Effects of Reducing L-Carnitine Supplementation on Carnitine Kinetics and Cardiac Function in Hemodialysis Patients: A Multicenter, Single-Blind, Placebo-Controlled, Randomized Clinical Trial

"Exploring benefits of L-carnitine in hemodialysis: promising findings await clinical application"

L-carnitine, a crucial component in the metabolism of fatty acids, has shown promise as a treatment for malnutrition and cardiovascular disease in hemodialysis patients. The 2025 meta-analysis by Nabi et al., which documented a statistically significant improvement in left-ventricular ejection fraction (LVEF) after L-carnitine supplementation, is the focus of this letter's evaluation of previous data. Although there has been a noticeable increase in systolic performance, there are still conflicting data on diastolic function and left-ventricular mass index (LVMI). Furthermore, it is becoming more widely acknowledged that L-carnitine deficit contributes to malnutrition in patients on maintenance hemodialysis. This highlights the need for thorough, high-quality clinical trials to confirm the therapeutic efficacy of L-carnitine and evaluate its influence on long-term clinical outcomes.

Safety and efficacy of L-carnitine supplementation in improving cardiac function of hemodialysis patients: a systematic review and meta-analysis

PURPOSE

Heart failure is a significant complication among patients undergoing hemodialysis, often associated with left ventricular hypertrophy and dysfunction. L-carnitine, crucial for fatty acid metabolism, has shown promise in improving cardiac function. This systematic review and meta-analysis aim to evaluate the safety and efficacy of L-carnitine supplementation in improving cardiac function in hemodialysis patients.

METHODOLOGY

A comprehensive search of PubMed, Cochrane, and EMBASE was conducted up to October 3, 2024, to identify relevant studies. The trials assessing the effects of L-carnitine on echocardiographic parameters such as left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), and diastolic function were included. A random-effects model was applied to pool data, and heterogeneity was assessed using the I2 statistic.

RESULTS

A total of 23 studies were included in the systematic review, with 7 studies involving 426 participants being meta-analyzed. L-carnitine supplementation significantly improved LVEF (MD = 1.64, 95% CI 0.10-3.17, p = 0.04), with low heterogeneity (I2 = 37%). However, no significant changes were observed for LVMI (MD = -3.19, p = 0.60) or diastolic markers (E/A ratio MD = -0.13, p = 0.47; E/e ratio MD = -0.35, p = 0.67).

CONCLUSION

L-carnitine supplementation significantly improves cardiac function, particularly systolic function (LVEF) in hemodialysis patients. However, its effects on LVMI and markers of diastolic function are inconclusive. Future large-scale trials are warranted to further elucidate its role in cardiac function among this population.

The impacts of dietary antioxidants on cardiovascular events in hemodialysis patients: An update on the cellular and molecular mechanisms

Cardiovascular-related complications (CVCs) are the primary cause of death in patients undergoing hemodialysis (HD), accounting for greater than half of all deaths. Beyond traditional risk factors, chronic inflammation, extreme oxidative stress (OS), and endothelial dysfunction emerge as major contributors to accelerated CVCs in HD patients. Ample evidence shows that HD patients are constantly exposed to excessive OS, due to uremic toxins and pro-oxidant molecules that overwhelm the defense antioxidant mechanisms. The present study highlights the efficiency of natural antioxidant supplementation in managing HD-induced inflammation, OS, and consequently CVCs. Moreover, it discusses the underlying molecular mechanisms by which these antioxidants can decrease mitochondrial and endothelial dysfunction and ameliorate CVCs in HD patients. Given the complex nature of OS and its molecular pathways, the utilization of specific antioxidants as a polypharmacotherapy may be necessary for targeting each dysregulated signaling pathway and reducing the burden of CVCs.

Effects of L-carnitine supplementation on lipid profile in adult patients under hemodialysis: a systematic review and meta-analysis of RCTs

Background

Chronic kidney disease (CKD) affects 10% of the global population and leads to end-stage renal disease (ESRD). Hemodialysis is a common treatment for ESRD, but patients often have low carnitine levels, leading to dyslipidemia, a risk factor for cardiovascular disease and the leading cause of mortality. This study aimed to assess the effects of L-carnitine on lipid profiles in adult hemodialysis patients.

