The effects of L-carnitine supplementation on indicators of inflammation and oxidative stress: a systematic review and meta-analysis of randomized controlled trials

The effects of concurrent alpha-linolenic acid, L-carnitine supplementation on clinical symptoms, mental health, and quality of life in women with migraine: a randomized, triple-blind, placebo-controlled trial

BACKGROUND

Migraine, as a widespread neurological condition, substantially impacts quality of life, particularly among women. Therefore, this study aimed to explore the potential effects of alpha-linolenic acid (ALA) and L-carnitine co-supplementation on migraine symptoms, mental health, and life quality in women with migraine.

METHODS

In this randomized, triple-blind, placebo-controlled trial, 80 women with migraine were randomly assigned to receive either ALA (1000 mg) plus L-carnitine (500 mg) or matching placebos daily for 12 weeks. Migraine characteristics, mental health parameters, and quality of life measures were assessed at baseline and study end.

RESULTS

The intervention group demonstrated a significant reduction in migraine frequency (-2.96; 95% CI (-3.48, -2.45) vs -0.07; 95% CI (-0.68, 0.53), P < 0.001), severity (-1.6; 95% CI (-2.05, -1.15) vs - 0.44; 95% CI (-0.91, 0.02), P = 0.001), and duration (-4.9; 95% CI (-6.34, -3.45) vs -0.5; 95% CI (-1.06, 0.66) hours, P < 0.001) compared to the placebo group. Mental health improvements were observed in depression (-7.4; 95% CI (-9.24, -5.55) vs 0.05; 95% CI (-1.16, 1.26), P < 0.001), and anxiety scores (-5.7; 95% CI (-7.26, -4.14) vs - 0.65; 95% CI (-2.33, 1.03), P < 0.001). Quality of life measures showed significant enhancement, with increased migraine-specific quality of life (9.75; 95% CI (8.01, 11.49) vs 1.22; 95% CI (-0.66, 3.11), P < 0.001) and decreased headache impact test-6 scores (-8.57; 95% CI (-11.79, -5.36) vs -1.35; 95% CI (-3.41, 0.71), P = 0.005) in the intervention group compared to the controls.

CONCLUSION

Co-supplementation with ALA and L-carnitine may offer a promising adjuvant therapy for managing migraine in women, addressing both physical symptoms and psychological burdens.

TRIAL REGISTRATION

IRCT20121216011763N57.

Cytoprotective effect of l-carnitine against mancozeb-induced oxidative damage in human erythrocytes

Mancozeb is a commonly used fungicide that protects crops from numerous fungal pathogens. However, due to its widespread application, mancozeb has emerged as a significant human health hazard. Mancozeb causes oxidative damage to human cells, including erythrocytes. In this study, we have investigated the cytoprotective potential of the dietary antioxidant, l-carnitine, on mancozeb-induced oxidative damage in human erythrocytes. Incubation of erythrocytes with 100 μM mancozeb for 24 h caused a substantial elevation of markers of hemoglobin, lipid and protein oxidation. Intracellular levels of reactive oxygen and nitrogen species were considerably increased, and the antioxidant defense system of erythrocytes was severely compromised. Several enzymes catalyzing vital metabolic processes in erythrocytes were significantly inhibited. Mancozeb damaged the plasma membrane, increasing osmotic fragility and cell lysis. Membrane damage resulted in morphological transformation of the normal biconcave erythrocytes to echinocytes and stomatocytes. Erythrocytes incubated with l-carnitine (100-750 μM) for 2 h prior to mancozeb treatment showed a marked reduction in oxidative damage. l-carnitine effectively neutralized free radicals and reactive species, thereby significantly diminishing oxidative stress. The activities of antioxidant and metabolic enzymes were also restored. Preincubation with l-carnitine stabilized the erythrocyte membrane and maintained its standard biconcave shape. Incubation of erythrocytes with l-carnitine alone did not alter any of the above parameters. Thus, l-carnitine can serve as an effective protectant against pesticide-induced cytotoxicity in human erythrocytes.

Neuroprotective effects of L-carnitine towards oxidative stress and inflammatory processes: a review of its importance as a therapeutic drug in some disorders

L-carnitine (LC) is a natural compound crucial for transporting long-chain fatty acids into mitochondria for ATP production. It is found mainly in red meat, fish, and dairy products, in addition to being synthesized by the body. LC is supplemented in patients with organic acidemias since it corrects secondary carnitine deficiency and accelerates the removal of the accumulated acyl organic acid derivative groups. Recently, it was also shown to behave as an antioxidant and an anti-inflammatory agent in various pathological conditions like hypertension, diabetes, and neurodegenerative diseases. Inflammation is a complex response to tissue damage or infection associated with oxidative stress. LC has been implicated in reducing inflammatory cytokines and other biomarkers. Recent studies suggest that LC supplementation reduces inflammation in chronic kidney disease, cardiovascular disease, and neuroinflammation. LC supplementation has been effective in reducing inflammatory markers like C-reactive protein (CRP) and interleukins (IL-6, TNF-α) in various pathologies, including septic shock and polycystic ovary syndrome (PCOS). It has also been shown to reduce cardiovascular events in patients with end-stage renal disease. In experimental models, LC revealed neuroprotective effects, improving memory and reducing neuronal death. Additionally, in spinal cord ischemia-reperfusion injury and acute myocardial infarction, LC treatment diminished inflammation and oxidative stress while improving neurological and cardiac functions. In conclusion, LC supplementation demonstrates significant potential properties in reducing inflammation and improving health outcomes in various pathological conditions, making it a subject of increasing interest in medical research. This article aims to review the literature on the anti-inflammatory and antioxidant effects of LC in different pathologies.

Modulatory Effects of Multi-species/Multi-strain Synbiotic and L-carnitine Concomitant Supplementation on Atherogenic-Indices, Body Composition, Visceral Obesity, and Appetite in Metabolically Healthy Women with Obesity: A Double-Blind Randomized Controlled Clinical Trial

Obesity, a chronic disease with pandemic proportions, is recognized as a major risk factor for cardiometabolic disorders due to its association with atherogenic dyslipidemia, a common characteristic attributed to visceral adiposity in patients with obesity. Atherogenic and visceral-obesity indices have been conceded as surrogate cardiovascular diseases (CVD) indicators surpassing the conventional markers due to stronger predictive power for obesity-induced cardiometabolic risk and CVD mortality rate. Nutraceuticals have been suggested as emerging approaches to counteract obesity-associated cardiometabolic disorders. Considering the evidence addressing the ameliorating effects of either L-carnitine or biotics on metabolic indices, also the reports addressing higher efficacy of concomitant supplementation versus single-therapies, this clinical trial was conducted to assess the effects of L-carnitine + multi-species/multi-strain synbiotic combined supplementation compared to L-carnitine mono-therapy on atherogenic-indices, body composition, visceral obesity, and appetite sensations in 46 metabolically healthy women with obesity, randomly assigned to co-supplementation (L-carnitine-tartrate (2 × 500 mg/dl) + synbiotic (one capsule/day)) or mono-therapy (L-carnitine-tartrate (2 × 500 mg/dl) + maltodextrin (one capsule/day)) groups for 8 weeks. L-carnitine + synbiotic co-supplementation led to a significantly greater reduction in atherogenic-indices including atherogenic-index-of-plasma (AIP), Castelli's-risk-index-I (CRI-I), Castelli's-risk-index-II (CRI-II), atherogenic-coefficient (AC), lipoprotein-combine index (LCI), systolic blood pressure (SBP), fat-mass (FM) weight/percent, visceral-adiposity index (VAI), waste-to-height ratio (WHtR), body-adiposity index (BAI), and appetite sensation scores compared to L-carnitine mono-therapy. L-carnitine + synbiotic combined supplementation was more efficient in improving atherogenic-indices as cardiovascular risk markers, body composition, visceral obesity, and appetite sensations in metabolically healthy women with obesity. Therefore, simultaneous supplementation of L-carnitine + synbiotic might be considered a promising approach to ameliorate cardiometabolic risk factors in healthy individuals with obesity. Further longer period studies are required to confirm these findings. (Iranian Registry of Clinical Trials (IRCT; https://irct.behdasht.gov.ir/trial/28048 ).

