a continuous variable, serum chloride was associated with all-cause mortality (hazard ratio per mmol/l decrease in serum chloride: 1.06; 95% CI 1.05-1.07; P  < 0.001). Results were confirmed by using several sensitivity analyses.

CONCLUSION

Hypochloremia exhibits a significant prognostic value in patients with heart failure. Serum chloride can be used as an effective tool for risk stratifying in patients with heart failure.

Impact of hypochloremia as a prognostic factor in patients with heart failure, a retrospective cohort study

BACKGROUND

some studies suggest that hypochloremia is a risk factor in the prognosis of heart failure (HF) in patients with recent decompensation.

MATERIALS AND METHODS

retrospective cohort study of patients discharged due to HF decompensation who began follow-up in a specialized clinic. Two groups are defined: patients with hypochloremia (chloride < 98 mmol/L) and normochloremic patients (chloride > 98 mmol/L) in the initial assessment within the first month after discharge. The rate of intravenous diuretic rescue, emergency department visits, readmission for HF and cardiovascular (CV) death are compared using a Cox proportional hazards model.

RESULTS

165 patients were included (59% women, mean age 85 years), with 60 (36%) having hypochloremia. Both groups were comparable in terms of baseline characteristics, except for female sex, presence of peripheral artery disease, moderate-to-severe liver disease (more prevalent in the hypochloremia group), PROFUND index, and baseline furosemide dose (higher in patients with hypochloremia). The incidence of the primary event was higher in subjects with hypochloremia than in normochloremic subjects (HR: 1.59, 95% CI 0.97-2.62), mainly due to the need for intravenous diuretic rescue (HR: 1.86, 95% CI 1.07-3.24).

CONCLUSIONS

hypochloremia following admission for HF decompensation is associated with a greater need for intravenous diuretic rescue therapy and probably worse overall prognosis across the spectrum of the disease, regardless of left ventricular ejection fraction (LVEF).

The association between serum chloride and mortality in ICU patients with heart failure: The impact of bicarbonate

OBJECTIVE

To assess whether serum chloride predicts risk of death in intensive care unit (ICU) patients with heart failure (HF) and the effect of bicarbonate on the efficacy of serum chloride in predicting risk of death in ICU patients.

METHODS

A total of 9364 HF patients hospitalized in the ICU were enrolled. Patients were divided into hypochloremia (< 96 mEq/L), normal chloride (96-108 mEq/L), and hyperchloremia (> 108 mEq/L) groups. Similarly, we divided the serum bicarbonate level into three groups: low bicarbonate (< 22 mEq/L), medium bicarbonate (22-26 mEq/L), and high bicarbonate (> 26 mEq/L). The outcome of this study was in-hospital mortality. Then, we analyzed the association between abnormal serum chloride and mortality according to the category of serum bicarbonate and assessed the interaction effect. Restricted cubic spline (RCS) was used to show possible nonlinear associations.

RESULTS

In the overall study population, hypochloremia was associated with a higher risk of in-hospital mortality than normal chloride (odds ratio [OR] 1.54, 95% confidence interval [CI] 1.26-1.86, P < 0.001), hyperchloremia was not significantly related to in-hospital mortality (OR 1.00, 95% CI 0.85-1.19, P = 0.962). However, a linear association between serum chloride and in-hospital mortality was found in the low and normal bicarbonate groups (all P for nonlinear >0.05).

CONCLUSIONS

Hypochloremia is associated with in-hospital mortality and longer hospital stay in critically ill patients with HF. In addition, risk of death in the low and medium serum bicarbonate groups decreased with increasing serum chloride level.

Chloride in Heart Failure: The Neglected Electrolyte

The increasing burden of heart failure (HF) and emerging knowledge regarding chloride as a prognostic marker in HF have increased the interest in the pathophysiology and interactions of chloride abnormalities with HF-related factors and treatments. Chloride is among the major electrolytes that play a unique role in fluid homeostasis and is associated with cardiorenal and neurohormonal systems. This review elucidates the role of chloride in the pathophysiology of HF, evaluates the effects of treatment on chloride (eg, diuretic agents cause higher urinary chloride excretion and consequently serum hypochloremia), and discusses recent evidence for the association between chloride levels and mortality.

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.

Chloride in Heart Failure Syndrome: Its Pathophysiologic Role and Therapeutic Implication

Until recently, most studies of heart failure (HF) focused on body fluid dynamics through control of the sodium and water balance in the body. Chloride has remained largely ignored in the medical literature, and in clinical practice, chloride is generally considered as an afterthought to the better-known electrolytes of sodium and potassium. In recent years, however, the important role of chloride in the distribution of body fluid has emerged in the field of HF pathophysiology. Investigation of HF pathophysiology according to the dynamics of serum chloride is rational considering that chloride is an established key electrolyte for tubulo-glomerular feedback in the kidney and a possible regulatory electrolyte for body fluid distribution. The present review provides a historical overview of HF pathophysiology, followed by descriptions of the recent attention to the electrolyte chloride in the cardiovascular field, the known role of chloride in the human body, and recent new findings regarding the role of chloride leading to the proposed ‘chloride theory’ hypothesis in HF pathophysiology. Next, vascular and organ congestion in HF is discussed, and finally, a new classification and potential therapeutic strategy are proposed according to the ‘chloride theory’.

