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

A simple strategy for d/l-carnitine analysis in food samples using ion mobility spectrometry and theoretical calculations

This work presents a straightforward approach to the separation d/l-carnitine (d/l-Carn) using ion mobility-mass spectrometry (IM-MS) and theoretical calculations. Natamycin (Nat) was used as separation reagent to interact with the Carn, metal ions (G) were employed as ligand, the resultant ternary complexes [d/l-Carn + Nat + G]+ were observed experimentally. IM-MS results revealed that d/l-Carn could be baseline separated via complex formation using Li+, Na+, K+, Rb+, and Cs+, with a maximum peak separation resolution (Rp-p) of 2.91; Theoretical calculations were performed to determine the optimal conformations of [d/l-Carn + Nat + Li/K]+, and the predicted collisional cross section values were consistent with the experimental values. Conformational analysis was used to elucidate the enantiomeric separation of d/l-Carn at the molecular level via the formation of ternary complexes. Furthermore, quantitative analyses for the determination of the enantiomers were established with effective linearity and acceptable sensitivity. Finally, the proposed method was successfully applied in the determination of d/l-Carn in food samples.

Mitochondrial Dysfunction: A Roadmap for Understanding and Tackling Cardiovascular Aging

Cardiovascular aging is a progressive remodeling process constituting a variety of cellular and molecular alterations that are closely linked to mitochondrial dysfunction. Therefore, gaining a deeper understanding of the changes in mitochondrial function during cardiovascular aging is crucial for preventing cardiovascular diseases. Cardiac aging is accompanied by fibrosis, cardiomyocyte hypertrophy, metabolic changes, and infiltration of immune cells, collectively contributing to the overall remodeling of the heart. Similarly, during vascular aging, there is a profound remodeling of blood vessel structure. These remodeling present damage to endothelial cells, increased vascular stiffness, impaired formation of new blood vessels (angiogenesis), the development of arteriosclerosis, and chronic vascular inflammation. This review underscores the role of mitochondrial dysfunction in cardiac aging, exploring its impact on fibrosis and myocardial alterations, metabolic remodeling, immune response remodeling, as well as in vascular aging in the heart. Additionally, we emphasize the significance of mitochondria-targeted therapies in preventing cardiovascular diseases in the elderly.

Detection and alterations of acetylcarnitine (AC) in human liver by 1 H MRS at 3T after supplementation with l-carnitine

PURPOSE

Acetylcarnitine can be assessed in vivo using proton MRS (1 H-MRS) with long TEs and this has been previously applied successfully in muscle. The aim of this study was to evaluate a 1 H-MRS technique for liver acetylcarnitine quantification in healthy humans before and after l-carnitine supplementation.

METHOD

Baseline acetylcarnitine levels were quantified using a STEAM sequence with prolonged TE in 15 healthy adults. Using STEAM with four different TEs was evaluated in phantoms. To assess reproducibility of the measurements, five of the participants had repeated 1 H-MRS without receiving l-carnitine supplementation. To determine if liver acetylcarnitine could be changed after l-carnitine supplementation, acetylcarnitine was quantified 2 h after intravenous l-carnitine supplementation (50 mg/kg body weight) in the other 10 participants. Hepatic lipids were also quantified from the 1 H-MRS spectra.

RESULTS

There was good separation between the acetylcarnitine and fat in the phantoms using TE = 100 ms. Hepatic acetylcarnitine levels were reproducible (coefficient of reproducibility = 0.049%) and there was a significant (p < 0.001) increase in the relative abundance after a single supplementation of l-carnitine. Hepatic allylic, methyl, and methylene peaks were not altered by l-carnitine supplementation in healthy volunteers.

CONCLUSION

Our results demonstrate that our 1 H-MRS technique could be used to measure acetylcarnitine in the liver and detect changes following intravenous supplementation in healthy adults despite the presence of lipids. Our techniques should be explored further in the study of fatty liver disease, where acetylcarnitine is suggested to be altered due to hepatic inflexibilities.

Efficacy and safety of Obex® in overweight and obese subjects: a randomised, double-blind, placebo-controlled clinical trial

BACKGROUND

Obex® may be helpful in reducing body weight and fat. The current study was carried out to evaluate the efficacy and safety of Obex® in the treatment of overweight and obese subjects.

METHODS

A double-blind, randomised, controlled phase III clinical trial was conducted involving 160 overweight and obese subjects (BMI ≥ 25.0 and < 40 kg/m²) aged 20 to 60 years, who received Obex® (n = 80) and placebo (n = 80) plus non-pharmacological treatment (physical activity and nutritional counseling). One sachet of Obex® or placebo were administered before the two main meals each day for 6 months. In addition to anthropometric measurements and blood pressure, fasting plasma and 2 h glucose levels during the oral glucose tolerance test, lipid profile, insulin, liver enzymes, creatinine, and uric acid (UA) were determined, insulin resistance (HOMA-IR) beta-cell function (HOMA-β) were assessed and insulin sensitivity (IS) was calculated with three indirect indexes.

