L-carnitine ameliorated fasting-induced fatigue, hunger, and metabolic abnormalities in patients with metabolic syndrome: a randomized controlled study

Estimation of L-carnitine levels in diabetic completely edentulous patients for implant diagnosis: A cross-sectional study

Background

Carnitine is effective in preventing the accumulation of end products related to lipid peroxidation due to its anti-inflammatory and antioxidant effects. Carnitine also exerts a significant anti-inflammatory role through the downregulation of the nuclear factor kappa beta pathway, which leads to a decrease in the expression of pro-inflammatory cytokines.The aim of the study was to estimate the L-carnitine (L-C) levels in diabetic completely edentulous patients.

Materials and Methods

A cross-sectional study was conducted after the selection of 60 samples based on the inclusion and exclusion criteria. The collected saliva samples were utilized to measure the levels of L-C using the sandwich enzyme-linked immunosorbent assay (ELISA) method. One hundred microliters of sample was applied to a particular row of wells and incubated for an hour as part of the sandwich ELISA procedure. After the wells had been cleaned, a second batch of monoclonal L-C was added, and they were once more incubated for an hour. The horseradish peroxidase substrate was then applied after washing the second batch as well. To allow the blue-to-yellow color transition, the wells were kept steady. Following the observation of the color shift, the OD was measured, and the concentration was determined using the sandwich ELISA kit's standard curve as an intercept. The data were statistically analyzed using the independent t-test (significant level P < 0.05) and were tabulated.

Results

The L-C levels have higher levels in nondiabetic patients than in diabetic patients. The difference in the baseline mean value between the groups was statistically significant (P = 0.00). Although it is statistically significant (P = 0.00), the mean value for diabetic individuals is 0.19 as opposed to 0.29 for nondiabetic patients.

Conclusion

Based on the findings, it can be concluded that L-C improves insulin sensitivity and glucose disposal in diabetic completely edentulous patients.

Nutrient Therapy for the Improvement of Fatigue Symptoms

Fatigue, characterised by lack of energy, mental exhaustion and poor muscle endurance which do not recover following a period of rest, is a common characteristic symptom of several conditions and negatively impacts the quality of life of those affected. Fatigue is often a symptom of concern for people suffering from conditions such as fibromyalgia, chronic fatigue syndrome, cancer, and multiple sclerosis. Vitamins and minerals, playing essential roles in a variety of basic metabolic pathways that support fundamental cellular functions, may be important in mitigating physical and mental fatigue. Several studies have examined the potential benefits of nutrients on fatigue in various populations. The current review aimed to gather the existing literature exploring different nutrients' effects on fatigue. From the searches of the literature conducted in PubMed, Ovid, Web of Science, and Google scholar, 60 articles met the inclusion criteria and were included in the review. Among the included studies, 50 showed significant beneficial effects (p < 0.05) of vitamin and mineral supplementation on fatigue. Altogether, the included studies investigated oral or parenteral administration of nutrients including Coenzyme Q10, L-carnitine, zinc, methionine, nicotinamide adenine dinucleotide (NAD), and vitamins C, D and B. In conclusion, the results of the literature review suggest that these nutrients have potentially significant benefits in reducing fatigue in healthy individuals as well as those with chronic illness, both when taken orally and parenterally. Further studies should explore these novel therapies, both as adjunctive treatments and as sole interventions.

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.

L-Carnitine Stimulates In Vivo Carbohydrate Metabolism in the Type 1 Diabetic Heart as Demonstrated by Hyperpolarized MRI