Correction of serum chloride concentration in dogs with congestive heart failure

Background

Hypochloremia associated with congestive heart failure (CHF) in dogs is likely multifactorial. Loop diuretics cause 1:2 sodium [Na⁺]:chloride [Cl⁻] loss, whereas water retention causes a 1:1 [Na⁺]:[Cl⁻] dilution. Mathematical [Cl⁻] correction separates these effects on [Cl⁻].

Hypothesis

We hypothesized that corrected [Cl⁻] (c[Cl⁻]) would not differ from measured [Cl⁻] (m[Cl⁻]) in dogs with controlled CHF because of loop diuretics, and dogs with refractory CHF would have higher c[Cl⁻] than m[Cl⁻], indicating relative water excess.

Animals

Seventy‐one client‐owned dogs with acquired heart disease, without CHF (NO‐CHF), 76 with Stage C CHF and 24 with Stage D CHF.

Methods

Clinicopathological data from a previous study were retrospectively analyzed. Corrected [Cl⁻], m[Cl⁻], and differences were compared among NO‐CHF, Stage C CHF, and Stage D CHF, using the formula: c[Cl⁻] = (mid‐reference range [Na⁺]/measured [Na⁺]) × m[Cl⁻].

Results

Corrected [Cl⁻] and m[Cl⁻] were lower in Stage D vs Stage C and NO‐CHF (all P < .0001). The c[Cl⁻] was higher than m[Cl⁻] in Stage D (P < .0001) but not Stage C or NO‐CHF. Median difference between c[Cl⁻] and m[Cl⁻] was higher for Stage D vs Stage C (P = .0003). No hypochloremic Stage D dogs had normal c[Cl⁻], but 11/24 had [Cl⁻] that was increased by >2 mmol/L.

Conclusions and Clinical Importance

Serum [Cl⁻] increased after mathematical correction in Stage D CHF dogs but not in Stage C and NO‐CHF dogs. Although c[Cl⁻] was higher than m[Cl⁻] in Stage D dogs supportive of relative water excess, hypochloremia persisted, consistent with concurrent loop diuretic effects on electrolytes. Future study correlating c[Cl⁻] to antidiuretic hormone concentrations is warranted.

Proposal for New Classification and Practical Use of Diuretics According to Their Effects on the Serum Chloride Concentration: Rationale Based on the "Chloride Theory"

Currently, diuretic therapy for heart failure (HF) pathophysiology is primarily focused on the sodium and water balance. Over the last several years, however, chloride (Cl) has been recognized to have an important role in HF pathophysiology, as both a prognostic marker and a possible central factor regulating the body fluid status. I recently proposed a unifying hypothesis for HF pathophysiology, called the "chloride theory", during HF worsening and recovery, as follows. Chloride is the key electrolyte for regulating both reabsorption of tubular electrolytes and water in the kidney through the renin-angiotensin-aldosterone system and distributing body fluid in each compartment of the body. As changes between the serum Cl concentration and plasma volume are intimately associated with worsening HF and its recovery after decongestive therapy, modulation of the serum Cl concentration by careful selection and combination of various diuretics and their doses could become an attractive therapeutic option for HF. In this review, I will propose a new classification and practical use of diuretics according to their effects on the serum Cl concentration. Diuretic use according to this classification is expected to be a useful strategy for the treatment of patients with HF.

Effects of low extracellular sodium on proliferation and invasive activity of cancer cells in vitro

PURPOSE

Hyponatremia is the most common electrolyte disorder in hospitalized patients, and its etiopathogenesis is related to an underlying tumor in 14% of cases. Hyponatremia has been associated with a worse outcome in several pathologies, including cancer, in which the leading cause of this electrolyte alteration is the syndrome of inappropriate antidiuresis. The aim of this study was to analyze in vitro the effects of low extracellular [Na⁺] in cancer progression.

MATERIALS AND METHODS

We used a previously validated experimental model of chronic hyponatremia to characterize the effects of low extracellular [Na⁺] in different human cancer cell lines: pancreatic adenocarcinoma (PANC-1), neuroblastoma (SK-N-AS, SH-SY5Y), colorectal adenocarcinoma (HCT-8), chronic myeloid leukemia (K562).