RESULTS

After 3 months of Obex®, 48.3% of the participants (28/58) achieved complete success in reducing both weight and waist circumference by greater than or equal to 5% from baseline, as opposed to 26.0% (13/50) of individuals receiving placebo (p = 0.022). Compared to baseline, at 6 months no differences were found between the groups concerning anthropometric and biochemical measurements, except for high-density lipoprotein cholesterol (HDL-c) levels, which were higher in subjects receiving Obex® compared to those receiving placebo (p = 0.030). After 6 months of treatment, both groups showed reduced cholesterol and triglyceride levels (p < 0.012) compared to baseline value. However, only those intake Obex® showed reduced insulin concentrations and HOMA-IR, improved IS (p < 0.05), and decreased creatinine and UA levels (p < 0.005).

CONCLUSIONS

The consumption of Obex® together with lifestyle changes increased HDL-c, contributed to a rapid reduction of weight and waist circumference, as well as improved insulin homeostasis, which did not occur in the placebo group, and appears to be safe as an adjunct at conventional obesity treatment.

TRIAL REGISTRATION

Clinical trial protocol was registered in the Cuban public registry of clinical trials under code RPCEC00000267 on 17/04/2018 and also registered in the international registry of clinical trials, ClinicalTrials.gov, under code: NCT03541005 on 30/05/2018.

Ischemia promotes acyl-CoAs dephosphorylation and propionyl-CoA accumulation

INTRODUCTION

Our untargeted metabolic data unveiled that Acyl-CoAs undergo dephosphorylation, however little is known about these novel metabolites and their physiology/pathology relevance.

OBJECTIVES

To understand the relationship between acyl-CoAs dephosphorylation and energy status as implied in our previous work, we seek to investigate how ischemia (energy depletion) triggers metabolic changes, specifically acyl-CoAs dephosphorylation in this work.

METHODS

Rat hearts were isolated and perfused in Langendorff mode for 15 min followed by 0, 5, 15, and 30 minutes of global ischemia. The heart tissues were harvested for metabolic analysis.

RESULTS

As expected, ATP and phosphocreatine were significantly decreased during ischemia. Most short- and medium-chain acyl-CoAs progressively increased with ischemic time from 0 to 15 min, whereas a 30-minute ischemia did not lead to further change. Unlike other acyl-CoAs, propionyl-CoA accumulated progressively in the hearts that underwent ischemia from 0 to 30 min. Progressive dephosphorylation occurred to all assayed acyl-CoAs and free CoA regardless their level changes during the ischemia.

CONCLUSION

The present work further confirms that dephosphorylation of acyl-CoAs is an energy-dependent process and how this dephosphorylation is mediated warrants further investigations. It is plausible that dephosphorylation of acyl-CoAs and limited anaplerosis are involved in ischemic injuries to heart. Further investigations are warranted to examine the mechanisms of acyl-CoA dephosphorylation and how the dephosphorylation is possibly involved in ischemic injuries.

Developing a metabolic clearance rate framework as a translational analysis approach for hyperpolarized 13C magnetic resonance imaging

Hyperpolarized carbon-13 magnetic resonance imaging is a promising technique for in vivo metabolic interrogation of alterations between health and disease. This study introduces a formalism for quantifying the metabolic information in hyperpolarized imaging. This study investigated a novel perfusion formalism and metabolic clearance rate (MCR) model in pre-clinical stroke and in the healthy human brain. Simulations showed that the proposed model was robust to perturbations in T₁, transmit B₁, and k_PL. A significant difference in ipsilateral vs contralateral pyruvate derived cerebral blood flow (CBF) was detected in rats (140 ± 2 vs 89 ± 6 mL/100 g/min, p < 0.01, respectively) and pigs (139 ± 12 vs 95 ± 5 mL/100 g/min, p = 0.04, respectively), along with an increase in fractional metabolism (26 ± 5 vs 4 ± 2%, p < 0.01, respectively) in the rodent brain. In addition, a significant increase in ipsilateral vs contralateral MCR (0.034 ± 0.007 vs 0.017 ± 0.02/s, p = 0.03, respectively) and a decrease in mean transit time (31 ± 8 vs 60 ± 2 s, p = 0.04, respectively) was observed in the porcine brain. In conclusion, MCR mapping is a simple and robust approach to the post-processing of hyperpolarized magnetic resonance imaging.