The diabetic heart is energetically and metabolically abnormal, with increased fatty acid oxidation and decreased glucose oxidation. One factor contributing to the metabolic dysfunction in diabetes may be abnormal handling of acetyl and acyl groups by the mitochondria. L-carnitine is responsible for their transfer across the mitochondrial membrane, therefore, supplementation with L-carnitine may provide a route to improve the metabolic state of the diabetic heart. The primary aim of this study was to use hyperpolarized magnetic resonance imaging (MRI) to investigate the effects of L-carnitine supplementation on the in vivo metabolism of [1-¹³C]pyruvate in diabetes. Male Wistar rats were injected with either vehicle or streptozotocin (55 mg/kg) to induce type-1 diabetes. Three weeks of daily i.p. treatment with either saline or L-carnitine (3 g/kg/day) was subsequently undertaken. In vivo cardiac function and metabolism were assessed with CINE and hyperpolarized MRI, respectively. L-carnitine supplementation prevented the progression of hyperglycemia, which was observed in untreated streptozotocin injected animals and led to reductions in plasma triglyceride and ß-hydroxybutyrate concentrations. Hyperpolarized MRI revealed that L-carnitine treatment elevated pyruvate dehydrogenase flux by 3-fold in the diabetic animals, potentially through increased buffering of excess acetyl-CoA units in the mitochondria. Improved functional recovery following ischemia was also observed in the L-carnitine treated diabetic animals.

The effects of L-carnitine supplementation on lipid concentrations inpatients with type 2 diabetes: A systematic review and meta-analysis of randomized clinical trials

This meta-analysis was performed to assess the effect of L-carnitine supplementation on lipid profile. A systematic search were conducted in PubMed and Scopus to identify randomized clinical trials (RCTs) which evaluated the effects of L-carnitine on lipid profile. Pooled effect sizes were measured using random-effect model (Dersimonian-Laird). Meta-analysis showed that L-carnitine supplementation significantly reduced total cholesterol (TC) (weighted mean difference [WMD]: -8.17 mg/dL; 95% CI,-14.68 to -1.65, I²=52.2%, P = 0.041). Baseline level of TC was a source of heterogeneity, with a greater effect in studies with a baseline level of more than 200 mg/d (WMD: -11.93 mg/dL; 95% CI, -20.80 to-3.05). L-carnitine also significantly decreased low-density lipoprotein-cholesterol (LDL-C) (WMD:-5.22 mg/dL; 95% CI, -9.54 to -0.91, I²=66.7%, P = 0.010), and LDL-C level <100 mg/dL), trial duration,and L-carnitine dosage were potential sources of heterogeneity. L-carnitine supplementation appeared to have no significant effect on high-density lipoprotein-cholesterol (HDL-C) (WMD: -0.51 mg/dL;95% CI, -2.45 to 1.44) and triglyceride (TG) (WMD: 2.80 mg/dL; 95% CI, -8.09 to 13.69). This meta-analysisrevealed that L-carnitine may have favorable effects on lipid profile, especially LDL-C and TC. However, further RCTs are needed to confirm the veracity of these results, particularly among hyperlipidemic patients.

Fasting Therapy Contributes to the Improvement of Endothelial Function and Decline in Vascular Injury-Related Markers in Overweight and Obese Individuals via Activating Autophagy of Endothelial Progenitor Cells

Background

High body mass index- (BMI-) related vascular injury contributes to the pathogenesis of the atherosclerotic cardiovascular disease (ASCVD). Rigorous calorie restriction is one of the major lifestyle interventions to reduce vascular risk in overweight or obese individuals. However, the effects of fasting therapy (FT) on vascular function and the mechanism are still unclear. This study was aimed to investigate the impacts of FT on endothelial function, arterial stiffness, and circulating arterial damage parameters in overweight and obese individuals and possible mechanism.

Methods

Overweight and obese individuals participated in FT intervention (7-day very low calorie diet). Arterial function including brachial arterial flow-mediated dilation (FMD), brachial-ankle pulse wave velocity (baPWV), vascular injury-related markers including trimethylamine N-oxide (TMAO), and leptin and endothelial microparticles (EMPs) were assessed. Endothelial progenitor cells (EPCs) of these participants were isolated and cultured to investigate EPCs function. mRFP-GFP-LC3 confocal microscopy scanning and western blot were carried out to determine autophagy.