The effect of L-carnitine supplementation on anthropometric and malnutrition status in acute ischemic stroke patients: a triple-blinded randomized clinical trial

BACKGROUND

Malnutrition is a significant challenge in stroke patients, affecting both rehabilitation and independence. This study aims to evaluate whether early L-carnitine supplementation can effectively improve anthropometric parameters and malnutrition status in acute-phase ischemic stroke patients to mitigate the catabolic state.

METHODS

Eighty-two first-ever ischemic stroke patients were randomly assigned to either the L-carnitine group (1000 mg three times/day for seven consecutive days) or the matching placebo group. The study outcomes based on intention-to-treat analyses included changes in weight, body mass index, triceps skinfold thickness, mid-arm circumference, mid-arm muscle circumference, arm muscle area, calf circumference, serum ALB and malnutrition status over the seven-day treatment protocol. Malnutrition was assessed based on the serum ALB concentration, mid-arm muscle circumference, and triceps skinfold thickness. Analysis of covariance (ANCOVA) was applied for assessing the between-group changes along with adjusting the baseline mean value effect.

RESULTS

Patients receiving L-carnitine had significantly lower changes in terms of weight, body mass index, triceps skinfold thickness, mid-arm circumference, mid-arm muscle circumference, and calf circumference than did those in the placebo group. After the intervention, the placebo group experienced a significantly greater reduction in the mid-arm muscle circumference indicator (P < 0.001). The between-group change in the serum ALB concentration significantly increased in the L-carnitine group (P = 0.001). Moreover, the L-carnitine group was less malnourished than the placebo group [17 (41.5%) vs. 30 (73.2%), respectively; P = 0.01], after the intrvention. The "recovery" frequency was significantly greater in the L-carnitine group (18 (43.9%) vs. 3 (7.3%), P < 0.001) than the placebo group.

CONCLUSIONS

Early L-carnitine supplementation effectively improves anthropometric indices and malnutrition, muscle wasting, and rapid weight loss in acute ischemic stroke patients, highlighting its potential as a supportive nutritional therapy during stroke rehabilitation.

TRIAL REGISTRATION

The current clinical trial study was registered in the Iranian Registry of Clinical Trials (registration code: IRCT20221206056734N1) at 2023-02-11.

Neuropsychiatric Manifestations of COVID-19 Disease and Post COVID Syndrome: The Role of N-acetylcysteine and Acetyl-L-carnitine

COVID-19 is associated with neuropsychiatric symptoms, such as anosmia, anxiety, depression, stress-related reactions, and psychoses. The illness can cause persistent cognitive impairment and "brain fog", suggesting chronic brain involvement. Clinical entities of ongoing symptomatic COVID-19 and Post COVID Syndrome (PCS) mainly present neuropsychiatric symptoms such as dysgeusia, headache, fatigue, anxiety, depression, sleep disturbances, and post-traumatic stress disorder. The pathophysiology of COVID-19-related brain damage is unclear, but it is linked to various mechanisms such as inflammation, oxidative stress, immune dysregulation, impaired glutamate homeostasis, glial and glymphatic damage, and hippocampal degeneration. Noteworthy is that the metabotropic receptor mGluR2 was discovered as a mechanism of internalisation of SARS-CoV-2 in Central Nervous System (CNS) cells. N-acetylcysteine (NAC) and acetyl-L-carnitine (ALC) are two supplements that have already been found effective in treating psychiatric conditions. Furthermore, NAC showed evidence in relieving cognitive symptomatology in PCS, and ALC was found effective in treating depressive symptomatology of PCS. The overlapping effects on the glutamatergic system of ALC and NAC could help treat COVID-19 psychiatric symptoms and PCS, acting through different mechanisms on the xc-mGluR2 network, with potentially synergistic effects on chronic pain and neuro-astrocyte protection. This paper aims to summarise the current evidence on the potential therapeutic role of NAC and ALC, providing an overview of the underlying molecular mechanisms and pathophysiology. It proposes a pathophysiological model explaining the effectiveness of NAC and ALC in treating COVID-19-related neuropsychiatric symptoms.

Revisiting the Role of Carnitine in Heart Disease Through the Lens of the Gut Microbiota

L-Carnitine, sourced from red meat, dairy, and endogenous synthesis, plays a vital role in fatty acid metabolism and energy production. While beneficial for cardiovascular, muscular, and neural health, its interaction with the gut microbiota and conversion into trimethylamine (TMA) and trimethylamine N-oxide (TMAO) raise concerns about heart health. TMAO, produced through the gut-microbial metabolism of L-carnitine and subsequent liver oxidation, is associated with cardiovascular risks, including atherosclerosis, heart attacks, and stroke. It contributes to cholesterol deposition, vascular dysfunction, and platelet aggregation. Omnivorous diets, rich in L-carnitine, are associated with higher TMAO levels compared to plant-based diets, which are linked to lower cardiovascular disease risks. Dietary interventions, such as increasing fiber, polyphenols, and probiotics, can modulate the gut microbiota to reduce TMAO production. These strategies seek to balance L-carnitine's benefits with its potential risks related to TMAO production. Future research should focus on personalized approaches to optimize L-carnitine use while mitigating its cardiovascular impacts, exploring microbial modulation and dietary strategies to minimize the TMAO levels and associated risks.

Neurodegenerative biomarkers and inflammation in patients with propionic and methylmalonic acidemias: effect of L-carnitine treatment

Propionic and methylmalonic acidemias (PAcidemia and MMAcidemia, respectively) are genetic disorders characterized by acute metabolic decompensation and neurological complications. L-carnitine (LC) is effective in reducing toxic metabolites that are related to the pathophysiology of these diseases. Therefore we investigated biomarkers of inflammation (cytokines and C-reactive protein (CRP)), neurodegeneration (BDNF, NCAM-1 and cathepsin-D) and biomolecules oxidation (sulfhydryl content and thiobarbituric acid-reactive species (TBARS)), as well as carnitine concentrations in untreated patients with PAcidemia and MMAcidemia, in patients under treatment with LC and a protein-restricted diet for until 2 years and in patients under the same treatment for more than 2 years. It was verified an increase of CRP, IL-6, IL-8, TNF-α, IL-10, NCAM-1 and cathepsin-D in untreated patients compared to controls. On the other hand, reduced levels of TNF-α, CRP, IL-10, NCAM-1 and cathepsin-D were found in plasma from treated patients, as well as increased concentrations of LC. Furthermore, oxidative biomarkers were increased in untreated patients and were normalized with the prolonged treatment with LC. In conclusion, this work shows, for the first time, that inflammatory and neurodegenerative peripheral biomarkers are increased in patients with PAcidemia and MMAcidemia and that treatment with LC is effective to protect against these alterations.

Metabolomic comparison of postprandial distress syndrome patients with and without duodenal eosinophilia

OBJECTIVE

In functional dyspepsia patients, duodenal mucosal eosinophilia has been associated with early satiety but is not present in all patients suggesting varied pathways to symptom generation. The objective of the current study was to explore metabolic differences comparing those with duodenal mucosal eosinophilia to those without eosinophilia.

METHODS

This study was conducted utilizing an existing biorepository. Patients had plasma samples obtained at the time of endoscopy. All had undergone endoscopy for dyspepsia and reported early satiety. Two groups were identified including those with peak duodenal mucosal eosinophil densities above 30/high power field (N = 28) and those below 30 (N = 16). The fasting plasma samples were analyzed by liquid chromatography/high-resolution mass spectrometry. Significant differences between groups were determined.