RESULTS

Our results demonstrate a direct relationship between low [Na⁺], reduced cell adhesion and increased invasion and proliferation in all cell lines tested. Accordingly, the number of tumor colonies grown in soft agar and the expression of collagenases type IV (metalloproteinases 2 and 9) were markedly higher in cancer cells exposed to reduced extracellular [Na⁺]. Gene analysis showed an upregulation of molecular pathways involved in oxidative stress (heme oxygenase 1) and in proliferation and invasion (RhoA, ROCK-1, ROCK-2). The activation of RhoA/ROCK pathway was paralleled by a deregulation of the cytoskeleton-associated proteins, resulting in the promotion of actin cytoskeletal remodeling and cell invasion.

CONCLUSIONS

Overall, our data demonstrate for the first time that low [Na⁺] promotes cancer progression in vitro, thus suggesting that hyponatremia is not a simple bystander of disease severity in cancer.

Acetazolamide as a potent chloride-regaining diuretic: short- and long-term effects, and its pharmacologic role under the 'chloride theory' for heart failure pathophysiology

According to the "chloride theory" for heart failure (HF) pathophysiology, manipulation of the serum chloride concentration is an important therapeutic target. This study determined the short- and long-term effects of acetazolamide (Diamox), a potential chloride-regaining diuretic, on peripheral blood, serum electrolytes, and renal function. Effects of low-dose Diamox (250-500 mg/day) were evaluated in 30 HF patients for whom Diamox was added as de-novo/add-on decongestion therapy for acutely worsening HF (n = 18) or as modification therapy for serum hypochloremia in stable HF ( < 100 mEq/L; n = 12). Peripheral hematologic tests were performed at baseline, and at short- ( ≤ 10 days) and long-term ( ~ 60 days) time-points. In all 30 study patients of both groups, the serum chloride concentration increased in the short-term and even further over the long-term. The serum potassium concentration constantly decreased throughout the study period. Both the blood urea nitrogen and serum creatinine concentrations increased in the short-term, but returned to baseline levels over the long-term. Responders to Diamox (n = 13; defined by HF resolution and body weight loss ≥ 1 kg) in the decongestion group exhibited reduced serum b-type natriuretic peptide levels and a markedly increased serum chloride concentration, but the hemoglobin/hematocrit and serum creatinine concentrations did not change after treatment. In conclusion, acetazolamide is a potent candidate "chloride-regaining diuretic" for treating HF patients under the "chloride theory". Its effect to enhance the serum chloride concentration occurred within 10 days and persisted for at least ~ 60 days. Plasma volume and renal function were preserved under adequate diuretic treatment with acetazolamide.

Dynamic changes in serum chloride concentrations during worsening of heart failure and its recovery following conventional diuretic therapy: A single-center study

BACKGROUND AND AIMS

Few data are available regarding the dynamic changes in the serum chloride concentrations in heart failure (HF) pathophysiology. The aim of the present study was to investigate changes in the serum chloride concentration under worsening HF and its recovery following conventional diuretic therapy.

METHODS

Blood test data, including measurements of serum albumin/solutes and b-type natriuretic peptide, at both worsening and recovery of HF status, were obtained from 47 patients with definite HF.

RESULTS

Ambulatory patients with HF were enrolled and followed up at the outpatient clinic of Nishida Hospital between June 2003 and March 2009. From clinically stable to worsening HF, the serum sodium concentration increased from (mean ± SD) 139 ± 4.1 to 141 ± 5.07 mEq/L (P < 0.05, two-way analysis of variance) and the serum chloride concentration increased from 101 ± 5.36 to 104 ± 5.44 mEq/L (P < 0.01) among all patients. After resolution of worsening HF by treatment with conventional diuretics, both the serum sodium concentration and serum chloride concentration decreased significantly to 138 ± 5.12 and 99.5 ± 5.33 mEq/L, respectively (P < 0.0001 for each). The absolute changes in the serum sodium concentration from clinically stable HF to worsening HF appeared to be lesser than those in the serum chloride concentration (1.70 ± 4.34 vs 2.72 ± 6.02 mEq/L, P = 0.079, t test), but this was not statistically significant. Absolute changes in the serum sodium concentration from worsening HF to its recovery following treatment with conventional diuretics were lesser than those in the serum chloride concentration (-2.87 ± 4.38 vs -4.45 ± 5.23 mEq/L, P = 0.0068, t test).

CONCLUSION

Under conventional diuretic therapy, greater changes occur in the serum chloride concentration than in the serum sodium concentration under HF state transitions, suggesting that chloride dynamics might contribute more to HF pathophysiology under such therapeutic circumstance.

Vasopressin antagonist-like effect of acetazolamide in a heart failure patient: a case report

Background

Hyponatraemia is easily corrected by treatment with an oral vasopressin antagonist, but these medications are costly and their use at outpatient clinics is restricted by government-managed insurance in Japan. Acetazolamide could be an alternative diuretic to a vasopressin antagonist.