Results

After FT, body weight and BMI significantly decreased (81.76 ± 12.04 vs. 77.51 ± 12.06 kg, P < 0.01; 29.93 ± 2.82 vs. 28.47 ± 2.83 kg/m², P < 0.01). FT remarkably improved FMD (5.26 ± 1.34 vs. 6.25 ± 1.60%, P=0.01) while baPWV kept unchanged. TMAO and leptin levels decreased (3.96 ± 1.85 vs. 2.73 ± 1.33 μmol/L, P=0.044; 6814 ± 2639 vs. 3563 ± 2668 μmol/L, P < 0.01). EMPs showed a decreased tendency. EPCs function was significantly improved, autophagy fluorescence intensity was enhanced, and the level of Beclin1, Atg5, LC3 II/I also increased after starvation in vitro, and the effects were blocked by autophagy inhibitor.

Conclusions

Our present study demonstrated for the first time that FT markedly improves endothelial function and reduces the levels of arterial injury markers through improving EPCs function via activating autophagy. These findings provide a novel insight into FT as a lifestyle intervention strategy to promote the maintenance of vascular homeostasis in overweight or obese individuals. The trial was registered with ChiCTR1900024290.

Effects of l-carnitine supplementation on cardiovascular and bone turnover markers in patients with pemphigus vulgaris under corticosteroids treatment: A randomized, double-blind, controlled trial

Pemphigus vulgaris (PV) is a severe, bullous, autoimmune disease of the skin and mucous membranes. Corticosteroids are usually the main core treatment for controlling PV, which could lead to several side effects such as insulin resistance, osteoporosis, and cardiovascular disorders. The aim of this study is to evaluate the protective effects of l-carnitine (LC) supplementation in PV patients under corticosteroid treatment. In this randomized, double-blind, placebo-controlled clinical trial, 48 patients with PV were divided randomly into two groups to receive 2 g LC (n = 24) or a placebo (n = 24) for 8 weeks, respectively. Serum levels of osteopontin (OPN), bone morphogenic protein 4 (BMP4), cystatin C, systolic and diastolic blood pressure, 25 hydroxyvitamin D3, and LC were evaluated at the beginning and at the end of the study. LC supplementation demonstrated a significant increase in serum carnitine (p < .001). In addition, at the end of the trial, LC supplementation significantly decreased serum BMP4 (p = .003), OPN (p = .03), and cystatin C (p = .001) levels. There was no significant effect on blood pressure in comparison with the placebo. During study, no harmful side effects were reported by patients. These findings indicate that LC supplementation significantly leads to favorable changes in OPN, BMP4, and cystatin C in PV patients under corticosteroid therapy. However, further investigations are required to confirm these results.

Characteristics of Selected Antioxidative and Bioactive Compounds in Meat and Animal Origin Products

Meat and meat products have a high nutritional value. Besides major components, meat is rich in bioactive components, primarily taurine, l-carnitine, choline, alpha-lipoic acid, conjugated linoleic acid, glutathione, creatine, coenzyme Q10 and bioactive peptides. Many studies have reported their antioxidant and health-promoting properties connected with their lipid-lowering, antihypertensive, anti-inflammatory, immunomodulatory activity and protecting the organism against oxidative stress. The antioxidant activity of meat components results, among others, from the capability of scavenging reactive oxygen and nitrogen species, forming complexes with metal ions and protecting cells against damage. This review is focused to gather accurate information about meat components with antioxidant and biological activity.

The effects of L-carnitine supplementation on glycemic control: a systematic review and meta-analysis of randomized controlled trials

The findings of trials investigating the effect of L-carnitine administration on glycemic control are controversial. This meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of L-carnitine intake on glycemic control. Two authors independently searched electronic databases including MEDLINE, EMBASE, Cochrane Library, Web of Science, PubMed and Google scholar from 1990 until February 2019, in order to find relevant RCTs. 37 studies with 44 effect sizes met the inclusion criteria and were eligible for the meta-analysis. L-carnitine supplementation resulted in a significant reduction in fasting plasma glucose (FPG) (WMD: -4.57; 95 % CI: -6.88, -2.25), insulin (WMD: -1.21; 95 % CI: -1.85, -0.57), homeostatic model assessment for insulin resistance (HOMA-IR) (WMD: -0.67; 95 % CI: -0.90, -0.44) and HbA1C concentrations (WMD: -0.30; 95 % CI: -0.47, -0.13). L-Carnitine supplementation significantly reduced FPG, insulin, HOMA-IR, and HbA1c levels.