RESULTS

The eosinophilia group demonstrated significant elevations in several gamma-glutamyl amino acids. The eosinophilia group had elevations of metabolites associated with oxidative stress including glutathione metabolites (cysteinlyglycine and cys-gly oxidized), and metabolites related to nitric oxide synthesis (arginine, citrulline, ornithine, and dimethylarginine). Eosinophilia was also associated with alterations in lipid metabolism including several long-chain acylcarnitine conjugated fatty acids. Carnitine levels were lower in the eosinophilia group. Lastly, vanillymandelate, a derivative of norepinephrine and epinephrine was elevated in the eosinophilia group.

CONCLUSIONS

In patients with dyspepsia and early satiety, duodenal mucosal eosinophilia is associated with metabolites levels which are consistent with increased oxidative stress and alterations in lipid metabolism. Eosinophilia was also associated with lower carnitine levels. These alterations may contribute to pathophysiology and represent therapeutic targets.

The effects of L-carnitine supplementation on cardiovascular risk factors in participants with impaired glucose tolerance and diabetes: a systematic review and dose-response meta-analysis

AIMS

L-carnitine plays a role related to cardiometabolic factors, but its effectiveness and safety in CVD are still unknown. We aim to assess the effect of L-carnitine supplementation on CVD risk factors.

METHODS

A systematic literature search was conducted in PubMed, Web of Science, and Scopus until October 2022. The main outcomes were lipid profiles, anthropometric parameters, insulin resistance, serum glucose levels, leptin, blood pressure, and inflammatory markers. The pooled weighted mean difference (WMD) was calculated using a random-effects model.

RESULTS

We included the 21 RCTs (n = 2900) with 21 effect sizes in this study. L-carnitine supplementation had a significant effect on TG (WMD = - 13.50 mg/dl, p = 0.039), LDL (WMD = - 12.66 mg/dl, p < 0.001), FBG (WMD = - 6.24 mg/dl, p = 0.001), HbA1c (WMD = -0.37%, p = 0.013) HOMA-IR (WMD = -0.72, p = 0.038 (, CRP (WMD = - 0.07 mg/dl, P = 0.037), TNF-α (WMD = - 1.39 pg/ml, p = 0.033), weight (WMD = - 1.58 kg, p = 0.001 (, BMI (WMD = - 0.28 kg/m2, p = 0.017(, BFP (WMD = - 1.83, p < 0.001) and leptin (WMD = - 2.21 ng/ml, p = 0.003 (in intervention, compared to the placebo group, in the pooled analysis.

CONCLUSIONS

This meta-analysis demonstrated that administration of L-carnitine in diabetic and glucose intolerance patients can significantly reduce TG, LDL-C, FBG, HbA1c, HOMA-IR, CRP, TNF-α, weight, BMI, BFP, and leptin levels. PROSPERO registration code: CRD42022366992.

L-Carnitine Ameliorates Amiodarone-Mediated Alveolar Damage: Oxidative Stress Parameters, Inflammatory Markers, Histological and Ultrastructural Insights

The aim of this study was to assess L-carnitine's effects on adult male rats' lung damage brought on by amiodarone, which is a potent antiarrhythmic with limited clinical efficacy due to potentially life-threatening amiodarone-induced lung damage. Because of the resemblance among the structural abnormalities in rats' lungs that follows amiodarone medication and pulmonary toxicity in human beings, this animal model may be an appropriate example for this disease entity. Amiodarone produced pulmonary toxicity in twenty-four healthy male albino rats (150-180 g) over a period of 6 weeks. Four groups of six rats each were established: control, sham, amiodarone, and L-carnitine plus amiodarone. Histological, ultrastructural, oxidative stress, and inflammatory markers were determined during a 6-week exposure experiment. Amiodarone-induced lung damage in rats may be brought on due to oxidative stress producing significant pulmonary cytotoxicity, as evidenced by the disruption of the mitochondrial structure, severe fibrosis, and inflammatory response of the lung tissue. Lungs already exposed to such harmful effects may be partially protected by the antioxidant L-carnitine. Biochemical markers of lung damage brought on by amiodarone include lung tissue levels of the enzyme's catalase, superoxide dismutase, and reduced glutathione. The levels of lipid peroxides in lung tissue measured as malondialdehyde increased significantly upon exposure to amiodarone. In addition, the levels of tumor necrosis factor alpha were significantly elevated in response to amiodarone. The effect of L-carnitine on amiodarone-induced pulmonary toxicity was studied in rats. It is interesting to note that the intake of L-carnitine in rats treated with amiodarone partially restored the biochemical and histopathological alterations brought on by amiodarone to their original levels. Tumor necrosis factor alpha levels were significantly reduced upon L-carnitine exposure. These results suggest that L-carnitine can be used to treat amiodarone-induced pulmonary dysfunction.

Influence of Amino Acids and Exercise on Muscle Protein Turnover, Particularly in Cancer Cachexia

Cancer cachexia is a multifaceted syndrome that impacts individuals with advanced cancer. It causes numerous pathological changes in cancer patients, such as inflammation and metabolic dysfunction, which further diminish their quality of life. Unfortunately, cancer cachexia also increases the risk of mortality in affected individuals, making it an important area of focus for cancer research and treatment. Several potential nutritional therapies are being tested in preclinical and clinical models for their efficacy in improving muscle metabolism in cancer patients. Despite promising results, no special nutritional therapies have yet been validated in clinical practice. Multiple studies provide evidence of the benefits of increasing muscle protein synthesis through an increased intake of amino acids or protein. There is also increasing evidence that exercise can reduce muscle atrophy by modulating protein synthesis. Therefore, the combination of protein intake and exercise may be more effective in improving cancer cachexia. This review provides an overview of the preclinical and clinical approaches for the use of amino acids with and without exercise therapy to improve muscle metabolism in cachexia.

The Effects of L-Carnitine Supplementation on Weight Loss, Glycemic Control, and Cardiovascular Risk Factors in Patients With Type 2 Diabetes: A Systematic Review and Dose-response Meta-Analysis of Randomized Controlled Trials

PURPOSE

L-carnitine supplementation has been recommended to improve cardiometabolic health markers in diabetic patients. Our purpose was to assess the dose-dependent effects of l-carnitine supplementation on cardiometabolic risk factors in patients with type 2 diabetes.

METHODS

PubMed/Medline, Scopus, and Web of Science were searched until May 2022 for randomized controlled trials that examined the impact of l-carnitine supplementation on cardiometabolic risk factors in adults with type 2 diabetes. The mean difference (MD) and its 95% confidence interval (CI) were estimated utilizing a random-effects model. Nonlinear dose-response associations were modeled with restricted cubic splines. The certainty of evidence was rated using the GRADE approach.

FINDINGS

Twenty-one randomized trials with 2041 patients with type 2 diabetes were included. We found that every 1 g/d supplementation with l-carnitine significantly reduced body mass index (MD: -0.37 kg/m2, 95% CI: -0.59, -0.15; I2 =93%, n=13, GRADE=low), HbA1c (MD: -0.16%, 95% CI: -0.32, -0.01; I2 = 94%, n = 18, GRADE = moderate), and low-density lipoprotein cholesterol (MD: -0.11 mmol/L, 95% CI: -0.16, -0.05; I2 = 91%, n = 11, GRADE = high). There were also reductions in serum triglycerides (MD: 0.07 mmol/L), total cholesterol (MD: -0.13 mmol/L), and fasting plasma glucose (MD: -0.17 mmol/L). A U-shaped effect was demonstrated for body mass index, with the largest reduction at 2 g/d. A linear reduction was seen for serum triglycerides, total cholesterol, and fasting plasma glucose up to l-carnitine supplementation of 4 g/d.