Case Summary

An 83-year-old dyspnoeic male patient was emergently admitted to the hospital due to decompensated heart failure (HF), hypotension, and hyperkalaemia-associated sinus arrest with a junctional escape rhythm. Urgent treatment with a noradrenaline drip infusion and a beta stimulant adhesive skin patch promptly restored sinus rhythm with conducted normal QRS complex, which resolved the hypotension. Blood tests on admission revealed moderately elevated b-type natriuretic peptide (BNP, 576 pg/mL), hyponatraemia (128 mEq/L), hypochloraemia (95 mEq/L), hyperkalaemia (5.7 mEq/L), and preserved renal function (creatinine, 1.0 mg/dL) under no cardiovascular medications. Immediately after admission, low-dose oral acetazolamide (500 mg/day) and polystyrene sulfonate-Ca jelly (Argamate, 25 g/day for 3 days) were prescribed to correct the decompensated HF status and electrolyte disturbance. Three days later, both the serum sodium and chloride concentrations had recovered to normal levels (136 mEq/L and 104 mEq/L, respectively), and the serum potassium concentration had decreased to 4.5 mEq/L. Two weeks later, the patient’s HF status became stable and the serum BNP concentration returned to normal (55 pg/mL).

Discussion

The present case indicates that the classic diuretic of acetazolamide would have a vasopressin blockade-like effect and could be an alternative diuretic to vasopressin antagonists for some proportion of HF patients with hyponatraemia.

Treatment of hypochloremia with acetazolamide in an advanced heart failure patient and importance of monitoring urinary electrolytes

Chloride was recently recognized to play an important role in the pathophysiology of heart failure (HF). Chloride manipulation, including the use of acetazolamide, may be a requisite therapeutic target in HF treatment. An 87-year-old male patient with advanced HF and hypertrophic cardiomyopathy was admitted to the hospital due to hypochloremia (94 mEq/L) and hyponatremia (134 mEq/L) under diuretic treatment with azosemide, spironolactone, and tolvaptan. On admission, HF-related signs of overhydration were lacking, but B-type natriuretic peptide was moderately elevated. The etiology of the hypochloremia/natremia state was depletion of both electrolytes based on serum analysis and spot urinary concentrations. Immediately after admission, acetazolamide (500 mg/d) was prescribed to correct the hypochloremia in parallel with cessation of the preceding administration of azosemide and spironolactone, and tapering off of the tolvaptan over 7 days. Under treatment, both serum chloride and sodium concentrations recovered to normal (108 mEq/L and 148 mEq/L, respectively), and the serum potassium concentration decreased from 3.9 mEq/L to 2.4 mEq/L. Urinary concentrations of sodium and potassium increased from 18 mEq/L to 31 mEq/L and from 19 mEq/L to 51.5 mEq/L respectively, in concordance with the changes in serum concentrations, but the chloride concentration decreased from 18 mEq/L to 12 mEq/L, opposite the changes in the serum concentration. <Learning objective: The present case confirms that the classic drug acetazolamide, although rarely used now for HF treatment, is a potent "chloride-regaining" or "chloride-retaining diuretic" with concomitant activity to reduce serum potassium. Additionally, this case study highlights the importance of monitoring both serum and urinary electrolyte concentrations to determine the electrolyte disturbance and efficacy of diuretic treatment through analytic evaluation of changes in the serum electrolytes and their tubular reabsorption in the kidney.>.

Hyponatraemia - presentations and management

Hyponatraemia is the most common electrolyte disturbance encountered in clinical practice. It is associated with -significant morbidity and mortality, thus appropriate investigation and treatment is essential. Hyponatraemia presents with a spectrum of clinical presentations ranging from no symptoms to life-threatening neurological sequelae. Hyponatraemia has multiple aetiologies and distinguishing the underlying aetiology facilitates appropriate treatment. This review provides an overview of the presentations and approaches to management of this common clinical condition.

Role of circulating factors in cardiac aging

Worldwide increase in life expectancy is a major contributor to the epidemic of chronic degenerative diseases. Aging, indeed, simultaneously affects multiple organ systems, and it has been hypothesized that systemic alterations in regulators of tissue physiology may regulate this process. Cardiac aging itself is a major risk factor for cardiovascular diseases and, because of the intimate relationship with the brain, may contribute to increase the risk of neurodegenerative disorders. Blood-borne factors may play a major role in this complex and still elusive process. A number of studies, mainly based on the revival of parabiosis, a surgical technique very popular during the 70s of the 20th century to study the effect of a shared circulation in two animals, have indeed shown the potential that humoral factors can control the aging process in different tissues. In this article we review the role of circulating factors in cardiovascular aging. A better understanding of these mechanisms may provide new insights in the aging process and provide novel therapeutic opportunities for chronic age-related disorders.