Does L-carnitine supplementation affect serum levels of enzymes mainly produced by liver? A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND AND AIMS

L-carnitine supplementation is proposed to reduce liver enzymes levels; however, previous findings were equivocal. The current systematic review and meta-analysis of randomized controlled clinical trials (RCTs) were performed to assess the effect of L-carnitine supplementation on serum levels of enzymes mainly produced by liver [alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGTP)].

METHODS

Online databases as well as the reference lists of relevant studies were searched from inception up to June 2019. The risk of bias in individual studies was assessed using Cochrane Collaboration's tool. Data were pooled using the random-effects model and expressed as mean differences (MDs) with 95% confidence intervals (CIs).

RESULTS

In total, 18 RCTs (1161 participants) met the eligibility criteria. L-carnitine supplementation dose ranged from 500 to 4000 mg/day. L-carnitine supplementation significantly reduced serum ALT (MD = - 8.65 IU/L, 95% CI - 13.40, - 3.90), AST (MD = - 8.52 IU/L, 95% CI - 12.16, - 4.89), and GGTP (MD = - 8.80 IU/L, 95% CI - 13.67, - 3.92) levels. The subgroup analysis showed that L-carnitine might be more effective in reducing the enzymes when supplemented in higher doses (≥ 2000 mg/day), for longer durations (> 12 weeks), and among patients with liver diseases. The meta-evidence was graded as "moderate" for ALT and AST, and "low" for GGTP according to NutriGrade scoring system.

CONCLUSION

L-carnitine supplementation significantly improves circulating ALT, AST and GGTP levels; therefore, it might positively affect liver function, especially among patients with liver diseases. Further high-quality RCTs are recommended to confirm our results.

Effects of Carnitine Administration on Carotid Intima-media Thickness and Inflammatory Factors in Patients with Polycystic Ovary Syndrome: A Randomized, Double-blind, Placebo-controlled Trial

Background:

This study was performed to evaluate the effects of carnitine administration on carotid intima-media thickness (CIMT) and inflammatory markers in women with polycystic ovary syndrome (PCOS).

Methods:

This randomized, double-blind, placebo-controlled trial was conducted among 60 women diagnosed with PCOS according to the Rotterdam criteria, aged 18–40 years. Participants were randomly allocated into two groups to intake either 250 mg/day carnitine (n = 30) or placebo (n = 30) for 12 weeks. High-resolution carotid ultrasonography was conducted at baseline and after the 12-week intervention.

Results:

After the 12-week intervention, compared with the placebo, carnitine supplementation resulted in a significant decrease in maximum levels of the left CIMT (−0.01 ± 0.02 vs. +0.002 mm ± 0.006 mm, P = 0.001), mean levels of the left CIMT (−0.01 ± 0.02 vs. +0.001 mm ± 0.01 mm, P = 0.001), maximum levels of the right CIMT (−0.01 ± 0.02 vs. +0.006 mm ± 0.01 mm, P < 0.001), and mean levels of the right CIMT (−0.01 ± 0.02 vs. +0.002 mm ± 0.01 mm, P = 0.001). Change in plasma nitric oxide (NO) (+2.4 ± 3.6 vs. +0.2 ± 2.3 μmol/L, P = 0.007) was significantly different between the supplemented patients and placebo group. We did not see any significant effect in serum high sensitivity C-reactive protein (hs-CRP) following the supplementation of carnitine compared with the placebo.

Conclusions:

Overall, carnitine administration for 12 weeks to participants with PCOS had beneficial effects on CIMT and plasma NO, but did not affect serum hs-CRP levels.