IMPLICATIONS

L-carnitine supplementation resulted in a small reduction in serum lipids and plasma glucose in patients with type 2 diabetes. However, due to high statistical heterogeneity, the results should be interpreted very cautiously.

L-Carnitine in the Treatment of Psychiatric and Neurological Manifestations: A Systematic Review

OBJECTIVE

L-carnitine (LC), a vital nutritional supplement, plays a crucial role in myocardial health and exhibits significant cardioprotective effects. LC, being the principal constituent of clinical-grade supplements, finds extensive application in the recovery and treatment of diverse cardiovascular and cerebrovascular disorders. However, controversies persist regarding the utilization of LC in nervous system diseases, with varying effects observed across numerous mental and neurological disorders. This article primarily aims to gather and analyze database information to comprehensively summarize the therapeutic potential of LC in patients suffering from nervous system diseases while providing valuable references for further research.

METHODS

A comprehensive search was conducted in PubMed, Web Of Science, Embase, Ovid Medline, Cochrane Library and Clinicaltrials.gov databases. The literature pertaining to the impact of LC supplementation on neurological or psychiatric disorders in patients was reviewed up until November 2023. No language or temporal restrictions were imposed on the search.

RESULTS

A total of 1479 articles were retrieved, and after the removal of duplicates through both automated and manual exclusion processes, 962 articles remained. Subsequently, a meticulous re-screening led to the identification of 60 relevant articles. Among these, there were 12 publications focusing on hepatic encephalopathy (HE), while neurodegenerative diseases (NDs) and peripheral nervous system diseases (PNSDs) were represented by 9 and 6 articles, respectively. Additionally, stroke was addressed in five publications, whereas Raynaud's syndrome (RS) and cognitive disorder (CD) each had three dedicated studies. Furthermore, migraine, depression, and amyotrophic lateral sclerosis (ALS) each accounted for two publications. Lastly, one article was found for other symptoms under investigation.

CONCLUSION

In summary, LC has demonstrated favorable therapeutic effects in the management of HE, Alzheimer's disease (AD), carpal tunnel syndrome (CTS), CD, migraine, neurofibromatosis (NF), PNSDs, RS, and stroke. However, its efficacy appears to be relatively limited in conditions such as ALS, ataxia, attention deficit hyperactivity disorder (ADHD), depression, chronic fatigue syndrome (CFS), Down syndrome (DS), and sciatica.

Effect of parenteral L-carnitine in hospitalized patients with moderate to severe COVID-19: A randomized double-blind clinical trial

Introduction

Pro-inflammatory responses have an important role in developing coronavirus disease 2019 (COVID-19). L-carnitine (LC) has been known to possess anti-inflammatory, anticoagulant, and antiviral effects. So, we aimed to evaluate the efficacy of LC in hospitalized patients with moderate-to-severe COVID-19.

Methods

This double-blind, placebo-controlled, randomized clinical trial was conducted on hospitalized patients with moderate to severe COVID-19. The patients were randomized (1:1) to receive LC (n = 50) at a dose of 20 mg/kg or matching placebo (n = 51) from normal saline once daily for 14 days or until hospitalization and standard care. The primary outcome was hospital mortality and disease severity according to the World Health Organization's clinical progression scale. We also assessed the free carnitine level at baseline and the end of the study. C-reactive protein (CRP), ferritin, D-dimer, lactate dehydrogenase (LDH), and improvement of respiratory conditions were chosen as secondary outcomes.

Results

From 104 patients who met the inclusion criteria, 101 individuals' data were analyzed. The LC group showed a significant reduction in LDH levels (P = 0.003), although CRP, ferritin, and D-dimer levels did not significantly differ from the placebo group. Also, no significant difference was observed in disease severity, oxygenation status, hospital mortality, or hospital stay between the two groups. Additionally, there was no increase in serum-free carnitine levels in the LC group (P > 0.05 for all).

Conclusion

The results of the current study did not support the superiority of LC over placebo in improving oxygenation, decreasing mortality, and hospital stay, as well as CRP, ferritin, and D-dimer in moderate to severe COVID-19 patients.

Trial Registration

IRCT20170609034406N10; https://en.irct.ir/trial/60306.

The effects of L-carnitine supplementation on inflammation, oxidative stress, and clinical outcomes in critically Ill patients with sepsis: a randomized, double-blind, controlled trial

BACKGROUND

Sepsis, a life-threatening organ dysfunction caused by a host's dysregulated response to infection with an inflammatory process, becomes a real challenge for the healthcare systems. L-carnitine (LC) has antioxidant and anti-inflammatory properties as in previous studies. Thus, we aimed to determine the effects of LC on inflammation, oxidative stress, and clinical parameters in critically ill septic patients.

METHODS

A randomized double-blinded controlled trial was conducted. A total of 60 patients were randomized to receive LC (3 g/day, n = 30) or placebo (n = 30) for 7 days. Inflammatory and oxidative stress parameters (C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), superoxide dismutase (SOD), malondialdehyde (MDA), total antioxidant capacity (TAC), 28-day mortality rate, and some monitoring variables were evaluated.

RESULTS

There was no statistically significant difference between study arms in baseline characteristics and disease severity scores. CRP (p < 0.001) and ESR (p: 0.004) significantly reduced, and SOD (p < 0.001) and TAC (p < 0.001) significantly improved in the LC group after 7 days. Between-group analysis revealed a significant reduction in CRP (p: 0.001) and serum chloride (p: 0.032), an increase in serum albumin (p: 0.036) and platelet (p: 0.004) significantly, and an increase in SOD marginally (p: 0.073). The 28-day mortality rate was also lower in the LC group compared with placebo (7 persons vs. 15 persons) significantly (odds ratio: 0.233, p: 0.010).

CONCLUSIONS

L-carnitine ameliorated inflammation, enhanced antioxidant defense, reduced mortality, and improved some clinical outcomes in critically ill patients with sepsis.

TRIAL REGISTRATION

IRCT20201129049534N1; May 2021.

Effects of L-Carnitine and Coenzyme Q10 Supplementation on Lower Urinary Tract Symptoms in Men with Benign Prostatic Hyperplasia: A Randomized, Controlled, Clinical Trial

The prevalence of benign prostatic hyperplasia (BPH) and its associated lower urinary tract symptoms (LUTS) increases with age. Considering that BPH drug treatment is associated with complications, this study aimed to investigate the effects of L-carnitine (LC) and Coenzyme Q10 (CoQ10) supplementation as an adjunct therapy to finasteride in the management of LUTS in older men affected with BPH. Fifty eligible volunteers (25 per group) were randomly assigned to either intervention (finasteride + LC and CoQ10 supplements) or control (finasteride + placebo) groups. International prostate symptom score (IPSS), international index of erectile function (IIEF), quality of life index (QoL), as well as serum levels of Prostate-specific antigen (PSA), were assessed. Prostate ultrasound evaluation was also performed, before and after 8 wk of intervention. Supplementation with LC and CoQ10 led to a significant decrease in prostate volume (p < 0.001) as well as a significant increase in IIEF (p < 0.001), compared to the control group. However, there were no significant between-group differences in IPSS (p = 0.503), QoL scores (p = 0.339), and PSA levels (p = 0.482). CoQ10 and LC supplements might be beneficial in combination with standard therapies in the management of BPH and its related complications.

