Clinical Risk Factors for Therapeutic Lithium-Associated Electrocardiographic Changes in Patients With Bipolar Disorder

The Effect of Lithium Treatment on the Cardiovascular System

Lithium is regarded as the gold standard treatment for bipolar disorders. Its use has been approved by the Food and Drug Administration since the 1970s. Lithium levels are easily altered by interactions with other medications or pathophysiologic processes. Therefore, physicians should remain vigilant about its side effects. This review examines the existing evidence on the impact of lithium on the cardiovascular system at both supratherapeutic and therapeutic levels, including its effects on cardiac electrophysiology, coronary artery disease, heart dynamics, and metabolic profile. Lithium typically causes benign electrophysiologic changes, such as sinus bradycardia and T-wave changes, with rare instances of significant arrhythmias requiring pacemaker intervention or hemodialysis. Lithium may offer a protective effect against ischemic heart disease and atherosclerosis, which could benefit bipolar disorder patients. The effects on heart dynamics and metabolic profile are not fully understood, with further research needed to clarify these impacts.

Oral supplementation of inositols effectively recovered lithium-induced cardiac dysfunctions in mice

This study investigates the effects of inositol (INO) supplementation on cardiac changes caused by Li in mice. The study involved 4 groups of C57BL6 mice (n=10 each): (i) mice orally administered with Li2CO3 for 8 weeks, then 4 additional weeks without (Li_group) or (ii) with INO supplementation (Li_INOdelayed_group) (total of 12 weeks); (iii) mice given Li2CO3 and INO supplementation concurrently for 12 weeks (Li+INO_group); (iv) one group left untreated (C-group). The INO was administered as a mixture of myo-inositol and d-chiro-inositol (80:1) in drinking water. The mice were characterised for heart morphology, function, electrical activity, arrhythmogenic susceptibility, and multiorgan histopathology (heart, liver and kidney). Cardiomyocyte size, protein expression of key signalling pathways related to hypertrophy, and transcription levels of ion channel subunits and hypertrophy markers were evaluated in the ventricle tissue. The study found that INO supplementation reduced the Li-induced cardiac adverse effects, including systolic impairment and increased susceptibility to arrhythmias. The positive effect on arrhythmias might be attributed to the restored expression levels of the potassium channel subunit Kv 1.5. Additionally, INO improved cardiomyocyte hypertrophy, possibly by inhibiting the Li-induced activation of the ERK1/2 signalling pathway and by restoring the normal expression level of BNP, and alleviated injury in the liver and kidney. The effect was preventive if INO supplementation was taken concurrently with Li and therapeutic if INO was administered after Li-induced cardiac impairments were established. These results provide new insights into the cardioprotective effect of INO and suggest a potential treatment approach for Li-induced cardiac disease.

Lithium Treatment Induces Cardiac Dysfunction in Mice

Lithium (Li) salts are commonly used as medications for bipolar disorders. In addition to its therapeutic value, Li is also being increasingly used as a battery component in modern electronic devices. Concerns about its toxicity and negative impact on the heart have recently been raised. We investigated the effects of long-term Li treatment on the heart, liver, and kidney in mice. Sixteen C57BL/6J mice were randomly assigned to receive oral administration of Li carbonate (n = 8) or act as a control group (n = 8) for 12 weeks. We evaluated the cardiac electrical activity, morphology and function, and pathways contributing to remodelling. We assessed the multi-organ toxicity using histopathology techniques in the heart, liver, and kidney. Our findings suggest that mice receiving Li had impaired systolic function and ventricular repolarisation and were more susceptible to arrhythmias under adrenergic stimulation. The Li treatment caused an increase in the cardiomyocytes' size, the modulation of the extracellular signal-regulated kinase (ERK) pathway, along with some minor tissue damage. Our findings revealed a cardiotoxic effect of Li at therapeutic dosage, along with some histopathological alterations in the liver and kidney. In addition, our study suggests that our model could be used to test potential treatments for Li-induced cardiotoxicity.