Pharmacokinetic Evaluation of Intravenous Vitamin C: A Classic Pharmacokinetic Study

Reversal of cerebral ischaemia and hypoxia and of sickness behaviour by megadose sodium ascorbate in ovine Gram-negative sepsis

BACKGROUND

The mechanisms by which megadose sodium ascorbate improves clinical status in experimental sepsis is unclear. We determined its effects on cerebral perfusion, oxygenation, and temperature, and plasma levels of inflammatory biomarkers, nitrates, nitrites, and ascorbate in ovine Gram-negative sepsis.

METHODS

Sepsis was induced by i.v. infusion of live Escherichia coli for 31 h in unanaesthetised Merino ewes instrumented with a combination sensor in the frontal cerebral cortex to measure tissue perfusion, oxygenation, and temperature. Fluid resuscitation at 23 h was followed by i.v. megadose sodium ascorbate (0.5 g kg-1 over 30 min+0.5 g kg-1 h-1 for 6.5 h) or vehicle (n=6 per group). Norepinephrine was titrated to restore mean arterial pressure (MAP) to 70-80 mm Hg.

RESULTS

At 23 h of sepsis, MAP (mean [sem]: 85 [2] to 64 [2] mm Hg) and plasma ascorbate (27 [2] to 15 [1] μM) decreased (both P<0.001). Cerebral ischaemia (901 [58] to 396 [40] units), hypoxia (34 [1] to 19 [3] mm Hg), and hyperthermia (39.5 [0.1]°C to 40.8 [0.1]°C) (all P<0.001) developed, accompanied by malaise and lethargy. Sodium ascorbate restored cerebral perfusion (703 [121] units], oxygenation (30 [2] mm Hg), temperature (39.2 [0.1]°C) (all PTreatment<0.05), and the behavioural state to normal. Sodium ascorbate slightly reduced the sepsis-induced increase in interleukin-6, returned VEGF-A to normal (both PGroupxTime<0.01), and increased plasma ascorbate (20 000 [300] μM; PGroup<0.001). The effects of sodium ascorbate were not reproduced by equimolar sodium bicarbonate.

CONCLUSIONS

Megadose sodium ascorbate rapidly reversed sepsis-induced cerebral ischaemia, hypoxia, hyperthermia, and sickness behaviour. These effects were not reproduced by an equimolar sodium load.

Will AMPK be a potential therapeutic target for hepatocellular carcinoma?

Cancer is the disease that poses the greatest threat to human health today. Among them, hepatocellular carcinoma (HCC) is particularly prominent due to its high recurrence rate and extremely low five-year postoperative survival rate. In addition to surgical treatment, radiotherapy, chemotherapy, and immunotherapy are the main methods for treating HCC. Due to the natural drug resistance of chemoradiotherapy and targeted drugs, satisfactory results have not been achieved in terms of therapeutic efficacy and cost. AMP-Activated Protein Kinase (AMPK) is a serine/threonine protein kinase. It mainly coordinates the metabolism and transformation of energy between cells, which maintaining a balance between energy supply and demand. The processes of cell growth, proliferation, autophagy, and survival all involve various reaction of cells to energy changes. The regulatory role of AMPK in cellular energy metabolism plays an important role in the occurrence, development, treatment, and prognosis of HCC. Here, we reviewed the latest progress on the regulatory role of AMPK in the occurrence and development of HCC. Firstly, the molecular structure and activation mechanism of AMPK were introduced. Secondly, the emerging regulator related to AMPK and tumors were elaborated. Next, the multitasking roles of AMPK in the occurrence and development mechanism of HCC were discussed separately. Finally, the translational implications and the challenges of AMPK-targeted therapies for HCC treatment were elaborated. In summary, these pieces of information suggest that AMPK can serve as a promising specific therapeutic target for the treatment of HCC.

Antibiotic-Drug Interactions in the Intensive Care Unit: A Literature Review

Interactions between drugs are a common problem in Intensive Care Unit patients, as they mainly have a critical condition that often demands the administration of multiple drugs simultaneously. Antibiotics are among the most frequently used medications, as infectious diseases are often observed in ICU patients. In this review, the most important antibiotic-drug interactions, based on the pharmacokinetic and pharmacodynamic mechanisms, were gathered together and described. In particular, some of the most important interactions with main groups of antibacterial drugs were observed in patients simultaneously prescribed oral anticoagulants, NSAIDs, loop diuretics, and valproic acid. As a result, the activity of drugs can be increased or decreased, as dosage modification might be necessary. It should be noted that these crucial interactions can help predict and avoid negative consequences, leading to better patient recovery. Moreover, since there are other factors, such as fluid therapy or albumins, which may also modify the effectiveness of antibacterial therapy, it is important for anaesthesiologists to be aware of them.