Effect of L-carnitine in Ameliorating Lipopolysaccharide-Induced Cardiomyocyte Injury via MAPK Signaling

The present study aimed to elucidate whether L-carnitine (LC) protected H9c2 cells and its underlying mechanisms. Cell counting kit-8 (CCK-8) assay was used to evaluate cell viability. Apoptosis, cell morphology, and lactate dehydrogenase (LDH) assessment were used to prove effects of lipopolysaccharide (LPS) and LC on H9c2 cells. RT-qPCR and western blot assays were hired to evaluate the mRNA and protein expression levels, respectively. ELISA assay was performed to determine the released protein levels. Reactive oxygen species (ROS) level was evaluated by immunofluorescence and flow cytometry. LC was revealed to protect H9c2 cells against LPS-induced injury as indicated by increased cell viability, reduced apoptosis ratio and LDH level. LC treatment also reduced BAX expression as well as up-regulated Bcl-2 expression under LPS treatment. Mechanically, LC reduced oxidative stress and ameliorated the mitochondrial injury through modulating extracellular signal-regulated kinase 1/2 and c-Jun N-terminal protein kinase c-Jun N-terminal protein kinase phosphorylation levels as indicated by decreased membrane potential, increased ATP production and mtDNA expression. We found that LC ameliorates LPS-induced cardiomyocyte injury by abrogating cell apoptosis ratio, ROS levels, as well as mitochondrial dysfunction via mitogen-activated protein kinase signaling. Our findings revealed a potential drug for sepsis or LPS-induced cardiomyocyte injury.

Blood and liver telomere length, mitochondrial DNA copy number, and hepatic gene expression of mitochondrial dynamics in mid-lactation cows supplemented with l-carnitine under systemic inflammation

The current study was conducted to examine the effect of l-carnitine (LC) supplementation on telomere length and mitochondrial DNA copy number (mtDNAcn) per cell in mid-lactation cows challenged by lipopolysaccharide (LPS) in blood and liver. The mRNA abundance of 31 genes related to inflammation, oxidative stress, and the corresponding stress response mechanisms, the mitochondrial quality control and the protein import system, as well as the phosphatidylinositol 3-kinase/protein kinase B pathway, were assessed using microfluidics integrated fluidic circuit chips (96.96 dynamic arrays). In addition to comparing the responses in cows with or without LC, our objectives were to characterize the oxidative and inflammatory status by assessing the circulating concentration of lactoferrin (Lf), haptoglobin (Hp), fibrinogen, derivates of reactive oxygen metabolites (dROM), and arylesterase activity (AEA), and to extend the measurement of Lf and Hp to milk. Pluriparous Holstein cows were assigned to either a control group (CON, n = 26) or an LC-supplemented group (CAR; 25 g LC/cow per day; d 42 ante partum to d 126 postpartum (PP), n = 27). On d 111 PP, each cow was injected intravenously with LPS (Escherichia coli O111:B4, 0.5 µg/kg). The mRNA abundance was examined in liver biopsies of d -11 and +1 relative to LPS administration. Plasma and milk samples were frequently collected before and after the challenge. After LPS administration, circulating plasma fibrinogen and serum dROM concentrations increased, whereas AEA decreased. Moreover, serum P4 initially increased by 3 h after LPS administration and declined thereafter irrespective of grouping. The Lf concentrations increased in both groups after LPS administration, with the CAR group showing greater concentrations in serum and milk than the CON group. After LPS administration, telomere length in blood increased, whereas mtDNAcn per cell decreased; however, both remained unaffected in liver. For mitochondrial protein import genes, the hepatic mRNA abundance of the translocase of the mitochondrial inner membrane (TIM)-17B was increased in CAR cows. Moreover, TIM23 increased in both groups after LPS administration. Regarding the mRNA abundance of genes related to stress response mechanisms, 7 out of 14 genes showed group × time interactions, indicating a (local) protective effect due to the dietary LC supplementation against oxidative stress in mid-lactating dairy cows. For mtDNAcn and telomere length, the effects of the LPS-induced inflammation were more pronounced than the dietary supplementation of LC. Dietary LC supplementation affected the response to LPS primarily by altering mitochondrial dynamics. Regarding mRNA abundance of genes related to the mitochondrial protein import system, the inner mitochondrial membrane translocase (TIM complex) seemed to be more sensitive to dietary LC than the outer mitochondrial membrane translocase (TOM complex).

Prevention of Re-attempt Suicide Through Brief Contact Interventions: A Systematic Review, Meta-analysis, and Meta-regression of Randomized Controlled Trials

Brief contact intervention (BCI) is a low-cost intervention to prevent re-attempt suicide. This meta-analysis and meta-regression study aimed to evaluate the effect of BCI on re-attempt prevention following suicide attempts (SAs). We systematically searched using defined keywords in MEDLINE, Embase, and Scopus up to April, 2023. All randomized controlled trials (RCTs) were eligible for inclusion after quality assessment. Random-effects model and subgroup analysis were used to estimate pooled risk difference (RD) and risk ratio (RR) between BCI and re-attempt prevention with 95% confidence intervals (CIs). Meta-regression analysis was carried out to explore the potential sources of heterogeneity. The pooled estimates were (RD = 4%; 95% CI 2-6%); and (RR = 0.62; 95% CI 0.48-0.77). Subgroup analysis demonstrated that more than 12 months intervention (RR = 0.46; 95% CI 0.10-0.82) versus 12 months or less (RR = 0.67; 95% CI 0.54-0.80) increased the effectiveness of BCI on re-attempt suicide reduction. Meta-regression analysis explored that BCI time (more than 12 months), BCI type, age, and female sex were the potential sources of the heterogeneity. The meta-analysis indicated that BCI could be a valuable strategy to prevent suicide re-attempts. BCI could be utilized within suicide prevention strategies as a surveillance component of mental health since BCI requires low-cost and low-educated healthcare providers.

The effects of L-carnitine supplementation on inflammatory and anti-inflammatory markers in adults: a systematic review and dose-response meta-analysis

L-carnitine supplementation may be beneficial in improving inflammatory conditions and reducing the level of inflammatory cytokines. Therefore, according to the finding of randomized controlled trials (RCTs), the systematic review and meta-analysis aimed to investigate the effect of L-carnitine supplementation on inflammation in adults. To obtain acceptable articles up to October 2022, a thorough search was conducted in databases including PubMed, ISI Web of Science, the Cochrane Library, and Scopus. A random-effects model was used to estimate the weighted mean difference (WMD). We included the 48 RCTs (n = 3255) with 51 effect sizes in this study. L-carnitine supplementation had a significant effect on C-reactive protein (CRP) (p < 0.001), interleukin-6 (IL-6) (p = 0.001), tumor necrosis factor-α (TNF-α) (p = 0.002), malondialdehyde (MDA) (p = 0.001), total antioxidant capacity (TAC) (p = 0.029), alanine transaminase (ALT) (p < 0.001), and aspartate transaminase (AST) (p < 0.001) in intervention, compared to the placebo group. Subgroup analyses showed that L-carnitine supplementation had a lowering effect on CRP and TNF-α in trial duration ≥ 12 weeks in type 2 diabetes and BMI ≥ 25 kg/m2. L-carnitine supplementation reduced ALT levels in overweight and normal BMI subjects at any trial dose and trial duration ≥ 12 weeks and reduced AST levels in overweight subjects and trial dose ≥ 2 g/day. This meta-analysis revealed that L-carnitine supplementation effectively reduces the inflammatory state by increasing the level of TAC and decreasing the levels of CRP, IL-6, TNF-α and MDA in the serum.