L-carnitine ameliorated weight loss in fasting therapy: A propensity score-matched study

l-carnitine infusion has been proven to reduce fasting-induced fatigue and hunger in patients with metabolic syndrome in our former study. However, the association between l-carnitine and clinical outcomes of fasting therapy is yet to be investigated. In this study, data from 192 patients who finished fasting therapy from September 2008 to July 2018 were reviewed, among which 142 patients received l-carnitine infusion in fasting regimen. Propensity matching was used to overcome retrospective bias. Patients' anthropometric measurements and metabolic markers were evaluated. After propensity matching, 40 patients were included in each group. Weight (-4.05 ± 1.65 kg vs -3.25 ± 1.68 kg, P = 0.031) and BMI (-1.51±0.61 kg/m² vs -1.20 ± 0.62 kg/m², P = 0.036) decreased in both groups, but significantly more in l-carnitine group, while diastolic blood pressure (-1.67±9.82 mmHg vs -6.21±8.83 mmHg, P = 0.043) and triglycerides (-0.18±0.63 mmol/L vs -1.05±1.70 mmol/L, P = 0.007) decreased significantly more in non-l-carnitine group compared between groups, blood glucose did not differ significantly between groups. l-carnitine can boost the positive effects of fasting therapy on weight loss and maintain the stability of blood pressure.

The effect of l-carnitine supplementation on lipid profile and glycaemic control in adults with cardiovascular risk factors: A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND & AIMS

Several randomized clinical trials (RCTs) have investigated the effect of l-carnitine supplementation on lipid profile and glycaemic control in adults with cardiovascular risk factors; however, the results were conflicting. Therefore, a meta-analysis was performed to assess the effect of l-carnitine on lipid profile and glycaemic control in adults with cardiovascular risk factors.

METHODS

We searched PubMed, Scopus, Cochrane Databases, Google Scholar, ProQuest, Web of Science and Embase for randomized, placebo-controlled human trials that investigated the effect of l-carnitine supplementation on lipid profile and glycaemic control up to April 2017. From the eligible trials, 24 articles were selected for the meta-analysis. The meta-analysis was performed in a random-effects model. Heterogeneity was determined by I² statistics and Cochrane Q test.

RESULTS

The result showed significant effect of l-carnitine on TC (WMD: -13.73 [95% CI: -22.28, -5.17] mg/dL; P < 0.001), LDL-C (WMD = - 7.70 [95% CI: - 11.80, -3.61]mg/dL; p < 0.001), HDL-C (WMD = 0.82 [95% CI: 0.44, 1.21] mg/dL; P > 0.001), Lp(a) (WMD = - 7.13 [95% CI: -9.82,- 4.43]mg/dL; P < 0.001), FPG (WMD = -6.25 [95% CI: -10.35, -2.16] mg/dL; P < 0.001), HbA1C (WMD (%) = - 0.35 [95% CI: -0.65,- 0.05]; p = 0.02) and HOMA-IR (WMD (%) = - 0.94 [95% CI: -1.89, -0.00]; P = 0.05). No effect of l-carnitine was detected in TG, Apo A-I and Apo B 100 on pooled effect size. Additionally, sensitivity analysis showed l-carnitine supplementation could improve glycaemic control, particularly along with hypocaloric diet.

CONCLUSION

This meta-analysis showed that l-carnitine supplementation could improve lipid profile levels, particularly in doses more than 1500 mg/day. More RCTs with large sample sizes, focusing on gut microbiome profiles and dietary patterns are needed to better understand the effect of l-carnitine on patients with cardiovascular risk factors.

Effects of L-carnitine supplementation on biomarkers of oxidative stress, antioxidant capacity and lipid profile, in patients with pemphigus vulgaris: a randomized, double-blind, placebo-controlled trial

BACKGROUND/OBJECTIVES

Pemphigus vulgaris (PV), as an autoimmune disease including mucosa and the skin, is associated with several complications and comorbidities. The present study planned to determine the effect of L-carnitine (LC) supplementation on biomarkers of oxidative stress (OS), antioxidant capacity and lipid profile in PV patients.Subjects/MethodsFifty two control and patients with PV, participated in the current randomized, double-blind, placebo-controlled clinical trial. The patients were allocated randomly to receive 2 g per day LC tartrate subdivided into two equal doses of 1 g before breakfast and dinner (n=26) or placebo (n=26) for 8 weeks. Anthropometric, lipid profile and OS values were determined at baseline and end of intervention period.

RESULTS

LC intake significantly reduced serum levels of triglycerides, total-, LDL- cholesterol and oxidative stress index (OSI; P<0.05). In addition, supplementation with LC resulted to a meaningful increase in levels of total antioxidant capacity (TAC) (P=0.05) and serum carnitine (P<0.001). LC intake revealed non-significant change in serum total oxidant capacity (P=0.15) and HDL- cholesterol (P=0.06) in comparison to the placebo.