Methods

A comprehensive search was conducted across the online databases from inception to June 2024 to identify randomized clinical trials (RCTs) evaluating the effects of L-carnitine on lipid profiles in hemodialysis patients. Data extraction and quality assessment were performed, focusing on primary outcomes, including changes in triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL), and secondary outcomes including blood pressure (BP) and body mass index (BMI).

Results

A total of 28 RCTs were eligible for the current systematic review, including 1,340 hemodialysis patients (671 intervention, 669 control). There were no significant differences in the mean change of TG (SMD: -0.006; 95% CI, -0.272 to 0.259; P = 0.95), TC (SMD: -0.086; 95% CI, -0.253 to -0.079; P = 0.29), HDL (SMD: 0.060; 95% CI, -0.057 to 0.177; P = 0.29), LDL (SMD: -0.075; 95% CI, -0.274 to 0.123; P = 0.43), VLDL (SMD: -0.064; 95% CI, -0.272 to 0.142; P = 0.51), BMI (SMD: -0.025; 95% CI, -0.139 to 0.088; P = 0.56), systolic BP (SMD: 0.055; 95% CI, -0.110 to 0.220; P = 0.43), and diastolic BP (SMD: -0.028; 95% CI, 0.156 to 0.099; P = 0.56). The same insignificant findings were observed after conducting a subgroup analysis based on the route of administration (intravenous vs. Oral).

Conclusion

L-carnitine supplementation does not significantly change and improve the serum lipid profile, including TG, TC, HDL, LDL, and VLDL levels. Additionally, it has no notable effects on BMI, systolic, or diastolic BP.

Multi-omics approach for identification of molecular alterations of QiShenYiQi dripping pills in heart failure with preserved ejection fraction

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine theory believes that qi deficiency and blood stasis are the key pathogenesis of heart failure with preserved ejection fraction (HFpEF). As a representative prescription for replenishing qi and activating blood, QiShenYiQi dripping pills (QSYQ) has been used for treating heart diseases. However, the pharmacological mechanism of QSYQ in improving HFpEF is not well understood.

AIM OF THE STUDY

The objective of the study is to investigate the cardioprotective effect and mechanism of QSYQ in HFpEF using the phenotypic dataset of HFpEF.

MATERIALS AND METHODS

HFpEF mouse models established by feeding mice combined high-fat diet and N^ω-nitro-L-arginine methyl ester drinking water were treated with QSYQ. To reveal causal genes, we performed a multi-omics study, including integrative analysis of transcriptomics, proteomics, and metabolomics data. Moreover, adeno-associated virus (AAV)-based PKG inhibition confirmed that QSYQ mediated myocardial remodeling through PKG.

RESULTS

Computational systems pharmacological analysis based on human transcriptome data for HFpEF showed that QSYQ could potentially treat HFpEF through multiple signaling pathways. Subsequently, integrative analysis of transcriptome and proteome showed alterations in gene expression in HFpEF. QSYQ regulated genes involved in inflammation, energy metabolism, myocardial hypertrophy, myocardial fibrosis, and cGMP-PKG signaling pathway, confirming its function in the pathogenesis of HFpEF. Metabolomics analysis revealed fatty acid metabolism as the main mechanism by which QSYQ regulates HFpEF myocardial energy metabolism. Importantly, we found that the myocardial protective effect of QSYQ on HFpEF mice was attenuated after RNA interference-mediated knock-down of myocardial PKG.

CONCLUSION

This study provides mechanistic insights into the pathogenesis of HFpEF and molecular mechanisms of QSYQ in HFpEF. We also identified the regulatory role of PKG in myocardial stiffness, making it an ideal therapeutic target for myocardial remodeling.