Clinical Significance of Carnitine in the Treatment of Cancer: From Traffic to the Regulation

Metabolic reprogramming is a common hallmark of cancer cells. Cancer cells exhibit metabolic flexibility to maintain high proliferation and survival rates. In other words, adaptation of cellular demand is essential for tumorigenesis, since a diverse supply of nutrients is required to accommodate tumor growth and progression. Diversity of carbon substrates fueling cancer cells indicate metabolic heterogeneity, even in tumors sharing the same clinical diagnosis. In addition to the alteration of glucose and amino acid metabolism in cancer cells, there is evidence that cancer cells can alter lipid metabolism. Some tumors rely on fatty acid oxidation (FAO) as the primary energy source; hence, cancer cells overexpress the enzymes involved in FAO. Carnitine is an essential cofactor in the lipid metabolic pathways. It is crucial in facilitating the transport of long-chain fatty acids into the mitochondria for β-oxidation. This role and others played by carnitine, especially its antioxidant function in cellular processes, emphasize the fine regulation of carnitine traffic within tissues and subcellular compartments. The biological activity of carnitine is orchestrated by specific membrane transporters that mediate the transfer of carnitine and its derivatives across the cell membrane. The concerted function of carnitine transporters creates a collaborative network that is relevant to metabolic reprogramming in cancer cells. Here, the molecular mechanisms relevant to the role and expression of carnitine transporters are discussed, providing insights into cancer treatment.

The effects of N-acetylcysteine on ovulation and sex hormones profile in women with polycystic ovary syndrome: a systematic review and meta-analysis

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases characterised by unusual levels of sex hormones and dysfunction of the ovaries. The infertility rate is high among patients with PCOS. Unusual hormonal status can lead to the inability of ovaries to release functional and mature follicles. Clinical trials on the effects of N-acetylcysteine (NAC) supplementation on ovulation and sex hormones profile in women with PCOS have been controversial. We performed a systematic review and meta-analysis to evaluate the potential effects of NAC supplementation on ovulation and sex hormones profile. PubMed, Scopus, Embase, Web of Science and Cochrane Central library international databases were searched till September 2021. Meta-analysis was performed using a random-effects approach in case of significant between-study heterogeneity. Eighteen studies, including 2185 participants, were included in the present meta-analysis. NAC significantly reduced total testosterone (TT) levels (standardised mean difference (SMD): −0·25 ng/ml; 95 % CI (−0·39, −0·10); ‘P < 0·001’, I2 = 53·9 %, P = 0·034) and increased follicle-stimulating hormone (FSH) levels (SMD: 0·39 mg/ml; 95 % CI (0·07, 0·71); P = 0·01, I2 = 70·9 %, P = 0·002). Oestrogen levels also increased after correcting publication bias. However, no significant effect was observed on the number of follicles, endometrial thickness, progesterone, serum luteinising hormone levels and sex hormone-binding globulin. The results indicated that NAC supplementation decreased TT levels and increased FSH levels. Overall, NAC supplementation might be effective in the improvement of reproductive system function in patients with PCOS.

Plasma metabolomic characterization of SARS-CoV-2 Omicron infection

Omicron variants of SARS-CoV-2 have spread rapidly worldwide; however, most infected patients have mild or no symptoms. This study aimed to understand the host response to Omicron infections by performing metabolomic profiling of plasma. We observed that Omicron infections triggered an inflammatory response and innate immune, and adaptive immunity was suppressed, including reduced T-cell response and immunoglobulin antibody production. Similar to the original SARS-CoV-2 strain circulating in 2019, the host developed an anti-inflammatory response and accelerated energy metabolism in response to Omicron infection. However, differential regulation of macrophage polarization and reduced neutrophil function has been observed in Omicron infections. Interferon-induced antiviral immunity was not as strong in Omicron infections as in the original SARS-CoV-2 infections. The host response to Omicron infections increased antioxidant capacity and liver detoxification more than in the original strain. Hence, these findings suggest that Omicron infections cause weaker inflammatory alterations and immune responses than the original SARS-CoV-2 strain.

Evaluation of L-Carnitine Potential in Improvement of Male Fertility

L-carnitine, through its antioxidant potential, plays a significant role in reducing ROS production in male genital tract; therefore, fundamental improvements in spermatogenesis process and sperm structural and functional parameters in seminal plasma can be observed by treatment with L-carnitine. A literature search was performed using PubMed (including Medline) from the database earliest inception to 2021. Eligibility criteria included studies on protective effects of L-carnitine against damages to the male reproductive system. Based on the findings of the current study, L-carnitine has an effective potential to protect testis and improve conventional and functional sperm parameters against ROS-induced damages by sperm cryopreservation, busulfan treatment, and radiation.

L-Carnitine and synbiotic co-supplementation: beneficial effects on metabolic-endotoxemia, meta-inflammation, and oxidative-stress biomarkers in obese patients: a double blind, randomized, controlled clinical trial

Obesity, a chronic pandemic disease, is characterized by low-grade chronic inflammation, accompanied by over-expression of pro-inflammatory cytokines, thereby contributing to metabolic disorders pathogenesis. Oxidative-stress, an adverse cellular response to adipocyte hypertrophy, promotes inflammation. Furthermore, gut-microbiota dysbiosis may induce oxidative-stress, low-grade inflammation, and metabolic-endotoxemia as major drivers of obesity. Functional-foods/nutraceuticals have attracted extensive attention due to their plausible anti-inflammatory/anti-oxidative properties; evidence supports the superiority of the nutraceutical combined-supplementation approach versus conventional mono-therapies. Current data suggest the anti-oxidative/anti-inflammatory properties of either L-carnitine or pre/pro/synbiotics. This trial compared the effects of co-supplementing L-carnitine and multi-species/multi-strain synbiotic versusL-carnitine mono-therapy on inflammatory/anti-inflammatory, oxidative-stress, and metabolic-endotoxemia biomarkers in 46 female obese patients, receiving either co-supplementation (L-carnitine-tartrate (2 × 500 mg d^-1) + multi-species/multi-strain synbiotic (1 capsule per day)) or mono-therapy (L-carnitine-tartrate (2 × 500 mg d^-1) + maltodextrin (1 capsule per day)) for eight weeks. L-Carnitine + synbiotic co-supplementation significantly decreased interleukin-6 (IL-6, -33.98%), high-sensitivity-C-reactive-protein (hs-CRP, -10%), tumor-necrosis-factor-alpha (TNF-α, -18.73%), malondialdehyde (MDA, -21.73%), and lipopolysaccharide (LPS, -10.14%), whereas the increase in interleukin-10 (IL-10, 7.69%) and total-antioxidant-capacity (TAC, 4.13%) levels was not significant. No significant changes were observed for the above-mentioned parameters in the L-carnitine + placebo group, except for a significant reduction in IL-10 (-17.59%) and TNF-α (-14.78%); however, between-group differences did not reach the significant threshold. Co-supplementing L-carnitine + multi-strain synbiotic led to significant amelioration of inflammatory, oxidative, and metabolic-endotoxemia responses in female obese patients; nevertheless, no improving effects were observed in patients receiving single-supplementation, suggesting that L-carnitine + synbiotic co-supplementation might represent an adjuvant approach to improve oxidative-stress/pro-inflammatory indicators in women with obesity, possibly through beneficial effects of the synbiotic alone. Further longer duration studies with higher doses of L-carnitine in a three-group setting are warranted to elucidate the possibility of synergistic or complementary mechanisms.

Normalization of lipid oxidation defects arising from hypoxia early posthepatectomy prevents liver failure in mouse

Surgical liver failure (SLF) develops when a marginal amount of hepatic mass is left after surgery, such as following excessive resection. SLF is the commonest cause of death due to liver surgery; however, its etiology remains obscure. Using mouse models of standard hepatectomy (sHx) (68%, resulting in full regeneration) or extended hepatectomy (eHx) (86%/91%, causing SLF), we explored the causes of early SLF related to portal hyperafflux. Assessing the levels of HIF2A with or without oxygenating agent inositol trispyrophosphate (ITPP) indicated hypoxia early after eHx. Subsequently, lipid oxidation (PPARA/PGC1α) was downregulated and associated with persisting steatosis. Mild oxidation with low-dose ITPP reduced the levels of HIF2A, restored downstream PPARA/PGC1α expression along with lipid oxidation activities (LOAs), and normalized steatosis and other metabolic or regenerative SLF deficiencies. Promotion of LOA with L-carnitine likewise normalized the SLF phenotype, and both ITPP and L-carnitine markedly raised survival in lethal SLF. In patients who underwent hepatectomy, pronounced increases in serum carnitine levels (reflecting LOA) were associated with better recovery. Lipid oxidation thus provides a link between the hyperafflux of O₂-poor portal blood, the metabolic/regenerative deficits, and the increased mortality typifying SLF. Stimulation of lipid oxidation-the prime regenerative energy source-particularly through L-carnitine may offer a safe and feasible way to reduce SLF risks in the clinic.

