Exogenous L-carnitine ameliorates burn-induced cellular and mitochondrial injury of hepatocytes by restoring CPT1 activity

Targeting IGF2BP1 alleviated benzene hematotoxicity by reprogramming BCAA metabolism and fatty acid oxidation

Benzene is the main environmental pollutant and risk factor of childhood leukemia and chronic benzene poisoning. Benzene exposure leads to hematopoietic stem and progenitor cell (HSPC) dysfunction and abnormal blood cell counts. However, the key regulatory targets and mechanisms of benzene hematotoxicity are unclear. In this study, we constructed a benzene-induced hematopoietic damage mouse model to explore the underlying mechanisms. We identified that Insulin like growth factor 2 mRNA binding protein 1 (IGF2BP1) was significantly reduced in benzene-exposed mice. Moreover, targeting IGF2BP1 effectively mitigated damages to hematopoietic function and hematopoietic molecule expression caused by benzene in mice. On the mechanics, by metabolomics and transcriptomics, we discovered that branched-chain amino acid (BCAA) metabolism and fatty acid oxidation were key metabolic pathways, and Branched-chain amino acid transaminase 1 (BCAT1) and Carnitine palmitoyltransferase 1a (CPT1A) were critical metabolic enzymes involved in IGF2BP1-mediated hematopoietic injury process. The expression of the above molecules in the benzene exposure population was also examined and consistent with animal experiments. In conclusion, targeting IGF2BP1 alleviated hematopoietic injury caused by benzene exposure, possibly due to the reprogramming of BCAA metabolism and fatty acid oxidation via BCAT1 and CPT1A metabolic enzymes. IGF2BP1 is a potential regulatory and therapeutic target for benzene hematotoxicity.

Nicotinamide mitigates visceral leishmaniasis by regulating inflammatory response and enhancing lipid metabolism

BACKGROUND

Currently, treatment regimens for visceral leishmaniasis (VL) are limited because of the presence of numerous adverse effects. Nicotinamide, a readily available and cost-effective vitamin, has been widely acknowledged for its safety profile. Several studies have demonstrated the anti-leishmanial effects of nicotinamide in vitro. However, the potential role of nicotinamide in Leishmania infection in vivo remains elusive.

METHODS

In this study, we assessed the efficacy of nicotinamide as a therapeutic intervention for VL caused by Leishmania infantum in an experimental mouse model and investigated its underlying molecular mechanisms. The potential molecular mechanism was explored through cytokine analysis, examination of spleen lymphocyte subsets, liver RNA-seq analysis, and pathway validation.

RESULTS

Compared to the infection group, the group treated with nicotinamide demonstrated significant amelioration of hepatosplenomegaly and recovery from liver pathological damage. The NAM group exhibited parasite reduction rates of 79.7% in the liver and 86.7% in the spleen, respectively. Nicotinamide treatment significantly reduced the activation of excessive immune response in infected mice, thereby mitigating hepatosplenomegaly and injury. Furthermore, nicotinamide treatment enhanced fatty acid β-oxidation by upregulating key enzymes to maintain lipid homeostasis.

CONCLUSIONS

Our findings provide initial evidence supporting the safety and therapeutic efficacy of nicotinamide in the treatment of Leishmania infection in BALB/c mice, suggesting its potential as a viable drug for VL.

Incidence of atrial fibrillation after esophageal cancer surgery with L-carnitine use: a preliminary single-group interventional study

PURPOSE

We aimed to investigate the POAF rate and blood FABP4 levels after perioperative L-carnitine administration in patients with esophageal cancer.

METHODS

L-carnitine (3 g in three divided doses) was administered to 15 patients 2 days before and 3 days after surgery. POAF during the study period and blood FABP4 levels (ELISA) before and after L-carnitine administration were evaluated. Accurate 95% confidence intervals (CI) for POAF incidence and changes in blood FABP4 levels were calculated. The preoperative predicted POAF rate was calculated using an application for esophageal cancer. The correlation between FABP4 levels and the predicted POAF rate was analyzed using Pearson's coefficient (r).

RESULTS

Thirteen patients completed this study. The predicted POAF rate was 24% (17%, 34%) (median; interquartile range). The actual incidence of POAF was 7.7% (95% CI: 0.2-36%). Blood FABP4 levels changed from 10.3 to 7.0 ng/mL; the average change was - 3.3 (95% CI: - 6.6 to - 0.1). A positive correlation was found between preoperative FABP4 levels and the predicted POAF rates (r = 0.564).

CONCLUSIONS

The POAF rate after esophageal surgery was 7.7% for L-carnitine. L-carnitine may reduce blood FABP4 levels. This preliminary study will contribute to the planning of sample sizes in future randomized trials.

L-carnitine alleviates synovitis in knee osteoarthritis by regulating lipid accumulation and mitochondrial function through the AMPK-ACC-CPT1 signaling pathway

BACKGROUND

Knee osteoarthritis (KOA) is a disability-associated condition that is rapidly growing with the increase in obesity rates worldwide. There is a pressing need for precise management and timely intervention in the development of KOA. L-carnitine has been frequently recommended as a supplement to increase physical activity in obese individuals due to its role in fatty acid metabolism, immune disorders, and in maintaining the mitochondrial acetyl-CoA/CoA ratio. In this study, we aimed to investigate the anti-inflammatory effects of L-carnitine on KOA and delineate a potential molecular mechanism.