CONCLUSIONS

LC consumption may have favorable results on TAC, OSI and lipid profiles in patients with PV. The results were in line with the idea that LC supplementation can be associated with positive effects on metabolic status and OS of patients with PV.European Journal of Clinical Nutrition advance online publication, 23 August 2017; doi:10.1038/ejcn.2017.131.

L-carnitine prevents metabolic steatohepatitis in obese diabetic KK-Ay mice

AIM

Pharmacological treatment for metabolic syndrome-related non-alcoholic steatohepatitis has not been established. We investigated the effect of L-carnitine, an essential substance for β-oxidation, on metabolic steatohepatitis in mice.

METHODS

Male KK-A^y mice were fed a high-fat diet (HFD) for 8 weeks, with supplementation of L-carnitine (1.25 mg/mL) in drinking water for the latter 4 weeks.

RESULTS

Serum total carnitine levels were decreased following HFD feeding, whereas the levels were reversed almost completely by L-carnitine supplementation. In mice given L-carnitine, exacerbation of hepatic steatosis and hepatocyte apoptosis was markedly prevented even though HFD feeding was continued. Body weight gain, as well as hyperlipidemia, hyperglycemia, and hyperinsulinemia, following HFD feeding were also significantly prevented in mice given L-carnitine. High-fat diet feeding elevated hepatic expression levels of carnitine palmitoyltransferase 1A mRNA; however, production of β-hydroxybutyrate in the liver was not affected by HFD alone. In contrast, L-carnitine treatment significantly increased hepatic β-hydroxybutyrate contents in HFD-fed mice. L-carnitine also blunted HFD induction in sterol regulatory element binding protein-1c mRNA in the liver. Furthermore, L-carnitine inhibited HFD-induced serine phosphorylation of insulin receptor substrate-1 in the liver. L-carnitine decreased hepatic free fatty acid content in 1 week, with morphological improvement of swollen mitochondria in hepatocytes, and increases in hepatic adenosine 5'-triphosphate content.

CONCLUSIONS

L-carnitine ameliorates steatohepatitis in KK-A^y mice fed an HFD, most likely through facilitating mitochondrial β-oxidation, normalizing insulin signals, and inhibiting de novo lipogenesis in the liver. It is therefore postulated that supplementation of L-carnitine is a promising approach for prevention and treatment of metabolic syndrome-related non-alcoholic steatohepatitis.

Oral carnitine supplementation reduces body weight and insulin resistance in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Limited data are available for evaluating the effects of oral carnitine supplementation on weight loss and metabolic profiles of women with polycystic ovary syndrome (PCOS). This study was designed to determine the effects of oral carnitine supplementation on weight loss, and glycaemic and lipid profiles in women with PCOS.

DESIGN, PATIENTS AND MEASUREMENTS

In a prospective, randomized, double-blind, placebo-controlled trial, 60 overweight patients diagnosed with PCOS were randomized to receive either 250 mg carnitine supplements (n = 30) or placebo (n = 30) for 12 weeks. Fasting blood samples were obtained at the beginning and the end of the study to quantify parameters of glucose homoeostasis and lipid concentrations.

RESULTS

At the end of the 12 weeks, taking carnitine supplements resulted in a significant reduction in weight (-2·7 ± 1·5 vs +0·1 ± 1·8 kg, P < 0·001), BMI (-1·1 ± 0·6 vs +0·1 ± 0·7 kg/m(2) , P < 0·001), waist circumference (WC) (-2·0 ± 1·3 vs -0·3 ± 2·0 cm, P < 0·001) and hip circumference (HC) (-2·5 ± 1·5 vs -0·3 ± 1·8 cm, P < 0·001) compared with placebo. In addition, compared with placebo, carnitine administration in women with PCOS led to a significant reduction in fasting plasma glucose (-0·38 ± 0·36 vs +0·11 ± 0·97 mmol/l, P = 0·01), serum insulin levels (-14·39 ± 25·80 vs +3·01 ± 37·25 pmol/l, P = 0·04), homoeostasis model of assessment-insulin resistance (-0·61 ± 1·03 vs +0·11 ± 1·43, P = 0·04) and dehydroepiandrosterone sulphate (-3·64 ± 7·00 vs -0·59 ± 3·20 μmol/l, P = 0·03).