Biomedical role of L-carnitine in several organ systems, cellular tissues, and COVID-19

Carnitine is a conditionally necessary vitamin that aids in energy creation and fatty acid metabolism. Its bioavailability is higher in vegetarians than in meat-eaters. Deficits in carnitine transporters occur because of genetic mutations or in conjunction with other illnesses. Carnitine shortage can arise in health issues and diseases-including hypoglycaemia, heart disease, starvation, cirrhosis, and ageing-because of abnormalities in carnitine control. The physiologically active form of L-carnitine supports immunological function in diabetic patients. Carnitine has been demonstrated to be effective in the treatment of Alzheimer's disease, several painful neuropathies, and other conditions. It has been used as a dietary supplement for the treatment of heart disease, and it also aids in the treatment of obesity and reduces blood glucose levels. Therefore, L-carnitine shows the potential to eliminate the influences of fatigue in COVID-19, and its consumption is recommended in future clinical trials to estimate its efficacy and safety. This review focused on carnitine and its effect on tissues, covering the biosynthesis, metabolism, bioavailability, biological actions, and its effects on various body systems and COVID-19.

Large-scale genetic correlation scanning and causal association between deep vein thrombosis and human blood metabolites

Deep vein thrombosis (DVT) refers to the abnormal coagulation of blood in a deep vein. Recently, some studies have found that metabolites are related to the occurrence of DVT and may serve as new markers for the diagnosis of DVT. In this study, we used the GWAS summary dataset of blood metabolites and DVT to perform a large-scale genetic correlation scan of DVT and blood metabolites to explore the correlation between blood metabolites and DVT. We used GWAS summary data of DVT from the UK Biobank (UK Biobank fields: 20002) and GWAS summary data of blood metabolites from a previously published study (including 529 metabolites in plasma or serum from 7824 adults from two European population studies) for genetic correlation analysis. Then, we conducted a causal study between the screened blood metabolites and DVT by Mendelian randomization (MR) analysis. In the first stage, genetic correlation analysis identified 9 blood metabolites that demonstrated a suggestive association with DVT. These metabolites included Valine (correlation coefficient = 0.2440, P value = 0.0430), Carnitine (correlation coefficient = 0.1574, P value = 0.0146), Hydroxytryptophan (correlation coefficient = 0.2376, P value = 0.0360), and 1-stearoylglycerophosphoethanolamine (correlation coefficient = - 0.3850, P value = 0.0258). Then, based on the IVW MR model, we analysed the causal relationship between the screened blood metabolites and DVT and found that there was a suggestive causal relationship between Hydroxytryptophan (exposure) and DVT (outcome) (β = - 0.0378, se = 0.0163, P = 0.0204). Our study identified a set of candidate blood metabolites that showed a suggestive association with DVT. We hope that our findings will provide new insights into the pathogenesis and diagnosis of DVT in the future.

The effects of L-carnitine supplementation on inflammatory factors, oxidative stress, and clinical outcomes in patients with sepsis admitted to the intensive care unit (ICU): study protocol for a double blind, randomized, placebo-controlled clinical trial

BACKGROUND

Sepsis is a common cause for admission to the intensive care unit (ICU), and its incidence has been increasing. It is associated with a significant increase in serum inflammatory biomarkers such as C-reactive protein (CRP) and cytokines such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor (TNF). Sepsis is also associated with pathophysiological changes that include fluid accumulation in the lungs, eventually leading to acute respiratory distress syndrome (ARDS), tissue edema, hypotension, and acute kidney injury (AKI). Conventional therapies include antibiotics, but these may have important adverse effects, so novel therapeutic approaches are required. In animal studies, L-carnitine improves antioxidant status, and in some clinical trials, it has been shown to reduce inflammation. It has also been shown to improve respiratory distress and help maintain coenzyme A homeostasis, metabolic flexibility, promoting the normal function of the tricarboxylic acid (TCA) cycle, and oxidation of fatty acids by peroxisomes. We aim to determine the effects of very high doses of L-carnitine on inflammatory factors, oxidative stress, and clinical outcomes of patients with sepsis in ICU.

METHOD AND DESIGN

In this double-blind, randomized controlled clinical trial, we will use block randomization of 60 patients with sepsis, aged between 20 and 65 years from Al-Zahra Hospital, Isfahan, Iran. The intervention group (n = 30) will receive three capsules of L-carnitine (each capsule contains 1000 mg L-carnitine; totally 3000 mg/day) for 7 days, and a control group (n = 30) will receive a placebo with the same dose and for the same duration in addition to usual care. At baseline, scores for clinical and nutritional status (Acute Physiology and Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA), Quick SOFA (qSOFA), and NUTRIC Score) will be assessed. At beginning and end point of the study, inflammatory markers (CRP, erythrocyte sedimentation rate (ESR)), oxidative stress status (total oxidative stress (TOS), total antioxidant capacity (TAC)), and clinical variables will be evaluated also. The mortality rate will be assessed within 28 days of the beginning of the intervention.

DISCUSSION

Because of the anti-inflammatory and antioxidant properties of L-carnitine, it is possible that using a high dose of 3000 mg daily of this nutritional supplement may reduce inflammation and oxidative stress and improve subsequent mortality of critically ill patients with sepsis.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials IRCT20201129049534N1 . Registered on 2 May 2021.

Effects of L-carnitine supplementation in patients with mild-to-moderate COVID-19 disease: a pilot study

BACKGROUND

The present single-center clinical trial was designed to evaluate the potential benefits of L-carnitine supplementation in patients with COVID-19 disease.

METHODS AND PATIENTS

The study was conducted on 75 patients with mild-to-moderate COVID-19 hospitalized in Shahid Beheshti Hospital-Hamadan, IRAN. The participants were randomly divided into intervention (n = 32) and control groups (n = 43). The control group received their standard hospital treatment only. In addition to standard medications, the intervention group received 3000 mg oral L-carnitine daily in three divided doses for five days. The blood samples were collected and para-clinical parameters were measured at the beginning and end of the treatment. Clinical outcomes were also recorded, and data were analyzed using χ² and t-tests.

RESULTS

Higher means of O2 saturation were observed in the intervention rather than in the control group. Mean erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were significantly lower in the intervention group. Furthermore, mean alkaline phosphatase (ALP) activity and lactate dehydrogenase (LDH) were lower in the intervention group. Also, lower mean serum creatine phosphokinase (CPK) was observed in the intervention group. No significant differences were observed in terms of clinical symptoms; however, six patients (14%) in the control group died due to the complications of COVID-19, while all patients in the intervention group survived.

CONCLUSION

Taken together, L-carnitine can be considered as a drug supplement in patients with COVID-19.

Urinary metabotype of severe asthma evidences decreased carnitine metabolism independent of oral corticosteroid treatment in the U-BIOPRED study

INTRODUCTION

Asthma is a heterogeneous disease with poorly defined phenotypes. Severe asthmatics often receive multiple treatments including oral corticosteroids (OCS). Treatment may modify the observed metabotype, rendering it challenging to investigate underlying disease mechanisms. Here, we aimed to identify dysregulated metabolic processes in relation to asthma severity and medication.