Carnitine supplements for people with chronic kidney disease requiring dialysis

BACKGROUND

Carnitine deficiency is common in patients with chronic kidney disease (CKD) who require dialysis. Several clinical studies have suggested that carnitine supplementation is beneficial for dialysis-related symptoms. However, the clinical effectiveness and potential adverse effects of carnitine supplementation in dialysis patients have not been determined.

OBJECTIVES

This review aimed to evaluate the effectiveness and safety of carnitine supplementation for the treatment of dialysis-related complications in CKD patients requiring dialysis.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 16 August 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs (RCTs in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth, or other predictable methods) that compared carnitine supplements with placebo or standard care in people with CKD requiring dialysis.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted study data and assessed study quality. We used a random-effects model to perform a quantitative synthesis of the data.  We used the I² statistic to measure heterogeneity amongst the studies in each analysis. We indicated summary estimates as a risk ratio (RR) for dichotomous outcomes, mean difference (MD) for continuous outcomes, or standardised mean differences (SMD) if different scales were used, with 95% confidence intervals (CI). We assessed the certainty of the evidence for each of the main outcomes using the GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) approach.

MAIN RESULTS

We included 52 studies (47 parallel RCTs and five cross-over RCTs) (3398 randomised participants). All studies compared L-carnitine with a placebo, other treatment, or no treatment. Standard care was continued as co-interventions in each group. Most studies were judged to have an unclear or high risk of bias. L-carnitine may have little or no effect on the quality of life (QoL) SF-36 physical component score (PCS) (4 studies, 134 participants: SMD 0.57, 95% CI -0.15 to 1.28; I² = 73%; low certainty of evidence), and the total QoL score (Kidney Disease Quality of Life (KDQOL), VAS (general well-being), or PedsQL) (3 studies, 230 participants: SMD -0.02, 95% CI -0.29 to 0.25; I² = 0%; low certainty of evidence). L-carnitine may improve SF-36 mental component score (MCS) (4 studies, 134 participants: SMD 0.70, 95% CI 0.22 to 1.18; I² = 42%; low certainty of evidence). L-carnitine may have little or no effect on fatigue score (2 studies, 353 participants: SMD 0.01, 95% CI -0.20 to 0.23; I² = 0%; low certainty of evidence), adverse events (12 studies, 1041 participants: RR, 1.14, 95% CI 0.86 to 1.51; I² = 0%; low certainty of evidence), muscle cramps (2 studies, 102 participants: RR, 0.44, 95% CI 0.18 to 1.09; I² = 23%; low certainty of evidence), and intradialytic hypotension (3 studies, 128 participants: RR, 0.76, 95% CI 0.34 to 1.69; I² = 0%; low certainty of evidence). L-carnitine may improve haemoglobin levels (26 studies, 1795 participants: MD 0.46 g/dL, 95% CI 0.18 to 0.74; I² = 86%; low certainty of evidence) and haematocrit values (14 studies, 950 participants: MD 1.78%, 95% CI 0.38 to 3.18; I² = 84%; low certainty of evidence).

AUTHORS' CONCLUSIONS

The available evidence does not currently support the use of carnitine supplementation in the treatment of dialysis-related carnitine deficiency. Although carnitine supplementation may slightly improve anaemia-related markers, carnitine supplementation makes little or no difference to adverse events. However, these conclusions are based on limited data and, therefore, should be interpreted with caution.

Molecular Mechanism of Induction of Bone Growth by the C-Type Natriuretic Peptide

The skeletal development process in the body occurs through sequential cellular and molecular processes called endochondral ossification. Endochondral ossification occurs in the growth plate where chondrocytes differentiate from resting, proliferative, hypertrophic to calcified zones. Natriuretic peptides (NPTs) are peptide hormones with multiple functions, including regulation of blood pressure, water-mineral balance, and many metabolic processes. NPTs secreted from the heart activate different tissues and organs, working in a paracrine or autocrine manner. One of the natriuretic peptides, C-type natriuretic peptide-, induces bone growth through several mechanisms. This review will summarize the knowledge, including the newest discoveries, of the mechanism of CNP activation in bone growth.