CONCLUSIONS

Overall, 12 weeks of carnitine administration in PCOS women resulted in reductions in weight, BMI, WC and HC, and beneficial effects on glycaemic control; however, it did not affect lipid profiles or free testosterone.

Impact of L-carnitine on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled trials

We aimed to assess the impact of L-carnitine on plasma Lp(a) concentrations through systematic review and meta-analysis of available RCTs. The literature search included selected databases up to 31^st January 2015. Meta-analysis was performed using fixed-effects or random-effect model according to I² statistic. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence interval (CI). The meta-analysis showed a significant reduction of Lp(a) levels following L-carnitine supplementation (WMD: −8.82 mg/dL, 95% CI: −10.09, −7.55, p < 0.001). When the studies were categorized according to the route of administration, a significant reduction in plasma Lp(a) concentration was observed with oral (WMD: −9.00 mg/dL, 95% CI: −10.29, −7.72, p < 0.001) but not intravenous L-carnitine (WMD: −2.91 mg/dL, 95% CI: −10.22, 4.41, p = 0.436). The results of the meta-regression analysis showed that the pooled estimate is independent of L-carnitine dose (slope: −0.30; 95% CI: −4.19, 3.59; p = 0.878) and duration of therapy (slope: 0.18; 95% CI: −0.22, 0.59; p = 0.374). In conclusion, the meta-analysis suggests a significant Lp(a) lowering by oral L-carnitine supplementation. Taking into account the limited number of available Lp(a)-targeted drugs, L-carnitine might be an effective alternative to effectively reduce Lp(a). Prospective outcome trials will be required to fully elucidate the clinical value and safety of oral L-carnitine supplementation.

Transient severe hypercholesterolemia following bariatric surgery treated successfully with increased food intake

We describe a case of transient severe hypercholesterolemia after bariatric surgery treated successfully with increased food intake. A 25-y-old policeman who had sleeve gastrectomy for morbid obesity 10 mo previously presented with generalized weakness, constipation, and significant weight loss after severe dietary restriction. All his preoperative and prior investigations were normal. Further investigation revealed severe total and low-density lipoprotein hypercholesterolemia. After all other causes of secondary hypercholesterolemia were excluded, a diagnosis of starvation-induced hypercholesterolemia was made. The patient was therefore started on a normal mixed diet gradually increased to achieve satiation. His dietary intake, body weight, and lipid profile were monitored over a 3-mo period. Eventually his symptoms abated, weight increased, and lipid profile returned back to normal levels. Although dietary management of failed weight loss after bariatric surgery is the main priority for health professionals, this case illustrates the possible harm of severe dietary restriction after surgery and the need for judicious dietary and nutritional management.

Hepatic proteomic analysis revealed altered metabolic pathways in insulin resistant Akt1(+/-)/Akt2(-/-) mice

OBJECTIVE

The aim of this study was to identify liver proteome changes in a mouse model of severe insulin resistance and markedly decreased leptin levels.

METHODS

Two-dimensional differential gel electrophoresis was utilized to identify liver proteome changes in AKT1(+/-)/AKT2(-/-) mice. Proteins with altered levels were identified with tandem mass spectrometry. Ingenuity Pathway Analysis was performed for the interpretation of the biological significance of the observed proteomic changes.

RESULTS

11 proteins were identified from 2 biological replicates to be differentially expressed by a ratio of at least 1.3 between age-matched insulin resistant (Akt1(+/-)/Akt2(-/-)) and wild type mice. Albumin and mitochondrial ornithine aminotransferase were detected from multiple spots, which suggest post-translational modifications. Enzymes of the urea cycle were common members of top regulated pathways.

CONCLUSION

Our results help to unveil the regulation of the liver proteome underlying altered metabolism in an animal model of severe insulin resistance.