Quantification of nine bufadienolides of Shexiang Tongxin Dropping Pills in rat plasma and tissues using UPLC-MS/MS and its application to healthy and ischemia-reperfusion rats pharmacokinetic studies

Shexiang Tongxin Dropping Pill (STDP) is a well-known compound preparation used in traditional Chinese medicine for treating cardiovascular diseases. Bufadienolides are the major active compounds of toad venom and are the key to the seven medicinal herbs that comprise STDP. In this study, a reliable and sensitive high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantitative determination of nine bufadienolides (bufalin, gamabufotalin, resibufogenin, marinobufagin, arenobufagin, desacetylcinobufagin, telocinobufagin, hellebrigenin, and hellebrigenol) in rat plasma and tissues (heart and liver). The chromatography column used was a Waters ACQUITY UPLC HSS-T3 column with gradient elution using mobile phase consisting of acetonitrile-water (0.1% formic acid added) at a flow rate of 0.25 mL/min. This method passed the methodological validation of plasma and tissues and was successfully applied to pharmacokinetic and tissue distribution studies after oral administration of STDP in healthy and ischemia-reperfusion (I/R) rats. This indicated that most bufadienolides were well absorbed and quickly distributed in the heart and liver. The area-under-the-curve (AUC)(0-t) of most analytes increased in a dose-dependent manner. Moreover, most of the tested components showed lower plasma and higher tissue concentrations in I/R rats than in healthy rats. The above results on the oral pharmacokinetics and tissue distribution may be helpful for the clinical application of STDP.

In vitro optimization of crushed drug-sensitive antituberculosis medication when administered via a nasogastric tube

IMPORTANCE

The incidence of tuberculosis (TB) in intensive care units (ICUs) can be as high as 3% in high-burden settings, translating to more than 7,500 patients admitted to the ICU annually. In resource-limited settings, the lack or absence of intravenous formulations of drug-sensitive antituberculosis medications necessitates healthcare practitioners to crush, dissolve, and administer the drugs to critically ill patients via a nasogastric tube (NGT). This off-label practice has been linked to plasma concentrations below the recommended target concentrations, particularly of rifampicin and isoniazid, leading to clinical failure and the development of drug resistance. Optimizing the delivery of crushed drug-sensitive antituberculosis medication via the NGT to critically ill patients is of utmost importance.

SERPINE1 and SERPINB7 as potential biomarkers for intravenous vitamin C treatment in non-small-cell lung cancer

High dose intravenous vitamin C (IVC) has been proposed as a pro-oxidant anticancer agent. However, there is a lack of biomarkers that are specific for this treatment. Here, we explored profiles of gene expression responding to IVC treatment in non-small cell lung cancer (NSCLC) cells as an effort for potential biomarker discovery. Genome-wide RNA-seq was performed in human NSCLC cell lines treated with pharmacological concentrations of vitamin C(VitC) for differential expression of genes. The identified genes were analyzed for correlations with patient prognosis using data from the Kaplan-Meier Plotter and the Human Protein Atlas databases. Further, tumor samples from a retrospective study of 153 NSCLC patients were analyzed with immunohistochemistry for expression of targeted genes, and patient prognosis was correlated to these genes. Two genes, namely SERPINE1 and SERPINB7 were found to be downregulated in NSCLC cells following VitC treatment. Combined patient data from the cohort analysis and online databases revealed that these 2 genes presented an unfavorable prognostic prediction of overall survival (OS) in NSCLC patients receiving standard of care. However, high expression level of these 2 genes were associated with prolonged OS in NSCLC patients receiving IVC in addition to standard of care. These data revealed that SERPINE1 and SERPINB7 have the potential to serve as predictive factors indicating favorable responses to IVC treatment in patients with NSCLC. Further validations are warranted.