METHODS

Baseline urine was collected prospectively from healthy participants (n=100), mild-to-moderate asthmatics (n=87) and severe asthmatics (n=418) in the cross-sectional U-BIOPRED cohort; 12-18-month longitudinal samples were collected from severe asthmatics (n=305). Metabolomics data were acquired using high-resolution mass spectrometry and analysed using univariate and multivariate methods.

RESULTS

Ninety metabolites were identified, with 40 significantly altered (p<0.05, FDR<0.05) in severe asthma and 23 by OCS use. Multivariate modelling showed that observed metabotypes in healthy participants and mild-to-moderate asthmatics differed significantly from severe asthmatics (p=2.6×10^-20), OCS-treated asthmatics differed significantly from non-treated (p=9.5×10^-4), and longitudinal metabotypes demonstrated temporal stability. Carnitine levels evidenced the strongest OCS-independent decrease in severe asthma. Reduced carnitine levels were associated with mitochondrial dysfunction via decreases in pathway enrichment scores of fatty acid metabolism and reduced expression of the carnitine transporter SLC22A5 in sputum and bronchial brushings.

CONCLUSIONS

This is the first large-scale study to delineate disease- and OCS-associated metabolic differences in asthma. The widespread associations with different therapies upon the observed metabotypes demonstrate the necessity to evaluate potential modulating effects on a treatment- and metabolite-specific basis. Altered carnitine metabolism is a potentially actionable therapeutic target that is independent of OCS treatment, highlighting the role of mitochondrial dysfunction in severe asthma.

L-carnitine: Searching for New Therapeutic Strategy for Sepsis Management

In this review, we discussed the biological targets of carnitine, its effects on immune function, and how L-carnitine supplementation may help critically ill patients. L-carnitine is a potent antioxidant. L-carnitine depletion has been observed in prolonged intensive care unit (ICU) stays, while L-carnitine supplementation has beneficial effects in health promotion and regulation of immunity. It is essential for the uptake of fatty acids into mitochondria. By inhibiting the ubiquitin-proteasome system, down-regulation of apelin receptor in cardiac tissue, and reducing β-oxidation of fatty acid, carnitine may decrease vasopressor requirement in septic shock and improve clinical outcomes of this group of patients. We also have an overview of animal and clinical studies that have been recruited for evaluating the beneficial effects of L-carnitine in the management of sepsis/ septic shock. Additional clinical data are required to evaluate the optimal daily dose and duration of L-carnitine supplementation.

Diabetes Mellitus and Cardiovascular Diseases: Nutraceutical Interventions Related to Caloric Restriction

Type 2 diabetes (T2DM) and cardiovascular disease (CVD) are closely associated and represent a key public health problem worldwide. An excess of adipose tissue, NAFLD, and gut dysbiosis establish a vicious circle that leads to chronic inflammation and oxidative stress. Caloric restriction (CR) is the most promising nutritional approach capable of improving cardiometabolic health. However, adherence to CR represents a barrier to patients and is the primary cause of therapeutic failure. To overcome this problem, many different nutraceutical strategies have been designed. Based on several data that have shown that CR action is mediated by AMPK/SIRT1 activation, several nutraceutical compounds capable of activating AMPK/SIRT1 signaling have been identified. In this review, we summarize recent data on the possible role of berberine, resveratrol, quercetin, and L-carnitine as CR-related nutrients. Additionally, we discuss the limitations related to the use of these nutrients in the management of T2DM and CVD.

Noopept Attenuates Diabetes-Mediated Neuropathic Pain and Oxidative Hippocampal Neurotoxicity via Inhibition of TRPV1 Channel in Rats

Neuropathic pain and oxidative neurotoxicity are two adverse main actions of diabetes mellitus (DM). The expression levels of calcium ion (Ca²⁺) permeable TRPV1 channels are high in the dorsal root ganglion (DRGs) and hippocampus (HIPPO). TRPV1 is activated by capsaicin and reactive free oxygen radicals (fROS) to mediate peripheral neuropathy and neurotoxicity. Noopept (NP) acted several protective antioxidant actions against oxidative neurotoxicity. As DM is known to increase the levels of fROS, the protective roles of antioxidant NP were evaluated on the DM-mediated neurotoxicity and neuropathic pain via the modulation of TRPV1 in rats. Thirty-six rats were equally divided into control, NP, DM (streptozotocin, STZ), and STZ + NP groups. A decrease on the STZ-mediated increase of neuropathic pain (via the analyses of Von Frey and hot plate) and blood glucose level was observed by the treatment of NP. A protective role of NP via downregulation of TRPV1 activity on the STZ-induced increase of apoptosis, mitochondrial fROS, lipid peroxidation, caspase -3 (CASP-3), caspase -9 (CASP-9), TRPV1 current density, glutathione (GSH), cytosolic free Zn²⁺, and Ca²⁺ concentrations in the DRGs and HIPPO was also observed. The STZ-mediated decrease of glutathione peroxidase, GSH, vitamin E, and β-carotene concentrations in the brain cortex, erythrocyte, liver, kidney, and plasma was also attenuated by the treatment of NP. The STZ-mediated increase of TRPV1, CASP-3, and CASP-9 expressions was decreased in the DRGs and HIPPO by the treatment of NP. In conclusion, the treatment of NP induced protective effects against STZ-induced adverse peripheral pain and HIPPO oxidative neurotoxicity. These effects might attribute to the potent antioxidant property of NP.

The effects of L-carnitine on renal function and gene expression of caspase-9 and Bcl-2 in monosodium glutamate-induced rats

BACKGROUND

Monosodium glutamate (MSG) is frequently consumed as a flavor enhancer or food additive. Possible damages induced by MSG effects on some organs have been stated in experimental animal models. The aim of the present study was to evaluate the protective effects of L-carnitine (L-ca) on the renal tissue in MSG-Induced Rats.

METHODS

In this regard, 60 male rats were randomly divided into six groups (n = 10/each): 1 (Control); 2 (sham); 3 (L-carnitine 200 mg/kg b.w); 4 (MSG 3 g/kg b.w); 5 (MSG + L-carnitine 100 mg/kg); and 6 (MSG + L-carnitine 200 mg/kg). After 6 months, the rats were sacrificed, the blood sample collected and the kidneys harvested for evaluation of biochemical analytes, genes expression, and histopathological changes.

RESULTS

MSG significantly increased the serum level of MDA, BUN, creatinine, uric acid and renal Caspase-9, NGAL and KIM-1 expression, but it decreased the serum activity also renal expression of SOD, catalase, GPX, and Bcl-2 expression compared to the control group. Treatment with L-ca significantly reduced the serum BUN, creatinine, uric acid and MDA level and increased catalase, GPX and SOD compared to the MSG group. However, only administration of L-ca 200 significantly decreased the caspase-9, NGAL and KIM-1; also, it increased the Bcl-2 expression in the kidney compared to the MSG group.

CONCLUSIONS

Our findings indicated that L-carnitine had a major impact on the cell protection and might be an effective therapy in ameliorating the complications of the kidney induced by MSG via its antioxidant and anti-apoptotic properties.

L-Carnitine Tartrate Downregulates the ACE2 Receptor and Limits SARS-CoV-2 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for one of the worst pandemics in modern history. Several prevention and treatment strategies have been designed and evaluated in recent months either through the repurposing of existing treatments or the development of new drugs and vaccines. In this study, we show that L-carnitine tartrate supplementation in humans and rodents led to significant decreases of key host dependency factors, notably angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), and Furin, which are responsible for viral attachment, viral spike S-protein cleavage, and priming for viral fusion and entry. Interestingly, pre-treatment of Calu-3, human lung epithelial cells, with L-carnitine tartrate led to a significant and dose-dependent inhibition of the infection by SARS-CoV-2. Infection inhibition coincided with a significant decrease in ACE2 mRNA expression levels. These data suggest that L-carnitine tartrate should be tested with appropriate trials in humans for the possibility to limit SARS-CoV-2 infection.