METHODS

Lipopolysaccharide-stimulated primary rat fibroblast-like synoviocytes (FLS) were treated with an AMP-activated protein kinase (AMPK) inhibitor or siRNA and carnitine palmitoyltransferase 1 (CPT1) siRNA to examine the synovial protective effects of L-carnitine. An anterior cruciate ligament transection model of rats was treated with an AMPK agonist (metformin) and CPT1 inhibitor (etomoxir) to define the therapeutic effects of L-carnitine.

RESULTS

L-carnitine displayed a protective effect against synovitis of KOA in vitro and in vivo experiments. Specifically, L-carnitine treatment can reduce synovitis by inhibiting AMPK-ACC-CPT1 pathway activation and showed an increase in fatty acid β-oxidation, a lower lipid accumulation, and a noticeable improvement in mitochondrial function.

CONCLUSIONS

Our data suggested that L-carnitine can mitigate synovitis in FLS and synovial tissue, and the underlying mechanism may be related to improving mitochondrial function and reducing lipid accumulation via the AMPK-ACC-CPT1 signaling pathway. Therefore, L-carnitine may be a potential treatment strategy for KOA.

β-Sitosterol mitigates hepatocyte apoptosis by inhibiting endoplasmic reticulum stress in thioacetamide-induced hepatic injury in γ-irradiated rats

The endoplasmic reticulum (ER) controls many biological functions besides maintaining the function of liver cells. Various studies reported the role of the ER stress and UPR signaling pathway in various liver diseases via triggering hepatocytes apoptosis. This study aims to investigate the suppressive effect of β-sitosterol (βS) on apoptosis associated with liver injury and ER stress.

METHODS

Liver damage in rats was induced by TAA (150 mg/kg I.P twice a week/3 weeks) and γ-irradiation (single dose 3.5 Gy) and treated with βS (20 mg/kg daily for 30 days). Serum aminotransferase activity, lipid profile and lipid metabolic factors were measured beside liver oxidative stress and inflammatory markers. Moreover, the hepatic expression of ER stress markers (inositol-requiring enzyme 1 alpha (IRE1α), X-box-binding protein 1 (XBP1) and CCAAT/enhancer binding protein homologous protein (CHOP) and apoptotic markers were detected together with histopathological examination.

RESULTS

βS diminished the aminotransferase activity, the oxidative stress markers as well as the inflammatory mediators. Furthermore, βS lowered the circulating TG and TC and the hepatic lipotoxicity via the suppression of lipogenesis (Srebp-1c) and improved the β-oxidation (Pparα and Cpt1a) together with the mitochondrial biogenesis (Pgc-1 α). Moreover, the upregulated levels of ER stress markers were reduced upon treatment with βS, which consequently attenuated hepatic apoptosis.

CONCLUSION

βS relieves hepatic injury, ameliorates mitochondrial biogenesis, and reduces lipotoxicity and apoptosis via inhibition of CHOP and ER stress response.

Maternal High-Fat Diet Impairs Placental Fatty Acid β-Oxidation and Metabolic Homeostasis in the Offspring

Maternal overnutrition can affect fetal growth and development, thus increasing susceptibility to obesity and diabetes in later life of the offspring. Placenta is the central organ connecting the developing fetus with the maternal environment. It is indicated placental fatty acid metabolism plays an essential role in affecting the outcome of the pregnancy and fetus. However, the role of placental fatty acid β-oxidation (FAO) in maternal overnutrition affecting glucose metabolism in the offspring remains unclear. In this study, C57BL/6J female mice were fed with normal chow or high-fat diet before and during pregnancy and lactation. The placenta and fetal liver were collected at gestation day 18.5, and the offspring's liver was collected at weaning. FAO-related genes and AMP-activated protein kinase (AMPK) signaling pathway were examined both in the placenta and in the human JEG-3 trophoblast cells. FAO-related genes were further examined in the liver of the fetuses and in the offspring at weaning. We found that dams fed with high-fat diet showed higher fasting blood glucose, impaired glucose tolerance at gestation day 14.5 and higher serum total cholesterol (T-CHO) at gestation day 18.5. The placental weight and lipid deposition were significantly increased in maternal high-fat diet group. At weaning, the offspring mice of high-fat diet group exhibited higher body weight, impaired glucose tolerance, insulin resistance and increased serum T-CHO, compared with control group. We further found that maternal high-fat diet downregulated mRNA and protein expressions of carnitine palmitoyltransferase 2 (CPT2), a key enzyme in FAO, by suppressing the AMPK/Sirt1/PGC1α signaling pathway in the placenta. In JEG-3 cells, protein expressions of CPT2 and CPT1b were both downregulated by suppressing the AMPK/Sirt1/PGC1α signaling pathway under glucolipotoxic condition, but were later restored by the AMPK agonist 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR). However, there was no difference in CPT2 and CPT1 gene expression in the liver of fetuses and offspring at weaning age. In conclusion, maternal high-fat diet can impair gene expression involved in FAO in the placenta by downregulating the AMPK signaling pathway, and can cause glucose and lipid dysfunction of offspring at weaning, indicating that placental FAO may play a crucial role in regulating maternal overnutrition and metabolic health in the offspring.