Ex Vivo Anti-Leukemic Effect of Exosome-like Grapefruit-Derived Nanovesicles from Organic Farming-The Potential Role of Ascorbic Acid

Citrus fruits are a natural source of ascorbic acid, and exosome-like nanovesicles obtained from these fruits contain measurable levels of ascorbic acid. We tested the ability of grapefruit-derived extracellular vesicles (EVs) to inhibit the growth of human leukemic cells and leukemic patient-derived bone marrow blasts. Transmission electron microscopy and nanoparticle tracking analysis (NTA) showed that the obtained EVs were homogeneous exosomes, defined as exosome-like plant-derived nanovesicles (ELPDNVs). The analysis of their content has shown measurable amounts of several molecules with potent antioxidant activity. ELPDNVs showed a time-dependent antiproliferative effect in both U937 and K562 leukemic cell lines, comparable with the effect of high-dosage ascorbic acid (2 mM). This result was confirmed by a clear decrease in the number of AML blasts induced by ELPDNVs, which did not affect the number of normal cells. ELPDNVs increased the ROS levels in both AML blast cells and U937 without affecting ROS storage in normal cells, and this effect was comparable to ascorbic acid (2 mM). With our study, we propose ELPDNVs from grapefruits as a combination/supporting therapy for human leukemias with the aim to improve the effectiveness of the current therapies.

Pharmacological Ascorbate Elicits Anti-Cancer Activities against Non-Small Cell Lung Cancer through Hydrogen-Peroxide-Induced-DNA-Damage

Non-small cell lung cancer (NSCLC) poses a significant global health burden with unsatisfactory survival rates, despite advancements in diagnostic and therapeutic modalities. Novel therapeutic approaches are urgently required to improve patient outcomes. Pharmacological ascorbate (P-AscH-; ascorbate at millimolar concentration in plasma) emerged as a potential candidate for cancer therapy for recent decades. In this present study, we explore the anti-cancer effects of P-AscH- on NSCLC and elucidate its underlying mechanisms. P-AscH- treatment induces formation of cellular oxidative distress; disrupts cellular bioenergetics; and leads to induction of apoptotic cell death and ultimately reduction in clonogenic survival. Remarkably, DNA and DNA damage response machineries are identified as vulnerable targets for P-AscH- in NSCLC therapy. Treatments with P-AscH- increase the formation of DNA damage and replication stress markers while inducing mislocalization of DNA repair machineries. The cytotoxic and genotoxic effects of P-AscH- on NSCLC were reversed by co-treatment with catalase, highlighting the roles of extracellular hydrogen peroxide in anti-cancer activities of P-AscH-. The data from this current research advance our understanding of P-AscH- in cancer treatment and support its potential clinical use as a therapeutic option for NSCLC therapy.

Vitamin C inhibits the growth of colorectal cancer cell HCT116 and reverses the glucose-induced oncogenic effect by downregulating the Warburg effect

Malnutrition caused by insufficient nutritional supply may significantly hinder the quality of life among cancer patients. Sugar provides energy and nutritional support, but it also promotes cancer growth. Warburg effect is the reprogrammed glucose metabolic mode of cancer cells that meets the intensified ATP demand and biosynthesis. Vitamin C (VC) has anti-tumor effect. However, the relationship between cytotoxicity of VC on cancer cells and Warburg effect remains elusive, the effect of VC on glucose-induced oncogenic effect is also unclear. Based on colorectal cancer cell HCT116, our finding revealed that the discrepant oncogenic effect of different sugar is closely related to the intensification of Warburg effect, with glucose being the potent oncogenic component. Notably, as a potential Warburg effect inhibitor, VC suppressed cancer growth in a concentration-dependent manner and further reversed the glucose-induced oncogenic effect. Furthermore, VC protected tumor-bearing mice from insulin sensitivity impairment and inflammatory imbalance. These findings imply that VC might be a useful adjuvant treatment for cancer patients seeking to optimize nutritional support.

Biofunctionalization of natural extracts, trends in biological activity and kinetic release

The health benefits provided by plant matrices is due to the presence of certain compounds that, in studies carried out in vitro and in vivo, have shown to have biological activity in certain conditions, not only as a natural treatment against various conditions, but also for the quality of preventing chronic diseases, these compounds, already identified and studied, they can increase their biological function by undergoing structural chemical modifications or by being incorporated into polymer matrices that allow, in the first instance, to protect said compound and increase its bioaccessibility, as well as to preserve or increase the biological effects. Although the stabilization of compounds is an important aspect, it is also the study of the kinetic parameters of the system that contains them, since, due to these studies, the potential application to these systems can be designated. In this review we will address some of the work focused on obtaining compounds with biological activity from plant sources, the functionalization of extracts through double emulsions and nanoemulsions, as well as their toxicity and finally the pharmacokinetic aspects of entrapment systems.